Innate immune signal transduction specificity in inflammatory disease

摘要 先天免疫系统识别并响应病原生物体。在这样做时， 系统负责启动细胞因子反应，旨在调整适应性免疫系统， 根除致病微生物这一过程必须严格监管，因为过多的活动可能导致 炎症性疾病。由于炎症性疾病的特征是先天免疫功能延长， 激活和细胞因子释放，控制先天免疫应答下调的机制 在限制炎症病理学方面至关重要。本研究旨在研究这一机制。 通过关注NOD 2蛋白（CARD 15基因）的信号转导机制和 NOD 2在启动和维持细胞因子应答中的作用。NOD 2蛋白是一种 许多炎性疾病，包括Blau综合征（一种家族性肉芽肿病）， 早发性结节病和15-20%的遗传性克罗恩病。NOD 2被激活以响应 细胞内暴露于革兰氏阳性菌和革兰氏阴性菌后，它有助于协调NF B 通过赖氨酸-63（K63）连接的多聚泛素化的一个新位点（K285）激活和细胞因子释放， IKK支架蛋白NEMO。我们最近扩展了这一发现，表明主要的细胞外 先天性免疫信号受体，Toll样受体（TLR），也需要K285 NEMO泛素化， 通过NF B正确发送信号。这项工作表明，调控的翻译后修饰对 IKK支架蛋白NEMO有助于协调细胞内和细胞外先天性 免疫途径，也有助于调节的身份，数量和持续时间的细胞因子， 发布这些发现还表明，对于NF B信号，多种先天免疫信号通路 NEMO上的翻译后修饰作为一个变阻器来控制NF B 活动因此，这些翻译后修饰也可以是靶向靶向的分子的靶标。 下调由NOD 2和其他先天免疫信号传导途径激活的NF B应答。的 这项研究的中心假设是NOD 2和TLR刺激的NF B激活的下调是 这是避免炎症病理的最重要因素。未能适当下调NF B反应 和协调之间的替代（MAP激酶）信号通路可能是基础， 炎症性疾病的病理生理学。对这些下调途径的研究可能会导致 本发明涉及关于这些疾病的病理生理学的新见解和新的可药用靶点， 帮助治疗这些疾病。为了开始解决这一重要问题，我们已经产生了大量的 初步数据。我们在NEMO上发现了一个新的先天免疫诱导磷酸化位点， 控制NEMO泛素化，因此控制最终的NF B激活。我们还发现了一个 信号通路通过一个意想不到的MAP 3 K，抑制NEMO泛素化和转移 从NF B活性到p38活性的先天免疫信号传导。本补助金申请的具体目的 确定先天免疫诱导的NF B活性的生化机制， 下调，以确定MEKK 4在决定先天免疫缺陷下游信号特异性中的功能。 免疫系统激活，并确定这些信号通路在免疫系统疾病的病理生理学中的作用。 炎症性疾病。条款摘要 作为人类，我们经常接触细菌、真菌和病毒， 必须对这些病原体做出反应，这样我们才不会被感染。响应之后 如果我们的免疫系统没有失去活性， 例如哮喘、炎性肠病、多发性硬化症和 动脉粥样硬化（心脏和血管疾病）。像这样的炎症性疾病 一个重要的原因发病率和死亡率在广泛的人口（婴儿） 老年人）。由于下调炎症反应的重要性， 身体已经发展出复杂的机制来抑制炎症 反应这项拨款申请旨在研究抑制这种现象的机制。 炎症反应和这种抑制机制是错误的， 炎症性疾病。这项工作旨在帮助确定炎症的原因， 疾病，旨在确定药物干预的新靶点， 使人衰弱的疾病

Abstract 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. Lay Summary 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.