Figure 4. TREM-1 modulates Ly6C^hi classical monocyte trafficking and recruitment in the aortic wall following AngII stimulation via CD62L.

(A) Heatmap representation of chemokine receptors and adhesion molecule expression (expressed as mean metal intensity [MMI]), measured by mass cytometry on classical monocytes in blood and spleen of Apoe^–/–Trem1^+/+ and Apoe^–/–Trem1^–/– mice 1 day after AngII infusion (n = 4/group). Quantification of Ccl2, Ccl3, Ccl5, Ccr2, and Ccr5 mRNA expression in aortas of AngII-infused (B) Apoe^–/–Trem1^+/+ and Apoe^–/–Trem1^–/– mice (n = 9 in Apoe^–/–Trem1^+/+ group, n = 6 in Apoe^–/–Trem1^–/– group) and (C) isotype-treated or TREM-1 Ab–treated Apoe^–/– (n = 7 in isotype Ab group, n = 12 in TREM-1 Ab group) at day 7 after AngII infusion by RT-qPCR. (D) Representative SPADE tree plots of CD62L expression on classical Ly6C^hi monocytes (High) and Ly6C^lo monocytes (Low) in Apoe^–/–Trem1^+/+ and Apoe^–/–Trem1^–/– after 1 day of AngII infusion. (E) Flow cytometry analysis of CD62L expression on Ly6C^hi classical monocytes (n = 12 in isotype Ab group, n = 10 in TREM-1 Ab group) (F) Quantification of Sell mRNA expression by RT-qPCR in the aorta of TREM-1 Ab–treated or isotype Ab-treated Apoe^–/– mice after 3 days of AngII infusion (n = 7 in isotype Ab group, n = 12 in TREM-1 Ab group). (G–H) Apoe^–/– mice were implanted with subcutaneous osmotic minipumps releasing AngII (1000 ng/kg/min) and were treated intravenously with a neutralizing anti–CD62L antibody (CD62L Ab, 100 μg/mice/d) during the first 2 days and received intraperitoneal injection of either an anti-TREM-1 Ab or an isotype Ab (control) for 3 days. (G) CD62L blockade was confirmed on Ly6C^hi classical monocytes in the blood. (H) Quantification and representative dot plot of Ly6C^hi classical monocyte infiltration in the aorta by flow cytometry after 3 days of AngII infusion (n = 9 in isotype Ab group, n = 8 in TREM-1 Ab group). Results are displayed as the mean ± SEM. *P < 0.05, **P < 0.01, by Mann-Whitney test.