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Roelfs D, Frei O, van der Meer D, Tissink E, Shadrin A, Alnaes D, Andreassen OA, Westlye LT, Kaufmann T. Shared genetic architecture between mental health and the brain functional connectome in the UK Biobank. BMC Psychiatry 2023; 23:461. [PMID: 37353766 PMCID: PMC10290393 DOI: 10.1186/s12888-023-04905-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 05/26/2023] [Indexed: 06/25/2023] Open
Abstract
Psychiatric disorders are complex clinical conditions with large heterogeneity and overlap in symptoms, genetic liability and brain imaging abnormalities. Building on a dimensional conceptualization of mental health, previous studies have reported genetic overlap between psychiatric disorders and population-level mental health, and between psychiatric disorders and brain functional connectivity. Here, in 30,701 participants aged 45-82 from the UK Biobank we map the genetic associations between self-reported mental health and resting-state fMRI-based measures of brain network function. Multivariate Omnibus Statistical Test revealed 10 genetic loci associated with population-level mental symptoms. Next, conjunctional FDR identified 23 shared genetic variants between these symptom profiles and fMRI-based brain network measures. Functional annotation implicated genes involved in brain structure and function, in particular related to synaptic processes such as axonal growth (e.g. NGFR and RHOA). These findings provide further genetic evidence of an association between brain function and mental health traits in the population.
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Affiliation(s)
- Daniel Roelfs
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital & Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
| | - Oleksandr Frei
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital & Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Dennis van der Meer
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital & Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- School of Mental Health and Neuroscience, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Elleke Tissink
- Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam, 1081 HV, The Netherlands
| | - Alexey Shadrin
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital & Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Dag Alnaes
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital & Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Bjørknes College, Oslo, Norway
| | - Ole A Andreassen
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital & Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Lars T Westlye
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital & Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Psychology, University of Oslo, Oslo, Norway
| | - Tobias Kaufmann
- NORMENT Centre, Division of Mental Health and Addiction, Oslo University Hospital & Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
- Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health, University of Tübingen, Tübingen, Germany.
- German Center for Mental Health (DZPG), Tübingen, Germany.
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Kumar SS, Gänswein T, Buccino AP, Xue X, Bartram J, Emmenegger V, Hierlemann A. Tracking axon initial segment plasticity using high-density microelectrode arrays: A computational study. Front Neuroinform 2022; 16:957255. [PMID: 36221258 PMCID: PMC7613690 DOI: 10.3389/fninf.2022.957255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Despite being composed of highly plastic neurons with extensive positive feedback, the nervous system maintains stable overall function. To keep activity within bounds, it relies on a set of negative feedback mechanisms that can induce stabilizing adjustments and that are collectively termed “homeostatic plasticity.” Recently, a highly excitable microdomain, located at the proximal end of the axon—the axon initial segment (AIS)—was found to exhibit structural modifications in response to activity perturbations. Though AIS plasticity appears to serve a homeostatic purpose, many aspects governing its expression and its functional role in regulating neuronal excitability remain elusive. A central challenge in studying the phenomenon is the rich heterogeneity of its expression (distal/proximal relocation, shortening, lengthening) and the variability of its functional role. A potential solution is to track AISs of a large number of neurons over time and attempt to induce structural plasticity in them. To this end, a promising approach is to use extracellular electrophysiological readouts to track a large number of neurons at high spatiotemporal resolution by means of high-density microelectrode arrays (HD-MEAs). However, an analysis framework that reliably identifies specific activity signatures that uniquely map on to underlying microstructural changes is missing. In this study, we assessed the feasibility of such a task and used the distal relocation of the AIS as an exemplary problem. We used sophisticated computational models to systematically explore the relationship between incremental changes in AIS positions and the specific consequences observed in simulated extracellular field potentials. An ensemble of feature changes in the extracellular fields that reliably characterize AIS plasticity was identified. We trained models that could detect these signatures with remarkable accuracy. Based on these findings, we propose a hybrid analysis framework that could potentially enable high-throughput experimental studies of activity-dependent AIS plasticity using HD-MEAs.
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Di Re J, Hsu WCJ, Kayasandik CB, Fularczyk N, James TF, Nenov MN, Negi P, Marosi M, Scala F, Prasad S, Labate D, Laezza F. Inhibition of AKT Signaling Alters βIV Spectrin Distribution at the AIS and Increases Neuronal Excitability. Front Mol Neurosci 2021; 14:643860. [PMID: 34276302 PMCID: PMC8278006 DOI: 10.3389/fnmol.2021.643860] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 05/27/2021] [Indexed: 11/24/2022] Open
Abstract
The axon initial segment (AIS) is a highly regulated subcellular domain required for neuronal firing. Changes in the AIS protein composition and distribution are a form of structural plasticity, which powerfully regulates neuronal activity and may underlie several neuropsychiatric and neurodegenerative disorders. Despite its physiological and pathophysiological relevance, the signaling pathways mediating AIS protein distribution are still poorly studied. Here, we used confocal imaging and whole-cell patch clamp electrophysiology in primary hippocampal neurons to study how AIS protein composition and neuronal firing varied in response to selected kinase inhibitors targeting the AKT/GSK3 pathway, which has previously been shown to phosphorylate AIS proteins. Image-based features representing the cellular pattern distribution of the voltage-gated Na+ (Nav) channel, ankyrin G, βIV spectrin, and the cell-adhesion molecule neurofascin were analyzed, revealing βIV spectrin as the most sensitive AIS protein to AKT/GSK3 pathway inhibition. Within this pathway, inhibition of AKT by triciribine has the greatest effect on βIV spectrin localization to the AIS and its subcellular distribution within neurons, a phenotype that Support Vector Machine classification was able to accurately distinguish from control. Treatment with triciribine also resulted in increased excitability in primary hippocampal neurons. Thus, perturbations to signaling mechanisms within the AKT pathway contribute to changes in βIV spectrin distribution and neuronal firing that may be associated with neuropsychiatric and neurodegenerative disorders.
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Affiliation(s)
- Jessica Di Re
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Wei-Chun J. Hsu
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
- Biochemistry and Molecular Biology Graduate Program, Graduate School of Biomedical Sciences, University of Texas Medical Branch, Galveston, TX, United States
- M.D./Ph.D. Combined Degree Program, Graduate School of Biomedical Sciences, University of Texas Medical Branch, Galveston, TX, United States
| | - Cihan B. Kayasandik
- Department of Mathematics, University of Houston, Houston, TX, United States
- Department of Computer Engineering, Istanbul Medipol University, Istanbul, Turkey
| | - Nickolas Fularczyk
- Department of Mathematics, University of Houston, Houston, TX, United States
| | - T. F. James
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Miroslav N. Nenov
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Pooran Negi
- Department of Mathematics, University of Houston, Houston, TX, United States
| | - Mate Marosi
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Federico Scala
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Saurabh Prasad
- Department of Electrical and Computer Engineering, University of Houston, Houston, TX, United States
| | - Demetrio Labate
- Department of Mathematics, University of Houston, Houston, TX, United States
| | - Fernanda Laezza
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
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Wang P, Wadsworth PA, Dvorak NM, Singh AK, Chen H, Liu Z, Zhou R, Holthauzen LMF, Zhou J, Laezza F. Design, Synthesis, and Pharmacological Evaluation of Analogues Derived from the PLEV Tetrapeptide as Protein-Protein Interaction Modulators of Voltage-Gated Sodium Channel 1.6. J Med Chem 2020; 63:11522-11547. [PMID: 33054193 DOI: 10.1021/acs.jmedchem.0c00531] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The voltage-gated Na+ (Nav) channel is the molecular determinant of excitability. Disruption of protein-protein interactions (PPIs) between Nav1.6 and fibroblast growth factor 14 (FGF14) leads to impaired excitability of neurons in clinically relevant brain areas associated with channelopathies. Here, we designed, synthesized, and pharmacologically characterized new peptidomimetics based on a PLEV tetrapeptide scaffold derived from the FGF14:Nav1.6 PPI interface. Addition of an N-terminal 1-adamantanecarbonyl pharmacophore significantly improved peptidomimetic inhibitory potency. Surface plasmon resonance studies revealed that while this moiety was sufficient to confer binding to FGF14, altering the C-terminal moiety from methoxy (21a) to π bond-containing (23a and 23b) or cycloalkane substituents (23e) abrogated the binding to Nav1.6. Whole-cell patch-clamp electrophysiology subsequently revealed that 21a had functionally relevant interactions with both the C-terminal tail of Nav1.6 and FGF14. Collectively, these findings support that 21a (PW0564) may serve as a promising lead to develop target-selective neurotherapeutics by modulating protein-channel interactions.
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Wadsworth PA, Singh AK, Nguyen N, Dvorak NM, Tapia CM, Russell WK, Stephan C, Laezza F. JAK2 regulates Nav1.6 channel function via FGF14 Y158 phosphorylation. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2020; 1867:118786. [PMID: 32599005 PMCID: PMC7984254 DOI: 10.1016/j.bbamcr.2020.118786] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 06/18/2020] [Accepted: 06/20/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND Protein interactions between voltage-gated sodium (Nav) channels and accessory proteins play an essential role in neuronal firing and plasticity. However, a surprisingly limited number of kinases have been identified as regulators of these molecular complexes. We hypothesized that numerous as-of-yet unidentified kinases indirectly regulate the Nav channel via modulation of the intracellular fibroblast growth factor 14 (FGF14), an accessory protein with numerous unexplored phosphomotifs and required for channel function in neurons. METHODS Here we present results from an in-cell high-throughput screening (HTS) against the FGF14: Nav1.6 complex using >3000 diverse compounds targeting an extensive range of signaling pathways. Regulation by top kinase targets was then explored using in vitro phosphorylation, biophysics, mass-spectrometry and patch-clamp electrophysiology. RESULTS Compounds targeting Janus kinase 2 (JAK2) were over-represented among HTS hits. Phosphomotif scans supported by mass spectrometry revealed FGF14Y158, a site previously shown to mediate both FGF14 homodimerization and interactions with Nav1.6, as a JAK2 phosphorylation site. Following inhibition of JAK2, FGF14 homodimerization increased in a manner directly inverse to FGF14:Nav1.6 complex formation, but not in the presence of the FGF14Y158A mutant. Patch-clamp electrophysiology revealed that through Y158, JAK2 controls FGF14-dependent modulation of Nav1.6 channels. In hippocampal CA1 pyramidal neurons, the JAK2 inhibitor Fedratinib reduced firing by a mechanism that is dependent upon expression of FGF14. CONCLUSIONS These studies point toward a novel mechanism by which levels of JAK2 in neurons could directly influence firing and plasticity by controlling the FGF14 dimerization equilibrium, and thereby the availability of monomeric species for interaction with Nav1.6.
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Affiliation(s)
- Paul A Wadsworth
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX, USA; Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Aditya K Singh
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Nghi Nguyen
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, USA
| | - Nolan M Dvorak
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Cynthia M Tapia
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX, USA
| | - William K Russell
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Clifford Stephan
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, USA
| | - Fernanda Laezza
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX, USA; Center for Addiction Research, The University of Texas Medical Branch, Galveston, TX, USA.
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Sun J, Niu C, Ye W, An N, Chen G, Huang X, Wang J, Chen X, Shen Y, Huang S, Wang Y, Wang X, Wang Y, Jin L, Cong W, Li X. FGF13 Is a Novel Regulator of NF-κB and Potentiates Pathological Cardiac Hypertrophy. iScience 2020; 23:101627. [PMID: 33089113 PMCID: PMC7567043 DOI: 10.1016/j.isci.2020.101627] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 08/13/2020] [Accepted: 09/25/2020] [Indexed: 12/31/2022] Open
Abstract
FGF13 is an intracellular FGF factor. Its role in cardiomyopathies has been rarely investigated. We revealed that endogenous FGF13 is up-regulated in cardiac hypertrophy accompanied by increased nuclear localization. The upregulation of FGF13 plays a deteriorating role both in hypertrophic cardiomyocytes and mouse hearts. Mechanistically, FGF13 directly interacts with p65 by its nuclear localization sequence and co-localizes with p65 in the nucleus in cardiac hypertrophy. FGF13 deficiency inhibits NF-κB activation in ISO-treated NRCMs and TAC-surgery mouse hearts, whereas FGF13 overexpression shows the opposite trend. Moreover, FGF13 overexpression alone is sufficient to activate NF-κB in cardiomyocytes. The interaction between FGF13 and p65 or the effects of FGF13 on NF-κB have nothing to do with IκB. Together, an IκB-independent mechanism for NF-κB regulation has been revealed in cardiomyocytes both under basal and stressful conditions, suggesting the promising application of FGF13 as a therapeutic target for pathological cardiac hypertrophy and heart failure. Endogenous FGF13 is up-regulated in cardiomyocytes under pressure overload FGF13 directly interacts with p65 Forced FGF13 overexpression activates NF-κB in cardiomyocytes
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Affiliation(s)
- Jia Sun
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
| | - Chao Niu
- Pediatric Research Institute, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Weijian Ye
- Department of Pharmacy, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Ning An
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
| | - Gen Chen
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
| | - Xiaozhong Huang
- Department of Pediatric Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Jianan Wang
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
| | - Xixi Chen
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
| | - Yingjie Shen
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
| | - Shuai Huang
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
| | - Ying Wang
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
| | - Xu Wang
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
| | - Yang Wang
- Department of Histology and Embryology, Institute of Neuroscience, Wenzhou Medical University Wenzhou, 325000, China
| | - Litai Jin
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
| | - Weitao Cong
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
| | - Xiaokun Li
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325000, China
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7
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Lee M, Liu YC, Chen C, Lu CH, Lu ST, Huang TN, Hsu MT, Hsueh YP, Cheng PL. Ecm29-mediated proteasomal distribution modulates excitatory GABA responses in the developing brain. J Cell Biol 2020; 219:133566. [PMID: 31910261 PMCID: PMC7041676 DOI: 10.1083/jcb.201903033] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 10/14/2019] [Accepted: 11/13/2019] [Indexed: 12/31/2022] Open
Abstract
Neuronal GABAergic responses switch from excitatory to inhibitory at an early postnatal period in rodents. The timing of this switch is controlled by intracellular Cl− concentrations, but factors determining local levels of cation-chloride cotransporters remain elusive. Here, we report that local abundance of the chloride importer NKCC1 and timely emergence of GABAergic inhibition are modulated by proteasome distribution, which is mediated through interactions of proteasomes with the adaptor Ecm29 and the axon initial segment (AIS) scaffold protein ankyrin G. Mechanistically, both the Ecm29 N-terminal domain and an intact AIS structure are required for transport and tethering of proteasomes in the AIS region. In mice, Ecm29 knockout (KO) in neurons increases the density of NKCC1 protein in the AIS region, a change that positively correlates with a delay in the GABAergic response switch. Phenotypically, Ecm29 KO mice showed increased firing frequency of action potentials at early postnatal ages and were hypersusceptible to chemically induced convulsive seizures. Finally, Ecm29 KO neurons exhibited accelerated AIS developmental positioning, reflecting a perturbed AIS morphological plastic response to hyperexcitability arising from proteasome inhibition, a phenotype rescued by ectopic Ecm29 expression or NKCC1 inhibition. Together, our findings support the idea that neuronal maturation requires regulation of proteasomal distribution controlled by Ecm29.
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Affiliation(s)
- Min Lee
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yen-Chen Liu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Chen Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Chi-Huan Lu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Shao-Tzu Lu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Tzyy-Nan Huang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Meng-Tsung Hsu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Pei-Lin Cheng
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
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Di Re J, Kayasandik C, Botello-Lins G, Labate D, Laezza F. Imaging of the Axon Initial Segment. ACTA ACUST UNITED AC 2020; 89:e78. [PMID: 31532918 DOI: 10.1002/cpns.78] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The axon initial segment (AIS) is the first 20- to 60-μm segment of the axon proximal to the soma of a neuron. This highly specialized subcellular domain is the initiation site of the action potential and contains a high concentration of voltage-gated ion channels held in place by a complex nexus of scaffolding and regulatory proteins that ensure proper electrical activity of the neuron. Studies have shown that dysfunction of many AIS channels and scaffolding proteins occurs in a variety of neuropsychiatric and neurodegenerative diseases, raising the need to develop accurate methods for visualization and quantification of the AIS and its protein content in models of normal and disease conditions. In this article, we describe methods for immunolabeling AIS proteins in cultured neurons and brain slices as well as methods for quantifying protein expression and pattern distribution using fluorescent labeling of these proteins. © 2019 by John Wiley & Sons, Inc.
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Affiliation(s)
- Jessica Di Re
- Neuroscience Graduate Program, University of Texas Medical Branch, Galveston, Texas.,Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas
| | - Cihan Kayasandik
- Department of Computer Engineering, Istanbul Medipol University, Istanbul, Turkey
| | - Gonzalo Botello-Lins
- Biotechnology Program, Clear Falls High School, Clear Creek Independent School District, League City, Texas
| | - Demetrio Labate
- Department of Mathematics, University of Houston, Houston, Texas
| | - Fernanda Laezza
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas
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9
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Chagula DB, Rechciński T, Rudnicka K, Chmiela M. Ankyrins in human health and disease - an update of recent experimental findings. Arch Med Sci 2020; 16:715-726. [PMID: 32542072 PMCID: PMC7286341 DOI: 10.5114/aoms.2019.89836] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 02/25/2018] [Indexed: 12/17/2022] Open
Abstract
Ankyrins are adaptor molecules that in eukaryotic cells form complexes with ion channel proteins, cell adhesion and signalling molecules and components of the cytoskeleton. They play a pivotal role as scaffolding proteins, in the structural anchoring to the muscle membrane, in muscle development, neurogenesis and synapse formation. Dysfunction of ankyrins is implicated in numerous diseases such as hereditary spherocytosis, neurodegeneration of Purkinje cells, cardiac arrhythmia, Brugada syndrome, bipolar disorders and schizophrenia, congenital myopathies and congenital heart disease as well as cancers. Detecting either down- or over-expression of ankyrins and ergo their use as biomarkers can provide a new paradigm in the diagnosis of these diseases. This paper provides an outline of knowledge about the structure of ankyrins, and by making use of recent experimental research studies critically discusses their role in several health disorders. Moreover, therapeutic options utilizing engineered ankyrins, designed ankyrin repeat proteins (DARPins), are discussed.
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Affiliation(s)
- Damian B. Chagula
- Laboratory of Gastroimmunology, Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Tomasz Rechciński
- Department of Cardiology, Bieganski Regional Speciality Hospital, Medical University of Lodz, Lodz, Poland
| | - Karolina Rudnicka
- Laboratory of Gastroimmunology, Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Magdalena Chmiela
- Laboratory of Gastroimmunology, Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
- Corresponding author: Prof. Magdalena Chmiela Laboratory of Gastroimmunology, Department of Immmunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Lodz, 12/16 Banacha St, 90-237 Lodz, Poland, E-mail:
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10
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Wadsworth PA, Folorunso O, Nguyen N, Singh AK, D'Amico D, Powell RT, Brunell D, Allen J, Stephan C, Laezza F. High-throughput screening against protein:protein interaction interfaces reveals anti-cancer therapeutics as potent modulators of the voltage-gated Na + channel complex. Sci Rep 2019; 9:16890. [PMID: 31729429 PMCID: PMC6858373 DOI: 10.1038/s41598-019-53110-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 10/28/2019] [Indexed: 11/09/2022] Open
Abstract
Multiple voltage-gated Na+ (Nav) channelopathies can be ascribed to subtle changes in the Nav macromolecular complex. Fibroblast growth factor 14 (FGF14) is a functionally relevant component of the Nav1.6 channel complex, a causative link to spinocerebellar ataxia 27 (SCA27) and an emerging risk factor for neuropsychiatric disorders. Yet, how this protein:channel complex is regulated in the cell is still poorly understood. To search for key cellular pathways upstream of the FGF14:Nav1.6 complex, we have developed, miniaturized and optimized an in-cell assay in 384-well plates by stably reconstituting the FGF14:Nav1.6 complex using the split-luciferase complementation assay. We then conducted a high-throughput screening (HTS) of 267 FDA-approved compounds targeting known mediators of cellular signaling. Of the 65 hits initially detected, 24 were excluded based on counter-screening and cellular toxicity. Based on target analysis, potency and dose-response relationships, 5 compounds were subsequently repurchased for validation and confirmed as hits. Among those, the tyrosine kinase inhibitor lestaurtinib was highest ranked, exhibiting submicromolar inhibition of FGF14:Nav1.6 assembly. While providing evidence for a robust in-cell HTS platform that can be adapted to search for any channelopathy-associated regulatory proteins, these results lay the potential groundwork for repurposing cancer drugs for neuropsychopharmacology.
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Affiliation(s)
- Paul A Wadsworth
- MD/PhD Combined Degree Program and Biochemistry and Molecular Biology Graduate Program, The University of Texas Medical Branch, Galveston, Texas, 77555, USA.,Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, 77555, USA
| | - Oluwarotimi Folorunso
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, 77555, USA
| | - Nghi Nguyen
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, 77030, USA
| | - Aditya K Singh
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, 77555, USA
| | - Daniela D'Amico
- Neuroscience Graduate Program, The University of Texas Medical Branch, Galveston, Texas, 77555, USA
| | - Reid T Powell
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, 77030, USA
| | - David Brunell
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, 77030, USA
| | - John Allen
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, 77555, USA
| | - Clifford Stephan
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, 77030, USA
| | - Fernanda Laezza
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, 77555, USA.
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11
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Kim EJ, Feng C, Santamaria F, Kim JH. Impact of Auditory Experience on the Structural Plasticity of the AIS in the Mouse Brainstem Throughout the Lifespan. Front Cell Neurosci 2019; 13:456. [PMID: 31680869 PMCID: PMC6813928 DOI: 10.3389/fncel.2019.00456] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 09/25/2019] [Indexed: 12/18/2022] Open
Abstract
Sound input critically influences the development and maintenance of neuronal circuits in the mammalian brain throughout life. We investigate the structural and functional plasticity of auditory neurons in response to various auditory experiences during development, adulthood, and aging. Using electrophysiology, computer simulation, and immunohistochemistry, we study the structural plasticity of the axon initial segment (AIS) in the medial nucleus of the trapezoid body (MNTB) from the auditory brainstem of the mice (either sex), in different ages and auditory environments. The structure and spatial location of the AIS of MNTB neurons depend on their functional topographic location along the tonotopic axis, aligning high- to low-frequency sound-responding neurons (HF or LF neurons). HF neurons dramatically undergo structural remodeling of the AIS throughout life. The AIS progressively shortens during development, is stabilized in adulthood, and becomes longer in aging. Sound inputs are critically associated with setting and maintaining AIS plasticity and tonotopy at various ages. Sound stimulation increases the excitability of auditory neurons. Computer simulation shows that modification of the AIS length, location, and diameter can affect firing properties of MNTB neurons in the developing brainstem. The adaptive capability of axonal structure in response to various auditory experiences at different ages suggests that sound input is important for the development and maintenance of the structural and functional properties of the auditory brain throughout life.
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Affiliation(s)
- Eun Jung Kim
- The Department of Cellular and Integrative Physiology, UT Health San Antonio, San Antonio, TX, United States
| | - Chenling Feng
- The Department of Biology, University of Texas, San Antonio, TX, United States
| | - Fidel Santamaria
- The Department of Biology, University of Texas, San Antonio, TX, United States
| | - Jun Hee Kim
- The Department of Cellular and Integrative Physiology, UT Health San Antonio, San Antonio, TX, United States
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Axon initial segment plasticity accompanies enhanced excitation of visual cortical neurons in aged rats. Neuroreport 2019; 29:1537-1543. [PMID: 30320703 PMCID: PMC6250279 DOI: 10.1097/wnr.0000000000001145] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Recent studies have indicated that the structure of the axon initial segment (AIS) of neurons is highly plastic in response to changes in neuronal activity. Whether an age-related enhancement of neuronal responses in the visual cortex is coupled with plasticity of AISs is unknown. Here, we compare the AIS length and the distribution of Nav1.6, a key Na+ ion channel in action potential (AP) initiation, along the AIS of layer II/III neurons in the primary visual cortex (V1) of young adult and aged rats, which were examined previously in a single-unit recording study. In that study, we found that V1 neurons in aged rats showed a significantly higher spontaneous activity and stronger visually evoked responses than did neurons in young rats. Our present study shows that the mean AIS length of layer II/III neurons in the V1 area of aged rats was significantly shorter than that of young adult rats. Further, the proportion of AIS with the Nav1.6 distribution was also reduced significantly in aged rats relative to young rats, as indicated by a decrease in the mean Nav1.6 immunofluorescence optical density within AISs and a specific decrease in Nav1.6 immunofluorescence optical density near the proximal region of the AIS. Our results indicate that aging results in both shortening of AISs and reduction of Nav1.6 Na+ ion channel distribution along AISs, which accompanies enhanced neuronal activity. This age-related morphological plasticity may lower the AP amplitude by reducing Na+ ion entry during AP initiation, spare ATPs consumed by Na+ ion pumps during membrane potential restoration, and thus balance the energy expenditure caused by an increased firing rate of cortical neurons during the aging process.
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Sex-Specific Proteomic Changes Induced by Genetic Deletion of Fibroblast Growth Factor 14 (FGF14), a Regulator of Neuronal Ion Channels. Proteomes 2019; 7:proteomes7010005. [PMID: 30678040 PMCID: PMC6473632 DOI: 10.3390/proteomes7010005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/16/2019] [Accepted: 01/17/2019] [Indexed: 12/18/2022] Open
Abstract
Fibroblast growth factor 14 (FGF14) is a member of the intracellular FGFs, which is a group of proteins involved in neuronal ion channel regulation and synaptic transmission. We previously demonstrated that male Fgf14−/− mice recapitulate the salient endophenotypes of synaptic dysfunction and behaviors that are associated with schizophrenia (SZ). As the underlying etiology of SZ and its sex-specific onset remain elusive, the Fgf14−/− model may provide a valuable tool to interrogate pathways related to disease mechanisms. Here, we performed label-free quantitative proteomics to identify enriched pathways in both male and female hippocampi from Fgf14+/+ and Fgf14−/− mice. We discovered that all of the differentially expressed proteins measured in Fgf14−/− animals, relative to their same-sex wildtype counterparts, are associated with SZ based on genome-wide association data. In addition, measured changes in the proteome were predominantly sex-specific, with the male Fgf14−/− mice distinctly enriched for pathways associated with neuropsychiatric disorders. In the male Fgf14−/− mouse, we found molecular characteristics that, in part, may explain a previously described neurotransmission and behavioral phenotype. This includes decreased levels of ALDH1A1 and protein kinase A (PRKAR2B). ALDH1A1 has been shown to mediate an alternative pathway for gamma-aminobutyric acid (GABA) synthesis, while PRKAR2B is essential for dopamine 2 receptor signaling, which is the basis of current antipsychotics. Collectively, our results provide new insights in the role of FGF14 and support the use of the Fgf14−/− mouse as a useful preclinical model of SZ for generating hypotheses on disease mechanisms, sex-specific manifestation, and therapy.
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Elavl3 regulates neuronal polarity through the alternative splicing of an embryo-specific exon in AnkyrinG. Neurosci Res 2018; 135:13-20. [DOI: 10.1016/j.neures.2018.03.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/13/2018] [Accepted: 03/30/2018] [Indexed: 12/12/2022]
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Ali SR, Liu Z, Nenov MN, Folorunso O, Singh A, Scala F, Chen H, James TF, Alshammari M, Panova-Elektronova NI, White MA, Zhou J, Laezza F. Functional Modulation of Voltage-Gated Sodium Channels by a FGF14-Based Peptidomimetic. ACS Chem Neurosci 2018; 9:976-987. [PMID: 29359916 DOI: 10.1021/acschemneuro.7b00399] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Protein-protein interactions (PPI) offer unexploited opportunities for CNS drug discovery and neurochemical probe development. Here, we present ZL181, a novel peptidomimetic targeting the PPI interface of the voltage-gated Na+ channel Nav1.6 and its regulatory protein fibroblast growth factor 14 (FGF14). ZL181 binds to FGF14 and inhibits its interaction with the Nav1.6 channel C-tail. In HEK-Nav1.6 expressing cells, ZL181 acts synergistically with FGF14 to suppress Nav1.6 current density and to slow kinetics of fast inactivation, but antagonizes FGF14 modulation of steady-state inactivation that is regulated by the N-terminal tail of the protein. In medium spiny neurons in the nucleus accumbens, ZL181 suppresses excitability by a mechanism that is dependent upon expression of FGF14 and is consistent with a state-dependent inhibition of FGF14. Overall, ZL181 and derivatives could lay the ground for developing allosteric modulators of Nav channels that are of interest for a broad range of CNS disorders.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Musaad Alshammari
- King Saud University Graduate Studies Abroad Program, King Saud University, Riyadh, Saudi Arabia
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16
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The Axon Initial Segment: An Updated Viewpoint. J Neurosci 2018; 38:2135-2145. [PMID: 29378864 DOI: 10.1523/jneurosci.1922-17.2018] [Citation(s) in RCA: 162] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 01/20/2018] [Accepted: 01/25/2018] [Indexed: 12/20/2022] Open
Abstract
At the base of axons sits a unique compartment called the axon initial segment (AIS). The AIS generates and shapes the action potential before it is propagated along the axon. Neuronal excitability thus depends crucially on the AIS composition and position, and these adapt to developmental and physiological conditions. The AIS also demarcates the boundary between the somatodendritic and axonal compartments. Recent studies have brought insights into the molecular architecture of the AIS and how it regulates protein trafficking. This Viewpoints article summarizes current knowledge about the AIS and highlights future challenges in understanding this key actor of neuronal physiology.
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17
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Hsu WCJ, Wildburger NC, Haidacher SJ, Nenov MN, Folorunso O, Singh AK, Chesson BC, Franklin WF, Cortez I, Sadygov RG, Dineley KT, Rudra JS, Taglialatela G, Lichti CF, Denner L, Laezza F. PPARgamma agonists rescue increased phosphorylation of FGF14 at S226 in the Tg2576 mouse model of Alzheimer's disease. Exp Neurol 2017; 295:1-17. [PMID: 28522250 DOI: 10.1016/j.expneurol.2017.05.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 04/13/2017] [Accepted: 05/13/2017] [Indexed: 12/13/2022]
Abstract
BACKGROUND Cognitive impairment in humans with Alzheimer's disease (AD) and in animal models of Aβ-pathology can be ameliorated by treatments with the nuclear receptor peroxisome proliferator-activated receptor-gamma (PPARγ) agonists, such as rosiglitazone (RSG). Previously, we demonstrated that in the Tg2576 animal model of AD, RSG treatment rescued cognitive deficits and reduced aberrant activity of granule neurons in the dentate gyrus (DG), an area critical for memory formation. METHODS We used a combination of mass spectrometry, confocal imaging, electrophysiology and split-luciferase assay and in vitro phosphorylation and Ingenuity Pathway Analysis. RESULTS Using an unbiased, quantitative nano-LC-MS/MS screening, we searched for potential molecular targets of the RSG-dependent rescue of DG granule neurons. We found that S226 phosphorylation of fibroblast growth factor 14 (FGF14), an accessory protein of the voltage-gated Na+ (Nav) channels required for neuronal firing, was reduced in Tg2576 mice upon treatment with RSG. Using confocal microscopy, we confirmed that the Tg2576 condition decreased PanNav channels at the AIS of the DG, and that RSG treatment of Tg2576 mice reversed the reduction in PanNav channels. Analysis from previously published data sets identified correlative changes in action potential kinetics in RSG-treated T2576 compared to untreated and wildtype controls. In vitro phosphorylation and mass spectrometry confirmed that the multifunctional kinase GSK-3β, a downstream target of insulin signaling highly implicated in AD, phosphorylated FGF14 at S226. Assembly of the FGF14:Nav1.6 channel complex and functional regulation of Nav1.6-mediated currents by FGF14 was impaired by a phosphosilent S226A mutation. Bioinformatics pathway analysis of mass spectrometry and biochemistry data revealed a highly interconnected network encompassing PPARγ, FGF14, SCN8A (Nav 1.6), and the kinases GSK-3 β, casein kinase 2β, and ERK1/2. CONCLUSIONS These results identify FGF14 as a potential PPARγ-sensitive target controlling Aβ-induced dysfunctions of neuronal activity in the DG underlying memory loss in early AD.
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Affiliation(s)
- Wei-Chun J Hsu
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Biochemistry and Molecular Biology Graduate Program, Graduate School of Biomedical Sciences, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; M.D./Ph.D. Combined Degree Program, Graduate School of Biomedical Sciences, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Norelle C Wildburger
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Neuroscience Graduate Program, Graduate School of Biomedical Sciences, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Department of Neurology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, United States
| | - Sigmund J Haidacher
- Department of Internal Medicine, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Miroslav N Nenov
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Oluwarotimi Folorunso
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Aditya K Singh
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Brent C Chesson
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Whitney F Franklin
- Neuroscience Graduate Program, Graduate School of Biomedical Sciences, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Department of Neurology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Ibdanelo Cortez
- Neuroscience Graduate Program, Graduate School of Biomedical Sciences, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Rovshan G Sadygov
- Biochemistry and Molecular Biology Graduate Program, Graduate School of Biomedical Sciences, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Sealy Center for Molecular Medicine, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Kelly T Dineley
- Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Department of Neurology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Center for Addiction Research, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Jay S Rudra
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Giulio Taglialatela
- Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Department of Neurology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Cheryl F Lichti
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Larry Denner
- Sealy Center for Molecular Medicine, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Department of Internal Medicine, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Center for Addiction Research, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States
| | - Fernanda Laezza
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Center for Addiction Research, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States; Center for Biomedical Engineering, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, United States.
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18
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Di Re J, Wadsworth PA, Laezza F. Intracellular Fibroblast Growth Factor 14: Emerging Risk Factor for Brain Disorders. Front Cell Neurosci 2017; 11:103. [PMID: 28469558 PMCID: PMC5396478 DOI: 10.3389/fncel.2017.00103] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/28/2017] [Indexed: 01/31/2023] Open
Abstract
The finely tuned regulation of neuronal firing relies on the integrity of ion channel macromolecular complexes. Minimal disturbances of these tightly regulated networks can lead to persistent maladaptive plasticity of brain circuitry. The intracellular fibroblast growth factor 14 (FGF14) belongs to the nexus of proteins interacting with voltage-gated Na+ (Nav) channels at the axonal initial segment. Through isoform-specific interactions with the intracellular C-terminal tail of neuronal Nav channels (Nav1.1, Nav1.2, Nav1.6), FGF14 controls channel gating, axonal targeting and phosphorylation in neurons effecting excitability. FGF14 has been also involved in synaptic transmission, plasticity and neurogenesis in the cortico-mesolimbic circuit with cognitive and affective behavioral outcomes. In translational studies, interest in FGF14 continues to rise with a growing list of associative links to diseases of the cognitive and affective domains such as neurodegeneration, depression, anxiety, addictive behaviors and recently schizophrenia, suggesting its role as a converging node in the etiology of complex brain disorders. Yet, a full understanding of FGF14 function in neurons is far from being complete and likely to involve other functions unrelated to the direct regulation of Nav channels. The goal of this Mini Review article is to provide a summary of studies on the emerging role of FGF14 in complex brain disorders.
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Affiliation(s)
- Jessica Di Re
- Neuroscience Graduate Program, University of Texas Medical BranchGalveston, TX, USA.,Department of Pharmacology and Toxicology, University of Texas Medical BranchGalveston, TX, USA
| | - Paul A Wadsworth
- Biochemistry and Molecular Biology Graduate Program, The University of Texas Medical BranchGalveston, TX, USA
| | - Fernanda Laezza
- Department of Pharmacology and Toxicology, University of Texas Medical BranchGalveston, TX, USA.,Mitchell Center for Neurodegenerative Diseases, The University of Texas Medical BranchGalveston, TX, USA.,Center for Addiction Research, The University of Texas Medical BranchGalveston, TX, USA
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19
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NF-κB regulates neuronal ankyrin-G via a negative feedback loop. Sci Rep 2017; 7:42006. [PMID: 28181483 PMCID: PMC5299403 DOI: 10.1038/srep42006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 01/05/2017] [Indexed: 12/13/2022] Open
Abstract
The axon initial segment (AIS) is a neuronal compartment defined by ankyrin-G expression. We here demonstrate that the IKK-complex co-localizes and interacts with the cytoskeletal anchor protein ankyrin-G in immunoprecipitation and proximity-ligation experiments in cortical neurons. Overexpression of the 270 kDa variant of ankyrin-G suppressed, while gene-silencing of ankyrin-G expression increased nuclear factor-κB (NF-κB) activity in primary neurons, suggesting that ankyrin-G sequesters the transcription factor in the AIS. We also found that p65 bound to the ank3 (ankyrin-G) promoter sequence in chromatin immunoprecipitation analyses thereby increasing ank3 expression and ankyrin-G levels at the AIS. Gene-silencing of p65 or ankyrin-G overexpression suppressed ank3 reporter activity. Collectively these data demonstrate that p65/NF-κB controls ankyrin-G levels via a negative feedback loop, thereby linking NF-κB signaling with neuronal polarity and axonal plasticity.
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20
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Alshammari TK, Alshammari MA, Nenov MN, Hoxha E, Cambiaghi M, Marcinno A, James TF, Singh P, Labate D, Li J, Meltzer HY, Sacchetti B, Tempia F, Laezza F. Genetic deletion of fibroblast growth factor 14 recapitulates phenotypic alterations underlying cognitive impairment associated with schizophrenia. Transl Psychiatry 2016; 6:e806. [PMID: 27163207 PMCID: PMC5070049 DOI: 10.1038/tp.2016.66] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 02/25/2016] [Accepted: 03/05/2016] [Indexed: 12/14/2022] Open
Abstract
Cognitive processing is highly dependent on the functional integrity of gamma-amino-butyric acid (GABA) interneurons in the brain. These cells regulate excitability and synaptic plasticity of principal neurons balancing the excitatory/inhibitory tone of cortical networks. Reduced function of parvalbumin (PV) interneurons and disruption of GABAergic synapses in the cortical circuitry result in desynchronized network activity associated with cognitive impairment across many psychiatric disorders, including schizophrenia. However, the mechanisms underlying these complex phenotypes are still poorly understood. Here we show that in animal models, genetic deletion of fibroblast growth factor 14 (Fgf14), a regulator of neuronal excitability and synaptic transmission, leads to loss of PV interneurons in the CA1 hippocampal region, a critical area for cognitive function. Strikingly, this cellular phenotype associates with decreased expression of glutamic acid decarboxylase 67 (GAD67) and vesicular GABA transporter (VGAT) and also coincides with disrupted CA1 inhibitory circuitry, reduced in vivo gamma frequency oscillations and impaired working memory. Bioinformatics analysis of schizophrenia transcriptomics revealed functional co-clustering of FGF14 and genes enriched within the GABAergic pathway along with correlatively decreased expression of FGF14, PVALB, GAD67 and VGAT in the disease context. These results indicate that Fgf14(-/-) mice recapitulate salient molecular, cellular, functional and behavioral features associated with human cognitive impairment, and FGF14 loss of function might be associated with the biology of complex brain disorders such as schizophrenia.
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Affiliation(s)
- T K Alshammari
- Pharmacology and Toxicology Graduate Program, University of Texas Medical Branch, Galveston, TX, USA
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
- King Saud University Graduate Studies Abroad Program, King Saud University, Riyadh, Saudi Arabia
| | - M A Alshammari
- Pharmacology and Toxicology Graduate Program, University of Texas Medical Branch, Galveston, TX, USA
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
- King Saud University Graduate Studies Abroad Program, King Saud University, Riyadh, Saudi Arabia
| | - M N Nenov
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | - E Hoxha
- Neuroscience Institute Cavalieri Ottolenghi, Turin, Italy
- Department of Neuroscience, University of Torino, Turin, Italy
| | - M Cambiaghi
- Department of Neuroscience, University of Torino, Turin, Italy
| | - A Marcinno
- Neuroscience Institute Cavalieri Ottolenghi, Turin, Italy
| | - T F James
- Department of Neuroscience, University of Torino, Turin, Italy
| | - P Singh
- Department of Mathematics, University of Houston, Houston, TX, USA
| | - D Labate
- Department of Mathematics, University of Houston, Houston, TX, USA
| | - J Li
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Mitchell Center for Neurodegenerative Diseases, The University of Texas Medical Branch, Galveston, TX, USA
| | - H Y Meltzer
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - B Sacchetti
- Department of Neuroscience, University of Torino, Turin, Italy
| | - F Tempia
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
- Neuroscience Institute Cavalieri Ottolenghi, Turin, Italy
- Department of Neuroscience, University of Torino, Turin, Italy
| | - F Laezza
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
- Mitchell Center for Neurodegenerative Diseases, The University of Texas Medical Branch, Galveston, TX, USA
- Center for Addiction Research, The University of Texas Medical Branch, Galveston, TX, USA
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA. E-mail:
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Alshammari MA, Alshammari TK, Laezza F. Improved Methods for Fluorescence Microscopy Detection of Macromolecules at the Axon Initial Segment. Front Cell Neurosci 2016; 10:5. [PMID: 26909021 PMCID: PMC4754416 DOI: 10.3389/fncel.2016.00005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 01/11/2016] [Indexed: 11/13/2022] Open
Abstract
The axonal initial segment (AIS) is the subcellular compartment required for initiation of the action potential in neurons. Scaffolding and regulatory proteins at the AIS cluster with ion channels ensuring the integrity of electrical signaling. Interference with the configuration of this protein network can lead to profound effects on neuronal polarity, excitability, cell-to-cell connectivity and brain circuit plasticity. As such, the ability to visualize AIS components with precision provides an invaluable opportunity for parsing out key molecular determinants of neuronal function. Fluorescence-based immunolabeling is a sensitive method for morphological and molecular characterization of fine structures in neurons. Yet, even when combined with confocal microscopy, detection of AIS elements with immunofluorescence has been limited by the loss of antigenicity caused by fixative materials. This technical barrier has posed significant limitations in detecting AIS components alone or in combination with other markers. Here, we designed improved protocols targeted to confocal immunofluorescence detection of the AIS marker fibroblast growth factor 14 (FGF14) in combination with the cytoskeletal-associated protein Ankyrin-G, the scaffolding protein βIV-spectrin, voltage-gated Na+ (Nav) channels (especially the Nav1.6 isoform) and critical cell type-specific neuronal markers such as parvalbumin, calbindin, and NeuN in the mouse brain. Notably, we demonstrate that intracardiac perfusion of animals with a commercially available solution containing 1% formaldehyde and 0.5% methanol, followed by brief fixation with cold acetone is an optimal and sensitive protocol for FGF14 and other AIS marker detection that guarantees excellent tissue integrity. With variations in the procedure, we also significantly improved the detection of Nav1.6, a Nav isoform known for its fixative-sensitivity. Overall, this study provides an ensemble of immunohistochemical recipes that permit excellent staining of otherwise invisible molecules within well-preserved tissue architecture. While improving the specific investigation of AIS physiology and cell biology, our thorough study can also serve as a roadmap for optimizing immunodetection of other fixative-sensitive proteins expanding the repertoire of enabling methods for brain studies.
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Affiliation(s)
- Musaad A Alshammari
- Graduate Studies Abroad Program, King Saud UniversityRiyadh, Saudi Arabia; Department of Pharmacology and Toxicology, University of Texas Medical BranchGalveston, TX, USA
| | - Tahani K Alshammari
- Graduate Studies Abroad Program, King Saud UniversityRiyadh, Saudi Arabia; Department of Pharmacology and Toxicology, University of Texas Medical BranchGalveston, TX, USA
| | - Fernanda Laezza
- Department of Pharmacology and Toxicology, University of Texas Medical BranchGalveston, TX, USA; Mitchell Center for Neurodegenerative Diseases, University of Texas Medical BranchGalveston, TX, USA; Center for Addiction Research, University of Texas Medical BranchGalveston, TX, USA; Center for Biomedical Engineering, University of Texas Medical BranchGalveston, TX, USA
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23
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Alshammari MA, Alshammari TK, Nenov MN, Scala F, Laezza F. Fibroblast Growth Factor 14 Modulates the Neurogenesis of Granule Neurons in the Adult Dentate Gyrus. Mol Neurobiol 2015; 53:7254-7270. [PMID: 26687232 DOI: 10.1007/s12035-015-9568-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 11/29/2015] [Indexed: 11/25/2022]
Abstract
Adult neurogenesis, the production of mature neurons from progenitor cells in the adult mammalian brain, is linked to the etiology of neurodegenerative and psychiatric disorders. However, a thorough understanding of the molecular elements at the base of adult neurogenesis remains elusive. Here, we provide evidence for a previously undescribed function of fibroblast growth factor 14 (FGF14), a brain disease-associated factor that controls neuronal excitability and synaptic plasticity, in regulating adult neurogenesis in the dentate gyrus (DG). We found that FGF14 is dynamically expressed in restricted subtypes of sex determining region Y-box 2 (Sox2)-positive and doublecortin (DCX)-positive neural progenitors in the DG. Bromodeoxyuridine (BrdU) incorporation studies and confocal imaging revealed that genetic deletion of Fgf14 in Fgf14 -/- mice leads to a significant change in the proportion of proliferating and immature and mature newly born adult granule cells. This results in an increase in the late immature and early mature population of DCX and calretinin (CR)-positive neurons. Electrophysiological extracellular field recordings showed reduced minimal threshold response and impaired paired-pulse facilitation at the perforant path to DG inputs in Fgf14 -/- compared to Fgf14 +/+ mice, supporting disrupted synaptic connectivity as a correlative read-out to impaired neurogenesis. These new insights into the biology of FGF14 in neurogenesis shed light into the signaling pathways associated with disrupted functions in complex brain diseases.
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Affiliation(s)
- Musaad A Alshammari
- Pharmacology and Toxicology Graduate Program, The University of Texas Medical Branch, Galveston, TX, USA
- Graduate Studies Abroad Program, King Saud University, Riyadh, Saudi Arabia
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Medical Research Building 7.102B, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Tahani K Alshammari
- Pharmacology and Toxicology Graduate Program, The University of Texas Medical Branch, Galveston, TX, USA
- Graduate Studies Abroad Program, King Saud University, Riyadh, Saudi Arabia
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Medical Research Building 7.102B, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Miroslav N Nenov
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Medical Research Building 7.102B, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Federico Scala
- Biophysics Graduate Program, Institute of Human Physiology, Università Cattolica, Rome, Italy
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Medical Research Building 7.102B, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Fernanda Laezza
- Mitchell Center for Neurodegenerative Diseases, The University of Texas Medical Branch, Galveston, TX, USA.
- Center for Addiction Research, The University of Texas Medical Branch, Galveston, TX, USA.
- Center for Biomedical Engineering, The University of Texas Medical Branch, Galveston, TX, USA.
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Medical Research Building 7.102B, 301 University Boulevard, Galveston, TX, 77555, USA.
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24
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Tempia F, Hoxha E, Negro G, Alshammari MA, Alshammari TK, Panova-Elektronova N, Laezza F. Parallel fiber to Purkinje cell synaptic impairment in a mouse model of spinocerebellar ataxia type 27. Front Cell Neurosci 2015; 9:205. [PMID: 26089778 PMCID: PMC4455242 DOI: 10.3389/fncel.2015.00205] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/11/2015] [Indexed: 11/13/2022] Open
Abstract
Genetically inherited mutations in the fibroblast growth factor 14 (FGF14) gene lead to spinocerebellar ataxia type 27 (SCA27), an autosomal dominant disorder characterized by heterogeneous motor and cognitive impairments. Consistently, genetic deletion of Fgf14 in Fgf14 (-/-) mice recapitulates salient features of the SCA27 human disease. In vitro molecular studies in cultured neurons indicate that the FGF14 (F145S) SCA27 allele acts as a dominant negative mutant suppressing the FGF14 wild type function and resulting in inhibition of voltage-gated Na(+) and Ca(2+) channels. To gain insights in the cerebellar deficits in the animal model of the human disease, we applied whole-cell voltage-clamp in the acute cerebellar slice preparation to examine the properties of parallel fibers (PF) to Purkinje neuron synapses in Fgf14 (-/-) mice and wild type littermates. We found that the AMPA receptor-mediated excitatory postsynaptic currents evoked by PF stimulation (PF-EPSCs) were significantly reduced in Fgf14 (-/-) animals, while short-term plasticity, measured as paired-pulse facilitation (PPF), was enhanced. Measuring Sr(2+)-induced release of quanta from stimulated synapses, we found that the size of the PF-EPSCs was unchanged, ruling out a postsynaptic deficit. This phenotype was corroborated by decreased expression of VGLUT1, a specific presynaptic marker at PF-Purkinje neuron synapses. We next examined the mGluR1 receptor-induced response (mGluR1-EPSC) that under normal conditions requires a gradual build-up of glutamate concentration in the synaptic cleft, and found no changes in these responses in Fgf14 (-/-) mice. These results provide evidence of a critical role of FGF14 in maintaining presynaptic function at PF-Purkinje neuron synapses highlighting critical target mechanisms to recapitulate the complexity of the SCA27 disease.
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Affiliation(s)
- Filippo Tempia
- Department of Pharmacology and Toxicology, University of Texas Medical Branch Galveston, TX, USA ; Department of Neuroscience, University of Torino Torino, Italy ; Neuroscience Institute Cavalieri Ottolenghi Torino, Italy ; National Institute of Neuroscience-Torino Italy
| | - Eriola Hoxha
- Department of Neuroscience, University of Torino Torino, Italy ; Neuroscience Institute Cavalieri Ottolenghi Torino, Italy
| | - Giulia Negro
- Neuroscience Institute Cavalieri Ottolenghi Torino, Italy
| | - Musaad A Alshammari
- Department of Pharmacology and Toxicology, University of Texas Medical Branch Galveston, TX, USA ; Pharmacology and Toxicology Graduate Program, University of Texas Medical Branch Galveston, Texas, USA ; King Saud University Graduate Studies Abroad Program Riyadh, Saudi Arabia
| | - Tahani K Alshammari
- Department of Pharmacology and Toxicology, University of Texas Medical Branch Galveston, TX, USA ; Pharmacology and Toxicology Graduate Program, University of Texas Medical Branch Galveston, Texas, USA ; King Saud University Graduate Studies Abroad Program Riyadh, Saudi Arabia
| | - Neli Panova-Elektronova
- Department of Pharmacology and Toxicology, University of Texas Medical Branch Galveston, TX, USA
| | - Fernanda Laezza
- Department of Pharmacology and Toxicology, University of Texas Medical Branch Galveston, TX, USA ; Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch Galveston, TX, USA ; Center for Addiction Research, University of Texas Medical Branch Galveston, TX, USA ; Center for Biomedical Engineering, University of Texas Medical Branch Galveston, TX, USA
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25
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Ornitz DM, Itoh N. The Fibroblast Growth Factor signaling pathway. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2015; 4:215-66. [PMID: 25772309 PMCID: PMC4393358 DOI: 10.1002/wdev.176] [Citation(s) in RCA: 1315] [Impact Index Per Article: 146.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 11/23/2014] [Accepted: 01/08/2015] [Indexed: 12/13/2022]
Abstract
The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs). Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins. Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways. Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels. Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning. FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactivating developmental signaling pathways. Consistent with the presence of FGFs in almost all tissues and organs, aberrant activity of the pathway is associated with developmental defects that disrupt organogenesis, impair the response to injury, and result in metabolic disorders, and cancer. For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- David M Ornitz
- Department of Developmental Biology, Washington University School of MedicineSt. Louis, MO, USA
- *
Correspondence to:
| | - Nobuyuki Itoh
- Graduate School of Pharmaceutical Sciences, Kyoto UniversitySakyo, Kyoto, Japan
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26
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Wildburger NC, Ali SR, Hsu WCJ, Shavkunov AS, Nenov MN, Lichti CF, LeDuc RD, Mostovenko E, Panova-Elektronova NI, Emmett MR, Nilsson CL, Laezza F. Quantitative proteomics reveals protein-protein interactions with fibroblast growth factor 12 as a component of the voltage-gated sodium channel 1.2 (nav1.2) macromolecular complex in Mammalian brain. Mol Cell Proteomics 2015; 14:1288-300. [PMID: 25724910 PMCID: PMC4424400 DOI: 10.1074/mcp.m114.040055] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (Nav1.1–Nav1.9) are responsible for the initiation and propagation of action potentials in neurons, controlling firing patterns, synaptic transmission and plasticity of the brain circuit. Yet, it is the protein–protein interactions of the macromolecular complex that exert diverse modulatory actions on the channel, dictating its ultimate functional outcome. Despite the fundamental role of Nav channels in the brain, information on its proteome is still lacking. Here we used affinity purification from crude membrane extracts of whole brain followed by quantitative high-resolution mass spectrometry to resolve the identity of Nav1.2 protein interactors. Of the identified putative protein interactors, fibroblast growth factor 12 (FGF12), a member of the nonsecreted intracellular FGF family, exhibited 30-fold enrichment in Nav1.2 purifications compared with other identified proteins. Using confocal microscopy, we visualized native FGF12 in the brain tissue and confirmed that FGF12 forms a complex with Nav1.2 channels at the axonal initial segment, the subcellular specialized domain of neurons required for action potential initiation. Co-immunoprecipitation studies in a heterologous expression system validate Nav1.2 and FGF12 as interactors, whereas patch-clamp electrophysiology reveals that FGF12 acts synergistically with CaMKII, a known kinase regulator of Nav channels, to modulate Nav1.2-encoded currents. In the presence of CaMKII inhibitors we found that FGF12 produces a bidirectional shift in the voltage-dependence of activation (more depolarized) and the steady-state inactivation (more hyperpolarized) of Nav1.2, increasing the channel availability. Although providing the first characterization of the Nav1.2 CNS proteome, we identify FGF12 as a new functionally relevant interactor. Our studies will provide invaluable information to parse out the molecular determinant underlying neuronal excitability and plasticity, and extending the relevance of iFGFs signaling in the normal and diseased brain.
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Affiliation(s)
- Norelle C Wildburger
- From the ‡Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, 77555-0617; §Neuroscience Graduate Program, Graduate School of Biomedical Sciences, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas, 77555-0617; ¶UTMB Cancer Center, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas, 77555-1074;
| | - Syed R Ali
- From the ‡Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, 77555-0617
| | - Wei-Chun J Hsu
- ‖Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas, 77555-0617
| | - Alexander S Shavkunov
- From the ‡Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, 77555-0617; ¶UTMB Cancer Center, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas, 77555-1074
| | - Miroslav N Nenov
- From the ‡Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, 77555-0617
| | - Cheryl F Lichti
- From the ‡Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, 77555-0617; ¶UTMB Cancer Center, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas, 77555-1074
| | - Richard D LeDuc
- **National Center for Genome Analysis Support, Indiana University, 107 S Indiana Ave., Bloomington, Indiana, 47408
| | - Ekaterina Mostovenko
- From the ‡Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, 77555-0617; ¶UTMB Cancer Center, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas, 77555-1074
| | - Neli I Panova-Elektronova
- From the ‡Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, 77555-0617
| | - Mark R Emmett
- ¶UTMB Cancer Center, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas, 77555-1074; ‖Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas, 77555-0617
| | - Carol L Nilsson
- From the ‡Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, 77555-0617; ¶UTMB Cancer Center, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas, 77555-1074
| | - Fernanda Laezza
- From the ‡Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd, Galveston, Texas, 77555-0617;
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27
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Identifying a kinase network regulating FGF14:Nav1.6 complex assembly using split-luciferase complementation. PLoS One 2015; 10:e0117246. [PMID: 25659151 PMCID: PMC4319734 DOI: 10.1371/journal.pone.0117246] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 12/22/2014] [Indexed: 12/31/2022] Open
Abstract
Kinases play fundamental roles in the brain. Through complex signaling pathways, kinases regulate the strength of protein:protein interactions (PPI) influencing cell cycle, signal transduction, and electrical activity of neurons. Changes induced by kinases on neuronal excitability, synaptic plasticity and brain connectivity are linked to complex brain disorders, but the molecular mechanisms underlying these cellular events remain for the most part elusive. To further our understanding of brain disease, new methods for rapidly surveying kinase pathways in the cellular context are needed. The bioluminescence-based luciferase complementation assay (LCA) is a powerful, versatile toolkit for the exploration of PPI. LCA relies on the complementation of two firefly luciferase protein fragments that are functionally reconstituted into the full luciferase enzyme by two interacting binding partners. Here, we applied LCA in live cells to assay 12 kinase pathways as regulators of the PPI complex formed by the voltage-gated sodium channel, Nav1.6, a transmembrane ion channel that elicits the action potential in neurons and mediates synaptic transmission, and its multivalent accessory protein, the fibroblast growth factor 14 (FGF14). Through extensive dose-dependent validations of structurally-diverse kinase inhibitors and hierarchical clustering, we identified the PI3K/Akt pathway, the cell-cycle regulator Wee1 kinase, and protein kinase C (PKC) as prospective regulatory nodes of neuronal excitability through modulation of the FGF14:Nav1.6 complex. Ingenuity Pathway Analysis shows convergence of these pathways on glycogen synthase kinase 3 (GSK3) and functional assays demonstrate that inhibition of GSK3 impairs excitability of hippocampal neurons. This combined approach provides a versatile toolkit for rapidly surveying PPI signaling, allowing the discovery of new modular pathways centered on GSK3 that might be the basis for functional alterations between the normal and diseased brain.
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28
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James TF, Nenov MN, Wildburger NC, Lichti CF, Luisi J, Vergara F, Panova-Electronova NI, Nilsson CL, Rudra JS, Green TA, Labate D, Laezza F. The Nav1.2 channel is regulated by GSK3. Biochim Biophys Acta Gen Subj 2015; 1850:832-44. [PMID: 25615535 DOI: 10.1016/j.bbagen.2015.01.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 12/17/2014] [Accepted: 01/14/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND Phosphorylation plays an essential role in regulating voltage-gated sodium (Na(v)) channels and excitability. Yet, a surprisingly limited number of kinases have been identified as regulators of Na(v) channels. We posited that glycogen synthase kinase 3 (GSK3), a critical kinase found associated with numerous brain disorders, might directly regulate neuronal Na(v) channels. METHODS We used patch-clamp electrophysiology to record sodium currents from Na(v)1.2 channels stably expressed in HEK-293 cells. mRNA and protein levels were quantified with RT-PCR, Western blot, or confocal microscopy, and in vitro phosphorylation and mass spectrometry to identify phosphorylated residues. RESULTS We found that exposure of cells to GSK3 inhibitor XIII significantly potentiates the peak current density of Na(v)1.2, a phenotype reproduced by silencing GSK3 with siRNA. Contrarily, overexpression of GSK3β suppressed Na(v)1.2-encoded currents. Neither mRNA nor total protein expression was changed upon GSK3 inhibition. Cell surface labeling of CD4-chimeric constructs expressing intracellular domains of the Na(v)1.2 channel indicates that cell surface expression of CD4-Na(v)1.2 C-tail was up-regulated upon pharmacological inhibition of GSK3, resulting in an increase of surface puncta at the plasma membrane. Finally, using in vitro phosphorylation in combination with high resolution mass spectrometry, we further demonstrate that GSK3β phosphorylates T(1966) at the C-terminal tail of Na(v)1.2. CONCLUSION These findings provide evidence for a new mechanism by which GSK3 modulates Na(v) channel function via its C-terminal tail. GENERAL SIGNIFICANCE These findings provide fundamental knowledge in understanding signaling dysfunction common in several neuropsychiatric disorders.
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Affiliation(s)
- Thomas F James
- Department of Pharmacology & Toxicology, USA; Neuroscience Graduate Program, USA
| | | | - Norelle C Wildburger
- Department of Pharmacology & Toxicology, USA; Neuroscience Graduate Program, USA
| | | | | | | | | | | | - Jai S Rudra
- Department of Pharmacology & Toxicology, USA
| | - Thomas A Green
- Department of Pharmacology & Toxicology, USA; Center for Addiction Research, USA
| | | | - Fernanda Laezza
- Department of Pharmacology & Toxicology, USA; Center for Addiction Research, USA; Center for Biomedical Engineering, USA; Mitchell Center for Neurodegenerative Diseases, USA.
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