CX3CR1 is a prerequisite for the development of cardiac hypertrophy and left ventricular dysfunction in mice upon transverse aortic constriction

Fig 1. Cx3cr1GFP/GFP mice exhibit a cardioprotective phenotype in response to chronic pressure overload. Using pressure volume measurement, the cardiac function of Cx3cr1GFP/GFP mice and Wt mice was evaluated 21 days after TAC or sham operation. (A, B) Ejection fraction and cardiac output are depicted as plots, more information is provided in Table 1. N = 6–8 mice/group; * above individual columns indicate significant differences between TAC and respective sham group; *P <0.05, **P<0.01, *** P<0.001.

Fig 2. CX3CR1 expression modulates the development of LV hypertrophy in response to pressure overload. (A) Heart-Weight/Body-Weight-Index of Wt and Cx3cr1GFP/GFP mice calculated 3, 6 and 21 days after transverse aortic constriction (TAC) and sham operation; n = 7–9 mice/group. (B) Aldolase mRNA expression pattern in LV tissue determined 3 and 6 days after TAC and sham operation in Wt and Cx3cr1GFP/GFP mice; n = 6–14 mice/group. (C) BNP mRNA expression pattern in LV tissue determined 3 and 6 days after TAC and sham operation in Wt and Cx3cr1GFP/GFP mice; n = 6–14 mice/group. (D) Representative sections of the left ventricle stained with sirious red of Wt and Cx3cr1GFP/GFP mice 21 days after TAC or Sham operation to determine cardiomyocyte size. Dashed lines highlight exemplary individual cardiomyocytes; scale bar indicating 50μm. Quantification of cardiomyocyte size by area planimetry; n = 5–6 mice/group, 4 slides per mouse were randomly analyzed by manual cell count of at least 50 cells/slide and mean was used for statistical analysis. * above individual columns indicate significant differences between TAC and respective sham group; **P<0.01, *** P<0.001, ****p < 0.0001.

Fig 3. CX3CR1 deficiency drives the immune response to a pro-inflammatory phenotype during chronic pressure overload. Quantification of Ly6Clow F4/80+ macrophages in the spleen and of (B) Ly6Clow and Ly6Chigh CD115+ monocytes in the blood of Wt and Cx3cr1GFP/GFP mice determined by flow cytometry 3 and 6 days after TAC and sham ioperation. (C-E) Number of neutrophils, Ly6Clow and Ly6Chigh macrophages in the LV tissue was determined by flow cytometry analysis in Cx3cr1GFP/GFP and Wt mice 3 and 6 days after TAC and sham operation. The particular cell subsets were defined as follows: neutrophils as CD45+ F4/80- Ly6G+, macrophages as CD45+ F4/80+ Ly6G-; Ly6Chigh and Ly6Clow macrophages were further discriminated according to the respective Ly6C surface expression; (F-I) Concentrations of the pro-inflammatory cytokines IL6 and IL-1β, the chemokine MCP1 and IL-10 were determined in LV tissue homogenates at day 3 and 6 after surgical intervention in Cx3cr1GFP/GFP and Wt mice using ELISA assays. (J-M) BrdU content of cardiac Ly6Chigh and Ly6Clow macrophages was determined by flow cytometry analysis at day 3 after TAC. BrdU was administered 18h before analysis. Histograms are based on…