Regulation of p38 mitogen-activated protein kinase pathway by West Nile virus in human neuroblastoma cells / 第二军医大学学报

ABSTRACT

Objective: To explore the regulation of p38 mitogen-activated protein kinase (MAPK) pathway by West Nile virus (WNV) in human neuroblastoma SH-SY5Y cells and the contributions of p38 MAPK to WNV replication as well as stress and inflammatory response related molecule expression. Methods: Total and phosphorylated p38 MAPK levels were analyzed in SH-SY5Y cells incubated with WNV for short (5, 15, 30 and 60 min) and long (12, 24, 48 and 60 h) durations by Western blotting. Dynamic changes of CCAAT/enhancer-binding protein homologous protein (CHOP), interleukin 6 (IL-6), activating transcription factor 6α (ATF6α) and interferon-stimulated gene 15 (ISG15) mRNA expression in WNV infected cells were detected by qRT-PCR. In response to WNV infection, WNV RNA level and CHOP, IL-6, ATF6α and ISG15 mRNA levels were assessed in SH-SY5Y cells transfected with p38 MAPK siRNA. Results: Incubation with WNV for short durations enhanced p38 MAPK phosphorylation compared to the untreated control. The p38 MAPK signaling pathway was activated at 12 h and 24 h in WNV-infected SH-SY5Y cells, but down-regulated at 48 h and 60 h. WNV infection led to increased mRNA expression of CHOP, IL-6 and ISG15 and reduced ATF6α mRNA. In comparison with control siRNA transfection, the levels of WNV RNA (P<0.05) and ATF6α mRNA (P<0.01) were increased and CHOP mRNA level was decreased (P<0.05) in WNV-infected SH-SY5Y cells with the p38 MAPK siRNA transfection. Conclusion: The p38 MAPK pathway is activated during early stage of WNV infection and such activation may negatively regulate WNV replication. WNV-induced stress response molecules CHOP and ATF6α and proinflammatory cytokine IL-6 production by SH-SY5Y cells are coupled with the regulation of p38 MAPK pathway.