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Krieger JP, Santos da Conceição EP, Sanchez-Watts G, Arnold M, Pettersen KG, Mohammed M, Modica S, Lossel P, Morrison SF, Madden CJ, Watts AG, Langhans W, Lee SJ. Glucagon-like peptide-1 regulates brown adipose tissue thermogenesis via the gut-brain axis in rats. Am J Physiol Regul Integr Comp Physiol 2018; 315:R708-R720. [PMID: 29847161 DOI: 10.1152/ajpregu.00068.2018] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Endogenous intestinal glucagon-like peptide-1 (GLP-1) controls satiation and glucose metabolism via vagal afferent neurons (VANs). Recently, VANs have received increasing attention for their role in brown adipose tissue (BAT) thermogenesis. It is, however, unclear whether VAN GLP-1 receptor (GLP-1R) signaling affects BAT thermogenesis and energy expenditure (EE) and whether this VAN mechanism contributes to energy balance. First, we tested the effect of the GLP-1R agonist exendin-4 (Ex4, 0.3 μg/kg ip) on EE and BAT thermogenesis and whether these effects require VAN GLP-1R signaling using a rat model with a selective Glp1r knockdown (kd) in VANs. Second, we examined the role of VAN GLP-1R in energy balance during chronic high-fat diet (HFD) feeding in VAN Glp1r kd rats. Finally, we used viral transsynaptic tracers to identify the possible neuronal substrates of such a gut-BAT interaction. VAN Glp1r kd attenuated the acute suppressive effects of Ex4 on EE and BAT thermogenesis. Consistent with this finding, the VAN Glp1r kd increased EE and BAT activity, diminished body weight gain, and improved insulin sensitivity compared with HFD-fed controls. Anterograde transsynaptic viral tracing of VANs infected major hypothalamic and hindbrain areas involved in BAT sympathetic regulation. Moreover, retrograde tracing from BAT combined with laser capture microdissection revealed that a population of VANs expressing Glp1r is synaptically connected to the BAT. Our findings reveal a novel role of VAN GLP-1R signaling in the regulation of EE and BAT thermogenesis and imply that through this gut-brain-BAT connection, intestinal GLP-1 plays a role in HFD-induced metabolic syndrome.
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Affiliation(s)
- Jean-Philippe Krieger
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | | | - Graciela Sanchez-Watts
- Department of Biological Sciences, University of Southern California , Los Angeles, California
| | - Myrtha Arnold
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | - Klaus G Pettersen
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | - Mazher Mohammed
- Department of Neurological Surgery, Oregon Health and Science University , Portland, Oregon
| | - Salvatore Modica
- Translational Nutrition Biology Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | - Pius Lossel
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | - Shaun F Morrison
- Department of Neurological Surgery, Oregon Health and Science University , Portland, Oregon
| | - Christopher J Madden
- Department of Neurological Surgery, Oregon Health and Science University , Portland, Oregon
| | - Alan G Watts
- Department of Biological Sciences, University of Southern California , Los Angeles, California
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
| | - Shin J Lee
- Physiology and Behavior Laboratory, Eidgenössische Technische Hochschule Zürich, Schwerzenbach, Switzerland
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Lee SJ, Sanchez-Watts G, Krieger JP, Pignalosa A, Norell PN, Cortella A, Pettersen KG, Vrdoljak D, Hayes MR, Kanoski SE, Langhans W, Watts AG. Loss of dorsomedial hypothalamic GLP-1 signaling reduces BAT thermogenesis and increases adiposity. Mol Metab 2018; 11:33-46. [PMID: 29650350 PMCID: PMC6001878 DOI: 10.1016/j.molmet.2018.03.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/09/2018] [Accepted: 03/14/2018] [Indexed: 12/15/2022] Open
Abstract
Objective Glucagon-like peptide-1 (GLP-1) neurons in the hindbrain densely innervate the dorsomedial hypothalamus (DMH), a nucleus strongly implicated in body weight regulation and the sympathetic control of brown adipose tissue (BAT) thermogenesis. Therefore, DMH GLP-1 receptors (GLP-1R) are well placed to regulate energy balance by controlling sympathetic outflow and BAT function. Methods We investigate this possibility in adult male rats by using direct administration of GLP-1 (0.5 ug) into the DMH, knocking down DMH GLP-1R mRNA with viral-mediated RNA interference, and by examining the neurochemical phenotype of GLP-1R expressing cells in the DMH using in situ hybridization. Results GLP-1 administered into the DMH increased BAT thermogenesis and hepatic triglyceride (TG) mobilization. On the other hand, Glp1r knockdown (KD) in the DMH increased body weight gain and adiposity, with a concomitant reduction in energy expenditure (EE), BAT temperature, and uncoupling protein 1 (UCP1) expression. Moreover, DMH Glp1r KD induced hepatic steatosis, increased plasma TG, and elevated liver specific de-novo lipogenesis, effects that collectively contributed to insulin resistance. Interestingly, DMH Glp1r KD increased neuropeptide Y (NPY) mRNA expression in the DMH. GLP-1R mRNA in the DMH, however, was found in GABAergic not NPY neurons, consistent with a GLP-1R-dependent inhibition of NPY neurons that is mediated by local GABAergic neurons. Finally, DMH Glp1r KD attenuated the anorexigenic effects of the GLP-1R agonist exendin-4, highlighting an important role of DMH GLP-1R signaling in GLP-1-based therapies. Conclusions Collectively, our data show that DMH GLP-1R signaling plays a key role for BAT thermogenesis and adiposity. DMH GLP-1R stimulation acutely increases BAT thermogenesis. DMH GLP-1R mRNA knockdown decreases EE and BAT thermogenesis. DMH GLP-1R mRNA knockdown impairs lipid and glucose metabolism. Reduced DMH GLP-1R signaling blunts the anorexigenic responses to Ex-4. DMH GLP-1R signaling indirectly regulates NPY gene expression.
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Affiliation(s)
- Shin J Lee
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland.
| | - Graciela Sanchez-Watts
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | | | - Angelica Pignalosa
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Puck N Norell
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Alyssa Cortella
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Klaus G Pettersen
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Dubravka Vrdoljak
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Matthew R Hayes
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Scott E Kanoski
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Alan G Watts
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
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Lee SJ, Diener K, Kaufman S, Krieger JP, Pettersen KG, Jejelava N, Arnold M, Watts AG, Langhans W. Limiting glucocorticoid secretion increases the anorexigenic property of Exendin-4. Mol Metab 2016; 5:552-565. [PMID: 27408779 PMCID: PMC4921942 DOI: 10.1016/j.molmet.2016.04.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 04/14/2016] [Accepted: 04/27/2016] [Indexed: 12/25/2022] Open
Abstract
Objective Glucagon-like peptide-1 (GLP-1) analogs are attractive options for the treatment of type II diabetes and obesity because of their incretin and anorexigenic effects. Peripheral administration of the GLP-1R agonist Exendin-4 (Ex-4) also increases glucocorticoid secretion in rodents and humans, but whether the released glucocorticoids interact with Ex-4's anorexigenic effect remains unclear. Methods To test this, we used two experimental approaches that suppress corticosterone secretion and then assessed Ex-4 effects on eating in adult male rats. First, we combined acute and chronic low dose dexamethasone treatment with Ex-4. Second, we ablated hindbrain catecholamine neurons projecting to the hypothalamus with anti-dopamine-β-hydroxylase-saporin (DSAP) to block Ex-4-induced corticosterone secretion. Results Combining dexamethasone and Ex-4 produced a larger acute anorexigenic effect than Ex-4 alone. Likewise, chronic dexamethasone and Ex-4 co-treatment produced a synergistic effect on eating and greater body weight loss in diet-induced obese rats than Ex-4 alone. DSAP lesions not only blunted Ex-4's ability to increase corticosterone secretion, but potentiated the anorexigenic effect of Ex-4, indicating that Ex-4-dependent corticosterone secretion opposes Ex-4's actions. Consistent with the enhancement of Ex-4's anorexigenic effect, DSAP lesion altered Ex-4-dependent changes in neuropeptide Y, preproglucagon, and corticotropin releasing hormone gene expression involved in glucocorticoid feedback. Conclusions Our findings demonstrate that limiting glucocorticoid secretion and actions with low dose dexamethasone or DSAP lesion increases Ex-4's ability to reduce food intake and body weight. Novel glucocorticoid receptor based mechanisms, therefore, may help enhance GLP-1-based obesity therapies. Blocking HPA axis by low dose dexamethasone increased the anorexigenic property of Ex-4. Dexamethasone/Ex-4 co-treatment reduced food intake and body weight in diet-induced obese rats more than Ex-4 alone. A brain lesion model identified a potential central interaction between glucocorticoids and GLP-1 in food intake control.
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Affiliation(s)
- Shin J Lee
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland.
| | - Katharina Diener
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Sharon Kaufman
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | | | - Klaus G Pettersen
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Nino Jejelava
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Myrtha Arnold
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
| | - Alan G Watts
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach, Switzerland
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Krieger JP, Arnold M, Pettersen KG, Lossel P, Langhans W, Lee SJ. Knockdown of GLP-1 Receptors in Vagal Afferents Affects Normal Food Intake and Glycemia. Diabetes 2016; 65:34-43. [PMID: 26470787 DOI: 10.2337/db15-0973] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/16/2015] [Indexed: 11/13/2022]
Abstract
Nutrient stimulation of enteroendocrine L cells induces the release of the incretin and satiating peptide glucagon-like peptide 1 (GLP-1). The vagus nerve innervates visceral organs and may contribute to the mediation of gut-derived GLP-1's effects on food intake, energy homeostasis, and glycemic control. To test the hypothesis that vagal afferent neuron (VAN) GLP-1 receptors (GLP-1Rs) are necessary for these effects of endogenous GLP-1, we established a novel bilateral nodose ganglia injection technique to deliver a lentiviral vector and to knock down VAN GLP-1Rs in male Sprague Dawley rats. We found that a full expression of VAN GLP-1Rs is not necessary for the maintenance of long-term energy balance in normal eating conditions. VAN GLP-1R knockdown (kd) did, however, increase meal size and accelerated gastric emptying. Moreover, postmeal glycemia was elevated and insulin release was blunted in GLP-1R kd rats, suggesting that VAN GLP-1Rs are physiological contributors to the neuroincretin effect after a meal. Collectively, our results highlight a crucial role for the VANs in mediating the effects of endogenous GLP-1 on food intake and glycemia and may promote the further development of GLP-1-based therapies.
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Affiliation(s)
- Jean-Philippe Krieger
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Myrtha Arnold
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Klaus G Pettersen
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Pius Lossel
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
| | - Shin J Lee
- Physiology and Behavior Laboratory, Institute of Food, Nutrition, and Health, ETH Zurich, Zurich, Switzerland
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