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

Adipocyte-derived extracellular vesicles (AdEVs) are membranous nanoparticles that convey communication from adipose tissue to other organs. Here, to delineate their role as messengers with glucoregulatory nature, we paired fluorescence AdEV-tracing and SILAC-labeling with (phospho)proteomics, and revealed that AdEVs transfer functional insulinotropic protein cargo into pancreatic & beta;-cells. Upon transfer, AdEV proteins were subjects for phosphorylation, augmented insulinotropic GPCR/cAMP/PKA signaling by increasing total protein abundances and phosphosite dynamics, and ultimately enhanced 1st-phase glucose-stimulated insulin secretion (GSIS) in murine islets. Notably, insulinotropic effects were restricted to AdEVs isolated from obese and insulin resistant, but not lean mice, which was consistent with differential protein loads and AdEV luminal morphologies. Likewise, in vivo pre-treatment with AdEVs from obese but not lean mice amplified insulin secretion and glucose tolerance in mice. This data suggests that secreted AdEVs can inform pancreatic & beta;-cells about insulin resistance in adipose tissue in order to amplify GSIS in times of increased insulin demand. Extracellular vesicles (EVs) convey inter-organ communication in health and disease. Here, the authors report that adipocyte-derived EVs isolated from insulin-resistant obese but not lean male mice stimulate insulin secretion via the targeted transfer of insulinotropic proteins from adipose tissue to & beta;-cells.

Automated summary

Extracellular vesicles (EVs) derived from adipocytes transfer insulinotropic proteins to pancreatic β-cells, enhancing insulin secretion and glucose tolerance. This process is observed in insulin-resistant obese mice, suggesting that AdEVs play a role in informing β-cells about insulin resistance and increasing insulin demand.