Angiogenesis is required for embryogenesis, tumor formation, and wound healing. Signaling by binding of vascular endothelial growth factor (VEGF) to its receptor VEGFR-2 is a major control point for angiogenesis. The magnitude of this signaling pathway is intimately associated with the abundance of VEGFR-2 at the cell surface. Although VEGF-induced endocytosis and degradation control the cell-surface level of VEGFR-2, very little is known about the machinery that governs VEGFR-2 endocytosis and degradation. Epsin is an endocytic adaptor protein that mediates endocytosis of activated receptors. We have generated mutant mice that lack epsin 1 and 2 globally or selectively in endothelial cells. These mutant mice exhibited similar embryonic lethality due to abnormal vascular development typified by increased vessel density and disorganized architecture. VEGFR-2 expression was elevated, reflecting enhanced VEGF function. We hypothesize that epsin-dependent regulation of VEGFR-2 endocytosis and degradation is crucial for VEGF-mediated vascular development and angiogenesis. To test this hypothesis, we will utilize endothelial cell-specific epsin double knockout mice to determine the functions of epsins in regulating angiogenic sprouting, endothelial cell proliferation, and endothelial cell survival. We will engineer tamoxifen inducible endothelial cell-specific epsin double knockout mice to probe the role of epsins in postnatal angiogenesis under physiological and pathological conditions. The in vivo studies will be complemented by in vitro assays of endothelial cell migration, proliferation, tube formation, vessel sprouting, and VEGF-dependent signaling. We will also use biochemical and fluorescent imaging techniques to investigate the interaction of epsins and VEGFR-2 and the role of epsins in VEGF-induced VEGFR-2 endocytosis and degradation. The information gained will help us determine molecular mechanisms by which epsin-mediated endocytosis regulates VEGF signaling and controls vascular development and angiogenesis. These studies should contribute to the application of endocytic components to new therapeutic strategies for cardiovascular diseases and cancer.

Public Health Relevance

New blood vessel formation is critical for both embryogenesis and reparative/ adaptive responses. We will study the role of a novel signaling molecule epsin in the formation of new blood vessels. Our work may lead to better treatments for heart disease that involves new blood vessel formation.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
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Vascular Cell and Molecular Biology Study Section (VCMB)
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Gao, Yunling
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Oklahoma Medical Research Foundation
Oklahoma City
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Dong, Yunzhou; Fernandes, Conrad; Liu, Yanjun et al. (2017) Role of endoplasmic reticulum stress signalling in diabetic endothelial dysfunction and atherosclerosis. Diab Vasc Dis Res 14:14-23
Dong, Yunzhou; Cai, Xue; Wu, Yong et al. (2017) Insights from Genetic Model Systems of Retinal Degeneration: Role of Epsins in Retinal Angiogenesis and VEGFR2 Signaling. J Nat Sci 3:
Song, Kai; Fu, Jianxin; Song, Jianhua et al. (2017) Loss of mucin-type O-glycans impairs the integrity of the glomerular filtration barrier in the mouse kidney. J Biol Chem 292:16491-16497
Song, Kai; Wu, Hao; Rahman, H N Ashiqur et al. (2017) Endothelial epsins as regulators and potential therapeutic targets of tumor angiogenesis. Cell Mol Life Sci 74:393-398
Bergstrom, Kirk; Liu, Xiaowei; Zhao, Yiming et al. (2016) Defective Intestinal Mucin-Type O-Glycosylation Causes Spontaneous Colitis-Associated Cancer in Mice. Gastroenterology 151:152-164.e11
Rahman, H N Ashiqur; Wu, Hao; Dong, Yunzhou et al. (2016) Selective Targeting of a Novel Epsin-VEGFR2 Interaction Promotes VEGF-Mediated Angiogenesis. Circ Res 118:957-969
Dong, Yunzhou; Wu, Hao; Rahman, H N Ashiqur et al. (2015) Motif mimetic of epsin perturbs tumor growth and metastasis. J Clin Invest 125:4349-64
Song, Kai; Herzog, Brett H; Fu, Jianxin et al. (2015) Loss of Core 1-derived O-Glycans Decreases Breast Cancer Development in Mice. J Biol Chem 290:20159-66
Chang, Baojun; Tessneer, Kandice L; McManus, John et al. (2015) Epsin is required for Dishevelled stability and Wnt signalling activation in colon cancer development. Nat Commun 6:6380
Liu, Xiaolei; Pasula, Satish; Song, Hoogeun et al. (2014) Temporal and spatial regulation of epsin abundance and VEGFR3 signaling are required for lymphatic valve formation and function. Sci Signal 7:ra97

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