ZBP1-driven PANoptosis in granulosa cells mediates follicular arrest in PCOS: integrated transcriptomic evidence and baicalin's therapeutic potential.

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder that impairs ovarian function and fertility in reproductive-aged women. Despite extensive research, the precise molecular mechanisms underlying granulosa cell (GC) dysfunction and follicular arrest in PCOS remain incompletely understood. In this study, we identify PANoptosis-a newly characterized inflammatory programmed cell death pathway-as a critical driver of GC pathology in PCOS. Key PANoptosis regulators, including ZBP1, RIPK3, TLR4, and ITPR1, were markedly upregulated and predominantly localized within GCs from PCOS patients. Single-cell trajectory analysis further revealed that the expression of these genes progressively escalates during GC differentiation, indicating sustained PANoptotic stress along follicular maturation. Concurrently, gene set variation analysis demonstrated significant enrichment of apoptosis, pyroptosis, and necroptosis pathways, underscoring PANoptosis as an integrated death mechanism contributing to GC failure. Molecular docking analysis identified baicalin, a bioactive flavonoid, as a potent binder of key PANoptosis effectors. To maintain physiological relevance, all functional validation experiments were carried out in primary human GC cultures supplemented with bovine follicular fluid (BFS), which preserves the native follicular microenvironment and ensures cellular viability and steroidogenic capacity; we further confirmed that baicalin's effects remained consistent under reduced BFS conditions, indicating that its activity is not an artefact of BFS components. Collectively, our findings elucidate a novel ZBP1-driven PANoptotic cascade underlying follicular arrest in PCOS. However, as the present work is exclusively based on in vitro data, we emphasize that baicalin should be viewed as a promising mechanistic lead rather than an established therapeutic agent; rigorous in vivo studies and clinical evaluation are indispensable prerequisites before any translational application can be considered. This study thus provides a solid molecular foundation for future intervention strategies, while highlighting the critical need for further validation in animal models and patients.