The C-terminal module IV of connective tissue growth factor is a novel immune modulator of the Th17 response

Lab Invest. 2013 Jul;93(7):812-24. doi: 10.1038/labinvest.2013.67. Epub 2013 May 6.

Abstract

Connective tissue growth factor (CTGF/CCN2) is a matricellular protein susceptible to proteolytic degradation. CCN2 levels have been suggested as a potential risk biomarker in several chronic diseases. In body fluids, CCN2 full-length and its degradation fragments can be found; however, their in vivo effects are far from being elucidated. CCN2 was described as a profibrotic mediator, but this concept is changing to a proinflammatory cytokine. In vitro, CCN2 full-length and its C-terminal module IV (CCN2(IV)) exert proinflammatory properties. Emerging evidence suggest that Th17 cells, and its effector cytokine IL-17A, participate in chronic inflammatory diseases. Our aim was to explore whether CCN2(IV) could regulate the Th17 response. In vitro, stimulation of human naive CD4+ T lymphocytes with CCN2(IV) resulted in differentiation to Th17 phenotype. The in vivo effects of CCN2(IV) were studied in C57BL/6 mice. Intraperitoneal administration of recombinant CCN2(IV) did not change serum IL-17A levels, but caused an activation of the Th17 response in the kidney, characterized by interstitial infiltration of Th17 (IL17A+/CD4+) cells and upregulation of proinflammatory mediators. In CCN2(IV)-injected mice, elevated renal levels of Th17-related factors (IL-17A, IL-6, STAT3 and RORγt) were found, whereas Th1/Th2 cytokines or Treg-related factors (TGF-β and Foxp-3) were not modified. Treatment with an anti-IL-17A neutralizing antibody diminished CCN2(IV)-induced renal inflammation. Our findings unveil that the C-terminal module of CCN2 induces the Th17 differentiation of human Th17 cells and causes a renal Th17 inflammatory response. Furthermore, these data bear out that IL-17A targeting is a promising tool for chronic inflammatory diseases, including renal pathologies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Connective Tissue Growth Factor / administration & dosage
  • Connective Tissue Growth Factor / metabolism*
  • Humans
  • Interleukin-17 / blood*
  • Kidney / immunology*
  • Kidney / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Th17 Cells / physiology*
  • Transcription Factors / metabolism
  • Up-Regulation

Substances

  • CCN2 protein, human
  • CCN2 protein, mouse
  • Interleukin-17
  • Transcription Factors
  • Connective Tissue Growth Factor