Vascularization of pluripotent stem cell-derived islet organoids improves β-cell function

Blood vessels play a critical role in pancreatic islet health and function, yet current culture methods to generate islet organoids from human pluripotent stem cells (SC-islets) lack a vascular component. Here, we engineered 3D vascularized SC-islet organoids by assembling SC-islet cells, human primary endothelial cells (ECs) and fibroblasts both in a non-perfused model and a microfluidic device with perfused vessels. Vasculature improved stimulus-dependent Ca2+ influx into SC-β-cells; a hallmark of β-cell function that is blunted in non-vascularized SC-islets. We show that an islet-like basement membrane is formed by vasculature and contributes to the functional improvement of SC-β-cells. Furthermore, cell-cell communication networks based on scRNA-seq data predicted BMP2/4-BMPR2 signaling from ECs to SC-β-cells. Correspondingly, BMP4 augmented the SC-β-cell Ca2+ response and insulin secretion. The here-described vascularized SC-islet models will enable further studies of crosstalk between β-cells and ECs and serve as an in vivo-mimicking platform for disease modeling and therapeutic testing. In this analysis, we used single-cell RNA-seq (scRNA-seq) to profile 1809 vasculature forming cells (endothelial cells and fibroblasts). We annotate cell types based on the known marker genes. Through cell-cell communication network analyses, we predicted heterotypic cell-cell interactions between beta cells, endothelial cells and fibroblasts.