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Xie X, Zhang M, Luo H. Regulation of metabolism by circadian rhythms: Support from time-restricted eating, intestinal microbiota & omics analysis. Life Sci 2024; 351:122814. [PMID: 38857654 DOI: 10.1016/j.lfs.2024.122814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 05/05/2024] [Accepted: 06/04/2024] [Indexed: 06/12/2024]
Abstract
Circadian oscillatory system plays a key role in coordinating the metabolism of most organisms. Perturbation of genetic effects and misalignment of circadian rhythms result in circadian dysfunction and signs of metabolic disorders. The eating-fasting cycle can act on the peripheral circadian clocks, bypassing the photoperiod. Therefore, time-restricted eating (TRE) can improve metabolic health by adjusting eating rhythms, a process achieved through reprogramming of circadian genomes and metabolic programs at different tissue levels or remodeling of the intestinal microbiota, with omics technology allowing visualization of the regulatory processes. Here, we review recent advances in circadian regulation of metabolism, focus on the potential application of TRE for rescuing circadian dysfunction and metabolic disorders with the contribution of intestinal microbiota in between, and summarize the significance of omics technology.
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Affiliation(s)
- Ximei Xie
- State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, PR China
| | - Mengjie Zhang
- State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, PR China
| | - Hailing Luo
- State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, PR China.
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Lu Y, Wang L, Luo F, Savani R, Rossi MA, Pang ZP. Dorsolateral septum GLP-1R neurons regulate feeding via lateral hypothalamic projections. Mol Metab 2024; 85:101960. [PMID: 38763494 PMCID: PMC11153235 DOI: 10.1016/j.molmet.2024.101960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 05/08/2024] [Accepted: 05/15/2024] [Indexed: 05/21/2024] Open
Abstract
OBJECTIVE Although glucagon-like peptide 1 (GLP-1) is known to regulate feeding, the central mechanisms contributing to this function remain enigmatic. Here, we aim to test the role of neurons expressing GLP-1 receptors (GLP-1R) in the dorsolateral septum (dLS; dLSGLP-1R) that project to the lateral hypothalamic area (LHA) on food intake and determine the relationship with feeding regulation. METHODS Using chemogenetic manipulations, we assessed how activation or inhibition of dLSGLP-1R neurons affected food intake in Glp1r-ires-Cre mice. Then, we used channelrhodopsin-assisted circuit mapping, chemogenetics, and electrophysiological recordings to identify and assess the role of the pathway from dLSGLP-1R →LHA projections in regulating food intake. RESULTS Chemogenetic inhibition of dLSGLP-1R neurons increases food intake. LHA is a major downstream target of dLSGLP-1R neurons. The dLSGLP-1R→LHA projections are GABAergic, and chemogenetic inhibition of this pathway also promotes food intake. While chemogenetic activation of dLSGLP-1R→LHA projections modestly decreases food intake, optogenetic stimulation of the dLSGLP-1R→LHA projection terminals in the LHA rapidly suppresses feeding behavior. Finally, we demonstrate that the GLP-1R agonist, Exendin 4 enhances dLSGLP-1R →LHA GABA release. CONCLUSIONS Together, these results demonstrate that dLS-GLP-1R neurons and the inhibitory pathway to LHA can regulate feeding behavior, which might serve as a potential therapeutic target for the treatment of eating disorders or obesity.
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Affiliation(s)
- Yi Lu
- Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Le Wang
- Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Fang Luo
- Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Rohan Savani
- Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Mark A Rossi
- Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA; Department of Psychiatry, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA; Brain Health Institute, Rutgers University, New Brunswick, NJ 08901, USA; Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA.
| | - Zhiping P Pang
- Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA; Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA.
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Lu Y, Wang L, Luo F, Savani R, Rossi MA, Pang ZP. Dorsolateral septum GLP-1R neurons regulate feeding via lateral hypothalamic projections. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.26.586855. [PMID: 38585874 PMCID: PMC10996601 DOI: 10.1101/2024.03.26.586855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Objective Although glucagon-like peptide 1 (GLP-1) is known to regulate feeding, the central mechanisms contributing to this function remain enigmatic. Here, we aim to test the role of neurons expressing GLP-1 receptors (GLP-1R) in the dorsolateral septum (dLS; dLS GLP-1R ) and their downstream projections on food intake and determine the relationship with feeding regulation. Methods Using chemogenetic manipulations, we assessed how activation or inhibition of dLS GLP-1R neurons affected food intake in Glp1r-ires-Cre mice. Then, we used channelrhodopsin-assisted circuit mapping, chemogenetics, and electrophysiological recordings to identify and assess the role of the pathway from dLS GLP-1R neurons to the lateral hypothalamic area (LHA) in regulating food intake. Results Chemogenetic inhibition of dLS GLP-1R neurons increases food intake. LHA is a major downstream target of dLS GLP-1R neurons. The dLS GLP-1R →LHA projections are GABAergic, and chemogenetic inhibition of this pathway also promotes food intake. While chemogenetic activation of dLS GLP-1R →LHA projections modestly decreases food intake, optogenetic stimulation of the dLS GLP-1R →LHA projection terminals in the LHA rapidly suppressed feeding behavior. Finally, we demonstrate that the GLP-1R agonist, Exendin 4 enhances dLS GLP-1R →LHA GABA release. Conclusions Together, these results demonstrate that dLS-GLP-1R neurons and the inhibitory pathway to LHA can regulate feeding behavior, which might serve as a potential therapeutic target for the treatment of eating disorders or obesity. Highlights Chemogenetic inhibition of dLS GLP-1R neurons boosts food intake in mice dLS GLP-1R neuron activation does not alter feeding, likely by collateral inhibition dLS GLP-1R neurons project to LHA and release GABA Activation of dLS GLP-1R →LHA axonal terminals suppresses food intake GLP-1R agonism enhances dLS GLP-1R →LHA GABA release via a presynaptic mechanism.
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Wang L, Savani R, Bernabucci M, Lu Y, Singh I, Xu W, El Ouaamari A, Wheeler MB, Grill HJ, Rossi MA, Pang ZP. State-dependent central synaptic regulation by GLP-1 is essential for energy homeostasis. RESEARCH SQUARE 2024:rs.3.rs-3929981. [PMID: 38559032 PMCID: PMC10980146 DOI: 10.21203/rs.3.rs-3929981/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Central nervous system (CNS) control of metabolism plays a pivotal role in maintaining energy homeostasis. Glucagon-like peptide-1 (GLP-1, encoded by Gcg), secreted by a distinct population of neurons located within the nucleus tractus solitarius (NTS), suppresses feeding through projections to multiple brain targets1-3. Although GLP-1 analogs are proven clinically effective in treating type 2 diabetes and obesity4, the mechanisms of GLP-1 action within the brain remain unclear. Here, we investigate the involvement of GLP-1 receptor (GLP-1R) mediated signaling in a descending circuit formed by GLP-1R neurons in the paraventricular hypothalamic nucleus (PVNGLP-1R) that project to dorsal vagal complex (DVC) neurons of the brain stem in mice. PVNGLP- 1R→DVC synapses release glutamate that is augmented by GLP-1 via a presynaptic mechanism. Chemogenetic activation of PVNGLP-1R→DVC neurons suppresses feeding. The PVNGLP-1R→DVC synaptic transmission is dynamically regulated by energy states. In a state of energy deficit, synaptic strength is weaker but is more profoundly augmented by GLP-1R signaling compared to an energy-replete state. In an obese state, the dynamic synaptic strength changes in the PVNGLP-1R→DVC descending circuit are disrupted. Blocking PVNGLP-1R→DVC synaptic release or ablation of GLP-1R in the presynaptic compartment increases food intake and causes obesity, elevated blood glucose, and impaired insulin sensitivity. These findings suggest that the state-dependent synaptic plasticity in this PVNGLP-1R→DVC descending circuit mediated by GLP-1R signaling is an essential regulator of energy homeostasis.
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Affiliation(s)
- Le Wang
- The Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Rohan Savani
- The Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Matteo Bernabucci
- The Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Yi Lu
- The Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Ishnoor Singh
- The Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
- Department of Physiology, University of Toronto, Ontario, Canada
| | - Wei Xu
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX, USA
| | | | | | - Harvey J. Grill
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Mark A. Rossi
- The Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
- Department of Psychiatry, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
- Brain Health Institute, Rutgers University, New Brunswick, NJ, USA
| | - Zhiping P. Pang
- The Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
- Department of Pediatrics, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
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Huang J, Hua F, Jiang X, Zhang X, Yang M, Wang L, Huang X, Luo K. Effects of dulaglutide combined with insulin degludec on glucose fluctuations and appetite in type 2 diabetes. Front Endocrinol (Lausanne) 2023; 14:1130470. [PMID: 37255975 PMCID: PMC10225703 DOI: 10.3389/fendo.2023.1130470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/27/2023] [Indexed: 06/01/2023] Open
Abstract
Introduction The aim of this study was to describe appetite and glucose fluctuation in type 2 diabetes mellitus patients initiating treatment with dulaglutide combined with insulin degludec. Methods This retrospective study of patients identified adults starting treatment with once-weekly (QW) dulaglutide combined with insulin degludec (experimental group) or insulin degludec alone (control group). Patients were followed for up to 6 months from treatment initiation. The clinical characteristics of patients, treatment patterns, CGM data, and appetite scores were obtained for the two groups. Results A total of 236 patients were included in this study. SDBG, MAGE, LAGE, and PPGE of the experimental group were lower than the control group's (P < 0.05). The proportions of patients achieving a time in range (TIR) of ≥70% in the experimental group were higher than in the control group, with 43% and 10% on the second day, 88% and 47% on the fourth day, 95% and 47% on the seventh day, and 100% and 67% on the tenth day, respectively. Significant associations existed between TIR and the prevalence of islet function. At six months, 89.2% of patients in the experimental group were still using dulaglutide. Appetite decreased significantly at 1 week and increased at 3 months after treatment with dulaglutide. Conclusion Dulaglutide combined with insulin degludec significantly reduces glucose fluctuations in patients with type 2 diabetes mellitus and improves the TIR rate. However, the treatment on appetite could decrease in the first three months.
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Affiliation(s)
- Jinxin Huang
- Endocrinology Department, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Fei Hua
- Endocrinology Department, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Xiaohong Jiang
- Endocrinology Department, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Xingguang Zhang
- Endocrinology Department, The Seventh Medical Center of PLA General Hospital, Beijing, China
| | - Minxing Yang
- Endocrinology Department, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Long Wang
- Endocrinology Department, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Xiaolin Huang
- Endocrinology Department, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Kaiming Luo
- Endocrinology Department, The Third Affiliated Hospital of Soochow University, Changzhou, China
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Luo W, Li L, Zhang Y, Xu Z, Xiong Y, Guo Z, Zhang N, Zhang Y, Chen P, Wang Y, Du Z. Study on the Hyperglycemic Effect of GLP-1 in Spinibarbus denticulatus by Oral Administration and Intraperitoneal Injection Methods. AQUACULTURE NUTRITION 2023; 2023:9969406. [PMID: 37051050 PMCID: PMC10085660 DOI: 10.1155/2023/9969406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/14/2023] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
Glucagon-like peptide-1 (GLP-1), one of the expression products of the proglucagon (pg) gene, is an incretin mainly secreted by the gastrointestinal system. In mammals, GLP-1 has hypoglycemic and food-inhibiting effects; while in some fish species, it has been confirmed to increase blood glucose by promoting gluconeogenesis and stimulating glycogenolysis. In order to more deeply understand the role of GLP-1 in the process of glycometabolism in herbivorous fish, the pg gene was cloned from Spinibarbus denticulatus to obtain its sequence characteristics, and the changes in blood glucose level and pg gene expression in S. denticulatus were further explored by feeding with three kinds of carbohydrates and intraperitoneal injection of GLP-1. Basal and temporal blood glucose levels and pg gene expression of S. denticulatus (91.68 ± 10.79 g) were measured at 0, 1, 3, 5, 7, and 12 h after oral administration (n = 4). Then, the changes of blood glucose levels and pg and glucokinase (gk) gene expressions of S. denticulatus (94.29 ± 10.82 g) were determined at 0, 30, 60, and 120 min after intraperitoneal injection (n = 4). It was shown that polysaccharides could induce the upregulation of pg gene expression faster than monosaccharides and stimulate the secretion of GLP-1 in the intestine. Intraperitoneal injection of GLP-1 peptide rapidly raised blood glucose levels, and pg gene expression in the anterior intestine, whole brain, and hepatopancreas decreased continuously after 30 minutes. These results showed that S. denticulatus might inhibit the excessive accumulation of blood glucose by reducing the expression of the pg gene and increasing the expression of gk gene in a short time. It was speculated that GLP-1 of S. denticulatus might have a "gut-brain-liver" pathway similar to mammals in glycemia regulation. Therefore, this study provided a novel perspective for explaining the functional differences of GLP-1 in herbivorous fish and mammals.
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Affiliation(s)
- Wei Luo
- College of Animal Science and Technology, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, China
| | - Luojia Li
- College of Animal Science and Technology, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, China
| | - Yue Zhang
- College of Animal Science and Technology, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, China
| | - Zhou Xu
- Mianyang Academy of Agricultural Sciences, Mianyang, Sichuan, China
| | - Yinlin Xiong
- The Original Stock Farm of Leiocassis longirostris of Sichuan Province, Chongzhou, Sichuan, China
| | - Zhonggang Guo
- Agricultural and Rural Bureau of Chongzhou, Chongzhou, Sichuan, China
| | - Ning Zhang
- College of Animal Science and Technology, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, China
| | - Yibo Zhang
- College of Animal Science and Technology, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, China
| | - Pengyu Chen
- College of Animal Science and Technology, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, China
| | - Yan Wang
- College of Animal Science and Technology, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, China
| | - Zongjun Du
- College of Animal Science and Technology, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, China
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Pugh JE, Cai M, Altieri N, Frost G. A comparison of the effects of resistant starch types on glycemic response in individuals with type 2 diabetes or prediabetes: A systematic review and meta-analysis. Front Nutr 2023; 10:1118229. [PMID: 37051127 PMCID: PMC10085630 DOI: 10.3389/fnut.2023.1118229] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 01/30/2023] [Indexed: 03/29/2023] Open
Abstract
Background Type 2 diabetes (T2D) diagnoses are predicted to reach 643 million by 2030, increasing incidences of cardiovascular disease and other comorbidities. Rapidly digestible starch elevates postprandial glycemia and impinges glycemic homeostasis, elevating the risk of developing T2D. Starch can escape digestion by endogenous enzymes in the small intestine when protected by intact plant cell walls (resistant starch type 1), when there is a high concentration of amylose (resistant starch type 2) and when the molecule undergoes retrogradation (resistant starch type 3) or chemical modification (resistant starch type 4). Dietary interventions using resistant starch may improve glucose metabolism and insulin sensitivity. However, few studies have explored the differential effects of resistant starch type. This systematic review and meta-analysis aims to compare the effects of the resistant starch from intact plant cell structures (resistant starch type 1) and resistant starch from modified starch molecules (resistant starch types 2-5) on fasting and postprandial glycemia in subjects with T2D and prediabetes. Methods Databases (PubMed, SCOPUS, Ovid MEDLINE, Cochrane, and Web of Science) were systematically searched for randomized controlled trials. Standard mean difference (SMD) with 95% confidence intervals (CI) were determined using random-effects models. Sub-group analyses were conducted between subjects with T2D versus prediabetes and types of resistant starch. Results The search identified 36 randomized controlled trials (n = 982), 31 of which could be included in the meta-analysis. Resistant starch type 1 and type 2 lowered acute postprandial blood glucose [SMD (95% CI) = -0.54 (-1.0, -0.07)] and [-0.96 (-1.61, -0.31)]. Resistant starch type 2 improved acute postprandial insulin response [-0.71 (-1.31, -0.11)]. In chronic studies, resistant starch type 1 and 2 lowered postprandial glucose [-0.38 (-0.73, -0.02), -0.29 (-0.53, -0.04), respectively] and resistant starch type 2 intake improved fasting glucose [-0.39 (-0.66, -0.13)] and insulin [-0.40 (-0.60, -0.21)]. Conclusion Resistant starch types 1 and 2 may influence glucose homeostasis via discrete mechanisms, as they appear to influence glycemia differently. Further research into resistant starch types 3, 4, and 5 is required to elucidate their effect on glucose metabolism. The addition of resistant starch as a dietary intervention for those with T2D or prediabetes may prevent further deterioration of glycemic control.
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Affiliation(s)
| | | | | | - Gary Frost
- Section for Nutrition Research, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, Hammersmith Campus, London, United Kingdom
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Chen J, Mei A, Wei Y, Li C, Qian H, Min X, Yang H, Dong L, Rao X, Zhong J. GLP-1 receptor agonist as a modulator of innate immunity. Front Immunol 2022; 13:997578. [PMID: 36569936 PMCID: PMC9772276 DOI: 10.3389/fimmu.2022.997578] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 11/24/2022] [Indexed: 12/12/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) is a 30-amino acid hormone secreted by L cells in the distal ileum, colon, and pancreatic α cells, which participates in blood sugar regulation by promoting insulin release, reducing glucagon levels, delaying gastric emptying, increasing satiety, and reducing appetite. GLP-1 specifically binds to the glucagon-like peptide-1 receptor (GLP-1R) in the body, directly stimulating the secretion of insulin by pancreatic β-cells, promoting proliferation and differentiation, and inhibiting cell apoptosis, thereby exerting a glycemic lowering effect. The glycemic regulating effect of GLP-1 and its analogues has been well studied in human and murine models in the circumstance of many diseases. Recent studies found that GLP-1 is able to modulate innate immune response in a number of inflammatory diseases. In the present review, we summarize the research progression of GLP-1 and its analogues in immunomodulation and related signal pathways.
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Affiliation(s)
- Jun Chen
- Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Hubei Key Laboratory of Wudang Local Chinese Medicine Research (Hubei University of Medicine), Shiyan, China
| | - Aihua Mei
- Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Hubei Key Laboratory of Wudang Local Chinese Medicine Research (Hubei University of Medicine), Shiyan, China
| | - Yingying Wei
- Department of Rheumatology and Immunology, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chunlei Li
- Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Hubei Key Laboratory of Wudang Local Chinese Medicine Research (Hubei University of Medicine), Shiyan, China
| | - Hang Qian
- Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Hubei Key Laboratory of Wudang Local Chinese Medicine Research (Hubei University of Medicine), Shiyan, China
| | - Xinwen Min
- Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Hubei Key Laboratory of Wudang Local Chinese Medicine Research (Hubei University of Medicine), Shiyan, China
| | - Handong Yang
- Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Hubei Key Laboratory of Wudang Local Chinese Medicine Research (Hubei University of Medicine), Shiyan, China
| | - Lingli Dong
- Department of Rheumatology and Immunology, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China,*Correspondence: Jixin Zhong, ; Xiaoquan Rao, ; Lingli Dong,
| | - Xiaoquan Rao
- Department of Cardiology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China,*Correspondence: Jixin Zhong, ; Xiaoquan Rao, ; Lingli Dong,
| | - Jixin Zhong
- Department of Rheumatology and Immunology, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China,*Correspondence: Jixin Zhong, ; Xiaoquan Rao, ; Lingli Dong,
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Singh I, Wang L, Xia B, Liu J, Tahiri A, El Ouaamari A, Wheeler MB, Pang ZP. Activation of arcuate nucleus glucagon-like peptide-1 receptor-expressing neurons suppresses food intake. Cell Biosci 2022; 12:178. [PMID: 36309763 PMCID: PMC9618215 DOI: 10.1186/s13578-022-00914-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/11/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Central nervous system (CNS) control of metabolism plays a pivotal role in maintaining energy balance. In the brain, Glucagon-like peptide 1 (GLP-1), encoded by the proglucagon 'Gcg' gene, produced in a distinct population of neurons in the nucleus tractus solitarius (NTS), has been shown to regulate feeding behavior leading to the suppression of appetite. However, neuronal networks that mediate endogenous GLP-1 action in the CNS on feeding and energy balance are not well understood. RESULTS We analyzed the distribution of GLP-1R-expressing neurons and axonal projections of NTS GLP-1-producing neurons in the mouse brain. GLP-1R neurons were found to be broadly distributed in the brain and specific forebrain regions, particularly the hypothalamus, including the arcuate nucleus of the hypothalamus (ARC), a brain region known to regulate energy homeostasis and feeding behavior, that receives dense NTSGcg neuronal projections. The impact of GLP-1 signaling in the ARC GLP-1R-expressing neurons and the impact of activation of ARC GLP-1R on food intake was examined. Application of GLP-1R specific agonist Exendin-4 (Exn-4) enhanced a proportion of the ARC GLP-1R-expressing neurons and pro-opiomelanocortin (POMC) neuronal action potential firing rates. Chemogenetic activation of the ARC GLP-1R neurons by using Cre-dependent hM3Dq AAV in the GLP-1R-ires-Cre mice, established that acute activation of the ARC GLP-1R neurons significantly suppressed food intake but did not have a strong impact on glucose homeostasis. CONCLUSIONS These results highlight the importance of central GLP-1 signaling in the ARC that express GLP-1R that upon activation, regulate feeding behavior.
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Affiliation(s)
- Ishnoor Singh
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.17063.330000 0001 2157 2938Department of Physiology, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 1A8 Canada
| | - Le Wang
- The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA.
| | - Baijuan Xia
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.413458.f0000 0000 9330 9891School of Basic Medical Sciences, Guizhou Medical University, Guiyang, Guizhou, 550025 China
| | - Ji Liu
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.59053.3a0000000121679639National Engineering Laboratory for Brain-Inspired Intelligence Technology and Application, School of Information Science and Technology, University of Science and Technology of China, Hefei, 230026 Anhui China
| | - Azeddine Tahiri
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA
| | - Abdelfattah El Ouaamari
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.430387.b0000 0004 1936 8796Department of Medicine, Division of Endocrinology, Metabolism and Nutrition, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA
| | - Michael B. Wheeler
- grid.17063.330000 0001 2157 2938Department of Physiology, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 1A8 Canada ,Metabolism Research Group, Division of Advanced Diagnostics, Toronto, ON Canada
| | - Zhiping P. Pang
- grid.430387.b0000 0004 1936 8796The Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.430387.b0000 0004 1936 8796Department of Neuroscience and Cell Biology, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA ,grid.430387.b0000 0004 1936 8796Department of Pediatrics, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 USA
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Winquist RJ, Gribkoff VK. Cardiovascular effects of GLP-1 receptor agonism. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2022; 94:213-254. [PMID: 35659373 DOI: 10.1016/bs.apha.2022.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) receptor agonists are extensively used in type 2 diabetic patients for the effective control of hyperglycemia. It is now clear from outcomes trials that this class of drugs offers important additional benefits to these patients due to reducing the risk of developing major adverse cardiac events (MACE). This risk reduction is, in part, due to effective glycemic control in patients; however, the various outcomes trials, further validated by subsequent meta-analysis of the outcomes trials, suggest that the risk reduction in MACE is also dependent on glycemic-independent mechanisms operant in cardiovascular tissues. These glycemic-independent mechanisms are likely mediated by GLP-1 receptors found throughout the cardiovascular system and by the complex signaling cascades triggered by the binding of agonists to the G-protein coupled receptors. This heterogeneity of signaling pathways underlying different downstream effects of GLP-1 agonists, and the discovery of biased agonists favoring specific signaling pathways, may have import in the future treatment of MACE in these patients. We review the evidence supporting the glycemic-independent evidence for risk reduction of MACE by the GLP-1 receptor agonists and highlight the putative mechanisms underlying these benefits. We also comment on the different signaling pathways which appear important for mediating these effects.
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Affiliation(s)
| | - Valentin K Gribkoff
- Section on Endocrinology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States; TheraStat LLC, Weston, MA, United States
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11
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Lu Z, Chan SW, Tu L, Ngan MP, Rudd JA. GLP-1 receptors are involved in the GLP-1 (7-36) amide-induced modulation of glucose homoeostasis, emesis and feeding in Suncus murinus (house musk shrew). Eur J Pharmacol 2020; 888:173528. [PMID: 32871177 DOI: 10.1016/j.ejphar.2020.173528] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/25/2020] [Accepted: 08/28/2020] [Indexed: 12/25/2022]
Abstract
GLP-1 receptor agonists are used for the treatment of type 2 diabetes but they may reduce appetite and cause nausea and emesis. We investigated if GLP-1 (7-36) amide can modulate glucose homoeostasis, emesis and feeding via an exendin (9-39)-sensitive mechanism in Suncus murinus. The effect of GLP-1 (7-36) amide on glucose homeostasis was examined using an intraperitoneal glucose tolerance test. In conscious fasted animals, food and water consumption and behavior were measured for 1 h following drug administration. c-Fos expression in the brain was measured using immunohistochemistry. GLP-1 (7-36) amide reduced blood glucose levels dose-dependently. Exendin (9-39) did not modify blood glucose levels but suppressed the glucose-lowering effect of GLP-1 (7-36) amide. GLP-1 (7-36) amide inhibited food and water intake, induced emesis and elevated c-Fos expression in the brainstem and hypothalamic nuclei in the brain. Exendin (9-39) antagonised the inhibition of food and water intake and emesis induced by GLP-1 (7-36) amide and the effects on c-Fos expression in the hypothalamus and brainstem, excepting for the bed nucleus of the stria terminalis. These data suggest that the action of GLP-1 (7-36) amide to modulate blood glucose, suppress food and water intake and induce emesis involve GLP-1 receptors in the hypothalamus and brainstem.
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Affiliation(s)
- Zengbing Lu
- School of Health Sciences, Caritas Institute of Higher Education, Hong Kong SAR, China; School of Biomedical Sciences, Hong Kong SAR, China
| | - Sze Wa Chan
- School of Health Sciences, Caritas Institute of Higher Education, Hong Kong SAR, China.
| | - Longlong Tu
- School of Biomedical Sciences, Hong Kong SAR, China
| | - Man Piu Ngan
- School of Biomedical Sciences, Hong Kong SAR, China
| | - John A Rudd
- School of Biomedical Sciences, Hong Kong SAR, China; Laboratory Animal Services Centre, The Chinese University of Hong Kong, Hong Kong SAR, China
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12
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An alternative pathway for sweet sensation: possible mechanisms and physiological relevance. Pflugers Arch 2020; 472:1667-1691. [PMID: 33030576 DOI: 10.1007/s00424-020-02467-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/14/2020] [Accepted: 09/23/2020] [Indexed: 12/12/2022]
Abstract
Sweet substances are detected by taste-bud cells upon binding to the sweet-taste receptor, a T1R2/T1R3 heterodimeric G protein-coupled receptor. In addition, experiments with mouse models lacking the sweet-taste receptor or its downstream signaling components led to the proposal of a parallel "alternative pathway" that may serve as metabolic sensor and energy regulator. Indeed, these mice showed residual nerve responses and behavioral attraction to sugars and oligosaccharides but not to artificial sweeteners. In analogy to pancreatic β cells, such alternative mechanism, to sense glucose in sweet-sensitive taste cells, might involve glucose transporters and KATP channels. Their activation may induce depolarization-dependent Ca2+ signals and release of GLP-1, which binds to its receptors on intragemmal nerve fibers. Via unknown neuronal and/or endocrine mechanisms, this pathway may contribute to both, behavioral attraction and/or induction of cephalic-phase insulin release upon oral sweet stimulation. Here, we critically review the evidence for a parallel sweet-sensitive pathway, involved signaling mechanisms, neural processing, interactions with endocrine hormonal mechanisms, and its sensitivity to different stimuli. Finally, we propose its physiological role in detecting the energy content of food and preparing for digestion.
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13
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Gorky J, Schwaber J. Conceptualization of a Parasympathetic Endocrine System. Front Neurosci 2019; 13:1008. [PMID: 31607849 PMCID: PMC6767939 DOI: 10.3389/fnins.2019.01008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 09/05/2019] [Indexed: 12/18/2022] Open
Abstract
We here propose a parasympathetic endocrine system (PES) comprised of circulating peptides released from secretory cells in the gut, significantly modulated by vagal projections from the dorsal motor nucleus of the vagus (DMV). While most of these gut peptides mediate well-described satiety and digestive effects that increase parasympathetic control of digestion (Lee et al., 1994; Gutzwiller et al., 1999; Klok et al., 2007), they also have actions that are far-reaching and increase parasympathetic signaling broadly throughout the body. The actions beyond satiety that peptides like somatostatin, cholecystokinin, glucagon-like peptide 1, and vasoactive intestinal peptide have been well-examined, but not in a systematic way. Consideration has been given to the idea that these and other gut-derived peptides are part of an endocrine system has been partially considered (Rehfeld, 2012; Drucker, 2016), but that it is coordinated through parasympathetic control and may act to increase the actions of parasympathetic projections has not been formalized before. Here only gut-derived hormones are included although there are potentially other parasympathetically mediated factors released from other sites like lung and liver (Drucker, 2016). The case for the existence of the PES with the DMV as its integrative controller will be made through examination of an anatomical substrate and evidence of physiological control mechanisms as well as direct examples of PES antagonism of sympathetic signaling in mammals, including humans. The implications for this conceptual understanding of a PES reframe diseases like metabolic syndrome and may help underscore the role of the autonomic nervous system in the associated symptoms.
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Affiliation(s)
- Jonathan Gorky
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - James Schwaber
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University, Philadelphia, PA, United States
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14
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Sun Z, Sun X, Li J, Li Z, Hu Q, Li L, Hao X, Song M, Li C. Using probiotics for type 2 diabetes mellitus intervention: Advances, questions, and potential. Crit Rev Food Sci Nutr 2019; 60:670-683. [PMID: 30632770 DOI: 10.1080/10408398.2018.1547268] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Type 2 diabetes mellitus (T2DM) has become one of the most prevalent diseases on earth and several treatments have been developed. However, the current intervention approaches have not been as effective as expected. One promising supplementary strategy is the use of probiotics through direct or indirect approaches. Probiotics are microbial food cultures conferring health-promoting properties. In this review, we summarized the current theories and mechanisms of T2DM intervention using probiotics and hypothesize that probiotics intervene T2DM during its onsetting, developing, and complicating. For the first time, we comprehensively analyzed T2DM intervention in animal models using both wide-type probiotics in different forms and using recombinant probiotics. Then, probiotic intervention in T2DM patients was reviewed and the main results were compared with that obtained from animal studies. Finally yet importantly, remaining questions that are important such as in which form and in which state, as well as the future potential of probiotic intervention in T2DM were discussed from a perspective of food microbiologists. In conclusion, probiotic intervention in T2DM is promising but there are still many important issues unsolved yet. Critical review of the advances, questions, and potential of probiotic intervention in T2DM promotes the development of this approach for further application in humans.
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Affiliation(s)
- Zhongke Sun
- College of Life Sciences and Agronomy, Zhoukou Normal University, Zhoukou, China.,College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, China
| | - Xuejiao Sun
- College of Life Sciences and Agronomy, Zhoukou Normal University, Zhoukou, China.,College of Life Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Juan Li
- College of Life Sciences and Agronomy, Zhoukou Normal University, Zhoukou, China
| | - Zhaoyang Li
- College of Life Sciences and Agronomy, Zhoukou Normal University, Zhoukou, China
| | - Qingwei Hu
- Zhoukou Maternal and Child Health Care Hospital, Zhoukou, China
| | - Lili Li
- College of Life Sciences and Agronomy, Zhoukou Normal University, Zhoukou, China
| | - Xinqi Hao
- College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, China
| | - Maoping Song
- College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou, China
| | - Chengwei Li
- College of Life Sciences and Agronomy, Zhoukou Normal University, Zhoukou, China.,College of Life Sciences, Henan Institute of Science and Technology, Xinxiang, China
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15
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Batista AF, Forny-Germano L, Clarke JR, Lyra E Silva NM, Brito-Moreira J, Boehnke SE, Winterborn A, Coe BC, Lablans A, Vital JF, Marques SA, Martinez AM, Gralle M, Holscher C, Klein WL, Houzel JC, Ferreira ST, Munoz DP, De Felice FG. The diabetes drug liraglutide reverses cognitive impairment in mice and attenuates insulin receptor and synaptic pathology in a non-human primate model of Alzheimer's disease. J Pathol 2018; 245:85-100. [PMID: 29435980 PMCID: PMC5947670 DOI: 10.1002/path.5056] [Citation(s) in RCA: 160] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 01/13/2018] [Accepted: 02/05/2018] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease (AD) is a devastating neurological disorder that still lacks an effective treatment, and this has stimulated an intense pursuit of disease-modifying therapeutics. Given the increasingly recognized link between AD and defective brain insulin signaling, we investigated the actions of liraglutide, a glucagon-like peptide-1 (GLP-1) analog marketed for treatment of type 2 diabetes, in experimental models of AD. Insulin receptor pathology is an important feature of AD brains that impairs the neuroprotective actions of central insulin signaling. Here, we show that liraglutide prevented the loss of brain insulin receptors and synapses, and reversed memory impairment induced by AD-linked amyloid-β oligomers (AβOs) in mice. Using hippocampal neuronal cultures, we determined that the mechanism of neuroprotection by liraglutide involves activation of the PKA signaling pathway. Infusion of AβOs into the lateral cerebral ventricle of non-human primates (NHPs) led to marked loss of insulin receptors and synapses in brain regions related to memory. Systemic treatment of NHPs with liraglutide provided partial protection, decreasing AD-related insulin receptor, synaptic, and tau pathology in specific brain regions. Synapse damage and elimination are amongst the earliest known pathological changes and the best correlates of memory impairment in AD. The results illuminate mechanisms of neuroprotection by liraglutide, and indicate that GLP-1 receptor activation may be harnessed to protect brain insulin receptors and synapses in AD. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Andre F Batista
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leticia Forny-Germano
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Julia R Clarke
- School of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Natalia M Lyra E Silva
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Jordano Brito-Moreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Susan E Boehnke
- Centre for Neuroscience Studies, Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | | | - Brian C Coe
- Centre for Neuroscience Studies, Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Ann Lablans
- Centre for Neuroscience Studies, Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Juliana F Vital
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Suelen A Marques
- Departament of Neurobiology, Fluminense Federal University, Niteroi, Brazil
| | - Ana Mb Martinez
- Department of Pathology, Faculty of Medicine, Hospital Universitário Clementino Fraga Filho, UFRJ, Rio de Janeiro, Brazil
| | - Matthias Gralle
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Christian Holscher
- Division of Biomed and Life Sciences, Faculty of Health and Medicine Lancaster University, Lancaster, UK
| | - William L Klein
- Department of Neurobiology, Northwestern University, Evanston, Illinois, USA
| | - Jean-Christophe Houzel
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Sergio T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Douglas P Munoz
- Centre for Neuroscience Studies, Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Centre for Neuroscience Studies, Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
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16
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Burmeister MA, Brown JD, Ayala JE, Stoffers DA, Sandoval DA, Seeley RJ, Ayala JE. The glucagon-like peptide-1 receptor in the ventromedial hypothalamus reduces short-term food intake in male mice by regulating nutrient sensor activity. Am J Physiol Endocrinol Metab 2017; 313:E651-E662. [PMID: 28811293 PMCID: PMC6109646 DOI: 10.1152/ajpendo.00113.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 07/27/2017] [Accepted: 08/10/2017] [Indexed: 12/25/2022]
Abstract
Pharmacological activation of the glucagon-like peptide-1 receptor (GLP-1R) in the ventromedial hypothalamus (VMH) reduces food intake. Here, we assessed whether suppression of food intake by GLP-1R agonists (GLP-1RA) in this region is dependent on AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR). We found that pharmacological inhibition of glycolysis, and thus activation of AMPK, in the VMH attenuates the anorectic effect of the GLP-1R agonist exendin-4 (Ex4), indicating that glucose metabolism and inhibition of AMPK are both required for this effect. Furthermore, we found that Ex4-mediated anorexia in the VMH involved mTOR but not acetyl-CoA carboxylase, two downstream targets of AMPK. We support this by showing that Ex4 activates mTOR signaling in the VMH and Chinese hamster ovary (CHO)-K1 cells. In contrast to the clear acute pharmacological impact of the these receptors on food intake, knockdown of the VMH Glp1r conferred no changes in energy balance in either chow- or high-fat-diet-fed mice, and the acute anorectic and glucose tolerance effects of peripherally dosed GLP-1RA were preserved. These results show that the VMH GLP-1R regulates food intake by engaging key nutrient sensors but is dispensable for the effects of GLP-1RA on nutrient homeostasis.
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Affiliation(s)
- Melissa A Burmeister
- Integrative Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida;
| | - Jacob D Brown
- Integrative Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida
| | - Jennifer E Ayala
- Integrative Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida
| | - Doris A Stoffers
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Darleen A Sandoval
- Department of Surgery, University of Michigan Health System, Ann Arbor, Michigan
| | - Randy J Seeley
- Department of Surgery, University of Michigan Health System, Ann Arbor, Michigan
| | - Julio E Ayala
- Integrative Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida
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17
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Mertens KL, Kalsbeek A, Soeters MR, Eggink HM. Bile Acid Signaling Pathways from the Enterohepatic Circulation to the Central Nervous System. Front Neurosci 2017; 11:617. [PMID: 29163019 PMCID: PMC5681992 DOI: 10.3389/fnins.2017.00617] [Citation(s) in RCA: 170] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/23/2017] [Indexed: 12/14/2022] Open
Abstract
Bile acids are best known as detergents involved in the digestion of lipids. In addition, new data in the last decade have shown that bile acids also function as gut hormones capable of influencing metabolic processes via receptors such as FXR (farnesoid X receptor) and TGR5 (Takeda G protein-coupled receptor 5). These effects of bile acids are not restricted to the gastrointestinal tract, but can affect different tissues throughout the organism. It is still unclear whether these effects also involve signaling of bile acids to the central nervous system (CNS). Bile acid signaling to the CNS encompasses both direct and indirect pathways. Bile acids can act directly in the brain via central FXR and TGR5 signaling. In addition, there are two indirect pathways that involve intermediate agents released upon interaction with bile acids receptors in the gut. Activation of intestinal FXR and TGR5 receptors can result in the release of fibroblast growth factor 19 (FGF19) and glucagon-like peptide 1 (GLP-1), both capable of signaling to the CNS. We conclude that when plasma bile acids levels are high all three pathways may contribute in signal transmission to the CNS. However, under normal physiological circumstances, the indirect pathway involving GLP-1 may evoke the most substantial effect in the brain.
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Affiliation(s)
- Kim L Mertens
- Master's Program in Biomedical Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Laboratory of Endocrinology, Department Clinical Chemistry, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands.,Department of Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
| | - Maarten R Soeters
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Hannah M Eggink
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Department of Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
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18
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Gaykema RP, Newmyer BA, Ottolini M, Raje V, Warthen DM, Lambeth PS, Niccum M, Yao T, Huang Y, Schulman IG, Harris TE, Patel MK, Williams KW, Scott MM. Activation of murine pre-proglucagon-producing neurons reduces food intake and body weight. J Clin Invest 2017; 127:1031-1045. [PMID: 28218622 DOI: 10.1172/jci81335] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 12/30/2016] [Indexed: 12/14/2022] Open
Abstract
Peptides derived from pre-proglucagon (GCG peptides) act in both the periphery and the CNS to change food intake, glucose homeostasis, and metabolic rate while playing a role in anxiety behaviors and physiological responses to stress. Although the actions of GCG peptides produced in the gut and pancreas are well described, the role of glutamatergic GGC peptide-secreting hindbrain neurons in regulating metabolic homeostasis has not been investigated. Here, we have shown that chemogenetic stimulation of GCG-producing neurons reduces metabolic rate and food intake in fed and fasted states and suppresses glucose production without an effect on glucose uptake. Stimulation of GCG neurons had no effect on corticosterone secretion, body weight, or conditioned taste aversion. In the diet-induced obese state, the effects of GCG neuronal stimulation on gluconeogenesis were lost, while the food intake-lowering effects remained, resulting in reductions in body weight and adiposity. Our work suggests that GCG peptide-expressing neurons can alter feeding, metabolic rate, and glucose production independent of their effects on hypothalamic pituitary-adrenal (HPA) axis activation, aversive conditioning, or insulin secretion. We conclude that GCG neurons likely stimulate separate populations of downstream cells to produce a change in food intake and glucose homeostasis and that these effects depend on the metabolic state of the animal.
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19
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João AL, Reis F, Fernandes R. The incretin system ABCs in obesity and diabetes - novel therapeutic strategies for weight loss and beyond. Obes Rev 2016; 17:553-72. [PMID: 27125902 DOI: 10.1111/obr.12421] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/21/2016] [Accepted: 03/28/2016] [Indexed: 02/06/2023]
Abstract
Incretins are gastrointestinal-derived hormones released in response to a meal playing a key role in the regulation of postprandial secretion of insulin (incretin effect) and glucagon by the pancreas. Both incretins, glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 (GLP-1), have several other actions by peripheral and central mechanisms. GLP-1 regulates body weight by inhibiting appetite and delaying gastric, emptying actions that are dependent on central nervous system GLP-1 receptor activation. Several other hormones and gut peptides, including leptin and ghrelin, interact with GLP-1 to modulate appetite. GLP-1 is rapidly degraded by the multifunctional enzyme dipeptidyl peptidase-4 (DPP-4). DPP-4 is involved in adipose tissue inflammation, which is associated with insulin resistance and diabetes progression, being a common pathophysiological mechanism in obesity-related complications. Furthermore, the incretin system appears to provide the basis for understanding the high weight loss efficacy of bariatric surgery, a widely used treatment for obesity, often in association with diabetes. The present review brings together new insights into obesity pathogenesis, integrating GLP-1 and DPP-4 in the complex interplay between obesity and inflammation, namely, in diabetic patients. This in turn will provide the basis for novel incretin-based therapeutic strategies for obesity and diabetes with promising benefits in addition to weight loss. © 2016 World Obesity.
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Affiliation(s)
- A L João
- Laboratory of Pharmacology and Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine and Center for Neuroscience and Cell Biology - Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Research Consortium, University of Coimbra, Coimbra, Portugal
| | - F Reis
- Laboratory of Pharmacology and Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine and Center for Neuroscience and Cell Biology - Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Research Consortium, University of Coimbra, Coimbra, Portugal
| | - R Fernandes
- Laboratory of Pharmacology and Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine and Center for Neuroscience and Cell Biology - Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Research Consortium, University of Coimbra, Coimbra, Portugal
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20
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Tudurí E, Beiroa D, Porteiro B, López M, Diéguez C, Nogueiras R. Acute but not chronic activation of brain glucagon-like peptide-1 receptors enhances glucose-stimulated insulin secretion in mice. Diabetes Obes Metab 2015; 17:789-99. [PMID: 25962313 DOI: 10.1111/dom.12488] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/24/2015] [Accepted: 05/03/2015] [Indexed: 01/15/2023]
Abstract
AIM To investigate the role of brain glucagon-like peptide-1 (GLP-1) in pancreatic β-cell function. METHODS To determine the role of brain GLP-1 receptor (GLP-1R) on β-cell function, we administered intracerebroventricular (i.c.v.) infusions of GLP-1 or the specific GLP-1 antagonist exendin-9 (Ex-9), in both an acute and a chronic setting. RESULTS We observed that acute i.c.v. GLP-1 infusion potentiates glucose-stimulated insulin secretion (GSIS) and improves glucose tolerance, whereas central GLP-1R blockade with Ex-9 impaired glucose excursion after a glucose load. Sustained activation of central nervous system GLP-1R, however, did not produce any effect on either GSIS or glucose tolerance. Similarly, ex vivo GSIS performed in islets from mice chronically infused with i.c.v. GLP-1 resulted in no differences compared with controls. In addition, in mice fed a high-fat diet we observed that acute i.c.v. GLP-1 infusion improved glucose tolerance without changes in GSIS, while chronic GLP-1R activation had no effect on glucose homeostasis. CONCLUSIONS Our results indicate that, under non-clamped conditions, brain GLP-1 plays a functional neuroendocrine role in the acute regulation of glucose homeostasis in both lean and obese rodents.
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Affiliation(s)
- E Tudurí
- Instituto de Investigaciones Sanitarias, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición, Santiago de Compostela, Spain
| | - D Beiroa
- Instituto de Investigaciones Sanitarias, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición, Santiago de Compostela, Spain
- Department of Physiology, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - B Porteiro
- Instituto de Investigaciones Sanitarias, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición, Santiago de Compostela, Spain
- Department of Physiology, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - M López
- Instituto de Investigaciones Sanitarias, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición, Santiago de Compostela, Spain
- Department of Physiology, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - C Diéguez
- Instituto de Investigaciones Sanitarias, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición, Santiago de Compostela, Spain
- Department of Physiology, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - R Nogueiras
- Instituto de Investigaciones Sanitarias, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición, Santiago de Compostela, Spain
- Department of Physiology, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
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Farr S, Baker C, Naples M, Taher J, Iqbal J, Hussain M, Adeli K. Central Nervous System Regulation of Intestinal Lipoprotein Metabolism by Glucagon-Like Peptide-1 via a Brain–Gut Axis. Arterioscler Thromb Vasc Biol 2015; 35:1092-100. [DOI: 10.1161/atvbaha.114.304873] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/28/2015] [Indexed: 12/29/2022]
Affiliation(s)
- Sarah Farr
- From the Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada (S.F., J.T., K.A.); Molecular Structure and Function Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (S.F., C.B., M.N., J.T., K.A.); and Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY (J.I., M.H.)
| | - Christopher Baker
- From the Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada (S.F., J.T., K.A.); Molecular Structure and Function Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (S.F., C.B., M.N., J.T., K.A.); and Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY (J.I., M.H.)
| | - Mark Naples
- From the Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada (S.F., J.T., K.A.); Molecular Structure and Function Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (S.F., C.B., M.N., J.T., K.A.); and Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY (J.I., M.H.)
| | - Jennifer Taher
- From the Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada (S.F., J.T., K.A.); Molecular Structure and Function Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (S.F., C.B., M.N., J.T., K.A.); and Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY (J.I., M.H.)
| | - Jahangir Iqbal
- From the Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada (S.F., J.T., K.A.); Molecular Structure and Function Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (S.F., C.B., M.N., J.T., K.A.); and Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY (J.I., M.H.)
| | - Mahmood Hussain
- From the Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada (S.F., J.T., K.A.); Molecular Structure and Function Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (S.F., C.B., M.N., J.T., K.A.); and Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY (J.I., M.H.)
| | - Khosrow Adeli
- From the Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada (S.F., J.T., K.A.); Molecular Structure and Function Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (S.F., C.B., M.N., J.T., K.A.); and Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY (J.I., M.H.)
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Abstract
Type 2 diabetes is a chronic disease that can be treated with pharmacologic and/or lifestyle interventions, but in most cases it does not get cured. One of the few interventions, however, that can remit diabetes is the Roux-en-Y gastric bypass (RYGB) surgery. Approximately 63 % of patients undergoing RYGB surgery experience diabetes remission, but the underlying mechanisms are poorly understood. Some studies implicate enterohepatic pathways with bile acids, fibroblast growth factor 19 (FGF19), and glucagon-like peptide 1 (GLP-1) being the primary components. Here, we discuss these enterohepatic changes and highlight the roles of bile acids, FGF19, and GLP-1 in diabetes remission. We also describe how we can now actually predict, prior to surgery, the probability for remitting diabetes after RYGB surgery by using the DiaRem score. Deeper understanding of the mechanisms of diabetes remission by RYGB surgery could provide the basis for developing more effective interventions for curing the disease.
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Affiliation(s)
- George Argyropoulos
- Institute of Obesity, Geisinger Health System, 100 North Academy Avenue, Danville, PA, 17822, USA,
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Sisley S, Gutierrez-Aguilar R, Scott M, D'Alessio DA, Sandoval DA, Seeley RJ. Neuronal GLP1R mediates liraglutide's anorectic but not glucose-lowering effect. J Clin Invest 2014; 124:2456-63. [PMID: 24762441 DOI: 10.1172/jci72434] [Citation(s) in RCA: 274] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Glucose control and weight loss are cornerstones of type 2 diabetes treatment. Currently, only glucagon-like peptide-1 (GLP1) analogs are able to achieve both weight loss and glucose tolerance. Both glucose and body weight are regulated by the brain, which contains GLP1 receptors (GLP1R). Even though the brain is poised to mediate the effects of GLP1 analogs, it remains unclear whether the glucose- and body weight-lowering effects of long-acting GLP1R agonists are via direct action on CNS GLP1R or the result of downstream activation of afferent neuronal GLP1R. We generated mice with either neuronal or visceral nerve-specific deletion of Glp1r and then administered liraglutide, a long-acting GLP1R agonist. We found that neither reduction of GLP1R in the CNS nor in the visceral nerves resulted in alterations in body weight or food intake in animals fed normal chow or a high-fat diet. Liraglutide treatment provided beneficial glucose-lowering effects in both chow- and high-fat-fed mice lacking GLP1R in the CNS or visceral nerves; however, liraglutide was ineffective at altering food intake, body weight, or causing a conditioned taste aversion in mice lacking neuronal GLP1R. These data indicate that neuronal GLP1Rs mediate body weight and anorectic effects of liraglutide, but are not required for glucose-lowering effects.
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Nadkarni P, Chepurny OG, Holz GG. Regulation of glucose homeostasis by GLP-1. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014. [PMID: 24373234 DOI: 10.1016/b978-0-12-800101-1.00002-8.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/01/2022]
Abstract
Glucagon-like peptide-1(7-36)amide (GLP-1) is a secreted peptide that acts as a key determinant of blood glucose homeostasis by virtue of its abilities to slow gastric emptying, to enhance pancreatic insulin secretion, and to suppress pancreatic glucagon secretion. GLP-1 is secreted from L cells of the gastrointestinal mucosa in response to a meal, and the blood glucose-lowering action of GLP-1 is terminated due to its enzymatic degradation by dipeptidyl-peptidase-IV (DPP-IV). Released GLP-1 activates enteric and autonomic reflexes while also circulating as an incretin hormone to control endocrine pancreas function. The GLP-1 receptor (GLP-1R) is a G protein-coupled receptor that is activated directly or indirectly by blood glucose-lowering agents currently in use for the treatment of type 2 diabetes mellitus (T2DM). These therapeutic agents include GLP-1R agonists (exenatide, liraglutide, lixisenatide, albiglutide, dulaglutide, and langlenatide) and DPP-IV inhibitors (sitagliptin, vildagliptin, saxagliptin, linagliptin, and alogliptin). Investigational agents for use in the treatment of T2DM include GPR119 and GPR40 receptor agonists that stimulate the release of GLP-1 from L cells. Summarized here is the role of GLP-1 to control blood glucose homeostasis, with special emphasis on the advantages and limitations of GLP-1-based therapeutics.
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Affiliation(s)
- Prashant Nadkarni
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Joslin Diabetes Center, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - Oleg G Chepurny
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - George G Holz
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Department of Pharmacology, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA.
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25
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Nadkarni P, Chepurny OG, Holz GG. Regulation of glucose homeostasis by GLP-1. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 121:23-65. [PMID: 24373234 DOI: 10.1016/b978-0-12-800101-1.00002-8] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glucagon-like peptide-1(7-36)amide (GLP-1) is a secreted peptide that acts as a key determinant of blood glucose homeostasis by virtue of its abilities to slow gastric emptying, to enhance pancreatic insulin secretion, and to suppress pancreatic glucagon secretion. GLP-1 is secreted from L cells of the gastrointestinal mucosa in response to a meal, and the blood glucose-lowering action of GLP-1 is terminated due to its enzymatic degradation by dipeptidyl-peptidase-IV (DPP-IV). Released GLP-1 activates enteric and autonomic reflexes while also circulating as an incretin hormone to control endocrine pancreas function. The GLP-1 receptor (GLP-1R) is a G protein-coupled receptor that is activated directly or indirectly by blood glucose-lowering agents currently in use for the treatment of type 2 diabetes mellitus (T2DM). These therapeutic agents include GLP-1R agonists (exenatide, liraglutide, lixisenatide, albiglutide, dulaglutide, and langlenatide) and DPP-IV inhibitors (sitagliptin, vildagliptin, saxagliptin, linagliptin, and alogliptin). Investigational agents for use in the treatment of T2DM include GPR119 and GPR40 receptor agonists that stimulate the release of GLP-1 from L cells. Summarized here is the role of GLP-1 to control blood glucose homeostasis, with special emphasis on the advantages and limitations of GLP-1-based therapeutics.
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Affiliation(s)
- Prashant Nadkarni
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Joslin Diabetes Center, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - Oleg G Chepurny
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - George G Holz
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Department of Pharmacology, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA.
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26
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Mokadem M, Zechner JF, Margolskee RF, Drucker DJ, Aguirre V. Effects of Roux-en-Y gastric bypass on energy and glucose homeostasis are preserved in two mouse models of functional glucagon-like peptide-1 deficiency. Mol Metab 2013; 3:191-201. [PMID: 24634822 DOI: 10.1016/j.molmet.2013.11.010] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 11/21/2013] [Accepted: 11/25/2013] [Indexed: 12/13/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) secretion is greatly enhanced after Roux-en-Y gastric bypass (RYGB). While intact GLP-1exerts its metabolic effects via the classical GLP-1 receptor (GLP-1R), proteolytic processing of circulating GLP-1 yields metabolites such as GLP-1(9-36)amide/GLP-1(28-36)amide, that exert similar effects independent of the classical GLP-1R. We investigated the hypothesis that GLP-1, acting via these metabolites or through its known receptor, is required for the beneficial effects of RYGB using two models of functional GLP-1 deficiency - α-gustducin-deficient (α-Gust (-/-)) mice, which exhibit attenuated nutrient-stimulated GLP-1 secretion, and GLP-1R-deficient mice. We show that the effect of RYGB to enhance glucose-stimulated GLP-1 secretion was greatly attenuated in α-Gust (-/-) mice. In both genetic models, RYGB reduced body weight and improved glucose homeostasis to levels observed in lean control mice. Therefore, GLP-1, acting through its classical GLP-1R or its bioactive metabolites, does not seem to be involved in the effects of RYGB on body weight and glucose homeostasis.
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Affiliation(s)
- Mohamad Mokadem
- Center for Hypothalamic Research, Division of Digestive and Liver Diseases, Department of Internal Medicine, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Juliet F Zechner
- Center for Hypothalamic Research, Division of Digestive and Liver Diseases, Department of Internal Medicine, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Robert F Margolskee
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Daniel J Drucker
- Department of Medicine, Mt. Sinai Hospital, Samuel Lunenfeld Research Institute, University of Toronto, 600 University Avenue, Toronto, Ontario, Canada M5G 1X5
| | - Vincent Aguirre
- Center for Hypothalamic Research, Division of Digestive and Liver Diseases, Department of Internal Medicine, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
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Diepenbroek C, Serlie MJ, Fliers E, Kalsbeek A, la Fleur SE. Brain areas and pathways in the regulation of glucose metabolism. Biofactors 2013; 39:505-13. [PMID: 23913677 DOI: 10.1002/biof.1123] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/28/2013] [Indexed: 11/11/2022]
Abstract
Glucose is the most important source of fuel for the brain and its concentration must be kept within strict boundaries to ensure the organism's optimal fitness. To maintain glucose homeostasis, an optimal balance between glucose uptake and glucose output is required. Besides managing acute changes in plasma glucose concentrations, the brain controls a daily rhythm in glucose concentrations. The various nuclei within the hypothalamus that are involved in the control of both these processes are well known. However, novel studies indicate an additional role for brain areas that are originally appreciated in other processes than glucose metabolism. Therefore, besides the classic hypothalamic pathways, we will review cortico-limbic brain areas and their role in glucose metabolism.
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Affiliation(s)
- Charlene Diepenbroek
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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28
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Ghosal S, Myers B, Herman JP. Role of central glucagon-like peptide-1 in stress regulation. Physiol Behav 2013; 122:201-7. [PMID: 23623992 DOI: 10.1016/j.physbeh.2013.04.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 03/20/2013] [Accepted: 04/16/2013] [Indexed: 01/12/2023]
Abstract
Glucagon-like peptide 1 (GLP-1) is best known as an incretin hormone, secreted from L cells in the intestine in response to nutrient ingestion to stimulate glucose-dependent insulin secretion. However, GLP-1 is also expressed in neurons, and plays a major role in regulation of homeostatic function within the central nervous system (CNS). This review summarizes our current state of knowledge on the role GLP-1 plays in neural coordination of the organismal stress response. In the brain, the primary locus of GLP-1 production is in the caudal nucleus of the solitary tract (NTS) and the ventrolateral medulla of the hindbrain. GLP-1 immunoreactive fibers directly innervate hypophysiotrophic corticotropin-releasing hormone (CRH) neurons in the hypothalamic paraventricular nucleus (PVN), placing GLP-1 in prime position to integrate hypothalamo-pituitary-adrenocortical responses. Exogenous central GLP-1 activates HPA axis stress responses, and responses to a variety of stressors can be blocked by a GLP-1 receptor (GLP-1R) antagonist, confirming an excitatory role in glucocorticoid secretion. In addition, central infusion of GLP-1R agonist increases heart rate and blood pressure, and activates hypothalamic and brainstem neurons innervating sympathetic preganglionic neurons, suggesting a sympathoexcitatory role of GLP-1 in the CNS. Bioavailability of preproglucagon (PPG) mRNA and GLP-1 peptide is reduced by exogenous or endogenous glucocorticoid secretion, perhaps as a mechanism to reduce GLP-1-mediated stress excitation. Altogether, the data suggest that GLP-1 plays a key role in activation of stress responses, which may be connected with its role in central regulation of energy homeostasis.
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Affiliation(s)
- Sriparna Ghosal
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Reading Campus, OH 45237-0506, USA.
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29
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Zsombok A. Autonomic control and bariatric procedures. Auton Neurosci 2013; 177:81-6. [PMID: 23538033 DOI: 10.1016/j.autneu.2013.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 10/10/2012] [Accepted: 03/01/2013] [Indexed: 12/12/2022]
Abstract
The sudden improvement of metabolic profile and the remission of type 2 diabetes after bariatric surgery, well before weight loss, raise important new questions regarding glycemic control. Currently, various types of bariatric procedures target type 2 diabetes in obese and non-obese patients. Nevertheless, the origin of the dramatic metabolic improvements, including glucose homeostasis, is poorly understood, and the role of the gastrointestinal (GI) tract remains relatively speculative, as well as why these procedures are variably effective. One neglected explanation is that such interventions disrupt neural networks mediating GI-brain communication and could alter the autonomic output to the visceral organs, including the liver. Incretins, e.g., glucagon-like peptide 1 (GLP-1), have major influence on the central nervous system. Moreover, the level of GLP-1 is observed to significantly increase after bariatric surgery and could be a key factor in the weight-independent, anti-diabetic effect. Therefore, this review will evaluate the effect of GLP-1 on the central nervous system, with emphasis on the cellular effects of GLP-1, and will provide an overview of the autonomic control of the liver.
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Affiliation(s)
- Andrea Zsombok
- Department of Physiology, Endocrinology Section, Tulane University, School of Medicine, 1430 Tulane Ave., SL39, New Orleans, LA 70112, United States; Department of Medicine, Endocrinology Section, Tulane University, School of Medicine, 1430 Tulane Ave., SL39, New Orleans, LA 70112, United States.
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Yang SB, Tien AC, Boddupalli G, Xu AW, Jan YN, Jan LY. Rapamycin ameliorates age-dependent obesity associated with increased mTOR signaling in hypothalamic POMC neurons. Neuron 2012; 75:425-36. [PMID: 22884327 DOI: 10.1016/j.neuron.2012.03.043] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2012] [Indexed: 01/08/2023]
Abstract
VIDEO ABSTRACT The prevalence of obesity in older people is the leading cause of metabolic syndromes. Central neurons serving as homeostatic sensors for body-weight control include hypothalamic neurons that express pro-opiomelanocortin (POMC) or neuropeptide-Y (NPY) and agouti-related protein (AgRP). Here, we report an age-dependent increase of mammalian target of rapamycin (mTOR) signaling in POMC neurons that elevates the ATP-sensitive potassium (K(ATP)) channel activity cell-autonomously to silence POMC neurons. Systemic or intracerebral administration of the mTOR inhibitor rapamycin causes weight loss in old mice. Intracerebral rapamycin infusion into old mice enhances the excitability and neurite projection of POMC neurons, thereby causing a reduction of food intake and body weight. Conversely, young mice lacking the mTOR-negative regulator TSC1 in POMC neurons, but not those lacking TSC1 in NPY/AgRP neurons, were obese. Our study reveals that an increase in mTOR signaling in hypothalamic POMC neurons contributes to age-dependent obesity.
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Affiliation(s)
- Shi-Bing Yang
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
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Mori Y, Taniguchi Y, Matsuura K, Sezaki K, Yokoyama J, Utsunomiya K. Effects of sitagliptin on 24-h glycemic changes in Japanese patients with type 2 diabetes assessed using continuous glucose monitoring. Diabetes Technol Ther 2011; 13:699-703. [PMID: 21504334 DOI: 10.1089/dia.2011.0025] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND This study was performed to examine the efficacy of sitagliptin, a dipeptidyl peptidase-4 inhibitor, in Japanese patients with type 2 diabetes using continuous glucose monitoring (CGM) of 24-h glycemic changes. SUBJECTS AND METHODS The study was a prospective open-label pilot study in patients with type 2 diabetes who were admitted to our hospital and treated with sitagliptin alone or concomitantly with another oral hypoglycemic drug. CGM was performed for 2 days before sitagliptin administration and for another 2 days after administration. The average 24-h blood glucose level, SD of the 24-h blood glucose level, 24-h glycemic fluctuation range, mean amplitude of glycemic excursions (MAGE), and hyperglycemic and hypoglycemic time periods were compared before and after administration. RESULTS Sitagliptin administration alone and with a concomitant drug decreased the average 24-h blood glucose level, SD of the 24-h blood glucose level, 24-h glycemic fluctuation range, MAGE, and hyperglycemic time, compared with these parameters before administration. There were significant correlations between the average 24-h blood glucose level before administration and the decrease in the average 24-h blood glucose level after administration and between MAGE before administration and the decrease in MAGE after administration. CONCLUSIONS Sitagliptin decreased the average glycemic level and also improved 24-h glycemic fluctuation, including postprandial hyperglycemia.
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Affiliation(s)
- Yutaka Mori
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Jikei University Daisan Hospital, Tokyo, Japan.
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Polakof S, Míguez JM, Soengas JL. Evidence for a gut-brain axis used by glucagon-like peptide-1 to elicit hyperglycaemia in fish. J Neuroendocrinol 2011; 23:508-18. [PMID: 21564347 DOI: 10.1111/j.1365-2826.2011.02137.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In mammals, glucagon-like peptide-1 (GLP-1) produces changes in glucose and energy homeostasis through a gut-pancreas-brain axis. In fish, the effects of GLP-1 are opposed to those described in other vertebrates, such as stimulation of hyperglycaemia and the lack of an effect of incretin. In the present study conducted in a teleost fish such as the rainbow trout, we present evidence of a gut-brain axis used by GLP-1 to exert its actions on glucose and energy homeostasis. We have assessed the effects of GLP-1 on glucose metabolism in the liver as well as the glucose-sensing potential in the hypothalamus and hindbrain. We confirm that peripheral GLP-1 administration elicits sustained hyperglycaemia, whereas, for the first time in a vertebrate species, we report that central GLP-1 treatment increases plasma glucose levels. We have observed (using capsaicin) that at least part of the action of GLP-1 on glucose homeostasis was mediated by vagal and splanchnic afferents. GLP-1 has a direct effect in parameters involved in glucose sensing in the hindbrain, whereas, in the hypothalamus, changes occurred indirectly through hyperglycaemia. Moreover, in the hindbrain, GLP-1 altered the expression of peptides involved in the control of food intake. We have elaborated a model for the actions of GLP-1 in fish in which this peptide uses a mammalian-like ancestral gut-brain axis to elicit the regulation of glucose homeostasis in different manner than the model described in mammals. Finally, it is worth noting that the hyperglycaemia induced by this peptide and the lack of incretin function could be related to the glucose intolerance observed in carnivorous teleost fish species such as the rainbow trout.
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Affiliation(s)
- S Polakof
- Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, Vigo, Spain.
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Dankel SN, Staalesen V, Bjørndal B, Berge RK, Mellgren G, Burri L. Tissue-specific effects of bariatric surgery including mitochondrial function. J Obes 2011; 2011:435245. [PMID: 21274278 PMCID: PMC3025372 DOI: 10.1155/2011/435245] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 12/14/2010] [Indexed: 12/25/2022] Open
Abstract
A better understanding of the molecular links between obesity and disease is potentially of great benefit for society. In this paper we discuss proposed mechanisms whereby bariatric surgery improves metabolic health, including acute effects on glucose metabolism and long-term effects on metabolic tissues (adipose tissue, skeletal muscle, and liver) and mitochondrial function. More short-term randomized controlled trials should be performed that include simultaneous measurement of metabolic parameters in different tissues, such as tissue gene expression, protein profile, and lipid content. By directly comparing different surgical procedures using a wider array of metabolic parameters, one may further unravel the mechanisms of aberrant metabolic regulation in obesity and related disorders.
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Affiliation(s)
- Simon N. Dankel
- Institute of Medicine, Haukeland University Hospital, University of Bergen, 5021 Bergen, Norway
- Hormone Laboratory, Haukeland University Hospital, 5021 Bergen, Norway
| | - Vidar Staalesen
- Institute of Medicine, Haukeland University Hospital, University of Bergen, 5021 Bergen, Norway
| | - Bodil Bjørndal
- Institute of Medicine, Haukeland University Hospital, University of Bergen, 5021 Bergen, Norway
| | - Rolf K. Berge
- Institute of Medicine, Haukeland University Hospital, University of Bergen, 5021 Bergen, Norway
| | - Gunnar Mellgren
- Institute of Medicine, Haukeland University Hospital, University of Bergen, 5021 Bergen, Norway
- Hormone Laboratory, Haukeland University Hospital, 5021 Bergen, Norway
- *Gunnar Mellgren:
| | - Lena Burri
- Institute of Medicine, Haukeland University Hospital, University of Bergen, 5021 Bergen, Norway
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Nogueiras R, López M, Diéguez C. Regulation of lipid metabolism by energy availability: a role for the central nervous system. Obes Rev 2010; 11:185-201. [PMID: 19845870 DOI: 10.1111/j.1467-789x.2009.00669.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The central nervous system (CNS) is crucial in the regulation of energy homeostasis. Many neuroanatomical studies have shown that the white adipose tissue (WAT) is innervated by the sympathetic nervous system, which plays a critical role in adipocyte lipid metabolism. Therefore, there are currently numerous reports indicating that signals from the CNS control the amount of fat by modulating the storage or oxidation of fatty acids. Importantly, some CNS pathways regulate adipocyte metabolism independently of food intake, suggesting that some signals possess alternative mechanisms to regulate energy homeostasis. In this review, we mainly focus on how neuronal circuits within the hypothalamus, such as leptin- ghrelin-and resistin-responsive neurons, as well as melanocortins, neuropeptide Y, and the cannabinoid system exert their actions on lipid metabolism in peripheral tissues such as WAT, liver or muscle. Dissecting the complicated interactions between peripheral signals and neuronal circuits regulating lipid metabolism might open new avenues for the development of new therapies preventing and treating obesity and its associated cardiometabolic sequelae.
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Affiliation(s)
- R Nogueiras
- Department of Physiology, School of Medicine-Instituto de Investigación Sanitaria (IDIS), University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
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Yi CX, la Fleur SE, Fliers E, Kalsbeek A. The role of the autonomic nervous liver innervation in the control of energy metabolism. Biochim Biophys Acta Mol Basis Dis 2010; 1802:416-31. [PMID: 20060897 DOI: 10.1016/j.bbadis.2010.01.006] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 12/04/2009] [Accepted: 01/05/2010] [Indexed: 01/13/2023]
Abstract
Despite a longstanding research interest ever since the early work by Claude Bernard, the functional significance of autonomic liver innervation, either sympathetic or parasympathetic, is still ill defined. This scarcity of information not only holds for the brain control of hepatic metabolism, but also for the metabolic sensing function of the liver and the way in which this metabolic information from the liver affects the brain. Clinical information from the bedside suggests that successful human liver transplantation (implying a complete autonomic liver denervation) causes no life threatening metabolic derangements, at least in the absence of severe metabolic challenges such as hypoglycemia. However, from the benchside, data are accumulating that interference with the neuronal brain-liver connection does cause pronounced changes in liver metabolism. This review provides an extensive overview on how metabolic information is sensed by the liver, and how this information is processed via neuronal pathways to the brain. With this information the brain controls liver metabolism and that of other organs and tissues. We will pay special attention to the hypothalamic pathways involved in these liver-brain-liver circuits. At this stage, we still do not know the final destination and processing of the metabolic information that is transferred from the liver to the brain. On the other hand, in recent years, there has been a considerable increase in the understanding which brain areas are involved in the control of liver metabolism via its autonomic innervation. However, in view of the ever rising prevalence of type 2 diabetes, this potentially highly relevant knowledge is still by far too limited. Thus the autonomic innervation of the liver and its role in the control of metabolism needs our continued and devoted attention.
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Affiliation(s)
- Chun-Xia Yi
- Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
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McIntosh CHS, Widenmaier S, Kim SJ. Pleiotropic actions of the incretin hormones. VITAMINS AND HORMONES 2010; 84:21-79. [PMID: 21094896 DOI: 10.1016/b978-0-12-381517-0.00002-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The insulin secretory response to a meal results largely from glucose stimulation of the pancreatic islets and both direct and indirect (autonomic) glucose-dependent stimulation by incretin hormones released from the gastrointestinal tract. Two incretins, Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), have so far been identified. Localization of the cognate G protein-coupled receptors for GIP and GLP-1 revealed that they are present in numerous tissues in addition to the endocrine pancreas, including the gastrointestinal, cardiovascular, central nervous and autonomic nervous systems (ANSs), adipose tissue, and bone. At these sites, the incretin hormones exert a range of pleiotropic effects, many of which contribute to the integration of processes involved in the regulation of food intake, and nutrient and mineral processing and storage. From detailed studies at the cellular and molecular level, it is also evident that both incretin hormones act via multiple signal transduction pathways that regulate both acute and long-term cell function. Here, we provide an overview of current knowledge relating to the physiological roles of GIP and GLP-1, with specific emphasis on their modes of action on islet hormone secretion, β-cell proliferation and survival, central and autonomic neuronal function, gastrointestinal motility, and glucose and lipid metabolism. However, it is emphasized that despite intensive research on the various body systems, in many cases there is uncertainty as to the pathways by which the incretins mediate their pleiotropic effects and only a rudimentary understanding of the underlying cellular mechanisms involved, and these are challenges for the future.
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Affiliation(s)
- Christopher H S McIntosh
- Department of Cellular & Physiological Sciences and the Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
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Williams DL. Minireview: finding the sweet spot: peripheral versus central glucagon-like peptide 1 action in feeding and glucose homeostasis. Endocrinology 2009; 150:2997-3001. [PMID: 19389830 PMCID: PMC2703557 DOI: 10.1210/en.2009-0220] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Glucagon-like peptide 1 (GLP-1) is both a gut-derived hormone and a neurotransmitter synthesized in the brain. Early reports suggested that GLP-1 acts in the periphery to promote insulin secretion and affect glucose homeostasis, whereas central GLP-1 reduces food intake and body weight. However, current research indicates that in fact, GLP-1 in each location plays a role in these functions. This review summarizes the evidence for involvement of peripheral and brain GLP-1 in food intake regulation and glucose homeostasis and proposes a model for the coordinated actions of GLP-1 at multiple sites.
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Affiliation(s)
- Diana L Williams
- Department of Psychology, 1107 West Call Street, Florida State University, Tallahassee, Florida 32306-4301, USA.
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Direct control of peripheral lipid deposition by CNS GLP-1 receptor signaling is mediated by the sympathetic nervous system and blunted in diet-induced obesity. J Neurosci 2009; 29:5916-25. [PMID: 19420258 DOI: 10.1523/jneurosci.5977-08.2009] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We investigated a possible role of the central glucagon-like peptide (GLP-1) receptor system as an essential brain circuit regulating adiposity through effects on nutrient partitioning and lipid metabolism independent from feeding behavior. Both lean and diet-induced obesity mice were used for our experiments. GLP-1 (7-36) amide was infused in the brain for 2 or 7 d. The expression of key enzymes involved in lipid metabolism was measured by real-time PCR or Western blot. To test the hypothesis that the sympathetic nervous system may be responsible for informing adipocytes about changes in CNS GLP-1 tone, we have performed direct recording of sympathetic nerve activity combined with experiments in genetically manipulated mice lacking beta-adrenergic receptors. Intracerebroventricular infusion of GLP-1 in mice directly and potently decreases lipid storage in white adipose tissue. These effects are independent from nutrient intake. Such CNS control of adipocyte metabolism was found to depend partially on a functional sympathetic nervous system. Furthermore, the effects of CNS GLP-1 on adipocyte metabolism were blunted in diet-induced obese mice. The CNS GLP-1 system decreases fat storage via direct modulation of adipocyte metabolism. This CNS GLP-1 control of adipocyte lipid metabolism appears to be mediated at least in part by the sympathetic nervous system and is independent of parallel changes in food intake and body weight. Importantly, the CNS GLP-1 system loses the capacity to modulate adipocyte metabolism in obese states, suggesting an obesity-induced adipocyte resistance to CNS GLP-1.
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Girard J. The incretins: From the concept to their use in the treatment of type 2 diabetes. Part A: Incretins: Concept and physiological functions. DIABETES & METABOLISM 2008; 34:550-9. [DOI: 10.1016/j.diabet.2008.09.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2008] [Accepted: 09/01/2008] [Indexed: 12/25/2022]
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