SUPEROXIDE AND BONE RESORPTION

描述：（改编自研究者摘要）超氧化物 生成有助于骨吸收。白色细胞 通过激活NADPH氧化酶产生超氧化物， 酶，导致在非细胞质上产生超氧化物 细胞膜的一面。初步数据显示， NADPH氧化酶可抑制骨钙素超氧化物的产生 抑制剂.因此，中心假说提出NADPH氧化酶 在破骨细胞-骨界面产生超氧化物， 超氧化物直接促进骨基质蛋白的降解。 将遵循三条调查路线。首先，申请人 计划确定碘鎓盐是否抑制NADPH氧化酶 化合物，二亚苯基iondonium显着减少生产 骨刺激前后破骨细胞超氧化物歧化酶的变化 再吸收这些实验将使用正常人的颅骨外植体， 和骨硬化小鼠。小眼小鼠模型提供了 强有力的证据表明，增加超氧化物的产生可以刺激 骨吸收二亚苯基离子，一种特异性NADPH 氧化酶抑制剂，将用于确定是否存在相关性 骨吸收率和骨钙素过氧化物 一代第二，NADPH氧化酶的亚细胞定位， 小鼠破骨细胞将使用特异于 细胞色素b558的亚基，NADPH氧化酶的主要成分 酵素这些研究将确定免疫细胞化学定位 NADPH氧化酶的活性与超氧化物的产生区域相关， 通过二甲瓒颗粒的电子显微镜可视化测量。 最后，至少有三种增加NADPH氧化酶的机制存在， 白色细胞。其中包括：（a）增加总额;（B） 亚细胞分布的变化;和（c）状态的变化 激活现有的酶。 NADPH氧化酶的亚细胞定位及其在细胞内的表达 超氧化物产生的相应领域应有助于了解 研究这种酶在调节骨吸收中的作用， 活动负责超氧化物的特定酶的描述 形成和确定机制导致的变化， 这些酶的功能将提供对缺陷的新见解 在动物和人的骨硬化症和骨质疏松症。成功 这些研究的完成应该为改善治疗铺平道路 用NADPH氧化酶刺激剂治疗骨硬化症的策略 和骨质疏松症的治疗。

DESCRIPTION: (Adapted from the Investigator's Abstract) Superoxide generation contributes to osteoclastic bone resorption. White cells generate superoxide by activating NADPH oxidase, a membrane-bound enzyme, which results in generation of superoxide on the non-cytoplasmic side of the cellular membranes. Preliminary data suggest that osteoclastic superoxide production can be inhibited by an NADPH oxidase inhibitor. Thus, the central hypothesis proposes that NADPH oxidase generates superoxide at the osteoclastic-bone interface and this superoxide contributes directly to degradation of bone matrix proteins. Three lines of investigation will be followed. First, the applicants plan to determine if inhibition of NADPH oxidase by an iodonium compound, diphenylene iondonium significantly reduces the production of superoxide in osteoclasts during unstimulated and stimulated bone resorption. These experiments will use calvarial explants from normal and osteopetrotic mice. The microphthalmic mouse model has provided strong evidence that increased superoxide production can stimulate osteoclastic bone resorption. Diphenylene iondonium, a specific NADPH oxidase inhibitor, will be used to determine if there is a correlation between the rates of bone resorption and osteoclastic superoxide generation. Second, the subcellular localization of NADPH oxidase in mouse osteoclasts will be determined using antibodies specific for subunits of cytochrome b558, a major component of the NADPH oxidase enzyme. These studies will determine if the immunocytochemical location of NADPH oxidase correlates with areas of superoxide production, measured by electron microscopic visualization of diformazan granules. Finally, at least three mechanisms of increasing NADPH oxidase exist in white cells. These include: (a) an increase in the total amount; (b) a change in the subcellular distribution; and (c) a change in the state of activation of existing enzyme. Mapping out the subcellular localization of NADPH oxidase and the corresponding areas of superoxide production should contribute insight into the role of this enzyme in modulating osteoclastic bone resorptive activity. Delineation of a specific enzyme(s) responsible for superoxide formation and identifying the mechanisms leading to alterations in the function of these enzymes will provide new insight into the defect(s) in animals and humans with osteopetrosis and osteoporosis. Successful completion of these studies should pave the way to improved treatment strategies for treating osteopetrosis with stimulators of NADPH oxidase and osteoporosis, with inhibitors.