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Zholos AV, Melnyk MI, Dryn DO. Molecular mechanisms of cholinergic neurotransmission in visceral smooth muscles with a focus on receptor-operated TRPC4 channel and impairment of gastrointestinal motility by general anaesthetics and anxiolytics. Neuropharmacology 2024; 242:109776. [PMID: 37913983 DOI: 10.1016/j.neuropharm.2023.109776] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/13/2023] [Accepted: 10/23/2023] [Indexed: 11/03/2023]
Abstract
Acetylcholine is the primary excitatory neurotransmitter in visceral smooth muscles, wherein it binds to and activates two muscarinic receptors subtypes, M2 and M3, thus causing smooth muscle excitation and contraction. The first part of this review focuses on the types of cells involved in cholinergic neurotransmission and on the molecular mechanisms underlying acetylcholine-induced membrane depolarisation, which is the central event of excitation-contraction coupling causing Ca2+ entry via L-type Ca2+ channels and smooth muscle contraction. Studies of the muscarinic cation current in intestinal myocytes (mICAT) revealed its main molecular counterpart, receptor-operated TRPC4 channel, which is activated in synergy by both M2 and M3 receptors. M3 receptors activation is of permissive nature, while activation of M2 receptors via Gi/o proteins that are coupled to them plays a direct role in TRPC4 opening. Our understanding of signalling pathways underlying mICAT generation has vastly expanded in recent years through studies of TRPC4 gating in native cells and its regulation in heterologous cells. Recent studies using muscarinic receptor knockout have established that at low agonist concentration activation of both M2 receptor and the M2/M3 receptor complex elicits smooth muscle contraction, while at high agonist concentration M3 receptor function becomes dominant. Based on this knowledge, in the second part of this review we discuss the cellular and molecular mechanisms underlying the numerous anticholinergic effects on neuroactive drugs, in particular general anaesthetics and anxiolytics, which can significantly impair gastrointestinal motility. This article is part of the Special Issue on "Ukrainian Neuroscience".
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Affiliation(s)
- Alexander V Zholos
- Educational and Scientific Centre "Institute of Biology and Medicine", Taras Shevchenko National University of Kyiv, Kyiv, Ukraine.
| | - Mariia I Melnyk
- Educational and Scientific Centre "Institute of Biology and Medicine", Taras Shevchenko National University of Kyiv, Kyiv, Ukraine; A.A. Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Dariia O Dryn
- A.A. Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
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2
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Hellweg CE, Dilruba S, Adrian A, Feles S, Schmitz C, Berger T, Przybyla B, Briganti L, Franz M, Segerer J, Spitta LF, Henschenmacher B, Konda B, Diegeler S, Baumstark-Khan C, Panitz C, Reitz G. Space experiment "Cellular Responses to Radiation in Space (CellRad)": Hardware and biological system tests. LIFE SCIENCES IN SPACE RESEARCH 2015; 7:73-89. [PMID: 26553641 DOI: 10.1016/j.lssr.2015.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/06/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
One factor contributing to the high uncertainty in radiation risk assessment for long-term space missions is the insufficient knowledge about possible interactions of radiation with other spaceflight environmental factors. Such factors, e.g. microgravity, have to be considered as possibly additive or even synergistic factors in cancerogenesis. Regarding the effects of microgravity on signal transduction, it cannot be excluded that microgravity alters the cellular response to cosmic radiation, which comprises a complex network of signaling pathways. The purpose of the experiment "Cellular Responses to Radiation in Space" (CellRad, formerly CERASP) is to study the effects of combined exposure to microgravity, radiation and general space flight conditions on mammalian cells, in particular Human Embryonic Kidney (HEK) cells that are stably transfected with different plasmids allowing monitoring of proliferation and the Nuclear Factor κB (NF-κB) pathway by means of fluorescent proteins. The cells will be seeded on ground in multiwell plate units (MPUs), transported to the ISS, and irradiated by an artificial radiation source after an adaptation period at 0 × g and 1 × g. After different incubation periods, the cells will be fixed by pumping a formaldehyde solution into the MPUs. Ground control samples will be treated in the same way. For implementation of CellRad in the Biolab on the International Space Station (ISS), tests of the hardware and the biological systems were performed. The sequence of different steps in MPU fabrication (cutting, drilling, cleaning, growth surface coating, and sterilization) was optimized in order to reach full biocompatibility. Different coatings of the foil used as growth surface revealed that coating with 0.1 mg/ml poly-D-lysine supports cell attachment better than collagen type I. The tests of prototype hardware (Science Model) proved its full functionality for automated medium change, irradiation and fixation of cells. Exposure of HEK cells to the β-rays emitted by the radiation source dose-dependently decreased cell growth and increased NF-κB activation. The signal of the fluorescent proteins after formaldehyde fixation was stable for at least six months after fixation, allowing storage of the MPUs after fixation for several months before the transport back to Earth and evaluation of the fluorescence intensity. In conclusion, these tests show the feasibility of CellRad on the ISS with the currently available transport mechanisms.
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Affiliation(s)
- Christine E Hellweg
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
| | - Shahana Dilruba
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany
| | - Astrid Adrian
- Airbus Defence and Space GmbH, TSPOE 3 / Payloads - Life Science, 88039 Friedrichshafen, Germany
| | - Sebastian Feles
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany
| | - Claudia Schmitz
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany
| | - Thomas Berger
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany
| | - Bartos Przybyla
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany
| | - Luca Briganti
- Airbus Defence and Space GmbH, TSPOE 3 / Payloads - Life Science, 88039 Friedrichshafen, Germany
| | - Markus Franz
- Airbus Defence and Space GmbH, TSPOE 3 / Payloads - Life Science, 88039 Friedrichshafen, Germany
| | - Jürgen Segerer
- Airbus Defence and Space GmbH, TSPOE 3 / Payloads - Life Science, 88039 Friedrichshafen, Germany
| | - Luis F Spitta
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany
| | - Bernd Henschenmacher
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany
| | - Bikash Konda
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany
| | - Sebastian Diegeler
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany
| | - Christa Baumstark-Khan
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany
| | - Corinna Panitz
- Universitätsklinikum Aachen, Institut für Pharmakologie und Toxikologie, Wendlingweg 2, 52074 Aachen, Germany
| | - Günther Reitz
- Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany
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Chishti AA, Hellweg CE, Berger T, Baumstark-Khan C, Feles S, Kätzel T, Reitz G. Constitutive expression of tdTomato protein as a cytotoxicity and proliferation marker for space radiation biology. LIFE SCIENCES IN SPACE RESEARCH 2015; 4:35-45. [PMID: 26177619 DOI: 10.1016/j.lssr.2014.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 12/21/2014] [Accepted: 12/30/2014] [Indexed: 06/04/2023]
Abstract
The radiation risk assessment for long-term space missions requires knowledge on the biological effectiveness of different space radiation components, e.g. heavy ions, on the interaction of radiation and other space environmental factors such as microgravity, and on the physical and biological dose distribution in the human body. Space experiments and ground-based experiments at heavy ion accelerators require fast and reliable test systems with an easy readout for different endpoints. In order to determine the effect of different radiation qualities on cellular proliferation and the biological depth dose distribution after heavy ion exposure, a stable human cell line expressing a novel fluorescent protein was established and characterized. tdTomato, a red fluorescent protein of the new generation with fast maturation and high fluorescence intensity, was selected as reporter of cell proliferation. Human embryonic kidney (HEK/293) cells were stably transfected with a plasmid encoding tdTomato under the control of the constitutively active cytomegalovirus (CMV) promoter (ptdTomato-N1). The stably transfected cell line was named HEK-ptdTomato-N1 8. This cytotoxicity biosensor was tested by ionizing radiation (X-rays and accelerated heavy ions) exposure. As biological endpoints, the proliferation kinetics and the cell density reached 100 h after irradiation reflected by constitutive expression of the tdTomato were investigated. Both were reduced dose-dependently after radiation exposure. Finally, the cell line was used for biological weighting of heavy ions of different linear energy transfer (LET) as space-relevant radiation quality. The relative biological effectiveness of accelerated heavy ions in reducing cellular proliferation peaked at an LET of 91 keV/μm. The results of this study demonstrate that the HEK-ptdTomato-N1 reporter cell line can be used as a fast and reliable biosensor system for detection of cytotoxic damage caused by ionizing radiation.
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Affiliation(s)
- Arif A Chishti
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Radiation Biology, Linder Höhe, D-51147 Köln, Germany.
| | - Christine E Hellweg
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Radiation Biology, Linder Höhe, D-51147 Köln, Germany.
| | - Thomas Berger
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Radiation Biology, Linder Höhe, D-51147 Köln, Germany.
| | - Christa Baumstark-Khan
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Radiation Biology, Linder Höhe, D-51147 Köln, Germany.
| | - Sebastian Feles
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Radiation Biology, Linder Höhe, D-51147 Köln, Germany.
| | - Thorben Kätzel
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Radiation Biology, Linder Höhe, D-51147 Köln, Germany.
| | - Günther Reitz
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Radiation Biology, Linder Höhe, D-51147 Köln, Germany.
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Abstract
TRPC4 proteins comprise six transmembrane domains, a putative pore-forming region, and an intracellularly located amino- and carboxy-terminus. Among eleven splice variants identified so far, TRPC4α and TRPC4β are the most abundantly expressed and functionally characterized. TRPC4 is expressed in various organs and cell types including the soma and dendrites of numerous types of neurons; the cardiovascular system including endothelial, smooth muscle, and cardiac cells; myometrial and skeletal muscle cells; kidney; and immune cells such as mast cells. Both recombinant and native TRPC4-containing channels differ tremendously in their permeability and other biophysical properties, pharmacological modulation, and mode of activation depending on the cellular environment. They vary from inwardly rectifying store-operated channels with a high Ca(2+) selectivity to non-store-operated channels predominantly carrying Na(+) and activated by Gαq- and/or Gαi-coupled receptors with a complex U-shaped current-voltage relationship. Thus, individual TRPC4-containing channels contribute to agonist-induced Ca(2+) entry directly or indirectly via depolarization and activation of voltage-gated Ca(2+) channels. The differences in channel properties may arise from variations in the composition of the channel complexes, in the specific regulatory pathways in the corresponding cell system, and/or in the expression pattern of interaction partners which comprise other TRPC proteins to form heteromultimeric channels. Additional interaction partners of TRPC4 that can mediate the activity of TRPC4-containing channels include (1) scaffolding proteins (e.g., NHERF) that may mediate interactions with signaling molecules in or in close vicinity to the plasma membrane such as Gα proteins or phospholipase C and with the cytoskeleton, (2) proteins in specific membrane microdomains (e.g., caveolin-1), or (3) proteins on cellular organelles (e.g., Stim1). The diversity of TRPC4-containing channels hampers the development of specific agonists or antagonists, but recently, ML204 was identified as a blocker of both recombinant and endogenous TRPC4-containing channels with an IC50 in the lower micromolar range that lacks activity on most voltage-gated channels and other TRPs except TRPC5 and TRPC3. Lanthanides are specific activators of heterologously expressed TRPC4- and TRPC5-containing channels but can block individual native TRPC4-containing channels. The biological relevance of TRPC4-containing channels was demonstrated by knockdown of TRPC4 expression in numerous native systems including gene expression, cell differentiation and proliferation, formation of myotubes, and axonal regeneration. Studies of TRPC4 single and TRPC compound knockout mice uncovered their role for the regulation of vascular tone, endothelial permeability, gastrointestinal contractility and motility, neurotransmitter release, and social exploratory behavior as well as for excitotoxicity and epileptogenesis. Recently, a single-nucleotide polymorphism (SNP) in the Trpc4 gene was associated with a reduced risk for experience of myocardial infarction.
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Affiliation(s)
- Marc Freichel
- Pharmakologisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany,
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Jeon JP, Hong C, Park EJ, Jeon JH, Cho NH, Kim IG, Choe H, Muallem S, Kim HJ, So I. Selective Gαi subunits as novel direct activators of transient receptor potential canonical (TRPC)4 and TRPC5 channels. J Biol Chem 2012; 287:17029-17039. [PMID: 22457348 DOI: 10.1074/jbc.m111.326553] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ubiquitous transient receptor potential canonical (TRPC) channels function as non-selective, Ca(2+)-permeable channels and mediate numerous cellular functions. It is commonly assumed that TRPC channels are activated by stimulation of Gα(q)-PLC-coupled receptors. However, whether the Gα(q)-PLC pathway is the main regulator of TRPC4/5 channels and how other Gα proteins may regulate these channels are poorly understood. We previously reported that TRPC4/TRPC5 can be activated by Gα(i). In the current work, we found that Gα(i) subunits, rather than Gα(q), are the primary and direct activators of TRPC4 and TRPC5. We report a novel molecular mechanism in which TRPC4 is activated by several Gα(i) subunits, most prominently by Gα(i2), and TRPC5 is activated primarily by Gα(i3). Activation of Gα(i) by the muscarinic M2 receptors or expression of the constitutively active Gα(i) mutants equally and fully activates the channels. Moreover, both TRPC4 and TRPC5 are activated by direct interaction of their conserved C-terminal SESTD (SEC14-like and spectrin-type domains) with the Gα(i) subunits. Two amino acids (lysine 715 and arginine 716) of the TRPC4 C terminus were identified by structural modeling as mediating the interaction with Gα(i2). These findings indicate an essential role of Gα(i) proteins as novel activators for TRPC4/5 and reveal the molecular mechanism by which G-proteins activate the channels.
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Affiliation(s)
- Jae-Pyo Jeon
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Korea
| | - Chansik Hong
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Korea
| | - Eun Jung Park
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Korea
| | - Ju-Hong Jeon
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Korea
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul 110-799, Korea
| | - In-Gyu Kim
- Department of Biochemistry, Seoul National University College of Medicine, Seoul 110-799, Korea
| | - Han Choe
- Department of Physiology, University of Ulsan College of Medicine, Seoul 136-748, Korea
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Hyun Jin Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea.
| | - Insuk So
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Korea.
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Abstract
Ion channels and G-protein-coupled receptors (GPCRs) play a fundamental role in cancer progression by influencing Ca(2+) influx and signaling pathways in transformed cells. Transformed cells thrive in a hostile environment that is characterized by extracellular acidosis that promotes the pathological phenotype. The pathway(s) by which extracellular protons achieve this remain unclear. Here, a role for proton-sensing ion channels and GPCRs as mediators of the effects of extracellular protons in cancer cells is discussed.
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Affiliation(s)
- Maike Glitsch
- Department of Physiology, Anatomy and Genetics, Oxford University, Oxford, United Kingdom.
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Hellweg CE, Baumstark-Khan C, Schmitz C, Lau P, Meier MM, Testard I, Berger T, Reitz G. Carbon-ion-induced activation of the NF-κB pathway. Radiat Res 2011; 175:424-31. [PMID: 21222514 DOI: 10.1667/rr2423.1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Carbon-ion cancer therapy offers several physical and radiobiological advantages over conventional photon cancer therapy. The molecular mechanisms that determine cellular outcome, including the activation of transcription factors and the alteration of gene expression profiles, after carbon-ion exposure are still under investigation. We have previously shown that argon ions (LET 272 keV/µm) had a much higher potential to activate the transcription factor nuclear factor κB (NF-κB) than X rays. NF-κB is involved in the regulation of cellular survival, mostly by antiapoptosis and cell cycle-regulating target genes, which are important in the resistance of cancer cells to radiotherapy. Therefore, activation of the NF-κB pathway by accelerated carbon ions (LET 33 and 73 keV/µm) was examined. For comparison, cells were exposed to 150 kV X rays and to accelerated carbon ions. NF-κB-dependent gene induction after exposure was detected in stably transfected human 293 reporter cells. Carbon ions and X rays had a comparable potential to activate NF-κB in human cells, indicating a comparable usefulness of pharmacological NF-κB inhibition during photon and carbon-ion radiotherapy.
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Affiliation(s)
- Christine E Hellweg
- German Aerospace Centre (DLR), Institute of Aerospace Medicine, Radiation Biology, Linder Höhe, D-51147 Köln, Germany.
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Reboreda A, Jiménez-Díaz L, Navarro-López JD. TRP channels and neural persistent activity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 704:595-613. [PMID: 21290318 DOI: 10.1007/978-94-007-0265-3_32] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
One of the integrative properties of the nervous system is its capability to, by transient motor commands or brief sensory stimuli, evoke persistent neuronal changes, mainly as a sustained, tonic action potential firing. This neural activity, named persistent activity, is found in a good number of brain regions and is thought to be a neural substrate for short-term storage and accumulation of sensory or motor information [1]. Examples of this persistent neural activity have been reported in prefrontal [2] and entorhinal [3] cortices, as part of the neural mechanisms involved in short-term working memory [4]. Interestingly, the general organization of the motor systems assumes the presence of bursts of short-lasting motor commands encoding movement characteristics such as velocity, duration, and amplitude, followed by a maintained tonic firing encoding the position at which the moving appendage should be maintained [5, 6]. Generation of qualitatively similar sustained discharges have also been found in spinal and supraspinal regions in relation to pain processing [7, 8]. Thus, persistent neural activity seems to be necessary for both behavioral (positions of fixation) and cognitive (working memory) processes. Persistent firing mechanisms have been proposed to involve the participation of a non-specific cationic current (CAN current) mainly mediated by activation of TRPC channels. Because the function and generation of persistent activity is still poorly understood, here we aimed to review and discuss the putative role of TRP-like channels on its generation and/or maintenance.
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Affiliation(s)
- Antonio Reboreda
- Section of Physiology, Department of Functional Biology and Health Sciences, School of Biology, University of Vigo, Campus Lagoas-Marcosende 36310 Vigo (Pontevedra), Spain.
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