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Blažič A, Guinard M, Leskovar T, O'Connor RP, Rems L. Long-term changes in transmembrane voltage after electroporation are governed by the interplay between nonselective leak current and ion channel activation. Bioelectrochemistry 2024; 161:108802. [PMID: 39243733 DOI: 10.1016/j.bioelechem.2024.108802] [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: 06/24/2024] [Revised: 08/14/2024] [Accepted: 08/26/2024] [Indexed: 09/09/2024]
Abstract
Electroporation causes a temporal increase in cell membrane permeability and leads to prolonged changes in transmembrane voltage (TMV) in both excitable and non-excitable cells. However, the mechanisms of these TMV changes remain to be fully elucidated. To this end, we monitored TMV over 30 min after exposing two different cell lines to a single 100 µs electroporation pulse using the FLIPR Membrane Potential dye. In CHO-K1 cells, which express very low levels of endogenous ion channels, membrane depolarization following pulse exposure could be explained by nonselective leak current, which persists until the membrane reseals, enabling the cells to recover their resting TMV. In U-87 MG cells, which express many different ion channels, we unexpectedly observed membrane hyperpolarization following the initial depolarization phase, but only at 33 °C and not at 25 °C. We developed a theoretical model, supported by experiments with ion channel inhibitors, which indicated that hyperpolarization could largely be attributed to the activation of calcium-activated potassium channels. Ion channel activation, coupled with changes in TMV and intracellular calcium, participates in various physiological processes, including cell proliferation, differentiation, migration, and apoptosis. Therefore, our study suggests that ion channels could present a potential target for influencing the biological response after electroporation.
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Affiliation(s)
- Anja Blažič
- University of Ljubljana, Faculty of Electrical Engineering, SI-1000 Ljubljana, Slovenia
| | - Manon Guinard
- University of Ljubljana, Faculty of Electrical Engineering, SI-1000 Ljubljana, Slovenia
| | - Tomaž Leskovar
- University of Ljubljana, Faculty of Electrical Engineering, SI-1000 Ljubljana, Slovenia
| | - Rodney P O'Connor
- Mines Saint-Etienne, Centre CMP, Département BEL, F-13541 Gardanne, France
| | - Lea Rems
- University of Ljubljana, Faculty of Electrical Engineering, SI-1000 Ljubljana, Slovenia.
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2
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Wu J, Shindo Y, Hotta K, Vu CQ, Lu K, Wazawa T, Nagai T, Oka K. Calcium-induced upregulation of energy metabolism heats neurons during neural activity. Biochem Biophys Res Commun 2024; 708:149799. [PMID: 38522401 DOI: 10.1016/j.bbrc.2024.149799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 02/13/2024] [Accepted: 03/16/2024] [Indexed: 03/26/2024]
Abstract
Cellular temperature affects every biochemical reaction, underscoring its critical role in cellular functions. In neurons, temperature not only modulates neurotransmission but is also a key determinant of neurodegenerative diseases. Considering that the brain consumes a disproportionately high amount of energy relative to its weight, neural circuits likely generate a lot of heat, which can increase cytosolic temperature. However, the changes in temperature within neurons and the mechanisms of heat generation during neural excitation remain unclear. In this study, we achieved simultaneous imaging of Ca2+ and temperature using the genetically encoded indicators, B-GECO and B-gTEMP. We then compared the spatiotemporal distributions of Ca2+ responses and temperature. Following neural excitation induced by veratridine, an activator of the voltage-gated Na+ channel, we observed an approximately 2 °C increase in cytosolic temperature occurring 30 s after the Ca2+ response. The temperature elevation was observed in the non-nuclear region, while Ca2+ increased throughout the cell body. Moreover, this temperature increase was suppressed under Ca2+-free conditions and by inhibitors of ATP synthesis. These results indicate that Ca2+-induced upregulation of energy metabolism serves as the heat source during neural excitation.
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Affiliation(s)
- Jiayang Wu
- Department of Bioscience and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan
| | - Yutaka Shindo
- Department of Bioscience and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan; School of Frontier Engineering, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Kohji Hotta
- Department of Bioscience and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan
| | - Cong Quang Vu
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan
| | - Kai Lu
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan
| | - Tetsuichi Wazawa
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan
| | - Takeharu Nagai
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan
| | - Kotaro Oka
- Department of Bioscience and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan; School of Frontier Engineering, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan; Waseda Research Institute for Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo, 162-8480, Japan.
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3
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Defaye M, Bradaia A, Abdullah NS, Agosti F, Iftinca M, Delanne-Cuménal M, Soubeyre V, Svendsen K, Gill G, Ozmaeian A, Gheziel N, Martin J, Poulen G, Lonjon N, Vachiery-Lahaye F, Bauchet L, Basso L, Bourinet E, Chiu IM, Altier C. Induction of antiviral interferon-stimulated genes by neuronal STING promotes the resolution of pain in mice. J Clin Invest 2024; 134:e176474. [PMID: 38690737 PMCID: PMC11060736 DOI: 10.1172/jci176474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 03/12/2024] [Indexed: 05/03/2024] Open
Abstract
Inflammation and pain are intertwined responses to injury, infection, or chronic diseases. While acute inflammation is essential in determining pain resolution and opioid analgesia, maladaptive processes occurring during resolution can lead to the transition to chronic pain. Here we found that inflammation activates the cytosolic DNA-sensing protein stimulator of IFN genes (STING) in dorsal root ganglion nociceptors. Neuronal activation of STING promotes signaling through TANK-binding kinase 1 (TBK1) and triggers an IFN-β response that mediates pain resolution. Notably, we found that mice expressing a nociceptor-specific gain-of-function mutation in STING exhibited an IFN gene signature that reduced nociceptor excitability and inflammatory hyperalgesia through a KChIP1-Kv4.3 regulation. Our findings reveal a role of IFN-regulated genes and KChIP1 downstream of STING in the resolution of inflammatory pain.
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Affiliation(s)
- Manon Defaye
- Department of Physiology and Pharmacology, Cumming School of Medicine
- Inflammation Research Network–Snyder Institute for Chronic Diseases, Cumming School of Medicine, and
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Amyaouch Bradaia
- Department of Physiology and Pharmacology, Cumming School of Medicine
- Inflammation Research Network–Snyder Institute for Chronic Diseases, Cumming School of Medicine, and
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Nasser S. Abdullah
- Department of Physiology and Pharmacology, Cumming School of Medicine
- Inflammation Research Network–Snyder Institute for Chronic Diseases, Cumming School of Medicine, and
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Francina Agosti
- Department of Physiology and Pharmacology, Cumming School of Medicine
- Inflammation Research Network–Snyder Institute for Chronic Diseases, Cumming School of Medicine, and
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Mircea Iftinca
- Department of Physiology and Pharmacology, Cumming School of Medicine
- Inflammation Research Network–Snyder Institute for Chronic Diseases, Cumming School of Medicine, and
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Mélissa Delanne-Cuménal
- Department of Physiology and Pharmacology, Cumming School of Medicine
- Inflammation Research Network–Snyder Institute for Chronic Diseases, Cumming School of Medicine, and
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Vanessa Soubeyre
- Department of Neurosurgery, Gui de Chauliac Hospital, Donation and Transplantation Coordination Unit, Montpellier University Medical Center, Montpellier, France
| | - Kristofer Svendsen
- Department of Physiology and Pharmacology, Cumming School of Medicine
- Inflammation Research Network–Snyder Institute for Chronic Diseases, Cumming School of Medicine, and
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Gurveer Gill
- Department of Physiology and Pharmacology, Cumming School of Medicine
- Inflammation Research Network–Snyder Institute for Chronic Diseases, Cumming School of Medicine, and
| | - Aye Ozmaeian
- Department of Physiology and Pharmacology, Cumming School of Medicine
- Inflammation Research Network–Snyder Institute for Chronic Diseases, Cumming School of Medicine, and
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Nadine Gheziel
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), INSERM UMR1291, University of Toulouse III, Toulouse, France
| | - Jérémy Martin
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), INSERM UMR1291, University of Toulouse III, Toulouse, France
| | - Gaetan Poulen
- Department of Neurosurgery, Gui de Chauliac Hospital, Donation and Transplantation Coordination Unit, Montpellier University Medical Center, Montpellier, France
| | - Nicolas Lonjon
- Department of Neurosurgery, Gui de Chauliac Hospital, Donation and Transplantation Coordination Unit, Montpellier University Medical Center, Montpellier, France
| | - Florence Vachiery-Lahaye
- Department of Neurosurgery, Gui de Chauliac Hospital, Donation and Transplantation Coordination Unit, Montpellier University Medical Center, Montpellier, France
| | - Luc Bauchet
- Department of Neurosurgery, Gui de Chauliac Hospital, Donation and Transplantation Coordination Unit, Montpellier University Medical Center, Montpellier, France
- Institute of Functional Genomics, Montpellier University, CNRS, INSERM, Montpellier, France
| | - Lilian Basso
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), INSERM UMR1291, University of Toulouse III, Toulouse, France
| | - Emmanuel Bourinet
- Institute of Functional Genomics, Montpellier University, CNRS, INSERM, Montpellier, France
| | - Isaac M. Chiu
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Christophe Altier
- Department of Physiology and Pharmacology, Cumming School of Medicine
- Inflammation Research Network–Snyder Institute for Chronic Diseases, Cumming School of Medicine, and
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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4
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Cavarretta F, Jaeger D. Modeling Synaptic Integration of Bursty and β Oscillatory Inputs in Ventromedial Motor Thalamic Neurons in Normal and Parkinsonian States. eNeuro 2023; 10:ENEURO.0237-23.2023. [PMID: 37989589 PMCID: PMC10726287 DOI: 10.1523/eneuro.0237-23.2023] [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: 07/06/2023] [Revised: 10/16/2023] [Accepted: 11/05/2023] [Indexed: 11/23/2023] Open
Abstract
The ventromedial motor thalamus (VM) is implicated in multiple motor functions and occupies a central position in the cortico-basal ganglia-thalamocortical loop. It integrates glutamatergic inputs from motor cortex (MC) and motor-related subcortical areas, and it is a major recipient of inhibition from basal ganglia. Previous in vitro experiments performed in mice showed that dopamine depletion enhances the excitability of thalamocortical (TC) neurons in VM due to reduced M-type potassium currents. To understand how these excitability changes impact synaptic integration in vivo, we constructed biophysically detailed mouse VM TC model neurons fit to normal and dopamine-depleted conditions, using the NEURON simulator. These models allowed us to assess the influence of excitability changes with dopamine depletion on the integration of synaptic inputs expected in vivo We found that VM neuron models in the dopamine-depleted state showed increased firing rates with the same synaptic inputs. Synchronous bursting in inhibitory input from the substantia nigra pars reticulata (SNR), as observed in parkinsonian conditions, evoked a postinhibitory firing rate increase with a longer duration in dopamine-depleted than control conditions, due to different M-type potassium channel densities. With β oscillations in the inhibitory inputs from SNR and the excitatory inputs from cortex, we observed spike-phase locking in the activity of the models in normal and dopamine-depleted states, which relayed and amplified the oscillations of the inputs, suggesting that the increased β oscillations observed in VM of parkinsonian animals are predominantly a consequence of changes in the presynaptic activity rather than changes in intrinsic properties.
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Affiliation(s)
| | - Dieter Jaeger
- Department of Biology, Emory University, Atlanta, GA 30322
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5
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Ben-Abu Y, Tucker SJ, Contera S. Transcending Markov: non-Markovian rate processes of thermosensitive TRP ion channels. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230984. [PMID: 37621668 PMCID: PMC10445021 DOI: 10.1098/rsos.230984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 08/02/2023] [Indexed: 08/26/2023]
Abstract
The Markov state model (MSM) is a popular theoretical tool for describing the hierarchy of time scales involved in the function of many proteins especially ion channel gating. An MSM is a particular case of the general non-Markovian model, where the rate of transition from one state to another does not depend on the history of state occupancy within the system, i.e. it only includes reversible, non-dissipative processes. However, an MSM requires knowledge of the precise conformational state of the protein and is not predictive when those details are not known. In the case of ion channels, this simple description fails in real (non-equilibrium) situations, for example when local temperature changes, or when energy losses occur during channel gating. Here, we show it is possible to use non-Markovian equations (i.e. offer a general description that includes the MSM as a particular case) to develop a relatively simple analytical model that describes the non-equilibrium behaviour of the temperature-sensitive transient receptor potential (TRP) ion channels, TRPV1 and TRPM8. This model accurately predicts asymmetrical opening and closing rates, infinite processes and the creation of new states, as well as the effect of temperature changes throughout the process. This approach therefore overcomes the limitations of the MSM and allows us to go beyond a mere phenomenological description of the dynamics of ion channel gating towards a better understanding of the physics underlying these processes.
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Affiliation(s)
- Yuval Ben-Abu
- Physics Unit, Sapir Academic College, Sderot, Hof Ashkelon 79165, Israel
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Stephen J Tucker
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford OX1 3QU, UK
| | - Sonia Contera
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
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6
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Ma Z, Paudel U, Foskett JK. Effects of temperature on action potentials and ion conductances in type II taste-bud cells. Am J Physiol Cell Physiol 2023; 325:C155-C171. [PMID: 37273235 PMCID: PMC10312327 DOI: 10.1152/ajpcell.00413.2022] [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: 09/06/2022] [Revised: 05/30/2023] [Accepted: 05/31/2023] [Indexed: 06/06/2023]
Abstract
Temperature strongly influences the intensity of taste, but it remains understudied despite its physiological, hedonic, and commercial implications. The relative roles of the peripheral gustatory and somatosensory systems innervating the oral cavity in mediating thermal effects on taste sensation and perception are poorly understood. Type II taste-bud cells, responsible for sensing sweet, bitter umami, and appetitive NaCl, release neurotransmitters to gustatory neurons by the generation of action potentials, but the effects of temperature on action potentials and the underlying voltage-gated conductances are unknown. Here, we used patch-clamp electrophysiology to explore the effects of temperature on acutely isolated type II taste-bud cell electrical excitability and whole cell conductances. Our data reveal that temperature strongly affects action potential generation, properties, and frequency and suggest that thermal sensitivities of underlying voltage-gated Na+ and K+ channel conductances provide a mechanism for how and whether voltage-gated Na+ and K+ channels in the peripheral gustatory system contribute to the influence of temperature on taste sensitivity and perception.NEW & NOTEWORTHY The temperature of food affects how it tastes. Nevertheless, the mechanisms involved are not well understood, particularly whether the physiology of taste-bud cells in the mouth is involved. Here we show that the electrical activity of type II taste-bud cells that sense sweet, bitter, and umami substances is strongly influenced by temperature. These results suggest a mechanism for the influence of temperature on the intensity of taste perception that resides in taste buds themselves.
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Affiliation(s)
- Zhongming Ma
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Usha Paudel
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - J Kevin Foskett
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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7
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Boubes K, Batlle D, Tang T, Torres J, Paul V, Abdul HM, Rosa RM. Serum potassium changes during hypothermia and rewarming: a case series and hypothesis on the mechanism. Clin Kidney J 2023; 16:827-834. [PMID: 37151414 PMCID: PMC10157793 DOI: 10.1093/ckj/sfac158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Indexed: 11/14/2022] Open
Abstract
Introduction Hypokalemia is known to occur in association with therapeutically induced hypothermia and is usually managed by the administration of potassium (K+). Methods We reviewed data from 74 patients who underwent a therapeutic hypothermia protocol at our medical institution. Results In four patients in whom data on serum K+ and temperature were available, a strong positive correlation between serum K+ and body temperature was found. Based on the close positive relationship between serum K+ and total body temperature, we hypothesize that serum K+ decreases during hypothermia owing to decreased activity of temperature-dependent K+ exit channels that under normal conditions are sufficiently active to match cellular K+ intake via sodium/K+/adenosine triphosphatase. Upon rewarming, reactivation of these channels results in a rapid increase in serum K+ as a result of K+ exit down its concentration gradient. Conclusion Administration of K+ during hypothermia should be done cautiously and avoided during rewarming to avoid potentially life-threatening hyperkalemia. K+ exit via temperature-dependent K+ channels provides a logical explanation for the rebound hyperkalemia. K+ exit channels may play a bigger role than previously appreciated in the regulation of serum K+ during normal and pathophysiological conditions.
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Affiliation(s)
- Khaled Boubes
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Ohio State University, Columbus, OH, USA
| | - Daniel Batlle
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Tanya Tang
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Foothills Nephrology, Spartanburg, SC, USA
| | - Javier Torres
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Vivek Paul
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | | | - Robert M Rosa
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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8
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Haragopal H, Winters BD. Principal neuron diversity in the murine lateral superior olive supports multiple sound localization strategies and segregation of information in higher processing centers. Commun Biol 2023; 6:432. [PMID: 37076594 PMCID: PMC10115857 DOI: 10.1038/s42003-023-04802-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 04/04/2023] [Indexed: 04/21/2023] Open
Abstract
Principal neurons (PNs) of the lateral superior olive nucleus (LSO) in the brainstem of mammals compare information between the two ears and enable sound localization on the horizontal plane. The classical view of the LSO is that it extracts ongoing interaural level differences (ILDs). Although it has been known for some time that LSO PNs have intrinsic relative timing sensitivity, recent reports further challenge conventional thinking, suggesting the major function of the LSO is detection of interaural time differences (ITDs). LSO PNs include inhibitory (glycinergic) and excitatory (glutamatergic) neurons which differ in their projection patterns to higher processing centers. Despite these distinctions, intrinsic property differences between LSO PN types have not been explored. The intrinsic cellular properties of LSO PNs are fundamental to how they process and encode information, and ILD/ITD extraction places disparate demands on neuronal properties. Here we examine the ex vivo electrophysiology and cell morphology of inhibitory and excitatory LSO PNs in mice. Although overlapping, properties of inhibitory LSO PNs favor time coding functions while those of excitatory LSO PNs favor integrative level coding. Inhibitory and excitatory LSO PNs exhibit different activation thresholds, potentially providing further means to segregate information in higher processing centers. Near activation threshold, which may be physiologically similar to the sensitive transition point in sound source location for LSO, all LSO PNs exhibit single-spike onset responses that can provide optimal time encoding ability. As stimulus intensity increases, LSO PN firing patterns diverge into onset-burst cells, which can continue to encode timing effectively regardless of stimulus duration, and multi-spiking cells, which can provide robust individually integrable level information. This bimodal response pattern may produce a multi-functional LSO which can encode timing with maximum sensitivity and respond effectively to a wide range of sound durations and relative levels.
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Affiliation(s)
- Hariprakash Haragopal
- Department of Anatomy and Neurobiology and Hearing Research Group, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Bradley D Winters
- Department of Anatomy and Neurobiology and Hearing Research Group, Northeast Ohio Medical University, Rootstown, OH, USA.
- Brain Health Research Institute, Kent State University, Kent, OH, USA.
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9
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Faini G, Tanese D, Molinier C, Telliez C, Hamdani M, Blot F, Tourain C, de Sars V, Del Bene F, Forget BC, Ronzitti E, Emiliani V. Ultrafast light targeting for high-throughput precise control of neuronal networks. Nat Commun 2023; 14:1888. [PMID: 37019891 PMCID: PMC10074378 DOI: 10.1038/s41467-023-37416-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 03/16/2023] [Indexed: 04/07/2023] Open
Abstract
Two-photon, single-cell resolution optogenetics based on holographic light-targeting approaches enables the generation of precise spatiotemporal neuronal activity patterns and thus a broad range of experimental applications, such as high throughput connectivity mapping and probing neural codes for perception. Yet, current holographic approaches limit the resolution for tuning the relative spiking time of distinct cells to a few milliseconds, and the achievable number of targets to 100-200, depending on the working depth. To overcome these limitations and expand the capabilities of single-cell optogenetics, we introduce an ultra-fast sequential light targeting (FLiT) optical configuration based on the rapid switching of a temporally focused beam between holograms at kHz rates. We used FLiT to demonstrate two illumination protocols, termed hybrid- and cyclic-illumination, and achieve sub-millisecond control of sequential neuronal activation and high throughput multicell illumination in vitro (mouse organotypic and acute brain slices) and in vivo (zebrafish larvae and mice), while minimizing light-induced thermal rise. These approaches will be important for experiments that require rapid and precise cell stimulation with defined spatio-temporal activity patterns and optical control of large neuronal ensembles.
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Affiliation(s)
- Giulia Faini
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Dimitrii Tanese
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Clément Molinier
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Cécile Telliez
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Massilia Hamdani
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Francois Blot
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Christophe Tourain
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Vincent de Sars
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Filippo Del Bene
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Benoît C Forget
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Emiliano Ronzitti
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France.
| | - Valentina Emiliani
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France.
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10
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Powell DJ, Owens E, Bergsund MM, Cooper M, Newstein P, Berner E, Janmohamed R, Dickinson PS. The role of feedback and modulation in determining temperature resiliency in the lobster cardiac nervous system. Front Neurosci 2023; 17:1113843. [PMID: 36968508 PMCID: PMC10034192 DOI: 10.3389/fnins.2023.1113843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 02/23/2023] [Indexed: 03/12/2023] Open
Abstract
Changes in ambient temperature affect all biological processes. However, these effects are process specific and often vary non-linearly. It is thus a non-trivial problem for neuronal circuits to maintain coordinated, functional output across a range of temperatures. The cardiac nervous systems in two species of decapod crustaceans, Homarus americanus and Cancer borealis, can maintain function across a wide but physiologically relevant temperature range. However, the processes that underlie temperature resilience in neuronal circuits and muscle systems are not fully understood. Here, we demonstrate that the non-isolated cardiac nervous system (i.e., the whole heart: neurons, effector organs, intrinsic feedback systems) in the American lobster, H. americanus, is more sensitive to warm temperatures than the isolated cardiac ganglion (CG) that controls the heartbeat. This was surprising as modulatory processes known to stabilize the output from the CG are absent when the ganglion is isolated. One source of inhibitory feedback in the intact cardiac neuromuscular system is nitric oxide (NO), which is released in response to heart contractions. We hypothesized that the greater temperature tolerance observed in the isolated CG is due to the absence of NO feedback. Here, we demonstrate that applying an NO donor to the isolated CG reduces its temperature tolerance. Similarly, we show that the NO synthase inhibitor L-nitroarginine (LNA) increases the temperature tolerance of the non-isolated nervous system. This is sufficient to explain differences in temperature tolerance between the isolated CG and the whole heart. However, in an intact lobster, the heart and CG are modulated by an array of endogenous peptides and hormones, many of which are positive regulators of the heartbeat. Many studies have demonstrated that excitatory modulators increase temperature resilience. However, this neuromuscular system is regulated by both excitatory and inhibitory peptide modulators. Perfusing SGRNFLRFamide, a FLRFamide-like peptide, through the heart increases the non-isolated nervous system’s tolerance to high temperatures. In contrast, perfusing myosuppressin, a peptide that negatively regulates the heartbeat frequency, decreases the temperature tolerance. Our data suggest that, in this nervous system, positive regulators of neural output increase temperature tolerance of the neuromuscular system, while modulators that decrease neural output decrease temperature tolerance.
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Affiliation(s)
- Daniel J. Powell
- Department of Biology, Bowdoin College, Brunswick, ME, United States
- Program in Neuroscience, Bowdoin College, Brunswick, ME, United States
| | - Elizabeth Owens
- Program in Neuroscience, Bowdoin College, Brunswick, ME, United States
| | - Marie M. Bergsund
- Program in Neuroscience, Bowdoin College, Brunswick, ME, United States
| | - Maren Cooper
- Program in Neuroscience, Bowdoin College, Brunswick, ME, United States
| | - Peter Newstein
- Program in Neuroscience, Bowdoin College, Brunswick, ME, United States
| | - Emily Berner
- Program in Neuroscience, Bowdoin College, Brunswick, ME, United States
| | - Rania Janmohamed
- Program in Neuroscience, Bowdoin College, Brunswick, ME, United States
| | - Patsy S. Dickinson
- Department of Biology, Bowdoin College, Brunswick, ME, United States
- Program in Neuroscience, Bowdoin College, Brunswick, ME, United States
- *Correspondence: Patsy S. Dickinson,
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11
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Del Vecchio G, Galindo-Sánchez CE, Tripp-Valdez MA, López-Landavery EA, Rosas C, Mascaró M. Transcriptomic response in thermally challenged seahorses Hippocampus erectus: The effect of magnitude and rate of temperature change. Comp Biochem Physiol B Biochem Mol Biol 2022; 262:110771. [PMID: 35691555 DOI: 10.1016/j.cbpb.2022.110771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 05/17/2022] [Accepted: 06/06/2022] [Indexed: 10/18/2022]
Abstract
Hippocampus erectus inhabiting the shallow coastal waters of the southern Gulf of Mexico are naturally exposed to marked temperature variations occurring in different temporal scales. Under such heterogeneous conditions, a series of physiological and biochemical adjustments take place to restore and maintain homeostasis. This study investigated the molecular mechanisms involved in the response of H. erectus to increased temperature using transcriptome analysis based on RNA-Seq technology. Data was obtained from seahorses after 0.5-h exposure to combinations of different target temperatures (26 °C: control, and increased to 30 and 33 °C) and rates of thermal increase (abrupt: < 5 min; gradual: 1-1.5 °C every 3 h). The transcriptome of seahorses was assembled de novo using Trinity software to obtain 29,211 genes and 30,479 transcripts comprising 27,520,965 assembled bases. Seahorse exposure to both 30 and 33 °C triggered characteristic processes of the cellular stress response, regardless of the rate of thermal change. The transcriptomic profiles of H. erectus suggest an arrest of muscle development processes, the activation of heat shock proteins, and a switch to anaerobic metabolism within the first 0.5 h of exposure to target temperatures to ensure energy supply. Interestingly, apoptotic processes involving caspase were activated principally in gradual treatments, suggesting that prolonged exposure to even sublethal temperatures results in the accumulation of deleterious effects that may eventually terminate in cellular death. Results herein validate 30 °C and 33 °C as potential upper limits of thermal tolerance for H. erectus at the southernmost boundary of its geographic distribution.
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Affiliation(s)
- G Del Vecchio
- Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - C E Galindo-Sánchez
- Departamento de Biotecnología Marina, Laboratorio de Genómica Funcional, CICESE, Ensenada, Baja California, Mexico. https://twitter.com/ClaraGalindo3
| | - M A Tripp-Valdez
- Departamento de Biotecnología Marina, Laboratorio de Genómica Funcional, CICESE, Ensenada, Baja California, Mexico. https://twitter.com/MiguelTripp
| | - E A López-Landavery
- Departamento de Biotecnología Marina, Laboratorio de Genómica Funcional, CICESE, Ensenada, Baja California, Mexico. https://twitter.com/EdgarLo30205255
| | - C Rosas
- Unidad Multidisciplinaria de Docencia e Investigación-Sisal, Facultad de Ciencias, Universidad Nacional Autónoma de México, Sisal, Yucatán, Mexico. https://twitter.com/DrCarlosRosasV
| | - M Mascaró
- Unidad Multidisciplinaria de Docencia e Investigación-Sisal, Facultad de Ciencias, Universidad Nacional Autónoma de México, Sisal, Yucatán, Mexico.
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12
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Gonzalez KC, Losonczy A, Negrean A. Dendritic Excitability and Synaptic Plasticity In Vitro and In Vivo. Neuroscience 2022; 489:165-175. [PMID: 34998890 PMCID: PMC9392867 DOI: 10.1016/j.neuroscience.2021.12.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 02/06/2023]
Abstract
Much of our understanding of dendritic and synaptic physiology comes from in vitro experimentation, where the afforded mechanical stability and convenience of applying drugs allowed patch-clamping based recording techniques to investigate ion channel distributions, their gating kinetics, and to uncover dendritic integrative and synaptic plasticity rules. However, with current efforts to study these questions in vivo, there is a great need to translate existing knowledge between in vitro and in vivo experimental conditions. In this review, we identify discrepancies between in vitro and in vivo ionic composition of extracellular media and discuss how changes in ionic composition alter dendritic excitability and plasticity induction. Here, we argue that under physiological in vivo ionic conditions, dendrites are expected to be more excitable and the threshold for synaptic plasticity induction to be lowered. Consequently, the plasticity rules described in vitro vary significantly from those implemented in vivo.
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Affiliation(s)
- Kevin C Gonzalez
- Department of Neuroscience, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, New York, NY, USA.
| | - Attila Losonczy
- Department of Neuroscience, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, New York, NY, USA; Kavli Institute for Brain Science, New York, NY, USA.
| | - Adrian Negrean
- Department of Neuroscience, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, New York, NY, USA.
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13
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Luu DD, Owens AM, Mebrat MD, Van Horn WD. A molecular perspective on identifying TRPV1 thermosensitive regions and disentangling polymodal activation. Temperature (Austin) 2021; 10:67-101. [PMID: 37187836 PMCID: PMC10177694 DOI: 10.1080/23328940.2021.1983354] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 09/10/2021] [Accepted: 09/16/2021] [Indexed: 10/20/2022] Open
Abstract
TRPV1 is a polymodal receptor ion channel that is best known to function as a molecular thermometer. It is activated in diverse ways, including by heat, protons (low pH), and vanilloid compounds, such as capsaicin. In this review, we summarize molecular studies of TRPV1 thermosensing, focusing on the cross-talk between heat and other activation modes. Additional insights from TRPV1 isoforms and non-rodent/non-human TRPV1 ortholog studies are also discussed in this context. While the molecular mechanism of heat activation is still emerging, it is clear that TRPV1 thermosensing is modulated allosterically, i.e., at a distance, with contributions from many distinct regions of the channel. Similarly, current studies identify cross-talk between heat and other TRPV1 activation modes, such as protons and capsaicin, and that these modes can generally be selectively disentangled. In aggregate, this suggests that future TRPV1 molecular studies should define allosteric pathways and provide mechanistic insight, thereby enabling mode-selective manipulation of the polymodal receptor. These advances are anticipated to have significant implications in both basic and applied biomedical sciences.
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Affiliation(s)
- Dustin D. Luu
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics,Arizona State University, Tempe, Arizona,USA
| | - Aerial M. Owens
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics,Arizona State University, Tempe, Arizona,USA
| | - Mubark D. Mebrat
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics,Arizona State University, Tempe, Arizona,USA
| | - Wade D. Van Horn
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics,Arizona State University, Tempe, Arizona,USA
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14
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Bohler MW, Chowdhury VS, Cline MA, Gilbert ER. Heat Stress Responses in Birds: A Review of the Neural Components. BIOLOGY 2021; 10:biology10111095. [PMID: 34827087 PMCID: PMC8614992 DOI: 10.3390/biology10111095] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/15/2021] [Accepted: 10/20/2021] [Indexed: 12/26/2022]
Abstract
Heat stress is one of the major environmental conditions causing significant losses in the poultry industry and having negative impacts on the world's food economy. Heat exposure causes several physiological impairments in birds, including oxidative stress, weight loss, immunosuppression, and dysregulated metabolism. Collectively, these lead not only to decreased production in the meat industry, but also decreases in the number of eggs laid by 20%, and overall loss due to mortality during housing and transit. Mitigation techniques have been discussed in depth, and include changes in air flow and dietary composition, improved building insulation, use of air cooling in livestock buildings (fogging systems, evaporation panels), and genetic alterations. Most commonly observed during heat exposure are reduced food intake and an increase in the stress response. However, very little has been explored regarding heat exposure, food intake and stress, and how the neural circuitry responsible for sensing temperatures mediate these responses. That thermoregulation, food intake, and the stress response are primarily mediated by the hypothalamus make it reasonable to assume that it is the central hub at which these systems interact and coordinately regulate downstream changes in metabolism. Thus, this review discusses the neural circuitry in birds associated with thermoregulation, food intake, and stress response at the level of the hypothalamus, with a focus on how these systems might interact in the presence of heat exposure.
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Affiliation(s)
- Mark W. Bohler
- Department of Animal and Poultry Sciences, 2160 Litton-Reaves Hall, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA; (M.W.B.); (M.A.C.)
| | - Vishwajit S. Chowdhury
- Laboratory of Stress Physiology and Metabolism, Faculty of Arts and Science, Kyushu University, Fukuoka 819-0395, Japan;
| | - Mark A. Cline
- Department of Animal and Poultry Sciences, 2160 Litton-Reaves Hall, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA; (M.W.B.); (M.A.C.)
| | - Elizabeth R. Gilbert
- Department of Animal and Poultry Sciences, 2160 Litton-Reaves Hall, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA; (M.W.B.); (M.A.C.)
- Correspondence: ; Tel.: +1-(540)-231-4750
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15
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Ford JB, Ganguly M, Zhuo J, McPheeters MT, Jenkins MW, Chiel HJ, Jansen ED. Optimizing thermal block length during infrared neural inhibition to minimize temperature thresholds. J Neural Eng 2021; 18:10.1088/1741-2552/abf00d. [PMID: 33735846 PMCID: PMC11189657 DOI: 10.1088/1741-2552/abf00d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 03/18/2021] [Indexed: 11/11/2022]
Abstract
Objective. Infrared neural inhibition (INI) is a method of blocking the generation or propagation of neural action potentials through laser heating with wavelengths strongly absorbed by water. Recent work has identified that the distance heated along axons, the block length (BL), modulates the temperature needed for inhibition; however, this relationship has not been characterized. This study explores how BL during INI can be optimized towards minimizing its temperature threshold.Approach. To understand the relationship between BL and the temperature required for INI, excised nerves fromAplysia californicawere laser-heated over different lengths of axon during electrical stimulation of compound action potentials. INI was provided by irradiation (λ= 1470 nm) from a custom probe (n= 6 nerves), and subsequent validation was performed by providing heat block using perfused hot media over nerves (n= 5 nerves).Main Results. Two BL regimes were identified. Short BLs (thermal full width at half maximum (tFWHM) = 0.81-1.13 mm) demonstrated that increasing the tFWHM resulted in lower temperature thresholds for INI (p< 0.0125), while longer BLs (tFWHM = 1.13-3.03 mm) showed no significant change between the temperature threshold and tFWHM (p> 0.0125). Validation of this longer regime was performed using perfused hot media over different lengths of nerves. This secondary heating method similarly showed no significant change (p> 0.025) in the temperature threshold (tFWHM = 1.25-4.42 mm).Significance. This work characterized how the temperature threshold for neural heat block varies with BL and identified an optimal BL around tFWHM = 1.13 mm which minimizes both the maximum temperature applied to tissue and the volume of tissue heated during INI. Understanding how to optimally target lengths of nerve to minimize temperature during INI can help inform the design of devices for longitudinal animal studies and human implementation.
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Affiliation(s)
- Jeremy B Ford
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States of America
- Biophotonics Center, Vanderbilt University, Nashville, TN, United States of America
| | - Mohit Ganguly
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States of America
- Biophotonics Center, Vanderbilt University, Nashville, TN, United States of America
| | - Junqi Zhuo
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - Matthew T McPheeters
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - Michael W Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States of America
| | - Hillel J Chiel
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- Department of Biology, Case Western Reserve University, Cleveland, OH, United States of America
- Department of Neuroscience, Case Western Reserve University, Cleveland, OH, United States of America
| | - E Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States of America
- Biophotonics Center, Vanderbilt University, Nashville, TN, United States of America
- Department of Neurological Surgery, Vanderbilt University, Nashville, TN, United States of America
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16
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Powell D, Haddad SA, Gorur-Shandilya S, Marder E. Coupling between fast and slow oscillator circuits in Cancer borealis is temperature-compensated. eLife 2021; 10:60454. [PMID: 33538245 PMCID: PMC7889077 DOI: 10.7554/elife.60454] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 02/01/2021] [Indexed: 12/21/2022] Open
Abstract
Coupled oscillatory circuits are ubiquitous in nervous systems. Given that most biological processes are temperature-sensitive, it is remarkable that the neuronal circuits of poikilothermic animals can maintain coupling across a wide range of temperatures. Within the stomatogastric ganglion (STG) of the crab, Cancer borealis, the fast pyloric rhythm (~1 Hz) and the slow gastric mill rhythm (~0.1 Hz) are precisely coordinated at ~11°C such that there is an integer number of pyloric cycles per gastric mill cycle (integer coupling). Upon increasing temperature from 7°C to 23°C, both oscillators showed similar temperature-dependent increases in cycle frequency, and integer coupling between the circuits was conserved. Thus, although both rhythms show temperature-dependent changes in rhythm frequency, the processes that couple these circuits maintain their coordination over a wide range of temperatures. Such robustness to temperature changes could be part of a toolbox of processes that enables neural circuits to maintain function despite global perturbations.
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Affiliation(s)
- Daniel Powell
- Biology Department and Volen Center, Brandeis University, Waltham, United States
| | - Sara A Haddad
- Biology Department and Volen Center, Brandeis University, Waltham, United States
| | | | - Eve Marder
- Biology Department and Volen Center, Brandeis University, Waltham, United States
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17
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VDAC Gating Thermodynamics, but Not Gating Kinetics, Are Virtually Temperature Independent. Biophys J 2020; 119:2584-2592. [PMID: 33189678 DOI: 10.1016/j.bpj.2020.10.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/06/2020] [Accepted: 10/16/2020] [Indexed: 12/17/2022] Open
Abstract
The voltage-dependent anion channel (VDAC) is the most abundant protein in the mitochondrial outer membrane and an archetypical β-barrel channel. Here, we study the effects of temperature on VDAC channels reconstituted in planar lipid membranes at the single- and multichannel levels within the 20°C to 40°C range. The temperature dependence of conductance measured on a single channel in 1 M KCl shows an increase characterized by a 10°C temperature coefficient Q10 = 1.22 ± 0.02, which exceeds that of the bathing electrolyte solution conductivity, Q10 = 1.17 ± 0.01. The rates of voltage-induced channel transition between the open and closed states measured on multichannel membranes also show statistically significant increases, with temperatures that are consistent with activation energy barriers of ∼10 ± 3 kcal/mol. At the same time, the gating thermodynamics, as characterized by the gating charge and voltage of equipartitioning, does not display any measurable temperature dependence. The two parameters stay within 3.2 ± 0.2 elementary charges and 30 ± 2 mV, respectively. Thus, whereas the channel kinetics, specifically its conductance and rates of gating response to voltage steps, demonstrates a clear increase with temperature, the conformational voltage-dependent equilibria are virtually insensitive to temperature. These results, which may be a general feature of β-barrel channel gating, suggest either an entropy-driven gating mechanism or a role for enthalpy-entropy compensation.
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18
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Yang F, Xu L, Lee BH, Xiao X, Yarov‐Yarovoy V, Zheng J. An Unorthodox Mechanism Underlying Voltage Sensitivity of TRPV1 Ion Channel. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2000575. [PMID: 33101845 PMCID: PMC7578911 DOI: 10.1002/advs.202000575] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 08/05/2020] [Indexed: 05/10/2023]
Abstract
While the capsaicin receptor transient receptor potential vanilloid 1 (TRPV1) channel is a polymodal nociceptor for heat, capsaicin, and protons, the channel's responses to each of these stimuli are profoundly regulated by membrane potential, damping or even prohibiting its response at negative voltages and amplifying its response at positive voltages. Therefore, voltage sensitivity of TRPV1 is anticipated to play an important role in shaping pain responses. How voltage regulates TRPV1 activation remains unknown. Here, it is shown that voltage sensitivity does not originate from the S4 segment like classic voltage-gated ion channels; instead, outer pore acidic residues directly partake in voltage-sensitive activation, with their negative charges collectively constituting the observed gating charges. Outer pore gating-charge movement is titratable by extracellular pH and is allosterically coupled to channel activation, likely by influencing the upper gate in the ion selectivity filter. Elucidating this unorthodox voltage-gating process provides a mechanistic foundation for understanding TRPV1 polymodal gating and opens the door to novel approaches regulating channel activity for pain management.
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Affiliation(s)
- Fan Yang
- Department of Biophysics, and Kidney Disease Center of the First Affiliated HospitalZhejiang University School of Medicine866 Yuhangtang RoadHangzhouZhejiang310058China
- Department of Physiology and Membrane BiologyUniversity of California, DavisOne Shields AvenueDavisCA95616USA
| | - Lizhen Xu
- Department of Biophysics, and Kidney Disease Center of the First Affiliated HospitalZhejiang University School of Medicine866 Yuhangtang RoadHangzhouZhejiang310058China
| | - Bo Hyun Lee
- Department of Physiology and Membrane BiologyUniversity of California, DavisOne Shields AvenueDavisCA95616USA
| | - Xian Xiao
- Department of Physiology and Membrane BiologyUniversity of California, DavisOne Shields AvenueDavisCA95616USA
- School of Life Sciences, Westlake Institute for Advanced StudyWestlake UniversityShilongshan Road No. 18, Xihu DistrictHangzhouZhejiang310064China
| | - Vladimir Yarov‐Yarovoy
- Department of Physiology and Membrane BiologyUniversity of California, DavisOne Shields AvenueDavisCA95616USA
| | - Jie Zheng
- Department of Physiology and Membrane BiologyUniversity of California, DavisOne Shields AvenueDavisCA95616USA
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19
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Kim M, Sisco NJ, Hilton JK, Montano CM, Castro MA, Cherry BR, Levitus M, Van Horn WD. Evidence that the TRPV1 S1-S4 membrane domain contributes to thermosensing. Nat Commun 2020; 11:4169. [PMID: 32820172 PMCID: PMC7441067 DOI: 10.1038/s41467-020-18026-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 07/30/2020] [Indexed: 01/14/2023] Open
Abstract
Sensing and responding to temperature is crucial in biology. The TRPV1 ion channel is a well-studied heat-sensing receptor that is also activated by vanilloid compounds, including capsaicin. Despite significant interest, the molecular underpinnings of thermosensing have remained elusive. The TRPV1 S1-S4 membrane domain couples chemical ligand binding to the pore domain during channel gating. Here we show that the S1-S4 domain also significantly contributes to thermosensing and couples to heat-activated gating. Evaluation of the isolated human TRPV1 S1-S4 domain by solution NMR, far-UV CD, and intrinsic fluorescence shows that this domain undergoes a non-denaturing temperature-dependent transition with a high thermosensitivity. Further NMR characterization of the temperature-dependent conformational changes suggests the contribution of the S1-S4 domain to thermosensing shares features with known coupling mechanisms between this domain with ligand and pH activation. Taken together, this study shows that the TRPV1 S1-S4 domain contributes to TRPV1 temperature-dependent activation.
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Affiliation(s)
- Minjoo Kim
- School of Molecular Sciences, Arizona State University, 551 E. University Drive, Tempe, AZ, 85287, USA
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics, Arizona State University, Tempe, AZ, 85287, USA
| | - Nicholas J Sisco
- School of Molecular Sciences, Arizona State University, 551 E. University Drive, Tempe, AZ, 85287, USA
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics, Arizona State University, Tempe, AZ, 85287, USA
| | - Jacob K Hilton
- School of Molecular Sciences, Arizona State University, 551 E. University Drive, Tempe, AZ, 85287, USA
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics, Arizona State University, Tempe, AZ, 85287, USA
| | - Camila M Montano
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics, Arizona State University, Tempe, AZ, 85287, USA
| | - Manuel A Castro
- School of Molecular Sciences, Arizona State University, 551 E. University Drive, Tempe, AZ, 85287, USA
| | - Brian R Cherry
- The Magnetic Resonance Research Center, Arizona State University, Tempe, AZ, 85287, USA
| | - Marcia Levitus
- School of Molecular Sciences, Arizona State University, 551 E. University Drive, Tempe, AZ, 85287, USA
- The Biodesign Institute Center for Single Molecule Biophysics, Arizona State University, Tempe, AZ, 85287, USA
| | - Wade D Van Horn
- School of Molecular Sciences, Arizona State University, 551 E. University Drive, Tempe, AZ, 85287, USA.
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics, Arizona State University, Tempe, AZ, 85287, USA.
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20
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DeMaegd ML, Stein W. Temperature-robust activity patterns arise from coordinated axonal Sodium channel properties. PLoS Comput Biol 2020; 16:e1008057. [PMID: 32716930 PMCID: PMC7410338 DOI: 10.1371/journal.pcbi.1008057] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 08/06/2020] [Accepted: 06/15/2020] [Indexed: 01/08/2023] Open
Abstract
Action potentials are a key component of neuronal communication and their precise timing is critical for processes like learning, memory, and complex behaviors. Action potentials propagate through long axons to their postsynaptic partners, which requires axons not only to faithfully transfer action potentials to distant synaptic regions but also to maintain their timing. This is particularly challenging when axons differ in their morphological and physiological properties, as timing is predicted to diverge between these axons when extrinsic conditions change. It is unknown if and how diverse axons maintain timing during temperature changes that animals and humans encounter. We studied whether ambient temperature changes cause different timing in the periphery of neurons that centrally produce temperature-robust activity. In an approach combining modeling, imaging, and electrophysiology, we explored mechanisms that support timing by exposing the axons of three different neuron types from the same crustacean (Cancer borealis) motor circuit and involved in the same functional task to a range of physiological temperatures. We show that despite substantial differences between axons, the effects of temperature on action potential propagation were moderate and supported temperature-robust timing over long-distances. Our modeling demonstrates that to maintain timing, the underlying channel properties of these axons do not need to be temperature-insensitive or highly restricted, but coordinating the temperature sensitivities of the Sodium activation gate time constant and the maximum Sodium conductance is required. Thus, even highly temperature-sensitive ion channel properties can support temperature-robust timing between distinct neuronal types and across long distances.
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Affiliation(s)
- Margaret L. DeMaegd
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Wolfgang Stein
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
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21
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Du G, Tian Y, Yao Z, Vu S, Zheng J, Chai L, Wang K, Yang S. A specialized pore turret in the mammalian cation channel TRPV1 is responsible for distinct and species-specific heat activation thresholds. J Biol Chem 2020; 295:9641-9649. [PMID: 32461255 DOI: 10.1074/jbc.ra120.013037] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/20/2020] [Indexed: 11/06/2022] Open
Abstract
The transient receptor potential vanilloid 1 (TRPV1) channel is a heat-activated cation channel that plays a crucial role in ambient temperature detection and thermal homeostasis. Although several structural features of TRPV1 have been shown to be involved in heat-induced activation of the gating process, the physiological significance of only a few of these key elements has been evaluated in an evolutionary context. Here, using transient expression in HEK293 cells, electrophysiological recordings, and molecular modeling, we show that the pore turret contains both structural and functional determinants that set the heat activation thresholds of distinct TRPV1 orthologs in mammals whose body temperatures fluctuate widely. We found that TRPV1 from the bat Carollia brevicauda exhibits a lower threshold temperature of channel activation than does its human ortholog and three bat-specific amino acid substitutions located in the pore turret are sufficient to determine this threshold temperature. Furthermore, the structure of the TRPV1 pore turret appears to be of physiological and evolutionary significance for differentiating the heat-activated threshold among species-specific TRPV1 orthologs. These findings support a role for the TRPV1 pore turret in tuning the heat-activated threshold, and they suggest that its evolution was driven by adaption to specific physiological traits among mammals exposed to variable temperatures.
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Affiliation(s)
- Guangxu Du
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, Shandong, China
| | - Yuhua Tian
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, Shandong, China
| | - Zhihao Yao
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, Shandong, China.,Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of the Yunnan Province Kunming Institute of Zoology, Kunming, Yunnan China
| | - Simon Vu
- University of California Davis, School of Medicine, Davis, California, USA
| | - Jie Zheng
- University of California Davis, School of Medicine, Davis, California, USA
| | - Longhui Chai
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - KeWei Wang
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, Shandong, China
| | - Shilong Yang
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
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22
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Jakšić AM, Karner J, Nolte V, Hsu SK, Barghi N, Mallard F, Otte KA, Svečnjak L, Senti KA, Schlötterer C. Neuronal Function and Dopamine Signaling Evolve at High Temperature in Drosophila. Mol Biol Evol 2020; 37:2630-2640. [DOI: 10.1093/molbev/msaa116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Abstract
Neuronal activity is temperature sensitive and affects behavioral traits important for individual fitness, such as locomotion and courtship. Yet, we do not know enough about the evolutionary response of neuronal phenotypes in new temperature environments. Here, we use long-term experimental evolution of Drosophila simulans populations exposed to novel temperature regimes. Here, we demonstrate a direct relationship between thermal selective pressure and the evolution of neuronally expressed molecular and behavioral phenotypes. Several essential neuronal genes evolve lower expression at high temperatures and higher expression at low temperatures, with dopaminergic neurons standing out by displaying the most consistent expression change across independent replicates. We functionally validate the link between evolved gene expression and behavioral changes by pharmacological intervention in the experimentally evolved D. simulans populations as well as by genetically triggered expression changes of key genes in D. melanogaster. As natural temperature clines confirm our results for Drosophila and Anopheles populations, we conclude that neuronal dopamine evolution is a key factor for temperature adaptation.
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Affiliation(s)
- Ana Marija Jakšić
- Department of Molecular Biology and Genetics, Cornell University, NY
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria
| | - Julia Karner
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
| | - Viola Nolte
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
| | - Sheng-Kai Hsu
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria
| | - Neda Barghi
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
| | - François Mallard
- Institut de Biologie de l’École Normale Supérieure, Paris, France
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
| | | | - Lidija Svečnjak
- Department of Fisheries, Apiculture, Wildlife Management and Special Zoology, Faculty of Agriculture, University of Zagreb, Zagreb, Croatia
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23
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Van Hook MJ. Temperature effects on synaptic transmission and neuronal function in the visual thalamus. PLoS One 2020; 15:e0232451. [PMID: 32353050 PMCID: PMC7192487 DOI: 10.1371/journal.pone.0232451] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 04/15/2020] [Indexed: 12/11/2022] Open
Abstract
Numerous neuronal properties including the synaptic vesicle release process, neurotransmitter receptor complement, and postsynaptic ion channels are involved in transforming synaptic inputs into postsynaptic spiking. Temperature is a significant influencer of neuronal function and synaptic integration. Changing temperature can affect neuronal physiology in a diversity of ways depending on how it affects different members of the cell’s ion channel complement. Temperature’s effects on neuronal function are critical for pathological states such as fever, which can trigger seizure activity, but are also important in interpreting and comparing results of experiments conducted at room vs physiological temperature. The goal of this study was to examine the influence of temperature on synaptic properties and ion channel function in thalamocortical (TC) relay neurons in acute brain slices of the dorsal lateral geniculate nucleus, a key synaptic target of retinal ganglion cells in the thalamus. Warming the superfusate in patch clamp experiments with acutely-prepared brain slices led to an overall inhibition of synaptically-driven spiking behavior in TC neurons in response to a retinal ganglion cell spike train. Further study revealed that this was associated with an increase in presynaptic synaptic vesicle release probability and synaptic depression and altered passive and active membrane properties. Additionally, warming the superfusate triggered activation of an inwardly rectifying potassium current and altered the voltage-dependence of voltage-gated Na+ currents and T-type calcium currents. This study highlights the importance of careful temperature control in ex vivo physiological experiments and illustrates how numerous properties such as synaptic inputs, active conductances, and passive membrane properties converge to determine spike output.
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Affiliation(s)
- Matthew J. Van Hook
- Department of Ophthalmology & Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America
- * E-mail: ,
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24
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Kim JH, Ki Y, Lee H, Hur MS, Baik B, Hur JH, Nam D, Lim C. The voltage-gated potassium channel Shaker promotes sleep via thermosensitive GABA transmission. Commun Biol 2020; 3:174. [PMID: 32296133 PMCID: PMC7160125 DOI: 10.1038/s42003-020-0902-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 03/20/2020] [Indexed: 02/07/2023] Open
Abstract
Genes and neural circuits coordinately regulate animal sleep. However, it remains elusive how these endogenous factors shape sleep upon environmental changes. Here, we demonstrate that Shaker (Sh)-expressing GABAergic neurons projecting onto dorsal fan-shaped body (dFSB) regulate temperature-adaptive sleep behaviors in Drosophila. Loss of Sh function suppressed sleep at low temperature whereas light and high temperature cooperatively gated Sh effects on sleep. Sh depletion in GABAergic neurons partially phenocopied Sh mutants. Furthermore, the ionotropic GABA receptor, Resistant to dieldrin (Rdl), in dFSB neurons acted downstream of Sh and antagonized its sleep-promoting effects. In fact, Rdl inhibited the intracellular cAMP signaling of constitutively active dopaminergic synapses onto dFSB at low temperature. High temperature silenced GABAergic synapses onto dFSB, thereby potentiating the wake-promoting dopamine transmission. We propose that temperature-dependent switching between these two synaptic transmission modalities may adaptively tune the neural property of dFSB neurons to temperature shifts and reorganize sleep architecture for animal fitness. Ji-hyung Kim and Yoonhee Ki et al. show that low temperatures suppress sleep in Drosophila by increasing GABA transmission in Shaker-expressing GABAergic neurons projecting onto the dorsal fan-shaped body, while high temperatures potentiate dopamine-induced arousal by reducing GABA transmission. This study highlights a role for Shaker in sleep modulation via a temperature-dependent switch in GABA signaling.
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Affiliation(s)
- Ji-Hyung Kim
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Yoonhee Ki
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Hoyeon Lee
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Moon Seong Hur
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Bukyung Baik
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jin-Hoe Hur
- UNIST Optical Biomed Imaging Center, UNIST, Ulsan, 44919, Republic of Korea
| | - Dougu Nam
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Chunghun Lim
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
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25
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Milton AO, Wang T, Li W, Guo J, Zhang S. Mechanical stretch increases Kv1.5 current through an interaction between the S1-S2 linker and N-terminus of the channel. J Biol Chem 2020; 295:4723-4732. [PMID: 32122972 DOI: 10.1074/jbc.ra119.011302] [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: 09/30/2019] [Revised: 02/27/2020] [Indexed: 11/06/2022] Open
Abstract
The voltage-gated potassium channel Kv1.5 plays important roles in atrial repolarization and regulation of vascular tone. In the present study, we investigated the effects of mechanical stretch on Kv1.5 channels. We induced mechanical stretch by centrifuging or culturing Kv1.5-expressing HEK 293 cells and neonatal rat ventricular myocytes in low osmolarity (LO) medium and then recorded Kv1.5 current (IKv1.5) in a normal, isotonic solution. We observed that mechanical stretch increased IKv1.5, and this increase required the intact, long, proline-rich extracellular S1-S2 linker of the Kv1.5 channel. The low osmolarity-induced IKv1.5 increase also required an intact intracellular N terminus, which contains the binding motif for endogenous Src tyrosine kinase that constitutively inhibits IKv1.5 Disrupting the Src-binding motif of Kv1.5 through N-terminal truncation or mutagenesis abolished the mechanical stretch-mediated increase in IKv1.5 Our results further showed that the extracellular S1-S2 linker of Kv1.5 communicates with the intracellular N terminus. Although the S1-S2 linker of WT Kv1.5 could be cleaved by extracellularly applied proteinase K (PK), an N-terminal truncation up to amino acid residue 209 altered the conformation of the S1-S2 linker and made it no longer susceptible to proteinase K-mediated cleavage. In summary, the findings of our study indicate that the S1-S2 linker of Kv1.5 represents a mechanosensor that regulates the activity of this channel. By targeting the S1-S2 linker, mechanical stretch may induce a change in the N-terminal conformation of Kv1.5 that relieves Src-mediated tonic channel inhibition and results in an increase in IKv1.5.
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Affiliation(s)
- Alexandria O Milton
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Tingzhong Wang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Wentao Li
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Jun Guo
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Shetuan Zhang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
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26
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Perez-Flores MC, Lee JH, Park S, Zhang XD, Sihn CR, Ledford HA, Wang W, Kim HJ, Timofeyev V, Yarov-Yarovoy V, Chiamvimonvat N, Rabbitt RD, Yamoah EN. Cooperativity of K v7.4 channels confers ultrafast electromechanical sensitivity and emergent properties in cochlear outer hair cells. SCIENCE ADVANCES 2020; 6:eaba1104. [PMID: 32285007 PMCID: PMC7141818 DOI: 10.1126/sciadv.aba1104] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 01/14/2020] [Indexed: 05/22/2023]
Abstract
The mammalian cochlea relies on active electromotility of outer hair cells (OHCs) to resolve sound frequencies. OHCs use ionic channels and somatic electromotility to achieve the process. It is unclear, though, how the kinetics of voltage-gated ionic channels operate to overcome extrinsic viscous drag on OHCs at high frequency. Here, we report ultrafast electromechanical gating of clustered Kv7.4 in OHCs. Increases in kinetics and sensitivity resulting from cooperativity among clustered-Kv7.4 were revealed, using optogenetics strategies. Upon clustering, the half-activation voltage shifted negative, and the speed of activation increased relative to solitary channels. Clustering also rendered Kv7.4 channels mechanically sensitive, confirmed in consolidated Kv7.4 channels at the base of OHCs. Kv7.4 clusters provide OHCs with ultrafast electromechanical channel gating, varying in magnitude and speed along the cochlea axis. Ultrafast Kv7.4 gating provides OHCs with a feedback mechanism that enables the cochlea to overcome viscous drag and resolve sounds at auditory frequencies.
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Affiliation(s)
- Maria C. Perez-Flores
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Jeong H. Lee
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Seojin Park
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Xiao-Dong Zhang
- Department of Internal Medicine, Division of Cardiology, University of California, Davis, Davis, CA 95616, USA
- Department of Veterans Affairs, Northern California Health Care System, Mather, CA 95655, USA
| | - Choong-Ryoul Sihn
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Hannah A. Ledford
- Department of Internal Medicine, Division of Cardiology, University of California, Davis, Davis, CA 95616, USA
| | - Wenying Wang
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Hyo Jeong Kim
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
| | - Valeriy Timofeyev
- Department of Internal Medicine, Division of Cardiology, University of California, Davis, Davis, CA 95616, USA
- Department of Veterans Affairs, Northern California Health Care System, Mather, CA 95655, USA
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA
| | - Nipavan Chiamvimonvat
- Department of Internal Medicine, Division of Cardiology, University of California, Davis, Davis, CA 95616, USA
- Department of Veterans Affairs, Northern California Health Care System, Mather, CA 95655, USA
| | - Richard D. Rabbitt
- Departments of Biomedical Engineering, Otolaryngology, and Neuroscience Program, University of Utah, Salt Lake City, UT 84112, USA
- Corresponding author. (E.N.Y.); (R.D.R.)
| | - Ebenezer N. Yamoah
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, USA
- Corresponding author. (E.N.Y.); (R.D.R.)
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27
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Photosensitive inhibition of the GABA system in vitro. Sci Rep 2020; 10:3133. [PMID: 32081949 PMCID: PMC7035376 DOI: 10.1038/s41598-020-59915-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 01/27/2020] [Indexed: 11/19/2022] Open
Abstract
In the central nervous system (CNS), γ–aminobutyric acid A (GABAA) receptors mediate two types of inhibitory effects. Phasic inhibition involves the activation of synaptic GABAA receptors, and tonic inhibition is mediated by extrasynaptic GABAA receptors. GABAA receptors are important regulators of neuronal activity and are involved in a range of neurological disorders. In this study, we conducted sIPSCs recordings on hippocampal CA1 pyramidal neurons in WT SD rats and found that exposure to blue light could specifically block the tonic inhibition and sIPSCs, and regulate neuronal activity. These observations indicate the existence of a non-opsin photosensitive pathway that regulates the GABA inhibitory system in the CNS.
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28
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Ryu J, Vincent PFY, Ziogas NK, Xu L, Sadeghpour S, Curtin J, Alexandris AS, Stewart N, Sima R, du Lac S, Glowatzki E, Koliatsos VE. Optogenetically transduced human ES cell-derived neural progenitors and their neuronal progenies: Phenotypic characterization and responses to optical stimulation. PLoS One 2019; 14:e0224846. [PMID: 31710637 PMCID: PMC6844486 DOI: 10.1371/journal.pone.0224846] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 10/22/2019] [Indexed: 02/04/2023] Open
Abstract
Optogenetically engineered human neural progenitors (hNPs) are viewed as promising tools in regenerative neuroscience because they allow the testing of the ability of hNPs to integrate within nervous system of an appropriate host not only structurally, but also functionally based on the responses of their differentiated progenies to light. Here, we transduced H9 embryonic stem cell-derived hNPs with a lentivirus harboring human channelrhodopsin (hChR2) and differentiated them into a forebrain lineage. We extensively characterized the fate and optogenetic functionality of hChR2-hNPs in vitro with electrophysiology and immunocytochemistry. We also explored whether the in vivo phenotype of ChR2-hNPs conforms to in vitro observations by grafting them into the frontal neocortex of rodents and analyzing their survival and neuronal differentiation. Human ChR2-hNPs acquired neuronal phenotypes (TUJ1, MAP2, SMI-312, and synapsin 1 immunoreactivity) in vitro after an average of 70 days of coculturing with CD1 astrocytes and progressively displayed both inhibitory and excitatory neurotransmitter signatures by immunocytochemistry and whole-cell patch clamp recording. Three months after transplantation into motor cortex of naïve or injured mice, 60–70% of hChR2-hNPs at the transplantation site expressed TUJ1 and had neuronal cytologies, whereas 60% of cells also expressed ChR2. Transplant-derived neurons extended axons through major commissural and descending tracts and issued synaptophysin+ terminals in the claustrum, endopiriform area, and corresponding insular and piriform cortices. There was no apparent difference in engraftment, differentiation, or connectivity patterns between injured and sham subjects. Same trends were observed in a second rodent host, i.e. rat, where we employed longer survival times and found that the majority of grafted hChR2-hNPs differentiated into GABAergic neurons that established dense terminal fields and innervated mostly dendritic profiles in host cortical neurons. In physiological experiments, human ChR2+ neurons in culture generated spontaneous action potentials (APs) 100–170 days into differentiation and their firing activity was consistently driven by optical stimulation. Stimulation generated glutamatergic and GABAergic postsynaptic activity in neighboring ChR2- cells, evidence that hChR2-hNP-derived neurons had established functional synaptic connections with other neurons in culture. Light stimulation of hChR2-hNP transplants in vivo generated complicated results, in part because of the variable response of the transplants themselves. Our findings show that we can successfully derive hNPs with optogenetic properties that are fully transferrable to their differentiated neuronal progenies. We also show that these progenies have substantial neurotransmitter plasticity in vitro, whereas in vivo they mostly differentiate into inhibitory GABAergic neurons. Furthermore, neurons derived from hNPs have the capacity of establishing functional synapses with postsynaptic neurons in vitro, but this outcome is technically challenging to explore in vivo. We propose that optogenetically endowed hNPs hold great promise as tools to explore de novo circuit formation in the brain and, in the future, perhaps launch a new generation of neuromodulatory therapies.
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Affiliation(s)
- Jiwon Ryu
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Philippe F. Y. Vincent
- Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Nikolaos K. Ziogas
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Leyan Xu
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Shirin Sadeghpour
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - John Curtin
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Athanasios S. Alexandris
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Nicholas Stewart
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Richard Sima
- Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sascha du Lac
- Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Elisabeth Glowatzki
- Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Vassilis E. Koliatsos
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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29
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Lei CL, Clerx M, Beattie KA, Melgari D, Hancox JC, Gavaghan DJ, Polonchuk L, Wang K, Mirams GR. Rapid Characterization of hERG Channel Kinetics II: Temperature Dependence. Biophys J 2019; 117:2455-2470. [PMID: 31451180 PMCID: PMC6990152 DOI: 10.1016/j.bpj.2019.07.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/20/2019] [Accepted: 07/17/2019] [Indexed: 11/29/2022] Open
Abstract
Ion channel behavior can depend strongly on temperature, with faster kinetics at physiological temperatures leading to considerable changes in currents relative to room temperature. These temperature-dependent changes in voltage-dependent ion channel kinetics (rates of opening, closing, inactivating, and recovery) are commonly represented with Q10 coefficients or an Eyring relationship. In this article, we assess the validity of these representations by characterizing channel kinetics at multiple temperatures. We focus on the human Ether-à-go-go-Related Gene (hERG) channel, which is important in drug safety assessment and commonly screened at room temperature so that results require extrapolation to physiological temperature. In Part I of this study, we established a reliable method for high-throughput characterization of hERG1a (Kv11.1) kinetics, using a 15-second information-rich optimized protocol. In this Part II, we use this protocol to study the temperature dependence of hERG kinetics using Chinese hamster ovary cells overexpressing hERG1a on the Nanion SyncroPatch 384PE, a 384-well automated patch-clamp platform, with temperature control. We characterize the temperature dependence of hERG gating by fitting the parameters of a mathematical model of hERG kinetics to data obtained at five distinct temperatures between 25 and 37°C and validate the models using different protocols. Our models reveal that activation is far more temperature sensitive than inactivation, and we observe that the temperature dependency of the kinetic parameters is not represented well by Q10 coefficients; it broadly follows a generalized, but not the standardly-used, Eyring relationship. We also demonstrate that experimental estimations of Q10 coefficients are protocol dependent. Our results show that a direct fit using our 15-s protocol best represents hERG kinetics at any given temperature and suggests that using the Generalized Eyring theory is preferable if no experimental data are available to derive model parameters at a given temperature.
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Affiliation(s)
- Chon Lok Lei
- Computational Biology, Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Michael Clerx
- Computational Biology, Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Kylie A Beattie
- Computational Biology, Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Dario Melgari
- School of Physiology, Pharmacology and Neuroscience, and Cardiovascular Research Laboratories, School of Medical Sciences, University of Bristol, Bristol, United Kingdom
| | - Jules C Hancox
- School of Physiology, Pharmacology and Neuroscience, and Cardiovascular Research Laboratories, School of Medical Sciences, University of Bristol, Bristol, United Kingdom
| | - David J Gavaghan
- Computational Biology, Department of Computer Science, University of Oxford, Oxford, United Kingdom
| | - Liudmila Polonchuk
- Pharma Research and Early Development, Innovation Center Basel, F. Hoffmann-La Roche, Basel, Switzerland
| | - Ken Wang
- Pharma Research and Early Development, Innovation Center Basel, F. Hoffmann-La Roche, Basel, Switzerland
| | - Gary R Mirams
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom.
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30
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Owen SF, Liu MH, Kreitzer AC. Thermal constraints on in vivo optogenetic manipulations. Nat Neurosci 2019; 22:1061-1065. [PMID: 31209378 PMCID: PMC6592769 DOI: 10.1038/s41593-019-0422-3] [Citation(s) in RCA: 244] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 05/08/2019] [Indexed: 11/30/2022]
Abstract
A key assumption of optogenetics is that light only affects opsin-expressing neurons. However, illumination invariably heats tissue, and many physiological processes are temperature-sensitive. Commonly used illumination protocols increased the temperature by 0.2-2 °C and suppressed spiking in multiple brain regions. In the striatum, light delivery activated an inwardly rectifying potassium conductance and biased rotational behavior. Thus, careful consideration of light-delivery parameters is required, as even modest intracranial heating can confound interpretation of optogenetic experiments.
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Affiliation(s)
| | - Max H Liu
- Medical Scientist Training Program, University of California, San Francisco, San Francisco, CA, USA
- Neuroscience Graduate Program, UCSF, San Francisco, CA, USA
| | - Anatol C Kreitzer
- Gladstone Institutes, San Francisco, CA, USA.
- Neuroscience Graduate Program, UCSF, San Francisco, CA, USA.
- Department of Neurology, UCSF, San Francisco, CA, USA.
- UCSF Weill Institute for Neurosciences, UCSF, San Francisco, CA, USA.
- Department of Physiology, UCSF, San Francisco, CA, USA.
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31
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Lin H, Jun I, Woo JH, Lee MG, Kim SJ, Nam JH. Temperature-dependent increase in the calcium sensitivity and acceleration of activation of ANO6 chloride channel variants. Sci Rep 2019; 9:6706. [PMID: 31040335 PMCID: PMC6491614 DOI: 10.1038/s41598-019-43162-1] [Citation(s) in RCA: 10] [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: 03/08/2018] [Accepted: 04/12/2019] [Indexed: 02/08/2023] Open
Abstract
Anoctamin-6 (ANO6) belongs to a family of calcium (Ca2+)-activated chloride channels (CaCCs), with three splicing variants (V1, V2, and V5) showing plasma membrane expression. Unlike other CaCCs, ANO6 requires a non-physiological intracellular free calcium concentration ([Ca2+]i > 1 μM) and several minutes for full activation under a whole-cell patch clamp. Therefore, its physiological role as an ion channel is uncertain and it is more commonly considered a Ca2+-dependent phospholipid scramblase. Here, we demonstrate that physiological temperature (37 °C) increases ANO6 Ca2+ sensitivity under a whole-cell patch clamp; V1 was activated by 1 μM [Ca2+]i, whereas V2 and V5 were activated by 300 nM [Ca2+]i. Increasing the temperature to 42 °C led to activation of all ANO6 variants by 100 nM [Ca2+]i. The delay time for activation of the three variants was significantly shortened at 37 °C. Notably, the temperature-dependent Ca2+-sensitisation of ANO6 became insignificant under inside-out patch clamp, suggesting critical roles of unknown cytosolic factors. Unlike channel activity, 27 °C but not 37 °C (physiological temperature) induced the scramblase activity of ANO6 at submicromolar [Ca2+]i (300 nM), irrespective of variant type. Our results reveal a physiological ion conducting property of ANO6 at 37 °C and suggest that ANO6 channel function acts separately from its scramblase activity.
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Affiliation(s)
- Haiyue Lin
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Ikhyun Jun
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
- Department of Pharmacology and Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Joo Han Woo
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju, 38066, Republic of Korea
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Ilsan Dong-gu, Goyang, Gyeonggi-do, 10326, Republic of Korea
| | - Min Goo Lee
- Department of Pharmacology and Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju, 38066, Republic of Korea.
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Ilsan Dong-gu, Goyang, Gyeonggi-do, 10326, Republic of Korea.
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32
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Computational modeling of the effect of temperature variations on human pancreatic β-cell activity. J Therm Biol 2018; 75:69-80. [PMID: 30017054 DOI: 10.1016/j.jtherbio.2018.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/23/2018] [Accepted: 05/24/2018] [Indexed: 11/22/2022]
Abstract
The effect of temperature variations on the pancreatic β-cell activity and the role of different model compartments in temperature sensing have been investigated using a computational modeling approach. The results of our study show that temperature variations by several degrees can change the dynamical states of the β-cell system. In addition, temperature variations can alter the characteristic features of the membrane voltage, which correlates with insulin secretion. Simulation results show that the ion channels such as the L-type calcium, the hERG potassium, sodium channels and the glycolysis pathway are the possible sites for sensing temperature variation. Results indicate that for a small temperature change, even though the frequency and amplitude of electrical activity are altered, the area under the membrane potential curve remains almost unchanged, which implies the existence of a thermoregulatory mechanism for preserving the amount of insulin secretion. Furthermore, the computational analysis shows that the β-cell electrical activity exhibits a bursting pattern in physiological temperature (37 °C) while in vitro studies reported almost the spiking activity at lower temperatures. Since hormone-secreting systems work more efficient in bursting mode, we propose that the pancreatic β-cell works better in the physiological temperature compared with the reference temperature (33 °C).
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Abdelsayed M, Ruprai M, Ruben PC. The efficacy of Ranolazine on E1784K is altered by temperature and calcium. Sci Rep 2018; 8:3643. [PMID: 29483621 PMCID: PMC5827758 DOI: 10.1038/s41598-018-22033-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 02/15/2018] [Indexed: 12/19/2022] Open
Abstract
E1784K is the most common mixed syndrome SCN5a mutation underpinning both Brugada syndrome type 1 (BrS1) and Long-QT syndrome type 3 (LQT3). The charge reversal mutant enhances the late sodium current (INa) passed by the cardiac voltage-gated sodium channel (NaV1.5), delaying cardiac repolarization. Exercise-induced triggers, like elevated temperature and cytosolic calcium, exacerbate E1784K late INa. In this study, we tested the effects of Ranolazine, the late INa blocker, on voltage-dependent and kinetic properties of E1784K at elevated temperature and cytosolic calcium. We used whole-cell patch clamp to measure INa from wild type and E1784K channels expressed in HEK293 cells. At elevated temperature, Ranolazine attenuated gain-of-function in E1784K by decreasing late INa, hyperpolarizing steady-state fast inactivation, and increasing use-dependent inactivation. Both elevated temperature and cytosolic calcium hampered the capacity of Ranolazine to suppress E1784K late INa. In-silico action potential (AP) simulations were done using a modified O'Hara Rudy (ORd) cardiac model. Simulations showed that Ranolazine failed to shorten AP duration, an effect augmented at febrile temperatures. The drug-channel interaction is clearly affected by external triggers, as reported previously with ischemia. Determining drug efficacy under various physiological states in SCN5a cohorts is crucial for accurate management of arrhythmias.
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Affiliation(s)
- Mena Abdelsayed
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Manpreet Ruprai
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Peter C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
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Zhang F, Jara-Oseguera A, Chang TH, Bae C, Hanson SM, Swartz KJ. Heat activation is intrinsic to the pore domain of TRPV1. Proc Natl Acad Sci U S A 2018; 115:E317-E324. [PMID: 29279388 PMCID: PMC5777071 DOI: 10.1073/pnas.1717192115] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The TRPV1 channel is a sensitive detector of pain-producing stimuli, including noxious heat, acid, inflammatory mediators, and vanilloid compounds. Although binding sites for some activators have been identified, the location of the temperature sensor remains elusive. Using available structures of TRPV1 and voltage-activated potassium channels, we engineered chimeras wherein transmembrane regions of TRPV1 were transplanted into the Shaker Kv channel. Here we show that transplanting the pore domain of TRPV1 into Shaker gives rise to functional channels that can be activated by a TRPV1-selective tarantula toxin that binds to the outer pore of the channel. This pore-domain chimera is permeable to Na+, K+, and Ca2+ ions, and remarkably, is also robustly activated by noxious heat. Our results demonstrate that the pore of TRPV1 is a transportable domain that contains the structural elements sufficient for activation by noxious heat.
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Affiliation(s)
- Feng Zhang
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Andres Jara-Oseguera
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Tsg-Hui Chang
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Chanhyung Bae
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Sonya M Hanson
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
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35
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The temperature dependence of the BK channel activity – kinetics, thermodynamics, and long-range correlations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1805-1814. [DOI: 10.1016/j.bbamem.2017.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 05/16/2017] [Accepted: 05/25/2017] [Indexed: 12/20/2022]
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36
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Viana F. TRPA1 channels: molecular sentinels of cellular stress and tissue damage. J Physiol 2017; 594:4151-69. [PMID: 27079970 DOI: 10.1113/jp270935] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/31/2016] [Indexed: 01/08/2023] Open
Abstract
TRPA1 is a non-selective cation channel expressed in mammalian peripheral pain receptors, with a major role in chemonociception. TRPA1 has also been implicated in noxious cold and mechanical pain sensation. TRPA1 has an ancient origin and plays important functions in lower organisms, including thermotaxis, mechanotransduction and modulation of lifespan. Here we highlight the role of TRPA1 as a multipurpose sensor of harmful signals, including toxic bacterial products and UV light, and as a sensor of stress and tissue damage. Sensing roles span beyond the peripheral nervous system to include major barrier tissues: gut, skin and lung. Tissue injury, environmental irritants and microbial pathogens are danger signals that can threaten the health of organisms. These signals lead to the coordinated activation of the nociceptive and the innate immune system to provide a homeostatic response trying to re-establish physiological conditions including tissue repair. Activation of TRPA1 participates in protective neuroimmune interactions at multiple levels, sensing ROS and bacterial products and triggering the release of neuropeptides. However, an exaggerated response to danger signals is maladaptive and can lead to the development of chronic inflammatory conditions.
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Affiliation(s)
- Félix Viana
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Alicante, Spain
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Oliver KL, Franceschetti S, Milligan CJ, Muona M, Mandelstam SA, Canafoglia L, Boguszewska-Chachulska AM, Korczyn AD, Bisulli F, Di Bonaventura C, Ragona F, Michelucci R, Ben-Zeev B, Straussberg R, Panzica F, Massano J, Friedman D, Crespel A, Engelsen BA, Andermann F, Andermann E, Spodar K, Lasek-Bal A, Riguzzi P, Pasini E, Tinuper P, Licchetta L, Gardella E, Lindenau M, Wulf A, Møller RS, Benninger F, Afawi Z, Rubboli G, Reid CA, Maljevic S, Lerche H, Lehesjoki AE, Petrou S, Berkovic SF. Myoclonus epilepsy and ataxia due to KCNC1 mutation: Analysis of 20 cases and K + channel properties. Ann Neurol 2017; 81:677-689. [PMID: 28380698 DOI: 10.1002/ana.24929] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 03/31/2017] [Accepted: 03/31/2017] [Indexed: 12/24/2022]
Abstract
OBJECTIVE To comprehensively describe the new syndrome of myoclonus epilepsy and ataxia due to potassium channel mutation (MEAK), including cellular electrophysiological characterization of observed clinical improvement with fever. METHODS We analyzed clinical, electroclinical, and neuroimaging data for 20 patients with MEAK due to recurrent KCNC1 p.R320H mutation. In vitro electrophysiological studies were conducted using whole cell patch-clamp to explore biophysical properties of wild-type and mutant KV 3.1 channels. RESULTS Symptoms began at between 3 and 15 years of age (median = 9.5), with progressively severe myoclonus and rare tonic-clonic seizures. Ataxia was present early, but quickly became overshadowed by myoclonus; 10 patients were wheelchair-bound by their late teenage years. Mild cognitive decline occurred in half. Early death was not observed. Electroencephalogram (EEG) showed generalized spike and polyspike wave discharges, with documented photosensitivity in most. Polygraphic EEG-electromyographic studies demonstrated a cortical origin for myoclonus and striking coactivation of agonist and antagonist muscles. Magnetic resonance imaging revealed symmetrical cerebellar atrophy, which appeared progressive, and a prominent corpus callosum. Unexpectedly, transient clinical improvement with fever was noted in 6 patients. To explore this, we performed high-temperature in vitro recordings. At elevated temperatures, there was a robust leftward shift in activation of wild-type KV 3.1, increasing channel availability. INTERPRETATION MEAK has a relatively homogeneous presentation, resembling Unverricht-Lundborg disease, despite the genetic and biological basis being quite different. A remarkable improvement with fever may be explained by the temperature-dependent leftward shift in activation of wild-type KV 3.1 subunit-containing channels, which would counter the loss of function observed for mutant channels, highlighting KCNC1 as a potential target for precision therapeutics. Ann Neurol 2017;81:677-689.
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Affiliation(s)
- Karen L Oliver
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Silvana Franceschetti
- Department of Neurophysiology, C. Besta Neurological Institute IRCCS Foundation, Milan, Italy
| | - Carol J Milligan
- Ion Channels and Disease Group, Epilepsy Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Mikko Muona
- Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland.,Folkhälsan Institute of Genetics, Helsinki, Finland.,Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.,Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Simone A Mandelstam
- Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.,Departments of Paediatrics and Radiology, University of Melbourne, Melbourne, Victoria, Australia.,Department of Medical Imaging, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Laura Canafoglia
- Department of Neurophysiology, C. Besta Neurological Institute IRCCS Foundation, Milan, Italy
| | | | - Amos D Korczyn
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Francesca Bisulli
- IRCCS-Institute of Neurological Sciences of Bologna, Bologna, Italy.,Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Carlo Di Bonaventura
- Department of Neurological Sciences, University of Rome, La Sapienza, Rome, Italy
| | - Francesca Ragona
- Department of Pediatric Neuroscience, C. Besta Neurological Institute IRCCS Foundation, Milan, Italy
| | - Roberto Michelucci
- IRCCS-Institute of Neurological Sciences of Bologna, Bologna, Italy.,Unit of Neurology, Bellaria Hospital, Bologna, Italy
| | - Bruria Ben-Zeev
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Ramat Gan, Israel
| | - Rachel Straussberg
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Epilepsy Unit, Schneider Children's Medical Center of Israel, Petah Tikvah, Israel
| | - Ferruccio Panzica
- Department of Neurophysiology, C. Besta Neurological Institute IRCCS Foundation, Milan, Italy
| | - João Massano
- Department of Neurology, Hospital Pedro Hispano/ULS Matosinhos, Senhora da Hora, Portugal.,Department of Clinical Neurosciences and Mental Health, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Daniel Friedman
- Comprehensive Epilepsy Center, New York University Langone Medical Center, New York, NY
| | - Arielle Crespel
- Epilepsy Unit, Gui de Chauliac Hospital, Montpellier, France
| | - Bernt A Engelsen
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Frederick Andermann
- Epilepsy Research Group, Montreal Neurological Hospital and Institute, Montreal, Quebec, Canada.,Departments of Neurology & Neurosurgery and Paediatrics, McGill University, Montreal, Quebec, Canada
| | - Eva Andermann
- Neurogenetics Unit and Epilepsy Research Group, Montreal Neurological Hospital and Institute, Montreal, Quebec, Canada.,Departments of Neurology & Neurosurgery and Human Genetics, McGill University, Montreal, Quebec, Canada
| | | | - Anetta Lasek-Bal
- High School of Science, Medical University of Silesia, Department of Neurology, Upper Silesian Medical Center, Katowice, Poland
| | - Patrizia Riguzzi
- IRCCS-Institute of Neurological Sciences of Bologna, Bologna, Italy.,Unit of Neurology, Bellaria Hospital, Bologna, Italy
| | - Elena Pasini
- IRCCS-Institute of Neurological Sciences of Bologna, Bologna, Italy.,Unit of Neurology, Bellaria Hospital, Bologna, Italy
| | - Paolo Tinuper
- IRCCS-Institute of Neurological Sciences of Bologna, Bologna, Italy.,Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Laura Licchetta
- IRCCS-Institute of Neurological Sciences of Bologna, Bologna, Italy.,Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Elena Gardella
- Danish Epilepsy Center, Dianalund, Denmark.,Institute for Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Matthias Lindenau
- Department of Neurology and Epileptology, Epilepsy Center Hamburg-Alsterdorf, Hamburg, Germany
| | - Annette Wulf
- Department of Neurology and Epileptology, Epilepsy Center Hamburg-Alsterdorf, Hamburg, Germany
| | - Rikke S Møller
- Danish Epilepsy Center, Dianalund, Denmark.,Institute for Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Felix Benninger
- Department of Neurology, Rabin Medical Center, Beilinson Hospital, Petah Tikvah, Israel
| | - Zaid Afawi
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Guido Rubboli
- IRCCS-Institute of Neurological Sciences of Bologna, Bologna, Italy.,Danish Epilepsy Center, Filadelfia/University of Copenhagen, Dianalund, Denmark
| | - Christopher A Reid
- Ion Channels and Disease Group, Epilepsy Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Snezana Maljevic
- Ion Channels and Disease Group, Epilepsy Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,University of Tübingen, Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, Tübingen, Germany
| | - Holger Lerche
- University of Tübingen, Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, Tübingen, Germany
| | - Anna-Elina Lehesjoki
- Folkhälsan Institute of Genetics, Helsinki, Finland.,Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.,Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Steven Petrou
- Ion Channels and Disease Group, Epilepsy Division, Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Centre for Neural Engineering, Department of Electrical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Samuel F Berkovic
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
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Rungta RL, Osmanski BF, Boido D, Tanter M, Charpak S. Light controls cerebral blood flow in naive animals. Nat Commun 2017; 8:14191. [PMID: 28139643 PMCID: PMC5290324 DOI: 10.1038/ncomms14191] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 12/07/2016] [Indexed: 01/05/2023] Open
Abstract
Optogenetics is increasingly used to map brain activation using techniques that rely on functional hyperaemia, such as opto-fMRI. Here we test whether light stimulation protocols similar to those commonly used in opto-fMRI or to study neurovascular coupling modulate blood flow in mice that do not express light sensitive proteins. Combining two-photon laser scanning microscopy and ultrafast functional ultrasound imaging, we report that in the naive mouse brain, light per se causes a calcium decrease in arteriolar smooth muscle cells, leading to pronounced vasodilation, without excitation of neurons and astrocytes. This photodilation is reversible, reproducible and energy-dependent, appearing at about 0.5 mJ. These results impose careful consideration on the use of photo-activation in studies involving blood flow regulation, as well as in studies requiring prolonged and repetitive stimulations to correct cellular defects in pathological models. They also suggest that light could be used to locally increase blood flow in a controlled fashion. Combination of optogenetics and BOLD fMRI is routinely used to map neuronal activity upon photostimulation. Here the authors show that light, shone at intensities used in optogenetic studies, dilates vessels and increases blood flow independently of exogenous light-sensitive proteins in the mouse brain.
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Affiliation(s)
- Ravi L Rungta
- INSERM U1128, Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, Paris 75006, France
| | - Bruno-Félix Osmanski
- INSERM U1128, Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, Paris 75006, France
| | - Davide Boido
- INSERM U1128, Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, Paris 75006, France
| | - Mickael Tanter
- Institut Langevin, Espci Paris, CNRS UMR 7587, INSERM U979, PSL Research University, 17 rue Moreau, Paris 75012, France
| | - Serge Charpak
- INSERM U1128, Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, Paris 75006, France
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Rabbitt RD, Brichta AM, Tabatabaee H, Boutros PJ, Ahn J, Della Santina CC, Poppi LA, Lim R. Heat pulse excitability of vestibular hair cells and afferent neurons. J Neurophysiol 2016; 116:825-43. [PMID: 27226448 DOI: 10.1152/jn.00110.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/24/2016] [Indexed: 11/22/2022] Open
Abstract
In the present study we combined electrophysiology with optical heat pulse stimuli to examine thermodynamics of membrane electrical excitability in mammalian vestibular hair cells and afferent neurons. We recorded whole cell currents in mammalian type II vestibular hair cells using an excised preparation (mouse) and action potentials (APs) in afferent neurons in vivo (chinchilla) in response to optical heat pulses applied to the crista (ΔT ≈ 0.25°C per pulse). Afferent spike trains evoked by heat pulse stimuli were diverse and included asynchronous inhibition, asynchronous excitation, and/or phase-locked APs synchronized to each infrared heat pulse. Thermal responses of membrane currents responsible for APs in ganglion neurons were strictly excitatory, with Q10 ≈ 2. In contrast, hair cells responded with a mix of excitatory and inhibitory currents. Excitatory hair cell membrane currents included a thermoelectric capacitive current proportional to the rate of temperature rise (dT/dt) and an inward conduction current driven by ΔT An iberiotoxin-sensitive inhibitory conduction current was also evoked by ΔT, rising in <3 ms and decaying with a time constant of ∼24 ms. The inhibitory component dominated whole cell currents in 50% of hair cells at -68 mV and in 67% of hair cells at -60 mV. Responses were quantified and described on the basis of first principles of thermodynamics. Results identify key molecular targets underlying heat pulse excitability in vestibular sensory organs and provide quantitative methods for rational application of optical heat pulses to examine protein biophysics and manipulate cellular excitability.
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Affiliation(s)
- Richard D Rabbitt
- Departments of Bioengineering and Otolaryngology, University of Utah, Salt Lake City, Utah;
| | - Alan M Brichta
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Hessam Tabatabaee
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Peter J Boutros
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - JoongHo Ahn
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Charles C Della Santina
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Lauren A Poppi
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Rebecca Lim
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
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40
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Gregorio-Teruel L, Valente P, Liu B, Fernández-Ballester G, Qin F, Ferrer-Montiel A. The Integrity of the TRP Domain Is Pivotal for Correct TRPV1 Channel Gating. Biophys J 2016; 109:529-41. [PMID: 26244735 DOI: 10.1016/j.bpj.2015.06.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 06/18/2015] [Accepted: 06/22/2015] [Indexed: 01/19/2023] Open
Abstract
Transient receptor potential vanilloid subtype I (TRPV1) is a thermosensory ion channel that is also gated by chemical substances such as vanilloids. Adjacent to the channel gate, this polymodal thermoTRP channel displays a TRP domain, referred to as AD1, that plays a role in subunit association and channel gating. Previous studies have shown that swapping the AD1 in TRPV1 with the cognate from the TRPV2 channel (AD2) reduces protein expression and produces a nonfunctional chimeric channel (TRPV1-AD2). Here, we used a stepwise, sequential, cumulative site-directed mutagenesis approach, based on rebuilding the AD1 domain in the TRPV1-AD2 chimera, to unveil the minimum number of amino acids needed to restore protein expression and polymodal channel activity. Unexpectedly, we found that virtually full restitution of the AD1 sequence is required to reinstate channel expression and responses to capsaicin, temperature, and voltage. This strategy identified E692, R701, and T704 in the TRP domain as important for TRPV1 activity. Even conservative mutagenesis at these sites (E692D/R701K/T704S) impaired channel expression and abolished TRPV1 activity. However, the sole mutation of these positions in the TRPV1-AD2 chimera (D692E/K701R/S704T) was not sufficient to rescue channel gating, implying that other residues in the TRP domain are necessary to endow activity to TRPV1-AD2. A biophysical analysis of a functional chimera suggested that mutations in the TRP domain raised the energetics of channel gating by altering the coupling of stimuli sensing and pore opening. These findings indicate that inter- and/or intrasubunit interactions in the TRP domain are essential for correct TRPV1 gating.
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Affiliation(s)
- Lucia Gregorio-Teruel
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Alicante, Spain
| | - Pierluigi Valente
- Department of Experimental Medicine, Section of Physiology, University of Genova, Genova, Italy
| | - Beiying Liu
- Department of Physiology and Biophysical Sciences, State University of New York, Buffalo, New York
| | | | - Feng Qin
- Department of Physiology and Biophysical Sciences, State University of New York, Buffalo, New York
| | - Antonio Ferrer-Montiel
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Alicante, Spain.
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Jara-Oseguera A, Bae C, Swartz KJ. An external sodium ion binding site controls allosteric gating in TRPV1 channels. eLife 2016; 5. [PMID: 26882503 PMCID: PMC4764576 DOI: 10.7554/elife.13356] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/28/2016] [Indexed: 12/11/2022] Open
Abstract
TRPV1 channels in sensory neurons are integrators of painful stimuli and heat, yet how they integrate diverse stimuli and sense temperature remains elusive. Here, we show that external sodium ions stabilize the TRPV1 channel in a closed state, such that removing the external ion leads to channel activation. In studying the underlying mechanism, we find that the temperature sensors in TRPV1 activate in two steps to favor opening, and that the binding of sodium to an extracellular site exerts allosteric control over temperature-sensor activation and opening of the pore. The binding of a tarantula toxin to the external pore also exerts control over temperature-sensor activation, whereas binding of vanilloids influences temperature-sensitivity by largely affecting the open/closed equilibrium. Our results reveal a fundamental role of the external pore in the allosteric control of TRPV1 channel gating and provide essential constraints for understanding how these channels can be tuned by diverse stimuli. DOI:http://dx.doi.org/10.7554/eLife.13356.001 Humans and other mammals sense elevated heat and other painful stimuli via a sensory ion channel protein called TRPV1. Ion channels create pores in the outer membrane of cells and act as gates that open and close to regulate the flow of ions into and out of cells. This flow of ions generates electrical signals that sensory neurons use to communicate information about the environment to the brain. The TRPV1 channel is opened by heat, but also by venom toxins, acid and the active ingredient in hot chilli peppers. The fluid that surrounds animal cells often contains high levels of sodium ions, and these ions flow through TRPV1 channels when they are open. Also, when sodium ions are removed from the fluid surrounding a cell, TRPV1 channels will spontaneously open. It is not known why this happens, but it suggests that sodium ions help to regulate the activity of the TRPV1 channel, and despite having been extensively studied, it remains unclear how this channel senses temperature and responds to other harmful stimuli. Jara-Oseguera et al. have now investigated the role of sodium ions in activating TRPV1 in cells grown in the laboratory. The experiments involved a technique that records the movement of ions through TRPV1 channels in the cell surface membrane while exposing the cell to various stimuli that open or close the channels. The results showed that TRPV1 contains an important site on its outer surface that binds sodium ions and fine-tunes the channel’s properties. This enables the channel to be activated by potentially damaging temperatures. Further analysis revealed that TRPV1 undergoes at least two distinct physical changes in response to heat and that the binding of sodium ions to the channel’s outer structure regulates one of these changes. Jara-Oseguera et al. went on to discover that the binding of a tarantula toxin to the outer surface of TRPV1 renders the channel insensitive to changes in temperature. These findings suggest that structural changes to the external part of this channel protein are closely associated with its ability to sense temperature, possibly because this region of the protein is directly responsible for detecting changes in temperature. These findings shed light on how this channel detects and responds to dangerously high temperatures, as well to other harmful stimuli. An aim for future studies is to pinpoint the specific regions of the protein that form the sodium-binding sites and to test the hypothesis that temperature sensors are located on the outer surface of the protein. DOI:http://dx.doi.org/10.7554/eLife.13356.002
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Affiliation(s)
- Andres Jara-Oseguera
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Chanhyung Bae
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
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42
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Thermosensation and longevity. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2015; 201:857-67. [PMID: 26101089 DOI: 10.1007/s00359-015-1021-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Revised: 06/06/2015] [Accepted: 06/08/2015] [Indexed: 12/25/2022]
Abstract
Temperature has profound effects on behavior and aging in both poikilotherms and homeotherms. To thrive under the ever fluctuating environmental temperatures, animals have evolved sophisticated mechanisms to sense and adapt to temperature changes. Animals sense temperature through various molecular thermosensors, such as thermosensitive transient receptor potential (TRP) channels expressed in neurons, keratinocytes, and intestine. These evolutionarily conserved thermosensitive TRP channels feature distinct activation thresholds, thereby covering a wide spectrum of ambient temperature. Temperature changes trigger complex thermosensory behaviors. Due to the simplicity of the nervous system in model organisms such as Caenorhabditis elegans and Drosophila, the mechanisms of thermosensory behaviors in these species have been extensively studied at the circuit and molecular levels. While much is known about temperature regulation of behavior, it remains largely unclear how temperature affects aging. Recent studies in C. elegans demonstrate that temperature modulation of longevity is not simply a passive thermodynamic phenomenon as suggested by the rate-of-living theory, but rather a process that is actively regulated by genes, including those encoding thermosensitive TRP channels. In this review, we discuss our current understanding of thermosensation and its role in aging.
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Negative and positive temperature dependence of potassium leak in MscS mutants: Implications for understanding thermosensitive channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1678-86. [PMID: 25958301 DOI: 10.1016/j.bbamem.2015.04.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 04/24/2015] [Accepted: 04/29/2015] [Indexed: 01/30/2023]
Abstract
Bacterial mechanosensitive channel of small conductance (MscS) is a protein, whose activity is modulated by membrane tension, voltage and cytoplasmic crowding. MscS is a homoheptamer and each monomer consists of three transmembrane helices (TM1-3). Hydrophobic pore of the channel is made of TM3s surrounded by peripheral TM1/2s. MscS gating is a complex process, which involves opening and inactivation in response to the increase of membrane tension. A number of MscS mutants were isolated. Among them mutants affecting gating have been found including gain-of-function (GOF) and loss-of-function (LOF) that open at lower or at higher thresholds, respectively. Previously, using an in vivo screen we isolated multiple MscS mutants that leak potassium and some of them were GOF or LOF. Here we show that for a subset of these mutants K+ leak is negatively (NTD) or positively (PTD) temperature dependent. We show that temperature reliance of these mutants does not depend on how MS gating is affected by a particular mutation. Instead, we argue that NTD or PTD leak is due to the opposite allosteric coupling of the structures that determine the temperature dependence to the channel gate. In PTD mutants an increased hydration of the pore vestibule is directly coupled to the increase in the channel conductance. In NTD mutants, at higher temperatures an increased hydration of peripheral structures leads to complete separation of TM3 and a pore collapse.
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Laursen WJ, Anderson EO, Hoffstaetter LJ, Bagriantsev SN, Gracheva EO. Species-specific temperature sensitivity of TRPA1. Temperature (Austin) 2015; 2:214-26. [PMID: 27227025 PMCID: PMC4843866 DOI: 10.1080/23328940.2014.1000702] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/16/2014] [Accepted: 12/16/2014] [Indexed: 11/25/2022] Open
Abstract
Transient receptor potential ankyrin 1 (TRPA1) is a polymodal ion channel sensitive to temperature and chemical stimuli. The importance of temperature and aversive chemical detection for survival has driven the evolutionary diversity of TRPA1 sensitivity. This diversity can be observed in the various roles of TRPA1 in different species, where it is proposed to act as a temperature-insensitive chemosensor, a heat transducer, a noxious cold transducer, or a detector of low-intensity heat for prey localization. Exploring the variation of TRPA1 functions among species provides evolutionary insight into molecular mechanisms that fine-tune thermal and chemical sensitivity, and offers an opportunity to address basic principles of temperature gating in ion channels. A decade of research has yielded a number of hypotheses describing physiological roles of TRPA1, modulators of its activity, and biophysical principles of gating. This review surveys the diversity of TRPA1 adaptations across evolutionary taxa and explores possible mechanisms of TRPA1 activation.
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Affiliation(s)
- Willem J Laursen
- Department of Cellular and Molecular Physiology; Yale University School of Medicine; New Haven, CT, USA; Program in Cellular Neuroscience; Neurodegeneration and Repair; Yale University School of Medicine; New Haven, CT, USA
| | - Evan O Anderson
- Department of Cellular and Molecular Physiology; Yale University School of Medicine ; New Haven, CT, USA
| | - Lydia J Hoffstaetter
- Department of Cellular and Molecular Physiology; Yale University School of Medicine; New Haven, CT, USA; Program in Cellular Neuroscience; Neurodegeneration and Repair; Yale University School of Medicine; New Haven, CT, USA
| | - Sviatoslav N Bagriantsev
- Department of Cellular and Molecular Physiology; Yale University School of Medicine ; New Haven, CT, USA
| | - Elena O Gracheva
- Department of Cellular and Molecular Physiology; Yale University School of Medicine; New Haven, CT, USA; Program in Cellular Neuroscience; Neurodegeneration and Repair; Yale University School of Medicine; New Haven, CT, USA
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DeCaen PG, Takahashi Y, Krulwich TA, Ito M, Clapham DE. Ionic selectivity and thermal adaptations within the voltage-gated sodium channel family of alkaliphilic Bacillus. eLife 2014; 3. [PMID: 25385530 PMCID: PMC4225499 DOI: 10.7554/elife.04387] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 10/02/2014] [Indexed: 12/19/2022] Open
Abstract
Entry and extrusion of cations are essential processes in living cells. In alkaliphilic prokaryotes, high external pH activates voltage-gated sodium channels (Nav), which allows Na(+) to enter and be used as substrate for cation/proton antiporters responsible for cytoplasmic pH homeostasis. Here, we describe a new member of the prokaryotic voltage-gated Na(+) channel family (NsvBa; <underline>N</underline>on-<underline>s</underline>elective <underline>v</underline>oltage-gated, <underline>B</underline>acillus <underline>a</underline>lcalophilus) that is nonselective among Na(+), Ca(2+) and K(+) ions. Mutations in NsvBa can convert the nonselective filter into one that discriminates for Na(+) or divalent cations. Gain-of-function experiments demonstrate the portability of ion selectivity with filter mutations to other Bacillus Nav channels. Increasing pH and temperature shifts their activation threshold towards their native resting membrane potential. Furthermore, we find drugs that target Bacillus Nav channels also block the growth of the bacteria. This work identifies some of the adaptations to achieve ion discrimination and gating in Bacillus Nav channels.
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Affiliation(s)
- Paul G DeCaen
- Department of Cardiology, Howard Hughes Medical Institute, Boston Children's Hospital, Boston, United States
| | - Yuka Takahashi
- Graduate School of Life Sciences, Toyo University, Gunma, Japan
| | - Terry A Krulwich
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Masahiro Ito
- Graduate School of Life Sciences, Toyo University, Gunma, Japan
| | - David E Clapham
- Department of Cardiology, Howard Hughes Medical Institute, Boston Children's Hospital, Boston, United States
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