Sexually dimorphic diet-induced insulin resistance in obese tissue inhibitor of metalloproteinase-2 (TIMP-2)-deficient mice

Endocrinology. 2011 Apr;152(4):1300-13. doi: 10.1210/en.2010-1029. Epub 2011 Feb 1.

Abstract

Circulating levels of matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitor of metalloproteinases (TIMPs), are altered in human obesity and may contribute to its pathology. TIMP-2 exerts MMP-dependent (MMP inhibition and pro-MMP-2 activation) and MMP-independent functions. To assess the role of TIMP-2 in a murine model of nutritionally induced obesity, weight gain in wild-type and TIMP-2 deficient [knockout (KO)] mice fed a chow or high-fat diet (HFD) was determined. The effects of diet on glucose tolerance and insulin sensitivity, as well as pancreatic β-cell and adipocyte physiology, were assessed. Chow-fed TIMP-2 KO mice of both sexes became obese but maintained relatively normal glucose tolerance and insulin sensitivity. Obesity was exacerbated on the HFD. However, HFD-fed male, but not female, TIMP-2 KO mice developed insulin resistance with reduced glucose transporter 2 and pancreatic and duodenal homeobox 1 levels, despite increased β-cell mass and hyperplasia. Thus, although β-cell mass was increased, HFD-fed male TIMP-2 KO mice develop diabetes likely due to β-cell exhaustion and failure. TIMP-2 mRNA, whose expression was greatest in sc adipose tissue, was down-regulated in HFD-fed wild-type males, but not females. Furthermore, HFD increased membrane type 1-MMP (MMP-14) expression and activity in male, but not female, sc adipose tissue. Strikingly, MMP-14 expression increased to a greater extent in TIMP-2 KO males and was associated with decreased adipocyte collagen. Taken together, these findings demonstrate a role for TIMP-2 in maintaining extracellular matrix integrity necessary for normal β-cell and adipocyte physiology and that loss of extracellular matrix integrity may underlie diabetic and obesogenic phenotypes.

Publication types

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

MeSH terms

  • Adipocytes / metabolism
  • Adipose Tissue / metabolism
  • Animals
  • Blotting, Western
  • Dietary Fats / adverse effects
  • Female
  • Immunoenzyme Techniques
  • Insulin Resistance / genetics
  • Insulin Resistance / physiology
  • Insulin-Secreting Cells / metabolism
  • Leptin / metabolism
  • Male
  • Matrix Metalloproteinase 14 / metabolism
  • Mice
  • Mice, Knockout
  • Microscopy, Confocal
  • Microscopy, Fluorescence
  • Obesity / chemically induced
  • Obesity / metabolism*
  • Polymerase Chain Reaction
  • Sex Factors
  • Tissue Inhibitor of Metalloproteinase-2 / deficiency*
  • Tissue Inhibitor of Metalloproteinase-2 / genetics
  • Tissue Inhibitor of Metalloproteinase-2 / metabolism*
  • Weight Gain / genetics

Substances

  • Dietary Fats
  • Leptin
  • Tissue Inhibitor of Metalloproteinase-2
  • Matrix Metalloproteinase 14