Effects of Mitogen-Activated Protein Kinase Inhibitors on Tumor Necrosis Factor-α Gene Expression and Apoptosis Induction in Cultured Human Fetal Membrane Chorion Cells Infected with Influenza Virus

Abstract

Objectives: We investigated the involvement of p38 mitogen-activated protein (MAP) kinase in tumor necrosis factor (TNF)-α gene expression, apoptosis induction and virus replication in cultured human fetal membrane chorion cells infected with influenza virus. Methods: Influenza virus-infected chorion cells were incubated in the absence or presence of inhibitors of p38 MAP kinase, SB203580 and SB202190. TNF-α mRNA and hemagglutinin viral RNA (HA vRNA) were amplified with reverse transcriptase-polymerase chain reaction techniques. TNF-α protein concentrations were determined by enzyme-liked immunosorbent assay. The extent of apoptosis induction was estimated by DNA agarose gel electrophoresis. Pyrrolidine dithiocarbamate (PDTC) and ribavirin, which have been shown to inhibit apoptosis induction via the inhibition of viral gene replication, were used as positive control reagents. Results: PDTC and ribavirin inhibited the accumulation of TNF-α mRNA and HA vRNA in the virus-infected chorion cells, resulting in the suppression of TNF-α protein secretion. Both SB203580 and SB202190 suppressed TNF-α protein secretion, but not the accumulation of TNF-α mRNA as well as HA vRNA and the induction of apoptosis. Conclusions: These results suggest that p38 MAP kinase pathway is critical in TNF-α gene expression at a post-transcriptional level but not in the apoptosis induction and influenza virus replication in cultured chorion cells.