Cathepsin B Regulates Mice Granulosa Cells' Apoptosis and Proliferation In Vitro.

Cathepsin B (), a lysosomal cysteine protease's high expression and activity, has been reported to cause poor-quality embryos in porcine and bovine. Nevertheless, functions in mice granulosa cells remain to explore. To discuss the functional role in follicular dynamics, we studied apoptosis, proliferation, cell cycle progression, and related signaling pathways in primary mouse granulosa cells transfected with small interference RNA specific to (siCTSB) for 48 h. Further, mRNA and protein expression of cell proliferation regulators ( and ), apoptosis regulators (, , , and ), steroidogenesis-related genes ( and ), and autophagy markers ( and ) were investigated. In addition, the effect of on steroidogenesis and autophagy was also examined. Flow cytometry analysis assay displayed that silencing of decreased the early and total apoptosis rate by downregulating , , and , and upregulating . By regulating and expression and activating the p-Akt and p-ERK pathways, knockdown increased GC proliferation and number. A significant decline in estradiol and progesterone concentrations was observed parallel to a significant decrease in autophagy-related markers and compared to the control group. Herein, we demonstrated that serves as a proapoptotic agent and plays a critical role in folliculogenesis in female mice by mediating apoptosis, autophagy, proliferation, and steroidogenesis. Hence, could be a potential prognostic agent for female infertility.