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Tough IR, Lund ML, Patel BA, Schwartz TW, Cox HM. Paracrine relationship between incretin hormones and endogenous 5-hydroxytryptamine in the small and large intestine. Neurogastroenterol Motil 2023; 35:e14589. [PMID: 37010838 PMCID: PMC10909488 DOI: 10.1111/nmo.14589] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 02/13/2023] [Accepted: 03/21/2023] [Indexed: 04/04/2023]
Abstract
BACKGROUND Enterochromaffin (EC) cell-derived 5-hydroxytryptamine (5-HT) is a mediator of toxin-induced reflexes, initiating emesis via vagal and central 5-HT3 receptors. The amine is also involved in gastrointestinal (GI) reflexes that are prosecretory and promotile, and recently 5-HT's roles in chemosensation in the distal bowel have been described. We set out to establish the efficacy of 5-HT signaling, local 5-HT levels and pharmacology in discrete regions of the mouse small and large intestine. We also investigated the inter-relationships between incretin hormones, glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP) and endogenous 5-HT in mucosal and motility assays. METHODS Adult mouse GI mucosae were mounted in Ussing chambers and area-specific studies were performed to establish the 5-HT3 and 5-HT4 pharmacology, the sidedness of responses, and the inter-relationships between incretins and endogenous 5-HT. Natural fecal pellet transit in vitro and full-length GI transit in vivo were also measured. KEY RESULTS We observed the greatest level of tonic and exogenous 5-HT-induced ion transport and highest levels of 5-HT in ascending colon mucosa. Here both 5-HT3 and 5-HT4 receptors were involved but elsewhere in the GI tract epithelial basolateral 5-HT4 receptors mediate 5-HT's prosecretory effect. Exendin-4 and GIP induced 5-HT release in the ascending colon, while L cell-derived PYY also contributed to GIP mucosal effects in the descending colon. Both peptides slowed colonic transit. CONCLUSIONS & INFERENCES We provide functional evidence for paracrine interplay between 5-HT, GLP-1 and GIP, particularly in the colonic mucosal region. Basolateral epithelial 5-HT4 receptors mediated both 5-HT and incretin mucosal responses in healthy colon.
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Affiliation(s)
- Iain R. Tough
- Wolfson Centre for Age‐Related Diseases, Institute of Psychology, Psychiatry and NeuroscienceKing's College LondonHodgkin Building, Guy's CampusLondonSE1 1ULUK
| | - Mari L. Lund
- The Novo Nordisk Foundation Centre for Basic Metabolic Research, Section for Metabolic Receptology and EnteroendocrinologyUniversity of CopenhagenCopenhagenDK‐2200Denmark
- Present address:
Chr. Hansen A/S, Human Health ResearchHoersholmDK‐2970Denmark
| | - Bhavik A. Patel
- Centre for Stress and Age‐Related Diseases, School of Applied SciencesUniversity of BrightonBrightonUK
| | - Thue W. Schwartz
- The Novo Nordisk Foundation Centre for Basic Metabolic Research, Section for Metabolic Receptology and EnteroendocrinologyUniversity of CopenhagenCopenhagenDK‐2200Denmark
| | - Helen M. Cox
- Wolfson Centre for Age‐Related Diseases, Institute of Psychology, Psychiatry and NeuroscienceKing's College LondonHodgkin Building, Guy's CampusLondonSE1 1ULUK
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2
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Sarker R, Lin R, Singh V, Donowitz M, Tse CM. SLC26A3 (DRA) is stimulated in a synergistic, intracellular Ca 2+-dependent manner by cAMP and ATP in intestinal epithelial cells. Am J Physiol Cell Physiol 2023; 324:C1263-C1273. [PMID: 37154494 PMCID: PMC10243534 DOI: 10.1152/ajpcell.00523.2022] [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: 11/17/2022] [Revised: 04/24/2023] [Accepted: 04/24/2023] [Indexed: 05/10/2023]
Abstract
In polarized intestinal epithelial cells, downregulated in adenoma (DRA) is an apical Cl-/[Formula: see text] exchanger that is part of neutral NaCl absorption under baseline conditions, but in cyclic adenosine monophosphate (cAMP)-driven diarrheas, it is stimulated and contributes to increased anion secretion. To further understand the regulation of DRA in conditions mimicking some diarrheal diseases, Caco-2/BBE cells were exposed to forskolin (FSK) and adenosine 5'-triphosphate (ATP). FSK and ATP stimulated DRA in a concentration-dependent manner, with ATP acting via P2Y1 receptors. FSK at 1 µM and ATP at 0.25 µM had minimal to no effect on DRA given individually; however, together, they stimulated DRA to levels seen with maximum concentrations of FSK and ATP alone. In Caco-2/BBE cells expressing the Ca2+ indicator GCaMP6s, ATP increased intracellular Ca2+ (Ca2+i) in a concentration-dependent manner, whereas FSK (1 µM), which by itself did not significantly alter Ca2+i, followed by 0.25 µM ATP produced a large increase in Ca2+ that was approximately equal to the elevation caused by 1 µM ATP. 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester) (BAPTA-AM) pretreatment prevented the ATP and FSK/ATP synergistically increased the DRA activity and the increase in Ca2+i caused by FSK/ATP. FSK/ATP synergistic stimulation of DRA was similarly observed in human colonoids. In Caco-2/BBE cells, subthreshold concentrations of FSK (cAMP) and ATP (Ca2+) synergistically increased Ca2+i and stimulated DRA activity with both being blocked by BAPTA-AM pretreatment. Diarrheal diseases, such as bile acid diarrhea, in which both cAMP and Ca2+ are elevated, are likely to be associated with stimulated DRA activity contributing to increased anion secretion, whereas separation of DRA from Na+/H+ exchanger isoform-3 (NHE3) contributes to reduced NaCl absorption.NEW & NOTEWORTHY The BB Cl-/[Formula: see text] exchanger DRA takes part in both neutral NaCl absorption and stimulated anion secretion. Using intestinal cell line, Caco-2/BBE high concentrations of cAMP and Ca2+ individually stimulated DRA activity, whereas low concentrations, which had no/minimal effect, synergistically stimulated DRA activity that required a synergistic increase in intracellular Ca2+. This study increases understanding of diarrheal diseases, such as bile salt diarrhea, in which both cAMP and elevated Ca2+ are involved.
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Affiliation(s)
- Rafiquel Sarker
- Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Ruxian Lin
- Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Varsha Singh
- Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Mark Donowitz
- Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Chung-Ming Tse
- Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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3
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Gebert JT, Scribano F, Engevik KA, Perry JL, Hyser JM. Gastrointestinal organoids in the study of viral infections. Am J Physiol Gastrointest Liver Physiol 2023; 324:G51-G59. [PMID: 36414538 PMCID: PMC9799139 DOI: 10.1152/ajpgi.00152.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 11/04/2022] [Accepted: 11/14/2022] [Indexed: 11/24/2022]
Abstract
Viruses are among the most prevalent enteric pathogens. Although virologists historically relied on cell lines and animal models, human intestinal organoids (HIOs) continue to grow in popularity. HIOs are nontransformed, stem cell-derived, ex vivo cell cultures that maintain the cell type diversity of the intestinal epithelium. They offer higher throughput than standard animal models while more accurately mimicking the native tissue of infection than transformed cell lines. Here, we review recent literature that highlights virological advances facilitated by HIOs. We discuss the variations and limitations of HIOs, how HIOs have allowed for the cultivation of previously uncultivatable viruses, and how they have offered insight into tropism, entry, replication kinetics, and host-pathogen interactions. In each case, we discuss exemplary viruses and archetypal studies. We discuss how the speed and flexibility of HIO-based studies contributed to our knowledge of SARS-CoV-2 and antiviral therapeutics. Finally, we discuss the current limitations of HIOs and future directions to overcome these.
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Affiliation(s)
- J Thomas Gebert
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas
| | - Francesca Scribano
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas
| | - Kristen A Engevik
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas
| | - Jacob L Perry
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas
| | - Joseph M Hyser
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas
- Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, Texas
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4
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Liao XX, Wu XY, Zhou YL, Li JJ, Wen YL, Zhou JJ. Gut microbiome metabolites as key actors in atherosclerosis co-depression disease. Front Microbiol 2022; 13:988643. [PMID: 36439791 PMCID: PMC9686300 DOI: 10.3389/fmicb.2022.988643] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 10/24/2022] [Indexed: 02/26/2024] Open
Abstract
Cardiovascular diseases, mainly characterized by atherosclerosis (AS), and depression have a high comorbidity rate. However, previous studies have been conducted under a single disease, and there is a lack of studies in comorbid states to explore the commonalities in the pathogenesis of both diseases. Modern high-throughput technologies have made it clear that the gut microbiome can affect the development of the host's own disorders and have shown that their metabolites are crucial to the pathophysiology of AS and depression. The aim of this review is to summarize the current important findings on the role of gut microbiome metabolites such as pathogen-associated molecular patterns, bile acids, tryptophan metabolites, short-chain fatty acids, and trimethylamine N -oxide in depression and AS disease, with the aim of identifying potential biological targets for the early diagnosis and treatment of AS co-depression disorders.
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Affiliation(s)
- Xing-Xing Liao
- School of Rehabilitation Medicine, Gannan Medical University, Ganzhou, China
| | - Xiao-Yun Wu
- School of Basic Medicine, Gannan Medical University, Ganzhou, China
| | - Yu-Long Zhou
- School of Rehabilitation Medicine, Gannan Medical University, Ganzhou, China
| | - Jia-Jun Li
- School of Rehabilitation Medicine, Gannan Medical University, Ganzhou, China
| | - You-Liang Wen
- School of Rehabilitation Medicine, Gannan Medical University, Ganzhou, China
| | - Jun-Jie Zhou
- School of Rehabilitation Medicine, Gannan Medical University, Ganzhou, China
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou, China
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5
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Choudhury MI, Benson MA, Sun SX. Trans-epithelial fluid flow and mechanics of epithelial morphogenesis. Semin Cell Dev Biol 2022; 131:146-159. [PMID: 35659163 DOI: 10.1016/j.semcdb.2022.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/22/2022] [Accepted: 05/23/2022] [Indexed: 12/14/2022]
Abstract
Active fluid transport across epithelial monolayers is emerging as a major driving force of tissue morphogenesis in a variety of healthy and diseased systems, as well as during embryonic development. Cells use directional transport of ions and osmotic gradients to drive fluid flow across the cell surface, in the process also building up fluid pressure. The basic physics of this process is described by the osmotic engine model, which also underlies actin-independent cell migration. Recently, the trans-epithelial fluid flux and the hydraulic pressure gradient have been explicitly measured for a variety of cellular and tissue model systems across various species. For the kidney, it was shown that tubular epithelial cells behave as active mechanical fluid pumps: the trans-epithelial fluid flux depends on the hydraulic pressure difference across the epithelial layer. When a stall pressure is reached, the fluid flux vanishes. Hydraulic forces generated from active fluid pumping are important in tissue morphogenesis and homeostasis, and could also underlie multiple morphogenic events seen in other developmental contexts. In this review, we highlight findings that examined the role of trans-epithelial fluid flux and hydraulic pressure gradient in driving tissue-scale morphogenesis. We also review organ pathophysiology due to impaired fluid pumping and the loss of hydraulic pressure sensing at the cellular scale. Finally, we draw an analogy between cellular fluidic pumps and a connected network of water pumps in a city. The dynamics of fluid transport in an active and adaptive network is determined globally at the systemic level, and transport in such a network is best when each pump is operating at its optimal efficiency.
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Affiliation(s)
- Mohammad Ikbal Choudhury
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States; Institute of NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, United States; Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, United States
| | - Morgan A Benson
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, United States; Institute of NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, United States
| | - Sean X Sun
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States; Institute of NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, United States; Center for Cell Dynamics, Johns Hopkins University, Baltimore, MD 21218, United States.
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6
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Keely SJ, Urso A, Ilyaskin AV, Korbmacher C, Bunnett NW, Poole DP, Carbone SE. Contributions of bile acids to gastrointestinal physiology as receptor agonists and modifiers of ion channels. Am J Physiol Gastrointest Liver Physiol 2022; 322:G201-G222. [PMID: 34755536 PMCID: PMC8782647 DOI: 10.1152/ajpgi.00125.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 10/28/2021] [Accepted: 11/08/2021] [Indexed: 02/03/2023]
Abstract
Bile acids (BAs) are known to be important regulators of intestinal motility and epithelial fluid and electrolyte transport. Over the past two decades, significant advances in identifying and characterizing the receptors, transporters, and ion channels targeted by BAs have led to exciting new insights into the molecular mechanisms involved in these processes. Our appreciation of BAs, their receptors, and BA-modulated ion channels as potential targets for the development of new approaches to treat intestinal motility and transport disorders is increasing. In the current review, we aim to summarize recent advances in our knowledge of the different BA receptors and BA-modulated ion channels present in the gastrointestinal system. We discuss how they regulate motility and epithelial transport, their roles in pathogenesis, and their therapeutic potential in a range of gastrointestinal diseases.
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Affiliation(s)
- Stephen J Keely
- Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin, Ireland
| | - Andreacarola Urso
- Department of Surgery, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York
- Department of Pharmacology, Columbia University, New York, New York
| | - Alexandr V Ilyaskin
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander University Erlangen-Nürnberg, Bavaria, Germany
| | - Christoph Korbmacher
- Institute of Cellular and Molecular Physiology, Friedrich-Alexander University Erlangen-Nürnberg, Bavaria, Germany
| | - Nigel W Bunnett
- Department of Molecular Pathobiology, Neuroscience Institute, New York University, New York, New York
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University, New York, New York
| | - Daniel P Poole
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- Australian Research Council, Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Simona E Carbone
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- Australian Research Council, Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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7
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Li ZS, Hung LY, Margolis KG, Ambron RT, Sung YJ, Gershon MD. The α isoform of cGMP-dependent protein kinase 1 (PKG1α) is expressed and functionally important in intrinsic primary afferent neurons of the guinea pig enteric nervous system. Neurogastroenterol Motil 2021; 33:e14100. [PMID: 33655600 PMCID: PMC8681866 DOI: 10.1111/nmo.14100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 01/18/2021] [Accepted: 01/26/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Intrinsic primary afferent neurons (IPANs) enable the gut to manifest reflexes in the absence of CNS input. PKG1α is selectively expressed in a subset of neurons in dorsal root ganglia (DRG) and has been linked to nociception and long-term hyperexcitability. METHODS We used immunoblotting, immunocytochemistry, and in vitro assays of IPAN-dependent enteric functions to test hypotheses that subsets of primary neurons of the ENS and DRG share a reliance on PKG1α expression. KEY RESULTS PKG1α immunoreactivity was demonstrated in immunoblots from isolated myenteric ganglia. PKG1α, but not PKG1β, immunoreactivity, was coincident with that of neuronal markers (HuC/D; β3-tubulin) in both enteric plexuses. PKG1α immunoreactivity also co-localized with the immunoreactivities of the IPAN markers, calbindin (100%; myenteric plexus) and cytoplasmic NeuN (98 ± 1% submucosal plexus). CGRP-immunoreactive DRG neurons, identified as visceral afferents by retrograde transport, were PKG1α-immunoreactive. We used intraluminal cholera toxin to determine whether PKG1α was necessary to enable stimulation of the mucosa to activate Fos in enteric neurons. Tetrodotoxin (1.0 µM), low Ca2+ /high Mg2+ media, and the PKG inhibitor, N46 (100 µM), all inhibited Fos activation in myenteric neurons. N46 also concentration dependently inhibited peristaltic reflexes in isolated preparations of distal colon (IC50 = 83.3 ± 1.3 µM). CONCLUSIONS & INFERENCES These data suggest that PKG1α is present and functionally important in IPANs and visceral afferent nociceptive neurons.
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Affiliation(s)
- Zhi S. Li
- Departments of Pathology & Cell Biology, Columbia University, New York, NY, USA
| | - Lin Y. Hung
- Departments of Pediatrics, Columbia University, New York, NY, USA
| | - Kara G. Margolis
- Departments of Pediatrics, Columbia University, New York, NY, USA
| | - Richard T. Ambron
- Departments of Pathology & Cell Biology, Columbia University, New York, NY, USA
| | - Ying J. Sung
- Departments of Basic Science, The Commonwealth Medical College, Scranton, PA, USA
| | - Michael D. Gershon
- Departments of Pathology & Cell Biology, Columbia University, New York, NY, USA
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8
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Pergolizzi S, Rizzo G, Favaloro A, Alesci A, Pallio S, Melita G, Cutroneo G, Lauriano ER. Expression of VAChT and 5-HT in Ulcerative colitis dendritic cells. Acta Histochem 2021; 123:151715. [PMID: 33940317 DOI: 10.1016/j.acthis.2021.151715] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/21/2021] [Accepted: 04/21/2021] [Indexed: 02/07/2023]
Abstract
Ulcerative colitis is a chronic inflammatory condition of the gastrointestinal tract that can affect people of worldwide. In contrast with Crohn's disease, that can relate the entire thickness of the bowel wall, the inflammation of ulcerative colitis is limited to the colonic mucosa. Immune cells including activated T cells, plasma cells, mast cells, macrophages, and dendritic cells (DCs) trigger the inflammation. Furthermore, dendritic cells are antigen presenting cells involved in maintaining intestinal immune homeostasis. It has been described an increment of number in DCs colonic mucosa of patients with ulcerative colitis. The immune cells such as antigen-presenting cells can act as autocrine or paracrine modulators. Recent studies showed that dendritic cells synthetized and released classical neurotransmitters as glutamate, dopamine, acetylcholine, and serotonin. Paraformaldehyde-fixed intestinal tissues, obtained from the stricture sites of ten patients with ulcerative colitis were analyzed by immunostaining for Langerin/CD207, serotonin and vesicular acetylcholine transporter. As controls, unaffected (normal) portions of five patients were also investigated. Aim of this study was to characterize for the first time the human gut dendritic cells of ulcerative colitis patients, with Langerin/CD207 that is a c-type lectin expressed by different types of DCs and to colocalize in the same cells the expression of serotonin and vesicular acetylcholine transporter, showing the link between dendritic cells, gut enterochromaffin cells or autonomic nerves in immune activation and generation of intestinal inflammation.
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Bistoletti M, Bosi A, Banfi D, Giaroni C, Baj A. The microbiota-gut-brain axis: Focus on the fundamental communication pathways. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 176:43-110. [PMID: 33814115 DOI: 10.1016/bs.pmbts.2020.08.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Michela Bistoletti
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Annalisa Bosi
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Davide Banfi
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Cristina Giaroni
- Department of Medicine and Surgery, University of Insubria, Varese, Italy.
| | - Andreina Baj
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
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10
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Bosi A, Banfi D, Bistoletti M, Giaroni C, Baj A. Tryptophan Metabolites Along the Microbiota-Gut-Brain Axis: An Interkingdom Communication System Influencing the Gut in Health and Disease. Int J Tryptophan Res 2020; 13:1178646920928984. [PMID: 32577079 PMCID: PMC7290275 DOI: 10.1177/1178646920928984] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 05/02/2020] [Indexed: 12/12/2022] Open
Abstract
The ‘microbiota-gut-brain axis’ plays a fundamental role in maintaining host homeostasis, and different immune, hormonal, and neuronal signals participate to this interkingdom communication system between eukaryota and prokaryota. The essential aminoacid tryptophan, as a precursor of several molecules acting at the interface between the host and the microbiota, is fundamental in the modulation of this bidirectional communication axis. In the gut, tryptophan undergoes 3 major metabolic pathways, the 5-HT, kynurenine, and AhR ligand pathways, which may be directly or indirectly controlled by the saprophytic flora. The importance of tryptophan metabolites in the modulation of the gastrointestinal tract is suggested by several preclinical and clinical studies; however, a thorough revision of the available literature has not been accomplished yet. Thus, this review attempts to cover the major aspects on the role of tryptophan metabolites in host-microbiota cross-talk underlaying regulation of gut functions in health conditions and during disease states, with particular attention to 2 major gastrointestinal diseases, such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), both characterized by psychiatric disorders. Research in this area opens the possibility to target tryptophan metabolism to ameliorate the knowledge on the pathogenesis of both diseases, as well as to discover new therapeutic strategies based either on conventional pharmacological approaches or on the use of pre- and probiotics to manipulate the microbial flora.
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Affiliation(s)
- Annalisa Bosi
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Davide Banfi
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Michela Bistoletti
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Cristina Giaroni
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Andreina Baj
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
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11
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Yu Y, Villalobos-Hernandez EC, Pradhananga S, Baker CC, Keating C, Grundy D, Lomax AE, Reed DE. Deoxycholic acid activates colonic afferent nerves via 5-HT 3 receptor-dependent and -independent mechanisms. Am J Physiol Gastrointest Liver Physiol 2019; 317:G275-G284. [PMID: 31216174 DOI: 10.1152/ajpgi.00016.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Increased bile acids in the colon can evoke increased epithelial secretion resulting in diarrhea, but little is known about whether colonic bile acids contribute to abdominal pain. This study aimed to investigate the mechanisms underlying activation of colonic extrinsic afferent nerves and their neuronal cell bodies by a major secondary bile acid, deoxycholic acid (DCA). All experiments were performed on male C57BL/6 mice. Afferent sensitivity was evaluated using in vitro extracellular recordings from mesenteric nerves in the proximal colon (innervated by vagal and spinal afferents) and distal colon (spinal afferents only). Neuronal excitability of cultured dorsal root ganglion (DRG) and nodose ganglion (NG) neurons was examined with perforated patch clamp. Colonic 5-HT release was assessed using ELISA, and 5-HT immunoreactive enterochromaffin (EC) cells were quantified. Intraluminal DCA increased afferent nerve firing rate concentration dependently in both proximal and distal colon. This DCA-elicited increase was significantly inhibited by a 5-HT3 antagonist in the proximal colon but not in the distal colon, which may be in part due to lower 5-HT immunoreactive EC cell density and lower 5-HT levels in the distal colon following DCA stimulation. DCA increased the excitability of DRG neurons, whereas it decreased the excitability of NG neurons. DCA potentiated mechanosensitivity of high-threshold spinal afferents independent of 5-HT release. Together, this study suggests that DCA can excite colonic afferents via direct and indirect mechanisms but the predominant mechanism may differ between vagal and spinal afferents. Furthermore, DCA increased mechanosensitivity of high-threshold spinal afferents and may be a mechanism of visceral hypersensitivity.NEW & NOTEWORTHY Deoxycholic acid (DCA) directly excites spinal afferents and, to a lesser extent, indirectly via mucosal 5-HT release. DCA potentiates mechanosensitivity of high-threshold spinal afferents independent of 5-HT release. DCA increases vagal afferent firing in proximal colon via 5-HT release but directly inhibits the excitability of their cell bodies.
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Affiliation(s)
- Yang Yu
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | | | - Sabindra Pradhananga
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Corey C Baker
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Christopher Keating
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - David Grundy
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Alan E Lomax
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - David E Reed
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
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12
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Hegyi P, Maléth J, Walters JR, Hofmann AF, Keely SJ. Guts and Gall: Bile Acids in Regulation of Intestinal Epithelial Function in Health and Disease. Physiol Rev 2019; 98:1983-2023. [PMID: 30067158 DOI: 10.1152/physrev.00054.2017] [Citation(s) in RCA: 164] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Epithelial cells line the entire surface of the gastrointestinal tract and its accessory organs where they primarily function in transporting digestive enzymes, nutrients, electrolytes, and fluid to and from the luminal contents. At the same time, epithelial cells are responsible for forming a physical and biochemical barrier that prevents the entry into the body of harmful agents, such as bacteria and their toxins. Dysregulation of epithelial transport and barrier function is associated with the pathogenesis of a number of conditions throughout the intestine, such as inflammatory bowel disease, chronic diarrhea, pancreatitis, reflux esophagitis, and cancer. Driven by discovery of specific receptors on intestinal epithelial cells, new insights into mechanisms that control their synthesis and enterohepatic circulation, and a growing appreciation of their roles as bioactive bacterial metabolites, bile acids are currently receiving a great deal of interest as critical regulators of epithelial function in health and disease. This review aims to summarize recent advances in this field and to highlight how bile acids are now emerging as exciting new targets for disease intervention.
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Affiliation(s)
- Peter Hegyi
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Joszef Maléth
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Julian R Walters
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Alan F Hofmann
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
| | - Stephen J Keely
- Momentum Translational Gastroenterology Research Group, Hungarian Academy of Sciences-University of Szeged , Szeged , Hungary ; Institute for Translational Medicine, Medical School, University of Pécs , Pécs , Hungary ; Momentum Epithelial Cell Signalling and Secretion Research Group and First Department of Medicine, University of Szeged , Szeged , Hungary ; Division of Digestive Diseases, Department of Gastroenterology, Hammersmith Hospital, Imperial College London , London , United Kingdom ; Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, California ; and Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital , Dublin , Ireland
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13
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Malhi H, Camilleri M. Modulating bile acid pathways and TGR5 receptors for treating liver and GI diseases. Curr Opin Pharmacol 2017; 37:80-86. [PMID: 29102744 DOI: 10.1016/j.coph.2017.09.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 12/27/2022]
Abstract
Bile acids are central signals in enterohepatic communication and also integrate microbiota-derived signals into this signaling axis. Discovery of the tissue distribution and signaling pathways activated by the natural receptors for bile acids, farnesoid X receptor and G protein-coupled bile acid receptor 1 (GPBAR1) also known as TGR5, and bile acid transporters has led to the development of therapeutic agents that target these molecules. Obeticholic acid, a selective FXR agonist, and NGM282, a non-mitogenic FGF-19 analog, are two of the agents in this pipeline. Obeticholic acid has been approved by regulatory agencies for use in patients with primary biliary cholangitis.
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Affiliation(s)
- Harmeet Malhi
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), and Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), and Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN, USA.
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14
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Gross Margolis K, Vittorio J, Talavera M, Gluck K, Li Z, Iuga A, Stevanovic K, Saurman V, Israelyan N, Welch MG, Gershon MD. Enteric serotonin and oxytocin: endogenous regulation of severity in a murine model of necrotizing enterocolitis. Am J Physiol Gastrointest Liver Physiol 2017; 313:G386-G398. [PMID: 28774871 PMCID: PMC5792212 DOI: 10.1152/ajpgi.00215.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 07/28/2017] [Accepted: 07/28/2017] [Indexed: 01/31/2023]
Abstract
Necrotizing enterocolitis (NEC), a gastrointestinal inflammatory disease of unknown etiology that may also affect the liver, causes a great deal of morbidity and mortality in premature infants. We tested the hypothesis that signaling molecules, which are endogenous to the bowel, regulate the severity of intestinal and hepatic damage in an established murine NEC model. Specifically, we postulated that mucosal serotonin (5-HT), which is proinflammatory, would exacerbate experimental NEC and that oxytocin (OT), which is present in enteric neurons and is anti-inflammatory, would oppose it. Genetic deletion of the 5-HT transporter (SERT), which increases and prolongs effects of 5-HT, was found to increase the severity of systemic manifestations, intestinal inflammation, and associated hepatotoxicity of experimental NEC. In contrast, genetic deletion of tryptophan hydroxylase 1 (TPH1), which is responsible for 5-HT biosynthesis in enterochromaffin (EC) cells of the intestinal mucosa, and TPH inhibition with LP-920540 both decrease the severity of experimental NEC in the small intestine and liver. These observations suggest that 5-HT from EC cells helps to drive the inflammatory damage to the gut and liver that occurs in the murine NEC model. Administration of OT decreased, while the OT receptor antagonist atosiban exacerbated, the intestinal inflammation of experimental NEC. Data from the current investigation are consistent with the tested hypotheses-that the enteric signaling molecules, 5-HT (positively) and OT (negatively) regulate severity of inflammation in a mouse model of NEC. Moreover, we suggest that mucosally restricted inhibition of 5-HT biosynthesis and/or administration of OT may be useful in the treatment of NEC.NEW & NOTEWORTHY Serotonin (5-HT) and oxytocin reciprocally regulate the severity of intestinal inflammation and hepatotoxicity in a murine model of necrotizing enterocolitis (NEC). Selective depletion of mucosal 5-HT through genetic deletion or inhibition of tryptophan hydroxylase-1 ameliorates, while deletion of the 5-HT uptake transporter, which increases 5-HT availability, exacerbates the severity of NEC. In contrast, oxytocin reduces, while the oxytocin receptor antagonist atosiban enhances, NEC severity. Peripheral tryptophan hydroxylase inhibition may be useful in treatment of NEC.
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Affiliation(s)
- Kara Gross Margolis
- Department of Pediatrics, Morgan Stanley Children's Hospital, Columbia University Medical Center, New York, New York; .,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York; and
| | - Jennifer Vittorio
- 1Department of Pediatrics, Morgan Stanley Children’s Hospital, Columbia University Medical Center, New York, New York; ,2Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York; and
| | - Maria Talavera
- 1Department of Pediatrics, Morgan Stanley Children’s Hospital, Columbia University Medical Center, New York, New York; ,2Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York; and
| | - Karen Gluck
- 1Department of Pediatrics, Morgan Stanley Children’s Hospital, Columbia University Medical Center, New York, New York; ,2Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York; and
| | - Zhishan Li
- 1Department of Pediatrics, Morgan Stanley Children’s Hospital, Columbia University Medical Center, New York, New York; ,2Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York; and
| | - Alina Iuga
- 2Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York; and
| | - Korey Stevanovic
- 1Department of Pediatrics, Morgan Stanley Children’s Hospital, Columbia University Medical Center, New York, New York; ,2Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York; and
| | - Virginia Saurman
- 1Department of Pediatrics, Morgan Stanley Children’s Hospital, Columbia University Medical Center, New York, New York; ,2Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York; and
| | - Narek Israelyan
- 1Department of Pediatrics, Morgan Stanley Children’s Hospital, Columbia University Medical Center, New York, New York; ,2Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York; and
| | - Martha G. Welch
- 1Department of Pediatrics, Morgan Stanley Children’s Hospital, Columbia University Medical Center, New York, New York; ,2Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York; and ,3Department of Psychiatry, Columbia University Medical Center, New York, New York
| | - Michael D. Gershon
- 2Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York; and
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15
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Bayer SB, Gearry RB, Drummond LN. Putative mechanisms of kiwifruit on maintenance of normal gastrointestinal function. Crit Rev Food Sci Nutr 2017; 58:2432-2452. [PMID: 28557573 DOI: 10.1080/10408398.2017.1327841] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Kiwifruits are recognized as providing relief from constipation and symptoms of constipation-predominant irritable bowel syndrome (IBS-C). However, the underlying mechanisms, specifically in regards to gastrointestinal transit time and motility, are still not completely understood. This review provides an overview on the physiological and pathophysiological processes underlying constipation and IBS-C, the composition of kiwifruit, and recent advances in the research of kiwifruit and abdominal comfort. In addition, gaps in the research are highlighted and scientific studies of other foods with known effects on the gastrointestinal tract are consulted to find likely mechanisms of action. While the effects of kiwifruit fiber are well documented, observed increases in gastrointestinal motility caused by kiwifruit are not fully characterized. There are a number of identified mechanisms that may be activated by kiwifruit compounds, such as the induction of motility via protease-activated signaling, modulation of microflora, changes in colonic methane status, bile flux, or mediation of inflammatory processes.
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Affiliation(s)
- Simone Birgit Bayer
- a Department of Pathology , Center for Free Radical Research, University of Otago , 2 Riccarton Avenue, PO Box 4345, Christchurch , New Zealand
| | - Richard Blair Gearry
- b Department of Medicine , University of Otago , 2 Riccarton Avenue, PO Box 4345, Christchurch , New Zealand
| | - Lynley Ngaio Drummond
- c Drummond Food Science Advisory Ltd. , 1137 Drain Road, Killinchy RD 2, Leeston , New Zealand
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16
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Ge X, Zhao W, Ding C, Tian H, Xu L, Wang H, Ni L, Jiang J, Gong J, Zhu W, Zhu M, Li N. Potential role of fecal microbiota from patients with slow transit constipation in the regulation of gastrointestinal motility. Sci Rep 2017; 7:441. [PMID: 28348415 PMCID: PMC5428802 DOI: 10.1038/s41598-017-00612-y] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/06/2017] [Indexed: 12/13/2022] Open
Abstract
The gut microbiota is involved in various physiological functions, and disturbances in the host-microbiome have been proven to contribute to the dysfunction of gut; however, whether microbiota participates in the pathogenesis of constipation remains unclear. In this study, we extracted and analyzed microbiota in feces from constipated donors who had undergone effective therapy with fecal microbiota transplantation, transplanted microbiota into pseudo-germ-free mice, and measured gut motility. These mice presented with lower pellet frequency and water percentage, smaller pellet size, delayed gastrointestinal transit time, and weaker spontaneous contractions of colonic smooth muscle. To determine the mechanism underlying delayed gut motility, microbial metabolites were measured. Short chain fatty acids and secondary bile acids were decreased in mice receiving microbiota from constipated donors. Moreover, the compositional changes of gut microbiota in constipated patients were identified, including the operational taxonomic unit, and the species richness and α diversity were much greater than those in healthy volunteers. These findings suggest that alterations of the microbiome might affect gut motility via altered microbial-derived metabolites in the development of constipation, and the restoration of disturbed microbiota might improve the clinical phenotype. This study indicates that regulating the intestinal environment may be a novel therapy strategy for constipation.
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Affiliation(s)
- Xiaolong Ge
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Wei Zhao
- Center of Reproductive Medicine, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Chao Ding
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Hongliang Tian
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Lizhi Xu
- Department of Medical Genetics, and Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210002, China
| | - Hongkan Wang
- First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310000, China
| | - Ling Ni
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Jun Jiang
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China
| | - Jianfeng Gong
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China.
| | - Weiming Zhu
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China.
| | - Minsheng Zhu
- Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, 210002, China
| | - Ning Li
- Department of General Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, China.
- Shanghai Tenth People's Hospital, Tenth People's Hospital of Tongji University, Shanghai, 200072, China.
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17
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Camilleri M, Sellin JH, Barrett KE. Pathophysiology, Evaluation, and Management of Chronic Watery Diarrhea. Gastroenterology 2017; 152:515-532.e2. [PMID: 27773805 PMCID: PMC5285476 DOI: 10.1053/j.gastro.2016.10.014] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/21/2016] [Accepted: 10/11/2016] [Indexed: 02/08/2023]
Abstract
Chronic watery diarrhea poses a diagnostic and therapeutic challenge and is often a disabling condition for patients. Although acute diarrhea is likely to be caused by infection, the causes of chronic diarrhea (>4 weeks in duration) are more elusive. We review the pathophysiology, diagnosis, and treatment of chronic diarrhea. Drawing on recent insights into the molecular mechanisms of intestinal epithelial transport and barrier function, we discuss how diarrhea can result from a decrease in luminal solute absorption, an increase in secretion, or both, as well as derangements in barrier properties. We also describe the various extraepithelial factors that activate diarrheal mechanisms. Finally, clinical evaluation and tests used in the assessment of patients presenting with chronic diarrhea are reviewed, and an algorithm guiding therapeutic decisions and pharmacotherapy is presented.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota.
| | - Joseph H. Sellin
- Division of Gastroenterology, Department of Medicine, Baylor College of Medicine, Houston, TX
| | - Kim E. Barrett
- Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, CA
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18
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Camilleri M, Ford AC. Irritable Bowel Syndrome: Pathophysiology and Current Therapeutic Approaches. Handb Exp Pharmacol 2017; 239:75-113. [PMID: 27995391 DOI: 10.1007/164_2016_102] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Irritable bowel syndrome (IBS) is a prevalent condition affecting 10-20% of adults in most countries; IBS results in significant morbidity and health care costs. IBS is a disorder of the brain-gut axis, and recent insights into the pathophysiological mechanisms include altered bile acid metabolism, neurohormonal regulation, immune dysfunction, alterations in the epithelial barrier, and secretory properties of the gut. There remains a significant unmet need for effective treatments, particularly for the pain component of IBS, although the introduction of drugs directed at secretion, motility, and a nonabsorbable antibiotic provides an option for the bowel dysfunction in IBS.
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Affiliation(s)
- Michael Camilleri
- Department of Medicine, Pharmacology, and Physiology, Division of Gastroenterology, Mayo Clinic College of Medicine, Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), 200 First Street S.W, Rochester, MN, 55905, USA.
| | - Alexander C Ford
- Department of Gastroenterology and Honorary Consultant Gastroenterologist, Leeds Institute of Biomedical and Clinical Sciences, University of Leeds and Leeds Gastroenterology Institute, Leeds Teaching Hospitals Trust, Leeds, UK
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19
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Yde J, Keely S, Wu Q, Borg JF, Lajczak N, O'Dwyer A, Dalsgaard P, Fenton RA, Moeller HB. Characterization of AQPs in Mouse, Rat, and Human Colon and Their Selective Regulation by Bile Acids. Front Nutr 2016; 3:46. [PMID: 27777930 PMCID: PMC5056181 DOI: 10.3389/fnut.2016.00046] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 09/26/2016] [Indexed: 12/12/2022] Open
Abstract
In normal individuals, the epithelium of the colon absorbs 1.5–2 l of water a day to generate dehydrated feces. However, in the condition of bile acid malabsorption (BAM), an excess of bile acids in the colon results in diarrhea. Several studies have attempted to address the mechanisms contributing to BAM induced by various bile acids. However, none have addressed a potential dysregulation of aquaporin (AQP) water channels, which are responsible for the majority of transcellular water transport in epithelial cells, as a contributing factor to the onset of diarrhea and the pathogenesis of BAM. In this study, we aimed to systematically analyze the expression of AQPs in colonic epithelia from rat, mouse, and human and determine whether their expression is altered in a rat model of BAM. Mass spectrometry-based proteomics, RT-PCR, and western blotting identified various AQPs in isolated colonic epithelial cells from rats (AQP1, 3, 4, 7, 8) and mice (AQP1, 4, 8). Several AQPs were also detected in human colon (AQP1, 3, 4, 7–9). Immunohistochemistry localized AQP1 to the apical plasma membrane of epithelial cells in the bottom of the crypts, whereas AQP3 (rat, human) and AQP4 (mice, human) were localized predominantly in the basolateral plasma membrane. AQP8 was localized intracellularly and at the apical plasma membrane of epithelial cells. Rats fed sodium cholate for 72 h had significantly increased fecal water content, suggesting development of BAM-associated diarrhea. Colonic epithelial cells isolated from this model had significantly altered levels of AQP3, 7, and 8, suggesting that these AQPs may be involved in the pathogenesis of bile acid-induced diarrhea.
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Affiliation(s)
- Jonathan Yde
- Department of Biomedicine, InterPrET Center, Aarhus University , Aarhus , Denmark
| | - Stephen Keely
- RCSI Education and Research Centre, Royal College of Surgeons in Ireland, Beaumont Hospital , Dublin , Ireland
| | - Qi Wu
- Department of Biomedicine, InterPrET Center, Aarhus University , Aarhus , Denmark
| | - Johan F Borg
- Department of Biomedicine, InterPrET Center, Aarhus University , Aarhus , Denmark
| | - Natalia Lajczak
- RCSI Education and Research Centre, Royal College of Surgeons in Ireland, Beaumont Hospital , Dublin , Ireland
| | - Aoife O'Dwyer
- RCSI Education and Research Centre, Royal College of Surgeons in Ireland, Beaumont Hospital , Dublin , Ireland
| | | | - Robert A Fenton
- Department of Biomedicine, InterPrET Center, Aarhus University , Aarhus , Denmark
| | - Hanne B Moeller
- Department of Biomedicine, InterPrET Center, Aarhus University , Aarhus , Denmark
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20
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Camilleri M, Gores GJ. Therapeutic targeting of bile acids. Am J Physiol Gastrointest Liver Physiol 2015; 309:G209-15. [PMID: 26138466 PMCID: PMC4537926 DOI: 10.1152/ajpgi.00121.2015] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 06/30/2015] [Indexed: 01/31/2023]
Abstract
The first objectives of this article are to review the structure, chemistry, and physiology of bile acids and the types of bile acid malabsorption observed in clinical practice. The second major theme addresses the classical or known properties of bile acids, such as the role of bile acid sequestration in the treatment of hyperlipidemia; the use of ursodeoxycholic acid in therapeutics, from traditional oriental medicine to being, until recently, the drug of choice in cholestatic liver diseases; and the potential for normalizing diverse bowel dysfunctions in irritable bowel syndrome, either by sequestering intraluminal bile acids for diarrhea or by delivering more bile acids to the colon to relieve constipation. The final objective addresses novel concepts and therapeutic opportunities such as the interaction of bile acids and the microbiome to control colonic infections, as in Clostridium difficile-associated colitis, and bile acid targeting of the farnesoid X receptor and G protein-coupled bile acid receptor 1 with consequent effects on energy expenditure, fat metabolism, and glycemic control.
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Affiliation(s)
- Michael Camilleri
- Division of Gastroenterology and Hepatology, Department of Medicine, College of Medicine, Mayo Clinic, Rochester, Minnesota
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21
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Camilleri M. Intestinal secretory mechanisms in irritable bowel syndrome-diarrhea. Clin Gastroenterol Hepatol 2015; 13:1051-7; quiz e61-2. [PMID: 25041862 PMCID: PMC4297594 DOI: 10.1016/j.cgh.2014.07.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 07/01/2014] [Accepted: 07/07/2014] [Indexed: 02/07/2023]
Abstract
Although diarrhea is the predominant bowel dysfunction in as many as one-third of patients with irritable bowel syndrome (IBS), it is unclear whether there is a specific disorder of intestinal fluid or electrolyte secretion in IBS. Diarrhea is generally considered a result of accelerated colonic transit in patients with IBS. Although a primary secretory diathesis has not been well-documented in patients with IBS with diarrhea (IBS-D), several mechanisms that could potentially contribute to intestinal secretion have been reported. Some of these mechanisms also influence motor and secretory dysfunctions that contribute to the pathophysiology of IBS-D. We review the evidence supporting secretion in IBS-D caused by peptides and amines produced by enteroendocrine cells or submucosal neurons, enterocyte secretory processes, and intraluminal factors (bile acids and short-chain fatty acids). Understanding these mechanisms and developing clinical methods for their identification could improve management of patients with IBS-D.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota.
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22
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Welch MG, Margolis KG, Li Z, Gershon MD. Oxytocin regulates gastrointestinal motility, inflammation, macromolecular permeability, and mucosal maintenance in mice. Am J Physiol Gastrointest Liver Physiol 2014; 307:G848-62. [PMID: 25147234 PMCID: PMC4200316 DOI: 10.1152/ajpgi.00176.2014] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 08/18/2014] [Indexed: 01/31/2023]
Abstract
Enteric neurons express oxytocin (OT); moreover, enteric neurons and enterocytes express developmentally regulated OT receptors (OTRs). Although OT (with secretin) opposes intestinal inflammation, physiological roles played by enteric OT/OTR signaling have not previously been determined. We tested hypotheses that OT/OTR signaling contributes to enteric nervous system (ENS)-related gastrointestinal (GI) physiology. GI functions and OT effects were compared in OTR-knockout (OTRKO) and wild-type (WT) mice. Stool mass and water content were greater in OTRKO mice than in WT. GI transit time in OTRKO animals was faster than in WT; OT inhibited in vitro generation of ENS-dependent colonic migrating motor complexes in WT but not in OTRKO mice. Myenteric neurons were hyperplastic in OTRKO animals, and mucosal exposure to cholera toxin (CTX) in vitro activated Fos in more myenteric neurons in OTRKO than WT than in WT mice; OT inhibited the CTX response in WT but not in OTRKO mice. Villi and crypts were shorter in OTRKO than in WT mice, and transit-amplifying cell proliferation in OTRKO crypts was deficient. Macromolecular intestinal permeability in OTRKO was greater than WT mice, and experimental colitis was more severe in OTRKO mice; moreover, OT protected WT animals from colitis. Observations suggest that OT/OTR signaling acts as a brake on intestinal motility, decreases mucosal activation of enteric neurons, and promotes enteric neuronal development and/or survival. It also regulates proliferation of crypt cells and mucosal permeability; moreover OT/OTR signaling is protective against inflammation. Oxytocinergic signaling thus appears to play an important role in multiple GI functions that are subject to neuronal regulation.
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Affiliation(s)
- Martha G Welch
- Department of Psychiatry, Pediatrics, and Pathology and Cell Biology, Columbia University, College of Physicians and Surgeons, New York, New York
| | - Kara G Margolis
- Department of Psychiatry, Pediatrics, and Pathology and Cell Biology, Columbia University, College of Physicians and Surgeons, New York, New York
| | - Zhishan Li
- Department of Psychiatry, Pediatrics, and Pathology and Cell Biology, Columbia University, College of Physicians and Surgeons, New York, New York
| | - Michael D Gershon
- Department of Psychiatry, Pediatrics, and Pathology and Cell Biology, Columbia University, College of Physicians and Surgeons, New York, New York
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23
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Forsgård RA, Korpela R, Stenman LK, Osterlund P, Holma R. Deoxycholic acid induced changes in electrophysiological parameters and macromolecular permeability in murine small intestine with and without functional enteric nervous system plexuses. Neurogastroenterol Motil 2014; 26:1179-87. [PMID: 24954839 DOI: 10.1111/nmo.12383] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 05/28/2014] [Indexed: 12/19/2022]
Abstract
BACKGROUND We have previously shown in mice that the fecal proportion and concentration of the hydrophobic bile acid deoxycholic acid (DCA) is elevated with high-fat feeding and that these changes are able to disrupt the intestinal barrier function. The aim of this study was to investigate whether these changes are mediated by the enteric nervous system (ENS). METHODS The function of the ENS in the small intestinal tissues of mice was compromised by two different methods: by removing the seromuscular layer and by incubating the intact tissues with tetrodotoxin (TTX), a neural conduction blocker, before DCA treatment. Tissues with or without functional plexuses were mounted into a Ussing chamber system and treated with 3 mM DCA for 20 min. After DCA treatment, the intestinal permeability to fluorescein was assessed. Short-circuit current (Isc ) and transepithelial resistance (TER) were recorded throughout the experiment. KEY RESULTS DCA increased intestinal fluorescein permeability only in tissues where the seromuscular layer was removed. In tissues with intact seromuscular layer, DCA induced a significant increase in TER, which was attenuated by blocking of the neural function by TTX. CONCLUSIONS & INFERENCES The results of this study suggest that the DCA-induced increase observed in fluorescein permeability is not mediated through neural pathways, but more due to a direct effect on the epithelium. However, as TTX was able to attenuate the DCA-induced increase in TER, it can be speculated that DCA is also able to elicit responses through neural pathways.
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Affiliation(s)
- R A Forsgård
- Institute of Biomedicine, Pharmacology, Medical Nutrition Physiology, University of Helsinki, Helsinki, Finland
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Watanabe H, Saito R, Nakano T, Takahashi H, Takahashi Y, Sumiyoshi K, Sato K, Chen X, Okada N, Iwasaki S, Harjanti DW, Sekiguchi N, Sano H, Kitazawa H, Rose MT, Ohwada S, Watanabe K, Aso H. Effect of peripheral 5-HT on glucose and lipid metabolism in wether sheep. PLoS One 2014; 9:e88058. [PMID: 24505376 PMCID: PMC3913723 DOI: 10.1371/journal.pone.0088058] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 01/06/2014] [Indexed: 11/18/2022] Open
Abstract
In mice, peripheral 5-HT induces an increase in the plasma concentrations of glucose, insulin and bile acids, and a decrease in plasma triglyceride, NEFA and cholesterol concentrations. However, given the unique characteristics of the metabolism of ruminants relative to monogastric animals, the physiological role of peripheral 5-HT on glucose and lipid metabolism in sheep remains to be established. Therefore, in this study, we investigated the effect of 5-HT on the circulating concentrations of metabolites and insulin using five 5-HT receptor (5HTR) antagonists in sheep. After fasting for 24 h, sheep were intravenously injected with 5-HT, following which-, plasma glucose, insulin, triglyceride and NEFA concentrations were significantly elevated. In contrast, 5-HT did not affect the plasma cholesterol concentration, and it induced a decrease in bile acid concentrations. Increases in plasma glucose and insulin concentrations induced by 5-HT were attenuated by pre-treatment with Methysergide, a 5HTR 1, 2 and 7 antagonist. Additionally, decreased plasma bile acid concentrations induced by 5-HT were blocked by pre-treatment with Ketanserin, a 5HTR 2A antagonist. However, none of the 5HTR antagonists inhibited the increase in plasma triglyceride and NEFA levels induced by 5-HT. On the other hand, mRNA expressions of 5HTR1D and 1E were observed in the liver, pancreas and skeletal muscle. These results suggest that there are a number of differences in the physiological functions of peripheral 5-HT with respect to lipid metabolism between mice and sheep, though its effect on glucose metabolism appears to be similar between these species.
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Affiliation(s)
- Hitoshi Watanabe
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Ryo Saito
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Tatsuya Nakano
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Hideyuki Takahashi
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Yu Takahashi
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Keisuke Sumiyoshi
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Katsuyoshi Sato
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Xiangning Chen
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Natsumi Okada
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Shunsuke Iwasaki
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Dian W Harjanti
- Department of Animal Sciences, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Natsumi Sekiguchi
- Department of Animal Sciences, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Hiroaki Sano
- Department of Animal Sciences, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Haruki Kitazawa
- Laboratory of Food and Biomolecular Science, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Michael T Rose
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Cardiganshire, United Kingdom
| | - Shyuichi Ohwada
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Kouichi Watanabe
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Hisashi Aso
- Cellar Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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Abstract
Bile acids (BA) are actively reabsorbed in the terminal ileum by the apical Na(+)-dependent bile salt transporter. This review addresses the epidemiology, pathophysiology, diagnosis and treatment of BA diarrhea (BAD). BAD is typically caused by ileal resection or disease; 25-33% of patients with chronic functional diarrhea or irritable bowel syndrome-diarrhea (IBS-D) have BAD, possibly from deficiency in the ileal hormone, FGF-19, which normally provides feedback inhibition of BA synthesis. Diagnosis of BAD is typically based on reduced BA retention of radiolabeled BA ((75)SeHCAT), increased BA synthesis (serum C4) or increased fecal BA loss. In clinical practice, diagnosis is often based on response to BA sequestrants (e.g., cholestyramine or colesevelam). Diagnostic tests for BA malabsorption (BAM) need to be used more extensively in clinical practice. In the future, farnesoid X receptor agonists that stimulate ileal production of FGF-19 may be alternative treatments of BAD.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Mayo Clinic, 200 First St. S.W., Charlton Bldg., Rm. 8-110, Rochester, MN 55905, USA
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26
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Abstract
Serotonin (5-HT) has been recognized for decades as an important signalling molecule in the gut, but it is still revealing its secrets. Novel gastrointestinal functions of 5-HT continue to be discovered, as well as distant actions of gut-derived 5-HT, and we are learning how 5-HT signalling is altered in gastrointestinal disorders. Conventional functions of 5-HT involving intrinsic reflexes include stimulation of propulsive and segmentation motility patterns, epithelial secretion and vasodilation. Activation of extrinsic vagal and spinal afferent fibres results in slowed gastric emptying, pancreatic secretion, satiation, pain and discomfort, as well as nausea and vomiting. Within the gut, 5-HT also exerts nonconventional actions such as promoting inflammation and serving as a trophic factor to promote the development and maintenance of neurons and interstitial cells of Cajal. Platelet 5-HT, originating in the gut, promotes haemostasis, influences bone development and serves many other functions. 5-HT3 receptor antagonists and 5-HT4 receptor agonists have been used to treat functional disorders with diarrhoea or constipation, respectively, and the synthetic enzyme tryptophan hydroxylase has also been targeted. Emerging evidence suggests that exploiting epithelial targets with nonabsorbable serotonergic agents could provide safe and effective therapies. We provide an overview of these serotonergic actions and treatment strategies.
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Klinck JS, Wood CM. Gastro-intestinal transport of calcium and cadmium in fresh water and seawater acclimated trout (Oncorhynchus mykiss). Comp Biochem Physiol C Toxicol Pharmacol 2013. [PMID: 23201586 DOI: 10.1016/j.cbpc.2012.11.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Transport of calcium (Ca) and cadmium (Cd) was examined along the gastro-intestinal tract (GIT) of freshwater and seawater Oncorhynchus mykiss irideus (FWT and SWTies respectively) using in vitro and in vivo experiments. Based on known physiological differences between FWT and SWT which aid in regulating ion levels and osmolarity, we hypothesized that SWT would have lower rates of Ca uptake. Also, we predicted that Cd rates would also be lower because Cd is known to share a common transport mechanism with Ca. Kinetics of Ca and Cd transport were determined using mucosal salines of varying concentrations [1, 10, 30, 60, and 100 (mmolL(-1) for Ca, μmolL(-1) for Cd)]. Linear and saturating relationships were found for Ca for FWT and SWT, but overall SWT had lower rates. Linear and/or saturating relationships were also found for Cd uptake, but rates varied little between fish types. Elevated Ca had no inhibitory effect on Cd transport, and Ca channel blockers nifedipine and verapamil had little effect on Ca or Cd uptake. However, lanthanum reduced Ca transport into some compartments. A 21 day in vivo feeding experiment was also performed where FWT and SWT were exposed to control diets or Cd-spiked diets (552 μg Cd g(-1) food). Whole body Cd uptake between fish types was similar, but the majority of Cd in SWT remained in the posterior intestine tissue, while FWT transported more Cd through their gut wall. Overall it appears that large differences in Ca and Cd uptake between FWT and SWT exist, with SWT generally having lower rates.
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Affiliation(s)
- Joel S Klinck
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), College of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
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Duodenal calcium transporter mRNA expression in stressed male rats treated with diazepam, fluoxetine, reboxetine, or venlafaxine. Mol Cell Biochem 2012; 369:87-94. [DOI: 10.1007/s11010-012-1371-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Accepted: 06/20/2012] [Indexed: 01/22/2023]
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Abstract
Ohman et al. report increased fecal granins in patients with irritable bowel syndrome (IBS). Several interesting questions arise from their observations. Are the granins a cause of the pathophysiology or phenotype in IBS? Is the elevation of granins specific to IBS? What is the cause of increased fecal granin levels? Can fecal granin levels be used to diagnose IBS? Are increased fecal granins an expression of intestinal or colonic irritation? This paper adds to the body of evidence suggesting there are gastrointestinal disturbances in IBS; understanding these disturbances may provide clues to its pathogenesis and optimize management.
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Enteroendocrine and neuronal mechanisms in pathophysiology of acute infectious diarrhea. Dig Dis Sci 2012; 57:19-27. [PMID: 22001941 PMCID: PMC3809758 DOI: 10.1007/s10620-011-1939-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/30/2011] [Indexed: 12/30/2022]
Abstract
BACKGROUND While enterocyte secretion is the predominant mechanism considered responsible for secretory diarrhea in response to acute enteric infections, there are several lines of evidence that support alternative mechanisms controlling fluid and electrolyte secretion in diarrhea. AIM To review enteroendocrine and neuronal mechanisms that participate in the development of acute infectious diarrhea. RECENT ADVANCES Acute infectious diarrheas due to bacterial toxins (e.g., cholera, E. coli heat-stable enterotoxin, C. difficile) and rotavirus are all associated with secretion of transmitters from enteroendocrine cells (e.g., 5-HT) and activation of afferent neurons that stimulate submucosal secretomotor neurons. The latter secrete acetylcholine (which binds to muscarinic receptors on epithelial cells) and VIP. Involvement of nerves was demonstrated by inhibition of bacterial toxin-induced secretion by hexamethonium (nicotinic), tetrodotoxin (Na(+) channel blocker), and lidocaine (visceral/mucosal afferents). Nicotinic receptors are present on secretomotoneurons and these are activated by release of acetylcholine from enteric interneurons or extrinsic efferent fibers. Specific organisms also modify other mechanisms that may contribute to development of acute diarrhea. Thus, mucin secretion, activation of motor mechanisms, increased mucosal permeability and inhibition of bile acid absorption have been reported in specific types of acute infectious diarrhea. CONCLUSION New therapies targeting neural and transmitter mediation including 5-HT, VIP, NPY, as well as toxin receptors and channels activated during acute infectious diarrhea could usher in a novel approach to enhancing glucose-electrolyte solutions used in the treatment of acute diarrhea.
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Hagbom M, Istrate C, Engblom D, Karlsson T, Rodriguez-Diaz J, Buesa J, Taylor JA, Loitto VM, Magnusson KE, Ahlman H, Lundgren O, Svensson L. Rotavirus stimulates release of serotonin (5-HT) from human enterochromaffin cells and activates brain structures involved in nausea and vomiting. PLoS Pathog 2011; 7:e1002115. [PMID: 21779163 PMCID: PMC3136449 DOI: 10.1371/journal.ppat.1002115] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 04/26/2011] [Indexed: 11/18/2022] Open
Abstract
Rotavirus (RV) is the major cause of severe gastroenteritis in young children. A virus-encoded enterotoxin, NSP4 is proposed to play a major role in causing RV diarrhoea but how RV can induce emesis, a hallmark of the illness, remains unresolved. In this study we have addressed the hypothesis that RV-induced secretion of serotonin (5-hydroxytryptamine, 5-HT) by enterochromaffin (EC) cells plays a key role in the emetic reflex during RV infection resulting in activation of vagal afferent nerves connected to nucleus of the solitary tract (NTS) and area postrema in the brain stem, structures associated with nausea and vomiting. Our experiments revealed that RV can infect and replicate in human EC tumor cells ex vivo and in vitro and are localized to both EC cells and infected enterocytes in the close vicinity of EC cells in the jejunum of infected mice. Purified NSP4, but not purified virus particles, evoked release of 5-HT within 60 minutes and increased the intracellular Ca2+ concentration in a human midgut carcinoid EC cell line (GOT1) and ex vivo in human primary carcinoid EC cells concomitant with the release of 5-HT. Furthermore, NSP4 stimulated a modest production of inositol 1,4,5-triphosphate (IP3), but not of cAMP. RV infection in mice induced Fos expression in the NTS, as seen in animals which vomit after administration of chemotherapeutic drugs. The demonstration that RV can stimulate EC cells leads us to propose that RV disease includes participation of 5-HT, EC cells, the enteric nervous system and activation of vagal afferent nerves to brain structures associated with nausea and vomiting. This hypothesis is supported by treating vomiting in children with acute gastroenteritis with 5-HT3 receptor antagonists. Rotavirus (RV) can cause severe dehydration and is a leading cause of childhood deaths worldwide. While most deaths occur due to excessive loss of fluids and electrolytes through vomiting and diarrhoea, the pathophysiological mechanisms that underlie this life-threatening disease remain to be clarified. Our previous studies revealed that drugs that inhibit the function of the enteric nervous system can reduce symptoms of RV disease in mice. In this study we have addressed the hypothesis that RV infection triggers the release of serotonin (5-hydroxytryptamine, 5-HT) from enterochromaffin (EC) cells in the intestine leading to activation of vagal afferent nerves connected to brain stem structures associated with vomiting. RV activated Fos expression in the nucleus of the solitary tract of CNS, the main target for incoming fibers from the vagal nerve. Both secreted and recombinant forms of the viral enterotoxin (NSP4), increased intracellular Ca2+ concentration and released 5-HT from EC cells. 5-HT induced diarrhoea in mice within 60 min, thereby supporting the role of 5-HT in RV disease. Our study provides novel insight into the complex interaction between RV, EC cells, 5-HT and nerves.
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Affiliation(s)
- Marie Hagbom
- Division of Molecular Virology, Medical Faculty, University of Linköping, Linköping, Sweden
| | - Claudia Istrate
- Division of Molecular Virology, Medical Faculty, University of Linköping, Linköping, Sweden
- Unidade de Biologia Molecular, Centro de Malaria e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal
| | - David Engblom
- Division of Cell Biology, Medical Faculty, University of Linköping, Linköping, Sweden
| | - Thommie Karlsson
- Division of Medical Microbiology, Medical Faculty, University of Linköping, Linköping, Sweden
| | - Jesus Rodriguez-Diaz
- Department of Microbiology, School of Medicine, University of Valencia, Valencia, Spain
| | - Javier Buesa
- Department of Microbiology, School of Medicine, University of Valencia, Valencia, Spain
| | - John A. Taylor
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Vesa-Matti Loitto
- Division of Medical Microbiology, Medical Faculty, University of Linköping, Linköping, Sweden
| | - Karl-Eric Magnusson
- Division of Medical Microbiology, Medical Faculty, University of Linköping, Linköping, Sweden
| | - Håkan Ahlman
- Department of Surgery, University of Gothenburg, Gothenburg, Sweden
| | - Ove Lundgren
- Department of Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Lennart Svensson
- Division of Molecular Virology, Medical Faculty, University of Linköping, Linköping, Sweden
- * E-mail:
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Abstract
PURPOSE OF REVIEW Two independent serotonin systems exist, one in the brain and the other in the periphery. Serotonin is a well known monoaminergic neurotransmitter in the central nervous system and it is known to regulate feeding behavior, meal size, and body weight. On the other hand, there is much less evidence for the role of serotonin as a gastrointestinal hormone, particularly with respect to its effects on glucose and lipid metabolism. This review summarizes our current understanding of the role of peripheral serotonin on glucose and lipid metabolism and the implications of this for further research. RECENT FINDINGS The enterochromaffin cells of the gastrointestinal tract produce peripheral serotonin postprandially. In mice, it induces a decrease in the concentration of circulating lipids as well as hyperglycemia and hyperinsulinemia through its action on several serotonin receptors. Further, serotonin metabolites act as endogenous agonists for peroxisome proliferator-activated receptor γ and serotonin accelerates adipocyte differentiation via serotonin receptor 2A and 2C. Studies of serotonin are likely to provide new insights into the field of lipid accumulation and metabolism. SUMMARY Recent studies show new physiological functions of peripheral serotonin, linked to glucose and lipid metabolism. Peripheral serotonin may serve as an attractive new therapeutic target for the treatment of metabolic disorders in the near future.
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Affiliation(s)
- Hitoshi Watanabe
- Cellular Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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Rhee SH. Basic and translational understandings of microbial recognition by toll-like receptors in the intestine. J Neurogastroenterol Motil 2011; 17:28-34. [PMID: 21369489 PMCID: PMC3042215 DOI: 10.5056/jnm.2011.17.1.28] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 12/22/2010] [Accepted: 12/28/2010] [Indexed: 12/16/2022] Open
Abstract
Microbial recognition by multicellular organisms is initially accomplished by a group of pattern recognition receptors which are specialized to recognize microbe-associated molecular patterns (MAMPs) such as lipopolysaccharide, bacterial lipoprotein, CpG DNA motif, double strand RNA and flagellin. Toll-like receptors (TLRs) are the representative pattern recognition receptors, and microbial recognition by TLRs elicits innate and inflammatory responses. Ten TLR family members have been presently identified in human genome, and numerous studies discovered that intracellular responses from MAMPs-TLR engagements are mediated by a participation of at least 4 immediate adaptor molecules such as myeloid differentiation primary response gene-88 (MyD88), MyD88 adaptor-like (Mal) (also known as Toll/IL-1 receptor domain-containing adaptor protein [TIRAP]), Toll/IL-1 receptor domain-containing adaptor-inducing interferon-β (TRIF) and TRIF-related adaptor molecule (TRAM) leading to activate transcription factors including nuclear factor κB, activator protein-1 and interferon-regulatory factors. Given that large amounts of commensal microbiota constantly reside in the intestinal lumen, enteric microbial recognition by TLRs at the intestinal epithelium provides a critical impact on regulating intestinal homeostasis. Indeed, aberrant TLR4 and TLR5 activations are etiologically associated with the development and progress of intestinal inflammatory diseases including inflammatory bowel disease and necrotizing enterocolitis. In this review article, we present the molecular mechanism by which TLRs elicit intracellular signal transduction, and summarize the physiological relevance of TLRs related to the gastrointestinal tract.
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Affiliation(s)
- Sang Hoon Rhee
- Division of Digestive Diseases, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
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35
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Watanabe H, Akasaka D, Ogasawara H, Sato K, Miyake M, Saito K, Takahashi Y, Kanaya T, Takakura I, Hondo T, Chao G, Rose MT, Ohwada S, Watanabe K, Yamaguchi T, Aso H. Peripheral serotonin enhances lipid metabolism by accelerating bile acid turnover. Endocrinology 2010; 151:4776-86. [PMID: 20685881 DOI: 10.1210/en.2009-1349] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Serotonin is synthesized by two distinct tryptophan hydroxylases, one in the brain and one in the periphery. The latter is known to be unable to cross the blood-brain barrier. These two serotonin systems have apparently independent functions, although the functions of peripheral serotonin have yet to be fully elucidated. In this study, we have investigated the physiological effect of peripheral serotonin on the concentrations of metabolites in the circulation and in the liver. After fasting, mice were ip injected with 1 mg serotonin. The plasma glucose concentration was significantly elevated between 60 and 270 min after the injection. In contrast, plasma triglyceride, cholesterol, and nonesterified fatty acid concentrations were decreased. The hepatic glycogen synthesis and concentrations were significantly higher at 240 min. At the same time, the hepatic triglyceride content was significantly lower than the basal levels noted before the serotonin injection, whereas the hepatic cholesterol content was significantly higher by 60 min after the injection. Furthermore, serotonin stimulated the contraction of the gallbladder and the excretion of bile. After the serotonin injection, there was a significant induction of apical sodium-dependent bile acid transporter expression, resulting in a decrease in the concentration of bile acids in the feces. Additionally, data are presented to show that the functions of serotonin are mediated through diverse serotonin receptor subtypes. These data indicate that peripheral serotonin accelerates the metabolism of lipid by increasing the concentration of bile acids in circulation.
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Affiliation(s)
- Hitoshi Watanabe
- Cellular Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
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36
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Abstract
In addition to their classical functions in aiding the digestion and absorption of lipids, bile acids are increasingly gaining appreciation for their roles in regulating intestinal physiology. Bile acids are now widely considered as hormones that exert a wide range of physiological and pathophysiological effects both within and outside the gastrointestinal (GI) tract. The discovery of the bile acid receptor, GpBAR1, represented a major step forward in our understanding of how cells can sense and respond to bile acids. GpBAR1 is a cell surface G protein-coupled receptor expressed on adipose tissue and skeletal muscle where it has been found to be an important regulator of cellular metabolism. In a paper published in the current issue of Neurogastroenterology and Motility, Poole et al. investigated the expression and function of GpBAR1 in mouse intestine. They found the receptor to be expressed throughout the GI tract but predominantly on nerves within the myenteric and submucosal plexuses. Employing in vitro and in vivo techniques they demonstrated that activation of GpBAR1 by bile acids inhibits small and large intestinal motor function and delays intestinal transit. The effects of GpBAR1 activation are mediated through activation of cholinergic and nitrergic interneurons. The data reported by Poole et al. provides novel and exciting insights into how bile acids exert their actions in the intestine. This Editorial Viewpoint aims to further consider the potential physiological and pathophysiological implications of their findings.
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Affiliation(s)
- S J Keely
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland.
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37
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Garcia MAS, Yang N, Quinton PM. Normal mouse intestinal mucus release requires cystic fibrosis transmembrane regulator-dependent bicarbonate secretion. J Clin Invest 2009; 119:2613-22. [PMID: 19726884 DOI: 10.1172/jci38662] [Citation(s) in RCA: 217] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Accepted: 07/01/2009] [Indexed: 12/16/2022] Open
Abstract
The mechanisms underlying mucus-associated pathologies in cystic fibrosis (CF) remain obscure. However, recent studies indicate that CF transmembrane conductance regulator (CFTR) is required for bicarbonate (HCO3-) transport and that HCO3- is critical for normal mucus formation. We therefore investigated the role of HCO3- in mucus secretion using mouse small intestine segments ex vivo. Basal rates of mucus release in the presence or absence of HCO3- were similar. However, in the absence of HCO3-, mucus release stimulated by either PGE2 or 5-hydroxytryptamine (5-HT) was approximately half that stimulated by these molecules in the presence of HCO3-. Inhibition of HCO3- and fluid transport markedly reduced stimulated mucus release. However, neither absence of HCO3- nor inhibition of HCO3- transport affected fluid secretion rates, indicating that the effect of HCO3- removal on mucus release was not due to decreased fluid secretion. In a mouse model of CF (mice homozygous for the most common human CFTR mutation), intestinal mucus release was minimal when stimulated with either PGE2 or 5-HT in the presence or absence of HCO3-. These data suggest that normal mucus release requires concurrent HCO3- secretion and that the characteristically aggregated mucus observed in mucin-secreting organs in individuals with CF may be a consequence of defective HCO3- transport.
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Affiliation(s)
- Mary Abigail S Garcia
- Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of California School of Medicine, San Diego, California 92093-0831, USA
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38
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Kojima SI, Ikeda M, Kamikawa Y. Further investigation into the mechanism of tachykinin NK(2) receptor-triggered serotonin release from guinea-pig proximal colon. J Pharmacol Sci 2009; 110:122-6. [PMID: 19423952 DOI: 10.1254/jphs.09032sc] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The effects of the monoamine oxidase A (MAO-A) inhibitor clorgyline, the L-type calcium-channel blocker nicardipine, the syntaxin inhibitor botulinum toxin type C, and the potent thiol-oxidant phenylarsine oxide (PAO) on the selective tachykinin NK(2)-receptor agonist [beta-Ala(8)]-neurokinin A(4-10) [betaAla-NKA-(4-10)]-evoked 5-hydroxytryptamine (5-HT) outflow from colonic enterochromaffin (EC) cells was investigated in vitro using isolated guinea-pig proximal colon. The betaAla-NKA-(4-10)-evoked outflow of 5-HT from clorgyline-treated colonic strips was markedly higher than that from clorgyline-untreated colonic strips. The betaAla-NKA-(4-10)-evoked 5-HT outflow from the clorgyline-treated colonic strips was sensitive to nicardipine or botulinum toxin type C. Moreover, PAO concentration-dependently suppressed the betaAla-NKA-(4-10)-evoked 5-HT outflow from the clorgyline-treated colonic strips. The suppressant action of PAO was reversed by the reducing agent dithiothrietol, but was not blocked by the protein tyrosine kinase inhibitor genistein. These results suggest that the tachykinin NK(2) receptor-triggered 5-HT release from guinea-pig colonic EC cells is mediated by syntaxin-related exocytosis mechanisms and that colonic mucosa MAO-A activity has the important function of modulating the tachykinin NK(2) receptor-triggered 5-HT release. It also appears that PAO-mediated sulfhydryl oxidation plays a role in modulating the tachykinin NK(2) receptor-triggered 5-HT release through a mechanism independent of inhibition of protein tyrosine phosphatase activity.
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Affiliation(s)
- Shu-Ichi Kojima
- Department of Pharmacology, Dokkyo Medical University School of Medicine, Japan.
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39
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Role of serotonin in gastrointestinal motility and irritable bowel syndrome. Clin Chim Acta 2009; 403:47-55. [DOI: 10.1016/j.cca.2009.01.028] [Citation(s) in RCA: 170] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 01/17/2009] [Accepted: 01/19/2009] [Indexed: 12/18/2022]
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40
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Abstract
While bidirectional brain-gut interactions are well known mechanisms for the regulation of gut function in both healthy and diseased states, a role of the enteric flora--including both commensal and pathogenic organisms--in these interactions has only been recognized in the past few years. The brain can influence commensal organisms (enteric microbiota) indirectly, via changes in gastrointestinal motility and secretion, and intestinal permeability, or directly, via signaling molecules released into the gut lumen from cells in the lamina propria (enterochromaffin cells, neurons, immune cells). Communication from enteric microbiota to the host can occur via multiple mechanisms, including epithelial-cell, receptor-mediated signaling and, when intestinal permeability is increased, through direct stimulation of host cells in the lamina propria. Enterochromaffin cells are important bidirectional transducers that regulate communication between the gut lumen and the nervous system. Vagal, afferent innervation of enterochromaffin cells provides a direct pathway for enterochromaffin-cell signaling to neuronal circuits, which may have an important role in pain and immune-response modulation, control of background emotions and other homeostatic functions. Disruption of the bidirectional interactions between the enteric microbiota and the nervous system may be involved in the pathophysiology of acute and chronic gastrointestinal disease states, including functional and inflammatory bowel disorders.
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41
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Kidd M, Modlin IM, Gustafsson BI, Drozdov I, Hauso O, Pfragner R. Luminal regulation of normal and neoplastic human EC cell serotonin release is mediated by bile salts, amines, tastants, and olfactants. Am J Physiol Gastrointest Liver Physiol 2008; 295:G260-72. [PMID: 18556422 DOI: 10.1152/ajpgi.00056.2008] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mechanisms by which gut luminal content regulates secretion and motility are ill understood. We evaluated whether neuroendocrine enterochromaffin (EC) cells act as luminal sensors for a wide variety of nutrients and defined the secretory mechanisms of this process. Pure (98-99%) FACS-sorted human EC cells and neoplastic EC cells (KRJ-I) were studied. RT-PCR identified transcripts for T2R1 (bitter), OR1G1 (class II olfactory) and trace amine (TAR1) G protein-coupled receptors (GPCRs) and transporters for glutamine (SNAT1/2), glucose (GLUT1/3/SGLT1), and bile salts (ABST). Glutamine and sodium deoxycholate stimulated 5-HT release (EC(50) = 0.002-0.2 microM; 2-fold release) but were 10-100 times more potent in neoplastic EC cells, which also secreted 6-13 times more 5-HT. Tastants (caffeine, tyramine, octopamine) and olfactants (thymol and eugenol) also stimulated normal and neoplastic EC cell 5-HT secretion (EC(50) = 1.2 nM to 2.1 microM and 0.05 nM to 0.1 microM release, respectively); 2-deoxyglucose and the artificial sweetener sucralose also stimulated (EC(50) = 9.2 and 0.38 nM). 5-HT release was associated with ERK phosphorylation (1.5-fold, P < 0.02) and could be inhibited by a somatostatin analog (IC(50) = 1 pM). Eleven secretory associated genes including the vesicle docking inhibitor STXBP3 were upregulated in response to glutamine and bile salt stimulation in neoplastic EC cells. Targeting STXBP3 expression by use of antisense knockdown significantly (P < 0.05) reduced 5-HT secretion. In conclusion, EC cells express GPCRs and transporters for luminal tastants, olfactants, glutamine, glucose, and bile salts. Activation includes a panel of secretory genes, ERK phosphorylation, and 5-HT secretion. Luminal EC cell regulation is likely to be as important as G cell regulation in gastric acid secretion; development of agents to target EC cell function is therefore a critical therapeutic goal.
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Affiliation(s)
- Mark Kidd
- 1Gastrointestinal Pathobiology Research Group, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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Larsson MH, Sapnara M, Thomas EA, Bornstein JC, Lindström E, Svensson DJ, Sjövall H. Pharmacological analysis of components of the change in transmural potential difference evoked by distension of rat proximal small intestine in vivo. Am J Physiol Gastrointest Liver Physiol 2008; 294:G165-73. [PMID: 17975133 DOI: 10.1152/ajpgi.00264.2007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The reflex response to distension of the small intestine in vivo is complex and not well understood. The aim of this study was to characterize the neural mechanisms contributing to the complex time course of the intestinal secretory response to distension. Transmucosal potential difference (PD) was used as a marker for mucosal chloride secretion, which reflects the activity of the secretomotor neurons. Graded distensions (5, 10, and 20 mmHg) of distal rat duodenum with saline for 5 min induced a biphasic PD response with an initial peak (rapid response) followed by a plateau (sustained response). The rapid response was significantly reduced by the neural blockers tetrodotoxin and lidocaine (given serosally) and by intravenous (iv) administration of the ganglionic blocker hexamethonium and the NK(1) receptor antagonist SR-140333. Serosal TTX and iv SR-140333 significantly reduced the sustained response, which was also reduced by the NK(3) receptor antagonist talnetant and by the vasoactive intestinal polypeptide (VPAC) receptor antagonist [4Cl-d-Phe(6), Leu(17)]-VIP. Serosal lidocaine and iv hexamethonium had no significant effect on this component. Inhibition of nitric oxide synthase had no effect on any of the components of the PD response to distension. The PD response to distension thus seems to consist of two components, a rapidly activating and adapting component operating via nicotinic transmission and NK(1) receptors, and a slow component operating via VIP-ergic transmission and involving both NK(1) and NK(3) receptors.
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Affiliation(s)
- Marie H Larsson
- Department of Integrative Pharmacology, AstraZeneca R & D, Mölndal S-431 83, Sweden.
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Orandle MS, Veazey RS, Lackner AA. Enteric ganglionitis in rhesus macaques infected with simian immunodeficiency virus. J Virol 2007; 81:6265-75. [PMID: 17392357 PMCID: PMC1900106 DOI: 10.1128/jvi.02671-06] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gastrointestinal (GI) disease is a debilitating feature of human immunodeficiency virus (HIV) infection that can occur in the absence of histopathological abnormalities or identifiable enteropathogens. However, the mechanisms of GI dysfunction are poorly understood. The present study was undertaken to characterize changes in resident and inflammatory cells in the enteric nervous system (ENS) of macaques during the acute stage of simian immunodeficiency virus (SIV) infection to gain insight into potential pathogenic mechanisms of GI disease. Ganglia from duodenum, ileum, and colon were examined in healthy and acutely infected macaques by using a combination of routine histology, double-label immunofluorescence and in situ hybridization. Evaluation of tissues from infected macaques showed progressive infiltration of myenteric ganglia by CD3+ T cells and IBA1+ macrophages beginning as early as 8 days postinfection. Quantitative image analysis revealed that the severity of myenteric ganglionitis increased with time after SIV infection and, in general, was more severe in ganglia from the small intestine than in ganglia from the colon. Despite an abundance of inflammatory cells in myenteric ganglia during acute infection, the ENS was not a target for virus infection. This study provides evidence that the ENS may be playing a role in the pathogenesis of GI disease and enteropathy in HIV-infected people.
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Affiliation(s)
- Marlene S Orandle
- Department of Pathobiological Sciences, Louisiana State University, School of Veterinary Medicine, Baton Rouge, LA 70803, USA.
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Abstract
Endocrine cells, enteric neurons and enterocytes provide an integrated functional defense against luminal factors, including nutrients, microbes and toxins. Prominent among intrinsic mediators is peptide YY (PYY) which is present in approximately 50% of colorectal endocrine cells and neuropeptide Y (NPY), a neurotransmitter expressed in submucous and myenteric nerves. Both peptides and their long fragments (PYY(3-36) and NPY(3-36)) are potent, long-lasting anti-secretory agents in vitro and in vivo and, they provide significant Y receptor-mediated absorptive tone in human and mouse colon mucosa. The main function of the colon is to absorb 90% of approximately 2l of daily ileal effluent (in adult humans) and Y-absorptive tone can contribute significantly to this electrolyte absorption. Blockade or loss of this mucosal Y-absorptive tone (i.e. with Y(1) or Y(2) antagonists) leads to hypersecretion and potentially to diarrhea, so Y agonists are predicted to rescue absorption by mimicking endogenous neuroendocrine PYY or neuronal NPY.
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Affiliation(s)
- Helen M Cox
- Wolfson Centre for Age-Related Diseases, King's College London, School of Biomedical and Health Sciences, Guy's Campus, Hodgkin Building, London SE1 1UL, UK.
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O'Hara JR, Skinn AC, MacNaughton WK, Sherman PM, Sharkey KA. Consequences of Citrobacter rodentium infection on enteroendocrine cells and the enteric nervous system in the mouse colon. Cell Microbiol 2006; 8:646-60. [PMID: 16548890 DOI: 10.1111/j.1462-5822.2005.00657.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We tested the hypothesis that Citrobacter rodentium infection leads to changes in the mucosal enteroendocrine signalling and the enteric nervous system and that the host's immune response contributes to these changes. Enteroendocrine cells, serotonin (5-HT) reuptake transporter (SERT), 5-HT release, and inducible nitric oxide synthase (iNOS) expression were assessed in the colon of infected wild-type or severe combined immunodeficient (SCID) mice. Immunoreactivity for iNOS and neuropeptides were examined in the submucosal and myenteric plexuses. Mice were orogastrically infected with C. rodentium and experiments were conducted during the injury phase (10 days) and the recovery phase (30 days). 5-HT and somatostatin enteroendocrine cells and SERT were significantly reduced 10 days after infection, with numbers returning to control values at 30 days. 5-HT release was increased at 10 days. Changes to the mucosal serotonin signalling system were not observed in SCID mice. iNOS immunoreactivity was increased in the submucosa and mucosa at 10 days and returned to baseline levels by 30 days. No differences were observed in neuropeptide or iNOS immunoreactivity in the enteric plexuses following infection. The host's immune response underlies changes to enteroendocrine cells, SERT expression and 5-HT release in C. rodentium infection. These changes could contribute to disturbances in gut function arising from enteric infection.
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Affiliation(s)
- Jennifer R O'Hara
- Gastrointestinal Inflammation Research Group, Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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Mitsui R, Ono S, Karaki S, Kuwahara A. Neural and non-neural mediation of propionate-induced contractile responses in the rat distal colon. Neurogastroenterol Motil 2005; 17:585-94. [PMID: 16078948 DOI: 10.1111/j.1365-2982.2005.00669.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Short-chain fatty acids (SCFAs), including propionate, butyrate and acetate, are fermentation products of carbohydrates in the colon. We investigated the contractile effects of SCFAs on the rat distal colon. Mechanical activity of the circular muscle in strip preparations was recorded in vitro. Propionate and butyrate concentration-dependently (10 micromol L(-1)-10 mmol L(-1)) induced rapid, large amplitude phasic contractions (the first phase) followed by tonic contractions (the second phase). Acetate itself had no effect on muscle activity, although preincubation with acetate attenuated both phases of the propionate-induced response. The propionate-induced phasic contraction was attenuated by atropine, tetrodotoxin and the 5-HT4 receptor antagonist SB-204070. The propionate-induced tonic contraction was attenuated by the cyclo-oxygenase inhibitor piroxicam. Antagonists of 5-HT1A, 5-HT2A and 5-HT3 receptors had no effect on the responses. Propionate-induced responses were not observed in mucosa-free preparations. These results suggest that propionate acts on receptors in the mucosa causing the release of 5-HT from enterochromaffin cells. 5-HT acts through 5-HT4 receptors on the endings of intrinsic primary afferent neurones that in turn activate cholinergic motor neurones that contract the circular muscle. Propionate also causes tonic contraction, via prostaglandin release, in the rat distal colon.
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Affiliation(s)
- R Mitsui
- Laboratory of Physiology, Graduate School of Nutritional and Environmental Sciences, Institute for Environmental Sciences, University of Shizuoka, Shizuoka, Japan
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O'Hara JR, Ho W, Linden DR, Mawe GM, Sharkey KA. Enteroendocrine cells and 5-HT availability are altered in mucosa of guinea pigs with TNBS ileitis. Am J Physiol Gastrointest Liver Physiol 2004; 287:G998-1007. [PMID: 15231483 DOI: 10.1152/ajpgi.00090.2004] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Enteroendocrine cells act as sensory transducers, releasing 5-HT and numerous peptides that are involved in regulating motility, secretion, and gut sensation. The action of mucosal 5-HT is terminated by a 5-HT reuptake transporter (SERT). In this study, we examined the hypothesis that ileitis leads to changes in enteroendocrine cell populations and mucosal 5-HT availability. Ileitis was induced in guinea pigs by intraluminal injection of 2,4,6-trinitrobenzenesulfonic acid and experiments were conducted 3, 7, and 14 days after treatment. The number of somatostatin, neurotensin, and 5-HT-immunoreactive cells increased at 3 and 7 days of ileitis, respectively, whereas no significant changes in the numbers of cholecystokinin, glucagon-like peptide-2, glucose-dependent insulinotropic peptide, and peptide YY-immunoreactive cells were observed. Chemical stimulation of the inflamed mucosa with sodium deoxycholic acid significantly increased 5-HT release compared with basal release. Mechanical stimulation of the mucosa potentiated the effect of the chemical stimuli at day 7. Epithelial SERT immunoreactivity was significantly reduced during the time course of inflammation. Thus changes in enteroendocrine cell populations and 5-HT availability could contribute to the altered motility and secretion associated with intestinal inflammation by disrupting mucosal signaling to enteric nerves involved in peristaltic and secretory reflexes.
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Affiliation(s)
- Jennifer R O'Hara
- Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
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Mourad FH. Animal and human models for studying effects of drugs on intestinal fluid transport in vivo. J Pharmacol Toxicol Methods 2004; 50:3-12. [PMID: 15233962 DOI: 10.1016/j.vascn.2003.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2003] [Accepted: 12/22/2003] [Indexed: 11/18/2022]
Abstract
The understanding of the physiology and pathophysiology of intestinal fluid transport has been derived from animal and human models of normal and perturbed intestines. This understanding helped in designing drugs and changing the composition of oral rehydration solutions in a targeted manner to affect intestinal fluid absorption/secretion that was tested both in vitro and in vivo before embarking on clinical trials. In this review, in vivo techniques used to study water transport in both animal and human models are described. In particular, steady state intestinal perfusion techniques, closed segment techniques, fistulous animal models, balance study models, enteropooling models, and isotope tracer models are reviewed. Advantages and drawbacks of each technique and examples where drug effects have been studied in a particular model are provided.
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Affiliation(s)
- Fadi H Mourad
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut Medical Center, P.O. Box 113-6044, Hamra 110-32090, Beirut, Lebanon.
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Izzo AA, Capasso F, Costagliola A, Bisogno T, Marsicano G, Ligresti A, Matias I, Capasso R, Pinto L, Borrelli F, Cecio A, Lutz B, Mascolo N, Di Marzo V. An endogenous cannabinoid tone attenuates cholera toxin-induced fluid accumulation in mice. Gastroenterology 2003; 125:765-74. [PMID: 12949722 DOI: 10.1016/s0016-5085(03)00892-8] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Cholera toxin (CT) is the most recognizable enterotoxin causing secretory diarrhea, a major cause of infant morbidity and mortality throughout the world. In this study, we investigated the role of the endogenous cannabinoid system (i.e., the cannabinoid receptors and their endogenous ligands) in CT-induced fluid accumulation in the mouse small intestine. METHODS Fluid accumulation was evaluated by enteropooling; endocannabinoid levels were measured by isotope-dilution gas chromatography mass spectrometry; CB(1) receptors were localized by immunohistochemistry and their messenger RNA (mRNA) levels were quantified by reverse-transcription polymerase chain reaction (PCR). RESULTS Oral administration of CT to mice resulted in an increase in fluid accumulation in the small intestine and in increased levels of the endogenous cannabinoid, anandamide, and increased expression of the cannabinoid CB(1) receptor mRNA. The cannabinoid receptor agonist CP55,940 and the selective cannabinoid CB(1) receptor agonist arachidonoyl-chloro-ethanolamide inhibited CT-induced fluid accumulation, and this effect was counteracted by the CB(1) receptor antagonist SR141716A, but not by the CB(2) receptor antagonist SR144528. SR141716A, per se, but not the vanilloid VR1 receptor antagonist capsazepine, enhanced fluid accumulation induced by CT, whereas the selective inhibitor of anandamide cellular uptake, VDM11, prevented CT-induced fluid accumulation. CONCLUSIONS These results indicate that CT, along with enhanced intestinal secretion, causes overstimulation of endocannabinoid signaling with an antisecretory role in the small intestine.
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Affiliation(s)
- Angelo A Izzo
- Department of Experimental Pharmacology, University of Naples, "Frederico II", Naples, Italy.
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Fihn BM, Sjöqvist A, Jodal M. Involvement of enteric nerves in permeability changes due to deoxycholic acid in rat jejunum in vivo. ACTA PHYSIOLOGICA SCANDINAVICA 2003; 178:241-50. [PMID: 12823182 DOI: 10.1046/j.1365-201x.2003.01144.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIM Stress and Clostridium difficile toxin A increase epithelial permeability in the small intestine via vagus and visceral afferents, in turn activating mucosal mast cells. Bile acids also increase epithelial permeability but it is not known if nerves or mast cells are involved in this effect in the small intestine. METHOD In jejunum of anesthetized rats, the effects of hexamethonium and atropine on deoxycholic acid (DCA) induced fluid secretion and increase in epithelial permeability was therefore studied by determining the appearance and disappearance rates of 14C-mannitol and 51Cr-EDTA into and from a perfusion system containing 4 or 8 mm DCA and expressed as clearance. RESULTS DCA increased net fluid transport and appearance and to a less extent disappearance rates of the probes. Hexamethonium but not atropine, chronic denervation or the NO synthase inhibitor L-NNA did significantly decrease the appearance rate and net fluid secretion. The levels of the mast cell protease II (RMCP II) in perfusate and plasma were not increased by DCA. The clearance ratio Cr-EDTA/mannitol indicates that the plasma clearance of the permeability probes is partly secondary to net fluid transport only at higher DCA concentrations. CONCLUSION We conclude that the DCA effect on epithelial permeability is to a large part induced by intramural reflex(es) containing nicotinic receptors. The results also suggest that mast cell degranulation and NO release are not involved in the mechanism. This indicates that the nerve effect on intestinal paracellular permeability is not mediated by the mechanisms described for stress or Clostridium difficile toxin A.
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Affiliation(s)
- B-M Fihn
- Department of Physiology, University of Göteborg, Göteborg, Sweden
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