Muscle-specific gene editing therapy via mammalian fusogen-directed virus-like particles

Abstract Muscle genetic defects can lead to impaired movement, respiratory failure, and other severe symptoms. The development of curative therapies is challenging due to the need for the delivery of gene-editing tools into skeletal muscle cells throughout the body. Here, we used muscular fusogens (Myomaker and Myomerger) to engineer muscle-specific virus-like particles (MuVLPs) for the systemic delivery of gene-editing tools. We demonstrated that MuVLPs can be loaded with diverse payloads, including EGFP, Cre and Cas9/sgRNA ribonucleoproteins (Cas9 RNPs), and can be delivered into muscle cells via targeted membrane fusion. Systemic administration of MuVLPs carrying Cas9 RNPs enabled muscle-specific gene editing, which excised the exon containing a premature terminator codon mutation in mice with Duchenne muscular dystrophy. This treatment restored dystrophin expression in various muscle tissues, including the diaphragm, quadriceps, tibialis anterior, gastrocnemius, and triceps. As a result, the treated mice exhibited a significantly increased capacity for exercise and endurance. This study established a platform for precise gene editing in muscle tissues.