Dataset Information

Glucose transporter 4-deficient hearts develop maladaptive hypertrophy in response to physiological or pathological stresses.

ABSTRACT: Pathological cardiac hypertrophy may be associated with reduced expression of glucose transporter 4 (GLUT4) in contrast to exercise-induced cardiac hypertrophy, where GLUT4 levels are increased. However, mice with cardiac-specific deletion of GLUT4 (G4H-/-) have normal cardiac function in the unstressed state. This study tested the hypothesis that cardiac GLUT4 is required for myocardial adaptations to hemodynamic demands. G4H-/- and control littermates were subjected to either a pathological model of left ventricular pressure overload [transverse aortic constriction (TAC)] or a physiological model of endurance exercise (swim training). As predicted after TAC, G4H-/- mice developed significantly greater hypertrophy and more severe contractile dysfunction. Somewhat surprisingly, after exercise training, G4H-/- mice developed increased fibrosis and apoptosis that was associated with dephosphorylation of the prosurvival kinase Akt in concert with an increase in protein levels of the upstream phosphatase protein phosphatase 2A (PP2A). Exercise has been shown to decrease levels of ceramide; G4H-/- hearts failed to decrease myocardial ceramide in response to exercise. Furthermore, G4H-/- hearts have reduced levels of the transcriptional coactivator peroxisome proliferator-activated receptor-? coactivator-1, lower carnitine palmitoyl-transferase activity, and reduced hydroxyacyl-CoA dehydrogenase activity. These basal changes may also contribute to the impaired ability of G4H-/- hearts to adapt to hemodynamic stresses. In conclusion, GLUT4 is required for the maintenance of cardiac structure and function in response to physiological or pathological processes that increase energy demands, in part through secondary changes in mitochondrial metabolism and cellular stress survival pathways such as Akt.NEW & NOTEWORTHY Glucose transporter 4 (GLUT4) is required for myocardial adaptations to exercise, and its absence accelerates heart dysfunction after pressure overload. The requirement for GLUT4 may extend beyond glucose uptake to include defects in mitochondrial metabolism and survival signaling pathways that develop in its absence. Therefore, GLUT4 is critical for responses to hemodynamic stresses.

SUBMITTER: Wende AR

PROVIDER: S-EPMC5814656 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Glucose transporter 4-deficient hearts develop maladaptive hypertrophy in response to physiological or pathological stresses.

Wende Adam R AR Kim Jaetaek J Holland William L WL Wayment Benjamin E BE O'Neill Brian T BT Tuinei Joseph J Brahma Manoja K MK Pepin Mark E ME McCrory Mark A MA Luptak Ivan I Halade Ganesh V GV Litwin Sheldon E SE Abel E Dale ED

American journal of physiology. Heart and circulatory physiology 20170819 6

Pathological cardiac hypertrophy may be associated with reduced expression of glucose transporter 4 (GLUT4) in contrast to exercise-induced cardiac hypertrophy, where GLUT4 levels are increased. However, mice with cardiac-specific deletion of GLUT4 (G4H<sup>-/-</sup>) have normal cardiac function in the unstressed state. This study tested the hypothesis that cardiac GLUT4 is required for myocardial adaptations to hemodynamic demands. G4H<sup>-/-</sup> and control littermates were subjected to ei ...[more]

PMID: 28822962

Similar Datasets

Project description:Compelling evidence suggests that mitochondrial dysfunction contributes to the pathogenesis of heart failure, including defects in the substrate oxidation, and the electron transport chain (ETC) and oxidative phosphorylation (OXPHOS). However, whether such changes occur early in the development of heart failure, and are potentially involved in the pathologic events that lead to cardiac dysfunction is unknown. To address this question, we conducted transcriptomic/metabolomics profiling in hearts of mice with two progressive stages of pressure overload-induced cardiac hypetrophy: i) cardiac hypertrophy with preserved ventricular function achieved via transverse aortic constriction for 4 weeks (TAC) and ii) decompensated cardiac hypertrophy or heart failure (HF) caused by combining 4 wk TAC with a small apical myocardial infarction. Transcriptomic analyses revealed, as shown previously, downregulated expression of genes involved in mitochondrial fatty acid oxidation in both TAC and HF hearts compared to sham-operated control hearts. Surprisingly, however, there were very few changes in expression of genes involved in other mitochondrial energy transduction pathways, ETC, or OXPHOS. Metabolomic analyses demonstrated significant alterations in pathway metabolite levels in HF (but not in TAC), including elevations in acylcarnitines, a subset of amino acids, and the lactate/pyruvate ratio. In contrast, the majority of organic acids were lower than controls. This metabolite profile suggests “bottlenecks” in the carbon substrate input to the TCA cycle. This transcriptomic/metabolomic profile was markedly different from that of mice PGC-1a/b deficiency in which a global downregulation of genes involved in mitochondrial ETC and OXPHOS was noted. In addition, the transcriptomic/metabolomic signatures of HF differed markedly from that of the exercise-trained mouse heart. We conclude that in contrast to current dogma, alterations in mitochondrial metabolism that occur early in the development of heart failure reflect largely post-transcriptional mechanisms resulting in impedance to substrate flux into the TCA cycle, reflected by alterations in the metabolome. Microarray gene expression profiling was performed with bi-ventricle RNA isolated from (1) 3 month-old female C57Bl6/J mice with transverse aortic constriction (CH), vs sham-operated control (Sham-CH), (2) 3 month-old female C57Bl6/J mice with heart failure (HF), vs. sham-operated control (Sham-HF); (3) 2 month-old female C57Bl6/J mice with voluntary wheel training for 2 months (Run), vs. Sedentary control (Sed). Five biological replicates are included for each group.

Dataset Information

Glucose transporter 4-deficient hearts develop maladaptive hypertrophy in response to physiological or pathological stresses.

Publications

Glucose transporter 4-deficient hearts develop maladaptive hypertrophy in response to physiological or pathological stresses.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets