Integrated plasma and liver gas chromatography mass spectrometry and liquid chromatography mass spectrometry metabolomics to reveal physiological functions of sodium taurocholate cotransporting polypeptide (NTCP) with an Ntcp knockout mouse model.

Sodium taurocholate cotransporting polypeptide (NTCP) is an important hepatocyte transporter, while its physiological functions require further investigation. In our study, an integrated plasma and liver GC-MS- and LC-MS-based metabolomics strategy with an optimized two-step liquid-liquid extraction was utilized to explore the physiological functions of NTCP via a knockout (KO) mouse model. The present study found that NTCP deficiency resulted in obvious metabolic change in the plasma and liver of mice. Totally, 102 and 87 differential metabolites were discovered in the liver and plasma, respectively. Pathway analysis revealed that the metabolism of tyrosine, glycine, taurine, fatty acid and glycerophospholipid as well as the biosynthesis of tryptophan, pantothenate and CoA were significantly dysregulated in the Ntcp KO mice, indicating that NTCP is closely involved in these metabolic pathways. Moreover, L-tryptophan, cadaverine and D-pantothenic acid could serve as the diagnostic biomarker for NTCP deficiency. Our study provided deep insights into the physiological functions of NTCP, and the findings would hold the great potential to be used for the discovery of new therapeutic and diagnostic strategies for NTCP deficiency clinically.