| First Author | Wunderling K | Year | 2021 |
| Journal | Mol Metab | Volume | 45 |
| Pages | 101150 | PubMed ID | 33359403 |
| Mgi Jnum | J:331125 | Mgi Id | MGI:6714638 |
| Doi | 10.1016/j.molmet.2020.101150 | Citation | Wunderling K, et al. (2021) Hepatic synthesis of triacylglycerols containing medium-chain fatty acids is dominated by diacylglycerol acyltransferase 1 and efficiently inhibited by etomoxir. Mol Metab 45:101150 |
| abstractText | OBJECTIVE: Medium-chain fatty acids (MCFAs) play an increasing role in human nutrition. In the liver, one fraction is used for synthesis of MCFA-containing triacylglycerol (MCFA-TG), and the rest is used for oxidative energy production or ketogenesis. We investigated which enzymes catalyse the synthesis of MCFA-TG and how inhibition of MCFA-TG synthesis or fatty acid (FA) oxidation influences the metabolic fate of the MCFAs. METHODS: FA metabolism was followed by time-resolved tracing of alkyne-labelled FAs in freshly isolated mouse hepatocytes. Quantitative data were obtained by mass spectrometry of several hundred labelled lipid species. Wild-type hepatocytes and cells from diacylglycerol acyltransferase (DGAT)1(-/-) mice were treated with inhibitors against DGAT1, DGAT2, or FA beta-oxidation. RESULTS: Inhibition or deletion of DGAT1 resulted in a reduction of MCFA-TG synthesis by 70%, while long-chain (LC)FA-TG synthesis was reduced by 20%. In contrast, DGAT2 inhibition increased MCFA-TG formation by 50%, while LCFA-TG synthesis was reduced by 5-25%. Inhibition of beta-oxidation by the specific inhibitor teglicar strongly increased MCFA-TG synthesis. In contrast, the widely used beta-oxidation inhibitor etomoxir blocked MCFA-TG synthesis, phenocopying DGAT1 inhibition. CONCLUSIONS: DGAT1 is the major enzyme for hepatic MCFA-TG synthesis. Its loss can only partially be compensated by DGAT2. Specific inhibition of beta-oxidation leads to a compensatory increase in MCFA-TG synthesis, whereas etomoxir blocks both beta-oxidation and MCFA-TG synthesis, indicating a strong off-target effect on DGAT1. |
