Figure 4. TRAM deficiency gives rise to resolving monocytes with elevated expression of CD200R both in vitro and in vivo.
(A and B) Dimensionality reduction and clustering through uniform manifold approximation and projection (UMAP) of the scRNA-Seq data from WT (A) or TRAM monocytes (B) challenged with either PBS or 100 pg/mL LPS as we described in Methods. (C) Heatmaps showing representative genes differentially expressed in different clusters of monocytes challenged with subclinical-dose LPS. (D) Dot plot comparison of representative genes differentially expressed among LPS-treated WT versus Tram−/− monocytes. (E) BM cells from WT C57 BL/6 mice and Tram−/− mice were cultured with M-CSF (10 ng/mL) for 5 days. The surface expression of CD200R was analyzed and quantified by flow cytometry. (F) Apoe−/− Tram+/+ mice and Apoe−/− Tram−/− mice were fed with HFD for 8 weeks. Surface expression of CD200R on CD11b+Ly6C++ monocytes in the peripheral blood, BM, spleen, and aorta was examined by flow cytometry. Data are representative of 2 independent experiments, and error bars represent means ± SEM. *P < 0.05, and ***P < 0.001; Student’s 2-tailed t test (n = 3 to 10 for each group).
