Reduced Blood Lipid Levels With In Vivo Crispr-Cas9 Base Editing Of Angptl3

Naturally occurring loss-of-function mutations in ANGPTL3 (angiopoietin-like 3) are associated with reduced blood triglycerides, low-density lipoprotein cholesterol, and risk of coronary heart disease, with no apparent adverse health consequences, making ANGPTL3 a compelling therapeutic target.1 We assessed whether base editing, a variation on CRISPR-Cas9 genome editing that does not require DNA double-strand breaks, could be used in vivo to introduce loss-of-function mutations into ANGPTL3 and reduce blood lipid levels. Base editor 3 (BE3) can introduce cytosine-to-thymine changes at desired sites in the genome,2 eg, nonsense mutations, into Pcsk9 (proprotein convertase subtilisin/kexin type 9) in mice.3 Animal studies and other procedures were performed as previously described3 in accordance with University of Pennsylvania guidelines.We screened potential sites of base-edited nonsense mutations in Angptl3 in Neuro-2a cells, identifying robust BE3 activity at the codon Gln-135 …