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Li H, Hu B, Zhang HP, Boyle CA, Lei S. Roles of K + and cation channels in ORL-1 receptor-mediated depression of neuronal excitability and epileptic activities in the medial entorhinal cortex. Neuropharmacology 2019; 151:144-158. [PMID: 30998945 PMCID: PMC6500758 DOI: 10.1016/j.neuropharm.2019.04.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 03/24/2019] [Accepted: 04/13/2019] [Indexed: 02/05/2023]
Abstract
Nociceptin (NOP) is an endogenous opioid-like peptide that selectively activates the opioid receptor-like (ORL-1) receptors. The entorhinal cortex (EC) is closely related to temporal lobe epilepsy and expresses high densities of ORL-1 receptors. However, the functions of NOP in the EC, especially in modulating the epileptiform activity in the EC, have not been determined. We demonstrated that activation of ORL-1 receptors remarkably inhibited the epileptiform activity in entorhinal slices induced by application of picrotoxin or by deprivation of extracellular Mg2+. NOP-mediated depression of epileptiform activity was independent of synaptic transmission in the EC, but mediated by inhibition of neuronal excitability in the EC. NOP hyperpolarized entorhinal neurons via activation of K+ channels and inhibition of cation channels. Whereas application of Ba2+ at 300 μM which is effective for the inward rectifier K+ (Kir) channels slightly inhibited NOP-induced hyperpolarization, the current-voltage (I-V) curve of the net currents induced by NOP was linear without showing inward rectification. However, a role of NOP-induced inhibition of cation channels was revealed after inhibition of Kir channels by Ba2+. Furthermore, NOP-mediated augmentation of membrane currents was differently affected by application of the blockers selective for distinct subfamilies of Kir channels. Whereas SCH23390 or ML133 blocked NOP-induced augmentation of membrane currents at negative potentials, application of tertiapin-Q exerted no actions on NOP-induced alteration of membrane currents. Our results demonstrated a novel cellular and molecular mechanism whereby activation of ORL-1 receptors depresses epilepsy.
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Affiliation(s)
- Huiming Li
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58203, USA
| | - Binqi Hu
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58203, USA
| | - Hao-Peng Zhang
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58203, USA
| | - Cody A Boyle
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58203, USA
| | - Saobo Lei
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58203, USA.
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Müller S, Guli X, Hey J, Einsle A, Pfanz D, Sudmann V, Kirschstein T, Köhling R. Acute epileptiform activity induced by gabazine involves proteasomal rather than lysosomal degradation of K Ca2.2 channels. Neurobiol Dis 2018; 112:79-84. [PMID: 29330041 DOI: 10.1016/j.nbd.2018.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/21/2017] [Accepted: 01/08/2018] [Indexed: 01/01/2023] Open
Abstract
Voltage-independent, Ca2+-activated K+ channels (KCa2.2, previously named SK2) are typically activated during a train of action potentials, and hence, are powerful regulators of cellular excitability by generating an afterhyperpolarizing potential (AHP) following prolonged excitation. In the acute in vitro epilepsy model induced in hippocampal brain slice preparations by exposure to the GABAA receptor blocker gabazine (GZ), the AHP was previously shown to be significantly decreased. Here, we asked the question whether KCa2.2 protein degradation occurs in this model and which pathways are involved. To this end, we applied either gabazine alone or gabazine together with inhibitors of proteasomal and lysosomal protein degradation pathways, Z-Leu-Leu-Leu-CHO (MG132) and chloroquine (CQ), respectively. Western blot analysis showed a significant decrease of total KCa2.2 protein content in GZ-treated slices which could be rescued by concomitant incubation with MG132 and CQ. Using HEK293 cells transfected with a green fluorescent protein-tagged KCa2.2 construct, we demonstrated that proteasomal rather than lysosomal degradation was involved in KCa2.2 reduction. We then recorded epileptiform afterdischarges at hippocampal Schaffer collateral-CA1 synapses and confirmed that the GZ-induced increase was significantly attenuated by both MG132 and CQ, with MG132 being significantly more effective than CQ. Epileptiform afterdischarges were almost prevented by co-application of protein degradation inhibitors. Furthermore, epileptiform afterdischarges could be re-established by using the KCa2.2 blocker UCL 1684 suggesting involvement of KCa2.2. We conclude that in GZ-induced acute epilepsy, KCa2.2 degradation by proteasomal rather than lysosomal pathways plays a major role in the generation of epileptiform afterdischarges.
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Affiliation(s)
- Steffen Müller
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Xiati Guli
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Judith Hey
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Anne Einsle
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Daniela Pfanz
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Victor Sudmann
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany.
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock, Germany
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Alves M, Gomez-Villafuertes R, Delanty N, Farrell MA, O'Brien DF, Miras-Portugal MT, Hernandez MD, Henshall DC, Engel T. Expression and function of the metabotropic purinergic P2Y receptor family in experimental seizure models and patients with drug-refractory epilepsy. Epilepsia 2017; 58:1603-1614. [PMID: 28733972 DOI: 10.1111/epi.13850] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2017] [Indexed: 12/14/2022]
Abstract
OBJECTIVE ATP is released into the extracellular space during pathologic processes including increased neuronal firing. Once released, ATP acts on P2 receptors including ionotropic P2X and metabotropic P2Y receptors, resulting in changes to glial function and neuronal network excitability. Evidence suggests an involvement of P2Y receptors in the pathogenesis of epilepsy, but there has been no systematic effort to characterize the expression and function of the P2Y receptor family during seizures and in experimental and human epilepsy. METHODS Status epilepticus was induced using either intra-amygdala kainic acid or pilocarpine to characterize the acute- and long-term changes in hippocampal P2Y expression. P2Y expression was also investigated in brain tissue from patients with temporal lobe epilepsy. Finally, we analyzed the effects of two specific P2Y agonists, ADP and UTP, on seizure severity and seizure-induced cell death. RESULTS Both intra-amygdala kainic acid and pilocarpine-induced status epilepticus increased the transcription of the uracil-sensitive P2Y receptors P2ry2 , P2ry4 , and P2ry6 and decreased the transcription of the adenine-sensitive P2Y receptors P2ry1 , P2ry12 , P2ry13 . Protein levels of P2Y1 , P2Y2 , P2Y4 , and P2Y6 were increased after status epilepticus, whereas P2Y12 expression was decreased. In the chronic phase, P2ry1 , P2ry2 , and P2ry6 transcription and P2Y1 , P2Y2 , and P2Y12 protein levels were increased with no changes for the other P2Y receptors. In hippocampal samples from patients with temporal lobe epilepsy, P2Y1 and P2Y2 protein expression was increased, whereas P2Y13 levels were lower. Demonstrating a functional contribution of P2Y receptors to seizures, central injection of ADP exacerbated seizure severity, whereas treatment with UTP decreased seizure severity during status epilepticus in mice. SIGNIFICANCE The present study is the first to establish the specific hippocampal expression profile and function of the P2Y receptor family after experimental status epilepticus and in human temporal lobe epilepsy and offers potential new targets for seizure control and disease modification.
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Affiliation(s)
- Mariana Alves
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Rosa Gomez-Villafuertes
- Department of Biochemistry and Molecular Biology IV, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
| | - Norman Delanty
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Beaumont Hospital, Beaumont, Dublin, Ireland
| | | | | | - Maria Teresa Miras-Portugal
- Department of Biochemistry and Molecular Biology IV, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
| | - Miguel Diaz Hernandez
- Department of Biochemistry and Molecular Biology IV, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
| | - David C Henshall
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Tobias Engel
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
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Epigenetics of Epileptogenesis-Evoked Upregulation of Matrix Metalloproteinase-9 in Hippocampus. PLoS One 2016; 11:e0159745. [PMID: 27505431 PMCID: PMC4978505 DOI: 10.1371/journal.pone.0159745] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 07/07/2016] [Indexed: 01/20/2023] Open
Abstract
Enhanced levels of Matrix Metalloproteinase-9 (MMP-9) have been implicated in the pathogenesis of epilepsy in humans and rodents. Lack of Mmp-9 impoverishes, whereas excess of Mmp-9 facilitates epileptogenesis. Epigenetic mechanisms driving the epileptogenesis-related upregulation of MMP-9 expression are virtually unknown. The aim of this study was to reveal these mechanisms. We analyzed hippocampi extracted from adult and pediatric patients with temporal lobe epilepsy as well as from partially and fully pentylenetetrazole kindled rats. We used a unique approach to the analysis of the kindling model results (inclusion in the analysis of rats being during kindling, and not only a group of fully kindled animals), which allowed us to separate the molecular effects exerted by the epileptogenesis from those related to epilepsy and epileptic activity. Consequently, it allowed for a disclosure of molecular mechanisms underlying causes, and not consequences, of epilepsy. Our data show that the epileptogenesis-evoked upregulation of Mmp-9 expression is regulated by removal from Mmp-9 gene proximal promoter of the two, interweaved potent silencing mechanisms–DNA methylation and Polycomb Repressive Complex 2 (PRC2)-related repression. Demethylation depends on a gradual dissociation of the DNA methyltransferases, Dnmt3a and Dnmt3b, and on progressive association of the DNA demethylation promoting protein Gadd45β to Mmp-9 proximal gene promoter in vivo. The PRC2-related mechanism relies on dissociation of the repressive transcription factor YY1 and the dissipation of the PRC2-evoked trimethylation on Lys27 of the histone H3 from the proximal Mmp-9 promoter chromatin in vivo. Moreover, we show that the DNA hydroxymethylation, a new epigenetic DNA modification, which is localized predominantly in the gene promoters and is particularly abundant in the brain, is not involved in a regulation of MMP-9 expression during the epileptogenesis in the rat hippocampus as well as in the hippocampi of pediatric and adult epileptic patients. Additionally, we have also found that despite of its transient nature, the histone modification H3S10ph is strongly and gradually accumulated during epileptogenesis in the cell nuclei and in the proximal Mmp-9 gene promoter in the hippocampus, which suggests that H3S10ph can be involved in DNA demethylation in mammals, and not only in Neurospora. The study identifies MMP-9 as the first protein coding gene which expression is regulated by DNA methylation in human epilepsy. We present a detailed epigenetic model of the epileptogenesis-evoked upregulation of MMP-9 expression in the hippocampus. To our knowledge, it is the most complex and most detailed mechanism of epigenetic regulation of gene expression ever revealed for a particular gene in epileptogenesis. Our results also suggest for the first time that dysregulation of DNA methylation found in epilepsy is a cause rather than a consequence of this condition.
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Zhang H, Cilz NI, Yang C, Hu B, Dong H, Lei S. Depression of neuronal excitability and epileptic activities by group II metabotropic glutamate receptors in the medial entorhinal cortex. Hippocampus 2015; 25:1299-313. [DOI: 10.1002/hipo.22437] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Haopeng Zhang
- Department of Basic Sciences; School of Medicine and Health Sciences, University of North Dakota; Grand Forks North Dakota
- Department of Anesthesiology; Xijing Hospital, Fourth Military Medical University; Xi'an Shaanxi Province China
| | - Nicholas I. Cilz
- Department of Basic Sciences; School of Medicine and Health Sciences, University of North Dakota; Grand Forks North Dakota
| | - Chuanxiu Yang
- Department of Basic Sciences; School of Medicine and Health Sciences, University of North Dakota; Grand Forks North Dakota
| | - Binqi Hu
- Department of Basic Sciences; School of Medicine and Health Sciences, University of North Dakota; Grand Forks North Dakota
| | - Hailong Dong
- Department of Anesthesiology; Xijing Hospital, Fourth Military Medical University; Xi'an Shaanxi Province China
| | - Saobo Lei
- Department of Basic Sciences; School of Medicine and Health Sciences, University of North Dakota; Grand Forks North Dakota
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Yang L, Zhao Y, Wang Y, Liu L, Zhang X, Li B, Cui R. The Effects of Psychological Stress on Depression. Curr Neuropharmacol 2015; 13:494-504. [PMID: 26412069 PMCID: PMC4790405 DOI: 10.2174/1570159x1304150831150507] [Citation(s) in RCA: 296] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 01/13/2015] [Accepted: 01/25/2015] [Indexed: 01/01/2023] Open
Abstract
Major depressive disorder is a serious mental disorder that profoundly affects an individual's quality of life. Although the aetiologies underlying this disorder remain unclear, an increasing attention has been focused on the influence imposed by psychological stress over depression. Despite limited animal models of psychological stress, significant progress has been made as to be explicated in this review to elucidate the physiopathology underlying depression and to treat depressive symptoms. Therefore, we will review classical models along with new methods that will enrich our knowledge of this disorder.
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Affiliation(s)
- Longfei Yang
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic
| | - Yinghao Zhao
- Department of Thoracic Surgery, Second Hospital of Jilin University, Changchun 130024, China
| | - Yicun Wang
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic
| | - Lei Liu
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic
| | - Xingyi Zhang
- Department of Thoracic Surgery, Second Hospital of Jilin University, Changchun 130024, China
| | - Bingjin Li
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic
| | - Ranji Cui
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic
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