Fig. 7: Dual neuron-glia metabolic exchange for LTM.
From: Glycolysis-derived alanine from glia fuels neuronal mitochondria for memory in Drosophila
a, Nebu KD in adult cortex glia impaired memory after spaced training (n = 14, F2,39 = 6.92, P = 0.003), but not after massed training (n = 12, F2,33 = 0.25, P = 0.78). b, Nicotine stimulation (50 µM, 30 s) increased glucose concentration in cortex glia. KD of nebu in adult cortex glia impaired the nicotine-induced glucose elevation (n = 10, t18 = 3.70, P = 0.002). c, The glucose concentration in MB neuron somata following the application of validamycin A (4 mM, dashed line) decreased faster in flies after spaced training compared to flies conditioned with a non-associative spaced unpaired training protocol (n = 15, t28 = 2.38, P = 0.025). Spaced training failed to elicit a faster glucose decrease in MB neurons upon nebu KD in adult cortex glia (n = 15, t28 = 1.10, P = 0.28). d, The basal glucose concentration increased in cortex glia following spaced training (n = 11–12, t21 = 3.08, P = 0.006). Spaced training failed to increase the basal glucose concentration in cortex glia when either nebu or InR was knocked down in cortex glia (nebu KD, n = 12 (control); n = 11 (5× spaced), t21 = 1.64, P = 0.12; InR KD, n = 11, t20 = 0.77, P = 0.45). e, ALAT KD in adult astrocyte-like glia impaired memory after spaced training (n = 12, F2,33 = 7.69, P = 0.002), but did not affect memory after massed training (n = 12, F2,33 = 0.25, P = 0.78). f, The increased in mitochondrial pyruvate flux elicited by spaced training (n = 10, t18 = 2.32, P = 0.03) was impaired by ALAT KD in adult astrocyte-like glia (n = 11 (control); n = 12 (5× spaced), t21 = 1.18, P = 0.25). g, Scheme of MB neurons-glia metabolic coupling upon LTM formation. All data are presented as mean ± s.e.m. Asterisks (*P < 0.05; **P < 0.01; NS, not significant, P > 0.05) illustrate the significance level of a two-sided t-test or of the least significant pairwise comparison following one-way ANOVA.
