HLA-B27 and Experimental Spondyloarthropathy

描述(申请人提供)：在强直性脊柱炎和相关疾病(脊柱关节炎，SpA)的患者中，发现类IMHC等位基因人类白细胞抗原-B27的高患病率。众所周知，B27通常是一种正常的免疫成分，它本身也参与SPA，但它是如何做到这一点的尚不清楚。SPA还与炎症性肠病(IBD)和细胞内细菌感染有关。我们的目标是确定B27是如何导致温泉和慢性炎症的。在这个项目中，这一目标将通过动物模型来实现。具有高转基因拷贝数和高表达的B27转基因大鼠会自发地患上类似于人类SpA的疾病(大鼠SpA)，并伴有关节炎和结肠炎，而B27低或另一等位基因HLA-B7的转基因含量高的基因相同的大鼠则保持健康。无菌B27大鼠保持健康。与人类SPA一样，RSPA对抗肿瘤坏死因子治疗也有反应。已知在人类细胞系和B27大鼠中，B27重链在白细胞内质网内发生错误折叠，触发未折叠蛋白反应(UPR)，产生B27重链寡聚体。在特定的目标I中，将检验B27的这种错误折叠和/或UPR过程参与RSPA的发病机制的假设。将通过各种生化和遗传方法研究这一现象的几种可能机制。还将测试B27本身或随后的UPR：[1]改变Toll样受体或IBD相关NOD2蛋白的细菌感知；[2]触发一个或多个导致树突状细胞功能障碍的途径；[3]改变由细胞内细菌入侵激活的途径；[4]导致关键细胞不适当的凋亡；[5]导致p2-微球蛋白沉积和随后的关节炎。所有这些发现都将与不同转基因品系的临床结果相关。在特定目标II中，将检验经典假设，即疾病是由B27呈递的多肽引起的。最近产生CDS缺失突变的大鼠将与B27大鼠杂交，以评估干扰MHC I类T细胞识别对RSPA的影响。这两个特定目的的结果将通过实验进行跟踪，以产生更多相关的转基因和基因敲除大鼠。总体而言，该项目应该对解决有关人类白细胞抗原-B27和先天免疫在慢性炎症性疾病中的作用的几个重要问题做出实质性贡献。

DESCRIPTION (provided by applicant): The class IMHC allele HLA-B27 is found with high prevalence in patients with ankylosing spondylitis and related diseases (spondyloarthritis, SpA). It is known that B27, ordinarily a normal immune component, itself participates in SpA, but how it does so is unknown. SpA is also associated with inflammatory bowel disease (IBD), and with intracellular bacterial infection. Our goal is to identify how B27 causes SpA and chronic inflammation. In this project this goal will be pursued in an animal model. B27 transgenic rats with a high transgene copy number and expression spontaneously develop a disease (rat SpA) that resembles human SpA, with arthritis and colitis, whereas genetically identical rats with low B27, or with high transgene content of another allele, HLA-B7, remain healthy. Germfree B27 rats remain healthy. Like human SpA, rSpA responds to anti-TNF therapy. It is known that in human cell lines and in the B27 rats that B27 heavy chain undergoes misfolding within the endoplasmic reticulum of leukocytes, triggering the unfolded protein response (UPR) and creating B27 heavy chain oligomers. In Specific Aim I, the hypothesis will be tested that this misfolding and/or UPR process of B27 participates in the pathogenesis of rSpA. Several possible mechanisms for this will be investigated through a variety of biochemical and genetic approaches. It will be tested whether B27 itself, or the subsequent UPR: [1] alters bacterial sensing by Toll-like receptors or the IBD-associated Nod2 protein; [2] triggers one or more pathways that cause dysfunction of dendritic cells; [3] alters the pathways activated by intracellular bacterial invasion; [4] cause inappropriate apoptosis of critical cells; [5] causes deposition of p2-microglobuin and subsequent arthritis. All of these findings will be correlated with the clinical outcome in the various transgenic lines. In Specific Aim II, the classical hypothesis will be tested that disease results from peptide presentation by B27. Rats with a recently produced CDS null mutant will be crossed with B27 rats to assess the effect on rSpA of interfering with T cell recognition of MHC class I. Findings in both specific aims will be followed up by experiments to produce additional relevant transgenic and knockout rats. Overall, the project should contribute substantially to resolving several important issues about the role of HLA-B27 and innate immunity in chronic inflammatory disease.