Two distinct Flk-1+ mesoderm, hemangiogenic and cardiogenic, establish the functional circulatory system. We recently made progress in further identifying Flk-1+ hemangiogenic and cardiogenic mesoderm by the PDGFR1 expression. Specifically, while Flk-1+PDGFR1- hemangiogenic mesoderm can generate hematopoietic and endothelial cells, Flk-1+PDGFR1+ cardiogenic mesoderm can generate endothelial, smooth muscle cells and cardiomyocytes. However, our understanding of how the Flk-1+ mesoderm is specified is currently limiting. Intriguingly, there seems to be an antagonistic relationship between hematopoietic/vascular and cardiac outcome. Our preliminary studies suggest that we can skew the Flk-1+ mesoderm outcome by temporally modulating expression of the hemangiogenic transcription factors. Specifically, when ER71, GATA2 and Scl were temporally co-expressed during the mesoderm formation and patterning stage, only the Flk-1+PDGFR1- hemangiogenic mesoderm was formed. At the same time, no Flk-1+PDGFR1+ cardiogenic mesoderm was formed. Further characterization of the ER71, GATA2, and Scl mediated combinatorial molecular function would provide insights into the mechanisms by which hemangioblast lineage commitment occurs.
In aim 1, we will test the hypothesis that hemangiogenic mesoderm specification occurs at the expense of cardiogenic mesoderm in pluripotent stem cells and developing embryos. The hematopoietic, endothelial cell and cardiogenic potential of inducible ER71- GATA2-Scl pluripotent stem cells and embryos will be fully determined.
In aim 2, we will test the hypothesis that hemangioblast formation requires ER71, GATA2 and Scl functional interaction, which can be elucidated by characterizing their downstream gene regulatory networks.
In aim 3, we will test the hypothesis that pluripotent stem derived hemangioblasts can generate functional hematopoietic and endothelial cells in vivo. We will determine the full in vivo hematopoietic and endothelial cell potential of induced hemangioblasts. Successful completion of the proposed studies will have impact on both basic and applied science. Ultimately, we will have a deeper understanding of how the hematopoietic system is established during embryogenesis. This topic is most fundamental to the developmental biology of hematopoietic, vascular and cardiovascular fields. We envision that "PURE" hemangioblasts can be obtained from any pluripotent stem cells by "temporally" modulating ER71, GATA2 and Scl expression. Thus, positive outcome from the current proposed studies would be directly applicable to regenerative medicine utilizing pluripotent stem cells in the future.

Public Health Relevance

This grant proposal is to understand how blood and blood vessels are established in the developing mouse embryo. This goal will be achieved by characterizing embryonic stem cells and transgenic mice co-expressing developmentally critical master genes that regulate blood and blood vessel development. The outcome of this study is highly relevant to basic research and regenerative medicine.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL055337-17
Application #
8399072
Study Section
Special Emphasis Panel (ZRG1-VH-F (02))
Program Officer
Thomas, John
Project Start
1996-08-01
Project End
2015-11-30
Budget Start
2012-12-01
Budget End
2013-11-30
Support Year
17
Fiscal Year
2013
Total Cost
$361,760
Indirect Cost
$123,760
Name
Washington University
Department
Pathology
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Park, Changwon; Lee, Tae-Jin; Bhang, Suk Ho et al. (2016) Injury-Mediated Vascular Regeneration Requires Endothelial ER71/ETV2. Arterioscler Thromb Vasc Biol 36:86-96
Lohmann, Felix; Dangeti, Mohan; Soni, Shefali et al. (2015) The DEK Oncoprotein Is a Critical Component of the EKLF/KLF1 Enhancer in Erythroid Cells. Mol Cell Biol 35:3726-38
Liu, Fang; Li, Daofeng; Yu, Yik Yeung Lawrence et al. (2015) Induction of hematopoietic and endothelial cell program orchestrated by ETS transcription factor ER71/ETV2. EMBO Rep 16:654-69
Oladipupo, Sunday S; Smith, Craig; Santeford, Andrea et al. (2014) Endothelial cell FGF signaling is required for injury response but not for vascular homeostasis. Proc Natl Acad Sci U S A 111:13379-84
Liu, Fang; Bhang, Suk Ho; Arentson, Elizabeth et al. (2013) Enhanced hemangioblast generation and improved vascular repair and regeneration from embryonic stem cells by defined transcription factors. Stem Cell Reports 1:166-82
Oduro Jr, Kwadwo A; Liu, Fang; Tan, Qing et al. (2012) Myeloid skewing in murine autoimmune arthritis occurs in hematopoietic stem and primitive progenitor cells. Blood 120:2203-13
Zou, Wei; Deselm, Carl J; Broekelmann, Thomas J et al. (2012) Paxillin contracts the osteoclast cytoskeleton. J Bone Miner Res 27:2490-500
Shim, Min Suk; Bhang, Suk Ho; Yoon, Kyunghwan et al. (2012) A bioreducible polymer for efficient delivery of Fas-silencing siRNA into stem cell spheroids and enhanced therapeutic angiogenesis. Angew Chem Int Ed Engl 51:11899-903
Liu, Fang; Kang, Inyoung; Park, Changwon et al. (2012) ER71 specifies Flk-1+ hemangiogenic mesoderm by inhibiting cardiac mesoderm and Wnt signaling. Blood 119:3295-305
Ishitobi, Hiroyuki; Wakamatsu, Asami; Liu, Fang et al. (2011) Molecular basis for Flk1 expression in hemato-cardiovascular progenitors in the mouse. Development 138:5357-68

Showing the most recent 10 out of 16 publications