Fig 2: ST2-dependent induction of chemotactic microglia is required for Aβ clearance upon IL-33 treatment.a,b, Chemotactic microglia migrate toward Aβ plaques after IL-33 treatment. Representative images (a) and violin plot (b) showing the distance between chemotactic microglia (that is, Vcam1+ Cx3cr1+ cells) and the nearest Aβ plaque 3, 8 and 24 h after IL-33 treatment (3 h: n = 83 microglia from four mice; 8 h: n = 92 microglia from four mice; 24 h: n = 89 microglia from four mice; Kruskal–Wallis test with Dunn’s multiple comparisons test). Dotted circle indicates 10 μm from the perimeter of the Aβ plaque. Arrowheads indicate Vcam1-expressing microglia. Scale bar = 10 μm. c,d, Genetic ablation of ST2 inhibits the microglial chemotactic state 3 h after IL-33 treatment. Representative contour plots (c) and bar plot (d) showing the proportions of chemotactic microglia in each group (Con APP/PS1;ST2WT mice: n = 4; IL-33–treated APP/PS1;ST2WT mice: n = 5; Con APP/PS1;ST2KO mice: n = 4; IL-33–treated APP/PS1 mice; ST2KO: n = 5; two-way ANOVA with Šidák’s multiple comparisons test). e–g, Genetic ablation of ST2 inhibits the induction of MHC-II+ phagocytic microglia 24 h after IL-33 treatment. Representative images (e) and bar plots showing the proportions of Aβ plaque-associated microglia (f) and phagocytic microglia (g) in each group (Con APP/PS1;ST2WT mice: n = 9 for panel f and n = 10 for panel g; IL-33-treated APP/PS1;ST2WT mice: n = 10 for panel f and n = 8 for panel g; Con APP/PS1;ST2KO mice: n = 8; IL-33-treated APP/PS1;ST2KO mice: n = 9; two-way ANOVA with Šidák’s multiple comparisons test). Arrowheads indicate phagocytic microglia. Scale bar = 20 μm. h,i, Genetic ablation of ST2 attenuates Aβ clearance induced by IL-33 48 h treatment. Representative images (h) and bar plot (i) showing the Aβ plaque area in the cortex 48 h after IL-33 treatment in each group (Con APP/PS1;ST2WT mice: n = 10; IL-33-treated APP/PS1;ST2WT mice: n = 9; Con APP/PS1;ST2KO mice: n = 9; IL-33–treated APP/PS1;ST2KO mice: n = 7; two-way ANOVA with Šidák’s multiple comparisons test). Scale bar = 200 μm. All data are mean ± s.e.m.Source data

Fig 3: ApoE is a chemoattractant that directs VCAM1-dependent chemotaxis of microglia.a, STRINGdb protein–protein interaction between VCAM1 (green) and Aß plaque-associated proteins (orange). b, Schematic diagram showing the protocol for injecting protein-coated beads followed by IL-33 treatment in APP/PS1 mice. c–e, Representative images (c) and bar plots showing the numbers of microglia (d) and MHC-II+ microglia (e) within the area of BSA-, ApoE-, CD44-, and ITGB2-coated beads after IL-33 treatment (Con: BSA: n = 3, ApoE: n = 6, CD44: n = 6, ITGB2: n = 4; IL-33: BSA: n = 5, ApoE: n = 6, CD44: n = 6, ITGB2: n = 5; two-way ANOVA with Šidák’s multiple comparisons test). Dotted line indicates bead area. Scale bar = 20 µm. f, Representative images showing the Vcam1-expressing microglia surrounding ApoE-coated beads after IL-33 treatment. Arrowheads indicate Vcam1-expressing microglia. Scale bars = 50 µm (left) and 20 µm (right). Experiment was repeated for three batches with similar results. g–i, Representative images (g) and bar plots showing the numbers of microglia (h) and MHC-II+ microglia (i) within the areas of beads coated with nonlipidated or lipidated ApoE in IL-33-treated APP/PS1 mice (nonlipidated: n = 7; lipidated: n = 7; two-tailed paired t-test). Dotted line indicates bead area. Scale bar = 20 µm. j–o, VCAM1 is essential for the ApoE chemotaxis of microglia after IL-33 treatment. j–l, Representative images (j) and bar plots showing the numbers of microglia (k) and MHC-II+ microglia (l) within the ApoE-coated bead areas after co-injection of rVCAM1 in IL-33-treated APP/PS1 mice (Fc: n = 6; rVCAM1: n = 6; two-tailed paired t-test). Dotted line indicates bead area. Scale bar = 20 µm. m–o, Representative images (m) and bar plots showing the numbers of microglia (n) and MHC-II+ microglia (o) within the ApoE-coated bead areas in IL-33-treated APP/PS1;VCAM1-icKO mice (wild-type [WT]: n = 6; icKO: n = 6; two-tailed unpaired t-test). Dotted line indicates bead area. Scale bar = 20 µm. All data are mean ± s.e.m.Source data

Fig 4: Dysregulated VCAM1 signaling is associated with impaired microglial infiltration into Aß plaques in patients with AD.a–c, Soluble VCAM1 (sVCAM1) level is elevated in the plasma of patients with AD and correlated with disease severity. a, sVCAM1 levels in the plasma of normal controls (NCs) and patients with AD (NC: n = 15; AD: n = 17; two-tailed Mann–Whitney test). b,c, Correlations between plasma levels of sVCAM1 and plasma p-Tau181 (b) (tau phosphorylated at threonine-181) and plasma NfL (c) (neurofilament light polypeptide) (n = 30 for panel b, n = 31 for panel c; linear regression). Dotted line indicates the 95% confidence interval of the regression line. d–f, Cerebrospinal fluid (CSF) sVCAM1 levels are inversely correlated with microglial infiltration into Aß plaques. Representative images (d) and dot plot (e) showing the correlation between CSF sVCAM1 level and microglial infiltration into Aß plaques in patients with AD (n = 26, linear regression). Dotted line indicates the 95% confidence interval of the regression line. Scale bar = 20 µm. f, Dot plot showing the correlations between CSF sVCAM1 level and microglial infiltration into Aß plaques in patients with AD stratified by ApoE4 genotype. All data are mean ± s.e.m.Source data

Fig 5: Macrophage sub-populations in bone-metastatic PC. Data related to Fig. 3. (A) Enriched pathways of Isg15+ MAM based on differentially expressed genes. (B) Enriched pathways of Inflam-Mono based on differentially expressed genes. (C) Enriched pathways of RTM based on differentially expressed genes. (D) Enriched pathways of Ftl1+ based on differentially expressed genes. (E) Enriched pathways of proliferating monocyte (Prolif-Mono) based on differentially expressed genes. (F) Representative flow cytometry dot plots showing the percentage of SSCloF4/80+ macrophages (gated cells) in total CD45+ cells from bone metastasis samples in CD169-DTR mice collected on day 14 with DT and Glu-DT (control toxin) treatment (n = 3). (G) Quantification of FACS data showing the percentage of SSCloF4/80+ macrophages (gated as in F) in total CD45+ cells from bone metastasis samples in CD169-DTR mice collected on day 14 with DT and Glu-DT (control toxin) treatment (n = 3). (H) Representative flow cytometry dot plots showing the depletion efficiency of bone marrow resident macrophages (CD169+CD106+) of all F4/80+ macrophages from F. (I) Representative TRAP staining of MycCaP-Bo bone metastasis in WT mice with indicated treatments for 18 d. (J) Representative TRAP staining of MycCaP-Bo bone metastasis in CD169-DTR mice with indicated treatments for 18 d. (K) Representative TRAP staining of MycCaP-Bo bone metastasis in Ccr2-/- mice with indicated treatments for 18 d. Data are mean ± SEM in G; *, P < 0.05. P value was calculated using two-tailed unpaired Student’s t test. Scale bar = 100 µm.