PRKACA modulates endoplasmic reticulum stress-associated dysfunction in granulosa cell models relevant to polycystic ovary syndrome

Endoplasmic reticulum (ER) stress contributes to granulosa-cell dysfunction in polycystic ovary syndrome (PCOS), but relevant candidate regulators remain incompletely defined. We integrated public granulosa-lineage transcriptomic datasets with ER stress-related gene filtering, machine-learning and network analyses, single-cell RNA sequencing, assessment in primary granulosa cells, and functional studies in KGN and SVOG cells. Among 483 differentially expressed genes, 63 overlapped with ER stress-related genes, and PRKACA and GPX7 were prioritized computationally. Dataset-specific analyses revealed heterogeneous PRKACA expression across public PCOS cohorts, with none of the dataset-specific associations remaining significant after FDR correction. In our small independent clinical granulosa-cell cohort, PRKACA expression was lower in PCOS. PRKACA was therefore prioritized for functional investigation rather than interpreted as a uniformly dysregulated PCOS marker. PRKACA knockdown reduced CREB phosphorylation, CYP19A1 and BCL2 expression, while increasing GRP78, CHOP and BAX expression and apoptosis, and reducing estradiol (E2) and progesterone (P4) secretion. 4-phenylbutyric acid (4-PBA) partially attenuated these knockdown-associated changes. Conversely, PRKACA overexpression attenuated tunicamycin-induced ER stress-associated apoptosis and partially preserved CYP19A1 expression and steroid hormone secretion. These findings support a functional role for PRKACA in modulating ER stress-associated granulosa-cell homeostasis, although direct molecular regulation of the unfolded protein response remains to be established.