1
|
Wang CM, Fernez MT, Woolston BM, Carrier RL. Native gastrointestinal mucus: Critical features and techniques for studying interactions with drugs, drug carriers, and bacteria. Adv Drug Deliv Rev 2023; 200:114966. [PMID: 37329985 PMCID: PMC11184232 DOI: 10.1016/j.addr.2023.114966] [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: 03/02/2023] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 06/19/2023]
Abstract
Gastrointestinal mucus plays essential roles in modulating interactions between intestinal lumen contents, including orally delivered drug carriers and the gut microbiome, and underlying epithelial and immune tissues and cells. This review is focused on the properties of and methods for studying native gastrointestinal mucus and its interactions with intestinal lumen contents, including drug delivery systems, drugs, and bacteria. The properties of gastrointestinal mucus important to consider in its analysis are first presented, followed by a discussion of different experimental setups used to study gastrointestinal mucus. Applications of native intestinal mucus are then described, including experimental methods used to study mucus as a barrier to drug delivery and interactions with intestinal lumen contents that impact barrier properties. Given the significance of the microbiota in health and disease, its impact on drug delivery and drug metabolism, and the use of probiotics and microbe-based delivery systems, analysis of interactions of bacteria with native intestinal mucus is then reviewed. Specifically, bacteria adhesion to, motility within, and degradation of mucus is discussed. Literature noted is focused largely on applications of native intestinal mucus models as opposed to isolated mucins or reconstituted mucin gels.
Collapse
Affiliation(s)
- Chia-Ming Wang
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Matthew T Fernez
- Department of Chemical Engineering, Northeastern University, Boston, MA, USA
| | - Benjamin M Woolston
- Department of Chemical Engineering, Northeastern University, Boston, MA, USA
| | - Rebecca L Carrier
- Department of Bioengineering, Northeastern University, Boston, MA, USA; Department of Chemical Engineering, Northeastern University, Boston, MA, USA; Department of Biology, Northeastern University, Boston, MA, USA.
| |
Collapse
|
2
|
Dubbelboer IR, Barmpatsalou V, Rodler A, Karlsson E, Filipe Nunes S, Holmberg J, Häggström J, A. S. Bergström C. Gastrointestinal mucus in dog: physiological characteristics, composition, and structural properties. Eur J Pharm Biopharm 2022; 173:92-102. [DOI: 10.1016/j.ejpb.2022.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 11/17/2021] [Accepted: 02/23/2022] [Indexed: 11/27/2022]
|
3
|
Barmpatsalou V, Dubbelboer IR, Rodler A, Jacobson M, Karlsson E, Pedersen BL, Bergström CAS. Physiological properties, composition and structural profiling of porcine gastrointestinal mucus. Eur J Pharm Biopharm 2021; 169:156-167. [PMID: 34687897 DOI: 10.1016/j.ejpb.2021.10.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 10/12/2021] [Accepted: 10/15/2021] [Indexed: 11/18/2022]
Abstract
The gastrointestinal mucus is a hydrogel that lines the luminal side of the gastrointestinal epithelium, offering barrier protection from pathogens and lubrication of the intraluminal contents. These barrier properties likewise affect nutrients and drugs that need to penetrate the mucus to reach the epithelium prior to absorption. In order to assess the potential impact of the mucus on drug absorption, we need information about the nature of the gastrointestinal mucus. Today, most of the relevant available literature is mainly derived from rodent studies. In this work, we used a larger animal species, the pig model, to characterize the mucus throughout the length of the gastrointestinal tract. This is the first report of the physiological properties (physical appearance, pH and water content), composition (protein, lipid and metabolite content) and structural profiling (rheology and gel network) of the porcine gastrointestinal mucus. These findings allow for direct comparisons between the characteristics of mucus from various segments and can be further utilized to improve our understanding of the role of the mucus on region dependent drug absorption. Additionally, the present work is expected to contribute to the assessment of the porcine model as a preclinical species in the drug development process.
Collapse
Affiliation(s)
- Vicky Barmpatsalou
- The Swedish Drug Delivery Center, Department of Pharmacy, Uppsala University, BMC P.O. Box 580, SE-751 23, Uppsala, Sweden
| | - Ilse R Dubbelboer
- The Swedish Drug Delivery Center, Department of Pharmacy, Uppsala University, BMC P.O. Box 580, SE-751 23, Uppsala, Sweden
| | - Agnes Rodler
- The Swedish Drug Delivery Center, Department of Pharmacy, Uppsala University, BMC P.O. Box 580, SE-751 23, Uppsala, Sweden; The Swedish Drug Delivery Center, Department of Medicinal Chemistry, Uppsala University, BMC P.O. Box 574, SE-751 23, Uppsala, Sweden
| | - Magdalena Jacobson
- Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Sciences, Swedish University of Agricultural Sciences, P.O. Box 7054, SE-750 07, Uppsala, Sweden
| | - Eva Karlsson
- Oral Product Development, Pharmaceutical Technology & Development Operations, AstraZeneca, Gothenburg, Sweden
| | - Betty Lomstein Pedersen
- Product Development & Drug Delivery, Global Pharmaceutical R&D, Ferring Pharmaceuticals A/S, Kay Fiskers Plads 11, DK-2300, Copenhagen, Denmark
| | - Christel A S Bergström
- The Swedish Drug Delivery Center, Department of Pharmacy, Uppsala University, BMC P.O. Box 580, SE-751 23, Uppsala, Sweden.
| |
Collapse
|
4
|
Hoffmann W. Trefoil Factor Family (TFF) Peptides and Their Diverse Molecular Functions in Mucus Barrier Protection and More: Changing the Paradigm. Int J Mol Sci 2020; 21:ijms21124535. [PMID: 32630599 PMCID: PMC7350206 DOI: 10.3390/ijms21124535] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/17/2020] [Accepted: 06/19/2020] [Indexed: 02/07/2023] Open
Abstract
Trefoil factor family peptides (TFF1, TFF2, TFF3) are typically co-secreted together with mucins. Tff1 represents a gastric tumor suppressor gene in mice. TFFs are also synthesized in minute amounts in the immune and central nervous systems. In mucous epithelia, they support rapid repair by enhancing cell migration ("restitution") via their weak chemotactic and anti-apoptotic effects. For a long time, as a paradigm, this was considered as their major biological function. Within recent years, the formation of disulfide-linked heterodimers was documented for TFF1 and TFF3, e.g., with gastrokine-2 and IgG Fc binding protein (FCGBP). Furthermore, lectin activities were recognized as enabling binding to a lipopolysaccharide of Helicobacter pylori (TFF1, TFF3) or to a carbohydrate moiety of the mucin MUC6 (TFF2). Only recently, gastric TFF1 was demonstrated to occur predominantly in monomeric forms with an unusual free thiol group. Thus, a new picture emerged, pointing to diverse molecular functions for TFFs. Monomeric TFF1 might protect the gastric mucosa as a scavenger for extracellular reactive oxygen/nitrogen species. Whereas, the TFF2/MUC6 complex stabilizes the inner layer of the gastric mucus. In contrast, the TFF3-FCGBP heterodimer (and also TFF1-FCGBP) are likely part of the innate immune defense of mucous epithelia, preventing the infiltration of microorganisms.
Collapse
Affiliation(s)
- Werner Hoffmann
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
| |
Collapse
|
5
|
Liu F, Fu J, Bergstrom K, Shan X, McDaniel JM, McGee S, Bai X, Chen W, Xia L. Core 1-derived mucin-type O-glycosylation protects against spontaneous gastritis and gastric cancer. J Exp Med 2020; 217:e20182325. [PMID: 31645367 PMCID: PMC7037257 DOI: 10.1084/jem.20182325] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 08/12/2019] [Accepted: 09/17/2019] [Indexed: 12/12/2022] Open
Abstract
Core 1-derived mucin-type O-glycans (O-glycans) are a major component of gastric mucus with an unclear role. To address this, we generated mice lacking gastric epithelial O-glycans (GEC C1galt1-/-). GEC C1galt1-/- mice exhibited spontaneous gastritis that progressed to adenocarcinoma with ∼80% penetrance by 1 yr. GEC C1galt1-/- gastric epithelium exhibited defective expression of a major mucus forming O-glycoprotein Muc5AC relative to WT controls, which was associated with impaired gastric acid homeostasis. Inflammation and tumorigenesis in GEC C1galt1-/- stomach were concurrent with activation of caspases 1 and 11 (Casp1/11)-dependent inflammasome. GEC C1galt1-/- mice genetically lacking Casp1/11 had reduced gastritis and gastric cancer progression. Notably, expression of Tn antigen, a truncated form of O-glycan, and CASP1 activation was associated with tumor progression in gastric cancer patients. These results reveal a critical role of O-glycosylation in gastric homeostasis and the protection of the gastric mucosa from Casp1-mediated gastric inflammation and cancer.
Collapse
Affiliation(s)
- Fei Liu
- Department of Gastroenterology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Jianxin Fu
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Kirk Bergstrom
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Xindi Shan
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - J. Michael McDaniel
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Samuel McGee
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Xia Bai
- Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
- State Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou, China
| | - Weichang Chen
- Department of Gastroenterology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Lijun Xia
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
- Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| |
Collapse
|
6
|
Heuer F, Stürmer R, Heuer J, Kalinski T, Lemke A, Meyer F, Hoffmann W. Different Forms of TFF2, A Lectin of the Human Gastric Mucus Barrier: In Vitro Binding Studies. Int J Mol Sci 2019; 20:ijms20235871. [PMID: 31771101 PMCID: PMC6928932 DOI: 10.3390/ijms20235871] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/13/2019] [Accepted: 11/21/2019] [Indexed: 12/19/2022] Open
Abstract
Trefoil factor family 2 (TFF2) and the mucin MUC6 are co-secreted from human gastric and duodenal glands. TFF2 binds MUC6 as a lectin and is a constituent of the gastric mucus. Herein, we investigated human gastric extracts by FPLC and identified mainly high- but also low-molecular-mass forms of TFF2. From the high-molecular-mass forms, TFF2 can be completely released by boiling in SDS or by harsh denaturing extraction. The low-molecular-mass form representing monomeric TFF2 can be washed out in part from gastric mucosa specimens with buffer. Overlay assays with radioactively labeled TFF2 revealed binding to the mucin MUC6 and not MUC5AC. This binding is modulated by Ca2+ and can be blocked by the lectin GSA-II and the monoclonal antibody HIK1083. TFF2 binding was also inhibited by Me-β-Gal, but not the α anomer. Thus, both the α1,4GlcNAc as well as the juxtaperipheral β-galactoside residues of the characteristic GlcNAcα1→4Galβ1→R moiety of human MUC6 are essential for TFF2 binding. Furthermore, there are major differences in the TFF2 binding characteristics when human is compared with the porcine system. Taken together, TFF2 appears to fulfill an important role in stabilizing the inner insoluble gastric mucus barrier layer, particularly by its binding to the mucin MUC6.
Collapse
Affiliation(s)
- Franziska Heuer
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - René Stürmer
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Jörn Heuer
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Thomas Kalinski
- Institute of Pathology, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany
| | - Antje Lemke
- Institute of Pathology, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany
| | - Frank Meyer
- Department of Surgery, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany
| | - Werner Hoffmann
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
- Correspondence:
| |
Collapse
|
7
|
Cortés A, Mikeš L, Muñoz-Antolí C, Álvarez-Izquierdo M, Esteban JG, Horák P, Toledo R. Secreted cathepsin L-like peptidases are involved in the degradation of trapped antibodies on the surface of Echinostoma caproni. Parasitol Res 2019; 118:3377-3386. [PMID: 31720841 DOI: 10.1007/s00436-019-06487-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/25/2019] [Indexed: 12/11/2022]
Abstract
Antibody trapping is a recently described strategy for immune evasion observed in the intestinal trematode Echinostoma caproni, which may aid to avoiding the host humoral response, thus facilitating parasite survival in the presence of high levels of local-specific antibodies. Parasite-derived peptidases carry out the degradation of trapped antibodies, being essential for this mechanism. Herein, we show that cathepsin-like cysteine endopeptidases are active in the excretory/secretory products (ESPs) of E. caproni and play an important role in the context of antibody trapping. Cysteine endopeptidase activity was detected in the ESPs of E. caproni adults. The affinity probe DCG-04 distinguished a cysteine peptidase band in ESPs, which was specifically recognized by an anti-cathepsin L heterologous antibody. The same antibody localized this protein in the gut and syncytial tegument of adult worms. Studies with cultured parasites showed that in vivo-bound antibodies are removed from the parasite surface in the absence of peptidase inhibitors, while addition of cathepsin L inhibitor prevented their degradation. These results indicate that cathepsin L-like peptidases are involved in the degradation of surface-trapped antibodies and suggest that cysteine peptidases are not only crucial for tissue-invading trematodes, but they can be equally relevant at the parasite-host interface in gut-dwelling flukes.
Collapse
Affiliation(s)
- Alba Cortés
- Área de Parasitología, Departamento de Farmacia y Tecnología Farmacéutica y Parasitología, Facultad de Farmacia, Universitat de València, Avda. Vicent Andrés Estellés s/n, 46100, Burjassot, Valencia, Spain
| | - Libor Mikeš
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Carla Muñoz-Antolí
- Área de Parasitología, Departamento de Farmacia y Tecnología Farmacéutica y Parasitología, Facultad de Farmacia, Universitat de València, Avda. Vicent Andrés Estellés s/n, 46100, Burjassot, Valencia, Spain
| | - María Álvarez-Izquierdo
- Área de Parasitología, Departamento de Farmacia y Tecnología Farmacéutica y Parasitología, Facultad de Farmacia, Universitat de València, Avda. Vicent Andrés Estellés s/n, 46100, Burjassot, Valencia, Spain
| | - J Guillermo Esteban
- Área de Parasitología, Departamento de Farmacia y Tecnología Farmacéutica y Parasitología, Facultad de Farmacia, Universitat de València, Avda. Vicent Andrés Estellés s/n, 46100, Burjassot, Valencia, Spain
| | - Petr Horák
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Rafael Toledo
- Área de Parasitología, Departamento de Farmacia y Tecnología Farmacéutica y Parasitología, Facultad de Farmacia, Universitat de València, Avda. Vicent Andrés Estellés s/n, 46100, Burjassot, Valencia, Spain.
| |
Collapse
|
8
|
Testerman TL, Semino-Mora C, Cann JA, Qiang B, Peña EA, Liu H, Olsen CH, Chen H, Appt SE, Kaplan JR, Register TC, Merrell DS, Dubois A. Both diet and Helicobacter pylori infection contribute to atherosclerosis in pre- and postmenopausal cynomolgus monkeys. PLoS One 2019; 14:e0222001. [PMID: 31490998 PMCID: PMC6730863 DOI: 10.1371/journal.pone.0222001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 08/20/2019] [Indexed: 02/07/2023] Open
Abstract
A number of viruses and bacterial species have been implicated as contributors to atherosclerosis, potentially providing novel pathways for prevention. Epidemiological studies examining the association between Helicobacter pylori and cardiovascular disease have yielded variable results and no studies have been conducted in nonhuman primates. In this investigation, we examined the relationship between H. pylori infection and atherosclerosis development in socially housed, pre- and postmenopausal cynomolgus macaques consuming human-like diets. Ninety-four premenopausal cynomolgus monkeys (Macaca fascicularis) were fed for 36 months an atherogenic diet deriving its protein from either casein lactalbumin(CL) or high isoflavone soy (SOY). Animals were then ovariectomized and fed either the same or the alternate diet for an additional 36 months. Iliac artery biopsies were obtained at the time of ovariectomy and iliac and coronary artery sections were examined at the end of the study. Evidence of H. pylori infection was found in 64% of the monkeys and 46% of animals had live H. pylori within coronary atheromas as determined by mRNA-specific in situ hybridization. There was a significant linear relationship between the densities of gastric and atheroma organisms. Helicobactor pylori infection correlated with increased intimal plaque area and thickness at both the premenopausal and postmenopausal time points and regardless of diet (p< 0.01), although animals consuming the SOY diet throughout had the least amount of atherosclerosis. Additionally, plasma lipid profiles, intimal collagen accumulation, ICAM-1, and plaque macrophage densities were adversely affected by H. pylori infection among animals consuming the CL diet, while the SOY diet had the opposite effect. Plaque measurements were more highly associated with the densities of cagA-positive H. pylori within coronary atheromas than with the densities of gastric organisms, whereas plasma lipid changes were associated with H. pylori infection, but not cagA status. This study provides strong evidence that live H. pylori infects atheromas, exacerbates atherosclerotic plaque development, and alters plasma lipid profiles independently of diet or hormonal status. Finally, socially subordinate animals relative to their dominant counterparts had a greater prevalence of H. pylori, suggesting a stress effect. The results indicate that early H. pylori eradication could prevent or delay development of cardiovascular disease.
Collapse
Affiliation(s)
- Traci L. Testerman
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, United States of America
| | - Cristina Semino-Mora
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
| | | | - Beidi Qiang
- Department of Mathematics and Statistics, Southern Illinois University at Edwardsville, Edwardsville, IL, United States of America
| | - Edsel A. Peña
- Department of Statistics, University of South Carolina, Columbia, SC, United States of America
| | - Hui Liu
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
| | - Cara H. Olsen
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
| | - Haiying Chen
- Wake Forest University Primate Center, Wake Forest University School of Medicine, Winston-Salem, NC, United States of America
| | - Susan E. Appt
- Wake Forest University Primate Center, Wake Forest University School of Medicine, Winston-Salem, NC, United States of America
| | - Jay R. Kaplan
- Wake Forest University Primate Center, Wake Forest University School of Medicine, Winston-Salem, NC, United States of America
| | - Thomas C. Register
- Wake Forest University Primate Center, Wake Forest University School of Medicine, Winston-Salem, NC, United States of America
| | - D. Scott Merrell
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
| | - Andre Dubois
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
| |
Collapse
|
9
|
Ni X, Tan Z, Ding C, Zhang C, Song L, Yang S, Liu M, Jia R, Zhao C, Song L, Liu W, Zhou Q, Gong T, Li X, Tai Y, Zhu W, Shi T, Wang Y, Xu J, Zhen B, Qin J. A region-resolved mucosa proteome of the human stomach. Nat Commun 2019; 10:39. [PMID: 30604760 PMCID: PMC6318339 DOI: 10.1038/s41467-018-07960-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 12/06/2018] [Indexed: 12/13/2022] Open
Abstract
The human gastric mucosa is the most active layer of the stomach wall, involved in food digestion, metabolic processes and gastric carcinogenesis. Anatomically, the human stomach is divided into seven regions, but the protein basis for cellular specialization is not well understood. Here we present a global analysis of protein profiles of 82 apparently normal mucosa samples obtained from living individuals by endoscopic stomach biopsy. We identify 6,258 high-confidence proteins and estimate the ranges of protein expression in the seven stomach regions, presenting a region-resolved proteome reference map of the near normal, human stomach. Furthermore, we measure mucosa protein profiles of tumor and tumor nearby tissues (TNT) from 58 gastric cancer patients, enabling comparisons between tumor, TNT, and normal tissue. These datasets provide a rich resource for the gastrointestinal tract research community to investigate the molecular basis for region-specific functions in mucosa physiology and pathology including gastric cancer. The human stomach is divided into seven anatomically distinct regions but their protein composition is largely unknown. Here, the authors present a region-resolved map of the healthy human stomach mucosa as well as mucosa proteomes of tumor and tumor nearby tissue from gastric cancer patients.
Collapse
Affiliation(s)
- Xiaotian Ni
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China.,State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China.,Center for Bioinformatics, East China Normal University, Shanghai, 200241, China
| | - Zhaoli Tan
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China
| | - Chen Ding
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China.,State Key Laboratory of Genetic Engineering, Human Phenome Institute, Institutes of Biomedical Sciences, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Chunchao Zhang
- Alkek Center for Molecular Discovery, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Lan Song
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China.,Department of Bioinformatics, College of Life Science, Hebei University, Baoding, 071002, China
| | - Shuai Yang
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China
| | - Mingwei Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Ru Jia
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China
| | - Chuanhua Zhao
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China
| | - Lei Song
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Wanlin Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Quan Zhou
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Tongqing Gong
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Xianju Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Yanhong Tai
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China
| | - Weimin Zhu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China
| | - Tieliu Shi
- Center for Bioinformatics, East China Normal University, Shanghai, 200241, China
| | - Yi Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China.,Alkek Center for Molecular Discovery, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jianming Xu
- Department of Gastrointestinal Oncology, The Fifth Medical Center, General Hospital of PLA, Beijing, 100071, China.
| | - Bei Zhen
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China.
| | - Jun Qin
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (The PHOENIX Center, Beijing), Institute of lifeomics, Beijing, 102206, China. .,State Key Laboratory of Genetic Engineering, Human Phenome Institute, Institutes of Biomedical Sciences, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, 200032, China. .,Alkek Center for Molecular Discovery, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
| |
Collapse
|
10
|
Li T, Liu X, Riederer B, Nikolovska K, Singh AK, Mäkelä KA, Seidler A, Liu Y, Gros G, Bartels H, Herzig KH, Seidler U. Genetic ablation of carbonic anhydrase IX disrupts gastric barrier function via claudin-18 downregulation and acid backflux. Acta Physiol (Oxf) 2018; 222:e12923. [PMID: 28748627 PMCID: PMC5901031 DOI: 10.1111/apha.12923] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 11/21/2016] [Accepted: 07/24/2017] [Indexed: 12/28/2022]
Abstract
Aim This study aimed to explore the molecular mechanisms for the parietal cell loss and fundic hyperplasia observed in gastric mucosa of mice lacking the carbonic anhydrase 9 (CAIX). Methods We assessed the ability of CAIX‐knockout and WT gastric surface epithelial cells to withstand a luminal acid load by measuring the pHi of exteriorized gastric mucosa in vivo using two‐photon confocal laser scanning microscopy. Cytokines and claudin‐18A2 expression was analysed by RT‐PCR. Results CAIX‐knockout gastric surface epithelial cells showed significantly faster pHi decline after luminal acid load compared to WT. Increased gastric mucosal IL‐1β and iNOS, but decreased claudin‐18A2 expression (which confer acid resistance) was observed shortly after weaning, prior to the loss of parietal and chief cells. At birth, neither inflammatory cytokines nor claudin‐18 expression were altered between CAIX and WT gastric mucosa. The gradual loss of acid secretory capacity was paralleled by an increase in serum gastrin, IL‐11 and foveolar hyperplasia. Mild chronic proton pump inhibition from the time of weaning did not prevent the claudin‐18 decrease nor the increase in inflammatory markers at 1 month of age, except for IL‐1β. However, the treatment reduced the parietal cell loss in CAIX‐KO mice in the subsequent months. Conclusions We propose that CAIX converts protons that either backflux or are extruded from the cells rapidly to CO2 and H2O, contributing to tight junction protection and gastric epithelial pHi regulation. Lack of CAIX results in persistent acid backflux via claudin‐18 downregulation, causing loss of parietal cells, hypergastrinaemia and foveolar hyperplasia.
Collapse
Affiliation(s)
- T. Li
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - X. Liu
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
- Department of Department of Gastroenterology; Affiliated Hospital of Zunyi Medical College; Zunyi China
| | - B. Riederer
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - K. Nikolovska
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - A. K. Singh
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - K. A. Mäkelä
- Institute of Biomedicine and Biocenter of Oulu; Oulu University; Finland
| | - A. Seidler
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - Y. Liu
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| | - G. Gros
- Department of Physiology; Hannover Medical School; Hannover Germany
| | - H. Bartels
- Department of Anatomy; Hannover Medical School; Hannover Germany
| | - K. H. Herzig
- Institute of Biomedicine and Biocenter of Oulu; Oulu University; Finland
| | - U. Seidler
- Department of Gastroenterology; Hannover Medical School; Hannover Germany
| |
Collapse
|
11
|
Demouveaux B, Gouyer V, Gottrand F, Narita T, Desseyn JL. Gel-forming mucin interactome drives mucus viscoelasticity. Adv Colloid Interface Sci 2018; 252:69-82. [PMID: 29329667 DOI: 10.1016/j.cis.2017.12.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 12/31/2022]
Abstract
Mucus is a hydrogel that constitutes the first innate defense in all mammals. The main organic component of mucus, gel-forming mucins, forms a complex network through both reversible and irreversible interactions that drive mucus gel formation. Significant advances in the understanding of irreversible gel-forming mucins assembly have been made using recombinant protein approaches. However, little is known about the reversible interactions that may finely modulate mucus viscoelasticity, which can be characterized using rheology. This approach can be used to investigate both the nature of gel-forming mucins interactions and factors that influence hydrogel formation. This knowledge is directly relevant to the development of new drugs to modulate mucus viscoelasticity and to restore normal mucus functions in diseases such as in cystic fibrosis. The aim of the present review is to summarize the current knowledge about the relationship between the mucus protein matrix and its functions, with emphasis on mucus viscoelasticity.
Collapse
Affiliation(s)
| | - Valérie Gouyer
- Univ. Lille, Inserm, CHU Lille, LIRIC UMR 995, F-59000 Lille, France
| | - Frédéric Gottrand
- Univ. Lille, Inserm, CHU Lille, LIRIC UMR 995, F-59000 Lille, France
| | - Tetsuharu Narita
- Laboratoire Sciences et Ingénierie de la Matière Molle, PSL Research University, UPMC Univ Paris 06, ESPCI Paris, CNRS, 10 rue Vauquelin, 75231 Paris Cedex 05, France; Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Japan
| | - Jean-Luc Desseyn
- Univ. Lille, Inserm, CHU Lille, LIRIC UMR 995, F-59000 Lille, France.
| |
Collapse
|
12
|
Murgia X, Loretz B, Hartwig O, Hittinger M, Lehr CM. The role of mucus on drug transport and its potential to affect therapeutic outcomes. Adv Drug Deliv Rev 2018; 124:82-97. [PMID: 29106910 DOI: 10.1016/j.addr.2017.10.009] [Citation(s) in RCA: 180] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/29/2017] [Accepted: 10/17/2017] [Indexed: 12/16/2022]
Abstract
A layer of mucus covers the surface of all wet epithelia throughout the human body. Mucus is a hydrogel mainly composed of water, mucins (glycoproteins), DNA, proteins, lipids, and cell debris. This complex composition yields a tenacious viscoelastic hydrogel that lubricates and protects the exposed epithelia from external threats and enzymatic degradation. The natural protective role of mucus is nowadays acknowledged as a major barrier to be overcome in non-invasive drug delivery. The heterogeneity of mucus components offers a wide range of potential chemical interaction sites for macromolecules, while the mesh-like architecture given to mucus by the intermolecular cross-linking of mucin molecules results in a dense network that physically, and in a size-dependent manner, hinders the diffusion of nanoparticles through mucus. Consequently, drug diffusion, epithelial absorption, drug bioavailability, and ultimately therapeutic outcomes of mucosal drug delivery can be attenuated.
Collapse
Affiliation(s)
- Xabier Murgia
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, 66123 Saarbrücken, Germany
| | - Brigitta Loretz
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, 66123 Saarbrücken, Germany
| | - Olga Hartwig
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, 66123 Saarbrücken, Germany
| | - Marius Hittinger
- PharmBioTec GmbH, Science Park 1 Campus D 1.1, 66123 Saarbrücken, Germany
| | - Claus-Michael Lehr
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, 66123 Saarbrücken, Germany; PharmBioTec GmbH, Science Park 1 Campus D 1.1, 66123 Saarbrücken, Germany; Department of Pharmacy, Saarland University, 66123 Saarbrücken, Germany.
| |
Collapse
|
13
|
He J, Yang X, Guo Y, Zhang F, Wan H, Sun X, Tuo B, Dong H. Ca 2+ signaling in HCO 3- secretion and protection of upper GI tract. Oncotarget 2017; 8:102681-102689. [PMID: 29254280 PMCID: PMC5731990 DOI: 10.18632/oncotarget.21840] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 09/23/2017] [Indexed: 01/05/2023] Open
Abstract
The cytosolic calcium ([Ca2+]cyt) is one of the most important cell signaling that can modulate gastrointestinal (GI) epithelial secretion and promote GI mucosal wound repair. The GI mucosal bicarbonate secretion is the main mechanism of mucosal protection. Our research team has been working in this field and provided solid evidence for the important role of Ca2+ signaling in the regulation of GI epithelial secretion and the underlying molecular mechanisms. In this review, we attempt to systemically review the current status of our knowledge on the role of Ca2+ signaling in the regulation of intestinal bicarbonate secretion and in the upper GI epithelial protection. We expect that novel targets could be identified for drug development to better protect GI mucosa and treat mucosal injury with the advance in this filed.
Collapse
Affiliation(s)
- Jialin He
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, Zunyi, China
| | - Xin Yang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Yanjun Guo
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Fenglian Zhang
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Hanxing Wan
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Xuemei Sun
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, Zunyi, China
| | - Hui Dong
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, Zunyi, China.,Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| |
Collapse
|
14
|
Zolotarev VA, Andreeva YV, Vershinina E, Khropycheva RP. Interaction of Constitutive Nitric Oxide Synthases with Cyclooxygenases in Regulation of Bicarbonate Secretion in the Gastric Mucosa. Bull Exp Biol Med 2017; 163:6-9. [DOI: 10.1007/s10517-017-3724-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Indexed: 10/19/2022]
|
15
|
Granger DN, Holm L, Kvietys P. The Gastrointestinal Circulation: Physiology and Pathophysiology. Compr Physiol 2016; 5:1541-83. [PMID: 26140727 DOI: 10.1002/cphy.c150007] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The gastrointestinal (GI) circulation receives a large fraction of cardiac output and this increases following ingestion of a meal. While blood flow regulation is not the intense phenomenon noted in other vascular beds, the combined responses of blood flow, and capillary oxygen exchange help ensure a level of tissue oxygenation that is commensurate with organ metabolism and function. This is evidenced in the vascular responses of the stomach to increased acid production and in intestine during periods of enhanced nutrient absorption. Complimenting the metabolic vasoregulation is a strong myogenic response that contributes to basal vascular tone and to the responses elicited by changes in intravascular pressure. The GI circulation also contributes to a mucosal defense mechanism that protects against excessive damage to the epithelial lining following ingestion of toxins and/or noxious agents. Profound reductions in GI blood flow are evidenced in certain physiological (strenuous exercise) and pathological (hemorrhage) conditions, while some disease states (e.g., chronic portal hypertension) are associated with a hyperdynamic circulation. The sacrificial nature of GI blood flow is essential for ensuring adequate perfusion of vital organs during periods of whole body stress. The restoration of blood flow (reperfusion) to GI organs following ischemia elicits an exaggerated tissue injury response that reflects the potential of this organ system to generate reactive oxygen species and to mount an inflammatory response. Human and animal studies of inflammatory bowel disease have also revealed a contribution of the vasculature to the initiation and perpetuation of the tissue inflammation and associated injury response.
Collapse
Affiliation(s)
- D Neil Granger
- Department of Molecular and Cellular Physiology, LSU Health Science Center-Shreveport, Shreveport, Louisiana, USA
| | - Lena Holm
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Peter Kvietys
- Department of Physiological Sciences, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| |
Collapse
|
16
|
Petersson J, Jädert C, Phillipson M, Borniquel S, Lundberg JO, Holm L. Physiological recycling of endogenous nitrate by oral bacteria regulates gastric mucus thickness. Free Radic Biol Med 2015; 89:241-7. [PMID: 26163002 DOI: 10.1016/j.freeradbiomed.2015.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 06/30/2015] [Accepted: 07/01/2015] [Indexed: 02/08/2023]
Abstract
BACKGROUND Inorganic nitrate from exogenous and endogenous sources is accumulated in saliva, reduced to nitrite by oral bacteria and further converted to nitric oxide (NO) and other bioactive nitrogen oxides in the acidic gastric lumen. To further explore the role of oral microbiota in this process we examined the gastric mucus layer in germ free (GF) and conventional mice given different doses of nitrate and nitrite. METHODS Mice were given either nitrate (100mg/kg/d) or nitrite (0.55-11 mg/kg/d) in the drinking water for 7 days, with the lowest nitrite dose resembling the levels provided by swallowing of fasting saliva. The gastric mucus layer was measured in vivo. RESULTS GF animals were almost devoid of the firmly adherent mucus layer compared to conventional mice. Dietary nitrate increased the mucus thickness in conventional animals but had no effect in GF mice. In contrast, nitrite at all doses, restored the mucus thickness in GF mice to the same levels as in conventional animals. The nitrite-mediated increase in gastric mucus thickness was not inhibited by the soluble guanylyl cyclase inhibitor ODQ. Mice treated with antibiotics had significantly thinner mucus than controls. Additional studies on mucin gene expression demonstrated down regulation of Muc5ac and Muc6 in germ free mice after nitrite treatment. CONCLUSION Oral bacteria remotely modulate gastric mucus generation via bioactivation of salivary nitrate. In the absence of a dietary nitrate intake, salivary nitrate originates mainly from NO synthase. Thus, oxidized NO from the endothelium and elsewhere is recycled to regulate gastric mucus homeostasis.
Collapse
Affiliation(s)
- Joel Petersson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Cecilia Jädert
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Mia Phillipson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Sara Borniquel
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Jon O Lundberg
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
| | - Lena Holm
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden.
| |
Collapse
|
17
|
Hage N, Howard T, Phillips C, Brassington C, Overman R, Debreczeni J, Gellert P, Stolnik S, Winkler GS, Falcone FH. Structural basis of Lewis(b) antigen binding by the Helicobacter pylori adhesin BabA. SCIENCE ADVANCES 2015; 1:e1500315. [PMID: 26601230 PMCID: PMC4643811 DOI: 10.1126/sciadv.1500315] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 05/03/2015] [Indexed: 05/09/2023]
Abstract
Helicobacter pylori is a leading cause of peptic ulceration and gastric cancer worldwide. To achieve colonization of the stomach, this Gram-negative bacterium adheres to Lewis(b) (Le(b)) antigens in the gastric mucosa using its outer membrane protein BabA. Structural information for BabA has been elusive, and thus, its molecular mechanism for recognizing Le(b) antigens remains unknown. We present the crystal structure of the extracellular domain of BabA, from H. pylori strain J99, in the absence and presence of Le(b) at 2.0- and 2.1-Å resolutions, respectively. BabA is a predominantly α-helical molecule with a markedly kinked tertiary structure containing a single, shallow Le(b) binding site at its tip within a β-strand motif. No conformational change occurs in BabA upon binding of Le(b), which is characterized by low affinity under acidic [K D (dissociation constant) of ~227 μM] and neutral (K D of ~252 μM) conditions. Binding is mediated by a network of hydrogen bonds between Le(b) Fuc1, GlcNAc3, Fuc4, and Gal5 residues and a total of eight BabA amino acids (C189, G191, N194, N206, D233, S234, S244, and T246) through both carbonyl backbone and side-chain interactions. The structural model was validated through the generation of two BabA variants containing N206A and combined D233A/S244A substitutions, which result in a reduction and complete loss of binding affinity to Le(b), respectively. Knowledge of the molecular basis of Le(b) recognition by BabA provides a platform for the development of therapeutics targeted at inhibiting H. pylori adherence to the gastric mucosa.
Collapse
Affiliation(s)
- Naim Hage
- School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Tina Howard
- Discovery Sciences, Innovative Medicines and Early Development, AstraZeneca R&D, Alderley Park, Cheshire SK10 4TG, UK
- Corresponding author. E-mail: (T.H.); (F.H.F.)
| | - Chris Phillips
- Discovery Sciences, Innovative Medicines and Early Development, AstraZeneca R&D, Darwin Building, 310 Cambridge Science Park, Milton Road, Cambridge CB4 0WG, UK
| | - Claire Brassington
- Discovery Sciences, Innovative Medicines and Early Development, AstraZeneca R&D, Alderley Park, Cheshire SK10 4TG, UK
| | - Ross Overman
- Discovery Sciences, Innovative Medicines and Early Development, AstraZeneca R&D, Alderley Park, Cheshire SK10 4TG, UK
| | - Judit Debreczeni
- Discovery Sciences, Innovative Medicines and Early Development, AstraZeneca R&D, Darwin Building, 310 Cambridge Science Park, Milton Road, Cambridge CB4 0WG, UK
| | - Paul Gellert
- Pharmaceutical Development, AstraZeneca R&D, Charter Way, Macclesfield, Cheshire SK10 2NA, UK
| | - Snow Stolnik
- School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - G. Sebastiaan Winkler
- School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Franco H. Falcone
- School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
- Corresponding author. E-mail: (T.H.); (F.H.F.)
| |
Collapse
|
18
|
Hoffmann W. TFF2, a MUC6-binding lectin stabilizing the gastric mucus barrier and more (Review). Int J Oncol 2015. [PMID: 26201258 DOI: 10.3892/ijo.2015.3090] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The peptide TFF2 (formerly 'spasmolytic polypeptide'), a member of the trefoil factor family (TFF) containing two TFF domains, is mainly expressed together with the mucin MUC6 in the gastric epithelium and duodenal Brunner's glands. Pathologically, TFF2 expression is observed ectopically during stone diseases, chronic inflammatory conditions and in several metaplastic and neoplastic epithelia; most prominent being the 'spasmolytic polypeptide-expressing metaplasia' (SPEM), which is an established gastric precancerous lesion. TFF2 plays a critical role in maintaining gastric mucosal integrity and appears to restrain tumorigenesis in the stomach. Recently, porcine TFF2 has been shown to interact with the gastric mucin MUC6 and thus stabilize the gastric mucus barrier. On the one hand, TFF2 binds to MUC6 via non-covalent lectin interactions with the glycotope GlcNAcα1→4Galβ1→R. On the other hand, TFF2 is probably also covalently bound to MUC6 via disulfide bridges. Thus, implications for the complex multimeric assembly, cross-linking, and packaging of MUC6 as well as the rheology of gastric mucus are discussed in detail in this review. Furthermore, TFF2 is also expressed in minor amounts in the immune and nervous systems. Thus, similar to galectins, its lectin activity would perfectly enable TFF2 to form multivalent complexes and cross-linked lattices with a plethora of transmembrane glycoproteins and thus modulate different signal transduction processes. This could explain the multiple and diverse biological effects of TFF2 [e.g., motogenic, (anti)apoptotic, and angiogenic effects]. Finally, a function during fertilization is also possible for TFF domains because they occur as shuffled modules in certain zona pellucida proteins.
Collapse
Affiliation(s)
- Werner Hoffmann
- Institute of Molecular Biology and Medicinal Chemistry, Otto-von-Guericke-University Magdeburg, D-39120 Magdeburg, Germany
| |
Collapse
|
19
|
Song JL, Zhou Y, Feng X, Zhao X. White tea (Camellia sinenesis (L.)) ethanol extracts attenuate reserpine-induced gastric ulcers in mice. Food Sci Biotechnol 2015. [DOI: 10.1007/s10068-015-0148-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
|
20
|
Song JL, Sun P, Wang R, Zhao X. Gastroprotective Effects of Methanolic Extract of Sterculia nobilis Smith Seeds in Reserpine-Induced Gastric Ulcer in Mice. J Food Biochem 2015. [DOI: 10.1111/jfbc.12125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jia-Le Song
- Department of Nutrition and Food Hygiene; School of Public Health; Guilin Medical University; Guilin Guangxi 541004 China
- Department of Food Science and Nutrition; Pusan National University; Busan 609-735 South Korea
- Institute of Functional Ecological Food; Chongqing University of Education; 9 Xuefu Main Street Nan'an District Chongqing 400067 China
| | - Peng Sun
- Institute of Functional Ecological Food; Chongqing University of Education; 9 Xuefu Main Street Nan'an District Chongqing 400067 China
- Department of Biological and Chemical Engineering; Chongqing University of Education; 9 Xuefu Main Street Nan'an District Chongqing 400067 China
| | - Rui Wang
- Institute of Functional Ecological Food; Chongqing University of Education; 9 Xuefu Main Street Nan'an District Chongqing 400067 China
- Department of Biological and Chemical Engineering; Chongqing University of Education; 9 Xuefu Main Street Nan'an District Chongqing 400067 China
| | - Xin Zhao
- Institute of Functional Ecological Food; Chongqing University of Education; 9 Xuefu Main Street Nan'an District Chongqing 400067 China
- Department of Biological and Chemical Engineering; Chongqing University of Education; 9 Xuefu Main Street Nan'an District Chongqing 400067 China
| |
Collapse
|
21
|
Wang J, Barbuskaite D, Tozzi M, Giannuzzo A, Sørensen CE, Novak I. Proton Pump Inhibitors Inhibit Pancreatic Secretion: Role of Gastric and Non-Gastric H+/K+-ATPases. PLoS One 2015; 10:e0126432. [PMID: 25993003 PMCID: PMC4436373 DOI: 10.1371/journal.pone.0126432] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 04/02/2015] [Indexed: 02/07/2023] Open
Abstract
The mechanism by which pancreas secretes high HCO3- has not been fully resolved. This alkaline secretion, formed in pancreatic ducts, can be achieved by transporting HCO3- from serosa to mucosa or by moving H+ in the opposite direction. The aim of the present study was to determine whether H+/K+-ATPases are expressed and functional in human pancreatic ducts and whether proton pump inhibitors (PPIs) have effect on those. Here we show that the gastric HKα1 and HKβ subunits (ATP4A; ATP4B) and non-gastric HKα2 subunits (ATP12A) of H+/K+-ATPases are expressed in human pancreatic cells. Pumps have similar localizations in duct cell monolayers (Capan-1) and human pancreas, and notably the gastric pumps are localized on the luminal membranes. In Capan-1 cells, PPIs inhibited recovery of intracellular pH from acidosis. Furthermore, in rats treated with PPIs, pancreatic secretion was inhibited but concentrations of major ions in secretion follow similar excretory curves in control and PPI treated animals. In addition to HCO3-, pancreas also secretes K+. In conclusion, this study calls for a revision of the basic model for HCO3- secretion. We propose that proton transport is driving secretion, and that in addition it may provide a protective pH buffer zone and K+ recirculation. Furthermore, it seems relevant to re-evaluate whether PPIs should be used in treatment therapies where pancreatic functions are already compromised.
Collapse
Affiliation(s)
- Jing Wang
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Dagne Barbuskaite
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Marco Tozzi
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Andrea Giannuzzo
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Christiane E. Sørensen
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Ivana Novak
- Department of Biology, Section for Molecular Integrative Physiology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
| |
Collapse
|
22
|
Bardou M, Quenot JP, Barkun A. Stress-related mucosal disease in the critically ill patient. Nat Rev Gastroenterol Hepatol 2015; 12:98-107. [PMID: 25560847 DOI: 10.1038/nrgastro.2014.235] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Bleeding from stress-related mucosal disease in critically ill patients remains an important clinical management issue. Although only a small proportion (1-6%) of patients admitted to an intensive care unit (ICU) will bleed, a substantial proportion exhibit clinical risk factors (mechanical ventilation for >48 h and a coagulopathy) that predict an increased risk of bleeding. Furthermore, upper gastrointestinal mucosal lesions can be found in 75-100% of patients in ICUs. Although uncommon, stress-ulcer bleeding is a severe complication with an estimated mortality of 40-50%, mostly from decompensating an underlying condition or multiorgan failure. Although the vast majority of patients in ICUs receive stress-ulcer prophylaxis, largely with PPIs, some controversy surrounds their efficacy and safety. Indeed, no single trial has shown that stress-ulcer prophylaxis reduces mortality. Some reports suggest that the use of PPIs increases the risk of nosocomial infections. However, several meta-analyses and cost-effectiveness studies suggest PPIs to be more clinically effective and cost-effective than histamine-2 receptor antagonists, without considerable increases in nosocomial pneumonia. To help clinicians use the most appropriate strategy for treatment of patients in the ICU, this Review presents the latest information on all aspects of stress-related mucosal disease.
Collapse
Affiliation(s)
- Marc Bardou
- Gastroenterology and Hepatology Department, CHU de Dijon, France, 14 Rue Gaffarel BP77908, 21079 Dijon Cedex, France
| | - Jean-Pierre Quenot
- Medical Intensive Care Unit, CHU de Dijon, France, 14 Rue Gaffarel BP77908, 21079 Dijon Cedex, France
| | - Alan Barkun
- Gastroenterology Department, McGill University Health Centre, Montreal General Hospital Site, Room D7-346, 1650 Cedar Avenue, Montréal, QC H3G 1A4, Canada
| |
Collapse
|
23
|
Pereira C, Barbosa RM, Laranjinha J. Dietary nitrite induces nitrosation of the gastric mucosa: the protective action of the mucus and the modulatory effect of red wine. J Nutr Biochem 2015; 26:476-83. [PMID: 25701398 DOI: 10.1016/j.jnutbio.2014.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 12/01/2014] [Accepted: 12/02/2014] [Indexed: 12/13/2022]
Abstract
The stomach chemical environment promotes the production of new molecules that can induce post-translational modifications of endogenous proteins with physiological impact. The nitrate-nitrite-nitric oxide pathway is relevant in this process via production of nitric oxide ((•)NO) and nitric oxide-derived nitrogen oxides (NOx) at high concentrations. Using a highly sensitive and selective chemiluminescence approach, we found that exposure the stomach of rats to nitrite yielded S- and N-nitroso derivatives in gastric mucus cysteine-rich glycoproteins (mucins). To lesser extent, the underlying epithelial cell layers also suffered nitrite-driven S- and N-nitroso modifications which increased upon mucus removal, indicating that, under normal nitrite load, (•)NO and NOx can reach inner layers of the stomach wall and locally modify proteins. S-nitrosation was by large the predominant modification. In vitro and ex vivo experiments indicated that the gastric nitrosation pattern is triggered by dietary nitrite in a concentration dependent manner, encompassing the intermediary formation of (•)NO and is susceptible to modulation by dietary reductants, notably red wine polyphenols. Collectively, these results suggest a protective action of the mucus and potential (•)NO-dependent biochemical effects at deeper cells layers of the mucosa.
Collapse
Affiliation(s)
- Cassilda Pereira
- Center for Neuroscience and Cell Biology and Faculty of Pharmacy, University of Coimbra, 3000 Coimbra, Portugal
| | - Rui M Barbosa
- Center for Neuroscience and Cell Biology and Faculty of Pharmacy, University of Coimbra, 3000 Coimbra, Portugal
| | - João Laranjinha
- Center for Neuroscience and Cell Biology and Faculty of Pharmacy, University of Coimbra, 3000 Coimbra, Portugal.
| |
Collapse
|
24
|
Aihara E, Montrose MH. Importance of Ca(2+) in gastric epithelial restitution-new views revealed by real-time in vivo measurements. Curr Opin Pharmacol 2014; 19:76-83. [PMID: 25108560 DOI: 10.1016/j.coph.2014.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/22/2014] [Accepted: 07/22/2014] [Indexed: 12/14/2022]
Abstract
It has been a few decades since Ca(2+) was identified as one of the important factors that can accelerate gastric wound repair as well as contribute to epithelial homeostasis and regulation of gastric secretions. The mechanistic basis has remained largely unexplored in vivo because it was not possible to track in real time either intracellular Ca(2+) mobilization or wound repair in living tissues. Recent advances in technology, such as combining high resolution light microscopy and genetically encoded Ca(2+) reporters in mice, now allow the monitoring of Ca(2+) mobilization during gastric epithelial cell restitution. Ca(2+) is a ubiquitous second messenger that influences numerous cellular processes, including gastric acid/bicarbonate secretion, mucus secretion, and cell migration. We have demonstrated that cytosolic Ca(2+) mobilization within the restituting gastric epithelial cells is a central signal driving small wound repair. However, extracellular Ca(2+) is also mobilized in the juxtamucosal luminal space above a wound, and evidence suggests extracellular Ca(2+) is a third messenger that also promotes gastric epithelial restitution. Interplay between intracellular and extracellular Ca(2+) is necessary for efficient gastric epithelial restitution.
Collapse
Affiliation(s)
- Eitaro Aihara
- Department of Molecular and Cellular Physiology, University of Cincinnati, OH 45267, USA
| | - Marshall H Montrose
- Department of Molecular and Cellular Physiology, University of Cincinnati, OH 45267, USA.
| |
Collapse
|
25
|
Gastrointestinal HCO3- transport and epithelial protection in the gut: new techniques, transport pathways and regulatory pathways. Curr Opin Pharmacol 2013; 13:900-8. [PMID: 24280619 DOI: 10.1016/j.coph.2013.10.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 09/29/2013] [Accepted: 10/01/2013] [Indexed: 02/07/2023]
Abstract
The concept of a protective alkaline gastric and duodenal mucus layer is a century old, yet it is amazing how much new information on HCO3(-) transport pathways has emerged recently, made possible by the extensive utilization of gene-deleted and transgenic mice and novel techniques to study HCO3(-) transport. This review highlights recent findings regarding the importance of HCO3(-) for mucosal protection of duodenum and other gastrointestinal epithelia against luminal acid and other damaging factors. Recently, methods have been developed to visualize HCO3(-) transport in vivo by assessing the surface pH in the mucus layer, as well as the epithelial pH. New information about HCO3(-) transport pathways, and emerging concepts about the intricate regulatory network that governs duodenal HCO3(-) secretion are described, and new perspectives for drug therapy discussed.
Collapse
|
26
|
Yang I, Nell S, Suerbaum S. Survival in hostile territory: the microbiota of the stomach. FEMS Microbiol Rev 2013; 37:736-61. [DOI: 10.1111/1574-6976.12027] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 05/28/2013] [Accepted: 06/07/2013] [Indexed: 02/06/2023] Open
|
27
|
Ermund A, Schütte A, Johansson MEV, Gustafsson JK, Hansson GC. Studies of mucus in mouse stomach, small intestine, and colon. I. Gastrointestinal mucus layers have different properties depending on location as well as over the Peyer's patches. Am J Physiol Gastrointest Liver Physiol 2013; 305:G341-7. [PMID: 23832518 PMCID: PMC3761247 DOI: 10.1152/ajpgi.00046.2013] [Citation(s) in RCA: 250] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Colon has been shown to have a two-layered mucus system where the inner layer is devoid of bacteria. However, a complete overview of the mouse gastrointestinal mucus system is lacking. We now characterize mucus release, thickness, growth over time, adhesive properties, and penetrability to fluorescent beads from stomach to distal colon. Colon displayed spontaneous mucus release and all regions released mucus in response to carbachol and PGE2, except the distal colon and domes of Peyer's patches. Stomach and colon had an inner mucus layer that was adherent to the epithelium. In contrast, the small intestine and Peyer's patches had a single mucus layer that was easily aspirated. The inner mucus layer of the distal colon was not penetrable to beads the size of bacteria and the inner layer of the proximal colon was only partly penetrable. In contrast, the inner mucus layer of stomach was fully penetrable, as was the small intestinal mucus. This suggests a functional organization of the intestinal mucus system, where the small intestine has loose and penetrable mucus that may allow easy penetration of nutrients, in contrast to the stomach, where the mucus provides physical protection, and the colon, where the mucus separates bacteria from the epithelium. This knowledge of the mucus system and its organization improves our understanding of the gastrointestinal tract physiology.
Collapse
Affiliation(s)
- Anna Ermund
- Dept. Medical Biochemistry, Univ. of Gothenburg, Box 440, 40530 Gothenburg, Sweden.
| | | | | | | | | |
Collapse
|
28
|
Takamura A, Ito M, Boda T, Matsumoto Y, Tanaka S, Yoshihara M, Chayama K. High expression of gastrin receptor protein in injured mucosa of Helicobacter pylori-positive gastritis. Dig Dis Sci 2013; 58:634-40. [PMID: 23053898 DOI: 10.1007/s10620-012-2427-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 09/19/2012] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND AIM Gastrin is a growth factor for the gastric epithelial cells. However, it is unknown how gastric receptor (GR) expression is regulated in the gastric mucosa. We studied GR expression using a newly raised antibody and investigated the relationship between GR expression and gastritis. METHODS Gastric receptor expression in 63 human gastric mucosa was studied. Helicobacter pylori infection and histological gastritis status were evaluated in gastric biopsy samples. In gastric ulcer cases, additional biopsy specimens were taken from injured mucosa. Fasting sera were collected and serum gastrin level evaluated. MKN-28 cells were cultured at various pH conditions, and the change in GR expression was determined. RESULTS Gastric receptor expression was detected in the foveolar epithelium of the gastric mucosa, and its expression was stronger in patients infected with H. pylori. In particular, higher expression was detected in regenerating injured mucosa. There was no association between gastritis score/serum gastrin level and GR expression in H. pylori-positive cases. In MKN-28 cells, GR protein expression was lower in neutral conditions than in acidic or alkaline conditions. CONCLUSION Gastric mucosal injury with H. pylori infection destroys the pH barrier on the foveolar epithelium and may induce GR expression through pH changes.
Collapse
Affiliation(s)
- Akemi Takamura
- Department of Gastroenterology and Metabolism, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
| | | | | | | | | | | | | |
Collapse
|
29
|
Swami SB, Thakor NJ, Haldankar PM, Kalse SB. Jackfruit and Its Many Functional Components as Related to Human Health: A Review. Compr Rev Food Sci Food Saf 2012. [DOI: 10.1111/j.1541-4337.2012.00210.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
30
|
McColl KEL, Aihara E, Kenny S, Varro A, Montrose MH. The elegance of the gastric mucosal barrier: designed by nature for nature. Gut 2012; 61:787-8. [PMID: 22147513 DOI: 10.1136/gutjnl-2011-301612] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Kenneth E L McColl
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, 44 Church Street, Glasgow G11 6NT, UK.
| | | | | | | | | |
Collapse
|
31
|
Rocha BS, Gago B, Barbosa RM, Lundberg JO, Radi R, Laranjinha J. Intragastric nitration by dietary nitrite: implications for modulation of protein and lipid signaling. Free Radic Biol Med 2012; 52:693-698. [PMID: 22154654 DOI: 10.1016/j.freeradbiomed.2011.11.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 11/01/2011] [Accepted: 11/10/2011] [Indexed: 12/19/2022]
Abstract
Inorganic nitrite, derived from the reduction of nitrate in saliva, has recently emerged as a protagonist in nitric oxide ((•)NO) biology as it can be univalently reduced to (•)NO, in the healthy human stomach. Important physiological implications have been attributed to nitrite-derived (•)NO in the gastrointestinal tract, namely modulation of host defense, blood flow, mucus formation and motility. At acidic pH, nitrite generates different nitrogen oxides depending on the local microenvironment (redox status, gastric content, pH, inflammatory conditions), including (•)NO, nitrogen dioxide ((•)NO(2)), dinitrogen trioxide (N(2)O(3)), and peroxynitrite. Thus, the gastric environment is a significant source of nitrating and nitrosating agents, especially in individuals consuming a nitrate/nitrite-rich diet on a daily basis. Both, the gastric lumen and mucosa contain putative targets for nitration, not only proteins and lipids from ingested aliments but also endogenous proteins secreted by the oxyntic glands. The physiological and functional consequences of nitration of gastric mediators will impact on local processes including food digestion and ulcerogenesis. Additionally, gastric nitration products (such as nitrated lipids) may be absorbed and affect systemic pathways. Thus, dietary ingestion of nitrate will have direct consequences for endogenous protein nitration, as indicated by our preliminary data.
Collapse
Affiliation(s)
- Bárbara S Rocha
- Faculty of Pharmacy and Center for Neurosciences and Cell Biology, University of Coimbra, Health Sciences Campus. Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Bruno Gago
- Faculty of Pharmacy and Center for Neurosciences and Cell Biology, University of Coimbra, Health Sciences Campus. Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal; Health Science Department, University of Aveiro
| | - Rui M Barbosa
- Faculty of Pharmacy and Center for Neurosciences and Cell Biology, University of Coimbra, Health Sciences Campus. Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Jon O Lundberg
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Rafael Radi
- Departamento de Bioquímica, Facultad de Medicina, Universidad de La República, Montevideo, Uruguay; Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de La República, Montevideo, Uruguay
| | - João Laranjinha
- Faculty of Pharmacy and Center for Neurosciences and Cell Biology, University of Coimbra, Health Sciences Campus. Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
| |
Collapse
|
32
|
Abstract
The nature of the mucus gel layer covering the gastrointestinal tract makes it difficult to study outside its natural site attached to the mucosa. Here, we describe a technique for intravital microscopy studies of the mucus gel layer from the stomach down to the colon in anesthetized rats and mice. Mucus thickness and accumulation rate in each segment of the gastrointestinal tract is measured with a micropipette technique under observation through a stereomicroscope. In this way, the nature of the mucus gel in vivo is readily studied, and effects of interventions or disease on the mucus can be determined in longitudinal studies or by comparing animals. Using this technique, we have been able to demonstrate that there are two forms of mucus gel adherent to the stomach and colon mucosa: one layer which is removable by suction and an underlying firm adherent gel layer, while in the small intestine, all mucus adhering to the mucosa can easily be removed.
Collapse
Affiliation(s)
- Lena Holm
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden.
| | | |
Collapse
|
33
|
Varum FJO, Veiga F, Sousa JS, Basit AW. Mucus thickness in the gastrointestinal tract of laboratory animals. ACTA ACUST UNITED AC 2011; 64:218-27. [PMID: 22221097 DOI: 10.1111/j.2042-7158.2011.01399.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVES The objective of this study was to systematically assess the mucus thickness in the gastrointestinal tract of laboratory animals commonly used in preclinical studies. METHODS Mucus thickness was studied post-mortem in the rat, rabbit and pig, using cryosections stained by the modified periodic acid Schiff/Alcian blue method. KEY FINDINGS The mucus thickness in the fundus region of the stomach was higher in the pig (190.7 ± 80.7 µm) than in the rabbit (155.1 ± 85.8 µm) and the rat (31.3 ± 11.4 µm). However, along the small intestine (ileum), mucus was thicker in the rabbit (147.8 ± 115.6 µm), followed by the pig (53.8 ± 22.1 µm) and the rat (34.1 ± 14.9 µm). This rank order was also observed in the ascending colon. CONCLUSIONS Inter-species variability in mucus thickness along the gut was demonstrated and suggests that the pig resembles more closely the mucus pattern of humans. This may be highly relevant when preclinical animal models are used in drug absorption studies or in the development of oral mucoadhesive drug delivery systems.
Collapse
Affiliation(s)
- Felipe J O Varum
- Center for Pharmaceutical Studies, Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal The School of Pharmacy, University of London, London, UK
| | | | | | | |
Collapse
|
34
|
Seidler U, Song P, Xiao F, Riederer B, Bachmann O, Chen M. Recent advances in the molecular and functional characterization of acid/base and electrolyte transporters in the basolateral membranes of gastric and duodenal epithelial cells. Acta Physiol (Oxf) 2011; 201:3-20. [PMID: 20331540 DOI: 10.1111/j.1748-1716.2010.02107.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
All segments of the gastrointestinal tract are comprised of an elaborately folded epithelium that expresses a variety of cell types and performs multiple secretory and absorptive functions. While the apical membrane expresses the electrolyte transporters that secrete or absorb electrolytes and water, basolateral transporters regulate the secretory or absorptive rates. During gastric acid formation, Cl⁻/HCO₃⁻ and Na(+) /H(+) exchange and other transporters secure Cl⁻ re-supply as well as pH and volume regulation. Gastric surface cells utilize ion transporters to secrete HCO₃⁻, maintain pH(i) during a luminal acid load and repair damaged surface areas during the process of epithelial restitution. Na(+)/H(+) exchange and Na(+)/HCO₃⁻ cotransport serve basolateral acid/base import for gastroduodenal HCO₃⁻ secretion. The gastric and duodenal epithelium also absorbs salt and water. Recent molecular information on novel ion transporters expressed in the gastric and duodenal epithelium has exploded; however, a function has not been found yet for all transporters. The purpose of this review is to summarize current knowledge on the molecular identity and cellular function of basolateral ion transporters in the gastric and duodenal epithelium.
Collapse
Affiliation(s)
- U Seidler
- Department of Gastroenterology, Hepatology, and Endocrinology, Hannover Medical School, Germany.
| | | | | | | | | | | |
Collapse
|
35
|
Varum FJ, Veiga F, Sousa JS, Basit AW. An investigation into the role of mucus thickness on mucoadhesion in the gastrointestinal tract of pig. Eur J Pharm Sci 2010; 40:335-41. [DOI: 10.1016/j.ejps.2010.04.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 04/13/2010] [Accepted: 04/14/2010] [Indexed: 12/16/2022]
|
36
|
Demitrack ES, Soleimani M, Montrose MH. Damage to the gastric epithelium activates cellular bicarbonate secretion via SLC26A9 Cl(-)/HCO(3)(-). Am J Physiol Gastrointest Liver Physiol 2010; 299:G255-64. [PMID: 20413716 PMCID: PMC2904109 DOI: 10.1152/ajpgi.00037.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gastric surface pH (pH(o)) transiently increases in response to focal epithelial damage. The sources of that increase, either from paracellular leakage of interstitial fluid or transcellular acid/base fluxes, have not been determined. Using in vivo microscopy approaches we measured pH(o) with Cl-NERF, tissue permeability with intravenous fluorescent-dextrans to label interstitial fluid (paracellular leakage), and gastric epithelial intracellular pH (pH(i)) with SNARF-5F (cellular acid/base fluxes). In response to two-photon photodamage, we found that cell-impermeant dyes entered damaged cells from luminal or tissue compartments, suggesting a possible slow transcellular, but not paracellular, route for increased permeability after damage. Regarding cytosolic acid/base status, we found that damaged cells acidified (6.63 +/- 0.03) after photodamage, compared with healthy surface cells both near (7.12 +/- 0.06) and far (7.07 +/- 0.04) from damage (P < 0.05). This damaged cell acidification was further attenuated with 20 muM intravenous EIPA (6.34 +/- 0.05, P < 0.05) but unchanged by addition of 0.5 mM luminal H(2)DIDS (6.64 +/- 0.08, P > 0.05). Raising luminal pH did not realkalinize damaged cells, suggesting that the mechanism of acidification is not attributable to leakiness to luminal protons. Inhibition of apical HCO(3)(-) secretion with 0.5 mM luminal H(2)DIDS or genetic deletion of the solute-like carrier 26A9 (SLC26A9) Cl(-)/HCO(3)(-) exchanger blocked the pH(o) increase normally observed in control animals but did not compromise repair of damaged tissue. Addition of exogenous PGE(2) significantly increased pH(o) in wild-type, but not SLC26A9 knockout, animals, suggesting that prostaglandin-stimulated HCO(3)(-) secretion is fully mediated by SLC26A9. We conclude that cellular HCO(3)(-) secretion, likely through SLC26A9, is the dominant mechanism whereby surface pH transiently increases in response to photodamage.
Collapse
Affiliation(s)
| | - Manoocher Soleimani
- 2Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | | |
Collapse
|
37
|
Petersson J, Carlström M, Schreiber O, Phillipson M, Christoffersson G, Jägare A, Roos S, Jansson EA, Persson AEG, Lundberg JO, Holm L. Gastroprotective and blood pressure lowering effects of dietary nitrate are abolished by an antiseptic mouthwash. Free Radic Biol Med 2009; 46:1068-75. [PMID: 19439233 DOI: 10.1016/j.freeradbiomed.2009.01.011] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 01/09/2009] [Accepted: 01/09/2009] [Indexed: 12/20/2022]
Abstract
Recently, it has been suggested that the supposedly inert nitrite anion is reduced in vivo to form bioactive nitric oxide with physiological and therapeutic implications in the gastrointestinal and cardiovascular systems. Intake of nitrate-rich food such as vegetables results in increased levels of circulating nitrite in a process suggested to involve nitrate-reducing bacteria in the oral cavity. Here we investigated the importance of the oral microflora and dietary nitrate in regulation of gastric mucosal defense and blood pressure. Rats were treated twice daily with a commercial antiseptic mouthwash while they were given nitrate-supplemented drinking water. The mouthwash greatly reduced the number of nitrate-reducing oral bacteria and as a consequence, nitrate-induced increases in gastric NO and circulating nitrite levels were markedly reduced. With the mouthwash the observed nitrate-induced increase in gastric mucus thickness was attenuated and the gastroprotective effect against an ulcerogenic compound was lost. Furthermore, the decrease in systemic blood pressure seen during nitrate supplementation was now absent. These results suggest that oral symbiotic bacteria modulate gastrointestinal and cardiovascular function via bioactivation of salivary nitrate. Excessive use of antiseptic mouthwashes may attenuate the bioactivity of dietary nitrate.
Collapse
Affiliation(s)
- Joel Petersson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Wallace JL. Prostaglandins, NSAIDs, and gastric mucosal protection: why doesn't the stomach digest itself? Physiol Rev 2008; 88:1547-65. [PMID: 18923189 DOI: 10.1152/physrev.00004.2008] [Citation(s) in RCA: 405] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Except in rare cases, the stomach can withstand exposure to highly concentrated hydrochloric acid, refluxed bile salts, alcohol, and foodstuffs with a wide range of temperatures and osmolarity. This is attributed to a number of physiological responses by the mucosal lining to potentially harmful luminal agents, and to an ability to rapidly repair damage when it does occur. Since the discovery in 1971 that prostaglandin synthesis could be blocked by aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), there has been great interest in the contribution of prostaglandins to gastric mucosal defense. Prostaglandins modulate virtually every aspect of mucosal defense, and the importance of this contribution is evident by the increased susceptibility of the stomach to injury following ingestion of an NSAID. With chronic ingestion of these drugs, the development of ulcers in the stomach is a significant clinical concern. Research over the past two decades has helped to identify some of the key events triggered by NSAIDs that contribute to ulcer formation and/or impair ulcer healing. Recent research has also highlighted the fact that the protective functions of prostaglandins in the stomach can be carried out by other mediators, in particular the gaseous mediators nitric oxide and hydrogen sulfide. Better understanding of the mechanisms through which the stomach is able to resist injury in the presence of luminal irritants is helping to drive the development of safer anti-inflammatory drugs, and therapies to accelerate and improve the quality of ulcer healing.
Collapse
Affiliation(s)
- John L Wallace
- Inflammation Research Network, University of Calgary, Calgary, Alberta, Canada.
| |
Collapse
|
39
|
Phillipson M, Johansson MEV, Henriksnäs J, Petersson J, Gendler SJ, Sandler S, Persson AEG, Hansson GC, Holm L. The gastric mucus layers: constituents and regulation of accumulation. Am J Physiol Gastrointest Liver Physiol 2008; 295:G806-12. [PMID: 18719000 DOI: 10.1152/ajpgi.90252.2008] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The mucus layer continuously covering the gastric mucosa consists of a loosely adherent layer that can be easily removed by suction, leaving a firmly adherent mucus layer attached to the epithelium. These two layers exhibit different gastroprotective roles; therefore, individual regulation of thickness and mucin composition were studied. Mucus thickness was measured in vivo with micropipettes in anesthetized mice [isoflurane; C57BL/6, Muc1-/-, inducible nitric oxide synthase (iNOS)-/-, and neuronal NOS (nNOS)-/-] and rats (inactin) after surgical exposure of the gastric mucosa. The two mucus layers covering the gastric mucosa were differently regulated. Luminal administration of PGE(2) increased the thickness of both layers, whereas luminal NO stimulated only firmly adherent mucus accumulation. A new gastroprotective role for iNOS was indicated since iNOS-deficient mice had thinner firmly adherent mucus layers and a lower mucus accumulation rate, whereas nNOS did not appear to be involved in mucus secretion. Downregulation of gastric mucus accumulation was observed in Muc1-/- mice. Both the firmly and loosely adherent mucus layers consisted of Muc5ac mucins. In conclusion, this study showed that, even though both the two mucus layers covering the gastric mucosa consist of Muc5ac, they are differently regulated by luminal PGE(2) and NO. A new gastroprotective role for iNOS was indicated since iNOS-/- mice had a thinner firmly adherent mucus layer. In addition, a regulatory role of Muc1 was demonstrated since downregulation of gastric mucus accumulation was observed in Muc1-/- mice.
Collapse
Affiliation(s)
- Mia Phillipson
- Dept. of Medical Cell Biology, Div. of Integrative Physiology, Biomedical Ctr., Uppsala Univ., P. O. Box 571, SE-751 23 Uppsala, Sweden.
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Scott DR, Marcus EA, Wen Y, Oh J, Sachs G. Gene expression in vivo shows that Helicobacter pylori colonizes an acidic niche on the gastric surface. Proc Natl Acad Sci U S A 2007; 104:7235-40. [PMID: 17438279 PMCID: PMC1855417 DOI: 10.1073/pnas.0702300104] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Helicobacter pylori is a gastric-dwelling pathogen responsible, with acid secretion, for peptic ulcer and a 20-fold increase in the risk of gastric cancer. Several transcriptomes have been described after short-term exposure to acidity in vitro, but there are no data identifying the effects of chronic gastric exposure on bacterial gene expression. Comparison of the in vivo to the in vitro transcriptome at pH 7.4 identified several groups of genes of known function that increased expression >2-fold, and three of these respond both to acidity in vitro and to gastric infection. Almost all known acid acclimation genes are highly up-regulated. These include ureA, ureB, and rocF and the pH-gated urea channel, ureI. There is also up-regulation of two groups of motility and chemotaxis genes and for pathogenicity island genes, especially cagA, a predictor for pathogenicity. Most of these genes interact with HP0166, the response element of the pH-sensing two-component histidine kinase, HP0165/HP0166, ArsRS. Based on the pH profile of survival of ureI deletion mutants in vitro and their inability to survive in gastric acidity, the habitat of the organism at the gastric surface is acidic with a pH < or = 4.0. Hence, the pH of the habitat of H. pylori on the surface of the stomach largely determines the regulation of these specific groups of genes.
Collapse
Affiliation(s)
- David R. Scott
- Departments of *Physiology and
- Veterans Administration Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073; and
- To whom correspondence may be addressed. E-mail: or
| | - Elizabeth A. Marcus
- Departments of *Physiology and
- Veterans Administration Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073; and
| | - Yi Wen
- Departments of *Physiology and
- Veterans Administration Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073; and
| | - Jane Oh
- Department of Internal Medicine, Ewha Womans University, Dongdaemun Hospital, 70 Chongro 6-ka, Chongro-ku, Seoul 110-783, Korea
| | - George Sachs
- Departments of *Physiology and
- Medicine, David Geffen School of Medicine, University of California, 405 Hilgard Avenue, Los Angeles, CA 90024
- Veterans Administration Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073; and
- To whom correspondence may be addressed. E-mail: or
| |
Collapse
|
41
|
Petersson J, Phillipson M, Jansson EA, Patzak A, Lundberg JO, Holm L. Dietary nitrate increases gastric mucosal blood flow and mucosal defense. Am J Physiol Gastrointest Liver Physiol 2007; 292:G718-24. [PMID: 17082222 DOI: 10.1152/ajpgi.00435.2006] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Salivary nitrate from dietary or endogenous sources is reduced to nitrite by oral bacteria. In the acidic stomach, nitrite is further reduced to bioactive nitrogen oxides, including nitric oxide (NO). In this study, we investigated the gastroprotective role of nitrate intake and of luminally applied nitrite against provocation with diclofenac and taurocholate. Mucosal permeability ((51)Cr-EDTA clearance) and gastric mucosal blood flow (laser-Doppler flowmetry) were measured in anesthetized rats, either pretreated with nitrate in the drinking water or given acidified nitrite luminally. Diclofenac was given intravenously and taurocholate luminally to challenge the gastric mucosa. Luminal NO content and nitrite content in the gastric mucus were determined by chemiluminescence. The effect of luminal administration of acidified nitrite on the mucosal blood flow was also investigated in endothelial nitric oxide synthase-deficient mice. Rats pretreated with nitrate or given nitrite luminally had higher gastric mucosal blood flow than controls. Permeability increased more during the provocation in the controls than in the nitrate- and nitrite-treated animals. Dietary nitrate increased luminal NO levels 50 times compared with controls. Nitrate intake also resulted in nitrite accumulation in the loosely adherent mucous layer; after removal of this mucous layer, blood flow was reduced. Nitrite administrated luminally in endothelial nitric oxide synthase-deficient mice increased mucosal blood flow. We conclude that dietary nitrate and direct luminal application of acidified nitrite decrease diclofenac- and taurocholate-induced mucosal damage. The gastroprotective effect likely involves a higher mucosal blood flow caused by nonenzymatic NO production. These data suggest an important physiological role of nitrate in the diet.
Collapse
Affiliation(s)
- Joel Petersson
- Medical Cell Biology, Uppsala University, Uppsala, Sweden.
| | | | | | | | | | | |
Collapse
|
42
|
Henriksnäs J, Phillipson M, Storm M, Engstrand L, Soleimani M, Holm L. Impaired mucus-bicarbonate barrier in Helicobacter pylori-infected mice. Am J Physiol Gastrointest Liver Physiol 2006; 291:G396-403. [PMID: 16614375 DOI: 10.1152/ajpgi.00017.2006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To resist the harsh intrinsic milieu, several lines of defense exist in the stomach. The aim of this study was to investigate the effect of the gastric pathogen Helicobacter pylori on these mechanisms in vivo. We used FVB/N mice expressing human alpha-1,3/4-fucosyl transferase (producing Lewis b epitopes) and inoculated with H. pylori 1. Mice were anesthetized with isoflurane or Hypnorm-midazolam, the stomach was exteriorized, and the surface of the corpus mucosa was exposed. Mucus thickness was measured with micropipettes, juxtamucosal pH (pH(jm)) was measured with pH-sensitive microelectrodes, blood flow was measured with laser-Doppler flowmetry, and mRNA levels of the bicarbonate transporter SLC26A9 were quantified with real-time PCR. The increase in mucosal blood flow seen in response to luminal acid (pH 1.5) in control animals (140 +/- 9% of control) was abolished in infected mice. The firmly adherent mucus layer was significantly thinner in infected mice (31 +/- 2 microm) than in control mice (46 +/- 5 microm), and no mucus accumulation occurred in infected mice. pH(jm) decreased significantly more on exposure to luminal acid in infected mice (luminal pH 1.5, pH(jm) 2.4 +/- 0.7) than in control mice (pH(jm) 6.4 +/- 0.5). Despite reduced pH(jm), SLC26A9 mRNA expression was significantly, by increased 1.9-fold, in infected mice. The reduction in pH(jm) by infection with H. pylori might be due to a reduced firmly adherent mucus layer, increased mucus permeability to H(+), and/or inhibition of bicarbonate transport. The upregulation of SLC26A9 in H. pylori-infected epithelium might be a result of continuous inhibition of the transporter, e.g., by ammonium, a H. pylori product, which has been previously shown to inhibit SLC26A9.
Collapse
Affiliation(s)
- Johanna Henriksnäs
- Dept. of Medical Cell Biology, Uppsala Univ., PO Box 571, Uppsala SE-751 23, Sweden.
| | | | | | | | | | | |
Collapse
|
43
|
N/A, 任 建. N/A. Shijie Huaren Xiaohua Zazhi 2005; 13:2578-2581. [DOI: 10.11569/wcjd.v13.i21.2578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
|
44
|
Henriksnäs J, Phillipson M, Petersson J, Engstrand L, Holm L. An in vivo model for gastric physiological and pathophysiological studies in the mouse. ACTA ACUST UNITED AC 2005; 184:151-9. [PMID: 15916675 DOI: 10.1111/j.1365-201x.2005.01434.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM In vivo models for studying gastrointestinal physiology and pathophysiology are well established in rats. Since a number of genetically modified mice are available there is a need for reliable mouse models. The aim of this project was to develop an in vivo mouse model for gastrointestinal studies. METHODS C57bl/6, NMRI and transgenic FVB/N (expressing human alpha-1,3/4-fucosyltransferase) mice were anaesthetized with isoflurane and the gastric mucosa exteriorized for intravital microscopy. Acid-base status and acid secretion were measured and blood pressure was continuously monitored. Gastric mucosal blood flow was recorded by laser-Doppler flowmetry. Mucus thickness and accumulation rate were measured with micropipettes. RESULTS We have developed an in vivo mouse model for studies of the gastric mucosa. With isoflurane anaesthesia the preparation can be studied for up to 5 h with stable blood pressure and mucosal blood flow. Acid-base status agrees with results from other laboratories. Blood flow increased in both C57bl/6 and alpha1.3/4-FT mice in response to luminal HCl, and the mucus gel could be divided into a firmly and a loosely adherent layer, all comparable with results in the rat. However, the firmly adherent mucus layer was thinner (45 +/- 2 microm), and the mucus accumulation rate lower, than in the rat. Furthermore, both basal and stimulated acid secretion showed lower outputs than in the rat. CONCLUSIONS This model has great potential for investigations of gastrointestinal physiology and pathophysiology and can be applied for Helicobacter pylori infection studies.
Collapse
Affiliation(s)
- J Henriksnäs
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden.
| | | | | | | | | |
Collapse
|
45
|
Xu J, Henriksnäs J, Barone S, Witte D, Shull GE, Forte JG, Holm L, Soleimani M. SLC26A9 is expressed in gastric surface epithelial cells, mediates Cl-/HCO3- exchange, and is inhibited by NH4+. Am J Physiol Cell Physiol 2005; 289:C493-505. [PMID: 15800055 DOI: 10.1152/ajpcell.00030.2005] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
HCO3- secretion by gastric mucous cells is essential for protection against acidic injury and peptic ulcer. Herein we report the identification of an apical HCO3- transporter in gastric surface epithelial cells. Northern hybridization and RT-PCR demonstrate the expression of this transporter, also known as SLC26A9, in mouse and rat stomach and trachea (but not kidney). In situ hybridization in mouse stomach showed abundant expression of SLC26A9 in surface epithelial cells with apical localization on immunofluorescence labeling. Functional studies in HEK-293 cells demonstrated that SLC26A9 mediates Cl-/HCO3- exchange and is also capable of Cl--independent HCO3- extrusion. Unlike other anion exchangers or transport proteins reported to date, SLC26A9 activity is inhibited by ammonium (NH4+). The inhibitory effect of NH4+ on gastric HCO3- secretion was also indicated by reduced gastric juxtamucosal pH (pHjm) in rat stomach in vivo. This report is the first to describe the inhibition of HCO3- transport in vitro and the reduction of pHjm in stomach in vivo by NH4+. Given its critical localization on the apical membrane of surface epithelial cells, its ability to transport HCO3-, and its inhibition by NH4+, we propose that SLC26A9 mediates HCO3- secretion in surface epithelial cells and is essential for protection against acidic injury in the stomach. Disease states that are associated with increased ammonia (NH3)/NH4+ generation (e.g., Helicobacter pylori) may impair gastric HCO3- secretion and therefore predispose patients to peptic ulcer by inhibiting SLC26A9.
Collapse
Affiliation(s)
- Jie Xu
- Department of Medicine, University of Cincinnati, Cincinnati, OH 45267-0585, USA
| | | | | | | | | | | | | | | |
Collapse
|
46
|
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.
Collapse
Affiliation(s)
- Adrian Allen
- Physiological Sciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom
| | | |
Collapse
|
47
|
Björne H H, Petersson J, Phillipson M, Weitzberg E, Holm L, Lundberg JO. Nitrite in saliva increases gastric mucosal blood flow and mucus thickness. J Clin Invest 2004; 113:106-14. [PMID: 14702114 PMCID: PMC300767 DOI: 10.1172/jci19019] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2003] [Accepted: 10/21/2003] [Indexed: 12/18/2022] Open
Abstract
Salivary nitrate from dietary or endogenous sources is reduced to nitrite by oral bacteria. In the acidic stomach, nitrite is further reduced to NO and related compounds, which have potential biological activity. We used an in vivo rat model as a bioassay to test effects of human saliva on gastric mucosal blood flow and mucus thickness. Gastric mucosal blood flow and mucus thickness were measured after topical administration of human saliva in HCl. The saliva was collected either after fasting (low in nitrite) or after ingestion of sodium nitrate (high in nitrite). In additional experiments, saliva was exchanged for sodium nitrite at different doses. Mucosal blood flow was increased after luminal application of nitrite-rich saliva, whereas fasting saliva had no effects. Also, mucus thickness increased in response to nitrite-rich saliva. The effects of nitrite-rich saliva were similar to those of topically applied sodium nitrite. Nitrite-mediated effects were associated with generation of NO and S-nitrosothiols. In addition, pretreatment with an inhibitor of guanylyl cyclase markedly inhibited nitrite-mediated effects on blood flow. We conclude that nitrite-containing human saliva given luminally increases gastric mucosal blood flow and mucus thickness in the rat. These effects are likely mediated through nonenzymatic generation of NO via activation of guanylyl cyclase. This supports a gastroprotective role of salivary nitrate/nitrite.
Collapse
Affiliation(s)
- HåKan Björne H
- Department of Anesthesiology and Intensive Care, Karolinska Hospital, Stockholm, Sweden
| | | | | | | | | | | |
Collapse
|
48
|
Björne H H, Petersson J, Phillipson M, Weitzberg E, Holm L, Lundberg JO. Nitrite in saliva increases gastric mucosal blood flow and mucus thickness. J Clin Invest 2004. [PMID: 14702114 DOI: 10.1172/jci200419019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Salivary nitrate from dietary or endogenous sources is reduced to nitrite by oral bacteria. In the acidic stomach, nitrite is further reduced to NO and related compounds, which have potential biological activity. We used an in vivo rat model as a bioassay to test effects of human saliva on gastric mucosal blood flow and mucus thickness. Gastric mucosal blood flow and mucus thickness were measured after topical administration of human saliva in HCl. The saliva was collected either after fasting (low in nitrite) or after ingestion of sodium nitrate (high in nitrite). In additional experiments, saliva was exchanged for sodium nitrite at different doses. Mucosal blood flow was increased after luminal application of nitrite-rich saliva, whereas fasting saliva had no effects. Also, mucus thickness increased in response to nitrite-rich saliva. The effects of nitrite-rich saliva were similar to those of topically applied sodium nitrite. Nitrite-mediated effects were associated with generation of NO and S-nitrosothiols. In addition, pretreatment with an inhibitor of guanylyl cyclase markedly inhibited nitrite-mediated effects on blood flow. We conclude that nitrite-containing human saliva given luminally increases gastric mucosal blood flow and mucus thickness in the rat. These effects are likely mediated through nonenzymatic generation of NO via activation of guanylyl cyclase. This supports a gastroprotective role of salivary nitrate/nitrite.
Collapse
Affiliation(s)
- HåKan Björne H
- Department of Anesthesiology and Intensive Care, Karolinska Hospital, Stockholm, Sweden
| | | | | | | | | | | |
Collapse
|
49
|
Abstract
The gastric mucosa is frequently exposed to endogenously secreted hydrochloric acid of high acidity. Gastric mucosal defense mechanisms are arranged at different levels of the gastric mucosa and must work in unison to maintain its integrity. In this work, several mechanisms underlying gastric mucosal resistance to strong acid were investigated in anesthetized rats and mice. The main findings were as follows: Only when acid secretion occurred did the pH gradient in the mucus gel withstand back-diffusion of luminal acid (100 mM or 155 mM HCl), and keep the juxtamucosal pH (pH(jm)) neutral. Thus, with no on-going acid secretion and low luminal pH, the pH gradient was destroyed. Bicarbonate ions, produced concomitant with hydrogen ions in the parietal cells during acid secretion and transported by the blood to the surface epithelium, were carried transepithelially through a DIDS-sensitive transport. Prostaglandin-dependent bicarbonate secretion seemed to be less important in maintaining a neutral pH(jm). Removal of the loosely adherent mucus layer did not influence the maintenance of the pH(jm). Hence, only the firmly adherent mucus gel layer, approximately 80 microm thick, seemed to be important for the pH(jm). Staining of the mucus gel with a pH-sensitive dye revealed that secreted acid penetrated the mucus gel from the crypt openings toward the gastric lumen only in restricted paths (channels). One crypt opening was attached to one channel, and the channel was irreversibly formed during acid secretion. Gastric mucosal blood flow increased on application of strong luminal acid (155 mM HCl). This acid-induced hyperemia involved the inducible but not the neural isoform of nitric oxide synthase. These results suggest a novel role for iNOS in gastric mucosal protection and indicate that iNOS is constitutively expressed in the gastric mucosa.
Collapse
Affiliation(s)
- Mia Phillipson
- Department of Medical Cell Biology, Division of Physiology, Uppsala University, Uppsala, Sweden.
| |
Collapse
|
50
|
Xu J, Barone S, Petrovic S, Wang Z, Seidler U, Riederer B, Ramaswamy K, Dudeja PK, Shull GE, Soleimani M. Identification of an apical Cl-/HCO3- exchanger in gastric surface mucous and duodenal villus cells. Am J Physiol Gastrointest Liver Physiol 2003; 285:G1225-34. [PMID: 12893630 DOI: 10.1152/ajpgi.00236.2003] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The molecular identity of the apical HCO3(-)-secreting transporter in gastric mucous cells remains unknown despite its essential role in preventing injury and ulcer by gastric acid. Here we report the identification of a Cl-/HCO3- exchanger that is located on apical membranes of gastric surface epithelial cells. RT-PCR studies of mouse gastrointestinal tract mRNAs demonstrated that this transporter, known as anion exchanger isoform 4 (AE4), is expressed in both stomach and duodenum. Northern blot analysis of RNA from purified stomach epithelial cells indicated that AE4 is expressed at higher levels in mucous cells than in parietal cells. Immunoblotting experiments identified AE4 as a approximately 110- to 120-kDa protein in membranes from stomach epithelium and apical membranes from duodenum. Immunocytochemical staining demonstrated that AE4 is expressed in apical membranes of surface cells in both mouse and rabbit stomach and duodenum. Functional studies in oocytes indicated that AE4 functions as a Cl-/HCO3- exchanger. These data show that AE4 is an apical Cl-/HCO3- exchanger in gastric mucous cells and duodenal villus cells. On the basis of its function and location, we propose that AE4 may play an important role in mucosal protection.
Collapse
Affiliation(s)
- Jie Xu
- Department of Medicine, University of Cincinnati, Cincinnati, Ohio 45267, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|