Tuberous sclerosis complex renal lesion pleiotropy arises from multiple aberrant developmental processes

Tuberous sclerosis complex (TSC) is a multisystem tumor-forming disorder caused by loss of TSC1 or TSC2. Renal manifestations predominately include cysts and angiomyolipomas. Despite a well-described monogenic etiology, the cellular pathogenesis has remained elusive. Here, we report a novel genetically-engineered human renal organoid model which recapitulates pleiotropic features of TSC kidney disease in vitro and upon orthotopic xenotransplantation. We find that loss of TSC1/2 affects multiple developmental processes in the renal epithelial, stromal, and glial compartments. First, loss of TSC1/2 leads to an expanded stroma by favouring stromal cell fate acquisition and alters terminal stromal cell identity. Second, epithelial cells in the TSC1/2-/- organoids exhibit a rapamycin-insensitive epithelial-to-mesenchymal transition. Third, a melanocytic population forms exclusively in TSC1/2-/- organoids, branching from MITF+ Schwann cell precursors of a bona fide neural crest-to-Schwann cell differentiation trajectory. Together, these results illustrate the pleiotropic developmental consequences of biallelic inactivation of TSC1/2 and offer insight into the pathogenesis of TSC kidney lesions. Overall design: scRNA-seq profiling of WT, TSC1-/-, and TSC2-/- renal organoids at day 9, 13, 17, and 21 of differentiation, from two cell lines (H9 and 168 1d2), preapred in mixes via MULTI-seq.