Fibroblast growth factor-1-induced ERK1/2 signaling reciprocally regulates proliferation and smooth muscle cell differentiation of ligament-derived endothelial progenitor cell-like cells

Int J Mol Med. 2012 Mar;29(3):357-64. doi: 10.3892/ijmm.2011.847. Epub 2011 Nov 22.


The periodontal ligament (PDL) is a fibrous connective tissue located between the tooth root and the alveolar bone. We previously demonstrated that a single cell-derived culture of primarily cultured PDL fibroblasts has the potential to construct an endothelial cell (EC) marker-positive blood vessel-like structure, suggesting that the fibroblastic lineage cells in ligament tissue could act as the endothelial progenitor cells (EPCs), which regenerate to construct a vascular system around the damaged ligament tissue. Moreover, we showed that EPC-like fibroblasts expressed not only EC markers but also smooth muscle cell (SMC) markers. Generally, an interaction between ECs and SMCs regulates blood vessel development and remodeling, and is required for the formation of a mature and functional vascular network. However, the mechanism underlying the SMC differentiation of the ligament-derived EPC-like fibroblasts remains to be clarified. In this study, we showed that suppression of fibroblast growth factor 1 (FGF-1)-induced extracellular signal-regulated kinase 1/2 (ERK1/2) signaling with the MAPK/ERK kinase (MEK) inhibitor U0126 completely abolished the FGF-1-induced proliferation of the ligament-derived EPC-like fibroblasts. In addition, U0126 treatment of FGF-1-stimulated ligament-derived EPC-like fibroblasts significantly induced the SMC differentiation of the cells. Thus, FGF-1-induced ERK1/2 signaling not only promoted the proliferation of the ligament-derived EPC-like fibroblasts, but also suppressed the SMC differentiation of the cells, suggesting that FGF-1 controls the construction of a vascular network around the ligament tissue by regulating the proliferation and SMC differentiation of the EPC-like cells through ERK-mediated signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Cell Differentiation / drug effects
  • Cell Proliferation / drug effects
  • Cells, Cultured
  • Endothelial Cells / cytology*
  • Endothelial Cells / drug effects
  • Endothelial Cells / enzymology
  • Extracellular Signal-Regulated MAP Kinases / metabolism*
  • Fibroblast Growth Factor 1 / pharmacology*
  • Fibroblasts / cytology
  • Fibroblasts / drug effects
  • MAP Kinase Signaling System / drug effects*
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Myocytes, Smooth Muscle / cytology*
  • Myocytes, Smooth Muscle / drug effects
  • Myocytes, Smooth Muscle / enzymology
  • Periodontal Ligament / cytology*
  • Phosphorylation / drug effects
  • Protein Multimerization / drug effects
  • Rats
  • Stem Cells / cytology*
  • Stem Cells / drug effects
  • Stem Cells / enzymology


  • Actins
  • Fibroblast Growth Factor 1
  • Extracellular Signal-Regulated MAP Kinases
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3