miR-1306 Mediates the Feedback Regulation of the TGF-ß/SMAD Signaling Pathway in Granulosa Cells

Yang, Liu; Du, Xing; Liu, Lu; Cao, Qiuyu; Pan, Zengxiang; Li, Qifa

Based on the KEGG analysis results revealing that miR-1306 may participate in apoptosis, we further investigated its role in apoptosis in porcine GCs. FACS assay showed that overexpression of miR-1306 significantly improved the GC apoptosis rate (Figure 3A) , while a decrease in miR-1306 levels reduced it ( Figure 3B ). This suggests that miR-1306 can promote apoptosis of porcine GCs. Further, studies have shown that GC apoptosis is associated with follicular atresia. Therefore, miR-1306 level in follicles during follicular atresia of porcine ovary was measured. We discovered that the expression level of miR-1306 was remarkably increased during follicular atresia (Supplementary Figure S5) . Our data shows that GC apoptosis and follicular atresia were regulated by miR-1306 in porcine ovary, both in vitro and in vivo. Both miR-1306 mimics and TGFBR2-siRNA were co-transfected into porcine GCs to determine whether TGFBR2 mediates miR-1306-induced GC apoptosis or not. Our findings suggest that silencing of TGFBR2 could improve GC apoptosis caused by miR-1306 ( Figure 3C ). Furthermore, we co-transfected the GCs with miR-1306 inhibitor and pcDNA3.1-TGFBR2 and found that overexpression of TGFBR2 decreased the GC apoptosis rate ( Figure 3D ). Our findings show that GC apoptosis was regulated by miR-1306 in pigs by targeting TGFBR2.