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

Further, we detected the levels of a downstream member of the classical TGF-β/SMAD pathway, p-SMAD3, which also acts as a marker for the pathway in porcine GCs. miR-1306 mimics or miR-1306 inhibitor were transfected into GCs and the levels of p-SMAD3 in the transfected cells were analyzed. Western blot analysis showed that p-SMAD3 levels were dramatically reduced in GCs when miR-1306 was overexpressed (Figure 2A ), while p-SMAD3 levels in the GCs increased when miR-1306 was inhibited ( Figure 2B ). Next, we analyzed whether TGFBR2 mediated the modulation of the miR-1306 levels during the TGF-β/SMAD signaling pathway. As expected, we discovered that TGFBR2 overexpression rescued the miR-1306 levels by suppressing down-regulation of p-SMAD3 level induced by the miR-1306 mimics ( Figure 2C ), while knockdown of TGFBR2 inhibited the miR-1306 inhibitor-mediated enhancement in p-SMAD3 level in GCs ( Figure 2D ). These findings suggest that miR-1306 suppresses TGFBR2 to modulate the TGF-β/SMAD signaling pathway in porcine GCs. 1306 inhibitor were transfected into GCs and the levels of p-SMAD3 in the transfected cells were analyzed. Western blot analysis showed that p-SMAD3 levels were dramatically reduced in GCs when miR-1306 was overexpressed (Figure 2A ), while p-SMAD3 levels in the GCs increased when miR-1306 was inhibited ( Figure 2B ). Next, we analyzed whether TGFBR2 mediated the modulation of the miR-1306 levels during the TGF-β/SMAD signaling pathway. As expected, we discovered that TGFBR2 overexpression rescued the miR-1306 levels by suppressing down-regulation of p-SMAD3 level induced by the miR-1306 mimics ( Figure 2C ), while knockdown of TGFBR2 inhibited the miR-1306 inhibitor-mediated enhancement in p-SMAD3 level in GCs ( Figure 2D ). These findings suggest that miR-1306 suppresses TGFBR2 to modulate the TGF-β/SMAD signaling pathway in porcine GCs.