Human gestational diabetes mellitus-derived exosomes impair glucose homeostasis in pregnant mice and stimulate functional maturation of offspring-islets

Aims: Pancreatic islets undergo critical development and functional maturation during the perinatal period when they are highly sensitive to microenvironment. We aim to determine the effects and mechanisms of gestational diabetes mellitus (GDM) hypermetabolic stress on glucose homeostasis in pregnant mice and functional maturation of the islets of their offspring. Main methods: Exosomes were extracted from the umbilical vein blood of individuals with or without GDM for administration to pregnant mice. The blood glucose, serum insulin, glycosylated hemoglobin, and lipopolysaccharide levels were measured in pregnant mice. The expression and localization of insulin, glucagon, PC1/3, PDX1, and p -S6 in the islets of neonatal rats were continuously monitored using immunofluorescence to evaluate their functional status. Primary islet cells were cultured and treated with GDM exosomes and exendin to determine the expression of GLP-1R, AKT, p-AKT, and p -S6 via western blotting. Key findings: GDM exosomes induced remarkable oral glucose intolerance, hyperinsulinemia, and metabolic inflammation in pregnant mice. The islets of GDM offspring exhibited high insulin, glucagon, PC1/3, PDX1, and p -S6 expression at and after birth, and activation of the local GLP-1/GLP-1R axis. The functional maturation of normal -offspring islets did not commence until after birth, while it was activated prior to birth in GDM offspring, seriously disrupting the whole process. GDM exosomes activated the GLP-1/GLP-1R axis between alpha and beta cells, and stimulated functional maturation of beta cells via the Akt-mTORC1-pS6 pathway. Significance: These findings provide preliminary insights into the mechanisms underlying the high incidence of diabetes in the offspring of mothers with GDM.