title: Increased primary amine oxidase expression and activity in white adipose tissue of obese and diabetic db-/- mice.
abstract: The major form of primary amine oxidase expressed in adipose tissue (AT) is encoded by AOC3 gene and is known as semicarbazide-sensitive amine oxidase, identical to vascular adhesion protein-1 (SSAO/VAP-1). Exogenous substrates of SSAO/VAP-1 (e.g. benzylamine) stimulate glucose transport in adipocytes and improve glucose tolerance when injected in diabetic rodents. Numerous reports on the circulating, soluble SSAO/VAP-1 have univocally evidenced an increase in diabetic conditions. However, only scarce studies have investigated whether obesity and/or diabetes is accompanied with variations of AOC3 expression in AT. Therefore, we compared the SSAO/VAP-1 content in different fat depots of db-/- mice (lacking leptin receptor and being hyperphagic, diabetic and obese) and db+/- littermates (normoglycemic and lean). AOC3 expression was increased in perigonadal and subcutaneous AT of db-/- mice, while the maximal velocity of benzylamine oxidation (V (max), expressed as pmoles of hydrogen peroxide produced/min/mg protein) increased only in the latter. Indeed, the relative abundance of primary amine oxidase was increased in subcutaneous AT of db-/- mice at all the levels: mRNA, protein and activity. While considering the overall capacity to oxidise amines contained in each depot, there was an increase in the hypertrophic fat pads of the obese db-/- mice, irrespective of their anatomical location, as a result of their dramatically larger mass than in lean db+/- control. Such higher amount of AT-bound primary amine oxidase warrants further studies to determine whether SSAO/VAP-1 inhibition or activation may be useful in treating metabolic diseases.
authors.affiliation: Université de Toulouse, UPS, Institut de Médecine Moléculaire de Rangueil (I2MC), Toulouse, France.
authors.forename: Zsuzsa
authors.initials: Z
authors.lastname: Iffiú-Soltész
authors.forename: Josep
authors.initials: J
authors.lastname: Mercader
authors.forename: Danielle
authors.initials: D
authors.lastname: Daviaud
authors.forename: Jérémie
authors.initials: J
authors.lastname: Boucher
authors.forename: Christian
authors.initials: C
authors.lastname: Carpéné
mesh_terms: D052436:Adipose Tissue, White / Q000201:enzymology*; D006631:Amine Oxidase (Copper-Containing) / Q000096:biosynthesis* / Q000235:genetics; D000818:Animals; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics; D048909:Diabetes Complications / Q000201:enzymology* / Q000235:genetics; D004789:Enzyme Activation / Q000235:genetics; D005260:Female; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D008820:Mice, Obese; D009765:Obesity / Q000201:enzymology* / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics
chemical_list: D015815:Cell Adhesion Molecules; D006631:Amine Oxidase (Copper-Containing); C492678:semicarbazide-sensitive amine oxidase-vascular adhesion protein-1, mouse