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Chang H, Perkins MH, Novaes LS, Qian F, Zhang T, Neckel PH, Scherer S, Ley RE, Han W, de Araujo IE. Stress-sensitive neural circuits change the gut microbiome via duodenal glands. Cell 2024; 187:5393-5412.e30. [PMID: 39121857 PMCID: PMC11425084 DOI: 10.1016/j.cell.2024.07.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 05/13/2024] [Accepted: 07/12/2024] [Indexed: 08/12/2024]
Abstract
Negative psychological states impact immunity by altering the gut microbiome. However, the relationship between brain states and microbiome composition remains unclear. We show that Brunner's glands in the duodenum couple stress-sensitive brain circuits to bacterial homeostasis. Brunner's glands mediated the enrichment of gut Lactobacillus species in response to vagus nerve stimulation. Cell-specific ablation of the glands markedly suppressed Lactobacilli counts and heightened vulnerability to infection. In the forebrain, we mapped a vagally mediated, polysynaptic circuit connecting the central nucleus of the amygdala to Brunner's glands. Chronic stress suppressed central amygdala activity and phenocopied the effects of gland lesions. Conversely, excitation of either the central amygdala or parasympathetic vagal neurons activated Brunner's glands and reversed the effects of stress on the gut microbiome and immunity. The findings revealed a tractable brain-body mechanism linking psychological states to host defense.
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Affiliation(s)
- Hao Chang
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Matthew H Perkins
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Leonardo S Novaes
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | | | - Tong Zhang
- Department of General Surgery, Guangzhou First People's Hospital, Guangzhou 510180, Guangdong, China; Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Disease, Guangzhou Medical University, Guangzhou 510180, Guangdong, China
| | - Peter H Neckel
- Institute of Clinical Anatomy and Cell Analysis, University of Tübingen, Tübingen 72074, Germany
| | - Simon Scherer
- Department of Pediatric Surgery and Pediatric Urology, University Children's Hospital, Tübingen 72076, Germany
| | - Ruth E Ley
- Max-Planck Institute for Biology, Tübingen 72076, Germany
| | - Wenfei Han
- Max-Planck Institute for Biological Cybernetics, Tübingen 72076, Germany.
| | - Ivan E de Araujo
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Max-Planck Institute for Biological Cybernetics, Tübingen 72076, Germany.
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Chang H, Perkins MH, Novaes LS, Qian F, Han W, de Araujo IE. An Amygdalar-Vagal-Glandular Circuit Controls the Intestinal Microbiome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.02.594027. [PMID: 38853855 PMCID: PMC11160750 DOI: 10.1101/2024.06.02.594027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Psychological states can regulate intestinal mucosal immunity by altering the gut microbiome. However, the link between the brain and microbiome composition remains elusive. We show that Brunner's glands in the duodenal submucosa couple brain activity to intestinal bacterial homeostasis. Brunner's glands mediated the enrichment of gut probiotic species in response to stimulation of abdominal vagal fibers. Cell-specific ablation of the glands triggered transmissible dysbiosis associated with an immunodeficiency syndrome that led to mortality upon gut infection with pathogens. The syndrome could be largely prevented by oral or intra-intestinal administration of probiotics. In the forebrain, we identified a vagally-mediated, polysynaptic circuit connecting the glands of Brunner to the central nucleus of the amygdala. Intra-vital imaging revealed that excitation of central amygdala neurons activated Brunner's glands and promoted the growth of probiotic populations. Our findings unveil a vagal-glandular neuroimmune circuitry that may be targeted for the modulation of the gut microbiome. The glands of Brunner may be the critical cells that regulate the levels of Lactobacilli species in the intestine.
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Sharkey KA, Mawe GM. The enteric nervous system. Physiol Rev 2023; 103:1487-1564. [PMID: 36521049 PMCID: PMC9970663 DOI: 10.1152/physrev.00018.2022] [Citation(s) in RCA: 70] [Impact Index Per Article: 70.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
Of all the organ systems in the body, the gastrointestinal tract is the most complicated in terms of the numbers of structures involved, each with different functions, and the numbers and types of signaling molecules utilized. The digestion of food and absorption of nutrients, electrolytes, and water occurs in a hostile luminal environment that contains a large and diverse microbiota. At the core of regulatory control of the digestive and defensive functions of the gastrointestinal tract is the enteric nervous system (ENS), a complex system of neurons and glia in the gut wall. In this review, we discuss 1) the intrinsic neural control of gut functions involved in digestion and 2) how the ENS interacts with the immune system, gut microbiota, and epithelium to maintain mucosal defense and barrier function. We highlight developments that have revolutionized our understanding of the physiology and pathophysiology of enteric neural control. These include a new understanding of the molecular architecture of the ENS, the organization and function of enteric motor circuits, and the roles of enteric glia. We explore the transduction of luminal stimuli by enteroendocrine cells, the regulation of intestinal barrier function by enteric neurons and glia, local immune control by the ENS, and the role of the gut microbiota in regulating the structure and function of the ENS. Multifunctional enteric neurons work together with enteric glial cells, macrophages, interstitial cells, and enteroendocrine cells integrating an array of signals to initiate outputs that are precisely regulated in space and time to control digestion and intestinal homeostasis.
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Affiliation(s)
- Keith A Sharkey
- Hotchkiss Brain Institute and Snyder Institute for Chronic Diseases, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Gary M Mawe
- Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington, Vermont
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Marie Voetmann L, Underwood CR, Rolin B, Hansen AK, Kirk RK, Pyke C, Knudsen LB, Frederiksen KS. In vitro cell cultures of Brunner's glands from male mouse to study GLP-1 receptor function. Am J Physiol Cell Physiol 2022; 322:C1260-C1269. [PMID: 35442827 DOI: 10.1152/ajpcell.00345.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Exocrine glands in the submucosa of the proximal duodenum secrete alkaline fluid containing mucus to protect the intestinal mucosa from acidic stomach contents. These glands, known as Brunner's gland, express high glucagon-like peptide 1 receptor (GLP-1R) levels. Previous studies have suggested that activation of the GLP-1R induces expression of barrier protective genes in Brunner's glands. Still, the lack of a viable in vitro culture of Brunner's glands has hampered additional studies of the functional consequences of GLP-1R activation. In this study, we established a procedure to isolate and culture cells derived from murine Brunner's glands. The isolated glandular cells retained functional GLP-1R expression in culture, making this in vitro system suitable for the study of GLP-1R activation. We found that cells derived from the Brunner's glands of mice pre-treated with semaglutide contained significantly more mucus compared to Brunner's glands from vehicle-treated mice. Our data suggest a protective intestinal response upon semaglutide treatment, but further studies are required to leverage the full potential of cultured Brunner's gland cells.
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Affiliation(s)
- Louise Marie Voetmann
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.,Global Drug Discovery, Novo Nordisk A/S, 2760 Måløv, Denmark
| | | | - Bidda Rolin
- Global Drug Discovery, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - Axel K Hansen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Rikke K Kirk
- Global Drug Discovery, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - Charles Pyke
- Global Drug Discovery, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - Lotte B Knudsen
- Global Drug Discovery, Novo Nordisk A/S, 2760 Måløv, Denmark
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Eicher AK, Kechele DO, Sundaram N, Berns HM, Poling HM, Haines LE, Sanchez JG, Kishimoto K, Krishnamurthy M, Han L, Zorn AM, Helmrath MA, Wells JM. Functional human gastrointestinal organoids can be engineered from three primary germ layers derived separately from pluripotent stem cells. Cell Stem Cell 2022; 29:36-51.e6. [PMID: 34856121 PMCID: PMC8741755 DOI: 10.1016/j.stem.2021.10.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 07/22/2021] [Accepted: 10/20/2021] [Indexed: 02/08/2023]
Abstract
Human organoid model systems lack important cell types that, in the embryo, are incorporated into organ tissues during development. We developed an organoid assembly approach starting with cells from the three primary germ layers-enteric neuroglial, mesenchymal, and epithelial precursors-that were derived separately from human pluripotent stem cells (PSCs). From these three cell types, we generated human antral and fundic gastric tissue containing differentiated glands surrounded by layers of smooth muscle containing functional enteric neurons that controlled contractions of the engineered antral tissue. Using this experimental system, we show that human enteric neural crest cells (ENCCs) promote mesenchyme development and glandular morphogenesis of antral stomach organoids. Moreover, ENCCs can act directly on the foregut to promote a posterior fate, resulting in organoids with a Brunner's gland phenotype. Thus, germ layer components that are derived separately from PSCs can be used for tissue engineering to generate complex human organoids.
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Affiliation(s)
- Alexandra K. Eicher
- College of Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA,Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA
| | - Daniel O. Kechele
- Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA
| | - Nambirajan Sundaram
- Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Pediatric General and Thoracic Surgery, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA
| | - H. Matthew Berns
- Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA
| | - Holly M. Poling
- Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Pediatric General and Thoracic Surgery, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA
| | - Lauren E. Haines
- Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA
| | - J. Guillermo Sanchez
- College of Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA,Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA
| | - Keishi Kishimoto
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA,CuSTOM-RIKEN BDR Collaborative Laboratory, CCHMC, Cincinnati, OH, 45229, USA,Laboratory for Lung Development, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, 650-0047, Japan
| | - Mansa Krishnamurthy
- Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Endocrinology, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA
| | - Lu Han
- Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA
| | - Aaron M. Zorn
- Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA
| | - Michael A. Helmrath
- Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Pediatric General and Thoracic Surgery, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA
| | - James M. Wells
- Center for Stem Cell and Organoid Medicine (CuSTOM),Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA,Division of Endocrinology, Cincinnati Children’s Hospital Medical Center (CCHMC), Cincinnati, OH, 45229, USA,Lead Contact and Corresponding Author,Corresponding Author’s:
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6
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A novel use for botulinum toxin A in the management of ileostomy and urostomy leaks. J Wound Ostomy Continence Nurs 2016; 42:83-8. [PMID: 25549312 DOI: 10.1097/won.0000000000000076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To assess the efficacy of Botulinum toxin A (BoNT-A) in the treatment of patients with hypercontractile stomas resulting in repeated pouching system failures and leaks. DESIGN Prospective case series. SUBJECTS AND SETTING Ten consecutive patients who presented to the outpatient stoma clinic with actively contractile stomas that shortened spasmodically resulting in leaks were offered treatment with BoNT-A if treatment with other measures had been unsuccessful. METHODS Following an observed reduction in the peristalsic shortening of a stoma after intradermal injection of BoNT-A for hyperhidrosis, we conducted a prospective case series of 10 patients with pouch adhesive failures attributed to spasmodic shortening of the stoma. Ten patients, 3 with urostomies and 7 with ileostomies, were offered BoNT-A injection. The first was treated cautiously with 15 units of BoNT-A injected into the muscularis layer, followed by an additional 25 units injected 1 month later. Subsequent patients received doses varying from 50 to 100 units. Ongoing treatments ranged 50 to 100 units every 3 to 6 months. RESULTS Seventy percent (n = 7) of patients reported a useful reduction in leakage and pouching system seal failures. In these 7 patients, the frequency of pouch changes changed from an average of 2.18 to 0.44 per day (over all 10 patients this was a change from an average of 2.35 per day to 1.16 per day). No adverse side effects were reported. CONCLUSION Findings from this clinical case series suggest that BoNT-A may be a promising treatment in the management of patients with leaks caused by actively contracting stomas.
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Sharkey KA, Savidge TC. Reprint of: Role of enteric neurotransmission in host defense and protection of the gastrointestinal tract. Auton Neurosci 2014; 182:70-82. [PMID: 24674836 DOI: 10.1016/j.autneu.2014.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 12/11/2013] [Indexed: 12/11/2022]
Abstract
Host defense is a vital role played by the gastrointestinal tract. As host to an enormous and diverse microbiome, the gut has evolved an elaborate array of chemical and physicals barriers that allow the digestion and absorption of nutrients without compromising the mammalian host. The control of such barrier functions requires the integration of neural, humoral, paracrine and immune signaling, involving redundant and overlapping mechanisms to ensure, under most circumstances, the integrity of the gastrointestinal epithelial barrier. Here we focus on selected recent developments in the autonomic neural control of host defense functions used in the protection of the gut from luminal agents, and discuss how the microbiota may potentially play a role in enteric neurotransmission. Key recent findings include: the important role played by subepithelial enteric glia in modulating intestinal barrier function, identification of stress-induced mechanisms evoking barrier breakdown, neural regulation of epithelial cell proliferation, the role of afferent and efferent vagal pathways in regulating barrier function, direct evidence for bacterial communication to the enteric nervous system, and microbial sources of enteric neurotransmitters. We discuss these new and interesting developments in our understanding of the role of the autonomic nervous system in gastrointestinal host defense.
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Affiliation(s)
- Keith A Sharkey
- Hotchkiss Brain Institute and Snyder Institute for Chronic Diseases, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada.
| | - Tor C Savidge
- Texas Children's Microbiome Center, Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
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8
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Role of enteric neurotransmission in host defense and protection of the gastrointestinal tract. Auton Neurosci 2013; 181:94-106. [PMID: 24412639 DOI: 10.1016/j.autneu.2013.12.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 12/11/2013] [Indexed: 12/24/2022]
Abstract
Host defense is a vital role played by the gastrointestinal tract. As host to an enormous and diverse microbiome, the gut has evolved an elaborate array of chemical and physicals barriers that allow the digestion and absorption of nutrients without compromising the mammalian host. The control of such barrier functions requires the integration of neural, humoral, paracrine and immune signaling, involving redundant and overlapping mechanisms to ensure, under most circumstances, the integrity of the gastrointestinal epithelial barrier. Here we focus on selected recent developments in the autonomic neural control of host defense functions used in the protection of the gut from luminal agents, and discuss how the microbiota may potentially play a role in enteric neurotransmission. Key recent findings include: the important role played by subepithelial enteric glia in modulating intestinal barrier function, identification of stress-induced mechanisms evoking barrier breakdown, neural regulation of epithelial cell proliferation, the role of afferent and efferent vagal pathways in regulating barrier function, direct evidence for bacterial communication to the enteric nervous system, and microbial sources of enteric neurotransmitters. We discuss these new and interesting developments in our understanding of the role of the autonomic nervous system in gastrointestinal host defense.
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9
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Collaco AM, Jakab RL, Hoekstra NE, Mitchell KA, Brooks A, Ameen NA. Regulated traffic of anion transporters in mammalian Brunner's glands: a role for water and fluid transport. Am J Physiol Gastrointest Liver Physiol 2013; 305:G258-75. [PMID: 23744739 PMCID: PMC3742856 DOI: 10.1152/ajpgi.00485.2012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The Brunner's glands of the proximal duodenum exert barrier functions through secretion of glycoproteins and antimicrobial peptides. However, ion transporter localization, function, and regulation in the glands are less clear. Mapping the subcellular distribution of transporters is an important step toward elucidating trafficking mechanisms of fluid transport in the gland. The present study examined 1) changes in the distribution of intestinal anion transporters and the aquaporin 5 (AQP5) water channel in rat Brunner's glands following second messenger activation and 2) anion transporter distribution in Brunner's glands from healthy and disease-affected human tissues. Cystic fibrosis transmembrane conductance regulator (CFTR), AQP5, sodium-potassium-coupled chloride cotransporter 1 (NKCC1), sodium-bicarbonate cotransporter (NBCe1), and the proton pump vacuolar ATPase (V-ATPase) were localized to distinct membrane domains and in endosomes at steady state. Carbachol and cAMP redistributed CFTR to the apical membrane. cAMP-dependent recruitment of CFTR to the apical membrane was accompanied by recruitment of AQP5 that was reversed by a PKA inhibitor. cAMP also induced apical trafficking of V-ATPase and redistribution of NKCC1 and NBCe1 to the basolateral membranes. The steady-state distribution of AQP5, CFTR, NBCe1, NKCC1, and V-ATPase in human Brunner's glands from healthy controls, cystic fibrosis, and celiac disease resembled that of rat; however, the distribution profiles were markedly attenuated in the disease-affected duodenum. These data support functional transport of chloride, bicarbonate, water, and protons by second messenger-regulated traffic in mammalian Brunner's glands under physiological and pathophysiological conditions.
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Affiliation(s)
- Anne M. Collaco
- 1Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut;
| | - Robert L. Jakab
- 1Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut;
| | - Nadia E. Hoekstra
- 1Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut;
| | - Kisha A. Mitchell
- 2Department of Pathology, Yale University School of Medicine, New Haven, Connecticut; and
| | - Amos Brooks
- 2Department of Pathology, Yale University School of Medicine, New Haven, Connecticut; and
| | - Nadia A. Ameen
- 1Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut; ,3Department Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
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10
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Increased duodenal expression of transforming growth factor-alpha and epidermal growth factor during experimental colitis in rats. Eur J Gastroenterol Hepatol 2008; 20:989-94. [PMID: 18787466 DOI: 10.1097/meg.0b013e3283036758] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVE/BACKGROUND Epidermal growth factor (EGF) and transforming growth factor alpha (TGFalpha) protect gastrointestinal mucosa against injury. Having shown earlier, that TGFalpha but not EGF is locally increasingly expressed after mucosal injury in the colon, we now wanted to explore the pattern of expression of EGF and TGFalpha in the remaining gastrointestinal tract and to infer from the pattern of expression, to possible signals for the induction of the growth factor expression and further mechanisms for mucosal protection. DESIGN/METHODS The trinitrobenzene sulfonic acid/ethanol-induced model of colitis in rats was used. TGFalpha-mRNA and EGF-mRNA expression was evaluated in inflamed and noninflamed colon, in the ileum, jejunum, duodenum, stomach, and in the submandibulary glands. RESULTS A significant increase of TGFalpha-mRNA and EGF-mRNA expressions was detected in the duodenal mucosa and a significant increase in TGFalpha-mRNA expression was observed in the inflamed colonic mucosa after mucosal injury in the colon within the first hours of colitis. CONCLUSION The increased expression of EGF and TGFalpha in the duodenum may lead to neutralization of gastric acid and proteolytic enzymes in the upper gastrointestinal tract during the course of colitis. Possible signals for the increased expression of EGF and TGFalpha presumably are fasting, parasympathetic, or adrenergic parts of the enteric nervous system or yet unknown mechanisms.
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11
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Cosen-Binker LI, Morris GP, Vanner S, Gaisano HY. Munc18/SNARE proteins’ regulation of exocytosis in guinea pig duodenal Brunner’s gland acini. World J Gastroenterol 2008; 14:2314-22. [PMID: 18416456 PMCID: PMC2705084 DOI: 10.3748/wjg.14.2314] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To examine the molecular mechanism of exocytosis in the Brunner’s gland acinar cell.
METHODS: We used a submucosal preparation of guinea pig duodenal Brunner’s gland acini to visualize the dilation of the ductal lumen in response to cholinergic stimulus. We correlated this to electron microscopy to determine the extent of exocytosis of the mucin-filled vesicles. We then examined the behavior of SNARE and interacting Munc18 proteins by confocal microscopy.
RESULTS: One and 6 &mgr;mol/L carbachol evoked a dose-dependent dilation of Brunner’s gland acini lumen, which correlated to the massive exocytosis of mucin. Munc18c and its cognate SNARE proteins Syntaxin-4 and SNAP-23 were localized to the apical plasma membrane, and upon cholinergic stimulation, Munc18c was displaced into the cytosol leaving Syntaxin-4 and SNAP-23 intact.
CONCLUSION: Physiologic cholinergic stimulation induces Munc18c displacement from the Brunner’s gland acinar apical plasma membrane, which enables apical membrane Syntaxin-4 and SNAP-23 to form a SNARE complex with mucin-filled vesicle SNARE proteins to affect exocytosis.
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12
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Parvin MN, Kurabuchi S, Murdiastuti K, Yao C, Kosugi-Tanaka C, Akamatsu T, Kanamori N, Hosoi K. Subcellular redistribution of AQP5 by vasoactive intestinal polypeptide in the Brunner's gland of the rat duodenum. Am J Physiol Gastrointest Liver Physiol 2005; 288:G1283-91. [PMID: 15650134 DOI: 10.1152/ajpgi.00030.2004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Aquaporin (AQP)5, an exocrine-type water channel, was detected in the rat duodenum by Western blot analysis, and was localized by immunohistochemistry in the secretory granule membranes as well as in the apical and lateral aspects of the plasma membrane of Brunner's gland cells. Incubation of duodenal slices with vasoactive intestinal polypeptide (VIP) in vitro significantly increased the amount of AQP5 in the apical membrane fraction in a dose- and time-dependent manner with the amount reaching a plateau at 100 nM VIP and becoming near maximal after a 30-s incubation. Protein kinase inhibitors, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7, 50 muM), and N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H-89; PKA-specific, 1 muM) blocked this increase, but PKC-specific inhibitor calphostin C did not, implying the involvement of PKA but not PKC in this cellular event. Intravenous injection with VIP (40 mug/kg body wt) provoked dilation of the lumen of the Brunner's gland at 2 and 7 min and increased the staining intensity of AQP5 in the apical and lateral membranes. AQP1 (both nonglycosylated and glycosylated forms) was also found to localize in the apical and basolateral membranes of cells of Brunner's gland. VIP, however, did not provoke any significant change in the AQP1 level in the apical membrane, as judged from the results of the above in vitro and in vivo experiments. These results suggest that VIP induced the exocytosis of granule contents and simultaneously caused translocation of AQP5 but not of AQP1 to the apical membrane in Brunner's gland cells.
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Affiliation(s)
- Most Nahid Parvin
- Dept. of Molecular Oral Physiology, Institute of Health Biosciences, The Univ. of Tokushima Graduate School, Tokushima-Shi, Tokushima 770-8504, Japan
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13
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Allen A, Flemström G. Gastroduodenal mucus bicarbonate barrier: protection against acid and pepsin. Am J Physiol Cell Physiol 2005; 288:C1-19. [PMID: 15591243 DOI: 10.1152/ajpcell.00102.2004] [Citation(s) in RCA: 378] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Secretion of bicarbonate into the adherent layer of mucus gel creates a pH gradient with a near-neutral pH at the epithelial surfaces in stomach and duodenum, providing the first line of mucosal protection against luminal acid. The continuous adherent mucus layer is also a barrier to luminal pepsin, thereby protecting the underlying mucosa from proteolytic digestion. In this article we review the present state of the gastroduodenal mucus bicarbonate barrier two decades after the first supporting experimental evidence appeared. The primary function of the adherent mucus gel layer is a structural one to create a stable, unstirred layer to support surface neutralization of acid and act as a protective physical barrier against luminal pepsin. Therefore, the emphasis on mucus in this review is on the form and role of the adherent mucus gel layer. The primary function of the mucosal bicarbonate secretion is to neutralize acid diffusing into the mucus gel layer and to be quantitatively sufficient to maintain a near-neutral pH at the mucus-mucosal surface interface. The emphasis on mucosal bicarbonate in this review is on the mechanisms and control of its secretion and the establishment of a surface pH gradient. Evidence suggests that under normal physiological conditions, the mucus bicarbonate barrier is sufficient for protection of the gastric mucosa against acid and pepsin and is even more so for the duodenum.
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Affiliation(s)
- Adrian Allen
- Physiological Sciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom
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14
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Kovac J, Moore B, Vanner S. Potassium currents regulating secretion from Brunner's glands in guinea pig duodenum. Am J Physiol Gastrointest Liver Physiol 2004; 286:G377-84. [PMID: 14604859 DOI: 10.1152/ajpgi.00153.2003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This study examined the role of outward K(+) currents in the acinar cells underlying secretion from Brunner's glands in guinea pig duodenum. Intracellular recordings were made from single acinar cells in intact acini in in vitro submucosal preparations, and videomicroscopy was employed in the same preparation to correlate these measures with secretion. Mean resting membrane potential was -74 mV and was depolarized by high external K(+) (20 mM) and the K(+) channel blockers 4-aminopyridine (4-AP), quinine, and clotrimazole. The cholinergic agonist carbachol (60-2,000 nM; EC(50) = 200 nM) caused a concentration-dependent initial hyperpolarization of the membrane and an associated decrease in input resistance. This hyperpolarization was significantly decreased by 20 mM external K(+) or membrane hyperpolarization and increased by 1 mM external K(+) or membrane depolarization. It was blocked by the K(+) channel blockers tetraethylammonium (TEA), 4-AP, quinine, and clotrimazole but not iberiotoxin. When videomicroscopy was employed to measure dilation of acinar lumen in the same preparation, carbachol-evoked dilations were altered in a parallel fashion when external K(+) was altered. The dilations were also blocked by the K(+) channel blockers TEA, 4-AP, quinine, and clotrimazole but not iberiotoxin. These findings suggest that activation of outward K(+) currents is fundamental to the initiation of secretion from these glands, consistent with the model of K(+) efflux from the basolateral membrane providing the driving force for secretion. The pharmacological profile suggests that these K(+) channels belong to the intermediate conductance group.
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Affiliation(s)
- Jason Kovac
- Gastrointestinal Diseases Research Unit, Queen's University Hospital, Kingston, Ontario, Canada
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