Effects of bioactive salmon peptides and fatty acids on cellular transport and secretion of adiponectin

Abstract

Plasma adiponectin levels are inversely related to several components of the metabolic syndrome and therapeutics that target adiponectin secretion are emerging. Consumption of fish oil is associated with improved metabolic profile, however, there is additional evidence that the protein component of fish may also have metabolic benefits. The aim of this study was to examine the effects of fish fatty acids and peptides on adiponectin assembly and secretion in differentiated 3T3‐L1 adipocytes. Treatment with polyunsaturated fatty acids (PUFAs) increased total cellular adiponectin levels but did not increase adiponectin secretion. In addition, two fractions of molecular weight fractionated (<1000 dalton) salmon peptides, but not cod peptides, stimulated adiponectin synthesis and secretion. Subcellular fractionation on sucrose density gradients revealed that the majority of cellular adiponectin is located in the endoplasmic reticulum (ER). Treatment of the cells with Brefeldin A prevented adiponectin secretion and caused cellular accumulation of the high molecular weight adiponectin oligomers. These data suggest that the ER is an important site of cellular adiponectin accumulation and that treatment with PUFAs or salmon peptides can increase adiponectin in this adipocyte model.Grant Funding Source: Heart and Stroke Foundation of Canada and Natural Sciences and Engineering Research Council of Canada