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Remme CA. SCN5A channelopathy: arrhythmia, cardiomyopathy, epilepsy and beyond. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220164. [PMID: 37122208 PMCID: PMC10150216 DOI: 10.1098/rstb.2022.0164] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 12/31/2022] [Indexed: 05/02/2023] Open
Abstract
Influx of sodium ions through voltage-gated sodium channels in cardiomyocytes is essential for proper electrical conduction within the heart. Both acquired conditions associated with sodium channel dysfunction (myocardial ischaemia, heart failure) as well as inherited disorders secondary to mutations in the gene SCN5A encoding for the cardiac sodium channel Nav1.5 are associated with life-threatening arrhythmias. Research in the last decade has uncovered the complex nature of Nav1.5 distribution, function, in particular within distinct subcellular subdomains of cardiomyocytes. Nav1.5-based channels furthermore display previously unrecognized non-electrogenic actions and may impact on cardiac structural integrity, leading to cardiomyopathy. Moreover, SCN5A and Nav1.5 are expressed in cell types other than cardiomyocytes as well as various extracardiac tissues, where their functional role in, e.g. epilepsy, gastrointestinal motility, cancer and the innate immune response is increasingly investigated and recognized. This review provides an overview of these novel insights and how they deepen our mechanistic knowledge on SCN5A channelopathies and Nav1.5 (dys)function. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- Carol Ann Remme
- Department of Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam UMC location AMC, University of Amsterdam, Amsterdam, The Netherlands
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2
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Pandey Y, Dondapati SK, Kubick S. Enriched cell-free and cell-based native membrane derived vesicles (nMV) enabling rapid in-vitro electrophysiological analysis of the voltage-gated sodium channel 1.5. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184144. [PMID: 36889502 DOI: 10.1016/j.bbamem.2023.184144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/10/2023] [Accepted: 02/28/2023] [Indexed: 03/08/2023]
Abstract
Here, we demonstrate the utility of native membrane derived vesicles (nMVs) as tools for expeditious electrophysiological analysis of membrane proteins. We used a cell-free (CF) and a cell-based (CB) approach for preparing protein-enriched nMVs. We utilized the Chinese Hamster Ovary (CHO) lysate-based cell-free protein synthesis (CFPS) system to enrich ER-derived microsomes in the lysate with the primary human cardiac voltage-gated sodium channel 1.5 (hNaV1.5; SCN5A) in 3 h. Subsequently, CB-nMVs were isolated from fractions of nitrogen-cavitated CHO cells overexpressing the hNaV1.5. In an integrative approach, nMVs were micro-transplanted into Xenopus laevis oocytes. CB-nMVs expressed native lidocaine-sensitive hNaV1.5 currents within 24 h; CF-nMVs did not elicit any response. Both the CB- and CF-nMV preparations evoked single-channel activity on the planar lipid bilayer while retaining sensitivity to lidocaine application. Our findings suggest a high usability of the quick-synthesis CF-nMVs and maintenance-free CB-nMVs as ready-to-use tools for in-vitro analysis of electrogenic membrane proteins and large, voltage-gated ion channels.
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Affiliation(s)
- Yogesh Pandey
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany; Institut für Biochemie und Biologie, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam OT Golm, Germany
| | - Srujan Kumar Dondapati
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany.
| | - Stefan Kubick
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany; Technische Universität Berlin, Institute of Biotechnology, Straße des 17. Juni 135, 10623 Berlin, Germany; Freie Universität Berlin, Institute of Chemistry and Biochemistry, 14195 Berlin, Germany; Faculty of Health Science, Joint Faculty of the Brandenburg University of Technology Cottbus-Senftenberg, the Brandenburg Medical School Theodor Fontane and the University of Potsdam, Germany
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3
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Zhao F, Fang L, Wang Q, Ye Q, He Y, Xu W, Song Y. Exploring the Pivotal Components Influencing the Side Effects Induced by an Analgesic-Antitumor Peptide from Scorpion Venom on Human Voltage-Gated Sodium Channels 1.4 and 1.5 through Computational Simulation. Toxins (Basel) 2022; 15:33. [PMID: 36668853 PMCID: PMC9864070 DOI: 10.3390/toxins15010033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023] Open
Abstract
Voltage-gated sodium channels (VGSCs, or Nav) are important determinants of action potential generation and propagation. Efforts are underway to develop medicines targeting different channel subtypes for the treatment of related channelopathies. However, a high degree of conservation across its nine subtypes could lead to the off-target adverse effects on skeletal and cardiac muscles due to acting on primary skeletal muscle sodium channel Nav1.4 and cardiac muscle sodium channel Nav1.5, respectively. For a long evolutionary process, some peptide toxins from venoms have been found to be highly potent yet selective on ion channel subtypes and, therefore, hold the promising potential to be developed into therapeutic agents. In this research, all-atom molecular dynamic methods were used to elucidate the selective mechanisms of an analgesic-antitumor β-scorpion toxin (AGAP) with human Nav1.4 and Nav1.5 in order to unravel the primary reason for the production of its adverse reactions on the skeletal and cardiac muscles. Our results suggest that the rational distribution of residues with ring structures near position 38 and positive residues in the C-terminal on AGAP are critical factors to ensure its analgesic efficacy. Moreover, the substitution for residues with benzene is beneficial to reduce its side effects.
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Affiliation(s)
- Fan Zhao
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, China
| | - Liangyi Fang
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, China
| | - Qi Wang
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, China
| | - Qi Ye
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, China
| | - Yanan He
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, China
| | - Weizhuo Xu
- Faculty of Functional Food and Wine, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, China
| | - Yongbo Song
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenyang 110016, China
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Cowan LM, Strege PR, Rusinova R, Andersen OS, Farrugia G, Beyder A. Capsaicin as an amphipathic modulator of Na V1.5 mechanosensitivity. Channels (Austin) 2022; 16:9-26. [PMID: 35412435 PMCID: PMC9009938 DOI: 10.1080/19336950.2022.2026015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
SCN5A-encoded NaV1.5 is a voltage-gated Na+ channel that drives the electrical excitability of cardiac myocytes and contributes to slow waves of the human gastrointestinal smooth muscle cells. NaV1.5 is mechanosensitive: mechanical force modulates several facets of NaV1.5’s voltage-gated function, and some NaV1.5 channelopathies are associated with abnormal NaV1.5 mechanosensitivity (MS). A class of membrane-active drugs, known as amphiphiles, therapeutically target NaV1.5’s voltage-gated function and produce off-target effects including alteration of MS. Amphiphiles may provide a novel option for therapeutic modulation of NaV1.5’s mechanosensitive operation. To more selectively target NaV1.5 MS, we searched for a membrane-partitioning amphipathic agent that would inhibit MS with minimal closed-state inhibition of voltage-gated currents. Among the amphiphiles tested, we selected capsaicin for further study. We used two methods to assess the effects of capsaicin on NaV1.5 MS: (1) membrane suction in cell-attached macroscopic patches and (2) fluid shear stress on whole cells. We tested the effect of capsaicin on NaV1.5 MS by examining macro-patch and whole-cell Na+ current parameters with and without force. Capsaicin abolished the pressure- and shear-mediated peak current increase and acceleration; and the mechanosensitive shifts in the voltage-dependence of activation (shear) and inactivation (pressure and shear). Exploring the recovery from inactivation and use-dependent entry into inactivation, we found divergent stimulus-dependent effects that could potentiate or mitigate the effect of capsaicin, suggesting that mechanical stimuli may differentially modulate NaV1.5 MS. We conclude that selective modulation of NaV1.5 MS makes capsaicin a promising candidate for therapeutic interventions targeting MS.
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Affiliation(s)
- Luke M Cowan
- Division of Gastroenterology and Hepatology, Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, MN, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Mn, USA
| | - Peter R Strege
- Division of Gastroenterology and Hepatology, Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, MN, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Mn, USA
| | - Radda Rusinova
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
| | - Olaf S Andersen
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
| | - Gianrico Farrugia
- Division of Gastroenterology and Hepatology, Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, MN, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Mn, USA
| | - Arthur Beyder
- Division of Gastroenterology and Hepatology, Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, MN, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Mn, USA
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Kumbhare SV, Francis-Lyon PA, Kachru D, Uday T, Irudayanathan C, Muthukumar KM, Ricchetti RR, Singh-Rambiritch S, Ugalde J, Dulai PS, Almonacid DE, Sinha R. Digital Therapeutics Care Utilizing Genetic and Gut Microbiome Signals for the Management of Functional Gastrointestinal Disorders: Results From a Preliminary Retrospective Study. Front Microbiol 2022; 13:826916. [PMID: 35391720 PMCID: PMC8983270 DOI: 10.3389/fmicb.2022.826916] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/28/2022] [Indexed: 12/12/2022] Open
Abstract
Diet and lifestyle-related illnesses including functional gastrointestinal disorders (FGIDs) and obesity are rapidly emerging health issues worldwide. Research has focused on addressing FGIDs via in-person cognitive-behavioral therapies, diet modulation and pharmaceutical intervention. Yet, there is paucity of research reporting on digital therapeutics care delivering weight loss and reduction of FGID symptom severity, and on modeling FGID status and symptom severity reduction including personalized genomic SNPs and gut microbiome signals. Our aim for this study was to assess how effective a digital therapeutics intervention personalized on genomic SNPs and gut microbiome signals was at reducing symptomatology of FGIDs on individuals that successfully lost body weight. We also aimed at modeling FGID status and FGID symptom severity reduction using demographics, genomic SNPs, and gut microbiome variables. This study sought to train a logistic regression model to differentiate the FGID status of subjects enrolled in a digital therapeutics care program using demographic, genetic, and baseline microbiome data. We also trained linear regression models to ascertain changes in FGID symptom severity of subjects at the time of achieving 5% or more of body weight loss compared to baseline. For this we utilized a cohort of 177 adults who reached 5% or more weight loss on the Digbi Health personalized digital care program, who were retrospectively surveyed about changes in symptom severity of their FGIDs and other comorbidities before and after the program. Gut microbiome taxa and demographics were the strongest predictors of FGID status. The digital therapeutics program implemented, reduced the summative severity of symptoms for 89.42% (93/104) of users who reported FGIDs. Reduction in summative FGID symptom severity and IBS symptom severity were best modeled by a mixture of genomic and microbiome predictors, whereas reduction in diarrhea and constipation symptom severity were best modeled by microbiome predictors only. This preliminary retrospective study generated diagnostic models for FGID status as well as therapeutic models for reduction of FGID symptom severity. Moreover, these therapeutic models generate testable hypotheses for associations of a number of biomarkers in the prognosis of FGIDs symptomatology.
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Affiliation(s)
| | - Patricia A. Francis-Lyon
- Digbi Health, Mountain View, CA, United States
- Health Informatics, University of San Francisco, San Francisco, CA, United States
| | - Dashyanng Kachru
- Digbi Health, Mountain View, CA, United States
- Health Informatics, University of San Francisco, San Francisco, CA, United States
| | | | | | | | | | | | - Juan Ugalde
- Universidad del Desarrollo, Facultad de Ingeniería, Centro de Investigación en Tecnologías para la Sociedad (C+), Santiago, Chile
| | - Parambir S. Dulai
- Division of Gastroenterology, University of California, San Diego, San Diego, CA, United States
| | | | - Ranjan Sinha
- Digbi Health, Mountain View, CA, United States
- *Correspondence: Ranjan Sinha,
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Lim XR, Bradley E, Griffin CS, Hollywood MA, Sergeant GP, Thornbury KD. Fast voltage-dependent sodium (Na V ) currents are functionally expressed in mouse corpus cavernosum smooth muscle cells. Br J Pharmacol 2021; 179:1082-1101. [PMID: 34767251 DOI: 10.1111/bph.15728] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 10/17/2021] [Accepted: 10/19/2021] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND AND PURPOSE Corpus cavernosum smooth muscle (CCSM) exhibits phasic contractions that are coordinated by ion channels. Mouse models are commonly used to study erectile dysfunction, but there are few published electrophysiological studies of mouse CCSM. We describe, for the first time, voltage-dependent sodium (NaV ) currents in mouse CCSM and investigate their function. EXPERIMENTAL APPROACH Electrophysiological, pharmacological, and immunocytochemical studies on isolated CCSM cells. Tension measurements in whole tissue. KEY RESULTS A fast, voltage-dependent sodium current was induced by depolarising steps. Steady-state activation and inactivation curves revealed a window current between -60 and -30 mV. Two populations of NaV currents, ('TTX-sensitive') and ('TTX-insensitive'), were distinguished. TTX-sensitive current showed 48% block with the NaV -subtype-specific blockers ICA-121431 (NaV 1.1-1.3), PF-05089771 (NaV 1.7), and 4,9-anhydro-TTX (NaV 1.6). TTX-insensitive current was insensitive to A803467, a NaV 1.8 blocker. Immunocytochemistry confirmed the expression of NaV 1.5 and NaV 1.4 in freshly dispersed CCSM cells. Veratridine, a NaV activator, reduced time-dependent inactivation of the current and increased the duration of evoked action potentials. Veratridine induced phasic contractions in CCSM strips. This effect was reversible with TTX and nifedipine but not by KB-R7943. CONCLUSION AND IMPLICATIONS We report, for the first time, a fast voltage-dependent sodium current in mouse CCSM. Stimulation of this current increases the contractility of corpus cavernosum in vitro, suggesting that it may contribute to the mechanisms of detumescence, and potentially serve as a clinically relevant target for pharmaceutical intervention in erectile dysfunction. Further work will be necessary to define its role.
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Affiliation(s)
| | | | | | | | | | - Keith D Thornbury
- Smooth Muscle Research Centre Dundalk Institute of Technology, Dublin, Ireland
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Huizinga JD, Hussain A, Chen JH. Interstitial cells of Cajal and human colon motility in health and disease. Am J Physiol Gastrointest Liver Physiol 2021; 321:G552-G575. [PMID: 34612070 DOI: 10.1152/ajpgi.00264.2021] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Our understanding of human colonic motility, and autonomic reflexes that generate motor patterns, has increased markedly through high-resolution manometry. Details of the motor patterns are emerging related to frequency and propagation characteristics that allow linkage to interstitial cells of Cajal (ICC) networks. In studies on colonic motor dysfunction requiring surgery, ICC are almost always abnormal or significantly reduced. However, there are still gaps in our knowledge about the role of ICC in the control of colonic motility and there is little understanding of a mechanistic link between ICC abnormalities and colonic motor dysfunction. This review will outline the various ICC networks in the human colon and their proven and likely associations with the enteric and extrinsic autonomic nervous systems. Based on our extensive knowledge of the role of ICC in the control of gastrointestinal motility of animal models and the human stomach and small intestine, we propose how ICC networks are underlying the motor patterns of the human colon. The role of ICC will be reviewed in the autonomic neural reflexes that evoke essential motor patterns for transit and defecation. Mechanisms underlying ICC injury, maintenance, and repair will be discussed. Hypotheses are formulated as to how ICC dysfunction can lead to motor abnormalities in slow transit constipation, chronic idiopathic pseudo-obstruction, Hirschsprung's disease, fecal incontinence, diverticular disease, and inflammatory conditions. Recent studies on ICC repair after injury hold promise for future therapies.
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Affiliation(s)
- Jan D Huizinga
- Division of Gastroenterology, Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Amer Hussain
- Division of Gastroenterology, Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Ji-Hong Chen
- Division of Gastroenterology, Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
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Beck VC, Isom LL, Berg AT. Gastrointestinal Symptoms and Channelopathy-Associated Epilepsy. J Pediatr 2021; 237:41-49.e1. [PMID: 34181986 PMCID: PMC8478841 DOI: 10.1016/j.jpeds.2021.06.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/28/2021] [Accepted: 06/11/2021] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To determine the prevalence of and identify factors associated with gastrointestinal (GI) symptoms among children with channelopathy-associated developmental and epileptic encephalopathy (DEE). STUDY DESIGN Parents of 168 children with DEEs linked to SCN1A (n = 59), KCNB1 (n = 31), or KCNQ2 (n = 78) completed online CLIRINX surveys about their children's GI symptoms. Our analysis examined the prevalence, frequency, and severity of GI symptoms, as well as DEE type, functional mobility, feeding difficulties, ketogenic diet, antiseizure medication, autism spectrum disorder (ASD), and seizures. Statistical analyses included the χ2 test, Wilcoxon rank-sum analysis, and multiple logistic regression. RESULTS GI symptoms were reported in 92 of 168 patients (55%), among whom 63 of 86 (73%) reported daily or weekly symptoms, 29 of 92 (32%) had frequent or serious discomfort, and 13 of 91 (14%) had frequent or serious appetite disturbances as a result. The prevalence of GI symptoms varied across DEE cohorts with 44% of SCN1A-DEE patients, 35% of KCNB1-DEE patients, and 71% of KCNQ2-DEE patients reporting GI symptoms in the previous month. After adjustment for DEE type, current use of ketogenic diet (6% reported), and gastrostomy tube (13% reported) were both associated with GI symptoms in a statistically, but not clinically, significant manner (P < .05). Patient age, functional mobility, feeding difficulties, ASD, and seizures were not clearly associated with GI symptoms. Overall, no individual antiseizure medication was significantly associated with GI symptoms across all DEE cohorts. CONCLUSIONS GI symptoms are common and frequently severe in patients with DEE.
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Affiliation(s)
- Veronica C Beck
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI; Department of Pharmacology, University of Michigan, Ann Arbor, MI
| | - Lori L Isom
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI; Department of Pharmacology, University of Michigan, Ann Arbor, MI; Department of Neurology, University of Michigan, Ann Arbor, MI; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Anne T Berg
- Division of Neurology, Epilepsy Center, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL; Department of Pediatrics, Northwestern Feinberg School of Medicine, Chicago, IL.
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The Relieving Effects of a Polyherb-Based Dietary Supplement ColonVita on Gastrointestinal Quality of Life Index (GIQLI) in Older Adults with Chronic Gastrointestinal Symptoms Are Influenced by Age and Cardiovascular Disease: A 12-Week Randomized Placebo-Controlled Trial. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2021:6653550. [PMID: 34539805 PMCID: PMC8448599 DOI: 10.1155/2021/6653550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 07/16/2021] [Accepted: 08/17/2021] [Indexed: 11/29/2022]
Abstract
Chronic gastrointestinal symptoms (CGS) negatively affect the quality of life in about 15–30% of the population without effective drugs. Recent studies suggest that dietary supplement may improve CGS, but inconsistent results exist. The goal of this study is to evaluate the effect of a polyherbal-based supplement ColonVita on the gastrointestinal quality of life index (GIQLI) in 100 old adults with CGS (63.1 ± 9.6 years) who were randomly assigned to daily ColonVita or placebo tablets (n = 50/group) for 12 weeks in a double-blind, randomized controlled trial design. No significant fibrdifferences were found between ColonVita and placebo in the baseline total GIQLI score (101.12 ± 16.87 vs. 101.80 ± 16.48) (P > 0.05) or postintervention total GIQLI score (114.78 ± 9.62 vs. 111.74 ± 13.01) (P > 0.05). However, ColonVita significantly improved 16 scores of the 19 core GI symptoms compared with 10 items improved by placebo. The ColonVita group significantly improved the remission rate of 5 core GI symptoms compared to placebo and significantly improved the total GIQLI scores (118.09 ± 7.88 vs. 109.50 ± 16.71) (P < 0.05) and core GI symptom scores (64.61 ± 3.99 vs. 60.00 ± 8.65) (P < 0.05) in people ≥60 years of age (n = 49) but not in those under 60 y (n = 51). ColonVita significantly improved the total GIQLI scores and core GI symptom scores in people without cardiovascular diseases (CVD) (n = 56) (116.74 ± 9.38 vs. 110.10 ± 14.28) (P < 0.05) and (63.11 ± 4.53 vs. 59.93 ± 8.03) (P=0.07), respectively, but not in those with CVD (n = 44). Thus, ColonVita was beneficial for old adults with CGS, especially those ≥60 years of age and without CVD. Because a heterogenous pathogenesis of CGS-like irritable bowel syndrome (IBS) and inflammatory bowel disease (ISD) is differentially associated with CVD, different comorbidities may have influenced the outcomes of different trials that should be controlled in further studies.
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10
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Tetrodotoxin: A New Strategy to Treat Visceral Pain? Toxins (Basel) 2021; 13:toxins13070496. [PMID: 34357968 PMCID: PMC8310099 DOI: 10.3390/toxins13070496] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 12/13/2022] Open
Abstract
Visceral pain is one of the most common symptoms associated with functional gastrointestinal (GI) disorders. Although the origin of these symptoms has not been clearly defined, the implication of both the central and peripheral nervous systems in visceral hypersensitivity is well established. The role of several pathways in visceral nociception has been explored, as well as the influence of specific receptors on afferent neurons, such as voltage-gated sodium channels (VGSCs). VGSCs initiate action potentials and dysfunction of these channels has recently been associated with painful GI conditions. Current treatments for visceral pain generally involve opioid based drugs, which are associated with important side-effects and a loss of effectiveness or tolerance. Hence, efforts have been intensified to find new, more effective and longer-lasting therapies. The implication of VGSCs in visceral hypersensitivity has drawn attention to tetrodotoxin (TTX), a relatively selective sodium channel blocker, as a possible and promising molecule to treat visceral pain and related diseases. As such, here we will review the latest information regarding this toxin that is relevant to the treatment of visceral pain and the possible advantages that it may offer relative to other treatments, alone or in combination.
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11
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Sarica AS, Bor S, Orman MN, Barajas-Martinez H, Juang JMJ, Antzelevitch C, Hasdemir C. Frequency of Irritable Bowel Syndrome in Patients with Brugada Syndrome and Drug-Induced Type 1 Brugada Pattern. Am J Cardiol 2021; 151:51-56. [PMID: 34034907 DOI: 10.1016/j.amjcard.2021.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 11/26/2022]
Abstract
Irritable bowel syndrome (IBS) is one of the most widely recognized functional bowel disorders (FBDs) with a genetic component. SCN5A gene and SCN1B loci have been identified in population-based IBS cohorts and proposed to have a mechanistic role in the pathophysiology of IBS. These same genes have been associated with Brugada syndrome (BrS). The present study examines the hypothesis that these two inherited syndromes are linked. Prevalence of FBDs over a 12 months period were compared between probands with BrS/drug-induced type 1 Brugada pattern (DI-Type 1 BrP) (n = 148) and a control group (n = 124) matched for age, female sex, presence of arrhythmia and co-morbid conditions. SCN5A/SCN1B genes were screened in 88 patients. Prevalence of IBS was 25% in patients with BrS/DI-Type 1 BrP and 8.1% in the control group (p = 2.34 × 10-4). On stepwise logistic regression analysis, presence of current and/or history of migraine (OR of 2.75; 95% CI: 1.08 to 6.98; p = 0.033) was a predictor of underlying BrS/DI-Type 1 BrP among patients with FBDs. We identified 8 putative SCN5A/SCN1B variants in 7 (12.3%) patients with BrS/DI-Type 1 BrP and 1 (3.2%) patient in control group. Five out of 8 (62.5%) patients with SCN5A/SCN1B variants had FBDs. In conclusion, IBS is a common co-morbidity in patients with BrS/DI-Type 1 BrP. Presence of current and/or history of migraine are a predictor of underlying BrS/DI-Type 1 BrP among patients with FBDs. Frequent co-existence of IBS and BrS/DI-Type 1 BrP necessitates cautious use of certain drugs among the therapeutic options for IBS that are known to exacerbate the Brugada phenotype.
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12
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Fukudo S, Okumura T, Inamori M, Okuyama Y, Kanazawa M, Kamiya T, Sato K, Shiotani A, Naito Y, Fujikawa Y, Hokari R, Masaoka T, Fujimoto K, Kaneko H, Torii A, Matsueda K, Miwa H, Enomoto N, Shimosegawa T, Koike K. Evidence-based clinical practice guidelines for irritable bowel syndrome 2020. J Gastroenterol 2021; 56:193-217. [PMID: 33538894 PMCID: PMC7932982 DOI: 10.1007/s00535-020-01746-z] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 10/27/2020] [Indexed: 02/06/2023]
Abstract
Managing irritable bowel syndrome (IBS) has attracted international attention because single-agent therapy rarely relieves bothersome symptoms for all patients. The Japanese Society of Gastroenterology (JSGE) published the first edition of evidence-based clinical practice guidelines for IBS in 2015. Much more evidence has accumulated since then, and new pharmacological agents and non-pharmacological methods have been developed. Here, we report the second edition of the JSGE-IBS guidelines comprising 41 questions including 12 background questions on epidemiology, pathophysiology, and diagnostic criteria, 26 clinical questions on diagnosis and treatment, and 3 questions on future research. For each question, statements with or without recommendations and/or evidence level are given and updated diagnostic and therapeutic algorithms are provided based on new evidence. Algorithms for diagnosis are requisite for patients with chronic abdominal pain or associated symptoms and/or abnormal bowel movement. Colonoscopy is indicated for patients with one or more alarm symptoms/signs, risk factors, and/or abnormal routine examination results. The diagnosis is based on the Rome IV criteria. Step 1 therapy consists of diet therapy, behavioral modification, and gut-targeted pharmacotherapy for 4 weeks. For non-responders, management proceeds to step 2 therapy, which includes a combination of different mechanistic gut-targeted agents and/or psychopharmacological agents and basic psychotherapy for 4 weeks. Step 3 therapy is for non-responders to step 2 and comprises a combination of gut-targeted pharmacotherapy, psychopharmacological treatments, and/or specific psychotherapy. These updated JSGE-IBS guidelines present best practice strategies for IBS patients in Japan and we believe these core strategies can be useful for IBS diagnosis and treatment globally.
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Affiliation(s)
- Shin Fukudo
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan.
- Department of Behavioral Medicine Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
| | - Toshikatsu Okumura
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Masahiko Inamori
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Yusuke Okuyama
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Motoyori Kanazawa
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Takeshi Kamiya
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Ken Sato
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Akiko Shiotani
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Yuji Naito
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Yoshiko Fujikawa
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Ryota Hokari
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Tastuhiro Masaoka
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Kazuma Fujimoto
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Hiroshi Kaneko
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Akira Torii
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Kei Matsueda
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Hiroto Miwa
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Nobuyuki Enomoto
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Tooru Shimosegawa
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
| | - Kazuhiko Koike
- Guidelines Committee for Creating and Evaluating the "Evidence-Based Clinical Practice Guidelines for Irritable Bowel Syndrome", The Japanese Society of Gastroenterology, 6F Shimbashi i-MARK Building, 2-6-2 Shimbashi, Minato-ku, Tokyo, 105-0004, Japan
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13
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Nathan S, Gabelli SB, Yoder JB, Srinivasan L, Aldrich RW, Tomaselli GF, Ben-Johny M, Amzel LM. Structural basis of cytoplasmic NaV1.5 and NaV1.4 regulation. J Gen Physiol 2020; 153:211587. [PMID: 33306788 PMCID: PMC7953540 DOI: 10.1085/jgp.202012722] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/06/2020] [Indexed: 12/14/2022] Open
Abstract
Voltage-gated sodium channels (NaVs) are membrane proteins responsible for the rapid upstroke of the action potential in excitable cells. There are nine human voltage-sensitive NaV1 isoforms that, in addition to their sequence differences, differ in tissue distribution and specific function. This review focuses on isoforms NaV1.4 and NaV1.5, which are primarily expressed in skeletal and cardiac muscle cells, respectively. The determination of the structures of several eukaryotic NaVs by single-particle cryo-electron microscopy (cryo-EM) has brought new perspective to the study of the channels. Alignment of the cryo-EM structure of the transmembrane channel pore with x-ray crystallographic structures of the cytoplasmic domains illustrates the complementary nature of the techniques and highlights the intricate cellular mechanisms that modulate these channels. Here, we review structural insights into the cytoplasmic C-terminal regulation of NaV1.4 and NaV1.5 with special attention to Ca2+ sensing by calmodulin, implications for disease, and putative channel dimerization.
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Affiliation(s)
- Sara Nathan
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Sandra B Gabelli
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD.,Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Jesse B Yoder
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Lakshmi Srinivasan
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Richard W Aldrich
- Department of Neuroscience, University of Texas at Austin, Austin, TX
| | - Gordon F Tomaselli
- Division of Cardiology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY
| | - L Mario Amzel
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD.,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD
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14
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Mah SA, Avci R, Cheng LK, Du P. Current applications of mathematical models of the interstitial cells of Cajal in the gastrointestinal tract. WIREs Mech Dis 2020; 13:e1507. [PMID: 33026190 DOI: 10.1002/wsbm.1507] [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: 06/12/2020] [Revised: 08/31/2020] [Accepted: 09/04/2020] [Indexed: 12/25/2022]
Abstract
The interstitial cells of Cajal (ICC) form interconnected networks throughout the gastrointestinal (GI) tract. ICC act as the pacemaker cells that initiate the rhythmic bioelectrical slow waves and intermediary between the GI musculature and nerves, both of which are critical to GI motility. Disruptions to the number of ICC and the integrity of ICC networks have been identified as a key pathophysiological mechanism in a number of clinically challenging GI disorders. The current analyses of ICC generally rely on either functional recordings taken directly from excised tissue or morphological analysis based on images of labeled ICC, where the structural-functional relationship is investigated in an associative manner rather than mechanistically. On the other hand, computational physiology has played a significant role in facilitating our understanding of a number of physiological systems in both health and disease, and investigations in the GI field are beginning to incorporate several mathematical models of the ICC. The main aim of this review is to present the major modeling advances in GI electrophysiology, in order to introduce a multi-scale framework for mathematically quantifying the functional consequences of ICC degradation at both cellular and tissue scales. The outcomes will inform future investigators utilizing modeling techniques in their studies. This article is categorized under: Metabolic Diseases > Computational Models.
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Affiliation(s)
- Sue Ann Mah
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Department of Engineering Science, University of Auckland, Auckland, New Zealand
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15
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Xiao QY, Fang XC, Li XQ, Fei GJ. Ethnic differences in genetic polymorphism associated with irritable bowel syndrome. World J Gastroenterol 2020; 26:2049-2063. [PMID: 32536774 PMCID: PMC7267697 DOI: 10.3748/wjg.v26.i17.2049] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/25/2020] [Accepted: 04/04/2020] [Indexed: 02/06/2023] Open
Abstract
Genetic polymorphism is associated with irritable bowel syndrome (IBS) in terms of susceptibility and clinical manifestations. Previous studies have shown that genetic polymorphism might play a key role in the onset and progression of IBS by modulating components of its pathogenesis such as the gut-brain axis, gastrointestinal motility, inflammatory activity, and immune status. Although underlying pathophysiological mechanisms have not been fully clarified, the potential ethnic differences that are present in worldwide genetic studies of IBS deserve attention. This review surveyed numerous studies focusing on IBS-associated single nucleotide polymorphisms, and investigated the ethnic disparities revealed by them. The results demonstrate the need for more attention on ethnic factors in IBS-related genetic studies. Taking ethnic backgrounds into accounts and placing emphasis on disparities potentially ascribed to ethnicity could help lay a solid and generalized foundation for transcultural, multi-ethnic, or secondary analyses in IBS, for example, a meta-analysis. Broader genetic studies considering ethnic factors are greatly needed to obtain a better understanding of the pathophysiological mechanisms of IBS and to improve the prevention, intervention, and treatment of this disease.
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Affiliation(s)
- Qi-Yun Xiao
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Xiu-Cai Fang
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Xiao-Qing Li
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Gui-Jun Fei
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
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16
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Mazzone A, Strege PR, Gibbons SJ, Alcaino C, Joshi V, Haak AJ, Tschumperlin DJ, Bernard CE, Cima RR, Larson DW, Chua HK, Graham RP, El Refaey M, Mohler PJ, Hayashi Y, Ordog T, Calder S, Du P, Farrugia G, Beyder A. microRNA overexpression in slow transit constipation leads to reduced Na V1.5 current and altered smooth muscle contractility. Gut 2020; 69:868-876. [PMID: 31757880 PMCID: PMC7147984 DOI: 10.1136/gutjnl-2019-318747] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 10/16/2019] [Accepted: 11/06/2019] [Indexed: 12/13/2022]
Abstract
OBJECTIVE This study was designed to evaluate the roles of microRNAs (miRNAs) in slow transit constipation (STC). DESIGN All human tissue samples were from the muscularis externa of the colon. Expression of 372 miRNAs was examined in a discovery cohort of four patients with STC versus three age/sex-matched controls by a quantitative PCR array. Upregulated miRNAs were examined by quantitative reverse transcription qPCR (RT-qPCR) in a validation cohort of seven patients with STC and age/sex-matched controls. The effect of a highly differentially expressed miRNA on a custom human smooth muscle cell line was examined in vitro by RT-qPCR, electrophysiology, traction force microscopy, and ex vivo by lentiviral transduction in rat muscularis externa organotypic cultures. RESULTS The expression of 13 miRNAs was increased in STC samples. Of those miRNAs, four were predicted to target SCN5A, the gene that encodes the Na+ channel NaV1.5. The expression of SCN5A mRNA was decreased in STC samples. Let-7f significantly decreased Na+ current density in vitro in human smooth muscle cells. In rat muscularis externa organotypic cultures, overexpression of let-7f resulted in reduced frequency and amplitude of contraction. CONCLUSIONS A small group of miRNAs is upregulated in STC, and many of these miRNAs target the SCN5A-encoded Na+ channel NaV1.5. Within this set, a novel NaV1.5 regulator, let-7f, resulted in decreased NaV1.5 expression, current density and reduced motility of GI smooth muscle. These results suggest NaV1.5 and miRNAs as novel diagnostic and potential therapeutic targets in STC.
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Affiliation(s)
- Amelia Mazzone
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Peter R Strege
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Simon J Gibbons
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Constanza Alcaino
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Vikram Joshi
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Andrew J Haak
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Daniel J Tschumperlin
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Cheryl E Bernard
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Robert R Cima
- Department of Colon and Rectal Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - David W Larson
- Department of Colon and Rectal Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Heidi K Chua
- Department of Colon and Rectal Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Mona El Refaey
- Departments of Physiology and Cell Biology, The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA,Department of Internal Medicine, The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Peter J Mohler
- Departments of Physiology and Cell Biology, The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Yujiro Hayashi
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Tamas Ordog
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Stefan Calder
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Gianrico Farrugia
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA .,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Arthur Beyder
- Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA .,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
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17
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Strege PR, Mercado-Perez A, Mazzone A, Saito YA, Bernard CE, Farrugia G, Beyder A. SCN5A mutation G615E results in Na V1.5 voltage-gated sodium channels with normal voltage-dependent function yet loss of mechanosensitivity. Channels (Austin) 2019; 13:287-298. [PMID: 31262209 PMCID: PMC6629189 DOI: 10.1080/19336950.2019.1632670] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 06/06/2019] [Accepted: 06/10/2019] [Indexed: 12/19/2022] Open
Abstract
SCN5A is expressed in cardiomyocytes and gastrointestinal (GI) smooth muscle cells (SMCs) as the voltage-gated mechanosensitive sodium channel NaV1.5. The influx of Na+ through NaV1.5 produces a fast depolarization in membrane potential, indispensable for electrical excitability in cardiomyocytes and important for electrical slow waves in GI smooth muscle. As such, abnormal NaV1.5 voltage gating or mechanosensitivity may result in channelopathies. SCN5A mutation G615E - found separately in cases of acquired long-QT syndrome, sudden cardiac death, and irritable bowel syndrome - has a relatively minor effect on NaV1.5 voltage gating. The aim of this study was to test whether G615E impacts mechanosensitivity. Mechanosensitivity of wild-type (WT) or G615E-NaV1.5 in HEK-293 cells was examined by shear stress on voltage- or current-clamped whole cells or pressure on macroscopic patches. Unlike WT, voltage-clamped G615E-NaV1.5 showed a loss in shear- and pressure-sensitivity of peak current yet a normal leftward shift in the voltage-dependence of activation. In current-clamp, shear stress led to a significant increase in firing spike frequency with a decrease in firing threshold for WT but not G615E-NaV1.5. Our results show that the G615E mutation leads to functionally abnormal NaV1.5 channels, which cause disruptions in mechanosensitivity and mechano-electrical feedback and suggest a potential contribution to smooth muscle pathophysiology.
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Affiliation(s)
- Peter R. Strege
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - Arnaldo Mercado-Perez
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
- Medical Scientist Training Program (MSTP), Mayo Clinic, Rochester, MN, USA
| | - Amelia Mazzone
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - Yuri A. Saito
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - Cheryl E. Bernard
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - Gianrico Farrugia
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Arthur Beyder
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
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18
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Maroni M, Körner J, Schüttler J, Winner B, Lampert A, Eberhardt E. β1 and β3 subunits amplify mechanosensitivity of the cardiac voltage-gated sodium channel Nav1.5. Pflugers Arch 2019; 471:1481-1492. [PMID: 31728700 DOI: 10.1007/s00424-019-02324-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 09/25/2019] [Accepted: 10/21/2019] [Indexed: 12/19/2022]
Abstract
In cardiomyocytes, electrical activity is coupled to cellular contraction, thus exposing all proteins expressed in the sarcolemma to mechanical stress. The voltage-gated sodium channel Nav1.5 is the main contributor to the rising phase of the action potential in the heart. There is growing evidence that gating and kinetics of Nav1.5 are modulated by mechanical forces and pathogenic variants that affect mechanosensitivity have been linked to arrhythmias. Recently, the sodium channel β1 subunit has been described to stabilise gating against mechanical stress of Nav1.7 expressed in neurons. Here, we tested the effect of β1 and β3 subunits on mechanosensitivity of the cardiac Nav1.5. β1 amplifies stress-induced shifts of V1/2 of steady-state fast inactivation to hyperpolarised potentials (ΔV1/2: 6.2 mV without and 10.7 mV with β1 co-expression). β3, on the other hand, almost doubles stress-induced speeding of time to sodium current transient peak (Δtime to peak at - 30 mV: 0.19 ms without and 0.37 ms with β3 co-expression). Our findings may indicate that in cardiomyocytes, the interdependence of electrical activity and contraction is used as a means of fine tuning cardiac sodium channel function, allowing quicker but more strongly inactivating sodium currents under conditions of increased mechanical stress. This regulation may help to shorten action potential duration during tachycardia, to prevent re-entry phenomena and thus arrhythmias.
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Affiliation(s)
- Michele Maroni
- Department of Anaesthesiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054, Erlangen, Germany.,Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054, Erlangen, Germany
| | - Jannis Körner
- Institute of Physiology, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany.,Department of Anaesthesiology, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany
| | - Jürgen Schüttler
- Department of Anaesthesiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054, Erlangen, Germany
| | - Beate Winner
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054, Erlangen, Germany
| | - Angelika Lampert
- Institute of Physiology, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany
| | - Esther Eberhardt
- Department of Anaesthesiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054, Erlangen, Germany.
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19
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Piché J, Van Vliet PP, Pucéat M, Andelfinger G. The expanding phenotypes of cohesinopathies: one ring to rule them all! Cell Cycle 2019; 18:2828-2848. [PMID: 31516082 PMCID: PMC6791706 DOI: 10.1080/15384101.2019.1658476] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/13/2019] [Accepted: 08/17/2019] [Indexed: 12/13/2022] Open
Abstract
Preservation and development of life depend on the adequate segregation of sister chromatids during mitosis and meiosis. This process is ensured by the cohesin multi-subunit complex. Mutations in this complex have been associated with an increasing number of diseases, termed cohesinopathies. The best characterized cohesinopathy is Cornelia de Lange syndrome (CdLS), in which intellectual and growth retardations are the main phenotypic manifestations. Despite some overlap, the clinical manifestations of cohesinopathies vary considerably. Novel roles of the cohesin complex have emerged during the past decades, suggesting that important cell cycle regulators exert important biological effects through non-cohesion-related functions and broadening the potential pathomechanisms involved in cohesinopathies. This review focuses on non-cohesion-related functions of the cohesin complex, gene dosage effect, epigenetic regulation and TGF-β in cohesinopathy context, especially in comparison to Chronic Atrial and Intestinal Dysrhythmia (CAID) syndrome, a very distinct cohesinopathy caused by a homozygous Shugoshin-1 (SGO1) mutation (K23E) and characterized by pacemaker failure in both heart (sick sinus syndrome followed by atrial flutter) and gut (chronic intestinal pseudo-obstruction) with no intellectual or growth delay. We discuss the possible impact of SGO1 alterations in human pathologies and the potential impact of the SGO1 K23E mutation in the sinus node and gut development and functions. We suggest that the human phenotypes observed in CdLS, CAID syndrome and other cohesinopathies can inform future studies into the less well-known non-cohesion-related functions of cohesin complex genes. Abbreviations: AD: Alzheimer Disease; AFF4: AF4/FMR2 Family Member 4; ANKRD11: Ankyrin Repeat Domain 11; APC: Anaphase Promoter Complex; ASD: Atrial Septal Defect; ATRX: ATRX Chromatin Remodeler; ATRX: Alpha Thalassemia X-linked intellectual disability syndrome; BIRC5: Baculoviral IAP Repeat Containing 5; BMP: Bone Morphogenetic Protein; BRD4: Bromodomain Containing 4; BUB1: BUB1 Mitotic Checkpoint Serine/Threonine Kinase; CAID: Chronic Atrial and Intestinal Dysrhythmia; CDK1: Cyclin Dependent Kinase 1; CdLS: Cornelia de Lange Syndrome; CHD: Congenital Heart Disease; CHOPS: Cognitive impairment, coarse facies, Heart defects, Obesity, Pulmonary involvement, Short stature, and skeletal dysplasia; CIPO: Chronic Intestinal Pseudo-Obstruction; c-kit: KIT Proto-Oncogene Receptor Tyrosine Kinase; CoATs: Cohesin Acetyltransferases; CTCF: CCCTC-Binding Factor; DDX11: DEAD/H-Box Helicase 11; ERG: Transcriptional Regulator ERG; ESCO2: Establishment of Sister Chromatid Cohesion N-Acetyltransferase 2; GJC1: Gap Junction Protein Gamma 1; H2A: Histone H2A; H3K4: Histone H3 Lysine 4; H3K9: Histone H3 Lysine 9; HCN4: Hyperpolarization Activated Cyclic Nucleotide Gated Potassium and Sodium Channel 4;p HDAC8: Histone deacetylases 8; HP1: Heterochromatin Protein 1; ICC: Interstitial Cells of Cajal; ICC-MP: Myenteric Plexus Interstitial cells of Cajal; ICC-DMP: Deep Muscular Plexus Interstitial cells of Cajal; If: Pacemaker Funny Current; IP3: Inositol trisphosphate; JNK: C-Jun N-Terminal Kinase; LDS: Loeys-Dietz Syndrome; LOAD: Late-Onset Alzheimer Disease; MAPK: Mitogen-Activated Protein Kinase; MAU: MAU Sister Chromatid Cohesion Factor; MFS: Marfan Syndrome; NIPBL: NIPBL, Cohesin Loading Factor; OCT4: Octamer-Binding Protein 4; P38: P38 MAP Kinase; PDA: Patent Ductus Arteriosus; PDS5: PDS5 Cohesin Associated Factor; P-H3: Phospho Histone H3; PLK1: Polo Like Kinase 1; POPDC1: Popeye Domain Containing 1; POPDC2: Popeye Domain Containing 2; PP2A: Protein Phosphatase 2; RAD21: RAD21 Cohesin Complex Component; RBS: Roberts Syndrome; REC8: REC8 Meiotic Recombination Protein; RNAP2: RNA polymerase II; SAN: Sinoatrial node; SCN5A: Sodium Voltage-Gated Channel Alpha Subunit 5; SEC: Super Elongation Complex; SGO1: Shogoshin-1; SMAD: SMAD Family Member; SMC1A: Structural Maintenance of Chromosomes 1A; SMC3: Structural Maintenance of Chromosomes 3; SNV: Single Nucleotide Variant; SOX2: SRY-Box 2; SOX17: SRY-Box 17; SSS: Sick Sinus Syndrome; STAG2: Cohesin Subunit SA-2; TADs: Topology Associated Domains; TBX: T-box transcription factors; TGF-β: Transforming Growth Factor β; TGFBR: Transforming Growth Factor β receptor; TOF: Tetralogy of Fallot; TREK1: TREK-1 K(+) Channel Subunit; VSD: Ventricular Septal Defect; WABS: Warsaw Breakage Syndrome; WAPL: WAPL Cohesin Release Factor.
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Affiliation(s)
- Jessica Piché
- Cardiovascular Genetics, Department of Pediatrics, CHU Sainte-Justine, Montréal, QC, Canada
| | - Patrick Piet Van Vliet
- Cardiovascular Genetics, Department of Pediatrics, CHU Sainte-Justine, Montréal, QC, Canada
- LIA (International Associated Laboratory), CHU Sainte-Justine, Montréal, QC, Canada
- LIA (International Associated Laboratory), INSERM, Marseille, U1251-13885, France
| | - Michel Pucéat
- LIA (International Associated Laboratory), CHU Sainte-Justine, Montréal, QC, Canada
- LIA (International Associated Laboratory), INSERM, Marseille, U1251-13885, France
- INSERM U-1251, MMG,Aix-Marseille University, Marseille, 13885, France
| | - Gregor Andelfinger
- Cardiovascular Genetics, Department of Pediatrics, CHU Sainte-Justine, Montréal, QC, Canada
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Burns G, Pryor J, Holtmann G, Walker MM, Talley NJ, Keely S. Immune Activation in Functional Gastrointestinal Disorders. Gastroenterol Hepatol (N Y) 2019; 15:539-548. [PMID: 31802978 PMCID: PMC6883739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
There is growing appreciation that functional gastrointestinal disorders (FGIDs) such as functional dyspepsia and irritable bowel syndrome are heterogeneous conditions linked by subtle inflammation within the gastrointestinal (GI) tract. The literature suggests that while the symptoms of these diseases may manifest with similar clinical presentations, there are significant differences in triggers and disease severity among patients classified into the same subtype. It is hypothesized that the subtle inflammation observed in these patients is related to an imbalance in GI homeostasis. Disruption of the delicate homeostatic balance within the GI tract can result from any number or combination of factors, including dysbiosis, loss of barrier integrity, genetic predisposition, or immune responses to dietary or luminal antigens. This article discusses the interplay between the immune system, microbiota, and luminal environment in FGIDs. In addition, the article proposes emerging immune pathways, including those involving T-helper type 17 response and innate lymphoid cells, as potential regulators of the subtle inflammation characteristic of FGIDs that warrant investigation in future studies.
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Affiliation(s)
- Grace Burns
- Ms Burns is a PhD graduate student, Ms Pryor is an undergraduate research student
- Dr Walker is a professor of anatomical pathology
- Dr Talley is a laureate professor
- Dr Keely is an associate professor in the Priority Research Centre for Digestive Health and Neurogastroenterology in the Faculty of Health and Medicine at the University of Newcastle in Callaghan, New South Wales, Australia, as well as in the Hunter Medical Research Institute in New Lambton Heights, New South Wales, Australia
- Dr Holtmann is director of gastroenterology and hepatology at the Princess Alexandra Hospital in Brisbane, Queensland, Australia and a professor in the Faculty of Medicine at the University of Queensland in Woolloongabba, Queensland, Australia
| | - Jennifer Pryor
- Ms Burns is a PhD graduate student, Ms Pryor is an undergraduate research student
- Dr Walker is a professor of anatomical pathology
- Dr Talley is a laureate professor
- Dr Keely is an associate professor in the Priority Research Centre for Digestive Health and Neurogastroenterology in the Faculty of Health and Medicine at the University of Newcastle in Callaghan, New South Wales, Australia, as well as in the Hunter Medical Research Institute in New Lambton Heights, New South Wales, Australia
- Dr Holtmann is director of gastroenterology and hepatology at the Princess Alexandra Hospital in Brisbane, Queensland, Australia and a professor in the Faculty of Medicine at the University of Queensland in Woolloongabba, Queensland, Australia
| | - Gerald Holtmann
- Ms Burns is a PhD graduate student, Ms Pryor is an undergraduate research student
- Dr Walker is a professor of anatomical pathology
- Dr Talley is a laureate professor
- Dr Keely is an associate professor in the Priority Research Centre for Digestive Health and Neurogastroenterology in the Faculty of Health and Medicine at the University of Newcastle in Callaghan, New South Wales, Australia, as well as in the Hunter Medical Research Institute in New Lambton Heights, New South Wales, Australia
- Dr Holtmann is director of gastroenterology and hepatology at the Princess Alexandra Hospital in Brisbane, Queensland, Australia and a professor in the Faculty of Medicine at the University of Queensland in Woolloongabba, Queensland, Australia
| | - Marjorie M Walker
- Ms Burns is a PhD graduate student, Ms Pryor is an undergraduate research student
- Dr Walker is a professor of anatomical pathology
- Dr Talley is a laureate professor
- Dr Keely is an associate professor in the Priority Research Centre for Digestive Health and Neurogastroenterology in the Faculty of Health and Medicine at the University of Newcastle in Callaghan, New South Wales, Australia, as well as in the Hunter Medical Research Institute in New Lambton Heights, New South Wales, Australia
- Dr Holtmann is director of gastroenterology and hepatology at the Princess Alexandra Hospital in Brisbane, Queensland, Australia and a professor in the Faculty of Medicine at the University of Queensland in Woolloongabba, Queensland, Australia
| | - Nicholas J Talley
- Ms Burns is a PhD graduate student, Ms Pryor is an undergraduate research student
- Dr Walker is a professor of anatomical pathology
- Dr Talley is a laureate professor
- Dr Keely is an associate professor in the Priority Research Centre for Digestive Health and Neurogastroenterology in the Faculty of Health and Medicine at the University of Newcastle in Callaghan, New South Wales, Australia, as well as in the Hunter Medical Research Institute in New Lambton Heights, New South Wales, Australia
- Dr Holtmann is director of gastroenterology and hepatology at the Princess Alexandra Hospital in Brisbane, Queensland, Australia and a professor in the Faculty of Medicine at the University of Queensland in Woolloongabba, Queensland, Australia
| | - Simon Keely
- Ms Burns is a PhD graduate student, Ms Pryor is an undergraduate research student
- Dr Walker is a professor of anatomical pathology
- Dr Talley is a laureate professor
- Dr Keely is an associate professor in the Priority Research Centre for Digestive Health and Neurogastroenterology in the Faculty of Health and Medicine at the University of Newcastle in Callaghan, New South Wales, Australia, as well as in the Hunter Medical Research Institute in New Lambton Heights, New South Wales, Australia
- Dr Holtmann is director of gastroenterology and hepatology at the Princess Alexandra Hospital in Brisbane, Queensland, Australia and a professor in the Faculty of Medicine at the University of Queensland in Woolloongabba, Queensland, Australia
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Exploration of Ion Channels in the Clitoris: a Review. CURRENT SEXUAL HEALTH REPORTS 2019. [DOI: 10.1007/s11930-019-00206-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Coates MD, Vrana KE, Ruiz-Velasco V. The influence of voltage-gated sodium channels on human gastrointestinal nociception. Neurogastroenterol Motil 2019; 31:e13460. [PMID: 30216585 DOI: 10.1111/nmo.13460] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 08/01/2018] [Accepted: 08/07/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND Abdominal pain is a frequent and persistent problem in the most common gastrointestinal disorders, including irritable bowel syndrome and inflammatory bowel disease. Pain adversely impacts quality of life, incurs significant healthcare expenditures, and remains a challenging issue to manage with few safe therapeutic options currently available. It is imperative that new methods are developed for identifying and treating this symptom. A variety of peripherally active neuroendocrine signaling elements have the capability to influence gastrointestinal pain perception. A large and growing body of evidence suggests that voltage-gated sodium channels (VGSCs) play a critical role in the development and modulation of nociceptive signaling associated with the gut. Several VGSC isoforms demonstrate significant promise as potential targets for improved diagnosis and treatment of gut-based disorders associated with hyper- and hyposensitivity to abdominal pain. PURPOSE In this article, we critically review key investigations that have evaluated the potential role that VGSCs play in visceral nociception and discuss recent advances related to this topic. Specifically, we discuss the following: (a) what is known about the structure and basic function of VGSCs, (b) the role that each VGSC plays in gut nociception, particularly as it relates to human physiology, and (c) potential diagnostic and therapeutic uses of VGSCs to manage disorders associated with chronic abdominal pain.
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Affiliation(s)
- Matthew D Coates
- Division of Gastroenterology & Hepatology, Department of Medicine, Penn State University College of Medicine, Hershey, Pennsylvania
| | - Kent E Vrana
- Department of Pharmacology, Penn State University College of Medicine, Hershey, Pennsylvania
| | - Victor Ruiz-Velasco
- Department of Anesthesiology and Perioperative Medicine, Penn State University College of Medicine, Hershey, Pennsylvania
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Abstract
The complexity of the human sense of smell is increasingly reflected in complex and high-dimensional data, which opens opportunities for data-driven approaches that complement hypothesis-driven research. Contemporary developments in computational and data science, with its currently most popular implementation as machine learning, facilitate complex data-driven research approaches. The use of machine learning in human olfactory research included major approaches comprising 1) the study of the physiology of pattern-based odor detection and recognition processes, 2) pattern recognition in olfactory phenotypes, 3) the development of complex disease biomarkers including olfactory features, 4) odor prediction from physico-chemical properties of volatile molecules, and 5) knowledge discovery in publicly available big databases. A limited set of unsupervised and supervised machine-learned methods has been used in these projects, however, the increasing use of contemporary methods of computational science is reflected in a growing number of reports employing machine learning for human olfactory research. This review provides key concepts of machine learning and summarizes current applications on human olfactory data.
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Affiliation(s)
- Jörn Lötsch
- Institute of Clinical Pharmacology, Goethe-University, Frankfurt am Main, Germany
- Fraunhofer Institute of Molecular Biology and Applied Ecology - Project Group Translational Medicine and Pharmacology (IME-TMP), Frankfurt am Main, Germany
| | - Dario Kringel
- Institute of Clinical Pharmacology, Goethe-University, Frankfurt am Main, Germany
| | - Thomas Hummel
- Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
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Gonzalez-Lopez E, Imamura Kawasawa Y, Walter V, Zhang L, Koltun WA, Huang X, Vrana KE, Coates MD. Homozygosity for the SCN10A Polymorphism rs6795970 Is Associated With Hypoalgesic Inflammatory Bowel Disease Phenotype. Front Med (Lausanne) 2018; 5:324. [PMID: 30538988 PMCID: PMC6277464 DOI: 10.3389/fmed.2018.00324] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/05/2018] [Indexed: 12/11/2022] Open
Abstract
Background: Hypoalgesic inflammatory bowel disease (IBD), a condition in which patients with active disease do not perceive and/or report abdominal pain, is associated with serious complications and there is a lack of cost-effective, reliable diagnostic methods to identify “at-risk” patients. The voltage-gated sodium channels (VGSC's), Nav1.7, Nav1.8, and Nav1.9, are preferentially expressed on nociceptive neurons, and have been implicated in visceral inflammatory pain. At least 29 VGSC single nucleotide polymorphisms (SNPs) have been implicated in chronic somatic pain syndromes, but little is known about their role in human visceral sensation. We hypothesized that disruptive VGSC polymorphisms result in anti-nociceptive behavior in IBD. Methods and Findings: We performed targeted exome sequencing and/or TaqMan genotyping to evaluate the Nav1.7, Nav1.8, and Nav1.9 genes (SCN9A, SCN10A and SCN11A) in 121 IBD patients (including 41 “hypoalgesic” IBD patients) and 86 healthy controls. Allelic and genotypic frequencies of polymorphisms were compared among study groups who had undergone characterization of intestinal inflammatory status and abdominal pain experience. Forty-nine total exonic SNPs were identified. The allelic frequency of only one non-synonymous SNP (rs6795970 [SCN10A]) approached significance in hypoalgesic IBD patients when compared to other IBD patients (p = 0.096, Fisher's exact test). Hypoalgesic IBD patients were more likely to be homozygous for this polymorphism (46 vs. 22%, p = 0.01, Fisher's exact test). Conclusions: This is the first human study to demonstrate a link between a genetic variant of SCN10A and abdominal pain perception in IBD. These findings provide key insights into visceral nociceptive physiology and new diagnostic and therapeutic targets to consider in IBD and other gastrointestinal conditions associated with chronic abdominal pain. Further studies are required to elucidate the precise pathophysiological impact of the rs6795970 polymorphism on human gastrointestinal nociception.
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Affiliation(s)
- Eugene Gonzalez-Lopez
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, United States
| | - Yuka Imamura Kawasawa
- Departments of Pharmacology and Biochemistry & Molecular Biology, Institute for Personalized Medicine, Penn State College of Medicine, Hershey, PA, United States
| | - Vonn Walter
- Department of Public Health Sciences, Penn State College of Medicine, Hershey, PA, United States
| | - Lijun Zhang
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA, United States
| | - Walter A Koltun
- Division of Colorectal Surgery, Department of Surgery, Penn State College of Medicine, Hershey, PA, United States
| | - Xuemei Huang
- Department of Neurology, Penn State College of Medicine, Hershey, PA, United States
| | - Kent E Vrana
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, United States
| | - Matthew D Coates
- Division of Gastroenterology & Hepatology, Department of Medicine, Penn State College of Medicine, Hershey, PA, United States
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Li W, Yin L, Shen C, Hu K, Ge J, Sun A. SCN5A Variants: Association With Cardiac Disorders. Front Physiol 2018; 9:1372. [PMID: 30364184 PMCID: PMC6191725 DOI: 10.3389/fphys.2018.01372] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 09/10/2018] [Indexed: 12/19/2022] Open
Abstract
The SCN5A gene encodes the alpha subunit of the main cardiac sodium channel Nav1.5. This channel predominates inward sodium current (INa) and plays a critical role in regulation of cardiac electrophysiological function. Since 1995, SCN5A variants have been found to be causatively associated with Brugada syndrome, long QT syndrome, cardiac conduction system dysfunction, dilated cardiomyopathy, etc. Previous genetic, electrophysiological, and molecular studies have identified the arrhythmic and cardiac structural characteristics induced by SCN5A variants. However, due to the variation of disease manifestations and genetic background, impact of environmental factors, as well as the presence of mixed phenotypes, the detailed and individualized physiological mechanisms in various SCN5A-related syndromes are not fully elucidated. This review summarizes the current knowledge of SCN5A genetic variations in different SCN5A-related cardiac disorders and the newly developed therapy strategies potentially useful to prevent and treat these disorders in clinical setting.
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Affiliation(s)
- Wenjia Li
- Department of Cardiology, Shanghai Institute of Cardiovascular Disease, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Lei Yin
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, China
| | - Cheng Shen
- Department of Cardiology, The Affiliated Hospital of Jining Medical University, Jining, China
| | - Kai Hu
- Department of Cardiology, Shanghai Institute of Cardiovascular Disease, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Junbo Ge
- Department of Cardiology, Shanghai Institute of Cardiovascular Disease, Zhongshan Hospital, Fudan University, Shanghai, China.,Department of Cardiology, Institute of Biomedical Science, Fudan University, Shanghai, China
| | - Aijun Sun
- Department of Cardiology, Shanghai Institute of Cardiovascular Disease, Zhongshan Hospital, Fudan University, Shanghai, China.,Department of Cardiology, Institute of Biomedical Science, Fudan University, Shanghai, China
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26
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Jia M, Lu X, Wang Z, Zhao L, Zhang S. Effects of Fengliao-Changweikang in Diarrhea-predominant Irritable Bowel Syndrome Rats and Its Mechanism Involving Colonic Motility. J Neurogastroenterol Motil 2018; 24:479-489. [PMID: 29715711 PMCID: PMC6034674 DOI: 10.5056/jnm17093] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 10/21/2017] [Accepted: 11/20/2017] [Indexed: 12/13/2022] Open
Abstract
Background/Aims This study was designed to investigate the effect of Fengliao-Changweikang (FLCWK) in diarrhea-predominant irritable bowel syndrome (IBS-D) rats and explore its underlying mechanisms. Methods IBS-D model rats were induced by neonatal maternal separation (NMS) combined with restraint stress (RS). In in vivo experiments, the model rats were randomly divided into 5 groups: NMS + RS, FLCWK (low dose, middle dose, and high dose), and pinaverium bromide. The normal control (no handling) rats were classified as the NH group. The therapeutic effect of FLCWK was evaluated by fecal characteristics, electromyographic response and abdominal withdrawal reflex scores. In in vitro experiments, the model rats were randomly divided into 2 groups: NMS + RS, FLCWK (middle dose), and no handling rats were used as the NH group. The differences in basic tension and ACh-induced tension of isolated colonic longitudinal smooth muscle strips (CLSMs) among the 3 groups were observed. In addition, different inhibitors (nifedipine, TMB-8, L-NAME, methylene blue, and 4-AP) were pretreated to explore the underlying mechanisms. Results In in vivo experiments, fecal characteristics, electromyographic response, and abdominal withdrawal reflex scores significantly improved in the FLCWK group, compared with the NMS + RS group. In in vitro experiments, the basic tension and ACh-induced tension of CLSMs in IBS-D rats were significantly inhibited by FLCWK. After pre-treatment with different inhibitors, the ACh-induced tension of CLSMs in each group showed no significant difference. Conclusions FLCWK manifested curative effect in IBS-D rats by inhibiting colonic contraction. The underlying mechanisms may be related to regulatory pathway of nitric oxide/cGMP/Ca2+ and specific potassium channels.
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Affiliation(s)
- Mengdi Jia
- Digestive Disease Center, Beijing Hospital of Traditional Chinese Medicine Affiliated to Capital Medical University, Beijing, China
| | - Xiaofang Lu
- Digestive Disease Center, Beijing Hospital of Traditional Chinese Medicine Affiliated to Capital Medical University, Beijing, China
| | - Zhengfang Wang
- Digestive Disease Center, Beijing Hospital of Traditional Chinese Medicine Affiliated to Capital Medical University, Beijing, China
| | - Luqing Zhao
- Digestive Disease Center, Beijing Hospital of Traditional Chinese Medicine Affiliated to Capital Medical University, Beijing, China
| | - Shengsheng Zhang
- Digestive Disease Center, Beijing Hospital of Traditional Chinese Medicine Affiliated to Capital Medical University, Beijing, China
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Kringel D, Lippmann C, Parnham MJ, Kalso E, Ultsch A, Lötsch J. A machine-learned analysis of human gene polymorphisms modulating persisting pain points to major roles of neuroimmune processes. Eur J Pain 2018; 22:1735-1756. [PMID: 29923268 PMCID: PMC6220816 DOI: 10.1002/ejp.1270] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2018] [Indexed: 12/21/2022]
Abstract
Background Human genetic research has implicated functional variants of more than one hundred genes in the modulation of persisting pain. Artificial intelligence and machine‐learning techniques may combine this knowledge with results of genetic research gathered in any context, which permits the identification of the key biological processes involved in chronic sensitization to pain. Methods Based on published evidence, a set of 110 genes carrying variants reported to be associated with modulation of the clinical phenotype of persisting pain in eight different clinical settings was submitted to unsupervised machine‐learning aimed at functional clustering. Subsequently, a mathematically supported subset of genes, comprising those most consistently involved in persisting pain, was analysed by means of computational functional genomics in the Gene Ontology knowledgebase. Results Clustering of genes with evidence for a modulation of persisting pain elucidated a functionally heterogeneous set. The situation cleared when the focus was narrowed to a genetic modulation consistently observed throughout several clinical settings. On this basis, two groups of biological processes, the immune system and nitric oxide signalling, emerged as major players in sensitization to persisting pain, which is biologically highly plausible and in agreement with other lines of pain research. Conclusions The present computational functional genomics‐based approach provided a computational systems‐biology perspective on chronic sensitization to pain. Human genetic control of persisting pain points to the immune system as a source of potential future targets for drugs directed against persisting pain. Contemporary machine‐learned methods provide innovative approaches to knowledge discovery from previous evidence. Significance We show that knowledge discovery in genetic databases and contemporary machine‐learned techniques can identify relevant biological processes involved in Persitent pain.
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Affiliation(s)
- D Kringel
- Institute of Clinical Pharmacology, Goethe - University, Frankfurt am Main, Germany
| | - C Lippmann
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Branch for Translational Medicine and Pharmacology TMP, Frankfurt
| | - M J Parnham
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Branch for Translational Medicine and Pharmacology TMP, Frankfurt
| | - E Kalso
- Institute of Clinical Medicine, University of Helsinki, Pain Clinic, Helsinki University Central Hospital, Helsinki, Finland.,Institute of Biomedicine, Pharmacology, University of Helsinki, Helsinki, Finland
| | - A Ultsch
- DataBionics Research Group, University of Marburg, Germany
| | - J Lötsch
- Institute of Clinical Pharmacology, Goethe - University, Frankfurt am Main, Germany.,Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Branch for Translational Medicine and Pharmacology TMP, Frankfurt
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Han D, Tan H, Sun C, Li G. Dysfunctional Nav1.5 channels due to SCN5A mutations. Exp Biol Med (Maywood) 2018; 243:852-863. [PMID: 29806494 DOI: 10.1177/1535370218777972] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The voltage-gated sodium channel 1.5 (Nav1.5), encoded by the SCN5A gene, is responsible for the rising phase of the action potential of cardiomyocytes. The sodium current mediated by Nav1.5 consists of peak and late components (INa-P and INa-L). Mutant Nav1.5 causes alterations in the peak and late sodium current and is associated with an increasingly wide range of congenital arrhythmias. More than 400 mutations have been identified in the SCN5A gene. Although the mechanisms of SCN5A mutations leading to a variety of arrhythmias can be classified according to the alteration of INa-P and INa-L as gain-of-function, loss-of-function and both, few researchers have summarized the mechanisms in this way before. In this review article, we aim to review the mechanisms underlying dysfunctional Nav1.5 due to SCN5A mutations and to provide some new insights into further approaches in the treatment of arrhythmias. Impact statement The field of ion channelopathy caused by dysfunctional Nav1.5 due to SCN5A mutations is rapidly evolving as novel technologies of electrophysiology are introduced and our understanding of the mechanisms of various arrhythmias develops. In this review, we focus on the dysfunctional Nav1.5 related to arrhythmias and the underlying mechanisms. We update SCN5A mutations in a precise way since 2013 and presents novel classifications of SCN5A mutations responsible for the dysfunction of the peak (INa-P) and late (INa-L) sodium channels based on their phenotypes, including loss-, gain-, and coexistence of gain- and loss-of function mutations in INa-P, INa-L, respectively. We hope this review will provide a new comprehensive way to better understand the electrophysiological mechanisms underlying arrhythmias from cell to bedside, promoting the management of various arrhythmias in practice.
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Affiliation(s)
- Dan Han
- 1 Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, P.R. China
| | - Hui Tan
- 2 Department of Respiratory Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, P.R. China
| | - Chaofeng Sun
- 1 Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, P.R. China
| | - Guoliang Li
- 1 Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, P.R. China
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Strege PR, Mazzone A, Bernard CE, Neshatian L, Gibbons SJ, Saito YA, Tester DJ, Calvert ML, Mayer EA, Chang L, Ackerman MJ, Beyder A, Farrugia G. Irritable bowel syndrome patients have SCN5A channelopathies that lead to decreased Na V1.5 current and mechanosensitivity. Am J Physiol Gastrointest Liver Physiol 2018; 314:G494-G503. [PMID: 29167113 PMCID: PMC5966747 DOI: 10.1152/ajpgi.00016.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The SCN5A-encoded voltage-gated mechanosensitive Na+ channel NaV1.5 is expressed in human gastrointestinal smooth muscle cells and interstitial cells of Cajal. NaV1.5 contributes to smooth muscle electrical slow waves and mechanical sensitivity. In predominantly Caucasian irritable bowel syndrome (IBS) patient cohorts, 2-3% of patients have SCN5A missense mutations that alter NaV1.5 function and may contribute to IBS pathophysiology. In this study we examined a racially and ethnically diverse cohort of IBS patients for SCN5A missense mutations, compared them with IBS-negative controls, and determined the resulting NaV1.5 voltage-dependent and mechanosensitive properties. All SCN5A exons were sequenced from somatic DNA of 252 Rome III IBS patients with diverse ethnic and racial backgrounds. Missense mutations were introduced into wild-type SCN5A by site-directed mutagenesis and cotransfected with green fluorescent protein into HEK-293 cells. NaV1.5 voltage-dependent and mechanosensitive functions were studied by whole cell electrophysiology with and without shear force. Five of 252 (2.0%) IBS patients had six rare SCN5A mutations that were absent in 377 IBS-negative controls. Six of six (100%) IBS-associated NaV1.5 mutations had voltage-dependent gating abnormalities [current density reduction (R225W, R433C, R986Q, and F1293S) and altered voltage dependence (R225W, R433C, R986Q, G1037V, and F1293S)], and at least one kinetic parameter was altered in all mutations. Four of six (67%) IBS-associated SCN5A mutations (R225W, R433C, R986Q, and F1293S) resulted in altered NaV1.5 mechanosensitivity. In this racially and ethnically diverse cohort of IBS patients, we show that 2% of IBS patients harbor SCN5A mutations that are absent in IBS-negative controls and result in NaV1.5 channels with abnormal voltage-dependent and mechanosensitive function. NEW & NOTEWORTHY The voltage-gated Na+ channel NaV1.5 contributes to smooth muscle physiology and electrical slow waves. In a racially and ethnically mixed irritable bowel syndrome cohort, 2% had mutations in the NaV1.5 gene SCN5A. These mutations were absent in irritable bowel syndrome-negative controls. Most mutant NaV1.5 channels were loss of function in voltage dependence or mechanosensitivity.
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Affiliation(s)
- Peter R. Strege
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Amelia Mazzone
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Cheryl E. Bernard
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Leila Neshatian
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Simon J. Gibbons
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Yuri A. Saito
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - David J. Tester
- 2Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Melissa L. Calvert
- 2Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Emeran A. Mayer
- 3Oppenheimer Center for Neurobiology of Stress and Resilience, Division of Digestive Diseases, University of California Los Angeles, Los Angeles, California
| | - Lin Chang
- 3Oppenheimer Center for Neurobiology of Stress and Resilience, Division of Digestive Diseases, University of California Los Angeles, Los Angeles, California
| | - Michael J. Ackerman
- 2Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Arthur Beyder
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Gianrico Farrugia
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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Erickson A, Deiteren A, Harrington AM, Garcia‐Caraballo S, Castro J, Caldwell A, Grundy L, Brierley SM. Voltage-gated sodium channels: (Na V )igating the field to determine their contribution to visceral nociception. J Physiol 2018; 596:785-807. [PMID: 29318638 PMCID: PMC5830430 DOI: 10.1113/jp273461] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 01/02/2018] [Indexed: 12/19/2022] Open
Abstract
Chronic visceral pain, altered motility and bladder dysfunction are common, yet poorly managed symptoms of functional and inflammatory disorders of the gastrointestinal and urinary tracts. Recently, numerous human channelopathies of the voltage-gated sodium (NaV ) channel family have been identified, which induce either painful neuropathies, an insensitivity to pain, or alterations in smooth muscle function. The identification of these disorders, in addition to the recent utilisation of genetically modified NaV mice and specific NaV channel modulators, has shed new light on how NaV channels contribute to the function of neuronal and non-neuronal tissues within the gastrointestinal tract and bladder. Here we review the current pre-clinical and clinical evidence to reveal how the nine NaV channel family members (NaV 1.1-NaV 1.9) contribute to abdominal visceral function in normal and disease states.
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Affiliation(s)
- Andelain Erickson
- Visceral Pain Research Group, Human Physiology, Centre for Neuroscience, College of Medicine and Public HealthFlinders UniversityBedford ParkSouth Australia5042Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of AdelaideSouth Australian Health and Medical Research Institute (SAHMRI)North TerraceAdelaideSouth Australia 5000Australia
| | - Annemie Deiteren
- Visceral Pain Research Group, Human Physiology, Centre for Neuroscience, College of Medicine and Public HealthFlinders UniversityBedford ParkSouth Australia5042Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of AdelaideSouth Australian Health and Medical Research Institute (SAHMRI)North TerraceAdelaideSouth Australia 5000Australia
| | - Andrea M. Harrington
- Visceral Pain Research Group, Human Physiology, Centre for Neuroscience, College of Medicine and Public HealthFlinders UniversityBedford ParkSouth Australia5042Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of AdelaideSouth Australian Health and Medical Research Institute (SAHMRI)North TerraceAdelaideSouth Australia 5000Australia
| | - Sonia Garcia‐Caraballo
- Visceral Pain Research Group, Human Physiology, Centre for Neuroscience, College of Medicine and Public HealthFlinders UniversityBedford ParkSouth Australia5042Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of AdelaideSouth Australian Health and Medical Research Institute (SAHMRI)North TerraceAdelaideSouth Australia 5000Australia
| | - Joel Castro
- Visceral Pain Research Group, Human Physiology, Centre for Neuroscience, College of Medicine and Public HealthFlinders UniversityBedford ParkSouth Australia5042Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of AdelaideSouth Australian Health and Medical Research Institute (SAHMRI)North TerraceAdelaideSouth Australia 5000Australia
| | - Ashlee Caldwell
- Visceral Pain Research Group, Human Physiology, Centre for Neuroscience, College of Medicine and Public HealthFlinders UniversityBedford ParkSouth Australia5042Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of AdelaideSouth Australian Health and Medical Research Institute (SAHMRI)North TerraceAdelaideSouth Australia 5000Australia
| | - Luke Grundy
- Visceral Pain Research Group, Human Physiology, Centre for Neuroscience, College of Medicine and Public HealthFlinders UniversityBedford ParkSouth Australia5042Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of AdelaideSouth Australian Health and Medical Research Institute (SAHMRI)North TerraceAdelaideSouth Australia 5000Australia
| | - Stuart M. Brierley
- Visceral Pain Research Group, Human Physiology, Centre for Neuroscience, College of Medicine and Public HealthFlinders UniversityBedford ParkSouth Australia5042Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of AdelaideSouth Australian Health and Medical Research Institute (SAHMRI)North TerraceAdelaideSouth Australia 5000Australia
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31
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Holtmann G, Shah A, Morrison M. Pathophysiology of Functional Gastrointestinal Disorders: A Holistic Overview. Dig Dis 2018; 35 Suppl 1:5-13. [PMID: 29421808 DOI: 10.1159/000485409] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Background and Summary: Traditionally, functional gastrointestinal disorders (FGID), including functional dyspepsia or irritable bowel syndrome (IBS), are defined by more or less specific symptoms and the absence of structural or biochemical abnormalities that cause these symptoms. This concept is now considered to be outdated; if appropriate tests are applied, structural or biochemical abnormalities that explain or cause the symptoms may be found in many patients. Another feature of FGID are the highly prevalent psychiatric comorbidities, such as depression and anxiety. It is implied that mood disorders "cause" gastrointestinal symptoms. In fact, epidemiological data now provide strong evidence that in subsets of cases, gastrointestinal (GI) symptoms arise first and mood disorders occur later, while in other patients the reverse appears to happen. Possible mechanisms for gut-brain dysfunction have been identified, with systemic minimal inflammation as a causal factor in at least some subjects. Other mechanisms that play a role in FGID include chronic infections, intestinal microbiota, low-grade mucosal inflammation including the increase of eosinophils, systemic immune activation, altered intestinal permeability, in diarrhea predominant IBS altered bile salt metabolism, abnormalities in the serotonin metabolism and genetic factors. All these factors might be modulated by environmental factors such as diet. Key Messages: While a number of factors can be linked to specific symptoms (e.g., pain or diarrhea), it is evident that the symptom-based categorization of patients will not allow targeted treatments that specifically address the underlying pathophysiology.
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Affiliation(s)
- Gerald Holtmann
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia.,Faculty of Medicine and Falty of Health and Behavioural Sciences, University of Queensland, Queensland, Queensland, Australia
| | - Ayesha Shah
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia
| | - Mark Morrison
- Diamantina Institute, University of Queensland, Queensland, Queensland, Australia
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32
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Cai YY, Li C, Yan ZX, Ma N, Li FF. Effects of SCN9A gene modification on Na+ channel and the expression of nerve growth factor in a rat model of diarrhea‑predominant irritable bowel syndrome. Mol Med Rep 2017; 17:1839-1846. [PMID: 29138838 DOI: 10.3892/mmr.2017.8061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 08/24/2017] [Indexed: 11/06/2022] Open
Abstract
The aim of the present study was to identify whether the sodium voltage-gated channel alpha subunit 9 (SCN9A) gene modification is a potential treatment for diarrhea‑predominant irritable bowel syndrome (D‑IBS), via regulating the Na+ channel and the expression of nerve growth factor (NGF). The recombinant adenovirus vector of the SCN9A gene was established, and rat colon cells were isolated for SCN9A gene modification. All subjects were divided into four groups: i) The SCN9A‑modified (D‑IBS rat model implanted with SCN9A‑modified colon cells), ii) negative control (NC; D‑IBS rat model implanted with colon cells without SCN9A gene modification), iii) blank (D‑IBS rat model without any treatment) and iv) normal (normal rats without any treatment). Western blotting and reverse transcription‑quantitative polymerase chain reaction were used to detect the protein and mRNA expression levels of SCN9A, NGF and voltage gated sodium channels (Nav)1.8 and Nav1.9 in rat colon tissues. Compared with the normal group, the rats in the SCN9A, NC and blank groups had significantly elevated mRNA and protein expression levels of NGF, SCN9A, Nav1.8 and Nav1.9. The rats in the SCN9A group demonstrated significantly increased mRNA and protein expression levels of NGF, SCN9A, Nav1.8 and Nav1.9 compared with the NC group and the blank group (all P<0.05). SCN9A gene modification can promote the expression of Nav1.8 and Nav1.9 channels, in addition to NGF which may provide a novel therapeutic basis for treating of D‑IBS.
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Affiliation(s)
- Yong-Yan Cai
- The First Department of Pediatric Medicinel, Cangzhou Central Hospital, Cangzhou, Hebei 061000, P.R. China
| | - Chen Li
- The Fifth Department of Pediatric Medicine, Cangzhou Central Hospital, Cangzhou, Hebei 061000, P.R. China
| | - Zhi-Xin Yan
- The First Department of Pediatric Medicinel, Cangzhou Central Hospital, Cangzhou, Hebei 061000, P.R. China
| | - Na Ma
- The First Department of Pediatric Medicinel, Cangzhou Central Hospital, Cangzhou, Hebei 061000, P.R. China
| | - Fang-Fang Li
- The First Department of Pediatric Medicinel, Cangzhou Central Hospital, Cangzhou, Hebei 061000, P.R. China
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33
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Roston TM, Cunningham T, Lehman A, Laksman ZW, Krahn AD, Sanatani S. Beyond the Electrocardiogram: Mutations in Cardiac Ion Channel Genes Underlie Nonarrhythmic Phenotypes. CLINICAL MEDICINE INSIGHTS-CARDIOLOGY 2017; 11:1179546817698134. [PMID: 28469493 PMCID: PMC5392026 DOI: 10.1177/1179546817698134] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 02/01/2017] [Indexed: 12/19/2022]
Abstract
Cardiac ion channelopathies are an important cause of sudden death in the young and include long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, idiopathic ventricular fibrillation, and short QT syndrome. Genes that encode ion channels have been implicated in all of these conditions, leading to the widespread implementation of genetic testing for suspected channelopathies. Over the past half-century, researchers have also identified systemic pathologies that extend beyond the arrhythmic phenotype in patients with ion channel gene mutations, including deafness, epilepsy, cardiomyopathy, periodic paralysis, and congenital heart disease. A coexisting phenotype, such as cardiomyopathy, can influence evaluation and management. However, prior to recent molecular advances, our understanding and recognition of these overlapping phenotypes were poor. This review highlights the systemic and structural heart manifestations of the cardiac ion channelopathies, including their phenotypic spectrum and molecular basis.
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Affiliation(s)
- Thomas M Roston
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada
| | - Taylor Cunningham
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada
| | - Anna Lehman
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada
| | - Zachary W Laksman
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada
| | - Andrew D Krahn
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada
| | - Shubhayan Sanatani
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada.,Children's Heart Centre, BC Children's Hospital, Vancouver, BC, Canada
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34
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Madan N, Carvalho KS. Neurological Complications of Cardiac Disease. Semin Pediatr Neurol 2017; 24:3-13. [PMID: 28779863 DOI: 10.1016/j.spen.2017.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This article focuses on the complex interactions between the cardiovascular and neurologic systems. Initially, we focus on neurological complications in children with congenital heart disease both secondary to the underlying cardiac disease and complications of interventions. We later discuss diagnosis and management of common syncope syndromes with emphasis on vasovagal syncope. We also review the diagnosis, classification, and management of children and adolescents with postural orthostatic tachycardia syndrome. Lastly, we discuss long QT syndrome and sudden unexpected death in epilepsy (SUDEP), reviewing advances in genetics and current knowledge of pathophysiology of these conditions. This article attempts to provide an overview of these disorders with focus on pathophysiology, advances in molecular genetics, and current medical interventions.
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Affiliation(s)
- Nandini Madan
- From the Section of Cardiology, Department of Pediatrics, St. Christopher's Hospital for Children, Drexel University College of Medicine, Philadelphia, PA.
| | - Karen S Carvalho
- Section of Neurology, Department of Pediatrics, St. Christopher's Hospital for Children, Drexel University College of Medicine, Philadelphia, PA
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35
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Alcaino C, Knutson K, Gottlieb PA, Farrugia G, Beyder A. Mechanosensitive ion channel Piezo2 is inhibited by D-GsMTx4. Channels (Austin) 2017; 11:245-253. [PMID: 28085630 DOI: 10.1080/19336950.2017.1279370] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Enterochromaffin (EC) cells are the primary mechanosensors of the gastrointestinal (GI) epithelium. In response to mechanical stimuliEC cells release serotonin (5-hydroxytryptamine; 5-HT). The molecular details ofEC cell mechanosensitivity are poorly understood. Recently, our group found that human and mouseEC cells express the mechanosensitive ion channel Piezo2. The mechanosensitive currents in a humanEC cell model QGP-1 were blocked by the mechanosensitive channel blocker D-GsMTx4. In the present study we aimed to characterize the effects of the mechanosensitive ion channel inhibitor spider peptide D-GsMTx4 on the mechanically stimulated currents from both QGP-1 and human Piezo2 transfected HEK-293 cells. We found co-localization of 5-HT and Piezo2 in QGP-1 cells by immunohistochemistry. QGP-1 mechanosensitive currents had biophysical properties similar to dose-dependently Piezo2 and were inhibited by D-GsMTx4. In response to direct displacement of cell membranes, human Piezo2 transiently expressed in HEK-293 cells produced robust rapidly activating and inactivating inward currents. D-GsMTx4 reversibly and dose-dependently inhibited both the potency and efficacy of Piezo2 currents in response to mechanical force. Our data demonstrate an effective inhibition of Piezo2 mechanosensitive currents by the spider peptide D-GsMTx4.
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Affiliation(s)
- Constanza Alcaino
- a Department of Physiology & Biomedical Engineering, Enteric Neuroscience Program, Division of Gastroenterology & Hepatology , Mayo Clinic , Rochester , MN , USA
| | - Kaitlyn Knutson
- a Department of Physiology & Biomedical Engineering, Enteric Neuroscience Program, Division of Gastroenterology & Hepatology , Mayo Clinic , Rochester , MN , USA
| | - Philip A Gottlieb
- b Department of Physiology and Biophysics, Center for Single Molecule Biophysics , State University of New York , Buffalo , NY , USA
| | - Gianrico Farrugia
- b Department of Physiology and Biophysics, Center for Single Molecule Biophysics , State University of New York , Buffalo , NY , USA
| | - Arthur Beyder
- a Department of Physiology & Biomedical Engineering, Enteric Neuroscience Program, Division of Gastroenterology & Hepatology , Mayo Clinic , Rochester , MN , USA
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36
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Alcaino C, Farrugia G, Beyder A. Mechanosensitive Piezo Channels in the Gastrointestinal Tract. CURRENT TOPICS IN MEMBRANES 2017; 79:219-244. [PMID: 28728818 PMCID: PMC5606247 DOI: 10.1016/bs.ctm.2016.11.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Sensation of mechanical forces is critical for normal function of the gastrointestinal (GI) tract and abnormalities in mechanosensation are linked to GI pathologies. In the GI tract there are several mechanosensitive cell types-epithelial enterochromaffin cells, intrinsic and extrinsic enteric neurons, smooth muscle cells and interstitial cells of Cajal. These cells use mechanosensitive ion channels that respond to mechanical forces by altering transmembrane ionic currents in a process called mechanoelectrical coupling. Several mechanosensitive ionic conductances have been identified in the mechanosensory GI cells, ranging from mechanosensitive voltage-gated sodium and calcium channels to the mechanogated ion channels, such as the two-pore domain potassium channels K2P (TREK-1) and nonselective cation channels from the transient receptor potential family. The recently discovered Piezo channels are increasingly recognized as significant contributors to cellular mechanosensitivity. Piezo1 and Piezo2 are nonselective cationic ion channels that are directly activated by mechanical forces and have well-defined biophysical and pharmacologic properties. The role of Piezo channels in the GI epithelium is currently under investigation and their role in the smooth muscle syncytium and enteric neurons is still not known. In this review, we outline the current state of knowledge on mechanosensitive ion channels in the GI tract, with a focus on the known and potential functions of the Piezo channels.
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Affiliation(s)
- C Alcaino
- Mayo Clinic College of Medicine, Rochester, MN, United States
| | - G Farrugia
- Mayo Clinic College of Medicine, Rochester, MN, United States
| | - A Beyder
- Mayo Clinic College of Medicine, Rochester, MN, United States
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37
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Beyder A, Farrugia G. Ion channelopathies in functional GI disorders. Am J Physiol Gastrointest Liver Physiol 2016; 311:G581-G586. [PMID: 27514480 PMCID: PMC5142191 DOI: 10.1152/ajpgi.00237.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/07/2016] [Indexed: 01/31/2023]
Abstract
In the gastrointestinal (GI) tract, abnormalities in secretion, absorption, motility, and sensation have been implicated in functional gastrointestinal disorders (FGIDs). Ion channels play important roles in all these GI functions. Disruptions of ion channels' ability to conduct ions can lead to diseases called ion channelopathies. Channelopathies can result from changes in ion channel biophysical function or expression due to mutations, posttranslational modification, and accessory protein malfunction. Channelopathies are strongly established in the fields of cardiology and neurology, but ion channelopathies are only beginning to be recognized in gastroenterology. In this review, we describe the state of the emerging field of GI ion channelopathies. Several recent discoveries show that channelopathies result in alterations in GI motility, secretion, and sensation. In the epithelium, mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) or CFTR-associating proteins result in channelopathies with constipation or diarrhea as phenotypes. In the muscle, mutations in the SCN5A-encoded voltage-gated sodium channel NaV1.5 are associated with irritable bowel syndrome. In the sensory nerves, channelopathies of voltage-gated sodium channels NaV1.7 and NaV1.9 (encoded by SCN9A, SCN11A, respectively) manifest by either GI hyper- or hyposensation. Recent advances in structural biology and ion channel biophysics, coupled with personalized medicine, have fueled rapid discoveries of novel channelopathies and direct drug targeting of specific channelopathies. In summary, the emerging field of GI ion channelopathies has significant implications for functional GI disease stratification, diagnosis, and treatment.
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Affiliation(s)
- Arthur Beyder
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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38
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Holtmann GJ, Ford AC, Talley NJ. Pathophysiology of irritable bowel syndrome. Lancet Gastroenterol Hepatol 2016; 1:133-146. [DOI: 10.1016/s2468-1253(16)30023-1] [Citation(s) in RCA: 256] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 06/20/2016] [Accepted: 06/24/2016] [Indexed: 11/25/2022]
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39
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Medland JE, Pohl CS, Edwards LL, Frandsen S, Bagley K, Li Y, Moeser AJ. Early life adversity in piglets induces long-term upregulation of the enteric cholinergic nervous system and heightened, sex-specific secretomotor neuron responses. Neurogastroenterol Motil 2016; 28:1317-29. [PMID: 27134125 PMCID: PMC5002263 DOI: 10.1111/nmo.12828] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 03/04/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND Early life adversity (ELA) is a risk factor for the later-life onset of gastrointestinal (GI) diseases such as irritable bowel syndrome (IBS); however, the mechanisms are poorly understood. Here, we utilized a porcine model of ELA, early weaning stress (EWS), to investigate the influence of ELA on the development and function of the enteric nervous system (ENS). METHODS Female and castrated male (Male-C) piglets were weaned from their sow either at 15 days of age (EWS) or 28 days of age (late weaning control, LWC). At 60 and 170 days of age, ileal mucosa-submucosa preparations were mounted in Ussing chambers and veratridine- and corticotropin releasing factor (CRF)-releasing factor-evoked short circuit current (Isc ) responses were recorded as indices of secretomotor neuron function. Enteric neuron numbers and the expression of select neurotransmitters and their receptors were also measured. KEY RESULTS Compared with LWC pigs, female, but not Male-C EWS, pigs exhibited heightened veratridine-induced Isc responses at 60 and 170 days of age that were inhibited with tetrodotoxin and atropine. Ileum from EWS pigs had higher numbers of enteric neurons that were choline acetyltransferase positive. Markers of increased cholinergic signaling (increased acetylcholinesterase) and downregulated mucosal muscarinic receptor 3 gene expression were also observed in EWS pigs. CONCLUSIONS & INFERENCES This study demonstrated that EWS in pigs induces lasting and sex-specific hypersensitivity of secretomotor neuron function and upregulation of the cholinergic ENS. These findings may represent a mechanistic link between ELA and lifelong susceptibility to GI diseases such as IBS.
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Affiliation(s)
- Julia E. Medland
- Comparative Biomedical Sciences Program, North Carolina State University, College of Veterinary Medicine, Raleigh, NC 27607, USA
| | - Calvin S. Pohl
- Gastrointestinal Stress Biology Laboratory, Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, MI 48824, USA
| | - Laura L. Edwards
- Department of Population Health and Pathobiology, North Carolina State University, College of Veterinary Medicine, Raleigh, NC 27607, USA
| | - Shellsea Frandsen
- Department of Population Health and Pathobiology, North Carolina State University, College of Veterinary Medicine, Raleigh, NC 27607, USA
| | - Kristen Bagley
- Department of Population Health and Pathobiology, North Carolina State University, College of Veterinary Medicine, Raleigh, NC 27607, USA
| | - Yihang Li
- Gastrointestinal Stress Biology Laboratory, Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, MI 48824, USA
| | - Adam J. Moeser
- Gastrointestinal Stress Biology Laboratory, Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, MI 48824, USA,Neuroscience Program, Michigan State University
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40
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Wang F, Knutson K, Alcaino C, Linden DR, Gibbons SJ, Kashyap P, Grover M, Oeckler R, Gottlieb PA, Li HJ, Leiter AB, Farrugia G, Beyder A. Mechanosensitive ion channel Piezo2 is important for enterochromaffin cell response to mechanical forces. J Physiol 2016; 595:79-91. [PMID: 27392819 DOI: 10.1113/jp272718] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 06/29/2016] [Indexed: 12/31/2022] Open
Abstract
KEY POINTS The gastrointestinal epithelial enterochromaffin (EC) cell synthesizes the vast majority of the body's serotonin. As a specialized mechanosensor, the EC cell releases this serotonin in response to mechanical forces. However, the molecular mechanism of EC cell mechanotransduction is unknown. In the present study, we show, for the first time, that the mechanosensitive ion channel Piezo2 is specifically expressed by the human and mouse EC cells. Activation of Piezo2 by mechanical forces results in a characteristic ionic current, the release of serotonin and stimulation of gastrointestinal secretion. Piezo2 inhibition by drugs or molecular knockdown decreases mechanosensitive currents, serotonin release and downstream physiological effects. The results of the present study suggest that the mechanosensitive ion channel Piezo2 is specifically expressed by the EC cells of the human and mouse small bowel and that it is important for EC cell mechanotransduction. ABSTRACT The enterochromaffin (EC) cell in the gastrointestinal (GI) epithelium is the source of nearly all systemic serotonin (5-hydroxytryptamine; 5-HT), which is an important neurotransmitter and endocrine, autocrine and paracrine hormone. The EC cell is a specialized mechanosensor, and it is well known that it releases 5-HT in response to mechanical forces. However, the EC cell mechanotransduction mechanism is unknown. The present study aimed to determine whether Piezo2 is involved in EC cell mechanosensation. Piezo2 mRNA was expressed in human jejunum and mouse mucosa from all segments of the small bowel. Piezo2 immunoreactivity localized specifically within EC cells of human and mouse small bowel epithelium. The EC cell model released 5-HT in response to stretch, and had Piezo2 mRNA and protein, as well as a mechanically-sensitive inward non-selective cation current characteristic of Piezo2. Both inward currents and 5-HT release were inhibited by Piezo2 small interfering RNA and antagonists (Gd3+ and D-GsMTx4). Jejunum mucosal pressure increased 5-HT release and short-circuit current via submucosal 5-HT3 and 5-HT4 receptors. Pressure-induced secretion was inhibited by the mechanosensitive ion channel antagonists gadolinium, ruthenium red and D-GsMTx4. We conclude that the EC cells in the human and mouse small bowel GI epithelium selectively express the mechanosensitive ion channel Piezo2, and also that activation of Piezo2 by force leads to inward currents, 5-HT release and an increase in mucosal secretion. Therefore, Piezo2 is critical to EC cell mechanosensitivity and downstream physiological effects.
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Affiliation(s)
- Fan Wang
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Departments of Medicine and Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA.,Department of Gastroenterology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 300 Yanchang Middle Road, Shanghai, PR China
| | - Kaitlyn Knutson
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Departments of Medicine and Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
| | - Constanza Alcaino
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Departments of Medicine and Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
| | - David R Linden
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Departments of Medicine and Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
| | - Simon J Gibbons
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Departments of Medicine and Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
| | - Purna Kashyap
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Departments of Medicine and Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
| | - Madhusudan Grover
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Departments of Medicine and Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
| | - Richard Oeckler
- Division of Pulmonary and Critical Care, Departments of Medicine and Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
| | - Philip A Gottlieb
- Department of Physiology and Biophysics, State University of New York at Buffalo, 3435 Main Street, Buffalo, NY, USA
| | - Hui Joyce Li
- Department of Medicine, Division of Gastroenterology, University of Massachusetts Medical School, 55 N Lake Ave, Worcester, MA, USA
| | - Andrew B Leiter
- Department of Medicine, Division of Gastroenterology, University of Massachusetts Medical School, 55 N Lake Ave, Worcester, MA, USA
| | - Gianrico Farrugia
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Departments of Medicine and Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
| | - Arthur Beyder
- Enteric Neuroscience Program, Division of Gastroenterology & Hepatology, Departments of Medicine and Physiology & Biomedical Engineering, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
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Auerbach DS, McNitt S, Gross RA, Zareba W, Dirksen RT, Moss AJ. Genetic biomarkers for the risk of seizures in long QT syndrome. Neurology 2016; 87:1660-1668. [PMID: 27466471 DOI: 10.1212/wnl.0000000000003056] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/26/2016] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES The coprevalence, severity, and biomarkers for seizures and arrhythmias in long QT syndrome (LQTS) remain incompletely understood. METHODS Using the Rochester-based LQTS Registry, this study included large cohorts of LQTS1-3 participants (LQTS+, n = 965) and those without a LQTS mutation (LQTS-, n = 936). RESULTS Compared to LQTS- participants, there was a higher prevalence of LQTS1, LQTS2, and LQTS+ participants classified as having seizures (p < 0.001, i.e., history of seizures/epilepsy or antiseizure medication). LQTS+ participants with longer corrected QT interval (QTc) durations were more likely to have seizures. LQTS2 mutations in the KCNH2 pore domain were positive predictors for both arrhythmias and seizures. In contrast, mutations in the cyclic nucleotide binding domain (cNBD) of KCNH2 conferred a negative risk of seizures, but not arrhythmias. LQTS2, KCNH2-pore, KCNH2-cNBD, QTc duration, and sex were independent predictors of seizures. LQTS+ participants with seizures had significantly longer QTc durations, and a history of seizures was the strongest independent predictor of arrhythmias (hazard ratio 4.09, 95% confidence interval 2.63-6.36, p < 0.001). CONCLUSIONS This study highlights potential biomarkers for neurocardiac electrical abnormalities in LQTS.
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Affiliation(s)
- David S Auerbach
- From the Department of Medicine, Aab Cardiovascular Research Institute (D.S.A.), Department of Medicine, Heart Research Follow-up Program (S.M., W.Z., A.J.M.), and Departments of Neurology (R.A.G.) and Pharmacology & Physiology (R.A.G., R.T.D.), University of Rochester School of Medicine and Dentistry, Rochester, NY.
| | - Scott McNitt
- From the Department of Medicine, Aab Cardiovascular Research Institute (D.S.A.), Department of Medicine, Heart Research Follow-up Program (S.M., W.Z., A.J.M.), and Departments of Neurology (R.A.G.) and Pharmacology & Physiology (R.A.G., R.T.D.), University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Robert A Gross
- From the Department of Medicine, Aab Cardiovascular Research Institute (D.S.A.), Department of Medicine, Heart Research Follow-up Program (S.M., W.Z., A.J.M.), and Departments of Neurology (R.A.G.) and Pharmacology & Physiology (R.A.G., R.T.D.), University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Wojciech Zareba
- From the Department of Medicine, Aab Cardiovascular Research Institute (D.S.A.), Department of Medicine, Heart Research Follow-up Program (S.M., W.Z., A.J.M.), and Departments of Neurology (R.A.G.) and Pharmacology & Physiology (R.A.G., R.T.D.), University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Robert T Dirksen
- From the Department of Medicine, Aab Cardiovascular Research Institute (D.S.A.), Department of Medicine, Heart Research Follow-up Program (S.M., W.Z., A.J.M.), and Departments of Neurology (R.A.G.) and Pharmacology & Physiology (R.A.G., R.T.D.), University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Arthur J Moss
- From the Department of Medicine, Aab Cardiovascular Research Institute (D.S.A.), Department of Medicine, Heart Research Follow-up Program (S.M., W.Z., A.J.M.), and Departments of Neurology (R.A.G.) and Pharmacology & Physiology (R.A.G., R.T.D.), University of Rochester School of Medicine and Dentistry, Rochester, NY
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Tse G, Lai ETH, Lee APW, Yan BP, Wong SH. Electrophysiological Mechanisms of Gastrointestinal Arrhythmogenesis: Lessons from the Heart. Front Physiol 2016; 7:230. [PMID: 27378939 PMCID: PMC4906021 DOI: 10.3389/fphys.2016.00230] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 05/30/2016] [Indexed: 01/09/2023] Open
Abstract
Disruptions in the orderly activation and recovery of electrical excitation traveling through the heart and the gastrointestinal (GI) tract can lead to arrhythmogenesis. For example, cardiac arrhythmias predispose to thromboembolic events resulting in cerebrovascular accidents and myocardial infarction, and to sudden cardiac death. By contrast, arrhythmias in the GI tract are usually not life-threatening and much less well characterized. However, they have been implicated in the pathogenesis of a number of GI motility disorders, including gastroparesis, dyspepsia, irritable bowel syndrome, mesenteric ischaemia, Hirschsprung disease, slow transit constipation, all of which are associated with significant morbidity. Both cardiac and gastrointestinal arrhythmias can broadly be divided into non-reentrant and reentrant activity. The aim of this paper is to compare and contrast the mechanisms underlying arrhythmogenesis in both systems to provide insight into the pathogenesis of GI motility disorders and potential molecular targets for future therapy.
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Affiliation(s)
- Gary Tse
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, The University of Hong KongHong Kong, China
- Department of Medicine and Therapeutics, The Chinese University of Hong KongHong Kong, China
| | - Eric T. H. Lai
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, The University of Hong KongHong Kong, China
| | - Alex P. W. Lee
- Department of Medicine and Therapeutics, The Chinese University of Hong KongHong Kong, China
| | - Bryan P. Yan
- Department of Medicine and Therapeutics, The Chinese University of Hong KongHong Kong, China
| | - Sunny H. Wong
- Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong KongHong Kong, China
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Tse G, Lai ETH, Yeo JM, Tse V, Wong SH. Mechanisms of Electrical Activation and Conduction in the Gastrointestinal System: Lessons from Cardiac Electrophysiology. Front Physiol 2016; 7:182. [PMID: 27303305 PMCID: PMC4885840 DOI: 10.3389/fphys.2016.00182] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/06/2016] [Indexed: 12/12/2022] Open
Abstract
The gastrointestinal (GI) tract is an electrically excitable organ system containing multiple cell types, which coordinate electrical activity propagating through this tract. Disruption in its normal electrophysiology is observed in a number of GI motility disorders. However, this is not well characterized and the field of GI electrophysiology is much less developed compared to the cardiac field. The aim of this article is to use the established knowledge of cardiac electrophysiology to shed light on the mechanisms of electrical activation and propagation along the GI tract, and how abnormalities in these processes lead to motility disorders and suggest better treatment options based on this improved understanding. In the first part of the article, the ionic contributions to the generation of GI slow wave and the cardiac action potential (AP) are reviewed. Propagation of these electrical signals can be described by the core conductor theory in both systems. However, specifically for the GI tract, the following unique properties are observed: changes in slow wave frequency along its length, periods of quiescence, synchronization in short distances and desynchronization over long distances. These are best described by a coupled oscillator theory. Other differences include the diminished role of gap junctions in mediating this conduction in the GI tract compared to the heart. The electrophysiology of conditions such as gastroesophageal reflux disease and gastroparesis, and functional problems such as irritable bowel syndrome are discussed in detail, with reference to ion channel abnormalities and potential therapeutic targets. A deeper understanding of the molecular basis and physiological mechanisms underlying GI motility disorders will enable the development of better diagnostic and therapeutic tools and the advancement of this field.
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Affiliation(s)
- Gary Tse
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
| | - Eric Tsz Him Lai
- Li Ka Shing Faculty of Medicine, School of Biomedical Sciences, University of Hong KongHong Kong, China
| | - Jie Ming Yeo
- School of Medicine, Imperial College LondonLondon, UK
| | - Vivian Tse
- Department of Physiology, McGill UniversityMontreal, QC, Canada
| | - Sunny Hei Wong
- Department of Medicine and Therapeutics, Institute of Digestive Disease, LKS Institute of Health Sciences, Chinese University of Hong KongHong Kong, China
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Abstract
IBS is the most prevalent functional gastrointestinal disorder and phenotypically characterized by chronic abdominal discomfort, pain and altered defecation patterns. The pathophysiology of IBS is multifactorial, albeit with a substantial genetic component. To date, studies using various methodologies, ranging from family and twin studies to candidate gene approaches and genome-wide association studies, have identified several genetic variants in the context of IBS. Yet, despite enlarged sample sizes, increased statistical power and meta-analyses in the past 7 years, positive associations are still scarce and/or have not been reproduced. In addition, epigenetic and pharmacogenetic approaches remain in their infancy. A major hurdle is the lack of large homogenized case-control cohorts recruited according to standardized and harmonized criteria. The COST Action BM1106 GENIEUR (GENes in Irritable Bowel Syndrome Research Network EURope) has been established to address these obstacles. In this Review, the (epi)genetic working group of GENIEUR reports on the current state-of-the-art in the field, highlights fundamental flaws and pitfalls in current IBS (epi)genetic research and provides a vision on how to address and improve (epi)genetic approaches in this complex disorder in the future.
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Beyder A, Gibbons SJ, Mazzone A, Strege PR, Saravanaperumal SA, Sha L, Higgins S, Eisenman ST, Bernard CE, Geurts A, Kline CF, Mohler PJ, Farrugia G. Expression and function of the Scn5a-encoded voltage-gated sodium channel NaV 1.5 in the rat jejunum. Neurogastroenterol Motil 2016; 28:64-73. [PMID: 26459913 PMCID: PMC4688076 DOI: 10.1111/nmo.12697] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 09/05/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND The SCN5A-encoded voltage-gated sodium channel NaV 1.5 is expressed in human jejunum and colon. Mutations in NaV 1.5 are associated with gastrointestinal motility disorders. The rat gastrointestinal tract expresses voltage-gated sodium channels, but their molecular identity and role in rat gastrointestinal electrophysiology are unknown. METHODS The presence and distribution of Scn5a-encoded NaV 1.5 was examined by PCR, Western blotting and immunohistochemistry in rat jejunum. Freshly dissociated smooth muscle cells were examined by whole cell electrophysiology. Zinc finger nuclease was used to target Scn5a in rats. Lentiviral-mediated transduction with shRNA was used to target Scn5a in rat jejunum smooth muscle organotypic cultures. Organotypic cultures were examined by sharp electrode electrophysiology and RT-PCR. KEY RESULTS We found NaV 1.5 in rat jejunum and colon smooth muscle by Western blot. Immunohistochemistry using two other antibodies of different portions of NaV 1.5 revealed the presence of the ion channel in rat jejunum. Whole cell voltage-clamp in dissociated smooth muscle cells from rat jejunum showed fast activating and inactivating voltage-dependent inward current that was eliminated by Na(+) replacement by NMDG(+) . Constitutive rat Scn5a knockout resulted in death in utero. NaV 1.5 shRNA delivered by lentivirus into rat jejunum smooth muscle organotypic culture resulted in 57% loss of Scn5a mRNA and several significant changes in slow waves, namely 40% decrease in peak amplitude, 30% decrease in half-width, and 7 mV hyperpolarization of the membrane potential at peak amplitude. CONCLUSIONS & INFERENCES Scn5a-encoded NaV 1.5 is expressed in rat gastrointestinal smooth muscle and it contributes to smooth muscle electrophysiology.
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Affiliation(s)
- A Beyder
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - S J Gibbons
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - A Mazzone
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - P R Strege
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - S A Saravanaperumal
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - L Sha
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - S Higgins
- College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - S T Eisenman
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - C E Bernard
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - A Geurts
- Human and Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - C F Kline
- The Dorothy M. Davis Heart and Lung Research Institute and Departments of Physiology & Cell Biology and Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - P J Mohler
- The Dorothy M. Davis Heart and Lung Research Institute and Departments of Physiology & Cell Biology and Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - G Farrugia
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
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Radulovic M, Anand P, Korsten MA, Gong B. Targeting Ion Channels: An Important Therapeutic Implication in Gastrointestinal Dysmotility in Patients With Spinal Cord Injury. J Neurogastroenterol Motil 2015; 21:494-502. [PMID: 26424038 PMCID: PMC4622131 DOI: 10.5056/jnm15061] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Revised: 06/10/2015] [Accepted: 07/06/2015] [Indexed: 01/04/2023] Open
Abstract
Gastrointestinal (GI) dysmotility is a severe, and common complication in patients with spinal cord injury (SCI). Current therapeutic methods using acetylcholine analogs or laxative agents have unwanted side effects, besides often fail to have desired effect. Various ion channels such as ATP-sensitive potassium (KATP) channel, calcium ions (Ca2+)-activated potassium ions (K+) channels, voltage-sensitive Ca2+ channels and chloride ion (Cl−) channels are abundantly expressed in GI tissues, and play an important role in regulating GI motility. The release of neurotransmitters from the enteric nerve terminal, innervating GI interstitial cells of Cajal (ICC), and smooth muscle cells (SMC), causes inactivation of K+ and Cl− channels, increasing Ca2+ influx into cytoplasm, resulting in membrane depolarization and smooth muscle contraction. Thus, agents directly regulating ion channels activity either in ICC or in SMC may affect GI peristalsis and would be potential therapeutic target for the treatment of GI dysmotility with SCI.
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Affiliation(s)
- Miroslav Radulovic
- Department of Medicine Icahn School of Medicine at Mount Sinai, New York, NY, USA.,National Center of Excellence for the Medical Consequences of SCI, James J Peters Veteran Affairs Medical Center, Bronx, NY, USA
| | - Preeti Anand
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Mark A Korsten
- Department of Medicine Icahn School of Medicine at Mount Sinai, New York, NY, USA.,National Center of Excellence for the Medical Consequences of SCI, James J Peters Veteran Affairs Medical Center, Bronx, NY, USA
| | - Bing Gong
- Department of Medicine Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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SCN5A variant that blocks fibroblast growth factor homologous factor regulation causes human arrhythmia. Proc Natl Acad Sci U S A 2015; 112:12528-33. [PMID: 26392562 DOI: 10.1073/pnas.1516430112] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nav channels are essential for metazoan membrane depolarization, and Nav channel dysfunction is directly linked with epilepsy, ataxia, pain, arrhythmia, myotonia, and irritable bowel syndrome. Human Nav channelopathies are primarily caused by variants that directly affect Nav channel permeability or gating. However, a new class of human Nav channelopathies has emerged based on channel variants that alter regulation by intracellular signaling or cytoskeletal proteins. Fibroblast growth factor homologous factors (FHFs) are a family of intracellular signaling proteins linked with Nav channel regulation in neurons and myocytes. However, to date, there is surprisingly little evidence linking Nav channel gene variants with FHFs and human disease. Here, we provide, to our knowledge, the first evidence that mutations in SCN5A (encodes primary cardiac Nav channel Nav1.5) that alter FHF binding result in human cardiovascular disease. We describe a five*generation kindred with a history of atrial and ventricular arrhythmias, cardiac arrest, and sudden cardiac death. Affected family members harbor a novel SCN5A variant resulting in p.H1849R. p.H1849R is localized in the central binding core on Nav1.5 for FHFs. Consistent with these data, Nav1.5 p.H1849R affected interaction with FHFs. Further, electrophysiological analysis identified Nav1.5 p.H1849R as a gain-of-function for INa by altering steady-state inactivation and slowing the rate of Nav1.5 inactivation. In line with these data and consistent with human cardiac phenotypes, myocytes expressing Nav1.5 p.H1849R displayed prolonged action potential duration and arrhythmogenic afterdepolarizations. Together, these findings identify a previously unexplored mechanism for human Nav channelopathy based on altered Nav1.5 association with FHF proteins.
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Neshatian L, Strege PR, Rhee PL, Kraichely RE, Mazzone A, Bernard CE, Cima RR, Larson DW, Dozois EJ, Kline CF, Mohler PJ, Beyder A, Farrugia G. Ranolazine inhibits voltage-gated mechanosensitive sodium channels in human colon circular smooth muscle cells. Am J Physiol Gastrointest Liver Physiol 2015; 309:G506-12. [PMID: 26185330 PMCID: PMC4572410 DOI: 10.1152/ajpgi.00051.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 07/09/2015] [Indexed: 01/31/2023]
Abstract
Human jejunum smooth muscle cells (SMCs) and interstitial cells of Cajal (ICCs) express the SCN5A-encoded voltage-gated, mechanosensitive sodium channel NaV1.5. NaV1.5 contributes to small bowel excitability, and NaV1.5 inhibitor ranolazine produces constipation by an unknown mechanism. We aimed to determine the presence and molecular identity of Na(+) current in the human colon smooth muscle and to examine the effects of ranolazine on Na(+) current, mechanosensitivity, and smooth muscle contractility. Inward currents were recorded by whole cell voltage clamp from freshly dissociated human colon SMCs at rest and with shear stress. SCN5A mRNA and NaV1.5 protein were examined by RT-PCR and Western blots, respectively. Ascending human colon strip contractility was examined in a muscle bath preparation. SCN5A mRNA and NaV1.5 protein were identified in human colon circular muscle. Freshly dissociated human colon SMCs had Na(+) currents (-1.36 ± 0.36 pA/pF), shear stress increased Na(+) peaks by 17.8 ± 1.8% and accelerated the time to peak activation by 0.7 ± 0.3 ms. Ranolazine (50 μM) blocked peak Na(+) current by 43.2 ± 9.3% and inhibited shear sensitivity by 25.2 ± 3.2%. In human ascending colon strips, ranolazine decreased resting tension (31%), reduced the frequency of spontaneous events (68%), and decreased the response to smooth muscle electrical field stimulation (61%). In conclusion, SCN5A-encoded NaV1.5 is found in human colonic circular smooth muscle. Ranolazine blocks both peak amplitude and mechanosensitivity of Na(+) current in human colon SMCs and decreases contractility of human colon muscle strips. Our data provide a likely mechanistic explanation for constipation induced by ranolazine.
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Affiliation(s)
- Leila Neshatian
- 1Enteric NeuroScience Program, Mayo Clinic College of Medicine, Rochester, Minnesota; ,2Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota;
| | - Peter R. Strege
- 1Enteric NeuroScience Program, Mayo Clinic College of Medicine, Rochester, Minnesota; ,2Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota;
| | - Poong-Lyul Rhee
- 4Division of Gastroenterology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; and
| | - Robert E. Kraichely
- 1Enteric NeuroScience Program, Mayo Clinic College of Medicine, Rochester, Minnesota; ,2Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota;
| | - Amelia Mazzone
- 1Enteric NeuroScience Program, Mayo Clinic College of Medicine, Rochester, Minnesota; ,2Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota;
| | - Cheryl E. Bernard
- 1Enteric NeuroScience Program, Mayo Clinic College of Medicine, Rochester, Minnesota; ,2Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota;
| | - Robert R. Cima
- 3Department of Colon and Rectal Surgery, Mayo Clinic College of Medicine, Rochester, Minnesota;
| | - David W. Larson
- 3Department of Colon and Rectal Surgery, Mayo Clinic College of Medicine, Rochester, Minnesota;
| | - Eric J. Dozois
- 3Department of Colon and Rectal Surgery, Mayo Clinic College of Medicine, Rochester, Minnesota;
| | - Crystal F. Kline
- 5The Dorothy M. Davis Heart and Lung Research Institute and Departments of Internal Medicine and Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Peter J. Mohler
- 5The Dorothy M. Davis Heart and Lung Research Institute and Departments of Internal Medicine and Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Arthur Beyder
- 1Enteric NeuroScience Program, Mayo Clinic College of Medicine, Rochester, Minnesota; ,2Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota;
| | - Gianrico Farrugia
- Enteric NeuroScience Program, Mayo Clinic College of Medicine, Rochester, Minnesota; Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota;
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Verstraelen TE, Ter Bekke RMA, Volders PGA, Masclee AAM, Kruimel JW. The role of the SCN5A-encoded channelopathy in irritable bowel syndrome and other gastrointestinal disorders. Neurogastroenterol Motil 2015; 27:906-13. [PMID: 25898860 DOI: 10.1111/nmo.12569] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/17/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND Gastrointestinal functional and motility disorders, like irritable bowel syndrome (IBS), have a high prevalence in the Western population and cause significant morbidity and loss of quality of life leading to considerable costs for health care. A decade ago, it has been demonstrated that interstitial cells of Cajal and intestinal smooth muscle cells, cells important for gastrointestinal motility, express the sodium channel alpha subunit Nav 1.5. In the heart, aberrant variants in this sodium channel, encoded by SCN5A, are linked to inherited arrhythmia syndromes, like the long-QT syndrome type 3 and Brugada syndrome. Mounting data show a possible contribution of SCN5A mutants to gastrointestinal functional and motility disorders. Two percent of IBS patients harbor SCN5A mutations with electrophysiological evidence of loss- and gain-of-function. In addition, gastrointestinal symptoms are more prevalent in cardiac SCN5A-mutation positive patients. PURPOSE This review firstly describes the Nav 1.5 channel and its physiological role in ventricular cardiomyocytes and gastrointestinal cells, then we focus on the involvement of mutant Nav 1.5 in gastrointestinal functional and motility disorders. Future research might uncover novel mutation-specific treatment strategies for SCN5A-encoded gastrointestinal channelopathies.
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Affiliation(s)
- T E Verstraelen
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - R M A Ter Bekke
- Department of Cardiology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - P G A Volders
- Department of Cardiology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - A A M Masclee
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - J W Kruimel
- Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
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O'Grady G, Wang THH, Du P, Angeli T, Lammers WJEP, Cheng LK. Recent progress in gastric arrhythmia: pathophysiology, clinical significance and future horizons. Clin Exp Pharmacol Physiol 2015; 41:854-62. [PMID: 25115692 DOI: 10.1111/1440-1681.12288] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/11/2014] [Accepted: 07/14/2014] [Indexed: 01/27/2023]
Abstract
Gastric arrhythmia continues to be of uncertain diagnostic and therapeutic significance. However, recent progress has been substantial, with technical advances, theoretical insights and experimental discoveries offering new translational opportunities. The discoveries that interstitial cells of Cajal (ICC) generate slow waves and that ICC defects are associated with dysmotility have reinvigorated gastric arrhythmia research. Increasing evidence now suggests that ICC depletion and damage, network disruption and channelopathies may lead to aberrant slow wave initiation and conduction. Histological and high-resolution (HR) electrical mapping studies have now redefined the human 'gastric conduction system', providing an improved baseline for arrhythmia research. The application of HR mapping to arrhythmia has also generated important new insights into the spatiotemporal dynamics of arrhythmia onset and maintenance, resulting in the emergence of new provisional classification schemes. Meanwhile, the strong associations between gastric functional disorders and electrogastrography (EGG) abnormalities (e.g. in gastroparesis, unexplained nausea and vomiting and functional dyspepsia) continue to motivate deeper inquiries into the nature and causes of gastrointestinal arrhythmias. In future, technical progress in EGG methods, new HR mapping devices and software, wireless slow wave acquisition systems and improved gastric pacing devices may achieve validated applications in clinical practice. Neurohormonal factors in arrhythmogenesis also continue to be elucidated and a deepening understanding of these mechanisms may open opportunities for drug design for treating arrhythmias. However, for all translational goals, it remains to be seen whether arrhythmia can be corrected in a way that meaningfully improves organ function and symptoms in patients.
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Affiliation(s)
- Gregory O'Grady
- Department of Surgery, The University of Auckland, Auckland, New Zealand; Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
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