TY - JOUR
T1 - Overexpression of interferon-γ-inducible GTPase inhibits coxsackievirus B3-induced apoptosis through the activation of the phosphatidylinositol 3-kinase/Akt pathway and inhibition of viral replication
AU - Zhang, Huifang M.
AU - Yuan, Ji
AU - Cheung, Paul
AU - Luo, Honglin
AU - Yanagawa, Bobby
AU - Chau, David
AU - Stephan-Tozy, Najwan
AU - Wong, Brian W.
AU - Zhang, Jingchun
AU - Wilson, Janet E.
AU - McManus, Bruce M.
AU - Yang, Decheng
PY - 2003/8/29
Y1 - 2003/8/29
N2 - Our previous studies using differential mRNA display have shown that interferon-γ-inducible GTPase (IGTP), was up-regulated in coxsackievirus B3 (CVB3)-infected mouse hearts. In order to explore the effect of IGTP expression on CVB3-induced pathogenesis, we have established a doxycycline-inducible Tet-On HeLa cell line overexpressing IGTP and have analyzed activation of several signaling molecules that are involved in cell survival and death pathways. We found that following IGTP overexpression, protein kinase B/Akt was strongly activated through phosphorylation, which leads to phosphorylation of glycogen synthase kinase-3 (GSK-3). Furthermore, in the presence of CVB3 infection, the intensity of the phosphorylation of Akt was further enhanced and associated with a delayed activation of caspase-9 and caspase-3. These data indicate that IGTP expression appears to confer cell survival in CVB3-infected cells, which was confirmed by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl) -2H-tetrazolium salt cell viability assay. However, the ability of IGTP to induce phosphorylation of Akt and to promote cell survival was attenuated by the phosphotidylinositol-3 kinase (PI3-K) inhibitor LY294002. Transient transfection of the cells with a dominant negative Akt construct followed by doxycycline induction and CVB3 infection reversed Akt phosphorylation to basal levels and returned caspase-3 activity to levels similar to those when the PI3-K inhibitor LY294002 was added. Moreover, IGTP expression inhibited viral replication and delayed CVB3-induced cleavage of eukaryotic translation initiation factor 4G, indicating that IGTP-mediated cell survival relies on not only the activation of PI3-K/Akt, inactivation of GSK-3 and suppression of caspase-9 and caspase-3 but also the inhibition of viral replication.
AB - Our previous studies using differential mRNA display have shown that interferon-γ-inducible GTPase (IGTP), was up-regulated in coxsackievirus B3 (CVB3)-infected mouse hearts. In order to explore the effect of IGTP expression on CVB3-induced pathogenesis, we have established a doxycycline-inducible Tet-On HeLa cell line overexpressing IGTP and have analyzed activation of several signaling molecules that are involved in cell survival and death pathways. We found that following IGTP overexpression, protein kinase B/Akt was strongly activated through phosphorylation, which leads to phosphorylation of glycogen synthase kinase-3 (GSK-3). Furthermore, in the presence of CVB3 infection, the intensity of the phosphorylation of Akt was further enhanced and associated with a delayed activation of caspase-9 and caspase-3. These data indicate that IGTP expression appears to confer cell survival in CVB3-infected cells, which was confirmed by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl) -2H-tetrazolium salt cell viability assay. However, the ability of IGTP to induce phosphorylation of Akt and to promote cell survival was attenuated by the phosphotidylinositol-3 kinase (PI3-K) inhibitor LY294002. Transient transfection of the cells with a dominant negative Akt construct followed by doxycycline induction and CVB3 infection reversed Akt phosphorylation to basal levels and returned caspase-3 activity to levels similar to those when the PI3-K inhibitor LY294002 was added. Moreover, IGTP expression inhibited viral replication and delayed CVB3-induced cleavage of eukaryotic translation initiation factor 4G, indicating that IGTP-mediated cell survival relies on not only the activation of PI3-K/Akt, inactivation of GSK-3 and suppression of caspase-9 and caspase-3 but also the inhibition of viral replication.
UR - http://www.scopus.com/inward/record.url?scp=0041355437&partnerID=8YFLogxK
U2 - 10.1074/jbc.M305352200
DO - 10.1074/jbc.M305352200
M3 - Article
C2 - 12819192
AN - SCOPUS:0041355437
SN - 0021-9258
VL - 278
SP - 33011
EP - 33019
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 35
ER -