Ursolic acid increases energy expenditure through enhancing free fatty acid uptake and β-oxidation via an UCP3/AMPK-dependent pathway in skeletal muscle.

SCOPE Ursolic acid (UA) is a triterpenoid compound with multifold biological functions. Our previous studies have reported that UA protects against high-fat diet-induced obesity and improves insulin resistance (IR). However, the potential mechanisms are still undefined. Free fatty acid (FFA) metabolism in skeletal muscle plays a central role in obesity and IR. Therefore, in this study, we investigated the effect and the potential mechanisms of UA on skeletal muscle FFA metabolism. METHODS AND RESULTS In diet-induced obese rats, 0.5% UA supplementation for 6 weeks markedly reduced body weight, increased energy expenditure, decreased FFA level in serum and skeletal muscle and triglyceride content in skeletal muscle. In vitro, the data provided directly evidence that UA significantly increased fluorescently labeled FFA uptake and (3) H-labeled palmitic acid β-oxidation. UA-activated AMP-activated protein kinase (AMPK) and downstream targets were involved in the increase of FFA catabolism. Moreover, upregulated uncoupling protein 3 (UCP3) by UA contributed to AMPK activation via elevating adenosine monophosphate/adenosine triphosphate ratio. CONCLUSION UA increases FFA burning through enhancing skeletal muscle FFA uptake and β-oxidation via an UCP3/AMPK-dependent pathway, which provides a novel perspective on the biological function of UA against obesity and IR.

[1]  Haisong Zhang,et al.  Suppression of oxidative stress and improvement of liver functions in mice by ursolic acid via LKB1‐AMP‐activated protein kinase signaling , 2015, Journal of gastroenterology and hepatology.

[2]  T. Radhiga,et al.  Effect of ursolic acid and Rosiglitazone combination on hepatic lipid accumulation in high fat diet-fed C57BL/6J mice. , 2014, European journal of pharmacology.

[3]  Fanyu Meng,et al.  Therapeutic Role of Ursolic Acid on Ameliorating Hepatic Steatosis and Improving Metabolic Disorders in High-Fat Diet-Induced Non-Alcoholic Fatty Liver Disease Rats , 2014, PloS one.

[4]  Sung-Hoon Kim,et al.  Activation of AMP‐activated Protein Kinase and Phosphorylation of Glycogen Synthase Kinase3 β Mediate Ursolic Acid Induced Apoptosis in HepG2 Liver Cancer Cells , 2013, Phytotherapy research : PTR.

[5]  Y. Li,et al.  Ursolic Acid Inhibits Adipogenesis in 3T3-L1 Adipocytes through LKB1/AMPK Pathway , 2013, PloS one.

[6]  A. Sundaresan,et al.  Ursolic acid and rosiglitazone combination alleviates metabolic syndrome in high fat diet fed C57BL/6J mice. , 2012, General physiology and biophysics.

[7]  Dmitri Samovski,et al.  Insulin and AMPK regulate FA translocase/CD36 plasma membrane recruitment in cardiomyocytes via Rab GAP AS160 and Rab8a Rab GTPase , 2012, Journal of Lipid Research.

[8]  Guo-Hui Zhang,et al.  Ursolic acid-induced AMP-activated protein kinase (AMPK) activation contributes to growth inhibition and apoptosis in human bladder cancer T24 cells. , 2012, Biochemical and biophysical research communications.

[9]  Y. Li,et al.  Mangiferin Decreases Plasma Free Fatty Acids through Promoting Its Catabolism in Liver by Activation of AMPK , 2012, PloS one.

[10]  S. Ullevig,et al.  Ursolic acid protects diabetic mice against monocyte dysfunction and accelerated atherosclerosis. , 2011, Atherosclerosis.

[11]  R. Feng,et al.  Beneficial effects of mangiferin on hyperlipidemia in high-fat-fed hamsters. , 2011, Molecular nutrition & food research.

[12]  M. G. Queiroz,et al.  Ursolic acid, a pentacyclic triterpene from Sambucus australis, prevents abdominal adiposity in mice fed a high-fat diet. , 2011, Journal of medicinal food.

[13]  V. Holla,et al.  Nuclear Orphan Receptor NR4A2 Modulates Fatty Acid Oxidation Pathways in Colorectal Cancer* , 2011, The Journal of Biological Chemistry.

[14]  Julius Liobikas,et al.  Uncoupling and antioxidant effects of ursolic acid in isolated rat heart mitochondria. , 2011, Journal of natural products.

[15]  Y. Li,et al.  Ursolic acid stimulates lipolysis in primary-cultured rat adipocytes. , 2010, Molecular nutrition & food research.

[16]  Y. Li,et al.  Free fatty acid metabolic profile and biomarkers of isolated post-challenge diabetes and type 2 diabetes mellitus based on GC-MS and multivariate statistical analysis. , 2010, Journal of chromatography. B, Analytical technologies in the biomedical and life sciences.

[17]  Kyoung-Sik Park.  Raspberry ketone increases both lipolysis and fatty acid oxidation in 3T3-L1 adipocytes. , 2010, Planta medica.

[18]  Mi-Kyung Lee,et al.  Inhibitory effects of ursolic acid on hepatic polyol pathway and glucose production in streptozotocin-induced diabetic mice. , 2010, Metabolism: clinical and experimental.

[19]  Mengwei Zang,et al.  AMPK as a metabolic tumor suppressor: control of metabolism and cell growth. , 2010, Future oncology.

[20]  Wenjun Ding,et al.  Evaluation of inhibition of fatty acid synthase by ursolic acid: positive cooperation mechanism. , 2010, Biochemical and biophysical research communications.

[21]  D. Jang,et al.  Anti-lipase and lipolytic activities of ursolic acid isolated from the roots of Actinidia arguta , 2009, Archives of pharmacal research.

[22]  Chang-hao Sun,et al.  Gossypin up-regulates LDL receptor through activation of ERK pathway: a signaling mechanism for the hypocholesterolemic effect. , 2008, Journal of agricultural and food chemistry.

[23]  B. Kemp,et al.  AMPK‐independent pathways regulate skeletal muscle fatty acid oxidation , 2008, The Journal of physiology.

[24]  M. Yin,et al.  Antioxidative and anti-inflammatory protection of oleanolic acid and ursolic acid in PC12 cells. , 2008, Journal of food science.

[25]  M. Harper,et al.  The energetic implications of uncoupling protein-3 in skeletal muscle. , 2007, Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme.

[26]  F. Capel,et al.  Resistance to high-fat-diet-induced obesity and sexual dimorphism in the metabolic responses of transgenic mice with moderate uncoupling protein 3 overexpression in glycolytic skeletal muscles , 2007, Diabetologia.

[27]  G. Shulman,et al.  Overexpression of uncoupling protein 3 in skeletal muscle protects against fat-induced insulin resistance. , 2007, The Journal of clinical investigation.

[28]  Jiajun Zhao,et al.  High-fat diet feeding impairs both the expression and activity of AMPKa in rats' skeletal muscle. , 2006, Biochemical and biophysical research communications.

[29]  B. Jayaprakasam,et al.  Amelioration of obesity and glucose intolerance in high-fat-fed C57BL/6 mice by anthocyanins and ursolic acid in Cornelian cherry (Cornus mas). , 2006, Journal of agricultural and food chemistry.

[30]  A. Bonen,et al.  Constitutive UCP3 overexpression at physiological levels increases mouse skeletal muscle capacity for fatty acid transport and oxidation , 2005, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[31]  C. Stehouwer,et al.  Free fatty acid levels modulate microvascular function: relevance for obesity-associated insulin resistance, hypertension, and microangiopathy. , 2004, Diabetes.

[32]  D. Hardie.  The AMP-activated protein kinase pathway – new players upstream and downstream , 2004, Journal of Cell Science.

[33]  Sung Hee Choi,et al.  Visceral fat thickness measured by ultrasonography can estimate not only visceral obesity but also risks of cardiovascular and metabolic diseases. , 2004, The American journal of clinical nutrition.

[34]  J. Clapham,et al.  Increased fatty acid oxidation in transgenic mice overexpressing UCP3 in skeletal muscle , 2003, Diabetes, obesity & metabolism.

[35]  M. Lacaille‐Dubois,et al.  A review of natural and modified betulinic, ursolic and echinocystic acid derivatives as potential antitumor and anti-HIV agents. , 2003, Mini reviews in medicinal chemistry.

[36]  Sanjeev Banerjee,et al.  Ursolic Acid Inhibits Nuclear Factor-κB Activation Induced by Carcinogenic Agents through Suppression of IκBα Kinase and p65 Phosphorylation: Correlation with Down-Regulation of Cyclooxygenase 2, Matrix Metalloproteinase 9, and Cyclin D1 , 2003 .

[37]  A. Bonen,et al.  Contraction-induced fatty acid translocase/CD36 translocation in rat cardiac myocytes is mediated through AMP-activated protein kinase signaling. , 2003, Diabetes.

[38]  P. Neufer,et al.  AMP-activated protein kinase activates transcription of the UCP3 and HKII genes in rat skeletal muscle. , 2002, American journal of physiology. Endocrinology and metabolism.

[39]  C. Erlanson‐Albertsson.  Uncoupling Proteins—a New Family of Proteins With Unknown Function , 2002, Nutritional neuroscience.

[40]  C. Kahn,et al.  Insulin signalling and the regulation of glucose and lipid metabolism , 2001, Nature.

[41]  F. Villarroya,et al.  Overexpression of UCP3 in cultured human muscle lowers mitochondrial membrane potential, raises ATP/ADP ratio, and favors fatty acid versus glucose oxidation , 2001, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[42]  G. Vallega,et al.  UCP-3 expression in skeletal muscle: effects of exercise, hypoxia, and AMP-activated protein kinase. , 2000, American journal of physiology. Endocrinology and metabolism.

[43]  J. Halter,et al.  Relation of weight gain and weight loss on subsequent diabetes risk in overweight adults , 2000, Journal of epidemiology and community health.

[44]  Martin D. Brand,et al.  Mice overexpressing human uncoupling protein-3 in skeletal muscle are hyperphagic and lean , 2000, Nature.

[45]  L. Leon,et al.  Lack of Obesity and Normal Response to Fasting and Thyroid Hormone in Mice Lacking Uncoupling Protein-3* , 2000, The Journal of Biological Chemistry.

[46]  V. Mootha,et al.  Energy Metabolism in Uncoupling Protein 3 Gene Knockout Mice* , 2000, The Journal of Biological Chemistry.

[47]  M. Reitman,et al.  Uncoupling Protein-3 Is a Mediator of Thermogenesis Regulated by Thyroid Hormone, β3-Adrenergic Agonists, and Leptin* , 1997, The Journal of Biological Chemistry.

[48]  O. Boss,et al.  Uncoupling protein‐3: a new member of the mitochondrial carrier family with tissue‐specific expression , 1997, FEBS letters.

[49]  D. Hardie,et al.  Role of the AMP-activated protein kinase in the cellular stress response , 1994, Current Biology.

[50]  J. Folch,et al.  A simple method for the isolation and purification of total lipides from animal tissues. , 1957, The Journal of biological chemistry.

[51]  S. Wakil,et al.  Fatty acid metabolism: target for metabolic syndrome This work is supported by grants from the National Institute of Health (GM-63115), the Hefni Technical Training Foundation, and the Medallion Foundation. Published, JLR Papers in Press, December 1, 2008. , 2009, Journal of Lipid Research.

[52]  D. Hardie,et al.  Improved glucose homeostasis in mice overexpressing human UCP3: a role for AMP-kinase? , 2004, International Journal of Obesity.

[53]  B. Viollet,et al.  The AMP-activated protein kinase alpha2 catalytic subunit controls whole-body insulin sensitivity. , 2003, The Journal of clinical investigation.

[54]  E. Ravussin,et al.  Skeletal muscle uncoupling protein 3 expression is a determinant of energy expenditure in Pima Indians. , 1999, Diabetes.