Journal
JOURNAL OF LIPID RESEARCH
Volume 63, Issue 4, Pages -Publisher
ELSEVIER
DOI: 10.1016/j.jlr.2022.100188
Keywords
click; lipid tracer; beta-oxidation; mid-chain fatty acid; CPT; fatty acid metabolism; lipid oxidation; lipidomics; mitochondria; peroxisomes
Categories
Funding
- Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) [KU 2374/3-1]
- Germany's Excellence Strategy [EXC2151 - 390873048]
Ask authors/readers for more resources
In this study, new tracers were introduced to study fatty acid beta-oxidation and metabolic intermediates. The findings revealed differences in metabolic handling of fatty acids of different chain length and identified a salvage pathway when mitochondrial beta-oxidation was hindered.
Fatty acid beta-oxidation is a key process in mammalian lipid catabolism. Disturbance of this process results in severe clinical symptoms, including dysfunction of the liver, a major beta-oxidizing tissue. For a thorough understanding of this process, a comprehensive analysis of involved fatty acid and acyl-carnitine intermediates is desired, but capable methods are lacking. Here, we introduce oxaalkyne and alkyne fatty acids as novel tracers to study the beta-oxidation of long- and medium-chain fatty acids in liver lysates and primary hepatocytes. Combining these new tracer tools with highly sensitive chromatography and mass spectrometry analyses, this study confirms differences in metabolic handling of fatty acids of different chain length. Unlike longer chains, we found that medium-chain fatty acids that were activated inside or outside of mitochondria by different acyl-CoA synthetases could enter mitochondria in the form of free fatty acids or as carnitine esters. Upon mitochondrial beta-oxidation, shortened acyl-carnitine metabolites were then produced and released from mitochondria. In addition, we show that hepatocytes ultimately also secreted these shortened acyl chains into their surroundings. Furthermore, when mitochondrial beta-oxidation was hindered, we show that peroxisomal beta-oxidation likely acts as a salvage pathway, thereby maintaining the levels of shortened fatty acid secretion. Taken together, we conclude that this new method based on oxaalkyne and alkyne fatty acids allows for metabolic tracing of the beta-oxidation pathway in tissue lysate and in living cells with unique coverage of metabolic intermediates and at unprecedented detail.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available