The Foxc2 Transcription Factor Regulates Angiogenesis via Induction of Integrin β3 Expression

Abstract

Forkhead transcription factor Foxc2 is an essential regulator of the cardiovascular system in development and disease. However, the cellular and molecular functions of Foxc2 in vascular endothelial cells are still not fully understood. Here, through gene expression profiling in endothelial cells, we identified molecules associated with cell-extracellular matrix interactions, integrin ␤3 (Itgb3), integrin ␤5 (Itgb5), and fibronectin, as downstream targets of Foxc2. We found that Itgb3 expression is directly regulated by Foxc2 through multiple Forkhead-binding elements within two high homology regions in the Itgb3 promoter. Because Itgb3 is known to regulate angiogenesis, we further tested whether Foxc2 is directly involved in angiogenesis by regulating Itgb3 expression by in vitro experiments. Overexpression of Foxc2 significantly enhanced endothelial cell migration and adhesion, whereas this effect was strongly inhibited by Itgb3 neutralization antibody. In accordance with these results, pulmonary microvascular endothelial cells isolated from Foxc2 heterozygous mutant mice showed a marked reduction in Itgb3 expression and cell migration. Finally, ex vivo aortic ring assay to test the sprouting and microvessel formation revealed enhanced microvessel outgrowth by Foxc2 overexpression. Conversely, microvessel outgrowth from aortas of Foxc2 heterozygous mutant mice was reduced. Taken together, these results suggest that Foxc2 directly induces Itgb3 expression and regulates angiogenesis by Itgb3-mediated endothelial cell adhesion and migration.

JunB regulates angiogenesis and neurovascular parallel alignment in mouse embryonic skin

“…Among candidate molecules, the integrin subunit β3 (encoded by ITGB3) was previously shown to promote angiogenesis (Davis and Senger, 2005;Hayashi et al, 2008). In agreement, the present analyses showed a significant upregulation of ITGB3 in JunBoverexpressing ECs (Fig.…”

“…1G), potentially offering synergenic contributions to arterial differentiation and angiogenesis. Furthermore, ITGB3, which encodes the β3 subunit of integrin αVβ3 and is known to be involved in angiogenesis (Davis and Senger, 2005;Hayashi et al, 2008), was also significantly upregulated (Fig. 1G).…”

FOXC2 controls formation and maturation of lymphatic collecting vessels through cooperation with NFATc1

“…Previous studies suggested several FOXC2 target genes in blood vascular endothelium based on computational analysis of proximal promoters (Hayashi and Kume, 2008a,b;Hayashi et al, 2008). In this report, we have studied the association of FOXC2 across the entire genome, and we show that the vast majority of FOXC2-binding sites are located in the intergenic and intronic regions, arguing that FOXC2 acts primarily via distal enhancers as previously observed for estrogen-related receptor  and FOXa1 (Carroll et al, 2005;Lupien et al, 2008).…”

FOXF2 suppresses the FOXC2-mediated epithelial–mesenchymal transition and multidrug resistance of basal-like breast cancer

“…Fibronectin-integrin interactions play an important role in cell adhesion, migration and invasion by activating integrin-linked signaling [24]. Hayashi et al [25] reported that FOXC2 induces the expression of the integrin β3 subunit by directly binding to the ITGB3 promoter, thereby regulating integrin β3-mediated endothelial cell adhesion and migration. In our study, we found that FOXC2 mediates FOXF2-regulated integrin β3 expression and cellfibronectin adhesion in BLBC cells, suggesting that integrin β3 is regulated by the FOXF2/FOXC2 pathway and contributes to the acquisition of the aggressive properties of BLBC cells.…”