# Reduced miR-338-3p contributes to polycystic ovarian syndrome by inhibiting proliferation and enhancing apoptosis

## TL;DR

This study shows that lower levels of miR-338-3p in PCOS patients may lead to ovarian issues by reducing cell growth and increasing cell death.

## Contribution

The study reveals a novel role of miR-338-3p in PCOS through its regulation of PTEN and effects on granulosa cell function.

## Key findings

- miR-338-3p levels are reduced in PCOS patients and correlate negatively with LH and testosterone.
- Lower miR-338-3p inhibits granulosa cell proliferation and promotes apoptosis.
- miR-338-3p regulates PTEN, and PTEN inhibition reverses the effects of miR-338-3p downregulation.

## Abstract

Polycystic ovarian syndrome (PCOS) is a frequently occurring disorder affecting reproductive and metabolic health. miR-338-3p is implicated in early follicular development. We aimed to investigate the expression of miR-338-3p in PCOS patients and its effects on proliferation and apoptosis of ovarian granulosa cells.

The study included 100 healthy women and 110 women diagnosed with PCOS as participants. Reverse transcription quantitative PCR (RT-qPCR) was used to detect the expression of miR-338-3p and phosphatase and tensin homolog (PTEN), and receiver operating characteristic (ROC) was employed to evaluate the diagnostic efficacy of miR-338-3p. Cell proliferation and apoptosis were detected by Cell Counting Kit-8 (CCK-8) and flow cytometry. Pearson correlation analysis was used to assess the correlations between miR-338-3p and luteinizing hormone (LH), testosterone, or PTEN. The target relationship of miR-338-3p and PTEN was confirmed via dual-luciferase assay.

Serum miR-338-3p was decreased in PCOS patients, and it was negatively correlated with both LH and testosterone. Downregulation of miR-338-3p inhibits the proliferation of ovarian granulosa cells and enhances cell apoptosis, whereas upregulation produces the opposite effect. PTEN inhibition subverted the inhibited proliferation and enhanced apoptosis regulated by miR-338-3p inhibitor.

Reduced miR-338-3p levels have potential predictive value in distinguishing individuals with PCOS patients from normal population. Mechanistically, this microRNA regulates the PTEN gene to inhibit granulosa cell proliferation and promote apoptosis, thereby contributing to the pathological processes of PCOS.