miR-191 regulates porcine granulosa cell functions and modulates responsiveness to FSH

MicroRNAs (miRNAs) are key post-transcriptional regulators of ovarian function, integrating endocrine signals with intracellular pathways to control granulosa cell (GC) fate. Although miR-191 is implicated in ovarian physiology and pathology, its role in porcine GCs and interaction with follicle-stimulating hormone (FSH) remain unclear. Using primary porcine GCs, we examined the effects of miR-191 gain- and loss-of-function on cell viability, proliferation, apoptosis, and progesterone secretion, and assessed its interaction with FSH signaling. MiR-191 overexpression enhanced GC viability and proliferation and suppressed apoptosis, whereas inhibition produced opposite effects. Notably, miR-191 decreased progesterone production, suggesting a shift toward a proliferative rather than differentiated cellular state. FSH upregulated miR-191 expression and stimulated GC proliferation, survival, and progesterone release. Importantly, miR-191 overexpression potentiated the proliferative and anti-apoptotic effects of FSH while attenuating its effect on progesterone production. In silico analyses identified potential targets involved in cell cycle regulation and ovarian function, supporting indirect regulatory mechanisms. These findings identify miR-191 as a modulator of GC function and a potential fine-tuner of FSH-driven responses.