Agonism of GPBAR1 on human monocytes reduces proinflammatory cytokine production and enhances cAMP.

<p>(A) Immune cell populations (CD3⁺ T cells, CD19⁺ B cells, CD56⁺ NK cells, Neutrophils and CD14⁺ monocytes) were enriched from blood and <i>Gpbar1</i> mRNA levels were assessed by microarray using Affymetrix chip technology. Absolute expression is normalized to relative expression of 62 control probes across the entire chip. CHO cells expressing human GPBAR1 were generated and stimulated with GPBAR1 agonists Lithocholic acid (B) or EX00000246 and BIX02694 (C) and cAMP production was assessed. The chemical structures of the molecules are shown in each case. Human monocytes (4 donors, assayed in triplicate) were isolated by negative selection and pre-treated with increasing concentrations of Lithocholic acid (LCA) or EX00000246 or BIX02694 at 1 µM for 30 minutes before stimulation with IFNγ + LPS and data is presented as percent of control (POC) (D–G) or pg/ml (H, I). Controls with no ligand were all treated with 0.1% DMSO in media. Supernatants were collected after 24 hours and assessed for IL-12p40 (D, F, H) and TNFα (E, G, I) by a sandwich immunoassay. Production of IL-12p40 (J) and TNFα (K) by LPS-stimulated monocytes was assessed in the presence of histamine and isoprenaline at 1 µM. Protein levels of IL-12p40 and TNFα were assessed after 24 hours.