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

描述（由申请人提供）：脊髓性肌萎缩症（SMA）是婴儿死亡的主要遗传原因，发生率为1：6，000至1：10，000活产。SMA是由运动神经元存活基因1（SMN）的纯合缺失引起的，导致脊髓中α-运动神经元的进行性缺失，导致躯干和四肢肌肉萎缩。干细胞用于治疗神经系统疾病的治疗用途取决于产生特定细胞类型的能力。虽然人类有SMN的第二个拷贝（SMN 2），但该基因含有一个非多态性的C到T转换，产生一种不稳定的截短蛋白，缺乏SMN 1基因产生的全长蛋白的功能。目前用于SMA研究的实验模型依赖于人类细胞系或SMA患者成纤维细胞，这两种细胞系或成纤维细胞都不会使运动神经元群体受到特别影响，或者来自携带SMN 1突变的转基因小鼠的啮齿动物运动神经元。然而，小鼠没有SMN 2，因此疾病过程或机制可能与人类疾病无关。人类胚胎干细胞可以被指导产生感兴趣的特定细胞类型，但对它们的使用的伦理反对以及产生SMN 1突变的必要遗传操作限制了它们的有用性。随着新的干细胞技术的出现，从成人皮肤产生诱导多能干细胞（iPS）开辟了研究神经退行性疾病的新途径，因为有可能产生患者特异性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产生了iPS细胞，在这个探索性的研究计划中，我们的目标是从这些细胞中开发神经元（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，在此平台上可以进行广泛的实验，包括了解疾病机制，神经元脆弱性和治疗药物筛选，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.