TY - JOUR T1 - Treatment of a metabolic liver disease by <em>in vivo</em> prime editing in mice JF - bioRxiv DO - 10.1101/2021.08.17.456632 SP - 2021.08.17.456632 AU - Desirée Böck AU - Tanja Rothgangl AU - Lukas Villiger AU - Lukas Schmidheini AU - Nicholas Mathis AU - Eleonora Ioannidi AU - Susanne Kreutzer AU - Zacharias Kontarakis AU - Nicole Rimann AU - Hiu Man Grisch-Chan AU - Beat Thöny AU - Gerald Schwank Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/08/17/2021.08.17.456632.abstract N2 - Prime editing is a highly versatile CRISPR-based genome editing technology with the potential to correct the vast majority of pathogenic mutations (1). However, correction of a disease phenotype in vivo in somatic tissues has not been demonstrated thus far. Here, we establish proof-of-concept for in vivo prime editing and repair the metabolic liver disease phenylketonuria (PKU) in mice. We first developed a size-reduced SpCas9 prime editor (PE) lacking the RNaseH domain of the reverse transcriptase (PE2ΔRnH), and a linker- and NLS-optimized intein-split PE construct (PE2 p.1153) for delivery by adeno-associated virus (AAV) vectors. Systemic dual AAV-mediated delivery of this variant into the liver of neonatal mice enabled installation of a transversion mutation at the Dnmt1 locus with an average efficiency of 15%, and delivery of unsplit PE2ΔRnH using human adenoviral vector 5 (AdV5) further increased editing rates to 58%. PE2ΔRnH-encoding AdV5 was also used to correct the disease-causing mutation of the phenylalanine hydroxylase (Pah)enu2 allele in phenylketonuria (PKU) mice with an average efficiency of 8% (up to 17.3%), leading to therapeutic reduction of blood phenylalanine (L-Phe) levels. Our study demonstrates in vivo prime editing in the liver with high precision and editing rates sufficient to treat a number of metabolic liver diseases, emphasizing the potential of prime editing for future therapeutic applications.One Sentence Summary In vivo prime editing corrects phenylketonuria in mice.Competing Interest StatementD.B, L.V., and G.S are named on patent applications related to CRISPR-Cas technologies. ER -