Mesenchymal stem cells produce Wnt isoforms and TGF-beta1 that mediate proliferation and procollagen expression by lung fibroblasts

Am J Physiol Lung Cell Mol Physiol. 2009 Nov;297(5):L1002-11. doi: 10.1152/ajplung.90347.2008. Epub 2009 Sep 4.


Studies have been carried out previously to determine whether mesenchymal stem cells (MSC) influence the progression of pulmonary fibrosis. Here, we asked whether MSC (derived from mouse bone marrow and human umbilical cord blood) produce factors that mediate lung fibroblast (LF) growth and matrix production. MSC-conditioned media (CM) were found by ELISA to contain significant amounts of PDGF-AA and transforming growth factor-beta1 (TGF-beta1). Proliferation was increased in a concentration-dependent manner in LF cell lines and primary cells cultured in MSC-CM, but neither anti-PDGF antibodies nor PDGF receptor-specific antibodies affected proliferation, nor did a number of other antibodies to well-known mitogenic factors. However, proliferation was significantly inhibited by the Wnt signaling antagonist, secreted frizzled related protein-1 (sFRP-1). In addition, anti-Wnt1 and anti-Wnt2 antibodies attenuated MSC-CM-induced proliferation, and increased expression of Wnt7b was identified. As would be expected in cells activated by Wnt, nuclear beta-catenin was increased. The amount of TGF-beta1 in MSC-CM and its biological activity were revealed by activation at acidic pH. The stem cells synthesized and released TGF-beta1 that increased alpha1-procollagen gene expression by LF target cells. Addition of anti-TGF-beta to the MSC-CM blocked upregulation of collagen gene expression. These data demonstrate that MSC from mice and humans produce Wnt proteins and TGF-beta1 that respectively stimulate LF proliferation and matrix production, two hallmarks of fibroproliferative lung disease. It will be essential to determine whether these factors can play a role in attempts to use MSC for therapeutic approaches.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antibodies / pharmacology
  • Bone Marrow Cells / cytology
  • Cell Proliferation / drug effects
  • Coculture Techniques
  • Collagen Type I / genetics
  • Collagen Type I / metabolism*
  • Culture Media, Conditioned / pharmacology
  • Fetal Blood / cytology
  • Fibroblasts / cytology*
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism*
  • Gene Expression Regulation / drug effects
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Lung / cytology*
  • Mesenchymal Stem Cells / cytology
  • Mesenchymal Stem Cells / drug effects
  • Mesenchymal Stem Cells / metabolism*
  • Mice
  • Platelet-Derived Growth Factor / metabolism
  • Polymerase Chain Reaction
  • Protein Isoforms / metabolism
  • Proteins / pharmacology
  • Solubility / drug effects
  • Transforming Growth Factor beta1 / antagonists & inhibitors
  • Transforming Growth Factor beta1 / metabolism*
  • Wnt Proteins / metabolism*
  • beta Catenin / metabolism


  • Antibodies
  • Collagen Type I
  • Culture Media, Conditioned
  • Intracellular Signaling Peptides and Proteins
  • Platelet-Derived Growth Factor
  • Protein Isoforms
  • Proteins
  • Transforming Growth Factor beta1
  • WD repeat containing planar cell polarity effector
  • Wnt Proteins
  • beta Catenin
  • platelet-derived growth factor A