Danger Signaling and Spread of Injury after Myocardial Infarction

 描述（由申请人提供）：心肌梗死（MI）是美国的主要死亡原因。那些存活下来的，经常继续发展心室功能障碍和心力衰竭。虽然血运重建显著降低了心肌梗死后的死亡率， 开发防止心肌细胞死亡的MI后心脏保护疗法一直不成功。在这里，我们考虑一种替代的治疗方法，限制过度和适应不良的先天免疫反应细胞死亡。当细胞死亡时，它们会释放危险信号，这些信号与我们的免疫系统识别病原体的分子特征重叠。因此，MI激发了强烈的先天免疫应答。我们发现，IRF 3，抗病毒反应的主调节器在MI的发病机制中起着意想不到的重要作用。与野生型小鼠相比，IRF 3缺陷的小鼠表现出显著更少的炎症，并且在MI后显著免于死亡。我们推测梗死边缘区的心肌细胞和心脏驻留巨噬细胞在传播IRF 3依赖性信号、促进免疫性梗死扩展以及增加MI后心力衰竭和死亡的风险方面发挥独特作用。本K99/R 00的科学目的是：1）确定哪种危险信号通路负责MI后IRF 3的激活，2）确定哪种心脏细胞类型负责MI后IRF 3介导的损伤和死亡，3）开发IRF 3激活的药理学抑制剂作为一类新型MI后心脏保护剂。这些研究的长期目标是确定心肌梗死后可以使用的心脏保护剂，以限制“免疫性梗死扩展”和慢性心力衰竭的发展。申请人是一名接受过工程学、先天免疫学和临床心脏病学培训的医生兼科学家。该补助金将通过1）高级免疫学，分子成像，生物统计学，负责任的研究行为和实验室管理的结构化培训促进他向调查独立性的过渡;和2）由临床心脏病学，心脏免疫学，先天免疫，分子成像，治疗开发和药物输送专家组成的多学科导师和顾问团队的指导。

 DESCRIPTION (provided by applicant): Myocardial infarction (MI) is the leading cause of death in the US. Those that survive, frequently go on to develop ventricular dysfunction and heart failure. While revascularization has dramatically reduced mortality after MI, ongoing efforts to develop post-MI cardioprotective therapies that prevent cardiomyocyte cell death have been unsuccessful. Here, we consider an alternative therapeutic approach, limiting the excessive and maladaptive innate immune response to cell death. When cells die, they release danger signals that overlap with the molecular features used by our immune system to recognize pathogens. As a result, MI elicits strong innate immune responses. We found that IRF3, a master regulator of the antiviral response plays an unexpected essential role in the pathogenesis of MI. Mice deficient in IRF3 exhibited significantly less inflammation and were strikingly protected from death after MI compared to wild type mice. We hypothesize that cardiomyocytes and cardiac resident macrophage in the infarct borderzone play unique roles in spreading IRF3-dependent signals, promoting immunologic infarct expansion, and increasing the risk of heart failure and death after MI. The scientific aims of this K99/R00 are to 1) identify which danger signaling pathway is responsible for activation of IRF3 after MI, 2) identify which cardiac cell type(s) are responsible for IRF3- mediated injury and death after MI, and 3) to develop pharmacologic inhibitors of IRF3 activation as a novel class of post-MI cardioprotectants. The long-term goal of these studies is to identify cardioprotectants that can be administered post-MI to limit "immunologic infarct expansion" and development of chronic heart failure. The applicant is a physician-scientist trained in engineering, innate immunity, and clinical cardiology. This grant will facilitate his transition to investigative independence through 1) structured training in advanced immunology, molecular imaging, biostatistics, responsible conduct of research, and laboratory management; and 2) guidance from a multidisciplinary team of mentors and advisors comprised of experts in clinical cardiology, cardiac immunology, innate immunity, molecular imaging, therapeutics development, and drug delivery.