De Giorgi, MarcoLi, AngHurley, AyreaBarzi, MercedesDoerfler, Alexandria M.Cherayil, Nikitha A.Smith, Harrison E.Brown, Jonathan D.Lin, Charles Y.Bissig, Karl-DimiterBao, GangLagor, William R.2021-06-102021-06-102021De Giorgi, Marco, Li, Ang, Hurley, Ayrea, et al.. "Targeting the Apoa1 locus for liver-directed gene therapy." <i>Molecular Therapy - Methods & Clinical Development,</i> 21, (2021) Cell Press: 656-669. https://doi.org/10.1016/j.omtm.2021.04.011.https://hdl.handle.net/1911/110709Clinical application of somatic genome editing requires therapeutics that are generalizable to a broad range of patients. Targeted insertion of promoterless transgenes can ensure that edits are permanent and broadly applicable while minimizing risks of off-target integration. In the liver, the Albumin (Alb) locus is currently the only well-characterized site for promoterless transgene insertion. Here, we target the Apoa1 locus with adeno-associated viral (AAV) delivery of CRISPR-Cas9 and achieve rates of 6% to 16% of targeted hepatocytes, with no evidence of toxicity. We further show that the endogenous Apoa1 promoter can drive robust and sustained expression of therapeutic proteins, such as apolipoprotein E (APOE), dramatically reducing plasma lipids in a model of hypercholesterolemia. Finally, we demonstrate that Apoa1-targeted fumarylacetoacetate hydrolase (FAH) can correct and rescue the severe metabolic liver disease hereditary tyrosinemia type I. In summary, we identify and validate Apoa1 as a novel integration site that supports durable transgene expression in the liver for gene therapy applications.engThis is an open access article under the CC BY-NC-ND licenseJournal article1-s2-0-S2329050121000772-mainhttps://doi.org/10.1016/j.omtm.2021.04.011