title: Mitochondrial 2,4-dienoyl-CoA reductase deficiency in mice results in severe hypoglycemia with stress intolerance and unimpaired ketogenesis.
abstract: The mitochondrial beta-oxidation system is one of the central metabolic pathways of energy metabolism in mammals. Enzyme defects in this pathway cause fatty acid oxidation disorders. To elucidate the role of 2,4-dienoyl-CoA reductase (DECR) as an auxiliary enzyme in the mitochondrial beta-oxidation of unsaturated fatty acids, we created a DECR-deficient mouse line. In Decr(-/-) mice, the mitochondrial beta-oxidation of unsaturated fatty acids with double bonds is expected to halt at the level of trans-2, cis/trans-4-dienoyl-CoA intermediates. In line with this expectation, fasted Decr(-/-) mice displayed increased serum acylcarnitines, especially decadienoylcarnitine, a product of the incomplete oxidation of linoleic acid (C(18:2)), urinary excretion of unsaturated dicarboxylic acids, and hepatic steatosis, wherein unsaturated fatty acids accumulate in liver triacylglycerols. Metabolically challenged Decr(-/-) mice turned on ketogenesis, but unexpectedly developed hypoglycemia. Induced expression of peroxisomal beta-oxidation and microsomal omega-oxidation enzymes reflect the increased lipid load, whereas reduced mRNA levels of PGC-1alpha and CREB, as well as enzymes in the gluconeogenetic pathway, can contribute to stress-induced hypoglycemia. Furthermore, the thermogenic response was perturbed, as demonstrated by intolerance to acute cold exposure. This study highlights the necessity of DECR and the breakdown of unsaturated fatty acids in the transition of intermediary metabolism from the fed to the fasted state.
authors: Department of Biochemistry and Biocenter Oulu, University of Oulu, Oulu, Finland.
authors: Ilkka J
authors: IJ
authors: Miinalainen
authors: Werner
authors: W
authors: Schmitz
authors: Anne
authors: A
authors: Huotari
authors: Kaija J
authors: KJ
authors: Autio
authors: Raija
authors: R
authors: Soininen
authors: Emiel
authors: E
authors: Ver Loren van Themaat
authors: Myriam
authors: M
authors: Baes
authors: Karl-Heinz
authors: KH
authors: Herzig
authors: Ernst
authors: E
authors: Conzelmann
authors: J Kalervo
authors: JK
authors: Hiltunen
mesh_terms: D000818:Animals; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D007003:Hypoglycemia / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology*; D007657:Ketone Bodies / Q000096:biosynthesis*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000172:deficiency* / Q000235:genetics; D013312:Stress, Physiological; D014280:Triglycerides / Q000378:metabolism
chemical_list: D005231:Fatty Acids, Unsaturated; D007657:Ketone Bodies; D014280:Triglycerides; D044925:Oxidoreductases Acting on CH-CH Group Donors; C100153:2,4-dienoyl-CoA reductase; D005947:Glucose