Li Wenjie, Cao Fei, Li Juan, Wang Zhixin, Ren Yu, Liang Zheyong, Liu Peijun
Translational Medical Center, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China.
Department of Oncology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, P.R. China.
Mol Med Rep. 2016 Dec;14(6):5334-5342. doi: 10.3892/mmr.2016.5868. Epub 2016 Oct 20.
Simvastatin (SIM), a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, has been reported to inhibit the activity of hepatitis B virus (HBV), however, the mechanism underlying its antiviral function remains unknown. Minichromosome maintenance (MCM) 7, a component of the MCM complex, has been reported to act as an important host factor aiding virus genome replication in host cells. The present study demonstrated that downregulation of MCM7 inhibited the expression of proteins transferred by adenoviral vectors. This suggests an association between MCM7 and viral DNA expression. Thus, the current study aimed to investigate whether SIM affected MCM7 expression. Notably, the results of the present study indicated that following exposure to SIM the protein expression levels of MCM7 in HepG2.2.15, a human HBV‑transfected liver cell line, was decreased. In addition, the HBV DNA replication in the cell line was suppressed. As quantitative polymerase chain reaction experiments demonstrated that SIM did not downregulate the mRNA expression level of MCM7, the current study further investigated whether SIM affects the translation of MCM7. Western blot experiments indicated that SIM improved the activation of eukaryotic initiation factor‑2α (eIF2α), a protein synthesis initiation factor, and upregulated the upstream factors of eIF2α, protein kinase RNA‑like endoplasmic reticulum kinase, which is regulated by the liver kinase B1 (LKB1)‑AMP‑activated protein kinase (AMPK) signaling pathway. These results indicated that SIM induced HBV downregulation via an MCM‑dependent mechanism, and SIM may inhibit MCM7 expression by increasing the phosphorylation of eIF2α, which is mediated by the LKB1-AMPK signaling pathway.
辛伐他汀(SIM)是一种3-羟基-3-甲基戊二酰辅酶A还原酶抑制剂,据报道可抑制乙型肝炎病毒(HBV)的活性,然而,其抗病毒功能的潜在机制仍不清楚。微小染色体维持蛋白(MCM)7是MCM复合物的一个组成部分,据报道可作为一种重要的宿主因子,帮助病毒基因组在宿主细胞中复制。本研究表明,MCM7的下调抑制了腺病毒载体转移蛋白的表达。这表明MCM7与病毒DNA表达之间存在关联。因此,本研究旨在探讨SIM是否会影响MCM7的表达。值得注意的是,本研究结果表明,在人HBV转染的肝癌细胞系HepG2.2.15中,暴露于SIM后,MCM7的蛋白表达水平降低。此外,该细胞系中的HBV DNA复制也受到抑制。由于定量聚合酶链反应实验表明SIM不会下调MCM7的mRNA表达水平,本研究进一步探讨了SIM是否会影响MCM7的翻译。蛋白质印迹实验表明,SIM增强了真核起始因子2α(eIF2α)的激活,eIF2α是一种蛋白质合成起始因子,并上调了eIF2α的上游因子,即受肝脏激酶B1(LKB1)-AMP激活蛋白激酶(AMPK)信号通路调控的蛋白激酶RNA样内质网激酶。这些结果表明,SIM通过MCM依赖的机制诱导HBV下调,并且SIM可能通过增加由LKB1-AMPK信号通路介导的eIF2α磷酸化来抑制MCM7的表达。