Intra-arterial delivery of skeletal muscle stem cells

描述(由申请人提供)：这个探索性项目旨在评估系统地将供体周细胞移植到宿主骨骼肌的植入和成肌潜能。长期目标是开发基于细胞的治疗方法来对抗肌肉萎缩。寻找减少肌肉萎缩的方法在杜氏肌营养不良症中尤为突出，这是一种遗传性疾病，营养不良蛋白基因的突变会导致横纹肌的进行性萎缩和早期死亡。肌肉萎缩也与衰老有关，是许多疾病的标志，包括癌症、细菌败血症、艾滋病和糖尿病。肌肉萎缩会导致全身虚弱和虚弱，在极端情况下，当呼吸肌受累时，会导致窒息甚至死亡。建议的治疗肌肉萎缩障碍的方法之一是植入有助于肌纤维修复和增加肌肉质量的供体细胞。供体细胞需要被有效地输送到多个宿主肌肉，优先通过循环。然而，正在进行的研究表明，静脉内输送供体细胞是有问题的，因为许多细胞被困在肺(和其他过滤器官)中。因此，目前动脉内细胞注射似乎是高效输送供体细胞的有利手段。卫星细胞、真正的肌源性干细胞及其增殖的后代在系统输送时无法到达目标肌肉。最近的研究指出，血管周围细胞在肌营养不良症的细胞治疗中具有潜力。这些非典型肌源性来源的特征是基于它们在体外扩张后的特性。术语中血管母细胞(内皮相关CD31+细胞)和周细胞(吞噬内皮细胞的微血管相关收缩细胞)一直被交替使用，但其实际性质并未得到明确的解决。总之，肌源性细胞的微血管来源在基于细胞的肌肉治疗中的功能意义仍然是一个有争议的主题。为了以可重复的方式分析这一现象，需要开发标准化的方法来分离和表征这些非典型的肌源性细胞来源。这项应用的具体目的是：1.确定系统输送的供体周细胞是否可以靶向营养不良的肌肉并结合到肌纤维中。2.评估移植的供体细胞恢复肌肉完整性所必需的蛋白质表达的潜力。为了解决这些特定的目标，我们将首先使用dystrophin缺陷(MDX)宿主小鼠，并分析周细胞在肌膜中恢复dystrophin表达的有效性。供体周细胞将通过股动脉输送。拟议研究的预期结果将为肌肉营养不良和其他肌肉萎缩状况的基于细胞的治疗提供有价值的见解。 公共卫生相关性：肌肉萎缩与肌肉营养不良有关，会导致全身虚弱和虚弱，在严重的情况下，会导致早期死亡。肌肉萎缩也与衰老有关，是包括癌症和糖尿病在内的许多疾病的标志。这项拟议的研究将评估系统输送的供体细胞是否能够到达目标肌肉，并有助于肌肉修复和增加肌肉质量。预期的结果将为开发基于细胞的疗法来对抗肌肉萎缩疾病提供重要的见解。

DESCRIPTION (provided by applicant): This exploratory project aims to evaluate engraftment and myogenic potential of donor pericytes delivered systemically to host skeletal muscles. The long-term goal is the development of cell-based therapy for combating muscle wasting. The search for means to reduce muscle wasting has been especially intensified in Duchenne muscular dystrophy, a genetic disorder where mutations in the dystrophin gene lead to progressive waste of striated muscles and early lethality. Muscle wasting is also associated with aging and is a hallmark of a number of diseases, including cancer, bacterial sepsis, AIDS and diabetes. Muscle wasting can cause generalized weakness and debilitation and in its extreme, when respiratory muscles are involved, asphyxia and even death. One of the proposed ways to treat muscle wasting disorders is engraftment of donor cells that can contribute to myofiber repair and increase muscle mass. The donor cells would need to be delivered effectively to multiple host muscles, preferentially via circulation. However, ongoing studies have shown that intra-venous delivery of donor cells is problematic because many of the cells are trapped in the lungs (and other filter organs). Thus, at present, intra-arterial cell injection seems to be the favorable means for efficient delivery of donor cells. Satellite cells, bona fide myogenic stem cells and their proliferating progeny are unable to reach target muscles when delivered systemically. Recent studies have pointed to the potential of perivascular cells for cell-based therapy in muscular dystrophy. The characterization of these atypical myogenic sources has been based on their properties following ex vivo expansion. The terms mesoangioblasts (endothelium related CD31+ cells) and pericytes (microvasculature- associated contractile cells that engulf the endothelium) have been used interchangeably without a clear resolution of their actual nature. In all, the functional significance of microvasculature sources of myogenic cells in cell-based muscle therapy has remained a subject of debate. In order to analyze the phenomenon in a reproducible manner, standardized approaches need to be developed for isolating and characterizing these atypical sources of myogenic cells. The specific aims of this application are: 1. Determine whether systemically delivered donor pericytes can target dystrophic muscles and be incorporated into myofibers. 2. Evaluate the potential of the engrafted donor cells to restore expression of proteins essential for muscle integrity. To address these specific aims we will first use dystrophin deficient (mdx) host mice and analyze pericyte effectiveness in restoring dystrophin expression in the sarcolemma. Donor pericytes will be delivered via the femoral artery. The anticipated outcome of the proposed studies will provide valuable insights for cell-based therapies in muscular dystrophies and other muscle wasting conditions. PUBLIC HEALTH RELEVANCE: Muscle wasting is associated with muscular dystrophies and causes generalized weakness and debilitation and in severe cases, leads to early lethality. Muscle wasting is also associated with aging and is a hallmark of a number of diseases including cancer and diabetes. The proposed study will evaluate whether systemically delivered donor cells can reach target muscles and contribute to muscle repair and increased muscle mass. The anticipated results will provide important insights for developing cell-based therapies to combat muscle wasting disorders.