2007 Fiscal Year Final Research Report Summary
Elastic System Fibers Formation and Degradation in the Periodontal Tissues
| Project/Area Number |
17591920
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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 |
Morphological basic dentistry
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| Research Institution | Health Sciences University of Hokkaido |
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Principal Investigator |
YAJIMA Toshihiko Health Sciences University of Hokkaido, School of Dentistry, Professor (10018749)
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| Co-Investigator(Kenkyū-buntansha) |
IRIE Kazuharu Health Sciences University of Hokkaido, School of Dentistry, Assistant Professor (70223352)
TSURUGA Eichi Fukuoka Dental University, School of Dintistry, Associate Professor (30295901)
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| Project Period (FY) |
2005 – 2007
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| Keywords | elastic system fibers / microfibrils / elastin / fibrillin / MAGP-1 / MMP-2 / periodontal tissues / fibroblasts |
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| Research Abstract |
Elastic system fibers, comprised of microfibrils and tropoelastin, are extracellular components of periodontal tissue. Elastogenesis requires a microfibril template onto which tropoelastin is deposited. The microfibrils, which are made up mainly of fibrillins, microfibril-associated glycoporoteins (MAGPs) and fibulins, are thought to serve as a template structure that guides tropoelastin desposition.
In this study, we used the RNA interference (RNAi) technique to estanblish MAGP-1 and fibrillin-2 gene-specific knock-downs individually in human gingival fibroblasts (HGF). We then examined the extracellular deposition of tropoelastin by western blotting. These two genes were specifically suppressed to <30% of the control level, and this was responsible for the diminution of tropoelastin deposition. An immunof;uorescence study also cinfrimed that RNAi-mediated down-regulation of MAGP-1 or fibrillin-2 led to the loss of tropoelastin immunoreactivity. These results suggest that MAGP-1 and fibrillin-2 are associated with the extracellular deposition of tropoelastin during elastic fiber formation in HGF in vitro.
The process of elastic system fibersr remodeling is not fully understood. We examined whether matrix metaroproteinases (MMPs) are involved in remodeling of fibrillins by HGF and human periodontal ligament fibroblasts (HPLF). Active MMP-2 appeared as cell-membrane-associated or in extracellular matrix only in HPDF cell layers. The addition of MMP inhibitor or tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) significantly increased fibrillin-2 accumulation in HPDF cell layers, suggesting that active MMP-2 may degrade fibrillin-2, and that MMPs may play a role in the remodeling of elastic system fibers in periodontal ligament.
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