Fig. 4: Ablation of Lcn2 abrogates the transformation of reactive astrocytes into myelin-laden phagocytes after dMCAO.

A Representative images showing the changes of the reactive astrocytes (GFAP, red) containing MBP-positive (green) myelin inclusions (white arrows) in lysosome (LAMP1, cyan) among demyelination lesion. Scale bar, 20 μm. B Immunostaining images of triple-labeled astrocytes (GFAP⁺, red) containing dMBP-positive (green) myelin fragments in LAMP1⁺ lysosome (cyan). White arrows indicated phagocytic astrocytes. Scale bar, 20 μm. C, D Quantification of triple-positive astrocytes obtained from immunofluorescence staining (n = 5 mice; adjusted **P < 0.0017, ***P < 0.0002 vs. WT sham; ^#P < 0.0083, ^###P < 0.0002 vs. WT dMCAO; two-way ANOVA, repeated-measures t-test). E Representative EM images of astrocytes in the ipsilateral CC of WT and Lcn2^−/− mice. Phagocytic inclusions with myelin-like structures were shown with red arrows. Scale bar, 5 μm. F Representative orthogonal views of Z-stack images obtained from two genotypes. GFAP⁺ (red) and Galectin3⁺ (blue) astrocytes engulfed dMBP⁺ (green) myelin debris after dMCAO. Scale bar, 20 μm. G Representative 3D images acquired from confocal images. Scale bar, 20 μm. H, I Quantifications showing the changes of co-positive (GFAP⁺ and Galectin3⁺) phagocytic astrocytes and phagocytic astrocytes containing myelin debris (GFAP⁺, Galectin3⁺ and dMBP⁺) (n = 5 mice; mean ± S.D.; adjusted **P < 0.0017, ***P < 0.0002 vs. WT sham; ^###P < 0.0002 vs. WT dMCAO; two-way ANOVA, repeated-measures t-test). J Quantification of the number of myelin debris contacted with or internalized by a single astrocyte according to 3D reconstruction images (n = 75 cells from five animals in each group; mean ± S.D.; adjusted ***P < 0.0002 vs. WT sham; ^###P < 0.0002 vs. WT dMCAO; two-way ANOVA, repeated-measures t-test). Source data are provided as a Source Data file.