title: Calpain activation and alpha-spectrin cleavage in rat brain by ethanol.
abstract: Calpain, a calcium-activated cysteine protease, has been implicated in neuronal degeneration and death. In this study, we have characterized calpain activation in adult rat cerebral cortex and cerebellum, using an experimental paradigm of in vivo chronic ethanol exposure. Ethanol treatment increased the calpain activity in cortex and cerebellum, but to a higher extent in the cortex. Western blot analysis revealed a significant decrease in m-calpain levels while calpastatin levels were unaltered. Calpain activation was further monitored by the proteolysis of alpha-spectrin (fodrin) and protein kinase C-alpha (PKC-alpha). Protease specific spectrin breakdown products revealed calpain generated 150- and 145-kDa fragments. In addition, we also observed a 120-kDa fragment characteristic of caspase-3 activation in the cerebellum. PKC-alpha levels were decreased in the cortex and cerebellum by ethanol. Calpain activation, cleavage of alpha-spectrin into calpain specific signature fragments and decreased PKC-alpha protein levels after ethanol treatment provide the evidence of calpain involvement besides caspase-3-mediated cell death in the cortex and cerebellum. Given the role of calpains in cell death, increased calpain activity followed by alpha-spectrin cleavage in this study suggests that calpains are important effectors in ethanol-mediated cell injury and alcoholic neurodegeneration.
authors.affiliation: School of Life Sciences, University of Hyderabad, India.
authors.forename: Yadavalli
authors.initials: Y
authors.lastname: Rajgopal
authors.forename: Mohan C
authors.initials: MC
authors.lastname: Vemuri
mesh_terms: D020268:Alcohol-Induced Disorders, Nervous System / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D002135:Calcium-Binding Proteins / Q000187:drug effects / Q000378:metabolism; D002154:Calpain / Q000187:drug effects* / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000187:drug effects / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D000431:Ethanol / Q000494:pharmacology*; D007527:Isoenzymes / Q000187:drug effects / Q000378:metabolism; D009410:Nerve Degeneration / Q000139:chemically induced* / Q000378:metabolism / Q000503:physiopathology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D010446:Peptide Fragments / Q000187:drug effects / Q000378:metabolism; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism; D051571:Protein Kinase C-alpha; D051381:Rats; D013049:Spectrin / Q000187:drug effects* / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
chemical_list: D002135:Calcium-Binding Proteins; D007527:Isoenzymes; D010446:Peptide Fragments; D013049:Spectrin; D000431:Ethanol; C033668:calpastatin; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D002154:Calpain; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases