Japanese encephalitis virus infection stimulates Src tyrosine kinase in neuron/glia.
Japanese encephalitis virus (JEV) is a neurotropic virus. The clinically manifestation of JEV-induced encephalitis is characterized by the brain inflammation and neuronal dysfunction and/or destruction. Currently, the cellular signaling molecules that underlie JEV-induced cerebral inflammation and cellular alterations are not well understood. Protein tyrosine phosphorylation events are key regulators of cellular signaling processes, including inflammation. We investigated whether Src protein tyrosine kinase (PTK) function in JEV-induced cellular changes in neuron/glia cultures. JEV infection modulated tyrosine phosphorylation events. Src PTK was hyperphosphorylated at the early stage of infection. Biochemical studies demonstrated that both inhibitors of the Src family PTK and Ras attenuated JEV-induced extracellular signal-regulated kinase (ERK) activation. Our results further revealed that PTK, Ras, and ERK inhibitors effectively suppressed JEV-induced pro-inflammatory cytokine expression and neurotoxicity. Pharmacological studies suggested that microglia secreted pro-inflammatory cytokine via Src/Ras/ERK pathway in responding to JEV infection. Another interesting observation was that nonstructural protein 3 (NS3) was able to interact with Src and showed tyrosine phosphorylation. However, the biological consequences of their interaction and exact control of NS3 tyrosine phosphorylation required further investigation. Our results suggest that the Src/Ras/ERK signaling cascade is involved in JEV-induced pro-inflammatory cytokine expression and neurotoxicity.
Raung
Shue-Ling
SL
Department of Education and Research, Taichung Veterans General Hospital, Taichung 407, Taiwan.
Chen
Shih-Yun
SY
Liao
Su-Lan
SL
Chen
Jian-Hong
JH
Chen
Chun-Jung
CJ
D000818:Animals; D002478:Cells, Cultured; D018946:Chemokine CCL5 / Q000378:metabolism; D004664:Encephalitis Virus, Japanese; D004672:Encephalitis, Japanese / Q000503:physiopathology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D009457:Neuroglia / Q000201:enzymology* / Q000821:virology; D009474:Neurons / Q000201:enzymology* / Q000821:virology; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism*
D018946:Chemokine CCL5; D053583:Interleukin-1beta; D014409:Tumor Necrosis Factor-alpha; D019061:src-Family Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D020930:MAP Kinase Kinase Kinases