ABAD enhances Abeta-induced cell stress via mitochondrial dysfunction.
Amyloid-beta peptide (Abeta) binding alcohol dehydrogenase (ABAD), an enzyme present in neuronal mitochondria, is a cofactor facilitating Abeta-induced cell stress. We hypothesized that ABAD provides a direct link between Abeta and cytotoxicity via mitochondrial oxidant stress. Neurons cultured from transgenic (Tg) mice with targeted overexpression of a mutant form of amyloid precursor protein and ABAD (Tg mAPP/ABAD) displayed spontaneous generation of hydrogen peroxide and superoxide anion, and decreased ATP, as well as subsequent release of cytochrome c from mitochondria and induction of caspase-3-like activity followed by DNA fragmentation and loss of cell viability. Generation of reactive oxygen species (ROS) was associated with dysfunction at the level of mitochondrial complex IV (cytochrome c oxidase, or COX). In neurons cultured from Tg mAPP/ABAD mice, COX activity was selectively decreased, and cyanide, an inhibitor of complex IV, exacerbated leakage of ROS, induction of caspase-3-like activity, and DNA fragmentation. In vivo, Tg mAPP/ABAD mice displayed reduced levels of brain ATP and COX activity, diminished glucose utilization, as well as electrophysiological abnormalities in hippocampal slices compared with Tg mAPP mice. In contrast, neither Tg ABAD mice nor nontransgenic (non-TG) littermates showed similar changes in ATP, COX activity, glucose utilization or electrophysiological properties. Each of the genotypes (Tg ABAD, Tg mAPP and Tg mAPP/ABAD mice, and non-TG littermates) displayed normal reproductive fitness, development and lifespan (1) These findings link ABAD-induced oxidant stress to critical aspects of Alzheimer's disease (AD)-associated cellular dysfunction, suggesting a pivotal role for this enzyme in the pathogenesis of AD.
Takuma
Kazuhiro
K
Departments of Surgery, Pathology, and Neurology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
Yao
Jun
J
Huang
Jianmin
J
Xu
Hongwei
H
Chen
Xi
X
Luddy
John
J
Trillat
Anne-Cecile
AC
Stern
David M
DM
Arancio
Ottavio
O
Yan
Shirley Shidu
SS
D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D000544:Alzheimer Disease / Q000235:genetics; D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000502:physiology; D000818:Animals; D017209:Apoptosis; D001921:Brain / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D003433:Crosses, Genetic; D053938:DNA Fragmentation; D004579:Electron Transport; D004594:Electrophysiology; D004789:Enzyme Activation; D015870:Gene Expression; D006801:Humans; D015151:Immunoblotting; D008564:Membrane Potentials; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008928:Mitochondria / Q000502:physiology* / Q000648:ultrastructure; D009154:Mutation; D009474:Neurons / Q000201:enzymology / Q000648:ultrastructure*; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000032:analysis / Q000378:metabolism
D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D017382:Reactive Oxygen Species; D000255:Adenosine Triphosphate; D015094:3-Hydroxyacyl CoA Dehydrogenases; C108634:HSD17B10 protein, human; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases