Proc Natl Acad Sci U S A. 2014 Dec 22. pii: 201421420. [Epub ahead of print]
A peripheral endocannabinoid mechanism contributes to glucocorticoid-mediated metabolic syndrome.
Bowles NP1, Karatsoreos IN2, Li X3, Vemuri VK4, Wood J4, Li Z5, Tamashiro KL6, Schwartz GJ3, Makriyannis AM4, Kunos G7, Hillard CJ8, McEwen BS1, Hill MN9.
1Laboratories of Neuroendocrinology and nbowles@mail.rockefeller.edu mcewen@mail.rockefeller.edu mnhill@ucalgary.ca.
2Laboratories of Neuroendocrinology and Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164;
3Departments of Medicine and Neuroscience, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461;
4Center for Drug Discovery, Department of Pharmaceutical Sciences and Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115;
5Molecular Genetics, The Rockefeller University, New York, NY 10065;
6Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205;
7National Institute of Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892;
8Department of Pharmacology and Toxicology and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI 53226; and.
9Laboratories of Neuroendocrinology and Departments of Cell Biology and Anatomy and Psychiatry, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada T2N 4N1 nbowles@mail.rockefeller.edu mcewen@mail.rockefeller.edu mnhill@ucalgary.ca.
Glucocorticoids are known to promote the development of metabolic syndrome through the modulation of both feeding pathways and metabolic processes; however, the precise mechanisms of these effects are not well-understood. Recent evidence shows that glucocorticoids possess the ability to increase endocannabinoid signaling, which is known to regulate appetite, energy balance, and metabolic processes through both central and peripheral pathways. The aim of this study was to determine the role of endocannabinoid signaling in glucocorticoid-mediated obesity and metabolic syndrome. Using a mouse model of excess corticosterone exposure, we found that the ability of glucocorticoids to increase adiposity, weight gain, hormonal dysregulation, hepatic steatosis, and dyslipidemia was reduced or reversed in mice lacking the cannabinoid CB1 receptor as well as mice treated with the global CB1 receptor antagonist AM251. Similarly, a neutral, peripherally restricted CB1 receptor antagonist (AM6545) was able to attenuate the metabolic phenotype caused by chronic corticosterone, suggesting a peripheral mechanism for these effects. Biochemical analyses showed that chronic excess glucocorticoid exposure produced a significant increase in hepatic and circulating levels of the endocannabinoid anandamide, whereas no effect was observed in the hypothalamus. To test the role of the liver, specific and exclusive deletion of hepatic CB1 receptor resulted in a rescue of the dyslipidemic effects of glucocorticoid exposure, while not affecting the obesity phenotype or the elevations in insulin and leptin. Together, these data indicate that glucocorticoids recruit peripheral endocannabinoid signaling to promote metabolic dysregulation, with hepatic endocannabinoid signaling being especially important for changes in lipid metabolism. |
