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Hoornenborg C, van Dijk T, Bruggink J, van Beek A, van Dijk G. Acute sub-diaphragmatic anterior vagus nerve stimulation increases peripheral glucose uptake in anaesthetized rats. IBRO Neurosci Rep 2023; 15:50-56. [PMID: 37415729 PMCID: PMC10320406 DOI: 10.1016/j.ibneur.2023.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 06/15/2023] [Indexed: 07/08/2023] Open
Abstract
The sub-diaphragmatic vagus innervates various organs involved in the control of glucose homeostasis including the liver, pancreas and the intestines. In the current study, we investigated the effect of acute electrical stimulation of the anterior trunk of the sub-diaphragmatic vagus on glucose fluxes in anaesthetized adult male rats. After overnight fast, rats underwent either vagus nerve stimulation (VNS+, n = 11; rectangular pulses at 5 Hz, 1.5 mA, 1 msec pulse width) or sham stimulation (VNS-; n = 11) for 120 min under isoflurane anesthesia. Before stimulation, the rats received an i.v. bolus of 1 mL/kg of a sterilized aqueous solution containing 125 mg/mL of D-[6,6-2H2] glucose. Endogenous glucose production (EGP) and glucose clearance rate (GCR) were calculated by kinetic analysis from the wash-out of injected D-[6,6-2H2]glucose from the circulation. VNS+ resulted in lower glucose levels compared to the VNS- group (p < 0.05), with similar insulin levels. EGP was similar in both groups, but the GCR was higher in the VNS+ group compared to the VNS- group (p < 0.001). Circulating levels of the sympathetic transmitter norepinephrine were reduced by VNS+ relative to VNS- treatment (p < 0.01). It is concluded that acute anterior sub-diaphragmatic VNS causes stimulation of peripheral glucose uptake, while plasma insulin levels remained similar, and this is associated with lower activity of the sympathetic nervous system.
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Affiliation(s)
- C.W. Hoornenborg
- Groningen Institute for Evolutionary Life Sciences (GELIFES), Department of Behavioral Neuroscience, University of Groningen, Groningen, the Netherlands
- Department of Endocrinology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - T.H. van Dijk
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - J.E. Bruggink
- Groningen Institute for Evolutionary Life Sciences (GELIFES), Department of Behavioral Neuroscience, University of Groningen, Groningen, the Netherlands
| | - A.P. van Beek
- Department of Endocrinology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - G. van Dijk
- Groningen Institute for Evolutionary Life Sciences (GELIFES), Department of Behavioral Neuroscience, University of Groningen, Groningen, the Netherlands
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2
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Fernandois D, Vázquez MJ, Barroso A, Paredes AH, Tena-Sempere M, Cruz G. Multi-Organ Increase in Norepinephrine Levels after Central Leptin Administration and Diet-Induced Obesity. Int J Mol Sci 2023; 24:16909. [PMID: 38069231 PMCID: PMC10706686 DOI: 10.3390/ijms242316909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/17/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
Autonomic innervation is important to regulate homeostasis in every organ of the body. The sympathetic nervous system controls several organs associated with metabolism and reproduction, including adipose tissue, the liver, and the ovaries. The sympathetic nervous system is controlled within the central nervous system by neurons located in the hypothalamus, which in turn are regulated by hormones like leptin. Leptin action in the hypothalamus leads to increased sympathetic activity in the adipose tissue. In this short report, we propose that leptin action in the brain also controls the sympathetic innervation of other organs like the liver and the ovary. We performed two experiments: We performed an intracerebroventricular (ICV) injection of leptin and measured norepinephrine levels in several organs, and we used a validated model of overnutrition and obesity to evaluate whether an increase in leptin levels coexists with high levels of norepinephrine in the liver and ovaries. Norepinephrine was measured by ELISA in adipose tissue and by HPLC-EC in other tissues. Leptin was measured by ELISA. We found that the ICV injection of leptin increases norepinephrine levels in several organs, including the liver and ovaries. Also, we found that diet-induced obesity leads to an increase in leptin levels while inducing an increase in norepinephrine levels in the liver and ovaries. Finally, since hyperactivity of the sympathetic nervous system is observed both in non-alcoholic fatty liver disease and polycystic ovary syndrome, we think that an increase in norepinephrine levels induced by hyperleptinemia could be involved in the pathogenesis of both diseases.
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Affiliation(s)
- Daniela Fernandois
- Center for Neurobiochemical Studies in Endocrine Diseases, Laboratory of Neurobiochemistry, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago 7820436, Chile; (D.F.); (A.H.P.)
| | - María Jesús Vázquez
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, 14004 Cordoba, Spain; (M.J.V.); (A.B.); (M.T.-S.)
- Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, 28029 Madrid, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba, Hospital Universitario Reina Sofia, 14004 Cordoba, Spain
| | - Alexia Barroso
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, 14004 Cordoba, Spain; (M.J.V.); (A.B.); (M.T.-S.)
- Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, 28029 Madrid, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba, Hospital Universitario Reina Sofia, 14004 Cordoba, Spain
| | - Alfonso H. Paredes
- Center for Neurobiochemical Studies in Endocrine Diseases, Laboratory of Neurobiochemistry, Department of Biochemistry and Molecular Biology, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago 7820436, Chile; (D.F.); (A.H.P.)
| | - Manuel Tena-Sempere
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, 14004 Cordoba, Spain; (M.J.V.); (A.B.); (M.T.-S.)
- Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, 28029 Madrid, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba, Hospital Universitario Reina Sofia, 14004 Cordoba, Spain
| | - Gonzalo Cruz
- Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso 2360102, Chile
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Haspula D, Cui Z. Neurochemical Basis of Inter-Organ Crosstalk in Health and Obesity: Focus on the Hypothalamus and the Brainstem. Cells 2023; 12:1801. [PMID: 37443835 PMCID: PMC10341274 DOI: 10.3390/cells12131801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/23/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023] Open
Abstract
Precise neural regulation is required for maintenance of energy homeostasis. Essential to this are the hypothalamic and brainstem nuclei which are located adjacent and supra-adjacent to the circumventricular organs. They comprise multiple distinct neuronal populations which receive inputs not only from other brain regions, but also from circulating signals such as hormones, nutrients, metabolites and postprandial signals. Hence, they are ideally placed to exert a multi-tier control over metabolism. The neuronal sub-populations present in these key metabolically relevant nuclei regulate various facets of energy balance which includes appetite/satiety control, substrate utilization by peripheral organs and glucose homeostasis. In situations of heightened energy demand or excess, they maintain energy homeostasis by restoring the balance between energy intake and expenditure. While research on the metabolic role of the central nervous system has progressed rapidly, the neural circuitry and molecular mechanisms involved in regulating distinct metabolic functions have only gained traction in the last few decades. The focus of this review is to provide an updated summary of the mechanisms by which the various neuronal subpopulations, mainly located in the hypothalamus and the brainstem, regulate key metabolic functions.
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Affiliation(s)
- Dhanush Haspula
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Zhenzhong Cui
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA;
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Daniel JM, Lindsey SH, Mostany R, Schrader LA, Zsombok A. Cardiometabolic health, menopausal estrogen therapy and the brain: How effects of estrogens diverge in healthy and unhealthy preclinical models of aging. Front Neuroendocrinol 2023; 70:101068. [PMID: 37061205 PMCID: PMC10725785 DOI: 10.1016/j.yfrne.2023.101068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/23/2023] [Accepted: 04/10/2023] [Indexed: 04/17/2023]
Abstract
Research in preclinical models indicates that estrogens are neuroprotective and positively impact cognitive aging. However, clinical data are equivocal as to the benefits of menopausal estrogen therapy to the brain and cognition. Pre-existing cardiometabolic disease may modulate mechanisms by which estrogens act, potentially reducing or reversing protections they provide against cognitive decline. In the current review we propose mechanisms by which cardiometabolic disease may alter estrogen effects, including both alterations in actions directly on brain memory systems and actions on cardiometabolic systems, which in turn impact brain memory systems. Consideration of mechanisms by which estrogen administration can exert differential effects dependent upon health phenotype is consistent with the move towards precision or personalized medicine, which aims to determine which treatment interventions will work for which individuals. Understanding effects of estrogens in both healthy and unhealthy models of aging is critical to optimizing the translational link between preclinical and clinical research.
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Affiliation(s)
- Jill M Daniel
- Department of Psychology and Brain Institute, Tulane University, New Orleans, LA, United States.
| | - Sarah H Lindsey
- Department of Pharmacology and Brain Institute, Tulane University, New Orleans, LA, United States
| | - Ricardo Mostany
- Department of Pharmacology and Brain Institute, Tulane University, New Orleans, LA, United States
| | - Laura A Schrader
- Department of Cell & Molecular Biology and Brain Institute, Tulane University, New Orleans, LA, United States
| | - Andrea Zsombok
- Department of Physiology and Brain Institute, Tulane University, New Orleans, LA, United States
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5
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Tanimizu N, Ichinohe N, Mitaka T. β-adrenergic receptor agonist promotes ductular expansion during 3,5-diethoxycarbonyl-1,4-dihydrocollidine-induced chronic liver injury. Sci Rep 2023; 13:7084. [PMID: 37127664 PMCID: PMC10151327 DOI: 10.1038/s41598-023-33882-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 04/20/2023] [Indexed: 05/03/2023] Open
Abstract
Intrahepatic nerves are involved in the regulation of metabolic reactions and hepatocyte-based regeneration after surgical resection, although their contribution to chronic liver injury remains unknown. Given that intrahepatic nerves are abundant in the periportal tissue, they may be correlated also with cholangiocyte-based regeneration. Here we demonstrate that isoproterenol (ISO), a β-adrenergic receptor agonist, promoted ductular expansion induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) in vivo. Immunofluorescence analysis shows that nerve fibers positive for tyrosine hydroxylase form synaptophysin-positive nerve endings on epithelial cell adhesion molecule-positive (EpCAM+) cholangiocytes as well as on Thy1+ periportal mesenchymal cells (PMCs) that surround bile ducts, suggesting that the intrahepatic biliary tissue are targeted by sympathetic nerves. In vitro analyses indicate that ISO directly increases cAMP levels in cholangiocytes and PMCs. Mechanistically, ISO expands the lumen of cholangiocyte organoids, resulting in promotion of cholangiocyte proliferation, whereas it increases expression of fibroblast growth factor 7, a growth factor for cholangiocytes, in PMCs. Taken together, the results indicate that intrahepatic sympathetic nerves regulate remodeling of bile ducts during DDC-injury by the activation of β-adrenergic receptors on cholangiocytes and PMCs.
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Affiliation(s)
- Naoki Tanimizu
- Department of Tissue Development and Regeneration, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, S-1, W-17, Chuo-ku, Sapporo, 060-8556, Japan.
- Division of Regenerative Medicine, Center for Stem Cell Biology and Regenerative Medicine, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-0071, Japan.
| | - Norihisa Ichinohe
- Department of Tissue Development and Regeneration, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, S-1, W-17, Chuo-ku, Sapporo, 060-8556, Japan
| | - Toshihiro Mitaka
- Department of Tissue Development and Regeneration, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, S-1, W-17, Chuo-ku, Sapporo, 060-8556, Japan
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Wang Y, An Z, Lin D, Jin W. Targeting cancer cachexia: Molecular mechanisms and clinical study. MedComm (Beijing) 2022; 3:e164. [PMID: 36105371 PMCID: PMC9464063 DOI: 10.1002/mco2.164] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/01/2022] [Accepted: 07/07/2022] [Indexed: 11/12/2022] Open
Abstract
Cancer cachexia is a complex systemic catabolism syndrome characterized by muscle wasting. It affects multiple distant organs and their crosstalk with cancer constitute cancer cachexia environment. During the occurrence and progression of cancer cachexia, interactions of aberrant organs with cancer cells or other organs in a cancer cachexia environment initiate a cascade of stress reactions and destroy multiple organs including the liver, heart, pancreas, intestine, brain, bone, and spleen in metabolism, neural, and immune homeostasis. The role of involved organs turned from inhibiting tumor growth into promoting cancer cachexia in cancer progression. In this review, we depicted the complicated relationship of cancer cachexia with the metabolism, neural, and immune homeostasis imbalance in multiple organs in a cancer cachexia environment and summarized the treatment progress in recent years. And we discussed the molecular mechanism and clinical study of cancer cachexia from the perspective of multiple organs metabolic, neurological, and immunological abnormalities. Updated understanding of cancer cachexia might facilitate the exploration of biomarkers and novel therapeutic targets of cancer cachexia.
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Affiliation(s)
- Yong‐Fei Wang
- The First Clinical Medical College of Lanzhou University Lanzhou China
- Institute of Cancer Neuroscience Medical Frontier Innovation Research Center The First Hospital of Lanzhou University Lanzhou China
| | - Zi‐Yi An
- The First Clinical Medical College of Lanzhou University Lanzhou China
- Institute of Cancer Neuroscience Medical Frontier Innovation Research Center The First Hospital of Lanzhou University Lanzhou China
| | - Dong‐Hai Lin
- Key Laboratory for Chemical Biology of Fujian Province MOE Key Laboratory of Spectrochemical Analysis and Instrumentation College of Chemistry and Chemical Engineering Xiamen University Xiamen China
| | - Wei‐Lin Jin
- The First Clinical Medical College of Lanzhou University Lanzhou China
- Institute of Cancer Neuroscience Medical Frontier Innovation Research Center The First Hospital of Lanzhou University Lanzhou China
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7
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Martinez-Sanchez N, Sweeney O, Sidarta-Oliveira D, Caron A, Stanley SA, Domingos AI. The sympathetic nervous system in the 21st century: Neuroimmune interactions in metabolic homeostasis and obesity. Neuron 2022; 110:3597-3626. [PMID: 36327900 PMCID: PMC9986959 DOI: 10.1016/j.neuron.2022.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 08/23/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022]
Abstract
The sympathetic nervous system maintains metabolic homeostasis by orchestrating the activity of organs such as the pancreas, liver, and white and brown adipose tissues. From the first renderings by Thomas Willis to contemporary techniques for visualization, tracing, and functional probing of axonal arborizations within organs, our understanding of the sympathetic nervous system has started to grow beyond classical models. In the present review, we outline the evolution of these findings and provide updated neuroanatomical maps of sympathetic innervation. We offer an autonomic framework for the neuroendocrine loop of leptin action, and we discuss the role of immune cells in regulating sympathetic terminals and metabolism. We highlight potential anti-obesity therapeutic approaches that emerge from the modern appreciation of SNS as a neural network vis a vis the historical fear of sympathomimetic pharmacology, while shifting focus from post- to pre-synaptic targeting. Finally, we critically appraise the field and where it needs to go.
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Affiliation(s)
| | - Owen Sweeney
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Davi Sidarta-Oliveira
- Physician-Scientist Graduate Program, Obesity and Comorbidities Research Center, School of Medical Sciences, University of Campinas, Campinas, Brazil
| | - Alexandre Caron
- Faculty of Pharmacy, Université Laval, Québec City, QC G1V 0A6, Canada
| | - Sarah A Stanley
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ana I Domingos
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK.
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8
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Silva A, Caron A. Pathophysiological Mechanisms That Alter the Autonomic Brain-Liver Communication in Metabolic Diseases. Endocrinology 2021; 162:bqab164. [PMID: 34388249 PMCID: PMC8455344 DOI: 10.1210/endocr/bqab164] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Indexed: 11/19/2022]
Abstract
The brain influences liver metabolism through many neuroendocrine and autonomic mechanisms that have evolved to protect the organism against starvation and hypoglycemia. Unfortunately, this effective way of preventing death has become dysregulated in modern obesogenic environments, although the pathophysiological mechanisms behind metabolic dyshomeostasis are still unclear. In this Mini-Review, we provide our thoughts regarding obesity and type 2 diabetes as diseases of the autonomic nervous system. We discuss the pathophysiological mechanisms that alter the autonomic brain-liver communication in these diseases, and how they could represent important targets to prevent or treat metabolic dysfunctions. We discuss how sympathetic hyperactivity to the liver may represent an early event in the progression of metabolic diseases and could progressively lead to hepatic neuropathy. We hope that this discussion will inspire and help to frame a model based on better understanding of the chronology of autonomic dysfunctions in the liver, enabling the application of the right strategy at the right time.
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Affiliation(s)
- Anisia Silva
- Faculty of Pharmacy, Université Laval, Québec City, QC G1V 0A6, Canada
- Quebec Heart and Lung Institute, Québec City, QC G1V 4G5, Canada
| | - Alexandre Caron
- Faculty of Pharmacy, Université Laval, Québec City, QC G1V 0A6, Canada
- Quebec Heart and Lung Institute, Québec City, QC G1V 4G5, Canada
- Montreal Diabetes Research Center, Montreal, QC H2X 0A9, Canada
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9
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Komori K, Usui M, Hatano K, Hori Y, Hirono K, Zhu D, Tokito F, Nishikawa M, Sakai Y, Kimura H. In vitro enzymatic electrochemical monitoring of glucose metabolism and production in rat primary hepatocytes on highly O 2 permeable plates. Bioelectrochemistry 2021; 143:107972. [PMID: 34666223 DOI: 10.1016/j.bioelechem.2021.107972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 12/12/2022]
Abstract
In situ continuous glucose monitoring under physiological culture conditions is imperative in understanding the dynamics of cell and tissue behaviors and their physiological responses since glucose plays an important role in principal source of biological energy. We therefore examined physiologically relevant dynamic changes in glucose levels based on glucose metabolism and production during aerobic culture (10% O2) of rat primary hepatocytes stimulated with insulin or glucagon on a highly O2 permeable plate, which can maintain the oxygen concentration close to the periportal zone of the liver. As glucose monitoring devices, we used oxygen-independent glucose dehydrogenase-modified single-walled carbon nanotube electrodes placed close to the surface of the hepatocytes. The current response of glucose oxidation slightly decreased after the addition of insulin in the presence of glucose due to the acceleration of glucose uptake by the hepatocytes, whereas that significantly increased after the addition of glucagon and fructose even in the absence of glucose due to the conversion of fructose to glucose based on gluconeogenesis. These phenomena might be consistent relatively with the physiological behaviors of hepatocytes in the periportal region. The present monitoring system would be useful for the studies of glucose homeostasis and diabetes in vitro.
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Affiliation(s)
- Kikuo Komori
- Department of Biotechnology and Chemistry, Kindai University, Takaya-Umenobe, Higashi-Hiroshima 739-2116, Japan; Department of Chemical System Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Masataka Usui
- Department of Chemical System Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kohei Hatano
- Department of Chemical System Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yuma Hori
- Department of Biotechnology and Chemistry, Kindai University, Takaya-Umenobe, Higashi-Hiroshima 739-2116, Japan
| | - Keita Hirono
- Department of Chemical System Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Dongchen Zhu
- Department of Chemical System Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Fumiya Tokito
- Department of Chemical System Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Masaki Nishikawa
- Department of Chemical System Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yasuyuki Sakai
- Department of Chemical System Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Hiroshi Kimura
- Department of Mechanical Engineering, Tokai University, Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
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Xiu AY, Ding Q, Li Z, Zhang CQ. Doxazosin Attenuates Liver Fibrosis by Inhibiting Autophagy in Hepatic Stellate Cells via Activation of the PI3K/Akt/mTOR Signaling Pathway. DRUG DESIGN DEVELOPMENT AND THERAPY 2021; 15:3643-3659. [PMID: 34456560 PMCID: PMC8387324 DOI: 10.2147/dddt.s317701] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/03/2021] [Indexed: 12/12/2022]
Abstract
Purpose To investigate the effect of doxazosin on autophagy and the activation of hepatic stellate cells (HSCs) in vivo and in vitro and determine the underlying mechanism. Methods In vivo, a mouse liver fibrosis model was induced by the intraperitoneal injection of carbon tetrachloride (CCl4). Doxazosin was administered at doses of 2.5, 5 and 10 mg/(kg*day) by gavage. After 20 weeks, blood and liver tissues were collected for serological and histological analysis, respectively. Blood analysis, hematoxylin and eosin (HE) staining, Masson’s trichrome staining, immunohistochemistry and immunofluorescence staining were used to measure the extent of liver fibrosis in model and control mice. In vitro, the human HSC cell line LX-2 was cultured and treated with different doses of doxazosin for the indicated times. The effects of doxazosin on LX-2 cell proliferation and migration were examined by Cell Counting Kit-8 (CCK-8) and Transwell assays, respectively. The number of autophagosomes in LX-2 cells was observed by transmission electron microscopy (TEM). Infection with green fluorescent protein (GFP)-LC3B adenovirus, GFP-red fluorescent protein (RFP)-LC3B adenovirus and mCherry-EGFP-LC3 adeno-associated virus was performed to examine changes in autophagic flux in vitro and in vivo. Cell apoptosis was measured by flow cytometry in vitro and by TUNEL assays both in vitro and in vivo. Immunoblotting was performed to evaluate the expression levels of proteins related to fibrosis, autophagy, apoptosis, and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR). Results Doxazosin inhibited HSC proliferation and migration. HSC activation was attenuated by doxazosin in a concentration-dependent manner in vivo and in vitro. Doxazosin also blocked autophagic flux and induced apoptosis in HSCs. In addition, the PI3K/Akt/mTOR pathway was activated by doxazosin and regulated fibrosis, autophagy and apoptosis in HSCs. Conclusion The study confirmed that doxazosin could inhibit autophagy by activating the PI3K/Akt/mTOR signaling pathway and attenuate liver fibrosis.
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Affiliation(s)
- Ai-Yuan Xiu
- Department of Gastroenterology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, People's Republic of China
| | - Qian Ding
- Department of Gastroenterology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, People's Republic of China
| | - Zhen Li
- Department of Gastroenterology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, People's Republic of China
| | - Chun-Qing Zhang
- Department of Gastroenterology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, People's Republic of China.,Department of Gastroenterology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, People's Republic of China
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11
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Colonna CH, Henriquez AR, House JS, Motsinger-Reif AA, Alewel DI, Fisher A, Ren H, Snow SJ, Schladweiler MC, Miller DB, Miller CN, Kodavanti PRS, Kodavanti UP. The Role of Hepatic Vagal Tone in Ozone-Induced Metabolic Dysfunction in the Liver. Toxicol Sci 2021; 181:229-245. [PMID: 33662111 DOI: 10.1093/toxsci/kfab025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Air pollution has been associated with metabolic diseases and hepatic steatosis-like changes. We have shown that ozone alters liver gene expression for metabolic processes through neuroendocrine activation. This study aimed to further characterize ozone-induced changes and to determine the impact of hepatic vagotomy (HV) which reduces parasympathetic influence. Twelve-week-old male Wistar-Kyoto rats underwent HV or sham surgery 5-6 days before air or ozone exposure (0 or 1 ppm; 4 h/day for 1 or 2 days). Ozone-induced lung injury, hyperglycemia, glucose intolerance, and increases in circulating cholesterol, triglycerides, and leptin were similar in rats with HV and sham surgery. However, decreases in circulating insulin and increased HDL and LDL were observed only in ozone-exposed HV rats. Ozone exposure resulted in changed liver gene expression in both sham and HV rats (sham > HV), however, HV did not change expression in air-exposed rats. Upstream target analysis revealed that ozone-induced transcriptomic changes were similar to responses induced by glucocorticoid-mediated processes in both sham and HV rats. The directionality of ozone-induced changes reflecting cellular response to stress, metabolic pathways, and immune surveillance was similar in sham and HV rats. However, pathways regulating cell-cycle, regeneration, proliferation, cell growth, and survival were enriched by ozone in a directionally opposing manner between sham and HV rats. In conclusion, parasympathetic innervation modulated ozone-induced liver transcriptional responses for cell growth and regeneration without affecting stress-mediated metabolic changes. Thus, impaired neuroendocrine axes and parasympathetic innervation could collectively contribute to adverse effects of air pollutants on the liver.
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Affiliation(s)
- Catherine H Colonna
- Oak Ridge Institute for Science and Education Research Participation Program, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711
| | - Andres R Henriquez
- Oak Ridge Institute for Science and Education Research Participation Program, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711
| | - John S House
- Division of Intramural Research, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Alison A Motsinger-Reif
- Division of Intramural Research, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Devin I Alewel
- Oak Ridge Institute for Science and Education Research Participation Program, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711
| | - Anna Fisher
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Hongzu Ren
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Samantha J Snow
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Mette C Schladweiler
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Desinia B Miller
- Curriculum in Toxicology and Environmental Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Colette N Miller
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Prasada Rao S Kodavanti
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Urmila P Kodavanti
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
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12
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Torres H, Huesing C, Burk DH, Molinas AJR, Neuhuber WL, Berthoud HR, Münzberg H, Derbenev AV, Zsombok A. Sympathetic innervation of the mouse kidney and liver arising from prevertebral ganglia. Am J Physiol Regul Integr Comp Physiol 2021; 321:R328-R337. [PMID: 34231420 DOI: 10.1152/ajpregu.00079.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The sympathetic nervous system (SNS) plays a crucial role in the regulation of renal and hepatic functions. Although sympathetic nerves to the kidney and liver have been identified in many species, specific details are lacking in the mouse. In the absence of detailed information of sympathetic prevertebral innervation of specific organs, selective manipulation of a specific function will remain challenging. Despite providing major postganglionic inputs to abdominal organs, limited data are available about the mouse celiac-superior mesenteric complex. We used tyrosine hydroxylase (TH) and dopamine β-hydroxylase (DbH) reporter mice to visualize abdominal prevertebral ganglia. We found that both the TH and DbH reporter mice are useful models for identification of ganglia and nerve bundles. We further tested if the celiac-superior mesenteric complex provides differential inputs to the mouse kidney and liver. The retrograde viral tracer, pseudorabies virus (PRV)-152 was injected into the cortex of the left kidney or the main lobe of the liver to identify kidney-projecting and liver-projecting neurons in the celiac-superior mesenteric complex. iDISCO immunostaining and tissue clearing were used to visualize unprecedented anatomical detail of kidney-related and liver-related postganglionic neurons in the celiac-superior mesenteric complex and aorticorenal and suprarenal ganglia compared with TH-positive neurons. Kidney-projecting neurons were restricted to the suprarenal and aorticorenal ganglia, whereas only sparse labeling was observed in the celiac-superior mesenteric complex. In contrast, liver-projecting postganglionic neurons were observed in the celiac-superior mesenteric complex and aorticorenal and suprarenal ganglia, suggesting spatial separation between the sympathetic innervation of the mouse kidney and liver.
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Affiliation(s)
- Hayden Torres
- Neurobiology of Nutrition and Metabolism Department, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
| | - Clara Huesing
- Neurobiology of Nutrition and Metabolism Department, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
| | - David H Burk
- Neurobiology of Nutrition and Metabolism Department, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
| | - Adrien J R Molinas
- Department of Physiology, School of Medicine, Tulane University, New Orleans, Louisiana
| | | | - Hans-Rudolf Berthoud
- Neurobiology of Nutrition and Metabolism Department, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
| | - Heike Münzberg
- Neurobiology of Nutrition and Metabolism Department, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
| | - Andrei V Derbenev
- Department of Physiology, School of Medicine, Tulane University, New Orleans, Louisiana.,Brain Institute, Tulane University, New Orleans, Louisiana
| | - Andrea Zsombok
- Department of Physiology, School of Medicine, Tulane University, New Orleans, Louisiana.,Brain Institute, Tulane University, New Orleans, Louisiana
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13
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Ashraf S, Ashraf N, Yilmaz G, Harmancey R. Crosstalk between beta-adrenergic and insulin signaling mediates mechanistic target of rapamycin hyperactivation in liver of high-fat diet-fed male mice. Physiol Rep 2021; 9:e14958. [PMID: 34231324 PMCID: PMC8261682 DOI: 10.14814/phy2.14958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/17/2021] [Accepted: 06/17/2021] [Indexed: 11/24/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. While increased nutrient intake and sympathetic activity have been associated with the disease, the pathogenesis of NAFLD remains incompletely understood. We investigated the impact of the interaction of high dietary fat and sugar intake with increased beta-adrenergic receptor (β-AR) signaling on the activity of nutrient-sensing pathways and fuel storage in the liver. C57BL/6J mice were fed a standard rodent diet (STD), a high-fat diet (HFD), a high-fat/high-sugar Western diet (WD), a high-sugar diet with mixed carbohydrates (HCD), or a high-sucrose diet (HSD). After 6 week on diets, mice were treated with isoproterenol (ISO) and the activity of liver mTOR complex 1 (mTORC1)-related signaling analyzed by immunoblotting and correlated with tissue triglyceride and glycogen contents. ISO-stimulated AKT- and ERK-mediated activation of mTORC1 in STD-fed mice. Consumption of all four high-calorie diets exacerbated downstream activation of ribosomal protein S6 kinase beta-1 (S6K1) in response to ISO. S6K1 activity was greater with the fat-enriched HFD and WD and correlated with the presence of metabolic syndrome and a stronger activation of AKT and ERK1/2 pathways. Fat-enriched diets also increased triglyceride accumulation and inhibited glycogen mobilization under β-AR stimulation. In conclusion, crosstalk between β-AR and insulin signaling may contribute to HFD-induced hepatic steatosis through ERK1/2- and AKT-mediated hyperactivation of the mTORC1/S6K1 axis. The findings provide further rationale for the development of therapies aimed at targeting augmented β-AR signaling in the pathogenesis of NAFLD.
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Affiliation(s)
- Sadia Ashraf
- Department of Physiology and BiophysicsUniversity of Mississippi Medical CenterJacksonMSUSA
- Mississippi Center for Obesity ResearchUniversity of Mississippi Medical CenterJacksonMSUSA
| | | | - Gizem Yilmaz
- Department of Physiology and BiophysicsUniversity of Mississippi Medical CenterJacksonMSUSA
- Mississippi Center for Obesity ResearchUniversity of Mississippi Medical CenterJacksonMSUSA
| | - Romain Harmancey
- Department of Physiology and BiophysicsUniversity of Mississippi Medical CenterJacksonMSUSA
- Mississippi Center for Obesity ResearchUniversity of Mississippi Medical CenterJacksonMSUSA
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14
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Kraft G, Scott M, Allen E, Edgerton DS, Farmer B, Azamian BR, Cherrington AD. Safety of surgical denervation of the common hepatic artery in insulin-resistant dogs. Physiol Rep 2021; 9:e14805. [PMID: 33769710 PMCID: PMC7995543 DOI: 10.14814/phy2.14805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 12/17/2022] Open
Abstract
The objective of this study was to assess the safety of surgical common hepatic artery denervation (CHADN). This procedure has previously been shown to improve glucose tolerance in dogs fed a high-fat high-fructose (HFHF) diet. We assessed the hypoglycemic response of dogs by infusing insulin at a constant rate (1.5 mU/kg/min) for 3 h and monitoring glucose and the counterregulatory hormones (glucagon, catecholamine, and cortisol). After an initial hypoglycemic study, the dogs were randomly assigned to a SHAM surgery (n = 4) or hepatic sympathetic denervation (CHADN, n = 5) and three follow-up studies were performed every month up to 3 months after the surgery. The level of norepinephrine (NE) in the liver and the pancreas was significantly reduced in the CHADN dogs, showing a decrease in sympathetic tone to the splanchnic organs. There was no evidence of any defect of the response to hypoglycemia after the CHADN surgery. Indeed, the extent of hypoglycemia was similar in the SHAM and CHADN groups (~45 mg/dl) for the same amount of circulating insulin (~50 µU/ml) regardless of time or surgery. Moreover the responses of the counterregulatory hormones were similar in extent and pattern during the 3 h of hypoglycemic challenge. Circulating lactate, glycerol, free fatty acids, and beta-hydroxybutyrate were also unaffected by CHADN during fasting conditions or during the hypoglycemia. There were no other notable surgery-induced changes over time in nutrients, minerals, and hormones clinically measured in the dogs nor in the blood pressure and heart rate of the animals. The data suggest that the ablation of the sympathetic nerve connected to the splanchnic bed is not required for a normal counterregulatory response to insulin-induced hypoglycemia and that CHADN could be a safe new therapeutic intervention to improve glycemic control in individuals with metabolic syndrome or type 2 diabetes.
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Affiliation(s)
- Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Melanie Scott
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Eric Allen
- Hormone Assay and Analytical Services Core, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA.,Hormone Assay and Analytical Services Core, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | | | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
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15
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Kalsbeek A, Buijs RM. Organization of the neuroendocrine and autonomic hypothalamic paraventricular nucleus. HANDBOOK OF CLINICAL NEUROLOGY 2021; 180:45-63. [PMID: 34225948 DOI: 10.1016/b978-0-12-820107-7.00004-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A major function of the nervous system is to maintain a relatively constant internal environment. The distinction between our external environment (i.e., the environment that we live in and that is subject to major changes, such as temperature, humidity, and food availability) and our internal environment (i.e., the environment formed by the fluids surrounding our bodily tissues and that has a very stable composition) was pointed out in 1878 by Claude Bernard (1814-1878). Later on, it was indicated by Walter Cannon (1871-1945) that the internal environment is not really constant, but rather shows limited variability. Cannon named the mechanism maintaining this limited variability homeostasis. Claude Bernard envisioned that, for optimal health, all physiologic processes in the body needed to maintain homeostasis and should be in perfect harmony with each other. This is illustrated by the fact that, for instance, during the sleep-wake cycle important elements of our physiology such as body temperature, circulating glucose, and cortisol levels show important variations but are in perfect synchrony with each other. These variations are driven by the biologic clock in interaction with hypothalamic target areas, among which is the paraventricular nucleus of the hypothalamus (PVN), a core brain structure that controls the neuroendocrine and autonomic nervous systems and thus is key for integrating central and peripheral information and implementing homeostasis. This chapter focuses on the anatomic connections between the biologic clock and the PVN to modulate homeostasis according to the daily sleep-wake rhythm. Experimental studies have revealed a highly specialized organization of the connections between the clock neurons and neuroendocrine system as well as preautonomic neurons in the PVN. These complex connections ensure a logical coordination between behavioral, endocrine, and metabolic functions that helps the organism maintain homeostasis throughout the day.
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Affiliation(s)
- Andries Kalsbeek
- Department of Endocrinology and Metabolism, Amsterdam University Medical Centers (Amsterdam UMC), University of Amsterdam, Amsterdam, The Netherlands; Department of Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands.
| | - Ruud M Buijs
- Hypothalamic Integration Mechanisms Laboratory, Department of Cellular Biology and Physiology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
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16
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Optogenetic stimulation of the liver-projecting melanocortinergic pathway promotes hepatic glucose production. Nat Commun 2020; 11:6295. [PMID: 33293550 PMCID: PMC7722761 DOI: 10.1038/s41467-020-20160-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 11/18/2020] [Indexed: 12/18/2022] Open
Abstract
The central melanocortin system plays a fundamental role in the control of feeding and body weight. Proopiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus (ARC) also regulate overall glucose homeostasis via insulin-dependent and -independent pathways. Here, we report that a subset of ARC POMC neurons innervate the liver via preganglionic parasympathetic acetylcholine (ACh) neurons in the dorsal motor nucleus of the vagus (DMV). Optogenetic stimulation of this liver-projecting melanocortinergic pathway elevates blood glucose levels that is associated with increased expression of hepatic gluconeogenic enzymes in female and male mice. Pharmacological blockade and knockdown of the melanocortin-4 receptor gene in the DMV abolish this stimulation-induced effect. Activation of melanocortin-4 receptors inhibits DMV cholinergic neurons and optogenetic inhibition of liver-projecting parasympathetic cholinergic fibers increases blood glucose levels. This elevated blood glucose is not due to altered pancreatic hormone release. Interestingly, insulin-induced hypoglycemia increases ARC POMC neuron activity. Hence, this liver-projecting melanocortinergic circuit that we identified may play a critical role in the counterregulatory response to hypoglycemia. Hypothalamic melanocortin neurons regulate systemic glucose homeostasis through incompletely understood pathways. Here, the authors show that a subset of pro-opiomelanocortin neurons innervate the liver via preganglionic parasympathetic cholinergic neurons in the dorsal motor nucleus of the vagus and that stimulation of this pathway elevates blood glucose levels
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17
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Abstract
Metabolic control systems coordinate myriad processes across the cellular, tissue and organismal levels to optimize the allocation of limited supplies across multiple, often competing, metabolic demands. As such, the regulation of metabolism can be analysed from the perspective of the economic theory of supply and demand. Here, we discuss how such analyses can provide new insights into the logic of metabolic control. In particular, we suggest that, in addition to being subject to well-appreciated homeostatic control, metabolism is subject to supply-driven and demand-driven controls, each operated by a dedicated set of signals throughout various physiological states, including inflammation. Furthermore, we argue that systemic homeostasis is a derived feature that evolved from the control systems that monitor metabolic supply and demand.
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Affiliation(s)
- Jessica Ye
- Howard Hughes Medical Institute and Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Ruslan Medzhitov
- Howard Hughes Medical Institute and Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA.
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18
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Chen W, Liu H, Guan H, Xue N, Wang L. Cannabinoid CB 1 receptor inverse agonist MJ08 stimulates glucose production via hepatic sympathetic innervation in rats. Eur J Pharmacol 2017; 814:232-239. [PMID: 28844874 DOI: 10.1016/j.ejphar.2017.08.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 08/23/2017] [Accepted: 08/23/2017] [Indexed: 02/01/2023]
Abstract
As a key insulin target tissue for maintaining systemic glucose homeostasis, the liver plays important roles in improving obesity-associated insulin intolerance via selective cannabinoid CB1 receptor antagonism/inverse agonism. However, it is unclear whether this receptor inverse agonism affects hepatic glucose metabolism. MJ08 is a novel cannabinoid CB1 receptor antagonist/inverse agonist that has superior inverse agonism over the well-known antagonist/inverse agonist, SR141716 (rimonabant). MJ08 remarkably elevates fasting blood glucose independent of inhibition of insulin release in mice. In the current study, MJ08 was used to investigate the mechanism by which liver cannabinoid CB1 receptor inverse activation regulates hepatic glucose metabolism. MJ08 stimulated hepatic glucose production (HGP) in a dose-dependent manner and promoted gluconeogenic gene expression in perfused rat liver. SR141716 exhibited similar but weaker effects. The cannabinoid CB1 receptor agonist (WIN 55,212-2), Gs protein-cyclic AMP (cAMP)-dependent pathway inhibitors (NF449 and H89), β-adrenoceptor antagonist (propranolol), and peripheral sympathetic inhibitor (reserpine) could antagonize MJ08-induced HGP. Furthermore, MJ08 and SR141716 induced monoamine neurotransmitter (noradrenaline) release and increased cAMP content significantly in perfused liver, although only a slight increase was observed in primary cultured hepatocytes. These results indicate that local liver cannabinoid CB1 receptor inverse agonism via hepatic sympathetic innervation is responsible for the HGP induced by MJ08. Thus, high inverse agonistic activity could increase fasting blood glucose levels and should be avoided in the development of peripheral cannabinoid CB1 receptor-targeted weight-loss drugs.
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Affiliation(s)
- Wei Chen
- Beijing Institute of Pharmacology and Toxicology, Beijing 100850, PR China; State Key Laboratory of Toxicology and Medical Countermeasures, Beijing 100850, China
| | - Hongying Liu
- Beijing Institute of Pharmacology and Toxicology, Beijing 100850, PR China
| | - Hua Guan
- Beijing Institute of Pharmacology and Toxicology, Beijing 100850, PR China
| | - Nina Xue
- Beijing Institute of Pharmacology and Toxicology, Beijing 100850, PR China; State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Lili Wang
- Beijing Institute of Pharmacology and Toxicology, Beijing 100850, PR China; State Key Laboratory of Toxicology and Medical Countermeasures, Beijing 100850, China.
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19
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Huang JC, Chen CF, Chang CC, Chen SC, Hsieh MC, Hsieh YP, Chen HC. Effects of stroke on changes in heart rate variability during hemodialysis. BMC Nephrol 2017; 18:90. [PMID: 28302058 PMCID: PMC5353962 DOI: 10.1186/s12882-017-0502-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 03/07/2017] [Indexed: 12/03/2022] Open
Abstract
Background Stroke and low heart rate variability (HRV) are both associated with an unfavorable prognosis in hemodialysis patients. The relationship between stroke and changes in HRV during hemodialysis remains unclear. Methods This study measured differences between predialysis and postdialysis HRV (△HRV) in 182 maintenance hemodialysis patients, including 30 patients with stroke, to assess changes in HRV during hemodialysis, and also to compare results to 114 healthy controls. Results All predialysis HRV measurements had no differences between stroke patients and those without stroke, but were lower than healthy controls. Postdialysis very low frequency (VLF) (P < 0.001), low frequency (LF) (P = 0.001), total power (TP) (P < 0.001) and the LF/high frequency (HF) ratio (P < 0.001) increased significantly relative to predialysis values in patients without stroke, whereas postdialysis HRV did not increase in stroke patients. After multivariate adjustment, dialysis vintage was negatively associated with △VLF (β = -0.698, P = 0.046), △LF (β = -0.931, P = 0.009), and △TP (β = -0.887, P = 0.012) in patients without stroke. Serum intact parathyroid hormone (β = -0.707, P = 0.019) was negatively associated with △LF. Total cholesterol (β = -0.008, P = 0.001) and high sensitivity C-reactive protein (β = -0.474, P = 0.012) were inversely correlated with the △LF/HF ratio in patients without stroke. Conclusion HRV in hemodialysis patients is lower than in the general population. Increase in △HRV was observed in hemodialysis patients without stroke but not in stroke patients. This result suggests suppressed autonomic nervous reactions against volume unloading during hemodialysis, which might contribute to unfavorable outcomes in hemodialysis patients but even more so in those with prior stroke. Nephrologists should notice the importance of △HRV especially in high-risk patients.
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Affiliation(s)
- Jiun-Chi Huang
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Division of Nephrology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Internal Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chien-Fu Chen
- Division of Neurology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chia-Chu Chang
- Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, 135 Nanxiao Street, Changhua City, 500, Taiwan.,School of Medicine, Chung Shan Medical University, Taichung, Taiwan.,Program for Aging, China Medical University, Taichung, Taiwan
| | - Szu-Chia Chen
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Division of Nephrology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Internal Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Ming-Chia Hsieh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan.,Graduate Institute of Integrated Medicine, China Medical University, Taichung, Taiwan
| | - Yao-Peng Hsieh
- Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. .,Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, 135 Nanxiao Street, Changhua City, 500, Taiwan. .,School of Medicine, Chung Shan Medical University, Taichung, Taiwan.
| | - Hung-Chun Chen
- Division of Nephrology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Faculty of Renal Care, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
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20
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The stellate cell system (vitamin A-storing cell system). Anat Sci Int 2017; 92:387-455. [PMID: 28299597 DOI: 10.1007/s12565-017-0395-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 02/15/2017] [Indexed: 01/18/2023]
Abstract
Past, present, and future research into hepatic stellate cells (HSCs, also called vitamin A-storing cells, lipocytes, interstitial cells, fat-storing cells, or Ito cells) are summarized and discussed in this review. Kupffer discovered black-stained cells in the liver using the gold chloride method and named them stellate cells (Sternzellen in German) in 1876. Wake rediscovered the cells in 1971 using the same gold chloride method and various modern histological techniques including electron microscopy. Between their discovery and rediscovery, HSCs disappeared from the research history. Their identification, the establishment of cell isolation and culture methods, and the development of cellular and molecular biological techniques promoted HSC research after their rediscovery. In mammals, HSCs exist in the space between liver parenchymal cells (PCs) or hepatocytes and liver sinusoidal endothelial cells (LSECs) of the hepatic lobule, and store 50-80% of all vitamin A in the body as retinyl ester in lipid droplets in the cytoplasm. SCs also exist in extrahepatic organs such as pancreas, lung, and kidney. Hepatic (HSCs) and extrahepatic stellate cells (EHSCs) form the stellate cell (SC) system or SC family; the main storage site of vitamin A in the body is HSCs in the liver. In pathological conditions such as liver fibrosis, HSCs lose vitamin A, and synthesize a large amount of extracellular matrix (ECM) components including collagen, proteoglycan, glycosaminoglycan, and adhesive glycoproteins. The morphology of these cells also changes from the star-shaped HSCs to that of fibroblasts or myofibroblasts.
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21
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Bruce KD, Zsombok A, Eckel RH. Lipid Processing in the Brain: A Key Regulator of Systemic Metabolism. Front Endocrinol (Lausanne) 2017; 8:60. [PMID: 28421037 PMCID: PMC5378716 DOI: 10.3389/fendo.2017.00060] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/17/2017] [Indexed: 12/25/2022] Open
Abstract
Metabolic disorders, particularly aberrations in lipid homeostasis, such as obesity, type 2 diabetes mellitus, and hypertriglyceridemia often manifest together as the metabolic syndrome (MetS). Despite major advances in our understanding of the pathogenesis of these disorders, the prevalence of the MetS continues to rise. It is becoming increasingly apparent that intermediary metabolism within the central nervous system is a major contributor to the regulation of systemic metabolism. In particular, lipid metabolism within the brain is tightly regulated to maintain neuronal structure and function and may signal nutrient status to modulate metabolism in key peripheral tissues such as the liver. There is now a growing body of evidence to suggest that fatty acid (FA) sensing in hypothalamic neurons via accumulation of FAs or FA metabolites may signal nutritional sufficiency and may decrease hepatic glucose production, lipogenesis, and VLDL-TG secretion. In addition, recent studies have highlighted the existence of liver-related neurons that have the potential to direct such signals through parasympathetic and sympathetic nervous system activity. However, to date whether these liver-related neurons are FA sensitive remain to be determined. The findings discussed in this review underscore the importance of the autonomic nervous system in the regulation of systemic metabolism and highlight the need for further research to determine the key features of FA neurons, which may serve as novel therapeutic targets for the treatment of metabolic disorders.
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Affiliation(s)
- Kimberley D. Bruce
- University of Colorado School of Medicine, Division of Endocrinology, Metabolism and Diabetes, Aurora, CO, USA
- *Correspondence: Kimberley D. Bruce,
| | - Andrea Zsombok
- Department of Physiology, School of Medicine, Tulane University, New Orleans, LA, USA
| | - Robert H. Eckel
- University of Colorado School of Medicine, Division of Endocrinology, Metabolism and Diabetes, Aurora, CO, USA
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22
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Li L, de La Serre CB, Zhang N, Yang L, Li H, Bi S. Knockdown of Neuropeptide Y in the Dorsomedial Hypothalamus Promotes Hepatic Insulin Sensitivity in Male Rats. Endocrinology 2016; 157:4842-4852. [PMID: 27805869 PMCID: PMC5133343 DOI: 10.1210/en.2016-1662] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Recent evidence has shown that alterations in dorsomedial hypothalamic (DMH) neuropeptide Y (NPY) signaling influence glucose homeostasis, but the mechanism through which DMH NPY acts to affect glucose homeostasis remains unclear. Here we report that DMH NPY descending signals to the dorsal motor nucleus of the vagus (DMV) modulate hepatic insulin sensitivity to control hepatic glucose production in rats. Using the hyperinsulinemic-euglycemic clamp, we revealed that knockdown of NPY in the DMH by adeno-associated virus-mediated NPY-specific RNAi promoted insulin's action on suppression of hepatic glucose production. This knockdown silenced DMH NPY descending signals to the DMV, leading to an elevation of hepatic vagal innervation. Hepatic vagotomy abolished the inhibitory effect of DMH NPY knockdown on hepatic glucose production, but this glycemic effect was not affected by vagal deafferentation. Together, these results demonstrate a distinct role for DMH NPY in the regulation of glucose homeostasis through the hepatic vagal efferents and insulin action on hepatic glucose production.
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Affiliation(s)
- Lin Li
- Department of Psychiatry and Behavioral Sciences (L.L., C.B.d.L.S., N.Z., L.Y., S.B.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; and Department of Endocrinology (L.L., H.L.), The Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
| | - C Barbier de La Serre
- Department of Psychiatry and Behavioral Sciences (L.L., C.B.d.L.S., N.Z., L.Y., S.B.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; and Department of Endocrinology (L.L., H.L.), The Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
| | - Ni Zhang
- Department of Psychiatry and Behavioral Sciences (L.L., C.B.d.L.S., N.Z., L.Y., S.B.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; and Department of Endocrinology (L.L., H.L.), The Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
| | - Liang Yang
- Department of Psychiatry and Behavioral Sciences (L.L., C.B.d.L.S., N.Z., L.Y., S.B.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; and Department of Endocrinology (L.L., H.L.), The Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
| | - Hong Li
- Department of Psychiatry and Behavioral Sciences (L.L., C.B.d.L.S., N.Z., L.Y., S.B.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; and Department of Endocrinology (L.L., H.L.), The Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
| | - Sheng Bi
- Department of Psychiatry and Behavioral Sciences (L.L., C.B.d.L.S., N.Z., L.Y., S.B.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; and Department of Endocrinology (L.L., H.L.), The Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, China
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Imbernon M, Sanchez‐Rebordelo E, Romero‐Picó A, Kalló I, Chee MJ, Porteiro B, Al‐Massadi O, Contreras C, Fernø J, Senra A, Gallego R, Folgueira C, Seoane LM, van Gestel M, Adan RA, Liposits Z, Dieguez C, López M, Nogueiras R. Hypothalamic kappa opioid receptor mediates both diet-induced and melanin concentrating hormone-induced liver damage through inflammation and endoplasmic reticulum stress. Hepatology 2016; 64:1086-104. [PMID: 27387967 PMCID: PMC5129461 DOI: 10.1002/hep.28716] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 07/05/2016] [Indexed: 12/14/2022]
Abstract
UNLABELLED The opioid system is widely known to modulate the brain reward system and thus affect the behavior of humans and other animals, including feeding. We hypothesized that the hypothalamic opioid system might also control energy metabolism in peripheral tissues. Mice lacking the kappa opioid receptor (κOR) and adenoviral vectors overexpressing or silencing κOR were stereotaxically delivered in the lateral hypothalamic area (LHA) of rats. Vagal denervation was performed to assess its effect on liver metabolism. Endoplasmic reticulum (ER) stress was inhibited by pharmacological (tauroursodeoxycholic acid) and genetic (overexpression of the chaperone glucose-regulated protein 78 kDa) approaches. The peripheral effects on lipid metabolism were assessed by histological techniques and western blot. We show that in the LHA κOR directly controls hepatic lipid metabolism through the parasympathetic nervous system, independent of changes in food intake and body weight. κOR colocalizes with melanin concentrating hormone receptor 1 (MCH-R1) in the LHA, and genetic disruption of κOR reduced melanin concentrating hormone-induced liver steatosis. The functional relevance of these findings was given by the fact that silencing of κOR in the LHA attenuated both methionine choline-deficient, diet-induced and choline-deficient, high-fat diet-induced ER stress, inflammation, steatohepatitis, and fibrosis, whereas overexpression of κOR in this area promoted liver steatosis. Overexpression of glucose-regulated protein 78 kDa in the liver abolished hypothalamic κOR-induced steatosis by reducing hepatic ER stress. CONCLUSIONS This study reveals a novel hypothalamic-parasympathetic circuit modulating hepatic function through inflammation and ER stress independent of changes in food intake or body weight; these findings might have implications for the clinical use of opioid receptor antagonists. (Hepatology 2016;64:1086-1104).
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Affiliation(s)
- Monica Imbernon
- Department of PhysiologyCIMUS, University of Santiago de Compostela‐Instituto de Investigación Sanitaria,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn)Santiago de CompostelaSpain
| | - Estrella Sanchez‐Rebordelo
- Department of PhysiologyCIMUS, University of Santiago de Compostela‐Instituto de Investigación Sanitaria,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn)Santiago de CompostelaSpain
| | - Amparo Romero‐Picó
- Department of PhysiologyCIMUS, University of Santiago de Compostela‐Instituto de Investigación Sanitaria,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn)Santiago de CompostelaSpain
| | - Imre Kalló
- Laboratory of Endocrine NeurobiologyInstitute of Experimental Medicine, Hungarian Academy of SciencesBudapestHungary
| | - Melissa J. Chee
- Division of Endocrinology, Department of MedicineBeth Israel Deaconess Medical Center, Harvard Medical SchoolBostonMA
| | - Begoña Porteiro
- Department of PhysiologyCIMUS, University of Santiago de Compostela‐Instituto de Investigación Sanitaria,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn)Santiago de CompostelaSpain
| | - Omar Al‐Massadi
- Department of PhysiologyCIMUS, University of Santiago de Compostela‐Instituto de Investigación Sanitaria,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn)Santiago de CompostelaSpain
| | - Cristina Contreras
- Department of PhysiologyCIMUS, University of Santiago de Compostela‐Instituto de Investigación Sanitaria,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn)Santiago de CompostelaSpain
| | - Johan Fernø
- Department of Clinical ScienceKG Jebsen Center for Diabetes Research, University of BergenBergenNorway
| | - Ana Senra
- Department of PhysiologyCIMUS, University of Santiago de Compostela‐Instituto de Investigación Sanitaria,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn)Santiago de CompostelaSpain
| | - Rosalia Gallego
- Department of Morphological Sciences, School of MedicineUniversity of Santiago de Compostela‐Instituto de Investigación Sanitaria
| | - Cintia Folgueira
- Department of PhysiologyCIMUS, University of Santiago de Compostela‐Instituto de Investigación Sanitaria,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn)Santiago de CompostelaSpain,Grupo Fisiopatología Endocrina, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo, Hospitalario Universitario de Santiago (CHUS/SERGAS)Santiago de CompostelaSpain
| | - Luisa M. Seoane
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn)Santiago de CompostelaSpain,Grupo Fisiopatología Endocrina, Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo, Hospitalario Universitario de Santiago (CHUS/SERGAS)Santiago de CompostelaSpain
| | - Margriet van Gestel
- Department of Neuroscience and PharmacologyRudolf Magnus Institute of Neuroscience, University Medical Center UtrechtUtrechtThe Netherlands
| | - Roger A. Adan
- Department of Neuroscience and PharmacologyRudolf Magnus Institute of Neuroscience, University Medical Center UtrechtUtrechtThe Netherlands
| | - Zsolt Liposits
- Laboratory of Endocrine NeurobiologyInstitute of Experimental Medicine, Hungarian Academy of SciencesBudapestHungary
| | - Carlos Dieguez
- Department of PhysiologyCIMUS, University of Santiago de Compostela‐Instituto de Investigación Sanitaria,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn)Santiago de CompostelaSpain
| | - Miguel López
- Department of PhysiologyCIMUS, University of Santiago de Compostela‐Instituto de Investigación Sanitaria,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn)Santiago de CompostelaSpain
| | - Ruben Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria. .,CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain.
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Arsenijevic D, Cajot JF, Fellay B, Dulloo AG, Van Vliet BN, Montani JP. Uninephrectomy-Induced Lipolysis and Low-Grade Inflammation Are Mimicked by Unilateral Renal Denervation. Front Physiol 2016; 7:227. [PMID: 27378937 PMCID: PMC4906570 DOI: 10.3389/fphys.2016.00227] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/30/2016] [Indexed: 12/13/2022] Open
Abstract
Uninephrectomy (UniNX) in rats on a fixed food intake leads to increased lipolysis and a low-grade inflammation with an increased subset of circulating cytokines. Because UniNX ablates renal nerves on the side of the removed kidney, we tested the contribution of unilateral renal denervation in the phenotype of UniNX. We compared Sham-operated controls, left nephrectomy (UniNX) and unilateral left kidney denervation (uDNX) in rats 4 weeks after surgery. uDNX did not affect kidney weight and function. In general, the uDNX phenotype was similar to the UniNX phenotype especially for lipolysis in fat pads and increased low-grade inflammation. uDNX led to decreased fat pad weight and increased hormone sensitive lipase and adipocyte triglyceride lipase mRNA levels in epididymal and inguinal adipose tissue, as well as increased circulating lipolysis markers β-hydroxybutyrate and glycerol. Measured circulating hormones such as leptin, T3 and insulin were similar amongst the three groups. The lipolytic cytokines interferon-gamma and granulocyte macrophage colony stimulating factor were increased in the circulation of both uDNX and UniNX groups. These two cytokines were also elevated in the spleen of both groups, but contrastingly they were decreased in fat pads, liver, and kidneys. Both uDNX and UniNX similarly increased noradrenaline content in fat pads and spleen. Melanocortin 4 receptor mRNA levels were increased in the brains of both uDNX and UniNX compared to Sham and may contribute to increased tissue noradrenaline levels. In addition, the farnesoid x receptor (FXR) may contribute to changes in tissue metabolism and inflammation, as anti-inflammatory FXR was decreased in the spleen but increased in other tissues in uDNX and UniNX compared to Sham. In summary, both uDNX and UniNX in rats promote metabolic and immunological alterations by mechanisms that seem to implicate modification of unilateral renal nerve pathways as well as central and peripheral neural pathways.
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Affiliation(s)
- Denis Arsenijevic
- Division of Physiology, Department of Medicine, University of FribourgFribourg, Switzerland; National Center of Competence in Research (Kidney.CH)Zurich, Switzerland
| | - Jean-François Cajot
- Division of Physiology, Department of Medicine, University of Fribourg Fribourg, Switzerland
| | - Benoit Fellay
- Chemistry/Hematology Laboratory, Fribourg Hospital Fribourg, Switzerland
| | - Abdul G Dulloo
- Division of Physiology, Department of Medicine, University of Fribourg Fribourg, Switzerland
| | - Bruce N Van Vliet
- BioMedical Sciences Division, Faculty of Medicine, Memorial University St. John's, NL, Canada
| | - Jean-Pierre Montani
- Division of Physiology, Department of Medicine, University of FribourgFribourg, Switzerland; National Center of Competence in Research (Kidney.CH)Zurich, Switzerland
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25
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O'Hare JD, Zsombok A. Brain-liver connections: role of the preautonomic PVN neurons. Am J Physiol Endocrinol Metab 2016; 310:E183-9. [PMID: 26646097 PMCID: PMC4838125 DOI: 10.1152/ajpendo.00302.2015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 12/01/2015] [Indexed: 12/28/2022]
Abstract
Diabetes mellitus and the coexisting conditions and complications, including hypo- and hyperglycemic events, obesity, high cholesterol levels, and many more, are devastating problems. Undoubtedly, there is a huge demand for treatment and prevention of these conditions that justifies the search for new approaches and concepts for better management of whole body metabolism. Emerging evidence demonstrates that the autonomic nervous system is largely involved in the regulation of glucose homeostasis; however, the underlying mechanisms are still under investigation. Within the hypothalamus, the paraventricular nucleus (PVN) is in a unique position to integrate neural and hormonal signals to command both the autonomic and neuroendocrine outflow. This minireview will provide a brief overview on the role of preautonomic PVN neurons and the importance of the PVN-liver pathway in the regulation of glucose homeostasis.
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Affiliation(s)
- James D O'Hare
- Department of Physiology, School of Medicine, Tulane University, New Orleans, Louisiana
| | - Andrea Zsombok
- Department of Physiology, School of Medicine, Tulane University, New Orleans, Louisiana
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26
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Kandilis AN, Papadopoulou IP, Koskinas J, Sotiropoulos G, Tiniakos DG. Liver innervation and hepatic function: new insights. J Surg Res 2015; 194:511-519. [DOI: 10.1016/j.jss.2014.12.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 11/04/2014] [Accepted: 12/03/2014] [Indexed: 12/14/2022]
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Abstract
Obesity rates continue to rise throughout the world. Recent evidence has suggested that environmental factors contribute to altered energy balance regulation. However, the role of epigenetic modifications to the central control of energy homeostasis remains unknown. To investigate the role of DNA methylation in the regulation of energy balance, we investigated the role of the de novo DNA methyltransferase, Dnmt3a, in Single-minded 1 (Sim1) cells, including neurons in the paraventricular nucleus of the hypothalamus (PVH). Dnmt3a expression levels were decreased in the PVH of high-fat-fed mice. Mice lacking Dnmt3a specifically in the Sim1 neurons, which are expressed in the forebrain, including PVH, became obese with increased amounts of abdominal and subcutaneous fat. The mice were also found to have hyperphagia, decreased energy expenditure, and glucose intolerance with increased serum insulin and leptin. Furthermore, these mice developed hyper-LDL cholesterolemia when fed a high-fat diet. Gene expression profiling and DNA methylation analysis revealed that the expression of tyrosine hydroxylase and galanin were highly upregulated in the PVH of Sim1-specific Dnmt3a deletion mice. DNA methylation levels of the tyrosine hydroxylase promoter were decreased in the PVH of the deletion mice. These results suggest that Dnmt3a in the PVH is necessary for the normal control of body weight and energy homeostasis and that tyrosine hydroxylase is a putative target of Dnmt3a in the PVH. These results provide evidence for a role for Dnmt3a in the PVH to link environmental conditions to altered energy homeostasis.
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28
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Kosse C, Gonzalez A, Burdakov D. Predictive models of glucose control: roles for glucose-sensing neurones. Acta Physiol (Oxf) 2015; 213:7-18. [PMID: 25131833 PMCID: PMC5767106 DOI: 10.1111/apha.12360] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/08/2014] [Accepted: 08/01/2014] [Indexed: 12/17/2022]
Abstract
The brain can be viewed as a sophisticated control module for stabilizing blood glucose. A review of classical behavioural evidence indicates that central circuits add predictive (feedforward/anticipatory) control to the reactive (feedback/compensatory) control by peripheral organs. The brain/cephalic control is constructed and engaged, via associative learning, by sensory cues predicting energy intake or expenditure (e.g. sight, smell, taste, sound). This allows rapidly measurable sensory information (rather than slowly generated internal feedback signals, e.g. digested nutrients) to control food selection, glucose supply for fight-or-flight responses or preparedness for digestion/absorption. Predictive control is therefore useful for preventing large glucose fluctuations. We review emerging roles in predictive control of two classes of widely projecting hypothalamic neurones, orexin/hypocretin (ORX) and melanin-concentrating hormone (MCH) cells. Evidence is cited that ORX neurones (i) are activated by sensory cues (e.g. taste, sound), (ii) drive hepatic production, and muscle uptake, of glucose, via sympathetic nerves, (iii) stimulate wakefulness and exploration via global brain projections and (iv) are glucose-inhibited. MCH neurones are (i) glucose-excited, (ii) innervate learning and reward centres to promote synaptic plasticity, learning and memory and (iii) are critical for learning associations useful for predictive control (e.g. using taste to predict nutrient value of food). This evidence is unified into a model for predictive glucose control. During associative learning, inputs from some glucose-excited neurones may promote connections between the 'fast' senses and reward circuits, constructing neural shortcuts for efficient action selection. In turn, glucose-inhibited neurones may engage locomotion/exploration and coordinate the required fuel supply. Feedback inhibition of the latter neurones by glucose would ensure that glucose fluxes they stimulate (from liver, into muscle) are balanced. Estimating nutrient challenges from indirect sensory cues may become more difficult when the cues become complex and variable (e.g. like human foods today). Consequent errors of predictive glucose control may contribute to obesity and diabetes.
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Affiliation(s)
- C. Kosse
- Division of Neurophysiology MRC National Institute for Medical Research London UK
| | - A. Gonzalez
- Division of Neurophysiology MRC National Institute for Medical Research London UK
| | - D. Burdakov
- Division of Neurophysiology MRC National Institute for Medical Research London UK
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29
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de Vries EM, Eggels L, van Beeren HC, Ackermans MT, Kalsbeek A, Fliers E, Boelen A. Fasting-induced changes in hepatic thyroid hormone metabolism in male rats are independent of autonomic nervous input to the liver. Endocrinology 2014; 155:5033-41. [PMID: 25243858 DOI: 10.1210/en.2014-1608] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
During fasting, profound changes in the regulation of the hypothalamus-pituitary-thyroid axis occur in order to save energy and limit catabolism. In this setting, serum T3 and T4 are decreased without an appropriate TSH and TRH response reflecting central down-regulation of the hypothalamus-pituitary-thyroid axis. Hepatic thyroid hormone (TH) metabolism is also affected by fasting, because type 3 deiodinase (D3) is increased, which is mediated by serum leptin concentrations. A recent study showed that fasting-induced changes in liver TH sulfotransferases (Sults) and uridine 5'-diphospho-glucuronosyltransferase (Ugts) depend on a functional melanocortin system in the hypothalamus. However, the pathways connecting the hypothalamus and the liver that induce these changes are currently unknown. In the present study, we investigated in rats whether the fasting-induced changes in hepatic TH metabolism are regulated by the autonomic nervous system. We selectively cut either the sympathetic or the parasympathetic input to the liver. Serum and liver TH concentrations, deiodinase expression, and activity and Sult and Ugt expression were measured in rats that had been fasted for 36 hours or were fed ad libitum. Fasting decreased serum T3 and T4 concentrations, whereas intrahepatic TH concentrations remained unchanged. D3 expression and activity increased, as was the expression of constitutive androstane receptor, Sult1b1, and Ugt1a1, whereas liver D1 was unaffected. Neither sympathetic nor parasympathetic denervation affected the fasting-induced alterations. We conclude that fasting-induced changes in liver TH metabolism are not regulated via the hepatic autonomic input in a major way and more likely reflect a direct effect of humoral factors on the hepatocyte.
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Affiliation(s)
- E M de Vries
- Department of Endocrinology and Metabolism (E.M.d.V., L.E., H.C.B., A.K., E.F., A.B.), Academic Medical Center, University of Amsterdam, 1105AZ The Netherlands; Hypothalamic Integration Mechanisms (A.K.), Netherlands Institute for Neuroscience, Amsterdam, 1105BA The Netherlands; and Department of Clinical Chemistry (M.T.A.), Laboratory of Endocrinology, Academic Medical Center, University of Amsterdam, 1105AZ The Netherlands
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Liu TT, Ding TL, Ma Y, Wei W. Selective α1B- and α1D-adrenoceptor antagonists suppress noradrenaline-induced activation, proliferation and ECM secretion of rat hepatic stellate cells in vitro. Acta Pharmacol Sin 2014; 35:1385-92. [PMID: 25283507 DOI: 10.1038/aps.2014.84] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 07/07/2014] [Indexed: 12/11/2022] Open
Abstract
AIM To explore the effects of noradrenaline (NA) on hepatic stellate cells (HSCs) in vitro and to determine the adrenoceptor (AR) subtypes and underlying mechanisms. METHODS The distribution and expressions of α1A-, α1B-, and α1D-ARs in HSC-T6 cells were analyzed using immunocytochemistry and RT-PCR. Cell proliferation was evaluated with MTT assay. The expression of HSC activation factors [transforming factor-β1 (TGF-β1) and α-smooth muscle actin (α-SMA)], extracellular matrix (ECM) secretion factors [tissue inhibitor of metalloproteinase-1 (TIMP-1) and collagen-Ι (ColΙ)] and PKC-PI3K-AKT signaling components (PKC, PI3K, and AKT) in the cells were detected by Western blotting and RT-PCR. RESULTS Both α1B- and α1D-AR were expressed in the membrane of HSC-T6 cells, whereas α1A-AR was not detected. Treatment of the cells with NA concentration-dependently increased cell proliferation (EC50=277 nmol/L), which was suppressed by the α1B-AR antagonist CEC or by the α1D-AR antagonist BMY7378. Furthermore, NA (0.001, 0.1, and 10 μmol/L) concentration-dependently increased the expression of TGF-β1, α-SMA, TIMP-1 and ColΙ, PKC and PI3K, and phosphorylation of AKT in HSC-T6 cells, which were suppressed by CEC or BMY7378, or by pertussis toxin (PT), RO-32-0432 (PKC antagonist), LY294002 (PI3K antagonist) or GSK690693 (AKT antagonist). CONCLUSION NA promotes HSC-T6 cell activation, proliferation and secretion of ECM in vitro via activation of Gα-coupled α1B-AR and α1D-AR and the PKC-PI3K-AKT signaling pathway.
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Yokota SI, Nakamura K, Ando M, Kamei H, Hakuno F, Takahashi SI, Shibata S. Acetylcholinesterase (AChE) inhibition aggravates fasting-induced triglyceride accumulation in the mouse liver. FEBS Open Bio 2014; 4:905-14. [PMID: 25383314 PMCID: PMC4223152 DOI: 10.1016/j.fob.2014.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 10/13/2014] [Accepted: 10/16/2014] [Indexed: 12/11/2022] Open
Abstract
Although fasting induces hepatic triglyceride (TG) accumulation in both rodents and humans, little is known about the underlying mechanism. Because parasympathetic nervous system activity tends to attenuate the secretion of very-low-density-lipoprotein-triglyceride (VLDL-TG) and increase TG stores in the liver, and serum cholinesterase activity is elevated in fatty liver disease, the inhibition of the parasympathetic neurotransmitter acetylcholinesterase (AChE) may have some influence on hepatic lipid metabolism. To assess the influence of AChE inhibition on lipid metabolism, the effect of physostigmine, an AChE inhibitor, on fasting-induced increase in liver TG was investigated in mice. In comparison with ad libitum-fed mice, 30 h fasting increased liver TG accumulation accompanied by a downregulation of sterol regulatory element-binding protein 1 (SREBP-1) and liver-fatty acid binding-protein (L-FABP). Physostigmine promoted the 30 h fasting-induced increase in liver TG levels in a dose-dependent manner, accompanied by a significant fall in plasma insulin levels, without a fall in plasma TG. Furthermore, physostigmine significantly attenuated the fasting-induced decrease of both mRNA and protein levels of SREBP-1 and L-FABP, and increased IRS-2 protein levels in the liver. The muscarinic receptor antagonist atropine blocked these effects of physostigmine on liver TG, serum insulin, and hepatic protein levels of SREBP-1 and L-FABP. These results demonstrate that AChE inhibition facilitated fasting-induced TG accumulation with up regulation of the hepatic L-FABP and SREBP-1 in mice, at least in part via the activation of muscarinic acetylcholine receptors. Our studies highlight the crucial role of parasympathetic regulation in fasting-induced TG accumulation, and may be an important source of information on the mechanism of hepatic disorders of lipid metabolism.
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Key Words
- ACC, acetyl coenzyme-A carboxylase
- ACh, acetylcholine
- AChE, acetylcholinesterase
- CPT-1, carnitine palmitoyltransferase 1
- FA, fatty acid(s)
- FAS, fatty acid synthase
- Fatty liver
- IRS-2, insulin receptor substrate
- L-FABP, liver fatty acid-binding protein
- Lipogenesis
- Lipolysis
- Metabolic syndrome
- PEPCK, phosphoenolpyruvate carboxykinase
- PGC-1α, peroxisome proliferator activated receptor gamma coactivator 1-alpha
- PPAR-α, peroxisome proliferator activated receptor alpha
- Parasympathetic nerve
- SREBP, sterol regulatory element binding proteins
- TG, triglyceride(s)
- Triglyceride
- VLDL, very low-density lipoprotein(s)
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Affiliation(s)
- Shin-Ichi Yokota
- Department of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan ; Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Tokyo, Japan
| | - Kaai Nakamura
- Department of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Midori Ando
- Department of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Hiroyasu Kamei
- Department of Animal Sciences and Applied Biological Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Fumihiko Hakuno
- Department of Animal Sciences and Applied Biological Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Shin-Ichiro Takahashi
- Department of Animal Sciences and Applied Biological Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Shigenobu Shibata
- Department of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
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Ontogenic development of nerve fibers in human fetal livers: an immunohistochemical study using neural cell adhesion molecule (NCAM) and neuron-specific enolase (NSE). Histochem Cell Biol 2014; 143:421-9. [PMID: 25326085 DOI: 10.1007/s00418-014-1286-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2014] [Indexed: 01/03/2023]
Abstract
The aim of the study was to investigate nerve fibers (NF) in human fetal livers. An immunohistochemical study was performed. NF were classified into portal tract innervation (PoI) and parenchymal innervation (PaI). The hilum area showed many Pol NF at 7 GW, and NF increased with gestational week (GW). Direct innervations to biliary epithelium were recognized. In large portal tracts, a few NCAM-positive mesenchymal cells were seen at 8 GW and many mesenchymal cells were noted around 12 GW. Apparent NF emerged around 15 GW, and NF increased with GW. Many NF plexuses were seen in 30-40 GW. In small portal tracts, no NF were seen in 7-10 GW. A few NCAM-positive mesenchymal cells emerged in 11 GW, and they increased thereafter. Apparent NF were seen around 20 GW and NF increased with GW. At term (40 GW), PoI NF were still immature. Ductal plate (DP) was positive for NCAM, NSE, chromogranin and synaptophysin, and direct innervations to DP were seen. The direct innervations to developing bile ducts and peribiliary glands were also seen. PaI NF were first seen at 21 GW and was consistent until 40 GW in which a few NF were seen in PaI. These observations suggest that PoI NF arise from committed portal mesenchyme. PaI NF are very immature at 40 GW. There are direct innervations to bile ducts, peribiliary glands, portal veins, hepatic arteries, and DP.
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Fernandes AL, Lopes-Silva JP, Bertuzzi R, Casarini DE, Arita DY, Bishop DJ, Lima-Silva AE. Effect of time of day on performance, hormonal and metabolic response during a 1000-M cycling time trial. PLoS One 2014; 9:e109954. [PMID: 25289885 PMCID: PMC4188634 DOI: 10.1371/journal.pone.0109954] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 09/12/2014] [Indexed: 11/30/2022] Open
Abstract
The aim of this study was to determine the effect of time of day on performance, pacing, and hormonal and metabolic responses during a 1000-m cycling time-trial. Nine male, recreational cyclists visited the laboratory four times. During the 1st visit the participants performed an incremental test and during the 2nd visit they performed a 1000-m cycling familiarization trial. On the 3rd and 4th visits, the participants performed a 1000-m TT at either 8 am or 6 pm, in randomized, repeated-measures, crossover design. The time to complete the time trial was lower in the evening than in the morning (88.2±8.7 versus 94.7±10.9 s, respectively, p<0.05), but there was no significant different in pacing. However, oxygen uptake and aerobic mechanical power output at 600 and 1000 m tended to be higher in the evening (p<0.07 and 0.09, respectively). There was also a main effect of time of day for insulin, cortisol, and total and free testosterone concentration, which were all higher in the morning (+60%, +26%, +31% and +22%, respectively, p<0.05). The growth hormone, was twofold higher in the evening (p<0.05). The plasma glucose was ∼11% lower in the morning (p<0.05). Glucagon, norepinephrine, epinephrine and lactate were similar for the morning and evening trials (p>0.05), but the norepinephrine response to the exercise was increased in the morning (+46%, p<0.05), and it was accompanied by a 5-fold increase in the response of glucose. Muscle recruitment, as measured by electromyography, was similar between morning and evening trials (p>0.05). Our findings suggest that performance was improved in the evening, and it was accompanied by an improved hormonal and metabolic milieu.
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Affiliation(s)
- Alan Lins Fernandes
- Sports Science Research Group, Federal University of Alagoas, Maceio, Alagoas, Brazil, and Department of Physical Education and Sports Science, CAV, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
| | - João Paulo Lopes-Silva
- Sports Science Research Group, Federal University of Alagoas, Maceio, Alagoas, Brazil, and Department of Physical Education and Sports Science, CAV, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
| | - Rômulo Bertuzzi
- Endurance Performance Research Group, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Dulce Elena Casarini
- Nephrology Division, Department of Medicine, Federal University of Sao Paulo, São Paulo, Brazil
| | - Danielle Yuri Arita
- Nephrology Division, Department of Medicine, Federal University of Sao Paulo, São Paulo, Brazil
| | - David John Bishop
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Australia
| | - Adriano Eduardo Lima-Silva
- Sports Science Research Group, Federal University of Alagoas, Maceio, Alagoas, Brazil, and Department of Physical Education and Sports Science, CAV, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
- * E-mail:
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Bruinstroop E, Fliers E, Kalsbeek A. Hypothalamic control of hepatic lipid metabolism via the autonomic nervous system. Best Pract Res Clin Endocrinol Metab 2014; 28:673-84. [PMID: 25256763 DOI: 10.1016/j.beem.2014.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Our body is well designed to store energy in times of nutrient excess, and release energy in times of food deprivation. This adaptation to the external environment is achieved by humoral factors and the autonomic nervous system. Claude Bernard, in the 19th century, showed the importance of the autonomic nervous system in the control of glucose metabolism. In the 20th century, the discovery of insulin and the development of techniques to measure hormone concentrations shifted the focus from the neural control of metabolism to the secretion of hormones, thus functionally "decapitating" the body. Just before the end of the 20th century, starting with the discovery of leptin in 1994, the control of energy metabolism went back to our heads. Since the start of 21st century, numerous studies have reported the involvement of hypothalamic pathways in the control of hepatic insulin sensitivity and glucose production. The autonomic nervous system is, therefore, acknowledged to be one of the important determinants of liver metabolism and a possible treatment target. In this chapter, we review research to date on the hypothalamic control of hepatic lipid metabolism.
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Affiliation(s)
- Eveline Bruinstroop
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands.
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Kalsbeek A, la Fleur S, Fliers E. Circadian control of glucose metabolism. Mol Metab 2014; 3:372-83. [PMID: 24944897 PMCID: PMC4060304 DOI: 10.1016/j.molmet.2014.03.002] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 03/05/2014] [Accepted: 03/07/2014] [Indexed: 01/15/2023] Open
Abstract
The incidence of obesity and type 2 diabetes mellitus (T2DM) has risen to epidemic proportions. The pathophysiology of T2DM is complex and involves insulin resistance, pancreatic β-cell dysfunction and visceral adiposity. It has been known for decades that a disruption of biological rhythms (which happens the most profoundly with shift work) increases the risk of developing obesity and T2DM. Recent evidence from basal studies has further sparked interest in the involvement of daily rhythms (and their disruption) in the development of obesity and T2DM. Most living organisms have molecular clocks in almost every tissue, which govern rhythmicity in many domains of physiology, such as rest/activity rhythms, feeding/fasting rhythms, and hormonal secretion. Here we present the latest research describing the specific role played by the molecular clock mechanism in the control of glucose metabolism and speculate on how disruption of these tissue clocks may lead to the disturbances in glucose homeostasis.
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Affiliation(s)
- Andries Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, The Netherlands ; Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Susanne la Fleur
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, The Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, The Netherlands
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Attig L, Vigé A, Gabory A, Karimi M, Beauger A, Gross MS, Athias A, Gallou-Kabani C, Gambert P, Ekstrom TJ, Jais JP, Junien C. Dietary alleviation of maternal obesity and diabetes: increased resistance to diet-induced obesity transcriptional and epigenetic signatures. PLoS One 2013; 8:e66816. [PMID: 23826145 PMCID: PMC3691260 DOI: 10.1371/journal.pone.0066816] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Accepted: 05/15/2013] [Indexed: 02/07/2023] Open
Abstract
According to the developmental origins of health and diseases (DOHaD), and in line with the findings of many studies, obesity during pregnancy is clearly a threat to the health and well-being of the offspring, later in adulthood. We previously showed that 20% of male and female inbred mice can cope with the obesogenic effects of a high-fat diet (HFD) for 20 weeks after weaning, remaining lean. However the feeding of a control diet (CD) to DIO mice during the periconceptional/gestation/lactation period led to a pronounced sex-specific shift (17% to 43%) from susceptibility to resistance to HFD, in the female offspring only. Our aim in this study was to determine how, in the context of maternal obesity and T2D, a CD could increase resistance on female fetuses. Transcriptional analyses were carried out with a custom-built mouse liver microarray and by quantitative RT-PCR for muscle and adipose tissue. Both global DNA methylation and levels of pertinent histone marks were assessed by LUMA and western blotting, and the expression of 15 relevant genes encoding chromatin-modifying enzymes was analyzed in tissues presenting global epigenetic changes. Resistance was associated with an enhancement of hepatic pathways protecting against steatosis, the unexpected upregulation of neurotransmission-related genes and the modulation of a vast imprinted gene network. Adipose tissue displayed a pronounced dysregulation of gene expression, with an upregulation of genes involved in lipid storage and adipocyte hypertrophy or hyperplasia in obese mice born to lean and obese mothers, respectively. Global DNA methylation, several histone marks and key epigenetic regulators were also altered. Whether they were themselves lean (resistant) or obese (sensitive), the offspring of lean and obese mice clearly differed in terms of several metabolic features and epigenetic marks suggesting that the effects of a HFD depend on the leanness or obesity of the mother.
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Affiliation(s)
- Linda Attig
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- INSERM U781 AP-HP; Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants, Paris, France
| | - Alexandre Vigé
- INSERM U781 AP-HP; Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants, Paris, France
| | - Anne Gabory
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- INSERM U781 AP-HP; Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants, Paris, France
| | - Moshen Karimi
- Laboratory for Medical Epigenetics, Center for Molecular Medicine, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Aurore Beauger
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- INSERM U781 AP-HP; Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants, Paris, France
| | - Marie-Sylvie Gross
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- INSERM U781 AP-HP; Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants, Paris, France
| | - Anne Athias
- IFR100 Santé-STIC, Plateau Technique Lipidomique, CHU Bocage Bat B2, Dijon, France
| | - Catherine Gallou-Kabani
- INSERM U781 AP-HP; Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants, Paris, France
| | - Philippe Gambert
- IFR100 Santé-STIC, Laboratoire de Biochimie Médicale, Plateau Technique de Biologie, Dijon, France
| | - Tomas J. Ekstrom
- Laboratory for Medical Epigenetics, Center for Molecular Medicine, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Jean-Philippe Jais
- Service de Biostatistique et Informatique Médicale, Université Paris Descartes, Hôpital Necker-Enfants Malades, Paris, France
| | - Claudine Junien
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
- INSERM U781 AP-HP; Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants, Paris, France
- Laboratory for Medical Epigenetics, Center for Molecular Medicine, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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Bruinstroop E, la Fleur SE, Ackermans MT, Foppen E, Wortel J, Kooijman S, Berbée JFP, Rensen PCN, Fliers E, Kalsbeek A. The autonomic nervous system regulates postprandial hepatic lipid metabolism. Am J Physiol Endocrinol Metab 2013; 304:E1089-96. [PMID: 23531617 DOI: 10.1152/ajpendo.00614.2012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The liver is a key organ in controlling glucose and lipid metabolism during feeding and fasting. In addition to hormones and nutrients, inputs from the autonomic nervous system are also involved in fine-tuning hepatic metabolic regulation. Previously, we have shown in rats that during fasting an intact sympathetic innervation of the liver is essential to maintain the secretion of triglycerides by the liver. In the current study, we hypothesized that in the postprandial condition the parasympathetic input to the liver inhibits hepatic VLDL-TG secretion. To test our hypothesis, we determined the effect of selective surgical hepatic denervations on triglyceride metabolism after a meal in male Wistar rats. We report that postprandial plasma triglyceride concentrations were significantly elevated in parasympathetically denervated rats compared with control rats (P = 0.008), and VLDL-TG production tended to be increased (P = 0.066). Sympathetically denervated rats also showed a small rise in postprandial triglyceride concentrations (P = 0.045). On the other hand, in rats fed on a six-meals-a-day schedule for several weeks, a parasympathetic denervation resulted in >70% higher plasma triglycerides during the day (P = 0.001), whereas a sympathetic denervation had no effect. Our results show that abolishing the parasympathetic input to the liver results in increased plasma triglyceride levels during postprandial conditions.
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Affiliation(s)
- Eveline Bruinstroop
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, Amsterdam, The Netherlands.
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Thayer JF, Fischer JE. Heart rate variability, overnight urinary norepinephrine, and plasma cholesterol in apparently healthy human adults. Int J Cardiol 2013; 162:240-4. [DOI: 10.1016/j.ijcard.2011.05.058] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 05/08/2011] [Accepted: 05/13/2011] [Indexed: 10/18/2022]
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Abstract
The highly coordinated output of the hypothalamic biological clock does not only govern the daily rhythm in sleep/wake (or feeding/fasting) behaviour but also has direct control over many aspects of hormone release. In fact, a significant proportion of our current understanding of the circadian clock has its roots in the study of the intimate connections between the hypothalamic clock and multiple endocrine axes. This chapter will focus on the anatomical connections used by the mammalian biological clock to enforce its endogenous rhythmicity on the rest of the body, using a number of different hormone systems as a representative example. Experimental studies have revealed a highly specialised organisation of the connections between the mammalian circadian clock neurons and neuroendocrine as well as pre-autonomic neurons in the hypothalamus. These complex connections ensure a logical coordination between behavioural, endocrine and metabolic functions that will help the organism adjust to the time of day most efficiently. For example, activation of the orexin system by the hypothalamic biological clock at the start of the active phase not only ensures that we wake up on time but also that our glucose metabolism and cardiovascular system are prepared for this increased activity. Nevertheless, it is very likely that the circadian clock present within the endocrine glands plays a significant role as well, for instance, by altering these glands' sensitivity to specific stimuli throughout the day. In this way the net result of the activity of the hypothalamic and peripheral clocks ensures an optimal endocrine adaptation of the metabolism of the organism to its time-structured environment.
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Affiliation(s)
- Andries Kalsbeek
- Department of Endocrinology and Metabolism, G2-133, Academic Medical Center of the University of Amsterdam, The Netherlands.
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Patarrão RS, Lautt WW, Afonso RA, Ribeiro RT, Fernandes AB, Boavida JM, Macedo MP. Postprandial but not fasting insulin resistance is an early identifier of dysmetabolism in overweight subjects. Can J Physiol Pharmacol 2012; 90:923-31. [DOI: 10.1139/y2012-086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The dynamic response to insulin is highly potentiated after meal ingestion, and this meal-induced insulin sensitization (MIS) in healthy subjects is dependent on cholinergic mechanisms. The main objective of this study was to test the hypothesis that the reduced response to insulin observed in moderately overweight subjects, in comparison with control lean subjects, is due to MIS impairment and not to a reduction in the direct hypoglycemic action of insulin. Both lean and overweight male subjects were recruited. Insulin sensitivity (IS) was assessed by the rapid insulin sensitivity test (RIST) performed after a 24 h fast, as well as after a standardized meal. Fasting glucose disposal was similar between lean and overweight subjects. Following the meal, glucose disposal increased more extensively in lean than overweight subjects. The insulin profiles, in both fasted and fed states, were superimposable, suggesting that the absence of a factor other than insulin is responsible for the decreased postprandial insulin sensitivity observed in overweight subjects. Our data suggest that in overweight subjects, MIS contribution is decreased, which is responsible for the postprandial impaired IS observed and is suggested to be the cause, not effect, of mild adiposity.
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Affiliation(s)
- Rita S. Patarrão
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisbon, Portugal
| | - W. Wayne Lautt
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Manitoba, Winnipeg, MB R3E OT6, Canada
| | - Ricardo A. Afonso
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisbon, Portugal
| | - Rogério T. Ribeiro
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisbon, Portugal
- APDP-ERC Portuguese Diabetes Association Education and Research Center, Rua do Salitre, 118-120, 1250-203 Lisbon, Portugal
| | - Ana B. Fernandes
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisbon, Portugal
| | - José M. Boavida
- APDP-ERC Portuguese Diabetes Association Education and Research Center, Rua do Salitre, 118-120, 1250-203 Lisbon, Portugal
| | - M. Paula Macedo
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisbon, Portugal
- APDP-ERC Portuguese Diabetes Association Education and Research Center, Rua do Salitre, 118-120, 1250-203 Lisbon, Portugal
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Barclay JL, Tsang AH, Oster H. Interaction of central and peripheral clocks in physiological regulation. PROGRESS IN BRAIN RESEARCH 2012; 199:163-181. [DOI: 10.1016/b978-0-444-59427-3.00030-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Tudhope SJ, Wang CC, Petrie JL, Potts L, Malcomson F, Kieswich J, Yaqoob MM, Arden C, Hampson LJ, Agius L. A novel mechanism for regulating hepatic glycogen synthesis involving serotonin and cyclin-dependent kinase-5. Diabetes 2012; 61:49-60. [PMID: 22106156 PMCID: PMC3237670 DOI: 10.2337/db11-0870] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Hepatic autonomic nerves regulate postprandial hepatic glucose uptake, but the signaling pathways remain unknown. We tested the hypothesis that serotonin (5-hydroxytryptamine [5-HT]) exerts stimulatory and inhibitory effects on hepatic glucose disposal. Ligands of diverse 5-HT receptors were used to identify signaling pathway(s) regulating glucose metabolism in hepatocytes. 5-HT had stimulatory and inhibitory effects on glycogen synthesis in hepatocytes mediated by 5-HT1/2A and 5-HT2B receptors, respectively. Agonists of 5-HT1/2A receptors lowered blood glucose and increased hepatic glycogen after oral glucose loading and also stimulated glycogen synthesis in freshly isolated hepatocytes with greater efficacy than 5-HT. This effect was blocked by olanzapine, an antagonist of 5-HT1/2A receptors. It was mediated by activation of phosphorylase phosphatase, inactivation of glycogen phosphorylase, and activation of glycogen synthase. Unlike insulin action, it was not associated with stimulation of glycolysis and was counteracted by cyclin-dependent kinase (cdk) inhibitors. A role for cdk5 was supported by adaptive changes in the coactivator protein p35 and by elevated glycogen synthesis during overexpression of p35/cdk5. These results support a novel mechanism for serotonin stimulation of hepatic glycogenesis involving cdk5. The opposing effects of serotonin, mediated by distinct 5-HT receptors, could explain why drugs targeting serotonin function can cause either diabetes or hypoglycemia in humans.
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Affiliation(s)
- Susan J. Tudhope
- Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, U.K
| | - Chung-Chi Wang
- Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, U.K
| | - John L. Petrie
- Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, U.K
| | - Lloyd Potts
- Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, U.K
| | - Fiona Malcomson
- Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, U.K
| | - Julius Kieswich
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, U.K
| | - Muhammad M. Yaqoob
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Queen Mary University of London, London, U.K
| | - Catherine Arden
- Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, U.K
| | - Laura J. Hampson
- Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, U.K
| | - Loranne Agius
- Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle upon Tyne, U.K
- Corresponding author: Loranne Agius,
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Kalsbeek A, Yi CX, la Fleur SE, Buijs RM, Fliers E. Suprachiasmatic nucleus and autonomic nervous system influences on awakening from sleep. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 93:91-107. [PMID: 20970002 DOI: 10.1016/s0074-7742(10)93004-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Awakening from sleep is a clear example of an event for which (biological) clocks are of great importance. We will review some major pathways the mammalian biological clock uses to ensure an efficient and coordinated wake-up process. First we show how this clock enforces daily rhythmicity onto the hypothalamo-pituitary-adrenal (HPA) axis, via projections to neuroendocrine neurons within the hypothalamus. Next we demonstrate how this brain clock controls plasma glucose concentrations, via projections to sympathetic and parasympathetic pre-autonomic neurons within the hypothalamus. Orexin neurons in the lateral hypothalamus appear to be an important hub in this awakening control network.
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Affiliation(s)
- Andries Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
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Kalsbeek A, Scheer FA, Perreau-Lenz S, La Fleur SE, Yi CX, Fliers E, Buijs RM. Circadian disruption and SCN control of energy metabolism. FEBS Lett 2011; 585:1412-26. [PMID: 21414317 DOI: 10.1016/j.febslet.2011.03.021] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 03/08/2011] [Accepted: 03/09/2011] [Indexed: 12/23/2022]
Abstract
In this review we first present the anatomical pathways used by the suprachiasmatic nuclei to enforce its rhythmicity onto the body, especially its energy homeostatic system. The experimental data show that by activating the orexin system at the start of the active phase, the biological clock not only ensures that we wake up on time, but also that our glucose metabolism and cardiovascular system are prepared for increased activity. The drawback of such a highly integrated system, however, becomes visible when our daily lives are not fully synchronized with the environment. Thus, in addition to increased physical activity and decreased intake of high-energy food, also a well-lighted and fully resonating biological clock may help to withstand the increasing "diabetogenic" pressure of today's 24/7 society.
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Affiliation(s)
- Andries Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center of the University of Amsterdam, Amsterdam, The Netherlands.
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Hepatic stellate cell (vitamin A-storing cell) and its relative--past, present and future. Cell Biol Int 2011; 34:1247-72. [PMID: 21067523 DOI: 10.1042/cbi20100321] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
HSCs (hepatic stellate cells) (also called vitamin A-storing cells, lipocytes, interstitial cells, fat-storing cells or Ito cells) exist in the space between parenchymal cells and liver sinusoidal endothelial cells of the hepatic lobule and store 50-80% of vitamin A in the whole body as retinyl palmitate in lipid droplets in the cytoplasm. In physiological conditions, these cells play pivotal roles in the regulation of vitamin A homoeostasis. In pathological conditions, such as hepatic fibrosis or liver cirrhosis, HSCs lose vitamin A and synthesize a large amount of extracellular matrix components including collagen, proteoglycan, glycosaminoglycan and adhesive glycoproteins. Morphology of these cells also changes from the star-shaped SCs (stellate cells) to that of fibroblasts or myofibroblasts. The hepatic SCs are now considered to be targets of therapy of hepatic fibrosis or liver cirrhosis. HSCs are activated by adhering to the parenchymal cells and lose stored vitamin A during hepatic regeneration. Vitamin A-storing cells exist in extrahepatic organs such as the pancreas, lungs, kidneys and intestines. Vitamin A-storing cells in the liver and extrahepatic organs form a cellular system. The research of the vitamin A-storing cells has developed and expanded vigorously. The past, present and future of the research of the vitamin A-storing cells (SCs) will be summarized and discussed in this review.
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Karnani M, Burdakov D. Multiple hypothalamic circuits sense and regulate glucose levels. Am J Physiol Regul Integr Comp Physiol 2010; 300:R47-55. [PMID: 21048078 DOI: 10.1152/ajpregu.00527.2010] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The hypothalamus monitors body energy status in part through specialized glucose sensing neurons that comprise both glucose-excited and glucose-inhibited cells. Here we discuss recent work on the elucidation of neurochemical identities and physiological significance of these hypothalamic cells, including caveats resulting from the currently imprecise functional and molecular definitions of glucose sensing and differences in glucose-sensing responses obtained with different experimental techniques. We discuss the recently observed adaptive glucose-sensing responses of orexin/hypocretin-containing neurons, which allow these cells to sense changes in glucose levels rather than its absolute concentration, as well as the glucose-sensing abilities of melanin-concentrating hormone, neuropeptide Y, and proopiomelanocortin-containing neurons and the recent data on the role of ventromedial hypothalamic steroidogenic factor-1 (SF-1)/glutamate-containing cells in glucose homeostasis. We propose a model where orexin/hypocretin and SF-1/glutamate neurons cooperate in stimulating the sympathetic outflow to the liver and pancreas to increase blood glucose, which in turn provides negative feedback inhibition to these cells. Orexin/hypocretin neurons also stimulate feeding and reward seeking and are activated by hunger and stress, thereby providing a potential link between glucose sensing and goal-oriented behavior. The cell-type-specific neuromodulatory actions of glucose in several neurochemically distinct hypothalamic circuits are thus likely to be involved in coordinating higher brain function and behavior with autonomic adjustments in blood glucose levels.
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High-fat diet results in postprandial insulin resistance that involves parasympathetic dysfunction. Br J Nutr 2010; 104:1450-9. [DOI: 10.1017/s0007114510002400] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Different diets have distinct impacts on glucose homoeostasis, for which insulin sensitivity (IS) after a meal (postprandial IS) is highly relevant. Postprandial IS depends upon hepatic parasympathetic activation and glutathione content elevation. We tested the hypothesis that postprandial IS is compromised in high-fat diet (HFD)-induced obesity. Sprague–Dawley rats were fed a standard diet (STD, n 10), 1-week HFD (n 9) or 4-week HFD (n 8). IS was tested in postprandial state using the rapid IS test (RIST) before and after the blockade of the parasympathetic nerves (atropine, 1 mg/kg); parasympathetic-dependent IS was obtained from the difference between control and post-atropine RIST. Fasting IS was also assessed in the STD-fed rats (n 4) and 4-week HFD-fed rats (n 3) using the RIST. Whole-body fat and regional fat pads were heavier in the 1-week HFD-fed rats (79·8 (se 7·9) and 23·7 (se 1·0) g, respectively) or 4-week HFD-fed rats (106·5 (se 6·1) and 30·1 (se 1·4) g, respectively) than in the STD-fed rats (32·5 (se 3·7) and 13·7 (se 1·0) g, respectively; P < 0·001). Fasted-state IS was similar between the groups studied. Postprandial IS was higher in the STD-fed rats (185·8 (se 5·6) mg glucose/kg body weight (bw)) than in both the 1-week HFD-fed rats (108·8 (se 2·9) mg glucose/kg bw; P < 0·001) and 4-week HFD-fed rats (69·3 (se 2·6) mg glucose/kg bw; P < 0·001). Parasympathetic-dependent IS was impaired in both HFD-fed groups (STD, 108·9 (se 3·9) mg glucose/kg bw; 1-week HFD, 38·6 (se 4·2) mg glucose/kg bw; 4-week HFD, 5·4 (se 1·7) mg glucose/kg bw; P < 0·001). Total (postprandial) and parasympathetic-dependent IS correlated negatively with whole-body fat (R2 0·81 and 0·87) and regional adiposity (R2 0·85 and 0·79). In conclusion, fat accumulation induced by HFD is associated with postprandial insulin resistance, but not with fasting insulin resistance. HFD-associated postprandial insulin resistance is largely mediated by impairment of parasympathetic-dependent insulin action, which correlates with adiposity.
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Identification of neuronal subpopulations that project from hypothalamus to both liver and adipose tissue polysynaptically. Proc Natl Acad Sci U S A 2010; 107:7024-9. [PMID: 20351287 DOI: 10.1073/pnas.1002790107] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The autonomic nervous system regulates fuel availability and energy storage in the liver, adipose tissue, and other organs; however, the molecular components of this neural circuit are poorly understood. We sought to identify neural populations that project from the CNS indirectly through multisynaptic pathways to liver and epididymal white fat in mice using pseudorabies virus strains expressing different reporters together with BAC transgenesis and immunohistochemistry. Neurons common to both circuits were identified in subpopulations of the paraventricular nucleus of the hypothalamus (PVH) by double labeling with markers expressed in viruses injected in both sites. The lateral hypothalamus and arcuate nucleus of the hypothalamus and brainstem regions (nucleus of the solitary tract and A5 region) also project to both tissues but are labeled at later times. Connections from these same sites to the PVH were evident after direct injection of virus into the PVH, suggesting that these regions lie upstream of the PVH in a common pathway to liver and adipose tissue (two metabolically active organs). These common populations of brainstem and hypothalamic neurons express neuropeptide Y and proopiomelanocortin in the arcuate nucleus, melanin-concentrating hormone, and orexin in the lateral hypothalamus and in the corticotrophin-releasing hormone and oxytocin in the PVH. The delineation of this circuitry will facilitate a functional analysis of the possible role of these potential command-like neurons to modulate autonomic outflow and coordinate metabolic responses in liver and adipose tissue.
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Abstract
The liver plays a unique role in nutrient homeostasis. Its anatomical location makes it ideally suited to control the systemic supply of absorbed nutrients, and it is the primary organ that can both consume and produce substantial amounts of glucose. Moreover, it is the site of a substantial fraction (about 25 %) of the body's protein synthesis, and the liver and other organs of the splanchnic bed play an important role in sparing dietary N by storing ingested amino acids. This hepatic anabolism is under the control of hormonal and nutritional changes that occur during food intake. In particular, the route of nutrient delivery, i.e. oral (or intraportal) v. peripheral venous, appears to impact upon the disposition of the macronutrients and also to affect both hepatic and whole-body nutrient metabolism. Intraportal glucose delivery significantly enhances net hepatic glucose uptake, compared with glucose infusion via a peripheral vein. On the other hand, concomitant intraportal infusion of both glucose and gluconeogenic amino acids significantly decreases net hepatic glucose uptake, compared with infusion of the same mass of glucose by itself. Delivery of amino acids via the portal vein may enhance their hepatic uptake, however. Elevation of circulating lipids under postprandial conditions appears to impair both hepatic and whole-body glucose disposal. Thus, the liver's role in nutrient disposal and metabolism is highly responsive to the route of nutrient delivery, and this is an important consideration in planning nutrition support and optimising anabolism in vulnerable patients.
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Vujovic M, Nordström K, Gauthier K, Flamant F, Visser TJ, Vennström B, Mittag J. Interference of a mutant thyroid hormone receptor alpha1 with hepatic glucose metabolism. Endocrinology 2009; 150:2940-7. [PMID: 19282388 DOI: 10.1210/en.2008-1085] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mice expressing the mutant thyroid hormone receptor TRalpha1R384C, which has a 10-fold reduced affinity to the ligand T(3), exhibit hypermetabolism due to an overactivation of the sympathetic nervous system. To define the consequences in the liver, we analyzed hepatic metabolism and the regulation of liver genes in the mutant mice. Our results showed that hepatic phosphoenolpyruvate-carboxykinase was up-regulated and pyruvate kinase mRNA down-regulated, contrary to what observed after T(3) treatment. In contrast, mice expressing a mutant TRalpha1L400R specifically in the liver did not show a dysregulation of these genes; however, when the TRalpha1L400R was expressed ubiquitously, the hepatic phenotype differed from TRalpha1R384C animals, suggesting that the localization of the mutation plays an important role for its consequences on glucose metabolism. Furthermore, we observed that glycogen stores were completely depleted in TRalpha1R384C animals, despite increased gluconeogenesis and decreased glycolysis. Exposure of the mutant mice to high maternal levels of thyroid hormone during fetal development leads to a normal liver phenotype in the adult. Our results show how genetic and maternal factors interact to determine the metabolic setpoint of the offspring and indicate an important role for maternal thyroid hormone in the susceptibility to metabolic disorders in adulthood.
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Affiliation(s)
- Milica Vujovic
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
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