2008 — 2013 |
Jin, Suk-Won |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Endothelial Lineage Specification and Differentiation in Vertebrate Embryos @ University of North Carolina Chapel Hill
[unreadable] DESCRIPTION (provided by applicant): Recent advances in cell culture studies provide invaluable insights on how the endothelial lineage is modulated by diverse signaling pathways. However, the cellular and molecular mechanisms that regulate the initial specification of endothelial lineage within developing embryos are largely unknown. To delineate the developmental origin of the endothelial lineage, we previously generated a laser assisted single-cell resolution fate map in the most ventral region of zebrafish gastrula that provided the first detailed distribution pattern of the hemangioblast, a hypothetical common precursor for both endothelial and hematopoietic lineages. Additionally, in our previous study, we found that hemangioblasts only produce a subset of the endothelial lineage, while the majority originates from endothelial specific progenitors, indicating the heterogeneous developmental origin of endothelial lineage. Our recent observation that avascular mutant embryos recover from their initial lack of endothelial cells later in development, further supports this idea, and suggests that the progenitors of the endothelial lineage consist of spatially and temporally distinct subpopulations. In this proposal, by using a multifaceted approach, we plan to delineate the heterogeneity of endothelial progenitors, and elucidate how distinct subpopulations of endothelial progenitors respond differently to Wnt signaling, which, based on our preliminary data, appears to be a key modulator of endothelial lineage specification. Three specific aims are designed to achieve these goals. First, we will expand our single-cell resolution fate map analyses to test whether hemangioblasts exist in other areas of the gastrula. This approach will also determine the embryo-wide distribution patterns of progenitors with endothelial potential, and will allow us to identify subpopulations of endothelial progenitors with distinct developmental potentials. In the second aim, we plan to define the cellular origin of endothelial cells involved in the vascular recovery of avascular mutant embryos. The analyses on two of previously isolated avascular zebrafish mutants will identify subpopulations of progenitors that generate endothelial lineages in a temporally distinctive manner. Lastly, we will examine whether subpopulations of endothelial progenitors respond differently to Wnt signaling by using transgenic lines that are capable of manipulating the time and place of Wnt activity. Understanding the developmental heterogeneity of the endothelial lineage will provide invaluable insights on how endothelial lineage is established during development. In addition, the proposed research will enhance our knowledge on how distinct cell types emerge from pluripotent progenitors during development. Furthermore, the proposed research may provide essential groundwork for the therapeutic application of pluripotent progenitors with the ability to ameliorate clinical conditions affecting the circulatory system in humans. PUBLIC HEALTH RELEVANCE. The proposed research aims to understand how endothelial cells emerge during development from progenitors. Information acquired from the proposed research will enhance our current knowledge on the mechanisms that regulate the differentiation of pluripotent progenitors (for example, stem cells) into specific cell types. Furthermore, it will also help us to understand the etiology of many vascular diseases and design a better way of using pluripotent progenitors for the therapeutic purposes. [unreadable] [unreadable] [unreadable]
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1 |
2013 — 2016 |
Jin, Suk-Won |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Bone Morphogenic Protein Signaling in Lymphatic Endothelial Cells
DESCRIPTION (provided by applicant): Lymphatic vessels are essential to maintain homeostasis of individuals. Although several factors that promote lymphatic development have been identified, those that negatively regulate lymphatic development remain currently unknown. We have recently demonstrated that Bone Morphogenetic Protein 2 (BMP2) signaling functions as a context dependent pro-angiogenic cue in zebrafish, promoting angiogenesis from venous endothelial cells without affecting arterial endothelial cells. Interestingly, BMP2 signalin exerts its pro-angiogenic effects on venous endothelial cells at the expense of lymphatic endothelial cells (LECs). In embryos with an elevated level of BMP2 signaling, lymphatic endothelial cells fail to emerge. BMP2 signaling appears to inhibit the onset of prox1 expression while promoting the expression of miR-181a and miR-31, both of which are known to negatively regulate prox1. Moreover, BMP2 signaling attenuates the cellular response to VEGF-C signaling in LECs, and functionally interacts with the main VEGF-C receptor, Vegfr3/Ftl4, therefore, is likely to attenuate Vegf-C signaling. Based on our preliminary data, we hypothesize that BMP signaling negatively regulates lymphatic development. To fully understand the molecular and cellular mechanisms that enable the function of BMP2 signaling, we propose two specific aims to investigate, using zebrafish and cell culture models. We will determine molecular and cellular mechanisms that mediate BMP function in LECs and investigate how BMP2 signaling impacts lymphatic development (Aim 1), and delineate how BMP2 signaling modulates subsequent lymphatic patterning (Aim 2). We will accomplish these goals using innovative approaches and models. We anticipate that the knowledge of how BMP2 effects lymphatic vessels gained through this work will be significant both in increasing our basic understanding of how lymphatic development is coordinated and provide a theoretical background in developing therapeutic interventions for lymphedema and other dysfunctions of lymphatic vessels.
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0.97 |