ABSTRACT
Objective To explore the role of conventional protein kinase C(cPKCs) in delayed hypoxic preconditioning.Methods The biochemistry techniques of SDS-PAGE,Western bolt and Gel Doc imagine were applied to analyze the effect of repetitive hypoxic exposure(H5,H6) on the level of cPKC?,? membrane translocation and protein expression in murine brain.Results We found that cPKC? protein expression was significantly decreased(P
ABSTRACT
BACKGROUND: The protein kinase C (PKC) family consists of 3 groups of PKCs, namely the conventional PKC (cPKC), atypical PKC and novel PKC.Accumulating studies conducted in recent years have suggested that PKCs may play important roles in the development of cerebral ischemic/hypoxic preconditioning ( I / HPC ).OBJECTIVE: To observe membrane translocation of hypoxia-activated cPKC isoforms(α, βⅠ, βⅡ and γ) at cellular levels in a cell hypoxia model.DESIGN: Randomized block design.SETTING: Department of Neurobiology, College of Basic Medical Sciences,Capital University of Medical Sciences.MATERIALS: The experiment was completed at the Neurobiological Cell Culture Laboratory of Capital University of Medical Sciences in May 2004.Human neuroblastoma cells with the properties of neurons were maintained and passaged in this laboratory.METHODS: The activation of cPKC isoforms under hypoxic condition and changes of cPKCα, βⅠ, βⅡ and γ membrane translocation(an indicator of PKCs activation) in SH-SY5Y neuroblastoma cells in response to hypoxia (1% 02, 5% CO2 and 94% N2) for 0 to 24 hours were observed using SDS-PAGE, Western blotting and immunocytochemistry.MAIN OUTCOME MEASURES: Effect of sustained hypoxia on cPKC membrane translocation in human neuroblastoma cells was observed with SDS-PAGE, cPKC Western blotting, and immunocytochemistry.RESULTS: cPKCα, βⅠ and βⅡ membrane translocation were increased significantly ( P ＜ 0.05 ) in a time-dependent manner in response to hypoxic exposure, and the increase of cPKCβⅠ was more evident( P ＜ 0. 001 ) after 4hours of hypoxic exposure, whereas no cPKCγ was detected in SH-SY5Y neuroblastoma cells either under normoxic or hypoxic condition. The results suggested that all cPKC isoforms, epically cPKCβⅠ, could be activated by sustained hypoxia, and the absence of cPKCγ in SH-SY5Y neuroblastoma cells may be relevant to the loss of specific biological features of the cultured cells.CONCLUSION: Sustained hypoxia activates the isoforms of cPKCα, βⅠ and βⅡ in human neuroblastoma cells and induces their membrane translocation.cPKCγ isoform may not exist in human neuroblastoma cells, or the cells has lost certain biological characteristics.