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Functional analysis of nitric oxide metabolites in hard tissues

硬组织中一氧化氮代谢物的功能分析

基本信息

批准号：
18592049
负责人：
MIYAMOTO Yoichi
金额：
$ 2.57万
依托单位：
Showa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

Nitric oxide (NO) acts as an infra- and intercellular signaling molecule. In addition to the cGMP-dependent signaling, it has been suggested that signals are transmitted by chemical modifications of biological molecules by NO and NO metabolites. In this study, we investigated the roles of NO and its metabolites in the differentiation and function of the cells which constitute hard tissues. First, we established their cell culture models. Namely, odontoblast differentiation, inflammation-induced osteoclast differentiation, and chondrocyte culture as a model of inflammatory joint diseases. We obtained the following findings using these models Expression of inducible type of NO synthase (iNOS) was induced in the pulp after abrasion of teeth without exposure of pulp. Then we studied the effects of NO on the pulp cell growth and differentiation. NO suppressed the proliferation of pulp cells and promoted the odontoblastic differentiation and mineralization, suggesting NO is involved in the f … More ormation of reparative dentin after tooth abrasion. TNF-α-induced bone resorption in ex-vivo was strongly suppressed in the iNOS-knockout calvaria In addition, osteoclast differentiation in the presence of TNF-α was retarded in the iNOS-knockout cultures NO-dependent formation of nitrated nucleotides was observed in the course of osteockast differentiation in the wild type cells. Finally, we studied the metabolism of extracellular matrix of chondmcytes after IL-1 exposure and found that IL-1 induced and activated the phagocyte-type NADPH-oxidase in the chondrocytes through the activation of TRAF-6 and NF-κB. We had already reported that IL-1 induced the expression of iNOS and formation of peroxynitrite, a reaction product of NO and superoxide in chondrocytes. The present results indicate that one of the sources of superoxide is the phagocyte type NADPH-oxidase. Interestingly, extra- and intracellular pH was decreased in the NADPH-oxidase-dependent manner, which in turn activated hyaluronidase and accelerated the loss of extracellular matrix. Less

一氧化氮 (NO) 充当细胞内和细胞间信号分子。除了 cGMP 依赖性信号传导之外，有人认为信号是通过 NO 和 NO 代谢物对生物分子进行化学修饰来传递的。在这项研究中，我们研究了NO及其代谢物在构成硬组织的细胞的分化和功能中的作用。首先，我们建立了他们的细胞培养模型。即成牙本质细胞分化、炎症诱导的破骨细胞分化以及作为炎症性关节疾病模型的软骨细胞培养。我们使用这些模型获得了以下发现：在牙齿磨损后不暴露牙髓的情况下，诱导型一氧化氮合成酶（iNOS）的表达在牙髓中被诱导。然后我们研究了NO对牙髓细胞生长和分化的影响。 NO抑制牙髓细胞的增殖，促进成牙本质细胞的分化和矿化，表明NO参与牙齿磨损后修复性牙本质的形成。在 iNOS 敲除颅盖中，TNF-α 诱导的离体骨吸收受到强烈抑制。此外，在 iNOS 敲除培养物中，TNF-α 存在下的破骨细胞分化被延迟。在野生型细胞的破骨细胞分化过程中，观察到 NO 依赖性硝化核苷酸的形成。最后，我们研究了IL-1暴露后软骨细胞细胞外基质的代谢，发现IL-1通过激活TRAF-6和NF-κB诱导并激活软骨细胞中的吞噬细胞型NADPH氧化酶。我们已经报道过IL-1诱导iNOS的表达和过氧亚硝酸盐的形成，过氧亚硝酸盐是软骨细胞中NO和超氧化物的反应产物。目前的结果表明超氧化物的来源之一是吞噬细胞型NADPH-氧化酶。有趣的是，细胞外和细胞内的pH值以NADPH氧化酶依赖性方式降低，进而激活透明质酸酶并加速细胞外基质的损失。较少的