Tryptophan-sensing receptor GPR142 expression levels are directly regulated by proinflammatory cytokines in ghrelin-producing cells.

GPR142 is a tryptophan-sensing receptor that has been implicated in the regulation of inflammation. In this study, we investigated the relationships between inflammatory cytokine and GPR142 expression by using cellular, animal models, and human stomach samples. We found that addition of TNF-α, IL-6, and IL-1β into the culture of ghrelin-producing cell line, MGN3-1 cells, increased GPR142 mRNA expression levels. Lipopolysaccharide (LPS) injection to mice significantly increased GPR142 expression in the stomach, confirming the results observed in the cellular model. GPR142 mRNA expression levels in the stomach samples of morbidly obese patients were positively correlated with TNF-α, IL-6, and IL-1β mRNA levels. Taken together our results suggest that GPR142 expression is under the direct control of proinflammatory cytokines and support further investigation of GPR142 potential roles in inflammation.