Long non‑coding RNA NEAT1 promotes mouse granulosa cell proliferation and estradiol synthesis by sponging miR‑874‑3p

It has been reported that long non-coding RNA nuclear-enriched abundant transcript 1 (NEAT1) is involved in follicular growth and multiple ovarian diseases, but not the physiological function of NEAT1 in mouse granulosa cells (mGCs). Therefore, the aim of the present study was to investigate the biological roles and regulatory mechanisms of NEAT1 in mGCs. The biological effects of NEAT1 on mGCs proliferation, apoptosis, production of 17β-Estradiol (E2) and progesterone (P4) were investigated using MTS, flow cytometry and enzyme-linked immunosorbent assays, respectively. The association between NEAT1 and microRNA (miR)-874-3p was verified using luciferase reporter assay and RNA immunoprecipitation analysis. The results demonstrated that the knockdown of NEAT1 in mGC cells significantly promoted mGCs cell proliferation, inhibited apoptosis and increased the production of E2 and P4 in mGCs. The interference-mediated effect of NEAT1 on mGCs could be partially reversed by the downregulation of miR-874-3p. Overall, these results indicated that NEAT1 served as a competing endogenous RNA by competitively binding with miR-874-3p, thereby modulating mGCs proliferation and the production of E2 and P4 in mGCs.

MicroRNA-205 affects mouse granulosa cell apoptosis and estradiol synthesis by targeting CREB1

MicroRNA-205 (miR-205) is involved in various physiological and pathological processes, but its biological function in follicular atresia remains unclear. In this study, we investigated miR-205 expression in mouse granulosa cells (mGCs) and analyzed its functions in primary mGCs by performing a series of in vitro experiments. Quantitative real-time polymerase chain reaction showed that miR-205 expression was significantly higher in early atretic follicles and progressively atretic follicles than in healthy follicles. miR-205 overexpression in mGCs significantly promoted apoptosis and caspase-3/9 activities, as well as inhibited estrogen (E2) release and cytochrome P450 family 19 subfamily A polypeptide 1 (CYP19A1, a key gene in E2 production) expression. Bioinformatics and luciferase reporter assays revealed that the gene encoding cyclic AMP response element (CRE)-binding protein 1 (CREB1) was a direct target of miR-205 in mGCs. CREB1 upregulation partially rescued the effects of miR-205 on apoptosis, caspase-3/9 activities, E2 production, and CYP19A1 expression on mGCs. These results indicate that miR-205 might play an important role in ovarian follicular development and provide new insights into follicular atresia.