Role for high-glucose-induced protein O-GlcNAcylation in stimulating cardiac fibroblast collagen synthesis

Am J Physiol Cell Physiol. 2014 May 1;306(9):C794-804. doi: 10.1152/ajpcell.00251.2013. Epub 2014 Feb 19.

Abstract

Excess enzyme-mediated protein O-GlcNAcylation is known to occur with diabetes mellitus. A characteristic of diabetic cardiomyopathy is the development of myocardial fibrosis. The role that enhanced protein O-GlcNAcylation plays in modulating the phenotype of cardiac fibroblasts (CF) is unknown. To address this issue, rat CF were cultured in normal glucose (NG; 5 mM glucose) or high-glucose (HG; 25 mM) media for 48 h. Results demonstrate that CF cultured in HG have higher levels (~50%) of overall protein O-GlcNAcylation vs. NG cells. Key regulators of collagen synthesis such as transforming-growth factor-β1 (TGF-β1), SMADs 2/3, and SMAD 7 protein levels, including those of arginase I and II, were altered, leading to increases in collagen levels. The nuclear transcription factor Sp1 and arginase II evidence excess O-GlcNAcylation in HG cells. Expression in CF of an adenovirus coding for the enzyme N-acetylglucosaminidase, which removes O-GlcNAc moieties from proteins, decreased Sp1 and arginase II O-GlcNAcylation and restored HG-induced perturbations in CF back to NG levels. These findings may have important pathophysiological implications for the development of diabetes-induced cardiac fibrosis.

Keywords: cardiomyopathy; diabetes; fibroblast; fibrosis; glycosylation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylglucosaminidase / genetics
  • Acetylglucosaminidase / metabolism
  • Animals
  • Arginase / metabolism
  • Cells, Cultured
  • Collagen / biosynthesis*
  • Diabetic Cardiomyopathies / metabolism*
  • Diabetic Cardiomyopathies / pathology
  • Fibroblasts / metabolism*
  • Fibroblasts / pathology
  • Glucose / metabolism*
  • Glycosylation
  • Male
  • Myocardium / metabolism*
  • Myocardium / pathology
  • Protein Processing, Post-Translational*
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction
  • Smad Proteins / metabolism
  • Sp1 Transcription Factor / metabolism
  • Time Factors
  • Transfection
  • Transforming Growth Factor beta1 / metabolism
  • Up-Regulation

Substances

  • Smad Proteins
  • Sp1 Transcription Factor
  • TGFB1 protein, human
  • Transforming Growth Factor beta1
  • Collagen
  • Acetylglucosaminidase
  • Arg2 protein, rat
  • Arginase
  • arginase I, rat
  • Glucose