Expression of miR-15a, miR-145, and miR-182 in granulosa-lutein cells, follicular fluid, and serum of women with polycystic ovary syndrome (PCOS)

miRNA expression in PCOS: unveiling a paradigm shift toward biomarker discovery

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder that affects a substantial percentage of women, estimated at around 9-21%. This condition can lead to anovulatory infertility in women of childbearing age and is often accompanied by various metabolic disturbances, including hyperandrogenism, insulin resistance, obesity, type-2 diabetes, and elevated cholesterol levels. The development of PCOS is influenced by a combination of epigenetic alterations, genetic mutations, and changes in the expression of non-coding RNAs, particularly microRNAs (miRNAs). MicroRNAs, commonly referred to as non-coding RNAs, are approximately 22 nucleotides in length and primarily function in post-transcriptional gene regulation, facilitating mRNA degradation and repressing translation. Their dynamic expression in different cells and tissues contributes to the regulation of various biological and cellular pathways. As a result, they have become pivotal biomarkers for various diseases, including PCOS, demonstrating intricate associations with diverse health conditions. The aberrant expression of miRNAs has been detected in the serum of women with PCOS, with overexpression and dysregulation of these miRNAs playing a central role in the atypical expression of endocrine hormones linked to PCOS. This review takes a comprehensive approach to explore the upregulation and downregulation of various miRNAs present in ovarian follicular cells, granulosa cells, and theca cells of women diagnosed with PCOS. Furthermore, it discusses the potential for a theragnostic approach using miRNAs to better understand and manage PCOS.

A glance into the roles of microRNAs (exosomal and non-exosomal) in polycystic ovary syndrome

Polycystic ovarian syndrome (PCOS) is a common endocrine disorder in women of reproductive age. The clinical symptoms include hyperandrogenism, chronic anovulation, and multiple ovarian cysts. PCOS is strongly associated with obesity and insulin resistance. MicroRNAs (miRNAs) are a group of short non-coding RNAs that play a role in the post-transcriptional regulation of gene expression and translational inhibition. They play a vital role in the regulation of multiple metabolic and hormonal processes as well as in oocyte maturation and folliculogenesis in the female reproductive system. miRNAs can be used as diagnostic biomarkers or therapeutic targets because of their stability. The encapsulation of miRNAs in extracellular vesicles or exosomes contributes to their stability. Exosomes are constantly secreted by many cells and size of about 30 to 150 nm. Enveloping miRNAs exosomes can release them for cellular communication. The induced transfer of miRNAs by exosomes is a novel process of genetic exchange between cells. Many studies have shown that along with non-exosomal miRNAs, different types of exosomal miRNAs derived from the serum and follicular fluid can play an essential role in PCOS pathogenesis. These miRNAs are involved in follicular development and various functions in granulosa cells, apoptosis, cell proliferation, and follicular atresia. The present study aimed to comprehensively review the evidence on miRNAs and their affected pathways under both non-exosomal and exosomal circumstances, primarily focusing on the pathogenesis of PCOS.

Current Advances in Cellular Approaches for Pathophysiology and Treatment of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a prevalent gynecological and endocrine disorder that results in irregular menstruation, incomplete follicular development, disrupted ovulation, and reduced fertility rates among affected women of reproductive age. While these symptoms can be managed through appropriate medication and lifestyle interventions, both etiology and treatment options remain limited. Here we provide a comprehensive overview of the latest advancements in cellular approaches utilized for investigating the pathophysiology of PCOS through in vitro cell models, to avoid the confounding systemic effects such as in vitro fertilization (IVF) therapy. The primary objective is to enhance the understanding of abnormalities in PCOS-associated folliculogenesis, particularly focusing on the aberrant roles of granulosa cells and other relevant cell types. Furthermore, this article encompasses analyses of the mechanisms and signaling pathways, microRNA expression and target genes altered in PCOS, and explores the pharmacological approaches considered as potential treatments. By summarizing the aforementioned key findings, this article not only allows us to appreciate the value of using in vitro cell models, but also provides guidance for selecting suitable research models to facilitate the identification of potential treatments and understand the pathophysiology of PCOS at the cellular level.

Multi-omics insights and therapeutic implications in polycystic ovary syndrome: a review

Polycystic ovary syndrome (PCOS) is a common gynecological disease that causes adverse effects in women in their reproductive phase. Nonetheless, the molecular mechanisms remain unclear. Over the last decade, sequencing and omics approaches have advanced at an increased pace. Omics initiatives have come to the forefront of biomedical research by presenting the significance of biological functions and processes. Thus, multi-omics profiling has yielded important insights into understanding the biology of PCOS by identifying potential biomarkers and therapeutic targets. Multi-omics platforms provide high-throughput data to leverage the molecular mechanisms and pathways involving genetic alteration, epigenetic regulation, transcriptional regulation, protein interaction, and metabolic alterations in PCOS. The purpose of this review is to outline the prospects of multi-omics technologies in PCOS research by revealing novel biomarkers and therapeutic targets. Finally, we address the knowledge gaps and emerging treatment strategies for the management of PCOS. Future PCOS research in multi-omics at the single-cell level may enhance diagnostic and treatment options.

Evaluation of the potential of miR-21 as a diagnostic marker for oocyte maturity and embryo quality in women undergoing ICSI

MicroRNAs are small molecules that play a crucial role in regulating a woman's reproductive system. The present study evaluates the expression of miR-21 in the serum, follicular fluid (FF), and cumulus cells (CCs) and their association with oocyte maturity and embryo quality in women undergoing intracytoplasmic sperm injection. Women subjects were divided into the case (54 Patients with female factor infertility) and control groups (33 patients with male factor infertility). The level of miR-21 was measured using Real-Time PCR. The level of miR-21 was significantly lower in the CCs, FF, and serum in the case compared to the control group (p < 0.05). MiR-21 abundance was higher in FF and CCs samples than in serum. Furthermore, there was a significant increase in CCs to FF in the case group (p < 0.05). A significant decrease in oocyte count, MII oocytes, and percentage of mature oocytes were observed in the case group (p < 0.05). The expression of miR-21 in FF and CCs was positively related to oocyte maturation, but no correlation with embryo development was observed. This study found that miR-21 is expressed less in women with female factor infertility, and human oocytes' development is crucially affected by the expression of miR-21. Therefore, miR-21 could provide new helpful biomarkers of oocyte maturity.

Multiomics Analysis-Based Biomarkers in Diagnosis of Polycystic Ovary Syndrome

Polycystic ovarian syndrome is an utmost communal endocrine, psychological, reproductive, and metabolic disorder that occurs in women of reproductive age with extensive range of clinical manifestations. This may even lead to long-term multiple morbidities including obesity, diabetes mellitus, insulin resistance, cardiovascular disease, infertility, cerebrovascular diseases, and ovarian and endometrial cancer. Women affliction from PCOS in midst assemblage of manifestations allied with menstrual dysfunction and androgen exorbitance, which considerably affects eminence of life. PCOS is recognized as a multifactorial disorder and systemic syndrome in first-degree family members; therefore, the etiology of PCOS syndrome has not been copiously interpreted. The disorder of PCOS comprehends numerous allied health conditions and has influenced various metabolic processes. Due to multifaceted pathophysiology engaging several pathways and proteins, single genetic diagnostic tests cannot be supportive to determine in straight way. Clarification of cellular and biochemical pathways and various genetic players underlying PCOS could upsurge our consideration of pathophysiology of this syndrome. It is requisite to know pathophysiological relationship between biomarker and their reflection towards PCOS disease. Biomarkers deliver vibrantly and potent ways to apprehend the spectrum of PCOS with applications in screening, diagnosis, characterization, and monitoring. This paper relies on the endeavor to point out many candidates as potential biomarkers based on omics technologies, thus highlighting correlation between PCOS disease with innovative technologies. Therefore, the objective of existing review is to encapsulate more findings towards cutting-edge advances in prospective use of biomarkers for PCOS disease. Discussed biomarkers may be fruitful in guiding therapies, addressing disease risk, and predicting clinical outcomes in future.

The Translational Role of miRNA in Polycystic Ovary Syndrome: From Bench to Bedside—A Systematic Literature Review

MicroRNAs (miRNAs) are small, non-coding RNAs that are essential for the regulation of post-transcriptional gene expression during tissue development and differentiation. They are involved in the regulation of manifold metabolic and hormonal processes and, within the female reproductive tract, in oocyte maturation and folliculogenesis. Altered miRNA levels have been observed in oncological and inflammatory diseases, diabetes or polycystic ovary syndrome (PCOS). Therefore, miRNAs are proving to be promising potential biomarkers. In women with PCOS, circulating miRNAs can be obtained from whole blood, serum, plasma, urine, and follicular fluid. Our systematic review summarizes data from 2010–2021 on miRNA expression in granulosa and theca cells; the relationship between miRNAs, hormonal changes, glucose and lipid metabolism in women with PCOS; and the potential role of altered miRNAs in fertility (oocyte quality) in PCOS. Furthermore, we discuss miRNAs as a potential therapeutic target in PCOS and as a diagnostic marker for PCOS.

Metabolomics combined with network pharmacology to explore the mechanisms of modified Guishen pill to ameliorate polycystic ovary syndrome

BACKGROUND

The modified Guishen pill (MGP) has a prominent therapeutic effect on polycystic ovary syndrome (PCOS). However, its mechanism is still unclear. This study aimed to uncover the mechanism of MGP for PCOS treatment through a comprehensive strategy integrating metabolomics and network pharmacology.

METHODS

A letrozole-induced PCOS model was used to evaluate ovarian function in rats. Plasma metabolomics was used to authenticate differential metabolites and enriched related pathways using the MetaboAnalyst platform. Network pharmacology was utilized to explore the endogenous targets of MGP treatment for PCOS. Finally, the potential targets and related biological functions were verified experimentally.

RESULTS

MGP improved PCOS symptoms by regulating abnormal levels of sex hormones and alleviating ovarian pathological changes in rats; fifty-four potential differential metabolites involved in MGP treatment for PCOS, and the hub genes derived from network pharmacology were consistent with the metabolomic analysis results to varying degrees. The comprehensive analysis identified that a key novel target for endothelial nitric oxide synthase (eNOS/NOS3), five key metabolites (ornithine, citrulline, l-glutamic acid, acetylornithine, and hydroxyproline), and one pathway (arginine and proline metabolism) were related to the therapy of PCOS with MGP. Subsequently, we verified the localization and expression of eNOS in the ovaries, and it significantly improved insulin resistance, apoptosis, and oxidative stress in letrozole-induced PCOS rats.

CONCLUSION

Our work reveals the complex mechanism of MGP therapy for PCOS. This study is a successful paradigm for elucidating the pharmacological mechanism of the traditional Chinese medicine compound.

Circ_0043532 regulates miR-182/SGK3 axis to promote granulosa cell progression in polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disease in women at childbearing age. Several circular RNAs (circRNAs) have been demonstrated to be involved in PCOS. In this study, we aimed to explore the function and mechanism of circ_0043532 in PCOS.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to determine the expression of circ_0043532, miR-182 and serum/glucocorticoid regulated kinase family member 3 (SGK3). Cell proliferation was assessed by 5-ethynyl-2'-deoxyuridine (EdU) assay and 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Flow cytometry analysis was employed to evaluate cell cycle and cell apoptosis. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were conducted to verify the association between miR-182 and SGK3. Western blot assay was carried out to determine the protein level of SGK3.

RESULTS

Circ_0043532 was markedly elevated in PCOS granulosa cells (GCs) and KGN cells. Silencing of circ_0043532 suppressed cell proliferation and cell cycle process and promoted cell apoptosis in PCOS GCs and KGN cells. For mechanistic analysis, circ_0043532 was identified as a sponge of miR-182 and SGK3 was confirmed to be a target gene of miR-182. Inhibition of miR-182 rescued the impacts of circ_0043532 interference on PCOS GCs and KGN cell progression. Moreover, miR-182 overexpression suppressed cell proliferation and cell cycle process and promoted cell apoptosis in PCOS GCs and KGN cells by targeting SGK3.

CONCLUSION

Deficiency of circ_0043532 suppressed cell proliferation and induced cell cycle arrest and cell apoptosis in PCOS by modulation of miR-182/SGK3 axis.

microRNAs in female infertility: An overview

Infertility impacts a considerable number of women worldwide, and it affects different aspects of family life and society. Although female infertility is known as a multifactorial disorder, there are strong genetic and epigenetic bases. Studies revealed that miRNAs play critical roles in initiation and development of female infertility related disorders. Early diagnosis and control of these diseases is an essential key for improving disease prognosis and reducing the possibility of infertility and other side effects. Investigating the possible use of miRNAs as biomarkers and therapeutic options is valuable, and it merits attention. Thus, in this article, we reviewed research associated with female diseases and highlighted microRNAs that are related to the polycystic ovary syndrome (up to 30 miRNAs), premature ovarian failure (10 miRNAs), endometriosis (up to 15 miRNAs), uterine fibroids (up to 15 miRNAs), endometrial polyp (3 miRNAs), and pelvic inflammatory (6 miRNAs), which are involved in one or more ovarian or uterine disease-causing processes.

Epigenetic inheritance of polycystic ovary syndrome - challenges and opportunities for treatment

Polycystic ovary syndrome (PCOS) is the main cause of female infertility worldwide and is associated with a substantially increased lifetime risk of comorbidities, including type 2 diabetes mellitus, psychiatric disorders and gynaecological cancers. Despite its high prevalence (~15%) and substantial economic burden, the aetiology of PCOS remains elusive. The genetic loci linked to PCOS so far account for only ~10% of its heritability, which is estimated at 70%. However, growing evidence suggests that altered epigenetic and developmental programming resulting from hormonal dysregulation of the maternal uterine environment contributes to the pathogenesis of PCOS. Male as well as female relatives of women with PCOS are also at an increased risk of developing PCOS-associated reproductive and metabolic disorders. Although PCOS phenotypes are highly heterogenous, hyperandrogenism is thought to be the principal driver of this condition. Current treatments for PCOS are suboptimal as they can only alleviate some of the symptoms; preventative and targeted treatments are sorely needed. This Review presents an overview of the current understanding of the aetiology of PCOS and focuses on the developmental origin and epigenetic inheritance of this syndrome.

miR-130b regulates gap junctional intercellular communication through connexin 43 in granulosa cells from patients with polycystic ovary syndrome

MicroRNAs (miRNAs) are small, noncoding RNAs that negatively regulate gene expression post-transcriptionally. We explored whether connexin 43 (Cx43) was differently expressed in luteinized granulosa cells from women with polycystic ovary syndrome (PCOS) compared with luteinized granulosa cells from women with a normal menstrual cycle, and whether certain miRNAs regulate the Cx43 level and gap junctional intercellular communication (GJIC). The miRNA profile was investigated in ovarian cortex tissues from five women with PCOS and five women without PCOS using a miRNA microarray. The levels of miR-130b and Cx43 mRNA were measured using real-time PCR in human luteinized granulosa cells from 20 women with PCOS and 25 women without PCOS. Protein and mRNA expression analysis and luciferase assays were conducted to confirm the substrate of miR-130b. PCOS ovarian cortex showed differential expression of miRNAs compared with non-PCOS ovarian cortex. Furthermore, miR-130b levels were increased in PCOS ovarian cortex and in luteinized granulosa cells compared with those in women with normal menstrual cycles, whereas the level of Cx43 mRNA, the identified target of miR-130b, was decreased in granulosa cells from patients with PCOS. Overexpression of miR-130b in a granulosa cell line resulted in reduced Cx43 protein levels and inhibited GJIC using scrape loading and dye transfer assay. Meanwhile, inhibition of miR-130b increased the Cx43 level. In conclusion, miR-130b was increased in PCOS granulosa cells, where it targets Cx43 to affect GJIC. The results of the present study suggested that miR-130b, via post-transcriptional regulation of Cx43, is involved in the pathophysiology of PCOS, which provides new insight into the pathological mechanism of PCOS.

Multiomics Analysis Reveals Molecular Abnormalities in Granulosa Cells of Women With Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most common complex endocrine and metabolic disease in women of reproductive age. It is characterized by anovulatory infertility, hormone disorders, and polycystic ovarian morphology. Regarding the importance of granulosa cells (GCs) in the pathogenesis of PCOS, few studies have investigated the etiology at a single “omics” level, such as with an mRNA expression array or methylation profiling assay, but this can provide only limited insights into the biological mechanisms. Here, genome-wide DNA methylation together with lncRNA-miRNA-mRNA profiles were simultaneously detected in GCs of PCOS cases and controls. A total of 3579 lncRNAs, 49 miRNAs, 669 mRNAs, and 890 differentially methylated regions (DMR)-associated genes were differentially expressed between PCOS cases and controls. Pathway analysis indicated that these differentially expressed genes were commonly associated with steroid biosynthesis and metabolism-related signaling, such as glycolysis/gluconeogenesis. In addition, we constructed ceRNA networks and identified some known ceRNA axes, such as lncRNAs-miR-628-5p-CYP11A1/HSD17B7. We also identified many new ceRNA axes, such as lncRNAs-miR-483-5p-GOT2. Interestingly, most ceRNA axes were also closely related to steroid biosynthesis and metabolic pathways. These findings suggest that it is important to systematically consider the role of reproductive and metabolic genes in the pathogenesis of PCOS.

Urinary Cell-Free miR-99a-5p as a Potential Biomarker for Estrus Detection in Buffalo

Accurate estrus detection method is the need of the hour to improve reproductive efficiency of buffaloes in dairy industry, as the currently available estrus detection methods/tools lack high sensitivity and specificity. Recently, circulating miRNAs have been shown as non-invasive biomarkers by various studies. Hence, in order to evaluate their potential as estrus biomarkers, the objective of this study was to identify and compare the levels of 10 hormone-responsive miRNAs in the urine collected at proestrus (PE), estrus (E), and diestrus (DE) phases of buffaloes (n = 3) pertaining to a discovery sample. Among 10 urinary miRNAs, the levels of bta-mir-99a-5p (E/PE 0.5-fold, P < 0.05; DE/PE 1.9-fold), bta-miR-125b (E/PE 0.5-fold; DE/PE 0.7-fold), bta-mir-145 (E/PE 1.5-fold; DE/PE 0.7-fold), bta-mir-210 (E/PE 1.2-fold, DE/PE 0.7-fold), mir-21 (E/PE 1.5-fold, DE/PE 2-fold), and bta-mir-191 (E/PE 1.3-fold; DE/PE 0.8-fold) were found to be altered during different phases of buffalo estrous cycle. In contrast, bta-mir-126-3p, bta-let-7f, bta-mir-16b, and bta-mir-378 were undetected in buffalo urine. Furthermore, a validation study in an independent group of 25 buffalo heifers showed the increased levels of urinary bta-mir-99a-5p during the DE (3.92-fold; P < 0.0001) phase as compared to the E phase. Receiver operating characteristic curve analyses also revealed the ability of urinary miR-99a-5p in distinguishing the E from the DE phase (area under the curve of 0.6464; P < 0.08). In silico analysis further showed an enrichment of miR-99a-5p putative targets in various ovarian signaling pathways, including androgen/estrogen/progesterone biosynthesis and apoptosis signaling, implicating the role of miR-99a-5p in ovarian physiology. In conclusion, significantly lower levels of bta-mir-99a-5p at the E phase than the DE phase in buffalo urine indicate its biomarker potential, which needs to be further explored in a large cohort in the future studies.

The Potential Relationship Between Different Human Female Reproductive Disorders and Sperm Quality in Female Genital Tract

Spermatozoa should travel throughout the female reproductive tract to reach its ultimate goal, fertilization of the oocyte. At the ejaculation moment, millions of sperm within a few milliliters of the ejaculate are deposited at the cranial segment of vagina and make their journey to the fertilization site. This is done by means of various factors, such as sperm motility, the uterine and fallopian tubes contractility, and the ciliary movement of the lining cells. During this migration, spermatozoa interact with the female microenvironment both physically and molecularly. In this regard, the quality of the environmental conditions may affect this interaction. Therefore, some alterations in women's genital tract microenvironment, such as conditions that occur in female reproductive disorders, may have detrimental effects on sperm reproductive function. In this review, human sperm migration through the female tract is described, and the potential effects of different reproductive disorders at reproductive organs, such as vagina, uterine cervix, uterus, fallopian tubes, and ovary on sperm survival and quality, are also argued. The understanding of those conditions that may impair sperm fertility in the female genital tract can provide a more accurate diagnosis of the causes of infertility in couples. This can ultimately lead to the discovery of effective treatment approaches.

An Insight on the Role of Altered Function and Expression of Exosomes and MicroRNAs in Female Reproductive Diseases

Exosomes are small bilayer-lipid membrane vesicles secreted by living cells that are able to transfer regulatory molecules and genetic information from one cell to another. These vesicles are enriched with several nucleic acids including mRNAs, microRNAs (miRNAs), other non-coding RNAs, as well as proteins and lipids. Alterations in the exosomal content and functions are observed in numerous reproductive diseases in both animals and human cases. MicroRNAs, a class of small endogenous RNA molecules, can negatively regulate gene expression at the post-transcription level. Aberrant microRNA expression has been reported in multiple human reproductive diseases such as polycystic ovary syndrome, preeclampsia, uterine leiomyomata, ovarian cancer, endometriosis, and Asherman's syndrome. This study focuses to review recent research on alterations of microRNA expression and the role of exosomes in female reproductive diseases. It has been demonstrated that exosomes may be a potential therapeutic approach in various female reproductive diseases. In addition, changes in expression of microRNAs act as molecular biomarkers for diagnosis of several reproductive diseases in women, and regulation of their expression can potentially reduce infertility.

Aberrant Expression of Long Non-coding RNAs in Exosomes in Follicle Fluid From PCOS Patients

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disease characterized by persistent anovulation and hyperandrogenism, affecting approximately 8–10% of women of childbearing age and occupying an important position in the etiology of infertility. There is increasing evidence that long non-coding RNAs (lncRNAs) are involved in the development of PCOS, but the potential regulatory mechanism is still unclear. This study performed high-throughput lncRNA sequencing of follicular fluid exosomes in non-PCOS infertility patients and PCOS infertility patients. The sequencing results led to the identification of 1,253 upregulated and 613 downregulated lncRNAs from a total of 1,866 detected candidates. There was no significant difference between the PCOS patients and non-PCOS patients in body mass index (BMI) or the fasting blood glucose (FBG) level. However, luteinizing hormone (LH), estradiol (E2), testosterone (T), serum prolactin (PRL), and anti-Mullerian hormone (AMH) levels were clearly upregulated in PCOS patients compared to those in non-PCOS patients. There was also an increase in LH/FSH (>2) in the PCOS patients. Functional analysis showed pathways related to endocytosis, the Hippo, the MAPK, and HTLV-1 infection. These results suggest that lncRNAs may play an important role in the pathogenesis of PCOS and may be potential targets for the diagnosis and treatment of PCOS.

Non-coding RNAs in polycystic ovary syndrome: a systematic review and meta-analysis

BACKGROUND

Genetic, environmental and epigenetical factors may play important roles in the pathogenesis of polycystic ovary syndrome (PCOS), however the etiology of PCOS remains unclear. Studies indicated that non-coding RNAs (ncRNAs) were involved in the occurrence and development of PCOS. Thus, we aim to perform a systematic review and meta-analysis to investigate the presence and dysregulated expression of ncRNAs in human PCOS.

METHODS

We searched in PubMed, Medline, Web of Science and Embase until July 2019 and summarized all eligible publications focusing on microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and small interfering RNAs (siRNAs) in PCOS.

RESULTS

Sixty-seven articles were included in our systematic review and 9 articles were included in meta-analysis. There is little overlap between studies when comparing miRNA profiles. Sensitivity analysis showed that the expression of miR-93 was upregulated in PCOS patients (WMD 0.75, P < 0.00001), without heterogeneity among remaining studies (I2 = 0%).

CONCLUSION

A large number of ncRNAs with altered levels were observed in plasma, serum, follicular fluid, granulosa cells or other issues from PCOS patients. Aberrant ncRNAs expression in PCOS may lead to aberrant steroidogenesis, adipocyte dysfunction, altered ovarian cell proliferation and/or apoptosis and have the potential to be used as diagnostic biomarkers.

The role of miRNAs in polycystic ovary syndrome with insulin resistance

PURPOSE

This review aims to summarize the key findings of several miRNAs and their roles in polycystic ovary syndrome with insulin resistance, characterize the disease pathogenesis, and establish a new theoretical basis for diagnosing, treating, and preventing polycystic ovary syndrome.

METHODS

Relevant scientific literature was covered from 1992 to 2020 by searching the PubMed database with search terms: insulin/insulin resistance, polycystic ovary syndrome, microRNAs, and metabolic diseases. References of relevant studies were cross-checked.

RESULTS

The related miRNAs (including differentially expressed miRNAs) and their roles in pathogenesis, and possible therapeutic targets and pathways, are discussed, highlighting controversies and offering thoughts for future directions.

CONCLUSION

We found abundant evidence on the role of differentially expressed miRNAs with its related phenotypes in PCOS. Considering the essential role of insulin resistance in the pathogenesis of PCOS, the alterations of associated miRNAs need more research attention. We speculate that race/ethnicity or PCOS phenotype and differences in methodological differences might lead to inconsistencies in research findings; thus, several miRNA profiles need to be investigated further to qualify for the potential therapeutic targets for PCOS-IR.

Prediction of major microRNAs in follicular fluid regulating porcine oocyte development

PURPOSE

The aim of the present study was to identify key microRNAs (miRNAs) in porcine follicular fluid (FF) that regulate oocyte growth.

METHODS

miRNAs contained in FF were determined by small RNA-seq of exosome RNA. Upstream regulator miRNA was determined by ingenuity pathway analysis using differentially expressed genes in granulosa cells (GCs) between small follicles (1-2 mm in diameter) and large follicles (3-5 mm), and between follicles containing oocytes of high developmental ability and follicles containing oocytes of low developmental ability. The candidate miRNAs overlapping among the three miRNAs group were determined. Lastly, the effect of supplementation with FF, exosome-depleted FFs, or each miRNA on in vitro oocyte growth was examined.

RESULTS

The miRNAs determined were miR-17, -27, -92a, and -145. These miRNAs were found in the spent culture medium of oocytes and granulosa cells complexes and serum by small RNA sequencing. Culturing of oocytes and granulosa cells complexes collected from porcine early antral follicles (0.5-0.7 mm in diameter) with FF for 14 days improved oocyte growth; depletion of exosomes from the FFs neutralized the beneficial effect observed. miR-92a mimic increased the antrum formation and diameter, together with acetylated levels of H4K12 in oocytes. In addition, supplementation of miRNA mimics miR-17b, -92a, and -145b improved the rate of chromatin configuration, and miR-17b and -92a mimics improved the developmental ability of oocytes to the blastocyst stage.

CONCLUSION

miR-17, -92a, and -145 are major miRNA candidates in follicular fluids regulating oocyte growth.

Extracellular microRNA profiling in human follicular fluid: new biomarkers in female reproductive potential

MicroRNAs (miRNAs) are small, about 22 nucleotides, non-coding RNAs which regulate a wide range of gene expression during post-transcriptional stage. They are released into intra- and extracellular microenvironments and play vital roles in different physiological and pathological pathways. Due to easy accessibility, detection of extracellular miRNAs in body fluids, e.g. serum, plasma, cerebrospinal fluid, and follicular fluid, has been explored in recent years. Since miRNAs are stable at unsuitable conditions, scientists have been investigating to use them as biomarkers in different fields of medicines. It goes without saying that experienced biomarkers would be required in reproductive medicine as well. Biomarkers can help clinicians and embryologists to diagnose disorders and assess the embryo quality via molecular pattern which is more reliable than nowadays routine methods. Follicular fluid as a noninvasive fluid in assisted reproductive techniques (ART) has attracted researchers as a rich pool for biomarkers, and miRNAs are not exception. Although miRNA biomarkers in reproduction field are located on their initial stage and there is a long path to move forward, several meticulous studies have been performed and discovered their associations with various conditions. In this regard, we summarize the reported miRNAs in follicular fluid and their correlations with female infertility and ART success rate, while subsequent investigations are required.

Dysregulated miR-142, -33b and -423 in granulosa cells target TGFBR1 and SMAD7: a possible role in polycystic ovary syndrome

It is well established that microRNA (miRNA) expression profiles are altered in patients with polycystic ovary syndrome (PCOS). In addition, abnormal transforming growth factor beta (TGFB) signaling in granulosa cells is related to the pathological conditions of PCOS. However, the function of dysregulated miRNAs in PCOS is still unclear. In this study, we aimed to elucidate the roles of specific miRNAs in PCOS. We collected follicular fluid from 46 patients with PCOS and 32 healthy controls. Granulosa cells (GCs) were separated and the levels of six candidate miRNAs were determined by quantitative RT-PCR. The direct targets of three dysregulated miRNAs were predicted using bioinformatic tools and confirmed using a dual luciferase assay and immunoblotting. The biological function of three dysregulated miRNAs in primary GCs was determined using a cell proliferation assay and flow cytometry. We found that miR-423 expression was downregulated (P = 0.038), and the levels of miR-33b (P = 0.032) and miR-142 (P = 0.021) were upregulated in GCs from patients with PCOS, compared to controls. miR-423 directly repressed SMAD family member 7 (SMAD7) expression, while transforming growth factor beta receptor 1 (TGFBR1) was a direct target of both miR-33b and miR-142. An RNA oligonucleotide mixture containing miR-423 inhibitor, miR-33b mimic, and miR-142 mimic repressed TGFB signaling, promoted cell proliferation (P = 0.0098), repressed apoptosis (P = 0.027), and increased S phase cell numbers (P = 0.0036) in primary cultures of GCs, compared to the cells treated with a sequence scrambled control RNA oligonucleotide. This study unveiled the possible roles of three miRNAs in PCOS and might provide candidate biomarkers for PCOS diagnosis while in vivo functional studies, using transgenic or knockout mouse models, are expected to confirm the roles of dysregulated miRNAs in the pathogenesis of PCOS.

Comprehensive analysis of mRNAs and miRNAs in the ovarian follicles of uniparous and multiple goats at estrus phase

Background

Fertility is an important economic trait in the production of meat goat, and follicular development plays an important role in fertility. Although many mRNAs and microRNAs (miRNAs) have been found to play critical roles in ovarian biological processes, the interaction between mRNAs and miRNAs in follicular development is not yet completely understood. In addition, less attention has been given to the study of single follicle (dominant or atretic follicle) in goats. This study aimed to identify mRNAs, miRNAs, and signaling pathways as well as their interaction networks in the ovarian follicles (large follicles and small follicles) of uniparous and multiple Chuanzhong black goats at estrus phase using RNA-sequencing (RNA-seq) technique.

Results

The results showed that there was a significant difference in the number of large follicles between uniparous and multiple goats (P < 0.05), but no difference in the number of small follicles was observed (P > 0.05). For the small follicles of uniparous and multiple goats at estrus phase, 289 differentially expressed mRNAs (DEmRNAs) and 16 DEmiRNAs were identified; and for the large follicles, 195 DEmRNAs and 7 DEmiRNAs were identified. The functional enrichment analysis showed that DE genes in small follicles were significantly enriched in ovarian steroidogenesis and steroid hormone biosynthesis, while in large follicles were significantly enriched in ABC transporters and steroid hormone biosynthesis. The results of quantitative real-time polymerase chain reaction were consistent with those of RNA-seq. Analysis of the mRNA-miRNA interaction network suggested that CD36 (miR-122, miR-200a, miR-141), TNFAIP6 (miR-141, miR-200a, miR-182), CYP11A1 (miR-122), SERPINA5 (miR-1, miR-206, miR-133a-3p, miR-133b), and PTGFR (miR-182, miR-122) might be related to fertility, but requires further research on follicular somatic cells.

Conclusions

This study was used for the first time to reveal the DEmRNAs and DEmiRNAs as well as their interaction in the follicles of uniparous and multiple goats at estrus phase using RNA-seq technology. Our findings provide new clues to uncover the molecular mechanisms and signaling networks of goat reproduction that could be potentially used to increase ovulation rate and kidding rate in goat.

Similar miRNomic signatures characterize the follicular fluids collected after follicular and luteal phase stimulations in the same ovarian cycle

PURPOSE

To detect putative differences in the miRNomic profile of follicular fluids collected after follicular-phase-stimulation (FPS-FFs) and paired luteal-phase-stimulation (LPS-FFs) in the same ovarian cycles (DuoStim).

METHODS

Exploratory study at a private IVF center and University involving FPS-FFs and paired-LPS-FFs collected from 15 reduced ovarian reserve and advanced maternal age women undergoing DuoStim (n = 30 paired samples). The samples were combined in 6 paired pools (5 samples each) and balanced according to maternal age and number of cumulus-oocyte-complexes. Micro-RNAs were isolated and sequenced. Four miRNAs were then selected for further validation on 6 single pairs of FPS-FFs and LPS-FFs by qPCR.

RESULTS

Forty-three miRNAs were detected in both FPS-FFs and paired-LPS-FFs after sequencing and no statistically significant differences were reported. Thirty-three KEGG pathways were identified as regulated from the detected miRNAs. Four miRNAs (miR-146b, miR-191, miR-320a, and miR-483) were selected for qPCR validation since consistently expressed in our samples and possibly involved in the regulation/establishment of a healthy follicular environment. Again, no significant differences were reported between FPS-FFs and paired-LPS-FFs, also when the analysis was corrected for maternal age and number of cumulus-oocyte-complexes in generalized linear models.

CONCLUSIONS

These data complement the embryological, chromosomal, and clinical evidence of equivalence between FPS and LPS published to date.

Hyperandrogenism and Metabolic Syndrome Are Associated With Changes in Serum-Derived microRNAs in Women With Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) remains one of the most common endocrine disorder in premenopausal women with an unfavorable metabolic risk profile. Here, we investigate whether biochemical hyperandrogenism, represented by elevated serum free testosterone, resulted in an aberrant circulating microRNA (miRNAs) expression profile and whether miRNAs can identify those PCOS women with metabolic syndrome (MetS). Accordingly, we measured serum levels of miRNAs as well as biochemical markers related to MetS in a case-control study of 42 PCOS patients and 20 Controls. Patients were diagnosed based on the Rotterdam consensus criteria and stratified based on serum free testosterone levels (≥0.034 nmol/l) into either a normoandrogenic (n = 23) or hyperandrogenic (n = 19) PCOS group. Overall, hyperandrogenic PCOS women were more insulin resistant compared to normoandrogenic PCOS women and had a higher prevalence of MetS. A total of 750 different miRNAs were analyzed using TaqMan Low-Density Arrays. Altered levels of seven miRNAs (miR-485-3p, -1290, -21-3p, -139-3p, -361-5p, -572, and -143-3p) were observed in PCOS patients when compared with healthy Controls. Stratification of PCOS women revealed that 20 miRNAs were differentially expressed between the three groups. Elevated serum free testosterone levels, adjusted for age and BMI, were significantly associated with five miRNAs (miR-1290, -20a-5p, -139-3p, -433-3p, and -361-5p). Using binary logistic regression and receiver operating characteristic curves (ROC), a combination panel of three miRNAs (miR-361-5p, -1225-3p, and -34-3p) could correctly identify all of the MetS cases within the PCOS group. This study is the first to report comprehensive miRNA profiling in different subgroups of PCOS women with respect to MetS and suggests that circulating miRNAs might be useful as diagnostic biomarkers of MetS for a different subset of PCOS.

Altered miR-186 and miR-135a contribute to granulosa cell dysfunction by targeting ESR2: A possible role in polycystic ovary syndrome

MicroRNAs (miRNAs) are a group of negative regulators of gene expression that function at the posttranscriptional level. Dysregulation of miRNAs is involved in many pathophysiological processes, including polycystic ovary syndrome (PCOS). In this study, we first detected the expression levels of 6 candidate miRNA in granulosa cells (GCs) from 63 women with PCOS and 20 healthy controls. We found that miR-186 and miR-135a were overexpressed in GCs from PCOS patients. Subsequently, the direct targets of miR-186 and miR-135a were predicted using bioinformatics analysis and verified by luciferase assays and immunoblotting. The present study determined that miR-186 and miR-135a repressed ESR2 expression in GCs, which further inhibited CDKN1A expression, promoted GC proliferation and repressed GC apoptosis. Meanwhile, the levels of miR-186 and miR-135a in GCs were found to positively correlate with serum estradiol levels in patients with PCOS. Furthermore, estradiol treatment directly increased miR-186 and miR-135a levels in KGN and primary GCs, which provides new insight into understanding the pathophysiology of PCOS.

miRNA Profiling Reveals miRNA-130b-3p Mediates DENND1A Variant 2 Expression and Androgen Biosynthesis

Polycystic ovary syndrome (PCOS) is a common endocrine disorder of reproductive-age women involving overproduction of ovarian androgens and, in some cases, from the adrenal cortex. Family studies have established that PCOS is a complex heritable disorder with genetic and epigenetic components. Several small, noncoding RNAs (miRNAs) have been shown to be differentially expressed in ovarian cells and follicular fluid and in the circulation of women with PCOS. However, there are no reports of global miRNA expression and target gene analyses in ovarian theca cells isolated from normal cycling women and women with PCOS, which are key to the elucidation of the basis for the hyperandrogenemia characteristic of PCOS. With the use of small RNA deep sequencing (miR-seq), we identified 18 differentially expressed miRNAs in PCOS theca cells; of these, miR-130b-3p was predicted to target one of the PCOS genome-wide association study candidates, differentially expressed in neoplastic vs normal cells domain containing 1A (DENND1A). We previously reported that DENND1A variant 2 (DENND1A.V2), a truncated isoform of DENND1A, is upregulated in PCOS theca cells and mediates augmented androgen biosynthesis in PCOS theca cells. The comparison of miR-130b-3p in normal and PCOS theca cells demonstrated decreased miR-130b-3p expression in PCOS theca cells, which was correlated with increased DENND1A.V2, cytochrome P450 17α-hydroxylase (CYP17A1) mRNA and androgen biosynthesis. miR-130b-3p mimic studies established that increased miR130b-3p is correlated with decreased DENND1A.V2 and CYP17A1 expression. Thus, in addition to genetic factors, post-transcriptional regulatory mechanisms via miR-130b-3p underly androgen excess in PCOS. Ingenuity® Pathway Analysis Core Pathway and Network Analyses suggest a network by which miR-130b-3p, DENND1A, the luteinizing hormone/choriogonadotropin receptor, Ras-related protein 5B, and signaling pathways that they potentially target may mediate hyperandrogenism in PCOS.

Extracellular microRNAs profile in human follicular fluid and IVF outcomes

Encapsulated microRNAs (i.e., miRNAs within the extracellular vesicles, i.e., EV-miRNAs) have been detected in follicular fluid in both animal and human studies and different profiles have been associated with IVF cycle characteristics. However, limited studies to date have investigated other IVF outcomes, including fertilization status and embryo quality on day three". In this cohort, we performed a cross-sectional analysis on 126 women who contributed follicular fluid from a single follicle during a single IVF cycle. One hundred and ninety-two EV-miRNAs were assessed by univariable fold-change and multivariable logistic regression analyses. Hsa-miR-92a and hsa-miR-130b, were over-expressed in follicular fluid samples from oocytes that failed to fertilize compared to those that were normally fertilized. Additionally, hsa-miR-888 was over-expressed and hsa-miR-214 and hsa-miR-454 were under-expressed in samples that resulted in impaired day-3 embryo quality compared to top-quality day-3 embryos. After adjusting for confounders as BMI, smoking and total motile sperm, associations of these EV-miRNAs remained significant. In-silico KEGG pathway analyses assigned the identified EV-miRNAs to pathways of follicular growth and development, cellular signaling, oocyte meiosis, and ovarian function. Our findings suggest that EV-miRNAs may play a role in pathways of ovarian function and follicle development, which could be essential for understanding the molecular mechanisms that could lead to a successful pregnancy and birth.

Ovarian and Extra-Ovarian Mediators in the Development of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder affecting women of reproductive age. The origin of PCOS is still not clear and appears to be a function of gene x environment interactions. This review addresses the current knowledge of the genetic and developmental contributions to the etiology of PCOS, the ovarian and extra-ovarian mediators of PCOS and the gaps and key challenges that need to be addressed in the diagnosis, treatment and prevention of PCOS.