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Gupta N, Baker SA, Sanders KM, Griffin CS, Sergeant GP, Hollywood MA, Thornbury KD, Drumm BT. Interstitial cell of Cajal-like cells (ICC-LC) exhibit dynamic spontaneous activity but are not functionally innervated in mouse urethra. Cell Calcium 2024; 123:102931. [PMID: 39068674 DOI: 10.1016/j.ceca.2024.102931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 07/09/2024] [Accepted: 07/20/2024] [Indexed: 07/30/2024]
Abstract
Urethral smooth muscle cells (USMC) contract to occlude the internal urethral sphincter during bladder filling. Interstitial cells also exist in urethral smooth muscles and are hypothesized to influence USMC behaviours and neural responses. These cells are similar to Kit+ interstitial cells of Cajal (ICC), which are gastrointestinal pacemakers and neuroeffectors. Isolated urethral ICC-like cells (ICC-LC) exhibit spontaneous intracellular Ca2+ signalling behaviours that suggest these cells may serve as pacemakers or neuromodulators similar to ICC in the gut, although observation and direct stimulation of ICC-LC within intact urethral tissues is lacking. We used mice with cell-specific expression of the Ca2+ indicator, GCaMP6f, driven off the endogenous promoter for Kit (Kit-GCaMP6f mice) to identify ICC-LC in situ within urethra muscles and to characterize spontaneous and nerve-evoked Ca2+ signalling. ICC-LC generated Ca2+ waves spontaneously that propagated on average 40.1 ± 0.7 μm, with varying amplitudes, durations, and spatial spread. These events originated from multiple firing sites in cells and the activity between sites was not coordinated. ICC-LC in urethra formed clusters but not interconnected networks. No evidence for entrainment of Ca2+ signalling between ICC-LC was obtained. Ca2+ events in ICC-LC were unaffected by nifedipine but were abolished by cyclopiazonic acid and decreased by an antagonist of Orai Ca2+ channels (GSK-7975A). Phenylephrine increased Ca2+ event frequency but a nitric oxide donor (DEA-NONOate) had no effect. Electrical field stimulation (EFS, 10 Hz) of intrinsic nerves, which evoked contractions of urethral rings and increased Ca2+ event firing in USMC, failed to evoke responses in ICC-LC. Our data suggest that urethral ICC-LC are spontaneously active but are not regulated by autonomic neurons.
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Affiliation(s)
- Neha Gupta
- Smooth Muscle Research Centre, Department of Life & Health Science, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Salah A Baker
- 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
| | - Caoimhin S Griffin
- Smooth Muscle Research Centre, Department of Life & Health Science, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Gerard P Sergeant
- Smooth Muscle Research Centre, Department of Life & Health Science, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Mark A Hollywood
- Smooth Muscle Research Centre, Department of Life & Health Science, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Keith D Thornbury
- Smooth Muscle Research Centre, Department of Life & Health Science, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - 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.
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Taheri N, Choi EL, Nguyen VTT, Zhang Y, Huynh NM, Kellogg TA, van Wijnen AJ, Ordog T, Hayashi Y. Inhibition of EZH2 Reduces Aging-Related Decline in Interstitial Cells of Cajal of the Mouse Stomach. Cell Mol Gastroenterol Hepatol 2024; 18:101376. [PMID: 38969206 DOI: 10.1016/j.jcmgh.2024.101376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 06/27/2024] [Accepted: 06/27/2024] [Indexed: 07/07/2024]
Abstract
BACKGROUND & AIMS Restricted gastric motor functions contribute to aging-associated undernutrition, sarcopenia, and frailty. We previously identified a decline in interstitial cells of Cajal (ICC; gastrointestinal pacemaker and neuromodulator cells) and their stem cells (ICC-SC) as a key factor of gastric aging. Altered functionality of the histone methyltransferase enhancer of zeste homolog 2 (EZH2) is central to organismal aging. Here, we investigated the role of EZH2 in the aging-related loss of ICC/ICC-SC. METHODS klotho mice, a model of accelerated aging, were treated with the most clinically advanced EZH2 inhibitor, EPZ6438 (tazemetostat; 160 mg/kg intraperitoneally twice a day for 3 weeks). Gastric ICC were analyzed by Western blotting and immunohistochemistry. ICC and ICC-SC were quantified by flow cytometry. Gastric slow wave activity was assessed by intracellular electrophysiology. Ezh2 was deactivated in ICC by treating KitcreERT2/+;Ezh2fl/fl mice with tamoxifen. TRP53, a key mediator of aging-related ICC loss, was induced with nutlin 3a in gastric muscle organotypic cultures and an ICC-SC line. RESULTS In klotho mice, EPZ6438 treatment mitigated the decline in the ICC growth factor KIT ligand/stem cell factor and gastric ICC. EPZ6438 also improved gastric slow wave activity and mitigated the reduced food intake and impaired body weight gain characteristic of this strain. Conditional genomic deletion of Ezh2 in Kit-expressing cells also prevented ICC loss. In organotypic cultures and ICC-SC, EZH2 inhibition prevented the aging-like effects of TRP53 stabilization on ICC/ICC-SC. CONCLUSIONS Inhibition of EZH2 with EPZ6438 mitigates aging-related ICC/ICC-SC loss and gastric motor dysfunction, improving slow wave activity and food intake in klotho mice.
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Affiliation(s)
- Negar Taheri
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Egan L Choi
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Vy Truong Thuy Nguyen
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Yuebo Zhang
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Nick M Huynh
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Todd A Kellogg
- Department of Surgery, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | | | - Tamas Ordog
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Yujiro Hayashi
- Enteric Neuroscience Program and Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota; Gastroenterology Research Unit, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine and Science, Rochester, Minnesota.
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Ni Bhraonain E, Turner J, Hannigan K, Sanders K, Cobine C. Immunohistochemical characterization of interstitial cells and their relationship to motor neurons within the mouse esophagus. RESEARCH SQUARE 2024:rs.3.rs-4474290. [PMID: 38947055 PMCID: PMC11213231 DOI: 10.21203/rs.3.rs-4474290/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Interstitial cells of Cajal (ICC) and PDGFRα+ cells regulate smooth muscle motility in the gastrointestinal (GI) tract. However, their role(s) in esophageal motility are still unclear. The mouse esophagus has traditionally been described as almost entirely skeletal muscle in nature though ICC have been identified along its entire length. The current study evaluated the distribution of skeletal and smooth muscle within the esophagus using a mouse selectively expressing eGFP in smooth muscle cells (SMCs). The relationship of SMCs to ICC and PDGFRα+ cells was also examined. SMCs declined in density in the oral direction however SMCs represented ~ 25% of the area in the distal esophagus suggesting a likeness to the transition zone observed in humans. ANO1+ intramuscular ICC (ICC-IM) were distributed along the length of the esophagus though like SMCs, declined proximally. ICC-IM were closely associated with SMCs but were also found in regions devoid of SMCs. Intramuscular and submucosal PDGFRα+ cells were densely distributed throughout the esophagus though only intramuscular PDGFRα+ cells within the LES and distal esophagus highly expressed SK3. ICC-IM and PDGFRα+ cells were closely associated with nNOS+, VIP+, VAChT+ and TH+ neurons throughout the LES and distal esophagus. GFAP+ cells resembling intramuscular enteric glia were observed within the muscle and were closely associated with ICC-IM and PDGFRα+ cells, occupying a similar location to c. These data suggest that the mouse esophagus is more similar to the human than thought previously and thus set the foundation for future functional and molecular studies using transgenic mice.
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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 PMCID: PMC11281822 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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Richardson J, Dezfuli G, Mangel AW, Gillis RA, Vicini S, Sahibzada N. CNS sites controlling the gastric pyloric sphincter: Neuroanatomical and functional study in the rat. J Comp Neurol 2023; 531:1562-1581. [PMID: 37507853 PMCID: PMC10430764 DOI: 10.1002/cne.25530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 05/25/2023] [Accepted: 07/09/2023] [Indexed: 07/30/2023]
Abstract
The pyloric sphincter receives parasympathetic vagal innervation from the dorsal motor nucleus of the vagus (DMV). However, little is known about its higher-order neurons and the nuclei that engage the DMV neurons controlling the pylorus. The purpose of the present study was twofold. First, to identify neuroanatomical connections between higher-order neurons and the DMV. This was carried out by using the transneuronal pseudorabies virus PRV-152 injected into rat pylorus torus and examining the brains of these animals for PRV labeling. Second, to identify the specific sites within the DMV that functionally control the motility and tone of the pyloric sphincter. For these studies, experiments were performed to assess the effect of DMV stimulation on pylorus activity in urethane-anesthetized male rats. A strain gauge force transducer was sutured onto the pyloric tonus to monitor tone and motility. L-glutamate (500 pmol/30 nL) was microinjected unilaterally into the rostral and caudal areas of the DMV. Data from the first study indicated that neurons labeled with PRV occurred in the DMV, hindbrain raphe nuclei, midbrain Edinger-Westphal nucleus, ventral tegmental area, lateral habenula, and arcuate nucleus. Data from the second study indicated that microinjected L-glutamate into the rostral DMV results in contraction of the pylorus blocked by intravenously administered atropine and ipsilateral vagotomy. L-glutamate injected into the caudal DMV relaxed the pylorus. This response was abolished by ipsilateral vagotomy but not by intravenously administered atropine or L-NG-nitroarginine methyl ester (L-NAME). These findings identify the anatomical and functional brain neurocircuitry involved in controlling the pyloric sphincter. Our results also show that site-specific stimulation of the DMV can differentially influence the activity of the pyloric sphincter by separate vagal nerve pathways.
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Affiliation(s)
- Janell Richardson
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Ghazaul Dezfuli
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | | | - Richard A. Gillis
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Stefano Vicini
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, D.C., USA
| | - Niaz Sahibzada
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, D.C., USA
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Mawe GM, Sanders KM, Camilleri M. Overview of the Enteric Nervous System. Semin Neurol 2023; 43:495-505. [PMID: 37562453 DOI: 10.1055/s-0043-1771466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Propulsion of contents in the gastrointestinal tract requires coordinated functions of the extrinsic nerves to the gut from the brain and spinal cord, as well as the neuromuscular apparatus within the gut. The latter includes excitatory and inhibitory neurons, pacemaker cells such as the interstitial cells of Cajal and fibroblast-like cells, and smooth muscle cells. Coordination between these extrinsic and enteric neurons results in propulsive functions which include peristaltic reflexes, migrating motor complexes in the small intestine which serve as the housekeeper propelling to the colon the residual content after digestion, and mass movements in the colon which lead to defecation.
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Affiliation(s)
- Gary M Mawe
- Department of Neurological Sciences, The University of Vermont, Burlington, Vermont
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada
| | - Michael Camilleri
- Division of Gastroenterology and Hepatology, Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Mayo Clinic, Rochester, Minnesota
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7
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Truong Thuy Nguyen V, Taheri N, Choi EL, Kellogg TA, Linden DR, Hayashi Y. Insulin-Like Growth Factor1 Preserves Gastric Pacemaker Cells and Motor Function in Aging via ERK1/2 Activation. Cell Mol Gastroenterol Hepatol 2023; 16:369-383. [PMID: 37301443 PMCID: PMC10372898 DOI: 10.1016/j.jcmgh.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 06/01/2023] [Accepted: 06/02/2023] [Indexed: 06/12/2023]
Abstract
BACKGROUND & AIMS Impaired gastric motor function in the elderly causes reduced food intake leading to frailty and sarcopenia. We previously found that aging-related impaired gastric compliance was mainly owing to depletion of interstitial cells of Cajal (ICC), pacemaker cells, and neuromodulator cells. These changes were associated with reduced food intake. Transformation-related protein 53-induced suppression of extracellular signal-regulated protein kinase (ERK)1/2 in ICC stem cell (ICC-SC) cell-cycle arrest is a key process for ICC depletion and gastric dysfunction during aging. Here, we investigated whether insulin-like growth factor 1 (IGF1), which can activate ERK in gastric smooth muscles and invariably is reduced with age, could mitigate ICC-SC/ICC loss and gastric dysfunction in klotho mice, a model of accelerated aging. METHODS Klotho mice were treated with the stable IGF1 analog LONG R3 recombinant human (rh) IGF1 (150 μg/kg intraperitoneally twice daily for 3 weeks). Gastric ICC/ICC-SC and signaling pathways were studied by flow cytometry, Western blot, and immunohistochemistry. Gastric compliance was assessed in ex vivo systems. Transformation-related protein 53 was induced with nutlin 3a and ERK1/2 signaling was activated by rhIGF-1 in the ICC-SC line. RESULTS LONG R3 rhIGF1 treatment prevented reduced ERK1/2 phosphorylation and gastric ICC/ICC-SC decrease. LONG R3 rhIGF1 also mitigated the reduced food intake and impaired body weight gain. Improved gastric function by LONG R3 rhIGF1 was verified by in vivo systems. In ICC-SC cultures, rhIGF1 mitigated nutlin 3a-induced reduced ERK1/2 phosphorylation and cell growth arrest. CONCLUSIONS IGF1 can mitigate age-related ICC/ICC-SC loss by activating ERK1/2 signaling, leading to improved gastric compliance and increased food intake in klotho mice.
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Affiliation(s)
- Vy Truong Thuy Nguyen
- Enteric Neuroscience Program, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota; Gastroenterology Research Unit, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Negar Taheri
- Enteric Neuroscience Program, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota; Gastroenterology Research Unit, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Egan L Choi
- Enteric Neuroscience Program, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota; Gastroenterology Research Unit, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Todd A Kellogg
- Department of Surgery, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - David R Linden
- Enteric Neuroscience Program, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Yujiro Hayashi
- Enteric Neuroscience Program, Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota; Gastroenterology Research Unit, Mayo Clinic College of Medicine and Science, Rochester, Minnesota.
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Meng SJ, Fan MQ, Qian JS, Zhang JW, Xu HH, Zheng Y, Zhao WQ, Shan LT, Huang JF. An Innovative Model of ISS-Based Multiple Fractures and Gastrointestinal Dysfunction Related to c-Kit Protein Expression on Interstitial Cells of Cajal. Orthop Surg 2023; 15:1325-1332. [PMID: 36919913 PMCID: PMC10157708 DOI: 10.1111/os.13599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 08/01/2022] [Accepted: 10/24/2022] [Indexed: 03/16/2023] Open
Abstract
OBJECTIVE Gastrointestinal dysfunction seriously affects the prognosis and quality of life of patients with multiple fractures. However, experimental evidence of this relationship is lacking. Here we describe a newly developed mouse model of postoperative gastrointestinal dysfunction after multiple fractures. METHODS Trauma severity was assessed using the injury severity score (ISS). Based on the ISS, a multiple fracture model was established in mice as follows: limb fractures with pelvic fractures and multiple rib fractures; limb fractures with multiple rib fractures; closed fracture of both forelegs with pelvic fracture and rib fractures; closed limb fractures; limb fracture with pelvic fracture; spinal fractures; hind leg fractures with pelvic fractures; pelvic fracture with multiple rib fractures; closed fracture of both fore legs with pelvic fracture; and closed fracture of both fore legs with multiple rib fractures. In each model group, gastrointestinal motility was assayed and the histopathology of the small intestine was examined. Western blot and immunohistochemical analyses of jejunal tissue were performed to detect c-kit protein expression, the level of which was compared with that of a control group. The results of ANOVA are expressed as mean ± standard deviation. RESULTS In mice with multiple fractures, food intake was greatly reduced, consistent with histopathological evidence of an injured intestinal epithelium. The jejunal tissue of mice in groups a, c, f, and h was characterized by extensively necrotic and exfoliated intestinal mucosal epithelium and inflammatory cell infiltration in the lamina propria. In the gastrointestinal function assay, gastrointestinal motility was significantly reduced in groups a, b, c, f, and g; these group also had a higher ISS (p < 0.01). The expression of c-kit protein in groups with gastrointestinal dysfunction was significantly up-regulated (p < 0.001) compared with the control group. The close correlation between c-kit expression and the ISS indicated an influence of trauma severity on gastrointestinal motility. CONCLUSION Gastrointestinal dysfunction after multiple fractures was successfully reproduced in a mouse model. In these mice, c-kit expression correlated with gastrointestinal tissue dysfunction and might serve as a therapeutic target.
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Affiliation(s)
- Shi-Jie Meng
- The First Clinical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Meng-Qiang Fan
- The First Clinical College, Zhejiang Chinese Medical University, Hangzhou, China.,Department of Orthopaedics & Traumatology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Jian-Sheng Qian
- The Third Clinical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jing-Wen Zhang
- Research and Development Department, Cell Resource Bank and Integrated Cell Preparation Center of Xiaoshan District, Hangzhou, China
| | - Hui-Hui Xu
- The First Clinical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yang Zheng
- The First Clinical College, Zhejiang Chinese Medical University, Hangzhou, China.,Department of Orthopaedics & Traumatology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Wei-Qiang Zhao
- The First Clinical College, Zhejiang Chinese Medical University, Hangzhou, China.,Department of Orthopaedics & Traumatology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Le-Tian Shan
- The First Clinical College, Zhejiang Chinese Medical University, Hangzhou, China.,Department of Orthopaedics & Traumatology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Jie-Feng Huang
- The First Clinical College, Zhejiang Chinese Medical University, Hangzhou, China.,Department of Orthopaedics & Traumatology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
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Yagasaki R, Shikaya Y, Kawachi T, Inaba M, Takase Y, Takahashi Y. Newly raised anti-c-Kit antibody visualizes morphology of interstitial cells of Cajal in the developing gut of chicken embryos. Dev Growth Differ 2022; 64:446-454. [PMID: 36069474 DOI: 10.1111/dgd.12808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 11/28/2022]
Abstract
The gut peristaltic movement, a wave-like propagation of a local contraction, is important for the transportation and digestion of ingested materials. Among three types of cells, the enteric nervous system (ENS), smooth muscle cells, and interstitial cells of Cajal (ICCs), the ICCs have been thought to act as a pacemaker, and therefore it is important to decipher the cellular functions of ICCs for the understanding of gut peristalsis. c-Kit, a tyrosine kinase receptor, has widely been used as a marker for ICCs. Most studies with ICCs have been conducted in mammals using commercially available anti-c-Kit antibody. Recently, the chicken embryonic gut has emerged as a powerful model to study the gut peristalsis. However, since the anti-c-Kit antibody for mammals does not work for chickens, cellular mechanisms by which ICCs are regulated have largely been unexplored. Here, we report a newly raised polyclonal antibody against the chicken c-Kit protein. The specificity of the antibody was validated by both Western blotting analyses and immunocytochemistry. Co-immunostaining with the new antibody and anti-α smooth muscle actin (αSMA) antibody successfully visualized ICCs in the chicken developing hindgut in the circular muscle- and longitudinal muscle layers: as previously shown in mice, common progenitors of ICCs and smooth muscle cells at early stages were double positive for αSMA and c-Kit, and at later stages, differentiated ICCs and smooth muscle cells exhibited only c-Kit and αSMA, respectively. A novel ICC population was also found that radially extended from the submucosal layer to circular muscle layer. Furthermore, the new antibody delineated individual ICCs in a cleared hindgut. The antibody newly developed in this study will facilitate the study of peristaltic movement in chicken embryos.
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Affiliation(s)
- Rei Yagasaki
- Department of Zoology, Graduate School of Science, Kyoto University Sakyo-ku, Kyoto
| | - Yuuki Shikaya
- Department of Zoology, Graduate School of Science, Kyoto University Sakyo-ku, Kyoto
| | - Teruaki Kawachi
- Department of Zoology, Graduate School of Science, Kyoto University Sakyo-ku, Kyoto
| | - Masafumi Inaba
- Department of Zoology, Graduate School of Science, Kyoto University Sakyo-ku, Kyoto
| | - Yuta Takase
- Department of Zoology, Graduate School of Science, Kyoto University Sakyo-ku, Kyoto
| | - Yoshiko Takahashi
- Department of Zoology, Graduate School of Science, Kyoto University Sakyo-ku, Kyoto
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10
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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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11
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Filho FC, Silva JDP, Petri C, Almendra JSL, de Sousa ÍA, Cavalcanti SMG, Silva BA, Formiga Melo MF, Cavalcanti PMDS. Pharmacological evidence that GABA-induced relaxation of rat proximal duodenum longitudinal muscle depends on NKCC cotransporter activity and Ca 2+ influx. Can J Physiol Pharmacol 2022; 100:728-740. [PMID: 35880679 DOI: 10.1139/cjpp-2021-0639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter in adult central nervous system (CNS) synapses, but it excites immature CNS neurons as well as neurons in the myenteric plexus. The present work aimed to determine whether GABA-induced nonadrenergic, noncholinergic (NANC) neuronal-mediated relaxation of the rat duodenum is dependent on the activity of Na+ K+ Cl- cotransporters (NKCC) and requires calcium influx. In the presence of guanethidine (3 µmol/L), atropine (3 µmol/L), and indomethacin (1 µmol/L), relaxations induced by GABA (100 µmol/L), KCl (5-10 mmol/L) and electrical field stimulation (1-8 Hz, 2 ms, 60 V), but not those induced by bradykinin (10-100 nmol/L) were abolished by lidocaine (300 µmol/L). However, only GABA-induced relaxations were reduced in a concentration-dependent manner by the NKCC1/2 inhibitors bumetanide (0.1-1 µmol/L) and furosemide (1-10 µmol/L). GABA-induced NANC neuronal relaxation was abolished by bicuculline (30 µmol/L) and inhibited by N-nitroarginine methyl ester (l-NAME, 300 µmol/L). The ω-conotoxin GVIA (1 µmol/L), which acts exclusively on neuronal CaV2 channels, but not on smooth muscle voltage-gated Ca2+ CaV1 channels, and nonselective blockers of these channels (verapamil 100 nmol/L and ruthenium red 10 µmol/L), reduced GABA-induced relaxations. These results showed that the activation of GABAA receptors induces NANC nitrergic neuronal relaxations in the rat duodenum, which depend on NKCC activity and CaV2 channel activation, suggesting that this phenomenon results from neuronal depolarization promoted by Cl- efflux through GABAA receptors, with subsequent Ca2+ influx and nitric oxide release.
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Affiliation(s)
- Francisco Chagas Filho
- Biophysics and Physiology Department, 64049-550, Health Sciences Center, Federal University of Piauí, Teresina, Piauí, Brazil
| | - Janyerson Dannys Pereira Silva
- Biophysics and Physiology Department, 64049-550, Health Sciences Center, Federal University of Piauí, Teresina, Piauí, Brazil
| | - Caio Petri
- Biophysics and Physiology Department, 64049-550, Health Sciences Center, Federal University of Piauí, Teresina, Piauí, Brazil
| | - João Santos Lima Almendra
- Biophysics and Physiology Department, 64049-550, Health Sciences Center, Federal University of Piauí, Teresina, Piauí, Brazil
| | - Ícaro Araújo de Sousa
- Biophysics and Physiology Department, 64049-550, Health Sciences Center, Federal University of Piauí, Teresina, Piauí, Brazil
| | | | - Bagnólia A Silva
- Pharmacological Sciences Department, 58051-900, Health Sciences Center, Federal University of Paraíba, João Pessoa, Paraíba, Brazil
| | - Margareth Fátima Formiga Melo
- Pharmacological Sciences Department, 58051-900, Health Sciences Center, Federal University of Paraíba, João Pessoa, Paraíba, Brazil
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12
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Moon SB, Hwang SJ, Baker S, Kim M, Sasse K, Koh SD, Sanders KM, Ward SM. Changes in interstitial cells and gastric excitability in a mouse model of sleeve gastrectomy. PLoS One 2022; 17:e0269909. [PMID: 35737727 PMCID: PMC9223402 DOI: 10.1371/journal.pone.0269909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/31/2022] [Indexed: 11/18/2022] Open
Abstract
Obesity is a critical risk factor of several life-threatening diseases and the prevalence in adults has dramatically increased over the past ten years. In the USA the age-adjusted prevalence of obesity in adults was 42.4%, i.e., with a body mass index (BMI, weight (kg)/height (m)2) that exceeds 30 kg/m2. Obese individuals are at the higher risk of obesity-related diseases, co-morbid conditions, lower quality of life, and increased mortality more than those in the normal BMI range i.e., 18.5–24.9 kg/m2. Surgical treatment continues to be the most efficient and scientifically successful treatment for obese patients. Sleeve gastrectomy or vertical sleeve gastrectomy (VSG) is a relatively new gastric procedure to reduce body weight but is now the most popular bariatric operation. To date there have been few studies examining the changes in the cellular components and pacemaker activity that occur in the gastric wall following VSG and whether normal gastric activity recovers following VSG. In the present study we used a murine model to investigate the chronological changes of gastric excitability including electrophysiological, molecular and morphological changes in the gastric musculature following VSG. There is a significant disruption in specialized interstitial cells of Cajal in the gastric antrum following sleeve gastrectomy. This is associated with a loss of gastric pacemaker activity and post-junctional neuroeffector responses. Over a 4-month recovery period there was a gradual return in interstitial cells of Cajal networks, pacemaker activity and neural responses. These data describe for the first time the changes in gastric interstitial cells of Cajal networks, pacemaker activity and neuroeffector responses and the time-dependent recovery of ICC networks and normalization of motor activity and neural responses following VSG.
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Affiliation(s)
- Suk Bae Moon
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, Nevada, United States of America
| | - Sung Jin Hwang
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, Nevada, United States of America
| | - Sal Baker
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, Nevada, United States of America
| | - Minkyung Kim
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, Nevada, United States of America
| | - Kent Sasse
- Sasse Surgical Associates, Reno, Nevada, United States of America
| | - Sang Don Koh
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, Nevada, United States of America
| | - Kenton M. Sanders
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, Nevada, United States of America
| | - Sean M. Ward
- Department of Physiology & Cell Biology, Reno School of Medicine, University of Nevada, Reno, Nevada, United States of America
- * E-mail:
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13
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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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14
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Koh SD, Drumm BT, Lu H, Kim HJ, Ryoo SB, Kim HU, Lee JY, Rhee PL, Wang Q, Gould TW, Heredia D, Perrino BA, Hwang SJ, Ward SM, Sanders KM. Propulsive colonic contractions are mediated by inhibition-driven poststimulus responses that originate in interstitial cells of Cajal. Proc Natl Acad Sci U S A 2022; 119:e2123020119. [PMID: 35446689 PMCID: PMC9170151 DOI: 10.1073/pnas.2123020119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/17/2022] [Indexed: 12/23/2022] Open
Abstract
The peristaltic reflex is a fundamental behavior of the gastrointestinal (GI) tract in which mucosal stimulation activates propulsive contractions. The reflex occurs by stimulation of intrinsic primary afferent neurons with cell bodies in the myenteric plexus and projections to the lamina propria, distribution of information by interneurons, and activation of muscle motor neurons. The current concept is that excitatory cholinergic motor neurons are activated proximal to and inhibitory neurons are activated distal to the stimulus site. We found that atropine reduced, but did not block, colonic migrating motor complexes (CMMCs) in mouse, monkey, and human colons, suggesting a mechanism other than one activated by cholinergic neurons is involved in the generation/propagation of CMMCs. CMMCs were activated after a period of nerve stimulation in colons of each species, suggesting that the propulsive contractions of CMMCs may be due to the poststimulus excitation that follows inhibitory neural responses. Blocking nitrergic neurotransmission inhibited poststimulus excitation in muscle strips and blocked CMMCs in intact colons. Our data demonstrate that poststimulus excitation is due to increased Ca2+ transients in colonic interstitial cells of Cajal (ICC) following cessation of nitrergic, cyclic guanosine monophosphate (cGMP)-dependent inhibitory responses. The increase in Ca2+ transients after nitrergic responses activates a Ca2+-activated Cl− conductance, encoded by Ano1, in ICC. Antagonists of ANO1 channels inhibit poststimulus depolarizations in colonic muscles and CMMCs in intact colons. The poststimulus excitatory responses in ICC are linked to cGMP-inhibited cyclic adenosine monophosphate (cAMP) phosphodiesterase 3a and cAMP-dependent effects. These data suggest alternative mechanisms for generation and propagation of CMMCs in the colon.
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Affiliation(s)
- Sang Don Koh
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Bernard T. Drumm
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Hongli Lu
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Hyun Jin Kim
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Seung-Bum Ryoo
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Heung-Up Kim
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Ji Yeon Lee
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Poong-Lyul Rhee
- Division of Gastroenterology, Department of Medicine, Sungkyunkwan University School of Medicine, Samsung Medical Center, Gangnam-Gu, Seoul, Korea 135-710
| | - Qianqian Wang
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Thomas W. Gould
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Dante Heredia
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Brian A. Perrino
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Sung Jin Hwang
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Sean M. Ward
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
| | - Kenton M. Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557
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15
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Ni B, Li Q, Zhuang C, Huang P, Xia X, Yang L, Ma X, Huang C, Zhao W, Tu L, Shen Y, Zhu C, Zhang Z, Zhao E, Wang M, Cao H. The nerve-tumour regulatory axis GDNF-GFRA1 promotes tumour dormancy, imatinib resistance and local recurrence of gastrointestinal stromal tumours by achieving autophagic flux. Cancer Lett 2022; 535:215639. [PMID: 35288241 DOI: 10.1016/j.canlet.2022.215639] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/01/2022] [Accepted: 03/09/2022] [Indexed: 11/17/2022]
Abstract
Complete surgical resection, accessible therapeutic targets and effective tyrosine kinase inhibitors (TKIs) have not completely cured gastrointestinal stromal tumours (GISTs), with most patients suffering from residual tumours and recurrence. The existence of nerve infiltration in GIST provides a way for tumour cells to escape local resection and systemic targeted therapy, which may challenge the previous understanding of its behaviour patterns and inspire the development of more radical excision and more precise targeted therapy. Moreover, tumour dormancy has emerged as a major cause of drug resistance and tumour relapse. Among these pathways, the nerve-tumour regulatory axis GDNF-GFRA1 is activated in GISTs, assists tumour cells in achieving dormancy and protects them from apoptosis under environmental stress by enhancing autophagic flux. The concrete mechanism is that the GDNF-regulating interaction between GFRA1 and the lysosomal calcium channel MCOLN1 activates Ca2+-dependent TFEB signalling. Activated TFEB transcriptionally regulates intracellular lysosome levels, which could achieve feedback upregulation of cellular autophagy flux during TKI treatment. This dormancy-transition axis fills parts of the mechanistic vacancy before the onset of secondary mutations, and strategies for TKIs combined with targeting GFRA1-dependent autophagy have distinct promise as prospective clinical therapies.
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Affiliation(s)
- Bo Ni
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qing Li
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chun Zhuang
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Peiqi Huang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiang Xia
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Linxi Yang
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xinli Ma
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Huang
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenyi Zhao
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lin Tu
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yanying Shen
- Department of Pathology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chunchao Zhu
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zizhen Zhang
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Enhao Zhao
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Ming Wang
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Hui Cao
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Mischopoulou M, D’Ambrosio M, Bigagli E, Luceri C, Farrugia G, Cipriani G. Role of Macrophages and Mast Cells as Key Players in the Maintenance of Gastrointestinal Smooth Muscle Homeostasis and Disease. Cell Mol Gastroenterol Hepatol 2022; 13:1849-1862. [PMID: 35245688 PMCID: PMC9123576 DOI: 10.1016/j.jcmgh.2022.02.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 12/18/2022]
Abstract
The gut contains the largest macrophage pool in the body, with populations of macrophages residing in the mucosa and muscularis propria of the gastrointestinal (GI) tract. Muscularis macrophages (MMs), which are located within the muscularis propria, interact with cells essential for GI function, such as interstitial cells of Cajal, enteric neurons, smooth muscle cells, enteric glia, and fibroblast-like cells, suggesting that these immune cells contribute to several aspects of GI function. This review focuses on the latest insights on the factors contributing to MM heterogeneity and the functional interaction of MMs with other cell types essential for GI function. This review integrates the latest findings on macrophages in other organs with increasing knowledge of MMs to better understand their role in a healthy and diseased gut. We describe the factors that contribute to (muscularis macrophage) MM heterogeneity, and the nature of MM interactions with cells regulating GI function. Finally, we also describe the increasing evidence suggesting a critical role of another immune cell type, the mast cell, in normal and diseased GI physiology.
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Affiliation(s)
| | - Mario D’Ambrosio
- Section of Pharmacology and Toxicology, Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | - Elisabetta Bigagli
- Section of Pharmacology and Toxicology, Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | - Cristina Luceri
- Section of Pharmacology and Toxicology, Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | | | - Gianluca Cipriani
- Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,Correspondence Address correspondence to: Gianluca Cipriani, PhD, Enteric Neuroscience Program, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905. fax: (507) 284-0266.
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Analysis of Regional Variations of the Interstitial Cells of Cajal in the Murine Distal Stomach Informed by Confocal Imaging and Machine Learning Methods. Cell Mol Bioeng 2022; 15:193-205. [PMID: 35401841 PMCID: PMC8938532 DOI: 10.1007/s12195-021-00716-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/24/2021] [Indexed: 01/05/2023] Open
Abstract
Introduction The network of Interstitial Cells of Cajal (ICC) plays a plethora of key roles in maintaining, coordinating, and regulating the contractions of the gastrointestinal (GI) smooth muscles. Several GI functional motility disorders have been associated with ICC degradation. This study extended a previously reported 2D morphological analysis and applied it to 3D spatial quantification of three different types of ICC networks in the distal stomach guided by confocal imaging and machine learning methods. The characterization of the complex changes in spatial structure of the ICC network architecture contributes to our understanding of the roles that different types of ICC may play in post-prandial physiology, pathogenesis, and/or amelioration of GI dsymotility- bridging structure and function. Methods A validated classification method using Trainable Weka Segmentation was applied to segment the ICC from a confocal dataset of the gastric antrum of a transgenic mouse, followed by structural analysis of the segmented images. Results The machine learning model performance was compared to manually segmented subfields, achieving an area under the receiver-operating characteristic (AUROC) of 0.973 and 0.995 for myenteric ICC (ICC-MP; n = 6) and intramuscular ICC (ICC-IM; n = 17). The myenteric layer in the distal antrum increased in thickness (from 14.5 to 34 μm) towards the lesser curvature, whereas the thickness decreased towards the lesser curvature in the proximal antrum (17.7 to 9 μm). There was an increase in ICC-MP volume from proximal to distal antrum (406,960 ± 140,040 vs. 559,990 ± 281,000 μm3; p = 0.000145). The % of ICC volume was similar for ICC-LM and for ICC-CM between proximal (3.6 ± 2.3% vs. 3.1 ± 1.2%; p = 0.185) and distal antrum (3.2 ± 3.9% vs. 2.5 ± 2.8%; p = 0.309). The average % volume of ICC-MP was significantly higher than ICC-IM at all points throughout sample (p < 0.0001). Conclusions The segmentation and analysis methods provide a high-throughput framework of investigating the structural changes in extended ICC networks and their associated physiological functions in animal models.
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Abstract
Gastroparesis is characterized by symptoms suggestive of, and objective evidence of, delayed gastric emptying in the absence of mechanical obstruction. This review addresses the normal emptying of solids and liquids from the stomach and details the myogenic and neuromuscular control mechanisms, including the specialized function of the pyloric sphincter, that result in normal emptying, based predominantly on animal research. A clear understanding of fundamental mechanisms is necessary to comprehend derangements leading to gastroparesis, and additional research on human gastric muscles is needed. The section on pathophysiology of gastroparesis considers neuromuscular diseases that affect nonsphincteric gastric muscle, disorders of the extrinsic neural control, and pyloric dysfunction that lead to gastroparesis. The potential cellular basis for gastroparesis is attributed to the effects of oxidative stress and inflammation, with increased pro-inflammatory and decreased resident macrophages, as observed in full-thickness biopsies from patients with gastroparesis. Predominant diagnostic tests involving measurements of gastric emptying, the use of a functional luminal imaging probe, and high-resolution antral duodenal manometry in characterizing the abnormal motor functions at the gastroduodenal junction are discussed. Management is based on supporting nutrition; dietary interventions, including the physical reduction in particle size of solid foods; pharmacological agents, including prokinetics and anti-emetics; and interventions such as gastric electrical stimulation and pyloromyotomy. These are discussed briefly, and comment is added on the potential for individualized treatments in the future, based on optimal gastric emptying measurement and objective documentation of the underlying pathophysiology causing the gastroparesis.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota.
| | - Kenton M. Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV
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19
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Otsuka Y, Bai X, Tanaka Y, Ihara E, Chinen T, Ogino H, Ogawa Y. Involvement of interstitial cells of Cajal in nicotinic acetylcholine receptor-induced relaxation of the porcine lower esophageal sphincter. Eur J Pharmacol 2021; 910:174491. [PMID: 34506779 DOI: 10.1016/j.ejphar.2021.174491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 08/27/2021] [Accepted: 09/03/2021] [Indexed: 11/15/2022]
Abstract
The interstitial cells of Cajal (ICCs) play an important role in coordinated gastrointestinal motility. The present study aimed to elucidate whether or how ICCs are involved in the lower esophageal sphincter (LES) relaxation induced by stimulation of the nicotinic acetylcholine receptor. The application of 1,1-dimethyl-4-phenyl-piperazinium (DMPP; a nicotinic acetylcholine receptor agonist) induced a transient relaxation in the circular smooth muscle of the porcine LES. DMPP-induced relaxation was abolished by not only 1 μM tetrodotoxin but also the inhibition of ICC activity by pretreatment with 100 μM carbenoxolone (a gap junction inhibitor), pretreatment with 100 μM CaCCinh-A01 (an anoctamin-1 blocker acting as a calcium-activated chloride channel inhibitor), and pretreatment with Cl--free solution. However, pretreatment with 100 μM Nω-nitro-L-arginine methyl ester had little effect on DMPP-induced relaxation. Furthermore, DMPP-induced relaxation was inhibited by pretreatment with 1 mM suramin, a purinergic P2 receptor antagonist, but not by 1 μM VIP (6-28), a vasoactive intestinal peptide (VIP) receptor antagonist. Stimulation of the purinergic P2 receptor with adenosine triphosphate (ATP) induced relaxation, which was abolished by the inhibition of ICC activity by pretreatment with CaCCinh-A01. In conclusion, membrane hyperpolarization of the ICCs via the activation of anoctamin-1 plays a central role in DMPP-induced relaxation. ATP may be a neurotransmitter for inhibitory enteric neurons, which stimulate the ICCs. The ICCs act as the interface of neurotransmission of nicotinic acetylcholine receptor in order to induce LES relaxation.
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Affiliation(s)
- Yoshihiro Otsuka
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Xiaopeng Bai
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yoshimasa Tanaka
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Eikichi Ihara
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan; Department of Gastroenterology and Metabolism, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
| | - Takatoshi Chinen
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Haruei Ogino
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yoshihiro Ogawa
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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20
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Mah SA, Avci R, Du P, Vanderwinden JM, Cheng LK. Antral Variation of Murine Gastric Pacemaker Cells Informed by Confocal Imaging and Machine Learning Methods. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:3105-3108. [PMID: 34891899 DOI: 10.1109/embc46164.2021.9630341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The Interstitial Cells of Cajal (ICC) are specialized gastrointestinal (GI) pacemaker cells that generate and actively propagate electrophysiological events called slow waves. Slow waves regulate the GI motility necessary for digestion. Several functional GI motility disorders have been associated with depletion in the ICC. In this study, a validated Fast Random Forest (FRF) classification method using Trainable WEKA Segmentation for segmenting the networks of ICC was applied to confocal microscopy images of a whole mount tissue from the distal antrum of a mouse stomach (583 × 3,376 × 133 μm3, parcellated into 24 equal image stacks). The FRF model performance was compared to 6 manually segmented subflelds and produced an area under the receiver-operating characteristic (AUROC) of 0.95. Structural variations of ICC network in the longitudinal muscle (ICC-LM) and myenteric plexus (ICC-MP) were quantified. The average volume of ICC-MP was significantly higher than ICC-LM at any point throughout the antral tissue sampled. There was a pronounced decline of up to 80% in ICC-LM (from 3,705 μm3 to 716 μm3) over a distance of 279.3 μm, that eventually diminished towards the distal antrum. However, an inverse relationship was observed in ICC-MP with an overall increase of up to 157% (from 59,100 μm3 to 151,830 μm3) over a distance of approximately 2 mm that proceeds towards the distal antrum.
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21
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Huizinga JD, Hussain A, Chen JH. Interstitial cells of Cajal and human colon motility in health and disease. Am J Physiol Gastrointest Liver Physiol 2021; 321:G552-G575. [PMID: 34612070 DOI: 10.1152/ajpgi.00264.2021] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Our understanding of human colonic motility, and autonomic reflexes that generate motor patterns, has increased markedly through high-resolution manometry. Details of the motor patterns are emerging related to frequency and propagation characteristics that allow linkage to interstitial cells of Cajal (ICC) networks. In studies on colonic motor dysfunction requiring surgery, ICC are almost always abnormal or significantly reduced. However, there are still gaps in our knowledge about the role of ICC in the control of colonic motility and there is little understanding of a mechanistic link between ICC abnormalities and colonic motor dysfunction. This review will outline the various ICC networks in the human colon and their proven and likely associations with the enteric and extrinsic autonomic nervous systems. Based on our extensive knowledge of the role of ICC in the control of gastrointestinal motility of animal models and the human stomach and small intestine, we propose how ICC networks are underlying the motor patterns of the human colon. The role of ICC will be reviewed in the autonomic neural reflexes that evoke essential motor patterns for transit and defecation. Mechanisms underlying ICC injury, maintenance, and repair will be discussed. Hypotheses are formulated as to how ICC dysfunction can lead to motor abnormalities in slow transit constipation, chronic idiopathic pseudo-obstruction, Hirschsprung's disease, fecal incontinence, diverticular disease, and inflammatory conditions. Recent studies on ICC repair after injury hold promise for future therapies.
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Affiliation(s)
- Jan D Huizinga
- Division of Gastroenterology, Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Amer Hussain
- Division of Gastroenterology, Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Ji-Hong Chen
- Division of Gastroenterology, Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
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22
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Amberg GC, Lee JY, Koh SD, Sanders KM. Characterization of the A-type potassium current in murine gastric fundus smooth muscles. Am J Physiol Cell Physiol 2021; 321:C684-C693. [PMID: 34432539 PMCID: PMC8560387 DOI: 10.1152/ajpcell.00247.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 11/22/2022]
Abstract
Transient outward, or "A-type," currents are rapidly inactivating voltage-gated potassium currents that operate at negative membrane potentials. A-type currents have not been reported in the gastric fundus, a tonic smooth muscle. We used whole cell voltage clamp to identify and characterize A-type currents in smooth muscle cells (SMCs) isolated from murine fundus. A-type currents were robust in these cells with peak amplitudes averaging 1.5 nA at 0 mV. Inactivation was rapid with a time constant of 71 ms at 0 mV; recovery from inactivation at -80 mV was similarly rapid with a time constant of 75 ms. A-type currents in fundus were blocked by 4-aminopyridine (4-AP), flecainide, and phrixotoxin-1 (PaTX1). Remaining currents after 4-AP and PaTX1 displayed half-activation potentials that were shifted to more positive potentials and showed incomplete inactivation. Currents after tetraethylammonium (TEA) displayed half inactivation at -48.1 ± 1.0 mV. Conventional microelectrode and contractile experiments on intact fundus muscles showed that 4-AP depolarized membrane potential and increased tone under conditions in which enteric neurotransmission was blocked. These data suggest that A-type K+ channels in fundus SMCs are likely active at physiological membrane potentials, and sustained activation of A-type channels contributes to the negative membrane potentials of this tonic smooth muscle. Quantitative analysis of Kv4 expression showed that Kcnd3 was dominantly expressed in fundus SMCs. These data were confirmed by immunohistochemistry, which revealed Kv4.3-like immunoreactivity within the tunica muscularis. These observations indicate that Kv4 channels likely form the A-type current in murine fundus SMCs.
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Affiliation(s)
- Gregory C Amberg
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Ji Yeon Lee
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Sang Don Koh
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada
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23
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Ferreira A, Duarte Cruz C. The urethra in continence and sensation: Neural aspects of urethral function. Neurourol Urodyn 2021; 40:744-752. [PMID: 33604909 DOI: 10.1002/nau.24632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/11/2021] [Accepted: 01/30/2021] [Indexed: 11/08/2022]
Abstract
AIMS Traditionally, the urethra has been considered a mere conduit to guide urine from the bladder to the external side of the body. Building evidence indicates that the urethra may directly influence bladder function via mechanisms restricted to the lower urinary tract (LUT). METHODS Here, we discuss the tissue arrangement of the urethra and addressed the contribution of new paraneuronal cells to LUT function. We also briefly reviewed two frequent LUT pathologies associated with urethral dysfunction. RESULTS Continence depends on an intact and functional urethral sphincter, composed of smooth, and striated muscle fibers and regulated by somatic and autonomic fibers. Recent studies suggest the existence of an urethro-vesical reflex that also contributes to normal LUT function. Indeed, the urethral lumen is lined by a specialized epithelium, the urothelium, in the proximal urethra. In this region, recent evidence demonstrates the presence of specific paraneuronal cells, expressing the neurotransmitters acetylcholine and serotonin. These cells are in close proximity of nerve fibers coursing in the lamina propria and are able to release neurotransmitters and rapidly induce detrusor contractions, supporting the existence of an urethro-vesical crosstalk. CONCLUSION The mechanism underlying the fast communication between the urethra and thebladder are beginning to be understood and should involve the interaction between specificepithelial cells and fibres innervating the urethral wall. It is likely that this reflex should bealtered in pathological conditions, becoming an attractive therapeutic target.
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Affiliation(s)
- Ana Ferreira
- Experimental Biology Unit, Department of Biomedicine, Faculty of Medicine of Porto, University of Porto, Porto, Portugal.,Translational Neuro-Urology, Instituto de Investigação e Inovação em Saúde-i3S, Universidade do Porto, Porto, Portugal
| | - Célia Duarte Cruz
- Experimental Biology Unit, Department of Biomedicine, Faculty of Medicine of Porto, University of Porto, Porto, Portugal.,Translational Neuro-Urology, Instituto de Investigação e Inovação em Saúde-i3S, Universidade do Porto, Porto, Portugal
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24
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Drumm BT, Thornbury KD, Hollywood MA, Sergeant GP. Role of Ano1 Ca 2+-activated Cl - channels in generating urethral tone. Am J Physiol Renal Physiol 2021; 320:F525-F536. [PMID: 33554780 DOI: 10.1152/ajprenal.00520.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Urinary continence is maintained in the lower urinary tract by the contracture of urethral sphincters, including smooth muscle of the internal urethral sphincter. These contractions occlude the urethral lumen, preventing urine leakage from the bladder to the exterior. Over the past 20 years, research on the ionic conductances that contribute to urethral smooth muscle contractility has greatly accelerated. A debate has emerged over the role of interstitial cell of Cajal (ICC)-like cells in the urethra and their expression of Ca2+-activated Cl- channels encoded by anoctamin-1 [Ano1; transmembrane member 16 A (Tmem16a) gene]. It has been proposed that Ano1 channels expressed in urethral ICC serve as a source of depolarization for smooth muscle cells, increasing their excitability and contributing to tone. Although a clear role for Ano1 channels expressed in ICC is evident in other smooth muscle organs, such as the gastrointestinal tract, the role of these channels in the urethra is unclear, owing to differences in the species (rabbit, rat, guinea pig, sheep, and mouse) examined and experimental approaches by different groups. The importance of clarifying this situation is evident as effective targeting of Ano1 channels may lead to new treatments for urinary incontinence. In this review, we summarize the key findings from different species on the role of ICC and Ano1 channels in urethral contractility. Finally, we outline proposals for clarifying this controversial and important topic by addressing how cell-specific optogenetic and inducible cell-specific genetic deletion strategies coupled with advances in Ano1 channel pharmacology may clarify this area in future studies.NEW & NOTEWORTHY Studies from the rabbit have shown that anoctamin-1 (Ano1) channels expressed in urethral interstitial cells of Cajal (ICC) serve as a source of depolarization for smooth muscle cells, increasing excitability and tone. However, the role of urethral Ano1 channels is unclear, owing to differences in the species examined and experimental approaches. We summarize findings from different species on the role of urethral ICC and Ano1 channels in urethral contractility and outline proposals for clarifying this topic using cell-specific optogenetic approaches.
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Affiliation(s)
- Bernard T Drumm
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Keith D Thornbury
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Mark A Hollywood
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Gerard P Sergeant
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
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25
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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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26
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Durnin L, Kurahashi M, Sanders KM, Mutafova-Yambolieva VN. Extracellular metabolism of the enteric inhibitory neurotransmitter β-nicotinamide adenine dinucleotide (β-NAD) in the murine colon. J Physiol 2020; 598:4509-4521. [PMID: 32735345 DOI: 10.1113/jp280051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS β-Nicotinamide adenine dinucleotide (β-NAD) is a key inhibitory neurotransmitter in the colon. The neuroeffector junction in the gut consists of enteric motor neurons and SIP syncytium, including smooth muscle cells (SMCs), interstitial cells of Cajal (ICC), and cells expressing platelet-derived growth factor receptor α (PDGFRα+ cells). Measuring metabolism of 1,N6 -etheno-NAD (eNAD) in colonic tunica muscularis and in SMCs, ICC and PDGFRα+ cells with HPLC-FLD, we report that (1) in tissues, eNAD is degraded to eADP-ribose, eAMP and e-adenosine (eADO) by CD38, ENPP1 and NT5E, (2) with SMCs and PDGFRα+ cells, eNAD is metabolized to eADO by ENPP1 and NT5E, (3) eNAD is not metabolized by ICC, (4) NT5E is expressed chiefly by SMCs and moderately by PDGFRα+ cells, (5) SIP cells are not the primary location of CD38. These data argue that the duration and strength of purinergic neurotransmission can be modulated by targeting multiple enzymes with specialized cellular distribution in the colon. ABSTRACT Prior studies suggest that β-nicotinamide adenine dinucleotide (β-NAD) is an important inhibitory motor neurotransmitter in the enteric nervous system. Metabolism of β-NAD at the neuroeffector junction (NEJ) is likely to be necessary for terminating inhibitory neurotransmission and may also produce bioactive metabolites. The enteric NEJ consists of enteric neurons and postjunctional cells of the SIP syncytium, including smooth muscle cells (SMCs), interstitial cells of Cajal (ICC), and cells expressing platelet-derived growth factor receptor α (PDGFRα+ cells). We examined possible specialized functions of the NEJ in β-NAD metabolism by determining the degradation of 1,N6 -etheno-NAD (eNAD) in colonic tunica muscularis of wild-type, Cd38-/- , Nt5e-/- , Enpp1-/- and Cd38-/- /Nt5e-/- mice and in SIP cells from mice expressing cell-specific fluorescent reporters purified by fluorescence activated cell sorting (FACS). We measured eNAD and its metabolites eADP-ribose (eADPR), eAMP and e-adenosine (eADO) from tissues and sorted SIP cells using liquid chromatography. eNAD exposed to colonic muscularis of wild-type mice produced eADPR, eAMP and eADO. CD38 mediated the conversion of eNAD to eADPR, whereas ENPP1 mediated degradation of eNAD and eADPR to eAMP. NT5E (aka CD73) was the primary enzyme forming eADO from eAMP. PDGFRα+ cells and SMCs were involved in production of eADO from eNAD, and ICC were not involved in extracellular metabolism of eNAD. CD38 mediated the eNAD metabolism in whole tissues, but CD38 did not appear to be functionally expressed by SMCs or ICC. NT5E was expressed in SMCs > PDGFRα+ cells. Our data show that extracellular metabolism of β-NAD in the colon is mediated by multiple enzymes with cell-specific expression.
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Affiliation(s)
- Leonie Durnin
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Masaaki Kurahashi
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
| | - Violeta N Mutafova-Yambolieva
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, 1664 North Virginia Street, Reno, NV, 89557, USA
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27
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Foong D, Zhou J, Zarrouk A, Ho V, O’Connor MD. Understanding the Biology of Human Interstitial Cells of Cajal in Gastrointestinal Motility. Int J Mol Sci 2020; 21:ijms21124540. [PMID: 32630607 PMCID: PMC7352366 DOI: 10.3390/ijms21124540] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/19/2020] [Accepted: 06/23/2020] [Indexed: 12/11/2022] Open
Abstract
Millions of patients worldwide suffer from gastrointestinal (GI) motility disorders such as gastroparesis. These disorders typically include debilitating symptoms, such as chronic nausea and vomiting. As no cures are currently available, clinical care is limited to symptom management, while the underlying causes of impaired GI motility remain unaddressed. The efficient movement of contents through the GI tract is facilitated by peristalsis. These rhythmic slow waves of GI muscle contraction are mediated by several cell types, including smooth muscle cells, enteric neurons, telocytes, and specialised gut pacemaker cells called interstitial cells of Cajal (ICC). As ICC dysfunction or loss has been implicated in several GI motility disorders, ICC represent a potentially valuable therapeutic target. Due to their availability, murine ICC have been extensively studied at the molecular level using both normal and diseased GI tissue. In contrast, relatively little is known about the biology of human ICC or their involvement in GI disease pathogenesis. Here, we demonstrate human gastric tissue as a source of primary human cells with ICC phenotype. Further characterisation of these cells will provide new insights into human GI biology, with the potential for developing novel therapies to address the fundamental causes of GI dysmotility.
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Affiliation(s)
- Daphne Foong
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (D.F.); (J.Z.); (V.H.)
| | - Jerry Zhou
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (D.F.); (J.Z.); (V.H.)
| | - Ali Zarrouk
- Campbelltown Private Hospital, Campbelltown, NSW 2560, Australia;
| | - Vincent Ho
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (D.F.); (J.Z.); (V.H.)
- Campbelltown Private Hospital, Campbelltown, NSW 2560, Australia;
| | - Michael D. O’Connor
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (D.F.); (J.Z.); (V.H.)
- Correspondence:
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28
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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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29
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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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Wang YB, de Lartigue G, Page AJ. Dissecting the Role of Subtypes of Gastrointestinal Vagal Afferents. Front Physiol 2020; 11:643. [PMID: 32595525 PMCID: PMC7300233 DOI: 10.3389/fphys.2020.00643] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/20/2020] [Indexed: 12/22/2022] Open
Abstract
Gastrointestinal (GI) vagal afferents convey sensory signals from the GI tract to the brain. Numerous subtypes of GI vagal afferent have been identified but their individual roles in gut function and feeding regulation are unclear. In the past decade, technical approaches to selectively target vagal afferent subtypes and to assess their function has significantly progressed. This review examines the classification of GI vagal afferent subtypes and discusses the current available techniques to study vagal afferents. Investigating the distribution of GI vagal afferent subtypes and understanding how to access and modulate individual populations are essential to dissect their fundamental roles in the gut-brain axis.
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Affiliation(s)
- Yoko B Wang
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Guillaume de Lartigue
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, United States.,Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL, United States
| | - Amanda J Page
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes and Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, SA, Australia
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31
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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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32
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Kikuchi K, Noh H, Numayama-Tsuruta K, Ishikawa T. Mechanical roles of anterograde and retrograde intestinal peristalses after feeding in a larval fish ( Danio rerio). Am J Physiol Gastrointest Liver Physiol 2020; 318:G1013-G1021. [PMID: 32281395 DOI: 10.1152/ajpgi.00165.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Transport in gut is important, not only for digestion, metabolism, and nutrient uptake, but also for microbiotic circumstance in the digestive tract; however, the effects of mixing and pumping in the intestine have not been fully clarified. Therefore, in this study, we quantitatively explored intestinal mixing and pumping, represented using a dispersion coefficient and pressure rise in zebrafish larvae, which is a model organism for vertebrate digestive studies, over time by measuring transport phenomena after feeding. Here we provide the first quantitative evidence of the roles of anterograde and retrograde intestinal peristalses in the larval fish of Danio rerio after feeding in terms of digestive pumping and mixing functions by an in vivo imaging of intestinal propagation waves in the larval intestine. Peristaltic velocities in the anterior and posterior intestines change considerably after feeding for 5 h, while the intervals and amplitudes remain almost constant. The intestinal transport is successively visualized after feeding to elimination. Moreover, the particle tracking velocimetry in the chyme leads our quantitative understanding of outstanding mixing and pumping functions in the anterior and posterior intestines by adopting physical parameters of diffusivity and pressure rise, respectively. From scaling analysis, we found that the anterior intestine maintains mixing for 5 h from feeding, whereas the posterior intestine activates gradually pumping up. These results suggest that time change of pumping and mixing functions of intestinal peristalsis could considerably influence the nutrient uptake and microbiotic circumstance in the larval fish intestine.NEW & NOTEWORTHY Transport in gut is important, not only for digestion, metabolism, and nutrient uptake, but also for microbiotic circumstance; however, hydrodynamic effects in the intestine have not been fully clarified. We provide the first quantitative evidence of the mechanical roles of anterograde and retrograde intestinal peristalses in the larval fish of Danio rerio by adopting physical parameters of diffusivity and pressure rise. The intestine transitionally regulates mixing and pumping functions by peristaltic propagations after feeding.
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Affiliation(s)
- Kenji Kikuchi
- Department of Finemechanics, Graduate School of Engineering, Tohoku University, Sendai, Japan.,Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | - Hyeongtak Noh
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | | | - Takuji Ishikawa
- Department of Finemechanics, Graduate School of Engineering, Tohoku University, Sendai, Japan.,Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
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Lisowski ZM, Sauter KA, Waddell LA, Hume DA, Pirie RS, Hudson NPH. Immunohistochemical study of morphology and distribution of CD163 +ve macrophages in the normal adult equine gastrointestinal tract. Vet Immunol Immunopathol 2020; 226:110073. [PMID: 32559524 DOI: 10.1016/j.vetimm.2020.110073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 04/07/2020] [Accepted: 05/15/2020] [Indexed: 12/20/2022]
Abstract
Intestinal macrophages are the largest group of mononuclear phagocytes in the body and play a role in intestinal innate immunity, neuroimmune interactions and maintaining intestinal homeostasis. Conversely, they also are implicated in numerous pathologies of the gastrointestinal tract, such as postoperative ileus and inflammatory bowel disease. As a result, macrophages could be potential therapeutic targets. To date, there are limited studies on the morphology and distribution of macrophages in the equine gastrointestinal tract (GIT). The aim of this study was to identify the location and abundance of resident macrophages in the equine GIT using CD163 as an immunohistochemical marker. Tissue samples were obtained post-mortem from 14 sites along the gastrointestinal tracts of 10 horses free from gastrointestinal disease; sample sites extended from the stomach to the small colon. CD163+ve cells were present in all regions of the equine GIT from stomach to small colon. CD163+ve cells were also identified in all tissue layers of the intestinal wall, namely, mucosa, submucosa, muscularis externa (ME), myenteric plexus and serosa. Consistent with a proposed function in regulation of intestinal motility, CD163+ve cells were regularly distributed within the ME, with accumulations closely associated with the myenteric plexus and effector cells such as neurons and the interstitial cells of Cajal (ICC).
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Affiliation(s)
- Zofia M Lisowski
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom.
| | - Kristin A Sauter
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Lindsey A Waddell
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - David A Hume
- Mater Research Institute-University of Queensland, Woolloongabba, QLD, Australia
| | - R Scott Pirie
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Neil P H Hudson
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
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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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Nikaki K, Sawada A, Ustaoglu A, Sifrim D. Neuronal Control of Esophageal Peristalsis and Its Role in Esophageal Disease. Curr Gastroenterol Rep 2019; 21:59. [PMID: 31760496 DOI: 10.1007/s11894-019-0728-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
PURPOSE OF REVIEW Esophageal peristalsis is a highly sophisticated function that involves the coordinated contraction and relaxation of striated and smooth muscles in a cephalocaudal fashion, under the control of central and peripheral neuronal mechanisms and a number of neurotransmitters. Esophageal peristalsis is determined by the balance of the intrinsic excitatory cholinergic, inhibitory nitrergic and post-inhibitory rebound excitatory output to the esophageal musculature. RECENT FINDINGS Dissociation of the longitudinal and circular muscle contractions characterizes different major esophageal disorders and leads to esophageal symptoms. Provocative testing during esophageal high-resolution manometry is commonly employed to assess esophageal body peristaltic reserve and underpin clinical diagnosis. Herein, we summarize the main factors that determine esophageal peristalsis and examine their role in major and minor esophageal motility disorders and eosinophilic esophagitis.
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Affiliation(s)
- K Nikaki
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, 26 Ashfield Street, Whitechapel, London, E1 2AJ, UK
| | - A Sawada
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, 26 Ashfield Street, Whitechapel, London, E1 2AJ, UK
| | - A Ustaoglu
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, 26 Ashfield Street, Whitechapel, London, E1 2AJ, UK
| | - D Sifrim
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, 26 Ashfield Street, Whitechapel, London, E1 2AJ, UK.
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36
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Liang Y, Tarique I, Vistro WA, Liu Y, Wang Z, haseeb A, Gandahi NS, Iqbal A, Wang S, An T, Yang H, Chen Q, Yang P. Age-associated changes of the intrinsic nervous system in relation with interstitial cells in the pre-weaning goat rumen. Aging (Albany NY) 2019; 11:4641-4653. [PMID: 31305258 PMCID: PMC6660047 DOI: 10.18632/aging.102076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 07/01/2019] [Indexed: 05/04/2023]
Abstract
In this study, we investigated the neural changes and their relationships with interstitial cells (ICs) in the rumen of pre-weaning goats by transmission electron microscopy, western blot and immunofluorescence (antibody: general neuronal marker-Protein Gene Product (PGP9.5)/ IC marker-vimentin). The immunofluorescence results showed that PGP9.5-positive reaction was widely distributed in neuronal soma (NS) and nerve fibre (NF). The NSs were observed in the ganglia of the myenteric plexus (MP) but not in the submucosal plexus. The mean optical density (MOD) of the whole of PGP9.5-positive nerves and the protein expression level of PGP.5 in the rumen wall both decreased significantly with age. However an obvious increase MOD of PGP.5-positive NFs within the rumen epithelium were observed. In the MP, the nerves and ICs were interwoven to form two complex networks that gradually tightened with age. Furthermore, NSs and nerve trunks were surrounded by a ring-boundary layer consisting of several ICs that became physically closer with aging. Moreover, ICs were located nearby NFs within the ML, forming connections between ICs, smooth muscle cells and axons. This study describes the pattern of neural distribution and its association with ICs in the developing rumen which shed light on the postpartum development of ruminants.
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Affiliation(s)
- Yu Liang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Imran Tarique
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Waseem Ail Vistro
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Yifei Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Ziyu Wang
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Abdul haseeb
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Noor Samad Gandahi
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Adeela Iqbal
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Siyi Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Tianci An
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Huan Yang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Qiusheng Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Ping Yang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
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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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38
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Keef KD, Cobine CA. Control of Motility in the Internal Anal Sphincter. J Neurogastroenterol Motil 2019; 25:189-204. [PMID: 30827084 PMCID: PMC6474703 DOI: 10.5056/jnm18172] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 11/28/2018] [Accepted: 12/09/2018] [Indexed: 12/14/2022] Open
Abstract
The internal anal sphincter (IAS) plays an important role in the maintenance of fecal continence since it generates tone and is responsible for > 70% of resting anal pressure. During normal defecation the IAS relaxes. Historically, tone generation in gastrointestinal muscles was attributed to mechanisms arising directly from smooth muscle cells, ie, myogenic activity. However, slow waves are now known to play a fundamental role in regulating gastrointestinal motility and these electrical events are generated by the interstitial cells of Cajal. Recently, interstitial cells of Cajal, as well as slow waves, have also been identified in the IAS making them viable candidates for tone generation. In this review we discuss four different mechanisms that likely contribute to tone generation in the IAS. Three of these involve membrane potential, L-type Ca2+ channels and electromechanical coupling (ie, summation of asynchronous phasic activity, partial tetanus, and window current), whereas the fourth involves the regulation of myofilament Ca2+ sensitivity. Contractile activity in the IAS is also modulated by sympathetic motor neurons that significantly increase tone and anal pressure, as well as inhibitory motor neurons (particularly nitrergic and vasoactive intestinal peptidergic) that abolish contraction and assist with normal defecation. Alterations in IAS motility are associated with disorders such as fecal incontinence and anal fissures that significantly decrease the quality of life. Understanding in greater detail how tone is regulated in the IAS is important for developing more effective treatment strategies for these debilitating defecation disorders.
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Affiliation(s)
- Kathleen D Keef
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Caroline A Cobine
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
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Blair PJ, Hwang SJ, Shonnard MC, Peri LE, Bayguinov Y, Sanders KM, Ward SM. The Role of Prostaglandins in Disrupted Gastric Motor Activity Associated With Type 2 Diabetes. Diabetes 2019; 68:637-647. [PMID: 30626609 PMCID: PMC6385756 DOI: 10.2337/db18-1064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 11/26/2018] [Indexed: 12/20/2022]
Abstract
Patients with diabetes often develop gastrointestinal motor problems, including gastroparesis. Previous studies have suggested this gastric motor disorder was a consequence of an enteric neuropathy. Disruptions in interstitial cells of Cajal (ICC) have also been reported. A thorough examination of functional changes in gastric motor activity during diabetes has not yet been performed. We comprehensively examined the gastric antrums of Lepob mice using functional, morphological, and molecular techniques to determine the pathophysiological consequences in this type 2 diabetic animal model. Video analysis and isometric force measurements revealed higher frequency and less robust antral contractions in Lepob mice compared with controls. Electrical pacemaker activity was reduced in amplitude and increased in frequency. Populations of enteric neurons, ICC, and platelet-derived growth factor receptor α+ cells were unchanged. Analysis of components of the prostaglandin pathway revealed upregulation of multiple enzymes and receptors. Prostaglandin-endoperoxide synthase-2 inhibition increased slow wave amplitudes and reduced frequency of diabetic antrums. In conclusion, gastric pacemaker and contractile activity is disordered in type 2 diabetic mice, and this appears to be a consequence of excessive prostaglandin signaling. Inhibition of prostaglandin synthesis may provide a novel treatment for diabetic gastric motility disorders.
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Affiliation(s)
- Peter J Blair
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV
| | - Sung Jin Hwang
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV
| | - Matthew C Shonnard
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV
| | - Lauren E Peri
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV
| | - Yulia Bayguinov
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV
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Sergeant GP, Hollywood MA, Thornbury KD. Spontaneous Activity in Urethral Smooth Muscle. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:149-167. [DOI: 10.1007/978-981-13-5895-1_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Sanders KM, Ward SM. Nitric oxide and its role as a non-adrenergic, non-cholinergic inhibitory neurotransmitter in the gastrointestinal tract. Br J Pharmacol 2019; 176:212-227. [PMID: 30063800 PMCID: PMC6295421 DOI: 10.1111/bph.14459] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/06/2018] [Accepted: 07/12/2018] [Indexed: 12/19/2022] Open
Abstract
NO is a neurotransmitter released from enteric inhibitory neurons and responsible for modulating gastrointestinal (GI) motor behaviour. Enteric neurons express nNOS (NOS1) that associates with membranes of nerve varicosities. NO released from neurons binds to soluble guanylate cyclase in post-junctional cells to generate cGMP. cGMP-dependent protein kinase type 1 (PKG1) is a major mediator but perhaps not the only pathway involved in cGMP-mediated effects in GI muscles based on gene deletion studies. NOS1+ neurons form close contacts with smooth muscle cells (SMCs), interstitial cells of Cajal (ICC) and PDGFRα+ cells, and these cells are electrically coupled (SIP syncytium). Cell-specific gene deletion studies have shown that nitrergic responses are due to mechanisms in SMCs and ICC. Controversy exists about the ion channels and other post-junctional mechanisms that mediate nitrergic responses in GI muscles. Reduced nNOS expression in enteric inhibitory motor neurons and/or reduced connectivity between nNOS+ neurons and the SIP syncytium appear to be responsible for motor defects that develop in diabetes. An overproduction of NO in some inflammatory conditions also impairs normal GI motor activity. This review summarizes recent findings regarding the role of NO as an enteric inhibitory neurotransmitter. LINKED ARTICLES: This article is part of a themed section on Nitric Oxide 20 Years from the 1998 Nobel Prize. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.2/issuetoc.
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Affiliation(s)
- Kenton M Sanders
- Department of Physiology and Cell BiologyUniversity of Nevada, Reno, School of MedicineRenoNVUSA
| | - Sean M Ward
- Department of Physiology and Cell BiologyUniversity of Nevada, Reno, School of MedicineRenoNVUSA
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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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Cobine CA, McKechnie M, Brookfield RJ, Hannigan KI, Keef KD. Comparison of inhibitory neuromuscular transmission in the Cynomolgus monkey IAS and rectum: special emphasis on differences in purinergic transmission. J Physiol 2018; 596:5319-5341. [PMID: 30198065 DOI: 10.1113/jp275437] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 09/07/2018] [Indexed: 01/04/2023] Open
Abstract
KEY POINTS Inhibitory neuromuscular transmission (NMT) was compared in the internal anal sphincter (IAS) and rectum of the Cynomolgus monkey, an animal with high gene sequence identity to humans. Nitrergic NMT was present in both muscles while purinergic NMT was limited to the rectum and VIPergic NMT to the IAS. The profile for monkey IAS more closely resembles humans than rodents. In both muscles, SK3 channels were localized to PDGFRα+ cells that were closely associated with nNOS+ /VIP+ nerves. Gene expression levels of P2RY subtypes were the same in IAS and rectum while KCNN expression levels were very similar. SK3 channel activation and inhibition caused faster/greater changes in contractile activity in rectum than IAS. P2Y1 receptor activation inhibited contraction in rectum while increasing contraction in IAS. The absence of purinergic NMT in the IAS may be due to poor coupling between P2Y1 receptors and SK3 channels on PDGFRα+ cells. ABSTRACT Inhibitory neuromuscular transmission (NMT) was compared in the internal anal sphincter (IAS) and rectum of the Cynomolgus monkey, an animal with a high gene sequence identity to humans. Electrical field stimulation produced nitric oxide synthase (NOS)-dependent contractile inhibition in both muscles whereas P2Y1-dependent purinergic NMT was restricted to rectum. An additional NOS-independent, α-chymotrypsin-sensitive component was identified in the IAS consistent with vasoactive intestinal peptide-ergic (VIPergic) NMT. Microelectrode recordings revealed slow NOS-dependent inhibitory junction potentials (IJPs) in both muscles and fast P2Y1-dependent IJPs in rectum. The basis for the difference in purinergic NMT was investigated. PDGFRα+ /SK3+ cells were closely aligned with nNOS+ /VIP+ neurons in both muscles. Gene expression of P2RY was the same in IAS and rectum (P2RY1>>P2RY2-14) while KCNN3 expression was 32% greater in rectum. The SK channel inhibitor apamin doubled contractile activity in rectum while having minimal effect in the IAS. Contractile inhibition elicited with the SK channel agonist CyPPA was five times faster in rectum than in the IAS. The P2Y1 receptor agonist MRS2365 inhibited contraction in rectum but increased contraction in the IAS. In conclusion, both the IAS and the rectum have nitrergic NMT whereas purinergic NMT is limited to rectum and VIPergic NMT to the IAS. The profile in monkey IAS more closely resembles that of humans than rodents. The lack of purinergic NMT in the IAS cannot be attributed to the absence of PDGFRα+ cells, P2Y1 receptors or SK3 channels. Rather, it appears to be due to poor coupling between P2Y1 receptors and SK3 channels on PDGFRα+ cells.
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Affiliation(s)
- C A Cobine
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - M McKechnie
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - R J Brookfield
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - K I Hannigan
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - K D Keef
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA
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Beck K, Friebe A, Voussen B. Nitrergic signaling via interstitial cells of Cajal and smooth muscle cells influences circular smooth muscle contractility in murine colon. Neurogastroenterol Motil 2018; 30:e13300. [PMID: 29377328 DOI: 10.1111/nmo.13300] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 01/03/2018] [Indexed: 12/25/2022]
Abstract
BACKGROUND Regulation of gastrointestinal motility involves excitatory and inhibitory neurotransmission. Nitric oxide (NO), the major inhibitory neurotransmitter, acts via its receptor NO-sensitive guanylyl cyclase (NO-GC). In the GI tract, NO-GC is expressed in several cell types such as smooth muscle cells (SMC) and interstitial cells of Cajal (ICC). Using cell-specific knockout mice, we have previously shown that NO-GC modulates spontaneous contractions in colonic longitudinal smooth muscle. However, its detailed role in the colonic circular smooth muscle is still unclear. METHODS Myography was performed to evaluate spontaneous contractions in rings of proximal colon (2.5 mm) from global (GCKO) and cell-specific knockout mice for NO-GC. Immunohistochemistry and in situ hybridization were used to specify NO-GC expression. KEY RESULTS Colonic circular smooth muscle showed three different contraction patterns: high-frequency ripples, slow phasic contractions, and large contractions. Ripples formed independently of NO-GC. Slow phasic contractions occurred intermittently in WT, SMC-GCKO, and ICC-GCKO tissue, whereas they were more prominent and prolonged in GCKO and SMC/ICC-GCKO tissue. Tetrodotoxin and the NO-GC inhibitor ODQ transformed slow phasic contractions of WT and single cell-specific knockout into GCKO-like contractions. ODQ increased the frequency of large contractions in WT and ICC-GCKO colon but not in GCKO, SMC-GCKO, and SMC/ICC-GCKO preparations. Tetrodotoxin and hexamethonium abolished large contractions. CONCLUSIONS AND INFERENCES We conclude that short rings of murine colon can be effectively used to record spontaneous contractions. Although NO-GC in SMC determines smooth muscle tone, concerted action of NO-GC in both SMC and ICC modulates slow phasic contractions and large contractions.
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Affiliation(s)
- K Beck
- Physiologisches Institut, Universität Würzburg, Würzburg, Germany
| | - A Friebe
- Physiologisches Institut, Universität Würzburg, Würzburg, Germany
| | - B Voussen
- Physiologisches Institut, Universität Würzburg, Würzburg, Germany
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Sung TS, Hwang SJ, Koh SD, Bayguinov Y, Peri LE, Blair PJ, Webb TI, Pardo DM, Rock JR, Sanders KM, Ward SM. The cells and conductance mediating cholinergic neurotransmission in the murine proximal stomach. J Physiol 2018; 596:1549-1574. [PMID: 29430647 PMCID: PMC5924836 DOI: 10.1113/jp275478] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/26/2018] [Indexed: 12/23/2022] Open
Abstract
KEY POINTS Enteric neurotransmission is essential for gastrointestinal (GI) motility, although the cells and conductances responsible for post-junctional responses are controversial. The calcium-activated chloride conductance (CaCC), anoctamin-1 (Ano1), was expressed by intramuscular interstitial cells of Cajal (ICC-IM) in proximal stomach and not resolved in smooth muscle cells (SMCs). Cholinergic nerve fibres were closely apposed to ICC-IM. Conductances activated by cholinergic stimulation in isolated ICC-IM and SMCs were determined. A CaCC was activated by carbachol in ICC-IM and a non-selective cation conductance in SMCs. Responses to cholinergic nerve stimulation were studied. Excitatory junction potentials (EJPs) and mechanical responses were evoked in wild-type mice but absent or greatly reduced with knockout/down of Ano1. Drugs that block Ano1 inhibited the conductance activated by carbachol in ICC-IM and EJPs and mechanical responses in tissues. The data of the present study suggest that electrical and mechanical responses to cholinergic nerve stimulation are mediated by Ano1 expressed in ICC-IM and not SMCs. ABSTRACT Enteric motor neurotransmission is essential for normal gastrointestinal (GI) motility. Controversy exists regarding the cells and ionic conductance(s) that mediate post-junctional neuroeffector responses to motor neurotransmitters. Isolated intramuscular ICC (ICC-IM) and smooth muscle cells (SMCs) from murine fundus muscles were used to determine the conductances activated by carbachol (CCh) in each cell type. The calcium-activated chloride conductance (CaCC), anoctamin-1 (Ano1) is expressed by ICC-IM but not resolved in SMCs, and CCh activated a Cl- conductance in ICC-IM and a non-selective cation conductance in SMCs. We also studied responses to nerve stimulation using electrical-field stimulation (EFS) of intact fundus muscles from wild-type and Ano1 knockout mice. EFS activated excitatory junction potentials (EJPs) in wild-type mice, although EJPs were absent in mice with congenital deactivation of Ano1 and greatly reduced in animals in which the CaCC-Ano1 was knocked down using Cre/loxP technology. Contractions to cholinergic nerve stimulation were also greatly reduced in Ano1 knockouts. SMCs cells also have receptors and ion channels activated by muscarinic agonists. Blocking acetylcholine esterase with neostigmine revealed a slow depolarization that developed after EJPs in wild-type mice. This depolarization was still apparent in mice with genetic deactivation of Ano1. Pharmacological blockers of Ano1 also inhibited EJPs and contractile responses to muscarinic stimulation in fundus muscles. The data of the present study are consistent with the hypothesis that ACh released from motor nerves binds muscarinic receptors on ICC-IM with preference and activates Ano1. If metabolism of acetylcholine is inhibited, ACh overflows and binds to extrajunctional receptors on SMCs, eliciting a slower depolarization response.
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Affiliation(s)
- Tae Sik Sung
- Department of Physiology and Cell Biology, University of NevadaReno School of MedicineRenoNVUSA
| | - Sung Jin Hwang
- Department of Physiology and Cell Biology, University of NevadaReno School of MedicineRenoNVUSA
| | - Sang Don Koh
- Department of Physiology and Cell Biology, University of NevadaReno School of MedicineRenoNVUSA
| | - Yulia Bayguinov
- Department of Physiology and Cell Biology, University of NevadaReno School of MedicineRenoNVUSA
| | - Lauen E. Peri
- Department of Physiology and Cell Biology, University of NevadaReno School of MedicineRenoNVUSA
| | - Peter J. Blair
- Department of Physiology and Cell Biology, University of NevadaReno School of MedicineRenoNVUSA
| | - Timothy I. Webb
- Department of Physiology and Cell Biology, University of NevadaReno School of MedicineRenoNVUSA
| | - David M. Pardo
- Department of AnatomyUniversity of CaliforniaSan FranciscoCAUSA
| | - Jason R. Rock
- Center for Regenerative MedicineBoston University School of MedicineBostonMAUSA
| | - Kenton M. Sanders
- Department of Physiology and Cell Biology, University of NevadaReno School of MedicineRenoNVUSA
| | - Sean M. Ward
- Department of Physiology and Cell Biology, University of NevadaReno School of MedicineRenoNVUSA
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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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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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Gibbons SJ. Not just there to fill space: profound observations on interstitial cells of Cajal in the gastric fundus. J Physiol 2018; 596:1535-1536. [PMID: 29508395 DOI: 10.1113/jp275923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Simon J Gibbons
- Enteric Neuroscience Program, Mayo Clinic, Rochester, MN, 55905, USA
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Halim MA, Degerblad M, Sundbom M, Karlbom U, Holst JJ, Webb DL, Hellström PM. Glucagon-Like Peptide-1 Inhibits Prandial Gastrointestinal Motility Through Myenteric Neuronal Mechanisms in Humans. J Clin Endocrinol Metab 2018; 103:575-585. [PMID: 29177486 DOI: 10.1210/jc.2017-02006] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 11/16/2017] [Indexed: 02/07/2023]
Abstract
CONTEXT Glucagon-like peptide-1 (GLP-1) secretion from l-cells and postprandial inhibition of gastrointestinal motility. OBJECTIVE Investigate whether physiological plasma concentrations of GLP-1 inhibit human postprandial motility and determine mechanism of action of GLP-1 and analog ROSE-010 action. DESIGN Single-blind parallel study. SETTING University hospital laboratory. PARTICIPANTS Healthy volunteers investigated with antroduodenal manometry. Human gastric and intestinal muscle strips. INTERVENTIONS Motility indices (MIs) obtained before and during GLP-1 or saline infusion. Plasma GLP-1 and glucagon-like peptide-2 (GLP-2) measured by radioimmunoassay. Gastrointestinal muscle strips investigated for GLP-1- and ROSE-010-induced relaxation employing GLP-1 and GLP-2 and their receptor localization, and blockers exendin(9-39)amide, Lω-nitro-monomethylarginine (L-NMMA), 2',5'-dideoxyadenosine (DDA), and tetrodotoxin (TTX) to reveal target mechanism of GLP-1 action. MAIN OUTCOME MEASURES Postprandial gastrointestinal relaxation by GLP-1. RESULTS In humans, food intake increased MI to 6.4 ± 0.3 (antrum), 5.7 ± 0.4 (duodenum), and 5.9 ± 0.2 (jejunum). GLP-1 administered intravenously raised plasma GLP-1, but not GLP-2. GLP-1 0.7 pmol/kg/min suppressed corresponding MI to 4.6 ± 0.2, 4.7 ± 0.4, and 5.0 ± 0.2, whereas 1.2 pmol/kg/min suppressed MI to 5.4 ± 0.2, 4.4 ± 0.3, and 5.4 ± 0.3 (P < 0.0001 to 0.005). In vitro, GLP-1 and ROSE-010 prevented contractions by bethanechol and electric field stimulation (P < 0.005 to 0.05). These effects were disinhibited by exendin(9-39)amide, L-NMMA, DDA, or TTX. GLP-1 and GLP-2 were localized to epithelial cells, GLP-1 also at myenteric neurons. GLP-1R and GLP-2R were localized at myenteric neurons but not muscle. CONCLUSIONS GLP-1 and ROSE-010 inhibit postprandial gastrointestinal motility through GLP-1R at myenteric neurons, involving nitrergic and cyclic adenosine monophosphate-dependent mechanisms.
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Affiliation(s)
- Md Abdul Halim
- Department of Medical Sciences, Gastroenterology Unit, Uppsala University, Uppsala, Sweden
| | - Marie Degerblad
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Magnus Sundbom
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Urban Karlbom
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Jens Juul Holst
- NNF Center for Basic Metabolic Research and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dominic-Luc Webb
- Department of Medical Sciences, Gastroenterology Unit, Uppsala University, Uppsala, Sweden
| | - Per M Hellström
- Department of Medical Sciences, Gastroenterology Unit, Uppsala University, Uppsala, Sweden
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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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