1
|
Krogman WL, Woodard T, McKay RSF. Anesthetic Mechanisms: Synergistic Interactions With Lipid Rafts and Voltage-Gated Sodium Channels. Anesth Analg 2024; 139:92-106. [PMID: 37968836 DOI: 10.1213/ane.0000000000006738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
Despite successfully utilizing anesthetics for over 150 years, the mechanism of action remains relatively unknown. Recent studies have shown promising results, but due to the complex interactions between anesthetics and their targets, there remains a clear need for further mechanistic research. We know that lipophilicity is directly connected to anesthetic potency since lipid solubility relates to anesthetic partition into the membrane. However, clinically relevant concentrations of anesthetics do not significantly affect lipid bilayers but continue to influence various molecular targets. Lipid rafts are derived from liquid-ordered phases of the plasma membrane that contain increased concentrations of cholesterol and sphingomyelin and act as staging platforms for membrane proteins, including ion channels. Although anesthetics do not perturb membranes at clinically relevant concentrations, they have recently been shown to target lipid rafts. In this review, we summarize current research on how different types of anesthetics-local, inhalational, and intravenous-bind and affect both lipid rafts and voltage-gated sodium channels, one of their major targets, and how those effects synergize to cause anesthesia and analgesia. Local anesthetics block voltage-gated sodium channel pores while also disrupting lipid packing in ordered membranes. Inhalational anesthetics bind to the channel pore and the voltage-sensing domain while causing an increase in the number, size, and diameter of lipid rafts. Intravenous anesthetics bind to the channel primarily at the voltage-sensing domain and the selectivity filter, while causing lipid raft perturbation. These changes in lipid nanodomain structure possibly give proteins access to substrates that have translocated as a result of these structural alterations, resulting in lipid-driven anesthesia. Overall, anesthetics can impact channel activity either through direct interaction with the channel, indirectly through the lipid raft, or both. Together, these result in decreased sodium ion flux into the cell, disrupting action potentials and producing anesthetic effects. However, more research is needed to elucidate the indirect mechanisms associated with channel disruption through the lipid raft, as not much is known about anionic lipid products and their influence over voltage-gated sodium channels. Anesthetics' effect on S-palmitoylation, a promising mechanism for direct and indirect influence over voltage-gated sodium channels, is another auspicious avenue of research. Understanding the mechanisms of different types of anesthetics will allow anesthesiologists greater flexibility and more specificity when treating patients.
Collapse
Affiliation(s)
- William L Krogman
- From the Department of Anesthesiology, University of Kansas School of Medicine - Wichita, Wichita, Kansas
| | | | | |
Collapse
|
2
|
Ransdell JL, Carrasquillo Y, Bosch MK, Mellor RL, Ornitz DM, Nerbonne JM. Loss of Intracellular Fibroblast Growth Factor 14 (iFGF14) Increases the Excitability of Mature Hippocampal and Cortical Pyramidal Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.04.592532. [PMID: 38746081 PMCID: PMC11092765 DOI: 10.1101/2024.05.04.592532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Mutations in FGF14 , which encodes intracellular fibroblast growth factor 14 (iFGF14), have been linked to spinocerebellar ataxia type 27 (SCA27), a multisystem disorder associated with progressive deficits in motor coordination and cognitive function. Mice ( Fgf14 -/- ) lacking iFGF14 display similar phenotypes, and we have previously shown that the deficits in motor coordination reflect reduced excitability of cerebellar Purkinje neurons, owing to the loss of iFGF14-mediated regulation of the voltage-dependence of inactivation of the fast transient component of the voltage-gated Na + (Nav) current, I NaT . Here, we present the results of experiments designed to test the hypothesis that loss of iFGF14 also attenuates the intrinsic excitability of mature hippocampal and cortical pyramidal neurons. Current-clamp recordings from adult mouse hippocampal CA1 pyramidal neurons in acute in vitro slices, however, revealed that repetitive firing rates were higher in Fgf14 -/- , than in wild type (WT), cells. In addition, the waveforms of individual action potentials were altered in Fgf14 -/- hippocampal CA1 pyramidal neurons, and the loss of iFGF14 reduced the time delay between the initiation of axonal and somal action potentials. Voltage-clamp recordings revealed that the loss of iFGF14 altered the voltage-dependence of activation, but not inactivation, of I NaT in CA1 pyramidal neurons. Similar effects of the loss of iFGF14 on firing properties were evident in current-clamp recordings from layer 5 visual cortical pyramidal neurons. Additional experiments demonstrated that the loss of iFGF14 does not alter the distribution of anti-Nav1.6 or anti-ankyrin G immunofluorescence labeling intensity along the axon initial segments (AIS) of mature hippocampal CA1 or layer 5 visual cortical pyramidal neurons in situ . Taken together, the results demonstrate that, in contrast with results reported for neonatal (rat) hippocampal pyramidal neurons in dissociated cell culture, the loss of iFGF14 does not disrupt AIS architecture or Nav1.6 localization/distribution along the AIS of mature hippocampal (or cortical) pyramidal neurons in situ .
Collapse
|
3
|
Ohori S, Miyauchi A, Osaka H, Lourenco CM, Arakaki N, Sengoku T, Ogata K, Honjo RS, Kim CA, Mitsuhashi S, Frith MC, Seyama R, Tsuchida N, Uchiyama Y, Koshimizu E, Hamanaka K, Misawa K, Miyatake S, Mizuguchi T, Saito K, Fujita A, Matsumoto N. Biallelic structural variations within FGF12 detected by long-read sequencing in epilepsy. Life Sci Alliance 2023; 6:e202302025. [PMID: 37286232 PMCID: PMC10248215 DOI: 10.26508/lsa.202302025] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/22/2023] [Accepted: 05/23/2023] [Indexed: 06/09/2023] Open
Abstract
We discovered biallelic intragenic structural variations (SVs) in FGF12 by applying long-read whole genome sequencing to an exome-negative patient with developmental and epileptic encephalopathy (DEE). We also found another DEE patient carrying a biallelic (homozygous) single-nucleotide variant (SNV) in FGF12 that was detected by exome sequencing. FGF12 heterozygous recurrent missense variants with gain-of-function or heterozygous entire duplication of FGF12 are known causes of epilepsy, but biallelic SNVs/SVs have never been described. FGF12 encodes intracellular proteins interacting with the C-terminal domain of the alpha subunit of voltage-gated sodium channels 1.2, 1.5, and 1.6, promoting excitability by delaying fast inactivation of the channels. To validate the molecular pathomechanisms of these biallelic FGF12 SVs/SNV, highly sensitive gene expression analyses using lymphoblastoid cells from the patient with biallelic SVs, structural considerations, and Drosophila in vivo functional analysis of the SNV were performed, confirming loss-of-function. Our study highlights the importance of small SVs in Mendelian disorders, which may be overlooked by exome sequencing but can be detected efficiently by long-read whole genome sequencing, providing new insights into the pathomechanisms of human diseases.
Collapse
Affiliation(s)
- Sachiko Ohori
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Genetics, Kitasato University Hospital, Sagamihara, Japan
| | - Akihiko Miyauchi
- Department of Pediatrics, Jichi Medical School, Shimotsuke, Japan
| | - Hitoshi Osaka
- Department of Pediatrics, Jichi Medical School, Shimotsuke, Japan
| | - Charles Marques Lourenco
- Neurogenetics Department, Faculdade de Medicina de São José do Rio Preto, São Jose do Rio Preto, Brazil
- Personalized Medicine Department, Special Education Sector at DLE/Grupo Pardini, Belo Horizonte, Brazil
| | - Naohiro Arakaki
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Shizuoka, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Shizuoka, Japan
| | - Toru Sengoku
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kazuhiro Ogata
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Rachel Sayuri Honjo
- Unidade de Genética Médica do Instituto da Criança, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Chong Ae Kim
- Unidade de Genética Médica do Instituto da Criança, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Satomi Mitsuhashi
- Department of Neurology, St. Marianna University School of Medicine, Kawasaki, Japan
| | - Martin C Frith
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
- Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Japan
- Computational Bio Big-Data Open Innovation Laboratory, AIST, Tokyo, Japan
| | - Rie Seyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Obstetrics and Gynecology, Juntendo University, Tokyo, Japan
| | - Naomi Tsuchida
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, Japan
| | - Yuri Uchiyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, Japan
| | - Eriko Koshimizu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kohei Hamanaka
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kazuharu Misawa
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Clinical Genetics, Yokohama City University Hospital, Yokohama, Japan
| | - Takeshi Mizuguchi
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kuniaki Saito
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Shizuoka, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Shizuoka, Japan
| | - Atsushi Fujita
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| |
Collapse
|
4
|
Sun J, Kulandaisamy A, Liu J, Hu K, Gromiha MM, Zhang Y. Machine learning in computational modelling of membrane protein sequences and structures: From methodologies to applications. Comput Struct Biotechnol J 2023; 21:1205-1226. [PMID: 36817959 PMCID: PMC9932300 DOI: 10.1016/j.csbj.2023.01.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/16/2023] [Accepted: 01/25/2023] [Indexed: 01/29/2023] Open
Abstract
Membrane proteins mediate a wide spectrum of biological processes, such as signal transduction and cell communication. Due to the arduous and costly nature inherent to the experimental process, membrane proteins have long been devoid of well-resolved atomic-level tertiary structures and, consequently, the understanding of their functional roles underlying a multitude of life activities has been hampered. Currently, computational tools dedicated to furthering the structure-function understanding are primarily focused on utilizing intelligent algorithms to address a variety of site-wise prediction problems (e.g., topology and interaction sites), but are scattered across different computing sources. Moreover, the recent advent of deep learning techniques has immensely expedited the development of computational tools for membrane protein-related prediction problems. Given the growing number of applications optimized particularly by manifold deep neural networks, we herein provide a review on the current status of computational strategies mainly in membrane protein type classification, topology identification, interaction site detection, and pathogenic effect prediction. Meanwhile, we provide an overview of how the entire prediction process proceeds, including database collection, data pre-processing, feature extraction, and method selection. This review is expected to be useful for developing more extendable computational tools specific to membrane proteins.
Collapse
Affiliation(s)
- Jianfeng Sun
- Botnar Research Centre, Nuffield Department of Orthopedics, Rheumatology, and Musculoskeletal Sciences, University of Oxford, Headington, Oxford OX3 7LD, UK
| | - Arulsamy Kulandaisamy
- Department of Biotechnology, Bhupat and Jyoti Mehta School of BioSciences, Indian Institute of Technology Madras, Chennai 600 036, Tamilnadu, India
| | - Jacklyn Liu
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, UK
| | - Kai Hu
- Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education, Xiangtan University, Xiangtan 411105, China
| | - M. Michael Gromiha
- Department of Biotechnology, Bhupat and Jyoti Mehta School of BioSciences, Indian Institute of Technology Madras, Chennai 600 036, Tamilnadu, India,Corresponding authors.
| | - Yuan Zhang
- Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education, Xiangtan University, Xiangtan 411105, China,Corresponding authors.
| |
Collapse
|
5
|
Shen KF, Yue J, Wu ZF, Wu KF, Zhu G, Yang XL, Wang ZK, Wang J, Liu SY, Yang H, Zhang CQ. Fibroblast growth factor 13 is involved in the pathogenesis of temporal lobe epilepsy. Cereb Cortex 2022; 32:5259-5272. [PMID: 35195262 DOI: 10.1093/cercor/bhac012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/08/2022] [Accepted: 01/09/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Temporal lobe epilepsy (TLE) is the most common drug-resistant epilepsy in adults, with pathological mechanisms remaining to be fully elucidated. Fibroblast Growth Factor 13 (FGF13) encodes an intracellular protein involved in microtubule stabilization and regulation of voltage-gated sodium channels (VGSCs) function. FGF13 mutation has been identified in patients with inherent seizure, suggesting a potential association between FGF13 and the etiology of TLE. Here, we set to explore the pathological role of FGF13 in the etiology of TLE. RESULTS We found that the expression of FGF13 was increased in the cortical lesions and CA1 region of sclerotic hippocampus and correlated with the seizure frequency in TLE patients. Also, Fgf13 expression was increased in the hippocampus of chronic TLE mice generated by kainic acid (KA) injection. Furthermore, Fgf13 knockdown or overexpression was respectively found to attenuate or potentiate the effects of KA on axonal length, somatic area and the VGSCs-mediated current in the hippocampal neurons. CONCLUSIONS Taken together, these findings suggest that FGF13 is involved in the pathogenesis of TLE by modulating microtubule activity and neuronal excitability.
Collapse
Affiliation(s)
- Kai-Feng Shen
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing 400037, China
| | - Jiong Yue
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing 400037, China
| | - Zhi-Feng Wu
- Department of Pedatrics, Xinqiao Hospital, Army Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing 400037, China
| | - Ke-Fu Wu
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing 400037, China
| | - Gang Zhu
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing 400037, China
| | - Xiao-Lin Yang
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing 400037, China
| | - Zhong-Ke Wang
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing 400037, China
| | - Jing Wang
- Department of Pain Management, Henan Provincial People's hospital, 7 Weiwu Road, Jinshui District, Zhengzhou 450008, China.,Zhongshan Medical School, Sun Yat-sen University, 74 Zhongshan Second Road, Yuexiu District, Guangzhou 510080, China
| | - Shi-Yong Liu
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing 400037, China
| | - Hui Yang
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing 400037, China
| | - Chun-Qing Zhang
- Department of Neurosurgery, Xinqiao Hospital, Army Medical University, 183 Xinqiao Main Street, Shapingba District, Chongqing 400037, China
| |
Collapse
|
6
|
Effraim PR, Estacion M, Zhao P, Sosniak D, Waxman SG, Dib-Hajj SD. Fibroblast growth factor homologous factor 2 attenuates excitability of DRG neurons. J Neurophysiol 2022; 128:1258-1266. [PMID: 36222860 PMCID: PMC9909838 DOI: 10.1152/jn.00361.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Fibroblast growth factor homologous factors (FHFs) are cytosolic members of the superfamily of the FGF proteins. Four members of this subfamily (FHF1-4) are differentially expressed in multiple tissues in an isoform-dependent manner. Mutations in FHF proteins have been associated with multiple neurological disorders. FHF proteins bind to the COOH terminus of voltage-gated sodium (Nav) channels and regulate current amplitude and gating properties of these channels. FHF2, which is expressed in dorsal root ganglia (DRG) neurons, has two main splicing isoforms: FHF2A and FHF2B, which differ in the length and sequence of their NH2 termini, have been shown to differentially regulate gating properties of Nav1.7, a channel that is a major driver of DRG neuron firing. FHF2 expression levels are downregulated after peripheral nerve axotomy, which suggests that they may regulate neuronal excitability via an action on Nav channels after injury. We have previously shown that knockdown of FHF2 leads to gain-of-function changes in Nav1.7 gating properties: enhanced repriming, increased current density, and hyperpolarized activation. From this we posited that knockdown of FHF2 might also lead to DRG hyperexcitability. Here we show that knockdown of either FHF2A alone or all isoforms of FHF2 results in increased DRG neuron excitability. In addition, we demonstrate that supplementation of FHF2A and FHF2B reduces DRG neuron excitability. Overexpression of FHF2A or FHF2B also reduced excitability of DRG neurons treated with a cocktail of inflammatory mediators, a model of inflammatory pain. Our data suggest that increased neuronal excitability after nerve injury might be triggered, in part, via a loss of FHF2-Nav1.7 interaction.NEW & NOTEWORTHY FHF2 is known to bind to and modulate the function of Nav1.7. FHF2 expression is also reduced after nerve injury. We demonstrate that knockdown of FHF2 expression increases DRG neuronal excitability. More importantly, overexpression of FHF2 reduces DRG excitability in basal conditions and in the presence of inflammatory mediators (a model of inflammatory pain). These results suggest that FHF2 could potentially be used as a tool to reduce DRG neuronal excitability and to treat pain.
Collapse
Affiliation(s)
- Philip R. Effraim
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06510
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Mark Estacion
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Peng Zhao
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Daniel Sosniak
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Stephen G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Sulayman D. Dib-Hajj
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| |
Collapse
|
7
|
Upchurch CM, Combe CL, Knowlton CJ, Rousseau VG, Gasparini S, Canavier CC. Long-Term Inactivation of Sodium Channels as a Mechanism of Adaptation in CA1 Pyramidal Neurons. J Neurosci 2022; 42:3768-3782. [PMID: 35332085 PMCID: PMC9087813 DOI: 10.1523/jneurosci.1914-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 01/28/2022] [Accepted: 03/09/2022] [Indexed: 11/21/2022] Open
Abstract
Many hippocampal CA1 pyramidal cells function as place cells, increasing their firing rate when a specific place field is traversed. The dependence of CA1 place cell firing on position within the place field is asymmetric. We investigated the source of this asymmetry by injecting triangular depolarizing current ramps to approximate the spatially tuned, temporally diffuse depolarizing synaptic input received by these neurons while traversing a place field. Ramps were applied to CA1 pyramidal neurons from male rats in vitro (slice electrophysiology) and in silico (multicompartmental NEURON model). Under control conditions, CA1 neurons fired more action potentials at higher frequencies on the up-ramp versus the down-ramp. This effect was more pronounced for dendritic compared with somatic ramps. We incorporated a four-state Markov scheme for NaV1.6 channels into our model and calibrated the spatial dependence of long-term inactivation according to the literature; this spatial dependence was sufficient to explain the difference in dendritic versus somatic ramps. Long-term inactivation reduced the firing frequency by decreasing open-state occupancy, and reduced spike amplitude during trains by decreasing occupancy in the closed state, which comprises the available pool. PKC activator phorbol-dibutyrate, known to reduce NaV long-term inactivation, removed spike amplitude attenuation in vitro more visibly in dendrites and greatly reduced adaptation, consistent with our hypothesized mechanism. Intracellular application of a peptide inducing long-term NaV inactivation elicited spike amplitude attenuation during spike trains in the soma and greatly enhanced adaptation. Our synergistic experimental/computational approach shows that long-term inactivation of NaV1.6 is a key mechanism of adaptation in CA1 pyramidal cells.SIGNIFICANCE STATEMENT The hippocampus plays an important role in certain types of memory, in part through context-specific firing of "place cells"; these cells were first identified in rodents as being particularly active when an animal is in a specific location in an environment, called the place field of that neuron. In this in vitro/in silico study, we found that long-term inactivation of sodium channels causes adaptation in the firing rate that could potentially skew the firing of CA1 hippocampal pyramidal neurons earlier within a place field. A computational model of the sodium channel revealed differential regulation of spike frequency and amplitude by long-term inactivation, which may be a general mechanism for spike frequency adaptation in the CNS.
Collapse
Affiliation(s)
- Carol M Upchurch
- Department of Cell Biology & Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Crescent L Combe
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Christopher J Knowlton
- Department of Cell Biology & Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Valery G Rousseau
- Department of Cell Biology & Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Sonia Gasparini
- Department of Cell Biology & Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Carmen C Canavier
- Department of Cell Biology & Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| |
Collapse
|
8
|
Lindner JS, Rajayer SR, Martiszus BJ, Smith SM. Cinacalcet inhibition of neuronal action potentials preferentially targets the fast inactivated state of voltage-gated sodium channels. Front Physiol 2022; 13:1066467. [PMID: 36601343 PMCID: PMC9806421 DOI: 10.3389/fphys.2022.1066467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
Abstract
Voltage-gated sodium channel (VGSC) activation is essential for action potential generation in the brain. Allosteric calcium-sensing receptor (CaSR) agonist, cinacalcet, strongly and ubiquitously inhibits VGSC currents in neocortical neurons via an unidentified, G-protein-dependent inhibitory molecule. Here, using whole-cell patch VGSC clamp methods, we investigated the voltage-dependence of cinacalcet-mediated inhibition of VGSCs and the channel state preference of cinacalcet. The rate of inhibition of VGSC currents was accelerated at more depolarized holding potentials. Cinacalcet shifted the voltage-dependence of both fast and slow inactivation of VGSC currents in the hyperpolarizing direction. Utilizing a simple model, the voltage-dependence of VGSC current inhibition may be explained if the affinity of the inhibitory molecule to the channel states follows the sequence: fast-inactivated > slow-inactivated > resting. The state dependence of VGSC current inhibition contributes to the non-linearity of action potential block by cinacalcet. This dynamic and abundant signaling pathway by which cinacalcet regulates VGSC currents provides an important voltage-dependent mechanism for modulating central neuronal excitability.
Collapse
Affiliation(s)
- Jamie S Lindner
- Section of Pulmonary and Critical Care Medicine, VA Portland Health Care System, Portland, OR, United States.,Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Oregon Health & Science University, Portland, OR, United States
| | - Salil R Rajayer
- Section of Pulmonary and Critical Care Medicine, VA Portland Health Care System, Portland, OR, United States.,Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Oregon Health & Science University, Portland, OR, United States
| | - Briana J Martiszus
- Section of Pulmonary and Critical Care Medicine, VA Portland Health Care System, Portland, OR, United States.,Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Oregon Health & Science University, Portland, OR, United States
| | - Stephen M Smith
- Section of Pulmonary and Critical Care Medicine, VA Portland Health Care System, Portland, OR, United States.,Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Oregon Health & Science University, Portland, OR, United States
| |
Collapse
|
9
|
Arribas-Blázquez M, Piniella D, Olivos-Oré LA, Bartolomé-Martín D, Leite C, Giménez C, Artalejo AR, Zafra F. Regulation of the voltage-dependent sodium channel Na V1.1 by AKT1. Neuropharmacology 2021; 197:108745. [PMID: 34375627 DOI: 10.1016/j.neuropharm.2021.108745] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 07/09/2021] [Accepted: 08/02/2021] [Indexed: 11/28/2022]
Abstract
The voltage-sensitive sodium channel NaV1.1 plays a critical role in regulating excitability of GABAergic neurons and mutations in the corresponding gene are associated to Dravet syndrome and other forms of epilepsy. The activity of this channel is regulated by several protein kinases. To identify novel regulatory kinases we screened a library of activated kinases and we found that AKT1 was able to directly phosphorylate NaV1.1. In vitro kinase assays revealed that the phosphorylation site was located in the C-terminal part of the large intracellular loop connecting domains I and II of NaV1.1, a region that is known to be targeted by other kinases like PKA and PKC. Electrophysiological recordings revealed that activated AKT1 strongly reduced peak Na+ currents and displaced the inactivation curve to more negative potentials in HEK-293 cell stably expressing NaV1.1. These alterations in current amplitude and steady-state inactivation were mimicked by SC79, a specific activator of AKT1, and largely reverted by triciribine, a selective inhibitor. Neurons expressing endogenous NaV1.1 in primary cultures were identified by expressing a fluorescent protein under the NaV1.1 promoter. There, we also observed a strong decrease in the current amplitude after addition of SC79, but small effects on the inactivation parameters. Altogether, we propose a novel mechanism that might regulate the excitability of neural networks in response to AKT1, a kinase that plays a pivotal role under physiological and pathological conditions, including epileptogenesis.
Collapse
Affiliation(s)
- Marina Arribas-Blázquez
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; Department of Pharmacology and Toxicology, Veterinary Faculty, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Dolores Piniella
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; IdiPAZ, Instituto de Salud Carlos III, Madrid, Spain
| | - Luis A Olivos-Oré
- Department of Pharmacology and Toxicology, Veterinary Faculty, Universidad Complutense de Madrid, 28040, Madrid, Spain; Instituto Universitario de Investigación en Neuroquímica, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - David Bartolomé-Martín
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; IdiPAZ, Instituto de Salud Carlos III, Madrid, Spain
| | - Cristiana Leite
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Cecilio Giménez
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; IdiPAZ, Instituto de Salud Carlos III, Madrid, Spain
| | - Antonio R Artalejo
- Department of Pharmacology and Toxicology, Veterinary Faculty, Universidad Complutense de Madrid, 28040, Madrid, Spain; Instituto Universitario de Investigación en Neuroquímica, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Francisco Zafra
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; IdiPAZ, Instituto de Salud Carlos III, Madrid, Spain.
| |
Collapse
|
10
|
Ohtubo Y. Slow recovery from the inactivation of voltage-gated sodium channel Nav1.3 in mouse taste receptor cells. Pflugers Arch 2021; 473:953-968. [PMID: 33881614 DOI: 10.1007/s00424-021-02563-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/02/2021] [Accepted: 04/04/2021] [Indexed: 02/06/2023]
Abstract
Action potentials play an important role in neurotransmitter release in response to taste. Here, I have investigated voltage-gated Na+ channels, a primary component of action potentials, in respective cell types of mouse fungiform taste bud cells (TBCs) with in situ whole-cell clamping and single-cell RT-PCR techniques. The cell types of TBCs electrophysiologically examined were determined immunohistochemically using the type III inositol 1,4,5-triphoshate receptor as a type II cell marker and synaptosomal-associated protein 25 as a type III cell marker. I show that type II cells, type III cells, and TBCs not immunoreactive to these markers (likely type I cells) generate voltage-gated Na+ currents. The recovery following inactivation of these currents was well fitted with double exponential curves. The time constants in type III cells (~20 ms and ~ 1 s) were significantly slower than respective time constants in other cell types. RT-PCR analysis indicated the expression of Nav1.3, Nav1.5, Nav1.6, and β1 subunit mRNAs in TBCs. Pharmacological inhibition and single-cell RT-PCR studies demonstrated that type II and type III cells principally express tetrodotoxin (TTX)-sensitive Nav1.3 channels and that ~ 30% of type I cells express TTX-resistant Nav1.5 channels. The auxiliary β1 subunit that modulates gating kinetics was rarely detected in TBCs. As the β1 subunit co-expressed with an α subunit is known to accelerate the recovery from inactivation, it is likely that voltage-gated Na+ channels in TBCs may function without β subunits. Slow recovery from inactivation, especially in type III cells, may limit high-frequency firing in response to taste substances.
Collapse
Affiliation(s)
- Yoshitaka Ohtubo
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Hibikino 2-4, Kitakyushu, 808-0196, Japan.
| |
Collapse
|
11
|
Carbone E. Fast inactivation of Nav1.3 channels by FGF14 proteins: An unconventional way to regulate the slow firing of adrenal chromaffin cells. J Gen Physiol 2021; 153:211934. [PMID: 33792614 PMCID: PMC8020463 DOI: 10.1085/jgp.202112879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Using Nav1.3 and FGF14 KO mice, Martinez-Espinosa et al. provide new findings on how intracellular FGF14 proteins interfere with the endogenous fast inactivation gating and regulate the “long-term inactivation” of Nav1.3 channels that sets Nav channel availability and spike adaptation during sustained stimulation in adrenal chromaffin cells.
Collapse
Affiliation(s)
- Emilio Carbone
- Department of Drug Science, Lab of Cell Physiology and Molecular Neuroscience, University of Torino, Torino, Italy
| |
Collapse
|
12
|
Martinez-Espinosa PL, Yang C, Xia XM, Lingle CJ. Nav1.3 and FGF14 are primary determinants of the TTX-sensitive sodium current in mouse adrenal chromaffin cells. J Gen Physiol 2021; 153:211839. [PMID: 33651884 PMCID: PMC8020717 DOI: 10.1085/jgp.202012785] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 01/07/2021] [Accepted: 01/19/2021] [Indexed: 12/29/2022] Open
Abstract
Adrenal chromaffin cells (CCs) in rodents express rapidly inactivating, tetrodotoxin (TTX)-sensitive sodium channels. The resulting current has generally been attributed to Nav1.7, although a possible role for Nav1.3 has also been suggested. Nav channels in rat CCs rapidly inactivate via two independent pathways which differ in their time course of recovery. One subpopulation recovers with time constants similar to traditional fast inactivation and the other ∼10-fold slower, but both pathways can act within a single homogenous population of channels. Here, we use Nav1.3 KO mice to probe the properties and molecular components of Nav current in CCs. We find that the absence of Nav1.3 abolishes all Nav current in about half of CCs examined, while a small, fast inactivating Nav current is still observed in the rest. To probe possible molecular components underlying slow recovery from inactivation, we used mice null for fibroblast growth factor homology factor 14 (FGF14). In these cells, the slow component of recovery from fast inactivation is completely absent in most CCs, with no change in the time constant of fast recovery. The use dependence of Nav current reduction during trains of stimuli in WT cells is completely abolished in FGF14 KO mice, directly demonstrating a role for slow recovery from inactivation in determining Nav current availability. Our results indicate that FGF14-mediated inactivation is the major determinant defining use-dependent changes in Nav availability in CCs. These results establish that Nav1.3, like other Nav isoforms, can also partner with FGF subunits, strongly regulating Nav channel function.
Collapse
Affiliation(s)
| | - Chengtao Yang
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO
| | - Xiao-Ming Xia
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO
| | - Christopher J Lingle
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO
| |
Collapse
|
13
|
Martinez-Espinosa PL, Neely A, Ding J, Lingle CJ. Fast inactivation of Nav current in rat adrenal chromaffin cells involves two independent inactivation pathways. J Gen Physiol 2021; 153:211834. [PMID: 33647101 PMCID: PMC7927663 DOI: 10.1085/jgp.202012784] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 01/07/2021] [Accepted: 01/19/2021] [Indexed: 12/13/2022] Open
Abstract
Voltage-dependent sodium (Nav) current in adrenal chromaffin cells (CCs) is rapidly inactivating and tetrodotoxin (TTX)–sensitive. The fractional availability of CC Nav current has been implicated in regulation of action potential (AP) frequency and the occurrence of slow-wave burst firing. Here, through recordings of Nav current in rat CCs, primarily in adrenal medullary slices, we describe unique inactivation properties of CC Nav inactivation that help define AP firing rates in CCs. The key feature of CC Nav current is that recovery from inactivation, even following brief (5 ms) inactivation steps, exhibits two exponential components of similar amplitude. Various paired pulse protocols show that entry into the fast and slower recovery processes result from largely independent competing inactivation pathways, each of which occurs with similar onset times at depolarizing potentials. Over voltages from −120 to −80 mV, faster recovery varies from ∼3 to 30 ms, while slower recovery varies from ∼50 to 400 ms. With strong depolarization (above −10 mV), the relative entry into slow or fast recovery pathways is similar and independent of voltage. Trains of short depolarizations favor recovery from fast recovery pathways and result in cumulative increases in the slow recovery fraction. Dual-pathway fast inactivation, by promoting use-dependent accumulation in slow recovery pathways, dynamically regulates Nav availability. Consistent with this finding, repetitive AP clamp waveforms at 1–10 Hz frequencies reduce Nav availability 80–90%, depending on holding potential. These results indicate that there are two distinct pathways of fast inactivation, one leading to conventional fast recovery and the other to slower recovery, which together are well-suited to mediate use-dependent changes in Nav availability.
Collapse
Affiliation(s)
| | - Alan Neely
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO
| | - Jiuping Ding
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO
| | - Christopher J Lingle
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO
| |
Collapse
|
14
|
Kleber AG, Wit AL. The Interaction Between Na + and Ca 2+ Inward Currents in Cardiac Propagation. Circ Res 2020; 127:1549-1551. [PMID: 33270548 DOI: 10.1161/circresaha.120.318316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Andre G Kleber
- Department of Pathology, Harvard Medical School, Boston, MA (A.G.K.)
| | - Andrew L Wit
- Department of Pathology, Harvard Medical School, Boston, MA (A.G.K.)
| |
Collapse
|
15
|
Kim MJ, Yum MS, Seo GH, Lee Y, Jang HN, Ko TS, Lee BH. Clinical Application of Whole Exome Sequencing to Identify Rare but Remediable Neurologic Disorders. J Clin Med 2020; 9:jcm9113724. [PMID: 33233562 PMCID: PMC7699758 DOI: 10.3390/jcm9113724] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/17/2022] Open
Abstract
Background: The aim of this study was to describe the application of whole exome sequencing (WES) in the accurate genetic diagnosis and personalized treatment of extremely rare neurogenetic disorders. Methods: From 2017 to 2019, children with neurodevelopmental symptoms were evaluated using WES in the pediatric neurology clinic and medical genetics center. The clinical presentation, laboratory findings including the genetic results from WES, and diagnosis-based treatment and outcomes of the four patients are discussed. Results: A total of 376 children with neurodevelopmental symptom were evaluated by WES, and four patients (1.1%) were diagnosed with treatable neurologic disorders. Patient 1 (Pt 1) showed global muscle hypotonia, dysmorphic facial features, and multiple anomalies beginning in the perinatal period. Pt 1 was diagnosed with congenital myasthenic syndrome 22 of PREPL deficiency. Pt 2 presented with hypotonia and developmental arrest and was diagnosed with autosomal recessive dopa-responsive dystonia due to TH deficiency. Pt 3, who suffered from intractable epilepsy and progressive cognitive decline, was diagnosed with epileptic encephalopathy 47 with a heterozygous FGF12 mutation. Pt 4 presented with motor delay and episodic ataxia and was diagnosed with episodic ataxia type II (heterozygous CACNA1A mutation). The patients’ major neurologic symptoms were remarkably relieved with pyridostigmine (Pt 1), levodopa (Pt 2), sodium channel blocker (Pt 3), and acetazolamide (Pt 4), and most patients regained developmental milestones in the follow-up period (0.4 to 3 years). Conclusions: The early application of WES helps in the identification of extremely rare genetic diseases, for which effective treatment modalities exist. Ultimately, WES resulted in optimal clinical outcomes of affected patients.
Collapse
Affiliation(s)
- Min-Jee Kim
- Department of Pediatrics, Asan Medical Center Children’s Hospital, Ulsan University College of Medicine 88, Olympic-ro 43-Gil, Songpa-Gu, Seoul 05505, Korea; (M.-J.K.); (H.N.J.); (T.-S.K.)
| | - Mi-Sun Yum
- Department of Pediatrics, Asan Medical Center Children’s Hospital, Ulsan University College of Medicine 88, Olympic-ro 43-Gil, Songpa-Gu, Seoul 05505, Korea; (M.-J.K.); (H.N.J.); (T.-S.K.)
- Correspondence: ; Tel.: +82-2-3010-3386; Fax: +82-2-3010-3356
| | - Go Hun Seo
- 3billion Inc., Seoul 06193, Korea; (G.H.S.); (B.H.L.)
| | - Yena Lee
- Department of Genetics, Asan Medical Center, Ulsan University College of Medicine, 88, Olympic-ro 43-Gil, Songpa-Gu, Seoul 05505, Korea;
| | - Han Na Jang
- Department of Pediatrics, Asan Medical Center Children’s Hospital, Ulsan University College of Medicine 88, Olympic-ro 43-Gil, Songpa-Gu, Seoul 05505, Korea; (M.-J.K.); (H.N.J.); (T.-S.K.)
| | - Tae-Sung Ko
- Department of Pediatrics, Asan Medical Center Children’s Hospital, Ulsan University College of Medicine 88, Olympic-ro 43-Gil, Songpa-Gu, Seoul 05505, Korea; (M.-J.K.); (H.N.J.); (T.-S.K.)
| | - Beom Hee Lee
- 3billion Inc., Seoul 06193, Korea; (G.H.S.); (B.H.L.)
| |
Collapse
|
16
|
Park DS, Shekhar A, Santucci J, Redel-Traub G, Solinas S, Mintz S, Lin X, Chang EW, Narke D, Xia Y, Goldfarb M, Fishman GI. Ionic Mechanisms of Impulse Propagation Failure in the FHF2-Deficient Heart. Circ Res 2020; 127:1536-1548. [PMID: 32962518 DOI: 10.1161/circresaha.120.317349] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE FHFs (fibroblast growth factor homologous factors) are key regulators of sodium channel (NaV) inactivation. Mutations in these critical proteins have been implicated in human diseases including Brugada syndrome, idiopathic ventricular arrhythmias, and epileptic encephalopathy. The underlying ionic mechanisms by which reduced Nav availability in Fhf2 knockout (Fhf2KO) mice predisposes to abnormal excitability at the tissue level are not well defined. OBJECTIVE Using animal models and theoretical multicellular linear strands, we examined how FHF2 orchestrates the interdependency of sodium, calcium, and gap junctional conductances to safeguard cardiac conduction. METHODS AND RESULTS Fhf2KO mice were challenged by reducing calcium conductance (gCaV) using verapamil or by reducing gap junctional conductance (Gj) using carbenoxolone or by backcrossing into a cardiomyocyte-specific Cx43 (connexin 43) heterozygous background. All conditions produced conduction block in Fhf2KO mice, with Fhf2 wild-type (Fhf2WT) mice showing normal impulse propagation. To explore the ionic mechanisms of block in Fhf2KO hearts, multicellular linear strand models incorporating FHF2-deficient Nav inactivation properties were constructed and faithfully recapitulated conduction abnormalities seen in mutant hearts. The mechanisms of conduction block in mutant strands with reduced gCaV or diminished Gj are very different. Enhanced Nav inactivation due to FHF2 deficiency shifts dependence onto calcium current (ICa) to sustain electrotonic driving force, axial current flow, and action potential (AP) generation from cell-to-cell. In the setting of diminished Gj, slower charging time from upstream cells conspires with accelerated Nav inactivation in mutant strands to prevent sufficient downstream cell charging for AP propagation. CONCLUSIONS FHF2-dependent effects on Nav inactivation ensure adequate sodium current (INa) reserve to safeguard against numerous threats to reliable cardiac impulse propagation.
Collapse
Affiliation(s)
- David S Park
- The Leon H. Charney Division of Cardiology (D.S.P., A.S., J.S., G.R.-T., S.M., X.L., E.W.C., D.N., G.I.F.), New York University School of Medicine
| | - Akshay Shekhar
- The Leon H. Charney Division of Cardiology (D.S.P., A.S., J.S., G.R.-T., S.M., X.L., E.W.C., D.N., G.I.F.), New York University School of Medicine.,Regeneron Pharmaceuticals, Tarrytown, NY (A.S.)
| | - John Santucci
- The Leon H. Charney Division of Cardiology (D.S.P., A.S., J.S., G.R.-T., S.M., X.L., E.W.C., D.N., G.I.F.), New York University School of Medicine
| | - Gabriel Redel-Traub
- The Leon H. Charney Division of Cardiology (D.S.P., A.S., J.S., G.R.-T., S.M., X.L., E.W.C., D.N., G.I.F.), New York University School of Medicine
| | - Sergio Solinas
- University of Zurich, Institute of Neuroinformatics, Switzerland (S.S.).,Hunter College of City University, Department of Biological Sciences, New York (S.S., M.G.)
| | - Shana Mintz
- The Leon H. Charney Division of Cardiology (D.S.P., A.S., J.S., G.R.-T., S.M., X.L., E.W.C., D.N., G.I.F.), New York University School of Medicine
| | - Xianming Lin
- The Leon H. Charney Division of Cardiology (D.S.P., A.S., J.S., G.R.-T., S.M., X.L., E.W.C., D.N., G.I.F.), New York University School of Medicine
| | - Ernest Whanwook Chang
- The Leon H. Charney Division of Cardiology (D.S.P., A.S., J.S., G.R.-T., S.M., X.L., E.W.C., D.N., G.I.F.), New York University School of Medicine
| | - Deven Narke
- The Leon H. Charney Division of Cardiology (D.S.P., A.S., J.S., G.R.-T., S.M., X.L., E.W.C., D.N., G.I.F.), New York University School of Medicine
| | - Yuhe Xia
- Department of Population Health (Y.X.), New York University School of Medicine
| | - Mitchell Goldfarb
- Hunter College of City University, Department of Biological Sciences, New York (S.S., M.G.)
| | - Glenn I Fishman
- The Leon H. Charney Division of Cardiology (D.S.P., A.S., J.S., G.R.-T., S.M., X.L., E.W.C., D.N., G.I.F.), New York University School of Medicine
| |
Collapse
|
17
|
Heyne HO, Baez-Nieto D, Iqbal S, Palmer DS, Brunklaus A, May P, Johannesen KM, Lauxmann S, Lemke JR, Møller RS, Pérez-Palma E, Scholl UI, Syrbe S, Lerche H, Lal D, Campbell AJ, Wang HR, Pan J, Daly MJ. Predicting functional effects of missense variants in voltage-gated sodium and calcium channels. Sci Transl Med 2020; 12:eaay6848. [PMID: 32801145 DOI: 10.1126/scitranslmed.aay6848] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 11/20/2019] [Accepted: 07/22/2020] [Indexed: 12/30/2022]
Abstract
Malfunctions of voltage-gated sodium and calcium channels (encoded by SCNxA and CACNA1x family genes, respectively) have been associated with severe neurologic, psychiatric, cardiac, and other diseases. Altered channel activity is frequently grouped into gain or loss of ion channel function (GOF or LOF, respectively) that often corresponds not only to clinical disease manifestations but also to differences in drug response. Experimental studies of channel function are therefore important, but laborious and usually focus only on a few variants at a time. On the basis of known gene-disease mechanisms of 19 different diseases, we inferred LOF (n = 518) and GOF (n = 309) likely pathogenic variants from the disease phenotypes of variant carriers. By training a machine learning model on sequence- and structure-based features, we predicted LOF or GOF effects [area under the receiver operating characteristics curve (ROC) = 0.85] of likely pathogenic missense variants. Our LOF versus GOF prediction corresponded to molecular LOF versus GOF effects for 87 functionally tested variants in SCN1/2/8A and CACNA1I (ROC = 0.73) and was validated in exome-wide data from 21,703 cases and 128,957 controls. We showed respective regional clustering of inferred LOF and GOF nucleotide variants across the alignment of the entire gene family, suggesting shared pathomechanisms in the SCNxA/CACNA1x family genes.
Collapse
Affiliation(s)
- Henrike O Heyne
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, 5WR36M Helsinki, Finland
| | - David Baez-Nieto
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Sumaiya Iqbal
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Center for Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Duncan S Palmer
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Andreas Brunklaus
- Paediatric Neurosciences Research Group, Royal Hospital for Sick Children, Glasgow G51 4TF, UK
- School of Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Patrick May
- Luxembourg Centre for Systems Biomedicine, Belvaux, University of Luxembourg, 4365 Esch-sur-Alzette, Luxembourg
| | - Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, 4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, 5230 Odense, Denmark
| | - Stephan Lauxmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, 4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, 5230 Odense, Denmark
| | - Eduardo Pérez-Palma
- Cologne Center for Genomics (CCG), University of Cologne, 50923, Germany
- Genomic Medicine Institute, Lemer Research Institute Cleveland Clinic, OH G92J47, USA
| | - Ute I Scholl
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nephrology and Medical Intensive Care and BIH Center for Regenerative Therapies, 10178 Berlin, Germany
- Berlin Institute of Health (BIH), 10178 Berlin, Germany
| | - Steffen Syrbe
- Division of Pediatric Epileptology, Center for Paediatrics and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Dennis Lal
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Cologne Center for Genomics (CCG), University of Cologne, 50923, Germany
- Genomic Medicine Institute, Lemer Research Institute Cleveland Clinic, OH G92J47, USA
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH G92J47, USA
| | - Arthur J Campbell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Center for Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Hao-Ran Wang
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jen Pan
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Mark J Daly
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, 5WR36M Helsinki, Finland
| |
Collapse
|
18
|
Sochacka M, Opalinski L, Szymczyk J, Zimoch MB, Czyrek A, Krowarsch D, Otlewski J, Zakrzewska M. FHF1 is a bona fide fibroblast growth factor that activates cellular signaling in FGFR-dependent manner. Cell Commun Signal 2020; 18:69. [PMID: 32357892 PMCID: PMC7193404 DOI: 10.1186/s12964-020-00573-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 04/01/2020] [Indexed: 12/22/2022] Open
Abstract
Abstract Fibroblast growth factors (FGFs) via their receptors (FGFRs) transduce signals from the extracellular space to the cell interior, modulating pivotal cellular processes such as cell proliferation, motility, metabolism and death. FGF superfamily includes a group of fibroblast growth factor homologous factors (FHFs), proteins whose function is still largely unknown. Since FHFs lack the signal sequence for secretion and are unable to induce FGFR-dependent cell proliferation, these proteins were considered as intracellular proteins that are not involved in signal transduction via FGFRs. Here we demonstrate for the first time that FHF1 directly interacts with all four major FGFRs. FHF1 binding causes efficient FGFR activation and initiation of receptor-dependent signaling cascades. However, the biological effect of FHF1 differs from the one elicited by canonical FGFs, as extracellular FHF1 protects cells from apoptosis, but is unable to stimulate cell division. Our data define FHF1 as a FGFR ligand, emphasizing much greater similarity between FHFs and canonical FGFs than previously indicated. Video Abstract. (MP4 38460 kb)
Graphical abstract ![]()
Collapse
Affiliation(s)
- Martyna Sochacka
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Lukasz Opalinski
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Jakub Szymczyk
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Marta B Zimoch
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Aleksandra Czyrek
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Daniel Krowarsch
- Department of Protein Biotechnology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Jacek Otlewski
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Malgorzata Zakrzewska
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland.
| |
Collapse
|
19
|
Navarro MA, Salari A, Lin JL, Cowan LM, Penington NJ, Milescu M, Milescu LS. Sodium channels implement a molecular leaky integrator that detects action potentials and regulates neuronal firing. eLife 2020; 9:54940. [PMID: 32101161 PMCID: PMC7043890 DOI: 10.7554/elife.54940] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 02/13/2020] [Indexed: 12/18/2022] Open
Abstract
Voltage-gated sodium channels play a critical role in cellular excitability, amplifying small membrane depolarizations into action potentials. Interactions with auxiliary subunits and other factors modify the intrinsic kinetic mechanism to result in new molecular and cellular functionality. We show here that sodium channels can implement a molecular leaky integrator, where the input signal is the membrane potential and the output is the occupancy of a long-term inactivated state. Through this mechanism, sodium channels effectively measure the frequency of action potentials and convert it into Na+ current availability. In turn, the Na+ current can control neuronal firing frequency in a negative feedback loop. Consequently, neurons become less sensitive to changes in excitatory input and maintain a lower firing rate. We present these ideas in the context of rat serotonergic raphe neurons, which fire spontaneously at low frequency and provide critical neuromodulation to many autonomous and cognitive brain functions.
Collapse
Affiliation(s)
- Marco A Navarro
- Division of Biological Sciences, University of Missouri, Columbia, United States
| | - Autoosa Salari
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Jenna L Lin
- Division of Biological Sciences, University of Missouri, Columbia, United States
| | - Luke M Cowan
- Division of Biological Sciences, University of Missouri, Columbia, United States
| | - Nicholas J Penington
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, United States
| | - Mirela Milescu
- Division of Biological Sciences, University of Missouri, Columbia, United States
| | - Lorin S Milescu
- Division of Biological Sciences, University of Missouri, Columbia, United States.,Department of Biology, University of Maryland, College Park, United States
| |
Collapse
|
20
|
Johnstone CN, Pattison AD, Harrison PF, Powell DR, Lock P, Ernst M, Anderson RL, Beilharz TH. FGF13 promotes metastasis of triple-negative breast cancer. Int J Cancer 2020; 147:230-243. [PMID: 31957002 DOI: 10.1002/ijc.32874] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 12/01/2019] [Accepted: 12/09/2019] [Indexed: 12/13/2022]
Abstract
Triple-negative breast cancer (TNBC) represents 10-20% of all human ductal adenocarcinomas and has a poor prognosis relative to other subtypes, due to the high propensity to develop distant metastases. Hence, new molecular targets for therapeutic intervention are needed for TNBC. We recently conducted a rigorous phenotypic and genomic characterization of four isogenic populations of MDA-MB-231 human triple-negative breast cancer cells that possess a range of intrinsic spontaneous metastatic capacities in vivo, ranging from nonmetastatic (MDA-MB-231_ATCC) to highly metastatic to lung, liver, spleen and spine (MDA-MB-231_HM). Gene expression profiling of primary tumours by RNA-Seq identified the fibroblast growth factor homologous factor, FGF13, as highly upregulated in aggressively metastatic MDA-MB-231_HM tumours. Clinically, higher FGF13 mRNA expression was associated with significantly worse relapse free survival in both luminal A and basal-like human breast cancers but was not associated with other clinical variables and was not upregulated in primary tumours relative to normal mammary gland. Stable FGF13 depletion restricted in vitro colony forming ability in MDA-MB-231_HM TNBC cells but not in oestrogen receptor (ER)-positive MCF-7 or MDA-MB-361 cells. However, despite augmenting MDA-MB-231_HM cell migration and invasion in vitro, FGF13 suppression almost completely blocked the spontaneous metastasis of MDA-MB-231_HM orthotopic xenografts to both lung and liver while having negligible impact on primary tumour growth. Together, these data indicate that FGF13 may represent a therapeutic target for blocking metastatic outgrowth of certain TNBCs. Further evaluation of the roles of individual FGF13 protein isoforms in progression of the different subtypes of breast cancer is warranted.
Collapse
Affiliation(s)
- Cameron N Johnstone
- Cancer Research Division, Peter MacCallum Cancer Centre, Victorian Comprehensive Cancer Centre, Parkville, VIC, Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, VIC, Australia.,Department of Clinical Pathology, University of Melbourne, Parkville, VIC, Australia.,Olivia Newton-John Cancer Research Institute, Heidelberg, VIC, Australia.,School of Cancer Medicine, La Trobe University, Bundoora, VIC, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Andrew D Pattison
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia.,Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Paul F Harrison
- Monash Bioinformatics Platform, Monash University, Clayton, VIC, Australia
| | - David R Powell
- Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Monash Bioinformatics Platform, Monash University, Clayton, VIC, Australia
| | - Peter Lock
- LIMS Bioimaging Facility, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, Australia
| | - Matthias Ernst
- Olivia Newton-John Cancer Research Institute, Heidelberg, VIC, Australia.,School of Cancer Medicine, La Trobe University, Bundoora, VIC, Australia
| | - Robin L Anderson
- Cancer Research Division, Peter MacCallum Cancer Centre, Victorian Comprehensive Cancer Centre, Parkville, VIC, Australia.,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, VIC, Australia.,Department of Clinical Pathology, University of Melbourne, Parkville, VIC, Australia.,Olivia Newton-John Cancer Research Institute, Heidelberg, VIC, Australia.,School of Cancer Medicine, La Trobe University, Bundoora, VIC, Australia
| | - Traude H Beilharz
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia.,Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Monash Bioinformatics Platform, Monash University, Clayton, VIC, Australia
| |
Collapse
|
21
|
Li Q, Zhai Z, Li J. Fibroblast growth factor homologous factors are potential ion channel modifiers associated with cardiac arrhythmias. Eur J Pharmacol 2020; 871:172920. [PMID: 31935396 DOI: 10.1016/j.ejphar.2020.172920] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 12/10/2019] [Accepted: 01/10/2020] [Indexed: 12/27/2022]
Abstract
Stable electrical activity in cardiac myocytes is the basis of maintaining normal myocardial systolic and diastolic function. Cardiac ionic currents and their associated regulatory proteins are crucial to myocyte excitability and heart function. Fibroblast growth factor homologous factors (FHFs) are intracellular noncanonical fibroblast growth factors (FGFs) that are incapable of activating FGF receptors. The main functions of FHFs are to regulate ion channels and influence excitability, which are processes involved in sustaining normal cardiac function. In addition to their regulatory effect on ion channels, FHFs can be regulators of cardiac hypertrophic signaling and alter signaling pathways, including the protein kinase, NF<kappa>B, and p53 pathways, which are related to the pathological processes of heart diseases. This review emphasizes FHF-mediated regulation of cardiac excitability and the association of FHFs with cardiac arrhythmias and explores the idea that abnormal FHFs may be an unrecognized cause of cardiac disorders.
Collapse
Affiliation(s)
- Qing Li
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Zhenyu Zhai
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Juxiang Li
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
| |
Collapse
|
22
|
Entire FGF12 duplication by complex chromosomal rearrangements associated with West syndrome. J Hum Genet 2019; 64:1005-1014. [PMID: 31311986 DOI: 10.1038/s10038-019-0641-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/23/2019] [Accepted: 06/26/2019] [Indexed: 11/09/2022]
Abstract
Complex rearrangements of chromosomes 3 and 9 were found in a patient presenting with severe epilepsy, developmental delay, dysmorphic facial features, and skeletal abnormalities. Molecular cytogenetic analysis revealed 46,XX.ish der(9)(3qter→3q28::9p21.1→9p22.3::9p22.3→9qter)(RP11-368G14+,RP11-299O8-,RP11-905L2++,RP11-775E6++). Her dysmorphic features are consistent with 3q29 microduplication syndrome and inv dup del(9p). Trio-based WES of the patient revealed no pathogenic single nucleotide variants causing epilepsy, but confirmed a 3q28q29 duplication involving FGF12, which encodes fibroblast growth factor 12. FGF12 positively regulates the activity of voltage-gated sodium channels. Recently, only one recurrent gain-of-function variant [NM_021032.4:c.341G>A:p.(Arg114His)] in FGF12 was found in a total of 10 patients with severe early-onset epilepsy. We propose that the patient's entire FGF12 duplication may be analogous to the gain-of-function variant in FGF12 in the epileptic phenotype of this patient.
Collapse
|
23
|
Ni H, Rajamani S, Giles WR. Novel regulation of the mammalian cardiac Na + channel by dipeptidyl peptidase 10 interactions: An editorial comment. Int J Cardiol 2019; 284:74-76. [PMID: 30827732 DOI: 10.1016/j.ijcard.2019.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 02/07/2019] [Indexed: 11/29/2022]
Affiliation(s)
- H Ni
- Department of Pharmacology, University of California, Davis, CA, United States of America
| | - S Rajamani
- Cardiometabolic Disorders, Amgen Research, South San Francisco, CA, United States of America
| | - W R Giles
- Faculties of Medicine and Kinesiology, University of Calgary, Calgary, Canada.
| |
Collapse
|
24
|
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.
Collapse
|
25
|
Ransdell JL, Nerbonne JM. Voltage-gated sodium currents in cerebellar Purkinje neurons: functional and molecular diversity. Cell Mol Life Sci 2018; 75:3495-3505. [PMID: 29982847 PMCID: PMC6123253 DOI: 10.1007/s00018-018-2868-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 06/28/2018] [Accepted: 07/03/2018] [Indexed: 01/09/2023]
Abstract
Purkinje neurons, the sole output of the cerebellar cortex, deliver GABA-mediated inhibition to the deep cerebellar nuclei. To subserve this critical function, Purkinje neurons fire repetitively, and at high frequencies, features that have been linked to the unique properties of the voltage-gated sodium (Nav) channels expressed. In addition to the rapidly activating and inactivating, or transient, component of the Nav current (INaT) present in many types of central and peripheral neurons, Purkinje neurons, also expresses persistent (INaP) and resurgent (INaR) Nav currents. Considerable progress has been made in detailing the biophysical properties and identifying the molecular determinants of these discrete Nav current components, as well as defining their roles in the regulation of Purkinje neuron excitability. Here, we review this important work and highlight the remaining questions about the molecular mechanisms controlling the expression and the functioning of Nav currents in Purkinje neurons. We also discuss the impact of the dynamic regulation of Nav currents on the functioning of individual Purkinje neurons and cerebellar circuits.
Collapse
Affiliation(s)
- Joseph L Ransdell
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Medicine, Washington University School of Medicine, Box 8086, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
| | - Jeanne M Nerbonne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Medicine, Washington University School of Medicine, Box 8086, 660 South Euclid Avenue, St. Louis, MO, 63110, USA.
| |
Collapse
|
26
|
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.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Musaad Alshammari
- King Saud University Graduate Studies Abroad Program, King Saud University, Riyadh, Saudi Arabia
| | | | | | | | | |
Collapse
|
27
|
Symonds JD, Zuberi SM. Genetics update: Monogenetics, polygene disorders and the quest for modifying genes. Neuropharmacology 2017; 132:3-19. [PMID: 29037745 DOI: 10.1016/j.neuropharm.2017.10.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 10/09/2017] [Accepted: 10/11/2017] [Indexed: 12/19/2022]
Abstract
The genetic channelopathies are a broad collection of diseases. Many ion channel genes demonstrate wide phenotypic pleiotropy, but nonetheless concerted efforts have been made to characterise genotype-phenotype relationships. In this review we give an overview of the factors that influence genotype-phenotype relationships across this group of diseases as a whole, using specific individual channelopathies as examples. We suggest reasons for the limitations observed in these relationships. We discuss the role of ion channel variation in polygenic disease and highlight research that has contributed to unravelling the complex aetiological nature of these conditions. We focus specifically on the quest for modifying genes in inherited channelopathies, using the voltage-gated sodium channels as an example. Epilepsy related to genetic channelopathy is one area in which precision medicine is showing promise. We will discuss the successes and limitations of precision medicine in these conditions. This article is part of the Special Issue entitled 'Channelopathies.'
Collapse
Affiliation(s)
- Joseph D Symonds
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Queen Elizabeth University Hospitals, Glasgow, UK; School of Medicine, University of Glasgow, Glasgow, UK
| | - Sameer M Zuberi
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Queen Elizabeth University Hospitals, Glasgow, UK; School of Medicine, University of Glasgow, Glasgow, UK.
| |
Collapse
|
28
|
Symonds JD, Zuberi SM. WITHDRAWN: Genetics update: Monogenetics, polygene disorders and the quest for modifying genes. Neuropharmacology 2017:S0028-3908(17)30347-7. [PMID: 28757052 DOI: 10.1016/j.neuropharm.2017.07.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 07/17/2017] [Indexed: 11/15/2022]
Abstract
The Publisher regrets that this article is an accidental duplication of an article that has already been published, https://doi.org/10.1016/j.neuropharm.2017.10.013. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.
Collapse
Affiliation(s)
- Joseph D Symonds
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Queen Elizabeth University Hospitals, Glasgow, UK; School of Medicine, University of Glasgow, Glasgow, UK
| | - Sameer M Zuberi
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Queen Elizabeth University Hospitals, Glasgow, UK; School of Medicine, University of Glasgow, Glasgow, UK
| |
Collapse
|
29
|
Barbosa C, Xiao Y, Johnson AJ, Xie W, Strong JA, Zhang JM, Cummins TR. FHF2 isoforms differentially regulate Nav1.6-mediated resurgent sodium currents in dorsal root ganglion neurons. Pflugers Arch 2016; 469:195-212. [PMID: 27999940 DOI: 10.1007/s00424-016-1911-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 10/19/2016] [Accepted: 11/20/2016] [Indexed: 10/20/2022]
Abstract
Nav1.6 and Nav1.6-mediated resurgent currents have been implicated in several pain pathologies. However, our knowledge of how fast resurgent currents are modulated in neurons is limited. Our study explored the potential regulation of Nav1.6-mediated resurgent currents by isoforms of fibroblast growth factor homologous factor 2 (FHF2) in an effort to address the gap in our knowledge. FHF2 isoforms colocalize with Nav1.6 in peripheral sensory neurons. Cell line studies suggest that these proteins differentially regulate inactivation. In particular, FHF2A mediates long-term inactivation, a mechanism proposed to compete with the open-channel blocker mechanism that mediates resurgent currents. On the other hand, FHF2B lacks the ability to mediate long-term inactivation and may delay inactivation favoring open-channel block. Based on these observations, we hypothesized that FHF2A limits resurgent currents, whereas FHF2B enhances resurgent currents. Overall, our results suggest that FHF2A negatively regulates fast resurgent current by enhancing long-term inactivation and delaying recovery. In contrast, FHF2B positively regulated resurgent current and did not alter long-term inactivation. Chimeric constructs of FHF2A and Navβ4 (likely the endogenous open channel blocker in sensory neurons) exhibited differential effects on resurgent currents, suggesting that specific regions within FHF2A and Navβ4 have important regulatory functions. Our data also indicate that FHFAs and FHF2B isoform expression are differentially regulated in a radicular pain model and that associated neuronal hyperexcitability is substantially attenuated by a FHFA peptide. As such, these findings suggest that FHF2A and FHF2B regulate resurgent current in sensory neurons and may contribute to hyperexcitability associated with some pain pathologies.
Collapse
Affiliation(s)
- Cindy Barbosa
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA.,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yucheng Xiao
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA.,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrew J Johnson
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA.,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Wenrui Xie
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA
| | - Judith A Strong
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA
| | - Jun-Ming Zhang
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA
| | - Theodore R Cummins
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA. .,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA. .,Department of Biology, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA.
| |
Collapse
|
30
|
Al-Mehmadi S, Splitt M, Ramesh V, DeBrosse S, Dessoffy K, Xia F, Yang Y, Rosenfeld JA, Cossette P, Michaud JL, Hamdan FF, Campeau PM, Minassian BA. FHF1 (FGF12) epileptic encephalopathy. NEUROLOGY-GENETICS 2016; 2:e115. [PMID: 27830185 PMCID: PMC5087254 DOI: 10.1212/nxg.0000000000000115] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/29/2016] [Indexed: 01/29/2023]
Abstract
Voltage-gated sodium channels (Navs) are mainstays of neuronal function, and mutations in the genes encoding CNS Navs (Nav1.1 [SCN1A], Nav1.2 [SCN2A], Nav1.3 [SCN3A], and Nav1.6 [SCN8A]) are causes of some of the most common and severe genetic epilepsies and epileptic encephalopathies (EE).1 Fibroblast-growth-factor homologous factors (FHFs) compose a family of 4 proteins that interact with the C-terminal tails of Navs to modulate the channels' fast, and long-term, inactivations.2FHF2 mutation is a rare cause of generalized epilepsy with febrile seizures plus (GEFS+).3 Recently, a de novo FHF1 mutation (p.R52H) was reported in early-onset EE in 2 siblings.4 We report 3 patients from unrelated families with the same FHF1 p.R52H mutation. The 5 cases together frame the FHF1 R52H EE from infancy to adulthood. As discussed below, this gain-of-function disease may be amenable to personalized therapy.
Collapse
Affiliation(s)
- Sameer Al-Mehmadi
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | - Miranda Splitt
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | | | - Venkateswaran Ramesh
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | - Suzanne DeBrosse
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | - Kimberly Dessoffy
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | - Fan Xia
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | - Yaping Yang
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | - Jill A Rosenfeld
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | - Patrick Cossette
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | - Jacques L Michaud
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | - Fadi F Hamdan
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | - Philippe M Campeau
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | - Berge A Minassian
- Program in Genetics and Genome Biology and Division of Neurology (S.A.-M., B.A.M.), Department of Paediatrics, The Hospital for Sick Children, and University of Toronto, Ontario, Canada; Institute of Genetic Medicine (M.S.), International Centre for Life, Pediatric Neurology (V.R.), Newcastle General Hospital, UK; Center for Human Genetics (S.D., K.D.), UH Case Medical Center, Cleveland, OH; Department of Molecular and Human Genetics (F.X., Y.Y., J.A.R.), Baylor College of Medicine, Houston, TX; Baylor Miraca Genetics Laboratories (F.X., Y.Y.), Houston, TX; The Deciphering Developmental Disorders (DDD) Study, Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK; Division of Neurology (P.C.), CHUM Notre-Dame, Hospital University of Montreal, Quebec, Canada; Department of Pediatrics (J.L.M., P.M.C.), Department of Neurosciences (J.L.M., P.M.C.), Université de Montréal, Québec, Canada; and CHU Sainte-Justine Research Center (J.L.M., F.A.H., P.M.C.), Montreal, Quebec, Canada
| | | |
Collapse
|
31
|
Yang J, Wang Z, Sinden DS, Wang X, Shan B, Yu X, Zhang H, Pitt GS, Wang C. FGF13 modulates the gating properties of the cardiac sodium channel Na v1.5 in an isoform-specific manner. Channels (Austin) 2016; 10:410-420. [PMID: 27246624 DOI: 10.1080/19336950.2016.1190055] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
FGF13 (FHF2), the major fibroblast growth factor homologous factor (FHF) in rodent heart, directly binds to the C-terminus of the main cardiac sodium channel, NaV1.5. Knockdown of FGF13 in cardiomyocytes induces slowed ventricular conduction by altering NaV1.5 function. FGF13 has five splice variants, each of which possess the same core region and C terminus but differing in their respective N termini. Whether and how these alternatively spliced N termini impart isoform-specific regulation of NaV1.5, however, has not been reported. Here, we exploited a heterologous expression to explore the specific modulatory effects of FGF13 splice variants FGF13S, FGF13U and FGF13YV on NaV1.5 function. We found these three splice variants differentially modulated NaV1.5 current density. Although steady-state activation was unaltered by any of the FGF13 isoforms (compared to control cells expressing Nav1.5 but not expressing FGF13), open-state fast inactivation and closed-state fast inactivation were markedly slowed, steady-state availability was significantly shifted toward the depolarizing direction, and the window current was increased by each of FGF13 isoforms. Most strikingly, FGF13S hastened the rate of NaV1.5 entry into the slow inactivation state and induced a dramatic slowing of recovery from inactivation, which caused a large decrease in current after either low or high frequency stimulation. Overall, these data showed the diversity of the roles of the FGF13 N-termini in NaV1.5 channel modulation and suggested the importance of isoform-specific regulation.
Collapse
Affiliation(s)
- Jing Yang
- a Department of Physiology , Hebei Medical University , Shijiazhuang , Hebei , China
| | - Zhihua Wang
- b Department of Pharmacology , Hebei Medical University , Shijiazhuang , Hebei , China
| | - Daniel S Sinden
- c Department of Medicine/Cardiology and Pharmacology , Ion Channel Research Unit, Duke University Medical Center , Durham , NC , USA
| | - Xiangchong Wang
- b Department of Pharmacology , Hebei Medical University , Shijiazhuang , Hebei , China
| | - Bin Shan
- b Department of Pharmacology , Hebei Medical University , Shijiazhuang , Hebei , China
| | - Xiao Yu
- d Department of Physiology , Shandong University, School of Medicine , Jinan , Shandong , China
| | - Hailin Zhang
- b Department of Pharmacology , Hebei Medical University , Shijiazhuang , Hebei , China
| | - Geoffrey S Pitt
- c Department of Medicine/Cardiology and Pharmacology , Ion Channel Research Unit, Duke University Medical Center , Durham , NC , USA
| | - Chuan Wang
- b Department of Pharmacology , Hebei Medical University , Shijiazhuang , Hebei , China
| |
Collapse
|
32
|
Pablo JL, Wang C, Presby MM, Pitt GS. Polarized localization of voltage-gated Na+ channels is regulated by concerted FGF13 and FGF14 action. Proc Natl Acad Sci U S A 2016; 113:E2665-74. [PMID: 27044086 PMCID: PMC4868475 DOI: 10.1073/pnas.1521194113] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Clustering of voltage-gated sodium channels (VGSCs) within the neuronal axon initial segment (AIS) is critical for efficient action potential initiation. Although initially inserted into both somatodendritic and axonal membranes, VGSCs are concentrated within the axon through mechanisms that include preferential axonal targeting and selective somatodendritic endocytosis. How the endocytic machinery specifically targets somatic VGSCs is unknown. Here, using knockdown strategies, we show that noncanonical FGF13 binds directly to VGSCs in hippocampal neurons to limit their somatodendritic surface expression, although exerting little effect on VGSCs within the AIS. In contrast, homologous FGF14, which is highly concentrated in the proximal axon, binds directly to VGSCs to promote their axonal localization. Single-point mutations in FGF13 or FGF14 abrogating VGSC interaction in vitro cannot support these specific functions in neurons. Thus, our data show how the concerted actions of FGF13 and FGF14 regulate the polarized localization of VGSCs that supports efficient action potential initiation.
Collapse
Affiliation(s)
- Juan Lorenzo Pablo
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710; Ion Channel Research Unit, Duke University Medical Center, Durham, NC 27710
| | - Chaojian Wang
- Ion Channel Research Unit, Duke University Medical Center, Durham, NC 27710; Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, NC 27710
| | - Matthew M Presby
- Ion Channel Research Unit, Duke University Medical Center, Durham, NC 27710; Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, NC 27710
| | - Geoffrey S Pitt
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710; Ion Channel Research Unit, Duke University Medical Center, Durham, NC 27710; Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, NC 27710
| |
Collapse
|
33
|
Siekierska A, Isrie M, Liu Y, Scheldeman C, Vanthillo N, Lagae L, de Witte PAM, Van Esch H, Goldfarb M, Buyse GM. Gain-of-function FHF1 mutation causes early-onset epileptic encephalopathy with cerebellar atrophy. Neurology 2016; 86:2162-70. [PMID: 27164707 DOI: 10.1212/wnl.0000000000002752] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/12/2016] [Indexed: 01/30/2023] Open
Abstract
OBJECTIVE Voltage-gated sodium channel (Nav)-encoding genes are among early-onset epileptic encephalopathies (EOEE) targets, suggesting that other genes encoding Nav-binding proteins, such as fibroblast growth factor homologous factors (FHFs), may also play roles in these disorders. METHODS To identify additional genes for EOEE, we performed whole-exome sequencing in a family quintet with 2 siblings with a lethal disease characterized by EOEE and cerebellar atrophy. The pathogenic nature and functional consequences of the identified sequence alteration were determined by electrophysiologic studies in vitro and in vivo. RESULTS A de novo heterozygous missense mutation was identified in the FHF1 gene (FHF1AR114H, FHF1BR52H) in the 2 affected siblings. The mutant FHF1 proteins had a strong gain-of-function phenotype in transfected Neuro2A cells, enhancing the depolarizing shifts in Nav1.6 voltage-dependent fast inactivation, predicting increased neuronal excitability. Surprisingly, the gain-of-function effect is predicted to result from weaker interaction of mutant FHF1 with the Nav cytoplasmic tail. Transgenic overexpression of mutant FHF1B in zebrafish larvae enhanced epileptiform discharges, demonstrating the epileptic potential of this FHF1 mutation in the affected children. CONCLUSIONS Our data demonstrate that gain-of-function FHF mutations can cause neurologic disorder, and expand the repertoire of genetic causes (FHF1) and mechanisms (altered Nav gating) underlying EOEE and cerebellar atrophy.
Collapse
Affiliation(s)
- Aleksandra Siekierska
- From the Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences (A.S., C.S., N.V., P.A.M.d.W.), and Laboratory for the Genetics of Cognition (M.I.), University of Leuven; Center for Human Genetics (M.I., H.V.E.) and Child Neurology (L.L., G.M.B.), University Hospitals Leuven; Department of Biological Sciences (Y.L., M.G.), Hunter College of City University, New York; and Graduate Program in Biology/Neuroscience at City University (Y.L.), New York, NY
| | - Mala Isrie
- From the Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences (A.S., C.S., N.V., P.A.M.d.W.), and Laboratory for the Genetics of Cognition (M.I.), University of Leuven; Center for Human Genetics (M.I., H.V.E.) and Child Neurology (L.L., G.M.B.), University Hospitals Leuven; Department of Biological Sciences (Y.L., M.G.), Hunter College of City University, New York; and Graduate Program in Biology/Neuroscience at City University (Y.L.), New York, NY
| | - Yue Liu
- From the Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences (A.S., C.S., N.V., P.A.M.d.W.), and Laboratory for the Genetics of Cognition (M.I.), University of Leuven; Center for Human Genetics (M.I., H.V.E.) and Child Neurology (L.L., G.M.B.), University Hospitals Leuven; Department of Biological Sciences (Y.L., M.G.), Hunter College of City University, New York; and Graduate Program in Biology/Neuroscience at City University (Y.L.), New York, NY
| | - Chloë Scheldeman
- From the Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences (A.S., C.S., N.V., P.A.M.d.W.), and Laboratory for the Genetics of Cognition (M.I.), University of Leuven; Center for Human Genetics (M.I., H.V.E.) and Child Neurology (L.L., G.M.B.), University Hospitals Leuven; Department of Biological Sciences (Y.L., M.G.), Hunter College of City University, New York; and Graduate Program in Biology/Neuroscience at City University (Y.L.), New York, NY
| | - Niels Vanthillo
- From the Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences (A.S., C.S., N.V., P.A.M.d.W.), and Laboratory for the Genetics of Cognition (M.I.), University of Leuven; Center for Human Genetics (M.I., H.V.E.) and Child Neurology (L.L., G.M.B.), University Hospitals Leuven; Department of Biological Sciences (Y.L., M.G.), Hunter College of City University, New York; and Graduate Program in Biology/Neuroscience at City University (Y.L.), New York, NY
| | - Lieven Lagae
- From the Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences (A.S., C.S., N.V., P.A.M.d.W.), and Laboratory for the Genetics of Cognition (M.I.), University of Leuven; Center for Human Genetics (M.I., H.V.E.) and Child Neurology (L.L., G.M.B.), University Hospitals Leuven; Department of Biological Sciences (Y.L., M.G.), Hunter College of City University, New York; and Graduate Program in Biology/Neuroscience at City University (Y.L.), New York, NY
| | - Peter A M de Witte
- From the Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences (A.S., C.S., N.V., P.A.M.d.W.), and Laboratory for the Genetics of Cognition (M.I.), University of Leuven; Center for Human Genetics (M.I., H.V.E.) and Child Neurology (L.L., G.M.B.), University Hospitals Leuven; Department of Biological Sciences (Y.L., M.G.), Hunter College of City University, New York; and Graduate Program in Biology/Neuroscience at City University (Y.L.), New York, NY
| | - Hilde Van Esch
- From the Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences (A.S., C.S., N.V., P.A.M.d.W.), and Laboratory for the Genetics of Cognition (M.I.), University of Leuven; Center for Human Genetics (M.I., H.V.E.) and Child Neurology (L.L., G.M.B.), University Hospitals Leuven; Department of Biological Sciences (Y.L., M.G.), Hunter College of City University, New York; and Graduate Program in Biology/Neuroscience at City University (Y.L.), New York, NY
| | - Mitchell Goldfarb
- From the Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences (A.S., C.S., N.V., P.A.M.d.W.), and Laboratory for the Genetics of Cognition (M.I.), University of Leuven; Center for Human Genetics (M.I., H.V.E.) and Child Neurology (L.L., G.M.B.), University Hospitals Leuven; Department of Biological Sciences (Y.L., M.G.), Hunter College of City University, New York; and Graduate Program in Biology/Neuroscience at City University (Y.L.), New York, NY
| | - Gunnar M Buyse
- From the Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences (A.S., C.S., N.V., P.A.M.d.W.), and Laboratory for the Genetics of Cognition (M.I.), University of Leuven; Center for Human Genetics (M.I., H.V.E.) and Child Neurology (L.L., G.M.B.), University Hospitals Leuven; Department of Biological Sciences (Y.L., M.G.), Hunter College of City University, New York; and Graduate Program in Biology/Neuroscience at City University (Y.L.), New York, NY.
| |
Collapse
|
34
|
Barbosa C, Cummins TR. Unusual Voltage-Gated Sodium Currents as Targets for Pain. CURRENT TOPICS IN MEMBRANES 2016; 78:599-638. [PMID: 27586296 DOI: 10.1016/bs.ctm.2015.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Pain is a serious health problem that impacts the lives of many individuals. Hyperexcitability of peripheral sensory neurons contributes to both acute and chronic pain syndromes. Because voltage-gated sodium currents are crucial to the transmission of electrical signals in peripheral sensory neurons, the channels that underlie these currents are attractive targets for pain therapeutics. Sodium currents and channels in peripheral sensory neurons are complex. Multiple-channel isoforms contribute to the macroscopic currents in nociceptive sensory neurons. These different isoforms exhibit substantial variations in their kinetics and pharmacology. Furthermore, sodium current complexity is enhanced by an array of interacting proteins that can substantially modify the properties of voltage-gated sodium channels. Resurgent sodium currents, atypical currents that can enhance recovery from inactivation and neuronal firing, are increasingly being recognized as playing potentially important roles in sensory neuron hyperexcitability and pain sensations. Here we discuss unusual sodium channels and currents that have been identified in nociceptive sensory neurons, describe what is known about the molecular determinants of the complex sodium currents in these neurons. Finally, we provide an overview of therapeutic strategies to target voltage-gated sodium currents in nociceptive neurons.
Collapse
Affiliation(s)
- C Barbosa
- Indiana University School of Medicine, Indianapolis, IN, United States
| | - T R Cummins
- Indiana University School of Medicine, Indianapolis, IN, United States
| |
Collapse
|
35
|
French CR, Zeng Z, Williams DA, Hill-Yardin EL, O'Brien TJ. Properties of an intermediate-duration inactivation process of the voltage-gated sodium conductance in rat hippocampal CA1 neurons. J Neurophysiol 2016; 115:790-802. [DOI: 10.1152/jn.01000.2014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 11/02/2015] [Indexed: 12/13/2022] Open
Abstract
Rapid transmembrane flow of sodium ions produces the depolarizing phase of action potentials (APs) in most excitable tissue through voltage-gated sodium channels (NaV). Macroscopic currents display rapid activation followed by fast inactivation (IF) within milliseconds. Slow inactivation (IS) has been subsequently observed in several preparations including neuronal tissues. IS serves important physiological functions, but the kinetic properties are incompletely characterized, especially the operative timescales. Here we present evidence for an “intermediate inactivation” (II) process in rat hippocampal CA1 neurons with time constants of the order of 100 ms. The half-inactivation potentials ( V0.5) of steady-state inactivation curves were hyperpolarized by increasing conditioning pulse duration from 50 to 500 ms and could be described by a sum of Boltzmann relations. II state transitions were observed after opening as well as subthreshold potentials. Entry into II after opening was relatively insensitive to membrane potential, and recovery of II became more rapid at hyperpolarized potentials. Removal of fast inactivation with cytoplasmic papaine revealed time constants of INa decay corresponding to II and IS with long depolarizations. Dynamic clamp revealed attenuation of trains of APs over the 102-ms timescale, suggesting a functional role of II in repetitive firing accommodation. These experimental findings could be reproduced with a five-state Markov model. It is likely that II affects important aspects of hippocampal neuron response and may provide a drug target for sodium channel modulation.
Collapse
Affiliation(s)
- Christopher R. French
- Department of Neurobiology, Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia; and
| | - Zhen Zeng
- Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia; and
| | - David A. Williams
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Elisa L. Hill-Yardin
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Terence J. O'Brien
- Department of Neurobiology, Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia; and
| |
Collapse
|
36
|
Gawali V, Todt H. Mechanism of Inactivation in Voltage-Gated Na+ Channels. CURRENT TOPICS IN MEMBRANES 2016; 78:409-50. [DOI: 10.1016/bs.ctm.2016.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
37
|
Mechanisms of FGF gradient formation during embryogenesis. Semin Cell Dev Biol 2015; 53:94-100. [PMID: 26454099 DOI: 10.1016/j.semcdb.2015.10.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/05/2015] [Indexed: 12/17/2022]
Abstract
Fibroblast growth factors (FGFs) have long been attributed to influence morphogenesis in embryonic development. Signaling by FGF morphogen encodes positional identity of tissues by creating a concentration gradient over the developing embryo. Various mechanisms that influence the development of such gradient have been elucidated in the recent past. These mechanisms of FGF gradient formation present either as an extracellular control over FGF ligand diffusion or as a subcellular control of FGF propagation and signaling. In this review, we describe our current understanding of FGF as a morphogen, the extracellular control of FGF gradient formation by heparan sulfate proteoglycans (HSPGs) and mechanisms of intracellular regulation of FGF signaling that influence gradient formation.
Collapse
|
38
|
Disruption of Fgf13 causes synaptic excitatory-inhibitory imbalance and genetic epilepsy and febrile seizures plus. J Neurosci 2015; 35:8866-81. [PMID: 26063919 DOI: 10.1523/jneurosci.3470-14.2015] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We identified a family in which a translocation between chromosomes X and 14 was associated with cognitive impairment and a complex genetic disorder termed "Genetic Epilepsy and Febrile Seizures Plus" (GEFS(+)). We demonstrate that the breakpoint on the X chromosome disrupted a gene that encodes an auxiliary protein of voltage-gated Na(+) channels, fibroblast growth factor 13 (Fgf13). Female mice in which one Fgf13 allele was deleted exhibited hyperthermia-induced seizures and epilepsy. Anatomic studies revealed expression of Fgf13 mRNA in both excitatory and inhibitory neurons of hippocampus. Electrophysiological recordings revealed decreased inhibitory and increased excitatory synaptic inputs in hippocampal neurons of Fgf13 mutants. We speculate that reduced expression of Fgf13 impairs excitability of inhibitory interneurons, resulting in enhanced excitability within local circuits of hippocampus and the clinical phenotype of epilepsy. These findings reveal a novel cause of this syndrome and underscore the powerful role of FGF13 in control of neuronal excitability.
Collapse
|
39
|
Intracellular FGF14 (iFGF14) Is Required for Spontaneous and Evoked Firing in Cerebellar Purkinje Neurons and for Motor Coordination and Balance. J Neurosci 2015; 35:6752-69. [PMID: 25926453 DOI: 10.1523/jneurosci.2663-14.2015] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mutations in FGF14, which encodes intracellular fibroblast growth factor 14 (iFGF14), have been linked to spinocerebellar ataxia (SCA27). In addition, mice lacking Fgf14 (Fgf14(-/-)) exhibit an ataxia phenotype resembling SCA27, accompanied by marked changes in the excitability of cerebellar granule and Purkinje neurons. It is not known, however, whether these phenotypes result from defects in neuronal development or if they reflect a physiological requirement for iFGF14 in the adult cerebellum. Here, we demonstrate that the acute and selective Fgf14-targeted short hairpin RNA (shRNA)-mediated in vivo "knock-down" of iFGF14 in adult Purkinje neurons attenuates spontaneous and evoked action potential firing without measurably affecting the expression or localization of voltage-gated Na(+) (Nav) channels at Purkinje neuron axon initial segments. The selective shRNA-mediated in vivo "knock-down" of iFGF14 in adult Purkinje neurons also impairs motor coordination and balance. Repetitive firing can be restored in Fgf14-targeted shRNA-expressing Purkinje neurons, as well as in Fgf14(-/-) Purkinje neurons, by prior membrane hyperpolarization, suggesting that the iFGF14-mediated regulation of the excitability of mature Purkinje neurons depends on membrane potential. Further experiments revealed that the loss of iFGF14 results in a marked hyperpolarizing shift in the voltage dependence of steady-state inactivation of the Nav currents in adult Purkinje neurons. We also show here that expressing iFGF14 selectively in adult Fgf14(-/-) Purkinje neurons rescues spontaneous firing and improves motor performance. Together, these results demonstrate that iFGF14 is required for spontaneous and evoked action potential firing in adult Purkinje neurons, thereby controlling the output of these cells and the regulation of motor coordination and balance.
Collapse
|
40
|
Detta N, Frisso G, Salvatore F. The multi-faceted aspects of the complex cardiac Nav1.5 protein in membrane function and pathophysiology. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015. [PMID: 26209461 DOI: 10.1016/j.bbapap.2015.07.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The aim of this mini-review is to draw together the main concepts and findings that have emerged from recent studies of the cardiac channel protein Nav1.5. This complex protein is encoded by the SCN5A gene that, in its mutated form, is implicated in various diseases, particularly channelopathies, specifically at cardiac tissue level. Here we describe the structural, and functional aspects of Nav1.5 including post-translational modifications in normal conditions, and the main human channelopathies in which this protein may be the cause or trigger. Lastly, we also briefly discuss interacting proteins that are relevant for these channel functions in normal and disease conditions.
Collapse
Affiliation(s)
- Nicola Detta
- CEINGE-Biotecnologie Avanzate s.c.ar.l., Naples, Italy
| | - Giulia Frisso
- CEINGE-Biotecnologie Avanzate s.c.ar.l., Naples, Italy; Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy
| | - Francesco Salvatore
- CEINGE-Biotecnologie Avanzate s.c.ar.l., Naples, Italy; IRCCS-Fondazione SDN, Naples, Italy.
| |
Collapse
|
41
|
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.
Collapse
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
| |
Collapse
|
42
|
Mapelli J, Gandolfi D, Giuliani E, Prencipe FP, Pellati F, Barbieri A, D’Angelo E, Bigiani A. The effect of desflurane on neuronal communication at a central synapse. PLoS One 2015; 10:e0123534. [PMID: 25849222 PMCID: PMC4388506 DOI: 10.1371/journal.pone.0123534] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 02/24/2015] [Indexed: 11/18/2022] Open
Abstract
Although general anesthetics are thought to modify critical neuronal functions, their impact on neuronal communication has been poorly examined. We have investigated the effect induced by desflurane, a clinically used general anesthetic, on information transfer at the synapse between mossy fibers and granule cells of cerebellum, where this analysis can be carried out extensively. Mutual information values were assessed by measuring the variability of postsynaptic output in relationship to the variability of a given set of presynaptic inputs. Desflurane synchronized granule cell firing and reduced mutual information in response to physiologically relevant mossy fibers patterns. The decrease in spike variability was due to an increased postsynaptic membrane excitability, which made granule cells more prone to elicit action potentials, and to a strengthened synaptic inhibition, which markedly hampered membrane depolarization. These concomitant actions on granule cells firing indicate that desflurane re-shapes the transfer of information between neurons by providing a less informative neurotransmission rather than completely silencing neuronal activity.
Collapse
Affiliation(s)
- Jonathan Mapelli
- Dipartimento di Scienze Biomediche, Metaboliche e Neuroscienze, Università di Modena e Reggio Emilia, Modena, Italy
- * E-mail:
| | - Daniela Gandolfi
- Dipartimento di Scienze Biomediche, Metaboliche e Neuroscienze, Università di Modena e Reggio Emilia, Modena, Italy
- Dipartimento di Scienze del Sistema Nervoso e del Comportamento, Università di Pavia, Pavia, Italy
| | - Enrico Giuliani
- Dipartimento di Medicina Diagnostica, Clinica e di Sanità Pubblica, Università di Modena e Reggio Emilia, Modena, Modena, Italy
| | - Francesco P. Prencipe
- Dipartimento di Scienze della Vita, Università di Modena e Reggio Emilia, Modena, Italy
| | - Federica Pellati
- Dipartimento di Scienze della Vita, Università di Modena e Reggio Emilia, Modena, Italy
| | - Alberto Barbieri
- Dipartimento di Medicina Diagnostica, Clinica e di Sanità Pubblica, Università di Modena e Reggio Emilia, Modena, Modena, Italy
| | - Egidio D’Angelo
- Dipartimento di Scienze del Sistema Nervoso e del Comportamento, Università di Pavia, Pavia, Italy
- Brain Connectivity Center, C. Mondino National Neurological Institute, Pavia, Italy
| | - Albertino Bigiani
- Dipartimento di Scienze Biomediche, Metaboliche e Neuroscienze, Università di Modena e Reggio Emilia, Modena, Italy
| |
Collapse
|
43
|
Singular localization of sodium channel β4 subunit in unmyelinated fibres and its role in the striatum. Nat Commun 2014; 5:5525. [PMID: 25413837 DOI: 10.1038/ncomms6525] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 10/09/2014] [Indexed: 01/15/2023] Open
Abstract
Voltage-gated Na(+) channel β-subunits are multifunctional molecules that modulate Na(+) channel activity and regulate cell adhesion, migration and neurite outgrowth. β-subunits including β4 are known to be highly concentrated in the nodes of Ranvier and axon initial segments in myelinated axons. Here we show diffuse β4 localization in striatal projection fibres using transgenic mice that express fluorescent protein in those fibres. These axons are unmyelinated, forming large, inhibitory fibre bundles. Furthermore, we report β4 dimer expression in the mouse brain, with high levels of β4 dimers in the striatal projection fascicles, suggesting a specific role of β4 in those fibres. Scn4b-deficient mice show a resurgent Na(+) current reduction, decreased repetitive firing frequency in medium spiny neurons and increased failure rates of inhibitory postsynaptic currents evoked with repetitive stimulation, indicating an in vivo channel regulatory role of β4 in the striatum.
Collapse
|
44
|
Itoh N, Ohta H. Pathophysiological roles of FGF signaling in the heart. Front Physiol 2013; 4:247. [PMID: 24046748 PMCID: PMC3764331 DOI: 10.3389/fphys.2013.00247] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 08/21/2013] [Indexed: 01/18/2023] Open
Abstract
Cardiac remodeling progresses to heart failure, which represents a major cause of morbidity and mortality. Cardiomyokines, cardiac secreted proteins, may play roles in cardiac remodeling. Fibroblast growth factors (FGFs) are secreted proteins with diverse functions, mainly in development and metabolism. However, some FGFs play pathophysiological roles in cardiac remodeling as cardiomyokines. FGF2 promotes cardiac hypertrophy and fibrosis by activating MAPK signaling through the activation of FGF receptor (FGFR) 1c. In contrast, FGF16 may prevent these by competing with FGF2 for the binding site of FGFR1c. FGF21 prevents cardiac hypertrophy by activating MAPK signaling through the activation of FGFR1c with β-Klotho as a co-receptor. In contrast, FGF23 induces cardiac hypertrophy by activating calcineurin/NFAT signaling without αKlotho. These FGFs play crucial roles in cardiac remodeling via distinct action mechanisms. These findings provide new insights into the pathophysiological roles of FGFs in the heart and may provide potential therapeutic strategies for heart failure.
Collapse
Affiliation(s)
- Nobuyuki Itoh
- Department of Genetic Biochemistry, Kyoto University Graduate School of Pharmaceutical Sciences Kyoto, Japan
| | | |
Collapse
|
45
|
Matsuo I, Kimura-Yoshida C. Extracellular modulation of Fibroblast Growth Factor signaling through heparan sulfate proteoglycans in mammalian development. Curr Opin Genet Dev 2013; 23:399-407. [PMID: 23465883 DOI: 10.1016/j.gde.2013.02.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 02/04/2013] [Accepted: 02/07/2013] [Indexed: 12/27/2022]
Abstract
Fibroblast Growth Factor (FGF) signaling plays crucial roles in multiple cellular processes including cell proliferation, differentiation, survival, and migration during mammalian embryogenesis. In the extracellular matrix, as well as at the cell surface, the movement of FGF ligands to target cells and the subsequent complex formations with their receptors are positively and negatively controlled extracellularly by heparan sulfate proteoglycans (HSPGs) such as syndecans, glypicans, and perlecan. Additionally, spreading of HSPGs by cleavage with sheddases such as proteinases and heparanases, and the overall length and sulfation level of specific heparan sulfate structures further generate a great diversity of FGF signaling outcomes. This review presents our current understanding of the regulatory mechanisms of FGF signaling in extracellular spaces through HSPGs in mammalian development.
Collapse
Affiliation(s)
- Isao Matsuo
- Department of Molecular Embryology, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka Prefectural Hospital Organization, 840 Murodo-cho, Izumi, Osaka 594-1101, Japan.
| | | |
Collapse
|
46
|
Savio-Galimberti E, Gollob MH, Darbar D. Voltage-gated sodium channels: biophysics, pharmacology, and related channelopathies. Front Pharmacol 2012; 3:124. [PMID: 22798951 PMCID: PMC3394224 DOI: 10.3389/fphar.2012.00124] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 06/11/2012] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (VGSC) are multi-molecular protein complexes expressed in both excitable and non-excitable cells. They are primarily formed by a pore-forming multi-spanning integral membrane glycoprotein (α-subunit) that can be associated with one or more regulatory β-subunits. The latter are single-span integral membrane proteins that modulate the sodium current (INa) and can also function as cell adhesion molecules. In vitro some of the cell-adhesive functions of the β-subunits may play important physiological roles independently of the α-subunits. Other endogenous regulatory proteins named “channel partners” or “channel interacting proteins” (ChiPs) like caveolin-3 and calmodulin/calmodulin kinase II (CaMKII) can also interact and modulate the expression and/or function of VGSC. In addition to their physiological roles in cell excitability and cell adhesion, VGSC are the site of action of toxins (like tetrodotoxin and saxitoxin), and pharmacologic agents (like antiarrhythmic drugs, local anesthetics, antiepileptic drugs, and newly developed analgesics). Mutations in genes that encode α- and/or β-subunits as well as the ChiPs can affect the structure and biophysical properties of VGSC, leading to the development of diseases termed sodium “channelopathies”. This review will outline the structure, function, and biophysical properties of VGSC as well as their pharmacology and associated channelopathies and highlight some of the recent advances in this field.
Collapse
Affiliation(s)
- Eleonora Savio-Galimberti
- Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Nashville, TN, USA
| | | | | |
Collapse
|
47
|
Marchant JS, Lin-Moshier Y, Walseth TF, Patel S. The Molecular Basis for Ca 2+ Signalling by NAADP: Two-Pore Channels in a Complex? ACTA ACUST UNITED AC 2012; 1:63-76. [PMID: 25309835 DOI: 10.1166/msr.2012.1003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
NAADP is a potent Ca2+ mobilizing messenger in a variety of cells but its molecular mechanism of action is incompletely understood. Accumulating evidence indicates that the poorly characterized two-pore channels (TPCs) in animals are NAADP sensitive Ca2+-permeable channels. TPCs localize to the endo-lysosomal system but are functionally coupled to the better characterized endoplasmic reticulum Ca2+ channels to generate physiologically relevant complex Ca2+ signals. Whether TPCs directly bind NAADP is not clear. Here we discuss the idea based on recent studies that TPCs are the pore-forming subunits of a protein complex that includes tightly associated, low molecular weight NAADP-binding proteins.
Collapse
Affiliation(s)
- Jonathan S Marchant
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Yaping Lin-Moshier
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Timothy F Walseth
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, UK
| |
Collapse
|