Figure 1.

ATRA differentially modulates proinflammatory cytokine secretion of LPS-activated MΦs. MΦs were pre-incubated with ATRA (1 µM) where indicated, and then stimulated with LPS (100 ng/mL) for the indicated time. Cell culture supernatants were collected, and the secretion of (A) TNFα and IL-6 were measured by ELISA. (B) For IL-1β induction, cells were subsequently incubated with ATP (5 mM) for 45 min. (C) Cells were pre-treated with increasing concentrations of ATRA as indicated, and IL-β secretion was measured 6 h following treatment. (D) Cells were pretreated with MCC950 (1 µM) 1 h before ATP treatment. C, control (6 h mock-treated cells). Data were obtained from at least four healthy donors. All results are shown as means ± SEM. (* p < 0.05, ** p < 0.01, *** p < 0.001). +, −, presence or absence of indicated substance, respectively