Nonstructural 3 protein of hepatitis C virus triggers an oxidative burst in human monocytes via activation of NADPH oxidase.
It has been shown that oxidative stress occurs in chronic hepatitis C. Release of reactive oxygen species (ROS) from sequestered phagocytes and activated resident macrophages represents the predominant component of oxidative stress in the liver. However, little is known about the ability of the monocyte to produce ROS in response to protein of hepatitis C virus. In this study, we investigated the ROS production in human monocytes stimulated by several viral proteins of hepatitis C virus. Human monocytes from healthy blood donors were incubated with recombinant viral protein: Core, NS3, NS4, and NS5. ROS production was measured by chemiluminescence. Only NS3 triggered ROS production in human monocytes. Generated ROS were mainly the anion superoxide. NS3 also induced a rapid and transient increase in intracellular calcium concentration measured by a video digital microscopy technique. By using different metabolic inhibitors, we showed that ROS production requires calcium influx, tyrosine kinases, and the stress-activated protein kinase, p38. The study of p47(PHOX) phosphorylation and translocation showed that NADPH oxidase was activated and involved in ROS production induced by NS3. In a second experiment, NS3 inhibited the oxidative burst induced by phorbol 12-myristate 13-acetate. These results indicate that NS3 activates NADPH oxidase and modulates ROS production, which may be involved in the natural history of hepatitis C infection.
Bureau
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Université Paul Sabatier, UPRES EA 2405, Macrophages, Médiateurs de l'Inflammation et Interactions Cellulaires, Institut Louis Bugnard INSERM IFR31, CHU Rangueil, 31403 Toulouse Cedex 04, France.
Bernad
J
J
Chaouche
N
N
Orfila
C
C
Béraud
M
M
Gonindard
C
C
Alric
L
L
Vinel
J P
JP
Pipy
B
B
D002118:Calcium / Q000378:metabolism; D004789:Enzyme Activation; D016174:Hepacivirus / Q000502:physiology*; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism* / Q000821:virology; D019255:NADPH Oxidases / Q000378:metabolism*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D017382:Reactive Oxygen Species; D016897:Respiratory Burst; D017361:Viral Nonstructural Proteins / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases
D017382:Reactive Oxygen Species; D017361:Viral Nonstructural Proteins; D019255:NADPH Oxidases; D011505:Protein-Tyrosine Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D002118:Calcium