Functional, metabolic and transcriptional maturation of human pancreatic islets derived from stem cells

Transplantation of pancreatic islet cells derived from human pluripotent stem cells is a promising treatment for diabetes. Despite progress in the generation of stem-cell-derived islets (SC-islets), no detailed characterization of their functional properties has been conducted. Here, we generated functionally mature SC-islets using an optimized protocol and benchmarked them comprehensively against primary adult islets. Biphasic glucose-stimulated insulin secretion developed during in vitro maturation, associated with cytoarchitectural reorganization and the increasing presence of alpha cells. Electrophysiology, signaling and exocytosis of SC-islets were similar to those of adult islets. Glucose-responsive insulin secretion was achieved despite differences in glycolytic and mitochondrial glucose metabolism. Single-cell transcriptomics of SC-islets in vitro and throughout 6 months of engraftment in mice revealed a continuous maturation trajectory culminating in a transcriptional landscape closely resembling that of primary islets. Our thorough evaluation of SC-islet maturation highlights their advanced degree of functionality and supports their use in further efforts to understand and combat diabetes.

(f) Insulin content normalized to DNA content of the lysed SC-islets after static incubations (Supp. Fig.1j), One-way ANOVA i h Welch correc ion (g) Insulin secretion response to 72-minute stimulation with 17mM glucose (G17).
Normalized to secretion during 3mM glucose (G3) in the first 12 minutes of the test. n=3-4.
(h) Insulin secretion responses of S7w3 SC-islets to stimulation from 2.8 mM to 16.8 mM glucose (G3 to G17), 50 ng/ml exendin-4 (Ex4) and 30 mM KCl in perifusion. Comparison of two wildtype iPSC lines (n=2-3) and H1 hESC-line used in the rest of the study (n=18) (i) Insulin secretion in G3 as percentage of total insulin content during a 30-minute incubation in a static insulin secretion assay, comparison of different media compositions used throughout S7. One-a ANOVA i h Welch correc ion.
(j) Insulin secretion as percentage of total insulin content during 30-min incubations in G3, G17, 0.1 µM KATP-channel closing glibenclamide (GBC) and 30 mM KCl in a static test, n=3-8 for SC-islets, n=3 for primary islets, t-e i h Welch correc ion.
(l) Data in Figure 1l alternatively quantified as percentage of maximal secretion, plotted against the glucose concentration, statistics matrix shows significance for comparisons of the glucose concentration eliciting half-maximal secretion, n=4-6, One-way ANOVA.