Biomimetic Coacervate Delivery of Muscle Stem Cell to Improve Cardiac Repair

描述（由申请人提供）：细胞心肌成形术（CCM）涉及将外源性细胞移植到心脏中，是修复受损心肌和改善心脏功能的有前景的方法。我们已经从小鼠和人的骨骼肌中分离出了一群肌源性干细胞（MDSC），与成肌细胞相比，它们在急性心肌梗死（AMI）小鼠模型中显示出显著改善的心脏再生能力。移植的MDSC存活显著优于骨骼肌成肌细胞，这是由于它们的细胞抗氧化剂的高表达，这赋予细胞增加的抗应激性，并且通过旁分泌效应减少心肌纤维化，促进血管生成，并改善左心室（LV）重塑。我们已经成功地将人MDSC扩增至培养物中的临床相关数量，更重要的是，人MDSC已经进入治疗膀胱功能障碍和心肌梗死的临床竞技场，证实了MDSC代表CCM的可行治疗性细胞来源。然而，存在一些限制，例如细胞的差的递送方法（在PBS中直接心肌内注射），其也导致有限的细胞保留和存活 由于MDSC的低心肌发生潜力，仍然可能限制MDSC的心脏再生潜力（本申请的主要焦点）。使用FGF 2-凝聚层作为MDSC的新型递送载体，代表了一个新的研究领域，不仅可以促进MDSC的细胞保留、存活和心脏再生潜力，而且还可以通过释放FGF 2协同增强血管生成。我们已经表明，载有FGF 2的凝聚物能够通过促进血管生成和支持残余心肌细胞的存活来增强心脏修复和再生（初步数据）。因此，本提案的目标1的重点将是将新的FGF 2-凝聚技术与MDSC联合收割机结合，以进一步改善心脏修复。我们将分别将这种组合疗法与MDSC和FGF 2凝聚物疗法进行比较。此外，我们已经观察到，用Wnt- 11（心脏发生所需的分子）病毒转导MDSC，当直接注射到损伤的心肌中时，增强了MDSC在体外的心肌分化和在体内的心脏修复。在第二组实验（目的2）中，我们将确定与FGF 2凝聚物组合的Wnt-11转导的MDSC（Wnt-11 MDSC）的心肌内注射是否可以在与用FGF 2凝聚物递送的未转导的MDSC和诱导性多能干细胞（iPSC）衍生的心肌细胞相比时进一步增强Wnt-11 MDSC的心脏再生潜力。这些目标的成功完成将增加我们对肌源性祖细胞群体的基本生物学的理解，其具有增强的心肌修复潜力，并促进新治疗技术的开发，该技术将干细胞治疗的优点与仿生凝聚物相结合，以改善心脏修复和再生。

DESCRIPTION (provided by applicant): Cellular cardiomyoplasty (CCM), which involves the transplantation of exogenous cells into the heart, is a promising approach to repair injured myocardium and improve cardiac function. We have isolated a population of muscle-derived stem cells (MDSCs) from the skeletal muscle of mice and humans, that when compared with myoblasts, display a significantly improved capacity for cardiac regeneration in a mouse model of acute myocardial infarction (AMI). Transplanted MDSCs survive significantly better than skeletal myoblasts due to their high expression of cellular antioxidants, which confers the cells with an increased resistance to stress, and through a paracrine effect which reduces myocardial fibrosis, promotes angiogenesis, and ameliorates left ventricular (LV) remodeling. We have successfully expanded human MDSCs, to clinically relevant numbers in culture and more importantly, human MDSCs have already entered the clinical arena for the treatment of bladder dysfunction & myocardial infarction, confirming that MDSCs represent a viable therapeutic cell source for CCM. However, several limitations, such as a poor delivery approach of the cells (direct intramyocardial injection in PBS) that leads to limited cell retention and survival as well as the low cardiomyogenic potential of the MDSCs, may still limit the cardiac regenerative potential of the MDSCs (Primary focus of the application). The use of FGF2-coacervate, as a novel delivery vehicle for the MDSCs, represents a new area of research that could not only promote cell retention, survival, and the cardiac regenerative potential of the MDSCs, but also synergistically enhance angiogenesis through the release of FGF2. We have shown that coacervate loaded with FGF2 was capable of enhancing cardiac repair and regeneration through the promotion of angiogenesis and supporting the survival of residual cardiomyocytes (preliminary data). Therefore, the focus of Aim 1 of this proposal will be to combine the new FGF2-coacervate technology with MDSCs to further improve cardiac repair. We will compare this combinatorial therapy to MDSCs and FGF2- coacervate therapies separately. Moreover, we have observed that the viral transduction of MDSCs with Wnt- 11, a molecule required for cardiogenesis, enhances the cardiomyogenic differentiation of the MDSCs in vitro and cardiac repair in vivo when injected directly into injured myocardium. In a second set of experiments (Aim 2), we will determine whether the intramyocardial injection of Wnt-11 transduced MDSCs (Wnt-11 MDSCs) in combination with FGF2 coacervate, can further enhance the cardiac regenerative potential of the Wnt-11 MDSCs when compared to non-transduced MDSCs and Inducible Pluripotent Stem Cell (iPSC)- derived cardiomyocytes delivered with FGF2-coacervate. The successful completion of these aims will increase our understanding of the basic biology of muscle-derived progenitor cell populations with enhanced cardiomyogenic potential for cardiac repair and facilitate the development of new therapeutic technologies that merge the merits of stem cell therapy with biomimetic coacervate to improve cardiac repair and regeneration.