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Pan Y, Kagawa Y, Sun J, Lucas DSD, Takechi R, Mamo JCL, Wai DCC, Norton RS, Jin L, Nicolazzo JA. Peripheral Administration of the Kv1.3-Blocking Peptide HsTX1[R14A] Improves Cognitive Performance in Senescence Accelerated SAMP8 Mice. Neurotherapeutics 2023; 20:1198-1214. [PMID: 37226029 PMCID: PMC10457257 DOI: 10.1007/s13311-023-01387-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/24/2023] [Indexed: 05/26/2023] Open
Abstract
Increased expression of the voltage-gated potassium channel Kv1.3 in activated microglia, and the subsequent release of pro-inflammatory mediators, are closely associated with the progression of Alzheimer's disease (AD). Studies have shown that reducing neuroinflammation through the non-selective blockade of microglial Kv1.3 has the potential to improve cognitive function in mouse models of familial AD. We have previously demonstrated that a potent and highly-selective peptide blocker of Kv1.3, HsTX1[R14A], not only entered the brain parenchyma after peripheral administration in a lipopolysaccharide (LPS)-induced mouse model of inflammation, but also significantly reduced pro-inflammatory mediator release from activated microglia. In this study, we show that microglial expression of Kv1.3 is increased in senescence accelerated mice (SAMP8), an animal model of sporadic AD, and that subcutaneous dosing of HsTX1[R14A] (1 mg/kg) every other day for 8 weeks provided a robust improvement in cognitive deficits in SAMP8 mice. The effect of HsTX1[R14A] on the whole brain was assessed using transcriptomics, which revealed that the expression of genes associated with inflammation, neuron differentiation, synapse function, learning and memory were altered by HsTX1[R14A] treatment. Further study is required to investigate whether these changes are downstream effects of microglial Kv1.3 blockade or a result of alternative mechanisms, including any potential effect of Kv1.3 blockade on other brain cell types. Nonetheless, these results collectively demonstrate the cognitive benefits of Kv1.3 blockade with HsTX1[R14A] in a mouse model of sporadic AD, demonstrating its potential as a therapeutic candidate for this neurodegenerative disease.
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Affiliation(s)
- Yijun Pan
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 3052, Australia
- Department of Organ Anatomy, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Yoshiteru Kagawa
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
- Department of Organ Anatomy, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Jiaqi Sun
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 3052, Australia
| | - Deanna S Deveson Lucas
- Monash Bioinformatics Platform, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Ryusuke Takechi
- School of Biomedical Sciences, Curtin University, Bentley, WA, 6102, Australia
- School of Public Health, Curtin University, Bentley, WA, 6102, Australia
| | - John C L Mamo
- School of Biomedical Sciences, Curtin University, Bentley, WA, 6102, Australia
- School of Public Health, Curtin University, Bentley, WA, 6102, Australia
| | - Dorothy C C Wai
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
- ARC Centre for Fragment-Based Design, Monash University, Parkville, VIC, 3052, Australia
| | - Liang Jin
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, 3052, Australia.
| | - Joseph A Nicolazzo
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia.
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2
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Navarro-Pérez M, Estadella I, Benavente-Garcia A, Orellana-Fernández R, Petit A, Ferreres JC, Felipe A. The Phosphorylation of Kv1.3: A Modulatory Mechanism for a Multifunctional Ion Channel. Cancers (Basel) 2023; 15:2716. [PMID: 37345053 DOI: 10.3390/cancers15102716] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/04/2023] [Accepted: 05/09/2023] [Indexed: 06/23/2023] Open
Abstract
The voltage-gated potassium channel Kv1.3 plays a pivotal role in a myriad of biological processes, including cell proliferation, differentiation, and apoptosis. Kv1.3 undergoes fine-tuned regulation, and its altered expression or function correlates with tumorigenesis and cancer progression. Moreover, posttranslational modifications (PTMs), such as phosphorylation, have evolved as rapid switch-like moieties that tightly modulate channel activity. In addition, kinases are promising targets in anticancer therapies. The diverse serine/threonine and tyrosine kinases function on Kv1.3 and the effects of its phosphorylation vary depending on multiple factors. For instance, Kv1.3 regulatory subunits (KCNE4 and Kvβ) can be phosphorylated, increasing the complexity of channel modulation. Scaffold proteins allow the Kv1.3 channelosome and kinase to form protein complexes, thereby favoring the attachment of phosphate groups. This review compiles the network triggers and signaling pathways that culminate in Kv1.3 phosphorylation. Alterations to Kv1.3 expression and its phosphorylation are detailed, emphasizing the importance of this channel as an anticancer target. Overall, further research on Kv1.3 kinase-dependent effects should be addressed to develop effective antineoplastic drugs while minimizing side effects. This promising field encourages basic cancer research while inspiring new therapy development.
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Affiliation(s)
- María Navarro-Pérez
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
| | - Irene Estadella
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
| | - Anna Benavente-Garcia
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
| | | | - Anna Petit
- Departament de Patologia, Hospital Universitari de Bellvitge, IDIBELL, L'Hospitalet del Llobregat, 08908 Barcelona, Spain
| | - Joan Carles Ferreres
- Servei d'Anatomia Patològica, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA), 08208 Sabadell, Spain
- Departament de Ciències Morfològiques, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
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3
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Revuelta M, Urrutia J, Villarroel A, Casis O. Microglia-Mediated Inflammation and Neural Stem Cell Differentiation in Alzheimer's Disease: Possible Therapeutic Role of K V1.3 Channel Blockade. Front Cell Neurosci 2022; 16:868842. [PMID: 35530176 PMCID: PMC9070300 DOI: 10.3389/fncel.2022.868842] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/31/2022] [Indexed: 12/14/2022] Open
Abstract
Increase of deposits of amyloid β peptides in the extracellular matrix is landmark during Alzheimer’s Disease (AD) due to the imbalance in the production vs. clearance. This accumulation of amyloid β deposits triggers microglial activation. Microglia plays a dual role in AD, a protective role by clearing the deposits of amyloid β peptides increasing the phagocytic response (CD163, IGF-1 or BDNF) and a cytotoxic role, releasing free radicals (ROS or NO) and proinflammatory cytokines (TNF-α, IL-1β) in response to reactive gliosis activated by the amyloid β aggregates. Microglia activation correlated with an increase KV1.3 channels expression, protein levels and current density. Several studies highlight the importance of KV1.3 in the activation of inflammatory response and inhibition of neural progenitor cell proliferation and neuronal differentiation. However, little is known about the pathways of this activation in neural stem cells differentiation and proliferation and the role in amyloid β accumulation. In recent studies using in vitro cells derived from mice models, it has been demonstrated that KV1.3 blockers inhibit microglia-mediated neurotoxicity in culture reducing the expression and production of the pro-inflammatory cytokines IL-1β and TNF-α through the NF-kB and p38MAPK pathway. Overall, we conclude that KV1.3 blockers change the course of AD development, reducing microglial cytotoxic activation and increasing neural stem cell differentiation. However, further investigations are needed to establish the specific pathway and to validate the use of this blocker as therapeutic treatment in Alzheimer patients.
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Affiliation(s)
- Miren Revuelta
- Department of Physiology, Faculty of Medicine and Nursery, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Janire Urrutia
- Department of Physiology, Faculty of Medicine and Nursery, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Alvaro Villarroel
- Instituto Biofisika, Consejo Superior de Investigaciones Científicas (CSIC)-University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), Leioa, Spain
| | - Oscar Casis
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country (UPV/EHU), Vitoria-Gasteiz, Spain
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4
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Maatoug S, Cheikh A, Khamessi O, Tabka H, Landoulsi Z, Guigonis JM, Diochot S, Bendahhou S, Benkhalifa R. Cross Pharmacological, Biochemical and Computational Studies of a Human Kv3.1b Inhibitor from Androctonus australis Venom. Int J Mol Sci 2021; 22:ijms222212290. [PMID: 34830172 PMCID: PMC8618407 DOI: 10.3390/ijms222212290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/05/2021] [Accepted: 11/11/2021] [Indexed: 11/23/2022] Open
Abstract
The voltage-gated K+ channels Kv3.1 display fast activation and deactivation kinetics and are known to have a crucial contribution to the fast-spiking phenotype of certain neurons. AahG50, as a natural product extracted from Androctonus australis hector venom, inhibits selectively Kv3.1 channels. In the present study, we focused on the biochemical and pharmacological characterization of the component in AahG50 scorpion venom that potently and selectively blocks the Kv3.1 channels. We used a combined optimization through advanced biochemical purification and patch-clamp screening steps to characterize the peptide in AahG50 active on Kv3.1 channels. We described the inhibitory effect of a toxin on Kv3.1 unitary current in black lipid bilayers. In silico, docking experiments are used to study the molecular details of the binding. We identified the first scorpion venom peptide inhibiting Kv3.1 current at 170 nM. This toxin is the alpha-KTx 15.1, which occludes the Kv3.1 channel pore by means of the lysine 27 lateral chain. This study highlights, for the first time, the modulation of the Kv3.1 by alpha-KTx 15.1, which could be an interesting starting compound for developing therapeutic biomolecules against Kv3.1-associated diseases.
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Affiliation(s)
- Sonia Maatoug
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Correspondence: (S.M.); (R.B.); Tel.: +216-98-81-27-32 (R.B.)
| | - Amani Cheikh
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
| | - Oussema Khamessi
- Laboratoire des Biomolécules Thérapeutiques, Institut Pasteur de Tunis, Université de Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia;
| | - Hager Tabka
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Faculté des Sciences de Bizerte, Université de Carthage, Bizerte 7021, Tunisia
| | - Zied Landoulsi
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
| | - Jean-Marie Guigonis
- Laboratory Transporter in Imaging and Radiotherapy in Oncology (TIRO), Direction de la Recherche Fondamentale (DRF), Institut des Sciences du Vivant Fréderic Joliot, Commissariat à l′Energie Atomique et aux Énergies Alternatives (CEA), Université Côte d’Azur, F-06107 Nice, France;
| | - Sylvie Diochot
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France;
| | - Saïd Bendahhou
- UMR7370 CNRS, LP2M, Université Côte d’Azur, Labex ICST, Nice, France;
| | - Rym Benkhalifa
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Correspondence: (S.M.); (R.B.); Tel.: +216-98-81-27-32 (R.B.)
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5
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Tajti G, Wai DCC, Panyi G, Norton RS. The voltage-gated potassium channel K V1.3 as a therapeutic target for venom-derived peptides. Biochem Pharmacol 2020; 181:114146. [PMID: 32653588 DOI: 10.1016/j.bcp.2020.114146] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/05/2020] [Accepted: 07/07/2020] [Indexed: 02/07/2023]
Abstract
The voltage-gated potassium channel KV1.3 is a well-established therapeutic target for a range of autoimmune diseases, in addition to being the site of action of many venom-derived peptides. Numerous studies have documented the efficacy of venom peptides that target KV1.3, in particular from sea anemones and scorpions, in animal models of autoimmune diseases such as rheumatoid arthritis, psoriasis and multiple sclerosis. Moreover, an analogue of the sea anemone peptide ShK (known as dalazatide) has successfully completed Phase 1 clinical trials in mild-to-moderate plaque psoriasis. In this article we consider other potential therapeutic applications of inhibitors of KV1.3, including in inflammatory bowel disease and neuroinflammatory conditions such as Alzheimer's and Parkinson's diseases, as well as fibrotic diseases. We also summarise strategies for facilitating the entry of peptides to the central nervous system, given that this will be a pre-requisite for the treatment of most neuroinflammatory diseases. Venom-derived peptides that have been reported recently to target KV1.3 are also described. The increasing number of autoimmune and other conditions in which KV1.3 is upregulated and is therefore a potential therapeutic target, combined with the fact that many venom-derived peptides are potent inhibitors of KV1.3, suggests that venoms are likely to continue to serve as a rich source of new pharmacological tools and therapeutic leads targeting this channel.
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Affiliation(s)
- Gabor Tajti
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Dorothy C C Wai
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary.
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia; ARC Centre for Fragment-Based Design, Monash University, Parkville, VIC 3052, Australia.
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6
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Levin M, Pietak AM, Bischof J. Planarian regeneration as a model of anatomical homeostasis: Recent progress in biophysical and computational approaches. Semin Cell Dev Biol 2019; 87:125-144. [PMID: 29635019 PMCID: PMC6234102 DOI: 10.1016/j.semcdb.2018.04.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 04/03/2018] [Accepted: 04/06/2018] [Indexed: 12/22/2022]
Abstract
Planarian behavior, physiology, and pattern control offer profound lessons for regenerative medicine, evolutionary biology, morphogenetic engineering, robotics, and unconventional computation. Despite recent advances in the molecular genetics of stem cell differentiation, this model organism's remarkable anatomical homeostasis provokes us with truly fundamental puzzles about the origin of large-scale shape and its relationship to the genome. In this review article, we first highlight several deep mysteries about planarian regeneration in the context of the current paradigm in this field. We then review recent progress in understanding of the physiological control of an endogenous, bioelectric pattern memory that guides regeneration, and how modulating this memory can permanently alter the flatworm's target morphology. Finally, we focus on computational approaches that complement reductive pathway analysis with synthetic, systems-level understanding of morphological decision-making. We analyze existing models of planarian pattern control and highlight recent successes and remaining knowledge gaps in this interdisciplinary frontier field.
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Affiliation(s)
- Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, United States; Biology Department, Tufts University, Medford, MA 02155, United States.
| | - Alexis M Pietak
- Allen Discovery Center at Tufts University, Medford, MA 02155, United States
| | - Johanna Bischof
- Allen Discovery Center at Tufts University, Medford, MA 02155, United States; Biology Department, Tufts University, Medford, MA 02155, United States
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7
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Marichal N, Reali C, Rehermann MI, Trujillo-Cenóz O, Russo RE. Progenitors in the Ependyma of the Spinal Cord: A Potential Resource for Self-Repair After Injury. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1015:241-264. [DOI: 10.1007/978-3-319-62817-2_13] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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8
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Kaczmarek LK, Zhang Y. Kv3 Channels: Enablers of Rapid Firing, Neurotransmitter Release, and Neuronal Endurance. Physiol Rev 2017; 97:1431-1468. [PMID: 28904001 PMCID: PMC6151494 DOI: 10.1152/physrev.00002.2017] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/24/2017] [Accepted: 05/05/2017] [Indexed: 12/11/2022] Open
Abstract
The intrinsic electrical characteristics of different types of neurons are shaped by the K+ channels they express. From among the more than 70 different K+ channel genes expressed in neurons, Kv3 family voltage-dependent K+ channels are uniquely associated with the ability of certain neurons to fire action potentials and to release neurotransmitter at high rates of up to 1,000 Hz. In general, the four Kv3 channels Kv3.1-Kv3.4 share the property of activating and deactivating rapidly at potentials more positive than other channels. Each Kv3 channel gene can generate multiple protein isoforms, which contribute to the high-frequency firing of neurons such as auditory brain stem neurons, fast-spiking GABAergic interneurons, and Purkinje cells of the cerebellum, and to regulation of neurotransmitter release at the terminals of many neurons. The different Kv3 channels have unique expression patterns and biophysical properties and are regulated in different ways by protein kinases. In this review, we cover the function, localization, and modulation of Kv3 channels and describe how levels and properties of the channels are altered by changes in ongoing neuronal activity. We also cover how the protein-protein interaction of these channels with other proteins affects neuronal functions, and how mutations or abnormal regulation of Kv3 channels are associated with neurological disorders such as ataxias, epilepsies, schizophrenia, and Alzheimer's disease.
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Affiliation(s)
- Leonard K Kaczmarek
- Departments of Pharmacology and of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Yalan Zhang
- Departments of Pharmacology and of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
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9
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Minovi A, Aguado A, Brunert D, Kurtenbach S, Dazert S, Hatt H, Conrad H. Isolation, culture optimization and functional characterization of stem cell neurospheres from mouse neonatal olfactory bulb and epithelium. Eur Arch Otorhinolaryngol 2017; 274:3071-3085. [PMID: 28478501 DOI: 10.1007/s00405-017-4590-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/25/2017] [Indexed: 10/19/2022]
Abstract
The olfactory epithelium contains basal cells with stem cell characteristics, which have the capacity to differentiate throughout life into olfactory receptor neurons (ORNs). Here we investigate the in vitro characteristics of stem cells taken from the olfactory bulb (OB) and the olfactory epithelium (OE) of neonatal TIS21 knock-in mice. The major aim of the study was the generation of olfactory neurospheres (ONS) derived from OB and OE of neonatal mice as a tool to further analyze the elementary processes of ORN development. Our data showed that the presence of epidermal growth factor (EGF) and fibroblast growth factor (FGF) leads to a significant increase in number of ONS derived from OB but not from OE. The differentiation of ONSs led to the formation of different neuronal cell types, in particular to bipolar-shaped cells as well as putative pyramidal-neurons, astrocytes and oligodendrocytes. Immunohistochemical staining confirmed the presence of astrocytes and neurons in both types of ONSs. In order to investigate the functionality of the neurons we performed calcium imaging and patch-clamp experiments. Calcium imaging experiments revealed that the application of high potassium concentration provokes calcium transients. No excitable properties, neither sodium currents nor action potentials, were observed for the bipolar-shaped cells derived from OB and OE neurospheres, which means that these types of cells morphologically defined as putative neuronal cells, were not physiologically active. Interestingly, patch-clamp recordings performed in the pyramidal-shaped cells of OB neurospheres showed sodium and potassium currents as well as action potentials. Our study will help to establish further models in the field of olfactology.
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Affiliation(s)
- Amir Minovi
- Department of Otorhinolaryngology, Head and Neck Surgery, St. Elisabeth Hospital, Ruhr-University Bochum, Bleichstr. 15, 44787, Bochum, Germany.
| | - Ainhara Aguado
- Department of Otorhinolaryngology, Head and Neck Surgery, St. Elisabeth Hospital, Ruhr-University Bochum, Bleichstr. 15, 44787, Bochum, Germany.,Department of Cell Physiology, Ruhr-University Bochum, Universitätstrasse 150, 44801, Bochum, Germany
| | - Daniela Brunert
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074, Aachen, Germany
| | - Stefan Kurtenbach
- Department of Cell Physiology, Ruhr-University Bochum, Universitätstrasse 150, 44801, Bochum, Germany
| | - Stefan Dazert
- Department of Otorhinolaryngology, Head and Neck Surgery, St. Elisabeth Hospital, Ruhr-University Bochum, Bleichstr. 15, 44787, Bochum, Germany
| | - Hanns Hatt
- Department of Cell Physiology, Ruhr-University Bochum, Universitätstrasse 150, 44801, Bochum, Germany
| | - Heike Conrad
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
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10
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Poirier K, Viot G, Lombardi L, Jauny C, Billuart P, Bienvenu T. Loss of Function of KCNC1 is associated with intellectual disability without seizures. Eur J Hum Genet 2017; 25:560-564. [PMID: 28145425 DOI: 10.1038/ejhg.2017.3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 12/09/2016] [Accepted: 12/24/2016] [Indexed: 11/10/2022] Open
Abstract
p.(Arg320His) mutation in the KCNC1 gene in human 11p15.1 has recently been identified in patients with progressive myoclonus epilepsies, a group of rare inherited disorders manifesting with action myoclonus, myoclonic epilepsy, and ataxia. This KCNC1 variant causes a dominant-negative effect. Here we describe three patients from the same family with intellectual disability and dysmorphic features. The three affected individuals carry a c.1015C>T (p.(Arg339*)) nonsense variant in KCNC1 gene. As previously observed in the mutant mouse carrying a disrupted KCNC1 gene, these findings reveal that individuals with a KCNC1 loss-of-function variant can present intellectual disability without seizure and epilepsy.
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Affiliation(s)
- Karine Poirier
- Inserm, U1016, Institut Cochin, Paris, France.,Cnrs, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Géraldine Viot
- Unité de Génétique Clinique, Maternité Port-Royal, HUPC, Hôpital Cochin, Paris, France
| | - Laura Lombardi
- Inserm, U1016, Institut Cochin, Paris, France.,Cnrs, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Clémence Jauny
- Unité de Génétique Clinique, Maternité Port-Royal, HUPC, Hôpital Cochin, Paris, France
| | - Pierre Billuart
- Inserm, U1016, Institut Cochin, Paris, France.,Cnrs, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Thierry Bienvenu
- Inserm, U1016, Institut Cochin, Paris, France.,Cnrs, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Assistance Publique-Hôpitaux de Paris, Groupe Universitaire Paris Centre, Site Cochin, Laboratoire de Biochimie et Génétique Moléculaire, Paris, France
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11
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Shen H, Bocksteins E, Kondrychyn I, Snyders D, Korzh V. Functional antagonism of voltage-gated K+ channel α-subunits in the developing brain ventricular system. Development 2016; 143:4249-4260. [PMID: 27729411 DOI: 10.1242/dev.140467] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/30/2016] [Indexed: 01/10/2023]
Abstract
The brain ventricular system is essential for neurogenesis and brain homeostasis. Its neuroepithelial lining effects these functions, but the underlying molecular pathways remain to be understood. We found that the potassium channels expressed in neuroepithelial cells determine the formation of the ventricular system. The phenotype of a novel zebrafish mutant characterized by denudation of neuroepithelial lining of the ventricular system and hydrocephalus is mechanistically linked to Kcng4b, a homologue of the 'silent' voltage-gated potassium channel α-subunit Kv6.4. We demonstrated that Kcng4b modulates proliferation of cells lining the ventricular system and maintains their integrity. The gain of Kcng4b function reduces the size of brain ventricles. Electrophysiological studies suggest that Kcng4b mediates its effects via an antagonistic interaction with Kcnb1, the homologue of the electrically active delayed rectifier potassium channel subunit Kv2.1. Mutation of kcnb1 reduces the size of the ventricular system and its gain of function causes hydrocephalus, which is opposite to the function of Kcng4b. This demonstrates the dynamic interplay between potassium channel subunits in the neuroepithelium as a novel and crucial regulator of ventricular development in the vertebrate brain.
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Affiliation(s)
| | - Elke Bocksteins
- Department for Biomedical Sciences, University of Antwerp, Wilrijk B-2610, Belgium
| | | | - Dirk Snyders
- Department for Biomedical Sciences, University of Antwerp, Wilrijk B-2610, Belgium
| | - Vladimir Korzh
- Institute of Molecular and Cell Biology, Singapore .,Department of Biological Sciences, National University of Singapore, 117543, Singapore
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12
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Martínez-Mármol R, Comes N, Styrczewska K, Pérez-Verdaguer M, Vicente R, Pujadas L, Soriano E, Sorkin A, Felipe A. Unconventional EGF-induced ERK1/2-mediated Kv1.3 endocytosis. Cell Mol Life Sci 2015; 73:1515-28. [PMID: 26542799 DOI: 10.1007/s00018-015-2082-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 10/14/2015] [Accepted: 10/26/2015] [Indexed: 12/13/2022]
Abstract
The potassium channel Kv1.3 plays roles in immunity, neuronal development and sensory discrimination. Regulation of Kv1.3 by kinase signaling has been studied. In this context, EGF binds to specific receptors (EGFR) and triggers tyrosine kinase-dependent signaling, which down-regulates Kv1.3 currents. We show that Kv1.3 undergoes EGF-dependent endocytosis. This EGF-mediated mechanism is relevant because is involved in adult neural stem cell fate determination. We demonstrated that changes in Kv1.3 subcellular distribution upon EGFR activation were due to Kv1.3 clathrin-dependent endocytosis, which targets the Kv1.3 channels to the lysosomal degradative pathway. Interestingly, our results further revealed that relevant tyrosines and other interacting motifs, such as PDZ and SH3 domains, were not involved in the EGF-dependent Kv1.3 internalization. However, a new, and yet undescribed mechanism, of ERK1/2-mediated threonine phosphorylation is crucial for the EGF-mediated Kv1.3 endocytosis. Our results demonstrate that EGF triggers the down-regulation of Kv1.3 activity and its expression at the cell surface, which is important for the development and migration of adult neural progenitors.
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Affiliation(s)
- Ramón Martínez-Mármol
- Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Barcelona, Spain.,Departament de Biologia Celular, Universitat de Barcelona, Barcelona, Spain
| | - Núria Comes
- Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Barcelona, Spain
| | - Katarzyna Styrczewska
- Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Barcelona, Spain
| | - Mireia Pérez-Verdaguer
- Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Barcelona, Spain
| | - Rubén Vicente
- Laboratory of Molecular Physiology and Channelopathies, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
| | - Lluís Pujadas
- Departament de Biologia Celular, Universitat de Barcelona, Barcelona, Spain
| | - Eduardo Soriano
- Departament de Biologia Celular, Universitat de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain.,Vall d´Hebron Institute of Research (VHIR) and Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Alexander Sorkin
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina (IBUB), Barcelona, Spain. .,Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain.
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13
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Wang D, Liu Y, Lu P, Zhu D, Zhu Y. 15-oxo-ETE-induced internal carotid artery constriction in hypoxic rats is mediated by potassium channels. Physiol Res 2015; 65:391-9. [PMID: 26447508 DOI: 10.33549/physiolres.933001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Our own study as well as others have previously reported that hypoxia activates 15-lipoxygenase (15-LO) in the brain, causing a series of chain reactions, which exacerbates ischemic stroke. 15-hydroxyeicosatetraenoic acid (15-HETE) and 15-oxo-eicosatetraenoic acid (15-oxo-ETE/15-KETE) are 15-LO-specific metabolites of arachidonic acid (AA). 15-HETE was found to be rapidly converted into 15-oxo-ETE by 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in some circumstances. We have demonstrated that 15-HETE promotes cerebral vasoconstriction during hypoxia. However, the effect of 15-oxo-ETE upon the contraction of cerebral vasculature remains unclear. To investigate this effect and to clarify the underlying mechanism, we performed immunohistochemistry and Western blot to test the expression of 15-PGDH in rat cerebral tissue, examined internal carotid artery (ICA) tension in isolated rat ICA rings. Western blot and reverse transcription polymerase chain reaction (RT-PCR) were used to analyze the expression of voltage-gated potassium (Kv) channels (Kv2.1, Kv1.5, and Kv1.1) in cultured cerebral arterial smooth muscle cells (CASMCs). The results showed that the levels of 15-PGDH expression were drastically elevated in the cerebral of rats with hypoxia, and 15-oxo-ETE enhanced ICA contraction in a dose-dependent manner. This effect was more significant in the hypoxic rats than in the normoxic rats. We also found that 15-oxo-ETE significantly attenuated the expression of Kv2.1 and Kv1.5, but not Kv1.1. In conclusion, these results suggest that 15-oxo-ETE leads to the contraction of the ICA, especially under hypoxic conditions and that specific Kv channels may play an important role in 15-oxo-ETE-induced ICA constriction.
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Affiliation(s)
- D Wang
- Department of Neurology, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China.
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14
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Levin M. Molecular bioelectricity: how endogenous voltage potentials control cell behavior and instruct pattern regulation in vivo. Mol Biol Cell 2015; 25:3835-50. [PMID: 25425556 PMCID: PMC4244194 DOI: 10.1091/mbc.e13-12-0708] [Citation(s) in RCA: 221] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In addition to biochemical gradients and transcriptional networks, cell behavior is regulated by endogenous bioelectrical cues originating in the activity of ion channels and pumps, operating in a wide variety of cell types. Instructive signals mediated by changes in resting potential control proliferation, differentiation, cell shape, and apoptosis of stem, progenitor, and somatic cells. Of importance, however, cells are regulated not only by their own Vmem but also by the Vmem of their neighbors, forming networks via electrical synapses known as gap junctions. Spatiotemporal changes in Vmem distribution among nonneural somatic tissues regulate pattern formation and serve as signals that trigger limb regeneration, induce eye formation, set polarity of whole-body anatomical axes, and orchestrate craniofacial patterning. New tools for tracking and functionally altering Vmem gradients in vivo have identified novel roles for bioelectrical signaling and revealed the molecular pathways by which Vmem changes are transduced into cascades of downstream gene expression. Because channels and gap junctions are gated posttranslationally, bioelectrical networks have their own characteristic dynamics that do not reduce to molecular profiling of channel expression (although they couple functionally to transcriptional networks). The recent data provide an exciting opportunity to crack the bioelectric code, and learn to program cellular activity at the level of organs, not only cell types. The understanding of how patterning information is encoded in bioelectrical networks, which may require concepts from computational neuroscience, will have transformative implications for embryogenesis, regeneration, cancer, and synthetic bioengineering.
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Affiliation(s)
- Michael Levin
- Biology Department, Center for Regenerative and Developmental Biology, Tufts University, Medford, MA 02155-4243
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15
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Zhou YY, Hou GQ, He SW, Xiao Z, Xu HJ, Qiu YT, Jiang S, Zheng H, Li ZY. Psora-4, a Kv1.3 Blocker, Enhances Differentiation and Maturation in Neural Progenitor Cells. CNS Neurosci Ther 2015; 21:558-67. [PMID: 25976092 DOI: 10.1111/cns.12402] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 04/12/2015] [Accepted: 04/14/2015] [Indexed: 01/01/2023] Open
Abstract
AIM The self-repair ability of neural progenitor cells (NPCs) has been found to be activated and protected in several therapies helpful in multiple sclerosis (MS), an inflammatory demyelinating disease of the CNS. As a potential therapeutic target in MS, the role of the ion channel Kv1.3 in NPC self-repair has received limited attention. The aim of this study was to explore the effects of a selective Kv1.3 blocker on NPC neuronal differentiation and maturation. METHODS A small-molecule selective blocker for Kv1.3, Psora-4, was added to the differentiation medium of cultured mouse NPCs to assess its effect on NPC differentiation efficiency. Both a polypeptide Kv1.3 blocker and Kv1.3-specific RNA interference were used in parallel experiments. Further, the maturity of newborn neurons in the presence of Psora-4 was measured both by morphological analysis and by whole-cell patch clamping. RESULTS Psora-4 induced a significant increase in the percentage of neurons. Knockdown of Kv1.3 in NPCs also promoted neuronal differentiation. Both morphological and electrophysiological analyses suggested that NPC-derived neurons in the presence of Psora-4 were more mature. CONCLUSION Our studies reveal a crucial role for the ion channel Kv1.3 in the regulation of NPC differentiation and maturation, making Psora-4 a promising candidate molecule for MS treatment.
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Affiliation(s)
- Yu-Ye Zhou
- Key Laboratory of Regenerative Biology, South China Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Guo-Qiang Hou
- Key Laboratory of Regenerative Biology, South China Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Song-Wei He
- Key Laboratory of Regenerative Biology, South China Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Zhuo Xiao
- Key Laboratory of Regenerative Biology, South China Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Hui-Juan Xu
- Key Laboratory of Regenerative Biology, South China Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Ya-Tao Qiu
- Institute of Chemical Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Sheng Jiang
- Institute of Chemical Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Hui Zheng
- Key Laboratory of Regenerative Biology, South China Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Zhi-Yuan Li
- Key Laboratory of Regenerative Biology, South China Institute of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong, China.,Department of Anatomy and Neurobiology, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
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16
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Scorpion venom heat-resistant peptide (SVHRP) enhances neurogenesis and neurite outgrowth of immature neurons in adult mice by up-regulating brain-derived neurotrophic factor (BDNF). PLoS One 2014; 9:e109977. [PMID: 25299676 PMCID: PMC4192587 DOI: 10.1371/journal.pone.0109977] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 09/10/2014] [Indexed: 12/20/2022] Open
Abstract
Scorpion venom heat-resistant peptide (SVHRP) is a component purified from Buthus martensii Karsch scorpion venom. Although scorpions and their venom have been used in Traditional Chinese Medicine (TCM) to treat chronic neurological disorders, the underlying mechanisms of these treatments remain unknown. We applied SVHRP in vitro and in vivo to understand its effects on the neurogenesis and maturation of adult immature neurons and explore associated molecular mechanisms. SVHRP administration increased the number of 5-bromo-2’-dexoxyuridine (BrdU)-positive cells, BrdU- positive/neuron-specific nuclear protein (NeuN)-positive neurons, and polysialylated-neural cell adhesion molecule (PSA-NCAM)-positive immature neurons in the subventricular zone (SVZ) and subgranular zone (SGZ) of hippocampus. Furthermore immature neurons incubated with SVHRP-pretreated astrocyte-conditioned medium exhibited significantly increased neurite length compared with those incubated with normal astrocyte-conditioned medium. This neurotrophic effect was further confirmed in vivo by detecting an increased average single area and whole area of immature neurons in the SGZ, SVZ and olfactory bulb (OB) in the adult mouse brain. In contrast to normal astrocyte-conditioned medium, higher concentrations of brain-derived neurotrophic factor (BDNF) but not nerve growth factor (NGF) or glial cell line-derived neurotrophic factor (GDNF) was detected in the conditioned medium of SVHRP-pretreated astrocytes, and blocking BDNF using anti-BDNF antibodies eliminated these SVHRP-dependent neurotrophic effects. In SVHRP treated mouse brain, more glial fibrillary acidic protein (GFAP)-positive cells were detected. Furthermore, immunohistochemistry revealed increased numbers of GFAP/BDNF double-positive cells, which agrees with the observed changes in the culture system. This paper describes novel effects of scorpion venom-originated peptide on the stem cells and suggests the potential therapeutic values of SVHRP.
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17
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Thell K, Hellinger R, Schabbauer G, Gruber CW. Immunosuppressive peptides and their therapeutic applications. Drug Discov Today 2013; 19:645-53. [PMID: 24333193 PMCID: PMC4042018 DOI: 10.1016/j.drudis.2013.12.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/12/2013] [Accepted: 12/04/2013] [Indexed: 12/21/2022]
Abstract
T cell signaling has a pivotal role in autoimmunity and immunosuppression. Immunosuppressive pharmaceuticals often exhibit severe side-effects in patients. Gene-encoded peptides have potential as immunosuppressive drug candidates. Cyclotides are stable peptides that offer enhanced oral administration properties.
The immune system is vital for detecting and evading endogenous and exogenous threats to the body. Failure to regulate this homeostasis leads to autoimmunity, which is often associated with malfunctioning T cell signaling. Several medications are available to suppress over-reactive T lymphocytes, but many of the currently marketed drugs produce severe and life-threatening side-effects. Ribosomally synthesized peptides are gaining recognition from the pharmaceutical industry for their enhanced selectivity and decreased toxicity compared with small molecules; in particular, circular peptides exhibit remarkable stability and increased oral administration properties. For example, plant cyclotides effectively inhibit T lymphocyte proliferation. They are composed of a head-to-tail cyclized backbone and a cystine-knot motif, which confers them with remarkable stability, thus making them attractive pharmaceutical tools.
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Affiliation(s)
- Kathrin Thell
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstr. 17, A-1090 Vienna, Austria
| | - Roland Hellinger
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstr. 17, A-1090 Vienna, Austria
| | - Gernot Schabbauer
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstr. 17, A-1090 Vienna, Austria
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstr. 17, A-1090 Vienna, Austria.
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18
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Peng Y, Lu K, Li Z, Zhao Y, Wang Y, Hu B, Xu P, Shi X, Zhou B, Pennington M, Chandy KG, Tang Y. Blockade of Kv1.3 channels ameliorates radiation-induced brain injury. Neuro Oncol 2013; 16:528-39. [PMID: 24305723 DOI: 10.1093/neuonc/not221] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Tumors affecting the head, neck, and brain account for significant morbidity and mortality. The curative efficacy of radiotherapy for these tumors is well established, but radiation carries a significant risk of neurologic injury. So far, neuroprotective therapies for radiation-induced brain injury are still limited. In this study we demonstrate that Stichodactyla helianthus (ShK)-170, a specific inhibitor of the voltage-gated potassium (Kv)1.3 channel, protected mice from radiation-induced brain injury. METHODS Mice were treated with ShK-170 for 3 days immediately after brain irradiation. Radiation-induced brain injury was assessed by MRI scans and a Morris water maze. Pathophysiological change of the brain was measured by immunofluorescence. Gene and protein expressions of Kv1.3 and inflammatory factors were measured by quantitative real-time PCR, reverse transcription PCR, ELISA assay, and western blot analyses. Kv currents were recorded in the whole-cell configuration of the patch-clamp technique. RESULTS Radiation increased Kv1.3 mRNA and protein expression in microglia. Genetic silencing of Kv1.3 by specific short interference RNAs or pharmacological blockade with ShK-170 suppressed radiation-induced production of the proinflammatory factors interleukin-6, cyclooxygenase-2, and tumor necrosis factor-α by microglia. ShK-170 also inhibited neurotoxicity mediated by radiation-activated microglia and promoted neurogenesis by increasing the proliferation of neural progenitor cells. CONCLUSIONS The therapeutic effect of ShK-170 is mediated by suppression of microglial activation and microglia-mediated neurotoxicity and enhanced neurorestoration by promoting proliferation of neural progenitor cells.
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Affiliation(s)
- Ying Peng
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China (Y.P., K.L., Z.L., Y.W., B.H., P.X., X.S., Y.T.); Department of Neurosurgery, Shanghai 10th People's Hospital, Tongji University, Shanghai, China (Y.Z., B.Z.); Peptides International, Louisville, Kentucky (M.P.); Department of Physiology and Biophysics, University of California, Irvine, Irvine, California (K.G.C.)
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19
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Duque A, Gazula VR, Kaczmarek LK. Expression of Kv1.3 potassium channels regulates density of cortical interneurons. Dev Neurobiol 2013; 73:841-55. [PMID: 23821603 DOI: 10.1002/dneu.22105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 06/19/2013] [Accepted: 06/21/2013] [Indexed: 01/27/2023]
Abstract
The Kv1.3 protein is a member of the large family of voltage-dependent K+ subunits (Kv channels), which assemble to form tetrameric membrane-spanning channels that provide a selective pore for the conductance of K+ across the cell membrane. Kv1.3 differs from most other Kv channels in that deletion of Kv1.3 gene produces very striking changes in development and structure of the olfactory bulb, where Kv1.3 is expressed at high levels, resulting in a lower threshold for detection of odors, an increased number of synaptic glomeruli and alterations in the levels of a variety of neuronal signaling molecules. Because Kv1.3 is also expressed in the cerebral cortex, we have now examined the effects of deletion of the Kv1.3 gene on the expression of interneuron populations of the cerebral cortex. Using unbiased stereology we found an increase in the number of parvalbumin (PV) cells in whole cerebral cortex of Kv1.3-/- mice relative to that in wild-type mice, and a decrease in the number of calbindin (CB), calretinin (CR), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and somatostatin (SOM) interneurons. These changes are accompanied by a decrease in the cortical volume such that the cell density of PV interneurons is significantly increased and that of SOM neurons is decreased in Kv1.3-/- animals. Our studies suggest that, as in the olfactory bulb, Kv1.3 plays a unique role in neuronal differentiation and/or survival of interneuron populations and that expression of Kv1.3 is required for normal cortical function.
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Affiliation(s)
- Alvaro Duque
- Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut, 06520
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20
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Kodama D, Togari A. Noradrenaline stimulates cell proliferation by suppressing potassium channels via G(i/o) -protein-coupled α(1B) -adrenoceptors in human osteoblasts. Br J Pharmacol 2013; 168:1230-9. [PMID: 23061915 DOI: 10.1111/bph.12000] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 09/20/2012] [Accepted: 09/24/2012] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Recent studies demonstrated that the sympathetic nervous system regulates bone metabolism via β(2) -adrenoceptors. Although α-adrenoceptors are also expressed in osteogenic cells, their functions in bone metabolism have been less studied. We previously demonstrated that noradrenaline suppressed potassium currents via α(1B) -adrenoceptors in the human osteoblast SaM-1 cell line. The aim of this study was to investigate the signal transduction pathway and the physiological role of noradrenaline in human osteoblasts in more detail. EXPERIMENTAL APPROACH To investigate signal transduction through α(1B) -adrenoceptors, we used whole-cell patch clamp recording and Ca fluorescence imaging. Potassium channels regulate membrane potential and cell proliferation activity in non-excitable cells, so we evaluated cell proliferation activity by BrdU incorporation and WST assay. KEY RESULTS In SaM-1 cells, bath-applied noradrenaline elevated intracellular Ca(2+) concentration and this effect was abolished by both chloroethylclonidine, an α(1B) -adrenoceptor antagonist, and U73122, a PLC inhibitor. However, the inhibitory effect of noradrenaline on whole-cell current was unaffected by U73122. In contrast, in cells pretreated with either Pertussis toxin, a G(i/o) -protein-coupled receptor inhibitor, or gallein, a Gβγ-protein inhibitor, the inhibitory effect of noradrenaline on whole-cell current was significantly suppressed. Noradrenaline-induced enhancement of cell proliferation was inhibited by CsCl, a non-selective potassium channel blocker, gallein and H89, a PKA inhibitor, but not by U73122. CONCLUSIONS AND IMPLICATIONS Noradrenaline facilitated cell proliferation by regulation of potassium currents in human osteoblasts via G(i/o) -protein-coupled α(1B) -adrenoceptors, not via coupling to Gq-proteins.
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Affiliation(s)
- D Kodama
- Department of Pharmacology, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
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21
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Chao J, Yang L, Buch S, Gao L. Angiotensin II increased neuronal stem cell proliferation: role of AT2R. PLoS One 2013; 8:e63488. [PMID: 23691054 PMCID: PMC3655161 DOI: 10.1371/journal.pone.0063488] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 04/03/2013] [Indexed: 01/09/2023] Open
Abstract
Angiotensin II (Ang II), known a potent vasoactive substance in the renin-angiotensin system in the brain, plays a critical role in systemic blood pressure control. However, increasing evidence indicated that the physiological role of Ang II go beyond its vasoactive effect. In the present study, we demonstrated that Ang II type-1 receptor (AT1R) and type-2 receptor (AT2R) were expressed in primary rat hippocampal neuronal stem cells (NSCs). Treatment of rat hippocampal NSCs with Ang II increased cell proliferation. Pretreatment of NSCs with specific AT2R, but not AT1R, antagonist significantly suppressed Ang II-induced cell proliferation. Furthermore, Ang II stimulated ERK and Akt phosphorylation in NSCs. Pretreatment of MEK inhibitor, but not PI3K inhibitor, inhibited Ang II-induced ERK phosphorylation as well as cell proliferation. In addition, stimulation of NSCs with Ang II decreased expression of KV 1.2/KV 3.1 channels and blocked K+ currents which lie downstream of ERK activation. Taken together, these findings underpin the role of AT2R as a novel target that regulates cell proliferation mediated by Ang II with implications for therapeutic intervention for regulation of neurogenesis.
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Affiliation(s)
- Jie Chao
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Lu Yang
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Lie Gao
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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22
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Adams DS, Levin M. Endogenous voltage gradients as mediators of cell-cell communication: strategies for investigating bioelectrical signals during pattern formation. Cell Tissue Res 2013; 352:95-122. [PMID: 22350846 PMCID: PMC3869965 DOI: 10.1007/s00441-012-1329-4] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 01/12/2012] [Indexed: 01/07/2023]
Abstract
Alongside the well-known chemical modes of cell-cell communication, we find an important and powerful system of bioelectrical signaling: changes in the resting voltage potential (Vmem) of the plasma membrane driven by ion channels, pumps and gap junctions. Slow Vmem changes in all cells serve as a highly conserved, information-bearing pathway that regulates cell proliferation, migration and differentiation. In embryonic and regenerative pattern formation and in the disorganization of neoplasia, bioelectrical cues serve as mediators of large-scale anatomical polarity, organ identity and positional information. Recent developments have resulted in tools that enable a high-resolution analysis of these biophysical signals and their linkage with upstream and downstream canonical genetic pathways. Here, we provide an overview for the study of bioelectric signaling, focusing on state-of-the-art approaches that use molecular physiology and developmental genetics to probe the roles of bioelectric events functionally. We highlight the logic, strategies and well-developed technologies that any group of researchers can employ to identify and dissect ionic signaling components in their own work and thus to help crack the bioelectric code. The dissection of bioelectric events as instructive signals enabling the orchestration of cell behaviors into large-scale coherent patterning programs will enrich on-going work in diverse areas of biology, as biophysical factors become incorporated into our systems-level understanding of cell interactions.
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Affiliation(s)
- Dany S Adams
- Department of Biology, and Center for Regenerative and Developmental Biology, Tufts University, 200 Boston Ave, Medford, MA 02155, USA
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Yasuda T, Cuny H, Adams DJ. Kv3.1 channels stimulate adult neural precursor cell proliferation and neuronal differentiation. J Physiol 2013; 591:2579-91. [PMID: 23478135 DOI: 10.1113/jphysiol.2012.249151] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Adult neural stem/precursor cells (NPCs) play a pivotal role in neuronal plasticity throughout life. Among ion channels identified in adult NPCs, voltage-gated delayed rectifier K(+) (KDR) channels are dominantly expressed. However, the KDR channel subtype and its physiological role are still undefined. We used real-time quantitative RT-PCR and gene knockdown techniques to identify a major functional KDR channel subtype in adult NPCs. Dominant mRNA expression of Kv3.1, a high voltage-gated KDR channel, was quantitatively confirmed. Kv3.1 gene knockdown with specific small interfering RNAs (siRNA) for Kv3.1 significantly inhibited Kv3.1 mRNA expression by 63.9% (P < 0.001) and KDR channel currents by 52.2% (P < 0.001). This indicates that Kv3.1 is the subtype responsible for producing KDR channel outward currents. Resting membrane properties, such as resting membrane potential, of NPCs were not affected by Kv3.1 expression. Kv3.1 knockdown with 300 nm siRNA inhibited NPC growth (increase in cell numbers) by 52.9% (P < 0.01). This inhibition was attributed to decreased cell proliferation, not increased cell apoptosis. We also established a convenient in vitro imaging assay system to evaluate NPC differentiation using NPCs from doublecortin-green fluorescent protein transgenic mice. Kv3.1 knockdown also significantly reduced neuronal differentiation by 31.4% (P < 0.01). We have demonstrated that Kv3.1 is a dominant functional KDR channel subtype expressed in adult NPCs and plays key roles in NPC proliferation and neuronal lineage commitment during differentiation.
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Affiliation(s)
- Takahiro Yasuda
- Center for Clinical Research, School of Medicine, Kobe University Hospital, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
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Ca2+ activated K channels-new tools to induce cardiac commitment from pluripotent stem cells in mice and men. Stem Cell Rev Rep 2012; 8:720-40. [PMID: 22038332 DOI: 10.1007/s12015-011-9324-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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The dynactin p150 subunit: cell biology studies of sequence changes found in ALS/MND and Parkinsonian Syndromes. J Neural Transm (Vienna) 2012; 120:785-98. [DOI: 10.1007/s00702-012-0910-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 10/20/2012] [Indexed: 01/11/2023]
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Bioelectric state and cell cycle control of Mammalian neural stem cells. Stem Cells Int 2012; 2012:816049. [PMID: 23024660 PMCID: PMC3447385 DOI: 10.1155/2012/816049] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 07/22/2012] [Indexed: 12/25/2022] Open
Abstract
The concerted action of ion channels and pumps establishing a resting membrane potential has been most thoroughly studied in the context of excitable cells, most notably neurons, but emerging evidences indicate that they are also involved in controlling proliferation and differentiation of nonexcitable somatic stem cells. The importance of understanding stem cell contribution to tissue formation during embryonic development, adult homeostasis, and regeneration in disease has prompted many groups to study and manipulate the membrane potential of stem cells in a variety of systems. In this paper we aimed at summarizing the current knowledge on the role of ion channels and pumps in the context of mammalian corticogenesis with particular emphasis on their contribution to the switch of neural stem cells from proliferation to differentiation and generation of more committed progenitors and neurons, whose lineage during brain development has been recently elucidated.
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Heinrich J, Proepper C, Schmidt T, Linta L, Liebau S, Boeckers TM. The postsynaptic density protein Abelson interactor protein 1 interacts with the motor protein Kinesin family member 26B in hippocampal neurons. Neuroscience 2012; 221:86-95. [PMID: 22766233 DOI: 10.1016/j.neuroscience.2012.06.055] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 06/22/2012] [Accepted: 06/23/2012] [Indexed: 11/24/2022]
Abstract
Abelson interactor protein 1 (Abi-1) localizes to postsynaptic densities (PSDs) of excitatory synapses and was shown to be transported from the PSD to the nucleus and back depending upon synaptic activation. We employed a yeast-two-hybrid screen to search for putative transport molecules. We found Kif26B a member of the Kif family of transport proteins that has not been characterized in the central nervous system as a direct interaction partner of Abi-1. We delineated a proline-rich motif within the cargo-binding domain of Kif26B to be responsible for this protein-protein interaction. Kif26B was able to recruit Abi-1 to the microtubule network and we found that the expression of Kif26B is responsible for the localization of Abi-1 to PSDs in maturing neurons. Taken together we report that Abi-1 is a cargo of Kif26B in primary hippocampal neurons, pointing to a role of this transport molecule in the movement of Abi-1 between different cell compartments. Additionally, we provide the first detailed investigation of Kif26B and its cargo molecules in neuronal cells.
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Affiliation(s)
- J Heinrich
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
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28
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He XB, Yi SH, Rhee YH, Kim H, Han YM, Lee SH, Lee H, Park CH, Lee YS, Richardson E, Kim BW, Lee SH. Prolonged membrane depolarization enhances midbrain dopamine neuron differentiation via epigenetic histone modifications. Stem Cells 2012; 29:1861-73. [PMID: 21922608 DOI: 10.1002/stem.739] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Understanding midbrain dopamine (DA) neuron differentiation is of importance, because of physiological and clinical implications of this neuronal subtype. We show that prolonged membrane depolarization induced by KCl treatment promotes DA neuron differentiation from neural precursor cells (NPCs) derived from embryonic ventral midbrain (VM). Interestingly, the depolarization-induced increase of DA neuron yields was not abolished by L-type calcium channel blockers, along with no depolarization-mediated change of intracellular calcium level in the VM-derived NPCs (VM-NPCs), suggesting that the depolarization effect is due to a calcium-independent mechanism. Experiments with labeled DA neuron progenitors indicate that membrane depolarization acts at the differentiation fate determination stage and promotes the expression of DA phenotype genes (tyrosine hydroxylase [TH] and DA transporter [DAT]). Recruitment of Nurr1, a transcription factor crucial for midbrain DA neuron development, to the promoter of TH gene was enhanced by depolarization, along with increases of histone 3 acetylation (H3Ac) and trimethylation of histone3 on lysine 4 (H3K4m3), and decreases of H3K9m3 and H3K27m3 in the consensus Nurr1 binding regions of TH promoter. Depolarization stimuli on differentiating VM-NPCs also induced dissociation of methyl CpG binding protein 2 and related repressor complex molecules (repressor element-1 silencing transcription factor corepressor and histone deacetylase 1) from the CpG sites of TH and DAT promoters. Based on these findings, we suggest that membrane depolarization promotes DA neuron differentiation by opening chromatin structures surrounding DA phenotype genes and inhibiting the binding of corepressors, thus allowing transcriptional activators such as Nurr1 to access DA neuron differentiation gene promoter regions.
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Affiliation(s)
- Xi-Biao He
- Department of Biochemistry and Molecular Biology, College of Medicine, Hanyang University, Seoul, Korea
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29
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Lioudyno MI, Broccio M, Sokolov Y, Rasool S, Wu J, Alkire MT, Liu V, Kozak JA, Dennison PR, Glabe CG, Lösche M, Hall JE. Effect of synthetic aβ peptide oligomers and fluorinated solvents on Kv1.3 channel properties and membrane conductance. PLoS One 2012; 7:e35090. [PMID: 22563377 PMCID: PMC3338507 DOI: 10.1371/journal.pone.0035090] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 03/12/2012] [Indexed: 01/07/2023] Open
Abstract
The impact of synthetic amyloid β (1–42) (Aβ1–42) oligomers on biophysical properties of voltage-gated potassium channels Kv 1.3 and lipid bilayer membranes (BLMs) was quantified for protocols using hexafluoroisopropanol (HFIP) or sodium hydroxide (NaOH) as solvents prior to initiating the oligomer formation. Regardless of the solvent used Aβ1–42 samples contained oligomers that reacted with the conformation-specific antibodies A11 and OC and had similar size distributions as determined by dynamic light scattering. Patch-clamp recordings of the potassium currents showed that synthetic Aβ1–42 oligomers accelerate the activation and inactivation kinetics of Kv 1.3 current with no significant effect on current amplitude. In contrast to oligomeric samples, freshly prepared, presumably monomeric, Aβ1–42 solutions had no effect on Kv 1.3 channel properties. Aβ1–42 oligomers had no effect on the steady-state current (at −80 mV) recorded from Kv 1.3-expressing cells but increased the conductance of artificial BLMs in a dose-dependent fashion. Formation of amyloid channels, however, was not observed due to conditions of the experiments. To exclude the effects of HFIP (used to dissolve lyophilized Aβ1–42 peptide), and trifluoroacetic acid (TFA) (used during Aβ1–42 synthesis), we determined concentrations of these fluorinated compounds in the stock Aβ1–42 solutions by 19F NMR. After extensive evaporation, the concentration of HFIP in the 100× stock Aβ1–42 solutions was ∼1.7 μM. The concentration of residual TFA in the 70× stock Aβ1–42 solutions was ∼20 μM. Even at the stock concentrations neither HFIP nor TFA alone had any effect on potassium currents or BLMs. The Aβ1–42 oligomers prepared with HFIP as solvent, however, were more potent in the electrophysiological tests, suggesting that fluorinated compounds, such as HFIP or structurally-related inhalational anesthetics, may affect Aβ1–42 aggregation and potentially enhance ability of oligomers to modulate voltage-gated ion channels and biological membrane properties.
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Affiliation(s)
- Maria I. Lioudyno
- Department of Physiology and Biophysics, University of California Irvine, Irvine, Calfornia, United States of America
| | - Matteo Broccio
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Yuri Sokolov
- Department of Physiology and Biophysics, University of California Irvine, Irvine, Calfornia, United States of America
| | - Suhail Rasool
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California, United States of America
| | - Jessica Wu
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California, United States of America
| | - Michael T. Alkire
- Department of Anesthesiology and Perioperative Care, University of California Irvine, Irvine, California, United States of America
| | - Virginia Liu
- Department of Physiology and Biophysics, University of California Irvine, Irvine, Calfornia, United States of America
- Department of Anesthesiology and Perioperative Care, University of California Irvine, Irvine, California, United States of America
| | - J. Ashot Kozak
- Department of Neuroscience, Cell biology, and Physiology, Wright State University, Dayton, Ohio, United States of America
| | - Philip R. Dennison
- Department of Chemistry, University of California Irvine, Irvine, California, United States of America
| | - Charles G. Glabe
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California, United States of America
| | - Mathias Lösche
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - James E. Hall
- Department of Physiology and Biophysics, University of California Irvine, Irvine, Calfornia, United States of America
- * E-mail:
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The potential of iPS cells in synucleinopathy research. Stem Cells Int 2012; 2012:629230. [PMID: 22550513 PMCID: PMC3329650 DOI: 10.1155/2012/629230] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 01/12/2012] [Indexed: 11/17/2022] Open
Abstract
α-synuclein is a protein involved in the pathogenesis of several so-called synucleinopathies including Parkinson's disease. A variety of models have been so far assessed. Human induced pluripotent stem cells provide a patient- and disease-specific model for in vitro studies, pharmacotoxicological screens, and hope for future cell-based therapies. Initial experimental procedures include the harvest of patients' material for the reprogramming process, the investigation of the patients genetic background in the cultured cells, and the evaluation of disease-relevant factors/proteins under various cell culture conditions.
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Levin M, Stevenson CG. Regulation of cell behavior and tissue patterning by bioelectrical signals: challenges and opportunities for biomedical engineering. Annu Rev Biomed Eng 2012; 14:295-323. [PMID: 22809139 PMCID: PMC10472538 DOI: 10.1146/annurev-bioeng-071811-150114] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Achieving control over cell behavior and pattern formation requires molecular-level understanding of regulatory mechanisms. Alongside transcriptional networks and biochemical gradients, there functions an important system of cellular communication and control: transmembrane voltage gradients (V(mem)). Bioelectrical signals encoded in spatiotemporal changes of V(mem) control cell proliferation, migration, and differentiation. Moreover, endogenous bioelectrical gradients serve as instructive cues mediating anatomical polarity and other organ-level aspects of morphogenesis. In the past decade, significant advances in molecular physiology have enabled the development of new genetic and biophysical tools for the investigation and functional manipulation of bioelectric cues. Recent data implicate V(mem) as a crucial epigenetic regulator of patterning events in embryogenesis, regeneration, and cancer. We review new conceptual and methodological developments in this fascinating field. Bioelectricity offers a novel way of quantitatively understanding regulation of growth and form in vivo, and it reveals tractable, powerful control points that will enable truly transformative applications in bioengineering, regenerative medicine, and synthetic biology.
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Affiliation(s)
- Michael Levin
- Department of Biology, Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts 02155, USA.
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32
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Proepper C, Steinestel K, Schmeisser MJ, Heinrich J, Steinestel J, Bockmann J, Liebau S, Boeckers TM. Heterogeneous nuclear ribonucleoprotein k interacts with Abi-1 at postsynaptic sites and modulates dendritic spine morphology. PLoS One 2011; 6:e27045. [PMID: 22102872 PMCID: PMC3216941 DOI: 10.1371/journal.pone.0027045] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 10/09/2011] [Indexed: 12/31/2022] Open
Abstract
Background Abelson-interacting protein 1 (Abi-1) plays an important role for dendritic branching and synapse formation in the central nervous system. It is localized at the postsynaptic density (PSD) and rapidly translocates to the nucleus upon synaptic stimulation. At PSDs Abi-1 is in a complex with several other proteins including WASP/WAVE or cortactin thereby regulating the actin cytoskeleton via the Arp 2/3 complex. Principal Findings We identified heterogeneous nuclear ribonucleoprotein K (hnRNPK), a 65 kDa ssDNA/RNA-binding-protein that is involved in multiple intracellular signaling cascades, as a binding partner of Abi-1 at postsynaptic sites. The interaction with the Abi-1 SH3 domain is mediated by the hnRNPK-interaction (KI) domain. We further show that during brain development, hnRNPK expression becomes more and more restricted to granule cells of the cerebellum and hippocampal neurons where it localizes in the cell nucleus as well as in the spine/dendritic compartment. The downregulation of hnRNPK in cultured hippocampal neurons by RNAi results in an enlarged dendritic tree and a significant increase in filopodia formation. This is accompanied by a decrease in the number of mature synapses. Both effects therefore mimic the neuronal morphology after downregulation of Abi-1 mRNA in neurons. Conclusions Our findings demonstrate a novel interplay between hnRNPK and Abi-1 in the nucleus and at synaptic sites and show obvious similarities regarding both protein knockdown phenotypes. This indicates that hnRNPK and Abi-1 act synergistic in a multiprotein complex that regulates the crucial balance between filopodia formation and synaptic maturation in neurons.
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Affiliation(s)
| | - Konrad Steinestel
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
- Department of Pathology, BWK Hospital Ulm, Ulm, Germany
| | | | - Jutta Heinrich
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Julie Steinestel
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Juergen Bockmann
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Stefan Liebau
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
- * E-mail: (TMB); (SL)
| | - Tobias M. Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
- * E-mail: (TMB); (SL)
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33
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Liebau S, Tischendorf M, Ansorge D, Linta L, Stockmann M, Weidgang C, Iacovino M, Boeckers T, von Wichert G, Kyba M, Kleger A. An inducible expression system of the calcium-activated potassium channel 4 to study the differential impact on embryonic stem cells. Stem Cells Int 2011; 2011:456815. [PMID: 21941566 PMCID: PMC3173888 DOI: 10.4061/2011/456815] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 06/14/2011] [Indexed: 11/20/2022] Open
Abstract
Rationale. The family of calcium-activated potassium channels consists of four members with varying biological functions and conductances. Besides membrane potential modulation, SK channels have been found to be involved in cardiac pacemaker cell development from ES cells and morphological shaping of neural stem cells. Objective. Distinct SK channel subtype expression in ES cells might elucidate their precise impact during cardiac development. We chose SK channel subtype 4 as a potential candidate influencing embryonic stem cell differentiation. Methods. We generated a doxycycline inducible mouse ES cell line via targeted homologous recombination of a cassette expressing a bicistronic construct encoding SK4 and a fluorophore from the murine HPRT locus. Conclusion. We characterized the mouse ES cell line iSK4-AcGFP. The cassette is readily expressed under the control of doxycycline, and the overexpression of SK4 led to an increase in cardiac and pacemaker cell differentiation thereby serving as a unique tool to characterize the cell biological variances due to specific SK channel overexpression.
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Affiliation(s)
- Stefan Liebau
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
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34
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Boda E, Hoxha E, Pini A, Montarolo F, Tempia F. Brain expression of Kv3 subunits during development, adulthood and aging and in a murine model of Alzheimer's disease. J Mol Neurosci 2011; 46:606-15. [PMID: 21912965 DOI: 10.1007/s12031-011-9648-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 09/01/2011] [Indexed: 12/17/2022]
Abstract
In neurons, voltage-dependent Kv3 potassium channels are essential for the generation of action potentials at high frequency. A dysregulation of the Kv3.1 and Kv3.4 channel subunits has been suggested to contribute to neuronal and glial alterations in Alzheimer's disease, but a quantitative evaluation of these subunits in a mouse model of the pathology is still lacking. We analysed the profile of expression of the four Kv3 subunits by quantitative reverse transcription PCR and Western blot in the whole mouse brain and in dissected brain regions (olfactory bulb, septum, neocortex, hippocampus, brainstem and cerebellum) from 14 days after conception to 18 months after birth. In addition, we measured the levels of Kv3.1 and Kv3.4 messenger RNAs (mRNAs) and proteins in neocortex and hippocampus of APPPS1 mice, a transgenic model of Alzheimer's disease. Although all Kv3 transcripts were significantly expressed in embryonic age in whole brain extracts, only Kv3.1, Kv3.2 and Kv3.4 subunit proteins were present, suggesting a novel role for Kv3 channels at this developmental stage. With the exception of Kv3.4, during postnatal development, Kv3 transcripts and proteins showed a progressive increase in expression and reached an asymptote in adulthood, suggesting that the increase in Kv3 expression during development might contribute to the maturation of the electrical activity of neurons. During aging, Kv3 expression was rather stable. In contrast, in the neocortex of aged APPPS1 mice, Kv3.1 mRNA and protein levels were significantly lower compared to wild type, suggesting that a decrease in Kv3 currents could play a role in the cognitive symptoms of Alzheimer's disease.
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Affiliation(s)
- Enrica Boda
- Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, Regione Gonzole, 10, Orbassano, 10043, Turin, Italy
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Xi G, Zhang X, Zhang L, Sui Y, Hui J, Liu S, Wang Y, Li L, Zhang Z. Fluoxetine attenuates the inhibitory effect of glucocorticoid hormones on neurogenesis in vitro via a two-pore domain potassium channel, TREK-1. Psychopharmacology (Berl) 2011; 214:747-59. [PMID: 21069514 DOI: 10.1007/s00213-010-2077-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 10/27/2010] [Indexed: 01/17/2023]
Abstract
RATIONALE Sustained stress and elevated glucocorticoid reduces neurogenesis, whereas chronic treatment with antidepressants increases neurogenesis and blocks the effects of stress. Recently, TREK-1, a two-pore domain (K(2)p) potassium channel, has been shown to be involved in the mechanisms of major depression. OBJECTIVES This study aimed to investigate whether TREK-1 is involved in the alteration of neurogenesis according to glucocorticoids and antidepressants. RESULTS The present study addressed the expression of TREK-1 in neural stem cells (NSCs) and found TREK-1 was only associated with NSC proliferation. Bupivacaine and curcumin, two strong TREK-1 channel inhibitors, significantly increased embryonic NSC viability and proliferation while transfection of hTREK-1 decreased cell proliferation in embryonic NSCs. Dexamethasone, a glucocorticoid hormone receptor agonist, upregulated both protein and mRNA levels of TREK-1 leading to decreased NSC proliferation which could be reversed by bupivacaine. Fluoxetine, a serotonin reuptake inhibitor antidepressant that has been previously found to inhibit TREK-1 channels, robustly, could attenuate the upregulation of TREK-1 expression and the inhibition of NSC proliferation induced by dexamethasone. CONCLUSIONS Taken together, these data suggest that TREK-1 is associated with NSC proliferation and probably is a modulator of the effect that fluoxetine attenuates the inhibitory neurogenesis induced by glucocorticoid hormones.
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Affiliation(s)
- Guangjun Xi
- The Department of Neurology, Affiliated Zhongda Hospital of Southeast University, Nanjing, 210009, China
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36
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Li GR, Deng XL. Functional ion channels in stem cells. World J Stem Cells 2011; 3:19-24. [PMID: 21607133 PMCID: PMC3097936 DOI: 10.4252/wjsc.v3.i3.19] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Revised: 01/14/2011] [Accepted: 01/21/2011] [Indexed: 02/06/2023] Open
Abstract
Bioelectrical signals generated by ion channels play crucial roles in excitation genesis and impulse conduction in excitable cells as well as in cell proliferation, migration and apoptosis in proliferative cells. Recent studies have demonstrated that multiple ion channels are heterogeneously present in different stem cells; however, patterns and phenotypes of ion channels are species- and/or origin-dependent. This editorial review focuses on the recent findings related to the expression of functional ion channels and the roles of these channels in regulation of cell proliferation in stem cells. Additional effort is required in the future to clarify the ion channel expression in different types of stem cells; special attention should be paid to the relationship between ion channels and stem cell proliferation, migration and differentiation.
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Affiliation(s)
- Gui-Rong Li
- Gui-Rong Li, Departments of Medicine and Physiology, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong, China
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37
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Potassium channel expression in adult murine neural progenitor cells. Neuroscience 2011; 180:19-29. [PMID: 21329741 DOI: 10.1016/j.neuroscience.2011.02.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 01/08/2011] [Accepted: 02/08/2011] [Indexed: 11/21/2022]
Abstract
Neural progenitor cells (NPCs) are a source of new neurons and glia in the adult brain. Most NPCs reside in the forebrain subventricular zone (SVZ) and in the subgranular zone of the dentate gyrus, where they contribute to plasticity in the adult brain. To use their potential for repair, it is essential to identify the molecules that regulate their growth, migration and differentiation. Potassium (K+) channels are promising molecule candidates for NPC regulation as they are important components of signal transduction and their diversity is ideal to cover the complex functions required for cell proliferation and differentiation. There is increasing evidence that K+ channels influence cell growth and neurogenesis, however, very little is known regarding K+ channel distribution in NPCs. We therefore explored the expression of a variety of voltage-gated (Kv), inwardly rectifying (Kir) and two-pore (K2P) K+ channels in the SVZ of adult mice and in neurosphere cultures of NPCs during growth and differentiation. Immunocytochemical analysis revealed a differential expression pattern of K+ channels in nestin+ SVZ precursor cells, early SVZ doublecortin+ neurons and (sub)ependymal cells. These findings were confirmed in neurosphere cultures at the protein and mRNA levels. The expression of some K+ channel proteins, such as Kir4.1, Kir6.1, TREK1 or TASK1, suggests a role of K+ channels in the complex regulation of NPC proliferation, maturation and differentiation.
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A novel role for Kv1.3 blockers: protecting neural progenitor cells from a hostile inflammatory environment. J Neurosci 2010; 30:10609-11. [PMID: 20702693 DOI: 10.1523/jneurosci.2802-10.2010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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39
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Pacemaker currents in mouse locus coeruleus neurons. Neuroscience 2010; 170:166-77. [DOI: 10.1016/j.neuroscience.2010.06.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 06/09/2010] [Accepted: 06/12/2010] [Indexed: 11/18/2022]
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40
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Swayne LA, Sorbara CD, Bennett SAL. Pannexin 2 is expressed by postnatal hippocampal neural progenitors and modulates neuronal commitment. J Biol Chem 2010; 285:24977-86. [PMID: 20529862 DOI: 10.1074/jbc.m110.130054] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The pannexins (Panx1, -2, and -3) are a mammalian family of putative single membrane channels discovered through homology to invertebrate gap junction-forming proteins, the innexins. Because connexin gap junction proteins are known regulators of neural stem and progenitor cell proliferation, migration, and specification, we asked whether pannexins, specifically Panx2, play a similar role in the postnatal hippocampus. We show that Panx2 protein is differentially expressed by multipotential progenitor cells and mature neurons. Both in vivo and in vitro, Type I and IIa stem-like neural progenitor cells express an S-palmitoylated Panx2 species localizing to Golgi and endoplasmic reticulum membranes. Protein expression is down-regulated during neurogenesis in neuronally committed Type IIb and III progenitor cells and immature neurons. Panx2 is re-expressed by neurons following maturation. Protein expressed by mature neurons is not palmitoylated and localizes to the plasma membrane. To assess the impact of Panx2 on neuronal differentiation, we used short hairpin RNA to suppress Panx2 expression in Neuro2a cells. Knockdown significantly accelerated the rate of neuronal differentiation. Neuritic extension and the expression of antigenic markers of mature neurons occurred earlier in stable lines expressing Panx2 short hairpin RNA than in controls. Together, these findings describe an endogenous post-translational regulation of Panx2, specific to early neural progenitor cells, and demonstrate that this expression plays a role in modulating the timing of their commitment to a neuronal lineage.
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Affiliation(s)
- Leigh Anne Swayne
- Department of Biochemistry, Neural Regeneration Laboratory and Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario K1M 1E5, Canada.
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Ng SY, Chin CH, Lau YT, Luo J, Wong CK, Bian ZX, Tsang SY. Role of voltage-gated potassium channels in the fate determination of embryonic stem cells. J Cell Physiol 2010; 224:165-77. [PMID: 20333647 DOI: 10.1002/jcp.22113] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Embryonic stem cells (ESCs) possess two unique characteristics: self-renewal and pluripotency. In this study, roles of voltage-gated potassium channels (K(v)) in maintaining mouse (m) ESC characteristics were investigated. Tetraethylammonium (TEA(+)), a K(v) blocker, attenuated cell proliferation in a concentration-dependent manner. Possible reasons for this attenuation, including cytotoxicity, cell cycle arrest and differentiation, were examined. Blocking K(v) did not change the viability of mESCs. Interestingly, K(v) inhibition increased the proportion of cells in G(0)/G(1) phase and decreased that in S phase. This change in cell cycle distribution can be attributed to cell cycle arrest or differentiation. Loss of pluripotency as determined at both molecular and functional levels was detected in mESCs with K(v) blockade, indicating that K(v) inhibition in undifferentiated mESCs directs cells to differentiate instead of to self-renew and progress through the cell cycle. Membrane potential measurement revealed that K(v) blockade led to depolarization, consistent with the role of K(v) as the key determinant of membrane potential. The present results suggest that membrane potential changes may act as a "switch" for ESCs to decide whether to proliferate or to differentiate: hyperpolarization at G(1) phase would favor ESCs to enter S phase while depolarization would favor ESCs to differentiate. Consistent with this notion, S-phase-synchronized mESCs were found to be more hyperpolarized than G(0)/G(1)-phase-synchronized mESCs. Moreover, when mESCs differentiated, the differentiation derivatives depolarized at the initial stage of differentiation. This investigation is the first study to provide evidence that K(v) and membrane potential affect the fate determination of ESCs.
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Affiliation(s)
- Sze-Ying Ng
- Department of Biochemistry, The Chinese University of Hong Kong, Hong Kong, China
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Yasuda T, Adams DJ. Physiological roles of ion channels in adult neural stem cells and their progeny. J Neurochem 2010; 114:946-59. [PMID: 20492359 DOI: 10.1111/j.1471-4159.2010.06822.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Elucidation of the machinery of adult neurogenesis is indispensable for the treatment of neurodegenerative diseases by therapeutic drugs and/or by neural stem cell (NSC) transplantation. It is well known that membrane ion channels play a critical role in cell function, including proliferation, apoptosis and migration in a wide range of cells. In NSC research, interdisciplinary collaboration between cell biologists and membrane physiologists has been pursued principally to monitor ion channel and synaptic currents as a hallmark of neuronal differentiation and maturation of NSC progeny. Nevertheless, less attention had been paid to a functional role of ion channels in NSCs or their immature progeny. Recently, however, evidence regarding their functional relevance has started to accumulate. In focusing on the early stages of the neurogenic process during which NSCs give rise to neuroblasts, this review highlights the latent ability of ion channels to act as functional regulators of adult neurogenesis.
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Affiliation(s)
- Takahiro Yasuda
- Health Innovations Research Institute, RMIT University, Melbourne, Victoria, Australia.
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Lai B, Mao XO, Xie L, Chang SY, Xiong ZG, Jin K, Greenberg DA. Electrophysiological properties of subventricular zone cells in adult mouse brain. Brain Res 2010; 1340:96-105. [PMID: 20434436 DOI: 10.1016/j.brainres.2010.04.057] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 04/20/2010] [Accepted: 04/22/2010] [Indexed: 01/15/2023]
Abstract
The subventricular zone (SVZ) is a principal site of adult neurogenesis and appears to participate in the brain's response to injury. Thus, measures that enhance SVZ neurogenesis may have a role in treatment of neurological disease. To better characterize SVZ cells and identify potential targets for therapeutic intervention, we studied electrophysiological properties of SVZ cells in adult mouse brain slices using patch-clamp techniques. Electrophysiology was correlated with immunohistochemical phenotype by injecting cells with lucifer yellow and by studying transgenic mice carrying green fluorescent protein under control of the doublecortin (DCX) or glial fibrillary acidic protein (GFAP) promoter. We identified five types of cells in the adult mouse SVZ: type 1 cells, with 4-aminopyridine (4-AP)/tetraethylammonium (TEA)-sensitive and CdCl(2)-sensitive inward currents; type 2 cells, with Ca(2+)-sensitive K(+) and both 4-AP/TEA-sensitive and -insensitive currents; type 3 cells, with 4-AP/TEA-sensitive and -insensitive K(+) and small Na(+) currents; type 4 cells, with slowly activating, large linear outward current and sustained outward current without fast-inactivating component; and type 5 cells, with a large outward rectifying current with a fast inactivating component. Type 2 and 3 cells expressed DCX, types 4 and 5 cells expressed GFAP, and type 1 cells expressed neither. We propose that SVZ neurogenesis involves a progression of electrophysiological cell phenotypes from types 4 and 5 cells (astrocytes) to type 1 cells (neuronal progenitors) to types 2 and 3 cells (nascent neurons), and that drugs acting on ion channels expressed during neurogenesis might promote therapeutic neurogenesis in the injured brain.
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Affiliation(s)
- Bin Lai
- Buck Institute for Age Research, 8001 Redwood Boulevard, Novato, California 94945, USA
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Abstract
There is a great need for pharmacological approaches to enhance neural progenitor cell (NPC) function particularly in neuroinflammatory diseases with failed neuroregeneration. In diseases such as multiple sclerosis and stroke, T-cell infiltration occurs in periventricular zones where NPCs are located and is associated with irreversible neuronal loss. We studied the effect of T-cell activation on NPC functions. NPC proliferation and neuronal differentiation were impaired by granzyme B (GrB) released by the T-cells. GrB mediated its effects by the activation of a Gi-protein-coupled receptor leading to decreased intracellular levels of cAMP and subsequent expression of the voltage-dependent potassium channel, Kv1.3. Importantly, blocking channel activity with margatoxin or blocking its expression reversed the inhibitory effects of GrB on NPCs. We have thus identified a novel pathway in neurogenesis. The increased expression of Kv1.3 in pathological conditions makes it a novel target for promoting neurorestoration.
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45
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TRPV2 enhances axon outgrowth through its activation by membrane stretch in developing sensory and motor neurons. J Neurosci 2010; 30:4601-12. [PMID: 20357111 DOI: 10.1523/jneurosci.5830-09.2010] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Thermosensitive TRP (thermo TRP) channels are well recognized for their contributions to sensory transduction, responding to a wide variety of stimuli including temperature, nociceptive stimuli, touch, and osmolarity. However, the precise roles for the thermo TRP channels during development have not been determined. To explore the functional importance of thermo TRP channels during neural development, the temporal expression was determined in embryonic mice. Interestingly, TRPV2 expression was detected in spinal motor neurons in addition to the dorsal root ganglia from embryonic day 10.5 and was localized in axon shafts and growth cones, suggesting that the channel is important for axon outgrowth regulation. We revealed that endogenous TRPV2 was activated in a membrane stretch-dependent manner in developing neurons by knocking down the TRPV2 function with dominant-negative TRPV2 and TRPV2-specific shRNA and significantly promoted axon outgrowth. Thus, for the first time we revealed that TRPV2 is an important regulator for axon outgrowth through its activation by membrane stretch during development.
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Muth-Köhne E, Terhag J, Pahl S, Werner M, Joshi I, Hollmann M. Functional excitatory GABAA receptors precede ionotropic glutamate receptors in radial glia-like neural stem cells. Mol Cell Neurosci 2009; 43:209-21. [PMID: 19931619 DOI: 10.1016/j.mcn.2009.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 11/10/2009] [Accepted: 11/12/2009] [Indexed: 12/21/2022] Open
Abstract
The involvement of neurotransmission in neuronal development is a generally accepted concept. Nevertheless, the precise regulation of neurotransmitter receptor expression is still unclear. To investigate the expression profiles of the most important ionotropic neurotransmitter receptors, namely GABA(A) receptors (GABA(A)Rs), NMDA receptors (NMDARs), and AMPA receptors (AMPARs), quantitative RT-PCR, immunoblot analysis and patch clamp studies were performed in in vitro-generated neural stem cells (NSCs). This clearly defined cell line is closely related to radial glia cells, the stem cells in the neonate brain. We found functional GABA(A)Rs of the subunit composition alpha2, beta3, and gamma1 to be expressed. Unexpectedly, functional ionotropic glutamate receptors were absent. However, NSCs expressed the NMDAR subunits NR2A and NR3A, and the AMPAR subunit GluR4 at the protein level, and GluR3 at the mRNA level. The overexpression of functional NMDARs in NSCs led to an increased mRNA level of AMPAR subunits, indicating a role in synaptogenesis. Early neuronal markers remained unchanged. These data extend our knowledge about ionotropic neurotransmitter receptor expression during neuronal development and will aid further investigations on activity-dependent neurogenesis.
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Affiliation(s)
- Elke Muth-Köhne
- Department of Biochemistry I-Receptor Biochemistry, Ruhr University Bochum, D-44780 Bochum, Germany
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Schaarschmidt G, Wegner F, Schwarz SC, Schmidt H, Schwarz J. Characterization of voltage-gated potassium channels in human neural progenitor cells. PLoS One 2009; 4:e6168. [PMID: 19584922 PMCID: PMC2702754 DOI: 10.1371/journal.pone.0006168] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 06/03/2009] [Indexed: 12/30/2022] Open
Abstract
Background Voltage-gated potassium (Kv) channels are among the earliest ion channels to appear during brain development, suggesting a functional requirement for progenitor cell proliferation and/or differentiation. We tested this hypothesis, using human neural progenitor cells (hNPCs) as a model system. Methodology/Principal Findings In proliferating hNPCs a broad spectrum of Kv channel subtypes was identified using quantitative real-time PCR with a predominant expression of the A-type channel Kv4.2. In whole-cell patch-clamp recordings Kv currents were separated into a large transient component characteristic for fast-inactivating A-type potassium channels (IA) and a small, sustained component produced by delayed-rectifying channels (IK). During differentiation the expression of IA as well as A-type channel transcripts dramatically decreased, while IK producing delayed-rectifiers were upregulated. Both Kv currents were differentially inhibited by selective neurotoxins like phrixotoxin-1 and α-dendrotoxin as well as by antagonists like 4-aminopyridine, ammoniumchloride, tetraethylammonium chloride and quinidine. In viability and proliferation assays chronic inhibition of the A-type currents severely disturbed the cell cycle and precluded proper hNPC proliferation, while the blockade of delayed-rectifiers by α-dendrotoxin increased proliferation. Conclusions/Significance These findings suggest that A-type potassium currents are essential for proper proliferation of immature multipotent hNPCs.
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Levin M. Bioelectric mechanisms in regeneration: Unique aspects and future perspectives. Semin Cell Dev Biol 2009; 20:543-56. [PMID: 19406249 DOI: 10.1016/j.semcdb.2009.04.013] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Accepted: 04/22/2009] [Indexed: 01/14/2023]
Abstract
Regenerative biology has focused largely on chemical factors and transcriptional networks. However, endogenous ion flows serve as key epigenetic regulators of cell behavior. Bioelectric signaling involves feedback loops, long-range communication, polarity, and information transfer over multiple size scales. Understanding the roles of endogenous voltage gradients, ion flows, and electric fields will contribute to the basic understanding of numerous morphogenetic processes and the means by which they can robustly restore pattern after perturbation. By learning to modulate the bioelectrical signals that control cell proliferation, migration, and differentiation, we gain a powerful set of new techniques with which to manipulate growth and patterning in biomedical contexts. This chapter reviews the unique properties of bioelectric signaling, surveys molecular strategies and reagents for its investigation, and discusses the opportunities made available for regenerative medicine.
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Affiliation(s)
- Michael Levin
- Tufts Center for Regenerative and Developmental Biology, Biology Department, Tufts University, Medford, MA 02155, USA.
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Characterization of Excitability and Voltage-gated Ion Channels of Neural Progenitor Cells in Rat Hippocampus. J Mol Neurosci 2008; 35:289-95. [DOI: 10.1007/s12031-008-9065-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 03/13/2008] [Indexed: 10/22/2022]
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Smith DO, Rosenheimer JL, Kalil RE. Delayed rectifier and A-type potassium channels associated with Kv 2.1 and Kv 4.3 expression in embryonic rat neural progenitor cells. PLoS One 2008; 3:e1604. [PMID: 18270591 PMCID: PMC2225502 DOI: 10.1371/journal.pone.0001604] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 01/21/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Because of the importance of voltage-activated K(+) channels during embryonic development and in cell proliferation, we present here the first description of these channels in E15 rat embryonic neural progenitor cells derived from the subventricular zone (SVZ). Activation, inactivation, and single-channel conductance properties of recorded progenitor cells were compared with those obtained by others when these Kv gene products were expressed in oocytes. METHODOLOGY/PRINCIPAL FINDINGS Neural progenitor cells derived from the subventricular zone of E15 embryonic rats were cultured under conditions that did not promote differentiation. Immunocytochemical and Western blot assays for nestin expression indicated that almost all of the cells available for recording expressed this intermediate filament protein, which is generally accepted as a marker for uncommitted embryonic neural progenitor cells. However, a very small numbers of the cells expressed GFAP, a marker for astrocytes, O4, a marker for immature oligodendrocytes, and betaIII-tubulin, a marker for neurons. Using immunocytochemistry and Western blots, we detected consistently the expression of Kv2.1, and 4.3. In whole-cell mode, we recorded two outward currents, a delayed rectifier and an A-type current. CONCLUSIONS/SIGNIFICANCE We conclude that Kv2.1, and 4.3 are expressed in E15 SVZ neural progenitor cells, and we propose that they may be associated with the delayed-rectifier and the A-type currents, respectively, that we recorded. These results demonstrate the early expression of delayed rectifier and A-type K(+) currents and channels in embryonic neural progenitor cells prior to the differentiation of these cells.
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Affiliation(s)
- Dean O Smith
- Stem Cell Research Laboratory, University of Hawaii at Manoa, Manoa, Hawaii, USA.
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