title: Genetically altered expression of spermidine/spermine N1-acetyltransferase affects fat metabolism in mice via acetyl-CoA.
abstract: The acetylating enzyme, spermidine/spermine N1-acetyltransferase, participates in polyamine homeostasis by regulating polyamine export and catabolism. Previously, we reported that overexpression of the enzyme in cultured tumor cells and mice activates metabolic flux through the polyamine pathway and depletes the N1-acetyltransferase coenzyme and fatty acid precursor, acetyl-CoA. Here, we investigate this possibility in spermidine/spermine N1-acetyltransferase transgenic mice in which the enzyme is systemically overexpressed and in spermidine/spermine N1-acetyltransferase knock-out mice. Tissues of the former were characterized by increased N1-acetyltransferase activity, a marked elevation in tissue and urinary acetylated polyamines, a compensatory increase in polyamine biosynthetic enzyme activity, and an increase in metabolic flux through the polyamine pathway. These polyamine effects were accompanied by a decrease in white adipose acetyl- and malonyl-CoA pools, a major (20-fold) increase in glucose and palmitate oxidation, and a distinctly lean phenotype. In SSAT-ko mice, the opposite relationship between polyamine and fat metabolism was observed. In the absence of N1-acetylation of polyamines, there was a shift in urinary and tissue polyamines indicative of a decline in metabolic flux. This was accompanied by an increase in white adipose acetyl- and malonyl-CoA pools, a decrease in adipose palmitate and glucose oxidation, and an accumulation of body fat. The latter was further exaggerated under a high fat diet, where knock-out mice gained twice as much weight as wild-type mice. A model is proposed whereby the expression status of spermidine/spermine N1-acetyltransferase alters body fat accumulation by metabolically modulating tissue acetyl- and malonyl-CoA levels, thereby influencing fatty acid biosynthesis and oxidation.
authors.affiliation: Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Jell
authors.forename: Salim
authors.initials: S
authors.lastname: Merali
authors.forename: Mary L
authors.initials: ML
authors.lastname: Hensen
authors.forename: Richard
authors.initials: R
authors.lastname: Mazurchuk
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Spernyak
authors.forename: Paula
authors.initials: P
authors.lastname: Diegelman
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Kisiel
authors.forename: Carlos
authors.initials: C
authors.lastname: Barrero
authors.forename: Kristin K
authors.initials: KK
authors.lastname: Deeb
authors.forename: Leena
authors.initials: L
authors.lastname: Alhonen
authors.forename: Mulchand S
authors.initials: MS
authors.lastname: Patel
authors.forename: Carl W
authors.initials: CW
authors.lastname: Porter
mesh_terms: D000105:Acetyl Coenzyme A / Q000378:metabolism*; D000123:Acetyltransferases / Q000235:genetics* / Q000502:physiology*; D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D020738:Leptin / Q000097:blood; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism; D010641:Phenotype; D011073:Polyamines / Q000378:metabolism; D000099228:Diamine N-Acetyltransferase
chemical_list: D000105:Acetyl Coenzyme A; D000123:Acetyltransferases; D005227:Fatty Acids; D005947:Glucose; D020738:Leptin; D010100:Oxygen; D011073:Polyamines; D000099228:Diamine N-Acetyltransferase