Minoxidil - NutraHacker Journal Club
Phenol sulfotransferases (PSTs or phenol SULTs) catalyze the sulfate conjugation of phenolic drugs, xenobiotics, and monoamines. Two human PST isoforms have been defined biochemically, a thermostable (TS), or phenol-preferring, and a thermolabile (TL), or monoamine-preferring form. Pharmacogenetic studies showed that levels of both TS PST activity and TS PST thermal stability (an indirect measure of variation in amino acid sequence) in the platelet were regulated by genetic polymorphisms. Subsequent molecular genetic experiments revealed the existence of three human PST genes, two of which, SULT1A1 and SULT1A2, encode proteins with "TS PST-like" activity. We recently reported common nucleotide polymorphisms for SULT1A1 that are associated with variations in platelet TS PST activity and thermal stability. In the present experiments, we set out to determine whether functionally significant DNA polymorphisms also might exist for SULT1A2, to compare the biochemical properties of all common allozymes encoded by SULT1A2 and SULT1A1, and to study phenol SULT genotype-phenotype correlations in the human liver. We phenotyped 61 human liver biopsy samples for TS PST thermal stability and activity. The open reading frames of SULT1A2 and SULT1A1 then were amplified with the polymerase chain reaction and sequenced for each of these hepatic tissue samples. We observed 13 SULT1A2 alleles that encoded 6 allozymes. These alleles were in linkage disequilibrium with alleles for SULT1A1. Biochemical characterization of common allozymes encoded by both genes suggested that SULT1A1 was primarily responsible for "TS PST phenotype" in the human liver. In summary, both SULT1A2 and SULT1A1 have a series of common alleles encoding enzymes that differ functionally and are associated with individual differences in phenol SULT properties in the liver.
Molecular biology of the human cytosolic sulfotransferase gene superfamily implicated in the bioactivation of minoxidil and cholesterol in skin
Cytosolic sulfotransferases (ST) catalyze the sulfation of various phenolic agents, catecholamines, thyroid hormones, steroids, drugs, and procarcinogens, usually resulting in the inactivation and subsequent excretion of the compound. My laboratory's efforts have focused on the cloning of the human phenol-sulfating (PST) members of this gene superfamily, implicated in the bioactivation of the hair growth stimulant, minoxidil. At least two major forms of human PST enzymes have been characterized biochemically, the phenol-preferring PST (P-PST), and the catecholamine-preferring PST (M-PST). Various cDNAs have been cloned representing alleles of 3 gene loci termed as STP1, STP2, and STM, which were all mapped precisely to a small region on human chromosome 16p and to the homologous region of mouse chromosome 7. Human cosmid genomic clones have been sequenced to determine the genomic organization for each of the 3 highly-related genes. All contain 7 coding exons, with conserved intron-exon boundaries, and presumptive alternative tissue-specific promoters. At least one of the 3 PST-encoding genes is responsible for forming minoxidil sulfate in the lower outer root sheath of anagen hair follicles. The steroid sulfating genes, STD and STE, have been cloned by other laboratories. The isozyme products of these genes sulfate DHEA and estrogens, respectively. I hypothesize that either STE or STD is involved in the formation of cholesterol sulfate (CS) in epidermal keratinocytes. CS has been demonstrated by other groups to be an activator of keratinocyte Protein Kinase Ceta, which subsequently results in the activation of epidermal transglutaminase and formation of the cornified envelop. STE or STD might also be involved in bioinactivation of estrogens and androgens within skin. Our recent unpublished results have focused on elucidating the patterns of ST gene expression in cultured keratinocytes and fibroblasts derived from human skin using RT-PCR, to understand which of the 5 different ST genes in involved in the regulation of keratinocyte differentiation and minoxidil-induced hair growth.
Association between functional genetic polymorphisms of human sulfotransferases 1A1 and 1A2
Three human phenol sulfotransferases, provisionally named SULT1A1, 1A2 and 1A3, show 91-96% homology of their amino acid sequences and are encoded by neighbouring gene loci. Functional genetic polymorphisms are known for two of these sulfotransferases. In SULT1A1, a G to A transition leads to an Arg213 to His exchange and eliminates a Bsp143II restriction site. SULT1A1*His shows lower enzyme activity and thermostability than SULT1A1*Arg. In SULT1A2, an A to C transversion causes an Asn235 to Thr exchange and introduces a BpiI restriction site. Enzyme SULT1A2*Thr is less active than SULT1A2*Asn. These substitutions were detected by restriction fragment length polymorphism analyses of genomic sequences amplified by polymerase chain reaction. Despite the high similarity between the different human SULT1A genes, it was possible to amplify specifically the polymorphic parts of either SULT1A1 or 1A2, but not the homologous sequences of the other SULT, by setting the forward primer into intron 6. DNA from 300 adult male Caucasian subjects was analysed. Allele frequencies were 0.63 and 0.37 for SULT1A1*Arg and *His, and 0.62 and 0.38 for SULT1A2*Asn and *Thr, respectively. The frequency of the haplotype SULT1A1*Arg/SULT1A2*Asn (0.61) was nearly as high as the allele frequencies of its components. The same was observed for the haplotype SULT1A1*His/SULT1A2*Thr, whose frequency was 0.35. In contrast, haplotypes 1A1*Arg/1A2*Thr and 1A1*His/1A2*Asn were very rare. Their frequencies (0.02 each) were less than 10% of the figures expected in an independent distribution. The results demonstrate a strong association of the alleles producing the more active enzyme variants (SULT1A1*Arg and SULT1A2*Asn) and of those encoding the less active variants (SULT1A1*His and SULT1A2*Thr).
Carboxyl residues in the active site of human phenol sulfotransferase (SULT1A1)
The carboxyl-specific amino acid modification reagent, Woodward's reagent K (WK), was utilized to characterize carboxyl residues (Asp and Glu) in the active site of human phenol sulfotransferase (SULT1A1). SULT1A1 was purified using the pMAL-c2 expression system in E. coli. WK inactivated SULT1A1 activity in a time- and concentration-dependent manner. The inactivation followed first-order kinetics relative to both SULT1A1 and WK. Both phenolic substrates and adenosine 3'-phosphate 5'-phosphosulfate (PAPS) protected against the inactivation, which suggests the carboxyl residue modification causing the inactivation took place within the active site of the enzyme. With partially inactivated SULT1A1, both V(max) and K(m) changed for PAPS, while for phenolic substrates, V(max) decreased and K(m) did not change significantly. A computer model of the three-dimensional structure of SULT1A1 was constructed based on the mouse estrogen sulfotransferase (mSULT1E1) X-ray crystal structure. According to the model, Glu83, Asp134, Glu246, and Asp263 are the residues likely responsible for the inactivation of SULT1A1 by WK. According to these results, five SULT1A1 mutants, E83A, D134A, E246A, D263A, and E151A, were generated (E151A as control mutant). Specific activity determination of the mutants demonstrated that E83A and D134A lost almost 100% of the catalytic activity. E246A and D263A also decreased SULT1A1 activity, while E151A did not change SULT1A1 catalytic activity significantly. This work demonstrates that carboxyl residues are present in the active site and are important for SULT1A1 catalytic activity. Glu83 and E134 are essential amino acids for SULT1A1 catalytic activity.
Sulfation pharmacogenetics: SULT1A1 and SULT1A2 allele frequencies in Caucasian, Chinese and African-American subjects
Sulfotransferase (SULT) enzymes catalyze the sulfate conjugation of drugs, other xenobiotics, neurotransmitters and hormones. The genes for SULT1A1 and SULT1A2 contain common genetic polymorphisms that are associated with individual variations in levels of enzyme activity as well as variations in biochemical and physical properties. We set out to compare the frequencies of common SULT1A1 and SULT1A2 alleles in Caucasian, Chinese and African-American subjects. Allele frequencies for SULT1A1*1, *2 and *3 in 242 Caucasian subjects were 0.656, 0.332 and 0.012, respectively. Frequencies of those same alleles were significantly different in 290 Chinese subjects: 0.914, 0.080 and 0.006, respectively, as were frequencies in 70 African-American subjects: 0.477, 0.294 and 0.229, respectively. Ethnic variation in allele frequencies was also observed for SULT1A2, with frequencies in Caucasian subjects for SULT1A2*1, *2 and *3 of 0.507, 0.389 and 0.104; frequencies in Chinese of 0.924 and 0.076 with no *3 alleles observed; and, finally, in African-Americans frequencies of 0.637, 0.249 and 0.114, respectively. We also found that SULT1A1*2 and SULT1A2*2, the most common variant alleles for these two genes, were in positive linkage disequilibrium in all three populations studied, with D' values of 0.776 in Caucasian (P < 0.001), 0.915 in Chinese (P < 0.001) and 0.864 in African-American subjects (P < 0.001). These observations represent a step towards determining the possible functional implications for individual variations in sulfate conjugation of common genetic polymorphisms for SULT1A1 and SULT1A2.
Association between sulfotransferase 1A1 genotype and survival of breast cancer patients receiving tamoxifen therapy
Background: Human sulfotransferase 1A1 (SULT1A1) catalyzes the sulfation of a variety of phenolic and estrogenic compounds, including 4-hydroxytamoxifen (4-OH TAM), the active metabolite of tamoxifen. A functional polymorphism in exon 7 of the SULT1A1 gene (SULT1A1*2) has been described that generates an enzyme that has approximately twofold lower activity and is less thermostable than that of the common allele SULT1A1*1. We investigated the hypothesis that that high sulfation activity would increase the elimination of 4-OH TAM by examining whether the presence of this polymorphism affects the efficacy of tamoxifen therapy. Methods: We examined the relationship between the SULT1A1*2 allele and survival in a cohort of 337 women with breast cancer who received tamoxifen (n = 160) or who did not (n = 177). SULT1A1 genotype was determined by restriction fragment polymorphism analysis. Patient survival was evaluated according to SULT1A1 genotype using Kaplan-Meier survival functions. Hazard ratios (HRs) were calculated from adjusted Cox proportional hazards modeling. All statistical tests were two-sided. Results: Among tamoxifen-treated patients, those who were homozygous for the SULT1A1*2 low-activity allele had approximately three times the risk of death (HR = 2.9, 95% confidence interval [CI] = 1.1 to 7.6) as those who were homozygous for the common allele or those who were heterozygous (SULT1A1*1/*2). Among patients who did not receive tamoxifen, there was no association between survival and SULT1A1 genotype (HR = 0.7, 95% CI = 0.3 to 1.5). Conclusions: Sulfation of 4-OH TAM provides a previously unanticipated benefit, possibly due to alterations in the bioavailability of the active metabolite or to undefined estrogen receptor-mediated events. These data alternatively suggest that variability in the metabolism of tamoxifen may affect its efficacy.
Sulfation through the looking glass--recent advances in sulfotransferase research for the curious
Members of the cytosolic sulfotransferase (SULT) superfamily catalyse the sulfation of a multitude of xenobiotics, hormones and neurotransmitters. Humans have at least 10 functional SULT genes, and a number of recent advances reviewed here have furthered our understanding of SULT function. Analysis of expression patterns has shown that sulfotransferases are highly expressed in the fetus, and SULTs may in fact be a major detoxification enzyme system in the developing human. The X-ray crystal structures of three SULTs have been solved and combined with mutagenesis experiments and molecular modelling, they have provided the first clues as to the factors that govern the unique substrate specificities of some of these enzymes. In the future these and other studies will facilitate prediction of the fate of chemicals metabolised by sulfation. Variation in sulfation capacity may be important in determining an individual's response to xenobiotics, and there has been an explosion in information on sulfotransferase polymorphisms and their functional consequences, including the influence of SULT1A1 genotype on susceptibility to colorectal and breast cancer. Finally, the first gene knockout experiments with SULTs have recently been described, with the generation of estrogen sulfotransferase deficient mice in which reproductive capacity is compromised. Our improved understanding of these enzymes will have significant benefits in such diverse areas as drug design and development, cancer susceptibility, reproduction and development.
The relationship among the polymorphisms of SULT1A1, 1A2 and different types of cancers in Taiwanese
Sulfotransferase (SULT) enzymes play an important role in the detoxification, metabolism and bioactivation of numerous xenobiotics, many dietary and environmental mutagens, drugs, neurotransmitters and hormones. The genes for SULT1A1 and SULT1A2 contain common genetic polymorphisms that are associated with individual variations in the level of enzyme activities as well as variations of biochemical and physical properties. We developed a PCR-RFLP method to analyze the frequencies of SULT1A1 and SULT1A2 alleles among cancerous patients and normal controls in Taiwan. The results showed that SULT1A1*1 and SULT1A2*1 were in positive linkage disequilibrium. Neither SULT1A1*3 nor SULT1A2*3 were found in this study. The frequencies of SULT1A1*2 and SULT1A2*2 for hepatic, colon, lung, oral, gastric, renal and cervical cancerous patients were 3.95, 5.56, 4.92, 3.84, 2.70, 7.41 and 4.50%, respectively. No statistical significance was found for these cancer patients after comparison with normal controls (4.0%) for the allelic frequencies of SULT1A1*2 and SULT1A2*2.
Arginine residues in the active site of human phenol sulfotransferase (SULT1A1)
Cytosolic sulfotransferases (STs) catalyze the sulfation of hydroxyl containing compounds. Human phenol sulfotransferase (SULT1A1) is the major human ST that catalyzes the sulfation of simple phenols. Because of its broad substrate specificity and lack of endogenous substrates, the biological function of SULT1A1 is believed to be an important detoxification enzyme. In this report, amino acid modification, computer structure modeling, and site-directed mutagenesis were used for studies of Arg residues in the active site of SULT1A1. The Arg-specific modification reagent, 2,3-butanedione, inactivated SULT1A1 in an efficient, time- and concentration-dependent manner, suggesting Arg residues play an important role in the catalytic activity of SULT1A1. According to the computer model, Arg78, Arg130, and Arg257 may be important for SULT1A1 catalytic activity. Site-directed mutagenesis results demonstrated that the positive charge on Arg78 is not critical for SULT1A1 because R78A is still active. In contrast, a negative charge at this position, R78E, completely inactivated SULT1A1. Arg78 is in close proximity to the site of sulfuryl group transfer. Arg257 is located very close to the 3'-phosphate in adenosine 3'-phosphate 5'-phosphosulfate (PAPS). Site-directed mutagenesis demonstrated that Arg257 is critical for SULT1A1: both R257A and R257E are inactive. Although Arg130 is also located very close to the 3'-phosphate of PAPS, R130A and R130E are still active, suggesting that Arg130 is not a critical residue for the catalytic activity of SULT1A1. Computer modeling suggests that the ionic interaction between the positive charge on Arg257, and the negative charge on 3'-phosphate is the primary force stabilizing the specific binding of PAPS.
Pharmacogenetics of antihypertensive drug responses
The blood pressure (BP) response to any single antihypertensive drug is characterized by marked interindividual variation, and the known predictors of response are of limited value in identifying the optimum drug for an individual patient. Analysis of genetic variation has the potential to improve our understanding of determinants of antihypertensive drug response in order to individualize drug selection. Genetic variation can influence both pharmacokinetic and pharmacodynamic mechanisms underlying variation in drug response. Classic pharmacogenetic investigations have identified variations in single genes that have a large effect on antihypertensive drug metabolism and are inherited in a Mendelian fashion. These include a polymorphism in the CYP2D6 gene, encoding a cytochrome p450 family member involved in phase I drug metabolism, and polymorphisms in genes encoding enzymes involved in phase II drug metabolism, including N-acetyltransferase (NAT2), catechol-O-methyltransferase (COMT), and phenol sulfotransferase (P-PST, SULT1A1). Although these polymorphisms have major effects on the pharmacokinetic profiles of both commonly used antihypertensive drugs such as metoprolol (CYP2D6), and lesser used drugs such as hydralazine (NAT2), methyldopa (COMT), and minoxidil (SULT1A1), they have not been shown to influence variation in the antihypertensive effect of these drugs at conventional doses. Interest is now focused on identifying genetic polymorphisms that influence the pharmacodynamic determinants of antihypertensive response. Using a candidate gene approach, such polymorphisms have been identified in genes encoding alpha-adducin (ADD1), subunits of G-proteins (GNB3 and GNAS1), the beta(1)-adrenergic receptor (ADRB1), endothelial nitric oxide synthase (NOS3), and components of the renin-angiotensin-aldosterone system (angiotensinogen [AGT], angiotensin converting enzyme [ACE], the angiotensin type I receptor [AGTR1], and aldosterone synthase [CYP11B2]). These polymorphisms have been shown to influence the BP response to diuretics (ADD1, GNB3, NOS3, and ACE), beta-blockers (GNAS1 and ADRB1), ACE inhibitors (AGT, ACE, and AGTR1), angiotensin receptor blockers (ACE and CYP11B2), and clonidine (GNB3).An emerging consensus from these studies is that single gene effects on antihypertensive drug responses are small, and even the combined effects of all presently known polymorphisms do not account for enough variation in response to be clinically useful. New genome-wide scanning techniques may lead to the identification of genes previously unsuspected of influencing drug response. Additional requirements for pharmacogenetic approaches to become clinically useful are the characterization of the effects of haplotypes and multi-locus genotypes on drug response, and consideration of gene-by-environment interactions. Such studies will require huge sample sizes and novel statistical methods, but the theoretical and technical framework is in place to make this possible.
UDP-glucuronosyltransferase and sulfotransferase polymorphisms, sex hormone concentrations, and tumor receptor status in breast cancer patients
Introduction: UDP-glucuronosyltransferase (UGT) and sulfotransferase (SULT) enzymes are involved in removing sex hormones from circulation. Polymorphic variation in five UGT and SULT genes - UGT1A1 ((TA)6/(TA)7), UGT2B4 (Asp458Glu), UGT2B7 (His268Tyr), UGT2B15 (Asp85Tyr), and SULT1A1 (Arg213His)--may be associated with circulating sex hormone concentrations, or the risk of an estrogen receptor-negative (ER-) or progesterone receptor-negative (PR-) tumor. Methods: Logistic regression analysis was used to estimate the odds ratios of an ER- or PR- tumor associated with polymorphisms in the genes listed above for 163 breast cancer patients from a population-based cohort study of women in western Washington. Adjusted geometric mean estradiol, estrone, and testosterone concentrations were calculated within each UGT and SULT genotype for a subpopulation of postmenopausal breast cancer patients not on hormone therapy 2-3 years after diagnosis (n = 89). Results: The variant allele of UGT1A1 was associated with reduced risk of an ER- tumor (P for trend = 0.03), and variants of UGT2B15 and SULT1A1 were associated with non-statistically significant risk reductions. There was some indication that plasma estradiol and testosterone concentrations varied by UGT2B15 and SULT1A1 genotypes; women with the UGT2B15 Asp/Tyr and Tyr/Tyr genotypes had higher concentrations of estradiol than women with the Asp/Asp genotype (P = 0.004). Compared with women with the SULT1A1 Arg/Arg and Arg/His genotypes, women with the His/His genotype had elevated concentrations of testosterone (P = 0.003). Conclusions: The risk of ER- breast cancer tumors may vary by UGT or SULT genotype. Further, plasma estradiol and testosterone concentrations in breast cancer patients may differ depending on some UGT and SULT genotypes.
All-trans retinoic acid induction of sulfotransferases
All-trans retinoic acid is the bioactive form of vitamin A (retinol). Retinoids have been used clinically as therapeutic agents against a number of cancers. Retinoids have been reported to induce the phase I drug metabolizing enzymes, cytochrome P-450s. In contrast, effects of retinoids on sulfotransferases have not been as well studied. The present investigation evaluates the role of retinoic acid on the expression of aryl sulfotransferase IV and hydroxysteroid sulfotransferase a in male and female Sprague-Dawley rat liver and intestine. Cultured human hepatic carcinoma cells (Hep G2) and intestinal carcinoma cells (Caco-2) were also used to study retinoic acid's effect on simple phenol sulfating sulfotransferase, dehydroepiandrosterone sulfotransferase and oestrogen sulfotransferase. Enzyme assay and Western blot were used to determine sulfotransferase protein expression. Retinoic acid induced aryl sulfotransferase IV in liver of female rats and sulfotransferase a in liver of male rats. Intestinal rat aryl sulfotransferase IV and sulfotransferase a in male rats and intestinal aryl sulfotransferase IV in female rats were also induced after retinoic acid treatment. In Hep G2 and Caco-2 cells, retinoic acid differentially induced the three human sulfotransferase isoforms. In general, intestinal sulfotransferases were found to be more responsive than hepatic sulfotransferases to retinoic acid treatment. mRNA expressions were investigated using reverse transcription polymerase chain reaction with gene specific primers. Reverse transcription polymerase chain reaction results are in good agreement with enzyme activity and Western blot results. This suggests that retinoic acid induction of sulfotransferases is at the transcriptional level.
Common genetic polymorphisms in the 5'-flanking region of the SULT1A1 gene: haplotypes and their association with platelet enzymatic activity
SULT1A1 is a phase II detoxification enzyme involved in the biotransformation of a wide variety of endogenous and exogenous phenolic compounds. Human platelet SULT1A1 enzymatic activity shows marked inter-individual variability and a common coding polymorphism, SULT1A1*1/*2, has been described that accounts for a proportion of this variability. We examined the 5'-flanking region of the SULT1A1 gene to determine if genetic variability in this portion of the gene influenced enzymatic activity. Direct sequencing revealed five common genetic polymorphisms (-624G>C, -396G>A, -358A>C, -341C>G and -294T>C) that were present at different allele frequencies in Caucasian, African-American and Chinese groups. Platelet SULT1A1 enzymatic activity was significantly correlated with individual promoter region polymorphisms and the associations were different between African-Americans and Caucasians. Haplotypes were constructed and platelet enzymatic activity according to haplotype was examined. The haplotypes were also significantly correlated with activity; haplotypes GAACT and GGACT (accounting for 13% and 5% of inter-individual variability in platelet activity, respectively) were important in Caucasians while haplotypes GAACC, GAACT and GGACC (accounting for 8%, 5% and 4% of variability) were significantly associated with activity in African-Americans. The coding region polymorphism, SULT1A1*1/*2 was in linkage disequilibrium with the promoter region polymorphisms and showed no effect on activity when examined in the context of the 5'-flanking region polymorphisms. These studies indicate that variation in the promoter region of the SULT1A1 gene exerts a significant influence on enzymatic activity.
Genetic polymorphisms and linkage disequilibrium of sulfotransferase SULT1A1 and SULT1A2 in a Korean population: comparison of other ethnic groups
Aims: To determine the allele frequencies of sulfotransferases (SULTs) 1A1 and 1A2 and their linkage disequilibrium in a Korean population and compare them with those of other ethnic groups. Methods: Genotypes of the SULT1A1*1, *2, and *3 and SULT1A2*1, *2, and *3 allelic variants were determined in 234 Korean subjects using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) methods. Results: Allele frequencies for SULT1A1*1 and *2 were 0.876 [95% confidence interval (CI), 0.843-0.905] and 0.124 (95% CI, 0.096-0.157), respectively. Similarly, those for SULT1A2*1 and *2 were 0.885 (95% CI, 0.852-0.912) and 0.115 (95% CI, 0.088-0.150), respectively. However, no subject with SULT1A1*3 or SULT1A2*3 was detected. These genotype distributions are similar to those of Asian populations including the Chinese and Japanese, but quite different from other ethnic groups such as African-Americans and Caucasians. The expected allelic frequencies of SULT1A1 and SULT1A2 at Hardy-Weinberg equilibrium are quite similar to the observed distributions in the population. SULT1A1*2 and SULT1A2*2, the most common variant alleles of these two genes, are strongly and positively linked in the Korean population (D' = 0.8919, chi2 = 343.24, P = 0.0034). Conclusions: SULT1A1*2 and SULT1A2*2 are the major allelic variants in the Korean population, whereas the SULT1A1*3 and SULT1A2*3 alleles were not found. SULT1A1*2 and SULT1A2*2 are strongly linked.
Sulfotransferase (SULT) 1A1 polymorphic variants *1, *2, and *3 are associated with altered enzymatic activity, cellular phenotype, and protein degradation
The superfamily of sulfotransferase (SULT) enzymes catalyzes the sulfate conjugation of several pharmacologically important endo- and xenobiotics. SULT1A1 catalyzes the sulfation of small planar phenols such as neurotransmitters, steroid hormones, acetaminophen, and p-nitrophenol (PNP). Genetic polymorphisms in the human SULT1A1 gene define three alleles, SULT1A1*1, *2, and *3. The enzyme activities of the SULT1A1 allozymes were studied with a variety of substrates, including PNP, 17beta-estradiol, 2-methoxyestradiol, catecholestrogens, the antiestrogen 4-hydroxytamoxifen (OHT), and dietary flavonoids. Using purified recombinant SULT1A1 protein, marked differences in *1, *2, and *3 activity toward every substrate studied were noted. Substrate inhibition was observed for most substrates. In general, the trend in V(max) estimates was *1 > *3 > *2; however, V(max)/K(m) estimate trends varied with substrate. In MCF-7 cells stably expressing either SULT1A1*1 or *2, the antiestrogenic response to OHT was found to be allele-specific: the cells expressing *2 exhibited a better antiproliferative response. The intracellular stability of the *1 and *2 allozymes was examined in insect as well as mammalian cells. The SULT1A1*2 protein had a shorter half-life than the *1 protein. In addition, the *2 protein was ubiquitinated to a greater extent than *1, suggesting increased degradation via a proteasome pathway. The results of this study suggest marked differences in activity of polymorphic SULT1A1 variants, including SULT1A1*3, toward a variety of substrates. These differences are potentially critical for understanding interindividual variability in drug response and toxicity, as well as cancer risk and incidence.
Pharmacogenetics of human cytosolic sulfotransferases
Cytosolic sulfotransferases (SULTs) are phase II detoxification enzymes that are involved in the biotransformation of a wide variety of structurally diverse endo- and xenobiotics, including many therapeutic agents and endogenous steroids. Single-nucleotide polymorphisms (SNPs) in SULTs have functional consequences on the translated protein. For the most part, these SNPs are fairly uncommon in the population, but some, most notably for SULT isoform 1A1, are commonly found and have been associated with cancer risk for a variety of tumor sites and also with response to therapeutic agents. SNPs in the hydroxysteroid sulfotransferase, SULT2A1, have been identified in African-American subjects and influence the ratio of plasma DHEA:DHEA-S. This modification could potentially influence cancer risk in steroidogenic tissues. SNPs in many SULTs are ethnically distributed, another factor that could influence SULT pharmacogenetics. Finally, genetic variation has also been identified in 3'-phosphoadenoside 5'-phosphosulfate synthetase (PAPPS), the enzymes responsible for producing the obligatory cosubstrate for all sulfotransferases. Taken together, this variability could substantially influence the disposition of drugs metabolized by SULTs. Elucidation of the basis and effect of variability in sulfation could greatly impact individualized therapy in the future.
Human SULT1A1 gene: copy number differences and functional implications
SULT1A1, which catalyzes the sulfate conjugation of a wide variety of natural and synthetic compounds, is genetically polymorphic. Biochemical and pharmacogenetic studies have demonstrated that individual variation in the level of enzyme activity is inherited. Common single-nucleotide polymorphisms (SNPs) located in the open reading frame and in the 5'-flanking region (5'-FR) may account for a portion of this individual variation. In this study, we demonstrate the presence of SULT1A1 gene deletions and duplications, representing an additional source of variability in the metabolic activity of this enzyme. A quantitative multiplex PCR assay was used to measure the extent of copy number differences and the frequency of these events in different populations. An analysis of DNA from 362 Caucasian-American and 99 African-American showed the presence of 1 to approximately 5 copies of SULT1A1 in individual samples: 5% of Caucasian subjects contained a single copy of the gene and 26% had three or more copies, while 63% of African-American subjects had three or more copies. Analysis of the genomic region surrounding the SULT1A1 gene in three separate cases with a deletion demonstrated that the entire SULT1A1 gene was affected. Reporter assays, constructed for each of the various 5'-FR SNP haplotypes, suggest that these may also play a role in SULT1A1 activity. However, the variability in the level of enzyme activity among 23 human platelet and 267 human liver samples was best explained by gene copy number differences when all sources of genetic variability were considered (P < 0.0001). Overall, these observations have obvious implications for the effectiveness of SULT1A1 as a drug and hormone metabolizing enzyme and its potential role as a risk factor for disease.
Variable sulfation of dietary polyphenols by recombinant human sulfotransferase (SULT) 1A1 genetic variants and SULT1E1
Human cytosolic sulfotransferases (SULTs) catalyze the sulfate conjugation of several important endo- and xenobiotics. Among the superfamily of SULT enzymes, SULT1A1 catalyzes the sulfation of small planar phenolic compounds, whereas SULT1E1 has a major role in estrogen conjugation. The human SULT1A1 gene has common single nucleotide polymorphisms that define three allozymes, SULT1A1*1, *2, and *3. The enzyme kinetics of SULT1A1 allozymes and SULT1E1 were characterized for the polyphenolic substrates apigenin, chrysin, epicatechin, quercetin, and resveratrol. Purified recombinant SULT proteins were generated in a baculoviral-insect cell system, and incubated in vitro with each substrate to determine catalytic activity. The effect of polyphenol sulfation was examined in mammalian cell lines stably expressing SULT1E1. For all polyphenols investigated, "normal-activity" SULT1A1*1 allozyme had significantly greater Vmax estimates than SULT1E1, and allele-specific differences in SULT1A1-mediated sulfation were observed. The polymorphic SULT1A1*2 allozyme exhibited low activity toward apigenin, epicatechin, and resveratrol. SULT1A1*1 and *3 acted as normal-activity allozymes for these substrates. Altered cellular proliferation was observed in MCF-7 cells stably expressing SULT1E1 upon treatment with chrysin, quercetin, or resveratrol, thus suggesting inactivation of these compounds by SULT1E1. These results suggest an important role for SULT isozymes and their pharmacogenetics in polyphenol disposition.
Sulfotransferase 1A1 (SULT1A1) polymorphism and susceptibility to primary brain tumors
Purpose: Sulfotransferase 1A1 is a member of sulfotransferase family that plays an important role in the biotransformation of numerous carcinogenic and mutagenic compounds through sulfation. The present study has investigated the association between SULT1A1 polymorphism and primary brain tumor incidence. Methods: SULT1A1 genotypes were successfully detected using the PCR-RFLP assay in 60 primary brain tumor patients and 156 hospital-based healthy control individuals with no history of cancer or precancerous disorder. Results: There was a significant difference in genotypes distribution (GG vs. GA + AA) between brain tumor patients (GG genotype frequency = 48.3%) and control population (GG genotype frequency = 65.4%; OR = 2.019, 95% CI = 1.103-3.695; P = 0.022). In order to determine the association between SULT1A1 polymorphism and specific types of brain tumors, the patients were classified according to the type of brain tumors they suffer from: glial and non-glial. Results of the statistical analyses of each group of patients in comparison with the control individuals showed a significant difference only between SULT1A1 polymorphism and non-glial brain tumors (OR = 2.615; 95% CI = 1.192-5.739; P = 0.014) but glial tumors (OR = 1.535; 95% CI = 0.688-3.425; P = 0.293). When non-glial tumors were classified as meningiomal and others (pituitary adenoma, craniopharyngioma, acoustic neuroma and hemangioblastoma), statistical analysis showed that this significance is only due to the meningiomal tumors (OR = 3.238; CI = 1.205-8.704; P = 0.015). We also estimated a reduced risk of brain tumor in non-smokers (OR = 1.700; CI = 0.800-3.615) in comparison to smokers (OR = 2.773; CI = 0.993-7.749), but this was not statistically significant. Conclusion: Our findings have suggested that there was a significant association between brain tumor and SULT1A1*2 allele (A allele that is also known as His allele) and this allele is an important risk factor in the development of meningiomal brain tumors.
Inhibitory effects of various beverages on human recombinant sulfotransferase isoforms SULT1A1 and SULT1A3
Sulfotransferase (SULT) 1A1 and SULT1A3 play important roles in the presystemic inactivation of beta(2) agonists in the liver and intestine, respectively. The study aimed to investigate the inhibitory effects of grapefruit juice, orange juice, green tea, black tea and oolong tea and their constituents on the activities of SULT1A1 and SULT1A3. The activities of both SULT1A1 and SULT1A3 were significantly inhibited by all the beverages investigated at a concentration of 10%. The beverage constituents were tested in concentration ranges considered to be physiologically relevant. The grapefruit constituent, quercetin, completely inhibited SULT1A1, while quercetin and naringin both partially inhibited SULT1A3. The orange constituents, tangeretin and nobiletin, also completely inhibited SULT1A1. The tea constituents, (-)-epicatechin gallate and (-)-epigallocatechin gallate, both almost completely inhibited SULT1A1 and SULT1A3. Moreover, the theaflavin and thearubigin fractions of black tea both completely inhibited SULT1A1 and strongly inhibited SULT1A3. The inhibitory action of green tea on SULT1A3 was competitive, while that of black tea and oolong tea was mixed competitive/non-competitive. Mechanism-based inhibition was not observed with any beverage. In conclusion, various beverages, especially teas, inhibit the function of SULT1A3, and therefore may have the potential to increase the bioavailability of orally administered substrates of SULT1A3, such as beta(2) agonists.
Role of ATP-sensitive potassium channels in the piracetam induced blockade of opioid effects
The present study has been designed to investigate the effect of piracetam on morphine/ buprenorphine-induced antinociception in rats and effect of piracetam on morphine or minoxidil induced relaxation in KCl-precontracted isolated rat aortic ring preparation. Nociceptive threshold was measured by the tail flick test in rats. The cumulative dose responses of morphine or minoxidil were recorded in KCl-precontracted isolated rat aortic ring preparation. Piracetam attenuated buprenorphine-induced antinociception in rats. Piracetam significantly reduced the morphine and minoxidil induced relaxation in KCl precontracted isolated rat aortic ring preparation suggesting that piracetam interferes with opioid receptor and ATP-sensitive potassium channel (KATP) opener mediated responses in vitro. Thus, it may be suggested that piracetam attenuates opioid effects by an opioid receptor-KATP channel linked mechanism.
Genetic polymorphism of sulfotransferase 1A1, cigarette smoking, hazardous chemical exposure and urothelial cancer risk in a Taiwanese population
Objectives: To investigate the association between genetic polymorphism of sulfotransferase1A1 (SULT1A1), cigarette smoking, hazardous chemical exposure and urothelial cancer risk in a Taiwanese population. Methods: In a hospital-based case-control study, a total of 300 urothelial cancer (UC) cases and 300 cancer-free controls frequency-matched by age and gender were recruited from September 1998 to December 2005. The SULT1A1 arginine213histidine (Arg213His) polymorphism was genotyped using a polymerase chain reaction-restriction fragment length polymorphism method. Results: We found that the significantly increased UC risks of ever smokers and heavy smokers (> or =28 pack-years) were 2.1 (95% confidence interval [CI] = 1.4-3.3) and 2.2 (95% CI = 1.3-3.6), respectively. An increased UC risk of 1.8 (95% CI = 0.8-3.8) was observed among individuals with more than one item of hazardous chemical exposure, but it was not statistically significant. Compared with study subjects carrying the SULT1A1 Arg/Arg genotype, those with SULT1A1 Arg/His or His/His genotypes have a significantly decreased UC risk (Odds ratio [OR] = 0.5, 95% CI = 0.3-0.8). Heavy smokers carrying the SULT1A1 Arg/Arg genotype have a significantly increased UC risk (OR = 5.2, 95% CI = 2.3-11.6). Individuals who had been exposed to more than one item of hazardous chemicals and who carried the SULT1A1 Arg/Arg genotype have a significantly increased UC risk (OR = 3.7, 95% CI = 1.4-9.7). The highest significant increased UC risk (OR = 16.1, 95% CI = 2.9-87.2) was observed among ever smokers with hazardous chemical exposure and the SULT1A1 Arg/Arg genotype. Conclusions: SULT1A1 Arg213His polymorphism is associated with the development of UC, especially among cigarette smokers exposed to hazardous chemicals.
CNVs of human genes and their implication in pharmacogenetics
Pharmacogenetics encompasses genetic variation with importance for drug response and adverse drug reactions with emphasis on drug transporters, drug metabolizing enzymes, and drug receptors. The highest penetrance with respect to drug action is generally observed for variability in genes encoding drug metabolizing enzymes, and gene copy number variations play a very important role in this respect. Alleles containing 0-13 active gene copies have been described, and this variation affects the clinical outcome of treatment for about 20-30% of all drugs. Gene copy number variation has also an influence on nicotine metabolism and detoxification by glutathione transferases and sulfotransferases. In the current overview we provide an update of the situation with emphasis on clinically important examples.
Sulfotransferase gene copy number variation: pharmacogenetics and function
Pharmacogenetics is the study of the role of inheritance in variation to drug response. Drug response phenotypes can vary from adverse drug reactions at one end of the spectrum to equally serious lack of the desired effect of drug therapy at the other. Many of the current important examples of pharmacogenetics involve inherited variation in drug metabolism. Sulfate conjugation catalyzed by cytosolic sulfotransferase (SULT) enzymes, particularly SULT1A1, is a major pathway for drug metabolism in humans. Pharmacogenetic studies of SULT1A1 began over a quarter of a century ago and have advanced from biochemical genetic experiments to include cDNA and gene cloning, gene resequencing, and functional studies of the effects of single nucleotide polymorphisms (SNPs). SNP genotyping, in turn, led to the discovery of functionally important copy number variations (CNVs) in the SULT1A1 gene. This review will briefly describe the evolution of our understanding of SULT1A1 pharmacogenetics and CNV, as well as challenges involved in utilizing both SNP and CNV data in an attempt to predict SULT1A1 function. SULT1A1 represents one example of the potential importance of CNV for the evolving disciplines of pharmacogenetics and pharmacogenomics.
SULT1A1 R213H polymorphism and breast cancer risk: a meta-analysis based on 8,454 cases and 11,800 controls
The SULT1A1 R213H polymorphism is suggested to be implicated in the development and progression of breast cancer. However, the published findings are inconsistent. We therefore performed a meta-analysis of 8,454 breast cancer cases and 11,800 controls from 14 published case-control studies. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association of the R213H polymorphism with breast cancer risk. Overall, our results suggested that there is no significant relationship between SULT1A1 R213H polymorphism and the risk of breast cancer. However, further ethnic population analysis revealed a significantly increased risk of breast cancer for HH allele carriers among Asians (for HH vs. RR: OR = 2.27, 95% CI = 1.11-4.63, P (heterogeneity) = 0.63; for the recessive model: OR = 2.03, 95% CI = 1.00-4.41, P (heterogeneity) = 0.62). Taken together, this meta-analysis suggests that the SULT1A1 R213H may be a low-penetrant risk factor for developing breast cancer in Asian population.
UGT2B17 and SULT1A1 gene copy number variation (CNV) detection by LabChip microfluidic technology
Background: Gene copy number variations (CNVs) are increasingly recognized to play important roles in the expression of genes and hence on their respective enzymatic activities. This has been demonstrated for a number of drug metabolizing genes, such as UDP-glucuronosyltransferases 2B17 (UGT2B17) and sulfotransferase 1A1 (SULT1A1), which are subject to genetic heterogeneity, including CNV. Quantitative assays to assess gene copy number are therefore becoming an integral part of accurate genotype assessment and phenotype prediction. Methods: In this study, we evaluated a microfluidics-based system, the Bio-Rad Experion system, to determine the power and utility of this platform to detect UGT2B17 and SULT1A1 CNV in DNA samples derived from blood and tissue. UGT2B17 is known to present with 0, 1 or 2 and SULT1A1 with up to 5 gene copies. Results: Distinct clustering (p<0.001) into copy number groups was achieved for both genes. DNA samples derived from blood exhibited less inter-run variability compared to DNA samples obtained from liver tissue. This variability may be caused by tissue-specific PCR inhibitors as it could be overcome by using DNA from another tissue, or after the DNA had undergone whole genome amplification. Conclusions: This method produced results comparable to those reported for other quantitative test platforms.
Effect of hormone metabolism genotypes on steroid hormone levels and menopausal symptoms in a prospective population-based cohort of women experiencing the menopausal transition
Objective: This study evaluated whether genes involved in the metabolism of steroid hormones are associated with hormone levels or menopausal symptoms. Methods: We used a population-based prospective sample of 436 African American (AA) and European American (EA) women who were premenopausal at enrollment and were followed longitudinally through menopause. We evaluated the relationship between steroid hormone metabolism genotypes at COMT, CYP1A2, CYP1B1, CYP3A4, CYP19, SULT1A1, and SULT1E1 with hormone levels and menopausal features. Results: In EA women, SULT1E1 variant carriers had lower levels of dehydroepiandrosterone sulfate, and SULT1A1 variant carriers had lower levels of estradiol, dehydroepiandrosterone sulfate, and testosterone compared with women who did not carry these variant alleles. In AA women, CYP1B1*3 genotypes were associated with hot flashes (odds ratio [OR], 0.62; 95% CI, 0.40-0.95). Interactions of CYP1A2 genotypes were associated with hot flashes across menopausal stage (P = 0.006). Interactions of CYP1B1*3 (P = 0.02) and CYP1B1*4 (P = 0.03) with menopausal stage were associated with depressive symptoms. In EA women, SULT1A1*3 was associated with depressive symptoms (OR, 0.53; 95% CI, 0.41-0.68) and hot flashes (OR, 2.08; 95% CI, 1.64-2.63). There were significant interactions between SULT1A1*3 and hot flashes (P < 0.001) and between SULT1A1*2 and depressive symptoms (P = 0.007) on menopausal stage, and there were race-specific effects of SULT1A1*2, SULT1A1*3, CYP1B1*3, and CYP3A4*1B on menopause. Conclusions: Our results suggest that genotypes are associated with the occurrence of menopause-related symptoms or the timing of the menopausal transition.
Functional genetic variants in the 3'-untranslated region of sulfotransferase isoform 1A1 (SULT1A1) and their effect on enzymatic activity
Sulfotransferase isoform 1A1 (SULT1A1) is the most highly expressed hepatic sulfotransferase and is involved in the biotransformation of a wide variety of endo- and xenobiotics. A common single nucleotide polymorphism (SNP) in the coding region of SULT1A1, several proximal promoter SNPs, and copy number variation (CNV) are associated with altered enzymatic activity, but these variants do not fully account for the observed variation of SULT1A1 activity in human populations. In order to identify additional SNPs modulating SULT1A1 activity, we examined the 3'-untranslated region (UTR) of SULT1A1 in 97 liver samples. Direct sequencing revealed that two SNPs in the 3'-UTR (902A > G [rs6839] and 973C > T [rs1042157]) and one SNP in the 3'-flanking region (1307G > A [rs4788068]) were common. These SNPs are in absolute linkage disequilibrium with each other and in tight linkage with SULT1A1 1/2 (linkage coefficient D' 0.83) and are significantly associated with SULT1A1 messenger RNA (p = 0.001, 0.029, 0.021) and enzymatic activity (p = 0.022, 0.012, 0.027). We then examined the collective effects of 3'-UTR SNPs, SULT1A1 1/2, and CNV on SULT1A1 activity in 498 Caucasian and 127 African-American subjects by haplotype analysis. This analysis revealed that SULT1A1 1/2 does not contribute to the variation in SULT1A1 enzymatic activity when the 3'-UTR SNPs are included in the statistical model. Two major haplotypes (ACG and GTA) were significantly correlated with SULT1A1 activity, and when stratified by copy number, the SULT1A1 3'-UTR SNPs remain significantly associated with SULT1A1 enzymatic activity in Caucasians, but not in African-Americans. Subsequent functional characterization revealed that a microRNA, miR-631, regulates SULT1A1 expression in a genotype-specific manner.
CYP2D6, SULT1A1 and UGT2B17 copy number variation: quantitative detection by multiplex PCR
Aim: Among the genes of drug-metabolizing enzymes, CYP2D6 is notoriously difficult to characterize owing to the complexity of gene deletions, duplications, multiplications and the presence of hybrid genes composed of CYP2D6 and CYP2D7. For SULT1A1 up to five gene copies have been reported, while UGT2B17 is known for gene deletions only. Different platforms exist for copy number variation (CNV) detection; however, there are no gold standards. Robust methods are required that address specific challenges to accurately determine gene CNVs in complex gene loci. Materials & methods: Quantitative multiplex PCR amplification (MPA) was performed on a diverse set of genomic DNA samples. Resulting PCR fragments were separated on an ABI 3730 instrument and analyzed with GeneMapper. CYP2D6 was targeted at four different gene regions and either normalized against CYP2D8 or UGT2B15 and SULT1A2. Inconsistent observations and CNVs contrasting genotype data were further characterized by long-range PCR and/or DNA sequence analysis. UGT2B17 and SULT1A1 were normalized against UGT2B15 and SULT1A2, respectively. Results: MPA detected 0-5, 1-5 and 0-2 copies for CYP2D6, SULT1A1 and UGT2B17, respectively. The interrogation of four CYP2D6 regions resulted in robust copy number assignments that were in agreement with genotype, sequencing and extra long PCR-based data. Gene deletions, duplication, and multiplications among known and novel hybrid genes were reliably identified. Novel findings regarding allelic variation include nonfunctional CYP2D6/2D7 hybrids such as CYP2D6*4N and *68, which were consistently identified on a subset of CYP2D6*4 alleles. In addition, a novel variant, designated CYP2D6*83, was discovered. For SULT1A1, we report the first six-copy case and for UGT2B15 and UGT2B17 we have evidence for rare deletion and duplication events, respectively. Conclusion: This MPA-based copy number platform not only allowed us to determine CNVs, but also served as a tool for allele discovery and characterization in a diverse panel of samples in a fast and reliable manner.
Minoxidil sulfate is the active metabolite that stimulates hair follicles
An important step in understanding minoxidil's mechanism of action on hair follicles was to determine the drug's active form. We used organ-cultured vibrissa follicles to test whether it is minoxidil or its sulfated metabolite, minoxidil sulfate, that stimulates hair growth. Follicles from neonatal mice were cultured with or without drugs and effects were assessed by measuring incorporation of radiolabeled cysteine in hair shafts of the treated follicles. Assays of minoxidil sulfotransferase activity indicated that vibrissae follicles metabolize minoxidil to minoxidil sulfate. Dose-response studies showed that minoxidil sulfate is 14 times more potent than minoxidil in stimulating cysteine incorporation in cultured follicles. Three drugs that block production of intrafollicular minoxidil sulfate were tested for their effects on drug-induced hair growth. Diethylcarbamazine proved to be a noncompetitive inhibitor of sulfotransferase and prevented hair growth stimulation by minoxidil but not by minoxidil sulfate. Inhibiting the formation of intracellular PAPS with chlorate also blocked the action of minoxidil but not of minoxidil sulfate. Acetaminophen, a potent sulfate scavenger blocked cysteine incorporation by minoxidil. It also blocked follicular stimulation by minoxidil sulfate apparently by directly removing the sulfate from the drug. Experiments with U-51,607, a potent minoxidil analog that also forms a sulfated metabolite, showed that its activity was inhibited by both chlorate and diethylcarbamazine. These studies show that sulfation is a critical step for hair-growth effects of minoxidil and that it is the sulfated metabolite that directly affects hair follicles.
SULT1A1 rs9282861 polymorphism-a potential modifier of efficacy of the systemic adjuvant therapy in breast cancer?
Background: Sulfotransferase 1A1 (SULT1A1) participates in the elimination of 4-hydroxy-tamoxifen (4-OH-TAM), which is one of the major active metabolites of tamoxifen (TAM). Homozygous SULT1A1 variant allele genotype has been associated with lower catalytic activity and thermostability of the enzyme. Previous clinical studies suggest that the SULT1A1 rs9282861 polymorphism may influence the survival of breast cancer patients treated with TAM in the adjuvant setting. We investigated the effect of rs9282861 genotypes on the survival of Finnish breast cancer patients treated with adjuvant chemotherapy or TAM. Methods: The rs9282861 genotypes of 412 Finnish breast cancer patients with early breast cancer were identified by using PCR-RFLP method. Seventy six patients were treated with adjuvant cyclophosphamide based chemotherapy only, 65 patients received adjuvant TAM, and four patients were treated with both adjuvant chemotherapy and TAM. Overall long-term survival (OS), breast cancer specific survival (BCSS), and relapse-free survival (RFS) by rs9282861 genotypes were evaluated by the Kaplan-Meier method and Cox regression analysis. Results: The multivariate analysis of 145 patients receiving either adjuvant TAM or chemotherapy showed a statistically significantly improved OS in patients with the rs9282861 homozygous variant AA genotype (hazard ratio [HR] = 0.50, 95% confidence interval [CI] = 0.29-0.88, P = 0.015). In the separate analyses of patients receiving only chemotherapy or adjuvant TAM, there were no statistically significant differences in survival. Conclusions: In this prospective study, we observed a previously unreported association between the SULT1A1 rs9282861 genotype and OS of breast cancer patients treated with adjuvant chemotherapy or TAM. This novel finding suggests that the rs9282861 polymorphism modifies the long-term clinical outcome of patients receiving adjuvant TAM or chemotherapy.
Modulation of the cochaperone AHA1 regulates heat-shock protein 90 and endothelial NO synthase activation by vascular endothelial growth factor
Objective: Vascular endothelial growth factor (VEGF) signaling to endothelial NO synthase (eNOS) plays a central role in angiogenesis. In endothelial cells (ECs), heat-shock protein 90 (Hsp90) is also a regulator of eNOS activity. Our study is designed to determine whether modulation of the activator of Hsp90 ATPase 1 (AHA1) regulates the function of Hsp90 in ECs. Methods and results: We show that eNOS phosphorylation on Ser-1179 after VEGF stimulation is significantly reduced in ECs transfected with a small interfering RNA against AHA1. Accordingly, VEGF-stimulated NO production, endothelial permeability, cell migration, and EC invasion in Matrigel implants in mice are reduced in small interfering RNA against AHA1-treated conditions. Furthermore, the induction of eNOS association with Hsp90 after VEGF stimulation is decreased in AHA1-downregulated cells. We also demonstrate that modulation of Hsp90 activity by AHA1 regulates phosphorylation of Hsp90 on Tyr-300. Interestingly, the association of AHA1 with Hsp90 is increased after c-Src-mediated phosphorylation of Hsp90 on Tyr-300. Finally, we show that overexpression of AHA1 in ECs promotes association of eNOS and Hsp90, phosphorylation of Ser-1179 of eNOS, increases NO production, and cell migration. Conclusions: These results reveal that modulation of Hsp90 activity by AHA1 regulates VEGF signaling to eNOS and angiogenesis.
Differential promoter activities of functional haplotypes in the 5'-flanking region of human sulfotransferase 1A1
Previously, we reported five common single nucleotide polymorphisms (SNPs), -624G>C, -396G>A, -358A>C, -341C>G, and -294T>C, and six common haplotypes (CGACT, GAACT, GGAGC, GGACC, CAACT, and GAACC) in the 5'-flanking region of the SULT1A1 gene that were associated with altered enzymatic activity. In the present study, we performed in vitro assays to determine the functional impact of these genetic variations on the promoter activity. Dual luciferase reporter assays revealed that these SNPs are located in a negative regulatory fragment of the SULT1A1 gene. Further experiments demonstrated that these SNPs and haplotypes affected promoter activities of SULT1A1. Electrophoretic mobility shift assays showed distinctive binding patterns for the SNPs -396G>A and -294T>C, due to differential binding affinities of the G/A alleles and the T/C alleles to nuclear proteins extracted from the liver carcinoma cell lines, HepG2 and Huh7.
SULT1A1 genetic polymorphisms and the association between smoking and oral cancer in a case-control study in Brazil
Introduction: Oral cancer is a public health problem worldwide, being tobacco and alcohol consumption their main risk factors. Sulfotransferase (SULT) 1A1 (encoded by SULT1A1) is involved in procarcinogens metabolism, such as polycyclic aromatic hydrocarbons (PAHs) present in tobacco smoke. Objective: The aim of this study was to explore the magnitude of association between SULT1A1 gene Arg(213)His polymorphism and oral cancer, and to explore the interaction between such polymorphism and smoking. Methods: A hospital-based case-control study was carried out in Rio de Janeiro, Brazil, during 1999-2002. Epidemiological data and biological samples were obtained from 202 oral cancer patients and 196 sex and age-frequency matched controls without cancer antecedents. Results: No association was observed between Arg(213)His SULT1A1 polymorphism and oral cancer risk in overall analysis (OR = 1.06, 95% CI = 0.71-1.57). The magnitude of association between cigarette smoking and oral cancer was higher in individuals with a SULT1A1(*)1 isoform (wild type, genotype Arg/Arg) (OR = 10.19, 95% CI = 3.90-26.61) than in those with at least one SULT1A1(*)2 allele (genotypes Arg/His + His/His) (OR = 4.50, 95% CI =2.09-9.69). Conclusion: Our results suggest that Arg(213)His SULT1A1 polymorphism may modulate the association between smoking and oral cancer. However, this association needs to be replicated in other studies: due to modest number of cases and controls, the role of chance in the observed association cannot be ruled out.
Copy number variation in sulfotransferase isoform 1A1 (SULT1A1) is significantly associated with enzymatic activity in Japanese subjects
Sulfotransferase isoform 1A1 (SULT1A1) plays a key role in the metabolism of a variety of endo- and xenobiotics and it's activity could influence response to drugs. Our previous studies have focused on the impact of genetic variants of SULT1A1 on enzymatic activity in Caucasians and African-Americans. However, the contribution of genetic variants to SULT1A1 activity in Asians has not been explored. In this study, we investigated the collective effects of both SULT1A1 copy number variants (CNVs) and single nucleotide polymorphisms (SNPs) in the promoter region, coding region, and 3' untranslated region on SULT1A1 activity in Japanese subjects. SNPs in the SULT1A1 promoter and 3' untranslated region were not associated with SULT1A1 activity (P > 0.05). SULT1A1*1/2 (Arg213His) was marginally associated with SULT1A1 activity (P = 0.037). However, SULT1A1 CNVs were strongly associated with SULT1A1 activity (trend test P = 0.008) and accounted for 10% of the observed variability in activity for Japanese subjects. In conclusion, SULT1A1 CNVs play a pivotal role in determination of SULT1A1 activity in Japanese subjects, highlighting the influence of ethnic differences in SULT1A1 genetic variants on drug metabolism and therapeutic efficacy.
Sulfation of minoxidil by human liver phenol sulfotransferase
The N,O-sulfate of minoxidil (Mnx) is the active agent in producing the vasodilation and the hair-growth stimulating responses observed with Mnx treatment. In this report, Mnx sulfation activity was assayed in cytosol prepared from several normal human livers, and Mnx sulfation was shown to correlate significantly with the activity of the phenol-sulfating form of phenol sulfotransferase (P-PST) activity in the same livers. No correlation was observed between Mnx sulfation and the dopamine or dehydroepiandrosterone (DHEA) sulfotransferase activities present in human liver. Mnx sulfation also copurified with P-PST activity during the purification of P-PST from human liver. During the purification procedure, Mnx and p-nitrophenol sulfotransferase (P-PST) activities were resolved from the dopamine and DHEA sulfation activities catalyzed by the monoamine-sulfating form of phenol sulfotransferase (M-PST) and DHEA sulfotransferase respectively. Also, purified DHEA sulfotransferase was not capable of sulfating Mnx, and no data were obtained to indicate that Mnx is a substrate for M-PST. p-Nitrophenol, a substrate for P-PST, was demonstrated to be a competitive inhibitor of Mnx sulfation catalyzed by purified P-PST when Mnx was the variable substrate. These results indicate that Mnx is sulfated and, therefore, bioactivated by P-PST in human liver.
Novel enzymatic assay predicts minoxidil response in the treatment of androgenetic alopecia
Topical minoxidil is the most common drug used for the treatment of androgenetic alopecia (AGA) in men and women. Although topical minoxidil exhibits a good safety profile, the efficacy in the overall population remains relatively low at 30-40%. To observe significant improvement in hair growth, minoxidil is typically used daily for a period of at least 3-4 months. Due to the significant time commitment and low response rate, a biomarker for predicting patient response prior to therapy would be advantageous. Minoxidil is converted in the scalp to its active form, minoxidil sulfate, by the sulfotransferase enzyme SULT1A1. We hypothesized that SULT1A1 enzyme activity in the hair follicle correlates with minoxidil response for the treatment of AGA. Our preliminary retrospective study of a SULT1A1 activity assay demonstrates 95% sensitivity and 73% specificity in predicting minoxidil treatment response for AGA. A larger prospective study is now under way to further validate this novel assay.
A pharmacogenetic survey of androgen receptor (CAG)n and (GGN)n polymorphisms in patients experiencing long term side effects after finasteride discontinuation
Finasteride is a steroid 5-alpha-reductase inhibitor, approved for the treatment of androgenetic alopecia (AGA) and benign prostate hyperplasia. In some patients the treatment is associated with adverse side effects that could become persistent after therapy discontinuation, resulting in the so-called post-finasteride syndrome (PFS). A pharmacogenetic component in the response to finasteride treatment was previously demonstrated. Two polymorphisms (CAG) rs4045402 and (GGN) rs3138869 in the gene encoding for the androgen receptor (AR) have been hypothesized to play a role in finasteride sensitivity. We aimed to compare the rs4045402 and rs3138869 polymorphisms prevalence in a group of 69 selected subjects (AGA+PFS) that used finasteride to treat alopecia and developed persistent side effects, with that in a group of 91 untreated subjects with AGA (AGA), and a group of 76 untreated subjects without AGA (NO-AGA). The rs4045402 and rs3138869 polymorphisms extreme-lengths alleles were more frequent among AGA+PFS (odds ratio, 5.88; 95% CI, 1.87-18.52) and AGA subjects (odds ratio, 3.55; 95% CI, 1.13-11.21) than among NO-AGA subjects, probably reflecting the genetic predisposing factors for AGA development. In conclusion, we described a predictive effect of the less common repeats' length CAG-rs4045402 and GGN-rs3138869 on AGA development. Prospective trials are required to confirm our findings also in other ethnicities, and to highlight possible further pharmacogenetic predictive markers of susceptibility to adverse effects.
Sulfotransferase SULT1A1 Arg213His polymorphism with cancer risk: a meta-analysis of 53 case-control studies
Background: The SULT1A1 Arg213His (rs9282861) polymorphism is reported to be associated with many kinds of cancer risk. However, the findings are conflicting. For better understanding this SNP site and cancer risk, we summarized available data and performed this meta-analysis. Methods: Data were collected from the following electronic databases: PubMed, Web of Knowledge and CNKI. The association was assessed by odd ratio (OR) and the corresponding 95% confidence interval (95% CI). Results: A total of 53 studies including 16733 cancer patients and 23334 controls based on the search criteria were analyzed. Overall, we found SULT1A1 Arg213His polymorphism can increase cancer risk under heterozygous (OR 1.09, 95% CI = 1.01-1.18, P = 0.040), dominant (OR = 1.10, 95% CI = 1.01-1.19, P = 0.021) and allelic (OR = 1.08, 95% CI = 1.02-1.16, P = 0.015) models. In subgroup analyses, significant associations were observed in upper aero digestive tract (UADT) cancer (heterozygous model: OR = 1.62, 95% CI = 1.11-2.35, P = 0.012; dominant model: OR = 1.63, 95% CI = 1.13-2.35, P = 0.009; allelic model: OR = 1.52, 95% CI = 1.10-2.11, P = 0.012) and Indians (recessive model: OR = 1.93, 95% CI = 1.22-3.07, P = 0.005) subgroups. Hospital based study also showed marginally significant association. In the breast cancer subgroup, ethnicity and publication year revealed by meta-regression analysis and one study found by sensitivity analysis were the main sources of heterogeneity. The association between SULT1A1 Arg213His and breast cancer risk was not significant. No publication bias was detected. Conclusions: The present meta-analysis suggests that SULT1A1 Arg213His polymorphism plays an important role in carcinogenesis, which may be a genetic factor affecting individual susceptibility to UADT cancer. SULT1A1 Arg213His didn't show any association with breast cancer, but the possible risk in Asian population needs further investigation.
Pharmacogenetics of SULT1A1
Cytosolic SULT1A1 participates in the bioconversion of a plethora of endogenous and xenobiotic substances. Genetic variation in this important enzyme such as SNPs can vary by ethnicity and have functional consequences on its activity. Most SULT1A1 genetic variability studies have been centered on the SULT1A1*1/2 SNP. Highlighted here are not only this SNP, but other genetic variants associated with SULT1A1 that could modify drug efficacy and xenobiotic metabolism. Some studies have investigated how differential metabolism of xenobiotic substances influences susceptibility to or protection from cancer in multiple sites. This review will focus primarily on the impact of SULT1A1 genetic variation on the response to anticancer therapeutic agents and subsequently how it relates to environmental and dietary exposure to both cancer-causing and cancer-preventative compounds.
Ethanol up-regulates phenol sulfotransferase (SULT1A1) and hydroxysteroid sulfotransferase (SULT2A1) in rat liver and intestine
Ethanol-consumption impairs physiological-efficiency/endurance, expedites senescence. Impaired-regulations of steroids/biomolecules link these processes. Steroids are catabolized by cytosolic-sulfotransferases (SULTs). Ethanol-induction of eukaryotic-SULTs-expression is scanty. Plant (Brassica-napus) steroid-sulfotransferase; BNST3/BNST4 (gene/BNST) is highly ethanol-inducible (protein/mRNA). Resembling mammalian-SULTs catalytic-mechanism BNSTs show broad substrate-specificities (mammalian-steroids; estradiol/dehydroepiandrosterone/pregnanolone). Recently, ethanol-regulation of SULTs-expression is verified in rat liver/intestine/cultured human-hepatocarcinoma (Hep-G2) cells at enzyme-activity/protein-expression (Western-blot) level. Here, two week's ethanol ingestion by male rat significantly increased SULT2A1 in their liver/intestine (p < 0.05-p < 0.001) and phenol-sulfotransferase (SULT1A1) in intestine (p < 0.001) at enzyme-activity/protein levels. In human cells, ethanol significantly (2-fold) increased hSULT1A1/hSULT1E (2-3 fold) protein expressions paralleling their enzymatic-activities (p < 0.05-p < 0.01). The earlier finding of alcohol-association to the physiological impairment may be corroborated by our present findings. Inductions of SULT-expressions by ethanol have significant physiological/pharmacological consequences.
Response to Microneedling Treatment in Men with Androgenetic Alopecia Who Failed to Respond to Conventional Therapy
Introduction: The efficacy of conventional therapy viz. finasteride and minoxidil in androgenetic alopecia (AGA) that is based on both preventing hair loss and promoting new hair growth, varies between 30% and 60%. This has led to a large number of patients unsatisfied who demand for a better cosmetic coverage over the scalp. Microneedling has recently been reported to be promising, effective and a safe treatment modality in the treatment of AGA. This augments the response of conventional therapy. Materials and methods: Four men with AGA were on finasteride and 5% minoxidil solution since 2 to 5 years. Though there was no worsening in their respective AGA stages with the therapy, they showed no new hair growth. They were subjected to microneedling procedure over a period of 6 months along with their ongoing therapy. Patients were assessed with the use of the standardized 7-point evaluation scale and patients' subjective hair growth assessment scale. The patients were followed up for 18 months post microneedling procedure to assess the sustainability of the response. Results: All patients showed a response of + 2 to + 3 on standardized 7-point evaluation scale. The response in the form of new hair growth started after 8-10 sessions. The patients' satisfaction was more than 75% in three patients and more 50% in one patient, on patients' subjective hair growth assessment scale. The obtained results were sustained post procedure during 18 months follow-up period. Conclusion: Treatment with microneedling showed an accelerated response with addition of microneedling procedure leading to significant scalp density. This is the first case series to report the boosting effect of microneedling with respect to new hair follicle stimulation in patients with androgenetic alopecia who were poor responders to conventional therapy.
Sulfotransferase 1A1 as a Biomarker for Susceptibility to Carcinogenesis: From Molecular Genetics to the Role of Dietary Flavonoids
Background: Sulfotransferase (SULT) 1A1 is a phase II metabolic enzyme that catalyzes sulfate conjugation of various phenolic compounds, including endogenous substances, such as estrogens and thyroid hormones, but also different xenobiotics. Although sulfation is classically considered as a detoxification event facilitating the excretion of more water soluble metabolites from the body, in some cases such bioconversion may also lead to bioactivation of promutagens, producing highly reactive intermediates which are capable of damaging DNA and promoting carcinogenesis. The most common polymorphism in SULT1A1 (Arg213His) has an important functional impact by affecting the capacity to sulfate diverse substrates and numerous case-control studies have shown associations between SULT1A1 variants and susceptibility to different malignancies. Several factors may significantly influence such relationships, including ethnicity, gender, parity, menopausal status, use of estrogen replacement therapy, exposure to tobacco smoke or occupational chemicals. Results and conclusion: In this review article, we show that one more important determinant should be considered as a stratifying factor in studies of possible associations between SULT1A1 variants and cancer risk, i.e., the dietary intake of different flavonoids. As sulfation of bioactive plant polyphenols can change their potential anticancer activities and, on the other hand, these phytochemicals are capable to behave also as potent SULT1A1 inhibitors, the regular dietary exposure of humans to these compounds can make a great contribution to the impact of sulfation capacity on individual susceptibility to carcinogenesis. The effect of specific flavonoids as well as their interactions with other factors on associations between SULT1A1 alleles and cancer risk certainly needs further thorough studies.
Influence of SULT1A1 genetic variation on age at menopause, estrogen levels, and response to hormone therapy in recently postmenopausal white women
Objective: Onset and symptoms of menopause, and response to hormone therapy (HT) show large interindividual variability. SULT1A1 encodes for a highly expressed enzyme that metabolizes estrogens. We evaluated the relationship between genetic variation in SULT1A1, menopause age, symptoms, and response to HT. Methods: Women enrolled in the Kronos Early Estrogen Prevention Study at Mayo Clinic were randomized to 48 months of treatment with oral conjugated equine estrogen (n = 34), transdermal 17β-estradiol (E2) (n = 33), or placebo (n = 35). Linear regression models and ANOVA were used to test for association of SULT1A1 copy number, rs3760091, rs750155, and rs9282861 (SULT1A12), with age at menopause and symptoms, levels of estrogens (estrone [E1], estrone sulfate [E1S], E2, and estradiol sulfate [E2S]), before and after HT. Results: SULT1A1 gene copy number affected the minor allele frequency for each single nucleotide polymorphisms tested. Before administration of exogenous hormones, increasing number of G alleles at rs9282861 was associated with earlier age at menopause (P = 0.014), lower frequency of night sweats (P = 0.009), and less severe insomnia (P = 0.046). After 48 months of treatment, SULT1A1 genotype was not associated with the presence of menopausal symptoms. In women randomized to oral conjugated equine estrogen, increasing number of the A allele at rs750155 was associated with lower E1S and E2S (P = 0.004 and 0.017), whereas increasing number of the C allele at rs3760091 was associated with lower E2S/E2 (P = 0.044). Conclusions: Interindividual variability in onset of menopause and symptoms before initiation of HT is explained in part by genetic variation in SULT1A1 and may represent a step toward individualizing HT treatment decisions.
Androgen Receptor (AR) Gene (CAG)n and (GGN)n Length Polymorphisms and Symptoms in Young Males With Long-Lasting Adverse Effects After Finasteride Use Against Androgenic Alopecia
Introduction: Long-term adverse symptoms of men who used oral finasteride against androgenic alopecia have been recently described as post-finasteride syndrome (PFS). Aim: To determine whether (CAG)n-rs4045402 and (GGN)n-rs3138869 polymorphisms in the androgen receptor (AR) gene are implicated in PFS. Methods: AR polymorphisms were studied according to PFS symptoms in 66 white participants (31.8% Italian, 28.8% American, and 39.4% other). Main outcome measures: Symptoms were investigated by an ad hoc 100-item questionnaire and the Arizona Sexual Experience Scale and Aging Male Symptom Scale (AMS). (CAG)n and (GGN)n repeats were categorized as short ([CAG]9-19, [GGN]<23), medium ([CAG]20-24, [GGN]23), or long ([CAG]25-37, [GGN]>23). Results: Median age was 32 years, duration of finasteride use was 360 days, and time from finasteride discontinuation was 1,053 days. We observed several frequency differences in symptoms according to (CAG)n and (GGN)n repeat numbers. Three AMS items were worse for medium (GGN)23 than for long (GGN)>23 carriers and one item was worse for short (GGN)<23 carriers. The AMS item for decrease in sexual desire or libido was worse for short (CAG)9-19 carriers than for medium (CAG)20-24 carriers. Through the ad hoc questionnaire, significant findings in (CAG)n and/or (GGN)n repeats were obtained for penile discomfort, loss of scrotal sensitivity, scrotal discomfort, less pubic hair, loss of perceived perineal fullness, increased sperm density, involuntary muscle spasms, loss of muscle tone, increased weight (>2 kg), increased skin dryness, and onset of symptoms after finasteride use. Conclusion: This study showed that short and/or long (CAG)n and (GGN)n repeats had different frequencies according to symptoms reported by patients with PFS, likely reflecting the vast array of genes modulated by the AR. This study showed a U-curvilinear profile of (CAG)n repeats for skin dryness symptoms, where the two extremes exhibited a worse condition than medium repeats. Further studies are necessary to investigate the PFS pathophysiology using a precision medicine approach.
The number of CAG and GGN triplet repeats in the Androgen Receptor gene exert combinatorial effect on hormonal and sperm parameters in young men
Androgen receptor (AR) is a transcription factor that is activated upon binding to testosterone (T) and is implicated in regulating the expression of reproduction-related genes. The human AR gene (Xq11-12) spans 186,588 bp and eight exons. N-terminal transactivation domain of the encoded AR protein harbours two polymorphic stretches of identical amino acids, a polyglutamine tract (encoded by 8-37 CAG-repeats) and a polyglycine tract (encoded by 10-30 GGN-repeats). We set forward to analyse independent and combinatory effects of the length of these repetitive tracts on male reproductive hormones, testicular and sperm parameters in a population-based cohort of Baltic young men (n = 974; aged 20.1 ± 2.1 years). We designed an assay to amplify and detect simultaneously the variants of both polymorphic repeats. The study revealed that elongated AR CAG tract was associated with lower FSH (linear regression: p = 0.0002, effect per repeat -0.056 IU/L). As a novel finding, the carriers of GGN-stretch with ≥24 repeats showed a trend for decreased sperm concentration (p = 0.027). Although neither of the variants exhibited an isolated effect on circulating T, their allelic combinations modulated serum T levels, as well as sperm concentration. The lowest T was measured for men carrying the AR gene with long CAG (n ≥ 25) and short GGN (n ≤ 21) repeat tracts (mean 18.8 vs. 25.5-28.6 nmol/L for the other AR variants, p = 0.017). The lowest sperm concentration was detected among individuals with both elongated repetitive stretches (CAG, n ≥ 25 and GGN, n ≥ 24; mean 49.0 vs. 68.4-72.1 mill/mL for the other variants; p = 0.00059). The innovative study design enabled to clearly demonstrate a combinatory impact of CAG and GGN repeat lengths at male reproductive parameters. As AR regulates transcription of over 900 genes in many tissues and organs, the combinatory effects of these common repeat-length variants on male physiology in the wider context and across lifetime are still to be assessed.
A Comparative Study of Microneedling with Platelet-rich Plasma Plus Topical Minoxidil (5%) and Topical Minoxidil (5%) Alone in Androgenetic Alopecia
Context: There are very few studies evaluating efficacy of platelet-rich plasma (PRP) in hair restoration and its combination with microneedling. As far as ascertained, there is no study to evaluate efficacy of microneedling with PRP plus topical minoxidil (5%) versus topical minoxidil (5%) alone in androgenetic alopecia (AGA). Aims: This study aims (1) to compare the efficacy of (a) topical minoxidil (5%) alone and (b) topical minoxidil (5%) + microneedling with PRP in men between 18 and 50 years with AGA Grade III to V vertex (Norwood-Hamilton scale) and (2) to perform objective and subjective evaluation based on clinical improvement and photographic evidence. Settings and design: The study was conducted in the outpatient department of dermatology, venereology, and leprology in tertiary care hospital. It was open, prospective study. Subjects and methods: Fifty patients with AGA were selected on the basis of inclusion and exclusion criteria. These patients were randomly divided into two groups of 25 patients each and were given following treatment: (i) Group A: topical minoxidil (5%) alone and (ii) Group B: topical minoxidil (5%) + microneedling with platelet-rich plasma (PRP). Statistical analysis used: Patients were assessed before starting the treatment and at the end of 6 months on the basis of (a) Patient's self-assessment based on standardized seven-point scale compared with baseline (b) Physician's assessment based on standardized seven-point scale of hair growth compared with baseline. Results: There was a significant improvement (P < 0.05) in both patients' assessment and investigator's assessment in Group B as compared to Group A at the end of 6 months. Conclusions: Microneedling with PRP is safe, effective, and a promising tool for the management of AGA.
Relationship of SULT1A1 copy number variation with estrogen metabolism and human health
Human cytosolic sulfotransferase 1A1 (SULT1A1) is considered to be one of the most important SULT isoforms for metabolism, detoxification, and carcinogenesis. This theory is driven by observations that SULT1A1 is widely expressed in multiple tissues and acts on a wide range of phenolic substrates. SULT1A1 is subject to functional common copy number variation (CNV) including deletions or duplications. However, it is less clear how SULT1A1 CNV impacts health and disease. To better understand the biological role of SULT1A1 in human health, we genotyped CNV in 14,275 Marshfield Clinic patients linked to an extensive electronic health record. Since SULT1A1 is linked to steroid metabolism, select serum steroid hormones were measured in 100 individuals with a wide spectrum of SULT1A1 CNV genotypes. Furthermore, comprehensive phenome-wide association studies (PheWAS) were conducted using diagnostic codes and clinical text data. For the first time, individuals homozygous null for SULT1A1 were identified in a human population. Thirty-six percent of the population carried >2 copies of SULT1A1 whereas 4% had ≤1 copy. Results indicate SULT1A1 CNV was negatively correlated with estrone-sulfate to estrone ratio predominantly in males (E1S/E1; p=0.03, r=-0.21) and may be associated with increased risk for common allergies. The effect of SULT1A1 CNV on circulating estrogen metabolites was opposite to the predicted CNV-metabolite trend based on enzymatic function. This finding, and the potential association with common allergies reported herein, warrants future studies.
SULT1A1 copy number variation: ethnic distribution analysis in an Indian population
Cytosolic sulfotransferases (SULTs) are phase II detoxification enzymes involved in metabolism of numerous xenobiotics, drugs and endogenous compounds. Interindividual variation in sulfonation capacity is important for determining an individual's response to xenobiotics. SNPs in SULTs, mainly SULT1A1 have been associated with cancer risk and also with response to therapeutic agents. Copy number variation (CNVs) in SULT1A1 is found to be correlated with altered enzyme activity. This short report primarily focuses on CNV in SULT1A1 and its distribution among different ethnic populations around the globe. Frequency distribution of SULT1A1 copy number (CN) in 157 healthy Indian individuals was assessed using florescent-based quantitative PCR assay. A range of 1 to >4 copies, with a frequency of SULT1A1 CN =2 (64.9%) the highest, was observed in our (Indian) population. Upon comparative analysis of frequency distribution of SULT1A1 CN among diverse population groups, a statistically significant difference was observed between Indians (our data) and African-American (AA) (p = 0.0001) and South African (Tswana) (p < 0.0001) populations. Distribution of CNV in the Indian population was found to be similar to that in European-derived populations of American and Japanese. CNV of SULT1A1 varies significantly among world populations and may be one of the determinants of health and diseases.
Association between SULT1A1 Arg213His (rs9282861) Polymorphism and Risk of Breast Cancer: A Systematic Review and Meta-Analysis
Background: The Arg213His (rs9282861) polymorphism of Sulfotransferase Family 1A Member 1 (SULT1A1) gene has been associated with risk of breast cancer in some epidemiological studies. Therefore, this systematic review and meta-analysis was conducted to evaluate the association of SULT1A1 Arg213His (rs9282861) polymorphism with susceptibility to breast cancer. Study design: A systematic review and meta-analysis. Methods: A comprehensive literature search for eligible studies was conducted in PubMed, Elsevier, Science Direct, Scopus and Google Scholar databases up to Oct 5, 2017. Pooled odds ratios (ORs) with their corresponding 95% confidence intervals (95% CIs) were used to evaluate the strength of the association using fixed effects models and random effects models. Results: Twenty relevant case-control studies involving 11077 cases and 14798 controls were included in this meta-analysis. Overall, there was a significant association between the SULT1A1 Arg213His (rs9282861) polymorphism and risk of breast cancer in the allele mode (A vs. G: OR=1.117, 95% CI: 1.011, 1.233, P=0.029) and the homozygote model (AA vs. GG: OR=1.288, 95% CI: 1.036, 1.601, P=0.022). Subgroup analysis based on ethnicity suggested SULT1A1 Arg213His (rs9282861) polymorphism had a subtly increased breast cancer risk among Asian population, but not Caucasians. Further, subgroup analyses, significant associations were observed in hospital-based group, RFLP-PCR group, and high-quality studies subgroups. Conclusions: SULT1A1 Arg213His (rs9282861) polymorphism might be associated with breast cancer risk, especially among Asian population. Moreover, the SULT1A1 Arg213His polymorphism is of high clinical relevance by ethnicity and would be a useful marker to identify patients who are at higher risk for breast cancer.
Mechanism of action of minoxidil in the treatment of androgenetic alopecia is likely mediated by mitochondrial adenosine triphosphate synthase-induced stem cell differentiation
Topical minoxidil is the only topical drug approved by the US Food and Drug Administration (FDA) for the treatment of androgenetic alopecia. However, the exact mechanism by which minoxidil stimulates anagen phase and promotes hair growth is not fully understood. In the late telegen phase of the hair follicle growth cycle, stem cells located in the bulge region differentiate and re-enter anagen phase, a period of growth lasting 2-6 years. In androgenetic alopecia, the anagen phase is shortened and a progressive miniaturization of hair follicles occurs, eventually leading to hair loss. Several studies have demonstrated that minoxidil increases the amount of intracellular Ca2+, which has been shown to up-regulate the enzyme adenosine triphosphate (ATP) synthase. A recent study demonstrated that ATP synthase, independent of its role in ATP synthesis, promotes stem cell differentiation. As such, we propose that minoxidil induced Ca2+ influx can increase stem cell differentiation and may be a key factor in the mechanism by which minoxidil facilitates hair growth. Based on our theory, we provide a roadmap for the development of a new class of drugs for the treatment of androgenetic alopecia.
Multi-ethnic SULT1A1 copy number profiling with multiplex ligation-dependent probe amplification
Aim: To develop a SULT1A1 multiplex ligation-dependent probe amplification assay and to investigate multi-ethnic copy number variant frequencies. Methods: A novel multiplex ligation-dependent probe amplification assay was developed and tested on 472 African-American, Asian, Caucasian, Hispanic and Ashkenazi Jewish individuals. Results: The frequencies of atypical total copy number (i.e., greater or less than two) were 38.7% for Hispanics, 38.9% for Ashkenazi Jewish, 43.2% for Caucasians, 53.6% for Asians and 64.1% for African-Americans. Heterozygous SULT1A1 deletion carriers (slow sulfators) were most common among Caucasians (8.4%), whereas African-Americans had the highest frequencies of three or more copies (rapid sulfators; 60.9%). Conclusion: Different ethnic and racial populations have varying degrees of SULT1A1-mediated sulfation activity, which warrants further research and that may have utility for drug response prediction among SULT1A1-metabolized medications.
The effect of topical minoxidil treatment on follicular sulfotransferase enzymatic activity
Minoxidil is the only US FDA-approved topical drug for the treatment of female and male pattern hair loss. Previously, it was demonstrated that topical minoxidil is metabolized to its active metabolite, minoxidil sulfate, by sulfotransferase enzymes located in the outer root sheath of hair follicles. The expression of sulfotransferase in the scalp varies greatly between individuals, and this difference in expression explains the varied response to minoxidil treatment. Previously, we have demonstrated the clinical utility of detecting sulfotransferase in plucked hair follicles to predict minoxidil response in pattern hair loss patients. Typically, exogenous exposure to substrates affects the expression of the enzymatic system responsible for their metabolism. For example, Phase I metabolizing enzymes, such as the cytochrome P450 family of enzymes, are known to be up-regulated in the presence of xenobiotic substrates. However, it is not known if Phase II metabolizing enzymes, such as the sulfotransferase family of enzymes, are similarly affected by the presence of substrates. In this study, we recruited 120 subjects and analyzed their sulfotransferase enzymatic activity before and after treatment with topical minoxidil. Adjusting the results for biologic (within subject) variability, we discovered that the sulfotransferase enzymatic system expression is stable over the course of minoxidil treatment. To the best of our knowledge, this is the first study to demonstrate the stability of sulfotransferase, a Phase II metabolizing enzyme, over the course of minoxidil treatment.
Genetic polymorphisms of 3'-untranslated region of SULT1A1 and their impact on tamoxifen metabolism and efficacy
Purpose: Tamoxifen has a wide inter-variability. Recently, two SNPs in the 3'-untranslated region (UTR) of the SULT1A1 gene, rs6839 and rs1042157, have been associated with decreased SULT1A1 activity. The aim of this study is to investigate the role of the rs6839 and rs1042157 on tamoxifen metabolism and relapse-free survival (RFS) in women diagnosed with early-breast cancer receiving tamoxifen. Methods: Samples from 667 patients collected in the CYPTAM study (NTR1509) were used for genotyping (CYP2D6, SULT1A1 rs6839 and rs1042157) and measurements of tamoxifen and metabolites. Patients were categorized in three groups depending on the decreased SULT1A1 activity due to rs6839 and rs1042157: low activity group (rs6839 (GG) and rs1042157 (TT)); high activity group (rs6839 (AA) and rs1042157 (CC)); and medium activity group (all the other combinations of rs6839 and rs1042157). Associations between SULT1A1 phenotypes and clinical outcome (RFS) were explored. Results: In the low SULT1A1 activity group, higher endoxifen and 4-hydroxy-tamoxifen concentrations were found, compared to the medium and high activity group (endoxifen: 31.23 vs. 30.51 vs. 27.00, p value: 0.016; 4-hydroxy-tamoxifen: 5.55 vs. 5.27 vs. 4.94, p value:0.05). In terms of relapse, the low activity group had a borderline better outcome compared to the medium and high SULT1A1 activity group (adjusted Hazard ratio: 0.297; 95% CI 0.088-1.000; p value: 0.05). Conclusion: Our results suggested that rs6839 and rs1042157 SNPs have a minor effect on the concentrations and metabolic ratios of tamoxifen and its metabolites, and RFS in women receiving adjuvant tamoxifen.
Low-dose daily aspirin reduces topical minoxidil efficacy in androgenetic alopecia patients
Topical minoxidil is the only US FDA approved OTC drug for the treatment of androgenetic alopecia (AGA). Minoxidil is a pro-drug converted into its active form, minoxidil sulfate, by the sulfotransferase enzymes in the outer root sheath of hair follicles. Previously, we demonstrated that sulfotransferase activity in hair follicles predicts response to topical minoxidil in the treatment of AGA. In the human liver, sulfotransferase activity is significantly inhibited by salicylic acid. Low-dose OTC aspirin (75-81 mg), a derivative of salicylic acid, is used by millions of people daily for the prevention of coronary heart disease and cancer. It is not known whether oral aspirin inhibits sulfotransferase activity in hair follicles, potentially affecting minoxidil response in AGA patients. In the present study, we determined the follicular sulfotransferase enzymatic activity following 14 days of oral aspirin administration. In our cohort of 24 subjects, 50% were initially predicted to be responders to minoxidil. However, following 14 days of aspirin administration, only 27% of the subjects were predicted to respond to topical minoxidil. To the best of our knowledge, this is the first study to report the effect of low-dose daily aspirin use on the efficacy of topical minoxidil.
Serum Levels of Androgen-Associated Hormones Are Correlated with Curative Effect in Androgenic Alopecia in Young Men
BACKGROUND Androgenic alopecia (AGA) is the most common type of hair loss in men. However, the pathogenesis is not yet fully understood and therapeutic approaches are limited. This retrospective study investigated the association between levels of androgen-associated hormones and curative effect in androgenic alopecia in young male AGA patients. MATERIAL AND METHODS By using chemiluminescence immunoassay, serum levels of androgens and upstream regulated hormones were measured in 178 young male patients with AGA and in 61 normal controls before therapy, 1 and 2 weeks after administration of finasteride. RESULTS Before oral finasteride therapy, we found significantly higher levels of serum free testosterone (FT) and dihydrotestosterone (DHT) in AGA patients than in normal controls. The levels of serum sex hormone-binding globulin (SHBG), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were similar in the 2 groups. There were no significant differences in serum androgen levels, including DHT and FT, among AGA patients with different grades of hair loss severity (p>0.05). After finasteride therapy, the levels of DHT decreased significantly (p<0.05). Increased serum levels of LSH or LH were also observed in 55 patients after therapy (p<0.05). The levels of SHGB did not change significantly after therapy (p>0.05). Patients with lower levels of serum FT and DHT than before who accepted finasteride therapy had a higher ratio of curative effect manifested by improved severity grade (p<0.05). Patients with higher levels of LSH or LH had a lower curative rate compared to those without change after therapy (p<0.05). CONCLUSIONS We confirmed the role of the androgens hypothalamus-hypophysis-sexual gland axis in the pathogenesis of AGA and the treatment effect of oral anti-androgen therapy in young male Chinese patients.
A Randomized Controlled, Single-Observer Blinded Study to Determine the Efficacy of Topical Minoxidil plus Microneedling versus Topical Minoxidil Alone in the Treatment of Androgenetic Alopecia
Background: Androgenetic alopecia (AGA) is the most common form of hair loss in adults, which is generally progressive in the absence of treatment. As a head full of healthy hair adds to the cosmetic appeal of the individual, the consequences of AGA are predominantly psychological. Currently, topical minoxidil is the first-line treatment for AGA. Many adjuvant treatment modalities have been used synergistically with minoxidil. Microneedling is one among such adjuvant treatments, which works by various mechanisms to stimulate the dermal papillary cells that play a key role in hair growth. Aim: To compare the efficacy of microneedling along with topical minoxidil and topical minoxidil alone in the treatment of AGA in men. Materials and methods: Sixty-eight men with Norwood-Hamilton grade III and IV AGA were recruited for the study. After randomization, one group was treated with weekly microneedling and twice daily application of 5% minoxidil solution and the other group was treated with twice daily application of 5% minoxidil solution alone. Global photographs were taken at baseline (pretreatment) and at end of the study duration. Trichoscopic images were taken from a targeted fixed area before treatment (baseline) and at end of the therapy from where hair count was also carried out. The two primary efficacy parameters were assessed: increase in the hair count from that of the baseline and patient self-assessment of hair growth at the end of the study. Results: The mean increase in hair count in the targeted area of one square inch at the end of the treatment was significantly greater for the combination treatment group (12.52/inch2) compared to that for the minoxidil alone group (1.89/inch2). Four patients in the "microneedling plus topical minoxidil" group reported a 50% improvement versus none in the "minoxidil alone" group. Conclusion: Our study showed that the combination of microneedling and topical minoxidil treatment was superior compared to topical minoxidil alone with regard to increase in the hair count and patient satisfaction, although the response achieved was not cosmetically significant.
Tretinoin enhances minoxidil response in androgenetic alopecia patients by upregulating follicular sulfotransferase enzymes
Minoxidil sulfate is the active metabolite required to exert the vasodilatory and hair growing effects of minoxidil. For hair growth, sulfotransferase enzymes expressed in outer root sheath of the hair follicle sulfonate minoxidil. The large intra-subject variability in follicular sulfotransferase was found to predict minoxidil response and thus explain the low response rate to topical minoxidil in the treatment of androgenetic alopecia. A method to increase minoxidil response would be of significant clinical utility. Retinoids have been reported to increase minoxidil response. The purported mechanism of action was retinoid modulation of skin permeation to minoxidil; however, evidence to the contrary supports retinoids increase dermal thickness. In order to elucidate the effect of topical retinoids on minoxidil response, we studied the effect of topical tretinoin on follicular sulfotransferase. In this study, we demonstrate that topical tretinoin application influences the expression of follicular sulfotransferase. Of clinical significance, in our cohort, 43% of subjects initially predicted to be nonresponders to minoxidil were converted to responders following 5 days of topical tretinoin application. To the best of our knowledge, this is the first study to elucidate the interaction mechanism between topical minoxidil and retinoids and thus provides a pathway for the development of future androgenetic alopecia treatments.
A Study to Compare the Efficacy of Platelet-rich Plasma and Minoxidil Therapy for the Treatment of Androgenetic Alopecia
Background: Androgenetic alopecia (AGA) is the most common cause of hair loss in men with limited treatment options. Platelet-rich plasma (PRP) therapy is one of the newer treatment options in the management of AGA which has shown promising results. Aims and objectives: This study was aimed at comparing the clinical efficacy of PRP therapy with minoxidil therapy. Materials and methods: In the study, patients were randomized into two groups - Group A (given PRP therapy) and Group B (given minoxidil therapy). Both groups were followed up over a period of 6 months, and final analysis was done with the help of global photography, hair pull test, standardized hair growth questionnaire, patient satisfaction score; in addition, a comparison of platelet counts in PRP was done, to know that if a clinical correlation exists between platelet concentration and clinical improvement. A total of 40 patients clinically diagnosed with AGA were enrolled in the study with 20 patients in each group. Four patients from Group A (PRP) and six patients from Group B (minoxidil) could not complete the treatment for 6 months and were eventually excluded. Results: At the end of 6 months, 30 patients were evaluated to compare the efficacy of intradermal PRP and topical minoxidil therapy. On global photography, Group A (PRP) was found to have a comparatively better outcome than Group B (minoxidil). In hair pull test, hair growth questionnaire, and patient satisfaction score, Group A was found to be better than Group B. Mean platelet count at baseline was 3.07 ± 0.5 lac/mm, 3 while platelet count in final PRP prepared was 12.4 ± 1.7 lac/mm, and patients with a higher platelet count in PRP had a much better clinical improvement compared to patients with a low platelet count in PRP. Side effects with PRP therapy were minimal with better results which may improve the compliance of the patient. Conclusion: PRP therapy can be a valuable alternative to topical minoxidil therapy in the treatment of AGA.
Oral minoxidil bio-activation by hair follicle outer root sheath cell sulfotransferase enzymes predicts clinical efficacy in female pattern hair loss
Structural and Dynamic Characterizations Highlight the Deleterious Role of SULT1A1 R213H Polymorphism in Substrate Binding
Sulfotransferase 1A1 (SULT1A1) is responsible for catalyzing various types of endogenous and exogenous compounds. Accumulating data indicates that the polymorphism rs9282861 (R213H) is responsible for inefficient enzymatic activity and associated with cancer progression. To characterize the detailed functional consequences of this mutation behind the loss-of-function of SULT1A1, the present study deployed molecular dynamics simulation to get insights into changes in the conformation and binding energy. The dynamics scenario of SULT1A1 in both wild and mutated types as well as with and without ligand showed that R213H induced local conformational changes, especially in the substrate-binding loop rather than impairing overall stability of the protein structure. The higher conformational changes were observed in the loop3 (residues, 235-263), turning loop conformation to A-helix and B-bridge, which ultimately disrupted the plasticity of the active site. This alteration reduced the binding site volume and hydrophobicity to decrease the binding affinity of the enzyme to substrates, which was highlighted by the MM-PBSA binding energy analysis. These findings highlight the key insights of structural consequences caused by R213H mutation, which would enrich the understanding regarding the role of SULT1A1 mutation in cancer development and also xenobiotics management to individuals in the different treatment stages.
The effect of GGC and CAG repeat polymorphisms on the androgen receptor gene in response to finasteride therapy in men with androgenetic alopecia
Background: It should be assessed whether the polymorphisms on androgen receptor gene can affect therapeutic response to androgenetic alopecia (AGA) medications. We aimed to find a link between polymorphisms on the androgen receptor gene (including the number of triple sequences of cytosine, adenine, and guanine [CAG] and guanine-guanine-cytosine [GGC]) and response to treatment with finasteride in male patients. Materials and methods: This case-control study was performed on 25 consecutive male patients with hereditary AGA and 25 sex-matched healthy individuals without AGA. The complete sequence of the gene was extracted from the NCBI database. To replicate the samples, real-time polymerase chain reaction technique was used for the pointed gene and the results were confirmed by the sequencing technique. Results: The mean number of CAG sequences in two groups with and without baldness, was 23.16 ± 0.47 and 23.04 ± 0.67. For GGC sequencing with and without baldness, mean count was 22.22 ± 1.45 and 19.92 ± 81.2, respectively, which was significantly higher in the group with baldness. There was no association between number of CAG sequence and improvement in hair loss or the level of patients' satisfaction, but lower number of GGC sequences was associated with higher rate of stopping hair loss, more new hair growth, higher level of satisfaction, and more clinical response to finasteride and clinical improvement in AGA patients. Conclusion: Counting of GGC sequence in the gene encoding the androgen receptor is associated with an increase in odds of baldness and a decrease in the response rate to finasteride in AGA patients.
Low-dose oral minoxidil as treatment for non-scarring alopecia: a systematic review
Background: Topical minoxidil has been used for almost 40 years to treat alopecia. There is growing evidence supporting off-label use of low-dose oral minoxidil. Objective: To conduct a systematic review evaluating the use of oral minoxidil for all types of alopecia. Methods: A primary literature search was conducted using PubMed in May 2019, utilizing the search term "oral minoxidil AND (hair loss OR alopecia OR baldness)". Reviews, non-English studies, and articles concerning only topical minoxidil were excluded. Results: Ten articles were included for review comprising a total 19,218 patients (215 women and 19,003 men). Oral minoxidil dose ranged from 0.25 to 5 mg daily to twice daily. The strongest evidence existed for androgenetic alopecia and alopecia areata (AA), with 61-100% and 18-82.4% of patients demonstrating objective clinical improvement. Successful treatment of female pattern hair loss, chronic telogen effluvium, monilethrix, and permanent chemotherapy-induced alopecia was also reported. The most common adverse effects with oral minoxidil included hypertrichosis and postural hypotension. Conclusion: Oral minoxidil is a safe and successful treatment of androgenic alopecia and AA. In addition to its therapeutic benefits, practical advantages over topical minoxidil stem from improved patient compliance.
Minoxidil Sulfotransferase Enzyme (SULT1A1) genetic variants predicts response to oral minoxidil treatment for female pattern hair loss
Safety of low-dose oral minoxidil treatment for hair loss. A systematic review and pooled-analysis of individual patient data
low dose oral minoxidil (OM) is an increasingly used treatment for androgenetic alopecia and other types of hair loss. to analyze available data of patients treated with OM, focusing on safety and adverse effects. a search in PubMed and EMBASE was performed for studies reporting the treatment of alopecia with OM. Individual patient data available for pooled-analysis were sex, dose of OM, presence of hypertrichosis and lower limb edema. 14 studies including 442 patients were analyzed. OM was used at doses between 0.25 and 5 mg, for eight different types of alopecia. Hypertrichosis was observed in 24% of patients. All doses had an increased odds ratio of hypertrichosis, compared to 0.25 to 0.5 mg (P < .001). Pedal edema was observed in 2% and was also associated with higher doses of OM (P = .009). Postural hypotension and heart rate alterations occurred only in 1.1% and 1.3% of the patients, respectively. Efficacy of OM could not be analyzed due to heterogeneous studies. However, four studies using OM for androgenetic alopecia reported a clinical response in 70% to 100% of the patients. Low dose OM is a safe and well-tolerated treatment for hair loss, presenting a lower adverse effect rate than standard doses.
Micro needling: A novel therapeutic approach for androgenetic alopecia, A Review of Literature
Androgenetic alopecia (AGA) is an androgen-dependent hereditary trait resulting in hair miniaturization. It is the most common type of alopecia in men and women. During the last years, multiple treatment modalities have been studied, but only topical minoxidil and finasteride have been approved by the US Food and Drug Administration. Microneedling (MN) is a minimally invasive technique that induces collagen formation, as well as growth factors production and neovascularization. Even though not many studies of MN in alopecia have been performed, it remains a favorable treatment modality; however, no standardized protocol for MN in hair loss has been proposed yet. Current evidence is not sufficient to allow a direct comparison with other therapies, but it shows promises to increase hair density, thickness, and quality of hair, especially when combined with other treatments or when used as a drug delivery system. This article aims to summarize the available literature regarding the use of MN alone or associated with other therapies for the treatment of androgenetic alopecia.
Tocopherol Moderately Induces the Expressions of Some Human Sulfotransferases, which are Activated by Oxidative Stress
Oxidative stress is generated in biological system by several endogenous/exogenous factors like environmental-pollution/toxicity/diseases and by daily-life-stress. We previously showed that oxidative-stress impaired the activities/expressions of phase-II drug-metabolizing enzyme, sulfotransferases (SULTs). The SULT catalyzes sulfation of endogenous/exogenous compounds. Vitamin E is globally consumed by a large number of individuals for the cellular protection from oxidative stress and aging. Here, vitamin E (tocopherol; α/γ and tocotrienol; α/γ; 0, 1, 10, or 100 μM) was tested in human carcinoma cell line, HepG2 for their influences on SULTs expression/(western blotting). The effects of oxidant (glutathione-oxidized/GSSG) or reductant (glutathione-reduced/GSH, Dithiothreitol/DTT) on SULT activities were studied in rat-liver/human intestinal tissues. Results suggest, tocopherol is more inductive to monoamine-SULT (MPST) and Dehydroepiandrosterone-SULT (DHEAST) compared to that of tocotrienol (inconsistent change in PPST, phenol sulfotransferase/MPST/EST, estrogen sulfotransferase). The nuclear-factor constitutive androstane receptor (CAR) was found to be induced moderately. This study overall describes that vitamin E moderately influences SULTs expression. The induction ability of tocopherol should be judged taking into account its long-term consummation. Oxidative stress activates rat and human SULTs activities and expressions. Further studies are necessary in this regard.
Comparative Evaluation of the Clinical Efficacy of PRP-Therapy, Minoxidil, and Their Combination with Immunohistochemical Study of the Dynamics of Cell Proliferation in the Treatment of Men with Androgenetic Alopecia
Platelet-rich plasma (PRP) therapy has been considered as a promising treatment for androgenetic alopecia (AGA). The aim of the study was comparative evaluation of the clinical efficacy of PRP-therapy, minoxidil, and their combination in the treatment of men with AGA and to evaluate the effects of PRP on the proliferation of hair follicle (HF) cells in skin biopsy. Materials and methods: The study involved 69 men who were divided into 3 groups who received PRP therapy, minoxidil, and their combination. The clinical efficacy of the therapy was evaluated by the dynamics of morphometric of hairs. To assess cell proliferation antibodies to β-catenin, CD34, Ki67, and to Dkk-1 were used. Results: PRP treatment was more effective than minoxidil therapy (p = 0.005). Complex therapy turned out to be more effective than minoxidil monotherapy (p < 0.0001) and PRP monotherapy (p = 0.007). After applying PRP the absolute and relative values of the β-catenin and CD34 expression area increased; an increase in Ki67+ index was also significant. Conclusions: PRP can be considered as a treatment option for AGA. Combined PRP and minoxidil use seems promising for the treatment of AGA. PRP increase in the proliferative activity of HF cells and improves hair morphology in patients with AGA.
Decreased phenol sulfotransferase activities associated with hyperserotonemia in autism spectrum disorders
Hyperserotonemia is the most replicated biochemical abnormality associated with autism spectrum disorders (ASD). However, previous studies of serotonin synthesis, catabolism, and transport have not elucidated the mechanisms underlying this hyperserotonemia. Here we investigated serotonin sulfation by phenol sulfotransferases (PST) in blood samples from 97 individuals with ASD and their first-degree relatives (138 parents and 56 siblings), compared with 106 controls. We report a deficient activity of both PST isoforms (M and P) in platelets from individuals with ASD (35% and 78% of patients, respectively), confirmed in autoptic tissues (9 pineal gland samples from individuals with ASD-an important source of serotonin). Platelet PST-M deficiency was strongly associated with hyperserotonemia in individuals with ASD. We then explore genetic or pharmacologic modulation of PST activities in mice: variations of PST activities were associated with marked variations of blood serotonin, demonstrating the influence of the sulfation pathway on serotonemia. We also conducted in 1645 individuals an extensive study of SULT1A genes, encoding PST and mapping at highly polymorphic 16p11.2 locus, which did not reveal an association between copy number or single nucleotide variations and PST activity, blood serotonin or the risk of ASD. In contrast, our broader assessment of sulfation metabolism in ASD showed impairments of other sulfation-related markers, including inorganic sulfate, heparan-sulfate, and heparin sulfate-sulfotransferase. Our study proposes for the first time a compelling mechanism for hyperserotonemia, in a context of global impairment of sulfation metabolism in ASD.
Safety of low-dose oral minoxidil for hair loss: A multicenter study of 1404 patients
Background: The major concern regarding the use of low-dose oral minoxidil (LDOM) for the treatment of hair loss is the potential risk of systemic adverse effects. Objective: To describe the safety of LDOM for the treatment of hair loss in a large cohort of patients. Methods: Retrospective multicenter study of patients treated with LDOM for at least 3 months for any type of alopecia. Results: A total of 1404 patients (943 women [67.2%] and 461 men [32.8%]) with a mean age of 43 years (range 8-86) were included. The dose of LDOM was titrated in 1065 patients, allowing the analysis of 2469 different cases. The most frequent adverse effect was hypertrichosis (15.1%), which led to treatment withdrawal in 14 patients (0.5%). Systemic adverse effects included lightheadedness (1.7%), fluid retention (1.3%), tachycardia (0.9%), headache (0.4%), periorbital edema (0.3%), and insomnia (0.2%), leading to drug discontinuation in 29 patients (1.2%). No life-threatening adverse effects were observed. Limitations: Retrospective design and lack of a control group. Conclusion: LDOM has a good safety profile as a treatment for hair loss. Systemic adverse effects were infrequent and only 1.7% of patients discontinued treatment owing to adverse effects.
Review of oral minoxidil as treatment of hair disorders: in search of the perfect dose
Topical minoxidil has been used for many years as treatment for different hair disorders. Even though it is an effective therapy, many patients show poor compliance due to the cosmesis, cost and side-effects. During the last few years, low-dose oral minoxidil has proven to be an alternative for patients with alopecia. We performed a literature search including all the articles that used oral minoxidil as a primary treatment in various hair diseases in order to evaluate the efficacy and safety of low-dose oral minoxidil as an alternative to topical minoxidil. Androgenetic alopecia was the most common studied condition, but others included telogen effluvium, tractional alopecia, postchemotherapy-induced alopecia, monilethrix, loose anagen hair syndrome, alopecia areata and scarring alopecias (frontal fibrosing alopecia and lichen planopilaris). Larger randomized comparative studies including standardized objective measurements should be done in order to clarify the best treatment protocol, including dosage and treatment duration. Oral minoxidil has proven to be a successful and well-tolerated alternative for patients with hair loss, including those with poor adherence to other therapies. Different dosing regimens have been utilized in scarring and non-scarring alopecia, varying from 0.25 to 5 mg daily. Higher doses have not been studied in men or women. Available literature suggests women require lower doses, from 0.25 to 2.5 mg daily, while men require higher doses for maximal efficacy, from 1.25 to 5 mg a day.
Platelet-rich plasma with low dose oral minoxidil (1.25mg versus 2.5mg) along with trichoscopic pre- and post-treatment evaluation
Background: Low dose (<5 mg) oral minoxidil (OM) seems a promising option for male androgenetic alopecia (MAGA). Aim: To evaluate the role of oral minoxidil 1.25 mg versus oral minoxidil 2.5 mg along with platelet-rich plasma in MAGA. Methods: Group A consisted of forty-seven patients which included patients on OM 1.25 mg daily and platelet-rich plasma therapy, and Group B consisted of 48 patients on OM 2.5 mg daily and platelet-rich plasma therapy. Photographs were taken before and after treatment along with trichoscopic evaluation. Selection of the dermoscopic variables was based on the published literature. Results: At 24 weeks, marked improvement on Global clinical photography (GCP) were seen in 19/47 (40.4%) in Group A and 28/48 (58.3%) patients in Group B with p value of 0.058. The total increase in total hair/cm2 was around 24 and 36 in group A and B, respectively, with p > 0.05. The percentage increase in mean total hair count/cm2 after 6 month of treatment was 15.41% in group A and 22.15% in group B, but they were not statistically significant. The patient satisfaction score on a Likert scale between both group were statistically significant,with Group B patients having a better satisfaction score. Conclusion: This is a pilot study where OM along with PRP at different dosage (1.25mg vs 2.5mg) has been compared, low dose OM with PRP can be used in patients who are apprehensive of taking finasteride or dutasteride and are less responsive to topical minoxidil alone.
SULT genetic polymorphisms: physiological, pharmacological and clinical implications
Introduction: Cytosolic sulfotransferases (SULTs)-mediated sulfation is critically involved in the metabolism of key endogenous compounds, such as catecholamines and thyroid/steroid hormones, as well as a variety of drugs and other xenobiotics. Studies performed in the past three decades have yielded a good understanding about the enzymology of the SULTs and their structural biology, phylogenetic relationships, tissue/organ-specific/developmental expression, as well as the regulation of the SULT gene expression. An emerging area is related to the functional impact of the SULT genetic polymorphisms. Areas covered: The current review aims to summarize our current knowledge about the above-mentioned aspects of the SULT research. An emphasis is on the information concerning the effects of the polymorphisms of the SULT genes on the functional activity of the SULT allozymes and the associated physiological, pharmacological, and clinical implications. Expert opinion: Elucidation of how SULT SNPs may influence the drug-sulfating activity of SULT allozymes will help understand the differential drug metabolism and eventually aid in formulating personalized drug regimens. Moreover, the information concerning the differential sulfating activities of SULT allozymes toward endogenous compounds may allow for the development of strategies for mitigating anomalies in the metabolism of these endogenous compounds in individuals with certain SULT genotypes.
Minoxidil: a comprehensive review
Topical minoxidil (5% foam, 5% solution, and 2% solution) is FDA-approved for androgenetic alopecia (AGA) in men and women.Mechanism of action: Minoxidil acts through multiple pathways (vasodilator, anti-inflammatory agent, inducer of the Wnt/β-catenin signaling pathway, an antiandrogen), and may also affect the length of the anagen and telogen phases.Pharmacokinetics: Approximately 1.4% of topical minoxidil is absorbed through the skin. Minoxidil is a prodrug that is metabolized by follicular sulfotransferase to minoxidil sulfate (active form). Those with higher sulfotransferase activity may respond better than patients with lower sulfotransferase activity.Clinical efficacy (topical minoxidil): In a five-year study, 2% minoxidil exhibited peak hair growth in males at year one with a decline in subsequent years. Topical minoxidil causes hair regrowth in both frontotemporal and vertex areas. The 5% solution and foam were not significantly different in efficacy from the 2% solution.Oral and Sublingual minoxidil (not FDA approved; off-label): After 6 months of administration, minoxidil 5 mg/day was significantly more effective than topical 5% and 2% in male AGA. Low-dose 0.5-5 mg/day may also be safe and effective for female pattern hair loss and chronic telogen effluvium. Sublingual minoxidil may be safe and effective in male and female pattern hair loss.
Influence of SULT1A1*2 Polymorphism on Plasma Efavirenz Concentration in Thai HIV-1 Patients
Purpose: Plasma efavirenz (EFV) concentrations within therapeutic levels are essential to successfully treat patients suffering from human immunodeficiency virus (HIV) type 1. In addition to the drug-metabolizing enzyme CYP2B6, other phase II drug-metabolizing enzymes and transporters may have an important role in the pharmacokinetics of EFV. Thus, the influence of phase II drug-metabolizing enzymes and drug transporters on plasma EFV levels was investigated in Thai HIV patients receiving EFV. Patients and methods: Genotyping was performed by TaqMan® real-time PCR in 149 HIV-infected Thai adults, and plasma efavirenz concentration was measured by a validated high-performance liquid chromatography in 12 hours after dosing steady-state plasma samples at week 12 and 24. Results: Patients with three or more copies of SULT1A1 had significantly lower median plasma EFV concentrations than those carrying two copies at week 12 (p=0.046) and SULT1A1*2 (c.638G>A) carriers had significantly lower median plasma EFV concentrations compared to those not carrying the variant at week 24 (p=0.048). However, no significant association was found after adjusting for CYP2B6 genotype. Conclusion: Genetic variation in a combination of SULT1A1*2 and SULT1A1 copy number may contribute to variability in EFV metabolism and thereby may impact drug response. The influence of a combination between the SULT1A1 and CYP2B6 genotype on EFV pharmacokinetics should be further investigated in a larger study population.
Platelet-Rich Plasma with Microneedling in Androgenetic Alopecia: Study of Efficacy of the Treatment and the Number of Sessions Required
Background: Platelet-rich plasma (PRP) is a simple and safe procedure, which has been used for soft tissue and wound healing. PRP has been used in dermatology for skin rejuvenation and alopecia. Objective: The objective of our study was to study efficacy of PRP with microneedling in patients with androgenetic alopecia (AGA) and to assess number of sessions required for a patient. Materials and methods: Sixty patients diagnosed with AGA were studied between August 2016 and October 2018 who did not respond to minoxidil and finasteride. PRP was prepared by centrifugation of patients' blood. PRP with microneedling was done for all patients under aseptic conditions. Four to six sessions were done at an interval of 4 weeks. Subjective and objective scores were assessed based on a visual analog global score. Assessment was done at the first session, every next sitting, and 4 weeks after the last sitting. Follow-up was done at 3rd and 6th month after the last sitting. Results: According to subjective scores, two patients (3.33%) had excellent results, 24 (40%) very good, 22 (36.6%) good, 6 (10%) fair results, and 6 (10%) did not have any response. Objective assessment scores showed that two patients (3.33%) had excellent results, 26 (43.3%) very good, 21 (35%) good, 7 (11.6%) had fair results, and 4 (6.7%) did not have any response. Fifty patients underwent four sessions out of which 40 (i.e. 66%) patients had very good results. Only 10 patients required more than four sessions to achieve good results. Patients were happy with four sessions. There were no side effects noted either during or after the treatment. Conclusion: This study shows PRP with microneedling as an efficacious treatment for AGA and augments the effects of conventional treatment. This study sets example for assessing the number of PRP sessions. A minimum of four sessions is required to achieve very good results.
Sulfation of minoxidil by human platelet sulfotransferase
In an attempt to determine whether (1) sulfotransferase activity in human platelets would convert minoxidil to minoxidil sulfate and (2) inter-subject variations in this sulfotransferase activity could be noted, platelet homogenates were incubated with minoxidil and 35S-PAPS in HEPES buffer at 37 degrees C for 30 min. Radioactivity which was extracted into ethyl acetate and shown by HPLC to elute with authentic minoxidil sulfate was counted by scintillation counting. Aliquots of the platelet homogenates were also preincubated at 43 degrees C for 15 min to determine the thermal stability of the sulfotransferase activity. Sulfotransferase activity in platelets from 48 adult males ranged from 0.9-13.2 pmol minoxidil sulfate produced/10(7) platelets per 30 min (mean 4.91 +/- 2.84 pmol/10(7) platelets per 30 min +/- SD). Thermal stable sulfotransferase activity ranged from 0.2-7.6 pmol minoxidil produced/10(7) platelets per 30 min and varied from 15 to 57% of the total sulfotransferase activity. Thus, the results indicate that human platelets can effect the sulfation of minoxidil and that sulfotransferase activity does show inter-subject variation.
Comparative histological and immunohistochemical study on the effect of platelet rich plasma/minoxidil, alone or in combination, on hair growth in a rat model of androgenic alopecia
Background: Androgenic alopecia (AGA) is the commonest cause of hair loss in men with limited treatment options. Aim of the work: To compare the efficacy of PRP and minoxidil on experimentally induced AGA in adult male albino rats. Materials and methods: Thirty male albino rats were used. Group I (control group). Group II (AGA group): received testosterone only. Group III: received topical minoxidil. Group IV: received PRP /three days. Group V: received PRP and topical minoxidil. Results: Groups III, IV, and V showed significant increase in mean epidermal thickness, mean numbers of total hair follicles and anagen hair follicles, and decrease in telogen hair follicles compared to AGA group. Group V showed the best results. AGA group showed perifollicular fibrosis and follicular streamers. They were absent in PRP group and group V. Significant decrease of Ki-67 positive cells in AGA. PRP and minoxidil groups showed a significant increase in number of Ki-67 positive cells compared to control and AGA groups. Group V showed the highest number of Ki-67 positive cells. Conclusion: PRP was more effective than minoxidil in treatment of experimentally induced AGA in rats. The best results were obtained when PRP and minoxidil were administered together.
Oral minoxidil use in androgenetic alopecia and telogen effluvium
While current studies have supported oral minoxidil as a novel, adjunctive therapy in non-scarring forms of alopecia, there continues to be limited data on oral minoxidil for these conditions. To assess oral minoxidil use in the treatment of androgenetic alopecia and telogen effluvium, a multi-center, retrospective analysis was conducted in 105 adult patients treated for androgenetic alopecia and/or telogen effluvium with oral minoxidil (dose range 0.625-2.5 mg) once daily for ≥ 52 weeks, case matched by age (± 5 years) and gender with 105 controls with androgenetic alopecia and/or telogen effluvium who were not treated with oral minoxidil. 80 women (76.2%) with a mean age of 57.5 ± 13.56 (range 24-80) and 25 men (23.8%) with a mean age of 40.4 ± 13.79 (range 19-63) were included. Efficacy was evaluated based on provider assessment of clinical response and clinical photographic evaluation using a 3-point scale (worsening, stabilization, and improvement). 52.4% of patients demonstrated clinical improvement and 42.9% demonstrated stabilization. There was a significant difference in clinical response between the patient and control group, p < 0.001. Retrospective study design. These results suggest that oral minoxidil can be an effective treatment in androgenetic alopecia and telogen effluvium.
Combination therapy with platelet-rich plasma and minoxidil leads to better clinical results than monotherapy with these methods in men with androgenetic alopecia
Platelet-rich plasma (PRP) therapy is a new method for the treatment of androgenetic alopecia (AGA), the effectiveness and safety of which continues to be studied. Information on comparative efficacy when combining PRP with other methods of treatment is limited. The aim of the study was a comparative evaluation of the clinical efficacy of minoxidil, PRP therapy, and their combination in the treatment of men with AGA. Materials and methods: The study included 69 men. The patients were divided into three observation groups: the main group (25 people, received applications of a 5% solution of minoxidil in combination with PRP injections), the comparison group (22 people, received intradermal injections of PRP), and the control group (22 people, received applications of a 5% solution of minoxidil). The clinical efficacy of the therapy was evaluated by the dynamics of morphometric indicators of hair growth using a digital camera and the software. Results: It was established that after complex therapy in the form of minoxidil applications and injections of PRP, the hair density increased by 32% (P = 0.00004), the diameter of the hair shafts by 26% (P = 0.00004), the share of vellus hair decreased by 30% (P = 0.00082), and the proportion of telogen hair decreased by 39% (P = 0.00008). The results of using complex therapy significantly exceeded the clinical effect of platelet-rich plasma and topical applications of a 5% solution of minoxidil. Conclusions: The data obtained allows suggesting that PRP and minoxidil potentiate each other's action when used together and their complex application seems promising for the treatment of androgenetic alopecia.
SLC4A4, FRAS1, and SULT1A1 Genetic Variations Associated With Dabigatran Metabolism in a Healthy Chinese Population
Background: The purpose of this study was to identify genetic variations associated with the metabolism of dabigatran in healthy Chinese subjects, with particular focus given to pharmacokinetics (PK) and pharmacodynamics (PD). Methods: Healthy Chinese adults aged 18-65 years with unknown genotypes from a bioequivalence trial were included according to the protocol registered at ClinicalTrial.org (NCT03161496). All subjects received a single dose (150 mg) of dabigatran etexilate. PK (main outcomes: area under the concentration-time, AUC0-t, of total and free dabigatran) and PD (main outcomes: anti-FIIa activity, APTT, and PT) parameters were evaluated. Whole-exome sequencing and genome-wide association analyses were performed. Additionally, candidate gene association analyses related to dabigatran were conducted. Results: A total of 118 healthy Chinese subjects were enrolled in this study. According to the p-value suggestive threshold (1.0 × 10-4), the following three SNPs were found to be associated with the AUC0-t of total dabigatran: SLC4A4 SNP rs138389345 (p = 5.99 × 10-5), FRAS1 SNP rs6835769 (p = 6.88 × 10-5), and SULT1A1 SNP rs9282862 (p = 7.44 × 10-5). Furthermore, these SNPs were also found to have significant influences on the AUC0-t of free dabigatran, maximum plasma concentration, and anti-FIIa activity (p < 0.05). Moreover, we identified 30 new potential SNPs of 13 reported candidate genes (ABCB1, ABCC2, ABCG2, CYP2B6, CYP1A2, CYP2C19, CYP3A5, CES1, SLCO1B1, SLC22A1, UGT1A1, UGT1A9, and UGT2B7) that were associated with drug metabolism. Conclusion: Genetic variations were indeed found to impact dabigatran metabolism in a population of healthy Chinese subjects. Further research is needed to explore the more detailed functions of these SNPs. Additionally, our results should be verified in studies that use larger sample sizes and investigate other ethnicities.
A Comparative Study of Efficacy of 5% Minoxidil and 5% Minoxidil Plus Platelet-Rich Plasma in Same Patient for Treatment of Androgenetic Alopecia
Background: Androgenetic alopecia (AGA) is characterized by androgen-related progressive thinning of the scalp hair in a defined pattern. It has an effect on social and psychological well-being of the patient. It is often recalcitrant to medical treatment alone. Aim: The aim of the study was to compare the efficacy of 5% minoxidil and 5% minoxidil plus platelet-rich plasma (PRP) in same patient for the treatment of AGA. Materials and methods: A prospective randomized study was conducted on 50 patients of AGA attending the outdoor department. Scalp of each patient was divided into right side and left side, to compare the effectiveness of 5% minoxidil on the right side with combination of 5% minoxidil and intradermal PRP on the left side at an interval of 1 month for a period of 6 months. Clinical improvement was assessed monthly till 6 months by the serial hair pull test, global photography, patient satisfaction score, trichoscopic evaluation, and hair density. Results: For post-procedure subjective perception at the end of 6 months, the minoxidil 5% side showed good response in 41% (n = 18), moderate in 20% (n = 9), and poor in 39% (n = 17), whereas the PRP + minoxidil 5% side showed good response in 59% (n = 26), moderate in 16% (n = 7), and poor in 25% (n = 11) of the patients. Conclusion: The combination consists of 5% minoxidil and intradermal PRP, which appears to be simple, safe, and effective treatment in AGA. It can be used in poor responders in conventional medical therapy.
Efficacy and Safety of 5% Minoxidil Alone, Minoxidil Plus Oral Spironolactone, and Minoxidil Plus Microneedling on Female Pattern Hair Loss: A Prospective, Single-Center, Parallel-Group, Evaluator Blinded, Randomized Trial
Background: The efficacy of topical minoxidil (MX) alone on female pattern hair loss (FPHL) is limited. Combination therapy based on topical MX is currently expected to provide better outcomes. Objectives: This study aimed to assess whether the combined therapies including MX plus oral spironolactone (SPT) and MX plus microneedling (MN) have advantages in efficacy and safety over topical MX alone on mild-to-moderate FPHL with normal hormone levels in the blood and regular menstrual cycle. Methods: A prospective, single-center, parallel-group, evaluator blinded, randomized trial including 120 non-menopause women with proven FPHL (Sinclair class II-III) was performed in China. Patients were randomly assigned to three groups, namely, the MX group (5% topical MX alone, once daily), the MX + SPT group (MX plus SPT 80-100 mg daily), and the MX+MN group (MX plus MN every 2 weeks, 12 sessions). The change from the baseline to week 24 was assessed in hair growth (hair density and diameter under dermoscope), scalp tissue structure (epidermal thickness, dermis thickness, and average hair follicle diameter under ultrasound biomicroscopy), physician's global assessment (using a 7-point global-assessment scale and Sinclair's stage change), patient evaluation (Women's Androgenetic Alopecia Quality of Life Questionnaire and Sinclair's hair-shedding score) and side effects. Results: In total, 115 participants completed the trial. At week 24, the hair density increased most in MX + MN group and increased least in MX group (p < 0.001 for MX + MN group vs. MX + SPT group; p = 0.009 for MX + SPT group vs. MX group). The hair shaft diameter significantly increased in all groups (p < 0.001, respectively), but there were no significant differences among the three groups (p = 0.905). The epidermal thickness and average hair follicle diameter only increased in MX + MN group. Dermis thickness increased in all groups, but there were no significant differences among the three groups. Both physician's and patient assessments showed improvement in all three groups. Scalp pruritus was the most common side effect. The MX + SPT group had the most reported adverse effects. Limitations: The main limitations of this study are the relatively small sample size, the exclusion of severe FPHL patients, and the potential bias from unblinded treatments among the 3 groups. Conclusion: Topical MX combined with MN is a better choice than either MX plus oral SPT or MX alone for the treatment of mild-to-moderate FPHL patients.
Comparison of oral minoxidil, finasteride, and dutasteride for treating androgenetic alopecia
Background: Androgenetic alopecia (AGA) is the most common cause of hair loss, often challenging to treat. While oral finasteride (1 mg/d) is an FDA-approved treatment for male AGA, oral minoxidil and oral dutasteride are not approved yet. However, clinicians have been increasingly using these two drugs off-label for hair loss. Recently, Japan and South Korea have approved oral dutasteride (0.5 mg/d) for male AGA. Efficacy and safety: A probable efficacy ranking, in decreasing order, is - dutasteride 0.5 mg/d, finasteride 5 mg/d, minoxidil 5 mg/d, finasteride 1 mg/d, followed by minoxidil 0.25 mg/d. Oral minoxidil predominantly causes hypertrichosis and cardiovascular system (CVS) symptoms/signs in a dose-dependent manner, whereas oral finasteride and dutasteride are associated with sexual dysfunction and neuropsychiatric side effects. Pharmacokinetics and pharmacodynamics: The average plasma half-lives of minoxidil, finasteride, and dutasteride are ∼4 h, ∼4.5 h, and ∼5 weeks, respectively. Minoxidil acts through multiple pathways to promote hair growth. It has been shown as a vasodilator, an anti-inflammatory agent, a Wnt/β-catenin signaling inducer, and an antiandrogen. Finasteride inhibits 5α-reductase (5AR) type II isoenzyme, while dutasteride inhibits both type I and type II. Thus, dutasteride suppresses DHT levels more than finasteride in the serum and scalp.
Aha1 Is an Autonomous Chaperone for SULT1A1
The cochaperone Aha1 activates HSP90 ATPase to promote the folding of its client proteins; however, very few client proteins of Aha1 are known. With the use of an ascorbate peroxidase (APEX)-based proximity labeling method, we identified SULT1A1 as a proximity protein of HSP90 that is modulated by genetic depletion of Aha1. Immunoprecipitation followed by Western blot analysis showed the interaction of SULT1A1 with Aha1, but not HSP90. We also observed a reduced level of SULT1A1 protein upon genetic depletion of Aha1 but not upon pharmacological inhibition of HSP90, suggesting that the SULT1A1 protein level is regulated by Aha1 alone. Maturation-dependent interaction assay results showed that Aha1, but not HSP90, binds preferentially to newly synthesized SULT1A1. Reconstitution of Aha1-depleted cells with wild-type Aha1 and its E67K mutant, which is deficient in interacting with HSP90, restored SULT1A1 protein to the same level. Nonetheless, complementation of Aha1-depleted cells with an Aha1 mutant lacking the first 20 amino acids, which disrupts its autonomous chaperone function, was unable to rescue the SULT1A1 protein level. Together, our study revealed, for the first time, Aha1 as an autonomous chaperone in regulating SULT1A1. SULT1A1 is a phase-II metabolic enzyme, where it adds sulfate groups to hydroxyl functionalities in endogenous hormones and xenobiotic chemicals to improve their solubilities and promote their excretion. Thus, our work suggests the role of Aha1 cochaperone in modulating the detoxification of endogenous and environmental chemicals.
Sulfotransferase SULT1A1 activity in hair follicle, a prognostic marker of response to the minoxidil treatment in patients with androgenetic alopecia: a review
Androgenetic alopecia (AGA) is a very common type of alopecia in men and women. It may have a negative effect on the quality of life. The most widely used pharmaceutical treatment for AGA is topical minoxidil and it is also the only external treatment of pattern hair loss. There are two forms of this treatment - 5% and 2% minoxidil. The correlation between SULT1A1 expression in the scalp and minoxidil response has been previously reported. Due to the prolonged treatment time required to elicit a therapeutic response (approximately 6 months) combined with the variable efficacy of minoxidil in the general population, expression of SULT1A1 as a biomarker for predicting treatment response would have a significant clinical utility.
Pharmacogenetics of human sulfotransferases and impact of amino acid exchange on Phase II drug metabolism
Sulfotransferases (SULTs) are Phase II drug-metabolizing enzymes (DMEs) catalyzing the sulfation of a variety of endogenous compounds, natural products, and drugs. Various drugs, such as nonsteroidal anti-inflammatory drugs (NSAIDS) can inhibit SULTs, affecting drug-drug interactions. Several polymorphisms have been identified for SULTs that might be crucial for interindividual variability in drug response and toxicity or for increased disease risk. Here, we review current knowledge on non-synonymous single nucleotide polymorphisms (nsSNPs) of human SULTs, focusing on the coded SULT allozymes and molecular mechanisms explaining their variable activity, which is essential for personalized medicine. We discuss the structural and dynamic bases of key amino acid (AA) variants implicated in the impacts on drug metabolism in the case of SULT1A1, as revealed by molecular modeling approaches.
Pericardial, pleural effusion and anasarca: A rare complication of low-dose oral minoxidil for hair loss
The physiological and pharmacological roles of prostaglandins in hair growth
Hair loss is a common status found among people of all ages. Since the role of hair is much more related to culture and individual identity, hair loss can have a great influence on well-being and quality of life. It is a disorder that is observed in only scalp patients with androgenetic alopecia (AGA) or alopecia areata caused by stress or immune response abnormalities. Food and Drug Administration (FDA)-approved therapeutic medicines such as finasteride, and minoxidil improve hair loss temporarily, but when they stop, they have a limitation in that hair loss occurs again. As an alternative strategy for improving hair growth, many studies reported that there is a relationship between the expression levels of prostaglandins (PGs) and hair growth. Four major PGs such as prostaglandin D2 (PGD2), prostaglandin I2 (PGI2), prostaglandin E2 (PGE2α), and prostaglandin F2 alpha (PGF2α) are spatiotemporally expressed in hair follicles and are implicated in hair loss. This review investigated the physiological roles and pharmacological interventions of the PGs in the pathogenesis of hair loss and provided these novel insights for clinical therapeutics for patients suffering from alopecia.
Role of Oral Minoxidil in Patterned Hair Loss
Recent studies have shown that low-dose oral minoxidil (OM) can be a safe and effective treatment of numerous hair disorders including male-patterned hair loss (MPHL) and female-patterned hair loss (FPHL). There are several practical advantages of OM over its topical formulation: enhanced cosmesis, cost-savings, and the possibility of co-therapy with other topical formulations or topicals used for camouflage. This treatment may be particularly helpful for patients who are unable to tolerate topical minoxidil or other systemic treatments. Doses ranging from 0.25 to 1.25 mg daily are usually used for FPHL and doses ranging from 2.5 to 5 mg/day for MPHL. The low side-effect profile of low-dose OM allows for long-term adherence to the medication and favorable clinical response, resulting in stabilization and improvement of hair loss. More studies are needed to test the efficacy of OM in other types of alopecia as well as additional comparative studies assessing OM to other commonly used medications.
Observation on the Efficacy of a Combined Treatment for Moderate and Severe Androgenetic Alopecia Incorporating Electric Microneedles
Objective: To evaluate the effectiveness and safety of a combined treatment for moderate and severe androgenetic alopecia (AGA) involving the use of electric microneedles. Methods: A total of 83 patients with moderate to severe AGA in the Department of Dermatology at Beijing Jishuitan Hospital were included in this study. The male patients were administered finasteride orally and 5% minoxidil for external use, while the female patients were given spironolactone orally or Diane-35 and 2% minoxidil for external use. All the patients were then treated via electric microneedle therapy alongside the YUFA ®medical care package (Foshan, China) once a week for 1-28 weeks. The seven-point method and root hair measurement using a hair mirror were adopted to evaluate the efficacy and any adverse reactions of the combined treatment. Results: Eleven patients were treated for 1-3 weeks, 60 for 4-12 weeks, and 12 for more than 12 weeks. The efficacy evaluation using the seven-point method for 12 weeks of treatment indicated a 100% response rate, specifically, a 42.1% mild improvement rate, a 38.6% moderate improvement rate, and a 19.3% marked improvement rate. Besides, the efficacy assessment was also completed with root hair count method and the number of hair roots measured at fixed points were 148.67±11.15, 158.13±5.11 and 169.75±2.06 after treatment time at 16, 20 and 24 weeks, respectively. Of note, a statistical difference in the number of hair roots could be observed during the period of week 20-week 24 (P < 0.01). Conclusion: The combined treatment of moderate to severe AGA using the electric microneedle technique has a clear effect and can effectively increase the hair density. With a simple operation and mild side effects, the technique has wide application prospects.
Minoxidil Regulates Aging-Like Phenotypes in Rat Cortical Astrocytes In Vitro
Mainly due to the slanted focus on the mechanism and regulation of neuronal aging, research on astrocyte aging and its modulation during brain aging is scarce. In this study, we established aged astrocyte culture model by long-term culturing. Cellular senescence was confirmed through SA-β-gal staining as well as through the examination of morphological, molecular, and functional markers. RNA sequencing and functional analysis of astrocytes were performed to further investigate the detailed characteristics of the aged astrocyte model. Along with aged phenotypes, decreased astrocytic proliferation, migration, mitochondrial energetic function and support for neuronal survival and differentiation has been observed in aged astrocytes. In addition, increased expression of cytokines and chemokine-related factors including plasminogen activator inhibitor -1 (PAI-1) was observed in aged astrocytes. Using the RNA sequencing results, we searched potential drugs that can normalize the dysregulated gene expression pattern observed in long-term cultured aged astrocytes. Among several candidates, minoxidil, a pyrimidine-derived anti-hypertensive and anti-pattern hair loss drug, normalized the increased number of SA-β-gal positive cells and nuclear size in aged astrocytes. In addition, minoxidil restored up-regulated activity of PAI-1 and increased mitochondrial superoxide production in aged astrocytes. We concluded that long term culture of astrocytes can be used as a reliable model for the study of astrocyte senescence and minoxidil can be a plausible candidate for the regulation of brain aging.
Pilot study: genetic distribution of AR, FGF5, SULT1A1 and CYP3A5 polymorphisms in male Mexican population with androgenetic alopecia
Genetics is responsible for 80% of androgenetic alopecia (AGA) predisposition. Several single nucleotide polymorphisms (SNPs) have been linked to AGA risk and the metabolism of its first-line therapies. Genotypic and allelic frequencies have not been described in Mexican individuals; therefore, the aim of this study was to describe the genetic distribution of SNPs associated with AGA predisposition and drug metabolism. Using Real Time-PCR, we genotyped SNPs rs4827528 (AR), rs7680591 (FGF5), rs1042028, rs1042157, rs788068 and rs6839 (SULT1A1) and rs776746 (CYP3A5) in 125 (controls = 60, cases = 65) male volunteers from Northern and Western Mexico. The SULT1A1 SNPs rs1042028 (C/T) and rs788068 (T/A/C) resulted in a 100% distribution of the ancestral allele C and mutated allele A, respectively; rs1042028 diverges from the previously reported frequency, while the rs788068 ancestral allele was found to be more predominant than the reported frequency. Rs1042028, rs788068 and rs4827528, were not in Hardy-Weinberg (HW) equilibrium; conversely, rs1042157 and rs6839, rs776746, and rs7680591 followed HW principles. A statistically significant difference (P<0.05) was obtained for the rs1042157 allelic frequency between cases and controls in Western Mexico. We reported the genotypic and allelic frequencies of seven polymorphisms in Mexican individuals from Northern and Western Mexico.
Human skin and platelet minoxidil sulfotransferase activities: biochemical properties, correlations and contribution of thermolabile phenol sulfotransferase
Human scalp skin high speed supernatants were used to test whether minoxidil sulfotransferase (MNX-ST) and phenol sulfotransferase (PST) activities were present. Platelet homogenates from the same skin donors were used to test whether levels of sulfotransferase activities in the blood platelet would reflect levels of the enzyme activities in skin. Dopamine, p-nitrophenol and minoxidil were used as substrates for skin and platelet thermolabile (TL PST), thermostable (TS PST) and MNX-ST activities, respectively. Biochemical properties of each skin enzyme were the same as the platelet enzymes with respect to apparent Km values for substrates, pH optima, thermal stabilities and responses to inhibition by 2,6-dichloro-4-nitrophenol (DCNP). An unexpected finding was that skin and platelet MNX-ST thermal stabilities and responses to DCNP were more similar to TL PST than to TS PST, the enzyme reported to be responsible for MNX-ST activity. There were significant positive correlations of platelet sulfotransferases with the relative levels of activities of the same skin sulfotransferases. Unexpected findings were significant positive correlations of MNX-ST and TL PST activities. Partially purified platelet TS PST assayed with minoxidil as the substrate showed a response to DCNP and thermal stability that were the same as TS PST. Platelet TL PST assayed with minoxidil showed thermal stability and a response to DCNP that were essentially the same as TL PST. The results indicated that not only TS PST, but also TL PST activities in human skin and platelet contributed to MNX-ST activity. It will be feasible to test whether measures of platelet PST activities will predict physiologic responses to minoxidil.
Characterization of recombinant human liver thermolabile phenol sulfotransferase with minoxidil as the substrate
Minoxidil, a potent antihypertensive agent and hair growth stimulator, is metabolized by phenol sulfotransferase to its activated form, minoxidil sulfate. The thermostable form of phenol sulfotransferase was reported to be the enzyme that catalyzed the reaction. Our previous findings with partially purified human platelet preparations indicated that the thermolabile form of phenol sulfotransferase also catalyzed the sulfation of minoxidil. To confirm and to characterize precisely the activity of thermolabile phenol sulfotransferase toward minoxidil, we investigated the ability of the enzyme expressed from a human liver cDNA clone to sulfate minoxidil during testing of thermal stability and of inhibition by 2,6-dichloro-4-nitrophenol and NaCl. The cDNA encoded thermolabile phenol sulfotransferase activity assayed with minoxidil behaved in the same fashion as the activity measured with dopamine, a finding that confirmed that this enzyme activity sulfated minoxidil. Thus, thermolabile phenol sulfotransferase must be taken into account with the thermostable enzyme when estimating the human tissue sulfotransferase contribution to minoxidil sulfation.
Flavonoids, potent inhibitors of the human P-form phenolsulfotransferase. Potential role in drug metabolism and chemoprevention
The common dietary constituent quercetin was a potent inhibitor of sulfoconjugation of acetaminophen and minoxidil by human liver cytosol, partially purified P-form phenolsulfotransferase (PST), and recombinant P-form PST, with IC50 values of 0.025-0.095 microM. Quercetin inhibition of acetaminophen was noncompetitive with respect to acceptor substrate, with a Ki value of 0.067 microM. A number of other flavonoids, such as fisetin, galangin, myricetin, kaempferol, chrysin, and apigenin, were also potent inhibitors of P-form PST-mediated sulfation, with IC50 values < 1 microM. Studies of structural analogs indicated the flavonoid 7-hydroxyl group as particularly important for potent inhibition. Potential human metabolites of quercetin were poor inhibitors. Curcumin, genistein, and ellagic acid (other polyphenolic natural products) were also inhibitors of P-form PST, with IC50 values of 0.38-34.8 microM. Quercetin was also shown to inhibit sulfoconjugation by the human hepatoma cell line Hep G2. Although less potent in this intact cell system (IC50 2-5 microM), quercetin was still more potent than 2,6-dichloro-4-nitrophenol, the classical P-form PST inhibitor that has been shown to be an inhibitor also in vivo. These observations suggest the potential for clinically important drug interactions, as well as a possible role for flavonoids as chemopreventive agents in sulfation-induced carcinogenesis.
Direct measurement and regulation of 3'-phosphoadenosine 5'-phosphosulfate (PAPS) generation in vitro
3'-Phosphoadenosine 5'-phospho[35S]sulfate (PAPS) biosynthesized from inorganic [35S]sulfate and ATP was separated from its radiolabeled precursor by reversed-phase paired-ion HPLC and quantified by on-line radiometric detection. This single-step procedure circumvents several problems inherent in conventional sulfotransferase-coupled assays employed in the measurement of PAPS formation. A good correlation was observed between the rate of PAPS generation assayed in several mammalian tissues measured by direct HPLC-radiometry and by coupling to the sulfation of minoxidil or 4-methylumbelliferone. Both AMP and ADP inhibited the rat liver sulfate-activating enzymes competitively with respect to MgATP2-, and the rate of PAPS production was decreased with decreasing ratios of [ATP]:[ADP] and [ATP]:[AMP]. It is possible that these adenine nucleotides regulate sulfate activation by kinetic control and by negative feedback modulation.
Human dehydroepiandrosterone sulfotransferase pharmacogenetics: quantitative Western analysis and gene sequence polymorphisms
Dehydroepiandrosterone sulfotransferase (DHEA ST) catalyzes the sulfation of DHEA and other hydroxysteroids. DHEA ST enzymatic activity in individual human liver biopsy samples has been shown to vary over a five-fold range, and frequency distribution histograms are bimodal, with approximately 25% of subjects included in a high activity subgroup. We set out to characterize the molecular basis for variation in human liver DHEA ST activity. The first step involved performing quantitative Western analysis of cytosol preparations from 92 human liver samples that had been phenotyped with regard to level of DHEA ST enzymatic activity. There was a highly significant correlation (r(s) = 0.635, P < 0.0001) between levels of DHEA ST activity and immunoreactive protein. We next attempted to determine whether the expression of DHEA ST might be controlled, in part, by a genetic polymorphism. DNA was isolated from three "low" and three "high" DHEA ST activity liver samples. Exons and the 5'-flanking region of the DHEA ST gene (STD) were amplified for each of these samples with the polymerase chain reaction (PCR). When compared with "wild type" STD sequence, some of the samples contained a T --> C transition at DHEA ST cDNA nucleotide 170, located within exon 2, resulting in a Met 57 --> Thr change in amino acid. Other samples contained an A --> T transversion at nucleotide 557 within STD exon 4 that resulted in a Glu 186 --> Val change. STD exons 2 and 4 were then sequenced for DNA isolated from an additional 87 liver samples that had been phenotyped with regard to level of DHEA ST enzymatic activity. The allele frequency for the exon 2 polymorphism in these samples was 0.027, whereas that for the exon 4 polymorphism was 0.038, but neither polymorphism was systematically related to the level of enzyme activity in these samples. Transient expression in COS-1 cells of cDNA that contained the nucleotide 170 and 557 polymorphisms, either separately or together, resulted in decreased expression of both DHEA ST enzymatic activity and level of immunoreactive protein, but only when the nucleotide 557 variant was present. Identification of common genetic polymorphisms within STD will now make it possible to test the hypothesis that those polymorphisms might alter in vivo expression and/or function of this important human steroid-metabolizing enzyme.
Characterization of recombinant human liver dehydroepiandrosterone sulfotransferase with minoxidil as the substrate
Biotransformation of xenobiotics and hormones through sulfate conjugation is an important metabolic pathway in humans. The activation of minoxidil, an antihypertensive agent and hair growth stimulator, by sulfation (sulfonation) is carried out by more than one sulfotransferase. Initially only the thermostable form of phenol sulfotransferase was thought to catalyze minoxidil sulfation. We document in this report the new finding that human liver dehydroepiandrosterone sulfotransferase (DHEAST), an hydroxysteroid sulfotransferase distinct from phenol sulfotransferases, also catalyzes the reaction. To characterize more precisely the activity of DHEA ST toward minoxidil, we used COS-1 cells to express DHEA ST from a human liver cDNA clone. The apparent Km values for minoxidil and [35S]3'-phosphoadenosine-5'-phosphosulfate were 3.9 mM and 0.13 microM, respectively. The 50% inactivation temperature of the COS-expressed enzyme was 42 degrees, and the IC50 value for 2,6-dichloro-4-nitrophenol was 1.4 x 10(-4) M. Both the thermal stability behavior and response to DCNP were similar when the cDNA encoded DHEA ST was assayed with DHEA or minoxidil as a substrate. NaCl led to a greater activation of the cDNA expressed DHEA ST when assayed with DHEA (2.5-fold) than when the same preparation was assayed with minoxidil (1.4-fold). These data indicate that DHEA ST catalyzes the sulfate conjugation of minoxidil: DHEA ST activity present in the human gut and liver would be expected to add to the overall sulfate conjugation of orally administered minoxidil. Thus, DHEA ST activity must be considered when determining the human tissue sulfotransferase contribution to minoxidil sulfation.
Phenol sulfotransferase pharmacogenetics in humans: association of common SULT1A1 alleles with TS PST phenotype
The phenol sulfotransferases (PSTs) catalyze the sulfation of both small planar phenols and phenolic monoamines. Three highly homologous PST genes, SULT1A1, SULT1A2, and SULT1A3, are known to exist in humans. The prototypic biochemical phenotype associated with the enzyme encoded by SULT1A1 is the thermal stable (TS) sulfation of 4 microM 4-nitrophenol (TS PST activity). Biochemical pharmacogenetic studies have demonstrated that individual variation in both TS PST activity and thermal stability in humans are inherited. As a step toward understanding molecular mechanisms responsible for the genetic regulation of PSTs in humans, we report here common SULT1A1 nucleotide polymorphisms that are associated with phenotypic variation in both platelet TS PST activity and thermal stability. When 905 human subjects were phenotyped for platelet TS PST activity and thermal stability, activity varied more than 50-fold, and thermal stability varied over 10-fold. DNA was isolated from the blood of 33 of these subjects selected on the basis of "extreme" TS PST phenotypes: high activity and high thermal stability; low activity and low thermal stability; or low activity and high thermal stability. These 33 subjects were genotyped for SULT1A1 by PCR amplification and sequencing of the entire open reading frame (ORF) as well as approximately 1 kb of intron DNA sequence. One common allele, SULT1A1*2, was uniformly associated with both very low TS PST activity and low thermal stability. The allele frequency of SULT1A1*2 in a randomly selected population sample of 150 Caucasian blood donors was 0.31 (31%), indicating that approximately 9% of this population would be homozygous for that allele.
Sulfation of minoxidil by multiple human cytosolic sulfotransferases
Minoxidil is an antihypertensive agent and hair growth promoter that is metabolized by sulfation to the active compound, minoxidil sulfate. Thermostable phenol sulfotransferase (TS PST or P-PST) was initially thought to catalyze the reaction, and the enzyme was designated minoxidil sulfotransferase (MNX-ST). Information about human ST activities toward minoxidil would be useful in developing the capacity to predict individual responses to minoxidil based on tissue levels of STs. Therefore, human STs were studied from platelet homogenates, partially purified platelets, scalp skin high speed supernatants and COS-1 cell cDNA expressed preparations using a radiochemical enzymatic assay with minoxidil as the substrate. Studies showed the presence of TS PST, TL (thermolabile) PST and MNX-ST activities in human scalp skin. Biochemical properties and correlation studies suggested that in addition to TS PST, the TL PST activity, another ST activity or both were involved in the reaction. Partially purified human platelet TL PST tested with minoxidil and dopamine showed identical thermal stabilities and similar responses to the inhibitors 2,6-dichloro-4-nitrophenol (DCNP) and NaCl. To characterize the activity of TL PST toward minoxidil, several biochemical properties of the enzyme expressed from a human liver cDNA clone were investigated. When assayed with minoxidil and dopamine, thermal stabilities of the expressed enzyme were identical and IC50 values for the inhibitors DCNP and NaCl were similar. It was also demonstrated that cDNA encoded human liver dehydroepiandrosterone sulfotransferase and estrogen sulfotransferase contributed to the sulfation of minoxidil. The results confirm that at least four human STs contribute to minoxidil sulfation. MNX-ST activity represents a combination of ST activities. The data indicate that multiple ST activities should be taken into account in attempts to predict the regulation of minoxidil sulfation and individual responses to minoxidil.
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