The MCP-1/CCR2 system has direct proinflammatory effects in human mesangial cells

Kidney Int. 2006 Mar;69(5):856-63. doi: 10.1038/sj.ki.5000197.

Abstract

Both inflammatory and haemodynamic factors have been implicated in the pathogenesis of diabetic and other progressive glomerulopathies. Mesangial cell exposure to mechanical stretch induces both intercellular adhesion molecule 1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) expression. CC Chemokine receptor 2 (CCR2), the cognate MCP-1 receptor, has been recently demonstrated in human mesangial cells (HMCs). We tested whether MCP-1 binding to CCR2 affects ICAM-1 expression in HMCs and, secondly, if stretch-induced ICAM-1 is mediated by MCP-1 via an autocrine mechanism. Serum-deprived HMCs were exposed to either rh-MCP-1 (0.1-1-10-50-100 ng/ml) or mechanical stretch in the presence and in the absence of RS102895, a specific CCR2 inhibitor. ICAM-1 expression was assessed both by immunofluorescence and cytofluorimetry. Monocyte-HMC interaction was tested by adhesion assay. CCR2 expression was studied by reverse transcriptase-polymerase chain reaction, immunoblotting, and flow cytometry. HMCs exposure to rh-MCP-1 induced a significant twofold increase in ICAM-1 expression at 24 h, leading to enhanced monocyte adhesion. This effect occurred via the CCR2 receptor as CCR2 was expressed in HMCs and CCR2 blockade prevented ICAM-1 upregulation. Stretch-induced ICAM-1 expression was not altered by CCR2 blockade and stretch significantly reduced CCR2 mRNA and protein expression via an MCP-1-independent mechanism. In conclusion, stretch and MCP-1 independently induce ICAM-1 expression in HMCs. Stretch-induced CCR2 downregulation may favour MCP-1 paracrine activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Adhesion
  • Cells, Cultured
  • Chemokine CCL2 / metabolism*
  • Down-Regulation
  • Humans
  • Inflammation Mediators / metabolism*
  • Intercellular Adhesion Molecule-1 / biosynthesis
  • Mesangial Cells / cytology
  • Mesangial Cells / metabolism*
  • Monocytes / cytology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptors, CCR2
  • Receptors, Chemokine / genetics
  • Receptors, Chemokine / metabolism*
  • Stress, Mechanical

Substances

  • CCL2 protein, human
  • CCR2 protein, human
  • Chemokine CCL2
  • Inflammation Mediators
  • RNA, Messenger
  • Receptors, CCR2
  • Receptors, Chemokine
  • Intercellular Adhesion Molecule-1