β-Cell-Derived Extracellular Vesicles Boost β-Cell Functionality in Human Pancreatic Islets

Extracellular vesicles (EVs) are emerging therapeutic tools in nanomedicine, yet their effects in 2-dimensional (2D) versus 3D diabetes models remain underexplored. Unlike synthetic nanoparticles, EVs' cellular origin, innate bioactivity, and biological cargo make them attractive candidates for disease treatment. This study investigated whether β-cell-derived EVs enhance β-cell function, particularly insulin secretion. EVs were isolated from the human EndoC-βH1 β-cell line, characterized, and assessed for uptake by EndoC-βH1-derived spheroids and human donor pancreatic islets using confocal microscopy. The effect of EV uptake on spheroids and human islet function was determined through glucose-stimulated insulin secretion (GSIS) tests, enzyme-linked immunosorbent assay (ELISA), and quantitative polymerase chain reaction (qPCR) to compare insulin output and β-cell gene expression between EV-treated and untreated samples. Both spheroids and donor islets showed increased insulin production compared to controls. In spheroids, qPCR revealed elevated expression of PDX1 and SUR1. In contrast, EV-treated human islets exhibited a 3-fold increase in insulin secretion without significant changes in INS, PDX1, GCG, or SLC2A2 expression. Proteomic analysis further demonstrated enrichment in key proteins involved in β-cell function and survival in both EV-treated spheroids and islets. These findings suggest that β-cell-derived EVs can promote β-cell functionality in vitro by up-regulating key genes involved in insulin secretion. The results support the EndoC-βH1-derived spheroid model as a platform for studying human islet biology for advancing the preclinical development of EV-based therapies. This work offers new insights into the effects of β-cell-derived EVs in promoting β-cell functionality and highlights their potential to improve islet transplantation outcomes for patients with insulin-dependent type 1 diabetes.