Figure 6: Fibrinogen induces recruitment of peripheral macrophages into the CNS via CD11b/CD18-mediated upregulation of CCL2.

(a) Infiltration of peripheral Ccr2⁺ macrophages (RFP, red) in the corpus callosum 7 days after fibrinogen injection in Ccr2^RFP/+Cx3cr1^GFP/+. Scale bar, 200 μm. Quantification of RFP (top graph) and GFP (bottom graph) intensity in the same sections of corpus callosum of ACSF- or fibrinogen-injected Ccr2^RFP/+Cx3cr1^GFP/+mice on days 1, 3 and 7. Data are presented as mean±s.e.m. (n=4–6 mice per time point). *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001 (two-way ANOVA and Bonferroni’s multiple comparisons test). (b) Infiltration of peripheral Ccr2⁺ macrophages (RFP, red) in the corpus callosum 7 days after fibrinogen injection in Ccr2^RFP/+- and Ccr2-deficient (Ccr2^RFP/RFP) mice at 7 days post-fibrinogen injection. Scale bar, 50 μm. Quantification of infiltrated CD3⁺ T cells (top graph) and demyelinated area (bottom graph) in the corpus callosum of Ccr2^RFP/+- and Ccr2-deficient (Ccr2^RFP/RFP) mice 7 days after fibrinogen injection. Data are presented as mean±s.e.m. (n=6–7 mice per group). **P<0.01 (non-parametric Mann–Whitney U-test). (c) Real-time PCR analysis of Ccl2 gene expression in corpus callosum 12 h after injection of ACSF and plasma obtained from WT, Fibγ^390–396A Fib^−/− or mice. Data are presented as mean±s.e.m. (n=4 mice per group). *P<0.05, **P<0.01 (one-way ANOVA and Bonferroni’s multiple comparisons test). ANOVA, analysis of variance; d, days.