Genetics of cystogenesis in base edited human organoids reveal therapeutic strategies for polycystic kidney disease

SUMMARYIn polycystic kidney disease (PKD), microscopic tubules expand into macroscopic cysts. Among the world s most common genetic disorders, PKD is inherited via heterozygous loss-of-function mutations, but theorized to require additional loss-of-function. To test this, we establish human pluripotent stem cells in allelic series representing four common nonsense mutations, using CRISPR base editing. When differentiated into kidney organoids, homozygous mutants spontaneously form cysts, whereas heterozygous mutants (original or base-corrected) express no phenotype. Using these, we identify eukaryotic ribosomal selective glycosides (ERSGs) as PKD therapeutics enabling ribosomal read-through of these same nonsense mutations. Two different ERSGs not only prevent cyst initiation, but also limit growth of pre-formed cysts, by partially restoring polycystin expression. Glycosides also accumulate in cyst epithelia in organoids and mice. Our findings define the human polycystin threshold as a surmountable drug target for pharmacological or gene therapy interventions, with relevance for understanding disease mechanism and future clinical trials.