Caspase-9 as a nodal point connecting necrotic and apoptotic cell death in myocardial infarction

Caspase-9 作为连接心肌梗死细胞坏死和凋亡的节点

• 批准号: 10504387
• 负责人: Richard N Kitsis
• 金额: $ 62.2万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-15 至 2026-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10504387
• 关键词: ATP2A2; Adult; Apoptosis; Apoptotic; Attenuated; CASP3 gene; CASP9 gene; Cardiac; Cardiac Myocytes; Cell Death; Cells; Cessation of life; Complex; Data; Drug Kinetics; Etiology; Event; Generations; Genetic study; Goals; Heart; Heart failure; Infarction; Inflammation; Knockout Mice; Knowledge; Link; Maps; Mediating; Molecular; Mus; Mutate; Myocardial Infarction; Necrosis; Nodal; Oxidative Stress; Pathway interactions; Peptides; Permeability; Proteins; Proteomics; Regulation; Reperfusion Therapy; Resistance; Role; SERCA2a; Series; Signal Transduction; Site; Stroke; Syndrome; Testing; Therapeutic; Tissues; apoptotic protease-activating factor 1; base; efficacy testing; heart damage; heart function; in vivo; inhibitor; mortality; mutant; novel; novel therapeutic intervention; novel therapeutics; programs; rational design; response; therapy design; x-linked inhibitor of apoptosis protein

The primary cardiac event in MI is cell death. Genetic studies in mice have established that most cardiomyocyte death during reperfused MI (MI/R) occurs through regulated cell death programs. This suggests that it should be possible in concept to limit cardiomyocyte death during MI/R to obtain the full benefit of reperfusion in maintaining cardiac function. A significant obstacle in achieving this goal, however, is that cardiomyocyte death in MI/R is mediated by several regulated apoptosis and necrosis programs, and the mechanisms that link these programs to produce an integrated cell death response remain poorly understood. This gap in knowledge has been a critical impediment for the rational design of therapies to limit cardiac damage during MI/R. Accordingly, a goal of our lab has been to understand the molecular framework that connects cell death programs in MI/R. Our preliminary studies have identified caspase-9 as an important link between apoptosis and necrosis programs during MI/R. The canonical role of caspase-9 in apoptosis is to activate downstream procaspases-3 and -7. However, we have identified a new pathway in which caspase-9 mediates cardiomyocyte necrosis during MI/R. In contrast to caspase-9-mediated apoptosis, caspases-3/7 are dispensable for caspase-9-mediated necrosis indicating the distinctness of the two pathways. However, as in apoptosis, caspase-9 enzymatic activity is required. To further dissect the pathway, we performed a proteomics-based screen for procaspase-9 interacting proteins in the heart during MI/R, which revealed proteins known to be involved in various aspects of necrosis. Thus far, we have focused on one procaspase-9 interactor, SERCA2a, which we hypothesize functions downstream of caspase-9 to mediate cell-intrinsic killing. Our data suggest that caspase-9 cleaves SERCA2a during MI/R disabling its function consistent with prior genetic studies showing that SERCA2a loss exacerbates cardiomyocyte necrosis and infarct size. We believe, however, that the relationship between procaspase-9 and SERCA2a is more complex. In addition to caspase-9 inducing SERC2a loss, our data suggest that SERCA2a loss may contribute to caspase-9 activation through Ca2+ overload. Thus, we hypothesize that a bidirectional mutually-reinforcing relationship exists between caspase-9 and SERCA2a and contributes to cardiomyocyte necrosis and infarct generation in MI/R. This project investigates critical aspects of the caspase-9-mediated necrosis pathway including activation mechanisms, downstream signaling, the relationship of the pathway to cell death programs thought to be involved in MI/R, and whether this pathway can be therapeutically inhibited to limit infarct size. Aim 1. To genetically dissect the caspase-9 necrosis axis during MI/R in vivo. Aim 2. To delineate the bidirectional regulation between caspase-9 and SERCA2A in cardiomyocyte necrosis during MI/R. Aim 3. To assess the therapeutic benefit of specifically inhibiting procaspase-9 during MI/R using a cell permeable peptide derived from an endogenous procaspase-9 inhibitor. These studies define a novel cell death pathway that appears important in MI/R and may provide the basis for a new therapeutic approach to limit infarct size.

MI中的主要心脏事件是细胞死亡。小鼠的遗传研究确定大多数心肌细胞 通过受监管的细胞死亡程序发生重新灌注MI（MI/R）期间的死亡。这表明应该是 在MI/R期间限制心肌细胞死亡的概念可能会获得再灌注的全部益处 心脏功能。然而，实现这一目标的一个重大障碍是MI/R中的心肌细胞死亡是 由几个受调节的细胞凋亡和坏死程序介导的，以及将这些程序联系起来的机制 产生综合的细胞死亡反应仍然很了解。知识的差距是 在MI/R期间限制疗法的合理设计的关键障碍。因此，一个目标 我们的实验室是要了解连接MI/R中细胞死亡程序的分子框架。我们的 初步研究已将caspase-9确定为凋亡与坏死程序之间的重要联系 在mi/r期间。 caspase-9在凋亡中的规范作用是激活下游procaspase-3和-7。 但是，我们已经确定了一种新途径，其中caspase-9在MI/R期间介导心肌细胞坏死。 与caspase-9介导的凋亡相反，caspase-3/7对于caspase-9介导的坏死是可分配的 指示这两种途径的独特性。但是，与凋亡一样，caspase-9酶活性是 必需的。为了进一步剖析途径，我们为procaspase-9进行了基于蛋白质组学的屏幕 MI/R期间心脏中的蛋白质，该蛋白显示出已知与坏死的各个方面有关的蛋白质。 到目前为止，我们专注于一个procaspase-9相互作用者SERCA2A，我们假设功能 caspase-9的下游介导细胞中性杀伤。我们的数据表明caspase-9裂解SERCA2A 在MI/R期间，与先前的遗传研究一致的功能一致，表明SERCA2A损失加剧了 心肌细胞坏死和梗塞大小。但是，我们相信procaspase-9和 SERCA2A更为复杂。除了caspase-9诱导SERC2A损失外，我们的数据表明SERCA2A 损失可能会导致CASPASE-9通过CA2+过载激活。因此，我们假设双向 caspase-9和serca2a之间存在互惠关系的关系，并有助于心肌细胞 MI/R中的坏死和梗死产生。该项目研究了caspase-9介导的关键方面 坏死途径，包括激活机制，下游信号，途径与细胞的关系 被认为涉及MI/R的死亡计划，以及是否可以在治疗上抑制该途径以限制 梗塞大小。目的1。在体内Mi/R期间遗传剖析caspase-9坏死轴。目标2。描述 MI/R期间心肌细胞坏死中caspase-9和SERCA2A之间的双向调节。目标3 评估使用可渗透肽在MI/R期间特别抑制procaspase-9的治疗益处 源自内源性procaspase-9抑制剂。这些研究定义了一种新的细胞死亡途径 在MI/R中似乎很重要，可以为一种新的治疗方法提供限制梗塞大小的基础。