Genome-wide gene expression dataset used to identify potential therapeutic targets in androgenetic alopecia.
ABSTRACT: The microarray dataset attached to this report is related to the research article with the title: "A genomic approach to susceptibility and pathogenesis leads to identifying potential novel therapeutic targets in androgenetic alopecia" (Dey-Rao and Sinha, 2017) . Male-pattern hair loss that is induced by androgens (testosterone) in genetically predisposed individuals is known as androgenetic alopecia (AGA). The raw dataset is being made publicly available to enable critical and/or extended analyses. Our related research paper utilizes the attached raw dataset, for genome-wide gene-expression associated investigations. Combined with several in silico bioinformatics-based analyses we were able to delineate five strategic molecular elements as potential novel targets towards future AGA-therapy.
Project description:BACKGROUND: The functional polymorphism that explains the established association of the androgen receptor (AR) with androgenetic alopecia (AGA) remains unidentified, but Copy Number Variation (CNV) might be relevant. CNV involves changes in copy number of large segments of DNA, leading to the altered dosage of gene regulators or genes themselves. Two recent reports indicate regions of CNV in and around AR, and these have not been studied in relation to AGA. The aim of this preliminary case-control study was to determine if AR CNV is associated with AGA, with the hypothesis that CNV is the functional AR variant contributing to this condition. METHODOLOGY/PRINCIPAL FINDINGS: Multiplex Ligation-dependent Probe Amplification was used to screen for CNV in five AR exons and a conserved, non-coding region upstream of AR in 85 men carefully selected as cases and controls for maximal phenotypic contrast. There was no evidence of CNV in AR in any of the cases or controls, and thus no evidence of significant association between AGA and AR CNV. CONCLUSIONS/SIGNIFICANCE: The results suggest this form of genomic variation at the AR locus is unlikely to predispose to AGA.
Project description:Androgenetic alopecia (AGA), or male-pattern baldness, is the most common form of hair loss. Its pathogenesis is androgen dependent, and genetic predisposition is the major requirement for the phenotype. We demonstrate that genetic variability in the androgen receptor gene (AR) is the cardinal prerequisite for the development of early-onset AGA, with an etiological fraction of 0.46. The investigation of a large number of genetic variants covering the AR locus suggests that a polyglycine-encoding GGN repeat in exon 1 is a plausible candidate for conferring the functional effect. The X-chromosomal location of AR stresses the importance of the maternal line in the inheritance of AGA.
Project description:BACKGROUND: Androgenetic alopecia (AGA) is a well-characterized type of progressive hair loss commonly seen in men, with different prevalences in different ethnic populations. It is generally considered to be a polygenic heritable trait. Several susceptibility genes/loci, such as AR/EDA2R, HDAC9 and 20p11, have been identified as being involved in its development in European populations. In this study, we aim to validate whether these loci are also associated with AGA in the Chinese Han population. METHODS: We genotyped 16 previously reported single nucleotide polymorphisms (SNPs) with 445 AGA cases and 546 healthy controls using the Sequenom iPlex platform. The trend test was used to evaluate the association between these loci and AGA in the Chinese Han population. Conservatively accounting for multiple testing by the Bonferroni correction, the threshold for statistical significance was P ? 3.13 × 10(-3). RESULTS: We identified that 5 SNPs at 20p11 were significantly associated with AGA in the Chinese Han population (1.84 × 10(-11) ? P ? 2.10 × 10(-6)). CONCLUSIONS: This study validated, for the first time, that 20p11 also confers risk for AGA in the Chinese Han population and implicated the potential common genetic factors for AGA shared by both Chinese and European populations.
Project description:Testosterone is necessary for the development of male pattern baldness, known as androgenetic alopecia (AGA); yet, the mechanisms for decreased hair growth in this disorder are unclear. We show that prostaglandin D(2) synthase (PTGDS) is elevated at the mRNA and protein levels in bald scalp compared to haired scalp of men with AGA. The product of PTGDS enzyme activity, prostaglandin D(2) (PGD(2)), is similarly elevated in bald scalp. During normal follicle cycling in mice, Ptgds and PGD(2) levels increase immediately preceding the regression phase, suggesting an inhibitory effect on hair growth. We show that PGD(2) inhibits hair growth in explanted human hair follicles and when applied topically to mice. Hair growth inhibition requires the PGD(2) receptor G protein (heterotrimeric guanine nucleotide)-coupled receptor 44 (GPR44), but not the PGD(2) receptor 1 (PTGDR). Furthermore, we find that a transgenic mouse, K14-Ptgs2, which targets prostaglandin-endoperoxide synthase 2 expression to the skin, demonstrates elevated levels of PGD(2) in the skin and develops alopecia, follicular miniaturization, and sebaceous gland hyperplasia, which are all hallmarks of human AGA. These results define PGD(2) as an inhibitor of hair growth in AGA and suggest the PGD(2)-GPR44 pathway as a potential target for treatment.
Project description:Androgenetic alopecia (AGA, male pattern baldness) is the most common form of hair loss. The origin of AGA is genetic, with the X chromosome located androgen receptor gene (AR) being the only risk gene identified to date. We present the results of a genome-wide linkage study of 95 families and linkage fine mapping of the 3q21-q29, 11q14-q25, 18p11-q23, and 19p13-q13 regions in an extended sample of 125 families of German descent. The locus with strongest evidence for linkage was mapped to 3q26 with a nonparametric linkage (NPL) score of 3.97 (empirical p value = 0.00055). This is the first step toward the identification of new susceptibility genes in AGA, a process which will provide important insights into the molecular and cellular basis of scalp hair loss.
Project description:Hormonal and metabolic abnormalities have been reported in men with early-onset androgenetic alopecia (AGA). Although this has been ascribed to the existence of a male polycystic ovary syndrome (PCOS)-equivalent, data on this topic are inconsistent and this syndrome has not been already acknowledged. To evaluate if, already before the age of 35 years, any difference occurs in the glycolipid and hormonal profiles and in the body weight in men with AGA compared to age-matched controls, we performed a comprehensive meta-analysis of all the available observational case-control studies of literature, using MEDLINE, Google Schoolar and Scopus databases. Among 10596 papers retrieved, seven studies were finally included, enrolling a total of 1009 participants. Our findings demonstrate that young men with AGA have a slightly but significantly worse glycolipid profile compared to controls and a hormonal pattern resembling those of women with PCOS, already before the age of 35 years. Therefore, early-onset AGA might represent a phenotypic sign of the male PCOS-equivalent. The acknowledgement of this syndrome would be of importance to prevent the long-term consequences on health in the affected men. The glycolipid profile and the body weight should be monitored in men with AGA starting from the second decade of life.
Project description:Platelet-rich plasma (PRP) treatment has gained popularity among different surgical specialities for improving various conditions. Androgenetic alopecia (AGA) is a common disorder, with possible psychosocial implications. Plastic surgeons have increased the practice of PRP injections for hair restoration. A meta-analysis on this topic was performed comparing local injection of PRP versus control to investigate the efficacy of local PRP injections in AGA.We performed a systematic literature search. The increase in number of hairs was the primary outcome. Secondary outcomes were the increase of hair thickness and the percentage increase in hair number and thickness.Seven studies involving 194 patients were retrieved and included in the present analysis. A significantly locally increased hair number per cm2 was observed after PRP injections versus control (mean difference [MD] 14.38, 95% confidence interval [CI] 6.38-22.38, P < 0.001). Similarly, a significantly increased hair thickness cross-section per 10-4 mm2 (MD 0.22, 95% CI 0.07-0.38, P = 0.005) favoring PRP group. The pooled results did not show a significant percentage increase in hair number (MD 18.79%, 95% CI - 8.50-46.08, P = 0.18), neither hair thickness (MD 32.63%, 95% CI - 16.23-81.48, P = 0.19) among patients treated with PRP.Local injection of PRP for androgenic alopecia might be associated with an increased number of hairs in the treated areas with minimal morbidity, but there is clearly a lack of scientific evidence on this treatment modality. Further studies are needed to evaluate the efficacy of PRP for AGA.
Project description:Androgenetic alopecia (AGA) is a highly heritable condition and the most common form of hair loss in humans. Susceptibility loci have been described on the X chromosome and chromosome 20, but these loci explain a minority of its heritable variance. We conducted a large-scale meta-analysis of seven genome-wide association studies for early-onset AGA in 12,806 individuals of European ancestry. While replicating the two AGA loci on the X chromosome and chromosome 20, six novel susceptibility loci reached genome-wide significance (p?=?2.62×10??-1.01×10?¹²). Unexpectedly, we identified a risk allele at 17q21.31 that was recently associated with Parkinson's disease (PD) at a genome-wide significant level. We then tested the association between early-onset AGA and the risk of PD in a cross-sectional analysis of 568 PD cases and 7,664 controls. Early-onset AGA cases had significantly increased odds of subsequent PD (OR?=?1.28, 95% confidence interval: 1.06-1.55, p?=?8.9×10?³). Further, the AGA susceptibility alleles at the 17q21.31 locus are on the H1 haplotype, which is under negative selection in Europeans and has been linked to decreased fertility. Combining the risk alleles of six novel and two established susceptibility loci, we created a genotype risk score and tested its association with AGA in an additional sample. Individuals in the highest risk quartile of a genotype score had an approximately six-fold increased risk of early-onset AGA [odds ratio (OR)?=?5.78, p?=?1.4×10???]. Our results highlight unexpected associations between early-onset AGA, Parkinson's disease, and decreased fertility, providing important insights into the pathophysiology of these conditions.
Project description:Testosterone is necessary for the development of male pattern baldness, known as androgenetic alopecia (AGA); yet the mechanisms for decreased hair growth in this disorder are unclear. Here, we show that prostaglandin D2 synthase (PTGDS) is elevated at the mRNA and protein levels in bald scalp compared to haired scalp of men with AGA. The product of PTGDS enzyme activity, prostaglandin D2 (PGD2), is similarly elevated in bald scalp. During normal follicle cycling in mice Ptgds and PGD2 levels increase immediately preceding the regression phase, suggesting an inhibitory effect on hair growth. We show that PGD2 inhibits hair growth in explanted human hair follicles and when applied topically to mice. Hair growth inhibition requires the PGD2 receptor G protein-coupled receptor 44 (GPR44), but not the prostaglandin D2 receptor 1(PTGDR). Furthermore, we find that a transgenic mouse, K14-Ptgs2, which targets prostaglandin-endoperoxide synthase 2 expression to the skin, demonstrates elevated levels of PGD2 in the skin and develops alopecia, follicular miniaturization and sebaceous gland hyperplasia, which are all hallmarks of human AGA. These results define PGD2 as an inhibitor of hair growth in AGA and suggest the PGD2-GPR44 pathway as a potential target for treatment. 5 individuals with Androgenetic Alopecia were biopsied at both their haired and bald scalp for mRNA purification and microarray (total 10 arrays)
Project description:Androgenetic alopecia (AGA), also known as common baldness, is characterized by a marked decrease in hair follicle size, which could be related to the loss of hair follicle stem or progenitor cells. To test this hypothesis, we analyzed bald and non-bald scalp from AGA individuals for the presence of hair follicle stem and progenitor cells. Cells expressing cytokeratin15 (KRT15), CD200, CD34, and integrin, ?6 (ITGA6) were quantitated via flow cytometry. High levels of KRT15 expression correlated with stem cell properties of small cell size and quiescence. These KRT15(hi) stem cells were maintained in bald scalp samples. However, CD200(hi)ITGA6(hi) and CD34(hi) cell populations--which both possessed a progenitor phenotype, in that they localized closely to the stem cell-rich bulge area but were larger and more proliferative than the KRT15(hi) stem cells--were markedly diminished. In functional assays, analogous CD200(hi)Itga6(hi) cells from murine hair follicles were multipotent and generated new hair follicles in skin reconstitution assays. These findings support the notion that a defect in conversion of hair follicle stem cells to progenitor cells plays a role in the pathogenesis of AGA.