Harnessing Paracrine Mechanisms of Stem Cell-mediated Cardiac Contractile Enhancement

一种治疗非缺血性心肌病（NICM）心力衰竭患者的新兴方法 包括间充质干细胞（MSC）的输送，可以改善细胞培养中的CM性能 和动物模型，并正在进行临床试验。MSC治疗的功能获益 可能涉及多种机制，但目前尚不清楚移植细胞是否主要通过 直接的细胞-细胞相互作用，或通过间接的旁分泌信号，通过可溶性因子或通过特殊的 一种叫做外泌体的微囊泡，可以转移分子货物。了解MSC增强的CM功能 可能导致心脏治疗的改进，但现有模型的局限性阻碍了进展 系统理解旁分泌信号在心脏生态位环境。 直接解决NHLBI特别感兴趣的主题（HL-142）外泌体作为旁分泌信号的作用 心血管疾病中的介质，该提案旨在使用3D人类工程心脏组织（hECT）作为 一个可控的仿生体外模型的天然人类心肌，以确定主要因素 潜在的MSC介导的对心肌细胞收缩功能的影响。一种新型的多人ECT生物反应器 一个集成了力传感技术的系统已经生成了初步数据，支持一种主要的 外源性旁分泌信号传导机制的作用，包括生物活性分泌的外泌体， 超过了在人类工程心脏组织中MSC和hCM之间直接偶联的益处。 主导假设是MSC治疗导致心肌细胞收缩性的直接增强， 主要通过涉及分泌的外泌体的旁分泌信号传导机制起作用， 分离、解构并作为非缺血性心力衰竭的替代疗法递送。具体目标1 将解决最大化MSC旁分泌增强hECT收缩的环境条件， 性能，推进我们对调节心脏活性信号的特定生物物理刺激的理解 流程.目的2将确定外泌体及其分子货物在MSC介导的收缩中的作用。 通过评估hMSC外来体和货物对hECT收缩功能的效力来增强hECT （子目的2a）和确定来自hMSC外来体货物的先导正性肌力化合物的分子身份 （次级目标2b）。最后，目标3将评估递送的hMSC外泌体衍生的重组人骨髓基质细胞的治疗功效。 使用体外（子目标3a）和体内（子目标3b）模型， 非缺血性心力衰竭通过获取MSC治疗的益处，同时规避潜在的风险， 活细胞移植，这一建议可能会导致改善心力衰竭患者的治疗选择， 非缺血性心肌病

An emerging approach to treat patients with heart failure from non-ischemic cardiomyopathy (NICM) involves delivery of mesenchymal stem cells (MSCs) that can that can improve CM performance in cell culture and in animal models, and are being tested in ongoing clinical trials. The functional benefits of MSC-therapy may involve a variety of mechanisms, but it remains unclear whether transplanted cells act primarily through direct cell-cell interactions, or through indirect paracrine signaling via soluble factors or via special microvesicles called exosomes that can transfer molecular cargo. Understanding MSC-enhanced CM function could lead to improved cardiotherapeutics, but progress has been hampered by the limits of existing models systems for understanding paracrine signaling in the cardiac niche environment. Directly addressing an NHLBI topic of special interest (HL-142) on the role of exosomes as paracrine signal mediators in cardiovascular disease, this proposal aims to use 3D human engineered cardiac tissue (hECT) as a controllable biomimetic in vitro model of native human myocardium in order to identify the primary factors underlying MSC-mediated effects on cardiomyocyte contractile function. A novel multi-hECT bioreactor system with integrated force-sensing technology has generated preliminary data supporting a predominant effect of extrinsic paracrine signaling mechanisms, including bioactive secreted exosomes, that significantly exceed the benefits of direct coupling between MSCs and hCMs in human engineered cardiac tissues. The governing hypothesis is that MSC treatment causes direct enhancement of cardiomyocyte contractile function primarily through paracrine signaling mechanisms involving secreted exosomes that can be identified, isolated, deconstructed and delivered as an alternative therapy for non-ischemic heart failure. Specific Aim 1 will resolve the environmental conditions that maximize MSC paracrine enhancement of hECT contractile performance, advancing our understanding of specific biophysical stimuli that modulate cardioactive signaling processes. Aim 2 will identify the role of exosomes and their molecular cargo in MSC-mediated contractile enhancement of hECTs by evaluating the potency of hMSC exosomes and cargo on hECT contractile function (Sub-aim 2a) and determining the molecular identity of lead inotropic compounds from hMSC exosome cargo (Sub-aim 2b). Finally, Aim 3 will evaluate the therapeutic efficacy of delivered hMSC exosome-derived cardiotropic factors on recovery of contractility using in vitro (Sub-aim 3a) and in vivo (Sub-aim 3b) models of non-ischemic heart failure. By capturing the benefits of MSC therapy while circumventing the potential risks of live cell implantation, this proposal may lead to improved treatment options for patients who suffer heart failure from non-ischemic cardiomyopathy.