Fig. 7: Lipids secreted by IL-1β-stimulated neurons cause lipid droplet accumulation in Ttyh1-deficient astrocytes.

a Neuronal C1P production regulates TAG abundance in Drosophila heads. Each datapoint represents one cohort of ≥20 fly heads. Absorbance values from the colorimetric TAG assay were normalized to the mean of controls (Switch OFF). Number of independent lipid extracts (n) from fly heads is shown in brackets at the bottom of each bar. Unpaired two-tailed t-test (Cerk: t = 6.881, df = 12; Cerk-IR: t = 28.87, df = 4). b, c Loss of TTYH1 exacerbates IL-1β-lipids-induced lipid droplet (LD) accumulation in astrocytes. Shown are representative confocal images (b) and quantifications of BODIPY signals (c). Values were normalized to the mean of the ctrl-shR-naïve-lipids controls. One-way ANOVA (F = 11.79, df = 190) followed by Bonferroni’s multiple comparisons post hoc test. d Astrocytic Ttyh1 and neuronal C1P production are associated with the IL-1β-lipids-induced LD accumulation in astrocytes. Quantifications of BODIPY signals are shown. Values were normalized to the mean of Ttyh1 WT-naïve-lipids controls. One-way ANOVA (F = 11.79, df = 190) followed by Bonferroni’s multiple comparisons post hoc test. e Schematic representation of the neuron-astrocyte coculture system. f Ttyh1 KO astrocytes cocultured with IL-1β-stimulated neurons accumulate LDs. Shown are quantifications of BODIPY signals in astrocytes after coculture. Values were normalized to the mean of Ttyh1 WT-beads controls. One-way ANOVA (F = 4.395, df = 108) followed by Bonferroni’s multiple comparisons post hoc test. n.s. not significant, P > 0.9999. g Loss of Ttyh1 exacerbated TAG accumulation in astrocytes cocultured with IL-1β-stimulated neurons. TAG contents in astrocytes were measured after coculture. In C1P (+) groups, 0.5 µM C1P was added to the coculture medium. Absorbance values from the colorimetric TAG assay were normalized to the mean of Ttyh1 WT-naïve-ctrl-shR controls. Number of independent lipid extracts (n) from ≥3 independent experiments is shown in brackets at the bottom of each bar. One-way ANOVA (F = 937.6, df = 77) followed by Bonferroni’s multiple comparisons post hoc test. ***P < 0.001. Violin plots in (c–f) represent median (solid line), interquartile range (dotted line), and probability density of data (smoothed shape). Number of astrocytes (n) from ≥3 independent experiments is shown in brackets underneath each violin plot. Bar charts in (a, g) represent mean ±  SEM. Source data are provided as a Source Data file.