GALM mRNA expression is increased by RA, but not by TNFα, in THP-1 monocytic cells. A, THP-1 cells were treated with control medium (n=6), retinoic acid (20 nM at time 0 and again after overnight incubation (24 h, n=5), TNFα (5 ng/ml, for 24 h, n=5), or RA overnight, followed by RA and TNFα for the final 24 h (n=6). The level of GALM mRNA was detected by microarray analysis of total RNA prepared from each well of cells. B, Time course of GALM mRNA expression in THP-1 cells. RA (20 nM) was applied at time 0 (n=6), and cells were analyzed after 2 h (n=2), 6 h (n=2), 16 h (n=3); after overnight incubation at 37°C, RA was added again (indicated by black triangles), up to 40 h (n=2). The mean ± SEM of the log(2) values of the array signal intensities are shown. Bars or points that do not share a superscript letter differed significantly (P values as shown).