1. Orexin-A represses satiety-inducing POMC neurons and contributes to obesity via stimulation of endocannabinoid signaling
- Author
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Morello, Giovanna, Imperatore, Roberta, Palomba, Letizia, Finelli, Carmine, Labruna, Giuseppe, Pasanisi, Fabrizio, Sacchetti, Lucia, Buono, Lorena, Piscitelli, Fabiana, Orlando, Pierangelo, Di Marzo, Vincenzo, Cristino, Luigia, Morello, Giovanna, Imperatore, Roberta, Palomba, Letizia, Finelli, Carmine, Labruna, Giuseppe, Pasanisi, Fabrizio, Sacchetti, Lucia, Buono, Lorena, Piscitelli, Fabiana, Orlando, Pierangelo, Di Marzo, Vincenzo, and Cristino, Luigia
- Subjects
0301 basic medicine ,Male ,Pro-Opiomelanocortin ,Satiety Response ,Energy homeostasis ,Mice ,0302 clinical medicine ,2-arachidonoylglycerol ,cannabinoid type 1 receptor ,hypocretin-1 ,hypothalamus ,α–melanocyte-stimulating hormone ,Cannabinoid receptor type 1 ,Hypothalamu ,Hypocretin-1 ,Cells, Cultured ,media_common ,Neurons ,Multidisciplinary ,digestive, oral, and skin physiology ,Biological Sciences ,Endocannabinoid system ,Up-Regulation ,Hypothalamus ,hormones, hormone substitutes, and hormone antagonists ,Signal Transduction ,Adult ,medicine.medical_specialty ,media_common.quotation_subject ,Biology ,α-melanocyte-stimulating hormone ,03 medical and health sciences ,Orexin-A ,Proopiomelanocortin ,Internal medicine ,medicine ,Animals ,Humans ,Obesity ,Orexins ,Appetite ,Neural Inhibition ,?-melanocyte-stimulating hormone ,hypocretin-1 | cannabinoid type 1 receptor | 2-arachidonoylglycerol | ?-melanocyte-stimulating hormone | hypothalamus ,Mice, Inbred C57BL ,030104 developmental biology ,Endocrinology ,alpha-MSH ,Cannabinoid type 1 receptor ,Anorectic ,biology.protein ,Anterior Hypothalamic Nucleus ,030217 neurology & neurosurgery ,Endocannabinoids - Abstract
In the hypothalamic arcuate nucleus (ARC), proopiomelanocortin (POMC) neurons and the POMC-derived peptide α–melanocytestimulating hormone (α-MSH) promote satiety. POMC neurons receive orexin-A (OX-A)-expressing inputs and express both OX-A receptor type 1 (OX-1R) and cannabinoid receptor type 1 (CB1R) on the plasma membrane. OX-A is crucial for the control of wakefulness and energy homeostasis and promotes, in OX-1R–expressing cells, the biosynthesis of the endogenous counterpart of marijuana’s psychotropic and appetite-inducing component Δ9-tetrahydrocannabinol, i.e., the endocannabinoid 2-arachidonoylglycerol (2-AG), which acts at CB1R. We report that OX-A/OX-1R signaling at POMC neurons promotes 2-AG biosynthesis, hyperphagia, and weight gain by blunting α-MSH production via CB1R-induced and extracellularsignal- regulated kinase 1/2 activation- and STAT3 inhibitionmediated suppression of Pomc gene transcription. Because the systemic pharmacological blockade of OX-1R by SB334867 caused anorectic effects by reducing food intake and body weight, our results unravel a previously unsuspected role for OX-A in endocannabinoid-mediated promotion of appetite by combining OX-induced alertness with food seeking. Notably, increased OX-A trafficking was found in the fibers projecting to the ARC of obese mice (ob/ob and high-fat diet fed) concurrently with elevation of OX-A release in the cerebrospinal fluid and blood ofmice. Furthermore, a negative correlation between OX-A and α-MSH serum levels was found in obese mice as well as in human obese subjects (body mass index > 40), in combination with elevation of alanine aminotransferase and γ-glutamyl transferase, two markers of fatty liver disease. These alterations were counteracted by antagonism of OX-1R, thus providing the basis for a therapeutic treatment of these diseases
- Published
- 2016
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