Investigating Mucosal Breaks in the Initiation and Progression of Rheumatoid Arthritis

风湿性关节炎（RA）是一种自身免疫性滑膜炎，影响世界人口的0.5%。RA是 其特征在于临床关节炎的间歇性发作，其被认为部分由抗- 瓜氨酸蛋白自身免疫反应。发展中国家的最佳环境风险因素 RA包括吸烟和牙周病，表明口腔粘膜是疾病的关键部位 入会仪式然而，这些环境暴露导致RA发展的机制 和进展仍然知之甚少。我们已经建立了一个临床和技术协议， 在RA患者中重复家庭手指针刺采血以允许纵向RNA测序 （RNAseq）。利用这种新方法，我们最近发现了人类口腔粘膜的细菌特征， 在抗CCP + RA患者的血液中，随后激活标志性B细胞免疫应答3周 之后，然后在2周后出现疾病活动的临床发作。我们还研究了B细胞对 这些病原体。我们证实了临床前RA和RA患者伊加浆母细胞的升高， 在已建立的RA中，随着一组独特的伊加/IgG浆母细胞克隆家族的持续重新激活， 建立了RA，表明持续的粘膜驱动的生发中心反应。我们证明了 由持续再活化的伊加/G浆母细胞克隆家族编码的重组单克隆抗体编码 与人瓜氨酸化抗原和口腔细菌的瓜氨酸化同种型反应的抗体 在发作前的患者血液中发现。我们预期RA浆母细胞单克隆抗体具有不同的 特异性，无论是单独或在免疫复合物中，介导不同细胞反应的激活， 促进RA中的滑膜炎和组织破坏。本R 01提案将检验粘膜 断裂触发浆母细胞应答，浆母细胞应答编码与宿主交叉反应的抗菌抗体 瓜氨酸化抗原。我们进一步假设，粘膜细菌诱导的ACPA激活细胞 反应，包括巨噬细胞TNF产生，NETosis和破骨细胞活化，这促进了 滑膜炎和关节组织破坏。目的1将确定对预爆发有反应的抗体库 两个独立的RA患者队列中的菌血症。目的2将表征RA浆母细胞伊加/G单克隆抗体 以及血清对来自龈下收集物的细菌物种的瓜氨酸化同种型的反应性。目标3 将表征牙周炎组织中RA相关自身免疫的证据。目标4将决定 交叉反应性单克隆抗体单独或以免疫复合物形式介导关节炎的机制。成功 这一提议的结果将证明瓜氨酸化牙周细菌和粘膜破损发挥关键作用， 在介导类风湿性关节炎发作，发现可能导致新的诊断和治疗方法的发展。

Rheumatoid arthritis (RA) is an autoimmune synovitis that affects 0.5% of the world population. RA is characterized by intermittent flares of clinical arthritis that is thought to be mediated in part by anti- citrullinated protein autoimmune responses. The best established environmental risk factors for developing RA include cigarette smoking and periodontal disease, suggesting oral mucosa is a critical site for disease initiation. Nevertheless, the mechanisms by which these environmental exposures lead to RA development and progression remain poorly understood. We have established a clinical and technical protocol for repeated home finger stick blood collection in RA patients to allow for longitudinal RNA sequencing (RNAseq). Using this novel approach, we recently discovered bacteria characteristic of human oral mucosa in the blood of anti-CCP+ RA patients, followed by activation of a signature B cell immune response 3 weeks later, and then clinical flare of disease activity 2 weeks after that. We also investigated B cell responses to these pathogens. We demonstrated elevations in IgA blood plasmablasts both in pre-clinical RA as well as in established RA, with the continual re-activation of a distinct set of IgA/IgG plasmablast clonal families in established RA suggesting a persistent mucosally-driven germinal center reaction. We demonstrate that the recombinant Mabs encoded by the persistently reactivated IgA/G plamablast clonal families encode antibodies that react with both human citrullinated antigens and citrullinated isoforms of oral bacteria identified in the blood of patients antecedent to flares. We anticipate that RA plasmablast Mabs with distinct specificities, either alone or in immune complexes, mediate activation of distinct cellular responses that promote synovitis and tissue destruction in RA. This R01 proposal will test the hypothesis that mucosal breaks trigger plasmablast responses that encode anti-bacterial antibodies that cross-react with host citrullinated antigens. We further hypothesize that mucosal bacteria-induced ACPA activate cellular responses, including macrophage TNF production, NETosis and osteoclast activation, which promote synovitis and joint tissue destruction in RA. Aim 1 will identify the antibody repertoires responsive to pre-flare bacteremia in two independent cohorts of RA patients. Aim 2 will characterize RA plasmablast IgA/G Mabs and sera for reactivity to citrullinated isoforms of bacterial species derived from subgingival collections. Aim 3 will characterize periodontitis tissue for evidence of RA-related autoimmunity. Aim 4 will determine the mechanisms by which cross reactive Mabs, either alone or in immune complexes, mediate arthritis. Success of this proposal would demonstrate that citrullinated periodontal bacteria and mucosal breaks play a key role in mediating RA flare, findings that could lead to development of new diagnostic and therapeutic approaches.