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McCarthy CI, Kavalali ET. Nano-organization of synaptic calcium signaling. Biochem Soc Trans 2024; 52:1459-1471. [PMID: 38752834 DOI: 10.1042/bst20231385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/17/2024] [Accepted: 05/03/2024] [Indexed: 06/27/2024]
Abstract
Recent studies suggest an exquisite structural nano-organization within single synapses, where sites of evoked fusion - marked by clustering of synaptic vesicles, active zone proteins and voltage-gated calcium channels - are directly juxtaposed to postsynaptic receptor clusters within nanocolumns. This direct nanometer scale alignment between presynaptic fusion apparatus and postsynaptic receptors is thought to ensure the fidelity of synaptic signaling and possibly allow multiple distinct signals to occur without interference from each other within a single active zone. The functional specificity of this organization is made possible by the inherent nano-organization of calcium signals, where all the different calcium sources such as voltage-gated calcium channels, intracellular stores and store-operated calcium entry have dedicated local targets within their nanodomain to ensure precision of action. Here, we discuss synaptic nano-organization from the perspective of calcium signals, where some of the principal findings from early work in the 1980s continue to inspire current studies that exploit new genetic tools and super-resolution imaging technologies.
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Affiliation(s)
- Clara I McCarthy
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, U.S.A
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, U.S.A
| | - Ege T Kavalali
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, U.S.A
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, U.S.A
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2
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Ren H, Li F, Wang M, Liu G, Li D, Wang R, Chen Y, Tang Y, Wang Y, Jin R, Huang Q, Xing L, Chen X, Wang J, Guo C, Zhu B. An Ion-Mediated Spiking Chemical Neuron based on Mott Memristor. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2403678. [PMID: 38887824 DOI: 10.1002/adma.202403678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/31/2024] [Indexed: 06/20/2024]
Abstract
Artificial spiking neurons capable of interpreting ionic information into electrical spikes are critical to mimic biological signaling systems. Mott memristors are attractive for constructing artificial spiking neurons due to their simple structure, low energy consumption, and rich neural dynamics. However, challenges remain in achieving ion-mediated spiking and biohybrid-interfacing in Mott neurons. Here, a biomimetic spiking chemical neuron (SCN) utilizing an NbOx Mott memristor and oxide field-effect transistor-type chemical sensor is introduced. The SCN exhibits both excitation and inhibition spiking behaviors toward ionic concentrations akin to biological neural systems. It demonstrates spiking responses across physiological and pathological Na+ concentrations (1-200 × 10-3 m). The Na+-mediated SCN enables both frequency encoding and time-to-first-spike coding schemes, illustrating the rich neural dynamics of Mott neuron. In addition, the SCN interfaced with L929 cells facilitates real-time modulation of ion-mediated spiking under both normal and salty cellular microenvironments.
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Affiliation(s)
- Huihui Ren
- School of Materials and Engineering, Zhejiang University, Hangzhou, 310027, China
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
| | - Fanfan Li
- School of Materials and Engineering, Zhejiang University, Hangzhou, 310027, China
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
| | - Min Wang
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
| | - Guolei Liu
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
| | - Dingwei Li
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
| | - Rui Wang
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
| | - Yitong Chen
- School of Materials and Engineering, Zhejiang University, Hangzhou, 310027, China
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
| | - Yingjie Tang
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
| | - Yan Wang
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
| | - Ran Jin
- School of Materials and Engineering, Zhejiang University, Hangzhou, 310027, China
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
| | - Qi Huang
- Westlake Institute for Optoelectronics, Hangzhou, 311421, China
| | - Lixiang Xing
- Westlake Institute for Optoelectronics, Hangzhou, 311421, China
| | - Xiaopeng Chen
- Enovated3D (Hangzhou) Technology Development Co. Ltd., Hangzhou, 310051, China
| | - Juan Wang
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Chengchen Guo
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
| | - Bowen Zhu
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China
- Westlake Institute for Optoelectronics, Hangzhou, 311421, China
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3
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Pozzi E, Terribile G, Cherchi L, Di Girolamo S, Sancini G, Alberti P. Ion Channel and Transporter Involvement in Chemotherapy-Induced Peripheral Neurotoxicity. Int J Mol Sci 2024; 25:6552. [PMID: 38928257 PMCID: PMC11203899 DOI: 10.3390/ijms25126552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 06/06/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
The peripheral nervous system can encounter alterations due to exposure to some of the most commonly used anticancer drugs (platinum drugs, taxanes, vinca alkaloids, proteasome inhibitors, thalidomide), the so-called chemotherapy-induced peripheral neurotoxicity (CIPN). CIPN can be long-lasting or even permanent, and it is detrimental for the quality of life of cancer survivors, being associated with persistent disturbances such as sensory loss and neuropathic pain at limb extremities due to a mostly sensory axonal polyneuropathy/neuronopathy. In the state of the art, there is no efficacious preventive/curative treatment for this condition. Among the reasons for this unmet clinical and scientific need, there is an uncomplete knowledge of the pathogenetic mechanisms. Ion channels and transporters are pivotal elements in both the central and peripheral nervous system, and there is a growing body of literature suggesting that they might play a role in CIPN development. In this review, we first describe the biophysical properties of these targets and then report existing data for the involvement of ion channels and transporters in CIPN, thus paving the way for new approaches/druggable targets to cure and/or prevent CIPN.
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Affiliation(s)
- Eleonora Pozzi
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
| | - Giulia Terribile
- Human Physiology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.T.); (G.S.)
| | - Laura Cherchi
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
| | - Sara Di Girolamo
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
| | - Giulio Sancini
- Human Physiology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.T.); (G.S.)
| | - Paola Alberti
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (E.P.); (L.C.); (S.D.G.)
- Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy
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Zhao K, Li Y, Lai H, Niu R, Li H, He S, Su Z, Gui Y, Ren L, Yang X, Zhou L. Alterations in HCN1 expression and distribution during epileptogenesis in rats. Epilepsy Res 2024; 202:107355. [PMID: 38555654 DOI: 10.1016/j.eplepsyres.2024.107355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 03/10/2024] [Accepted: 03/21/2024] [Indexed: 04/02/2024]
Abstract
BACKGROUND The hyperpolarization-activated cyclic nucleotide-gated cation channel (HCN1) is predominantly located in key regions associated with epilepsy, such as the neocortex and hippocampus. Under normal physiological conditions, HCN1 plays a crucial role in the excitatory and inhibitory regulation of neuronal networks. In temporal lobe epilepsy, the expression of HCN1 is decreased in the hippocampi of both animal models and patients. However, whether HCN1 expression changes during epileptogenesis preceding spontaneous seizures remains unclear. OBJECTIVE The aim of this study was to determine whether the expression of HCN1 is altered during the epileptic prodromal phase, thereby providing evidence for its role in epileptogenesis. METHODS We utilized a cobalt wire-induced rat epilepsy model to observe changes in HCN1 during epileptogenesis and epilepsy. Additionally, we also compared HCN1 alterations in epileptogenic tissues between cobalt wire- and pilocarpine-induced epilepsy rat models. Long-term video EEG recordings were used to confirm seizures development. Transcriptional changes, translation, and distribution of HCN1 were assessed using high-throughput transcriptome sequencing, total protein extraction, membrane and cytoplasmic protein fractionation, western blotting, immunohistochemistry, and immunofluorescence techniques. RESULTS In the cobalt wire-induced rat epilepsy model during the epileptogenesis phase, total HCN1 mRNA and protein levels were downregulated. Specifically, the membrane expression of HCN1 was decreased, whereas cytoplasmic HCN1 expression showed no significant change. The distribution of HCN1 in the distal dendrites of neurons decreased. During the epilepsy period, similar HCN1 alterations were observed in the neocortex of rats with cobalt wire-induced epilepsy and hippocampus of rats with lithium pilocarpine-induced epilepsy, including downregulation of mRNA levels, decreased total protein expression, decreased membrane expression, and decreased distal dendrite expression. CONCLUSIONS Alterations in HCN1 expression and distribution are involved in epileptogenesis beyond their association with seizure occurrence. Similarities in HCN1 alterations observed in epileptogenesis-related tissues from different models suggest a shared pathophysiological pathway in epileptogenesis involving HCN1 dysregulation. Therefore, the upregulation of HCN1 expression in neurons, maintenance of the HCN1 membrane, and distal dendrite distribution in neurons may represent promising disease-modifying strategies in epilepsy.
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Affiliation(s)
- Ke Zhao
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China; Guangzhou National Laboratory, Guangzhou, China; Department of Neurology, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, China
| | - Yinchao Li
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | | | - Ruili Niu
- Guangzhou National Laboratory, Guangzhou, China
| | - Huifeng Li
- Guangzhou National Laboratory, Guangzhou, China
| | - Shipei He
- Guangzhou National Laboratory, Guangzhou, China
| | - Zhengwei Su
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Yue Gui
- Guangzhou National Laboratory, Guangzhou, China
| | - Lijie Ren
- Department of Neurology, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, China.
| | | | - Liemin Zhou
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China.
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Ramaswamy S. Data-driven multiscale computational models of cortical and subcortical regions. Curr Opin Neurobiol 2024; 85:102842. [PMID: 38320453 DOI: 10.1016/j.conb.2024.102842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 02/08/2024]
Abstract
Data-driven computational models of neurons, synapses, microcircuits, and mesocircuits have become essential tools in modern brain research. The goal of these multiscale models is to integrate and synthesize information from different levels of brain organization, from cellular properties, dendritic excitability, and synaptic dynamics to microcircuits, mesocircuits, and ultimately behavior. This article surveys recent advances in the genesis of data-driven computational models of mammalian neural networks in cortical and subcortical areas. I discuss the challenges and opportunities in developing data-driven multiscale models, including the need for interdisciplinary collaborations, the importance of model validation and comparison, and the potential impact on basic and translational neuroscience research. Finally, I highlight future directions and emerging technologies that will enable more comprehensive and predictive data-driven models of brain function and dysfunction.
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Affiliation(s)
- Srikanth Ramaswamy
- Neural Circuits Laboratory, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4HH, United Kingdom.
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Yuan T, Wang Y, Jin Y, Yang H, Xu S, Zhang H, Chen Q, Li N, Ma X, Song H, Peng C, Geng Z, Dong J, Duan G, Sun Q, Yang Y, Yang F, Huang Z. Coupling of Slack and Na V1.6 sensitizes Slack to quinidine blockade and guides anti-seizure strategy development. eLife 2024; 12:RP87559. [PMID: 38289338 PMCID: PMC10942592 DOI: 10.7554/elife.87559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024] Open
Abstract
Quinidine has been used as an anticonvulsant to treat patients with KCNT1-related epilepsy by targeting gain-of-function KCNT1 pathogenic mutant variants. However, the detailed mechanism underlying quinidine's blockade against KCNT1 (Slack) remains elusive. Here, we report a functional and physical coupling of the voltage-gated sodium channel NaV1.6 and Slack. NaV1.6 binds to and highly sensitizes Slack to quinidine blockade. Homozygous knockout of NaV1.6 reduces the sensitivity of native sodium-activated potassium currents to quinidine blockade. NaV1.6-mediated sensitization requires the involvement of NaV1.6's N- and C-termini binding to Slack's C-terminus and is enhanced by transient sodium influx through NaV1.6. Moreover, disrupting the Slack-NaV1.6 interaction by viral expression of Slack's C-terminus can protect against SlackG269S-induced seizures in mice. These insights about a Slack-NaV1.6 complex challenge the traditional view of 'Slack as an isolated target' for anti-epileptic drug discovery efforts and can guide the development of innovative therapeutic strategies for KCNT1-related epilepsy.
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Affiliation(s)
- Tian Yuan
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Yifan Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Yuchen Jin
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Hui Yang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Shuai Xu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Heng Zhang
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang UniversityZhejiangChina
| | - Qian Chen
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Na Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Xinyue Ma
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Huifang Song
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Chao Peng
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Ze Geng
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Jie Dong
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Guifang Duan
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Qi Sun
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue UniversityWest LafayetteUnited States
| | - Fan Yang
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang UniversityZhejiangChina
- Department of Biophysics, Kidney Disease Center of the First Affiliated Hospital, Zhejiang University School of Medicine, HangzhouZhejiangChina
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
- IDG/McGovern Institute for Brain Research, Peking UniversityBeijingChina
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Stengl M, Schneider AC. Contribution of membrane-associated oscillators to biological timing at different timescales. Front Physiol 2024; 14:1243455. [PMID: 38264332 PMCID: PMC10803594 DOI: 10.3389/fphys.2023.1243455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 12/12/2023] [Indexed: 01/25/2024] Open
Abstract
Environmental rhythms such as the daily light-dark cycle selected for endogenous clocks. These clocks predict regular environmental changes and provide the basis for well-timed adaptive homeostasis in physiology and behavior of organisms. Endogenous clocks are oscillators that are based on positive feedforward and negative feedback loops. They generate stable rhythms even under constant conditions. Since even weak interactions between oscillators allow for autonomous synchronization, coupling/synchronization of oscillators provides the basis of self-organized physiological timing. Amongst the most thoroughly researched clocks are the endogenous circadian clock neurons in mammals and insects. They comprise nuclear clockworks of transcriptional/translational feedback loops (TTFL) that generate ∼24 h rhythms in clock gene expression entrained to the environmental day-night cycle. It is generally assumed that this TTFL clockwork drives all circadian oscillations within and between clock cells, being the basis of any circadian rhythm in physiology and behavior of organisms. Instead of the current gene-based hierarchical clock model we provide here a systems view of timing. We suggest that a coupled system of autonomous TTFL and posttranslational feedback loop (PTFL) oscillators/clocks that run at multiple timescales governs adaptive, dynamic homeostasis of physiology and behavior. We focus on mammalian and insect neurons as endogenous oscillators at multiple timescales. We suggest that neuronal plasma membrane-associated signalosomes constitute specific autonomous PTFL clocks that generate localized but interlinked oscillations of membrane potential and intracellular messengers with specific endogenous frequencies. In each clock neuron multiscale interactions of TTFL and PTFL oscillators/clocks form a temporally structured oscillatory network with a common complex frequency-band comprising superimposed multiscale oscillations. Coupling between oscillator/clock neurons provides the next level of complexity of an oscillatory network. This systemic dynamic network of molecular and cellular oscillators/clocks is suggested to form the basis of any physiological homeostasis that cycles through dynamic homeostatic setpoints with a characteristic frequency-band as hallmark. We propose that mechanisms of homeostatic plasticity maintain the stability of these dynamic setpoints, whereas Hebbian plasticity enables switching between setpoints via coupling factors, like biogenic amines and/or neuropeptides. They reprogram the network to a new common frequency, a new dynamic setpoint. Our novel hypothesis is up for experimental challenge.
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Affiliation(s)
- Monika Stengl
- Department of Biology, Animal Physiology/Neuroethology, University of Kassel, Kassel, Germany
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8
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Housley SN, Powers RK, Nardelli P, Lee S, Blum K, Bewick GS, Banks RW, Cope TC. Biophysical model of muscle spindle encoding. Exp Physiol 2024; 109:55-65. [PMID: 36966478 PMCID: PMC10988694 DOI: 10.1113/ep091099] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/09/2023] [Indexed: 03/27/2023]
Abstract
Muscle spindles encode mechanosensory information by mechanisms that remain only partially understood. Their complexity is expressed in mounting evidence of various molecular mechanisms that play essential roles in muscle mechanics, mechanotransduction and intrinsic modulation of muscle spindle firing behaviour. Biophysical modelling provides a tractable approach to achieve more comprehensive mechanistic understanding of such complex systems that would be difficult/impossible by more traditional, reductionist means. Our objective here was to construct the first integrative biophysical model of muscle spindle firing. We leveraged current knowledge of muscle spindle neuroanatomy and in vivo electrophysiology to develop and validate a biophysical model that reproduces key in vivo muscle spindle encoding characteristics. Crucially, to our knowledge, this is the first computational model of mammalian muscle spindle that integrates the asymmetric distribution of known voltage-gated ion channels (VGCs) with neuronal architecture to generate realistic firing profiles, both of which seem likely to be of great biophysical importance. Results predict that particular features of neuronal architecture regulate specific characteristics of Ia encoding. Computational simulations also predict that the asymmetric distribution and ratios of VGCs is a complementary and, in some instances, orthogonal means to regulate Ia encoding. These results generate testable hypotheses and highlight the integral role of peripheral neuronal structure and ion channel composition and distribution in somatosensory signalling.
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Affiliation(s)
| | - Randal K. Powers
- Department of Physiology and BiophysicsUniversity of WashingtonSeattleWAUSA
| | - Paul Nardelli
- School of Biological SciencesGeorgia Institute of TechnologyAtlantaGA
| | - Sebinne Lee
- School of Biological SciencesGeorgia Institute of TechnologyAtlantaGA
| | - Kyle Blum
- Department of Physiology, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Guy S. Bewick
- Institute of Medical ScienceUniversity of AberdeenAberdeenUK
| | | | - Timothy C. Cope
- School of Biological SciencesGeorgia Institute of TechnologyAtlantaGA
- W. H. Coulter Department of Biomedical EngineeringEmory University and Georgia Institute of Technology, Georgia Institute of TechnologyAtlantaGA
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9
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Elhadi K, Daiwile AP, Cadet JL. Modeling methamphetamine use disorder and relapse in animals: short- and long-term epigenetic, transcriptional., and biochemical consequences in the rat brain. Neurosci Biobehav Rev 2023; 155:105440. [PMID: 38707245 PMCID: PMC11068368 DOI: 10.1016/j.neubiorev.2023.105440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
Methamphetamine use disorder (MUD) is a neuropsychiatric disorder characterized by binge drug taking episodes, intervals of abstinence, and relapses to drug use even during treatment. MUD has been modeled in rodents and investigators are attempting to identify its molecular bases. Preclinical experiments have shown that different schedules of methamphetamine self-administration can cause diverse transcriptional changes in the dorsal striatum of Sprague-Dawley rats. In the present review, we present data on differentially expressed genes (DEGs) identified in the rat striatum following methamphetamine intake. These include genes involved in transcription regulation, potassium channel function, and neuroinflammation. We then use the striatal data to discuss the potential significance of the molecular changes induced by methamphetamine by reviewing concordant or discordant data from the literature. This review identified potential molecular targets for pharmacological interventions. Nevertheless, there is a need for more research on methamphetamine-induced transcriptional consequences in various brain regions. These data should provide a more detailed neuroanatomical map of methamphetamine-induced changes and should better inform therapeutic interventions against MUD.
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Affiliation(s)
- Khalid Elhadi
- Molecular Neuropsychiatry Research Branch, NIH/NIDA Intramural Research Program, Baltimore, MD, 21224
| | - Atul P. Daiwile
- Molecular Neuropsychiatry Research Branch, NIH/NIDA Intramural Research Program, Baltimore, MD, 21224
| | - Jean Lud Cadet
- Molecular Neuropsychiatry Research Branch, NIH/NIDA Intramural Research Program, Baltimore, MD, 21224
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10
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Bhattacherjee A, Zhang C, Watson BR, Djekidel MN, Moffitt JR, Zhang Y. Spatial transcriptomics reveals the distinct organization of mouse prefrontal cortex and neuronal subtypes regulating chronic pain. Nat Neurosci 2023; 26:1880-1893. [PMID: 37845544 PMCID: PMC10620082 DOI: 10.1038/s41593-023-01455-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 09/07/2023] [Indexed: 10/18/2023]
Abstract
The prefrontal cortex (PFC) is a complex brain region that regulates diverse functions ranging from cognition, emotion and executive action to even pain processing. To decode the cellular and circuit organization of such diverse functions, we employed spatially resolved single-cell transcriptome profiling of the adult mouse PFC. Results revealed that PFC has distinct cell-type composition and gene-expression patterns relative to neighboring cortical areas-with neuronal excitability-regulating genes differently expressed. These cellular and molecular features are further segregated within PFC subregions, alluding to the subregion-specificity of several PFC functions. PFC projects to major subcortical targets through combinations of neuronal subtypes, which emerge in a target-intrinsic fashion. Finally, based on these features, we identified distinct cell types and circuits in PFC underlying chronic pain, an escalating healthcare challenge with limited molecular understanding. Collectively, this comprehensive map will facilitate decoding of discrete molecular, cellular and circuit mechanisms underlying specific PFC functions in health and disease.
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Affiliation(s)
- Aritra Bhattacherjee
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Division of Hematology/Oncology, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
| | - Chao Zhang
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Division of Hematology/Oncology, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
| | - Brianna R Watson
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Mohamed Nadhir Djekidel
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Division of Hematology/Oncology, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
- Center for Applied Bioinformatics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Jeffrey R Moffitt
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
| | - Yi Zhang
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA, USA.
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
- Division of Hematology/Oncology, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA.
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
- Harvard Stem Cell Institute, Boston, MA, USA.
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11
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Shi X, Lu C, Corman A, Nikish A, Zhou Y, Platt RJ, Iossifov I, Zhang F, Pan JQ, Sanjana NE. Heterozygous deletion of the autism-associated gene CHD8 impairs synaptic function through widespread changes in gene expression and chromatin compaction. Am J Hum Genet 2023; 110:1750-1768. [PMID: 37802044 PMCID: PMC10577079 DOI: 10.1016/j.ajhg.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 10/08/2023] Open
Abstract
Whole-exome sequencing of autism spectrum disorder (ASD) probands and unaffected family members has identified many genes harboring de novo variants suspected to play a causal role in the disorder. Of these, chromodomain helicase DNA-binding protein 8 (CHD8) is the most recurrently mutated. Despite the prevalence of CHD8 mutations, we have little insight into how CHD8 loss affects genome organization or the functional consequences of these molecular alterations in neurons. Here, we engineered two isogenic human embryonic stem cell lines with CHD8 loss-of-function mutations and characterized differences in differentiated human cortical neurons. We identified hundreds of genes with altered expression, including many involved in neural development and excitatory synaptic transmission. Field recordings and single-cell electrophysiology revealed a 3-fold decrease in firing rates and synaptic activity in CHD8+/- neurons, as well as a similar firing-rate deficit in primary cortical neurons from Chd8+/- mice. These alterations in neuron and synapse function can be reversed by CHD8 overexpression. Moreover, CHD8+/- neurons displayed a large increase in open chromatin across the genome, where the greatest change in compaction was near autism susceptibility candidate 2 (AUTS2), which encodes a transcriptional regulator implicated in ASD. Genes with changes in chromatin accessibility and expression in CHD8+/- neurons have significant overlap with genes mutated in probands for ASD, intellectual disability, and schizophrenia but not with genes mutated in healthy controls or other disease cohorts. Overall, this study characterizes key molecular alterations in genome structure and expression in CHD8+/- neurons and links these changes to impaired neuronal and synaptic function.
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Affiliation(s)
- Xi Shi
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA; Broad Institute, Cambridge, MA, USA; Stanley Center for Psychiatric Research, Broad Institute, Cambridge, MA, USA
| | - Congyi Lu
- New York Genome Center, New York, NY, USA; Department of Biology, New York University, New York, NY, USA
| | - Alba Corman
- New York Genome Center, New York, NY, USA; Department of Biology, New York University, New York, NY, USA
| | - Alexandra Nikish
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA; Broad Institute, Cambridge, MA, USA
| | - Yang Zhou
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada; Montreal Neurological Institute, Montreal, QC, Canada
| | - Randy J Platt
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Ivan Iossifov
- New York Genome Center, New York, NY, USA; Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Feng Zhang
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Bioengineering, Massachusetts Institute of Technology, Cambridge, MA, USA; Broad Institute, Cambridge, MA, USA
| | - Jen Q Pan
- Stanley Center for Psychiatric Research, Broad Institute, Cambridge, MA, USA.
| | - Neville E Sanjana
- New York Genome Center, New York, NY, USA; Department of Biology, New York University, New York, NY, USA.
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12
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Huang X, Miyata H, Wang H, Mori G, Iida-Norita R, Ikawa M, Percudani R, Chung JJ. A CUG-initiated CATSPERθ functions in the CatSper channel assembly and serves as a checkpoint for flagellar trafficking. Proc Natl Acad Sci U S A 2023; 120:e2304409120. [PMID: 37725640 PMCID: PMC10523455 DOI: 10.1073/pnas.2304409120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 08/10/2023] [Indexed: 09/21/2023] Open
Abstract
Calcium signaling is critical for successful fertilization. In spermatozoa, calcium influx into the sperm flagella mediated by the sperm-specific CatSper calcium channel is necessary for hyperactivated motility and male fertility. CatSper is a macromolecular complex and is repeatedly arranged in zigzag rows within four linear nanodomains along the sperm flagella. Here, we report that the Tmem249-encoded transmembrane (TM) domain-containing protein, CATSPERθ is essential for the CatSper channel assembly during sperm tail formation. CATSPERθ facilitates the channel assembly by serving as a scaffold for a pore-forming subunit CATSPER4. CATSPERθ is specifically localized at the interface of a CatSper dimer and can self-interact, suggesting its potential role in CatSper dimer formation. Male mice lacking CATSPERθ are infertile because the sperm lack the entire CatSper channel from sperm flagella, rendering sperm unable to hyperactivate, regardless of their normal expression in the testis. In contrast, genetic abrogation of any of the other CatSper TM subunits results in loss of CATSPERθ protein in the spermatid cells during spermatogenesis. CATSPERθ might act as a checkpoint for the properly assembled CatSper channel complex to traffic to sperm flagella. This study provides insights into the CatSper channel assembly and elucidates the physiological role of CATSPERθ in sperm motility and male fertility.
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Affiliation(s)
- Xiaofang Huang
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT06510
| | - Haruhiko Miyata
- Research Institute for Microbial Diseases, Osaka University, Suita565-0871, Japan
| | - Huafeng Wang
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT06510
| | - Giulia Mori
- Department of Chemistry, Life sciences, and Environmental Sustainability, University of Parma, Parma43124, Italy
| | - Rie Iida-Norita
- Research Institute for Microbial Diseases, Osaka University, Suita565-0871, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita565-0871, Japan
| | - Riccardo Percudani
- Department of Chemistry, Life sciences, and Environmental Sustainability, University of Parma, Parma43124, Italy
| | - Jean-Ju Chung
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT06510
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, Yale University, New Haven, CT06510
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13
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Nsasra E, Dahan I, Eichler J, Yifrach O. It's Time for Entropic Clocks: The Roles of Random Chain Protein Sequences in Timing Ion Channel Processes Underlying Action Potential Properties. ENTROPY (BASEL, SWITZERLAND) 2023; 25:1351. [PMID: 37761650 PMCID: PMC10527868 DOI: 10.3390/e25091351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/10/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023]
Abstract
In recent years, it has become clear that intrinsically disordered protein segments play diverse functional roles in many cellular processes, thus leading to a reassessment of the classical structure-function paradigm. One class of intrinsically disordered protein segments is entropic clocks, corresponding to unstructured random protein chains involved in timing cellular processes. Such clocks were shown to modulate ion channel processes underlying action potential generation, propagation, and transmission. In this review, we survey the role of entropic clocks in timing intra- and inter-molecular binding events of voltage-activated potassium channels involved in gating and clustering processes, respectively, and where both are known to occur according to a similar 'ball and chain' mechanism. We begin by delineating the thermodynamic and timing signatures of a 'ball and chain'-based binding mechanism involving entropic clocks, followed by a detailed analysis of the use of such a mechanism in the prototypical Shaker voltage-activated K+ channel model protein, with particular emphasis on ion channel clustering. We demonstrate how 'chain'-level alternative splicing of the Kv channel gene modulates entropic clock-based 'ball and chain' inactivation and clustering channel functions. As such, the Kv channel model system exemplifies how linkage between alternative splicing and intrinsic disorder enables the functional diversity underlying changes in electrical signaling.
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Affiliation(s)
| | | | | | - Ofer Yifrach
- Department of Life Sciences, School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105, Israel; (E.N.); (J.E.)
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14
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Alam KA, Svalastoga P, Martinez A, Glennon JC, Haavik J. Potassium channels in behavioral brain disorders. Molecular mechanisms and therapeutic potential: A narrative review. Neurosci Biobehav Rev 2023; 152:105301. [PMID: 37414376 DOI: 10.1016/j.neubiorev.2023.105301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/26/2023] [Accepted: 06/30/2023] [Indexed: 07/08/2023]
Abstract
Potassium channels (K+-channels) selectively control the passive flow of potassium ions across biological membranes and thereby also regulate membrane excitability. Genetic variants affecting many of the human K+-channels are well known causes of Mendelian disorders within cardiology, neurology, and endocrinology. K+-channels are also primary targets of many natural toxins from poisonous organisms and drugs used within cardiology and metabolism. As genetic tools are improving and larger clinical samples are being investigated, the spectrum of clinical phenotypes implicated in K+-channels dysfunction is rapidly expanding, notably within immunology, neurosciences, and metabolism. K+-channels that previously were considered to be expressed in only a few organs and to have discrete physiological functions, have recently been found in multiple tissues and with new, unexpected functions. The pleiotropic functions and patterns of expression of K+-channels may provide additional therapeutic opportunities, along with new emerging challenges from off-target effects. Here we review the functions and therapeutic potential of K+-channels, with an emphasis on the nervous system, roles in neuropsychiatric disorders and their involvement in other organ systems and diseases.
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Affiliation(s)
| | - Pernille Svalastoga
- Mohn Center for Diabetes Precision Medicine, Department of Clinical Science, University of Bergen, Bergen, Norway; Children and Youth Clinic, Haukeland University Hospital, Bergen, Norway
| | | | - Jeffrey Colm Glennon
- Conway Institute for Biomolecular and Biomedical Research, School of Medicine, University College Dublin, Dublin, Ireland.
| | - Jan Haavik
- Department of Biomedicine, University of Bergen, Norway; Division of Psychiatry, Haukeland University Hospital, Norway.
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15
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Topczewska A, Giacalone E, Pratt WS, Migliore M, Dolphin AC, Shah MM. T-type Ca 2+ and persistent Na + currents synergistically elevate ventral, not dorsal, entorhinal cortical stellate cell excitability. Cell Rep 2023; 42:112699. [PMID: 37368752 PMCID: PMC10687207 DOI: 10.1016/j.celrep.2023.112699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 03/08/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023] Open
Abstract
Dorsal and ventral medial entorhinal cortex (mEC) regions have distinct neural network firing patterns to differentially support functions such as spatial memory. Accordingly, mEC layer II dorsal stellate neurons are less excitable than ventral neurons. This is partly because the densities of inhibitory conductances are higher in dorsal than ventral neurons. Here, we report that T-type Ca2+ currents increase 3-fold along the dorsal-ventral axis in mEC layer II stellate neurons, with twice as much CaV3.2 mRNA in ventral mEC compared with dorsal mEC. Long depolarizing stimuli trigger T-type Ca2+ currents, which interact with persistent Na+ currents to elevate the membrane voltage and spike firing in ventral, not dorsal, neurons. T-type Ca2+ currents themselves prolong excitatory postsynaptic potentials (EPSPs) to enhance their summation and spike coupling in ventral neurons only. These findings indicate that T-type Ca2+ currents critically influence the dorsal-ventral mEC stellate neuron excitability gradient and, thereby, mEC dorsal-ventral circuit activity.
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Affiliation(s)
| | | | - Wendy S Pratt
- Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Michele Migliore
- Institute of Biophysics, National Research Council, 90146 Palermo, Italy
| | - Annette C Dolphin
- Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Mala M Shah
- Pharmacology, School of Pharmacy, University College London, London WC1N 4AX, UK.
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16
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Crunelli V, David F, Morais TP, Lorincz ML. HCN channels and absence seizures. Neurobiol Dis 2023; 181:106107. [PMID: 37001612 DOI: 10.1016/j.nbd.2023.106107] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/20/2023] [Accepted: 03/25/2023] [Indexed: 03/31/2023] Open
Abstract
Hyperpolarization-activation cyclic nucleotide-gated (HCN) channels were for the first time implicated in absence seizures (ASs) when an abnormal Ih (the current generated by these channels) was reported in neocortical layer 5 neurons of a mouse model. Genetic studies of large cohorts of children with Childhood Absence Epilepsy (where ASs are the only clinical symptom) have identified only 3 variants in HCN1 (one of the genes that code for the 4 HCN channel isoforms, HCN1-4), with one (R590Q) mutation leading to loss-of-function. Due to the multi-faceted effects that HCN channels exert on cellular excitability and neuronal network dynamics as well as their modulation by environmental factors, it has been difficult to identify the detailed mechanism by which different HCN isoforms modulate ASs. In this review, we systematically and critically analyze evidence from established AS models and normal non-epileptic animals with area- and time-selective ablation of HCN1, HCN2 and HCN4. Notably, whereas knockout of rat HCN1 and mouse HCN2 leads to the expression of ASs, the pharmacological block of all HCN channel isoforms abolishes genetically determined ASs. These seemingly contradictory results could be reconciled by taking into account the well-known opposite effects of Ih on cellular excitability and network function. Whereas existing evidence from mouse and rat AS models indicates that pan-HCN blockers may provide a novel approach for the treatment of human ASs, the development of HCN isoform-selective drugs would greatly contribute to current research on the role for these channels in ASs generation and maintenance as well as offer new potential clinical applications.
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Affiliation(s)
- Vincenzo Crunelli
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, UK.
| | - Francois David
- Integrative Neuroscience and Cognition Center, Paris University, Paris, France
| | - Tatiana P Morais
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, Malta University, Msida, Malta
| | - Magor L Lorincz
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, UK; Department of Physiology, Szeged University, Szeged, Hungary.
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17
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Garrido JJ. Contribution of Axon Initial Segment Structure and Channels to Brain Pathology. Cells 2023; 12:cells12081210. [PMID: 37190119 DOI: 10.3390/cells12081210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 04/17/2023] [Accepted: 04/20/2023] [Indexed: 05/17/2023] Open
Abstract
Brain channelopathies are a group of neurological disorders that result from genetic mutations affecting ion channels in the brain. Ion channels are specialized proteins that play a crucial role in the electrical activity of nerve cells by controlling the flow of ions such as sodium, potassium, and calcium. When these channels are not functioning properly, they can cause a wide range of neurological symptoms such as seizures, movement disorders, and cognitive impairment. In this context, the axon initial segment (AIS) is the site of action potential initiation in most neurons. This region is characterized by a high density of voltage-gated sodium channels (VGSCs), which are responsible for the rapid depolarization that occurs when the neuron is stimulated. The AIS is also enriched in other ion channels, such as potassium channels, that play a role in shaping the action potential waveform and determining the firing frequency of the neuron. In addition to ion channels, the AIS contains a complex cytoskeletal structure that helps to anchor the channels in place and regulate their function. Therefore, alterations in this complex structure of ion channels, scaffold proteins, and specialized cytoskeleton may also cause brain channelopathies not necessarily associated with ion channel mutations. This review will focus on how the AISs structure, plasticity, and composition alterations may generate changes in action potentials and neuronal dysfunction leading to brain diseases. AIS function alterations may be the consequence of voltage-gated ion channel mutations, but also may be due to ligand-activated channels and receptors and AIS structural and membrane proteins that support the function of voltage-gated ion channels.
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Affiliation(s)
- Juan José Garrido
- Instituto Cajal, CSIC, 28002 Madrid, Spain
- Alzheimer's Disease and Other Degenerative Dementias, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), 28002 Madrid, Spain
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18
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Xing Y, Dorey A, Howorka S. Multi-Stimuli-Responsive and Mechano-Actuated Biomimetic Membrane Nanopores Self-Assembled from DNA. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2300589. [PMID: 37029712 DOI: 10.1002/adma.202300589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/31/2023] [Indexed: 06/04/2023]
Abstract
In bioinspired design, biological templates are mimicked in structure and function by highly controllable synthetic means. Of interest are static barrel-like nanopores that enable molecular transport across membranes for use in biosensing, sequencing, and biotechnology. However, biological ion channels offer additional functions such as dynamic changes of the entire pore shape between open and closed states, and triggering of dynamic processes with biochemical and physical stimuli. To better capture this complexity, this report presents multi-stimuli and mechano-responsive biomimetic nanopores which are created with DNA nanotechnology. The nanopores switch between open and closed states, whereby specific binding of DNA and protein molecules as stimuli locks the pores in the open state. Furthermore, the physical stimulus of high transmembrane voltage switches the pores into a closed state. In addition, the pore diameters are larger and more tunable than those of natural templates. These multi-stimuli-responsive and mechanically actuated nanopores mimic several aspects of complex biological channels yet offer easier control over pore size, shape and stimulus response. The designer pores are expected to be applied in biosensing and synthetic biology.
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Affiliation(s)
- Yongzheng Xing
- Department of Chemistry & Institute of Structural and Molecular Biology, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Adam Dorey
- Department of Chemistry & Institute of Structural and Molecular Biology, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Stefan Howorka
- Department of Chemistry & Institute of Structural and Molecular Biology, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
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19
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Wu J, Zhang H, Yang L, Chen Y, Li J, Yang M, Zhang X, He C, Wang X, Xu X. Syntaxin 7 modulates seizure activity in epilepsy. Neurobiol Dis 2023; 181:106118. [PMID: 37031804 DOI: 10.1016/j.nbd.2023.106118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/18/2023] [Accepted: 04/05/2023] [Indexed: 04/11/2023] Open
Abstract
The exact pathogenesis of epilepsy, one of the most common and devastating diseases of the nervous system, is not fully understood. Syntaxin7 (STX7) is a member of the SNARE superfamily, which mediates membrane fusion events in all cells. However, the role STX7 plays in epilepsy remains unclear. Therefore, this study investigates the role of STX7 in epilepsy. Our study found that the expression of STX7 was reduced in the epileptic brain and that overexpression of STX7 decreased the susceptibility to epileptic seizures and alleviated epileptic activity in a kainic acid-induced model and pentylenetetrazole-induced kindling model of epilepsy, whereas the downregulation of STX7 showed opposite effects. Whole-cell patch-clamp recordings showed that STX7 does not affect the intrinsic excitability of neurons, but rather the excitation/inhibition ratio mediated by affecting the release of presynaptic γ-aminobutyric acid neurotransmitters. Transmission electron microscopy results showed that STX7 did not affect the density of inhibitory synapses but could affect the density of inhibitory vesicles. Taken together, these results reveal a previously unknown function of STX7 in epilepsy and suggest that STX7 may serve as a novel target for epilepsy therapy.
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Affiliation(s)
- Junhong Wu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China
| | - Hui Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China; Department of Neurology, The First Hospital of Shanxi Medical University, No.85 Jiefang South Road, Taiyuan, Shanxi Province, China
| | - Liu Yang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China; Department of Neurology, The First Hospital of Shanxi Medical University, No.85 Jiefang South Road, Taiyuan, Shanxi Province, China
| | - Yuanyuan Chen
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China
| | - Jiyuan Li
- Department of Neurology, The First Hospital of Shanxi Medical University, No.85 Jiefang South Road, Taiyuan, Shanxi Province, China
| | - Min Yang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China
| | - Xiaogang Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China; Department of Neurology, Chongqing General Hospital, Chongqing Key Laboratory of Neurodegenerative Diseases, No.118, Xingguang Avenue, Liangjiang New Area, Chongqing 401147, China
| | - Changlong He
- Department of Laboratory Medicine, People's Hospital of Jiulongpo District, Chongqing 40016, China; Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
| | - Xuefeng Wang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China.
| | - Xin Xu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1 Youyi Road, Chongqing 400016, China.
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20
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Huang X, Miyata H, Wang H, Mori G, Iida-Norita R, Ikawa M, Percudani R, Chung JJ. A CUG-initiated CATSPERθ functions in the CatSper channel assembly and serves as a checkpoint for flagellar trafficking. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.17.532952. [PMID: 36993167 PMCID: PMC10055175 DOI: 10.1101/2023.03.17.532952] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Calcium signaling is critical for successful fertilization. In spermatozoa, calcium influx into the sperm flagella mediated by the sperm specific CatSper calcium channel is necessary for hyperactivated motility and male fertility. CatSper is a macromolecular complex and is repeatedly arranged in zigzag rows within four linear nanodomains along the sperm flagella. Here, we report that the Tmem249 -encoded transmembrane domain containing protein, CATSPERθ, is essential for the CatSper channel assembly during sperm tail formation. CATSPERθ facilitates the channel assembly by serving as a scaffold for a pore forming subunit CATSPER4. CATSPERθ is specifically localized at the interface of a CatSper dimer and can self-interact, suggesting its potential role in CatSper dimer formation. Male mice lacking CATSPERθ are infertile because the sperm lack the entire CatSper channel from sperm flagella, rendering sperm unable to hyperactivate, regardless of their normal expression in the testis. In contrast, genetic abrogation of any of the other CatSper transmembrane subunits results in loss of CATSPERθ protein in the spermatid cells during spermatogenesis. CATSPERθ might acts as a checkpoint for the properly assembled CatSper channel complex to traffic to sperm flagella. This study provides insights into the CatSper channel assembly and elucidates the physiological role of CATSPERθ in sperm motility and male fertility.
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Affiliation(s)
- Xiaofang Huang
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, 06510, USA
| | - Haruhiko Miyata
- Research Institute for Microbial Diseases, Osaka University, Suita 5650871, Japan
| | - Huafeng Wang
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, 06510, USA
| | - Giulia Mori
- Department of Chemistry, Life sciences, and Environmental Sustainability, University of Parma, Parma 43124, Italy
| | - Rie Iida-Norita
- Research Institute for Microbial Diseases, Osaka University, Suita 5650871, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita 5650871, Japan
| | - Riccardo Percudani
- Department of Chemistry, Life sciences, and Environmental Sustainability, University of Parma, Parma 43124, Italy
| | - Jean-Ju Chung
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, 06510, USA
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, Yale University, New Haven, CT, 06510
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21
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Deng S, Zhang E, Tao J, Zhao Y, Huo W, Guo H, Zheng B, Mu X, Yuan K, Deng X, Shen H, Rong H, Ma Y, Bian W. Graphene quantum dots (GQDs) induce thigmotactic effect in zebrafish larvae via modulating key genes and metabolites related to synaptic plasticity. Toxicology 2023; 487:153462. [PMID: 36805088 DOI: 10.1016/j.tox.2023.153462] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/06/2023] [Accepted: 02/17/2023] [Indexed: 02/19/2023]
Abstract
Graphene quantum dots (GQDs) recently gain much attention for its medicinal values in treating diseases such as neurodegeneration and inflammations. However, owing to the high permeability of GQDs across the blood-brain barrier, whether its retention in the central nervous system (CNS) perturbs neurobehaviors remains less reported. In the study, the locomotion of zebrafish larvae (Danio rerio) was fully evaluated when administrated by two GQDs in a concentration gradient, respectively as reduced-GQDs (R-GQDs): 150, 300, 600, 1200, and 2400 g/L, and graphene oxide QDs (GOQDs): 60, 120, 240, 480, and 960 g/L. After exposure, the larvae were kept for locomotion analysis within one week's depuration. Substantial data showed that the basal locomotor activity of zebrafish larvae was not significantly changed by both two GQDs at low concentrations while weakened greatly with the increase of concentrations, and the total ATP levels of zebrafish larvae were also found to decrease significantly when exposed to the highest concentrations of GQDs. Next, the thigmotactic effect was observed to be remarkably induced in larvae by both two GQDs at any concentrations during exposure, and remained strong in larvae treated by high concentrations of R-GQDs after 7 days' depuration. To be noted, we found that GQDs affected the synaptic plasticity via downregulating the mRNA levels of NMDA and AMPA receptor family members as well as the total glutamine levels in zebrafish larvae. Together, our study presented robust data underlying the locomotor abnormalities aroused by GQDs in zebrafish larvae and indicated the potential adverse effects of GQDs on synaptic plasticity.
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Affiliation(s)
- Shun Deng
- Sichuan Provincial Orthopedic Hospital, Chengdu 610041, China.
| | - Enming Zhang
- School of sports medicine and physical therapy, Beijing Sport University, Beijing 100084, China
| | - Junyu Tao
- School of sports medicine and health, Chengdu Sport University, Chengdu 610041, China
| | - Yunyang Zhao
- Scientific Research Center, Wenzhou Medical University, Wenzhou 325035, China
| | - Wenbo Huo
- Chongqing institute of green and intelligent technology, Chinese Academy of Science, Chongqing 400714, China
| | - Hao Guo
- School of sports medicine and physical therapy, Beijing Sport University, Beijing 100084, China
| | - Bingxin Zheng
- Sichuan Provincial Orthopedic Hospital, Chengdu 610041, China
| | - Xiaoyuan Mu
- Sichuan Provincial Orthopedic Hospital, Chengdu 610041, China
| | - Kezhu Yuan
- Sichuan Provincial Orthopedic Hospital, Chengdu 610041, China
| | - Xuangen Deng
- Sichuan Provincial Orthopedic Hospital, Chengdu 610041, China
| | - Hai Shen
- Sichuan Provincial Orthopedic Hospital, Chengdu 610041, China
| | - Haibo Rong
- Sichuan Provincial Orthopedic Hospital, Chengdu 610041, China
| | - Yanbo Ma
- Chongqing institute of green and intelligent technology, Chinese Academy of Science, Chongqing 400714, China
| | - Wanping Bian
- Chongqing institute of green and intelligent technology, Chinese Academy of Science, Chongqing 400714, China
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22
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Nsasra E, Peretz G, Orr I, Yifrach O. Regulating Shaker Kv channel clustering by hetero-oligomerization. Front Mol Biosci 2023; 9:1050942. [PMID: 36699695 PMCID: PMC9868669 DOI: 10.3389/fmolb.2022.1050942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/19/2022] [Indexed: 01/11/2023] Open
Abstract
Scaffold protein-mediated voltage-dependent ion channel clustering at unique membrane sites, such as nodes of Ranvier or the post-synaptic density plays an important role in determining action potential properties and information coding. Yet, the mechanism(s) by which scaffold protein-ion channel interactions lead to channel clustering and how cluster ion channel density is regulated are mostly unknown. This molecular-cellular gap in understanding channel clustering can be bridged in the case of the prototypical Shaker voltage-activated potassium channel (Kv), as the mechanism underlying the interaction of this channel with its PSD-95 scaffold protein partner is known. According to this mechanism, changes in the length of the intrinsically disordered channel C-terminal chain, brought about by alternative splicing to yield the short A and long B chain subunit variants, dictate affinity to PSD-95 and further controls cluster homo-tetrameric Kv channel density. These results raise the hypothesis that heteromeric subunit assembly serves as a means to regulate Kv channel clustering. Since both clustering variants are expressed in similar fly tissues, it is reasonable to assume that hetero-tetrameric channels carrying different numbers of high- (A) and low-affinity (B) subunits could assemble, thereby giving rise to distinct cluster Kv channel densities. Here, we tested this hypothesis using high-resolution microscopy, combined with quantitative clustering analysis. Our results reveal that the A and B clustering variants can indeed assemble to form heteromeric channels and that controlling the number of the high-affinity A subunits within the hetero-oligomer modulates cluster Kv channel density. The implications of these findings for electrical signaling are discussed.
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23
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Zhao K, Li Y, Yang X, Zhou L. The Impact of Altered HCN1 Expression on Brain Function and Its Relationship with Epileptogenesis. Curr Neuropharmacol 2023; 21:2070-2078. [PMID: 37366350 PMCID: PMC10556362 DOI: 10.2174/1570159x21666230214110333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/13/2022] [Accepted: 12/06/2022] [Indexed: 03/08/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated cation channel 1 (HCN1) is predominantly expressed in neurons from the neocortex and hippocampus, two important regions related to epilepsy. Both animal models for epilepsy and epileptic patients show decreased HCN1 expression and HCN1-mediated Ih current. It has been shown in neuroelectrophysiological experiments that a decreased Ih current can increase neuronal excitability. However, some studies have shown that blocking the Ih current in vivo can exert antiepileptic effects. This paradox raises an important question regarding the causal relationship between HCN1 alteration and epileptogenesis, which to date has not been elucidated. In this review, we summarize the literature related to HCN1 and epilepsy, aiming to find a possible explanation for this paradox, and explore the correlation between HCN1 and the mechanism of epileptogenesis. We analyze the alterations in the expression and distribution of HCN1 and the corresponding impact on brain function in epilepsy. In addition, we also discuss the effect of blocking Ih on epilepsy symptoms. Addressing these issues will help to inspire new strategies to explore the relationship between HCN1 and epileptogenesis, and ultimately promote the development of new targets for epilepsy therapy.
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Affiliation(s)
- Ke Zhao
- Department of Neurology, The Seventh Affliated Hospital of Sun Yet-sen University, No. 628, Zhenyuan Road, Xinhu Street, Guangming District, Shenzhen, China
| | - Yinchao Li
- Department of Neurology, The Seventh Affliated Hospital of Sun Yet-sen University, No. 628, Zhenyuan Road, Xinhu Street, Guangming District, Shenzhen, China
| | - Xiaofeng Yang
- Guangzhou Laboratory, Guangzhou, No. 9 XingDaoHuanBei Road, Guangzhou International Bio Island, Guangzhou 510005, Guangdong Province, China
| | - Liemin Zhou
- Department of Neurology, The Seventh Affliated Hospital of Sun Yet-sen University, No. 628, Zhenyuan Road, Xinhu Street, Guangming District, Shenzhen, China
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24
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Rathour RK, Kaphzan H. Synergies between synaptic and HCN channel plasticity dictates firing rate homeostasis and mutual information transfer in hippocampal model neuron. Front Cell Neurosci 2023; 17:1096823. [PMID: 37020846 PMCID: PMC10067771 DOI: 10.3389/fncel.2023.1096823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 03/02/2023] [Indexed: 04/07/2023] Open
Abstract
Homeostasis is a precondition for any physiological system of any living organism. Nonetheless, models of learning and memory that are based on processes of synaptic plasticity are unstable by nature according to Hebbian rules, and it is not fully clear how homeostasis is maintained during these processes. This is where theoretical and computational frameworks can help in gaining a deeper understanding of the various cellular processes that enable homeostasis in the face of plasticity. A previous simplistic single compartmental model with a single synapse showed that maintaining input/output response homeostasis and stable synaptic learning could be enabled by introducing a linear relationship between synaptic plasticity and HCN conductance plasticity. In this study, we aimed to examine whether this approach could be extended to a more morphologically realistic model that entails multiple synapses and gradients of various VGICs. In doing so, we found that a linear relationship between synaptic plasticity and HCN conductance plasticity was able to maintain input/output response homeostasis in our morphologically realistic model, where the slope of the linear relationship was dependent on baseline HCN conductance and synaptic permeability values. An increase in either baseline HCN conductance or synaptic permeability value led to a decrease in the slope of the linear relationship. We further show that in striking contrast to the single compartment model, here linear relationship was insufficient in maintaining stable synaptic learning despite maintaining input/output response homeostasis. Additionally, we showed that homeostasis of input/output response profiles was at the expense of decreasing the mutual information transfer due to the increase in noise entropy, which could not be fully rescued by optimizing the linear relationship between synaptic and HCN conductance plasticity. Finally, we generated a place cell model based on theta oscillations and show that synaptic plasticity disrupts place cell activity. Whereas synaptic plasticity accompanied by HCN conductance plasticity through linear relationship maintains the stability of place cell activity. Our study establishes potential differences between a single compartmental model and a morphologically realistic model.
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25
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Abad-Rodríguez J, Brocca ME, Higuero AM. Glycans and Carbohydrate-Binding/Transforming Proteins in Axon Physiology. ADVANCES IN NEUROBIOLOGY 2023; 29:185-217. [PMID: 36255676 DOI: 10.1007/978-3-031-12390-0_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The mature nervous system relies on the polarized morphology of neurons for a directed flow of information. These highly polarized cells use their somatodendritic domain to receive and integrate input signals while the axon is responsible for the propagation and transmission of the output signal. However, the axon must perform different functions throughout development before being fully functional for the transmission of information in the form of electrical signals. During the development of the nervous system, axons perform environmental sensing functions, which allow them to navigate through other regions until a final target is reached. Some axons must also establish a regulated contact with other cells before reaching maturity, such as with myelinating glial cells in the case of myelinated axons. Mature axons must then acquire the structural and functional characteristics that allow them to perform their role as part of the information processing and transmitting unit that is the neuron. Finally, in the event of an injury to the nervous system, damaged axons must try to reacquire some of their immature characteristics in a regeneration attempt, which is mostly successful in the PNS but fails in the CNS. Throughout all these steps, glycans perform functions of the outermost importance. Glycans expressed by the axon, as well as by their surrounding environment and contacting cells, encode key information, which is fine-tuned by glycan modifying enzymes and decoded by glycan binding proteins so that the development, guidance, myelination, and electrical transmission functions can be reliably performed. In this chapter, we will provide illustrative examples of how glycans and their binding/transforming proteins code and decode instructive information necessary for fundamental processes in axon physiology.
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Affiliation(s)
- José Abad-Rodríguez
- Membrane Biology and Axonal Repair Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain.
| | - María Elvira Brocca
- Membrane Biology and Axonal Repair Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain
| | - Alonso Miguel Higuero
- Membrane Biology and Axonal Repair Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain
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26
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Stevens SR, Rasband MN. Pleiotropic Ankyrins: Scaffolds for Ion Channels and Transporters. Channels (Austin) 2022; 16:216-229. [PMID: 36082411 PMCID: PMC9467607 DOI: 10.1080/19336950.2022.2120467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The ankyrin proteins (Ankyrin-R, Ankyrin-B, and Ankyrin-G) are a family of scaffolding, or membrane adaptor proteins necessary for the regulation and targeting of several types of ion channels and membrane transporters throughout the body. These include voltage-gated sodium, potassium, and calcium channels in the nervous system, heart, lungs, and muscle. At these sites, ankyrins recruit ion channels, and other membrane proteins, to specific subcellular domains, which are then stabilized through ankyrin's interaction with the submembranous spectrin-based cytoskeleton. Several recent studies have expanded our understanding of both ankyrin expression and their ion channel binding partners. This review provides an updated overview of ankyrin proteins and their known channel and transporter interactions. We further discuss several potential avenues of future research that would expand our understanding of these important organizational proteins.
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Affiliation(s)
- Sharon R. Stevens
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Matthew N. Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA,CONTACT Matthew N. Rasband Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX77030, USA
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27
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Horaruang W, Klejchová M, Carroll W, Silva-Alvim FAL, Waghmare S, Papanatsiou M, Amtmann A, Hills A, Alvim JC, Blatt MR, Zhang B. Engineering a K + channel 'sensory antenna' enhances stomatal kinetics, water use efficiency and photosynthesis. NATURE PLANTS 2022; 8:1262-1274. [PMID: 36266492 DOI: 10.1038/s41477-022-01255-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 09/12/2022] [Indexed: 06/16/2023]
Abstract
Stomata of plant leaves open to enable CO2 entry for photosynthesis and close to reduce water loss via transpiration. Compared with photosynthesis, stomata respond slowly to fluctuating light, reducing assimilation and water use efficiency. Efficiency gains are possible without a cost to photosynthesis if stomatal kinetics can be accelerated. Here we show that clustering of the GORK channel, which mediates K+ efflux for stomatal closure in the model plant Arabidopsis, arises from binding between the channel voltage sensors, creating an extended 'sensory antenna' for channel gating. Mutants altered in clustering affect channel gating to facilitate K+ flux, accelerate stomatal movements and reduce water use without a loss in biomass. Our findings identify the mechanism coupling channel clustering with gating, and they demonstrate the potential for engineering of ion channels native to the guard cell to enhance stomatal kinetics and improve water use efficiency without a cost in carbon fixation.
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Affiliation(s)
- Wijitra Horaruang
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
- Faculty of Science and Arts, Burapha University, Chanthaburi Campus, Chanthaburi, Thailand
| | - Martina Klejchová
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
| | - William Carroll
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
| | | | - Sakharam Waghmare
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
| | - Maria Papanatsiou
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
| | - Anna Amtmann
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
| | - Adrian Hills
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
| | - Jonas Chaves Alvim
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK.
| | - Ben Zhang
- School of Life Sciences, Shanxi University, Taiyuan City, China
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28
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Nandi A, Chartrand T, Van Geit W, Buchin A, Yao Z, Lee SY, Wei Y, Kalmbach B, Lee B, Lein E, Berg J, Sümbül U, Koch C, Tasic B, Anastassiou CA. Single-neuron models linking electrophysiology, morphology, and transcriptomics across cortical cell types. Cell Rep 2022; 40:111176. [PMID: 35947954 PMCID: PMC9793758 DOI: 10.1016/j.celrep.2022.111176] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 01/28/2022] [Accepted: 07/18/2022] [Indexed: 12/30/2022] Open
Abstract
Which cell types constitute brain circuits is a fundamental question, but establishing the correspondence across cellular data modalities is challenging. Bio-realistic models allow probing cause-and-effect and linking seemingly disparate modalities. Here, we introduce a computational optimization workflow to generate 9,200 single-neuron models with active conductances. These models are based on 230 in vitro electrophysiological experiments followed by morphological reconstruction from the mouse visual cortex. We show that, in contrast to current belief, the generated models are robust representations of individual experiments and cortical cell types as defined via cellular electrophysiology or transcriptomics. Next, we show that differences in specific conductances predicted from the models reflect differences in gene expression supported by single-cell transcriptomics. The differences in model conductances, in turn, explain electrophysiological differences observed between the cortical subclasses. Our computational effort reconciles single-cell modalities that define cell types and enables causal relationships to be examined.
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Affiliation(s)
- Anirban Nandi
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Thomas Chartrand
- Allen Institute for Brain Science, Seattle, WA 98109, USA,These authors contributed equally
| | - Werner Van Geit
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Campus Biotech, Geneva 1202, Switzerland,These authors contributed equally
| | - Anatoly Buchin
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Zizhen Yao
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Soo Yeun Lee
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Yina Wei
- Allen Institute for Brain Science, Seattle, WA 98109, USA,Zhejiang Lab, Hangzhou City, Zhejiang Province 311121, China
| | - Brian Kalmbach
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Brian Lee
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Ed Lein
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Jim Berg
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Uygar Sümbül
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Christof Koch
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Bosiljka Tasic
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Costas A. Anastassiou
- Allen Institute for Brain Science, Seattle, WA 98109, USA,Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA,Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA,Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA,Lead contact,Correspondence:
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29
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Rathour RK, Kaphzan H. Voltage-Gated Ion Channels and the Variability in Information Transfer. Front Cell Neurosci 2022; 16:906313. [PMID: 35936503 PMCID: PMC9352938 DOI: 10.3389/fncel.2022.906313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/24/2022] [Indexed: 11/13/2022] Open
Abstract
The prerequisites for neurons to function within a circuit and be able to contain and transfer information efficiently and reliably are that they need to be homeostatically stable and fire within a reasonable range, characteristics that are governed, among others, by voltage-gated ion channels (VGICs). Nonetheless, neurons entail large variability in the expression levels of VGICs and their corresponding intrinsic properties, but the role of this variability in information transfer is not fully known. In this study, we aimed to investigate how this variability of VGICs affects information transfer. For this, we used a previously derived population of neuronal model neurons, each with the variable expression of five types of VGICs, fast Na+, delayed rectifier K+, A-type K+, T-type Ca++, and HCN channels. These analyses showed that the model neurons displayed variability in mutual information transfer, measured as the capability of neurons to successfully encode incoming synaptic information in output firing frequencies. Likewise, variability in the expression of VGICs caused variability in EPSPs and IPSPs amplitudes, reflected in the variability of output firing frequencies. Finally, using the virtual knockout methodology, we show that among the ion channels tested, the A-type K+ channel is the major regulator of information processing and transfer.
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30
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Pharmacological Screening of Venoms from Five Brazilian Micrurus Species on Different Ion Channels. Int J Mol Sci 2022; 23:ijms23147714. [PMID: 35887062 PMCID: PMC9318628 DOI: 10.3390/ijms23147714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/05/2022] [Accepted: 07/07/2022] [Indexed: 12/05/2022] Open
Abstract
Coral snake venoms from the Micrurus genus are a natural library of components with multiple targets, yet are poorly explored. In Brazil, 34 Micrurus species are currently described, and just a few have been investigated for their venom activities. Micrurus venoms are composed mainly of phospholipases A2 and three-finger toxins, which are responsible for neuromuscular blockade—the main envenomation outcome in humans. Beyond these two major toxin families, minor components are also important for the global venom activity, including Kunitz-peptides, serine proteases, 5′ nucleotidases, among others. In the present study, we used the two-microelectrode voltage clamp technique to explore the crude venom activities of five different Micrurus species from the south and southeast of Brazil: M. altirostris, M. corallinus, M. frontalis, M. carvalhoi and M. decoratus. All five venoms induced full inhibition of the muscle-type α1β1δε nAChR with different levels of reversibility. We found M. altirostris and M. frontalis venoms acting as partial inhibitors of the neuronal-type α7 nAChR with an interesting subsequent potentiation after one washout. We discovered that M. altirostris and M. corallinus venoms modulate the α1β2 GABAAR. Interestingly, the screening on KV1.3 showed that all five Micrurus venoms act as inhibitors, being totally reversible after the washout. Since this activity seems to be conserved among different species, we hypothesized that the Micrurus venoms may rely on potassium channel inhibitory activity as an important feature of their envenomation strategy. Finally, tests on NaV1.2 and NaV1.4 showed that these channels do not seem to be targeted by Micrurus venoms. In summary, the venoms tested are multifunctional, each of them acting on at least two different types of targets.
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31
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Liu Y, Lu Y, Tang Z, Cao Y, Huang D, Wu F, Zhang Y, Li C, Chen G, Wang Q. Single-particle fluorescence tracking combined with TrackMate assay reveals highly heterogeneous and discontinuous lysosomal transport in freely orientated axons. Biotechnol J 2022; 17:e2200006. [PMID: 35765726 DOI: 10.1002/biot.202200006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 06/11/2022] [Accepted: 06/22/2022] [Indexed: 11/12/2022]
Abstract
Axonal transport plays a significant role in the establishment of neuronal polarity, axon growth, and synapse formation during neuronal development. The axon of a naturally growing neuron is a highly complex and multifurcated structure with a large number of bends and branches. Nowadays, the study of dynamic axonal transport in morphologically complex neurons is greatly limited by the technological barrier. Here, a sparse gene transfection strategy was developed to locate fluorescent mCherry in the lysosome of primary neurons, thus enabling us to track the lysosome-based axonal transport with a single-particle resolution. Thereby, several axonal transport models were observed, including the forward or backward transport model, stop-and-go model, repeated back-and-forth transport model, and cross-branch transport model. Then, the accurate single-particle velocity quantification by TrackMate revealed a highly heterogeneous and discontinuous transportation process of lysosome-based axonal transport in freely orientated axons. And, multiple physical factors, such as the axonal structure and the size of particles, were disclosed to affect the velocity of particle transporting in freely orientated axons. The combined single-particle fluorescence tracking and TrackMate assay can be served as a facile tool for evaluating axonal transport in neuronal development and axonal transport-related diseases.
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Affiliation(s)
- Yongyang Liu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Yaxin Lu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Zhiyong Tang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China
| | - Yuheng Cao
- CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China.,School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Dehua Huang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China
| | - Feng Wu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China
| | - Yejun Zhang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China
| | - Chunyan Li
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Guangcun Chen
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Qiangbin Wang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China.,School of Physical Science and Technology, ShanghaiTech University, Shanghai, China.,College of Materials Sciences and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, China
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32
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Zheng H, Yan X, Li G, Lin H, Deng S, Zhuang W, Yao F, Lu Y, Xia X, Yuan H, Jin L, Yan Z. Proactive functional classification of all possible missense single-nucleotide variants in KCNQ4. Genome Res 2022; 32:gr.276562.122. [PMID: 35760561 PMCID: PMC9435748 DOI: 10.1101/gr.276562.122] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 06/21/2022] [Indexed: 02/05/2023]
Abstract
Clinical exome sequencing has yielded extensive disease-related missense single-nucleotide variants (SNVs) of uncertain significance, leading to diagnostic uncertainty. KCNQ4 is one of the most commonly responsible genes for autosomal dominant nonsyndromic hearing loss. According to the gnomAD cohort, approximately one in 100 people harbors missense variants in KCNQ4 (missense variants with minor allele frequency > 0.1% were excluded), but most are of unknown consequence. To prospectively characterize the function of all 4085 possible missense SNVs of human KCNQ4, we recorded the whole-cell currents using the patch-clamp technique and categorized 1068 missense SNVs as loss of function, as well as 728 loss-of-function SNVs located in the transmembrane domains. Further, to mimic the heterozygous condition in Deafness nonsyndromic autosomal dominant 2 (DFNA2) patients caused by KCNQ4 variants, we coexpressed loss-of-function variants with wild-type KCNQ4 and found 516 variants showed impaired or only partially rescued heterogeneous channel function. Overall, our functional classification is highly concordant with the auditory phenotypes in Kcnq4 mutant mice and the assessments of pathogenicity in clinical variant interpretations. Taken together, our results provide strong functional evidence to support the pathogenicity classification of newly discovered KCNQ4 missense variants in clinical genetic testing.
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Affiliation(s)
- Honglan Zheng
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200438, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Xinhao Yan
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200438, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Guanluan Li
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200438, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Hengwei Lin
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200438, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Siqi Deng
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Wenhui Zhuang
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200438, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Fuqiang Yao
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200438, China
| | - Yu Lu
- Institute of Rare Diseases, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Xin Xia
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200438, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Huijun Yuan
- Institute of Rare Diseases, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Li Jin
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Zhiqiang Yan
- Human Phenome Institute, School of Life Sciences, Fudan University, Shanghai 200438, China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200438, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China
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33
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Schürmann F, Courcol JD, Ramaswamy S. Computational Concepts for Reconstructing and Simulating Brain Tissue. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1359:237-259. [PMID: 35471542 DOI: 10.1007/978-3-030-89439-9_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
It has previously been shown that it is possible to derive a new class of biophysically detailed brain tissue models when one computationally analyzes and exploits the interdependencies or the multi-modal and multi-scale organization of the brain. These reconstructions, sometimes referred to as digital twins, enable a spectrum of scientific investigations. Building such models has become possible because of increase in quantitative data but also advances in computational capabilities, algorithmic and methodological innovations. This chapter presents the computational science concepts that provide the foundation to the data-driven approach to reconstructing and simulating brain tissue as developed by the EPFL Blue Brain Project, which was originally applied to neocortical microcircuitry and extended to other brain regions. Accordingly, the chapter covers aspects such as a knowledge graph-based data organization and the importance of the concept of a dataset release. We illustrate algorithmic advances in finding suitable parameters for electrical models of neurons or how spatial constraints can be exploited for predicting synaptic connections. Furthermore, we explain how in silico experimentation with such models necessitates specific addressing schemes or requires strategies for an efficient simulation. The entire data-driven approach relies on the systematic validation of the model. We conclude by discussing complementary strategies that not only enable judging the fidelity of the model but also form the basis for its systematic refinements.
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Affiliation(s)
- Felix Schürmann
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Geneva, Switzerland.
| | - Jean-Denis Courcol
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Srikanth Ramaswamy
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL), Geneva, Switzerland
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Tian T, Quintana-Urzainqui I, Kozić Z, Pratt T, Price DJ. Pax6 loss alters the morphological and electrophysiological development of mouse prethalamic neurons. Development 2022; 149:274738. [PMID: 35224626 PMCID: PMC8977098 DOI: 10.1242/dev.200052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 02/16/2022] [Indexed: 12/02/2022]
Abstract
Pax6 is a well-known regulator of early neuroepithelial progenitor development. Its constitutive loss has a particularly strong effect on the developing prethalamus, causing it to become extremely hypoplastic. To overcome this difficulty in studying the long-term consequences of Pax6 loss for prethalamic development, we used conditional mutagenesis to delete Pax6 at the onset of neurogenesis and studied the developmental potential of the mutant prethalamic neurons in vitro. We found that Pax6 loss affected their rates of neurite elongation, the location and length of their axon initial segments, and their electrophysiological properties. Our results broaden our understanding of the long-term consequences of Pax6 deletion in the developing mouse forebrain, suggesting that it can have cell-autonomous effects on the structural and functional development of some neurons. Summary: Pax6 impacts neurite extension, axon initial segment properties and the ability to fire normal action potentials in maturing neurons, revealing actions extending beyond those previously characterised in progenitors.
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Affiliation(s)
- Tian Tian
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Idoia Quintana-Urzainqui
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69012 Heidelberg, Germany
| | - Zrinko Kozić
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Thomas Pratt
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - David J. Price
- Simons Initiative for the Developing Brain, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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35
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Genetic paroxysmal neurological disorders featuring episodic ataxia and epilepsy. Eur J Med Genet 2022; 65:104450. [DOI: 10.1016/j.ejmg.2022.104450] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 02/02/2022] [Accepted: 02/06/2022] [Indexed: 01/25/2023]
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36
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Dixon RE, Navedo MF, Binder MD, Santana LF. Mechanisms and Physiological Implications of Cooperative Gating of Ion Channels Clusters. Physiol Rev 2021; 102:1159-1210. [PMID: 34927454 DOI: 10.1152/physrev.00022.2021] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ion channels play a central role in the regulation of nearly every cellular process. Dating back to the classic 1952 Hodgkin-Huxley model of the generation of the action potential, ion channels have always been thought of as independent agents. A myriad of recent experimental findings exploiting advances in electrophysiology, structural biology, and imaging techniques, however, have posed a serious challenge to this long-held axiom as several classes of ion channels appear to open and close in a coordinated, cooperative manner. Ion channel cooperativity ranges from variable-sized oligomeric cooperative gating in voltage-gated, dihydropyridine-sensitive Cav1.2 and Cav1.3 channels to obligatory dimeric assembly and gating of voltage-gated Nav1.5 channels. Potassium channels, transient receptor potential channels, hyperpolarization cyclic nucleotide-activated channels, ryanodine receptors (RyRs), and inositol trisphosphate receptors (IP3Rs) have also been shown to gate cooperatively. The implications of cooperative gating of these ion channels range from fine tuning excitation-contraction coupling in muscle cells to regulating cardiac function and vascular tone, to modulation of action potential and conduction velocity in neurons and cardiac cells, and to control of pace-making activity in the heart. In this review, we discuss the mechanisms leading to cooperative gating of ion channels, their physiological consequences and how alterations in cooperative gating of ion channels may induce a range of clinically significant pathologies.
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Affiliation(s)
- Rose Ellen Dixon
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, CA, United States
| | - Marc D Binder
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
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37
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Yamano R, Miyazaki H, Nukina N. The diffuse distribution of Nav1.2 on mid-axonal regions is a marker for unmyelinated fibers in the central nervous system. Neurosci Res 2021; 177:145-150. [PMID: 34808247 DOI: 10.1016/j.neures.2021.11.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 11/25/2022]
Abstract
Unmyelinated fibers in the central nervous system are known to exist in hippocampal mossy fibers, cerebellar parallel fibers and striatal projection fibers. Previously, we and others reported diffuse distribution of Nav1.2, a voltage-gated sodium channel α-subunit encoded by the SCN2A gene, on unmyelinated striatal projection fibers. Mutations in the SCN2A gene are associated with epilepsies and autism. In this study, we investigated the distribution of Nav1.2 on the unmyelinated fibers in the corpus callosum and stria terminalis by immunohistochemistry and immunoelectron microscopy analysis, suggesting that diffuse localization of Nav1.2 on mid-axonal regions can be a useful marker for unmyelinated fibers.
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Affiliation(s)
- Risa Yamano
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Miyakodanitatara, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Haruko Miyazaki
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Miyakodanitatara, Kyotanabe-shi, Kyoto, 610-0394, Japan.
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Miyakodanitatara, Kyotanabe-shi, Kyoto, 610-0394, Japan.
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38
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Autism-associated mutations in K V7 channels induce gating pore current. Proc Natl Acad Sci U S A 2021; 118:2112666118. [PMID: 34728568 PMCID: PMC8609342 DOI: 10.1073/pnas.2112666118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2021] [Indexed: 12/12/2022] Open
Abstract
Autism spectrum disorder (ASD) adversely impacts >1% of children in the United States, causing social interaction deficits, repetitive behaviors, and communication disorders. Genetic analysis of ASD has advanced dramatically through genome sequencing, which has identified >500 genes with mutations in ASD. Mutations that alter arginine gating charges in the voltage sensor of the voltage-gated potassium (KV) channel KV7 (KCNQ) are among those frequently associated with ASD. We hypothesized that these gating charge mutations would induce gating pore current (also termed ω-current) by causing an ionic leak through the mutant voltage sensor. Unexpectedly, we found that wild-type KV7 conducts outward gating pore current through its native voltage sensor at positive membrane potentials, owing to a glutamine in the third gating charge position. In bacterial and human KV7 channels, gating charge mutations at the R1 and R2 positions cause inward gating pore current through the resting voltage sensor at negative membrane potentials, whereas mutation at R4 causes outward gating pore current through the activated voltage sensor at positive potentials. Remarkably, expression of the KV7.3/R2C ASD-associated mutation in vivo in midbrain dopamine neurons of mice disrupts action potential generation and repetitive firing. Overall, our results reveal native and mutant gating pore current in KV7 channels and implicate altered control of action potential generation by gating pore current through mutant KV7 channels as a potential pathogenic mechanism in autism.
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39
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Abd El-Hameed AM, Abuelsaad ASA, Khalil A. Bee venom acupuncture therapy ameliorates neuroinflammatory alterations in a pilocarpine-induced epilepticus model. Metab Brain Dis 2021; 36:2047-2058. [PMID: 34138441 DOI: 10.1007/s11011-021-00766-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 06/06/2021] [Indexed: 11/25/2022]
Abstract
Bee venom (BV) is applied in different traditional medicinal therapies and is used worldwide to prevent and treat many acute and chronic diseases. Epilepsy has various neurological effects, e.g., epileptogenic insults; thus, it is considered a life-threatening condition. Seizures and their effects add to the burden of epilepsy because they can have health effects including residual disability and even premature mortality. The use of antiinflammatory drugs to treat epilepsy is controversial; therefore, the alternative nonchemical apitherapy benefits of BV were evaluated in the present study by assessing neuroinflammatory changes in a pilocarpine-induced epilepticus model. Levels of electrolytes, neurotransmitters, and mRNA expression for some gate channels were determined. Moreover, ELISA assays were conducted to detect pro- and anti-inflammatory cytokines, whereas RT-PCR was performed to assess mRNA expression of Foxp3 and CTLA-4. BV ameliorated the interruption in electrolytes and ions through voltage- and ligand-gated ion channels, and it limited neuronal excitability via rapid repolarization of action potentials. In addition, BV inhibited the high expression of proinflammatory cytokines. Acupuncture with BV was effective in preventing some of the deleterious consequences of epileptogenesis associated with high levels of glutamate and DOPA in the hippocampus. BV ameliorates changes in the expression of voltage-gated channels, rebalances blood electrolytes and neurotransmitters, and modulates the levels of pro- and anti-inflammatory cytokines. Thus, BV could reduce the progression of epileptogenesis as a cotherapy with other antiepileptic drugs.
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Affiliation(s)
| | - Abdelaziz S A Abuelsaad
- Immunology Division, Department of Zoology, Faculty of Science, Beni-Suef University, 62511, Beni-Suef, Egypt.
| | - Abdelwahab Khalil
- Medical Entomology Division, Department of Zoology, Faculty of Science, Beni-Suef University, Beni-Suef, 62521, Egypt
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40
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Developmental HCN channelopathy results in decreased neural progenitor proliferation and microcephaly in mice. Proc Natl Acad Sci U S A 2021; 118:2009393118. [PMID: 34429357 DOI: 10.1073/pnas.2009393118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The development of the cerebral cortex relies on the controlled division of neural stem and progenitor cells. The requirement for precise spatiotemporal control of proliferation and cell fate places a high demand on the cell division machinery, and defective cell division can cause microcephaly and other brain malformations. Cell-extrinsic and -intrinsic factors govern the capacity of cortical progenitors to produce large numbers of neurons and glia within a short developmental time window. In particular, ion channels shape the intrinsic biophysical properties of precursor cells and neurons and control their membrane potential throughout the cell cycle. We found that hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channel subunits are expressed in mouse, rat, and human neural progenitors. Loss of HCN channel function in rat neural stem cells impaired their proliferation by affecting the cell-cycle progression, causing G1 accumulation and dysregulation of genes associated with human microcephaly. Transgene-mediated, dominant-negative loss of HCN channel function in the embryonic mouse telencephalon resulted in pronounced microcephaly. Together, our findings suggest a role for HCN channel subunits as a part of a general mechanism influencing cortical development in mammals.
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41
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Oulé M, Atucha E, Wells TM, Macharadze T, Sauvage MM, Kreutz MR, Lopez-Rojas J. Dendritic Kv4.2 potassium channels selectively mediate spatial pattern separation in the dentate gyrus. iScience 2021; 24:102876. [PMID: 34386734 PMCID: PMC8346659 DOI: 10.1016/j.isci.2021.102876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/22/2021] [Accepted: 07/14/2021] [Indexed: 11/23/2022] Open
Abstract
The capacity to distinguish comparable experiences is fundamental for the recall of similar memories and has been proposed to require pattern separation in the dentate gyrus (DG). However, the cellular mechanisms by which mature granule cells (GCs) of the DG accomplish this function are poorly characterized. Here, we show that Kv4.2 channels selectively modulate the excitability of medial dendrites of dentate GCs. These dendrites are targeted by the medial entorhinal cortex, the main source of spatial inputs to the DG. Accordingly, we found that the spatial pattern separation capability of animals lacking the Kv4.2 channel is significantly impaired. This points to the role of intrinsic excitability in supporting the mnemonic function of the dentate and to the Kv4.2 channel as a candidate substrate promoting spatial pattern separation.
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Affiliation(s)
- Marie Oulé
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Erika Atucha
- Functional Architecture of Memory Department, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Tenyse M. Wells
- Functional Architecture of Memory Department, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Tamar Macharadze
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
- Department of Anesthesiology and Intensive Care Medicine, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | - Magdalena M. Sauvage
- Functional Architecture of Memory Department, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
- Otto von Guericke University, Medical Faculty, Functional Neuroplasticity Department, 39120, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany
| | - Michael R. Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany
- Leibniz Group 'Dendritic Organelles and Synaptic Function', University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology (ZMNH), 20251 Hamburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Jeffrey Lopez-Rojas
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany
- Department of Neuroscience, The Kavli Institute for Brain Science, Mortimer B. Zuckerman Mind Brain Behavior Institute, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10027, USA
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42
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Abstract
Calcium (Ca2+) is a unique mineral that serves as both a nutrient and a signal in all eukaryotes. To maintain Ca2+ homeostasis for both nutrition and signaling purposes, the toolkit for Ca2+ transport has expanded across kingdoms of eukaryotes to encode specific Ca2+ signals referred to as Ca2+ signatures. In parallel, a large array of Ca2+-binding proteins has evolved as specific sensors to decode Ca2+ signatures. By comparing these coding and decoding mechanisms in fungi, animals, and plants, both unified and divergent themes have emerged, and the underlying complexity will challenge researchers for years to come. Considering the scale and breadth of the subject, instead of a literature survey, in this review we focus on a conceptual framework that aims to introduce to readers to the principles and mechanisms of Ca2+ signaling. We finish with several examples of Ca2+-signaling pathways, including polarized cell growth, immunity and symbiosis, and systemic signaling, to piece together specific coding and decoding mechanisms in plants versus animals. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Sheng Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA;
| | - Chao Wang
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA;
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43
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Platholi J, Hemmings HC. Effects of general anesthetics on synaptic transmission and plasticity. Curr Neuropharmacol 2021; 20:27-54. [PMID: 34344292 PMCID: PMC9199550 DOI: 10.2174/1570159x19666210803105232] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 11/22/2022] Open
Abstract
General anesthetics depress excitatory and/or enhance inhibitory synaptic transmission principally by modulating the function of glutamatergic or GABAergic synapses, respectively, with relative anesthetic agent-specific mechanisms. Synaptic signaling proteins, including ligand- and voltage-gated ion channels, are targeted by general anesthetics to modulate various synaptic mechanisms, including presynaptic neurotransmitter release, postsynaptic receptor signaling, and dendritic spine dynamics to produce their characteristic acute neurophysiological effects. As synaptic structure and plasticity mediate higher-order functions such as learning and memory, long-term synaptic dysfunction following anesthesia may lead to undesirable neurocognitive consequences depending on the specific anesthetic agent and the vulnerability of the population. Here we review the cellular and molecular mechanisms of transient and persistent general anesthetic alterations of synaptic transmission and plasticity.
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Affiliation(s)
- Jimcy Platholi
- Cornell University Joan and Sanford I Weill Medical College Ringgold standard institution - Anesthesiology New York, New York. United States
| | - Hugh C Hemmings
- Cornell University Joan and Sanford I Weill Medical College Ringgold standard institution - Anesthesiology New York, New York. United States
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44
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Borgarelli C, Klingl YE, Escamilla-Ayala A, Munck S, Van Den Bosch L, De Borggraeve WM, Ismalaj E. Lighting Up the Plasma Membrane: Development and Applications of Fluorescent Ligands for Transmembrane Proteins. Chemistry 2021; 27:8605-8641. [PMID: 33733502 DOI: 10.1002/chem.202100296] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Indexed: 12/16/2022]
Abstract
Despite the fact that transmembrane proteins represent the main therapeutic targets for decades, complete and in-depth knowledge about their biochemical and pharmacological profiling is not fully available. In this regard, target-tailored small-molecule fluorescent ligands are a viable approach to fill in the missing pieces of the puzzle. Such tools, coupled with the ability of high-precision optical techniques to image with an unprecedented resolution at a single-molecule level, helped unraveling many of the conundrums related to plasma proteins' life-cycle and druggability. Herein, we review the recent progress made during the last two decades in fluorescent ligand design and potential applications in fluorescence microscopy of voltage-gated ion channels, ligand-gated ion channels and G-coupled protein receptors.
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Affiliation(s)
- Carlotta Borgarelli
- Department of Chemistry, Molecular Design and Synthesis, KU Leuven Campus Arenberg Celestijnenlaan 200F -, box 2404, 3001, Leuven, Belgium
| | - Yvonne E Klingl
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium.,Laboratory of Neurobiology, VIB, Center for Brain &, Disease Research, VIB-KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium
| | - Abril Escamilla-Ayala
- Center for Brain & Disease Research, & VIB BioImaging Core, VIB-KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium.,Department of Neurosciences, Leuven Brain Institute, KU Leuven, Campus Gasthuisberg O&N5 - box 602 Herestraat 49, 3000, Leuven, Belgium
| | - Sebastian Munck
- Center for Brain & Disease Research, & VIB BioImaging Core, VIB-KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium.,Department of Neurosciences, Leuven Brain Institute, KU Leuven, Campus Gasthuisberg O&N5 - box 602 Herestraat 49, 3000, Leuven, Belgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium.,Laboratory of Neurobiology, VIB, Center for Brain &, Disease Research, VIB-KU Leuven Campus Gasthuisberg O&N5 -, box 602 Herestraat 49, 3000, Leuven, Belgium
| | - Wim M De Borggraeve
- Department of Chemistry, Molecular Design and Synthesis, KU Leuven Campus Arenberg Celestijnenlaan 200F -, box 2404, 3001, Leuven, Belgium
| | - Ermal Ismalaj
- Department of Chemistry, Molecular Design and Synthesis, KU Leuven Campus Arenberg Celestijnenlaan 200F -, box 2404, 3001, Leuven, Belgium
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45
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Modeling of sustained spontaneous network oscillations of a sexually dimorphic brainstem nucleus: the role of potassium equilibrium potential. J Comput Neurosci 2021; 49:419-439. [PMID: 34032982 DOI: 10.1007/s10827-021-00789-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/15/2021] [Accepted: 04/29/2021] [Indexed: 10/21/2022]
Abstract
Intrinsic oscillators in the central nervous system play a preeminent role in the neural control of rhythmic behaviors, yet little is known about how the ionic milieu regulates their output patterns. A powerful system to address this question is the pacemaker nucleus of the weakly electric fish Apteronotus leptorhynchus. A neural network comprised of an average of 87 pacemaker cells and 20 relay cells produces tonic oscillations, with higher frequencies in males compared to females. Previous empirical studies have suggested that this sexual dimorphism develops and is maintained through modulation of buffering of extracellular K+ by a massive meshwork of astrocytes enveloping the pacemaker and relay cells. Here, we constructed a model of this neural network that can generate sustained spontaneous oscillations. Sensitivity analysis revealed the potassium equilibrium potential, EK (as a proxy of extracellular K+ concentration), and corresponding somatic channel conductances as critical determinants of oscillation frequency and amplitude. In models of both the pacemaker nucleus network and isolated pacemaker and relay cells, the frequency increased almost linearly with EK, whereas the amplitude decreased nonlinearly with increasing EK. Our simulations predict that this frequency increase is largely caused by a shift in the minimum K+ conductance over one oscillation period. This minimum is close to zero at more negative EK, converging to the corresponding maximum at less negative EK. This brings the resting membrane potential closer to the threshold potential at which voltage-gated Na+ channels become active, increasing the excitability, and thus the frequency, of pacemaker and relay cells.
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46
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Zhang L, Peng Z, Bian W, Zhu P, Tang B, Liao WP, Su T. Functional Differences Between Two Kv1.1 RNA Editing Isoforms: a Comparative Study on Neuronal Overexpression in Mouse Prefrontal Cortex. Mol Neurobiol 2021; 58:2046-2060. [PMID: 33411244 DOI: 10.1007/s12035-020-02229-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 11/24/2020] [Indexed: 10/22/2022]
Abstract
The Shaker-related potassium channel Kv1.1 subunit has important implications for controlling neuronal excitabilities. A particular recoding by A-to-I RNA editing at I400 of Kv1.1 mRNA is an underestimated mechanism for fine-tuning the properties of Kv1.1-containing channels. Knowledge about functional differences between edited (I400V) and non-edited Kv1.1 isoforms is insufficient, especially in neurons. To understand their different roles, the two Kv1.1 isoforms were overexpressed in the prefrontal cortex via local adeno-associated virus-mediated gene delivery. The I400V isoform showed a higher competitiveness in membrane translocalization, but failed to reduce current-evoked discharges and showed weaker impact on spiking-frequency adaptation in the transduced neurons. The non-edited Kv1.1 overexpression led to slight elevations in both fast- and non-inactivating current components of macroscopic potassium current. By contrast, the I400V overexpression did not impact the fast-inactivating current component. Further isolation of Kv1.1-specific current by its specific blocker dendrotoxin-κ showed that both isoforms did result in significant increases in current amplitude, whereas the I400V was less efficient in contributing the fast-inactivating current component. Voltage-dependent properties of the fast-inactivating current component did not alter for both isoforms. For recovery kinetics, the I400V showed a significant acceleration of recovery from fast inactivation. The gene delivery of the I400V rather than the wild type exhibited anxiolytic activities, which was assessed by an open field test. These results suggest that the Kv1.1 RNA editing isoforms have different properties and outcomes, reflecting the functional and phenotypic significance of the Kv1.1 RNA editing in neurons.
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Affiliation(s)
- Liting Zhang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Chang-gang-dong Road 250, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Zetong Peng
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Chang-gang-dong Road 250, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Wenjun Bian
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Chang-gang-dong Road 250, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Pingping Zhu
- Department of Neurology, Guangzhou Red Cross Hospital, Medical College, Jinan University, Guangzhou, China
| | - Bin Tang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Chang-gang-dong Road 250, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Wei-Ping Liao
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Chang-gang-dong Road 250, Guangzhou, 510260, China.,Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China
| | - Tao Su
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Chang-gang-dong Road 250, Guangzhou, 510260, China. .,Key Laboratory of Neurogenetics and Channelopathies of the Ministry of Education of China, Guangzhou, China.
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47
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Minakaki G, Krainc D, Burbulla LF. The Convergence of Alpha-Synuclein, Mitochondrial, and Lysosomal Pathways in Vulnerability of Midbrain Dopaminergic Neurons in Parkinson's Disease. Front Cell Dev Biol 2020; 8:580634. [PMID: 33381501 PMCID: PMC7767856 DOI: 10.3389/fcell.2020.580634] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/10/2020] [Indexed: 12/15/2022] Open
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease, characterized by progressive bradykinesia, rigidity, resting tremor, and gait impairment, as well as a spectrum of non-motor symptoms including autonomic and cognitive dysfunction. The cardinal motor symptoms of PD stem from the loss of substantia nigra (SN) dopaminergic (DAergic) neurons, and it remains unclear why SN DAergic neurons are preferentially lost in PD. However, recent identification of several genetic PD forms suggests that mitochondrial and lysosomal dysfunctions play important roles in the degeneration of midbrain dopamine (DA) neurons. In this review, we discuss the interplay of cell-autonomous mechanisms linked to DAergic neuron vulnerability and alpha-synuclein homeostasis. Emerging studies highlight a deleterious feedback cycle, with oxidative stress, altered DA metabolism, dysfunctional lysosomes, and pathological alpha-synuclein species representing key events in the pathogenesis of PD. We also discuss the interactions of alpha-synuclein with toxic DA metabolites, as well as the biochemical links between intracellular iron, calcium, and alpha-synuclein accumulation. We suggest that targeting multiple pathways, rather than individual processes, will be important for developing disease-modifying therapies. In this context, we focus on current translational efforts specifically targeting lysosomal function, as well as oxidative stress via calcium and iron modulation. These efforts could have therapeutic benefits for the broader population of sporadic PD and related synucleinopathies.
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Affiliation(s)
- Georgia Minakaki
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Dimitri Krainc
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Lena F Burbulla
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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48
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Yang JQ, Wang R, Ren Y, Mao JY, Wang ZP, Zhou Y, Han ST. Neuromorphic Engineering: From Biological to Spike-Based Hardware Nervous Systems. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2003610. [PMID: 33165986 DOI: 10.1002/adma.202003610] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/27/2020] [Indexed: 06/11/2023]
Abstract
The human brain is a sophisticated, high-performance biocomputer that processes multiple complex tasks in parallel with high efficiency and remarkably low power consumption. Scientists have long been pursuing an artificial intelligence (AI) that can rival the human brain. Spiking neural networks based on neuromorphic computing platforms simulate the architecture and information processing of the intelligent brain, providing new insights for building AIs. The rapid development of materials engineering, device physics, chip integration, and neuroscience has led to exciting progress in neuromorphic computing with the goal of overcoming the von Neumann bottleneck. Herein, fundamental knowledge related to the structures and working principles of neurons and synapses of the biological nervous system is reviewed. An overview is then provided on the development of neuromorphic hardware systems, from artificial synapses and neurons to spike-based neuromorphic computing platforms. It is hoped that this review will shed new light on the evolution of brain-like computing.
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Affiliation(s)
- Jia-Qin Yang
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Ruopeng Wang
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Yi Ren
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Jing-Yu Mao
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Zhan-Peng Wang
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Ye Zhou
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Su-Ting Han
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, P. R. China
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49
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Pantazis A, Kaneko M, Angelini M, Steccanella F, Westerlund AM, Lindström SH, Nilsson M, Delemotte L, Saitta SC, Olcese R. Tracking the motion of the K V1.2 voltage sensor reveals the molecular perturbations caused by a de novo mutation in a case of epilepsy. J Physiol 2020; 598:5245-5269. [PMID: 32833227 PMCID: PMC8923147 DOI: 10.1113/jp280438] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/14/2020] [Indexed: 12/28/2022] Open
Abstract
KEY POINTS KV1.2 channels, encoded by the KCNA2 gene, regulate neuronal excitability by conducting K+ upon depolarization. A new KCNA2 missense variant was discovered in a patient with epilepsy, causing amino acid substitution F302L at helix S4, in the KV1.2 voltage-sensing domain. Immunocytochemistry and flow cytometry showed that F302L does not impair KCNA2 subunit surface trafficking. Molecular dynamics simulations indicated that F302L alters the exposure of S4 residues to membrane lipids. Voltage clamp fluorometry revealed that the voltage-sensing domain of KV1.2-F302L channels is more sensitive to depolarization. Accordingly, KV1.2-F302L channels opened faster and at more negative potentials; however, they also exhibited enhanced inactivation: that is, F302L causes both gain- and loss-of-function effects. Coexpression of KCNA2-WT and -F302L did not fully rescue these effects. The proband's symptoms are more characteristic of patients with loss of KCNA2 function. Enhanced KV1.2 inactivation could lead to increased synaptic release in excitatory neurons, steering neuronal circuits towards epilepsy. ABSTRACT An exome-based diagnostic panel in an infant with epilepsy revealed a previously unreported de novo missense variant in KCNA2, which encodes voltage-gated K+ channel KV1.2. This variant causes substitution F302L, in helix S4 of the KV1.2 voltage-sensing domain (VSD). F302L does not affect KCNA2 subunit membrane trafficking. However, it does alter channel functional properties, accelerating channel opening at more hyperpolarized membrane potentials, indicating gain of function. F302L also caused loss of KV1.2 function via accelerated inactivation onset, decelerated recovery and shifted inactivation voltage dependence to more negative potentials. These effects, which are not fully rescued by coexpression of wild-type and mutant KCNA2 subunits, probably result from the enhancement of VSD function, as demonstrated by optically tracking VSD depolarization-evoked conformational rearrangements. In turn, molecular dynamics simulations suggest altered VSD exposure to membrane lipids. Compared to other encephalopathy patients with KCNA2 mutations, the proband exhibits mild neurological impairment, more characteristic of patients with KCNA2 loss of function. Based on this information, we propose a mechanism of epileptogenesis based on enhanced KV1.2 inactivation leading to increased synaptic release preferentially in excitatory neurons, and hence the perturbation of the excitatory/inhibitory balance of neuronal circuits.
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Affiliation(s)
- Antonios Pantazis
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
- Division of Neurobiology, Department of Biomedical and Clinical Sciences (BKV), Linköping University, Linköping, Sweden
- Wallenberg Center for Molecular Medicine, Linköping University, Linköping, Sweden
| | - Maki Kaneko
- Center for Personalized Medicine, Children's Hospital, Los Angeles, Los Angeles, CA, USA
- Division of Genomic Medicine, Department of Pathology, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Marina Angelini
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
| | - Federica Steccanella
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
| | - Annie M Westerlund
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden
| | - Sarah H Lindström
- Division of Neurobiology, Department of Biomedical and Clinical Sciences (BKV), Linköping University, Linköping, Sweden
| | - Michelle Nilsson
- Division of Neurobiology, Department of Biomedical and Clinical Sciences (BKV), Linköping University, Linköping, Sweden
| | - Lucie Delemotte
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden
| | - Sulagna C Saitta
- Department of Obstetrics and Gynecology and Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
| | - Riccardo Olcese
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
- Department of Physiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
- Brain Research Institute, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
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50
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Lin P, Lee J, Chen Y, Li F, Ling D. Nanotechnology enabled metal-ion-based disease diagnostics. Sci Bull (Beijing) 2020; 65:1587-1589. [PMID: 36659029 DOI: 10.1016/j.scib.2020.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Peihua Lin
- Institute of Pharmaceutics and Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310058, China
| | - Jiyoung Lee
- Institute of Pharmaceutics and Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Ying Chen
- Institute of Pharmaceutics and Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Fangyuan Li
- Institute of Pharmaceutics and Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310058, China.
| | - Daishun Ling
- Institute of Pharmaceutics and Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou 310058, China.
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