Hormone-sensitive lipase is critical mediators of acute exercise-induced regulation of lipolysis in rat adipocytes Junetsu Ogasawara a,b,⇑ , Sachiko Nomura b , Nazibur Rahman b , Takuya Sakurai a , Takako Kizaki a , Tetsuya Izawa b,c , Hitoshi Ishida d , Shukoh Haga e , Hideki Ohno a a Department of Molecular Predictive Medicine and Sport Science, Kyorin University, School of Medicine, Mitaka, Tokyo 181-8611, Japan b Department of Kinesiology, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan c Department of Sports Biochemistry, Faculty of Health and Sports Science, Doshisha University, Kyotanabe, Kyoto 610-0394, Japan d Third Department of Internal Medicine, Kyorin University, School of Medicine, Mitaka, Tokyo 181-8611, Japan e Faculty of Liberal Arts, Nihonbashigakkan University, Kashiwa, Chiba 277-0005, Japan article info Article history: Received 27 July 2010 Available online 12 August 2010 Keywords: Acute exercise Lipolysis Exercise HSL Perilipin A CGI-58 abstract The purpose of the present study was to investigate the effect of acute exercise on lipolysis via coordina- tion of hormone-sensitive lipase (HSL) and scaffold proteins, i.e., perilipin A and comparative gene iden- tification-58 (CGI-58), in rat primary adipocytes. Glycerol release was significantly elevated immediately (0 h) and three hours (3 h) after exercise. Both activity and localization to the pellet of HSL were signif- icantly greater in the pellet fraction, which is included in lipid droplet associated-proteins, than in the supernatant fraction. In the pellet fraction, although neither perilipin A nor CGI-58 protein level changed, level of perilipin A/CGI-58 complex was significantly reduced, accompanied by up-regulated association of perilipin A/HSL at 0 h and 3 h after exercise. On the other hand, there were no changes in these mol- ecules at 24 h after exercise, despite a significant decrease in lipolysis that was observed in response to isoproterenol. These findings suggest that acute exercise enhances lipolysis up to at least 3 h after exer- cise in a manner dependent on modification of HSL and its association with and alteration in scaffold protein. Ó 2010 Elsevier Inc. All rights reserved. 1. Introduction Physical exercise has been shown to increase plasma catechol- amine levels, which in turn, stimulates hydrolysis of lipid droplets in adipocytes to release free fatty acids and glycerol that provide fuel for metabolism. It has been widely accepted that activation of cAMP-dependent protein kinase A (PKA) due to accumulation of intracellular cAMP is the major signaling mechanism by which hormonal stimulation of lipolysis takes place in adipocytes via b 1 -, b 2 -, and b 3 -adrenergic receptor (AR)-mediated signal transduc- tion, which is referred to as the lipolytic cascade [1]. Furthermore, there is growing evidence that both perilipin A and comparative gene identification-58 (CGI-58) protein act as scaffold proteins on lipid droplets in adipocytes. It has been reported that CGI-58 rap- idly disperses into the cytoplasm after stimulation of isoproterenol, a selective b 1 -, b 2 -, and b 3 -AR agonist [2], in order to facilitate ac- cess of HSL to lipid droplets following activation of PKA, although it binds to perilipin A on lipid droplets under basal conditions [3]. In addition, a study of perilipin A null mice has also demon- strated that hormonal stimulation of lipolysis is significantly less in adipocytes [4], suggesting that dynamic changes in scaffold function of both perilipin A and CGI-58 proteins play important roles in powerful lipolytic machinery in adipocytes. We have previously demonstrated that intracellular cAMP pro- duction in rat epididymal adipocytes is significantly increased immediately (0 h) and at three hours (3 h), but is significantly re- duced at 24 h after acute exercise in response to agonist [5]. More- over, our previous findings have shown that expression of the number of cell-surface b 2 -AR is closely associated with changes in intracellular cAMP levels [6], suggesting that acute exercise is capable of regulating physiological and biochemical changes in the lipolytic cascade in adipocytes after exercise. Indeed, it has been shown that cAMP-PKA-mediated phosphorylation of HSL at both Ser 563 and 660 in adipose tissue is modified by the acute exercise [7], and that transient hormonal stimulation of adipocytes leads to alteration in the localization of HSL from cytosol to lipid droplet [8] with quantitative shift of the HSL in PKA-dependent manner [9,10]. To date, however, there is no direct evidence to sup- port the effect of acute exercise on lipolysis in primary adipocytes via change in interaction of HSL with scaffold proteins following trafficking event of HSL. 0006-291X/$ - see front matter Ó 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.bbrc.2010.08.026 ⇑ Corresponding author at: Department of Molecular Predictive Medicine and Sport Science, Kyorin University, School of Medicine, 6-20-2, Shinkawa, Mitaka, Tokyo 181-8611, Japan. Fax: +81 422 44 4422. E-mail address: junetsu@ks.kyorin-u.ac.jp (J. Ogasawara). Biochemical and Biophysical Research Communications 400 (2010) 134–139 Contents lists available at ScienceDirect Biochemical and Biophysical Research Communications journal homepage: www.elsevier.com/locate/ybbrc