DUSP4 regulates input to the suprachiasmatic circadian network via VIP-induced activation of the ERK1/2 pathway

Analysis of the genes and cellular signalling cascades mediating the response of SCN slices to vasoactive intestinal peptide (VIP). Primary goal was to find novel genes that may be involved in circadian phase shifting for further study. Promoter analysis of significantly regulated genes and gene ontology analysis would provide information into pathways VIP acts through in the SCN. Organotypic SCN slices from pups treated at circadian time (CT)10 with 1 µM vasoactive intestinal peptide (VIP) or vehicle, where CT12 is defined as the peak of PER2::LUC expression. 4 groups with 4 slices per group analysed: 1) T0: untreated, harvested at CT10. 2) T2 Veh: Treated with vehicle at CT10, harvested 2 h later at CT12. 3) T2 VIP: Treated with 1 µM VIP at CT10, harvested 2 h later. 4) T6 VIP: Treated with VIP at CT10, harvested 6 h later at CT12. T0 group acts as a baseline, T2 Veh acts as negative control. T2 VIP is main experimental/treatment group. T6 VIP provides longer term information on VIP treatment, and also acts as phase control for T2 Veh group.