In this renewal proposal, we continue our work demonstrating the critical functional role of pericyte and endothelial cell (EC)-derived proteinase inhibitors to control the process of endothelial tube stabilization in 3D extracellular matrix environments. Our overall hypothesis is that the proteinase inhibitors, TIMP-3 and TIMP-2, possess stabilizing properties due to their ability to suppress both promorphogenic and proregression stimuli which are necessary for tube stabilization. During this last funding period, we have made essential progress in demonstrating the ability of pericytes to stabilize EC-lined tubes and the role of TIMPs during this process, have developed novel EC-pericyte tube coculture models to identify molecular requirements for these events, and have identified critical EC targets of TIMP-3 and TIMP-2 such as MT1-MMP, MMP-1, MMP-10 and ADAM- 15 which mediate their influence. In addition, we have made significant advances in our ability to;analyze gene expression and function in ECs versus pericytes to identify the molecular requirements for this process;analyze the influence of extracellular matrix remodeling changes such as identifying a requirement for EC- pericyte interactions to catalyze vascular basement membrane matrix assembly;identify mechanisms whereby pericytes are recruited to EC-lined tubes through PDGF-BB and HB-EGF mediated signaling;and determine how critical growth factors such as TGF-beta affect this process. We propose three specific aims which are;
Specific Aim #1 : To determine the molecular mechanisms by which pericytes are able to catalyze endothelial basement membrane matrix assembly to facilitate vascular stabilization.
Specific Aim #2 : To define the mechanisms controlling how pericytes are specifically recruited to endothelial cell-lined tubes and how they dynamically scan the endothelial basal surface through migratory events to regulate tube stabilization.
Specific Aim #3 : To define how pericyte recruitment to developing vascular tubes leads to stabilization through attenuation of regression stimuli mediated by the ubiquitous cytokine, TGF-beta.

Public Health Relevance

This work focuses on the ability of pericytes, a cell type surrounding small blood vessels, to support the integrity of these cell-lined tube structures. These support cells produce a series of proteins that facilitate this support mechanism. A basic understanding of the mechanisms underlying how blood vessels form and become stabilized is critical in efforts to stimulate or inhibit the process in the context of various human diseases such as cardiovascular disease, diabetes or cancer.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
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Study Section
Cardiovascular Differentiation and Development Study Section (CDD)
Program Officer
Gao, Yunling
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University of Missouri-Columbia
Schools of Medicine
United States
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Davis, George E; Kim, Dae Joong; Meng, Chun-Xia et al. (2013) Control of vascular tube morphogenesis and maturation in 3D extracellular matrices by endothelial cells and pericytes. Methods Mol Biol 1066:17-28
Stratman, Amber N; Davis, George E (2012) Endothelial cell-pericyte interactions stimulate basement membrane matrix assembly: influence on vascular tube remodeling, maturation, and stabilization. Microsc Microanal 18:68-80
Sacharidou, Anastasia; Stratman, Amber N; Davis, George E (2012) Molecular mechanisms controlling vascular lumen formation in three-dimensional extracellular matrices. Cells Tissues Organs 195:122-43
Davis, George E (2011) Angiogenesis and Proteinases: Influence on Vascular Morphogenesis, Stabilization and Regression. Drug Discov Today Dis Models 8:13-20
Senger, Donald R; Davis, George E (2011) Angiogenesis. Cold Spring Harb Perspect Biol 3:a005090
Stratman, Amber N; Davis, Michael J; Davis, George E (2011) VEGF and FGF prime vascular tube morphogenesis and sprouting directed by hematopoietic stem cell cytokines. Blood 117:3709-19
Davis, George E (2010) Matricryptic sites control tissue injury responses in the cardiovascular system: relationships to pattern recognition receptor regulated events. J Mol Cell Cardiol 48:454-60
Sacharidou, Anastasia; Koh, Wonshill; Stratman, Amber N et al. (2010) Endothelial lumen signaling complexes control 3D matrix-specific tubulogenesis through interdependent Cdc42- and MT1-MMP-mediated events. Blood 115:5259-69
Davis, George E (2010) The development of the vasculature and its extracellular matrix: a gradual process defined by sequential cellular and matrix remodeling events. Am J Physiol Heart Circ Physiol 299:H245-7
Stratman, Amber N; Malotte, Kristine M; Mahan, Rachel D et al. (2009) Pericyte recruitment during vasculogenic tube assembly stimulates endothelial basement membrane matrix formation. Blood 114:5091-101

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