Preclinical studies of pluripotent stem cell-derived myogenic progenitors in non-human primates

总结 肌营养不良是遗传和临床异质性疾病，其特征在于进行性肌营养不良。 控制运动的骨骼肌的虚弱和退化。最常见的是杜兴 肌营养不良症（DMD）是由肌营养不良蛋白糖蛋白的遗传和生化缺陷引起的 复合物（DGC）。这些改变导致细胞膜损伤和肌肉细胞死亡，导致慢性 组织变性和肌肉收缩力受损。虽然目前没有有效的治疗方法， 一种有吸引力的治疗方法是使用基于细胞的疗法来促进肌肉再生。一直 诱导多能干细胞（iPS）在治疗癌症方面的治疗潜力令人兴奋。 遗传性疾病，因为这些细胞具有几乎无限的增殖潜力，并且可以分化成所有细胞， 类型我们开创了一种从多能干细胞中产生可移植骨骼肌祖细胞的方法， 细胞通过条件表达Pax3或Pax7。这种方法导致高效地生成 治疗性肌源性祖细胞，当移植到营养不良小鼠时，其局部或全身产生 大量的功能性骨骼肌组织，通常与宿主肌肉结合。重要的是， 一部分移植细胞保持单核，并显示骨骼肌干细胞的关键特征， 包括卫星细胞定位，对再损伤的反应，以及对继发性肌肉再生的贡献。 移植试验基于这些令人鼓舞的发现，我们已经开始制造这些细胞 在cGMP相容的条件下进行，并在鼠受体中进行临床前研究。结果从这些 研究是有希望的，但在将这种疗法推向临床转化之前， 可扩展性、递送、分布、安全性和在较大动物模型中的植入。因此，我们建议 使用非人灵长类动物（NHP）作为受体进行临床前研究以研究这些参数。还将 对于理解HLA错配对肌肉植入的影响至关重要，NHP代表了理想的系统 来正确地解决这个问题。NHP iPS细胞来源的肌源性祖细胞在NHP中的移植 接受者将为理解同种异体环境中的耐受性提供关键知识。这方面， 对再生医学有重要意义，但在多能干细胞中却被忽视了。 领域这些都是将这种疗法推向成功临床转化的关键先决条件。

Summary Muscular dystrophies are genetically and clinically heterogeneous disorders characterized by progressive weakness and degeneration of the skeletal muscles that control movement. The most common, Duchenne Muscular Dystrophy (DMD), is caused by genetic and biochemical defects of the dystrophin-glycoprotein complex (DGC). These alterations lead to cell membrane damage and death of muscle cells, resulting in chronic tissue degeneration and impaired muscle contractility. Although no effective treatment is available at present, one attractive therapeutic approach is to use cell-based therapies to promote muscle regeneration. There has been tremendous excitement for the therapeutic potential of induced pluripotent stem (iPS) cells in treating genetic diseases since these cells have virtually unlimited proliferation potential, and can differentiate into all cell types. We have pioneered a method to generate engraftable skeletal myogenic progenitors from pluripotent stem cells through conditional expression of Pax3 or Pax7. This approach results in highly efficient generation of therapeutic myogenic progenitors, which when transplanted into dystrophic mice locally or systemically produce large quantities of functional skeletal muscle tissue that incorporates normally into the host muscle. Importantly, a fraction of transplanted cells remains mononuclear, and displays key features of skeletal muscle stem cells, including satellite cell localization, response to re-injury, and contribution to muscle regeneration in secondary transplantation assays. Based on these encouraging findings, we have begun the manufacturing of these cells under cGMP compatible conditions and performed preclinical studies in murine recipients. The results from these studies are promising but before moving this therapy towards clinical translation, it would be ideal to assess scalability, delivery, distribution, safety, and engraftment in larger animal models. Therefore, here we propose preclinical studies to investigate these parameters using non-human primates (NHP) as recipients. It will also be critical to understand the impact of HLA mismatch on muscle engraftment, and NHP represent the ideal system to properly address this question. The transplantation of NHP iPS cell-derived myogenic progenitors into NHP recipients will provide critical knowledge for understanding tolerance in the allogeneic setting. This aspect, which has important implications for regenerative medicine, has been mostly overlooked in the pluripotent stem cell field. These are all critical prerequisites to advance this therapy towards successful clinical translation.