1
|
Yuan Y, Lopez-Santiago L, Denomme N, Chen C, O'Malley HA, Hodges SL, Ji S, Han Z, Christiansen A, Isom LL. Antisense oligonucleotides restore excitability, GABA signalling and sodium current density in a Dravet syndrome model. Brain 2024; 147:1231-1246. [PMID: 37812817 PMCID: PMC10994531 DOI: 10.1093/brain/awad349] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/13/2023] [Accepted: 09/27/2023] [Indexed: 10/11/2023] Open
Abstract
Dravet syndrome is an intractable developmental and epileptic encephalopathy caused by de novo variants in SCN1A resulting in haploinsufficiency of the voltage-gated sodium channel Nav1.1. We showed previously that administration of the antisense oligonucleotide STK-001, also called ASO-22, generated using targeted augmentation of nuclear gene output technology to prevent inclusion of the nonsense-mediated decay, or poison, exon 20N in human SCN1A, increased productive Scn1a transcript and Nav1.1 expression and reduced the incidence of electrographic seizures and sudden unexpected death in epilepsy in a mouse model of Dravet syndrome. Here, we investigated the mechanism of action of ASO-84, a surrogate for ASO-22 that also targets splicing of SCN1A exon 20N, in Scn1a+/- Dravet syndrome mouse brain. Scn1a +/- Dravet syndrome and wild-type mice received a single intracerebroventricular injection of antisense oligonucleotide or vehicle at postnatal Day 2. We examined the electrophysiological properties of cortical pyramidal neurons and parvalbumin-positive fast-spiking interneurons in brain slices at postnatal Days 21-25 and measured sodium currents in parvalbumin-positive interneurons acutely dissociated from postnatal Day 21-25 brain slices. We show that, in untreated Dravet syndrome mice, intrinsic cortical pyramidal neuron excitability was unchanged while cortical parvalbumin-positive interneurons showed biphasic excitability with initial hyperexcitability followed by hypoexcitability and depolarization block. Dravet syndrome parvalbumin-positive interneuron sodium current density was decreased compared to wild-type. GABAergic signalling to cortical pyramidal neurons was reduced in Dravet syndrome mice, suggesting decreased GABA release from interneurons. ASO-84 treatment restored action potential firing, sodium current density and GABAergic signalling in Dravet syndrome parvalbumin-positive interneurons. Our work suggests that interneuron excitability is selectively affected by ASO-84. This new work provides critical insights into the mechanism of action of this antisense oligonucleotide and supports the potential of antisense oligonucleotide-mediated upregulation of Nav1.1 as a successful strategy to treat Dravet syndrome.
Collapse
Affiliation(s)
- Yukun Yuan
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Luis Lopez-Santiago
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicholas Denomme
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Chunling Chen
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Heather A O'Malley
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Samantha L Hodges
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sophina Ji
- Stoke Therapeutics, Inc., Bedford, MA 01730, USA
| | - Zhou Han
- Stoke Therapeutics, Inc., Bedford, MA 01730, USA
| | | | - Lori L Isom
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| |
Collapse
|
2
|
Nelson AD, Catalfio AM, Gupta JP, Min L, Caballero-Florán RN, Dean KP, Elvira CC, Derderian KD, Kyoung H, Sahagun A, Sanders SJ, Bender KJ, Jenkins PM. Physical and functional convergence of the autism risk genes Scn2a and Ank2 in neocortical pyramidal cell dendrites. Neuron 2024; 112:1133-1149.e6. [PMID: 38290518 DOI: 10.1016/j.neuron.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 04/26/2023] [Accepted: 01/03/2024] [Indexed: 02/01/2024]
Abstract
Dysfunction in sodium channels and their ankyrin scaffolding partners have both been implicated in neurodevelopmental disorders, including autism spectrum disorder (ASD). In particular, the genes SCN2A, which encodes the sodium channel NaV1.2, and ANK2, which encodes ankyrin-B, have strong ASD association. Recent studies indicate that ASD-associated haploinsufficiency in Scn2a impairs dendritic excitability and synaptic function in neocortical pyramidal cells, but how NaV1.2 is anchored within dendritic regions is unknown. Here, we show that ankyrin-B is essential for scaffolding NaV1.2 to the dendritic membrane of mouse neocortical neurons and that haploinsufficiency of Ank2 phenocopies intrinsic dendritic excitability and synaptic deficits observed in Scn2a+/- conditions. These results establish a direct, convergent link between two major ASD risk genes and reinforce an emerging framework suggesting that neocortical pyramidal cell dendritic dysfunction can contribute to neurodevelopmental disorder pathophysiology.
Collapse
Affiliation(s)
- Andrew D Nelson
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Amanda M Catalfio
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Julie P Gupta
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Lia Min
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Kendall P Dean
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Carina C Elvira
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kimberly D Derderian
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Henry Kyoung
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Atehsa Sahagun
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Stephan J Sanders
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Psychiatry, University of California, San Francisco, San Francisco, CA, USA
| | - Kevin J Bender
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
| | - Paul M Jenkins
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI, USA.
| |
Collapse
|
3
|
Jansen NA, Cestèle S, Marco SS, Schenke M, Stewart K, Patel J, Tolner EA, Brunklaus A, Mantegazza M, van den Maagdenberg AMJM. Brainstem depolarization-induced lethal apnea associated with gain-of-function SCN1AL263V is prevented by sodium channel blockade. Proc Natl Acad Sci U S A 2024; 121:e2309000121. [PMID: 38547067 PMCID: PMC10998578 DOI: 10.1073/pnas.2309000121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 02/21/2024] [Indexed: 04/02/2024] Open
Abstract
Apneic events are frightening but largely benign events that often occur in infants. Here, we report apparent life-threatening apneic events in an infant with the homozygous SCN1AL263V missense mutation, which causes familial hemiplegic migraine type 3 in heterozygous family members, in the absence of epilepsy. Observations consistent with the events in the infant were made in an Scn1aL263V knock-in mouse model, in which apnea was preceded by a large brainstem DC-shift, indicative of profound brainstem depolarization. The L263V mutation caused gain of NaV1.1 function effects in transfected HEK293 cells. Sodium channel blockade mitigated the gain-of-function characteristics, rescued lethal apnea in Scn1aL263V mice, and decreased the frequency of severe apneic events in the patient. Hence, this study shows that SCN1AL263V can cause life-threatening apneic events, which in a mouse model were caused by profound brainstem depolarization. In addition to being potentially relevant to sudden infant death syndrome pathophysiology, these data indicate that sodium channel blockers may be considered therapeutic for apneic events in patients with these and other gain-of-function SCN1A mutations.
Collapse
Affiliation(s)
- Nico A. Jansen
- Department of Human Genetics, Leiden University Medical Center, Leiden2333 ZC, The Netherlands
| | - Sandrine Cestèle
- Université Côte d’Azur, Valbonne-Sophia Antipolis06560, France
- Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis06560, France
| | - Silvia Sanchez Marco
- Department of Paediatric Neurology, Bristol Royal Hospital for Children, University Hospitals Bristol, BristolBS2 8BJ, United Kingdom
| | - Maarten Schenke
- Department of Human Genetics, Leiden University Medical Center, Leiden2333 ZC, The Netherlands
| | - Kirsty Stewart
- West of Scotland Genetic Services, Queen Elizabeth University Hospital, GlasgowG51 4TF, United Kingdom
| | - Jayesh Patel
- Department of Paediatric Neurology, Bristol Royal Hospital for Children, University Hospitals Bristol, BristolBS2 8BJ, United Kingdom
| | - Else A. Tolner
- Department of Human Genetics, Leiden University Medical Center, Leiden2333 ZC, The Netherlands
- Department of Neurology, Leiden University Medical Center, Leiden2333 ZA, The Netherlands
| | - Andreas Brunklaus
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, GlasgowG51 4TF, United Kingdom
- School of Health and Wellbeing, University of Glasgow, GlasgowG12 8TB, United Kingdom
| | - Massimo Mantegazza
- Université Côte d’Azur, Valbonne-Sophia Antipolis06560, France
- Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis06560, France
- Inserm, Valbonne-Sophia Antipolis06560, France
| | - Arn M. J. M. van den Maagdenberg
- Department of Human Genetics, Leiden University Medical Center, Leiden2333 ZC, The Netherlands
- Department of Neurology, Leiden University Medical Center, Leiden2333 ZA, The Netherlands
| |
Collapse
|
4
|
Yang Y, Chen Z, Zhou J, Jiang S, Wang G, Wan L, Yu J, Jiang M, Wang Y, Hu J, Liu X, Wang Y. Anti-PD-1 treatment protects against seizure by suppressing sodium channel function. CNS Neurosci Ther 2024; 30:e14504. [PMID: 37904722 PMCID: PMC11017438 DOI: 10.1111/cns.14504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 11/01/2023] Open
Abstract
AIMS Although programmed cell death protein 1 (PD-1) typically serves as a target for immunotherapies, a few recent studies have found that PD-1 is expressed in the nervous system and that neuronal PD-1 might play a crucial role in regulating neuronal excitability. However, whether brain-localized PD-1 is involved in seizures and epileptogenesis is still unknown and worthy of in-depth exploration. METHODS The existence of PD-1 in human neurons was confirmed by immunohistochemistry, and PD-1 expression levels were measured by real-time quantitative PCR (RT-qPCR) and western blotting. Chemoconvulsants, pentylenetetrazol (PTZ) and cyclothiazide (CTZ), were applied for the establishment of in vivo (rodents) and in vitro (primary hippocampal neurons) models of seizure, respectively. SHR-1210 (a PD-1 monoclonal antibody) and sodium stibogluconate (SSG, a validated inhibitor of SH2-containing protein tyrosine phosphatase-1 [SHP-1]) were administrated to investigate the impact of PD-1 pathway blockade on epileptic behaviors of rodents and epileptiform discharges of neurons. A miRNA strategy was applied to determine the impact of PD-1 knockdown on neuronal excitability. The electrical activities and sodium channel function of neurons were determined by whole-cell patch-clamp recordings. The interaction between PD-1 and α-6 subunit of human voltage-gated sodium channel (Nav1.6) was validated by performing co-immunostaining and co-immunoprecipitation (co-IP) experiments. RESULTS Our results reveal that PD-1 protein and mRNA levels were upregulated in lesion cores compared with perifocal tissues of surgically resected specimens from patients with intractable epilepsy. Furthermore, we show that anti-PD-1 treatment has anti-seizure effects both in vivo and in vitro. Then, we reveal that PD-1 blockade can alter the electrophysiological properties of sodium channels. Moreover, we reveal that PD-1 acts together with downstream SHP-1 to regulate sodium channel function and hence neuronal excitability. Further investigation suggests that there is a direct interaction between neuronal PD-1 and Nav1.6. CONCLUSION Our study reveals that neuronal PD-1 plays an important role in epilepsy and that anti-PD-1 treatment protects against seizures by suppressing sodium channel function, identifying anti-PD-1 treatment as a novel therapeutic strategy for epilepsy.
Collapse
Affiliation(s)
- Yuling Yang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Zhiyun Chen
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Jing Zhou
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
- Rehabilitation CenterShenzhen Second People's Hospital/The First Affiliated Hospital of Shenzhen University Health Science CenterShenzhenChina
| | - Shize Jiang
- Department of Neurosurgery, Huashan HospitalFudan UniversityShanghaiChina
| | - Guoxiang Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Li Wan
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
- Rehabilitation CenterShenzhen Second People's Hospital/The First Affiliated Hospital of Shenzhen University Health Science CenterShenzhenChina
| | - Jiangning Yu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Min Jiang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Yulong Wang
- Rehabilitation CenterShenzhen Second People's Hospital/The First Affiliated Hospital of Shenzhen University Health Science CenterShenzhenChina
| | - Jie Hu
- Department of Neurosurgery, Huashan HospitalFudan UniversityShanghaiChina
| | - Xu Liu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan HospitalFudan UniversityShanghaiChina
| |
Collapse
|
5
|
Hingorani S, Paniagua Soriano G, Sánchez Huertas C, Villalba Riquelme EM, López Mocholi E, Martínez Rojas B, Alastrué Agudo A, Dupraz S, Ferrer Montiel AV, Moreno Manzano V. Transplantation of dorsal root ganglia overexpressing the NaChBac sodium channel improves locomotion after complete SCI. Mol Ther 2024:S1525-0016(24)00216-8. [PMID: 38556794 DOI: 10.1016/j.ymthe.2024.03.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/21/2024] [Accepted: 03/28/2024] [Indexed: 04/02/2024] Open
Abstract
Spinal cord injury (SCI) is a debilitating condition currently lacking treatment. Severe SCI causes the loss of most supraspinal inputs and neuronal activity caudal to the injury, which, coupled with the limited endogenous capacity for spontaneous regeneration, can lead to complete functional loss even in anatomically incomplete lesions. We hypothesized that transplantation of mature dorsal root ganglia (DRGs) genetically modified to express the NaChBac sodium channel could serve as a therapeutic option for functionally complete SCI. We found that NaChBac expression increased the intrinsic excitability of DRG neurons and promoted cell survival and neurotrophic factor secretion in vitro. Transplantation of NaChBac-expressing dissociated DRGs improved voluntary locomotion 7 weeks after injury compared to control groups. Animals transplanted with NaChBac-expressing DRGs also possessed higher tubulin-positive neuronal fiber and myelin preservation, although serotonergic descending fibers remained unaffected. We observed early preservation of the corticospinal tract 14 days after injury and transplantation, which was lost 7 weeks after injury. Nevertheless, transplantation of NaChBac-expressing DRGs increased the neuronal excitatory input by an increased number of VGLUT2 contacts immediately caudal to the injury. Our work suggests that the transplantation of NaChBac-expressing dissociated DRGs can rescue significant motor function, retaining an excitatory neuronal relay activity immediately caudal to injury.
Collapse
Affiliation(s)
- Sonia Hingorani
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Guillem Paniagua Soriano
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Carlos Sánchez Huertas
- Development and Assembly of Bilateral Neural Circuits Laboratory, Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Miguel Hernández, Avenida Santiago Ramon y Cajal, s/n, 03550 Sant Joan d'Alacant, Alicante, Spain
| | - Eva María Villalba Riquelme
- Biochemistry and Molecular Biology Department, Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche-IDiBE, Avenida de la Universidad, s/n, Edificio Torregaitán, 03202 Elche, Alicante, Spain
| | - Eric López Mocholi
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Beatriz Martínez Rojas
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Ana Alastrué Agudo
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Sebastián Dupraz
- Laboratory for Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
| | - Antonio Vicente Ferrer Montiel
- Biochemistry and Molecular Biology Department, Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche-IDiBE, Avenida de la Universidad, s/n, Edificio Torregaitán, 03202 Elche, Alicante, Spain
| | - Victoria Moreno Manzano
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain.
| |
Collapse
|
6
|
Goodchild SJ, Shuart NG, Williams AD, Ye W, Parrish RR, Soriano M, Thouta S, Mezeyova J, Waldbrook M, Dean R, Focken T, Ghovanloo MR, Ruben PC, Scott F, Cohen CJ, Empfield J, Johnson JP. Molecular Pharmacology of Selective Na V1.6 and Dual Na V1.6/Na V1.2 Channel Inhibitors that Suppress Excitatory Neuronal Activity Ex Vivo. ACS Chem Neurosci 2024; 15:1169-1184. [PMID: 38359277 PMCID: PMC10958515 DOI: 10.1021/acschemneuro.3c00757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/25/2024] [Accepted: 01/30/2024] [Indexed: 02/17/2024] Open
Abstract
Voltage-gated sodium channel (NaV) inhibitors are used to treat neurological disorders of hyperexcitability such as epilepsy. These drugs act by attenuating neuronal action potential firing to reduce excitability in the brain. However, all currently available NaV-targeting antiseizure medications nonselectively inhibit the brain channels NaV1.1, NaV1.2, and NaV1.6, which potentially limits the efficacy and therapeutic safety margins of these drugs. Here, we report on XPC-7724 and XPC-5462, which represent a new class of small molecule NaV-targeting compounds. These compounds specifically target inhibition of the NaV1.6 and NaV1.2 channels, which are abundantly expressed in excitatory pyramidal neurons. They have a > 100-fold molecular selectivity against NaV1.1 channels, which are predominantly expressed in inhibitory neurons. Sparing NaV1.1 preserves the inhibitory activity in the brain. These compounds bind to and stabilize the inactivated state of the channels thereby reducing the activity of excitatory neurons. They have higher potency, with longer residency times and slower off-rates, than the clinically used antiseizure medications carbamazepine and phenytoin. The neuronal selectivity of these compounds is demonstrated in brain slices by inhibition of firing in cortical excitatory pyramidal neurons, without impacting fast spiking inhibitory interneurons. XPC-5462 also suppresses epileptiform activity in an ex vivo brain slice seizure model, whereas XPC-7224 does not, suggesting a possible requirement of Nav1.2 inhibition in 0-Mg2+- or 4-AP-induced brain slice seizure models. The profiles of these compounds will facilitate pharmacological dissection of the physiological roles of NaV1.2 and NaV1.6 in neurons and help define the role of specific channels in disease states. This unique selectivity profile provides a new approach to potentially treat disorders of neuronal hyperexcitability by selectively downregulating excitatory circuits.
Collapse
Affiliation(s)
- Samuel J. Goodchild
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Noah Gregory Shuart
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Aaron D. Williams
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Wenlei Ye
- Neurocrine
Biosciences, San Diego, California 92130, United States
| | - R. Ryley Parrish
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Maegan Soriano
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Samrat Thouta
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Janette Mezeyova
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Matthew Waldbrook
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Richard Dean
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Thilo Focken
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - Mohammad-Reza Ghovanloo
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
- Department
of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Department
of Neurology, Yale University, New Haven, Connecticut 06519, United States
| | - Peter C. Ruben
- Department
of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Fiona Scott
- Neurocrine
Biosciences, San Diego, California 92130, United States
| | - Charles J. Cohen
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - James Empfield
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| | - JP Johnson
- Department
of Cellular and Molecular Biology, Xenon
Pharmaceuticals, Burnaby, BC V5G 4W8, Canada
| |
Collapse
|
7
|
Lin Y, Tao E, Champion JP, Corry B. A binding site for phosphoinositides described by multiscale simulations explains their modulation of voltage-gated sodium channels. eLife 2024; 12:RP91218. [PMID: 38465747 DOI: 10.7554/elife.91218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024] Open
Abstract
Voltage-gated sodium channels (Naᵥ) are membrane proteins which open to facilitate the inward flux of sodium ions into excitable cells. In response to stimuli, Naᵥ channels transition from the resting, closed state to an open, conductive state, before rapidly inactivating. Dysregulation of this functional cycle due to mutations causes diseases including epilepsy, pain conditions, and cardiac disorders, making Naᵥ channels a significant pharmacological target. Phosphoinositides are important lipid cofactors for ion channel function. The phosphoinositide PI(4,5)P2 decreases Naᵥ1.4 activity by increasing the difficulty of channel opening, accelerating fast inactivation and slowing recovery from fast inactivation. Using multiscale molecular dynamics simulations, we show that PI(4,5)P2 binds stably to inactivated Naᵥ at a conserved site within the DIV S4-S5 linker, which couples the voltage-sensing domain (VSD) to the pore. As the Naᵥ C-terminal domain is proposed to also bind here during recovery from inactivation, we hypothesize that PI(4,5)P2 prolongs inactivation by competitively binding to this site. In atomistic simulations, PI(4,5)P2 reduces the mobility of both the DIV S4-S5 linker and the DIII-IV linker, responsible for fast inactivation, slowing the conformational changes required for the channel to recover to the resting state. We further show that in a resting state Naᵥ model, phosphoinositides bind to VSD gating charges, which may anchor them and impede VSD activation. Our results provide a mechanism by which phosphoinositides alter the voltage dependence of activation and the rate of recovery from inactivation, an important step for the development of novel therapies to treat Naᵥ-related diseases.
Collapse
Affiliation(s)
- Yiechang Lin
- Research School of Biology, Australian National University, Canberra, Australia
| | - Elaine Tao
- Research School of Biology, Australian National University, Canberra, Australia
| | - James P Champion
- Research School of Biology, Australian National University, Canberra, Australia
| | - Ben Corry
- Research School of Biology, Australian National University, Canberra, Australia
| |
Collapse
|
8
|
Wang C, Derderian KD, Hamada E, Zhou X, Nelson AD, Kyoung H, Ahituv N, Bouvier G, Bender KJ. Impaired cerebellar plasticity hypersensitizes sensory reflexes in SCN2A-associated ASD. Neuron 2024:S0896-6273(24)00055-2. [PMID: 38412857 DOI: 10.1016/j.neuron.2024.01.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 01/03/2024] [Accepted: 01/29/2024] [Indexed: 02/29/2024]
Abstract
Children diagnosed with autism spectrum disorder (ASD) commonly present with sensory hypersensitivity or abnormally strong reactions to sensory stimuli. Such hypersensitivity can be overwhelming, causing high levels of distress that contribute markedly to the negative aspects of the disorder. Here, we identify a mechanism that underlies hypersensitivity in a sensorimotor reflex found to be altered in humans and in mice with loss of function in the ASD risk-factor gene SCN2A. The cerebellum-dependent vestibulo-ocular reflex (VOR), which helps maintain one's gaze during movement, was hypersensitized due to deficits in cerebellar synaptic plasticity. Heterozygous loss of SCN2A-encoded NaV1.2 sodium channels in granule cells impaired high-frequency transmission to Purkinje cells and long-term potentiation, a form of synaptic plasticity important for modulating VOR gain. VOR plasticity could be rescued in mice via a CRISPR-activator approach that increases Scn2a expression, demonstrating that evaluation of a simple reflex can be used to assess and quantify successful therapeutic intervention.
Collapse
Affiliation(s)
- Chenyu Wang
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA; Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Kimberly D Derderian
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Elizabeth Hamada
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Xujia Zhou
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Andrew D Nelson
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA; Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Henry Kyoung
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Nadav Ahituv
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA; Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Guy Bouvier
- Department of Physiology, University of California, San Francisco, San Francisco, CA, USA; Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay, 91400 Saclay, France.
| | - Kevin J Bender
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA; Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.
| |
Collapse
|
9
|
Tang HC, Zhou YR, Zuo JF, Wang YX, Piñero JC, Peng X, Chen MH. Voltage-gated sodium channel gene mutation and P450 gene expression are associated with the resistance of Aphis spiraecola Patch (Hemiptera: Aphididae) to lambda-cyhalothrin. Bull Entomol Res 2024; 114:49-56. [PMID: 38180110 DOI: 10.1017/s0007485323000603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Aphis spiraecola Patch is one of the most economically important tree fruit pests worldwide. The pyrethroid insecticide lambda-cyhalothrin is commonly used to control A. spiraecola. In this 2-year study, we quantified the resistance level of A. spiraecola to lambda-cyhalothrin in different regions of the Shaanxi province, China. The results showed that A. spiraecola had reached extremely high resistance levels with a 174-fold resistance ratio (RR) found in the Xunyi region. In addition, we compared the enzymatic activity and expression level of P450 genes among eight A. spiraecola populations. The P450 activity of A. spiraecola was significantly increased in five regions (Xunyi, Liquan, Fengxiang, Luochuan, and Xinping) compared to susceptible strain (SS). The expression levels of CYP6CY7, CYP6CY14, CYP6CY22, P4504C1-like, P4506a13, CYP4CZ1, CYP380C47, and CYP4CJ2 genes were significantly increased under lambda-cyhalothrin treatment and in the resistant field populations. A L1014F mutation in the sodium channel gene was found and the mutation rate was positively correlated with the LC50 of lambda-cyhalothrin. In conclusion, the levels of lambda-cyhalothrin resistance of A. spiraecola field populations were associated with P450s and L1014F mutations. Our combined findings provide evidence on the resistance mechanism of A. spiraecola to lambda-cyhalothrin and give a theoretical basis for rational and effective control of this pest species.
Collapse
Affiliation(s)
- Hong-Cheng Tang
- Department of Entomology, National Key Laboratory of Crop Improvement for Stress Tolerance and Production, Key Laboratory of Crop Pest Integrated Pest Management on the Loess Plateau of Ministry of Agriculture and Rural Affairs, Key Lab Plant Protect Resources and Pest Management of Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yu-Rong Zhou
- Department of Entomology, National Key Laboratory of Crop Improvement for Stress Tolerance and Production, Key Laboratory of Crop Pest Integrated Pest Management on the Loess Plateau of Ministry of Agriculture and Rural Affairs, Key Lab Plant Protect Resources and Pest Management of Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Jun-Feng Zuo
- Department of Entomology, National Key Laboratory of Crop Improvement for Stress Tolerance and Production, Key Laboratory of Crop Pest Integrated Pest Management on the Loess Plateau of Ministry of Agriculture and Rural Affairs, Key Lab Plant Protect Resources and Pest Management of Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yi-Xuan Wang
- Department of Entomology, National Key Laboratory of Crop Improvement for Stress Tolerance and Production, Key Laboratory of Crop Pest Integrated Pest Management on the Loess Plateau of Ministry of Agriculture and Rural Affairs, Key Lab Plant Protect Resources and Pest Management of Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Jaime C Piñero
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003 USA
| | - Xiong Peng
- Department of Entomology, National Key Laboratory of Crop Improvement for Stress Tolerance and Production, Key Laboratory of Crop Pest Integrated Pest Management on the Loess Plateau of Ministry of Agriculture and Rural Affairs, Key Lab Plant Protect Resources and Pest Management of Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Mao-Hua Chen
- Department of Entomology, National Key Laboratory of Crop Improvement for Stress Tolerance and Production, Key Laboratory of Crop Pest Integrated Pest Management on the Loess Plateau of Ministry of Agriculture and Rural Affairs, Key Lab Plant Protect Resources and Pest Management of Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling 712100, Shaanxi, China
| |
Collapse
|
10
|
Brown CO, Uy JA, Murtaza N, Rosa E, Alfonso A, Dave BM, Kilpatrick S, Cheng AA, White SH, Scherer SW, Singh KK. Disruption of the autism-associated gene SCN2A alters synaptic development and neuronal signaling in patient iPSC-glutamatergic neurons. Front Cell Neurosci 2024; 17:1239069. [PMID: 38293651 PMCID: PMC10824931 DOI: 10.3389/fncel.2023.1239069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 12/14/2023] [Indexed: 02/01/2024] Open
Abstract
SCN2A is an autism spectrum disorder (ASD) risk gene and encodes a voltage-gated sodium channel. However, the impact of ASD-associated SCN2A de novo variants on human neuron development is unknown. We studied SCN2A using isogenic SCN2A-/- induced pluripotent stem cells (iPSCs), and patient-derived iPSCs harboring a de novo R607* truncating variant. We used Neurogenin2 to generate excitatory (glutamatergic) neurons and found that SCN2A+/R607* and SCN2A-/- neurons displayed a reduction in synapse formation and excitatory synaptic activity. We found differential impact on actional potential dynamics and neuronal excitability that reveals a loss-of-function effect of the R607* variant. Our study reveals that a de novo truncating SCN2A variant impairs the development of human neuronal function.
Collapse
Affiliation(s)
- Chad O. Brown
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Jarryll A. Uy
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Nadeem Murtaza
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Elyse Rosa
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Alexandria Alfonso
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Biren M. Dave
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- SickKids Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | - Savannah Kilpatrick
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Annie A. Cheng
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Sean H. White
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Stephen W. Scherer
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- SickKids Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
| | - Karun K. Singh
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
11
|
Moreira-Junior L, Leal-Cardoso JH, Cassola AC, Carvalho-de-Souza JL. State-Dependent Blockade of Dorsal Root Ganglion Voltage-Gated Na + Channels by Anethole. Int J Mol Sci 2024; 25:1034. [PMID: 38256108 PMCID: PMC10816912 DOI: 10.3390/ijms25021034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/09/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Anethole is a phenolic compound synthesized by many aromatic plants. Anethole is a substance that humans can safely consume and has been studied for years as a biologically active molecule to treat a variety of conditions, including nerve damage, gastritis, inflammation, and nociception. Anethole is thought to carry out its biological activities through direct interaction with ion channels. Anethole is beneficial for neurodegenerative Alzheimer's and Parkinson's diseases. Nevertheless, nothing has been investigated regarding the effects of anethole on voltage-gated Na+ channels (VGSCs), which are major players in neuronal function. We used cultured dorsal root ganglion neurons from neonatal rats as a source of natively expressed VGSCs for electrophysiological studies using the whole-cell patch-clamp technique. Our data show that anethole interacts directly with VGSCs. Anethole quickly blocks and unblocks (when removed) voltage-activated Na+ currents in this preparation in a fully reversible manner. Anethole's binding affinity to these channels increases when the inactive states of these channels are populated, similar to lidocaine's effect on the same channels. Our data show that anethole inhibits neuronal activity by blocking VGSCs in a state-dependent manner. These findings relate to the putative anesthetic activity attributable to anethole, in addition to its potential benefit in neurodegenerative diseases.
Collapse
Affiliation(s)
| | - Jose Henrique Leal-Cardoso
- Superior Institute of Biomedical Sciences, State University of Ceará, Campus of Itaperi, Fortaleza 607402, CE, Brazil
| | - Antonio Carlos Cassola
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of Sao Paulo, São Paulo 05508, SP, Brazil
| | - Joao Luis Carvalho-de-Souza
- Department of Anesthesiology, University of Arizona, Tucson, AZ 85724, USA;
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of Sao Paulo, São Paulo 05508, SP, Brazil
| |
Collapse
|
12
|
Chang L, Ran Y, Yang M, Auferkorte O, Butz E, Hüser L, Haverkamp S, Euler T, Schubert T. Spike desensitisation as a mechanism for high-contrast selectivity in retinal ganglion cells. Front Cell Neurosci 2024; 17:1337768. [PMID: 38269116 PMCID: PMC10806099 DOI: 10.3389/fncel.2023.1337768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 12/19/2023] [Indexed: 01/26/2024] Open
Abstract
In the vertebrate retina, several dozens of parallel channels relay information about the visual world to the brain. These channels are represented by the different types of retinal ganglion cells (RGCs), whose responses are rendered selective for distinct sets of visual features by various mechanisms. These mechanisms can be roughly grouped into synaptic interactions and cell-intrinsic mechanisms, with the latter including dendritic morphology as well as ion channel complement and distribution. Here, we investigate how strongly ion channel complement can shape RGC output by comparing two mouse RGC types, the well-described ON alpha cell and a little-studied ON cell that is EGFP-labelled in the Igfbp5 mouse line and displays an unusual selectivity for stimuli with high contrast. Using patch-clamp recordings and computational modelling, we show that a higher activation threshold and a pronounced slow inactivation of the voltage-gated Na+ channels contribute to the distinct contrast tuning and transient responses in ON Igfbp5 RGCs, respectively. In contrast, such a mechanism could not be observed in ON alpha cells. This study provides an example for the powerful role that the last stage of retinal processing can play in shaping RGC responses.
Collapse
Affiliation(s)
- Le Chang
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Key Laboratory of Primate Neurobiology, Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Yanli Ran
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Mingpo Yang
- Key Laboratory of Primate Neurobiology, Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | | | - Elisabeth Butz
- Max-Planck-Institute for Brain Research, Frankfurt am Main, Germany
| | - Laura Hüser
- Max-Planck-Institute for Brain Research, Frankfurt am Main, Germany
| | - Silke Haverkamp
- Max-Planck-Institute for Brain Research, Frankfurt am Main, Germany
- Department of Computational Neuroethology, Max Planck Institute for Neurobiology of Behavior – Caesar, Bonn, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
| | - Timm Schubert
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
| |
Collapse
|
13
|
Deschênes I, Biswas R, Chinthalapudi K. Advances in understanding of cardiac sodium channel structure/function and their relation to disease pathogenesis and treatment. Heart Rhythm 2024; 21:124-125. [PMID: 38176766 PMCID: PMC10783539 DOI: 10.1016/j.hrthm.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 11/06/2023] [Indexed: 01/06/2024]
Affiliation(s)
- Isabelle Deschênes
- Physiology and Cell Biology Department, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio.
| | - Rupam Biswas
- Physiology and Cell Biology Department, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| | - Krishna Chinthalapudi
- Physiology and Cell Biology Department, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio
| |
Collapse
|
14
|
Kasai S, Ogawa N, Takagi M, Takahashi Y, Makino K, Arita H, Takahashi H, Yoshizawa K. Fentanyl Analogs Exert Antinociceptive Effects via Sodium Channel Blockade in Mice. Biol Pharm Bull 2024; 47:872-877. [PMID: 38658360 DOI: 10.1248/bpb.b24-00048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The formalin test is one approach to studying acute pain in rodents. Similar to formalin, injection with glutamate and veratrine can also produce a nociceptive response. This study investigated whether opioid-related compounds could suppress glutamate- and veratrine-induced nociceptive responses in mice at the same dose. The administration of morphine (3 mg/kg), hydromorphone (0.4 mg/kg), or fentanyl (0.03 mg/kg) suppressed glutamate-induced nociceptive response, but not veratrine-induced nociceptive response at the same doses. However, high doses of morphine (10 mg/kg), hydromorphone (2 mg/kg), or fentanyl (0.1 mg/kg) produced a significant reduction in the veratrine-induced nociceptive response. These results indicate that high doses are required when using morphine, hydromorphone, or fentanyl for sodium channel-related neuropathic pain, such as ectopic activity. As a result, concerns have arisen about overdose and abuse if the dose of opioids is steadily increased to relieve pain. In contrast, trimebutine (100 mg/kg) and fentanyl analog isobutyrylfentanyl (iBF; 0.1 mg/kg) suppressed both glutamate- and veratrine-induced nociceptive response. Furthermore, nor-isobutyrylfentanyl (nor-iBF; 1 mg/kg), which is a metabolite of iBF, suppressed veratrine-induced nociceptive response. Besides, the optimal antinociceptive dose of iBF, unlike fentanyl, only slightly increased locomotor activity and did not slow gastrointestinal transit. Cancer pain is a complex condition driven by inflammatory, neuropathic, and cancer-specific mechanisms. Thus, iBF may have the potential to be a superior analgesic than fentanyl.
Collapse
Affiliation(s)
- Satoka Kasai
- Laboratory of Pharmacology and Therapeutics, Department of Pharmacy, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| | - Natsuki Ogawa
- Laboratory of Pharmacology and Therapeutics, Department of Pharmacy, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| | - Miho Takagi
- Laboratory of Pharmacology and Therapeutics, Department of Pharmacy, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| | - Yukino Takahashi
- Laboratory of Pharmacology and Therapeutics, Department of Pharmacy, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| | - Kosho Makino
- Research Institute of Pharmaceutical Sciences, Musashino University
- Laboratory of Medicinal Chemistry, Department of Pharmacy, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| | - Hironobu Arita
- Laboratory of Medicinal Chemistry, Department of Pharmacy, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| | - Hideyo Takahashi
- Laboratory of Medicinal Chemistry, Department of Pharmacy, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| | - Kazumi Yoshizawa
- Laboratory of Pharmacology and Therapeutics, Department of Pharmacy, Faculty of Pharmaceutical Sciences, Tokyo University of Science
| |
Collapse
|
15
|
Lima AT, Britto-Júnior J, Moraes MO, Moraes MEA, Fregonesi A, Monica FZ, Antunes E, De Nucci G. 6-Nitrodopamine is an endogenous mediator of the rabbit corpus cavernosum relaxation. Andrology 2023. [PMID: 38156727 DOI: 10.1111/andr.13585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 12/03/2023] [Accepted: 12/18/2023] [Indexed: 01/03/2024]
Abstract
BACKGROUND 6-Nitrodopamine (6-ND) is a novel endogenous catecholamine that has a potent relaxant action on vascular smooth muscle in vitro. OBJECTIVES To evaluate the basal release of 6-ND and noradrenaline from rabbit-isolated corpus cavernosum (RbCC) and its relaxing action on this tissue. METHODS Rabbit corpus cavernosa were dissected and suspended in a 5-mL organ bath containing oxygenated Krebs-Henseleit's solution. 6-ND and noradrenaline release was quantified by liquid chromatography coupled to tandem mass spectrometry. The relaxant activity of 6-ND was assessed in RbCC strips pre-contracted with endothelin-1 (10 nM). RESULTS Rabbit corpus cavernosum presented basal release of both 6-ND (2.9 ± 0.8 ng/mL, n = 12) and noradrenaline (1.7 ± 1.3 ng/mL, n = 12). The 6-ND release was reduced by pre-treatment with Nω -nitro-l-arginine methyl ester (l-NAME) (100 µM), whereas that of noradrenaline was unaffected. Tetrodotoxin (TTX, 1 µM) abolished the noradrenaline release but had no effect on 6-ND release, indicating a non-neurogenic origin for 6-ND. 6-ND and the selective dopamine D2 -agonist L-741,626 caused concentration-dependent RbCC relaxations (pEC50 of 11 ± 0.15 and 11.15 ± 0.28, respectively). Pre-treatment with either l-NAME or the soluble guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-on (ODQ) (100 µM) caused a rightward shift of the concentration-response curve to 6-ND, without affecting the L-741,626 responses. In TTX (100 nM)-pre-treated preparations, neither l-NAME nor ODQ shifted the 6-ND concentration-response curve. Dopamine, noradrenaline, and adrenaline caused concentration-dependent RbCC contractions. Pre-incubation with 6-ND concentration-dependently inhibited the dopamine-induced contractions, without affecting those induced by either noradrenaline or adrenaline. DISCUSSION AND CONCLUSION 6-Nitrodopamine is the most potent endogenous relaxant agent in RbCC ever described and represents a novel mechanism by which NO causes corpus cavernosum smooth muscle relaxation. The finding that 6-ND acts as a truly selective dopamine D2 -receptor antagonist indicates that the balance of dopamine and 6-ND release/synthesis may be the main mechanism that modulates corpus cavernosum smooth muscle tonus in vivo.
Collapse
Affiliation(s)
- Antonio Tiago Lima
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas, Brazil
| | - José Britto-Júnior
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Manoel Odorico Moraes
- Clinical Pharmacology Unit, Drug Research and Development Center, Federal University of Ceará (UFC), Fortaleza, Brazil
| | - Maria Elisabete A Moraes
- Clinical Pharmacology Unit, Drug Research and Development Center, Federal University of Ceará (UFC), Fortaleza, Brazil
| | - Adriano Fregonesi
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Fabíola Z Monica
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Edson Antunes
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Gilberto De Nucci
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas, Brazil
- Clinical Pharmacology Unit, Drug Research and Development Center, Federal University of Ceará (UFC), Fortaleza, Brazil
- Department of Pharmacology, Institute of Biomedical Sciences (ICB), University of São Paulo (USP), São Paulo, Brazil
| |
Collapse
|
16
|
Fang H, Hu W, Kang Q, Kuang X, Wang L, Zhang X, Liao H, Yang L, Yang H, Jiang Z, Wu L. Clinical characteristics and genetic analysis of pediatric patients with sodium channel gene mutation-related childhood epilepsy: a review of 94 patients. Front Neurol 2023; 14:1310419. [PMID: 38174099 PMCID: PMC10764033 DOI: 10.3389/fneur.2023.1310419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/27/2023] [Indexed: 01/05/2024] Open
Abstract
Objective This study aimed to examine the clinical and gene-mutation characteristics of pediatric patients with sodium channel gene mutation-related childhood epilepsy and to provide a basis for precision treatment and genetic counseling. Methods The clinical data from 94 patients with sodium channel gene mutation-related childhood epilepsy who were treated at Hunan Children's Hospital from August 2012 to December 2022 were retrospectively evaluated, and the clinical characteristics, gene variants, treatment, and follow-up status were analyzed and summarized. Results Our 94 pediatric patients with sodium channel gene variant-related childhood epilepsy comprised 37 girls and 57 boys. The age of disease onset ranged from 1 day to 3 years. We observed seven different sodium channel gene variants, and 55, 14, 9, 6, 6, 2, and 2 patients had SCNlA, SCN2A, SCN8A, SCN9A, SCN1B, SCN11A, and SCN3A variants, respectively. We noted that 52 were reported variants and 42 were novel variants. Among all gene types, SCN1A, SCN2A, and SCN8A variants were associated with an earlier disease onset age. With the exception of the SCN1B, the other six genes were associated with clustering seizures. Except for variants SCN3A and SCN11A, some patients with other variants had status epilepticus (SE). The main diagnosis of children with SCN1A variants was Dravet syndrome (DS) (72.7%), whereas patients with SCN2A and SCN8A variants were mainly diagnosed with various types of epileptic encephalopathy, accounting for 85.7% (12 of 14) and 88.9% (8 of 9) respectively. A total of five cases of sudden unexpected death in epilepsy (SUDEP) occurred in patients with SCN1A, SCN2A, and SCN8A variants. The proportion of benign epilepsy in patients with SCN9A, SCN11A, and SCN1B variants was relatively high, and the epilepsy control rate was higher than the rate of other variant types. Conclusion Sodium channel gene variants involve different epileptic syndromes, and the treatment responses also vary. We herein reported 42 novel variants, and we are also the first ever to report two patients with SCN11A variants, thereby increasing the gene spectrum and phenotypic profile of sodium channel dysfunction. We provide a basis for precision treatment and prognostic assessment.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Liwen Wu
- Neurology Department, Hunan Children's Hospital, Changsha, China
| |
Collapse
|
17
|
Chen L, Wang Y, Zhang K, Wu S. Functional diversity of sodium channel variants in common eastern bumblebee, Bombus impatiens. Arch Insect Biochem Physiol 2023; 114:e22052. [PMID: 37672296 DOI: 10.1002/arch.22052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/05/2023] [Accepted: 08/16/2023] [Indexed: 09/07/2023]
Abstract
For the past decade, Colony Collapse Disorder has been reported worldwide. Insecticides containing pyrethroids may be responsible for a decline in bees, which are more sensitive to pyrethroids compared with other insects. Voltage-gated sodium channels (Nav ) are the major target sites of pyrethroids, and the sodium channel diversity is generated through extensive alternative splicing and RNA editing. In this study, we cloned and analyzed the function of variants of the Nav channel, BiNav , from Bombus impatiens. BiNav covers a 46 kb genome region including 30 exons. Sequence analysis of 56 clones showed that the clones can be grouped into 22 splice types with 11 optional exons (exons j, w, p, q, r, b, e, t, l/k, and z). Here, a special alternative exon w is identified, encoding a stretch of 31 amino acid resides in domain I between S3 and S4. RNA editing generates 18 amino acid changes in different positions in individual variants. Among 56 variants examined, only six variants generated sufficient sodium currents for functional characterization in Xenopus oocytes. In the presence of B. impatiens TipE and TEH1, the sodium current amplitude of BiNav 1-1 increased by fourfold, while TipE of other insect species had no effect on the expression. Abundant alternative splicing and RNA editing of BiNav suggests the molecular and functional pharmacology diversity of the Nav channel for bumblebees. This study provides a theoretical basis for the design of insecticides that specifically target pests without affecting beneficial insects.
Collapse
Affiliation(s)
- Longwei Chen
- College of Breeding and Multiplication, Hainan University, Sanya, China
- School of Tropical Agriculture and Forestry, Hainan University, Danzhou, China
| | - Yuquan Wang
- College of Breeding and Multiplication, Hainan University, Sanya, China
- School of Tropical Agriculture and Forestry, Hainan University, Danzhou, China
| | - Kun Zhang
- College of Breeding and Multiplication, Hainan University, Sanya, China
- School of Tropical Agriculture and Forestry, Hainan University, Danzhou, China
| | - Shaoying Wu
- College of Breeding and Multiplication, Hainan University, Sanya, China
- School of Tropical Agriculture and Forestry, Hainan University, Danzhou, China
| |
Collapse
|
18
|
Abstract
Voltage-gated sodium channels initiate action potentials in nerve and muscle, and voltage-gated calcium channels couple depolarization of the plasma membrane to intracellular events such as secretion, contraction, synaptic transmission, and gene expression. In this Review and Perspective article, I summarize early work that led to identification, purification, functional reconstitution, and determination of the amino acid sequence of the protein subunits of sodium and calcium channels and showed that their pore-forming subunits are closely related. Decades of study by antibody mapping, site-directed mutagenesis, and electrophysiological recording led to detailed two-dimensional structure-function maps of the amino acid residues involved in voltage-dependent activation and inactivation, ion permeation and selectivity, and pharmacological modulation. Most recently, high-resolution three-dimensional structure determination by X-ray crystallography and cryogenic electron microscopy has revealed the structural basis for sodium and calcium channel function and pharmacological modulation at the atomic level. These studies now define the chemical basis for electrical signaling and provide templates for future development of new therapeutic agents for a range of neurological and cardiovascular diseases.
Collapse
|
19
|
Wada Y. From Basic Cardiac Electrophysiology to Mechanism-Based Therapy in Ion Channelopathies. JACC Clin Electrophysiol 2023; 9:2491-2493. [PMID: 38151300 DOI: 10.1016/j.jacep.2023.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/04/2023] [Accepted: 11/04/2023] [Indexed: 12/29/2023]
Affiliation(s)
- Yuko Wada
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
| |
Collapse
|
20
|
Finkelstein DS, Du Bois J. Trifunctional Saxitoxin Conjugates for Covalent Labeling of Voltage-Gated Sodium Channels. Chembiochem 2023; 24:e202300493. [PMID: 37746898 PMCID: PMC10863845 DOI: 10.1002/cbic.202300493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/24/2023] [Indexed: 09/26/2023]
Abstract
Voltage-gated sodium ion channels (NaV s) are integral membrane protein complexes responsible for electrical signal conduction in excitable cells. Methods that enable selective labeling of NaV s hold potential value for understanding how channel regulation and post-translational modification are influenced during development and in response to diseases and disorders of the nervous system. We have developed chemical reagents patterned after (+)-saxitoxin (STX) - a potent and reversible inhibitor of multiple NaV isoforms - and affixed with a reactive electrophile and either a biotin cofactor, fluorophore, or 'click' functional group for labeling wild-type channels. Our studies reveal enigmatic structural effects of the probes on the potency and efficiency of covalent protein modification. Among the compounds analyzed, a STX-maleimide-coumarin derivative is most effective at irreversibly blocking Na+ conductance when applied to recombinant NaV s and endogenous channels expressed in hippocampal neurons. Mechanistic analysis supports the conclusion that high-affinity toxin binding is a prerequisite for covalent protein modification. Results from these studies are guiding the development of next-generation tool compounds for selective modification of NaV s expressed in the plasma membranes of cells.
Collapse
Affiliation(s)
- Darren S Finkelstein
- Department of Chemistry, Stanford University, 337 Campus Dr., Stanford, CA 94305, USA
- Present address: Pliant Therapeutics, 260 Littlefield Avenue, South San Francisco, CA 94080, USA
| | - J Du Bois
- Department of Chemistry, Stanford University, 337 Campus Dr., Stanford, CA 94305, USA
| |
Collapse
|
21
|
Chen C, Ziobro J, Robinson-Cooper L, Hodges SL, Chen Y, Edokobi N, Lopez-Santiago L, Habig K, Moore C, Minton J, Bramson S, Scheuing C, Daddo N, Štěrbová K, Weckhuysen S, Parent JM, Isom LL. Epilepsy and sudden unexpected death in epilepsy in a mouse model of human SCN1B-linked developmental and epileptic encephalopathy. Brain Commun 2023; 5:fcad283. [PMID: 38425576 PMCID: PMC10903178 DOI: 10.1093/braincomms/fcad283] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/13/2023] [Accepted: 10/18/2023] [Indexed: 03/02/2024] Open
Abstract
Voltage-gated sodium channel β1 subunits are essential proteins that regulate excitability. They modulate sodium and potassium currents, function as cell adhesion molecules and regulate gene transcription following regulated intramembrane proteolysis. Biallelic pathogenic variants in SCN1B, encoding β1, are linked to developmental and epileptic encephalopathy 52, with clinical features overlapping Dravet syndrome. A recessive variant, SCN1B-c.265C>T, predicting SCN1B-p.R89C, was homozygous in two children of a non-consanguineous family. One child was diagnosed with Dravet syndrome, while the other had a milder phenotype. We identified an unrelated biallelic SCN1B-c.265C>T patient with a clinically more severe phenotype than Dravet syndrome. We used CRISPR/Cas9 to knock-in SCN1B-p.R89C to the mouse Scn1b locus (Scn1bR89/C89). We then rederived the line on the C57BL/6J background to allow comparisons between Scn1bR89/R89 and Scn1bC89/C89 littermates with Scn1b+/+ and Scn1b-/- mice, which are congenic on C57BL/6J, to determine whether the SCN1B-c.265C>T variant results in loss-of-function. Scn1bC89/C89 mice have normal body weights and ∼20% premature mortality, compared with severely reduced body weight and 100% mortality in Scn1b-/- mice. β1-p.R89C polypeptides are expressed in brain at comparable levels to wild type. In heterologous cells, β1-p.R89C localizes to the plasma membrane and undergoes regulated intramembrane proteolysis similar to wild type. Heterologous expression of β1-p.R89C results in sodium channel α subunit subtype specific effects on sodium current. mRNA abundance of Scn2a, Scn3a, Scn5a and Scn1b was increased in Scn1bC89/C89 somatosensory cortex, with no changes in Scn1a. In contrast, Scn1b-/- mouse somatosensory cortex is haploinsufficient for Scn1a, suggesting an additive mechanism for the severity of the null model via disrupted regulation of another Dravet syndrome gene. Scn1bC89/C89 mice are more susceptible to hyperthermia-induced seizures at post-natal Day 15 compared with Scn1bR89/R89 littermates. EEG recordings detected epileptic discharges in young adult Scn1bC89/C89 mice that coincided with convulsive seizures and myoclonic jerks. We compared seizure frequency and duration in a subset of adult Scn1bC89/C89 mice that had been exposed to hyperthermia at post-natal Day 15 versus a subset that were not hyperthermia exposed. No differences in spontaneous seizures were detected between groups. For both groups, the spontaneous seizure pattern was diurnal, occurring with higher frequency during the dark cycle. This work suggests that the SCN1B-c.265C>T variant does not result in complete loss-of-function. Scn1bC89/C89 mice more accurately model SCN1B-linked variants with incomplete loss-of-function compared with Scn1b-/- mice, which model complete loss-of-function, and thus add to our understanding of disease mechanisms as well as our ability to develop new therapeutic strategies.
Collapse
Affiliation(s)
- Chunling Chen
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Julie Ziobro
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | | | - Samantha L Hodges
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yan Chen
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Nnamdi Edokobi
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Luis Lopez-Santiago
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Karl Habig
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Chloe Moore
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Joe Minton
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Sabrina Bramson
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Caroline Scheuing
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Noor Daddo
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Katalin Štěrbová
- Department of Pediatric Neurology, Charles University and Motol Hospital, V Úvalu 84, 150 06 Prague 5, Czech Republic
| | - Sarah Weckhuysen
- Applied & Translational Neurogenomics Group, VIB Center for Molecular Neurology, VIB, Universiteitsplein 1 B-2610 Antwerpen, Belgium
- Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Universiteitsplein 1 B-2610 Antwerpen, Belgium
- Department of Neurology, Antwerp University Hospital, Universiteitsplein 1B-2610 Antwerpen, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Universiteitsplein 1B-2610 Antwerpen, Belgium
| | - Jack M Parent
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Michigan Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Neurology, VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
| | - Lori L Isom
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| |
Collapse
|
22
|
Hill SF, Jafar-Nejad P, Rigo F, Meisler MH. Reduction of Kcnt1 is therapeutic in mouse models of SCN1A and SCN8A epilepsy. Front Neurosci 2023; 17:1282201. [PMID: 37901435 PMCID: PMC10603267 DOI: 10.3389/fnins.2023.1282201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 09/25/2023] [Indexed: 10/31/2023] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are severe seizure disorders with inadequate treatment options. Gain- or loss-of-function mutations of neuronal ion channel genes, including potassium channels and voltage-gated sodium channels, are common causes of DEE. We previously demonstrated that reduced expression of the sodium channel gene Scn8a is therapeutic in mouse models of sodium and potassium channel mutations. In the current study, we tested whether reducing expression of the potassium channel gene Kcnt1 would be therapeutic in mice with mutation of the sodium channel genes Scn1a or Scn8a. A Kcnt1 antisense oligonucleotide (ASO) prolonged survival of both Scn1a and Scn8a mutant mice, suggesting a modulatory effect for KCNT1 on the balance between excitation and inhibition. The cation channel blocker quinidine was not effective in prolonging survival of the Scn8a mutant. Our results implicate KCNT1 as a therapeutic target for treatment of SCN1A and SCN8A epilepsy.
Collapse
Affiliation(s)
- Sophie F. Hill
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States
| | | | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA, United States
| | - Miriam H. Meisler
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, United States
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| |
Collapse
|
23
|
Frosio A, Micaglio E, Polsinelli I, Calamaio S, Melgari D, Prevostini R, Ghiroldi A, Binda A, Carrera P, Villa M, Mastrocinque F, Presi S, Salerno R, Boccellino A, Anastasia L, Ciconte G, Ricagno S, Pappone C, Rivolta I. Unravelling Novel SCN5A Mutations Linked to Brugada Syndrome: Functional, Structural, and Genetic Insights. Int J Mol Sci 2023; 24:15089. [PMID: 37894777 PMCID: PMC10606416 DOI: 10.3390/ijms242015089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/08/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023] Open
Abstract
Brugada Syndrome (BrS) is a rare inherited cardiac arrhythmia causing potentially fatal ventricular tachycardia or fibrillation, mainly occurring during rest or sleep in young individuals without heart structural issues. It increases the risk of sudden cardiac death, and its characteristic feature is an abnormal ST segment elevation on the ECG. While BrS has diverse genetic origins, a subset of cases can be conducted to mutations in the SCN5A gene, which encodes for the Nav1.5 sodium channel. Our study focused on three novel SCN5A mutations (p.A344S, p.N347K, and p.D349N) found in unrelated BrS families. Using patch clamp experiments, we found that these mutations disrupted sodium currents: p.A344S reduced current density, while p.N347K and p.D349N completely abolished it, leading to altered voltage dependence and inactivation kinetics when co-expressed with normal channels. We also explored the effects of mexiletine treatment, which can modulate ion channel function. Interestingly, the p.N347K and p.D349N mutations responded well to the treatment, rescuing the current density, while p.A344S showed a limited response. Structural analysis revealed these mutations were positioned in key regions of the channel, impacting its stability and function. This research deepens our understanding of BrS by uncovering the complex relationship between genetic mutations, ion channel behavior, and potential therapeutic interventions.
Collapse
Affiliation(s)
- Anthony Frosio
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
| | - Emanuele Micaglio
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (F.M.); (A.B.)
| | - Ivan Polsinelli
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
| | - Serena Calamaio
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
| | - Dario Melgari
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
| | - Rachele Prevostini
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
| | - Andrea Ghiroldi
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
- Laboratory of Stem Cells for Tissue Engineering, IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy
| | - Anna Binda
- School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore, 48, 20900 Monza, Italy;
| | - Paola Carrera
- Laboratory of Clinical Molecular Genetics and Cytogenetics, Unit of Genomics for Diagnosis of Human Diseases, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy; (P.C.); (S.P.)
| | - Marco Villa
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
| | - Flavio Mastrocinque
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (F.M.); (A.B.)
| | - Silvia Presi
- Laboratory of Clinical Molecular Genetics and Cytogenetics, Unit of Genomics for Diagnosis of Human Diseases, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy; (P.C.); (S.P.)
| | - Raffaele Salerno
- Faculty of Medicine and Surgery, Vita-Salute San Raffaele University, Via Olgettina, 58, 20132 Milan, Italy;
| | - Antonio Boccellino
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (F.M.); (A.B.)
| | - Luigi Anastasia
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
- Laboratory of Stem Cells for Tissue Engineering, IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy
- Faculty of Medicine and Surgery, Vita-Salute San Raffaele University, Via Olgettina, 58, 20132 Milan, Italy;
| | - Giuseppe Ciconte
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (F.M.); (A.B.)
- Faculty of Medicine and Surgery, Vita-Salute San Raffaele University, Via Olgettina, 58, 20132 Milan, Italy;
| | - Stefano Ricagno
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
- Department of Biosciences, Università degli Studi di Milano, Via Celoria, 26, 20133 Milan, Italy
| | - Carlo Pappone
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (F.M.); (A.B.)
- Faculty of Medicine and Surgery, Vita-Salute San Raffaele University, Via Olgettina, 58, 20132 Milan, Italy;
| | - Ilaria Rivolta
- Institute of Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy; (A.F.); (E.M.); (I.P.); (S.C.); (D.M.); (R.P.); (A.G.); (M.V.); (L.A.); (G.C.); (S.R.); (C.P.)
- School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore, 48, 20900 Monza, Italy;
| |
Collapse
|
24
|
Frara N, Barbe MF, Giaddui D, Porreca DS, Braverman AS, Tiwari E, Ahmad A, Brown JM, Johnston BR, Bazarek SF, Ruggieri MR. Nerve transfer for restoration of lower motor neuron-lesioned bladder, urethral, and anal sphincter function in a dog model. Part 3. nicotinic receptor characterization. Am J Physiol Regul Integr Comp Physiol 2023; 325:R344-R358. [PMID: 37458380 PMCID: PMC10642361 DOI: 10.1152/ajpregu.00273.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 06/09/2023] [Accepted: 07/05/2023] [Indexed: 09/05/2023]
Abstract
Very little is known about the physiological role of nicotinic receptors in canine bladders, although functional nicotinic receptors have been reported in bladders of many species. Utilizing in vitro methods, we evaluated nicotinic receptors mediating bladder function in dogs: control (9 female and 11 male normal controls, 5 sham operated), Decentralized (9 females, decentralized 6-21 mo), and obturator-to-pelvic nerve transfer reinnervated (ObNT-Reinn; 9 females; decentralized 9-13 mo, then reinnervated with 8-12 mo recovery). Muscle strips were collected, mucosa-denuded, and mounted in muscle baths before incubation with neurotransmitter antagonists, and contractions to the nicotinic receptor agonist epibatidine were determined. Strip response to epibatidine, expressed as percent potassium chloride, was similar (∼35% in controls, 30% in Decentralized, and 24% in ObNT-Reinn). Differentially, epibatidine responses in Decentralized and ObNT-Reinn bladder strips were lower than controls after tetrodotoxin (TTX, a sodium channel blocker that inhibits axonal action potentials). Yet, in all groups, epibatidine-induced strip contractions were similarly inhibited by mecamylamine and hexamethonium (ganglionic nicotinic receptor antagonists), SR 16584 (α3β4 neuronal nicotinic receptor antagonist), atracurium and tubocurarine (neuromuscular nicotinic receptor antagonists), and atropine (muscarinic receptor antagonist), indicating that nicotinic receptors (particularly α3β4 subtypes), neuromuscular and muscarinic receptors play roles in bladder contractility. In control bladder strips, since tetrodotoxin did not inhibit epibatidine contractions, nicotinic receptors are likely located on nerve terminals. The tetrodotoxin inhibition of epibatidine-induced contractions in Decentralized and ObNT-Reinn suggests a relocation of nicotinic receptors from nerve terminals to more distant axonal sites, perhaps as a compensatory mechanism to recover bladder function.
Collapse
Affiliation(s)
- Nagat Frara
- Center for Translational Medicine at the Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, United States
| | - Mary F Barbe
- Center for Translational Medicine at the Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, United States
| | - Dania Giaddui
- Center for Translational Medicine at the Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, United States
| | - Danielle S Porreca
- Department of Neurology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, United States
| | - Alan S Braverman
- Center for Translational Medicine at the Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, United States
| | - Ekta Tiwari
- School of Engineering, Brown University, Providence, Rhode Island, United States
| | - Attia Ahmad
- Cooper Medical School of Rowan University, Camden, New Jersey, United States
| | - Justin M Brown
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts, United States
| | - Benjamin R Johnston
- Department of Neurosurgery, Brigham & Women's Hospital, Boston, Massachusetts, United States
| | - Stanley F Bazarek
- Department of Neurosurgery, Brigham & Women's Hospital, Boston, Massachusetts, United States
| | - Michael R Ruggieri
- Center for Translational Medicine at the Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, United States
- Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts, United States
| |
Collapse
|
25
|
Hussein RA, Ahmed M, Heinemann SH. Selenomethionine mis-incorporation and redox-dependent voltage-gated sodium channel gain of function. J Neurochem 2023; 167:262-276. [PMID: 37679952 DOI: 10.1111/jnc.15957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/09/2023]
Abstract
Selenomethionine (SeMet) readily replaces methionine (Met) residues in proteins during translation. Long-term dietary SeMet intake results in the accumulation of the amino acid in tissue proteins. Despite the high rates of SeMet incorporation in proteins and its stronger susceptibility to oxidation compared to Met, little is known about the effect of SeMet mis-incorporation on electrical excitability and ion channels. Fast inactivation of voltage-gated sodium (NaV ) channels is essential for exact action potential shaping with even minute impairment of inactivation resulting in a plethora of adverse phenotypes. Met oxidation of the NaV channel inactivation motif (Ile-Phe-Met) and further Met residues causes a marked loss of inactivation. Here, we examined the impact of SeMet mis-incorporation on the function of NaV channels. While extensive SeMet incorporation into recombinant rat NaV 1.4 channels preserved their normal function, it greatly sensitized the channels to mild oxidative stress, resulting in loss of inactivation and diminished maximal current, both reversible by dithiothreitol-induced reduction. SeMet incorporation similarly affected human NaV 1.4, NaV 1.2, NaV 1.5, and NaV 1.7. In mouse dorsal root ganglia (DRG) neurons, 1 day of SeMet exposure exacerbated the oxidation-mediated broadening of action potentials. SeMet-treated DRGs also exhibited a stronger increase in the persistent NaV current in response to oxidation. SeMet incorporation in NaV proteins coinciding with oxidative insults may therefore result in hyperexcitability pathologies, such as cardiac arrhythmias and neuropathies, like congenital NaV channel gain-of-function mutations.
Collapse
Affiliation(s)
- Rama A Hussein
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, Jena, Germany
| | - Marwa Ahmed
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, Jena, Germany
| | - Stefan H Heinemann
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, Jena, Germany
| |
Collapse
|
26
|
Minard AY, Clark CJ, Ahern CA, Piper RC. Beta-subunit-eliminated eHAP expression (BeHAPe) cells reveal subunit regulation of the cardiac voltage-gated sodium channel. J Biol Chem 2023; 299:105132. [PMID: 37544648 PMCID: PMC10506104 DOI: 10.1016/j.jbc.2023.105132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023] Open
Abstract
Voltage-gated sodium (NaV) channels drive the upstroke of the action potential and are comprised of a pore-forming α-subunit and regulatory β-subunits. The β-subunits modulate the gating, trafficking, and pharmacology of the α-subunit. These functions are routinely assessed by ectopic expression in heterologous cells. However, currently available expression systems may not capture the full range of these effects since they contain endogenous β-subunits. To better reveal β-subunit functions, we engineered a human cell line devoid of endogenous NaV β-subunits and their immediate phylogenetic relatives. This new cell line, β-subunit-eliminated eHAP expression (BeHAPe) cells, were derived from haploid eHAP cells by engineering inactivating mutations in the β-subunits SCN1B, SCN2B, SCN3B, and SCN4B, and other subfamily members MPZ (myelin protein zero(P0)), MPZL1, MPZL2, MPZL3, and JAML. In diploid BeHAPe cells, the cardiac NaV α-subunit, NaV1.5, was highly sensitive to β-subunit modulation and revealed that each β-subunit and even MPZ imparted unique gating properties. Furthermore, combining β1 and β2 with NaV1.5 generated a sodium channel with hybrid properties, distinct from the effects of the individual subunits. Thus, this approach revealed an expanded ability of β-subunits to regulate NaV1.5 activity and can be used to improve the characterization of other α/β NaV complexes.
Collapse
Affiliation(s)
- Annabel Y Minard
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States
| | - Colin J Clark
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States.
| | - Robert C Piper
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa, United States.
| |
Collapse
|
27
|
Bouzroud W, Tazzite A, Boussakri I, Gazzaz B, Dehbi H. A novel SCN8A variant of unknown significance in pediatric epilepsy: a case report. J Int Med Res 2023; 51:3000605231187931. [PMID: 37498161 PMCID: PMC10387795 DOI: 10.1177/03000605231187931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023] Open
Abstract
Variants in SCN8A are associated with several diseases, including developmental and epileptic encephalopathy, intermediate epilepsy or mild-to-moderate developmental and epileptic encephalopathy, self-limited familial infantile epilepsy, neurodevelopmental delays with generalized epilepsy, neurodevelopmental disorder without epilepsy, hypotonia, and movement disorders. Herein, we report an 8-year-old Moroccan boy with intermediate epilepsy of unknown origin, intellectual disability, autism spectrum disorder, and hyperactivity. The patient presented a normal 46, XY karyotype and a normal comparative genomic hybridization profile. Whole-exome sequencing was performed, and heterozygous variants were identified in KCNK4 and SCN8A. The SCN8A variant [c.4499C > T (p.Pro1500Leu)] was also detected in the healthy mother and was classified as a variant of uncertain clinical significance. This variant occurs in a highly conserved domain, which may affect the function of the encoded protein. More studies are needed to confirm the pathogenicity of this novel variant to establish the effective care, management, and genetic counselling of affected individuals.
Collapse
Affiliation(s)
- Wafaa Bouzroud
- Medical Genetics Laboratory, Ibn Rochd University Hospital, Casablanca, Morocco
| | - Amal Tazzite
- Laboratory of Cellular and Molecular Pathology, Faculty of Medicine and Pharmacy, Hassan II University of Casablanca, Casablanca, Morocco
| | - Ikhlass Boussakri
- Laboratory of Cellular and Molecular Pathology, Faculty of Medicine and Pharmacy, Hassan II University of Casablanca, Casablanca, Morocco
| | - Bouchaïb Gazzaz
- Laboratory of Cellular and Molecular Pathology, Faculty of Medicine and Pharmacy, Hassan II University of Casablanca, Casablanca, Morocco
- Genetics Analysis Institute, Royal Gendarmerie, Rabat, Morocco
| | - Hind Dehbi
- Medical Genetics Laboratory, Ibn Rochd University Hospital, Casablanca, Morocco
- Laboratory of Cellular and Molecular Pathology, Faculty of Medicine and Pharmacy, Hassan II University of Casablanca, Casablanca, Morocco
| |
Collapse
|
28
|
Chen AY, Brooks BR, Damjanovic A. Ion channel selectivity through ion-modulated changes of selectivity filter p Ka values. Proc Natl Acad Sci U S A 2023; 120:e2220343120. [PMID: 37339196 PMCID: PMC10293820 DOI: 10.1073/pnas.2220343120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 04/26/2023] [Indexed: 06/22/2023] Open
Abstract
In bacterial voltage-gated sodium channels, the passage of ions through the pore is controlled by a selectivity filter (SF) composed of four glutamate residues. The mechanism of selectivity has been the subject of intense research, with suggested mechanisms based on steric effects, and ion-triggered conformational change. Here, we propose an alternative mechanism based on ion-triggered shifts in pKa values of SF glutamates. We study the NavMs channel for which the open channel structure is available. Our free-energy calculations based on molecular dynamics simulations suggest that pKa values of the four glutamates are higher in solution of K+ ions than in solution of Na+ ions. Higher pKa in the presence of K+ stems primarily from the higher population of dunked conformations of the protonated Glu sidechain, which exhibit a higher pKa shift. Since pKa values are close to the physiological pH, this results in predominant population of the fully deprotonated state of glutamates in Na+ solution, while protonated states are predominantly populated in K+ solution. Through molecular dynamics simulations we calculate that the deprotonated state is the most conductive, the singly protonated state is less conductive, and the doubly protonated state has significantly reduced conductance. Thus, we propose that a significant component of selectivity is achieved through ion-triggered shifts in the protonation state, which favors more conductive states for Na+ ions and less conductive states for K+ ions. This mechanism also suggests a strong pH dependence of selectivity, which has been experimentally observed in structurally similar NaChBac channels.
Collapse
Affiliation(s)
- Ada Y. Chen
- Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD21218
- Laboratory of Computational Biology, National Heart, Lung and Blood Institute, NIH, Bethesda, MD20892
| | - Bernard R. Brooks
- Laboratory of Computational Biology, National Heart, Lung and Blood Institute, NIH, Bethesda, MD20892
| | - Ana Damjanovic
- Laboratory of Computational Biology, National Heart, Lung and Blood Institute, NIH, Bethesda, MD20892
- Department of Biophysics, Johns Hopkins University, Baltimore, MD21218
| |
Collapse
|
29
|
Marra C, Hartke TV, Ringkamp M, Goldfarb M. Enhanced sodium channel inactivation by temperature and FHF2 deficiency blocks heat nociception. Pain 2023; 164:1321-1331. [PMID: 36607284 PMCID: PMC10166761 DOI: 10.1097/j.pain.0000000000002822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 10/13/2022] [Accepted: 10/31/2022] [Indexed: 01/07/2023]
Abstract
ABSTRACT Transient voltage-gated sodium currents are essential for the initiation and conduction of action potentials in neurons and cardiomyocytes. The amplitude and duration of sodium currents are tuned by intracellular fibroblast growth factor homologous factors (FHFs/iFGFs) that associate with the cytoplasmic tails of voltage-gated sodium channels (Na v s), and genetic ablation of Fhf genes disturbs neurological and cardiac functions. Among reported phenotypes, Fhf2null mice undergo lethal hyperthermia-induced cardiac conduction block attributable to the combined effects of FHF2 deficiency and elevated temperature on the cardiac sodium channel (Na v 1.5) inactivation rate. Fhf2null mice also display a lack of heat nociception, while retaining other somatosensory capabilities. Here, we use electrophysiological and computational methods to show that the heat nociception deficit can be explained by the combined effects of elevated temperature and FHF2 deficiency on the fast inactivation gating of Na v 1.7 and tetrodotoxin-resistant sodium channels expressed in dorsal root ganglion C fibers. Hence, neurological and cardiac heat-associated deficits in Fhf2null mice derive from shared impacts of FHF deficiency and temperature towards Na v inactivation gating kinetics in distinct tissues.
Collapse
Affiliation(s)
- Christopher Marra
- Department of Biological Sciences, Hunter College of City University, New York, NY, United States
- Program in Biology, Graduate Center of City University, New York, NY, United States
| | - Timothy V. Hartke
- Department of Neurosurgery, Neurosurgery Pain Research Institute, Johns Hopkins University, Baltimore, MD, United States
| | - Matthias Ringkamp
- Department of Neurosurgery, Neurosurgery Pain Research Institute, Johns Hopkins University, Baltimore, MD, United States
| | - Mitchell Goldfarb
- Department of Biological Sciences, Hunter College of City University, New York, NY, United States
- Program in Biology, Graduate Center of City University, New York, NY, United States
| |
Collapse
|
30
|
Leynse AK, Mudge EM, Turner AD, Maskrey BH, Robertson A. Gambierone and Sodium Channel Specific Bioactivity Are Associated with the Extracellular Metabolite Pool of the Marine Dinoflagellate Coolia palmyrensis. Mar Drugs 2023; 21:md21040244. [PMID: 37103383 PMCID: PMC10143066 DOI: 10.3390/md21040244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 04/04/2023] [Accepted: 04/11/2023] [Indexed: 04/28/2023] Open
Abstract
Tropical epibenthic dinoflagellate communities produce a plethora of bioactive secondary metabolites, including the toxins ciguatoxins (CTXs) and potentially gambierones, that can contaminate fishes, leading to ciguatera poisoning (CP) when consumed by humans. Many studies have assessed the cellular toxicity of causative dinoflagellate species to better understand the dynamics of CP outbreaks. However, few studies have explored extracellular toxin pools which may also enter the food web, including through alternative and unanticipated routes of exposure. Additionally, the extracellular exhibition of toxins would suggest an ecological function and may prove important to the ecology of the CP-associated dinoflagellate species. In this study, semi-purified extracts obtained from the media of a Coolia palmyrensis strain (DISL57) isolated from the U.S. Virgin Islands were assessed for bioactivity via a sodium channel specific mouse neuroblastoma cell viability assay and associated metabolites evaluated by targeted and non-targeted liquid chromatography tandem and high-resolution mass spectrometry. We found that extracts of C. palmyrensis media exhibit both veratrine enhancing bioactivity and non-specific bioactivity. LC-HR-MS analysis of the same extract fractions identified gambierone and multiple undescribed peaks with mass spectral characteristics suggestive of structural similarities to polyether compounds. These findings implicate C. palmyrensis as a potential contributor to CP and highlight extracellular toxin pools as a potentially significant source of toxins that may enter the food web through multiple exposure pathways.
Collapse
Affiliation(s)
- Alexander K Leynse
- School of Marine & Environmental Sciences, University of South Alabama, 600 Clinic Drive, Mobile, AL 36688, USA
- Dauphin Island Sea Lab, 101 Bienville Boulevard, Dauphin Island, AL 36528, USA
| | - Elizabeth M Mudge
- National Research Council of Canada, 1411 Oxford Street, Halifax, NS B3M3Z1, Canada
| | - Andrew D Turner
- Center for the Environment, Fisheries, and Aquaculture Science, Barrack Road, Weymouth DT4 8UB, UK
| | - Benjamin H Maskrey
- Center for the Environment, Fisheries, and Aquaculture Science, Barrack Road, Weymouth DT4 8UB, UK
| | - Alison Robertson
- School of Marine & Environmental Sciences, University of South Alabama, 600 Clinic Drive, Mobile, AL 36688, USA
- Dauphin Island Sea Lab, 101 Bienville Boulevard, Dauphin Island, AL 36528, USA
| |
Collapse
|
31
|
Nguyen E, Tétreault M, Toffa DH, Cossette P, Samarut É, Nguyen DK. Novel NALCN variant linked to temporal lobe epilepsy. Am J Med Genet A 2023. [PMID: 37046053 DOI: 10.1002/ajmg.a.63209] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 02/14/2023] [Accepted: 03/31/2023] [Indexed: 04/14/2023]
Abstract
The sodium leak channel (NALCN) gene encodes a sodium leak channel that plays an important role in the regulation of the resting membrane potential and the control of neuronal excitability. Mutations in the NALCN gene have been reported in patients with infantile hypotonia with psychomotor retardation and characteristic facies (IHPRF) and congenital contractures of the limbs and face with hypotonia and developmental delay (CLIFAHDD syndrome). We describe the case of a father with drug-resistant left temporo-orbitofrontal epilepsy and his son with mildly-symptomatic temporal epilepsy (only recurrent déjà vu auras) whose genetic panels identified a likely pathogenic deletion of exon 27 on the NALCN gene. Our study helps broaden the clinical spectrum of diseases associated with mutations in the NALCN gene.
Collapse
Affiliation(s)
- Emmanuelle Nguyen
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Martine Tétreault
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
- Department of Neuroscience, Université de Montréal, Montreal, Quebec, Canada
| | - Dènahin Hinnoutondji Toffa
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
- Department of Neuroscience, Université de Montréal, Montreal, Quebec, Canada
| | - Patrick Cossette
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
- Department of Neuroscience, Université de Montréal, Montreal, Quebec, Canada
- Neurology Division, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, Quebec, Canada
| | - Éric Samarut
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
- Department of Neuroscience, Université de Montréal, Montreal, Quebec, Canada
| | - Dang Khoa Nguyen
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
- Department of Neuroscience, Université de Montréal, Montreal, Quebec, Canada
- Neurology Division, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, Quebec, Canada
| |
Collapse
|
32
|
Wisedchaisri G, Gamal El-Din TM, Zheng N, Catterall WA. Structural basis for severe pain caused by mutations in the S4-S5 linkers of voltage-gated sodium channel Na V1.7. Proc Natl Acad Sci U S A 2023; 120:e2219624120. [PMID: 36996107 PMCID: PMC10083536 DOI: 10.1073/pnas.2219624120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/24/2023] [Indexed: 03/31/2023] Open
Abstract
Gain-of-function mutations in voltage-gated sodium channel NaV1.7 cause severe inherited pain syndromes, including inherited erythromelalgia (IEM). The structural basis of these disease mutations, however, remains elusive. Here, we focused on three mutations that all substitute threonine residues in the alpha-helical S4-S5 intracellular linker that connects the voltage sensor to the pore: NaV1.7/I234T, NaV1.7/I848T, and NaV1.7/S241T in order of their positions in the amino acid sequence within the S4-S5 linkers. Introduction of these IEM mutations into the ancestral bacterial sodium channel NaVAb recapitulated the pathogenic gain-of-function of these mutants by inducing a negative shift in the voltage dependence of activation and slowing the kinetics of inactivation. Remarkably, our structural analysis reveals a common mechanism of action among the three mutations, in which the mutant threonine residues create new hydrogen bonds between the S4-S5 linker and the pore-lining S5 or S6 segment in the pore module. Because the S4-S5 linkers couple voltage sensor movements to pore opening, these newly formed hydrogen bonds would stabilize the activated state substantially and thereby promote the 8 to 18 mV negative shift in the voltage dependence of activation that is characteristic of the NaV1.7 IEM mutants. Our results provide key structural insights into how IEM mutations in the S4-S5 linkers may cause hyperexcitability of NaV1.7 and lead to severe pain in this debilitating disease.
Collapse
Affiliation(s)
| | | | - Ning Zheng
- Department of Pharmacology, University of Washington, Seattle, WA98195
- HHMI, University of Washington, Seattle, WA98195
| | | |
Collapse
|
33
|
Smith BJ, McHugh CF, Hirano AA, Brecha NC, Barnes S. Transient and Sustained Ganglion Cell Light Responses Are Differentially Modulated by Intrinsically Produced Reactive Oxygen Species Acting upon Specific Voltage-Gated Na + Channel Isoforms. J Neurosci 2023; 43:2291-2304. [PMID: 36828637 PMCID: PMC10072295 DOI: 10.1523/jneurosci.1723-22.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/26/2023] Open
Abstract
Increasing spike rates drive greater neuronal energy demand. In turn, mitochondrial ATP production leads to the generation of reactive oxygen species (ROS) that can modulate ion channel gating. Does ROS production autoregulate the excitability of a neuron? We investigated the links between retinal ganglion cell (RGC) excitability and spike activity-driven ROS production in male and female mice. Changes to the light-evoked and current-evoked spike patterns of functionally identified αRGC subtypes, along with their NaV channel-gating properties, were recorded during experimentally induced decreases and increases of intracellular ROS. During periods of highest spike rates (e.g., following light onset in ON sustained RGCs and light offset in OFF sustained RGCs), these αRGC subtypes responded to reductions of ROS (induced by catalase or glutathione monoethyl ester) with higher spike rates. Increases in ROS (induced by mercaptosuccinate, antimycin-A, or H2O2) lowered spike rates. In ON and OFF transient RGCs, there were no changes in spike rate during ROS decreases but increased ROS increased spiking. This suggests that endogenous ROS are intrinsic neuromodulators in RGCs having high metabolic demands but not in RGCs with lower energy needs. We identified ROS-induced shifts in the voltage-dependent gating of specific isoforms of NaV channels that account for the modulation of ON and OFF sustained RGC spike frequency by ROS-mediated feedback. ROS-induced changes to NaV channel gating, affecting activation and inactivation kinetics, are consistent with the differing spike pattern alterations observed in RGC subtypes. Cell-autonomous generation of ROS during spiking contributes to tuning the spike patterns of RGCs.SIGNIFICANCE STATEMENT Energy production within retinal ganglion cells (RGCs) is accompanied by metabolic by-products harmful to cellular function. How these by-products modulate the excitability of RGCs bears heavily on visual function and the etiology of optic neuropathies. A novel hypothesis of how RGC metabolism can produce automodulation of electrical signaling was tested by identifying the characteristics and biophysical origins of changes to the excitability of RGCs caused by oxidizing by-products in the retina. This impacts our understanding of the pathophysiology of RGC dysfunction, supporting an emerging model in which increases in oxidizing chemical species during energy production, but not necessarily bioenergetic failure, lead to preferential degeneration of specific subtypes of RGCs, yielding loss of different aspects of visual capacity.
Collapse
Affiliation(s)
- Benjamin J Smith
- Doheny Eye Institute, University of California, Los Angeles, California 91103
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
| | - Cyrus F McHugh
- Doheny Eye Institute, University of California, Los Angeles, California 91103
| | - Arlene A Hirano
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
| | - Nicholas C Brecha
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
- Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
- Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, California 90073
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
- Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
| | - Steven Barnes
- Doheny Eye Institute, University of California, Los Angeles, California 91103
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
- Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
| |
Collapse
|
34
|
Mendes LC, Viana GMM, Nencioni ALA, Pimenta DC, Beraldo-Neto E. Scorpion Peptides and Ion Channels: An Insightful Review of Mechanisms and Drug Development. Toxins (Basel) 2023; 15:238. [PMID: 37104176 PMCID: PMC10145618 DOI: 10.3390/toxins15040238] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 04/28/2023] Open
Abstract
The Buthidae family of scorpions consists of arthropods with significant medical relevance, as their venom contains a diverse range of biomolecules, including neurotoxins that selectively target ion channels in cell membranes. These ion channels play a crucial role in regulating physiological processes, and any disturbance in their activity can result in channelopathies, which can lead to various diseases such as autoimmune, cardiovascular, immunological, neurological, and neoplastic conditions. Given the importance of ion channels, scorpion peptides represent a valuable resource for developing drugs with targeted specificity for these channels. This review provides a comprehensive overview of the structure and classification of ion channels, the action of scorpion toxins on these channels, and potential avenues for future research. Overall, this review highlights the significance of scorpion venom as a promising source for discovering novel drugs with therapeutic potential for treating channelopathies.
Collapse
Affiliation(s)
- Lais Campelo Mendes
- Programa de Pós-Graduação em Ciências—Toxinologia do Instituto Butantan, São Paulo 05503-900, Brazil
- Laboratório de Bioquímica do Instituto Butantan, São Paulo 05503-900, Brazil
| | | | | | | | - Emidio Beraldo-Neto
- Laboratório de Bioquímica do Instituto Butantan, São Paulo 05503-900, Brazil
| |
Collapse
|
35
|
Strege PR, Cowan LM, Alcaino C, Mazzone A, Ahern CA, Milescu LS, Farrugia G, Beyder A. Mechanosensitive pore opening of a prokaryotic voltage-gated sodium channel. eLife 2023; 12:79271. [PMID: 36912788 PMCID: PMC10038658 DOI: 10.7554/elife.79271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 03/10/2023] [Indexed: 03/14/2023] Open
Abstract
Voltage-gated ion channels (VGICs) orchestrate electrical activities that drive mechanical functions in contractile tissues such as the heart and gut. In turn, contractions change membrane tension and impact ion channels. VGICs are mechanosensitive, but the mechanisms of mechanosensitivity remain poorly understood. Here, we leverage the relative simplicity of NaChBac, a prokaryotic voltage-gated sodium channel from Bacillus halodurans, to investigate mechanosensitivity. In whole-cell experiments on heterologously transfected HEK293 cells, shear stress reversibly altered the kinetic properties of NaChBac and increased its maximum current, comparably to the mechanosensitive eukaryotic sodium channel NaV1.5. In single-channel experiments, patch suction reversibly increased the open probability of a NaChBac mutant with inactivation removed. A simple kinetic mechanism featuring a mechanosensitive pore opening transition explained the overall response to force, whereas an alternative model with mechanosensitive voltage sensor activation diverged from the data. Structural analysis of NaChBac identified a large displacement of the hinged intracellular gate, and mutagenesis near the hinge diminished NaChBac mechanosensitivity, further supporting the proposed mechanism. Our results suggest that NaChBac is overall mechanosensitive due to the mechanosensitivity of a voltage-insensitive gating step associated with the pore opening. This mechanism may apply to eukaryotic VGICs, including NaV1.5.
Collapse
Affiliation(s)
- Peter R Strege
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States
| | - Luke M Cowan
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States
| | - Constanza Alcaino
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States
| | - Amelia Mazzone
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, United States
| | - Lorin S Milescu
- Department of Biology, University of Maryland, College Park, College Park, United States
| | - Gianrico Farrugia
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, United States
| | - Arthur Beyder
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, United States
| |
Collapse
|
36
|
Kim JS, Sun H, Meeker S, Undem BJ. Role of Na V 1.9 in inflammatory mediator-induced activation of mouse airway vagal C-fibres. J Physiol 2023; 601:1139-1150. [PMID: 36750759 PMCID: PMC10023385 DOI: 10.1113/jp283751] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 01/23/2023] [Indexed: 02/09/2023] Open
Abstract
The influence of NaV 1.9 on inflammatory mediator-induced activation of airway vagal nodose C-fibres was evaluated by comparing responses in wild-type versus NaV 1.9-/- mice. A single-cell RT-PCR analysis indicated that virtually all nodose C-fibre neurons expressed NaV 1.9 (SCN11A) mRNA. Using extracellular electrophysiological recordings in an isolated vagally innervated mouse trachea-lung preparation, it was noted that mediators acting via G protein-coupled receptors (PAR2), or ionotropic receptors (P2×3) were 70-85% less effective in evoking action potential discharge in the absence of NaV 1.9. However, there was no difference in action potential discharge between wild-type and NaV 1.9-/- when the stimulus was a rapid punctate mechanical stimulus. An analysis of the passive and active properties of isolated nodose neurons revealed no difference between neurons from wild-type and NaV 1.9-/- mice, with the exception of a modest difference in the duration of the afterhyperpolarization. There was also no difference in the amount of current required to evoke action potentials (rheobase) or the action potential voltage threshold. The inward current evoked by the chemical mediator by a P2×3 agonist was the same in wild-type versus NaV 1.9-/- neurons. However, the current was sufficient to evoke action potential only in the wild-type neurons. The data support the speculation that NaV 1.9 could be an attractive therapeutic target for inflammatory airway disease by selectively inhibiting inflammatory mediator-associated vagal C-fibre activation. KEY POINTS: Inflammatory mediators were much less effective in activating the terminals of vagal airway C-fibres in mice lacking NaV 1.9. The active and passive properties of nodose neurons were the same between wild-type neurons and NaV 1.9-/- neurons. Nerves lacking NaV 1.9 responded, normally, with action potential discharge to rapid punctate mechanical stimulation of the terminals or the rapid stimulation of the cell bodies with inward current injections. NaV 1.9 channels could be an attractive target to selectively inhibit vagal nociceptive C-fibre activation evoked by inflammatory mediators without blocking the nerves' responses to the potentially hazardous stimuli associated with aspiration.
Collapse
Affiliation(s)
- Joyce S Kim
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hui Sun
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sonya Meeker
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Bradley J Undem
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|
37
|
Thompson CH, Potet F, Abramova TV, DeKeyser JM, Ghabra NF, Vanoye CG, Millichap J, George AL. Epilepsy-associated SCN2A (Na V 1.2) Variants Exhibit Diverse and Complex Functional Properties. bioRxiv 2023:2023.02.23.529757. [PMID: 36865317 PMCID: PMC9980081 DOI: 10.1101/2023.02.23.529757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Pathogenic variants in neuronal voltage-gated sodium (Na V ) channel genes including SCN2A , which encodes Na V 1.2, are frequently discovered in neurodevelopmental disorders with and without epilepsy. SCN2A is also a high confidence risk gene for autism spectrum disorder (ASD) and nonsyndromic intellectual disability (ID). Previous work to determine the functional consequences of SCN2A variants yielded a paradigm in which predominantly gain-of-function (GoF) variants cause epilepsy whereas loss-of-function (LoF) variants are associated with ASD and ID. However, this framework is based on a limited number of functional studies conducted under heterogenous experimental conditions whereas most disease-associated SCN2A variants have not been functionally annotated. We determined the functional properties of more than 30 SCN2A variants using automated patch clamp recording to assess the analytical validity of this approach and to examine whether a binary classification of variant dysfunction is evident in a larger cohort studied under uniform conditions. We studied 28 disease-associated variants and 4 common population variants using two distinct alternatively spliced forms of Na V 1.2 that were heterologously expressed in HEK293T cells. Multiple biophysical parameters were assessed on 5,858 individual cells. We found that automated patch clamp recording provided a valid high throughput method to ascertain detailed functional properties of Na V 1.2 variants with concordant findings for a subset of variants that were previously studied using manual patch clamp. Additionally, many epilepsy-associated variants in our study exhibited complex patterns of gain- and loss-of-function properties that are difficult to classify overall by a simple binary scheme. The higher throughput achievable with automated patch clamp enables study of a larger number of variants, greater standardization of recording conditions, freedom from operator bias, and enhanced experimental rigor valuable for accurate assessment of Na V channel variant dysfunction. Together, this approach will enhance our ability to discern relationships between variant channel dysfunction and neurodevelopmental disorders.
Collapse
Affiliation(s)
- Christopher H Thompson
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Franck Potet
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Tatiana V Abramova
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Jean-Marc DeKeyser
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Nora F Ghabra
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Carlos G Vanoye
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - John Millichap
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 USA
| |
Collapse
|
38
|
Marchese-Rojas M, Islas ÁA, Mancilla-Simbro C, Millan-PerezPeña L, León JS, Salinas-Stefanon EM. Inhibition of the Human Neuronal Sodium Channel Na v1.9 by Arachidonyl-2-Chloroethylamide, An Analogue of Anandamide in a hNa v1.9/rNa v1.4 Chimera, An Experimental and in Silico Study. Neuroscience 2023; 511:39-52. [PMID: 36156289 DOI: 10.1016/j.neuroscience.2022.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/12/2022] [Accepted: 09/16/2022] [Indexed: 01/23/2023]
Abstract
Cannabinoids regulate analgesia, which has aroused much interest in identifying new pharmacological therapies in the management of refractory pain. Voltage-gated Na+ channels (Navs) play an important role in inflammatory and neuropathic pain. In particular, Nav1.9 is involved in nociception and the understanding of its pharmacology has lagged behind because it is difficult to express in heterologous systems. Here, we utilized the chimeric channel hNav1.9_C4, that comprises the extracellular and transmembrane domains of hNav1.9, co-expressed with the ß1 subunit on CHO-K1 cells to characterize the electrophysiological effects of ACEA, a synthetic surrogate of the endogenous cannabinoid anandamide. ACEA induced a tonic block, decelerated the fast inactivation, markedly shifted steady-state inactivation in the hyperpolarized direction, decreasing the window current and showed use-dependent block, with a high affinity for the inactivated state (ki = 0.84 µM). Thus, we argue that ACEA possess a local anaesthetic-like profile. To provide a mechanistic understanding of its mode of action at the molecular level, we combined induced fit docking with Monte Carlo simulations and electrostatic complementarity. In agreement with the experimental evidence, our computer simulations revealed that ACEA binds Tyr1599 of the local anaesthetics binding site of the hNav1.9, contacting residues that bind cannabinol (CBD) in the NavMs channel. ACEA adopted a conformation remarkably similar to the crystallographic conformation of anandamide on a non-homologous protein, obstructing the Na+ permeation pathway below the selectivity filter to occupy a highly conserved binding pocket at the intracellular side. These results describe a mechanism of action, possibly involved in cannabinoid analgesia.
Collapse
Affiliation(s)
- Mario Marchese-Rojas
- Laboratory of Biophysics, Institute of Physiology, Benemérita Universidad Autónoma de Puebla, Mexico
| | - Ángel A Islas
- Vicerrectoría de Investigación y Estudios de Posgrado, Benemérita Universidad Autónoma de Puebla, Mexico; Laboratory of Computational Molecular Simulations, Department of Pharmacy, Benemérita Universidad Autónoma de Puebla, Mexico.
| | - Claudia Mancilla-Simbro
- Laboratory of Biophysics, Institute of Physiology, Benemérita Universidad Autónoma de Puebla, Mexico
| | | | - Jorge S León
- Laboratory of Biophysics, Institute of Physiology, Benemérita Universidad Autónoma de Puebla, Mexico
| | | |
Collapse
|
39
|
Wang X, Zhang J, Yang Y, Wu Y. Equivalent intensity but differential dominance of sodium channel blocker insecticide resistance conferred by F1845Y and V1848I mutations of the voltage-gated sodium channel in Plutella xylostella. Insect Sci 2023; 30:125-134. [PMID: 35366363 DOI: 10.1111/1744-7917.13042] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/15/2022] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
Two point mutations (F1845Y and V1848I) in the voltage-gated sodium channel gene of Plutella xylostella are involved in the target-site resistance to sodium channel blocker insecticides (SCBIs). The contribution of the individual mutations to the SCBI resistance and the associated inheritance modes is as yet unclear. Through 2 rounds of single-pair crossing and marker-assisted selection, 2 P. xylostella strains (1845Y and 1848I) bearing homozygous F1845Y or V1848I mutant alleles were successfully established from a field-collected population, and the contribution of each mutation to SCBI resistance, as well as associated inheritance patterns, was determined. When compared with the susceptible SZPS strain, each of the mutations individually conferred equally high-level resistance to indoxacarb (378 and 313 fold) and metaflumizone (734 and 674 fold), respectively. However, dominance levels of resistance to SCBIs were significantly different between the 2 resistant strains. Resistance of the 1845Y strain to indoxacarb and metaflumizone was inherited as an autosomal and incompletely dominant trait (D values ranged from 0.43 to 0.76). In contrast, that of the 1848I strain followed an autosomal but incompletely recessive to semidominant mode (D values: -0.24 to 0.09). Our findings enriched the current understanding of inheritance and mechanisms of SCBI resistance in P. xylostella, and will help develop resistance management programs for P. xylostella and other economic pests.
Collapse
Affiliation(s)
- Xingliang Wang
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Jianheng Zhang
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Yihua Yang
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Yidong Wu
- Key Laboratory of Integrated Pest Management on Crops in East China (MARA), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| |
Collapse
|
40
|
Quiñonez M, DiFranco M, Wu F, Cannon SC. Retigabine suppresses loss of force in mouse models of hypokalaemic periodic paralysis. Brain 2023; 146:1554-1560. [PMID: 36718088 PMCID: PMC10115351 DOI: 10.1093/brain/awac441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 10/18/2022] [Accepted: 11/12/2022] [Indexed: 02/01/2023] Open
Abstract
Recurrent episodes of weakness in periodic paralysis are caused by intermittent loss of muscle fibre excitability, as a consequence of sustained depolarization of the resting potential. Repolarization is favoured by increasing the fibre permeability to potassium. Based on this principle, we tested the efficacy of retigabine, a potassium channel opener, to suppress the loss of force induced by a low-K+ challenge in hypokalaemic periodic paralysis (HypoPP). Retigabine can prevent the episodic loss of force in HypoPP. Knock-in mutant mouse models of HypoPP (Cacna1s p.R528H and Scn4a p.R669H) were used to determine whether pre-treatment with retigabine prevented the loss of force, or post-treatment hastened recovery of force for a low-K+ challenge in an ex vivo contraction assay. Retigabine completely prevents the loss of force induced by a 2 mM K+ challenge (protection) in our mouse models of HypoPP, with 50% inhibitory concentrations of 0.8 ± 0.13 μM and 2.2 ± 0.42 μM for NaV1.4-R669H and CaV1.1-R528H, respectively. In comparison, the effective concentration for the KATP channel opener pinacidil was 10-fold higher. Application of retigabine also reversed the loss of force (rescue) for HypoPP muscle maintained in 2 mM K+. Our findings show that retigabine, a selective agonist of the KV7 family of potassium channels, is effective for the prevention of low-K+ induced attacks of weakness and to enhance recovery from an ongoing loss of force in mouse models of type 1 (Cacna1s) and type 2 (Scn4a) HypoPP. Substantial protection from the loss of force occurred in the low micromolar range, well within the therapeutic window for retigabine.
Collapse
Affiliation(s)
- Marbella Quiñonez
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Marino DiFranco
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Fenfen Wu
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.,Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| |
Collapse
|
41
|
Gutierrez‐Quintana R, Christen M, Faller KME, Guevar J, Jagannathan V, Leeb T. SCN9A variant in a family of mixed breed dogs with congenital insensitivity to pain. J Vet Intern Med 2023; 37:230-235. [PMID: 36630088 PMCID: PMC9889608 DOI: 10.1111/jvim.16610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/08/2022] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Congenital insensitivity to pain (CIP) and hereditary sensory and autonomic neuropathies (HSANs) are a rare group of genetic disorders causing inability to feel pain. Three different associated variants have been identified in dogs: 1 in Border Collies, 1 in mixed breed dogs, and 1 in Spaniels and Pointers. OBJECTIVES To clinically and genetically characterize CIP in a family of mixed breed dogs. ANIMALS Two mixed breed dogs from the same litter were independently presented: 1 for evaluation of painless fractures, and the other for chronic thermal skin injuries. METHODS Physical, neurological, and histopathological evaluations were performed. Whole genome sequencing of 1 affected dog was used to identify homozygous protein-changing variants that were not present in 926 control genomes from diverse dog breeds. RESULTS Physical and neurological examinations showed the absence of superficial and deep pain perception in the entire body. Histopathological evaluations of the brain, spinal cord and sensory ganglia were normal. Whole genome sequencing identified a homozygous missense variant in SCN9A, XM_038584713.1:c.2761C>T or XP_038440641.1:(p.Arg921Cys). Both affected dogs were homozygous for the mutant allele, which was not detected in 926 dogs of different breeds. CONCLUSIONS AND CLINICAL IMPORTANCE We confirmed the diagnosis of CIP in a family of mixed breed dogs and identified a likely pathogenic variant in the SCN9A gene. The clinical signs observed in these dogs mimic those reported in humans with pathogenic SCN9A variants causing CIP. This report is the first of a spontaneous pathogenic SCN9A variant in domestic animals.
Collapse
Affiliation(s)
- Rodrigo Gutierrez‐Quintana
- Small Animal Hospital, School of Biodiversity, One Health and Veterinary MedicineUniversity of GlasgowGlasgowUK
| | - Matthias Christen
- Institute of Genetics, Vetsuisse FacultyUniversity of BernBernSwitzerland
| | - Kiterie M. E. Faller
- Royal (Dick) School of Veterinary StudiesThe University of EdinburghMidlothianUK
| | - Julien Guevar
- Department of Clinical Veterinary Sciences, Vetsuisse FacultyUniversity of BernBernSwitzerland
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse FacultyUniversity of BernBernSwitzerland
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse FacultyUniversity of BernBernSwitzerland
| |
Collapse
|
42
|
De Bellis M, Boccanegra B, Cerchiara AG, Imbrici P, De Luca A. Blockers of Skeletal Muscle Na v1.4 Channels: From Therapy of Myotonic Syndrome to Molecular Determinants of Pharmacological Action and Back. Int J Mol Sci 2023; 24:ijms24010857. [PMID: 36614292 PMCID: PMC9821513 DOI: 10.3390/ijms24010857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/28/2022] [Accepted: 12/30/2022] [Indexed: 01/05/2023] Open
Abstract
The voltage-gated sodium channels represent an important target for drug discovery since a large number of physiological processes are regulated by these channels. In several excitability disorders, including epilepsy, cardiac arrhythmias, chronic pain, and non-dystrophic myotonia, blockers of voltage-gated sodium channels are clinically used. Myotonia is a skeletal muscle condition characterized by the over-excitability of the sarcolemma, resulting in delayed relaxation after contraction and muscle stiffness. The therapeutic management of this disorder relies on mexiletine and other sodium channel blockers, which are not selective for the Nav1.4 skeletal muscle sodium channel isoform. Hence, the importance of deepening the knowledge of molecular requirements for developing more potent and use-dependent drugs acting on Nav1.4. Here, we review the available treatment options for non-dystrophic myotonia and the structure-activity relationship studies performed in our laboratory with a focus on new compounds with potential antimyotonic activity.
Collapse
|
43
|
Higerd-Rusli GP, Tyagi S, Liu S, Dib-Hajj FB, Waxman SG, Dib-Hajj SD. The fates of internalized Na V1.7 channels in sensory neurons: Retrograde cotransport with other ion channels, axon-specific recycling, and degradation. J Biol Chem 2023; 299:102816. [PMID: 36539035 PMCID: PMC9843449 DOI: 10.1016/j.jbc.2022.102816] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 12/05/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022] Open
Abstract
Neuronal function relies on the maintenance of appropriate levels of various ion channels at the cell membrane, which is accomplished by balancing secretory, degradative, and recycling pathways. Neuronal function further depends on membrane specialization through polarized distribution of specific proteins to distinct neuronal compartments such as axons. Voltage-gated sodium channel NaV1.7, a threshold channel for firing action potentials in nociceptors, plays a major role in human pain, and its abundance in the plasma membrane is tightly regulated. We have recently characterized the anterograde axonal trafficking of NaV1.7 channels in Rab6A-positive vesicles, but the fate of internalized channels is not known. Membrane proteins that have undergone endocytosis can be directed into multiple pathways including those for degradation, recycling to the membrane, and transcytosis. Here, we demonstrate NaV1.7 endocytosis and dynein-dependent retrograde trafficking in Rab7-containing late endosomes together with other axonal membrane proteins using real-time imaging of live neurons. We show that some internalized NaV1.7 channels are delivered to lysosomes within the cell body, and that there is no evidence for NaV1.7 transcytosis. In addition, we show that NaV1.7 is recycled specifically to the axonal membrane as opposed to the soma membrane, suggesting a novel mechanism for the development of neuronal polarity. Together, these results shed light on the mechanisms by which neurons maintain excitable membranes and may inform efforts to target ion channel trafficking for the treatment of disorders of excitability.
Collapse
Affiliation(s)
- Grant P Higerd-Rusli
- MD/PhD Program, Yale University School of Medicine, New Haven, Connecticut, USA; Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA
| | - Sidharth Tyagi
- MD/PhD Program, Yale University School of Medicine, New Haven, Connecticut, USA; Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA
| | - Shujun Liu
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA
| | - Fadia B Dib-Hajj
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA
| | - Stephen G Waxman
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA.
| | - Sulayman D Dib-Hajj
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA.
| |
Collapse
|
44
|
Andrews JG, Galindo MK, Hack JB, Watkins JC, Conecker GA, Hammer MF. The International SCN8A Patient Registry: A Scientific Resource to Advance the Understanding and Treatment of a Rare Pediatric Neurodevelopmental Syndrome. J Registry Manag 2023; 50:4-10. [PMID: 37577282 PMCID: PMC10414210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Genetic variants in the SCN8A gene underlie a wide spectrum of neurodevelopmental phenotypes that range from severe epileptic encephalopathy to benign familial infantile epilepsy to neurodevelopmental delays with or without seizures. A host of additional comorbidities also contribute to the phenotypic spectrum. As a result of the recent identification of the genetic etiology and the length of time it often takes to diagnose patients, little data are available on the natural history of these conditions. The International SCN8A Patient Registry was developed in 2015 to fill gaps in understanding the spectrum of the disease and its natural history, as well as the lived experiences of individuals with SCN8A syndrome. Another goal of the registry is to collect longitudinal data from participants on a regular basis. In this article, we describe the construction and structure of the International SCN8A Patient Registry, present the type of information available, and highlight particular analyses that demonstrate how registry data can provide insights into the clinical management of SCN8A syndrome.
Collapse
Affiliation(s)
| | | | - Joshua B. Hack
- University of Arizona, Tucson, Arizona
- BIO5 Institute, University of Arizona, Tucson, Arizona
| | | | | | - Michael F. Hammer
- University of Arizona, Tucson, Arizona
- BIO5 Institute, University of Arizona, Tucson, Arizona
- International SCN8A Alliance
| | | |
Collapse
|
45
|
Schenk JE, Gaudry Q. Nonspiking Interneurons in the Drosophila Antennal Lobe Exhibit Spatially Restricted Activity. eNeuro 2023; 10:ENEURO. [PMID: 36650069 DOI: 10.1523/ENEURO.0109-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 09/17/2022] [Accepted: 10/21/2022] [Indexed: 01/19/2023] Open
Abstract
Inhibitory interneurons are important for neuronal circuit function. They regulate sensory inputs and enhance output discriminability (Olsen and Wilson, 2008; Root et al., 2008; Olsen et al., 2010). Often, the identities of interneurons can be determined by location and morphology, which can have implications for their functions (Wachowiak and Shipley, 2006). While most interneurons fire traditional action potentials, many are nonspiking. These can be seen in insect olfaction (Laurent and Davidowitz, 1994; Husch et al., 2009; Tabuchi et al., 2015) and the vertebrate retina (Gleason et al., 1993). Here, we present the novel observation of nonspiking inhibitory interneurons in the antennal lobe (AL) of the adult fruit fly, Drosophila melanogaster These neurons have a morphology where they innervate a patchwork of glomeruli. We used electrophysiology to determine whether their nonspiking characteristic is because of a lack of sodium current. We then used immunohistochemsitry and in situ hybridization to show this is likely achieved through translational regulation of the voltage-gated sodium channel gene, para Using in vivo calcium imaging, we explored how these cells respond to odors, finding regional isolation in their responses' spatial patterns. Further, their response patterns were dependent on both odor identity and concentration. Thus, we surmise these neurons are electrotonically compartmentalized such that activation of the neurites in one region does not propagate across the whole antennal lobe. We propose these neurons may be the source of intraglomerular inhibition in the AL and may contribute to regulation of spontaneous activity within glomeruli.
Collapse
|
46
|
Shibano M, Kubota T, Kokubun N, Miyaji Y, Kuriki H, Ito Y, Hamanoue H, Takahashi MP. Periodic paralysis due to cumulative effects of rare variants in SCN4A with small functional alterations. Muscle Nerve 2022; 66:757-761. [PMID: 36116128 DOI: 10.1002/mus.27725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 09/07/2022] [Accepted: 09/11/2022] [Indexed: 12/14/2022]
Abstract
INTRODUCTION/AIMS Mutations in the SCN4A gene encoding a voltage-gated sodium channel (Nav1.4) cause hyperkalemic periodic paralysis (HyperPP) and hypokalemic periodic paralysis (HypoPP). Typically, both HyperPP and HypoPP are considered as monogenic disorders caused by a missense mutation with a large functional effect. However, a few cases with atypical periodic paralysis phenotype have been caused by multiple mutations in ion-channel genes expressed in skeletal muscles. In this study we investigated the underlying pathogenic mechanisms in such cases. METHODS We clinically assessed two families: proband 1 with HyperPP and proband 2 with atypical periodic paralysis with hypokalemia. Genetic analyses were performed by next-generation sequencing and conventional Sanger sequencing, followed by electrophysiological analyses of the mutant Nav1.4 channels expressed in human embryonic kidney 293T (HEK293T) cells using the whole-cell patch-clamp technique. RESULTS In proband 1, K880del was identified in the SCN4A gene. In proband 2, K880del and a novel mutation, R1639H, were identified in the same allele of the SCN4A gene. Functional analyses revealed that the K880del in SCN4A has a weak functional effect on hNav1.4, increasing the excitability of the sarcolemma, which could represent a potential pathogenic factor. Although R1639H alone did not reveal functional changes strong enough to be pathogenic, Nav1.4 with both K880del and R1639H showed enhanced activation compared with K880del alone, indicating that R1639H may modify the hNav1.4 channel function. DISCUSSION A cumulative effect of variants with small functional alterations may be considered as the underpinning oligogenic pathogenic mechanisms for the unusual phenotype of periodic paralysis.
Collapse
Affiliation(s)
- Maki Shibano
- Clinical Neurophysiology, Department of Clinical Laboratory and Biomedical Sciences, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Tomoya Kubota
- Clinical Neurophysiology, Department of Clinical Laboratory and Biomedical Sciences, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Norito Kokubun
- Department of Neurology, Dokkyo Medical University, Shimotsuga, Japan
| | - Yosuke Miyaji
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Hiroko Kuriki
- Department of Clinical Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yuzuru Ito
- Department of Endocrinology and Metabolism, Yokohama City University Medical Center, Yokohama, Japan
| | - Haruka Hamanoue
- Department of Clinical Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Masanori P Takahashi
- Clinical Neurophysiology, Department of Clinical Laboratory and Biomedical Sciences, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| |
Collapse
|
47
|
Pajouhesh H, Delwig A, Beckley JT, Klas S, Monteleone D, Zhou X, Luu G, Du Bois J, Hunter JC, Mulcahy JV. Discovery of Selective Inhibitors of Na V1.7 Templated on Saxitoxin as Therapeutics for Pain. ACS Med Chem Lett 2022; 13:1763-1768. [PMID: 36385936 PMCID: PMC9661704 DOI: 10.1021/acsmedchemlett.2c00378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 10/05/2022] [Indexed: 11/28/2022] Open
Abstract
The voltage-gated sodium channel isoform NaV1.7 has drawn widespread interest as a target for non-opioid, investigational new drugs to treat pain. Selectivity over homologous, off-target sodium channel isoforms, which are expressed in peripheral motor neurons, the central nervous system, skeletal muscle and the heart, poses a significant challenge to the development of small molecule inhibitors of NaV1.7. Most inhibitors of NaV1.7 disclosed to date belong to a class of aryl and acyl sulfonamides that preferentially bind to an inactivated conformation of the channel. By taking advantage of a sequence variation unique to primate NaV1.7 in the extracellular pore of the channel, a series of bis-guanidinium analogues of the natural product, saxitoxin, has been identified that are potent against the resting conformation of the channel. A compound of interest, 25, exhibits >600-fold selectivity over off-target sodium channel isoforms and is efficacious in a preclinical model of acute pain.
Collapse
Affiliation(s)
- Hassan Pajouhesh
- SiteOne
Therapeutics, Inc., South San Francisco, California 94080, United States
| | - Anton Delwig
- SiteOne
Therapeutics, Inc., South San Francisco, California 94080, United States
| | - Jacob T. Beckley
- SiteOne
Therapeutics, Inc., Bozeman, Montana 59715, United States
| | - Sheri Klas
- SiteOne
Therapeutics, Inc., Bozeman, Montana 59715, United States
| | - Dennis Monteleone
- SiteOne
Therapeutics, Inc., South San Francisco, California 94080, United States
| | - Xiang Zhou
- SiteOne
Therapeutics, Inc., South San Francisco, California 94080, United States
| | - George Luu
- SiteOne
Therapeutics, Inc., South San Francisco, California 94080, United States
| | - J. Du Bois
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - John C. Hunter
- SiteOne
Therapeutics, Inc., South San Francisco, California 94080, United States
| | - John V. Mulcahy
- SiteOne
Therapeutics, Inc., South San Francisco, California 94080, United States
| |
Collapse
|
48
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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
|
49
|
Liu JJ, Eyring KW, König GM, Kostenis E, Tsien RW. Oxytocin-Modulated Ion Channel Ensemble Controls Depolarization, Integration and Burst Firing in CA2 Pyramidal Neurons. J Neurosci 2022; 42:7707-20. [PMID: 36414006 DOI: 10.1523/JNEUROSCI.0921-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/02/2022] [Accepted: 08/26/2022] [Indexed: 12/14/2022] Open
Abstract
Oxytocin (OXT) and OXT receptor (OXTR)-mediated signaling control excitability, firing patterns, and plasticity of hippocampal CA2 pyramidal neurons, which are pivotal in generation of brain oscillations and social memory. Nonetheless, the ionic mechanisms underlying OXTR-induced effects in CA2 neurons are not fully understood. Using slice physiology in a reporter mouse line and interleaved current-clamp and voltage-clamp experiments, we systematically identified the ion channels modulated by OXT signaling in CA2 pyramidal cells (PYRs) in mice of both sexes and explored how changes in channel conductance support altered electrical activity. Activation of OXTRs inhibits an outward potassium current mediated by inward rectifier potassium channels (I Kir) and thus favoring membrane depolarization. Concomitantly, OXT signaling also diminishes inward current mediated by hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels (I h), providing a hyperpolarizing drive. The combined reduction in both I Kir and I h synergistically elevate the membrane resistance and favor dendritic integration while the membrane potential is restrained from quickly depolarizing from rest. As a result, the responsiveness of CA2 PYRs to synaptic inputs is highly sharpened during OXTR activation. Unexpectedly, OXTR signaling also strongly enhances a tetrodotoxin-resistant (TTX-R), voltage-gated sodium current that helps drive the membrane potential to spike threshold and thus promote rhythmic firing. This novel array of OXTR-stimulated ionic mechanisms operates in close coordination and underpins OXT-induced burst firing, a key step in CA2 PYRs' contribution to hippocampal information processing and broader influence on brain circuitry. Our study deepens our understanding of underpinnings of OXT-promoted social memory and general neuropeptidergic control of cognitive states.SIGNIFICANCE STATEMENT Oxytocin (OXT) plays key roles in reproduction, parenting and social and emotional behavior, and deficiency in OXT receptor (OXTR) signaling may contribute to neuropsychiatric disorders. We identified a novel array of OXTR-modulated ion channels that operate in close coordination to retune hippocampal CA2 pyramidal neurons, enhancing responsiveness to synaptic inputs and sculpting output. OXTR signaling inhibits both potassium conductance (I Kir) and mixed cation conductance (I h), engaging opposing influences on membrane potential, stabilizing it while synergistically elevating membrane resistance and electrotonic spread. OXT signaling also facilitates a tetrodotoxin-resistant (TTX-R) Na+ current, not previously described in hippocampus (HP), engaged on further depolarization. This TTX-R current lowers the spike threshold and supports rhythmic depolarization and burst firing, a potent driver of downstream circuitry.
Collapse
|
50
|
Hill SF, Ziobro JM, Jafar‐Nejad P, Rigo F, Meisler MH. Genetic interaction between Scn8a and potassium channel genes Kcna1 and Kcnq2. Epilepsia 2022; 63:e125-e131. [PMID: 35892317 PMCID: PMC9804156 DOI: 10.1111/epi.17374] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 07/24/2022] [Accepted: 07/25/2022] [Indexed: 01/07/2023]
Abstract
Voltage-gated sodium and potassium channels regulate the initiation and termination of neuronal action potentials. Gain-of-function mutations of sodium channel Scn8a and loss-of-function mutations of potassium channels Kcna1 and Kcnq2 increase neuronal activity and lead to seizure disorders. We tested the hypothesis that reducing the expression of Scn8a would compensate for loss-of-function mutations of Kcna1 or Kcnq2. Scn8a expression was reduced by the administration of an antisense oligonucleotide (ASO). This treatment lengthened the survival of the Kcn1a and Kcnq2 mutants, and reduced the seizure frequency in the Kcnq2 mutant mice. These observations suggest that reduction of SCN8A may be therapeutic for genetic epilepsies resulting from mutations in these potassium channel genes.
Collapse
Affiliation(s)
- Sophie F. Hill
- Neuroscience Graduate ProgramUniversity of MichiganAnn ArborMichiganUSA,Department of Human GeneticsUniversity of MichiganAnn ArborMichiganUSA
| | - Julie M. Ziobro
- Department of PediatricsUniversity of MichiganAnn ArborMichiganUSA
| | | | - Frank Rigo
- Ionis PharmaceuticalsCarlsbadCaliforniaUSA
| | - Miriam H. Meisler
- Neuroscience Graduate ProgramUniversity of MichiganAnn ArborMichiganUSA,Department of Human GeneticsUniversity of MichiganAnn ArborMichiganUSA,Department of NeurologyUniversity of MichiganAnn ArborMichiganUSA
| |
Collapse
|