Inflammasome-Mediated Cardiac Cell Death in the Aged Female Rat Heart

项目摘要 急性心肌梗死（AMI）是绝经后妇女死亡的主要原因，但年龄- 相关的雌激素损失影响心脏缺血-再灌注（I/R）损伤的交叉点，NLRP 3 炎性体信号传导和随后的AMI发病机制尚未测试。可行性数据表明， NLRP 3炎性小体过度活化和心脏线粒体质量控制失调可能会产生毒性 前馈回路加剧了老年女性的促炎反应和AMI进展。年龄- 相关的慢性炎症可通过受损的巨噬细胞极化放大氧化应激。我们 将确定和表征促进焦亡的NLRP 3免疫信号传导中的关键年龄相关变化， 和梗死进展，并确定心脏线粒体自噬不足是否是NLRP 3的驱动因素 老年女性I/R损伤后炎性小体过度活化（目的1）。我们接下来将确定是否急性 使用小分子抑制剂的NLRP 3炎性体抑制，有和没有巨噬细胞耗竭， 通过涉及修复性M2巨噬细胞表型表达的机制赋予心脏保护作用， 保护性心肌线粒体质量控制（Aim 2）。我们认为靶向的NLRP 3炎性小体 抑制将通过独特和重叠的机制拯救绝经后的老年心脏， 心脏巨噬细胞极化、线粒体自噬和限制性脑源性危险相关分子 模式（DAMP）。拟议的研究是我们实验室正在进行的工作的逻辑延伸， 明确年龄相关性雌激素丢失对心脏I/R损伤的影响。F344雌性大鼠将 在15个月时切除卵巢，年龄到24个月，以更好地模拟人类更年期，NLRP 3敲除大鼠作为证据 的概念，成年和老年雄性大鼠进行临床比较。冠状动脉结扎将用于诱导 AMI与可变再灌注超过7天，以测试我们的心脏免疫细胞亚群的具体目标， 线粒体这项研究的发现对于确定NLRP 3炎性小体的作用将是非常宝贵的。 在老年女性心脏I/R损伤的介导的调节，并强烈支持NLRP 3炎性体作为一种免疫调节因子。 减少绝经后老年妇女AMI的治疗目标。我们将首次确定 NLRP 3炎性小体过度活化对老年人AMI易感性的影响及其机制 雌性（和雄性）大鼠。

Project Summary Acute myocardial infarction (AMI) is the leading cause of death in post-menopausal women, but how age- associated estrogen loss impacts the intersection of cardiac ischemic-reperfusion (I/R) injury, NLRP3 inflammasome signaling and subsequent AMI pathogenesis is untested. Promising feasibility data suggest that NLRP3 inflammasome hyperactivation and dysregulated cardiac mitochondrial quality control may create a toxic feed forward circuit to exacerbate proinflammatory responses and AMI progression in aged females. Age- associated chronic inflammation may amplify oxidative stress through impaired macrophage polarization. We will identify and characterize key age-associated changes in NLRP3 immune signaling that promote pyroptosis and infarct progression, and determine whether insufficient cardiac mitophagy is a driver of NLRP3 inflammasome hyperactivation following I/R injury in aged females (Aim 1). We will next determine if acute NLRP3 inflammasome suppression using a small molecule inhibitor, with and without macrophage depletion, confers cardioprotection through a mechanism involving reparative M2 macrophage phenotypic expression and protective cardiac mitochondrial quality control (Aim 2). We propose that targeted NLRP3 inflammasome inhibition will rescue the post-menopausal aged heart through unique and overlapping mechanisms involving cardiac macrophage polarization, mitophagy, and limiting mitochondrial-derived danger associated molecular patterns (DAMPs). The proposed studies are a logical extension of ongoing work in our laboratory, which seeks to define the effects of age-associated estrogen loss on cardiac I/R injury. F344 female rats will be ovariectomized at 15 mo and aged to 24 mo to better mimic human menopause, NLRP3 knock out rats for proof of concept, and adult and aged male rats for clinical comparison. Coronary artery ligation will be used to induce AMI with variable reperfusion over 7 days to test our specific aims in cardiac immune cell subsets and mitochondria. The findings from this study will be invaluable in establishing a role for NLRP3 inflammasome- mediated regulation of I/R injury in the aged female heart and strongly support the NLRP3 inflammasome as a therapeutic target for AMI reduction in older post-menopausal women. We will determine, for the first time, the contribution and mechanism by which NLRP3 inflammasome hyperactivation impacts vulnerability to AMI in aged female (and male) rats.