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Bedner P, Steinhäuser C. Role of Impaired Astrocyte Gap Junction Coupling in Epileptogenesis. Cells 2023; 12:1669. [PMID: 37371139 DOI: 10.3390/cells12121669] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/25/2023] [Accepted: 06/19/2023] [Indexed: 06/29/2023] Open
Abstract
The gap-junction-coupled astroglial network plays a central role in the regulation of neuronal activity and synchronisation, but its involvement in the pathogenesis of neuronal diseases is not yet understood. Here, we present the current state of knowledge about the impact of impaired glial coupling in the development and progression of epilepsy and discuss whether astrocytes represent alternative therapeutic targets. We focus mainly on temporal lobe epilepsy (TLE), which is the most common form of epilepsy in adults and is characterised by high therapy resistance. Functional data from TLE patients and corresponding experimental models point to a complete loss of astrocytic coupling, but preservation of the gap junction forming proteins connexin43 and connexin30 in hippocampal sclerosis. Several studies further indicate that astrocyte uncoupling is a causal event in the initiation of TLE, as it occurs very early in epileptogenesis, clearly preceding dysfunctional changes in neurons. However, more research is needed to fully understand the role of gap junction channels in epilepsy and to develop safe and effective therapeutic strategies targeting astrocytes.
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Affiliation(s)
- Peter Bedner
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
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2
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Borges FS, Gabrick EC, Protachevicz PR, Higa GSV, Lameu EL, Rodriguez PXR, Ferraz MSA, Szezech JD, Batista AM, Kihara AH. Intermittency properties in a temporal lobe epilepsy model. Epilepsy Behav 2023; 139:109072. [PMID: 36652897 DOI: 10.1016/j.yebeh.2022.109072] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/22/2022] [Accepted: 12/26/2022] [Indexed: 01/18/2023]
Abstract
Neuronal synchronization is important for communication between brain regions and plays a key role in learning. However, changes in connectivity can lead to hyper-synchronized states related to epileptic seizures that occur intermittently with asynchronous states. The activity-regulated cytoskeleton-associated protein (ARC) is related to synaptic alterations which can lead to epilepsy. Induction of status epilepticus in rodent models causes the appearance of intense ARC immunoreactive neurons (IAINs), which present a higher number of connections and conductance intensity than non-IAINs. This alteration might contribute to abnormal epileptic seizure activity. In this work, we investigated how IAINs connectivity influences the firing pattern and synchronization in neural networks. Firstly, we showed the appearance of synchronized burst patterns due to the emergence of IAINs. Second, we described how the increase of IAINs connectivity favors the appearance of intermittent up and down activities associated with synchronous bursts and asynchronous spikes, respectively. Once the intermittent activity was properly characterized, we applied the optogenetics control of the high synchronous activities in the intermittent regime. To do this, we considered that 1% of neurons were transfected and became photosensitive. We observed that optogenetics methods to control synchronized burst patterns are effective when IAINs are chosen as photosensitive, but not effective in non-IAINs. Therefore, our analyses suggest that IAINs play a pivotal role in both the generation and suppression of highly synchronized activities.
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Affiliation(s)
- F S Borges
- Department of Physiology and Pharmacology, State University of New York Downstate Health Sciences University, Brooklyn, NY, USA; Center for Mathematics, Computation, and Cognition, Federal University of ABC, São Bernardo do Campo, SP, Brazil.
| | - E C Gabrick
- Graduate in Science Program - Physics, State University of Ponta Grossa, Ponta Grossa, PR, Brazil
| | - P R Protachevicz
- Institute of Physics, University of São Paulo, São Paulo, SP, Brazil
| | - G S V Higa
- Center for Mathematics, Computation, and Cognition, Federal University of ABC, São Bernardo do Campo, SP, Brazil; Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil
| | - E L Lameu
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - P X R Rodriguez
- Center for Mathematics, Computation, and Cognition, Federal University of ABC, São Bernardo do Campo, SP, Brazil; Faculty of Medicine, University of Bonn, Bonn, Germany
| | - M S A Ferraz
- Center for Mathematics, Computation, and Cognition, Federal University of ABC, São Bernardo do Campo, SP, Brazil
| | - J D Szezech
- Graduate in Science Program - Physics, State University of Ponta Grossa, Ponta Grossa, PR, Brazil; Department of Mathematics and Statistics, State University of Ponta Grossa, Ponta Grossa, PR, Brazil
| | - A M Batista
- Graduate in Science Program - Physics, State University of Ponta Grossa, Ponta Grossa, PR, Brazil; Institute of Physics, University of São Paulo, São Paulo, SP, Brazil; Department of Mathematics and Statistics, State University of Ponta Grossa, Ponta Grossa, PR, Brazil
| | - A H Kihara
- Center for Mathematics, Computation, and Cognition, Federal University of ABC, São Bernardo do Campo, SP, Brazil.
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3
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Andrioli A, Fabene PF, Mudò G, Barresi V, Di Liberto V, Frinchi M, Bentivoglio M, Condorelli DF. Downregulation of the Astroglial Connexin Expression and Neurodegeneration after Pilocarpine-Induced Status Epilepticus. Int J Mol Sci 2022; 24:ijms24010023. [PMID: 36613467 PMCID: PMC9819917 DOI: 10.3390/ijms24010023] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
Astrocytic networks and gap junctional communication mediated by connexins (Cxs) have been repeatedly implicated in seizures, epileptogenesis, and epilepsy. However, the effect of seizures on Cx expression is controversial. The present study focused on the response of Cxs to status epilepticus (SE), which is in turn an epileptogenic insult. The expression of neuronal Cx36 and astrocytic Cx30 and Cx43 mRNAs was investigated in the brain of rats in the first day after pilocarpine-induced SE. In situ hybridization revealed a progressive decrease in Cx43 and Cx30 mRNA levels, significantly marked 24 h after SE onset in neocortical areas and the hippocampus, and in most thalamic domains, whereas Cx36 mRNA did not exhibit obvious changes. Regional evaluation with quantitative real-time-RT-PCR confirmed Cx43 and Cx30 mRNA downregulation 24 h after SE, when ongoing neuronal cell death was found in the same brain regions. Immunolabeling showed at the same time point marked a decrease in Cx43, microglia activation, and interleukin-1β induction in some microglial cells. The data showed a transient downregulation of astroglial Cxs in the cortical and thalamic areas in which SE triggers neurodegenerative events in concomitance with microglia activation and cytokine expression. This could potentially represent a protective response of neuroglial networks to SE-induced acute damage.
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Affiliation(s)
- Anna Andrioli
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy
| | - Paolo Francesco Fabene
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy
- Verona Unit, National Institute of Neuroscience (INN), 37129 Verona, Italy
| | - Giuseppa Mudò
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BiND), University of Palermo, 90133 Palermo, Italy
| | - Vincenza Barresi
- Unit of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
| | - Valentina Di Liberto
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BiND), University of Palermo, 90133 Palermo, Italy
| | - Monica Frinchi
- Department of Biomedicine, Neuroscience and Advanced Diagnostic (BiND), University of Palermo, 90133 Palermo, Italy
| | - Marina Bentivoglio
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy
- Verona Unit, National Institute of Neuroscience (INN), 37129 Verona, Italy
| | - Daniele Filippo Condorelli
- Unit of Medical Biochemistry, Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
- Correspondence:
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4
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Ferraz MSA, Kihara AH. Beyond randomness: Evaluating measures of information entropy in binary series. Phys Rev E 2022; 105:044101. [PMID: 35590660 DOI: 10.1103/physreve.105.044101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 03/09/2022] [Indexed: 06/15/2023]
Abstract
The enormous amount of currently available data demands efforts to extract meaningful information. For this purpose, different measurements are applied, including Shannon's entropy, permutation entropy, and the Lempel-Ziv complexity. These methods have been used in many applications, such as pattern recognition, series classification, and several other areas (e.g., physical, financial, and biomedical). Data in these applications are often presented in binary series with temporal correlations. Herein, we compare the measures of information entropy in binary series conveying short- and long-range temporal correlations characterized by the Hurst exponent H. Combining numerical and analytical approaches, we scrutinize different methods that were not efficient in detecting temporal correlations. To surpass this limitation, we propose a measure called the binary permutation index (BPI). We will demonstrate that BPI efficiently discriminates patterns embedded in the series, offering advantages over previous methods. Subsequently, we collect stock market time series and rain precipitation data as well as perform in vivo electrophysiological recordings in the hippocampus of an experimental animal model of temporal lobe epilepsy, in which the BPI application in both public open source and experimental data is demonstrated. An index is proposed to evaluate information entropy, allowing the ability to discriminate randomness and extract meaningful information in binary time series.
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Affiliation(s)
- Mariana Sacrini Ayres Ferraz
- Centro de Matemática, Computação e Cognição (CMCC), Universidade Federal do ABC (UFABC), São Bernardo do Campo, São Paulo, Brazil
| | - Alexandre Hiroaki Kihara
- Centro de Matemática, Computação e Cognição (CMCC), Universidade Federal do ABC (UFABC), São Bernardo do Campo, São Paulo, Brazil
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Gouveia FV, Germann J, Oliveira CC, Castro MC, Antunes GF, Gomes GCV, Pinto TRC, Martinez RCR, Valle AC. Transcranial Direct Current Stimulation Reduces Anxiety, Depression and Plasmatic Corticosterone in a Rat Model of Atypical Generalized Epilepsy. Neuroscience 2021; 480:32-41. [PMID: 34774711 DOI: 10.1016/j.neuroscience.2021.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/22/2021] [Accepted: 11/02/2021] [Indexed: 11/30/2022]
Abstract
Affective disorders (i.e. anxiety and depression) are commonly observed in patients with epilepsy and induce seizure aggravation. Animal models of epilepsy that exhibit affective disorder features are essential in developing new neuromodulatory treatments. GEAS-W rats (Generalized Epilepsy with Absence Seizures, Wistar background) are an inbred model of generalized epilepsy showing spontaneous spike-wave discharges concomitant with immobility. Transcranial Direct Current Stimulation (tDCS) is a safe non-invasive neuromodulatory therapy used to modulate dysfunctional circuitries frequently and successfully applied in affective disorders for symptom alleviation. Here we investigated anxiolytic and antidepressant effects of tDCS in GEAS-W rats and the role of corticosterone as a possible mechanism of action. GEAS-W and Wistar rats were randomly divided into control, sham-tDCS and active-tDCS groups. Both tDCS groups received 15 sessions of sham or active-tDCS (1 mA, cathode). Behavioural tests included the Open Field and Forced Swimming tests followed by corticosterone analysis. We observed a main effect of treatment and a significant treatment by strain interaction on anxiety-like and depressive-like behaviours, with active-tDCS GEAS-W rats entering the center of the open field more often and showing less immobility in the forced swimming test. Furthermore, there was a main effect of treatment on corticosterone with active-tDCS animals showing marked reduction in plasmatic levels. This study described preclinical evidence to support tDCS treatment of affective disorders in epilepsy and highlights corticosterone as a possible mechanism of action.
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Affiliation(s)
- Flavia Venetucci Gouveia
- Program in Neuroscience and Mental Health, Hospital for Sick Children Research Institute, Toronto, Canada; Division of Neuroscience, Sírio-Libanês Hospital, São Paulo, Brazil.
| | - Jürgen Germann
- Division of Neurosurgery, Department of Surgery, University Health Network and University of Toronto, Toronto, Canada
| | | | - Marina C Castro
- Division of Neuroscience, Sírio-Libanês Hospital, São Paulo, Brazil
| | - Geiza F Antunes
- Division of Neuroscience, Sírio-Libanês Hospital, São Paulo, Brazil
| | - Gisele C V Gomes
- Laboratory of Neuroscience LIM 01, Department of Pathology, University of Sao Paulo, School of Medicine, São Paulo, Brazil
| | - Tais R C Pinto
- Laboratory of Neuroscience LIM 01, Department of Pathology, University of Sao Paulo, School of Medicine, São Paulo, Brazil
| | - Raquel C R Martinez
- Division of Neuroscience, Sírio-Libanês Hospital, São Paulo, Brazil; LIM 23, Institute of Psychiatry, University of Sao Paulo, School of Medicine, São Paulo, Brazil.
| | - Angela C Valle
- Laboratory of Neuroscience LIM 01, Department of Pathology, University of Sao Paulo, School of Medicine, São Paulo, Brazil
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Astrocytic Connexin43 Channels as Candidate Targets in Epilepsy Treatment. Biomolecules 2020; 10:biom10111578. [PMID: 33233647 PMCID: PMC7699773 DOI: 10.3390/biom10111578] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022] Open
Abstract
In epilepsy research, emphasis is put on exploring non-neuronal targets such as astrocytic proteins, since many patients remain pharmacoresistant to current treatments, which almost all target neuronal mechanisms. This paper reviews available data on astrocytic connexin43 (Cx43) signaling in seizures and epilepsy. Cx43 is a widely expressed transmembrane protein and the constituent of gap junctions (GJs) and hemichannels (HCs), allowing intercellular and extracellular communication, respectively. A plethora of research papers show altered Cx43 mRNA levels, protein expression, phosphorylation state, distribution and/or functional coupling in human epileptic tissue and experimental models. Human Cx43 mutations are linked to seizures as well, as 30% of patients with oculodentodigital dysplasia (ODDD), a rare genetic condition caused by mutations in the GJA1 gene coding for Cx43 protein, exhibit neurological symptoms including seizures. Cx30/Cx43 double knock-out mice show increased susceptibility to evoked epileptiform events in brain slices due to impaired GJ-mediated redistribution of K+ and glutamate and display a higher frequency of spontaneous generalized chronic seizures in an epilepsy model. Contradictory, Cx30/Cx43 GJs can traffic nutrients to high-energy demanding neurons and initiate astrocytic Ca2+ waves and hyper synchronization, thereby supporting proconvulsant effects. The general connexin channel blocker carbenoxolone and blockers from the fenamate family diminish epileptiform activity in vitro and improve seizure outcome in vivo. In addition, interventions with more selective peptide inhibitors of HCs display anticonvulsant actions. To conclude, further studies aiming to disentangle distinct roles of HCs and GJs are necessary and tools specifically targeting Cx43 HCs may facilitate the search for novel epilepsy treatments.
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7
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Effect of ovarian stimulation on the expression of piRNA pathway proteins. PLoS One 2020; 15:e0232629. [PMID: 32365144 PMCID: PMC7197780 DOI: 10.1371/journal.pone.0232629] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/17/2020] [Indexed: 12/11/2022] Open
Abstract
PIWI-interacting RNAs (piRNAs) play an important role in gametogenesis, fertility and embryonic development. The current study investigated the effect of different doses of pregnant mare serum gonadotrophin/human chorionic gonadotrophin (PMSG/hCG) and repeated ovarian stimulation (OS) on the expression of the Mili, Miwi, Mael, Tdrd1, Tdrd9, qnd Mitopld genes, which have crucial roles in the biogenesis and function of piRNAs. Here, we found that after treatment with 7.5 I.U. PMSG/hCG and two repeated rounds of OS, both the mRNA and protein levels of Tdrd9, Tdrd1 and Mael showed the greatest decrease in the ovarian tissue, but the plasma E2 levels showed the strongest increases (p<0.05). However, we found that the Mitopld, Miwi and Mili gene levels were decreased significantly after treatment with 12.5 I.U. PMSG/hCG. Our results suggested that exogenous gonadotropin administration leads to a significant decrease in the expression of the Mili, Miwi, Mael, Tdrd1, Tdrd9 and Mitopld genes, which are critically important in the piRNA pathway, and the changes in the expression levels of Tdrd9, Tdrd1 and Mael may be associated with plasma E2 levels. New comprehensive studies are needed to reduce the potential effects of OS on the piRNA pathway, which silences transposable elements and maintains genome integrity, and to contribute to the safety of OS.
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8
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Wu XL, Ma DM, Zhang W, Zhou JS, Huo YW, Lu M, Tang FR. Cx36 in the mouse hippocampus during and after pilocarpine-induced status epilepticus. Epilepsy Res 2018; 141:64-72. [PMID: 29476948 DOI: 10.1016/j.eplepsyres.2018.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 01/24/2018] [Accepted: 02/13/2018] [Indexed: 12/24/2022]
Abstract
Gap junctions play an important role in the synchronization activity of coupled cells. Hippocampal inhibitory interneurons are involved in epileptogenesis and seizure activity, and express gap junction protein connexin (Cx) 36. Cx36 is also localized in the axons (mossy fibers) of granule cells in the dentate gyrus. While it has been documented that Cx36 is involved in epileptogenesis, there are still controversies regarding the expression levels of Cx36 at different developmental stages of human and animal models of epileptogenesis. In this study, the expression of Cx36 was investigated in the mouse hippocampus at 1 h, 4 h during pilocarpine-induced status epilepticus (PISE) and 1 week, 2 months after PISE. We found that Cx36 was down-regulated in neurons at different time points during and after PISE, whereas it was increased significantly in the stratum lucidum of CA3 area at 2 months after PISE. Double immunofluorescence indicated that Cx36 was localized in parvalbumin (PV) immunopositive interneuron in CA1 area and in mossy fibers and their terminals in the stratum lucidum of CA3 area. It suggests that decreased expression of Cx36 in interneurons may be related to less effective inhibitory control of excitatory activity of hippocampal principal neurons. However, the increased Cx36 immunopositive product in mossy fibers at the chronic stage after PISE may enhance the contacts between granule cells in the dentate gyrus and pyramidal neurons in CA3 area. The two different changes of Cx36 may be implicated in the epileptogenesis.
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Affiliation(s)
- X L Wu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an, Shaanxi 710061, China
| | - D M Ma
- Department of Thoracic Surgery, The Ninth Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710054, China
| | - W Zhang
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an, Shaanxi 710061, China
| | - J S Zhou
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an, Shaanxi 710061, China
| | - Y W Huo
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an, Shaanxi 710061, China
| | - M Lu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an, Shaanxi 710061, China
| | - F R Tang
- Radiation Physiology Laboratory, Singapore Nuclear Research and Safety Initiative (SNRSI), National University of Singapore, 1 CREATE Way #04-01, CREATE Tower 138602, Singapore.
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Optimizing information processing in neuronal networks beyond critical states. PLoS One 2017; 12:e0184367. [PMID: 28922366 PMCID: PMC5603180 DOI: 10.1371/journal.pone.0184367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 08/22/2017] [Indexed: 11/19/2022] Open
Abstract
Critical dynamics have been postulated as an ideal regime for neuronal networks in the brain, considering optimal dynamic range and information processing. Herein, we focused on how information entropy encoded in spatiotemporal activity patterns may vary in critical networks. We employed branching process based models to investigate how entropy can be embedded in spatiotemporal patterns. We determined that the information capacity of critical networks may vary depending on the manipulation of microscopic parameters. Specifically, the mean number of connections governed the number of spatiotemporal patterns in the networks. These findings are compatible with those of the real neuronal networks observed in specific brain circuitries, where critical behavior is necessary for the optimal dynamic range response but the uncertainty provided by high entropy as coded by spatiotemporal patterns is not required. With this, we were able to reveal that information processing can be optimized in neuronal networks beyond critical states.
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10
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Kinjo ER, Rodríguez PXR, Dos Santos BA, Higa GSV, Ferraz MSA, Schmeltzer C, Rüdiger S, Kihara AH. New Insights on Temporal Lobe Epilepsy Based on Plasticity-Related Network Changes and High-Order Statistics. Mol Neurobiol 2017; 55:3990-3998. [PMID: 28555345 DOI: 10.1007/s12035-017-0623-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 05/16/2017] [Indexed: 12/21/2022]
Abstract
Epilepsy is a disorder of the brain characterized by the predisposition to generate recurrent unprovoked seizures, which involves reshaping of neuronal circuitries based on intense neuronal activity. In this review, we first detailed the regulation of plasticity-associated genes, such as ARC, GAP-43, PSD-95, synapsin, and synaptophysin. Indeed, reshaping of neuronal connectivity after the primary, acute epileptogenesis event increases the excitability of the temporal lobe. Herein, we also discussed the heterogeneity of neuronal populations regarding the number of synaptic connections, which in the theoretical field is commonly referred as degree. Employing integrate-and-fire neuronal model, we determined that in addition to increased synaptic strength, degree correlations might play essential and unsuspected roles in the control of network activity. Indeed, assortativity, which can be described as a condition where high-degree correlations are observed, increases the excitability of neural networks. In this review, we summarized recent topics in the field, and data were discussed according to newly developed or unusual tools, as provided by mathematical graph analysis and high-order statistics. With this, we were able to present new foundations for the pathological activity observed in temporal lobe epilepsy.
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Affiliation(s)
- Erika Reime Kinjo
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Pedro Xavier Royero Rodríguez
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Bianca Araújo Dos Santos
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Guilherme Shigueto Vilar Higa
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Mariana Sacrini Ayres Ferraz
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Christian Schmeltzer
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
- Institute of Physics, Humboldt University at Berlin, Berlin, Germany
| | - Sten Rüdiger
- Institute of Physics, Humboldt University at Berlin, Berlin, Germany
| | - Alexandre Hiroaki Kihara
- Laboratório de Neurogenética, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil.
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil.
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11
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Kinjo ER, Higa GSV, Santos BA, de Sousa E, Damico MV, Walter LT, Morya E, Valle AC, Britto LRG, Kihara AH. Pilocarpine-induced seizures trigger differential regulation of microRNA-stability related genes in rat hippocampal neurons. Sci Rep 2016; 6:20969. [PMID: 26869208 PMCID: PMC4751485 DOI: 10.1038/srep20969] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 01/14/2016] [Indexed: 11/17/2022] Open
Abstract
Epileptogenesis in the temporal lobe elicits regulation of gene expression and protein translation, leading to reorganization of neuronal networks. In this process, miRNAs were described as being regulated in a cell-specific manner, although mechanistics of miRNAs activity are poorly understood. The specificity of miRNAs on their target genes depends on their intracellular concentration, reflecting the balance of biosynthesis and degradation. Herein, we confirmed that pilocarpine application promptly (<30 min) induces status epilepticus (SE) as revealed by changes in rat electrocorticogram particularly in fast-beta range (21–30 Hz). SE simultaneously upregulated XRN2 and downregulated PAPD4 gene expression in the hippocampus, two genes related to miRNA degradation and stability, respectively. Moreover, SE decreased the number of XRN2-positive cells in the hilus, while reduced the number of PAPD4-positive cells in CA1. XRN2 and PAPD4 levels did not change in calretinin- and CamKII-positive cells, although it was possible to determine that PAPD4, but not XRN2, was upregulated in parvalbumin-positive cells, revealing that SE induction unbalances the accumulation of these functional-opposed proteins in inhibitory interneurons that directly innervate distinct domains of pyramidal cells. Therefore, we were able to disclose a possible mechanism underlying the differential regulation of miRNAs in specific neurons during epileptogenesis.
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Affiliation(s)
- Erika R Kinjo
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Guilherme S V Higa
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil.,Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Bianca A Santos
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Erica de Sousa
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Marcio V Damico
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Lais T Walter
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Edgard Morya
- Programa de Neuroengenharia, Instituto Internacional de Neurociências Edmond e Lily Safra, ISD, Macaíba, RN, Brazil
| | - Angela C Valle
- Laboratório de Neurociências, LIM 01, Departamento de Patologia, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Luiz R G Britto
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Alexandre H Kihara
- Núcleo de Cognição e Sistemas Complexos, Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil.,Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
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Laura MC, Xóchitl FP, Anne S, Alberto MV. Analysis of connexin expression during seizures induced by 4-aminopyridine in the rat hippocampus. J Biomed Sci 2015; 22:69. [PMID: 26268619 PMCID: PMC4535691 DOI: 10.1186/s12929-015-0176-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 08/04/2015] [Indexed: 12/13/2022] Open
Abstract
Background In epilepsy, seizures are generated by abnormal synchronous activity in neurons. In the rat hippocampus (HIP), epileptiform activity has been found to be associated with gap junctions (GJs). GJs are formed by the combination of two hemichannels, each composed of six connexins. At low doses, the convulsive drug 4-aminopyridine (4-AP) produces epileptiform activity without affecting glutamate levels; therefore, GJs could participate in its effect. Based on this argument, in this study, the expression of Cx 32, Cx 36 and Cx 43 protein and mRNA in the HIP of rats treated with 4-AP was evaluated. The evaluation of connexins was carried out by chemifluorescent immunoassay, semiquantitative RT-PCR and immunofluorescence to detect the amount and distribution of connexins and of cellular markers in the HIP and dentate gyrus (DG) of animals treated with NaCl and 4-AP in the right entorhinal cortex. In these animals, convulsive behavior and EEG signals were analyzed. Results The animals treated with 4-AP showed convulsive behavior and epileptiform activity 60 min after the administration. A significant increase in the protein expression of Cx 32, Cx 36 and Cx 43 was found in the HIP contralateral and ipsilateral to the site of 4-AP administration. A trend toward an increase in the mRNA of Cx 32 and Cx 43 was also found. An increase in the cellular density of Cx 32 and Cx 43 was found in the right HIP and DG, and an increase in the cellular density of oligodendrocytes in the DG and a decrease in the number of cells marked with NeuN were observed in the left HIP. Conclusions Cx 32 and Cx 43 associated with oligodendrocytes and astrocytes had an important role in the first stages of seizures induced by 4-AP, whereas Cx36 localized to neurons could be associated with later stages. Additionally, these results contribute to our understanding of the role of connexins in acute seizures and allow us to direct our efforts to other new anticonvulsant strategies for seizure treatment.
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Affiliation(s)
- Medina-Ceja Laura
- Laboratory of Neurophysiology and Neurochemistry, Department of Cellular and Molecular Biology, CUCBA,University of Guadalajara, Camino Ing. R. Padilla Sánchez 2100, Las Agujas, Nextipac, Zapopan, Jalisco, Mexico.
| | - Flores-Ponce Xóchitl
- Laboratory of Neurophysiology and Neurochemistry, Department of Cellular and Molecular Biology, CUCBA,University of Guadalajara, Camino Ing. R. Padilla Sánchez 2100, Las Agujas, Nextipac, Zapopan, Jalisco, Mexico.
| | - Santerre Anne
- Laboratory of Molecular Biomarkers and Molecular Genetic, Department of Cellular and Molecular Biology, CUCBA, University of Guadalajara, Jalisco, Mexico.
| | - Morales-Villagrán Alberto
- Laboratory of Neurophysiology and Neurochemistry, Department of Cellular and Molecular Biology, CUCBA,University of Guadalajara, Camino Ing. R. Padilla Sánchez 2100, Las Agujas, Nextipac, Zapopan, Jalisco, Mexico.
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