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Heat shock protein 70(HSP70) maintains Ca~(2+) homeostasis in PC12 cells,which may protect against apoptosis;however,the mechanisms of neuroprotection are unclear.Therefore,in this study,we examined Ca~(2+) levels in PC12 cells transfected with an exogenous lentiviral HSP70 gene expression construct,and we subsequently subjected the cells to ischemia-hypoxia/reoxygenation injury.HSP70 overexpression increased neuronal viability and ATPase activity,and it decreased cellular reactive oxygen species levels and intracellular Ca~(2+) concentration after hypoxia/reoxygenation.HSP70 overexpression enhanced the protein and m RNA expression levels of sarcoplasmic/endoplasmic reticulum Ca~(2+)-ATPase(SERCA),but it decreased the protein and m RNA levels of inositol 1,4,5-trisphosphate receptor(IP3R),thereby leading to decreased intracellular Ca~(2+) concentration after ischemia-hypoxia/reoxygenation.These results suggest that exogenous HSP70 protects against ischemia-hypoxia/reoxygenation injury,at least in part,by maintaining cellular Ca~(2+) homeostasis,by upregulating SERCA expression and by downregulating IP_3 R expression.
Heat shock protein 70 (HSP70) maintains Ca 2+ homeostasis in PC12 cells, which may protect against apoptosis; however, the mechanisms of neuroprotection are unclear. Beforefore, in this study, we examined Ca 2+ levels in PC12 cells transfected with an exogenous lentiviral HSP70 gene expression construct, and we followed cured of the cells to ischemia-hypoxia / reoxygenation injury. HSP70 overexpression increased neuronal viability and ATPase activity, and it decreased cellular reactive oxygen species levels and intracellular Ca ~ (2+ ) concentration after hypoxia / reoxygenation. HSP70 overexpression enhanced the protein and m RNA expression levels of sarcoplasmic / endoplasmic reticulum Ca ~ (2 +) - ATPase (SERCA), but it decreased the protein and m RNA levels of inositol 1,4,5 -sephosphate receptor (IP3R), thereby leading to decreased intracellular Ca 2+ concentration after ischemia-hypoxia / reoxygenation. Thesese results suggest that exogenous HSP70 protects against ischemia-hypoxia / reoxygenation injury, at least in part, by maintaining cellular Ca 2+ homeostasis, by upregulating SERCA expression and by downregulating IP 3 R expression.