PDF(Pubmed)
Abstract：
GGGGCC (G4C2) repeat expansion in C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). How this genetic mutation leads to neurodegeneration remains largely unknown. Using CRISPR-Cas9 technology, we deleted EXOC2, which encodes an essential exocyst subunit, in induced pluripotent stem cells (iPSCs) derived from C9ORF72-ALS/FTD patients. These cells are viable owing to the presence of truncated EXOC2, suggesting that exocyst function is partially maintained. Several disease-relevant cellular phenotypes in C9ORF72 iPSC-derived motor neurons are rescued due to, surprisingly, the decreased levels of dipeptide repeat (DPR) proteins and expanded G4C2 repeats-containing RNA. The treatment of fully differentiated C9ORF72 neurons with EXOC2 antisense oligonucleotides also decreases expanded G4C2 repeats-containing RNA and partially rescued disease phenotypes. These results indicate that EXOC2 directly or indirectly regulates the level of G4C2 repeats-containing RNA, making it a potential therapeutic target in C9ORF72-ALS/FTD.
摘要：
GGGGCC（G4C2）在C9ORF72中重复扩增是肌萎缩侧索硬化症（ALS）和额颞叶痴呆（FTD）的最常见遗传原因。这种基因突变如何导致神经变性仍然是未知的。使用CRISPR-Cas9技术，我们删除了EXOC2，它编码一个必需的外囊亚基，来自C9ORF72-ALS/FTD患者的诱导多能干细胞（iPSC）。由于截短的EXOC2的存在,这些细胞是活的,表明外囊功能被部分维持。C9ORF72iPSC衍生的运动神经元中几种疾病相关的细胞表型被拯救，令人惊讶的是,降低二肽重复（DPR）蛋白的水平和扩大的含有G4C2重复的RNA。用EXOC2反义寡核苷酸处理完全分化的C9ORF72神经元还减少了扩增的含有G4C2重复的RNA和部分挽救的疾病表型。这些结果表明，EXOC2直接或间接调节含有G4C2重复序列的RNA的水平，使其成为C9ORF72-ALS/FTD的潜在治疗靶标。
