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Aim To explore the anti-inflammatory effect of taurolithocholic acid (TLCA) through network pharmacology-based analyses, to verify with in vitro macrophage study and to reveal the possible mechanisms. Methods The potential targets of TLCA were acquired from public database, and then the protein-protein interaction (PPI) networks against inflammation were constructed and visualized by using Cytoscape. Gene ontology (GO) analyses and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were performed. The binding activity of TLCA and its target (TGR5) was evaluated through molecular docking analysis. Lastly, the results of the network analysis were confirmed by lipopolysaccharide and interferon-γ induced RAW264.7 cells. Results There were 87 anti-inflammatory potential targets were screened. GO analysis revealed gene functions were mainly involved in regulation of inflammatory response, membrane raft and protein tyrosine kinase. The results of KEGG pathway analysis suggested that PI3K-Akt signaling pathway, human cytomegalovirus infection might be the critical pathways of TLCA against inflammation. The results of in vitro experiments showed that TLCA decreased the LPS and IFN-γ induced inflammatory response in RAW 264.7 macrophages. Furthermore, the expression of TGR5 protein increased after TLCA treatment. Conclusions The potential therapeutic targets of TLCA against inflammation are revealed through network pharmacology analysis. Our results indicate that TLCA might regulate key inflammatory markers through the membrane receptor TGR5.
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OBJECTIVE@#To explore the effects of taurolithocholic acid (tLCA) and chenodeoxycholic acid (CDCA) on the expression of aorexigenic neuropeptide in mouse hypothalamus GT1-7 cells.@*METHODS@#Mouse hypothalamic GT1-7 cells were treated with culture medium containing 10% FBS (control group, =3) or with 10 nmol/L, 100 nmol/L, 1 μmol/L and 10 μmol/L tLCA (tLCA group, =3) or CDCA (CDCA group, =3) for 12, 24 or 48 h. Real-time PCR was performed to determine the expression levels of proopiomelanocortin (POMC) mRNA in the cells, and the production levels of α-melanocyte-stimulating hormone (α-MSH) were assessed using an ELISA kit. Signal transduction and activator of transcription 3 phosphorylation (p-STAT3), threonine kinase phosphorylation (p-AKT), suppressor of cytokine signaling 3 (SOCS3), G protein-coupled bile acid receptor-1 (TGR5) and farnesoid X receptor (FXR) protein were detected by Western blotting.@*RESULTS@#Western blotting results showed that mouse hypothalamic GT1-7 cells expressed two bile acid receptors, TGR5 and FXR, whose expressions were regulated by bile acids. Real-time PCR showed that the expression of POMC mRNA was significantly increased in the cells after treatment with 10 μmol/L tLCA or CDCA for 24 h. POMC-derived anorexigenic peptide α-MSH increased significantly in GT1-7 cells after treatment with 10 μmol/L tLCA or CDCA for 24 h. Treatment of the cells with tLCA or CDCA significantly increased the expressions of intracellular signaling proteins including p-STAT3, p-AKT and SOCS3.@*CONCLUSIONS@#Mouse hypothalamic GT1-7 cells express bile acid receptors TGR5 and FXR. Bile acids tLCA or CDCA can promote the expression of POMC mRNA and increase the production of the anorexigenic peptide α-MSH. The intracellular signaling proteins p-AKT, p-STAT3 and SOCS3 are likely involved in bile acid-induced anorexigenic peptide production.