抑制二氢乳清酸脱氢酶的表达对线粒体功能的影响

目的 探讨通过抑制二氢乳清酸脱氢酶(DHODH)的表达对线粒体功能状态的影响.方法 采用siRNA沉默技术抑制宫颈癌HeLa细胞中DHODH的表达,检测细胞增殖、细胞周期状况和线粒体相应功能指标(线粒体膜电位和活性氧自由基).结果 DHODH表达下调后细胞增殖减缓(停滞于G2/M期),加入外源性尿苷虽可激活DHODH嘧啶合成反应旁路,却并不能缓解增殖减缓.DHODH缺失降低了线粒体膜电位(MMP)并使活性氧自由基(ROS)的产量增加,线粒体DNA数量减少.结论 DHODH在形成线粒体氧化呼吸复合物中发挥了相应的重要作用,对米勒综合征形成及线粒体调节细胞活力产生了重要影响.

nhibition of Dihydroorotate dehydrogenase leads to mitochondrial dysfunction

Objective To investigate impairment of dihydro-orotate dehydrogenase (DHODH) would affect the respiratory chain (RC) function or not.Methods It was used siRNA (small interfering RNA)-mediated knockdown and observed the cell growth as well as cell cycle arrest.RC function and the mitochondria status were checked.Resuits DHODH knockdown induced cell growth retardation because of G2/M cell cycle arrest.Inconsistent with this,the cell retardation was not rescued by exogenous uridine,which should bypass the DHODH reaction for pyrimidine synthesis.DHODH depletion partially inhibited the RC complex Ⅲ,decreased the mitochondrial membrane poten tial,and increased the generation of ROS (reactive oxygen species).Besides,mtDNA amount decreased as well.Conclusion DHODH play a role in mitochondria respiratory chain.Considering that pyrimidine deficiency alone does not induce craniofacial dysmorphism,the DHODH mutations may contribute to the Miller syndrome in part through somehow altered mitochondrial function.