Astrocyte-specific Drp1 cKO induces cortical astrocyte reactivity. (A) Overview of astrocyte-specific conditional Drp1 knockout mouse breeding strategy and timeline of tamoxifen administration. (B) Representative immunoblot for Drp1 from immunopurified astrocytes. COX4, a mitochondrial protein, serves as a loading control. Immunoblot ran in the same experiment as Fig. 7 I, therefore COX4 loading control image is the same as Fig. 7 I. (C) Quantification of Drp1 protein in isolated cKO and cWT astrocytes. N = 3 mice/condition. Data are mean ± SEM. Unpaired, two-tailed t test. (D) Representative images of Drp1 cWT and cKO V1 cortices at P21 with tdTomato⁺ astrocytes (magenta, first column), stained for GFAP (green, second column), and merged (third column). Scale bar, 100 µm. Zoom merge (last column). Scale bar, 20 µm. (E–H) Quantification of cortical tdTomato⁺ soma count of astrocyte density, (F) tdTomato⁺ astrocyte coverage normalized to astrocyte density, (G) GFAP soma count, and (H) GFAP coverage normalized to astrocyte density per layer in Drp1 cKO compared with cWT. N = 4 male and female mice/condition, 2–3 cortical images/mouse. Data are mean ± SEM. Two-way ANOVA with Sidak’s multiple comparisons test. (I–L) Quantification of (I) GFAP, (J) vimentin, (K) LCN2, and (L) Cxcl10 mRNA from isolated Drp1 cKO and cWT astrocytes. N = 2–6 male and female mice/condition. Data are mean ± SEM. Unpaired two-tailed t test. Source data are available for this figure: SourceData F6.