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Zaki-Dizaji M, Abazari MF, Razzaghi H, Shkolnikov I, Christie BR. GRM7 deficiency, from excitotoxicity and neuroinflammation to neurodegeneration: Systematic review of GRM7 deficient patients. Brain Behav Immun Health 2024; 39:100808. [PMID: 38983774 PMCID: PMC11231722 DOI: 10.1016/j.bbih.2024.100808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 06/03/2024] [Accepted: 06/10/2024] [Indexed: 07/11/2024] Open
Abstract
The metabotropic glutamate receptor 7 (mGluR7) is a presynaptic G-protein-coupled glutamate receptor that modulates neurotransmitter release and synaptic plasticity at presynaptic terminals. It is encoded by GRM7, and recently variants have been identified in patients with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), developmental delay (DD), intellectual disability (ID), and brain malformations. To gain updated insights into the function of GRM7 and the phenotypic spectrum of genetic variations within this gene, we conducted a systematic review of relevant literature utilizing PubMed, Web of Science, and Scopus databases. Among the 14 articles meeting the inclusion criteria, a total of 42 patients (from 28 families) harboring confirmed mutations in the GRM7 gene have been documented. Specifically, there were 17 patients with heterozygous mutations, 20 patients with homozygous mutations, and 5 patients with compound heterozygous mutations. Common clinical features included intellectual behavioral disability, seizure/epilepsy, microcephaly, developmental delay, peripheral hypertonia and hypomyelination. Genotype-phenotype correlation was not clear and each variant had unique characteristics including gene dosage, mutant protein surface expression, and degradation pathway that result with a spectrum of phenotype manifestations through ASD or ADHD to severe DD/ID with brain malformations. Neuroinflammation may play a role in the development and/or progression of GRM7-related neurodegeneration along with excitotoxicity. The clinical and functional data presented here demonstrate that both autosomal dominant and recessive inheritance of GRM7 mutation can cause disease spectrum phenotypes through ASD or ADHD to severe DD/ID and seizure with brain malformations.
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Affiliation(s)
- Majid Zaki-Dizaji
- Human Genetics Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mohammad Foad Abazari
- Research Center for Clinical Virology, Tehran University of Medical Sciences, Tehran, Iran
- Island Medical Program, University of British Columbia, Victoria, British Columbia, Canada
| | - Hossein Razzaghi
- Human Genetics Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Irene Shkolnikov
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - Brian R Christie
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
- Island Medical Program, University of British Columbia, Victoria, British Columbia, Canada
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Li Z, Gao Z, Chang C, Gao Z. Anticonvulsive Effect of Glucosyl Xanthone Mangiferin on Pentylenetetrazol (PTZ)-Induced Seizure-Provoked Mice. Appl Biochem Biotechnol 2024; 196:2161-2175. [PMID: 37486538 DOI: 10.1007/s12010-023-04651-2] [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] [Accepted: 07/04/2023] [Indexed: 07/25/2023]
Abstract
Anxiety and depression are major side effects induced by currently available antiepileptic drugs; apart from this, they also diminish intelligence and language skills which cause hepatic failure, anemia, etc. Hence, in this study, we assessed antiepileptic effect of a phytochemical mangiferin. Epilepsy, a prevalent non communicable neurological disorder, affects infants and older population throughout the world. Epilepsy-induced comorbidities are more severe and if not treated cautiously lead to disability and even worse cases, mortality. The onset and duration of convulsion were observed. Seizure severity score was assessed by provoking kindling with 35 mg/kg PTZ. Prooxidants and antioxidants were measured to assess the antioxidant effect of mangiferin. Inflammatory markers were measured to determine the anti-inflammatory effect of mangiferin. The levels of neurotransmitters and ATPases were quantified to evaluate the neuroprotective effect of mangiferin. Mangiferin significantly decreased the onset and duration convulsion. It also decreased the seizure severity score, locomotor activity, and immobilization effectively. The excitatory neurotransmitter was reduced, and inhibitory neurotransmitter was increased in mice treated with mangiferin. Overall, our results confirm that mangiferin efficiently protects mice from PTZ-induced seizures. It can be subjected to further research to be prescribed as a potent antiepileptic drug.
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Affiliation(s)
- Zhaoxia Li
- Department of Pediatric, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250033, China
| | - Zhiliang Gao
- Department of Pediatric, Binzhou Hospital of Traditional Chinese Medicine, Binzhou, 256600, China
| | - Cong Chang
- Department of Rehabilitation Medicine, Binzhou Municipal Hospital, Binzhou, 256600, China
| | - Zhuanglei Gao
- Department of Gastrointestinal Surgery, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250033, China.
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Roustaei B, Zarezadeh S, Ghotbi-Ravandi AA. A review on epilepsy, current treatments, and potential of medicinal plants as an alternative treatment. Neurol Sci 2023; 44:4291-4306. [PMID: 37581769 DOI: 10.1007/s10072-023-07010-5] [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: 05/29/2023] [Accepted: 08/03/2023] [Indexed: 08/16/2023]
Abstract
Epilepsy is considered common neurological diseases that threaten the lives of millions of people all around the world. Since ancient times, different forms of medications have been used to treat this condition. Adverse events associated with treatments and the residence time of available drugs caused to search for safer and more efficient therapies and drugs remain one of the major areas of research interest for scientists. As one of the therapeutics with fewer side effects, plants and their essential oils can be considered replacements for existing treatments. Medicinal plants have proven to be an effective natural source of antiepileptic drugs; most of them have their mechanism of action by affecting GABA receptors in different paths. Cannabis indica and Cymbopogon winterianus are well-known plant species with antiepileptic activities. The current review presenting a list of plants with antiepileptic effects aims to pave the way for finding alternative drugs with fewer side effects for scientists.
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Affiliation(s)
- Bahar Roustaei
- Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran
| | - Somayeh Zarezadeh
- Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran
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Liebert A, Capon W, Pang V, Vila D, Bicknell B, McLachlan C, Kiat H. Photophysical Mechanisms of Photobiomodulation Therapy as Precision Medicine. Biomedicines 2023; 11:biomedicines11020237. [PMID: 36830774 PMCID: PMC9953702 DOI: 10.3390/biomedicines11020237] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 01/19/2023] Open
Abstract
Despite a significant focus on the photochemical and photoelectrical mechanisms underlying photobiomodulation (PBM), its complex functions are yet to be fully elucidated. To date, there has been limited attention to the photophysical aspects of PBM. One effect of photobiomodulation relates to the non-visual phototransduction pathway, which involves mechanotransduction and modulation to cytoskeletal structures, biophotonic signaling, and micro-oscillatory cellular interactions. Herein, we propose a number of mechanisms of PBM that do not depend on cytochrome c oxidase. These include the photophysical aspects of PBM and the interactions with biophotons and mechanotransductive processes. These hypotheses are contingent on the effect of light on ion channels and the cytoskeleton, the production of biophotons, and the properties of light and biological molecules. Specifically, the processes we review are supported by the resonant recognition model (RRM). This previous research demonstrated that protein micro-oscillations act as a signature of their function that can be activated by resonant wavelengths of light. We extend this work by exploring the local oscillatory interactions of proteins and light because they may affect global body circuits and could explain the observed effect of PBM on neuro-cortical electroencephalogram (EEG) oscillations. In particular, since dysrhythmic gamma oscillations are associated with neurodegenerative diseases and pain syndromes, including migraine with aura and fibromyalgia, we suggest that transcranial PBM should target diseases where patients are affected by impaired neural oscillations and aberrant brain wave patterns. This review also highlights examples of disorders potentially treatable with precise wavelengths of light by mimicking protein activity in other tissues, such as the liver, with, for example, Crigler-Najjar syndrome and conditions involving the dysregulation of the cytoskeleton. PBM as a novel therapeutic modality may thus behave as "precision medicine" for the treatment of various neurological diseases and other morbidities. The perspectives presented herein offer a new understanding of the photophysical effects of PBM, which is important when considering the relevance of PBM therapy (PBMt) in clinical applications, including the treatment of diseases and the optimization of health outcomes and performance.
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Affiliation(s)
- Ann Liebert
- Faculty of Medicine and Health, University of Sydney, Sydney 2006, Australia
- Adventist Hospital Group, Wahroonga 2076, Australia
- NICM Health Research Institute, Western Sydney University, Westmead 2145, Australia
- Correspondence:
| | - William Capon
- Faculty of Medicine and Health, University of Sydney, Sydney 2006, Australia
| | - Vincent Pang
- NICM Health Research Institute, Western Sydney University, Westmead 2145, Australia
| | - Damien Vila
- Faculty of Medicine of Montpellier-Nîmes, University of Montpellier, 34090 Montpellier, France
| | - Brian Bicknell
- NICM Health Research Institute, Western Sydney University, Westmead 2145, Australia
| | - Craig McLachlan
- Faculty of Health, Torrens University, Adelaide 5000, Australia
| | - Hosen Kiat
- NICM Health Research Institute, Western Sydney University, Westmead 2145, Australia
- Faculty of Health, Torrens University, Adelaide 5000, Australia
- Cardiac Health Institute, Sydney 2121, Australia
- ANU College of Health and Medicine, Australian National University, Canberra 2600, Australia
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie Park 2109, Australia
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Kang KW, Cho YW, Lee SK, Jung KY, Kim JH, Kim DW, Lee SA, Hong SB, Na IS, Lee SH, Baek WK, Choi SY, Kim MK. Multidimensional Early Prediction Score for Drug-Resistant Epilepsy. J Clin Neurol 2022; 18:553-561. [PMID: 36062773 PMCID: PMC9444554 DOI: 10.3988/jcn.2022.18.5.553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/16/2022] [Accepted: 03/16/2022] [Indexed: 11/17/2022] Open
Abstract
Background and Purpose Achieving favorable postoperative outcomes in patients with drug-resistant epilepsy (DRE) requires early referrals for preoperative examinations. The purpose of this study was to investigate the possibility of a user-friendly early DRE prediction model that is easy for nonexperts to utilize. Methods A two-step genotype analysis was performed, by applying 1) whole-exome sequencing (WES) to the initial test set (n=243) and 2) target sequencing to the validation set (n=311). Based on a multicenter case–control study design using the WES data set, 11 genetic and 2 clinical predictors were selected to develop the DRE risk prediction model. The early prediction scores for DRE (EPS-DRE) was calculated for each group of the selected genetic predictors (EPS-DREgen), clinical predictors (EPS-DREcln), and two types of predictor mix (EPS-DREmix) in both the initial test set and the validation set. Results The multidimensional EPS-DREmix of the predictor mix group provided a better match to the outcome data than did the unidimensional EPS-DREgen or EPS-DREcln. Unlike previous studies, the EPS-DREmix model was developed using only 11 genetic and 2 clinical predictors, but it exhibited good discrimination ability in distinguishing DRE from drug-responsive epilepsy. These results were verified using an unrelated validation set. Conclusions Our results suggest that EPS-DREmix has good performance in early DRE prediction and is a user-friendly tool that is easy to apply in real clinical trials, especially by nonexperts who do not have detailed knowledge or equipment for assessing DRE. Further studies are needed to improve the performance of the EPS-DREmix model.
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Affiliation(s)
- Kyung Wook Kang
- Department of Neurology, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea
| | - Yong Won Cho
- Department of Neurology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea
| | - Sang Kun Lee
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea Program in Neuroscience, Seoul National University College of Medicine, Seoul, Korea
| | - Ki-Young Jung
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea Program in Neuroscience, Seoul National University College of Medicine, Seoul, Korea
| | - Ji Hyun Kim
- Department of Neurology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea
| | - Dong Wook Kim
- Department of Neurology, Konkuk University School of Medicine, Seoul, Korea
| | - Sang-Ahm Lee
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Seung Bong Hong
- Department of Neurology, Samsung Medical Center, Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute (SBRI), Seoul, Korea.,National Epilepsy Care Center, Seoul, Korea
| | - In-Seop Na
- National Program of Excellence in Software Centre, Chosun University, Gwangju, Korea
| | - So-Hyun Lee
- Department of Biomedical Science, Chonnam National University Medical School, Hwasun, Korea
| | - Won-Ki Baek
- Department of Microbiology, Keimyung University School of Medicine, Daegu, Korea
| | - Seok-Yong Choi
- Department of Biomedical Science, Chonnam National University Medical School, Hwasun, Korea.
| | - Myeong-Kyu Kim
- Department of Neurology, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Korea.
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Li X, Wang Q, Zhang DW, Wu D, Zhang SW, Wei ZR, Chen X, Li W. Hippocampus RNA Sequencing of Pentylenetetrazole-Kindled Rats and Upon Treatment of Novel Chemical Q808. Front Pharmacol 2022; 13:820508. [PMID: 35345815 PMCID: PMC8957222 DOI: 10.3389/fphar.2022.820508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/01/2022] [Indexed: 12/04/2022] Open
Abstract
The expression of genes altered in epilepsy remains incomplete, particularly in the hippocampus, which exhibits exquisite vulnerability to epilepsy. Q808 is an innovation chemical compound that has potent anti-convulsant effect. Exploring its mechanism can not only explore the pathogenesis of epilepsy but also provide a theoretical basis for its clinical application. The present study aimed to use RNA sequencing (RNA-seq) to reveal the gene transcriptomic profile of chronic pentylenetetrazole (PTZ)-kindled seizure rats and the difference of the PTZ model rat before and after treatment with Q808. Quantitative real-time PCR (qRT-PCR) was performed to validate the RNA-seq results. The protein level was estimated with Western blot. Hippocampal transcriptomic analysis showed that 289 differentially expressed genes (DEGs) were confirmed in the PTZ-kindled seizure group compared with the vehicle control. Gene cluster analysis identified most of the DEGs linked to neuronal apoptosis, neurogenesis, neuronal projections, and neurotransmitter regulation. After analysis across the three groups, 23 hub genes and 21 pathways were identified, and qRT-PCR analysis confirmed that most of the mRNA levels of hub genes were consistent with the RNA-seq results. Q808 treatment increased the level of ACE, a GABA-related protein. Our analysis showed the comprehensive compendium of genes and pathways differentially expressed for PTZ-kindled seizure rats and upon Q808 treatment in PTZ-kindled seizure, which may provide a theoretical basis to explore the mechanism and unique efficacy of Q808 and the pathophysiology of epilepsy in the future.
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Affiliation(s)
- Xiang Li
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Qing Wang
- Jilin Provincial Academy of Traditional Chinese Medicine, Changchun, China
| | - Dian-Wen Zhang
- Jilin Provincial Academy of Traditional Chinese Medicine, Changchun, China
| | - Di Wu
- Jilin Provincial Academy of Traditional Chinese Medicine, Changchun, China
| | - Si-Wei Zhang
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Zheng-Ren Wei
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Xia Chen
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Wei Li
- Jilin Provincial Academy of Traditional Chinese Medicine, Changchun, China
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7
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Weng OY, Li Y, Wang LY. Modeling Epilepsy Using Human Induced Pluripotent Stem Cells-Derived Neuronal Cultures Carrying Mutations in Ion Channels and the Mechanistic Target of Rapamycin Pathway. Front Mol Neurosci 2022; 15:810081. [PMID: 35359577 PMCID: PMC8960276 DOI: 10.3389/fnmol.2022.810081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 02/02/2022] [Indexed: 11/17/2022] Open
Abstract
Epilepsy is a neurological disorder that affects over 65 million people globally. It is characterized by periods of seizure activity of the brain as a result of excitation and inhibition (E/I) imbalance, which is regarded as the core underpinning of epileptic activity. Both gain- and loss-of-function (GOF and LOF) mutations of ion channels, synaptic proteins and signaling molecules along the mechanistic target of rapamycin (mTOR) pathway have been linked to this imbalance. The pathogenesis of epilepsy often has its roots in the early stage of brain development. It remains a major challenge to extrapolate the findings from many animal models carrying these GOF or LOF mutations to the understanding of disease mechanisms in the developing human brain. Recent advent of the human pluripotent stem cells (hPSCs) technology opens up a new avenue to recapitulate patient conditions and to identify druggable molecular targets. In the following review, we discuss the progress, challenges and prospects of employing hPSCs-derived neural cultures to study epilepsy. We propose a tentative working model to conceptualize the possible impact of these GOF and LOF mutations in ion channels and mTOR signaling molecules on the morphological and functional remodeling of intrinsic excitability, synaptic transmission and circuits, ultimately E/I imbalance and behavioral phenotypes in epilepsy.
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Affiliation(s)
- Octavia Yifang Weng
- Program in Developmental and Stem Cell Biology, Sick Kids Research Institutes, Toronto, ON, Canada
- Program in Neuroscience and Mental Health, Sick Kids Research Institutes, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Yun Li
- Program in Developmental and Stem Cell Biology, Sick Kids Research Institutes, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- *Correspondence: Yun Li,
| | - Lu-Yang Wang
- Program in Neuroscience and Mental Health, Sick Kids Research Institutes, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Lu-Yang Wang,
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Silva MP, Rodrigues CG, Varanda WA, Nogueira RA. Memory in Ion Channel Kinetics. Acta Biotheor 2021; 69:697-722. [PMID: 34043104 DOI: 10.1007/s10441-021-09415-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 05/20/2021] [Indexed: 12/21/2022]
Abstract
Ion channels are transport proteins present in the lipid bilayers of biological membranes. They are involved in many physiological processes, such as the generation of nerve impulses, hormonal secretion, and heartbeat. Conformational changes in the ion channel-forming protein allow the opening or closing of pores to control the ionic flux through the cell membranes. The opening and closing of the ion channel have been classically treated as a random kinetic process, known as a Markov process. Here the time the channel remains in a given state is assumed to be independent of the condition it had in the previous state. More recently, however, several studies have shown that this process is not random but a deterministic one, where both the open and closed dwell-times and the ionic current flowing through the channel are history-dependent. This property is called long memory or long-range correlation. However, there is still much controversy regarding how this memory originates, which region of the channel is responsible for this property, and which models could best reproduce the memory effect. In this article, we provide a review of what is, where it is, its possible origin, and the mathematical methods used to analyze the long-term memory present in the kinetic process of ion channels.
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Affiliation(s)
- M P Silva
- Department of Animal Morphology and Physiology, Federal Rural University of Pernambuco, Recife, Pernambuco, Brazil
| | - C G Rodrigues
- Department of Biophysics and Radiobiology, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | - W A Varanda
- Department of Physiology-Faculty of Medicine of Ribeirão Preto, University of São Paulo (Retired), Ribeirão Preto, São Paulo, Brazil
| | - R A Nogueira
- Department of Animal Morphology and Physiology, Federal Rural University of Pernambuco, Recife, Pernambuco, Brazil.
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Akyuz E, Doganyigit Z, Paudel YN, Koklu B, Kaymak E, Villa C, Arulsamy A, Shaikh MF, Devinsky O. Immunoreactivity of Muscarinic Acetylcholine M2 and Serotonin 5-HT2B Receptors, Norepinephrine Transporter and Kir Channels in a Model of Epilepsy. Life (Basel) 2021; 11:life11040276. [PMID: 33810231 PMCID: PMC8066555 DOI: 10.3390/life11040276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/16/2021] [Accepted: 03/23/2021] [Indexed: 11/23/2022] Open
Abstract
Epilepsy is characterized by an imbalance in neurotransmitter activity; an increased excitatory to an inhibitory activity. Acetylcholine (ACh), serotonin, and norepinephrine (NE) may modulate neural activity via several mechanisms, mainly through its receptors/transporter activity and alterations in the extracellular potassium (K+) concentration via K+ ion channels. Seizures may disrupt the regulation of inwardly rectifying K+ (Kir) channels and alter the receptor/transporter activity. However, there are limited data present on the immunoreactivity pattern of these neurotransmitter receptors/transporters and K+ channels in chronic models of epilepsy, which therefore was the aim of this study. Changes in the immunoreactivity of epileptogenesis-related neurotransmitter receptors/transporters (M2, 5-HT2B, and NE transporter) as well as Kir channels (Kir3.1 and Kir6.2) were determined in the cortex, hippocampus and medulla of adult Wistar rats by utilizing a Pentylenetetrazol (PTZ)-kindling chronic epilepsy model. Increased immunoreactivity of the NE transporter, M2, and 5-HT2B receptors was witnessed in the cortex and medulla. While the immunoreactivity of the 5-HT2B receptor was found increased in the cortex and medulla, it was decreased in the hippocampus, with no changes observed in the M2 receptor in this region. Kir3.1 and Kir6.2 staining showed increase immunoreactivity in the cerebral cortex, but channel contrasting findings in the hippocampus and medulla. Our results suggest that seizure kindling may result in significant changes in the neurotransmitter system which may contribute or propagate to future epileptogenesis, brain damage and potentially towards sudden unexpected death in epilepsy (SUDEP). Further studies on the pathogenic role of these changes in neurotransmitter receptors/transporters and K+ channel immunoreactivity may identify newer possible targets to treat seizures or prevent epilepsy-related comorbidities.
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Affiliation(s)
- Enes Akyuz
- Department of Biophysics, Faculty of International Medicine, University of Health Sciences, Istanbul 34668, Turkey
- Correspondence: (E.A.); (O.D.); Tel.: +90-535-7629979 (E.A.); +1-646-558-0803 (O.D.)
| | - Zuleyha Doganyigit
- Department of Histology and Embryology, Faculty of Medicine, Yozgat Bozok University, Yozgat 66100, Turkey; (Z.D.); (E.K.)
| | - Yam Nath Paudel
- Neuropharmacology Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway 47500, Selangor, Malaysia; (Y.N.P.); (A.A.); (M.F.S.)
| | - Betul Koklu
- Faculty of Medicine, Yozgat Bozok University, Yozgat 66100, Turkey;
| | - Emin Kaymak
- Department of Histology and Embryology, Faculty of Medicine, Yozgat Bozok University, Yozgat 66100, Turkey; (Z.D.); (E.K.)
| | - Chiara Villa
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy;
| | - Alina Arulsamy
- Neuropharmacology Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway 47500, Selangor, Malaysia; (Y.N.P.); (A.A.); (M.F.S.)
| | - Mohd. Farooq Shaikh
- Neuropharmacology Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway 47500, Selangor, Malaysia; (Y.N.P.); (A.A.); (M.F.S.)
| | - Orrin Devinsky
- Comprehensive Epilepsy Center, Department of Neurology, NYU Langone School of Medicine, New York, NY 10010, USA
- Correspondence: (E.A.); (O.D.); Tel.: +90-535-7629979 (E.A.); +1-646-558-0803 (O.D.)
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10
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Revisiting the role of neurotransmitters in epilepsy: An updated review. Life Sci 2020; 265:118826. [PMID: 33259863 DOI: 10.1016/j.lfs.2020.118826] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 11/22/2020] [Accepted: 11/24/2020] [Indexed: 12/12/2022]
Abstract
Epilepsy is a neurologicaldisorder characterized by persistent predisposition to recurrent seizurescaused by abnormal neuronal activity in the brain. Epileptic seizures maydevelop due to a relative imbalance of excitatory and inhibitory neurotransmitters. Expressional alterations of receptors and ion channelsactivated by neurotransmitters can lead to epilepsy pathogenesis. AIMS In this updated comprehensive review, we discuss the emerging implication of mutations in neurotransmitter-mediated receptors and ion channels. We aim to provide critical findings of the current literature about the role of neurotransmitters in epilepsy. MATERIALS AND METHODS A comprehensive literature review was conducted to identify and critically evaluate studies analyzing the possible relationship between epilepsy and neurotransmitters. The PubMed database was searched for related research articles. KEY FINDINGS Glutamate and gamma-aminobutyric acid (GABA) are the main neurotransmitters playing a critical role in the pathophysiology of this balance, and irreversible neuronal damage may occur as a result of abnormal changes in these molecules. Acetylcholine (ACh), the main stimulant of the autonomic nervous system, mediates signal transmission through cholinergic and nicotinic receptors. Accumulating evidence indicates that dysfunction of nicotinic ACh receptors, which are widely expressed in hippocampal and cortical neurons, may be significantly implicated in the pathogenesis of epilepsy. The dopamine-norepinephrine-epinephrine cycle activates hormonal and neuronal pathways; serotonin, norepinephrine, histamine, and melatonin can act as both hormones and neurotransmitters. Recent reports have demonstrated that nitric oxide mediates cognitive and memory-related functions via stimulating neuronal transmission. SIGNIFICANCE The elucidation of the role of the main mediators and receptors in epilepsy is crucial for developing new diagnostic and therapeutic approaches.
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Immunotherapy for GRIN2A and GRIN2D-related epileptic encephalopathy. Epilepsy Res 2020; 163:106325. [PMID: 32289570 DOI: 10.1016/j.eplepsyres.2020.106325] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 03/22/2020] [Accepted: 03/26/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND GRIN-related developmental-epileptic encephalopathies are associated with a spectrum of neurodevelopmental disorders, including intellectual disability, epilepsy including continuous spike-and-wave during sleep syndrome (CSWS), or epilepsy-aphasia spectrum phenotypes such as in Landau-Kleffner syndrome. Efficacy of IVIG treatment was recently reported in a patient with LKS related to GRIN2A mutation. AIM AND METHODS We describe the efficacy of Immunotherapy in 5 consecutive patients (4 males, age range 6 months-13 years) with molecularly confirmed GRIN-related epileptic encephalopathy (4 with GRIN2A- related epilepsy-aphasia spectrum/epileptic encephalopathy with CSWS, accompanied by verbal, communicative and behavioural regression, and one patient with GRIN2D - related infantile developmental-epileptic encephalopathy). All patients had global developmental delay/ intellectual disability in various degrees, and were resistant to anticonvulsants, but none of the patients had frequent clinical seizures. All patients received monthly infusion of IVIG 2 g/ kg for 6 months; 2 patients were also treated with high-dose corticosteroids. RESULTS Normalization or near normalization of the EEG was noted in 3 patients, from whom 2 had mild improvement in verbal abilities and communication skills. Perceptual/spatial abilities, as well as executive functions and attention span, remained significantly impaired. CONCLUSION according to this preliminary, open-label study, Immunotherapy may lead to a clinical and electrographic improvement in patients with GRIN-related developmental-epileptic encephalopathies. Further studies to validate the efficacy of immunotherapy and the potential role of autoimmunity in GRIN-related disorders are needed.
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Samudra N, Zacharias T, Plitt A, Lega B, Pan E. Seizures in glioma patients: An overview of incidence, etiology, and therapies. J Neurol Sci 2019; 404:80-85. [PMID: 31352293 DOI: 10.1016/j.jns.2019.07.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/24/2019] [Accepted: 07/18/2019] [Indexed: 12/19/2022]
Abstract
Gliomas are fatal brain tumors, and even low-grade gliomas (LGGs) have an average survival of less than a decade. Seizures are a common presentation of gliomas, particularly LGGs, and substantially impact quality of life. Glioma-related seizures differ from other focal epilepsies in their pathogenesis and in the likelihood of refractory epilepsy. We review factors that predict seizure activity and response to treatment, optimal pharmacologic and surgical management of glioma-related epilepsy, and the benefit of using newer anti-seizure medications in patients with gliomas. As surgery is so often beneficial with seizure reduction, we discuss oncologic and epilepsy surgery perspectives. Treatment of gliomas has the potential to ameliorate seizures and increase rates of seizure freedom. Prospective, well-powered studies are needed to provide more definitive answers for practitioners taking care of glioma patients with seizures.
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Affiliation(s)
- Niyatee Samudra
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Tresa Zacharias
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Aaron Plitt
- Department of Neurosurgery, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Bradley Lega
- Department of Neurosurgery, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Edward Pan
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA.
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González OC, Krishnan GP, Timofeev I, Bazhenov M. Ionic and synaptic mechanisms of seizure generation and epileptogenesis. Neurobiol Dis 2019; 130:104485. [PMID: 31150792 DOI: 10.1016/j.nbd.2019.104485] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/23/2019] [Accepted: 05/27/2019] [Indexed: 01/09/2023] Open
Abstract
The biophysical mechanisms underlying epileptogenesis and the generation of seizures remain to be better understood. Among many factors triggering epileptogenesis are traumatic brain injury breaking normal synaptic homeostasis and genetic mutations disrupting ionic concentration homeostasis. Impairments in these mechanisms, as seen in various brain diseases, may push the brain network to a pathological state characterized by increased susceptibility to unprovoked seizures. Here, we review recent computational studies exploring the roles of ionic concentration dynamics in the generation, maintenance, and termination of seizures. We further discuss how ionic and synaptic homeostatic mechanisms may give rise to conditions which prime brain networks to exhibit recurrent spontaneous seizures and epilepsy.
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Affiliation(s)
- Oscar C González
- Neurosciences Graduate Program, University of California, San Diego, CA 92093, United States of America; Department of Medicine, University of California, San Diego, CA 92093, United States of America
| | - Giri P Krishnan
- Department of Medicine, University of California, San Diego, CA 92093, United States of America
| | - Igor Timofeev
- Centre de recherche de l'Institut universitaire en santé mentale de Québec (CRIUSMQ), 2601 de la Canardière, Québec, QC, Canada; Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada
| | - Maxim Bazhenov
- Neurosciences Graduate Program, University of California, San Diego, CA 92093, United States of America; Department of Medicine, University of California, San Diego, CA 92093, United States of America.
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Myers TL, Gonzalez OC, Stein JB, Bazhenov M. Characterizing Concentration-Dependent Neural Dynamics of 4-Aminopyridine-Induced Epileptiform Activity. ACTA ACUST UNITED AC 2018; 4. [PMID: 30450487 PMCID: PMC6234984 DOI: 10.4172/2472-0895.1000128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Epilepsy remains one of the most common neurological disorders. In patients, it is characterized by unprovoked, spontaneous, and recurrent seizures or ictal events. Typically, inter-ictal events or large bouts of population level activity can be measured between seizures and are generally asymptomatic. Decades of research have focused on understanding the mechanisms leading to the development of seizure-like activity using various pro-convulsive pharmacological agents, including 4-aimnopyridine (4AP). However, the lack of consistency in the concentrations used for studying 4AP-induced epileptiform activity in animal models may give rise to differences in results and interpretation thereof. Indeed, the range of 4AP concentration in both in vivo and in vitro studies varies from 3 μM to 40 mM. Here, we explored the effects of various 4AP concentrations on the development and characteristics of hippocampal epileptiform activity in acute mouse brain slices of either sex. Using multi-electrode array recordings, we show that 4AP induces hippocampal epileptiform activity for a broad range of concentrations. The frequency component and the spatiotemporal patterns of the epileptiform activity revealed a dose-dependent response. Finally, in the presence of 4AP, reduction of KCC2 co-transporter activity by KCC2 antagonist VU0240551 prevented the manifestation of the frequency component differences between different concentrations of 4AP. Overall, the study predicts that different concentrations of 4AP can result in the different mechanisms behind hippocampal epileptiform activity, of which some are dependent on the KCC2 co-transporter function.
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Affiliation(s)
- Timothy L Myers
- Neuroscience Graduate Program, University of California, Riverside, California, United States of America.,Department of Cell Biology and Neuroscience, University of California, Riverside, California, United States of America
| | - Oscar C Gonzalez
- Department of Medicine, University of California, San Diego, California, United States of America.,Neuroscience Graduate Program, University of California, San Diego, California, United States of America
| | - Jacob B Stein
- Department of Cell Biology and Neuroscience, University of California, Riverside, California, United States of America
| | - Maxim Bazhenov
- Department of Medicine, University of California, San Diego, California, United States of America
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van den Ende T, Sharifi S, van der Salm SMA, van Rootselaar AF. Familial Cortical Myoclonic Tremor and Epilepsy, an Enigmatic Disorder: From Phenotypes to Pathophysiology and Genetics. A Systematic Review. Tremor Other Hyperkinet Mov (N Y) 2018; 8:503. [PMID: 29416935 PMCID: PMC5801339 DOI: 10.7916/d85155wj] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 01/02/2018] [Indexed: 02/06/2023] Open
Abstract
Background Autosomal dominant familial cortical myoclonic tremor and epilepsy (FCMTE) is characterized by distal tremulous myoclonus, generalized seizures, and signs of cortical reflex myoclonus. FCMTE has been described in over 100 pedigrees worldwide, under several different names and acronyms. Pathological changes have been located in the cerebellum. This systematic review discusses the clinical spectrum, treatment, pathophysiology, and genetic findings. Methods We carried out a PubMed search, using a combination of the following search terms: cortical tremor, myoclonus, epilepsy, benign course, adult onset, familial, and autosomal dominant; this resulted in a total of 77 studies (761 patients; 126 pedigrees) fulfilling the inclusion and exclusion criteria. Results Phenotypic differences across pedigrees exist, possibly related to underlying genetic differences. A "benign" phenotype has been described in several Japanese families and pedigrees linked to 8q (FCMTE1). French patients (5p linkage; FCMTE3) exhibit more severe progression, and in Japanese/Chinese pedigrees (with unknown linkage) anticipation has been suggested. Preferred treatment is with valproate (mind teratogenicity), levetiracetam, and/or clonazepam. Several genes have been identified, which differ in potential pathogenicity. Discussion Based on the core features (above), the syndrome can be considered a distinct clinical entity. Clinical features may also include proximal myoclonus and mild progression with aging. Valproate or levetiracetam, with or without clonazepam, reduces symptoms. FCMTE is a heterogeneous disorder, and likely to include a variety of different conditions with mutations of different genes. Distinct phenotypic traits might reflect different genetic mutations. Genes involved in Purkinje cell outgrowth or those encoding for ion channels or neurotransmitters seem good candidate genes.
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Affiliation(s)
- Tom van den Ende
- Department of Neurology and Clinical Neurophysiology, Amsterdam Neuroscience, Academic Medical Center, Amsterdam, The Netherlands
| | - Sarvi Sharifi
- Department of Neurology and Clinical Neurophysiology, Amsterdam Neuroscience, Academic Medical Center, Amsterdam, The Netherlands
| | - Sandra M. A. van der Salm
- Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center, Utrecht, The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Zwolle, The Netherlands
| | - Anne-Fleur van Rootselaar
- Department of Neurology and Clinical Neurophysiology, Amsterdam Neuroscience, Academic Medical Center, Amsterdam, The Netherlands
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González OC, Shiri Z, Krishnan GP, Myers TL, Williams S, Avoli M, Bazhenov M. Role of KCC2-dependent potassium efflux in 4-Aminopyridine-induced Epileptiform synchronization. Neurobiol Dis 2018; 109:137-147. [PMID: 29045814 PMCID: PMC5710807 DOI: 10.1016/j.nbd.2017.10.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/09/2017] [Accepted: 10/13/2017] [Indexed: 01/23/2023] Open
Abstract
A balance between excitation and inhibition is necessary to maintain stable brain network dynamics. Traditionally, seizure activity is believed to arise from the breakdown of this delicate balance in favor of excitation with loss of inhibition. Surprisingly, recent experimental evidence suggests that this conventional view may be limited, and that inhibition plays a prominent role in the development of epileptiform synchronization. Here, we explored the role of the KCC2 co-transporter in the onset of inhibitory network-induced seizures. Our experiments in acute mouse brain slices, of either sex, revealed that optogenetic stimulation of either parvalbumin- or somatostatin-expressing interneurons induced ictal discharges in rodent entorhinal cortex during 4-aminopyridine application. These data point to a proconvulsive role of GABAA receptor signaling that is independent of the inhibitory input location (i.e., dendritic vs. somatic). We developed a biophysically realistic network model implementing dynamics of ion concentrations to explore the mechanisms leading to inhibitory network-induced seizures. In agreement with experimental results, we found that stimulation of the inhibitory interneurons induced seizure-like activity in a network with reduced potassium A-current. Our model predicts that interneuron stimulation triggered an increase of interneuron firing, which was accompanied by an increase in the intracellular chloride concentration and a subsequent KCC2-dependent gradual accumulation of the extracellular potassium promoting epileptiform ictal activity. When the KCC2 activity was reduced, stimulation of the interneurons was no longer able to induce ictal events. Overall, our study provides evidence for a proconvulsive role of GABAA receptor signaling that depends on the involvement of the KCC2 co-transporter.
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Affiliation(s)
- Oscar C González
- Neurosciences Graduate Program, University of California, San Diego, CA, United States; Department of Medicine, University of California, San Diego, CA, United States
| | - Zahra Shiri
- Montreal Neurological Institute, McGill University, Montréal, H4H 1R3 Québec, Canada
| | - Giri P Krishnan
- Department of Medicine, University of California, San Diego, CA, United States
| | - Timothy L Myers
- Neuroscience Graduate Program, University of California, Riverside, CA, United States; Department of Cell Biology and Neuroscience, University of California, Riverside, CA, United States
| | - Sylvain Williams
- Douglas Mental Health University Institute, McGill University, Montréal, H4H 1R3 Québec, Canada
| | - Massimo Avoli
- Montreal Neurological Institute, McGill University, Montréal, H4H 1R3 Québec, Canada; Department of Physiology, McGill University, Montréal, H4H 1R3 Québec, Canada
| | - Maxim Bazhenov
- Neurosciences Graduate Program, University of California, San Diego, CA, United States; Department of Medicine, University of California, San Diego, CA, United States.
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