HSD affects brain’s metabolism and causes lipid droplet accumulation.

(A) Schematic showing the cellular energy balance between glycolysis and mitochondrial OxPhos. Attenuation of glycolysis results in the up-regulation of OxPhos. (B) Mean basal mitochondrial OCR collected from single adult brains of ND and HSD-fed flies using Agilent Seahorse XF HS Mini Analyzer. N = 6 measurement cycles collected from 3 brains/treatment group. Student’s T test with Welch’s correction. (C) Mean basal ECAR collected from single adult brains of ND and HSD-fed flies using Agilent Seahorse XF HS Mini Analyzer. N = 6 measurement cycles collected from 3 brains/treatment group. Student’s T test with Welch’s correction. (D) Mean ratio of brain OCR/ECAR of ND and HSD-fed flies showing that the brains of ND-fed flies exhibit more glycolysis, whereas the brains of HSD-fed flies lean more towards OxPhos. (E) Confocal images of Ldh-GFP in the antennal lobe region (dotted circle) of ND and HSD-fed flies. (F) Mean Ldh-GFP fluorescent intensity, obtained from Z-stack summation projections, within a defined region of interest (dotted circle) that covers the antennal lobe in ND and HSD-fed flies. Student’s T test with Welch’s correction. N = each circle represents an individual fly. (G) Confocal images of Lipidtox-stained (white) lipid droplets in the brains of ND and HSD-fed flies that express membrane-tagged GFP in their ensheathing glia (yellow). (H) Mean Lipidtox fluorescent intensity extracted from within the ensheathing glia mask. Student’s T test with Welch’s correction. N = each circle represents an individual fly. The data underlying this figure can be found in the supporting information file S1 Data. ECAR, extracellular acidification rate; HSD, high-sugar diet; OCR, oxygen consumption rate; OxPhos, oxidative phosphorylation.