Widespread genome editing in the mammalian brain via peptide mediated delivery of CRISPR Cas9 ribonucleoprotein complexes

Gene editing offers the potential to correct or inactivate genes that lead to neurodegenerative diseases, but a key obstacle is the delivery of editing components to the CNS. Here we performed an in vivo screen for improved editing by CRISPR Cas9 ribonucleoprotein (RNP) complexes in the mouse brain. Optimal conditions for efficient and widespread editing in the mouse striatum were achieved by co injection of a self delivering RNP and a trafficking peptide designed to promote endosomal escape, which increased tissue retention and nuclear accumulation of the RNP without altering its initial distribution. Using these conditions, we observed up to 48 percent edited cells in a GFP reporter mouse and 20 percent deletion rates of a disease causing CAG repeat expansion in a mouse model of the neurodegenerative condition Huntingtons disease. These results indicate that peptide mediated RNP delivery provides an effective, non viral mechanism for widespread editing in the brain.The submitted data are sequences of a knockin mutant Huntingtin gene. The DNA was purified from the striatum of a mouse Huntington's disease model that had been treated with CRISPR Cas9 RNPs.