All-Trans Retinoic Acid Enhances Bacterial Flagellin-Stimulated Proinflammatory Responses in Human Monocyte THP-1 Cells by Upregulating CD14

Figure 1

ATRA enhances NF-κB/AP-1 activity in THP-1 cells upon flagellin challenge. THP1-XBlue cells were treated with 1 μM ATRA or DMSO for 24 h (a), 48 h (b), and 72 h (c) and then stimulated with flagellin from S. typhimurium (a–c) or Bacillus subtilis (d) at various concentrations as indicated above for 24 h. Secreted alkaline phosphatase in cell culture supernatants was measured by ELISA to determine NF-κB/AP-1 activity. Bar graphs indicate relative NF-κB/AP-1 activity ± SD. Statistical significance was assessed by Student’s t test using SPSS. vs. DMSO-treated groups.

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