Role of Innate Immune System in Pathogen Induced Chronic Inflammation

描述(申请人提供)：慢性炎症最终导致破坏性事件，导致显著的宿主病理，并与许多人类疾病有关，包括自身免疫性疾病、传染病、肿瘤疾病和炎性血管斑块堆积。致病菌肺炎衣原体和牙龈卟啉单胞菌可诱导慢性炎症反应，尽管这些病原体如何诱导和维持慢性炎症还没有很好的定义。P01的中心假说是病原体通过先天免疫识别调节炎症介质调节宿主免疫细胞功能，从而导致慢性炎症性疾病。为了验证这一假说，我们提出了以下目标：目的1.明确在内皮细胞、巨噬细胞和血小板中诱导炎症介质对牙龈假单胞菌和肺炎链球菌反应的信号通路。目的2.明确转录因子在牙周炎和肺炎克雷伯菌炎症反应中的作用。目的3.明确牙龈假单胞菌和肺炎衣原体通过这些途径刺激炎症介质对内皮细胞、血小板和巨噬细胞功能的调节作用。目的4.明确这些信号通路在牙龈假单胞菌和肺炎衣原体诱导的小鼠血栓形成和慢性炎症发病机制中的作用。以下项目提出了针对这些目标的详细研究：项目1--先天免疫和病原体诱导的炎症在血小板功能中的作用；项目2--针对肺炎衣原体急性和慢性感染的先天免疫防御。项目3--先天免疫、脂质信号和慢性感染。&项目4：牙龈假单胞菌引起慢性炎症的先天免疫机制。以下核心将为这些项目提供服务：A.行政核心、B.体外核心和C.动物核心。这些协作性和协同性研究将确定特定的先天免疫信号分子在牙龈假单胞菌和肺炎衣原体诱导的与慢性炎症过程相关的细胞炎症反应中的作用。此外，使用已定义的炎症动物模型，我们将确定这些先天免疫途径在体内炎症过程中的作用。深入了解特定的先天免疫信号通路在促炎介质表达和功能性免疫反应中的作用，将为慢性炎症性疾病的新疗法提供一条有希望的途径。 项目1：先天免疫和病原体诱导的炎症在血小板功能中的作用(弗里德曼，J) 项目1描述(由申请人提供)：虽然有证据表明慢性炎症和感染促进了斑块的形成，但急性感染与血小板依赖性血栓形成引起的不稳定冠状动脉和血管综合征的风险一过性增加五倍有关。虽然许多细菌菌株可以诱导血小板聚集，但细菌刺激血小板的机制研究还很少。在利用全面的微阵列分析的初步数据中，以及近2000名受试者的大型社区队列中，我们发现心血管疾病患者的血小板基因表达有明显的模式。虽然在血小板中检测到几种TLR，但TLR2和IL1R在心血管疾病患者中的表达尤其增加。重要的是，TLR在血小板中的功能是通过与TLR2配体孵育而建立起来的，并以剂量依赖的方式诱导血小板的激活和聚集。此外，我们还发现，在体内肺炎衣原体感染和牙龈假单胞菌孵育时，血小板功能和血小板-单核细胞/中性粒细胞结合增强。整个计划项目的中心假设是：“病原体通过先天免疫识别调节炎症介质调节宿主免疫细胞功能，从而导致慢性炎症性疾病”。项目1的中心假设是细菌通过先天免疫途径在血小板中介导血栓形成和炎症过程。为了研究这一假设，我们提出了以下目标： 目的1.探讨TLR2和IL-1R在肺炎衣原体和牙龈假单胞菌增强血小板功能中的作用。 目的2.明确肺炎衣原体和牙龈假单胞菌对依赖TLR2和IL1R的血小板信号通路和巨核细胞依赖的NFkappaB转录的调节作用。 目的3.明确TLR2和IL-1R在体内对肺炎衣原体和牙龈假单胞菌依赖的血栓形成的血小板特异性反应中的作用。

DESCRIPTION (provided by applicant): Chronic inflammation culminates in devastating events, results in significant host pathology, and is associated with a number of human diseases including autoimmune diseases, infectious diseases, neoplastic diseases, and inflammatory vascular plaque accumulation. The pathogenic bacteria Chlamydophila pneumoniae and Porphyromanas gingivalis induce a chronic inflammatory response, although how these pathogens induce and maintain chronic inflammation is not well defined. The central hypothesis of this P01 is that pathogen stimulation via innate immune recognition modulates inflammatory mediator regulation of host immune cell function resulting in chronic inflammatory disorders. To test this hypothesis we propose the following Aims: Aim 1. To define the signaling pathways by which inflammatory mediators are induced in response to P. gingivalis and C. pneumoniae in endothelial cells, macrophages, and platelets. Aim 2. To define the contribution of transcription factors in inflammatory responses to P. gingivalis and C. pneumoniae. Aim 3. To define how P. gingivalis and C. pneumoniae stimulation of inflammatory mediators via these pathways modulates endothelial cell, platelet and macrophage function. Aim 4. To define the role of these signaling pathways in the pathogenesis of P. gingivalis and C. pneumoniae induced thrombosis and chronic inflammation in a mouse model. The following Projects propose detailed studies to address these Aims: Project 1-The Role of Innate Immunity and Pathogen-Induced Inflammation in Platelet Function; Project 2-Innate Immune Defenses Against Acute and Chronic Infection with C. pneumoniae. Project 3- Innate Immunity, Lipid Signaling, and Chronic Infection. & Project 4- Innate Immune Mechanisms Involved in P. gingivalis-Induced Chronic Inflammation. The following Cores will service these Projects: A. Administrative Core, B. In Vitro Core, and C. Animal Core. These collaborative and synergistic studies will define the role of specific innate immune signaling molecules in P. gingivalis and C. pneumoniae induced inflammatory responses in cells relevant to chronic inflammatory processes. Furthermore, using defined animal models of inflammation we will characterize the roles of these innate immune pathways in inflammatory processes in vivo. Enhanced understanding of the roles of specific innate immune signaling pathways, which participate in proinflammatory mediator expression and functional immune responses will provide a promising avenue for novel therapies for chronic inflammatory disorders. PROJECT 1: THE ROLE OF INNATE IMMUNITY AND PATHOGEN-INDUCED INFLAMMATION IN PLATELET FUNCTION (FREEDMAN, J) PROJECT 1 DESCRIPTION (provided by applicant): While there is evidence that chronic inflammation and infection promotes plaque formation, acute infections are associated with a transient five-fold increased risk of unstable coronary and vascular syndromes caused by platelet dependent thrombosis. While many strains of bacteria induce platelet aggregation, the mechanisms by which bacteria stimulate platelets has had minimal investigation. In preliminary data utilizing comprehensive microarray analyses, and a large community cohort of almost 2,000 subjects, we found distinct patterns of platelet gene expression in patients with cardiovascular disease. While several TLRs were detected in platelets, the expression of TLR2 and IL1R in particular were increased in patients with cardiovascular disease. Importantly, the functionality of TLR in platelets was established as incubation of platelets with TLR2 ligands dose-dependently induced platelet activation and aggregation. In addition, we found enhanced platelet function and platelet-monocyte/neutrophil binding with C. pneumoniae infection in vivo, and P. gingivalis incubation. The central hypothesis of the overall program project is that "Pathogen stimulation via innate immune recognition modulates inflammatory mediator regulation of host immune cell function resulting in chronic inflammatory disorders". The central hypothesis of Project 1 is that bacteria mediate pro-thrombotic and -inflammatory processes in platelets via innate immune pathways. To investigate this hypothesis, we propose the following Aims: Aim 1. To define the role of TLR2 and IL-1R in C. pneumoniae and P. gingivalis enhanced platelet function. Aim 2. To define C. pneumoniae and P. gingivalis mediated modulation of TLR2- and IL1R-dependent signaling pathways in platelets and NFkappaB-dependent transcription in megakaryocytes. Aim 3. To define the role of TLR2 and IL-1 R in platelet specific responses to C. pneumoniae and P. gingivalis dependent thrombosis in vivo.