25-Hydroxycholesterol-3-sulfate attenuates inflammatory response via PPAR signaling in human THP-1 macrophages

The nuclear receptor peroxisome proliferator-activated receptors (PPARs) are important in regulating lipid metabolism and inflammatory responses in macrophages. Activation of PPAR represses key inflam-matory response gene expressions. Recently, we identified a new choles-terol metabolite, 25-hydroxycholesterol-3-sulfate (25HC3S), as a potent regulatory molecule of lipid metabolism. In this paper, we report the effect of 25HC3S and its precursor 25-hydroxycholesterol (25HC) on PPAR activity and on inflammatory responses. Addition of 25HC3S to human macrophages markedly increased nuclear PPAR and cytosol IB and decreased nuclear NF-B protein levels. PPAR response element reporter gene assays showed that 25HC3S significantly increased lu-ciferase activities. PPAR competitor assay showed that the Ki for 25HC3S was 1 M, similar to those of other known natural ligands. NF-B-dependent promoter reporter gene assays showed that 25HC3S suppressed TNF-induced luciferase activities only when cotransfecte