Proteomic analysis of healthy and atretic porcine follicular granulosa cells.

Follicular atresia is initiated with the apoptosis of granulosa cells (GCs) after birth in mammals. The molecular mechanisms underlying GC apoptosis during follicular selection are unclear at present. The objective of this study is to identify the proteins and pathways that may be involved in porcine follicular atresia. Proteins isolated from GCs collected from healthy and atretic follicles were detected by tandem mass tag (TMT) protein labeling and LC-MS/MS. A total of 4591 proteins in the healthy follicle granulosa cell (HFGC) and atretic follicle granulosa cell (AFGC) groups were identified, and 399 differentially abundant proteins were found between the HFGC and AFGC groups; of which 262 proteins were significantly up-regulated and 137 proteins were significantly down-regulated. Differential protein enrichment analysis showed that proteins involved in proteolysis, protein destabilization, phagocytosis, and engulfment were more abundant in the AFGC group. Also, these proteins were mainly involved in the lysosome, phagosome, autophagy, and apoptosis pathways. Specially, PTGFRN is potential important regulated protein in the development of the antral follicle, and down-regulation of PTGFRN in GCs may lead to follicular atresia. Our study shows that the identified proteins and their related signaling pathways may play crucial roles during health follicle develop to atretic follicle. SIGNIFICANCE: Follicular atresia during 'selection' reduces the reproductive potential of sows. In this study, we found 399 proteins differentially abundant. between the HFGC and AFGC groups. These results establish a foundation for elucidating the mechanism of follicular atresia in swine.