1994 Fiscal Year Final Research Report Summary
Analysis of regulatory mechanisims of thrombocytopoiesis.
| Project/Area Number |
05454335
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Hematology
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| Research Institution | Tokyo Women's Medical College |
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Principal Investigator |
MIZOGUCHI Hideaki Deptartment of Hematology, Tokyo Women's Medical College Professor, 医学部, 教授 (70049021)
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| Co-Investigator(Kenkyū-buntansha) |
MORI Naoki Deptartment of Hematology M.D., 医学部, 助手 (20241078)
TERAMURA Masanao Deptartment of Hematology M.D., 医学部, 講師 (40188686)
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| Project Period (FY) |
1993 – 1994
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| Keywords | megakaryocytopoiesis / signal transduction / Vav / MAP kinase / Jak2 / Evi-1 / myb |
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| Research Abstract |
The mechanisim of proliferation and differentiation of human megakaryocytic cells has been investigated.
1. Tyrosine phosphorylation of c-Kit receptor, Vav, MAP kinase was observed in a megakaryoblastic leukemia cell line, CNK,by the stimulation of SCF.When GM-CSF (granulocyte-macrophage colony-stimulating factor) was added to CMK cells, tyrosine phosporylation of Jak2 and MAP kinase was revealed.
2. The role of Evi-1 on megakaryocytic cells was investigated. Evi-1 m-RNA was expressed in CMK and Meg-J cells. However, expression of Evi-1 m-RNA did not increase after stimulation of TPA (12-0-tetradecanoyl phorbol-13-acetate), IL-3 (interleukin-3), IL-6 or IL-11. Myb m-RNA was expressed in CMK cells, however, additon of antisense oligonucleotide of myb to CMK cells chould not suppress the proliferation, suggesting that myb has no role for the proliferation of CMK cells.
3. When Meg-J cells were cultured in the presence of K252a, a protein kinase C inhibitor, the ploidy was dramatically increased. This assay system may be use ful for studying the mechanism of polyploidization of megakaryocytic cells.
4. Enhancement of CD41 expression of CMK cells by TPA was ablogated by Herbimycin A,a tyrosine kinase inhibitor, indicating that TPA-induced CD41 expression was mediated by tyrosine kinases.
5. It has been shown that IL-11 is an autocrine growth factor for human megakaryoblastic leukemia cells. Therefore, we next ivestigated whether IL-11 act as an autocrine growth factor for normal human mekakaryocytic cells. Human megakaryocytes obtained by normal bone marrow cells did not express IL-11 mRNA,indicating that IL-11 is not a autocrine growth factor in normal megakaryocyotopoiesis.
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