An iTRAQ proteomic study reveals an association between diet-induced enhanced fatty acid metabolism and the development of glucose intolerance in prediabetic mice

Jennifer H. Ho, Oscar K. Lee, Yun Ju Fu, Hung Ta Shih, Chien Yu Tseng, Cheng Chih Chung, Chia Li Han, Yu Ju Chen

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

High-fat diet (HFD)-induced glucose intolerance and insulin resistance increases the chances of developing type-2 diabetes and cardiovascular disease. To study the mechanism(s) by which a HFD impairs glucose tolerance, we used a quantitative proteomic platform that integrated pI-based OFFGEL fractionation and iTRAQ labeling to profile the temporal changes in adipose membrane protein expression in mice fed a HFD for up to 8 months. Within 2 months of starting the diet, the mice adipose and liver tissues accumulated fat droplets, which contributed to subsequent insulin resistance and glucose intolerance within 6 months. The membrane proteomic delineation of such phenotypic expression resulted in quantification of 1713 proteins with 266, 343, and 125 differentially expressed proteins in 2-, 6-, and 8-month HFD-fed versus control mice, respectively. Pathway analysis of these differentially expressed proteins revealed the interplay between upregulation of fatty acid metabolism and downregulation of glucose metabolism. Substantial upregulation of adipose and liver carnitine palmitoyltransferase (Cpt) 1, the rate-limiting enzyme in the transport of long-chain fatty acids into mitochondria, occurred by 2 months. The increase in hepatic Cpt 1a expression was associated with a progressive decrease in glucose uptake as evidenced by downregulation of the liver glucose transporter protein (Glut) 2. Loss of glycogen storage was found in those hepatocytes full of fat droplets. Intriguingly, skeletal muscle Cpt 1b expression was unaltered by the HFD, whereas skeletal muscle Glut 4 and tyrosine phosphoryated insulin receptor substrate 1 (p-IRS1) were substantially upregulated at the same time as abnormal glucose metabolism developed in adipose and liver tissues. This study defines some of the molecular mechanisms as well as the relationship among adipose tissue, liver and skeletal muscle during development of HFD-induced glucose intolerance in vivo and identifies Cpt 1 as a potential drug target for the control or prevention of diabetes.

Original languageEnglish
Pages (from-to)1120-1133
Number of pages14
JournalJournal of Proteome Research
Volume12
Issue number3
DOIs
Publication statusPublished - 2013

Keywords

  • fatty acid metabolism
  • glucose intolerance
  • high-fat diet
  • insulin resistance
  • iTRAQ

ASJC Scopus subject areas

  • Biochemistry
  • Chemistry(all)

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