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McKay DM, Defaye M, Rajeev S, MacNaughton WK, Nasser Y, Sharkey KA. Neuroimmunophysiology of the gastrointestinal tract. Am J Physiol Gastrointest Liver Physiol 2024; 326:G712-G725. [PMID: 38626403 DOI: 10.1152/ajpgi.00075.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 04/18/2024]
Abstract
Gut physiology is the epicenter of a web of internal communication systems (i.e., neural, immune, hormonal) mediated by cell-cell contacts, soluble factors, and external influences, such as the microbiome, diet, and the physical environment. Together these provide the signals that shape enteric homeostasis and, when they go awry, lead to disease. Faced with the seemingly paradoxical tasks of nutrient uptake (digestion) and retarding pathogen invasion (host defense), the gut integrates interactions between a variety of cells and signaling molecules to keep the host nourished and protected from pathogens. When the system fails, the outcome can be acute or chronic disease, often labeled as "idiopathic" in nature (e.g., irritable bowel syndrome, inflammatory bowel disease). Here we underscore the importance of a holistic approach to gut physiology, placing an emphasis on intercellular connectedness, using enteric neuroimmunophysiology as the paradigm. The goal of this opinion piece is to acknowledge the pace of change brought to our field via single-cell and -omic methodologies and other techniques such as cell lineage tracing, transgenic animal models, methods for culturing patient tissue, and advanced imaging. We identify gaps in the field and hope to inspire and challenge colleagues to take up the mantle and advance awareness of the subtleties, intricacies, and nuances of intestinal physiology in health and disease by defining communication pathways between gut resident cells, those recruited from the circulation, and "external" influences such as the central nervous system and the gut microbiota.
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Affiliation(s)
- Derek M McKay
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
- Gastrointestinal Research Group, University of Calgary, Calgary, Alberta, Canada
- Inflammation Research Network, University of Calgary, Calgary, Alberta, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Manon Defaye
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
- Gastrointestinal Research Group, University of Calgary, Calgary, Alberta, Canada
- Inflammation Research Network, University of Calgary, Calgary, Alberta, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sruthi Rajeev
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
- Gastrointestinal Research Group, University of Calgary, Calgary, Alberta, Canada
- Inflammation Research Network, University of Calgary, Calgary, Alberta, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Wallace K MacNaughton
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
- Gastrointestinal Research Group, University of Calgary, Calgary, Alberta, Canada
- Inflammation Research Network, University of Calgary, Calgary, Alberta, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Yasmin Nasser
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
- Gastrointestinal Research Group, University of Calgary, Calgary, Alberta, Canada
- Inflammation Research Network, University of Calgary, Calgary, Alberta, Canada
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Keith A Sharkey
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
- Gastrointestinal Research Group, University of Calgary, Calgary, Alberta, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
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2
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Idrizaj E, Nistri S, Nardini P, Baccari MC. Adiponectin affects ileal contractility of mouse preparations. Am J Physiol Gastrointest Liver Physiol 2024; 326:G187-G194. [PMID: 38111974 DOI: 10.1152/ajpgi.00203.2023] [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: 09/19/2023] [Revised: 12/01/2023] [Accepted: 12/07/2023] [Indexed: 12/20/2023]
Abstract
Adiponectin (ADPN) has been reported to induce inhibitory effects on gastric motor activity, which, being a source of peripheral satiety signals, would contribute to the central anorexigenic effects of the hormone in rodents. However, peripheral satiety signals can also originate from the small intestine. Since there are no data on the effects of ADPN in this gut region, the present study aimed to investigate whether ADPN affects murine ileal contractility. Immunofluorescence experiments and Western blot were also performed to reveal the expression of ADPN receptors. Mechanical responses of ileal preparations were recorded in vitro via force-displacement transducers. Preparations showed a tetrodotoxin- and atropine-insensitive spontaneous contractile activity. Electrical field stimulation (EFS) induced tetrodotoxin- and atropine-sensitive contractile responses. ADPN induced a decay of the basal tension and decreased the amplitude of either the spontaneous contractility or the EFS-induced excitatory responses. All ADPN effects were abolished by the nitric oxide (NO) synthesis inhibitor NG-nitro l-arginine. The expression of the ADPN receptor, AdipoR1, but not AdipoR2, was also revealed in enteric glial cells. The present results offer the first evidence that ADPN acts on ileal preparations. The hormone exerts inhibitory effects, likely involving AdipoR1 on enteric glial cells and NO. From a physiological point of view, it could be hypothesized that the depressant action of ADPN on ileal contractility represents an additional peripheral satiety signal which, as also described for the ileal brake, could contribute to the central anorexigenic effects of the hormone.NEW & NOTEWORTHY This study provides the first evidence that adiponectin (ADPN) is able to act on ileal preparations. Functional results demonstrate that the hormone, other than causing a slight decay of the basal tension, depresses the amplitude of both spontaneous contractility and neurally induced excitatory responses of the mouse ileum through the involvement of nitric oxide. The expression of the ADPN receptor AdipoR1 and its localization on glial cells was revealed by Western blot and immunofluorescence analysis.
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Affiliation(s)
- Eglantina Idrizaj
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Firenze, Italy
| | - Silvia Nistri
- Department of Experimental and Clinical Medicine, Imaging Platform, University of Florence, Firenze, Italy
| | - Patrizia Nardini
- Department of Experimental and Clinical Medicine, Imaging Platform, University of Florence, Firenze, Italy
| | - Maria Caterina Baccari
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, Firenze, Italy
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Thomasi B, Gulbransen B. Mini-review: Intercellular communication between enteric glia and neurons. Neurosci Lett 2023; 806:137263. [PMID: 37085112 PMCID: PMC10150911 DOI: 10.1016/j.neulet.2023.137263] [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: 02/23/2023] [Revised: 04/13/2023] [Accepted: 04/17/2023] [Indexed: 04/23/2023]
Abstract
The enteric nervous system is a dense network of enteric neurons and glia housed in the gastrointestinal tract. This system is responsible for performing several functions that enable digestion as well as maintaining gut homeostasis through diverse signaling processes including those that arise from interactions with the immune system. Bidirectional communication between enteric neurons and enteric glia has gained increased attention for playing essential roles in enteric nervous system function. Neuronal mediators such as neurotransmitters stimulate enteric glia and subsequent gliotransmission processes refine neuronal signaling during intestinal motor control. In this mini-review, we present and discuss the basis of intercellular signaling between neurons and glia in the enteric nervous system and the relevance of these interactions to gut function.
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Prochera A, Rao M. Mini-Review: Enteric glial regulation of the gastrointestinal epithelium. Neurosci Lett 2023; 805:137215. [PMID: 37001854 PMCID: PMC10125724 DOI: 10.1016/j.neulet.2023.137215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/11/2023] [Accepted: 03/27/2023] [Indexed: 03/31/2023]
Abstract
Many enteric glia are located along nerve fibers in the gut mucosa where they form close associations with the epithelium lining the gastrointestinal tract. The gut epithelium is essential for absorbing nutrients, regulating fluid flux, forming a physical barrier to prevent the entry of pathogens and toxins into the host, and participating in immune responses. Disruptions to this epithelium are linked to numerous diseases, highlighting its central importance in maintaining health. Accumulating evidence indicates that glia regulate gut epithelial homeostasis. Observations from glial-epithelial co-cultures in vitro and mouse genetic models in vivo suggest that enteric glia influence several important features of the gut epithelium including barrier integrity, ion transport, and capacity for self-renewal. Here we review the evidence for enteric glial regulation of the intestinal epithelium, with a focus on these three features of its biology.
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Affiliation(s)
- Aleksandra Prochera
- Department of Pediatrics, Boston Children's Hospital and Harvard Medical School, 300 Longwood Ave, Boston, MA 02115, USA; Program in Immunology, Harvard Medical School, Boston, MA, USA
| | - Meenakshi Rao
- Department of Pediatrics, Boston Children's Hospital and Harvard Medical School, 300 Longwood Ave, Boston, MA 02115, USA.
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5
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ZHAO X, MU J, YI R. Research progress of naturally fermented yogurt with lactic acid bacteria in Xinjiang: a review of anti-constipation probiotics. FOOD SCIENCE AND TECHNOLOGY 2022. [DOI: 10.1590/fst.23722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Xin ZHAO
- Chongqing University of Education, China
| | - Jianfei MU
- Chongqing University of Education, China
| | - Ruokun YI
- Chongqing University of Education, China
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Meira de-Faria F, Casado-Bedmar M, Mårten Lindqvist C, Jones MP, Walter SA, Keita ÅV. Altered interaction between enteric glial cells and mast cells in the colon of women with irritable bowel syndrome. Neurogastroenterol Motil 2021; 33:e14130. [PMID: 33797165 DOI: 10.1111/nmo.14130] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 02/22/2021] [Accepted: 03/09/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND Enteric glial cells (EGC) and mast cells (MC) are intimately associated with gastrointestinal physiological functions. We aimed to investigate EGC-MC interaction in irritable bowel syndrome (IBS), a gut-brain disorder linked to increased intestinal permeability, and MC. METHODS Parallel approaches were used to quantify EGC markers in colonic biopsies from healthy controls (HC) and patients with IBS. Data were correlated with MC, vasoactive intestinal polypeptide (VIP) and VIP receptors (VPAC1/VPAC2) expressions, and bacterial translocation through biopsies mounted in Ussing chambers. In addition, we investigated the effects of EGC mediators on colonic permeability and the pharmacological-induced responses of EGC and MC cell lines. KEY RESULTS Immunofluorescence of IBS colonic mucosa, as well as Western blotting and ELISA of IBS biopsy lysates, revealed increased glial fibrillary intermediate filament (GFAP) expression, indicating EGC activation. Mucosal GFAP correlated with increased MC and VPAC1+ MC numbers and decreased VIP+ MC, which seemed to control bacterial translocation in HC. In the contrary, EGC activation in IBS correlated with less MC and VPAC1+ MC numbers, and more VIP+ MC. In vitro, MC and EGC cell lines showed intracellular calcium responses to each other's mediators. Furthermore, EGC mediators prevented VIP-induced MC degranulation, while MC mediators induced a reactive EGC phenotype. In Ussing chambers, EGC mediators decreased paracellular passage through healthy colonic biopsies. CONCLUSIONS & INFERENCES Findings suggest the involvement of EGC and MC in the control of barrier function in the human colon and indicate a potential EGC-MC interaction that seems altered in IBS, with detrimental consequences to colonic permeability. Altogether, results suggest that imbalanced EGC-MC communication contributes to the pathophysiology of IBS.
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Affiliation(s)
- Felipe Meira de-Faria
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Maite Casado-Bedmar
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Carl Mårten Lindqvist
- Department of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | | | - Susanna A Walter
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.,Department of Gastroenterology, Linköping University, Linköping, Sweden
| | - Åsa V Keita
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
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Seguella L, Gulbransen BD. Enteric glial biology, intercellular signalling and roles in gastrointestinal disease. Nat Rev Gastroenterol Hepatol 2021; 18:571-587. [PMID: 33731961 PMCID: PMC8324524 DOI: 10.1038/s41575-021-00423-7] [Citation(s) in RCA: 110] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/28/2021] [Indexed: 02/07/2023]
Abstract
One of the most transformative developments in neurogastroenterology is the realization that many functions normally attributed to enteric neurons involve interactions with enteric glial cells: a large population of peripheral neuroglia associated with enteric neurons throughout the gastrointestinal tract. The notion that glial cells function solely as passive support cells has been refuted by compelling evidence that demonstrates that enteric glia are important homeostatic cells of the intestine. Active signalling mechanisms between enteric glia and neurons modulate gastrointestinal reflexes and, in certain circumstances, function to drive neuroinflammatory processes that lead to long-term dysfunction. Bidirectional communication between enteric glia and immune cells contributes to gastrointestinal immune homeostasis, and crosstalk between enteric glia and cancer stem cells regulates tumorigenesis. These neuromodulatory and immunomodulatory roles place enteric glia in a unique position to regulate diverse gastrointestinal disease processes. In this Review, we discuss current concepts regarding enteric glial development, heterogeneity and functional roles in gastrointestinal pathophysiology and pathophysiology, with a focus on interactions with neurons and immune cells. We also present a working model to differentiate glial states based on normal function and disease-induced dysfunctions.
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Affiliation(s)
- Luisa Seguella
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, Rome, Italy
- Department of Physiology, Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - Brian D Gulbransen
- Department of Physiology, Neuroscience Program, Michigan State University, East Lansing, MI, USA.
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Duan H, Cai X, Luan Y, Yang S, Yang J, Dong H, Zeng H, Shao L. Regulation of the Autonomic Nervous System on Intestine. Front Physiol 2021; 12:700129. [PMID: 34335306 PMCID: PMC8317205 DOI: 10.3389/fphys.2021.700129] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 06/22/2021] [Indexed: 12/12/2022] Open
Abstract
Intestine is composed of various types of cells including absorptive epithelial cells, goblet cells, endocrine cells, Paneth cells, immunological cells, and so on, which play digestion, absorption, neuroendocrine, immunological function. Intestine is innervated with extrinsic autonomic nerves and intrinsic enteric nerves. The neurotransmitters and counterpart receptors are widely distributed in the different intestinal cells. Intestinal autonomic nerve system includes sympathetic and parasympathetic nervous systems, which regulate cellular proliferation and function in intestine under physiological and pathophysiological conditions. Presently, distribution and functional characteristics of autonomic nervous system in intestine were reviewed. How autonomic nervous system regulates intestinal cell proliferation was discussed. Function of autonomic nervous system on intestinal diseases was extensively reviewed. It might be helpful to properly manipulate autonomic nervous system during treating different intestinal diseases.
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Affiliation(s)
- Hongyi Duan
- Medical College of Nanchang University, Nanchang, China
| | - Xueqin Cai
- Medical College of Nanchang University, Nanchang, China
| | - Yingying Luan
- Medical College of Nanchang University, Nanchang, China
| | - Shuo Yang
- Medical College of Nanchang University, Nanchang, China.,Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang, China
| | - Juan Yang
- Medical College of Nanchang University, Nanchang, China.,Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang, China
| | - Hui Dong
- Medical College of Nanchang University, Nanchang, China.,Jiangxi Provincial Key Laboratory of Interdisciplinary Science, Nanchang University, Nanchang, China
| | - Huihong Zeng
- Medical College of Nanchang University, Nanchang, China.,Jiangxi Provincial Key Laboratory of Interdisciplinary Science, Nanchang University, Nanchang, China
| | - Lijian Shao
- Medical College of Nanchang University, Nanchang, China.,Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang, China.,Jiangxi Provincial Key Laboratory of Interdisciplinary Science, Nanchang University, Nanchang, China
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9
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Broadhead MJ, Miles GB. A common role for astrocytes in rhythmic behaviours? Prog Neurobiol 2021; 202:102052. [PMID: 33894330 DOI: 10.1016/j.pneurobio.2021.102052] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 03/03/2021] [Accepted: 04/13/2021] [Indexed: 01/16/2023]
Abstract
Astrocytes are a functionally diverse form of glial cell involved in various aspects of nervous system infrastructure, from the metabolic and structural support of neurons to direct neuromodulation of synaptic activity. Investigating how astrocytes behave in functionally related circuits may help us understand whether there is any conserved logic to the role of astrocytes within neuronal networks. Astrocytes are implicated as key neuromodulatory cells within neural circuits that control a number of rhythmic behaviours such as breathing, locomotion and circadian sleep-wake cycles. In this review, we examine the evidence that astrocytes are directly involved in the regulation of the neural circuits underlying six different rhythmic behaviours: locomotion, breathing, chewing, gastrointestinal motility, circadian sleep-wake cycles and oscillatory feeding behaviour. We discuss how astrocytes are integrated into the neuronal networks that regulate these behaviours, and identify the potential gliotransmission signalling mechanisms involved. From reviewing the evidence of astrocytic involvement in a range of rhythmic behaviours, we reveal a heterogenous array of gliotransmission mechanisms, which help to regulate neuronal networks. However, we also observe an intriguing thread of commonality, in the form of purinergic gliotransmission, which is frequently utilised to facilitate feedback inhibition within rhythmic networks to constrain a given behaviour within its operational range.
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Affiliation(s)
- Matthew J Broadhead
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK.
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
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10
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Nicotinic Acetylcholine Receptor Involvement in Inflammatory Bowel Disease and Interactions with Gut Microbiota. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18031189. [PMID: 33572734 PMCID: PMC7908252 DOI: 10.3390/ijerph18031189] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022]
Abstract
The gut-brain axis describes a complex interplay between the central nervous system and organs of the gastrointestinal tract. Sensory neurons of dorsal root and nodose ganglia, neurons of the autonomic nervous system, and immune cells collect and relay information about the status of the gut to the brain. A critical component in this bi-directional communication system is the vagus nerve which is essential for coordinating the immune system’s response to the activities of commensal bacteria in the gut and to pathogenic strains and their toxins. Local control of gut function is provided by networks of neurons in the enteric nervous system also called the ‘gut-brain’. One element common to all of these gut-brain systems is the expression of nicotinic acetylcholine receptors. These ligand-gated ion channels serve myriad roles in the gut-brain axis including mediating fast synaptic transmission between autonomic pre- and postganglionic neurons, modulation of neurotransmitter release from peripheral sensory and enteric neurons, and modulation of cytokine release from immune cells. Here we review the role of nicotinic receptors in the gut-brain axis with a focus on the interplay of these receptors with the gut microbiome and their involvement in dysregulation of gut function and inflammatory bowel diseases.
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11
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Enteric Glia at the Crossroads between Intestinal Immune System and Epithelial Barrier: Implications for Parkinson Disease. Int J Mol Sci 2020; 21:ijms21239199. [PMID: 33276665 PMCID: PMC7730281 DOI: 10.3390/ijms21239199] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/30/2020] [Accepted: 11/30/2020] [Indexed: 12/15/2022] Open
Abstract
Over recent years, several investigations have suggested that Parkinson’s disease (PD) can be regarded as the consequence of a bowel disorder. Indeed, gastrointestinal symptoms can occur at all stages of this neurodegenerative disease and in up to a third of cases, their onset can precede the involvement of the central nervous system. Recent data suggest that enteric glial cells (EGCs) may play a major role in PD-related gastrointestinal disturbances, as well as in the development and progression of the central disease. In addition to their trophic and structural functions, EGCs are crucial for the homeostatic control of a wide range of gastrointestinal activities. The main purpose of this review was to provide a detailed overview of the role of EGCs in intestinal PD-associated alterations, with particular regard for their participation in digestive and central inflammation as well as the dynamic interactions between glial cells and intestinal epithelial barrier. Accumulating evidence suggests that several pathological intestinal conditions, associated with an impairment of barrier permeability, may trigger dysfunctions of EGCs and their shift towards a proinflammatory phenotype. The reactive gliosis is likely responsible for PD-related neuroinflammation and the associated pathological changes in the ENS. Thus, ameliorating the efficiency of mucosal barrier, as well as avoiding IEB disruption and the related reactive gliosis, might theoretically prevent the onset of PD or, at least, counteract its progression.
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12
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Broadhead MJ, Miles GB. Bi-Directional Communication Between Neurons and Astrocytes Modulates Spinal Motor Circuits. Front Cell Neurosci 2020; 14:30. [PMID: 32180706 PMCID: PMC7057799 DOI: 10.3389/fncel.2020.00030] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 02/03/2020] [Indexed: 01/22/2023] Open
Abstract
Evidence suggests that astrocytes are not merely supportive cells in the nervous system but may actively participate in the control of neural circuits underlying cognition and behavior. In this study, we examined the role of astrocytes within the motor circuitry of the mammalian spinal cord. Pharmacogenetic manipulation of astrocytic activity in isolated spinal cord preparations obtained from neonatal mice revealed astrocyte-derived, adenosinergic modulation of the frequency of rhythmic output generated by the locomotor central pattern generator (CPG) network. Live Ca2+ imaging demonstrated increased activity in astrocytes during locomotor-related output and in response to the direct stimulation of spinal neurons. Finally, astrocytes were found to respond to neuronally-derived glutamate in a metabotropic glutamate receptor 5 (mGluR5) dependent manner, which in turn drives astrocytic modulation of the locomotor network. Our work identifies bi-directional signaling mechanisms between neurons and astrocytes underlying modulatory feedback control of motor circuits, which may act to constrain network output within optimal ranges for movement.
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Affiliation(s)
- Matthew J Broadhead
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom
| | - Gareth B Miles
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom
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13
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Knauf C, Abot A, Wemelle E, Cani PD. Targeting the Enteric Nervous System to Treat Metabolic Disorders? "Enterosynes" as Therapeutic Gut Factors. Neuroendocrinology 2020; 110:139-146. [PMID: 31280267 DOI: 10.1159/000500602] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 04/28/2019] [Indexed: 11/19/2022]
Abstract
The gut-brain axis is of crucial importance for controlling glucose homeostasis. Alteration of this axis promotes the type 2 diabetes (T2D) phenotype (hyperglycaemia, insulin resistance). Recently, a new concept has emerged to demonstrate the crucial role of the enteric nervous system in the control of glycaemia via the hypothalamus. In diabetic patients and mice, modification of enteric neurons activity in the proximal part of the intestine generates a duodenal hyper-contractility that generates an aberrant message from the gut to the brain. In turn, the hypothalamus sends an aberrant efferent message that provokes a state of insulin resistance, which is characteristic of a T2D state. Targeting the enteric nervous system of the duodenum is now recognized as an innovative strategy for treatment of diabetes. By acting in the intestine, bioactive gut molecules that we called "enterosynes" can modulate the function of a specific type of neurons of the enteric nervous system to decrease the contraction of intestinal smooth muscle cells. Here, we focus on the origins of enterosynes (hormones, neurotransmitters, nutrients, microbiota, and immune factors), which could be considered therapeutic factors, and we describe their modes of action on enteric neurons. This unsuspected action of enterosynes is proposed for the treatment of T2D, but it could be applied for other therapeutic solutions that implicate communication between the gut and brain.
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Affiliation(s)
- Claude Knauf
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1220, Université Paul Sabatier, UPS, Institut de Recherche en Santé Digestive et Nutrition (IRSD), Toulouse, France,
- NeuroMicrobiota, European Associated Laboratory (EAL) INSERM, Toulouse, France,
| | - Anne Abot
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1220, Université Paul Sabatier, UPS, Institut de Recherche en Santé Digestive et Nutrition (IRSD), Toulouse, France
- NeuroMicrobiota, European Associated Laboratory (EAL) INSERM, Toulouse, France
| | - Eve Wemelle
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1220, Université Paul Sabatier, UPS, Institut de Recherche en Santé Digestive et Nutrition (IRSD), Toulouse, France
- NeuroMicrobiota, European Associated Laboratory (EAL) INSERM, Toulouse, France
| | - Patrice D Cani
- NeuroMicrobiota, European Associated Laboratory (EAL) INSERM, Toulouse, France
- UCLouvain, Université Catholique de Louvain, WELBIO - Walloon Excellence in Life Sciences and BIOtechnology, Louvain Drug Research Institute, Metabolism and Nutrition Research Group, Brussels, Belgium
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14
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Yeh KM, Johansson O, Le H, Rao K, Markus I, Perera DS, Lubowski DZ, King DW, Zhang L, Chen H, Liu L. Cystic fibrosis transmembrane conductance regulator modulates enteric cholinergic activities and is abnormally expressed in the enteric ganglia of patients with slow transit constipation. J Gastroenterol 2019; 54:994-1006. [PMID: 31392489 DOI: 10.1007/s00535-019-01610-9] [Citation(s) in RCA: 13] [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] [Received: 05/16/2019] [Accepted: 07/31/2019] [Indexed: 02/04/2023]
Abstract
BACKGROUND Cystic fibrosis transmembrane conductance regulator (CFTR) was recently found in the enteric nervous system, where its role is unclear. We aimed to identify which enteric neuronal structures express CFTR, whether CFTR modulates enteric neurotransmission and if altered CFTR expression is associated with slow transit constipation (STC). METHODS Immunofluorescence double labeling was performed to localize CFTR with various neuronal and glial cell markers in the human colon. The immunoreactivity (IR) of CFTR and choline acetyltransferase (ChAT) on myenteric plexus of control and STC colon was quantitatively analyzed. In control colonic muscle strips, electrical field stimulation (EFS) evoked contractile responses and the release of acetylcholine (ACh) was measured in the presence of the CFTR channel inhibitor, CFTR(inh)-172. RESULTS CFTR-IR was densely localized to myenteric ganglia, where it was co-localized with neuronal markers HuC/D and β-tubulin, and glial marker S-100 but little with glial fibrillary acidic protein. Vesicular ACh transport was almost exclusively co-localized with CFTR, but neurons expressing nitric oxide synthase were CFTR negative. Significant reductions of CFTR-IR (P < 0.01) and ChAT-IR (P < 0.05) were observed on myenteric ganglia of STC compared to control. Pre-treatment of colonic muscle strips with CFTR(inh)-172 (10 µM) significantly inhibited EFS-evoked contractile responses (P < 0.01) and ACh release (P < 0.05). CONCLUSIONS Co-localization of CFTR-IR with cholinergic markers, inhibition of EFS-induced colonic muscle contractility and ACh release by CFTR(inh)-172 suggest that CFTR modulates enteric cholinergic neurotransmission. The downregulation of CFTR and ChAT in myenteric ganglia of STC correlated with the impaired contractile responses to EFS.
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Affiliation(s)
- Ka Ming Yeh
- Department of Pharmacology, Faculty of Medicine, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Olle Johansson
- Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
| | - Huy Le
- Department of Pharmacology, Faculty of Medicine, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Karan Rao
- Department of Pharmacology, Faculty of Medicine, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Irit Markus
- Department of Pharmacology, Faculty of Medicine, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | | | | | | | - Li Zhang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Hongzhuan Chen
- School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Lu Liu
- Department of Pharmacology, Faculty of Medicine, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
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15
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Mohajeri MH, La Fata G, Steinert RE, Weber P. Relationship between the gut microbiome and brain function. Nutr Rev 2019; 76:481-496. [PMID: 29701810 DOI: 10.1093/nutrit/nuy009] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It has become increasingly evident in recent years that the gut microbiome and the brain communicate in a bidirectional manner, with each possibly affecting the other's functions. Substantial research has aimed to understand the mechanisms of this interaction and to outline strategies for preventing or treating nervous system-related disturbances. This review explores the evidence demonstrating how the gut microbiome may affect brain function in adults, thereby having an impact on stress, anxiety, depression, and cognition. In vitro, in vivo, and human studies reporting an association between a change in the gut microbiome and functional changes in the brain are highlighted, as are studies outlining the mechanisms by which the brain affects the microbiome and the gastrointestinal tract. Possible modes of action to explain how the gut microbiome and the brain functionally affect each other are proposed. Supplemental probiotics to combat brain-related dysfunction offer a promising approach, provided future research elucidates their mode of action and possible side effects. Further studies are warranted to establish how pre- and probiotic interventions may help to balance brain function in healthy and diseased individuals.
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Affiliation(s)
- M Hasan Mohajeri
- Department of Human Nutrition, DSM Nutritional Products, Basel, Switzerland
| | - Giorgio La Fata
- Department of Human Nutrition, DSM Nutritional Products, Basel, Switzerland
| | - Robert E Steinert
- Department of Human Nutrition, DSM Nutritional Products, Basel, Switzerland
| | - Peter Weber
- Department of Human Nutrition, DSM Nutritional Products, Basel, Switzerland
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16
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Boesmans W, Hao MM, Fung C, Li Z, Van den Haute C, Tack J, Pachnis V, Vanden Berghe P. Structurally defined signaling in neuro-glia units in the enteric nervous system. Glia 2019; 67:1167-1178. [PMID: 30730592 PMCID: PMC6593736 DOI: 10.1002/glia.23596] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 01/11/2019] [Accepted: 01/11/2019] [Indexed: 12/21/2022]
Abstract
Coordination of gastrointestinal function relies on joint efforts of enteric neurons and glia, whose crosstalk is vital for the integration of their activity. To investigate the signaling mechanisms and to delineate the spatial aspects of enteric neuron-to-glia communication within enteric ganglia we developed a method to stimulate single enteric neurons while monitoring the activity of neighboring enteric glial cells. We combined cytosolic calcium uncaging of individual enteric neurons with calcium imaging of enteric glial cells expressing a genetically encoded calcium indicator and demonstrate that enteric neurons signal to enteric glial cells through pannexins using paracrine purinergic pathways. Sparse labeling of enteric neurons and high-resolution analysis of the structural relation between neuronal cell bodies, varicose release sites and enteric glia uncovered that this form of neuron-to-glia communication is contained between the cell body of an enteric neuron and its surrounding enteric glial cells. Our results reveal the spatial and functional foundation of neuro-glia units as an operational cellular assembly in the enteric nervous system.
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Affiliation(s)
- Werend Boesmans
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium.,Department of Pathology, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands.,Biomedical Research Institute (BIOMED), Hasselt University, Hasselt, Belgium
| | - Marlene M Hao
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium.,Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Australia
| | - Candice Fung
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Zhiling Li
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Chris Van den Haute
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, University of Leuven, Leuven, Belgium.,Leuven Viral Vector Core, University of Leuven, Leuven, Belgium
| | - Jan Tack
- Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
| | - Vassilis Pachnis
- Development and Homeostasis of the Nervous System Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Leuven, Belgium
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17
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Fornai M, van den Wijngaard RM, Antonioli L, Pellegrini C, Blandizzi C, de Jonge WJ. Neuronal regulation of intestinal immune functions in health and disease. Neurogastroenterol Motil 2018; 30:e13406. [PMID: 30058092 DOI: 10.1111/nmo.13406] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/11/2018] [Indexed: 12/26/2022]
Abstract
BACKGROUND Nerve-mucosa interactions control various elements of gastrointestinal functions, including mucosal host defense, gut barrier function, and epithelial cell growth and differentiation. In both intestinal and extra-intestinal diseases, alterations of autonomic nerve activity have been observed to be concurrent with the disease course, such as in inflammatory and functional bowel diseases, and neurodegenerative diseases. This is relevant as the extrinsic autonomic nervous system is increasingly recognized to modulate gut inflammatory responses. The molecular and cellular mechanisms through which the extrinsic and intrinsic nerve pathways may regulate digestive mucosal functions have been investigated in several pre-clinical and clinical studies. PURPOSE The present review focuses on the involvement of neural pathways in gastrointestinal disease, and addresses the current strategies to intervene with neuronal pathway as a means of treatment.
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Affiliation(s)
- M Fornai
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.,Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands
| | - R M van den Wijngaard
- Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands
| | - L Antonioli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - C Pellegrini
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - C Blandizzi
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - W J de Jonge
- Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands
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18
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Choudhury MG, Kumari S, Das KB, Saha N. Lipopolysaccharide causes NFĸB-mediated induction of inducible nitric oxide synthase gene and more production of nitric oxide in air-breathing catfish, Clarias magur (Hamilton). Gene 2018. [DOI: 10.1016/j.gene.2018.03.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Increased population of immature enteric glial cells in the resected proximal ganglionic bowel of Hirschsprung's disease patients. J Surg Res 2017; 218:150-155. [PMID: 28985842 DOI: 10.1016/j.jss.2017.05.062] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/09/2017] [Accepted: 05/18/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Enteric glial cells are essential for normal gastrointestinal function. Abnormalities in glial structure, development, or function lead to disturbances in gastrointestinal physiology. Fatty acid-binding protein 7 (FABP7) is a marker of immature enteric glial cells, whereas S100 is expressed only by mature glial cells. Patients with Hirschsprung's disease (HSCR) often suffer from dysmotility and enterocolitis despite proper surgery. We designed this study to determine the distribution and expression of glial cells in patients with HSCR compared to normal controls. METHODS We investigated FABP7, S100, and PGP 9.5 expressions in both the ganglionic and aganglionic bowel of patients with HSCR (n = 6) versus normal control colon (n = 6). Protein distribution was assessed by using immunofluorescence and confocal microscopy. Gene and protein expressions were quantified using quantitative real-time polymerase chain reaction (qPCR), Western blot analysis, and densitometry. RESULTS qPCR and Western blot analysis demonstrated a significantly increased FABP7 expression in ganglionic specimens compared to control specimen (P < 0.05). Confocal microscopy revealed FABP7+ glia cells lie under the colonic epithelium and in close apposition to enteric neurons in the ganglionic bowel. CONCLUSIONS The significantly increased number of immature enteric glial cells (EGCs) in the ganglionic bowel of HSCR patients may have adverse effect on the function of enteric neurons and intestinal barrier and thus predispose these patients to intestinal motility problems and enterocolitis.
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20
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Grubišić V, Gulbransen BD. Enteric glial activity regulates secretomotor function in the mouse colon but does not acutely affect gut permeability. J Physiol 2017; 595:3409-3424. [PMID: 28066889 DOI: 10.1113/jp273492] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 11/30/2016] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS The role of enteric glial cell activity in the acute regulation of epithelial barrier and secretomotor functions of the intestines under physiological conditions is not clear. We used transgenic mice to modify glial activity and found that enteric glia significantly contribute to the neurogenic ion transport while glial activity does not appear to play a major role in the acute regulation of barrier function. The selective activation of glial activity evoked electrogenic ion transport primarily through neural pathways and was sufficient to drive electrogenic ion transport to an extent equal to the direct activation of neurogenic ion transport. These findings provide novel insight into the cellular mechanisms that control fluid transport homeostasis in the intestine and might provide novel therapeutic avenues for functional diarrheal diseases. ABSTRACT Enteric glial cells are often implicated in the regulation of epithelial barrier and secretomotor functions of the intestines. But whether glial cell activity regulates these functions acutely under physiological conditions is not clear. We addressed this issue by using transgenic animal models to modify the activity of enteric glia, either reducing glial expression of connexin 43 in Sox10::CreERT2+/- /Cx43f/f mice or activating glial calcium responses in GFAP::hM3Dq mice, and tested the effects on colonic barrier function and electrogenic ion transport in Ussing chambers. We assessed neuronal-dependent and -independent contributions by activating or inhibiting neurogenic activity with veratridine and tetrodotoxin, respectively. Our results show that the reduction of glial Cx43 expression in Sox10::CreERT2+/- /Cx43f/f mice significantly reduced neurogenic ion transport. The selective glial activation in tissues from GFAP::hM3Dq mice evoked electrogenic ion transport to an extent equal to the direct activation of neurogenic ion transport with veratridine and glial driven responses consisted of both tetrodotoxin-sensitive and -insensitive components. The selective glial stimulation did not affect transmural ion conductance or cell-impermeant dye flux but the baseline ion conductance was more variable in Sox10::CreERT2+/- /Cx43f/f tissues. Together, our findings show that glial activity contributes to the regulation of electrogenic ion transport in the intestine through effects on neurons and possibly direct effects on epithelial cells. However, glial activity does not appear to play a major role in the acute regulation of barrier function. These findings provide novel insight into the cellular mechanisms that control fluid transport homeostasis in the intestine.
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Affiliation(s)
- Vladimir Grubišić
- Neuroscience Program, Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
| | - Brian D Gulbransen
- Neuroscience Program, Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
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21
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Liu GX, Gan HT. Effect of enteric nervous system on intestinal epithelial barrier in inflammatory bowel disease. Shijie Huaren Xiaohua Zazhi 2017; 25:107-113. [DOI: 10.11569/wcjd.v25.i2.107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Both enteric nervous system and intestinal epithelial barrier are vital components to ensure gut homeostasis. Recent studies have shown the implications of their close relationship for gut health and disease. By secreting neurotransmitters, the enteric nervous system plays an important role in regulating the epithelial barrier function. Meanwhile, communicating largely through the vagal nerve, the central nervous system could also interact with the intestinal epithelium through the enteric nervous system. Although the etiology and pathogenesis of inflammatory bowel disease remain elusive, increasing evidence has shown that the dysregulation of enteric nervous system affects both epithelial integrity and barrier function, which contributes to the occurrence and development of inflammatory bowel disease. This review will summarize the current knowledge regarding the effect of enteric nervous system on intestinal epithelial barrier and its implication in the development of inflammatory bowel disease.
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22
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Grubišić V, Gulbransen BD. Enteric glia: the most alimentary of all glia. J Physiol 2017; 595:557-570. [PMID: 27106597 PMCID: PMC5233670 DOI: 10.1113/jp271021] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 01/06/2016] [Indexed: 12/12/2022] Open
Abstract
Glia (from Greek γλοία meaning 'glue') pertains to non-neuronal cells in the central (CNS) and peripheral nervous system (PNS) that nourish neurons and maintain homeostasis. In addition, glia are now increasingly appreciated as active regulators of numerous physiological processes initially considered exclusively under neuronal regulation. For instance, enteric glia, a collection of glial cells residing within the walls of the intestinal tract, regulate intestinal motility, a well-characterized reflex controlled by enteric neurons. Enteric glia also interact with various non-neuronal cell types in the gut wall such as enterocytes, enteroendocrine and immune cells and are therefore emerging as important local regulators of diverse gut functions. The intricate molecular mechanisms that govern glia-mediated regulation are beginning to be discovered, but much remains unknown about the functions of enteric glia in health and disease. Here we present a current view of the enteric glia and their regulatory roles in gastrointestinal (GI) (patho)physiology; from GI motility and epithelial barrier function to enteric neuroinflammation.
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Affiliation(s)
- Vladimir Grubišić
- Neuroscience Program, Department of PhysiologyMichigan State University567 Wilson RoadEast LansingMI48824USA
| | - Brian D. Gulbransen
- Neuroscience Program, Department of PhysiologyMichigan State University567 Wilson RoadEast LansingMI48824USA
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23
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Yamamoto M, Nishiyama M, Iizuka S, Suzuki S, Suzuki N, Aiso S, Nakahara J. Transient receptor potential vanilloid 1-immunoreactive signals in murine enteric glial cells. World J Gastroenterol 2016; 22:9752-9764. [PMID: 27956799 PMCID: PMC5124980 DOI: 10.3748/wjg.v22.i44.9752] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 09/19/2016] [Accepted: 10/10/2016] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the possible involvement of transient receptor potential vanilloid 1 (TRPV1) in maturation of enteric glial cells (EGCs).
METHODS Immunohistochemical and immunocytochemical techniques were used to analyze EGC markers in myenteric plexus (MP) as well as cultured MP cells and EGCs using TRPV1 knockout (KO) mice.
RESULTS We detected TRPV1-immunoreactive signals in EGC in the MP of wild-type (WT) but not KO mice. Expression of glial fibrillary acidic protein (GFAP) immunoreactive signals was lower at postnatal day (PD) 6 in KO mice, though the difference was not clear at PD 13 and PD 21. When MP cells were isolated and cultured from isolated longitudinal muscle-MP preparation from WT and KO mice, the yield of KO EGC was lower than that of WT EGC, while the yield of KO and WT smooth muscle cells showed no difference. Addition of BCTC, a TRPV1 antagonist, to enriched EGC culture resulted in a decrease in the protein ratio of GFAP to S100B, another EGC/astrocyte-specific marker.
CONCLUSION These results address the possibility that TRPV1 may be involved in the maturation of EGC, though further studies are necessary to validate this possibility.
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24
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Diss L, Dyball S, Ghela T, Golding J, Morris R, Robinson S, Tucker R, Walter T, Young P, Allen M, Fidalgo S, Gard P, Mabley J, Patel B, Chatterjee P, Yeoman M. Acute paraquat exposure impairs colonic motility by selectively attenuating nitrergic signalling in the mouse. Auton Neurosci 2016; 195:8-15. [PMID: 26853977 DOI: 10.1016/j.autneu.2016.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 01/25/2016] [Accepted: 01/27/2016] [Indexed: 01/06/2023]
Abstract
Paraquat, a common herbicide, is responsible for large numbers of deaths worldwide through both deliberate and accidental ingestion. Previous studies have eluded that the bioavailability of paraquat increases substantially with increasing dose and that these changes may in part be due to the effects that these high concentrations have on the gastrointestinal tract (GI tract). To date, the actions of acute, high concentrations (20mM for 60 min) of paraquat on the GI tract, particularly the colon which is a major site of paraquat absorption, are unknown. This study examined the effects of acute paraquat administration on colonic motility in the C57BL/6 mouse. Acute paraquat exposure decreased colonic motility and the amplitude of colonic migrating motor complexes (CMMCs), which are major motor patterns involved in faecal pellet propulsion. In isolated segments of distal colon, paraquat increased resting tension and markedly attenuated electrical field stimulation-evoked relaxations. Pharmacological dissection of paraquat's mechanism of action on both the CMMCs and field stimulated tissue using the nitric oxide synthase inhibitor NG-nitro-L-arginine and direct measurement of NO release from the myenteric plexus, demonstrated that paraquat selectively attenuates nitrergic signalling pathways. These changes did not appear to be due to alterations in colonic oxidative stress, inflammation or complex 1 activity, but were most likely caused by paraquat's ability to act as a redox couple. In summary, these data demonstrate that acute paraquat exposure attenuates colonic transit. These changes may facilitate the absorption of paraquat into the circulation and so facilitate its toxicity.
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Affiliation(s)
- Lucy Diss
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Sarah Dyball
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Tina Ghela
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Jonathan Golding
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Rachel Morris
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Stephen Robinson
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Rosemary Tucker
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Talia Walter
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Paul Young
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Marcus Allen
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Sara Fidalgo
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Paul Gard
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Jon Mabley
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Bhavik Patel
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Prabal Chatterjee
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK
| | - Mark Yeoman
- School of Pharmacy and Biomolecular Sciences, Huxley Building, College of Life, Health and Physical Sciences, University of Brighton, Brighton, East Sussex BN2 4GJ, UK.
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Hennig GW, Gould TW, Koh SD, Corrigan RD, Heredia DJ, Shonnard MC, Smith TK. Use of Genetically Encoded Calcium Indicators (GECIs) Combined with Advanced Motion Tracking Techniques to Examine the Behavior of Neurons and Glia in the Enteric Nervous System of the Intact Murine Colon. Front Cell Neurosci 2015; 9:436. [PMID: 26617487 PMCID: PMC4639702 DOI: 10.3389/fncel.2015.00436] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 10/16/2015] [Indexed: 12/19/2022] Open
Abstract
Genetically encoded Ca2+ indicators (GECIs) have been used extensively in many body systems to detect Ca2+ transients associated with neuronal activity. Their adoption in enteric neurobiology has been slower, although they offer many advantages in terms of selectivity, signal-to-noise and non-invasiveness. Our aims were to utilize a number of cell-specific promoters to express the Ca2+ indicator GCaMP3 in different classes of neurons and glia to determine their effectiveness in measuring activity in enteric neural networks during colonic motor behaviors. We bred several GCaMP3 mice: (1) Wnt1-GCaMP3, all enteric neurons and glia; (2) GFAP-GCaMP3, enteric glia; (3) nNOS-GaMP3, enteric nitrergic neurons; and (4) ChAT-GCaMP3, enteric cholinergic neurons. These mice allowed us to study the behavior of the enteric neurons in the intact colon maintained at a physiological temperature, especially during the colonic migrating motor complex (CMMC), using low power Ca2+ imaging. In this preliminary study, we observed neuronal and glial cell Ca2+ transients in specific cells in both the myenteric and submucous plexus in all of the transgenic mice variants. The number of cells that could be simultaneously imaged at low power (100–1000 active cells) through the undissected gut required advanced motion tracking and analysis routines. The pattern of Ca2+ transients in myenteric neurons showed significant differences in response to spontaneous, oral or anal stimulation. Brief anal elongation or mucosal stimulation, which evokes a CMMC, were the most effective stimuli and elicited a powerful synchronized and prolonged burst of Ca2+ transients in many myenteric neurons, especially when compared with the same neurons during a spontaneous CMMC. In contrast, oral elongation, which normally inhibits CMMCs, appeared to suppress Ca2+ transients in some of the neurons active during a spontaneous or an anally evoked CMMC. The activity in glial networks appeared to follow neural activity but continued long after neural activity had waned. With these new tools an unprecedented level of detail can be recorded from the enteric nervous system (ENS) with minimal manipulation of tissue. These techniques can be extended in order to better understand the roles of particular enteric neurons and glia during normal and disordered motility.
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Affiliation(s)
- Grant W Hennig
- Department of Physiology and Cell Biology, University of Nevada School of Medicine Reno, NV, USA
| | - Thomas W Gould
- Department of Physiology and Cell Biology, University of Nevada School of Medicine Reno, NV, USA
| | - Sang Don Koh
- Department of Physiology and Cell Biology, University of Nevada School of Medicine Reno, NV, USA
| | - Robert D Corrigan
- Department of Physiology and Cell Biology, University of Nevada School of Medicine Reno, NV, USA
| | - Dante J Heredia
- Department of Physiology and Cell Biology, University of Nevada School of Medicine Reno, NV, USA
| | - Matthew C Shonnard
- Department of Physiology and Cell Biology, University of Nevada School of Medicine Reno, NV, USA
| | - Terence K Smith
- Department of Physiology and Cell Biology, University of Nevada School of Medicine Reno, NV, USA
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26
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Fichna J, Poole DP, Veldhuis N, MacEachern SJ, Saur D, Zakrzewski PK, Cygankiewicz AI, Mokrowiecka A, Małecka-Panas E, Krajewska WM, Liedtke W, Steinhoff MS, Timmermans JP, Bunnett NW, Sharkey KA, Storr MA. Transient receptor potential vanilloid 4 inhibits mouse colonic motility by activating NO-dependent enteric neurotransmission. J Mol Med (Berl) 2015; 93:1297-309. [PMID: 26330151 DOI: 10.1007/s00109-015-1336-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 07/12/2015] [Accepted: 08/17/2015] [Indexed: 01/15/2023]
Abstract
UNLABELLED Recent studies implicate TRPV4 receptors in visceral pain signaling and intestinal inflammation. Our aim was to evaluate the role of TRPV4 in the control of gastrointestinal (GI) motility and to establish the underlying mechanisms. We used immunohistochemistry and PCR to study TRPV4 expression in the GI tract. The effect of TRPV4 activation on GI motility was characterized using in vitro and in vivo motility assays. Calcium and nitric oxide (NO) imaging were performed to study the intracellular signaling pathways. Finally, TRPV4 expression was examined in the colon of healthy human subjects. We demonstrated that TRPV4 can be found on myenteric neurons of the colon and is co-localized with NO synthase (NOS-1). In vitro, the TRPV4 agonist GSK1016790A reduced colonic contractility and increased inhibitory neurotransmission. In vivo, TRPV4 activation slowed GI motility and reduced stool production in mouse models mimicking pathophysiological conditions. We also showed that TRPV4 activation inhibited GI motility by reducing NO-dependent Ca(2+) release from enteric neurons. In conclusion, TRPV4 is involved in the regulation of GI motility in health and disease. KEY MESSAGES • Recent studies implicate TRPV4 in pain signaling and intestinal inflammation. • Our aim was to characterize the role of TRPV4 in the control of GI motility. • We found that TRPV4 activation reduced colonic contractility. • Our studies also showed altered TRPV4 mRNA expression in IBS-C patients. • TRPV4 may be a novel pharmacological target in functional GI diseases.
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Affiliation(s)
- J Fichna
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.,Department of Medicine, Division of Gastroenterology, University of Calgary, Calgary, AB, Canada.,Department of Biochemistry, Medical University of Lodz, Lodz, Poland
| | - D P Poole
- Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.,Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - N Veldhuis
- Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - S J MacEachern
- Department of Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - D Saur
- II Medizinische Klinik, Technische Universität München, Munich, Germany
| | - P K Zakrzewski
- Department of Cytobiochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - A I Cygankiewicz
- Department of Cytobiochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - A Mokrowiecka
- Department of Digestive Tract Diseases, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| | - E Małecka-Panas
- Department of Digestive Tract Diseases, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| | - W M Krajewska
- Department of Cytobiochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - W Liedtke
- Center for Translational Neuroscience, Duke University, Durham, NC, USA
| | - M S Steinhoff
- Department of Dermatology and Surgery, University of California San Francisco, San Francisco, CA, USA
| | - J-P Timmermans
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium
| | - N W Bunnett
- Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.,Department of Pharmacology, The University of Melbourne, Parkville, VIC, Australia
| | - K A Sharkey
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.,Department of Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - M A Storr
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada. .,Department of Medicine, Division of Gastroenterology, University of Calgary, Calgary, AB, Canada. .,Department of Medicine, Division of Gastroenterology, Ludwig Maximilians University of Munich, Marchioninistrasse 15, 81377, Munich, Germany.
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27
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Kaji I, Akiba Y, Said H, Narimatsu K, Kaunitz JD. Luminal 5-HT stimulates colonic bicarbonate secretion in rats. Br J Pharmacol 2015; 172:4655-70. [PMID: 26061462 DOI: 10.1111/bph.13216] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 04/16/2015] [Accepted: 05/09/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE The bioactive monoamine 5-HT, implicated in the pathogenesis of functional gastrointestinal disorders, is abundantly synthesized and stored in rat proximal colonic mucosa and released to the gut lumen and subepithelial space. Despite much data regarding its expression and function, the effects of luminal 5-HT on colonic anion secretion have not been fully investigated. EXPERIMENTAL APPROACH We measured short-circuit current (Isc ) as an indicator of ion transport in mucosa-submucosa or mucosa-only preparations of rat proximal colon. Total CO2 output was measured in vitro and in vivo. Immunohistochemistry was performed to investigate the localization of 5-HT4 , NOS1 and NOS2. KEY RESULTS Luminal 5-HT gradually increased the amplitude and sustained the elevation of Isc . Luminal 5-HT-evoked ΔIsc was acetazolamide sensitive and HCO3 (-) dependent, consistent with cytosolic carbonic anhydrase-dependent electrogenic HCO3 (-) secretion, while not affected by tetrodotoxin (TTX), atropine or indomethacin. Pretreatment with the selective 5-HT4 antagonist GR113808, but not antagonists for 5-HT3 , 5-HT6 or 5-HT7 , inhibited luminal 5-HT-evoked ΔIsc . Furthermore, luminal cisapride and tegaserod increased Isc to the same extent as did 5-HT in the presence of indomethacin and TTX. Removal of the submucosa or pretreatment with NOS inhibitors enhanced luminal 5-HT-evoked ΔIsc , suggesting that NO synthesized in the submucosa suppresses mucosal anion secretion. NOS1 and NOS2 were immunostained in the submucosal neurons and glial cells respectively. Luminal 5-HT-evoked HCO3 (-) secretion was confirmed in vivo, inhibited by co-perfusion of GR113808, but not by ondansetron. CONCLUSIONS AND IMPLICATIONS A novel apical 5-HT4 -mediated HCO3 (-) secretory pathway and an NO-dependent inhibitory mechanism are present in the proximal colon. Luminal 5-HT-evoked HCO3 (-) secretion may be important for the maintenance of mucosal integrity by regulating luminal pH.
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Affiliation(s)
- I Kaji
- Department of Medicine, University of California, Los Angeles, CA, USA.,Brentwood Biomedical Research Institute, Los Angeles, CA, USA
| | - Y Akiba
- Department of Medicine, University of California, Los Angeles, CA, USA.,Brentwood Biomedical Research Institute, Los Angeles, CA, USA.,Greater Los Angeles Veterans Affairs Healthcare System, CA, USA
| | - H Said
- College of Letters and Sciences, University of California, Los Angeles, CA, USA
| | - K Narimatsu
- Department of Medicine, University of California, Los Angeles, CA, USA
| | - J D Kaunitz
- Department of Medicine, University of California, Los Angeles, CA, USA.,Department of Surgery, School of Medicine, University of California, Los Angeles, CA, USA.,Brentwood Biomedical Research Institute, Los Angeles, CA, USA.,Greater Los Angeles Veterans Affairs Healthcare System, CA, USA
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28
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MacEachern SJ, Patel BA, Keenan CM, Dicay M, Chapman K, McCafferty DM, Savidge TC, Beck PL, MacNaughton WK, Sharkey KA. Inhibiting Inducible Nitric Oxide Synthase in Enteric Glia Restores Electrogenic Ion Transport in Mice With Colitis. Gastroenterology 2015; 149:445-55.e3. [PMID: 25865048 PMCID: PMC4516675 DOI: 10.1053/j.gastro.2015.04.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 03/06/2015] [Accepted: 04/06/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Disturbances in the control of ion transport lead to epithelial barrier dysfunction in patients with colitis. Enteric glia regulate intestinal barrier function and colonic ion transport. However, it is not clear whether enteric glia are involved in epithelial hyporesponsiveness. We investigated enteric glial regulation of ion transport in mice with trinitrobenzene sulfonic acid- or dextran sodium sulfate-induced colitis and in Il10(-/-) mice. METHODS Electrically evoked ion transport was measured in full-thickness segments of colon from CD1 and Il10(-/-) mice with or without colitis in Ussing chambers. Nitric oxide (NO) production was assessed using amperometry. Bacterial translocation was investigated in the liver, spleen, and blood of mice. RESULTS Electrical stimulation of the colon evoked a tetrodotoxin-sensitive chloride secretion. In mice with colitis, ion transport almost completely disappeared. Inhibiting inducible NO synthase (NOS2), but not neuronal NOS (NOS1), partially restored the evoked secretory response. Blocking glial function with fluoroacetate, which is not a NOS2 inhibitor, also partially restored ion transport. Combined NOS2 inhibition and fluoroacetate administration fully restored secretion. Epithelial responsiveness to vasoactive intestinal peptide was increased after enteric glial function was blocked in mice with colitis. In colons of mice without colitis, NO was produced in the myenteric plexus almost completely via NOS1. NO production was increased in mice with colitis, compared with mice without colitis; a substantial proportion of NOS2 was blocked by fluoroacetate administration. Inhibition of enteric glial function in vivo reduced the severity of trinitrobenzene sulfonic acid-induced colitis and associated bacterial translocation. CONCLUSIONS Increased production of NOS2 in enteric glia contributes to the dysregulation of intestinal ion transport in mice with colitis. Blocking enteric glial function in these mice restores epithelial barrier function and reduces bacterial translocation.
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Affiliation(s)
- Sarah J. MacEachern
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Bhavik A. Patel
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Huxley Building, Brighton, UK
| | - Catherine M. Keenan
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Michael Dicay
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Kevin Chapman
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Donna-Marie McCafferty
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Tor C. Savidge
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
| | - Paul L. Beck
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Wallace K. MacNaughton
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Keith A. Sharkey
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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29
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Neunlist M, Rolli-Derkinderen M, Latorre R, Van Landeghem L, Coron E, Derkinderen P, De Giorgio R. Enteric glial cells: recent developments and future directions. Gastroenterology 2014; 147:1230-7. [PMID: 25305504 DOI: 10.1053/j.gastro.2014.09.040] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 09/11/2014] [Accepted: 09/12/2014] [Indexed: 12/12/2022]
Abstract
Since their discovery at the end of the 19th century, enteric glial cells (EGCs), the major cellular component of the enteric nervous system, have long been considered mere supportive cells for neurons. However, recent evidence has challenged this view and highlighted their central role in the regulation of gut homeostasis as well as their implication in digestive and extradigestive diseases. In this review, we summarize emerging concepts as to how EGCs regulate neuromediator expression, exert neuroprotective roles, and even act as neuronal as well as glial progenitors in the enteric nervous system. A particularly crucial property of EGCs is their ability to maintain the integrity of the intestinal epithelial barrier, a role that may have important clinical implications not only for digestive diseases, such as postoperative ileus and inflammatory bowel diseases, but also for extradigestive diseases, such as Parkinson disease or obesity. EGCs could also contribute directly to disease processes (eg, inflammation) by their ability to secrete chemokines/cytokines in response to bacterial or inflammatory challenges. Defining the pleiotropic roles exerted by EGCs may reveal better knowledge and help develop new targeted therapeutic options for a variety of gastrointestinal diseases.
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Affiliation(s)
- Michel Neunlist
- INSERM Unité 913, Nantes, France; Université Nantes, Nantes, France; CHU Nantes, Hôtel Dieu, Institut des Maladies de l'Appareil Digestif, Nantes, France.
| | - Malvyne Rolli-Derkinderen
- INSERM Unité 913, Nantes, France; Université Nantes, Nantes, France; CHU Nantes, Hôtel Dieu, Institut des Maladies de l'Appareil Digestif, Nantes, France
| | - Rocco Latorre
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Laurianne Van Landeghem
- INSERM Unité 913, Nantes, France; Université Nantes, Nantes, France; CHU Nantes, Hôtel Dieu, Institut des Maladies de l'Appareil Digestif, Nantes, France
| | - Emmanuel Coron
- INSERM Unité 913, Nantes, France; Université Nantes, Nantes, France; CHU Nantes, Hôtel Dieu, Institut des Maladies de l'Appareil Digestif, Nantes, France
| | - Pascal Derkinderen
- INSERM Unité 913, Nantes, France; Université Nantes, Nantes, France; CHU Nantes, Hôtel Dieu, Institut des Maladies de l'Appareil Digestif, Nantes, France; Department of Neurology, CHU Nantes, Nantes, France
| | - Roberto De Giorgio
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
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30
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Boesmans W, Lasrado R, Vanden Berghe P, Pachnis V. Heterogeneity and phenotypic plasticity of glial cells in the mammalian enteric nervous system. Glia 2014; 63:229-41. [PMID: 25161129 DOI: 10.1002/glia.22746] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 08/05/2014] [Indexed: 12/24/2022]
Abstract
Enteric glial cells are vital for the autonomic control of gastrointestinal homeostasis by the enteric nervous system. Several different functions have been assigned to enteric glial cells but whether these are performed by specialized subtypes with a distinctive phenotype and function remains elusive. We used Mosaic Analysis with Double Markers and inducible lineage tracing to characterize the morphology and dynamic molecular marker expression of enteric GLIA in the myenteric plexus. Functional analysis in individually identified enteric glia was performed by Ca(2+) imaging. Our experiments have identified four morphologically distinct subpopulations of enteric glia in the gastrointestinal tract of adult mice. Marker expression analysis showed that the majority of glia in the myenteric plexus co-express glial fibrillary acidic protein (GFAP), S100β, and Sox10. However, a considerable fraction (up to 80%) of glia outside the myenteric ganglia, did not label for these markers. Lineage tracing experiments suggest that these alternative combinations of markers reflect dynamic gene regulation rather than lineage restrictions. At the functional level, the three myenteric glia subtypes can be distinguished by their differential response to adenosine triphosphate. Together, our studies reveal extensive heterogeneity and phenotypic plasticity of enteric glial cells and set a framework for further investigations aimed at deciphering their role in digestive function and disease.
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Affiliation(s)
- Werend Boesmans
- Laboratory for Enteric NeuroScience (LENS), TARGID, Department of Clinical and Experimental Medicine, University of Leuven, Leuven, Belgium
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31
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Importance of NO and its related compounds in enteric nervous system regulation of gut homeostasis and disease susceptibility. Curr Opin Pharmacol 2014; 19:54-60. [PMID: 25108170 DOI: 10.1016/j.coph.2014.07.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 07/15/2014] [Accepted: 07/18/2014] [Indexed: 12/13/2022]
Abstract
Nitric oxide (NO) produced by the enteric nervous system represents an important regulatory mechanism in gut homeostasis. Aberrant NO signaling contributes significantly toward enteric disease by altering gut motility, vascular tone, blood supply, mucosal barrier function, secretions and immunity. Consequently, there is much interest in therapeutically targeting NO production and its bioactive intermediates. This article highlights recent advances in NO signaling and therapeutics as it relates to the gastrointestinal tract and its associated NO producing microbiota. Because of its limited scope, a particular emphasis is placed on S-nitrosylation as the emerging physiologic mechanism for NO signal transduction, and how such signals are modulated by other gaseous transmitters - notably hydrogen disulfide and carbon monoxide - that are produced by the enteric nervous system and share common molecular targets. Recent findings also indicate that druggable regulators of S-nitrosylation, for example S-nitrosoglutathione (GSNO) reductase, provide for a superior pharmacology and finer therapeutic control over classical NO donors, and may be better suited for oral delivery to the gastrointestinal tract.
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32
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Lies B, Groneberg D, Friebe A. Toward a better understanding of gastrointestinal nitrergic neuromuscular transmission. Neurogastroenterol Motil 2014; 26:901-12. [PMID: 24827638 DOI: 10.1111/nmo.12367] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 04/21/2014] [Indexed: 12/30/2022]
Abstract
BACKGROUND Nitric oxide (NO) is an important inhibitory neurotransmitter in the gastrointestinal (GI) tract. The majority of nitrergic effects are transduced by NO-sensitive guanylyl cyclase (NO-GC) as the receptor for NO, and, thus, mediated by cGMP-dependent mechanisms. Work carried out during the past years has demonstrated NO to be largely involved in GI smooth muscle relaxation and motility. However, detailed investigation of nitrergic signaling has turned out to be complicated as NO-GC was identified in several different GI cell types such as smooth muscle cells, interstitial cells of Cajal and fibroblast-like cells. With regards to nitrergic neurotransmission, special focus has been placed on the role of interstitial cells of Cajal using mutant mice with reduced populations of ICC. Recently, global and cell-specific knockout mice for enzymes participating in nitrergic signaling have been generated providing a suitable approach to further examine the role of NO-mediated signaling in GI smooth muscle. PURPOSE This review discusses the current knowledge on nitrergic mechanisms in gastrointestinal neuromuscular transmission with a focus on genetic models and outlines possible further investigations to gain better understanding on NO-mediated effects in the GI tract.
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Affiliation(s)
- B Lies
- Physiologisches Institut I, Universität Würzburg, Würzburg, Germany
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33
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Cheadle GA, Costantini TW, Bansal V, Eliceiri BP, Coimbra R. Cholinergic signaling in the gut: a novel mechanism of barrier protection through activation of enteric glia cells. Surg Infect (Larchmt) 2014; 15:387-93. [PMID: 24828283 DOI: 10.1089/sur.2013.103] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Enteric glia cells (EGCs) play an important role in maintaining proper intestinal barrier function. We have shown that vagal nerve stimulation (VNS) increases EGC activation, which is associated with better gut barrier integrity. Enteric neurons communicate with EGCs through nicotinic cholinergic signaling, which may represent a pathway by which VNS activates EGCs. This study sought to define further the mechanism by which VNS prevents intestinal barrier failure using an in vitro model. We hypothesized that a nicotinic cholinergic agonist would increase EGC activation, prevent intestinal nuclear factor kappa-B (NF-κB) activation, and result in better intestinal barrier function. METHODS Cultured EGCs were exposed to the nicotinic cholinergic agonist nicotine. Expression of glial fibrillary acidic protein (GFAP) was measured by immunoblot to determine changes in EGC activation. Caco-2 cells were grown to confluence and incubated alone or in co-culture with EGCs. Cells were then stimulated with Cytomix for 24 h in the presence or absence of nicotine, and barrier integrity was assessed by permeability to 4-kDa FITC-dextran. Changes in phosphorylated inhibitor of NF-κb (P-IκBα) and phosphorylated NF-κB (P-NF-κB) were assessed by immunoblot. RESULTS Stimulation with nicotine resulted in EGC activation, as demonstrated by an increase in GFAP expression. Cytomix stimulation increased permeability in Caco-2 cells cultured alone or with EGCs. Treatment of stimulated Caco-2/EGC co-cultures with nicotine reduced permeability similar to control. Nicotine failed to prevent barrier permeability in Caco-2 cells alone. Co-culture of stimulated Caco-2 cells with nicotine-activated EGCs prevented Cytomix-induced increases in P-IκBα and P-NF-κB expression. CONCLUSION A pharmacologic nicotinic cholinergic agonist increased EGC activation and improved intestinal epithelial barrier function in an in vitro model of intestinal injury. Nicotine-activated EGCs appear to modulate barrier function by preventing the activation of the NF-κB pathway. Therapies aimed at activating EGCs may have important clinical applications for improving intestinal barrier function after injury.
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Affiliation(s)
- Gerald A Cheadle
- Division of Trauma, Surgical Critical Care, and Burns, Department of Surgery, University of California San Diego Health Sciences , San Diego, California
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Sharkey KA, Savidge TC. Reprint of: Role of enteric neurotransmission in host defense and protection of the gastrointestinal tract. Auton Neurosci 2014; 182:70-82. [PMID: 24674836 DOI: 10.1016/j.autneu.2014.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 12/11/2013] [Indexed: 12/11/2022]
Abstract
Host defense is a vital role played by the gastrointestinal tract. As host to an enormous and diverse microbiome, the gut has evolved an elaborate array of chemical and physicals barriers that allow the digestion and absorption of nutrients without compromising the mammalian host. The control of such barrier functions requires the integration of neural, humoral, paracrine and immune signaling, involving redundant and overlapping mechanisms to ensure, under most circumstances, the integrity of the gastrointestinal epithelial barrier. Here we focus on selected recent developments in the autonomic neural control of host defense functions used in the protection of the gut from luminal agents, and discuss how the microbiota may potentially play a role in enteric neurotransmission. Key recent findings include: the important role played by subepithelial enteric glia in modulating intestinal barrier function, identification of stress-induced mechanisms evoking barrier breakdown, neural regulation of epithelial cell proliferation, the role of afferent and efferent vagal pathways in regulating barrier function, direct evidence for bacterial communication to the enteric nervous system, and microbial sources of enteric neurotransmitters. We discuss these new and interesting developments in our understanding of the role of the autonomic nervous system in gastrointestinal host defense.
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Affiliation(s)
- Keith A Sharkey
- Hotchkiss Brain Institute and Snyder Institute for Chronic Diseases, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada.
| | - Tor C Savidge
- Texas Children's Microbiome Center, Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
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35
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Role of enteric neurotransmission in host defense and protection of the gastrointestinal tract. Auton Neurosci 2013; 181:94-106. [PMID: 24412639 DOI: 10.1016/j.autneu.2013.12.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 12/11/2013] [Indexed: 12/24/2022]
Abstract
Host defense is a vital role played by the gastrointestinal tract. As host to an enormous and diverse microbiome, the gut has evolved an elaborate array of chemical and physicals barriers that allow the digestion and absorption of nutrients without compromising the mammalian host. The control of such barrier functions requires the integration of neural, humoral, paracrine and immune signaling, involving redundant and overlapping mechanisms to ensure, under most circumstances, the integrity of the gastrointestinal epithelial barrier. Here we focus on selected recent developments in the autonomic neural control of host defense functions used in the protection of the gut from luminal agents, and discuss how the microbiota may potentially play a role in enteric neurotransmission. Key recent findings include: the important role played by subepithelial enteric glia in modulating intestinal barrier function, identification of stress-induced mechanisms evoking barrier breakdown, neural regulation of epithelial cell proliferation, the role of afferent and efferent vagal pathways in regulating barrier function, direct evidence for bacterial communication to the enteric nervous system, and microbial sources of enteric neurotransmitters. We discuss these new and interesting developments in our understanding of the role of the autonomic nervous system in gastrointestinal host defense.
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36
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Boesmans W, Martens MA, Weltens N, Hao MM, Tack J, Cirillo C, Vanden Berghe P. Imaging neuron-glia interactions in the enteric nervous system. Front Cell Neurosci 2013; 7:183. [PMID: 24155689 PMCID: PMC3801083 DOI: 10.3389/fncel.2013.00183] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 10/01/2013] [Indexed: 12/13/2022] Open
Abstract
The enteric nervous system (ENS) is a network of neurons and glia within the wall of the gastrointestinal tract that is able to control many aspects of digestive function independently from the central nervous system. Enteric glial cells share several features with astrocytes and are closely associated with enteric neurons and their processes both within enteric ganglia, and along interconnecting fiber bundles. Similar to other parts of the nervous system, there is communication between enteric neurons and glia; enteric glial cells can detect neuronal activity and have the machinery to intermediate neurotransmission. However, due to the close contact between these two cell types and the particular characteristics of the gut wall, the recording of enteric glial cell activity in live imaging experiments, especially in the context of their interaction with neurons, is not straightforward. Most studies have used calcium imaging approaches to examine enteric glial cell activity but in many cases, it is difficult to distinguish whether observed transients arise from glial cells, or neuronal processes or varicosities in their vicinity. In this technical report, we describe a number of approaches to unravel the complex neuron-glia crosstalk in the ENS, focusing on the challenges and possibilities of live microscopic imaging in both animal models and human tissue samples.
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Affiliation(s)
- Werend Boesmans
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for GastroIntestinal Disorders, University of Leuven , Leuven, Belgium ; Translational Research Center for GastroIntestinal Disorders (TARGID), Department of Clinical and Experimental Medicine, University of Leuven , Leuven, Belgium
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37
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Wang X, Lippi G, Carlson DM, Berg DK. Activation of α7-containing nicotinic receptors on astrocytes triggers AMPA receptor recruitment to glutamatergic synapses. J Neurochem 2013; 127:632-43. [PMID: 24032433 DOI: 10.1111/jnc.12436] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 07/31/2013] [Accepted: 08/26/2013] [Indexed: 02/02/2023]
Abstract
Astrocytes, an abundant form of glia, are known to promote and modulate synaptic signaling between neurons. They also express α7-containing nicotinic acetylcholine receptors (α7-nAChRs), but the functional relevance of these receptors is unknown. We show here that stimulation of α7-nAChRs on astrocytes releases components that induce hippocampal neurons to acquire more α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors post-synaptically at glutamatergic synapses. The increase is specific in that no change is seen in synaptic NMDA receptor clusters or other markers for glutamatergic synapses, or in markers for GABAergic synapses. Moreover, the increases in AMPA receptors on the neuron surface are accompanied by increases in the frequency of spontaneous miniature synaptic currents mediated by the receptors and increases in the ratio of evoked synaptic currents mediated by AMPA versus NMDA receptors. This suggests that stimulating α7-nAChRs on astrocytes can convert 'silent' glutamatergic synapses to functional status. Astrocyte-derived thrombospondin is necessary but not sufficient for the effect, while tumor necrosis factor-α is sufficient but not necessary. The results identify astrocyte α7-nAChRs as a novel pathway through which nicotinic cholinergic signaling can promote the development of glutamatergic networks, recruiting AMPA receptors to post-synaptic sites and rendering the synapses more functional. We find that activation of nicotinic receptors on astrocytes releases a component that specifically recruits AMPA receptors to glutamatergic synapses. The recruitment appears to occur preferentially at what may be 'silent synapses', that is, synapses that have all the components required for glutamatergic transmission (including NMDA receptors) but lack sufficient AMPA receptors to generate a response. The results are unexpected and open up new possibilities for mechanisms underlying network formation and synaptic plasticity.
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Affiliation(s)
- Xulong Wang
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, California, USA
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Enteric glia cells attenuate cytomix-induced intestinal epithelial barrier breakdown. PLoS One 2013; 8:e69042. [PMID: 23840906 PMCID: PMC3698076 DOI: 10.1371/journal.pone.0069042] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 06/04/2013] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Intestinal barrier failure may lead to systemic inflammation and distant organ injury in patients following severe injury. Enteric glia cells (EGCs) have been shown to play an important role in maintaining gut barrier integrity through secretion of S-Nitrosoglutathione (GSNO). We have recently shown than Vagal Nerve Stimulation (VNS) increases EGC activation, which was associated with improved gut barrier integrity. Thus, we sought to further study the mechanism by which EGCs prevent intestinal barrier breakdown utilizing an in vitro model. We postulated that EGCs, through the secretion of GSNO, would improve intestinal barrier function through improved expression and localization of intestinal tight junction proteins. METHODS Epithelial cells were co-cultured with EGCs or incubated with GSNO and exposed to Cytomix (TNF-α, INF-γ, IL-1β) for 24 hours. Barrier function was assessed by permeability to 4kDa FITC-Dextran. Changes in tight junction proteins ZO-1, occludin, and phospho-MLC (P-MLC) were assessed by immunohistochemistry and immunoblot. KEY RESULTS Co-culture of Cytomix-stimulated epithelial monolayers with EGCs prevented increases in permeability and improved expression and localization of occludin, ZO-1, and P-MLC. Further, treatment of epithelial monolayers with GSNO also prevented Cytomix-induced increases in permeability and exhibited a similar improvement in expression and localization of occludin, ZO-1, and P-MLC. CONCLUSIONS & INFERENCES The addition of EGCs, or their secreted mediator GSNO, prevents epithelial barrier failure after injury and improved expression of tight junction proteins. Thus, therapies that increase EGC activation, such as VNS, may be a novel strategy to limit barrier failure in patients following severe injury.
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Stenkamp-Strahm C, Patterson S, Boren J, Gericke M, Balemba O. High-fat diet and age-dependent effects on enteric glial cell populations of mouse small intestine. Auton Neurosci 2013; 177:199-210. [PMID: 23726157 DOI: 10.1016/j.autneu.2013.04.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 04/26/2013] [Accepted: 04/29/2013] [Indexed: 02/09/2023]
Abstract
Diabetes and obesity are increasing in prevalence at an alarming rate throughout the world. Autonomic diabetic neuropathy is evident in individuals that experience a long-standing diabetic disease state, and gastrointestinal (GI) dysmotility is thought to be the outcome of neuropathies within the enteric nervous system (ENS) of these patients. To date, an analysis of enteric glial cell population changes during diabetic symptoms has not been performed, and may bring insight into disease pathology and neuropathy, given glial cell implications in gastrointestinal and neuronal homeostasis. Diabetes and obesity were monitored in C57Bl/6J mice fed a 72% high-fat diet, and duodenal glial expression patterns were evaluated by immunohistochemistry and RT-PCR for S100β, Sox10 and GFAP proteins and transcripts, as well as transmission electron microscopy (TEM). The high-fat diet caused obesity, hyperglycemia and insulin resistance after 4 weeks. These changes were associated with a significant decline in the area density indices of mucosa-associated glial cell networks, evidenced by S100β staining at 8 and 20 weeks. All three markers and TEM showed that myenteric glial cells were unaffected by early and late disease periods. However, analysis of Sox10 transcript expression and immunoreactivity showed a diet independent, age-associated decline in glial cell populations. This is the first study showing that mucosal glia cell damage occurs during diabetic symptoms, suggesting that mucosal enteric glia injury may have a pathophysiological significance during this disease. Our results also provide support for age-associated changes in longitudinal studies of enteric glial cells.
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Neunlist M, Van Landeghem L, Mahé MM, Derkinderen P, des Varannes SB, Rolli-Derkinderen M. The digestive neuronal-glial-epithelial unit: a new actor in gut health and disease. Nat Rev Gastroenterol Hepatol 2013; 10:90-100. [PMID: 23165236 DOI: 10.1038/nrgastro.2012.221] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The monolayer of columnar epithelial cells lining the gastrointestinal tract--the intestinal epithelial barrier (IEB)--is the largest exchange surface between the body and the external environment. The permeability of the IEB has a central role in the regulation of fluid and nutrient intake as well as in the control of the passage of pathogens. The functions of the IEB are highly regulated by luminal as well as internal components, such as bacteria or immune cells, respectively. Evidence indicates that two cell types of the enteric nervous system (ENS), namely enteric neurons and enteric glial cells, are potent modulators of IEB functions, giving rise to the novel concept of a digestive 'neuronal-glial-epithelial unit' akin to the neuronal-glial-endothelial unit in the brain. In this Review, we summarize findings demonstrating that the ENS is a key regulator of IEB function and is actively involved in pathologies associated with altered barrier function.
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Affiliation(s)
- Michel Neunlist
- INSERM UMR913, Institut des Maladies de l'Appareil Digestif, Université de Nantes, CHU Hôtel Dieu, 1 place Alexis Ricordeau, 44093 Nantes, France.
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Boesmans W, Cirillo C, Van den Abbeel V, Van den Haute C, Depoortere I, Tack J, Vanden Berghe P. Neurotransmitters involved in fast excitatory neurotransmission directly activate enteric glial cells. Neurogastroenterol Motil 2013; 25:e151-60. [PMID: 23279281 DOI: 10.1111/nmo.12065] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND The intimate association between glial cells and neurons within the enteric nervous system has confounded careful examination of the direct responsiveness of enteric glia to different neuroligands. Therefore, we aimed to investigate whether neurotransmitters known to elicit fast excitatory potentials in enteric nerves also activate enteric glia directly. METHODS We studied the effect of acetylcholine (ACh), serotonin (5-HT), and adenosine triphosphate (ATP) on intracellular Ca(2+) signaling using aequorin-expressing and Fluo-4 AM-loaded CRL-2690 rat and human enteric glial cell cultures devoid of neurons. The influence of these neurotransmitters on the proliferation of glia was measured and their effect on the expression of c-Fos as well as glial fibrillary acidic protein (GFAP), Sox10, and S100 was examined by immunohistochemistry and quantitative RT-PCR. KEY RESULTS Apart from ATP, also ACh and 5-HT induced a dose-dependent increase in intracellular Ca(2+) concentration in CRL-2690 cells. Similarly, these neurotransmitters also evoked Ca(2+) transients in human primary enteric glial cells obtained from mucosal biopsies. In contrast with ATP, stimulation with ACh and 5-HT induced early gene expression in CRL-2690 cells. The proliferation of enteric glia and their expression of GFAP, Sox10, and S100 were not affected following stimulation with these neurotransmitters. CONCLUSIONS & INFERENCES We provide evidence that enteric glial cells respond to fast excitatory neurotransmitters by changes in intracellular Ca(2+). On the basis of our experimental in vitro setting, we show that enteric glia are not only directly responsive to purinergic but also to serotonergic and cholinergic signaling mechanisms.
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Affiliation(s)
- W Boesmans
- Laboratory of Enteric NeuroScience, KU Leuven, Leuven, Belgium
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Gulbransen BD, Sharkey KA. Novel functional roles for enteric glia in the gastrointestinal tract. Nat Rev Gastroenterol Hepatol 2012; 9:625-32. [PMID: 22890111 DOI: 10.1038/nrgastro.2012.138] [Citation(s) in RCA: 265] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Enteric glia are a unique class of peripheral glial cells within the gastrointestinal tract. Major populations of enteric glia are found in enteric ganglia in the myenteric and submucosal plexuses of the enteric nervous system (ENS); these cells are also found outside of the ENS, within the circular muscle and in the lamina propria of the mucosa. These different populations of cells probably represent unique classes of glial cells with differing functions. In the past few years, enteric glia have been found to be involved in almost every gut function including motility, mucosal secretion and host defence. Subepithelial glia seem to have a trophic and supporting relationship with intestinal epithelial cells, but the necessity of these roles in the maintenance of normal epithelial functions remains to be shown. Likewise, glia within enteric ganglia are activated by synaptic stimulation, suggesting an active role in synaptic transmission, but the precise role of glial activation in normal enteric network activity is unclear. Excitingly, enteric glia can also give rise to new neurons, but seemingly only under limited circumstances. In this Review, we discuss the current body of evidence supporting functional roles of enteric glia and identify key gaps in our understanding of the physiology of these unique cells.
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Affiliation(s)
- Brian D Gulbransen
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive North West Calgary, AB T2N 4N1, Canada
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Martin GR, Alvarez AL, Bashashati M, Keenan CM, Jirik FR, Sharkey KA. Endogenous cellular prion protein regulates contractility of the mouse ileum. Neurogastroenterol Motil 2012; 24:e412-24. [PMID: 22762267 DOI: 10.1111/j.1365-2982.2012.01970.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Cellular prion protein (PrP(C) ) is expressed in the enteric nervous system (ENS), however, its physiological role has not been identified. Studies suggest that PrP(C) can function as a metal-binding protein, as absence of the protein has been linked to altered copper metabolism and atypical synaptic activity. Because copper is known to modulate smooth muscle relaxation, we tested the hypothesis that PrP(C) deficiency would alter intestinal contractility. METHODS We examined electrically evoked ileal contractility in Prnp(-/-) or wild type littermate mice and the effects of copper or copper chelation. PrP(C) expression was studied in whole mount ileal preparations of mice and guinea pigs by immunohistochemistry. KEY RESULTS Relative to wild type mice, ileal tissues of Prnp(-/-) mice exhibited reduced electrical field stimulation (EFS)-evoked contractility. Furthermore, EFS-induced relaxation, as a percentage of that induced by a nitric oxide donor, was enhanced. Addition of a copper donor to the organ bath increased, whereas the addition of a copper chelator inhibited, nitric oxide donor-induced ileal relaxation in Prnp(-/-) mice. PrP(C) was expressed on nerve fibers or terminals, and some cell bodies in the myenteric and submucosal plexuses of wild type mice. PrP(C) colocalized with a neuron-specific ectonucleotidase, nucleoside triphosphate diphosphohydrolase 3 (NTPDase3), but to only a limited extent with GFAP, a marker of enteric glia. Guinea pigs expressed PrP(C) in nerve fibers or terminals and enteric glia in the myenteric and submucosal plexuses. CONCLUSIONS & INFERENCES Our findings suggest that PrP(C) , which is abundant in the ENS, has a role in the regulation of ileal contractility.
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Affiliation(s)
- G R Martin
- Hotchkiss Brain Institute and Snyder Institute for Chronic Diseases, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.
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Bagyánszki M, Bódi N. Diabetes-related alterations in the enteric nervous system and its microenvironment. World J Diabetes 2012; 3:80-93. [PMID: 22645637 PMCID: PMC3360223 DOI: 10.4239/wjd.v3.i5.80] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 04/06/2012] [Accepted: 05/11/2012] [Indexed: 02/05/2023] Open
Abstract
Gastric intestinal symptoms common among diabetic patients are often caused by intestinal motility abnormalities related to enteric neuropathy. It has recently been demonstrated that the nitrergic subpopulation of myenteric neurons are especially susceptible to the development of diabetic neuropathy. Additionally, different susceptibility of nitrergic neurons located in different intestinal segments to diabetic damage and their different levels of responsiveness to insulin treatment have been revealed. These findings indicate the importance of the neuronal microenvironment in the pathogenesis of diabetic nitrergic neuropathy. The main focus of this review therefore was to summarize recent advances related to the diabetes-related selective nitrergic neuropathy and associated motility disturbances. Special attention was given to the findings on capillary endothelium and enteric glial cells. Growing evidence indicates that capillary endothelium adjacent to the myenteric ganglia and enteric glial cells surrounding them are determinative in establishing the ganglionic microenvironment. Additionally, recent advances in the development of new strategies to improve glycemic control in type 1 and type 2 diabetes mellitus are also considered in this review. Finally, looking to the future, the recent and promising results of metagenomics for the characterization of the gut microbiome in health and disease such as diabetes are highlighted.
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Affiliation(s)
- Mária Bagyánszki
- Mária Bagyánszki, Nikolett Bódi, Department of Physiology, Anatomy and Neuroscience, Faculty of Science, University of Szeged, H-6726 Szeged, Hungary
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Affiliation(s)
- Tor C Savidge
- Department of Gastroenterology and Hepatology, University of Texas Medical Branch, Galveston, TX, USA.
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Hoffman JM, Tyler K, MacEachern SJ, Balemba OB, Johnson AC, Brooks EM, Zhao H, Swain GM, Moses PL, Galligan JJ, Sharkey KA, Greenwood-Van Meerveld B, Mawe GM. Activation of colonic mucosal 5-HT(4) receptors accelerates propulsive motility and inhibits visceral hypersensitivity. Gastroenterology 2012; 142:844-854.e4. [PMID: 22226658 PMCID: PMC3477545 DOI: 10.1053/j.gastro.2011.12.041] [Citation(s) in RCA: 209] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 12/07/2011] [Accepted: 12/13/2011] [Indexed: 12/19/2022]
Abstract
BACKGROUND & AIMS 5-hydroxytryptamine receptor (5-HT(4)R) agonists promote gastrointestinal motility and attenuate visceral pain, but concerns about adverse reactions have restricted their availability. We tested the hypotheses that 5-HT(4) receptors are expressed in the colonic epithelium and that 5-HT(4)R agonists can act intraluminally to increase motility and reduce visceral hypersensitivity. METHODS Mucosal expression of the 5-HT(4)R was evaluated by reverse-transcriptase polymerase chain reaction and immunohistochemical analysis of tissues from 5-HT(4)R(BAC)-enhanced green fluorescent protein mice. Amperometry, histology, and short-circuit current measurements were used to study 5-HT, mucus, and Cl(-) secretion, respectively. Propulsive motility was measured in guinea pig distal colon, and visceromotor responses were recorded in a rat model of colonic hypersensitivity. 5-HT(4)R compounds included cisapride, tegaserod, naronapride, SB204070, and GR113808. RESULTS Mucosal 5-HT(4) receptors were present in the small and large intestines. In the distal colon, 5-HT(4) receptors were expressed by most epithelial cells, including enterochromaffin and goblet cells. Stimulation of 5-HT(4)Rs evoked mucosal 5-HT release, goblet cell degranulation, and Cl(-) secretion. Luminal administration of 5-HT(4)R agonists accelerated propulsive motility; a 5-HT(4)R antagonist blocked this effect. Bath application of 5-HT(4)R agonists did not affect motility. Oral or intracolonic administration of 5-HT(4)R agonists attenuated visceral hypersensitivity. Intracolonic administration was more potent than oral administration, and was inhibited by a 5-HT(4)R antagonist. CONCLUSIONS Mucosal 5-HT(4) receptor activation can mediate the prokinetic and antinociceptive actions of 5-HT(4)R agonists. Colon-targeted, intraluminal delivery of 5-HT(4)R agonists might be used to promote motility and alleviate visceral pain, while restricting systemic bioavailability and resulting adverse side effects.
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MESH Headings
- Administration, Oral
- Analgesics/administration & dosage
- Analgesics/pharmacology
- Animals
- Chlorides/metabolism
- Chromosomes, Artificial, Bacterial
- Colon/drug effects
- Colon/innervation
- Colon/metabolism
- Disease Models, Animal
- Enterochromaffin Cells/drug effects
- Enterochromaffin Cells/metabolism
- Gastrointestinal Agents/administration & dosage
- Gastrointestinal Agents/pharmacology
- Gastrointestinal Motility/drug effects
- Goblet Cells/drug effects
- Goblet Cells/metabolism
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Guinea Pigs
- Humans
- Hyperalgesia/metabolism
- Hyperalgesia/physiopathology
- Hyperalgesia/prevention & control
- Immunohistochemistry
- Intestinal Mucosa/drug effects
- Intestinal Mucosa/innervation
- Intestinal Mucosa/metabolism
- Male
- Membrane Potentials
- Mice
- Mice, Inbred BALB C
- Mice, Transgenic
- Mucus/metabolism
- Pain/metabolism
- Pain/physiopathology
- Pain/prevention & control
- Pain Threshold/drug effects
- Pressure
- Rats
- Rats, Sprague-Dawley
- Receptors, Serotonin, 5-HT4/drug effects
- Receptors, Serotonin, 5-HT4/genetics
- Receptors, Serotonin, 5-HT4/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Serotonin/metabolism
- Serotonin 5-HT4 Receptor Agonists/administration & dosage
- Serotonin 5-HT4 Receptor Agonists/pharmacology
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Affiliation(s)
- Jill M Hoffman
- Department of Anatomy & Neurobiology, University of Vermont, Burlington, Vermont 05405, USA
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Broadhead MJ, Bayguinov PO, Okamoto T, Heredia DJ, Smith TK. Ca2+ transients in myenteric glial cells during the colonic migrating motor complex in the isolated murine large intestine. J Physiol 2011; 590:335-50. [PMID: 22063626 DOI: 10.1113/jphysiol.2011.219519] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Enteric glia cells (EGCs) form a dense network around myenteric neurons in a ganglia and are likely to have not only a supportive role but may also regulate or be regulated by neural activity. Our aims were to determine if EGCs are activated during the colonic migrating motor complex (CMMC) in the isolated murine colon. Strips of longitudinal muscle were removed and Ca(2+) imaging (Fluo-4) used to study activity in EGCs within myenteric ganglia during CMMCs, followed by post hoc S100 staining to reveal EGCs. The cell bodies of EGCs and their processes formed caps and halos, respectively, around some neighbouring myenteric neurons. Some EGCs (36%), which were largely quiescent between CMMCs, exhibited prolonged tetrodotoxin (TTX; 1 μm)-sensitive Ca(2+) transients that peaked ∼39 s following a mucosal stimulus that generated the CMMC, and often outlasted the CMMC (duration ∼23 s). Ca(2+) transients in EGCs often varied in duration within a ganglion; however, the duration of these transients was closely matched by activity in closely apposed nerve varicosities, suggesting EGCs were not only innervated but the effective innervation was localized. Furthermore, all EGCs, even those that were quiescent, responded with robust Ca(2+) transients to KCl, caffeine, nicotine, substance P and GR 64349 (an NK2 agonist), suggesting they were adequately loaded with indicator and that some EGCs may be inhibited by substances released by neighbouring neurons. Intracellular Ca(2+) waves were visualised propagating between closely apposed glia and from glial cell processes to the soma (velocity 12 μm s(-1)) where they produced an accumulative rise in Ca(2+), suggesting that the soma acts as an integrator of Ca(2+) activity. In conclusion, Ca(2+) transients in EGCs occur secondary to nerve activity; their activation is driven by intrinsic excitatory nerve pathways that generate the CMMC.
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Affiliation(s)
- Matthew J Broadhead
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA.
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Sharkey KA. Tyrosine hydroxylase in the stalk-median eminence and posterior pituitary is inactivated only during the plateau phase of the preovulatory prolactin surge. Endocrinology 1989; 125:918-25. [PMID: 25689252 DOI: 10.1172/jci76303] [Citation(s) in RCA: 132] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This study examined changes in the activity of tyrosine hydroxylase (TH) in the stalk-median eminence (SME) and posterior pituitary (PP) during the preovulatory PRL surge. Immature female rats were injected with PMSG on day 28. Blood PRL levels were low on the morning of day 30, rose to a peak from 1400-1600 h, remained at a lower plateau from 1800-2400 h, and declined to basal levels on the morning of day 31. SME, PP, and striatum were removed from PMSG-treated rats at selected times during the periovulatory period and from age-matched control rats. TH activity was determined in tissue homogenates by a coupled hydroxylation-decarboxylation assay. Apparent Km and maximum velocity values with respect to 6-methyl tetrahydropterine were estimated from substrate saturation curves. The kinetic parameters for TH in either the SME or the PP of control rats were similar at 1100 and 1800 h on day 30. However, the apparent Km in both tissues was significantly lower than that in the striatum. The affinity of TH in the SME and PP was unchanged before and during the peak phase of the PRL surge, reduced significantly during the late plateau, and returned to presurge levels in the morning of day 31. TH activity in the striatum was similar at all times examined. To determine the state of activation of the enzyme, tissue homogenates were preincubated with cAMP, ATP, and magnesium. TH activity in the SME during the peak phase was unchanged by cAMP, and that in the PP was modestly increased. The relatively inactive enzyme in both tissues during the plateau phase was markedly activated by a cAMP-dependent mechanism. The low affinity of striatal TH was greatly increased by cAMP at both times. These data suggest that TH in the SME and PP exists in an activated state most of the time and is transiently inactivated during the plateau phase of the PRL surge. In contrast, TH in the striatum is relatively inactive in the basal state and is not affected by hormonal changes induced by PMSG. We conclude that the peak PRL surge occurs in spite of active dopamine (DA) neurons, suggesting that it is generated by a nondopaminergic mechanism. Decreased TH activity in DA neurons in the SME and PP may prolong the PRL surge during the plateau phase, whereas increased DA activity coincides with the termination of the surge.
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