Role of propionibacteria in sarcoidosis

描述（由申请人提供）： 本提案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因学意义（目的1），并使用该细菌建立结节病小鼠模型（目的2）。几条证据表明，这种厌氧菌可能参与疾病的发病机制。首先，通过培养和PCR在日本和欧洲患者的高比例结节病淋巴结中鉴定出丙酸杆菌，并且用原位分子探针检测结节病肉芽肿中的丙酸杆菌。其次，对这种生物体有效的抗生素在一小群皮肤结节病患者中显示出显着的疗效。最后，暴露于这种细菌的动物发展成类似于结节病的肉芽肿性炎症。在目标1中，我们将寻找丙酸杆菌的证据，通过进行定量PCR，与这种生物体的特异性探针，从石蜡包埋的样品通过激光捕获显微镜获得的肉芽肿的DNA。我们还将通过原位杂交寻找丙酸杆菌。最后，我们将尝试从接受诊断评估的患者的组织中培养微生物。将对急性消退和慢性持续性疾病患者的培养细菌进行表征，以观察细菌因素是否有助于临床表型。培养的细菌也将用于接种小鼠以产生动物模型。将在暴露于丙酸杆菌后评估几种不同品系小鼠中肉芽肿性炎症的开始、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。将评价多个器官，包括肺、淋巴结、肝、脾、心脏、脑和眼以及皮肤，以确定宿主因素或细菌因素是否对特定器官受累重要。未来的研究方向将包括一个安慰剂对照试验四环素类治疗结节病，如果丙酸杆菌被确定。

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.