Defining Microbial and Host Factors in Innate Immune Responses in Lyme Arthritis

描述(申请人提供)：莱姆病已经达到流行的程度，并继续在美国东北部的某些地方传播。该地区受到一种特别具有炎症性的伯氏杆菌基因RST1(OspC Type A)的影响，该基因已被证明在扁虱中有很高的传播频率，并可能是20世纪末美国东北部以流行形式出现莱姆病的主要原因。然而，伯氏杆菌螺旋体不包含任何已知的引起毒力的毒素。相反，感染后发生的疾病与螺旋体刺激的炎性免疫反应类型有关，TLR1(1805GG)基因的单核苷酸多态进一步增强了这种反应，该基因存在于大约一半的欧洲高加索人中。为了评估这些微生物和宿主因素在莱姆关节炎先天免疫反应中的作用，我们建议：1.使用基于微珠的Luminex分析，比较来自具有或不具有1805GG多态的正常捐赠者的单个细胞类型的巨噬细胞中的细胞因子和趋化因子的反应，这些细胞受到高度炎症的RST1(OspC A型)菌株或炎症较轻的RST2(OspC类型K)菌株的刺激，2.通过使用全基因组微阵列测量细胞基因的激活，识别巨噬细胞用来感知和响应OspC A或K菌株的信号转导网络，并评估1805GG TLR1多态如何改变这些网络，3.利用RNA干扰试剂抑制TLR11805GG多态改变巨噬细胞培养系统炎症反应的候选基因，以明确基因芯片识别的通路的功能后果。抗生素难治性莱姆关节炎可能至少在一定程度上是一种巨噬细胞不适当激活的综合征，涉及微生物和宿主遗传。巨噬细胞也与其他风湿性疾病的发病机制有关，包括类风湿性关节炎，其滑膜病变类似于抗生素耐药的莱姆关节炎患者。因此，这里开发的有针对性的方法，描述抗生素难治性莱姆关节炎中巨噬细胞不适当激活的潜在机制，将有助于理解先天免疫性炎症反应如何导致其他炎症性和风湿性疾病(包括类风湿性关节炎)关节中自身免疫的发展。 公共卫生相关性：这里提出的研究旨在描绘特定的宿主和病原体相互作用如何引发炎性先天免疫反应的类型，这些反应塑造了假定的自身免疫现象的发展，并导致更严重的疾病。我们相信，提案中使用的新的、基于发现的方法将为抗生素难治性莱姆关节炎的发病机制提供重要的新见解，并可能 对其他形式的慢性炎症性关节炎具有重要的临床相关性，特别是在那些感染因素和不适当的天然免疫系统激活可能起作用的情况下。

DESCRIPTION (provided by applicant): Lyme disease has reached epidemic proportions and continues to spread in certain locations in the northeastern U.S. This region is affected by an especially inflammatory B. burgdorferi genotype, RST1 (OspC Type A) which has been shown to have a high transmission frequency among ticks, and may be primarily responsible for the emergence of Lyme disease in epidemic form in the northeastern U.S. in the late 20th century. However, B. burgdorferi spirochetes do not contain any known toxins that cause virulence. Rather, the disease that ensues following infection is related to the type of inflammatory immune responses that are stimulated by the spirochetes, and that are further augmented by a single nucleotide polymorphism in the TLR1 (1805GG) gene which is present in about half of the European Caucasians. To assess the role of these microbial and host factors in innate immune responses in Lyme arthritis we propose: 1. to compare cytokine and chemokine responses in macrophages, a single cell type, from normal donors with or without the 1805GG polymorphism, stimulated with a highly inflammatory RST1 (OspC type A) strain or a less inflammatory RST2 (OspC type K) strain, using bead-based Luminex assays, 2. to identify the signal transduction networks used by macrophages to sense and respond to OspC type A or K strains and to assess how the 1805GG TLR1 polymorphism alters these networks, by measuring the activation of cellular genes using genome-wide microarrays, and 3. to discern the functional consequences of pathways identified by gene microarrays using RNA interference reagents to inhibit candidate genes by which the TLR1 1805GG polymorphism alters the inflammatory response in our macrophage culture system. Antibiotic-refractory Lyme arthritis may be, at least in part, a syndrome of inappropriate macrophage activation involving both microbial and host genetics. Macrophages are also implicated in the pathogenesis of other rheumatic diseases including RA in which the synovial lesions are similar to those in patients with antibiotic-refractory Lyme arthritis. Thus, it is likely that the targeted approach developed here, to delineate mechanisms underlying inappropriate macrophage activation in antibiotic-refractory Lyme arthritis, will be valuable in understanding how innate immune inflammatory responses may lead to development of autoimmunity in the joint in other inflammatory and rheumatic diseases, including RA. PUBLIC HEALTH RELEVANCE: The studies proposed here are aimed at delineating how specific host and pathogen interactions elicit the type of inflammatory innate immune responses that shape the development of putative autoimmune phenomena and lead to more severe disease. We believe the novel, discovery- based approach used in the proposal will provide important new insight into the pathogenesis of antibiotic-refractory Lyme arthritis and will likely be of significant clinical relevance to other forms of chronic inflammatory arthritis particularly those in which infectious agents and inappropriate innate immune system activation may play a role.