title: Eicosapentaenoic acid and rosiglitazone increase adiponectin in an additive and PPARγ-dependent manner in human adipocytes.
abstract: Adiponectin, an anti-inflammatory and insulin-sensitizing protein secreted from adipose tissue, may be modulated by dietary fatty acids, although the mechanism is not fully known. Our objective was to investigate the effect of long-chain n-3 polyunsaturated fatty acids (PUFAs) on adiponectin in cultured human adipocytes, and to elucidate the role of peroxisome proliferator-activated receptor-γ (PPARγ) in this regulation. Isolated human adipocytes were cultured for 48 h with 100 µmol/l eicosapentaenoic acid (C20:5n-3, EPA), docosahexaenoic acid (C22:6n-3, DHA), palmitic acid (C16:0), 100 µmol/l EPA plus 100 µmol/l DHA, or bovine serum albumin (control). Additionally, adipocytes were treated for 48 h with a PPARγ antagonist (BADGE) or agonist (rosiglitazone) in isolation or in conjunction with either EPA or DHA. At 48 h, EPA and DHA increased (P < 0.05) adiponectin secretion by 88 and 47%, respectively, while EPA, but not DHA, also increased (136%, P < 0.001) cellular adiponectin protein. Interestingly, PPARγ antagonism completely abolished the DHA-mediated increase in secreted adiponectin, but only partially attenuated the EPA-mediated response. Thus, EPA's effects on adiponectin do not appear to be entirely PPARγ mediated. Rosiglitazone increased (P < 0.001) the secreted and cellular adiponectin protein (90 and 582%, respectively). Finally, the effects of EPA and rosiglitazone on adiponectin secretion were additive (+230% at 48 h combined, compared to 121 and 124% by EPA or rosiglitazone alone, respectively). Overall, our findings emphasize the therapeutic importance of long-chain n-3 PUFA alone, or in combination with a PPARγ agonist, as a stimulator of adiponectin, a key adipokine involved in obesity and related diseases.
authors.affiliation: Department of Human Health and Nutritional Sciences, Animal Science and Nutrition Building, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Justine M
authors.initials: JM
authors.lastname: Tishinsky
authors.forename: David W L
authors.initials: DW
authors.lastname: Ma
authors.forename: Lindsay E
authors.initials: LE
authors.lastname: Robinson
mesh_terms: D017667:Adipocytes / Q000378:metabolism; D052242:Adiponectin / Q000378:metabolism*; D002478:Cells, Cultured; D004281:Docosahexaenoic Acids / Q000494:pharmacology; D015118:Eicosapentaenoic Acid / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D047495:PPAR gamma / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000494:pharmacology*
chemical_list: D052242:Adiponectin; D007004:Hypoglycemic Agents; D047495:PPAR gamma; D045162:Thiazolidinediones; D000077154:Rosiglitazone; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid