Hepatitis C Virus (HCV) Proteins Induce NADPH Oxidase 4 Expression in a Transforming Growth Factor β-Dependent Manner: a New Contributor to HCV-Induced Oxidative Stress
Hepatitis C Virus (HCV) Proteins Induce NADPH Oxidase 4 Expression in a Transforming Growth Factor β-Dependent Manner: a New Contributor to HCV-Induced Oxidative Stress
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DOI：
10.1128/jvi.01059-09
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发表时间：
2009-12-15
影响因子：
5.4
通讯作者：
Leto, Thomas L.
中科院分区：
文献类型：
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作者：
Boudreau, Howard E.;Emerson, Suzanne U.;Leto, Thomas L.
病毒性肝炎诱导的氧化应激伴随转化生长因子β（TGF-β）水平升高和肝纤维化是丙型肝炎病毒（HCV）感染的标志。氧化还原调节机制在丙型肝炎病毒引起的肝病的发病机制还不清楚。我们目前的研究结果表明，来自Nox 4的活性氧（ROS），NADPH氧化酶（Nox）家族的成员，可能在HCV诱导的肝脏疾病中发挥作用。我们发现HCV（基因型1a）cDNA构建体（全长和亚基因组）、单独的核心蛋白、病毒RNA或复制型HCV（JFH-AM 2）的表达诱导了人肝细胞系（Huh-7、Huh-7.5、HepG 2和CHL）中Nox 4 mRNA的表达和ROS的产生。相反，表达Nox 4短发夹RNA（shRNA）或Nox 4的失活显性负性形式的肝细胞在用HCV转染细胞时显示ROS产生减少。人和鼠的Nox 4的启动子被用来证明Nox 4 mRNA的转录调控由HCV，和一个荧光素酶报告绑到一个类似的2-kb的Nox 4的启动子区确定的HCV-响应调节区域的Nox 4的表达。此外，人Nox 4启动子对TGF-β 1有反应，HCV核心依赖性Nox 4诱导可被抗TGF-β抗体或显性负性TGF-β受体II型表达阻断。这些发现确定了HCV作为Nox 4基因表达的调节剂，随后通过自分泌TGF-β依赖性机制产生ROS。总的来说，这些数据提供的证据表明，HCV诱导的Nox 4有助于ROS的产生，并可能与HCV诱导的肝脏疾病。
Viral hepatitis-induced oxidative stress accompanied by increased levels of transforming growth factor beta (TGF-beta) and hepatic fibrosis are hallmarks of hepatitis C virus (HCV) infection. The mechanisms of redox regulation in the pathogenesis of HCV-induced liver disease are not clearly understood. The results of our current studies suggest that reactive oxygen species (ROS) derived from Nox4, a member of the NADPH oxidase (Nox) family, could play a role in HCV-induced liver disease. We found that the expression of HCV (genotype 1a) cDNA constructs (full-length and subgenomic), core protein alone, viral RNA, or replicating HCV (JFH-AM2) induced Nox4 mRNA expression and ROS generation in human hepatocyte cell lines (Huh-7, Huh-7.5, HepG2, and CHL). Conversely, hepatocytes expressing Nox4 short hairpin RNA (shRNA) or an inactive dominant negative form of Nox4 showed decreased ROS production when cells were transfected with HCV. The promoters of both human and murine Nox4 were used to demonstrate transcriptional regulation of Nox4 mRNA by HCV, and a luciferase reporter tied to an similar to 2-kb promoter region of Nox4 identified HCV-responsive regulatory regions modulating the expression of Nox4. Furthermore, the human Nox4 promoter was responsive to TGF-beta 1, and the HCV core-dependent induction of Nox4 was blocked by antibody against TGF-beta or the expression of dominant negative TGF-beta receptor type II. These findings identified HCV as a regulator of Nox4 gene expression and subsequent ROS production through an autocrine TGF-beta-dependent mechanism. Collectively, these data provide evidence that HCV-induced Nox4 contributes to ROS production and may be related to HCV-induced liver disease.