Adipocyte-derived extracellular vesicles increase insulin secretion through transport of insulinotropic protein cargo

Extracellular vesicles are membranous nanoparticles that convey signaling between cells, tissues and organs. By applying fluorescence tracing and SILAC-labeling paired with (phospho)proteomics, we identified the transfer of functional insulinotropic protein cargo via adipocyte-derived extracellular vesicles (AdEVs) from adipose tissue to pancreatic ß-cells in vivo and in vitro. AdEV-derived proteins were targets for phosphorylation, increased the overall abundances and phosphosite dynamics of insulinotropic GPCR/cAMP/PKA pathways and amplified 1st-phase glucose-stimulated insulin secretion (GSIS) in murine islets. Notably, insulinotropic effects were restricted to AdEVs from obese and insulin resistant, but not lean mice, which was consistent with differential protein loads and AdEV luminal morphologies. Pre-treatment with AdEVs from obese mice amplified insulin secretion and glucose tolerance in mice independent from hyperglycemia. These data suggest that secreted AdEVs can inform pancreatic ß-cells about adipose tissue insulin resistance in order to amplify GSIS in times of increased insulin demand.