Figure 2: TREM-1 drives skewed monocyte differentiation and HFCD-dependent monocytosis.
From: TREM-1 links dyslipidemia to inflammation and lipid deposition in atherosclerosis
(a) Absolute numbers of peripheral blood myeloid cell subsets before HFCD feeding (week 0; n=4), after 4 weeks of HFCD-feeding (n=4–5), after 16 weeks of HFCD-feeding (n=13–15) and after 16 weeks of chow-feeding (n=9–13) as determined by flow cytometry. Circles represent mean values+s.d. for each group. Data are pooled from three independent experiments for the 16-week time-point and from one experiment for the 0 and 4 week analyses. (b) Relative frequencies of LSK cells (Sca1+ cKithi), CMP (Sca1− cKithi FcgRlo CD34+) and GMP (Sca1− cKithi FcgR+ CD34+) cells among lineage− (lin−; Ter119−, CD3e−, Gr1− and B220−) and CD127− BM cells isolated from 16-week-HFCD-fed or chow-fed mice. Bars show mean values+s.d. of n=6-9 HFCD-fed mice (two independent experiments) and n=4–5 chow-fed controls. (c) Myeloid colony-forming units per well of 5 × 103 plated lin− BM cells and (d) relative frequencies of colony subtypes (M: monocyte colonies; G: granulocyte colonies; GM: mixed monocyte/granulocyte colonies). Data show mean values+s.d. of n=6–9 HFCD-fed mice (from two independent experiments) and from n=4–5 chow-fed mice per group. (e) Representative examples of CFU-G, CFU-M and CFU-GM. (f) mRNA expression of Irf8 and Cebpe in GMP isolated from 16-week-HFCD-fed mice. (g) Representative histograms for TREM-1 surface expression (lines) versus isotype control staining (filled) on peripheral blood neutrophils, Ly6Chi and Ly6Clo monocytes from Trem1+/+ Apoe−/− mice 16 weeks post chow or HFCD feeding. (h) Median fluorescence intensity (MFI) of TREM-1 surface expression (with subtracted MFI values of matched isotype control-stained cells) on peripheral blood myeloid cell subsets at the indicated time points post HFCD feeding in Trem1+/+ Apoe−/− (black symbols) and Trem1−/− Apoe−/− (open symbols) mice. Symbols indicate mean+s.d. of n=5 mice and data are representative of three independent experiments for Trem1+/+ Apoe−/− mice. (i) serum soluble TREM-1 was determined by ELISA. *P<0.05, **P<0.01, ***P<0.001 as determined by the two-way ANOVA test (two-tailed t-test for f). Statistically not significant differences with P>0.05 are not indicated.
