Spatial and functional analysis of mouse pancreatic islets : β-cell-associated dextran uptake and δ-cell proximity under optogenetic stimulation

Sammanfattning

Pancreatic islets are clusters of endocrine cells that regulate blood glucose homeostasis through coordinated communication between different endocrine cell populations. Recent research suggests that spatial relationships between endocrine cells may influence β-cell activity and signalling dynamics within the islet microenvironment. The aim of this study was to investigate dextran uptake in mouse pancreatic islets under optogenetically stimulated and non-stimulated conditions. In addition, exploratory spatial analysis was performed to investigate the proximity between β-cell-associated regions and neighbouring δ cells under different experimental conditions. Mouse pancreatic islets were exposed to different glucose concentrations and optogenetic stimulation conditions before fluorescence imaging. Whole-islet analysis was performed on individual islets. Whole-islet analysis did not reveal statistically significant differences between experimental conditions. An exploratory ROI-level study was performed to investigate the dextran uptake within insulin-positive β-cell-associated regions. This analysis demonstrated heterogeneous dextran fluorescence patterns and revealed significant differences, however, these findings should be interpreted with caution due to pseudoreplication and the limited number of biological replicates. Exploratory spatial analysis did not reveal statistically significant differences in the proximity of β-cell-associated regions to neighbouring δ cells. Together, the findings suggest that dextran uptake and membrane trafficking activity within pancreatic islets may display local heterogeneity. The study further highlights the potential importance of spatial endocrine cell interactions within pancreatic islets and provides a foundation for future investigations using larger biological sample sizes and automated spatial analysis approaches.