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Mukherjee D, Xue B, Chen CT, Chang M, Kao JPY, Kanold PO. Early retinal deprivation crossmodally alters nascent subplate circuits and activity in the auditory cortex during the precritical period. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.21.529453. [PMID: 36865142 PMCID: PMC9980129 DOI: 10.1101/2023.02.21.529453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Sensory perturbation in one modality results in adaptive reorganization of neural pathways within the spared modalities, a phenomenon known as "crossmodal plasticity", which has been examined during or after the classic 'critical period'. Because peripheral perturbations can alter auditory cortex (ACX) activity and functional connectivity of the ACX subplate neurons (SPNs) even before the classic critical period, called the precritical period, we investigated if retinal deprivation at birth crossmodally alters ACX activity and SPN circuits during the precritical period. We deprived newborn mice of visual inputs after birth by performing bilateral enucleation. We performed in vivo imaging in the ACX of awake pups during the first two postnatal weeks to investigate cortical activity. We found that enucleation alters spontaneous and sound-evoked activity in the ACX in an age-dependent manner. Next, we performed whole-cell patch clamp recording combined with laser scanning photostimulation in ACX slices to investigate circuit changes in SPNs. We found that enucleation alters the intracortical inhibitory circuits impinging on SPNs shifting the excitation-inhibition balance towards excitation and this shift persists after ear opening. Together, our results indicate that crossmodal functional changes exist in the developing sensory cortices at early ages before the onset of the classic critical period.
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2
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Deng R, Kao JPY, Kanold PO. Aberrant development of excitatory circuits to inhibitory neurons in the primary visual cortex after neonatal binocular enucleation. Sci Rep 2021; 11:3163. [PMID: 33542365 PMCID: PMC7862622 DOI: 10.1038/s41598-021-82679-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 01/22/2021] [Indexed: 11/09/2022] Open
Abstract
The development of GABAergic interneurons is important for the functional maturation of cortical circuits. After migrating into the cortex, GABAergic interneurons start to receive glutamatergic connections from cortical excitatory neurons and thus gradually become integrated into cortical circuits. These glutamatergic connections are mediated by glutamate receptors including AMPA and NMDA receptors and the ratio of AMPA to NMDA receptors decreases during development. Since previous studies have shown that retinal input can regulate the early development of connections along the visual pathway, we investigated if the maturation of glutamatergic inputs to GABAergic interneurons in the visual cortex requires retinal input. We mapped the spatial pattern of glutamatergic connections to layer 4 (L4) GABAergic interneurons in mouse visual cortex at around postnatal day (P) 16 by laser-scanning photostimulation and investigated the effect of binocular enucleations at P1/P2 on these patterns. Gad2-positive interneurons in enucleated animals showed an increased fraction of AMPAR-mediated input from L2/3 and a decreased fraction of input from L5/6. Parvalbumin-expressing (PV) interneurons showed similar changes in relative connectivity. NMDAR-only input was largely unchanged by enucleation. Our results show that retinal input sculpts the integration of interneurons into V1 circuits and suggest that the development of AMPAR- and NMDAR-only connections might be regulated differently.
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Affiliation(s)
- Rongkang Deng
- Department of Biology, University of Maryland, College Park, MD, 20742, USA.,Biological Sciences Graduate Program, University of Maryland, College Park, 20742, MD, USA
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Patrick O Kanold
- Department of Biomedical Engineering, Johns Hopkins University, 379 Miller Res. Bldg, Baltimore, MD, 21205, USA. .,Department of Biology, University of Maryland, College Park, MD, 20742, USA.
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3
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Sheikh A, Meng X, Liu J, Mikhailova A, Kao JPY, McQuillen PS, Kanold PO. Neonatal Hypoxia-Ischemia Causes Functional Circuit Changes in Subplate Neurons. Cereb Cortex 2020; 29:765-776. [PMID: 29365081 DOI: 10.1093/cercor/bhx358] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 12/21/2017] [Indexed: 01/16/2023] Open
Abstract
Neonatal hypoxia-ischemia (HI) in the preterm human results in damage to subcortical developing white matter and cognitive impairments. Subplate neurons (SPNs) are among the first-born cortical neurons and are necessary for normal cerebral development. While moderate or severe HI at P1 in rats leads to SPN loss, it is unclear if HI, esp. forms not associated with overt cell loss lead to altered SPN circuits. Thus, we used two HI models with different severities in P1 rats. Cauterization of the common carotid artery (CCA) causes a largely transient and thus milder ischemia (HI-Caut) while CCA ligation causes more severe ischemia (HI-Lig). While HI-Lig caused subplate damage, HI-Caut did not cause overt histological damage on the light microscopic level. We used laser-scanning photostimulation (LSPS) in acute thalamocortical slices of auditory cortex during P5-10 to study the functional connectivity of SPNs. Both HI categories resulted in hyperconnectivity of excitatory and inhibitory circuits to SPNs. Thus, alterations on the circuit level are present in the absence of cell loss. Our results show that SPN circuits are uniquely susceptible to HI. Given the key developmental role of SPNs, our results suggest that altered SPN circuits might underlie the abnormal development of cortical function after HI.
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Affiliation(s)
- Aminah Sheikh
- Department of Biology, University of Maryland, College Park, MD, USA.,Neuroscience and Cognitive Science Program, University of Maryland, College Park, MD, USA
| | - Xiangying Meng
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Ji Liu
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Alexandra Mikhailova
- Departments of Pediatrics and Neurology, University of California, San Francisco, CA, USA
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Patrick S McQuillen
- Departments of Pediatrics and Neurology, University of California, San Francisco, CA, USA
| | - Patrick O Kanold
- Department of Biology, University of Maryland, College Park, MD, USA.,Neuroscience and Cognitive Science Program, University of Maryland, College Park, MD, USA
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4
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Suga M, Shimada A, Akita F, Shen JR, Tosha T, Sugimoto H. Time-resolved studies of metalloproteins using X-ray free electron laser radiation at SACLA. Biochim Biophys Acta Gen Subj 2019; 1864:129466. [PMID: 31678142 DOI: 10.1016/j.bbagen.2019.129466] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/02/2019] [Accepted: 10/04/2019] [Indexed: 01/12/2023]
Abstract
BACKGROUND The invention of the X-ray free-electron laser (XFEL) has provided unprecedented new opportunities for structural biology. The advantage of XFEL is an intense pulse of X-rays and a very short pulse duration (<10 fs) promising a damage-free and time-resolved crystallography approach. SCOPE OF REVIEW Recent time-resolved crystallographic analyses in XFEL facility SACLA are reviewed. Specifically, metalloproteins involved in the essential reactions of bioenergy conversion including photosystem II, cytochrome c oxidase and nitric oxide reductase are described. MAJOR CONCLUSIONS XFEL with pump-probe techniques successfully visualized the process of the reaction and the dynamics of a protein. Since the active center of metalloproteins is very sensitive to the X-ray radiation, damage-free structures obtained by XFEL are essential to draw mechanistic conclusions. Methods and tools for sample delivery and reaction initiation are key for successful measurement of the time-resolved data. GENERAL SIGNIFICANCE XFEL is at the center of approaches to gain insight into complex mechanism of structural dynamics and the reactions catalyzed by biological macromolecules. Further development has been carried out to expand the application of time-resolved X-ray crystallography. This article is part of a Special Issue entitled Novel measurement techniques for visualizing 'live' protein molecules.
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Affiliation(s)
- Michihiro Suga
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima Naka, Okayama 700-8530, Japan..
| | - Atsuhiro Shimada
- Graduate School of Applied Biological Sciences and Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan..
| | - Fusamichi Akita
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima Naka, Okayama 700-8530, Japan
| | - Jian-Ren Shen
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima Naka, Okayama 700-8530, Japan
| | - Takehiko Tosha
- Synchrotron Radiation Life Science Instrumentation Team, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Hiroshi Sugimoto
- Synchrotron Radiation Life Science Instrumentation Team, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan..
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5
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Light-triggered release of photocaged therapeutics - Where are we now? J Control Release 2019; 298:154-176. [PMID: 30742854 DOI: 10.1016/j.jconrel.2019.02.006] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 02/04/2019] [Accepted: 02/06/2019] [Indexed: 01/02/2023]
Abstract
The current available therapeutics face several challenges such as the development of ideal drug delivery systems towards the goal of personalized treatments for patients benefit. The application of light as an exogenous activation mechanism has shown promising outcomes, owning to the spatiotemporal confinement of the treatment in the vicinity of the diseased tissue, which offers many intriguing possibilities. Engineering therapeutics with light responsive moieties have been explored to enhance the bioavailability, and drug efficacy either in vitro or in vivo. The tailor-made character turns the so-called photocaged compounds highly desirable to reduce the side effects of drugs and, therefore, have received wide research attention. Herein, we seek to highlight the potential of photocaged compounds to obtain a clear understanding of the mechanisms behind its use in therapeutic delivery. A deep overview on the progress achieved in the design, fabrication as well as current and possible future applications in therapeutics of photocaged compounds is provided, so that novel formulations for biomedical field can be designed.
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6
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Distinct Translaminar Glutamatergic Circuits to GABAergic Interneurons in the Neonatal Auditory Cortex. Cell Rep 2018; 19:1141-1150. [PMID: 28494864 DOI: 10.1016/j.celrep.2017.04.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 02/09/2017] [Accepted: 04/16/2017] [Indexed: 11/23/2022] Open
Abstract
GABAergic activity is important in neocortical development and plasticity. Because the maturation of GABAergic interneurons is regulated by neural activity, the source of excitatory inputs to GABAergic interneurons plays a key role in development. We show, by laser-scanning photostimulation, that layer 4 and layer 5 GABAergic interneurons in the auditory cortex in neonatal mice (<P7) receive extensive translaminar glutamatergic input via NMDAR-only synapses. Extensive translaminar AMPAR-mediated input developed during the second postnatal week, whereas NMDAR-only presynaptic connections decreased. GABAergic interneurons showed two spatial patterns of translaminar connection: inputs originating predominantly from supragranular or from supragranular and infragranular layers, including the subplate, which relays early thalamocortical activity. Sensory deprivation altered the development of translaminar inputs. Thus, distinct translaminar circuits to GABAergic interneurons exist throughout development, and the maturation of excitatory synapses is input-specific. Glutamatergic signaling from subplate and intracortical sources likely plays a role in the maturation of GABAergic interneurons.
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7
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Nagode DA, Meng X, Winkowski DE, Smith E, Khan-Tareen H, Kareddy V, Kao JPY, Kanold PO. Abnormal Development of the Earliest Cortical Circuits in a Mouse Model of Autism Spectrum Disorder. Cell Rep 2017; 18:1100-1108. [PMID: 28147267 PMCID: PMC5488290 DOI: 10.1016/j.celrep.2017.01.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 11/21/2016] [Accepted: 01/05/2017] [Indexed: 12/15/2022] Open
Abstract
Autism spectrum disorder (ASD) involves deficits in speech and sound processing. Cortical circuit changes during early development likely contribute to such deficits. Subplate neurons (SPNs) form the earliest cortical microcircuits and are required for normal development of thalamocortical and intracortical circuits. Prenatal valproic acid (VPA) increases ASD risk, especially when present during a critical time window coinciding with SPN genesis. Using optical circuit mapping in mouse auditory cortex, we find that VPA exposure on E12 altered the functional excitatory and inhibitory connectivity of SPNs. Circuit changes manifested as "patches" of mostly increased connection probability or strength in the first postnatal week and as general hyper-connectivity after P10, shortly after ear opening. These results suggest that prenatal VPA exposure severely affects the developmental trajectory of cortical circuits and that sensory-driven activity may exacerbate earlier, subtle connectivity deficits. Our findings identify the subplate as a possible common pathophysiological substrate of deficits in ASD.
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Affiliation(s)
- Daniel A Nagode
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Xiangying Meng
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Daniel E Winkowski
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Ed Smith
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Hamza Khan-Tareen
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | | | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Patrick O Kanold
- Department of Biology, University of Maryland, College Park, MD 20742, USA.
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8
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Muralidharan S, Dirda NDA, Katz EJ, Tang CM, Bandyopadhyay S, Kanold PO, Kao JPY. Ncm, a Photolabile Group for Preparation of Caged Molecules: Synthesis and Biological Application. PLoS One 2016; 11:e0163937. [PMID: 27695074 PMCID: PMC5047466 DOI: 10.1371/journal.pone.0163937] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 09/16/2016] [Indexed: 01/27/2023] Open
Abstract
Ncm, 6-nitrocoumarin-7-ylmethyl, is a photolabile protective group useful for making “caged” molecules. Ncm marries the reliable photochemistry of 2-nitrobenzyl systems with the excellent stability and spectroscopic properties of the coumarin chromophore. From simple, commercially available starting materials, preparation of Ncm and its caged derivatives is both quick and easy. Photorelease of Ncm-caged molecules occurs on the microsecond time scale, with quantum efficiencies of 0.05–0.08. We report the synthesis and physical properties of Ncm and its caged derivatives. The utility of Ncm-caged glutamate for neuronal photostimulation is demonstrated in cultured hippocampal neurons and in brain slice preparations.
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Affiliation(s)
- Sukumaran Muralidharan
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Nathaniel D. A. Dirda
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Elizabeth J. Katz
- Program in Neuroscience, University of Maryland, Baltimore, Baltimore, Maryland, United States of America
- Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Cha-Min Tang
- Program in Neuroscience, University of Maryland, Baltimore, Baltimore, Maryland, United States of America
- Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Sharba Bandyopadhyay
- Department of Biology, University of Maryland, College Park, Maryland, United States of America
| | - Patrick O. Kanold
- Department of Biology, University of Maryland, College Park, Maryland, United States of America
| | - Joseph P. Y. Kao
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Program in Neuroscience, University of Maryland, Baltimore, Baltimore, Maryland, United States of America
- * E-mail:
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9
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Entwisle B, McMullan S, Bokiniec P, Gross S, Chung R, Withford M. In vitro neuronal depolarization and increased synaptic activity induced by infrared neural stimulation. BIOMEDICAL OPTICS EXPRESS 2016; 7:3211-3219. [PMID: 27699093 PMCID: PMC5030005 DOI: 10.1364/boe.7.003211] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/07/2016] [Accepted: 07/14/2016] [Indexed: 05/11/2023]
Abstract
Neuronal responses to infrared neural stimulation (INS) are explored at the single cell level using patch-clamp electrophysiology. We examined membrane and synaptic responses of solitary tract neurons recorded in acute slices prepared from the Sprague-Dawley rat. Neurons were stimulated using a compact 1890 nm waveguide laser with light delivered to a small target area, comparable to the size of a single cell, via a single-mode fiber. We show that infrared radiation increased spontaneous synaptic event frequency, and evoked steady-state currents and neuronal depolarization. The magnitude of the responses was proportional to laser output.
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Affiliation(s)
- Blake Entwisle
- Department of Physics and Astronomy, Faculty of Science and Engineering, Macquarie University, Australia Centre for Ultrahigh bandwidth Devices for Optical Systems,
Australia
| | - Simon McMullan
- Australian School of Advanced Medicine, Faculty of Human Sciences, Macquarie University,
Australia
| | - Phillip Bokiniec
- Australian School of Advanced Medicine, Faculty of Human Sciences, Macquarie University,
Australia
| | - Simon Gross
- Department of Physics and Astronomy, Faculty of Science and Engineering, Macquarie University, Australia Centre for Ultrahigh bandwidth Devices for Optical Systems,
Australia
| | - Roger Chung
- Australian School of Advanced Medicine, Faculty of Human Sciences, Macquarie University,
Australia
| | - Michael Withford
- Department of Physics and Astronomy, Faculty of Science and Engineering, Macquarie University, Australia Centre for Ultrahigh bandwidth Devices for Optical Systems,
Australia
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10
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Nadler A, Yushchenko DA, Müller R, Stein F, Feng S, Mulle C, Carta M, Schultz C. Exclusive photorelease of signalling lipids at the plasma membrane. Nat Commun 2015; 6:10056. [PMID: 26686736 PMCID: PMC4703838 DOI: 10.1038/ncomms10056] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 10/28/2015] [Indexed: 12/17/2022] Open
Abstract
Photoactivation of caged biomolecules has become a powerful approach to study cellular signalling events. Here we report a method for anchoring and uncaging biomolecules exclusively at the outer leaflet of the plasma membrane by employing a photocleavable, sulfonated coumarin derivative. The novel caging group allows quantifying the reaction progress and efficiency of uncaging reactions in a live-cell microscopy setup, thereby greatly improving the control of uncaging experiments. We synthesized arachidonic acid derivatives bearing the new negatively charged or a neutral, membrane-permeant coumarin caging group to locally induce signalling either at the plasma membrane or on internal membranes in β-cells and brain slices derived from C57B1/6 mice. Uncaging at the plasma membrane triggers a strong enhancement of calcium oscillations in β-cells and a pronounced potentiation of synaptic transmission while uncaging inside cells blocks calcium oscillations in β-cells and causes a more transient effect on neuronal transmission, respectively. The precise subcellular site of arachidonic acid release is therefore crucial for signalling outcome in two independent systems. Caged signalling intermediates are powerful cell biological tools, however it can be challenging to precisely control where activation occurs. Nadler et al. develop a caging group that specifically targets the plasma membrane, and demonstrate spatially controlled activation of arachidonic acid signalling.
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Affiliation(s)
- André Nadler
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Dmytro A Yushchenko
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany.,Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 16610 Prague 6, Czech Republic
| | - Rainer Müller
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Frank Stein
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Suihan Feng
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Christophe Mulle
- Institut Interdisciplinaire de Neurosciences, CNRS UMR 5297 Université Bordeaux 2, 146, rue Léo-Saignat, 33077 Bordeaux, France
| | - Mario Carta
- Institut Interdisciplinaire de Neurosciences, CNRS UMR 5297 Université Bordeaux 2, 146, rue Léo-Saignat, 33077 Bordeaux, France
| | - Carsten Schultz
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
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11
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Abstract
Methods to control neural activity by light have been introduced to the field of neuroscience. During the last decade, several techniques have been established, including optogenetics, thermogenetics, and infrared neural stimulation. The techniques allow investigators to turn-on or turn-off neural activity. This review is an attempt to show the importance of the techniques for the auditory field and provide insight in the similarities, overlap, and differences of the techniques. Discussing the mechanism of each of the techniques will shed light on the abilities and challenges for each of the techniques. The field has been grown tremendously and a review cannot be complete. However, efforts are made to summarize the important points and to refer the reader to excellent papers and reviews to specific topics. This article is part of a Special Issue entitled .
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Affiliation(s)
- Claus-Peter Richter
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA; Dept. of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL 60208, USA; The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60208, USA.
| | - Xiaodong Tan
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, 303 E. Chicago Ave, Searle 12-561, Chicago, IL 60611, USA
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12
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Watkins PV, Kao JPY, Kanold PO. Spatial pattern of intra-laminar connectivity in supragranular mouse auditory cortex. Front Neural Circuits 2014; 8:15. [PMID: 24653677 PMCID: PMC3949116 DOI: 10.3389/fncir.2014.00015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 02/14/2014] [Indexed: 11/30/2022] Open
Abstract
Neuronal responses and topographic organization of feature selectivity in the cerebral cortex are shaped by ascending inputs and by intracortical connectivity. The mammalian primary auditory cortex has a tonotopic arrangement at large spatial scales (greater than 300 microns). This large-scale architecture breaks down in supragranular layers at smaller scales (around 300 microns), where nearby frequency and sound level tuning properties can be quite heterogeneous. Since layer 4 has a more homogeneous architecture, the heterogeneity in supragranular layers might be caused by heterogeneous ascending input or via heterogeneous intralaminar connections. Here we measure the functional 2-dimensional spatial connectivity pattern of the supragranular auditory cortex on micro-column scales. In general connection probability decreases with radial distance from each neuron, but the decrease is steeper in the isofrequency axis leading to an anisotropic distribution of connection probability with respect to the tonotopic axis. In addition to this radial decrease in connection probability we find a patchy organization of inhibitory and excitatory synaptic inputs that is also anisotropic with respect to the tonotopic axis. These periodicities are at spatial scales of ~100 and ~300 μm. While these spatial periodicities show anisotropy in auditory cortex, they are isotropic in visual cortex, indicating region specific differences in intralaminar connections. Together our results show that layer 2/3 neurons in auditory cortex show specific spatial intralaminar connectivity despite the overtly heterogeneous tuning properties.
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Affiliation(s)
- Paul V Watkins
- Department of Biology, University of Maryland, College Park MD, USA
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore MD, USA ; Department of Physiology, University of Maryland School of Medicine, Baltimore MD, USA
| | - Patrick O Kanold
- Department of Biology, University of Maryland, College Park MD, USA ; Institute for Systems Research, University of Maryland, College Park MD, USA
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13
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Shapiro MG, Homma K, Villarreal S, Richter CP, Bezanilla F. Infrared light excites cells by changing their electrical capacitance. Nat Commun 2012; 3:736. [PMID: 22415827 PMCID: PMC3316879 DOI: 10.1038/ncomms1742] [Citation(s) in RCA: 375] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 02/09/2012] [Indexed: 11/09/2022] Open
Abstract
Optical stimulation has enabled important advances in the study of brain function and other biological processes, and holds promise for medical applications ranging from hearing restoration to cardiac pace making. In particular, pulsed laser stimulation using infrared wavelengths >1.5 μm has therapeutic potential based on its ability to directly stimulate nerves and muscles without any genetic or chemical pre-treatment. However, the mechanism of infrared stimulation has been a mystery, hindering its path to the clinic. Here we show that infrared light excites cells through a novel, highly general electrostatic mechanism. Infrared pulses are absorbed by water, producing a rapid local increase in temperature. This heating reversibly alters the electrical capacitance of the plasma membrane, depolarizing the target cell. This mechanism is fully reversible and requires only the most basic properties of cell membranes. Our findings underscore the generality of pulsed infrared stimulation and its medical potential.
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Affiliation(s)
- Mikhail G. Shapiro
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E. 57th Street, GCIS W244, Illinois 60637, USA
- These authors contributed equally to this work
- Present address: Miller Research Institute, University of California at Berkeley, 2536 Channing Way, California 94720, USA
| | - Kazuaki Homma
- Department of Otolaryngology - Head and Neck Surgery, Northwestern University, 303 E. Chicago Ave, Illinois 60611, USA
- These authors contributed equally to this work
| | - Sebastian Villarreal
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E. 57th Street, GCIS W244, Illinois 60637, USA
| | - Claus-Peter Richter
- Department of Otolaryngology - Head and Neck Surgery, Northwestern University, 303 E. Chicago Ave, Illinois 60611, USA
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd, Evanston, Illinois 60208, USA
- The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Dr, Evanston, Illinois 60208, USA
| | - Francisco Bezanilla
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E. 57th Street, GCIS W244, Illinois 60637, USA
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14
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Abstract
Cell migration is required for many physiological processes, including wound repair and embryogenesis, and relies on precisely orchestrated events that are regulated in a spatially and temporally controlled manner. Most traditional approaches for studying migration, such as genetic methods or the use of chemical inhibitors, do not offer insight into these important components of protein function. However, chemical tools, which respond on a more rapid time scale and in localized regions of the cell, are capable of providing more detailed, real-time information. This Review describes these recent approaches to investigate cell migration and focuses on proteins that are activated by light or small molecules, as well as fluorescent sensors of protein activity.
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Affiliation(s)
- Brenda N. Goguen
- Departments of Biology and Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Barbara Imperiali
- Departments of Biology and Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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Faas GC, Mody I. Measuring the kinetics of calcium binding proteins with flash photolysis. Biochim Biophys Acta Gen Subj 2011; 1820:1195-204. [PMID: 22001612 DOI: 10.1016/j.bbagen.2011.09.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 09/22/2011] [Indexed: 11/19/2022]
Abstract
BACKGROUND Calcium-binding proteins (CBPs) are instrumental in the control of Ca2+ signaling. They are the fastest players within the Ca2+ toolkit responding within microseconds to [Ca2+] changes. The CBPs compete for Ca2+ which plays a direct role in modulating Ca2+ transients and the resulting biochemical message. The kinetic properties of the CBPs have to be known to have a good understanding of Ca2+ signaling. SCOPE OF REVIEW Most techniques used to measure binding kinetics are too slow to accurately determine the fast kinetics of most CBP. Furthermore, many CBPs bind Ca2+ in a cooperative way, which should be incorporated in the kinetic modeling. Here we will review a new ultra-fast in vitro technique for measuring Ca2+ binding properties of CBPs following flash photolysis of caged Ca2+. Compartmental modeling is used to resolve the kinetics of fast cooperative Ca2+ binding to CBPs. MAJOR CONCLUSIONS Currently this technique has only been used to quantify the kinetics of three CBPs (calbindin, calretinin and calmodulin), but has already provided remarkable insights into the specific role that these kinetics in Ca2+ signaling. GENERAL SIGNIFICANCE The potential to gain novel insights into Ca2+ signaling by quantifying kinetics of other CBPs using this technique is very promising. This article is part of a Special Issue entitled Biochemical, biophysical and genetic approaches to intracellular calcium signaling.
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Affiliation(s)
- Guido C Faas
- Department of Neurology, UCLA David Geffen School of Medicine, NRB 1, Room 575E, 635 Charles Young Drive South, Los Angeles, CA 90095-7335, USA.
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Westenhoff S, Nazarenko E, Malmerberg E, Davidsson J, Katona G, Neutze R. Time-resolved structural studies of protein reaction dynamics: a smorgasbord of X-ray approaches. Acta Crystallogr A 2010; 66:207-19. [PMID: 20164644 PMCID: PMC2824530 DOI: 10.1107/s0108767309054361] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Accepted: 12/16/2009] [Indexed: 11/26/2022] Open
Abstract
Time-resolved structural studies of proteins have undergone several significant developments during the last decade. Recent developments using time-resolved X-ray methods, such as time-resolved Laue diffraction, low-temperature intermediate trapping, time-resolved wide-angle X-ray scattering and time-resolved X-ray absorption spectroscopy, are reviewed. Proteins undergo conformational changes during their biological function. As such, a high-resolution structure of a protein’s resting conformation provides a starting point for elucidating its reaction mechanism, but provides no direct information concerning the protein’s conformational dynamics. Several X-ray methods have been developed to elucidate those conformational changes that occur during a protein’s reaction, including time-resolved Laue diffraction and intermediate trapping studies on three-dimensional protein crystals, and time-resolved wide-angle X-ray scattering and X-ray absorption studies on proteins in the solution phase. This review emphasizes the scope and limitations of these complementary experimental approaches when seeking to understand protein conformational dynamics. These methods are illustrated using a limited set of examples including myoglobin and haemoglobin in complex with carbon monoxide, the simple light-driven proton pump bacteriorhodopsin, and the superoxide scavenger superoxide reductase. In conclusion, likely future developments of these methods at synchrotron X-ray sources and the potential impact of emerging X-ray free-electron laser facilities are speculated upon.
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Affiliation(s)
- Sebastian Westenhoff
- Department of Chemistry, Biochemistry and Biophysics, University of Gothenburg, Box 462, SE-40530 Gothenburg, Sweden
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