Experimental polycystic ovarian syndrome is associated with reduced expression and function of P2Y2 receptors in rat theca cells

Purinergic receptor P2X7 activates NOX2/JNK signaling to participate in granulosa cell inflammation and apoptosis in polycystic ovary syndrome

Increasing evidence shows that polycystic ovary syndrome (PCOS) is often accompanied by an inflammatory response, hence, appropriately managing granulosa cell inflammation is critical to regaining ovarian function in PCOS. In this study, the differential levels of purinergic receptor P2X7 between the control and PCOS samples in the dataset GSE34526 were assessed, then PCOS mouse models were established. Following evaluating the fluctuations in hormone levels, inflammatory cytokines, and P2X7, mice received treatment with the P2X7 antagonist A740003. Its effects on hormones, inflammation, apoptosis, and NOX2 signaling in mice were examined. Afterward, primary mouse granulosa cells were isolated, and the mediating role of NOX2 signaling in the P2X7 regulatory pathway was confirmed by transfection of NOX2 overexpression plasmids. The results demonstrated that P2X7 was significantly elevated in the PCOS samples in the dataset. Compared with the control group, PCOS mice had significant differences in the follicle-stimulating hormone, luteinizing hormone, testosterone, anti-Müllerian hormone, inflammatory factors, and P2X7. Treatment with A740003 partially restored these parameter levels, including NOX2 signaling. Based on in vitro experiments on primary mouse granulosa cells, the above findings were re-verified, and the overexpression of NOX2 could reverse the regulatory function of P2X7. The present study highlights that P2X7 level increases in PCOS, and inhibition of P2X7 can reduce disease symptoms. It is involved in inflammation and apoptosis in granulosa cells through NOX2/JNK signaling.

Dysregulated Liver Metabolism and Polycystic Ovarian Syndrome

A significant fraction of couples around the world suffer from polycystic ovarian syndrome (PCOS), a disease defined by the characteristics of enhanced androgen synthesis in ovarian theca cells, hyperandrogenemia, and ovarian dysfunction in women. Most of the clinically observable symptoms and altered blood biomarker levels in the patients indicate metabolic dysregulation and adaptive changes as the key underlying mechanisms. Since the liver is the metabolic hub of the body and is involved in steroid-hormonal detoxification, pathological changes in the liver may contribute to female endocrine disruption, potentially through the liver-to-ovary axis. Of particular interest are hyperglycemic challenges and the consequent changes in liver-secretory protein(s) and insulin sensitivity affecting the maturation of ovarian follicles, potentially leading to female infertility. The purpose of this review is to provide insight into emerging metabolic mechanisms underlying PCOS as the primary culprit, which promote its incidence and aggravation. Additionally, this review aims to summarize medications and new potential therapeutic approaches for the disease.

Construction of a competing endogenous RNA network to identify drug targets against polycystic ovary syndrome

STUDY QUESTION

Would the construction of a competing endogenous RNA (ceRNA) network help identify new drug targets for the development of potential therapies for polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

Both Food and Drug Administartion (FDA)-approved and candidate drugs could be identified by combining bioinformatics approaches with clinical sample analysis based on our established ceRNA network.

WHAT IS KNOWN ALREADY

Thus far, no effective drugs are available for treating PCOS. ceRNAs play crucial roles in multiple diseases, and some of them are in current use as prognostic biomarkers as well as for chemo-response and drug prediction.

STUDY DESIGN, SIZE, DURATION

For the bioinformatics part, five microarrays of human granulosa cells were considered eligible after applying strict screening criteria and were used to construct the ceRNA network for target identification. For population-based validation, samples from 24 women with and without PCOS were collected from January 2021 to July 2021.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The public data included 27 unaffected women and 25 women with PCOS, according to the Rotterdam criteria proposed in 2003. The limma and RobustRankAggreg R packages were used to identify differentially expressed messenger RNAs and noncoding RNAs. Gene Ontology, Reactome and Kyoto Encyclopedia of Genes and Gemomes (KEGG) enrichment analyses were performed. A ceRNA network was constructed by integrating the differentially expressed genes and target genes. The population-based validation included human luteinized granulosa cell samples from 12 unaffected women and 12 women with PCOS. Quantitative real-time polymerase chain reaction was conducted to detect the levels of mRNAs and microRNAs (miRNAs). Connectivity map and computational model algorithms were implemented to predict therapeutic drugs from the ceRNA network. Additionally, we compared the predicted drugs with known clinical medications in DrugBank.

MAIN RESULTS AND THE ROLE OF CHANCE

A set of 10 mRNAs, 11 miRNAs and 53 long non-coding RNAs (lncRNAs) were differentially expressed. Functional enrichment analysis revealed the highest relevance to immune system-related biological processes and signalling pathways, such as cytokine secretion and leucocyte chemotaxis. A ceRNA consisting of two lncRNAs, two miRNAs and five mRNAs was constructed. Through network construction via bioinformatic analysis, we identified some already approved drugs (such as metformin) that could target some molecules in the network as potential drug candidates for PCOS.

LARGE SCALE DATA

Public sequencing data were obtained from GSE34526, GSE84376, GSE102293, GSE106724 and GSE114419, which have been deposited in the Gene Expression Omnibus database.

LIMITATIONS, REASONS FOR CAUTION

Experiments, such as immunoprecipitation, luciferase reporter assays and animal model studies, are needed to validate the potential targets in the ceRNA network before the identified drug candidates can be tested using cellular and animal model systems.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide new bioinformatic insight into the possible pathogenesis of PCOS from ceRNA network analysis, which has not been previously studied in the human reproductive field. Our study also reveals some potential drug candidates for the future development of possible therapies against PCOS.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the National Key Research and Development Program of China (2021YFC2700400) and the National Natural Science Foundation of China (82001498). The authors have no conflicts of interest to disclose.

Functional expression of P2Y2 receptors in mouse ovarian surface epithelium (OSE)

Ovarian surface epithelium (OSE) is a cell monolayer surrounding the ovary; it is involved in the regulation of the ovulatory process and the genesis of ovarian carcinoma. However, intercellular messengers regulating signaling events, like proliferation in the OSE, have not been completely described. Purines have emerged as novel intercellular messengers in the ovary, in which expression of purinergic receptors has been reported in different cell types. In the present work, we described the functional expression of P2Y2 receptor (P2Y2R), a purinergic receptor widely associated with cell proliferation, in the OSE. The expression of P2Y2R by immunofluorescence and RT-PCR, and its functionality by Ca²⁺ recording was demonstrated in primary cultured OSE. Functional expression of P2Y2R was also exhibited in situ, by recording of intracellular Ca²⁺ release and detection of ERK phosphorylation after injection of a selective agonist into the ovarian bursa. Furthermore, P2Y2R activation with UTPγS, in situ, induced cell proliferation at 24 h, whereas continuous stimulation of P2Y2R during a complete estrous cycle significantly modified the size distribution of the follicular population. This is the first evidence of the functional expression of purinergic P2Y2R in the OSE and opens new perspectives on the roles played by purines in ovarian physiology.