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Gonzales J, Dharshika C, Mazhar K, Morales-Soto W, McClain JL, Moeser AJ, Nault R, Price TJ, Gulbransen BD. Early life adversity promotes gastrointestinal dysfunction through a sex-dependent phenotypic switch in enteric glia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.31.596805. [PMID: 38895433 PMCID: PMC11185517 DOI: 10.1101/2024.05.31.596805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Irritable bowel syndrome and related disorders of gut-brain interaction (DGBI) are common and exhibit a complex, poorly understood etiology that manifests as abnormal gut motility and pain. Risk factors such as biological sex, stressors during critical periods, and inflammation are thought to influence DGBI vulnerability by reprogramming gut-brain circuits, but the specific cells affected are unclear. Here, we used a model of early life stress to understand cellular mechanisms in the gut that produce DGBIs. Our findings identify enteric glia as a key cellular substrate in which stress and biological sex converge to dictate DGBI susceptibility. Enteric glia exhibit sexual dimorphism in genes and functions related to cellular communication, inflammation, and disease susceptibility. Experiencing early life stress has sex-specific effects on enteric glia that cause a phenotypic switch in male glia toward a phenotype normally observed in females. This phenotypic transformation is followed by physiological changes in the gut, mirroring those observed in DGBI in humans. These effects are mediated, in part, by alterations to glial prostaglandin and endocannabinoid signaling. Together, these data identify enteric glia as a cellular integration site through which DGBI risk factors produce changes in gut physiology and suggest that manipulating glial signaling may represent an attractive target for sex-specific therapeutic strategies in DGBIs.
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2
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Mao X, Shen J. Potential roles of enteric glial cells in Crohn's disease: A critical review. Cell Prolif 2024; 57:e13536. [PMID: 37551711 PMCID: PMC10771111 DOI: 10.1111/cpr.13536] [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: 01/31/2023] [Revised: 07/23/2023] [Accepted: 07/26/2023] [Indexed: 08/09/2023] Open
Abstract
Enteric glial cells in the enteric nervous system are critical for the regulation of gastrointestinal homeostasis. Increasing evidence suggests two-way communication between enteric glial cells and both enteric neurons and immune cells. These interactions may be important in the pathogenesis of Crohn's disease (CD), a chronic relapsing disease characterized by a dysregulated immune response. Structural abnormalities in glial cells have been identified in CD. Furthermore, classical inflammatory pathways associated with CD (e.g., the nuclear factor kappa-B pathway) function in enteric glial cells. However, the specific mechanisms by which enteric glial cells contribute to CD have not been summarized in detail. In this review, we describe the possible roles of enteric glial cells in the pathogenesis of CD, including the roles of glia-immune interactions, neuronal modulation, neural plasticity, and barrier integrity. Additionally, the implications for the development of therapeutic strategies for CD based on enteric glial cell-mediated pathogenic processes are discussed.
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Affiliation(s)
- Xinyi Mao
- Division of Gastroenterology and HepatologyBaoshan Branch, Renji Hospital, School of Medicine, Shanghai Jiao Tong UniversityShanghaiChina
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and HepatologyMinistry of Health, Inflammatory Bowel Disease Research Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive DiseaseShanghaiChina
| | - Jun Shen
- Division of Gastroenterology and HepatologyBaoshan Branch, Renji Hospital, School of Medicine, Shanghai Jiao Tong UniversityShanghaiChina
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and HepatologyMinistry of Health, Inflammatory Bowel Disease Research Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive DiseaseShanghaiChina
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3
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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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4
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Baghdadi MB, Kim TH. The multiple roles of enteric glial cells in intestinal homeostasis and regeneration. Semin Cell Dev Biol 2023:S1084-9521(23)00005-8. [PMID: 36658046 DOI: 10.1016/j.semcdb.2023.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 12/16/2022] [Accepted: 01/06/2023] [Indexed: 01/18/2023]
Abstract
The gastrointestinal tract is innervated by the enteric nervous system (ENS), a complex network of neurons and glial cells, also called the "second brain". Enteric glial cells, one of the major cell types in the ENS, are located throughout the entire gut wall. Accumulating evidence has demonstrated their critical requirement for gut physiology. Notably, recent studies have shown that enteric glial cells control new aspects of gut function such as regulation of intestinal stem cell behavior and immunity. In addition, the emergence of single-cell genomics technologies has revealed enteric glial cell heterogeneity and plasticity. In this review, we discuss established and emerging concepts regarding the roles of mammalian enteric glial cells and their heterogeneity in gut development, homeostasis, and regeneration.
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Affiliation(s)
- Meryem B Baghdadi
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
| | - Tae-Hee Kim
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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5
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Teramoto H, Hirashima N, Tanaka M. A Simple Method for Purified Primary Culture of Enteric Glial Cells from Mouse Small Intestine. Biol Pharm Bull 2022; 45:547-551. [DOI: 10.1248/bpb.b22-00038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Hikaru Teramoto
- Department of Cellular Biophysics, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | - Naohide Hirashima
- Department of Cellular Biophysics, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | - Masahiko Tanaka
- Department of Cellular Biophysics, Graduate School of Pharmaceutical Sciences, Nagoya City University
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6
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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: 122] [Impact Index Per Article: 40.7] [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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7
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Valès S, Bacola G, Biraud M, Touvron M, Bessard A, Geraldo F, Dougherty KA, Lashani S, Bossard C, Flamant M, Duchalais E, Marionneau-Lambot S, Oullier T, Oliver L, Neunlist M, Vallette FM, Van Landeghem L. Tumor cells hijack enteric glia to activate colon cancer stem cells and stimulate tumorigenesis. EBioMedicine 2019; 49:172-188. [PMID: 31662289 PMCID: PMC6945247 DOI: 10.1016/j.ebiom.2019.09.045] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/25/2019] [Accepted: 09/25/2019] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Colon cancer stem cells (CSCs), considered responsible for tumor initiation and cancer relapse, are constantly exposed to regulatory cues emanating from neighboring cells present in the tumor microenvironment. Among these cells are enteric glial cells (EGCs) that are potent regulators of the epithelium functions in a healthy intestine. However, whether EGCs impact CSC-driven tumorigenesis remains unknown. METHODS Impact of human EGC primary cultures or a non-transformed EGC line on CSCs isolated from human primary colon adenocarcinomas or colon cancer cell lines with different p53, MMR system and stemness status was determined using murine xenograft models and 3D co-culture systems. Supernatants of patient-matched human primary colon adenocarcinomas and non-adjacent healthy mucosa were used to mimic tumor versus healthy mucosa secretomes and compare their effects on EGCs. FINDINGS Our data show that EGCs stimulate CSC expansion and ability to give rise to tumors via paracrine signaling. Importantly, only EGCs that were pre-activated by tumor epithelial cell-derived soluble factors increased CSC tumorigenicity. Pharmacological inhibition of PGE2 biosynthesis in EGCs or IL-1 knockdown in tumor epithelial cells prevented EGC acquisition of a pro-tumorigenic phenotype. Inhibition of PGE2 receptor EP4 and EGFR in CSCs inhibited the effects of tumor-activated EGCs. INTERPRETATION Altogether, our results show that EGCs, once activated by the tumor, acquire a pro-tumorigenic phenotype and stimulate CSC-driven tumorigenesis via a PGE2/EP4/EGFR-dependent pathway. FUNDING This work was supported by grants from the French National Cancer Institute, La Ligue contre le Cancer, the 'Région des Pays de la Loire' and the UNC Lineberger Comprehensive Cancer Center.
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Affiliation(s)
- Simon Valès
- Bretagne Loire University, Nantes University, INSERM 1235, IMAD, The Enteric Nervous System in Gut and Brain Disorders, Nantes, France
| | - Gregory Bacola
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Mandy Biraud
- Bretagne Loire University, Nantes University, INSERM 1235, IMAD, The Enteric Nervous System in Gut and Brain Disorders, Nantes, France
| | - Mélissa Touvron
- Bretagne Loire University, Nantes University, INSERM 1235, IMAD, The Enteric Nervous System in Gut and Brain Disorders, Nantes, France,Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Anne Bessard
- Bretagne Loire University, Nantes University, INSERM 1235, IMAD, The Enteric Nervous System in Gut and Brain Disorders, Nantes, France
| | - Fanny Geraldo
- Nantes University, INSERM 1232, CRCINA, Nantes, France
| | - Kelsie A. Dougherty
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Shaian Lashani
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | | | - Mathurin Flamant
- Nantes University Hospital, Nantes, France,Jules Verne Clinic, Nantes, France
| | - Emilie Duchalais
- Bretagne Loire University, Nantes University, INSERM 1235, IMAD, The Enteric Nervous System in Gut and Brain Disorders, Nantes, France,Nantes University Hospital, Nantes, France
| | | | | | - Lisa Oliver
- Nantes University, INSERM 1232, CRCINA, Nantes, France,Nantes University Hospital, Nantes, France
| | - Michel Neunlist
- Bretagne Loire University, Nantes University, INSERM 1235, IMAD, The Enteric Nervous System in Gut and Brain Disorders, Nantes, France,Nantes University Hospital, Nantes, France
| | | | - Laurianne Van Landeghem
- Bretagne Loire University, Nantes University, INSERM 1235, IMAD, The Enteric Nervous System in Gut and Brain Disorders, Nantes, France,Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA,Corresponding author at: North Carolina State University, College of Veterinary Medicine, 1060 William Moore Drive, CB# 8401, Raleigh, NC 27607, USA.
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8
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Delvalle NM, Fried DE, Rivera-Lopez G, Gaudette L, Gulbransen BD. Cholinergic activation of enteric glia is a physiological mechanism that contributes to the regulation of gastrointestinal motility. Am J Physiol Gastrointest Liver Physiol 2018; 315:G473-G483. [PMID: 29927320 PMCID: PMC6230698 DOI: 10.1152/ajpgi.00155.2018] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The reflexive activities of the gastrointestinal tract are regulated, in part, by precise interactions between neurons and glia in the enteric nervous system (ENS). Intraganglionic enteric glia are a unique type of peripheral glia that surround enteric neurons and regulate neuronal function, activity, and survival. Enteric glia express numerous neurotransmitter receptors that allow them to sense neuronal activity, but it is not clear if enteric glia monitor acetylcholine (ACh), the primary excitatory neurotransmitter in the ENS. Here, we tested the hypothesis that enteric glia detect ACh and that glial activation by ACh contributes to the physiological regulation of gut functions. Our results show that myenteric enteric glia express both the M3 and M5 subtypes of muscarinic receptors (MRs) and that muscarine drives intracellular calcium (Ca2+) signaling predominantly through M3R activation. To elucidate the functional effects of activation of glial M3Rs, we used GFAP::hM3Dq mice that express a modified human M3R (hM3Dq) exclusively on glial fibrillary acidic protein (GFAP) positive glia to directly activate glial hM3Dqs using clozapine- N-oxide. Using spatiotemporal mapping analysis, we found that the activation of glial hM3Dq receptors enhances motility reflexes ex vivo. Continuous stimulation of hM3Dq receptors in vivo, drove changes in gastrointestinal motility without affecting neuronal survival in the ENS and glial muscarinic receptor activation did not alter neuron survival in vitro. Our results provide the first evidence that GFAP intraganglionic enteric glia express functional muscarinic receptors and suggest that the activation of glial muscarinic receptors contributes to the physiological regulation of functions. NEW & NOTEWORTHY Enteric glia are emerging as novel regulators of enteric reflex circuits, but little is still known regarding the effects of specific transmitter pathways on glia and the resulting consequences on enteric reflexes. Here, we provide the first evidence that enteric glia monitor acetylcholine in the enteric nervous system and that glial activation by acetylcholine is a physiological mechanism that contributes to the functional regulation of intestinal reflexes.
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Affiliation(s)
| | - David E. Fried
- 2Department of Physiology, Michigan State University, East Lansing, Michigan
| | | | - Luke Gaudette
- 1Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Brian D. Gulbransen
- 1Neuroscience Program, Michigan State University, East Lansing, Michigan,2Department of Physiology, Michigan State University, East Lansing, Michigan
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9
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Pochard C, Coquenlorge S, Freyssinet M, Naveilhan P, Bourreille A, Neunlist M, Rolli-Derkinderen M. The multiple faces of inflammatory enteric glial cells: is Crohn's disease a gliopathy? Am J Physiol Gastrointest Liver Physiol 2018. [PMID: 29517926 DOI: 10.1152/ajpgi.00016.2018] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Gone are the days when enteric glial cells (EGC) were considered merely satellites of enteric neurons. Like their brain counterpart astrocytes, EGC express an impressive number of receptors for neurotransmitters and intercellular messengers, thereby contributing to neuroprotection and to the regulation of neuronal activity. EGC also produce different soluble factors that regulate neighboring cells, among which are intestinal epithelial cells. A better understanding of EGC response to an inflammatory environment, often referred to as enteric glial reactivity, could help define the physiological role of EGC and the importance of this reactivity in maintaining gut functions. In chronic inflammatory disorders of the gut such as Crohn's disease (CD) and ulcerative colitis, EGC exhibit abnormal phenotypes, and their neighboring cells are dysfunctional; however, it remains unclear whether EGC are only passive bystanders or active players in the pathophysiology of both disorders. The aim of the present study is to review the physiological roles and properties of EGC, their response to inflammation, and their role in the regulation of the intestinal epithelial barrier and to discuss the emerging concept of CD as an enteric gliopathy.
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Affiliation(s)
- Camille Pochard
- Inserm, UMR1235 TENS, Nantes , France.,Nantes University , Nantes , France.,Institut des Maladies de l'Appareil Digestif, IMAD, Centre Hospitalier Universitaire de Nantes, Hôpital Hôtel-Dieu, Nantes , France
| | - Sabrina Coquenlorge
- Inserm, UMR1235 TENS, Nantes , France.,Nantes University , Nantes , France.,Institut des Maladies de l'Appareil Digestif, IMAD, Centre Hospitalier Universitaire de Nantes, Hôpital Hôtel-Dieu, Nantes , France
| | - Marie Freyssinet
- Inserm, UMR1235 TENS, Nantes , France.,Nantes University , Nantes , France.,Institut des Maladies de l'Appareil Digestif, IMAD, Centre Hospitalier Universitaire de Nantes, Hôpital Hôtel-Dieu, Nantes , France
| | - Philippe Naveilhan
- Inserm, UMR1235 TENS, Nantes , France.,Nantes University , Nantes , France.,Institut des Maladies de l'Appareil Digestif, IMAD, Centre Hospitalier Universitaire de Nantes, Hôpital Hôtel-Dieu, Nantes , France
| | - Arnaud Bourreille
- Inserm, UMR1235 TENS, Nantes , France.,Nantes University , Nantes , France.,Institut des Maladies de l'Appareil Digestif, IMAD, Centre Hospitalier Universitaire de Nantes, Hôpital Hôtel-Dieu, Nantes , France
| | - Michel Neunlist
- Inserm, UMR1235 TENS, Nantes , France.,Nantes University , Nantes , France.,Institut des Maladies de l'Appareil Digestif, IMAD, Centre Hospitalier Universitaire de Nantes, Hôpital Hôtel-Dieu, Nantes , France
| | - Malvyne Rolli-Derkinderen
- Inserm, UMR1235 TENS, Nantes , France.,Nantes University , Nantes , France.,Institut des Maladies de l'Appareil Digestif, IMAD, Centre Hospitalier Universitaire de Nantes, Hôpital Hôtel-Dieu, Nantes , France
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10
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Fujita M, Yagi T, Okura U, Tanaka J, Hirashima N, Tanaka M. Calcineurin B1 Deficiency in Glial Cells Induces Mucosal Degeneration and Inflammation in Mouse Small Intestine. Biol Pharm Bull 2018; 41:786-796. [DOI: 10.1248/bpb.b18-00041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Maya Fujita
- Department of Cellular Biophysics, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | - Takaki Yagi
- Department of Cellular Biophysics, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | - Umi Okura
- Department of Cellular Biophysics, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | - Jun’ichi Tanaka
- Department of Cellular Biophysics, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | - Naohide Hirashima
- Department of Cellular Biophysics, Graduate School of Pharmaceutical Sciences, Nagoya City University
| | - Masahiko Tanaka
- Department of Cellular Biophysics, Graduate School of Pharmaceutical Sciences, Nagoya City University
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11
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Grubišić V, Verkhratsky A, Zorec R, Parpura V. Enteric glia regulate gut motility in health and disease. Brain Res Bull 2018; 136:109-117. [PMID: 28363846 PMCID: PMC5620110 DOI: 10.1016/j.brainresbull.2017.03.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/20/2017] [Accepted: 03/28/2017] [Indexed: 12/16/2022]
Abstract
The enteric nervous system, often referred to as the second brain, is the largest assembly of neurons and glia outside the central nervous system. The enteric nervous system resides within the wall of the digestive tract and regulates local gut reflexes involved in gastrointestinal motility and fluid transport; these functions can be accomplished in the absence of the extrinsic innervation from the central nervous system. It is neurons and their circuitry within the enteric nervous system that govern the gut reflexes. However, it is becoming clear that enteric glial cells are also actively involved in this process through the bidirectional signaling with neurons and other cells in the gut wall. We synthesize the recently discovered modulatory roles of enteric gliotransmission in gut motility and provide our perspective for future lines of research.
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Affiliation(s)
- Vladimir Grubišić
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA; Neuroscience Program, Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA
| | - Alexei Verkhratsky
- The University of Manchester, Manchester, UK; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology University of Ljubljana, Ljubljana, Slovenia; Celica BIOMEDICAL, Ljubljana, Slovenia
| | - Vladimir Parpura
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
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12
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Smith TK, Koh SD. A model of the enteric neural circuitry underlying the generation of rhythmic motor patterns in the colon: the role of serotonin. Am J Physiol Gastrointest Liver Physiol 2017; 312:G1-G14. [PMID: 27789457 PMCID: PMC5283906 DOI: 10.1152/ajpgi.00337.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 10/19/2016] [Indexed: 01/31/2023]
Abstract
We discuss the role of multiple cell types involved in rhythmic motor patterns in the large intestine that include tonic inhibition of the muscle layers interrupted by rhythmic colonic migrating motor complexes (CMMCs) and secretomotor activity. We propose a model that assumes these motor patterns are dependent on myenteric descending 5-hydroxytryptamine (5-HT, serotonin) interneurons. Asynchronous firing in 5-HT neurons excite inhibitory motor neurons (IMNs) to generate tonic inhibition occurring between CMMCs. IMNs release mainly nitric oxide (NO) to inhibit the muscle, intrinsic primary afferent neurons (IPANs), glial cells, and pacemaker myenteric pacemaker interstitial cells of Cajal (ICC-MY). Mucosal release of 5-HT from enterochromaffin (EC) cells excites the mucosal endings of IPANs that synapse with 5-HT descending interneurons and perhaps ascending interneurons, thereby coupling EC cell 5-HT to myenteric 5-HT neurons, synchronizing their activity. Synchronized 5-HT neurons generate a slow excitatory postsynaptic potential in IPANs via 5-HT7 receptors and excite glial cells and ascending excitatory nerve pathways that are normally inhibited by NO. Excited glial cells release prostaglandins to inhibit IMNs (disinhibition) to allow full excitation of ICC-MY and muscle by excitatory motor neurons (EMNs). EMNs release ACh and tachykinins to excite pacemaker ICC-MY and muscle, leading to the simultaneous contraction of both the longitudinal and circular muscle layers. Myenteric 5-HT neurons also project to the submucous plexus to couple motility with secretion, especially during a CMMC. Glial cells are necessary for switching between different colonic motor behaviors. This model emphasizes the importance of myenteric 5-HT neurons and the likely consequence of their coupling and uncoupling to mucosal 5-HT by IPANs during colonic motor behaviors.
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Affiliation(s)
- Terence Keith Smith
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Sang Don Koh
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
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13
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Coquenlorge S, Van Landeghem L, Jaulin J, Cenac N, Vergnolle N, Duchalais E, Neunlist M, Rolli-Derkinderen M. The arachidonic acid metabolite 11β-ProstaglandinF2α controls intestinal epithelial healing: deficiency in patients with Crohn's disease. Sci Rep 2016; 6:25203. [PMID: 27140063 PMCID: PMC4853710 DOI: 10.1038/srep25203] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 03/15/2016] [Indexed: 02/07/2023] Open
Abstract
In healthy gut enteric glial cells (EGC) are essential to intestinal epithelial barrier (IEB) functions. In Crohn's Disease (CD), both EGC phenotype and IEB functions are altered, but putative involvement of EGC in CD pathogenesis remains unknown and study of human EGC are lacking. EGC isolated from CD and control patients showed similar expression of glial markers and EGC-derived soluble factors (IL6, TGF-β, proEGF, GSH) but CD EGC failed to increase IEB resistance and healing. Lipid profiling showed that CD EGC produced decreased amounts of 15-HETE, 18-HEPE, 15dPGJ2 and 11βPGF2α as compared to healthy EGC. They also had reduced expression of the L-PGDS and AKR1C3 enzymes. Produced by healthy EGC, the 11βPGF2 activated PPARγ receptor of intestinal epithelial cells to induce cell spreading and IEB wound repair. In addition to this novel healing mechanism our data show that CD EGC presented impaired ability to promote IEB functions through defect in L-PGDS-AKR1C3-11βPGF2α dependent pathway.
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Affiliation(s)
- Sabrina Coquenlorge
- INSERM, UMR913, Nantes, F-44093, France
- Université Nantes, Nantes, F-44093, France
- Institut des Maladies de l’Appareil Digestif, CHU Nantes, Hôpital Hôtel-Dieu, Nantes, F-44093, France
- Centre de Recherche en Nutrition Humaine, Nantes, F-44093, France
| | - Laurianne Van Landeghem
- INSERM, UMR913, Nantes, F-44093, France
- Université Nantes, Nantes, F-44093, France
- Institut des Maladies de l’Appareil Digestif, CHU Nantes, Hôpital Hôtel-Dieu, Nantes, F-44093, France
- Centre de Recherche en Nutrition Humaine, Nantes, F-44093, France
| | - Julie Jaulin
- INSERM, UMR913, Nantes, F-44093, France
- Université Nantes, Nantes, F-44093, France
- Institut des Maladies de l’Appareil Digestif, CHU Nantes, Hôpital Hôtel-Dieu, Nantes, F-44093, France
- Centre de Recherche en Nutrition Humaine, Nantes, F-44093, France
| | - Nicolas Cenac
- Centre de Pathophysiologie, CHU Purpan, Toulouse, France
- INSERM UMR-1043 CNRS UMR-5282, Toulouse, France
| | - Nathalie Vergnolle
- Centre de Pathophysiologie, CHU Purpan, Toulouse, France
- INSERM UMR-1043 CNRS UMR-5282, Toulouse, France
| | - Emilie Duchalais
- INSERM, UMR913, Nantes, F-44093, France
- Université Nantes, Nantes, F-44093, France
- Institut des Maladies de l’Appareil Digestif, CHU Nantes, Hôpital Hôtel-Dieu, Nantes, F-44093, France
- Centre de Recherche en Nutrition Humaine, Nantes, F-44093, France
| | - Michel Neunlist
- INSERM, UMR913, Nantes, F-44093, France
- Université Nantes, Nantes, F-44093, France
- Institut des Maladies de l’Appareil Digestif, CHU Nantes, Hôpital Hôtel-Dieu, Nantes, F-44093, France
- Centre de Recherche en Nutrition Humaine, Nantes, F-44093, France
| | - Malvyne Rolli-Derkinderen
- INSERM, UMR913, Nantes, F-44093, France
- Université Nantes, Nantes, F-44093, France
- Institut des Maladies de l’Appareil Digestif, CHU Nantes, Hôpital Hôtel-Dieu, Nantes, F-44093, France
- Centre de Recherche en Nutrition Humaine, Nantes, F-44093, France
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14
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Pochard C, Coquenlorge S, Jaulin J, Cenac N, Vergnolle N, Meurette G, Freyssinet M, Neunlist M, Rolli-Derkinderen M. Defects in 15-HETE Production and Control of Epithelial Permeability by Human Enteric Glial Cells From Patients With Crohn's Disease. Gastroenterology 2016; 150:168-80. [PMID: 26433161 DOI: 10.1053/j.gastro.2015.09.038] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 08/25/2015] [Accepted: 09/16/2015] [Indexed: 12/18/2022]
Abstract
BACKGROUND & AIMS Enteric glial cells (EGCs) produce soluble mediators that regulate homeostasis and permeability of the intestinal epithelial barrier (IEB). We investigated the profile of polyunsaturated fatty acid (PUFA) metabolites produced by EGCs from rats and from patients with Crohn's disease (CD), compared with controls, along with the ability of one of these metabolites, 15-hydroxyeicosatetraenoic acid (15-HETE), to regulate the permeability of the IEB. METHODS We isolated EGCs from male Sprague-Dawley rats, intestinal resections of 6 patients with CD, and uninflamed healthy areas of intestinal tissue from 6 patients who underwent surgery for colorectal cancer (controls). EGC-conditioned media was analyzed by high-sensitivity liquid-chromatography tandem mass spectrometry to determine PUFA signatures. We used immunostaining to identify 15-HETE-producing enzymes in EGCs and tissues. The effects of human EGCs and 15-HETE on permeability and transepithelial electrical resistance of the IEB were measured using Caco-2 cells; effects on signal transduction proteins were measured with immunoblots. Levels of proteins were reduced in Caco-2 cells using short-hairpin RNAs or proteins were inhibited pharmacologically. Rats were given intraperitoneal injections of 15-HETE or an inhibitor of 15-lipoxygenase (the enzyme that produces 15-HETE); colons were collected and permeability was measured. RESULTS EGCs expressed 15-lipoxygenase-2 and produced high levels of 15-HETE, which increased IEB resistance and reduced IEB permeability. 15-HETE production was reduced in EGCs from patients with CD compared with controls. EGCs from patients with CD were unable to reduce the permeability of the IEB; the addition of 15-HETE restored permeability to levels of control tissues. Inhibiting 15-HETE production in rats increased the permeability of the IEB in colon tissues. We found that 15-HETE regulates IEB permeability by inhibiting an adenosine monophosphate-activated protein kinase and increasing expression of zonula occludens-1. CONCLUSIONS Enteric glial cells from patients with CD have reduced production of 15-HETE, which controls IEB permeability by inhibiting adenosine monophosphate-activated protein kinase and increasing expression of zonula occludens-1.
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Affiliation(s)
- Camille Pochard
- INSERM, UMR913, Nantes, France; Nantes University, Nantes, France; Institut des Maladies de l'Appareil Digestif, IMAD, CHU Nantes, Hopital Hôtel-Dieu, Nantes, France; Centre de Recherche en Nutrition Humaine, Nantes, France
| | - Sabrina Coquenlorge
- INSERM, UMR913, Nantes, France; Nantes University, Nantes, France; Institut des Maladies de l'Appareil Digestif, IMAD, CHU Nantes, Hopital Hôtel-Dieu, Nantes, France; Centre de Recherche en Nutrition Humaine, Nantes, France
| | - Julie Jaulin
- INSERM, UMR913, Nantes, France; Nantes University, Nantes, France; Institut des Maladies de l'Appareil Digestif, IMAD, CHU Nantes, Hopital Hôtel-Dieu, Nantes, France; Centre de Recherche en Nutrition Humaine, Nantes, France
| | | | | | - Guillaume Meurette
- INSERM, UMR913, Nantes, France; Nantes University, Nantes, France; Institut des Maladies de l'Appareil Digestif, IMAD, CHU Nantes, Hopital Hôtel-Dieu, Nantes, France; Centre de Recherche en Nutrition Humaine, Nantes, France
| | - Marie Freyssinet
- INSERM, UMR913, Nantes, France; Institut des Maladies de l'Appareil Digestif, IMAD, CHU Nantes, Hopital Hôtel-Dieu, Nantes, France; Centre de Recherche en Nutrition Humaine, Nantes, France
| | - Michel Neunlist
- INSERM, UMR913, Nantes, France; Nantes University, Nantes, France; Institut des Maladies de l'Appareil Digestif, IMAD, CHU Nantes, Hopital Hôtel-Dieu, Nantes, France; Centre de Recherche en Nutrition Humaine, Nantes, France.
| | - Malvyne Rolli-Derkinderen
- INSERM, UMR913, Nantes, France; Nantes University, Nantes, France; Institut des Maladies de l'Appareil Digestif, IMAD, CHU Nantes, Hopital Hôtel-Dieu, Nantes, France; Centre de Recherche en Nutrition Humaine, Nantes, France.
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15
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The effect of bradykinin on the electrical activity of rat myenteric neurons. Eur J Pharmacol 2014; 738:158-69. [PMID: 24886885 DOI: 10.1016/j.ejphar.2014.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 04/01/2014] [Accepted: 05/10/2014] [Indexed: 01/21/2023]
Abstract
Bradykinin is a mediator involved in inflammatory processes in the gut. Here we investigated the effect of bradykinin on the electrical activity of rat myenteric neurons, the key players for regulation of gastrointestinal motility. Bradykinin (2 × 10(-8)mol/l) induced a biphasic increase in frequency of action potentials measured with microelectrode arrays. This increase was mirrored by a biphasic increase in cytosolic Ca(2+) concentration ([Ca(2+)]i), which was observed in about 40% of the myenteric neurons. The bradykinin B1 receptor agonist des-arg(9)-bradykinin as well as the bradykinin B2 receptor agonist hyp(3)-bradykinin induced a similar effect on [Ca(2+)]i. Immunocytochemical stainings confirmed the expression of both receptor types by myenteric ganglionic cells. Real time PCR showed that the inducible B1 receptor was upregulated during cell culture. The inhibition of cyclooxygenases with piroxicam reduced the effect of bradykinin on the electrical activity of myenteric neurons. The suppression of the glial growth on microelectrode arrays did not affect the bradykinin-induced change in frequency of action potentials. This suggests that prostaglandins, which probably mediate the effect of bradykinin, are not exclusively released from glial cells. The bradykinin-induced increase in [Ca(2+)]i was dependent on the presence of extracellular Ca(2+) and was inhibited by Co(2+), Cd(2+), and Ni(2+), blockers of voltage-dependent Ca(2+) channels, indicating a stimulation of the influx of extracellular Ca(2+) by the kinin. Consequently, bradykinin induces a Ca(2+) influx in myenteric neurons via Ca(2+) channels in the plasma membrane.
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16
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Avemary J, Diener M. Bradykinin-induced depolarisation and Ca2+ influx through voltage-gated Ca2+ channels in rat submucosal neurons. Eur J Pharmacol 2010; 635:87-95. [DOI: 10.1016/j.ejphar.2010.03.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 02/12/2010] [Accepted: 03/03/2010] [Indexed: 11/25/2022]
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17
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Avemary J, Diener M. Effects of bradykinin B2 receptor stimulation at submucosal ganglia from rat distal colon. Eur J Pharmacol 2010; 627:295-303. [DOI: 10.1016/j.ejphar.2009.10.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 09/21/2009] [Accepted: 10/14/2009] [Indexed: 10/20/2022]
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18
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Kim D, Cho SH, Kim JS, Jo SH, Lee SJ, Kim KT, Choi SY. Human astrocytic bradykinin B(2) receptor modulates zymosan-induced cytokine expression in 1321N1 cells. Peptides 2010; 31:101-7. [PMID: 19854233 DOI: 10.1016/j.peptides.2009.10.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Revised: 10/14/2009] [Accepted: 10/14/2009] [Indexed: 11/17/2022]
Abstract
Bradykinin is an important modulator of the neurons and glial cells of the nervous system. Bradykinin secreted from neurons affects astrocytic functions such as neurovascular coupling and astrocytic cytokine production. In human astrocytes, however, the detailed mechanism of bradykinin-mediated modulation of astrocytic functions has not yet been fully elucidated. Here, we report the functional expression of the bradykinin B(2) receptor and its modulation of zymosan-induced cytokine expression in human astrocytoma 1321N1 cells. Bradykinin increased cytosolic [Ca(2+)] in a concentration-dependent manner, whereas [des-Arg(10)] kallidin (an agonist of the B(1) receptor) did not have this effect. Bradykinin also triggered intracellular InsP(3) production. Pretreating the cells with HOE140 (icatibant acetate, a B(2) receptor antagonist) inhibited the bradykinin-induced increase in cytosolic [Ca(2+)] and InsP(3) production. In contrast, [des-Arg(10)]HOE140 (a B(1) receptor antagonist) did not show any inhibitory effect. Bradykinin increased the zymosan-induced expression of TNF-alpha, and interleukin 1beta (IL-1beta) but did not affect the expression of interleukin 6 (IL-6) or interleukin 10 (IL-10). Interestingly, a cyclooxygenase-2 specific inhibitor blocked the bradykinin-induced effect. In contrast to the result in human glioma cells, bradykinin inhibits the zymosan-induced expression of TNF-alpha and IL-1beta in rat astrocytes, which shows a species-dependent manner. These data suggest that bradykinin B(2) receptors are expressed in human astrocytoma cells and that they modulate the expression pattern of inflammatory cytokines.
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Affiliation(s)
- Donghoon Kim
- Department of Physiology and Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea
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19
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Murakami M, Ohta T, Ito S. Lipopolysaccharides enhance the action of bradykinin in enteric neurons via secretion of interleukin-1beta from enteric glial cells. J Neurosci Res 2009; 87:2095-104. [PMID: 19235895 DOI: 10.1002/jnr.22036] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Functional changes of the enteric nervous system have been observed under inflammatory states of inflammatory bowel disease increasing the endotoxin level. The aim of the present study was to determine the effect of lipopolysaccharides (LPS) on myenteric neuron-glia interaction in vitro. We examined the increase of the intracellular Ca(2+) concentration ([Ca(2+)](i)) and the release of interleukin-1beta (IL-1beta) or prostaglandin E(2) (PGE(2)) and COX-2 expression in myenteric plexus cells from the rat intestine induced by LPS. LPS potentiated BK-induced [Ca(2+)](i) increases in both myenteric neurons and enteric glial cells, which were suppressed by a B1R antagonist. Only in enteric glial cells, a B1R agonist increased [Ca(2+)](i). The effects of LPS were blocked by pretreatment with an interleukin-1 receptor antagonist or by reducing the density of enteric glial cells in culture. LPS prompted the release of IL-1beta from enteric glial cells. The augmenting effects of IL-1beta on the BK-induced neural [Ca(2+)](i) increase and PGE(2) release from enteric glial cells were abolished by a phospholipase A(2) (PLA(2)) inhibitor and a COX inhibitor, and partly suppressed by a COX-2 inhibitor. IL-1beta up-regulated the COX-2 expression in enteric glial cells. LPS promotes IL-1beta secretion from enteric glial cells, resulting in augmentation of the neural response to BK through PGE(2) release via glial PLA(2) and COX-2. The alteration of the regulatory effect of glial cells may be the cause of the changes in neural function in the enteric nervous system in inflammatory bowel disease.
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Affiliation(s)
- Matsuka Murakami
- Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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20
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Su J, Cui M, Tang Y, Zhou H, Liu L, Dong Q. Blockade of bradykinin B2 receptor more effectively reduces postischemic blood-brain barrier disruption and cytokines release than B1 receptor inhibition. Biochem Biophys Res Commun 2009; 388:205-11. [PMID: 19647718 DOI: 10.1016/j.bbrc.2009.07.135] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Accepted: 07/27/2009] [Indexed: 01/04/2023]
Abstract
Blood-brain barrier disruption and brain edema are detrimental in ischemic stroke. The kallikrein-kinin system appears to play an important role in the regulation of vascular permeability and is invoked in edema formation. The effects of kinins are mediated by bradykinin receptors B1R and B2R. However, little is known about the exact roles of bradykinin receptors in the early stage of cerebral ischemia. In this study, we demonstrated that ischemia upregulated the level of B1R and B2R at 24h after reperfusion by immunofluorescence assays, mainly expressed in astrocytes and neurons, respectively, in the ischemic penumbra. Moreover, B2R inhibition more effectively reduced neurological severity scores, blood-brain barrier permeability and cytokines release than B1R inhibition did. Additionally, B2R inhibition also significantly suppressed B1R protein level. Therefore, blockade of B2R may be a more effective strategy for the treatment of ischemic brain injury than B1R inhibition within 24h after reperfusion.
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Affiliation(s)
- Jingjing Su
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, People's Republic of China
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21
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Gu Q, Wiggers ME, Gleich GJ, Lee LY. Sensitization of isolated rat vagal pulmonary sensory neurons by eosinophil-derived cationic proteins. Am J Physiol Lung Cell Mol Physiol 2008; 294:L544-52. [DOI: 10.1152/ajplung.00271.2007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It has been shown that airway exposure to eosinophil-derived cationic proteins stimulated vagal pulmonary C fibers and markedly potentiated their responses to lung inflation in anesthetized rats (Lee LY, Gu Q, Gleich GJ, J Appl Physiol 91: 1318–1326, 2001). However, whether the effects resulted from a direct action of these proteins on the sensory nerves was not known. The present study was therefore carried out to determine the effects of these proteins on isolated rat vagal pulmonary sensory neurons. Our results obtained from perforated whole cell patch-clamp recordings showed that pretreatment with eosinophil major basic protein (MBP; 2 μM, 60 s) significantly increased the capsaicin-evoked inward current in these neurons; this effect peaked ∼10 min after MBP and lasted for >60 min; in current-clamp mode, MBP substantially increased the number of action potentials evoked by both capsaicin and electrical stimulation. Pretreatment with MBP did not significantly alter the input resistance of these sensory neurons. In addition, the sensitizing effect of MBP was completely abolished when its cationic charge was neutralized by mixing with a polyanion, such as low-molecular-weight heparin or poly-l-glutamic or poly-l-aspartic acid, before its delivery to the neurons. Moreover, a similar sensitizing effect was also generated by other eosinophil granule-derived proteins (e.g., eosinophil peroxidase). These results demonstrate a direct, charge-dependent, and long-lasting sensitizing effect of cationic proteins on pulmonary sensory neurons, which may contribute to the airway hyperresponsiveness associated with airway infiltration of eosinophils under pathophysiological conditions.
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Interleukin-1β enhances the action of bradykinin in rat myenteric neurons through up-regulation of glial B1 receptor expression. Neuroscience 2008; 151:222-31. [DOI: 10.1016/j.neuroscience.2007.09.065] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Revised: 09/18/2007] [Accepted: 09/28/2007] [Indexed: 01/24/2023]
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23
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Bassotti G, Villanacci V, Antonelli E, Morelli A, Salerni B. Enteric glial cells: new players in gastrointestinal motility? J Transl Med 2007; 87:628-32. [PMID: 17483847 DOI: 10.1038/labinvest.3700564] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The enteric glial cells, in addition to being support structures for the enteric nervous system, have many other additional roles, such as modulators for the homeostasis of enteric neurons, cells involved in enteric neurotransmission and antigen-presenting cells. Moreover, in the last years, data have been accumulating that demonstrate a possible active role of these cells in the pathophysiology of gastrointestinal motor activity. Thus, as also shown by recent evidence in both experimental animal models, and in some human diseases, alterations of enteric glial cells might have some role in the development of intestinal motor abnormalities.
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Affiliation(s)
- Gabrio Bassotti
- Gastroenterology and Hepatology Section, Department of Clinical and Experimental Medicine, University of Perugia, Perugia, Italy.
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24
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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: 135] [Impact Index Per Article: 3.9] [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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