MiR-296-3p in Follicular Fluid‑derived Extracellular Vesicles Ameliorates the Ovarian Granulosa Cell Inflammatory Stress Response in Polycystic Ovary Syndrome.

Introduction: This study aimed to determine the expression of microRNA-296-3p (miR- 296-3p) in follicular fluid extracellular vesicles (EVs) of polycystic ovary syndrome (PCOS) patients and its role in regulating ovarian granulosa cell inflammation.

Methods: A case-control study was conducted involving 30 PCOS patients and 30 control subjects. Clinical indicators, including body mass index (BMI), basal luteinizing hormone (LH), and testosterone (T), were measured. The expression level of miR-296-3p in follicular fluid EVs was quantified. Functional assays were performed in LPS-induced ovarian granulosa cells by overexpressing miR-296-3p, and subsequent changes in cell viability and the expression levels of inflammatory cytokines (IL-1α, IL-6, IFN-γ, TNF-α, TGF-β) were analyzed. Bioinformatic analysis identified potential target genes of miR-296-3p.

Results: The PCOS group showed significantly higher BMI, LH, and testosterone levels (P < 0.05). MiR-296-3p expression was markedly downregulated in PCOS follicular fluid EVs (P < 0.01). Its overexpression enhanced granulosa cell viability (P < 0.05), decreased pro-inflammatory cytokines (IL-1α, IL-6, IFN-γ, TNF-α), and increased TGF-β (P < 0.05). We identified 408 potential target genes of miR-296-3p, enriched in inflammation regulation, tumorigenesis, and hormone secretion.

Discussion: Our findings indicate miR-296-3p is significantly downregulated in PCOS and exerts anti-inflammatory effects on granulosa cells, supporting its involvement in PCOS-associated inflammation. The study links miR-296-3p to granulosa cell inflammatory response, though functional validation of target genes remains for future work.

Conclusion: MiR-296-3p is downregulated in PCOS follicular fluid EVs and alleviates granulosa cell inflammation, offering novel insight into PCOS pathogenesis and potential therapeutic targets.