|
1
|
Pauer SM, Buß B, Diener M, Ballout J. Time-dependent effects of tumor necrosis factor α on Ca 2+-dependent secretion in murine small intestinal organoids. Front Physiol 2024; 15:1382238. [PMID: 38737827 PMCID: PMC11082751 DOI: 10.3389/fphys.2024.1382238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 04/15/2024] [Indexed: 05/14/2024] Open
Abstract
Background Intestinal organoids are stem cell-derived, 3D "mini-guts" with similar functions as the native intestinal epithelium such as electrolyte transport or establishment of an epithelial barrier. During intestinal inflammation, epithelial functions are dysregulated by proinflammatory cytokines like tumor necrosis factor α (TNFα) and other messengers from the immune system resulting in a loss of electrolytes and water due to an impaired epithelial barrier and higher net secretion. Methods A murine small intestinal organoid model was established to study (long-term) effects of TNFα on the intestinal epithelium in vitro using live imaging, immunohistochemical staining and qPCR. Results TNFα induced apoptosis in intestinal organoids as indicated by an increased number of cells with immunoreactivity for cleaved caspase 3. Furthermore, TNFα exposure led to swelling of the organoids which was inhibited by bumetanide and was concomitant with an upregulation of the bumetanide-sensitive Na+-K+-2Cl- symporter 1 (NKCC1) as shown by qPCR. Fura-2 imaging experiments revealed time-dependent changes in Ca2+ signaling consisting of a rise in the basal cytosolic Ca2+ concentration at day 1 and an increase of the carbachol-induced Ca2+ response after 3 days TNFα exposure. This was prevented by preincubation with La3+, an inhibitor of non-selective cation channels, or by using a Ca2+-free buffer indicating an enhancement of the Ca2+ influx from the extracellular side by the cytokine. No significant changes in cDNA levels of epithelial barrier proteins could be observed in the presence of TNFα. Conclusion Intestinal organoids are a useful tool to study the mechanism underlying the TNFα-induced secretion on enterocytes such as the regulation of NKCC1 expression or the modulation of cellular Ca2+ signaling.
Collapse
Affiliation(s)
| | | | | | - Jasmin Ballout
- Institute for Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Giessen, Germany
| |
Collapse
|
|
2
|
Wang Y, Ji X, Zhao M, Li J, Yin H, Jin J, Zhao L. Modulation of tryptophan metabolism via AHR-IL22 pathway mediates the alleviation of DSS-induced colitis by chitooligosaccharides with different degrees of polymerization. Carbohydr Polym 2023; 319:121180. [PMID: 37567716 DOI: 10.1016/j.carbpol.2023.121180] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 06/27/2023] [Accepted: 07/06/2023] [Indexed: 08/13/2023]
Abstract
Oral administration of chitooligosaccharides (COS) has been reported to alleviate colitis in mice. However, the mechanism of action of COS with specific polymerization degree on gut inflammation and metabolism remains unclear. This study aimed to investigate the effects of chitobiose (COS2), chitotetraose (COS4), and chitohexaose (COS6) on colitis, and to elucidate their underlying mechanisms. COS2, COS4, and COS6 were able to significantly alleviate colonic injury and inflammation levels. COS6 has the best anti-inflammatory effect. Furthermore, COS6 could down-regulate the level of indoleamine-2,3-dioxygenase1 (IDO1) and restore the levels of indole, indoleacetic-3-acid (IAA), and indole-3-carbaldehyde (I3A) in the cecum of chronic colitis mice (p < 0.05), thereby regulating tryptophan metabolism. In the aromatic hydrocarbon receptor-IL-22 (AHR-IL-22) pathway, although there were differences between chronic colitis and acute colitis mice, COS intervention could restore the AHR-IL-22 pathway to normal, promote the expression of MUC2, and repair the intestinal mucosal barrier. In conclusion, the results of this study suggested that COS had a good inhibitory effect on IDO1 under inflammation and the changes of AHR and IL-22 levels at different stages of disease development. This provides new insights into the potential use of COS as a functional food for improving intestinal inflammation and metabolism.
Collapse
Affiliation(s)
- Yu Wang
- State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China
| | - Xiaoguo Ji
- State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology (SCICBT), Shanghai 200237, China; Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Shanghai 200237, China
| | - Mengyao Zhao
- State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China; Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Shanghai 200237, China
| | - Juan Li
- Organ Transplant Center, Shanghai Changzheng Hospital, Shanghai 200003, China
| | - Hao Yin
- Organ Transplant Center, Shanghai Changzheng Hospital, Shanghai 200003, China
| | - Jiayang Jin
- State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China; Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Shanghai 200237, China.
| | - Liming Zhao
- State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China; Organ Transplant Center, Shanghai Changzheng Hospital, Shanghai 200003, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology (SCICBT), Shanghai 200237, China.
| |
Collapse
|
|
3
|
Rivero-Gutiérrez B, Arredondo-Amador M, Gámez-Belmonte R, Sánchez de Medina F, Martínez-Augustin O. Leptin-resistant Zucker rats with trinitrobenzene sulfonic acid colitis present a reduced inflammatory response but enhanced epithelial damage. Am J Physiol Gastrointest Liver Physiol 2021; 321:G157-G170. [PMID: 34132111 DOI: 10.1152/ajpgi.00367.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The role of leptin in the development of intestinal inflammation remains controversial, since proinflammatory and anti-inflammatory effects have been described. This study describes the effect of the absence of leptin signaling in intestinal inflammation. Experimental colitis was induced by intrarectal administration of trinitrobenzene sulfonic acid (TNBS) to lean and obese Zucker rats (n = 10). Effects on inflammation and mucosal barrier were studied. Bacterial translocation and LPS concentration were evaluated together with colonic permeability to 4-kDa FITC-dextran. Obese Zucker rats showed a lower intestinal myeloperoxidase and alkaline phosphatase activity, reduced alkaline phosphatase sensitivity to levamisole, and diminished colonic expression of Nos2, Tnf, and Il6, indicating attenuated intestinal inflammation, associated with attenuated STAT3, AKT, and ERK signaling in the colonic tissue. S100a8 and Cxcl1 mRNA levels were maintained, suggesting that in the absence of leptin signaling neutrophil activation rather than infiltration is hampered. Despite the lower inflammatory response, leptin resistance enhanced intestinal permeability, reflecting an increased epithelial damage. This was shown by augmented LPS presence in the portal vein of colitic obese Zucker rats, associated with induction of tissue nonspecific alkaline phosphatase, LPS-binding protein, and CD14 hepatic expression (involved in LPS handling). This was linked to decreased ZO-1 immunoreactivity in tight junctions and lower occludin expression. Our results indicate that obese Zucker rats present an attenuated inflammatory response to TNBS, but increased intestinal epithelial damage allowing the passage of bacterial antigens.NEW & NOTEWORTHY Obese Zucker rats, which are resistant to leptin, exhibit a diminished inflammatory response in the trinitrobenzenesulfonic acid (TNBS) model of colitis, suggesting leptin role is proinflammatory. At the same time, obese Zucker rats present a debilitated intestinal barrier function, with increased translocation of LPS. Zucker rats present a dual response in the TNBS model of rat colitis.
Collapse
Affiliation(s)
- Belén Rivero-Gutiérrez
- Department of Pharmacology, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), School of Pharmacy, Instituto de Investigación Biosanitaria ibs.GRANADA, University of Granada, Granada, Spain
| | - María Arredondo-Amador
- Department of Pharmacology, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), School of Pharmacy, Instituto de Investigación Biosanitaria ibs.GRANADA, University of Granada, Granada, Spain
| | - Reyes Gámez-Belmonte
- Department of Pharmacology, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), School of Pharmacy, Instituto de Investigación Biosanitaria ibs.GRANADA, University of Granada, Granada, Spain
| | - Fermín Sánchez de Medina
- Department of Pharmacology, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), School of Pharmacy, Instituto de Investigación Biosanitaria ibs.GRANADA, University of Granada, Granada, Spain
| | - Olga Martínez-Augustin
- Department of Biochemistry and Molecular Biology II, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), School of Pharmacy, Instituto de Investigación Biosanitaria ibs.GRANADA, University of Granada, Granada, Spain
| |
Collapse
|
|
4
|
Ballout J, Diener M. Interactions between rat submucosal neurons and mast cells are modified by cytokines and neurotransmitters. Eur J Pharmacol 2019; 864:172713. [PMID: 31586631 DOI: 10.1016/j.ejphar.2019.172713] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 09/20/2019] [Accepted: 10/01/2019] [Indexed: 02/07/2023]
Abstract
The role of mast cells during inflammatory bowel diseases (IBD) is discussed controversially. Whereas several studies report an increase in mast cell density during IBD, others found a decrease. Recently, we observed a reduced response to mast cell degranulation induced by antigen contact in a colitis model. As the effects of mast cell mediators on epithelial ion transport are mediated indirectly via stimulation of secretomotor neurons, we investigated in vitro whether proinflammatory cytokines change the response to mast cell degranulation. Tumor necrosis factor α (TNFα) and a mix of proinflammatory cytokines caused an increase of short-circuit current (Isc) and tissue conductance in rat colon. Anion secretion induced by histamine was downregulated in the presence of interleukin-1β (IL-1β) and the cytokine mix, whereas the response to the mast cell stimulator compound 48/80 was not changed significantly. In a coculture of rat submucosal ganglionic cells with a mast cell line (RBL-2H3), TNFα preincubation for 1 d increased the percentage of neurons responding to mast cell degranulation with an increase of the cytosolic Ca2+ concentration and enhanced the amplitude of this response. Consequently, the downregulation of epithelial secretion is compensated by an increased sensitivity of secretomotor neurons leading to a constant response of the epithelium to compound 48/80. Furthermore, enteric neurons can modify mast cell functions as nicotine inhibited the increase in cytosolic Ca2+ concentration of RBL-2H3 cells and the Isc evoked by compound 48/80. Consequently, these in vitro models deliver new insights into cellular interactions in the gut wall under inflammatory conditions.
Collapse
Affiliation(s)
- Jasmin Ballout
- Institute for Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Germany
| | - Martin Diener
- Institute for Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Germany.
| |
Collapse
|
|
5
|
Romero-Calvo I, Ocón B, Gámez-Belmonte R, Hernández-Chirlaque C, de Jonge HR, Bijvelds MJ, Martínez-Augustin O, Sánchez de Medina F. Adenylyl cyclase 6 is involved in the hyposecretory status of experimental colitis. Pflugers Arch 2018; 470:1705-1717. [PMID: 30094477 DOI: 10.1007/s00424-018-2187-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 07/12/2018] [Accepted: 07/24/2018] [Indexed: 12/12/2022]
Abstract
One of the cardinal symptoms of intestinal inflammation is diarrhea. Acute intestinal inflammation is associated with inhibition of ion absorption and increased secretion, along with fluid leakage due to epithelial injury and changes in permeability. However, in the chronic situation, a downregulation of both absorptive and secretory transport has been reported. We investigated how experimental colitis reduces cAMP levels in intestinal epithelial cells through modulation of adenylyl cyclases (AC). Primary colonic epithelial cells obtained from rats with trinitrobenzenesulfonic acid colitis and non-colitic controls were analyzed for AC expression by RT-qPCR and Western blot, following a preliminary microarray analysis. AC6 and AC5 were found to be expressed in colonocytes, and downregulated by inflammation, with the former exhibiting considerably higher mRNA levels in both cases. To test the hypothesis that inflammatory cytokines may account for this effect, Caco 2 cells were treated with IL-1β, TNF-α, or IFN-γ. All three cytokines inhibited forskolin evoked short-circuit currents in Ussing chambers and lowered intracellular cAMP, but failed to alter AC6 mRNA levels. AC5/AC6 expression was however inhibited in mouse jejunal organoids treated with IFN-γ and TNF-α, but not IL-1β. Gene knockdown of AC6 resulted in a significant decrease of ion secretion in T84 cells. We conclude that the disturbances in ion secretion observed in rat TNBS colitis are associated with low intracellular levels of cAMP in the epithelium, which may be explained in part by the downregulation of AC5/AC6 expression by proinflammatory cytokines.
Collapse
Affiliation(s)
- Isabel Romero-Calvo
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, Campus de Cartuja s/n, 18071, Granada, Spain
| | - Borja Ocón
- Department of Pharmacology, CIBERehd, School of Pharmacy, Instituto de Investigación Biosanitaria ibs.GRANADA, University of Granada, Granada, Spain
| | - Reyes Gámez-Belmonte
- Department of Pharmacology, CIBERehd, School of Pharmacy, Instituto de Investigación Biosanitaria ibs.GRANADA, University of Granada, Granada, Spain
| | - Cristina Hernández-Chirlaque
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, Campus de Cartuja s/n, 18071, Granada, Spain
| | - Hugo R de Jonge
- Department of Gastroenterology and Hepatology, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Marcel J Bijvelds
- Department of Gastroenterology and Hepatology, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Olga Martínez-Augustin
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, Campus de Cartuja s/n, 18071, Granada, Spain.
| | - Fermín Sánchez de Medina
- Department of Pharmacology, CIBERehd, School of Pharmacy, Instituto de Investigación Biosanitaria ibs.GRANADA, University of Granada, Granada, Spain
| |
Collapse
|
|
6
|
Abstract
The gastrointestinal tract is innervated by several distinct populations of neurons, whose cell bodies either reside within (intrinsic) or outside (extrinsic) the gastrointestinal wall. Normally, most individuals are unaware of the continuous, complicated functions of these neurons. However, for patients with gastrointestinal disorders, such as IBD and IBS, altered gastrointestinal motility, discomfort and pain are common, debilitating symptoms. Although bouts of intestinal inflammation underlie the symptoms associated with IBD, increasing preclinical and clinical evidence indicates that infection and inflammation are also key risk factors for the development of other gastrointestinal disorders. Notably, a strong correlation exists between prior exposure to gut infection and symptom occurrence in IBS. This Review discusses the evidence for neuroplasticity (structural, synaptic or intrinsic changes that alter neuronal function) affecting gastrointestinal function. Such changes are evident during inflammation and, in many cases, long after healing of the damaged tissues, when the nervous system fails to reset back to normal. Neuroplasticity within distinct populations of neurons has a fundamental role in the aberrant motility, secretion and sensation associated with common clinical gastrointestinal disorders. To find appropriate therapeutic treatments for these disorders, the extent and time course of neuroplasticity must be fully appreciated.
Collapse
|
|
7
|
Acute exercises induce disorders of the gastrointestinal integrity in a murine model. Eur J Appl Physiol 2013; 114:609-17. [PMID: 24352573 DOI: 10.1007/s00421-013-2791-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 12/05/2013] [Indexed: 01/16/2023]
Abstract
PURPOSE Many endurance athletes complain about gastrointestinal (GI) symptoms. It is assumed that exercise-induced shift of perfusion with consecutive hypoperfusion of the enteral vascular system leads to an increased GI permeability and tissue damage. Therefore, the aim of the study was to investigate permeability, apoptosis, electrogenic ion transport (Isc), and tissue conductance (Gt) of the small intestine in a murine exercise model. METHODS After spirometry, male Swiss CD-1 mice were subjected to an intensive treadmill exercise (80% VO2max). Sedentary mice served as controls. The small intestine was removed at several time intervals post-exercise. Apoptotic cells were determined by the TUNEL method, while fluorescein isothiocyanate dextran permeation indicated intestinal permeability. The Gt and Isc measurements were carried out in a modified Ussing chamber. RESULTS Apoptosis of epithelial cells increased continuously until 24 h post exercise (0.8 ± 0.42 versus 39.2 ± 26.0%; p < 0.05). Compared with the control group the permeability increased 2 h after exercise (0.47 ± 0.07 versus 0.67 ± 0.14 FU/min; p < 0.05). Isc measurements of the ileum were augmented after 24 h (3.33 ± 0.56 versus 5.77 ± 1.16 μEq/h/cm(2); p < 0.05). At this time the Gt increased as well (28.8 ± 3.37 versus 32.5 ± 2.59 mS/cm(2); p < 0.05). CONCLUSION In the murine exercise model there is evidence that after intense endurance exercise repair processes occur in small intestinal epithelial cells, which affect permeability, Gt, and Isc. The formation of lamellipodia to close the "leaky" tight junctions caused by apoptosis might be an underlying mechanism.
Collapse
|
|
8
|
Steidle J, Würner L, Diener M. Altered response to hydrogen sulphide during experimental colitis in rats. J Anim Physiol Anim Nutr (Berl) 2012; 97:942-50. [PMID: 22963333 DOI: 10.1111/jpn.12000] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Hydrogen sulphide (H2 S) is produced in the intestine by sulphate-reducing bacteria and during metabolism of L-cysteine within the mucosa. This gasotransmitter induces anion secretion by stimulating enteric neurons and by a direct effect on epithelial cells. As H2 S is discussed to exert both pro- and anti-inflammatory actions, we aimed to investigate the role of H2 S during experimental colitis by comparing the effects of blockade of H2 S-forming endogenous enzymes with the effect of a S-reduced diet to diminish microbial production of H2 S. Rectal application of trinitrobenzenesulfonic acid (TNBS) was used to induce chronic colitis. The level of inflammation was assessed macroscopically and histologically. In Ussing chamber experiments, colonic specimens from TNBS-treated animals exhibited a higher tissue conductance, that is, a higher epithelial permeability, and a slightly reduced basal short-circuit current (a measure of net ion transport) in relation to non-inflamed control tissue. Analgetic treatment with flupirtine, a central antinociceptive analgetic, did not interfere with the induction of the inflammatory response so that all animals were treated with flupirtine to reduce pain and distress during the development of colitis. The secretory response evoked by an exogenous H2 S donor, NaHS, was significantly decreased after induction of colitis, whereas the response to Ca(2+) - or cAMP-dependent secretagogues was unaltered. This downregulation was not observed in the colitis group fed on a S-reduced diet. The decreased NaHS response indicates a desensitization of the tissue by inflammation, which might be explained by an upregulation of colonic H2 S production as described in some models of inflammation.
Collapse
Affiliation(s)
- J Steidle
- Institute for Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Giessen, Germany
| | - L Würner
- Institute for Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Giessen, Germany
| | - M Diener
- Institute for Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Giessen, Germany
| |
Collapse
|
|
9
|
Abstract
Diarrhoea is a hallmark of intestinal inflammation. The mechanisms operating in acute inflammation of the intestine are well characterized and are related to regulatory changes induced by inflammatory mediators such as prostaglandins, cytokines or reactive oxygen species, along with leakage due to epithelial injury and changes in permeability. In chronic colitis, however, the mechanisms are less well known, but it is generally accepted that both secretory and absorptive processes are inhibited. These disturbances in ionic transport may be viewed as an adaptation to protracted inflammation of the intestine, since prolonged intense secretion may be physiologically unacceptable in the long term. Mechanistically, the changes in transport may be due to adjustments in the regulation of the different processes involved, to broader epithelial alterations or frank damage, or to modulation of the transportome in terms of expression. In the present review, we offer a summary of the existing evidence on the status of the transportome in chronic intestinal inflammation.
Collapse
|
|
10
|
Bachmann O, Seidler U. News from the end of the gut--how the highly segmental pattern of colonic HCO₃⁻ transport relates to absorptive function and mucosal integrity. Biol Pharm Bull 2011; 34:794-802. [PMID: 21628874 DOI: 10.1248/bpb.34.794] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A number of transport mechanisms in the colonic epithelium contribute to HCO₃⁻ movement across the apical and basolateral membranes, but this ion has been largely regarded as a by-product of the transport functions it is involved in, such as NaCl or short chain fatty acid (SCFA) absorption. However, emerging data points to several specific roles of HCO₃⁻ for colonic epithelial physiology, including pH control in the colonic surface microenvironment, which is important for transport and immune functions, as well as the secretion and the rheological properties of the mucus gel. Furthermore, recent studies have demonstrated that colonic HCO₃⁻ transporters are expressed in a highly segmental as well as species-specific manner. This review summarizes recently gathered information on the functional anatomy of the colon, the roles of HCO₃⁻ in the colonic epithelium, colonic mucosal integrity, and the expression and function of HCO₃⁻ transporting mechanisms in health and disease.
Collapse
Affiliation(s)
- Oliver Bachmann
- Department of Gastroenterology, Hepatology, and Endocrinology, Hannover Medical School, Hannover, Germany
| | | |
Collapse
|
|
11
|
Temmesfeld-Wollbrück B, Brell B, zu Dohna C, Dorenberg M, Hocke AC, Martens H, Klar J, Suttorp N, Hippenstiel S. Adrenomedullin reduces intestinal epithelial permeability in vivo and in vitro. Am J Physiol Gastrointest Liver Physiol 2009; 297:G43-51. [PMID: 19423749 DOI: 10.1152/ajpgi.90532.2008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Leakage of the gut mucosal barrier in the critically ill patient may allow translocation of bacteria and their virulence factors, thereby perpetuating sepsis and inflammation. Present evidence suggests that adrenomedullin (AM) improves endothelial barrier function and stabilizes circulatory function in systemic inflammation. We tested the hypothesis that exogenously applied AM stabilizes gut epithelial barrier function. Infusion of Staphylococcus aureus alpha-toxin induced septic shock in rats. AM infusion in a therapeutic setting reduced translocation of labeled dextran from the gut into the systemic circulation in this model. AM also reduced alpha-toxin and hydrogen peroxide (H2O2)-related barrier disruption in Caco-2 cells in vitro and reduced H2O2-related rat colon barrier malfunction in Ussing chamber experiments. AM was shown to protect endothelial barrier function via cAMP elevation, but AM failed to induce cAMP accumulation in Caco-2 cells. cAMP is degraded via phosphodiesterases (PDE), and Caco-2 cells showed high activity of cAMP-degrading PDE3 and 4. However, AM failed to induce cAMP accumulation in Caco-2 cells even in the presence of sufficient PDE3/4 inhibition, whereas adenylyl cyclase activator forskolin induced strong cAMP elevation. Furthermore, PDE3/4 inhibition neither amplified AM-induced epithelial barrier stabilization nor affected AM cAMP-related rat colon short-circuit current, furthermore indicating that AM may act independently of cAMP in Caco-2 cells. Finally, experiments using chemical inhibitors indicated that PKC, phosphatidylinositide 3-kinase, p38, and ERK did not contribute to AM-related stabilization of barrier function in Caco-2 cells. In summary, during severe inflammation, elevated AM levels may substantially contribute to the stabilization of gut barrier function.
Collapse
Affiliation(s)
- Bettina Temmesfeld-Wollbrück
- Departments of Internal Medicine and Infectious Diseases, Charité-Universitätsmedizin Berlin, Berlin 13353, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
|
12
|
Genomic analysis of sulfasalazine effect in experimental colitis is consistent primarily with the modulation of NF-κB but not PPAR-γ signaling. Pharmacogenet Genomics 2009; 19:363-72. [DOI: 10.1097/fpc.0b013e3283299a73] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
|
13
|
Hirota CL, McKay DM. Loss of Ca-mediated ion transport during colitis correlates with reduced ion transport responses to a Ca-activated K channel opener. Br J Pharmacol 2009; 156:1085-97. [PMID: 19298254 DOI: 10.1111/j.1476-5381.2009.00122.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND AND PURPOSE Epithelial surface hydration is critical for proper gut function. However, colonic tissues from individuals with inflammatory bowel disease or animals with colitis are hyporesponsive to Cl(-) secretagogues. The Cl(-) secretory responses to the muscarinic receptor agonist bethanechol are virtually absent in colons of mice with dextran sodium sulphate (DSS)-induced colitis. Our aim was to define the mechanism underlying this cholinergic hyporesponsiveness. EXPERIMENTAL APPROACH Colitis was induced by 4% DSS water, given orally. Epithelial ion transport was measured in Ussing chambers. Colonic crypts were isolated and processed for mRNA expression via RT-PCR and protein expression via immunoblotting and immunolocalization. KEY RESULTS Expression of muscarinic M(3) receptors in colonic epithelium was not decreased during colitis. Short-circuit current (I(SC)) responses to other Ca(2+)-dependent secretagogues (histamine, thapsigargin, cyclopiazonic acid and calcium ionophore) were either absent or severely attenuated in colonic tissue from DSS-treated mice. mRNA levels of several ion transport molecules (a Ca(2+)-regulated Cl(-) channel, the intermediate-conductance Ca(2+)-activated K(+) channel, the cystic fibrosis transmembrane conductance regulator, the Na(+)/K(+)-ATPase pump or the Na(+)/K(+)/2Cl(-) co-transporter) were not reduced in colonic crypts from DSS-treated mice. However, protein expression of Na(+)/K(+)-ATPase alpha1 subunits was decreased twofold during colitis. Activation of Ca(2+)-activated K(+) channels increased I(SC) significantly less in DSS colons compared with control, as did the protein kinase C activator, phorbol 12-myristate 13-acetate. CONCLUSIONS AND IMPLICATIONS Decreased Na(+)/K(+)-ATPase expression probably contributes to overall epithelial hyporesponsiveness during colitis, while dysfunctional K(+) channels may account, at least partially, for lack of epithelial secretory responses to Ca(2+)-mediated secretagogues.
Collapse
Affiliation(s)
- Christina L Hirota
- Intestinal Disease Research Programme, Department of Pathology and Molecular Medicine, McMaster University, 3330 Hospital Drive Northwest, Calgary, Alberta, Canada.
| | | |
Collapse
|
|
14
|
Martínez-Augustin O, Romero-Calvo I, Suárez MD, Zarzuelo A, de Medina FS. Molecular bases of impaired water and ion movements in inflammatory bowel diseases. Inflamm Bowel Dis 2009; 15:114-27. [PMID: 18626965 DOI: 10.1002/ibd.20579] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The intestine is dedicated to the absorption of water and nutrients. Fine tuning of this process is necessary to maintain an adequate balance and inflammation disrupts the equilibrium. This review summarizes the current evidence in this field. Classical mechanisms proposed include alteration of epithelial integrity, augmented secretion, and reduced absorption. In addition, intestinal inflammation is associated with defects in epithelial barrier function. However, our understanding of the phenomenon has been complicated by the fact that ionic secretion is in fact diminished in vivo, even after inflammation has subsided. Inhibited ionic secretion can be reversed partially or totally in vitro by maneuvers such as blockade of inducible nitric oxide synthase or removal of the submucosal layer. Disturbances in ionic absorption are less well characterized but clearly involve both electroneutral and electrogenic Na(+) absorption. Altered ionic transport is associated with changes in the expression and function of the transporters, including the Na(+)/K(+) ATPase, the sodium/potassium/chloride cotransporter 1 (NKCC1), the sodium/hydrogen exchanger 3 (NHE3), and the epithelial sodium channel (ENaC), as well as to the modulation of intracellular signaling. Further investigation is needed in this area in order to provide an integrated paradigm of ionic transport in the inflamed intestine. In particular, we do not know exactly how diarrhea ensues in inflammation and, consequently, we do not have specific pharmacological tools to combat this condition effectively and without side effects. Moreover, whether transport disturbances are reversible independently of inflammatory control is unknown.
Collapse
Affiliation(s)
- Olga Martínez-Augustin
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
| | | | | | | | | |
Collapse
|
|
15
|
Martínez-Augustin O, Merlos M, Zarzuelo A, Suárez MD, de Medina FS. Disturbances in metabolic, transport and structural genes in experimental colonic inflammation in the rat: a longitudinal genomic analysis. BMC Genomics 2008; 9:490. [PMID: 18928539 PMCID: PMC2577662 DOI: 10.1186/1471-2164-9-490] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 10/17/2008] [Indexed: 12/26/2022] Open
Abstract
Background Trinitrobenzenesulphonic acid (TNBS) induced rat colitis is one of the most widely used models of inflammatory bowel disease (IBD), a condition whose aetiology and pathophysiology are incompletely understood. We have characterized this model at the genomic level using a longitudinal approach. Six control rats were compared with colitic animals at 2, 5, 7 and 14 days after TNBS administration (n = 3). The Affymetrix Rat Expression Array 230 2.0 system was used. Results TNBS-induced colitis had a profound impact on the gene expression profile, which was maximal 5 and 7 days post-induction. Most genes were affected at more than one time point. They were related to a number of biological functions, not only inflammation/immunity but also transport, metabolism, signal transduction, tissue remodeling and angiogenesis. Gene changes generally correlated with the severity of colitis. The results were successfully validated in a subset of genes by real-time PCR. Conclusion The TNBS model of rat colitis has been described in detail at the transcriptome level. The changes observed correlate with pathophysiological disturbances such as tissue remodelling and alterations in ion transport, which are characteristic of both this model and IBD.
Collapse
Affiliation(s)
- Olga Martínez-Augustin
- Department of Biochemistry and Molecular Biology II, CIBEREHD, School of Pharmacy, University of Granada, Granada, Spain.
| | | | | | | | | |
Collapse
|
|
16
|
Abstract
Bile acids (BAs) have a long established role in fat digestion in the intestine by acting as tensioactives, due to their amphipathic characteristics. BAs are reabsorbed very efficiently by the intestinal epithelium and recycled back to the liver via transport mechanisms that have been largely elucidated. The transport and synthesis of BAs are tightly regulated in part by specific plasma membrane receptors and nuclear receptors. In addition to their primary effect, BAs have been claimed to play a role in gastrointestinal cancer, intestinal inflammation and intestinal ionic transport. BAs are not equivalent in any of these biological activities, and structural requirements have been generally identified. In particular, some BAs may be useful for cancer chemoprevention and perhaps in inflammatory bowel disease, although further research is necessary in this field. This review covers the most recent developments in these aspects of BA intestinal biology.
Collapse
|
|
17
|
Chung HL, Yue GGL, To KF, Su YL, Huang Y, Ko WH. Effect of Scutellariae Radix extract on experimental dextran-sulfate sodium-induced colitis in rats. World J Gastroenterol 2007; 13:5605-11. [PMID: 17948935 PMCID: PMC4172740 DOI: 10.3748/wjg.v13.i42.5605] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
AIM: To investigate the effect of Scutellariae Radix extract (SRE) on ulcerative colitis (UC) in rats induced by dextran-sulfate sodium (DSS).
METHODS: Colitis was induced in male Sprague-Dawley (SD) rats (170-180 g) by 4% dextran sulfate sodium (DSS, wt/v; MW 54000) in drinking water for 8 d. The treated rats received 4% DSS and SRE orally (100 mg/kg per day). Control rats received either tap water or SRE only. Macroscopic assessment which included body weight changes, fecal occult blood and stool consistency were determined daily. At the appointed time, the rats were sacrificed and the entire colons were removed. The colon length and the myeloperoxidase (MPO) activity were measured. The severity of colitis was graded by morphological and histological assessments. The ion transport activity of the colonic mucosa was assessed by electrophysiological technique.
RESULTS: Rats treated with oral administration of 4% DSS regularly developed clinical and macroscopic signs of colitis. Treatment with SRE relieved the symptoms, including the reduction in body weight, shortening and ulceration of the colon. Administration of SRE also significantly reduced the histological damage induced by DSS. Moreover, the ISC responses of the colonic mucosa to forskolin were suppressed after the induction of colitis. The stimulated ion transport activity of DSS-rats treated with SRE displayed significant improvement in the secretory responsiveness.
CONCLUSION: SRE was effective in treating acute DSS-induced ulcerative colitis, as gauged by reduced clinical disease, improved macroscopic and histological damage scores, and enhanced recovery of normal colonic secretory function.
Collapse
|
|
18
|
Seidler U, Lenzen H, Cinar A, Tessema T, Bleich A, Riederer B. Molecular mechanisms of disturbed electrolyte transport in intestinal inflammation. Ann N Y Acad Sci 2006; 1072:262-75. [PMID: 17057206 DOI: 10.1196/annals.1326.024] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Diarrhea is the hallmark of both ulcerative colitis (UC) and Crohn's disease. Loss of resorptive area, destruction of epithelial cells, leaky tight junctions, and release of inflammatory mediators and products from immune cells that stimulate fluid secretion all have been implicated in the pathogenesis of inflammatory diarrhea. Very early studies in patients, however, have pinpointed the overwhelming transport abnormality in inflamed intestinal mucosa: a virtually complete loss of sodium resorptive capacity. Recently, tools have become available to study the molecular basis of disturbances in the major electrolyte transport systems during intestinal inflammation. This review gives a brief overview of the historical development of research related to electrolyte transport in inflammatory bowel disorders, focusing on the studies performed in humans, and highlights recent understanding of the molecular mechanisms that may help explain the origin of diarrhea in intestinal inflammation.
Collapse
Affiliation(s)
- Ursula Seidler
- Department of Gastroenterology, Hepatology, and Endocrinology, Hannover Medical School, Hannover, Germany.
| | | | | | | | | | | |
Collapse
|
|
19
|
Hirota CL, McKay DM. Cholinergic regulation of epithelial ion transport in the mammalian intestine. Br J Pharmacol 2006; 149:463-79. [PMID: 16981004 PMCID: PMC2014671 DOI: 10.1038/sj.bjp.0706889] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Acetylcholine (ACh) is critical in controlling epithelial ion transport and hence water movements for gut hydration. Here we review the mechanism of cholinergic control of epithelial ion transport across the mammalian intestine. The cholinergic nervous system affects basal ion flux and can evoke increased active ion transport events. Most studies rely on measuring increases in short-circuit current (ISC = active ion transport) evoked by adding ACh or cholinomimetics to intestinal tissue mounted in Ussing chambers. Despite subtle species and gut regional differences, most data indicate that, under normal circumstances, the effect of ACh on intestinal ion transport is mainly an increase in Cl- secretion due to interaction with epithelial M3 muscarinic ACh receptors (mAChRs) and, to a lesser extent, neuronal M1 mAChRs; however, AChR pharmacology has been plagued by a lack of good receptor subtype-selective compounds. Mice lacking M3 mAChRs display intact cholinergically-mediated intestinal ion transport, suggesting a possible compensatory mechanism. Inflamed tissues often display perturbations in the enteric cholinergic system and reduced intestinal ion transport responses to cholinomimetics. The mechanism(s) underlying this hyporesponsiveness are not fully defined. Inflammation-evoked loss of mAChR-mediated control of epithelial ion transport in the mouse reveals a role for neuronal nicotinic AChRs, representing a hitherto unappreciated braking system to limit ACh-evoked Cl- secretion. We suggest that: i) pharmacological analyses should be supported by the use of more selective compounds and supplemented with molecular biology techniques targeting specific ACh receptors and signalling molecules, and ii) assessment of ion transport in normal tissue must be complemented with investigations of tissues from patients or animals with intestinal disease to reveal control mechanisms that may go undetected by focusing on healthy tissue only.
Collapse
Affiliation(s)
- C L Hirota
- Department Physiology & Biophysics, University of Calgary, Calgary, AB, Canada.
| | | |
Collapse
|
|
20
|
Daddaoua A, Puerta V, Zarzuelo A, Suárez MD, Sánchez de Medina F, Martínez-Augustin O. Bovine glycomacropeptide is anti-inflammatory in rats with hapten-induced colitis. J Nutr 2005; 135:1164-70. [PMID: 15867298 DOI: 10.1093/jn/135.5.1164] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Milk kappa-casein-derived glycomacropeptide has immunomodulatory and bacterial toxin binding effects. The intestinal anti-inflammatory activity of glycomacropeptide was assessed in trinitrobenzenesulfonic acid-induced colitis in rats. Rats were administered glycomacropeptide daily starting either 2 d before (pretreatment) or 3 h after (post-treatment) colitis induction. Pretreatment with glycomacropeptide had a dose-dependent anti-inflammatory effect, characterized by lower body weight loss, decreased anorexia (57%), colonic damage (65%), and weight to length ratio (32%), as well as a reduction in colonic alkaline phosphatase activity (42%) and interleukin 1, trefoil factor 3, and inducible nitric oxide synthase mRNA levels (P < 0.05). The mechanism of action of glycomacropeptide is unknown but is consistent with an inhibition of the activation of immune cells. The magnitude of the anti-inflammatory effect was generally comparable to that of sulfasalazine, an established drug used in the treatment of inflammatory bowel disease. Bovine glycomacropeptide may play a role in the management of patients with inflammatory bowel disease.
Collapse
Affiliation(s)
- Abdelali Daddaoua
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Granada, Spain
| | | | | | | | | | | |
Collapse
|
|
21
|
Pérez-Navarro R, Martínez-Augustin O, Ballester I, Zarzuelo A, Sánchez de Medina F. Experimental inflammation of the rat distal colon inhibits ion secretion in the proximal colon by affecting the enteric nervous system. Naunyn Schmiedebergs Arch Pharmacol 2005; 371:114-21. [PMID: 15717198 DOI: 10.1007/s00210-005-1023-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Accepted: 01/04/2005] [Indexed: 11/24/2022]
Abstract
Intestinal inflammation causes hyporesponsiveness of the inflamed tissue to secretagogues but little is known about the behaviour of the areas proximal to the site of inflammation. We studied the responses of the proximal segment of the colon to carbachol, histamine, isobutylmethylxanthine (IBMX) and vasoactive intestinal peptide (VIP) in rats with trinitrobenzenesulphonic acid (TNBS)-induced, chronic inflammation of the distal colon. Macroscopic and biochemical analysis ruled out the presence of inflammation in the proximal colon. When mounted in Ussing chambers under voltage-clamp conditions, basal transport and conductance were not affected. However, the maximum response in the concentration/response curves (short-circuit current) for carbachol and histamine was reduced in TNBS-treated rats, without changes in the EC(50). This effect corresponded to reduced chloride secretion, as demonstrated by ion substitution experiments. The responses to IBMX and VIP were virtually unaffected. The inhibitory effect was abolished by pretreatment with the neural blockers tetrodotoxin and lidocaine but not indomethacin, suggesting that the enteric nervous system is responsible for the inhibition. In conclusion, chronic distal inflammation of the distal colon results in inhibition of calcium-dependent secretion in the proximal colon via a reduction of the contribution of the enteric nervous system.
Collapse
Affiliation(s)
- R Pérez-Navarro
- Department of Pharmacology, School of Pharmacy, University of Granada, Campus de Cartuja s/n, 18071 Granada, Spain
| | | | | | | | | |
Collapse
|
|
22
|
Abstract
Inflammation of the bowel causes structural and functional changes to the enteric nervous system (ENS). While morphological alterations to the ENS are evident in some inflammatory conditions, it appears that relatively subtle modifications to the neurophysiology of enteric microcircuits may play a role in gastrointestinal (GI) dysfunction. These include changes to the excitability and synaptic properties of enteric neurones. The response of the ENS to inflammation varies according to the site and type of inflammation, with the functional consequences depending on the nature of the inflammatory stimulus. It has become clear that inflammation at one site can produce changes that occur at remotes sites in the GI tract. Immunohistochemical data from patients with inflammatory bowel disease (IBD) and animal models indicate that inflammation alters the neurochemical content of some functional classes of enteric neurones. A growing body of evidence supports an active role for enteric glia in neuronal and neuroimmune communication in the GI tract, particularly during inflammation. In conclusion, plasticity of the ENS is a feature of intestinal inflammation. Elucidation of the mechanisms whereby inflammation alters enteric neural control of GI functions may lead to novel treatments for IBD.
Collapse
Affiliation(s)
- A E Lomax
- Department of Physiology and Biophysics, Gastrointestinal, Neuroscience and Mucosal Inflammation Research Groups, University of Calgary, Calgary, Alberta, Canada
| | | | | |
Collapse
|
|
23
|
Pérez-Navarro R, Ballester I, Zarzuelo A, Sánchez de Medina F. Disturbances in epithelial ionic secretion in different experimental models of colitis. Life Sci 2005; 76:1489-501. [PMID: 15680313 DOI: 10.1016/j.lfs.2004.09.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Accepted: 09/08/2004] [Indexed: 10/26/2022]
Abstract
This paper studies the disturbances in ionic secretion in the colon of rats with different models of acute and chronic colitis measured as changes in short-circuit current. The aim was to verify whether the reported inhibition of basal and stimulated secretion in the trinitrobenzene sulfonic acid and mytomicin C models are applicable to experimental colitis as such. All models showed remarkable similarity in ion transport as determined in Ussing chambers, with downregulated basal as well as carbachol evoked secretion. The EC(50) of carbachol was unchanged in all cases. Iodoacetamide and oxazolone colitis models were notable exceptions in that the dose response curves for carbachol were unaltered compared to controls. The reason is unclear but seems to be unrelated to either interferon gamma or interleukin 4 levels or to the severity of the inflammatory response.
Collapse
Affiliation(s)
- Rubén Pérez-Navarro
- Department of Pharmacology, School of Pharmacy, University of Granada, Campus de Cartuja s/n, 18071 Granada, Spain.
| | | | | | | |
Collapse
|
|
24
|
Sánchez de Medina F, Martínez-Augustin O, González R, Ballester I, Nieto A, Gálvez J, Zarzuelo A. Induction of alkaline phosphatase in the inflamed intestine: a novel pharmacological target for inflammatory bowel disease. Biochem Pharmacol 2004; 68:2317-26. [PMID: 15548378 DOI: 10.1016/j.bcp.2004.07.045] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2004] [Accepted: 07/07/2004] [Indexed: 12/22/2022]
Abstract
This study demonstrates the upregulation of alkaline phosphatase and the mechanisms involved in experimental colitis. All models of ileal and colonic inflammation examined, which were characterized by significant oxidative stress and neutrophil infiltration, resulted in an increase in alkaline phosphatase activity which was attributable to both epithelial cells and cells of the lamina propria, mainly leukocytes. The increase in alkaline phosphatase sensitivity to the inhibitors levamisole and homoarginine, together with changes in the apparent molecular size and in the sialization of the enzyme, indicated a change in the isoform expressed. An increase in tissue non-specific alkaline phosphatase expression was observed by Western blotting. Treatment with the bone/kidney alkaline phosphatase inhibitor levamisole or a monoclonal antibody resulted in significant protection from colonic inflammation. Taken together, these results indicate that the kidney isoform is a marker of intestinal inflammation and that it might even constitute a target for pharmacological intervention.
Collapse
Affiliation(s)
- Fermín Sánchez de Medina
- Department of Pharmacology, School of Pharmacy, University of Granada, Campus de Cartuja s/n, 18071 Granada, Spain.
| | | | | | | | | | | | | |
Collapse
|
|
25
|
Green CL, Ho W, Sharkey KA, McKay DM. Dextran sodium sulfate-induced colitis reveals nicotinic modulation of ion transport via iNOS-derived NO. Am J Physiol Gastrointest Liver Physiol 2004; 287:G706-14. [PMID: 15087277 DOI: 10.1152/ajpgi.00076.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In normal colon, ACh elicits a luminally directed Cl- efflux from enterocytes via activation of muscarinic receptors. In contrast, in the murine model of dextran sodium sulfate (DSS)-induced colitis, an inhibitory cholinergic ion transport event due to nicotinic receptor activation has been identified. The absence of nicotinic receptors on enteric epithelia and the ability of nitric oxide (NO) to modulate ion transport led us to hypothesize that NO mediated the cholinergic nicotinic receptor-induced changes in ion transport. Midportions of colon from control and DSS-treated mice were examined for inducible NO synthase (iNOS) expression by RT-PCR and immunofluorescence or mounted in Ussing chambers for assessment of cholinergic-evoked changes in ion transport (i.e., short-circuit current) with or without pretreatment with pharmacological inhibitors of NO production. iNOS mRNA and protein levels were increased throughout the tissue from DSS-treated mice and, notably, in the myenteric plexus, where the majority of iNOS immunoreactivity colocalized with the enteric glial cell marker glial fibrillary acidic protein. The drop in short-circuit current evoked by the cholinomimetic carbachol in tissue from DSS-treated mice was prevented by selective inhibitors of iNOS activity [N6-(1-iminoethyl)-lysine HCl and N-[3-(aminomethyl)benzyl]acetamidine] or an NO scavenger [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide] or by removal of the myenteric plexus. Thus, in this model of colitis, a "switch" occurs from muscarinic to nicotinic receptor-dominated control of cholinergic ion transport. The data indicate a novel pathway involving activation of nicotinic receptors on myenteric neurons, resulting in release of NO from neurons or enteric glia and, ultimately, a dampening of stimulated epithelial Cl- secretion that would reduce secretory diarrhea.
Collapse
Affiliation(s)
- Christina L Green
- Intestinal Disease Research Programme, McMaster University, Hamilton, Ontario, Canada L8N 3Z5
| | | | | | | |
Collapse
|
|
26
|
González R, Sánchez de Medina F, Martínez-Augustin O, Nieto A, Gálvez J, Risco S, Zarzuelo A. Anti-inflammatory effect of diosmectite in hapten-induced colitis in the rat. Br J Pharmacol 2004; 141:951-60. [PMID: 14993105 PMCID: PMC1574279 DOI: 10.1038/sj.bjp.0705710] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
1. Diosmectite is a natural silicate effectively used in the treatment of infectious diarrhoea. Its antidiarrhoeal properties involve adsorption of toxins and bacteria and modifications of the rheological characteristics of gastrointestinal mucus. Hence, the aim of this study was to test the intestinal anti-inflammatory activity of diosmectite. 2. Diosmectite (500 mg x kg(-1) day(-1), p.o.) was administered as a post-treatment to rats with chronic trinitrobenzene sulphonic acid colitis. Colonic status was checked 1 and 2 weeks after colitis induction by macroscopic, histological and biochemical examination. 3. Diosmectite post-treatment resulted in amelioration of the morphological signs (intestinal weight, macroscopic damage, necrosed area, histology) and biochemical markers (myeloperoxidase activity, glutathione levels, MUC2 expression, inducible nitric oxide synthase and interleukin-1beta (IL-1beta) and leukotriene B(4) synthesis), as well as in the reduction of the severity of diarrhoea. The effect of the clay was comparable to that of sulphasalazine (50 mg x kg(-1) day(-1)). 4. 5. Diosmectite exhibited a dose-dependent capacity to adsorb proteins in vitro as well as a dose-dependent inhibitory effect on the basolateral secretion of IL-8 by lipopolysaccharide (LPS)-stimulated HT29 cells. Diosmectite had a dose-dependent inhibitory effect on IL-1beta production by LPS-stimulated THP-1 cells. 6. The effect of diosmectite on MUC2 was post-transcriptional, since mRNA levels were unaffected. However, diosmectite is able to upregulate MUC2 mRNA levels in HT29-MTX cells. 7. Diosmectite has anti-inflammatory activity administered as a post-treatment. Possible mechanisms include adsorption of luminal antigens, increase of colonic mucin levels and possibly a direct modulatory action of cytokine production by mucosal cells.
Collapse
Affiliation(s)
- Raquel González
- Departments of Pharmacology and Biochemistry and Molecular Biology, School of Pharmacy, University of Granada, Spain
| | - Fermin Sánchez de Medina
- Departments of Pharmacology and Biochemistry and Molecular Biology, School of Pharmacy, University of Granada, Spain
- Author for correspondence:
| | - Olga Martínez-Augustin
- Departments of Pharmacology and Biochemistry and Molecular Biology, School of Pharmacy, University of Granada, Spain
| | - Ana Nieto
- Department of Animal Medicine and Surgery, School of Veterinary, Universidad Complutense, Madrid, Spain
| | - Julio Gálvez
- Departments of Pharmacology and Biochemistry and Molecular Biology, School of Pharmacy, University of Granada, Spain
| | - Severiano Risco
- Departments of Pharmacology and Biochemistry and Molecular Biology, School of Pharmacy, University of Granada, Spain
| | - Antonio Zarzuelo
- Departments of Pharmacology and Biochemistry and Molecular Biology, School of Pharmacy, University of Granada, Spain
| |
Collapse
|
|
27
|
Walker J, Jijon HB, Churchill T, Kulka M, Madsen KL. Activation of AMP-activated protein kinase reduces cAMP-mediated epithelial chloride secretion. Am J Physiol Gastrointest Liver Physiol 2003; 285:G850-60. [PMID: 12869384 DOI: 10.1152/ajpgi.00077.2003] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
AMP-activated protein kinase (AMPK) is activated in response to fluctuations in cellular energy status caused by oxidative stress. One of its targets is the cystic fibrosis transmembrane conductance regulator (CFTR), which is the predominant Cl- secretory channel in colonic tissue. The aim of this study was to determine the role of AMPK in the modulation of colonic chloride secretion under conditions of oxidative stress and chronic inflammation. Chloride secretion and AMPK activity were examined in colonic tissue from adult IL-10-deficient and wild-type 129 Sv/Ev mice in the presence and absence of pharmacological AMPK inhibitors and activators, respectively. Apical levels of CFTR were measured in brush-border membrane vesicles. Cell culture studies in human colonic T84 monolayers examined the effect of hydrogen peroxide and pharmacological activation of AMPK on forskolin-stimulated chloride secretion. Inflamed colons from IL-10-deficient mice exhibited hyporesponsiveness to forskolin stimulation in association with reductions in surface CFTR expression and increased AMPK activity. Inhibition of AMPK restored tissue responsiveness to forskolin, whereas stimulation of AMPK with 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR) induced tissue hyporesponsivness in wild-type mice. T84 cells exposed to hydrogen peroxide demonstrated a time-dependent increase in AMPK activity and reduction of forskolin-stimulated chloride secretion. Inhibition of AMPK prevented the reduction in chloride secretion. Treatment of cells with the AMPK activator, AICAR, resulted in a decreased chloride secretion. In conclusion, AMPK activation is linked with reductions in cAMP-mediated epithelial chloride flux and may be a contributing factor to the hyporesponsiveness seen under conditions of chronic inflammation.
Collapse
Affiliation(s)
- John Walker
- Univ. of Alberta, 6146 Dentistry Pharmacy Bldg., Edmonton, AB, Canada T6G 2C2
| | | | | | | | | |
Collapse
|
|
28
|
Morel E, Dublineau I, Griffiths NM. Effect of radiation on cAMP, cGMP and Ca(2+)(i) pathways and their interactions in rat distal colon. Radiat Res 2003; 160:263-72. [PMID: 12926985 DOI: 10.1667/rr3041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The secretory response implicated in the intestinal response to luminal attack is altered by radiation. The cAMP, cGMP and Ca(2+)(i) pathways leading to secretion as well as the interactions between the cAMP pathway and the cGMP or Ca(2+)(i) pathway were studied in the rat distal colon 4 days after a 9-Gy abdominal X irradiation, when modifications mainly occurred. The secretory response in Ussing chambers and cAMP and cGMP accumulation in single isolated crypts were measured. The muscarinic receptor characteristics were determined in mucosal membrane preparations. The secretory response by the cAMP pathway (stimulated by vasoactive intestinal peptide or forskolin) and the cAMP accumulation in crypts were decreased (P < 0.05) after irradiation. The weak secretory response induced by the cGMP pathway (stimulated by nitric oxide or guanylin) was unaltered by radiation, and the small amount of cGMP determined in isolated crypts from the control group became undetectable in the irradiated group. Inducible NOS was not involved in the hyporesponsiveness to VIP after irradiation (there was no effect of an iNOS inhibitor). The secretory response by the Ca(2+)(i) pathway (stimulated by carbachol) was unaffected despite a decreased number and increased affinity of muscarinic receptors. The non-additivity of VIP and carbachol co-stimulated responses was unmodified. In contrast, VIP and SNP co-stimulation showed that NO enhanced the radiation-induced hyporesponsiveness to VIP through a reduced accumulation of cAMP in crypts. This study provides further understanding of the effect of ionizing radiation on the intracellular signaling pathways.
Collapse
Affiliation(s)
- E Morel
- Institut de Radioprotection et de Sûreté Nucléaire, Département de Protection de la santé de l'Homme et de Dosimétrie, Section Autonome de Radiobiologie Appliquée à la Médecine, IRSN, Fontenay aux Roses Cedex, France
| | | | | |
Collapse
|