CXXC5 is a transcriptional activator of Flk-1 and mediates bone morphogenic protein-induced endothelial cell differentiation and vessel formation

FASEB J. 2014 Feb;28(2):615-26. doi: 10.1096/fj.13-236216. Epub 2013 Oct 17.


CXXC5 is a member of a small subset of proteins containing CXXC-type zinc-finger domain. Here, we show that CXXC5 is a transcription factor activating Flk-1, a receptor for vascular endothelial growth factor. CXXC5 and Flk-1 were accumulated in nucli and membrane of mouse embryonic stem cells (mESCs), respectively, during their endothelial differentiation. CXXC5 overexpression induced Flk-1 transcription in both endothelium-differentiated mESCs and human umbilical vein endothelial cells (HUVECs). In vitro DNA binding assay showed direct interaction of CXXC5 on the Flk-1 promoter region, and mutation on its DNA-binding motif abolished transcriptional activity. We showed that bone morphorgenetic protein 4 (BMP4) induced CXXC5 transcription in the cells, and inhibitors of BMP signaling suppressed the CXXC5 induction and the consequent Flk-1 induction by BMP4 treatment. CXXC5 knockdown resulted in suppression of BMP4-induced stress fiber formation (56.8 ± 1.3% decrease, P<0.05) and migration (54.6 ± 1.9% decrease, P<0.05) in HUVECs. The in vivo roles of CXXC5 in BMP-signaling-specific vascular development and angiogenesis were shown by specific defect of caudal vein plex vessel formation (57.9 ± 11.8% decrease, P<0.05) in cxxc5 morpholino-injected zebrafish embryos and by suppression of BMP4-induced angiogenesis in subcutaneously injected Matrigel plugs in CXXC5(-/-) mice. Overall, CXXC5 is a transcriptional activator for Flk-1, mediating BMP signaling for differentiation and migration of endothelial cell and vessel formation.

Keywords: HUVECs; caudal vein plex vessel formation; mouse embryonic stem cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiogenesis Inducing Agents / pharmacology
  • Animals
  • Bone Morphogenetic Protein 4 / pharmacology*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Differentiation / drug effects
  • Cell Differentiation / genetics
  • Cell Differentiation / physiology*
  • DNA-Binding Proteins
  • Humans
  • Mice
  • Transcription Factors
  • Vascular Endothelial Growth Factor Receptor-2 / genetics
  • Vascular Endothelial Growth Factor Receptor-2 / metabolism*
  • Zebrafish / genetics
  • Zebrafish / metabolism*


  • Angiogenesis Inducing Agents
  • Bone Morphogenetic Protein 4
  • CXXC5 protein, human
  • Carrier Proteins
  • DNA-Binding Proteins
  • Transcription Factors
  • Vascular Endothelial Growth Factor Receptor-2