Investigating Mucosal Breaks in the Initiation and Progression of Rheumatoid Arthritis

类风湿关节炎(RA)是一种自身免疫性滑膜炎，影响世界人口的0.5%。RA是 以临床关节炎的间歇性发作为特征的，被认为部分是由抗- 瓜氨酸蛋白自身免疫反应。最适合发展的环境风险因素 RA包括吸烟和牙周病，这表明口腔粘膜是疾病的关键部位 入会仪式。然而，这些环境暴露导致类风湿关节炎发展的机制 而进展情况仍然知之甚少。我们已经制定了一项临床和技术方案 类风湿性关节炎患者重复采集家庭指棒血以进行纵向RNA测序 (RNAseq)。使用这种新的方法，我们最近发现了人类口腔粘膜特有的细菌 在抗CCP+RA患者的血液中，随后激活标志性B细胞免疫反应3周 之后，再于2周后进行临床病情活动。我们还研究了B细胞对 这些病原体。我们发现IgA血浆母细胞在临床前类风湿关节炎和 在已建立的RA中，随着一组不同的IgA/Ig G浆母细胞克隆家族的持续重新激活， 已建立的类风湿关节炎提示持续的粘膜驱动的生发中心反应。我们证明了 持续激活的IgA/G克隆家族编码的重组单抗 同时与人类瓜氨酸化抗原和瓜氨酸化口腔细菌亚型反应的抗体 在闪光之前的病人血液中被确认。我们预计RA浆母细胞单抗具有明显的 特异性，无论是单独的还是在免疫复合物中，都介导了不同的细胞反应的激活，这些细胞反应 促进类风湿关节炎的滑膜炎和组织破坏。这份R01提案将检验一种假设，即粘膜 Break触发浆母细胞反应，该反应编码与宿主交叉反应的抗细菌抗体 瓜氨酸抗原。我们进一步假设粘膜细菌诱导的ACPA激活细胞 反应，包括巨噬细胞肿瘤坏死因子的产生，网织和破骨细胞的激活，促进 类风湿关节炎的滑膜炎和关节组织破坏。目标1将确定对耀斑前反应的抗体谱系 类风湿关节炎患者的两个独立队列中的菌血症。AIM 2将鉴定RA浆母细胞IgA/G单抗 和血清，用于对来自龈下收集的细菌物种的瓜氨酸化异构体的反应。目标3 将表征牙周炎组织，以寻找RA相关自身免疫的证据。目标4将决定 交叉反应单抗单独或在免疫复合体中介导关节炎的机制。成功 将证明瓜氨酸化牙周细菌和粘膜破裂起着关键作用。 在调节类风湿关节炎暴发的过程中，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.