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Wang SR, Mallard CG, Cairns CA, Chung HK, Yoo D, Jaladanki SK, Xiao L, Wang JY. Stabilization of Cx43 mRNA via RNA-binding protein HuR regulated by polyamines enhances intestinal epithelial barrier function. Am J Physiol Gastrointest Liver Physiol 2023; 325:G518-G527. [PMID: 37788332 PMCID: PMC10894663 DOI: 10.1152/ajpgi.00143.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/22/2023] [Accepted: 09/29/2023] [Indexed: 10/05/2023]
Abstract
Gut barrier dysfunction occurs commonly in patients with critical disorders, leading to the translocation of luminal toxic substances and bacteria to the bloodstream. Connexin 43 (Cx43) acts as a gap junction protein and is crucial for intercellular communication and the diffusion of nutrients. The levels of cellular Cx43 are tightly regulated by multiple factors, including polyamines, but the exact mechanism underlying the control of Cx43 expression remains largely unknown. The RNA-binding protein HuR regulates the stability and translation of target mRNAs and is involved in many aspects of intestinal epithelial pathobiology. Here we show that HuR directly bound to Cx43 mRNA via its 3'-untranslated region in intestinal epithelial cells (IECs) and this interaction enhanced Cx43 expression by stabilizing Cx43 mRNA. Depletion of cellular polyamines inhibited the [HuR/Cx43 mRNA] complex and decreased the level of Cx43 protein by destabilizing its mRNA, but these changes were prevented by ectopic overexpression of HuR. Polyamine depletion caused intestinal epithelial barrier dysfunction, which was reversed by ectopic Cx43 overexpression. Moreover, overexpression of checkpoint kinase 2 in polyamine-deficient cells increased the [HuR/Cx43 mRNA] complex, elevated Cx43 levels, and promoted barrier function. These findings indicate that Cx43 mRNA is a novel target of HuR in IECs and that polyamines regulate Cx43 mRNA stability via HuR, thus playing a critical role in the maintenance of intestinal epithelial barrier function.NEW & NOTEWORTHY The current study shows that polyamines stabilize the Cx43 mRNA via HuR, thus enhancing the function of the Cx43-mediated gap junction. These findings suggest that induced Cx43 by HuR plays a critical role in the process by which polyamines regulate intestinal epithelial barrier.
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Affiliation(s)
- Shelley R Wang
- Cell Biology Group, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Caroline G Mallard
- Cell Biology Group, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Cassandra A Cairns
- Cell Biology Group, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Hee Kyoung Chung
- Cell Biology Group, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Dongyoon Yoo
- Cell Biology Group, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Suraj K Jaladanki
- Cell Biology Group, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Lan Xiao
- Cell Biology Group, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Jian-Ying Wang
- Cell Biology Group, Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, United States
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, United States
- Baltimore Veterans Affairs Medical Center, Baltimore, Maryland, United States
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Bhave S, Ho WLN, Cheng K, Omer M, Bousquet N, Guyer RA, Hotta R, Goldstein AM. Tamoxifen administration alters gastrointestinal motility in mice. Neurogastroenterol Motil 2022; 34:e14357. [PMID: 35279902 DOI: 10.1111/nmo.14357] [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] [Received: 05/05/2021] [Revised: 12/13/2021] [Accepted: 01/28/2022] [Indexed: 02/08/2023]
Abstract
BACKGROUND Tamoxifen is widely used for Cre-estrogen receptor-mediated genomic recombination in transgenic mouse models to mark cells for lineage tracing and to study gene function. However, recent studies have highlighted off-target effects of tamoxifen in various tissues and cell types when used for induction of Cre recombination. Despite the widespread use of these transgenic Cre models to assess gastrointestinal (GI) function, the effect of tamoxifen exposure on GI motility has not been described. METHODS We examined the effects of tamoxifen on GI motility by measuring total GI transit, gastric emptying, small intestinal transit, and colonic contractility in wild-type adult mice. KEY RESULTS We observed a significant delay in total GI transit in tamoxifen-treated mice, with unaltered gastric emptying, accelerated small intestinal transit, and abnormal colonic motility. CONCLUSION Our findings highlight the importance of considering GI motility alterations induced by tamoxifen when designing protocols that utilize tamoxifen as a Cre-driver for studying GI function.
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Affiliation(s)
- Sukhada Bhave
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Wing Lam N Ho
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Katarina Cheng
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Meredith Omer
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Nicole Bousquet
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Richard A Guyer
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Ryo Hotta
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Allan M Goldstein
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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3
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Ahmed MA, Venugopal S, Jung R. Engaging biological oscillators through second messenger pathways permits emergence of a robust gastric slow-wave during peristalsis. PLoS Comput Biol 2021; 17:e1009644. [PMID: 34871315 PMCID: PMC8675931 DOI: 10.1371/journal.pcbi.1009644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 12/16/2021] [Accepted: 11/15/2021] [Indexed: 11/19/2022] Open
Abstract
Peristalsis, the coordinated contraction—relaxation of the muscles of the stomach is important for normal gastric motility and is impaired in motility disorders. Coordinated electrical depolarizations that originate and propagate within a network of interconnected layers of interstitial cells of Cajal (ICC) and smooth muscle (SM) cells of the stomach wall as a slow-wave, underly peristalsis. Normally, the gastric slow-wave oscillates with a single period and uniform rostrocaudal lag, exhibiting network entrainment. Understanding of the integrative role of neurotransmission and intercellular coupling in the propagation of an entrained gastric slow-wave, important for understanding motility disorders, however, remains incomplete. Using a computational framework constituted of a novel gastric motility network (GMN) model we address the hypothesis that engaging biological oscillators (i.e., ICCs) by constitutive gap junction coupling mechanisms and enteric neural innervation activated signals can confer a robust entrained gastric slow-wave. We demonstrate that while a decreasing enteric neural innervation gradient that modulates the intracellular IP3 concentration in the ICCs can guide the aboral slow-wave propagation essential for peristalsis, engaging ICCs by recruiting the exchange of second messengers (inositol trisphosphate (IP3) and Ca2+) ensures a robust entrained longitudinal slow-wave, even in the presence of biological variability in electrical coupling strengths. Our GMN with the distinct intercellular coupling in conjunction with the intracellular feedback pathways and a rostrocaudal enteric neural innervation gradient allows gastric slow waves to oscillate with a moderate range of frequencies and to propagate with a broad range of velocities, thus preventing decoupling observed in motility disorders. Overall, the findings provide a mechanistic explanation for the emergence of decoupled slow waves associated with motility impairments of the stomach, offer directions for future experiments and theoretical work, and can potentially aid in the design of new interventional pharmacological and neuromodulation device treatments for addressing gastric motility disorders. The coordinated contraction and relaxation of the muscles of the stomach, known as peristalsis is important for normal gastric motility and primarily governed by electrical depolarizations that originate and propagate within a network of interconnected layers of interstitial cells of Cajal (ICCs) and smooth muscle cells of the stomach wall as a slow-wave. Under normal conditions, a gastric slow-wave oscillates with a single period and uniform rostrocaudal lag, exhibiting network entrainment. However, the understanding of intrinsic and extrinsic mechanisms that ensure propagation of a robust entrained slow-wave remains incomplete. Here, using a computational framework, we show that in conjunction with an enteric neural innervation gradient along the rostrocaudal ICC chain, and intercellular electrical coupling, the intercellular exchange of inositol trisphosphate between ICCs prevents decoupling by extending the longitudinal entrainment range along the stomach wall, even when variability in intercellular coupling exists. The findings from our study indicate ways that ensure the rostrocaudal spread of a robust gastric slow-wave and provide a mechanistic explanation for the emergence of decoupled slow waves associated with motility impairments of the stomach.
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Affiliation(s)
- Md Ashfaq Ahmed
- Department of Biomedical Engineering, Florida International University, Miami, Florida, United States of America
| | - Sharmila Venugopal
- Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail: (SV); (RJ)
| | - Ranu Jung
- Department of Biomedical Engineering, Florida International University, Miami, Florida, United States of America
- * E-mail: (SV); (RJ)
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Grubišić V, McClain JL, Fried DE, Grants I, Rajasekhar P, Csizmadia E, Ajijola OA, Watson RE, Poole DP, Robson SC, Christofi FL, Gulbransen BD. Enteric Glia Modulate Macrophage Phenotype and Visceral Sensitivity following Inflammation. Cell Rep 2020; 32:108100. [PMID: 32905782 PMCID: PMC7518300 DOI: 10.1016/j.celrep.2020.108100] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 07/02/2020] [Accepted: 08/11/2020] [Indexed: 12/20/2022] Open
Abstract
Mechanisms resulting in abdominal pain include altered neuro-immune interactions in the gastrointestinal tract, but the signaling processes that link immune activation with visceral hypersensitivity are unresolved. We hypothesized that enteric glia link the neural and immune systems of the gut and that communication between enteric glia and immune cells modulates the development of visceral hypersensitivity. To this end, we manipulated a major mechanism of glial intercellular communication that requires connexin-43 and assessed the effects on acute and chronic inflammation, visceral hypersensitivity, and immune responses. Deleting connexin-43 in glia protected against the development of visceral hypersensitivity following chronic colitis. Mechanistically, the protective effects of glial manipulation were mediated by disrupting the glial-mediated activation of macrophages through the macrophage colony-stimulating factor. Collectively, our data identified enteric glia as a critical link between gastrointestinal neural and immune systems that could be harnessed by therapies to ameliorate abdominal pain.
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Affiliation(s)
- Vladimir Grubišić
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI 48824, USA
| | - Jonathon L McClain
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI 48824, USA
| | - David E Fried
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI 48824, USA
| | - Iveta Grants
- Department of Anesthesiology, The Wexner Medical Center, The Ohio State University, 420 West 12th Avenue, Room 216, Columbus, OH 43210, USA
| | - Pradeep Rajasekhar
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science & Technology, Melbourne, VIC, Australia
| | - Eva Csizmadia
- Division of Gastroenterology, Department of Medicine and of Anesthesia, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Olujimi A Ajijola
- Cardiac Arrhythmia Center, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA, USA
| | - Ralph E Watson
- Department of Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - Daniel P Poole
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science & Technology, Melbourne, VIC, Australia
| | - Simon C Robson
- Division of Gastroenterology, Department of Medicine and of Anesthesia, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Fievos L Christofi
- Department of Anesthesiology, The Wexner Medical Center, The Ohio State University, 420 West 12th Avenue, Room 216, Columbus, OH 43210, USA
| | - Brian D Gulbransen
- Department of Physiology and Neuroscience Program, Michigan State University, 567 Wilson Road, East Lansing, MI 48824, USA.
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Wong J, Chopra J, Chiang LLW, Liu T, Ho J, Wu WKK, Tse G, Wong SH. The Role of Connexins in Gastrointestinal Diseases. J Mol Biol 2019; 431:643-652. [PMID: 30639409 DOI: 10.1016/j.jmb.2019.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/03/2018] [Accepted: 01/04/2019] [Indexed: 12/13/2022]
Abstract
Gap junctions are hexagonal arrays of protein molecules in the plasma membrane and were first described in Mauthner cell synapses of goldfish. They form pathways for coupling between cells, allowing passive, electrotonic spread of ions and also passage of larger molecules such as amino acids and nucleotides. They are expressed in both excitable and non-excitable tissues. Each gap junction is made of two connexons, which are hexameric proteins of the connexin subunit. In this review, the roles that connexins play in gastrointestinal motility, the mechanisms of altered connexin expression leading to inflammatory bowel disease, gastrointestinal infections, and gastrointestinal symptoms in autistic spectrum disorder are discussed in detail.
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Affiliation(s)
- Jeremy Wong
- Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, PR China
| | - Jasmine Chopra
- Faculty of Arts and Science, University of Toronto, Toronto, Canada
| | | | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China
| | - Jeffery Ho
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, PR China; Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, PR China
| | - William K K Wu
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, PR China; Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, PR China
| | - Gary Tse
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, PR China; Li Ka Shing Institute of Health Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, PR China.
| | - Sunny Hei Wong
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, PR China; Li Ka Shing Institute of Health Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, PR China.
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6
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Langhorst H, Jüttner R, Groneberg D, Mohtashamdolatshahi A, Pelz L, Purfürst B, Schmidt-Ott KM, Friebe A, Rathjen FG. The IgCAM CLMP regulates expression of Connexin43 and Connexin45 in intestinal and ureteral smooth muscle contraction in mice. Dis Model Mech 2018; 11:dmm.032128. [PMID: 29361518 PMCID: PMC5894946 DOI: 10.1242/dmm.032128] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/09/2018] [Indexed: 11/25/2022] Open
Abstract
CAR-like membrane protein (CLMP), an immunoglobulin cell adhesion molecule (IgCAM), has been implicated in congenital short-bowel syndrome in humans, a condition with high mortality for which there is currently no cure. We therefore studied the function of CLMP in a Clmp-deficient mouse model. Although we found that the levels of mRNAs encoding Connexin43 or Connexin45 were not or were only marginally affected, respectively, by Clmp deficiency, the absence of CLMP caused a severe reduction of both proteins in smooth muscle cells of the intestine and of Connexin43 in the ureter. Analysis of calcium signaling revealed a disordered cell-cell communication between smooth muscle cells, which in turn induced an impaired and uncoordinated motility of the intestine and the ureter. Consequently, insufficient transport of chyme and urine caused a fatal delay to thrive, a high rate of mortality, and provoked a severe hydronephrosis in CLMP knockouts. Neurotransmission and the capability of smooth muscle cells to contract in ring preparations of the intestine were not altered. Physical obstructions were not detectable and an overall normal histology in the intestine as well as in the ureter was observed, except for a slight hypertrophy of smooth muscle layers. Deletion of Clmp did not lead to a reduced length of the intestine as shown for the human CLMP gene but resulted in gut malrotations. In sum, the absence of CLMP caused functional obstructions in the intestinal tract and ureter by impaired peristaltic contractions most likely due to a lack of gap-junctional communication between smooth muscle cells. Summary: The function of the immunoglobulin cell adhesion molecule CLMP was investigated in a mouse model. CLMP is essential for intestinal and ureteral peristalsis, and for expression of Connexin43 and 45 in smooth muscle cells.
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Affiliation(s)
- Hanna Langhorst
- Max-Delbrück-Center for Molecular Medicine, DE-13092 Berlin, Germany
| | - René Jüttner
- Max-Delbrück-Center for Molecular Medicine, DE-13092 Berlin, Germany
| | - Dieter Groneberg
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, DE-97070 Würzburg, Germany
| | | | - Laura Pelz
- Max-Delbrück-Center for Molecular Medicine, DE-13092 Berlin, Germany
| | - Bettina Purfürst
- Max-Delbrück-Center for Molecular Medicine, DE-13092 Berlin, Germany
| | - Kai M Schmidt-Ott
- Charité-Universitätsmedizin Berlin, Department of Nephrology, Charitéplatz 1, DE-10117 Berlin, Germany
| | - Andreas Friebe
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, DE-97070 Würzburg, Germany
| | - Fritz G Rathjen
- Max-Delbrück-Center for Molecular Medicine, DE-13092 Berlin, Germany
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Diezmos EF, Bertrand PP, Liu L. Purinergic Signaling in Gut Inflammation: The Role of Connexins and Pannexins. Front Neurosci 2016; 10:311. [PMID: 27445679 PMCID: PMC4925662 DOI: 10.3389/fnins.2016.00311] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/20/2016] [Indexed: 12/13/2022] Open
Abstract
Purinergic receptors play an important role in inflammation, and can be activated by ATP released via pannexin channels and/or connexin hemichannels. The purinergic P2X7 receptor (P2X7R) is of interest since it is involved in apoptosis when activated. Most studies focus on the influence of pannexin-1 (Panx1) and connexin 43 (Cx43) on ATP release and how it affects P2X7R function during inflammation. Inflammatory bowel disease (IBD) is characterized by uncontrolled inflammation within the gastrointestinal system. At present, the pathophysiology of this disease remains largely unknown but it may involve the interplay between P2X7R, Panx1, and Cx43. There are two main types of IBD, ulcerative colitis and Crohn's disease, that are classified by their location and frequency of inflammation. Current research suggests that alterations to normal functioning of innate and adaptive immunity may be a factor in disease progression. The involvement of purinergic receptors, connexins, and pannexins in IBD is a relatively novel notion in the context of gastrointestinal inflammation, and has been explored by various research groups. Thus, the present review focuses on the current research involving connexins, pannexins, and purinergic receptors within the gut and enteric nervous system, and will examine their involvement in inflammation and the pathophysiology of IBD.
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Affiliation(s)
- Erica F Diezmos
- School of Medical Sciences, University of New South Wales Sydney, NSW, Australia
| | - Paul P Bertrand
- School of Medical Sciences, University of New South WalesSydney, NSW, Australia; School of Medical Sciences, RMIT UniversityBundoora, VIC, Australia
| | - Lu Liu
- School of Medical Sciences, University of New South Wales Sydney, NSW, Australia
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8
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Maes M, Cogliati B, Crespo Yanguas S, Willebrords J, Vinken M. Roles of connexins and pannexins in digestive homeostasis. Cell Mol Life Sci 2015; 72:2809-21. [PMID: 26084872 DOI: 10.1007/s00018-015-1961-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 06/11/2015] [Indexed: 12/21/2022]
Abstract
Connexin proteins are abundantly present in the digestive system. They primarily form gap junctions, which control the intercellular exchange of critical homeostasis regulators. By doing so, gap junctions drive a plethora of gastrointestinal and hepatic functional features, including gastric and gut motility, gastric acid secretion, intestinal innate immune defense, xenobiotic biotransformation, glycogenolysis, bile secretion, ammonia detoxification and plasma protein synthesis. In the last decade, it has become clear that connexin hemichannels, which are the structural precursors of gap junctions, also provide a pathway for cellular communication, namely between the cytosol and the extracellular environment. Although merely pathological functions have been described, some physiological roles have been attributed to connexin hemichannels, in particular in the modulation of colonic motility. This equally holds true for cellular channels composed of pannexins, connexin-like proteins recently identified in the intestine and the liver, which have become acknowledged key players in inflammatory processes and that have been proposed to control colonic motility, secretion and blood flow.
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Affiliation(s)
- Michaël Maes
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
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9
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Nagy JI, Urena-Ramirez V, Ghia JE. Functional alterations in gut contractility after connexin36 ablation and evidence for gap junctions forming electrical synapses between nitrergic enteric neurons. FEBS Lett 2014; 588:1480-90. [PMID: 24548563 PMCID: PMC4043341 DOI: 10.1016/j.febslet.2014.02.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 02/05/2014] [Accepted: 02/06/2014] [Indexed: 02/02/2023]
Abstract
Neurons in the enteric nervous system utilize numerous neurotransmitters to orchestrate rhythmic gut smooth muscle contractions. We examined whether electrical synapses formed by gap junctions containing connexin36 also contribute to communication between enteric neurons in mouse colon. Spontaneous contractility properties and responses to electrical field stimulation and cholinergic agonist were altered in gut from connexin36 knockout vs. wild-type mice. Immunofluorescence revealed punctate labelling of connexin36 that was localized at appositions between somata of enteric neurons immunopositive for the enzyme nitric oxide synthase. There is indication for a possible functional role of gap junctions between inhibitory nitrergic enteric neurons.
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Affiliation(s)
- James Imre Nagy
- Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
| | - Viridiana Urena-Ramirez
- Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada; Department of Immunology and Internal Medicine section of Gastroenterology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
| | - Jean-Eric Ghia
- Department of Immunology and Internal Medicine section of Gastroenterology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
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10
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McClain J, Grubišić V, Fried D, Gomez-Suarez RA, Leinninger GM, Sévigny J, Parpura V, Gulbransen BD. Ca2+ responses in enteric glia are mediated by connexin-43 hemichannels and modulate colonic transit in mice. Gastroenterology 2014; 146:497-507.e1. [PMID: 24211490 PMCID: PMC3935238 DOI: 10.1053/j.gastro.2013.10.061] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 10/18/2013] [Accepted: 10/30/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS In the enteric nervous system, neurotransmitters initiate changes in calcium (Ca(2+) responses) in glia, but it is not clear how this process affects intestinal function. We investigated whether Ca(2+)-mediated responses in enteric glia are required to maintain gastrointestinal function. METHODS We used in situ Ca(2+) imaging to monitor glial Ca(2+) responses, which were manipulated with pharmacologic agents or via glia-specific disruption of the gene encoding connexin-43 (Cx43) (hGFAP::CreER(T2+/-)/Cx43(f/f) mice). Gastrointestinal function was assessed based on pellet output, total gut transit, colonic bead expulsion, and muscle tension recordings. Proteins were localized and quantified by immunohistochemistry, immunoblot, and reverse transcription polymerase chain reaction analyses. RESULTS Ca(2+) responses in enteric glia of mice were mediated by Cx43 hemichannels. Cx43 immunoreactivity was confined to enteric glia within the myenteric plexus of the mouse colon; the Cx43 inhibitors carbenoxolone and 43Gap26 inhibited the ability of enteric glia to propagate Ca(2+) responses. In vivo attenuation of Ca(2+) responses in the enteric glial network slowed gut transit overall and delayed colonic transit--these changes are also observed during normal aging. Altered motility with increasing age was associated with reduced glial Ca(2+)-mediated responses and changes in glial expression of Cx43 messenger RNA and protein. CONCLUSIONS Ca(2+)-mediated responses in enteric glia regulate gastrointestinal function in mice. Altered intercellular signaling between enteric glia and neurons might contribute to motility disorders.
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Affiliation(s)
- Jonathon McClain
- Neuroscience Program and Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA
| | - Vladimir Grubišić
- Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy and Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL 35294, USA
| | - David Fried
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824
| | - Roberto A Gomez-Suarez
- Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy and Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL 35294, USA.,Department of Pediatrics Division of Pediatric Gastroenterology Hepatology And Nutrition at Nemours Chlidren's Hospital. Orlando, FL 32827, USA
| | - Gina M Leinninger
- Neuroscience Program and Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA
| | - Jean Sévigny
- Département de microbiologie-infectiologie et d'immunologie, Faculté de Médecine, Université Laval, Québec, QC, Canada.,Centre de recherche du CHU de Québec, Québec, QC, G1V 4G2 Canada
| | - Vladimir Parpura
- Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy and Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL 35294, USA.,Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
| | - Brian D Gulbransen
- Neuroscience Program and Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA
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11
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Sancho M, Triguero D, Garcia-Pascual A. Direct coupling through gap junctions is not involved in urethral neurotransmission. Am J Physiol Renal Physiol 2011; 300:F864-72. [DOI: 10.1152/ajprenal.00641.2010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Interstitial cells of Cajal (ICC) are believed to participate in urethral neurotransmission and it was proposed that direct coupling of ICC and smooth muscle cells (SMC) through gap junctions (GJ) is involved, although this still remains unclear. Hence, we investigated the distribution of different connexins (Cx 43, Cx40, and Cx37) in the sheep and rat urethra, as well as their possible role in neurotransmission. Conventional PCR confirmed that three Cxs are expressed in the urethra. Moreover, both Cx43 and Cx37-immunoreactivity (-ir) were present in SMC, ICC, and the urothelium, although Cx37-ir was significantly weaker and Cx40-ir was limited to the endothelium. While these results indicate that GJ intercellular communication could occur between SMC and ICC, neither the contractile (noradrenergic) nor the relaxant (nitrergic) responses of the rat and sheep urethra to electrical field stimulation were significantly modified by two different GJ inhibitors: 18α-glycyrrhetinic acid and a cocktail of Cx mimetic peptides (Cx43Gap 26,Cx37, Cx43Gap 27, andCx40Gap 27). By contrast, contractions induced by high K+were effectively reduced by both blockers, evidence that they effectively inhibit intercellular communication. These results indicate that GJ are not implicated in urethral neurotransmission, although the question of whether ICC modulate neurotransmission through some other mechanism remains to be determined.
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Affiliation(s)
- Maria Sancho
- Department of Physiology, Veterinary Faculty, Complutense University, Madrid, Spain
| | - Domingo Triguero
- Department of Physiology, Veterinary Faculty, Complutense University, Madrid, Spain
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Yoon MS, Bechmann L, Obermann M, Yepnjouo O, Egensperger R, Gerken G, Katsarava Z, Thomale J, Holtmann G. Recombinant human erythropoietin counteracts cisplatin-induced visceral hyperalgesia. Neurosci Bull 2010; 26:282-8. [PMID: 20657614 DOI: 10.1007/s12264-010-0413-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE Cisplatin exerts its cytotoxic effect through distinct DNA lesions, leading to peripheral neuropathy. The risk of sensory neuropathy is a common problem during cancer treatment with cisplatin, leading to somatic hyperalgesia. Yet, data focussing on cisplatin-induced impairment of the autonomic nervous system are limited. The present study was aimed to investigate the effect of recombinant human erythropoietin (rhEPO) on cisplatin-induced visceral hyperalgesia. METHODS C57BL/6 mice were treated either with cisplatin (2 mg/kg, once per week) or with cisplatin (2 mg/kg, once per week) plus rhEPO (40 microg/kg, 3 times per week) for 8 weeks. Controls were treated with saline. To quantify the visceromotor response (VMR) at week 9, standardized electrodes were implanted into the external oblique musculature for electromyographic recordings. After that, animals were decapitated and dorsal root ganglia (DRG) was removed for transmission electron microscopy studies. RESULTS Cisplatin-treated mice showed a significant increase of VMR compared to the controls [(7080 +/- 969) vs (2864 +/- 279); P< 0.001], while rhEPO dramatically counteracted this effect [(2962 +/- 336) vs (7080 +/- 969); P< 0.001)]. Transmission electron microscopy revealed cisplatin-induced structural lesions of nuclear membrane in DRG cells, which could be ameliorated by rhEPO. CONCLUSION Erythropoietin can significantly ameliorate the cisplatin-induced visceral hyperplasia and DRG nuclear membrane structure damage in mice, indicating a neuroprotective role of erythropoietin.
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Affiliation(s)
- Min-Suk Yoon
- Department of Neurology, University of Duisburg-Essen, Essen, Germany.
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Sina C, Gavrilova O, Förster M, Till A, Derer S, Hildebrand F, Raabe B, Chalaris A, Scheller J, Rehmann A, Franke A, Ott S, Häsler R, Nikolaus S, Fölsch UR, Rose-John S, Jiang HP, Li J, Schreiber S, Rosenstiel P. G protein-coupled receptor 43 is essential for neutrophil recruitment during intestinal inflammation. THE JOURNAL OF IMMUNOLOGY 2009; 183:7514-22. [PMID: 19917676 DOI: 10.4049/jimmunol.0900063] [Citation(s) in RCA: 271] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Molecular danger signals attract neutrophilic granulocytes (polymorphonuclear leukocytes (PMNs)) to sites of infection. The G protein-coupled receptor (GPR) 43 recognizes propionate and butyrate and is abundantly expressed on PMNs. The functional role of GPR43 activation for in vivo orchestration of immune response is unclear. We examined dextrane sodium sulfate (DSS)-induced acute and chronic intestinal inflammatory response in wild-type and Gpr43-deficient mice. The severity of colonic inflammation was assessed by clinical signs, histological scoring, and cytokine production. Chemotaxis of wild-type and Gpr43-deficient PMNs was assessed through transwell cell chemotactic assay. A reduced invasion of PMNs and increased mortality due to septic complications were observed in acute DSS colitis. In chronic DSS colitis, Gpr43(-/-) animals showed diminished PMN intestinal migration, but protection against inflammatory tissue destruction. No significant difference in PMN migration and cytokine secretion was detected in a sterile inflammatory model. Ex vivo experiments show that GPR43-induced migration is dependent on activation of the protein kinase p38alpha, and that this signal acts in cooperation with the chemotactic cytokine keratinocyte chemoattractant. Interestingly, shedding of L-selectin in response to propionate and butyrate was compromised in Gpr43(-/-) mice. These results indicate a critical role for GPR43-mediated recruitment of PMNs in containing intestinal bacterial translocation, yet also emphasize the bipotential role of PMNs in mediating tissue destruction in chronic intestinal inflammation.
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Affiliation(s)
- Christian Sina
- Institute of Clinical Molecular Biology, University Hospital Schleswig-Holstein, Kiel, Germany
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von Maltzahn J, Kreuzberg MM, Matern G, Euwens C, Höher T, Wörsdörfer P, Willecke K. C-terminal tagging with eGFP yields new insights into expression of connexin45 but prevents rescue of embryonic lethal connexin45-deficient mice. Eur J Cell Biol 2009; 88:481-94. [DOI: 10.1016/j.ejcb.2009.04.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 04/09/2009] [Accepted: 04/20/2009] [Indexed: 10/20/2022] Open
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Brierley SM, Page AJ, Hughes PA, Adam B, Liebregts T, Cooper NJ, Holtmann G, Liedtke W, Blackshaw LA. Selective role for TRPV4 ion channels in visceral sensory pathways. Gastroenterology 2008; 134:2059-69. [PMID: 18343379 PMCID: PMC2504007 DOI: 10.1053/j.gastro.2008.01.074] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2007] [Accepted: 01/18/2008] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS Although there are many candidates as molecular mechanotransducers, so far there has been no evidence for molecular specialization of visceral afferents. Here, we show that colonic afferents express a specific molecular transducer that underlies their specialized mechanosensory function: the transient receptor potential channel, vanilloid 4 (TRPV4). METHODS We found TRPV4 mRNA is highly enriched in colonic sensory neurons compared with other visceral and somatic sensory neurons. TRPV4 protein was found in colonic nerve fibers from patients with inflammatory bowel disease, and it colocalized in a subset of fibers with the sensory neuropeptide CGRP in mice. We characterized the responses of 8 subtypes of vagal, splanchnic, and pelvic mechanoreceptors. RESULTS Mechanosensory responses of colonic serosal and mesenteric afferents were enhanced by a TRPV4 agonist and dramatically reduced by targeted deletion of TRPV4 or by a TRP antagonist. Other subtypes of vagal and pelvic afferents, by contrast, were unaffected by these interventions. The behavioral responses to noxious colonic distention were also substantially reduced in mice lacking TRPV4. CONCLUSIONS These data indicate that TRPV4 contributes to mechanically evoked visceral pain, with relevance to human disease. In view of its distribution in favor of specific populations of visceral afferents, we propose that TRPV4 may present a selective novel target for the reduction of visceral pain, which is an important opportunity in the absence of current treatments.
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Affiliation(s)
- Stuart M Brierley
- Discipline of Physiology, School of Molecular and Biomedical Sciences, The University of Adelaide, Nerve-Gut Research Laboratory, Department of Gastroenterology & Hepatology, Hanson Institute, Royal Adelaide Hospital, Adelaide, AUSTRALIA
| | - Amanda J Page
- Discipline of Physiology, School of Molecular and Biomedical Sciences, The University of Adelaide, Discipline of Medicine, The University of Adelaide, Nerve-Gut Research Laboratory, Department of Gastroenterology & Hepatology, Hanson Institute, Royal Adelaide Hospital, Adelaide, AUSTRALIA
| | - Patrick A Hughes
- Discipline of Physiology, School of Molecular and Biomedical Sciences, The University of Adelaide, Nerve-Gut Research Laboratory, Department of Gastroenterology & Hepatology, Hanson Institute, Royal Adelaide Hospital, Adelaide, AUSTRALIA
| | - Birgit Adam
- Nerve-Gut Research Laboratory, Department of Gastroenterology & Hepatology, Hanson Institute, Royal Adelaide Hospital, Adelaide, AUSTRALIA
| | - Tobias Liebregts
- Nerve-Gut Research Laboratory, Department of Gastroenterology & Hepatology, Hanson Institute, Royal Adelaide Hospital, Adelaide, AUSTRALIA
| | - Nicole J Cooper
- Nerve-Gut Research Laboratory, Department of Gastroenterology & Hepatology, Hanson Institute, Royal Adelaide Hospital, Adelaide, AUSTRALIA
| | - Gerald Holtmann
- Discipline of Medicine, The University of Adelaide, Nerve-Gut Research Laboratory, Department of Gastroenterology & Hepatology, Hanson Institute, Royal Adelaide Hospital, Adelaide, AUSTRALIA
| | - Wolfgang Liedtke
- Center for Translational Neuroscience, Duke University, Durham, North Carolina 27710, USA
| | - L Ashley Blackshaw
- Discipline of Physiology, School of Molecular and Biomedical Sciences, The University of Adelaide, Discipline of Medicine, The University of Adelaide, Nerve-Gut Research Laboratory, Department of Gastroenterology & Hepatology, Hanson Institute, Royal Adelaide Hospital, Adelaide, AUSTRALIA
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