Innate Immunity in Experimental Arthritis of Kininogen

描述（由申请人提供）： 类风湿性关节炎（RA）是一种免疫介导的家族性慢性复发性疾病，最终导致关节破坏。了解炎症介质是至关重要的，因为这些分子提供了特定的抑制剂和受体拮抗剂的药理学阻断的方法。最近的啮齿动物关节炎模型表明，细菌细胞壁聚合物可以在遗传易感的大鼠品系中诱导急性和慢性关节炎。胃肠外注射肽聚糖多糖复合物（PG-APS）可诱导全身炎症反应，包括糜烂性多关节炎、肝肉芽肿和贫血。我们已经表明，实验性炎症性关节炎与刘易斯大鼠体内激肽释放酶-激肽系统（KKS）的激活有关，并且在这些易感的刘易斯大鼠中选择性失活，但在抗性的布法罗大鼠中不失活。在PG-APS模型中，特异性激肽释放酶抑制剂可降低KKS活化和急性炎症变化（水肿、中性粒细胞浸润），并预防关节炎和全身并发症（脾肿大、肝肿大、白细胞增多和急性期反应）。我们现在关注先天免疫机制在啮齿类动物炎性关节炎模型中的作用，特别是KKS与单核细胞和中性粒细胞的相互作用导致细胞因子的释放。我们探索两个主要的假设，使用新的方法，这个实验室。首先，我们假设缺乏高分子量激肽原（HK），这是激活血浆激肽释放酶所必需的，是缓激肽释放的底物，并将调节急性和慢性关节炎和全身炎症产生的PG-APS在遗传易感的刘易斯大鼠。我们已经发现，这些大鼠有一个单一的点突变$511N导致N-糖基化，这增加了敏感性HK蛋白水解。我们将研究缓激肽和裂解HK（HKA）在刘易斯大鼠的加速释放的机制，将增加先天免疫系统，特别是巨噬细胞，刺激通过细胞受体缓激肽和HKA白细胞的炎症细胞因子的释放。我们将使用激肽原单点突变导致肝分泌阻滞和严重血浆缺乏的大鼠品系进一步探讨这一假设，我们将其置于易感的刘易斯基因型上。我们还将使用人类HLA-B27转基因大鼠作为“自发性”慢性关节炎的模型，我们将用针对HK的单克隆抗体治疗。其次，我们将比较刘易斯与费舍尔大鼠在PG-APS诱导的实验性关节炎和全身炎症期间的炎症程度，这些大鼠具有不同程度的激肽原裂解I。我们将测试通过重组HK多肽、合成肽或该蛋白的抗体（已知其抑制HK或HKa与白细胞的结合）调节炎症是否可以预防许多炎症变化。我们将研究HKA和缓激肽的作用，使用敲除它们的结合蛋白，uPAR和B2 R，在小鼠关节炎和全身炎症。如果这些方法导致关节炎和全身炎症的大幅减少，它可能导致控制风湿性疾病，副作用可能比目前的治疗方法更少。

DESCRIPTION (provided by applicant): Rheumatoid arthritis (RA) is an immtmologically mediated, familial, chronically relapsing disease eventually resulting in joint destruction. Understanding inflammatory mediators is critical because these molecules provide approaches for pharmacologic blockade by specific inhibitors and receptor antagonists. Recent rodent models of arthritis have shown that bacterial cell wall polymers can induce acute and chronic arthritis in genetically susceptible rat strains. Parenterally injected peptidoglycanpolysaccharide complexes (PG-APS) induce a systemic inflammatory response consisting of erosive polyarthritis, hepatic granulomas, and anemia. We have shown that experimental inflammatory arthritis is associated with in vivo activation of the kallikrein-kinln system (KKS) in Lewis rats and is selectively inactivated in these susceptible Lewis rats, but not in resistant Buffalo rats. A specific kallikrein inhibitor decreases both the KKS activation and acute inflammatory changes (edema, neutrophil infiltration) and prevented arthritis and the systemic complications (splenomegaly, hepatomegaly, leukocytosis and the acute phase reaction) in the PG-APS model. We now focus on the role of innate immune mechanisms in models of rodent inflammatory arthritis, specifically the interaction of the KKS with monocytes and neutrophils resulting in release of cytokines. We explore two major hypothesis-using approaches new to this laboratory. First, we hypothesize that the lack of high molecular weight kininogen (HK), which is required for activation of plasma kallikrein, is the substrate for release of bradykinin and will modulate the acute and chronic arthritis and systemic inflammation produced by PG-APS in genetically susceptible Lewis rats. We have found that these rats have a single point mutation $511N leading to N-glycosylation which increases the susceptibility of HK to proteolysis. We will examine the mechanisms by which accelerated release of bradykinin and cleaved HK (HKa) in Lewis rats will augment inflammatory cytokine release by the innate immune system, particularly macrophages, stimulated through cellular receptors for bradykinin and HKa on leukocytes. This hypothesis will be explored further using a rat line with a single point mutation in kininogen leading to a block in hepatic secretion and severe plasma deficiency, which we have placed onto the susceptible Lewis genotype. We will also use the human HLA-B27 transgenic rat as a model of "spontaneous" chronic arthritis, which we will treat with a monoclonal antibody to HK. Second, we will compare the degree of inflammation in Lewis vs. Fischer rats with variable degrees of kininogen cleavage I during experimental arthritis and systemic inflammation induced by PG-APS. We will test whether modulation of inflammation by] recombinant HK polypeptides, synthetic peptides, or antibodies to that protein, which are known to inhibit binding of HK or HKa to] leukocytes, can prevent many of the inflammatory changes. We will examine the role of HKa and bradykinin using knockouts of their binding proteins, uPAR and B2R, in murine arthritis and systemic inflammation. If these approaches result in a substantial decrease in arthritis and systemic inflammation, it could lead to the control of rheumatic diseases with potentially fewer side effects than current therapeutic approaches.