Activation of calpain in cultured neurons overexpressing Alzheimer amyloid precursor protein.
We have previously reported that overexpression of wild-type amyloid precursor protein (APP) in postmitotic neurons induces cleavage-dependent activation of caspase-3 both in vivo and in vitro. In this study, we investigated the mechanism underlying APP-induced caspase-3 activation using adenovirus-mediated gene transfer into postmitotic neurons derived from human embryonal carcinoma NT2 cells. Overexpression of wild-type APP significantly increased intracellular (45)Ca(2+) content prior to the activation of caspase-3 in NT2-derived neurons. Chelation of intracellular Ca(2+) markedly suppressed APP-induced activation of caspase-3. Furthermore, calpain, a Ca(2+)-dependent cysteine protease, was activated in neurons overexpressing APP as assessed by increased levels of calpain-cleaved alpha-fodrin and autolytic mu-calpain fragments. Neither calpain nor caspase-3 was activated in neurons expressing an APP mutant defective in the Abeta(1-20) domain. Calpain inhibitors almost completely suppressed APP-induced activation of neuronal caspase-3. E64d, a membrane permeable inhibitor of calpain, significantly suppressed APP-induced neuronal death. These results suggest that overexpression of wild-type APP activates calpain that mediates caspase-3 activation in postmitotic neurons.
Kuwako
Ken-ichiro
K
Division of Regulation of Macromolecular Functions, Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
Nishimura
Isao
I
Uetsuki
Taichi
T
Saido
Takaomi C
TC
Yoshikawa
Kazuaki
K
D000544:Alzheimer Disease / Q000378:metabolism* / Q000503:physiopathology; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism*; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology; D002154:Calpain / Q000037:antagonists & inhibitors / Q000378:metabolism*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D016923:Cell Death / Q000502:physiology*; D002614:Chelating Agents / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000502:physiology; D005822:Genetic Vectors; D006801:Humans; D007150:Immunohistochemistry; D007476:Ionophores / Q000494:pharmacology; D009154:Mutation / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D016564:Amyloid beta-Protein Precursor; D002614:Chelating Agents; D004791:Enzyme Inhibitors; D007476:Ionophores; C505407:CASP3 protein, human; D002154:Calpain; D053148:Caspase 3; D020169:Caspases; D002118:Calcium