Macrophages as effectors of cell therapy for heart failure

项目总结/摘要 减少梗死面积（IS）的新方法在翻译中停滞不前。鉴于急性的临床治疗 心肌梗死（AMI）主要是急于打开梗死相关动脉， 再灌注后的工作是非常需要的。在这里，我建议研究细胞的机制， 后处理：再灌注后20分钟给予细胞治疗可以降低致死性损伤的程度，改善细胞凋亡。 功能恢复，并减缓心力衰竭（HF）的进展。时间安排与 标准的临床实践是，如果患者的动脉被切开， 有效的现成产品是可用的。同种异体心球衍生细胞（CDC）可用于 立即使用，并处于慢性MI的2期临床试验中。大鼠的初步数据显示，CDC和 它们分泌的外泌体（CDCexo）在AMI再流后以合理的延迟给予时具有心脏保护作用。 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。 为了确定最佳的治疗模式，我系统地改变了再灌注和再灌注之间的间隔。 递送CDC或CDCexo。在45分钟的缺血发作后20分钟，我看到IS的最大下降， 以及心脏功能的最佳改善。在已发表的工作中，我发现巨噬细胞（M β）是必不可少的， 细胞后调节的效应物;它们的耗尽消除细胞后调节。相反，收养 CDC-或CDCexo-致敏的单核细胞的转移是心脏保护性的。这里主要的机械目标是理解 外泌体介导的M β变化如何导致急性心脏保护（MI后数天）和长期保护 抗HF（MI后数周）。具体来说，我将测试CDCexo引发的M细胞表现出增强的概念， 红细胞增多症（清除有毒细胞碎片的能力），从而改善恢复和预防 向HF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介导的增强的红细胞增多症的机制。小鼠将用于 我们所有的机械研究。将通过新的体外共培养试验， 巨噬细胞、中性粒细胞和应激心肌细胞，以及转基因小鼠体内实验 用MI定量和确定CDCexo介导的红细胞增多症的机制。这项工作有可能 阐明细胞治疗防止进展为HF的心脏保护机制。

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.