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Zhu ZA, Li YY, Xu J, Xue H, Feng X, Zhu YC, Xiong ZQ. CDKL5 deficiency in adult glutamatergic neurons alters synaptic activity and causes spontaneous seizures via TrkB signaling. Cell Rep 2023; 42:113202. [PMID: 37777961 DOI: 10.1016/j.celrep.2023.113202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/26/2023] [Accepted: 09/16/2023] [Indexed: 10/03/2023] Open
Abstract
CDKL5 deficiency disorder (CDD) is a severe epileptic encephalopathy resulting from pathological mutations in the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene. Despite significant progress in understanding the neuronal function of CDKL5, the molecular mechanisms underlying CDD-associated epileptogenesis are unknown. Here, we report that acute ablation of CDKL5 from adult forebrain glutamatergic neurons leads to elevated neural network activity in the dentate gyrus and the occurrence of early-onset spontaneous seizures via tropomyosin-related kinase B (TrkB) signaling. We observe increased expression of brain-derived neurotrophic factor (BDNF) and enhanced activation of its receptor TrkB in the hippocampus of Cdkl5-deficient mice prior to the onset of behavioral seizures. Moreover, reducing TrkB signaling in these mice rescues the altered synaptic activity and suppresses recurrent seizures. These results suggest that TrkB signaling mediates epileptogenesis in a mouse model of CDD and that targeting this pathway might be effective for treating epilepsy in patients affected by CDKL5 mutations.
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Affiliation(s)
- Zi-Ai Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi-Yan Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Juan Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China
| | - Hui Xue
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xue Feng
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China
| | - Yong-Chuan Zhu
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China.
| | - Zhi-Qi Xiong
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 201210, China; School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
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Mrad Y, El Jammal R, Hajjar H, Alturk S, Salah H, Chehade HD, Dandash F, Mallah Z, Kobeissy F, Habib A, Hamade E, Obeid M. Lestaurtinib (CEP-701) reduces the duration of limbic status epilepticus in periadolescent rats. Epilepsy Res 2023; 195:107198. [PMID: 37467703 DOI: 10.1016/j.eplepsyres.2023.107198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 06/30/2023] [Accepted: 07/11/2023] [Indexed: 07/21/2023]
Abstract
BACKGROUND The timely abortion of status epilepticus (SE) is essential to avoid brain damage and long-term neurodevelopmental sequalae. However, available anti-seizure treatments fail to abort SE in 30% of children. Given the role of the tropomyosin-related kinase B (TrkB) receptor in hyperexcitability, we investigated if TrkB blockade with lestaurtinib (CEP-701) enhances the response of SE to a standard treatment protocol and reduces SE-related brain injury. METHODS SE was induced with intra-amygdalar kainic acid in postnatal day 45 rats under continuous electroencephalogram (EEG). Fifteen min post-SE onset, rats received intraperitoneal (i.p.) CEP-701 (KCEP group) or its vehicle (KV group). Controls received CEP-701 or its vehicle following intra-amygdalar saline. All groups received two i.p. doses of diazepam, followed by i.p. levetiracetam at 15 min intervals post-SE onset. Hippocampal TrkB dimer to monomer ratios were assessed by immunoblot 24 hr post-SE, along with neuronal densities and glial fibrillary acid protein (GFAP) levels. RESULTS SE duration was 50% shorter in the KCEP group compared to KV (p < 0.05). Compared to controls, SE induced a 1.5-fold increase in TrkB dimerization in KV rats (p < 0.05), but not in KCEP rats which were comparable to controls (p > 0.05). The KCEP group had lower GFAP levels than KV (p < 0.05), and both were higher than controls (p < 0.05). KCEP and KV rats had comparable hippocampal neuronal densities (p > 0.05), and both were lower than controls (p < 0.05). CONCLUSIONS Given its established human safety, CEP-701 is a promising adjuvant drug for the timely abortion of SE and the attenuation of SE-related brain injury.
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Affiliation(s)
- Yara Mrad
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Reem El Jammal
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon; Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Helene Hajjar
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Sana Alturk
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Houssein Salah
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Hiba-Douja Chehade
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon; Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI, USA
| | - Fatima Dandash
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Zahraa Mallah
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon; Laboratory of Cancer Biology and Molecular Immunology, Faculty of Sciences, Lebanese University, Hadath, Beirut, Lebanon
| | - Firas Kobeissy
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon; Center for Neurotrauma, Multiomics & Biomarkers (CNMB), Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia, USA
| | - Aida Habib
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Eva Hamade
- Laboratory of Cancer Biology and Molecular Immunology, Faculty of Sciences, Lebanese University, Hadath, Beirut, Lebanon
| | - Makram Obeid
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon; Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA; Division of Child Neurology, Department of Neurology, Indiana University School of Medicine, Riley Hospital for Children, Indianapolis, IN, USA.
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Kinboshi M, Shimizu S, Tokudome K, Mashimo T, Serikawa T, Ito H, Takahashi R, Ikeda A, Ohno Y. Imbalance of glutamatergic and GABAergic neurotransmission in audiogenic seizure-susceptible L eucine-rich glioma-inactivated 1 ( Lgi1)-mutant rats. Heliyon 2023; 9:e17984. [PMID: 37539249 PMCID: PMC10395352 DOI: 10.1016/j.heliyon.2023.e17984] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 06/26/2023] [Accepted: 07/04/2023] [Indexed: 08/05/2023] Open
Abstract
Leucine-rich glioma-inactivated 1 (LGI1) was identified as a causative gene of autosomal dominant lateral temporal lobe epilepsy. We previously reported that Lgi1-mutant rats carrying a missense mutation (L385R) showed audiogenic seizure-susceptibility. To explore the pathophysiological mechanisms underlying Lgi1-related epilepsy, we evaluated changes in glutamate and GABA release in Lgi1-mutant rats. Acoustic priming (AP) for audiogenic seizure-susceptibility was performed by applying intense sound stimulation (130 dB, 10 kHz, 5 min) on postnatal day 16. Extracellular glutamate and GABA levels in the hippocampus CA1 region were evaluated at 8 weeks of age, using in vivo microdialysis techniques. Under naïve conditions without AP, glutamate and GABA release evoked by high-K+ depolarization was more prominent in Lgi1-mutant than in wild-type (WT) rats. The AP treatment on day 16 significantly increased basal glutamate levels and depolarization-induced glutamate release both in Lgi1-mutant and WT rats, yielding greater depolarization-induced glutamate release in Lgi1-mutant rats. On the other hand, the AP treatment enhanced depolarization-induced GABA release only in WT rats, and not in Lgi1-mutant rats, illustrating reduced GABAergic neurotransmission in primed Lgi1-mutant rats. The present results suggest that enhanced glutamatergic and reduced GABAergic neurotransmission are involved in the audiogenic seizure-susceptibility associated with Lgi1-mutation.
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Affiliation(s)
- Masato Kinboshi
- Department of Pharmacology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, 569-1094, Japan
- Department of Neurology, Wakayama Medical University, Wakayama, 641-8509, Japan
- Department of Neurology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Saki Shimizu
- Department of Pharmacology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, 569-1094, Japan
| | - Kentaro Tokudome
- Department of Pharmacology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, 569-1094, Japan
| | - Tomoji Mashimo
- Laboratory Animal Research Center, Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, 108-8639, Japan
| | - Tadao Serikawa
- Department of Pharmacology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, 569-1094, Japan
| | - Hidefumi Ito
- Department of Neurology, Wakayama Medical University, Wakayama, 641-8509, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Yukihiro Ohno
- Department of Pharmacology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, Takatsuki, Osaka, 569-1094, Japan
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Mantilla CB, Ermilov LG, Greising SM, Gransee HM, Zhan WZ, Sieck GC. Electrophysiological effects of BDNF and TrkB signaling at type-identified diaphragm neuromuscular junctions. J Neurophysiol 2023; 129:781-792. [PMID: 36883761 PMCID: PMC10069962 DOI: 10.1152/jn.00015.2023] [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: 01/13/2023] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/09/2023] Open
Abstract
Previous studies show that synaptic quantal release decreases during repetitive stimulation, i.e., synaptic depression. Neurotrophin brain-derived neurotrophic factor (BDNF) enhances neuromuscular transmission via activation of tropomyosin-related kinase receptor B (TrkB). We hypothesized that BDNF mitigates synaptic depression at the neuromuscular junction and that the effect is more pronounced at type IIx and/or IIb fibers compared to type I or IIa fibers given the more rapid reduction in docked synaptic vesicles with repetitive stimulation. Rat phrenic nerve-diaphragm muscle preparations were used to determine the effect of BDNF on synaptic quantal release during repetitive stimulation at 50 Hz. An ∼40% decline in quantal release was observed during each 330-ms duration train of nerve stimulation (intratrain synaptic depression), and this intratrain decline was observed across repetitive trains (20 trains at 1/s repeated every 5 min for 30 min for 6 sets). BDNF treatment significantly enhanced quantal release at all fiber types (P < 0.001). BDNF treatment did not change release probability within a stimulation set but enhanced synaptic vesicle replenishment between sets. In agreement, synaptic vesicle cycling (measured using FM4-64 fluorescence uptake) was increased following BDNF [or neurotrophin-4 (NT-4)] treatment (∼40%; P < 0.05). Conversely, inhibiting BDNF/TrkB signaling with the tyrosine kinase inhibitor K252a and TrkB-IgG (which quenches endogenous BDNF or NT-4) decreased FM4-64 uptake (∼34% across fiber types; P < 0.05). The effects of BDNF were generally similar across all fiber types. We conclude that BDNF/TrkB signaling acutely enhances presynaptic quantal release and thereby may serve to mitigate synaptic depression and maintain neuromuscular transmission during repetitive activation.NEW & NOTEWORTHY Neurotrophin brain-derived neurotrophic factor (BDNF) enhances neuromuscular transmission via activation of tropomyosin-related kinase receptor B (TrkB). Rat phrenic nerve-diaphragm muscle preparations were used to determine the rapid effect of BDNF on synaptic quantal release during repetitive stimulation. BDNF treatment significantly enhanced quantal release at all fiber types. BDNF increased synaptic vesicle cycling (measured using FM4-64 fluorescence uptake); conversely, inhibiting BDNF/TrkB signaling decreased FM4-64 uptake.
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Affiliation(s)
- Carlos B Mantilla
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Leonid G Ermilov
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Sarah M Greising
- School of Kinesiology, University of Minnesota, Minneapolis, Minnesota, United States
| | - Heather M Gransee
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Wen-Zhi Zhan
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Gary C Sieck
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
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Guarino A, Bettegazzi B, Aziz N, Barbieri M, Bochicchio D, Crippa L, Marino P, Sguizzato M, Soukupova M, Zucchini S, Simonato M. Low-dose 7,8-Dihydroxyflavone Administration After Status Epilepticus Prevents Epilepsy Development. Neurotherapeutics 2022; 19:1951-1965. [PMID: 36180719 PMCID: PMC9723075 DOI: 10.1007/s13311-022-01299-4] [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] [Accepted: 09/08/2022] [Indexed: 12/14/2022] Open
Abstract
Temporal lobe epilepsy often manifests months or even years after an initial epileptogenic insult (e.g., stroke, trauma, status epilepticus) and, therefore, may be preventable. However, no such preventive treatment is currently available. Aim of this study was to test an antioxidant agent, 7,8-dihydroxyflavone (7,8-DHF), that is well tolerated and effective in preclinical models of many neurological disorders, as an anti-epileptogenic drug. However, 7,8-DHF also acts as a TrkB receptor agonist and, based on the literature, this effect may imply an anti- or a pro-epileptogenic effect. We found that low- (5 mg/kg), but not high-dose 7,8-DHF (10 mg/kg) can exert strong anti-epileptogenic effects in the lithium-pilocarpine model (i.e., highly significant reduction in the frequency of spontaneous seizures and in the time to first seizure after status epilepticus). The mechanism of these different dose-related effects remains to be elucidated. Nonetheless, considering its excellent safety profile and antioxidant properties, as well as its putative effects on TrkB receptors, 7,8-DHF represents an interesting template for the development of effective and well-tolerated anti-epileptogenic drugs.
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Affiliation(s)
- Annunziata Guarino
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121, Ferrara, Italy
| | - Barbara Bettegazzi
- University Vita-Salute San Raffaele, via Olgettina 58, 20132, Milan, Italy
| | - Nimra Aziz
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121, Ferrara, Italy
| | - Mario Barbieri
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121, Ferrara, Italy
| | - Daniela Bochicchio
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121, Ferrara, Italy
| | - Lucia Crippa
- University Vita-Salute San Raffaele, via Olgettina 58, 20132, Milan, Italy
| | - Pietro Marino
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121, Ferrara, Italy
| | - Maddalena Sguizzato
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121, Ferrara, Italy
| | - Marie Soukupova
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121, Ferrara, Italy
| | - Silvia Zucchini
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121, Ferrara, Italy.
- Laboratory of Technologies for Advanced Therapy (LTTA), Technopole of Ferrara, Ferrara, Italy.
| | - Michele Simonato
- Department of Neuroscience and Rehabilitation, University of Ferrara, via Fossato di Mortara 70, 44121, Ferrara, Italy
- Division of Neuroscience, IRCCS San Raffaele Hospital, via Olgettina 60, 20132, Milan, Italy
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Patel DC, Thompson EG, Sontheimer H. Brain-Derived Neurotrophic Factor Inhibits the Function of Cation-Chloride Cotransporter in a Mouse Model of Viral Infection-Induced Epilepsy. Front Cell Dev Biol 2022; 10:961292. [PMID: 35874836 PMCID: PMC9304572 DOI: 10.3389/fcell.2022.961292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 06/20/2022] [Indexed: 11/15/2022] Open
Abstract
Well over 100 different viruses can infect the brain and cause brain inflammation. In the developing world, brain inflammation is a leading cause for epilepsy and often refractory to established anti-seizure drugs. Epilepsy generally results from an imbalance in excitatory glutamatergic and inhibitory GABAergic neurotransmission. GABAergic inhibition is determined by the intracellular Cl− concentration which is established through the opposing action of two cation chloride cotransporters namely NKCC1 and KCC2. Brain-derived neurotrophic factor (BDNF) signaling is known to regulate expression of KCC2. Hence we hypothesized that viral induced epilepsy may result from aberrant BDNF signaling. We tested this hypothesis using a mouse model of Theiler’s murine encephalomyelitis virus (TMEV) infection-induced epilepsy. We found that BDNF levels in the hippocampus from TMEV-infected mice with seizures was increased at the onset of acute seizures and continued to increase during the peak of acute seizure as well as in latent and chronic phases of epilepsy. During the acute phase of epilepsy, we found significant reduction in the expression of KCC2 in hippocampus, whereas the level of NKCC1 was unaltered. Importantly, inhibiting BDNF using scavenging bodies of BDNF in live brain slices from TMEV-infected mice with seizures normalized the level of KCC2 in hippocampus. Our results suggest that BDNF can directly decrease the relative expression of NKCC1 and KCC2 such as to favor accumulation of chloride intracellularly which in turn causes hyperexcitability by reversing GABA-mediated inhibition. Although our attempt to inhibit the BDNF signaling mediated through tyrosine kinase B–phospholipase Cγ1 (TrkB-PLCγ1) using a small peptide did not change the course of seizure development following TMEV infection, alternative strategies for controlling the BDNF signaling could be useful in preventing seizure generation and development of epilepsy in this model.
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Affiliation(s)
- Dipan C. Patel
- Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute at Virginia Tech-Carilion, Roanoke, VA, United States
| | - Emily G. Thompson
- Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute at Virginia Tech-Carilion, Roanoke, VA, United States
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Harald Sontheimer
- Glial Biology in Health, Disease, and Cancer Center, Fralin Biomedical Research Institute at Virginia Tech-Carilion, Roanoke, VA, United States
- School of Neuroscience, Virginia Tech, Blacksburg, VA, United States
- *Correspondence: Harald Sontheimer,
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Aygun H, Akin AT, Kızılaslan N, Sumbul O, Karabulut D. Probiotic supplementation alleviates absence seizures and anxiety- and depression-like behavior in WAG/Rij rat by increasing neurotrophic factors and decreasing proinflammatory cytokines. Epilepsy Behav 2022; 128:108588. [PMID: 35152169 DOI: 10.1016/j.yebeh.2022.108588] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 01/22/2022] [Accepted: 01/22/2022] [Indexed: 01/15/2023]
Abstract
AIM Epilepsy is one of the most common chronic brain disorders that affect millions of people worldwide. In the present study, we investigated the effects of probiotic supplementation on absence epilepsy and anxiety-and depression-like behavior in WAG/Rij rats. MATERIAL AND METHOD Fourteen male WAG/Rij rats (absence-epileptic) and seven male Wistar rats (nonepileptic) were used. The effects of probiotic VSL#3 (12.86 bn living bacteria/kg/day for 30 day/gavage) on absence seizures, and related psychiatric comorbidities were evaluated in WAG/Rij rats. Anxiety-like behavior was evaluated by the open-field test and depression-like behavior by the forced swimming test. In addition, the brain tissues of rats were evaluated histopathologically for nerve growth factor [NGF], brain-derived neurotrophic factor [BDNF], SRY sex-determining region Y-box 2 [SOX2] and biochemically for nitric oxide [NO], tumor necrosis factor-alpha [TNF-α] ,and Interleukin-6 [IL-6]. RESULTS Compared to Wistar rats, WAG/Rij rats exhibited anxiety- and depression-like behavior, and had lower BDNF, NGF and SOX2 immunoreactivity, and higher TNF-α, IL-6 levels in brain tissue. VSL#3 supplementation reduced the duration and number of spike-wave discharges (SWDs) and exhibited anxiolytic or anti-depressive effect. VSL#3 supplement also increased the NGF immunoreactivity while decreasing IL-6, TNF-α and NO levels in WAG/Rij rat brain. CONCLUSION The findings of the present study showed that neurotrophins, SOX2 deficiency, and pro-inflammatory cytokines may play a role in the pathogenesis of absence epilepsy. Our data support the hypothesis that the probiotics have anti-inflammatory effect. The present study is the first to show the positive effects of probiotic bacteria on absence seizures and anxiety- and depression-like behavior.
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Affiliation(s)
- Hatice Aygun
- Department of Physiology, Faculty of Medicine, University of Tokat Gaziosmanpasa, Tokat, Turkey.
| | - Ali Tugrul Akin
- Department of Biology, Faculty of Science and Literature, University of Erciyes, Kayseri, Turkey
| | - Nildem Kızılaslan
- Department of Nutrition and Dietetics, Faculty of Health Sciences, University of Tokat Gaziosmanpasa Tokat, Turkey
| | - Orhan Sumbul
- Department of Neurology Faculty of Medicine University of Tokat Gaziosmanpasa, Tokat, Turkey
| | - Derya Karabulut
- Department of Histology-Embryology, Faculty of Medicine, University of Erciyes, Kayseri, Turkey
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Butler-Ryan R, Wood IC. The functions of repressor element 1-silencing transcription factor in models of epileptogenesis and post-ischemia. Metab Brain Dis 2021; 36:1135-1150. [PMID: 33813634 PMCID: PMC8272694 DOI: 10.1007/s11011-021-00719-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/17/2021] [Indexed: 12/14/2022]
Abstract
Epilepsy is a debilitating neurological disorder characterised by recurrent seizures for which 30% of patients are refractory to current treatments. The genetic and molecular aetiologies behind epilepsy are under investigation with the goal of developing new epilepsy medications. The transcriptional repressor REST (Repressor Element 1-Silencing Transcription factor) is a focus of interest as it is consistently upregulated in epilepsy patients and following brain insult in animal models of epilepsy and ischemia. This review analyses data from different epilepsy models and discusses the contribution of REST to epileptogenesis. We propose that in healthy brains REST acts in a protective manner to homeostatically downregulate increases in excitability, to protect against seizure through downregulation of BDNF (Brain-Derived Neurotrophic Factor) and its receptor, TrkB (Tropomyosin receptor kinase B). However, in epilepsy patients and post-seizure, REST may increase to a larger degree, which allows downregulation of the glutamate receptor subunit GluR2. This leads to AMPA glutamate receptors lacking GluR2 subunits, which have increased permeability to Ca2+, causing excitotoxicity, cell death and seizure. This concept highlights therapeutic potential of REST modulation through gene therapy in epilepsy patients.
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Affiliation(s)
- Ruth Butler-Ryan
- School of Biomedical Sciences, Faculty of Biological Sciences, The University of Leeds, Leeds, LS2 9JT UK
| | - Ian C. Wood
- School of Biomedical Sciences, Faculty of Biological Sciences, The University of Leeds, Leeds, LS2 9JT UK
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Abstract
Brain-derived neurotrophic factor (BDNF) and the high-affinity receptor tropomyosin receptor kinase B (TrkB) have important roles in neuronal survival and in spinal sensitization mechanisms associated with chronic pain. Recent clinical evidence also supports a peripheral role of BDNF in osteoarthritis (OA), with synovial expression of TrkB associated with higher OA pain. The aim of this study was to use clinical samples and animal models to explore the potential contribution of knee joint BDNF/TrkB signalling to chronic OA pain. Brain-derived neurotrophic factor and TrkB mRNA and protein were present in knee synovia from OA patients (16 women, 14 men, median age 67 years [interquartile range: 61-73]). There was a significant positive correlation between mRNA expression of NTRK2 (TrkB) and the proinflammatory chemokine fractalkine in the OA synovia. Using the surgical medial meniscal transection (MNX) model and the chemical monosodium iodoacetate (MIA) model of OA pain in male rats, the effects of peripheral BDNF injection, vs sequestering endogenous BDNF with TrkB-Fc chimera, on established pain behaviour were determined. Intra-articular injection of BDNF augmented established OA pain behaviour in MIA rats, but had no effect in controls. Intra-articular injection of the TrkB-Fc chimera acutely reversed pain behaviour to a similar extent in both models of OA pain (weight-bearing asymmetry MIA: -11 ± 4%, MNX: -12 ± 4%), compared to vehicle treatment. Our data suggesting a contribution of peripheral knee joint BDNF/TrkB signalling in the maintenance of chronic OA joint pain support further investigation of the therapeutic potential of this target.
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10
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Kinboshi M, Ikeda A, Ohno Y. Role of Astrocytic Inwardly Rectifying Potassium (Kir) 4.1 Channels in Epileptogenesis. Front Neurol 2020; 11:626658. [PMID: 33424762 PMCID: PMC7786246 DOI: 10.3389/fneur.2020.626658] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/08/2020] [Indexed: 12/25/2022] Open
Abstract
Astrocytes regulate potassium and glutamate homeostasis via inwardly rectifying potassium (Kir) 4.1 channels in synapses, maintaining normal neural excitability. Numerous studies have shown that dysfunction of astrocytic Kir4.1 channels is involved in epileptogenesis in humans and animal models of epilepsy. Specifically, Kir4.1 channel inhibition by KCNJ10 gene mutation or expressional down-regulation increases the extracellular levels of potassium ions and glutamate in synapses and causes hyperexcitation of neurons. Moreover, recent investigations demonstrated that inhibition of Kir4.1 channels facilitates the expression of brain-derived neurotrophic factor (BDNF), an important modulator of epileptogenesis, in astrocytes. In this review, we summarize the current understanding on the role of astrocytic Kir4.1 channels in epileptogenesis, with a focus on functional and expressional changes in Kir4.1 channels and their regulation of BDNF secretion. We also discuss the potential of Kir4.1 channels as a therapeutic target for the prevention of epilepsy.
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Affiliation(s)
- Masato Kinboshi
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan.,Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yukihiro Ohno
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
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11
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Insights into Potential Targets for Therapeutic Intervention in Epilepsy. Int J Mol Sci 2020; 21:ijms21228573. [PMID: 33202963 PMCID: PMC7697405 DOI: 10.3390/ijms21228573] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/04/2020] [Accepted: 11/11/2020] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a chronic brain disease that affects approximately 65 million people worldwide. However, despite the continuous development of antiepileptic drugs, over 30% patients with epilepsy progress to drug-resistant epilepsy. For this reason, it is a high priority objective in preclinical research to find novel therapeutic targets and to develop effective drugs that prevent or reverse the molecular mechanisms underlying epilepsy progression. Among these potential therapeutic targets, we highlight currently available information involving signaling pathways (Wnt/β-catenin, Mammalian Target of Rapamycin (mTOR) signaling and zinc signaling), enzymes (carbonic anhydrase), proteins (erythropoietin, copine 6 and complement system), channels (Transient Receptor Potential Vanilloid Type 1 (TRPV1) channel) and receptors (galanin and melatonin receptors). All of them have demonstrated a certain degree of efficacy not only in controlling seizures but also in displaying neuroprotective activity and in modifying the progression of epilepsy. Although some research with these specific targets has been done in relation with epilepsy, they have not been fully explored as potential therapeutic targets that could help address the unsolved issue of drug-resistant epilepsy and develop new antiseizure therapies for the treatment of epilepsy.
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12
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Yu Y, Jiang J. COX-2/PGE 2 axis regulates hippocampal BDNF/TrkB signaling via EP2 receptor after prolonged seizures. Epilepsia Open 2020; 5:418-431. [PMID: 32913950 PMCID: PMC7469770 DOI: 10.1002/epi4.12409] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 04/22/2020] [Accepted: 05/14/2020] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE The objective of this study was to identify the signaling pathway that is immediately triggered by status epilepticus (SE) and in turn contributes to the excessive brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase receptor B (TrkB) signaling within the hippocampus. METHODS We used quantitative PCR, enzyme-linked immunosorbent assay, and Western blot analysis to examine gene expression at both mRNA and protein levels in the hippocampus following prolonged SE in mice and rats. Three classical animal models of SE were utilized in the present study to avoid any model- or species-specific findings. RESULTS We showed that both cyclooxygenase-2 (COX-2) and BDNF in the hippocampus were rapidly upregulated after SE onset; however, the induction of COX-2 temporally preceded that of BDNF. Blocking COX-2 activity by selective inhibitor SC-58125 prevented BDNF elevation in the hippocampus following SE; prostaglandin E2 (PGE2), a major product of COX-2 in the brain, was sufficient to stimulate hippocampal cells to secrete BDNF, suggesting that a PGE2 signaling pathway might be directly involved in hippocampal BDNF production. Inhibiting the Gαs-coupled PGE2 receptor EP2 by our recently developed selective antagonist TG6-10-1 decreased the SE-triggered phosphorylation of the cAMP response element-binding protein (CREB) and activation of the BDNF/TrkB signaling in the hippocampus. SIGNIFICANCE The molecular mechanisms whereby BDNF/TrkB signaling is upregulated in the hippocampus by SE largely remain unknown. Our findings suggest that COX-2 via the PGE2/EP2 pathway regulates hippocampal BDNF/TrkB activity following prolonged seizures. EP2 inhibition by our bioavailable and brain-permeable antagonists such as TG6-10-1 might therefore provide a novel strategy to suppress the abnormal TrkB activity, an event that can sufficiently trigger pathogenic processes within the brain including acquired epileptogenesis.
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Affiliation(s)
- Ying Yu
- Department of Pharmaceutical SciencesCollege of PharmacyUniversity of Tennessee Health Science CenterMemphisTNUSA
| | - Jianxiong Jiang
- Department of Pharmaceutical SciencesCollege of PharmacyUniversity of Tennessee Health Science CenterMemphisTNUSA
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13
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Chmielewska N, Wawer A, Maciejak P, Turzyńska D, Sobolewska A, Skórzewska A, Osuch B, Płaźnik A, Szyndler J. The role of REST/NRSF, TrkB and BDNF in neurobiological mechanisms of different susceptibility to seizure in a PTZ model of epilepsy. Brain Res Bull 2020; 158:108-115. [PMID: 32151715 DOI: 10.1016/j.brainresbull.2020.03.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/24/2020] [Accepted: 03/05/2020] [Indexed: 01/05/2023]
Abstract
Global transcriptional disturbances are believed to play a major role in the course of epilepsy. Due to the high complexity, the neurobiological mechanisms underlying different susceptibility to seizure and epilepsy are not well known. A transcription factor called REST/NRSF (repressor element 1-silencing transcription factor/neuron-restrictive silencer factor) is believed to contribute to processes associated with seizure development. Its downstream genes, those encoding BDNF (brain-derived neurotrophic factor) and TrkB (BDNF receptor; tropomyosin receptor kinase B), are also thought to play a role. To verify this hypothesis, we used a PTZ kindling model of epilepsy and divided animals into groups according to their different susceptibility to seizure. The concentrations of REST/NRSF, BDNF, and TrkB protein and mRNA were measured in hippocampal homogenates. The level of REST/NRSF protein measured 24 h after the last PTZ injection was increased in animals resistant to kindling and was unchanged in groups of rats kindled after 5, 10 and 20 in.ections of PTZ. In contrast, TrkB protein concentration was enhanced in all kindled rats and was unchanged in the resistant rats. There were no changes in the protein concentration of BDNF in rats with different susceptibility to kindling; however, data from the combined kindled groups vs. the resistant group revealed an increased level of BDNF in resistant animals. In sum, the increased level of protein REST/NRSF in resistant animals may reflect its neuroprotective role against seizure development. The increased concentration of TrkB protein in kindled animals indicates its pivotal role in the process of epileptogenesis. We propose that in resistant rats, REST/NRSF could contribute to the prevention of TrkB activation related to seizures.
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Affiliation(s)
- Natalia Chmielewska
- Department of Neurochemistry, Institute of Psychiatry and Neurology, Sobieskiego Street 9, 02-957, Warsaw, Poland.
| | - Adriana Wawer
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology CePT, Medical University of Warsaw, Banacha 1B, 02-097, Warsaw, Poland.
| | - Piotr Maciejak
- Department of Neurochemistry, Institute of Psychiatry and Neurology, Sobieskiego Street 9, 02-957, Warsaw, Poland; Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology CePT, Medical University of Warsaw, Banacha 1B, 02-097, Warsaw, Poland.
| | - Danuta Turzyńska
- Department of Neurochemistry, Institute of Psychiatry and Neurology, Sobieskiego Street 9, 02-957, Warsaw, Poland.
| | - Alicja Sobolewska
- Department of Neurochemistry, Institute of Psychiatry and Neurology, Sobieskiego Street 9, 02-957, Warsaw, Poland.
| | - Anna Skórzewska
- Department of Neurochemistry, Institute of Psychiatry and Neurology, Sobieskiego Street 9, 02-957, Warsaw, Poland.
| | - Bartosz Osuch
- Department of Neurochemistry, Institute of Psychiatry and Neurology, Sobieskiego Street 9, 02-957, Warsaw, Poland.
| | - Adam Płaźnik
- Department of Neurochemistry, Institute of Psychiatry and Neurology, Sobieskiego Street 9, 02-957, Warsaw, Poland.
| | - Janusz Szyndler
- Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology CePT, Medical University of Warsaw, Banacha 1B, 02-097, Warsaw, Poland.
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14
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Zhu L, Chen L, Xu P, Lu D, Dai S, Zhong L, Han Y, Zhang M, Xiao B, Chang L, Wu Q. Genetic and molecular basis of epilepsy-related cognitive dysfunction. Epilepsy Behav 2020; 104:106848. [PMID: 32028124 DOI: 10.1016/j.yebeh.2019.106848] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 12/06/2019] [Accepted: 12/06/2019] [Indexed: 02/02/2023]
Abstract
Epilepsy is a common neurological disease characterized by recurrent seizures. About 70 million people were affected by epilepsy or epileptic seizures. Epilepsy is a complicated complex or symptomatic syndromes induced by structural, functional, and genetic causes. Meanwhile, several comorbidities are accompanied by epileptic seizures. Cognitive dysfunction is a long-standing complication associated with epileptic seizures, which severely impairs quality of life. Although the definitive pathogenic mechanisms underlying epilepsy-related cognitive dysfunction remain unclear, accumulating evidence indicates that multiple risk factors are probably involved in the development and progression of cognitive dysfunction in patients with epilepsy. These factors include the underlying etiology, recurrent seizures or status epilepticus, structural damage that induced secondary epilepsy, genetic variants, and molecular alterations. In this review, we summarize several theories that may explain the genetic and molecular basis of epilepsy-related cognitive dysfunction.
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Affiliation(s)
- Lin Zhu
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Lu Chen
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Puying Xu
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Di Lu
- Biomedicine Engineering Research Center, Kunming Medical University, 1168 Chun Rong West Road, Kunming, Yunnan 650500, PR China
| | - Shujuan Dai
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Lianmei Zhong
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Yanbing Han
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China
| | - Mengqi Zhang
- Department of Neurology, Xiangya Hospital, Central South University, 87 Xiang Ya Road, Changsha, Hunan 410008, PR China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, 87 Xiang Ya Road, Changsha, Hunan 410008, PR China
| | - Lvhua Chang
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China.
| | - Qian Wu
- Department of Neurology, First Affiliated Hospital, Kunming Medical University, 295 Xi Chang Road, Kunming, Yunnan 650032, PR China.
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15
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Kotloski RJ, Rutecki PA, Sutula TP. Genetic Background Influences Acute Response to TBI in Kindling-Susceptible, Kindling-Resistant, and Outbred Rats. Front Neurol 2020; 10:1286. [PMID: 31998207 PMCID: PMC6968787 DOI: 10.3389/fneur.2019.01286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 11/20/2019] [Indexed: 01/13/2023] Open
Abstract
We hypothesized that the acute response to traumatic brain injury (TBI) shares mechanisms with brain plasticity in the kindling model. Utilizing two unique, complementary strains of inbred rats, selected to be either susceptible or resistant to seizure-induced plasticity evoked by kindling of the perforant path, we examined acute electrophysiological alterations and differences in brain-derived neurotrophic factor (BDNF) protein concentrations after a moderate-to-severe brain injury. At baseline, limited strain-dependent differences in acute electrophysiological activity were found, and no differences in BDNF. Following injury, pronounced strain-dependent differences in electrophysiologic activity were noted at 0.5 min. However, the divergence is transient, with diminished differences at 5 min after injury and no differences at 10 and 15 min after injury. Strain-specific differences in BDNF protein concentration were noted 4 h after injury. A simple risk score model generated by machine learning and based solely on post-injury electrophysiologic activity at the 0.5-min timepoint distinguished perforant path kindling susceptible (PPKS) rats from non-plasticity-susceptible strains. The findings demonstrate that genetic background which affects brain circuit plasticity also affects acute response to TBI. An improved understanding of the effect of genetic background on the cellular, molecular, and circuit plasticity mechanisms activated in response to TBI and their timecourse is key in developing much-needed novel therapeutic approaches.
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Affiliation(s)
- Robert J Kotloski
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States.,Department of Neurology, William S. Middleton Memorial Veterans Hospital, Madison, WI, United States
| | - Paul A Rutecki
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States.,Department of Neurology, William S. Middleton Memorial Veterans Hospital, Madison, WI, United States
| | - Thomas P Sutula
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
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16
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Göl MF, Erdoğan FF, Bayramov KK, Mehmetbeyoğlu E, Özkul Y. Assessment of genes involved in behavior, learning, memory, and synaptic plasticity following status epilepticus in rats. Epilepsy Behav 2019; 98:101-109. [PMID: 31326869 DOI: 10.1016/j.yebeh.2019.06.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/09/2019] [Accepted: 06/11/2019] [Indexed: 02/05/2023]
Abstract
OBJECTIVE In this study, it was aimed to evaluate cognitive and behavioral changes after status epilepticus (SE) induced by pentylenetetrazole in immature rats via Morris water maze and open-field area tests and to assess alterations in expression of 84 key genes involved in synaptic plasticity after SE. METHOD The study was conducted on 30 immature rats (12-days old). The rats were assigned into groups as control and experiment (SE) groups. The SE was induced by pentylenetetrazole in 12-days old rats. In addition, experiment group was divided into two groups as mature (n = 8) and immature SE (n = 8) subgroups. Again, the control group was divided into two groups as mature (n = 7) and immature control (n = 7) subgroups. Hippocampal tissue samples were prepared, and expression of 84 key genes involved in synaptic plasticity was assessed in Genome and Stem Cell Center of Erciyes University before behavioral tests in immature rats (22-days old) and after open-filed area and Morris water maze tests in mature rats (72-days old) in both experiment and control groups. RESULTS No significant difference was detected in behavioral tests assessing spatial memory and learning among groups. Significant differences were detected, ARC (activity-regulated cytoskeleton-associated protein), BDNF (brain-derived neurotrophic factor), MAPK1 (mitogen-activated protein kinase 1), NR4A1 (nuclear receptor subfamily 4 group A member 1), PPP3CA (protein phosphatase 3 catalytic subunit alpha), RGS2 (regulator of G protein signaling 2), and TNF (tumor necrosis factor) gene expressions between control and experiment groups in immature rats whereas in ADCY8 (adenylate cyclase 8), BDNF (brain-derived neurotrophic factor), EGR4 (early growth response 4), and KIF17 (kinesin family member 17) gene expressions between control and experiment groups in mature rats. DISCUSSION In this study, differences detected in gene expressions of synaptic plasticity after SE indicate in which steps of synaptic plasticity may be problematic in epileptogenesis. The gene expressions in this study may be considered as potential biomarkers; however, epileptogenesis is a dynamic process and cannot be explained through a single mechanism. Future studies on epileptogenesis and studies specifically designed to evaluate genes detected in our study will further elucidate synaptic plasticity in epilepsy and epileptogenesis.
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Affiliation(s)
- Mehmet Fatih Göl
- Department of Neurology, Kayseri City Hospital, Kayseri, Turkey.
| | - Füsun Ferda Erdoğan
- Department of Neurology, Erciyes University Faculty of Medicine, Kayseri, Turkey
| | | | | | - Yusuf Özkul
- Department of Medical Genetics, Erciyes University Faculty of Medicine, Kayseri, Turkey
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17
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Down-Regulation of Astrocytic Kir4.1 Channels during the Audiogenic Epileptogenesis in Leucine-Rich Glioma-Inactivated 1 ( Lgi1) Mutant Rats. Int J Mol Sci 2019; 20:ijms20051013. [PMID: 30813600 PMCID: PMC6429235 DOI: 10.3390/ijms20051013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/14/2019] [Accepted: 02/21/2019] [Indexed: 02/07/2023] Open
Abstract
The dysfunction of astrocytic inwardly rectifying potassium (Kir) 4.1 channels, which mediate the spatial potassium-buffering function of astrocytes, is known to be involved in the development of epilepsy. Here, we analyzed the Kir4.1 expressional changes in Leucine-Rich Glioma-Inactivated 1 (Lgi1) mutant rats, which is a model of autosomal dominant lateral temporal lobe epilepsy in humans, to clarify the role of astrocytic Kir4.1 channels in Lgi1-related epileptogenesis. Priming acoustic stimulation (at postnatal day 16) conferred seizure susceptibility on Lgi1 mutant rats, which evoked audiogenic seizures with test stimulation at eight weeks. In the seizure-susceptible Lgi1 mutant rats (before test stimulation), astrocytic Kir4.1 expression was down-regulated region-specifically in the cerebral cortex, hippocampus, and amygdala. In addition, prophylactic treatments of Lgi1 mutant rats with valproic acid (VPA, 30 mg/kg and 200 mg/kg) for two weeks prevented both the development of seizure susceptibility and the down-regulation of Kir4.1 expression in astrocytes. The present study demonstrated for the first time that the astrocytic Kir4.1 expression was reduced in the Lgi1-related seizure model, suggesting that the down-regulation of Kir4.1 channels in astrocytes is involved in audiogenic epileptogenesis caused by Lgi1 mutation. In addition, VPA seemed to have a prophylactic effect on Lgi1-related seizures.
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18
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Montroull LE, Danelon V, Cragnolini AB, Mascó DH. Loss of TrkB Signaling Due to Status Epilepticus Induces a proBDNF-Dependent Cell Death. Front Cell Neurosci 2019; 13:4. [PMID: 30800056 PMCID: PMC6375841 DOI: 10.3389/fncel.2019.00004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 01/08/2019] [Indexed: 01/25/2023] Open
Abstract
Neurotrophins (NTs) are secretory proteins that bind to target receptors and influence many cellular functions, such as cell survival and cell death in neurons. The mammalian NT brain-derived neurotrophic factor (matBDNF) is the C-terminal mature form released by cleavage from the proBDNF precursor. The binding of matBDNF to the tyrosine kinase receptor B (TrkB) activates different signaling cascades and leads to neuron survival and plasticity, while the interaction of proBDNF with the p75 NT receptor (p75NTR)/sortilin receptor complex has been highly involved in apoptosis. Many studies have demonstrated that prolonged seizures such as status epilepticus (SE) induce changes in the expression of NT, pro-NT, and their receptors. We have previously described that the blockage of both matBDNF and proBDNF signaling reduces neuronal death after SE in vivo (Unsain et al., 2008). We used an in vitro model as well as an in vivo model of SE to determine the specific role of TrkB and proBDNF signaling during neuronal cell death. We found that the matBDNF sequestering molecule TrkB-Fc induced an increase in neuronal death in both models of SE, and it also prevented a decrease in TrkB levels. Moreover, SE triggered the interaction between proBDNF and p75NTR, which was not altered by sequestering matBDNF. The intra-hippocampal administration of TrkB-Fc, combined with an antibody against proBDNF, prevented neuronal degeneration. In addition, we demonstrated that proBDNF binding to p75NTR exacerbates neuronal death when matBDNF signaling is impaired through TrkB. Our results indicated that both the mature and the precursor forms of BDNF may have opposite effects depending on the scenario in which they function and the signaling pathways they activate.
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Affiliation(s)
- Laura Ester Montroull
- Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba; Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Víctor Danelon
- Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba; Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andrea Beatriz Cragnolini
- Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba; Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Daniel Hugo Mascó
- Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba; Instituto de Investigaciones Biológicas y Tecnológicas (IIByT), CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
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19
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Iughetti L, Lucaccioni L, Fugetto F, Predieri B, Berardi A, Ferrari F. Brain-derived neurotrophic factor and epilepsy: a systematic review. Neuropeptides 2018; 72:23-29. [PMID: 30262417 DOI: 10.1016/j.npep.2018.09.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 08/13/2018] [Accepted: 09/19/2018] [Indexed: 12/09/2022]
Abstract
Several in vitro, ex vivo and in vivo studies imply brain-derived neurotrophic factor (BDNF) in the pathophysiology of epilepsy. Aim of our work is to report the most important findings regarding BDNF and its potential role in epilepsy. We targeted those publications addressing both in vitro and in vivo evidences of relationship between BDNF and epilepsy. Basic researches, randomized trials, cohort studies, and reviews were contemplated to give a breadth of clinical data. Medline, CENTRAL, and Science Direct were searched till August 2017 using keywords agreed by the authors. Together with a defined role in developmental and mature brain, BDNF has excitatory effects in neuronal cultures and animal brain slices. Furthermore, both BDNF and its conjugated receptor (i.e. Tropomyosin receptor kinase B or TrkB) are increased in animal models and humans with epilepsy, particularly in the temporal and hippocampal areas. Acute injection of BDNF in brain of mice induces seizures, which are almost or totally abolished blocking its transcription and pathway. Chronic infusion of BDNF is conversely associated with a decreased neuronal excitability, probably via several mechanism including an increase in central levels of neuropeptide Y (NPY), altered conductance of chloride, and downregulation of TrkB. While genetic studies are inconclusive, serum BDNF is more frequently higher in patients with epilepsy and appears to be correlated to severity of disease. Current evidences suggest that inhibiting BDNF-TrkB signaling and reinforcing the NPY system could represent a potential therapeutic strategy for epilepsy, especially for temporal lobe epilepsy.
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Affiliation(s)
- Lorenzo Iughetti
- Department of Medical and Surgical Sciences of the Mother, Children and Adults. University of Modena and Reggio Emilia, Via del Pozzo n. 71, 41124 Modena, Italy.
| | - Laura Lucaccioni
- Department of Medical and Surgical Sciences of the Mother, Children and Adults. University of Modena and Reggio Emilia, Via del Pozzo n. 71, 41124 Modena, Italy
| | - Francesco Fugetto
- Department of Medical and Surgical Sciences of the Mother, Children and Adults. University of Modena and Reggio Emilia, Via del Pozzo n. 71, 41124 Modena, Italy
| | - Barbara Predieri
- Department of Medical and Surgical Sciences of the Mother, Children and Adults. University of Modena and Reggio Emilia, Via del Pozzo n. 71, 41124 Modena, Italy
| | - Alberto Berardi
- Department of Medical and Surgical Sciences of the Mother, Children and Adults. University of Modena and Reggio Emilia, Via del Pozzo n. 71, 41124 Modena, Italy
| | - Fabrizio Ferrari
- Department of Medical and Surgical Sciences of the Mother, Children and Adults. University of Modena and Reggio Emilia, Via del Pozzo n. 71, 41124 Modena, Italy
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20
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Hill JL, Jimenez DV, Mai Y, Ren M, Hallock HL, Maynard KR, Chen HY, Hardy NF, Schloesser RJ, Maher BJ, Yang F, Martinowich K. Cortistatin-expressing interneurons require TrkB signaling to suppress neural hyper-excitability. Brain Struct Funct 2018; 224:471-483. [PMID: 30377803 DOI: 10.1007/s00429-018-1783-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 10/21/2018] [Indexed: 01/12/2023]
Abstract
Signaling of brain-derived neurotrophic factor (BDNF) via tropomyosin receptor kinase B (TrkB) plays a critical role in the maturation of cortical inhibition and controls expression of inhibitory interneuron markers, including the neuropeptide cortistatin (CST). CST is expressed exclusively in a subset of cortical and hippocampal GABAergic interneurons, where it has anticonvulsant effects and controls sleep slow-wave activity (SWA). We hypothesized that CST-expressing interneurons play a critical role in regulating excitatory/inhibitory balance, and that BDNF, signaling through TrkB receptors on CST-expressing interneurons, is required for this function. Ablation of CST-expressing cells caused generalized seizures and premature death during early postnatal development, demonstrating a critical role for these cells in providing inhibition. Mice in which TrkB was selectively deleted from CST-expressing interneurons were hyperactive, slept less and developed spontaneous seizures. Frequencies of spontaneous excitatory post-synaptic currents (sEPSCs) on CST-expressing interneurons were attenuated in these mice. These data suggest that BDNF, signaling through TrkB receptors on CST-expressing cells, promotes excitatory drive onto these cells. Loss of excitatory drive onto CST-expressing cells that lack TrkB receptors may contribute to observed hyperexcitability and epileptogenesis.
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Affiliation(s)
- Julia L Hill
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Dennisse V Jimenez
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Yishan Mai
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Ming Ren
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Henry L Hallock
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Kristen R Maynard
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Huei-Ying Chen
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Nicholas F Hardy
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | | | - Brady J Maher
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA.,Departments of Psychiatry and Behavioral Sciences, and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Feng Yang
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA
| | - Keri Martinowich
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, 855 North Wolfe Street, Suite 300, Baltimore, MD, 21205, USA. .,Departments of Psychiatry and Behavioral Sciences, and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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21
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Mehrabi S, Sanadgol N, Barati M, Shahbazi A, Vahabzadeh G, Barzroudi M, Seifi M, Gholipourmalekabadi M, Golab F. Evaluation of metformin effects in the chronic phase of spontaneous seizures in pilocarpine model of temporal lobe epilepsy. Metab Brain Dis 2018; 33:107-114. [PMID: 29080083 DOI: 10.1007/s11011-017-0132-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 10/09/2017] [Indexed: 11/28/2022]
Abstract
Temporal lobe epilepsy (TLE) is a common form of drug-resistant epilepsy that sometimes responds to dietary manipulation such as the 'ketogenic diet'. Here we have investigated the effects of metformin in the rat pilocaroin model of TLE. Male rats were treated with intra peritoneal injection of pilocarpine hydrochloride, in dose of 360 mg/kg to induce status epilepticus (SE). At 45 day after induction of SE, metformin was injected intraperitoneally in dose of 250 mg/kg/day for 5 days. We show that metformin potently reduces the progression of seizures and blocks seizure-induced over-expression of brain-derived neurotropic factor (BDNF) and its receptor, Tropomyosin receptor kinase B (TrkB). We have shown that this reduced expression pattern is mediated by the transcriptional co-repressor CtBP (C-terminal binding protein). Moreover, metformin decreased mechanistic target of rapamycin (mTOR) activation through activation of AMP-activated protein kinase (AMPK) signaling pathway. Our findings have been shown that metformin has anticonvulsant and antiepileptic properties, and suggesting that antiglycolytic compounds such as metformin may represent a new class of drugs for treating epilepsy.
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Affiliation(s)
- Soraya Mehrabi
- Cellular and Molecular Research Center, Iran University of Medical Science, Tehran, Iran
| | - Nima Sanadgol
- Department of Biology, Faculty of Sciences, University of Zabol, Zabol, Iran
- Young Researchers and Elite Club, Zahedan Branch, Islamic Azad University, Zahedan, Iran
| | - Mahmood Barati
- Department of Biotechnology, Faculty of Allied Medicine, Iran University of Medical Science, Tehran, Iran
| | - Ali Shahbazi
- Faculty of Advanced Technologies in Medicine, Department of Neuroscience, Iran University of Medical Sciences, Tehran, Iran
| | - Gelareh Vahabzadeh
- Cellular and Molecular Research Center, Iran University of Medical Science, Tehran, Iran
- Department of Pharmacology, Iran University of Medical Sciences, Tehran, Iran
| | - Mitra Barzroudi
- Department of Anatomy, Iran University of Medical Sciences, Tehran, Iran
| | - Morteza Seifi
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Mazaher Gholipourmalekabadi
- Department of Tissue Engineering & Regenerative Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Fereshteh Golab
- Cellular and Molecular Research Center, Iran University of Medical Science, Tehran, Iran.
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22
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Kinboshi M, Mukai T, Nagao Y, Matsuba Y, Tsuji Y, Tanaka S, Tokudome K, Shimizu S, Ito H, Ikeda A, Inanobe A, Kurachi Y, Inoue S, Ohno Y. Inhibition of Inwardly Rectifying Potassium (Kir) 4.1 Channels Facilitates Brain-Derived Neurotrophic Factor (BDNF) Expression in Astrocytes. Front Mol Neurosci 2017; 10:408. [PMID: 29358904 PMCID: PMC5768989 DOI: 10.3389/fnmol.2017.00408] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/24/2017] [Indexed: 11/16/2022] Open
Abstract
Inwardly rectifying potassium (Kir) 4.1 channels in astrocytes regulate neuronal excitability by mediating spatial potassium buffering. Although dysfunction of astrocytic Kir4.1 channels is implicated in the development of epileptic seizures, the functional mechanisms of Kir4.1 channels in modulating epileptogenesis remain unknown. We herein evaluated the effects of Kir4.1 inhibition (blockade and knockdown) on expression of brain-derived neurotrophic factor (BDNF), a key modulator of epileptogenesis, in the primary cultures of mouse astrocytes. For blockade of Kir4.1 channels, we tested several antidepressant agents which reportedly bound to and blocked Kir4.1 channels in a subunit-specific manner. Treatment of astrocytes with fluoxetine enhanced BDNF mRNA expression in a concentration-dependent manner and increased the BDNF protein level. Other antidepressants (e.g., sertraline and imipramine) also increased the expression of BDNF mRNA with relative potencies similar to those for inhibition of Kir4.1 channels. In addition, suppression of Kir4.1 expression by the transfection of small interfering RNA (siRNA) targeting Kir4.1 significantly increased the mRNA and protein levels of BDNF. The BDNF induction by Kir4.1 siRNA transfection was suppressed by the MEK1/2 inhibitor U0126, but not by the p38 MAPK inhibitor SB202190 or the JNK inhibitor SP600125. The present results demonstrated that inhibition of Kir4.1 channels facilitates BDNF expression in astrocytes primarily by activating the Ras/Raf/MEK/ERK pathway, which may be linked to the development of epilepsy and other neuropsychiatric disorders.
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Affiliation(s)
- Masato Kinboshi
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan.,Department of Neurology, Wakayama Medical University, Wakayama, Japan.,Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takahiro Mukai
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Yuki Nagao
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Yusuke Matsuba
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Yoshimi Tsuji
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Shiho Tanaka
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Kentaro Tokudome
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan.,Department of Molecular and Cellular Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Saki Shimizu
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Hidefumi Ito
- Department of Neurology, Wakayama Medical University, Wakayama, Japan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Atsushi Inanobe
- Department of Molecular and Cellular Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yoshihisa Kurachi
- Department of Molecular and Cellular Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Seiji Inoue
- Education and Research Center for Fundamental Pharmaceutical Sciences, Osaka University of Pharmaceutical Sciences, Osaka, Japan
| | - Yukihiro Ohno
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Osaka, Japan
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23
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Novel Targets for Developing Antiseizure and, Potentially, Antiepileptogenic Drugs. Epilepsy Curr 2017; 17:293-298. [PMID: 29225544 DOI: 10.5698/1535-7597.17.5.293] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Epilepsy is a chronic neurological disorder caused by abnormal changes in the functions of neuronal circuits and manifested by seizures. It affects patients of all age, substantially worsens the quality of life for the patients as well as their families, and imposes a huge economic burden on the healthcare system. Historically, efforts for discovering and developing antiseizure therapies have been focused on modulating the functions of receptors, transporters, and enzymes expressed by neurons. These drug development efforts have paid off, as we have over 25 antiseizure drugs available in the clinic. However, these drugs mainly provide symptomatic relief from seizures and often cause serious adverse effects. Importantly, almost one-third of patients with epilepsy do not have their seizures adequately controlled by available drugs. To address this problem, researchers are investigating cellular and molecular mechanisms fundamental to the optimal function of neuronal circuits. Evidence shows that disruptions in these mechanisms cause impairment in neuroglial interactions, uncontrolled inflammation, aberrant synaptogenesis, and neurodegeneration in genetic and acquired epilepsies. Many novel therapeutic targets have been identified to target these mechanisms for developing new antiseizure drugs. In addition, the field is exploring new drug targets which may impede the development of epilepsy. We have summarized some of these novel targets in this brief review.
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24
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Clossen BL, Reddy DS. Novel therapeutic approaches for disease-modification of epileptogenesis for curing epilepsy. Biochim Biophys Acta Mol Basis Dis 2017; 1863:1519-1538. [PMID: 28179120 PMCID: PMC5474195 DOI: 10.1016/j.bbadis.2017.02.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/31/2017] [Accepted: 02/03/2017] [Indexed: 11/16/2022]
Abstract
This article describes the recent advances in epileptogenesis and novel therapeutic approaches for the prevention of epilepsy, with a special emphasis on the pharmacological basis of disease-modification of epileptogenesis for curing epilepsy. Here we assess animal studies and human clinical trials of epilepsy spanning 1982-2016. Epilepsy arises from a number of neuronal factors that trigger epileptogenesis, which is the process by which a brain shifts from a normal physiologic state to an epileptic condition. The events precipitating these changes can be of diverse origin, including traumatic brain injury, cerebrovascular damage, infections, chemical neurotoxicity, and emergency seizure conditions such as status epilepticus. Expectedly, the molecular and system mechanisms responsible for epileptogenesis are not well defined or understood. To date, there is no approved therapy for the prevention of epilepsy. Epigenetic dysregulation, neuroinflammation, and neurodegeneration appear to trigger epileptogenesis. Targeted drugs are being identified that can truly prevent the development of epilepsy in at-risk people. The promising agents include rapamycin, COX-2 inhibitors, TRK inhibitors, epigenetic modulators, JAK-STAT inhibitors, and neurosteroids. Recent evidence suggests that neurosteroids may play a role in modulating epileptogenesis. A number of promising drugs are under investigation for the prevention or modification of epileptogenesis to halt the development of epilepsy. Some drugs in development appear rational for preventing epilepsy because they target the initial trigger or related signaling pathways as the brain becomes progressively more prone to seizures. Additional research into the target validity and clinical investigation is essential to make new frontiers in curing epilepsy.
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Affiliation(s)
- Bryan L Clossen
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX 77807, USA.
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25
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Zinc Interactions With Brain-Derived Neurotrophic Factor and Related Peptide Fragments. VITAMINS AND HORMONES 2017; 104:29-56. [DOI: 10.1016/bs.vh.2016.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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26
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A novel P2X4 receptor-selective antagonist produces anti-allodynic effect in a mouse model of herpetic pain. Sci Rep 2016; 6:32461. [PMID: 27576299 PMCID: PMC5006034 DOI: 10.1038/srep32461] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/09/2016] [Indexed: 01/09/2023] Open
Abstract
Accumulating evidence indicates that purinergic P2X4 receptors (P2X4R: cation channels activated by extracellular ATP) expressed in spinal microglia are crucial for pathological chronic pain caused by nerve damage, suggesting a potential target for drug discovery. We identified NP-1815-PX (5-[3-(5-thioxo-4H-[1,2,4]oxadiazol-3-yl)phenyl]-1H-naphtho[1, 2-b][1,4]diazepine-2,4(3H,5H)-dione) as a novel antagonist selective for P2X4R with high potency and selectivity compared with other P2XR subtypes. In in vivo assay for acute and chronic pain, intrathecal administration of NP-1815-PX produced an anti-allodynic effect in mice with traumatic nerve damage without affecting acute nociceptive pain and motor function (although its oral administration did not produce the effect). Furthermore, in a mouse model of herpetic pain, P2X4R upregulation in the spinal cord exclusively occurred in microglia, and intrathecal NP-1815-PX suppressed induction of mechanical allodynia. This model also showed K+/Cl− cotransporter 2 (KCC2) downregulation, which is implicated in dorsal horn neuron hyperexcitability; this downregulation was restored by intrathecal treatment with NP-1815-PX or by interfering with brain-derived neurotrophic factor (BDNF) signaling, a P2X4R-activated microglial factor implicated in KCC2 downregulation. Taken together, the newly developed P2X4R antagonist NP-1815-PX produces anti-allodynic effects in chronic pain models without altering acute pain sensitivity, suggesting that microglial P2X4R could be an attractive target for treating chronic pain.
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27
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Xiang L, Ren Y, Li X, Zhao W, Song Y. MicroRNA-204 suppresses epileptiform discharges through regulating TrkB-ERK1/2-CREB signaling in cultured hippocampal neurons. Brain Res 2016; 1639:99-107. [DOI: 10.1016/j.brainres.2016.02.045] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/19/2016] [Accepted: 02/25/2016] [Indexed: 01/14/2023]
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28
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Shah AP, Carreno FR, Wu H, Chung YA, Frazer A. Role of TrkB in the anxiolytic-like and antidepressant-like effects of vagal nerve stimulation: Comparison with desipramine. Neuroscience 2016; 322:273-86. [PMID: 26899129 DOI: 10.1016/j.neuroscience.2016.02.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 01/23/2016] [Accepted: 02/09/2016] [Indexed: 12/27/2022]
Abstract
A current hypothesis regarding the mechanism of antidepressant (AD) action suggests the involvement of brain-derived neurotrophic factor (BDNF). Consistent with this hypothesis, the receptor for BDNF (and neurotrophin 4/5 (NT-4/5)), Tropomyosin-related kinase B (TrkB), is activated in rodents by treatment with classical AD drugs. Vagal nerve stimulation (VNS), a therapy for treatment resistant depression (TRD), also activates TrkB in rodents. However, the role of this receptor in the therapeutic effects of VNS is unclear. In the current study, the involvement of TrkB in the effects of VNS was investigated in rats using its inhibitor, K252a. Anxiolytic-like and AD-like effects were analyzed using the novelty suppressed feeding test (NSFT) and forced swim test (FST), respectively. K252a blocked the anxiolytic-like effect of chronic VNS treatment and the AD-like effect of acute VNS treatment. By contrast, blocking TrkB did not prevent either the anxiolytic-like or AD-like effect of chronic treatment with desipramine (DMI), a selective noradrenergic reuptake inhibitor; it did, however, block the acute effect of DMI in the FST. To examine whether the activation of TrkB caused by either VNS or DMI is ligand-dependent, use was made of TrkB-Fc, a molecular scavenger for ligands of TrkB. Intraventricular administration of TrkB-Fc blocked the acute activation of TrkB induced by either treatment, indicating that treatment-induced activation of this receptor is ligand-dependent. The behavioral results highlight differences in the involvement of TrkB in the chronic effects of an AD drug and a stimulation therapy as well as its role in acute versus chronic effects of DMI.
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Affiliation(s)
- A P Shah
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, TX, USA.
| | - F R Carreno
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, TX, USA
| | - H Wu
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, TX, USA
| | - Y A Chung
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, TX, USA
| | - A Frazer
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, TX, USA; South Texas Veterans Health Care System (STVHCS), Audie L. Murphy Division, San Antonio, TX, USA
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29
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Yang M, Ozturk E, Salzberg MR, Rees S, Morris M, O'Brien TJ, Jones NC. Environmental enrichment delays limbic epileptogenesis and restricts pathologic synaptic plasticity. Epilepsia 2016; 57:484-94. [DOI: 10.1111/epi.13299] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2015] [Indexed: 12/30/2022]
Affiliation(s)
- Meng Yang
- Department of Medicine (Royal Melbourne Hospital); Melbourne Brain Centre; The University of Melbourne; Melbourne Victoria Australia
| | - Ezgi Ozturk
- Department of Medicine (Royal Melbourne Hospital); Melbourne Brain Centre; The University of Melbourne; Melbourne Victoria Australia
| | - Michael R. Salzberg
- Department of Medicine (Royal Melbourne Hospital); Melbourne Brain Centre; The University of Melbourne; Melbourne Victoria Australia
- Department of Psychiatry; St Vincent's Hospital; Melbourne Victoria Australia
| | - Sandra Rees
- Department of Anatomy and Neuroscience; University of Melbourne; Melbourne Victoria Australia
| | - Margaret Morris
- Department of Pharmacology; UNSW Australia; Sydney New South Wales Australia
| | - Terence J. O'Brien
- Department of Medicine (Royal Melbourne Hospital); Melbourne Brain Centre; The University of Melbourne; Melbourne Victoria Australia
| | - Nigel C. Jones
- Department of Medicine (Royal Melbourne Hospital); Melbourne Brain Centre; The University of Melbourne; Melbourne Victoria Australia
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30
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Poddar R, Rajagopal S, Shuttleworth CW, Paul S. Zn2+-dependent Activation of the Trk Signaling Pathway Induces Phosphorylation of the Brain-enriched Tyrosine Phosphatase STEP: MOLECULAR BASIS FOR ZN2+-INDUCED ERK MAPK ACTIVATION. J Biol Chem 2015; 291:813-25. [PMID: 26574547 DOI: 10.1074/jbc.m115.663468] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Indexed: 11/06/2022] Open
Abstract
Excessive release of Zn(2+) in the brain is implicated in the progression of acute brain injuries. Although several signaling cascades have been reported to be involved in Zn(2+)-induced neurotoxicity, a potential contribution of tyrosine phosphatases in this process has not been well explored. Here we show that exposure to high concentrations of Zn(2+) led to a progressive increase in phosphorylation of the striatal-enriched phosphatase (STEP), a component of the excitotoxic-signaling pathway that plays a role in neuroprotection. Zn(2+)-mediated phosphorylation of STEP61 at multiple sites (hyperphosphorylation) was induced by the up-regulation of brain-derived neurotropic factor (BDNF), tropomyosin receptor kinase (Trk) signaling, and activation of cAMP-dependent PKA (protein kinase A). Mutational studies further show that differential phosphorylation of STEP61 at the PKA sites, Ser-160 and Ser-221 regulates the affinity of STEP61 toward its substrates. Consistent with these findings we also show that BDNF/Trk/PKA mediated signaling is required for Zn(2+)-induced phosphorylation of extracellular regulated kinase 2 (ERK2), a substrate of STEP that is involved in Zn(2+)-dependent neurotoxicity. The strong correlation between the temporal profile of STEP61 hyperphosphorylation and ERK2 phosphorylation indicates that loss of function of STEP61 through phosphorylation is necessary for maintaining sustained ERK2 phosphorylation. This interpretation is further supported by the findings that deletion of the STEP gene led to a rapid and sustained increase in ERK2 phosphorylation within minutes of exposure to Zn(2+). The study provides further insight into the mechanisms of regulation of STEP61 and also offers a molecular basis for the Zn(2+)-induced sustained activation of ERK2.
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Affiliation(s)
| | | | - C William Shuttleworth
- Neurosciences University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Surojit Paul
- From the Departments of Neurology and Neurosciences University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
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31
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Zhu X, Dong J, Shen K, Bai Y, Zhang Y, Lv X, Chao J, Yao H. NMDA receptor NR2B subunits contribute to PTZ-kindling-induced hippocampal astrocytosis and oxidative stress. Brain Res Bull 2015; 114:70-8. [DOI: 10.1016/j.brainresbull.2015.04.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 03/30/2015] [Accepted: 04/06/2015] [Indexed: 12/29/2022]
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32
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Wistar Audiogenic Rats (WAR) exhibit altered levels of cytokines and brain-derived neurotrophic factor following audiogenic seizures. Neurosci Lett 2015; 597:154-8. [PMID: 25936592 DOI: 10.1016/j.neulet.2015.04.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/13/2015] [Accepted: 04/27/2015] [Indexed: 01/02/2023]
Abstract
Increasing body of evidence suggests that inflammatory and neurotrophic factors might be important for epileptogenesis. Most animal studies demonstrated altered levels of these mediators in drug-induced models of seizures and epilepsy. In the present study, we investigated the production of cytokines and a neurotrophin in the brain of Wistar Audiogenic Rats (WAR), a genetic model of epilepsy, stimulated with high-intensity sound. Four hours after stimulation, animals were decapitated and the hippocampus, inferior colliculus, striatum and cortex were removed for evaluation of the levels of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and brain derived neurotrophic factor (BDNF). All the cytokines and BDNF levels were increased in the cortex. Increased levels of TNF-α and IL-6 were also observed in the striatum. Finally, TNF-α also increased in the inferior colliculus after the seizures induced by high-intensity sound. Although different studies have demonstrated that the levels of cytokines and BDNF increase in animal models of epilepsy induced by chemical stimuli, we provided here evidence that these mediators are also increased in WAR, a genetic model of epilepsy. Thus, the observed increase in these mediators might be involved in the pathophysiology of epilepsy.
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33
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Reimers JM, Loweth JA, Wolf ME. BDNF contributes to both rapid and homeostatic alterations in AMPA receptor surface expression in nucleus accumbens medium spiny neurons. Eur J Neurosci 2014; 39:1159-69. [PMID: 24712995 DOI: 10.1111/ejn.12422] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 09/30/2013] [Accepted: 10/12/2013] [Indexed: 12/15/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) plays a critical role in plasticity at glutamate synapses and in the effects of repeated cocaine exposure. We recently showed that intracranial injection of BDNF into the rat nucleus accumbens (NAc), a key region for cocaine addiction, rapidly increases α-amino-3-hyroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) surface expression. To further characterize BDNF's role in both rapid AMPAR trafficking and slower, homeostatic changes in AMPAR surface expression, we investigated the effects of acute (30 min) and long-term (24 h) treatment with BDNF on AMPAR distribution in NAc medium spiny neurons from postnatal rats co-cultured with mouse prefrontal cortex neurons to restore excitatory inputs. Immunocytochemical studies showed that acute BDNF treatment increased cell surface GluA1 and GluA2 levels, as well as their co-localization, on NAc neurons. This effect of BDNF, confirmed using a protein crosslinking assay, was dependent on ERK but not AKT signaling. In contrast, long-term BDNF treatment decreased AMPAR surface expression on NAc neurons. Based on this latter result, we tested the hypothesis that BDNF plays a role in AMPAR 'scaling down' in response to a prolonged increase in neuronal activity produced by bicuculline (24 h). Supporting this hypothesis, decreasing BDNF signaling with the extracellular BDNF scavenger TrkB-Fc prevented the scaling down of GluA1 and GluA2 surface levels in NAc neurons normally produced by bicuculline. In conclusion, BDNF exerts bidirectional effects on NAc AMPAR surface expression, depending on duration of exposure. Furthermore, BDNF's involvement in synaptic scaling in the NAc differs from its previously described role in the visual cortex.
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Affiliation(s)
- Jeremy M Reimers
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL, 60064-3095, USA
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34
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Zhou Y, Oudin MJ, Gajendra S, Sonego M, Falenta K, Williams G, Lalli G, Doherty P. Regional effects of endocannabinoid, BDNF and FGF receptor signalling on neuroblast motility and guidance along the rostral migratory stream. Mol Cell Neurosci 2014; 64:32-43. [PMID: 25481343 PMCID: PMC4324876 DOI: 10.1016/j.mcn.2014.12.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/28/2014] [Accepted: 12/02/2014] [Indexed: 01/09/2023] Open
Abstract
During development and after birth neural stem cells in the subventricular zone (SVZ) generate neuroblasts that migrate along the rostral migratory stream (RMS) to populate the olfactory bulb (OB) with neurons. Multiple factors promote neuroblast migration, but the contribution that many of these make to guidance within the intact RMS is not known. In the present study we have characterised in detail how endocannabinoid (eCB), BDNF and FGF receptor (FGFR) signalling regulates motility and guidance, and also determined whether any of these receptors operate in a regionally restricted manner. We used in vivo electroporation in postnatal mice to fluorescently label neuroblasts, and live cell imaging to detail their migratory properties. Cannabinoid receptor antagonists rendered neuroblasts less mobile, and when they did move guidance was lost. Similar results were obtained when eCB synthesis was blocked with diacylglycerol lipase (DAGL) inhibitors, and importantly eCB function is required for directed migration at both ends of the RMS. Likewise, inhibition of BDNF signalling disrupted motility and guidance in a similar manner along the entire RMS. In contrast, altering FGFR signalling inhibits motility and perturbs guidance, but only at the beginning of the stream. Inhibition of FGFR signalling in vivo also reduces the length of the leading process on migratory neuroblasts in a graded manner along the RMS. These results provide evidence for a guidance function for all three of the above receptor systems in the intact RMS, but show that FGFR signalling is unique as it is required in a regionally specific manner.
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Affiliation(s)
- Ya Zhou
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Madeleine J Oudin
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Sangeetha Gajendra
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Martina Sonego
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Katarzyna Falenta
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Gareth Williams
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Giovanna Lalli
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom.
| | - Patrick Doherty
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom.
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35
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Post-status epilepticus treatment with the cannabinoid agonist WIN 55,212-2 prevents chronic epileptic hippocampal damage in rats. Neurobiol Dis 2014; 73:356-65. [PMID: 25447228 DOI: 10.1016/j.nbd.2014.10.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/13/2014] [Accepted: 10/17/2014] [Indexed: 12/12/2022] Open
Abstract
Repeated seizures are often associated with development of refractory chronic epilepsy, the most common form of which is temporal lobe epilepsy. G-protein-coupled cannabinoid receptors (CB1 and CB2 receptors) regulate neuronal excitability and have been shown to mediate acute anticonvulsant effects of cannabinoids in animal models. However, the potential of cannabinoids to prevent chronic neuronal damage and development of epilepsy remains unexplored. We hypothesized that treatment with a CB receptor agonist after an episode of status epilepticus--but before development of spontaneous recurrent seizures--might prevent the development of functional changes that lead to chronic epilepsy. Using the rat pilocarpine model, a therapeutic approach was simulated by administering the CB agonist, WIN 55,212-2 after an episode of status epilepticus. Epileptic behavior was monitored during development of spontaneous recurrent seizures for up to 6 months. Histology, neurochemistry, redox status and NMDA receptor subunit expression were assessed at 6 months after pilocarpine-induced seizures. Sub-acute treatment with WIN 55,212-2 (for 15 days starting 24h after PILO injection) dramatically attenuated the severity, duration and frequency of spontaneous recurrent seizures. Further, in contrast to vehicle-treated animals, hippocampi from WIN 55,212-2-treated animals showed: normal thiol redox state, normal NR2A and NR2B subunit expression, preservation of GABAergic neurons and prevention of abnormal proliferation of GABAergic progenitors. This study shows for the first time that, after a known inciting event, treatment with a compound targeting CB receptors has the potential to prevent the epileptogenic events that result in chronic epileptic damage.
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Varvel NH, Jiang J, Dingledine R. Candidate drug targets for prevention or modification of epilepsy. Annu Rev Pharmacol Toxicol 2014; 55:229-47. [PMID: 25196047 DOI: 10.1146/annurev-pharmtox-010814-124607] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Epilepsy is a prevalent neurological disorder afflicting nearly 50 million people worldwide. The disorder is characterized clinically by recurrent spontaneous seizures attributed to abnormal synchrony of brain neurons. Despite advances in the treatment of epilepsy, nearly one-third of patients are resistant to current therapies, and the underlying mechanisms whereby a healthy brain becomes epileptic remain unresolved. Therefore, researchers have a major impetus to identify and exploit new drug targets. Here we distinguish between epileptic effectors, or proteins that set the seizure threshold, and epileptogenic mediators, which control the expression or functional state of the effector proteins. Under this framework, we then discuss attempts to regulate the mediators to control epilepsy. Further insights into the complex processes that render the brain susceptible to seizures and the identification of novel mediators of these processes will lead the way to the development of drugs to modify disease outcome and, potentially, to prevent epileptogenesis.
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Affiliation(s)
- Nicholas H Varvel
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322;
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Kandratavicius L, Hallak JE, Carlotti CG, Assirati JA, Leite JP. Neurotrophin receptors expression in mesial temporal lobe epilepsy with and without psychiatric comorbidities and their relation with seizure type and surgical outcome. Acta Neuropathol Commun 2014; 2:81. [PMID: 25027171 PMCID: PMC4149196 DOI: 10.1186/s40478-014-0081-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 06/29/2014] [Indexed: 12/30/2022] Open
Abstract
Epilepsy and psychiatric comorbidities are frequently associated, but their common biological substrate is unknown. We have previously reported altered structural elements and neurotrophins (NTs) expression in mesial temporal lobe epilepsy (MTLE) patients with psychiatric comorbidities. NTs receptors can regulate neurotransmission and promote neuroplasticity, being important candidates in the regulation and manifestation of psychopatological states and seizure-related events. MTLE hippocampi of subjects without psychiatric history, MTLE + major depression, MTLE + interictal psychosis derived from epilepsy surgery, and control necropsies were investigated for p75NTR, TrkB, TrkA, and TrkC immunohistochemistry. Increased expression of p75NTR, decreased TrkA, unaltered TrkC, and complex alterations involving TrkB expression were seen in MTLE groups. Increased TrkB expression in patients without complete seizure remission and in those with secondarily generalized seizures was seen. Decreased p75NTR expression associated with interictal psychosis, and increased TrkB in those with psychosis or major depression was also reported, although their p75NTR/TrkB ratios were lower than in MTLE without psychiatric comorbidities. Our results provide evidence of alterations in expression of NTs receptors in the epileptogenic hippocampus that are differentially modulated in presence of psychiatric comorbidities. As already explored in animal models, even in chronic human MTLE increased TrkB expression, among other NT receptors alterations, may play a major role in seizure type, frequency and surgery outcome.
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Dynorphin up-regulation in the dentate granule cell mossy fiber pathway following chronic inhibition of GluN2B-containing NMDAR is associated with increased CREB (Ser 133) phosphorylation, but is independent of BDNF/TrkB signaling pathways. Mol Cell Neurosci 2014; 60:63-71. [PMID: 24769103 DOI: 10.1016/j.mcn.2014.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 03/06/2014] [Accepted: 04/14/2014] [Indexed: 12/21/2022] Open
Abstract
Emerging evidence suggests that neuronal responses to N-methyl-d-aspartate (NMDAR) activation/inactivation are influenced by subunit composition. For example, activation of synaptic NMDAR (comprised of GluN2A>GluN2B) phosphorylates cAMP-response-element-binding protein (CREB) at Ser 133, induces BDNF expression and promotes neuronal survival. Activation of extrasynaptic NMDAR (comprised of GluN2B>GluN2) dephosphorylates CREB (Ser 133), reduces BDNF expression and triggers neuronal death. These results led us to hypothesize that chronic inhibition of GluN2B-containing NMDAR would increase CREB (Ser 133) phosphorylation, increase BDNF levels and subsequently alter downstream dynorphin (DYN) and neuropeptide Y (NPY) expression. We focused on DYN and NPY because these neuropeptides can decrease excitatory neurotransmission and seizure occurrence and we reported previously that seizure-like events are reduced following chronic treatment with GluN2B antagonists. Consistent with our hypothesis, chronic treatment (17-21days) of hippocampal slice cultures with the GluN2B-selective antagonists ifenprodil or Ro25,6981 increased both CREB (Ser 133) phosphorylation and granule cell mossy fiber pathway DYN expression. Similar treatment with the non-subtype-selective NMDAR antagonists d-APV or memantine had no significant effect on either CREB (Ser 133) phosphorylation or DYN expression. In contrast to our hypothesis, BDNF levels were decreased following chronic treatment with Ro25,6981, but not ifenprodil, d-APV or memantine. Blockade of BDNF actions and TrkB activation did not significantly augment hilar DYN expression in vehicle-treated cultures and had no effect in Ro25,6981 treated cultures. These findings suggest that chronic exposure to GluN2B-selective NMDAR antagonists increased DYN expression through a putatively pCREB-dependent, but BDNF/TrkB-independent mechanism.
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Gill R, Chang PKY, Prenosil GA, Deane EC, McKinney RA. Blocking brain-derived neurotrophic factor inhibits injury-induced hyperexcitability of hippocampal CA3 neurons. Eur J Neurosci 2013; 38:3554-66. [DOI: 10.1111/ejn.12367] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 08/16/2013] [Accepted: 08/28/2013] [Indexed: 01/07/2023]
Affiliation(s)
- Raminder Gill
- Department of Pharmacology & Therapeutics; McGill University; Bellini Life Sciences Complex 3649 Promenade Sir William Osler Montreal QC Canada H3G 0B1
| | - Philip K.-Y. Chang
- Department of Pharmacology & Therapeutics; McGill University; Bellini Life Sciences Complex 3649 Promenade Sir William Osler Montreal QC Canada H3G 0B1
| | - George A. Prenosil
- Department of Pharmacology & Therapeutics; McGill University; Bellini Life Sciences Complex 3649 Promenade Sir William Osler Montreal QC Canada H3G 0B1
| | - Emily C. Deane
- Department of Neurology and Neurosurgery; McGill University; Montreal QC Canada
| | - Rebecca A. McKinney
- Department of Pharmacology & Therapeutics; McGill University; Bellini Life Sciences Complex 3649 Promenade Sir William Osler Montreal QC Canada H3G 0B1
- Department of Neurology and Neurosurgery; McGill University; Montreal QC Canada
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Helgager J, Liu G, McNamara JO. The cellular and synaptic location of activated TrkB in mouse hippocampus during limbic epileptogenesis. J Comp Neurol 2013; 521:499-521, Spc1. [PMID: 22987780 DOI: 10.1002/cne.23225] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 07/18/2012] [Accepted: 09/07/2012] [Indexed: 01/07/2023]
Abstract
Understanding the mechanisms of limbic epileptogenesis in cellular and molecular terms may provide novel therapeutic targets for its prevention. The neurotrophin receptor tropomyosin-related kinase B (TrkB) is thought to be critical for limbic epileptogenesis. Enhanced activation of TrkB, revealed by immunodetection of enhanced phosphorylated TrkB (pTrkB), a surrogate measure of its activation, has been identified within the hippocampus in multiple animal models. Knowledge of the cellular locale of activated TrkB is necessary to elucidate its functional consequences. Using an antibody selective to pTrkB in conjunction with confocal microscopy and cellular markers, we determined the cellular and subcellular locale of enhanced pTrkB induced by status epilepticus (SE) evoked by infusion of kainic acid into the amygdala of adult mice. SE induced enhanced pTrkB immunoreactivity in two distinct populations of principal neurons within the hippocampus-the dentate granule cells and CA1 pyramidal cells. Enhanced immunoreactivity within granule cells was found within mossy fiber axons and giant synaptic boutons. By contrast, enhanced immunoreactivity was found within apical dendritic shafts and spines of CA1 pyramidal cells. A common feature of this enhanced pTrkB at these cellular locales is its localization to excitatory synapses between excitatory neurons, presynaptically in the granule cells and postsynaptically in CA1 pyramidal cells. Long-term potentiation (LTP) is one cellular consequence of TrkB activation at these excitatory synapses that may promote epileptogenesis.
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Affiliation(s)
- Jeffrey Helgager
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA
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Scharfman HE, Binder DK. Aquaporin-4 water channels and synaptic plasticity in the hippocampus. Neurochem Int 2013; 63:702-11. [PMID: 23684954 DOI: 10.1016/j.neuint.2013.05.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 04/29/2013] [Accepted: 05/07/2013] [Indexed: 12/23/2022]
Abstract
Aquaporin-4 (AQP4) is the major water channel expressed in the central nervous system (CNS) and is primarily expressed in glial cells. Many studies have shown that AQP4 regulates the response of the CNS to insults or injury, but far less is known about the potential for AQP4 to influence synaptic plasticity or behavior. Recent studies have examined long-term potentiation (LTP), long-term depression (LTD), and behavior in AQP4 knockout (KO) and wild-type mice to gain more insight into its potential role. The results showed a selective effect of AQP4 deletion on LTP of the Schaffer collateral pathway in hippocampus using an LTP induction protocol that simulates pyramidal cell firing during theta oscillations (theta-burst stimulation; TBS). However, LTP produced by a different induction protocol was unaffected. There was also a defect in LTD after low frequency stimulation (LFS) in AQP4 KO mice. Interestingly, some slices from AQP4 KO mice exhibited LTD after TBS instead of LTP, or LTP following LFS instead of LTD. These data suggest that AQP4 and astrocytes influence the polarity of long-term synaptic plasticity (potentiation or depression). These potentially powerful roles expand the influence of AQP4 and astrocytes beyond the original suggestions related to regulation of extracellular potassium and water balance. Remarkably, AQP4 KO mice did not show deficits in basal transmission, suggesting specificity for long-term synaptic plasticity. The mechanism appears to be related to neurotrophins and specifically brain-derived neurotrophic factor (BDNF) because pharmacological blockade of neurotrophin trk receptors or scavenging ligands such as BDNF restored plasticity. The in vitro studies predicted effects in vivo of AQP4 deletion because AQP4 KO mice performed worse using a task that requires memory for the location of objects (object placement). However, performance on other hippocampal-dependent tasks was spared. The results suggest an unanticipated and selective role of AQP4 in synaptic plasticity and spatial memory, and underscore the growing appreciation of the role of glial cells in functions typically attributed to neurons. Implications for epilepsy are discussed because of the previous evidence that AQP4 influences seizures, and the role of synaptic plasticity in epileptogenesis.
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Affiliation(s)
- Helen E Scharfman
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Rd., Bldg. 35, Orangeburg, NY 10962, United States; Departments of Child and Adolescent Psychiatry, Physiology and Neuroscience, and Psychiatry, New York University Langone Medical Center, New York, NY 10016, United States
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Mantilla CB, Gransee HM, Zhan WZ, Sieck GC. Motoneuron BDNF/TrkB signaling enhances functional recovery after cervical spinal cord injury. Exp Neurol 2013; 247:101-9. [PMID: 23583688 DOI: 10.1016/j.expneurol.2013.04.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 04/02/2013] [Accepted: 04/03/2013] [Indexed: 01/09/2023]
Abstract
A C2 cervical spinal cord hemisection (SH) interrupts descending inspiratory-related drive to phrenic motoneurons located between C3 and C5 in rats, paralyzing the ipsilateral hemidiaphragm muscle. There is gradual recovery of rhythmic diaphragm muscle activity ipsilateral to cervical spinal cord injury over time, consistent with neuroplasticity and strengthening of spared, contralateral descending premotor input to phrenic motoneurons. Brain-derived neurotrophic factor (BDNF) signaling through the tropomyosin related kinase receptor subtype B (TrkB) plays an important role in neuroplasticity following spinal cord injury. We hypothesized that 1) increasing BDNF/TrkB signaling at the level of the phrenic motoneuron pool by intrathecal BDNF delivery enhances functional recovery of rhythmic diaphragm activity after SH, and 2) inhibiting BDNF/TrkB signaling by quenching endogenous neurotrophins with the soluble fusion protein TrkB-Fc or by knocking down TrkB receptor expression in phrenic motoneurons using intrapleurally-delivered siRNA impairs functional recovery after SH. Diaphragm EMG electrodes were implanted bilaterally to verify complete hemisection at the time of SH and 3days post-SH. After SH surgery in adult rats, an intrathecal catheter was placed at C4 to chronically infuse BDNF or TrkB-Fc using an implanted mini-osmotic pump. At 14days post-SH, all intrathecal BDNF treated rats (n=9) displayed recovery of ipsilateral hemidiaphragm EMG activity, compared to 3 out of 8 untreated SH rats (p<0.01). During eupnea, BDNF treated rats exhibited 76±17% of pre-SH root mean squared EMG vs. only 5±3% in untreated SH rats (p<0.01). In contrast, quenching endogenous BDNF with intrathecal TrkB-Fc treatment completely prevented functional recovery up to 14days post-SH (n=7). Immunoreactivity of the transcription factor cAMP response element-binding protein (CREB), a downstream effector of TrkB signaling, increased in phrenic motoneurons following BDNF treatment (n=6) compared to artificial cerebrospinal fluid treatment (n=6; p<0.001). Intrapleural injections of non-sense or TrkB siRNA were administered after SH to specifically target phrenic motoneurons. At 14days post-SH, none out of 9 TrkB siRNA treated rats displayed functional recovery compared to 5 out of 9 non-sense siRNA treated rats. These results indicate that BDNF/TrkB signaling in phrenic motoneuron pool plays a critical role in functional recovery after cervical spinal cord injury.
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Affiliation(s)
- Carlos B Mantilla
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
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Sakharnova TA, Vedunova MV, Mukhina IV. Brain-derived neurotrophic factor (BDNF) and its role in the functioning of the central nervous system. NEUROCHEM J+ 2012. [DOI: 10.1134/s1819712412030129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Soren Leonard A, Puranam RS, Helgager J, Liu G, McNamara JO. Conditional deletion of TrkC does not modify limbic epileptogenesis. Epilepsy Res 2012; 102:126-30. [PMID: 22980123 DOI: 10.1016/j.eplepsyres.2012.07.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 07/16/2012] [Accepted: 07/30/2012] [Indexed: 02/01/2023]
Abstract
The neurotrophin receptor, tropomyosin-related kinase B (TrkB), is required for epileptogenesis in the kindling model. The role of a closely related neurotrophin receptor, TrkC, in limbic epileptogenesis is unknown. We examined limbic epileptogenesis in the kindling model in TrkC conditional null mice, using a strategy that previously established a critical role of TrkB. Despite elimination of TrkC mRNA, no differences in development of kindling were detected between TrkC conditional null and wild type control mice. These findings reinforce the central role of TrkB as the principal neurotrophin receptor involved in limbic epileptogenesis.
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Affiliation(s)
- A Soren Leonard
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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Boulle F, Kenis G, Cazorla M, Hamon M, Steinbusch HWM, Lanfumey L, van den Hove DLA. TrkB inhibition as a therapeutic target for CNS-related disorders. Prog Neurobiol 2012; 98:197-206. [PMID: 22705453 DOI: 10.1016/j.pneurobio.2012.06.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 05/30/2012] [Accepted: 06/06/2012] [Indexed: 01/04/2023]
Abstract
The interaction of brain-derived neurotrophic factor (BDNF) with its tropomyosin-related kinase receptor B (TrkB) is involved in fundamental cellular processes including neuronal proliferation, differentiation and survival as well as neurotransmitter release and synaptic plasticity. TrkB signaling has been widely associated with beneficial, trophic effects and many commonly used psychotropic drugs aim to increase BDNF levels in the brain. However, it is likely that a prolonged increased TrkB activation is observed in many pathological conditions, which may underlie the development and course of clinical symptoms. Interestingly, genetic and pharmacological studies aiming at decreasing TrkB activation in rodent models mimicking human pathology have demonstrated a promising therapeutic landscape for TrkB inhibitors in the treatment of various diseases, e.g. central nervous system (CNS) disorders and several types of cancer. Up to date, only a few selective and potent TrkB inhibitors have been developed. As such, the use of crystallography and in silico approaches to model BDNF-TrkB interaction and to generate relevant pharmacophores represent powerful tools to develop novel compounds targeting the TrkB receptor.
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Affiliation(s)
- Fabien Boulle
- Department of Psychiatry and Neuropsychology, Maastricht University, European Graduate School for Neuroscience (EURON), Maastricht, The Netherlands
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Tan GH, Liu YY, Hu XL, Yin DM, Mei L, Xiong ZQ. Neuregulin 1 represses limbic epileptogenesis through ErbB4 in parvalbumin-expressing interneurons. Nat Neurosci 2011; 15:258-66. [DOI: 10.1038/nn.3005] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 11/07/2011] [Indexed: 02/08/2023]
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Abidin I, Yildirim M, Aydin-Abidin S, Kalay E, Cansu A, Akca M, Mittmann T. Penicillin induced epileptiform activity and EEG spectrum analysis of BDNF heterozygous mice: An in vivo electrophysiological study. Brain Res Bull 2011; 86:159-64. [DOI: 10.1016/j.brainresbull.2011.06.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 06/01/2011] [Accepted: 06/25/2011] [Indexed: 11/29/2022]
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Weidner KL, Goodman JH, Chadman KK, McCloskey DP. Aging-induced Seizure-related Changes to the Hippocampal Mossy Fiber Pathway in Forebrain Specific BDNF Overexpressing Mice. Aging Dis 2011; 2:308-317. [PMID: 22396883 PMCID: PMC3295075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Revised: 08/21/2011] [Accepted: 08/22/2011] [Indexed: 05/31/2023] Open
Abstract
Aging confers an increased risk for developing seizure activity, especially within brain regions that mediate learning and synaptic plasticity. Brain derived neurotrophic factor (BDNF) is a member of the neurotrophin family that has an important role in regulating growth and development of the nervous system. BDNF is upregulated after pharmacological seizure induction and this upregulation contributes to enhanced excitability of the hippocampal mossy fiber-CA3 pathway, which is accompanied by neuropeptide Y (NPY) upregulation. Mice overexpressing a BDNF transgene in forebrain neurons provide an avenue for understanding the role of neurotrophic support in the aged hippocampus. In this study BDNF transgenic (TG) mice were utilized to determine whether increased BDNF expression through genetic manipulation resulted in age-related changes in hippocampal excitability and NPY expression. Spontaneous behavioral seizures were observed in TG mice, but not WT mice, past 5 months of age and the severity of behavioral seizures increased with age. Electrophysiological investigation of hippocampal CA3 activity indicated that slices from aged TG mice (86%), but not age-matched WT mice, or young TG mice, showed epileptiform activity in response to either repeated paired pulse or high frequency (tetanic) stimulation. Electrophysiological results were supported by the observation of robust ectopic NPY immunoreactivity in hippocampal mossy fibers of most aged TG mice (57%), which was absent in age-matched WT mice and young TG mice. The results from this study indicate that forebrain restricted BDNF overexpression produces age-related changes in hyperexcitability and NPY immunoreactivity in mossy fiber-CA3 pathway. Together, these data suggest that the capability for BDNF to promote epileptogenesis is maintained, and may be enhanced, in the aging hippocampus.
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Affiliation(s)
- Kate L. Weidner
- Center for Developmental Neuroscience in Developmental Disabilities, College of Staten Island, CUNY, Staten Island, NY, 10314, USA
| | - Jeffrey H. Goodman
- Department of Developmental Neurobiology, New York State Institute for Basic Research, Staten Island, New York 10314, USA
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA
| | - Kathryn K. Chadman
- Department of Developmental Neurobiology, New York State Institute for Basic Research, Staten Island, New York 10314, USA
| | - Daniel P. McCloskey
- Center for Developmental Neuroscience in Developmental Disabilities, College of Staten Island, CUNY, Staten Island, NY, 10314, USA
- Department of Psychology, College of Staten Island, CUNY, Staten Island, NY, 10314, USA
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Epigenetic gene regulation in the adult mammalian brain: multiple roles in memory formation. Neurobiol Learn Mem 2011; 96:68-78. [PMID: 21419233 DOI: 10.1016/j.nlm.2011.03.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 02/25/2011] [Accepted: 03/04/2011] [Indexed: 12/24/2022]
Abstract
Brain-derived neurotrophic factor (bdnf) is one of numerous gene products necessary for long-term memory formation and dysregulation of bdnf has been implicated in the pathogenesis of cognitive and mental disorders. Recent work indicates that epigenetic-regulatory mechanisms including the markings of histone proteins and associated DNA remain labile throughout the life-span and represent an attractive molecular process contributing to gene regulation in the brain. In this review, important information will be discussed on epigenetics as a set of newly identified dynamic transcriptional mechanisms serving to regulate gene expression changes in the adult brain with particular emphasis on bdnf transcriptional readout in learning and memory formation. This review will also highlight evidence for the role of epigenetics in aberrant bdnf gene regulation in the pathogenesis of cognitive dysfunction associated with seizure disorders, Rett syndrome, Schizophrenia, and Alzheimer's disease. Such research offers novel concepts for understanding epigenetic transcriptional mechanisms subserving adult cognition and mental health, and furthermore promises novel avenues for therapeutic approach in the clinic.
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Increase in BDNF-mediated TrkB signaling promotes epileptogenesis in a mouse model of mesial temporal lobe epilepsy. Neurobiol Dis 2011; 42:35-47. [PMID: 21220014 DOI: 10.1016/j.nbd.2011.01.001] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 12/21/2010] [Accepted: 01/02/2011] [Indexed: 01/19/2023] Open
Abstract
Mesio-temporal lobe epilepsy (MTLE), the most common drug-resistant epilepsy syndrome, is characterized by the recurrence of spontaneous focal seizures after a latent period that follows, in most patients, an initial insult during early childhood. Many of the mechanisms that have been associated with the pathophysiology of MTLE are known to be regulated by brain-derived neurotrophic factor (BDNF) in the healthy brain and an excess of this neurotrophin could therefore play a critical role in MTLE development. However, such a function remains controversial as other studies revealed that BDNF could, on the contrary, exert protective effects regarding epilepsy development. In the present study, we further addressed the role of increased BDNF/TrkB signaling on the progressive development of hippocampal seizures in the mouse model of MTLE obtained by intrahippocampal injection of kainate. We show that hippocampal seizures progressively developed in the injected hippocampus during the first two weeks following kainate treatment, within the same time-frame as a long-lasting and significant increase of BDNF expression in dentate granule cells. To determine whether such a BDNF increase could influence hippocampal epileptogenesis via its TrkB receptors, we examined the consequences of (i) increased or (ii) decreased TrkB signaling on epileptogenesis, in transgenic mice overexpressing the (i) TrkB full-length or (ii) truncated TrkB-T1 receptors of BDNF. Epileptogenesis was significantly facilitated in mice with increased TrkB signaling but delayed in mutants with reduced TrkB signaling. In contrast, TrkB signaling did not influence granule cell dispersion, an important feature of this mouse model which is also observed in most MTLE patients. These results suggest that an increase in TrkB signaling, mediated by a long-lasting BDNF overexpression in the hippocampus, promotes epileptogenesis in MTLE.
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