Zhang Guo-Min, Deng Ming-Tian, Lei Zhi-Hai, Wan Yong-Jie, Nie Hai-Tao, Wang Zi-Yu, Fan Yi-Xuan, Wang Feng, Zhang Yan-Li
College of Veterinary MedicineNanjing Agricultural University, Nanjing, China.
Jiangsu Livestock Embryo Engineering LaboratoryNanjing Agricultural University, Nanjing, China.
Reproduction. 2017 Aug;154(2):111-122. doi: 10.1530/REP-16-0583.
During goat follicular development, abnormal expression of nuclear respiratory factor 1 () in granulosa cells may drive follicular atresia with unknown regulatory mechanisms. In this study, we investigated the effects of on steroidogenesis and cell apoptosis by overexpressing or silencing it in goat luteinized granulosa cells (LGCs). Results showed that knockdown of expression significantly inhibited the expression of and , which are involved in sex steroid hormones synthesis, and led to lower estrogen levels. Knockdown of resulted in an increased percentage of apoptosis, probably due to the release of cytochrome c from mitochondria, accompanied by upregulating mRNA and protein levels of apoptosis-related markers BAX, caspase 3 and caspase 9. These data indicate that might be related with steroidogenesis and cell apoptosis. Furthermore, silence reduced mitochondrial transcription factor A () transcription activity, mtDNA copy number and ATP level. Simultaneously, knockdown of suppressed the transcription and translation levels of SOD, GPx and CAT, decreased glutathione level and increased 8-OHdG level. However, the overexpression of in LGCs or gain of in silenced LGCs increased the expression of genes involved in mitochondrial function and biogenesis, and elevated the antioxidant stress system and steroids synthesis. Taken together, aberrant expression of could induce mitochondrial dysfunction and disturb the cellular redox balance, which lead to disturbance of steroid hormone synthesis, and trigger LGC apoptosis through the mitochondria-dependent pathway. These findings will be helpful for understanding the role of in goat ovarian follicular development and atresia.
在山羊卵泡发育过程中，颗粒细胞中核呼吸因子1（）的异常表达可能会驱动卵泡闭锁，但其调控机制尚不清楚。在本研究中，我们通过在山羊黄体化颗粒细胞（LGCs）中过表达或沉默核呼吸因子1，研究了其对类固醇生成和细胞凋亡的影响。结果表明，敲低核呼吸因子1的表达显著抑制了参与性甾体激素合成的和的表达，并导致雌激素水平降低。敲低核呼吸因子1导致细胞凋亡百分比增加，这可能是由于细胞色素c从线粒体释放所致，同时伴随着凋亡相关标志物BAX、半胱天冬酶3和半胱天冬酶9的mRNA和蛋白水平上调。这些数据表明核呼吸因子1可能与类固醇生成和细胞凋亡有关。此外，沉默核呼吸因子1降低了线粒体转录因子A（）的转录活性、线粒体DNA拷贝数和ATP水平。同时，敲低核呼吸因子1抑制了超氧化物歧化酶、谷胱甘肽过氧化物酶和过氧化氢酶的转录和翻译水平，降低了谷胱甘肽水平，增加了8-羟基脱氧鸟苷水平。然而，在LGCs中过表达核呼吸因子1或在沉默核呼吸因子1的LGCs中恢复核呼吸因子1的表达，增加了参与线粒体功能和生物发生的基因的表达，并提高了抗氧化应激系统和类固醇合成。综上所述，核呼吸因子1的异常表达可诱导线粒体功能障碍，扰乱细胞氧化还原平衡，导致类固醇激素合成紊乱，并通过线粒体依赖途径触发LGC凋亡。这些发现将有助于理解核呼吸因子1在山羊卵巢卵泡发育和闭锁中的作用。
