HLA-B27 and Experimental Spondyloarthropathy

描述（申请人提供）：IMHC类等位基因HLA-B27在强直性脊柱炎和相关疾病（脊柱关节炎，SpA）患者中的患病率较高。众所周知，B27通常是一种正常的免疫成分，它本身也参与SpA，但它是如何参与SpA的尚不清楚。SpA也与炎症性肠病（IBD）和细胞内细菌感染有关。我们的目标是确定B27如何导致SpA和慢性炎症。在本项目中，将在动物模型中追求这一目标。具有高转基因拷贝数和表达的B27转基因大鼠自发地发展类似于人类SpA的疾病（大鼠SpA），具有关节炎和结肠炎，而具有低B27或具有另一等位基因HLA-B7的高转基因含量的遗传上相同的大鼠保持健康。无菌B27大鼠保持健康。与人SpA一样，rSpA对抗TNF治疗有反应。已知在人细胞系和B27大鼠中，B27重链在白细胞的内质网内发生错误折叠，触发未折叠蛋白反应（UPR）并产生B27重链寡聚体。在具体目标I中，将检验B27的这种错误折叠和/或UPR过程参与rSpA发病机制的假设。几种可能的机制，这将通过各种生物化学和遗传学的方法进行调查。将测试B27本身或随后的UPR是否：[1]改变Toll样受体或IBD相关的Nod 2蛋白的细菌传感; [2]触发一个或多个导致树突状细胞功能障碍的途径; [3]改变细胞内细菌入侵激活的途径; [4]引起关键细胞的不适当凋亡; [5]引起细胞凋亡。[5]导致β 2-微球蛋白沉积和随后的关节炎。所有这些发现将与各种转基因系的临床结果相关。在特定目标II中，将检验经典假设，即疾病是由B27的肽呈递引起的。将具有最近产生的CDS无效突变体的大鼠与B27大鼠杂交，以评估干扰I类MHC的T细胞识别对rSpA的影响。在这两个具体目标的研究结果将通过实验进行后续研究，以产生更多相关的转基因和基因敲除大鼠。总的来说，该项目应有助于解决有关HLA-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。

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.