Hepatitis C virus proteins

Serine protease inhibitors as anti-hepatitis C virus agents

Approximately 3% of the worldwide population (i.e., more than 170 million people) are chronically infected with the hepatitis C virus (HCV). An estimated 20% of these patients will develop liver cirrhosis within a mean of 20 years, and 2-5% of cirrhotic patients will die of end-stage liver disease or hepatocellular carcinoma. The currently approved antiviral therapy with pegylated interferon (pegIFN) and ribavirin induces a sustained virological response (SVR) in 40-50% of patients infected with genotype 1, the most prevalent HCV type. In this review, we focus on the development and clinical application of serine protease inhibitors as anti-HCV agents. Although highly active in inducing a significant decline of serum HCV RNA, the rapid development of resistance must be counteracted in combination with other antiviral agents, currently pegIFN-alpha and ribavirin. Two serine protease inhibitors have reached clinical Phase III trials, increasing SVR rates and shortening treatment duration when combined with pegIFN and ribavirin. Trials of interferon-free targeted combination therapies are currently underway.

Hepatitis C virus: the growing challenge

BACKGROUND

Hepatitis C virus (HCV) is a major cause of liver disease worldwide. In industrialized countries, intravenous drug users (IDUs) are the main reservoir of infection. Relatively little information is available on HCV in the developing world.

SOURCES OF DATA

Peer reviewed publications and presentations at major academic meetings.

AREAS OF AGREEMENT

HCV-related cirrhosis and death from hepatocellular carcinoma are likely to rise dramatically in the next three decades. Urgent intervention is required both to minimize the burden of disease in those already infected and to reduce the incidence of new infections, particularly in the IDU population.

AREAS OF CONTROVERSY

Current models of care and commissioning in the UK and other countries do not adequately identify or treat HCV infection in IDUs. Most strategies focus on disease prevention and do not target new infections.

GROWING POINTS

New models of care are currently being developed and validated.

AREAS TIMELY FOR DEVELOPING RESEARCH

The development of new models of HCV replication will transform our understanding and capacity to treat HCV infection.

Human oncogenic viruses: hepatitis B and hepatitis C viruses and their role in hepatocarcinogenesis

Chronic infections caused by hepatitis B virus (HBV) and/or hepatitis C virus (HCV) are the main risk factors for the development of hepatocellular carcinoma (HCC) in humans. Both viruses cause a wide spectrum of clinical manifestations ranging from healthy carrier state to acute and chronic hepatitis, liver cirrhosis, and HCC. HBV and HCV belong to different viral families (Hepadnoviridae and Flaviviridae, respectively); they are characterized by different genetic structures. Clinical manifestations of these viral infections result from the interaction between these viruses and host hepatocytes (i.e. between viral and cell genomes). Proteins encoded by both viruses play an important role in processes responsible for immortalization and transformation of these cells. Chronic inflammation determined by host immune response to the viral infection, hepatocyte death and their compensatory proliferation, as well as modulation of expression of some regulatory proteins of the cell (growth factors, cytokines, etc.) are the processes that play the major role in liver cancer induced by HBV and HCV.

Mouse models for the study of HCV infection and virus-host interactions

Hepatitis C virus (HCV) is a major cause of chronic liver disease including steatosis, cirrhosis and hepatocellular carcinoma. The development of transgenic mice expressing HCV proteins and the successful repopulation of SCID/Alb-uPA mice with human hepatocytes provides an important tool for unraveling virus-host interactions in vivo. Several of these mouse models exhibit aspects of HCV-related liver disease. Thus, these in vivo models play an important role to further understand the pathogenesis of HCV infection and to evaluate the pre-clinical safety and efficacy of new antiviral compounds against HCV. This review summarizes the most important mouse models currently used to study HCV pathogenesis and infection. Finally, the perspective of these models for future HCV research as well as the design of novel small animal models is discussed.

NS5ATP9, a gene up-regulated by HCV NS5A protein

Non-structural protein 5A (NS5A) appears to interact with a variety of cellular proteins and play an important role in mediating cell growth, cellular signaling pathways and pathogenesis of hepatitis C virus (HCV). NS5ATP9 was identified as a NS5A trans-activated protein in suppression subtractive hybridization (SSH), and the regulation was confirmed by luciferase reporter assay and quantitative real time PCR (qRT-PCR). A minimal promoter region contained within the 211bp (nucleotides -161 to +50bp) immediately upstream of the transcription initiation site. NS5ATP9 is a NS5A up-regulation gene which may play a role in the pathogenesis of HCV-associated hepatocellular carcinoma.

Oral diseases associated with hepatitis C virus infection. Part 1. sialadenitis and salivary glands lymphoma

Morbidity associated with hepatitis C virus (HCV) infection is due not only to the sequelae of chronic liver disease, but also to a variety of extraheaptic manifestations (EHM). Some of the most frequently reported EHM of HCV infection involves the oral region predominantly or exclusively and they are the topics of this 2-part review. The current part 1 discusses the evidences on the association of salivary glands disorders with HCV. HCV- infected patients may frequently have histological signs of Sjögren-like sialadenitis with mild or even absent clinical symptoms. However, the pathogenetic role of HCV in Sjogren Syndrome (SS) development and the characteristics distinguishing classic SS from HCV-related sialadenitis are still an issue. It is unclear if the virus may cause a disease mimicking primary SS or if HCV is directly responsible for the development of SS in a specific subset of patients. Notably, some patients may present a triple association between HCV, SS-like sialadenitis and salivary gland lymphoma and the virus may be involved in the lymphomagenesis. The risk of having a salivary gland lymphoma is particularly high in patients with mixed cryoglobulinemia. Little attention has been paid to the effects of anti-HCV treatment on sialadenitis or lymphoma development.