The anti-inflammatory effect of the gut lactic acid bacteria-generated metabolite 10-oxo-cis-6,trans-11-octadecadienoic acid on monocytes

Abstract We evaluated the effect of gut bacterial metabolites of polyunsaturated fatty acids on inflammation and found that 10-oxo-cis-6,trans-11-octadecadienoic acid (γKetoC) strikingly suppressed LPS-induced IL-6 release from bone marrow-derived macrophages (BMMs), which was accompanied by reduced mRNA expression of Il6, TNF, and Il1b. γKetoC decreased the cAMP concentration in BMMs, suggesting that γKetoC stimulated G protein-coupled receptors. A Gq agonist significantly suppressed LPS-induced IL-6 expression in BMMs, whereas a Gi inhibitor partially abrogated γKetoC-mediated IL-6 suppression. Cytosolic Ca2+ was markedly increased by γKetoC, which was partly but not fully abrogated by an ion channel inhibitor. Taken together, these data suggest that γKetoC suppresses inflammatory cytokine expression in macrophages primarily through Gq and partially through Gi. γKetoC suppressed osteoclast development and IL-6 expression in synovial fibroblasts from rheumatoid arthritis (RA) patients, suggesting the beneficial effect of γKetoC on the prevention or treatment of RA.