12 research outputs found
Genetic and Fetal Origins of Polycystic Ovary Syndrome
No full textPolycystic ovary syndrome (PCOS) is the most common endocrine disorder that affects women of reproductive age. Although the syndrome affects over 10 percent women worldwide, its cause(s) remains unknown. Numerous studies have focussed on the genetic and fetal origins of the syndrome. However, the outcomes of genome wide association studies and candidate gene studies towards defining PCOS have, arguably, had almost no impact on the definition, diagnosis and treatment of the syndrome. This could be attributed mainly to the divergence of PCOS studies, as these studies have not collectively defined the molecular mechanisms involved in PCOS phenotypes observed. This thesis examined the role of genes in loci associated with PCOS and TGFβ signalling molecules, as well as their upstream regulators and mechanisms in the pathogenesis of PCOS. Genes in loci associated with PCOS (candidate genes) were shown to be dynamically expressed during bovine fetal ovary development. Notably, those genes expressed during the early stages of fetal development such as C8H9orf3, TOX3, FBN3, GATA4, HMGA2 and DENND1A are co-expressed with genes involved in mitochondria function and are regulated upstream by DAP3, MYC, PTEN, HNF4A, ESRRA/G, PSEN1, MYC, mitochondrial LONP1 and TP53. Those expressed in the second trimester or just after mid gestation such as YAP1, INSR, THADA and TGFB1I1 were co-expressed with genes involved in stroma expansion and are regulated upstream by TGF-β signalling molecules including TGFB1, TGFB2, TGFB3 and TGFBR2, coagulation factor II and fibroblast proliferation regulators including FGF2. Candidate genes expressed during the third trimester such as FDFT1, LHCGR, AMH, FSHR, ZBTB16 and PLGRKT are co-expressed with genes involved with folliculogenesis and steroidogenesis and are regulated upstream by SREBF2, INSIGI, TGFB1 and RPTOR among others. Thus, this study infers the possible role of these canonical pathways and upstream regulators in the pathogenesis of PCOS during fetal ovary development. The role of TGFB signalling molecules in the aetiology of PCOS was further examined. These molecules were also found to be dynamically expressed during fetal ovary development and could regulate some PCOS candidate genes in bovine fetal ovary fibroblasts. Across gestation, LTBP1/2/3/4, FBN1, TGFB2/3, TGFBR2/3 and TGFB1I1 expression levels increased, while FBN3, TGFBR3L, TGFBI and TGFB1 decreased and TGFBRAP1, TGFBR1 and FBN2 remained relatively constant. TGFβ1, but not androgens nor AMH, has previously been shown to inhibit expression of candidate genes (AR, INSR, C8H9orf3 and RAD50) but stimulate expression of androgen receptor co-factor, TGFB1I1, in cultured fetal ovarian fibroblasts. Additionally, we showed that expression of PCOS candidate genes ERBB3, NEIL2, IRF1 and ZBTB16 significantly decreased after TGFβ1 treatment in cultured fetal ovarian fibroblasts. These findings further confirm that TGFβ signalling could be involved in the pathogenesis of PCOS or at least in the establishment of polycystic ovaries. The role of candidate genes and TGFβ signalling molecules in various tissues including nonovarian tissues was assessed as PCOS does not only affect the ovary. Both were shown to be dynamically expressed in gonadal (ovary and testis), metabolic (heart, liver and kidney) and brain (brain and cerebellum) tissues during the first half of human fetal development and postnatally until adulthood. More so, some genes were significantly expressed in specific tissues at different time points pre-natally and/or post-natally. Notably, HMGA2, FBN3 and TOX3 were highly expressed during the early stages of fetal development in all tissues but least during adulthood. DENND1A, THADA, MAPRE1, RAB5B, ARL14EP, KRR1, NEIL2 and RAD50 were dynamically expressed in all postnatal tissues studied. Interestingly, correlation between expression of HMGA2/YAP1 and RAD50/YAP1 were significant in at least 5 of the 7 fetal tissues studied. Furthermore, HMGA2, YAP1 and RAD50 correlated significantly with most TGFβ signalling molecules in at least 4 tissues. We further showed that there is certainly a crosstalk within and between PCOS candidate genes and TGFβ signalling molecules during fetal development within each tissue. Considering the fact that HMGA2 and YAP1 are involved in the Hippo signalling pathway as well as epithelial mesenchymal transition (EMT) during embryogenesis through TGFβ signalling, their role in the aetiology of PCOS requires further studies. In conclusion, these findings confirm that genes in loci associated with PCOS and TGFβ signalling molecules are actively involved in the genetic and fetal origins of the syndrome and that there is a possible crosstalk between both in the development of multiple organs. This also infers that dysregulation of PCOS candidate genes and TGFβ signalling molecules during fetal development could initiate/lead to a cascade of molecular events in various tissues accounting for the various phenotypes of PCOS observed in adulthood.Thesis (Ph.D.) -- University of Adelaide, School of Biomedicine, 202
Table_2_Genes in loci genetically associated with polycystic ovary syndrome are dynamically expressed in human fetal gonadal, metabolic and brain tissues.pdf
No full textBackgroundPolycystic ovary syndrome (PCOS) is a heterogeneous disorder, affecting around 10% of women of reproductive age, with infertility, depression or anxiety, obesity, insulin resistance and type 2 diabetes as risk factors. The cause of PCOS is not known but there is a predisposition to developing PCOS in adult life that arises during fetal or perinatal life. PCOS also has a genetic predisposition and a number of genetic loci associated with PCOS have been identified. These loci contain 25 candidate genes which are currently being studied to define the syndrome. Although the name PCOS suggests a syndrome of the ovary, PCOS has also been associated with the central nervous system and other organ systems in the body due to the wide variety of symptoms it presents.MethodsHere, we examined the expression patterns of PCOS candidate genes in gonadal (ovary and testis), metabolic (heart, liver and kidney) and brain (brain and cerebellum) tissues during the first half of human fetal development and postnatally until adulthood using public RNA sequencing data. This study is an initial step for more comprehensive and translational studies to define PCOS.ResultsWe found that the genes were dynamically expressed in the fetal tissues studied. Some genes were significantly expressed in gonadal tissues, whilst others were expressed in metabolic or brain tissues at different time points prenatally and/or postnatally. HMGA2, FBN3 and TOX3 were highly expressed during the early stages of fetal development in all tissues but least during adulthood. Interestingly, correlation between expression of HMGA2/YAP1 and RAD50/YAP1 were significant in at least 5 of the 7 fetal tissues studied. Notably, DENND1A, THADA, MAPRE1, RAB5B, ARL14EP, KRR1, NEIL2 and RAD50 were dynamically expressed in all postnatal tissues studied.ConclusionsThese findings suggest that these genes have tissue- or development-specific roles in multiple organs, possibly resulting in the various symptoms associated with PCOS. Thus the fetal origin of a predisposition to PCOS in adulthood could arise via the effects of PCOS candidate genes in the development of multiple organs.</p
Expression of transforming growth factor β signalling molecules and their correlations with genes in loci linked to polycystic ovary syndrome in human foetal and adult tissues
No full textContextAltered signalling of androgens, anti-Müllerian hormone or transforming growth factor beta (TGFβ) during foetal development have been implicated in the predisposition to polycystic ovary syndrome (PCOS) in later life, aside from its genetic predisposition. In foetal ovarian fibroblasts, TGFβ1 has been shown to regulate androgen signalling and seven genes located in loci associated with PCOS. Since PCOS exhibits a myriad of symptoms, it likely involves many different organs.AimsTo identify the relationships between TGFβ signalling molecules and PCOS candidate genes in different tissues associated with PCOS.MethodsUsing RNA sequencing data, we examined the expression patterns of TGFβ signalling molecules in the human ovary, testis, heart, liver, kidney, brain tissue, and cerebellum from 4 to 20 weeks of gestation and postnatally. We also examined the correlations between gene expression of TGFβ signalling molecules and PCOS candidate genes.Key resultsTGFβ signalling molecules were dynamically expressed in most tissues prenatally and/or postnatally. FBN3, a PCOS candidate gene involved in TGFβ signalling, was expressed during foetal development in all tissues. The PCOS candidate genes HMGA2, YAP1, and RAD50 correlated significantly (P < 0.01) with most TGFβ signalling molecules in at least four foetal tissues, and specifically with TGFBR1 in six out of the seven tissues examined.ConclusionsThis study suggests that possible crosstalk occurs between genes in loci associated with PCOS and TGFβ signalling molecules in multiple tissues, particularly during foetal development.ImplicationsThus, alteration in TGFβ signalling during foetal development could affect many tissues contributing to the multiple phenotypes of PCOS in later life
Genes in loci genetically associated with polycystic ovary syndrome are dynamically expressed in human fetal gonadal, metabolic and brain tissues
No full textBackground: Polycystic ovary syndrome (PCOS) is a heterogeneous disorder, affecting around 10% of women of reproductive age, with infertility, depression or anxiety, obesity, insulin resistance and type 2 diabetes as risk factors. The cause of PCOS is not known but there is a predisposition to developing PCOS in adult life that arises during fetal or perinatal life. PCOS also has a genetic predisposition and a number of genetic loci associated with PCOS have been identified. These loci contain 25 candidate genes which are currently being studied to define the syndrome. Although the name PCOS suggests a syndrome of the ovary, PCOS has also been associated with the central nervous system and other organ systems in the body due to the wide variety of symptoms it presents.Methods: Here, we examined the expression patterns of PCOS candidate genes in gonadal (ovary and testis), metabolic (heart, liver and kidney) and brain (brain and cerebellum) tissues during the first half of human fetal development and postnatally until adulthood using public RNA sequencing data. This study is an initial step for more comprehensive and translational studies to define PCOS.Results: We found that the genes were dynamically expressed in the fetal tissues studied. Some genes were significantly expressed in gonadal tissues, whilst others were expressed in metabolic or brain tissues at different time points prenatally and/or postnatally. HMGA2, FBN3 and TOX3 were highly expressed during the early stages of fetal development in all tissues but least during adulthood. Interestingly, correlation between expression of HMGA2/YAP1 and RAD50/YAP1 were significant in at least 5 of the 7 fetal tissues studied. Notably, DENND1A, THADA, MAPRE1, RAB5B, ARL14EP, KRR1, NEIL2 and RAD50 were dynamically expressed in all postnatal tissues studied.Conclusions: These findings suggest that these genes have tissue- or development-specific roles in multiple organs, possibly resulting in the various symptoms associated with PCOS. Thus the fetal origin of a predisposition to PCOS in adulthood could arise via the effects of PCOS candidate genes in the development of multiple organs
Candidate genes for polycystic ovary syndrome are regulated by TGFβ in the bovine foetal ovary
No full textSTUDY QUESTION: Could changes in transforming growth factor β (TGFβ) signalling during foetal ovary development alter the expression of polycystic ovary syndrome (PCOS) candidate genes leading to a predisposition to PCOS? SUMMARY ANSWER: TGFβ signalling molecules are dynamically expressed during foetal ovary development and TGFβ1 inhibits expression of the androgen receptor (AR) and 7 (INSR, C8H9orf3, RAD50, ERBB3, NEIL2, IRF1 and ZBTB16) of the 25 PCOS candidate genes in foetal ovarian fibroblasts in vitro, whilst increasing expression of the AR cofactor TGFβ-induced transcript 1 (TGFB1I1 or Hic5). WHAT IS KNOWN ALREADY: The ovarian stroma arises from the mesonephros during foetal ovary development. Changes in the morphology of the ovarian stroma are cardinal features of PCOS. The ovary is more fibrous and has more tunica and cortical and subcortical stroma. It is not known why this is and when this arises. PCOS has a foetal origin and perhaps ovarian stroma development is altered during foetal life to determine the formation of a polycystic ovary later in life. PCOS also has a genetic origin with 19 loci containing 25 PCOS candidate genes. In many adult tissues, TGFβ is known to stimulate fibroblast replication and collagen deposition in stroma, though it has the opposite effect in the non-scaring foetal tissues. Our previous studies showed that TGFβ signalling molecules [TGFβs and their receptors, latent TGFβ binding proteins (LTBPs) and fibrillins, which are extracellular matrix proteins that bind LTBPs] are expressed in foetal ovaries. Also, we previously showed that TGFβ1 inhibited expression of AR and 3 PCOS candidate genes (INSR, C8H9orf3 and RAD50) and stimulated expression of TGFB1I1 in cultured foetal ovarian fibroblasts. STUDY DESIGN, SIZE, DURATION: We used Bos taurus for this study as we can ethically collect foetal ovaries from across the full 9-month gestational period. Foetal ovaries (62–276 days, n = 19) from across gestation were collected from pregnant B. taurus cows for RNA-sequencing (RNA-seq) analyses. Foetal ovaries from B. taurus cows were collected (160–198 days, n = 6) for culture of ovarian fibroblasts. PARTICIPANTS/MATERIALS, SETTING, METHODS: RNA-seq transcriptome profiling was performed on foetal ovaries and the data on genes involved in TGFβ signalling were extracted. Cells were dispersed from foetal ovaries and fibroblasts cultured and treated with TGFβ1. The effects of TGFβ regulation on the remaining eight PCOS candidate genes not previously studied (ERBB3, MAPRE1, FDFT1, NEIL2, ARL14EP, PLGRKT, IRF1 and ZBTB16) were examined. MAIN RESULTS AND THE ROLE OF CHANCE: Many TGFβ signalling molecules are expressed in the foetal ovary, and for most, their expression levels increased accross gestation (LTBP1/2/3/4, FBN1, TGFB2/3, TGFBR2/3 and TGFB1I1), while a few decreased (FBN3, TGFBR3L, TGFBI and TGFB1) and others remained relatively constant (TGFBRAP1, TGFBR1 and FBN2). TGFβ1 significantly decreased expression of PCOS candidate genes ERBB3, NEIL2, IRF1 and ZBTB16 in cultured foetal ovarian fibroblasts. LARGE SCALE DATA: The FASTQ files, normalized data and experimental information have been deposited in the Gene Expression Omnibus (GEO) accessible by accession number GSE178450. LIMITATIONS, REASONS FOR CAUTION: Regulation of PCOS candidate genes by TGFβ was carried out in vitro and further studies in vivo are required. This study was carried out in bovine where foetal ovaries from across all of the 9-month gestational period were available, unlike in the human where it is not ethically possible to obtain ovaries from the second half of gestation. WIDER IMPLICATIONS OF THE FINDINGS: From our current and previous results we speculate that inhibition of TGFβ signalling in the foetal ovary is likely to (i) increase androgen sensitivity by enhancing expression of AR, (ii) increase stromal activity by stimulating expression of COL1A1 and COL3A1 and (iii) increase the expression of 7 of the 25 PCOS candidate genes. Thus inhibition of TGFβ signalling could be part of the aetiology of PCOS or at least the aetiology of polycystic ovaries. STUDY FUNDING/COMPETING INTEREST(S): Funding was received from Adelaide University China Fee Scholarship (M.L.), Australian Research Training Program (R.A.) and the Faculty of Health and Medical Science Divisional Scholarship (R.A.), Adelaide Graduate Research Scholarships (R.A. and N.A.B.), Australia Awards Scholarship (M.D.H.), Robinson Research Institute Career Development Fellowship (K.H.) and Building On Ideas Grant (K.H.), National Health and Medical Research Council of Australia Centre for Research Excellence in the Evaluation, Management and Health Care Needs of Polycystic Ovary Syndrome (N.A.B., M.D.H. and R.J.R.; GTN1078444) and the Centre for Research Excellence on Women’s Health in Reproductive life (R.A., R.J.R. and K.H.; GTN1171592) and the UK Medical Research Council (R.A.A.; grant no. G1100357). The funders did not play any role in the study design, data collection and analysis, decision to publish or preparation of the manuscript. The authors of this manuscript have nothing to declare and no conflict of interest that could be perceived as prejudicing the impartiality of the research reported
Table_1_Genes in loci genetically associated with polycystic ovary syndrome are dynamically expressed in human fetal gonadal, metabolic and brain tissues.xlsx
No full textBackgroundPolycystic ovary syndrome (PCOS) is a heterogeneous disorder, affecting around 10% of women of reproductive age, with infertility, depression or anxiety, obesity, insulin resistance and type 2 diabetes as risk factors. The cause of PCOS is not known but there is a predisposition to developing PCOS in adult life that arises during fetal or perinatal life. PCOS also has a genetic predisposition and a number of genetic loci associated with PCOS have been identified. These loci contain 25 candidate genes which are currently being studied to define the syndrome. Although the name PCOS suggests a syndrome of the ovary, PCOS has also been associated with the central nervous system and other organ systems in the body due to the wide variety of symptoms it presents.MethodsHere, we examined the expression patterns of PCOS candidate genes in gonadal (ovary and testis), metabolic (heart, liver and kidney) and brain (brain and cerebellum) tissues during the first half of human fetal development and postnatally until adulthood using public RNA sequencing data. This study is an initial step for more comprehensive and translational studies to define PCOS.ResultsWe found that the genes were dynamically expressed in the fetal tissues studied. Some genes were significantly expressed in gonadal tissues, whilst others were expressed in metabolic or brain tissues at different time points prenatally and/or postnatally. HMGA2, FBN3 and TOX3 were highly expressed during the early stages of fetal development in all tissues but least during adulthood. Interestingly, correlation between expression of HMGA2/YAP1 and RAD50/YAP1 were significant in at least 5 of the 7 fetal tissues studied. Notably, DENND1A, THADA, MAPRE1, RAB5B, ARL14EP, KRR1, NEIL2 and RAD50 were dynamically expressed in all postnatal tissues studied.ConclusionsThese findings suggest that these genes have tissue- or development-specific roles in multiple organs, possibly resulting in the various symptoms associated with PCOS. Thus the fetal origin of a predisposition to PCOS in adulthood could arise via the effects of PCOS candidate genes in the development of multiple organs.</p
Presentation_1_Genes in loci genetically associated with polycystic ovary syndrome are dynamically expressed in human fetal gonadal, metabolic and brain tissues.pdf
No full textBackgroundPolycystic ovary syndrome (PCOS) is a heterogeneous disorder, affecting around 10% of women of reproductive age, with infertility, depression or anxiety, obesity, insulin resistance and type 2 diabetes as risk factors. The cause of PCOS is not known but there is a predisposition to developing PCOS in adult life that arises during fetal or perinatal life. PCOS also has a genetic predisposition and a number of genetic loci associated with PCOS have been identified. These loci contain 25 candidate genes which are currently being studied to define the syndrome. Although the name PCOS suggests a syndrome of the ovary, PCOS has also been associated with the central nervous system and other organ systems in the body due to the wide variety of symptoms it presents.MethodsHere, we examined the expression patterns of PCOS candidate genes in gonadal (ovary and testis), metabolic (heart, liver and kidney) and brain (brain and cerebellum) tissues during the first half of human fetal development and postnatally until adulthood using public RNA sequencing data. This study is an initial step for more comprehensive and translational studies to define PCOS.ResultsWe found that the genes were dynamically expressed in the fetal tissues studied. Some genes were significantly expressed in gonadal tissues, whilst others were expressed in metabolic or brain tissues at different time points prenatally and/or postnatally. HMGA2, FBN3 and TOX3 were highly expressed during the early stages of fetal development in all tissues but least during adulthood. Interestingly, correlation between expression of HMGA2/YAP1 and RAD50/YAP1 were significant in at least 5 of the 7 fetal tissues studied. Notably, DENND1A, THADA, MAPRE1, RAB5B, ARL14EP, KRR1, NEIL2 and RAD50 were dynamically expressed in all postnatal tissues studied.ConclusionsThese findings suggest that these genes have tissue- or development-specific roles in multiple organs, possibly resulting in the various symptoms associated with PCOS. Thus the fetal origin of a predisposition to PCOS in adulthood could arise via the effects of PCOS candidate genes in the development of multiple organs.</p
DataSheet1_Analysis of Upstream Regulators, Networks, and Pathways Associated With the Expression Patterns of Polycystic Ovary Syndrome Candidate Genes During Fetal Ovary Development.PDF
No full textPolycystic Ovary Syndrome (PCOS) is a multifactorial syndrome with reproductive, endocrine, and metabolic symptoms, affecting about 10% women of reproductive age. Pathogenesis of the syndrome is poorly understood with genetic and fetal origins being the focus of the conundrum. Genetic predisposition of PCOS has been confirmed by candidate gene studies and Genome-Wide Association Studies (GWAS). Recently, the expression of PCOS candidate genes across gestation has been studied in human and bovine fetal ovaries. The current study sought to identify potential upstream regulators and mechanisms associated with PCOS candidate genes. Using RNA sequencing data of bovine fetal ovaries (62–276 days, n = 19), expression of PCOS candidate genes across gestation was analysed using Partek Flow. A supervised heatmap of the expression data of all 24,889 genes across gestation was generated. Most of the PCOS genes fell into one of four clusters according to their expression patterns. Some genes correlated negatively (early genes; C8H9orf3, TOX3, FBN3, GATA4, HMGA2, and DENND1A) and others positively (late genes; FDFT1, LHCGR, AMH, FSHR, ZBTB16, and PLGRKT) with gestational age. Pathways associated with PCOS candidate genes and genes co-expressed with them were determined using Ingenuity pathway analysis (IPA) software as well as DAVID Bioinformatics Resources for KEGG pathway analysis and Gene Ontology databases. Genes expressed in the early cluster were mainly involved in mitochondrial function and oxidative phosphorylation and their upstream regulators included PTEN, ESRRG/A and MYC. Genes in the late cluster were involved in stromal expansion, cholesterol biosynthesis and steroidogenesis and their upstream regulators included TGFB1/2/3, TNF, ERBB2/3, VEGF, INSIG1, POR, and IL25. These findings provide insight into ovarian development of relevance to the origins of PCOS, and suggest that multiple aetiological pathways might exist for the development of PCOS.</p
DataSheet2_Analysis of Upstream Regulators, Networks, and Pathways Associated With the Expression Patterns of Polycystic Ovary Syndrome Candidate Genes During Fetal Ovary Development.PDF
No full textPolycystic Ovary Syndrome (PCOS) is a multifactorial syndrome with reproductive, endocrine, and metabolic symptoms, affecting about 10% women of reproductive age. Pathogenesis of the syndrome is poorly understood with genetic and fetal origins being the focus of the conundrum. Genetic predisposition of PCOS has been confirmed by candidate gene studies and Genome-Wide Association Studies (GWAS). Recently, the expression of PCOS candidate genes across gestation has been studied in human and bovine fetal ovaries. The current study sought to identify potential upstream regulators and mechanisms associated with PCOS candidate genes. Using RNA sequencing data of bovine fetal ovaries (62–276 days, n = 19), expression of PCOS candidate genes across gestation was analysed using Partek Flow. A supervised heatmap of the expression data of all 24,889 genes across gestation was generated. Most of the PCOS genes fell into one of four clusters according to their expression patterns. Some genes correlated negatively (early genes; C8H9orf3, TOX3, FBN3, GATA4, HMGA2, and DENND1A) and others positively (late genes; FDFT1, LHCGR, AMH, FSHR, ZBTB16, and PLGRKT) with gestational age. Pathways associated with PCOS candidate genes and genes co-expressed with them were determined using Ingenuity pathway analysis (IPA) software as well as DAVID Bioinformatics Resources for KEGG pathway analysis and Gene Ontology databases. Genes expressed in the early cluster were mainly involved in mitochondrial function and oxidative phosphorylation and their upstream regulators included PTEN, ESRRG/A and MYC. Genes in the late cluster were involved in stromal expansion, cholesterol biosynthesis and steroidogenesis and their upstream regulators included TGFB1/2/3, TNF, ERBB2/3, VEGF, INSIG1, POR, and IL25. These findings provide insight into ovarian development of relevance to the origins of PCOS, and suggest that multiple aetiological pathways might exist for the development of PCOS.</p
Analysis of upstream regulators, networks and pathways associated with the expression patterns of polycystic ovary syndrome candidate genes during fetal ovary development
No full textPolycystic Ovary Syndrome (PCOS) is a multifactorial syndrome with reproductive, endocrine, and metabolic symptoms, affecting about 10% women of reproductive age. Pathogenesis of the syndrome is poorly understood with genetic and fetal origins being the focus of the conundrum. Genetic predisposition of PCOS has been confirmed by candidate gene studies and Genome-Wide Association Studies (GWAS). Recently, the expression of PCOS candidate genes across gestation has been studied in human and bovine fetal ovaries. The current study sought to identify potential upstream regulators and mechanisms associated with PCOS candidate genes. Using RNA sequencing data of bovine fetal ovaries (62-276 days, n = 19), expression of PCOS candidate genes across gestation was analysed using Partek Flow. A supervised heatmap of the expression data of all 24,889 genes across gestation was generated. Most of the PCOS genes fell into one of four clusters according to their expression patterns. Some genes correlated negatively (early genes; C8H9orf3, TOX3, FBN3, GATA4, HMGA2, and DENND1A) and others positively (late genes; FDFT1, LHCGR, AMH, FSHR, ZBTB16, and PLGRKT) with gestational age. Pathways associated with PCOS candidate genes and genes co-expressed with them were determined using Ingenuity pathway analysis (IPA) software as well as DAVID Bioinformatics Resources for KEGG pathway analysis and Gene Ontology databases. Genes expressed in the early cluster were mainly involved in mitochondrial function and oxidative phosphorylation and their upstream regulators included PTEN, ESRRG/A and MYC. Genes in the late cluster were involved in stromal expansion, cholesterol biosynthesis and steroidogenesis and their upstream regulators included TGFB1/2/3, TNF, ERBB2/3, VEGF, INSIG1, POR, and IL25. These findings provide insight into ovarian development of relevance to the origins of PCOS, and suggest that multiple aetiological pathways might exist for the development of PCOS. </p
