PFKFB3 inhibition restores β-cell responsiveness to acetylcholine in a 3xTg-AD pancreatic tissue-slice mode
The glycolytic regulator PFKFB3 supports dysfunctional {beta}-cell states, but its role in pancreatic Ca2+ signaling remains unclear. We examined responses to PFKFB3 inhibitors (AZ67, AZ26) in pancreatic tissue slices from aged 3xTg-AD mice, a model of Alzheimer's disease that develops impaired glucose tolerance and diabetes as comorbidity. Compared to wild-type controls, {beta}-cells showed weaker glucose-stimulated and acetylcholine-potentiated Ca2+ activity, accompanied by increased nuclear PFKFB3 positivity in insulin-defined islet-cell populations, used here as a PFKFB3-associated stress-state marker. During glucose and acetylcholine stimulation, AZ67 increased {beta}-cell Ca2+ event frequency while maintaining short events. In neighboring acinar cells, PFKFB3 inhibitor exposure was followed by renewed oscillations after acetylcholine-evoked activity had waned. {beta}-cell recruitment was preserved during adrenergic inhibition, and enhanced activity persisted after inhibitor withdrawal, although these recordings were exploratory and residual tissue drug exposure could not be excluded. An effect that survives both drug removal and adrenergic opposition identifies a Ca2+ signaling phenotype in 3xTg-AD {beta}-cells that is acutely inducible yet not transient, and establishes PFKFB3 as a regulator of muscarinic responsiveness in the stressed {beta}-cell.