CXCL4 and CXCL4L1 Differentially Affect Monocyte Survival and Dendritic Cell Differentiation and Phagocytosis
Fig 2
In contrast to CXCL4L1, CXCL4 induces morphological changes in monocyte-derived macrophages and promotes their survival.
CD14+ monocytes were cultured in the presence of M-CSF (30 ng/ml), natural CXCL4 (1 and 10 μg/ml), recombinant CXCL4L1 (1 and 10 μg/ml) (panel A-C) or a combination of CXCL4 (10 μg/ml) and CXCL4L1 (1 and 10 μg/ml) (panel D). Panel A reports bright field pictures illustrating the morphology of monocyte-derived macrophages after 6 days of culture (20x magnification; scale bar 10μm). Panel B: After 6 days of culture cells were stained with the viability dye Zombie Aqua before flow cytometry analysis. Dot plots (forward scatter versus fluorescence) from one representative experiment out of 8 are shown. The gate circles the living cells. Numbers indicate the % of viable cells in the sample. Panel C and D report quantification of monocyte-derived macrophages after 6 days of culture by the ATP lite assay. The obtained luminescence values were normalized relative to the luminescence value obtained after culture in the presence of M-CSF (dashed line). Results are shown as mean ± SEM from 6–9 independent experiments. ***p<0.001; Mann-Whitney U test (CXCL4 or CXCL4L1 versus M-CSF) - †††p<0.001; Mann-Whitney U test (CXCL4 versus CXCL4L1 at identical concentrations)—$p<0.05; Sign test [CXCL4 (10 μg/ml) versus the combination of CXCL4 (10 μg/ml) plus CXCL4L1 (10 μg/ml)].