Motor neuron generation from SMA patient-derived induced pluripotent stem cells

描述(申请人提供)：脊髓性肌萎缩症(SMA)是导致婴儿死亡的主要遗传原因，发生在1：6,000至1：10,000的活产儿中。SMA是由于存活运动神经元-1(SMN)基因纯合缺失，导致脊髓内α运动神经元进行性丧失，导致躯干和四肢肌肉萎缩所致。干细胞在治疗神经疾病方面的应用取决于产生特定细胞类型的能力。虽然人类有SMN(SMN)的第二个拷贝，但该基因包含一个非多态的C到T转换，它产生一种不稳定的截短蛋白，缺乏SMN1基因产生的全长蛋白的功能。目前用于研究SMA的实验模型依赖于人类细胞系或SMA患者成纤维细胞，这两种细胞都不会对运动神经元群体造成特别影响，或者是来自携带SMN1突变的转基因小鼠的啮齿动物运动神经元。然而，小鼠没有SMN2，因此疾病过程或机制可能与人类疾病没有那么相关。人类胚胎干细胞可以被指示产生特定的感兴趣的细胞类型，但对它们使用的伦理反对以及产生SMN1突变的必要基因操作限制了它们的有用性。随着新的干细胞技术的出现，成人皮肤诱导多能干细胞(IPS)的产生为研究神经退行性疾病开辟了新的途径，因为它有可能产生患者特有的iPS细胞系。我们已经从一个患有SMA的孩子和他的未受影响的母亲身上培养出iPS细胞，在这个探索性的研究方案中，我们的目标是从这些细胞培养神经元(特别是运动神经元)、星形胶质细胞和肌肉细胞。患者和/或疾病特异性iPS细胞的产生将是一个平台，可以在其上进行广泛的实验，包括了解疾病机制、神经元脆弱性和治疗性药物筛选，所有这些都与NIH改善公共健康的使命相关。

DESCRIPTION (provided by applicant): Spinal muscular atrophy (SMA) is the leading genetic cause of infantile death and occurs in 1:6,000 to 1:10,000 live births. SMA is caused by a homozygous loss of the survival motor neuron-1 (SMN) gene leading to the progressive loss of alpha-motor neurons in the spinal cord causing atrophy of trunk and limb muscles. The therapeutic use of stem cells for the treatment of neurological disorders depends on the ability to generate specific cell types. Although humans have a second copy of SMN (SMN2), this gene contains a non-polymorphic C to T transition that produces an unstable, truncated protein lacking the function of the full-length protein produced by the SMN1 gene. Current experimental models used for the study of SMA rely on human cell lines or SMA patient fibroblasts, neither of which make the motor neuron population particularly affected, or rodent motor neurons derived from transgenic mice carrying the SMN1 mutation. However, mice do not have SMN2 so the disease process or mechanisms might not be as relevant to the human disease. Human embryonic stem cells can be instructed to generate the specific cell types of interest, but ethical objections to their use as well as necessary genetic manipulations to generate the SMN1 mutation limit their usefulness. With the advent of new stem cell technologies, the generation of induced pluripotent stem (iPS) cells from adult skin has opened new avenues of studying neurodegenerative diseases because of the potential to generate a patient-specific iPS cell line. We have generated iPS cells from a child with SMA and his non-affected mother, and in this exploratory research proposal, we aim to develop neurons (specifically motor neurons), astrocytes, and muscle cells from these cells. The generation of patient and/or disease-specific iPS cells will be a platform upon which a wide range of experiments can be performed, including understanding disease mechanisms, neuronal vulnerability, and therapeutic drug screening, all of which are relevant to the NIH mission to improve public health.