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Varlamova EG, Borisova EV, Evstratova YA, Newman AG, Kuldaeva VP, Gavrish MS, Kondakova EV, Tarabykin VS, Babaev AA, Turovsky EA. Socrates: A Novel N-Ethyl-N-nitrosourea-Induced Mouse Mutant with Audiogenic Epilepsy. Int J Mol Sci 2023; 24:17104. [PMID: 38069426 PMCID: PMC10707124 DOI: 10.3390/ijms242317104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/23/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
Epilepsy is one of the common neurological diseases that affects not only adults but also infants and children. Because epilepsy has been studied for a long time, there are several pharmacologically effective anticonvulsants, which, however, are not suitable as therapy for all patients. The genesis of epilepsy has been extensively investigated in terms of its occurrence after injury and as a concomitant disease with various brain diseases, such as tumors, ischemic events, etc. However, in the last decades, there are multiple reports that both genetic and epigenetic factors play an important role in epileptogenesis. Therefore, there is a need for further identification of genes and loci that can be associated with higher susceptibility to epileptic seizures. Use of mouse knockout models of epileptogenesis is very informative, but it has its limitations. One of them is due to the fact that complete deletion of a gene is not, in many cases, similar to human epilepsy-associated syndromes. Another approach to generating mouse models of epilepsy is N-Ethyl-N-nitrosourea (ENU)-directed mutagenesis. Recently, using this approach, we generated a novel mouse strain, soc (socrates, formerly s8-3), with epileptiform activity. Using molecular biology methods, calcium neuroimaging, and immunocytochemistry, we were able to characterize the strain. Neurons isolated from soc mutant brains retain the ability to differentiate in vitro and form a network. However, soc mutant neurons are characterized by increased spontaneous excitation activity. They also demonstrate a high degree of Ca2+ activity compared to WT neurons. Additionally, they show increased expression of NMDA receptors, decreased expression of the Ca2+-conducting GluA2 subunit of AMPA receptors, suppressed expression of phosphoinositol 3-kinase, and BK channels of the cytoplasmic membrane involved in protection against epileptogenesis. During embryonic and postnatal development, the expression of several genes encoding ion channels is downregulated in vivo, as well. Our data indicate that soc mutation causes a disruption of the excitation-inhibition balance in the brain, and it can serve as a mouse model of epilepsy.
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Affiliation(s)
- Elena G. Varlamova
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, 142290 Pushchino, Russia;
| | - Ekaterina V. Borisova
- Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; (E.V.B.); (A.G.N.)
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
| | - Yuliya A. Evstratova
- Federal State Budgetary Educational Institution of Higher Education “MIREA—Russian Technological University”, 78, Vernadskogo Ave., 119454 Moscow, Russia;
| | - Andrew G. Newman
- Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; (E.V.B.); (A.G.N.)
| | - Vera P. Kuldaeva
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Russian Academy of Sciences, 10 Nab. Ushaiki, 634050 Tomsk, Russia
| | - Maria S. Gavrish
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
| | - Elena V. Kondakova
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Russian Academy of Sciences, 10 Nab. Ushaiki, 634050 Tomsk, Russia
| | - Victor S. Tarabykin
- Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; (E.V.B.); (A.G.N.)
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Russian Academy of Sciences, 10 Nab. Ushaiki, 634050 Tomsk, Russia
| | - Alexey A. Babaev
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
| | - Egor A. Turovsky
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, 142290 Pushchino, Russia;
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., 603022 Nizhny Novgorod, Russia; (V.P.K.); (M.S.G.); (E.V.K.); (A.A.B.)
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Varlamova EG, Plotnikov EY, Turovsky EA. Neuronal Calcium Sensor-1 Protects Cortical Neurons from Hyperexcitation and Ca 2+ Overload during Ischemia by Protecting the Population of GABAergic Neurons. Int J Mol Sci 2022; 23:ijms232415675. [PMID: 36555318 PMCID: PMC9778989 DOI: 10.3390/ijms232415675] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
A defection of blood circulation in the brain leads to ischemia, damage, and the death of nerve cells. It is known that individual populations of GABAergic neurons are the least resistant to the damaging factors of ischemia and therefore they die first of all, which leads to impaired inhibition in neuronal networks. To date, the neuroprotective properties of a number of calcium-binding proteins (calbindin, calretinin, and parvalbumin), which are markers of GABAergic neurons, are known. Neuronal calcium sensor-1 (NCS-1) is a signaling protein that is expressed in all types of neurons and is involved in the regulation of neurotransmission. The role of NCS-1 in the protection of neurons and especially their individual populations from ischemia and hyperexcitation has not been practically studied. In this work, using the methods of fluorescence microscopy, vitality tests, immunocytochemistry, and PCR analysis, the molecular mechanisms of the protective action of NCS-1 in ischemia/reoxygenation and hyperammonemia were established. Since NCS-1 is most expressed in GABAergic neurons, the knockdown of this protein with siRNA led to the most pronounced consequences in GABAergic neurons. The knockdown of NCS-1 (NCS-1-KD) suppressed the basic expression of protective proteins without significantly reducing cell viability. However, ischemia-like conditions (oxygen-glucose deprivation, OGD) and subsequent 24-h reoxygenation led to a more massive activation of apoptosis and necrosis in neurons with NCS-1-KD, compared to control cells. The mass death of NCS-1-KD cells during OGD and hyperammonemia has been associated with the induction of a more pronounced network hyperexcitation symptom, especially in the population of GABAergic neurons, leading to a global increase in cytosolic calcium ([Ca2+]i). The symptom of hyperexcitation of neurons with NCS-1-KD correlated with a decrease in the level of expression of the calcium-binding protein-parvalbumin. This was accompanied by an increase in the expression of excitatory ionotropic glutamate receptors, N-methyl-D-aspartate and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (NMDAR and AMPAR) against the background of suppression of the expression of glutamate decarboxylase (synthesis of γ-aminobutyric acid).
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Affiliation(s)
- Elena G. Varlamova
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, 142290 Pushchino, Russia
- Correspondence: (E.G.V.); (E.A.T.)
| | - Egor Y. Plotnikov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, 117997 Moscow, Russia
| | - Egor A. Turovsky
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”, 142290 Pushchino, Russia
- Correspondence: (E.G.V.); (E.A.T.)
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Cytoprotective Properties of a New Nanocomplex of Selenium with Taxifolin in the Cells of the Cerebral Cortex Exposed to Ischemia/Reoxygenation. Pharmaceutics 2022; 14:pharmaceutics14112477. [PMID: 36432668 PMCID: PMC9697510 DOI: 10.3390/pharmaceutics14112477] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/07/2022] [Accepted: 11/14/2022] [Indexed: 11/18/2022] Open
Abstract
The neuroprotective effect of the natural antioxidant taxifolin (TAX) is well known for ischemic pathologies. However, the limitations of taxifolin application are described-poor solubility, low ability to penetrate the blood-brain barrier, and side effects from high doses for stroke therapy. We proposed the problem of targeted delivery of taxifolin and achievement effective concentrations could be solved by developing a nanocomplex of selenium nanoparticles (SeNPs) with taxifolin (Se-TAX). In this study, we developed a selenium-taxifolin nanocomplex based on selenium nanoparticles with a 100 nm size. It was shown that TAX, SeNPs, and Se-TAX were all able to suppress the production of ROS in neurons and astrocytes under exposure to exogenous H2O2 and ischemia-like conditions. However, the Se-TAX nanocomplex appeared to be the most effective, displaying a lower working concentration range and negligible pro-oxidant effect compared with pure SeNPs. The mechanism of Se-TAX beneficial effects involved the activation of some antioxidant enzymes and the suppression of ROS-generating systems during OGD/reoxygenation, while TAX and "naked" SeNPs were less effective in regulating the cellular redox status. Naked SeNPs inhibited a global increase in Ca2+ ions in cytosol, but not OGD-induced hyperexcitation of the neuroglial network, while Se-TAX suppressed both [Ca2+]i rise and hyperexcitation. The effect of TAX at similar doses appeared exclusively in inhibiting OGD-induced hyperexcitation. Analysis of necrosis and apoptosis after OGD/reoxygenation revealed the highest efficiency of the Se-TAX nanocomplex as well. Se-TAX suppressed the expression of proinflammatory and proapoptotic proteins with simultaneous activation of protective genes. We conclude that the Se-TAX nanocomplex combines the antioxidative features taxifolin and the antiapoptotic effect of nanoselenium, involving the regulation of Ca2+ dynamics.
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Size-Dependent Cytoprotective Effects of Selenium Nanoparticles during Oxygen-Glucose Deprivation in Brain Cortical Cells. Int J Mol Sci 2022; 23:ijms23137464. [PMID: 35806466 PMCID: PMC9267189 DOI: 10.3390/ijms23137464] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/02/2022] [Accepted: 07/04/2022] [Indexed: 02/04/2023] Open
Abstract
It is known that selenium nanoparticles (SeNPs) obtained on their basis have a pleiotropic effect, inducing the process of apoptosis in tumor cells, on the one hand, and protecting healthy tissue cells from death under stress, on the other hand. It has been established that SeNPs protect brain cells from ischemia/reoxygenation through activation of the Ca2+ signaling system of astrocytes and reactive astrogliosis. At the same time, for a number of particles, the limitations of their use, associated with their size, are shown. The use of nanoparticles with a diameter of less than 10 nm leads to their short life-time in the bloodstream and rapid removal by the liver. Nanoparticles larger than 200 nm activate the complement system and are also quickly removed from the blood. The effects of different-sized SeNPs on brain cells have hardly been studied. Using the laser ablation method, we obtained SeNPs of various diameters: 50 nm, 100 nm, and 400 nm. Using fluorescence microscopy, vitality tests, PCR analysis, and immunocytochemistry, it was shown that all three types of the different-sized SeNPs have a cytoprotective effect on brain cortex cells under conditions of oxygen-glucose deprivation (OGD) and reoxygenation (R), suppressing the processes of necrotic death and inhibiting different efficiency processes of apoptosis. All of the studied SeNPs activate the Ca2+ signaling system of astrocytes, while simultaneously inducing different types of Ca2+ signals. SeNPs sized at 50 nm- induce Ca2+ responses of astrocytes in the form of a gradual irreversible increase in the concentration of cytosolic Ca2+ ([Ca2+]i), 100 nm-sized SeNPs induce stable Ca2+ oscillations without increasing the base level of [Ca2+]i, and 400 nm-sized SeNPs cause mixed patterns of Ca2+ signals. Such differences in the level of astrocyte Ca2+ signaling can explain the different cytoprotective efficacy of SeNPs, which is expressed in the expression of protective proteins and the activation of reactive astrogliosis. In terms of the cytoprotective efficiency under OGD/R conditions, different-sized SeNPs can be arranged in descending order: 100 nm-sized > 400 nm-sized > 50 nm-sized.
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Varlamova EG, Turovsky EA, Babenko VA, Plotnikov EY. The Mechanisms Underlying the Protective Action of Selenium Nanoparticles against Ischemia/Reoxygenation Are Mediated by the Activation of the Ca 2+ Signaling System of Astrocytes and Reactive Astrogliosis. Int J Mol Sci 2021; 22:ijms222312825. [PMID: 34884629 PMCID: PMC8657910 DOI: 10.3390/ijms222312825] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 12/19/2022] Open
Abstract
In recent years, much attention has been paid to the study of the therapeutic effect of the microelement selenium, its compounds, especially selenium nanoparticles, with a large number of works devoted to their anticancer effects. Studies proving the neuroprotective properties of selenium nanoparticles in various neurodegenerative diseases began to appear only in the last 5 years. Nevertheless, the mechanisms of the neuroprotective action of selenium nanoparticles under conditions of ischemia and reoxygenation remain unexplored, especially for intracellular Ca2+ signaling and neuroglial interactions. This work is devoted to the study of the cytoprotective mechanisms of selenium nanoparticles in the neuroglial networks of the cerebral cortex under conditions of ischemia/reoxygenation. It was shown for the first time that selenium nanoparticles dose-dependently induce the generation of Ca2+ signals selectively in astrocytes obtained from different parts of the brain. The generation of these Ca2+ signals by astrocytes occurs through the release of Ca2+ ions from the endoplasmic reticulum through the IP3 receptor upon activation of the phosphoinositide signaling pathway. An increase in the concentration of cytosolic Ca2+ in astrocytes leads to the opening of connexin Cx43 hemichannels and the release of ATP and lactate into the extracellular medium, which trigger paracrine activation of the astrocytic network through purinergic receptors. Incubation of cerebral cortex cells with selenium nanoparticles suppresses ischemia-induced increase in cytosolic Ca2+ and necrotic cell death. Activation of A2 reactive astrocytes exclusively after ischemia/reoxygenation, a decrease in the expression level of a number of proapoptotic and proinflammatory genes, an increase in lactate release by astrocytes, and suppression of the hyperexcitation of neuronal networks formed the basis of the cytoprotective effect of selenium nanoparticles in our studies.
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Affiliation(s)
- Elena G. Varlamova
- Federal Research Center “Pushchino Scientific Center for Biological Research, Russian Academy of Sciences”, Institute of Cell Biophysics of the Russian Academy of Sciences, 142290 Pushchino, Russia
- Correspondence: (E.G.V.); (E.A.T.)
| | - Egor A. Turovsky
- Federal Research Center “Pushchino Scientific Center for Biological Research, Russian Academy of Sciences”, Institute of Cell Biophysics of the Russian Academy of Sciences, 142290 Pushchino, Russia
- Correspondence: (E.G.V.); (E.A.T.)
| | - Valentina A. Babenko
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.A.B.); (E.Y.P.)
- V.I. Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, 117997 Moscow, Russia
| | - Egor Y. Plotnikov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (V.A.B.); (E.Y.P.)
- V.I. Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, 117997 Moscow, Russia
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Mechanisms Underlying the Protective Effect of the Peroxiredoxin-6 Are Mediated via the Protection of Astrocytes during Ischemia/Reoxygenation. Int J Mol Sci 2021; 22:ijms22168805. [PMID: 34445509 PMCID: PMC8396200 DOI: 10.3390/ijms22168805] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 12/12/2022] Open
Abstract
Ischemia-like conditions reflect almost the entire spectrum of events that occur during cerebral ischemia, including the induction of oxidative stress, Ca2+ overload, glutamate excitotoxicity, and activation of necrosis and apoptosis in brain cells. Mechanisms for the protective effects of the antioxidant enzyme peroxiredoxin-6 (Prx-6) on hippocampal cells during oxygen-glucose deprivation/reoxygenation (OGD/R) were investigated. Using the methods of fluorescence microscopy, inhibitory analysis, vitality tests and PCR, it was shown that 24-h incubation of mixed hippocampal cell cultures with Prx-6 does not affect the generation of a reversible phase of a OGD-induced rise in Ca2+ ions in cytosol ([Ca2+]i), but inhibits a global increase in [Ca2+]i in astrocytes completely and in neurons by 70%. In addition, after 40 min of OGD, cell necrosis is suppressed, especially in the astrocyte population. This effect is associated with the complex action of Prx-6 on neuroglial networks. As an antioxidant, Prx-6 has a more pronounced and astrocyte-directed effect, compared to the exogenous antioxidant vitamin E (Vit E). Prx-6 inhibits ROS production in mitochondria by increasing the antioxidant capacity of cells and altering the expression of genes encoding redox status proteins. Due to the close bond between [Ca2+]i and intracellular ROS, this effect of Prx-6 is one of its protective mechanisms. Moreover, Prx-6 effectively suppresses not only necrosis, but also apoptosis during OGD and reoxygenation. Incubation with Prx-6 leads to activation of the basic expression of genes encoding protective kinases—PI3K, CaMKII, PKC, anti-apoptotic proteins—Stat3 and Bcl-2, while inhibiting the expression of signaling kinases and factors involved in apoptosis activation—Ikk, Src, NF-κb, Caspase-3, p53, Fas, etc. This effect on the basic expression of the genome leads to the cell preconditions, which is expressed in the inhibition of caspase-3 during OGD/reoxygenation. A significant effect of Prx-6 is directed on suppression of the level of pro-inflammatory cytokine IL-1β and factor TNFα, as well as genes encoding NMDA- and kainate receptor subunits, which was established for the first time for this antioxidant enzyme. The protective effect of Prx-6 is due to its antioxidant properties, since mutant Prx-6 (mutPrx-6, Prx6-C47S) leads to polar opposite effects, contributing to oxidative stress, activation of apoptosis and cell death through receptor action on TLR4.
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Role of Satb1 and Satb2 Transcription Factors in the Glutamate Receptors Expression and Ca 2+ Signaling in the Cortical Neurons In Vitro. Int J Mol Sci 2021; 22:ijms22115968. [PMID: 34073140 PMCID: PMC8198236 DOI: 10.3390/ijms22115968] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 05/28/2021] [Accepted: 05/28/2021] [Indexed: 01/17/2023] Open
Abstract
Transcription factors Satb1 and Satb2 are involved in the processes of cortex development and maturation of neurons. Alterations in the expression of their target genes can lead to neurodegenerative processes. Molecular and cellular mechanisms of regulation of neurotransmission by these transcription factors remain poorly understood. In this study, we have shown that transcription factors Satb1 and Satb2 participate in the regulation of genes encoding the NMDA-, AMPA-, and KA- receptor subunits and the inhibitory GABA(A) receptor. Deletion of gene for either Satb1 or Satb2 homologous factors induces the expression of genes encoding the NMDA receptor subunits, thereby leading to higher amplitudes of Ca2+-signals in neurons derived from the Satb1-deficient (Satb1fl/+ * NexCre/+) and Satb1-null mice (Satb1fl/fl * NexCre/+) in response to the selective agonist reducing the EC50 for the NMDA receptor. Simultaneously, there is an increase in the expression of the Gria2 gene, encoding the AMPA receptor subunit, thus decreasing the Ca2+-signals of neurons in response to the treatment with a selective agonist (5-Fluorowillardiine (FW)). The Satb1 deletion increases the sensitivity of the KA receptor to the agonist (domoic acid), in the cortical neurons of the Satb1-deficient mice but decreases it in the Satb1-null mice. At the same time, the Satb2 deletion decreases Ca2+-signals and the sensitivity of the KA receptor to the agonist in neurons from the Satb1-null and the Satb1-deficient mice. The Satb1 deletion affects the development of the inhibitory system of neurotransmission resulting in the suppression of the neuron maturation process and switching the GABAergic responses from excitatory to inhibitory, while the Satb2 deletion has a similar effect only in the Satb1-null mice. We show that the Satb1 and Satb2 transcription factors are involved in the regulation of the transmission of excitatory signals and inhibition of the neuronal network in the cortical cell culture.
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Khozhai LI, Otellin VA. Parvalbumin Expression in Rat Subventricular
Zone as Affected by Acute Hypoxia during Early Postnatal Ontogeny. J EVOL BIOCHEM PHYS+ 2020. [DOI: 10.1134/s0022093020060058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Turovskaya MV, Epifanova EA, Tarabykin VS, Babaev AA, Turovsky EA. Interleukin-10 restores glutamate receptor-mediated Ca 2+-signaling in brain circuits under loss of Sip1 transcription factor. Int J Neurosci 2020; 132:114-125. [PMID: 32727246 DOI: 10.1080/00207454.2020.1803305] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE This study aimed to investigate the connection between the mutation of the Sip1 transcription factor and impaired Ca2+-signaling, which reflects changes in neurotransmission in the cerebral cortex in vitro. METHODS We used mixed neuroglial cortical cell cultures derived from Sip1 mutant mice. The cells were loaded with a fluorescent ratiometric calcium-sensitive probe Fura-2 AM and epileptiform activity was modeled by excluding magnesium ions from the external media or adding a GABA(A) receptor antagonist, bicuculline. Intracellular calcium dynamics were recorded using fluorescence microscopy. To identify the level of gene expression, the Real-Time PCR method was used. RESULTS It was found that cortical neurons isolated from homozygous (Sip1fl/fl) mice with the Sip1 mutation demonstrate suppressed Ca2+ signals in models of epileptiform activity in vitro. Wild-type cortical neurons are characterized by synchronous high-frequency and high-amplitude Ca2+ oscillations occurring in all neurons of the network in response to Mg2+-free medium and bicuculline. But cortical Sip1fl/fl neurons only single Ca2+ pulses or attenuated Ca2+ oscillations are recorded and only in single neurons, while most of the cell network does not respond to these stimuli. This signal deficiency of Sip1fl/fl neurons correlates with a suppressed expression level of the genes encoding the subunits of NMDA, AMPA, and KA receptors; protein kinases PKA, JNK, CaMKII; and also the transcription factor Hif1α. These negative effects were partially abolished when Sip1fl/fl neurons are grown in media with anti-inflammatory cytokine IL-10. IL-10 increases the expression of the above-mentioned genes but not to the level of expression in wild-type. At the same time, the amplitudes of Ca2+ signals increase in response to the selective agonists of NMDA, AMPA and KA receptors, and the proportion of neurons responding with Ca2+ oscillations to a Mg2+-free medium and bicuculline increases. CONCLUSION IL-10 restores neurotransmission in neuronal networks with the Sip1 mutation by regulating the expression of genes encoding signaling proteins.
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Affiliation(s)
- Maria V Turovskaya
- Laboratory of Intracellular Signaling, Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences," Russia
| | - Ekaterina A Epifanova
- Laboratory of Genetic Engineering Technologies, Lobachevsky State University of Nizhni Novgorod, Russia
| | - Victor S Tarabykin
- Laboratory of Genetic Engineering Technologies, Lobachevsky State University of Nizhni Novgorod, Russia
| | - Alexei A Babaev
- Laboratory of Genetic Engineering Technologies, Lobachevsky State University of Nizhni Novgorod, Russia
| | - Egor A Turovsky
- Laboratory of Intracellular Signaling, Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences," Russia.,Laboratory of Genetic Engineering Technologies, Lobachevsky State University of Nizhni Novgorod, Russia
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Turovskaya MV, Gaidin SG, Vedunova MV, Babaev AA, Turovsky EA. BDNF Overexpression Enhances the Preconditioning Effect of Brief Episodes of Hypoxia, Promoting Survival of GABAergic Neurons. Neurosci Bull 2020; 36:733-760. [PMID: 32219700 PMCID: PMC7340710 DOI: 10.1007/s12264-020-00480-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 12/17/2019] [Indexed: 12/18/2022] Open
Abstract
Hypoxia causes depression of synaptic plasticity, hyperexcitation of neuronal networks, and the death of specific populations of neurons. However, brief episodes of hypoxia can promote the adaptation of cells. Hypoxic preconditioning is well manifested in glutamatergic neurons, while this adaptive mechanism is virtually suppressed in GABAergic neurons. Here, we show that brain-derived neurotrophic factor (BDNF) overexpression in neurons enhances the preconditioning effect of brief episodes of hypoxia. The amplitudes of the NMDAR- and AMPAR-mediated Ca2+ responses of glutamatergic and GABAergic neurons gradually decreased after repetitive brief hypoxia/reoxygenation cycles in cell cultures transduced with the (AAV)-Syn-BDNF-EGFP virus construct. In contrast, the amplitudes of the responses of GABAergic neurons increased in non-transduced cultures after preconditioning. The decrease of the amplitudes in GABAergic neurons indicated the activation of mechanisms of hypoxic preconditioning. Preconditioning suppressed apoptotic or necrotic cell death. This effect was most pronounced in cultures with BDNF overexpression. Knockdown of BDNF abolished the effect of preconditioning and promoted the death of GABAergic neurons. Moreover, the expression of the anti-apoptotic genes Stat3, Socs3, and Bcl-xl substantially increased 24 h after hypoxic episodes in the transduced cultures compared to controls. The expression of genes encoding the pro-inflammatory cytokines IL-10 and IL-6 also increased. In turn, the expression of pro-apoptotic (Bax, Casp-3, and Fas) and pro-inflammatory (IL-1β and TNFα) genes decreased after hypoxic episodes in cultures with BDNF overexpression. Inhibition of vesicular BDNF release abolished its protective action targeting inhibition of the oxygen-glucose deprivation (OGD)-induced [Ca2+]i increase in GABAergic and glutamatergic neurons, thus promoting their death. Bafilomycin A1, Brefeldin A, and tetanus toxin suppressed vesicular release (including BDNF) and shifted the gene expression profile towards excitotoxicity, inflammation, and apoptosis. These inhibitors of vesicular release abolished the protective effects of hypoxic preconditioning in glutamatergic neurons 24 h after hypoxia/reoxygenation cycles. This finding indicates a significant contribution of vesicular BDNF release to the development of the mechanisms of hypoxic preconditioning. Thus, our results demonstrate that BDNF plays a pivotal role in the activation and enhancement of the preconditioning effect of brief episodes of hypoxia and promotes tolerance of the most vulnerable populations of GABAergic neurons to hypoxia/ischemia.
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Affiliation(s)
- M V Turovskaya
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Pushchino, Russia
| | - S G Gaidin
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Pushchino, Russia
| | - M V Vedunova
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - A A Babaev
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - E A Turovsky
- Institute of Cell Biophysics of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Pushchino, Russia.
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Teplov IY, Tuleukhanov ST, Zinchenko VP. Regulation of Action Potential Frequency and Amplitude by T-type Ca2+ Channel During Spontaneous Synchronous Activity of Hippocampal Neurons. Biophysics (Nagoya-shi) 2018. [DOI: 10.1134/s0006350918040206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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