Fig. 3: Chaski is the cortex glia monocarboxylate transporter required to provide ketone bodies to sustain ketone body-dependent associative memory.
From: Glia fuel neurons with locally synthesized ketone bodies to sustain memory under starvation
a, Inhibition of Chk expression in adult cortex glia impaired starved K-AM (F2,31 = 8.22, P = 0.001), while memory after massed training in fed flies was normal (F2,33 = 0.43, P = 0.653). b, BODIPY LD staining and quantification in starved and fed flies expressing or not the Chk RNAi in adult cortex glia. Inhibition of Chk expression in adult cortex glia in fed flies did not change LD mean area (t10 = 1.785, P = 0.105), whereas during starvation an increase in LD mean area was observed as compared to controls (t12 = 3.181, P = 0.008). c, Images of the Laconic sensor expressed in cortex glia with the Tub-Gal80ts;R54H02 driver, obtained by two-photon microscopy in the mTFP and Venus channels, under the same conditions as those used for live recordings. d, Application of 10 mM acetoacetate (red dashed line) resulted in a decreased Laconic ratio followed by a plateau in cortex glia of starved control flies, showing lactate efflux from cortex glia after acetoacetate bath application (mean trace ± s.e.m. of ten recordings per genotype). Quantification of the mean Laconic ratio at the plateau was performed during the last 100 s of recording (red line). Inhibition of Chk expression in adult cortex glia impaired this lactate efflux evoked by acetoacetate application (t18 = 2.791, P = 0.012). n indicated within the graph represents a group of 40–50 flies analysed together in a behavioural assay (a), one BODIPY-stained brain (b) or the response of a single recorded fly (d). Data are expressed as the mean ± s.e.m. with dots as individual values, and analysed by one-way ANOVA with post hoc testing by Newman–Keuls pairwise comparisons test (a) or by unpaired two-sided t-test (b and d). Asterisks refer to the least-significant P value of a post hoc comparison between the genotype of interest and the genotypic controls (a) or to the P value of the unpaired t-test comparison (b and d). **P < 0.001, *P < 0.05. Scale bar, 20 µm (b and c).
