Transcription profiles of LPS-stimulated THP-1 monocytes and macrophages: a tool to study inflammation modulating effects of food-derived compounds.

An assay was developed to study inflammation-related immune responses of food compounds on monocytes and macrophages derived from THP-1 cell line. First strategy focused on the effects after stimulation with either lipopolysaccharide (LPS) or Concanavalin A (ConA). Gene expression kinetics of inflammation-related cytokines (IL-1β, IL-6, IL-8, IL-10 and TNF-α), inflammation-related enzymes (iNOS and COX-2), and transcription factors (NF-κB, AP-1 and SP-1) were analyzed using RT-PCR. Time dependent cytokine secretion was investigated to study the inflammation-related responses at protein level. LPS stimulation induced inflammation-related cytokine, COX-2 and NF-κB genes of THP-1 monocytes and THP-1 macrophages with the maximum up-regulation at 3 and 6 h, respectively. These time points, were subsequently selected to investigate inflammation modulating activity of three well known immuno-modulating food-derived compounds; quercetin, citrus pectin and barley glucan. Co-stimulation of LPS with either quercetin, citrus pectin, or barley glucan in THP-1 monocytes and macrophages showed different immuno-modulatory activity of these compounds. Therefore, we propose that simultaneously exposing THP-1 cells to LPS and food compounds, combined with gene expression response analysis are a promising in vitro screening tool to select, in a limited time frame, food compounds for inflammation modulating effects.