Systemic deficiency of the MAP kinase-activated protein kinase 2 reduces atherosclerosis in hypercholesterolemic mice

Circ Res. 2007 Nov 26;101(11):1104-12. doi: 10.1161/CIRCRESAHA.107.156075. Epub 2007 Sep 20.

Abstract

Atherosclerosis is a chronic inflammatory disease and represents the major cause of cardiovascular morbidity and mortality. A critical regulator of inflammatory processes represents the mitogen-activated protein kinase-activated protein kinase-2 (MK2). Therefore, we investigated the functional role of MK2 in atherogenesis in hypercholesterolemic mice as well as potentially underlying mechanisms in vivo and in vitro. Activation of MK2 (phospho-MK2) was predominantly detected in the endothelium and macrophage-rich plaque areas within aortas of hypercholesterolemic LDL receptor-deficient mice (ldlr(-/-)). Systemic MK2 deficiency of hypercholesterolemic ldlr(-/-) mice (ldlr(-/-)/mk2(-/-)) significantly decreased the accumulation of lipids and macrophages in the aorta after feeding an atherogenic diet for 8 and 16 weeks despite a significant increase in proatherogenic plasma lipoproteins compared with ldlr(-/-) mice. Deficiency of MK2 significantly decreased oxLDL-induced foam cell formation in vitro, diet-induced foam cell formation in vivo, and expression of scavenger receptor A in primary macrophages. In addition, systemic MK2 deficiency of hypercholesterolemic ldlr(-/-) mice significantly decreased the aortic expression of the adhesion molecule VCAM-1 and the chemokine MCP-1, key mediators of macrophage recruitment into the vessel wall. Furthermore, silencing of MK2 in endothelial cells by siRNA reduced the IL-1beta-induced expression of VCAM-1 and MCP-1. MK2 critically promotes atherogenesis by fostering foam cell formation and recruitment of monocytes/macrophages into the vessel wall. Therefore, MK2 might represent an attractive novel target for the treatment of atherosclerotic cardiovascular disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aorta / pathology
  • Atherosclerosis / enzymology*
  • Atherosclerosis / etiology
  • Atherosclerosis / prevention & control*
  • Chemokine CCL2 / analysis
  • Endothelium, Vascular / enzymology
  • Foam Cells / pathology
  • Hypercholesterolemia / complications*
  • Intracellular Signaling Peptides and Proteins / deficiency*
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Intracellular Signaling Peptides and Proteins / physiology
  • Lipoproteins / blood
  • Macrophages
  • Mice
  • Mice, Knockout
  • Phosphorylation
  • Protein Serine-Threonine Kinases / deficiency*
  • Protein Serine-Threonine Kinases / metabolism
  • Protein Serine-Threonine Kinases / physiology
  • Receptors, Scavenger / analysis
  • Vascular Cell Adhesion Molecule-1 / analysis

Substances

  • Chemokine CCL2
  • Intracellular Signaling Peptides and Proteins
  • Lipoproteins
  • Receptors, Scavenger
  • Vascular Cell Adhesion Molecule-1
  • MAP-kinase-activated kinase 2
  • Protein Serine-Threonine Kinases