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Nogueira M, Ferreira Golbert DC, Menezes R, Nóbrega de Almeida R, Galvão-Coelho NL, Siroky AN, Lima TZ, Maia H, Leão KE, Leão RN. Serotonergic psychedelic 5-MeO-DMT alters plasticity-related gene expression and generates anxiolytic effects in stressed mice. Mol Psychiatry 2024:10.1038/s41380-024-02655-w. [PMID: 38969716 DOI: 10.1038/s41380-024-02655-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 06/21/2024] [Accepted: 06/27/2024] [Indexed: 07/07/2024]
Abstract
Serotonergic psychedelics have potential therapeutic effects in treating anxiety and mood disorders, often after a single dose, and are suggested to have plasticity-inducing action. However, a comprehensive mechanism of action is still lacking. Here, we investigated how a single dose of the short-acting 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) acts on gene expression from microdissected brain regions (anterior cingulate cortex - ACC; basolateral amygdala - BLA; ventral hippocampus CA1 region - vCA1 and dentate gyrus-DG) of naive and stressed mice. Specifically, we compared gene expression of Arc, Zif268, BDNF, CREB, mTORC1, NR2A, TRIP8b, and NFkB in mice injected with 5-MeO-DMT or saline at different time points (1 h, 5 h, or 5 days prior). 5-MeO-DMT altered mRNA expression of immediate early genes Arc and ZiF268 in the ACC, BLA, and vCA1, while NR2A expression was decreased after 5 h in the vCA1. We also found a long-term increase in TRIP8b, a gene related to the modulation of neuronal activity, in the vCA1 after 5 days. Behaviorally, 5-MeO-DMT treated mice showed mixed anxiolytic and anxiogenic effects in the elevated plus maze and open field test 24 h or 5 days after treatment. However, pre-treated mice subjected to acute stress showed both lower corticosterone levels and robust anxiolytic effects of 5-MeO-DMT administration. Together, our findings provide insights into the molecular actions of 5-MeO-DMT in the brain related to anxiolytic effects of behavior.
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Affiliation(s)
- Margareth Nogueira
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
- Hearing and Neuronal Activity Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Daiane C Ferreira Golbert
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
- Sleep, Dreams and Memory Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Richardson Menezes
- Automation and Robotics Laboratory, School of Science and Technology, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Raíssa Nóbrega de Almeida
- Laboratory of Hormone Measurement, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Nicole L Galvão-Coelho
- Laboratory of Hormone Measurement, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Andressa N Siroky
- Department of Statistics, Exact and Earth Sciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Thiago Z Lima
- Hearing and Neuronal Activity Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
- Department of Statistics, Exact and Earth Sciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Helton Maia
- Automation and Robotics Laboratory, School of Science and Technology, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Katarina E Leão
- Hearing and Neuronal Activity Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
| | - Richardson N Leão
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
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2
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Lyman KA, Han Y, Robinson AP, Weinberg SE, Fisher DW, Heuermann RJ, Lyman RE, Kim DK, Ludwig A, Chandel NS, Does MD, Miller SD, Chetkovich DM. Characterization of hyperpolarization-activated cyclic nucleotide-gated channels in oligodendrocytes. Front Cell Neurosci 2024; 18:1321682. [PMID: 38469353 PMCID: PMC10925711 DOI: 10.3389/fncel.2024.1321682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 02/08/2024] [Indexed: 03/13/2024] Open
Abstract
Mature oligodendrocytes (OLG) are the myelin-forming cells of the central nervous system. Recent work has shown a dynamic role for these cells in the plasticity of neural circuits, leading to a renewed interest in voltage-sensitive currents in OLG. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and their respective current (Ih) were recently identified in mature OLG and shown to play a role in regulating myelin length. Here we provide a biochemical and electrophysiological characterization of HCN channels in cells of the oligodendrocyte lineage. We observed that mice with a nonsense mutation in the Hcn2 gene (Hcn2ap/ap) have less white matter than their wild type counterparts with fewer OLG and fewer oligodendrocyte progenitor cells (OPCs). Hcn2ap/ap mice have severe motor impairments, although these deficits were not observed in mice with HCN2 conditionally eliminated only in oligodendrocytes (Cnpcre/+; Hcn2F/F). However, Cnpcre/+; Hcn2F/F mice develop motor impairments more rapidly in response to experimental autoimmune encephalomyelitis (EAE). We conclude that HCN2 channels in OLG may play a role in regulating metabolism.
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Affiliation(s)
- Kyle A. Lyman
- Department of Neurology, Massachusetts General Hospital, Boston, MA, United States
| | - Ye Han
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Andrew P. Robinson
- Department of Microbiology-Immunology and Interdepartmental Immunobiology Center, Northwestern University, Chicago, IL, United States
| | - Samuel E. Weinberg
- Department of Medicine, Northwestern University, Chicago, IL, United States
| | - Daniel W. Fisher
- Department of Psychiatry, University of Washington, Seattle, WA, United States
| | - Robert J. Heuermann
- Department of Neurology, Washington University, St. Louis, MO, United States
| | - Reagan E. Lyman
- Heritage College of Osteopathic Medicine, Ohio University, Dublin, OH, United States
| | - Dong Kyu Kim
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, TN, United States
- Department of Electrical Engineering, Vanderbilt University, Nashville, TN, United States
| | - Andreas Ludwig
- Institut fur Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universitat Erlangen-Nurnberg, Erlangen, Germany
| | - Navdeep S. Chandel
- Department of Medicine, Northwestern University, Chicago, IL, United States
| | - Mark D. Does
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States
- Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, TN, United States
- Department of Electrical Engineering, Vanderbilt University, Nashville, TN, United States
| | - Stephen D. Miller
- Department of Microbiology-Immunology and Interdepartmental Immunobiology Center, Northwestern University, Chicago, IL, United States
| | - Dane M. Chetkovich
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States
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3
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Machado JP, Athie MC, Matos AH, Lopes-Cendes I, Vieira A. The transcriptome of rat hippocampal subfields. IBRO Neurosci Rep 2022; 13:322-329. [PMID: 36247526 PMCID: PMC9561749 DOI: 10.1016/j.ibneur.2022.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 11/08/2022] Open
Abstract
The hippocampus comprises several neuronal populations such as CA1, CA2, CA3, and the dentate gyrus (DG), which present different neuronal origins, morphologies, and molecular mechanisms. Laser capture microdissection (LCM) allows selectively collecting samples from target regions and eliminating unwanted cells to obtain more specific results. LCM of hippocampus neuronal populations coupĺed with RNA-seq analysis has the potential to allow the exploration of the molecular machinery unique to each of these subfields. Previous RNA-seq investigation has already provided a molecular blueprint of the hippocampus, however, there is no RNA-seq data specific for each of the rat hippocampal regions. Serial tissue sections covering the hippocampus were produced from frozen brains of adult male Wistar rats, and the hippocampal subfields CA1, CA2, CA3, and DG were identified and isolated by LCM. We found evident segregation of the transcriptomic profile from different regions of the hippocampus and the expression of known, as well as novel, specific marker genes for each region. Gene ontology enrichment analysis of CA1 subfield indicates an enrichment of actin regulation and postsynaptic membrane AMPA receptors genes indispensable for long-term potentiation. CA2 and CA3 transcripts were found associated with the increased metabolic processes. DG expression was enriched for ribosome and spliceosome, both required for protein synthesis and maintenance of cell life. The present findings contribute to a deeper understanding of the differences in the molecular machinery expressed by the rat hippocampal neuronal populations, further exploring underlying mechanisms responsible for each subflied specific functions.
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Affiliation(s)
- João P.D. Machado
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
| | - Maria C.P. Athie
- Department of Translational Medicine, School of Medical Sciences. University of Campinas (UNICAMP), Campinas, São Paulo, Brazil,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
| | - Alexandre H.B. Matos
- Department of Translational Medicine, School of Medical Sciences. University of Campinas (UNICAMP), Campinas, São Paulo, Brazil,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
| | - Iscia Lopes-Cendes
- Department of Translational Medicine, School of Medical Sciences. University of Campinas (UNICAMP), Campinas, São Paulo, Brazil,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil
| | - André.S. Vieira
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, São Paulo, Brazil,Correspondence to: Department of Structural and Functional Biology, Institute of Biology, Cidade Universitária “Zeferino Vaz”, University of Campinas, UNICAMP, Rua Monteiro Lobato, 255 - Bloco J - 1 piso - Sl 16, Campinas 13083-862, São Paulo, Brazil.
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4
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Han Y, Iyamu ID, Clutter MR, Mishra RK, Lyman KA, Zhou C, Michailidis I, Xia MY, Sharma H, Luan CH, Schiltz GE, Chetkovich DM. Discovery of a small-molecule inhibitor of the TRIP8b-HCN interaction with efficacy in neurons. J Biol Chem 2022; 298:102069. [PMID: 35623388 PMCID: PMC9243175 DOI: 10.1016/j.jbc.2022.102069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 05/17/2022] [Accepted: 05/22/2022] [Indexed: 10/27/2022] Open
Abstract
Major depressive disorder is a critical public health problem with a lifetime prevalence of nearly 17% in the United States. One potential therapeutic target is the interaction between hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and an auxiliary subunit of the channel named tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b). HCN channels regulate neuronal excitability in the mammalian hippocampus, and recent work has established that antagonizing HCN function rescues cognitive impairment caused by chronic stress. Here, we utilize a high-throughput virtual screen to find small molecules capable of disrupting the TRIP8b-HCN interaction. We found that the hit compound NUCC-0200590 disrupts the TRIP8b-HCN interaction in vitro and in vivo. These results provide a compelling strategy for developing new small molecules capable of disrupting the TRIP8b-HCN interaction.
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Affiliation(s)
- Ye Han
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Iredia D Iyamu
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois, USA
| | - Matthew R Clutter
- High Throughput Analysis Laboratory and Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA
| | - Rama K Mishra
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois, USA
| | - Kyle A Lyman
- Department of Neurology, Stanford University, Palo Alto, California, USA
| | - Chengwen Zhou
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Ioannis Michailidis
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Maya Y Xia
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Horrick Sharma
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois, USA
| | - Chi-Hao Luan
- High Throughput Analysis Laboratory and Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA; Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Gary E Schiltz
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA; Department of Pharmacology, Northwestern University, Chicago, Illinois, USA; Department of Chemistry, Northwestern University, Evanston, Illinois, USA.
| | - Dane M Chetkovich
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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5
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Peters CH, Singh RK, Bankston JR, Proenza C. Regulation of HCN Channels by Protein Interactions. Front Physiol 2022; 13:928507. [PMID: 35795651 PMCID: PMC9251338 DOI: 10.3389/fphys.2022.928507] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/01/2022] [Indexed: 11/30/2022] Open
Abstract
Hyperpolarization-activated, cyclic nucleotide-sensitive (HCN) channels are key regulators of subthreshold membrane potentials in excitable cells. The four mammalian HCN channel isoforms, HCN1-HCN4, are expressed throughout the body, where they contribute to diverse physiological processes including cardiac pacemaking, sleep-wakefulness cycles, memory, and somatic sensation. While all HCN channel isoforms produce currents when expressed by themselves, an emerging list of interacting proteins shape HCN channel excitability to influence the physiologically relevant output. The best studied of these regulatory proteins is the auxiliary subunit, TRIP8b, which binds to multiple sites in the C-terminus of the HCN channels to regulate expression and disrupt cAMP binding to fine-tune neuronal HCN channel excitability. Less is known about the mechanisms of action of other HCN channel interaction partners like filamin A, Src tyrosine kinase, and MinK-related peptides, which have a range of effects on HCN channel gating and expression. More recently, the inositol trisphosphate receptor-associated cGMP-kinase substrates IRAG1 and LRMP (also known as IRAG2), were discovered as specific regulators of the HCN4 isoform. This review summarizes the known protein interaction partners of HCN channels and their mechanisms of action and identifies gaps in our knowledge.
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Affiliation(s)
- Colin H. Peters
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Rohit K. Singh
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - John R. Bankston
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Catherine Proenza
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Cardiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- *Correspondence: Catherine Proenza,
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6
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Lankford C, Houtman J, Baker SA. Identification of HCN1 as a 14-3-3 client. PLoS One 2022; 17:e0268335. [PMID: 35679272 PMCID: PMC9182292 DOI: 10.1371/journal.pone.0268335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 04/28/2022] [Indexed: 11/19/2022] Open
Abstract
Hyperpolarization activated cyclic nucleotide-gated channel 1 (HCN1) is expressed throughout the nervous system and is critical for regulating neuronal excitability, with mutations being associated with multiple forms of epilepsy. Adaptive modulation of HCN1 has been observed, as has pathogenic dysregulation. While the mechanisms underlying this modulation remain incompletely understood, regulation of HCN1 has been shown to include phosphorylation. A candidate phosphorylation-dependent regulator of HCN1 channels is 14-3-3. We used bioinformatics to identify three potential 14-3-3 binding sites in HCN1. We confirmed that 14-3-3 could pull down HCN1 from multiple tissue sources and used HEK293 cells to detail the interaction. Two sites in the intrinsically disordered C-terminus of HCN1 were necessary and sufficient for a phosphorylation-dependent interaction with 14-3-3. The same region of HCN1 containing the 14-3-3 binding peptides is required for phosphorylation-independent protein degradation. We propose a model in which phosphorylation of mouse S810 and S867 (human S789 and S846) recruits 14-3-3 to inhibit a yet unidentified factor signaling for protein degradation, thus increasing the half-life of HCN1.
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Affiliation(s)
- Colten Lankford
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, Iowa, United States of America
| | - Jon Houtman
- Department of Microbiology and Immunology, University of Iowa, Iowa City, Iowa, United States of America
| | - Sheila A. Baker
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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7
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Lyman KA, Han Y, Zhou C, Renteria I, Besing GL, Kurz JE, Chetkovich DM. Hippocampal cAMP regulates HCN channel function on two time scales with differential effects on animal behavior. Sci Transl Med 2021; 13:eabl4580. [PMID: 34818058 DOI: 10.1126/scitranslmed.abl4580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Kyle A Lyman
- Department of Neurology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave., Chicago, IL 60611, USA.,Department of Neurology, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN 37232, USA.,Department of Neurology, Stanford University, 453 Quarry Road, Palo Alto, CA 94304, USA
| | - Ye Han
- Department of Neurology, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN 37232, USA
| | - Chengwen Zhou
- Department of Neurology, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN 37232, USA
| | - Isabelle Renteria
- Department of Neurology, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN 37232, USA
| | - Gai-Linn Besing
- Department of Neurology, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN 37232, USA
| | - Jonathan E Kurz
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, 225 E. Chicago Ave., Chicago, IL 60611, USA
| | - Dane M Chetkovich
- Department of Neurology, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN 37232, USA
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8
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Blockus H, Rolotti SV, Szoboszlay M, Peze-Heidsieck E, Ming T, Schroeder A, Apostolo N, Vennekens KM, Katsamba PS, Bahna F, Mannepalli S, Ahlsen G, Honig B, Shapiro L, de Wit J, Losonczy A, Polleux F. Synaptogenic activity of the axon guidance molecule Robo2 underlies hippocampal circuit function. Cell Rep 2021; 37:109828. [PMID: 34686348 PMCID: PMC8605498 DOI: 10.1016/j.celrep.2021.109828] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 07/06/2021] [Accepted: 09/22/2021] [Indexed: 01/03/2023] Open
Abstract
Synaptic connectivity within adult circuits exhibits a remarkable degree of cellular and subcellular specificity. We report that the axon guidance receptor Robo2 plays a role in establishing synaptic specificity in hippocampal CA1. In vivo, Robo2 is present and required postsynaptically in CA1 pyramidal neurons (PNs) for the formation of excitatory (E) but not inhibitory (I) synapses, specifically in proximal but not distal dendritic compartments. In vitro approaches show that the synaptogenic activity of Robo2 involves a trans-synaptic interaction with presynaptic Neurexins, as well as binding to its canonical extracellular ligand Slit. In vivo 2-photon Ca2+ imaging of CA1 PNs during spatial navigation in awake behaving mice shows that preventing Robo2-dependent excitatory synapse formation cell autonomously during development alters place cell properties of adult CA1 PNs. Our results identify a trans-synaptic complex linking the establishment of synaptic specificity to circuit function.
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Affiliation(s)
- Heike Blockus
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Sebi V Rolotti
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Miklos Szoboszlay
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Eugénie Peze-Heidsieck
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Tiffany Ming
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Anna Schroeder
- VIB Center for Brain and Disease Research, Herestraat 49, 3000 Leuven, Belgium; Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Nuno Apostolo
- VIB Center for Brain and Disease Research, Herestraat 49, 3000 Leuven, Belgium; Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Kristel M Vennekens
- VIB Center for Brain and Disease Research, Herestraat 49, 3000 Leuven, Belgium; Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Phinikoula S Katsamba
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Fabiana Bahna
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Seetha Mannepalli
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Goran Ahlsen
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Barry Honig
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Lawrence Shapiro
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Joris de Wit
- VIB Center for Brain and Disease Research, Herestraat 49, 3000 Leuven, Belgium; Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Attila Losonczy
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA.
| | - Franck Polleux
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA.
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9
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Park J, Farris S. Spatiotemporal Regulation of Transcript Isoform Expression in the Hippocampus. Front Mol Neurosci 2021; 14:694234. [PMID: 34305526 PMCID: PMC8295539 DOI: 10.3389/fnmol.2021.694234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/15/2021] [Indexed: 11/13/2022] Open
Abstract
Proper development and plasticity of hippocampal neurons require specific RNA isoforms to be expressed in the right place at the right time. Precise spatiotemporal transcript regulation requires the incorporation of essential regulatory RNA sequences into expressed isoforms. In this review, we describe several RNA processing strategies utilized by hippocampal neurons to regulate the spatiotemporal expression of genes critical to development and plasticity. The works described here demonstrate how the hippocampus is an ideal investigative model for uncovering alternate isoform-specific mechanisms that restrict the expression of transcripts in space and time.
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Affiliation(s)
- Joun Park
- Fralin Biomedical Research Institute, Center for Neurobiology Research, Virginia Tech Carilion, Roanoke, VA, United States
| | - Shannon Farris
- Fralin Biomedical Research Institute, Center for Neurobiology Research, Virginia Tech Carilion, Roanoke, VA, United States.,Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States.,Virginia Tech Carilion School of Medicine, Roanoke, VA, United States
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10
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Characterization of the HCN Interaction Partner TRIP8b/PEX5R in the Intracardiac Nervous System of TRIP8b-Deficient and Wild-Type Mice. Int J Mol Sci 2021; 22:ijms22094772. [PMID: 33946275 PMCID: PMC8125662 DOI: 10.3390/ijms22094772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/21/2021] [Accepted: 04/28/2021] [Indexed: 12/25/2022] Open
Abstract
The tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b/PEX5R) is an interaction partner and auxiliary subunit of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which are key for rhythm generation in the brain and in the heart. Since TRIP8b is expressed in central neurons but not in cardiomyocytes, the TRIP8b-HCN interaction has been studied intensely in the brain, but is deemed irrelevant in the cardiac conduction system. Still, to date, TRIP8b has not been studied in the intrinsic cardiac nervous system (ICNS), a neuronal network located within epicardial fat pads. In vitro electrophysiological studies revealed that TRIP8b-deficient mouse hearts exhibit increased atrial refractory and atrioventricular nodal refractory periods, compared to hearts of wild-type littermates. Meanwhile, heart rate, sino-nodal recovery time, and ventricular refractory period did not differ between genotypes. Trip8b mRNA was detected in the ICNS by quantitative polymerase chain reaction. RNAscope in situ hybridization confirmed Trip8b localization in neuronal somata and nerve fibers. Additionally, we found a very low amount of mRNAs in the sinus node and atrioventricular node, most likely attributable to the delicate fibers innervating the conduction system. In contrast, TRIP8b protein was not detectable. Our data suggest that TRIP8b in the ICNS may play a role in the modulation of atrial electrophysiology beyond HCN-mediated sino-nodal control of the heart.
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11
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Homeostatic plasticity and burst activity are mediated by hyperpolarization-activated cation currents and T-type calcium channels in neuronal cultures. Sci Rep 2021; 11:3236. [PMID: 33547341 PMCID: PMC7864958 DOI: 10.1038/s41598-021-82775-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 01/20/2021] [Indexed: 01/27/2023] Open
Abstract
Homeostatic plasticity stabilizes neuronal networks by adjusting the responsiveness of neurons according to their global activity and the intensity of the synaptic inputs. We investigated the homeostatic regulation of hyperpolarization-activated cyclic nucleotide-gated (HCN) and T-type calcium (CaV3) channels in dissociated and organotypic slice cultures. After 48 h blocking of neuronal activity by tetrodotoxin (TTX), our patch-clamp experiments revealed an increase in the depolarizing voltage sag and post-inhibitory rebound mediated by HCN and CaV3 channels, respectively. All HCN subunits (HCN1 to 4) and T-type Ca-channel subunits (CaV3.1, 3.2 and 3.3) were expressed in both control and activity-deprived hippocampal cultures. Elevated expression levels of CaV3.1 mRNA and a selective increase in the expression of TRIP8b exon 4 isoforms, known to regulate HCN channel localization, were also detected in TTX-treated cultured hippocampal neurons. Immunohistochemical staining in TTX-treated organotypic slices verified a more proximal translocation of HCN1 channels in CA1 pyramidal neurons. Computational modeling also implied that HCN and T-type calcium channels have important role in the regulation of synchronized bursting evoked by previous activity-deprivation. Thus, our findings indicate that HCN and T-type Ca-channels contribute to the homeostatic regulation of excitability and integrative properties of hippocampal neurons.
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12
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Disruption of NEUROD2 causes a neurodevelopmental syndrome with autistic features via cell-autonomous defects in forebrain glutamatergic neurons. Mol Psychiatry 2021; 26:6125-6148. [PMID: 34188164 PMCID: PMC8760061 DOI: 10.1038/s41380-021-01179-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 05/17/2021] [Accepted: 05/26/2021] [Indexed: 02/06/2023]
Abstract
While the transcription factor NEUROD2 has recently been associated with epilepsy, its precise role during nervous system development remains unclear. Using a multi-scale approach, we set out to understand how Neurod2 deletion affects the development of the cerebral cortex in mice. In Neurod2 KO embryos, cortical projection neurons over-migrated, thereby altering the final size and position of layers. In juvenile and adults, spine density and turnover were dysregulated in apical but not basal compartments in layer 5 neurons. Patch-clamp recordings in layer 5 neurons of juvenile mice revealed increased intrinsic excitability. Bulk RNA sequencing showed dysregulated expression of many genes associated with neuronal excitability and synaptic function, whose human orthologs were strongly associated with autism spectrum disorders (ASD). At the behavior level, Neurod2 KO mice displayed social interaction deficits, stereotypies, hyperactivity, and occasionally spontaneous seizures. Mice heterozygous for Neurod2 had similar defects, indicating that Neurod2 is haploinsufficient. Finally, specific deletion of Neurod2 in forebrain excitatory neurons recapitulated cellular and behavioral phenotypes found in constitutive KO mice, revealing the region-specific contribution of dysfunctional Neurod2 in symptoms. Informed by these neurobehavioral features in mouse mutants, we identified eleven patients from eight families with a neurodevelopmental disorder including intellectual disability and ASD associated with NEUROD2 pathogenic mutations. Our findings demonstrate crucial roles for Neurod2 in neocortical development, whose alterations can cause neurodevelopmental disorders including intellectual disability and ASD.
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13
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Han Y, Lyman KA, Foote KM, Chetkovich DM. The structure and function of TRIP8b, an auxiliary subunit of hyperpolarization-activated cyclic-nucleotide gated channels. Channels (Austin) 2020; 14:110-122. [PMID: 32189562 PMCID: PMC7153792 DOI: 10.1080/19336950.2020.1740501] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/18/2020] [Accepted: 02/21/2020] [Indexed: 02/08/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are expressed throughout the mammalian central nervous system (CNS). These channels have been implicated in a wide range of diseases, including Major Depressive Disorder and multiple subtypes of epilepsy. The diversity of functions that HCN channels perform is in part attributable to differences in their subcellular localization. To facilitate a broad range of subcellular distributions, HCN channels are bound by auxiliary subunits that regulate surface trafficking and channel function. One of the best studied auxiliary subunits is tetratricopeptide-repeat containing, Rab8b-interacting protein (TRIP8b). TRIP8b is an extensively alternatively spliced protein whose only known function is to regulate HCN channels. TRIP8b binds to HCN pore-forming subunits at multiple interaction sites that differentially regulate HCN channel function and subcellular distribution. In this review, we summarize what is currently known about the structure and function of TRIP8b isoforms with an emphasis on the role of this auxiliary subunit in health and disease.
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Affiliation(s)
- Ye Han
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kyle A. Lyman
- Department of Neurology, Stanford University, Palo Alto, CA, USA
| | - Kendall M. Foote
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Dane M. Chetkovich
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
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14
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Santoro B, Shah MM. Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels as Drug Targets for Neurological Disorders. Annu Rev Pharmacol Toxicol 2020; 60:109-131. [PMID: 31914897 DOI: 10.1146/annurev-pharmtox-010919-023356] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are voltage-gated ion channels that critically modulate neuronal activity. Four HCN subunits (HCN1-4) have been cloned, each having a unique expression profile and distinctive effects on neuronal excitability within the brain. Consistent with this, the expression and function of these subunits are altered in diverse ways in neurological disorders. Here, we review current knowledge on the structure and distribution of the individual HCN channel isoforms, their effects on neuronal activity under physiological conditions, and how their expression and function are altered in neurological disorders, particularly epilepsy, neuropathic pain, and affective disorders. We discuss the suitability of HCN channels as therapeutic targets and how drugs might be strategically designed to specifically act on particular isoforms. We conclude that medicines that target individual HCN isoforms and/or their auxiliary subunit, TRIP8b, may provide valuable means of treating distinct neurological conditions.
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Affiliation(s)
- Bina Santoro
- Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Mala M Shah
- Department of Pharmacology, School of Pharmacy, University College London, London WC1N 1AX, United Kingdom;
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15
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Porro A, Binda A, Pisoni M, Donadoni C, Rivolta I, Saponaro A. Rational design of a mutation to investigate the role of the brain protein TRIP8b in limiting the cAMP response of HCN channels in neurons. J Gen Physiol 2020; 152:e202012596. [PMID: 32633755 PMCID: PMC7478871 DOI: 10.1085/jgp.202012596] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/02/2020] [Accepted: 06/08/2020] [Indexed: 01/22/2023] Open
Abstract
TRIP8b (tetratricopeptide repeat-containing Rab8b-interacting protein) is the neuronal regulatory subunit of HCN channels, a family of voltage-dependent cation channels also modulated by direct cAMP binding. TRIP8b interacts with the C-terminal region of HCN channels and controls both channel trafficking and gating. The association of HCN channels with TRIP8b is required for the correct expression and subcellular targeting of the channel protein in vivo. TRIP8b controls HCN gating by interacting with the cyclic nucleotide-binding domain (CNBD) and competing for cAMP binding. Detailed structural knowledge of the complex between TRIP8b and CNBD was used as a starting point to engineer a mutant channel, whose gating is controlled by cAMP, but not by TRIP8b, while leaving TRIP8b-dependent regulation of channel trafficking unaltered. We found two-point mutations (N/A and C/D) in the loop connecting the CNBD to the C-linker (N-bundle loop) that, when combined, strongly reduce the binding of TRIP8b to CNBD, leaving cAMP affinity unaltered both in isolated CNBD and in the full-length protein. Proof-of-principle experiments performed in cultured cortical neurons confirm that the mutant channel provides a genetic tool for dissecting the two effects of TRIP8b (gating versus trafficking). This will allow the study of the functional role of the TRIP8b antagonism of cAMP binding, a thus far poorly investigated aspect of HCN physiology in neurons.
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Affiliation(s)
| | - Anna Binda
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | | | - Chiara Donadoni
- Department of Biosciences, University of Milano, Milano, Italy
| | - Ilaria Rivolta
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Andrea Saponaro
- Department of Biosciences, University of Milano, Milano, Italy
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16
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Choi SJ, Ma TC, Ding Y, Cheung T, Joshi N, Sulzer D, Mosharov EV, Kang UJ. Alterations in the intrinsic properties of striatal cholinergic interneurons after dopamine lesion and chronic L-DOPA. eLife 2020; 9:56920. [PMID: 32687053 PMCID: PMC7380940 DOI: 10.7554/elife.56920] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 07/17/2020] [Indexed: 12/21/2022] Open
Abstract
Changes in striatal cholinergic interneuron (ChI) activity are thought to contribute to Parkinson's disease pathophysiology and dyskinesia from chronic L-3,4-dihydroxyphenylalanine (L-DOPA) treatment, but the physiological basis of these changes is unknown. We find that dopamine lesion decreases the spontaneous firing rate of ChIs, whereas chronic treatment with L-DOPA of lesioned mice increases baseline ChI firing rates to levels beyond normal activity. The effect of dopamine loss on ChIs was due to decreased currents of both hyperpolarization-activated cyclic nucleotide-gated (HCN) and small conductance calcium-activated potassium (SK) channels. L-DOPA reinstatement of dopamine normalized HCN activity, but SK current remained depressed. Pharmacological blockade of HCN and SK activities mimicked changes in firing, confirming that these channels are responsible for the molecular adaptation of ChIs to dopamine loss and chronic L-DOPA treatment. These findings suggest that targeting ChIs with channel-specific modulators may provide therapeutic approaches for alleviating L-DOPA-induced dyskinesia in PD patients.
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Affiliation(s)
- Se Joon Choi
- Department of Psychiatry, Columbia University Medical Center, New York, United States
| | - Thong C Ma
- Department of Neurology, Grossman School of Medicine, New York University, New York, United States
| | - Yunmin Ding
- Department of Neurology, Grossman School of Medicine, New York University, New York, United States
| | - Timothy Cheung
- Department of Neurology, Grossman School of Medicine, New York University, New York, United States
| | - Neal Joshi
- Department of Neurology, Grossman School of Medicine, New York University, New York, United States
| | - David Sulzer
- Department of Psychiatry, Columbia University Medical Center, New York, United States
| | - Eugene V Mosharov
- Department of Psychiatry, Columbia University Medical Center, New York, United States
| | - Un Jung Kang
- Department of Neurology, Grossman School of Medicine, New York University, New York, United States
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17
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Forster LA, Jansen LAR, Rubaharan M, Murphy AZ, Baro DJ. Alterations in SUMOylation of the hyperpolarization-activated cyclic nucleotide-gated ion channel 2 during persistent inflammation. Eur J Pain 2020; 24:1517-1536. [PMID: 32446289 PMCID: PMC7496191 DOI: 10.1002/ejp.1606] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/28/2020] [Accepted: 05/15/2020] [Indexed: 01/08/2023]
Abstract
Background Unilateral injection of Complete Freund's Adjuvant (CFA) into the intra‐plantar surface of the rodent hindpaw elicits chronic inflammation and hyperalgesia in the ipsilateral hindlimb. Mechanisms contributing to this hyperalgesia may act over multiple time courses and can include changes in ion channel expression and post‐translational SUMOylation. Hyperpolarization‐activated, cyclic nucleotide‐gated (HCN) channels mediate the hyperpolarization‐activated current, Ih. An HCN2‐mediated increase in C‐nociceptor Ih contributes to mechanical hyperalgesia in the CFA model of inflammatory pain. Changes in HCN2 post‐translational SUMOylation and protein expression have not been systematically documented for a given dorsal root ganglia (DRG) throughout the time course of inflammation. Methods This study examined HCN2 protein expression and post‐translational SUMOylation in a rat model of CFA‐induced hindpaw inflammation. L5 DRG cryosections were used in immunohistochemistry experiments and proximity ligation assays to investigate HCN2 expression and SUMOylation, respectively, on days 1 and 3 post‐CFA. Results Unilateral CFA injection elicited a significant bilateral increase in HCN2 staining intensity in small diameter DRG neurons on day 1 post‐CFA, and a significant bilateral increase in the number of small neurons expressing HCN2 but not staining intensity on day 3 post‐CFA. HCN2 channels were hyper‐SUMOylated in small diameter neurons of ipsilateral relative to contralateral DRG on days 1 and 3 post‐CFA. Conclusions Unilateral CFA injection elicits unilateral mechanical hyperalgesia, a bilateral increase in HCN2 expression and a unilateral increase in post‐translational SUMOylation. This suggests that enhanced HCN2 expression in L5 DRG is not sufficient for mechanical hyperalgesia in the early stages of inflammation and that hyper‐SUMOylation of HCN2 channels may also be necessary. Significance Nociceptor HCN2 channels mediate an increase in Ih that is necessary for mechanical hyperalgesia in a CFA model of chronic pain, but the mechanisms producing the increase in nociceptor Ih have not been resolved. The data presented here suggest that the increase in Ih during the early stages of inflammation may be mediated by an increase in HCN2 protein expression and post‐translational SUMOylation.
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Affiliation(s)
- Lori A Forster
- Department of Biology, Georgia State University, Atlanta, GA, USA.,Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | | | | | - Anne Z Murphy
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | - Deborah J Baro
- Department of Biology, Georgia State University, Atlanta, GA, USA.,Neuroscience Institute, Georgia State University, Atlanta, GA, USA
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18
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Rivolta I, Binda A, Masi A, DiFrancesco JC. Cardiac and neuronal HCN channelopathies. Pflugers Arch 2020; 472:931-951. [PMID: 32424620 DOI: 10.1007/s00424-020-02384-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/21/2020] [Accepted: 04/24/2020] [Indexed: 12/31/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are expressed as four different isoforms (HCN1-4) in the heart and in the central and peripheral nervous systems. In the voltage range of activation, HCN channels carry an inward current mediated by Na+ and K+, termed If in the heart and Ih in neurons. Altered function of HCN channels, mainly HCN4, is associated with sinus node dysfunction and other arrhythmias such as atrial fibrillation, ventricular tachycardia, and atrioventricular block. In recent years, several data have also shown that dysfunctional HCN channels, in particular HCN1, but also HCN2 and HCN4, can play a pathogenic role in epilepsy; these include experimental data from animal models, and data collected over genetic mutations of the channels identified and characterized in epileptic patients. In the central nervous system, alteration of the Ih current could predispose to the development of neurodegenerative diseases such as Parkinson's disease; since HCN channels are widely expressed in the peripheral nervous system, their dysfunctional behavior could also be associated with the pathogenesis of neuropathic pain. Given the fundamental role played by the HCN channels in the regulation of the discharge activity of cardiac and neuronal cells, the modulation of their function for therapeutic purposes is under study since it could be useful in various pathological conditions. Here we review the present knowledge of the HCN-related channelopathies in cardiac and neurological diseases, including clinical, genetic, therapeutic, and physiopathological aspects.
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Affiliation(s)
- Ilaria Rivolta
- School of Medicine and Surgery, Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Monza, Italy
| | - Anna Binda
- School of Medicine and Surgery, Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Monza, Italy
| | - Alessio Masi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Jacopo C DiFrancesco
- School of Medicine and Surgery, Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Monza, Italy. .,Department of Neurology, ASST San Gerardo Hospital, University of Milano-Bicocca, Via Pergolesi, 33, 20900, Monza, MB, Italy.
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19
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Cingolani LA, Vitale C, Dityatev A. Intra- and Extracellular Pillars of a Unifying Framework for Homeostatic Plasticity: A Crosstalk Between Metabotropic Receptors and Extracellular Matrix. Front Cell Neurosci 2019; 13:513. [PMID: 31803023 PMCID: PMC6877475 DOI: 10.3389/fncel.2019.00513] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 10/29/2019] [Indexed: 11/18/2022] Open
Abstract
In the face of chronic changes in incoming sensory inputs, neuronal networks are capable of maintaining stable conditions of electrical activity over prolonged periods of time by adjusting synaptic strength, to amplify or dampen incoming inputs [homeostatic synaptic plasticity (HSP)], or by altering the intrinsic excitability of individual neurons [homeostatic intrinsic plasticity (HIP)]. Emerging evidence suggests a synergistic interplay between extracellular matrix (ECM) and metabotropic receptors in both forms of homeostatic plasticity. Activation of dopaminergic, serotonergic, or glutamate metabotropic receptors stimulates intracellular signaling through calmodulin-dependent protein kinase II, protein kinase A, protein kinase C, and inositol trisphosphate receptors, and induces changes in expression of ECM molecules and proteolysis of both ECM molecules (lecticans) and ECM receptors (NPR, CD44). The resulting remodeling of perisynaptic and synaptic ECM provides permissive conditions for HSP and plays an instructive role by recruiting additional signaling cascades, such as those through metabotropic glutamate receptors and integrins. The superimposition of all these signaling events determines intracellular and diffusional trafficking of ionotropic glutamate receptors, resulting in HSP and modulation of conditions for inducing Hebbian synaptic plasticity (i.e., metaplasticity). It also controls cell-surface delivery and activity of voltage- and Ca2+-gated ion channels, resulting in HIP. These mechanisms may modify epileptogenesis and become a target for therapeutic interventions.
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Affiliation(s)
- Lorenzo A. Cingolani
- Department of Life Sciences, University of Trieste, Trieste, Italy
- Center for Synaptic Neuroscience and Technology (NSYN), Istituto Italiano di Tecnologia, Genoa, Italy
| | - Carmela Vitale
- Center for Synaptic Neuroscience and Technology (NSYN), Istituto Italiano di Tecnologia, Genoa, Italy
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Alexander Dityatev
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
- Medical Faculty, Otto von Guericke University Magdeburg, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
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20
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Foote KM, Lyman KA, Han Y, Michailidis IE, Heuermann RJ, Mandikian D, Trimmer JS, Swanson GT, Chetkovich DM. Phosphorylation of the HCN channel auxiliary subunit TRIP8b is altered in an animal model of temporal lobe epilepsy and modulates channel function. J Biol Chem 2019; 294:15743-15758. [PMID: 31492750 DOI: 10.1074/jbc.ra119.010027] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/30/2019] [Indexed: 12/14/2022] Open
Abstract
Temporal lobe epilepsy (TLE) is a prevalent neurological disorder with many patients experiencing poor seizure control with existing anti-epileptic drugs. Thus, novel insights into the mechanisms of epileptogenesis and identification of new drug targets can be transformative. Changes in ion channel function have been shown to play a role in generating the aberrant neuronal activity observed in TLE. Previous work demonstrates that hyperpolarization-activated cyclic nucleotide-gated (HCN) channels regulate neuronal excitability and are mislocalized within CA1 pyramidal cells in a rodent model of TLE. The subcellular distribution of HCN channels is regulated by an auxiliary subunit, tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b), and disruption of this interaction correlates with channel mislocalization. However, the molecular mechanisms responsible for HCN channel dysregulation in TLE are unclear. Here we investigated whether changes in TRIP8b phosphorylation are sufficient to alter HCN channel function. We identified a phosphorylation site at residue Ser237 of TRIP8b that enhances binding to HCN channels and influences channel gating by altering the affinity of TRIP8b for the HCN cytoplasmic domain. Using a phosphospecific antibody, we demonstrate that TRIP8b phosphorylated at Ser237 is enriched in CA1 distal dendrites and that phosphorylation is reduced in the kainic acid model of TLE. Overall, our findings indicate that the TRIP8b-HCN interaction can be modulated by changes in phosphorylation and suggest that loss of TRIP8b phosphorylation may affect HCN channel properties during epileptogenesis. These results highlight the potential of drugs targeting posttranslational modifications to restore TRIP8b phosphorylation to reduce excitability in TLE.
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Affiliation(s)
- Kendall M Foote
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University, Chicago, Illinois 60611.,Department of Pharmacology, Northwestern University, Chicago, Illinois 60611.,Vanderbilt University Medical Center Department of Neurology, Nashville, Tennessee 37232
| | - Kyle A Lyman
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University, Chicago, Illinois 60611.,Vanderbilt University Medical Center Department of Neurology, Nashville, Tennessee 37232.,Department of Medicine, Stanford University, Palo Alto, California 94305
| | - Ye Han
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University, Chicago, Illinois 60611.,Vanderbilt University Medical Center Department of Neurology, Nashville, Tennessee 37232
| | - Ioannis E Michailidis
- Vanderbilt University Medical Center Department of Neurology, Nashville, Tennessee 37232
| | - Robert J Heuermann
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Danielle Mandikian
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California 95616
| | - James S Trimmer
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California 95616.,Department of Physiology and Membrane Biology, University of California, Davis, California 95616
| | - Geoffrey T Swanson
- Department of Pharmacology, Northwestern University, Chicago, Illinois 60611.,Department of Neurobiology, Northwestern University, Evanston, Illinois 60208
| | - Dane M Chetkovich
- Vanderbilt University Medical Center Department of Neurology, Nashville, Tennessee 37232
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21
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Luo P, He G, Liu D. HCN channels: New targets for the design of an antidepressant with rapid effects. J Affect Disord 2019; 245:764-770. [PMID: 30448761 DOI: 10.1016/j.jad.2018.11.081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 10/22/2018] [Accepted: 11/11/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND Major depressive disorder (MDD) is a prevalent neuropsychiatric disease that carries a staggering global burden. Although numerous antidepressants are available on the market, unfortunately, many patients die by committing suicide as a result of the therapeutic lag between treatment initiation and the improvement of depressive symptoms. This therapeutic lag highlights the need for new antidepressants that provide rapid relief of depressive symptoms. METHOD In this review, we discuss the seminal researches on hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in animal models of depression and highlight the substantial evidence supporting the development of rapid-acting antidepressants targeting HCN channels. RESULTS HCN channels are associated with the risk of depression and targeting HCN channels or its auxiliary subunit tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b) function may exert a rapid antidepressant-like effect. CONCLUSIONS Compounds acting on HCN subunits or the TRIP8b-HCN interaction site may be excellent candidates for development into effective drugs with rapid antidepressant action.
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Affiliation(s)
- Pan Luo
- Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - GuoFang He
- Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Dong Liu
- Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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22
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Günther A, Luczak V, Gruteser N, Abel T, Baumann A. HCN4 knockdown in dorsal hippocampus promotes anxiety-like behavior in mice. GENES BRAIN AND BEHAVIOR 2019; 18:e12550. [PMID: 30585408 PMCID: PMC6850037 DOI: 10.1111/gbb.12550] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 12/03/2018] [Accepted: 12/22/2018] [Indexed: 12/29/2022]
Abstract
Hyperpolarization‐activated and cyclic nucleotide‐gated (HCN) channels mediate the Ih current in the murine hippocampus. Disruption of the Ih current by knockout of HCN1, HCN2 or tetratricopeptide repeat‐containing Rab8b‐interacting protein has been shown to affect physiological processes such as synaptic integration and maintenance of resting membrane potentials as well as several behaviors in mice, including depressive‐like and anxiety‐like behaviors. However, the potential involvement of the HCN4 isoform in these processes is unknown. Here, we assessed the contribution of the HCN4 isoform to neuronal processing and hippocampus‐based behaviors in mice. We show that HCN4 is expressed in various regions of the hippocampus, with distinct expression patterns that partially overlapped with other HCN isoforms. For behavioral analysis, we specifically modulated HCN4 expression by injecting recombinant adeno‐associated viral (rAAV) vectors mediating expression of short hairpin RNA against hcn4 (shHcn4) into the dorsal hippocampus of mice. HCN4 knockdown produced no effect on contextual fear conditioning or spatial memory. However, a pronounced anxiogenic effect was evident in mice treated with shHcn4 compared to control littermates. Our findings suggest that HCN4 specifically contributes to anxiety‐like behaviors in mice.
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Affiliation(s)
- Anne Günther
- Laboratory for Synaptic Molecules of Memory Persistence, Center for Brain Science, RIKEN, Saitama, Japan.,Institute of Complex Systems, Cellular Biophysics (ICS-4),Research Center Jülich, Jülich, Germany
| | - Vincent Luczak
- Division of Biological Sciences and Center for Neural Circuits and Behavior, Neurobiology Section, Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, California, USA
| | - Nadine Gruteser
- Institute of Complex Systems, Cellular Biophysics (ICS-4),Research Center Jülich, Jülich, Germany
| | - Ted Abel
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Arnd Baumann
- Institute of Complex Systems, Cellular Biophysics (ICS-4),Research Center Jülich, Jülich, Germany
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23
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Lyman KA, Han Y, Chetkovich DM. Animal models suggest the TRIP8b-HCN interaction is a therapeutic target for major depressive disorder. Expert Opin Ther Targets 2018; 21:235-237. [PMID: 28127990 DOI: 10.1080/14728222.2017.1287899] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Kyle A Lyman
- a Davee Department of Neurology and Clinical Neurosciences , Northwestern University , Chicago , IL , USA
| | - Ye Han
- a Davee Department of Neurology and Clinical Neurosciences , Northwestern University , Chicago , IL , USA
| | - Dane M Chetkovich
- a Davee Department of Neurology and Clinical Neurosciences , Northwestern University , Chicago , IL , USA
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Meseke M, Neumüller F, Brunne B, Li X, Anstötz M, Pohlkamp T, Rogalla MM, Herz J, Rune GM, Bender RA. Distal Dendritic Enrichment of HCN1 Channels in Hippocampal CA1 Is Promoted by Estrogen, but Does Not Require Reelin. eNeuro 2018; 5:ENEURO.0258-18.2018. [PMID: 30406178 PMCID: PMC6220572 DOI: 10.1523/eneuro.0258-18.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 08/20/2018] [Accepted: 08/26/2018] [Indexed: 12/28/2022] Open
Abstract
HCN1 compartmentalization in CA1 pyramidal cells, essential for hippocampal information processing, is believed to be controlled by the extracellular matrix protein Reelin. Expression of Reelin, in turn, is stimulated by 17β-estradiol (E2). In this study, we therefore tested whether E2 regulates the compartmentalization of HCN1 in CA1 via Reelin. In organotypic entorhino-hippocampal cultures, we found that E2 promotes HCN1 distal dendritic enrichment via the G protein-coupled estrogen receptor GPER1, but apparently independent of Reelin, because GST-RAP, known to reduce Reelin signaling, did not prevent E2-induced HCN1 enrichment in distal CA1. We therefore re-examined the role of Reelin for the regulation of HCN1 compartmentalization and could not detect effects of reduced Reelin signaling on HCN1 distribution in CA1, either in the (developmental) slice culture model or in tamoxifen-inducible conditional reelin knockout mice during adulthood. We conclude that for HCN1 channel compartmentalization in CA1 pyramidal cells, Reelin is not as essential as previously proposed, and E2 effects on HCN1 distribution in CA1 are mediated by mechanisms that do not involve Reelin. Because HCN1 localization was not altered at different phases of the estrous cycle, gonadally derived estradiol is unlikely to regulate HCN1 channel compartmentalization, while the pattern of immunoreactivity of aromatase, the final enzyme of estradiol synthesis, argues for a role of local hippocampal E2 synthesis.
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Affiliation(s)
- Maurice Meseke
- Institute of Neuroanatomy, University Medical Center, Hamburg 20246, Germany
| | - Florian Neumüller
- Institute of Neuroanatomy, University Medical Center, Hamburg 20246, Germany
| | - Bianka Brunne
- Institute of Structural Neurobiology, Center of Molecular Neurobiology, Hamburg 20246, Germany
| | - Xiaoyu Li
- Institute of Neuroanatomy, University Medical Center, Hamburg 20246, Germany
| | - Max Anstötz
- Institute of Neuroanatomy, University Medical Center, Hamburg 20246, Germany
| | - Theresa Pohlkamp
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Meike M. Rogalla
- Institute of Neuroanatomy, University Medical Center, Hamburg 20246, Germany
| | - Joachim Herz
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Gabriele M. Rune
- Institute of Neuroanatomy, University Medical Center, Hamburg 20246, Germany
| | - Roland A. Bender
- Institute of Neuroanatomy, University Medical Center, Hamburg 20246, Germany
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25
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Fisher DW, Han Y, Lyman KA, Heuermann RJ, Bean LA, Ybarra N, Foote KM, Dong H, Nicholson DA, Chetkovich DM. HCN channels in the hippocampus regulate active coping behavior. J Neurochem 2018; 146:753-766. [PMID: 29953635 PMCID: PMC6158061 DOI: 10.1111/jnc.14539] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 06/05/2018] [Accepted: 06/07/2018] [Indexed: 12/16/2022]
Abstract
Active coping is an adaptive stress response that improves outcomes in medical and neuropsychiatric diseases. To date, most research into coping style has focused on neurotransmitter activity and little is known about the intrinsic excitability of neurons in the associated brain regions that facilitate coping. Previous studies have shown that HCN channels regulate neuronal excitability in pyramidal cells and that HCN channel current (Ih ) in the CA1 area increases with chronic mild stress. Reduction of Ih in the CA1 area leads to antidepressant-like behavior, and this region has been implicated in the regulation of coping style. We hypothesized that the antidepressant-like behavior achieved with CA1 knockdown of Ih is accompanied by increases in active coping. In this report, we found that global loss of TRIP8b, a necessary subunit for proper HCN channel localization in pyramidal cells, led to active coping behavior in numerous assays specific to coping style. We next employed a viral strategy using a dominant negative TRIP8b isoform to alter coping behavior by reducing HCN channel expression. This approach led to a robust reduction in Ih in CA1 pyramidal neurons and an increase in active coping. Together, these results establish that changes in HCN channel function in CA1 influences coping style.
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Affiliation(s)
- Daniel W Fisher
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Ye Han
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Kyle A Lyman
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Robert J Heuermann
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Linda A Bean
- Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, USA
| | - Natividad Ybarra
- Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, USA
| | - Kendall M Foote
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Hongxin Dong
- Department of Psychiatry & Behavioral Sciences, Northwestern University, Feinberg School of medicine, Chicago, Illinois, USA
| | - Daniel A Nicholson
- Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, USA
| | - Dane M Chetkovich
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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26
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Store depletion-induced h-channel plasticity rescues a channelopathy linked to Alzheimer's disease. Neurobiol Learn Mem 2018; 154:141-157. [PMID: 29906573 DOI: 10.1016/j.nlm.2018.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 05/25/2018] [Accepted: 06/11/2018] [Indexed: 12/20/2022]
Abstract
Voltage-gated ion channels are critical for neuronal integration. Some of these channels, however, are misregulated in several neurological disorders, causing both gain- and loss-of-function channelopathies in neurons. Using several transgenic mouse models of Alzheimer's disease (AD), we find that sub-threshold voltage signals strongly influenced by hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels progressively deteriorate over chronological aging in hippocampal CA1 pyramidal neurons. The degraded signaling via HCN channels in the transgenic mice is accompanied by an age-related global loss of their non-uniform dendritic expression. Both the aberrant signaling via HCN channels and their mislocalization could be restored using a variety of pharmacological agents that target the endoplasmic reticulum (ER). Our rescue of the HCN channelopathy helps provide molecular details into the favorable outcomes of ER-targeting drugs on the pathogenesis and synaptic/cognitive deficits in AD mouse models, and implies that they might have beneficial effects on neurological disorders linked to HCN channelopathies.
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27
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Silveira Villarroel H, Bompolaki M, Mackay JP, Miranda Tapia AP, Michaelson SD, Leitermann RJ, Marr RA, Urban JH, Colmers WF. NPY Induces Stress Resilience via Downregulation of Ih in Principal Neurons of Rat Basolateral Amygdala. J Neurosci 2018; 38:4505-4520. [PMID: 29650696 PMCID: PMC5943978 DOI: 10.1523/jneurosci.3528-17.2018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/01/2018] [Accepted: 04/05/2018] [Indexed: 01/26/2023] Open
Abstract
Neuropeptide Y (NPY) expression is tightly linked with the development of stress resilience in rodents and humans. Local NPY injections targeting the basolateral amygdala (BLA) produce long-term behavioral stress resilience in male rats via an unknown mechanism. Previously, we showed that activation of NPY Y1 receptors hyperpolarizes BLA principal neurons (PNs) through inhibition of the hyperpolarization-activated, depolarizing H-current, Ih The present studies tested whether NPY treatment induces stress resilience by modulating Ih NPY (10 pmol) was delivered daily for 5 d bilaterally into the BLA to induce resilience; thereafter, the electrophysiological properties of PNs and the expression of Ih in the BLA were characterized. As reported previously, increases in social interaction (SI) times persisted weeks after completion of NPY administration. In vitro intracellular recordings showed that repeated intra-BLA NPY injections resulted in hyperpolarization of BLA PNs at 2 weeks (2W) and 4 weeks (4W) after NPY treatment. At 2W, spontaneous IPSC frequencies were increased, whereas at 4W, resting Ih was markedly reduced and accompanied by decreased levels of HCN1 mRNA and protein expression in BLA. Knock-down of HCN1 channels in the BLA with targeted delivery of lentivirus containing HCN1-shRNA increased SI beginning 2W after injection and induced stress resilience. NPY treatment induced sequential, complementary changes in the inputs to BLA PNs and their postsynaptic properties that reduce excitability, a mechanism that contributes to less anxious behavior. Furthermore, HCN1 knock-down mimicked the increases in SI and stress resilience observed with NPY, indicating the importance of Ih in stress-related behavior.SIGNIFICANCE STATEMENT Resilience improves mental health outcomes in response to adverse situations. Neuropeptide Y (NPY) is associated with decreased stress responses and the expression of resilience in rodents and humans. Single or repeated injections of NPY into the basolateral amygdala (BLA) buffer negative behavioral effects of stress and induce resilience in rats, respectively. Here, we demonstrate that repeated administration of NPY into the BLA unfolds several cellular mechanisms that decrease the activity of pyramidal output neurons. One key mechanism is a reduction in levels of the excitatory ion channel HCN1. Moreover, shRNA knock-down of HCN1 expression in BLA recapitulates some of the actions of NPY and causes potent resilience to stress, indicating that this channel may be a possible target for therapy.
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Affiliation(s)
| | | | - James P Mackay
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | | | - Sheldon D Michaelson
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | | | - Robert A Marr
- Department of Neuroscience, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064
| | | | - William F Colmers
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7,
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28
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Zobeiri M, Chaudhary R, Datunashvili M, Heuermann RJ, Lüttjohann A, Narayanan V, Balfanz S, Meuth P, Chetkovich DM, Pape HC, Baumann A, van Luijtelaar G, Budde T. Modulation of thalamocortical oscillations by TRIP8b, an auxiliary subunit for HCN channels. Brain Struct Funct 2018; 223:1537-1564. [PMID: 29168010 PMCID: PMC5869905 DOI: 10.1007/s00429-017-1559-z] [Citation(s) in RCA: 22] [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: 05/30/2017] [Accepted: 10/30/2017] [Indexed: 12/16/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels have important functions in controlling neuronal excitability and generating rhythmic oscillatory activity. The role of tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b) in regulation of hyperpolarization-activated inward current, I h, in the thalamocortical system and its functional relevance for the physiological thalamocortical oscillations were investigated. A significant decrease in I h current density, in both thalamocortical relay (TC) and cortical pyramidal neurons was found in TRIP8b-deficient mice (TRIP8b-/-). In addition basal cAMP levels in the brain were found to be decreased while the availability of the fast transient A-type K+ current, I A, in TC neurons was increased. These changes were associated with alterations in intrinsic properties and firing patterns of TC neurons, as well as intrathalamic and thalamocortical network oscillations, revealing a significant increase in slow oscillations in the delta frequency range (0.5-4 Hz) during episodes of active-wakefulness. In addition, absence of TRIP8b suppresses the normal desynchronization response of the EEG during the switch from slow-wave sleep to wakefulness. It is concluded that TRIP8b is necessary for the modulation of physiological thalamocortical oscillations due to its direct effect on HCN channel expression in thalamus and cortex and that mechanisms related to reduced cAMP signaling may contribute to the present findings.
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Affiliation(s)
- Mehrnoush Zobeiri
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany.
| | - Rahul Chaudhary
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Maia Datunashvili
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Robert J Heuermann
- Davee Department of Neurology and Clinical Neurosciences and Department of Physiology, Feinberg School of Medicine, Northwestern University, 60611Chicago, USA
| | - Annika Lüttjohann
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Venu Narayanan
- Department of Neurology and Institute of Translational Neurology, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Sabine Balfanz
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Patrick Meuth
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Dane M Chetkovich
- Davee Department of Neurology and Clinical Neurosciences and Department of Physiology, Feinberg School of Medicine, Northwestern University, 60611Chicago, USA
| | - Hans-Christian Pape
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany
| | - Arnd Baumann
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, 52425, Jülich, Germany
| | | | - Thomas Budde
- Institut für Physiologie I, Westfälische Wilhelms-Universität, 48149, Münster, Germany.
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29
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Kato AS, Witkin JM. Protein complexes as psychiatric and neurological drug targets. Biochem Pharmacol 2018; 151:263-281. [PMID: 29330067 DOI: 10.1016/j.bcp.2018.01.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/05/2018] [Indexed: 12/25/2022]
Abstract
The need for improved medications for psychiatric and neurological disorders is clear. Difficulties in finding such drugs demands that all strategic means be utilized for their invention. The discovery of forebrain specific AMPA receptor antagonists, which selectively block the specific combinations of principal and auxiliary subunits present in forebrain regions but spare targets in the cerebellum, was recently disclosed. This discovery raised the possibility that other auxiliary protein systems could be utilized to help identify new medicines. Discussion of the TARP-dependent AMPA receptor antagonists has been presented elsewhere. Here we review the diversity of protein complexes of neurotransmitter receptors in the nervous system to highlight the broad range of protein/protein drug targets. We briefly outline the structural basis of protein complexes as drug targets for G-protein-coupled receptors, voltage-gated ion channels, and ligand-gated ion channels. This review highlights heterodimers, subunit-specific receptor constructions, multiple signaling pathways, and auxiliary proteins with an emphasis on the later. We conclude that the use of auxiliary proteins in chemical compound screening could enhance the detection of specific, targeted drug searches and lead to novel and improved medicines for psychiatric and neurological disorders.
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Affiliation(s)
- Akihiko S Kato
- Neuroscience Discovery, Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA.
| | - Jeffrey M Witkin
- Neuroscience Discovery, Lilly Research Labs, Eli Lilly and Company, Indianapolis, IN, USA
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30
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Sartiani L, Mannaioni G, Masi A, Novella Romanelli M, Cerbai E. The Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels: from Biophysics to Pharmacology of a Unique Family of Ion Channels. Pharmacol Rev 2017; 69:354-395. [PMID: 28878030 DOI: 10.1124/pr.117.014035] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/07/2017] [Indexed: 12/22/2022] Open
Abstract
Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels are important members of the voltage-gated pore loop channels family. They show unique features: they open at hyperpolarizing potential, carry a mixed Na/K current, and are regulated by cyclic nucleotides. Four different isoforms have been cloned (HCN1-4) that can assemble to form homo- or heterotetramers, characterized by different biophysical properties. These proteins are widely distributed throughout the body and involved in different physiologic processes, the most important being the generation of spontaneous electrical activity in the heart and the regulation of synaptic transmission in the brain. Their role in heart rate, neuronal pacemaking, dendritic integration, learning and memory, and visual and pain perceptions has been extensively studied; these channels have been found also in some peripheral tissues, where their functions still need to be fully elucidated. Genetic defects and altered expression of HCN channels are linked to several pathologies, which makes these proteins attractive targets for translational research; at the moment only one drug (ivabradine), which specifically blocks the hyperpolarization-activated current, is clinically available. This review discusses current knowledge about HCN channels, starting from their biophysical properties, origin, and developmental features, to (patho)physiologic role in different tissues and pharmacological modulation, ending with their present and future relevance as drug targets.
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Affiliation(s)
- Laura Sartiani
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Guido Mannaioni
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Alessio Masi
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Maria Novella Romanelli
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Elisabetta Cerbai
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
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31
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Lyman KA, Han Y, Heuermann RJ, Cheng X, Kurz JE, Lyman RE, Van Veldhoven PP, Chetkovich DM. Allostery between two binding sites in the ion channel subunit TRIP8b confers binding specificity to HCN channels. J Biol Chem 2017; 292:17718-17730. [PMID: 28887304 DOI: 10.1074/jbc.m117.802256] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/05/2017] [Indexed: 12/20/2022] Open
Abstract
Tetratricopeptide repeat (TPR) domains are ubiquitous structural motifs that mediate protein-protein interactions. For example, the TPR domains in the peroxisomal import receptor PEX5 enable binding to a range of type 1 peroxisomal targeting signal motifs. A homolog of PEX5, tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b), binds to and functions as an auxiliary subunit of hyperpolarization-activated cyclic nucleotide (HCN)-gated channels. Given the similarity between TRIP8b and PEX5, this difference in function raises the question of what mechanism accounts for their binding specificity. In this report, we found that the cyclic nucleotide-binding domain and the C terminus of the HCN channel are critical for conferring specificity to TRIP8b binding. We show that TRIP8b binds the HCN cyclic nucleotide-binding domain through a 37-residue domain and the HCN C terminus through the TPR domains. Using a combination of fluorescence polarization- and co-immunoprecipitation-based assays, we establish that binding at either site increases affinity at the other. Thus, allosteric coupling of the TRIP8b TPR domains both promotes binding to HCN channels and limits binding to type 1 peroxisomal targeting signal substrates. These results raise the possibility that other TPR domains may be similarly influenced by allosteric mechanisms as a general feature of protein-protein interactions.
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Affiliation(s)
- Kyle A Lyman
- From the Davee Department of Neurology and Clinical Neurosciences and
| | - Ye Han
- From the Davee Department of Neurology and Clinical Neurosciences and
| | | | - Xiangying Cheng
- From the Davee Department of Neurology and Clinical Neurosciences and
| | | | - Reagan E Lyman
- From the Davee Department of Neurology and Clinical Neurosciences and
| | - Paul P Van Veldhoven
- the Laboratory of Lipid Biochemistry and Protein Interactions, Campus Gasthuisberg, KU Leuven, 3000 Leuven, Belgium
| | - Dane M Chetkovich
- From the Davee Department of Neurology and Clinical Neurosciences and .,Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611 and
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32
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Bankston JR, DeBerg HA, Stoll S, Zagotta WN. Mechanism for the inhibition of the cAMP dependence of HCN ion channels by the auxiliary subunit TRIP8b. J Biol Chem 2017; 292:17794-17803. [PMID: 28864772 DOI: 10.1074/jbc.m117.800722] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 08/29/2017] [Indexed: 11/06/2022] Open
Abstract
TRIP8b, an accessory subunit of hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels, alters both the cell surface expression and cyclic nucleotide dependence of these channels. However, the mechanism by which TRIP8b exerts these dual effects is still poorly understood. In addition to binding to the carboxyl-terminal tripeptide of HCN channels, TRIP8b also binds directly to the cyclic nucleotide-binding domain (CNBD). That interaction, which requires a small central portion of TRIP8b termed TRIP8bcore, is both necessary and sufficient for reducing the cAMP-dependent regulation of HCN channels. Here, using fluorescence anisotropy, we report that TRIP8b binding to the CNBD of HCN2 channels decreases the apparent affinity of cAMP for the CNBD. We explored two possible mechanisms for this inhibition. A noncompetitive mechanism in which TRIP8b inhibits the conformational change of the CNBD associated with cAMP regulation and a competitive mechanism in which TRIP8b and cAMP compete for the same binding site. To test these two mechanisms, we used a combination of fluorescence anisotropy, biolayer interferometry, and double electron-electron resonance spectroscopy. Fitting these models to our fluorescence anisotropy binding data revealed that, surprisingly, the TRIP8b-dependent reduction of cAMP binding to the CNBD can largely be explained by partial competition between TRIP8b and cAMP. On the basis of these findings, we propose that TRIP8b competes with a portion of the cAMP-binding site or distorts the binding site by making interactions with the binding pocket, thus acting predominantly as a competitive antagonist that inhibits the cyclic-nucleotide dependence of HCN channels.
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Affiliation(s)
| | - Hannah A DeBerg
- From the Departments of Physiology and Biophysics and.,Chemistry, University of Washington, Seattle, Washington 98195
| | - Stefan Stoll
- Chemistry, University of Washington, Seattle, Washington 98195
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33
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Han Y, Heuermann RJ, Lyman KA, Fisher D, Ismail QA, Chetkovich DM. HCN-channel dendritic targeting requires bipartite interaction with TRIP8b and regulates antidepressant-like behavioral effects. Mol Psychiatry 2017; 22:458-465. [PMID: 27400855 PMCID: PMC5233690 DOI: 10.1038/mp.2016.99] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/25/2016] [Accepted: 05/10/2016] [Indexed: 12/29/2022]
Abstract
Major depressive disorder (MDD) is a prevalent psychiatric condition with limited therapeutic options beyond monoaminergic therapies. Although effective in some individuals, many patients fail to respond adequately to existing treatments, and new pharmacologic targets are needed. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels regulate excitability in neurons, and blocking HCN channel function has been proposed as a novel antidepressant strategy. However, systemic blockade of HCN channels produces cardiac effects that limit this approach. Knockout (KO) of the brain-specific HCN-channel auxiliary subunit tetratricopeptide repeat-containing Rab8b-interacting protein (TRIP8b) also produces antidepressant-like behavioral effects and suggests that inhibiting TRIP8b function could produce antidepressant-like effects without affecting the heart. We examined the structural basis of TRIP8b-mediated HCN-channel trafficking and its relationship with antidepressant-like behavior using a viral rescue approach in TRIP8b KO mice. We found that restoring TRIP8b to the hippocampus was sufficient to reverse the impaired HCN-channel trafficking and antidepressant-like behavioral effects caused by TRIP8b KO. Moreover, we found that hippocampal expression of a mutated version of TRIP8b further impaired HCN-channel trafficking and increased the antidepressant-like behavioral phenotype of TRIP8b KO mice. Thus, modulating the TRIP8b-HCN interaction bidirectionally influences channel trafficking and antidepressant-like behavior. Overall, our work suggests that small-molecule inhibitors of the interaction between TRIP8b and HCN should produce antidepressant-like behaviors and could represent a new paradigm for the treatment of MDD.
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Affiliation(s)
- Ye Han
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University, Chicago, IL 60611 USA
| | - Robert J. Heuermann
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University, Chicago, IL 60611 USA
| | - Kyle A. Lyman
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University, Chicago, IL 60611 USA
| | - Daniel Fisher
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University, Chicago, IL 60611 USA
| | - Quratul-Ain Ismail
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University, Chicago, IL 60611 USA
| | - Dane M. Chetkovich
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University, Chicago, IL 60611 USA
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34
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The Dendrites of CA2 and CA1 Pyramidal Neurons Differentially Regulate Information Flow in the Cortico-Hippocampal Circuit. J Neurosci 2017; 37:3276-3293. [PMID: 28213444 DOI: 10.1523/jneurosci.2219-16.2017] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 12/27/2016] [Accepted: 02/07/2017] [Indexed: 12/29/2022] Open
Abstract
The impact of a given neuronal pathway depends on the number of synapses it makes with its postsynaptic target, the strength of each individual synapse, and the integrative properties of the postsynaptic dendrites. Here we explore the cellular and synaptic mechanisms responsible for the differential excitatory drive from the entorhinal cortical pathway onto mouse CA2 compared with CA1 pyramidal neurons (PNs). Although both types of neurons receive direct input from entorhinal cortex onto their distal dendrites, these inputs produce a 5- to 6-fold larger EPSP at the soma of CA2 compared with CA1 PNs, which is sufficient to drive action potential output from CA2 but not CA1. Experimental and computational approaches reveal that dendritic propagation is more efficient in CA2 than CA1 as a result of differences in dendritic morphology and dendritic expression of the hyperpolarization-activated cation current (Ih). Furthermore, there are three times as many cortical inputs onto CA2 compared with CA1 PN distal dendrites. Using a computational model, we demonstrate that the differences in dendritic properties of CA2 compared with CA1 PNs are necessary to enable the CA2 PNs to generate their characteristically large EPSPs in response to their cortical inputs; in contrast, CA1 dendritic properties limit the size of the EPSPs they generate, even to a similar number of cortical inputs. Thus, the matching of dendritic integrative properties with the density of innervation is crucial for the differential processing of information from the direct cortical inputs by CA2 compared with CA1 PNs.SIGNIFICANCE STATEMENT Recent discoveries have shown that the long-neglected hippocampal CA2 region has distinct synaptic properties and plays a prominent role in social memory and schizophrenia. This study addresses the puzzling finding that the direct entorhinal cortical inputs to hippocampus, which target the very distal pyramidal neuron dendrites, provide an unusually strong excitatory drive at the soma of CA2 pyramidal neurons, with EPSPs that are 5-6 times larger than those in CA1 pyramidal neurons. We here elucidate synaptic and dendritic mechanisms that account quantitatively for the marked difference in EPSP size. Our findings further demonstrate the general importance of fine-tuning the integrative properties of neuronal dendrites to their density of synaptic innervation.
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35
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Heuermann RJ, Jaramillo TC, Ying SW, Suter BA, Lyman KA, Han Y, Lewis AS, Hampton TG, Shepherd GMG, Goldstein PA, Chetkovich DM. Reduction of thalamic and cortical Ih by deletion of TRIP8b produces a mouse model of human absence epilepsy. Neurobiol Dis 2016; 85:81-92. [PMID: 26459112 PMCID: PMC4688217 DOI: 10.1016/j.nbd.2015.10.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 09/22/2015] [Accepted: 10/08/2015] [Indexed: 12/19/2022] Open
Abstract
Absence seizures occur in several types of human epilepsy and result from widespread, synchronous feedback between the cortex and thalamus that produces brief episodes of loss of consciousness. Genetic rodent models have been invaluable for investigating the pathophysiological basis of these seizures. Here, we identify tetratricopeptide-containing Rab8b-interacting protein (TRIP8b) knockout mice as a new model of absence epilepsy, featuring spontaneous spike-wave discharges on electroencephalography (EEG) that are the electrographic hallmark of absence seizures. TRIP8b is an auxiliary subunit of the hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels, which have previously been implicated in the pathogenesis of absence seizures. In contrast to mice lacking the pore-forming HCN channel subunit HCN2, TRIP8b knockout mice exhibited normal cardiac and motor function and a less severe seizure phenotype. Evaluating the circuit that underlies absence seizures, we found that TRIP8b knockout mice had significantly reduced HCN channel expression and function in thalamic-projecting cortical layer 5b neurons and thalamic relay neurons, but preserved function in inhibitory neurons of the reticular thalamic nucleus. Our results expand the known roles of TRIP8b and provide new insight into the region-specific functions of TRIP8b and HCN channels in constraining cortico-thalamo-cortical excitability.
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Affiliation(s)
- Robert J Heuermann
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Thomas C Jaramillo
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Shui-Wang Ying
- C.V. Starr Laboratory for Molecular Neuropharmacology, Department of Anesthesiology, Weill Medical College of Cornell University, 1300 York Ave., Room A-1050, New York, New York 10021, USA.
| | - Benjamin A Suter
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Kyle A Lyman
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Ye Han
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Alan S Lewis
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Thomas G Hampton
- Mouse Specifics, Inc., 2 Central Street, Level 1 Suite 1, Framingham, MA 01701, USA.
| | - Gordon M G Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
| | - Peter A Goldstein
- C.V. Starr Laboratory for Molecular Neuropharmacology, Department of Anesthesiology, Weill Medical College of Cornell University, 1300 York Ave., Room A-1050, New York, New York 10021, USA.
| | - Dane M Chetkovich
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA; Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Ward Building, Room 10-201, Chicago, IL 60611, USA.
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Abstract
The nervous system is populated by numerous types of neurons, each bearing a dendritic arbor with a characteristic morphology. These type-specific features influence many aspects of a neuron's function, including the number and identity of presynaptic inputs and how inputs are integrated to determine firing properties. Here, we review the mechanisms that regulate the construction of cell type-specific dendrite patterns during development. We focus on four aspects of dendrite patterning that are particularly important in determining the function of the mature neuron: (a) dendrite shape, including branching pattern and geometry of the arbor; (b) dendritic arbor size;
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Affiliation(s)
| | - Joshua R Sanes
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138;
| | - Jeremy N Kay
- Departments of Neurobiology and Ophthalmology, Duke University School of Medicine, Durham, North Carolina 27710;
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Pan Y, Laird JG, Yamaguchi DM, Baker SA. An N-Terminal ER Export Signal Facilitates the Plasma Membrane Targeting of HCN1 Channels in Photoreceptors. Invest Ophthalmol Vis Sci 2015; 56:3514-21. [PMID: 26030105 DOI: 10.1167/iovs.15-16902] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Hyperpolarization-activated cyclic nucleotide-gated 1 (HCN1) channels are widely expressed in the retina. In photoreceptors, the hyperpolarization-activated current (Ih) carried by HCN1 is important for shaping the light response. It has been shown in multiple systems that trafficking HCN1 channels to specific compartments is key to their function. The localization of HCN1 in photoreceptors is concentrated in the plasma membrane of the inner segment (IS). The mechanisms controlling this localization are not understood. We previously identified a di-arginine endoplasmic reticulum (ER) retention motif that negatively regulates the surface targeting of HCN1. In this study, we sought to identify a forward trafficking signal that could counter the function of the ER retention signal. METHODS We studied trafficking of HCN1 and several mutants by imaging their subcellular localization in transgenic X. laevis photoreceptors. Velocity sedimentation was used to assay the assembly state of HCN1 channels. RESULTS We found the HCN1 N-terminus can redirect a membrane reporter from outer segments (OS) to the plasma membrane of the IS. The sequence necessary for this behavior was mapped to a 20 amino acid region containing a leucine-based ER export motif. The ER export signal is necessary for forward trafficking but not channel oligomerization. Moreover, this ER export signal alone counteracted the di-arginine ER retention signal. CONCLUSIONS We identified an ER export signal in HCN1 that functions with the ER retention signal to maintain equilibrium of HCN1 between the endomembrane system and the plasma membrane.
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Han Y, Lyman K, Clutter M, Schiltz GE, Ismail QA, Prados DB, Luan CH, Chetkovich DM. Identification of Small-Molecule Inhibitors of Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels. ACTA ACUST UNITED AC 2015; 20:1124-31. [PMID: 26045196 DOI: 10.1177/1087057115589590] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/11/2015] [Indexed: 12/28/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels function in the brain to limit neuronal excitability. Limiting the activity of these channels has been proposed as a therapy for major depressive disorder, but the critical role of HCN channels in cardiac pacemaking has limited efforts to develop therapies directed at the channel. Previous studies indicated that the function of HCN is tightly regulated by its auxiliary subunit, tetratricopeptide repeat-containing Rab8b interacting protein (TRIP8b), which is not expressed in the heart. To target the function of the HCN channel in the brain without affecting the channel's function in the heart, we propose disrupting the interaction between HCN and TRIP8b. We developed a high-throughput fluorescence polarization (FP) assay to identify small molecules capable of disrupting this interaction. We used this FP assay to screen a 20,000-compound library and identified a number of active compounds. The active compounds were validated using an orthogonal AlphaScreen assay to identify one compound (0.005%) as the first confirmed hit for inhibiting the HCN-TRIP8b interaction. Identifying small molecules capable of disrupting the interaction between HCN and TRIP8b should enable the development of new research tools and small-molecule therapies that could benefit patients with depression.
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Affiliation(s)
- Ye Han
- Davee Department of Neurology and Clinical Neurosciences and Department of Physiology, Northwestern University, Chicago, IL, USA
| | - Kyle Lyman
- Davee Department of Neurology and Clinical Neurosciences and Department of Physiology, Northwestern University, Chicago, IL, USA
| | - Matt Clutter
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL, USA
| | - Gary E Schiltz
- Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL, USA
| | - Quratul-Ain Ismail
- Davee Department of Neurology and Clinical Neurosciences and Department of Physiology, Northwestern University, Chicago, IL, USA
| | - Diego Bleifuss Prados
- Davee Department of Neurology and Clinical Neurosciences and Department of Physiology, Northwestern University, Chicago, IL, USA
| | - Chi-Hao Luan
- High Throughput Analysis Laboratory and Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Dane M Chetkovich
- Davee Department of Neurology and Clinical Neurosciences and Department of Physiology, Northwestern University, Chicago, IL, USA
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Distribution and function of HCN channels in the apical dendritic tuft of neocortical pyramidal neurons. J Neurosci 2015; 35:1024-37. [PMID: 25609619 DOI: 10.1523/jneurosci.2813-14.2015] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The apical tuft is the most remote area of the dendritic tree of neocortical pyramidal neurons. Despite its distal location, the apical dendritic tuft of layer 5 pyramidal neurons receives substantial excitatory synaptic drive and actively processes corticocortical input during behavior. The properties of the voltage-activated ion channels that regulate synaptic integration in tuft dendrites have, however, not been thoroughly investigated. Here, we use electrophysiological and optical approaches to examine the subcellular distribution and function of hyperpolarization-activated cyclic nucleotide-gated nonselective cation (HCN) channels in rat layer 5B pyramidal neurons. Outside-out patch recordings demonstrated that the amplitude and properties of ensemble HCN channel activity were uniform in patches excised from distal apical dendritic trunk and tuft sites. Simultaneous apical dendritic tuft and trunk whole-cell current-clamp recordings revealed that the pharmacological blockade of HCN channels decreased voltage compartmentalization and enhanced the generation and spread of apical dendritic tuft and trunk regenerative activity. Furthermore, multisite two-photon glutamate uncaging demonstrated that HCN channels control the amplitude and duration of synaptically evoked regenerative activity in the distal apical dendritic tuft. In contrast, at proximal apical dendritic trunk and somatic recording sites, the blockade of HCN channels decreased excitability. Dynamic-clamp experiments revealed that these compartment-specific actions of HCN channels were heavily influenced by the local and distributed impact of the high density of HCN channels in the distal apical dendritic arbor. The properties and subcellular distribution pattern of HCN channels are therefore tuned to regulate the interaction between integration compartments in layer 5B pyramidal neurons.
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DeBerg HA, Bankston JR, Rosenbaum JC, Brzovic PS, Zagotta WN, Stoll S. Structural mechanism for the regulation of HCN ion channels by the accessory protein TRIP8b. Structure 2015; 23:734-44. [PMID: 25800552 DOI: 10.1016/j.str.2015.02.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/13/2015] [Accepted: 02/09/2015] [Indexed: 11/19/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels underlie the cationic Ih current present in many neurons. The direct binding of cyclic AMP to HCN channels increases the rate and extent of channel opening and results in a depolarizing shift in the voltage dependence of activation. TRIP8b is an accessory protein that regulates the cell surface expression and dendritic localization of HCN channels and reduces the cyclic nucleotide dependence of these channels. Here, we use electron paramagnetic resonance (EPR) to show that TRIP8b binds to the apo state of the cyclic nucleotide binding domain (CNBD) of HCN2 channels without changing the overall domain structure. With EPR and nuclear magnetic resonance, we locate TRIP8b relative to the HCN channel and identify the binding interface on the CNBD. These data provide a structural framework for understanding how TRIP8b regulates the cyclic nucleotide dependence of HCN channels.
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Affiliation(s)
- Hannah A DeBerg
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA; Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - John R Bankston
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Joel C Rosenbaum
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Peter S Brzovic
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - William N Zagotta
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Stefan Stoll
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA.
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Kupferman JV, Basu J, Russo MJ, Guevarra J, Cheung SK, Siegelbaum SA. Reelin signaling specifies the molecular identity of the pyramidal neuron distal dendritic compartment. Cell 2014; 158:1335-1347. [PMID: 25201528 DOI: 10.1016/j.cell.2014.07.035] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 05/27/2014] [Accepted: 07/17/2014] [Indexed: 12/17/2022]
Abstract
The apical dendrites of many neurons contain proximal and distal compartments that receive synaptic inputs from different brain regions. These compartments also contain distinct complements of ion channels that enable the differential processing of their respective synaptic inputs, making them functionally distinct. At present, the molecular mechanisms that specify dendritic compartments are not well understood. Here, we report that the extracellular matrix protein Reelin, acting through its downstream, intracellular Dab1 and Src family tyrosine kinase signaling cascade, is essential for establishing and maintaining the molecular identity of the distal dendritic compartment of cortical pyramidal neurons. We find that Reelin signaling is required for the striking enrichment of HCN1 and GIRK1 channels in the distal tuft dendrites of both hippocampal CA1 and neocortical layer 5 pyramidal neurons, where the channels actively filter inputs targeted to these dendritic domains.
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Affiliation(s)
- Justine V Kupferman
- Department of Biology, Kavli Institute, College of Physicians and Surgeons, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA; Department of Neuroscience, Kavli Institute, College of Physicians and Surgeons, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - Jayeeta Basu
- Department of Neuroscience, Kavli Institute, College of Physicians and Surgeons, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - Marco J Russo
- Department of Neuroscience, Kavli Institute, College of Physicians and Surgeons, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - Jenieve Guevarra
- Department of Biology, Kavli Institute, College of Physicians and Surgeons, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - Stephanie K Cheung
- Department of Neuroscience, Kavli Institute, College of Physicians and Surgeons, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA
| | - Steven A Siegelbaum
- Department of Neuroscience, Kavli Institute, College of Physicians and Surgeons, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA; Department of Pharmacology, Kavli Institute, College of Physicians and Surgeons, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA; Howard Hughes Medical Institute, College of Physicians and Surgeons, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA.
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Pan Y, Laird JG, Yamaguchi DM, Baker SA. A di-arginine ER retention signal regulates trafficking of HCN1 channels from the early secretory pathway to the plasma membrane. Cell Mol Life Sci 2014; 72:833-43. [PMID: 25142030 PMCID: PMC4309907 DOI: 10.1007/s00018-014-1705-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/14/2014] [Accepted: 08/12/2014] [Indexed: 12/25/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated 1 (HCN1) channels carry Ih, which contributes to neuronal excitability and signal transmission in the nervous system. Controlling the trafficking of HCN1 is an important aspect of its regulation, yet the details of this process are poorly understood. Here, we investigated how the C-terminus of HCN1 regulates trafficking by testing for its ability to redirect the localization of a non-targeted reporter in transgenic Xenopus laevis photoreceptors. We found that HCN1 contains an ER localization signal and through a series of deletion constructs, identified the responsible di-arginine ER retention signal. This signal is located in the intrinsically disordered region of the C-terminus of HCN1. To test the function of the ER retention signal in intact channels, we expressed wild type and mutant HCN1 in HEK293 cells and found this signal negatively regulates surface expression of HCN1. In summary, we report a new mode of regulating HCN1 trafficking: through the use of a di-arginine ER retention signal that monitors processing of the channel in the early secretory pathway.
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Affiliation(s)
- Yuan Pan
- Department of Biochemistry, Carver College of Medicine, University of Iowa, 51 Newton Road, Biochemistry, 4-712 BSB, Iowa City, IA, 52242, USA
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Hu L, Santoro B, Saponaro A, Liu H, Moroni A, Siegelbaum S. Binding of the auxiliary subunit TRIP8b to HCN channels shifts the mode of action of cAMP. ACTA ACUST UNITED AC 2014; 142:599-612. [PMID: 24277603 PMCID: PMC3840918 DOI: 10.1085/jgp.201311013] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Hyperpolarization-activated cyclic nucleotide–regulated cation (HCN) channels generate the hyperpolarization-activated cation current Ih present in many neurons. These channels are directly regulated by the binding of cAMP, which both shifts the voltage dependence of HCN channel opening to more positive potentials and increases maximal Ih at extreme negative voltages where voltage gating is complete. Here we report that the HCN channel brain-specific auxiliary subunit TRIP8b produces opposing actions on these two effects of cAMP. In the first action, TRIP8b inhibits the effect of cAMP to shift voltage gating, decreasing both the sensitivity of the channel to cAMP (K1/2) and the efficacy of cAMP (maximal voltage shift); conversely, cAMP binding inhibits these actions of TRIP8b. These mutually antagonistic actions are well described by a cyclic allosteric mechanism in which TRIP8b binding reduces the affinity of the channel for cAMP, with the affinity of the open state for cAMP being reduced to a greater extent than the cAMP affinity of the closed state. In a second apparently independent action, TRIP8b enhances the action of cAMP to increase maximal Ih. This latter effect cannot be explained by the cyclic allosteric model but results from a previously uncharacterized action of TRIP8b to reduce maximal current through the channel in the absence of cAMP. Because the binding of cAMP also antagonizes this second effect of TRIP8b, application of cAMP produces a larger increase in maximal Ih in the presence of TRIP8b than in its absence. These findings may provide a mechanistic explanation for the wide variability in the effects of modulatory transmitters on the voltage gating and maximal amplitude of Ih reported for different neurons in the brain.
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Affiliation(s)
- Lei Hu
- Department of Neuroscience, 2 Department of Pharmacology, and 3 Howard Hughes Medical Institute, Columbia University, New York, NY 10032
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Shah MM. Cortical HCN channels: function, trafficking and plasticity. J Physiol 2014; 592:2711-9. [PMID: 24756635 PMCID: PMC4104471 DOI: 10.1113/jphysiol.2013.270058] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 04/15/2014] [Indexed: 12/26/2022] Open
Abstract
The hyperpolarization-activated cyclic nucleotide-gated (HCN) channels belong to the superfamily of voltage-gated potassium ion channels. They are, however, activated by hyperpolarizing potentials and are permeable to cations. Four HCN subunits have been cloned, of which HCN1 and HCN2 subunits are predominantly expressed in the cortex. These subunits are principally located in pyramidal cell dendrites, although they are also found at lower concentrations in the somata of pyramidal neurons as well as other neuron subtypes. HCN channels are actively trafficked to dendrites by binding to the chaperone protein TRIP8b. Somato-dendritic HCN channels in pyramidal neurons modulate spike firing and synaptic potential integration by influencing the membrane resistance and resting membrane potential. Intriguingly, HCN channels are present in certain cortical axons and synaptic terminals too. Here, they regulate synaptic transmission but the underlying mechanisms appear to vary considerably amongst different synaptic terminals. In conclusion, HCN channels are expressed in multiple neuronal subcellular compartments in the cortex, where they have a diverse and complex effect on neuronal excitability.
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Affiliation(s)
- Mala M Shah
- Department of Pharmacology, UCL School of Pharmacy, London, UK
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Li CJ, Lu Y, Zhou M, Zong XG, Li C, Xu XL, Guo LJ, Lu Q. Activation of GABAB receptors ameliorates cognitive impairment via restoring the balance of HCN1/HCN2 surface expression in the hippocampal CA1 area in rats with chronic cerebral hypoperfusion. Mol Neurobiol 2014; 50:704-20. [PMID: 24838625 DOI: 10.1007/s12035-014-8736-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 04/29/2014] [Indexed: 11/30/2022]
Abstract
Hyperpolarization-activated cyclic-nucleotide-gated cation nonselective (HCN) channels are involved in the pathology of nervous system diseases. HCN channels and γ-aminobutyric acid (GABA) receptors can mutually co-regulate the function of neurons in many brain areas. However, little is known about the co-regulation of HCN channels and GABA receptors in the chronic ischemic rats with possible features of vascular dementia. Protein kinase A (PKA) and TPR containing Rab8b interacting protein (TRIP8b) can modulate GABAB receptors cell surface stability and HCN channel trafficking, respectively, and adaptor-associated kinase 1 (AAK1) inhibits the function of the major TRIP8b-interacting protein adaptor protein 2 (AP2) via phosphorylating the AP2 μ2 subunit. Until now, the role of these regulatory factors in chronic cerebral hypoperfusion is unclear. In the present study, we evaluated whether and how HCN channels and GABAB receptors were pathologically altered and investigated neuroprotective effects of GABAB receptors activation and cross-talk networks between GABAB receptors and HCN channels in the hippocampal CA1 area in chronic cerebral hypoperfusion rat model. We found that cerebral hypoperfusion for 5 weeks by permanent occlusion of bilateral common carotid arteries (two-vessel occlusion, 2VO) induced marked spatial and nonspatial learning and memory deficits, significant neuronal loss and decrease in dendritic spine density, impairment of long-term potentiation (LTP) at the Schaffer collateral-CA1 synapses, and reduction of surface expression of GABAB R1, GABAB R2, and HCN1, but increase in HCN2 surface expression. Meanwhile, the protein expression of TRIP8b (1a-4), TRIP8b (1b-2), and AAK1 was significantly decreased. Baclofen, a GABAB receptor agonist, markedly improved the memory impairment and alleviated neuronal damage. Besides, baclofen attenuated the decrease of surface expression of GABAB R1, GABAB R2, and HCN1, but downregulated HCN2 surface expression. Furthermore, baclofen could restore expression of AAK1 protein and significantly increase p-PKA, TRIP8b (1a-4), TRIP8b (1b-2), and p-AP2 μ2 expression. Those findings suggested that, under chronic cerebral hypoperfusion, activation of PKA could attenuate baclofen-induced decrease in surface expression of GABAB R1 and GABAB R2, and activation of GABAB receptors not only increased the expression of TRIP8b (1a-4) and TRIP8b (1b-2) but also regulated the function of TRIP8b via AAK1 and p-AP2 μ2, which restored the balance of HCN1/HCN2 surface expression in rat hippocampal CA1 area, and thus ameliorated cognitive impairment.
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Affiliation(s)
- Chang-jun Li
- Department of Pharmacology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
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46
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Wilkars W, Wollberg J, Mohr E, Han M, Chetkovich DM, Bähring R, Bender RA. Nedd4‐2 regulates surface expression and may affect
N
‐glycosylation of hyperpolarization‐activated cyclic nucleotide‐gated (HCN)‐1 channels. FASEB J 2014; 28:2177-90. [DOI: 10.1096/fj.13-242032] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Wiebke Wilkars
- Institute of NeuroanatomyUniversity of Hamburg Medical CenterHamburgGermany
| | - Jessica Wollberg
- Institute of Cellular and Integrative PhysiologyUniversity of Hamburg Medical CenterHamburgGermany
| | - Evita Mohr
- Institute of NeuroanatomyUniversity of Hamburg Medical CenterHamburgGermany
| | - Mieri Han
- Institute of NeuroanatomyUniversity of Hamburg Medical CenterHamburgGermany
| | - Dane M. Chetkovich
- Davee Department of Neurology and Clinical NeurosciencesNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
- Department of PhysiologyNorthwestern University Feinberg School of MedicineChicagoIllinoisUSA
| | - Robert Bähring
- Institute of Cellular and Integrative PhysiologyUniversity of Hamburg Medical CenterHamburgGermany
| | - Roland A. Bender
- Institute of NeuroanatomyUniversity of Hamburg Medical CenterHamburgGermany
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Pan Y, Bhattarai S, Modestou M, Drack AV, Chetkovich DM, Baker SA. TRIP8b is required for maximal expression of HCN1 in the mouse retina. PLoS One 2014; 9:e85850. [PMID: 24409334 PMCID: PMC3883711 DOI: 10.1371/journal.pone.0085850] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 10/31/2013] [Indexed: 01/04/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are cation-selective channels present in retina, brain and heart. The activity of HCN channels contributes to signal integration, cell excitability and pacemaker activity. HCN1 channels expressed in photoreceptors participate in keeping light responses transient and are required for normal mesopic vision. The subcellular localization of HCN1 varies among cell types. In photoreceptors HCN1 is concentrated in the inner segments while in other retinal neurons, HCN1 is evenly distributed though the cell. This is in contrast to hippocampal neurons where HCN1 is concentrated in a subset of dendrites. A key regulator of HCN1 trafficking and activity is tetratricopeptide repeat-containing Rab8b interacting protein (TRIP8b). Multiple splice isoforms of TRIP8b are expressed throughout the brain and can differentially regulate the surface expression and activity of HCN1. The purpose of the present study was to determine which isoforms of TRIP8b are expressed in the retina and to test if loss of TRIP8b alters HCN1 expression or trafficking. We found that TRIP8b colocalizes with HCN1 in multiple retina neurons and all major splice isoforms of TRIP8b are expressed in the retina. Photoreceptors express three different isoforms. In TRIP8b knockout mice, the ability of HCN1 to traffic to the surface of retinal neurons is unaffected. However, there is a large decrease in the total amount of HCN1. We conclude that TRIP8b in the retina is needed to achieve maximal expression of HCN1.
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Affiliation(s)
- Yuan Pan
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Sajag Bhattarai
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Modestos Modestou
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Arlene V. Drack
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Dane M. Chetkovich
- The Ken & Ruth Davee Department of Neurology and Clinical Neurosciences and Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Sheila A. Baker
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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He C, Chen F, Li B, Hu Z. Neurophysiology of HCN channels: From cellular functions to multiple regulations. Prog Neurobiol 2014; 112:1-23. [DOI: 10.1016/j.pneurobio.2013.10.001] [Citation(s) in RCA: 230] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 10/01/2013] [Accepted: 10/07/2013] [Indexed: 12/18/2022]
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Delta-opioid receptors mediate unique plasticity onto parvalbumin-expressing interneurons in area CA2 of the hippocampus. J Neurosci 2013; 33:14567-78. [PMID: 24005307 DOI: 10.1523/jneurosci.0649-13.2013] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Inhibition is critical for controlling information transfer in the brain. However, the understanding of the plasticity and particular function of different interneuron subtypes is just emerging. Using acute hippocampal slices prepared from adult mice, we report that in area CA2 of the hippocampus, a powerful inhibitory transmission is acting as a gate to prevent CA3 inputs from driving CA2 neurons. Furthermore, this inhibition is highly plastic, and undergoes a long-term depression following high-frequency 10 Hz or theta-burst induction protocols. We describe a novel form of long-term depression at parvalbumin-expressing (PV+) interneuron synapses that is dependent on delta-opioid receptor (DOR) activation. Additionally, PV+ interneuron transmission is persistently depressed by DOR activation in area CA2 but only transiently depressed in area CA1. These results provide evidence for a differential temporal modulation of PV+ synapses between two adjacent cortical circuits, and highlight a new function of PV+ cells in controlling information transfer.
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Brager DH, Lewis AS, Chetkovich DM, Johnston D. Short- and long-term plasticity in CA1 neurons from mice lacking h-channel auxiliary subunit TRIP8b. J Neurophysiol 2013; 110:2350-7. [PMID: 23966674 PMCID: PMC3841871 DOI: 10.1152/jn.00218.2013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 08/17/2013] [Indexed: 01/11/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated nonselective cation channels (HCN or h-channels) are important regulators of neuronal physiology contributing to passive membrane properties, such as resting membrane potential and input resistance (R(N)), and to intrinsic oscillatory activity and synaptic integration. The correct membrane targeting of h-channels is regulated in part by the auxiliary h-channel protein TRIP8b. The genetic deletion of TRIP8b results in a loss of functional h-channels, which affects the postsynaptic integrative properties of neurons. We investigated the impact of TRIP8b deletion on long-term potentiation (LTP) at the two major excitatory inputs to CA1 pyramidal neurons: Schaffer collateral (SC) and perforant path (PP). We found that SC LTP was not significantly different between neurons from wild-type and TRIP8b-knockout mice. There was, however, significantly more short-term potentiation in knockout neurons. We also found that the persistent increase in h-current (I(h)) that normally occurs after LTP induction was absent in knockout neurons. The lack of I(h) plasticity was not restricted to activity-dependent induction, because the depletion of intracellular calcium stores also failed to produce the expected increase in I(h). Interestingly, pairing of SC and PP inputs resulted in a form of LTP in knockout neurons that did not occur in wild-type neurons. These results suggest that the physiological impact of TRIP8b deletion is not restricted to the integrative properties of neurons but also includes both synaptic and intrinsic plasticity.
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Affiliation(s)
- Darrin H Brager
- Center for Learning and Memory, University of Texas at Austin, Austin, Texas
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