Intracellular immunity, cytosolic DNA sensing by cyclic GAMP synthase, and macrophages in ischemic injury and cardiac remodeling

项目摘要/摘要 靶向白介素1β抑制动脉壁炎症可降低心血管疾病的发生率 事件。然而，我们还没有发现限制急性缺血时炎症相关损伤的策略。一 主要障碍是在理解危险识别方面的关键知识差距，即 决定了炎症的范围。我的长期目标是开发免疫调节剂来改变危险 认识到心肌梗死后含有炎症介导的损伤。这项提议的总体目标是 确定DNA及其胞质受体环磷酸腺苷合成酶(CGAS)如何传播由 缺血症。受损的心肌富含线粒体(每个心肌细胞有数千个拷贝) 和核DNA。大量DNA对心肌修复构成严重威胁，巨噬细胞， 专业的吞噬细胞，检测到它并做出强有力的炎症反应 意在消除病原体(从进化的角度来看)。中心假设是认识到 CGAS介导的DNA通过激活I型干扰素途径支持炎性巨噬细胞 促进炎症激素的激活；因此，cGAS在缺血诱导的重塑中起关键作用。这一假设已经 是根据我的实验室的初步数据和最近发表的工作制定的。理由是 了解缺血引发的炎症中的细胞内危险识别有可能发现 限制炎症相关损伤的有效方法。在强劲的初步数据的指引下，这一假设将得到检验 通过追求以下特定目标：1)确定巨噬细胞中cGAS的激活是否会导致缺血- 2)确定cGAS是否持续 促进AIM2和NLRP3炎症小体和caspase 11介导的巨噬细胞炎症 3)寻找抑制cGAS的有效和临床相关的方法。目标1将是 使用cGASf/f小鼠系确定巨噬细胞为负责细胞类型。研究也在进行 用来追踪胞浆DNA的来源。在第二个目标下，我将确定是否有后期结合的鸟粪 由cGAS激活诱导的蛋白质(GBP)增加了对AIM2和NLRP3等传感器的危险信号可见性 如果cGAS依赖，启动在cGAS触发的缺血炎性小体激活中是必不可少的。下垂- 由caspase 11介导的也将被评估。目标3将确定抑制cGAS的临床相关策略 通过评估两种治疗炎症性疾病的药物。这项以DNA为靶点的研究在概念上是新颖的 和它的受体cGAS，在心肌缺血的情况下，一种真正的抗病毒反应。知识 获得性免疫将在纵向上促进我们对细胞内免疫在缺血性损伤中的关键作用的理解。AS 缺血性心脏病是一种巨大的负担，往往是一种毁灭性的疾病，这项拟议的研究推动了这一领域的发展 通过寻找新的战略来减轻负担和改善护理。此外，结果将有助于理解 通过增强cGAS-STING途径活性进行免疫治疗的潜在心脏副作用(在临床试验中)。

PROJECT SUMMARY/ABSTRACT Inhibiting inflammation of the arterial wall by targeting interleukin-1β lowers the incidence of cardiovascular events. However, we have not discovered strategies limiting inflammation-related injury in acute ischemia. One major obstacle is the critical gap of knowledge in understanding danger recognition, the actual process that dictates the scope of inflammation. My long-term goal is to develop immune modulators that modify danger recognition to contain inflammation-mediated injury after MI. The overall objective of this proposal is to determine how DNA and its cytosolic receptor the cyclic GAMP synthase (cGAS) propagate injury triggered by ischemia. The damaged myocardium is enriched with mitochondrial (thousands of copies per cardiomyocyte) and nuclear DNA. The large amount of DNA poses a serious threat to myocardial repair when macrophages, the professional phagocytes, detect it and respond with robust inflammatory responses that are originally intended to get rid of pathogens (from the evolutionary standpoint). The central hypothesis is that recognition of DNA by cGAS sustains the inflammatory macrophages via activation of the type I interferon (IFN) pathway that promotes inflammasone activation; as a result, cGAS is crucial in ischemia-induced remodeling. This hypothesis has been formulated on the preliminary data and the recently published work from my laboratory. The rationale is that understanding the intracellular danger recognition in ischemic-triggered inflammation has the potential to discover effective ways of limiting inflammation-related injury. Guided by strong preliminary data, this hypothesis will be tested by pursuing the following specific aims: 1) Determine whether cGAS activation in macrophages drives ischemia- induced remodeling and define the source of the cytosolic DNA; 2) Determine whether cGAS sustains inflammation in macrophages by promoting AIM2 and NLRP3 inflammasome and caspase 11-mediated pyroptosis; 3) Identify effective and clinically relevant approaches for inhibition of cGAS. Aim 1 will be addressed using a cGASf/f mouse line to determine macrophage as the responsible cell type. Studies are also designed to trace the source of the cytosolic DNA. Under the second aim, I will determine if guanylate-binding proteins (GBP), induced by cGAS activation, increase danger signal visibility to sensors like AIM2 and NLRP3 and if cGAS-depndent priming is essential in cGAS-triggered inflammasome activation in ischemia. Pyroptosis- mediated by caspase 11 will also be evaluated. Aim 3 will identify clinically relevant strategies to inhibit cGAS by assessing two agents that treat inflammatory disorders. The study is conceptually novel by targeting DNA and its receptor cGAS, a bona fide anti-viral response, in the setting of myocardial ischemia. Knowledge acquired will vertically advance our understanding of the critical role of intracellular immunity in ischemic injury. As ischemic heart disease is an enormous burden and often a devastating condition, the proposed study moves the field forward by finding novel strategies alleviating the burden and improve care. Additionally, results will help to understand potential cardiac side effects from immunotherapy via boosting cGAS-STING pathway activity (in clinical trials).