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Adle-Biassette H, Ricci R, Martin A, Martini M, Ravegnini G, Kaci R, Gélébart P, Poirot B, Sándor Z, Lehman-Che J, Tóth E, Papp B. Sarco/endoplasmic reticulum calcium ATPase 3 (SERCA3) expression in gastrointestinal stromal tumours. Pathology 2024; 56:343-356. [PMID: 38184384 DOI: 10.1016/j.pathol.2023.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 10/18/2023] [Indexed: 01/08/2024]
Abstract
Accurate characterisation of gastrointestinal stromal tumours (GIST) is important for prognosis and the choice of targeted therapies. Histologically the diagnosis relies on positive immunostaining of tumours for KIT (CD117) and DOG1. Here we report that GISTs also abundantly express the type 3 Sarco/Endoplasmic Reticulum Calcium ATPase (SERCA3). SERCA enzymes transport calcium ions from the cytosol into the endoplasmic reticulum and play an important role in regulating the intensity and the periodicity of calcium-induced cell activation. GISTs from various localisations, histological and molecular subtypes or risk categories were intensely immunopositive for SERCA3 with the exception of PDGFRA-mutated cases where expression was high or moderate. Strong SERCA3 expression was observed also in normal and hyperplastic interstitial cells of Cajal. Decreased SERCA3 expression in GIST was exceptionally observed in a zonal pattern, where CD117 staining was similarly decreased, reflecting clonal heterogeneity. In contrast to GIST, SERCA3 immunostaining of spindle cell tumours and other gastrointestinal tumours resembling GIST was negative or weak. In conclusion, SERCA3 immunohistochemistry may be useful for the diagnosis of GIST with high confidence, when used as a third marker in parallel with KIT and DOG1. Moreover, SERCA3 immunopositivity may be particularly helpful in cases with negative or weak KIT or DOG1 staining, a situation that may be encountered de novo, or during the spontaneous or therapy-induced clonal evolution of GIST.
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Affiliation(s)
- Homa Adle-Biassette
- Service d'Anatomie et Cytologie Pathologiques, Hôpital Lariboisière, and Assistance Publique-Hôpitaux de Paris, Université de Paris, Paris, France; INSERM NeuroDiderot, DMU DREAM, France
| | - Riccardo Ricci
- Department of Pathology, Università Cattolica del Sacro Cuore, Rome, Italy; UOC di Anatomia Patologica, Fondazione Policlinico Universitario 'A. Gemelli' IRCCS, Rome, Italy
| | - Antoine Martin
- Service d'Anatomie et Cytologie Pathologiques, Hôpital Avicenne, Assistance Publique-Hôpitaux de Paris, Paris, France; Inserm UMR U978, Université Sorbonne Paris Nord, Alliance Sorbonne Paris Cité, Labex Inflamex, Bobigny, France
| | - Maurizio Martini
- Dipartimento di patologia umana dell'adulto e dell'età evolutiva 'Gaetano Barresi' Azienda Ospedaliera Universitaria Policlinico 'G. Martino', Messina, Italy
| | - Gloria Ravegnini
- Department of Pharmacy and Biotechnology (FaBit), University of Bologna, Bologna, Italy
| | - Rachid Kaci
- Service d'Anatomie et Cytologie Pathologiques, Hôpital Lariboisière, and Assistance Publique-Hôpitaux de Paris, Université de Paris, Paris, France
| | - Pascal Gélébart
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Brigitte Poirot
- Molecular Oncology Unit, Hôpital Saint-Louis, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Zsuzsanna Sándor
- Department of Pathology, National Institute of Oncology, Budapest, Hungary
| | - Jacqueline Lehman-Che
- Molecular Oncology Unit, Hôpital Saint-Louis, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM UMR U976, Hôpital Saint-Louis, Paris, France; Institut de Recherche Saint-Louis, Université de Paris, France
| | - Erika Tóth
- Department of Pathology, National Institute of Oncology, Budapest, Hungary
| | - Bela Papp
- INSERM UMR U976, Hôpital Saint-Louis, Paris, France; Institut de Recherche Saint-Louis, Université de Paris, France; CEA, DRF-Institut Francois Jacob, Department of Hemato-Immunology Research, Hôpital Saint-Louis, Paris, France.
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Sanders KM, Drumm BT, Cobine CA, Baker SA. Ca 2+ dynamics in interstitial cells: foundational mechanisms for the motor patterns in the gastrointestinal tract. Physiol Rev 2024; 104:329-398. [PMID: 37561138 DOI: 10.1152/physrev.00036.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 06/29/2023] [Accepted: 08/06/2023] [Indexed: 08/11/2023] Open
Abstract
The gastrointestinal (GI) tract displays multiple motor patterns that move nutrients and wastes through the body. Smooth muscle cells (SMCs) provide the forces necessary for GI motility, but interstitial cells, electrically coupled to SMCs, tune SMC excitability, transduce inputs from enteric motor neurons, and generate pacemaker activity that underlies major motor patterns, such as peristalsis and segmentation. The interstitial cells regulating SMCs are interstitial cells of Cajal (ICC) and PDGF receptor (PDGFR)α+ cells. Together these cells form the SIP syncytium. ICC and PDGFRα+ cells express signature Ca2+-dependent conductances: ICC express Ca2+-activated Cl- channels, encoded by Ano1, that generate inward current, and PDGFRα+ cells express Ca2+-activated K+ channels, encoded by Kcnn3, that generate outward current. The open probabilities of interstitial cell conductances are controlled by Ca2+ release from the endoplasmic reticulum. The resulting Ca2+ transients occur spontaneously in a stochastic manner. Ca2+ transients in ICC induce spontaneous transient inward currents and spontaneous transient depolarizations (STDs). Neurotransmission increases or decreases Ca2+ transients, and the resulting depolarizing or hyperpolarizing responses conduct to other cells in the SIP syncytium. In pacemaker ICC, STDs activate voltage-dependent Ca2+ influx, which initiates a cluster of Ca2+ transients and sustains activation of ANO1 channels and depolarization during slow waves. Regulation of GI motility has traditionally been described as neurogenic and myogenic. Recent advances in understanding Ca2+ handling mechanisms in interstitial cells and how these mechanisms influence motor patterns of the GI tract suggest that the term "myogenic" should be replaced by the term "SIPgenic," as this review discusses.
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Affiliation(s)
- Kenton M Sanders
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada-Reno, Reno, Nevada, United States
| | - Bernard T Drumm
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Caroline A Cobine
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Salah A Baker
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada-Reno, Reno, Nevada, United States
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Zawieja SD, Pea GA, Broyhill SE, Bromert KH, Norton CE, Kim HJ, Li M, Castorena-Gonzalez JA, Drumm BT, Davis MJ. Lymphatic muscle cells are the innate pacemaker cells regulating mouse lymphatic collecting vessel contractions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.24.554619. [PMID: 37662284 PMCID: PMC10473772 DOI: 10.1101/2023.08.24.554619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Collecting lymphatic vessels (cLVs) exhibit spontaneous contractions with a pressure-dependent frequency, but the identity of the lymphatic pacemaker cell is still debated. By analogy to pacemakers in the GI and lower urinary tracts, proposed cLV pacemaker cells include interstitial cells of Cajal like cells (ICLC), pericytes, as well as the lymphatic muscle (LMCs) cells themselves. Here we tested the extent to which these cell types are invested into the mouse cLV wall and if any cell type exhibited morphological and functional processes characteristic of pacemaker cells: a contiguous network; spontaneous Ca2+ transients; and depolarization-induced propagated contractions. We employed inducible Cre (iCre) mouse models routinely used to target these specific cell populations including: c-kitCreERT2 to target ICLC; PdgfrβCreERT2 to target pericytes; PdgfrαCreER™ to target CD34+ adventitial fibroblast-like cells or ICLC; and Myh11CreERT2 to target LMCs. These specific inducible Cre lines were crossed to the fluorescent reporter ROSA26mT/mG, the genetically encoded Ca2+ sensor GCaMP6f, and the light-activated cation channel rhodopsin2 (ChR2). c-KitCreERT2 labeled both a sparse population of LECs and round adventitial cells that responded to the mast cell activator compound 48-80. PdgfrβCreERT2 drove recombination in both adventitial cells and LMCs, limiting its power to discriminate a pericyte specific population. PdgfrαCreER™ labeled a large population of interconnected, oak leaf-shaped cells primarily along the adventitial surface of the vessel. Titrated induction of the smooth muscle-specific Myh11CreERT2 revealed a LMC population with heterogeneous morphology. Only LMCs consistently, but heterogeneously, displayed spontaneous Ca2+ events during the diastolic period of the contraction cycle, and whose frequency was modulated in a pressure-dependent manner. Optogenetic depolarization through the expression of ChR2 by Myh11CreERT2, but not PdgfrαCreER™ or c-KitCreERT2, resulted in a propagated contraction. These findings support the conclusion that LMCs, or a subset of LMCs, are responsible for mouse cLV pacemaking.
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Affiliation(s)
- S D Zawieja
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - G A Pea
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - S E Broyhill
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - K H Bromert
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - C E Norton
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - H J Kim
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - M Li
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | | | - B T Drumm
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, A91 K584, Ireland
| | - M J Davis
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
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4
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Hwang SJ, Drumm BT, Kim MK, Lyu JH, Baker S, Sanders KM, Ward SM. Calcium transients in intramuscular interstitial cells of Cajal of the murine gastric fundus and their regulation by neuroeffector transmission. J Physiol 2022; 600:4439-4463. [PMID: 36057845 DOI: 10.1113/jp282876] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/15/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The cells responsible for mediating enteric neuroeffector transmission remain controversial. In the stomach intramuscular interstitial cells of Cajal (ICC-IM) were the first ICC reported to receive cholinergic and nitrergic neural inputs. Utilization of a cell specific calcium biosensor, GCaMP6f, the activity and neuroeffector responses of ICC-IM were examined. ICC-IM were highly active, generating stochastic intracellular Ca2+ -transients. Stimulation of enteric motor nerves abolished Ca2+ -transients in ICC-IM. This inhibitory response was preceded by a global rise in intracellular Ca2+ . Individual ICC-IM responded to nerve stimulation with a rise in Ca2+ followed by inhibition of Ca2+ -transients. Inhibition of Ca2+ -transients was blocked by the nitric oxide synthase antagonist, L-NNA. The global rise in Ca2+ was inhibited by the muscarinic antagonist, atropine. Simultaneous intracellular recordings with video imaging revealed that the global rise in intracellular Ca2+ and inhibition of Ca2+ -transients was temporally associated with rapid excitatory junction potentials followed by more sustained inhibitory junction potentials. The data presented support the premise of serial innervation of ICC-IM in excitatory and inhibitory neuroeffector transmission in the proximal stomach. ABSTRACT Enteric neurotransmission is critical for coordinating motility throughout the gastrointestinal (GI) tract. However, there is considerable controversy regarding the cells that are responsible for the transduction of these neural inputs. In the present study, utilization of a cell-specific calcium biosensor GCaMP6f, the spontaneous activity and neuroeffector responses of intramuscular ICC (ICC-IM) to motor neural inputs was examined. Simultaneous intracellular microelectrode recordings and high-speed video-imaging during nerve stimulation was used to reveal the temporal relationship between changes in intracellular Ca2+ and post-junctional electrical responses to neural stimulation. ICC-IM were highly active, generating intracellular Ca2+ -transients that occurred stochastically, from multiple independent sites in single ICC-IM. Ca2+ -transients were not entrained in single ICC-IM or between neighboring ICC-IM. Activation of enteric motor neurons produced a dominant inhibitory response that abolished Ca2+ -transients in ICC-IM. This inhibitory response was often preceded by a summation of Ca2+ -transients that led to a global rise in Ca2+ . Individual ICC-IM responded to nerve stimulation by a global rise in Ca2+ followed by inhibition of Ca2+ -transients. The inhibition of Ca2+ -transients was blocked by the nitric oxide synthase antagonist, L-NNA. The global rise in intracellular Ca2+ was inhibited by the muscarinic antagonist, atropine. Simultaneous intracellular microelectrode recordings with video-imaging revealed that the rise in Ca2+ was temporally associated with rapid excitatory junction potentials and the inhibition of Ca2+ -transients with inhibitory junction potentials. These data support the premise of serial innervation of ICC-IM in excitatory and inhibitory neuroeffector transmission in the proximal stomach. Abstract figure legend Intramuscular interstitial cells of Cajal (ICC-IM) of the gastric fundus receive nitrergic inhibitory and cholinergic excitatory neuroeffector motor inputs. Using a genetically encoded calcium sensor we demonstrate that ICC-IM are highly active cells generating stochastic intracellular Ca2 -transients. Stimulation of enteric motor nerves abolished Ca2 -transients in ICC-IM, produced an inhibitory junction potential (IJP) and muscle relaxation that was mediated by nitric oxide (left hand side of figure). This inhibitory response was often preceded by a global rise in intracellular Ca2 in ICC-IM, a rapid excitatory junction potential (EJP) and muscle contraction, that was mediated by acetylcholine (right hand side of figure). Individual ICC-IM could respond to both excitatory and inhibitory neural inputs. These data support the premise of serial innervation of ICC-IM in excitatory and inhibitory neuroeffector transmission in the proximal stomach. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Sung Jin Hwang
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Bernard T Drumm
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Min Kyung Kim
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Ju Hyeong Lyu
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Sal Baker
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Kenton M Sanders
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Sean M Ward
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, 89557, USA
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Drumm BT, Cobine CA, Baker SA. Insights on gastrointestinal motility through the use of optogenetic sensors and actuators. J Physiol 2022; 600:3031-3052. [PMID: 35596741 DOI: 10.1113/jp281930] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/13/2022] [Indexed: 11/08/2022] Open
Abstract
The muscularis of the gastrointestinal (GI) tract consists of smooth muscle cells (SMCs) and various populations of interstitial cells of Cajal (ICC), platelet-derived growth factor receptor α+ (PDGFRα+ ) cells, as well as excitatory and inhibitory enteric motor nerves. SMCs, ICC and PDGFRα+ cells form an electrically coupled syncytium, which together with inputs from the enteric nervous system (ENS) regulate GI motility. Early studies evaluating Ca2+ signalling behaviours in the GI tract relied upon indiscriminate loading of tissues with Ca2+ dyes. These methods lacked the means to study activity in specific cells of interest without encountering contamination from other cells within the preparation. Development of mice expressing optogenetic sensors (GCaMP, RCaMP) has allowed visualization of Ca2+ signalling behaviours in a cell specific manner. Additionally, availability of mice expressing optogenetic modulators (channelrhodopsins or halorhodospins) has allowed manipulation of specific signalling pathways using light. GCaMP expressing animals have been used to characterize Ca2+ signalling behaviours of distinct classes of ICC and SMCs throughout the GI musculature. These findings illustrate how Ca2+ signalling in ICC is fundamental in GI muscles, contributing to tone in sphincters, pacemaker activity in rhythmic muscles and relaying enteric signals to SMCs. Animals that express channelrhodopsin in specific neuronal populations have been used to map neural circuitry and to examine post junctional neural effects on GI motility. Thus, optogenetic approaches provide a novel means to examine the contribution of specific cell types to the regulation of motility patterns within complex multi-cellular systems. Abstract Figure Legends Optogenetic activators and sensors can be used to investigate the complex multi-cellular nature of the gastrointestinal (GI tract). Optogenetic activators that are activated by light such as channelrhodopsins (ChR2), OptoXR and halorhodopsinss (HR) proteins can be genetically encoded into specific cell types. This can be used to directly activate or silence specific GI cells such as various classes of enteric neurons, smooth muscle cells (SMC) or interstitial cells, such as interstitial cells of Cajal (ICC). Optogenetic sensors that are activated by different wavelengths of light such as green calmodulin fusion protein (GCaMP) and red CaMP (RCaMP) make high resolution of sub-cellular Ca2+ signalling possible within intact tissues of specific cell types. These tools can provide unparalleled insight into mechanisms underlying GI motility and innervation. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Bernard T Drumm
- Smooth Muscle Research Centre, Department of Life & Health Science, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland.,Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Caroline A Cobine
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Salah A Baker
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
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New open-source software for subcellular segmentation and analysis of spatiotemporal fluorescence signals using deep learning. iScience 2022; 25:104277. [PMID: 35573197 PMCID: PMC9095751 DOI: 10.1016/j.isci.2022.104277] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 04/04/2022] [Accepted: 04/18/2022] [Indexed: 11/20/2022] Open
Abstract
Cellular imaging instrumentation advancements as well as readily available optogenetic and fluorescence sensors have yielded a profound need for fast, accurate, and standardized analysis. Deep-learning architectures have revolutionized the field of biomedical image analysis and have achieved state-of-the-art accuracy. Despite these advancements, deep learning architectures for the segmentation of subcellular fluorescence signals is lacking. Cellular dynamic fluorescence signals can be plotted and visualized using spatiotemporal maps (STMaps), and currently their segmentation and quantification are hindered by slow workflow speed and lack of accuracy, especially for large datasets. In this study, we provide a software tool that utilizes a deep-learning methodology to fundamentally overcome signal segmentation challenges. The software framework demonstrates highly optimized and accurate calcium signal segmentation and provides a fast analysis pipeline that can accommodate different patterns of signals across multiple cell types. The software allows seamless data accessibility, quantification, and graphical visualization and enables large dataset analysis throughput. 4SM: an automated software solution for cellular dynamic fluorescence signal analysis 4SM relies on a novel machine-learning pipeline for fluorescence signal segmentation 4SM is fast and provides a consistent method for high-throughput analysis of datasets 4SM provides instant signal quantification and graphical representation of the results
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Drumm BT, Hannigan KI, Lee JY, Rembetski BE, Baker SA, Koh SD, Cobine CA, Sanders KM. Ca 2+ signalling in interstitial cells of Cajal contributes to generation and maintenance of tone in mouse and monkey lower esophageal sphincters. J Physiol 2022; 600:2613-2636. [PMID: 35229888 DOI: 10.1113/jp282570] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/15/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The lower esophageal sphincter (LES) generates contractile tone preventing reflux of gastric contents into the esophagus. LES smooth muscle cells (SMCs) display depolarized membrane potentials facilitating activation of L-type Ca2+ channels. Interstitial cells of Cajal (ICC) express Ca2+ -activated Cl- channels encoded by Ano1 in mouse and monkey LES. Ca2+ signaling in ICC activates ANO1 currents in ICC. ICC displayed spontaneous Ca2+ transients in mice from multiple firing sites in each cell and no entrainment of Ca2+ firing between sites or between cells. Inhibition of ANO1 channels with a specific antagonist caused hyperpolarization of mouse LES and inhibition of tone in monkey and mouse LES muscles. Our data suggest a novel mechanism for LES tone in which Ca2+ transient activation of ANO1 channels in ICC generates depolarizing inward currents that conduct to SMCs to activate L-type Ca2+ currents, Ca2+ entry and contractile tone. ABSTRACT The lower esophageal sphincter (LES) generates tone and prevents reflux of gastric contents. LES smooth muscle cells (SMCs) are relatively depolarized, facilitating activation of Cav 1.2 channels to sustain contractile tone. We hypothesised that intramuscular interstitial cells of Cajal (ICC-IM), through activation of Ca2+ -activated-Cl- channels (ANO1), set membrane potentials of SMCs favorable for activation of Cav 1.2 channels. In some gastrointestinal muscles, ANO1 channels in ICC-IM are activated by Ca2+ transients, but no studies have examined Ca2+ dynamics in ICC-IM within the LES. Immunohistochemistry and qPCR were used to determine expression of key proteins and genes in ICC-IM and SMCs. These studies revealed that Ano1 and its gene product, ANO1 are expressed in c-Kit+ cells (ICC-IM) in mouse and monkey LES clasp muscles. Ca2+ signaling was imaged in situ, using mice expressing GCaMP6f specifically in ICC (Kit-KI-GCaMP6f). ICC-IM exhibited spontaneous Ca2+ transients from multiple firing sites. Ca2+ transients were abolished by CPA or caffeine but were unaffected by tetracaine or nifedipine. Maintenance of Ca2+ transients depended on Ca2+ influx and store reloading, as Ca2+ transient frequency was reduced in Ca2+ free solution or by Orai antagonist. Spontaneous tone of LES muscles from mouse and monkey was reduced ∼80% either by Ani9, an ANO1 antagonist or by the Cav 1.2 channel antagonist nifedipine. Membrane hyperpolarisation occurred in the presence of Ani9. These data suggest that intracellular Ca2+ activates ANO1 channels in ICC-IM in the LES. Coupling of ICC-IM to SMCs drives depolarization, activation of Cav 1.2 channels, Ca2+ entry and contractile tone. Abstract figure legend Proposed mechanism for generation of contractile tone in the lower esophageal sphincter (LES). Interstitial cells of Cajal (ICC) in the LES generate spontaneous, stochastic Ca2+ transients via Ca2+ release from the endoplasmic reticulum (ER). The Ca2+ transients activate ANO1 Cl- channels causing Cl- efflux (inward current). ANO1 currents have a depolarizing effect on ICC (+++s inside membrane) and this conducts through gap junctions (GJ) to smooth muscle cells (SMCs). Input from thousands of ICC results in depolarized membrane potentials (-40 to -50 mV) which is within the window current range for L-type Ca2+ channels. Activation of these channels causes Ca2+ influx, activation of contractile elements (CE) and development of tonic contraction. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Bernard T Drumm
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA.,Smooth Muscle Research Centre, Dundalk Institute of Technology, Ireland
| | - Karen I Hannigan
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Ji Yeon Lee
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Benjamin E Rembetski
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Salah A Baker
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Sang Don Koh
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Caroline A Cobine
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Kenton M Sanders
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
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Sanders KM, Baker SA, Drumm BT, Kurahashi M. Ca 2+ Signaling Is the Basis for Pacemaker Activity and Neurotransduction in Interstitial Cells of the GI Tract. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1383:229-241. [PMID: 36587162 DOI: 10.1007/978-3-031-05843-1_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Years ago gastrointestinal motility was thought to be due to interactions between enteric nerves and smooth muscle cells (SMCs) in the tunica muscularis. Thus, regulatory mechanisms controlling motility were either myogenic or neurogenic. Now we know that populations of interstitial cells, c-Kit+ (interstitial cells of Cajal or ICC), and PDGFRα+ cells (formerly "fibroblast-like" cells) are electrically coupled to SMCs, forming the SIP syncytium. Pacemaker and neurotransduction functions are provided by interstitial cells through Ca2+ release from the endoplasmic reticulum (ER) and activation of Ca2+-activated ion channels in the plasma membrane (PM). ICC express Ca2+-activated Cl- channels encoded by Ano1. When activated, Ano1 channels produce inward current and, therefore, depolarizing or excitatory effects in the SIP syncytium. PDGFRα+ cells express Ca2+-activated K+ channels encoded by Kcnn3. These channels generate outward current when activated and hyperpolarizing or membrane-stabilizing effects in the SIP syncytium. Inputs from enteric and sympathetic neurons regulate Ca2+ transients in ICC and PDGFRα+ cells, and currents activated in these cells conduct to SMCs and regulate contractile behaviors. ICC also serve as pacemakers, generating slow waves that are the electrophysiological basis for gastric peristalsis and intestinal segmentation. Pacemaker types of ICC express voltage-dependent Ca2+ conductances that organize Ca2+ transients, and therefore Ano1 channel openings, into clusters that define the amplitude and duration of slow waves. Ca2+ handling mechanisms are at the heart of interstitial cell function, yet little is known about what happens to Ca2+ dynamics in these cells in GI motility disorders.
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Affiliation(s)
- Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, NV, USA.
| | - Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, NV, USA
| | - Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, NV, USA
| | - Masaaki Kurahashi
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, NV, USA.,Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Iowa, Iowa, Iowa City, USA
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Gastrointestinal Dysmotility Is a Significant Feature in 2 Siblings With a Novel Inositol 1,4,5-Triphosphate Receptor 1 ( ITPR1) Missense Variant. ACG Case Rep J 2021; 8:e00676. [PMID: 34722792 PMCID: PMC8549690 DOI: 10.14309/crj.0000000000000676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 06/21/2021] [Indexed: 11/25/2022] Open
Abstract
We present 2 siblings with a novel type 1 inositol 1,4,5-triphosphate receptor (ITPR1) missense variant who exhibit gastrointestinal dysmotility (chronic constipation and gastroparesis). ITPR1 is expressed in the cerebellum and interstitial cells of Cajal. Periodic release of calcium by ITPR1 initiates pacemaker currents, resulting in smooth muscle contraction. ITPR1 mutations are known to be associated with neurologic syndromes, and these variants have not previously been associated with significant gastrointestinal manifestations in humans. Using whole-genome sequencing, in silico prediction software, biopsy samples, and manometry, the identified novel ITPR1 variant is likely pathogenic and may have neurogastroenterology implications.
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Baker SA, Hwang SJ, Blair PJ, Sireika C, Wei L, Ro S, Ward SM, Sanders KM. Ca 2+ transients in ICC-MY define the basis for the dominance of the corpus in gastric pacemaking. Cell Calcium 2021; 99:102472. [PMID: 34537580 PMCID: PMC8592010 DOI: 10.1016/j.ceca.2021.102472] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/03/2021] [Accepted: 09/05/2021] [Indexed: 12/13/2022]
Abstract
Myenteric interstitial cells of Cajal (ICC-MY) generate and actively propagate electrical slow waves in the stomach. Slow wave generation and propagation are altered in gastric motor disorders, such as gastroparesis, and the mechanism for the gradient in slow wave frequency that facilitates proximal to distal propagation of slow waves and normal gastric peristalsis is poorly understood. Slow waves depend upon Ca2+-activated Cl- channels (encoded by Ano1). We characterized Ca2+ signaling in ICC-MY in situ using mice engineered to have cell-specific expression of GCaMP6f in ICC. Ca2+ signaling differed in ICC-MY in corpus and antrum. Localized Ca2+ transients were generated from multiple firing sites and were organized into Ca2+ transient clusters (CTCs). Ca2+ transient refractory periods occurred upon cessation of CTCs, but a relatively higher frequency of Ca2+ transients persisted during the inter-CTC interval in corpus than in antrum ICC-MY. The onset of Ca2+ transients after the refractory period was associated with initiation of the next CTC. Thus, CTCs were initiated at higher frequencies in corpus than in antrum ICC-MY. Initiation and propagation of CTCs (and electrical slow waves) depends upon T-type Ca2+ channels, and durations of CTCs relied upon L-type Ca2+ channels. The durations of CTCs mirrored the durations of slow waves. CTCs and Ca2+ transients between CTCs resulted from release of Ca2+ from intracellular stores and were maintained, in part, by store-operated Ca2+ entry. Our data suggest that Ca2+ release and activation of Ano1 channels both initiate and contribute to the plateau phase of slow waves.
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Affiliation(s)
- Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557, USA.
| | - Sung Jin Hwang
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557, USA
| | - Peter J Blair
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557, USA
| | - Carlee Sireika
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557, USA
| | - Lai Wei
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557, USA
| | - Seungil Ro
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557, USA
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557, USA.
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11
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Bédécarrats A, Puygrenier L, Castro O'Byrne J, Lade Q, Simmers J, Nargeot R. Organelle calcium-derived voltage oscillations in pacemaker neurons drive the motor program for food-seeking behavior in Aplysia. eLife 2021; 10:68651. [PMID: 34190043 PMCID: PMC8263059 DOI: 10.7554/elife.68651] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/29/2021] [Indexed: 12/13/2022] Open
Abstract
The expression of motivated behaviors depends on both external and internally arising neural stimuli, yet the intrinsic releasing mechanisms for such variably occurring behaviors remain elusive. In isolated nervous system preparations of Aplysia, we have found that irregularly expressed cycles of motor output underlying food-seeking behavior arise from regular membrane potential oscillations of varying magnitude in an identified pair of interneurons (B63) in the bilateral buccal ganglia. This rhythmic signal, which is specific to the B63 cells, is generated by organelle-derived intracellular calcium fluxes that activate voltage-independent plasma membrane channels. The resulting voltage oscillation spreads throughout a subset of gap junction-coupled buccal network neurons and by triggering plateau potential-mediated bursts in B63, can initiate motor output driving food-seeking action. Thus, an atypical neuronal pacemaker mechanism, based on rhythmic intracellular calcium store release and intercellular propagation, can act as an autonomous intrinsic releaser for the occurrence of a motivated behavior.
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Affiliation(s)
| | - Laura Puygrenier
- Univ. Bordeaux, INCIA, UMR 5287, F-33076 Bordeaux, Bordeaux, France
| | | | - Quentin Lade
- Univ. Bordeaux, INCIA, UMR 5287, F-33076 Bordeaux, Bordeaux, France
| | - John Simmers
- Univ. Bordeaux, INCIA, UMR 5287, F-33076 Bordeaux, Bordeaux, France
| | - Romuald Nargeot
- Univ. Bordeaux, INCIA, UMR 5287, F-33076 Bordeaux, Bordeaux, France
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12
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Xing W, Ya-ping L, Jian-zhong C, Jian-wen Y, Hai-jiao C, Cheng-cheng Z, Yan P. Effect of electroacupuncture on calcium-activated chloride channel currents in interstitial cells of Cajal in rats with diabetic gastroparesis. JOURNAL OF ACUPUNCTURE AND TUINA SCIENCE 2021. [DOI: 10.1007/s11726-021-1222-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Gathercole JL, Grosvenor AJ, Lee E, Thomas A, Mitchell CJ, Zeng N, D'Souza RF, Ramzan F, Sharma P, Knowles SO, Roy NC, Sjödin A, Wagner KH, Milan AM, Mitchell SM, Cameron-Smith D. Analysis of Human Faecal Host Proteins: Responsiveness to 10-Week Dietary Intervention Modifying Dietary Protein Intake in Elderly Males. Front Nutr 2021; 7:595905. [PMID: 33521034 PMCID: PMC7838370 DOI: 10.3389/fnut.2020.595905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/14/2020] [Indexed: 12/15/2022] Open
Abstract
Faecal proteomics targeting biomarkers of immunity and inflammation have demonstrated clinical application for the identification of changes in gastrointestinal function. However, there are limited comprehensive analyses of the host faecal proteome and how it may be influenced by dietary factors. To examine this, the Homo sapiens post-diet proteome of older males was analysed at the completion of a 10-week dietary intervention, either meeting the minimum dietary protein recommendations (RDA; n = 9) or twice the recommended dietary allowance (2RDA, n = 10). The host faecal proteome differed markedly between individuals, with only a small subset of proteins present in ≥ 60% of subjects (14 and 44 proteins, RDA and 2RDA, respectively, with only 7 common to both groups). No differences were observed between the diet groups on the profiles of host faecal proteins. Faecal proteins were detected from a wide range of protein classes, with high inter-individual variation and absence of obvious impact in response to diets with markedly different protein intake. This suggests that well-matched whole food diets with two-fold variation in protein intake maintained for 10 weeks have minimal impact on human faecal host proteins.
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Affiliation(s)
| | - Anita J Grosvenor
- Proteins and Metabolites Team, AgResearch, Lincoln, Christchurch, New Zealand
| | - Erin Lee
- Proteins and Metabolites Team, AgResearch, Lincoln, Christchurch, New Zealand
| | - Ancy Thomas
- Proteins and Metabolites Team, AgResearch, Lincoln, Christchurch, New Zealand
| | - Cameron J Mitchell
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.,Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Nina Zeng
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Randall F D'Souza
- Liggins Institute, University of Auckland, Auckland, New Zealand.,Discipline of Nutrition, University of Auckland, Auckland, New Zealand
| | - Farha Ramzan
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Pankaja Sharma
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Scott O Knowles
- Food, Nutrition, and Health Team, AgResearch, Auckland University, Auckland, New Zealand
| | - Nicole C Roy
- Liggins Institute, University of Auckland, Auckland, New Zealand.,Food, Nutrition, and Health Team, AgResearch, Auckland University, Auckland, New Zealand.,Department of Nutrition, University of Otago, Dunedin, New Zealand.,Riddet Institute, Massey University, Palmerston North, New Zealand.,High-Value Nutrition National Science Challenge, Auckland, New Zealand
| | - Anders Sjödin
- Department of Nutrition, Exercise, and Sports, Copenhagen University, Copenhagen, Denmark
| | - Karl-Heinz Wagner
- Department of Nutritional Sciences and Research Platform Active Ageing, University of Vienna, Vienna, Austria
| | - Amber M Milan
- Liggins Institute, University of Auckland, Auckland, New Zealand.,Food, Nutrition, and Health Team, AgResearch, Auckland University, Auckland, New Zealand
| | - Sarah M Mitchell
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - David Cameron-Smith
- Liggins Institute, University of Auckland, Auckland, New Zealand.,Agency for Science, Technology, and Research, Singapore Institute for Clinical Sciences, Singapore, Singapore
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14
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Baker SA, Leigh WA, Del Valle G, De Yturriaga IF, Ward SM, Cobine CA, Drumm BT, Sanders KM. Ca 2+ signaling driving pacemaker activity in submucosal interstitial cells of Cajal in the murine colon. eLife 2021; 10:64099. [PMID: 33399536 PMCID: PMC7806270 DOI: 10.7554/elife.64099] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/04/2021] [Indexed: 02/06/2023] Open
Abstract
Interstitial cells of Cajal (ICC) generate pacemaker activity responsible for phasic contractions in colonic segmentation and peristalsis. ICC along the submucosal border (ICC-SM) contribute to mixing and more complex patterns of colonic motility. We show the complex patterns of Ca2+ signaling in ICC-SM and the relationship between ICC-SM Ca2+ transients and activation of smooth muscle cells (SMCs) using optogenetic tools. ICC-SM displayed rhythmic firing of Ca2+transients ~ 15 cpm and paced adjacent SMCs. The majority of spontaneous activity occurred in regular Ca2+ transients clusters (CTCs) that propagated through the network. CTCs were organized and dependent upon Ca2+ entry through voltage-dependent Ca2+ conductances, L- and T-type Ca2+ channels. Removal of Ca2+ from the external solution abolished CTCs. Ca2+ release mechanisms reduced the duration and amplitude of Ca2+ transients but did not block CTCs. These data reveal how colonic pacemaker ICC-SM exhibit complex Ca2+-firing patterns and drive smooth muscle activity and overall colonic contractions.
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Affiliation(s)
- Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, United States
| | - Wesley A Leigh
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, United States
| | - Guillermo Del Valle
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, United States
| | - Inigo F De Yturriaga
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, United States
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, United States
| | - Caroline A Cobine
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, United States
| | - Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, United States
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, United States
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15
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Chevalier NR, Ammouche Y, Gomis A, Teyssaire C, de Santa Barbara P, Faure S. Shifting into high gear: how interstitial cells of Cajal change the motility pattern of the developing intestine. Am J Physiol Gastrointest Liver Physiol 2020; 319:G519-G528. [PMID: 32877218 DOI: 10.1152/ajpgi.00112.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The first contractile waves in the developing embryonic gut are purely myogenic; they only involve smooth muscle. Here, we provide evidence for a transition from smooth muscle to interstitial cell of Cajal (ICC)-driven contractile waves in the developing chicken gut. In situ hybridization staining for anoctamin-1 (ANO1), a known ICC marker, shows that ICCs are already present throughout the gut, as from embryonic day (E)7. We devised a protocol to reveal ICC oscillatory and propagative calcium activity in embryonic gut whole mount and found that the first steady calcium oscillations in ICCs occur on (E14). We show that the activation of ICCs leads to an increase in contractile wave frequency, regularity, directionality, and velocity between E12 and E14. We finally demonstrate that application of the c-KIT antagonist imatinib mesylate in organ culture specifically depletes the ICC network and inhibits the transition to a regular rhythmic wave pattern. We compare our findings to existing results in the mouse and predict that a similar transition should take place in the human fetus between 12 and 14 wk of development. Together, our results point to an abrupt physiological transition from smooth muscle mesenchyme self-initiating waves to ICC-driven motility in the fetus and clarify the contribution of ICCs to the contractile wave pattern.NEW & NOTEWORTHY We reveal a sharp transition from smooth muscle to interstitial cell of Cajal (ICC)-driven motility in the chicken embryo, leading to higher-frequency, more rhythmic contractile waves. We predict the transition to happen between 12 and 14 embryonic wk in humans. We image for the first time the onset of ICC activity in an embryonic gut by calcium imaging. We show the first KIT and anoctamin-1 (ANO1) in situ hybridization micrographs in the embryonic chicken gut.
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Affiliation(s)
- Nicolas R Chevalier
- Laboratoire Matière et Systèmes Complexes, Université de Paris/CNRS UMR 7057, Sorbonne Paris Cité, 75013 Paris, France
| | - Yanis Ammouche
- Laboratoire Matière et Systèmes Complexes, Université de Paris/CNRS UMR 7057, Sorbonne Paris Cité, 75013 Paris, France
| | - Anthony Gomis
- Laboratoire Matière et Systèmes Complexes, Université de Paris/CNRS UMR 7057, Sorbonne Paris Cité, 75013 Paris, France
| | - Clémence Teyssaire
- Laboratoire Matière et Systèmes Complexes, Université de Paris/CNRS UMR 7057, Sorbonne Paris Cité, 75013 Paris, France
| | | | - Sandrine Faure
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
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16
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Johnson AC, Louwies T, Ligon CO, Greenwood-Van Meerveld B. Enlightening the frontiers of neurogastroenterology through optogenetics. Am J Physiol Gastrointest Liver Physiol 2020; 319:G391-G399. [PMID: 32755304 PMCID: PMC7717115 DOI: 10.1152/ajpgi.00384.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Neurogastroenterology refers to the study of the extrinsic and intrinsic nervous system circuits controlling the gastrointestinal (GI) tract. Over the past 5-10 yr there has been an explosion in novel methodologies, technologies and approaches that offer great promise to advance our understanding of the basic mechanisms underlying GI function in health and disease. This review focuses on the use of optogenetics combined with electrophysiology in the field of neurogastroenterology. We discuss how these technologies and tools are currently being used to explore the brain-gut axis and debate the future research potential and limitations of these techniques. Taken together, we consider that the use of these technologies will enable researchers to answer important questions in neurogastroenterology through fundamental research. The answers to those questions will shorten the path from basic discovery to new treatments for patient populations with disorders of the brain-gut axis affecting the GI tract such as irritable bowel syndrome (IBS), functional dyspepsia, achalasia, and delayed gastric emptying.
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Affiliation(s)
- Anthony C. Johnson
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma,3Department of Neurology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Tijs Louwies
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Casey O. Ligon
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Beverley Greenwood-Van Meerveld
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma,4Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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17
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Leigh WA, Del Valle G, Kamran SA, Drumm BT, Tavakkoli A, Sanders KM, Baker SA. A high throughput machine-learning driven analysis of Ca 2+ spatio-temporal maps. Cell Calcium 2020; 91:102260. [PMID: 32795721 DOI: 10.1016/j.ceca.2020.102260] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/24/2020] [Accepted: 07/24/2020] [Indexed: 12/31/2022]
Abstract
High-resolution Ca2+ imaging to study cellular Ca2+ behaviors has led to the creation of large datasets with a profound need for standardized and accurate analysis. To analyze these datasets, spatio-temporal maps (STMaps) that allow for 2D visualization of Ca2+ signals as a function of time and space are often used. Methods of STMap analysis rely on a highly arduous process of user defined segmentation and event-based data retrieval. These methods are often time consuming, lack accuracy, and are extremely variable between users. We designed a novel automated machine-learning based plugin for the analysis of Ca2+ STMaps (STMapAuto). The plugin includes optimized tools for Ca2+ signal preprocessing, automated segmentation, and automated extraction of key Ca2+ event information such as duration, spatial spread, frequency, propagation angle, and intensity in a variety of cell types including the Interstitial cells of Cajal (ICC). The plugin is fully implemented in Fiji and able to accurately detect and expeditiously quantify Ca2+ transient parameters from ICC. The plugin's speed of analysis of large-datasets was 197-fold faster than the commonly used single pixel-line method of analysis. The automated machine-learning based plugin described dramatically reduces opportunities for user error and provides a consistent method to allow high-throughput analysis of STMap datasets.
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Affiliation(s)
- Wesley A Leigh
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA
| | - Guillermo Del Valle
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA
| | - Sharif Amit Kamran
- Department of Computer Science and Engineering, University of Nevada School of Medicine, Reno, NV 89557, USA
| | - Bernard T Drumm
- Department of Life & Health Science, Dundalk Institute of Technology, Co. Louth, Ireland
| | - Alireza Tavakkoli
- Department of Computer Science and Engineering, University of Nevada School of Medicine, Reno, NV 89557, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA
| | - Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA.
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18
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Hannigan KI, Bossey AP, Foulkes HJL, Drumm BT, Baker SA, Ward SM, Sanders KM, Keef KD, Cobine CA. A novel intramuscular Interstitial Cell of Cajal is a candidate for generating pacemaker activity in the mouse internal anal sphincter. Sci Rep 2020; 10:10378. [PMID: 32587396 PMCID: PMC7316801 DOI: 10.1038/s41598-020-67142-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 06/03/2020] [Indexed: 12/14/2022] Open
Abstract
The internal anal sphincter (IAS) generates phasic contractions and tone. Slow waves (SWs) produced by interstitial cells of Cajal (ICC) underlie phasic contractions in other gastrointestinal regions. SWs are also present in the IAS where only intramuscular ICC (ICC-IM) are found, however the evidence linking ICC-IM to SWs is limited. This study examined the possible relationship between ICC-IM and SWs by recording Ca2+ transients in mice expressing a genetically-encoded Ca2+-indicator in ICC (Kit-Cre-GCaMP6f). A role for L-type Ca2+ channels (CavL) and anoctamin 1 (ANO1) was tested since each is essential for SW and tone generation. Two distinct ICC-IM populations were identified. Type I cells (36% of total) displayed localised asynchronous Ca2+ transients not dependent on CavL or ANO1; properties typical of ICC-IM mediating neural responses in other gastrointestinal regions. A second novel sub-type, i.e., Type II cells (64% of total) generated rhythmic, global Ca2+ transients at the SW frequency that were synchronised with neighbouring Type II cells and were abolished following blockade of either CavL or ANO1. Thus, the spatiotemporal characteristics of Type II cells and their dependence upon CavL and ANO1 all suggest that these cells are viable candidates for the generation of SWs and tone in the IAS.
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Affiliation(s)
- Karen I Hannigan
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Aaron P Bossey
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Holly J L Foulkes
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Kathleen D Keef
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Caroline A Cobine
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA.
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19
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Drumm BT, Rembetski BE, Huynh K, Nizar A, Baker SA, Sanders KM. Excitatory cholinergic responses in mouse colon intramuscular interstitial cells of Cajal are due to enhanced Ca 2+ release via M 3 receptor activation. FASEB J 2020; 34:10073-10095. [PMID: 32539213 DOI: 10.1096/fj.202000672r] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 05/01/2020] [Accepted: 05/11/2020] [Indexed: 12/14/2022]
Abstract
Colonic intramuscular interstitial cells of Cajal (ICC-IM) are associated with cholinergic varicosities, suggesting a role in mediating excitatory neurotransmission. Ca2+ release in ICC-IM activates Ano1, a Ca2+ -activated Cl- conductance, causing tissue depolarization and increased smooth muscle excitability. We employed Ca2+ imaging of colonic ICC-IM in situ, using mice expressing GCaMP6f in ICC to evaluate ICC-IM responses to excitatory neurotransmission. Expression of muscarinic type 2, 3 (M2 , M3 ), and NK1 receptors were enriched in ICC-IM. NK1 receptor agonists had minimal effects on ICC-IM, whereas neostigmine and carbachol increased Ca2+ transients. These effects were reversed by DAU 5884 (M3 receptor antagonist) but not AF-DX 116 (M2 receptor antagonist). Electrical field stimulation (EFS) in the presence of L-NNA and MRS 2500 enhanced ICC-IM Ca2+ transients. Responses were blocked by atropine or DAU 5884, but not AF-DX 116. ICC-IM responses to EFS were ablated by inhibiting Ca2+ stores with cyclopiazonic acid and reduced by inhibiting Ca2+ influx via Orai channels. Contractions induced by EFS were reduced by an Ano1 channel antagonist, abolished by DAU 5884, and unaffected by AF-DX 116. Colonic ICC-IM receive excitatory inputs from cholinergic neurons via M3 receptor activation. Enhancing ICC-IM Ca2+ release and Ano1 activation contributes to excitatory responses of colonic muscles.
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Affiliation(s)
- Bernard T Drumm
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA.,Department of Life & Health Science, Dundalk Institute of Technology, Dundalk, Ireland
| | - Benjamin E Rembetski
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA
| | - Kaitlin Huynh
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA
| | - Aqeel Nizar
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA
| | - Salah A Baker
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, USA
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20
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Grainger N, Freeman RS, Shonnard CC, Drumm BT, Koh SD, Ward SM, Sanders KM. Identification and classification of interstitial cells in the mouse renal pelvis. J Physiol 2020; 598:3283-3307. [PMID: 32415739 DOI: 10.1113/jp278888] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 04/29/2020] [Indexed: 12/13/2022] Open
Abstract
KEY POINTS Platelet-derived growth factor receptor-α (PDGFRα) is a novel biomarker along with smooth myosin heavy chain for the pacemaker cells (previously termed 'atypical' smooth muscle cells) in the murine and cynomolgus monkey pelvis-kidney junction. PDGFRα+ cells present in adventitial and urothelial layers of murine renal pelvis do not express smooth muscle myosin heavy chain (smMHC) but are in close apposition to nerve fibres. Most c-Kit+ cells in the renal pelvis are mast cells. Mast cells (CD117+ /CD45+ ) are more abundant in the proximal renal pelvis and pelvis-kidney junction regions whereas c-Kit+ interstitial cells (CD117+ /CD45- ) are found predominantly in the distal renal pelvis and ureteropelvic junction. PDGFRα+ cells are distinct from c-Kit+ interstitial cells. A subset of PDGFRα+ cells express the Ca2+ -activated Cl- channel, anoctamin-1, across the entire renal pelvis. Spontaneous Ca2+ transients were observed in c-Kit+ interstitial cells, smMHC+ PDGFRα cells and smMHC- PDGFRα cells using mice expressing genetically encoded Ca2+ sensors. ABSTRACT Rhythmic contractions of the renal pelvis transport urine from the kidneys into the ureter. Specialized pacemaker cells, termed atypical smooth muscle cells (ASMCs), are thought to drive the peristaltic contractions of typical smooth muscle cells (TSMCs) in the renal pelvis. Interstitial cells (ICs) in close proximity to ASMCs and TSMCs have been described, but the role of these cells is poorly understood. The presence and distributions of platelet-derived growth factor receptor-α+ (PDGFRα+ ) ICs in the pelvis-kidney junction (PKJ) and distal renal pelvis were evaluated. We found PDGFRα+ ICs in the adventitial layers of the pelvis, the muscle layer of the PKJ and the adventitia of the distal pelvis. PDGFRα+ ICs were distinct from c-Kit+ ICs in the renal pelvis. c-Kit+ ICs are a minor population of ICs in murine renal pelvis. The majority of c-Kit+ cells were mast cells. PDGFRα+ cells in the PKJ co-expressed smooth muscle myosin heavy chain (smMHC) and several other smooth muscle gene transcripts, indicating these cells are ASMCs, and PDGFRα is a novel biomarker for ASMCs. PDGFRα+ cells also express Ano1, which encodes a Ca2+ -activated Cl- conductance that serves as a primary pacemaker conductance in ICs of the GI tract. Spontaneous Ca2+ transients were observed in c-Kit+ ICs, smMHC+ PDGFRα cells and smMHC- PDGFRα cells using genetically encoded Ca2+ sensors. A reporter strain of mice with enhanced green fluorescent protein driven by the endogenous promotor for Pdgfra was shown to be a powerful new tool for isolating and characterizing the phenotype and functions of these cells in the renal pelvis.
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Affiliation(s)
- Nathan Grainger
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Ryan S Freeman
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Cameron C Shonnard
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Bernard T Drumm
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Sang Don Koh
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Sean M Ward
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Kenton M Sanders
- Department of Physiology & Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
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21
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Cobine CA, Hannigan KI, McMahon M, Bhraonain EPN, Baker SA, Keef KD. Rhythmic calcium transients in smooth muscle cells of the mouse internal anal sphincter. Neurogastroenterol Motil 2020; 32:e13746. [PMID: 31625250 PMCID: PMC7047590 DOI: 10.1111/nmo.13746] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/22/2019] [Accepted: 09/26/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND The internal anal sphincter (IAS) exhibits slow waves (SWs) and tone that are dependent upon L-type Ca2+ channels (CavL ) suggesting that phasic events (ie, SWs) play a fundamental role in tone generation. The present study further examined phasic activity in the IAS by measuring the spatiotemporal properties of Ca2+ transients (CTs) in IAS smooth muscle cells (SMCs). METHODS Ca2+ transients were recorded with spinning disk confocal microscopy from the IAS of SM-GCaMP mice. Muscles were pinned submucosal surface up at two different lengths. Drugs were applied by inclusion in the superfusate. KEY RESULTS Ca2+ transients displayed ongoing rhythmic firings at both lengths and were abolished by nifedipine and the KATP channel activator pinacidil indicating their dependence upon CavL . Like SWs, CTs were greatest in frequency (average 70.6 cpm) and amplitude at the distal extremity and conducted proximally. Removal of the distal IAS reduced but did not abolish CTs. The time constant for clearing cytoplasmic Ca2+ averaged 0.46 seconds and basal Ca2+ levels were significantly elevated. CONCLUSIONS & INFERENCES The similarities in spatiotemporal and pharmacological properties of CTs and SWs suggest that SW gives rise to CTs while muscle stretch is not required. Elevated relative basal Ca2+ in the IAS is likely due to the inability of cells to clear or sequester Ca2+ between rapid frequency voltage-dependent Ca2+ entry events, that is, conditions that will lead to tone development. The conduction of CTs from distal to proximal IAS will lead to orally directed contractions and likely contribute to the maintenance of fecal continence.
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Affiliation(s)
- Caroline A Cobine
- Corresponding Author: Caroline Cobine, Ph.D., Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, 1664 N. Virginia St., MS 352, Reno, NV 89557, USA, Phone: 1-775-682-8840, Fax: 1-775-784-6903,
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22
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Kurahashi M, Kito Y, Baker SA, Jennings LK, Dowers JGR, Koh SD, Sanders KM. A novel postsynaptic signal pathway of sympathetic neural regulation of murine colonic motility. FASEB J 2020; 34:5563-5577. [PMID: 32086857 DOI: 10.1096/fj.201903134r] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/04/2020] [Accepted: 02/13/2020] [Indexed: 01/14/2023]
Abstract
Transcriptome data revealed α1 adrenoceptors (ARs) expression in platelet-derived growth factor receptor α+ cells (PDGFRα+ cells) in murine colonic musculature. The role of PDGFRα+ cells in sympathetic neural regulation of murine colonic motility was investigated. Norepinephrine (NE), via α1A ARs, activated a small conductance Ca2+ -activated K+ (SK) conductance, evoked outward currents and hyperpolarized PDGFRα+ cells (the α1A AR-SK channel signal pathway). α1 AR agonists increased intracellular Ca2+ transients in PDGFRα+ cells and inhibited spontaneous phasic contractions (SPCs) of colonic muscle through activation of a SK conductance. Sympathetic nerve stimulation inhibited both contractions of distal colon and propulsive contractions represented by the colonic migrating motor complexes (CMMCs) via the α1A AR-SK channel signal pathway. Postsynaptic signaling through α1A ARs in PDGFRα+ cells is a novel mechanism that conveys part of stress responses in the colon. PDGFRα+ cells appear to be a primary effector of sympathetic neural regulation of murine colonic motility.
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Affiliation(s)
- Masaaki Kurahashi
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
| | - Yoshihiko Kito
- Department of Pharmacology, Saga University, Saga, Japan
| | - Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
| | - Libby K Jennings
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
| | - James G R Dowers
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
| | - Sang Don Koh
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
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23
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Parsons SP, Huizinga JD. A myogenic motor pattern in mice lacking myenteric interstitial cells of Cajal explained by a second coupled oscillator network. Am J Physiol Gastrointest Liver Physiol 2020; 318:G225-G243. [PMID: 31813235 PMCID: PMC7052571 DOI: 10.1152/ajpgi.00311.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The interstitial cells of Cajal associated with the myenteric plexus (ICC-MP) are a network of coupled oscillators in the small intestine that generate rhythmic electrical phase waves leading to corresponding waves of contraction, yet rhythmic action potentials and intercellular calcium waves have been recorded from c-kit-mutant mice that lack the ICC-MP, suggesting that there may be a second pacemaker network. The gap junction blocker carbenoxolone induced a "pinstripe" motor pattern consisting of rhythmic "stripes" of contraction that appeared simultaneously across the intestine with a period of ~4 s. The infinite velocity of these stripes suggested they were generated by a coupled oscillator network, which we call X. In c-kit mutants rhythmic contraction waves with the period of X traveled the length of the intestine, before the induction of the pinstripe pattern by carbenoxolone. Thus X is not the ICC-MP and appears to operate under physiological conditions, a fact that could explain the viability of these mice. Individual stripes consisted of a complex pattern of bands of contraction and distension, and between stripes there could be slide waves and v waves of contraction. We hypothesized that these phenomena result from an interaction between X and the circular muscle that acts as a damped oscillator. A mathematical model of two chains of coupled Fitzhugh-Nagumo systems, representing X and circular muscle, supported this hypothesis. The presence of a second coupled oscillator network in the small intestine underlines the complexity of motor pattern generation in the gut.NEW & NOTEWORTHY Physiological experiments and a mathematical model indicate a coupled oscillator network in the small intestine in addition to the c-kit-expressing myenteric interstitial cells of Cajal. This network interacts with the circular muscle, which itself acts as a system of damped oscillators, to generate physiological contraction waves in c-kit (W) mutant mice.
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Affiliation(s)
- Sean P. Parsons
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Jan D. Huizinga
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
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24
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Drumm BT, Rembetski BE, Messersmith K, Manierka MS, Baker SA, Sanders KM. Pacemaker function and neural responsiveness of subserosal interstitial cells of Cajal in the mouse colon. J Physiol 2020; 598:651-681. [PMID: 31811726 DOI: 10.1113/jp279102] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 11/22/2019] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Rhythmic action potentials and intercellular Ca2+ waves are generated in smooth muscle cells of colonic longitudinal muscles (LSMC). Longitudinal muscle excitability is tuned by input from subserosal ICC (ICC-SS), a population of ICC with previously unknown function. ICC-SS express Ano1 channels and generate spontaneous Ca2+ transients in a stochastic manner. Release of Ca2+ and activation of Ano1 channels causes depolarization of ICC-SS and LSMC, leading to activation of L-type Ca2+ channels, action potentials, intercellular Ca2+ waves and contractions in LSMC. Nitrergic neural inputs regulate the Ca2+ events in ICC-SS. Pacemaker activity in longitudinal muscle is an emergent property as a result of integrated processes in ICC-SS and LSMC. ABSTRACT Much is known about myogenic mechanisms in circular muscle (CM) in the gastrointestinal tract, although less is known about longitudinal muscle (LM). Two Ca2+ signalling behaviours occur in LM: localized intracellular waves not causing contractions and intercellular waves leading to excitation-contraction coupling. An Ano1 channel antagonist inhibited intercellular Ca2+ waves and LM contractions. Ano1 channels are expressed by interstitial cells of Cajal (ICC) but not by smooth muscle cells (SMCs). We investigated Ca2+ signalling in a novel population of ICC that lies along the subserosal surface of LM (ICC-SS) in mice expressing GCaMP6f in ICC. ICC-SS fired stochastic localized Ca2+ transients. Such events have been linked to activation of Ano1 channels in ICC. Ca2+ transients in ICC-SS occurred by release from stores most probably via inositol trisphosphate receptors. This activity relied on influx via store-operated Ca2+ entry and Orai channels. No voltage-dependent mechanism that synchronized Ca2+ transients in a single cell or between cells was found. Nitrergic agonists inhibited Ca2+ transients in ICC-SS, and stimulation of intrinsic nerves activated nitrergic responses in ICC-SS. Cessation of stimulation resulted in significant enhancement of Ca2+ transients compared to the pre-stimulus activity. No evidence of innervation by excitatory, cholinergic motor neurons was found. Our data suggest that ICC-SS contribute to regulation of LM motor activity. Spontaneous Ca2+ transients activate Ano1 channels in ICC-SS. Resulting depolarization conducts to SMCs, depolarizing membrane potential, activating L-type Ca2+ channels and initiating contraction. Rhythmic electrical and mechanical behaviours of LM are an emergent property of SMCs and ICC-SS.
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Affiliation(s)
- Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Benjamin E Rembetski
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Katelyn Messersmith
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Marena S Manierka
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
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Rude KM, Pusceddu MM, Keogh CE, Sladek JA, Rabasa G, Miller EN, Sethi S, Keil KP, Pessah IN, Lein PJ, Gareau MG. Developmental exposure to polychlorinated biphenyls (PCBs) in the maternal diet causes host-microbe defects in weanling offspring mice. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 253:708-721. [PMID: 31336350 PMCID: PMC6719698 DOI: 10.1016/j.envpol.2019.07.066] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 07/12/2019] [Accepted: 07/12/2019] [Indexed: 05/05/2023]
Abstract
The gut microbiota is important for maintaining homeostasis of the host. Gut microbes represent the initial site for toxicant processing following dietary exposures to environmental contaminants. The diet is the primary route of exposure to polychlorinated biphenyls (PCBs), which are absorbed via the gut, and subsequently interfere with neurodevelopment and behavior. Developmental exposures to PCBs have been linked to increased risk of neurodevelopmental disorders (NDD), including autism spectrum disorder (ASD), which are also associated with a high prevalence of gastrointestinal (GI) distress and intestinal dysbiosis. We hypothesized that developmental PCB exposure impacts colonization of the gut microbiota, resulting in GI pathophysiology, in a genetically susceptible host. Mouse dams expressing two heritable human mutations (double mutants [DM]) that result in abnormal Ca2+ dynamics and produce behavioral deficits (gain of function mutation in the ryanodine receptor 1 [T4826I-RYR1] and a human CGG repeat expansion [170-200 CGG repeats] in the fragile X mental retardation gene 1 [FMR1 premutation]). DM and congenic wild type (WT) controls were exposed to PCBs (0-6 mg/kg/d) in the diet starting 2 weeks before gestation and continuing through postnatal day 21 (P21). Intestinal physiology (Ussing chambers), inflammation (qPCR) and gut microbiome (16S sequencing) studies were performed in offspring mice (P28-P30). Developmental exposure to PCBs in the maternal diet caused significant mucosal barrier defects in ileum and colon (increased secretory state and tight junction permeability) of juvenile DM mice. Furthermore, PCB exposure increased the intestinal inflammatory profile (Il6, Il1β, and Il22), and resulted in dysbiosis of the gut microbiota, including altered β-diversity, in juvenile DM mice developmentally exposed to 1 mg/kg/d PCBs when compared to WT controls. Collectively, these findings demonstrate a novel interaction between PCB exposure and the gut microbiota in a genetically susceptible host that provide novel insight into environmental risk factors for neurodevelopmental disorders.
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Affiliation(s)
- Kavi M Rude
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95616, United States
| | - Matteo M Pusceddu
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95616, United States
| | - Ciara E Keogh
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95616, United States
| | - Jessica A Sladek
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95616, United States
| | - Gonzalo Rabasa
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95616, United States
| | - Elaine N Miller
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95616, United States
| | - Sunjay Sethi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95616, United States
| | - Kimberly P Keil
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95616, United States
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95616, United States
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95616, United States
| | - Mélanie G Gareau
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95616, United States.
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Drumm BT, Hwang SJ, Baker SA, Ward SM, Sanders KM. Ca 2+ signalling behaviours of intramuscular interstitial cells of Cajal in the murine colon. J Physiol 2019; 597:3587-3617. [PMID: 31124144 DOI: 10.1113/jp278036] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 05/23/2019] [Indexed: 12/13/2022] Open
Abstract
KEY POINTS Colonic intramuscular interstitial cells of Cajal (ICC-IM) exhibit spontaneous Ca2+ transients manifesting as stochastic events from multiple firing sites with propagating Ca2+ waves occasionally observed. Firing of Ca2+ transients in ICC-IM is not coordinated with adjacent ICC-IM in a field of view or even with events from other firing sites within a single cell. Ca2+ transients, through activation of Ano1 channels and generation of inward current, cause net depolarization of colonic muscles. Ca2+ transients in ICC-IM rely on Ca2+ release from the endoplasmic reticulum via IP3 receptors, spatial amplification from RyRs and ongoing refilling of ER via the sarcoplasmic/endoplasmic-reticulum-Ca2+ -ATPase. ICC-IM are sustained by voltage-independent Ca2+ influx via store-operated Ca2+ entry. Some of the properties of Ca2+ in ICC-IM in the colon are similar to the behaviour of ICC located in the deep muscular plexus region of the small intestine, suggesting there are functional similarities between these classes of ICC. ABSTRACT A component of the SIP syncytium that regulates smooth muscle excitability in the colon is the intramuscular class of interstitial cells of Cajal (ICC-IM). All classes of ICC (including ICC-IM) express Ca2+ -activated Cl- channels, encoded by Ano1, and rely upon this conductance for physiological functions. Thus, Ca2+ handling in ICC is fundamental to colonic motility. We examined Ca2+ handling mechanisms in ICC-IM of murine proximal colon expressing GCaMP6f in ICC. Several Ca2+ firing sites were detected in each cell. While individual sites displayed rhythmic Ca2+ events, the overall pattern of Ca2+ transients was stochastic. No correlation was found between discrete Ca2+ firing sites in the same cell or in adjacent cells. Ca2+ transients in some cells initiated Ca2+ waves that spread along the cell at ∼100 µm s-1 . Ca2+ transients were caused by release from intracellular stores, but depended strongly on store-operated Ca2+ entry mechanisms. ICC Ca2+ transient firing regulated the resting membrane potential of colonic tissues as a specific Ano1 antagonist hyperpolarized colonic muscles by ∼10 mV. Ca2+ transient firing was independent of membrane potential and not affected by blockade of L- or T-type Ca2+ channels. Mechanisms regulating Ca2+ transients in the proximal colon displayed both similarities to and differences from the intramuscular type of ICC in the small intestine. Similarities and differences in Ca2+ release patterns might determine how ICC respond to neurotransmission in these two regions of the gastrointestinal tract.
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Affiliation(s)
- Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, 89557, USA
| | - Sung J Hwang
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, 89557, USA
| | - Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, 89557, USA
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, 89557, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, 89557, USA
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Tonic inhibition of murine proximal colon is due to nitrergic suppression of Ca 2+ signaling in interstitial cells of Cajal. Sci Rep 2019; 9:4402. [PMID: 30867452 PMCID: PMC6416298 DOI: 10.1038/s41598-019-39729-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 01/30/2019] [Indexed: 12/18/2022] Open
Abstract
Spontaneous excitability and contractions of colonic smooth muscle cells (SMCs) are normally suppressed by inputs from inhibitory motor neurons, a behavior known as tonic inhibition. The post-junctional cell(s) mediating tonic inhibition have not been elucidated. We investigated the post-junctional cells mediating tonic inhibition in the proximal colon and whether tonic inhibition results from suppression of the activity of Ano1 channels, which are expressed exclusively in interstitial cells of Cajal (ICC). We found that tetrodotoxin (TTX), an inhibitor of nitric oxide (NO) synthesis, L-NNA, and an inhibitor of soluble guanylyl cyclase, ODQ, greatly enhanced colonic contractions. Ano1 antagonists, benzbromarone and Ani9 inhibited the effects of TTX, L-NNA and ODQ. Ano1 channels are activated by Ca2+ release from the endoplasmic reticulum (ER) in ICC, and blocking Ca2+ release with a SERCA inhibitor (thapsigargin) or a store-operated Ca2+ entry blocker (GSK 7975 A) reversed the effects of TTX, L-NNA and ODQ. Ca2+ imaging revealed that TTX, L-NNA and ODQ increased Ca2+ transient firing in colonic ICC. Our results suggest that tonic inhibition in the proximal colon occurs through suppression of Ca2+ release events in ICC. Suppression of Ca2+ release in ICC limits the open probability of Ano1 channels, reducing the excitability of electrically-coupled SMCs.
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A Noisy Analog-to-Digital Converter Connects Cytosolic Calcium Bursts to Transcription Factor Nuclear Localization Pulses in Yeast. G3-GENES GENOMES GENETICS 2019; 9:561-570. [PMID: 30573469 PMCID: PMC6385971 DOI: 10.1534/g3.118.200841] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Several examples of transcription factors that show stochastic, unsynchronized pulses of nuclear localization have been described. Here we show that under constant calcium stress, nuclear localization pulses of the transcription factor Crz1 follow stochastic variations in cytosolic calcium concentration. We find that the size of the stochastic calcium bursts is positively correlated with the number of subsequent Crz1 pulses. Based on our observations, we propose a simple stochastic model of how the signaling pathway converts a constant external calcium concentration into a digital number of Crz1 pulses in the nucleus, due to the time delay from nuclear transport and the stochastic decoherence of individual Crz1 molecule dynamics. We find support for several additional predictions of the model and suggest that stochastic input to nuclear transport may produce noisy digital responses to analog signals in other signaling systems.
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Drumm BT, Hennig GW, Baker SA, Sanders KM. Applications of Spatio-temporal Mapping and Particle Analysis Techniques to Quantify Intracellular Ca2+ Signaling In Situ. J Vis Exp 2019. [PMID: 30663707 DOI: 10.3791/58989] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Ca2+ imaging of isolated cells or specific types of cells within intact tissues often reveals complex patterns of Ca2+ signaling. This activity requires careful and in-depth analyses and quantification to capture as much information about the underlying events as possible. Spatial, temporal and intensity parameters intrinsic to Ca2+ signals such as frequency, duration, propagation, velocity and amplitude may provide some biological information required for intracellular signalling. High-resolution Ca2+ imaging typically results in the acquisition of large data files that are time consuming to process in terms of translating the imaging information into quantifiable data, and this process can be susceptible to human error and bias. Analysis of Ca2+ signals from cells in situ typically relies on simple intensity measurements from arbitrarily selected regions of interest (ROI) within a field of view (FOV). This approach ignores much of the important signaling information contained in the FOV. Thus, in order to maximize recovery of information from such high-resolution recordings obtained with Ca2+dyes or optogenetic Ca2+ imaging, appropriate spatial and temporal analysis of the Ca2+ signals is required. The protocols outlined in this paper will describe how a high volume of data can be obtained from Ca2+ imaging recordings to facilitate more complete analysis and quantification of Ca2+ signals recorded from cells using a combination of spatiotemporal map (STM)-based analysis and particle-based analysis. The protocols also describe how different patterns of Ca2+ signaling observed in different cell populations in situ can be analyzed appropriately. For illustration, the method will examine Ca2+ signaling in a specialized population of cells in the small intestine, interstitial cells of Cajal (ICC), using GECIs.
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Affiliation(s)
- Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine;
| | - Grant W Hennig
- Department of Pharmacology, The Robert Larner, M.D. College of Medicine, University of Vermont
| | - Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine
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Sanders KM. Spontaneous Electrical Activity and Rhythmicity in Gastrointestinal Smooth Muscles. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:3-46. [PMID: 31183821 PMCID: PMC7035145 DOI: 10.1007/978-981-13-5895-1_1] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The gastrointestinal (GI) tract has multifold tasks of ingesting, processing, and assimilating nutrients and disposing of wastes at appropriate times. These tasks are facilitated by several stereotypical motor patterns that build upon the intrinsic rhythmicity of the smooth muscles that generate phasic contractions in many regions of the gut. Phasic contractions result from a cyclical depolarization/repolarization cycle, known as electrical slow waves, which result from intrinsic pacemaker activity. Interstitial cells of Cajal (ICC) are electrically coupled to smooth muscle cells (SMCs) and generate and propagate pacemaker activity and slow waves. The mechanism of slow waves is dependent upon specialized conductances expressed by pacemaker ICC. The primary conductances responsible for slow waves in mice are Ano1, Ca2+-activated Cl- channels (CaCCs), and CaV3.2, T-type, voltage-dependent Ca2+ channels. Release of Ca2+ from intracellular stores in ICC appears to be the initiator of pacemaker depolarizations, activation of T-type current provides voltage-dependent Ca2+ entry into ICC, as slow waves propagate through ICC networks, and Ca2+-induced Ca2+ release and activation of Ano1 in ICC amplifies slow wave depolarizations. Slow waves conduct to coupled SMCs, and depolarization elicited by these events enhances the open-probability of L-type voltage-dependent Ca2+ channels, promotes Ca2+ entry, and initiates contraction. Phasic contractions timed by the occurrence of slow waves provide the basis for motility patterns such as gastric peristalsis and segmentation. This chapter discusses the properties of ICC and proposed mechanism of electrical rhythmicity in GI muscles.
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Affiliation(s)
- Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA.
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Zheng H, Drumm BT, Earley S, Sung TS, Koh SD, Sanders KM. SOCE mediated by STIM and Orai is essential for pacemaker activity in the interstitial cells of Cajal in the gastrointestinal tract. Sci Signal 2018; 11:eaaq0918. [PMID: 29895614 PMCID: PMC6310020 DOI: 10.1126/scisignal.aaq0918] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Electrical pacemaker activity generates phasic contractions and motility patterns such as segmentation and peristalsis in the gastrointestinal tract. Pacemaker currents are generated in interstitial cells of Cajal (ICC), which release Ca2+ from intracellular stores that stimulates Ca2+-activated Cl- channels (CaCCs) in the plasma membrane. Thus, Ca2+ stores must be maintained to sustain pacemaker activity. Store-operated Ca2+ entry (SOCE) facilitates the refilling of Ca2+ stores by a mechanism dependent upon interactions between STIM and Orai proteins. We investigated the role of SOCE in ICC pacemaker activity. Reintroduction of extracellular Ca2+ in store-depleted ICC resulted in CaCC activation. Blocking CaCCs revealed an inwardly rectifying current with properties of a Ca2+ release-activated current (ICRAC). An inhibitory peptide that interfered with the STIM-Orai interaction blocked ICRAC in HEK 293 cells expressing STIM1 and Orai1 and blocked spontaneous transient inward currents (STICs) and slow wave currents in ICC. STICs, which are fundamental pacemaker events in ICC, were blocked by an Orai antagonist. Imaging of Ca2+ transients linked to pacemaker activity in ICC in intact muscles showed that the Orai antagonist blocked Ca2+ transients in ICC. These data suggest that Ca2+ recovery through STIM-Orai interactions is necessary to maintain ICC pacemaker activity.
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Affiliation(s)
- Haifeng Zheng
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Scott Earley
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Tae Sik Sung
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Sang Don Koh
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA.
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Drumm BT, Rembetski BE, Cobine CA, Baker SA, Sergeant GP, Hollywood MA, Thornbury KD, Sanders KM. Ca 2+ signalling in mouse urethral smooth muscle in situ: role of Ca 2+ stores and Ca 2+ influx mechanisms. J Physiol 2018; 596:1433-1466. [PMID: 29383731 PMCID: PMC5899989 DOI: 10.1113/jp275719] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 01/17/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Contraction of urethral smooth muscle cells (USMCs) contributes to urinary continence. Ca2+ signalling in USMCs was investigated in intact urethral muscles using a genetically encoded Ca2+ sensor, GCaMP3, expressed selectively in USMCs. USMCs were spontaneously active in situ, firing intracellular Ca2+ waves that were asynchronous at different sites within cells and between adjacent cells. Spontaneous Ca2+ waves in USMCs were myogenic but enhanced by adrenergic or purinergic agonists and decreased by nitric oxide. Ca2+ waves arose from inositol trisphosphate type 1 receptors and ryanodine receptors, and Ca2+ influx by store-operated calcium entry was required to maintain Ca2+ release events. Ca2+ release and development of Ca2+ waves appear to be the primary source of Ca2+ for excitation-contraction coupling in the mouse urethra, and no evidence was found that voltage-dependent Ca2+ entry via L-type or T-type channels was required for responses to α adrenergic responses. ABSTRACT Urethral smooth muscle cells (USMCs) generate myogenic tone and contribute to urinary continence. Currently, little is known about Ca2+ signalling in USMCs in situ, and therefore little is known about the source(s) of Ca2+ required for excitation-contraction coupling. We characterized Ca2+ signalling in USMCs within intact urethral muscles using a genetically encoded Ca2+ sensor, GCaMP3, expressed selectively in USMCs. USMCs fired spontaneous intracellular Ca2+ waves that did not propagate cell-to-cell across muscle bundles. Ca2+ waves increased dramatically in response to the α1 adrenoceptor agonist phenylephrine (10 μm) and to ATP (10 μm). Ca2+ waves were inhibited by the nitric oxide donor DEA NONOate (10 μm). Ca2+ influx and release from sarcoplasmic reticulum stores contributed to Ca2+ waves, as Ca2+ free bathing solution and blocking the sarcoplasmic Ca2+ -ATPase abolished activity. Intracellular Ca2+ release involved cooperation between ryanadine receptors and inositol trisphosphate receptors, as tetracaine and ryanodine (100 μm) and xestospongin C (1 μm) reduced Ca2+ waves. Ca2+ waves were insensitive to L-type Ca2+ channel modulators nifedipine (1 μm), nicardipine (1 μm), isradipine (1 μm) and FPL 64176 (1 μm), and were unaffected by the T-type Ca2+ channel antagonists NNC-550396 (1 μm) and TTA-A2 (1 μm). Ca2+ waves were reduced by the store operated Ca2+ entry blocker SKF 96365 (10 μm) and by an Orai antagonist, GSK-7975A (1 μm). The latter also reduced urethral contractions induced by phenylephrine, suggesting that Orai can function effectively as a receptor-operated channel. In conclusion, Ca2+ waves in mouse USMCs are a source of Ca2+ for excitation-contraction coupling in urethral muscles.
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Affiliation(s)
- Bernard T. Drumm
- Department of Physiology and Cell BiologyUniversity of Nevada, Reno School of MedicineRenoNV89557USA
| | - Benjamin E. Rembetski
- Department of Physiology and Cell BiologyUniversity of Nevada, Reno School of MedicineRenoNV89557USA
| | - Caroline A. Cobine
- Department of Physiology and Cell BiologyUniversity of Nevada, Reno School of MedicineRenoNV89557USA
| | - Salah A. Baker
- Department of Physiology and Cell BiologyUniversity of Nevada, Reno School of MedicineRenoNV89557USA
| | - Gerard P. Sergeant
- Smooth Muscle Research CentreDundalk Institute of TechnologyCo. LouthDundalkRepublic of Ireland
| | - Mark A. Hollywood
- Smooth Muscle Research CentreDundalk Institute of TechnologyCo. LouthDundalkRepublic of Ireland
| | - Keith D. Thornbury
- Smooth Muscle Research CentreDundalk Institute of TechnologyCo. LouthDundalkRepublic of Ireland
| | - Kenton M. Sanders
- Department of Physiology and Cell BiologyUniversity of Nevada, Reno School of MedicineRenoNV89557USA
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Baker SA, Drumm BT, Cobine CA, Keef KD, Sanders KM. Inhibitory Neural Regulation of the Ca 2+ Transients in Intramuscular Interstitial Cells of Cajal in the Small Intestine. Front Physiol 2018; 9:328. [PMID: 29686622 PMCID: PMC5900014 DOI: 10.3389/fphys.2018.00328] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 03/15/2018] [Indexed: 01/03/2023] Open
Abstract
Gastrointestinal motility is coordinated by enteric neurons. Both inhibitory and excitatory motor neurons innervate the syncytium consisting of smooth muscle cells (SMCs) interstitial cells of Cajal (ICC) and PDGFRα+ cells (SIP syncytium). Confocal imaging of mouse small intestines from animals expressing GCaMP3 in ICC were used to investigate inhibitory neural regulation of ICC in the deep muscular plexus (ICC-DMP). We hypothesized that Ca2+ signaling in ICC-DMP can be modulated by inhibitory enteric neural input. ICC-DMP lie in close proximity to the varicosities of motor neurons and generate ongoing Ca2+ transients that underlie activation of Ca2+-dependent Cl- channels and regulate the excitability of SMCs in the SIP syncytium. Electrical field stimulation (EFS) caused inhibition of Ca2+ for the first 2-3 s of stimulation, and then Ca2+ transients escaped from inhibition. The NO donor (DEA-NONOate) inhibited Ca2+ transients and Nω-Nitro-L-arginine (L-NNA) or a guanylate cyclase inhibitor (ODQ) blocked inhibition induced by EFS. Purinergic neurotransmission did not affect Ca2+ transients in ICC-DMP. Purinergic neurotransmission elicits hyperpolarization of the SIP syncytium by activation of K+ channels in PDGFRα+ cells. Generalized hyperpolarization of SIP cells by pinacidil (KATP agonist) or MRS2365 (P2Y1 agonist) also had no effect on Ca2+ transients in ICC-DMP. Peptidergic transmitter receptors (VIP and PACAP) are expressed in ICC and can modulate ICC-DMP Ca2+ transients. In summary Ca2+ transients in ICC-DMP are blocked by enteric inhibitory neurotransmission. ICC-DMP lack a voltage-dependent mechanism for regulating Ca2+ release, and this protects Ca2+ handling in ICC-DMP from membrane potential changes in other SIP cells.
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Affiliation(s)
| | | | | | | | - Kenton M. Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno, NV, United States
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Xie Y, Han KH, Grainger N, Li W, Corrigan RD, Perrino BA. A role for focal adhesion kinase in facilitating the contractile responses of murine gastric fundus smooth muscles. J Physiol 2018. [PMID: 29528115 DOI: 10.1113/jp275406] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
KEY POINTS Activation of focal adhesion kinase (FAK) by integrin signalling facilitates smooth muscle contraction by transmitting the force generated by myofilament activation to the extracellular matrix and throughout the smooth muscle tissue. Here we report that electrical field stimulation (EFS) of cholinergic motor neurons activates FAK in gastric fundus smooth muscles, and that FAK activation by EFS is atropine-sensitive but nicardipine-insensitive. PDBu and calyculin A contracted gastric fundus muscles Ca2+ -independently and also activated FAK. Inhibition of FAK activation inhibits the contractile responses evoked by EFS, and inhibits CPI-17 phosphorylation at T38. This study indicates that mechanical force or tension is sufficient to activate FAK, and that FAK appears to be involved in the activation of the protein kinase C-CPI-17 Ca2+ sensitization pathway in gastric fundus smooth muscles. These results reveal a novel role for FAK in gastric fundus smooth muscle contraction by facilitating CPI-17 phosphorylation. ABSTRACT Smooth muscle contraction involves regulating myosin light chain phosphorylation and dephosphorylation by myosin light chain kinase and myosin light chain phosphatase. C-kinase potentiated protein phosphatase-1 inhibitor of 17 kDa (CPI-17) and myosin phosphatase targeting subunit of myosin light-chain phosphatase (MYPT1) are crucial for regulating gastrointestinal smooth muscle contraction by inhibiting myosin light chain phosphatase. Integrin signalling involves the dynamic recruitment of several proteins, including focal adhesion kinase (FAK), to focal adhesions. FAK tyrosine kinase activation is involved in cell adhesion to the extracellular matrix via integrin signalling. FAK participates in linking the force generated by myofilament activation to the extracellular matrix and throughout the smooth muscle tissue. Here, we show that cholinergic stimulation activates FAK in gastric fundus smooth muscles. Electrical field stimulation in the presence of Nω -nitro-l-arginine methyl ester and MRS2500 contracted gastric fundus smooth muscle strips and increased FAK Y397 phosphorylation (pY397). Atropine blocked the contractions and prevented the increase in pY397. The FAK inhibitor PF-431396 inhibited the contractions and the increase in pY397. PF-431396 also inhibited the electrical field stimulation-induced increase in CPI-17 T38 phosphorylation, and reduced MYPT1 T696 and T853, and myosin light chain S19 phosphorylation. Ca2+ influx was unaffected by PF-431396. Nicardipine inhibited the contractions but had no effect on the increase in pY397. Phorbol 12,13-dibutyrate or calyculin A contracted gastric fundus smooth muscle strips Ca2+ independently and increased pY397. Our findings suggest that FAK is activated by mechanical forces during contraction and reveal a novel role of FAK in the regulation of CPI-17 phosphorylation.
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Affiliation(s)
- Yeming Xie
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, NV, 89557, USA
| | - Koon Hee Han
- Department of Internal Medicine, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Republic of Korea
| | - Nathan Grainger
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, NV, 89557, USA
| | - Wen Li
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, NV, 89557, USA
| | - Robert D Corrigan
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, NV, 89557, USA
| | - Brian A Perrino
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, NV, 89557, USA
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36
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Excitatory Neuronal Responses of Ca 2+ Transients in Interstitial Cells of Cajal in the Small Intestine. eNeuro 2018; 5:eN-NWR-0080-18. [PMID: 29632869 PMCID: PMC5889480 DOI: 10.1523/eneuro.0080-18.2018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 03/12/2018] [Indexed: 12/26/2022] Open
Abstract
Interstitial cells of Cajal (ICC) regulate smooth muscle excitability and motility in the gastrointestinal (GI) tract. ICC in the deep muscular plexus (ICC-DMP) of the small intestine are aligned closely with varicosities of enteric motor neurons and thought to transduce neural responses. ICC-DMP generate Ca2+ transients that activate Ca2+ activated Cl- channels and generate electrophysiological responses. We tested the hypothesis that excitatory neurotransmitters regulate Ca2+ transients in ICC-DMP as a means of regulating intestinal muscles. High-resolution confocal microscopy was used to image Ca2+ transients in ICC-DMP within murine small intestinal muscles with cell-specific expression of GCaMP3. Intrinsic nerves were stimulated by electrical field stimulation (EFS). ICC-DMP exhibited ongoing Ca2+ transients before stimuli were applied. EFS caused initial suppression of Ca2+ transients, followed by escape during sustained stimulation, and large increases in Ca2+ transients after cessation of stimulation. Basal Ca2+ activity and the excitatory phases of Ca2+ responses to EFS were inhibited by atropine and neurokinin 1 receptor (NK1) antagonists, but not by NK2 receptor antagonists. Exogenous ACh and substance P (SP) increased Ca2+ transients, atropine and NK1 antagonists decreased Ca2+ transients. Neurokinins appear to be released spontaneously (tonic excitation) in small intestinal muscles and are the dominant excitatory neurotransmitters. Subcellular regulation of Ca2+ release events in ICC-DMP may be a means by which excitatory neurotransmission organizes intestinal motility patterns.
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Iskander SM, Feeney MM, Yee K, Rosenblum ND. Protein Kinase 2 β Is Expressed in Neural Crest-Derived Urinary Pacemaker Cells and Required for Pyeloureteric Contraction. J Am Soc Nephrol 2018; 29:1198-1209. [PMID: 29436516 DOI: 10.1681/asn.2017090951] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 01/10/2018] [Indexed: 01/31/2023] Open
Abstract
Nonobstructive hydronephrosis, defined as dilatation of the renal pelvis with or without dilatation of the ureter, is the most common antenatal abnormality detected by fetal ultrasound. Yet, the etiology of nonobstructive hydronephrosis is poorly defined. We previously demonstrated that defective development of urinary tract pacemaker cells (utPMCs) expressing hyperpolarization-activated cyclic nucleotide-gated channel 3 (HCN3) and the stem cell marker cKIT causes abnormal ureteric peristalsis and nonobstructive hydronephrosis. However, further investigation of utPMC development and function is limited by lack of knowledge regarding the embryonic derivation, development, and molecular apparatus of these cells. Here, we used lineage tracing in mice to identify cells that give rise to utPMCs. Neural crest cells (NCCs) indelibly labeled with tdTomato expressed HCN3 and cKIT. Furthermore, purified HCN3+ and cKIT+ utPMCs were enriched in Sox10 and Tfap-2α, markers of NCCs. Sequencing of purified RNA from HCN3+ cells revealed enrichment of a small subset of RNAs, including RNA encoding protein kinase 2β (PTK2β), a Ca2+-dependent tyrosine kinase that regulates ion channel activity in neurons. Immunofluorescence analysis in situ revealed PTK2β expression in NCCs as early as embryonic day 12.5 and in HCN3+ and cKIT+ utPMCs as early as embryonic day 15.5, with sustained expression in HCN3+ utPMCs until postnatal week 8. Pharmacologic inhibition of PTK2β in murine pyeloureteral tissue explants inhibited contraction frequency. Together, these results demonstrate that utPMCs are derived from NCCs, identify new markers of utPMCs, and demonstrate a functional contribution of PTK2β to utPMC function.
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Affiliation(s)
- Samir M Iskander
- Program in Developmental and Stem Cell Biology and.,Departments of Laboratory Medicine and Pathobiology and
| | - Meghan M Feeney
- Program in Developmental and Stem Cell Biology and.,Departments of Laboratory Medicine and Pathobiology and
| | - Kirby Yee
- Program in Developmental and Stem Cell Biology and
| | - Norman D Rosenblum
- Program in Developmental and Stem Cell Biology and .,Departments of Laboratory Medicine and Pathobiology and.,Division of Nephrology, The Hospital for Sick Children, Toronto, Ontario, Canada; and.,Paediatrics, University of Toronto, Toronto, Ontario, Canada
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38
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Drumm BT, Sung TS, Zheng H, Baker SA, Koh SD, Sanders KM. The effects of mitochondrial inhibitors on Ca 2+ signalling and electrical conductances required for pacemaking in interstitial cells of Cajal in the mouse small intestine. Cell Calcium 2018; 72:1-17. [PMID: 29748128 DOI: 10.1016/j.ceca.2018.01.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 01/26/2018] [Accepted: 01/27/2018] [Indexed: 01/16/2023]
Abstract
Interstitial cells of Cajal (ICC-MY) are pacemakers that generate and propagate electrical slow waves in gastrointestinal (GI) muscles. Slow waves appear to be generated by the release of Ca2+ from intracellular stores and activation of Ca2+-activated Cl- channels (Ano1). Conduction of slow waves to smooth muscle cells coordinates rhythmic contractions. Mitochondrial Ca2+ handling is currently thought to be critical for ICC pacemaking. Protonophores, inhibitors of the electron transport chain (FCCP, CCCP or antimycin) or mitochondrial Na+/Ca2+ exchange blockers inhibited slow waves in several GI muscles. Here we utilized Ca2+ imaging of ICC in small intestinal muscles in situ to determine the effects of mitochondrial drugs on Ca2+ transients in ICC. Muscles were obtained from mice expressing a genetically encoded Ca2+ indicator (GCaMP3) in ICC. FCCP, CCCP, antimycin, a uniporter blocker, Ru360, and a mitochondrial Na+/Ca2+ exchange inhibitor, CGP-37157 inhibited Ca2+ transients in ICC-MY. Effects were not due to depletion of ATP, as oligomycin did not affect Ca2+ transients. Patch-clamp experiments were performed to test the effects of the mitochondrial drugs on key pacemaker conductances, Ano1 and T-type Ca2+ (CaV3.2), in HEK293 cells. Antimycin blocked Ano1 and reduced CaV3.2 currents. CCCP blocked CaV3.2 current but did not affect Ano1 current. Ano1 and Cav3.2 currents were inhibited by CGP-37157. Inhibitory effects of mitochondrial drugs on slow waves and Ca2+ signalling in ICC can be explained by direct antagonism of key pacemaker conductances in ICC that generate and propagate slow waves. A direct obligatory role for mitochondria in pacemaker activity is therefore questionable.
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Affiliation(s)
- Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA
| | - Tae S Sung
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA
| | - Haifeng Zheng
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA
| | - Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA
| | - Sang D Koh
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA.
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39
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Boesmans W, Hao MM, Vanden Berghe P. Optogenetic and chemogenetic techniques for neurogastroenterology. Nat Rev Gastroenterol Hepatol 2018; 15:21-38. [PMID: 29184183 DOI: 10.1038/nrgastro.2017.151] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Optogenetics and chemogenetics comprise a wide variety of applications in which genetically encoded actuators and indicators are used to modulate and monitor activity with high cellular specificity. Over the past 10 years, development of these genetically encoded tools has contributed tremendously to our understanding of integrated physiology. In concert with the continued refinement of probes, strategies to target transgene expression to specific cell types have also made much progress in the past 20 years. In addition, the successful implementation of optogenetic and chemogenetic techniques thrives thanks to ongoing advances in live imaging microscopy and optical technology. Although innovation of optogenetic and chemogenetic methods has been primarily driven by researchers studying the central nervous system, these techniques also hold great promise to boost research in neurogastroenterology. In this Review, we describe the different classes of tools that are currently available and give an overview of the strategies to target them to specific cell types in the gut wall. We discuss the possibilities and limitations of optogenetic and chemogenetic technology in the gut and provide an overview of their current use, with a focus on the enteric nervous system. Furthermore, we suggest some experiments that can advance our understanding of how the intrinsic and extrinsic neural networks of the gut control gastrointestinal function.
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Affiliation(s)
- Werend Boesmans
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Herestraat 49, O&N 1 Box 701, 3000 Leuven, Belgium.,Department of Pathology, Maastricht University Medical Center, P. Debeijelaan 25, 6229 HX, Maastricht, The Netherlands
| | - Marlene M Hao
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Herestraat 49, O&N 1 Box 701, 3000 Leuven, Belgium.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Pieter Vanden Berghe
- Laboratory for Enteric Neuroscience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Herestraat 49, O&N 1 Box 701, 3000 Leuven, Belgium
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40
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Ha SE, Lee MY, Kurahashi M, Wei L, Jorgensen BG, Park C, Park PJ, Redelman D, Sasse KC, Becker LS, Sanders KM, Ro S. Transcriptome analysis of PDGFRα+ cells identifies T-type Ca2+ channel CACNA1G as a new pathological marker for PDGFRα+ cell hyperplasia. PLoS One 2017; 12:e0182265. [PMID: 28806761 PMCID: PMC5555714 DOI: 10.1371/journal.pone.0182265] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 07/14/2017] [Indexed: 12/11/2022] Open
Abstract
Platelet-derived growth factor receptor alpha (PDGFRα)+ cells are distributed into distinct morphological groups within the serosal, muscular, and submucosal layers as well as the myenteric and deep muscular plexi. PDGFRα+ cells directly interact with interstitial cells of Cajal (ICC) and smooth muscle cells (SMC) in gastrointestinal smooth muscle tissue. These three cell types, SMC, ICC, and PDGFRα+ cells (SIP cells), form an electrical syncytium, which dynamically regulates gastrointestinal motility. We have previously reported the transcriptomes of SMC and ICC. To complete the SIP cell transcriptome project, we obtained transcriptome data from jejunal and colonic PDGFRα+ cells. The PDGFRα+ cell transcriptome data were added to the Smooth Muscle Genome Browser that we previously built for the genome-scale gene expression data of ICC and SMC. This browser provides a comprehensive reference for all transcripts expressed in SIP cells. By analyzing the transcriptomes, we have identified a unique set of PDGFRα+ cell signature genes, growth factors, transcription factors, epigenetic enzymes/regulators, receptors, protein kinases/phosphatases, and ion channels/transporters. We demonstrated that the low voltage-dependent T-type Ca2+ channel Cacna1g gene was particularly expressed in PDGFRα+ cells in the intestinal serosal layer in mice. Expression of this gene was significantly induced in the hyperplasic PDGFRα+ cells of obstructed small intestine in mice. This gene was also over-expressed in colorectal cancer, Crohn's disease, and diverticulitis in human patients. Taken together, our data suggest that Cacna1g exclusively expressed in serosal PDGFRα+ cells is a new pathological marker for gastrointestinal diseases.
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Affiliation(s)
- Se Eun Ha
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States of America
| | - Moon Young Lee
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States of America
- Department of Physiology, Wonkwang Digestive Disease Research Institute and Institute of Wonkwang Medical Science, School of Medicine, Wonkwang University, Iksan, Chonbuk, Korea
| | - Masaaki Kurahashi
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States of America
| | - Lai Wei
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States of America
| | - Brian G. Jorgensen
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States of America
| | - Chanjae Park
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States of America
| | - Paul J. Park
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States of America
| | - Doug Redelman
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States of America
| | - Kent C. Sasse
- Sasse Surgical Associates, Reno, Nevada, United States of America
| | - Laren S. Becker
- Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Kenton M. Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States of America
| | - Seungil Ro
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, United States of America
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41
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Drumm BT, Hennig GW, Battersby MJ, Cunningham EK, Sung TS, Ward SM, Sanders KM, Baker SA. Clustering of Ca 2+ transients in interstitial cells of Cajal defines slow wave duration. J Gen Physiol 2017; 149:703-725. [PMID: 28592421 PMCID: PMC5496507 DOI: 10.1085/jgp.201711771] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 05/02/2017] [Indexed: 12/13/2022] Open
Abstract
Electrical slow waves in the small intestine are generated by pacemaker cells called interstitial cells of Cajal. Drumm et al. record clusters of Ca2+ transients in these cells that are entrained by voltage-dependent Ca2+ entry and which define the duration of the electrical slow waves. Interstitial cells of Cajal (ICC) in the myenteric plexus region (ICC-MY) of the small intestine are pacemakers that generate rhythmic depolarizations known as slow waves. Slow waves depend on activation of Ca2+-activated Cl− channels (ANO1) in ICC, propagate actively within networks of ICC-MY, and conduct to smooth muscle cells where they generate action potentials and phasic contractions. Thus, mechanisms of Ca2+ regulation in ICC are fundamental to the motor patterns of the bowel. Here, we characterize the nature of Ca2+ transients in ICC-MY within intact muscles, using mice expressing a genetically encoded Ca2+ sensor, GCaMP3, in ICC. Ca2+ transients in ICC-MY display a complex firing pattern caused by localized Ca2+ release events arising from multiple sites in cell somata and processes. Ca2+ transients are clustered within the time course of slow waves but fire asynchronously during these clusters. The durations of Ca2+ transient clusters (CTCs) correspond to slow wave durations (plateau phase). Simultaneous imaging and intracellular electrical recordings revealed that the upstroke depolarization of slow waves precedes clusters of Ca2+ transients. Summation of CTCs results in relatively uniform Ca2+ responses from one slow wave to another. These Ca2+ transients are caused by Ca2+ release from intracellular stores and depend on ryanodine receptors as well as amplification from IP3 receptors. Reduced extracellular Ca2+ concentrations and T-type Ca2+ channel blockers decreased the number of firing sites and firing probability of Ca2+ transients. In summary, the fundamental electrical events of small intestinal muscles generated by ICC-MY depend on asynchronous firing of Ca2+ transients from multiple intracellular release sites. These events are organized into clusters by Ca2+ influx through T-type Ca2+ channels to sustain activation of ANO1 channels and generate the plateau phase of slow waves.
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Affiliation(s)
- Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV
| | - Grant W Hennig
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV
| | - Matthew J Battersby
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV
| | - Erin K Cunningham
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV
| | - Tae Sik Sung
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV
| | - Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV
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42
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Gulbransen BD. Emerging tools to study enteric neuromuscular function. Am J Physiol Gastrointest Liver Physiol 2017; 312:G420-G426. [PMID: 28280142 PMCID: PMC5451564 DOI: 10.1152/ajpgi.00049.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/07/2017] [Accepted: 03/07/2017] [Indexed: 01/31/2023]
Abstract
Investigating enteric neuromuscular function poses specific challenges that are not encountered in other systems. The gut has a complex cellular composition, and methods to study diverse multicellular interactions during physiological gut functions have been limited. However, new technologies are emerging in optics, genetics, and bioengineering that greatly expand the capabilities to study integrative functions in the gut. In this mini-review, I discuss several areas where the application of these technologies could benefit ongoing efforts to understand enteric neuromuscular function. I specifically focus on technologies that can be applied to study specific cellular networks and the mechanisms that link activity to function.
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Affiliation(s)
- Brian D. Gulbransen
- Neuroscience Program, Department of Physiology, Michigan State University, East Lansing, Michigan
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43
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Sanders KM, Kito Y, Hwang SJ, Ward SM. Regulation of Gastrointestinal Smooth Muscle Function by Interstitial Cells. Physiology (Bethesda) 2017; 31:316-26. [PMID: 27488743 DOI: 10.1152/physiol.00006.2016] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Interstitial cells of mesenchymal origin form gap junctions with smooth muscle cells in visceral smooth muscles and provide important regulatory functions. In gastrointestinal (GI) muscles, there are two distinct classes of interstitial cells, c-Kit(+) interstitial cells of Cajal and PDGFRα(+) cells, that regulate motility patterns. Loss of these cells may contribute to symptoms in GI motility disorders.
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Affiliation(s)
- Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine, Reno, Nevada; and
| | - Yoshihiko Kito
- Department of Pharmacology, Faculty of Medicine, Saga University, Nabeshima, Japan
| | - Sung Jin Hwang
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine, Reno, Nevada; and
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine, Reno, Nevada; and
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Malysz J, Gibbons SJ, Saravanaperumal SA, Du P, Eisenman ST, Cao C, Oh U, Saur D, Klein S, Ordog T, Farrugia G. Conditional genetic deletion of Ano1 in interstitial cells of Cajal impairs Ca 2+ transients and slow waves in adult mouse small intestine. Am J Physiol Gastrointest Liver Physiol 2017; 312:G228-G245. [PMID: 27979828 PMCID: PMC5401988 DOI: 10.1152/ajpgi.00363.2016] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/05/2016] [Accepted: 12/12/2016] [Indexed: 01/31/2023]
Abstract
Myenteric plexus interstitial cells of Cajal (ICC-MY) in the small intestine are Kit+ electrical pacemakers that express the Ano1/TMEM16A Ca2+-activated Cl- channel, whose functions in the gastrointestinal tract remain incompletely understood. In this study, an inducible Cre-LoxP-based approach was used to advance the understanding of Ano1 in ICC-MY of adult mouse small intestine. KitCreERT2/+;Ano1Fl/Fl mice were treated with tamoxifen or vehicle, and small intestines (mucosa free) were examined. Quantitative RT-PCR demonstrated ~50% reduction in Ano1 mRNA in intestines of conditional knockouts (cKOs) compared with vehicle-treated controls. Whole mount immunohistochemistry showed a mosaic/patchy pattern loss of Ano1 protein in ICC networks. Ca2+ transients in ICC-MY network of cKOs displayed reduced duration compared with highly synchronized controls and showed synchronized and desynchronized profiles. When matched, the rank order for Ano1 expression in Ca2+ signal imaged fields of view was as follows: vehicle controls>>>cKO(synchronized)>cKO(desynchronized). Maintenance of Ca2+ transients' synchronicity despite high loss of Ano1 indicates a large functional reserve of Ano1 in the ICC-MY network. Slow waves in cKOs displayed reduced duration and increased inter-slow-wave interval and occurred in regular- and irregular-amplitude oscillating patterns. The latter activity suggested ongoing interaction by independent interacting oscillators. Lack of slow waves and depolarization, previously reported for neonatal constitutive knockouts, were also seen. In summary, Ano1 in adults regulates gastrointestinal function by determining Ca2+ transients and electrical activity depending on the level of Ano1 expression. Partial Ano1 loss results in Ca2+ transients and slow waves displaying reduced duration, while complete and widespread absence of Ano1 in ICC-MY causes lack of slow wave and desynchronized Ca2+ transients.NEW & NOTEWORTHY The Ca2+-activated Cl- channel, Ano1, in interstitial cells of Cajal (ICC) is necessary for normal gastrointestinal motility. We knocked out Ano1 to varying degrees in ICC of adult mice. Partial knockout of Ano1 shortened the widths of electrical slow waves and Ca2+ transients in myenteric ICC but Ca2+ transient synchronicity was preserved. Near-complete knockout was necessary for transient desynchronization and loss of slow waves, indicating a large functional reserve of Ano1 in ICC.
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Affiliation(s)
- John Malysz
- Enteric NeuroScience Program, Mayo Clinic, Rochester, Minnesota
| | - Simon J Gibbons
- Enteric NeuroScience Program, Mayo Clinic, Rochester, Minnesota
| | | | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Seth T Eisenman
- Enteric NeuroScience Program, Mayo Clinic, Rochester, Minnesota
| | - Chike Cao
- Enteric NeuroScience Program, Mayo Clinic, Rochester, Minnesota
| | - Uhtaek Oh
- Sensory Research Center, CRI, College of Pharmacy, Seoul National University, Seoul, Republic of Korea; and
| | - Dieter Saur
- Department of Internal Medicine II, Klinikum rechts der Isar, Technische Universität München, München, Germany
| | - Sabine Klein
- Department of Internal Medicine II, Klinikum rechts der Isar, Technische Universität München, München, Germany
| | - Tamas Ordog
- Enteric NeuroScience Program, Mayo Clinic, Rochester, Minnesota
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Cobine CA, Hannah EE, Zhu MH, Lyle HE, Rock JR, Sanders KM, Ward SM, Keef KD. ANO1 in intramuscular interstitial cells of Cajal plays a key role in the generation of slow waves and tone in the internal anal sphincter. J Physiol 2017; 595:2021-2041. [PMID: 28054347 DOI: 10.1113/jp273618] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 12/16/2016] [Indexed: 12/13/2022] Open
Abstract
KEY POINTS The internal anal sphincter develops tone important for maintaining high anal pressure and continence. Controversy exists regarding the mechanisms underlying tone development. We examined the hypothesis that tone depends upon electrical slow waves (SWs) initiated in intramuscular interstitial cells of Cajal (ICC-IM) by activation of Ca2+ -activated Cl- channels (ANO1, encoded by Ano1) and voltage-dependent L-type Ca2+ channels (CavL , encoded by Cacna1c). Measurement of membrane potential and contraction indicated that ANO1 and CavL have a central role in SW generation, phasic contractions and tone, independent of stretch. ANO1 expression was examined in wildtype and Ano1/+egfp mice with immunohistochemical techniques. Ano1 and Cacna1c expression levels were examined by quantitative PCR in fluorescence-activated cell sorting. ICC-IM were the predominant cell type expressing ANO1 and the most likely candidate for SW generation. SWs in ICC-IM are proposed to conduct to smooth muscle where Ca2+ entry via CavL results in phasic activity that sums to produce tone. ABSTRACT The mechanism underlying tone generation in the internal anal sphincter (IAS) is controversial. We examined the hypothesis that tone depends upon generation of electrical slow waves (SWs) initiated in intramuscular interstitial cells of Cajal (ICC-IM) by activation of Ca2+ -activated Cl- channels (encoded by Ano1) and voltage-dependent L-type Ca2+ channels (encoded by Cacna1c). Phasic contractions and tone in the IAS were nearly abolished by ANO1 and CavL antagonists. ANO1 antagonists also abolished SWs as well as transient depolarizations that persisted after addition of CavL antagonists. Tone development in the IAS did not require stretch of muscles, and the sensitivity of contraction to ANO1 antagonists was the same in stretched versus un-stretched muscles. ANO1 expression was examined in wildtype and Ano1/+egfp mice with immunohistochemical techniques. Dual labelling revealed that ANO1 expression could be resolved in ICC but not smooth muscle cells (SMCs) in the IAS and rectum. Ano1, Cacna1c and Kit gene expression were the same in extracts of IAS and rectum muscles. In IAS cells isolated with fluorescence-activated cell sorting, Ano1 expression was 26.5-fold greater in ICC than in SMCs while Cacna1c expression was only 2-fold greater in SMCs than in ICC. These data support a central role for ANO1 and CavL in the generation of SWs and tone in the IAS. ICC-IM are the probable cellular candidate for ANO1 currents and SW generation. We propose that ANO1 and CavL collaborate to generate SWs in ICC-IM followed by conduction to adjacent SMCs where phasic calcium entry through CavL sums to produce tone.
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Affiliation(s)
- C A Cobine
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - E E Hannah
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - M H Zhu
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - H E Lyle
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - J R Rock
- Department of Anatomy, UCSF School of Medicine, San Francisco, CA, 94143, USA
| | - K M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - S M Ward
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - K D Keef
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
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Radu BM, Banciu A, Banciu DD, Radu M, Cretoiu D, Cretoiu SM. Calcium Signaling in Interstitial Cells: Focus on Telocytes. Int J Mol Sci 2017; 18:ijms18020397. [PMID: 28208829 PMCID: PMC5343932 DOI: 10.3390/ijms18020397] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/04/2017] [Accepted: 01/25/2017] [Indexed: 02/08/2023] Open
Abstract
In this review, we describe the current knowledge on calcium signaling pathways in interstitial cells with a special focus on interstitial cells of Cajal (ICCs), interstitial Cajal-like cells (ICLCs), and telocytes. In detail, we present the generation of Ca2+ oscillations, the inositol triphosphate (IP3)/Ca2+ signaling pathway and modulation exerted by cytokines and vasoactive agents on calcium signaling in interstitial cells. We discuss the physiology and alterations of calcium signaling in interstitial cells, and in particular in telocytes. We describe the physiological contribution of calcium signaling in interstitial cells to the pacemaking activity (e.g., intestinal, urinary, uterine or vascular pacemaking activity) and to the reproductive function. We also present the pathological contribution of calcium signaling in interstitial cells to the aortic valve calcification or intestinal inflammation. Moreover, we summarize the current knowledge of the role played by calcium signaling in telocytes in the uterine, cardiac and urinary physiology, and also in various pathologies, including immune response, uterine and cardiac pathologies.
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Affiliation(s)
- Beatrice Mihaela Radu
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona 37134, Italy.
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest 050095, Romania.
| | - Adela Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest 050095, Romania.
- Research Beyond Limits, Dimitrie Cantemir 15, Bucharest 040234, Romania.
- Engineering Faculty, Constantin Brancusi University, Calea Eroilor 30, Targu Jiu 210135, Romania.
| | - Daniel Dumitru Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, Bucharest 050095, Romania.
- Research Beyond Limits, Dimitrie Cantemir 15, Bucharest 040234, Romania.
| | - Mihai Radu
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona 37134, Italy.
- Department of Life and Environmental Physics, Horia Hulubei National Institute of Physics and Nuclear Engineering, Reactorului 30, P.O. Box MG-6, Magurele 077125, Romania.
| | - Dragos Cretoiu
- Division of Cell Biology and Histology, Carol Davila University of Medicine and Pharmacy, Bucharest 050474, Romania.
- Victor Babes National Institute of Pathology, Bucharest 050096, Romania.
| | - Sanda Maria Cretoiu
- Division of Cell Biology and Histology, Carol Davila University of Medicine and Pharmacy, Bucharest 050474, Romania.
- Victor Babes National Institute of Pathology, Bucharest 050096, Romania.
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Problems with extracellular recording of electrical activity in gastrointestinal muscle. Nat Rev Gastroenterol Hepatol 2016; 13:731-741. [PMID: 27756919 PMCID: PMC8325940 DOI: 10.1038/nrgastro.2016.161] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Motility patterns of the gastrointestinal tract are important for efficient processing of nutrients and waste. Peristalsis and segmentation are based on rhythmic electrical slow waves that generate the phasic contractions fundamental to gastrointestinal motility. Slow waves are generated and propagated actively by interstitial cells of Cajal (ICC), and these events conduct to smooth muscle cells to elicit excitation-contraction coupling. Extracellular electrical recording has been utilized to characterize slow-wave generation and propagation and abnormalities that might be responsible for gastrointestinal motility disorders. Electrode array recording and digital processing are being used to generate data for models of electrical propagation in normal and pathophysiological conditions. Here, we discuss techniques of extracellular recording as applied to gastrointestinal organs and how mechanical artefacts might contaminate these recordings and confound their interpretation. Without rigorous controls for movement, current interpretations of extracellular recordings might ascribe inaccurate behaviours and electrical anomalies to ICC networks and gastrointestinal muscles, bringing into question the findings and validity of models of gastrointestinal electrophysiology developed from these recordings.
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