EGFL7 is expressed in bone microenvironment and promotes angiogenesis via ERK, STAT3, and integrin signaling cascades

Shek Man Chim, Vincent Kuek, Siu To Chow, Bay Sie Lim, Jennifer Tickner, Jinmin Zhao, Rosa Chung, Yu Wen Su, Ge ZHANG, Wendy Erber, Cory J. Xian, Vicki Rosen*, Jiake Xu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)

Abstract

Angiogenesis plays a pivotal role in bone formation, remodeling, and fracture healing. The regulation of angiogenesis in the bone microenvironment is highly complex and orchestrated by intercellular communication between bone cells and endothelial cells. Here, we report that EGF-like domain 7 (EGFL7), a member of the epidermal growth factor (EGF) repeat protein superfamily is expressed in both the osteoclast and osteoblast lineages, and promotes endothelial cell activities. Addition of exogenous recombinant EGFL7 potentiates SVEC (simian virus 40-transformed mouse microvascular endothelial cell line) cell migration and tube-like structure formation in vitro. Moreover, recombinant EGFL7 promotes angiogenesis featuring web-like structures in ex vivo fetal mouse metatarsal angiogenesis assay. We show that recombinant EGFL7 induces phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), signal transducer and activator of transcription 3 (STAT3), and focal adhesion kinase (FAK) in SVEC cells. Inhibition of ERK1/2 and STAT3 signaling impairs EGFL7-induced endothelial cell migration, and angiogenesis in fetal mouse metatarsal explants. Bioinformatic analyses indicate that EGFL7 contains a conserved RGD/QGD motif and EGFL7-induced endothelial cell migration is significantly reduced in the presence of RGD peptides. Moreover, EGFL7 gene expression is significantly upregulated during growth plate injury repair. Together, these results demonstrate that EGFL7 expressed by bone cells regulates endothelial cell activities through integrin-mediated signaling. This study highlights the important role that EGFL7, like EGFL6, expressed in bone microenvironment plays in the regulation of angiogenesis in bone.

Original languageEnglish
Pages (from-to)82-94
Number of pages13
JournalJournal of Cellular Physiology
Volume230
Issue number1
DOIs
Publication statusPublished - Jan 2015

Scopus Subject Areas

  • Physiology
  • Clinical Biochemistry
  • Cell Biology

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