Formation of blood-carrying channels at the heart of blood vessels (lumen formation or 'tubulogenesis') is one of the most critical steps during cardiovascular development. To date, the molecular mechanisms underlying this process remain unclear. Understanding and ultimately controlling blood vessel growth are key goals of many clinical approaches, ranging from blocking vessels in tumor angiogenesis to promoting vessels in wound healing. Transcriptional profiling of embryonic endothelial cells (ECs) was carried out to discover factors that regulate blod vesel formation, and identified a GTPase-interacting protein called Rasip1. Rasip1 was found to be expressed specificaly in embryonic ECs, and ablation of Rasip1 in mice blocks embryonic vascular tubulogenesis and blood vessel formation. We showed those Rasip1 complexes with small GTPases and their effectors, to promote Cdc42 and Rac1, and suppress RhoA. Key defects in Rasip1-/- cords (E8.0-8.5) include: loss of angioblast cell polarity and of proper localization of the polarity determinant Par3, as well as disruption of 1integrin-mediated adhesion to ECM and of the cytoskeleton. The main hypothesis is that Rasip1 regulates distinct downstream GTPase signaling pathways, such as Rho, Rac and Cdc42, which regulate distinct cellular processes that coordinate to drive vascular tubulogenesis. This proposal asks how Rasip1-mediated cell polarity, contractility and adhesion influence endothelial tubulogenesis, and dissects pathways downstream of Rasip1 using mouse genetics, in vitro models and biochemistry. For analysis of mouse mutants, simple parameters will be assessed to study lumen formation in E8.0-8.5 mouse dorsal aortae (angioblast morphology and organization, as well as polarity and adhesion markers).
Specific aims are: 1. To examine role of Rasip1-dependent cell polarity and mechanisms of apical/luminal membrane formation during vascular lumen formation (Par3 and Crb3). 2. To identify the cellular outcomes of the different Rasip1-regulated GTPase signaling pathways, Rho, Rac1 and Cdc42, during vascular lumen formation, and assess which pathways can rescue or exacerbate the Rasip1 null lumen failure. 3. To elucidate mechanism of Rasip1-dependent lumen formation via identification of lumen formation 'signaling complex'components. The short-term objective of these studies is to elucidate Rasip1 regulated pathways and further our understanding of cardiovascular development. The long-term objective is to find new molecular targets to block blood vessel growth in disease, such as in growing tumors, by blocking lumen formation. !

Public Health Relevance

Blood vessel growth and function depend on the formation of blood-carrying channels at their core, via a process called 'lumen formation'or 'tubulogenesis'. Here, we investigate a molecule, Rasip1, and its regulation of the activity of small molecular switches called GTPases that control endothelial cell shape and organization during vascular tubulogenesis. The ultimate goal is to find new molecular targets to block blood vessel growth in disease, such as in growing tumors, by blocking lumen formation. !

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL113498-01
Application #
8274559
Study Section
Cardiovascular Differentiation and Development Study Section (CDD)
Program Officer
Schramm, Charlene A
Project Start
2012-04-05
Project End
2016-03-31
Budget Start
2012-04-05
Budget End
2013-03-31
Support Year
1
Fiscal Year
2012
Total Cost
$396,979
Indirect Cost
$146,979
Name
University of Texas Sw Medical Center Dallas
Department
Biochemistry
Type
Schools of Medicine
DUNS #
800771545
City
Dallas
State
TX
Country
United States
Zip Code
75390
Koo, Yeon; Barry, David M; Xu, Ke et al. (2016) Rasip1 is essential to blood vessel stability and angiogenic blood vessel growth. Angiogenesis 19:173-90
Azizoglu, D Berfin; Cleaver, Ondine (2016) Blood vessel crosstalk during organogenesis-focus on pancreas and endothelial cells. Wiley Interdiscip Rev Dev Biol 5:598-617
Barry, David M; Koo, Yeon; Norden, Pieter R et al. (2016) Rasip1-Mediated Rho GTPase Signaling Regulates Blood Vessel Tubulogenesis via Nonmuscle Myosin II. Circ Res 119:810-26
Azizoglu, D Berfin; Chong, Diana C; Villasenor, Alethia et al. (2016) Vascular development in the vertebrate pancreas. Dev Biol 420:67-78
Meadows, Stryder M; Cleaver, Ondine (2015) Annexin A3 Regulates Early Blood Vessel Formation. PLoS One 10:e0132580
Barry, David M; Xu, Ke; Meadows, Stryder M et al. (2015) Cdc42 is required for cytoskeletal support of endothelial cell adhesion during blood vessel formation in mice. Development 142:3058-70
Dunworth, William P; Cardona-Costa, Jose; Bozkulak, Esra Cagavi et al. (2014) Bone morphogenetic protein 2 signaling negatively modulates lymphatic development in vertebrate embryos. Circ Res 114:56-66
Lee, Eunmyong; Koo, Yeon; Ng, Aylwin et al. (2014) Autophagy is essential for cardiac morphogenesis during vertebrate development. Autophagy 10:572-87
Davis, George E; Cleaver, Ondine B (2014) Outside in: inversion of cell polarity controls epithelial lumen formation. Dev Cell 31:140-2
Dellinger, Michael T; Meadows, Stryder M; Wynne, Katherine et al. (2013) Vascular endothelial growth factor receptor-2 promotes the development of the lymphatic vasculature. PLoS One 8:e74686

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