title: Cell-specific role for epsilon- and betaI-protein kinase C isozymes in protecting cortical neurons and astrocytes from ischemia-like injury.
abstract: Activation of epsilon protein kinase C (epsilonPKC) has been shown to protect cardiac myocytes against ischemia and reperfusion injury. However, the role of PKC in ischemic brain injury is less well defined. Western blot analysis of murine neurons and astrocytes in primary culture demonstrated epsilon- and betaIPKC expression in both cell types. Activation of epsilonPKC increased in neuronal cultures in response to the ischemia-like insult of oxygen-glucose deprivation (OGD). Isozyme-specific peptide activators or inhibitors of PKC were applied at various times before, during and after the OGD period. Neuron-astrocyte mixed cultures pretreated with a selective epsilonPKC activator peptide showed a significant reduction in neuronal injury after OGD and reperfusion, compared to cultures pretreated with control peptide. The epsilonPKC activator peptide counteracted the increased damage induced by pretreatment with the epsilonPKC-selective inhibitor peptide in relatively pure neuronal cultures subjected to OGD. Neither epsilonPKC activator nor inhibitor peptides affected injury of neurons when applied after OGD onset. In contrast, the betaIPKC-selective inhibitor peptide increased injury in astrocyte cultures exposed to OGD at all application times tested. Our data demonstrate protection of neurons by selective activation of epsilonPKC but enhanced astrocyte cell death with selective inhibition of betaIPKC. Thus PKC isozymes exhibit cell type-specific effects on ischemia-like injury.
authors.affiliation: Department of Anesthesia, School of Medicine, Stanford University, Stanford, CA 94305-5117, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Rachel
authors.initials: R
authors.lastname: Bright
authors.forename: Daria
authors.initials: D
authors.lastname: Mochly-Rosen
authors.forename: Rona G
authors.initials: RG
authors.lastname: Giffard
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000201:enzymology*; D002545:Brain Ischemia / Q000517:prevention & control*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000098:blood supply / Q000201:enzymology*; D018920:Coculture Techniques; D004195:Disease Models, Animal; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000201:enzymology*; D010101:Oxygen Consumption / Q000502:physiology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D064546:Protein Kinase C beta; D051744:Protein Kinase C-epsilon
chemical_list: D004791:Enzyme Inhibitors; D007527:Isoenzymes; C497256:Prkce protein, mouse; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051744:Protein Kinase C-epsilon