Molecular cloning and characterization of farnesoid X receptor from large yellow croaker (Larimichthys crocea) and the effect of dietary CDCA on the expression of inflammatory genes in intestine and spleen

In the present study, farnesoid X receptor (FXR) was cloned and characterized from liver of large yellow croaker (L crocea) and the effects of dietary chenodeoxycholic acid (CDCA), a nature ligand of FXR, on the inflammatory genes expression in the intestine and spleen of large yellow croaker were investigated. Multiple alignments showed that FXR of large yellow croaker contained highly conserved DNA-binding domain and ligand binding domain compared with other species. The subcellular localization analysis showed that FXR-GFP fusion protein could target to the nucleus in HEK 293 t. The tissue specific results demonstrated that FXR was highly expressed in liver, intestine and kidney of large yellow croaker. In addition, dietary soybean oil decreased the expression of FXR and IL-10 and significantly increased the expression of the pro-inflammatory genes in the intestine or spleen, such as TNF alpha, COX-2, IL-1 beta, IL-6, while the supplementation of CDCA could partly reverse these effects. These results suggested that the supplementation of CDCA may relieve the inflammation of intestine and spleen in large yellow croaker via the activation of FXR.