An Xiaopeng, Song Yuxuan, Hou Jinxing, Zhang Yue, Chen Kaiwen, Ma Haidong, Zhao Xinyan, Li Guang, Gao Kexin, Wang Shan, Cao Binyun, Bai Yueyu
College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, P.R. China.
Animal Engineering Branch, Yangling Vocational & Technical College, Yangling, Shaanxi, P.R. China.
PLoS One. 2017 Jul 13;12(7):e0181162. doi: 10.1371/journal.pone.0181162. eCollection 2017.
Follicular atresia mainly results from the apoptosis of granulosa cells (GCs). Whilst our previous investigations examined the role of chi-miR-4110 in regulating ovarian function, the present study detected the role of chi-miR-4110 in GC development. We transfected caprine GCs cultured in vitro with chi-miR-4110 mimics. Results revealed that chi-miR-4110 decreased mRNA and protein levels of Smad2 by targeting its 3'-untranslated region (3'UTR). FoxC1 and Sp1 mRNA and protein levels markedly increased, whereas those of bHLHe22 significantly decreased (P<0.01 or 0.05) in GCs transfected with the chi-miR-4110 mimics. Further studies revealed a significantly higher number of apoptotic cells in GCs transfected with the chi-miR-4110 mimics (P< 0.05) than in GCs transfected with mimics negative control. GCs transfected with the chi-miR-4110 mimics exhibited significantly increased mRNA and protein levels of the pro-apoptotic gene Bax (P<0.01) and significantly decreased expression levels of the anti-apoptotic gene BCL-2 (P<0.01). Smad2 interference (Si-1282) results were consistent with those of the chi-miR-4110 mimics. Previous reports and our results showed that chi-miR-4110 increases Sp1 expression by repressing Smad2. The increase in Sp1 induces p53-upregulated modulator of apoptosis, which increases the relative abundance of Bax and causes caprine GC apoptosis. Our findings may provide relevant data for the investigation of miRNA-mediated regulation of ovarian functions.
卵泡闭锁主要由颗粒细胞（GCs）凋亡引起。虽然我们之前的研究探讨了chi-miR-4110在调节卵巢功能中的作用，但本研究检测了chi-miR-4110在GCs发育中的作用。我们用chi-miR-4110模拟物转染体外培养的山羊GCs。结果显示，chi-miR-4110通过靶向Smad2的3'-非翻译区（3'UTR）降低其mRNA和蛋白水平。在转染了chi-miR-4110模拟物的GCs中，FoxC1和Sp1的mRNA和蛋白水平显著升高，而bHLHe22的水平则显著降低（P<0.01或0.05）。进一步研究发现，转染chi-miR-4110模拟物的GCs中凋亡细胞数量显著高于转染模拟物阴性对照的GCs（P<0.05）。转染chi-miR-4110模拟物的GCs中促凋亡基因Bax的mRNA和蛋白水平显著升高（P<0.01），抗凋亡基因BCL-2的表达水平显著降低（P<0.01）。Smad2干扰（Si-1282）的结果与chi-miR-4110模拟物的结果一致。先前的报道和我们的结果表明，chi-miR-4110通过抑制Smad2来增加Sp1的表达。Sp1的增加诱导了p53上调的凋亡调节因子，从而增加了Bax的相对丰度并导致山羊GCs凋亡。我们的研究结果可能为研究miRNA介导的卵巢功能调节提供相关数据。
