| Project/Area Number |
16390227
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | Kumamoto University |
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Principal Investigator |
OGAWA Minetaro Kumamoto University, Institute of Molecular Embryology and Genetics, Professor, 発生医学研究センター, 教授 (70194454)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥13,700,000 (Direct Cost: ¥13,700,000)
Fiscal Year 2005: ¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 2004: ¥7,100,000 (Direct Cost: ¥7,100,000)
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| Keywords | Vascular endothelial cells / Cardiomyocytes / Vascular smooth muscle cells / Mesoderm / Embryonic stem cells / Cell movement / Cell adhesion / Transcription factors / 試験管内分化 / タイムラプス解析 |
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| Research Abstract |
The mechanism by which primary plexus and subsequent vascular tree which consists of large and small vessels form in the process of vertebrate embryogenesis is largely unknown. In vitro differentiation system of murine ES cells serves as a means to break down the complicated processes of vascular development into cellular events which can be monitored in real time. We have developed a culture system in which endothelial cells, cardiomyocytes and smooth muscle cells differentiate from a single mesodermal precursor cell derived from ES cells. This culture system identified tri-potent cardio-vascular progenitor cells in the mesodermal cell population.
ES cell-derived endothelial cell colonies generated on stromal cell layer have been used as an in vitro model to examine the behavior of individual endothelial cells in response to various angiogenic stimuli such as VEGF. The VEGF signal was shown to induce elongation and dispersion of endothelial cells. We identified a forkhead-type transcri
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ption factor Foxo1 as a regulatory molecule in the elongation reaction of endothelial cells, which might account for the severe abnormality of angiogenesis found in foxo1-deficient mouse embryos.
We produced ES cell clones which express VE-cadherin-VENUS or claudin 5-VENUS under the regulation of VE-cadherin gene promoter/enhancer. Time-lapse analysis of ES cell-derived endothelial cell colonies revealed an active movement of endothelial cells. Integrity of the VE-cadherin-based adherens junction and the claudin 5-based tight junctin was maintained despite the high motility of endothelial cells. A dynamic remodeling process of cell junctions was identified at the leading edges of moving endothelial cells. Modulation of endothelial cell motility might be an important process which drives the vascular development at the cell level.
Fate tracing analyses by using VE-cadherin promoter-Cre transgenic mice showed that cardiac ischemia activate VE-cadherin promoter in both pre-existing vascular cells and bone marrow cells involved in neovascularization. We also demonstrated that over-expression of a transcription factor c-Myb increases the frequency of hemogenic precursors in the endothelial cell population, which provides a clue to how hemogenic endothelial cells commit to definitive hematopoietic cell lineages during the mouse embryogenesis. Less
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