title: Enhancement of activation of caspases by presenilin 1 gene mutations and its inhibition by secretase inhibitors.
abstract: Presenilin 1 (PS1) gene mutations are the major causes of early-onset familial Alzheimer's disease. Acceleration of apoptosis is one of the major pathogenic mechanisms of PS1 mutants, and PS1 mutants have also been reported to induce overproduction of amyloid-beta protein 42. Here, we investigated aberrancy in activation of initiator caspases related to two PS1 gene mutations, I143T and G384A. Acceleration of apoptosis, elevation of caspase-3/7 activity, and significant increases in caspase-4, -8 and -9 activities during apoptosis induced by several agents were found in these mutant PS1-transfected cells. Interestingly, thapsigargin treatment enhanced caspase-4 and -9 activities in I143T-mutant PS1-transfected cells, while hydrogen peroxide treatment enhanced caspase-4, -8 and -9 activities in G384A-mutant PS1-transfected cells, indicating diverse apoptosis-promoting effects of PS1 gene mutations. In addition, treatment with a beta-secretase inhibitor or gamma-secretase inhibitor significantly attenuated the effects of the PS1 mutants on caspase-3/7 activation and recovered cell viability. Our present data suggest that these PS1 mutants accelerate the activation of initiator caspases and promote apoptosis, which may be associated, at least in part, with amyloid-beta production.
authors.affiliation: Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Katsue
authors.initials: K
authors.lastname: Miyoshi
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Ohyagi
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Sakae
authors.forename: Kyoko
authors.initials: K
authors.lastname: Motomura
authors.forename: Linqing
authors.initials: L
authors.lastname: Ma
authors.forename: Takayuki
authors.initials: T
authors.lastname: Taniwaki
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Furuya
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tabira
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kira
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism*; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors / Q000378:metabolism; D017209:Apoptosis / Q000502:physiology; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D020169:Caspases / Q000378:metabolism*; D053471:Caspases, Initiator / Q000378:metabolism; D045744:Cell Line, Tumor; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009154:Mutation; D009447:Neuroblastoma; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D016877:Oxidants / Q000494:pharmacology; D053764:Presenilin-1 / Q000235:genetics* / Q000378:metabolism*; D019284:Thapsigargin / Q000494:pharmacology; D014162:Transfection
chemical_list: D004791:Enzyme Inhibitors; D016877:Oxidants; C508853:PSEN1 protein, human; D053764:Presenilin-1; D019284:Thapsigargin; D006861:Hydrogen Peroxide; D053829:Amyloid Precursor Protein Secretases; C093516:CASP4 protein, human; D053148:Caspase 3; D053179:Caspase 7; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; D053471:Caspases, Initiator