15-Deoxy-Δ¹²,¹⁴-Prostaglandin J₂ Inhibits IFN-γ-Induced Galectin-9 Expression in Cultured Human Umbilical Vein Endothelial Cells

Background: Galectin-9 is involved in chemotaxis and adhesion of eosinophils, and is induced in vascular endothelial cells by interferon-γ (IFN-γ). 15-Deoxy-Δ¹²,¹⁴-prostaglandin J₂ (15d-PGJ₂) is a ligand for peroxisome proliferator-activated receptor-γ (PPAR-γ), and known to modulate the expression of various genes. Methods: We have studied the effect of 15d-PGJ₂ on the IFN-γ-induced galectin-9 expression in human umbilical vein endothelial cells (HUVEC) in culture. Results: 15d-PGJ₂ inhibited the IFN-γ-induced galectin-9 expression in a PPAR-γ-independent manner, and also inhibited the adhesion of EoL-1 cells to an HUVEC monolayer treated with IFN-γ. 15d-PGJ₂ partially inhibited IFN-γ-induced phosphorylation of STAT-1 in HUVEC. Conclusions: 15d-PGJ₂ may regulate inflammatory reactions through the inhibition of galectin-9 expression.