The MCP-1/CCR2 axis in podocytes is involved in apoptosis induced by diabetic conditions

Apoptosis. 2012 Jan;17(1):1-13. doi: 10.1007/s10495-011-0661-6.

Abstract

Previous studies have demonstrated the importance of monocyte chemoattractant protein-1 (MCP-1) in the pathogenesis of diabetic nephropathy in terms of inflammation, but the direct role of the MCP-1/CCR2 system on podocyte apoptosis under diabetic conditions has never been explored. In vitro, mouse podocytes were exposed to a medium containing 30 mM glucose (HG) with or without CCR2 siRNA or CCR2 inhibitor (RS102895). Podocytes were also treated with MCP-1 or TGF-β1 with or without anti-TGF-β1 antibody, CCR2 siRNA, or CCR2 inhibitor. In vivo, 20 db/m and 20 db/db mice were divided into two groups, and ten mice from each group were treated with RS102895. Western blot and Hoechst 33342 or TUNEL staining were performed to identify apoptosis. HG-induced apoptosis and TGF-β1 levels were significantly abrogated by CCR2 inhibition. In addition, treatment with MCP-1 directly induced apoptosis via CCR2. Moreover, TGF-β1- and MCP-1-induced apoptosis were significantly ameliorated by the inhibition of CCR2 and anti-TGF-β1 antibody, respectively. Glomerular expression of cleaved caspase-3 and apoptotic cells within glomeruli were also significantly increased in db/db mice compared to db/m mice, and these increases were significantly attenuated in db/db + RS102895 mice. These results suggest that interactions between the MCP-1/CCR2 system and TGF-β1 may contribute to podocyte apoptosis under diabetic conditions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis*
  • Cells, Cultured
  • Chemokine CCL2 / genetics
  • Chemokine CCL2 / metabolism*
  • Diabetic Nephropathies / genetics
  • Diabetic Nephropathies / metabolism
  • Diabetic Nephropathies / physiopathology*
  • Disease Models, Animal
  • Female
  • Glucose
  • Humans
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Podocytes / cytology*
  • Podocytes / metabolism
  • Receptors, CCR2 / genetics
  • Receptors, CCR2 / metabolism*
  • Transforming Growth Factor beta1 / metabolism

Substances

  • Ccl2 protein, mouse
  • Ccr2 protein, mouse
  • Chemokine CCL2
  • Receptors, CCR2
  • Transforming Growth Factor beta1
  • Glucose