Gap junction communication mediates transforming growth factor-beta activation and endothelial-induced mural cell differentiation

Circ Res. 2003 Sep 5;93(5):429-37. doi: 10.1161/01.RES.0000091259.84556.D5. Epub 2003 Aug 14.


During blood vessel assembly, endothelial cells recruit mesenchymal progenitors and induce their differentiation into mural cells via contact-dependent transforming growth factor-beta (TGF-beta) activation. We investigated whether gap junction channels are formed between endothelial cells and recruited mesenchymal progenitors and whether intercellular communication is necessary for endothelial-induced mural cell differentiation. Mesenchymal progenitors from Cx43-/- murine embryos and Cx43+/+ littermates were cocultured with prelabeled endothelial cells. Intracellular dye injection and dual whole-cell voltage clamp revealed that endothelial cells formed gap junction channels with Cx43+/+ but not Cx43-/- progenitors. In coculture with endothelial cells, Cx43-/- progenitors did not undergo mural cell differentiation as did Cx43+/+ cells. Stable reexpression of Cx43 in Cx43-/- cells (reCx43) restored their ability to form gap junctions with endothelial cells and undergo endothelial-induced mural cell differentiation. Cocultures of endothelial cells and either Cx43+/+ or reCx43 mesenchymal cells produced activated TGF-beta; endothelial-Cx43-/- cocultures did not. However, Cx43-/- cells did produce latent TGF-beta and undergo mural cell differentiation in response to exogenous TGF-beta1. These studies indicate that gap junction communication between endothelial and mesenchymal cells mediates TGF-beta activation and subsequent mural cell differentiation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cattle
  • Cell Communication / physiology
  • Cell Differentiation / physiology
  • Cells, Cultured
  • Coculture Techniques
  • Connexin 43 / genetics
  • Connexin 43 / metabolism
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / metabolism*
  • Fluorescent Dyes / administration & dosage
  • Fluorescent Dyes / metabolism
  • Gap Junctions / physiology*
  • Gene Expression
  • Immunohistochemistry
  • Isoquinolines / administration & dosage
  • Isoquinolines / metabolism
  • Membrane Potentials / physiology
  • Mesoderm / chemistry
  • Mesoderm / cytology
  • Mesoderm / metabolism*
  • Mice
  • Mice, Knockout
  • Microinjections
  • Patch-Clamp Techniques
  • Transforming Growth Factor beta / metabolism*


  • Connexin 43
  • Fluorescent Dyes
  • Isoquinolines
  • Transforming Growth Factor beta
  • lucifer yellow