Androgen Receptor in the Ovary Theca Cells Plays a Critical Role in Androgen-Induced Reproductive Dysfunction

Paxillin regulates androgen receptor expression associated with granulosa cell focal adhesions

Paxillin is a ubiquitously expressed adaptor protein integral to focal adhesions, cell motility, and apoptosis. Paxillin has also recently been implicated as a mediator of nongenomic androgen receptor (AR) signaling in prostate cancer and other cells. We sought to investigate the relationship between paxillin and AR in granulosa cells (GCs), where androgen actions, apoptosis, and focal adhesions are of known importance, but where the role of paxillin is understudied. We recently showed that paxillin knockout in mouse GCs increases fertility in older mice. Here, we demonstrate that paxillin knockdown in human granulosa-derived KGN cells, as well as knockout in mouse primary GCs, results in reduced AR protein but not reduced mRNA expression. Further, we find that both AR protein and mRNA half-lives are reduced by approximately one-third in the absence of paxillin, but that cells adapt to chronic loss of paxillin by upregulating AR gene expression. Using co-immunofluorescence and proximity ligation assays, we show that paxillin and AR co-localize at the plasma membrane in GCs in a focal adhesion kinase-dependent way, and that disruption of focal adhesions leads to reduced AR protein level. Our findings suggest that paxillin recruits AR to the GC membrane, where it may be sequestered from proteasomal degradation and poised for nongenomic signaling, as reported in other tissues. To investigate the physiological significance of this in disorders of androgen excess, we tested the effect of GC-specific paxillin knockout in a mouse model of polycystic ovary syndrome (PCOS) induced by chronic postnatal dihydrotestosterone (DHT) exposure. While none of the control mice had estrous cycles, 33% of paxillin knockout mice were cycling, indicating that paxillin deletion may offer partial protection from the negative effects of androgen excess by reducing AR expression. Paxillin-knockout GCs from mice with DHT-induced PCOS also produced more estradiol than GCs from littermate controls. Thus, paxillin may be a novel target in the management of androgen-related disorders in women, such as PCOS.

Androgen excess: a hallmark of polycystic ovary syndrome

Polycystic ovarian syndrome (PCOS) is a metabolic, reproductive, and psychological disorder affecting 6-20% of reproductive women worldwide. However, there is still no cure for PCOS, and current treatments primarily alleviate its symptoms due to a poor understanding of its etiology. Compelling evidence suggests that hyperandrogenism is not just a primary feature of PCOS. Instead, it may be a causative factor for this condition. Thus, figuring out the mechanisms of androgen synthesis, conversion, and metabolism is relatively important. Traditionally, studies of androgen excess have largely focused on classical androgen, but in recent years, adrenal-derived 11-oxygenated androgen has also garnered interest. Herein, this Review aims to investigate the origins of androgen excess, androgen synthesis, how androgen receptor (AR) signaling mediates adverse PCOS traits, and the role of 11-oxygenated androgen in the pathophysiology of PCOS. In addition, it provides therapeutic strategies targeting hyperandrogenism in PCOS.

Investigation of androgen receptor CAG repeats length in polycystic ovary syndrome diagnosed using the new international evidence-based guideline

BACKGROUND

To study whether CAG repeat polymorphism of androgen receptor (AR) contributes to the risk of polycystic ovarian morphology (PCOM) with antral follicle count (AFC) ≥ 20 in the context of new international guideline of polycystic ovary syndrome (PCOS).

METHODS

Blood of 109 PCOS cases and 61 controls were collected for the measurement of AR CAG repeats length by sequencing. The mean number and frequency distribution of CAG repeats length were observed. Detailed analysis was conducted by dividing PCOS cases into low AFC group (L-AFC, AFC < 20) and high AFC group (H-AFC, AFC ≥ 20) according to the new international evidence-based guideline.

RESULTS

The portion of individuals with lower CAG repeats length in H-AFC group was significantly larger than those with higher CAG repeats length. Logistic model revealed individuals with lower CAG length tended to develop H-AFC.

CONCLUSION

Lower CAG repeats length in the AR gene of PCOS cases increases risk of PCOM.

Androgen signalling in the ovaries and endometrium

Currently, our understanding of hormonal regulation within the female reproductive system is largely based on our knowledge of estrogen and progesterone signalling. However, while the important functions of androgens in male physiology are well known, it is also recognized that androgens play critical roles in the female reproductive system. Further, androgen signalling is altered in a variety of gynaecological conditions, including endometriosis and polycystic ovary syndrome, indicative of regulatory roles in endometrial and ovarian function. Co-regulatory mechanisms exist between different androgens, estrogens, and progesterone, resulting in a complex network of steroid hormone interactions. Evidence from animal knockout studies, in vitro experiments, and human data indicate that androgen receptor expression is cell-specific and menstrual cycle stage-dependent, with important regulatory roles in the menstrual cycle, endometrial biology, and follicular development in the ovaries. This review will discuss the expression and co-regulatory interactions of androgen receptors, highlighting the complexity of the androgen signalling pathway in the endometrium and ovaries, and the synthesis of androgens from additional alternative pathways previously disregarded as male-specific. Moreover, it will illustrate the challenges faced when studying androgens in female biology, and the need for a more in-depth, integrative view of androgen metabolism and signalling in the female reproductive system.

A review on human reproductive systems encountering with the severe acute respiratory syndrome coronavirus 2 infection

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) is the leading cause of the new deadly pneumonia named coronavirus disease 2019 (COVID-19) pandemic. This pathogen has different co-receptors on various tissues, resulting in vast pathophysiological circumstances. Here, we present a comprehensive narrative review focusing on the impact of SARS-CoV2 on human reproduction. Evidence-based literature revealed inconsistent results for this virus in the reproductive organs of patients with COVID-19, even in the critical phase. Conversely, numerous satisfactory data represented those different reproductive activities, from gametogenesis to pregnancy, can be targeted by SARS-CoV2. The severity of COVID-19 depends on the differential expression of the host cellular components required to enter SARS-CoV2. The cytokine storm and oxidative stress coming out during COVID-19 are associated with complications in reproductive endocrinopathies. Men are naturally more susceptible to COVID-19, especially accompanied by orchitis and varicocele. Synergistically the interaction of SARS-CoV2 and female reproductive failures (polycystic ovary syndrome and endometriosis) increases the susceptibility to COVID-19. Thus, pharmaceutical interventions that ameliorate the complications in individuals with reproductive disorders can be helpful to achieve good outcomes in assisted reproductive techniques. Soon, an increase in the infertility rate will likely be an overall impact of SARS-CoV2 in patients who recovered from COVID-19.

Androgen signaling in adipose tissue, but less likely skeletal muscle, mediates development of metabolic traits in a PCOS mouse model

Polycystic ovary syndrome (PCOS) is a common, multifactorial disorder characterized by endocrine, reproductive, and metabolic dysfunction. As the etiology of PCOS is unknown, there is no cure and symptom-oriented treatments are suboptimal. Hyperandrogenism is a key diagnostic trait, and evidence suggests that androgen receptor (AR)-mediated actions are critical to PCOS pathogenesis. However, the key AR target sites involved remain to be fully defined. Adipocyte and muscle dysfunction are proposed as important sites involved in the manifestation of PCOS traits. We investigated the role of AR signaling in white adipose tissue (WAT), brown adipose tissue (BAT), and skeletal muscle in the development of PCOS in a hyperandrogenic PCOS mouse model. As expected, dihydrotestosterone (DHT) exposure induced key reproductive and metabolic PCOS traits in wild-type (WT) females. Transplantation of AR-insensitive (AR^-/-) WAT or BAT from AR knockout females (ARKO) into DHT-treated WT mice ameliorated some metabolic PCOS features, including increased body weight, adiposity, and adipocyte hypertrophy, but not reproductive PCOS traits. In contrast, DHT-treated ARKO female mice transplanted with AR-responsive (AR^+/+) WAT or BAT continued to resist developing PCOS traits. DHT-treated skeletal muscle-specific AR knockout females (SkMARKO) displayed a comparable phenotype with that of DHT-treated WT females, with full development of PCOS traits. Taken together, these findings infer that both WAT and BAT, but less likely skeletal muscle, are key sites of AR-mediated actions involved in the experimental pathogenesis of metabolic PCOS traits. These data further support targeting adipocyte AR-driven pathways in future research aimed at developing novel therapeutic interventions for PCOS.NEW & NOTEWORTHY Hyperandrogenism is a key feature in the pathogenesis of polycystic ovary syndrome (PCOS); however, the tissue sites of androgen receptor (AR) signaling are unclear. In this study, AR signaling in white and brown adipose tissue, but less likely in skeletal muscle, was found to be involved in the development of metabolic PCOS traits, highlighting the importance of androgen actions in adipose tissue and obesity in the manifestation of metabolic disturbances.

Comparison of Reproductive Function Between Normal and Hyperandrogenemia Conditions in Female Mice With Deletion of Hepatic Androgen Receptor

Obesity, altered glucose homeostasis, hyperinsulinism, and reproductive dysfunction develops in female humans and mammals with hyperandrogenism. We previously reported that low dose dihydrotestosterone (DHT) administration results in metabolic and reproductive dysfunction in the absence of obesity in female mice, and conditional knock-out of the androgen receptor (Ar) in the liver (LivARKO) protects female mice from DHT-induced glucose intolerance and hyperinsulinemia. Since altered metabolic function will regulate reproduction, and liver plays a pivotal role in the reversible regulation of reproductive function, we sought to determine the reproductive phenotype of LivARKO mice under normal and hyperandrogenemic conditions. Using Cre/Lox technology, we deleted the Ar in the liver, and we observed LivARKO female mice have normal puberty timing, cyclicity and reproductive function. After DHT treatment, like control mice, LivARKO experience altered estrous cycling, reduced numbers of corpus lutea, and infertility. Liver Ar is not involved in hyperandrogenemia-induced reproductive dysfunction. The reproductive dysfunction in the DHT-treated LivARKO lean females with normal glucose homeostasis indicates that androgen-induced reproductive dysfunction is independent from metabolic dysfunction.

A Review of Special Considerations on Insulin Resistance Induced Hyperandrogenemia in Women with Polycystic Ovary Syndrome: A Prominent COVID-19 Risk Factor

Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) infecting mechanism depends on hosting angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) as essential components and androgens as regulators for inducing the expression of these components. Therefore, hyperandrogenism-related disease such as polycystic ovary syndrome (PCOS) in insulin resistant women in reproductive-age is a high-risk factor for SARS-CoV-2 infection. Here, we describe the signaling pathways that might increase the susceptibility and severity of this new pandemic in PCOS women with insulin resistance (IR). Luteinizing hormone and insulin increase the risk of SARS-CoV-2 infection in these patients via the induction of steroidogenic enzymes expression through cAMP-response element binding protein and Forkhead box protein O1 (FOXO1), respectively. TMPRSS2 expression is activated through phosphorylation of FOXO1 in ovaries. In other words, SARS-CoV-2 infection is associated with temporary IR by affecting ACE2 and disturbing β-pancreatic function. Therefore, PCOS, IR, and SARS-CoV-2 infection are three corners of the triangle that have complicated relations, and their association might increase the risk of SARS-CoV-2 infection and severity.

Mogroside V Improves Follicular Development and Ovulation in Young-Adult PCOS Rats Induced by Letrozole and High-Fat Diet Through Promoting Glycolysis

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. In this study, we induced a young-adult PCOS rat model by oral administration of letrozole combined with a high-fat diet and then treated with mogroside V (MV) to evaluate the protective effects of MV on endocrine and follicle development in young-adult PCOS rats. MV (600 mg/kg/day) administration not only significantly reduced the body weight and ovary weight, but also attenuated the disrupted estrous cycle and decreased the level of testosterone. MV restored the follicular development, especially by increasing the number of corpus luteum and the thickness of the granular layer in young-adult POCS rats. Moreover, metabolomics showed that MV markedly increased the levels of D-Glucose 6-phosphate, lactate and GTP, while decreased the level of pyruvate. Bioinformatic analysis revealed that MV recovered multiple metabolism-related processes including gluconeogenesis, glycolysis and glucose metabolic process. Further real-time quantitative PCR analysis showed that MV upregulated the expression of lactate dehydrogenase A (Ldha), hexokinase 2 (Hk2) and pyruvate kinase M2 (Pkm2). Western blotting and immunohistochemistry analysis showed that MV restored the expression of lactate dehydrogenase A (Ldha), hexokinase 2 (Hk2) and pyruvate kinase M2 (Pkm2). Collectively, these findings indicated that MV could effectively improve the ovarian microenvironment by upregulating the expression of LDHA, HK2 and PKM2 in granulosa cells and enhancing lactate and energy production, which may contribute to follicle development and ovulation of young-adult PCOS rats.

Reproductive Deficits Induced by Prenatal Antimüllerian Hormone Exposure Require Androgen Receptor in Kisspeptin Cells

Polycystic ovary syndrome (PCOS) is a common reproductive disorder characterized by elevated androgens and antimüllerian hormone (AMH). These hormones remain elevated throughout pregnancy, and potential effects of hormone exposure on offspring from women with PCOS remain largely unexplored. Expanding on recent reports of prenatal AMH exposure in mice, we have fully characterized the reproductive consequences of prenatal AMH (pAMH) exposure throughout the lifespan of first- and second-generation offspring of both sexes. We also sought to elucidate mechanisms underlying pAMH-induced reproductive effects. There is a known reciprocal relationship between AMH and androgens, and in PCOS and PCOS-like animal models, androgen feedback is dysregulated at the level of the hypothalamus. Kisspeptin neurons express androgen receptors and play a critical role in sexual development and function. We therefore hypothesized that pAMH-induced reproductive phenotypes would be mediated by androgen signaling at the level of kisspeptin cells. We tested the pAMH model in kisspeptin-specific androgen receptor knockout (KARKO) mice and found that virtually all pAMH-induced phenotypes assayed are eliminated in KARKO offspring compared to littermate controls. By demonstrating the necessity of androgen receptor in kisspeptin cells to induce pAMH phenotypes, we have advanced understanding of the interactions between AMH and androgens in the context of prenatal exposure, which could have significant implications for children of women with PCOS.

Mesenchymal Stem Cell-Conditioned Media Regulate Steroidogenesis and Inhibit Androgen Secretion in a PCOS Cell Model via BMP-2

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women. Previous studies have demonstrated the therapeutic efficacy of human bone marrow mesenchymal stem cells (BM-hMSCs) for PCOS; however, the regulatory mechanism remains unknown. Bone morphogenetic proteins (BMPs) secreted by BM-hMSCs may underlie the therapeutic effect of these cells on PCOS, based on the ability of BMPs to modulate androgen production and alter steroidogenesis pathway enzymes. In this study, we analyze the effect of BMP-2 on androgen production and steroidogenic pathway enzymes in H295R cells as a human PCOS in vitro cell model. In H295R cells, BMP-2 significantly suppressed cell proliferation, androgen production, and expression of androgen-synthesizing genes, as well as inflammatory gene expression. Furthermore, H295R cells treated with the BM-hMSCs secretome in the presence of neutralizing BMP-2 antibody or with BMP-2 gene knockdown showed augmented expression of androgen-producing genes. Taken together, these results indicate that BMP-2 is a key player mediating the favorable effects of the BM-hMSCs secretome in a human PCOS cell model. BMP-2 overexpression could increase the efficacy of BM-hMSC-based therapy, serving as a novel stem cell therapy for patients with intractable PCOS.

Androgen-induced epigenetic modulations in the ovary

In recent years, androgens have emerged as critical regulators of female reproduction and women's health in general. While high levels of androgens in women are associated with polycystic ovary syndrome (PCOS), recent evidence suggests that a certain amount of direct androgen action through androgen receptor is also essential for normal ovarian function. Moreover, prenatal androgen exposure has been reported to cause developmental reprogramming of the fetus that manifests into adult pathologies, supporting the Developmental Origins of Health and Disease (DOHaD) hypothesis. Therefore, it has become imperative to understand the underlying mechanism of androgen actions and its downstream effects under normal and pathophysiological conditions. Over the years, there has been a lot of studies on androgen receptor function as a transcriptional regulator in the nucleus as well as androgen-induced rapid extra-nuclear signaling. Conversely, new evidence suggests that androgen actions may also be mediated through epigenetic modulation involving both the nuclear and extra-nuclear androgen signaling. This review focuses on androgen-induced epigenetic modifications in female reproduction, specifically in the ovary, and discusses emerging concepts, latest perceptions, and highlight the areas that need further investigation.

Androgens regulate ovarian gene expression by balancing Ezh2-Jmjd3 mediated H3K27me3 dynamics

Conventionally viewed as male hormone, androgens play a critical role in female fertility. Although androgen receptors (AR) are transcription factors, to date very few direct transcriptional targets of ARs have been identified in the ovary. Using mouse models, this study provides three critical insights about androgen-induced gene regulation in the ovary and its impact on female fertility. First, RNA-sequencing reveals a number of genes and biological processes that were previously not known to be directly regulated by androgens in the ovary. Second, androgens can also influence gene expression by decreasing the tri-methyl mark on lysine 27 of histone3 (H3K27me3), a gene silencing epigenetic mark. ChIP-seq analyses highlight that androgen-induced modulation of H3K27me3 mark within gene bodies, promoters or distal enhancers have a much broader impact on ovarian function than the direct genomic effects of androgens. Third, androgen-induced decrease of H3K27me3 is mediated through (a) inhibiting the expression and activity of Enhancer of Zeste Homologue 2 (EZH2), a histone methyltransferase that promotes tri-methylation of K27 and (b) by inducing the expression of a histone demethylase called Jumonji domain containing protein-3 (JMJD3/KDM6B), responsible for removing the H3K27me3 mark. Androgens through the PI3K/Akt pathway, in a transcription-independent fashion, increase hypoxia-inducible factor 1 alpha (HIF1α) protein levels, which in turn induce JMJD3 expression. Furthermore, proof of concept studies involving in vivo knockdown of Ar in the ovary and ovarian (granulosa) cell-specific Ar knockout mouse model show that ARs regulate the expression of key ovarian genes through modulation of H3K27me3.

A mouse model to investigate the impact of testosterone therapy on reproduction in transgender men

STUDY QUESTION

Can mice serve as a translational model to investigate the reproductive effects of testosterone (T) therapy commonly used by transgender men?

SUMMARY ANSWER

T enanthate subcutaneous injections at 0.45 mg twice weekly can be used in the postpubertal C57BL/6N female mouse to investigate the reproductive effects of T therapy given to transgender men.

WHAT IS KNOWN ALREADY

Most models of T treatment in female mice involve prenatal or prepubertal administration, which are not applicable to transgender men who often begin T therapy after puberty. Studies that have looked at the impact of postpubertal T treatment in female mice have generally not investigated reproductive outcomes.

STUDY DESIGN, SIZE, DURATION

A total of 20 C57BL/6N female mice were used for this study. Study groups (n = 5 mice per group) included sesame oil vehicle controls and three doses of T enanthate (0.225, 0.45 and 0.90 mg). Mice were injected subcutaneously twice weekly for 6 weeks.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Daily vaginal cytology was performed prior to initiation of treatment to confirm that all mice were cycling. At 8-9 weeks of age, therapy with subcutaneous T enanthate (0.225, 0.45 or 0.90 mg) or the vehicle control was begun. T therapy continued for 6 weeks, at which point mice were sacrificed and compared to control mice sacrificed during diestrus/metestrus. Data collected included daily vaginal cytology, weekly and terminal reproductive hormone levels, terminal body/organ weights/measurements, ovarian follicular distribution/morphology and corpora lutea counts.

MAIN RESULTS AND THE ROLE OF CHANCE

Of the mice treated with 0.90 mg T enanthate, two of five mice experienced vaginal prolapse, so this group was excluded from further analysis. T enanthate administration twice weekly at 0.225 or 0.45 mg resulted in cessation of cyclicity and persistent diestrus. One of five mice at the 0.225-mg dose resumed cycling after 2.5 weeks of T therapy. As compared to controls, T-treated mice had sustained elevated T levels and luteinizing hormone (LH) suppression in the terminal blood sample. T-treated mice demonstrated increases in clitoral area and atretic cyst-like late antral follicles (0.45 mg only) as compared to controls. No reduction in primordial, primary, secondary or total antral follicle counts was detected in T-treated mice as compared to controls, and T-treated mice demonstrated an absence of corpora lutea.

LIMITATIONS, REASONS FOR CAUTION

Mouse models can provide us with relevant key findings for further exploration but may not perfectly mirror human reproductive physiology.

WIDER IMPLICATIONS OF THE FINDINGS

To our knowledge, this report describes the first mouse model mimicking T therapy given to transgender men that facilitates analysis of reproductive changes. This model allows for future studies comparing duration and reversibility of T-induced changes, on the reproductive and other systems. It supports a role for T therapy in suppressing the hypothalamic-pituitary-gonadal axis in adult female mice as evidenced by LH suppression, persistent diestrus and absence of corpora lutea. The increase in atretic cyst-like late antral follicles aligns with the increased prevalence of polycystic ovary morphology seen in case series of transgender men treated with T therapy. The results also suggest that T therapy does not deplete the ovarian reserve.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the American Society for Reproductive Medicine/Society of Reproductive Endocrinology and Infertility Grant and NIH R01-HD098233 to M.B.M. and University of Michigan Office of Research funding (U058227). H.M.K. was supported by the Career Training in Reproductive Biology and Medical Scientist Training Program T32 NIH Training Grants (T32-HD079342, T32-GM07863) as well as the Cellular and Molecular Biology Program. The University of Virginia Center for Research in Reproduction Ligand Assay and Analysis Core is supported by the Eunice Kennedy Shriver NICHD/NIH (NCTRI) Grant P50-HD28934. E.E.M. consults for Allergan. No other authors have competing interests.

The ovarian stroma as a new frontier

Historically, research in ovarian biology has focused on folliculogenesis, but recently the ovarian stroma has become an exciting new frontier for research, holding critical keys to understanding complex ovarian dynamics. Ovarian follicles, which are the functional units of the ovary, comprise the ovarian parenchyma, while the ovarian stroma thus refers to the inverse or the components of the ovary that are not ovarian follicles. The ovarian stroma includes more general components such as immune cells, blood vessels, nerves, and lymphatic vessels, as well as ovary-specific components including ovarian surface epithelium, tunica albuginea, intraovarian rete ovarii, hilar cells, stem cells, and a majority of incompletely characterized stromal cells including the fibroblast-like, spindle-shaped, and interstitial cells. The stroma also includes ovarian extracellular matrix components. This review combines foundational and emerging scholarship regarding the structures and roles of the different components of the ovarian stroma in normal physiology. This is followed by a discussion of key areas for further research regarding the ovarian stroma, including elucidating theca cell origins, understanding stromal cell hormone production and responsiveness, investigating pathological conditions such as polycystic ovary syndrome (PCOS), developing artificial ovary technology, and using technological advances to further delineate the multiple stromal cell types.

WOMEN IN REPRODUCTIVE SCIENCE: Discovering science and the ovary: a career of joy

My career has been about discovering science and learning the joys of the discovery process itself. It has been a challenging but rewarding process filled with many exciting moments and wonderful colleagues and students. Although I went to college to become a French major, I ultimately stumbled into research while pursuing a Masters Degree in teaching. Thus, my research career began in graduate school where I was studying NAD kinase in the ovary as a possible regulator of steroidogenesis, a big issue in the late 1960s. After a short excursion of teaching in North Dakota, I became a postdoctoral fellow at the University of Michigan, where radio-immuno assays and radio receptor assays had just come on the scene and were transforming endocrinology from laborious bioassays to quantitative science and of course these assays related to the ovary. From there I went to Baylor College of Medicine, a mecca of molecular biology, cloning genes and generating mouse models. It has been a fascinating and joyous journey.

Developmental Programming: Sheep Granulosa and Theca Cell-Specific Transcriptional Regulation by Prenatal Testosterone

Prenatal testosterone (T)-treated sheep, similar to polycystic ovarian syndrome women, manifest reduced cyclicity, functional hyperandrogenism, and polycystic ovary (PCO) morphology. The PCO morphology results from increased follicular recruitment and persistence of antral follicles, a consequence of reduced follicular growth and atresia, and is driven by cell-specific gene expression changes that are poorly understood. Therefore, using RNA sequencing, cell-specific transcriptional changes were assessed in laser capture microdissection isolated antral follicular granulosa and theca cells from age 21 months control and prenatal T-treated (100 mg intramuscular twice weekly from gestational day 30 to 90; term: 147 days) sheep. In controls, 3494 genes were differentially expressed between cell types with cell signaling, proliferation, extracellular matrix, immune, and tissue development genes enriched in theca; and mitochondrial, chromosomal, RNA, fatty acid, and cell cycle process genes enriched in granulosa cells. Prenatal T treatment 1) increased gene expression of transforming growth factor β receptor 1 and exosome component 9, and decreased BCL6 corepressor like 1, BCL9 like, and MAPK interacting serine/threonine kinase 2 in both cells, 2) induced differential expression of 92 genes that included increased mitochondrial, ribosome biogenesis, ribonucleoprotein, and ubiquitin, and decreased cell development and extracellular matrix-related pathways in granulosa cells, and 3) induced differential expression of 56 genes that included increased noncoding RNA processing, ribosome biogenesis, and mitochondrial matrix, and decreased transcription factor pathways in theca cells. These data indicate that follicular function is affected by genes involved in transforming growth factor signaling, extracellular matrix, mitochondria, epigenetics, and apoptosis both in a common as well as a cell-specific manner and suggest possible mechanistic pathways for prenatal T treatment-induced PCO morphology in sheep.

Animal Models to Understand the Etiology and Pathophysiology of Polycystic Ovary Syndrome

More than 1 out of 10 women worldwide are diagnosed with polycystic ovary syndrome (PCOS), the leading cause of female reproductive and metabolic dysfunction. Despite its high prevalence, PCOS and its accompanying morbidities are likely underdiagnosed, averaging > 2 years and 3 physicians before women are diagnosed. Although it has been intensively researched, the underlying cause(s) of PCOS have yet to be defined. In order to understand PCOS pathophysiology, its developmental origins, and how to predict and prevent PCOS onset, there is an urgent need for safe and effective markers and treatments. In this review, we detail which animal models are more suitable for contributing to our understanding of the etiology and pathophysiology of PCOS. We summarize and highlight advantages and limitations of hormonal or genetic manipulation of animal models, as well as of naturally occurring PCOS-like females.

Role of Androgen Receptor for Reconsidering the "True" Polycystic Ovarian Morphology in PCOS

Purpose: Polycystic ovarian morphology (PCOM) is one of the key features of polycystic ovary syndrome (PCOS). The diagnosis of PCOM according to the Rotterdam criteria (≥12 antral follicles per ovary) is debated because of the high prevalence of PCOM in the general population. Androgen receptor (AR) is associated with the PCOS phenotype and might as well play a role during folliculogenesis. This study is aimed to investigate the expression of the AR in PCOS granulosa cells (GCs) and its relationship with the PCOM phenotype. Methods: 106 PCOS cases and 63 controls were included from the Center for Reproductive Medicine, Shandong University. The diagnosis of PCOS was following the Rotterdam criteria (2003). Total RNA was extracted from GCs retrieved from ovarian stimulation. The expression of AR was amplified by means of quantitative real-time polymerase chain reaction. Results: The AR expression was significantly decreased in PCOS cases, especially in the tPCOM subgroup (≥20 antral follicles per ovary). Correlation analyses showed that AR expression was significantly correlated with serum FSH levels in controls and non-tPCOM. In the tPCOM subgroup, the AR expression was significantly correlated with serum LH levels. Interestingly, the significance of these correlations gradually disappeared as the threshold of antral follicles increased above 24 for PCOM. Conclusions:AR was differently expressed in PCOS and especially in the tPCOM subtype. The correlation of AR expression with serum FSH and LH might be associated with the number of follicles in PCOM.

Genes regulating hormone stimulus and response to protein signaling revealed differential expression pattern during porcine oocyte in vitro maturation, confirmed by lipid concentration

Genes influencing oocyte maturation may be valuable for predicting their developmental potential, as well as discerning the mechanistic pathways regulating oocyte development. In the presented research microarray gene expression analysis of immature and in vitro matured porcine oocytes was performed. Two groups of oocytes were compared in the study: before (3 × n = 50) and after in vitro maturation (3 × n = 50). The selection of viable oocytes was performed using the brilliant cresyl blue (BCB) test. Furthermore, microarrays and RT-qPCR was used to analyze the transcriptome of the oocytes before and after IVM. The study focused on the genes undergoing differential expression in two gene-ontology groups: “Cellular response to hormone stimulus” and “Cellular response to unfolded protein”, which contain genes that may directly or indirectly be involved in signal transduction during oocyte maturation. Examination of all the genes of interest showed a lower level of their expression after IVM. From the total number of genes in these gene ontologies ten of the highest change in expression were identified: FOS, ID2, BTG2, CYR61, ESR1, AR, TACR3, CCND2, EGR2 and TGFBR3. The successful maturation of the oocytes was additionally confirmed with the use of lipid droplet assay. The genes were briefly described and related to the literature sources, to investigate their potential roles in the process of oocyte maturation. The results of the study may serve as a basic molecular reference for further research aimed at improving the methods of oocyte in vitro maturation, which plays an important role in the procedures of assisted reproduction.

Impact of Exogenous Testosterone on Reproduction in Transgender Men

Studies show that a subset of transgender men desire children; however, there is a paucity of literature on the effect of gender-affirming testosterone therapy on reproductive function. In this manuscript, we will review the process of gender-affirming hormone therapy for transgender men and what is known about ovarian and uterine consequences of testosterone exposure in transgender men; draw parallels with existing animal models of androgen exposure; summarize the existing literature on parenting experiences and desires in transgender people; discuss considerations for assisted reproductive technologies and fertility preservation; and identify gaps in the literature and opportunities for further research.

The Mechanism of Androgen Actions in PCOS Etiology

Polycystic ovary syndrome (PCOS) is the most common endocrine condition in reproductive-age women. By comprising reproductive, endocrine, metabolic and psychological features—the cause of PCOS is still unknown. Consequently, there is no cure, and management is persistently suboptimal as it depends on the ad hoc management of symptoms only. Recently it has been revealed that androgens have an important role in regulating female fertility. Androgen actions are facilitated via the androgen receptor (AR) and transgenic Ar knockout mouse models have established that AR-mediated androgen actions have a part in regulating female fertility and ovarian function. Considerable evidence from human and animal studies currently reinforces the hypothesis that androgens in excess, working via the AR, play a key role in the origins of polycystic ovary syndrome (PCOS). Identifying and confirming the locations of AR-mediated actions and the molecular mechanisms involved in the development of PCOS is critical to provide the knowledge required for the future development of innovative, mechanism-based interventions for the treatment of PCOS. This review summarises fundamental scientific discoveries that have improved our knowledge of androgen actions in PCOS etiology and how this may form the future development of effective methods to reduce symptoms in patients with PCOS.

Gonadotrope androgen receptor mediates pituitary responsiveness to hormones and androgen-induced subfertility

Many women with hyperandrogenemia suffer from irregular menses and infertility. However, it is unknown whether androgens directly affect reproduction. Since animal models of hyperandrogenemia-induced infertility are associated with obesity, which may impact reproductive function, we have created a lean mouse model of elevated androgen using implantation of low dose dihydrotestosterone (DHT) pellets to separate the effects of elevated androgen from obesity. The hypothalamic-pituitary-gonadal axis controls reproduction. While we have demonstrated that androgen impairs ovarian function, androgen could also disrupt neuroendocrine function at the level of brain and/or pituitary to cause infertility. To understand how elevated androgens might act on pituitary gonadotropes to influence reproductive function, female mice with disruption of the androgen receptor (Ar) gene specifically in pituitary gonadotropes (PitARKO) were produced. DHT treated control mice with intact pituitary Ar (Con-DHT) exhibit disrupted estrous cyclicity and fertility with reduced pituitary responsiveness to GnRH at the level of both calcium signaling and LH secretion. These effects were ameliorated in DHT treated PitARKO mice. Calcium signaling controls GnRH regulation of LH vesicle exotocysis. Our data implicated upregulation of GEM (a voltage-dependent calcium channel inhibitor) in the pituitary as a potential mechanism for androgen's pathological effects. These results demonstrate that gonadotrope AR, as an extra-ovarian regulator, plays an important role in reproductive pathophysiology.

VCAM1 Is Induced in Ovarian Theca and Stromal Cells in a Mouse Model of Androgen Excess

Ovarian theca androgen production is regulated by the pituitary LH and intrafollicular factors. Enhanced androgen biosynthesis by theca cells contributes to polycystic ovary syndrome (PCOS) in women, but the ovarian consequences of elevated androgens are not completely understood. Our study documents the molecular events that are altered in the theca and stromal cells of mice exposed to high androgen levels, using the nonaromatizable androgen DHT. Changes in ovarian morphology and function were observed not only in follicles, but also in the stromal compartment. Genome-wide microarray analyses revealed marked changes in the ovarian transcriptome of DHT-treated females within 1 week. Particularly striking was the increased expression of vascular cell adhesion molecule 1 (Vcam1) specifically in the NR2F2/COUPTF-II lineage theca cells, not granulosa cells, of growing follicles and throughout the stroma of the androgen-treated mice. This response was mediated by androgen receptors (ARs) present in theca and stromal cells. Human theca-derived cultures expressed both ARs and NR2F2 that were nuclear. VCAM1 mRNA and protein were higher in PCOS-derived theca cells compared with control theca and reduced markedly by the AR antagonist flutamide. In the DHT-treated mice, VCAM1 was transiently induced by equine chorionic gonadotropin, when androgen and estrogen biosynthesis peak in preovulatory follicles, and was potently suppressed by a superovulatory dose of human chorionic gonadotropin. High levels of VCAM1 in the theca and interstitial cells of DHT-treated mice and in adult Leydig cells indicate that there may be novel functions for VCAM1 in reproductive tissues, including the gonads.

Impact of estrogens in males and androgens in females

Androgens and estrogens are known to be critical regulators of mammalian physiology and development. While these two classes of steroids share similar structures (in general, estrogens are derived from androgens via the enzyme aromatase), they subserve markedly different functions via their specific receptors. In the past, estrogens such as estradiol were thought to be most important in the regulation of female biology, while androgens such as testosterone and dihydrotestosterone were believed to primarily modulate development and physiology in males. However, the emergence of patients with deficiencies in androgen or estrogen hormone synthesis or actions, as well as the development of animal models that specifically target androgen- or estrogen-mediated signaling pathways, have revealed that estrogens and androgens regulate critical biological and pathological processes in both males and females. In fact, the concept of "male" and "female" hormones is an oversimplification of a complex developmental and biological network of steroid actions that directly impacts many organs. In this Review, we will discuss important roles of estrogens in males and androgens in females.

Physiological and Pathological Androgen Actions in the Ovary

Androgens, although traditionally thought to be male sex steroids, play important roles in female reproduction, both in healthy and pathological states. This mini-review focuses on recent advances in our knowledge of the role of androgens in the ovary. Androgen receptor (AR) is expressed in oocytes, granulosa cells, and theca cells, and is temporally regulated during follicular development. Mouse knockout studies have shown that AR expression in granulosa cells is critical for normal follicular development and subsequent ovulation. In addition, androgens are involved in regulating dynamic changes in ovarian steroidogenesis that are critical for normal cycling. Androgen effects on follicle development have been incorporated into clinical practice in women with diminished ovarian reserve, albeit with limited success in available literature. At the other extreme, androgen excess leads to disordered follicle development and anovulatory infertility known as polycystic ovary syndrome (PCOS), with studies suggesting that theca cell AR may mediate many of these negative effects. Finally, both prenatal and postnatal animal models of androgen excess have been developed and are being used to study the pathophysiology of PCOS both within the ovary and with regard to overall metabolic health. Taken together, current scientific consensus is that a careful balance of androgen activity in the ovary is necessary for reproductive health in women.

Dysregulation of hypothalamic-pituitary estrogen receptor α-mediated signaling causes episodic LH secretion and cystic ovary

Polycystic ovary syndrome (PCOS) is a hypothalamic-pituitary-gonadal (HPG) axis disorder. PCOS symptoms most likely result from a disturbance in the complex feedback regulation system of the HPG axis, which involves gonadotrophic hormones and ovarian steroid hormones. However, the nature of this complex and interconnecting feedback regulation makes it difficult to dissect the molecular mechanisms responsible for PCOS phenotypes. Global estrogen receptor α (ERα) knockout (KO) mice exhibit a disruption of the HPG axis, resulting in hormonal dysregulation in which female ERα KO mice have elevated levels of serum estradiol (E2), testosterone, and LH. The ERα KO females are anovulatory and develop cystic hemorrhagic ovaries that are thought to be due to persistently high circulating levels of LH from the pituitary. However, the role of ERα in the pituitary is still controversial because of the varied phenotypes reported in pituitary-specific ERα KO mouse models. Therefore, we developed a mouse model where ERα is reintroduced to be exclusively expressed in the pituitary on the background of a global ERα-null (PitERtgKO) mouse. Serum E2 and LH levels were normalized in PitERtgKO females and were comparable to wild-type serum levels. However, the ovaries of PitERtgKO adult mice displayed a more overt cystic and hemorrhagic phenotype when compared with ERα KO littermates. We determined that anomalous sporadic LH secretion caused the severe ovarian phenotype of PitERtgKO females. Our observations suggest that pituitary ERα is involved in the estrogen negative feedback regulation, whereas hypothalamic ERα is necessary for the precise control of LH secretion. Uncontrolled, irregular LH secretion may be the root cause of the cystic ovarian phenotype with similarities to PCOS.-Arao, Y., Hamilton, K. J., Wu, S.-P., Tsai, M.-J., DeMayo, F. J., Korach, K. S. Dysregulation of hypothalamic-pituitary estrogen receptor α-mediated signaling causes episodic LH secretion and cystic ovary.

A Hyperandrogenic Mouse Model to Study Polycystic Ovary Syndrome

Hyperandrogenemia plays a critical role in reproductive and metabolic function in females and is the hallmark of polycystic ovary syndrome. Developing a lean PCOS-like mouse model that mimics women with PCOS is clinically meaningful. In this protocol, we describe such a model. By inserting a 4 mm length of DHT (dihydrotestosterone) crystal powder pellet (total length of pellet is 8 mm), and replacing it monthly, we are able to produce a PCOS-like mouse model with serum DHT levels 2 fold higher than mice not implanted with DHT (no-DHT). We observed reproductive and metabolic dysfunction without changing body weight and body composition. While exhibiting a high degree of infertility, a small subset of these PCOS-like female mice can get pregnant and their offspring show delayed puberty and increased testosterone as adults. This PCOS-like lean mouse model is a useful tool to study the pathophysiology of PCOS and the offspring from these PCOS-like dams.

Insulin signaling displayed a differential tissue-specific response to low-dose dihydrotestosterone in female mice

Hyperandrogenemia and hyperinsulinemia are believed to play prominent roles in polycystic ovarian syndrome (PCOS). We explored the effects of low-dose dihydrotestosterone (DHT), a model of PCOS, on insulin signaling in metabolic and reproductive tissues in a female mouse model. Insulin resistance in the energy storage tissues is associated with type 2 diabetes. Insulin signaling in the ovaries and pituitary either directly or indirectly stimulates androgen production. Energy storage and reproductive tissues were isolated and molecular assays were performed. Livers and white adipose tissue (WAT) from DHT mice displayed lower mRNA and protein expression of insulin signaling intermediates. However, ovaries and pituitaries of DHT mice exhibited higher expression levels of insulin signaling genes/proteins. Insulin-stimulated p-AKT levels were blunted in the livers and WAT of the DHT mice but increased or remained the same in the ovaries and pituitaries compared with controls. Glucose uptake decreased in liver and WAT but was unchanged in pituitary and ovary of DHT mice. Plasma membrane GLUTs were decreased in liver and WAT but increased in ovary and pituitary of DHT mice. Skeletal muscle insulin-signaling genes were not lowered in DHT mice compared with control. DHT mice did not display skeletal muscle insulin resistance. Insulin-stimulated glucose transport increased in skeletal muscles of DHT mice compared with controls. DHT mice were hyperinsulinemic. However, the differential mRNA and protein expression pattern was independent of hyperinsulinemia in cultured hepatocytes and pituitary cells. These findings demonstrate a differential effect of DHT on the insulin-signaling pathway in energy storage vs. reproductive tissues independent of hyperinsulinemia.

Antiandrogen Treatment Ameliorates Reproductive and Metabolic Phenotypes in the Letrozole-Induced Mouse Model of PCOS

Polycystic ovary syndrome (PCOS), the most common endocrinopathy in women of reproductive age, is characterized by hyperandrogenism, anovulation, and polycystic ovaries. Although its etiology is unknown, excess androgens are thought to be a critical factor driving the pathology of PCOS. We previously demonstrated that continuous exposure to the aromatase inhibitor letrozole (LET) in mice produces many hallmarks of PCOS, including elevated testosterone (T) and luteinizing hormone, anovulation, and obesity. In the current study, we sought to determine whether androgen receptor (AR) actions are responsible for any of the phenotypes observed in LET mice. C57BL/6 female mice were subcutaneously implanted with LET or placebo control and subsequently treated with the nonsteroidal AR antagonist flutamide or vehicle control. Flutamide treatment in LET females reversed elevated T levels and restored ovarian expression of Cyp17a1 (critical for androgen synthesis) to normal levels. Pituitary expression of Lhb was decreased in LET females that received flutamide treatment, with no changes in expression of Fshb or Gnrhr. Flutamide treatment also restored estrous cycling and reduced the number of ovarian cyst-like follicles in LET females. Furthermore, body weight and adipocyte size were decreased in flutamide-treated LET females. Altogether, our findings provide strong evidence that AR signaling is responsible for many key reproductive and metabolic PCOS phenotypes and further establish the LET mouse model as an important tool for the study of androgen excess.

Ovarian Follicular Theca Cell Recruitment, Differentiation, and Impact on Fertility: 2017 Update

The major goal of this review is to summarize recent exciting findings that have been published within the past 10 years that, to our knowledge, have not been presented in detail in previous reviews and that may impact altered follicular development in polycystic ovarian syndrome (PCOS) and premature ovarian failure in women. Specifically, we will cover the following: (1) mouse models that have led to discovery of the derivation of two precursor populations of theca cells in the embryonic gonad; (2) the key roles of the oocyte-derived factor growth differentiation factor 9 on the hedgehog (HH) signaling pathway and theca cell functions; and (3) the impact of the HH pathway on both the specification of theca endocrine cells and theca fibroblast and smooth muscle cells in developing follicles. We will also discuss the following: (1) other signaling pathways that impact the differentiation of theca cells, not only luteinizing hormone but also insulinlike 3, bone morphogenic proteins, the circadian clock genes, androgens, and estrogens; and (2) theca-associated vascular, immune, and fibroblast cells, as well as the cytokines and matrix factors that play key roles in follicle growth. Lastly, we will integrate what is known about theca cells from mouse models, human-derived theca cell lines from patients who have PCOS and patients who do not have PCOS, and microarray analyses of human and bovine theca to understand what pathways and factors contribute to follicle growth as well as to the abnormal function of theca.

Female Offspring From Chronic Hyperandrogenemic Dams Exhibit Delayed Puberty and Impaired Ovarian Reserve

Female offspring of many species exposed to high doses of androgens in utero experience endocrine dysfunction during adulthood. The phenotype of offspring from females with prepregnancy hyperandrogenemia and impaired ovulation, however, has not been examined. We developed a mouse model of hyperandrogenemia by implanting a low-dose dihydrotestosterone (DHT) pellet 15 days before conception. Female offspring born to dams with hyperandrogenemia (DHT daughters) had delayed puberty (P < 0.05) with first estrus on postnatal day (PND) 41 compared with daughters from dams with physiological levels of DHT (non-DHT daughters, PND37.5). Serum follicle-stimulating hormone (FSH) levels in the DHT daughters were fourfold higher (P < 0.05) on PND21, and anti-Müllerian hormone levels were higher (P < 0.05) on PND26 than in non-DHT daughters (controls). DHT daughters showed an extended time in metestrus/diestrus and a shorter time in the proestrus/estrus phase compared with non-DHT daughters (P < 0.05). To examine ovarian response to gonadotropins, superovulation was induced and in vitro fertilization (IVF) was performed. Fewer numbers of oocytes were retrieved from the DHT daughters compared with non-DHT daughters (P < 0.05). At IVF, there was no difference in rates of fertilization or cleavage of oocytes from either group. There were fewer (P < 0.01) primordial follicles (6.5 ± 0.8 vs 14.5 ± 2.1 per ovary) in the ovaries of DHT daughters compared with non-DHT daughters. Daughters from hyperandrogenemic females exhibited elevated prepubertal FSH levels, diminished ovarian response to superovulation, impaired estrous cyclicity, delayed onset of puberty, and reduced ovarian reserve, suggesting that fetal androgen exposure had lasting effects on female reproductive function.

"Positive Regulation of RNA Metabolic Process" Ontology Group Highly Regulated in Porcine Oocytes Matured In Vitro: A Microarray Approach

The cumulus-oocyte complexes (COCs) growth and development during folliculogenesis and oogenesis are accompanied by changes involving synthesis and accumulation of large amount of RNA and proteins. In this study, the transcriptomic profile of genes involved in “oocytes RNA synthesis” in relation to in vitro maturation in pigs was investigated for the first time. The RNA was isolated from oocytes before and after in vitro maturation (IVM). Interactions between differentially expressed genes/proteins belonging to “positive regulation of RNA metabolic process” ontology group were investigated by STRING10 software. Using microarray assays, we found expression of 12258 porcine transcripts. Genes with fold change higher than |2| and with corrected p value lower than 0.05 were considered as differentially expressed. The ontology group “positive regulation of RNA metabolic process” involved differential expression of AR, INHBA, WWTR1, FOS, MEF2C, VEGFA, IKZF2, IHH, RORA, MAP3K1, NFAT5, SMARCA1, EGR1, EGR2, MITF, SMAD4, APP, and NR5A1 transcripts. Since all of the presented genes were downregulated after IVM, we suggested that they might be significantly involved in regulation of RNA synthesis before reaching oocyte MII stage. Higher expression of “RNA metabolic process” related genes before IVM indicated that they might be recognized as important markers and specific “transcriptomic fingerprint” of RNA template accumulation and storage for further porcine embryos growth and development.

The Role of Central Androgen Receptor Actions in Regulating the Hypothalamic-Pituitary-Ovarian Axis

The androgen receptor (AR) is expressed throughout the hypothalamic-pituitary-gonadal (HPG) axis, and findings from female global AR knockout mice confirm that AR-mediated androgen actions play important roles in regulating female reproductive function. We generated neuron-specific AR knockout mice (NeurARKO) to investigate the functional role of neuronal AR-mediated androgen action in regulating the female HPG axis and fertility. Relative to control females, NeurARKO females exhibited elevated luteinizing hormone (LH) levels at diestrus (p < 0.05) and a compromised serum LH response to ovariectomy and E2 priming (p < 0.01). Furthermore, NeurARKO females displayed reduced Kiss1 mRNA expression in the anteroventral periventricular nucleus at diestrus (p < 0.05) and proestrus (p < 0.05), but elevated Kiss1 (p < 0.05) and neurokinin B (Tac2, p < 0.05) mRNA expression in the arcuate nucleus at proestrus compared to WT controls. Ovarian follicle dynamics were also altered in NeurARKO ovaries at 3 months of age, with a significant reduction in large antral follicle numbers at the proestrus stage compared to control WT ovaries (p < 0.05). Increased follicular atresia was evident in NeurARKO ovaries with a 4-fold increase in unhealthy large preantral follicles (p < 0.01). Despite the findings of aberrant neuroendocrine and ovarian characteristics in the NeurARKO females, estrous cyclicity and overall fertility were comparable between NeurARKO and WT females. In conclusion, our findings revealed that selective loss of neuronal AR actions impacts the kisspeptin/GnRH/LH cascade leading to compromised ovarian follicle dynamics.