Tuesday, April 15, 2008

Hepatitis C : Identification Of A Protein That Inhibits The Virus

ScienceDaily (Apr. 14, 2008) — Scientists in the Laboratoire Hépatite C of the Institut de Biologie de Lille in collaboration with INSERM Unit 602 and a laboratory at Stanford University have provided evidence of a protein, called EWI-2wint, that inhibits the hepatitis C virus at an early stage of its infective cycle. This research suggests possible new perspectives for the development of therapies to block the virus before it enters a cell.

Hepatitis C is a major public health problem that affects some 130 million people throughout the world. In France , where there are about 5000 new cases each year, it is estimated that half a million people could be affected by this disease. The causal agent is the hepatitis C virus (HCV) which targets cells in the liver called hepatocytes. HCV infection is usually chronic (60% to 80% of cases) and in the long term can lead to the development of cirrhosis and liver cancer.

Unlike the hepatitis A and B viruses, there is no vaccine to combat this virus. Furthermore, the treatments employed are only of limited efficacy (the failure rate reaches around 40%), and they involve considerable side effects. It is therefore crucial to develop new antiviral compounds to control this infection.

HCV uses at least three receptors to enter and infect a hepatocyte. One of these receptors is the CD81 protein, which has the particular characteristic of associating with numerous other proteins. It was by studying these CD81 partner proteins that the researchers identified the EWI-2wint protein, which prevents the recognition of CD81 by the hepatitis C virus and inhibits it at a very early stage in its infective cycle. This protein is present in other types of cells, which could explain why they are not infected by HCV. Discovery of the role of EWI-2wint in hepatocytes has demonstrated the complexity of the mechanisms of entry of HCV into its target cells, and opens the way to new therapeutic approaches.

Journal reference: The CD81 partner EWI-2wint inhibits hepatitis C virus entry. Vera Rocha-Perugini, Claire Montpellier, David Delgrange, Czeslaw Wychowski, François Helle, André Pillez, Hervé Drobecq, François Le Naour, Stéphanie Charrin, Shoshana Levy, Eric Rubinstein, Jean Dubuisson, Laurence Cocquerel. PLoS One. April 2, 2008.

This research was supported by the ANRS.

Adapted from materials provided by CNRS.

CNRS (2008, April 14). Hepatitis C : Identification Of A Protein That Inhibits The Virus. ScienceDaily. Retrieved April 15, 2008, from http://www.sciencedaily.com­ /releases/2008/04/080414213816.htm

The EWI-2wint protein is not present in hepatocytes (liver cells). When it comes into contact with the hepatocyte, the hepatitis C virus can thus bind to the CD81 protein, which will allow it to enter the cell and pursue its infective cycle. In other types of cells in the body, the EWI-2wint protein is present and interacts with CD81, thus preventing the hepatitis C virus from entering these cells. (Credit: Copyright CNRS 2008 Sophana Ung)


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