1999 Fiscal Year Final Research Report Summary
Egr-1 and TGF-beta gene expression of dermal fibroblasts in de-differentiation and re-differentiation system
| Project/Area Number |
10671689
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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 |
Plastic surgery
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| Research Institution | Kanazawa Medical University |
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Principal Investigator |
ISHIKURA Naotaka Kanazawa Medical University, Associate professor, 医学部, 助教授 (60159712)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEUCHI Ikuto Kanazawa Medical University, Assistant professor, 医学部, 講師 (70262623)
YOSHIDA Jun Kanazawa Medical University, Assistant professor, 医学部, 助手 (40257473)
NISHIKAWA Katuzo Kanazawa Medical University, Professor, 医学部, 教授 (10029960)
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| Project Period (FY) |
1998 – 1999
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| Keywords | fibroblast / TGF-β / EGR-1 / Smad / Tak-1 / wound healing |
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| Research Abstract |
We hypothesized that differentiated fibroblasts are mature fibroblasts in normal skin dermis and that the dedifferentiated fibroblasts are those in granulation and scar tissue. Before establishing in vitro system, we investigated in vivo expression of TGF-beta and Egr-1 in fibroblasts using incisional wound model of rat skin. Immediately after wounding, fibroblasts migrating toward wound margin showed less immunoreactivity of TGF-betas. This hyporeactivity returned to normal degree several days after wounding. This finding suggests that the TGF-beta action diminishes while fibroblasts migrate and returns to normal when fibroplasia phase starts. Egr-1 positive cells were seen in dermis adjacent to wound immediately after wounding. There cells may be blood-borne macrophage because these cell were positively stained with ED-1, which is specific not to tissue macrophage but to blood-borne macrophage. Appearance of Egr-1 positive cells were transient and few positive cells were seen three days after wounding. We also immunohistochemically investigated expression of TGF-betas and Egr-1 in human skin, granulation tissue, and hypertrophic scar. This again failed the apparent expression of those factors in fibroblasts. Instead, we found dynamic expression of TGF-betas in epidermal cells in wounded skin of human as well as that of rat. Therefore, we further investigated TGF-beta isoforms was seen during epithelialization. We also found Tak-1 and Smads, signal transudation molecules of TGF-betas, were expressed during wound healing process. This may be the first study that showed the presence of TGF-beta signal transudation pathway in epidermal cells in vivo.
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