Cas9實現基因治療Angelman症候群
作者：
小柯機器人發布時間：2020/10/23 14:36:01
美國北卡羅萊納大學教堂山分校Mark J. Zylka小組利用Cas9實現基因治療Angelman症候群。相關論文於2020年10月21日在線發表於國際學術期刊《自然》。
據研究人員介紹，Angelman症候群（AS）是由母親遺傳的UBE3A等位基因突變或缺失引起的嚴重神經發育障礙。在神經元中，父系繼承的UBE3A等位基因被稱為UBE3A-ATS的長非編碼RNA順式沉默。
作為系統篩選的一部分，研究人員發現當靶向Snord115基因（聚集在Ube3a-ATS 3'區的小核仁RNA）時，Cas9可用於激活培養的小鼠和人類神經元中的父系Ube3a（「去沉默」）。靶向約75個Snord115基因的短Cas9變體和嚮導RNA被包裝到腺相關病毒中，並在胚胎和出生後早期階段被應用於AS的小鼠模型，預計恢復Ube3a的治療益處將會最大。這種早期治療使整個父親的父親Ube3a沉默了至少17個月，並挽救了AS小鼠的解剖學和行為表型。腺相關病毒載體基因組整合到Cas9目標位點中，導致Ube3a-ATS在載體來源的polyA盒中提前終止，或者在反向整合時，通過與載體衍生的Cas9轉錄物的轉錄碰撞而終止。
這項研究表明，基因治療載體的靶向基因組整合可以在整個生命中恢復父系繼承的UBE3A的功能，為症候群神經發育障礙的疾病緩解提供了途徑。
附：英文原文
Title: Cas9 gene therapy for Angelman syndrome traps Ube3a-ATS long non-coding RNA
Author: Justin M. Wolter, Hanqian Mao, Giulia Fragola, Jeremy M. Simon, James L. Krantz, Hannah O. Bazick, Baris Oztemiz, Jason L. Stein, Mark J. Zylka
Issue&Volume: 2020-10-21
Abstract: Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by a mutation or deletion of the maternally inherited UBE3A allele. In neurons, the paternally inherited UBE3A allele is silenced in cis by a long non-coding RNA called UBE3A-ATS. Here, as part of a systematic screen, we found that Cas9 can be used to activate ('unsilence') paternal Ube3a in cultured mouse and human neurons when targeted to Snord115 genes, which are small nucleolar RNAs that are clustered in the 3′ region of Ube3a-ATS. A short Cas9 variant and guide RNA that target about 75 Snord115 genes were packaged into an adeno-associated virus and administered to a mouse model of AS during the embryonic and early postnatal stages, when the therapeutic benefit of restoring Ube3a is predicted to be greatest1,2. This early treatment unsilenced paternal Ube3a throughout the brain for at least 17 months and rescued anatomical and behavioural phenotypes in AS mice. Genomic integration of the adeno-associated virus vector into Cas9 target sites caused premature termination of Ube3a-ATS at the vector-derived polyA cassette, or when integrated in the reverse orientation, by transcriptional collision with the vector-derived Cas9 transcript. Our study shows that targeted genomic integration of a gene therapy vector can restore the function of paternally inherited UBE3A throughout life, providing a path towards a disease-modifying treatment for a syndromic neurodevelopmental disorder.
DOI: 10.1038/s41586-020-2835-2
Source: https://www.nature.com/articles/s41586-020-2835-2