Dysfunction of the vascular endothelium contributes to most cardiovascular, circulatory, and blood diseases. This is not surprising, as the endothelium is the central regulator of hemostasis, vascular development, angiogenesis, vasomotor tone, and the response to vascular injury and inflammation. We have used several complementary approaches during the past funding cycle taking advantage of our longstanding interest in endothelial cell differentiation and gene expression programs to fill in the gaps in our understanding of how endothelial cell destiny and phenotypic diversity are determined. Some of our most exciting findings during the previous funding cycle came from the results of using global gene expression analysis of differentiating endothelial cells to identify candidate genes that are responsible for vascular development. Through this approach, we established a comprehensive list of candidate genes associated with the development of the vascular system during embryonic stem cell differentiation in vivo. Many of the genes we identified in this study were predictable: growth factors, cell surface markers, transcription factors and members of several signal transduction pathways already known to be associated with vasculogenesis. However, we also discovered some new players, including members of the bone morphogenetic protein (BMP) and Wnt signaling pathways. In addition, we identified and cloned the novel endothelial cell precursor-derived protein called BMPER, which has become a major focus of the Specific Aims proposed for our next funding cycle. In this funding cycle, we will explore in more detail the molecular roles of these proteins in modulating endothelial cell phenotypes, with a focus on BMP signaling pathways in the vasculature.
The aims of the proposal are to (1) understand the diversity of molecular effects of BMPER in endothelial cells;(2) characterize the diversity of cellular effects of BMPER in endothelial cells;and (3) delineate the role of BMPER in regulation of vascular angiogenic signaling events and inflammation. The scope of this proposal is intended to address relevant biological and physiological questions using state of the art molecular biology techniques. Knowledge gained from this proposal should provide crucial information about endothelial cell development from multipotent precursors, blood vessel formation in health and disease, and endothelial cell-type specific gene expression. In addition, mechanisms for targeted gene delivery to endothelial cells and for disruption and angiogenesis in its pathologic forms may be revealed.

Public Health Relevance

The endothelium plays a critical role in vascular development and pattern formation during embryogenesis, and endothelial cells regulate vessel wall homeostasis, tissue response to ischemia, and vascular regeneration through their effects on vasomotor function and inflammation, angiogenesis, and progenitor cell dynamics. Our overall goal is to determine the events that contribute to vascular differentiation and morphogenesis, with the anticipation that these same processes are recapitulated in angiogenesis-dependent events in the adult.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-CVS-P (02))
Program Officer
Gao, Yunling
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of North Carolina Chapel Hill
Internal Medicine/Medicine
Schools of Medicine
Chapel Hill
United States
Zip Code
Pi, Xinchun; Xie, Liang; Patterson, Cam (2018) Emerging Roles of Vascular Endothelium in Metabolic Homeostasis. Circ Res 123:477-494
Angelini, Aude; Pi, Xinchun; Xie, Liang (2017) Dioxygen and Metabolism; Dangerous Liaisons in Cardiac Function and Disease. Front Physiol 8:1044
Lockyer, Pamela; Mao, Hua; Fan, Qiying et al. (2017) LRP1-Dependent BMPER Signaling Regulates Lipopolysaccharide-Induced Vascular Inflammation. Arterioscler Thromb Vasc Biol 37:1524-1535
Mao, Hua; Xie, Liang; Pi, Xinchun (2017) Low-Density Lipoprotein Receptor-Related Protein-1 Signaling in Angiogenesis. Front Cardiovasc Med 4:34
Mao, Hua; Lockyer, Pamela; Li, Luge et al. (2017) Endothelial LRP1 regulates metabolic responses by acting as a co-activator of PPAR?. Nat Commun 8:14960
Mao, Hua; Lockyer, Pamela; Townley-Tilson, W H Davin et al. (2016) LRP1 Regulates Retinal Angiogenesis by Inhibiting PARP-1 Activity and Endothelial Cell Proliferation. Arterioscler Thromb Vasc Biol 36:350-60
Dyer, Laura; Lockyer, Pamela; Wu, Yaxu et al. (2015) BMPER Promotes Epithelial-Mesenchymal Transition in the Developing Cardiac Cushions. PLoS One 10:e0139209
Townley-Tilson, W H Davin; Pi, Xinchun; Xie, Liang (2015) The Role of Oxygen Sensors, Hydroxylases, and HIF in Cardiac Function and Disease. Oxid Med Cell Longev 2015:676893
Xie, Liang; Pi, Xinchun; Wang, Zhongjing et al. (2015) Depletion of PHD3 protects heart from ischemia/reperfusion injury by inhibiting cardiomyocyte apoptosis. J Mol Cell Cardiol 80:156-65
Xie, Liang; Pi, Xinchun; Townley-Tilson, W H Davin et al. (2015) PHD2/3-dependent hydroxylation tunes cardiac response to ?-adrenergic stress via phospholamban. J Clin Invest 125:2759-71

Showing the most recent 10 out of 78 publications