Aldehyde dehydrogenase-2 transgene ameliorates chronic alcohol ingestion-induced apoptosis in cerebral cortex.
Chronic intake of alcohol results in multiple organ damage including brain. This study was designed to examine the impact of facilitated acetaldehyde breakdown via transgenic overexpression of mitochondrial aldehyde dehydrogenase-2 (ALDH2) on alcohol-induced cerebral cortical injury. ALDH2 transgenic mice were produced using the chicken beta-actin promoter. Wild-type FVB and ALDH2 mice were placed on a 4% alcohol or control diet for 12 weeks. Protein damage and apoptosis were evaluated with carbonyl formation, caspase and TUNEL assays. Western blot was performed to examine expression (or its activation) of ALDH2, the pro- and anti-apoptotic proteins caspase-8, Bax, Bcl-2, Omi/HtrA2, apoptosis repressor with caspase recruitment domain (ARC), FLICE-like inhibitory protein (FLIP), X-linked inhibitor of apoptosis protein (XIAP), Akt, glycogen synthase kinase-3beta (GSK-3beta), p38, c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK). Chronic alcohol intake led to elevated apoptosis in the absence of overt protein damage, the effect of which was ablated by the overexpression of ALDH2 transgene. Consistently, ALDH2 transgene significantly attenuated alcohol-induced upregulation of Bax, Omi/HtrA2 and XIAP as well as downregulation of Bcl-2 and ARC without affecting alcohol-induced increase of FLIP in cerebral cortex. Phosphorylation of Akt and GSK-3beta was dampened while total/phosphorylated JNK and p38 phosphorylation were elevated following chronic alcohol intake, the effects of which were abrogated by ALDH2 transgene. Expression of total Akt, GSK-3beta, p38 and ERK (total or phosphorylated) was not affected by either chronic alcohol intake or ALDH2 transgene. Our results suggested that transgenic overexpression of ALDH2 rescues chronic alcoholism-elicited cerebral injury possibly via a mechanism associated with Akt, GSK-3beta, p38 and JNK signaling.
Center for Cardiovascular Research and Alternative Medicine, University of Wyoming, School of Pharmacy, Laramie, WY 82071, USA. jren@uwyo.edu
Jun
J
Ren
Sara A
SA
Babcock
Qun
Q
Li
Anna F
AF
Huff
Shi-Yan
SY
Li
Thomas A
TA
Doser
D000079:Acetaldehyde / Q000378:metabolism; D000428:Alcohol Drinking / Q000378:metabolism* / Q000473:pathology; D000444:Aldehyde Dehydrogenase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D000071396:Aldehyde Dehydrogenase, Mitochondrial; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis; D015153:Blotting, Western; D002540:Cerebral Cortex / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D000431:Ethanol / Q000008:administration & dosage / Q000633:toxicity; D005260:Female; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D020287:In Situ Nick-End Labeling; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D050050:Protein Carbonylation / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism
D051017:Apoptosis Regulatory Proteins; D000431:Ethanol; C096127:ALDH2 protein, human; D000444:Aldehyde Dehydrogenase; D000071396:Aldehyde Dehydrogenase, Mitochondrial; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D038362:Glycogen Synthase Kinase 3; D000079:Acetaldehyde