Monitoring Autophagic Flux in vivo Revealed its Physiological Response and Significance of Heterogeneity in Pancreatic Beta Cells

Autophagy plays an important role in preserving cellular homeostasis in pancreatic beta cells. However, the extent of autophagic flux induced in various physiological settings in vivo is unclear. In this study, we generated transgenic mice expressing pHluorin-LC3-mCherry reporter for monitoring systemic autophagic flux. Our findings revealed that autophagic flux in pancreatic islets enhanced after starvation, although suppression of the flux after short-term refeeding needs more prolonged restarvation in islets than in liver and skeletal muscle. Furthermore, heterogeneity of autophagic flux in beta cells manifested after increasing insulin resistance and intracellular calcium influx by glucose stimulation increased more in high- than low-flux beta cells, with differential gene expression based on the flux. Thus, our monitor mouse enables us to reveal physiological response and biological insight of heterogeneity in autophagic flux in pancreatic beta cells.