| Project/Area Number |
06672056
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
矯正・小児・社会系歯学
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| Research Institution | THE UNIVERSITY OF TOKUSHIMA |
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Principal Investigator |
SUMITANI Koji TOKUSHIMA UNIVERSITY,SCHOOL OF DENTISTRY,ASSISTANT PROFESSOR, 歯学部・附属病院, 講師 (30206586)
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| Co-Investigator(Kenkyū-buntansha) |
TAGAMI Kahori (KONDOH Kah) TOKUSHIMA UNIVERSITY,SCHOOL OF DENTISTRY,RESEARCH ASSOCIATE, 歯学部, 助手 (50274238)
HIURA Kenji TOKUSHIMA UNIVERSITY,SCHOOL OF DENTISTRY,ASSISTANT PROFESSOR, 歯学部・附属病院, 講師 (20228696)
石川 啓詞 徳島大学, 歯学部, 助手 (70253218)
上岡 寛 徳島大学, 歯学部, 助手 (80253219)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1995: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1994: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Cathepsin L / Osteoclast(s) / Bone resorption / Calcitonin / Proton / カテプシン / 歯牙移動 |
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| Research Abstract |
Osteoclasts are multinucleated giant cells responsible for the resorption of the calcified extracellular bone matrix. The degradation of the bone matrix protein including type I collagen is a key process for osteoclastic bone resorption. It has been suggested that lysosomal cysteine proteinase in osteoclasts is essential to degrade bone collagen, but the proteinase(s) for this collagenolysis have not been identified.
In this study, the participation of cathepsin L on osteoclastic bone resorption was investigated and the results obtained were as follows.
1) In cultured rat bone marrow cells, parathyroid hormone (PTH)-stimulated bone resorption was markedly suppressed by all of specific and non-specific inhibitors of cathepsin L tested but not by a specific inhibitor (CA-074) of cathepsin B.
2) In rats with bone resorption stimulated by a low calcium diet, serum calcium level was decreased by an intraperitoneal injection of cathepsin Linhibitors but not by CA-074.
3) Activities of cathepsin L and B were shown to be more than 80% of total proteinase activity in the culture medium of rat bone marrow cells.
4) In bone marrow cells cultured on bone slices, PTH increased both bone resorption and cathepsin L activity in the medium and these increases were suppressed by calcitonin.
5) The cultured bone marrow cells secreted cathepsin L as 39kD molecule and the secretion was suppressed by calcitonin.
6) The 39kD cathepsin L purified from rat long bones was converted to 25kD cathepsin L under acidic condition.
7) Rat long bone-derived 25kD cathepsin L as well as purified cathepsin L of rat liver degraded type I collagen at pH 4.05.0.
These results suggested that cathepsin L secreted from osteoclast plays a crucial role in the degradation of bone matrix proteins including type I collagen during bone resorption.
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