Fig. 6: Neuropeptide signals link olfactory neural circuit and fat metabolism.
a Inactivation of either neuropeptide processing enzyme egl-21–carboxypeptidase E homolog, or neuropeptide secretion factor unc-31–CAPS homolog suppresses the increased fat storage in the daf-11 mutants. Representative SRS images are in Supplementary Fig. 6k. b Among the neuropeptides that are secreted from AIY interneurons, deletion of flp-1, not flp-18, suppresses the increased fat storage in the daf-11 mutants. Representative SRS images are in Supplementary Fig. 6l. c AIY-specific overexpression of flp-1 increases fat storage under WT conditions. Restoration of flp-1 expression only in AIY neurons is sufficient to rescue fat storage increase in the daf-11; flp-1 double mutants. Representative SRS images are in Supplementary Fig. 6m. d Mutation of either flp-1 neuropeptide or its putative receptor npr-4 fully suppresses the fat storage increase conferred by the 2-butanone odor exposure. Representative SRS images are in Supplementary Fig. 6n. e Scheme of FLP-1 neuropeptides released from AIY interneurons acting through their putative receptor, NPR-4 that cell-autonomously regulates fat levels in the lipid storage tissue. f Inactivation of the npr-4 neuropeptide receptor suppresses the fat storage increase in the daf-11 mutants. Restoration of npr-4 expression specifically in the intestine is sufficient to increase the fat storage in the daf-11; npr-4 double mutants. Representative SRS images are in Supplementary Fig. 6o. g NPR-4 is required for the increased fat storage in the daf-11 and the nsy-5 mutants, that lack AWCON neurons, and in the glc-3 mutants with active AIY neurons. Representative SRS images are in Supplementary Fig. 7a. For a and b, data are mean ± s.d., **P < 0.01, ***P < 0.001, n.s. not significant by one-way ANOVA with Tukey’s multiple comparison test. For c, d, f, g data are mean ± s.d., ***P < 0.001, n.s. not significant by two-way ANOVA with Sidak’s multiple comparison test. Numbers of animals used are listed in Supplementary Data 1. For a–d, f, g source data are provided as a Source Data file.
