Okadaic Acid, a Bioactive Fatty Acid from Halichondria okadai, Stimulates Lipolysis in Rat Adipocytes: The Pivotal Role of Perilipin Translocation. (10th November 2013)

• Record Type: Journal Article
• Authors: Chang, Nen-Chung; Lin, Aming Chor-Ming; Hsu, Cheng-Chen; Liu, Jung-Sheng; Tsui, Leo; Chen, Chien-Yuan; Jayakumar, Thanasekaran; Fong, Tsorng-Harn
• Other Names: Sheu Joen-Rong Academic Editor.
• Is Part Of: Evidence-based complementary and alternative medicine. Volume 2013(2013)
• Publication Date: 2013-11-10
• Subjects: Alternative medicine -- Periodicals; 615.505
• DOI: 10.1155/2013/545739
• Languages: English
• ISSNs: 1741-427X

Abstract

Abstract : Lipid metabolism in visceral fat cells is correlated with metabolic syndrome and cardiovascular diseases. Okadaic-acid, a 38-carbon fatty acid isolated from the black sponge Halichondria okadai, can stimulate lipolysis by promoting the phosphorylation of several proteins in adipocytes. However, the mechanism of okadaic acid-induced lipolysis and the effects of okadaic acid on lipid-droplet-associated proteins (perilipins and beta-actin) remain unclear. We isolated adipocytes from rat epididymal fat pads and treated them with isoproterenol and/or okadaic acid to estimate lipolysis by measuring glycerol release. Incubating adipocytes with okadaic acid stimulated time-dependent lipolysis. Lipid-droplet-associated perilipins and beta-actin were analyzed by immunoblotting and immunofluorescence, and the association of perilipin A and B was found to be decreased in response to isoproterenol or okadaic acid treatment. Moreover, okadaic-acid treatment could enhance isoproterenol-mediated lipolysis, whereas treatment of several inhibitors such as KT-5720 (PKA inhibitor), calphostin C (PKC inhibitor), or KT-5823 (PKG inhibitor) did not attenuate okadaic-acid-induced lipolysis. By contrast, vanadyl acetylacetonate (tyrosine phosphatase inhibitor) blocked okadaic-acid-dependent lipolysis. These results suggest that okadaic acid induces the phosphorylation and detachment of lipid-droplet-associated perilipin A and B from the lipid droplet surface and thereby leads to accelerated lipolysis.