The Impact of ATRA on Shaping Human Myeloid Cell Responses to Epithelial Cell-Derived Stimuli and on T-Lymphocyte Polarization

Figure 3

ATRA modifies the chemokine-dependent migration of in vitro differentiated myeloid cells. Caco2 cells were activated as described in Figure 1. The migratory potential of the monocyte-derived cells generated by GM-CSF+IL-4 or GM-CSF was tested in transwell chambers. cells were placed on the upper chamber and the Caco2 cell supernatants on the lower chamber of the transwell plate. After 24 hr, the number of cells, which migrated to the lower chamber in response to the Caco2 cell supernatants, was counted by flow cytometry. The migratory potential of cells generated in the presence of GM-CSF+IL-4 (a) or GM-CSF (b) is shown as compared to the migratory potential of CCL19 and CCL21 chemokines, used as positive controls. To determine the cause of high migration in response to IL-1β treated CEC supernatant, the GM-CSF+IL-4 (c) and GM-CSF (d) differentiated monocytes were treated with CXCL1, CXCL8, and CCL20 chemokines which were secreted exclusively by CEC on IL-1β treatment. Bar diagrams indicate mean ± SD of 3 independent experiments ,  , and  . Another fraction of monocyte-derived cells, differentiated by GM-CSF+IL-4 or GM-CSF, was also stimulated by the supernatant of IL-1β pretreated CEC in the presence or absence of ATRA. The cell surface expression of CCR7 in the differentiated monocyte derived cells was measured by flow cytometry (e). Red line depicts untreated monocyte-derived cells, green is for monocyte-derived cells treated by the supernatant of Caco2 cells previously activated by IL-1β, blue line is for monocyte-derived cells pretreated with the supernatant of Caco2 cells activated by IL-1β and ATRA, and brown line corresponds to cells treated by the supernatant of unstimulated Caco2 cells in combination with ATRA. Results of 3 independent experiments are shown as mean SD of MFI.

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