Polycystic ovary syndrome (PCOS) is the leading endocrinopathy and the most common cause of anovulatory infertility, affecting 5-10% of women of reproductive age worldwide. PCOS is a polygenic heterogeneous disorder characterized by clinical and/or biochemical evidence of hyperandrogenism, chronic oligo- or anovulation, and polycystic-appearing ovaries. Women with untreated PCOS face an increased risk of visceral obesity, type 2 diabetes mellitus (T2DM), cardiovascular diseases (CVDs), hypertension, anxiety and depression, hormone-dependent cancers, and fertility problems. Although the etiology of PCOS is unclear, studies suggest several predisposing factors, including genetic susceptibility, epigenetic erosions, endocrine disruptions, and environmental and lifestyle factors.
PCOS has a strong heritable component. Male as well as female relatives of women with PCOS are at an increased risk of developing PCOS-associated reproductive and metabolic disorders. In a monozygotic twin study, the heritability of PCOS has been estimated to be ~ 70%. Thus, some genetic alterations seem to be involved in the pathogenesis of PCOS. However, human PCOS susceptibility loci identified by genome-wide association studies (GWAS) account for less than 10% of heritability. Hence, environmental and epigenetic mechanisms in which these genes are transcriptionally and post-transcriptionally regulated may play a key role in the etiology and pathophysiology of this disease. The functional characteristics of a PCOS loci locus include the epigenetic regulation of expression, DNA methylation or histone modification, enhancer-binding activity, transcription factor binding profiles, promoter activity, and the gene expression profile.
Significant epigenetic and transcriptomic differences in blood, serum, adipose tissue, oocytes, follicular fluid, and also skeletal muscle have been shown between women with and without PCOS, which may be part of the pathophysiology. These changes indicate that tissue-specific DNA methylation patterns likely contribute to changes in gene expression profiles that delineate tissue function and may contribute to PCOS development and related comorbidities. However, functional studies investigating the role of DNA methylation in women with PCOS are missing. This Research Topic will uncover the role of DNA methylation in the pathogenesis of PCOS.
Changes in DNA methylation of specific genes and promoter regions are closely related to PCOS development and progression of insulin resistance, hyperandrogenism, chronic anovulation, obesity, and other endocrine and metabolic disturbances. However, global DNA methylation patterns in PCOS are poorly understood and controversial. Besides altered DNA methylation, disruption in non-coding RNAs (ncRNAs) and miRNA expression is related to PCOS and its associated comorbidities. This Research Topic aims to provide updated information on the associated ncRNAs and miRNAs as potential epigenetic marks of PCOS for the treatment of associated comorbidities and improvement in the quality of life of women with PCOS.
Some epigenetic markers have also been detected in their ovary and follicular fluid. DNA methylome profiling of oocytes, granulosa, and theca cells, and follicular fluid reveals altered methylation in genes regulating vital ovarian functions in PCOS. For instance, the DENND1A (DENN/ MADD domain containing 1A) is overexpressed in theca cells of women with PCOS and is responsible for increased synthesis of androgen and progestin. Aberrant epigenetic changes have been observed in HOXA family genes in cumulus cells of patients with PCOS. In this Research Topic, we will discuss epigenetic markers in the reproductive system of PCOS patients.
Aberrant epigenetic reprogramming in PCOS patients might be triggered by adverse metabolic and hormonal intrauterine dysfunctions or postnatal environmental elements such as diet and obesity. Genome-wide DNA methylation analyses in visceral adipose tissue from rhesus monkeys of first-generation female offspring demonstrate significant changes in DNA methylation, suggesting that maternal androgen excess affects the intrauterine environment and may alter the epigenome and predispose to PCOS. Androgen excess during prenatal life leads to DNA hypomethylation in androgenized rats at specific CpG sites from the promoter region of GATA6 (-520) and STAR (-822) genes involved in steroidogenesis and steroid biosynthesis. In addition to the influence of androgens, other external factors may alter the epigenetic landscape, thus leading to PCOS.
This Research Topic highlights the disruption of epigenetic control of gene expression in PCOS patients through embryonic development, postnatal life, and adulthood.
Polycystic ovary syndrome (PCOS) is the leading endocrinopathy and the most common cause of anovulatory infertility, affecting 5-10% of women of reproductive age worldwide. PCOS is a polygenic heterogeneous disorder characterized by clinical and/or biochemical evidence of hyperandrogenism, chronic oligo- or anovulation, and polycystic-appearing ovaries. Women with untreated PCOS face an increased risk of visceral obesity, type 2 diabetes mellitus (T2DM), cardiovascular diseases (CVDs), hypertension, anxiety and depression, hormone-dependent cancers, and fertility problems. Although the etiology of PCOS is unclear, studies suggest several predisposing factors, including genetic susceptibility, epigenetic erosions, endocrine disruptions, and environmental and lifestyle factors.
PCOS has a strong heritable component. Male as well as female relatives of women with PCOS are at an increased risk of developing PCOS-associated reproductive and metabolic disorders. In a monozygotic twin study, the heritability of PCOS has been estimated to be ~ 70%. Thus, some genetic alterations seem to be involved in the pathogenesis of PCOS. However, human PCOS susceptibility loci identified by genome-wide association studies (GWAS) account for less than 10% of heritability. Hence, environmental and epigenetic mechanisms in which these genes are transcriptionally and post-transcriptionally regulated may play a key role in the etiology and pathophysiology of this disease. The functional characteristics of a PCOS loci locus include the epigenetic regulation of expression, DNA methylation or histone modification, enhancer-binding activity, transcription factor binding profiles, promoter activity, and the gene expression profile.
Significant epigenetic and transcriptomic differences in blood, serum, adipose tissue, oocytes, follicular fluid, and also skeletal muscle have been shown between women with and without PCOS, which may be part of the pathophysiology. These changes indicate that tissue-specific DNA methylation patterns likely contribute to changes in gene expression profiles that delineate tissue function and may contribute to PCOS development and related comorbidities. However, functional studies investigating the role of DNA methylation in women with PCOS are missing. This Research Topic will uncover the role of DNA methylation in the pathogenesis of PCOS.
Changes in DNA methylation of specific genes and promoter regions are closely related to PCOS development and progression of insulin resistance, hyperandrogenism, chronic anovulation, obesity, and other endocrine and metabolic disturbances. However, global DNA methylation patterns in PCOS are poorly understood and controversial. Besides altered DNA methylation, disruption in non-coding RNAs (ncRNAs) and miRNA expression is related to PCOS and its associated comorbidities. This Research Topic aims to provide updated information on the associated ncRNAs and miRNAs as potential epigenetic marks of PCOS for the treatment of associated comorbidities and improvement in the quality of life of women with PCOS.
Some epigenetic markers have also been detected in their ovary and follicular fluid. DNA methylome profiling of oocytes, granulosa, and theca cells, and follicular fluid reveals altered methylation in genes regulating vital ovarian functions in PCOS. For instance, the DENND1A (DENN/ MADD domain containing 1A) is overexpressed in theca cells of women with PCOS and is responsible for increased synthesis of androgen and progestin. Aberrant epigenetic changes have been observed in HOXA family genes in cumulus cells of patients with PCOS. In this Research Topic, we will discuss epigenetic markers in the reproductive system of PCOS patients.
Aberrant epigenetic reprogramming in PCOS patients might be triggered by adverse metabolic and hormonal intrauterine dysfunctions or postnatal environmental elements such as diet and obesity. Genome-wide DNA methylation analyses in visceral adipose tissue from rhesus monkeys of first-generation female offspring demonstrate significant changes in DNA methylation, suggesting that maternal androgen excess affects the intrauterine environment and may alter the epigenome and predispose to PCOS. Androgen excess during prenatal life leads to DNA hypomethylation in androgenized rats at specific CpG sites from the promoter region of GATA6 (-520) and STAR (-822) genes involved in steroidogenesis and steroid biosynthesis. In addition to the influence of androgens, other external factors may alter the epigenetic landscape, thus leading to PCOS.
This Research Topic highlights the disruption of epigenetic control of gene expression in PCOS patients through embryonic development, postnatal life, and adulthood.
