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West Nile Virus Capsid induced‐apoptosis is nitric oxide mediated and p53 dependent via mitochondrial pathways in human neuroblastoma cells
Author(s) -
Lee Sungryul,
Song Jaewhan,
Yang Joosung,
Pyo Suhkneung
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a405-b
Subject(s) - apoptosis , transfection , capsid , sh sy5y , microbiology and biotechnology , hek 293 cells , cell culture , biology , vero cell , gene knockdown , chemistry , virology , virus , biochemistry , neuroblastoma , genetics
West Nile Virus (WNV) is a neurotropic, a positive single‐stranded RNA of mosquito‐borne flavivirus. Capsid (WNV Cp) protein has been shown to induce apoptosis in human cells via mitochondrial‐based caspase‐9 pathway. However, the precise mechanisms by which capsid induces apoptosis have not been fully elucidated. SH‐Sy5Y cells were transiently transfected with EGFP‐fused cased (pEGFP‐C2‐WNV Cp) and subjected to cell staining, RT‐PCR, Western blotting, and Flow cytometric assay to investigate the mechanism(s) of apoptotic cell death by capsid protein. Here the present results demonstrate that WNV Cp induced the production of NO with concomitant activation of caspase‐2, 3 and 9, and decrease in mitochondrial membrane potential. Treatment with diphenyleneiodonium chloride (eNOS specific inhibitor) or PTIO (NO scavenger) resulted in a decrease in the WNV Cp‐induced cell cytotoxicity. Moreover, we found that WNV Cp induced up‐regulation of eNOS and HO‐1, but down‐regulated the Cox‐2 mRNA expression. However, co‐transfection of WNV Cp with Jab1 which interacts with capsid and translocates it into cytoplasm reduced the NO production and the number of apoptotic cells. We also examined the level of p53 expression because the activation of caspase‐9 is known to be an effective target of p53. Data demonstrate that treatment with WNV Cp resulted in an increase of p53 level in SH‐SY5Y cells and the ability of WNV Cp in mediating apoptosis in the SH‐SY5Y line expressing a dominant negative mutant of p53 was significantly diminished. Taken together, our data suggested that WNV Cp induces apoptosis through a mitochondrial damage‐mediated NO production pathway and this apoptosis may be regulated by association with p53.