Engineered virus-like particles for in vivo gene editing ameliorate hearing loss in murine DFNA2 model

Although gene editing therapy is applicable to human diseases, its efficiency and safety require further investigation. Further, non-virus-mediated gene editor delivery is challenging in the inner ear. Here, engineered virus-like particles (eVLPs) were used for inner ear delivery of SpCas9 and single-guided RNA to delete the Kcnq4 dominant-negative mutant allele, which causes progressive hearing loss in a non-syndromic hearing loss murine model. eVLP-delivered SpCas9 was administered to the inner ears of Kcnq4^W277S/+ mice to target the Kcnq4-expressing outer hair cells (OHCs). Hearing loss was significantly alleviated 7 weeks after eVLP administration. OHC survival improved significantly, and OHC-innervating neurite (connected to type II spiral ganglion neuronal body) loss was ameliorated. Finally, OHC membrane potential was hyperpolarized with eVLP gene editor treatment in Kcnq4-mutant mice, indicating that their OHCs were healthier and more stable than those of uninjected mice. Our findings suggest that eVLPs are feasible inner ear gene editor deliverers to treat hearing loss.