脊髓性肌萎缩症(SMA)是一种高度致死、致残的神经遗传病，其致病基因运动神经元生存基因（SMN）具有SMN1、SMN2两种拷贝，绝大多数SMA患者发生了SMN1基因缺失突变而SMN2基因正常，但SMN2在mRNA剪接过程中出现7号外显子跳跃，导致产生的全长蛋白不足而致病。提高全长SMN蛋白的表达是本病治疗的主要策略。虽然近年来本病在治疗研究方面取得了一定的进展，但存在给药方式困难、临床疗效不确切等问题，亟需探索新的治疗手段。我们前期建立了SMA患者来源的ips细胞系，定向分化获得了运动神经元，同时建立了Ⅰ型SMA小鼠模型。本项目将立足于良好的前期基础，设计特异性靶向SMN2转录调控区的sgRNA，应用dCas9系统募集VP64、p65、Rta等转录激活因子，分别在ips及SMA小鼠水平对SMN2基因进行激活，从SMN蛋白表达、运动神经元功能以及小鼠行为学等方面探讨其对SMA治疗的可行性。

Spinal muscular atrophy (SMA) is a frequently fatal neurogenic disorder caused by a genetic defect in the survival motor neuron (SMN) gene. In humans, SMN gene has 2 nearly identical forms, SMN1 and SMN2. Most cases of SMA result from homozygous deletions of the SMN1 gene. An alternative splicing event in the pre-mRNA arising from SMN2 results in the production of low levels of full-length SMN protein. Therefore, the main strategies to treat SMA focus on increasing the expression of full-length SMN. Recently, some progresses have been made in the treatment of SMA. However, some present limitations, such as the difficulty of administration routes and no clear consensus for their efficacy, raise demands for new therapeutic approaches. In our preliminary studies, we have established the cell line of SMA patient-specific induced pluripotent stem cells (iPSCs) and differentiated them into motor neurons. Moreover, we have also established the mouse model of Type I SMA. Base on the good basis of our preliminary studies, we plan to design sgRNAs targeting the transcriptional regulatory regions of SMN2. Subsequently, we will use CRISPR-dCas9 system to recruit transcription activator (VP64, p65, Rta and so on) binding the SMN2 region and further activate SMN2 in iPSCs and SMA models. We will evaluate the efficacy of this therapeutic strategy by testing the SMN protein expression, motor neuron function and mouse behavior.