Fatty acids differentially regulate insulin resistance through endoplasm reticulum stress-mediated induction of tribbles homologue 3: A potential link between dietary fat composition and the pathophysiological outcomes of obesity

T. Geng, W. Hu, M. H. Broadwater, J. M. Snider, J. Bielawski, S. B. Russo, J. H. Schwacke, J. Ross, L. A. Cowart

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

Aims/hypothesis: Previous studies have shown that saturated fatty acids cause insulin resistance (IR) that is prevented by unsaturated fatty acids. Tribbles homologue 3 (TRIB3) is a putative endogenous inhibitor of insulin signalling, but its role in insulin signalling is controversial. This study aimed to determine whether fatty acids regulate IR via TRIB3. Methods: We treated HepG2 cells with saturated and unsaturated fatty acids and evaluated TRIB3 expression. We then tested whether regulation of TRIB3 occurred through endoplasmic reticulum (ER) stress, and whether modulating TRIB3 and ER stress marker genes was necessary and/or sufficient for regulation of insulin signalling. To test the in vivo significance of this mechanism, we fed mice obesogenic diets with different fatty acid profiles and assessed physiological variables of diabetes, ER stress markers and Trib3 expression in the liver. Results: Our data show that fatty acids differentially regulate IR through ER stress-mediated induction of TRIB3. Intriguingly, a standard and widely used obesogenic diet high in unsaturated fats failed to induce ER stress, TRIB3 or IR. However, an alternative obesogenic diet with lower unsaturated fat recapitulated the cell studies by causing ER stress, TRIB3 induction and IR. Conclusions/interpretation: This study revealed a novel mechanism linking dietary fat composition to IR. Given the emerging roles for ER stress in non-alcoholic liver disease, we conclude that dietary fat composition rather than total amount may mediate hepatic pathology associated with obesity.

Original languageEnglish (US)
Pages (from-to)2078-2087
Number of pages10
JournalDiabetologia
Volume56
Issue number9
DOIs
StatePublished - Sep 2013
Externally publishedYes

Keywords

  • Animal model
  • Diet-induced obesity
  • ER stress
  • Insulin resistance
  • NEFA
  • Trib3

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

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