Periphery signals generated by Piezo-mediated stomach stretch and Neuromedin-mediated glucose load regulate the Drosophila brain nutrient sensor

Nutrient sensors allow animals to identify foods rich in specific nutrients. The Drosophila nutrient sensor, diuretic hormone 44 (DH44) neurons, helps the fly to detect nutritive sugar. This sensor becomes operational during starvation; however, the mechanisms by which DH44 neurons or other nutrient sensors are regulated remain unclear. Here, we identified two satiety signals that inhibit DH44 neurons: (1) Piezo-mediated stomach/crop stretch after food ingestion and (2) Neuromedin/Hugin neurosecretory neurons in the ventral nerve cord (VNC) activated by an increase in the internal glucose level. A subset of Piezo(+) neurons that express DH44 neuropeptide project to the crop. We found that DH44 neuronal activity and food intake were stimulated following a knockdown of piezo in DH44 neurons or silencing of Hugin neurons in the VNC, even in fed flies. Together, we propose that these two qualitatively distinct peripheral signals work in concert to regulate the DH44 nutrient sensor during the fed state.

Automated summary

Two satiety signals inhibiting DH44 nutrient sensor activity have been identified: Piezo-mediated stomach/crop stretch and Neuromedin/Hugin neurosecretory neurons activated by an increase in internal glucose levels. These signals work together to regulate DH44 sensor activity in fed flies.