Effect of modulation of PPAR-γ activity on Kupffer cells M1/M2 polarization in the development of non-alcoholic fatty liver disease

Sci Rep. 2017 Mar 16:7:44612. doi: 10.1038/srep44612.

Abstract

Abnormal lipid-mediated hepatic inflammatory-immune dysfunction and chronic low grade inflammation play an important role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Macrophage polarization is an important mechanism for the regulation of inflammatory response. Since PPAR-γ has emerged as a master regulator of macrophage polarization, we aimed to investigate the lipid-induced macrophage/Kupffer cell polarization in vivo and in vitro, and explore the association between PPAR-γ activity and macrophages M1/M2 polarization shifting. Here we showed that long-term high-fat diet increased Kupffer cells content with M1-predominant phenotype and increasing production of pro-inflammatory cytokines. Saturated fatty acids polarized Kupffer cells/macrophages to an M1-predominant phenotype while n-3 PUFA polarized Kupffer cells/macrophages to an M2 phenotype, which was associated with activation of NF-κB signal pathway and PPAR-γ respectively. Furthermore, up-regulation of PPAR-γ shifted lipid-induced macrophages polarization from M1-predominant phenotype to M2 phenotype. Macrophages polarization switch was associated with the interaction between PPAR-γ and NF-κBp65 signal pathway. Rosiglitazone restored high-fat diet-induced imblance of Kupffer cells M1/M2 polarization and alleviated hepatic steatosis as well as local pro-inflammatory response. These findings suggest that manipulation of PPAR-γ activity has the potential to balance lipid-induced M1/M2 macrophage/Kupffer cell polarization, and leading to prevent the development of NAFLD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Polarity*
  • Diet, High-Fat
  • Inflammation / pathology
  • Kupffer Cells / metabolism*
  • Kupffer Cells / pathology*
  • Lipids / chemistry
  • Macrophages / metabolism*
  • Macrophages / pathology*
  • Mice
  • Mice, Inbred C57BL
  • NF-kappa B / metabolism
  • Non-alcoholic Fatty Liver Disease / metabolism*
  • Non-alcoholic Fatty Liver Disease / pathology*
  • PPAR gamma / agonists
  • PPAR gamma / metabolism*
  • Protein Binding
  • RAW 264.7 Cells
  • Signal Transduction

Substances

  • Lipids
  • NF-kappa B
  • PPAR gamma