Carnitine O-octanoyltransferase (CROT) deficiency in mice leads to an increase of omega-3 fatty acids

Carnitine O-octanoyltransferase (CROT) is a well-established peroxisomal enzyme involved in liver fatty acid oxidation, but less is known about its recently discovered role in promoting vascular calcification, and whether CROT-dependent liver metabolism contributes to the latter. To date, CROT function in the context of calcification potential has been conducted in the dyslipidemic low-density lipoprotein receptor-deficient ( ) mice. To differentiate peroxisome and CROT-dependent lipid biology from that of lipoprotein-mediated lipid biology, we therefore conducted a metabolomic analysis of the liver and plasma of normolipidemic CROT-deficient ( ) mice. We performed LC-MS-based metabolomics on liver and plasma derived from and +/- mice and sibling mice, using a dual-phase metabolite extraction protocol, and multiple LC-MS acquisition strategies. We identified between 79 to 453 annotated metabolites from annotated metabolites from liver samples, and 117 to 424 annotated metabolites from plasma samples. Through differential abundance analysis, we determined that omega-3 fatty acids such as EPA, DPA, and DHA were higher in the liver of and +/- mice than mice. EPA were higher in plasma of mice than mice. We also determined that the anti-inflammatory dicarboxylic acids, tetradecanedioic acid and azelaic acid, were higher in the plasma of CROT-deficient mice. Our study associated genetic CROT deletion with increased levels of anti-inflammatory molecules in mouse liver and plasma. These results suggest a potential mechanism for anti-calcification effects of CROT suppression and the potential use of omega-3 fatty acids as biomarkers for future CROT inhibition therapies.