Lipid Nanoparticles for the Delivery of CRISPR/Cas9 Machinery to Enable Site-Specific Integration of CFTR and Mutation-Agnostic Disease Rescue

Abstract

We report the engineering of lipid nanoparticles (LNPs) to transport CRISPR/Cas9 payloads, including double-stranded DNA (dsDNA) donor templates, designed for homology directed repair (HDR)-mediated site-specific insertion of the cystic fibrosis transmembrane conductance regulator (CFTR) gene to correct cystic fibrosis (CF) in diseased airway epithelium. We screened various nanoparticle formulations, adjusting ratios of Cas9-encoding mRNA, single guide RNAs (sgRNAs), and dsDNA donor templates to optimize gene editing using human bronchial epithelial cells (16HBE14o-) harboring a CF-causing mutation (G542X). Populations of G542X cells edited via LNP delivery of CFTR donors achieved 3 - 3.5% gene integration and yielded comparable CFTR protein expression compared to normal 16HBE14o- controls. These edited populations exhibit restoration of CFTR-dependent Cl- current to ca. 80% of values measured in normal 16HBE14o- cell monolayers. This LNP platform adds capabilities for transporting large gene editing machinery to airway epithelial cells for genomic integration of entire genes, enabling therapeutic solutions that achieve correction of any CF-causing mutation.