丙型肝炎病毒核心蛋白作用研究进展

丙型肝炎病毒(hepatitis C virus,HCV)是一种主要经过血液传播的肝炎病毒,是造成慢性肝炎、肝硬化甚至肝癌的主要原因之一.目前人们对HCV的致病机制的认识仍不很清楚,也缺乏针对HCV有效的治疗方法及疫苗预防.近年研究发现HCV核心(Core,C)蛋白除作为核壳体蛋白具有病毒颗粒组装功能外,还参与调节细胞凋亡、脂代谢、转录以及抗原呈递等作用,与干扰素抵抗也有密切关系.HCV C蛋白具有广泛的反式激活作用,与宿主细胞蛋白相互作用,是导致病毒持续性感染以及肝细胞癌发生的重要原因.深入认知和分析HCV C蛋白分子生物学特性,对阐明HCV持续性感染与致癌机制以及HCV对肝细胞脂肪变与干扰素疗效的影响等诸多问题具有重要意义.     

丙型肝炎病毒蛋白在转基因模型中的作用机制研究进展

丙型肝炎病毒(hepatitis C virus,HCV)与肝炎、肝硬化和肝癌的发生密切相关.由于HCV通常只在人和高级灵长类动物中形成自然感染,因此极少有研究建立HCV长期感染的实验室模型,HCV感染的病理生理学变化及其与宿主相互作用的相关研究也因此受到限制.近年来,转基因技术为研究人类疾病的分子机制提供了方法,在此基础上开展的转基因细胞系,嵌合体和转基因动物模型在感染性疾病研究中的价值已得到证实.本文综述了近年来HCV转基因模型中HCV蛋白相关的可能致病机制.     

丙型肝炎病毒编码蛋白的生物学功能

丙型肝炎是由丙型肝炎病毒(hepatitis C virus,HCV)引起的传染性疾病.是慢性肝病的主要原因之一,本文系统阐述病毒编码蛋白通过直接与细胞内重要调节分子结合,以病毒-宿主细胞相互作用方式影响细胞重要的信号通路,导致细胞增殖、分化等发生异常,干扰机体免疫防御功能,削弱宿主对HCV感染细胞的抗病毒应答,有利于慢性持续性感染的建立,最终促使HCV相关肝病的发生和发展.加强对病毒蛋白生物学功能的研究,将有助于探讨HCV致病机制和免疫逃逸机制,对HCV特异靶向药物和治疗性疫苗的研究和开发也具有重要的意义.     

丙型肝炎病毒与2型糖尿病关系的研究

0引言1989年应用分子生物学技术发现了丙型肝炎病毒(hepatitis C virus,HCV),并证实可导致肝脏慢性疾病,是输血后肝炎的主要病因.全世界有1.7亿人感染HCV,面临肝硬化和肝细胞癌的威胁.研究表明HCV感染及其所致慢性肝病与糖尿病(diabetes mellitus DM)有明显的相     

一种用于HCV核心蛋白体外表达研究的CHO细胞模型的建立

目的:建立丙型肝炎病毒(hepatitis C virus,HCV)核心(core,C)蛋白体外表达的非肝细胞模型.方法:核酸酶切法鉴定含有HCV1b基因型C蛋白编码基因的重组质粒pCMH6K的稳定性,将pCMH6K瞬时及稳定转染于中华仓鼠卵巢(China hamster ovary,CHO)细胞并连续传代110 d,...     

丙型肝炎病毒非结构蛋白NS3致肝癌机制的研究进展

大量研究显示丙型肝炎病毒(hepatitis C virus,HCV)持续感染肝细胞能导致肝细胞癌(hepatocellular carcinoma,HCC),但其致癌机制目前还不十分清楚.HCV是一种RNA病毒,其基因组不能整合到宿主染色体中引起基因突变,可能是通过其表达的蛋白质引起细胞转化.由于HCV NS3含有多种蛋白酶活性,因而推测HCV NS3在肝细胞癌的形成过程中具有重要作用,本文就HCV NS3致癌机制的研究进展作一综述.     

本刊常用英文缩写词汇

正甲型肝炎病毒(hepatitis A virus,HAV)乙型肝炎病毒(hepatitis B virus,HBV)丙型肝炎病毒(hepatitis C virus,HCV)慢性乙型肝炎(chronic hepatitis B,CHB)慢性丙型肝炎(chronic hepatitis C,CHC)肝细胞肝癌(hepatocellular carcinoma,HCC)原发性肝癌(primary hepatocellular carcinoma,PHC)人类免疫缺陷病毒(human immunodeficiency virus,HIV)     

本刊常用英文缩写词汇

正甲型肝炎病毒(hepatitis A virus,HAV)乙型肝炎病毒(hepatitis B virus,HBV)丙型肝炎病毒(hepatitis C virus,HCV)人类免疫缺陷病毒(human immunodeficiency virus,HIV)巨细胞病毒(CMV)获得性免疫缺陷综合征(AIDS)血压(BP)肝细胞癌(HCC)红细胞(RBC)白细胞(WBC)血小板(PLT)白蛋白(ALB)总蛋白(TP)血红蛋白(Hb)免疫球蛋白(Ig)甲胎蛋白(AFP)白细胞介素(IL)     

肝脏疾病与甲状腺功能状态

许多肝脏疾病会出现甲状腺功能异常,引起肝炎的乙型肝炎病毒(hepatitis B virus,HBV)和丙型肝炎病毒(hepatitis C virus,HCV)感染及肝炎本身可以出现甲状腺功能异常,抗HBV、HCV治疗的干扰素α引起甲状腺功能异常也很常见.肝硬化、非酒精性脂肪性肝病(nonalcoholic fatty liver disease,NAFLD)可以出现甲状腺功能异常,但是NAFLD与甲状腺功能异常的因果关系未阐明.同时,甲状腺疾病如甲状腺功能亢进(甲亢)、甲状腺功能减退(甲减)也可以出现肝功能异常.抗甲状腺药物(antithyroid drugs,ATD)和超常规剂量左旋甲状腺素均可导致肝损害,但以ATD更多见.     

HBV/HCV重叠感染的抗病毒治疗

从全球范围看,乙型肝炎病毒(hepatitis B virus,HBV)和丙型肝炎病毒(hepatitis C virus,HCV)重叠感染估计约有700-2000万人口感染.重叠感染和单一HBV或HCV感染比较,更易发展为肝硬化、肝细胞癌甚至肝衰竭的比例也高,HBV和HCV重叠感染可有四种不同的临床模式,即HCV活动...     

Hepatocellular carcinoma: role of hepatitis B and hepatitis C viruses proteins in hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is the most important primary hepatic cancer, being a common cancer type worldwide. Many aetiological factors have been related with HCC development, such as cirrhosis, hepatitis viruses and alcohol. Chronic infection with hepatitis B (HBV) and C viruses (HCV) often results in cirrhosis and enhances the probability of developing HCC. The underlying mechanisms that lead to malignant transformation of infected cells, however, remain unclear. HBV is a DNA virus that integrates into the host genome, and this integration is believed, in part, to be carcinogenic. Besides, the virus encodes a 17 kDa protein, HBx, which is known to be a causative agent in the formation of HCC. On the contrary, HCV is a RNA virus that does not integrate into the host genome but likely induces HCC through host protein interactions or via the inflammatory response to the virus. Products encoded in the HCV genome interfere with and disturb intracellular signal transduction. Some HCV proteins, such as the core protein, NS3 and NS5A, have seen to have a regulatory effect on cellular promoters, to interact with a number of cellular proteins, and to be involved in programmed-cell death modulation under certain conditions. The identification of these proteins functions in HCC development and the subsequent development of strategies to inhibit protein-protein interactions may be the first step towards reducing the chronicity and/or of the carcinogenicity of these two viruses.     

Association of filamin A and vimentin with hepatitis C virus proteins in infected human hepatocytes

Chronic hepatitis C (CHC) infection caused by hepatitis C virus (HCV) is a major cause of liver disease and remains a major therapeutic challenge. A variety of host proteins interact with HCV proteins. The definitive role of cytoskeletal (CS) proteins in HCV infection remains to be determined. In this study, our aim was to determine the expression profile of differentially regulated and expressed selected CS proteins and their association with HCV proteins in infected hepatocytes as possible therapeutic targets. Using proteomics, qRT-PCR, Western blot and immunofluorescence techniques, we revealed that filamin A (fila) and vimentin (vim) were prominently increased proteins in HCV-expressing human hepatoma cells compared with parental cells and in liver biopsies from patients with CHC vs controls. HCV nonstructural (NS) 3 and NS5A proteins were associated with fila, while core protein partially with fila and vim. Immunoprecipitation showed interactions among fila and NS3 and NS5A proteins. Cells treated with interferon-α showed a dose- and time-dependent decrease in CS and HCV proteins. NS proteins clustered at the perinuclear region following cytochalasin b treatment, whereas disperse cytoplasmic and perinuclear distribution was observed in the no-treatment group. This study demonstrates and signifies that changes occur in the expression of CS proteins in HCV-infected hepatocytes and, for the first time, shows the up-regulation and interaction of fila with HCV proteins. Association between CS and HCV proteins may have implications in future design of CS protein-targeted therapy for the treatment for HCV infection.     

Post-translational modifications of hepatitis C viral proteins and their biological significance

Replication of hepatitis C virus(HCV)depends on the interaction of viral proteins with various host cellular proteins and signalling pathways.Similar to cellular proteins,post-translational modifications(PTMs)of HCV proteins are essential for proper protein function and regulation,thus,directly affecting viral life cycle and the generation of infectious virus particles.Cleavage of the HCV polyprotein by cellular and viral proteases into more than 10 proteins represents an early protein modification step after translation of the HCV positivestranded RNA genome.The key modifications include the regulated intramembranous proteolytic cleavage of core protein,disulfide bond formation of core,glycosylation of HCV envelope proteins E1 and E2,methylation of nonstructural protein 3(NS3),biotinylation of NS4A,ubiquitination of NS5B and phosphorylation of core and NS5B.Other modifications like ubiquitination of core and palmitoylation of core and NS4B proteins have been reported as well.For some modifications such as phosphorylation of NS3 and NS5A and acetylation of NS3,we have limited understanding of their effects on HCV replication and pathogenesis while the impact of other modifications is far from clear.In this review,we summarize the available information on PTMs of HCV proteins and discuss their relevance to HCV replication and pathogenesis.     

Effects of HCV proteins in current HCV transgenic models

Hepatits C virus (HCV) is an enveloped virus with positive‐sense single‐stranded RNA genome that causes both acute and persistent infections associated with chronic hepatitis, cirrhosis and hepatocellular carcinoma, which needs fully functional human hepatocytes for its development. Due to the strict human tropism of HCV, only human and higher primates such as chimpanzees have been receptive to HCV infection and development, cognition about pathophysiololgy and host immune responses of HCV infection is limited by lacking of simple laboratory models of infection for a long time. During the past decade, gene transfer approaches have been helpful to the understanding of the molecular basis of human disease. Transgenic cell lines, chimeric and transgenic animal models were developed and had been demonstrated their invaluable benefits. This review focuses on the existing HCV transgenic models and summarize the relative results about probable pathophysical changes induced by HCV proteins.     

Understanding the interaction of hepatitis C virus with host DEAD-box RNA helicases

The current therapeutic regimen to combat chronic hepatitis C is not optimal due to substantial side effects and the failure of a significant proportion of patients to achieve a sustained virological response.Recently developed direct-acting antivirals targeting hepatitis C virus(HCV)enzymes reportedly increase the virologic response to therapy but may lead to a selection of drug-resistant variants.Besides directacting antivirals,another promising class of HCV drugs in development include host targeting agents that are responsible for interfering with the host factors crucia for the viral life cycle.A family of host proteins known as DEAD-box RNA helicases,characterized by nine conserved motifs,is known to play an important role in RNA metabolism.Several members of this family such as DDX3,DDX5 and DDX6 have been shown to play a role in HCV replication and this review will summarize our current knowledge on their interaction with HCV.As chronic hepatitis C is one of the leading causes of hepatocellular carcinoma,the involvement of DEADbox RNA helicases in the development of HCC will also be highlighted.Continuing research on the interaction of host DEAD-box proteins with HCV and the contribution to viral replication and pathogenesis could be the panacea for the development of novel therapeutics against HCV.     

Translation and replication of hepatitis C virus genomic RNA depends on ancient cellular proteins that control mRNA fates

Inevitably, viruses depend on host factors for their multiplication. Here, we show that hepatitis C virus (HCV) RNA translation and replication depends on Rck/p54, LSm1, and PatL1, which regulate the fate of cellular mRNAs from translation to degradation in the 5′-3′-deadenylation-dependent mRNA decay pathway. The requirement of these proteins for efficient HCV RNA translation was linked to the 5′ and 3′ untranslated regions (UTRs) of the viral genome. Furthermore, LSm1–7 complexes specifically interacted with essential cis-acting HCV RNA elements located in the UTRs. These results bridge HCV life cycle requirements and highly conserved host proteins of cellular mRNA decay. The previously described role of these proteins in the replication of 2 other positive-strand RNA viruses, the plant brome mosaic virus and the bacteriophage Qß, pinpoint a weak spot that may be exploited to generate broad-spectrum antiviral drugs.     

Gene expression profile of Huh‐7 cells expressing hepatitis C virus genotype 1b or 3a core proteins

Background: The liver disease expression in chronic hepatitis C patients is variable and may partially depend on the sequence of the infecting viral genotype. Aim: To identify some hepatitis C virus (HCV) genotype‐specific virus–host interactions potentially leading to clinically significant consequences. Methods: We compared the gene expression profile of Huh‐7 cells transiently expressing the core protein of HCV genotype 1b and 3a using microarray technology. Results: Thirty‐two genes were overexpressed in Huh‐7 transfected with the HCV genotype 1b core protein and 57 genes in cells transfected with the genotype 3a core protein. On the other hand, we found 20 genes downregulated by core 1b and 31 genes by core 3a. These included genes involved in lipid transport and metabolism, cell cycle, immune response and insulin signalling. Conclusion: The expression of HCV core proteins of different genotypes leads to a specific gene expression profile. This may account for the variable disease expression associated with HCV infection.     

Hepatitis C virus antigen in hepatocytes: immunomorphologic detection and identification.

Hepatitis C virus (HCV) antigen was detected immunohistochemically using fluorescein isothiocyanate-labeled immunoglobulin G fractions from chimpanzee and human sera strongly reactive with recombinant hepatitis C virus structural and non-structural proteins. The antigen was localized in the cytoplasm of hepatocytes in all 9 chimpanzees with acute hepatitis C, in 5 of 10 chimpanzees with chronic HCV infection, and in 11 of 12 patients with chronic hepatitis C. The specificity of the hepatocellular HCV and FITC-labeled probes for HCV was ascertained by blocking studies with paired serum samples obtained from 8 infected and uninfected chimpanzees or from 14 patients during the acute and chronic phases of HCV infection. Absorption experiments on FITC-labeled probes with selected host proteins (normal liver homogenate, plasma proteins, red blood cells) did not indicate cross reactivity of the probes with these antigens. Direct immunomorphologic evidence for the HCV specificity of hepatocellular HCV antigen deposits and the FITC-labeled polyclonal anti-HCVAg probe was established in absorption experiments using recombinant HCV nonstructural proteins. The putative HCV NS3 protein was the most prominent component of hepatocellular HCV antigen.     

Expression of paramyxovirus V proteins promotes replication and spread of hepatitis C virus in cultures of primary human fetal liver cells

Here we demonstrate that primary cultures of human fetal liver cells (HFLC) reliably support infection with laboratory strains of hepatitis C virus (HCV), although levels of virus replication vary significantly between different donor cell preparations and frequently decline in a manner suggestive of active viral clearance. To investigate possible contributions of the interferon (IFN) system to control HCV infection in HFLC, we exploited the well-characterized ability of paramyxovirus (PMV) V proteins to counteract both IFN induction and antiviral signaling. The V proteins of measles virus (MV) and parainfluenza virus 5 (PIV5) were introduced into HFLC using lentiviral vectors encoding a fluorescent reporter for visualization of HCV-infected cells. V protein-transduced HFLC supported enhanced (10 to 100-fold) levels of HCV infection relative to untransduced or control vector-transduced HFLC. Infection was assessed by measurement of virus-driven luciferase, by assays for infectious HCV and viral RNA, and by direct visualization of HCV-infected hepatocytes. Live cell imaging between 48 and 119 hours postinfection demonstrated little or no spread of infection in the absence of PMV V protein expression. In contrast, V protein-transduced HFLC showed numerous HCV infection events. V protein expression efficiently antagonized the HCV-inhibitory effects of added IFNs in HFLC. In addition, induction of the type III IFN, IL29, following acute HCV infection was inhibited in V protein-transduced cultures. Conclusion: These studies suggest that the cellular IFN response plays a significant role in limiting the spread of HCV infection in primary hepatocyte cultures. Strategies aimed at dampening this response may be key to further development of robust HCV culture systems, enabling studies of virus pathogenicity and the mechanisms by which HCV spreads in its natural host cell population.     

Hepatocellular carcinoma in patients with chronic hepatitis C virus infection in the Asia–Pacific region

Hepatocellular carcinoma (HCC) is the third-leading cause of cancer-related mortality worldwide. Although hepatitis B still remains the most common risk factor worldwide, chronic hepatitis C virus (HCV) infection is the driving force for the increased incidence of HCC especially in Western countries and Japan. In hepatitis B virus (HBV)-endemic areas, after successful vaccination programs against HBV, chronic HCV infection is now emerging as an important cause of chronic liver diseases. Unlike patients with chronic hepatitis B, those with chronic hepatitis C (CHC) develop HCC in the presence of established cirrhosis in most cases. However, a significant minority of CHC develops HCC in the absence of cirrhosis. Although HCV is a RNA virus with little potential for integrating its genetic material into host genome, various HCV proteins, including core, envelope, and nonstructural proteins, have oncogenic properties by inducing oxidative stress, disturbing cellular regulatory pathways associated with proliferation and apoptosis, and suppressing host immune responses. Overall, a combination of virus-specific, host genetic, environmental, and immune-related factors are likely to determine progression to HCC. Strategies aimed at eliminating the virus may provide opportunities for effective prevention of the development of HCC. Pegylated interferon plus ribavirin therapy appears to be effective at reducing the risk of HCC in patients who achieve sustained virologic responses. In summary, with the emerging importance of CHC, mechanisms of HCV-associated hepatocellular carcinogenesis should be clarified to provide insight into advanced therapeutic and preventive approaches, which eventually decrease the incidence and mortality of HCC.