ST2 suppresses IL-6 production via the inhibition of IκB degradation induced by the LPS signal in THP-1 cells

LPS induces the production of inflammatory cytokines via the stimulation of Toll-like receptors. In this study, we demonstrated that a Soluble secreted form of the ST2 gene product (M), I member of the interleukin-1 receptor Family, suppressed the production of IL-6 in an LPS-stimulated human monocytic leukemia cell line, THP-1. Immunofluorescence confocal microscopy revealed the binding of ST2 to the surface of the THP-1 cells, in which ST2 led to decreased binding of nuclear factor-kappa B to the IL-6 promoter. Furthermore, the degradation of 1KB in the cytoplasm after LPS stimulation was reduced by pretreatment with ST2. These results demonstrated that ST2 negatively regulates LPS-induced IL-6 production via the inhibition of 1KB degradation in THP-1 cells. (c) 2006 Elsevier Inc. All rights reserved.