Harnessing Paracrine Mechanisms of Stem Cell-mediated Cardiac Contractile Enhancement

一种治疗非缺血性心肌病(NICM)心力衰竭的新方法 涉及骨髓间充质干细胞(MSCs)的输送，可以改善CM在细胞培养中的表现 在动物模型中，并正在进行临床试验。骨髓间充质干细胞疗法的功能益处 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 直接细胞-细胞相互作用，或通过间接旁分泌信号，通过可溶性因子或通过特殊的 被称为外体的微囊可以转移分子货物。了解MSC增强的CM功能 可能导致心脏疗法的改进，但现有模型的局限性阻碍了进展 了解心脏壁龛环境中旁分泌信号的系统。 直接解决NHLBI的一个特别感兴趣的主题(HL-142)，即外体作为旁分泌信号的作用 心血管疾病的介体，这项提议旨在使用3D人类工程心脏组织(Hect)作为 一种可控的人心肌体外仿生模型及其主要影响因素 间充质干细胞对心肌细胞收缩功能的潜在影响。一种新型多体式生物反应器 具有集成力传感技术的系统产生了初步数据，支持主要 外源性旁分泌信号机制的作用，包括生物活性分泌外体，显著 在人类工程心脏组织中，骨髓间充质干细胞和细胞间充质干细胞之间的直接偶联的好处。 主导假说是MSC治疗导致心肌细胞收缩的直接增强 主要通过旁分泌信号机制发挥作用，这些信号机制涉及可以识别的分泌外体， 分离、解构并作为治疗非缺血性心力衰竭的替代疗法。具体目标1 将解决最大限度地提高Hect收缩的MSC旁分泌的环境条件 性能，促进我们对调节心脏活动信号的特定生物物理刺激的理解 流程。目标2将确定外切体及其分子货物在MSC介导的收缩中的作用 通过评估hMSC外切体和Cargo对Hect收缩功能的效力增强hECTs (次级目标2a)和确定hMSC外切体货物中铅变力化合物的分子同一性 (次级目标2b)。最后，目标3将评估交付的hMSC外切小体来源的治疗效果。 用体外(亚靶3a)和在体(亚靶3b)模型研究心脏变力因子对心脏收缩功能恢复的影响 非缺血性心力衰竭。通过捕捉MSC治疗的好处，同时规避潜在的风险 活细胞移植，这一建议可能会改善心力衰竭患者的治疗选择 死于非缺血性心肌病。

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.