2004 Fiscal Year Final Research Report Summary
Molecular mechanism of vascular endothelial/mural cell differentiation by receptor tyrosine kinases
| Project/Area Number |
15570110
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional biochemistry
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MIYAZAWA Keiji The University of Tokyo, Graduate School of Medicine, Associate Professor, 大学院・医学系研究科, 助教授 (40209896)
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| Co-Investigator(Kenkyū-buntansha) |
WATABE Tetsuro The University of Tokyo, Graduate School of Medicine, Research Associate, 大学院・医学系研究科, 助手 (00334235)
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| Project Period (FY) |
2003 – 2004
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| Keywords | endothelial cells / mural cells / tyrosine kinase / growth factors / differentiation |
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| Research Abstract |
In the present study, we examined the roles of receptor tyrosine kinases in differentiation of mouse embryonic stem (ES) cell-derived VEGFR2^+ cells into endothelial cells and mural cells.
(1)VEGFR3 signaling in endothelial differentiation
VEGFR3 is a receptor for VEGF-C and VEGF-D. In order to examine the role of VEGFR3 in endothelial differentiation, we established ES cells expressing VEGFR3 by Supertransfection technique and then prepared VEGFR2^+ cells through in vitro differentiation and MACS. These cells differentiated into endothelial cells and expressed lymphatic endothelial marker LYVE-1 in the presence of VEGF-C. VEGF-C stimulates VEGFR3 as well as VEGFR3, whereas VEGF-C (C152S) mutant exclusively stimulates VEGFR3. VEGF-C (C152S) failed to induce endothelial differentiation. Upon stimulation with VEGF-C, VEGFR2 signaling is indispensable for endothelial differentiation, and VEGFR3 signaling additionally confers lymphatic endothelial-like phenotypes to endothelial cells.
(2)FGF signaling in endothelial/smooth muscle differentiation
We examined the differentiation of VEGFR2^+ cells in the presence of FGF-2 for 2 days. 45% of the cells differentiated PECAM1^+ endothelial cells, 20% of them differentiated into SMA^+ mural cells, and 35% of them remained negative for both markers. FGF-2 thus does not direct cell differentiation to one specific lineage. We also examined the co-stimulatory effect of VEGF-A and FGF-2. Whereas VEGF-A caused exclusive endothelial differentiation, VEGF-A/FGF-2 co-stimulation induced 95% endothelial cells and 5% mural cells. Notably mural cells attached to the entdothelial sheets. We found that the cell-cell communication was mediated through endogenonus PDGF-B/PDGFRβ signaling.
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