Journal Article

Mini-dCas13X–mediated RNA editing restores dystrophin expression in a humanized mouse model of Duchenne muscular dystrophy

Liu, Yuanhua, Shi, Linyu, Lin, Jiajia, Wang, Ning, Wang, Xing, Ying, Wenqin, Xu, Chunlong, Yang, Dong, Wang, Haoqiang, Zuo, Erwei, Chen, Wanjin, Yang, Hui, Xiao, Qingquan, Li, Zhifang, Jin, Ming, Xie, Long, Li, Guoling

2023

Overview

Approximately 10% of monogenic diseases are caused by nonsense point mutations that generate premature termination codons (PTCs), resulting in a truncated protein and nonsense-mediated decay of the mutant mRNAs. Here, we demonstrate a mini-dCas13X-mediated RNA adenine base editing (mxABE) strategy to treat nonsense mutation-related monogenic diseases via A-to-G editing in a genetically humanized mouse model of Duchenne muscular dystrophy (DMD). Initially, we identified a nonsense point mutation (c.4174C>T, p.Gln1392*) in the DMD gene of a patient and validated its pathogenicity in humanized mice. In this model, mxABE packaged in a single adeno-associated virus (AAV) reached A-to-G editing rates up to 84% in vivo, at least 20-fold greater than rates reported in previous studies using other RNA editing modalities. Furthermore, mxABE restored robust expression of dystrophin protein to over 50% of WT levels by enabling PTC read-through in multiple muscle tissues. Importantly, systemic delivery of mxABE by AAV also rescued dystrophin expression to averages of 37%, 6%, and 54% of WT levels in the diaphragm, tibialis anterior, and heart muscle, respectively, as well as rescued muscle function. Our data strongly suggest that mxABE-based strategies may be a viable new treatment modality for DMD and other monogenic diseases.

• Publisher: American Society for Clinical Investigation
• Subject: Analysis / Animals / Biomedical research / Cardiac muscle / Care and treatment / Codon / Codons / CRISPR-Cas Systems / Diaphragm / Disease Models, Animal / Duchenne muscular dystrophy / Duchenne's muscular dystrophy / Dystrophin / Dystrophin - genetics / Editing / Editors / Gene Editing - methods / Gene mutations / Gene therapy / Genetic aspects / Genetic research / Genetic Therapy - methods / Heart / Humans / Kinases / Mice / Muscle function / Muscle, Skeletal - metabolism / Muscular dystrophy / Muscular Dystrophy, Duchenne - genetics / Muscular Dystrophy, Duchenne - therapy / Mutation / Nonsense mutation / Pathogenicity / Patients / Point mutation / Proteins / RNA Editing / RNA processing / Skeletal muscle / Therapeutics / Utrophin