Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a novel biomarker of LDL clearance and a therapeutic target of cardiovascular disease. We examined the effects of aerobic exercise training in modulating PCSK9 abundance and hepatic sterol regulation in high-fat-fed C57BL/6 mice. Mice ( ) were assigned to a low-fat (LF), high-fat (HF), or an HF with exercise (HF？+？EX) group for 8 weeks. The HF？+？EX group was progressively trained 5 days/week on a motorized treadmill. The HF？+？EX group was protected against body weight (BW) gain and diet-induced dyslipidemia compared with the HF group. The HF？+？EX group demonstrated an increase in hepatic PCSK9 mRNA (1.9-fold of HF control, ) and a reduction in plasma PCSK9 (14%) compared with the HF group. Compared with HF mice, HF？+？EX mice demonstrated reduced hepatic cholesterol (14%) and increased ( ) nuclear SREBP2 protein (1.8-fold of HF group) and LDLr mRNA (1.4-fold of HF group). Plasma PCSK9 concentrations correlated positively with plasma non-HDL-C ( , ). Results suggest that treadmill exercise reduces non-HDL cholesterol and differentially modulates hepatic and blood PCSK9 abundance in HF-fed C57BL/6 mice. 1. Introduction Aerobic exercise is consistently associated with favorable shifts in blood triglycerides and HDL-C; however, data from intervention studies [1, 2] and numerous meta-analyses [3–6] also support a less well-characterized and variable LDL-C lowering response to exercise training. Beyond LDL-C lowering, lipoprotein-profiling studies also suggest that high-intensity exercise training may modulate LDL particle number and size distribution patterns [7, 8]. Using a kinetic tracer approach, Ficker et al. recently shed light on the potential mechanism of LDL-C lowering in response to exercise training. They reported increased fractional LDL clearance in both hypercholesterolemic and normolipidemic individuals following a 4-month exercise program consisting of stretching, cycling, and strength training exercises [9]. The degree of LDL-C lowering following exercise is likely dependent on multiple subject-specific factors (baseline lipid status, occurrence and extent of weight loss) and type and rigor of exercise training including schedule, frequency, and volume [3, 10]. Blood cholesterol concentrations are maintained within narrow range through complex and coordinated pathways that direct enterohepatic cholesterol absorption and synthesis, intravascular VLDL remodeling, and plasma LDL clearance through the LDL receptor (LDLr) by receptor-mediated endocytosis [11]. Transcriptional regulation of
References
[1]
T. Ronnemaa, J. Marniemi, P. Puukka, and T. Kuusi, “Effects of long-term physical exercise on serum lipids, lipoproteins and lipid metabolizing enzymes in type 2 (non-insulin-dependent) diabetic patients,” Diabetes Research, vol. 7, no. 2, pp. 79–84, 1988.
[2]
C. A. Slentz, J. A. Houmard, J. L. Johnson et al., “Inactivity, exercise training and detraining, and plasma lipoproteins. STRRIDE: a randomized, controlled study of exercise intensity and amount,” Journal of Applied Physiology, vol. 103, no. 2, pp. 432–442, 2007.
[3]
J. A. Halbert, C. A. Silagy, P. Finucane, R. T. Withers, and P. A. Hamdorf, “Exercise training and blood lipids in hyperlipidemic and normolipidemic adults: a meta-analysis of randomized, controlled trials,” European Journal of Clinical Nutrition, vol. 53, no. 7, pp. 514–522, 1999.
[4]
Z. V. Tran, A. Weltman, G. V. Glass, and D. P. Mood, “The effects of exercise on blood lipids and lipoproteins: a meta-analysis of studies,” Medicine and Science in Sports and Exercise, vol. 15, no. 5, pp. 393–402, 1983.
[5]
G. A. Kelley and K. S. Kelley, “Effects of aerobic exercise on lipids and lipoproteins in adults with type 2 diabetes: a meta-analysis of randomized-controlled trials,” Public Health, vol. 121, no. 9, pp. 643–655, 2007.
[6]
S. Koba, H. Tanaka, C. Maruyama et al., “Physical activity in the Japan population: association with blood lipid levels and effects in reducing cardiovascular and all-cause mortality,” Journal of Atherosclerosis and Thrombosis, vol. 18, no. 10, pp. 833–845, 2011.
[7]
W. E. Kraus, J. A. Houmard, B. D. Duscha et al., “Effects of the amount and intensity of exercise on plasma lipoproteins,” The New England Journal of Medicine, vol. 347, no. 19, pp. 1483–1492, 2002.
[8]
K. M. Huffman, V. H. Hawk, S. T. Henes et al., “Exercise effects on lipids in persons with varying dietary patterns-does diet matter if they exercise? Responses in studies of a targeted risk reduction intervention through defined exercise I,” The American Heart Journal, vol. 164, no. 1, pp. 117–124, 2012.
[9]
E. S. Ficker, R. C. Maranh？o, A. P. M. Chacra et al., “Exercise training accelerates the removal from plasma of LDL-like nanoemulsion in moderately hypercholesterolemic subjects,” Atherosclerosis, vol. 212, no. 1, pp. 230–236, 2010.
[10]
W. E. Kraus and C. A. Slentz, “Exercise training, lipid regulation, and insulin action: a tangled web of cause and effect,” Obesity, vol. 17, supplement 3, pp. S21–S26, 2009.
[11]
A. D. Marais, “Familial hypercholesterolaemia,” Clinical Biochemist Reviews, vol. 25, pp. 49–68, 2004.
[12]
M. S. Brown and J. L. Goldstein, “The SREBP pathway: regulation of cholesterol metabolism by proteolysis of a membrane-bound transcription factor,” Cell, vol. 89, no. 3, pp. 331–340, 1997.
[13]
N. G. Seidah and A. Prat, “The biology and therapeutic targeting of the proprotein convertases,” Nature Reviews Drug Discovery, vol. 11, no. 5, pp. 367–383, 2012.
[14]
M. Farnier, “The role of proprotein convertase subtilisin/kexin type 9 in hyperlipidemia: focus on therapeutic implications,” The American Journal of Cardiovascular Drugs, vol. 11, no. 3, pp. 145–152, 2011.
[15]
S. Poirier, G. Mayer, V. Poupon et al., “Dissection of the endogenous cellular pathways of PCSK9-induced low density Lipoprotein receptor degradation. Evidence for an intracellular route,” The Journal of Biological Chemistry, vol. 284, no. 42, pp. 28856–28864, 2009.
[16]
J. J. Hyun, H. Lee, K. Kim, Y. Kim, D. Yoon, and W. P. Sahng, “Sterol-dependent regulation of proprotein convertase subtilisin/kexin type 9 expression by sterol-regulatory element binding protein-2,” Journal of Lipid Research, vol. 49, no. 2, pp. 399–409, 2008.
[17]
M. C. G. J. Brouwers and M. M. J. van Greevenbroek, “Lipid Metabolism: the significance of plasma proprotein convertase subtilisin kexin type 9 in the elucidation of complex lipid disorders,” Current Opinion in Lipidology, vol. 22, no. 4, pp. 317–318, 2011.
[18]
C. Richard, P. Couture, S. Desroches et al., “Effect of the Mediterranean diet with and without weight loss on surrogate markers of cholesterol homeostasis in men with the metabolic syndrome,” The British Journal of Nutrition, vol. 107, no. 5, pp. 705–711, 2012.
[19]
S. C. Chong, M. A. Dollah, P. P. Chong, and A. Maha, “Phaleria macrocarpa (Scheff.) Boerl fruit aqueous extract enhances LDL receptor and PCSK9 expression in vivo and in vitro,” Journal of Ethnopharmacology, vol. 137, no. 1, pp. 817–827, 2011.
[20]
B. Cariou, C. Langhi, M. Le Bras et al., “Plasma PCSK9 concentrations during an oral fat load and after short term high-fat, high-fat high-protein and high-fructose diets,” Nutrition and Metabolism, vol. 10, no. 1, article 4, 2013.
[21]
F. Beppu, M. Hosokawa, Y. Niwano, and K. Miyashita, “Effects of dietary fucoxanthin on cholesterol metabolism in diabetic/obese KK-A(y) mice,” Lipids in Health and Disease, vol. 11, article 112, 2012.
[22]
E. A. Stein, D. Gipe, J. Bergeron et al., “Effect of a monoclonal antibody to PCSK9, REGN727/SAR236553, to reduce low-density lipoprotein cholesterol in patients with heterozygous familial hypercholesterolaemia on stable statin dose with or without ezetimibe therapy: a phase 2 randomised controlled trial,” The Lancet, vol. 380, no. 9836, pp. 29–36, 2012.
[23]
M. Frank-Kamenetsky, A. Grefhorst, N. N. Anderson et al., “Therapeutic RNAi targeting PCSK9 acutely lowers plasma cholesterol in rodents and LDL cholesterol in nonhuman primates,” Proceedings of the National Academy of Sciences of the United States of America, vol. 105, no. 33, pp. 11915–11920, 2008.
[24]
V. L. Billat, E. Mouisel, N. Roblot, and J. Melki, “Inter- and intrastrain variation in mouse critical running speed,” Journal of Applied Physiology, vol. 98, no. 4, pp. 1258–1263, 2005.
[25]
T. C. Rideout, S. V. Harding, and P. J. H. Jones, “Consumption of plant sterols reduces plasma and hepatic triglycerides and modulates the expression of lipid regulatory genes and de novo lipogenesis in C57BL/6J mice,” Molecular Nutrition and Food Research, vol. 54, supplement 1, pp. S7–S13, 2010.
[26]
S. V. Harding, T. C. Rideout, and P. J. H. Jones, “Hepatic nuclear sterol regulatory binding element protein 2 abundance is decreased and that of ABCG5 increased in male hamsters fed plant sterols,” Journal of Nutrition, vol. 140, no. 7, pp. 1249–1254, 2010.
[27]
D. L. Williamson, N. Kubica, S. R. Kimball, and L. S. Jefferson, “Exercise-induced alterations in extracellular signal-regulated kinase 1/2 and mammalian target of rapamycin (mTOR) signalling to regulatory mechanisms of mRNA translation in mouse muscle,” Journal of Physiology, vol. 573, no. 2, pp. 497–510, 2006.
[28]
S. Langheim, L. Yu, K. von Bergmann et al., “ABCG5 and ABCG8 require MDR2 for secretion of cholesterol into bile,” Journal of Lipid Research, vol. 46, no. 8, pp. 1732–1738, 2005.
[29]
T. C. Rideout, Z. Yuan, M. Bakovic et al., “Guar gum consumption increases hepatic nuclear SREBP2 and LDL receptor expression in pigs fed an atherogenic diet,” Journal of Nutrition, vol. 137, no. 3, pp. 568–572, 2007.
[30]
M. W. Pfaffl, “A new mathematical model for relative quantification in real-time RT-PCR,” Nucleic Acids Research, vol. 29, no. 9, article e45, 2001.
[31]
P. Costet, B. Cariou, G. Lambert et al., “Hepatic PCSK9 expression is regulated by nutritional status via insulin and sterol regulatory element-binding protein 1c,” The Journal of Biological Chemistry, vol. 281, no. 10, pp. 6211–6218, 2006.
[32]
E. P. Ratliff, A. Gutierrez, and R. A. Davis, “Transgenic expression of CYP7A1 in LDL receptor-deficient mice blocks diet-induced hypercholesterolemia,” Journal of Lipid Research, vol. 47, no. 7, pp. 1513–1520, 2006.
[33]
D. Feng, Y. Wang, Y. Mei et al., “Stearoyl-CoA desaturase 1 deficiency protects mice from immune-mediated liver injury,” Laboratory Investigation, vol. 89, no. 2, pp. 222–230, 2009.
[34]
M. Meissner, E. Lombardo, R. Havinga, U. J. F. Tietge, F. Kuipers, and A. K. Groen, “Voluntary wheel running increases bile acid as well as cholesterol excretion and decreases atherosclerosis in hypercholesterolemic mice,” Atherosclerosis, vol. 218, no. 2, pp. 323–329, 2011.
[35]
C. Napoli, S. Williams-Ignarro, F. de Nigris et al., “Long-term combined beneficial effects of physical training and metabolic treatment on atherosclerosis in hypercholesterolemic mice,” Proceedings of the National Academy of Sciences of the United States of America, vol. 101, no. 23, pp. 8797–8802, 2004.
[36]
C. Napoli, S. Williams-Ignarro, F. de Nigris et al., “Physical training and metabolic supplementation reduce spontaneous atherosclerotic plaque rupture and prolong survival in hypercholesterolemic mice,” Proceedings of the National Academy of Sciences of the United States of America, vol. 103, no. 27, pp. 10479–10484, 2006.
[37]
M. V. Heeren, L. E. de Sousa, C. Mostarda et al., “Exercise improves cardiovascular control in a model of dislipidemia and menopause,” Maturitas, vol. 62, no. 2, pp. 200–204, 2009.
[38]
F. Moien-Afshari, S. Ghosh, M. Khazaei, T. J. Kieffer, R. W. Brownsey, and I. Laher, “Exercise restores endothelial function independently of weight loss or hyperglycaemic status in db/db mice,” Diabetologia, vol. 51, no. 7, pp. 1327–1337, 2008.
[39]
C. Haskell-Luevano, J. W. Schaub, A. Andreasen et al., “Voluntary exercise prevents the obese and diabetic metabolic syndrome of the melanocortin-4 receptor knockout mouse,” FASEB Journal, vol. 23, no. 2, pp. 642–655, 2009.
[40]
F. F. Donatto, R. X. Neves, F. O. Rosa et al., “Resistance exercise modulates lipid plasma profile and cytokine content in the adipose tissue of tumour-bearing rats,” Cytokine, vol. 61, no. 2, pp. 426–432, 2013.
[41]
N. Pattyn, V. A. Cornelissen, S. R. Eshghi, and L. Vanhees, “The effect of exercise on the cardiovascular risk factors constituting the metabolic syndrome: a meta-analysis of controlled trials,” Sports Medicine, vol. 43, no. 2, pp. 121–133, 2013.
[42]
B. G. Teodoro, A. J. Natali, S. A. Fernandes et al., “Improvements of atherosclerosis and hepatic oxidative stress are independent of exercise intensity in LDLr(-/-) mice,” Journal of Atherosclerosis and Thrombosis, vol. 19, no. 10, pp. 904–911, 2012.
[43]
M. Meissner, N. Nijstad, F. Kuipers, and U. J. F. Tietge, “Voluntary exercise increases cholesterol efflux but not macrophage reverse cholesterol transport in vivo in mice,” Nutrition and Metabolism, vol. 7, article 54, 2010.
[44]
F. S. Lira, F. L. Tavares, A. S. Yamashita et al., “Effect of endurance training upon lipid metabolism in the liver of cachectic tumour-bearing rats,” Cell Biochemistry and Function, vol. 26, no. 6, pp. 701–708, 2008.
[45]
W. Yin, E. Carballo-Jane, D. G. McLaren et al., “Plasma lipid profiling across species for the identification of optimal animal models of human dyslipidemia,” Journal of Lipid Research, vol. 53, no. 1, pp. 51–65, 2012.
[46]
J. R. Turk and M. H. Laughlin, “Physical activity and atherosclerosis: Which animal model?” Canadian Journal of Applied Physiology, vol. 29, no. 5, pp. 657–683, 2004.
[47]
K. R. Wilund, L. A. Feeney, E. J. Tomayko, H. R. Chung, and K. Kim, “Endurance exercise training reduces gallstone development in mice,” Journal of Applied Physiology, vol. 104, no. 3, pp. 761–765, 2008.
[48]
C. Wei, M. Penumetcha, N. Santanam, Y. Liu, M. Garelnabi, and S. Parthasarathy, “Exercise might favor reverse cholesterol transport and lipoprotein clearance: potential mechanism for its anti-atherosclerotic effects,” Biochimica et Biophysica Acta, vol. 1723, no. 1–3, pp. 124–127, 2005.
[49]
D. J. Mahoney, A. Safdar, G. Parise et al., “Gene expression profiling in human skeletal muscle during recovery from eccentric exercise,” The American Journal of Physiology, vol. 294, no. 6, pp. R1901–R1910, 2008.
[50]
T. Kosenko, M. Golder, G. Leblond, W. Weng, and T. A. Lagace, “Low-density lipoprotein binds to proprotein convertase subtilisin/kexin type-9 (PCSK9) in human plasma and inhibits PCSK9-mediated LDL receptor degradation,” The Journal of Biological Chemistry, vol. 288, no. 12, pp. 8279–8288, 2013.
[51]
R. J. Schmidt, T. P. Beyer, W. R. Bensch et al., “Secreted proprotein convertase subtilisin/kexin type 9 reduces both hepatic and extrahepatic low-density lipoprotein receptors in vivo,” Biochemical and Biophysical Research Communications, vol. 370, no. 4, pp. 634–640, 2008.
[52]
A. Roubtsova, M. N. Munkonda, Z. Awan et al., “Circulating proprotein convertase subtilisin/kexin 9 (PCSK9) regulates VLDLR protein and triglyceride accumulation in visceral adipose tissue,” Arteriosclerosis, Thrombosis, and Vascular Biology, vol. 31, no. 4, pp. 785–791, 2011.
[53]
L. Persson, C. G？lman, B. Angelin, and M. Rudling, “Importance of proprotein convertase subtilisin/kexin type 9 in the hormonal and dietary regulation of rat liver low-density lipoprotein receptors,” Endocrinology, vol. 150, no. 3, pp. 1140–1146, 2009.
[54]
M. Melone, L. Wilsie, O. Palyha, A. Strack, and S. Rashid, “Discovery of a new role of human resistin in hepatocyte low-density lipoprotein receptor suppression mediated in part by proprotein convertase subtilisin/kexin type 9,” Journal of the American College of Cardiology, vol. 59, no. 19, pp. 1697–1705, 2012.
[55]
S. H. Jung, H. S. Park, K. Kim et al., “Effect of weight loss on some serum cytokines in human obesity: increase in IL-10 after weight loss,” Journal of Nutritional Biochemistry, vol. 19, no. 6, pp. 371–375, 2008.
[56]
N. P. Kadoglou, D. Perrea, F. Iliadis, N. Angelopoulou, C. Liapis, and M. Alevizos, “Exercise reduces resistin and inflammatory cytokines in patients with type 2 diabetes,” Diabetes Care, vol. 30, no. 3, pp. 719–721, 2007.
