In vivo base editing rescues ADPKD in a humanized mouse model

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic kidney disease, caused by mutations of the PKD1 and PKD2 genes, characterized by the development of renal cysts and extrarenal complications, such as cardiac hypertrophy. Recently, a revolutionary approach, adeno-associated virus (AAV) delivered CRISPR-Cas9 gene editing, has been developed to treat inherited diseases. However, the use of this technology in kidney diseases in vivo is challenged. In this study, we adapt one of the gene editing systems, adenine base editor (ABE9), to develop a broadly expressed and a kidney-specific promoter mediated base editors, and test the effects of these two systems delivered by AAV9 on preventing disease in humanized Pkd1^RC/RC mice carrying an arginine (R) to cystine (C) mutation that mimics a mutation in ADPKD patients. We show that one dose of the broadly expressed dual ABE9-AAV9 treatment corrects the pathogenic variant in kidneys, hearts and livers, and result in delaying cyst growth, decrease heart hypertrophy and improve liver function. To confirm the specificity of the base editor system in kidneys, we show that one dose of the kidney specific promoter mediated dual-ABE9-AAV9 treatment corrects the Pkd1 gene mutation in the kidney, and not in the heart, resulting in delaying cyst growth in Pkd1^RC/RC kidneys, supporting a promising strategy of using base editor to target specific organs. Treatment with ABE9 base editors mediated by either the broadly expressed or kidney specific promoter increased the survival rate of Pkd1^RC/null mice. These preclinical studies support a potential that single-dose genetic therapies may be through the correction of pathogenic variants to prevent ADPKD development in the clinic.