Gemfibrozil, a lipid-lowering drug, induces suppressor of cytokine signaling 3 in glial cells: implications for neurodegenerative disorders

J Biol Chem. 2012 Aug 3;287(32):27189-203. doi: 10.1074/jbc.M112.346932. Epub 2012 Jun 8.

Abstract

Glial inflammation is an important feature of several neurodegenerative disorders. Suppressor of cytokine signaling (SOCS) proteins play a crucial role in inhibiting cytokine signaling and inflammatory gene expression in various cell types, including glial cells. However, mechanisms by which SOCS genes could be up-regulated are poorly understood. This study underlines the importance of gemfibrozil, a Food and Drug Administration-approved lipid-lowering drug, in up-regulating the expression of SOCS3 in glial cells. Gemfibrozil increased the expression of Socs3 mRNA and protein in mouse astroglia and microglia in both a time- and dose-dependent manner. Interestingly, gemfibrozil induced the activation of type IA phosphatidylinositol (PI) 3-kinase and AKT. Accordingly, inhibition of PI 3-kinase and AKT by chemical inhibitors abrogated gemfibrozil-mediated up-regulation of SOCS3. Furthermore, we demonstrated that gemfibrozil induced the activation of Krüppel-like factor 4 (KLF4) via the PI 3-kinase-AKT pathway and that siRNA knockdown of KLF4 abrogated gemfibrozil-mediated up-regulation of SOCS3. Gemfibrozil also induced the recruitment of KLF4 to the distal, but not proximal, KLF4-binding site of the Socs3 promoter. This study delineates a novel property of gemfibrozil in up-regulating SOCS3 in glial cells via PI 3-kinase-AKT-mediated activation of KLF4 and suggests that gemfibrozil may find therapeutic application in neuroinflammatory and neurodegenerative disorders.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Base Sequence
  • Cells, Cultured
  • DNA Primers
  • Gemfibrozil / pharmacology*
  • Humans
  • Hypolipidemic Agents / pharmacology*
  • Kruppel-Like Factor 4
  • Neurodegenerative Diseases / metabolism*
  • RNA, Messenger / genetics
  • Suppressor of Cytokine Signaling 3 Protein
  • Suppressor of Cytokine Signaling Proteins / genetics
  • Suppressor of Cytokine Signaling Proteins / metabolism*

Substances

  • DNA Primers
  • Hypolipidemic Agents
  • KLF4 protein, human
  • Klf4 protein, mouse
  • Kruppel-Like Factor 4
  • RNA, Messenger
  • Socs3 protein, mouse
  • Suppressor of Cytokine Signaling 3 Protein
  • Suppressor of Cytokine Signaling Proteins
  • Gemfibrozil