Activation of p38 MAPK pathway by hepatitis C virus E2 in cells transiently expressing DC-SIGN.

Dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN) is a cellular receptor for hepatitis C virus for the binding of viral envelope glycoprotein E2. Interaction of DC-SIGN with the E2 may evoke cellular signal transduction implicated in viral pathogenesis. We developed a cell model with DC-SIGN transient transfection to study p38 mitogen-activated protein kinase (MAPK) signaling pathway in response to the E2 treatment. HEK293T and HeLa were DC-SIGN-deficient cell lines. DC-SIGN was detectable at the surface of HEK293T and HeLa transfected with DC-SIGN, and the levels of DC-SIGN were high in transfected-HEK293T as compared with HeLa. The transfected-HEK293T displayed ability for the E2 binding. In the transfected-HEK293T, level of p38 MAPK phosphorylation was increased upon the E2 treatment and reduced following blockage of DC-SIGN with an antibody against DC-SIGN. Phosphorylation of downstream transcription factor activating transcription factor (ATF)-2 was also up-regulated by the E2 via DC-SIGN. Similar results were obtained with NIH3T3 cells stably expressing DC-SIGN and Huh7 cells. Our results indicate that DC-SIGN transient expression in HEK293T is a useful cell model for investigating p38 MAPK pathway triggered by the E2, which may provide information for understanding cellular receptors-mediated signaling events and the viral pathogenesis.