Fig. 7: SNS activation reverses the effects of PKC-δ-neurons’ inhibition on WAT browning under leucine deprivation.

a Norepinephrine (NE) levels in subcutaneous WAT (sWAT) measured by ELISA kit. b Tyrosine hydroxylase (TH) proteins in sWAT by western blotting (left) and quantified by densitometric analysis (right); A.U.: arbitrary units. c Gene expression of Adrb3 in sWAT by RT-PCR. d Fat mass by NMR. e sWAT weight. f Representative images of hematoxylin and eosin (H&E) staining of sWAT. g sWAT cell size quantified by Image J analysis of H&E images. h Gene expression of Ucp1, Pgc1a, Cidea, Dio2, and Prdm16 in sWAT by RT-PCR. i Representative images of immunohistochemistry (IHC) of UCP1 in sWAT. j UCP1 protein in sWAT by western blotting (top) and quantified by densitometric analysis (bottom). k Summary Diagram: WAT browning is induced by leucine deprivation, which is sensed by the amino acid sensor GCN2 in PKC-δ neurons of the amygdala. Activated GCN2 then subsequently stimulates ATF4 expression and increases the PKC-δ neuronal activity that promotes WAT browning via increasing the activity of the sympathetic nerve. Studies for a–c were conducted using 22- to 24-week-old male PKC-δ-Cre mice receiving AAVs expressing mCherry (PKC δ − hM4Di) or hM4Di (PKC δ + hM4Di), fed a control (Control) or leucine-deficient [(-) L] diet for 3 days; studies for d–j were conducted using 16- to 18-week-old male PKC δ − hM4Di or PKC δ + hM4Di mice injected with saline (−CL316) or CL316243 (+CL316), fed a (-) L diet for 3 days. Data are expressed as the mean ± SEM (n represents number of samples and are indicated above the bar graph), with individual data points. Data were analyzed by one-way ANOVA followed by the SNK (Student–Newman–Keuls) test. Source data are provided as a Source data file.