HO-1 and granuloma formation in TB pleurisy

描述（由申请人提供）：结核病在艾滋病患者中流行，结核分枝杆菌在肉芽肿中的定位不佳，感染范围广泛。肉芽肿是源自循环外周血单核细胞（PBMC）的富含单核细胞的细胞集合。针对病原体的经典反应是细胞保护基因的表达，包括血红素加氧酶-1 (HO-1)，它允许调节炎症反应并抑制细胞凋亡。单核细胞通过C-C趋化因子（主要是单核细胞趋化蛋白-1，MCP- 1）和单核细胞CCR2受体表达的相互作用被募集到结核感染部位。这一提议的假设是，HO-1在募集的单核巨噬细胞中的表达代表了一个关键的调控事件，参与了胸膜结核有效的抗分枝杆菌宿主防御。HO-1缺失通过改变导致细胞凋亡的信号通路和改变CCR2在外周血单核细胞（PBMC）和胸膜巨噬细胞（PM）上的体内表达，导致肉芽肿形成不良，从而增强胸膜巨噬细胞凋亡并阻碍分枝杆菌清除。我们在HO-1 -/-和HO-1 +/+小鼠中建立了胸膜结核模型，以评估HO-1介导的CR2受体对PBMC和胸膜巨噬细胞（PM）的调节。我们将在体内胸膜结核模型以及体外PBMC和诱导的胸膜巨噬细胞中评估我们的假设。我们的具体目的是：具体目的#1：在小鼠胸膜炎模型和体外实验中，评估对照组HO-1 +/+和HO-1 -/-小鼠外周血单核细胞和胸膜巨噬细胞的基因表达谱。具体目的#2：评估结核性胸膜炎胸膜间隙肉芽肿形成过程中HO-1在外周血单核细胞和胸膜巨噬细胞凋亡中的调节作用。特异性目的#3：探讨结核性胸膜炎胸膜间隙肉芽肿形成过程中HO-1对外周血单核细胞和胸膜巨噬细胞CCR2表达的调控作用。了解HO-1介导的巨噬细胞募集、滞留和凋亡调控导致肉芽肿形成的机制对胸膜肺结核患者的病理生理学至关重要，并将有助于开发增强宿主防御反应的治疗模式。公共卫生相关性：了解HO-1介导的巨噬细胞募集、滞留和凋亡调控导致肉芽肿形成的机制对胸膜肺结核患者的病理生理学至关重要，并将有助于开发增强宿主防御反应的治疗模式。

DESCRIPTION (provided by applicant): Tuberculosis is endemic among patients with AIDS and follows an aggressive course with poor localization of mycobacteria into granuloma and widespread infection. Granulomas are monocyte rich collections of cells which derive from the circulating peripheral blood monocyte (PBMC). A classical response against pathogens is the expression of cytoprotective genes including Heme-oxygenase-1 (HO-1) which allows for a regulated inflammatory response as well as inhibits apoptosis of cells. Monocytes are recruited to the site of tuberculous infection by the interaction of C-C chemokines, (mainly monocyte chemoattractant protein-1, MCP- 1) and monocyte expression of the CCR2 receptor. It is the hypothesis of this proposal that HO-1 expression in recruited monocyte-macrophages represents a critical regulatory event involved in effective anti-mycobacterial host defense in pleural tuberculosis. HO-1 depletion enhances pleural macrophage apoptosis and impedes mycobacterial clearance by causing alterations in the signaling pathways leading to apoptosis and by altering the in vivo expression of CCR2 on the peripheral blood mononuclear cells (PBMC) and pleural macrophage (PM) leading to poor granuloma formation. We have developed a model of pleural tuberculosis in HO-1 -/- and HO-1 +/+ mice to evaluate the HO-1 mediated regulation of the CR2 receptor on PBMC and pleural macrophages (PM). We will evaluate our hypothesis in our model of pleural tuberculosis in vivo as well as in vitro in PBMC and elicited pleural macrophages. Our specific aims are: Specific aim #1: To evaluate gene expression profiles in peripheral blood monocytes and pleural macrophages from control HO-1 +/+ and HO-1 -/- mice, treated with H37Rv, in a murine model of TB pleurisy and in vitro Specific aim #2: To evaluate the regulatory role of HO-1 in apoptosis of peripheral blood monocytes and pleural macrophages during granuloma formation in the pleural space in tuberculous pleurisy. Specific aim #3: To evaluate the regulatory role of HO-1 in the expression of CCR2 on peripheral blood monocytes and pleural macrophages during granuloma formation in the pleural space in tuberculous pleurisy. Understanding the mechanisms underlying HO-1 mediated regulation of macrophage recruitment, retention and apoptosis, leading to granuloma formation is critical to the pathophysiology of pleuro-pulmonary tuberculosis seen in patients and will help develop therapeutic modalities that augment host-defense responses. PUBLIC HEALTH RELEVANCE: Understanding the mechanisms underlying HO-1 mediated regulation of macrophage recruitment, retention and apoptosis, leading to granuloma formation is critical to the pathophysiology of pleuro-pulmonary tuberculosis seen in patients and will help develop therapeutic modalities that augment host-defense responses.