Inflammatory changes in adipose tissue enhance expression of GPR84, a medium‐chain fatty acid receptor

In this study we aimed to identify the physiological roles of G protein‐coupled receptor 84 (GPR84) in adipose tissue, together with medium‐chain fatty acids (MCFAs), the specific ligands for GPR84. In mice, high‐fat diet up‐regulated GPR84 expression in fat pads. In 3T3‐L1 adipocytes, co‐culture with a macrophage cell line, RAW264, or TNFα remarkably enhanced GPR84 expression. In the presence of TNFα, MCFAs down‐regulated adiponectin mRNA expression in 3T3‐L1 adipocytes. Taken together, our results suggest that GPR84 emerges in adipocytes in response to TNFα from infiltrating macrophages and exacerbates the vicious cycle between adiposity and diabesity.