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Kirchner MK, Althammer F, Campos-Lira E, Montanez J, Stern JE. Endoplasmic Reticulum and Mitochondrial Calcium Handling Dynamically Shape Slow Afterhyperpolarizations in Vasopressin Magnocellular Neurons. J Neurosci 2024; 44:e0003242024. [PMID: 38937101 PMCID: PMC11270521 DOI: 10.1523/jneurosci.0003-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 05/15/2024] [Accepted: 06/10/2024] [Indexed: 06/29/2024] Open
Abstract
Many neurons including vasopressin (VP) magnocellular neurosecretory cells (MNCs) of the hypothalamic supraoptic nucleus (SON) generate afterhyperpolarizations (AHPs) during spiking to slow firing, a phenomenon known as spike frequency adaptation. The AHP is underlain by Ca2+-activated K+ currents, and while slow component (sAHP) features are well described, its mechanism remains poorly understood. Previous work demonstrated that Ca2+ influx through N-type Ca2+ channels is a primary source of sAHP activation in SON oxytocin neurons, but no obvious channel coupling was described for VP neurons. Given this, we tested the possibility of an intracellular source of sAHP activation, namely, the Ca2+-handling organelles endoplasmic reticulum (ER) and mitochondria in male and female Wistar rats. We demonstrate that ER Ca2+ depletion greatly inhibits sAHPs without a corresponding decrease in Ca2+ signal. Caffeine sensitized AHP activation by Ca2+ In contrast to ER, disabling mitochondria with CCCP or blocking mitochondria Ca2+ uniporters (MCUs) enhanced sAHP amplitude and duration, implicating mitochondria as a vital buffer for sAHP-activating Ca2+ Block of mitochondria Na+-dependent Ca2+ release via triphenylphosphonium (TPP+) failed to affect sAHPs, indicating that mitochondria Ca2+ does not contribute to sAHP activation. Together, our results suggests that ER Ca2+-induced Ca2+ release activates sAHPs and mitochondria shape the spatiotemporal trajectory of the sAHP via Ca2+ buffering in VP neurons. Overall, this implicates organelle Ca2+, and specifically ER-mitochondria-associated membrane contacts, as an important site of Ca2+ microdomain activity that regulates sAHP signaling pathways. Thus, this site plays a major role in influencing VP firing activity and systemic hormonal release.
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Affiliation(s)
- Matthew K Kirchner
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30303
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
| | - Ferdinand Althammer
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30303
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
| | - Elba Campos-Lira
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30303
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
| | - Juliana Montanez
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30303
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
| | - Javier E Stern
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, Georgia 30303
- Neuroscience Institute, Georgia State University, Atlanta, Georgia 30303
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Qiu J, Voliotis M, Bosch MA, Li XF, Zweifel LS, Tsaneva-Atanasova K, O’Byrne KT, Rønnekleiv OK, Kelly MJ. Estradiol elicits distinct firing patterns in arcuate nucleus kisspeptin neurons of females through altering ion channel conductances. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.20.581121. [PMID: 38915596 PMCID: PMC11195100 DOI: 10.1101/2024.02.20.581121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Hypothalamic kisspeptin (Kiss1) neurons are vital for pubertal development and reproduction. Arcuate nucleus Kiss1 (Kiss1ARH) neurons are responsible for the pulsatile release of Gonadotropin-releasing Hormone (GnRH). In females, the behavior of Kiss1ARH neurons, expressing Kiss1, Neurokinin B (NKB), and Dynorphin (Dyn), varies throughout the ovarian cycle. Studies indicate that 17β-estradiol (E2) reduces peptide expression but increases Vglut2 mRNA and glutamate neurotransmission in these neurons, suggesting a shift from peptidergic to glutamatergic signaling. To investigate this shift, we combined transcriptomics, electrophysiology, and mathematical modeling. Our results demonstrate that E2 treatment upregulates the mRNA expression of voltage-activated calcium channels, elevating the whole-cell calcium current and that contribute to high-frequency burst firing. Additionally, E2 treatment decreased the mRNA levels of Canonical Transient Receptor Potential (TPRC) 5 and G protein-coupled K+ (GIRK) channels. When TRPC5 channels in Kiss1ARH neurons were deleted using CRISPR, the slow excitatory postsynaptic potential (sEPSP) was eliminated. Our data enabled us to formulate a biophysically realistic mathematical model of the Kiss1ARH neuron, suggesting that E2 modifies ionic conductances in Kiss1ARH neurons, enabling the transition from high frequency synchronous firing through NKB-driven activation of TRPC5 channels to a short bursting mode facilitating glutamate release. In a low E2 milieu, synchronous firing of Kiss1ARH neurons drives pulsatile release of GnRH, while the transition to burst firing with high, preovulatory levels of E2 would facilitate the GnRH surge through its glutamatergic synaptic connection to preoptic Kiss1 neurons.
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Affiliation(s)
- Jian Qiu
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
| | - Margaritis Voliotis
- Department of Mathematics and Statistics, University of Exeter, Stocker Rd, Exeter, EX4 4PY, UK
- Living Systems Institute, University of Exeter, Stocker Rd, Exeter, EX4 4PY, UK
| | - Martha A. Bosch
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
| | - Xiao Feng Li
- Department of Women and Children’s Health, School of Life Course and Population Sciences, King’s College London, Guy’s Campus, London SE1 1UL, UK
| | - Larry S. Zweifel
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
- Depatment of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Krasimira Tsaneva-Atanasova
- Department of Mathematics and Statistics, University of Exeter, Stocker Rd, Exeter, EX4 4PY, UK
- Living Systems Institute, University of Exeter, Stocker Rd, Exeter, EX4 4PY, UK
| | - Kevin T. O’Byrne
- Department of Women and Children’s Health, School of Life Course and Population Sciences, King’s College London, Guy’s Campus, London SE1 1UL, UK
| | - Oline K. Rønnekleiv
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006, USA
| | - Martin J. Kelly
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006, USA
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Zhou X, Dong K, Zhang S. Integrating spatial transcriptomics data across different conditions, technologies and developmental stages. NATURE COMPUTATIONAL SCIENCE 2023; 3:894-906. [PMID: 38177758 DOI: 10.1038/s43588-023-00528-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 09/05/2023] [Indexed: 01/06/2024]
Abstract
With the rapid generation of spatial transcriptomics (ST) data, integrative analysis of multiple ST datasets from different conditions, technologies and developmental stages is becoming increasingly important. Here we present a graph attention neural network called STAligner for integrating and aligning ST datasets, enabling spatially aware data integration, simultaneous spatial domain identification and downstream comparative analysis. We apply STAligner to ST datasets of the human cortex slices from different samples, the mouse olfactory bulb slices generated by two profiling technologies, the mouse hippocampus tissue slices under normal and Alzheimer's disease conditions, and the spatiotemporal atlases of mouse organogenesis. STAligner efficiently captures the shared tissue structures across different slices, the disease-related substructures and the dynamical changes during mouse embryonic development. In addition, the shared spatial domain and nearest-neighbor pairs identified by STAligner can be further considered as corresponding pairs to guide the three-dimensional reconstruction of consecutive slices, achieving more accurate local structure-guided registration than the existing method.
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Affiliation(s)
- Xiang Zhou
- NCMIS, CEMS, RCSDS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, China
| | - Kangning Dong
- NCMIS, CEMS, RCSDS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, China
| | - Shihua Zhang
- NCMIS, CEMS, RCSDS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, China.
- School of Mathematical Sciences, University of Chinese Academy of Sciences, Beijing, China.
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China.
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Soloviev A, Ivanova I, Sydorenko V, Sukhanova K, Melnyk M, Dryn D, Zholos A. Calcium-dependent modulation of BK Ca channel activity induced by plasmonic gold nanoparticles in pulmonary artery smooth muscle cells and hippocampal neurons. Acta Physiol (Oxf) 2023; 237:e13922. [PMID: 36599422 DOI: 10.1111/apha.13922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 12/07/2022] [Accepted: 01/02/2023] [Indexed: 01/06/2023]
Abstract
AIM Gold nanoparticles are widely used for biomedical applications, but the precise molecular mechanism of their interaction with cellular structures is still unclear. Assuming that intracellular calcium fluctuations associated with surface plasmon-induced calcium entry could modulate the activity of potassium channels, we studied the effect of 5 nm gold nanoparticles on calcium-dependent potassium channels and associated calcium signaling in freshly isolated rat pulmonary artery smooth muscle cells and cultured hippocampal neurons. METHODS Outward potassium currents were recorded using patch-clamp techniques. Changes in intracellular calcium concentration were measured using the high affinity Ca2+ fluorescent indicator fluo-3 and laser confocal microscope. RESULTS In pulmonary artery smooth muscle cells, plasmonic gold nanoparticles increased the amplitude of currents via large-conductance Ca2+ -activated potassium channels, which was potentiated by green laser irradiation near plasmon resonance wavelength (532 nm). Buffering of intracellular free calcium with ethylene glycol-bis-N,N,N',N'-tetraacetic acid (EGTA) abolished these effects. Furthermore, using confocal laser microscopy it was found that application of gold nanoparticles caused oscillations of intracellular calcium concentration that were decreasing in amplitude with time. In cultured hippocampal neurons gold nanoparticles inhibited the effect of EGTA slowing down the decline of the BKCa current while partially restoring the amplitude of the slow after hyperpolarizing currents. CONCLUSION We conclude that fluctuations in intracellular calcium can modulate plasmonic gold nanoparticles-induced gating of BKCa channels in smooth muscle cells and neurons through an indirect mechanism, probably involving the interaction of plasmon resonance with calcium-permeable ion channels, which leads to a change in intracellular calcium level.
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Affiliation(s)
- Anatoly Soloviev
- Department of Pharmacology of Cell Signaling Systems and Experimental Therapeutics, Institute of Pharmacology and Toxicology, National Academy of Medical Science of Ukraine, Kyiv, Ukraine
| | - Irina Ivanova
- Department of Pharmacology of Cell Signaling Systems and Experimental Therapeutics, Institute of Pharmacology and Toxicology, National Academy of Medical Science of Ukraine, Kyiv, Ukraine
| | - Vadym Sydorenko
- Department of Pharmacology of Cell Signaling Systems and Experimental Therapeutics, Institute of Pharmacology and Toxicology, National Academy of Medical Science of Ukraine, Kyiv, Ukraine
| | - Khrystyna Sukhanova
- McKelvey School of Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Mariia Melnyk
- Department of Biophysics and Medical Informatics, Educational and Scientific Centre "Institute of Biology and Medicine", Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
- Department of Cellular Membranology, A.A. Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Dariia Dryn
- Department of Cellular Membranology, A.A. Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Alexander Zholos
- Department of Biophysics and Medical Informatics, Educational and Scientific Centre "Institute of Biology and Medicine", Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
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Brunetti S, Micheletti S, Palmieri I, Valente EM, Fazzi E. Benign Hereditary Chorea as a Manifestation of HPCA Mutation. Mov Disord Clin Pract 2023; 10:130-134. [PMID: 36704070 PMCID: PMC9847279 DOI: 10.1002/mdc3.13572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/30/2022] [Accepted: 08/28/2022] [Indexed: 01/29/2023] Open
Affiliation(s)
- Sara Brunetti
- Unit of Child Neurology and PsychiatryASST Spedali Civili of BresciaBresciaItaly
| | - Serena Micheletti
- Unit of Child Neurology and PsychiatryASST Spedali Civili of BresciaBresciaItaly
| | - Ilaria Palmieri
- Neurogenetics Research CenterIRCCS Mondino FoundationPaviaItaly
| | - Enza Maria Valente
- Neurogenetics Research CenterIRCCS Mondino FoundationPaviaItaly
- Department of Molecular MedicineUniversity of PaviaPaviaItaly
| | - Elisa Fazzi
- Unit of Child Neurology and PsychiatryASST Spedali Civili of BresciaBresciaItaly
- Department of Clinical and Experimental SciencesUniversity of BresciaBresciaItaly
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Galosi S, Pollini L, Novelli M, Bernardi K, Di Rocco M, Martinelli S, Leuzzi V. Motor, epileptic, and developmental phenotypes in genetic disorders affecting G protein coupled receptors-cAMP signaling. Front Neurol 2022; 13:886751. [PMID: 36003298 PMCID: PMC9393484 DOI: 10.3389/fneur.2022.886751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 07/13/2022] [Indexed: 11/13/2022] Open
Abstract
Over the last years, a constantly increasing number of genetic diseases associated with epilepsy and movement disorders have been recognized. An emerging group of conditions in this field is represented by genetic disorders affecting G-protein-coupled receptors (GPCRs)–cAMP signaling. This group of postsynaptic disorders includes genes encoding for proteins highly expressed in the central nervous system and involved in GPCR signal transduction and cAMP production (e.g., GNAO1, GNB1, ADCY5, GNAL, PDE2A, PDE10A, and HPCA genes). While the clinical phenotype associated with ADCY5 and GNAL is characterized by movement disorder in the absence of epilepsy, GNAO1, GNB1, PDE2A, PDE10A, and HPCA have a broader clinical phenotype, encompassing movement disorder, epilepsy, and neurodevelopmental disorders. We aimed to provide a comprehensive phenotypical characterization of genetic disorders affecting the cAMP signaling pathway, presenting with both movement disorders and epilepsy. Thus, we reviewed clinical features and genetic data of 203 patients from the literature with GNAO1, GNB1, PDE2A, PDE10A, and HPCA deficiencies. Furthermore, we delineated genotype–phenotype correlation in GNAO1 and GNB1 deficiency. This group of disorders presents with a highly recognizable clinical phenotype combining distinctive motor, epileptic, and neurodevelopmental features. A severe hyperkinetic movement disorder with potential life-threatening exacerbations and high susceptibility to a wide range of triggers is the clinical signature of the whole group of disorders. The existence of a distinctive clinical phenotype prompting diagnostic suspicion and early detection has relevant implications for clinical and therapeutic management. Studies are ongoing to clarify the pathophysiology of these rare postsynaptic disorders and start to design disease-specific treatments.
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Affiliation(s)
- Serena Galosi
- Department Human Neuroscience, Sapienza University, Rome, Italy
- *Correspondence: Serena Galosi
| | - Luca Pollini
- Department Human Neuroscience, Sapienza University, Rome, Italy
| | - Maria Novelli
- Department Human Neuroscience, Sapienza University, Rome, Italy
| | | | - Martina Di Rocco
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy
| | - Simone Martinelli
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy
| | - Vincenzo Leuzzi
- Department Human Neuroscience, Sapienza University, Rome, Italy
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Sahu G, Turner RW. The Molecular Basis for the Calcium-Dependent Slow Afterhyperpolarization in CA1 Hippocampal Pyramidal Neurons. Front Physiol 2022; 12:759707. [PMID: 35002757 PMCID: PMC8730529 DOI: 10.3389/fphys.2021.759707] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/01/2021] [Indexed: 12/02/2022] Open
Abstract
Neuronal signal transmission depends on the frequency, pattern, and timing of spike output, each of which are shaped by spike afterhyperpolarizations (AHPs). There are classically three post-spike AHPs of increasing duration categorized as fast, medium and slow AHPs that hyperpolarize a cell over a range of 10 ms to 30 s. Intensive early work on CA1 hippocampal pyramidal cells revealed that all three AHPs incorporate activation of calcium-gated potassium channels. The ionic basis for a fAHP was rapidly attributed to the actions of big conductance (BK) and the mAHP to small conductance (SK) or Kv7 potassium channels. In stark contrast, the ionic basis for a prominent slow AHP of up to 30 s duration remained an enigma for over 30 years. Recent advances in pharmacological, molecular, and imaging tools have uncovered the expression of a calcium-gated intermediate conductance potassium channel (IK, KCa3.1) in central neurons that proves to contribute to the slow AHP in CA1 hippocampal pyramidal cells. Together the data show that the sAHP arises in part from a core tripartite complex between Cav1.3 (L-type) calcium channels, ryanodine receptors, and IK channels at endoplasmic reticulum-plasma membrane junctions. Work on the sAHP in CA1 pyramidal neurons has again quickened pace, with identified contributions by both IK channels and the Na-K pump providing answers to several mysteries in the pharmacological properties of the sAHP.
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Affiliation(s)
- Giriraj Sahu
- National Institute of Pharmaceutical Education and Research Ahmedabad, Ahmedabad, India
| | - Ray W Turner
- Department Cell Biology & Anatomy, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
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Qin X, Liu XX, Wang Y, Wang D, Song Y, Zou JX, Pan HQ, Zhai XZ, Zhang YM, Zhang YB, Hu P, Zhang WH. Early life stress induces anxiety-like behavior during adulthood through dysregulation of neuronal plasticity in the basolateral amygdala. Life Sci 2021; 285:119959. [PMID: 34536496 DOI: 10.1016/j.lfs.2021.119959] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 02/07/2023]
Abstract
AIMS Early life stress (ELS) increases the risk of psychiatric diseases such as anxiety disorders and depression in later life. Hyperactivation of the basolateral amygdala (BLA) neurons plays a pivotal role in the pathogenesis of stress-related diseases. However, the functional roles of BLA neurons in ELS-induced anxiety disorders are not completely understood. MAIN METHODS Mice were subjected to maternal separation (MS) during postnatal days 3 to 21 to mimic ELS. Anxiety-like behavior was tested by open field test (OFT), elevated plus maze (EPM), and novelty suppressed feeding (NSF). Then, c-fos expression, a proxy for neuronal activity, was evaluated by immunofluorescence. Finally, synaptic transmission and intrinsic excitability were measured by whole-cell patch-clamp recordings. KEY FINDINGS MS significantly increased anxiety-like behavior in adulthood, as indicated by less time spent in the center area of the OFT, less time spent in and fewer entries to the open arms of the EPM, and increased latency to feed in NSF. Mechanistically, MS increased the expression of c-fos in BLA. MS enhanced the excitatory, but not inhibitory, synaptic transmission onto BLA projection neurons (PNs), which was caused by enhanced presynaptic glutamate release. Moreover, MS also markedly increased the intrinsic neuronal excitability of BLA PNs, probably due to the reduced medium afterhyperpolarization (mAHP) in BLA PNs. SIGNIFICANCE Our results suggest that the changes of neuronal activity and synaptic transmission in the BLA PNs may play a crucial role in ELS-induced anxiety-like behavior, and these findings provide new insights into the pathological mechanisms of stress-related anxiety disorders.
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Affiliation(s)
- Xia Qin
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China; Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Xiao-Xuan Liu
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China; Neurology Department, the Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Yu Wang
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Dan Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Ying Song
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Jia-Xin Zou
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Han-Qing Pan
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Xiao-Zhou Zhai
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China
| | - Yong-Mei Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Yang-Bo Zhang
- Department of Neurology, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Ping Hu
- Institute of Translational Medicine, Nanchang University, Nanchang 330001, China.
| | - Wen-Hua Zhang
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang 330031, China.
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Facilitating mGluR4 activity reverses the long-term deleterious consequences of chronic morphine exposure in male mice. Neuropsychopharmacology 2021; 46:1373-1385. [PMID: 33349673 PMCID: PMC8136479 DOI: 10.1038/s41386-020-00927-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 11/16/2020] [Accepted: 11/20/2020] [Indexed: 12/13/2022]
Abstract
Understanding the neurobiological underpinnings of abstinence from drugs of abuse is critical to allow better recovery and ensure relapse prevention in addicted subjects. By comparing the long-term transcriptional consequences of morphine and cocaine exposure, we identified the metabotropic glutamate receptor subtype 4 (mGluR4) as a promising pharmacological target in morphine abstinence. We evaluated the behavioral and molecular effects of facilitating mGluR4 activity in abstinent mice. Transcriptional regulation of marker genes of medium spiny neurons (MSNs) allowed best discriminating between 4-week morphine and cocaine abstinence in the nucleus accumbens (NAc). Among these markers, Grm4, encoding mGluR4, displayed down-regulated expression in the caudate putamen and NAc of morphine, but not cocaine, abstinent mice. Chronic administration of the mGluR4 positive allosteric modulator (PAM) VU0155041 (2.5 and 5 mg/kg) rescued social behavior, normalized stereotypies and anxiety and blunted locomotor sensitization in morphine abstinent mice. This treatment improved social preference but increased stereotypies in cocaine abstinent mice. Finally, the beneficial behavioral effects of VU0155041 treatment in morphine abstinent mice were correlated with restored expression of key MSN and neural activity marker genes in the NAc. This study reports that chronic administration of the mGluR4 PAM VU0155041 relieves long-term deleterious consequences of morphine exposure. It illustrates the neurobiological differences between opiate and psychostimulant abstinence and points to pharmacological repression of excessive activity of D2-MSNs in the NAc as a promising therapeutic lever in drug addiction.
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Laker D, Tolle F, Stegen M, Heerdegen M, Köhling R, Kirschstein T, Wolfart J. K v7 and K ir6 Channels Shape the Slow AHP in Mouse Dentate Gyrus Granule Cells and Control Burst-like Firing Behavior. Neuroscience 2021; 467:56-72. [PMID: 34048798 DOI: 10.1016/j.neuroscience.2021.05.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 11/29/2022]
Abstract
The slow afterhyperpolarizing potential (sAHP) can silence a neuron for hundreds of milliseconds. Thereby, the sAHP determines the discharge behavior of many types of neurons. In dentate granule cells (DGCs), serving as a filter into the hippocampal network, mostly tonic or adapting discharge properties have been described. As under standard whole-cell recording conditions the sAHP is inhibited, we reevaluated the intrinsic functional phenotype of DGCs and the conductances underlying the sAHP, using gramicidine-perforated patch-clamp technique. We found that in 97/113 (86%) of the DGCs, a burst of action potentials (APs) to excitation ended by a large sAHP, despite continued depolarization. This result suggests that burst-like firing is the default functional phenotype of DGCs and that sAHPs are important for it. Indeed, burst-like firing DGCs showed a significantly higher sAHP-current (IsAHP) amplitude compared to spike-frequency adapting cells (16/113 = 14%). The IsAHP was mediated by Kv7 and Kir6 channels by pharmacological inhibition using XE991 and tolbutamide, although heterogeneously among DGCs. The percent inhibition of IsAHP by these compounds also correlated with the AP number and AP burst length. Application of 100 µM nickel after XE991 and tolbutamide detected a third conductance contributing to burst-like firing and the sAHP, most likely mediated by T-type calcium channels. Lastly, medial perforant path-dentate gyrus long-term potentiation was amplified by XE991 and tolbutamide. In conclusion, the sAHP shapes intrinsic burst-like firing which, under physiological circumstances, could be controlled via cholinergic afferents and ATP metabolism.
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Affiliation(s)
- Debora Laker
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany
| | - Frederik Tolle
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany
| | - Michael Stegen
- Department of Neurosurgery, University of Freiburg, Germany
| | - Marco Heerdegen
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany.
| | - Jakob Wolfart
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany
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Kelemen K, Szilágyi T. New Approach for Untangling the Role of Uncommon Calcium-Binding Proteins in the Central Nervous System. Brain Sci 2021. [PMID: 34069107 DOI: 10.3390/brainsci11050634ht] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
Although Ca2+ ion plays an essential role in cellular physiology, calcium-binding proteins (CaBPs) were long used for mainly as immunohistochemical markers of specific cell types in different regions of the central nervous system. They are a heterogeneous and wide-ranging group of proteins. Their function was studied intensively in the last two decades and a tremendous amount of information was gathered about them. Girard et al. compiled a comprehensive list of the gene-expression profiles of the entire EF-hand gene superfamily in the murine brain. We selected from this database those CaBPs which are related to information processing and/or neuronal signalling, have a Ca2+-buffer activity, Ca2+-sensor activity, modulator of Ca2+-channel activity, or a yet unknown function. In this way we created a gene function-based selection of the CaBPs. We cross-referenced these findings with publicly available, high-quality RNA-sequencing and in situ hybridization databases (Human Protein Atlas (HPA), Brain RNA-seq database and Allen Brain Atlas integrated into the HPA) and created gene expression heat maps of the regional and cell type-specific expression levels of the selected CaBPs. This represents a useful tool to predict and investigate different expression patterns and functions of the less-known CaBPs of the central nervous system.
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Affiliation(s)
- Krisztina Kelemen
- Department of Physiology, Doctoral School, Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Târgu Mureș, Romania
| | - Tibor Szilágyi
- Department of Physiology, Doctoral School, Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Târgu Mureș, Romania
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Kelemen K, Szilágyi T. New Approach for Untangling the Role of Uncommon Calcium-Binding Proteins in the Central Nervous System. Brain Sci 2021; 11:brainsci11050634. [PMID: 34069107 PMCID: PMC8156796 DOI: 10.3390/brainsci11050634] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/09/2021] [Accepted: 05/10/2021] [Indexed: 02/07/2023] Open
Abstract
Although Ca2+ ion plays an essential role in cellular physiology, calcium-binding proteins (CaBPs) were long used for mainly as immunohistochemical markers of specific cell types in different regions of the central nervous system. They are a heterogeneous and wide-ranging group of proteins. Their function was studied intensively in the last two decades and a tremendous amount of information was gathered about them. Girard et al. compiled a comprehensive list of the gene-expression profiles of the entire EF-hand gene superfamily in the murine brain. We selected from this database those CaBPs which are related to information processing and/or neuronal signalling, have a Ca2+-buffer activity, Ca2+-sensor activity, modulator of Ca2+-channel activity, or a yet unknown function. In this way we created a gene function-based selection of the CaBPs. We cross-referenced these findings with publicly available, high-quality RNA-sequencing and in situ hybridization databases (Human Protein Atlas (HPA), Brain RNA-seq database and Allen Brain Atlas integrated into the HPA) and created gene expression heat maps of the regional and cell type-specific expression levels of the selected CaBPs. This represents a useful tool to predict and investigate different expression patterns and functions of the less-known CaBPs of the central nervous system.
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13
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Keller Sarmiento IJ, Mencacci NE. Genetic Dystonias: Update on Classification and New Genetic Discoveries. Curr Neurol Neurosci Rep 2021; 21:8. [PMID: 33564903 DOI: 10.1007/s11910-021-01095-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2021] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW Since the advent of next-generation sequencing, the number of genes associated with dystonia has been growing exponentially. We provide here a comprehensive review of the latest genetic discoveries in the field of dystonia and discuss how the growing knowledge of biology underlying monogenic dystonias may influence and challenge current classification systems. RECENT FINDINGS Pathogenic variants in genes without previously confirmed roles in human disease have been identified in subjects affected by isolated or combined dystonia (KMT2B, VPS16, HPCA, KCTD17, DNAJC12, SLC18A2) and complex dystonia (SQSTM1, IRF2BPL, YY1, VPS41). Importantly, the classical distinction between isolated and combined dystonias has become harder to sustain since many genes have been shown to determine multiple dystonic presentations (e.g., ANO3, GNAL, ADCY5, and ATP1A3). In addition, a growing number of genes initially linked to other neurological phenotypes, such as developmental delay, epilepsy, or ataxia, are now recognized to cause prominent dystonia, occasionally in an isolated fashion (e.g., GNAO1, GNB1, SCN8A, RHOBTB2, and COQ8A). Finally, emerging analyses suggest biological convergence of genes linked to different dystonic phenotypes. While our knowledge on the genetic basis of monogenic dystonias has tremendously grown, their clinical boundaries are becoming increasingly blurry. The current phenotype-based classification may not reflect the molecular structure of the disease, urging the need for new systems based on shared biological pathways among dystonia-linked genes.
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Affiliation(s)
| | - Niccolò Emanuele Mencacci
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
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Sheremet YE, Olifirov B, Okhrimenko A, Cherkas V, Bagatskaya O, Belan P. Hippocalcin Distribution between the Cytosol and Plasma Membrane of Living Cells. NEUROPHYSIOLOGY+ 2020. [DOI: 10.1007/s11062-020-09845-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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Perturbed Ca2+-dependent signaling of DYT2 hippocalcin mutant as mechanism of autosomal recessive dystonia. Neurobiol Dis 2019; 132:104529. [DOI: 10.1016/j.nbd.2019.104529] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/22/2019] [Accepted: 07/09/2019] [Indexed: 11/23/2022] Open
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16
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Foster TC. Senescent neurophysiology: Ca 2+ signaling from the membrane to the nucleus. Neurobiol Learn Mem 2019; 164:107064. [PMID: 31394200 DOI: 10.1016/j.nlm.2019.107064] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/29/2019] [Accepted: 08/03/2019] [Indexed: 12/16/2022]
Abstract
The current review provides a historical perspective on the evolution of hypothesized mechanisms for senescent neurophysiology, focused on the CA1 region of the hippocampus, and the relationship of senescent neurophysiology to impaired hippocampal-dependent memory. Senescent neurophysiology involves processes linked to calcium (Ca2+) signaling including an increase in the Ca2+-dependent afterhyperpolarization (AHP), decreasing pyramidal cell excitability, hyporesponsiveness of N-methyl-D-aspartate (NMDA) receptor function, and a shift in Ca2+-dependent synaptic plasticity. Dysregulation of intracellular Ca2+ and downstream signaling of kinase and phosphatase activity lies at the core of senescent neurophysiology. Ca2+-dysregulation involves a decrease in Ca2+ influx through NMDA receptors and an increase release of Ca2+ from internal Ca2+ stores. Recent work has identified changes in redox signaling, arising in middle-age, as an initiating factor for senescent neurophysiology. The shift in redox state links processes of aging, oxidative stress and inflammation, with functional changes in mechanisms required for episodic memory. The link between age-related changes in Ca2+ signaling, epigenetics and gene expression is an exciting area of research. Pharmacological and behavioral intervention, initiated in middle-age, can promote memory function by initiating transcription of neuroprotective genes and rejuvenating neurophysiology. However, with more advanced age, or under conditions of neurodegenerative disease, epigenetic changes may weaken the link between environmental influences and transcription, decreasing resilience of memory function.
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Affiliation(s)
- Thomas C Foster
- Department of Neuroscience and Genetics and Genomics Program, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA.
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17
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Byrum SD, Washam CL, Tackett AJ, Garcia-Rill E, Bisagno V, Urbano FJ. Proteomic measures of gamma oscillations. Heliyon 2019; 5:e02265. [PMID: 31497668 PMCID: PMC6722265 DOI: 10.1016/j.heliyon.2019.e02265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/23/2019] [Accepted: 08/06/2019] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Gamma oscillations serve complex processes, and the first stage of their generation is the reticular activating system (RAS), which mediates the gamma-activity states of waking and paradoxical sleep. We studied whether the pedunculopontine nucleus (PPN), part of the RAS in which every cell manifests intrinsic gamma oscillations, undergoes changes resulting in distinctive protein expression. NEW METHOD We previously found that a histone deacetylation inhibitor, trichostatin A (TSA), acutely (30 min) blocked these oscillations. We developed a proteomic method for sampling stimulated and unstimulated PPN and determining protein expression in 1 mm punches of tissue from brain slices subjected to various treatments. RESULTS We compared brain slices exposed for 30 min to TSA (unstimulated), to the cholinergic agonist carbachol (CAR), known to induce PPN gamma oscillations, or exposed to both TSA + CAR.Comparison with existing methods: Label-free proteomics provides an unbiased and sensitive method to detect protein changes in the PPN. Our approach is superior to antibody-based methods that can lack specificity and can only be done for known targets. Proteomics methods like these have been leveraged to study molecular pathways in numerous systems and disease states. CONCLUSIONS Significant protein changes were seen in two functions essential to the physiology of the PPN: cytoskeletal and intracellular [Ca2+] regulation proteins. TSA decreased, while CAR increased, and TSA + CAR had intermediate effects, on expression of these proteins. These results support the feasibility of the methods developed for determining proteomic changes in small samples of tissue participating in the most complex of brain processes.
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Affiliation(s)
- Stephanie D. Byrum
- Center for Translational Pediatric Research, Arkansas Children's Research Institute, Little Rock, AR, USA
| | - Charity L. Washam
- Center for Translational Pediatric Research, Arkansas Children's Research Institute, Little Rock, AR, USA
| | - Alan J. Tackett
- Center for Translational Pediatric Research, Arkansas Children's Research Institute, Little Rock, AR, USA
| | - Edgar Garcia-Rill
- Center for Translational Neuroscience, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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18
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Gohain D, Tamuli R. Calcineurin responsive zinc-finger-1 binds to a unique promoter sequence to upregulate neuronal calcium sensor-1, whose interaction with MID-1 increases tolerance to calcium stress in Neurospora crassa. Mol Microbiol 2019; 111:1510-1528. [PMID: 30825330 DOI: 10.1111/mmi.14234] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2019] [Indexed: 01/24/2023]
Abstract
We studied the molecular mechanism of neuronal calcium sensor-1 (NCS-1) signaling pathway for tolerance to Ca2+ stress in Neurospora crassa. Increasing concentration of Ca2+ increased the expression of ncs-1; however, the calcineurin inhibitor FK506 severely reduced ncs-1 mRNA transcript levels. Chromatin immunoprecipitation (ChIP) studies revealed that the transcription factor calcineurin responsive zinc finger-1 (CRZ-1) binds to the ncs-1 promoter, and CRZ-1 binding upregulated ncs-1 expression under high Ca2+ concentrations. These results suggested the regulation of NCS-1 function through calcineurin- CRZ-1 signaling pathway. Furthermore, the electrophoretic mobility shift assay (EMSA) revealed that the CRZ-1 binds specifically to an 8 bp sequence 5'-CCTTCACA-3' in the ncs-1 promoter 216 bp upstream of the ATG start codon. We also showed that NCS-1 binds to the Ca2+ permeable channel MID-1 for tolerance to Ca2+ stress. Therefore, CRZ-1 binds to a unique sequence in the ncs-1 promoter, causing upregulation of NCS-1 that binds to MID-1 for tolerance to Ca2+ stress.
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Affiliation(s)
- Dibakar Gohain
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781 039, Assam, India
| | - Ranjan Tamuli
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781 039, Assam, India
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Chen KF, Lowe S, Lamaze A, Krätschmer P, Jepson J. Neurocalcin regulates nighttime sleep and arousal in Drosophila. eLife 2019; 8:e38114. [PMID: 30865587 PMCID: PMC6415939 DOI: 10.7554/elife.38114] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 01/29/2019] [Indexed: 01/28/2023] Open
Abstract
Sleep-like states in diverse organisms can be separated into distinct stages, each with a characteristic arousal threshold. However, the molecular pathways underlying different sleep stages remain unclear. The fruit fly, Drosophila melanogaster, exhibits consolidated sleep during both day and night, with night sleep associated with higher arousal thresholds compared to day sleep. Here we identify a role for the neuronal calcium sensor protein Neurocalcin (NCA) in promoting sleep during the night but not the day by suppressing nocturnal arousal and hyperactivity. We show that both circadian and light-sensing pathways define the temporal window in which NCA promotes sleep. Furthermore, we find that NCA promotes sleep by suppressing synaptic release from a dispersed wake-promoting neural network and demonstrate that the mushroom bodies, a sleep-regulatory center, are a module within this network. Our results advance the understanding of how sleep stages are genetically defined.
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Affiliation(s)
- Ko-Fan Chen
- Department of Clinical and Experimental EpilepsyUCL Institute of NeurologyLondonUnited Kingdom
| | - Simon Lowe
- Department of Clinical and Experimental EpilepsyUCL Institute of NeurologyLondonUnited Kingdom
| | - Angélique Lamaze
- Department of Clinical and Experimental EpilepsyUCL Institute of NeurologyLondonUnited Kingdom
| | - Patrick Krätschmer
- Department of Clinical and Experimental EpilepsyUCL Institute of NeurologyLondonUnited Kingdom
| | - James Jepson
- Department of Clinical and Experimental EpilepsyUCL Institute of NeurologyLondonUnited Kingdom
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20
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Key J, Mueller AK, Gispert S, Matschke L, Wittig I, Corti O, Münch C, Decher N, Auburger G. Ubiquitylome profiling of Parkin-null brain reveals dysregulation of calcium homeostasis factors ATP1A2, Hippocalcin and GNA11, reflected by altered firing of noradrenergic neurons. Neurobiol Dis 2019; 127:114-130. [PMID: 30763678 DOI: 10.1016/j.nbd.2019.02.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/05/2018] [Accepted: 02/08/2019] [Indexed: 02/06/2023] Open
Abstract
Parkinson's disease (PD) is the second most frequent neurodegenerative disorder in the old population. Among its monogenic variants, a frequent cause is a mutation in the Parkin gene (Prkn). Deficient function of Parkin triggers ubiquitous mitochondrial dysfunction and inflammation in the brain, but it remains unclear how selective neural circuits become vulnerable and finally undergo atrophy. We attempted to go beyond previous work, mostly done in peripheral tumor cells, which identified protein targets of Parkin activity, an ubiquitin E3 ligase. Thus, we now used aged Parkin-knockout (KO) mouse brain for a global quantification of ubiquitylated peptides by mass spectrometry (MS). This approach confirmed the most abundant substrate to be VDAC3, a mitochondrial outer membrane porin that modulates calcium flux, while uncovering also >3-fold dysregulations for neuron-specific factors. Ubiquitylation decreases were prominent for Hippocalcin (HPCA), Calmodulin (CALM1/CALML3), Pyruvate Kinase (PKM2), sodium/potassium-transporting ATPases (ATP1A1/2/3/4), the Rab27A-GTPase activating protein alpha (TBC1D10A) and an ubiquitin ligase adapter (DDB1), while strong increases occurred for calcium transporter ATP2C1 and G-protein subunits G(i)/G(o)/G(Tr). Quantitative immunoblots validated elevated abundance for the electrogenic pump ATP1A2, for HPCA as neuron-specific calcium sensor, which stimulates guanylate cyclases and modifies axonal slow afterhyperpolarization (sAHP), and for the calcium-sensing G-protein GNA11. We assessed if compensatory molecular regulations become insufficient over time, leading to functional deficits. Patch clamp experiments in acute Parkin-KO brain slices indeed revealed alterations of the electrophysiological properties in aged noradrenergic locus coeruleus (LC) neurons. LC neurons of aged Parkin-KO brain showed an acceleration of the spontaneous pacemaker frequency, a reduction in sAHP and shortening of action potential duration, without modulation of KCNQ potassium currents. These findings indicate altered calcium-dependent excitability in a PARK2 model of PD, mediated by diminished turnover of potential Parkin targets such as ATP1A2 and HPCA. The data also identified further novel Parkin substrate candidates like SIRT2, OTUD7B and CUL5. Our elucidation of neuron-specific mechanisms of PD pathogenesis helps to explain the known exceptional susceptibility of noradrenergic and dopaminergic projections to alterations of calcium homeostasis and its mitochondrial buffering.
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Affiliation(s)
- J Key
- Exp. Neurology, Goethe University Medical School, 60590 Frankfurt am Main, Germany
| | - A K Mueller
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - MCMBB; Clinic for Neurology, Philipps-University Marburg, 35037 Marburg, Germany
| | - S Gispert
- Exp. Neurology, Goethe University Medical School, 60590 Frankfurt am Main, Germany
| | - L Matschke
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - MCMBB; Clinic for Neurology, Philipps-University Marburg, 35037 Marburg, Germany
| | - I Wittig
- Functional Proteomics, SFB 815 Core Unit, Goethe University Medical School, 60590 Frankfurt am Main, Germany
| | - O Corti
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, F-75013, France; Inserm, U1127, Paris, F-75013, France; CNRS, UMR 7225, Paris, F-75013, France; Sorbonne Universités, Paris, F-75013, France
| | - C Münch
- Institute of Biochemistry II, Goethe University Medical School, 60590 Frankfurt am Main, Germany
| | - N Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology and Marburg Center for Mind, Brain and Behavior - MCMBB; Clinic for Neurology, Philipps-University Marburg, 35037 Marburg, Germany.
| | - G Auburger
- Exp. Neurology, Goethe University Medical School, 60590 Frankfurt am Main, Germany.
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21
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Church TW, Brown JT, Marrion NV. β 3-Adrenergic receptor-dependent modulation of the medium afterhyperpolarization in rat hippocampal CA1 pyramidal neurons. J Neurophysiol 2019; 121:773-784. [PMID: 30625002 DOI: 10.1152/jn.00334.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Action potential firing in hippocampal pyramidal neurons is regulated by generation of an afterhyperpolarization (AHP). Three phases of AHP are recognized, with the fast AHP regulating action potential firing at the onset of a burst and the medium and slow AHPs supressing action potential firing over hundreds of milliseconds and seconds, respectively. Activation of β-adrenergic receptors suppresses the slow AHP by a protein kinase A-dependent pathway. However, little is known regarding modulation of the medium AHP. Application of the selective β-adrenergic receptor agonist isoproterenol suppressed both the medium and slow AHPs evoked in rat CA1 hippocampal pyramidal neurons recorded from slices maintained in organotypic culture. Suppression of the slow AHP was mimicked by intracellular application of cAMP, with the suppression of the medium AHP by isoproterenol still being evident in cAMP-dialyzed cells. Suppression of both the medium and slow AHPs was antagonized by the β-adrenergic receptor antagonist propranolol. The effect of isoproterenol to suppress the medium AHP was mimicked by two β3-adrenergic receptor agonists, BRL37344 and SR58611A. The medium AHP was mediated by activation of small-conductance calcium-activated K+ channels and deactivation of H channels at the resting membrane potential. Suppression of the medium AHP by isoproterenol was reduced by pretreating cells with the H-channel blocker ZD7288. These data suggest that activation of β3-adrenergic receptors inhibits H channels, which suppresses the medium AHP in CA1 hippocampal neurons by utilizing a pathway that is independent of a rise in intracellular cAMP. This finding highlights a potential new target in modulating H-channel activity and thereby neuronal excitability. NEW & NOTEWORTHY The noradrenergic input into the hippocampus is involved in modulating long-term synaptic plasticity and is implicated in learning and memory. We demonstrate that activation of functional β3-adrenergic receptors suppresses the medium afterhyperpolarization in hippocampal pyramidal neurons. This finding provides an additional mechanism to increase action potential firing frequency, where neuronal excitability is likely to be crucial in cognition and memory.
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Affiliation(s)
- Timothy W Church
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
| | - Jon T Brown
- University of Exeter Medical School , Exeter , United Kingdom
| | - Neil V Marrion
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
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22
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Ames JB. Dimerization of Neuronal Calcium Sensor Proteins. Front Mol Neurosci 2018; 11:397. [PMID: 30450035 PMCID: PMC6224351 DOI: 10.3389/fnmol.2018.00397] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/11/2018] [Indexed: 12/27/2022] Open
Abstract
Neuronal calcium sensor (NCS) proteins are EF-hand containing Ca2+ binding proteins that regulate sensory signal transduction. Many NCS proteins (recoverin, GCAPs, neurocalcin and visinin-like protein 1 (VILIP1)) form functional dimers under physiological conditions. The dimeric NCS proteins have similar amino acid sequences (50% homology) but each bind to and regulate very different physiological targets. Retinal recoverin binds to rhodopsin kinase and promotes Ca2+-dependent desensitization of light-excited rhodopsin during visual phototransduction. The guanylyl cyclase activating proteins (GCAP1–5) each bind and activate retinal guanylyl cyclases (RetGCs) in light-adapted photoreceptors. VILIP1 binds to membrane targets that modulate neuronal secretion. Here, I review atomic-level structures of dimeric forms of recoverin, GCAPs and VILIP1. The distinct dimeric structures in each case suggest that NCS dimerization may play a role in modulating specific target recognition. The dimerization of recoverin and VILIP1 is Ca2+-dependent and enhances their membrane-targeting Ca2+-myristoyl switch function. The dimerization of GCAP1 and GCAP2 facilitate their binding to dimeric RetGCs and may allosterically control the Ca2+-dependent activation of RetGCs.
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Affiliation(s)
- James B Ames
- Department of Chemistry, University of California, Davis, Davis, CA, United States
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Abstract
Dystonia is a neurological condition characterized by abnormal involuntary movements or postures owing to sustained or intermittent muscle contractions. Dystonia can be the manifesting neurological sign of many disorders, either in isolation (isolated dystonia) or with additional signs (combined dystonia). The main focus of this Primer is forms of isolated dystonia of idiopathic or genetic aetiology. These disorders differ in manifestations and severity but can affect all age groups and lead to substantial disability and impaired quality of life. The discovery of genes underlying the mendelian forms of isolated or combined dystonia has led to a better understanding of its pathophysiology. In some of the most common genetic dystonias, such as those caused by TOR1A, THAP1, GCH1 and KMT2B mutations, and idiopathic dystonia, these mechanisms include abnormalities in transcriptional regulation, striatal dopaminergic signalling and synaptic plasticity and a loss of inhibition at neuronal circuits. The diagnosis of dystonia is largely based on clinical signs, and the diagnosis and aetiological definition of this disorder remain a challenge. Effective symptomatic treatments with pharmacological therapy (anticholinergics), intramuscular botulinum toxin injection and deep brain stimulation are available; however, future research will hopefully lead to reliable biomarkers, better treatments and cure of this disorder.
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Atasu B, Hanagasi H, Bilgic B, Pak M, Erginel-Unaltuna N, Hauser AK, Guven G, Simón-Sánchez J, Heutink P, Gasser T, Lohmann E. HPCA confirmed as a genetic cause of DYT2-like dystonia phenotype. Mov Disord 2018; 33:1354-1358. [PMID: 30145809 DOI: 10.1002/mds.27442] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 04/24/2018] [Accepted: 05/02/2018] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND HPCA (hippocalcin) is one of the underlying genetic causes of autosomal-recessively inherited forms of dystonia. Here, we describe two consanguineous Turkish DYT-HPCA families carrying the novel HPCA mutations. METHODS After detailed clinical and neurological examination, whole-exome sequencing was performed. RESULTS Whole-exome sequencing analysis revealed two homozygous novel truncating mutations (p.W103* and p.P10PfsTer80) in the HPCA gene in two unrelated Turkish dystonia families presenting with complex dystonia. CONCLUSIONS After identification of HPCA as a genetic cause of DYT-HPCA-like dystonia by Charlesworth et al, this is the second report in the scientific literature that describes dystonia families harboring HPCA mutations. Our findings confirm that HPCA leads to recessively inherited dystonia. © 2018 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Burcu Atasu
- German Center for Neurodegenerative Diseases (DZNE)-Tübingen, Tübingen, Germany.,Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Hasmet Hanagasi
- Behavioural Neurology and Movement Disorders Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Basar Bilgic
- Behavioural Neurology and Movement Disorders Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Meltem Pak
- Behavioural Neurology and Movement Disorders Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Nihan Erginel-Unaltuna
- Aziz Sancar Institute for Experimental Medicine, Genetics Department, Istanbul University, Istanbul, Turkey
| | - Ann-Kathrin Hauser
- German Center for Neurodegenerative Diseases (DZNE)-Tübingen, Tübingen, Germany.,Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Gamze Guven
- Aziz Sancar Institute for Experimental Medicine, Genetics Department, Istanbul University, Istanbul, Turkey
| | - Javier Simón-Sánchez
- German Center for Neurodegenerative Diseases (DZNE)-Tübingen, Tübingen, Germany.,Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Peter Heutink
- German Center for Neurodegenerative Diseases (DZNE)-Tübingen, Tübingen, Germany.,Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Thomas Gasser
- German Center for Neurodegenerative Diseases (DZNE)-Tübingen, Tübingen, Germany.,Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Ebba Lohmann
- German Center for Neurodegenerative Diseases (DZNE)-Tübingen, Tübingen, Germany.,Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Behavioural Neurology and Movement Disorders Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
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25
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Kirchner MK, Foehring RC, Callaway J, Armstrong WE. Specificity in the interaction of high-voltage-activated Ca 2+ channel types with Ca 2+-dependent afterhyperpolarizations in magnocellular supraoptic neurons. J Neurophysiol 2018; 120:1728-1739. [PMID: 30020842 DOI: 10.1152/jn.00285.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Magnocellular oxytocin (OT) and vasopressin (VP) neurons express an afterhyperpolarization (AHP) following spike trains that attenuates firing rate and contributes to burst patterning. This AHP includes contributions from an apamin-sensitive, medium-duration AHP (mAHP) and from an apamin-insensitive, slow-duration AHP (sAHP). These AHPs are Ca2+ dependent and activated by Ca2+ influx through voltage-gated Ca2+ channels. Across central nervous system neurons that generate Ca2+-dependent AHPs, the Ca2+ channels that couple to the mAHP and sAHP differ greatly, but for magnocellular neurosecretory cells this relationship is unknown. Using simultaneous whole cell recording and Ca2+ imaging, we evaluated the effect of specific high-voltage-activated (HVA) Ca2+ channel blockers on the mAHP and sAHP. Block of all HVA channels via 400 μM Cd2+ inhibited almost the entire AHP. We tested nifedipine, conotoxin GVIA, agatoxin IVA, and SNX-482, specific blockers of L-, N-, P/Q-, and R-type channels, respectively. The N-type channel blocker conotoxin GVIA (1 μM) was the only toxin that inhibited the mAHP in either OT or VP neurons although the effect on VP neurons was weaker by comparison. The sAHP was significantly inhibited by N-type block in OT neurons and by R-type block in VP neurons although neither accounted for the entirety of the sAHP. Thus the mAHP appears to be elicited by Ca2+ from mostly N-type channels in both OT and VP neurons, but the contributions of specific Ca2+ channel types to the sAHP in each cell type are different. Alternative sources to HVA channels may contribute Ca2+ for the sAHP. NEW & NOTEWORTHY Despite the importance of afterhyperpolarization (AHP) mechanisms for regulating firing behavior of oxytocin (OT) and vasopressin (VP) neurons of supraoptic nucleus, which types of high-voltage-activated Ca2+ channels elicit AHPs in these cells was unknown. We found that N-type channels couple to the medium AHP in both cell types. For the slow AHP, N-type channels contribute in OT neurons, whereas R-type contribute in VP neurons. No single Ca2+ channel blocker abolished the entire AHP, suggesting that additional Ca2+ sources are involved.
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Affiliation(s)
- Matthew K Kirchner
- University of Tennessee Health Science Center, Department of Anatomy & Neurobiology
| | - Robert C Foehring
- University of Tennessee Health Science Center, Department of Anatomy & Neurobiology
| | - Joseph Callaway
- University of Tennessee Health Science Center, Department of Anatomy & Neurobiology
| | - William E Armstrong
- University of Tennessee Health Science Center, Department of Anatomy & Neurobiology
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Muzyka VV, Brooks M, Badea TC. Postnatal developmental dynamics of cell type specification genes in Brn3a/Pou4f1 Retinal Ganglion Cells. Neural Dev 2018; 13:15. [PMID: 29958540 PMCID: PMC6025728 DOI: 10.1186/s13064-018-0110-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 06/06/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND About 20-30 distinct Retinal Ganglion Cell (RGC) types transmit visual information from the retina to the brain. The developmental mechanisms by which RGCs are specified are still largely unknown. Brn3a is a member of the Brn3/Pou4f transcription factor family, which contains key regulators of RGC postmitotic specification. In particular, Brn3a ablation results in the loss of RGCs with small, thick and dense dendritic arbors ('midget-like' RGCs), and morphological changes in other RGC subpopulations. To identify downstream molecular mechanisms underlying Brn3a effects on RGC numbers and morphology, our group recently performed a RNA deep sequencing screen for Brn3a transcriptional targets in mouse RGCs and identified 180 candidate transcripts. METHODS We now focus on a subset of 28 candidate genes encoding potential cell type determinant proteins. We validate and further define their retinal expression profile at five postnatal developmental time points between birth and adult stage, using in situ hybridization (ISH), RT-PCR and fluorescent immunodetection (IIF). RESULTS We find that a majority of candidate genes are enriched in the ganglion cell layer during early stages of postnatal development, but dynamically change their expression profile. We also document transcript-specific expression differences for two example candidates, using RT-PCR and ISH. Brn3a dependency could be confirmed by ISH and IIF only for a fraction of our candidates. CONCLUSIONS Amongst our candidate Brn3a target genes, a majority demonstrated ganglion cell layer specificity, however only around two thirds showed Brn3a dependency. Some were previously implicated in RGC type specification, while others have known physiological functions in RGCs. Only three genes were found to be consistently regulated by Brn3a throughout postnatal retina development - Mapk10, Tusc5 and Cdh4.
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Affiliation(s)
| | - Matthew Brooks
- Genomics Core, Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, NIH, Building 6, Room 331B Center Drive, Bethesda, MD, 20892-0610, USA
| | - Tudor Constantin Badea
- Retinal Circuit Development & Genetics Unit, Building 6, Room 331B Center Drive, Bethesda, MD, 20892-0610, USA.
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27
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Tian J, Vemula SR, Xiao J, Valente EM, Defazio G, Petrucci S, Gigante AF, Rudzińska‐Bar M, Wszolek ZK, Kennelly KD, Uitti RJ, van Gerpen JA, Hedera P, Trimble EJ, LeDoux MS. Whole-exome sequencing for variant discovery in blepharospasm. Mol Genet Genomic Med 2018; 6:601-626. [PMID: 29770609 PMCID: PMC6081235 DOI: 10.1002/mgg3.411] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/01/2018] [Accepted: 04/16/2018] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Blepharospasm (BSP) is a type of focal dystonia characterized by involuntary orbicularis oculi spasms that are usually bilateral, synchronous, and symmetrical. Despite strong evidence for genetic contributions to BSP, progress in the field has been constrained by small cohorts, incomplete penetrance, and late age of onset. Although several genetic etiologies for dystonia have been identified through whole-exome sequencing (WES), none of these are characteristically associated with BSP as a singular or predominant manifestation. METHODS We performed WES on 31 subjects from 21 independent pedigrees with BSP. The strongest candidate sequence variants derived from in silico analyses were confirmed with bidirectional Sanger sequencing and subjected to cosegregation analysis. RESULTS Cosegregating deleterious variants (GRCH37/hg19) in CACNA1A (NM_001127222.1: c.7261_7262delinsGT, p.Pro2421Val), REEP4 (NM_025232.3: c.109C>T, p.Arg37Trp), TOR2A (NM_130459.3: c.568C>T, p.Arg190Cys), and ATP2A3 (NM_005173.3: c.1966C>T, p.Arg656Cys) were identified in four independent multigenerational pedigrees. Deleterious variants in HS1BP3 (NM_022460.3: c.94C>A, p.Gly32Cys) and GNA14 (NM_004297.3: c.989_990del, p.Thr330ArgfsTer67) were identified in a father and son with segmental cranio-cervical dystonia first manifest as BSP. Deleterious variants in DNAH17, TRPV4, CAPN11, VPS13C, UNC13B, SPTBN4, MYOD1, and MRPL15 were found in two or more independent pedigrees. To our knowledge, none of these genes have previously been associated with isolated BSP, although other CACNA1A mutations have been associated with both positive and negative motor disorders including ataxia, episodic ataxia, hemiplegic migraine, and dystonia. CONCLUSIONS Our WES datasets provide a platform for future studies of BSP genetics which will demand careful consideration of incomplete penetrance, pleiotropy, population stratification, and oligogenic inheritance patterns.
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Affiliation(s)
- Jun Tian
- Departments of Neurology and Anatomy and NeurobiologyUniversity of Tennessee Health Science CenterMemphisTennessee
- Department of NeurologySecond Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouZhejiangChina
| | - Satya R. Vemula
- Departments of Neurology and Anatomy and NeurobiologyUniversity of Tennessee Health Science CenterMemphisTennessee
| | - Jianfeng Xiao
- Departments of Neurology and Anatomy and NeurobiologyUniversity of Tennessee Health Science CenterMemphisTennessee
| | - Enza Maria Valente
- Department of Molecular MedicineUniversity of PaviaPaviaItaly
- Neurogenetics UnitIRCCS Santa Lucia FoundationRomeItaly
| | - Giovanni Defazio
- Department of Basic Clinical Sciences, Neuroscience and Sense OrgansAldo Moro University of BariBariItaly
- Department of Medical Sciences and Public HealthUniversity of CagliariCagliariItaly
| | - Simona Petrucci
- Department of Neurology and PsychiatrySapienza University of RomeRomeItaly
| | - Angelo Fabio Gigante
- Department of Basic Clinical Sciences, Neuroscience and Sense OrgansAldo Moro University of BariBariItaly
| | - Monika Rudzińska‐Bar
- Department of NeurologyFaculty of MedicineMedical University of SilesiaKatowicePoland
| | | | | | - Ryan J. Uitti
- Department of NeurologyMayo Clinic FloridaJacksonvilleFlorida
| | | | - Peter Hedera
- Department of NeurologyVanderbilt UniversityNashvilleTennessee
| | - Elizabeth J. Trimble
- Departments of Neurology and Anatomy and NeurobiologyUniversity of Tennessee Health Science CenterMemphisTennessee
| | - Mark S. LeDoux
- Departments of Neurology and Anatomy and NeurobiologyUniversity of Tennessee Health Science CenterMemphisTennessee
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Helassa N, Antonyuk SV, Lian LY, Haynes LP, Burgoyne RD. Biophysical and functional characterization of hippocalcin mutants responsible for human dystonia. Hum Mol Genet 2017; 26:2426-2435. [PMID: 28398555 PMCID: PMC5886089 DOI: 10.1093/hmg/ddx133] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 03/29/2017] [Indexed: 11/13/2022] Open
Abstract
Dystonia is a neurological movement disorder that forces the body into twisting, repetitive movements or sometimes painful abnormal postures. With the advent of next-generation sequencing technologies, the homozygous mutations T71N and A190T in the neuronal calcium sensor (NCS) hippocalcin were identified as the genetic cause of primary isolated dystonia (DYT2 dystonia). However, the effect of these mutations on the physiological role of hippocalcin has not yet been elucidated. Using a multidisciplinary approach, we demonstrated that hippocalcin oligomerises in a calcium-dependent manner and binds to voltage-gated calcium channels. Mutations T71N and A190T in hippocalcin did not affect stability, calcium-binding affinity or translocation to cellular membranes (Ca2+/myristoyl switch). We obtained the first crystal structure of hippocalcin and alignment with other NCS proteins showed significant variability in the orientation of the C-terminal part of the molecule, the region expected to be important for target binding. We demonstrated that the disease-causing mutations did not affect the structure of the protein, however both mutants showed a defect in oligomerisation. In addition, we observed an increased calcium influx in KCl-depolarised cells expressing mutated hippocalcin, mostly driven by N-type voltage-gated calcium channels. Our data demonstrate that the dystonia-causing mutations strongly affect hippocalcin cellular functions which suggest a central role for perturbed calcium signalling in DYT2 dystonia.
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Affiliation(s)
- Nordine Helassa
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool L69?3BX, UK
| | - Svetlana V Antonyuk
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69?7ZB, UK and
| | - Lu-Yun Lian
- NMR Centre for Structural Biology, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69?7ZB, UK
| | - Lee P Haynes
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool L69?3BX, UK
| | - Robert D Burgoyne
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool L69?3BX, UK
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Pacheco NL, Heaven MR, Holt LM, Crossman DK, Boggio KJ, Shaffer SA, Flint DL, Olsen ML. RNA sequencing and proteomics approaches reveal novel deficits in the cortex of Mecp2-deficient mice, a model for Rett syndrome. Mol Autism 2017; 8:56. [PMID: 29090078 PMCID: PMC5655833 DOI: 10.1186/s13229-017-0174-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/02/2017] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused by mutations in the transcriptional regulator MeCP2. Much of our understanding of MeCP2 function is derived from transcriptomic studies with the general assumption that alterations in the transcriptome correlate with proteomic changes. Advances in mass spectrometry-based proteomics have facilitated recent interest in the examination of global protein expression to better understand the biology between transcriptional and translational regulation. METHODS We therefore performed the first comprehensive transcriptome-proteome comparison in a RTT mouse model to elucidate RTT pathophysiology, identify potential therapeutic targets, and further our understanding of MeCP2 function. The whole cortex of wild-type and symptomatic RTT male littermates (n = 4 per genotype) were analyzed using RNA-sequencing and data-independent acquisition liquid chromatography tandem mass spectrometry. Ingenuity® Pathway Analysis was used to identify significantly affected pathways in the transcriptomic and proteomic data sets. RESULTS Our results indicate these two "omics" data sets supplement one another. In addition to confirming previous works regarding mRNA expression in Mecp2-deficient animals, the current study identified hundreds of novel protein targets. Several selected protein targets were validated by Western blot analysis. These data indicate RNA metabolism, proteostasis, monoamine metabolism, and cholesterol synthesis are disrupted in the RTT proteome. Hits common to both data sets indicate disrupted cellular metabolism, calcium signaling, protein stability, DNA binding, and cytoskeletal cell structure. Finally, in addition to confirming disrupted pathways and identifying novel hits in neuronal structure and synaptic transmission, our data indicate aberrant myelination, inflammation, and vascular disruption. Intriguingly, there is no evidence of reactive gliosis, but instead, gene, protein, and pathway analysis suggest astrocytic maturation and morphological deficits. CONCLUSIONS This comparative omics analysis supports previous works indicating widespread CNS dysfunction and may serve as a valuable resource for those interested in cellular dysfunction in RTT.
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Affiliation(s)
- Natasha L. Pacheco
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35294 USA
| | - Michael R. Heaven
- Vulcan Analytical, LLC, 1500 1st Ave. North, Birmingham, AL 35203 USA
| | - Leanne M. Holt
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35294 USA
- School of Neuroscience, Virginia Polytechnic and State University, Life Sciences Building Room 213, 970 Washington St. SW, Blacksburg, VA 24061 USA
| | - David K. Crossman
- UAB Heflin Center for Genomic Science, Department of Genetics, University of Alabama at Birmingham, Kaul 424A, 1720 2nd Ave. South, Birmingham, AL 35294 USA
| | - Kristin J. Boggio
- Proteomics and Mass Spectrometry Facility, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 222 Maple Ave., Fuller Building, Shrewsbury, MA 01545 USA
| | - Scott A. Shaffer
- Proteomics and Mass Spectrometry Facility, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 222 Maple Ave., Fuller Building, Shrewsbury, MA 01545 USA
| | - Daniel L. Flint
- Luxumbra Strategic Research, LLC, 1331 South Eads St, Arlington, VA 22202 USA
| | - Michelle L. Olsen
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35294 USA
- School of Neuroscience, Virginia Polytechnic and State University, Life Sciences Building Room 213, 970 Washington St. SW, Blacksburg, VA 24061 USA
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Shakkottai VG, Batla A, Bhatia K, Dauer WT, Dresel C, Niethammer M, Eidelberg D, Raike RS, Smith Y, Jinnah HA, Hess EJ, Meunier S, Hallett M, Fremont R, Khodakhah K, LeDoux MS, Popa T, Gallea C, Lehericy S, Bostan AC, Strick PL. Current Opinions and Areas of Consensus on the Role of the Cerebellum in Dystonia. THE CEREBELLUM 2017; 16:577-594. [PMID: 27734238 DOI: 10.1007/s12311-016-0825-6] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A role for the cerebellum in causing ataxia, a disorder characterized by uncoordinated movement, is widely accepted. Recent work has suggested that alterations in activity, connectivity, and structure of the cerebellum are also associated with dystonia, a neurological disorder characterized by abnormal and sustained muscle contractions often leading to abnormal maintained postures. In this manuscript, the authors discuss their views on how the cerebellum may play a role in dystonia. The following topics are discussed: The relationships between neuronal/network dysfunctions and motor abnormalities in rodent models of dystonia. Data about brain structure, cerebellar metabolism, cerebellar connections, and noninvasive cerebellar stimulation that support (or not) a role for the cerebellum in human dystonia. Connections between the cerebellum and motor cortical and sub-cortical structures that could support a role for the cerebellum in dystonia. Overall points of consensus include: Neuronal dysfunction originating in the cerebellum can drive dystonic movements in rodent model systems. Imaging and neurophysiological studies in humans suggest that the cerebellum plays a role in the pathophysiology of dystonia, but do not provide conclusive evidence that the cerebellum is the primary or sole neuroanatomical site of origin.
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Affiliation(s)
- Vikram G Shakkottai
- Department of Neurology, University of Michigan, Room 4009, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA. .,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
| | - Amit Batla
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, London, UK
| | - Kailash Bhatia
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, London, UK
| | - William T Dauer
- Department of Neurology, University of Michigan, Room 4009, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA.,Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Christian Dresel
- Center for Neurosciences, The Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - Martin Niethammer
- Center for Neurosciences, The Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - David Eidelberg
- Center for Neurosciences, The Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - Robert S Raike
- Global Research Organization, Medtronic Inc. Neuromodulation, Minneapolis, MN, USA
| | - Yoland Smith
- Yerkes National Primate Center and Department of Neurology, Emory University, Atlanta, GA, USA
| | - H A Jinnah
- Department of Neurology, Human Genetics and Pediatrics, Emory University, Atlanta, GA, USA
| | - Ellen J Hess
- Departments of Pharmacology and Neurology, Emory University, Atlanta, GA, USA
| | - Sabine Meunier
- Institut du Cerveau et de la Moelle épinière (ICM), Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR, S 1127, Paris, France.,Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Mark Hallett
- Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Rachel Fremont
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, USA
| | - Kamran Khodakhah
- Dominick P. Purpura Department of Neuroscience, Department of Psychiatry and Behavioral Sciences, and The Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, New York, NY, USA
| | - Mark S LeDoux
- Departments of Neurology, and Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Traian Popa
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Cécile Gallea
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France.,Centre de NeuroImagerie de Recherche - CENIR, ICM, F-75013, Paris, France
| | - Stéphane Lehericy
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Andreea C Bostan
- Systems Neuroscience Institute and Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Peter L Strick
- Systems Neuroscience Institute and Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Neurobiology, University of Pittsburgh Brain Institute, University of Pittsburgh, Pittsburgh, PA, USA
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Kirchner MK, Foehring RC, Wang L, Chandaka GK, Callaway JC, Armstrong WE. Phosphatidylinositol 4,5-bisphosphate (PIP 2 ) modulates afterhyperpolarizations in oxytocin neurons of the supraoptic nucleus. J Physiol 2017; 595:4927-4946. [PMID: 28383826 DOI: 10.1113/jp274219] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 04/04/2017] [Indexed: 01/19/2023] Open
Abstract
KEY POINTS Afterhyperpolarizations (AHPs) generated by repetitive action potentials in supraoptic magnocellular neurons regulate repetitive firing and spike frequency adaptation but relatively little is known about PIP2 's control of these AHPs. We examined how changes in PIP2 levels affected AHPs, somatic [Ca2+ ]i , and whole cell Ca2+ currents. Manipulations of PIP2 levels affected both medium and slow AHP currents in oxytocin (OT) neurons of the supraoptic nucleus. Manipulations of PIP2 levels did not modulate AHPs by influencing Ca2+ release from IP3 -triggered Ca2+ stores, suggesting more direct modulation of channels by PIP2 . PIP2 depletion reduced spike-evoked Ca2+ entry and voltage-gated Ca2+ currents. PIP2 appears to influence AHPs in OT neurons by reducing Ca2+ influx during spiking. ABSTRACT Oxytocin (OT)- and vasopressin (VP)-secreting magnocellular neurons of the supraoptic nucleus (SON) display calcium-dependent afterhyperpolarizations (AHPs) following a train of action potentials that are critical to shaping the firing patterns of these cells. Previous work demonstrated that the lipid phosphatidylinositol 4,5-bisphosphate (PIP2 ) enabled the slow AHP component (sAHP) in cortical pyramidal neurons. We investigated whether this phenomenon occurred in OT and VP neurons of the SON. Using whole cell recordings in coronal hypothalamic slices from adult female rats, we demonstrated that inhibition of PIP2 synthesis with wortmannin robustly blocked both the medium and slow AHP currents (ImAHP and IsAHP ) of OT, but not VP neurons with high affinity. We further tested this by introducing a water-soluble PIP2 analogue (diC8 -PIP2 ) into neurons, which in OT neurons not only prevented wortmannin's inhibitory effect, but slowed rundown of the ImAHP and IsAHP . Inhibition of phospholipase C (PLC) with U73122 did not inhibit either ImAHP or IsAHP in OT neurons, consistent with wortmannin's effects not being due to reducing diacylglycerol (DAG) or IP3 availability, i.e. PIP2 modulation of AHPs is not likely to involve downstream Ca2+ release from inositol 1,4,5-trisphosphate (IP3 )-triggered Ca2+ -store release, or channel modulation via DAG and protein kinase C (PKC). We found that wortmannin reduced [Ca2+ ]i increase induced by spike trains in OT neurons, but had no effect on AHPs evoked by uncaging intracellular Ca2+ . Finally, wortmannin selectively reduced whole cell Ca2+ currents in OT neurons while leaving VP neurons unaffected. The results indicate that PIP2 modulates both the ImAHP and IsAHP in OT neurons, most likely by controlling Ca2+ entry through voltage-gated Ca2+ channels opened during spike trains.
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Affiliation(s)
- Matthew K Kirchner
- Department of Anatomy and Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Robert C Foehring
- Department of Anatomy and Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Lie Wang
- Department of Anatomy and Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Giri Kumar Chandaka
- Department of Anatomy and Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Joseph C Callaway
- Department of Anatomy and Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN, USA
| | - William E Armstrong
- Department of Anatomy and Neurobiology and Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN, USA
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Kim KS, Duignan KM, Hawryluk JM, Soh H, Tzingounis AV. The Voltage Activation of Cortical KCNQ Channels Depends on Global PIP2 Levels. Biophys J 2016; 110:1089-98. [PMID: 26958886 DOI: 10.1016/j.bpj.2016.01.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 01/12/2016] [Accepted: 01/13/2016] [Indexed: 01/22/2023] Open
Abstract
The slow afterhyperpolarization (sAHP) is a calcium-activated potassium conductance with critical roles in multiple physiological processes. Pharmacological and genetic data suggest that KCNQ channels partly mediate the sAHP. However, these channels are not typically open within the observed voltage range of the sAHP. Recent work has shown that the sAHP is gated by increased PIP2 levels, which are generated downstream of calcium binding by neuronal calcium sensors such as hippocalcin. Here, we examined whether changes in PIP2 levels could shift the voltage-activation range of KCNQ channels. In HEK293T cells, expression of the PIP5 kinase PIPKIγ90, which increases global PIP2 levels, shifted the KCNQ voltage activation to within the operating range of the sAHP. Further, the sensitivity of this effect on KCNQ3 channels appeared to be higher than that on KCNQ2. Therefore, we predict that KCNQ3 plays an essential role in maintaining the sAHP under low PIP2 conditions. In support of this notion, we find that sAHP inhibition by muscarinic receptors that increase phosphoinositide turnover in neurons is enhanced in Kcnq3-knockout mice. Likewise, the presence of KCNQ3 is essential for maintaining the sAHP when hippocalcin is ablated, a condition that likely impairs PIP2 generation. Together, our results establish the relationship between PIP2 and the voltage dependence of cortical KCNQ channels (KCNQ2/3, KCNQ3/5, and KCNQ5), and suggest a possible mechanism for the involvement of KCNQ channels in the sAHP.
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Affiliation(s)
- Kwang S Kim
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Kevin M Duignan
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Joanna M Hawryluk
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Heun Soh
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
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Li C, Lim S, Braunewell KH, Ames JB. Structure and Calcium Binding Properties of a Neuronal Calcium-Myristoyl Switch Protein, Visinin-Like Protein 3. PLoS One 2016; 11:e0165921. [PMID: 27820860 PMCID: PMC5098827 DOI: 10.1371/journal.pone.0165921] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 10/19/2016] [Indexed: 12/13/2022] Open
Abstract
Visinin-like protein 3 (VILIP-3) belongs to a family of Ca2+-myristoyl switch proteins that regulate signal transduction in the brain and retina. Here we analyze Ca2+ binding, characterize Ca2+-induced conformational changes, and determine the NMR structure of myristoylated VILIP-3. Three Ca2+ bind cooperatively to VILIP-3 at EF2, EF3 and EF4 (KD = 0.52 μM and Hill slope of 1.8). NMR assignments, mutagenesis and structural analysis indicate that the covalently attached myristoyl group is solvent exposed in Ca2+-bound VILIP-3, whereas Ca2+-free VILIP-3 contains a sequestered myristoyl group that interacts with protein residues (E26, Y64, V68), which are distinct from myristate contacts seen in other Ca2+-myristoyl switch proteins. The myristoyl group in VILIP-3 forms an unusual L-shaped structure that places the C14 methyl group inside a shallow protein groove, in contrast to the much deeper myristoyl binding pockets observed for recoverin, NCS-1 and GCAP1. Thus, the myristoylated VILIP-3 protein structure determined in this study is quite different from those of other known myristoyl switch proteins (recoverin, NCS-1, and GCAP1). We propose that myristoylation serves to fine tune the three-dimensional structures of neuronal calcium sensor proteins as a means of generating functional diversity.
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Affiliation(s)
- Congmin Li
- Department of Chemistry, University of California Davis, Davis, CA, United States of America
| | - Sunghyuk Lim
- Department of Chemistry, University of California Davis, Davis, CA, United States of America
| | - Karl H. Braunewell
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - James B. Ames
- Department of Chemistry, University of California Davis, Davis, CA, United States of America
- * E-mail:
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34
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Greene DL, Hoshi N. Modulation of Kv7 channels and excitability in the brain. Cell Mol Life Sci 2016; 74:495-508. [PMID: 27645822 DOI: 10.1007/s00018-016-2359-y] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/25/2016] [Accepted: 09/06/2016] [Indexed: 11/26/2022]
Abstract
Neuronal Kv7 channels underlie a voltage-gated non-inactivating potassium current known as the M-current. Due to its particular characteristics, Kv7 channels show pronounced control over the excitability of neurons. We will discuss various factors that have been shown to drastically alter the activity of this channel such as protein and phospholipid interactions, phosphorylation, calcium, and numerous neurotransmitters. Kv7 channels locate to key areas for the control of action potential initiation and propagation. Moreover, we will explore the dynamic surface expression of the channel modulated by neurotransmitters and neural activity. We will also focus on known principle functions of neural Kv7 channels: control of resting membrane potential and spiking threshold, setting the firing frequency, afterhyperpolarization after burst firing, theta resonance, and transient hyperexcitability from neurotransmitter-induced suppression of the M-current. Finally, we will discuss the contribution of altered Kv7 activity to pathologies such as epilepsy and cognitive deficits.
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Affiliation(s)
- Derek L Greene
- Department of Pharmacology, University of California, 360 Med Surge II, Irvine, CA, 92697, USA
| | - Naoto Hoshi
- Department of Pharmacology, University of California, 360 Med Surge II, Irvine, CA, 92697, USA.
- Department of Physiology and Biophysics, University of California, Irvine, USA.
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35
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Study of the anti-seizure effects of low-frequency stimulation following kindling (a review of the cellular mechanism related to the anti-seizure effects of low-frequency electrical stimulation). Neurol Sci 2016; 38:19-26. [DOI: 10.1007/s10072-016-2694-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 08/17/2016] [Indexed: 02/04/2023]
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Choi HS, Lee CH. Time-course changes of hippocalcin expression in the mouse hippocampus following pilocarpine-induced status epilepticus. J Vet Sci 2016; 17:137-44. [PMID: 26435544 PMCID: PMC4921661 DOI: 10.4142/jvs.2016.17.2.137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 07/14/2015] [Accepted: 08/22/2015] [Indexed: 11/20/2022] Open
Abstract
Hippocalcin participates in the maintenance of neuronal calcium homeostasis. In the present study, we examined the time-course changes of neuronal degeneration and hippocalcin protein level in the mouse hippocampus following pilocarpine-induced status epilepticus (SE). Marked neuronal degeneration was observed in the hippocampus after SE in a time-dependent manner, although neuronal degeneration differed according to the hippocampal subregions. Almost no hippocalcin immunoreactivity was detected in the pyramidal neurons of the cornu ammonis 1 (CA1) region from 6 h after SE. However, many pyramidal neurons in the CA2 region showed hippocalcin immunoreactivity until 24 h after SE. In the CA3 region, only a few hippocalcin immunoreactive cells were observed at 12 h after SE, and almost no hippocalcin immunoreactivity was observed in the pyramidal neurons from 24 h after SE. Hippocalcin immunoreactivity in the polymorphic cells of the dentate gyrus was markedly decreased from 6 h after SE. In addition, hippocalcin protein level in the hippocampus began to decrease from 6 h after SE, and was significantly decreased at 24 h and 48 h after pilocarpine-induced SE. These results indicate that marked reduction of hippocalcin level may be closely related to neuronal degeneration in the hippocampus following pilocarpine-induced SE.
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Affiliation(s)
- Hee-Soo Choi
- Department of Pharmacy, College of Pharmacy, Dankook University, Cheonan 31116, Korea
| | - Choong-Hyun Lee
- Department of Pharmacy, College of Pharmacy, Dankook University, Cheonan 31116, Korea
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Rannals MD, Hamersky GR, Page SC, Campbell MN, Briley A, Gallo RA, Phan BN, Hyde TM, Kleinman JE, Shin JH, Jaffe AE, Weinberger DR, Maher BJ. Psychiatric Risk Gene Transcription Factor 4 Regulates Intrinsic Excitability of Prefrontal Neurons via Repression of SCN10a and KCNQ1. Neuron 2016; 90:43-55. [PMID: 26971948 PMCID: PMC4824652 DOI: 10.1016/j.neuron.2016.02.021] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 10/09/2015] [Accepted: 02/12/2016] [Indexed: 01/28/2023]
Abstract
Transcription Factor 4 (TCF4) is a clinically pleiotropic gene associated with schizophrenia and Pitt-Hopkins syndrome (PTHS). To gain insight about the neurobiology of TCF4, we created an in vivo model of PTHS by suppressing Tcf4 expression in rat prefrontal neurons immediately prior to neurogenesis. This cell-autonomous genetic insult attenuated neuronal spiking by increasing the afterhyperpolarization. At the molecular level, using a novel technique called iTRAP that combined in utero electroporation and translating ribosome affinity purification, we identified increased translation of two ion channel genes, Kcnq1 and Scn10a. These ion channel candidates were validated by pharmacological rescue and molecular phenocopy. Remarkably, similar excitability deficits were observed in prefrontal neurons from a Tcf4(+/tr) mouse model of PTHS. Thus, we identify TCF4 as a regulator of neuronal intrinsic excitability in part by repression of Kcnq1 and Scn10a and suggest that this molecular function may underlie pathophysiology associated with neuropsychiatric disorders.
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Affiliation(s)
- Matthew D Rannals
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Gregory R Hamersky
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Stephanie Cerceo Page
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Morganne N Campbell
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Aaron Briley
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Ryan A Gallo
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - BaDoi N Phan
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Thomas M Hyde
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Neurology and the McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Joel E Kleinman
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Neurology and the McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Joo Heon Shin
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Andrew E Jaffe
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Daniel R Weinberger
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Neurology and the McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Brady J Maher
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
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Wang K, Mateos-Aparicio P, Hönigsperger C, Raghuram V, Wu WW, Ridder MC, Sah P, Maylie J, Storm JF, Adelman JP. IK1 channels do not contribute to the slow afterhyperpolarization in pyramidal neurons. eLife 2016; 5:e11206. [PMID: 26765773 PMCID: PMC4733036 DOI: 10.7554/elife.11206] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/01/2015] [Indexed: 11/16/2022] Open
Abstract
In pyramidal neurons such as hippocampal area CA1 and basolateral amygdala, a slow afterhyperpolarization (sAHP) follows a burst of action potentials, which is a powerful regulator of neuronal excitability. The sAHP amplitude increases with aging and may underlie age related memory decline. The sAHP is due to a Ca2+-dependent, voltage-independent K+ conductance, the molecular identity of which has remained elusive until a recent report suggested the Ca2+-activated K+ channel, IK1 (KCNN4) as the sAHP channel in CA1 pyramidal neurons. The signature pharmacology of IK1, blockade by TRAM-34, was reported for the sAHP and underlying current. We have examined the sAHP and find no evidence that TRAM-34 affects either the current underling the sAHP or excitability of CA1 or basolateral amygdala pyramidal neurons. In addition, CA1 pyramidal neurons from IK1 null mice exhibit a characteristic sAHP current. Our results indicate that IK1 channels do not mediate the sAHP in pyramidal neurons. DOI:http://dx.doi.org/10.7554/eLife.11206.001 Neurons carry signals in the form of electrical impulses called action potentials. These nerve impulses result from ions flowing through proteins called ion channels in the neuron’s membrane, and they determine how the neuron communicates with neighboring neurons. The number of action potentials a neuron can produce can vary over a wide range. In the brain, a particular kind of ion channel limits the number of action potentials that many neurons produce via a negative feedback mechanism. That is to say, nerve impulses activate this ion channel and the activated channel then makes the neuron less able to send further nerve impulses for a while.The activity of this ion channel increases with age and it may be responsible for some forms of age-related decline in cognitive abilities. However, the exact identity of the ion channel responsible was unclear. Recent research has suggested the ion channel in question was a protein called IK1. This conclusion was largely based on how this ion channel responded to drugs in the laboratory. Wang, Materos-Aparico et al. sought to verify this conclusion and, in contrast with the previous reports, found that the IK1 ion channel did not respond to these drugs in the same way when it was in neurons in the brains of mice. In further experiments, mice that had been engineered to lack the IK1 ion channel still showed the characteristic negative feedback that regulates the firing of action potentials. Thus, Wang, Materos-Aparico et al. found no evidence to support the previous conclusion, and instead conclude that the exact identity of this important ion channel in the brain has yet to be defined. DOI:http://dx.doi.org/10.7554/eLife.11206.002
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Affiliation(s)
- Kang Wang
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Pedro Mateos-Aparicio
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Christoph Hönigsperger
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Vijeta Raghuram
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Wendy W Wu
- Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, United States
| | - Margreet C Ridder
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Pankaj Sah
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Jim Maylie
- Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, United States
| | - Johan F Storm
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - John P Adelman
- Vollum Institute, Oregon Health and Science University, Portland, United States
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Mutations in HPCA cause autosomal-recessive primary isolated dystonia. Am J Hum Genet 2015; 96:657-65. [PMID: 25799108 PMCID: PMC4385177 DOI: 10.1016/j.ajhg.2015.02.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 02/06/2015] [Indexed: 12/20/2022] Open
Abstract
Reports of primary isolated dystonia inherited in an autosomal-recessive (AR) manner, often lumped together as “DYT2 dystonia,” have appeared in the scientific literature for several decades, but no genetic cause has been identified to date. Using a combination of homozygosity mapping and whole-exome sequencing in a consanguineous kindred affected by AR isolated dystonia, we identified homozygous mutations in HPCA, a gene encoding a neuronal calcium sensor protein found almost exclusively in the brain and at particularly high levels in the striatum, as the cause of disease in this family. Subsequently, compound-heterozygous mutations in HPCA were also identified in a second independent kindred affected by AR isolated dystonia. Functional studies suggest that hippocalcin might play a role in regulating voltage-dependent calcium channels. The identification of mutations in HPCA as a cause of AR primary isolated dystonia paves the way for further studies to assess whether “DYT2 dystonia” is a genetically homogeneous condition or not.
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Ginsenoside Rd promotes neurogenesis in rat brain after transient focal cerebral ischemia via activation of PI3K/Akt pathway. Acta Pharmacol Sin 2015; 36:421-8. [PMID: 25832422 DOI: 10.1038/aps.2014.156] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 12/20/2014] [Indexed: 12/11/2022] Open
Abstract
AIM To investigate the effects of ginsenoside Rd (Rd) on neurogenesis in rat brain after ischemia/reperfusion injury (IRI). METHODS Male SD rats were subjected to transient middle cerebral artery occlusion (MCAO) followed by reperfusion. The rats were injected with Rd (1, 2.5, and 5 mg·kg(-1)·d(-1), ip) from d 1 to d 3 after MCAO, and with BrdU (50 mg·kg(-1)·d(-1), ip) from d 3 to d 6, then sacrificed on 7 d. The infarct size and neurological scores were assessed. Neurogenesis in the brains was detected by BrdU, DCX, Nestin, and GFAP immunohistochemistry staining. PC12 cells subjected to OGD/reperfusion were used as an in vitro model of brain ischemia. VEGF and BDNF levels were assessed with ELISA, and Akt and ERK phosphorylation was measured using Western blotting. RESULTS Rd administration dose-dependently decreased the infarct size and neurological scores in the rats with IRI. The high dose of Rd 5 (mg·kg(-1)·d(-1)) significantly increased Akt phosphorylation in ipsilateral hemisphere, and markedly increased the number of BrdU/DCX and Nestin/GFAP double-positive cells in ischemic area, which was partially blocked by co-administration of the PI3 kinase inhibitor LY294002. Treatment with Rd (25, 50, and 100 μmol/L) during reperfusion significantly increased the expression of VEGF and BDNF in PC12 cells with IRI. Furthermore, treatment with Rd dose-dependently increased the phosphorylation of Akt and ERK, and significantly decreased PC12 cell apoptosis, which were blocked by co-application of LY294002. CONCLUSION Rd not only attenuates ischemia/reperfusion injury in rat brain, but also promotes neurogenesis via increasing VEGF and BDNF expression and activating the PI3K/Akt and ERK1/2 pathways.
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Buchta WC, Riegel AC. Chronic cocaine disrupts mesocortical learning mechanisms. Brain Res 2015; 1628:88-103. [PMID: 25704202 DOI: 10.1016/j.brainres.2015.02.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 01/28/2015] [Accepted: 02/01/2015] [Indexed: 01/06/2023]
Abstract
The addictive power of drugs of abuse such as cocaine comes from their ability to hijack natural reward and plasticity mechanisms mediated by dopamine signaling in the brain. Reward learning involves burst firing of midbrain dopamine neurons in response to rewards and cues predictive of reward. The resulting release of dopamine in terminal regions is thought to act as a teaching signaling to areas such as the prefrontal cortex and striatum. In this review, we posit that a pool of extrasynaptic dopaminergic D1-like receptors activated in response to dopamine neuron burst firing serve to enable synaptic plasticity in the prefrontal cortex in response to rewards and their cues. We propose that disruptions in these mechanisms following chronic cocaine use contribute to addiction pathology, in part due to the unique architecture of the mesocortical pathway. By blocking dopamine reuptake in the cortex, cocaine elevates dopamine signaling at these extrasynaptic receptors, prolonging D1-receptor activation and the subsequent activation of intracellular signaling cascades, and thus inducing long-lasting maladaptive plasticity. These cellular adaptations may account for many of the changes in cortical function observed in drug addicts, including an enduring vulnerability to relapse. Therefore, understanding and targeting these neuroadaptations may provide cognitive benefits and help prevent relapse in human drug addicts.
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Affiliation(s)
- William C Buchta
- Neurobiology of Addiction Research Center (NARC), Medical University of South Carolina, Charleston, SC 29425, USA
| | - Arthur C Riegel
- Neurobiology of Addiction Research Center (NARC), Medical University of South Carolina, Charleston, SC 29425, USA.
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42
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Burgoyne RD, Haynes LP. Sense and specificity in neuronal calcium signalling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1921-32. [PMID: 25447549 PMCID: PMC4728190 DOI: 10.1016/j.bbamcr.2014.10.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 10/25/2014] [Accepted: 10/29/2014] [Indexed: 11/02/2022]
Abstract
Changes in the intracellular free calcium concentration ([Ca²⁺]i) in neurons regulate many and varied aspects of neuronal function over time scales from microseconds to days. The mystery is how a single signalling ion can lead to such diverse and specific changes in cell function. This is partly due to aspects of the Ca²⁺ signal itself, including its magnitude, duration, localisation and persistent or oscillatory nature. The transduction of the Ca²⁺ signal requires Ca²⁺binding to various Ca²⁺ sensor proteins. The different properties of these sensors are important for differential signal processing and determine the physiological specificity of Ca(2+) signalling pathways. A major factor underlying the specific roles of particular Ca²⁺ sensor proteins is the nature of their interaction with target proteins and how this mediates unique patterns of regulation. We review here recent progress from structural analyses and from functional analyses in model organisms that have begun to reveal the rules that underlie Ca²⁺ sensor protein specificity for target interaction. We discuss three case studies exemplifying different aspects of Ca²⁺ sensor/target interaction. This article is part of a special issue titled the 13th European Symposium on Calcium.
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Affiliation(s)
- Robert D Burgoyne
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, United Kingdom.
| | - Lee P Haynes
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, United Kingdom
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43
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Li C, Ames JB. ¹H, ¹³C, and ¹⁵N chemical shift assignments of neuronal calcium sensor protein, hippocalcin. BIOMOLECULAR NMR ASSIGNMENTS 2014; 8:63-6. [PMID: 23250791 PMCID: PMC3625700 DOI: 10.1007/s12104-012-9453-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 12/10/2012] [Indexed: 06/01/2023]
Abstract
Hippocalcin, a member of the neuronal calcium sensor (NCS) subclass of the calmodulin superfamily, serves as an important calcium sensor for the slow afterhyperpolarizing (sAHP) current in the hippocampus, which underlies some forms of learning and memory. Hippocalcin is also a calcium sensor for hippocampal long-term depression (LTD) and genetically linked to neurodegenerative diseases. We report NMR chemical shift assignments of Ca(2+)-free hippocalcin (BMRB no. 18627).
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Affiliation(s)
- Congmin Li
- Department of Chemistry, University of California, Davis, CA 95616
| | - James B. Ames
- Department of Chemistry, University of California, Davis, CA 95616
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Lim S, Dizhoor AM, Ames JB. Structural diversity of neuronal calcium sensor proteins and insights for activation of retinal guanylyl cyclase by GCAP1. Front Mol Neurosci 2014; 7:19. [PMID: 24672427 PMCID: PMC3956117 DOI: 10.3389/fnmol.2014.00019] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 02/27/2014] [Indexed: 01/08/2023] Open
Abstract
Neuronal calcium sensor (NCS) proteins, a sub-branch of the calmodulin superfamily, are expressed in the brain and retina where they transduce calcium signals and are genetically linked to degenerative diseases. The amino acid sequences of NCS proteins are highly conserved but their physiological functions are quite different. Retinal recoverin controls Ca2+-dependent inactivation of light-excited rhodopsin during phototransduction, guanylyl cyclase activating proteins 1 and 2 (GCAP1 and GCAP2) promote Ca2+-dependent activation of retinal guanylyl cyclases, and neuronal frequenin (NCS-1) modulates synaptic activity and neuronal secretion. Here we review the molecular structures of myristoylated forms of NCS-1, recoverin, and GCAP1 that all look very different, suggesting that the attached myristoyl group helps to refold these highly homologous proteins into different three-dimensional folds. Ca2+-binding to both recoverin and NCS-1 cause large protein conformational changes that ejects the covalently attached myristoyl group into the solvent exterior and promotes membrane targeting (Ca2+-myristoyl switch). The GCAP proteins undergo much smaller Ca2+-induced conformational changes and do not possess a Ca2+-myristoyl switch. Recent structures of GCAP1 in both its activator and Ca2+-bound inhibitory states will be discussed to understand structural determinants that control their Ca2+-dependent activation of retinal guanylyl cyclases.
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Affiliation(s)
- Sunghyuk Lim
- Department of Chemistry, University of California at Davis Davis, CA, USA
| | - Alexander M Dizhoor
- Basic Sciences, Pennsylvania College of Optometry, Salus University Elkins Park, PA, USA
| | - James B Ames
- Department of Chemistry, University of California at Davis Davis, CA, USA
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45
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Abstract
The sodium-potassium ATPase (i.e., the "sodium pump") plays a central role in maintaining ionic homeostasis in all cells. Although the sodium pump is intrinsically electrogenic and responsive to dynamic changes in intracellular sodium concentration, its role in regulating neuronal excitability remains unclear. Here we describe a physiological role for the sodium pump in regulating the excitability of mouse neocortical layer 5 and hippocampal CA1 pyramidal neurons. Trains of action potentials produced long-lasting (∼20 s) afterhyperpolarizations (AHPs) that were insensitive to blockade of voltage-gated calcium channels or chelation of intracellular calcium, but were blocked by tetrodotoxin, ouabain, or the removal of extracellular potassium. Correspondingly, the AHP time course was similar to the decay of activity-induced increases in intracellular sodium, whereas intracellular calcium decayed at much faster rates. To determine whether physiological patterns of activity engage the sodium pump, we replayed in vitro a place-specific burst of 15 action potentials recorded originally in vivo in a CA1 "place cell" as the animal traversed the associated place field. In both layer 5 and CA1 pyramidal neurons, this "place cell train" generated small, long-lasting AHPs capable of reducing neuronal excitability for many seconds. Place-cell-train-induced AHPs were blocked by ouabain or removal of extracellular potassium, but not by intracellular calcium chelation. Finally, we found calcium contributions to the AHP to be temperature dependent: prominent at room temperature, but largely absent at 35°C. Our results demonstrate a previously unappreciated role for the sodium-potassium ATPase in regulating the excitability of neocortical and hippocampal pyramidal neurons.
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46
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Myers WK, Xu X, Li C, Lagerstedt JO, Budamagunta MS, Voss JC, Britt RD, Ames JB. Double electron-electron resonance probes Ca²⁺-induced conformational changes and dimerization of recoverin. Biochemistry 2013; 52:5800-8. [PMID: 23906368 DOI: 10.1021/bi400538w] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recoverin, a member of the neuronal calcium sensor (NCS) branch of the calmodulin superfamily, is expressed in retinal photoreceptor cells and serves as a calcium sensor in vision. Ca²⁺-induced conformational changes in recoverin cause extrusion of its covalently attached myristate (termed Ca²⁺-myristoyl switch) that promotes translocation of recoverin to disk membranes during phototransduction in retinal rod cells. Here we report double electron-electron resonance (DEER) experiments on recoverin that probe Ca²⁺-induced changes in distance as measured by the dipolar coupling between spin-labels strategically positioned at engineered cysteine residues on the protein surface. The DEER distance between nitroxide spin-labels attached at C39 and N120C is 2.5 ± 0.1 nm for Ca²⁺-free recoverin and 3.7 ± 0.1 nm for Ca²⁺-bound recoverin. An additional DEER distance (5-6 nm) observed for Ca²⁺-bound recoverin may represent an intermolecular distance between C39 and N120. ¹⁵N NMR relaxation analysis and CW-EPR experiments both confirm that Ca²⁺-bound recoverin forms a dimer at protein concentrations above 100 μM, whereas Ca²⁺-free recoverin is monomeric. We propose that Ca²⁺-induced dimerization of recoverin at the disk membrane surface may play a role in regulating Ca²⁺-dependent phosphorylation of dimeric rhodopsin. The DEER approach will be useful for elucidating dimeric structures of NCS proteins in general for which Ca²⁺-induced dimerization is functionally important but not well understood.
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Affiliation(s)
- William K Myers
- Department of Chemistry, University of California, Davis, California 95616, United States
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47
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What determines the kinetics of the slow afterhyperpolarization (sAHP) in neurons? Biophys J 2013; 104:281-3. [PMID: 23442848 DOI: 10.1016/j.bpj.2012.11.3832] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 11/13/2012] [Accepted: 11/16/2012] [Indexed: 11/20/2022] Open
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48
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Buro C, Oliveira KC, Lu Z, Leutner S, Beckmann S, Dissous C, Cailliau K, Verjovski-Almeida S, Grevelding CG. Transcriptome analyses of inhibitor-treated schistosome females provide evidence for cooperating Src-kinase and TGFβ receptor pathways controlling mitosis and eggshell formation. PLoS Pathog 2013; 9:e1003448. [PMID: 23785292 PMCID: PMC3681755 DOI: 10.1371/journal.ppat.1003448] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 05/07/2013] [Indexed: 11/18/2022] Open
Abstract
Schistosome parasites cause schistosomiasis, one of the most prevalent parasitemias worldwide affecting humans and animals. Constant pairing of schistosomes is essential for female sexual maturation and egg production, which causes pathogenesis. Female maturation involves signaling pathways controlling mitosis and differentiation within the gonads. In vitro studies had shown before that a Src-specific inhibitor, Herbimycin A (Herb A), and a TGFβ receptor (TβR) inhibitor (TRIKI) have physiological effects such as suppressed mitoses and egg production in paired females. As one Herb A target, the gonad-specifically expressed Src kinase SmTK3 was identified. Here, we comparatively analyzed the transcriptome profiles of Herb A- and TRIKI-treated females identifying transcriptional targets of Src-kinase and TβRI pathways. After demonstrating that TRIKI inhibits the schistosome TGFβreceptor SmTβRI by kinase assays in Xenopus oocytes, couples were treated with Herb A, TRIKI, or both inhibitors simultaneously in vitro. RNA was isolated from females for microarray hybridizations and transcription analyses. The obtained data were evaluated by Gene Ontology (GO) and Ingenuity Pathway Analysis (IPA), but also by manual classification and intersection analyses. Finally, extensive qPCR experiments were done to verify differential transcription of candidate genes under inhibitor influence but also to functionally reinforce specific physiological effects. A number of genes found to be differentially regulated are associated with mitosis and differentiation. Among these were calcium-associated genes and eggshell-forming genes. In situ hybridization confirmed transcription of genes coding for the calcium sensor hippocalcin, the calcium transporter ORAI-1, and the calcium-binding protein calmodulin-4 in the reproductive system pointing to a role of calcium in parasite reproduction. Functional qPCR results confirmed an inhibitor-influenced, varying dependence of the transcriptional activities of Smp14, Smp48, fs800, a predicted eggshell precursor protein and SmTYR1. The results show that eggshell-formation is regulated by at least two pathways cooperatively operating in a balanced manner to control egg production. As one of the most prevalent parasitic infections worldwide, schistosomiasis is caused by blood-flukes of the genus Schistosoma. Pathology coincides with egg production, which is started upon pairing of the dioeciously living adults. A constant pairing contact is required to induce mitoses and differentiation processes in the female leading to the development of the gonads. Although long known, the molecular processes controlling gonad development or egg-production in schistosomes or other platyhelminths are largely unknown. Using an established in vitro-culture system and specific, chemical inhibitors we have obtained first evidence in previous studies for the participation of signal transduction processes playing essential roles in controlling mitoses, differentiation and egg production. In the present study we applied combinatory inhibitor treatments combined with subsequent microarray and qPCR analyses and demonstrate for the first time that cooperating Src-Kinase- und TGFβ-signaling pathways control mitoses and egg formation processes. Besides direct evidence for managing transcription of eggshell-forming genes, new target molecules of these pathways were identified. Among these are calcium-associated genes providing a first hint towards a role of this ion for reproduction. Our finding shed first light on the signaling mechanisms controlling egg formation, which is important for life-cycling and pathology.
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Affiliation(s)
- Christin Buro
- Institute of Parasitology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Katia C. Oliveira
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brasil
| | - Zhigang Lu
- Institute of Parasitology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Silke Leutner
- Institute of Parasitology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Svenja Beckmann
- Institute of Parasitology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Colette Dissous
- CIIL - Center of Infection and Immunity of Lille, Université Lille Nord de France, Inserm U1019, CNRS-UMR 8204, Institut Pasteur de Lille, Lille, France
| | - Katia Cailliau
- Laboratoire de Régulation des Signaux de Division, Université Lille 1 Sciences et Technology, EA 4479, IFR 147, Villeneuve d'Ascq, France
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Ford KJ, Arroyo DA, Kay JN, Lloyd EE, Bryan RM, Sanes JR, Feller MB. A role for TREK1 in generating the slow afterhyperpolarization in developing starburst amacrine cells. J Neurophysiol 2013; 109:2250-9. [PMID: 23390312 DOI: 10.1152/jn.01085.2012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Slow afterhyperpolarizations (sAHPs) play an important role in establishing the firing pattern of neurons that in turn influence network activity. sAHPs are mediated by calcium-activated potassium channels. However, the molecular identity of these channels and the mechanism linking calcium entry to their activation are still unknown. Here we present several lines of evidence suggesting that the sAHPs in developing starburst amacrine cells (SACs) are mediated by two-pore potassium channels. First, we use whole cell and perforated patch voltage clamp recordings to characterize the sAHP conductance under different pharmacological conditions. We find that this conductance was calcium dependent, reversed at EK, blocked by barium, insensitive to apamin and TEA, and activated by arachidonic acid. In addition, pharmacological inhibition of calcium-activated phosphodiesterase reduced the sAHP. Second, we performed gene profiling on isolated SACs and found that they showed strong preferential expression of the two-pore channel gene kcnk2 that encodes TREK1. Third, we demonstrated that TREK1 knockout animals exhibited an altered frequency of retinal waves, a frequency that is set by the sAHPs in SACs. With these results, we propose a model in which depolarization-induced decreases in cAMP lead to disinhibition of the two-pore potassium channels and in which the kinetics of this biochemical pathway dictate the slow activation and deactivation of the sAHP conductance. Our model offers a novel pathway for the activation of a conductance that is physiologically important.
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Affiliation(s)
- Kevin J Ford
- Department of Molecular and Cellular Biology, University of California, Berkeley, CA, USA
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Kim KS, Kobayashi M, Takamatsu K, Tzingounis AV. Hippocalcin and KCNQ channels contribute to the kinetics of the slow afterhyperpolarization. Biophys J 2012; 103:2446-54. [PMID: 23260046 DOI: 10.1016/j.bpj.2012.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 10/25/2012] [Accepted: 11/01/2012] [Indexed: 12/29/2022] Open
Abstract
The calcium-activated slow afterhyperpolarization (sAHP) is a potassium conductance implicated in many physiological functions of the brain including memory, aging, and epilepsy. In large part, the sAHP's importance stems from its exceedingly long-lasting time-course, which integrates action potential-induced calcium signals and allows the sAHP to control neuronal excitability and prevent runaway firing. Despite its role in neuronal physiology, the molecular mechanisms that give rise to its unique kinetics are, to our knowledge, still unknown. Recently, we identified KCNQ channels as a candidate potassium channel family that can contribute to the sAHP. Here, we test whether KCNQ channels shape the sAHP rise and decay kinetics in wild-type mice and mice lacking Hippocalcin, the putative sAHP calcium sensor. Application of retigabine to speed KCNQ channel activation accelerated the rise of the CA3 pyramidal neuron sAHP current in both wild-type and Hippocalcin knockout mice, indicating that the gating of KCNQ channels limits the sAHP activation. Interestingly, we found that the decay of the sAHP was prolonged in Hippocalcin knockout mice, and that the decay was sensitive to retigabine modulation, unlike in wild-type mice. Together, our results demonstrate that sAHP activation in CA3 pyramidal neurons is critically dependent on KCNQ channel kinetics whereas the identity of the sAHP calcium sensor determines whether KCNQ channel kinetics also limit the sAHP decay.
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Affiliation(s)
- Kwang S Kim
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
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