2000 Fiscal Year Final Research Report Summary
| Project/Area Number |
11670818
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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 |
Dermatology
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| Research Institution | CHIBA UNIVERSITY |
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Principal Investigator |
SHINKAI Hiroshi Chiba University, School of Medicine, Professor, 医学部, 教授 (90030957)
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| Co-Investigator(Kenkyū-buntansha) |
ENDO Hideharu Chiba University, School of Medicine, Assistant, 医学部, 助手 (50282489)
UTANI Atsushi Chiba University, University Hospital, Lecturer, 医学部・付属病院, 講師 (10292707)
HATAMOCHI Atsushi Chiba University, School of Medicine, Associate Profess, 医学部, 助教授 (90172923)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Ehlers-Danlos / p38MAPK / Decorin / Cytokines / Dermatopontin |
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| Research Abstract |
We examined the role of p38 MAPK incutaneous fibrosis by using cytokines related to regulation of extracellular matrix.
We detected p38 MAPK phosphorylation/activation in cultured dermal fibroblasts when stimulated with PDGF-BB, TGF-β, or IL-4. Induction of matrix metalloproteinase (MMP)-1 mRNA by PDGF-BB was enhanced with a specific inhibitor of p38 MAPK, suggesting that p38 MAPK would function as a negative regulator for MMP-1 mRNA level. This observation may correlate with the findings that fibroblasts obtained from hypertrophic scar exhibited increased phosphorylation of p38 MAPK as well as decreased MMP-1 mRNA level compared to nonlesional fibroblasts.
Western blotting revealed that the deficiency of dermatan sulfate was due to the defect of decorin core protein. β-xyloside, an initiator of dermatan sulfate glycosaminoglycan chain elongation, enhanced the synthesis of dermatan sulfate in the fibroblasts of Ehlers-Danlos syndrome to a similar extent to that of control. This result in
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dicated that the enzymes for the elogation of dermatan sulfate side chains were normal. Northern blotting demonstrated remarkable reduction of decorin mRNA level. cDNA and exons sequencing analysis showed there was no mutation in decorin gene of the patient. IL-1β stimulated decorin expression to about 140% in control fibroblasts while about 110% in patient fibroblasts. On the other hand, TGF-β1 resulted in 40% reductions of decorin expression in both control and patient fibroblasts. These data suggested that reduced decorin expression of fibroblasts from the patient may be due to abnormalities in the regulatory regions.
We generated the DPT-null mice by gene targeting to study the biological function of DPT.DPT-null mice were born alive, grew to normal size and were fertile. DPT-null mice showed Ehlers-Danlos syndrome-like skin laxity and fragility, although these mice did not exhibit obvious histological abnormalities of the skin. In electronmicroscopic studies, the diameter of collagen fibrils in skin from DPT-null mice is remarkably greater than that of littermate control and individual fibrils in DPT-null mice exhibit irregular contours. In addition, the absence of DPT leads to skin fragility confirmed by tensile strength text. The values of tensile strength measurements of the skin are significantly reduced in DPT-null mice as compared with normal littermate. These results indicate that DPT plays an important role in collagen fibrillogenesis in vivo. Less
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