Macrophages as effectors of cell therapy for heart failure

项目摘要/摘要 减少梗塞面积(IS)的新方法在翻译中停滞不前。鉴于急性胰腺炎的临床治疗 心肌梗死(AMI)主要表现为急于打开梗塞相关动脉，辅助治疗 再灌注后工作是非常可取的。在这里，我建议研究细胞的机制 后处理：再灌注20分钟后给予细胞治疗可减少致命性损伤的程度，改善 功能恢复，减缓向心力衰竭(HF)的进展。该时序与 标准的临床实践是，如果动脉被打开，治疗的决定可以推迟到动脉开放之后 有有效的现成产品可供选择。同种异体心脏球源性细胞(CDCs)可用于 立即使用，正在进行慢性心肌梗死的第二阶段临床测试。来自大鼠的初步数据显示，疾控中心，以及 其分泌的外切体(CDCexo)，如果在急性心肌梗死再流后给予合理的延迟，是具有心脏保护作用的。 我检查了48小时和2周的终点，分别关注心脏保护的急性和慢性益处。 为了确定最佳治疗模式，我系统地改变了再灌注和再灌注之间的时间间隔 CDC或CDCexo的交付。在45分钟的缺血发作后20分钟，我看到IS最大的下降， 对心脏功能的改善效果最好。在已发表的研究中，我发现巨噬细胞(Mϕ)是必不可少的 细胞后处理的效应器；它们的耗尽破坏了细胞后处理。相反，领养 转移CDC或CDCexo诱导的M-ϕ具有心脏保护作用。这里的主要机械论目标是理解 外切体介导的M-ϕ变化如何导致急性心肌保护(MI后数天)和长期保护 抗心力衰竭(心肌梗塞后数周)。具体地说，我将测试CDCexo-primed Mϕ展示增强的概念 胞吐作用(清除有毒细胞碎片的能力)，从而提高恢复和预防 向高频方向发展。这里的重点是心脏保护(防止心肌细胞死亡)，而不是 再生，以及CDC和CDCexo介导的增强泡腾作用的机制。老鼠将被用来 我们所有的机械学研究。泡泡吞噬的作用将通过两种新的体外共培养试验来探讨 巨噬细胞、中性粒细胞和应激心肌细胞，以及转基因小鼠的体内实验 用MI来量化和确定CDCexo介导的泡腾作用的机制。这项工作有潜力 阐明细胞疗法防止进展为心衰的心肌保护机制。

PROJECT SUMMARY/ABSTRACT Novel approaches to reduce infarct size (IS) have stalled in translation. Given that clinical treatment of acute myocardial infarction (AMI) is dominated by a rush to open the infarct-related artery, adjunctive therapies which work after reperfusion are highly desirable. Here I propose to investigate the mechanism of cellular postconditioning: cell therapy delivered 20 mins post-reperfusion can reduce the extent of lethal injury, improve functional recovery, and attenuate the progression toward heart failure (HF). The timing is compatible with standard clinical practice in that the decision to treat can be delayed until after the artery has been opened, if an efficacious off-the-shelf product is available. Allogeneic cardiosphere-derived cells (CDCs) are available for immediate use and are in phase 2 clinical testing for chronic MI. Preliminary data from rats show that CDCs, and their secreted exosomes (CDCexo), are cardioprotective when given with a reasonable delay after reflow in AMI. I examined 48 hr and 2 wk endpoints to focus on the acute and chronic benefits of cardioprotection, respectively. To determine the optimal treatment paradigm, I varied systematically the interval between reperfusion and delivery of CDCs or CDCexo. Twenty mins after a 45-min ischemic episode, I saw the greatest decreases of IS, and the best improvements in cardiac function. In published work, I found that macrophages (Mϕ) are essential effectors of cellular postconditioning; their depletion abrogates cellular postconditioning. Conversely, adoptive transfer of CDC- or CDCexo-primed Mϕ is cardioprotective. The major mechanistic objective here is to understand how exosome-mediated changes in Mϕ lead to acute cardioprotection (days after MI) and long-term protection against HF (weeks after MI). Specifically, I will test the concept that CDCexo-primed Mϕ exhibit enhanced efferocytosis (the ability to scavenge toxic cellular debris), thereby improving recovery and preventing progression toward HF. The focus here is on cardioprotection (prevention of cardiomyocyte death), rather than regeneration, and the mechanism of CDC- and CDCexo-mediated enhanced efferocytosis. Mice will be used for all our mechanistic studies. The role of efferocytosis will be probed both by novel in vitro co-culture assays of macrophages, neutrophils, and stressed cardiomyocytes, as well as by in vivo experiments in transgenic mice with MI to quantify and determine the mechanism of CDCexo-mediated efferocytosis. This work has the potential to elucidate the cardioprotective mechanisms of cell therapy that prevent progression to HF.