Innate immune signal transduction specificity in inflammatory disease

炎症性疾病中的先天免疫信号转导特异性

• 批准号: 8126597
• 负责人: Derek W Abbott
• 金额: $ 7.14万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8126597
• 关键词: Applications Grants; Asthma; Atherosclerosis; Bacteria; Biochemical; Cardiovascular system; Crohn' s disease; Cytokine Activation; Data; Disease; Down-Regulation; Elderly; Exposure to; Failure; Functional disorder; Genes; Genetic; Gram-Negative Bacteria; Grant; Human; Immune; Immune response; Immune system; Infant; Inflammatory; Inflammatory Bowel Diseases; Inflammatory Response; Intervention; Lead; Link; Lysine; MAP Kinase Signaling Pathways; MAPK14 gene; Morbidity - disease rate; Multiple Sclerosis; Organism; Pathology; Pathway interactions; Pharmacologic Substance; Phosphorylation; Phosphorylation Site; Polyubiquitination; Population; Post-Translational Protein Processing; Process; Proteins; Receptor Signaling; Regulation; Role; Sarcoidosis; Scaffolding Protein; Serine; Signal Pathway; Signal Transduction; Site; Specificity; Syndrome; System; Toll-like receptors; Ubiquitination; Vascular Diseases; Virus; Work; cytokine; design; early onset; extracellular; fungus; immune activation; insight; mortality; novel; pathogen; public health relevance; response

DESCRIPTION (provided by applicant): The innate immune system recognizes and responds to pathogenic organisms. In doing so, this system is responsible for initiating a cytokine response designed to tailor the adaptive immune system to eradicate the offending organism. This process must be tightly regulated as too much activity can lead to inflammatory disease. Because inflammatory diseases are characterized by prolonged innate immune activation and cytokine release, the mechanisms controlling downregulation of the innate immune response are paramount in limiting inflammatory pathology. This grant application aims to study the mechanisms of this downregulation by focusing on the signal transduction mechanisms of NOD2 protein (CARD15 gene) and on NOD2's role in initiating and maintaining the cytokine response. The NOD2 protein is responsible for a number of inflammatory disorders including Blau Syndrome (a familial granulomatosis disease), a subset of Early Onset Sarcoidosis and for 15-20% of genetic Crohn's Disease. NOD2 is activated in response to intracellular exposure to both gram-positive and gram-negative bacteria after which it helps to coordinate NF-?B activation and cytokine release through the lysine-63 (K63)-linked polyubiquitination of a novel site (K285) on the IKK scaffolding protein NEMO. We have recently extended this finding to show that the major extracellular innate immune signaling receptors, the Toll-like Receptors (TLRs), also require K285 NEMO ubiquitination to properly signal through NF-?B. This work suggests that regulation of the post-translational modifications on the IKK scaffolding protein, NEMO, helps to coordinate cross-talk between intracellular and extracellular innate immune pathways and also helps to regulate the identity, the amount and the duration of cytokines that are released. These findings also suggest that for NF-?B signaling, multiple innate immune signaling pathways converge on NEMO and that the post-translational modifications on NEMO serve as a rheostat to control NF-?B activity. As such, these post-translational modifications may also be targets for molecules aimed at downregulating the NF-?B response activated by NOD2 and other innate immune signaling pathways. The central hypothesis of this grant is that downregulation of NOD2 and TLR-stimulated NF-?B activation is paramount in avoiding inflammatory pathology. Failure to properly downregulate the NF-?B response and coordinate between alternative (MAP kinase) signaling pathways may underlie the pathophysiology of inflammatory disorders. Study of these pathways of downregulation could lead both to novel insight regarding the pathophysiology of these diseases and to novel druggable target to help treat these diseases. To begin to tackle this important problem, we have generated significant preliminary data. We have identified a novel innate immune-induced phosphorylation site on NEMO that controls NEMO ubiquitination and therefore, controls ultimate NF-?B activation. We have also identified a signaling pathway operating through an unexpected MAP3K which inhibits NEMO ubiquitination and shifts innate immune signaling from NF-?B activity toward p38 activity. The Specific Aims of this grant application aim to determine the biochemical mechanisms by which innate immune-induced NF-?B activity can be downregulated, to determine the function of MEKK4 in dictating signal specificity downstream of innate immune system activation and to determine the role of these signaling pathways in the pathophysiology of inflammatory disease. Public Health Relevance: As humans, we are constantly exposed to bacteria, fungi and viruses, and we must respond to these pathogens so that we do not become infected. After responding to these pathogens, if our immune systems do not deactivate, we develop inflammatory disorders such as asthma, inflammatory bowel disease, multiple sclerosis and atherosclerosis (heart and vascular disease). Inflammatory diseases such as these are a significant cause of morbidity and mortality across a wide range of populations (infants to elderly). Due to the importance of downregulating the inflammatory response, our bodies have developed sophisticated mechanisms to dampen the inflammatory response. This grant application aims to study the mechanisms that dampen this inflammatory response and the mechanisms by which this dampening is faulty in inflammatory disease. This work aims to help determine the causes of inflammatory disease and aims to identify novel targets for pharmaceutical intervention in these debilitating disorders.

描述（由申请人提供）：先天免疫系统识别并应对病原生物。这样一来，该系统负责启动细胞因子反应，旨在量身定制自适应免疫系统以消除违规生物。必须严格调节此过程，因为过多的活动会导致炎症性疾病。由于炎症性疾病的特征是延长先天免疫激活和细胞因子释放，因此控制先天免疫反应下调的机制在限制炎症病理学方面至关重要。该赠款应用旨在通过关注NOD2蛋白（Card15基因）的信号转导机制以及NOD2在启动和维持细胞因子反应中的作用来研究这种下调的机制。 NOD2蛋白负责多种炎症性疾病，包括BLAU综合征（一种家族性肉芽肿病），一部分早期发作结节病和15-20％的遗传性克罗恩病。 NOD2因细胞内暴露于革兰氏阳性和革兰氏阴性细菌而受到激活，然后通过赖氨酸63（K63）链接的多泛素化在IKK蛋白质Nemo上通过赖氨酸63（K63）连接的多泛素化来协调NF-？B激活和细胞因子释放。我们最近扩展了这一发现，以表明主要的细胞外免疫信号受体，Toll样受体（TLR）也需要K285 Nemo泛素化来通过NF- b正确信号。这项工作表明，对IKK脚手架蛋白Nemo的翻译后修饰进行调节，有助于协调细胞内和细胞外的先天免疫途径之间的串扰，并有助于调节被释放的细胞因子的身份，量和持续时间。这些发现还表明，对于NF-？B信号传导，多个先天免疫信号通路会在Nemo上汇聚，并且对NEMO的翻译后修饰是控制NF-？B活性的变阻器。因此，这些翻译后修饰也可能是旨在下调NF-？b反应被NOD2和其他先天免疫信号通路激活的分子的靶标。该赠款的中心假设是NOD2和TLR刺激的NF-？B激活的下调至关重要。无法正确下调替代性（MAP激酶）信号通路之间的NF- b反应并坐标可能是炎症性疾病的病理生理的基础。对这些下调途径的研究可能会导致有关这些疾病的病理生理学的新洞察力，也可以引起可帮助治疗这些疾病的新型可药物靶标。为了开始解决这个重要问题，我们产生了大量的初步数据。我们已经确定了NEMO上的新型先天免疫诱导的磷酸化位点，该位点控制了Nemo泛素化，因此控制了最终的NF-？B激活。我们还确定了通过意外MAP3K运行的信号通路，该途径抑制了Nemo泛素化，并将先天的免疫信号从NF-？B活性转移到p38活性。该赠款应用的具体目的旨在确定可以下调先天免疫引起的NF-？B活性的生化机制，以确定MEKK4在决定先天免疫系统激活下游的信号特异性并确定这些信号途径在炎症疾病病理学中的作用的功能。 公共卫生的相关性：作为人类，我们不断接触细菌，真菌和病毒，我们必须对这些病原体做出反应，以免被感染。在对这些病原体作出反应后，如果我们的免疫系统不失活，我们会发展出炎症性疾病，例如哮喘，炎症性肠病，多发性硬化症和动脉粥样硬化（心脏和血管疾病）。诸如此类的炎症性疾病是广泛种群（婴儿到老年人）的发病率和死亡率的重要原因。由于下调炎症反应的重要性，我们的身体已经开发出抑制炎症反应的复杂机制。该赠款的应用旨在研究抑制这种炎症反应的机制以及这种抑郁症在炎症性疾病中的机制。这项工作旨在帮助确定炎症性疾病的原因，并旨在确定这些令人衰弱的疾病中药物干预的新目标。