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Chronic Experimental Model of TNBS-Induced Colitis to Study Inflammatory Bowel Disease. Int J Mol Sci 2022; 23:ijms23094739. [PMID: 35563130 PMCID: PMC9105049 DOI: 10.3390/ijms23094739] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/21/2022] [Accepted: 04/24/2022] [Indexed: 01/14/2023] Open
Abstract
Background: Inflammatory bowel disease (IBD) is a world healthcare problem. In order to evaluate the effect of new pharmacological approaches for IBD, we aim to develop and validate chronic trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. Methods: Experimental colitis was induced by the rectal administration of multiple doses of TNBS in female CD-1 mice. The protocol was performed with six experimental groups, depending on the TNBS administration frequency, and two control groups (sham and ethanol groups). Results: The survival rate was 73.3% in the first three weeks and, from week 4 until the end of the experimental protocol, the mice’s survival remained unaltered at 70.9%. Fecal hemoglobin presented a progressive increase until week 4 (5.8 ± 0.3 µmol Hg/g feces, p < 0.0001) compared with the ethanol group, with no statistical differences to week 6. The highest level of tumor necrosis factor-α was observed on week 3; however, after week 4, a slight decrease in tumor necrosis factor-α concentration was verified, and the level was maintained until week 6 (71.3 ± 3.3 pg/mL and 72.7 ± 3.6 pg/mL, respectively). Conclusions: These findings allowed the verification of a stable pattern of clinical and inflammation signs after week 4, suggesting that the chronic model of TNBS-induced colitis develops in 4 weeks.
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Robinson AM, Sakkal S, Park A, Jovanovska V, Payne N, Carbone SE, Miller S, Bornstein JC, Bernard C, Boyd R, Nurgali K. Mesenchymal stem cells and conditioned medium avert enteric neuropathy and colon dysfunction in guinea pig TNBS-induced colitis. Am J Physiol Gastrointest Liver Physiol 2014; 307:G1115-29. [PMID: 25301186 DOI: 10.1152/ajpgi.00174.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Damage to the enteric nervous system (ENS) associated with intestinal inflammation may underlie persistent alterations to gut functions, suggesting that enteric neurons are viable targets for novel therapies. Mesenchymal stem cells (MSCs) offer therapeutic benefits for attenuation of neurodegenerative diseases by homing to areas of inflammation and exhibiting neuroprotective, anti-inflammatory, and immunomodulatory properties. In culture, MSCs release soluble bioactive factors promoting neuronal survival and suppressing inflammation suggesting that MSC-conditioned medium (CM) provides essential factors to repair damaged tissues. We investigated whether MSC and CM treatments administered by enema attenuate 2,4,6-trinitrobenzene-sulfonic acid (TNBS)-induced enteric neuropathy and motility dysfunction in the guinea pig colon. Guinea pigs were randomly assigned to experimental groups and received a single application of TNBS (30 mg/kg) followed by 1 × 10(6) human bone marrow-derived MSCs, 300 μl CM, or 300 μl unconditioned medium 3 h later. After 7 days, the effect of these treatments on enteric neurons was assessed by histological, immunohistochemical, and motility analyses. MSC and CM treatments prevented inflammation-associated weight loss and gross morphological damage in the colon; decreased the quantity of immune infiltrate in the colonic wall (P < 0.01) and at the level of the myenteric ganglia (P < 0.001); prevented loss of myenteric neurons (P < 0.05) and damage to nerve processes, changes in ChAT, and nNOS immunoreactivity (P < 0.05); and alleviated inflammation-induced colonic dysmotility (contraction speed; P < 0.001, contractions/min; P < 0.05). These results provide strong evidence that both MSC and CM treatments can effectively prevent damage to the ENS and alleviate gut dysfunction caused by TNBS-induced colitis.
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Affiliation(s)
- Ainsley M Robinson
- College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Samy Sakkal
- College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Anthony Park
- Department of Anatomy and Neuroscience, Monash University, Melbourne, Australia
| | | | - Natalie Payne
- Department of Anatomy and Neuroscience, Monash University, Melbourne, Australia; Australian Regenerative Medicine Institute, Monash University, Melbourne, Australia; and
| | - Simona E Carbone
- College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Sarah Miller
- College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Joel C Bornstein
- Department of Physiology, Melbourne University, Melbourne, Australia
| | - Claude Bernard
- Department of Anatomy and Neuroscience, Monash University, Melbourne, Australia; Australian Regenerative Medicine Institute, Monash University, Melbourne, Australia; and
| | - Richard Boyd
- Department of Anatomy and Neuroscience, Monash University, Melbourne, Australia
| | - Kulmira Nurgali
- College of Health and Biomedicine, Victoria University, Melbourne, Australia;
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Glauben R, Sonnenberg E, Wetzel M, Mascagni P, Siegmund B. Histone deacetylase inhibitors modulate interleukin 6-dependent CD4+ T cell polarization in vitro and in vivo. J Biol Chem 2014; 289:6142-51. [PMID: 24421314 DOI: 10.1074/jbc.m113.517599] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Histone deacetylase (HDAC) inhibitors have been associated primarily with an anti-proliferative effect in vitro and in vivo. Recent data provide evidence for an anti-inflammatory potency of HDAC inhibitors in models of experimental colitis. Because the balance of T cell subpopulations is critical for the balance of the mucosal immune system, this study explores the regulatory potency of HDAC inhibitors on T cell polarization as a mechanistic explanation for the observed anti-inflammatory effects. Although HDAC inhibition suppressed the polarization toward the pro-inflammatory T helper 17 (Th17) cells, it enhanced forkhead box P3 (FoxP3)(+) regulatory T cell polarization in vitro and in vivo at the site of inflammation in the lamina propria. This was paralleled by a down-regulation of the interleukin 6 receptor (IL-6R) on naïve CD4(+) T cells on the mRNA as well as on the protein level and changes in the chromatin acetylation at the IL6R gene and its promoter. Downstream of the IL-6R, HDAC inhibition was followed by a decrease in STAT3 phosphorylation as well as retinoic acid receptor-related orphan receptor γT (RORγT) expression, thus identifying the IL-6/STAT3/IL-17 pathway as an important target of HDAC inhibitors. These results directly translated to experimental colitis, where IL-6R expression was suppressed in naïve T cells, paralleled by a significant reduction of Th17 cells in the lamina propria of ITF2357-treated animals, resulting in the amelioration of disease. This study indicates that, in experimental colitis, inhibition of HDAC exerts an anti-inflammatory potency by directing T helper cell polarization via targeting the IL-6 pathway.
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Affiliation(s)
- Rainer Glauben
- From the Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Medical Department I, 12200 Berlin, Germany and
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Motavallian A, Minaiyan M, Rabbani M, Andalib S, Mahzouni P. Involvement of 5HT3 Receptors in Anti-Inflammatory Effects of Tropisetron on Experimental TNBS-Induced Colitis in Rat. BIOIMPACTS : BI 2013; 3:169-76. [PMID: 24455480 DOI: 10.5681/bi.2013.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/12/2013] [Accepted: 05/08/2013] [Indexed: 01/15/2023]
Abstract
INTRODUCTION There is a pressing need for research leading to the development of new effective drugs with lower side effects and more efficacy for treating inflammatory bowel disease (IBD). The analgesic and anti-inflammatory properties of 5-Hydroxytryptamine (5-HT)-3 receptor antagonists have been shown in in vivo and in vitro studies. The present study was designed to investigate the effects of tropisetron, a 5-HT3 receptor antagonist, on an immune-based animal model of IBD. METHODS In the present study, the trinitrobenzenesulfonic acid (TNBS) model of colitis in the rat was used. Two hours after induction of colitis in rats, tropisetron (2 mg/kg), dexamethasone (1 mg/kg), meta-chlorophenylbiguanide (mCPBG, 5 mg/kg), a 5-HT3 receptor agonist, or tropisetron + mCPBG were intraperitoneally (i.p.) administrated for 6 days. Animals were then sacrificed; macroscopic, histological, biochemical (myeloperoxidase [MPO]) assessments and ELISA test (tumor necrosis factor-alpha, interleukin-6 and interleukin-1 beta) were performed on distal colon samples. RESULTS Tropisetron or dexamethasone treatment significantly reduced macroscopic and microscopic colonic damages. In addition, a significant reduction in MPO activity and colonic levels of inflammatory cytokines was seen. The beneficial effects of tropisetron were antagonized by concurrent administration of mCPBG. CONCLUSION The present study indicates that the protective effects of tropisetron on TNBS-induced colitis can be mediated by 5-HT3 receptors.
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Affiliation(s)
- Azadeh Motavallian
- Department of Pharmacology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Mohsen Minaiyan
- Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad Rabbani
- Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Sasan Andalib
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Parvin Mahzouni
- Department of Clinical Pathology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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Lung and intestine: a specific link in an ulcerative colitis rat model. Gastroenterol Res Pract 2013; 2013:124530. [PMID: 23606829 PMCID: PMC3625615 DOI: 10.1155/2013/124530] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 03/02/2013] [Accepted: 03/02/2013] [Indexed: 02/07/2023] Open
Abstract
Background. To investigate the link and mechanisms between intestine and lung in the ulcerative colitis (UC) rat model. Materials and Methods. We used the UC rat model by immunological sensitization combined with local 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) in 50% ethanol enema, observed dynamically animal general state and body weight, examined the histological and functional changes in the colon, lung, liver, and kidney tissues, and detected microvascular endothelium response towards inflammation characterized with the expression of iNOS, TXB2, P-selectin, ICAM-1, and vascular endothelial growth factor A (VEGF-A) in the colon and lung tissue. Results. Pulmonary function results suggested ventilator disorder, and pathological findings showed interstitial pneumonia. There were no significant changes in the liver and kidney function and histopathology. The colon and lung tissue iNOS, TXB2, P-selectin, ICAM-1, and VEGF-A expression of the model rats was significantly higher than the normal rats at both time points. Conclusions. Our study is the first to demonstrate the close association between the large intestine and lung in the immune-TNBS-ethanol-induced UC rat model. Different organs and tissues with the same embryonic origin may share the same pathological specificities in a disease. The present study provided a new way of thinking for pathological changes in clinical complex diseases manifested with multiorgan damage.
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Zhao J, Zepp J, Bulek K, Li X. SIGIRR, a negative regulator of colon tumorigenesis. ACTA ACUST UNITED AC 2012; 8:e63-e69. [PMID: 22529873 DOI: 10.1016/j.ddmec.2012.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Inappropriate activation of the Toll-IL-1R (TL-IL-1) signaling by commensal bacteria contributes to the pathogenesis of inflammatory bowel diseases and colitis-associated cancer. Recent studies have identified SIGIRR as a negative regulator of TL-IL-1 signaling. It dampens intestinal inflammation and tumorigenesis in the colon. In this review, we will discuss the role of SIGIRR in different cell types and the mechanisms underlying its tumor suppressor function.
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Affiliation(s)
- Junjie Zhao
- Department of Immunology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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Reinecke K, Eminel S, Dierck F, Roessner W, Kersting S, Chromik AM, Gavrilova O, Laukevicience A, Leuschner I, Waetzig V, Rosenstiel P, Herdegen T, Sina C. The JNK inhibitor XG-102 protects against TNBS-induced colitis. PLoS One 2012; 7:e30985. [PMID: 22427801 PMCID: PMC3302790 DOI: 10.1371/journal.pone.0030985] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 12/30/2011] [Indexed: 12/19/2022] Open
Abstract
The c-Jun N-terminal kinase (JNK)-inhibiting peptide D-JNKI-1, syn. XG-102 was tested for its therapeutic potential in acute inflammatory bowel disease (IBD) in mice. Rectal instillation of the chemical irritant trinitrobenzene sulfonic acid (TNBS) provoked a dramatic acute inflammation in the colon of 7–9 weeks old mice. Coincident subcutaneous application of 100 µg/kg XG-102 significantly reduced the loss of body weight, rectal bleeding and diarrhoea. After 72 h, the end of the study, the colon was removed and immuno-histochemically analysed. XG-102 significantly reduced (i) pathological changes such as ulceration or crypt deformation, (ii) immune cell pathology such as infiltration and presence of CD3- and CD68-positive cells, (iii) the production of tumor necrosis factor (TNF)-α in colon tissue cultures from TNBS-treated mice, (iv) expression of Bim, Bax, FasL, p53, and activation of caspase 3, (v) complexation of JNK2 and Bim, and (vi) expression and activation of the JNK substrate and transcription factor c-Jun. A single application of subcutaneous XG-102 was at least as effective or even better depending on the outcome parameter as the daily oral application of sulfasalazine used for treatment of IBD. The successful and substantial reduction of the severe, TNBS-evoked intestinal damages and clinical symptoms render the JNK-inhibiting peptide XG-102 a powerful therapeutic principle of IBD.
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Affiliation(s)
- Kirstin Reinecke
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Sevgi Eminel
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | | | - Wibke Roessner
- Pharmaceutical Institute, University of Kiel, Kiel, Germany
| | - Sabine Kersting
- Department of Visceral and General Surgery, St. Josef Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Ansgar Michael Chromik
- Department of Visceral and General Surgery, St. Josef Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Olga Gavrilova
- Institute for Clinical Molecular Biology, University of Kiel, University Hospital Schleswig-Holstein, Kiel, Campus Kiel, Kiel, Germany
| | - Ale Laukevicience
- Department of Physiology, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Ivo Leuschner
- Institute of Pathology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Vicki Waetzig
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Philip Rosenstiel
- Institute for Clinical Molecular Biology, University of Kiel, University Hospital Schleswig-Holstein, Kiel, Campus Kiel, Kiel, Germany
| | - Thomas Herdegen
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
- * E-mail:
| | - Christian Sina
- Institute for Clinical Molecular Biology, University of Kiel, University Hospital Schleswig-Holstein, Kiel, Campus Kiel, Kiel, Germany
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Motavallian A, Minaiyan M, Rabbani M, Mahzouni P, Andalib S, Abed A, Babavalian MR. Does Cisapride, as a 5HT(4) Receptor Agonist, Aggravate the Severity of TNBS-Induced Colitis in Rat? Gastroenterol Res Pract 2012; 2012:362536. [PMID: 22888336 PMCID: PMC3408677 DOI: 10.1155/2012/362536] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 06/09/2012] [Accepted: 06/09/2012] [Indexed: 12/11/2022] Open
Abstract
There is a pressing need for research that will lead to the reveal of targets designed to analyse the possible pathways for the treatment of IBD. Because of the probable involvement of serotonin in inflammatory conditions of intestine and the important role of 5HT(4) receptors in GI function, the investigation of the role of 5HT(4) receptors in the pathogenesis of IBD will be interesting. The aim of this study was to investigate the effects of cisapride, a 5HT(4) receptor agonist, in trinitrobenzenesulfonic-acid-(TNBS) induced rat colitis. Two hours subsequent to induction of colitis using TNBS in rats, cisapride (2 mg/kg, intraperitoneally (i.p); 4 mg/kg, orally (p.o)) and dexamethasone (1 mg/kg, i.p; 2 mg/kg, p.o) were administrated for 6 days. Animals were thereafter euthanized; macroscopic, histological, and biochemical assessments and ELISA test were carried out on distal colon samples. Our data showed that dexamethasone treatment (i.p, p.o) significantly decreased macroscopic and microscopic damage and also biochemical markers, but there were no significant differences in aforementioned parameters between cisapride (i.p or p.o) and TNBS-treated rats. It can be deduced that because the severity of colitis produced by TNBS is massive (through various pathways), cisapride could not bring about more colitis damages through 5HT(4) receptors. Based on the present study further researches are required for investigating the exact roles of 5HT(4) receptors in the pathogenesis of ulcerative colitis.
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Affiliation(s)
- Azadeh Motavallian
- 1Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan 8146-73461, Iran
| | - Mohsen Minaiyan
- 1Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan 8146-73461, Iran
- 2Department of Pharmacology and Toxicology, Faculty of Pharmacy, Isfahan University of Medical Sciences, Isfahan 8146-73461, Iran
- *Mohsen Minaiyan:
| | - Mohammad Rabbani
- 1Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan 8146-73461, Iran
- 2Department of Pharmacology and Toxicology, Faculty of Pharmacy, Isfahan University of Medical Sciences, Isfahan 8146-73461, Iran
| | - Parvin Mahzouni
- 3Department of Clinical Pathology, School of Medicine, Isfahan University of Medical Sciences, Isfahan 8146-73461, Iran
| | - Sasan Andalib
- 4Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz 8146-73461, Iran
| | - Alireza Abed
- 1Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan 8146-73461, Iran
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Schmidt D, Reber SO, Botteron C, Barth T, Peterlik D, Uschold N, Männel DN, Lechner A. Chronic psychosocial stress promotes systemic immune activation and the development of inflammatory Th cell responses. Brain Behav Immun 2010; 24:1097-104. [PMID: 20451603 DOI: 10.1016/j.bbi.2010.04.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 04/28/2010] [Accepted: 04/28/2010] [Indexed: 11/17/2022] Open
Abstract
Recent studies indicate that chronic psychosocial stress favors the development of generalized immune dysfunction. During stressor exposure neuroendocrine factors affect numbers and functionality of leukocytes. However, the exact mechanisms leading to systemic changes in immune functions during stress are still not clear. During chronic subordinate colony housing, a model of chronic psychosocial stress, mice developed spontaneous colonic inflammation. Decreased glucocorticoid signaling, induced by a combination of adrenal insufficiency and glucocorticoid resistance, was thought to prevent tempering of local immune cells, and to promote tissue inflammation. In this study we investigated changes in the systemic immune status after chronic subordinate colony housing and analyzed potential mechanisms underlying those alterations. Analysis of T helper cell subsets in peripheral lymph nodes revealed a reduction of regulatory T cells, accompanied by increased T cell effector functions. Generalized activation of T cells was shown by elevated cytokine production upon stimulation. In addition, we observed no apparent shift towards T helper type 2 responses. It is likely, that the previously reported hypocorticism in this stress model led to a steady production of inflammatory Th1, Th2, and Th17 cytokines and obstructed the shift towards an anti-inflammatory response. In conclusion, we established chronic subordinate colony housing as a model to investigate the outcome of stress on the systemic immune status. We also provide evidence that distinct T helper cell subtypes react differentially to the suppressive effect of glucocorticoids.
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Affiliation(s)
- Dominic Schmidt
- Institute of Immunology, University of Regensburg, Franz-Joseph-Strauss-Allee 11, Regensburg, Germany
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Pelletier AM, Venkataramana S, Miller KG, Bennett BM, Nair DG, Lourenssen S, Blennerhassett MG. Neuronal nitric oxide inhibits intestinal smooth muscle growth. Am J Physiol Gastrointest Liver Physiol 2010; 298:G896-907. [PMID: 20338922 DOI: 10.1152/ajpgi.00259.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hyperplasia of smooth muscle contributes to the thickening of the intestinal wall that is characteristic of inflammation, but the mechanisms of growth control are unknown. Nitric oxide (NO) from enteric neurons expressing neuronal NO synthase (nNOS) might normally inhibit intestinal smooth muscle cell (ISMC) growth, and this was tested in vitro. In ISMC from the circular smooth muscle of the adult rat colon, chemical NO donors inhibited [(3)H]thymidine uptake in response to FCS, reducing this to baseline without toxicity. This effect was inhibited by the guanylyl cyclase inhibitor ODQ and potentiated by the phosphodiesterase-5 inhibitor zaprinast. Inhibition was mimicked by 8-bromo (8-Br)-cGMP, and ELISA measurements showed increased levels of cGMP but not cAMP in response to sodium nitroprusside. However, 8-Br-cAMP and cilostamide also showed inhibitory actions, suggesting an additional role for cAMP. Via a coculture model of ISMC and myenteric neurons, immunocytochemistry and image analysis showed that innervation reduced bromodeoxyuridine uptake by ISMC. Specific blockers of nNOS (7-NI, NAAN) significantly increased [(3)H]thymidine uptake in response to a standard stimulus, showing that nNOS activity normally inhibits ISMC growth. In vivo, nNOS axon number was reduced threefold by day 1 of trinitrobenzene sulfonic acid-induced rat colitis, preceding the hyperplasia of ISMC described earlier in this model. We conclude that NO can inhibit ISMC growth primarily via a cGMP-dependent mechanism. Functional evidence that NO derived from nNOS causes inhibition of ISMC growth in vitro predicts that the loss of nNOS expression in colitis contributes to ISMC hyperplasia in vivo.
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Affiliation(s)
- Anne-Marie Pelletier
- Gastrointestinal Diseases Research Unit, Queen's Univ., 76 Stuart St., Kingston, Ontario K7L 2V6
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