Generation of iPSC-derived human venous endothelial cells for the modeling of vascular malformations and drug discovery.

Venous malformations (VMs) represent prevalent vascular anomalies typically attributed to non-inherited somatic mutations within venous endothelial cells (VECs). The lack of robust disease models for VMs impedes drug discovery. Here, we devise a robust protocol for the generation of human induced VECs (iVECs) through manipulation of cell-cycle dynamics via the retinoic signaling pathway. We introduce an L914F mutation into the TIE2 gene locus of induced pluripotent stem cells (iPSCs) and show that the mutated iVECs form dilated blood vessels after transplantation into mice, thereby recapitulating the phenotypic characteristics observed in VMs. Moreover, utilizing a deep neural network and a high-throughput digital RNA with perturbation of genes sequencing (DRUG-seq) approach, we perform drug screening and demonstrate that bosutinib effectively rescues the disease phenotype in vitro and in vivo. In summary, by leveraging genome editing and stem cell technology, we generate VM models that enable the development of additional therapeutics.