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Stavely R, Ott LC, Rashidi N, Sakkal S, Nurgali K. The Oxidative Stress and Nervous Distress Connection in Gastrointestinal Disorders. Biomolecules 2023; 13:1586. [PMID: 38002268 PMCID: PMC10669114 DOI: 10.3390/biom13111586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/19/2023] [Accepted: 10/23/2023] [Indexed: 11/26/2023] Open
Abstract
Oxidative stress is increasingly recognized as a central player in a range of gastrointestinal (GI) disorders, as well as complications stemming from therapeutic interventions. This article presents an overview of the mechanisms of oxidative stress in GI conditions and highlights a link between oxidative insult and disruption to the enteric nervous system (ENS), which controls GI functions. The dysfunction of the ENS is characteristic of a spectrum of disorders, including neurointestinal diseases and conditions such as inflammatory bowel disease (IBD), diabetic gastroparesis, and chemotherapy-induced GI side effects. Neurons in the ENS, while essential for normal gut function, appear particularly vulnerable to oxidative damage. Mechanistically, oxidative stress in enteric neurons can result from intrinsic nitrosative injury, mitochondrial dysfunction, or inflammation-related pathways. Although antioxidant-based therapies have shown limited efficacy, recognizing the multifaceted role of oxidative stress in GI diseases offers a promising avenue for future interventions. This comprehensive review summarizes the literature to date implicating oxidative stress as a critical player in the pathophysiology of GI disorders, with a focus on its role in ENS injury and dysfunction, and highlights opportunities for the development of targeted therapeutics for these diseases.
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Affiliation(s)
- Rhian Stavely
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Leah C. Ott
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Niloufar Rashidi
- Institute for Health and Sport, Victoria University, St Albans, VIC 3021, Australia
| | - Samy Sakkal
- Institute for Health and Sport, Victoria University, St Albans, VIC 3021, Australia
| | - Kulmira Nurgali
- Institute for Health and Sport, Victoria University, St Albans, VIC 3021, Australia
- Department of Medicine Western Health, The University of Melbourne, St Albans, VIC 3021, Australia
- Regenerative Medicine and Stem Cell Program, Australian Institute for Musculoskeletal Science (AIMSS), St Albans, VIC 3021, Australia
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Claudino Dos Santos JC, Lima MPP, Brito GADC, Viana GSDB. Role of enteric glia and microbiota-gut-brain axis in parkinson disease pathogenesis. Ageing Res Rev 2023; 84:101812. [PMID: 36455790 DOI: 10.1016/j.arr.2022.101812] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 11/30/2022]
Abstract
The microbiota-gut-brain axis or simple gut-brain axis (GBA) is a complex and interactive bidirectional communication network linking the gut to the brain. Alterations in the composition of the gut microbiome have been linked to GBA dysfunction, central nervous system (CNS) inflammation, and dopaminergic degeneration, as those occurring in Parkinson's disease (PD). Besides inflammation, the activation of brain microglia is known to play a central role in the damage of dopaminergic neurons. Inflammation is attributed to the toxic effect of aggregated α-synuclein, in the brain of PD patients. It has been suggested that the α-synuclein misfolding might begin in the gut and spread "prion-like", via the vagus nerve into the lower brainstem and ultimately to the midbrain, known as the Braak hypothesis. In this review, we discuss how the microbiota-gut-brain axis and environmental influences interact with the immune system to promote a pro-inflammatory state that is involved in the initiation and progression of misfolded α-synuclein proteins and the beginning of the early non-motor symptoms of PD. Furthermore, we describe a speculative bidirectional model that explains how the enteric glia is involved in the initiation and spreading of inflammation, epithelial barrier disruption, and α-synuclein misfolding, finally reaching the central nervous system and contributing to neuroinflammatory processes involved with the initial non-motor symptoms of PD.
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Affiliation(s)
- Júlio César Claudino Dos Santos
- Medical School of the Christus University Center - UNICHRISTUS, Fortaleza, CE, Brazil; Graduate Program in Morphofunctional Sciences, Federal University of Ceará - UFC, Fortaleza, CE, Brazil.
| | | | - Gerly Anne de Castro Brito
- Physiology and Pharmacology Department of the Federal University of Ceará - UFC, Fortaleza, CE, Brazil; Morphology Department of the Federal University of Ceará - UFC, Fortaleza, CE, Brazil
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Stavely R, Sahakian L, Filippone RT, Stojanovska V, Bornstein JC, Sakkal S, Nurgali K. Oxidative Stress-Induced HMGB1 Translocation in Myenteric Neurons Contributes to Neuropathy in Colitis. Biomolecules 2022; 12:biom12121831. [PMID: 36551259 PMCID: PMC9776169 DOI: 10.3390/biom12121831] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 11/29/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022] Open
Abstract
High-mobility group box 1 (HMGB1) is a damage-associated molecular pattern released by dying cells to stimulate the immune response. During cell death, HMGB1 is translocated from the nucleus to the cytoplasm and passively released. High levels of secreted HMGB1 are observed in the faeces of inflammatory bowel disease (IBD) patients, indicating its role in IBD pathophysiology and potential as a non-invasive IBD biomarker. HMGB1 is important in regulating neuronal damage in the central nervous system; its pathological activity is intertwined with oxidative stress and inflammation. In this study, HMGB1 expression in the enteric nervous system and its relevance to intestinal neuroinflammation is explored in organotypic cultures of the myenteric plexus exposed to oxidative stimuli and in Winnie mice with spontaneous chronic colitis. Oxidative stimuli induced cytoplasmic translocation of HMGB1 in myenteric neurons in organotypic preparations. HMGB1 translocation correlated with enteric neuronal loss and oxidative stress in the myenteric ganglia of Winnie mice. Inhibition of HMGB1 by glycyrrhizic acid ameliorated HMGB1 translocation and myenteric neuronal loss in Winnie mice. These data highlight modulation of HMGB1 signalling as a therapeutic strategy to reduce the consequences of enteric neuroinflammation in colitis, warranting the exploration of therapeutics acting on the HMGB1 pathway as an adjunct treatment with current anti-inflammatory agents.
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Affiliation(s)
- Rhian Stavely
- Institute for Health and Sport, Victoria University, Western Centre for Health, Research and Education, Sunshine Hospital, St Albans, VIC 3021, Australia
- Department of Pediatric Surgery, Pediatric Surgery Research Laboratories, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
- Department of Medicine Western Health, The University of Melbourne, St Albans, VIC 3021, Australia
| | - Lauren Sahakian
- Institute for Health and Sport, Victoria University, Western Centre for Health, Research and Education, Sunshine Hospital, St Albans, VIC 3021, Australia
| | - Rhiannon T. Filippone
- Institute for Health and Sport, Victoria University, Western Centre for Health, Research and Education, Sunshine Hospital, St Albans, VIC 3021, Australia
| | - Vanesa Stojanovska
- Institute for Health and Sport, Victoria University, Western Centre for Health, Research and Education, Sunshine Hospital, St Albans, VIC 3021, Australia
- The Ritchie Centre, Hudson Institute of Medical Research, Monash Health Translation Precinct, Melbourne, VIC 3168, Australia
| | - Joel C. Bornstein
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Samy Sakkal
- Institute for Health and Sport, Victoria University, Western Centre for Health, Research and Education, Sunshine Hospital, St Albans, VIC 3021, Australia
| | - Kulmira Nurgali
- Institute for Health and Sport, Victoria University, Western Centre for Health, Research and Education, Sunshine Hospital, St Albans, VIC 3021, Australia
- Department of Medicine Western Health, The University of Melbourne, St Albans, VIC 3021, Australia
- Regenerative Medicine and Stem Cell Program, Australian Institute for Musculoskeletal Science (AIMSS), St Albans, VIC 3021, Australia
- Correspondence:
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Ahmadzai MM, McClain JL, Dharshika C, Seguella L, Giancola F, De Giorgio R, Gulbransen BD. LPAR1 regulates enteric nervous system function through glial signaling and contributes to chronic intestinal pseudo-obstruction. J Clin Invest 2022; 132:149464. [PMID: 35166239 PMCID: PMC8843750 DOI: 10.1172/jci149464] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 12/21/2021] [Indexed: 12/30/2022] Open
Abstract
Gastrointestinal motility disorders involve alterations to the structure and/or function of the enteric nervous system (ENS) but the causal mechanisms remain unresolved in most cases. Homeostasis and disease in the ENS are processes that are regulated by enteric glia. Signaling mediated through type I lysophosphatidic acid receptors (LPAR1) has recently emerged as an important mechanism that contributes to disease, in part, through effects on peripheral glial survival and function. Enteric glia express LPAR1 but its role in ENS function and motility disorders is unknown. We used a combination of genetic, immunohistochemical, calcium imaging, and in vivo pharmacological approaches to investigate the role of LPAR1 in enteric glia. LPAR1 was enriched in enteric glia in mice and humans and LPA stimulated intracellular calcium responses in enteric glia, subsequently recruiting activity in a subpopulation of myenteric neurons. Blocking LPAR1 in vivo with AM966 attenuated gastrointestinal motility in mice and produced marked enteric neuro- and gliopathy. Samples from humans with chronic intestinal pseudo-obstruction (CIPO), a severe motility disorder, showed reduced glial LPAR1 expression in the colon and ileum. These data suggest that enteric glial LPAR1 signaling regulates gastrointestinal motility through enteric glia and could contribute to severe motility disorders in humans such as CIPO.
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Affiliation(s)
- Mohammad M Ahmadzai
- Department of Physiology, Neuroscience Program.,College of Osteopathic Medicine, and
| | | | - Christine Dharshika
- Department of Physiology, Neuroscience Program.,College of Human Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Luisa Seguella
- Department of Physiology, Neuroscience Program.,Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, Rome, Italy
| | - Fiorella Giancola
- Department of Translational Medicine, University of Ferrara, Ferrara, Italy.,St. Orsola-Malpighi Hospital, Bologna, Italy
| | - Roberto De Giorgio
- Department of Translational Medicine, University of Ferrara, Ferrara, Italy
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Seguella L, Gulbransen BD. Enteric glial biology, intercellular signalling and roles in gastrointestinal disease. Nat Rev Gastroenterol Hepatol 2021; 18:571-587. [PMID: 33731961 PMCID: PMC8324524 DOI: 10.1038/s41575-021-00423-7] [Citation(s) in RCA: 143] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/28/2021] [Indexed: 02/07/2023]
Abstract
One of the most transformative developments in neurogastroenterology is the realization that many functions normally attributed to enteric neurons involve interactions with enteric glial cells: a large population of peripheral neuroglia associated with enteric neurons throughout the gastrointestinal tract. The notion that glial cells function solely as passive support cells has been refuted by compelling evidence that demonstrates that enteric glia are important homeostatic cells of the intestine. Active signalling mechanisms between enteric glia and neurons modulate gastrointestinal reflexes and, in certain circumstances, function to drive neuroinflammatory processes that lead to long-term dysfunction. Bidirectional communication between enteric glia and immune cells contributes to gastrointestinal immune homeostasis, and crosstalk between enteric glia and cancer stem cells regulates tumorigenesis. These neuromodulatory and immunomodulatory roles place enteric glia in a unique position to regulate diverse gastrointestinal disease processes. In this Review, we discuss current concepts regarding enteric glial development, heterogeneity and functional roles in gastrointestinal pathophysiology and pathophysiology, with a focus on interactions with neurons and immune cells. We also present a working model to differentiate glial states based on normal function and disease-induced dysfunctions.
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Affiliation(s)
- Luisa Seguella
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, Rome, Italy
- Department of Physiology, Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - Brian D Gulbransen
- Department of Physiology, Neuroscience Program, Michigan State University, East Lansing, MI, USA.
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Etiology of Colitis-Complex Diarrhea in Growing Pigs: A Review. Animals (Basel) 2021; 11:ani11072151. [PMID: 34359279 PMCID: PMC8300613 DOI: 10.3390/ani11072151] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Diarrhea in growing pigs is a challenge for the pig industry since it is associated with reduced animal welfare, retarded growth, increased feed conversion ratio, and is often treated with antibiotics. One of the major causes of diarrhea in the growing period is large intestinal inflammation, often referred to as colitis. The exact causes of colitis-complex diarrhea are still to be understood, but dietary factors and/or pathogens have been recognized as the major factors in developing colitis-complex diarrhea. In this review, a thorough picture of pathogens, dietary factors, and a number of possible biomarkers related to colitis-complex diarrhea is presented. Abstract Colitis-complex diarrhea (CCD) in pigs can be defined as a type of diarrhea, which is associated with colonic inflammation and disrupted colonic gut barrier functionality in growing pigs (4–16 weeks post-weaning). It is a challenge for the pig industry as it is associated with the high use of antibiotics, reduced animal welfare, and depressed growth rate. The exact etiology of CCD is still unclear; however, pathogens including Brachyspira (B.) hyodysenteriae, B. pilosicoli, and swine whipworms such as Trichuris (T.) suis have been involved in specific colitis (SC). In the absence of specific pathogens, dietary factors, such as high levels of protein, pelleted feedstuffs, and lack of sufficient antioxidants, can result in non-specific colitis (NSC). On the other hand, supplement of polyunsaturated fatty acids (PUFA) and polyphenols, sufficient supply of essential amino acids (e.g., threonine, cysteine, and proline), short-chain fatty acids (SCFA; especially butyrate), and resistant starch have shown to confer preventing/ameliorating effects on CCD. Different putative biomarkers associated with CCD have been presented. It is anticipated that a comprehensive picture of the possible causes of CCD and potential dietary interventions could cast light on the direction of future studies aimed at developing preventive and curative strategies against CCD in growing pigs.
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Sanders KM, Mutafova-Yambolieva VN. Neurotransmitters responsible for purinergic motor neurotransmission and regulation of GI motility. Auton Neurosci 2021; 234:102829. [PMID: 34146957 DOI: 10.1016/j.autneu.2021.102829] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/25/2021] [Accepted: 05/28/2021] [Indexed: 12/17/2022]
Abstract
Classical concepts of peripheral neurotransmission were insufficient to explain enteric inhibitory neurotransmission. Geoffrey Burnstock and colleagues developed the idea that ATP or a related purine satisfies the criteria for a neurotransmitter and serves as an enteric inhibitory neurotransmitter in GI muscles. Cloning of purinergic receptors and development of specific drugs and transgenic mice have shown that enteric inhibitory responses depend upon P2Y1 receptors in post-junctional cells. The post-junctional cells that transduce purinergic neurotransmitters in the GI tract are PDGFRα+ cells and not smooth muscle cells (SMCs). PDGFRα+ cells express P2Y1 receptors, are activated by enteric inhibitory nerve stimulation and generate Ca2+ oscillations, express small-conductance Ca2+-activated K+ channels (SK3), and generate outward currents when exposed to P2Y1 agonists. These properties are consistent with post-junctional purinergic responses, and similar responses and effectors are not functional in SMCs. Refinements in methodologies to measure purines in tissue superfusates, such as high-performance liquid chromatography (HPLC) coupled with etheno-derivatization of purines and fluorescence detection, revealed that multiple purines are released during stimulation of intrinsic nerves. β-NAD+ and other purines, better satisfy criteria for the purinergic neurotransmitter than ATP. HPLC has also allowed better detection of purine metabolites, and coupled with isolation of specific types of post-junctional cells, has provided new concepts about deactivation of purine neurotransmitters. In spite of steady progress, many unknowns about purinergic neurotransmission remain and require additional investigation to understand this important regulatory mechanism in GI motility.
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Affiliation(s)
- Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, School of Medicine, 1664 North Virginia Street, Reno, NV 89557, USA.
| | - Violeta N Mutafova-Yambolieva
- Department of Physiology and Cell Biology, University of Nevada, School of Medicine, 1664 North Virginia Street, Reno, NV 89557, USA
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Sahakian L, Filippone RT, Stavely R, Robinson AM, Yan XS, Abalo R, Eri R, Bornstein JC, Kelley MR, Nurgali K. Inhibition of APE1/Ref-1 Redox Signaling Alleviates Intestinal Dysfunction and Damage to Myenteric Neurons in a Mouse Model of Spontaneous Chronic Colitis. Inflamm Bowel Dis 2020; 27:388-406. [PMID: 32618996 PMCID: PMC8287929 DOI: 10.1093/ibd/izaa161] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Inflammatory bowel disease (IBD) associates with damage to the enteric nervous system (ENS), leading to gastrointestinal (GI) dysfunction. Oxidative stress is important for the pathophysiology of inflammation-induced enteric neuropathy and GI dysfunction. Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) is a dual functioning protein that is an essential regulator of the cellular response to oxidative stress. In this study, we aimed to determine whether an APE1/Ref-1 redox domain inhibitor, APX3330, alleviates inflammation-induced oxidative stress that leads to enteric neuropathy in the Winnie murine model of spontaneous chronic colitis. METHODS Winnie mice received APX3330 or vehicle via intraperitoneal injections over 2 weeks and were compared with C57BL/6 controls. In vivo disease activity and GI transit were evaluated. Ex vivo experiments were performed to assess functional parameters of colonic motility, immune cell infiltration, and changes to the ENS. RESULTS Targeting APE1/Ref-1 redox activity with APX3330 improved disease severity, reduced immune cell infiltration, restored GI function ,and provided neuroprotective effects to the enteric nervous system. Inhibition of APE1/Ref-1 redox signaling leading to reduced mitochondrial superoxide production, oxidative DNA damage, and translocation of high mobility group box 1 protein (HMGB1) was involved in neuroprotective effects of APX3330 in enteric neurons. CONCLUSIONS This study is the first to investigate inhibition of APE1/Ref-1's redox activity via APX3330 in an animal model of chronic intestinal inflammation. Inhibition of the redox function of APE1/Ref-1 is a novel strategy that might lead to a possible application of APX3330 for the treatment of IBD.
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Affiliation(s)
- Lauren Sahakian
- Institute for Health and Sport, Victoria University; Western Centre for Health, Research and Education, Sunshine Hospital, Melbourne, Victoria, Australia
| | - Rhiannon T Filippone
- Institute for Health and Sport, Victoria University; Western Centre for Health, Research and Education, Sunshine Hospital, Melbourne, Victoria, Australia
| | - Rhian Stavely
- Institute for Health and Sport, Victoria University; Western Centre for Health, Research and Education, Sunshine Hospital, Melbourne, Victoria, Australia,Department of Pediatric Surgery, Pediatric Surgery Research Laboratories, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ainsley M Robinson
- Institute for Health and Sport, Victoria University; Western Centre for Health, Research and Education, Sunshine Hospital, Melbourne, Victoria, Australia
| | - Xu Sean Yan
- Institute for Health and Sport, Victoria University; Western Centre for Health, Research and Education, Sunshine Hospital, Melbourne, Victoria, Australia
| | - Raquel Abalo
- Área de Farmacología y Nutrición y Unidad Asociada al Instituto de Química Médica (IQM) del Consejo Superior de Investigaciones Científicas (CSIC), Universidad Rey Juan Carlos (URJC), Alcorcón, Madrid, Spain,High Performance Research Group in Physiopathology and Pharmacology of the Digestive System at URJC, Alcorcón, Madrid, Spain
| | - Rajaraman Eri
- University of Tasmania, School of Health Sciences, Launceston, Tasmania, Australia
| | - Joel C Bornstein
- Department of Physiology, Melbourne University, Melbourne, Australia
| | - Mark R Kelley
- Indiana University Simon Comprehensive Cancer Center, Departments of Pediatrics, Biochemistry & Molecular Biology and Pharmacology & Toxicology, Program in Pediatric Molecular Oncology & Experimental Therapeutics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine Indianapolis, USA
| | - Kulmira Nurgali
- Institute for Health and Sport, Victoria University; Western Centre for Health, Research and Education, Sunshine Hospital, Melbourne, Victoria, Australia,Department of Medicine Western Health, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia,Regenerative Medicine and Stem Cells Program, Australian Institute of Musculoskeletal Science (AIMSS), Melbourne, Victoria, Australia,Address correspondence to: Kulmira Nurgali, Level 4, Research Labs, Western Centre for Health Research & Education, Sunshine Hospital, 176 Furlong Road, St Albans, 3021, VIC, Australia. E-mail:
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White AR, Werner CM, Holmes GM. Diminished enteric neuromuscular transmission in the distal colon following experimental spinal cord injury. Exp Neurol 2020; 331:113377. [PMID: 32526238 DOI: 10.1016/j.expneurol.2020.113377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/14/2020] [Accepted: 06/03/2020] [Indexed: 12/30/2022]
Abstract
Neurogenic bowel following spinal cord injury (SCI) leads to decreased colonic motility, remodeling of the neuromuscular compartment and results in chronic evacuation difficulties. The distal colon of the rat serves a dual role for fluid absorption and storage that is homologous to the descending colon of humans. Dysmotility of the descending colon is one component of neurogenic bowel. We investigated the integrity of the enteric neuromuscular transmission responsible for the generation of excitatory and inhibitory junction potentials (EJPs and IJPs, respectively) in the distal colon of rats. We previously demonstrated a chronic reduction in colonic enteric neurons from rats with acute and chronic high-thoracic (T3) SCI and hypothesized that neurogenic bowel following T3-SCI results from diminished enteric neuromuscular transmission. Immunohistochemical labeling for myenteric neuronal nitric oxide synthase (nNOS) and choline acetyltransferase (ChAT) neurons demonstrated a significant loss of presumptive nitric oxide (NO) and acetylcholine (ACh) immunoreactive neurons in both 3-day and 3-week injured animals. Colonic neuromuscular transmission in response to transmural electrical stimulation of the colon was significantly reduced 3-days and 3-weeks following SCI in male rats. Specifically, cholinergic-mediated excitatory junction potentials (EJPs) and nitrergic-mediated slow inhibitory junction potentials (IJPs) were significantly reduced while ATP-mediated fast IJPs remained unaffected. We conclude that a reduction in excitatory and inhibitory enteric neuromuscular transmission contributes to neurogenic bowel observed following SCI, and that these loss-of-function changes involve enteric-mediated cholinergic and nitrergic pathways.
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Affiliation(s)
- Amanda R White
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA 17033, United States of America
| | - Claire M Werner
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA 17033, United States of America
| | - Gregory M Holmes
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA 17033, United States of America.
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Traserra S, Villarte S, Traini C, Palacin S, Vergara P, Vannucchi MG, Jimenez M. The asymmetric innervation of the circular and longitudinal muscle of the mouse colon differently modulates myogenic slow phasic contractions. Neurogastroenterol Motil 2020; 32:e13778. [PMID: 31845466 DOI: 10.1111/nmo.13778] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 11/07/2019] [Accepted: 11/25/2019] [Indexed: 01/06/2023]
Abstract
BACKGROUND Neuromuscular transmission has been extensively studied in the circular layer of the mouse colon where a co-transmission of purines acting on P2Y1 receptors and NO has been previously described. However, the corresponding mechanisms in the longitudinal layer are less known. METHODS Electrophysiological and myography techniques were used to evaluate spontaneous phasic contractions (SPC) and neural-mediated responses in the proximal, mid, and distal colon devoid of CD1 mice. Immunohistochemistry against c-kit and PDGFRα was performed in each colonic segment. KEY RESULTS SPC were recorded in both muscle layers at a similar frequency being about four contractions per minute (c.p.m.) in the proximal and distal colon compared to the mid colon (2 c.p.m.). In non-adrenergic, non-cholinergic conditions, L-NNA (1 mmol/L) increased contractility in the circular but not in the longitudinal layer. In the longitudinal muscle, both electrophysiological and mechanical neural-mediated inhibitory responses were L-NNA and ODQ (10 µmol/L) sensitive. NaNP (1 µmol/L) caused cessation of SPC and the response was blocked by ODQ. Neither ADPßS (10 µmol/L) nor CYPPA (10 µmol/L), which both targeted the purinergic pathway, altered longitudinal contractions. PDGFRα + cells were located in both muscle layers and were more numerous compared with cKit + cells, which both formed a heterologous cellular network. A decreasing gradient of the PDGFRα labeling was observed along the colon. CONCLUSION An inhibitory neural tone was absent in the longitudinal layer and neuronal inhibitory responses were mainly nitrergic. Despite the presence of PDGFRα + cells, purinergic responses were absent. Post-junctional pathways located in different cell types might be responsible for neurotransmitter transduction.
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Affiliation(s)
- Sara Traserra
- Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Sonia Villarte
- Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Chiara Traini
- Department of Experimental and Clinical Medicine, Research Unit of Histology and Embryology, University of Florence, Florence, Italy
| | - Sara Palacin
- Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Patri Vergara
- Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Maria Giuliana Vannucchi
- Department of Experimental and Clinical Medicine, Research Unit of Histology and Embryology, University of Florence, Florence, Italy
| | - Marcel Jimenez
- Department of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Barcelona, Spain
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Spear ET, Mawe GM. Enteric neuroplasticity and dysmotility in inflammatory disease: key players and possible therapeutic targets. Am J Physiol Gastrointest Liver Physiol 2019; 317:G853-G861. [PMID: 31604034 PMCID: PMC6962496 DOI: 10.1152/ajpgi.00206.2019] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Intestinal functions, including motility and secretion, are locally controlled by enteric neural networks housed within the wall of the gut. The fidelity of these functions depends on the precision of intercellular signaling among cellular elements, including enteric neurons, epithelial cells, immune cells, and glia, all of which are vulnerable to disruptive influences during inflammatory events. This review article describes current knowledge regarding inflammation-induced neuroplasticity along key elements of enteric neural circuits, what is known about the causes of these changes, and possible therapeutic targets for protecting and/or repairing the integrity of intrinsic enteric neurotransmission. Changes that have been detected in response to inflammation include increased epithelial serotonin availability, hyperexcitability of intrinsic primary afferent neurons, facilitation of synaptic activity among enteric neurons, and attenuated purinergic neuromuscular transmission. Dysfunctional propulsive motility has been detected in models of colitis, where causes include the changes described above, and in models of multiple sclerosis and other autoimmune conditions, where autoantibodies are thought to mediate dysmotility. Other cells implicated in inflammation-induced neuroplasticity include muscularis macrophages and enteric glia. Targeted treatments that are discussed include 5-hydroxytryptamine receptor 4 agonists, cyclooxygenase inhibitors, antioxidants, B cell depletion therapy, and activation of anti-inflammatory pathways.
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Affiliation(s)
- Estelle T. Spear
- 1Division of Gastroenterology and Hepatology, Department of Medicine, School of Medicine, Stanford University, Stanford, California
| | - Gary M. Mawe
- 2Department of Neurological Sciences, The University of Vermont, Burlington, Vermont
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Chami B, San Gabriel PT, Kum-Jew S, Wang X, Dickerhof N, Dennis JM, Witting PK. The nitroxide 4-methoxy-tempo inhibits the pathogenesis of dextran sodium sulfate-stimulated experimental colitis. Redox Biol 2019; 28:101333. [PMID: 31593888 PMCID: PMC6812268 DOI: 10.1016/j.redox.2019.101333] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 09/24/2019] [Accepted: 09/26/2019] [Indexed: 02/07/2023] Open
Abstract
Inflammatory bowel disease (IBD) is a chronic condition characterised by leukocyte recruitment to the gut mucosa. Leukocyte myeloperoxidase (MPO) produces the two-electron oxidant hypochlorous acid (HOCl), damaging tissue and playing a role in cellular recruitment, thereby exacerbating gut injury. We tested whether the MPO-inhibitor, 4-Methoxy-TEMPO (MetT), ameliorates experimental IBD. Colitis was induced in C57BL/6 mice by 3% w/v dextran-sodium-sulfate (DSS) in drinking water ad libitum over 9-days with MetT (15 mg/kg; via i. p. injection) or vehicle control (10% v/v DMSO+90% v/v phosphate buffered saline) administered twice daily during DSS challenge. MetT attenuated body-weight loss (50%, p < 0.05, n = 6), improved clinical score (53%, p < 0.05, n = 6) and inhibited serum lipid peroxidation. Histopathological damage decreased markedly in MetT-treated mice, as judged by maintenance of crypt integrity, goblet cell density and decreased cellular infiltrate. Colonic Ly6C+, MPO-labelled cells and 3-chlorotyrosine (3-Cl-Tyr) decreased in MetT-treated mice, although biomarkers for nitrosative stress (3-nitro-tyrosine-tyrosine; 3-NO2-Tyr) and low-molecular weight thiol damage (assessed as glutathione sulfonamide; GSA) were unchanged. Interestingly, MetT did not significantly impact colonic IL-10 and IL-6 levels, suggesting a non-immunomodulatory pathway. Overall, MetT ameliorated the severity of experimental IBD, likely via a mechanism involving the modulation of MPO-mediated damage.
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Affiliation(s)
- Belal Chami
- Discipline of Pathology, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Patrick T San Gabriel
- Discipline of Pathology, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Stephen Kum-Jew
- Discipline of Pathology, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - XiaoSuo Wang
- Discipline of Pathology, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Nina Dickerhof
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New Zealand
| | - Joanne M Dennis
- Discipline of Pathology, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Paul K Witting
- Discipline of Pathology, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia.
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13
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Holmes GM, Hubscher CH, Krassioukov A, Jakeman LB, Kleitman N. Recommendations for evaluation of bladder and bowel function in pre-clinical spinal cord injury research. J Spinal Cord Med 2019; 43:165-176. [PMID: 31556844 PMCID: PMC7054945 DOI: 10.1080/10790268.2019.1661697] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Objective: In order to encourage the inclusion of bladder and bowel outcome measures in preclinical spinal cord injury (SCI) research, this paper identifies and categorizes 1) fundamental, 2) recommended, 3) supplemental and 4) exploratory sets of outcome measures for pre-clinical assessment of bladder and bowel function with broad applicability to animal models of SCI.Methods: Drawing upon the collective research experience of autonomic physiologists and informed in consultation with clinical experts, a critical assessment of currently available bladder and bowel outcome measures (histological, biochemical, in vivo functional, ex vivo physiological and electrophysiological tests) was made to identify the strengths, deficiencies and ease of inclusion for future studies of experimental SCI.Results: Based upon pre-established criteria generated by the Neurogenic Bladder and Bowel Working Group that included history of use in experimental settings, citations in the literature by multiple independent groups, ease of general use, reproducibility and sensitivity to change, three fundamental measures each for bladder and bowel assessments were identified. Briefly defined, these assessments centered upon tissue morphology, voiding efficiency/volume and smooth muscle-mediated pressure studies. Additional assessment measures were categorized as recommended, supplemental or exploratory based upon the balance between technical requirements and potential mechanistic insights to be gained by the study.Conclusion: Several fundamental assessments share reasonable levels of technical and material investment, including some that could assess bladder and bowel function non-invasively and simultaneously. Such measures used more inclusively across SCI studies would advance progress in this high priority area. When complemented with a few additional investigator-selected study-relevant supplemental measures, they are highly recommended for research programs investigating the efficacy of therapeutic interventions in preclinical animal models of SCI that have a bladder and/or bowel focus.
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Affiliation(s)
- Gregory M. Holmes
- Neural and Behavioral Sciences, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA,Correspondence to: Gregory M. Holmes, Neural and Behavioral Sciences, Pennsylvania State University College of Medicine, 500 University Dr., Hershey, PA 17036, USA. ;
| | - Charles H. Hubscher
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, USA,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, USA
| | - Andrei Krassioukov
- ICORD, University of British Columbia, GF Strong Rehabilitation Centre, Vancouver, Canada
| | - Lyn B. Jakeman
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA
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14
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Grubišić V, Perez-Medina AL, Fried DE, Sévigny J, Robson SC, Galligan JJ, Gulbransen BD. NTPDase1 and -2 are expressed by distinct cellular compartments in the mouse colon and differentially impact colonic physiology and function after DSS colitis. Am J Physiol Gastrointest Liver Physiol 2019; 317:G314-G332. [PMID: 31188623 PMCID: PMC6774087 DOI: 10.1152/ajpgi.00104.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
ATP is both an important mediator of physiological gut functions such as motility and epithelial function, and a key danger signal that mediates cell death and tissue damage. The actions of extracellular ATP are regulated through the catalytic functions extracellular nucleoside triphosphate diphosphohydrolase-1 (NTPDase1), -2, -3, and -8, which ultimately generate nucleosides. Ectonucleotidases have distinct cellular associations, but the specific locations and functional roles of individual NTPDases in the intestine are still poorly understood. Here, we tested the hypothesis that differential and cell-selective regulation of purine hydrolysis by NTPDase1 and -2 plays important roles in gut physiology and disease. We studied Entpd1 and Entpd2 null mice in health and following colitis driven by 2% dextran sulfate sodium (DSS) administration using functional readouts of gut motility, epithelial barrier function, and neuromuscular communication. NTPDase1 is expressed by immune cells, and the ablation of Entpd1 altered glial numbers in the myenteric plexus. NTPDase2 is expressed by enteric glia, and the ablation of Entpd2 altered myenteric neuron numbers. Mice lacking either NTPDase1 or -2 exhibited decreased inhibitory neuromuscular transmission and altered components of inhibitory junction potentials. Ablation of Entpd2 increased gut permeability following inflammation. In conclusion, the location- and context-dependent extracellular nucleotide phosphohydrolysis by NTPDase1 and -2 substantially impacts gut function in health and disease.NEW & NOTEWORTHY Purines are important mediators of gastrointestinal physiology and pathophysiology. Nucleoside triphosphate diphosphohydrolases (NTPDases) regulate extracellular purines, but the roles of specific NTPDases in gut functions are poorly understood. Here, we used Entpd1- and Entpd2-deficient mice to show that the differential and cell-selective regulation of purine hydrolysis by NTPDase1 and -2 plays important roles in barrier function, gut motility, and neuromuscular communication in health and disease.
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Affiliation(s)
- Vladimir Grubišić
- 1Department of Physiology and Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Alberto L. Perez-Medina
- 2Department of Pharmacology and Toxicology and Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - David E. Fried
- 1Department of Physiology and Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Jean Sévigny
- 3Centre de recherche du CHU de Québec–Université Laval, Québec City, Quebec, Canada,4Département de Microbiologie-Infectiologie et d'Immunologie, Faculté de Médecine, Université Laval, Québec City, Quebec, Canada
| | - Simon C. Robson
- 5Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - James J. Galligan
- 2Department of Pharmacology and Toxicology and Neuroscience Program, Michigan State University, East Lansing, Michigan
| | - Brian D. Gulbransen
- 1Department of Physiology and Neuroscience Program, Michigan State University, East Lansing, Michigan
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15
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Lin Q, Qin M, Zhao SG, Liu ZX, Dou WJ, Zhang R, Li YL, Xi XH, Xu JQ, Ma LT, Wang JJ. The roles of PDGFRα signaling in the postnatal development and functional maintenance of the SMC-ICC-PDGFRα+ cell (SIP) syncytium in the colon. Neurogastroenterol Motil 2019; 31:e13568. [PMID: 30848008 DOI: 10.1111/nmo.13568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 01/15/2019] [Accepted: 01/15/2019] [Indexed: 01/02/2023]
Abstract
BACKGROUND The SIP syncytium in the gut consists of smooth muscle cells, interstitial cells of Cajal, and PDGFRα+ cells. We studied the fate of SIP cells after blocking PDGFRα receptor to explore the roles of PDGFRα signaling in the postnatal development and functional maintenance of the SIP syncytium. METHODS Crenolanib was administered to mice from P0, P10, or P50. The morphological changes in SIP cells were examined by immunofluorescence. Protein expression in SIP cells was detected by Western blotting. Moreover, colonic transit was analyzed by testing the colonic bead expulsion time. KEY RESULTS A dose of 5 mg(kg•day)-1 crenolanib administered for 10 days beginning on P0 apparently hindered the development of PDGFRα+ cells in the colonic longitudinal muscularis and myenteric plexus without influencing their proliferative activity and apoptosis, but this result was not seen in the colonic circular muscularis. SMCs were also inhibited by crenolanib. A dose of 7.5 mg(kg•day)-1 crenolanib administered for 15 days beginning on P0 caused reductions in both PDGFRα+ cells and ICC in the longitudinal muscularis, myenteric plexus, and circular muscularis. However, when crenolanib was administered at a dose of 5 mg(kg•day)-1 beginning on P10 or P50, it only noticeably decreased the number of PDGFRα+ cells in the colonic longitudinal muscularis. Crenolanib also caused PDGFRα+ cells to transdifferentiate into SMC in adult mice. Colonic transit was delayed after administration of crenolanib. CONCLUSIONS & INFERENCES Therefore, PDGFRα signaling is essential for the development and functional maintenance of the SIP cells, especially PDGFRα+ cells.
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Affiliation(s)
- Qiang Lin
- Department of Gastroenterology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Ming Qin
- Department of Gastroenterology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Shu-Guang Zhao
- Department of Gastroenterology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Zhen-Xiong Liu
- Department of Gastroenterology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Wei-Jia Dou
- Department of Gastroenterology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Rong Zhang
- Department of Gastroenterology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Yu-Long Li
- Department of Gastroenterology, Shaanxi Provincial People's Hospital, Xi'an, China
| | - Xiao-Hou Xi
- Department of Gastroenterology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Jia-Qiao Xu
- Department of Gastroenterology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Li-Tian Ma
- Department of Gastroenterology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Jing-Jie Wang
- Department of Gastroenterology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
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16
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Nyavor Y, Estill R, Edwards H, Ogden H, Heideman K, Starks K, Miller C, May G, Flesch L, McMillan J, Gericke M, Forney L, Balemba O. Intestinal nerve cell injury occurs prior to insulin resistance in female mice ingesting a high-fat diet. Cell Tissue Res 2019; 376:325-340. [PMID: 30778729 DOI: 10.1007/s00441-019-03002-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 01/30/2019] [Indexed: 12/11/2022]
Abstract
Diabetic patients suffer from gastrointestinal disorders associated with dysmotility, enteric neuropathy and dysbiosis of gut microbiota; however, gender differences are not fully known. Previous studies have shown that a high-fat diet (HFD) causes type two diabetes (T2D) in male mice after 4-8 weeks but only does so in female mice after 16 weeks. This study seeks to determine whether sex influences the development of intestinal dysmotility, enteric neuropathy and dysbiosis in mice fed HFD. We fed 8-week-old C57BL6 male and female mice a standard chow diet (SCD) or a 72% kcal HFD for 8 weeks. We analyzed the associations between sex and intestinal dysmotility, neuropathy and dysbiosis using motility assays, immunohistochemistry and next-generation sequencing. HFD ingestion caused obesity, glucose intolerance and insulin resistance in male but not female mice. However, HFD ingestion slowed intestinal propulsive motility in both male and female mice. This was associated with decreased inhibitory neuromuscular transmission, loss of myenteric inhibitory motor neurons and axonal swelling and loss of cytoskeletal filaments. HFD induced dysbiosis and changed the abundance of specific bacteria, especially Allobaculum, Bifidobacterium and Lactobacillus, which correlated with dysmotility and neuropathy. Female mice had higher immunoreactivity and numbers of myenteric inhibitory motor neurons, matching larger amplitudes of inhibitory junction potentials. This study suggests that sex influences the development of HFD-induced metabolic syndrome but dysmotility, neuropathy and dysbiosis occur independent of sex and prior to T2D conditions. Gastrointestinal dysmotility, neuropathy and dysbiosis might play a crucial role in the pathophysiology of T2D in humans irrespective of sex.
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Affiliation(s)
- Yvonne Nyavor
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA
| | - Rachel Estill
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA
| | - Hannah Edwards
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA
| | - Hailey Ogden
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA
| | - Kaila Heideman
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA
| | - Kiefer Starks
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA
| | - Christopher Miller
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA
| | - George May
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA
| | - Lance Flesch
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA
| | - John McMillan
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA
| | - Martin Gericke
- Institute for Anatomy, University of Leipzig, Liebigstraße 13, 04103, Leipzig, Germany
| | - Larry Forney
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA
| | - Onesmo Balemba
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, LSS 252, Moscow, ID, 83844, USA.
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17
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Gallego D, Malagelada C, Accarino A, Gori A, Malagelada JR, Azpiroz F, De Giorgio R, Jimenez M. Functional neuromuscular impairment in severe intestinal dysmotility. Neurogastroenterol Motil 2018; 30:e13458. [PMID: 30178519 DOI: 10.1111/nmo.13458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 07/18/2018] [Accepted: 08/06/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Chronic intestinal pseudo-obstruction (CIPO) and enteric dysmotility (ED) are severe intestinal motility disorders usually associated with underlying neuromuscular abnormalities. OBJECTIVE To evaluate the in vitro neuromuscular function of patients with severe intestinal motility disorders. METHODS Full-thickness intestinal biopsies (16 jejunum and 3 ileum) obtained from patients with CIPO (n = 10) and ED (n = 9) were studied using muscle bath and microelectrode techniques. Control samples (n = 6 ileum and n = 6 jejunum) were used to establish the range of normality. KEY RESULTS Fourteen parameters were defined to assess muscle contractility and nerve-muscle interaction: five to evaluate smooth muscle and interstitial cells of Cajal (ICC) and nine to evaluate inhibitory neuromuscular transmission. For each sample, a parameter was scored 0 if the value was inside the normal range or a value of 1 if it was outside. Patients' samples (CIPO/ED) had more abnormal parameters than controls (P < 0.001 for both jejunum and ileum). Functional abnormalities were found to be heterogeneous. The most prevalent abnormality was a decreased purinergic neuromuscular transmission, which was detected in 43.8% of jejunal samples. CONCLUSIONS AND INFERENCES Abnormalities of neuromuscular intestinal function are detected in vitro in severe intestinal dysmotility. However, consistent with the heterogeneity of the disease pathophysiology, functional impairment cannot be attributed to a single mechanism. Specifically, defects of purinergic neuromuscular transmission may have an important role in motility disorders of the gastrointestinal tract.
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Affiliation(s)
- Diana Gallego
- Department of Cell Biology, Physiology and Immunology and Neurosciences Institute, Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Spain
| | - Carolina Malagelada
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Spain.,Digestive System Research Unit, University Hospital Vall d'Hebron, Barcelona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Anna Accarino
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Spain.,Digestive System Research Unit, University Hospital Vall d'Hebron, Barcelona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Alessandra Gori
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Juan Ramón Malagelada
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Spain.,Digestive System Research Unit, University Hospital Vall d'Hebron, Barcelona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Fernando Azpiroz
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Spain.,Digestive System Research Unit, University Hospital Vall d'Hebron, Barcelona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | - Marcel Jimenez
- Department of Cell Biology, Physiology and Immunology and Neurosciences Institute, Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Spain
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18
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White AR, Holmes GM. Anatomical and Functional Changes to the Colonic Neuromuscular Compartment after Experimental Spinal Cord Injury. J Neurotrauma 2018; 35:1079-1090. [PMID: 29205096 DOI: 10.1089/neu.2017.5369] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A profound reduction in colorectal transit time accompanies spinal cord injury (SCI), yet the colonic alterations after SCI have yet to be understood fully. The loss of descending supraspinal input to lumbosacral neural circuits innervating the colon is recognized as one causal mechanism. Remodeling of the colonic enteric nervous system/smooth muscle junction in response to inflammation, however, is recognized as one factor leading to colonic dysmotility in other pathophysiological models. We investigated the alterations to the neuromuscular junction in rats with experimental high-thoracic (T3) SCI. One day to three weeks post-injury, both injured and age-matched controls underwent in vivo experimentation followed by tissue harvest for histological evaluation. Spontaneous colonic contractions were reduced significantly in the proximal and distal colon of T3-SCI rats. Histological evaluation of proximal and distal colon demonstrated significant reductions of colonic mucosal crypt depth and width. Markers of intestinal inflammation were assayed by qRT-PCR. Specifically, Icam1, Ccl2 (MCP-1), and Ccl3 (MIP-1α) mRNA was acutely elevated after T3-SCI. Smooth muscle thickness and collagen content of the colon were increased significantly in T3-SCI rats. Colonic cross sections immunohistochemically processed for the pan-neuronal marker HuC/D displayed a significant decrease in colonic enteric neuron density that became more pronounced at three weeks after injury. Our data suggest that post-SCI inflammation and remodeling of the enteric neuromuscular compartment accompanies SCI. These morphological changes may provoke the diminished colonic motility that occurs during this same period, possibly through the disruption of intrinsic neuromuscular control of the colon.
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Affiliation(s)
- Amanda R White
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine , Hershey, Pennsylvania
| | - Gregory M Holmes
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine , Hershey, Pennsylvania
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19
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El-Salhy M, Solomon T, Hausken T, Gilja OH, Hatlebakk JG. Gastrointestinal neuroendocrine peptides/amines in inflammatory bowel disease. World J Gastroenterol 2017; 23:5068-5085. [PMID: 28811704 PMCID: PMC5537176 DOI: 10.3748/wjg.v23.i28.5068] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/15/2017] [Accepted: 07/12/2017] [Indexed: 02/06/2023] Open
Abstract
Inflammatory bowel disease (IBD) is a chronic recurrent condition whose etiology is unknown, and it includes ulcerative colitis, Crohn’s disease, and microscopic colitis. These three diseases differ in clinical manifestations, courses, and prognoses. IBD reduces the patients’ quality of life and is an economic burden to both the patients and society. Interactions between the gastrointestinal (GI) neuroendocrine peptides/amines (NEPA) and the immune system are believed to play an important role in the pathophysiology of IBD. Moreover, the interaction between GI NEPA and intestinal microbiota appears to play also a pivotal role in the pathophysiology of IBD. This review summarizes the available data on GI NEPA in IBD, and speculates on their possible role in the pathophysiology and the potential use of this information when developing treatments. GI NEPA serotonin, the neuropeptide Y family, and substance P are proinflammatory, while the chromogranin/secretogranin family, vasoactive intestinal peptide, somatostatin, and ghrelin are anti-inflammatory. Several innate and adaptive immune cells express these NEPA and/or have receptors to them. The GI NEPA are affected in patients with IBD and in animal models of human IBD. The GI NEPA are potentially useful for the diagnosis and follow-up of the activity of IBD, and are candidate targets for treatments of this disease.
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20
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Purinergic Signalling in the Gut. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 891:91-112. [PMID: 27379638 DOI: 10.1007/978-3-319-27592-5_10] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The article will begin with the discovery of purinergic inhibitory neuromuscular transmission in the 1960s/1970s, the proposal for purinergic cotransmission in 1976 and the recognition that sympathetic nerves release adenosine 5'-triphosphate (ATP), noradrenaline and neuropeptide Y, while non-adrenergic, non-cholinergic inhibitory nerve cotransmitters are ATP, nitric oxide and vasoactive intestinal polypeptide in variable proportions in different regions of the gut. Later, purinergic synaptic transmission in the myenteric and submucosal plexuses was established and purinergic receptors expressed by both glial and interstitial cells. The focus will then be on purinergic mechanosensory transduction involving release of ATP from mucosal epithelial cells during distension to activate P2X3 receptors on submucosal sensory nerve endings. The responses of low threshold fibres mediate enteric reflex activity via intrinsic sensory nerves, while high threshold fibres initiate pain via extrinsic sensory nerves. Finally, the involvement of purinergic signalling in an animal model of colitis will be presented, showing that during distension there is increased ATP release, increased P2X3 receptor expression on calcitonin gene-related peptide-labelled sensory neurons and increased sensory nerve activity.
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21
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Lomax AE, Pradhananga S, Bertrand PP. Plasticity of neuroeffector transmission during bowel inflammation 1. Am J Physiol Gastrointest Liver Physiol 2017; 312:G165-G170. [PMID: 28082285 DOI: 10.1152/ajpgi.00365.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/03/2017] [Accepted: 01/03/2017] [Indexed: 01/31/2023]
Abstract
Altered gastrointestinal (GI) function contributes to the debilitating symptoms of inflammatory bowel diseases (IBD). Nerve circuits contained within the gut wall and outside of the gut play important roles in modulating motility, mucosal fluid transport, and blood flow. The structure and function of these neuronal populations change during IBD. Superimposed on this plasticity is a diminished responsiveness of effector cells - smooth muscle cells, enterocytes, and vascular endothelial cells - to neurotransmitters. The net result is a breakdown in the precisely orchestrated coordination of motility, fluid secretion, and GI blood flow required for health. In this review, we consider how inflammation-induced changes to the effector innervation of these tissues, and changes to the tissues themselves, contribute to defective GI function in models of IBD. We also explore the evidence that reversing neuronal plasticity is sufficient to normalize function during IBD.
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Affiliation(s)
- Alan E Lomax
- Gastrointestinal Disease Research Unit, Queen's University, Kingston, Ontario, Canada; and
| | - Sabindra Pradhananga
- Gastrointestinal Disease Research Unit, Queen's University, Kingston, Ontario, Canada; and
| | - Paul P Bertrand
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
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22
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Robinson AM, Rahman AA, Carbone SE, Randall-Demllo S, Filippone R, Bornstein JC, Eri R, Nurgali K. Alterations of colonic function in the Winnie mouse model of spontaneous chronic colitis. Am J Physiol Gastrointest Liver Physiol 2017; 312:G85-G102. [PMID: 27881401 DOI: 10.1152/ajpgi.00210.2016] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 11/14/2016] [Accepted: 11/14/2016] [Indexed: 01/31/2023]
Abstract
UNLABELLED The Winnie mouse, carrying a missense mutation in Muc2, is a model for chronic intestinal inflammation demonstrating symptoms closely resembling inflammatory bowel disease (IBD). Alterations to the immune environment, morphological structure, and innervation of Winnie mouse colon have been identified; however, analyses of intestinal transit and colonic functions have not been conducted. In this study, we investigated in vivo intestinal transit in radiographic studies and in vitro motility of the isolated colon in organ bath experiments. We compared neuromuscular transmission using conventional intracellular recording between distal colon of Winnie and C57BL/6 mice and smooth muscle contractions using force displacement transducers. Chronic inflammation in Winnie mice was confirmed by detection of lipocalin-2 in fecal samples over 4 wk and gross morphological damage to the colon. Colonic transit was faster in Winnie mice. Motility was altered including decreased frequency and increased speed of colonic migrating motor complexes and increased occurrence of short and fragmented contractions. The mechanisms underlying colon dysfunctions in Winnie mice included inhibition of excitatory and fast inhibitory junction potentials, diminished smooth muscle responses to cholinergic and nitrergic stimulation, and increased number of α-smooth muscle actin-immunoreactive cells. We conclude that diminished excitatory responses occur both prejunctionally and postjunctionally and reduced inhibitory purinergic responses are potentially a prejunctional event, while diminished nitrergic inhibitory responses are probably due to a postjunction mechanism in the Winnie mouse colon. Many of these changes are similar to disturbed motor functions in IBD patients indicating that the Winnie mouse is a model highly representative of human IBD. NEW & NOTEWORTHY This is the first study to provide analyses of intestinal transit and whole colon motility in an animal model of spontaneous chronic colitis. We found that cholinergic and purinergic neuromuscular transmission, as well as the smooth muscle cell responses to cholinergic and nitrergic stimulation, is altered in the chronically inflamed Winnie mouse colon. The changes to intestinal transit and colonic function we identified in the Winnie mouse are similar to those seen in inflammatory bowel disease patients.
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Affiliation(s)
- Ainsley M Robinson
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia
| | - Ahmed A Rahman
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia
| | - Simona E Carbone
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia
| | - Sarron Randall-Demllo
- University of Tasmania, School of Health Sciences, Launceston, Tasmania, Australia; and
| | - Rhiannon Filippone
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia
| | - Joel C Bornstein
- Department of Physiology, Melbourne University, Melbourne, Victoria, Australia
| | - Rajaraman Eri
- University of Tasmania, School of Health Sciences, Launceston, Tasmania, Australia; and
| | - Kulmira Nurgali
- College of Health and Biomedicine, Victoria University, Melbourne, Victoria, Australia;
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McQuade RM, Carbone SE, Stojanovska V, Rahman A, Gwynne RM, Robinson AM, Goodman CA, Bornstein JC, Nurgali K. Role of oxidative stress in oxaliplatin-induced enteric neuropathy and colonic dysmotility in mice. Br J Pharmacol 2016; 173:3502-3521. [PMID: 27714760 PMCID: PMC5120153 DOI: 10.1111/bph.13646] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 09/18/2016] [Accepted: 09/19/2016] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND AND PURPOSE Oxaliplatin is a platinum-based chemotherapeutic drug used as a first-line therapy for colorectal cancer. However, its use is associated with severe gastrointestinal side-effects resulting in dose limitations and/or cessation of treatment. In this study, we tested whether oxidative stress, caused by chronic oxaliplatin treatment, induces enteric neuronal damage and colonic dysmotility. EXPERIMENTAL APPROACH Oxaliplatin (3 mg·kg-1 per day) was administered in vivo to Balb/c mice intraperitoneally three times a week. The distal colon was collected at day 14 of treatment. Immunohistochemistry was performed in wholemount preparations of submucosal and myenteric ganglia. Neuromuscular transmission was studied by intracellular electrophysiology. Circular muscle tone was studied by force transducers. Colon propulsive activity studied in organ bath experiments and faeces were collected to measure water content. KEY RESULTS Chronic in vivo oxaliplatin treatment resulted in increased formation of reactive oxygen species (O2 -), nitration of proteins, mitochondrial membrane depolarisation resulting in the release of cytochrome c, loss of neurons, increased inducible NOS expression and apoptosis in both the submucosal and myenteric plexuses of the colon. Oxaliplatin treatment enhanced NO-mediated inhibitory junction potentials and altered the response of circular muscles to the NO donor, sodium nitroprusside. It also reduced the frequency of colonic migrating motor complexes and decreased circular muscle tone, effects reversed by the NO synthase inhibitor, Nω-Nitro-L-arginine. CONCLUSION AND IMPLICATIONS Our study is the first to provide evidence that oxidative stress is a key player in enteric neuropathy and colonic dysmotility leading to symptoms of chronic constipation observed in oxaliplatin-treated mice.
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Affiliation(s)
- Rachel M McQuade
- Centre for Chronic Disease, College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Simona E Carbone
- Centre for Chronic Disease, College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Vanesa Stojanovska
- Centre for Chronic Disease, College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Ahmed Rahman
- Centre for Chronic Disease, College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Rachel M Gwynne
- Department of Physiology, Melbourne University, Melbourne, Australia
| | - Ainsley M Robinson
- Centre for Chronic Disease, College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Craig A Goodman
- Centre for Chronic Disease, College of Health and Biomedicine, Victoria University, Melbourne, Australia
| | - Joel C Bornstein
- Department of Physiology, Melbourne University, Melbourne, Australia
| | - Kulmira Nurgali
- Centre for Chronic Disease, College of Health and Biomedicine, Victoria University, Melbourne, Australia
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24
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Spohn SN, Bianco F, Scott RB, Keenan CM, Linton AA, O’Neill CH, Bonora E, Dicay M, Lavoie B, Wilcox RL, MacNaughton WK, De Giorgio R, Sharkey KA, Mawe GM. Protective Actions of Epithelial 5-Hydroxytryptamine 4 Receptors in Normal and Inflamed Colon. Gastroenterology 2016; 151:933-944.e3. [PMID: 27480173 PMCID: PMC5159265 DOI: 10.1053/j.gastro.2016.07.032] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 06/16/2016] [Accepted: 07/06/2016] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS The 5-hydroxytryptamine receptor 4 (5-HT4R or HTR4) is expressed in the colonic epithelium but little is known about its functions there. We examined whether activation of colonic epithelial 5-HT4R protects colons of mice from inflammation. METHODS The 5-HT4R agonist tegaserod (1 mg/kg), the 5-HT4R antagonist GR113808 (1 mg/kg), or vehicle (control) were delivered by enema to wild-type or 5-HT4R knockout mice at the onset of, or during, active colitis, induced by administration of dextran sodium sulfate or trinitrobenzene sulfonic acid. Inflammation was measured using the colitis disease activity index and by histologic analysis of intestinal tissues. Epithelial proliferation, wound healing, and resistance to oxidative stress-induced apoptosis were assessed, as was colonic motility. RESULTS Rectal administration of tegaserod reduced the severity of colitis compared with mice given vehicle, and accelerated recovery from active colitis. Rectal tegaserod did not improve colitis in 5-HT4R knockout mice, and intraperitoneally administered tegaserod did not protect wild-type mice from colitis. Tegaserod increased proliferation of crypt epithelial cells. Stimulation of 5-HT4R increased Caco-2 cell migration and reduced oxidative stress-induced apoptosis; these actions were blocked by co-administration of the 5-HT4R antagonist GR113808. In noninflamed colons of wild-type mice not receiving tegaserod, inhibition of 5-HT4Rs resulted in signs of colitis within 3 days. In these mice, epithelial proliferation decreased and bacterial translocation to the liver and spleen was detected. Daily administration of tegaserod increased motility in inflamed colons of guinea pigs and mice, whereas administration of GR113808 disrupted motility in animals without colitis. CONCLUSIONS 5-HT4R activation maintains motility in healthy colons of mice and guinea pigs, and reduces inflammation in colons of mice with colitis. Agonists might be developed as treatments for patients with inflammatory bowel diseases.
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Affiliation(s)
| | - Francesca Bianco
- Department of Veterinary Medical Sciences,Department of Medical and Surgical Sciences, University of Bologna, Italy
| | | | - Catherine M. Keenan
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada,Snyder Institute for Chronic Diseases, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | | | | | - Elena Bonora
- Department of Medical and Surgical Sciences, University of Bologna, Italy
| | - Michael Dicay
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Brigitte Lavoie
- Neurological Sciences, University of Vermont, Burlington, VT
| | | | - Wallace K. MacNaughton
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Roberto De Giorgio
- Department of Medical and Surgical Sciences, University of Bologna, Italy
| | - Keith A. Sharkey
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada,Snyder Institute for Chronic Diseases, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Gary M. Mawe
- Neurological Sciences, University of Vermont, Burlington, VT
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25
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Mañé N, Jiménez-Sábado V, Jiménez M. BPTU, an allosteric antagonist of P2Y1 receptor, blocks nerve mediated inhibitory neuromuscular responses in the gastrointestinal tract of rodents. Neuropharmacology 2016; 110:376-385. [PMID: 27496690 DOI: 10.1016/j.neuropharm.2016.07.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 06/28/2016] [Accepted: 07/26/2016] [Indexed: 12/28/2022]
Abstract
P2Y1 receptors mediate nerve mediated purinergic inhibitory junction potentials (IJP) and relaxations in the gastrointestinal (GI) tract in a wide range of species including rodents and humans. A new P2Y1 antagonist, with a non-nucleotide structure, BPTU, has recently been described using X-ray crystallography as the first allosteric G-protein-coupled receptor antagonist located entirely outside of the helical bundle. In this study, we tested its effect on purinergic responses in the gastrointestinal tract of rodents using electrophysiological and myographic techniques. BPTU concentration dependently inhibited purinergic inhibitory junction potentials and inhibition of spontaneous motility induced by electrical field stimulation in the colon of rats (EC50 = 0.3 μM) and mice (EC50 = 0.06 μM). Mechanical inhibitory responses were also concentration-dependently blocked in the stomach of both species. Compared to MRS2500, BPTU displays a lower potency. In the rat colon nicotine induced relaxation was also blocked by BPTU. BPTU also blocked the cessation of spontaneous contractility elicited by ADPβS and the P2Y1 agonist MRS2365. We conclude that BPTU is a novel antagonist with different structural and functional properties than nucleotidic antagonists that is able to block the P2Y1 receptor located at the neuromuscular junction of the GI tract.
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Affiliation(s)
- Noemí Mañé
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute, Universitat Autònoma de Barcelona, Barcelona, Spain.
| | - Verónica Jiménez-Sábado
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute, Universitat Autònoma de Barcelona, Barcelona, Spain.
| | - Marcel Jiménez
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, (CIBERehd), Instituto de Salud Carlos III, Barcelona, Spain.
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26
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Margolis KG, Gershon MD. Enteric Neuronal Regulation of Intestinal Inflammation. Trends Neurosci 2016; 39:614-624. [PMID: 27450201 DOI: 10.1016/j.tins.2016.06.007] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 06/24/2016] [Accepted: 06/27/2016] [Indexed: 02/07/2023]
Abstract
Recent research has highlighted the importance of the two-way interaction between the nervous and immune systems. This interaction is particularly important in the bowel because of the unique properties of this organ. The lumen of the gut is lined by a very large but remarkably thin surface that separates the body from the enteric microbiome. Immune defenses against microbial invasion are thus well developed and neuroimmune interactions are important in regulating and integrating these defenses. Important concepts in the phylogeny of neuroimmunity, enteric neuronal and glial regulation of immunity, changes that occur in the enteric nervous system during inflammation, the fundamental role of serotonin (5-HT) in enteric neuroimmune mechanisms, and future perspectives are reviewed.
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Affiliation(s)
- Kara Gross Margolis
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, 620 West 168th Street, New York, NY 10032, USA
| | - Michael D Gershon
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, 650 West 168th Street, New York, NY 10032, USA.
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27
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Bubenheimer RK, Brown IAM, Fried DE, McClain JL, Gulbransen BD. Sirtuin-3 Is Expressed by Enteric Neurons but It Does not Play a Major Role in Their Regulation of Oxidative Stress. Front Cell Neurosci 2016; 10:73. [PMID: 27047337 PMCID: PMC4801875 DOI: 10.3389/fncel.2016.00073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 03/08/2016] [Indexed: 12/30/2022] Open
Abstract
Gut inflammation contributes to the development of gut motility disorders in part by disrupting the function and survival of enteric neurons through mechanisms that involve oxidative stress. How enteric neurons regulate oxidative stress is still poorly understood. Importantly, how neuron autonomous antioxidant mechanisms contribute to the susceptibility of enteric neurons to oxidative stress in disease is not known. Here, we discover that sirtuin-3 (Sirt3), a key regulator of oxidative stress and mitochondrial metabolism, is expressed by neurons in the enteric nervous system (ENS) of the mouse colon. Given the important role of Sirt3 in the regulation of neuronal oxidative stress in the central nervous system (CNS), we hypothesized that Sirt3 plays an important role in the cell autonomous regulation of oxidative stress by enteric neurons and that a loss of Sirt3 increases neuronal vulnerability during intestinal inflammation. We tested our hypothesis using a combination of traditional immunohistochemistry, oxidative stress measurements and in vivo and ex vivo measures of GI motility in healthy and inflamed wild-type (wt) and Sirt3 null (Sirt3−/−) mice. Our results show that Sirt3 is widely expressed by neurons throughout the myenteric plexus of the mouse colon. However, the deletion of Sirt3 had surprisingly little effect on gut function and susceptibility to inflammation. Likewise, neither the genetic ablation of Sirt3 nor the inhibition of Sirt3 with antagonists had a significant effect on neuronal oxidative stress. Therefore, we conclude that Sirt3 contributes very little to the overall regulation of neuronal oxidative stress in the ENS. The functional relevance of Sirt3 in enteric neurons is still unclear but our data show that it is an unlikely candidate to explain neuronal vulnerability to oxidative stress during inflammation.
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Affiliation(s)
- Rebecca K Bubenheimer
- Neuroscience Program, Michigan State UniversityEast Lansing, MI, USA; Department of Physiology, Michigan State UniversityEast Lansing, MI, USA
| | - Isola A M Brown
- Department of Physiology, Michigan State UniversityEast Lansing, MI, USA; Pharmacology and Toxicology Program, Michigan State UniversityEast Lansing, MI, USA
| | - David E Fried
- Department of Physiology, Michigan State University East Lansing, MI, USA
| | - Jonathon L McClain
- Department of Physiology, Michigan State University East Lansing, MI, USA
| | - Brian D Gulbransen
- Neuroscience Program, Michigan State UniversityEast Lansing, MI, USA; Department of Physiology, Michigan State UniversityEast Lansing, MI, USA
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28
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Vanner S, Greenwood-Van Meerveld B, Mawe G, Shea-Donohue T, Verdu EF, Wood J, Grundy D. Fundamentals of Neurogastroenterology: Basic Science. Gastroenterology 2016; 150:S0016-5085(16)00184-0. [PMID: 27144618 PMCID: PMC5673591 DOI: 10.1053/j.gastro.2016.02.018] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 02/09/2016] [Indexed: 02/07/2023]
Abstract
This review examines the fundamentals of neurogastroenterology that may underlie the pathophysiology of functional GI disorders (FGIDs). It was prepared by an invited committee of international experts and represents an abbreviated version of their consensus document that will be published in its entirety in the forthcoming book and online version entitled ROME IV. It emphasizes recent advances in our understanding of the enteric nervous system, sensory physiology underlying pain, and stress signaling pathways. There is also a focus on neuroimmmune signaling and intestinal barrier function, given the recent evidence implicating the microbiome, diet, and mucosal immune activation in FGIDs. Together, these advances provide a host of exciting new targets to identify and treat FGIDs and new areas for future research into their pathophysiology.
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Affiliation(s)
- Stephen Vanner
- Gastrointestinal Diseases Research Unit, Kingston General Hospital, Kingston, Ontario, Canada.
| | - Beverley Greenwood-Van Meerveld
- Oklahoma Center for Neuroscience, Department of Physiology, VA Medical Center, University of Oklahoma, Health Sciences Center, Oklahoma City, Oklahoma
| | - Gary Mawe
- Department of Neurological Sciences, Pharmacology and Medicine Division, Gastroenterology and Hepatology, University of Vermont, Burlington, Vermont
| | - Terez Shea-Donohue
- Department of Medicine and Physiology, University of Maryland, School of Medicine, Baltimore, Maryland
| | - Elena F Verdu
- Farncombe Family Digestive Health Research Institute, McMaster University, Health Sciences Center, Hamilton, Ontario, Canada
| | - Jackie Wood
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - David Grundy
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
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29
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Shang B, Shi H, Wang X, Guo X, Wang N, Wang Y, Dong L. Protective effect of melatonin on myenteric neuron damage in experimental colitis in rats. Fundam Clin Pharmacol 2016; 30:117-27. [PMID: 26787455 DOI: 10.1111/fcp.12181] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 12/28/2015] [Accepted: 01/13/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Boxin Shang
- Department of Gastroenterology; Second Affiliated Hospital of Xi'an Jiaotong University; Xi'an 710004 Shaanxi Province China
| | - Haitao Shi
- Department of Gastroenterology; Second Affiliated Hospital of Xi'an Jiaotong University; Xi'an 710004 Shaanxi Province China
| | - Xiaoyan Wang
- Department of Gastroenterology; Second Affiliated Hospital of Xi'an Jiaotong University; Xi'an 710004 Shaanxi Province China
| | - Xiaoyan Guo
- Department of Gastroenterology; Second Affiliated Hospital of Xi'an Jiaotong University; Xi'an 710004 Shaanxi Province China
| | - Nan Wang
- Department of Gastroenterology; Second Affiliated Hospital of Xi'an Jiaotong University; Xi'an 710004 Shaanxi Province China
| | - Yan Wang
- Department of Gastroenterology; Second Affiliated Hospital of Xi'an Jiaotong University; Xi'an 710004 Shaanxi Province China
| | - Lei Dong
- Department of Gastroenterology; Second Affiliated Hospital of Xi'an Jiaotong University; Xi'an 710004 Shaanxi Province China
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30
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Mas M, Mañé N, Fernández F, Gallego D, Pumarola M, Jiménez M. P2Y(1) receptors mediate purinergic relaxation in the equine pelvic flexure. Vet J 2016; 209:74-81. [PMID: 26831180 DOI: 10.1016/j.tvjl.2016.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 11/11/2015] [Accepted: 01/01/2016] [Indexed: 12/12/2022]
Abstract
In the equine large intestine, the knowledge of the basic mechanisms underlying motility function is crucial to properly treat motility disorders. P2Y1 receptors are responsible for mediating purinergic colonic relaxation in several species. In vitro experimental studies of the circular muscle from the equine pelvic flexure (n = 6) were performed to characterize inhibitory and excitatory neuromuscular transmission. Electrophysiological studies showed that electrical field stimulation (EFS) evoked biphasic inhibitory junction potentials (IJPs) in smooth muscle cells: a fast IJP (IJPf) followed by a sustained IJP (IJPs). IJPs was sensitive to L-NNA 1 mM (a nitric oxide synthase inhibitor) (P <0.01), while IJPf was abolished by MRS2500 1 µM (a P2Y1 receptor antagonist) (P <0.001). EFS (5 Hz for 2 min) in the organ bath inhibited rhythmic contractions to 3.0 ± 2.5% of basal area under the curve (P <0.0001). EFS under MRS2500 1 µM or L-NNA 1 mM incubation inhibited contractions to 6.0 ± 2.8% (P <0.05) and 24.4 ± 11.3% respectively (P <0.05). Combination of MRS2500 1 µM and L-NNA 1 mM completely reversed the EFS-induced inhibition of colonic motility. Non-nitrergic, non-purinergic conditions were used to reveal voltage-dependent EFS-induced contractions sensitive to atropine 1 µM (P <0.001) and, therefore, cholinergic. In conclusion, nerve-mediated relaxation and contraction in the equine pelvic flexure involve the same mechanisms as those observed in the human colon. P2Y1 receptors mediate purinergic relaxations and are potential targets for the treatment of equine colonic motor disorders.
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Affiliation(s)
- M Mas
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - N Mañé
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - F Fernández
- Department of Animal Medicine and Surgery, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - D Gallego
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Barcelona, Spain
| | - M Pumarola
- Department of Animal Medicine and Surgery, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - M Jiménez
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Barcelona, Spain.
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31
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The Intrinsic Reflex Circuitry of the Inflamed Colon. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 891:153-7. [DOI: 10.1007/978-3-319-27592-5_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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32
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Singh J, Kumar S, Rattan S. Bimodal effect of oxidative stress in internal anal sphincter smooth muscle. Am J Physiol Gastrointest Liver Physiol 2015; 309:G292-300. [PMID: 26138467 PMCID: PMC4556951 DOI: 10.1152/ajpgi.00125.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 06/29/2015] [Indexed: 01/31/2023]
Abstract
Changes in oxidative stress may affect basal tone and relaxation of the internal anal sphincter (IAS) smooth muscle in aging. We examined this issue by investigating the effects of the oxidative stress inducer 6-anilino-5,8-quinolinedione (LY-83583) in basal as well as U-46619-stimulated tone, and nonadrenergic, noncholinergic (NANC) relaxation in rat IAS. LY-83583, which works via generation of reactive oxygen species in living cells, produced a bimodal effect in IAS tone: lower concentrations (0.1 nM to 10 μM) produced a concentration-dependent increase, while higher concentrations (50-100 μM) produced a decrease in IAS tone. An increase in IAS tone by lower concentrations was associated with an increase in RhoA/Rho kinase (ROCK) activity. This was evident by the increase in RhoA/ROCK in the particulate fractions, in ROCK activity, and in the levels of phosphorylated (p) (Thr696)-myosin phosphatase target subunit 1 and p(Thr18/Ser19)-20-kDa myosin light chain. Conversely, higher concentrations of LY-83583 produced inhibitory effects on RhoA/ROCK. Interestingly, both the excitatory and inhibitory effects of LY-83583 in the IAS were reversed by superoxide dismutase. The excitatory effects of LY-83583 were found to resemble those with neuronal nitric oxide synthase (nNOS) inhibition by l-NNA, since it produced a significant increase in the IAS tone and attenuated NANC relaxation. These effects of LY-83583 and l-NNA were reversible by l-arginine. This suggests the role of nNOS inhibition and RhoA/ROCK activation in the increase in IAS tone by LY-83583. These data have important implications in the pathophysiology and therapeutic targeting of rectoanal disorders, especially associated with IAS dysfunction.
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Affiliation(s)
- Jagmohan Singh
- Division of Gastroenterology and Hepatology, Department of Medicine, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sumit Kumar
- Division of Gastroenterology and Hepatology, Department of Medicine, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Satish Rattan
- Division of Gastroenterology and Hepatology, Department of Medicine, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania
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33
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The effects of tempol on cyclophosphamide-induced oxidative stress in rat micturition reflexes. ScientificWorldJournal 2015; 2015:545048. [PMID: 25973443 PMCID: PMC4417973 DOI: 10.1155/2015/545048] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/03/2015] [Accepted: 03/05/2015] [Indexed: 11/18/2022] Open
Abstract
We hypothesized that cyclophosphamide- (CYP-) induced cystitis results in oxidative stress and contributes to urinary bladder dysfunction. We determined (1) the expression of oxidative stress markers 3-nitrotyrosine (3-NT), reactive oxygen species (ROS)/reactive nitrogen species (RNS), inflammatory modulators, neuropeptides calcitonin gene-related peptide (CGRP), substance P (Sub P), and adenosine triphosphate (ATP) that contribute to the inflammatory process in the urinary tract and (2) the functional role of oxidative stress in urinary bladder dysfunction with an antioxidant, Tempol, (1 mM in drinking water) combined with conscious cystometry. In CYP-treated (4 hr or 48 hr; 150 mg/kg, i.p.) rats, ROS/RNS and 3-NT significantly (P ≤ 0.01) increased in urinary bladder. CYP treatment increased ATP, Sub P, and CGRP expression in the urinary bladder and cystometric fluid. In CYP-treated rats, Tempol significantly (P ≤ 0.01) increased bladder capacity and reduced voiding frequency compared to CYP-treated rats without Tempol. Tempol significantly (P ≤ 0.01) reduced ATP expression, 3-NT, and ROS/RNS expression in the urinary tract of CYP-treated rats. These studies demonstrate that reducing oxidative stress in CYP-induced cystitis improves urinary bladder function and reduces markers of oxidative stress and inflammation.
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34
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Mawe GM. Colitis-induced neuroplasticity disrupts motility in the inflamed and post-inflamed colon. J Clin Invest 2015; 125:949-55. [PMID: 25729851 DOI: 10.1172/jci76306] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Effective colonic motility involves an intricate pattern of excitatory and inhibitory neuromuscular signals that arise from the enteric neural circuitry of the colon. Recent investigations have demonstrated that inflammation leads to a variety of changes in the physiological properties of the neurons in this circuitry, including hyperexcitability of neurons at the afferent end of the peristaltic reflex, synaptic facilitation, and attenuated inhibitory neuromuscular transmission. Furthermore, links have been established between these changes and disrupted motor activity in the colon, and we now know that some of these changes persist long after recovery from inflammation. It is highly likely that inflammation-induced neuroplasticity, which is not detectable by clinical diagnostics, contributes to disrupted motility in active and quiescent inflammatory bowel disease and in functional gastrointestinal disorders.
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Mutafova-Yambolieva VN, Durnin L. The purinergic neurotransmitter revisited: a single substance or multiple players? Pharmacol Ther 2014; 144:162-91. [PMID: 24887688 PMCID: PMC4185222 DOI: 10.1016/j.pharmthera.2014.05.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 05/23/2014] [Indexed: 12/20/2022]
Abstract
The past half century has witnessed tremendous advances in our understanding of extracellular purinergic signaling pathways. Purinergic neurotransmission, in particular, has emerged as a key contributor in the efficient control mechanisms in the nervous system. The identity of the purine neurotransmitter, however, remains controversial. Identifying it is difficult because purines are present in all cell types, have a large variety of cell sources, and are released via numerous pathways. Moreover, studies on purinergic neurotransmission have relied heavily on indirect measurements of integrated postjunctional responses that do not provide direct information for neurotransmitter identity. This paper discusses experimental support for adenosine 5'-triphosphate (ATP) as a neurotransmitter and recent evidence for possible contribution of other purines, in addition to or instead of ATP, in chemical neurotransmission in the peripheral, enteric and central nervous systems. Sites of release and action of purines in model systems such as vas deferens, blood vessels, urinary bladder and chromaffin cells are discussed. This is preceded by a brief discussion of studies demonstrating storage of purines in synaptic vesicles. We examine recent evidence for cell type targets (e.g., smooth muscle cells, interstitial cells, neurons and glia) for purine neurotransmitters in different systems. This is followed by brief discussion of mechanisms of terminating the action of purine neurotransmitters, including extracellular nucleotide hydrolysis and possible salvage and reuptake in the cell. The significance of direct neurotransmitter release measurements is highlighted. Possibilities for involvement of multiple purines (e.g., ATP, ADP, NAD(+), ADP-ribose, adenosine, and diadenosine polyphosphates) in neurotransmission are considered throughout.
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Affiliation(s)
| | - Leonie Durnin
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, United States
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Jiménez M, Clavé P, Accarino A, Gallego D. Purinergic neuromuscular transmission in the gastrointestinal tract; functional basis for future clinical and pharmacological studies. Br J Pharmacol 2014; 171:4360-75. [PMID: 24910216 DOI: 10.1111/bph.12802] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 05/14/2014] [Accepted: 05/24/2014] [Indexed: 12/13/2022] Open
Abstract
Nerve-mediated relaxation is necessary for the correct accomplishment of gastrointestinal (GI) motility. In the GI tract, NO and a purine are probably released by the same inhibitory motor neuron as inhibitory co-transmitters. The P2Y1 receptor has been recently identified as the receptor responsible for purinergic smooth muscle hyperpolarization and relaxation in the human gut. This finding has been confirmed in P2Y1 -deficient mice where purinergic neurotransmission is absent and transit time impaired. However, the mechanisms responsible for nerve-mediated relaxation, including the identification of the purinergic neurotransmitter(s) itself, are still debatable. Possibly different mechanisms of nerve-mediated relaxation are present in the GI tract. Functional demonstration of purinergic neuromuscular transmission has not been correlated with structural studies. Labelling of purinergic neurons is still experimental and is not performed in routine pathology studies from human samples, even when possible neuromuscular impairment is suspected. Accordingly, the contribution of purinergic neurotransmission in neuromuscular diseases affecting GI motility is not known. In this review, we have focused on the physiological mechanisms responsible for nerve-mediated purinergic relaxation providing the functional basis for possible future clinical and pharmacological studies on GI motility targeting purine receptors.
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Affiliation(s)
- Marcel Jiménez
- Department of Cell Biology, Physiology and Immunology, Neurosciences Institute, Universitat Autònoma de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Barcelona, Spain
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Ochoa-Cortes F, Liñán-Rico A, Jacobson KA, Christofi FL. Potential for developing purinergic drugs for gastrointestinal diseases. Inflamm Bowel Dis 2014; 20:1259-87. [PMID: 24859298 PMCID: PMC4340257 DOI: 10.1097/mib.0000000000000047] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Treatments for inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), functional dyspepsia, or motility disorders are not adequate, and purinergic drugs offer exciting new possibilities. Gastrointestinal symptoms that could be targeted for therapy include visceral pain, inflammatory pain, dysmotility, constipation, and diarrhea. The focus of this review is on the potential for developing purinergic drugs for clinical trials to treat gastrointestinal symptoms. Purinergic receptors are divided into adenosine P1 (A(1), A(2A), A(2B), A(3)), ionotropic ATP-gated P2X ion channel (P2X(1-7)), or metabotropic P2Y(1,2,4,6,11-14) receptors. There is good experimental evidence for targeting A(2A), A(2B), A(3), P2X(7), and P2X(3) receptors or increasing endogenous adenosine levels to treat IBD, inflammatory pain, IBS/visceral pain, inflammatory diarrhea, and motility disorders. Purine genes are also potential biomarkers of disease. Advances in medicinal chemistry have an accelerated pace toward clinical trials: Methotrexate and sulfasalazine, used to treat IBD, act by stimulating CD73-dependent adenosine production. ATP protects against NSAID-induced enteropathy and has pain-relieving properties in humans. A P2X(7)R antagonist AZD9056 is in clinical trials for Crohn's disease. A(3) adenosine receptor drugs target inflammatory diseases (e.g., CF101, CF102). Dipyridamole, a nucleoside uptake inhibitor, is in trials for endotoxemia. Drugs for pain in clinical trials include P2X(3)/P2X(2/3) (AF-219) and P2X(7) (GSK1482160) antagonists and A(1) (GW493838) or A(2A) (BVT.115959) agonists. Iberogast is a phytopharmacon targeting purine mechanisms with efficacy in IBS and functional dyspepsia. Purinergic drugs have excellent safety/efficacy profile for prospective clinical trials in IBD, IBS, functional dyspepsia, and inflammatory diarrhea. Genetic polymorphisms and caffeine consumption may affect susceptibility to treatment. Further studies in animals can clarify mechanisms and test new generation drugs. Finally, there is still a huge gap in our knowledge of human pathophysiology of purinergic signaling.
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Affiliation(s)
- Fernando Ochoa-Cortes
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, Columbus, Ohio
| | - Andromeda Liñán-Rico
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, Columbus, Ohio
| | - Kenneth A. Jacobson
- Laboratory of Bioorganic Chemistry & Molecular Recognition Section, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health
| | - Fievos L. Christofi
- Department of Anesthesiology, The Wexner Medical Center at The Ohio State University, Columbus, Ohio
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Singh J, Kumar S, Krishna CV, Rattan S. Aging-associated oxidative stress leads to decrease in IAS tone via RhoA/ROCK downregulation. Am J Physiol Gastrointest Liver Physiol 2014; 306:G983-91. [PMID: 24742984 PMCID: PMC4042111 DOI: 10.1152/ajpgi.00087.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Internal anal sphincter (IAS) tone plays an important role in rectoanal incontinence (RI). IAS tone may be compromised during aging, leading to RI in certain patients. We examined the influence of oxidative stress in the aging-associated decrease in IAS tone (AADI). Using adult (4-6 mo old) and aging (24-30 mo old) rats, we determined the effect of oxidative stress on IAS tone and the regulatory RhoA/ROCK signal transduction cascade. We determined the effect of the oxidative stress inducer LY83583, which produces superoxide anions (O2 (·-)), on basal and stimulated IAS tone before and after treatment of intact smooth muscle strips and smooth muscle cells with the O2 (·-) scavenger SOD. Our data showed that AADI was associated with a decrease in RhoA/ROCK expression at the transcriptional and translational levels. Oxidative stress with a LY83583-mediated decrease in IAS tone and relaxation of IAS smooth muscle cells was associated with a decrease in RhoA/ROCK signal transduction, which was reversible by SOD. In addition, LY83583 caused a significant decrease in IAS contraction produced by the RhoA activator and a known RhoA/ROCK agonist, U46619, that was also reversible by SOD. The inhibitory effects of LY83583 and the ROCK inhibitor Y27632 on the U46619-induced increase in IAS tone were similar. We conclude that an increase in oxidative stress plays an important role in AADI in the elderly and may be one of the underlying mechanisms of RI in certain aging patients.
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Affiliation(s)
| | | | | | - Satish Rattan
- Division of Gastroenterology and Hepatology, Department of Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
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