Glutathionylated Lipid Aldehydes Are Products of Adipocyte Oxidative Stress and Activators of Macrophage Inflammation

  1. David A. Bernlohr2
  1. 1Department of Pediatrics, University of Minnesota, Minneapolis, MN
  2. 2Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN
  1. Corresponding author: David A. Bernlohr, bernl001{at}umn.edu.
  1. B.I.F. and E.K.L. contributed equally to this work.

Abstract

Obesity-induced insulin resistance has been linked to adipose tissue lipid aldehyde production and protein carbonylation. Trans-4-hydroxy-2-nonenal (4-HNE) is the most abundant lipid aldehyde in murine adipose tissue and is metabolized by glutathione S-transferase A4 (GSTA4), producing glutathionyl-HNE (GS-HNE) and its metabolite glutathionyl-1,4-dihydroxynonene (GS-DHN). The objective of this study was to evaluate adipocyte production of GS-HNE and GS-DHN and their effect on macrophage inflammation. Compared with lean controls, GS-HNE and GS-DHN were more abundant in visceral adipose tissue of ob/ob mice and diet-induced obese, insulin-resistant mice. High glucose and oxidative stress induced production of GS-HNE and GS-DHN by 3T3-L1 adipocytes in a GSTA4-dependent manner, and both glutathionylated metabolites induced secretion of tumor necrosis factor-α from RAW 264.7 and primary peritoneal macrophages. Targeted microarray analysis revealed GS-HNE and GS-DHN induced expression of inflammatory genes, including C3, C4b, c-Fos, igtb2, Nfkb1, and Nos2. Transgenic overexpression of GSTA4 in mouse adipose tissue led to increased production of GS-HNE associated with higher fasting glucose levels and moderately impaired glucose tolerance. These results indicated adipocyte oxidative stress results in GSTA4-dependent production of proinflammatory glutathione metabolites, GS-HNE and GS-DHN, which may represent a novel mechanism by which adipocyte dysfunction results in tissue inflammation and insulin resistance.

Footnotes

  • Received May 15, 2013.
  • Accepted September 15, 2013.

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  1. Diabetes vol. 63 no. 1 89-100
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