Adipo‐specific chemerin knockout alters the metabolomic profile of adipose tissue under normal and high‐fat diet conditions: Application of an untargeted liquid chromatography–tandem mass spectrometry metabolomics method

To explore the metabolic effect of chemerin, adipose-specific chemerin knockout (adipo-chemerin-/- ) male mice were established and fed with 5-week normal diet (ND) or high-fat diet (HFD), and then the glycolipid metabolism index was measured and epididymal adipose tissue metabolomics detected using untargeted LC-tandem mass spectrometry (LC-MS/MS). Under HFD, adipo-chemerin-/- mice showed improved glycolipid metabolism (decreased total cholesterol, low-density lipoprotein-cholesterol, insulin and Homeostasis Model Assessment of Insulin Resistance) compared with flox (control) mice. Furthermore, orthogonal partial least squares-discriminant analysis score plots identified separation of metabolites between adipo-chemerin-/- mice and flox mice fed ND and HFD. Under HFD, 28 metabolites were significantly enhanced in adipo-chemerin-/- mice, and pathway enrichment analysis suggested strong relationship of the differential metabolites with arginine and proline metabolism, phenylalanine metabolism, and phenylalanine, tyrosine and tryptophan biosynthesis, which were directly or indirectly related to lipid metabolism, inflammation and oxidative stress. Under ND, taurine was increased in adipo-chemerin-/- mice, resulting in taurine and hypotaurine metabolism and primary bile acid biosynthesis. In conclusion, the improved effect of chemerin knockdown on the glycolipid metabolism of HFD-feeding male mice might be associated with the increases in differential metabolites and metabolic pathways involved in lipid metabolism, inflammation and oxidative stress, which provided insights into the mechanism of chemerin from a metabolomics aspect.