Extraocular muscle stem cells for DMD therapy

杜兴氏肌营养不良症(DMD)是一种致命的疾病，由DMD基因突变引起，导致Dstrophin缺失或严重减少。目前的治疗方法不能显著减缓这种疾病，更不用说治愈了。我们的建议源于这样一个基本观察，即即使在晚期DMD病例中，EOMS在临床和病理上也是幸免的。这是一个耐人寻味的难题，因为我们之前已经证明，正常人的EOM会产生全长的dystrophin，而DMD患者的EOM中完全不存在dystrophin。这种现象会在不同物种间传播，因为犬类不会出现EOM。 (GRMD)和小鼠(MDX)DMD模型。尽管提出了许多假说并对其进行了检验，但对于EOM的保留并没有令人满意的解释。 三个关键发现提出了一个与EOM干细胞相关的新假说，以解释DMD中EOM的保留。首先，成人肌肉已被证明含有能够潜水、转分化和植入的干细胞。其次，表达谱和代谢标记实验表明，在成人EOM中看到的持续的肌肉生成可能与EOM中驻留的干细胞数量增加有关。第三，多药耐药表型已被证明通过肌肉抑制素阻断介导的促进肌肉生成/再生而得到改善。 我们建议对EOM干细胞有助于DMD中EOM的保留这一假设进行检验。我们 我将通过在一系列体外和体内实验中分析a)驻留在成人EOM中的干细胞的数量和b)与四肢肌肉中驻留的干细胞的植入和治疗潜力来验证这一假设。这些研究对于促进我们对DMD病理生理学的基本理解至关重要。此外，开展这项研究将为一种旨在利用成人EOM的肌源性MD干细胞潜力作为DMD治疗的可能手段的策略提供原则证明。

Duchenne's muscular dystrophy (DMD) is a fatal disorder caused by mutations in the DMD gene that results in an absence or severe reduction of dystrophin. Current therapies can not significantly slow down, let alone cure the disease. Our proposal stems from the basic observation that EOMs remain clinically and pathologically spared even in advanced cases of DMD. This presents an intriguing conundrum since we have previously shown that normal human EOM produce full-length dystrophin and that dystrophin is completely absent in the EOM of DMD patients. This phenomena extends across species as EOM are spared in the canine (GRMD) and murine (mdx) models of DMD. No satisfactory explanation for EOM sparing exists, despite many hypotheses having been proposed and tested. Three key findings suggest a novel hypothesis related to EOM stem cells to explain EOM sparing in DMD. First, adult muscle has been shown to contain stem cells that are capable of diving, transdifferentiation and engraftment. Second, expression profiling and metabolic labeling experiments suggest that the continual myogenesis seen in adult EOM may be related to increased numbers of stem cells resident in EOM. Third, the mdx phenotype has been shown to be ameliorated by myostatin blockade-mediated enhancement of myogenesis/regeneration. We propose to test the hypothesis that EOM stem cells contribute to sparing of EOM in DMD. We will test this hypothesis by analyzing a) the number and b) the engraftment and therapeutic potential of stem cells resident in adult EOM compared to limb muscle in a series of in vitro and in vivo experiments. The studies are critical for advancing our basic understanding of DMD pathophysiology. Additionally, undertaking this research would provide a proof-of-principle for a strategy designed to harness the myogenic md stem cell potential of adult EOM as a possible means of DMD-therapy.