Genetic loss of insulin receptors worsens cardiac efficiency in diabetes

Heiko Bugger, Christian Riehle, Bharat Jaishy, Adam R. Wende, Joseph Tuinei, Dong Chen, Jamie Soto, Karla M. Pires, Sihem Boudina, Heather A. Theobald, Ivan Luptak, Benjamin Wayment, Xiaohui Wang, Sheldon E. Litwin, Bart C Weimer, E. Dale Abel

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

Aims: To determine the contribution of insulin signaling versus systemic metabolism to metabolic and mitochondrial alterations in type 1 diabetic hearts and test the hypothesis that antecedent mitochondrial dysfunction contributes to impaired cardiac efficiency (CE) in diabetes. Methods and results: Control mice (WT) and mice with cardiomyocyte-restricted deletion of insulin receptors (CIRKO) were rendered diabetic with streptozotocin (WT-STZ and CIRKO-STZ, respectively), non-diabetic controls received vehicle (citrate buffer). Cardiac function was determined by echocardiography; myocardial metabolism, oxygen consumption (MVO 2) and CE were determined in isolated perfused hearts; mitochondrial function was determined in permeabilized cardiac fibers and mitochondrial proteomics by liquid chromatography mass spectrometry. Pyruvate supported respiration and ATP synthesis were equivalently reduced by diabetes and genotype, with synergistic impairment in ATP synthesis in CIRKO-STZ. In contrast, fatty acid delivery and utilization was increased by diabetes irrespective of genotype, but not in non-diabetic CIRKO. Diabetes and genotype synergistically increased MVO 2 in CIRKO-STZ, leading to reduced CE. Irrespective of diabetes, genotype impaired ATP/O ratios in mitochondria exposed to palmitoyl carnitine, consistent with mitochondrial uncoupling. Proteomics revealed reduced content of fatty acid oxidation proteins in CIRKO mitochondria, which were induced by diabetes, whereas tricarboxylic acid cycle and oxidative phosphorylation proteins were reduced both in CIRKO mitochondria and by diabetes. Conclusions: Deficient insulin signaling and diabetes mediate distinct effects on cardiac mitochondria. Antecedent loss of insulin signaling markedly impairs CE when diabetes is induced, via mechanisms that may be secondary to mitochondrial uncoupling and increased FA utilization.

Original languageEnglish (US)
Pages (from-to)1019-1026
Number of pages8
JournalJournal of Molecular and Cellular Cardiology
Volume52
Issue number5
DOIs
StatePublished - May 2012

Keywords

  • Cardiac efficiency
  • Diabetes
  • Diabetic cardiomyopathy
  • Insulin signaling
  • Mitochondria

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

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  • Cite this

    Bugger, H., Riehle, C., Jaishy, B., Wende, A. R., Tuinei, J., Chen, D., Soto, J., Pires, K. M., Boudina, S., Theobald, H. A., Luptak, I., Wayment, B., Wang, X., Litwin, S. E., Weimer, B. C., & Abel, E. D. (2012). Genetic loss of insulin receptors worsens cardiac efficiency in diabetes. Journal of Molecular and Cellular Cardiology, 52(5), 1019-1026. https://doi.org/10.1016/j.yjmcc.2012.02.001