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Aldehyde dehydrogenase-2 (ALDH2) ameliorates chronic alcohol ingestion-induced myocardial insulin resistance and endoplasmic reticulum stress.

ABSTRACT: Chronic alcohol intake leads to insulin resistance and alcoholic cardiomyopathy, which appears to be a result of the complex interaction between genes and environment. This study was designed to examine the impact of aldehyde dehydrogenase-2 (ALDH2) transgenic overexpression on alcohol-induced insulin resistance and myocardial injury. ALDH2 transgenic mice were produced using chicken beta-actin promoter. Wild-type FVB and ALDH2 mice were fed a 4% alcohol or control diet for 12 weeks. Cell shortening was evaluated using an edge-detection system. Western blot analysis was used to assess insulin signaling at the levels of receptor, IRS, Akt, GSK-3beta, the transcription factors Foxo3a, c-Jun amino-terminal kinase (JNK) and c-Jun. Chronic alcohol intake led to glucose intolerance, reduced glucose uptake, cardiac hypertrophy and reduced cell shortening, the effects of which were alleviated by ALDH2. ALDH2 significantly attenuated alcohol-induced decrease in the insulin-stimulated tyrosine phosphorylation and increase in serine phosphorylation of IRS. Phosphorylation of Akt, GSK-3beta and Foxo3a was reduced following alcohol intake, the effect of which was abrogated by ALDH2. Levels of JNK, c-Jun and their phosphorylation were elevated following chronic alcohol intake, which were obliterated by ALDH2. Transfection of H9C2 myoblast cells with Foxo3a adenovirus mimicked acetaldehyde-induced JNK activation and glucose uptake defect whereas the dominant negative Foxo3a ablated acetaldehyde-elicited insulin insensitivity. In addition, ALDH2 reversed alcohol-induced myocardial ER stress. These data revealed that ALDH2 overexpression antagonizes chronic alcohol intake-induced cardiac insulin insensitivity and contractile defect, possibly via improvement of insulin signaling at the levels of insulin receptor, IRS, Akt, Foxo3a and JNK.

SUBMITTER: Li SY

PROVIDER: S-EPMC2703697 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature

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Aldehyde dehydrogenase-2 (ALDH2) ameliorates chronic alcohol ingestion-induced myocardial insulin resistance and endoplasmic reticulum stress.

Li Shi-Yan SY Gilbert Sara A B SA Li Qun Q Ren Jun J

Journal of molecular and cellular cardiology 20090401 2

Chronic alcohol intake leads to insulin resistance and alcoholic cardiomyopathy, which appears to be a result of the complex interaction between genes and environment. This study was designed to examine the impact of aldehyde dehydrogenase-2 (ALDH2) transgenic overexpression on alcohol-induced insulin resistance and myocardial injury. ALDH2 transgenic mice were produced using chicken beta-actin promoter. Wild-type FVB and ALDH2 mice were fed a 4% alcohol or control diet for 12 weeks. Cell shorte ...[more]

PMID: 19344727

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Project description:AimsChronic alcohol abuse causes steatohepatitis with insulin resistance, which impairs hepatocellular growth, survival and metabolism. However, growing evidence supports the concept that progressive alcohol-related liver injury may be mediated by concurrent mal-signaling through other networks that promote insulin resistance, e.g. pro-inflammatory, pro-ceramide and endoplasmic reticulum (ER) stress cascades.MethodsUsing the Long Evans rat model of chronic ethanol feeding, we characterized the histopathologic and ultrastructural features of steatohepatitis in relation to biochemical and molecular indices of tissue injury, inflammation, insulin resistance, dysregulated lipid metabolism and ER stress.ResultsChronic steatohepatitis with early chicken-wire fibrosis was associated with enlargement of mitochondria and disruption of ER structure by electron microscopy, elevated indices of lipid storage, lipid peroxidation and DNA damage, increased activation of pro-inflammatory cytokines, impaired signaling through the insulin receptor (InR), InR substrate-1, Akt, ribosomal protein S6 kinase and proline-rich Akt substrate 40 kDa, glycogen synthase kinase 3? activation and constitutive up-regulation of ceramide and ER stress-related genes. Liquid chromatography coupled with tandem mass spectrometry demonstrated altered ceramide profiles with higher levels of C14 and C18, and reduced C16 species in ethanol-exposed livers.ConclusionThe histopathologic and ultrastructural abnormalities in chronic alcohol-related steatohepatitis are associated with persistent hepatic insulin resistance and pro-inflammatory cytokine activation, dysregulated lipid metabolism with altered ceramide profiles and both ER and oxidative stress. Corresponding increases in lipid peroxidation, DNA damage and protein carbonylation may have contributed to the chronicity and progression of disease. The findings herein suggest that multi-pronged therapeutic strategies may be needed for effective treatment of chronic alcoholic liver disease in humans.

Dataset Information

Aldehyde dehydrogenase-2 (ALDH2) ameliorates chronic alcohol ingestion-induced myocardial insulin resistance and endoplasmic reticulum stress.

Publications

Aldehyde dehydrogenase-2 (ALDH2) ameliorates chronic alcohol ingestion-induced myocardial insulin resistance and endoplasmic reticulum stress.

Similar Datasets

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