Dental applications for a novel osteoclast inhibitor

描述(由申请人提供)：依诺沙星和Bhib16最近在体外试验中被确认为破骨细胞形成和功能的新抑制剂。以前的研究表明，空泡H-ATPase B亚单位(V-ATPase)与肌动蛋白细丝相互作用的抑制剂应该能阻断破骨细胞吸收骨的能力。一种基于计算机的小分子筛选，预测可以结合B亚基的肌动蛋白结合表面，并抑制其与肌动蛋白细丝的相互作用，确定为依诺沙星和Bhib16。然后，这些分子被证明在试管中阻止纯兔子肌肉肌动蛋白细丝与B亚基的结合。在骨化三醇刺激的小鼠骨髓培养中，检测依诺沙星和Bhib16对破骨细胞形成和功能的影响。在大约10毫升的浓度下，这两种分子都阻断了破骨细胞的形成和预分化破骨细胞的功能。相反，这些分子对骨髓培养中产生的成骨细胞的数量没有明显的影响，根据碱性磷酸酶阳性细胞的数量判断，对MC3T3-E1成骨细胞也没有明显的影响。这些数据表明依诺沙星和Bhib16可能通过新的机制抑制破骨细胞，而对成骨细胞没有抑制作用。这项建议的总体目标是进行初步测试，以确定依诺沙星和Bhib16是否有希望作为药物用于各种牙科应用，在这些应用中，抑制破骨细胞性骨吸收将是有益的。提出以下中心假设：依诺沙星和Bhib16是通过靶向与肌动蛋白细胞骨架结合的V-ATPase来抑制破骨细胞性骨吸收的一类新型治疗剂的第一个例子。提出了四个具体目标。在目标1中，我们将开发一种利用Elvax的依诺沙星和Bhib16的局部缓释方法。许多研究已经将Elvax用于类似的应用。在目标2中，依诺沙星和Bhib16将在已建立的牙周炎大鼠模型中测试其减少牙周骨丢失的能力。目的3将利用已建立的雪貂系统测试依诺沙星和Bhib16治疗是否能减少与再次植入相关的吸收。目的4将在一个大鼠模型上测试依诺沙星和Bhib16阻止正畸牙移动的能力。这可能为提供正畸支抗提供一种新的方法。这项研究应该为V-ATPase-肌动蛋白相互作用的抑制剂在牙科手术中的应用提供初步证据。支持目前的研究是必要的，以便提供足够的初步数据来确定大规模临床前研究是否合理。鉴于拟议的研究代表了一种将生物活性小分子用于牙科应用的新鲜和创新的方法，并可能产生巨大的临床影响，我们认为NIH以R21拨款的形式提供支持是必要的。 公共卫生相关性：一种抑制破骨细胞性骨吸收的生物活性物质将在各种牙科应用中有用。一种新型的破骨细胞功能小分子抑制剂依诺沙星和Bhib16已经通过基于超级计算机的检测而被鉴定出来。目前的提案将在动物模型中对这些分子进行试点临床前测试，以检查它们是否适合牙周、牙髓和正畸用途。

DESCRIPTION (provided by applicant): Enoxacin and Binhib16 were recently identified as novel inhibitors of osteoclast formation and function in in vitro assays. Previous studies had indicated that inhibitors of an interaction between the B-subunit of vacuolar H+ATPase (V-ATPase) and actin filaments should block the ability of osteoclasts to resorb bone. A computer based screen for small molecules predicted to bind the actin binding surface of subunit B and inhibit its interaction with actin filaments identified enoxacin and Binhib16. These molecules were then shown to block binding of pure rabbit muscle actin filaments to B-subunit in the test tube. Enoxacin and Binhib16 were tested for effects on osteoclast formation and function in vitro in calcitriol-stimulated mouse marrow cultures. Both blocked osteoclast formation and the function of pre-differentiated osteoclasts at a concentration of approximately 10 <M. In contrast, these molecules did not have detectable effects on the number of osteoblasts produced in marrow cultures, as judged by the number of alkaline phosphatase positive cells, or on MC3T3-E1 osteoblasts. These data suggest that enoxacin and Binhib16 might inhibit osteoclasts by novel mechanisms, without having inhibitory effects on osteoblasts. The overall goal of this proposal is to perform preliminary tests to determine whether enoxacin and Binhib16 hold promise as agents for use in the treatment of various dental applications in which inhibition of osteoclastic bone resorption would be beneficial. The following central hypothesis is proposed: Enoxacin and Binhib16 are the first examples of a new class of therapeutic agents for the inhibition of osteoclastic bone resorption by targeting V-ATPase binding to the actin cytoskeleton. Four specific aims are suggested. In Aim 1, we will develop a method for sustained local release of enoxacin and Binhib16 making use of Elvax. Numerous studies have utilized Elvax for similar applications. In Aim 2, enoxacin and Binhib16 will be tested for its capacity to reduce periodontal bone loss in a well-established rat model of periodontitis. Aim 3 will test whether treatment with enoxacin and Binhib16 reduces resorption associated with re- implantation making use of an established ferret system. Aim 4 will test the capacity of enoxacin and Binhib16 to block orthodontic tooth movement in a rat model. This could provide a novel means for providing orthodontic anchorage. This study should provide initial evidence regarding the potential of inhibitors of V-ATPase-actin interactions for use in dental procedures. Support for the current studies is necessary in order to provide sufficient preliminary data to determine whether large scale pre-clinical studies are justified. Given that the proposed research represents a fresh and innovative approach to the use of bioactive small molecules for dental applications, and could have a large clinical impact, we believe that NIH support in the form of an R21 grant is warranted. PUBLIC HEALTH RELEVANCE: A bioactive agent that inhibits osteoclastic bone resorption would be useful for various dental applications. Novel small molecule inhibitors of osteoclast function, enoxacin and Binhib16, have been identified using a supercomputer-based assay. The current proposal will conduct pilot preclinical tests of these molecules in animal models to examine their suitability for periodontic, endodontic and orthodontic uses.