Human induced pluripotent stem cell-derived kidney organoids have potential for disease modeling and to be developed into clinically transplantable auxiliary tissue. However, they lack a functional... Show moreHuman induced pluripotent stem cell-derived kidney organoids have potential for disease modeling and to be developed into clinically transplantable auxiliary tissue. However, they lack a functional vasculature, and the sparse endogenous endothelial cells (ECs) are lost upon prolonged culture in vitro, limiting maturation and applicability. Here, we use intracoelomic transplantation in chicken embryos followed by single-cell RNA sequencing and advanced imaging platforms to induce and study vasculogenesis in kidney organoids. We show expansion of human organoid-derived ECs that reorganize into perfused capillaries and form a chimeric vascular network with host-derived blood vessels. Ligand-receptor analysis infers extensive potential interactions of human ECs with perivascular cells upon transplantation, enabling vessel wall stabilization. Perfused glomeruli display maturation and morphogenesis to capillary loop stage. Our findings demonstrate the beneficial effect of vascularization on not only epithelial cell types, but also the mesenchymal compartment, inducing the expansion of ' on target ' perivascular stromal cells, which in turn are required for further maturation and stabilization of the neo-vasculature. The here described vasculogenic capacity of kidney organoids will have to be deployed to achieve meaningful glomerular maturation and kidney morphogenesis in vitro. Show less
Diabetes mellitus is amongst the leading causes of morbidity and mortality worldwide. Insulin-producing pancreatic β-cells are central in establishing adequate glucose regulation and loss of... Show moreDiabetes mellitus is amongst the leading causes of morbidity and mortality worldwide. Insulin-producing pancreatic β-cells are central in establishing adequate glucose regulation and loss of functional β-cells results in the development of diabetes. Although it was previously thought that fully differentiated cells cannot change phenotype, murine studies recently indicated that mature β-cells can change identity into other islet cells under conditions of (metabolic) stress.We present a novel agarose based microwell culture system that can be used for aggregate formation of human or rodent islet cells. We show that this platform provides reproducible results to study aggregation of primary human islet cells. Using this culture system together with β-cell specific lineage tracing, we find that mature human β-cells can spontaneously lose their identity and convert into glucagon-containing α-cells. We then used human pancreatic tissue from donors with T2DM and matched controls to explore loss of β-cell identity in T2DM. We report that cells indicative of loss of β-cell identity are found more frequently in tissue samples from donors with a history of T2DM. Finally, we show that Pax4 and GLP-1 receptor agonists can partially prevent loss of identity β-cell in our ex vivo model. Show less
