Figure 5

Cx3cr1 knockout hampers the transient selective increase in CD64⁺ CCR2^- Ly6C^low MHCII^low Mφ detected in WT mice during ECH, suppresses iso-induced concentric hypertrophy and accelerates dilation and alteration of function. (A) Experimental procedure (B) Typical flow cytometry gating strategy to identify cardiac Mφ subpopulations. Cells were isolated from collagenase digested hearts and stained with the indicated antibodies before analysis. CD45⁺ leukocytes were identified, doublets excluded (by FSC-W vs. SSCA). Live CD45⁺ cells (after PI exclusion) were gated on CD11b⁺ CD64⁺ Mφ. CD11b⁺ CD64⁺ Mφ were further analyzed on their pattern of expression of CCR2 vs Ly6C and CCR2^- Ly6C^low cells were gated on MHCII^high and MHCII^low cells. Quantification of immune cells n = 4–7 cell isolation, two-way ANOVA followed by Sidak’s post-hoc tests. * p < 0.05 vs WT at the same time point. (C) Kinetics of echocardiography parameters in WT or Cx3cr1^-/- mice implanted with Iso pump at day 0. n = 14–38 mice, Two-way ANOVA followed by Sidak’s post-hoc tests. * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001 vs WT at the same time point. (D) Geometric parameter h/r versus HW n = 7–26 mice/group. (E) Cardiomyocyte cross-sectional area estimated in cardiac sections stained with WGA (typical image). Mean ± SEM from 6 mice/group, sacrificed at day14. Mann–Whitney U test. ** p < 0.001.