Liu Lian, Wang Jian-Fei, Fan Jie, Rao Yi-Song, Liu Fang, Yan You-E, Wang Hui
Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan 430071, China.
Department of Pharmacology, Medical School of Yangtze University, Jingzhou 434000, China.
Int J Mol Sci. 2016 Sep 3;17(9):1477. doi: 10.3390/ijms17091477.
Steroidogenic acute regulatory (StAR) protein plays a pivotal role in steroidogenesis. Previously, we have demonstrated that prenatal nicotine exposure suppressed fetal adrenal steroidogenesis via steroidogenic factor 1 deacetylation. This study further explored the potential role of the transcriptional repressor Yin Yang 1 (YY1) in nicotine-mediated StAR inhibition. Nicotine was subcutaneously administered (1.0 mg/kg) to pregnant rats twice per day and NCI-H295A cells were treated with nicotine. StAR and YY1 expression were analyzed by real-time PCR, immunohistochemistry, and Western blotting. Histone modifications and the interactions between the YY1 and StAR promoter were assessed using chromatin immunoprecipitation (ChIP). Prenatal nicotine exposure increased YY1 expression and suppressed StAR expression. ChIP assay showed that there was a decreasing trend for histone acetylation at the StAR promoter in fetal adrenal glands, whereas H3 acetyl-K14 at the YY1 promoter presented an increasing trend following nicotine exposure. Furthermore, in nicotine-treated NCI-H295A cells, nicotine enhanced YY1 expression and inhibited StAR expression. ChIP assay showed that histone acetylation decreased at the StAR promoter in NCI-H295A cells and that the interaction between the YY1 and StAR promoter increased. These data indicated that YY1-medicated histone deacetylation modification in StAR promoters might play an important role in the inhibitory effect of nicotine on StAR expression.
类固醇生成急性调节（StAR）蛋白在类固醇生成中起关键作用。此前，我们已经证明产前尼古丁暴露通过类固醇生成因子1去乙酰化抑制胎儿肾上腺类固醇生成。本研究进一步探讨转录抑制因子阴阳1（YY1）在尼古丁介导的StAR抑制中的潜在作用。每天两次给怀孕大鼠皮下注射尼古丁（1.0 mg/kg），并用尼古丁处理NCI-H295A细胞。通过实时PCR、免疫组织化学和蛋白质印迹分析StAR和YY1的表达。使用染色质免疫沉淀（ChIP）评估组蛋白修饰以及YY1与StAR启动子之间的相互作用。产前尼古丁暴露增加了YY1的表达并抑制了StAR的表达。ChIP分析表明，胎儿肾上腺中StAR启动子处的组蛋白乙酰化呈下降趋势，而尼古丁暴露后YY1启动子处的H3乙酰化-K14呈上升趋势。此外，在尼古丁处理的NCI-H295A细胞中，尼古丁增强了YY1的表达并抑制了StAR的表达。ChIP分析表明，NCI-H295A细胞中StAR启动子处的组蛋白乙酰化减少，并且YY1与StAR启动子之间的相互作用增加。这些数据表明，YY1介导的StAR启动子组蛋白去乙酰化修饰可能在尼古丁对StAR表达的抑制作用中起重要作用。
