Thrombospondin (TSP)-1 is an ~420KDa trimeric, multidomain glycoprotein that engages multiple endothelial cell (EC) receptors and elicits multiple EC responses. The zonula adherens (ZA) is a specialized structure that, through the catenins, couples the actin cytoskeleton to the cytoplasmic domain of vascular endothelial (VE)-cadherin, a surface receptor that mediates homophilic EC-EC adhesion. In human pulmonary microvascular endothelia, we have demonstrated that TSP-1 increases tyrosine phosphorylation of the ZA proteins, VE-cadherin, y-catenin and p120ctn, and opens the paracellular pathway. Prior protein tyrosine kinase (PTK) inhibition protects against TSP-1-induced barrier disruption whereas protein tyrosine phosphatase (PTP) inhibition enhances it. We now present evidence that TSP-1 activates the receptor PTKs, ErbB1 and ErbB2, and opens the endothelial paracellular pathway through this activation. Further, PTP(, a receptor PTP that regulates VE-cadherin tyrosine phosphorylation and the endothelial paracellular pathway, counter-regulates EGFR/ErbB2 activation. We propose the following Specific Aims: 1) To define the specific sequence(s) within TSP-1 required to open the tyrosine phosphorylation - responsive paracellular pathway in human pulmonary microvascular endothelia. 2) To elucidate the mechanism(s) through which TSP-1 activates EGFR/erbB2, including a) direct binding of its EGF-like repeats to the ectodomain of EGFR, b) stimulation of EC release of an EGFR ligand, and/or c) activation of another TSP-1 receptor(s) that transactivates EGFR/erbB2. 3) To determine the mechanism(s) through which TSP-1 activation of EGFR/erbB2 is coupled to increased tyrosine phosphorylation of ZA and/or other junctional proteins, ZA reorganization, and/or opening of the endothelial paracellular pathway. 4) To define the counter-regulatory role for PTP( in TSP-1-induced EGFR/ErbB2 activation. Understanding the mechanism(s) through which TSP-1 regulates EC-EC homophilic adhesion and the paracellular pathway has implications for angiogenesis within the context of wound healing, tissue remodeling, and tumor cell survival, as well as the movement of cells, macromolecules, and fluids from the bloodstream into extravascular tissues.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL084223-05
Application #
8008784
Study Section
Respiratory Integrative Biology and Translational Research Study Section (RIBT)
Program Officer
Moore, Timothy M
Project Start
2007-01-01
Project End
2012-12-31
Budget Start
2011-01-01
Budget End
2012-12-31
Support Year
5
Fiscal Year
2011
Total Cost
$370,260
Indirect Cost
Name
University of Maryland Baltimore
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
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Lee, Chunsik; Liu, Anguo; Miranda-Ribera, Alba et al. (2014) NEU1 sialidase regulates the sialylation state of CD31 and disrupts CD31-driven capillary-like tube formation in human lung microvascular endothelia. J Biol Chem 289:9121-35
Lillehoj, Erik P; Hyun, Sang Won; Feng, Chiguang et al. (2014) Human airway epithelia express catalytically active NEU3 sialidase. Am J Physiol Lung Cell Mol Physiol 306:L876-86
Lillehoj, Erik P; Hyun, Sang Won; Feng, Chiguang et al. (2012) NEU1 sialidase expressed in human airway epithelia regulates epidermal growth factor receptor (EGFR) and MUC1 protein signaling. J Biol Chem 287:8214-31
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Hyun, Sang W; Anglin, Ian E; Liu, Anguo et al. (2011) Diverse injurious stimuli reduce protein tyrosine phosphatase-μ expression and enhance epidermal growth factor receptor signaling in human airway epithelia. Exp Lung Res 37:327-43
Liu, Anguo; Mosher, Deane F; Murphy-Ullrich, Joanne E et al. (2009) The counteradhesive proteins, thrombospondin 1 and SPARC/osteonectin, open the tyrosine phosphorylation-responsive paracellular pathway in pulmonary vascular endothelia. Microvasc Res 77:13-20
D'Souza, David R; Salib, Maryann M; Bennett, Jessica et al. (2009) Hyperglycemia regulates RUNX2 activation and cellular wound healing through the aldose reductase polyol pathway. J Biol Chem 284:17947-55

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