Biomimetic Coacervate Delivery of Muscle Stem Cell to Improve Cardiac Repair

描述(申请人提供)：细胞性心肌成形术(CCM)涉及到将外源细胞移植到心脏内，是修复受损心肌和改善心功能的一种很有前途的方法。我们从小鼠和人的骨骼肌中分离出一组肌源性干细胞(MDSCs)，与成肌细胞相比，在急性心肌梗死(AMI)小鼠模型中，MDSCs的心脏再生能力显著提高。移植的MDSCs的存活明显好于骨骼肌母细胞，这是因为它们高表达细胞抗氧化剂，使细胞对应激的抵抗力增强，并通过旁分泌效应减少心肌纤维化，促进血管生成，改善左心室(LV)重塑。我们已经成功地将人MDSCs扩增到临床相关的培养数量，更重要的是，人MDSCs已经进入临床领域，用于治疗膀胱功能障碍和心肌梗死，证实MDSCs是CCM的一种可行的治疗细胞来源。然而，一些局限性，例如细胞的糟糕输送方法(在PBS中直接心肌内注射)导致细胞保留和存活也有限 由于MDSCs的心肌再生潜力较低，仍可能限制MDSCs的心脏再生潜力(应用的主要焦点)。FGF2凝聚体作为MDSCs的一种新型载体，代表了一个新的研究领域，不仅可以促进MDSCs的细胞保持、存活和心脏再生潜力，而且还可以通过释放FGF2协同促进血管生成。我们已经证明，携带FGF2的凝聚酸能够通过促进血管生成和支持残留心肌细胞的存活来促进心脏修复和再生(初步数据)。因此，这项提案的目标1的重点将是将新的FGF2凝聚技术与MDSCs相结合，以进一步改善心脏修复。我们将把这种联合疗法分别与MDSCs和FGF2凝聚疗法进行比较。此外，我们还观察到，将心脏发生所需的分子WNT-11病毒转导MDSCs，可促进MDSCs在体外的心肌分化和体内心脏修复，当直接注射到受损心肌中时。在第二组实验(目标2)中，我们将确定心肌内注射WNT-11转导的MDSCs(WNT-11 MDSCs)与FGF2凝集物联合使用是否可以进一步增强WNT-11 MDSCs的心脏再生潜力，与未转导的MDSCs和携带FGF2凝集物的可诱导多能干细胞(IPSC)来源的心肌细胞相比。这些目标的成功实现将增加我们对肌源性祖细胞群体的基本生物学的了解，这些细胞群体具有增强的心肌修复潜力，并有助于开发新的治疗技术，将干细胞治疗的优点与仿生凝聚相结合，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.