Caveolin-1 deficiency leads to increased susceptibility to cell death and fibrosis in white adipose tissue: characterization of a lipodystrophic model

PLoS One. 2012;7(9):e46242. doi: 10.1371/journal.pone.0046242. Epub 2012 Sep 26.

Abstract

Caveolin-1 (CAV1) is an important regulator of adipose tissue homeostasis. In the present study we examined the impact of CAV1 deficiency on the properties of mouse adipose tissue both in vivo and in explant cultures during conditions of metabolic stress. In CAV1(-/-) mice fasting caused loss of adipose tissue mass despite a lack of hormone-sensitive lipase (HSL) phosphorylation. In addition, fasting resulted in increased macrophage infiltration, enhanced deposition of collagen, and a reduction in the level of the lipid droplet protein perilipin A (PLIN1a). Explant cultures of CAV1(-/-) adipose tissue also showed a loss of PLIN1a during culture, enhanced secretion of IL-6, increased release of lactate dehydrogenase, and demonstrated increased susceptibility to cell death upon collagenase treatment. Attenuated PKA-mediated signaling to HSL, loss of PLIN1a and increased secretion of IL-6 were also observed in adipose tissue explants of CAV1(+/+) mice with diet-induced obesity. Together these results suggest that while alterations in adipocyte lipid droplet biology support adipose tissue metabolism in the absence of PKA-mediated pro-lipolytic signaling in CAV1(-/-) mice, the tissue is intrinsically unstable resulting in increased susceptibility to cell death, which we suggest underlies the development of fibrosis and inflammation during periods of metabolic stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorptiometry, Photon
  • Adipose Tissue, White / cytology
  • Adipose Tissue, White / metabolism*
  • Adipose Tissue, White / pathology*
  • Animals
  • Blotting, Western
  • Body Weight / genetics
  • Body Weight / physiology
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Caveolin 1 / deficiency
  • Caveolin 1 / genetics
  • Caveolin 1 / metabolism*
  • Cell Death / genetics
  • Cell Death / physiology
  • Fibrosis / genetics
  • Fibrosis / metabolism*
  • Immunohistochemistry
  • Interleukin-6 / metabolism
  • Lipolysis / genetics
  • Lipolysis / physiology
  • Male
  • Mice
  • Mice, Knockout
  • Perilipin-1
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism
  • Phosphorylation

Substances

  • Carrier Proteins
  • Caveolin 1
  • Interleukin-6
  • Perilipin-1
  • Phosphoproteins

Grants and funding

This work was supported by grants from the National Health and Medical Research Council of Australia (to RGP, grant numbers 511005 and 569452, and RGP and SM, grant number 455865) (www.nhmrc.gov.au) and Diabetes Australia (SM) (www.diabetesaustralia.com.au). MAF was an MEC/Fulbright Postdoctoral Fellow (Ministry of Education and Science, Spain). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.