T-cell cytokine induction of BMP-2 regulates human mesenchymal stromal cell differentiation and mineralization

J Cell Biochem. 2006 Jul 1;98(4):706-14. doi: 10.1002/jcb.20933.

Abstract

How T-cells, attracted to local sites of inflammation in arthritides, affect heterotopic ossification is presently unknown. Here, we tested the hypothesis that T-cell cytokines play a role in the differentiation of human mesenchymal stromal cells (HMSC) into the osteoblast phenotype by inducing autologous BMP-2, providing a possible mechanism for heterotopic ossification. HMSC from multiple donor bones were treated with either activated T-cell conditioned medium (ACTTCM) or physiological concentrations of the major inflammatory cytokines, TNF-alpha, TGF-beta, IFN-gamma, and IL-17 (TTII), individually or in combinations. ACTTCM induced BMP-2 protein in a time-dependent manner over a 48 h period and alkaline phosphatase (AlkP) within 7 days. In combination, TTII, like ACTTCM, induced AlkP and synergistically induced BMP-2 protein. Either individually, or in combinations of up to three, the T-cell cytokines failed to induce BMP-2 above control levels while a combination of all four cytokines synergistically induced BMP-2 10-fold as assessed by ELISA. TTII induced mineralized matrix as effectively as dexamethasone. Inhibition of p38 MAPK completely inhibited TTII-induced BMP-2 production and matrix mineralization. Real time RT-PCR analysis demonstrated a striking early (within 4 h) increase in BMP-2 gene expression by TTII, which was suppressed by p38 MAP kinase inhibition. In localized chronic inflammatory diseases, T-cell cytokines released at localized sites of inflammation may be the driving force for differentiation of local mesenchymal stromal cells into the osteoblast phenotype thereby playing a significant role in the heterotopic ossification observed in these diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arthritis / enzymology
  • Arthritis / pathology
  • Bone Marrow Cells / enzymology
  • Bone Marrow Cells / pathology
  • Bone Morphogenetic Protein 2
  • Bone Morphogenetic Proteins / biosynthesis*
  • Calcinosis / enzymology*
  • Calcinosis / pathology
  • Cell Differentiation*
  • Cell Movement
  • Cells, Cultured
  • Culture Media, Conditioned
  • Cytokines / metabolism*
  • Humans
  • Inflammation / enzymology
  • Inflammation / pathology
  • Signal Transduction
  • Stromal Cells / enzymology
  • Stromal Cells / pathology
  • T-Lymphocytes / metabolism*
  • T-Lymphocytes / pathology
  • Tissue Donors
  • Transforming Growth Factor beta / biosynthesis*

Substances

  • BMP2 protein, human
  • Bone Morphogenetic Protein 2
  • Bone Morphogenetic Proteins
  • Culture Media, Conditioned
  • Cytokines
  • Transforming Growth Factor beta