张玉静,
肖芳,
钟才高
中南大学湘雅公共卫生学院, 长沙 410000
作者简介: 周晓昕(1990-),女,硕士,研究方向为肝脏毒理学,E-mail:bjzyyzxx@163.com.
基金项目: 国家自然科学基金(81172701)中图分类号: X171.5
The Effect of VDAC1 on Cr(Ⅵ)-induced Mitochondria-dependent Apoptosis in L02 Hepatocytes
Zhou Xiaoxin,Zhang Yujing,
Xiao Fang,
Zhong Caigao
Xiangya School of Public Health, Central South University, Changsha 410000, China
CLC number: X171.5
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摘要:铬(chromium)是一种在工业生产过程中广泛使用的重金属，进入人体后可导致急慢性中毒，具有神经毒性、基因毒性、致癌性和免疫毒性。了解六价铬(hexavalent chromium, Cr(Ⅵ))的细胞毒性，进一步探究Cr(Ⅵ)的毒作用机制，可为防治Cr(Ⅵ)对人群健康的损害提供实验依据。电压依赖性阴离子通道蛋白1(voltage-dependent anion channel-1, VDAC1)参与调控线粒体外膜通透性，影响细胞凋亡；同时VDAC1也是BCL-2家族的重要结合位点，它可与BAX/BAK相互作用形成孔道，使线粒体内的凋亡相关蛋白，如细胞色素C等，进入胞浆，引起细胞凋亡。但VDAC1影响细胞凋亡的确切路径与分子机制，目前尚未完全研究清楚。使用L02人正常肝细胞作为实验对象，通过慢病毒包装法建立VDAC1低表达细胞系，检测在相同浓度Cr(Ⅵ)处理的条件下，与非染毒组相比，不同受试细胞的生存率、凋亡情况、活性氧簇(reactive oxygen species, ROS)生成量、线粒体功能和凋亡诱导因子(AIF)的变化情况是否存在差异。结果表明，与VDAC1正常表达的细胞相比，VDAC1低表达组在Cr(Ⅵ)染毒的情况下，细胞生存率升高，凋亡率下降，细胞内ROS生成量减少，MPTP活性增加不明显，胞浆内细胞色素C(Cytochrome C, Cyt C)和AIF含量降低。上述研究结果表明VDAC1参与了由六价铬诱导的线粒体依赖性肝细胞凋亡，并且抑制VDAC1的表达可减轻因Cr(Ⅵ)暴露而引起的L02肝细胞损伤。
关键词: 六价铬/
电压依赖性阴离子通道/
线粒体通透性转换孔/
凋亡
Abstract:Chromium is a widely used chemical, which demonstrated the acute and chronic toxicity, including neurotoxicity, genotoxicity, carcinogenicity and immunotoxicity. We aimed to provide experimental evidence for the prevention and cure of the hexavalent chromium (Cr(Ⅵ))-induced hazard. Voltage-dependent anion channel-1 (VDAC1) is an essential player in mammalian apoptosis by regulating mitochondrial membrane permeability. VDAC1 is a key functional target of the BCL-2 protein family, and BAX and BAK can interact with VDAC1 and form a large pore, through which apoptogenic proteins such as cytochrome C released. But the molecular mechanism of VDAC1 in cell apoptosis is still not clear. We established the VDAC1 stably knocked-down cell lines L02-VDAC1-1 and shVDAC1-2 through sustained expression of shRNA against VDAC1 and then detected the survival rate, the apoptosis rate, reactive oxygen species (ROS) production, mitochondrial function and the contents of apoptosis inducing factor. The result showed that the survival rate of the shVDAC is higher than that of L02 and the apoptosis rate is decreased. The result concerning ROS production showed that knocking down of VDAC1 can prevent Cr(Ⅵ)-induced ROS accumulation compared with L02. The inner MPTP and the contents of cytochrome C (cyt C) and apoptosis inducing factors were significantly increased in response to Cr(Ⅵ) stimuli in L02, but these phenomena did not occur in shVDAC1. The results in this study demonstrated that VDAC1 mediates Cr(Ⅵ)-induced L02 hepatocytes apoptosis, and the inhibition of VDAC1 expression could reduce the adverse effects induced by Cr(Ⅵ) exposure.
Key words:Cr(Ⅵ)/
VDAC/
MPTP/
apoptosis.
