Mitigating PCOS progression: The protective effect of C-phycocyanin on ovarian granulosa cell pyroptosis via the NRF2/NLRP3/GSDMD pathway.

BACKGROUND: Pyroptosis is a proinflammatory cell death process that contributes to inflammatory diseases. C-Phycocyanin (C-PC) is a water-soluble protein pigment primarily derived from cyanobacteria, and it exhibits anti-inflammatory effects. However, the role of natural C-PC in pyroptosis in human ovarian granulosa cells (GCs), particularly in conditions like polycystic ovary syndrome (PCOS), remains unclear. This study investigates the effects of C-PC on pyroptosis and its relevance to PCOS.

METHODS: Here dehydroepiandrosterone (DHEA) was used to induce PCOS in a mouse model that was characterized by an irregular oestrous cycle, cystic follicles and an elevated serum hormone level. DHEA treatment was used to induce GC pyroptosis. Scanning electron microscopy (SEM) was used to determine cell morphology. The expression levels of key proteins for oxidative stress and pyroptosis, including nuclear factor erythroid 2-related factor 2 (NRF2), NLR family of pyrroline-containing structural domain 3 (NLRP3) inflammasomes, cleaved caspase-1, and N-GSDMD were investigated in vivo and in vitro by Western blotting and immunofluorescence staining.

RESULTS: C-PC restored the estrous cycle in PCOS mice, reduced testosterone levels, and decreased cystic follicles. It attenuated PCOS progression by reducing oxidative stress level and suppressing GCs pyroptosis. At the cellular level, C-PC inhibited DHEA-induced GC pyroptosis by blocking NLRP3 inflammasome activation and lowering ROS, effects reversed by the NRF2 inhibitor (ML385). Molecular docking analysis and CETSA suggested that C-PC may protect against PCOS by activating the NRF2 pathway or by indirectly binding to the Ser27 site of GSDMD. In addition, C-PC suppressed ROS/p38-MAPK activation induced by DHEA, and p38-MAPK agonists diminished its effect on NLRP3 inflammasome activity and GC pyroptosis protection.

CONCLUSION: C-PC exerts a protective effect on GC pyroptosis through the NRF2/NLRP3/GSDMD and ROS/p-38 MAPK pathways, highlighting its potential to mitigate inflammation and its relevance to reproductive health issues like PCOS.