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Gonzalez-Burgos G, Miyamae T, Nishihata Y, Krimer OL, Wade K, Fish KN, Arion D, Cai ZL, Xue M, Stauffer WR, Lewis DA. Synaptic alterations in pyramidal cells following genetic manipulation of neuronal excitability in monkey prefrontal cortex. J Neurophysiol 2025; 133:399-413. [PMID: 39740351 DOI: 10.1152/jn.00326.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Revised: 12/16/2024] [Accepted: 12/21/2024] [Indexed: 01/02/2025] Open
Abstract
The primate dorsolateral prefrontal cortex (DLPFC) displays unique in vivo activity patterns, but how in vivo activity regulates DLPFC pyramidal neuron (PN) properties remains unclear. We assessed the effects of in vivo Kir2.1 overexpression, a genetic silencing tool, on synapses in monkey DLPFC PNs. We show for the first time that recombinant ion channel expression successfully modifies the excitability of primate cortex neurons, producing effects on synaptic properties apparently different from those in the rodent cortex.
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Affiliation(s)
| | - Takeaki Miyamae
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Yosuke Nishihata
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Olga L Krimer
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Kirsten Wade
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Kenneth N Fish
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Dominique Arion
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Zhao-Lin Cai
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas, United States
| | - Mingshan Xue
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States
| | - William R Stauffer
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - David A Lewis
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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Ahlström S, Reiterä P, Jokela R, Olkkola KT, Kaunisto MA, Kalso E. Influence of Clinical and Genetic Factors on Propofol Dose Requirements: A Genome-wide Association Study. Anesthesiology 2024; 141:300-312. [PMID: 38700459 DOI: 10.1097/aln.0000000000005036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
BACKGROUND Propofol is a widely used intravenous hypnotic. Dosing is based mostly on weight, with great interindividual variation in consumption. Suggested factors affecting propofol requirements include age, sex, ethnicity, anxiety, alcohol consumption, smoking, and concomitant valproate use. Genetic factors have not been widely explored. METHODS This study considered 1,000 women undergoing breast cancer surgery under propofol and remifentanil anesthesia. Depth of anesthesia was monitored with State Entropy (GE Healthcare, Finland). Propofol requirements during surgery were recorded. DNA from blood was genotyped with a genome-wide array. A multivariable linear regression model was used to assess the relevance of clinical variables and select those to be used as covariates in a genome-wide association study. Imputed genotype data were used to explore selected loci further. In silico functional annotation was used to explore possible consequences of the discovered genetic variants. Additionally, previously reported genetic associations from candidate gene studies were tested. RESULTS Body mass index, smoking status, alcohol use, remifentanil dose (ln[mg · kg-1 · min-1]), and average State Entropy during surgery remained statistically significant in the multivariable model. Two loci reached genome-wide significance (P < 5 × 10-8). The most significant associations were for single-nucleotide polymorphisms rs997989 (30 kb from ROBO3), likely affecting expression of another nearby gene, FEZ1, and rs9518419, close to NALCN (sodium leak channel); rs10512538 near KCNJ2 encoding the Kir2.1 potassium channel showed suggestive association (P = 4.7 × 10-7). None of these single-nucleotide polymorphisms are coding variants but possibly affect the regulation of nearby genes. None of the single-nucleotide polymorphisms previously reported as affecting propofol pharmacokinetics or pharmacodynamics showed association in the data. CONCLUSIONS In this first genome-wide association study exploring propofol requirements, This study discovered novel genetic associations suggesting new biologically relevant pathways for propofol and general anesthesia. The roles of the gene products of ROBO3/FEZ1, NALCN, and KCNJ2 in propofol anesthesia warrant further studies. EDITOR’S PERSPECTIVE
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Affiliation(s)
- Sirkku Ahlström
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Helsinki and HUS Helsinki University Hospital, Helsinki, Finland
| | - Paula Reiterä
- Department of Public Health, University of Helsinki and HUS Helsinki University Hospital, Helsinki, Finland
| | - Ritva Jokela
- HUS Shared Group Services, University of Helsinki and HUS Helsinki University Hospital, Helsinki, Finland
| | - Klaus T Olkkola
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Helsinki and HUS Helsinki University Hospital, Helsinki, Finland; INDIVIDRUG Research Program, Faculty of Medicine, University of Helsinki, Finland
| | - Mari A Kaunisto
- Institute for Molecular Medicine Finland, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Eija Kalso
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Helsinki and HUS Helsinki University Hospital, Helsinki, Finland; Department of Pharmacology, Faculty of Medicine, University of Helsinki, Finland; SleepWell Research Program, Faculty of Medicine, University of Helsinki, Finland
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Tian T, Cai Y, Qin X, Wang J, Wang Y, Yang X. Forebrain E-I balance controlled in cognition through coordinated inhibition and inhibitory transcriptome mechanism. Front Cell Neurosci 2023; 17:1114037. [PMID: 36909282 PMCID: PMC10000298 DOI: 10.3389/fncel.2023.1114037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 01/31/2023] [Indexed: 02/26/2023] Open
Abstract
Introduction Forebrain neural networks are vital for cognitive functioning, and their excitatory-inhibitory (E-I) balance is governed by neural homeostasis. However, the homeostatic control strategies and transcriptomic mechanisms that maintain forebrain E-I balance and optimal cognition remain unclear. Methods We used patch-clamp and RNA sequencing to investigate the patterns of neural network homeostasis with suppressing forebrain excitatory neural activity and spatial training. Results We found that inhibitory transmission and receptor transcription were reduced in tamoxifen-inducible Kir2.1 conditional knock-in mice. In contrast, spatial training increased inhibitory synaptic connections and the transcription of inhibitory receptors. Discussion Our study provides significant evidence that inhibitory systems play a critical role in the homeostatic control of the E-I balance in the forebrain during cognitive training and E-I rebalance, and we have provided insights into multiple gene candidates for cognition-related homeostasis in the forebrain.
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Affiliation(s)
- Tian Tian
- Shenzhen Key Laboratory of Translational Research for Brain Diseases, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - You Cai
- Shenzhen Key Laboratory of Translational Research for Brain Diseases, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Department of Neurology, Shenzhen Institute of Translational Medicine, Shenzhen Second People’s Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, China
| | - Xin Qin
- Department of Medicine, Djavad Mowafaghian Centre for Brain Health, The University of British Columbia, Vancouver, BC, Canada
| | - Jiangang Wang
- Henan International Joint Laboratory of Non-Invasive Neuromodulation, Department of Physiology and Pathophysiology, Xinxiang Medical University, Xinxiang, China
| | - Yali Wang
- Henan International Joint Laboratory of Non-Invasive Neuromodulation, Department of Physiology and Pathophysiology, Xinxiang Medical University, Xinxiang, China
| | - Xin Yang
- Shenzhen Key Laboratory of Translational Research for Brain Diseases, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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Single-Cell Labeling Strategies to Dissect Neuronal Structures and Local Functions. BIOLOGY 2023; 12:biology12020321. [PMID: 36829594 PMCID: PMC9953318 DOI: 10.3390/biology12020321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/09/2023] [Accepted: 02/14/2023] [Indexed: 02/19/2023]
Abstract
The brain network consists of ten billion neurons and is the most complex structure in the universe. Understanding the structure of complex brain networks and neuronal functions is one of the main goals of modern neuroscience. Since the seminal invention of Golgi staining, single-cell labeling methods have been among the most potent approaches for dissecting neuronal structures and neural circuits. Furthermore, the development of sparse single-cell transgenic methods has enabled single-cell gene knockout studies to examine the local functions of various genes in neural circuits and synapses. Here, we review non-transgenic single-cell labeling methods and recent advances in transgenic strategies for sparse single neuronal labeling. These methods and strategies will fundamentally contribute to the understanding of brain structure and function.
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Viral vector-mediated expressions of venom peptides as novel gene therapy for anxiety and depression. Med Hypotheses 2022. [DOI: 10.1016/j.mehy.2022.110910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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Therapeutic potential of viral vectors that express venom peptides for neurological diseases. Med Hypotheses 2022. [DOI: 10.1016/j.mehy.2022.110809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Ubina T, Vahedi-Hunter T, Agnew-Svoboda W, Wong W, Gupta A, Santhakumar V, Riccomagno MM. ExBoX - a simple Boolean exclusion strategy to drive expression in neurons. J Cell Sci 2021; 134:272538. [PMID: 34515305 PMCID: PMC8572001 DOI: 10.1242/jcs.257212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 09/03/2021] [Indexed: 11/20/2022] Open
Abstract
The advent of modern single-cell biology has revealed the striking molecular diversity of cell populations once thought to be more homogeneous. This newly appreciated complexity has made intersectional genetic approaches essential to understanding and probing cellular heterogeneity at the functional level. Here, we build on previous knowledge to develop a simple adeno-associated virus (AAV)-based approach to define specific subpopulations of cells by Boolean exclusion logic (AND NOT). This expression by Boolean exclusion (ExBoX) system encodes for a gene of interest that is turned on by a particular recombinase (Cre or FlpO) and turned off by another. ExBoX allows for the specific transcription of a gene of interest in cells expressing only the activating recombinase, but not in cells expressing both. We show the ability of the ExBoX system to tightly regulate expression of fluorescent reporters in vitro and in vivo, and further demonstrate the adaptability of the system by achieving expression of a variety of virally delivered coding sequences in the mouse brain. This simple strategy will expand the molecular toolkit available for cell- and time-specific gene expression in a variety of systems. Summary: The generation of a novel AAV-based intersectional approach to define and target specific subpopulations of cells in time and space via a Expression by Boolean Exclusion (ExBoX) system.
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Affiliation(s)
- Teresa Ubina
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Tyler Vahedi-Hunter
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Will Agnew-Svoboda
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Wenny Wong
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Akshay Gupta
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Vijayalakshmi Santhakumar
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
| | - Martin M Riccomagno
- Neuroscience Graduate Program, Department of Molecular, Cell & Systems Biology, University of California, Riverside, CA 92521, USA
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Hu B, Boyle CA, Lei S. Roles of PLCβ, PIP 2 , and GIRK channels in arginine vasopressin-elicited excitation of CA1 pyramidal neurons. J Cell Physiol 2021; 237:660-674. [PMID: 34287874 DOI: 10.1002/jcp.30535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/29/2021] [Accepted: 07/09/2021] [Indexed: 12/15/2022]
Abstract
Arginine vasopressin (AVP) is a hormone exerting vasoconstrictive and antidiuretic action in the periphery and serves as a neuromodulator in the brain. Although the hippocampus receives vasopressinergic innervation and AVP has been shown to facilitate the excitability of CA1 pyramidal neurons, the involved ionic and signaling mechanisms have not been determined. Here we found that AVP excited CA1 pyramidal neurons by activation of V1a receptors. Functions of G proteins and phospholipase Cβ (PLCβ) were required for AVP-elicited excitation of CA1 pyramidal neurons, whereas intracellular Ca2+ release and protein kinase C were unnecessary. PLCβ-mediated depletion of phosphatidylinositol 4,5-bisphosphate (PIP2 ) was required for AVP-elicited excitation of CA1 pyramidal neurons. AVP augmented the input resistance and increased the time constants of CA1 pyramidal neurons. AVP induced an inward current in K+ -containing intracellular solution, whereas no inward currents were observed with Cs+ -containing intracellular solution. AVP-sensitive currents showed inward rectification with a reversal potential close to the K+ reversal potential, suggesting the involvement of inwardly rectifying K+ channels. AVP-induced currents were sensitive to the micromolar concentration of Ba2+ and tertiapin-Q, whereas application of ML 133, a selective Kir2 channel blocker had no effects, suggesting that AVP excited CA1 pyramidal neurons by depressing G protein-gated inwardly rectifying K+ channels. Activation of V1a receptors in the CA1 region facilitated glutamatergic transmission onto subicular pyramidal neurons, suggesting that AVP modulates network activity in the brain. Our results may provide one of the cellular and molecular mechanisms to explain the in vivo physiological functions of AVP.
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Affiliation(s)
- Binqi Hu
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Cody A Boyle
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Saobo Lei
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
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Pore-forming spider venom peptides show cytotoxicity to hyperpolarized cancer cells expressing K+ channels: A lentiviral vector approach. PLoS One 2019; 14:e0215391. [PMID: 30978253 PMCID: PMC6461346 DOI: 10.1371/journal.pone.0215391] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 04/01/2019] [Indexed: 12/03/2022] Open
Abstract
Recent studies demonstrated the upregulation of K+ channels in cancer cells. We have previously found that a pore-forming peptide LaFr26, purified from the venom of the Lachesana sp spider, was selectively incorporated into K+ channel expressing hyperpolarized cells. Therefore, it is expected that this peptide would have selective cytotoxicity to hyperpolarized cancer cells. Here we have tested whether LaFr26 and its related peptide, oxyopinin-2b, are selectively cytotoxic to K+ channel expressing cancer cells. These peptides were cytotoxic to the cells, of which resting membrane potential was hyperpolarized. The vulnerabilities of K+ channel-expressing cell lines correlated with their resting membrane potential. They were cytotoxic to lung cancer cell lines LX22 and BEN, which endogenously expressed K+ current. Contrastingly, these peptides were ineffective to glioblastoma cell lines, U87 and T98G, of which membrane potentials were depolarized. Peptides have a drawback, i.e. poor drug-delivery, that hinders their potential use as medicine. To overcome this drawback, we prepared lentiviral vectors that can express these pore-forming peptides and tested the cytotoxicity to K+ channel expressing cells. The transduction with these lentiviral vectors showed autotoxic activity to the channel expressing cells. Our study provides the basis for a new oncolytic viral therapy.
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Abstract
Hypertension is a prevalent and major health problem, involving a complex integration of different organ systems, including the central nervous system (CNS). The CNS and the hypothalamus in particular are intricately involved in the pathogenesis of hypertension. In fact, evidence supports altered hypothalamic neuronal activity as a major factor contributing to increased sympathetic drive and increased blood pressure. Several mechanisms have been proposed to contribute to hypothalamic-driven sympathetic activity, including altered ion channel function. Ion channels are critical regulators of neuronal excitability and synaptic function in the brain and, thus, important for blood pressure homeostasis regulation. These include sodium channels, voltage-gated calcium channels, and potassium channels being some of them already identified in hypothalamic neurons. This brief review summarizes the hypothalamic ion channels that may be involved in hypertension, highlighting recent findings that suggest that hypothalamic ion channel modulation can affect the central control of blood pressure and, therefore, suggesting future development of interventional strategies designed to treat hypertension.
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Affiliation(s)
- Vera Geraldes
- Instituto de Fisiologia, Universidade de Lisboa, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028, Lisbon, Portugal
| | - Sérgio Laranjo
- Instituto de Fisiologia, Universidade de Lisboa, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028, Lisbon, Portugal
| | - Isabel Rocha
- Instituto de Fisiologia, Universidade de Lisboa, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028, Lisbon, Portugal. .,Centro Cardiovascular da Universidade de Lisboa, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028, Lisbon, Portugal.
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Auffenberg E, Jurik A, Mattusch C, Stoffel R, Genewsky A, Namendorf C, Schmid RM, Rammes G, Biel M, Uhr M, Moosmang S, Michalakis S, Wotjak CT, Thoeringer CK. Remote and reversible inhibition of neurons and circuits by small molecule induced potassium channel stabilization. Sci Rep 2016; 6:19293. [PMID: 26757616 PMCID: PMC4725838 DOI: 10.1038/srep19293] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 12/09/2015] [Indexed: 01/12/2023] Open
Abstract
Manipulating the function of neurons and circuits that translate electrical and chemical signals into behavior represents a major challenges in neuroscience. In addition to optogenetic methods using light-activatable channels, pharmacogenetic methods with ligand induced modulation of cell signaling and excitability have been developed. However, they are largely based on ectopic expression of exogenous or chimera proteins. Now, we describe the remote and reversible expression of a Kir2.1 type potassium channel using the chemogenetic technique of small molecule induced protein stabilization. Based on shield1-mediated shedding of a destabilizing domain fused to a protein of interest and inhibition of protein degradation, this principle has been adopted for biomedicine, but not in neuroscience so far. Here, we apply this chemogenetic approach in brain research for the first time in order to control a potassium channel in a remote and reversible manner. We could show that shield1-mediated ectopic Kir2.1 stabilization induces neuronal silencing in vitro and in vivo in the mouse brain. We also validated this novel pharmacogenetic method in different neurobehavioral paradigms.The DD-Kir2.1 may complement the existing portfolio of pharmaco- and optogenetic techniques for specific neuron manipulation, but it may also provide an example for future applications of this principle in neuroscience research.
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Affiliation(s)
- Eva Auffenberg
- Department of Internal Medicine II, Klinikum rechts der Isar, Technical University of Munich, Germany
| | - Angela Jurik
- Department of Internal Medicine II, Klinikum rechts der Isar, Technical University of Munich, Germany
| | - Corinna Mattusch
- Institute of Anesthesiology, Technical University of Munich, Germany
| | - Rainer Stoffel
- Max Planck Institute of Psychiatry, Department of Stress Physiology and Neurogenetics, Munich, Germany
| | - Andreas Genewsky
- Max Planck Institute of Psychiatry, Department of Stress Physiology and Neurogenetics, Munich, Germany
| | - Christian Namendorf
- Max Planck Institute of Psychiatry, Department of Stress Physiology and Neurogenetics, Munich, Germany
| | - Roland M Schmid
- Department of Internal Medicine II, Klinikum rechts der Isar, Technical University of Munich, Germany
| | - Gerhard Rammes
- Institute of Anesthesiology, Technical University of Munich, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich (CIPSM) and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-University of Munich, Germany
| | - Manfred Uhr
- Max Planck Institute of Psychiatry, Department of Stress Physiology and Neurogenetics, Munich, Germany
| | - Sven Moosmang
- Institute of Pharmacology, Technical University of Munich, Germany
| | - Stylianos Michalakis
- Center for Integrated Protein Science Munich (CIPSM) and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-University of Munich, Germany
| | - Carsten T Wotjak
- Max Planck Institute of Psychiatry, Department of Stress Physiology and Neurogenetics, Munich, Germany
| | - Christoph K Thoeringer
- Department of Internal Medicine II, Klinikum rechts der Isar, Technical University of Munich, Germany
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Increase in the titer of lentiviral vectors expressing potassium channels by current blockade during viral vector production. BMC Neurosci 2015; 16:30. [PMID: 25940378 PMCID: PMC4425897 DOI: 10.1186/s12868-015-0159-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 04/01/2015] [Indexed: 12/02/2022] Open
Abstract
Background High titers of lentiviral vectors are required for the efficient transduction of a gene of interest. During preparation of lentiviral the vectors, the protein of interest is inevitably expressed in the viral vector-producing cells. This expression may affect the production of the lentiviral vector. Methods We prepared lentiviral vectors expressing inwardly rectifying potassium channel (Lv-Kir2.1), its dominant-negative form (Lv-Kir-DN), and other K+ channels, using the ubiquitously active β-actin and neuron-specific synapsin I promoters. Results The titer of Lv-Kir-DN was higher than that of Lv-Kir2.1, suggesting a negative effect of induced K+ currents on viral titer. We then blocked Kir2.1 currents with the selective blocker Ba2+ during Lv-Kir2.1 production, and obtained about a 5-fold increase in the titer. Higher extracellular K+ concentrations increased the titer of Lv-Kir2.1 about 9-fold. With a synapsin I promoter Ba2+ increased the titer because of the moderate expression of Kir2.1 channel. Channel blockade also increased the titers of the lentivirus expressing Kv1.4 and TREK channels, but not HERG. The increase in titer correlated with the K+ currents generated by the channels expressed. Conclusion In the production of lentivirus expressing K+ channels, titers are increased by blocking K+ currents in the virus-producing cells. This identifies a crucial issue in the production of viruses expressing membrane channels, and should facilitate basic and gene therapeutic research on channelopathies.
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Okada M, Corzo G, Romero-Perez GA, Coronas F, Matsuda H, Possani LD. A pore forming peptide from spider Lachesana sp. venom induced neuronal depolarization and pain. Biochim Biophys Acta Gen Subj 2015; 1850:657-66. [DOI: 10.1016/j.bbagen.2014.11.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 11/12/2014] [Accepted: 11/28/2014] [Indexed: 10/24/2022]
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Geraldes V, Goncalves-Rosa N, Liu B, Paton JF, Rocha I. Essential role of RVL medullary neuronal activity in the long term maintenance of hypertension in conscious SHR. Auton Neurosci 2014; 186:22-31. [DOI: 10.1016/j.autneu.2014.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 08/14/2014] [Accepted: 09/05/2014] [Indexed: 02/07/2023]
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Geraldes V, Gonçalves-Rosa N, Liu B, Paton JFR, Rocha I. Chronic depression of hypothalamic paraventricular neuronal activity produces sustained hypotension in hypertensive rats. Exp Physiol 2013; 99:89-100. [PMID: 24142454 DOI: 10.1113/expphysiol.2013.074823] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Changes in the sympathetic nervous system are responsible for the initiation, development and maintenance of hypertension. An important central sympathoexcitatory region is the paraventricular nucleus (PVN) of the hypothalamus, which may become more active in hypertensive conditions, as shown in acute studies previously. Our objective was to depress PVN neuronal activity chronically by the overexpression of an inwardly rectifying potassium channel (hKir2.1), while evaluating the consequences on blood pressure (BP) and its reflex regulation. In spontaneously hypertensive rats (SHRs) and Wistar rats (WKY) lentiviral vectors (LVV-hKir2.1; LV-TREtight-Kir-cIRES-GFP5 4 × 10(9) IU and LV-Syn-Eff-G4BS-Syn-Tetoff 6.2 × 10(9) IU in a ratio 1:4) were stereotaxically microinjected bilaterally into the PVN. Sham-treated SHRs and WKY received bilateral PVN microinjections of LVV-eGFP (LV-Syn-Eff-G4BS-Syn-Tetoff 6.2 × 10(9) IU and LV-TREtight-GFP 5.7 × 10(9) IU in a ratio 1:4). Blood pressure was monitored continuously by radio-telemetry and evaluated over 75 days. Baroreflex gain was evaluated using phenylephrine (25 μg ml(-1), i.v.), whereas lobeline (25 μg ml(-1), i.v.) was used to stimulate peripheral chemoreceptors. In SHRs but not normotensive WKY rats, LVV-hKir2.1 expression in the PVN produced time-dependent and significant decreases in systolic (from 158 ± 3 to 132 ± 6 mmHg; P < 0.05) and diastolic BP (from 135 ± 4 to 113 ± 5 mmHg; P < 0.05). The systolic BP low-frequency band was reduced (from 0.79 ± 0.13 to 0.42 ± 0.09 mmHg(2); P < 0.05), suggesting reduced sympathetic vasomotor tone. Baroreflex gain was increased and peripheral chemoreflex depressed after PVN microinjection of LVV-hKir2.1. We conclude that the PVN plays a major role in long-term control of BP and sympathetic nervous system activity in SHRs. This is associated with reductions in both peripheral chemosensitivity and respiratory-induced sympathetic modulation and an improvement in baroreflex sensitivity. Our results support the PVN as a powerful site to control BP in neurogenic hypertension.
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Affiliation(s)
- Vera Geraldes
- I. Rocha: Instituto de Fisiologia, Faculdade de Medicina de Lisboa, Av Prof Egas Moniz, 1649-028 Lisbon, Portugal.
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The degradation of the inwardly rectifying potassium channel, Kir2.1, depends on the expression level: examination with fluorescent proteins. Brain Res 2013; 1528:8-19. [PMID: 23850646 DOI: 10.1016/j.brainres.2013.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 07/01/2013] [Accepted: 07/05/2013] [Indexed: 01/24/2023]
Abstract
The expression of ion channels is regulated by their synthesis as well as degradation, and some ion channels are degraded in an expression level-dependent way. Recently, new techniques of fluorescent proteins have been developed and seem to be useful to study protein degradation. To examine the regulation of the degradation of strongly inwardly rectifying potassium channel (Kir2.1) and the usefulness of the fluorescent proteins, we constructed Kir2.1 fusion proteins with SNAP tag and fluorescent timer (FT). The SNAP tag, which covalently binds to a specific membrane-permeable fluorescent dye, enables a pulse-chase experiment with fluorescence. When the SNAP-Kir2.1 proteins were expressed in 293T cells by low and high expression plasmids, the half-life of the fusion protein expressed by a high-expression plasmid was shorter (18.2±1.9 h) than that expressed by a low-expression plasmid (35.1+2.3h). The addition of Ba(2+), a selective blocker of Kir2.1, slowed the degradation, suggesting a current-dependency of degradation. Consistently, patch-clamp recording showed that cultivation in the presence of Ba(2+) increased the whole cell conductance of SNAP-Kir2.1. Since the fluorescence of FT changes gradually changes from green to red, the green/red ratio should allow us to monitor the changes in the degradation rate of FT-Kir2.1. Using this method, we confirmed the slower degradation by Ba(2+). The results suggest a homeostatic regulation of the degradation of Kir2.1 in the 293T cells, and the usefulness of fluorescence-based methods for examining the degradation of ion channels.
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Okada M, Matsuda H, Okimura Y. Lentiviral and Moloney retroviral expression of green fluorescent protein in somatotrophs in vivo. PLoS One 2013; 8:e54437. [PMID: 23342159 PMCID: PMC3546981 DOI: 10.1371/journal.pone.0054437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 12/13/2012] [Indexed: 11/19/2022] Open
Abstract
Previous studies have shown that the locus control region (LCR) and the promoter of the growth hormone (GH) gene can control the expression of GH. Therefore, lenti- and retro-viral vectors with these elements might be useful to monitor the activation of the GH gene and the development of newborn somatotrophs. To test this, we first constructed a lentiviral vector, which expresses green fluorescent protein (GFP) under the control of these elements, and injected them into rat pituitaries in situ and in vivo. The lentiviral vector expressed GFP specifically in the anterior lobe, and nearly all GFP-positive cells were anti-GH immunoreactive. The GFP expression was upregulated by the administration of growth hormone releasing hormone and an IGF-1 receptor blocker. Furthermore, the social isolation stress, which was shown to decrease the GH secretion, decreased the GFP expression. Second, we injected the retroviral vector into neonatal rat pituitaries in vivo. At 30 days postinjection (DPI), almost all GFP-positive cells were anti-GH positive and anti-prolactin negative as the lentiviral expression. However, GFP was transiently expressed by developing lactotrophs at 8 and 16 DPI, suggesting that our vector lacks an element(s) which suppresses the expression. Meanwhile, the retrovirally labeled cells tended to cluster with the cells of same type. An analysis of cell numbers in each cluster revealed some features of cell proliferation. These viral vectors are shown to be useful tools to monitor the activation of the GH gene and the development of somatotrophs.
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Affiliation(s)
- Masayoshi Okada
- Department of Physiology, Kansai Medical University, Moriguchi City, Osaka, Japan.
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Zschüntzsch J, Schütze S, Hülsmann S, Dibaj P, Neusch C. Heterologous expression of a glial Kir channel (KCNJ10) in a neuroblastoma spinal cord (NSC-34) cell line. Physiol Res 2012; 62:95-105. [PMID: 23173681 DOI: 10.33549/physiolres.932264] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Heterologous expression of Kir channels offers a tool to modulate excitability of neurons which provide insight into Kir channel functions in general. Inwardly-rectifying K+ channels (Kir channels) are potential candidate proteins to hyperpolarize neuronal cell membranes. However, heterologous expression of inwardly-rectifying K+ channels has previously proven to be difficult. This was mainly due to a high toxicity of the respective Kir channel expression. We investigated the putative role of a predominantly glial-expressed, weakly rectifying Kir channel (Kir4.1 channel subunit; KCNJ10) in modulating electrophysiological properties of a motoneuron-like cell culture (NSC-34). Transfection procedures using an EGFP-tagged Kir4.1 protein in this study proved to have no toxic effects on NSC-34 cells. Using whole cell-voltage clamp, a substantial increase of inward rectifying K+ currents as well as hyperpolarization of the cell membrane was observed in Kir4.1-transfected cells. Na+ inward currents, observed in NSC-34 controls, were absent in Kir4.1/EGFP motoneuronal cells. The Kir4.1-transfection did not influence the NaV1.6 sodium channel expression. This study demonstrates the general feasibility of a heterologous expression of a weakly inward-rectifying K+ channel (Kir4.1 subunit) and shows that in vitro overexpression of Kir4.1 shifts electrophysiological properties of neuronal cells to a more glial-like phenotype and may therefore be a candidate tool to dampen excitability of neurons in experimental paradigms.
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Affiliation(s)
- J Zschüntzsch
- Department of Neurology, Georg-August-University, Göttingen, Germany
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Crawford DC, Moulder KL, Gereau RW, Story GM, Mennerick S. Comparative effects of heterologous TRPV1 and TRPM8 expression in rat hippocampal neurons. PLoS One 2009; 4:e8166. [PMID: 19997638 PMCID: PMC2780724 DOI: 10.1371/journal.pone.0008166] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 11/09/2009] [Indexed: 11/19/2022] Open
Abstract
Heterologous channel expression can be used to control activity in select neuronal populations, thus expanding the tools available to modern neuroscience. However, the secondary effects of exogenous channel expression are often left unexplored. We expressed two transient receptor potential (TRP) channel family members, TRPV1 and TRPM8, in cultured hippocampal neurons. We compared functional expression levels and secondary effects of channel expression and activation on neuronal survival and signaling. We found that activation of both channels with appropriate agonist caused large depolarizing currents in voltage-clamped hippocampal neurons, exceeding the amplitude responses to a calibrating 30 mM KCl stimulation. Both TRPV1 and TRPM8 currents were reduced but not eliminated by 4 hr incubation in saturating agonist concentration. In the case of TRPV1, but not TRPM8, prolonged agonist exposure caused strong calcium-dependent toxicity. In addition, TRPV1 expression depressed synaptic transmission dramatically without overt signs of toxicity, possibly due to low-level TRPV1 activation in the absence of exogenous agonist application. Despite evidence of expression at presynaptic sites, in addition to somatodendritic sites, TRPM8 expression alone exhibited no effects on synaptic transmission. Therefore, by a number of criteria, TRPM8 proved the superior choice for control over neuronal membrane potential. This study also highlights the need to explore potential secondary effects of long-term expression and activation of heterologously introduced channels.
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Affiliation(s)
- Devon C. Crawford
- Graduate Program in Neurosciences, Washington University, St. Louis, Missouri, United States of America
- Department of Psychiatry, Washington University, St. Louis, Missouri, United States of America
| | - Krista L. Moulder
- Department of Psychiatry, Washington University, St. Louis, Missouri, United States of America
| | - Robert W. Gereau
- Department of Anesthesiology, Washington University, St. Louis, Missouri, United States of America
- Department of Anatomy and Neurobiology, Washington University, St. Louis, Missouri, United States of America
| | - Gina M. Story
- Department of Anesthesiology, Washington University, St. Louis, Missouri, United States of America
- Department of Anatomy and Neurobiology, Washington University, St. Louis, Missouri, United States of America
| | - Steven Mennerick
- Department of Psychiatry, Washington University, St. Louis, Missouri, United States of America
- Department of Anatomy and Neurobiology, Washington University, St. Louis, Missouri, United States of America
- * E-mail:
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