Abstract
Maximizing the potential of human kidney organoids for drug testing and regenerative medicine and to model development and disease requires addressing cell immaturity, the lack of a mature collecting system, and off-target cell types. By independently generating two kidney progenitor cell populations-metanephric mesenchyme and ureteric bud (UB)-like cells-we could generate kidney organoids with a collecting system. We also identify the hormones aldosterone and arginine vasopressin (AVP) as critical to promote differentiation of collecting duct cell types including both principal cells (PCs) and intercalated cells (ICs). The resulting PCs express aquaporin-2 (AQP2) protein, which undergoes translocation to the apical membrane after vasopressin or forskolin stimulation. By single-cell RNA sequencing (scRNA-seq), we demonstrate improved proximal tubule maturation and reduced off-target cell populations. We also show appropriate downregulation of progenitor cell types, improved modeling of tubular injury, the presence of urothelium (Uro), and the ability of Notch pathway modulation to regulate PC:IC ratios during organoid development.