SUPEROXIDE AND BONE RESORPTION

描述：(改编自《调查者摘要》)超氧化物 世代有助于破骨细胞性骨吸收。白细胞 通过激活膜结合的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 细胞膜的一侧。初步数据显示， 破骨细胞超氧化物产生可被NADPH氧化酶抑制 抑制剂。因此，中心假说提出NADPH氧化酶 在破骨细胞-骨界面上产生超氧化物 超氧化物直接促进骨基质蛋白的降解。 将遵循三条线进行调查。首先，申请者 计划确定碘离子对NADPH氧化酶的抑制作用 化合物，二苯基离子大大减少了产量 非刺激性和刺激性破骨细胞中的超氧化物歧化 再吸收。这些实验将使用正常的颅骨外植体 和骨质疏松症小鼠。小眼症小鼠模型提供了 强有力的证据表明，增加超氧化物的产生可以刺激 破骨细胞性骨吸收。一种特殊的NADPH--二苯基离子 氧化酶抑制剂，将被用来确定是否存在关联 骨吸收和破骨细胞超氧化物之间的关系 一代。NADPH氧化酶的亚细胞定位 小鼠破骨细胞将使用特异性抗体进行检测 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氧化酶的含量与超氧化物产生的区域相关， 用电子显微镜观察地福马赞颗粒的形态。 最后，至少存在三种增加NADPH氧化酶的机制。 白血球。这些措施包括：(A)总额增加；(B) 亚细胞分布的变化；以及(C)状态的变化 现有酶的激活。 NADPH氧化酶亚细胞定位的初步研究 超氧化物生产的相应领域应该有助于洞察 探讨该酶在调节破骨细胞性骨吸收中的作用 活动。负责超氧化物歧化的特异酶(S)的研究 形成和识别导致变化的机制 这些酶的功能将为缺陷提供新的见解(S) 在患有骨质疏松症和骨质疏松症的动物和人类身上。成功 这些研究的完成应为改进治疗铺平道路 应用NADPH氧化酶刺激物治疗骨化症的策略 和骨质疏松症，使用抑制剂。

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.