Cadmium perturbed lipid profile and induced liver dysfunction in mice through phosphatidylcholine remodeling and promoting arachidonic acid synthesis and metabolism

Cadmium ion (Cd2+) exposure has been reported to associate with the prevalence of dyslipidemia, and contribute to the initiation and progression of nonalcoholic fatty liver disease (NAFLD). However, Cd2+ exposure perturbed specific metabolic pathways and underlying mechanisms are still unclear. In the present study, through lipidomics analyses of differential metabolites in serum between the Cd2+-exposed mice and the control group, 179 differential metabolites were identified, among which phosphatidylcholines (PCs) accounted for 49 % metabolites. Moreover, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment assay indicates that PCs participate in the metabolic pathways, including the Arachidonic Acid (AA) metabolism, which also could be potential NAFLD biomarkers. Moreover, in vivo and in vitro results suggested that Cd2+ exposure induced PC synthesis and remodeling, and increased AA level by promoting fatty acid desaturase 1 (FADS1) to catalyze synthesis process instead of cytosolic phospholipase A2 (cPLA2) mediated release pathway. Inhibition of FADS1 by T3364366 could reverse Cd-induced AA, prostaglandin E2 (PGE2) and triglyceride (TAG) levels, and it also reduce cisplatin resistance in HepG2 cells. This study provides new evidence of Cd2+-induced dyslipidemia and reveals underlying molecular mechanism involved in liver dysfunction of Cd2+ exposure.