BACKGROUND/AIMS: Ischemia/reperfusion damage to the liver remains a serious concern in many clinical situations. Major mechanisms for this certainly include oxidative stress. METHODS: The effects of ablating the p66 isoform of ShcA (p66(shc)) on hypoxia/reoxygenation (H/R)-induced oxidative stress and cell injury in hepatocytes were investigated. RESULTS: Immediately after reoxygenation, AML12 cells were clearly under oxidative stress; many cells underwent apoptosis. However, knockdown of p66(shc) by specific RNAi markedly decreased cellular oxidative stress and H/R-induced apoptosis, as well as conferring resistance to H(2)O(2) insult. These data suggest that prevention of apoptosis conferred by ablation of p66(shc) results from changed ROS-scavenging, but not inhibition of ROS generation. These data were also confirmed in fibroblasts from p66(shc) knockout mice. Anti-oxidant molecules, such as MnSOD and Ref-1 and the anti-apoptotic molecule Bcl-xL were up-regulated, and pro-apoptotic FLICE was down-regulated, by ablation of p66(shc). Interestingly, catalase expression was not affected in p66(shc)-knockdown-AML12 cells although it is a major target in other cell types. CONCLUSIONS: Our findings suggest that in hepatocytes, ablation of p66(shc) is cytoprotective against H/R-induced oxidative stress, with MnSOD and Ref-1 playing critical roles, and with up-regulation of Bcl-xL and down-regulation of FLICE contributing jointly to preventing cells from undergoing oxidant-induced apoptosis.
BACKGROUND/AIMS: Ischemia/reperfusion damage to the liver remains a serious concern in many clinical situations. Major mechanisms for this certainly include oxidative stress. METHODS: The effects of ablating the p66 isoform of ShcA (p66(shc)) on hypoxia/reoxygenation (H/R)-induced oxidative stress and cell injury in hepatocytes were investigated. RESULTS: Immediately after reoxygenation, AML12 cells were clearly under oxidative stress; many cells underwent apoptosis. However, knockdown of p66(shc) by specific RNAi markedly decreased cellular oxidative stress and H/R-induced apoptosis, as well as conferring resistance to H(2)O(2) insult. These data suggest that prevention of apoptosis conferred by ablation of p66(shc) results from changed ROS-scavenging, but not inhibition of ROS generation. These data were also confirmed in fibroblasts from p66(shc) knockout mice. Anti-oxidant molecules, such as MnSOD and Ref-1 and the anti-apoptotic molecule Bcl-xL were up-regulated, and pro-apoptotic FLICE was down-regulated, by ablation of p66(shc). Interestingly, catalase expression was not affected in p66(shc)-knockdown-AML12 cells although it is a major target in other cell types. CONCLUSIONS: Our findings suggest that in hepatocytes, ablation of p66(shc) is cytoprotective against H/R-induced oxidative stress, with MnSOD and Ref-1 playing critical roles, and with up-regulation of Bcl-xL and down-regulation of FLICE contributing jointly to preventing cells from undergoing oxidant-induced apoptosis.
Authors: Xinyu Liu; Roxanne Fernandes; Marina Gertsenstein; Alagammal Perumalsamy; Ingrid Lai; Maggie Chi; Kelle H Moley; Ellen Greenblatt; Igor Jurisica; Robert F Casper; Yu Sun; Andrea Jurisicova Journal: PLoS One Date: 2011-07-20 Impact factor: 3.240
Authors: Evgeny R Galimov; Boris V Chernyak; Alena S Sidorenko; Alesya V Tereshkova; Peter M Chumakov Journal: PLoS One Date: 2014-03-11 Impact factor: 3.240