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Garma LD, Harder L, Barba-Reyes JM, Marco Salas S, Díez-Salguero M, Nilsson M, Serrano-Pozo A, Hyman BT, Muñoz-Manchado AB. Interneuron diversity in the human dorsal striatum. Nat Commun 2024; 15:6164. [PMID: 39039043 PMCID: PMC11263574 DOI: 10.1038/s41467-024-50414-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 07/01/2024] [Indexed: 07/24/2024] Open
Abstract
Deciphering the striatal interneuron diversity is key to understanding the basal ganglia circuit and to untangling the complex neurological and psychiatric diseases affecting this brain structure. We performed snRNA-seq and spatial transcriptomics of postmortem human caudate nucleus and putamen samples to elucidate the diversity and abundance of interneuron populations and their inherent transcriptional structure in the human dorsal striatum. We propose a comprehensive taxonomy of striatal interneurons with eight main classes and fourteen subclasses, providing their full transcriptomic identity and spatial expression profile as well as additional quantitative FISH validation for specific populations. We have also delineated the correspondence of our taxonomy with previous standardized classifications and shown the main transcriptomic and class abundance differences between caudate nucleus and putamen. Notably, based on key functional genes such as ion channels and synaptic receptors, we found matching known mouse interneuron populations for the most abundant populations, the recently described PTHLH and TAC3 interneurons. Finally, we were able to integrate other published datasets with ours, supporting the generalizability of this harmonized taxonomy.
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Affiliation(s)
- Leonardo D Garma
- Karolinska Institutet, Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Stockholm, Sweden
| | - Lisbeth Harder
- Karolinska Institutet, Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Stockholm, Sweden
| | - Juan M Barba-Reyes
- Departamento de Anatomía Patológica, Biología Celular, Histología, Historia de la Ciencia, Medicina Legal y Forense y Toxicología. Instituto de Investigación e Innovación Biomédica de Cádiz (INiBICA). University of Cádiz, Cádiz, Spain
| | - Sergio Marco Salas
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Mónica Díez-Salguero
- Departamento de Anatomía Patológica, Biología Celular, Histología, Historia de la Ciencia, Medicina Legal y Forense y Toxicología. Instituto de Investigación e Innovación Biomédica de Cádiz (INiBICA). University of Cádiz, Cádiz, Spain
| | - Mats Nilsson
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Alberto Serrano-Pozo
- Massachusetts General Hospital, Neurology Department, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Bradley T Hyman
- Massachusetts General Hospital, Neurology Department, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Ana B Muñoz-Manchado
- Karolinska Institutet, Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Stockholm, Sweden.
- Departamento de Anatomía Patológica, Biología Celular, Histología, Historia de la Ciencia, Medicina Legal y Forense y Toxicología. Instituto de Investigación e Innovación Biomédica de Cádiz (INiBICA). University of Cádiz, Cádiz, Spain.
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Fin NSH, Yip A, Teo L, Homman-Ludiye J, Bourne JA. Developmental dynamics of the prefrontal cortical SST and PV interneuron networks: Insights from the monkey highlight human-specific features. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.10.602904. [PMID: 39026896 PMCID: PMC11257587 DOI: 10.1101/2024.07.10.602904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
The primate prefrontal cortex (PFC) is a quintessential hub of cognitive functions. Amidst its intricate neural architecture, the interplay of distinct neuronal subtypes, notably parvalbumin (PV) and somatostatin (SST) interneurons (INs), emerge as a cornerstone in sculpting cortical circuitry and governing cognitive processes. While considerable strides have been made in elucidating the developmental trajectory of these neurons in rodent models, our understanding of their postmigration developmental dynamics in primates still needs to be studied. Disruptions to this developmental trajectory can compromise IN function, impairing signal gating and circuit modulation within cortical networks. This study examined the expression patterns of PV and SST, ion transporter KCC2, and ion channel subtypes Kv3.1b, and Nav1.1 - associated with morphophysiological stages of development in the postnatal marmoset monkey in different frontal cortical regions (granular areas 8aD, 8aV, 9, 46; agranular areas 11, 47L). Our results demonstrate that the maturation of PV+ INs extends into adolescence, characterized by discrete epochs associated with specific expression dynamics of ion channel subtypes. Interestingly, we observed a postnatal decrease in SST interneurons, contrasting with studies in rodents. This endeavor broadens our comprehension of primate cortical development and furnishes invaluable insights into the etiology and pathophysiology of neurodevelopmental disorders characterized by perturbations in PV and SST IN function.
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Affiliation(s)
- Nafiseh S Hosseini Fin
- Australian Regenerative Medicine Institute, 15 Innovation Walk, Monash University, Clayton Vic., 3800, Australia
| | - Adrian Yip
- Australian Regenerative Medicine Institute, 15 Innovation Walk, Monash University, Clayton Vic., 3800, Australia
| | - Leon Teo
- Australian Regenerative Medicine Institute, 15 Innovation Walk, Monash University, Clayton Vic., 3800, Australia
| | - Jihane Homman-Ludiye
- Monash MicroImaging, 15 Innovation Walk, Monash University, Clayton, VIC, 3800, Australia
| | - James A Bourne
- Section on Cellular and Cognitive Neurodevelopment, Systems Neurodevelopment Laboratory, National Institute of Mental Health, Bethesda, MD, 20892, USA
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3
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Bertero A, Apicella AJ. Distinct electrophysiological properties of long-range GABAergic and glutamatergic neurons from the lateral amygdala to the auditory cortex of the mouse. J Physiol 2024; 602:1733-1757. [PMID: 38493320 DOI: 10.1113/jp286094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 02/21/2024] [Indexed: 03/18/2024] Open
Abstract
Differentiating between auditory signals of various emotional significance plays a crucial role in an individual's ability to thrive and excel in social interactions and in survival. Multiple approaches, including anatomical studies, electrophysiological investigations, imaging techniques, optogenetics and chemogenetics, have confirmed that the auditory cortex (AC) impacts fear-related behaviours driven by auditory stimuli by conveying auditory information to the lateral amygdala (LA) through long-range excitatory glutamatergic and GABAergic connections. In addition, the LA provides glutamatergic projections to the AC which are important to fear memory expression and are modified by associative fear learning. Here we test the hypothesis that the LA also sends long-range direct inhibitory inputs to the cortex. To address this fundamental question, we used anatomical and electrophysiological approaches, allowing us to directly assess the nature of GABAergic inputs from the LA to the AC in the mouse. Our findings elucidate the existence of a long-range inhibitory pathway from the LA to the AC (LAC) via parvalbumin-expressing (LAC-Parv) and somatostatin-expressing (LAC-SOM) neurons. This research identifies distinct electrophysiological properties for genetically defined long-range GABAergic neurons involved in the communication between the LA and the cortex (LAC-Parv inhibitory projections → AC neurons; LAC-Som inhibitory projections → AC neurons) within the lateral amygdala cortical network. KEY POINTS: The mouse auditory cortex receives inputs from the lateral amygdala. Retrograde viral tracing techniques allowed us to identify two previously undescribed lateral amygdala to auditory cortex (LAC) GABAergic projecting neurons. Extensive electrophysiological, morphological and anatomical characterization of LAC neurons is provided here, demonstrating key differences in the three populations. This study paves the way for a better understanding of the growing complexity of the cortico-amygdala-cortico circuit.
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Affiliation(s)
- Alice Bertero
- Neuroscience Institute, Department of Neuroscience, Developmental and Regenerative Biology, University of Texas at San Antonio, San Antonio, TX, USA
| | - Alfonso Junior Apicella
- Neuroscience Institute, Department of Neuroscience, Developmental and Regenerative Biology, University of Texas at San Antonio, San Antonio, TX, USA
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Moore JR, Nemera MT, D’Souza RD, Hamagami N, Clemens AW, Beard DC, Urman A, Mendoza VR, Gabel HW. Non-CG DNA methylation and MeCP2 stabilize repeated tuning of long genes that distinguish closely related neuron types. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.30.577861. [PMID: 38352532 PMCID: PMC10862856 DOI: 10.1101/2024.01.30.577861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
The extraordinary diversity of neuron types in the mammalian brain is delineated at the highest resolution by subtle gene expression differences that may require specialized molecular mechanisms to be maintained. Neurons uniquely express the longest genes in the genome and utilize neuron-enriched non-CG DNA methylation (mCA) together with the Rett syndrome protein, MeCP2, to control gene expression, but the function of these unique gene structures and machinery in regulating finely resolved neuron type-specific gene programs has not been explored. Here, we employ epigenomic and spatial transcriptomic analyses to discover a major role for mCA and MeCP2 in maintaining neuron type-specific gene programs at the finest scale of cellular resolution. We uncover differential susceptibility to MeCP2 loss in neuronal populations depending on global mCA levels and dissect methylation patterns and intragenic enhancer repression that drive overlapping and distinct gene regulation between neuron types. Strikingly, we show that mCA and MeCP2 regulate genes that are repeatedly tuned to differentiate neuron types at the highest cellular resolution, including spatially resolved, vision-dependent gene programs in the visual cortex. These repeatedly tuned genes display genomic characteristics, including long length, numerous intragenic enhancers, and enrichment for mCA, that predispose them to regulation by MeCP2. Thus, long gene regulation by the MeCP2 pathway maintains differential gene expression between closely-related neurons to facilitate the exceptional cellular diversity in the complex mammalian brain.
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Affiliation(s)
- J. Russell Moore
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Mati T. Nemera
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Rinaldo D. D’Souza
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Nicole Hamagami
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Adam W. Clemens
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Diana C. Beard
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Alaina Urman
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Victoria Rodriguez Mendoza
- Opportunities in Genomic Research Program, McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
| | - Harrison W. Gabel
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
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5
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Pissas KP, Schilling M, Korkmaz A, Tian Y, Gründer S. Melatonin alters the excitability of mouse cerebellar granule neurons by inhibiting voltage-gated sodium, potassium, and calcium channels. J Pineal Res 2024; 76:e12919. [PMID: 37794846 DOI: 10.1111/jpi.12919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/01/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023]
Abstract
Besides its role in the circadian rhythm, the pineal gland hormone melatonin (MLT) also possesses antiepileptogenic, antineoplastic, and cardioprotective properties, among others. The dosages necessary to elicit beneficial effects in these diseases often far surpass physiological concentrations. Although even high doses of MLT are considered to be largely harmless to humans, the possible side effects of pharmacological concentrations are so far not well investigated. In the present study, we report that pharmacological doses of MLT (3 mM) strongly altered the electrophysiological characteristics of cultured primary mouse cerebellar granule cells (CGCs). Using whole-cell patch clamp and ratiometric Ca2+ imaging, we observed that pharmacological concentrations of MLT inhibited several types of voltage-gated Na+ , K+ , and Ca2+ channels in CGCs independently of known MLT-receptors, altering the character and pattern of elicited action potentials (APs) significantly, quickly and reversibly. Specifically, MLT reduced AP frequency, afterhyperpolarization, and rheobase, whereas AP amplitude and threshold potential remained unchanged. The altered biophysical profile of the cells could constitute a possible mechanism underlying the proposed beneficial effects of MLT in brain-related disorders, such as epilepsy. On the other hand, it suggests potential adverse effects of pharmacological MLT concentrations on neurons, which should be considered when using MLT as a pharmacological compound.
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Affiliation(s)
| | - Maria Schilling
- Medical faculty, Institute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Ahmet Korkmaz
- Medical faculty, Institute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Yuemin Tian
- Medical faculty, Institute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Stefan Gründer
- Medical faculty, Institute of Physiology, RWTH Aachen University, Aachen, Germany
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Ma D, Sun C, Manne R, Guo T, Bosc C, Barry J, Magliery T, Andrieux A, Li H, Gu C. A cytoskeleton-membrane interaction conserved in fast-spiking neurons controls movement, emotion, and memory. Mol Psychiatry 2023; 28:3994-4010. [PMID: 37833406 PMCID: PMC10905646 DOI: 10.1038/s41380-023-02286-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 09/20/2023] [Accepted: 09/29/2023] [Indexed: 10/15/2023]
Abstract
The pathogenesis of schizophrenia is believed to involve combined dysfunctions of many proteins including microtubule-associated protein 6 (MAP6) and Kv3.1 voltage-gated K+ (Kv) channel, but their relationship and functions in behavioral regulation are often not known. Here we report that MAP6 stabilizes Kv3.1 channels in parvalbumin-positive (PV+ ) fast-spiking GABAergic interneurons, regulating behavior. MAP6-/- and Kv3.1-/- mice display similar hyperactivity and avoidance reduction. Their proteins colocalize in PV+ interneurons and MAP6 deletion markedly reduces Kv3.1 protein level. We further show that two microtubule-binding modules of MAP6 bind the Kv3.1 tetramerization domain with high affinity, maintaining the channel level in both neuronal soma and axons. MAP6 knockdown by AAV-shRNA in the amygdala or the hippocampus reduces avoidance or causes hyperactivity and recognition memory deficit, respectively, through elevating projection neuron activity. Finally, knocking down Kv3.1 or disrupting the MAP6-Kv3.1 binding in these brain regions causes avoidance reduction and hyperactivity, consistent with the effects of MAP6 knockdown. Thus, disrupting this conserved cytoskeleton-membrane interaction in fast-spiking neurons causes different degrees of functional vulnerability in various neural circuits.
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Affiliation(s)
- Di Ma
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Chao Sun
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
- MCDB graduate program, The Ohio State University, Columbus, OH, USA
| | - Rahul Manne
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Tianqi Guo
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA
| | - Christophe Bosc
- Univ. Grenoble Alpes, Inserm, U1216, CEA, Grenoble Institut Neurosciences, 38000, Grenoble, France
| | - Joshua Barry
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
- IDDRC, Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Thomas Magliery
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA
| | - Annie Andrieux
- Univ. Grenoble Alpes, Inserm, U1216, CEA, Grenoble Institut Neurosciences, 38000, Grenoble, France
| | - Houzhi Li
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA
| | - Chen Gu
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA.
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA.
- MCDB graduate program, The Ohio State University, Columbus, OH, USA.
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7
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Garma L, Harder L, Barba-Reyes J, Diez-Salguero M, Serrano-Pozo A, Hyman B, Munoz-Manchado A. Interneuron diversity in the human dorsal striatum. RESEARCH SQUARE 2023:rs.3.rs-2921627. [PMID: 37292997 PMCID: PMC10246286 DOI: 10.21203/rs.3.rs-2921627/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Deciphering the striatal interneuron diversity is key to understanding the basal ganglia circuit and to untangle the complex neurological and psychiatric diseases affecting this brain structure. We performed snRNA-seq of postmortem human caudate nucleus and putamen samples to elucidate the diversity and abundance of interneuron populations and their transcriptional structure in the human dorsal striatum. We propose a new taxonomy of striatal interneurons with eight main classes and fourteen subclasses and provide their specific markers and some quantitative FISH validation, particularly for a novel PTHLH-expressing population. For the most abundant populations, PTHLH and TAC3, we found matching known mouse interneuron populations based on key functional genes such as ion channels and synaptic receptors. Remarkably, human TAC3 and mouse Th populations share important similarities including the expression of the neuropeptide tachykinin 3. Finally, we were able to integrate other published datasets supporting the generalizability of this new harmonized taxonomy.
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Affiliation(s)
| | | | | | | | | | - Bradley Hyman
- Massachusetts General Hospital, Harvard Medical School
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Zemel BM, Nevue AA, Tavares LES, Dagostin A, Lovell PV, Jin DZ, Mello CV, von Gersdorff H. Motor cortex analogue neurons in songbirds utilize Kv3 channels to generate ultranarrow spikes. eLife 2023; 12:e81992. [PMID: 37158590 PMCID: PMC10241522 DOI: 10.7554/elife.81992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 05/08/2023] [Indexed: 05/10/2023] Open
Abstract
Complex motor skills in vertebrates require specialized upper motor neurons with precise action potential (AP) firing. To examine how diverse populations of upper motor neurons subserve distinct functions and the specific repertoire of ion channels involved, we conducted a thorough study of the excitability of upper motor neurons controlling somatic motor function in the zebra finch. We found that robustus arcopallialis projection neurons (RAPNs), key command neurons for song production, exhibit ultranarrow spikes and higher firing rates compared to neurons controlling non-vocal somatic motor functions (dorsal intermediate arcopallium [AId] neurons). Pharmacological and molecular data indicate that this striking difference is associated with the higher expression in RAPNs of high threshold, fast-activating voltage-gated Kv3 channels, that likely contain Kv3.1 (KCNC1) subunits. The spike waveform and Kv3.1 expression in RAPNs mirror properties of Betz cells, specialized upper motor neurons involved in fine digit control in humans and other primates but absent in rodents. Our study thus provides evidence that songbirds and primates have convergently evolved the use of Kv3.1 to ensure precise, rapid AP firing in upper motor neurons controlling fast and complex motor skills.
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Affiliation(s)
- Benjamin M Zemel
- Vollum Institute, Oregon Health and Science UniversityPortlandUnited States
| | - Alexander A Nevue
- Department of Behavioral Neuroscience, Oregon Health and Science UniversityPortlandUnited States
| | - Leonardo ES Tavares
- Vollum Institute, Oregon Health and Science UniversityPortlandUnited States
- Department of Physics, Pennsylvania State UniversityUniversity ParkUnited States
| | - Andre Dagostin
- Vollum Institute, Oregon Health and Science UniversityPortlandUnited States
| | - Peter V Lovell
- Department of Behavioral Neuroscience, Oregon Health and Science UniversityPortlandUnited States
| | - Dezhe Z Jin
- Department of Physics, Pennsylvania State UniversityUniversity ParkUnited States
| | - Claudio V Mello
- Department of Behavioral Neuroscience, Oregon Health and Science UniversityPortlandUnited States
| | - Henrique von Gersdorff
- Vollum Institute, Oregon Health and Science UniversityPortlandUnited States
- Oregon Hearing Research Center, Oregon Health and Science UniversityPortlandUnited States
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Via G, Baravalle R, Fernandez FR, White JA, Canavier CC. Interneuronal network model of theta-nested fast oscillations predicts differential effects of heterogeneity, gap junctions and short term depression for hyperpolarizing versus shunting inhibition. PLoS Comput Biol 2022; 18:e1010094. [PMID: 36455063 PMCID: PMC9747050 DOI: 10.1371/journal.pcbi.1010094] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 12/13/2022] [Accepted: 11/14/2022] [Indexed: 12/05/2022] Open
Abstract
Theta and gamma oscillations in the hippocampus have been hypothesized to play a role in the encoding and retrieval of memories. Recently, it was shown that an intrinsic fast gamma mechanism in medial entorhinal cortex can be recruited by optogenetic stimulation at theta frequencies, which can persist with fast excitatory synaptic transmission blocked, suggesting a contribution of interneuronal network gamma (ING). We calibrated the passive and active properties of a 100-neuron model network to capture the range of passive properties and frequency/current relationships of experimentally recorded PV+ neurons in the medial entorhinal cortex (mEC). The strength and probabilities of chemical and electrical synapses were also calibrated using paired recordings, as were the kinetics and short-term depression (STD) of the chemical synapses. Gap junctions that contribute a noticeable fraction of the input resistance were required for synchrony with hyperpolarizing inhibition; these networks exhibited theta-nested high frequency oscillations similar to the putative ING observed experimentally in the optogenetically-driven PV-ChR2 mice. With STD included in the model, the network desynchronized at frequencies above ~200 Hz, so for sufficiently strong drive, fast oscillations were only observed before the peak of the theta. Because hyperpolarizing synapses provide a synchronizing drive that contributes to robustness in the presence of heterogeneity, synchronization decreases as the hyperpolarizing inhibition becomes weaker. In contrast, networks with shunting inhibition required non-physiological levels of gap junctions to synchronize using conduction delays within the measured range.
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Affiliation(s)
- Guillem Via
- Louisiana State University Health Sciences Center, Department of Cell Biology and Anatomy, New Orleans, Louisiana, United States of America
| | - Roman Baravalle
- Louisiana State University Health Sciences Center, Department of Cell Biology and Anatomy, New Orleans, Louisiana, United States of America
| | - Fernando R. Fernandez
- Department of Biomedical Engineering, Center for Systems Neuroscience, Neurophotonics Center, Boston University, Boston, Massachusetts, United States of America
| | - John A. White
- Department of Biomedical Engineering, Center for Systems Neuroscience, Neurophotonics Center, Boston University, Boston, Massachusetts, United States of America
| | - Carmen C. Canavier
- Louisiana State University Health Sciences Center, Department of Cell Biology and Anatomy, New Orleans, Louisiana, United States of America
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Kreir M, Floren W, Policarpo R, De Bondt A, Van den Wyngaert I, Teisman A, Gallacher DJ, Lu HR. Is the forming of neuronal network activity in human-induced pluripotent stem cells important for the detection of drug-induced seizure risks? Eur J Pharmacol 2022; 931:175189. [PMID: 35987255 DOI: 10.1016/j.ejphar.2022.175189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 08/03/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND Functional network activity is a characteristic for neuronal cells, and the complexity of the network activity represents the necessary substrate to support complex brain functions. Drugs that drastically increase the neuronal network activity may have a potential higher risk for seizures in human. Although there has been some recent considerable progress made using cultures from different types of human-induced pluripotent stem cell (hiPSC) derived neurons, one of the primary limitations is the lack of - or very low - network activity. METHOD In the present study, we investigated whether the limited neuronal network activity in commercial hiPSC-neurons (CNS.4U®) is capable of detecting drug-induced potential seizure risks. Therefore, we compared the hiPSC-results to those in rat primary neurons with known high neuronal network activity in vitro. RESULTS Gene expression and electrical activity from in vitro developing neuronal networks were assessed at multiple time-points. Transcriptomes of 7, 28, and 50 days in vitro were analyzed and compared to those from human brain tissues. Data from measurements of electrical activity using multielectrode arrays (MEAs) indicate that neuronal networks matured gradually over time, albeit in hiPSC this developed slower than rat primary cultures. The response of neuronal networks to neuronal active reference drugs modulating glutamatergic, acetylcholinergic and GABAergic pathways could be detected in both hiPSC-neurons and rat primary neurons. However, in comparison, GABAergic responses were limited in hiPSC-neurons. CONCLUSION Overall, despite a slower network development and lower network activity, CNS.4U® hiPSC-neurons can be used to detect drug induced changes in neuronal network activity, as shown by well-known seizurogenic drugs (affecting e.g., the Glycine receptor and Na+ channel). However, lower sensitivity to GABA antagonists has been observed.
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Affiliation(s)
- Mohamed Kreir
- Global Safety Pharmacology, Predictive & Investigative Translational Toxicology, Nonclinical Safety, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium.
| | - Wim Floren
- Global Safety Pharmacology, Predictive & Investigative Translational Toxicology, Nonclinical Safety, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Rafaela Policarpo
- Neuroscience Therapeutic Area, Janssen Research & Development, A Division of Janssen Pharmaceutica NV, Belgium
| | - An De Bondt
- High Dimensional & Computational Biology, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Ilse Van den Wyngaert
- High Dimensional & Computational Biology, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Ard Teisman
- Global Safety Pharmacology, Predictive & Investigative Translational Toxicology, Nonclinical Safety, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - David J Gallacher
- Global Safety Pharmacology, Predictive & Investigative Translational Toxicology, Nonclinical Safety, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Hua Rong Lu
- Global Safety Pharmacology, Predictive & Investigative Translational Toxicology, Nonclinical Safety, Janssen Research and Development, A Division of Janssen Pharmaceutica NV, Beerse, Belgium
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11
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Olah VJ, Goettemoeller AM, Rayaprolu S, Dammer EB, Seyfried NT, Rangaraju S, Dimidschstein J, Rowan MJM. Biophysical Kv3 channel alterations dampen excitability of cortical PV interneurons and contribute to network hyperexcitability in early Alzheimer's. eLife 2022; 11:75316. [PMID: 35727131 PMCID: PMC9278953 DOI: 10.7554/elife.75316] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 05/19/2022] [Indexed: 11/13/2022] Open
Abstract
In Alzheimer’s disease (AD), a multitude of genetic risk factors and early biomarkers are known. Nevertheless, the causal factors responsible for initiating cognitive decline in AD remain controversial. Toxic plaques and tangles correlate with progressive neuropathology, yet disruptions in circuit activity emerge before their deposition in AD models and patients. Parvalbumin (PV) interneurons are potential candidates for dysregulating cortical excitability as they display altered action potential (AP) firing before neighboring excitatory neurons in prodromal AD. Here, we report a novel mechanism responsible for PV hypoexcitability in young adult familial AD mice. We found that biophysical modulation of Kv3 channels, but not changes in their mRNA or protein expression, were responsible for dampened excitability in young 5xFAD mice. These K+ conductances could efficiently regulate near-threshold AP firing, resulting in gamma-frequency-specific network hyperexcitability. Thus, biophysical ion channel alterations alone may reshape cortical network activity prior to changes in their expression levels. Our findings demonstrate an opportunity to design a novel class of targeted therapies to ameliorate cortical circuit hyperexcitability in early AD.
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Affiliation(s)
- Viktor J Olah
- Department of Cell Biology, Emory University, Atlanta, United States
| | | | - Sruti Rayaprolu
- Department of Neurology, Emory University, Atlanta, United States
| | - Eric B Dammer
- Department of Biochemistry, Emory University, Atlanta, United States
| | | | | | | | - Matthew J M Rowan
- Department of Cell Biology, Emory University, Atlanta, United States
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12
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Resurgent Na + currents promote ultrafast spiking in projection neurons that drive fine motor control. Nat Commun 2021; 12:6762. [PMID: 34799550 PMCID: PMC8604930 DOI: 10.1038/s41467-021-26521-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 10/08/2021] [Indexed: 11/29/2022] Open
Abstract
The underlying mechanisms that promote precise spiking in upper motor neurons controlling fine motor skills are not well understood. Here we report that projection neurons in the adult zebra finch song nucleus RA display robust high-frequency firing, ultra-narrow spike waveforms, superfast Na+ current inactivation kinetics, and large resurgent Na+ currents (INaR). These properties of songbird pallial motor neurons closely resemble those of specialized large pyramidal neurons in mammalian primary motor cortex. They emerge during the early phases of song development in males, but not females, coinciding with a complete switch of Na+ channel subunit expression from Navβ3 to Navβ4. Dynamic clamping and dialysis of Navβ4's C-terminal peptide into juvenile RA neurons provide evidence that Navβ4, and its associated INaR, promote neuronal excitability. We thus propose that INaR modulates the excitability of upper motor neurons that are required for the execution of fine motor skills.
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13
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Abstract
Eye movements are indispensable for visual image stabilization during self-generated and passive head and body motion and for visual orientation. Eye muscles and neuronal control elements are evolutionarily conserved, with novel behavioral repertoires emerging during the evolution of frontal eyes and foveae. The precise execution of eye movements with different dynamics is ensured by morphologically diverse yet complementary sets of extraocular muscle fibers and associated motoneurons. Singly and multiply innervated muscle fibers are controlled by motoneuronal subpopulations with largely selective premotor inputs from task-specific ocular motor control centers. The morphological duality of the neuromuscular interface is matched by complementary biochemical and molecular features that collectively assign different physiological properties to the motor entities. In contrast, the functionality represents a continuum where most motor elements contribute to any type of eye movement, although within preferential dynamic ranges, suggesting that signal transmission and muscle contractions occur within bands of frequency-selective pathways.
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Affiliation(s)
- Anja K E Horn
- Institute of Anatomy and Cell Biology I, Ludwig-Maximilians-University Munich, 80336 Munich, Germany;
| | - Hans Straka
- Department Biology II, Ludwig-Maximilians-University Munich, 82152 Planegg, Germany
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14
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Mayadali ÜS, Fleuriet J, Mustari M, Straka H, Horn AKE. Transmitter and ion channel profiles of neurons in the primate abducens and trochlear nuclei. Brain Struct Funct 2021; 226:2125-2151. [PMID: 34181058 PMCID: PMC8354957 DOI: 10.1007/s00429-021-02315-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/04/2021] [Indexed: 01/28/2023]
Abstract
Extraocular motoneurons initiate dynamically different eye movements, including saccades, smooth pursuit and vestibulo-ocular reflexes. These motoneurons subdivide into two main types based on the structure of the neuro-muscular interface: motoneurons of singly-innervated (SIF), and motoneurons of multiply-innervated muscle fibers (MIF). SIF motoneurons are thought to provoke strong and brief/fast muscle contractions, whereas MIF motoneurons initiate prolonged, slow contractions. While relevant for adequate functionality, transmitter and ion channel profiles associated with the morpho-physiological differences between these motoneuron types, have not been elucidated so far. This prompted us to investigate the expression of voltage-gated potassium, sodium and calcium ion channels (Kv1.1, Kv3.1b, Nav1.6, Cav3.1-3.3, KCC2), the transmitter profiles of their presynaptic terminals (vGlut1 and 2, GlyT2 and GAD) and transmitter receptors (GluR2/3, NMDAR1, GlyR1α) using immunohistochemical analyses of abducens and trochlear motoneurons and of abducens internuclear neurons (INTs) in macaque monkeys. The main findings were: (1) MIF and SIF motoneurons express unique voltage-gated ion channel profiles, respectively, likely accounting for differences in intrinsic membrane properties. (2) Presynaptic glutamatergic synapses utilize vGlut2, but not vGlut1. (3) Trochlear motoneurons receive GABAergic inputs, abducens neurons receive both GABAergic and glycinergic inputs. (4) Synaptic densities differ between MIF and SIF motoneurons, with MIF motoneurons receiving fewer terminals. (5) Glutamatergic receptor subtypes differ between MIF and SIF motoneurons. While NMDAR1 is intensely expressed in INTs, MIF motoneurons lack this receptor subtype entirely. The obtained cell-type-specific transmitter and conductance profiles illuminate the structural substrates responsible for differential contributions of neurons in the abducens and trochlear nuclei to eye movements.
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Affiliation(s)
- Ümit Suat Mayadali
- Institute of Anatomy and Cell Biology, Dept. I, Ludwig-Maximilians-University Munich, Pettenkoferstrasse 11, 80336, Munich, Germany
- Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Jérome Fleuriet
- Washington National Primate Research Center, Department of Ophthalmology, University of Washington Seattle, Seattle, WA, USA
- Intensive Care Unit, Raymond Poincaré Hospital, Assistance Publique-Hôpitaux de Paris, Garches, France
| | - Michael Mustari
- Washington National Primate Research Center, Department of Ophthalmology, University of Washington Seattle, Seattle, WA, USA
| | - Hans Straka
- Department of Biology II, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Anja Kerstin Ellen Horn
- Institute of Anatomy and Cell Biology, Dept. I, Ludwig-Maximilians-University Munich, Pettenkoferstrasse 11, 80336, Munich, Germany.
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15
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Carpenter JC, Lignani G. Gene Editing and Modulation: the Holy Grail for the Genetic Epilepsies? Neurotherapeutics 2021; 18:1515-1523. [PMID: 34235638 PMCID: PMC8608979 DOI: 10.1007/s13311-021-01081-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2021] [Indexed: 02/04/2023] Open
Abstract
Epilepsy is a complex neurological disorder for which there are a large number of monogenic subtypes. Monogenic epilepsies are often severe and disabling, featuring drug-resistant seizures and significant developmental comorbidities. These disorders are potentially amenable to a precision medicine approach, of which genome editing using CRISPR/Cas represents the holy grail. Here we consider mutations in some of the most 'common' rare epilepsy genes and discuss the different CRISPR/Cas approaches that could be taken to cure these disorders. We consider scenarios where CRISPR-mediated gene modulation could serve as an effective therapeutic strategy and discuss whether a single gene corrective approach could hold therapeutic potential in the context of homeostatic compensation in the developing, highly dynamic brain. Despite an incomplete understanding of the mechanisms of the genetic epilepsies and current limitations of gene editing tools, CRISPR-mediated approaches have game-changing potential in the treatment of genetic epilepsy over the next decade.
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Affiliation(s)
- Jenna C Carpenter
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, Queen Square House, London, WC1N 3BG, UK
| | - Gabriele Lignani
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, Queen Square House, London, WC1N 3BG, UK.
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16
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Mazuir E, Richevaux L, Nassar M, Robil N, de la Grange P, Lubetzki C, Fricker D, Sol-Foulon N. Oligodendrocyte Secreted Factors Shape Hippocampal GABAergic Neuron Transcriptome and Physiology. Cereb Cortex 2021; 31:5024-5041. [PMID: 34023893 DOI: 10.1093/cercor/bhab139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 03/26/2021] [Accepted: 04/17/2021] [Indexed: 11/14/2022] Open
Abstract
Oligodendrocytes form myelin for central nervous system axons and release factors which signal to neurons during myelination. Here, we ask how oligodendroglial factors influence hippocampal GABAergic neuron physiology. In mixed hippocampal cultures, GABAergic neurons fired action potentials (APs) of short duration and received high frequencies of excitatory synaptic events. In purified neuronal cultures without glial cells, GABAergic neuron excitability increased and the frequency of synaptic events decreased. These effects were largely reversed by adding oligodendrocyte conditioned medium (OCM). We compared the transcriptomic signature with the electrophysiological phenotype of single neurons in these three culture conditions. Genes expressed by single pyramidal or GABAergic neurons largely conformed to expected cell-type specific patterns. Multiple genes of GABAergic neurons were significantly downregulated by the transition from mixed cultures containing glial cells to purified neuronal cultures. Levels of these genes were restored by the addition of OCM to purified cultures. Clustering genes with similar changes in expression between different culture conditions revealed processes affected by oligodendroglial factors. Enriched genes are linked to roles in synapse assembly, AP generation, and transmembrane ion transport, including of zinc. These results provide new insight into the molecular targets by which oligodendrocytes influence neuron excitability and synaptic function.
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Affiliation(s)
- Elisa Mazuir
- Sorbonne University, Inserm, CNRS, Paris Brain Institute, ICM, Pitié-Salpêtrière Hospital, F-75013 Paris, France
| | | | - Merie Nassar
- Université de Paris, INCC UMR 8002, CNRS, F-75006 Paris
| | | | | | - Catherine Lubetzki
- Sorbonne University, Inserm, CNRS, Paris Brain Institute, ICM, Pitié-Salpêtrière Hospital, F-75013 Paris, France.,Assistance Publique des Hôpitaux de Paris (APHP), Neurology Department, Pitié-Salpêtrière hospital, Paris 75013, France
| | | | - Nathalie Sol-Foulon
- Sorbonne University, Inserm, CNRS, Paris Brain Institute, ICM, Pitié-Salpêtrière Hospital, F-75013 Paris, France
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17
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Carpenter JC, Männikkö R, Heffner C, Heneine J, Sampedro‐Castañeda M, Lignani G, Schorge S. Progressive myoclonus epilepsy KCNC1 variant causes a developmental dendritopathy. Epilepsia 2021; 62:1256-1267. [PMID: 33735526 PMCID: PMC8436768 DOI: 10.1111/epi.16867] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/17/2021] [Accepted: 02/17/2021] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Mutations in KCNC1 can cause severe neurological dysfunction, including intellectual disability, epilepsy, and ataxia. The Arg320His variant, which occurs in the voltage-sensing domain of the channel, causes a highly penetrant and specific form of progressive myoclonus epilepsy with severe ataxia, designated myoclonus epilepsy and ataxia due to potassium channel mutation (MEAK). KCNC1 encodes the voltage-gated potassium channel KV 3.1, a channel that is important for enabling high-frequency firing in interneurons, raising the possibility that MEAK is associated with reduced interneuronal function. METHODS To determine how this variant triggers MEAK, we expressed KV 3.1bR320H in cortical interneurons in vitro and investigated the effects on neuronal function and morphology. We also performed electrophysiological recordings of oocytes expressing KV 3.1b to determine whether the mutation introduces gating pore currents. RESULTS Expression of the KV 3.1bR320H variant profoundly reduced excitability of mature cortical interneurons, and cells expressing these channels were unable to support high-frequency firing. The mutant channel also had an unexpected effect on morphology, severely impairing neurite development and interneuron viability, an effect that could not be rescued by blocking KV 3 channels. Oocyte recordings confirmed that in the adult KV 3.1b isoform, R320H confers a dominant negative loss-of-function effect by slowing channel activation, but does not introduce potentially toxic gating pore currents. SIGNIFICANCE Overall, our data suggest that, in addition to the regulation of high-frequency firing, KV 3.1 channels play a hitherto unrecognized role in neuronal development. MEAK may be described as a developmental dendritopathy.
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Affiliation(s)
- Jenna C. Carpenter
- Department of Clinical and Experimental EpilepsyUniversity College London Queen Square Institute of NeurologyLondonUK
| | - Roope Männikkö
- Department of Neuromuscular DiseasesUniversity College London Queen Square Institute of NeurologyLondonUK
| | - Catherine Heffner
- Department of Clinical and Experimental EpilepsyUniversity College London Queen Square Institute of NeurologyLondonUK
| | - Jana Heneine
- Department of Clinical and Experimental EpilepsyUniversity College London Queen Square Institute of NeurologyLondonUK
| | - Marisol Sampedro‐Castañeda
- Department of Clinical and Experimental EpilepsyUniversity College London Queen Square Institute of NeurologyLondonUK
| | - Gabriele Lignani
- Department of Clinical and Experimental EpilepsyUniversity College London Queen Square Institute of NeurologyLondonUK
| | - Stephanie Schorge
- Department of PharmacologyUniversity College London School of PharmacyLondonUK
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18
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Choudhury N, Linley D, Richardson A, Anderson M, Robinson SW, Marra V, Ciampani V, Walter SM, Kopp‐Scheinpflug C, Steinert JR, Forsythe ID. Kv3.1 and Kv3.3 subunits differentially contribute to Kv3 channels and action potential repolarization in principal neurons of the auditory brainstem. J Physiol 2020; 598:2199-2222. [DOI: 10.1113/jp279668] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 03/25/2020] [Indexed: 12/13/2022] Open
Affiliation(s)
- Nasreen Choudhury
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Deborah Linley
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Amy Richardson
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Michelle Anderson
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Susan W. Robinson
- Neurotoxicity at the Synaptic Interface MRC Toxicology Unit University of Leicester, UK
| | - Vincenzo Marra
- Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Victoria Ciampani
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Sophie M. Walter
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Conny Kopp‐Scheinpflug
- Division of Neurobiology Department Biology II Ludwig‐Maximilians‐University Munich Großhaderner Strasse 2 Planegg‐Martinsried D‐82152 Germany
| | - Joern R. Steinert
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
| | - Ian D. Forsythe
- Auditory Neurophysiology Laboratory, Department of Neuroscience Psychology & Behaviour College of Life Sciences University of Leicester Leicester LE1 7RH UK
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19
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Rice J, Coutellier L, Weiner JL, Gu C. Region-specific interneuron demyelination and heightened anxiety-like behavior induced by adolescent binge alcohol treatment. Acta Neuropathol Commun 2019; 7:173. [PMID: 31703603 DOI: 10.1186/s40478-019-0829-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/13/2019] [Indexed: 12/12/2022] Open
Abstract
Adolescent binge drinking represents a major public health challenge and can lead to persistent neurological and mental conditions, but the underlying pathogenic mechanisms remain poorly understood. Using a mouse model of adolescent binge ethanol treatment (ABET), we found that this treatment induced behavioral changes associated with demyelination in different brain regions. After ABET, adolescent mice exhibited anxiogenic behaviors with no change in locomotion on the elevated plus maze, and impaired spatial memory indicated by a significant reduction in spontaneous alternation in the Y maze test. Both effects persisted into adulthood. Anatomical studies further showed that ABET induced a significant reduction of parvalbumin-positive (PV+) GABAergic interneurons and myelin density in the hippocampus and medial prefrontal cortex (mPFC). While these deficits in PV+ interneurons and myelin persisted into early adulthood in the hippocampus, the myelin density recovered in the mPFC. Moreover, whereas ABET mainly damaged myelin of PV+ axons in the hippocampus, it primarily damaged myelin of PV-negative axons in the mPFC. Thus, our findings reveal that an adolescent binge alcohol treatment regimen disrupts spatial working memory, increases anxiety-like behaviors, and exerts unique temporal and spatial patterns of gray matter demyelination in the hippocampus and mPFC.
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20
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Higgs MH, Wilson CJ. Frequency-dependent entrainment of striatal fast-spiking interneurons. J Neurophysiol 2019; 122:1060-1072. [PMID: 31314645 DOI: 10.1152/jn.00369.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Striatal fast-spiking interneurons (FSIs) fire in variable-length runs of action potentials at 20-200 spikes/s separated by pauses. In vivo, or with fluctuating applied current, both runs and pauses become briefer and more variable. During runs, spikes are entrained specifically to gamma-frequency components of the input fluctuations. We stimulated parvalbumin-expressing striatal FSIs in mouse brain slices with broadband noise currents added to direct current steps and measured spike entrainment across all frequencies. As the constant current level was increased, FSIs produced longer runs and showed sharper frequency tuning, with best entrainment at the stimulus frequency matching their intrarun firing rate. We separated the contributions of previous spikes from that of the fluctuating stimulus, revealing a strong contribution of previous action potentials to gamma-frequency entrainment. In contrast, after subtraction of the effect inherited from the previous spike, the remaining stimulus contribution to spike generation was less sharply tuned, showing a larger contribution of lower frequencies. The frequency specificity of entrainment within a run was reproduced with a phase resetting model based on experimentally measured phase resetting curves of the same FSIs. In the model, broadly tuned phase entrainment for the first spike in a run evolved into sharply tuned gamma entrainment over the next few spikes. The data and modeling results indicate that for FSIs firing in brief runs and pauses firing within runs is entrained by gamma-frequency components of the input, whereas the onset timing of runs may be sensitive to a wider range of stimulus frequency components.NEW & NOTEWORTHY Specific types of neurons entrain their spikes to particular oscillation frequencies in their synaptic input. This entrainment is commonly understood in terms of the subthreshold voltage response, but how this translates to spiking is not clear. We show that in striatal fast-spiking interneurons, entrainment to gamma-frequency input depends on rhythmic spike runs and is explained by the phase resetting curve, whereas run initiation can be triggered by a broad range of input frequencies.
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Affiliation(s)
- Matthew H Higgs
- Department of Biology, The University of Texas at San Antonio, San Antonio, Texas
| | - Charles J Wilson
- Department of Biology, The University of Texas at San Antonio, San Antonio, Texas
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