title: Annexin A6 regulates adipocyte lipid storage and adiponectin release.
abstract: Lipid storage and adipokine secretion are critical features of adipocytes. Annexin A6 (AnxA6) is a lipid-binding protein regulating secretory pathways and its role in adiponectin release was examined. The siRNA-mediated AnxA6 knock-down in 3T3-L1 preadipocytes impaired proliferation, and differentiation of AnxA6-depleted cells to mature adipocytes was associated with higher soluble adiponectin and increased triglyceride storage. The latter was partly attributed to reduced lipolysis. Accordingly, AnxA6 overexpression in 3T3-L1 adipocytes lowered cellular triglycerides and adiponectin secretion. Indeed, serum adiponectin was increased in AnxA6 deficient mice. Expression analysis identified AnxA6 protein to be more abundant in intra-abdominal compared to subcutaneous adipose tissues of mice and men. AnxA6 protein levels increased in white adipose tissues of obese mice and here, levels were highest in subcutaneous fat. AnxA6 protein in adipocytes was upregulated by oxidative stress which might trigger AnxA6 induction in adipose tissues and contribute to impaired fat storage and adiponectin release.
authors.affiliation: Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Krautbauer
authors.affiliation: Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany.
authors.forename: Elisabeth M
authors.initials: EM
authors.lastname: Haberl
authors.affiliation: Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany.
authors.forename: Kristina
authors.initials: K
authors.lastname: Eisinger
authors.affiliation: Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany.
authors.forename: Rebekka
authors.initials: R
authors.lastname: Pohl
authors.affiliation: Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Rein-Fischboeck
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain.
authors.forename: Carles
authors.initials: C
authors.lastname: Rentero
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Alvarez-Guaita
authors.affiliation: Departament de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Enrich
authors.affiliation: Faculty of Pharmacy, University of Sydney, Sydney, NSW, 2006, Australia.
authors.forename: Thomas
authors.initials: T
authors.lastname: Grewal
authors.affiliation: Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany. Electronic address: christa.buechler@klinik.uni-regensburg.de.
authors.forename: Christa
authors.initials: C
authors.lastname: Buechler
authors.affiliation: Department of Internal Medicine I, Regensburg University Hospital, 93042 Regensburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Neumeier
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D050156:Adipogenesis / Q000187:drug effects; D052242:Adiponectin / Q000378:metabolism*; D000818:Animals; D017317:Annexin A6 / Q000378:metabolism*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology; D018925:Chemokines / Q000097:blood; D005227:Fatty Acids / Q000494:pharmacology; D055785:Gene Knockdown Techniques; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood; D050152:Intra-Abdominal Fat / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D066292:Lipid Droplets / Q000187:drug effects / Q000378:metabolism; D050356:Lipid Metabolism / Q000187:drug effects; D008066:Lipolysis / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009765:Obesity / Q000378:metabolism / Q000473:pathology; D010087:Oxides / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D014280:Triglycerides / Q000378:metabolism
chemical_list: D052242:Adiponectin; D017317:Annexin A6; D001152:Arsenicals; D018925:Chemokines; D005227:Fatty Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D007004:Hypoglycemic Agents; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; D010087:Oxides; D014280:Triglycerides; C523686:chemerin protein, mouse; D000077237:Arsenic Trioxide
keywords: Adipokine; Intra-abdominal fat; Lipid droplet; Lipolysis; Obesity