Altered microRNA and gene expression in the follicular fluid of women with polycystic ovary syndrome

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.

miRNAs as a novel clinical biomarker and therapeutic targets in polycystic ovary syndrome (PCOS): A review

Polycystic ovary syndrome (PCOS) is the most prevalent endocrine disorder in females of the reproductive age. PCOS is commonly manifested as ovulatory dysfunction, clinical and biochemical excess androgen level, and polycystic ovaries. Metabolic sequelae associated with PCOS, including insulin resistance (IR), type 2 diabetes (T2DM), obesity and increased cardiometabolic risk. The underlying pathology of PCOS is not fully understood with various genetic and environmental factors have been proposed. MicroRNAs (miRNAs), are endogenously produced, small non-coding, single-stranded RNAs that capable of regulating gene expression at the post-transcriptional level. Altered miRNAs expression has been associated with various disorders, including T2DM, IR, lipid disorder, infertility, atherosclerosis, endometriosis, and cancer. Given that PCOS also present with similar features, there is an increasing interest to investigate the role of miRNAs in the diagnosis and management of PCOS. In recent years, studies have demonstrated that miRNAs are present in various body fluids, including follicular fluid of women with PCOS. Therefore, it may act as a potential biomarker and could serve as a novel therapeutic target for the diagnosis and treatment of PCOS. This review aims to summarise the up to date research on the relation between miRNAs and PCOS and explore its potential role in the diagnosis and the management of PCOS.

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.

Exosomes: Emerging biomarkers and targets in folliculogenesis and endometriosis

An appropriate connection of the cells in the ovary follicles is vital for a healthy ovule maturation and fertilization, and also for endometrium preparation for implantation that can cause endometriosis. Cellular communication within the follicle and endometrial epithelium involve many signaling molecules. Recent studies indicate that cellular communication can be enclosed by secretion and absorption of small membrane carriers which are named extracellular vesicles including exosomes and microvesicles. Understanding and defining these EVs (Extracellular vesicles) population are important for future studies and clinical translation. Here, we describe the various important cargos which are carried by exosomes during folliculogenesis and endometriosis. Additionally, the current knowledge of exosomes and their cargo within the FF (Follicular fluid) during the folliculogenesis and also in the intrauterine cavity which are involved in endometriosis lesions have also been summarized. Considering the potential importance of this form of the cell to cell communication in the reproductive system, the vital issues under discussion lead to a new insight in this rapidly expanding field and it may be an interesting approach for diagnostic, prognostic and especially therapeutic strategies in the field of infertility and assisted reproductive technology (ART).

miR-424 suppresses proliferation and promotes apoptosis of human ovarian granulosa cells by targeting Apelin and APJ expression

OBJECTIVE

Polycystic ovary syndrome (PCOS) is associated with alteration of Apelin signaling in ovarian granulosa cells (GCs). However, the molecular mechanisms regulating Apelin expression remain poorly understood. This study aims to investigate the role of miR-424 in modulating Apelin expression and GC functions.

METHODS

miRNA expression in GCs was altered by transfection with specific miR-424 mimics and inhibitors. Apelin level was determined by ELISA. miR-424 and mRNA expression were analyzed by quantitative RT-PCR. Protein abundance was measured by western blotting. Genomic sequence targeted by miR-424 was validated by dual-luciferase reporter assay. Apelin gene was overexpressed by transfection of LV-003 vector carrying its cDNA. GC proliferation was analyzed by MTS method, and its cell cycle progression and apoptosis were measured by flow cytometry.

RESULTS

Apelin concentration was increased in serum and follicular fluid from PCOS patients, accompanied by upregulated APJ (Apelin receptor) expression and suppressed miR-424 expression in GCs. miR-424 mimics suppressed Apelin and APJ expression in KGN cells by targeting 3' UTR of Apelin and APJ, whereas miR-424 inhibitors had the opposite effects. miR-424 inhibited KGN cell proliferation and cell cycle progression by down-regulating Cyclin-D/E expression. Moreover, miR-424 promoted KGN cell apoptosis by increasing truncated Caspase-3 level. The regulation of KGN cell proliferation and apoptosis by miR-424 was mediated by directly suppressing Apelin gene expression, instead of inhibiting Apelin peptide activity.

CONCLUSION

miR-424 suppresses proliferation and promotes apoptosis of human ovarian granulosa cells by directly targeting and inhibiting Apelin and APJ expression.

Pathophysiological roles of chronic low-grade inflammation mediators in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common hormonal imbalance disease in reproductive-aged women. Its basic characteristics are ovulatory dysfunction and ovarian overproduction of androgens that lead to severe symptoms such as insulin resistance, hirsutism, infertility, and acne. Notwithstanding the disease burden, its underlying mechanisms remain unknown, and no causal therapeutic exists. In recent years, further studies showed that inflammation processes are involved in ovulation and play a key role in ovarian follicular dynamics. Visceral adipose tissue can cause inflammatory response and maintenance of the inflammation state in adipocytes by augmented production of inflammatory cytokines, monocyte chemoattractant proteins, and recruitment of the immune cell. Therefore, the PCOS can be related to a low-grade inflammation state and inflammatory markers. Investigating the inflammatory processes and mediators that contribute to the commencement and development of PCOS can be a critical step for better understanding the pathophysiology of the disease and its treatment through inhibition or control of related pathways. In the present review, we discuss the pathophysiological roles of chronic low-grade inflammation mediators including inflammasome-related cytokines, interleukin-1β (IL-1β), and IL-18 in PCOS development.

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.

Ovarian aging increases small extracellular vesicle CD81+ release in human follicular fluid and influences miRNA profiles

Ovarian aging affects female reproductive potential and is characterized by alterations in proteins, mRNAs and non-coding RNAs inside the ovarian follicle. Ovarian somatic cells and the oocyte communicate with each other secreting different molecules into the follicular fluid, by extracellular vesicles. The cargo of follicular fluid vesicles may influence female reproductive ability; accordingly, analysis of extracellular vesicle content could provide information about the quality of the female germ cell.In order to identify the most significant deregulated microRNAs in reproductive aging, we quantified the small extracellular vesicles in human follicular fluid from older and younger women and analyzed the expression of microRNAs enclosed inside the vesicles. We found twice as many small extracellular vesicles in the follicular fluid from older women and several differentially expressed microRNAs. Correlating microRNA expression profiles with vesicle number, we selected 46 deregulated microRNAs associated with aging. Bioinformatic analyses allowed us to identify six miRNAs involved in TP53 signaling pathways. Specifically, miR-16-5p, miR214-3p and miR-449a were downregulated and miR-125b, miR-155-5p and miR-372 were upregulated, influencing vesicle release, oocyte maturation and stress response. We believe that this approach allowed us to identify a battery of microRNAs strictly related to female reproductive aging.

MicroRNAs in combined spent culture media and sperm are associated with embryo quality and pregnancy outcome

OBJECTIVE

To identify differentially abundant miRNAs in sperm samples and spent culture media (SCM) of embryos of different grade toward a prediction of pregnancy outcome.

DESIGN

Array-based reverse-transcription quantitative polymerase chain reaction profiling and validation.

SETTING

University research institute and in vitro fertilization center.

PATIENT(S)

Couples (n = 61) undergoing infertility treatment with the use of intracytoplasmic sperm injection.

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

Abundance levels of miRNAs in combined SCM of embryos of different quality and in sperm samples associated with pregnancy outcome.

RESULT(S)

Out of 372 screened miRNAs, miR-19b-3p and let-7a-5p were detected consistently in all SCM and sperm samples. The abundance levels of miRNAs were significantly altered between SCM of embryos with different quality (G1, G2, and G3 grades). Specifically, miR-320a and miR-15a-5p were differentially abundant in G1 vs. G2, miR-21-5p in G1 vs. G3, and miR-20a-5p in G2 vs. G3. The abundance levels of combined SCM and sperm derived miRNAs were also significantly altered between different pregnancy outcomes. MiR-19b-3p showed the highest area under the receiver operating characteristic curve values between positive and negative outcomes, with lower abundance levels in both combined SCM and sperm samples associated with a positive pregnancy outcome. MiR-320a, miR-15a-5p, miR-21-5p, and miR-20a-5p showed similar results in combined SCM samples.

CONCLUSION(S)

miRNA abundance levels in combined SCM and sperm differed significantly depending on embryo quality and pregnancy outcome. MiR-19b-3p may serve as a potential biomarker to predict pregnancy outcome.

The expression of small RNAs in exosomes of follicular fluid altered in human polycystic ovarian syndrome

Polycystic ovary syndrome (PCOS) can cause reproductive disorders that may affect oocyte quality from punctured follicles in human follicular fluid (HFF). The non-coding RNA family includes micro RNA (miRNA), piwi-interacting RNA (piRNA) and transfer RNA (tRNA); these non-coding RNA transcripts play diverse functions and are implicated in a variety of diseases and health conditions, including infertility. In this study, to explore the role of HFF exosomes in PCOS, we extracted and sequenced RNA from HFF exosomes of PCOS patients and compared the analysis results with those of non-PCOS control group. The HFF exosomes were successfully isolated and characterized in a variety of ways. The sequencing results of the HFF exosomal RNA showed that about 6.6% of valid reads in the PCOS group and 8.6% in the non-PCOS group were successfully mapped to the human RNA database. Using a hierarchical clustering method, we found there were ten small RNA sequences whose expression was significantly different between the PCOS and non-PCOS groups. We chose six of them to predict target genes of interest for further GO analysis, and pathway analysis showed that the target genes are mainly involved in biosynthesis of amino acids, glycine, serine and glycosaminoglycan, as well as threonine metabolism. Therefore, the small RNA sequences contained in HFF EXs may play a key role in the mechanism that drives PCOS pathogenesis, and thereby can act as molecular biomarkers for PCOS diagnosis in the future.

Implications of miRNA expression pattern in bovine oocytes and follicular fluids for developmental competence

Developmental competence determines the oocyte capacity to support initial embryo growth, but the molecular mechanisms underlying this phenomenon are still ill-defined. Changes in microRNA (miRNA) expression pattern have been described during follicular growth in several species. Therefore, aim of this study was to investigate whether miRNA expression pattern in cow oocyte and follicular fluid (FF) is associated with the acquisition of developmental competence. Samples were collected from ovaries with more than, or fewer than, 10 mid-antral follicles (H- and L-ovaries) because previous studies demonstrated that this parameter is a reliable predictor of oocyte competence. After miRNA deep sequencing and bioinformatic data analysis, we identified 58 miRNAs in FF and 6 in the oocyte that were differentially expressed between H- and L-ovaries. Overall, our results indicate that miRNA levels both in FF and in the ooplasm must remain within specific thresholds and that changes in either direction compromising oocyte competence. Some of the miRNAs found in FF (miR-769, miR-1343, miR-450a, miR-204, miR-1271 and miR-451) where already known to regulate follicle growth and their expression pattern indicate that they are also involved in the acquisition of developmental competence. Some miRNAs were differentially expressed in both compartments but with opposite patterns, suggesting that miRNAs do not flow freely between FF and oocyte. Gene Ontology analysis showed that the predicted gene targets of most differentially expressed miRNAs are part of a few signalling pathways. Regulation of maternal mRNA storage and mitochondrial activity seem to be the processes more functionally relevant in determining oocyte quality. In conclusion, our data identified a few miRNAs in the follicular fluid and in the ooplasm that modulate the oocyte developmental competence. This provides new insights that could help with the management of cattle reproductive efficiency.

The role of miRNAs in regulating adrenal and gonadal steroidogenesis

miRNAs are endogenous noncoding single-stranded small RNAs of ~22 nucleotides in length that post-transcriptionally repress the expression of their various target genes. They contribute to the regulation of a variety of physiologic processes including embryonic development, differentiation and proliferation, apoptosis, metabolism, hemostasis and inflammation. In addition, aberrant miRNA expression is implicated in the pathogenesis of numerous diseases including cancer, hepatitis, cardiovascular diseases and metabolic diseases. Steroid hormones regulate virtually every aspect of metabolism, and acute and chronic steroid hormone biosynthesis is primarily regulated by tissue-specific trophic hormones involving transcriptional and translational events. In addition, it is becoming increasingly clear that steroidogenic pathways are also subject to post-transcriptional and post-translational regulations including processes such as phosphorylation/dephosphorylation, protein‒protein interactions and regulation by specific miRNAs, although the latter is in its infancy state. Here, we summarize the recent advances in miRNA-mediated regulation of steroidogenesis with emphasis on adrenal and gonadal steroidogenesis.

The Expression of miRNAs in Human Ovaries, Oocytes, Extracellular Vesicles, and Early Embryos: A Systematic Review

The recent discovery of microRNAs (miRNAs) in human reproductive tissues and cells indicates a possible functional role in reproductive function. However, the studies published to date in female reproductive tissues/cells and embryos are inconclusive and sometimes controversial. In order to update the knowledge of this field, the present study aimed to discuss, through a systematic review, the role of miRNAs in female human reproduction and early embryogenesis. We conducted a systematic review of the published literature in MEDLINE and EMBASE databases through June 2018 (plus a complementary search until July 2019), in accordance with the PRISMA guidelines. We have included descriptive and observational studies, in which fertile/infertile women were well-defined. The primary outcome was the miRNA expression in ovaries, oocytes, extracellular vesicles, and embryos. We identified 25,204 articles, of which 28 were selected for qualitative analysis: 18 in ovaries and extracellular vesicles, three in oocytes, and seven in embryos. The present systematic review of descriptive and observational studies demonstrates that aberrant miRNA expression in female reproductive tissues/cells and embryos is related with infertility and embryogenesis errors. The expression of specific miRNAs, particularly in extracellular vesicles, may be used in the future as biomarkers of infertility and prognostic tools of embryo development.

MicroRNA-30d-5p promotes ovarian granulosa cell apoptosis by targeting Smad2

Polycystic ovarian syndrome (PCOS) is one of the leading causes of female infertility. MicroRNA-30d-5p (miR-30d-5p) has been reported to be significantly increased during follicle stimulating hormone (FSH)-mediated progesterone secretion of cultured granulosa cells. However, its role in the proliferation and apoptosis of ovarian granulosa cells is unclear. The present study aimed to investigate the role of miR-30d-5p in the proliferation and apoptosis of ovarian granulosa cells. Bioinformatic analysis and dual-luciferase reporter assay were used to predict and confirm the direct target of miR-30d-5p. The levels of miR-30d-5p were detected via reverse transcription-quantitative PCR (RT-qPCR), cell proliferation was detected via an MTT assay and cell apoptosis was measured via flow cytometry. The levels of phosphorylated (p)-Smad2, Smad2, p-Smad3 and Smad3 were detected by performing a western blot assay or RT-qPCR. In the present results, Smad2 was identified as the direct and functional target of miR-30d-5p. Compared with the control and control plasmid groups, the Smad2 plasmid significantly enhanced Smad2 mRNA levels in rat ovarian granulosa cells, enhanced rat ovarian granulosa cell viability and reduced cell apoptosis. In addition, the results demonstrated that overexpression of miR-30d-5p significantly decreased the level of Smad2, the effect of which was reversed by the Smad2-plasmid. Furthermore, it was demonstrated that the enhanced expression of miR-30d-5p significantly inhibited ovarian granulosa cell proliferation and promoted cell apoptosis. Restoration of Smad2 reversed the effect of miR-30d-5p on ovarian granulosa cell proliferation and apoptosis. Transfection with miR-30d-5p mimics significantly decreased the expression of Smad2 and increased the relative p-Smad2/Smad2 and p-Smad3/Smad3 levels in ovarian granulosa cells, which was reversed by overexpressing Smad2. The present study demonstrated that the overexpression of miR-30d-5p reduced proliferation and induced the apoptosis of granulosa cells by targeting Smad2. The molecular mechanism of ovarian granulosa cell apoptosis may therefore be explained by the newly identified miR-30d-5p/Smad2 axis, which represents a novel potential treatment target for PCOS.

Expression of microRNA in follicular fluid in women with and without PCOS

Several studies have shown the expression of small non-coding microRNA (miRNA) changes in PCOS and their expression in follicular fluid has been described, though the number of studies remains small. In this prospective cohort study, miRNA were measured using quantitative polymerase chain reaction (qPCR) in 29 weight and aged matched anovulatory women with PCOS and 30 women without from follicular fluid taken at the time of oocyte retrieval who were undergoing in vitro fertilization (IVF); miRNA levels were determined from a miRNA data set. 176 miRNA were detected, of which 29 differed significantly between normal women and PCOS women. Of these, the top 7 (p < 0.015) were miR-381-3p, miR-199b-5p, miR-93-3p, miR-361-3p, miR-127-3p, miR-382-5p, miR-425-3p. In PCOS, miR-382-5p correlated with age and free androgen index (FAI), miR-199b-5p correlated with anti-mullerian hormone (AMH) and miR-93-3p correlated with C-reactive protein (CRP). In normal controls, miR-127-3p, miR-382-5p and miR-425-3p correlated with the fertilisation rate; miR-127-3p correlated with insulin resistance and miR-381-3p correlated with FAI. Ingenuity pathway assessment revealed that 12 of the significantly altered miRNA related to reproductive pathways, 12 miRNA related to the inflammatory disease pathway and 6 were implicated in benign pelvic disease. MiRNAs differed in the follicular fluid between PCOS and normal control women, correlating with age, FAI, inflammation and AMH in PCOS, and with BMI, fertilization rate (3 miRNA), insulin resistance, FAI and inflammation in control women, according to Ingenuity Pathway Analysis.

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.

Expressed proteins and activated pathways in conditioned embryo culture media from IVF patients are diverse according to infertility factors

OBJECTIVE

Given that the embryo culture medium secretome reflects the embryo development, we hypothesize that protein profiles are affected according to infertility factors, which can be responsible for detrimental embryonic developmental competence. The aim of this study was to screen the protein profile of conditioned embryo culture media in patients presenting deep infiltrating endometriosis (ENDO) and polycystic ovarian syndrome (PCOS) undergoing IVF, by proteomics approaches. The control group was constituted by tubal factor patients.

METHODS

Patients underwent in vitro fertilization (IVF) treatment as routine and oocytes were fertilized by ICSI. The embryos were group cultured until day 3 of development, and after transfer the culture media were collected. For the proteomics analysis, two pools of samples were prepared for groups CONTROL and PCOS, and 4 pools of samples for group DIE. Samples were prepared to deplete high abundant proteins and followed evaluated by high throughput proteomics approach.

RESULTS

The embryonic organ and tissue development were physiological functions activated, based on proteins identified in the 3 study groups of samples. The samples coming from DIE patients presented a high calcium activity and on the other hand, embryos coming from PCOS patients showed a decreased calcium action. Other pathways as grow factors through the EGF signaling pathway overexpressed in ENDO culture medium and protein kinase A in PCOS were also observed.

CONCLUSIONS

Proteomic embryonic secretome will advance our knowledge of early embryogenesis and additionally could lead to improved selection of embryos for transfer warrants further investigation.

SRSFs mediate the function of AR in the ovarian granulosa cells of patients with PCOS

Ovarian hyperandrogenism is one of the characteristics of polycystic ovary syndrome (PCOS) and androgen receptor (AR) in ovarian granulosa cells (GCs) functions as an important element to the accumulation of androgens. This study verified the existence of alternative splicing variant of AR (AR-SVs) in the GCs of PCOS patients and found that the function of AR decreased significantly in the presence of AR-SVs. And compared to the normal individuals, the expression of Serine/arginine-rich splicing factor 2(SRSF2) was higher and the expression of SRSF3 was lower in the GCs of patients with AR-SVs. More importantly, we found that the expression of SRSF2 was inhibited and that the expression of AR was decreased after the successful upregulation of miRNA-183, and testostrone (T) concentrations in the culture medium were increased. The results also showed that the expression of SRSF3 decreased when miRNA-124 was successfully upregulated, while the expression of AR significantly increased; however, the function of AR was also inhibited when T concentration in the culture medium was increased. This study has proved that SRSFs are regulated by corresponding miRNAs, and the altered expression of SRSFs interferenced the alternative splicing process of AR and ultimately decreased the function of AR, leading to the accumulation of androgens in the ovary.

A Novel Computational Model for Predicting microRNA-Disease Associations Based on Heterogeneous Graph Convolutional Networks

Identifying the interactions between disease and microRNA (miRNA) can accelerate drugs development, individualized diagnosis, and treatment for various human diseases. However, experimental methods are time-consuming and costly. So computational approaches to predict latent miRNA-disease interactions are eliciting increased attention. But most previous studies have mainly focused on designing complicated similarity-based methods to predict latent interactions between miRNAs and diseases. In this study, we propose a novel computational model, termed heterogeneous graph convolutional network for miRNA-disease associations (HGCNMDA), which is based on known human protein-protein interaction (PPI) and integrates four biological networks: miRNA-disease, miRNA-gene, disease-gene, and PPI network. HGCNMDA achieved reliable performance using leave-one-out cross-validation (LOOCV). HGCNMDA is then compared to three state-of-the-art algorithms based on five-fold cross-validation. HGCNMDA achieves an AUC of 0.9626 and an average precision of 0.9660, respectively, which is ahead of other competitive algorithms. We further analyze the top-10 unknown interactions between miRNA and disease. In summary, HGCNMDA is a useful computational model for predicting miRNA-disease interactions.

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.

Role of microRNA in the Pathogenesis of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most typical metabolic syndrome in women of reproductive age, with a high prevalence and an increased risk of long-term complications. PCOS mainly manifests as hyperandrogenism (HA), ovulatory dysfunction, and polycystic ovaries, in addition to being relevant to infertility, insulin resistance (IR), obesity, lipid abnormalities, and chronic low-grade inflammation. The etiology of this syndrome remains largely unknown. microRNAs (miRNAs), small, noncoding RNAs (nearly 22 nucleotides long), regulate gene expression at the posttranscriptional level. Abnormal miRNA levels are closely associated with the occurrence of diseases, such as diabetes, cancers, and atherosclerosis, and miRNAs can be used as predictors and diagnostic biomarkers for cancer. Interestingly, the roles of miRNAs in PCOS pathology have attracted considerable attention in recent years. Research has established that alterations in miRNA expression in women with PCOS compared with healthy women may act as noninvasive biomarkers and new therapeutic targets in PCOS. This article aims to summarize the latest research on the relationship between miRNAs and the clinical manifestations of PCOS while also providing a few mechanisms based on previous studies. Understanding the relationship between miRNAs and PCOS will provide guidance for researchers to further explore the complexity and heterogeneity of PCOS.

Chronically elevated androgen and/or consumption of a Western-style diet impairs oocyte quality and granulosa cell function in the nonhuman primate periovulatory follicle

PURPOSE

To investigate the impact of chronically elevated androgens in the presence and absence of an obesogenic diet on oocyte quality in the naturally selected primate periovulatory follicle.

METHODS

Rhesus macaques were treated using a 2-by-2 factorial design (n = 10/treatment) near the onset of menarche with implants containing either cholesterol (C) or testosterone (T, 4-5-fold increase above C) and a standard or "Western-style" diet alone (WSD) or in combination (T+WSD). Following ~ 3.5 years of treatment, females underwent controlled ovulation (COv, n = 7-10/treatment) cycles, and contents of the naturally selected periovulatory follicle were aspirated. Follicular fluid (FF) was analyzed for cytokines, chemokines, growth factors, and steroids. RNA was extracted from luteinizing granulosa cells (LGCs) and assessed by RNA-seq.

RESULTS

Only healthy, metaphase (M) I/II-stage oocytes (100%) were retrieved in the C group, whereas several degenerated oocytes were recovered in other groups (33-43% of T, WSD, and T+WSD samples). Levels of two chemokines and one growth factor were reduced (p < 0.04) in FF of follicles with a MI/MII oocyte in WSD+T (CCL11) or T and WSD+T groups (CCL2 and FGF2) compared to C and/or WSD. Intrafollicular cortisol was elevated in T compared to C follicles (p < 0.02). Changes in the expression pattern of 640+ gene products were detected in LGC samples from follicles with degenerated versus MI/MII-stage oocytes. Pathway analysis on RNAs altered by T and/or WSD found enrichment of genes mapping to steroidogenic and immune cell pathways.

CONCLUSIONS

Female primates experiencing hyperandrogenemia and/or consuming a WSD exhibit an altered intrafollicular microenvironment and reduced oocyte quality/competency, despite displaying menstrual cyclicity.

Bioinformatics identification of microRNAs involved in polycystic ovary syndrome based on microarray data

Polycystic ovary syndrome (PCOS) is the most common endocrine disease in women of reproductive age. MicroRNAs (miRNAs or miRs) serve important roles in the physiological and pathological process of PCOS. To identify PCOS-associated miRNAs, the dataset GSE84376 was extracted from the Gene Expression Omnibus database. Differentially expressed miRNAs (DE-miRNAs) were obtained from Gene-Cloud Biotechnology Information and potential target genes were predicted using TargetScan, DIANA-microT-CDS, miRDB and miRTarBase tools. Gene Ontology enrichment analysis was performed using Metascape and a protein-protein interaction network was constructed using Cytoscape. Transcription factors were obtained from FunRich. DE-miRNAs were verified by reverse transcription-quantitative PCR. At the screening phase, there were seven DE-miRNAs in the PCOS group not present in the control group. In total, 935 target genes were identified, which are involved in the development and maturation of oocytes. Mitogen-activated protein kinase 1, phosphatase and tensin homolog, cAMP responsive element binding protein 1, signal transducer and activator of transcription 3, interferon γ, Fms-related tyrosine kinase 1, transcription factor p65, insulin receptor substrate 1, DnaJ homolog superfamily C member 10 and casein kinase 2 α 1 were identified as the top 10 hub genes in the protein-protein interaction network. Specificity protein 1 was the most enriched transcription factor. At the validation phase, the levels of Homo sapiens (hsa)-miR-3188 and hsa-miR-3135b were significantly higher in the PCOS group than in the control group. In addition, the expression level of hsa-miR-3135b was significantly correlated with the number of oocytes retrieved, the fertilization rate and the cleavage rate (P<0.05). The present bioinformatics study on miRNAs may offer a novel understanding of the mechanism of PCOS, and may serve to identify novel miRNA therapeutic targets.

The role of MiRNA in polycystic ovary syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder in reproductive-aged women. Clinical manifestations include hyperandrogenism, chronic anovulation, polycystic ovaries and being frequently accompanied by insulin resistance (IR) and obesity. MicroRNAs (miRNAs) are short non-coding RNAs which are involved in the regulation of gene expression at the post-transcriptional level. Altered miRNAs levels have been showed to be associated with a variety of diseases including diabetes, endometriosis and cancer. In recent years, more and more evidence suggests abnormal expression of miRNAs are detected in granulosa cells, theca cells, adipose tissue, follicular fluid, serum and peripheral blood leukocytes of women with PCOS and display vital role in the occurrence and development of PCOS. This will shed light on new strategies for the diagnosis and treatment of this syndrome. In this paper, we will review the recent research on miRNAs with respect to PCOS.

MicroRNA-9 affects isolated ovarian granulosa cells proliferation and apoptosis via targeting vitamin D receptor

MicroRNAs (miRNAs or miRs)-9 expression was reported to be upregulated in the follicular fluid of patients with polycystic ovary syndrome (PCOS). However, whether miR-9 affects ovarian dysfunction of PCOS and the related mechanisms are still unclear. Here we detected miR-9 and vitamin D receptor (VDR) expression in women with PCOS and controls, and investigated whether miR-9 affects ovarian granulosa cells (GCs) proliferation and apoptosis by targeting VDR. We found increased miR-9 and decreased VDR in the blood and isolated ovarian GCs of women with PCOS compared with the controls. MiR-9 promoted GCs proliferation and inhibited GCs apoptosis in vitro, and these effects were attenuated by its target VDR. High concentrations of insulin upregulated miR-9 expression in GCs. In conclusion this study firstly proved miR-9 affects ovarian GCs proliferation and apoptosis through targeting VDR. MiR-9 might be a potential molecular target for improving the dysfunction of GCs in PCOS.

Circular RNA expression profiling of granulosa cells in women of reproductive age with polycystic ovary syndrome

Purpose

This study aimed to explore the expression profiles of circRNA in granulosa cells of women of reproductive age with polycystic ovary syndrome (PCOS).

Methods

Total RNA was isolated from granulosa cells of 15 women with PCOS and 15 body mass index- and age-matched healthy women (control). RNA sequencing was conducted on ribosomal-depleted RNA for circRNA expression profiling. The differential expression of circRNA between women with PCOS and controls was compared and visualized using hierarchical clustering heat maps and Volcano plots. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed to determine the role of the differential expression of circRNAs. The expression rates of circRNAs were confirmed using quantitative real-time PCR (qRT-PCR) using divergent primers.

Results

A total of 4258 and 7395 candidate circRNAs were predicted in PCOS and controls, respectively, based on the RNA-sequencing data. Differences were noted in the expression patterns of circRNA between the two groups. Analysis of the expression profiles revealed that four circRNAs were upregulated, whereas 23 were downregulated in the women with PCOS. GO analysis suggested that the 27 differentially expressed circRNAs were mainly distributed in biological process pathways, particularly in pathways involving inflammation, proliferation, and the vascular endothelial growth factor-related signaling pathway. Six circRNAs were identified in PCOS-affected women using divergent primers. qRT-PCR confirmed that hsa_circ_0001577 was significantly upregulated and hsa_circ_0020093 was downregulated in the women with PCOS.

Conclusions

Several circRNAs were differentially expressed in women of reproductive age with PCOS, suggesting the involvement of these circRNAs in the development of PCOS and the potential clinical implications of their use as PCOS biomarkers.

Electronic supplementary material

The online version of this article (10.1007/s00404-019-05129-5) contains supplementary material, which is available to authorized users.

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.

Identification of microRNAs in granulosa cells from patients with different levels of ovarian reserve function and the potential regulatory function of miR-23a in granulosa cell apoptosis

This study aimed to determine the microRNA (miRNA) profiles in granulosa cells (GCs) from the follicular fluid (FF) of patients with varying levels of ovarian reserve function. We included 45 women undergoing in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatment. After collecting GCs from each patient, total RNA was extracted from 12 samples. Using Illumina/deep-sequencing technology, we analyzed the small RNAs in each group. Using the R package, we identified the differentially expressed (DE) miRNAs among patients with varying levels of ovarian reserve function. We identified 20 conserved and 3 novel miRNAs that were upregulated in the poor ovarian response (POR) group and 30 conserved miRNAs and 1 novel miRNA that were upregulated in the polycystic ovary syndrome (PCOS) group. Bioinformatics analysis revealed complementary pairing between miR-23a and the 3'-untranslated region (UTR) of the Sirt1 mRNA. miR-23a can regulate SIRT1 protein expression at the posttranscriptional level in GCs. Overexpressing miR-23a can inhibit the expression of SIRT1, decrease the stimulatory effect of SIRT1 on the ERK1/2 pathway, inhibit the expression of p-ERK1/2, and increase apoptosis in GCs. Previous studies confirmed that miR-23a targets SIRT1 and promotes apoptosis in GCs by inhibiting the ERK1/2 signaling pathway. This study provides a novel perspective regarding the role of miRNAs in the regulation of human GC apoptosis in vitro.

MiRNA-99a can regulate proliferation and apoptosis of human granulosa cells via targeting IGF-1R in polycystic ovary syndrome

PURPOSE

We aimed to evaluate the regulation of miR-99a to the biological functions of granulosa cells in polycystic ovary syndrome (PCOS) via targeting IGF-1R.

METHODS

We collected aspirated follicular fluid in both patients with and without PCOS. Granulosa cells (GCs) were isolated through Percoll differential centrifugation to detect both miR-99a and IGF-1R expressions. We further transfected COV434 cells with miR-99a mimics to establish a miRNA-99a (miR-99a) overexpression model. We explored the regulation of miR-99a to the proliferation and apoptosis of human GCs via IGF-1R in COV434. The effect of different insulin concentrations on miR-99a expression was also evaluated.

RESULTS

MiR-99a was significantly downregulated while IGF-1R was upregulated in patients with PCOS. MiR-99a can regulate IGF-1R on a post-transcriptional level. After transfection of miR-99a mimics, the proliferation rate was decreased and apoptosis rate was increased significantly in COV434. Exogenous insulin-like growth factor 1 (IGF-1) treatment could reverse the effect of miR-99a. MiR-99a was negatively and dose-dependently regulated by insulin in vitro.

CONCLUSIONS

MiR-99a expression was downregulated in patients with PCOS, the degree of which may be closely related to insulin resistance and hyperinsulinemia. MiR-99a could attenuate proliferation and promote apoptosis of human GCs through targeting IGF-1R, which could partly explain the abnormal folliculogenesis in PCOS.

Roles of microRNAs in mammalian reproduction: from the commitment of germ cells to peri-implantation embryos

MicroRNAs (miRNAs) are active regulators of numerous biological and physiological processes including most of the events of mammalian reproduction. Understanding the biological functions of miRNAs in the context of mammalian reproduction will allow a better and comparative understanding of fertility and sterility in male and female mammals. Herein, we summarize recent progress in miRNA‐mediated regulation of mammalian reproduction and highlight the significance of miRNAs in different aspects of mammalian reproduction including the biogenesis of germ cells, the functionality of reproductive organs, and the development of early embryos. Furthermore, we focus on the gene expression regulatory feedback loops involving hormones and miRNA expression to increase our understanding of germ cell commitment and the functioning of reproductive organs. Finally, we discuss the influence of miRNAs on male and female reproductive failure, and provide perspectives for future studies on this topic.

Serum miRNAs in women affected by hyperandrogenic polycystic ovary syndrome: the potential role of miR-155 as a biomarker for monitoring the estroprogestinic treatment

MicroRNAs can be used as very efficient circulating biomarkers. The role of microRNAs in polycystic ovary syndrome (PCOS) and the effects of antiandrogen therapy on microRNA expression is still not fully understood. A panel of serum microRNAs were retrotranscribed via looped reverse primer transcription specific for each miRNA and quantified via probe specific RT-PCR in 16 Caucasian hyperandrogenic PCOS women selected according to the Rotterdam criteria and in a subset of seven patients after four months of sequential reverse antiandrogenic therapy. All women recruited underwent an oral glucose tolerance test (OGTT) and a baseline total cholesterol, high density lipoproteins cholesterol, triglycerides, AST and ALT dosage. In the follicular phase women were evaluated for total testosterone, Δ4-androstenedione, DHEAS, 17OHpg, FSH, LH, and 17-β-E2. The AUC_2hglucose, ISI Matsuda, oral disposition index (DIo) and visceral adipose index (VAI) were also calculated. We suggest that miR-155 might have a role as biomarker in hyperandrogenic PCOS patients to monitor the effect of antiandrogen therapy.

Ovarian extracellular MicroRNAs as the potential non-invasive biomarkers: An update

Through the reproductive system, it has been realized that the microRNAs (miRNAs) have emerged as one of the principal post-transcriptional gene regulators of the diverse developmental processes. The ovary, as a dynamic organ, co-ordinates follicle recruitment, selection, and ovulation, in which miRNAs play the central role almost in its all functions. Deregulation of these developmental procedures in ovary could lead to the ovarian dysfunction, infertility, decrease in the assisted reproductive treatment (ART) outcome, and death in some patients with ovarian cancer. In recent years, detection of ovarian extracellular miRNAs in body fluids such as follicular fluid and serum/plasma has opened a new era in the biomarker discovery field. Here through the present review, different aspects of the potential and proposed involvement of the extracellular miRNAs in both physiologic and pathologic contexts of the ovary have been discussed. Moreover, the researchers have addressed the relevant findings, challenges, and issues which associated with the extracellular miRNAs in the ovarian microenvironments to provide the better insight into understanding the molecular mechanisms which were involved in the pathophysiologic conditions. Finally, a comprehensive survey of the gaps has been discussed to hopefully shed new light and perspective on the development of the novel diagnostic and therapeutic platforms in the clinic.

Micro-RNAs involved in cellular proliferation have altered expression profiles in granulosa of young women with diminished ovarian reserve

PURPOSE

The study aims to determine differences in micro-RNA (miRNA) expression in granulosa (GC) and cumulus cells (CC) between young women with diminished ovarian reserve (DOR) or normal ovarian reserve (NOR). Secondary objective was to identify downstream signaling pathways that could ultimately indicate causes of lower developmental competence of oocytes from young women with DOR.

METHODS

The method of the study is prospective cohort study.

RESULTS

Of the miRNA, 125 are differentially expressed in GC between DOR and NOR. Only nine miRNA were different in CC; therefore, we focused analysis on GC. In DOR GC, miR-100-5p, miR-16-5p, miR-30a-3p, and miR-193a-3p were significantly downregulated, while miR-155-5p, miR-192-5p, miR-128-3p, miR-486-5p, miR130a-3p, miR-92a-3p, miR-17-3p, miR-221-3p, and miR-175p were increased. This pattern predicted higher cell proliferation in the DOR GC. The primary pathways include MAPK, Wnt, and TGFbeta.

CONCLUSIONS

The miRNA pattern identified critical functions in cell proliferation and survival associated with DOR. GC in women with DOR seems to respond differently to the LH surge.

Stage-specific follicular extracellular vesicle uptake and regulation of bovine granulosa cell proliferation

Follicular fluid within ovarian antral follicles contains numerous factors, which influence the development of a healthy oocyte including nucleic acids, steroids, proteins, and extracellular vesicles (EVs). Current evidence indicates that follicular EVs promote changes in cellular gene expression and support cumulus-oocyte complex expansion in vitro. In this study, we found EVs from different sized follicles differentially stimulate granulosa cell proliferation and this could be explained by both the differential contents associated, on or within the vesicles and by the preferential uptake of EVs dependent on follicle size from which they were isolated. Antibody array and inhibitor studies indicated that the Src, PI3K/Akt, and MAPK signaling pathways mediate the stimulatory effects of EVs on granulosa cell proliferation. This study demonstrates for the first time that EVs isolated from follicular fluid are capable of stimulating granulosa cell proliferation and that this stimulatory response is associated with the size of antral follicle from which the EVs originated. The study further also provides the first evidence that vesicles released by small antral follicles are preferentially taken up when compared to those isolated from large follicles, suggesting that vesicular surface proteins change during follicular maturation.

Identification of microRNAs and genes associated with hyperandrogenism in the follicular fluid of women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disease, which is characterized by hyperandrogenism (HA), chronic anovulation, polycystic ovaries, insulin resistance, and obesity. At present, the mechanism by which PCOS/HA occurs has not been fully elucidated, thus, the mechanisms behind and interventions for HA in PCOS are current hot topics in research. MiRNAs have recently been shown to serve as diagnostic or prognostic biomarkers in patients with cancer. Thus, we are currently focused on studying the altered expression of miRNAs in follicular fluid and their correlation with HA in PCOS. Illumina deep sequencing technology was used to explore different miRNAs in the follicular fluid of women with PCOS/HA and in the follicular fluid of women in a control group. Target prediction databases were then used to analyse the target genes of different expressed miRNAs, and GO analysis and the KEGG pathway database were used to identify the functions and the main biochemical and signalling pathways of differentially expressed target genes. The expression levels of 263 miRNAs were significantly different (>2-fold up-regulated or <0.5-fold down-regulated, P < 0.05) between the two groups of women. For example, the expression levels of miRNA (200a-3p, 10b-3p, 200b-3p, 29c-3p, 99a-3p, and 125a-5p) were significantly increased, while there was a decreased expression of miR-105-3p in PCOS patients with respect to the control. Literature has shown that the above seven miRNAs were associated with HA in PCOS. Furthermore, 31 770 genes were predicted to be targets of the 263 differentially expressed microRNAs. GO analysis and the KEGG pathway database showed involvement of these target genes in HA in PCOS. These results suggest the presence of differentially expressed miRNAs in the follicular fluid of women with PCOS/HA versus women in the control group. The potential role of these microRNAs was elucidated using bioinformatics tools and was found to be involved in the regulation of different pathways, biological functions, and cellular components underlying PCOS. The results of this research may reveal new mechanisms of PCOS/HA and suggest potential treatment targets.

Functional Characterization of MicroRNA-27a-3p Expression in Human Polycystic Ovary Syndrome

The goal of this study was to characterize the function of microRNA-27a-3p (miR-27a-3p) in polycystic ovary syndrome (PCOS). miR-27a-3p expression was analyzed in excised granulosa cells (GCs) from 21 patients with PCOS and 12 normal patients undergoing in vitro fertilization cycle treatments and in 17 nontreated cuneiform ovarian resection PCOS samples and 13 control ovarian samples from patients without PCOS. We found that the expression of miR-27a-3p was significantly increased in both excised GCs and the ovaries of patients with PCOS compared with the controls. Insulin treatment of the human granulosa-like tumor cell line (KGN) resulted in decreased downregulated expression of miR-27a-3p, and this effect appeared to be mediated by signal transducer and activator of transcription STAT1 and STAT3. The overexpression of miR-27a-3p in KGN cells inhibited SMAD5, which in turn decreased cell proliferation and promoted cell apoptosis. After KGN cells were stimulated with insulin for 48 hours, there was increased expression of SMAD5 protein and decreased apoptosis. Additionally, knockdown/overexpression of SMAD5 in KGN cells reduced/increased cell number and promoted/inhibited cell apoptosis. Insulin-stimulated primary GCs isolated from patients with PCOS, in contrast to normal GCs or KGN cells, did not exhibit decreased miR-27a-3p expression. The differences in the expression levels in KGN cells and human PCOS GCs are likely explained by increased miR-27a-3p expression in the GCs caused by insulin resistance in PCOS. Taken together, our data provided evidence for a functional role of miR-27a-3p in the GCs' dysfunction that occurs in patients with PCOS.

MiR-101 inhibits ovarian carcinogenesis by repressing the expression of brain-derived neurotrophic factor

Ovarian cancer is one of the most lethal malignant gynecological tumors as a result of difficulties in early‐stage detection and a lack of effective treatments for patients with advanced or recurrent cancer. In the present study, we aimed to explore whether some of the microRNA (miRNA) content of serum might be related to ovarian cancer, as well as the role of these miRNAs and their intercellular transport via exosomes in ovarian cancer. We first detected the expression of six candidate miRNAs in ovarian cancer tissues and adjacent nontumor ovarian samples from 36 patients and confirmed the altered expression of four miRNAs. The level of these six candidate miRNAs was also examined in exosomes from patient serum samples. Only the level of miR‐101 was altered in both ovarian tissue samples and serum exosomes. After prediction using online bioinformatics tools and confirmation by dual‐luciferase assay and immunoblotting, we identified that miR‐101 can repress the expression of brain‐derived neurotrophic factor by targeting its 3′‐UTR. Using Transwell assays, we examined the effect of miR‐101 on migration and invasion capacity of ovarian cancer cells. The results indicated that the reduction of miR‐101 is mostly related to significant enhanced ovarian cancer cell migration. Thus, the results of the present study indicate that miR‐101 content in serum exosomes has potential as a marker for diagnosis of ovarian cancer and that miR‐101 mimics are potential therapeutic drugs for the treatment of ovarian cancer.

MicroRNA‑320a inhibition decreases insulin‑induced KGN cell proliferation and apoptosis by targeting PCGF1

MicroRNAs (miRNAs) are widely involved in regulation of cellular processes of polycystic ovary syndrome (PCOS). However, the function of miR‑320a in PCOS remains unclear. The present study aimed to explore the effect of miR‑320a on PCOS cell proliferation and apoptosis following treatment with insulin, and to clarify the underlying mechanism. PCOS tissues and corresponding normal tissues were collected from 16 female patients with PCOS. KGN cells were pre‑treated with insulin, and KGN cells were transfected with ASO‑miR‑320a, miR‑320a mimics and polycomb group ring finger 1 (PCGF1) overexpression plasmids. Expressions of miR‑320a and PCGF1 were detected using the reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). Dual‑Luciferase reporter assays were performed to investigate the target gene of miR‑320a. MTS, colony formation and flow cytometry assays were performed to determine cell viability, colony formation, and apoptosis, respectively. Furthermore, mRNA and protein expression levels of B‑cell lymphoma 2 apoptosis regulator (Bcl‑2) and Bcl‑2 associated protein X apoptosis regulator (Bax) were examined using RT‑qPCR and western blotting. The results demonstrated that miR‑320a expression was significantly increased in PCOS tissues compared with normal tissues. Moreover, miR‑320a was upregulated in insulin‑induced cells in a dose‑dependent manner. Inhibition of miR‑320a suppressed insulin‑induced cell viability and colony formation, and promoted apoptosis. Luciferase reporter assays demonstrated that PCGF1 was a target of miR‑320a. Additionally, PCGF1 overexpression inhibited cell viability and colony formation and promoted apoptosis. Additionally, the mRNA and protein levels of Bcl‑2 were inhibited by miR‑320a suppression and PCGF1 overexpression, while Bax expression was promoted by them in insulin‑induced cells. The results of the present study demonstrated that miR‑320a inhibition decreased insulin‑induced KGN cell proliferation and apoptosis by targeting PCGF1. These data indicated that miR‑320a may serve as a potential diagnostic biomarker for PCOS.

[Quality of oocytes and embryos from women with polycystic ovaries syndrome: State of the art]

The frequency of polycystic ovary syndrome (PCOS) and the consequent fertility disorders cause many difficulties in the management of the assisted reproductive technics. Some studies are focused on different additional treatments, stimulation protocols or techniques that could optimize the in vitro fertilization cycles. The quality of the oocytes and embryos of these patients is also an outstanding issue. They remain difficult to actually evaluate during management, and none of the few published studies on this subject demonstrated any inferiority, compared to control patients. However, many differences have been highlighted, studying intra- and extra-ovarian factors. The advent of new genetic techniques could allow a better understanding of the pathophysiological mechanisms of the syndrome, as well as refining the evaluation of oocytes and embryos, in order to better predict the results of in vitro fertilization attempts. Pregnancy and birth rates, however, appear to be comparable to those of the general population.

Abnormality of Klotho Signaling Is Involved in Polycystic Ovary Syndrome

This study investigated the involvement of the klotho-associated signaling in the apoptosis of granulosa cells (GCs) from the ovaries of patients with polycystic ovary syndrome (PCOS) and PCOS animals. Primary GCs were obtained from 26 healthy women and 43 women with PCOS. The PCOS animal model was established by the injection of dehydroepiandrosterone (DHEA). Klotho protein and associated microRNA expression in human primary GCs and rats' ovarian tissues were measured by Western blot and real-time polymerase chain reaction, respectively. Results showed that significantly lower miR-126-5p and miR-29a-5p microRNA expressions, higher klotho protein expression, lower insulin growth factor 1 (IGF-1R) and Wnt family member 1 (Wnt1) protein expressions, and lower Akt phosphorylation at Ser⁴⁷³ and Thr³⁰⁸ residues were observed in the GCs from patients with PCOS and the ovarian tissues of PCOS rats compared to that in GCs from healthy women and ovarian tissues of normal control rats, respectively. Knockdown of klotho gene expression normalized IGF-1R and Wnt1 protein expressions and Akt phosphorylation in GCs from patients with PCOS and the ovarian tissues from PCOS rats; it also blocked the effects of insulin on apoptosis and proliferation in GCs from patients with PCOS and inhibited caspase-3 activity in ovarian tissues of PCOS rats. Knockdown of klotho gene expression increased the pregnancy rate in DHEA-treated female rats and increased the body weight of their newborns through normalizing the ovarian function and decreasing the formation of cystic follicles. In conclusion, the miR-126-5p, miR-29a-5p/klotho/insulin-IGF-1, Wnt, and Akt signal pathway may be involved in the apoptosis of GCs and subsequent development of PCOS.

Which origin for polycystic ovaries syndrome: Genetic, environmental or both?

Polycystic ovaries syndrome (PCOS), the most common female endocrine disorder, affects 7-10% of women of childbearing age. It includes ovarian hyperandrogenism, impaired follicular maturation, anovulation and subfertility. Insulin resistance, although present in most cases, is not necessary for diagnosis. It increases hyperandrogenism and long-term metabolic, cardiovascular and oncological risks. The origin of hyperandrogenism and hyperinsulinemia has a genetic component, as demonstrated by familial aggregation studies and recent identification of associated genomic variants, conferring a particular susceptibility to the syndrome. However, experimental and epidemiological evidences also support a developmental origin via a deleterious foetal environment, concerning the endocrine status (foetal hyperandrogenism), the nutritional level (intrauterine growth retardation), or the toxicological exposure (endocrine disruptors). Epigenetic changes recently reported in the literature as associated with PCOS, enhance this hypothesis of foetal reprogramming of the future adult ovarian function by environmental factors. Better characterisation of these genetic, epigenetic, or environmental factors, could lead to earlier prevention and more efficient treatments.

Non‑coding RNAs and ovarian diseases (Review)

Non-coding RNAs (ncRNAs) are a diverse family of untranslated transcripts, which serve important roles in numerous biological processes. ncRNAs are emerging as major mediators of gene expression with crucial regulatory functions. Ovarian diseases have a wide variety of clinical pathological types, which have serious impacts on women's health. In this review, current studies on ncRNAs are summarized with respect to ovarian diseases. Understanding of the role of ncRNAs in ovarian diseases is currently limited; further studies on the molecular mechanisms by which abnormal expression of ncRNAs contributes to ovarian diseases will aid in the identification of ncRNAs as novel diagnostic markers and therapeutic targets for ovarian diseases.

Oocyte Competence in Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age and affects fertility and pregnancy in cases of oligoanovulation. Ovulation induction is often used to treat anovulatory patients with PCOS, but many of these women fail to conceive and resort to assisted reproductive technologies. Alterations in oocyte competence (OC) are considered potential causative factors for subfertility in women with PCOS. In this review we present and critically assess all recent clinical and experimental data regarding OC in women with PCOS. Our analysis demonstrates that the contribution of OC to reproductive potential in women with PCOS varies and largely depends on the PCOS phenotype and comorbidities associated with PCOS.

miR-142-3p as a biomarker of blastocyst implantation failure - A pilot study

OBJECTIVE

This study aims to find whether microRNAs (miRNAs) detected in the culture medium of embryos produced in vitro could be potential biomarkers of embryo implantation.

METHODS

Culture media samples from 36 embryos, derived from patients undergoing intracytoplasmic sperm injection (ICSI) in a private university-affiliated IVF center, were collected between January/2015 and November/2015. Samples were collected on day three and embryo transfers were performed on day five and all embryos reached the blastocyst stage. Samples were split into groups according to the embryo implantation result: Positive-Implantation-Group (n=18) or Negative-Implantation-Group (n=18). For the first analysis, samples were pooled in three sets for each group (6-7 spent media per pool). MicroRNAs were extracted from spent media and cDNA was synthesized. C. elegans miR-39 was used as RNA spike-in to normalize the gene expression analysis. The expression of microRNAs into the spent media from the Positive-Implantation-Group was compared with those from the Negative-Implantation-Group. A set of seven miRNAs (miR-21, miR-142-3p, miR-19b, miR-92a, miR-20b, miR-125a and miR148a) selected according with the literature, was tested. To check whether miRNAs could be detected in individual samples of culture media, in a second analysis, ten more samples were tested for miR-21 and miR-142-3p.

RESULTS

From the sevens tested miRNAs, a significant increased expression of miR-142-3p could be noted in the Negative-Implantation-Group (P<0.001). For other three miRNAs (miR-21, miR-19b and miR-92a) a difference in expression was observed, however it did not reach a statistical significance. In addition, when ten non-redundant samples were tested to check if miRNAs could be detected in individual samples of culture media, the highly specific amplification of mature miRNAs, including miR-142-3p, could be noted.

CONCLUSION

Our findings suggest that miR-142-3p, previously described as a tumor suppressor and cell cycle inhibitor, may be a potential biomarker of blastocyst implantation failure. The identification of miRNAs on individual culture medium samples offers unique opportunities for non-invasive early diagnosis of blastocyst implantation.

Inside the granulosa transcriptome

The somatic component of follicular structure is a mixture of different cell types, represented by Granulosa cells (GCs) that are the paracrine regulators of the oocyte growth. GCs finely support this process by a continuous bidirectional talk with oocyte, which ensure oocyte quality and competence. Specific pathways are involved in the cross-talk and in both GCs and oocyte development. This review summarizes data from GCs gene expression analysis concerning both their physiological role and their interaction with oocyte. We also explore the CGs transcriptome modifications induced by controlled ovarian stimulation (COS) or pathological conditions and their impact in reproduction. The transcriptome analysis of GCs could be a powerful tool to improve our knowledge about the pathways involved in oocyte development. This approach, associated with new technologies as RNA-seq could allow the identifications of new noninvasive biological markers of oocyte quality to increase the efficiency of clinical IVF. Moreover, GCs expression analysis could be useful to shed light on new therapeutic targets by providing new options for the treatment of infertility.

The Role of Serum MicroRNA-6767-5p as a Biomarker for the Diagnosis of Polycystic Ovary Syndrome

Background

Polycystic ovary syndrome (PCOS) is a heterogeneous disorder, and the underlying molecular mechanisms are not clear. To date, few studies have been conducted on the altered expression of serum microRNAs (miRNAs) in women with PCOS. The present study was performed to examine the role of the serum miRNA as a biomarker for the diagnosis of PCOS and its relationship with metabolic and reproductive traits.

Methods

A cross-sectional comparison was made in 21 women with PCOS and age- and body mass index (BMI)- matched 21 healthy women in an academic center laboratory between December 2008 and October 2010. We selected miRNAs that were more than 1.5-fold up-regulated or less than 0.67-fold down-regulated in women with PCOS compared with controls using the SurePrint G3 Human miRNA Microarray. Subsequently, we validated the relative expression of the miRNAs using TaqMan quantitative real-time polymerase chain reaction (RT-qPCR) assays.

Results

Serum miRNA-4522, miRNA-324-3p, and miRNA-6767-5p were down-regulated in women with PCOS compared with controls in the microarray analysis. Among these miRNAs, serum miRNA-6767-5p was validated (fold change in women with PCOS/controls = 0.39, P-value<0.05) by RT-qPCR. The miRNA-6767-5p was negatively associated with fasting glucose (β = -0.370) and positively associated with the number of menses per year (β = 0.383) after adjustment for age and BMI (Ps<0.05). Genes targeted by miRNA-6767-5p were involved in the cell cycle and the immune system.

Conclusions

Serum miRNA-6767-5p may be a novel candidate as a molecular biomarker in the diagnosis of PCOS and may participate in the development of the metabolic and reproductive traits of PCOS.

MicroRNAs related to androgen metabolism and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a frequent endocrine disorder in women. PCOS is associated with altered features of androgen metabolism, increased insulin resistance and impaired fertility. Furthermore, PCOS, being a syndrome diagnosis, is heterogeneous and characterized by polycystic ovaries, chronic anovulation and evidence of hyperandrogenism, as well as being associated with chronic low-grade inflammation and an increased life time risk of type 2 diabetes. A number of androgen species contribute to the symptoms of increased androgen exposure seen in many, though not all, cases of PCOS: Testosterone, androstenedione, dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS), where the quantitatively highest amount of androgen is found as DHEAS. The sulfation of DHEA to DHEAS depends on a number of enzymes, and altered sulfate metabolism may be associated with and contribute to the pathogenesis of PCOS. MicroRNAs (miRNAs) are small, non-coding RNAs that are able to regulate gene expression at the post-transcriptional level. Altered miRNA levels have been associated with diabetes, insulin resistance, inflammation and various cancers. Studies have shown that circulating miRNAs are present in whole blood, serum, plasma and the follicular fluid of PCOS patients and that these might serve as potential biomarkers and a new approach for the diagnosis of PCOS. In this review, recent work on miRNAs with respect to PCOS will be summarized. Our understanding of miRNAs, particularly in relation to PCOS, is currently at a very early stage, and additional studies will yield important insight into the molecular mechanisms behind this complex and heterogenic syndrome.