Fig. 4: Macrophage loss without local tissue damage is not sufficient to promote CAM renewal.

a, Representative time-lapse imaging of CAM replacement after targeted laser ablation (yellow asterisk) in Csf1r^eGFPR26^mTmG mice. Ablation was performed within a 500 µm² region (yellow dashed square). b, CAM replacement after systemic depletion through intraperitoneal injection of diphtheria toxin (DT) (25 ng per g body weight) in Cx3cr1^DTR mice. c, Serial imaging of single lineage-traced macrophages in Cx3cr1^creERT2R26^dsRedCsf1r^eGFP mice under homeostasis. Mice received a single low-dose tamoxifen intraperitoneal injection (50 µg), and were imaged weekly for 2 weeks. d, Quantification of CAM niche replenishment under different conditions: 2-week laser-induced loss (n = 44 CAMs, 4 mice), 8-week laser-induced loss (n = 261 CAMs, 4 mice), DT-induced loss (n = 53 CAMs, 3 mice), homeostatic loss (n = 29 CAMs, 3 mice) or laser-induced CAM loss with capillary clot (n = 25 CAMs, 4 mice). Data were analysed using one-way ANOVA with Tukey’s test. Data are mean ± s.d. e, Schematic of CAM replacement after laser-induced CAM loss with capillary damage in Csf1r^eGFPCcr2^RFP/+ and Ccr2^RFP/RFP mice. f, Quantification of CAM replenishment (Csf1r^eGFP-positive cells) after niche damage at 2 weeks in Ccr2^RFP/+ versus Ccr2^RFP/RFP mice. n = 4 mice per group; two 500 µm² regions per mouse. Statistical analysis was performed using two-way RM-ANOVA with Fisher’s test. Data are mean ± s.d. g, Representative imaging of CAM replacement after regional capillary niche damage. h, Lineage-tracing analysis of single CAMs in Cx3cr1^creERT2R26^nTnG mice after capillary injury. i, Quantification of CAM proliferation based on proximity to capillary damage. n = 25 CAMs in damaged regions; 4 mice. Statistical analysis was performed using paired Student’s t-tests at day 7 (D7). Data are mean with paired lines. Scale bars, 50 µm.

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