Role of propionibacteria in sarcoidosis

描述(由申请人提供)： 这项建议的目的是确定丙酸杆菌是否对美国结节病的发生具有重要的病原学意义(目标1)，并利用这种细菌建立结节病的小鼠模型(目标2)。一些证据表明，这种厌氧细菌可能参与了疾病的发病机制。首先，通过培养和聚合酶链式反应在日本和欧洲患者的高比例结节状淋巴中鉴定出丙酸杆菌，并用原位分子探针研究在结节状肉芽肿中发现丙酸菌。其次，对这种细菌有效的抗生素在一小部分皮肤结节病患者中显示出显著的效果。最后，暴露在这种细菌下的动物会出现类似于结节病的肉芽肿性炎症。在目标1中，我们将通过对石蜡包埋样品的激光捕获显微镜获得的肉芽肿DNA进行定量聚合酶链式反应(针对这种细菌的探针)来寻找丙酸杆菌的证据。我们还将通过原位杂交寻找丙酸菌。最后，我们将尝试从接受诊断评估的患者的组织中培养出生物体。培养的细菌将从急性缓解和慢性迁延性疾病的患者身上鉴定，看看细菌因素是否对临床表型有贡献。培养的细菌还将用于接种小鼠，以产生动物模型。暴露于丙酸菌后，将评估几种不同品系小鼠肉芽肿性炎症的启动、维持和消退。这些实验将使我们能够将宿主因素视为临床表型的决定因素。将对多个器官进行评估，包括肺、淋巴结、肝、脾、心、脑、眼和皮肤，以确定宿主因素或细菌因素对特定器官的影响是否重要。未来的方向将包括四环素类药物治疗结节病的安慰剂对照试验，如果发现丙酸菌的话。

DESCRIPTION (provided by applicant): The objective of this proposal is to determine if Propionibacteria are etiologically important to the development of sarcoidosis in the United States (Aim 1), and to develop a mouse model of sarcoidosis using this bacterium (Aim 2). Several lines of evidence suggest that this anaerobic bacteria may be involved in the pathogenesis of disease. First Propionibacteria have been identified by culture and PCR in a high percentage of sarcoid lymph nodes from Japanese and European patients, and studies with in situ molecular probes detected Propionibacteria within sarcoid granulomas. Second, antibiotics effective against this organism showed remarkable efficacy in a small group of patients with cutaneous sarooidosis. Finally, animals exposed to this bacterium develop granulomatous inflammation similar to sarcoidosis. In Aim 1 we will look for evidence of Propionibacteria by performing quantitative PCR, with probes specific for this organism, on DNA from granulomas obtained by laser capture microscopy from parffin-embedded samples. We will also look for Propionibacteria by in situ hybridization. Finally, we will attempt to culture the organism from tissue obtained from patients undergoing diagnostic evaluation. Cultured bacteria will be characterized from patients with acute-resolving and chronic-persistent disease to see if the bacterial factors contribute to clinical phenotype. Cultured bacteria will also be used for inoculation in mice to produce an animal model. The initiation, maintenance, and resolution of granulomatous inflammation in mice of several different strains will be assessed following exposure to Propionibacteria. These experiments will allow us to look at host factors as determinants of clinical phenotype. Multiple organs will be evaluated including the lungs, lymph nodes, liver, spleen, heart, brain, and eyes, and skin to determine whether host factors or bacterial factors are important for specific organ involvement. Future directions will include a placebo-controlled trial of tetracyclines for sarcoidosis if Propionibacteria are identified.