Arteries and veins are anatomically distinct within the adult circulatory system, and it was previously thought that the differentiated identities of arterial and venous endothelial cells arose in response to hemodynamic forces such as blood pressure and the direction of blood flow. However, recent evidence suggests that the specification/differentiation of arteries and veins is governed by genetic mechanisms before the active onset of circulation. This event occurs before remodeling of blood vessels, and impaired specification/differentiation of arteries and veins leads to failure to remodel blood vessels. Although it has been shown that several signaling systems such as the VEGF, Notch, and ephrin signaling pathways are involved in this process, molecular mechanisms of how transcription factors function to regulate expression of such genes remain to be elucidated. We have previously shown that the two genes encoding closely related Fox transcription factors, Foxc1 and Foxc2, are expressed in overlapping populations of cells contributing to the endothelial and mesenchymal cells of the blood vessels. Embryos lacking either Foxc1 or Foxc2, and most compound heterozygotes, die pre or perinatally with similar abnormal phenotypes, including defects in the cardiovascular system. Compound Foxc1; Foxc2 homozygotes die earlier and with much more severe defects than single homozygotes alone. Most importantly, compound homozygotes have arteriovenous malformations and the failure of blood vessels to remodel, and in the endothelial cells of compound homozygotes Notch signaling genes and ephrinB2 are downregulated. These data lead to the central hypothesis that Foxc1 and Foxc2 play dose-dependent, interactive roles in the process of arterial-venous cell fate determination/differentiation. One of the goals of this grant is to test whether Foxc proteins act downstream of VEGF signaling to regulate arterial-venous identity (Aim 1). The proposed hypothesis will be tested by (a) analyzing conditional compound mutants of Foxc1 and Foxc2 in endothelial cells crossed with Tie2-Cre mice and (b) rescue experiments in which Tie2-Foxc transgenic mice are crossed with compound Foxcl; Foxc2 mutants (Aims 2). Finally, direct target gene(s) regulated by Foxc1 and Foxc2 in the process of specification/differentiation of arteries and veins will be identified (Aim 3). Elucidating the molecular mechanisms of how Foxcl/c2 function during vascular development will significantly contribute to our knowledge of how genes cooperate to control mammalian cardiovascular development and will lead to a better understanding of human congenital defects.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL074121-01A1
Application #
6776121
Study Section
Experimental Cardiovascular Sciences Study Section (ECS)
Program Officer
Schramm, Charlene A
Project Start
2004-04-01
Project End
2008-02-28
Budget Start
2004-04-01
Budget End
2005-02-28
Support Year
1
Fiscal Year
2004
Total Cost
$339,750
Indirect Cost
Name
Vanderbilt University Medical Center
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
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Liu, Wenzhong; Schultz, Kathryn M; Zhang, Kevin et al. (2014) In vivo corneal neovascularization imaging by optical-resolution photoacoustic microscopy. Photoacoustics 2:81-86
Fatima, Anees; Culver, Austin; Culver, Ford et al. (2014) Murine Notch1 is required for lymphatic vascular morphogenesis during development. Dev Dyn 243:957-64
Koo, Hyun-Young; Kume, Tsutomu (2013) FoxC1-dependent regulation of vascular endothelial growth factor signaling in corneal avascularity. Trends Cardiovasc Med 23:1-4
Seo, Seungwoon; Singh, Hardeep P; Lacal, Pedro M et al. (2012) Forkhead box transcription factor FoxC1 preserves corneal transparency by regulating vascular growth. Proc Natl Acad Sci U S A 109:2015-20
Sasman, Amy; Nassano-Miller, Carey; Shim, Kyoo Seok et al. (2012) Generation of conditional alleles for Foxc1 and Foxc2 in mice. Genesis 50:766-74
Kume, Tsutomu (2012) Ligand-dependent Notch signaling in vascular formation. Adv Exp Med Biol 727:210-22
Zhang, Jianghui; Fukuhara, Shigetomo; Sako, Keisuke et al. (2011) Angiopoietin-1/Tie2 signal augments basal Notch signal controlling vascular quiescence by inducing delta-like 4 expression through AKT-mediated activation of beta-catenin. J Biol Chem 286:8055-66
Kume, Tsutomu (2010) Specification of arterial, venous, and lymphatic endothelial cells during embryonic development. Histol Histopathol 25:637-46
Sano, Hideto; Leboeuf, Jared P; Novitskiy, Sergey V et al. (2010) The Foxc2 transcription factor regulates tumor angiogenesis. Biochem Biophys Res Commun 392:201-6

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