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。对小鼠的遗传学研究表明，大多数心肌细胞 再灌注心肌梗死 (MI/R) 期间的死亡是通过调节的细胞死亡程序发生的。这表明应该是 从概念上讲，限制 MI/R 期间心肌细胞死亡是可能的，以获得再灌注维持维持的全部益处 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 由几个受调节的细胞凋亡和坏死程序介导，以及连接这些程序的机制 产生整合的细胞死亡反应的机制仍知之甚少。这种知识上的差距一直是 合理设计限制 MI/R 期间心脏损伤的疗法的关键障碍。据此，一个目标 我们实验室的目标是了解连接 MI/R 细胞死亡程序的分子框架。我们的 初步研究已确定 caspase-9 是细胞凋亡和坏死程序之间的重要联系 MI/R 期间。 caspase-9 在细胞凋亡中的典型作用是激活下游 procaspases-3 和 -7。 然而，我们发现了 caspase-9 在 MI/R 期间介导心肌细胞坏死的新途径。 与 caspase-9 介导的细胞凋亡相反，caspase-3/7 对于 caspase-9 介导的坏死是可有可无的 表明两条路径的区别。然而，与细胞凋亡一样，Caspase-9 酶活性 必需的。为了进一步剖析该途径，我们对 procaspase-9 相互作用进行了基于蛋白质组学的筛选 MI/R 期间心脏中的蛋白质，揭示了已知参与坏死各个方面的蛋白质。 到目前为止，我们重点关注了一种 procaspase-9 相互作用蛋白 SERCA2a，我们假设其功能 caspase-9 下游介导细胞内在杀伤。我们的数据表明 caspase-9 裂解 SERCA2a 在 MI/R 期间禁用其功能，这与之前的遗传学研究一致，表明 SERCA2a 缺失会加剧 心肌细胞坏死和梗塞面积。然而，我们相信 procaspase-9 和 SERCA2a 更为复杂。除了 caspase-9 诱导 SERC2a 丢失外，我们的数据表明 SERCA2a 损失可能通过 Ca2+ 过载导致 caspase-9 激活。因此，我们假设双向 caspase-9 和 SERCA2a 之间存在相辅相成的关系，有助于心肌细胞 MI/R 中坏死和梗塞的产生。该项目研究 caspase-9 介导的关键方面 坏死途径，包括激活机制、下游信号传导、途径与细胞的关系 被认为与 MI/R 相关的死亡程序，以及是否可以通过治疗抑制该途径来限制 梗塞面积。目标 1. 对体内 MI/R 过程中的 caspase-9 坏死轴进行遗传学剖析。目标 2. 描绘 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. 至 评估使用细胞渗透性肽在 MI/R 期间特异性抑制 procaspase-9 的治疗效果 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 中显得很重要，并且可能为限制梗塞面积的新治疗方法提供基础。