Introduction: Diabetic cardiomyopathy is characterized by oversupply of nutrients with concurrent loss of metabolic flexibility. Even in excess substrate availability the heart suffers energy depletion as metabolic fluxes are diminished. We established a stably GLUT4 overexpressing cell line derived from H9C2 that presents a diabetic cardiomyopathy like phenotype. Protein expression patterns are analyzed by proteomic approaches.
Material and Methods: Rat cardiomyoblasts stably overexpressing GLUT4 (H9C2-GLUT4) were cultured under hyperglycemic conditions (30mM glucose) either short time (3 days) or long time (more than 3 months). Expression profile was compared to non-transfected H9C2 cells (H9C2), using same culture conditions. Cell culture samples were prepared for mass spectrometric analysis by sample lysis followed by tryptic digestion. Peptides were analyzed on an Orbitrap Elite (ThermoFisher, Scientific) and resulting files were taken for the identification and quantification of proteins using MaxQuant and Perseus. DAVID Bioinformatics Resources 6.8 functioned as Pathway and GO term enrichment tool for further in depth analysis of the data set.
Results: We were able to quantify 2,841 proteins of whose 881 were found to be significantly regulated (5% FDR; ANOVA corrected p-value). Further analysis of long time and short time exposure of either WT or GLUT4 overexpressing cells lead to the identification of 135 significantly expressed proteins in the WT and 112 significantly expressed proteins in the H9C2-GLUT4 model (5% FDR; ANOVA corrected p-value). In depth pathway and GO term enrichment analysis support effects on metabolism, protein biosynthesis and handling, and ECM composition.
Discussion: Chronic glucose overload in cardiomyoblasts induced by GLUT4 overexpression and hyperglycemia resulted in a metabolic induced proteome profile change. These models may thus increase our knowledge of biological effects of chronic hyperglycemia on the diabetic heart.
B. Stratmann: Speaker’s Bureau; Self; AstraZeneca, Neoplas Tools GmbH. B. Eggers: None. Y. Mattern: None. K. Marcus: None. D. Tschoepe: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim International GmbH. Research Support; Self; AstraZeneca, Bayer AG, Boehringer Ingelheim International GmbH, Neoplas tools GmbH.