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Carlton AJ, Jeng JY, Grandi FC, De Faveri F, Amariutei AE, De Tomasi L, O'Connor A, Johnson SL, Furness DN, Brown SDM, Ceriani F, Bowl MR, Mustapha M, Marcotti W. BAI1 localizes AMPA receptors at the cochlear afferent post-synaptic density and is essential for hearing. Cell Rep 2024; 43:114025. [PMID: 38564333 DOI: 10.1016/j.celrep.2024.114025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 01/25/2024] [Accepted: 03/15/2024] [Indexed: 04/04/2024] Open
Abstract
Type I spiral ganglion neurons (SGNs) convey sound information to the central auditory pathway by forming synapses with inner hair cells (IHCs) in the mammalian cochlea. The molecular mechanisms regulating the formation of the post-synaptic density (PSD) in the SGN afferent terminals are still unclear. Here, we demonstrate that brain-specific angiogenesis inhibitor 1 (BAI1) is required for the clustering of AMPA receptors GluR2-4 (glutamate receptors 2-4) at the PSD. Adult Bai1-deficient mice have functional IHCs but fail to transmit information to the SGNs, leading to highly raised hearing thresholds. Despite the almost complete absence of AMPA receptor subunits, the SGN fibers innervating the IHCs do not degenerate. Furthermore, we show that AMPA receptors are still expressed in the cochlea of Bai1-deficient mice, highlighting a role for BAI1 in trafficking or anchoring GluR2-4 to the PSDs. These findings identify molecular and functional mechanisms required for sound encoding at cochlear ribbon synapses.
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Affiliation(s)
- Adam J Carlton
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Jing-Yi Jeng
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Fiorella C Grandi
- Sorbonne Université, INSERM, Institute de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | | | - Ana E Amariutei
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Lara De Tomasi
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Andrew O'Connor
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Stuart L Johnson
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK; Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK
| | - David N Furness
- School of Life Sciences, Keele University, Keele ST5 5BG, UK
| | - Steve D M Brown
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Federico Ceriani
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Michael R Bowl
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire OX11 0RD, UK
| | - Mirna Mustapha
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK; Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK
| | - Walter Marcotti
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK; Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK.
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Carlton AJ, Jeng J, Grandi FC, De Faveri F, Ceriani F, De Tomasi L, Underhill A, Johnson SL, Legan KP, Kros CJ, Richardson GP, Mustapha M, Marcotti W. A critical period of prehearing spontaneous Ca 2+ spiking is required for hair-bundle maintenance in inner hair cells. EMBO J 2023; 42:e112118. [PMID: 36594367 PMCID: PMC9929643 DOI: 10.15252/embj.2022112118] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 11/22/2022] [Accepted: 11/28/2022] [Indexed: 01/04/2023] Open
Abstract
Sensory-independent Ca2+ spiking regulates the development of mammalian sensory systems. In the immature cochlea, inner hair cells (IHCs) fire spontaneous Ca2+ action potentials (APs) that are generated either intrinsically or by intercellular Ca2+ waves in the nonsensory cells. The extent to which either or both of these Ca2+ signalling mechansims are required for IHC maturation is unknown. We find that intrinsic Ca2+ APs in IHCs, but not those elicited by Ca2+ waves, regulate the maturation and maintenance of the stereociliary hair bundles. Using a mouse model in which the potassium channel Kir2.1 is reversibly overexpressed in IHCs (Kir2.1-OE), we find that IHC membrane hyperpolarization prevents IHCs from generating intrinsic Ca2+ APs but not APs induced by Ca2+ waves. Absence of intrinsic Ca2+ APs leads to the loss of mechanoelectrical transduction in IHCs prior to hearing onset due to progressive loss or fusion of stereocilia. RNA-sequencing data show that pathways involved in morphogenesis, actin filament-based processes, and Rho-GTPase signaling are upregulated in Kir2.1-OE mice. By manipulating in vivo expression of Kir2.1 channels, we identify a "critical time period" during which intrinsic Ca2+ APs in IHCs regulate hair-bundle function.
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Affiliation(s)
| | - Jing‐Yi Jeng
- School of BiosciencesUniversity of SheffieldSheffieldUK
| | | | | | | | | | | | - Stuart L Johnson
- School of BiosciencesUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
| | - Kevin P Legan
- School of Life SciencesUniversity of Sussex, FalmerBrightonUK
| | - Corné J Kros
- School of Life SciencesUniversity of Sussex, FalmerBrightonUK
| | | | - Mirna Mustapha
- School of BiosciencesUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
| | - Walter Marcotti
- School of BiosciencesUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
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3
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Jeng JY, Carlton AJ, Goodyear RJ, Chinowsky C, Ceriani F, Johnson SL, Sung TC, Dayn Y, Richardson GP, Bowl MR, Brown SD, Manor U, Marcotti W. AAV-mediated rescue of Eps8 expression in vivo restores hair-cell function in a mouse model of recessive deafness. Mol Ther Methods Clin Dev 2022; 26:355-370. [PMID: 36034774 PMCID: PMC9382420 DOI: 10.1016/j.omtm.2022.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 07/15/2022] [Indexed: 11/24/2022]
Abstract
The transduction of acoustic information by hair cells depends upon mechanosensitive stereociliary bundles that project from their apical surface. Mutations or absence of the stereociliary protein EPS8 cause deafness in humans and mice, respectively. Eps8 knockout mice (Eps8 -/- ) have hair cells with immature stereocilia and fail to become sensory receptors. Here, we show that exogenous delivery of Eps8 using Anc80L65 in P1-P2 Eps8 -/- mice in vivo rescued the hair bundle structure of apical-coil hair cells. Rescued hair bundles correctly localize EPS8, WHIRLIN, MYO15, and BAIAP2L2, and generate normal mechanoelectrical transducer currents. Inner hair cells with normal-looking stereocilia re-expressed adult-like basolateral ion channels (BK and KCNQ4) and have normal exocytosis. The number of hair cells undergoing full recovery was not sufficient to rescue hearing in Eps8 -/- mice. Adeno-associated virus (AAV)-transduction of P3 apical-coil and P1-P2 basal-coil hair cells does not rescue hair cells, nor does Anc80L65-Eps8 delivery in adult Eps8 -/- mice. We propose that AAV-induced gene-base therapy is an efficient strategy to recover the complex hair-cell defects in Eps8 -/- mice. However, this therapeutic approach may need to be performed in utero since, at postnatal ages, Eps8 -/- hair cells appear to have matured or accumulated damage beyond the point of repair.
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Affiliation(s)
- Jing-Yi Jeng
- School of Bioscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Adam J. Carlton
- School of Bioscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Richard J. Goodyear
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Colbie Chinowsky
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Federico Ceriani
- School of Bioscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Stuart L. Johnson
- School of Bioscience, University of Sheffield, Sheffield S10 2TN, UK
- Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK
| | - Tsung-Chang Sung
- Transgenic Core, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Yelena Dayn
- Transgenic Core, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Guy P. Richardson
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Michael R. Bowl
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire OX11 0RD UK
| | - Steve D.M. Brown
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire OX11 0RD UK
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Walter Marcotti
- School of Bioscience, University of Sheffield, Sheffield S10 2TN, UK
- Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK
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4
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Spaiardi P, Marcotti W, Masetto S, Johnson SL. Signal transmission in mature mammalian vestibular hair cells. Front Cell Neurosci 2022; 16:806913. [PMID: 35936492 PMCID: PMC9353129 DOI: 10.3389/fncel.2022.806913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
The maintenance of balance and gaze relies on the faithful and rapid signaling of head movements to the brain. In mammals, vestibular organs contain two types of sensory hair cells, type-I and type-II, which convert the head motion-induced movement of their hair bundles into a graded receptor potential that drives action potential activity in their afferent fibers. While signal transmission in both hair cell types involves Ca2+-dependent quantal release of glutamate at ribbon synapses, type-I cells appear to also exhibit a non-quantal mechanism that is believed to increase transmission speed. However, the reliance of mature type-I hair cells on non-quantal transmission remains unknown. Here we investigated synaptic transmission in mammalian utricular hair cells using patch-clamp recording of Ca2+ currents and changes in membrane capacitance (ΔCm). We found that mature type-II hair cells showed robust exocytosis with a high-order dependence on Ca2+ entry. By contrast, exocytosis was approximately 10 times smaller in type-I hair cells. Synaptic vesicle exocytosis was largely absent in mature vestibular hair cells of CaV1.3 (CaV1.3−/−) and otoferlin (Otof−/−) knockout mice. Even though Ca2+-dependent exocytosis was small in type-I hair cells of wild-type mice, or absent in CaV1.3−/− and Otof−/−mice, these cells were able to drive action potential activity in the postsynaptic calyces. This supports a functional role for non-quantal synaptic transmission in type-I cells. The large vesicle pools in type-II cells would facilitate sustained transmission of tonic or low-frequency signals. In type-I cells, the restricted vesicle pool size, together with a rapid non-quantal mechanism, could allow them to sustain high-frequency phasic signal transmission at their specialized large calyceal synapses.
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Affiliation(s)
- Paolo Spaiardi
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Walter Marcotti
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
- Sheffield Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom
| | - Sergio Masetto
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
| | - Stuart L. Johnson
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
- Sheffield Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom
- *Correspondence: Stuart L. Johnson
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5
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Manca M, Yen P, Spaiardi P, Russo G, Giunta R, Johnson SL, Marcotti W, Masetto S. Current Response in Ca V 1.3 -/- Mouse Vestibular and Cochlear Hair Cells. Front Neurosci 2021; 15:749483. [PMID: 34955713 PMCID: PMC8694397 DOI: 10.3389/fnins.2021.749483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 11/01/2021] [Indexed: 11/24/2022] Open
Abstract
Signal transmission by sensory auditory and vestibular hair cells relies upon Ca2+-dependent exocytosis of glutamate. The Ca2+ current in mammalian inner ear hair cells is predominantly carried through CaV1.3 voltage-gated Ca2+ channels. Despite this, CaV1.3 deficient mice (CaV1.3–/–) are deaf but do not show any obvious vestibular phenotype. Here, we compared the Ca2+ current (ICa) in auditory and vestibular hair cells from wild-type and CaV1.3–/– mice, to assess whether differences in the size of the residual ICa could explain, at least in part, the two phenotypes. Using 5 mM extracellular Ca2+ and near-body temperature conditions, we investigated the cochlear primary sensory receptors inner hair cells (IHCs) and both type I and type II hair cells of the semicircular canals. We found that the residual ICa in both auditory and vestibular hair cells from CaV1.3–/– mice was less than 20% (12–19%, depending on the hair cell type and age investigated) compared to controls, indicating a comparable expression of CaV1.3 Ca2+ channels in both sensory organs. We also showed that, different from IHCs, type I and type II hair cells from CaV1.3–/– mice were able to acquire the adult-like K+ current profile in their basolateral membrane. Intercellular K+ accumulation was still present in CaV1.3–/– mice during IK,L activation, suggesting that the K+-based, non-exocytotic, afferent transmission is still functional in these mice. This non-vesicular mechanism might contribute to the apparent normal vestibular functions in CaV1.3–/– mice.
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Affiliation(s)
- Marco Manca
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy.,School of Biosciences, University of Sheffield, Sheffield, United Kingdom
| | - Piece Yen
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
| | - Paolo Spaiardi
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Giancarlo Russo
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Roberta Giunta
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Stuart L Johnson
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom.,Sheffield Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom
| | - Walter Marcotti
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom.,Sheffield Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom
| | - Sergio Masetto
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
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6
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Lees B, Bose R, Donahue EE, Johnson SL, Naumann RW. COVID19 Pandemic Impact on Same-Day Discharge Rates after Minimally Invasive Surgery for Endometrial Cancer. J Minim Invasive Gynecol 2021. [PMCID: PMC8518356 DOI: 10.1016/j.jmig.2021.09.504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Study Objective To determine if the COVID19 pandemic increased the rate of same-day discharge (SDD) after minimally invasive surgery (MIS) for endometrial cancer. Design Retrospective cohort study of patients undergoing MIS hysterectomy for endometrial cancer for the six months before and after the COVID19 restrictions went into place on March 17, 2020. Setting Robotic or laparoscopic procedure in the low dorsal lithotomy position. Arms were tucked and padded at their sides. Patients or Participants 166 patients underwent a MIS procedure for the indication of endometrial cancer at a large, academic institution from September 1, 2019, through October 1, 2020. 80 patients prior to the implementation of the COVID19 restrictions and 86 patients after. Interventions COVID19 pandemic with visitor restrictions and hospital policy changes placed on March 17, 2020. Measurements and Main Results SDD rate was increased following the start of the COVID19 pandemic (40% vs 58%, p= 0.02). There were no differences between the two groups in regard to operative time (p= 0.07), estimated blood loss (EBL) (p= 0.21), uterine weight (p= 0.12), age (p= 0.06), BMI (p=0.42), or surgery start time (p= 0.15). In a multivariable logistic regression model, subjects in the post COVID19 group had a 3.08 (95% CI: 1.40, 6.74, p= 0.01) higher odds of SDD than those in the pre COVID19 group. There was no difference in 30-day readmission rates (7.5% vs 5.8%, p=0.66). Conclusion With no additional interventions from a surgical standpoint, the start of the COVID19 pandemic improved SDD rates. The reason for this is speculative but may be related to patient and physician desire to keep patients out of the hospital and may provide further evidence that subjective reasons lead to an increase in hospital length of stay.
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Maklar J, Windsor YW, Nicholson CW, Puppin M, Walmsley P, Esposito V, Porer M, Rittmann J, Leuenberger D, Kubli M, Savoini M, Abreu E, Johnson SL, Beaud P, Ingold G, Staub U, Fisher IR, Ernstorfer R, Wolf M, Rettig L. Nonequilibrium charge-density-wave order beyond the thermal limit. Nat Commun 2021; 12:2499. [PMID: 33941788 PMCID: PMC8093280 DOI: 10.1038/s41467-021-22778-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/26/2021] [Indexed: 12/02/2022] Open
Abstract
The interaction of many-body systems with intense light pulses may lead to novel emergent phenomena far from equilibrium. Recent discoveries, such as the optical enhancement of the critical temperature in certain superconductors and the photo-stabilization of hidden phases, have turned this field into an important research frontier. Here, we demonstrate nonthermal charge-density-wave (CDW) order at electronic temperatures far greater than the thermodynamic transition temperature. Using time- and angle-resolved photoemission spectroscopy and time-resolved X-ray diffraction, we investigate the electronic and structural order parameters of an ultrafast photoinduced CDW-to-metal transition. Tracking the dynamical CDW recovery as a function of electronic temperature reveals a behaviour markedly different from equilibrium, which we attribute to the suppression of lattice fluctuations in the transient nonthermal phonon distribution. A complete description of the system's coherent and incoherent order-parameter dynamics is given by a time-dependent Ginzburg-Landau framework, providing access to the transient potential energy surfaces.
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Affiliation(s)
- J Maklar
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany.
| | - Y W Windsor
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - C W Nicholson
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
- Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Fribourg, Switzerland
| | - M Puppin
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
- Laboratory of Ultrafast Spectroscopy, ISIC, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - P Walmsley
- Geballe Laboratory for Advanced Materials and Department of Applied Physics, Stanford University, Stanford, CA, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - V Esposito
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - M Porer
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - J Rittmann
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - D Leuenberger
- Department of Physics, University of Zürich, Zürich, Switzerland
| | - M Kubli
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - M Savoini
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - E Abreu
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - S L Johnson
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - G Ingold
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - U Staub
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - I R Fisher
- Geballe Laboratory for Advanced Materials and Department of Applied Physics, Stanford University, Stanford, CA, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - R Ernstorfer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - M Wolf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - L Rettig
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany.
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Jeng JY, Harasztosi C, Carlton A, Corns L, Marchetta P, Johnson SL, Goodyear RJ, Legan KP, Rüttiger L, Richardson GP, Marcotti W. MET currents and otoacoustic emissions from mice with a detached tectorial membrane indicate the extracellular matrix regulates Ca 2+ near stereocilia. J Physiol 2021; 599:2015-2036. [PMID: 33559882 PMCID: PMC7612128 DOI: 10.1113/jp280905] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 02/03/2021] [Indexed: 10/11/2023] Open
Abstract
KEY POINTS The aim was to determine whether detachment of the tectorial membrane (TM) from the organ of Corti in Tecta/Tectb-/- mice affects the biophysical properties of cochlear outer hair cells (OHCs). Tecta/Tectb-/- mice have highly elevated hearing thresholds, but OHCs mature normally. Mechanoelectrical transducer (MET) channel resting open probability (Po ) in mature OHC is ∼50% in endolymphatic [Ca2+ ], resulting in a large standing depolarizing MET current that would allow OHCs to act optimally as electromotile cochlear amplifiers. MET channel resting Po in vivo is also high in Tecta/Tectb-/- mice, indicating that the TM is unlikely to statically bias the hair bundles of OHCs. Distortion product otoacoustic emissions (DPOAEs), a readout of active, MET-dependent, non-linear cochlear amplification in OHCs, fail to exhibit long-lasting adaptation to repetitive stimulation in Tecta/Tectb-/- mice. We conclude that during prolonged, sound-induced stimulation of the cochlea the TM may determine the extracellular Ca2+ concentration near the OHC's MET channels. ABSTRACT The tectorial membrane (TM) is an acellular structure of the cochlea that is attached to the stereociliary bundles of the outer hair cells (OHCs), electromotile cells that amplify motion of the cochlear partition and sharpen its frequency selectivity. Although the TM is essential for hearing, its role is still not fully understood. In Tecta/Tectb-/- double knockout mice, in which the TM is not coupled to the OHC stereocilia, hearing sensitivity is considerably reduced compared with that of wild-type animals. In vivo, the OHC receptor potentials, assessed using cochlear microphonics, are symmetrical in both wild-type and Tecta/Tectb-/- mice, indicating that the TM does not bias the hair bundle resting position. The functional maturation of hair cells is also unaffected in Tecta/Tectb-/- mice, and the resting open probability of the mechanoelectrical transducer (MET) channel reaches values of ∼50% when the hair bundles of mature OHCs are bathed in an endolymphatic-like Ca2+ concentration (40 μM) in vitro. The resultant large MET current depolarizes OHCs to near -40 mV, a value that would allow optimal activation of the motor protein prestin and normal cochlear amplification. Although the set point of the OHC receptor potential transfer function in vivo may therefore be determined primarily by endolymphatic Ca2+ concentration, repetitive acoustic stimulation fails to produce adaptation of MET-dependent otoacoustic emissions in vivo in the Tecta/Tectb-/- mice. Therefore, the TM is likely to contribute to the regulation of Ca2+ levels around the stereocilia, and thus adaptation of the OHC MET channel during prolonged sound stimulation.
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Affiliation(s)
- Jing-Yi Jeng
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Csaba Harasztosi
- Department of Otolaryngology Head & Neck Surgery, THRC, University of Tübingen, 72076 Tübingen, Germany
| | - Adam Carlton
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Laura Corns
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Philine Marchetta
- Department of Otolaryngology Head & Neck Surgery, THRC, University of Tübingen, 72076 Tübingen, Germany
| | - Stuart L. Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | | | - Kevin P. Legan
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Lukas Rüttiger
- Department of Otolaryngology Head & Neck Surgery, THRC, University of Tübingen, 72076 Tübingen, Germany
| | - Guy P. Richardson
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
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9
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Javelle F, Wiegand M, Joormann J, Timpano KR, Zimmer P, Johnson SL. The German Three Factor Impulsivity Index: Confirmatory factor analysis and ties to demographic and health-related variables. Pers Individ Dif 2021; 171. [PMID: 35185234 DOI: 10.1016/j.paid.2020.110470] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A growing body of research has focused on the differentiation of emotion-related versus non-emotion-related impulsivity, assessed by the Three-Factor Impulsivity (TFI) index. The goal of this study is to develop a German TFI index, and to validate the emotion-related impulsivity subscales against indices of substance abuse, physical or psychological disorder, physical exercise, BMI, and hours of sleep. 395 native-German speakers completed the German TFI index and questions on validity indicators online. Factor analyses supported the three-factor structure, including Pervasive Influence of Feelings, Lack of Follow Through, and Feelings Trigger Action. Correlations between factors were higher than in the original work. Both emotion-related impulsivity subscales correlated significantly with psychological disorder, engagement in and minutes of physical exercise per week. When included in multivariate regression models, the three factors explained 3.1%, and 29.2% of variance in amount of exercise per week and psychological disorder, respectively. In sum, findings indicated that the German TFI index has a robust three-factor structure that showed expected links to validity indicators, and novel effects in relation to physical exercise.
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Affiliation(s)
- F Javelle
- Clinical Exercise-Neuroimmunology Group, Department for Molecular and Cellular Sports Medicine, Institute for Cardiovascular Research and Sports Medicine, German Sport University, Cologne, Germany
| | - M Wiegand
- Department of Psychology, University of Cologne, Germany
| | - J Joormann
- Department of Psychology, Yale University, United States
| | - K R Timpano
- Department of Psychology, University of Miami, United States
| | - P Zimmer
- Clinical Exercise-Neuroimmunology Group, Department for Molecular and Cellular Sports Medicine, Institute for Cardiovascular Research and Sports Medicine, German Sport University, Cologne, Germany.,Department for Performance and Health (Sports Medicine), Institute for Sport and Sport Science, Technical University Dortmund, Dortmund, Germany
| | - S L Johnson
- Department of Psychology, University of California Berkeley, United States
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10
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Jeng JY, Carlton A, Johnson SL, Brown SDM, Holley MC, Bowl MR, Marcotti W. Biophysical and morphological changes in inner hair cells and their efferent innervation in the ageing mouse cochlea. J Physiol 2021; 599:269-287. [PMID: 33179774 PMCID: PMC7612127 DOI: 10.1113/jp280256] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/01/2020] [Indexed: 09/18/2023] Open
Abstract
KEY POINTS Age-related hearing loss is a progressive hearing loss involving environmental and genetic factors, leading to a decrease in hearing sensitivity, threshold and speech discrimination. We compared age-related changes in inner hair cells (IHCs) between four mouse strains with different levels of progressive hearing loss. The surface area of apical coil IHCs (9-12 kHz cochlear region) decreases by about 30-40% with age. The number of BK channels progressively decreases with age in the IHCs from most mouse strains, but the basolateral membrane current profile remains unchanged. The mechanoelectrical transducer current is smaller in mice harbouring the hypomorphic Cdh23 allele Cdh23ahl (C57BL/6J; C57BL/6NTac), but not in Cdh23-repaired mice (C57BL/6NTacCdh23+ ), indicating that it could contribute to the different progression of hearing loss among mouse strains. The degree of efferent rewiring onto aged IHCs, most likely coming from the lateral olivocochlea fibres, was correlated with hearing loss in the different mouse strains. ABSTRACT Inner hair cells (IHCs) are the primary sensory receptors of the mammalian cochlea, transducing acoustic information into electrical signals that are relayed to the afferent neurons. Functional changes in IHCs are a potential cause of age-related hearing loss. Here, we have investigated the functional characteristics of IHCs from early-onset hearing loss mice harbouring the allele Cdh23ahl (C57BL/6J and C57BL/6NTac), from late-onset hearing loss mice (C3H/HeJ), and from mice corrected for the Cdh23ahl mutation (C57BL/6NTacCdh23+ ) with an intermediate hearing phenotype. There was no significant loss of IHCs in the 9-12 kHz cochlear region up to at least 15 months of age, but their surface area decreased progressively by 30-40% starting from ∼6 months of age. Although the size of the BK current decreased with age, IHCs retained a normal KCNQ4 current and resting membrane potential. These basolateral membrane changes were most severe for C57BL/6J and C57BL/6NTac, less so for C57BL/6NTacCdh23+ and minimal or absent in C3H/HeJ mice. We also found that lateral olivocochlear (LOC) efferent fibres re-form functional axon-somatic connections with aged IHCs, but this was seen only sporadically in C3H/HeJ mice. The efferent post-synaptic SK2 channels appear prior to the establishment of the efferent contacts, suggesting that IHCs may play a direct role in re-establishing the LOC-IHC synapses. Finally, we showed that the size of the mechanoelectrical transducer (MET) current from IHCs decreased significantly with age in mice harbouring the Cdh23ahl allele but not in C57BL/6NTacCdh23+ mice, indicating that the MET apparatus directly contributes to the progression of age-related hearing loss.
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Affiliation(s)
- Jing-Yi Jeng
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Adam Carlton
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Stuart L. Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Steve D. M. Brown
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, OX11 0RD, UK
| | - Matthew C. Holley
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Michael R. Bowl
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, OX11 0RD, UK
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
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11
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Jeng JY, Johnson SL, Carlton AJ, DeTomasi L, Goodyear R, DeFaveri F, Furness DN, Wells S, Brown SDM, Holley MC, Richardson GP, Mustapha M, Bowl MR, Marcotti W. Age-related changes in the biophysical and morphological characteristics of mouse cochlear outer hair cells. J Physiol 2020; 598:3891-3910. [PMID: 32608086 PMCID: PMC7612122 DOI: 10.1113/jp279795] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 06/25/2020] [Indexed: 09/01/2023] Open
Abstract
KEY POINTS Age-related hearing loss (ARHL) is a very heterogeneous disease, resulting from cellular senescence, genetic predisposition and environmental factors (e.g. noise exposure). Currently, we know very little about age-related changes occurring in the auditory sensory cells, including those associated with the outer hair cells (OHCs). Using different mouse strains, we show that OHCs undergo several morphological and biophysical changes in the ageing cochlea. Ageing OHCs also exhibited the progressive loss of afferent and efferent synapses. We also provide evidence that the size of the mechanoelectrical transducer current is reduced in ageing OHCs, highlighting its possible contribution in cochlear ageing. ABSTRACT Outer hair cells (OHCs) are electromotile sensory receptors that provide sound amplification within the mammalian cochlea. Although OHCs appear susceptible to ageing, the progression of the pathophysiological changes in these cells is still poorly understood. By using mouse strains with a different progression of hearing loss (C57BL/6J, C57BL/6NTac, C57BL/6NTacCdh23+ , C3H/HeJ), we have identified morphological, physiological and molecular changes in ageing OHCs (9-12 kHz cochlear region). We show that by 6 months of age, OHCs from all strains underwent a reduction in surface area, which was not a sign of degeneration. Although the ageing OHCs retained a normal basolateral membrane protein profile, they showed a reduction in the size of the K+ current and non-linear capacitance, a readout of prestin-dependent electromotility. Despite these changes, OHCs have a normal Vm and retain the ability to amplify sound, as distortion product otoacoustic emission thresholds were not affected in aged, good-hearing mice (C3H/HeJ, C57BL/6NTacCdh23+ ). The loss of afferent synapses was present in all strains at 15 months. The number of efferent synapses per OHCs, defined as postsynaptic SK2 puncta, was reduced in aged OHCs of all strains apart from C3H mice. Several of the identified changes occurred in aged OHCs from all mouse strains, thus representing a general trait in the pathophysiological progression of age-related hearing loss, possibly aimed at preserving functionality. We have also shown that the mechanoelectrical transduction (MET) current from OHCs of mice harbouring the Cdh23ahl allele is reduced with age, highlighting the possibility that changes in the MET apparatus could play a role in cochlear ageing.
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Affiliation(s)
- Jing-Yi Jeng
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Stuart L. Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Adam J Carlton
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Lara DeTomasi
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Richard Goodyear
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Francesca DeFaveri
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | | | - Sara Wells
- Mary Lyon Centre, MRC Harwell Institute, Oxfordshire, UK
| | | | - Matthew C. Holley
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Guy P. Richardson
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Mirna Mustapha
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Michael R. Bowl
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, UK
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
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12
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Jeng JY, Ceriani F, Olt J, Brown SDM, Holley MC, Bowl MR, Johnson SL, Marcotti W. Pathophysiological changes in inner hair cell ribbon synapses in the ageing mammalian cochlea. J Physiol 2020; 598:4339-4355. [PMID: 32710572 DOI: 10.1113/jp280018] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/24/2020] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Age-related hearing loss (ARHL) is associated with the loss of inner hair cell (IHC) ribbon synapses, lower hearing sensitivity and decreased ability to understand speech, especially in a noisy environment. Little is known about the age-related physiological and morphological changes that occur at ribbon synapses. We show that the differing degrees of ARHL in four selected mouse stains is correlated with the loss of ribbon synapses, being most severe for the strains C57BL/6NTac and C57BL/6J, less so for C57BL/6NTacCdh23+ -Repaired and lowest for C3H/HeJ. Despite the loss of ribbon synapses with age, the volume of the remaining ribbons increased and the size and kinetics of Ca2+ -dependent exocytosis in IHCs was unaffected, indicating the presence of a previously unknown degree of functional compensation at ribbon synapses. Although the age-related morphological changes at IHC ribbon synapses contribute to the different progression of ARHL, without the observed functional compensation hearing loss could be greater. ABSTRACT Mammalian cochlear inner hair cells (IHCs) are specialized sensory receptors able to provide dynamic coding of sound signals. This ability is largely conferred by their ribbon synapses, which tether a large number of vesicles at the IHC's presynaptic active zones, allowing high rates of sustained synaptic transmission onto the afferent fibres. How the physiological and morphological properties of ribbon synapses change with age remains largely unknown. Here, we have investigated the biophysical and morphological properties of IHC ribbon synapses in the ageing cochlea (9-12 kHz region) of four mouse strains commonly used in hearing research: early-onset progressive hearing loss (C57BL/6J and C57BL/6NTac) and 'good hearing' strains (C57BL/6NTacCdh23+ and C3H/HeJ). We found that with age, both modiolar and pillar sides of the IHC exhibited a loss of ribbons, but there was an increased volume of those that remained. These morphological changes, which only occurred after 6 months of age, were correlated with the level of hearing loss in the different mouse strains, being most severe for C57BL/6NTac and C57BL/6J, less so for C57BL/6NTacCdh23+ and absent for C3H/HeJ strains. Despite the age-related reduction in ribbon number in three of the four strains, the size and kinetics of Ca2+ -dependent exocytosis, as well as the replenishment of synaptic vesicles, in IHCs was not affected. The degree of vesicle release at the fewer, but larger, individual remaining ribbon synapses colocalized with the post-synaptic afferent terminals is likely to increase, indicating the presence of a previously unknown degree of functional compensation in the ageing mouse cochlea.
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Affiliation(s)
- Jing-Yi Jeng
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK.,Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Federico Ceriani
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK.,Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Jennifer Olt
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Steve D M Brown
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, UK
| | - Matthew C Holley
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Michael R Bowl
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, UK
| | - Stuart L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK.,Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK.,Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
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13
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Spaiardi P, Marcotti W, Masetto S, Johnson SL. Exocytosis in mouse vestibular Type II hair cells shows a high-order Ca 2+ dependence that is independent of synaptotagmin-4. Physiol Rep 2020; 8:e14509. [PMID: 32691536 PMCID: PMC7371649 DOI: 10.14814/phy2.14509] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/21/2020] [Accepted: 06/22/2020] [Indexed: 11/24/2022] Open
Abstract
Mature hair cells transduce information over a wide range of stimulus intensities and frequencies for prolonged periods of time. The efficiency of such a demanding task is reflected in the characteristics of exocytosis at their specialized presynaptic ribbons. Ribbons are electron-dense structures able to tether a large number of releasable vesicles allowing them to maintain high rates of vesicle release. Calcium entry through rapidly activating, non-inactivating CaV 1.3 (L-type) Ca2+ channels in response to cell depolarization causes a local increase in Ca2+ at the ribbon synapses, which is detected by the exocytotic Ca2+ sensors. The Ca2+ dependence of vesicle exocytosis at mammalian vestibular hair cell (VHC) ribbon synapses is believed to be linear, similar to that observed in mature cochlear inner hair cells (IHCs). The linear relation has been shown to correlate with the presence of the Ca2+ sensor synaptotagmin-4 (Syt-4). Therefore, we studied the exocytotic Ca2+ dependence, and the release kinetics of different vesicle pool populations, in Type II VHCs of control and Syt-4 knockout mice using patch-clamp capacitance measurements, under physiological recording conditions. We found that exocytosis in mature control and knockout Type II VHCs displayed a high-order dependence on Ca2+ entry, rather than the linear relation previously observed. Consistent with this finding, the Ca2+ dependence and release kinetics of the ready releasable pool (RRP) of vesicles were not affected by an absence of Syt-4. However, we did find that Syt-4 could play a role in regulating the release of the secondary releasable pool (SRP) in these cells. Our findings show that the coupling between Ca2+ influx and neurotransmitter release at mature Type II VHC ribbon synapses is faithfully described by a nonlinear relation that is likely to be more appropriate for the accurate encoding of low-frequency vestibular information, consistent with that observed at low-frequency mammalian auditory receptors.
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Affiliation(s)
- Paolo Spaiardi
- Department of Brain and Behavioral SciencesUniversity of PaviaPaviaItaly
| | - Walter Marcotti
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | - Sergio Masetto
- Department of Brain and Behavioral SciencesUniversity of PaviaPaviaItaly
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14
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Spaiardi P, Tavazzani E, Manca M, Russo G, Prigioni I, Biella G, Giunta R, Johnson SL, Marcotti W, Masetto S. K + Accumulation and Clearance in the Calyx Synaptic Cleft of Type I Mouse Vestibular Hair Cells. Neuroscience 2020; 426:69-86. [PMID: 31846752 PMCID: PMC6985899 DOI: 10.1016/j.neuroscience.2019.11.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 11/07/2019] [Accepted: 11/16/2019] [Indexed: 11/29/2022]
Abstract
Vestibular organs of Amniotes contain two types of sensory cells, named Type I and Type II hair cells. While Type II hair cells are contacted by several small bouton nerve terminals, Type I hair cells receive a giant terminal, called a calyx, which encloses their basolateral membrane almost completely. Both hair cell types release glutamate, which depolarizes the afferent terminal by binding to AMPA post-synaptic receptors. However, there is evidence that non-vesicular signal transmission also occurs at the Type I hair cell-calyx synapse, possibly involving direct depolarization of the calyx by K+ exiting the hair cell. To better investigate this aspect, we performed whole-cell patch-clamp recordings from mouse Type I hair cells or their associated calyx. We found that [K+] in the calyceal synaptic cleft is elevated at rest relative to the interstitial (extracellular) solution and can increase or decrease during hair cell depolarization or repolarization, respectively. The change in [K+] was primarily driven by GK,L, the low-voltage-activated, non-inactivating K+ conductance specifically expressed by Type I hair cells. Simple diffusion of K+ between the cleft and the extracellular compartment appeared substantially restricted by the calyx inner membrane, with the ion channels and active transporters playing a crucial role in regulating intercellular [K+]. Calyx recordings were consistent with K+ leaving the synaptic cleft through postsynaptic voltage-gated K+ channels involving KV1 and KV7 subunits. The above scenario is consistent with direct depolarization and hyperpolarization of the calyx membrane potential by intercellular K+.
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Affiliation(s)
- P Spaiardi
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - E Tavazzani
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - M Manca
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - G Russo
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - I Prigioni
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - G Biella
- Department of Biology and Biotechnology, University of Pavia, Pavia 27100, Italy
| | - R Giunta
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy
| | - S L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - W Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - S Masetto
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia 27100, Italy.
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15
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Jeng JY, Ceriani F, Hendry A, Johnson SL, Yen P, Simmons DD, Kros CJ, Marcotti W. Hair cell maturation is differentially regulated along the tonotopic axis of the mammalian cochlea. J Physiol 2019; 598:151-170. [PMID: 31661723 PMCID: PMC6972525 DOI: 10.1113/jp279012] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 10/24/2019] [Indexed: 12/15/2022] Open
Abstract
Key points Outer hair cells (OHCs) enhance the sensitivity and the frequency tuning of the mammalian cochlea. Similar to the primary sensory receptor, the inner hair cells (IHCs), the mature functional characteristics of OHCs are acquired before hearing onset. We found that OHCs, like IHCs, fire spontaneous Ca2+‐induced action potentials (APs) during immature stages of development, which are driven by CaV1.3 Ca2+ channels. We also showed that the development of low‐ and high‐frequency hair cells is differentially regulated during pre‐hearing stages, with the former cells being more strongly dependent on experience‐independent Ca2+ action potential activity.
Abstract Sound amplification within the mammalian cochlea depends upon specialized hair cells, the outer hair cells (OHCs), which possess both sensory and motile capabilities. In various altricial rodents, OHCs become functionally competent from around postnatal day 7 (P7), before the primary sensory inner hair cells (IHCs), which become competent at about the onset of hearing (P12). The mechanisms responsible for the maturation of OHCs and their synaptic specialization remain poorly understood. We report that spontaneous Ca2+ activity in the immature cochlea, which is generated by CaV1.3 Ca2+ channels, differentially regulates the maturation of hair cells along the cochlea. Under near‐physiological recording conditions we found that, similar to IHCs, immature OHCs elicited spontaneous Ca2+ action potentials (APs), but only during the first few postnatal days. Genetic ablation of these APs in vivo, using CaV1.3−/− mice, prevented the normal developmental acquisition of mature‐like basolateral membrane currents in low‐frequency (apical) hair cells, such as IK,n (carried by KCNQ4 channels), ISK2 and IACh (α9α10nAChRs) in OHCs and IK,n and IK,f (BK channels) in IHCs. Electromotility and prestin expression in OHCs were normal in CaV1.3−/− mice. The maturation of high‐frequency (basal) hair cells was also affected in CaV1.3−/− mice, but to a much lesser extent than apical cells. However, a characteristic feature in CaV1.3−/− mice was the reduced hair cell size irrespective of their cochlear location. We conclude that the development of low‐ and high‐frequency hair cells is differentially regulated during development, with apical cells being more strongly dependent on experience‐independent Ca2+ APs. Outer hair cells (OHCs) enhance the sensitivity and the frequency tuning of the mammalian cochlea. Similar to the primary sensory receptor, the inner hair cells (IHCs), the mature functional characteristics of OHCs are acquired before hearing onset. We found that OHCs, like IHCs, fire spontaneous Ca2+‐induced action potentials (APs) during immature stages of development, which are driven by CaV1.3 Ca2+ channels. We also showed that the development of low‐ and high‐frequency hair cells is differentially regulated during pre‐hearing stages, with the former cells being more strongly dependent on experience‐independent Ca2+ action potential activity.
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Affiliation(s)
- Jing-Yi Jeng
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Federico Ceriani
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Aenea Hendry
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Stuart L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Piece Yen
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | | | - Corné J Kros
- School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
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16
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Abstract
To provide a meaningful representation of the auditory landscape, mammalian cochlear hair cells are optimized to detect sounds over an incredibly broad range of frequencies and intensities with unparalleled accuracy. This ability is largely conferred by specialized ribbon synapses that continuously transmit acoustic information with high fidelity and sub-millisecond precision to the afferent dendrites of the spiral ganglion neurons. To achieve this extraordinary task, ribbon synapses employ a unique combination of molecules and mechanisms that are tailored to sounds of different frequencies. Here we review the current understanding of how the hair cell's presynaptic machinery and its postsynaptic afferent connections are formed, how they mature, and how their function is adapted for an accurate perception of sound.
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Affiliation(s)
- Stuart L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Saaid Safieddine
- UMRS 1120, Institut Pasteur, Paris, France
- Sorbonne Universités, UPMC Université Paris 06, Complexité du Vivant, Paris, France
| | - Mirna Mustapha
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, United Kingdom
- Department of Otolaryngology-Head & Neck Surgery, Stanford University, Stanford, California 94035
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, United Kingdom
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17
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Bardhan T, Jeng J, Waldmann M, Ceriani F, Johnson SL, Olt J, Rüttiger L, Marcotti W, Holley MC. Gata3 is required for the functional maturation of inner hair cells and their innervation in the mouse cochlea. J Physiol 2019; 597:3389-3406. [PMID: 31069810 PMCID: PMC6636704 DOI: 10.1113/jp277997] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 05/07/2019] [Indexed: 01/14/2023] Open
Abstract
KEY POINTS The physiological maturation of auditory hair cells and their innervation requires precise temporal and spatial control of cell differentiation. The transcription factor gata3 is essential for the earliest stages of auditory system development and for survival and synaptogenesis in auditory sensory afferent neurons. We show that during postnatal development in the mouse inner ear gata3 is required for the biophysical maturation, growth and innervation of inner hair cells; in contrast, it is required only for the survival of outer hair cells. Loss of gata3 in inner hair cells causes progressive hearing loss and accounts for at least some of the deafness associated with the human hypoparathyroidism, deafness and renal anomaly (HDR) syndrome. The results show that gata3 is critical for later stages of mammalian auditory system development where it plays distinct, complementary roles in the coordinated maturation of sensory hair cells and their innervation. ABSTRACT The zinc finger transcription factor gata3 regulates inner ear development from the formation of the embryonic otic placode. Throughout development, gata3 is expressed dynamically in all the major cochlear cell types. Its role in afferent formation is well established but its possible involvement in hair cell maturation remains unknown. Here, we find that in heterozygous gata3 null mice (gata3+/- ) outer hair cells (OHCs) differentiate normally but their numbers are significantly lower. In contrast, inner hair cells (IHCs) survive normally but they fail to acquire adult basolateral membrane currents, retain pre-hearing current and efferent innervation profiles and have fewer ribbon synapses. Targeted deletion of gata3 driven by otoferlin-cre recombinase (gata3fl/fl otof-cre+/- ) in IHCs does not affect OHCs or the number of IHC afferent synapses but it leads to a failure in IHC maturation comparable to that observed in gata3+/- mice. Auditory brainstem responses in gata3fl/fl otof-cre+/- mice reveal progressive hearing loss that becomes profound by 6-7 months, whilst distortion product otoacoustic emissions are no different to control animals up to this age. Our results, alongside existing data, indicate that gata3 has specific, complementary functions in different cell types during inner ear development and that its continued expression in the sensory epithelium orchestrates critical aspects of physiological development and neural connectivity. Furthermore, our work indicates that hearing loss in human hypoparathyroidism, deafness and renal anomaly (HDR) syndrome arises from functional deficits in IHCs as well as loss of function from OHCs and both afferent and efferent neurons.
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MESH Headings
- Animals
- Cell Differentiation/physiology
- Cochlea/metabolism
- Cochlea/physiology
- GATA3 Transcription Factor/metabolism
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Inner/physiology
- Hair Cells, Auditory, Outer/metabolism
- Hair Cells, Auditory, Outer/physiology
- Hair Cells, Vestibular/metabolism
- Hair Cells, Vestibular/physiology
- Hearing/physiology
- Hearing Loss/metabolism
- Hearing Loss/physiopathology
- Membrane Proteins/metabolism
- Mice, Knockout
- Mice, Transgenic
- Sensory Receptor Cells/metabolism
- Sensory Receptor Cells/physiology
- Synapses/metabolism
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Affiliation(s)
- Tanaya Bardhan
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | - Jing‐Yi Jeng
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | - Marco Waldmann
- Department of OtolaryngologyTübingen Hearing Research CenterSection of Physiological Acoustics and CommunicationUniversity of Tübingen72076TübingenGermany
| | - Federico Ceriani
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | | | - Jennifer Olt
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | - Lukas Rüttiger
- Department of OtolaryngologyTübingen Hearing Research CenterSection of Physiological Acoustics and CommunicationUniversity of Tübingen72076TübingenGermany
| | - Walter Marcotti
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
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18
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Houver S, Huber L, Savoini M, Abreu E, Johnson SL. 2D THz spectroscopic investigation of ballistic conduction-band electron dynamics in InSb. Opt Express 2019; 27:10854-10865. [PMID: 31052939 DOI: 10.1364/oe.27.010854] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
Using reflective cross-polarized 2D THz time-domain spectroscopy in the range of 1-12 THz, we follow the trajectory of the out-of-equilibrium electron population in the low-bandgap semiconductor InSb. The 2D THz spectra show a set of distinct features at combinations of the plasma-edge and vibration frequencies. Using finite difference time domain simulations combined with a tight binding model of the band structure, we assign these features to electronic nonlinearities and show that the nonlinear response in the first picoseconds is dominated by coherent ballistic motion of the electrons. We demonstrate that this technique can be used to investigate the landscape of the band curvature near the Γ-point, as illustrated by the observation of anisotropy in the (100)-plane.
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19
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Ceriani F, Hendry A, Jeng JY, Johnson SL, Stephani F, Olt J, Holley MC, Mammano F, Engel J, Kros CJ, Simmons DD, Marcotti W. Coordinated calcium signalling in cochlear sensory and non-sensory cells refines afferent innervation of outer hair cells. EMBO J 2019; 38:embj.201899839. [PMID: 30804003 PMCID: PMC6484507 DOI: 10.15252/embj.201899839] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 12/11/2018] [Accepted: 01/18/2019] [Indexed: 12/12/2022] Open
Abstract
Outer hair cells (OHCs) are highly specialized sensory cells conferring the fine‐tuning and high sensitivity of the mammalian cochlea to acoustic stimuli. Here, by genetically manipulating spontaneous Ca2+ signalling in mice in vivo, through a period of early postnatal development, we find that the refinement of OHC afferent innervation is regulated by complementary spontaneous Ca2+ signals originating in OHCs and non‐sensory cells. OHCs fire spontaneous Ca2+ action potentials during a narrow period of neonatal development. Simultaneously, waves of Ca2+ activity in the non‐sensory cells of the greater epithelial ridge cause, via ATP‐induced activation of P2X3 receptors, the increase and synchronization of the Ca2+ activity in nearby OHCs. This synchronization is required for the refinement of their immature afferent innervation. In the absence of connexin channels, Ca2+ waves are impaired, leading to a reduction in the number of ribbon synapses and afferent fibres on OHCs. We propose that the correct maturation of the afferent connectivity of OHCs requires experience‐independent Ca2+ signals from sensory and non‐sensory cells.
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Affiliation(s)
- Federico Ceriani
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Aenea Hendry
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Jing-Yi Jeng
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Stuart L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Friederike Stephani
- Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Jennifer Olt
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Matthew C Holley
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Fabio Mammano
- Department of Physics and Astronomy "G. Galilei", University of Padua, Padova, Italy.,Department of Biomedical Sciences, Institute of Cell Biology and Neurobiology, Italian National Research Council, Monterotondo, Italy
| | - Jutta Engel
- Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Corné J Kros
- School of Life Sciences, University of Sussex, Brighton, UK
| | | | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
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20
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Abstract
We present a spectroscopic method for measuring the fluorescence quantum efficiency [Formula: see text] of fluorophores that does not require calibration standards. Photothermal Deflection Spectroscopy (PDS) is combined with conventional absorbance spectroscopy, and [Formula: see text] is extracted from fits over the spectral range of interest. This technique obviates the need for multiple measurements-either on calibration standards or as a function of concentration-and yields results of [Formula: see text] in a single measurement consistent with previously reported values. Five different organic dyes are tested whose absorbance/fluorescence profiles span the visible spectrum and whose known quantum efficiencies range from 0 to near 1. The accuracy of the results over significant ranges of wavelength and quantum yield demonstrate the robustness and efficacy of this method.
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Affiliation(s)
- B Couch
- Department of Physics, Transylvania University, Lexington KY, United States of America
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21
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Frith TJ, Granata I, Wind M, Stout E, Thompson O, Neumann K, Stavish D, Heath PR, Ortmann D, Hackland JO, Anastassiadis K, Gouti M, Briscoe J, Wilson V, Johnson SL, Placzek M, Guarracino MR, Andrews PW, Tsakiridis A. Human axial progenitors generate trunk neural crest cells in vitro. eLife 2018; 7:35786. [PMID: 30095409 PMCID: PMC6101942 DOI: 10.7554/elife.35786] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 08/09/2018] [Indexed: 12/11/2022] Open
Abstract
The neural crest (NC) is a multipotent embryonic cell population that generates distinct cell types in an axial position-dependent manner. The production of NC cells from human pluripotent stem cells (hPSCs) is a valuable approach to study human NC biology. However, the origin of human trunk NC remains undefined and current in vitro differentiation strategies induce only a modest yield of trunk NC cells. Here we show that hPSC-derived axial progenitors, the posteriorly-located drivers of embryonic axis elongation, give rise to trunk NC cells and their derivatives. Moreover, we define the molecular signatures associated with the emergence of human NC cells of distinct axial identities in vitro. Collectively, our findings indicate that there are two routes toward a human post-cranial NC state: the birth of cardiac and vagal NC is facilitated by retinoic acid-induced posteriorisation of an anterior precursor whereas trunk NC arises within a pool of posterior axial progenitors.
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Affiliation(s)
- Thomas Jr Frith
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield, United Kingdom
| | - Ilaria Granata
- Computational and Data Science Laboratory, High Performance Computing and Networking Institute, National Research Council of Italy, Napoli, Italy
| | - Matthew Wind
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield, United Kingdom
| | - Erin Stout
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield, United Kingdom
| | - Oliver Thompson
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield, United Kingdom
| | - Katrin Neumann
- Stem Cell Engineering, Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Dylan Stavish
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield, United Kingdom
| | - Paul R Heath
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Daniel Ortmann
- Anne McLaren Laboratory, Wellcome Trust-MRC Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | - James Os Hackland
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield, United Kingdom
| | | | - Mina Gouti
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | | | - Valerie Wilson
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Stuart L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Marysia Placzek
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom.,The Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| | - Mario R Guarracino
- Computational and Data Science Laboratory, High Performance Computing and Networking Institute, National Research Council of Italy, Napoli, Italy
| | - Peter W Andrews
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield, United Kingdom
| | - Anestis Tsakiridis
- Centre for Stem Cell Biology, Department of Biomedical Science, The University of Sheffield, Sheffield, United Kingdom.,The Bateson Centre, University of Sheffield, Sheffield, United Kingdom
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22
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Porer M, Fechner M, Bothschafter EM, Rettig L, Savoini M, Esposito V, Rittmann J, Kubli M, Neugebauer MJ, Abreu E, Kubacka T, Huber T, Lantz G, Parchenko S, Grübel S, Paarmann A, Noack J, Beaud P, Ingold G, Aschauer U, Johnson SL, Staub U. Ultrafast Relaxation Dynamics of the Antiferrodistortive Phase in Ca Doped SrTiO_{3}. Phys Rev Lett 2018; 121:055701. [PMID: 30118273 DOI: 10.1103/physrevlett.121.055701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Indexed: 06/08/2023]
Abstract
The ultrafast dynamics of the octahedral rotation in Ca:SrTiO_{3} is studied by time-resolved x-ray diffraction after photoexcitation over the band gap. By monitoring the diffraction intensity of a superlattice reflection that is directly related to the structural order parameter of the soft-mode driven antiferrodistortive phase in Ca:SrTiO_{3}, we observe an ultrafast relaxation on a 0.2 ps timescale of the rotation of the oxygen octahedron, which is found to be independent of the initial temperature despite large changes in the corresponding soft-mode frequency. A further, much smaller reduction on a slower picosecond timescale is attributed to thermal effects. Time-dependent density-functional-theory calculations show that the fast response can be ascribed to an ultrafast displacive modification of the soft-mode potential towards the normal state induced by holes created in the oxygen 2p states.
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Affiliation(s)
- M Porer
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - M Fechner
- Max Planck Institute for the Structure and Dynamics of Matter, CFEL, 22761 Hamburg, Germany
- Materials Theory, ETH Zürich, 8093 Zürich, Switzerland
| | - E M Bothschafter
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - L Rettig
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - M Savoini
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - V Esposito
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - J Rittmann
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - M Kubli
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - M J Neugebauer
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - E Abreu
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - T Kubacka
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - T Huber
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - G Lantz
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - S Parchenko
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - S Grübel
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - A Paarmann
- Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - J Noack
- Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - G Ingold
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - U Aschauer
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - S L Johnson
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - U Staub
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
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23
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Lantz G, Neugebauer MJ, Kubli M, Savoini M, Abreu E, Tasca K, Dornes C, Esposito V, Rittmann J, Windsor YW, Beaud P, Ingold G, Johnson SL. Coupling between a Charge Density Wave and Magnetism in an Heusler Material. Phys Rev Lett 2017; 119:227207. [PMID: 29286787 DOI: 10.1103/physrevlett.119.227207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Indexed: 06/07/2023]
Abstract
The prototypical magnetic memory shape alloy Ni_{2}MnGa undergoes various phase transitions as a function of the temperature, pressure, and doping. In the low-temperature phases below 260 K, an incommensurate structural modulation occurs along the [110] direction which is thought to arise from the softening of a phonon mode. It is not at present clear how this phenomenon is related, if at all, to the magnetic memory effect. Here we report time-resolved measurements which track both the structural and magnetic components of the phase transition from the modulated cubic phase as it is brought into the high-symmetry phase. The results suggest that the photoinduced demagnetization modifies the Fermi surface in regions that couple strongly to the periodicity of the structural modulation through the nesting vector. The amplitude of the periodic lattice distortion, however, appears to be less affected by the demagnetization.
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Affiliation(s)
- G Lantz
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - M J Neugebauer
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - M Kubli
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - M Savoini
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - E Abreu
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - K Tasca
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - C Dornes
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - V Esposito
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J Rittmann
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Y W Windsor
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - G Ingold
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - S L Johnson
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
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24
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Johnson SL, Savoini M, Beaud P, Ingold G, Staub U, Carbone F, Castiglioni L, Hengsberger M, Osterwalder J. Watching ultrafast responses of structure and magnetism in condensed matter with momentum-resolved probes. Struct Dyn 2017; 4:061506. [PMID: 29308418 PMCID: PMC5741437 DOI: 10.1063/1.4996176] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/21/2017] [Indexed: 05/26/2023]
Abstract
We present a non-comprehensive review of some representative experimental studies in crystalline condensed matter systems where the effects of intense ultrashort light pulses are probed using x-ray diffraction and photoelectron spectroscopy. On an ultrafast (sub-picosecond) time scale, conventional concepts derived from the assumption of thermodynamic equilibrium must often be modified in order to adequately describe the time-dependent changes in material properties. There are several commonly adopted approaches to this modification, appropriate in different experimental circumstances. One approach is to treat the material as a collection of quasi-thermal subsystems in thermal contact with each other in the so-called "N-temperature" models. On the other extreme, one can also treat the time-dependent changes as fully coherent dynamics of a sometimes complex network of excitations. Here, we present examples of experiments that fall into each of these categories, as well as experiments that partake of both models. We conclude with a discussion of the limitations and future potential of these concepts.
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Affiliation(s)
- S L Johnson
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zürich, CH-8093 Zurich, Switzerland
| | - M Savoini
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zürich, CH-8093 Zurich, Switzerland
| | - P Beaud
- Paul Scherrer Institut, CH-5032 Villigen, Switzerland
| | - G Ingold
- Paul Scherrer Institut, CH-5032 Villigen, Switzerland
| | - U Staub
- Paul Scherrer Institut, CH-5032 Villigen, Switzerland
| | - F Carbone
- Laboratory for Ultrafast Microscopy and Electron Scattering, ICMP, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - L Castiglioni
- Department of Physics, University of Zurich, CH-8057 Zurich, Switzerland
| | - M Hengsberger
- Department of Physics, University of Zurich, CH-8057 Zurich, Switzerland
| | - J Osterwalder
- Department of Physics, University of Zurich, CH-8057 Zurich, Switzerland
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25
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Laulhé C, Huber T, Lantz G, Ferrer A, Mariager SO, Grübel S, Rittmann J, Johnson JA, Esposito V, Lübcke A, Huber L, Kubli M, Savoini M, Jacques VLR, Cario L, Corraze B, Janod E, Ingold G, Beaud P, Johnson SL, Ravy S. Ultrafast Formation of a Charge Density Wave State in 1T-TaS_{2}: Observation at Nanometer Scales Using Time-Resolved X-Ray Diffraction. Phys Rev Lett 2017; 118:247401. [PMID: 28665649 DOI: 10.1103/physrevlett.118.247401] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Indexed: 05/19/2023]
Abstract
Femtosecond time-resolved x-ray diffraction is used to study a photoinduced phase transition between two charge density wave (CDW) states in 1T-TaS_{2}, namely the nearly commensurate (NC) and the incommensurate (I) CDW states. Structural modulations associated with the NC-CDW order are found to disappear within 400 fs. The photoinduced I-CDW phase then develops through a nucleation and growth process which ends 100 ps after laser excitation. We demonstrate that the newly formed I-CDW phase is fragmented into several nanometric domains that are growing through a coarsening process. The coarsening dynamics is found to follow the universal Lifshitz-Allen-Cahn growth law, which describes the ordering kinetics in systems exhibiting a nonconservative order parameter.
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Affiliation(s)
- C Laulhé
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin-BP 48, F-91192 Gif-sur-Yvette, France
- Université Paris-Saclay (Université Paris-Sud), F-91405 Orsay Cedex, France
| | - T Huber
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - G Lantz
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS, UMR 8502, F-91405 Orsay, France
| | - A Ferrer
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - S O Mariager
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - S Grübel
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - J Rittmann
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - J A Johnson
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - V Esposito
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - A Lübcke
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - L Huber
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - M Kubli
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - M Savoini
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - V L R Jacques
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS, UMR 8502, F-91405 Orsay, France
| | - L Cario
- Institut des Matériaux Jean Rouxel-UMR 6502, Université de Nantes, 2 rue de la Houssinière, F-44322 Nantes, France
| | - B Corraze
- Institut des Matériaux Jean Rouxel-UMR 6502, Université de Nantes, 2 rue de la Houssinière, F-44322 Nantes, France
| | - E Janod
- Institut des Matériaux Jean Rouxel-UMR 6502, Université de Nantes, 2 rue de la Houssinière, F-44322 Nantes, France
| | - G Ingold
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - S L Johnson
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - S Ravy
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS, UMR 8502, F-91405 Orsay, France
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26
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Nunez DJ, Yao X, Lin J, Walker A, Zuo P, Webster L, Krug-Gourley S, Zamek-Gliszczynski MJ, Gillmor DS, Johnson SL. Glucose and lipid effects of the ileal apical sodium-dependent bile acid transporter inhibitor GSK2330672: double-blind randomized trials with type 2 diabetes subjects taking metformin. Diabetes Obes Metab 2016; 18:654-62. [PMID: 26939572 DOI: 10.1111/dom.12656] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 01/10/2016] [Accepted: 02/27/2016] [Indexed: 12/15/2022]
Abstract
AIMS To investigate the pharmacodynamics, pharmacokinetics and safety/tolerability of blocking reuptake of bile acids using the inhibitor GSK2330672 (GSK672) in patients with type 2 diabetes (T2D). METHODS Subjects with T2D taking metformin were enrolled in two studies in which they took metformin 850 mg twice daily for 2 weeks prior to and during the randomized treatment periods. In the first crossover study (n = 15), subjects received GSK672 45 mg, escalating to 90 mg, twice daily, or placebo for 7 days. The second parallel-group study (n = 75) investigated GSK672 10-90 mg twice daily, placebo or sitagliptin for 14 days. RESULTS In both studies, GSK672 reduced circulating bile acids and increased serum 7-α-hydroxy-4-cholesten-3-one (C4), an intermediate in the hepatic synthesis of bile acids. Compared with placebo, in the parallel-group study 90 mg GSK672 twice daily reduced fasting plasma glucose [FPG; -1.21 mmol/l; 95% confidence interval (CI) -2.14, -0.28] and weighted-mean glucose area under the curve (AUC)0-24 h (-1.33 mmol/l; 95% CI -2.30, -0.36), as well as fasting and weighted-mean insulin AUC0 -24 h . GSK672 also reduced cholesterol (LDL, non-HDL and total cholesterol) and apolipoprotein B concentrations; the maximum LDL cholesterol reduction was ∼40%. There was no change in HDL cholesterol but there was a trend towards increased fasting triglyceride levels in the GSK672 groups compared with placebo. In both studies, the most common adverse events associated with GSK672 were gastrointestinal, mostly diarrhoea (22-100%), which appeared to be independent of dose. CONCLUSIONS In subjects with T2D on metformin, GSK672 improved glucose and lipids, but there was a high incidence of gastrointestinal adverse events.
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Affiliation(s)
- D J Nunez
- GlaxoSmithKline plc, Research Triangle Park, NC and Collegeville, PA, USA
| | - X Yao
- Alexion Pharmaceuticals, Inc., Cambridge, MA, USA
| | - J Lin
- Grifols Therapeutics Inc., Research Triangle Park, NC, USA
| | - A Walker
- GlaxoSmithKline plc, Research Triangle Park, NC and Collegeville, PA, USA
| | - P Zuo
- Parexel International, Durham, NC, USA
| | | | - S Krug-Gourley
- GlaxoSmithKline plc, Research Triangle Park, NC and Collegeville, PA, USA
| | | | - D S Gillmor
- Pharmaceutical Product Development LLC, Morrisville, NC, USA
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27
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Rettig L, Dornes C, Thielemann-Kühn N, Pontius N, Zabel H, Schlagel DL, Lograsso TA, Chollet M, Robert A, Sikorski M, Song S, Glownia JM, Schüßler-Langeheine C, Johnson SL, Staub U. Itinerant and Localized Magnetization Dynamics in Antiferromagnetic Ho. Phys Rev Lett 2016; 116:257202. [PMID: 27391747 DOI: 10.1103/physrevlett.116.257202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Indexed: 05/19/2023]
Abstract
Using femtosecond time-resolved resonant magnetic x-ray diffraction at the Ho L_{3} absorption edge, we investigate the demagnetization dynamics in antiferromagnetically ordered metallic Ho after femtosecond optical excitation. Tuning the x-ray energy to the electric dipole (E1, 2p→5d) or quadrupole (E2, 2p→4f) transition allows us to selectively and independently study the spin dynamics of the itinerant 5d and localized 4f electronic subsystems via the suppression of the magnetic (2 1 3-τ) satellite peak. We find demagnetization time scales very similar to ferromagnetic 4f systems, suggesting that the loss of magnetic order occurs via a similar spin-flip process in both cases. The simultaneous demagnetization of both subsystems demonstrates strong intra-atomic 4f-5d exchange coupling. In addition, an ultrafast lattice contraction due to the release of magneto-striction leads to a transient shift of the magnetic satellite peak.
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Affiliation(s)
- L Rettig
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Current Address: Abteilung Physikalische Chemie, Fritz-Haber-Institut der MPG, Faradayweg 4-6, D-14195 Berlin, Germany
| | - C Dornes
- Institute for Quantum Electronics, Physics Department, ETH Zürich, 8093 Zürich, Switzerland
| | - N Thielemann-Kühn
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476 Potsdam-Golm, Germany
| | - N Pontius
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - H Zabel
- Institute for Experimental Physics, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - D L Schlagel
- Division of Materials Sciences and Engineering, Ames Laboratory, Ames, Iowa 50011, USA
| | - T A Lograsso
- Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, USA
| | - M Chollet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - A Robert
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - M Sikorski
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - S Song
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - J M Glownia
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - C Schüßler-Langeheine
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - S L Johnson
- Institute for Quantum Electronics, Physics Department, ETH Zürich, 8093 Zürich, Switzerland
| | - U Staub
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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Morrison AK, Patel M, Johnson SL, LeGallo R, Teague WG, Vergales B. Pulmonary interstitial glycogenosis in a patient with trisomy 21. J Neonatal Perinatal Med 2016; 9:227-31. [PMID: 27197936 DOI: 10.3233/npm-16915112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Pulmonary interstitial glycogenosis is an interstitial lung disease of childhood that has been increasingly reported over the past decade. Here, we present a case of pulmonary interstitial glycogenosis associated with trisomy 21, pulmonary arterial hypertension, and congenital heart disease in a 34 week premature infant.
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Affiliation(s)
- A K Morrison
- Department of Pediatrics, University of Virginia, Charlottesville, VA, USA; (Currently Department of Pediatrics, Division of Cardiology, Nationwide Children's Hospital)
| | - M Patel
- Division of Neonatology, Department of Pediatrics, University of Virginia, Charlottesville, VA, USA; (Currently Division of Neonatology in the Department of Pediatrics at MedStar Franklin Square Hospital)
| | - S L Johnson
- Department of Pathology, University of Virginia, Charlottesville, VA, USA
| | - R LeGallo
- Department of Pathology, University of Virginia, Charlottesville, VA, USA
| | - W G Teague
- Division of Pulmonology, Department of Pediatrics, University of Virginia, Charlottesville, VA, USA
| | - B Vergales
- Division of Neonatology, Department of Pediatrics, University of Virginia, Charlottesville, VA, USA
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Rettig L, Mariager SO, Ferrer A, Grübel S, Johnson JA, Rittmann J, Wolf T, Johnson SL, Ingold G, Beaud P, Staub U. Ultrafast structural dynamics of the orthorhombic distortion in the Fe-pnictide parent compound BaFe2As2. Struct Dyn 2016; 3:023611. [PMID: 27158636 PMCID: PMC4841800 DOI: 10.1063/1.4947250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 04/09/2016] [Indexed: 05/19/2023]
Abstract
Using femtosecond time-resolved hard x-ray diffraction, we investigate the structural dynamics of the orthorhombic distortion in the Fe-pnictide parent compound BaFe2As2. The orthorhombic distortion analyzed by the transient splitting of the (1 0 3) Bragg reflection is suppressed on an initial timescale of 35 ps, which is much slower than the suppression of magnetic and nematic order. This observation demonstrates a transient state with persistent structural distortion and suppressed magnetic/nematic order which are strongly linked in thermal equilibrium. We suggest a way of quantifying the coupling between structural and nematic degrees of freedom based on the dynamics of the respective order parameters.
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Affiliation(s)
- L Rettig
- Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland
| | - S O Mariager
- Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland
| | | | - S Grübel
- Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland
| | - J A Johnson
- Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland
| | | | - T Wolf
- Karlsruhe Institute of Technology , Institut für Festkörperphysik, D-76021 Karlsruhe, Germany
| | - S L Johnson
- Institute for Quantum Electronics, ETH Zürich , CH-8093 Zürich, Switzerland
| | | | | | - U Staub
- Swiss Light Source, Paul Scherrer Institut , CH-5232 Villigen PSI, Switzerland
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Buniello A, Ingham NJ, Lewis MA, Huma AC, Martinez-Vega R, Varela-Nieto I, Vizcay-Barrena G, Fleck RA, Houston O, Bardhan T, Johnson SL, White JK, Yuan H, Marcotti W, Steel KP. Wbp2 is required for normal glutamatergic synapses in the cochlea and is crucial for hearing. EMBO Mol Med 2016; 8:191-207. [PMID: 26881968 PMCID: PMC4772953 DOI: 10.15252/emmm.201505523] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 12/18/2015] [Accepted: 12/21/2015] [Indexed: 01/01/2023] Open
Abstract
WBP2 encodes the WW domain-binding protein 2 that acts as a transcriptional coactivator for estrogen receptor α (ESR1) and progesterone receptor (PGR). We reported that the loss of Wbp2 expression leads to progressive high-frequency hearing loss in mouse, as well as in two deaf children, each carrying two different variants in the WBP2 gene. The earliest abnormality we detect in Wbp2-deficient mice is a primary defect at inner hair cell afferent synapses. This study defines a new gene involved in the molecular pathway linking hearing impairment to hormonal signalling and provides new therapeutic targets.
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Affiliation(s)
- Annalisa Buniello
- Wolfson Centre For Age-Related Diseases, King's College London, London, UK Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Neil J Ingham
- Wolfson Centre For Age-Related Diseases, King's College London, London, UK Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Morag A Lewis
- Wolfson Centre For Age-Related Diseases, King's College London, London, UK Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Andreea C Huma
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Raquel Martinez-Vega
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid, Spain Centre for Biomedical Network Research on Rare Diseases (CIBERER), Unit 761, Instituto de Salud Carlos III, Madrid, Spain
| | - Isabel Varela-Nieto
- Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, Madrid, Spain Centre for Biomedical Network Research on Rare Diseases (CIBERER), Unit 761, Instituto de Salud Carlos III, Madrid, Spain
| | | | - Roland A Fleck
- Centre for Ultrastructural Imaging, King's College London, London, UK
| | - Oliver Houston
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Tanaya Bardhan
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Stuart L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Jacqueline K White
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Huijun Yuan
- Medical Genetics Center, Southwest Hospital Third Military Medical University, Chongqing, China
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Karen P Steel
- Wolfson Centre For Age-Related Diseases, King's College London, London, UK Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
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Johnson SL. Preface to Special Topic: Invited Papers of the 3rd International Conference on Ultrafast Structural Dynamics. Struct Dyn 2016; 3:023401. [PMID: 27191008 PMCID: PMC4851626 DOI: 10.1063/1.4947078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 04/06/2016] [Indexed: 06/05/2023]
Abstract
The ability to visualize the real-time dynamics of atomic, magnetic, and electronic structure is widely recognized in many fields as a key element underpinning many important processes in chemistry, materials science, and biology. The need for an improved understanding of such processes becomes acute as energy conversion processes on fast time scales become increasingly relevant to problems in science and technology. This special issue, containing invited papers from participants at the 3rd International Conference on Ultrafast Structural Dynamics held June 10-12, 2015 in Zurich, Switzerland, discusses several recent developments in this area.
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Affiliation(s)
- S L Johnson
- Institute for Quantum Electronics , Eidgenössische Technische Hochschule (ETH) Zurich, 8093 Zürich, Switzerland
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Abstract
The auditory pathway faithfully encodes and relays auditory information to the brain with remarkable speed and precision. The inner hair cells (IHCs) are the primary sensory receptors adapted for rapid auditory signaling, but they are not thought to be intrinsically tuned to encode particular sound frequencies. Here I found that under experimental conditions mimicking those in vivo, mammalian IHCs are intrinsically specialized. Low-frequency gerbil IHCs (~0.3 kHz) have significantly more depolarized resting membrane potentials, faster kinetics, and shorter membrane time constants than high-frequency cells (~30 kHz). The faster kinetics of low-frequency IHCs allow them to follow the phasic component of sound (frequency-following), which is not required for high-frequency cells that are instead optimally configured to encode sustained, graded responses (intensity-following). The intrinsic membrane filtering of IHCs ensures accurate encoding of the phasic or sustained components of the cell’s in vivo receptor potential, crucial for sound localization and ultimately survival. DOI:http://dx.doi.org/10.7554/eLife.08177.001 Many animals’ survival depends on them accurately and quickly identifying sounds in their environment. In animals with backbones, cells with hair-like projections (called hair cells) inside the ear convert information collected from sound waves into electrical signals. These signals are then transmitted to the brain, which processes the information further. Animals like bullfrogs are adapted to hearing low frequency sounds, like their own mating calls. These frog’s hair cells are individually tuned so that they can capture sounds in this low frequency range. Mammals, on the other hand, have evolved to hear a much wider range of sounds from loud and low frequency sounds, such as thunder, to soft and high frequency sounds, like the cries of their young. In mammals, the part of inner ear involved in hearing (called the cochlea) has an elaborate spiral-like shape. The structure of the cochlea results in different frequencies of sound being transformed by the hair cells into electrical signals at different points around the spiral. Because of this, most researchers didn’t think that hair cells in mammals were individually tuned like those in bullfrogs. Now, Stuart Johnson demonstrates that hair cells in different parts of the gerbil’s cochlea are specialized for encoding sounds of specific frequencies. In conditions that mimic the environment inside the ear, a very precise jet of fluid was used to stimulate single hair cells in a similar way to a sound wave. The experiments then compared how hair cells from the upper and lower parts of the cochlea’s spiral responded. Johnson found that hair cells from the upper portion of the gerbils’ cochlea are specialized to capture low frequency sounds. They have electrical properties that allow them to quickly transmit information to the brain about low frequency sounds. In the lower portion of the cochlea, hair cells are specialized to capture high frequency sounds. That is, their electrical properties make it easier for these hair cells to transmit detailed information to the brain about the volume of high frequency sounds. Together, these findings help explain how these animals are able to localize sounds, which requires capturing both the timing and intensity of different types of sounds. DOI:http://dx.doi.org/10.7554/eLife.08177.002
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Affiliation(s)
- Stuart L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
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Murray G, Leitan ND, Berk M, Thomas N, Michalak E, Berk L, Johnson SL, Jones S, Perich T, Allen NB, Kyrios M. Online mindfulness-based intervention for late-stage bipolar disorder: pilot evidence for feasibility and effectiveness. J Affect Disord 2015; 178:46-51. [PMID: 25795535 DOI: 10.1016/j.jad.2015.02.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 02/18/2015] [Accepted: 02/23/2015] [Indexed: 01/21/2023]
Abstract
OBJECTIVES People in the late stage of bipolar disorder (BD) experience elevated relapse rates and poorer quality of life (QoL) compared with those in the early stages. Existing psychological interventions also appear less effective in this group. To address this need, we developed a new online mindfulness-based intervention targeting quality of life (QoL) in late stage BD. Here, we report on an open pilot trial of ORBIT (online, recovery-focused, bipolar individual therapy). METHODS Inclusion criteria were: self-reported primary diagnosis of BD, six or more episodes of BD, under the care of a medical practitioner, access to the internet, proficient in English, 18-65 years of age. Primary outcome was change (baseline - post-treatment) on the Brief QoL.BD (Michalak and Murray, 2010). Secondary outcomes were depression, anxiety, and stress measured on the DASS scales (Lovibond and Lovibond, 1993). RESULTS Twenty-six people consented to participate (Age M=46.6 years, SD=12.9, and 75% female). Ten participants were lost to follow-up (38.5% attrition). Statistically significant improvement in QoL was found for the completers, t(15)=2.88, 95% CI:.89-5.98, p=.011, (Cohen׳s dz=.72, partial η(2)=.36), and the intent-to-treat sample t(25)=2.65, 95% CI:.47-3.76, (Cohen׳s dz=.52; partial η(2)=.22). A non-significant trend towards improvement was found on the DASS anxiety scale (p=.06) in both completer and intent-to-treat samples, but change on depression and stress did not approach significance. LIMITATIONS This was an open trial with no comparison group, so measured improvements may not be due to specific elements of the intervention. Structured diagnostic assessments were not conducted, and interpretation of effectiveness was limited by substantial attrition. CONCLUSION Online delivery of mindfulness-based psychological therapy for late stage BD appears feasible and effective, and ORBIT warrants full development. Modifications suggested by the pilot study include increasing the 3 weeks duration of the intervention, adding cautions about the impact of extended meditations, and addition of coaching support/monitoring to optimise engagement.
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Affiliation(s)
- G Murray
- Swinburne University, Melbourne, Australia.
| | - N D Leitan
- Swinburne University, Melbourne, Australia
| | - M Berk
- Deakin University, Melbourne, Australia; University of Melbourne, Melbourne, Australia
| | - N Thomas
- Swinburne University, Melbourne, Australia
| | - E Michalak
- University of British Columbia, Vancouver, Canada
| | - L Berk
- University of Melbourne, Melbourne, Australia
| | - S L Johnson
- University of California, Berkeley, Berkeley, USA
| | - S Jones
- Lancaster University, Lancaster, UK
| | - T Perich
- University of New South Wales, Sydney, Australia
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Magistretti J, Spaiardi P, Johnson SL, Masetto S. Elementary properties of Ca(2+) channels and their influence on multivesicular release and phase-locking at auditory hair cell ribbon synapses. Front Cell Neurosci 2015; 9:123. [PMID: 25904847 PMCID: PMC4389406 DOI: 10.3389/fncel.2015.00123] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 03/17/2015] [Indexed: 02/05/2023] Open
Abstract
Voltage-gated calcium (Cav1.3) channels in mammalian inner hair cells (IHCs) open in response to sound and the resulting Ca2+ entry triggers the release of the neurotransmitter glutamate onto afferent terminals. At low to mid sound frequencies cell depolarization follows the sound sinusoid and pulses of transmitter release from the hair cell generate excitatory postsynaptic currents (EPSCs) in the afferent fiber that translate into a phase-locked pattern of action potential activity. The present article summarizes our current understanding on the elementary properties of single IHC Ca2+ channels, and how these could have functional implications for certain, poorly understood, features of synaptic transmission at auditory hair cell ribbon synapses.
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Affiliation(s)
- Jacopo Magistretti
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia Pavia, Italy
| | - Paolo Spaiardi
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy
| | - Stuart L Johnson
- Department of Biomedical Science, University of Sheffield Sheffield, UK
| | - Sergio Masetto
- Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy
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Rettig L, Mariager SO, Ferrer A, Grübel S, Johnson JA, Rittmann J, Wolf T, Johnson SL, Ingold G, Beaud P, Staub U. Ultrafast structural dynamics of the Fe-pnictide parent compound BaFe(2)As(2). Phys Rev Lett 2015; 114:067402. [PMID: 25723244 DOI: 10.1103/physrevlett.114.067402] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Indexed: 05/19/2023]
Abstract
Using femtosecond time-resolved x-ray diffraction we investigate the structural dynamics of the coherently excited A(1g) phonon mode in the Fe-pnictide parent compound BaFe(2)As(2). The fluence dependent intensity oscillations of two specific Bragg reflections with distinctly different sensitivity to the pnictogen height in the compound allow us to quantify the coherent modifications of the Fe-As tetrahedra, indicating a transient increase of the Fe magnetic moments. By a comparison with time-resolved photoemission data, we derive the electron-phonon deformation potential for this particular mode. The value of Δμ/Δz=-(1.0-1.5) eV/Å is comparable with theoretical predictions and demonstrates the importance of this degree of freedom for the electron-phonon coupling in the Fe pnictides.
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Affiliation(s)
- L Rettig
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - S O Mariager
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Ferrer
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland and Institute for Quantum Electronics, Physics Department, ETH Zürich, CH-8093 Zürich, Switzerland
| | - S Grübel
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J A Johnson
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J Rittmann
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland and Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC, FSB, CH-1015 Lausanne, Switzerland
| | - T Wolf
- Karlsruhe Institute of Technology, Institut für Festkörperphysik, D-76021 Karlsruhe, Germany
| | - S L Johnson
- Institute for Quantum Electronics, Physics Department, ETH Zürich, CH-8093 Zürich, Switzerland
| | - G Ingold
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland and SwissFEL, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland and SwissFEL, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - U Staub
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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Zampini V, Johnson SL, Franz C, Knipper M, Holley MC, Magistretti J, Russo G, Marcotti W, Masetto S. Fine Tuning of CaV1.3 Ca2+ channel properties in adult inner hair cells positioned in the most sensitive region of the Gerbil Cochlea. PLoS One 2014; 9:e113750. [PMID: 25409445 PMCID: PMC4237458 DOI: 10.1371/journal.pone.0113750] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 10/28/2014] [Indexed: 01/15/2023] Open
Abstract
Hearing relies on faithful signal transmission by cochlear inner hair cells (IHCs) onto auditory fibres over a wide frequency and intensity range. Exocytosis at IHC ribbon synapses is triggered by Ca2+ inflow through CaV1.3 (L-type) Ca2+ channels. We investigated the macroscopic (whole-cell) and elementary (cell-attached) properties of Ca2+ currents in IHCs positioned at the middle turn (frequency ∼2 kHz) of the adult gerbil cochlea, which is their most sensitive hearing region. Using near physiological recordings conditions (body temperature and a Na+ based extracellular solution), we found that the macroscopic Ca2+ current activates and deactivates very rapidly (time constant below 1 ms) and inactivates slowly and only partially. Single-channel recordings showed an elementary conductance of 15 pS, a sub-ms latency to first opening, and a very low steady-state open probability (Po: 0.024 in response to 500-ms depolarizing steps at ∼−18 mV). The value of Po was significantly larger (0.06) in the first 40 ms of membrane depolarization, which corresponds to the time when most Ca2+ channel openings occurred clustered in bursts (mean burst duration: 19 ms). Both the Po and the mean burst duration were smaller than those previously reported in high-frequency basal IHCs. Finally, we found that middle turn IHCs are likely to express about 4 times more Ca2+ channels per ribbon than basal cells. We propose that middle-turn IHCs finely-tune CaV1.3 Ca2+ channel gating in order to provide reliable information upon timing and intensity of lower-frequency sounds.
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Affiliation(s)
- Valeria Zampini
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Stuart L. Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Christoph Franz
- Department of Otolaryngology, Tübingen Hearing Research Centre, Laboratory of Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Marlies Knipper
- Department of Otolaryngology, Tübingen Hearing Research Centre, Laboratory of Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Matthew C. Holley
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Jacopo Magistretti
- Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia, Italy
| | - Giancarlo Russo
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Sergio Masetto
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- * E-mail:
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Beaud P, Caviezel A, Mariager SO, Rettig L, Ingold G, Dornes C, Huang SW, Johnson JA, Radovic M, Huber T, Kubacka T, Ferrer A, Lemke HT, Chollet M, Zhu D, Glownia JM, Sikorski M, Robert A, Wadati H, Nakamura M, Kawasaki M, Tokura Y, Johnson SL, Staub U. A time-dependent order parameter for ultrafast photoinduced phase transitions. Nat Mater 2014; 13:923-7. [PMID: 25087068 DOI: 10.1038/nmat4046] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 07/01/2014] [Indexed: 05/06/2023]
Abstract
Strongly correlated electron systems often exhibit very strong interactions between structural and electronic degrees of freedom that lead to complex and interesting phase diagrams. For technological applications of these materials it is important to learn how to drive transitions from one phase to another. A key question here is the ultimate speed of such phase transitions, and to understand how a phase transition evolves in the time domain. Here we apply time-resolved X-ray diffraction to directly measure the changes in long-range order during ultrafast melting of the charge and orbitally ordered phase in a perovskite manganite. We find that although the actual change in crystal symmetry associated with this transition occurs over different timescales characteristic of the many electronic and vibrational coordinates of the system, the dynamics of the phase transformation can be well described using a single time-dependent 'order parameter' that depends exclusively on the electronic excitation.
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Affiliation(s)
- P Beaud
- 1] Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland [2] SwissFEL, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - A Caviezel
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - S O Mariager
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - L Rettig
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - G Ingold
- 1] Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland [2] SwissFEL, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - C Dornes
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - S-W Huang
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - J A Johnson
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - M Radovic
- 1] Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland [2] SwissFEL, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - T Huber
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - T Kubacka
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - A Ferrer
- 1] Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland [2] Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - H T Lemke
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M Chollet
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - D Zhu
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - J M Glownia
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M Sikorski
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - A Robert
- LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - H Wadati
- 1] Department of Applied Physics and Quantum-Phase Electronics Center, University of Tokyo, Hongo, Tokyo 113-8656, Japan [2] Institute for Solid State Physics, University of Tokyo, Kashiwanoha 5-1-5, Chiba 277-8581, Japan
| | - M Nakamura
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - M Kawasaki
- 1] Department of Applied Physics and Quantum-Phase Electronics Center, University of Tokyo, Hongo, Tokyo 113-8656, Japan [2] RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Y Tokura
- 1] Department of Applied Physics and Quantum-Phase Electronics Center, University of Tokyo, Hongo, Tokyo 113-8656, Japan [2] RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - S L Johnson
- Institute for Quantum Electronics, ETH Zürich, 8093 Zürich, Switzerland
| | - U Staub
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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Taylor R, Bullen A, Johnson SL, Grimm-Günter EM, Rivero F, Marcotti W, Forge A, Daudet N. Absence of plastin 1 causes abnormal maintenance of hair cell stereocilia and a moderate form of hearing loss in mice. Hum Mol Genet 2014; 24:37-49. [PMID: 25124451 PMCID: PMC4262491 DOI: 10.1093/hmg/ddu417] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Hearing relies on the mechanosensory inner and outer hair cells (OHCs) of the organ of Corti, which convert mechanical deflections of their actin-rich stereociliary bundles into electrochemical signals. Several actin-associated proteins are essential for stereocilia formation and maintenance, and their absence leads to deafness. One of the most abundant actin-bundling proteins of stereocilia is plastin 1, but its function has never been directly assessed. Here, we found that plastin 1 knock-out (Pls1 KO) mice have a moderate and progressive form of hearing loss across all frequencies. Auditory hair cells developed normally in Pls1 KO, but in young adult animals, the stereocilia of inner hair cells were reduced in width and length. The stereocilia of OHCs were comparatively less affected; however, they also showed signs of degeneration in ageing mice. The hair bundle stiffness and the acquisition of the electrophysiological properties of hair cells were unaffected by the absence of plastin 1, except for a significant change in the adaptation properties, but not the size of the mechanoelectrical transducer currents. These results show that in contrast to other actin-bundling proteins such as espin, harmonin or Eps8, plastin 1 is dispensable for the initial formation of stereocilia. However, the progressive hearing loss and morphological defects of hair cells in adult Pls1 KO mice point at a specific role for plastin 1 in the preservation of adult stereocilia and optimal hearing. Hence, mutations in the human PLS1 gene may be associated with relatively mild and progressive forms of hearing loss.
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Affiliation(s)
- Ruth Taylor
- Centre for Auditory Research, UCL Ear Institute, University College London, London, UK
| | - Anwen Bullen
- Centre for Auditory Research, UCL Ear Institute, University College London, London, UK
| | - Stuart L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, UK and
| | - Eva-Maria Grimm-Günter
- Centre for Cardiovascular and Metabolic Research, The Hull York Medical School, University of Hull, Hull, UK
| | - Francisco Rivero
- Centre for Cardiovascular and Metabolic Research, The Hull York Medical School, University of Hull, Hull, UK
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, UK and
| | - Andrew Forge
- Centre for Auditory Research, UCL Ear Institute, University College London, London, UK
| | - Nicolas Daudet
- Centre for Auditory Research, UCL Ear Institute, University College London, London, UK
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Huber T, Mariager SO, Ferrer A, Schäfer H, Johnson JA, Grübel S, Lübcke A, Huber L, Kubacka T, Dornes C, Laulhe C, Ravy S, Ingold G, Beaud P, Demsar J, Johnson SL. Coherent structural dynamics of a prototypical charge-density-wave-to-metal transition. Phys Rev Lett 2014; 113:026401. [PMID: 25062214 DOI: 10.1103/physrevlett.113.026401] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Indexed: 05/19/2023]
Abstract
Using femtosecond time-resolved x-ray diffraction, we directly monitor the coherent lattice dynamics through an ultrafast charge-density-wave-to-metal transition in the prototypical Peierls system K(0.3)MoO(3) over a wide range of relevant excitation fluences. While in the low fluence regime we directly follow the structural dynamics associated with the collective amplitude mode; for fluences above the melting threshold of the electronic density modulation we observe a transient recovery of the periodic lattice distortion. We can describe these structural dynamics as a motion along the coordinate of the Peierls distortion triggered by the prompt collapse of electronic order after photoexcitation. The results indicate that the dynamics of a structural symmetry-breaking transition are determined by a high-symmetry excited state potential energy surface distinct from that of the initial low-temperature state.
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Affiliation(s)
- T Huber
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - S O Mariager
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Ferrer
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland and Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - H Schäfer
- Physics Department, Universität Konstanz, D-78457 Konstanz, Germany
| | - J A Johnson
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - S Grübel
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Lübcke
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland and Laboratoire de Spectroscopie Ultrarapide, EPF Lausanne, CH-1015 Lausanne, Switzerland
| | - L Huber
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - T Kubacka
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - C Dornes
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
| | - C Laulhe
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, FR-91192 Gif-sur-Yvette Cedex, France and Université Paris-Sud, 91405 Orsay Cedex, France
| | - S Ravy
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, FR-91192 Gif-sur-Yvette Cedex, France
| | - G Ingold
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J Demsar
- Physics Department, Universität Konstanz, D-78457 Konstanz, Germany and Institute of Physics, Ilmenau University of Technology, D-98693 Ilmenau, Germany
| | - S L Johnson
- Institute for Quantum Electronics, Physics Department, ETH Zurich, CH-8093 Zurich, Switzerland
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Morton M, Coupes B, Roberts SA, Johnson SL, Klapper PE, Vallely PJ, Picton ML. Epstein-Barr virus infection in adult renal transplant recipients. Am J Transplant 2014; 14:1619-29. [PMID: 24815922 DOI: 10.1111/ajt.12703] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 01/15/2014] [Accepted: 02/05/2014] [Indexed: 01/25/2023]
Abstract
Epstein-Barr virus (EBV) DNAemia in the first year posttransplantation has been studied extensively. There is a paucity of information on prevalence and sequelae of EBV infection in adult renal transplantation beyond the first year. This single-center study examines the relationship between EBV DNAemia and demographic, immunosuppressive, hematologic and infection-related parameters in 499 renal transplant recipients between 1 month and 33 years posttransplant. Participants were tested repeatedly for EBV DNAemia detection over 12 months and clinical progress followed for 3 years. Prevalence of DNAemia at recruitment increased significantly with time from transplant. In multivariate adjusted analyses, variables associated with DNAemia included EBV seronegative status at transplant (p = 0.045), non-White ethnicity (p = 0.014) and previous posttransplant lymphoproliferative disease (PTLD) diagnosis (p = 0.006), while low DNAemia rates were associated with mycophenolate mofetil use (p < 0.0001) and EBV viral capsid antigen positive Epstein-Barr nuclear antigen-1 positive serostatus at transplant (p = 0.044). Patient and graft survival, rate of kidney function decline and patient reported symptoms were not significantly different between EBV DNAemia positive and negative groups. EBV DNAemia is common posttransplant and increases with time from transplantation, but EBV DNAemia detection in low-risk (seropositive) patients has poor specificity as a biomarker for future PTLD risk.
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Affiliation(s)
- M Morton
- Department of Renal Medicine, Central Manchester University Hospitals Foundation Trust, Manchester, UK
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41
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Johnson SL, Wedemeyer C, Vetter DE, Adachi R, Holley MC, Elgoyhen AB, Marcotti W. Cholinergic efferent synaptic transmission regulates the maturation of auditory hair cell ribbon synapses. Open Biol 2014; 3:130163. [PMID: 24350389 PMCID: PMC3843824 DOI: 10.1098/rsob.130163] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Spontaneous electrical activity generated by developing sensory cells and neurons is crucial for the maturation of neural circuits. The full maturation of mammalian auditory inner hair cells (IHCs) depends on patterns of spontaneous action potentials during a ‘critical period’ of development. The intrinsic spiking activity of IHCs can be modulated by inhibitory input from cholinergic efferent fibres descending from the brainstem, which transiently innervate immature IHCs. However, it remains unknown whether this transient efferent input to developing IHCs is required for their functional maturation. We used a mouse model that lacks the α9-nicotinic acetylcholine receptor subunit (α9nAChR) in IHCs and another lacking synaptotagmin-2 in the efferent terminals to remove or reduce efferent input to IHCs, respectively. We found that the efferent system is required for the developmental linearization of the Ca2+-sensitivity of vesicle fusion at IHC ribbon synapses, without affecting their general cell development. This provides the first direct evidence that the efferent system, by modulating IHC electrical activity, is required for the maturation of the IHC synaptic machinery. The central control of sensory cell development is unique among sensory systems.
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Affiliation(s)
- Stuart L. Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
- e-mail:
| | - Carolina Wedemeyer
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr Héctor N. Torres, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires 1428, Argentina
| | - Douglas E. Vetter
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Roberto Adachi
- Department of Pulmonary Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Matthew C. Holley
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - Ana Belén Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr Héctor N. Torres, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires 1428, Argentina
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
- e-mail:
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42
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Olt J, Johnson SL, Marcotti W. In vivo and in vitro biophysical properties of hair cells from the lateral line and inner ear of developing and adult zebrafish. J Physiol 2014; 592:2041-58. [PMID: 24566541 PMCID: PMC4027864 DOI: 10.1113/jphysiol.2013.265108] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Hair cells detect and process sound and movement information, and transmit this with remarkable precision and efficiency to afferent neurons via specialized ribbon synapses. The zebrafish is emerging as a powerful model for genetic analysis of hair cell development and function both in vitro and in vivo. However, the full exploitation of the zebrafish is currently limited by the difficulty in obtaining systematic electrophysiological recordings from hair cells under physiological recording conditions. Thus, the biophysical properties of developing and adult zebrafish hair cells are largely unknown. We investigated potassium and calcium currents, voltage responses and synaptic activity in hair cells from the lateral line and inner ear in vivo and using near-physiological in vitro recordings. We found that the basolateral current profile of hair cells from the lateral line becomes more segregated with age, and that cells positioned in the centre of the neuromast show more mature characteristics and those towards the edge retain a more immature phenotype. The proportion of mature-like hair cells within a given neuromast increased with zebrafish development. Hair cells from the inner ear showed a developmental change in current profile between the juvenile and adult stages. In lateral line hair cells from juvenile zebrafish, exocytosis also became more efficient and required less calcium for vesicle fusion. In hair cells from mature zebrafish, the biophysical characteristics of ion channels and exocytosis resembled those of hair cells from other lower vertebrates and, to some extent, those in the immature mammalian vestibular and auditory systems. We show that although the zebrafish provides a suitable animal model for studies on hair cell physiology, it is advisable to consider that the age at which the majority of hair cells acquire a mature-type configuration is reached only in the juvenile lateral line and in the inner ear from >2 months after hatching.
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Affiliation(s)
- Jennifer Olt
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Stuart L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
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43
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Olt J, Mburu P, Johnson SL, Parker A, Kuhn S, Bowl M, Marcotti W, Brown SDM. The actin-binding proteins eps8 and gelsolin have complementary roles in regulating the growth and stability of mechanosensory hair bundles of mammalian cochlear outer hair cells. PLoS One 2014; 9:e87331. [PMID: 24475274 PMCID: PMC3903700 DOI: 10.1371/journal.pone.0087331] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 12/19/2013] [Indexed: 11/21/2022] Open
Abstract
Sound transduction depends upon mechanosensitive channels localized on the hair-like bundles that project from the apical surface of cochlear hair cells. Hair bundles show a stair-case structure composed of rows of stereocilia, and each stereocilium contains a core of tightly-packed and uniformly-polarized actin filaments. The growth and maintenance of the stereociliary actin core are dynamically regulated. Recently, it was shown that the actin-binding protein gelsolin is expressed in the stereocilia of outer hair cells (OHCs) and in its absence they become long and straggly. Gelsolin is part of a whirlin scaffolding protein complex at the stereocilia tip, which has been shown to interact with other actin regulatory molecules such as Eps8. Here we investigated the physiological effects associated with the absence of gelsolin and its possible overlapping role with Eps8. We found that, in contrast to Eps8, gelsolin does not affect mechanoelectrical transduction during immature stages of development. Moreover, OHCs from gelsolin knockout mice were able to mature into fully functional sensory receptors as judged by the normal resting membrane potential and basolateral membrane currents. Mechanoelectrical transducer current in gelsolin-Eps8 double knockout mice showed a profile similar to that observed in the single mutants for Eps8. We propose that gelsolin has a non-overlapping role with Eps8. While Eps8 is mainly involved in the initial growth of stereocilia in both inner hair cells (IHCs) and OHCs, gelsolin is required for the maintenance of mature hair bundles of low-frequency OHCs after the onset of hearing.
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MESH Headings
- Adaptor Proteins, Signal Transducing/metabolism
- Animals
- Cytoskeletal Proteins/metabolism
- Gelsolin/genetics
- Gelsolin/metabolism
- Hair Cells, Auditory, Outer/metabolism
- Hair Cells, Auditory, Outer/physiology
- Hair Cells, Auditory, Outer/ultrastructure
- Immunohistochemistry
- Mechanoreceptors/metabolism
- Mechanoreceptors/physiology
- Mechanoreceptors/ultrastructure
- Mechanotransduction, Cellular/physiology
- Mice
- Mice, Knockout
- Microfilament Proteins/metabolism
- Microscopy, Electron, Scanning
- Patch-Clamp Techniques
- Physical Stimulation
- Pyridinium Compounds
- Quaternary Ammonium Compounds
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Affiliation(s)
- Jennifer Olt
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Philomena Mburu
- Medical Research Council (MRC), Mammalian Genetics Unit, Harwell, United Kingdom
| | - Stuart L. Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Andy Parker
- Medical Research Council (MRC), Mammalian Genetics Unit, Harwell, United Kingdom
| | - Stephanie Kuhn
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Mike Bowl
- Medical Research Council (MRC), Mammalian Genetics Unit, Harwell, United Kingdom
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
- * E-mail: (WM); (SDMB)
| | - Steve D. M. Brown
- Medical Research Council (MRC), Mammalian Genetics Unit, Harwell, United Kingdom
- * E-mail: (WM); (SDMB)
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44
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Chen J, Johnson SL, Lewis MA, Hilton JM, Huma A, Marcotti W, Steel KP. A reduction in Ptprq associated with specific features of the deafness phenotype of the miR-96 mutant mouse diminuendo. Eur J Neurosci 2014; 39:744-56. [PMID: 24446963 PMCID: PMC4065360 DOI: 10.1111/ejn.12484] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 12/16/2013] [Accepted: 12/18/2013] [Indexed: 12/23/2022]
Abstract
miR-96 is a microRNA, a non-coding RNA gene which regulates a wide array of downstream genes. The miR-96 mouse mutant diminuendo exhibits deafness and arrested hair cell functional and morphological differentiation. We have previously shown that several genes are markedly downregulated in the diminuendo organ of Corti; one of these is Ptprq, a gene known to be important for maturation and maintenance of hair cells. In order to study the contribution that downregulation of Ptprq makes to the diminuendo phenotype, we carried out microarrays, scanning electron microscopy and single hair cell electrophysiology to compare diminuendo mutants (heterozygous and homozygous) with mice homozygous for a functional null allele of Ptprq. In terms of both morphology and electrophysiology, the auditory phenotype of mice lacking Ptprq resembles that of diminuendo heterozygotes, while diminuendo homozygotes are more severely affected. A comparison of transcriptomes indicates there is a broad similarity between diminuendo homozygotes and Ptprq-null mice. The reduction in Ptprq observed in diminuendo mice appears to be a major contributor to the morphological, transcriptional and electrophysiological phenotype, but does not account for the complete diminuendo phenotype.
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Affiliation(s)
- Jing Chen
- Wellcome Trust Sanger Institute, Cambridge, UK; Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London, SE1 1UL, UK
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45
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Zampini V, Johnson SL, Franz C, Knipper M, Holley MC, Magistretti J, Masetto S, Marcotti W. Burst activity and ultrafast activation kinetics of CaV1.3 Ca²⁺ channels support presynaptic activity in adult gerbil hair cell ribbon synapses. J Physiol 2013; 591:3811-20. [PMID: 23713031 PMCID: PMC3764630 DOI: 10.1113/jphysiol.2013.251272] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Auditory information transfer to afferent neurons relies on precise triggering of neurotransmitter release at the inner hair cell (IHC) ribbon synapses by Ca2+ entry through CaV1.3 Ca2+ channels. Despite the crucial role of CaV1.3 Ca2+ channels in governing synaptic vesicle fusion, their elementary properties in adult mammals remain unknown. Using near-physiological recording conditions we investigated Ca2+ channel activity in adult gerbil IHCs. We found that Ca2+ channels are partially active at the IHC resting membrane potential (−60 mV). At −20 mV, the large majority (>70%) of Ca2+ channel first openings occurred with an estimated delay of about 50 μs in physiological conditions, with a mean open time of 0.5 ms. Similar to other ribbon synapses, Ca2+ channels in IHCs showed a low mean open probability (0.21 at −20 mV), but this increased significantly (up to 0.91) when Ca2+ channel activity switched to a bursting modality. We propose that IHC Ca2+ channels are sufficiently rapid to transmit fast signals of sound onset and support phase-locking. Short-latency Ca2+ channel opening coupled to multivesicular release would ensure precise and reliable signal transmission at the IHC ribbon synapse.
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Affiliation(s)
- Valeria Zampini
- Department of Biomedical Science, University of Sheffield, UK
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46
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Chuang YD, Lee WS, Kung YF, Sorini AP, Moritz B, Moore RG, Patthey L, Trigo M, Lu DH, Kirchmann PS, Yi M, Krupin O, Langner M, Zhu Y, Zhou SY, Reis DA, Huse N, Robinson JS, Kaindl RA, Schoenlein RW, Johnson SL, Först M, Doering D, Denes P, Schlotter WF, Turner JJ, Sasagawa T, Hussain Z, Shen ZX, Devereaux TP. Real-time manifestation of strongly coupled spin and charge order parameters in stripe-ordered La(1.75)Sr(0.25)NiO(4) nickelate crystals using time-resolved resonant x-ray diffraction. Phys Rev Lett 2013; 110:127404. [PMID: 25166848 DOI: 10.1103/physrevlett.110.127404] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Indexed: 05/19/2023]
Abstract
We investigate the order parameter dynamics of the stripe-ordered nickelate, La(1.75)Sr(0.25)NiO(4), using time-resolved resonant x-ray diffraction. In spite of distinct spin and charge energy scales, the two order parameters' amplitude dynamics are found to be linked together due to strong coupling. Additionally, the vector nature of the spin sector introduces a longer reorientation time scale which is absent in the charge sector. These findings demonstrate that the correlation linking the symmetry-broken states does not unbind during the nonequilibrium process, and the time scales are not necessarily associated with the characteristic energy scales of individual degrees of freedom.
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Affiliation(s)
- Y D Chuang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - W S Lee
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA
| | - Y F Kung
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA
| | - A P Sorini
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA and Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - B Moritz
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA and Department of Physics and Astrophysics, University of North Dakota, Grand Forks, North Dakota 58202, USA and Department of Physics, Northern Illinois University, DeKalb, Illinois 60115, USA
| | - R G Moore
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA
| | - L Patthey
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA and Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
| | - M Trigo
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA and SLAC National Accelerator Laboratory, Stanford PULSE Institute, Menlo Park, California 94025, USA
| | - D H Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - P S Kirchmann
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA
| | - M Yi
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA
| | - O Krupin
- European XFEL GmbH, 22607 Hamburg, Germany and Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - M Langner
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Y Zhu
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - S Y Zhou
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - D A Reis
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA and SLAC National Accelerator Laboratory, Stanford PULSE Institute, Menlo Park, California 94025, USA
| | - N Huse
- Max-Planck Department for Structural Dynamics, Center for Free Electron Laser Science, University of Hamburg, 22761 Hamburg, Germany
| | - J S Robinson
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - R A Kaindl
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - R W Schoenlein
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - S L Johnson
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
| | - M Först
- Max-Planck Department for Structural Dynamics, Center for Free Electron Laser Science, University of Hamburg, 22761 Hamburg, Germany
| | - D Doering
- Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - P Denes
- Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - W F Schlotter
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - J J Turner
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94720, USA
| | - T Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - Z Hussain
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Z X Shen
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA
| | - T P Devereaux
- SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025, USA
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47
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Eckrich T, Varakina K, Johnson SL, Franz C, Singer W, Kuhn S, Knipper M, Holley MC, Marcotti W. Development and function of the voltage-gated sodium current in immature mammalian cochlear inner hair cells. PLoS One 2012; 7:e45732. [PMID: 23029208 PMCID: PMC3446918 DOI: 10.1371/journal.pone.0045732] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 08/14/2012] [Indexed: 12/19/2022] Open
Abstract
Inner hair cells (IHCs), the primary sensory receptors of the mammalian cochlea, fire spontaneous Ca2+ action potentials before the onset of hearing. Although this firing activity is mainly sustained by a depolarizing L-type (CaV1.3) Ca2+ current (ICa), IHCs also transiently express a large Na+ current (INa). We aimed to investigate the specific contribution of INa to the action potentials, the nature of the channels carrying the current and whether the biophysical properties of INa differ between low- and high-frequency IHCs. We show that INa is highly temperature-dependent and activates at around −60 mV, close to the action potential threshold. Its size was larger in apical than in basal IHCs and between 5% and 20% should be available at around the resting membrane potential (−55 mV/−60 mV). However, in vivo the availability of INa could potentially increase to >60% during inhibitory postsynaptic potential activity, which transiently hyperpolarize IHCs down to as far as −70 mV. When IHCs were held at −60 mV and INa elicited using a simulated action potential as a voltage command, we found that INa contributed to the subthreshold depolarization and upstroke of an action potential. We also found that INa is likely to be carried by the TTX-sensitive channel subunits NaV1.1 and NaV1.6 in both apical and basal IHCs. The results provide insight into how the biophysical properties of INa in mammalian cochlear IHCs could contribute to the spontaneous physiological activity during cochlear maturation in vivo.
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Affiliation(s)
- Tobias Eckrich
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Ksenya Varakina
- Department of Otolaryngology, Tübingen Hearing Research Center, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Stuart L. Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Christoph Franz
- Department of Otolaryngology, Tübingen Hearing Research Center, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Wibke Singer
- Department of Otolaryngology, Tübingen Hearing Research Center, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Stephanie Kuhn
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Marlies Knipper
- Department of Otolaryngology, Tübingen Hearing Research Center, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Matthew C. Holley
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
- * E-mail: (MH); (WM)
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
- * E-mail: (MH); (WM)
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48
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Chen W, Jongkamonwiwat N, Abbas L, Eshtan SJ, Johnson SL, Kuhn S, Milo M, Thurlow JK, Andrews PW, Marcotti W, Moore HD, Rivolta MN. Restoration of auditory evoked responses by human ES-cell-derived otic progenitors. Nature 2012; 490:278-82. [PMID: 22972191 PMCID: PMC3480718 DOI: 10.1038/nature11415] [Citation(s) in RCA: 250] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Accepted: 07/16/2012] [Indexed: 12/23/2022]
Abstract
Deafness is a condition with a high prevalence worldwide, produced primarily by the loss of the sensory hair cells and their associated spiral ganglion neurons (SGNs). Of all the forms of deafness, auditory neuropathy is of a particular concern. This condition, defined primarily by damage to the SGNs with relative preservation of the hair cells 1, is responsible for a substantial proportion of patients with hearing impairment 2. While the loss of hair cells can be circumvented partially by a cochlear implant, no routine treatment is available for sensory neuron loss since poor innervation limits the prospective performance of an implant 3. Using stem cells to recover the damaged sensory circuitry is a potential therapeutic strategy. Here, we present a protocol to induce differentiation from human embryonic stem cells (hESCs) using signals involved in the initial specification of the otic placode. We obtained two types of otic progenitors able to differentiate in vitro into hair cell-like cells and auditory neurons that display expected electrophysiological properties. Moreover, when transplanted into an auditory neuropathy model, otic neuroprogenitors engraft, differentiate and significantly improve auditory evoked response (ABR) thresholds. These results should stimulate further research into the development of a cell-based therapy for deafness.
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Affiliation(s)
- Wei Chen
- Centre for Stem Cell Biology, University of Sheffield, Sheffield S10 2TN, UK
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49
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Mariager SO, Pressacco F, Ingold G, Caviezel A, Möhr-Vorobeva E, Beaud P, Johnson SL, Milne CJ, Mancini E, Moyerman S, Fullerton EE, Feidenhans'l R, Back CH, Quitmann C. Structural and magnetic dynamics of a laser induced phase transition in FeRh. Phys Rev Lett 2012; 108:087201. [PMID: 22463562 DOI: 10.1103/physrevlett.108.087201] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Indexed: 05/19/2023]
Abstract
We use time-resolved x-ray diffraction and magneto-optical Kerr effect to study the laser-induced antiferromagnetic to ferromagnetic phase transition in FeRh. The structural response is given by the nucleation of independent ferromagnetic domains (τ(1)~30 ps). This is significantly faster than the magnetic response (τ(2)~60 ps) given by the subsequent domain realignment. X-ray diffraction shows that the two phases coexist on short time scales and that the phase transition is limited by the speed of sound. A nucleation model describing both the structural and magnetic dynamics is presented.
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Affiliation(s)
- S O Mariager
- Swiss Light Source, Paul Scherrer Institut, 5232 Villigen, Switzerland.
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50
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Johnson SL, de Souza RA, Staub U, Beaud P, Möhr-Vorobeva E, Ingold G, Caviezel A, Scagnoli V, Schlotter WF, Turner JJ, Krupin O, Lee WS, Chuang YD, Patthey L, Moore RG, Lu D, Yi M, Kirchmann PS, Trigo M, Denes P, Doering D, Hussain Z, Shen ZX, Prabhakaran D, Boothroyd AT. Femtosecond dynamics of the collinear-to-spiral antiferromagnetic phase transition in CuO. Phys Rev Lett 2012; 108:037203. [PMID: 22400779 DOI: 10.1103/physrevlett.108.037203] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2011] [Indexed: 05/19/2023]
Abstract
We report on the ultrafast dynamics of magnetic order in a single crystal of CuO at a temperature of 207 K in response to strong optical excitation using femtosecond resonant x-ray diffraction. In the experiment, a femtosecond laser pulse induces a sudden, nonequilibrium increase in magnetic disorder. After a short delay ranging from 400 fs to 2 ps, we observe changes in the relative intensity of the magnetic ordering diffraction peaks that indicate a shift from a collinear commensurate phase to a spiral incommensurate phase. These results indicate that the ultimate speed for this antiferromagnetic reorientation transition in CuO is limited by the long-wavelength magnetic excitation connecting the two phases.
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Affiliation(s)
- S L Johnson
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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