Our long-term goal is to understand how the hematopoietic system is established in the developing embryo. Our studies of in vitro differentiated embryonic stem (ES) cells indicate that the hematopoietic system is established via distinct, sequentially generated Flk-1 and SCL-expressing cells. Flk-I+SCL - cells first arise in developing embryoid bodies (EBs, in vitro differentiated progeny of ES cells). The Scl gene is turned on within Flk-1 + SCL- cells to give rise to Flk-1 + SCL + cells. The hemangioblast cell population, a common progenitor of hematopoietic and endothelial cells, was enriched within these cells. Within Flk-I+SCL + cells, Flk-1 is down regulated to finally generate Flk-I-SCL + hematopoietic progenitors. A serum free in vitro differentiation model of ES cells has identified that bone morphogenetic protein (BMP) -4 is critical in the generation of Flk-1 + and SCL + cells. Many studies implicate the importance of BMP-4 in hematopoietic development. However, none of the studies examined the precise developmental stage in which the BMP-4 functions. Our proposal is to further characterize molecular mechanisms controlling Flk-1 and Scl expression and to determine the precise developmental stage where BMP-4 functions to establish the hematopoietic system.
Specific aim I : Further characterize molecular events involved in the generation of Flk-1 + and SCL + cells. Our studies indicate that the activation of both map kinase and Smadl pathways by BMP-4 is critical for the generation of Flk-1 + cells. Furthermore, recent studies suggest that the transcription factor GATA-2 is one component that binds Scl enhancer region. Thus, our aim is to further understand mechanisms controlling Flk-1 and Scl gene expression.
Specific aim II. Examine the role of BMP-4 mediated signals in hemangioblast development. Our experiments indicate that BMP-4 is critical for the generation of Flk-1 + cells. What is not clear from our current studies is whether BMP-4 mediated signals are still required after the Flk-I + cell stage in establishing hematopoiesis.
Our specific aim i s to utilize Flk-l-cre mice and conditional Alk-3 (BMP-4 receptor) knockout mice to determine whether BMP-4 mediated signals are obligatory for the generation of the hemangioblast within the Flk-1 + cells.
Specific aim III. Examine the role of BMP-4 mediated signals in hematopoietic and endothelial cell development. Subsequent to hemangioblast development, hematopoietic and endothelial cell lineage commitment commences.
Our specific aim i s to determine whether BMP-4 mediated signals are required for hematopoietic lineage commitment from the hemangioblast. Scl-cre mice and conditional Alk-3 knockout mice will be utilized.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL063736-06
Application #
6845676
Study Section
Hematopoiesis Study Section (HP)
Program Officer
Thomas, John
Project Start
2004-01-01
Project End
2007-12-31
Budget Start
2005-01-01
Budget End
2005-12-31
Support Year
6
Fiscal Year
2005
Total Cost
$306,000
Indirect Cost
Name
Washington University
Department
Pathology
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Choi, Kyunghee (2018) ETS transcription factor ETV2/ER71/Etsrp in haematopoietic regeneration. Curr Opin Hematol 25:253-258
Kabir, Ashraf Ul; Lee, Tae-Jin; Pan, Hua et al. (2018) Requisite endothelial reactivation and effective siRNA nanoparticle targeting of Etv2/Er71 in tumor angiogenesis. JCI Insight 3:
Davis, Jennifer A; Koenig, Andrew L; Lubert, Allison et al. (2018) ETS transcription factor Etsrp / Etv2 is required for lymphangiogenesis and directly regulates vegfr3 / flt4 expression. Dev Biol 440:40-52
Zhao, Haiyong; Xu, Canxin; Lee, Tae-Jin et al. (2017) ETS transcription factor ETV2/ER71/Etsrp in hematopoietic and vascular development, injury, and regeneration. Dev Dyn 246:318-327
Zhao, Haiyong; Choi, Kyunghee (2017) A CRISPR screen identifies genes controlling Etv2 threshold expression in murine hemangiogenic fate commitment. Nat Commun 8:541
Xu, Can-Xin; Lee, Tae-Jin; Sakurai, Nagisa et al. (2017) ETV2/ER71 regulates hematopoietic regeneration by promoting hematopoietic stem cell proliferation. J Exp Med 214:1643-1653
Sumanas, S; Choi, K (2016) ETS Transcription Factor ETV2/ER71/Etsrp in Hematopoietic and Vascular Development. Curr Top Dev Biol 118:77-111
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
Kim, Ki-Wook; Zhang, Nan; Choi, Kyunghee et al. (2016) Homegrown Macrophages. Immunity 45:468-470
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

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