Role of OC-STAMP expressed on human osteoclasts in periodontitis

本申请为“行政补充，以表彰卓越的DEIA导师（NOT-OD-23- 002）”的活动R 01赠款项目（DE 029709），题为“OC-STAMP在人类表达的作用 牙周炎中的破骨细胞”，建议建立人源化的牙周炎小鼠模型， 破骨细胞表达的OC-STAMP在牙周炎中的致病作用的 NSG-SGM 3-W 41小鼠品系是开发的最先进的免疫缺陷小鼠品系之一 由杰克逊实验室的舒尔茨博士所做的实验使我们能够重建包含这两种物质的完整免疫区室。 人造血干细胞（hHSC）移植后的髓样和淋巴样细胞群 而不通过辐射调节。最近使用人源化NSG小鼠的研究表明， 来源于hHSC的单核细胞谱系细胞可以在NSG小鼠的替代体中检测到。相关 通过对R 01项目的研究，我们初步发现，牙龈卟啉单胞菌（P. gingivalis，Pg）是牙龈卟啉单胞菌的关键致病菌， 牙周炎，通过人OC前体细胞增加OC-STAMP的表达。由于小鼠淋巴细胞 口服接种Pg不会引起致病性免疫应答，但有人认为， 在人源化小鼠中处于小鼠MHC-II的控制之下可能不会产生足够量的RANKL， 在人源化免疫缺陷小鼠中引起牙周炎。然而，我们发现牙周骨丢失和 RAG 1免疫缺陷小鼠的结扎连接可诱导RANKL的局部产生，表明 淋巴细胞不是结扎诱导的小鼠牙周炎中RANKL的主要细胞来源。 此外，由于OC-STAMP由OC和OC前体特异性表达，而不是由其他细胞表达，因此， 在来自hHSC的淋巴细胞中，预期给予人源化小鼠的抗OC-STAMP Ab 只作用于人的OC我们假设，PG依赖性上调OC-STAMP的表达， 人OC可促进人源化小鼠中的致病性骨吸收， 牙周炎本研究将从以下两个方面对这一假说进行验证：1）检测抗OCST抗体的作用 对在接种或不接种Pg的人源化小鼠中诱导的牙周炎的发作和进展的影响，以及2） 确定人OC中促进RANKL诱导OC生成的人OC-STAMP配体。 在成功完成这项拟议的研究后，预计人OC-STAMP的作用 将确定牙周炎中人OC表达的水平。这个人源化的牙周炎小鼠模型 将提供一个平台，了解分子表达的人OCS的生理背景。

This application for “Administrative Supplements to Recognize Excellence in DEIA mentorship (NOT-OD-23- 002)” to the active R01 grant project (DE029709), entitled, “Role of OC-STAMP expressed on human osteoclasts in periodontitis”, proposes to develop a humanized mouse model of periodontitis to study the possible pathogenic roles of OC-STAMP expressed on human osteoclasts (OCs) in periodontitis lesion. The NSG-SGM3-W41 mouse strain which is one of the most advanced immunodeficient mouse strains developed by Dr. Shultz at the Jackson Laboratory allows us to reconstruct the full immune compartments containing both myeloid and lymphoid cell populations following transplantation of human hematopoietic stem cells (hHSC) without conditioning by irradiation. Recent study using humanized NSG mice showed that human OCs which are monocyte linage cells derived from hHSCs can be detected in the surrogate body of NSG mice. Relevant to parent R01 grant project, we preliminary discovered that, P. gingivalis (Pg), the keystone pathogen of periodontitis, increases the expression of OC-STAMP by human OC precursor cells. Since mouse lymphocytes don’t mount pathogenic immune response to orally inoculated Pg, it is argued that human lymphocytes which are under the control of mouse MHC-II in the humanized mice may not produce sufficient amount of RANKL to cause periodontitis in the humanized immunodeficient mice. However, we found that periodontal bone loss and local production of RANKL can be induced by ligature attachment to RAG1 immunodeficient mice, indicating that lymphocytes are not the major cellular source of RANKL in ligature-induced mouse periodontitis. Furthermore, because OC-STAMP is distinctively expressed by OCs and OC precursors, but not other lymphocytes derived from hHSCs, the anti-OC-STAMP Ab administered to humanized mice are expected to act on only human OCs. We hypothesize that Pg-dependently upregulated OC-STAMP expression by human OCs may promote the pathogenic bone resorption in the humanized mice indicative of periodontitis. This hypothesis will be tested by following two aims: 1) To examine the effects of anti-OCST Ab on the onset and progression of periodontitis induced in humanized mice with or without Pg inoculation, and 2) to determine the ligand of human OC-STAMP that promote the RANKL-induced OC-genesis in human OCs. Upon successful completion of this proposed study, it is anticipated that the roles of human OC-STAMP expressed by human OCs in periodontitis will be determined. This humanized mouse model of periodontitis would provide a platform for understanding the physiological context of molecules expressed on human OCS.