A CD36-dependent Signaling Cascade Is Necessary for Macrophage Foam Cell Formation

Cell Metab. 2006 Sep;4(3):211-21. doi: 10.1016/j.cmet.2006.06.007.

Abstract

Accumulation of macrophage foam cells in atherosclerotic blood vessel intima is a critical component of atherogenesis mediated by scavenger receptor-dependent internalization of oxidized LDL. We demonstrated by coimmunoprecipitation and pull-down assays that the macrophage scavenger receptor CD36 associates with a signaling complex containing Lyn and MEKK2. The MAP kinases JNK1 and JNK2 were specifically phosphorylated in macrophages exposed to oxLDL. Using cells isolated from SRA, TLR2, or CD36 null mice, and phospholipid ligands specific for either SRA or CD36, we showed that JNK activation was mediated by CD36. Both foam cell formation and activation of JNK2 in hyperlipidemic mice were diminished in the absence of CD36. Furthermore, inhibition of Src or JNK blocked oxLDL uptake and inhibited foam cell formation in vitro and in vivo. These findings show that a specific CD36-dependent signaling pathway initiated by oxLDL is necessary for foam cell formation and identify potential targets for antiatherosclerosis therapy.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Atherosclerosis / drug therapy
  • Atherosclerosis / metabolism*
  • Atherosclerosis / physiopathology
  • CD36 Antigens / metabolism*
  • Endothelial Cells / metabolism
  • Enzyme Inhibitors / pharmacology
  • Female
  • Foam Cells / metabolism*
  • Hyperlipidemias / metabolism*
  • Hyperlipidemias / physiopathology
  • Hypolipidemic Agents / pharmacology
  • Lipoproteins, LDL / metabolism
  • MAP Kinase Kinase Kinase 2 / metabolism
  • Macrophages / metabolism*
  • Male
  • Mice
  • Mice, Knockout
  • Mitogen-Activated Protein Kinase 9 / antagonists & inhibitors
  • Mitogen-Activated Protein Kinase 9 / metabolism
  • Oxidation-Reduction
  • Phosphorylation
  • Signal Transduction / physiology*
  • Toll-Like Receptor 2 / metabolism
  • src-Family Kinases / antagonists & inhibitors
  • src-Family Kinases / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • CD36 Antigens
  • Enzyme Inhibitors
  • Hypolipidemic Agents
  • Lipoproteins, LDL
  • Sra-1 protein, mouse
  • Tlr2 protein, mouse
  • Toll-Like Receptor 2
  • oxidized low density lipoprotein
  • Mitogen-Activated Protein Kinase 9
  • lyn protein-tyrosine kinase
  • src-Family Kinases
  • MAP Kinase Kinase Kinase 2
  • Map3k2 protein, mouse