title: Lack of phosphatidylethanolamine N-methyltransferase in mice does not promote fatty acid oxidation in skeletal muscle.
abstract: Phosphatidylethanolamine N-methyltransferase (PEMT) converts phosphatidylethanolamine (PE) to phosphatidylcholine (PC) in the liver. Mice lacking PEMT are protected from high-fat diet-induced obesity and insulin resistance, and exhibit increased whole-body energy expenditure and oxygen consumption. Since skeletal muscle is a major site of fatty acid oxidation and energy utilization, we determined if rates of fatty acid oxidation/oxygen consumption in muscle are higher in Pemt(-/-) mice than in Pemt(+/+) mice. Although PEMT is abundant in the liver, PEMT protein and activity were undetectable in four types of skeletal muscle. Moreover, amounts of PC and PE in the skeletal muscle were not altered by PEMT deficiency. Thus, we concluded that any influence of PEMT deficiency on skeletal muscle would be an indirect consequence of lack of PEMT in liver. Neither the in vivo rate of fatty acid uptake by muscle nor the rate of fatty acid oxidation in muscle explants and cultured myocytes depended upon Pemt genotype. Nor did PEMT deficiency increase oxygen consumption or respiratory function in skeletal muscle mitochondria. Thus, the increased whole body oxygen consumption in Pemt(-/-) mice, and resistance of these mice to diet-induced weight gain, are not primarily due to increased capacity of skeletal muscle for utilization of fatty acids as an energy source.
authors.affiliation: Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Canada; Department of Medicine, University of Alberta, Edmonton, Canada.
authors.forename: Guergana
authors.initials: G
authors.lastname: Tasseva
authors.affiliation: Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Canada; Department of Biochemistry, University of Alberta, Edmonton, Canada.
authors.forename: Jelske N
authors.initials: JN
authors.lastname: van der Veen
authors.affiliation: Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Canada; Department of Biochemistry, University of Alberta, Edmonton, Canada.
authors.forename: Susanne
authors.initials: S
authors.lastname: Lingrell
authors.affiliation: Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Canada; Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada.
authors.forename: René L
authors.initials: RL
authors.lastname: Jacobs
authors.affiliation: Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Canada; Department of Biochemistry, University of Alberta, Edmonton, Canada.
authors.forename: Dennis E
authors.initials: DE
authors.lastname: Vance
authors.affiliation: Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Canada; Department of Medicine, University of Alberta, Edmonton, Canada. Electronic address: jean.vance@ualberta.ca.
authors.forename: Jean E
authors.initials: JE
authors.lastname: Vance
mesh_terms: D000818:Animals; D059305:Diet, High-Fat / Q000009:adverse effects; D004041:Dietary Fats / Q000009:adverse effects; D004734:Energy Metabolism; D005227:Fatty Acids / Q000378:metabolism*; D015870:Gene Expression; D007333:Insulin Resistance; D008099:Liver / Q000201:enzymology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008928:Mitochondria / Q000201:enzymology; D032342:Muscle Cells / Q000166:cytology / Q000201:enzymology; D018482:Muscle, Skeletal / Q000201:enzymology*; D009765:Obesity / Q000201:enzymology* / Q000209:etiology / Q000235:genetics; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D010713:Phosphatidylcholines / Q000378:metabolism*; D050918:Phosphatidylethanolamine N-Methyltransferase / Q000172:deficiency* / Q000235:genetics; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D061251:Primary Cell Culture
chemical_list: D004041:Dietary Fats; D005227:Fatty Acids; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; C483858:phosphatidylethanolamine; C559160:PEMT protein, mouse; D050918:Phosphatidylethanolamine N-Methyltransferase
keywords: Fatty acid oxidation; High-fat diet; Malonyl-CoA; Mitochondria; Myotubes; Phosphatidylcholine