Improved specificity and efficacy of base-editing therapies with hybrid guide RNAs.

Phenylketonuria (PKU), hereditary tyrosinemia type 1 (HT1), and mucopolysaccharidosis type 1 (MPSI) are autosomal recessive disorders linked to the phenylalanine hydroxylase () gene, fumarylacetoacetate hydrolase () gene, and alpha-L-iduronidase () gene, respectively. Potential therapeutic strategies to ameliorate disease include corrective editing of pathogenic variants in the and genes and, as a variant-agnostic approach, inactivation of the 4-hydroxyphenylpyruvate dioxygenase () gene, a modifier of HT1, via adenine base editing. Here we evaluated the off-target editing profiles of therapeutic lead guide RNAs (gRNAs) that, when combined with adenine base editors correct the recurrent P281L variant, R408W variant, or W402X variant or disrupt the gene in human hepatocytes.

Epigenome Editing Durability Varies Widely Across Cardiovascular Disease Target Genes.

Background: Hepatic knockdown of the proprotein convertase subtilisin/kexin type 9 ( ) gene or the angiopoietin-like 3 ( ) gene has been demonstrated to reduce blood low-density lipoprotein cholesterol (LDL-C) levels, and hepatic knockdown of the angiotensinogen ( ) gene has been demonstrated to reduce blood pressure. Genome editing can productively target each of these three genes in hepatocytes in the liver, offering the possibility of durable "one-and-done" therapies for hypercholesterolemia and hypertension. However, concerns around making permanent gene sequence changes via DNA strand breaks might hinder acceptance of these therapies.