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Sosunov AA, McKhann Ii G, Tang G, Goldman JE. Cytoplasmic vacuolization and ectopic formation of perineuronal nets are characteristic pathologies of cytomegalic neurons in tuberous sclerosis. J Neuropathol Exp Neurol 2024:nlae079. [PMID: 39024216 DOI: 10.1093/jnen/nlae079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024] Open
Abstract
Cytomegalic neurons, characterized by increased size and a hyperactive mechanistic target of rapamycin complex 1 (mTORC1), are pathognomonic for tuberous sclerosis complex (TSC). To model these neurons, we recently generated a murine Tsc1 conditional knockout model in which Tsc1 deletion in late embryonic radial glia results in neuronal hypertrophy of a subset of isocortical pyramidal neurons. In the current study, we compared the cellular pathology of these cytomegalic neurons to those of the enlarged neurons in human cortical tubers. Neurons from the mice showed unique features, such as cytoplasmic vacuoles associated with Golgi complexes and the ectopic formation of perineuronal nets (PNNs), a feature of inhibitory neurons, rarely present in excitatory cortical neurons. The membranes of these vacuoles were enriched for the plasma membrane proteins CD44, KCC2, and Na+/K+ ATPase, suggesting deficits in Golgi membrane trafficking. These aberrant features in the mouse appeared only after the onset of seizures, probably due to the prolonged seizure activity in the context of constitutive mTORC1 activation. Similar PNNs and cytoplasmic vacuoles were present in the cytomegalic neurons of human cortical tubers. Our findings reveal novel pathological features of Golgi complexes and PNNs in the cytomegalic neurons in TSC.
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Affiliation(s)
- Alexander A Sosunov
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY, United States
| | - Guy McKhann Ii
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY, United States
| | - Guomei Tang
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
| | - James E Goldman
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York, NY, United States
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2
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Juknevičienė M, Balnytė I, Valančiūtė A, Alonso MM, Preikšaitis A, Sužiedėlis K, Stakišaitis D. Differential Impact of Valproic Acid on SLC5A8, SLC12A2, SLC12A5, CDH1, and CDH2 Expression in Adult Glioblastoma Cells. Biomedicines 2024; 12:1416. [PMID: 39061990 PMCID: PMC11274075 DOI: 10.3390/biomedicines12071416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 06/13/2024] [Accepted: 06/22/2024] [Indexed: 07/28/2024] Open
Abstract
Valproic acid (VPA) has anticancer, anti-inflammatory, and epigenetic effects. The study aimed to determine the expression of carcinogenesis-related SLC5A8, SLC12A2, SLC12A5, CDH1, and CDH2 in adult glioblastoma U87 MG and T98G cells and the effects of 0.5 mM, 0.75 mM, and 1.5 mM doses of VPA. RNA gene expression was determined by RT-PCR. GAPDH was used as a control. U87 and T98G control cells do not express SLC5A8 or CDH1. SLC12A5 was expressed in U87 control but not in T98G control cells. The SLC12A2 expression in the U87 control was significantly lower than in the T98G control. T98G control cells showed significantly higher CDH2 expression than U87 control cells. VPA treatment did not affect SLC12A2 expression in U87 cells, whereas treatment dose-dependently increased SLC12A2 expression in T98G cells. Treatment with 1.5 mM VPA induced SLC5A8 expression in U87 cells, while treatment of T98G cells with VPA did not affect SLC5A8 expression. Treatment of U87 cells with VPA significantly increased SLC12A5 expression. VPA increases CDH1 expression depending on the VPA dose. CDH2 expression was significantly increased only in the U87 1.5 mM VPA group. Tested VPA doses significantly increased CDH2 expression in T98G cells. When approaching treatment tactics, assessing the cell's sensitivity to the agent is essential.
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Affiliation(s)
- Milda Juknevičienė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (M.J.); (I.B.); (A.V.)
| | - Ingrida Balnytė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (M.J.); (I.B.); (A.V.)
| | - Angelija Valančiūtė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (M.J.); (I.B.); (A.V.)
| | - Marta Marija Alonso
- Department of Pediatrics, Clínica Universidad de Navarra, University of Navarra, 31008 Pamplona, Spain;
| | - Aidanas Preikšaitis
- Centre of Neurosurgery, Clinic of Neurology and Neurosurgery, Faculty of Medicine, Vilnius University, 03101 Vilnius, Lithuania;
| | - Kęstutis Sužiedėlis
- Laboratory of Molecular Oncology, National Cancer Institute, 08660 Vilnius, Lithuania;
| | - Donatas Stakišaitis
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (M.J.); (I.B.); (A.V.)
- Laboratory of Molecular Oncology, National Cancer Institute, 08660 Vilnius, Lithuania;
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3
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Cases-Cunillera S, Friker LL, Müller P, Becker AJ, Gielen GH. From bedside to bench: New insights in epilepsy-associated tumors based on recent classification updates and animal models on brain tumor networks. Mol Oncol 2024. [PMID: 38899375 DOI: 10.1002/1878-0261.13680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 12/28/2023] [Accepted: 05/29/2024] [Indexed: 06/21/2024] Open
Abstract
Low-grade neuroepithelial tumors (LGNTs), particularly those with glioneuronal histology, are highly associated with pharmacoresistant epilepsy. Increasing research focused on these neoplastic lesions did not translate into drug discovery; and anticonvulsant or antitumor therapies are not available yet. During the last years, animal modeling has improved, thereby leading to the possibility of generating brain tumors in mice mimicking crucial genetic, molecular and immunohistological features. Among them, intraventricular in utero electroporation (IUE) has been proven to be a valuable tool for the generation of animal models for LGNTs allowing endogenous tumor growth within the mouse brain parenchyma. Epileptogenicity is mostly determined by the slow-growing patterns of these tumors, thus mirroring intrinsic interactions between tumor cells and surrounding neurons is crucial to investigate the mechanisms underlying convulsive activity. In this review, we provide an updated classification of the human LGNT and summarize the most recent data from human and animal models, with a focus on the crosstalk between brain tumors and neuronal function.
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Affiliation(s)
- Silvia Cases-Cunillera
- INSERM U1266, Neuronal Signaling in Epilepsy and Glioma, Institute of Psychiatry and Neuroscience of Paris (IPNP), Université Paris Cité, Paris, France
- Section for Translational Epilepsy Research, Institute of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Lea L Friker
- Institute of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Philipp Müller
- Section for Translational Epilepsy Research, Institute of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Albert J Becker
- Section for Translational Epilepsy Research, Institute of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Gerrit H Gielen
- Institute of Neuropathology, University Hospital Bonn, Bonn, Germany
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4
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Scheper M, Sørensen FNF, Ruffolo G, Gaeta A, Lissner LJ, Anink JJ, Korshunova I, Jansen FE, Riney K, van Hecke W, Mühlebner A, Khodosevich K, Schubert D, Palma E, Mills JD, Aronica E. Impaired GABAergic regulation and developmental immaturity in interneurons derived from the medial ganglionic eminence in the tuberous sclerosis complex. Acta Neuropathol 2024; 147:80. [PMID: 38714540 PMCID: PMC11076412 DOI: 10.1007/s00401-024-02737-7] [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: 03/14/2024] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 05/10/2024]
Abstract
GABAergic interneurons play a critical role in maintaining neural circuit balance, excitation-inhibition regulation, and cognitive function modulation. In tuberous sclerosis complex (TSC), GABAergic neuron dysfunction contributes to disrupted network activity and associated neurological symptoms, assumingly in a cell type-specific manner. This GABAergic centric study focuses on identifying specific interneuron subpopulations within TSC, emphasizing the unique characteristics of medial ganglionic eminence (MGE)- and caudal ganglionic eminence (CGE)-derived interneurons. Using single-nuclei RNA sequencing in TSC patient material, we identify somatostatin-expressing (SST+) interneurons as a unique and immature subpopulation in TSC. The disrupted maturation of SST+ interneurons may undergo an incomplete switch from excitatory to inhibitory GABAergic signaling during development, resulting in reduced inhibitory properties. Notably, this study reveals markers of immaturity specifically in SST+ interneurons, including an abnormal NKCC1/KCC2 ratio, indicating an imbalance in chloride homeostasis crucial for the postsynaptic consequences of GABAergic signaling as well as the downregulation of GABAA receptor subunits, GABRA1, and upregulation of GABRA2. Further exploration of SST+ interneurons revealed altered localization patterns of SST+ interneurons in TSC brain tissue, concentrated in deeper cortical layers, possibly linked to cortical dyslamination. In the epilepsy context, our research underscores the diverse cell type-specific roles of GABAergic interneurons in shaping seizures, advocating for precise therapeutic considerations. Moreover, this study illuminates the potential contribution of SST+ interneurons to TSC pathophysiology, offering insights for targeted therapeutic interventions.
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Affiliation(s)
- Mirte Scheper
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam UMC Location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands.
| | - Frederik N F Sørensen
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Gabriele Ruffolo
- Department of Physiology and Pharmacology, University of Rome Sapienza, 00185, Rome, Italy
- IRCCS San Raffaele Roma, 00163, Rome, Italy
| | - Alessandro Gaeta
- Department of Physiology and Pharmacology, University of Rome Sapienza, 00185, Rome, Italy
| | - Lilian J Lissner
- Department of Physiology and Pharmacology, University of Rome Sapienza, 00185, Rome, Italy
| | - Jasper J Anink
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam UMC Location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands
| | - Irina Korshunova
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Floor E Jansen
- Department of Child Neurology, Brain Center University Medical Center, Member of ERN EpiCare, 3584 BA, Utrecht, The Netherlands
| | - Kate Riney
- Faculty of Medicine, The University of Queensland, St Lucia, QLD, 4067, Australia
- Neurosciences Unit, Queensland Children's Hospital, South Brisbane, QLD, 4101, Australia
| | - Wim van Hecke
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Angelika Mühlebner
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Konstantin Khodosevich
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Dirk Schubert
- Department of Cognitive Neurosciences, Radboudumc, Donders Institute for Brain Cognition and Behaviour, 6525 HR, Nijmegen, The Netherlands
| | - Eleonora Palma
- Department of Physiology and Pharmacology, University of Rome Sapienza, 00185, Rome, Italy
- IRCCS San Raffaele Roma, 00163, Rome, Italy
| | - James D Mills
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam UMC Location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands
- UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
- Chalfont Centre for Epilepsy, Bucks, SL9 0RJ, UK
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam UMC Location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
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Du Y, Li R, Fu D, Zhang B, Cui A, Shao Y, Lai Z, Chen R, Chen B, Wang Z, Zhang W, Chu L. Multi-omics technologies and molecular biomarkers in brain tumor-related epilepsy. CNS Neurosci Ther 2024; 30:e14717. [PMID: 38641945 PMCID: PMC11031674 DOI: 10.1111/cns.14717] [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: 11/17/2023] [Revised: 03/04/2024] [Accepted: 03/29/2024] [Indexed: 04/21/2024] Open
Abstract
BACKGROUND Brain tumors are one of the leading causes of epilepsy, and brain tumor-related epilepsy (BTRE) is recognized as the major cause of intractable epilepsy, resulting in huge treatment cost and burden to patients, their families, and society. Although optimal treatment regimens are available, the majority of patients with BTRE show poor resolution of symptoms. BTRE has a very complex and multifactorial etiology, which includes several influencing factors such as genetic and molecular biomarkers. Advances in multi-omics technologies have enabled to elucidate the pathophysiological mechanisms and related biomarkers of BTRE. Here, we reviewed multi-omics technology-based research studies on BTRE published in the last few decades and discussed the present status, development, opportunities, challenges, and prospects in treating BTRE. METHODS First, we provided a general review of epilepsy, BTRE, and multi-omics techniques. Next, we described the specific multi-omics (including genomics, transcriptomics, epigenomics, proteomics, and metabolomics) techniques and related molecular biomarkers for BTRE. We then presented the associated pathogenetic mechanisms of BTRE. Finally, we discussed the development and application of novel omics techniques for diagnosing and treating BTRE. RESULTS Genomics studies have shown that the BRAF gene plays a role in BTRE development. Furthermore, the BRAF V600E variant was found to induce epileptogenesis in the neuronal cell lineage and tumorigenesis in the glial cell lineage. Several genomics studies have linked IDH variants with glioma-related epilepsy, and the overproduction of D2HG is considered to play a role in neuronal excitation that leads to seizure occurrence. The high expression level of Forkhead Box O4 (FOXO4) was associated with a reduced risk of epilepsy occurrence. In transcriptomics studies, VLGR1 was noted as a biomarker of epileptic onset in patients. Several miRNAs such as miR-128 and miRNA-196b participate in BTRE development. miR-128 might be negatively associated with the possibility of tumor-related epilepsy development. The lncRNA UBE2R2-AS1 inhibits the growth and invasion of glioma cells and promotes apoptosis. Quantitative proteomics has been used to determine dynamic changes of protein acetylation in epileptic and non-epileptic gliomas. In another proteomics study, a high expression of AQP-4 was detected in the brain of GBM patients with seizures. By using quantitative RT-PCR and immunohistochemistry assay, a study revealed that patients with astrocytomas and oligoastrocytomas showed high BCL2A1 expression and poor seizure control. By performing immunohistochemistry, several studies have reported the relationship between D2HG overproduction and seizure occurrence. Ki-67 overexpression in WHO grade II gliomas was found to be associated with poor postoperative seizure control. According to metabolomics research, the PI3K/AKT/mTOR pathway is associated with the development of glioma-related epileptogenesis. Another metabolomics study found that SV2A, P-gb, and CAD65/67 have the potential to function as biomarkers for BTRE. CONCLUSIONS Based on the synthesized information, this review provided new research perspectives and insights into the early diagnosis, etiological factors, and personalized treatment of BTRE.
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Affiliation(s)
- Yaoqiang Du
- Laboratory Medicine Center, Department of Transfusion MedicineZhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical CollegeHangzhouChina
- School of Basic Medical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Rusong Li
- The Second School of Clinical MedicineZhejiang Chinese Medical UniversityHangzhouChina
| | - Danqing Fu
- School of Basic Medical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Biqin Zhang
- Cancer Center, Department of HematologyZhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical CollegeHangzhouChina
| | - Ailin Cui
- Cancer Center, Department of Ultrasound MedicineZhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical CollegeHangzhouChina
| | - Yutian Shao
- Zhejiang BioAsia Life Science InstitutePinghuChina
| | - Zeyu Lai
- The Second School of Clinical MedicineZhejiang Chinese Medical UniversityHangzhouChina
| | - Rongrong Chen
- School of Clinical MedicineHangzhou Normal UniversityHangzhouChina
| | - Bingyu Chen
- Laboratory Medicine Center, Department of Transfusion MedicineZhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical CollegeHangzhouChina
| | - Zhen Wang
- Laboratory Medicine Center, Department of Transfusion MedicineZhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical CollegeHangzhouChina
| | - Wei Zhang
- The Second School of Clinical MedicineZhejiang Chinese Medical UniversityHangzhouChina
| | - Lisheng Chu
- School of Basic Medical SciencesZhejiang Chinese Medical UniversityHangzhouChina
- Department of PhysiologyZhejiang Chinese Medical UniversityHangzhouChina
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McMoneagle E, Zhou J, Zhang S, Huang W, Josiah SS, Ding K, Wang Y, Zhang J. Neuronal K +-Cl - cotransporter KCC2 as a promising drug target for epilepsy treatment. Acta Pharmacol Sin 2024; 45:1-22. [PMID: 37704745 PMCID: PMC10770335 DOI: 10.1038/s41401-023-01149-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/02/2023] [Indexed: 09/14/2023] Open
Abstract
Epilepsy is a prevalent neurological disorder characterized by unprovoked seizures. γ-Aminobutyric acid (GABA) serves as the primary fast inhibitory neurotransmitter in the brain, and GABA binding to the GABAA receptor (GABAAR) regulates Cl- and bicarbonate (HCO3-) influx or efflux through the channel pore, leading to GABAergic inhibition or excitation, respectively. The neuron-specific K+-Cl- cotransporter 2 (KCC2) is essential for maintaining a low intracellular Cl- concentration, ensuring GABAAR-mediated inhibition. Impaired KCC2 function results in GABAergic excitation associated with epileptic activity. Loss-of-function mutations and altered expression of KCC2 lead to elevated [Cl-]i and compromised synaptic inhibition, contributing to epilepsy pathogenesis in human patients. KCC2 antagonism studies demonstrate the necessity of limiting neuronal hyperexcitability within the brain, as reduced KCC2 functioning leads to seizure activity. Strategies focusing on direct (enhancing KCC2 activation) and indirect KCC2 modulation (altering KCC2 phosphorylation and transcription) have proven effective in attenuating seizure severity and exhibiting anti-convulsant properties. These findings highlight KCC2 as a promising therapeutic target for treating epilepsy. Recent advances in understanding KCC2 regulatory mechanisms, particularly via signaling pathways such as WNK, PKC, BDNF, and its receptor TrkB, have led to the discovery of novel small molecules that modulate KCC2. Inhibiting WNK kinase or utilizing newly discovered KCC2 agonists has demonstrated KCC2 activation and seizure attenuation in animal models. This review discusses the role of KCC2 in epilepsy and evaluates its potential as a drug target for epilepsy treatment by exploring various strategies to regulate KCC2 activity.
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Affiliation(s)
- Erin McMoneagle
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK
| | - Jin Zhou
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Shiyao Zhang
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital Xiamen University, School of Medicine, Xiamen University, Xiang'an Nan Lu, Xiamen, 361102, China
| | - Weixue Huang
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Sunday Solomon Josiah
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK
| | - Ke Ding
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China.
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK.
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital Xiamen University, School of Medicine, Xiamen University, Xiang'an Nan Lu, Xiamen, 361102, China.
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China.
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Abstract
Rett syndrome is a neurodevelopmental disorder caused by loss-of-function mutations in the methyl-CpG binding protein-2 (MeCP2) gene that is characterized by epilepsy, intellectual disability, autistic features, speech deficits, and sleep and breathing abnormalities. Neurologically, patients with all three disorders display microcephaly, aberrant dendritic morphology, reduced spine density, and an imbalance of excitatory/inhibitory signaling. Loss-of-function mutations in the cyclin-dependent kinase-like 5 (CDKL5) and FOXG1 genes also cause similar behavioral and neurobiological defects and were referred to as congenital or variant Rett syndrome. The relatively recent realization that CDKL5 deficiency disorder (CDD), FOXG1 syndrome, and Rett syndrome are distinct neurodevelopmental disorders with some distinctive features have resulted in separate focus being placed on each disorder with the assumption that distinct molecular mechanisms underlie their pathogenesis. However, given that many of the core symptoms and neurological features are shared, it is likely that the disorders share some critical molecular underpinnings. This review discusses the possibility that deregulation of common molecules in neurons and astrocytes plays a central role in key behavioral and neurological abnormalities in all three disorders. These include KCC2, a chloride transporter, vGlut1, a vesicular glutamate transporter, GluD1, an orphan-glutamate receptor subunit, and PSD-95, a postsynaptic scaffolding protein. We propose that reduced expression or activity of KCC2, vGlut1, PSD-95, and AKT, along with increased expression of GluD1, is involved in the excitatory/inhibitory that represents a key aspect in all three disorders. In addition, astrocyte-derived brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1), and inflammatory cytokines likely affect the expression and functioning of these molecules resulting in disease-associated abnormalities.
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Affiliation(s)
- Santosh R D’Mello
- Department of Biological Sciences, Louisiana State University Shreveport, Shreveport, LA 71104, USA
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8
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Tescarollo FC, Valdivia D, Chen S, Sun H. Unilateral optogenetic kindling of hippocampus leads to more severe impairments of the inhibitory signaling in the contralateral hippocampus. Front Mol Neurosci 2023; 16:1268311. [PMID: 37942301 PMCID: PMC10627882 DOI: 10.3389/fnmol.2023.1268311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/20/2023] [Indexed: 11/10/2023] Open
Abstract
The kindling model has been used extensively by researchers to study the neurobiology of temporal lobe epilepsy (TLE) due to its capacity to induce intensification of seizures by the progressive recruitment of additional neuronal clusters into epileptogenic networks. We applied repetitive focal optogenetic activation of putative excitatory neurons in the dorsal CA1 area of the hippocampus of mice to investigate the role of inhibitory signaling during this process. This experimental protocol resulted in a kindling phenotype that was maintained for 2 weeks after the animals were fully kindled. As a result of the different phases of optogenetic kindling (OpK), key inhibitory signaling elements, such as KCC2 and NKCC1, exhibited distinct temporal and spatial dynamics of regulation. These alterations in protein expression were related to the distinct pattern of ictal activity propagation through the different hippocampal sublayers. Our results suggest the KCC2 disruption in the contralateral hippocampus of fully kindled animals progressively facilitated the creation of pathological pathways for seizure propagation through the hippocampal network. Upon completion of kindling, we observed animals that were restimulated after a rest period of 14-day showed, besides a persistent KCC2 downregulation, an NKCC1 upregulation in the bilateral dentate gyrus and hippocampus-wide loss of parvalbumin-positive interneurons. These alterations observed in the chronic phase of OpK suggest that the hippocampus of rekindled animals continued to undergo self-modifications during the rest period. The changes resulting from this period suggest the possibility of the development of a mirror focus on the hippocampus contralateral to the site of optical stimulations. Our results offer perspectives for preventing the recruitment and conversion of healthy neuronal networks into epileptogenic ones among patients with epilepsy.
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Affiliation(s)
| | | | | | - Hai Sun
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, United States
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Bod R, Tóth K, Essam N, Tóth EZ, Erõss L, Entz L, Bagó AG, Fabó D, Ulbert I, Wittner L. Synaptic alterations and neuronal firing in human epileptic neocortical excitatory networks. Front Synaptic Neurosci 2023; 15:1233569. [PMID: 37635750 PMCID: PMC10450510 DOI: 10.3389/fnsyn.2023.1233569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 07/25/2023] [Indexed: 08/29/2023] Open
Abstract
Epilepsy is a prevalent neurological condition, with underlying neuronal mechanisms involving hyperexcitability and hypersynchrony. Imbalance between excitatory and inhibitory circuits, as well as histological reorganization are relatively well-documented in animal models or even in the human hippocampus, but less is known about human neocortical epileptic activity. Our knowledge about changes in the excitatory signaling is especially scarce, compared to that about the inhibitory cell population. This study investigated the firing properties of single neurons in the human neocortex in vitro, during pharmacological blockade of glutamate receptors, and additionally evaluated anatomical changes in the excitatory circuit in tissue samples from epileptic and non-epileptic patients. Both epileptic and non-epileptic tissues exhibited spontaneous population activity (SPA), NMDA receptor antagonization reduced SPA recurrence only in epileptic tissue, whereas further blockade of AMPA/kainate receptors reversibly abolished SPA emergence regardless of epilepsy. Firing rates did not significantly change in excitatory principal cells and inhibitory interneurons during pharmacological experiments. Granular layer (L4) neurons showed an increased firing rate in epileptic compared to non-epileptic tissue. The burstiness of neurons remained unchanged, except for that of inhibitory cells in epileptic recordings, which decreased during blockade of glutamate receptors. Crosscorrelograms computed from single neuron discharge revealed both mono- and polysynaptic connections, particularly involving intrinsically bursting principal cells. Histological investigations found similar densities of SMI-32-immunopositive long-range projecting pyramidal cells in both groups, and shorter excitatory synaptic active zones with a higher proportion of perforated synapses in the epileptic group. These findings provide insights into epileptic modifications from the perspective of the excitatory system and highlight discrete alterations in firing patterns and synaptic structure. Our data suggest that NMDA-dependent glutamatergic signaling, as well as the excitatory synaptic machinery are perturbed in epilepsy, which might contribute to epileptic activity in the human neocortex.
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Affiliation(s)
- Réka Bod
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
- Semmelweis University Doctoral School, Budapest, Hungary
| | - Kinga Tóth
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
| | - Nour Essam
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
| | - Estilla Zsófia Tóth
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
- Semmelweis University Doctoral School, Budapest, Hungary
| | - Loránd Erõss
- National Institute of Mental Health, Neurology and Neurosurgery, Budapest, Hungary
| | - László Entz
- National Institute of Mental Health, Neurology and Neurosurgery, Budapest, Hungary
| | - Attila G. Bagó
- National Institute of Mental Health, Neurology and Neurosurgery, Budapest, Hungary
| | - Dániel Fabó
- National Institute of Mental Health, Neurology and Neurosurgery, Budapest, Hungary
| | - István Ulbert
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
- Semmelweis University Doctoral School, Budapest, Hungary
- National Institute of Mental Health, Neurology and Neurosurgery, Budapest, Hungary
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Lucia Wittner
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Eötvös Loránd Research Network, Budapest, Hungary
- Semmelweis University Doctoral School, Budapest, Hungary
- National Institute of Mental Health, Neurology and Neurosurgery, Budapest, Hungary
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10
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Bonet-Fernández JM, Tranque P, Aroca-Aguilar JD, Muñoz LJ, López DE, Escribano J, de Cabo C. Seizures regulate the cation-Cl - cotransporter NKCC1 in a hamster model of epilepsy: implications for GABA neurotransmission. Front Neurol 2023; 14:1207616. [PMID: 37448751 PMCID: PMC10338185 DOI: 10.3389/fneur.2023.1207616] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 06/05/2023] [Indexed: 07/15/2023] Open
Abstract
Background The balance between the activity of the Na+/K+/Cl- cotransporter (NKCC1) that introduces Cl- into the cell and the K+/Cl- cotransporter (KCC2) that transports Cl- outside the cell is critical in determining the inhibitory or excitatory outcome of GABA release. Mounting evidence suggests that the impairment of GABAergic inhibitory neurotransmission plays a crucial role in the pathophysiology of epilepsy, both in patients and animal models. Previous studies indicate that decreased KCC2 expression is linked to audiogenic seizures in GASH/Sal hamsters, highlighting that Cl- imbalance can cause neuronal hyperexcitability. In this study, we aimed to investigate whether the Na+/K+/Cl- cotransporter NKCC1 is also affected by audiogenic seizures and could, therefore, play a role in neuronal hyperexcitability within the GASH/Sal epilepsy model. Methods NKCC1 protein expression in both the GASH/Sal strain and wild type hamsters was analyzed by immunohistochemistry and Western blotting techniques. Brain regions examined included cortex, hippocampus, hypothalamus, inferior colliculus and pons-medulla oblongata, which were evaluated both at rest and after sound-inducing seizures in GASH/Sal hamsters. A complementary analysis of NKCC1 gene slc12a2 expression was conducted by real-time PCR. Finally, protein and mRNA levels of glutamate decarboxylase GAD67 were measured as an indicator of GABA release. Results The induction of seizures caused significant changes in NKCC1 expression in epileptic GASH/Sal hamsters, despite the similar brain expression pattern of NKCC1 in GASH/Sal and wild type hamsters in the absence of seizures. Interestingly, the regulation of brain NKCC1 by seizures demonstrated regional specificity, as protein levels exclusively increased in the hippocampus and hypothalamus. Complementary real-time PCR analysis revealed that NKCC1 regulation was post-transcriptional only in the hypothalamus. In addition, seizures also modulated GAD67 mRNA levels in a brain region-specific manner. The increased GAD67 expression in the hippocampus and hypothalamus of the epileptic hamster brain suggests that NKCC1 upregulation overlaps with GABA release in these regions during seizures. Conclusions Our results indicate that seizure induction causes dysregulation of NKCC1 expression in GASH/Sal animals, which overlaps with changes in GABA release. These observations provide evidence for the critical role of NKCC1 in how seizures affect neuronal excitability, and support NKCC1 contribution to the development of secondary foci of epileptogenic activity.
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Affiliation(s)
- Juan-Manuel Bonet-Fernández
- Neuropsychopharmacology Unit, Research Department, Albacete General Hospital, Albacete, Spain
- Biomedical Instrumentation Service, Faculty of Medicine, University of Castilla-La Mancha, Albacete, Spain
| | - Pedro Tranque
- Biomedical Instrumentation Service, Faculty of Medicine, University of Castilla-La Mancha, Albacete, Spain
- Department of Medical Sciences, Faculty of Medicine, University of Castilla-La Mancha, Albacete, Spain
| | - Jose Daniel Aroca-Aguilar
- Department of Genetics, Faculty of Medicine/Instituto de Investigación en Discapacidades Neurológicas (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Luis J. Muñoz
- Instituto de Neurociencias de Castilla y León (INCYL), University of Salamanca, Salamanca, Spain
| | - Dolores E. López
- Instituto de Neurociencias de Castilla y León (INCYL), University of Salamanca, Salamanca, Spain
| | - Julio Escribano
- Department of Genetics, Faculty of Medicine/Instituto de Investigación en Discapacidades Neurológicas (IDINE), University of Castilla-La Mancha, Albacete, Spain
| | - Carlos de Cabo
- Neuropsychopharmacology Unit, Research Department, Albacete General Hospital, Albacete, Spain
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11
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Anagnostakis F, Kokkorakis M, Markouli M, Piperi C. Impact of Solute Carrier Transporters in Glioma Pathology: A Comprehensive Review. Int J Mol Sci 2023; 24:ijms24119393. [PMID: 37298344 DOI: 10.3390/ijms24119393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/25/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
Solute carriers (SLCs) are essential for brain physiology and homeostasis due to their role in transporting necessary substances across cell membranes. There is an increasing need to further unravel their pathophysiological implications since they have been proposed to play a pivotal role in brain tumor development, progression, and the formation of the tumor microenvironment (TME) through the upregulation and downregulation of various amino acid transporters. Due to their implication in malignancy and tumor progression, SLCs are currently positioned at the center of novel pharmacological targeting strategies and drug development. In this review, we discuss the key structural and functional characteristics of the main SLC family members involved in glioma pathogenesis, along with their potential targeting options to provide new opportunities for CNS drug design and more effective glioma management.
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Affiliation(s)
- Filippos Anagnostakis
- Department of Medical and Surgical Sciences, University of Bologna, 40126 Bologna, Italy
| | - Michail Kokkorakis
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, 9700 RB Groningen, The Netherlands
| | - Mariam Markouli
- Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Christina Piperi
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
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12
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Del Turco D, Paul MH, Schlaudraff J, Muellerleile J, Bozic F, Vuksic M, Jedlicka P, Deller T. Layer-specific changes of KCC2 and NKCC1 in the mouse dentate gyrus after entorhinal denervation. Front Mol Neurosci 2023; 16:1118746. [PMID: 37293543 PMCID: PMC10244516 DOI: 10.3389/fnmol.2023.1118746] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 04/25/2023] [Indexed: 06/10/2023] Open
Abstract
The cation-chloride cotransporters KCC2 and NKCC1 regulate the intracellular Cl- concentration and cell volume of neurons and/or glia. The Cl- extruder KCC2 is expressed at higher levels than the Cl- transporter NKCC1 in mature compared to immature neurons, accounting for the developmental shift from high to low Cl- concentration and from depolarizing to hyperpolarizing currents through GABA-A receptors. Previous studies have shown that KCC2 expression is downregulated following central nervous system injury, returning neurons to a more excitable state, which can be pathological or adaptive. Here, we show that deafferentation of the dendritic segments of granule cells in the outer (oml) and middle (mml) molecular layer of the dentate gyrus via entorhinal denervation in vivo leads to cell-type- and layer-specific changes in the expression of KCC2 and NKCC1. Microarray analysis validated by reverse transcription-quantitative polymerase chain reaction revealed a significant decrease in Kcc2 mRNA in the granule cell layer 7 days post-lesion. In contrast, Nkcc1 mRNA was upregulated in the oml/mml at this time point. Immunostaining revealed a selective reduction in KCC2 protein expression in the denervated dendrites of granule cells and an increase in NKCC1 expression in reactive astrocytes in the oml/mml. The NKCC1 upregulation is likely related to the increased activity of astrocytes and/or microglia in the deafferented region, while the transient KCC2 downregulation in granule cells may be associated with denervation-induced spine loss, potentially also serving a homeostatic role via boosting GABAergic depolarization. Furthermore, the delayed KCC2 recovery might be involved in the subsequent compensatory spinogenesis.
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Affiliation(s)
- Domenico Del Turco
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Mandy H. Paul
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Jessica Schlaudraff
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Julia Muellerleile
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Fran Bozic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Mario Vuksic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Peter Jedlicka
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
- Faculty of Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Frankfurt, Germany
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13
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Pressey JC, de Saint-Rome M, Raveendran VA, Woodin MA. Chloride transporters controlling neuronal excitability. Physiol Rev 2023; 103:1095-1135. [PMID: 36302178 DOI: 10.1152/physrev.00025.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Synaptic inhibition plays a crucial role in regulating neuronal excitability, which is the foundation of nervous system function. This inhibition is largely mediated by the neurotransmitters GABA and glycine that activate Cl--permeable ion channels, which means that the strength of inhibition depends on the Cl- gradient across the membrane. In neurons, the Cl- gradient is primarily mediated by two secondarily active cation-chloride cotransporters (CCCs), NKCC1 and KCC2. CCC-mediated regulation of the neuronal Cl- gradient is critical for healthy brain function, as dysregulation of CCCs has emerged as a key mechanism underlying neurological disorders including epilepsy, neuropathic pain, and autism spectrum disorder. This review begins with an overview of neuronal chloride transporters before explaining the dependent relationship between these CCCs, Cl- regulation, and inhibitory synaptic transmission. We then discuss the evidence for how CCCs can be regulated, including by activity and their protein interactions, which underlie inhibitory synaptic plasticity. For readers who may be interested in conducting experiments on CCCs and neuronal excitability, we have included a section on techniques for estimating and recording intracellular Cl-, including their advantages and limitations. Although the focus of this review is on neurons, we also examine how Cl- is regulated in glial cells, which in turn regulate neuronal excitability through the tight relationship between this nonneuronal cell type and synapses. Finally, we discuss the relatively extensive and growing literature on how CCC-mediated neuronal excitability contributes to neurological disorders.
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Affiliation(s)
- Jessica C Pressey
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Miranda de Saint-Rome
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Vineeth A Raveendran
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Melanie A Woodin
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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14
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Luhmann HJ. Malformations-related neocortical circuits in focal seizures. Neurobiol Dis 2023; 178:106018. [PMID: 36706927 DOI: 10.1016/j.nbd.2023.106018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 01/18/2023] [Accepted: 01/23/2023] [Indexed: 01/25/2023] Open
Abstract
This review article gives an overview on the molecular, cellular and network mechanisms underlying focal seizures in neocortical networks with developmental malformations. Neocortical malformations comprise a large variety of structural abnormalities associated with epilepsy and other neurological and psychiatric disorders. Genetic or acquired disorders of neocortical cell proliferation, neuronal migration and/or programmed cell death may cause pathologies ranging from the expression of dysmorphic neurons and heterotopic cell clusters to abnormal layering and cortical misfolding. After providing a brief overview on the pathogenesis and structure of neocortical malformations in humans, animal models are discussed and how they contributed to our understanding on the mechanisms of neocortical hyperexcitability associated with developmental disorders. State-of-the-art molecular biological and electrophysiological techniques have been also used in humans and on resectioned neocortical tissue of epileptic patients and provide deep insights into the subcellular, cellular and network mechanisms contributing to focal seizures. Finally, a brief outlook is given how novel models and methods can shape translational research in the near future.
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Affiliation(s)
- Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz, Germany.
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15
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Chloride ion dysregulation in epileptogenic neuronal networks. Neurobiol Dis 2023; 177:106000. [PMID: 36638891 DOI: 10.1016/j.nbd.2023.106000] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/25/2022] [Accepted: 01/09/2023] [Indexed: 01/13/2023] Open
Abstract
GABA is the major inhibitory neurotransmitter in the mature CNS. When GABAA receptors are activated the membrane potential is driven towards hyperpolarization due to chloride entry into the neuron. However, chloride ion dysregulation that alters the ionic gradient can result in depolarizing GABAergic post-synaptic potentials instead. In this review, we highlight that GABAergic inhibition prevents and restrains focal seizures but then reexamine this notion in the context of evidence that a static and/or a dynamic chloride ion dysregulation, that increases intracellular chloride ion concentrations, promotes epileptiform activity and seizures. To reconcile these findings, we hypothesize that epileptogenic pathologically interconnected neuron (PIN) microcircuits, representing a small minority of neurons, exhibit static chloride dysregulation and should exhibit depolarizing inhibitory post-synaptic potentials (IPSPs). We speculate that chloride ion dysregulation and PIN cluster activation may generate fast ripples and epileptiform spikes as well as initiate the hypersynchronous seizure onset pattern and microseizures. Also, we discuss the genetic, molecular, and cellular players important in chloride dysregulation which regulate epileptogenesis and initiate the low-voltage fast seizure onset pattern. We conclude that chloride dysregulation in neuronal networks appears to be critical for epileptogenesis and seizure genesis, but feed-back and feed-forward inhibitory GABAergic neurotransmission plays an important role in preventing and restraining seizures as well.
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16
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Liu R, Xing Y, Zhang H, Wang J, Lai H, Cheng L, Li D, Yu T, Yan X, Xu C, Piao Y, Zeng L, Loh HH, Zhang G, Yang X. Imbalance between the function of Na+-K+-2Cl and K+-Cl impairs Cl– homeostasis in human focal cortical dysplasia. Front Mol Neurosci 2022; 15:954167. [PMID: 36324524 PMCID: PMC9621392 DOI: 10.3389/fnmol.2022.954167] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 09/27/2022] [Indexed: 11/29/2022] Open
Abstract
Objective Altered expression patterns of Na+-K+-2Cl– (NKCC1) and K+-Cl– (KCC2) co-transporters have been implicated in the pathogenesis of epilepsy. Here, we assessed the effects of imbalanced NKCC1 and KCC2 on γ-aminobutyric acidergic (GABAergic) neurotransmission in certain brain regions involved in human focal cortical dysplasia (FCD). Materials and methods We sought to map a micro-macro neuronal network to better understand the epileptogenesis mechanism. In patients with FCD, we resected cortical tissue from the seizure the onset zone (SOZ) and the non-seizure onset zone (non-SOZ) inside the epileptogenic zone (EZ). Additionally, we resected non-epileptic neocortical tissue from the patients with mesial temporal lobe epilepsy (MTLE) as control. All of tissues were analyzed using perforated patch recordings. NKCC1 and KCC2 co-transporters expression and distribution were analyzed by immunohistochemistry and western blotting. Results Results revealed that depolarized GABAergic signals were observed in pyramidal neurons in the SOZ and non-SOZ groups compared with the control group. The total number of pyramidal neurons showing GABAergic spontaneous postsynaptic currents was 11/14, 7/17, and 0/12 in the SOZ, non-SOZ, and control groups, respectively. The depolarizing GABAergic response was significantly dampened by the specific NKCC1 inhibitor bumetanide (BUM). Patients with FCD exhibited higher expression and internalized distribution of KCC2, particularly in the SOZ group. Conclusion Our results provide evidence of a potential neurocircuit underpinning SOZ epileptogenesis and non-SOZ seizure susceptibility. Imbalanced function of NKCC1 and KCC2 may affect chloride ion homeostasis in neurons and alter GABAergic inhibitory action, thereby contributing to epileptogenesis in FCDs. Maintaining chloride ion homeostasis in the neurons may represent a new avenue for the development of novel anti-seizure medications (ASMs).
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Affiliation(s)
- Ru Liu
- Guangzhou Laboratory, Guangzhou, China
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
- Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yue Xing
- Guangzhou Laboratory, Guangzhou, China
| | | | - Junling Wang
- Guangzhou Laboratory, Guangzhou, China
- Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
- Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing, China
| | | | - Lipeng Cheng
- Guangzhou Laboratory, Guangzhou, China
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
- Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Donghong Li
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Tao Yu
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xiaoming Yan
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Cuiping Xu
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yueshan Piao
- Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Linghui Zeng
- Department of Pharmacology, Zhejiang University City College, Hangzhou, China
| | | | - Guojun Zhang
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- *Correspondence: Guojun Zhang,
| | - Xiaofeng Yang
- Guangzhou Laboratory, Guangzhou, China
- Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing, China
- Xiaofeng Yang,
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17
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The Comparative Experimental Study of Sodium and Magnesium Dichloroacetate Effects on Pediatric PBT24 and SF8628 Cell Glioblastoma Tumors Using a Chicken Embryo Chorioallantoic Membrane Model and on Cells In Vitro. Int J Mol Sci 2022; 23:ijms231810455. [PMID: 36142368 PMCID: PMC9499689 DOI: 10.3390/ijms231810455] [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: 08/16/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022] Open
Abstract
In this study, pyruvate dehydrogenase kinase-1 inhibition with dichloroacetate (DCA) was explored as an alternative cancer therapy. The study’s aim was to compare the effectiveness of NaDCA and MgDCA on pediatric glioblastoma PBT24 and SF8628 tumors and cells. The treatment effects were evaluated on xenografts growth on a chicken embryo chorioallantoic membrane. The PCNA, EZH2, p53, survivin expression in tumor, and the SLC12A2, SLC12A5, SLC5A8, CDH1, and CDH2 expression in cells were studied. The tumor groups were: control, cells treated with 10 mM and 5 mM of NaDCA, and 5 mM and 2.5 mM of MgDCA. The cells were also treated with 3 mM DCA. Both the 10 mM DCA preparations significantly reduced PBT24 and SF8624 tumor invasion rates, while 5 mM NaDCA reduced it only in the SF8628 tumors. The 5 mM MgDCA inhibited tumor-associated neoangiogenesis in PBT24; both doses of NaDCA inhibited tumor-associated neoangiogenesis in SF8628. The 10 mM DCA inhibited the expression of markers tested in PBT24 and SF8628 tumors, but the 5 mM DCA affect on their expression depended on the cation. The DCA treatment did not affect the SLC12A2, SLC12A5, and SLC5A8 expression in cells but increased CDH1 expression in SF8628. The tumor response to DCA at different doses indicated that a contrast between NaDCA and MgDCA effectiveness reflects the differences in the tested cells’ biologies.
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Shao Y, Ge Q, Yang J, Wang M, Zhou Y, Guo JX, Zhu M, Shi J, Hu Y, Shen L, Chen Z, Li XM, Zhu JM, Zhang J, Duan S, Chen J. Pathological Networks Involving Dysmorphic Neurons in Type II Focal Cortical Dysplasia. Neurosci Bull 2022; 38:1007-1024. [PMID: 35235180 PMCID: PMC9468210 DOI: 10.1007/s12264-022-00828-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/24/2021] [Indexed: 10/19/2022] Open
Abstract
Focal cortical dysplasia (FCD) is one of the most common causes of drug-resistant epilepsy. Dysmorphic neurons are the major histopathological feature of type II FCD, but their role in seizure genesis in FCD is unclear. Here we performed whole-cell patch-clamp recording and morphological reconstruction of cortical principal neurons in postsurgical brain tissue from drug-resistant epilepsy patients. Quantitative analyses revealed distinct morphological and electrophysiological characteristics of the upper layer dysmorphic neurons in type II FCD, including an enlarged soma, aberrant dendritic arbors, increased current injection for rheobase action potential firing, and reduced action potential firing frequency. Intriguingly, the upper layer dysmorphic neurons received decreased glutamatergic and increased GABAergic synaptic inputs that were coupled with upregulation of the Na+-K+-Cl- cotransporter. In addition, we found a depolarizing shift of the GABA reversal potential in the CamKII-cre::PTENflox/flox mouse model of drug-resistant epilepsy, suggesting that enhanced GABAergic inputs might depolarize dysmorphic neurons. Thus, imbalance of synaptic excitation and inhibition of dysmorphic neurons may contribute to seizure genesis in type II FCD.
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Affiliation(s)
- Yijie Shao
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Department of Neurosurgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Qianqian Ge
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jiachao Yang
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Mi Wang
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Yu Zhou
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jin-Xin Guo
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
| | - Mengyue Zhu
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jiachen Shi
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Yiqi Hu
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Li Shen
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, 310058, China
- Department of Orthopedic Surgery, School of Medicine, the Second Affiliated Hospital, Zhejiang University, Hangzhou, 310009, China
- Hangzhou Innovation Center, Zhejiang University, Hangzhou, 310058, China
| | - Zhong Chen
- Institute of Pharmacology & Toxicology, NHC and CAMS Key Laboratory of Medical Neurobiology, College of Pharmaceutical Sciences, School of Basic Medical Sciences, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310058, China
| | - Xiao-Ming Li
- Center for Neuroscience and Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Center for Brain Science and Brain-Inspired Intelligence, Joint Institute for Genetics and Genome Medicine between, Guangdong Hong Kong Macao Greater Bay Area, Zhejiang University and the University of Toronto, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jun-Ming Zhu
- Department of Neurosurgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Jianmin Zhang
- Department of Neurosurgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China.
| | - Shumin Duan
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China.
| | - Jiadong Chen
- Center for Neuroscience and Department of Neurosurgery of the Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China.
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Genetic pathogenesis of the epileptogenic lesions in Tuberous Sclerosis Complex: Therapeutic targeting of the mTOR pathway. Epilepsy Behav 2022; 131:107713. [PMID: 33431351 DOI: 10.1016/j.yebeh.2020.107713] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 12/14/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022]
Abstract
Tuberous sclerosis complex (TSC) is a genetic multisystem disease due to the mutation in one of the two genes TSC1 and TSC2, affecting several organs and systems and carrying a significant risk of early onset and refractory seizures. The pathogenesis of this complex disorder is now well known, with most of TSC-related manifestations being a consequence of the overactivation of the mammalian Target of Rapamycin (mTOR) complex. The discovery of this underlying mechanism paved the way for the use of a class of drugs called mTOR inhibitors including rapamycin and everolimus and specifically targeting this pathway. Rapamycin has been widely used in different animal models of TSC-related epilepsy and proved to be able not only to suppress seizures but also to prevent the development of epilepsy, thus demonstrating an antiepileptogenic potential. In some models, it also showed some benefit on neuropsychiatric manifestations associated with TSC. Everolimus has recently been approved by the US Food and Drug Administration and the European Medical Agency for the treatment of refractory seizures associated with TSC starting from the age of 2 years. It demonstrated a clear benefit when compared to placebo on reducing the frequency of different seizure types and exerting a higher effect in younger children. In conclusion, mTOR cascade can be a potentially major cause of TSC-associated epilepsy and neurodevelopmental disability, and additional research should investigate if early suppression of abnormal mTOR signal with mTOR inhibitors before seizure onset can be a more efficient approach and an effective antiepileptogenic and disease-modifying strategy in infants with TSC.
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Damanskienė E, Balnytė I, Valančiūtė A, Alonso MM, Stakišaitis D. Different Effects of Valproic Acid on SLC12A2, SLC12A5 and SLC5A8 Gene Expression in Pediatric Glioblastoma Cells as an Approach to Personalised Therapy. Biomedicines 2022; 10:968. [PMID: 35625705 PMCID: PMC9138981 DOI: 10.3390/biomedicines10050968] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 02/04/2023] Open
Abstract
Valproic acid (VPA) is a histone deacetylase inhibitor with sex-specific immunomodulatory and anticancer effects. This study aimed to investigate the effect of 0.5 and 0.75 mM VPA on NKCC1 (SLC12A2), KCC2 (SLC12A5) and SLC5A8 (SLC5A8) co-transporter gene expressions in pediatric PBT24 (boy's) and SF8628 (girl's) glioblastoma cells. The SLC12A2, SLC12A5 and SLC5A8 RNA expressions were determined by the RT-PCR method. The SLC12A2 and SLC5A8 expressions did not differ between the PBT24 and SF8628 controls. The SLC12A5 expression in the PBT24 control was significantly higher than in the SF8628 control. VPA treatment significantly increased the expression of SLC12A2 in PBT24 but did not affect SF8628 cells. VPA increased the SLC12A5 expression in PBT24 and SF8628 cells. The SLC12A5 expression of the PBT24-treated cells was significantly higher than in corresponding SF8628 groups. Both VPA doses increased the SLC5A8 expression in PBT24 and SF8628 cells, but the expression was significantly higher in the PBT24-treated, compared to the respective SF8628 groups. The SLC5A8 expression in PBT24-treated cells was 10-fold higher than in SF8628 cells. The distinct effects of VPA on the expression of SLC12A2, SLC12A5 and SLC5A8 in PBT24 and SF8628 glioblastoma cells suggest differences in tumor cell biology that may be gender-related.
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Affiliation(s)
- Eligija Damanskienė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (E.D.); (I.B.); (A.V.)
| | - Ingrida Balnytė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (E.D.); (I.B.); (A.V.)
| | - Angelija Valančiūtė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (E.D.); (I.B.); (A.V.)
| | - Marta Marija Alonso
- Department of Pediatrics, Clínica Universidad de Navarra, University of Navarra, 31008 Pamplona, Spain;
| | - Donatas Stakišaitis
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (E.D.); (I.B.); (A.V.)
- Laboratory of Molecular Oncology, National Cancer Institute, 08660 Vilnius, Lithuania
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21
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Damanskienė E, Balnytė I, Valančiūtė A, Alonso MM, Preikšaitis A, Stakišaitis D. The Different Temozolomide Effects on Tumorigenesis Mechanisms of Pediatric Glioblastoma PBT24 and SF8628 Cell Tumor in CAM Model and on Cells In Vitro. Int J Mol Sci 2022; 23:ijms23042001. [PMID: 35216113 PMCID: PMC8877228 DOI: 10.3390/ijms23042001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/04/2022] [Accepted: 02/06/2022] [Indexed: 02/05/2023] Open
Abstract
It is necessary to elucidate the individual effects of temozolomide (TMZ) on carcinogenesis and tumor resistance to chemotherapy mechanisms. The study aimed to investigate the TMZ 50 and 100 μM dose effect difference between PBT24 and SF8628 cell line high-grade pediatric glioblastoma (phGBM) xenografts in a chicken chorioallantoic membrane (CAM) model, on PCNA and EZH2 immunohistochemical expression in the tumor and on the expression of NKCC1, KCC2, E- and N-cadherin genes in TMZ-treated and control cell groups in vitro. TMZ at a 100 μg dose reduced the incidence of PBT24 xenograft invasion into the CAM, CAM thickening and the number of blood vessels in the CAM (p < 0.05), but did not affect the SF8628 tumor in the CAM model. The TMZ impact on PBT24 and SF8628 tumor PCNA expression was similarly significantly effective but did not alter EZH2 expression in the studied tumors. The TMZ at 50 μM caused significantly increased RNA expression of the NKCC1 gene in both studied cell types compared with controls (p < 0.05). The expression of the KCC2 gene was increased in PBT24 TMZ-treated cells (p < 0.05), and no TMZ effect was found in SF8628-treated cells. The study supports the suggestion that individual sensitivity to TMZ should be assessed when starting treatment.
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Affiliation(s)
- Eligija Damanskienė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (I.B.); (A.V.)
- Correspondence: (E.D.); (D.S.)
| | - Ingrida Balnytė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (I.B.); (A.V.)
| | - Angelija Valančiūtė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (I.B.); (A.V.)
| | - Marta Maria Alonso
- Department of Pediatrics, Clínica Universidad de Navarra, University of Navarra, 31008 Pamplona, Spain;
| | - Aidanas Preikšaitis
- Centre of Neurosurgery, Clinic of Neurology and Neurosurgery, Faculty of Medicine, Vilnius University, 03101 Vilnius, Lithuania;
| | - Donatas Stakišaitis
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania; (I.B.); (A.V.)
- Laboratory of Molecular Oncology, National Cancer Institute, 08660 Vilnius, Lithuania
- Correspondence: (E.D.); (D.S.)
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22
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Wada K, Sonoda M, Firestone E, Sakakura K, Kuroda N, Takayama Y, Iijima K, Iwasaki M, Mihara T, Goto T, Asano E, Miyazaki T. Sevoflurane-based enhancement of phase-amplitude coupling and localization of the epileptogenic zone. Clin Neurophysiol 2022; 134:1-8. [PMID: 34922194 PMCID: PMC8766927 DOI: 10.1016/j.clinph.2021.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/05/2021] [Accepted: 11/03/2021] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Phase-amplitude coupling between high-frequency (≥150 Hz) and delta (3-4 Hz) oscillations - modulation index (MI) - is a promising, objective biomarker of epileptogenicity. We determined whether sevoflurane anesthesia preferentially enhances this metric within the epileptogenic zone. METHODS This is an observational study of intraoperative electrocorticography data from 621 electrodes chronically implanted into eight patients with drug-resistant, focal epilepsy. All patients were anesthetized with sevoflurane during resective surgery, which subsequently resulted in seizure control. We classified 'removed' and 'retained' brain sites as epileptogenic and non-epileptogenic, respectively. Mixed model analysis determined which anesthetic stage optimized MI-based classification of epileptogenic sites. RESULTS MI increased as a function of anesthetic stage, ranging from baseline (i.e., oxygen alone) to 2.0 minimum alveolar concentration (MAC) of sevoflurane, preferentially at sites showing higher initial MI values. This phenomenon was accentuated just prior to sevoflurane reaching 2.0 MAC, at which time, the odds of a site being classified as epileptogenic were enhanced by 86.6 times for every increase of 1.0 MI. CONCLUSIONS Intraoperative MI best localized the epileptogenic zone immediately before sevoflurane reaching 2.0 MAC in this small cohort of patients. SIGNIFICANCE Prospective, large cohort studies are warranted to determine whether sevoflurane anesthesia can reduce the need for extraoperative, invasive evaluation.
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Affiliation(s)
- Keiko Wada
- Department of Anesthesiology, National Center Hospital, National Center of Neurology and Psychiatry, Kodaira, Tokyo 1878551, Japan,Department of Anesthesiology and Critical Care, Yokohama City University Graduate School of Medicine, Yokohama, 2360004, Japan
| | - Masaki Sonoda
- Department of Pediatrics, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA,Department of Neurosurgery, Yokohama City University Graduate School of Medicine, Yokohama 2360004, Japan
| | - Ethan Firestone
- Department of Pediatrics, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA,Department of Physiology, Wayne State University, Detroit, MI 48201, USA
| | - Kazuki Sakakura
- Department of Pediatrics, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA,Department of Neurosurgery, University of Tsukuba, Tsukuba, 3058575, Japan
| | - Naoto Kuroda
- Department of Pediatrics, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA,Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai 9808575, Japan
| | - Yutaro Takayama
- Department of Neurosurgery, Yokohama City University Graduate School of Medicine, Yokohama 2360004, Japan,Department of Neurosurgery, National Center Hospital, National Center of Neurology and Psychiatry, Kodaira, Tokyo 1878551, Japan
| | - Keiya Iijima
- Department of Neurosurgery, National Center Hospital, National Center of Neurology and Psychiatry, Kodaira, Tokyo 1878551, Japan
| | - Masaki Iwasaki
- Department of Neurosurgery, National Center Hospital, National Center of Neurology and Psychiatry, Kodaira, Tokyo 1878551, Japan
| | - Takahiro Mihara
- Department of Anesthesiology and Critical Care, Yokohama City University Graduate School of Medicine, Yokohama, 2360004, Japan,Department of Health Data Science, Yokohama City University Graduate School of Data Science, Yokohama, 2360027, Japan
| | - Takahisa Goto
- Department of Anesthesiology and Critical Care, Yokohama City University Graduate School of Medicine, Yokohama, 2360004, Japan
| | - Eishi Asano
- Department of Pediatrics, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA,Department of Neurology, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA,E.A. and T.M. share the senior authorship. Corresponding Authors: Eishi Asano, M.D., Ph.D., M.S. (C.R.D.S.A.), Address: Division of Pediatric Neurology, Children’s Hospital of Michigan, Wayne State University. 3901 Beaubien St., Detroit, MI, 48201, USA, Phone: +1-313-745-5547, FAX: +1-313-745-9435, and Tomoyuki Miyazaki, M.D., Ph.D., Address: Department of Physiology/Anesthesiology, Yokohama City University Graduate School of Medicine. 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, Japan, Phone: +81-45-787-2918, FAX: +81-45-787-2917,
| | - Tomoyuki Miyazaki
- Department of Anesthesiology and Critical Care, Yokohama City University Graduate School of Medicine, Yokohama, 2360004, Japan,Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 2360004, Japan,E.A. and T.M. share the senior authorship. Corresponding Authors: Eishi Asano, M.D., Ph.D., M.S. (C.R.D.S.A.), Address: Division of Pediatric Neurology, Children’s Hospital of Michigan, Wayne State University. 3901 Beaubien St., Detroit, MI, 48201, USA, Phone: +1-313-745-5547, FAX: +1-313-745-9435, and Tomoyuki Miyazaki, M.D., Ph.D., Address: Department of Physiology/Anesthesiology, Yokohama City University Graduate School of Medicine. 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, Japan, Phone: +81-45-787-2918, FAX: +81-45-787-2917,
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23
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Kilb W. When Are Depolarizing GABAergic Responses Excitatory? Front Mol Neurosci 2021; 14:747835. [PMID: 34899178 PMCID: PMC8651619 DOI: 10.3389/fnmol.2021.747835] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/28/2021] [Indexed: 11/13/2022] Open
Abstract
The membrane responses upon activation of GABA(A) receptors critically depend on the intracellular Cl− concentration ([Cl−]i), which is maintained by a set of transmembrane transporters for Cl−. During neuronal development, but also under several pathophysiological conditions, the prevailing expression of the Cl− loader NKCC1 and the low expression of the Cl− extruder KCC2 causes elevated [Cl−]i, which result in depolarizing GABAergic membrane responses. However, depolarizing GABAergic responses are not necessarily excitatory, as GABA(A) receptors also reduces the input resistance of neurons and thereby shunt excitatory inputs. To summarize our knowledge on the effect of depolarizing GABA responses on neuronal excitability, this review discusses theoretical considerations and experimental studies illustrating the relation between GABA conductances, GABA reversal potential and neuronal excitability. In addition, evidences for the complex spatiotemporal interaction between depolarizing GABAergic and glutamatergic inputs are described. Moreover, mechanisms that influence [Cl−]i beyond the expression of Cl− transporters are presented. And finally, several in vitro and in vivo studies that directly investigated whether GABA mediates excitation or inhibition during early developmental stages are summarized. In summary, these theoretical considerations and experimental evidences suggest that GABA can act as inhibitory neurotransmitter even under conditions that maintain substantial depolarizing membrane responses.
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Affiliation(s)
- Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
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24
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Malformations of Cortical Development, Cognitive Involvementand Epilepsy: A Single Institution Experience in 19 Young Patients. CHILDREN-BASEL 2021; 8:children8080637. [PMID: 34438528 PMCID: PMC8392186 DOI: 10.3390/children8080637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 07/07/2021] [Accepted: 07/22/2021] [Indexed: 11/16/2022]
Abstract
BACKGROUND Malformations of cortical development (MCD) include a wide range of congenital disorders mostly causing severe cognitive dysfunction and epilepsy. OBJECTIVE to report on clinical features including cognitive involvement, epileptic seizures with response to antiseizure medications, comorbidities in young patients affected by MCD and followed in a single tertiary hospital. PATIENTS AND METHODS A retrospective review of the medical records and magnetic resonance images (MRI) of 19 young patients with an age ranging between eight days and fifteen years affected by MCD and admitted to Pediatrics Department University of Catania, Italy from October 2009 and October 2020 were selected. Patients were distinguished in three groups following the Barcovich et al. 2012 classification for MCD: 4 (21%) in Group I; 8 (42%) in Group II; and, and 7 (37%) in Group III. Clinical features and MRI of the patients including cognitive involvement, epilepsy type and response to drugs treatment were analyzed. RESULTS In Group I, two patients showed cortical dysplasia and two dysembryoplastic neuroepithelial tumors plus focal cortical dysplasia; developmental delay/intellectual disability (DD/ID) was severe in one, moderate in one and absent in two; the type of seizures was in all the cases focal to bilateral tonic-clonic (FBTCs), and drug resistant was found in one case. In Group II, three patients showed neuronal hetero-topias and five had pachygyria-lissencephaly: DD/ID was severe in four, moderate in two, and absent in two; the type of seizure was focal (FS) in five, focal to bilateral tonic-clonic (FBTCs) in two, infantile spasms (IS) in one, and drug resistant was found in three. In Group III, six showed polymicrogyria and one schizencephaly: DD/ID was found severe in five, moderate in two, and the type of seizure was focal (FS) in five, FBTCS in two, and drug resistance was found in three.
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25
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Virtanen MA, Uvarov P, Hübner CA, Kaila K. NKCC1, an Elusive Molecular Target in Brain Development: Making Sense of the Existing Data. Cells 2020; 9:cells9122607. [PMID: 33291778 PMCID: PMC7761970 DOI: 10.3390/cells9122607] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 12/14/2022] Open
Abstract
Ionotropic GABA transmission is mediated by anion (mainly Cl−)-permeable GABAA receptors (GABAARs). In immature neurons, GABA exerts depolarizing and sometimes functionally excitatory actions, based on active uptake of Cl− by the Na-K-2Cl cotransporter NKCC1. While functional evidence firmly shows NKCC1-mediated ion transport in immature and diseased neurons, molecular detection of NKCC1 in the brain has turned out to be extremely difficult. In this review, we describe the highly inconsistent data that are available on the cell type-specific expression patterns of the NKCC1 mRNA and protein in the CNS. We discuss the major technical caveats, including a lack of knock-out-controlled immunohistochemistry in the forebrain, possible effects of alternative splicing on the binding of antibodies and RNA probes, and the wide expression of NKCC1 in different cell types, which make whole-tissue analyses of NKCC1 useless for studying its neuronal expression. We also review novel single-cell RNAseq data showing that most of the NKCC1 in the adult CNS may, in fact, be expressed in non-neuronal cells, especially in glia. As future directions, we suggest single-cell NKCC1 mRNA and protein analyses and the use of genetically tagged endogenous proteins or systematically designed novel antibodies, together with proper knock-out controls, for the visualization of endogenous NKCC1 in distinct brain cell types and their subcellular compartments.
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Affiliation(s)
- Mari A. Virtanen
- Molecular and Integrative Biosciences, University of Helsinki, 00014 Helsinki, Finland; (M.A.V.); (P.U.)
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
| | - Pavel Uvarov
- Molecular and Integrative Biosciences, University of Helsinki, 00014 Helsinki, Finland; (M.A.V.); (P.U.)
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
| | - Christian A. Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller Universität, 07747 Jena, Germany;
| | - Kai Kaila
- Molecular and Integrative Biosciences, University of Helsinki, 00014 Helsinki, Finland; (M.A.V.); (P.U.)
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
- Correspondence: ; Tel.: +358-407256759
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26
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Luo L, Wang J, Ding D, Hasan MN, Yang SS, Lin SH, Schreppel P, Sun B, Yin Y, Erker T, Sun D. Role of NKCC1 Activity in Glioma K + Homeostasis and Cell Growth: New Insights With the Bumetanide-Derivative STS66. Front Physiol 2020; 11:911. [PMID: 32848856 PMCID: PMC7413028 DOI: 10.3389/fphys.2020.00911] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/08/2020] [Indexed: 12/01/2022] Open
Abstract
Introduction: Na+-K+-2Cl− cotransporter isoform 1 (NKCC1) is important in regulating intracellular K+ and Cl− homeostasis and cell volume. In this study, we investigated a role of NKCC1 in regulating glioma K+ influx and proliferation in response to apoptosis inducing chemotherapeutic drug temozolomide (TMZ). The efficacy of a new bumetanide (BMT)-derivative NKCC1 inhibitor STS66 [3-(butylamino)-2-phenoxy-5-[(2, 2, 2-trifluoroethylamino) methyl] benzenesulfonamide] in blocking NKCC1 activity was compared with well-established NKCC1 inhibitor BMT. Methods: NKCC1 activity in cultured mouse GL26 and SB28-GFP glioma cells was measured by Rb+ (K+) influx. The WNK1-SPAK/OSR1-NKCC1 signaling and AKT/ERK-mTOR signaling protein expression and activation were assessed by immunoblotting. Cell growth was determined by bromodeoxyuridine (BrdU) incorporation assay, MTT proliferation assay, and cell cycle analysis. Impact of STS66 and BMT on cell Rb+ influx and growth was measured in glioma cells treated with or without TMZ. Results: Rb+ influx assay showed that 10 μM BMT markedly decreased the total Rb+ influx and no additional inhibition detected at >10 μM BMT. In contrast, the maximum effects of STS66 on Rb+ influx inhibition were at 40–60 μM. Both BMT and STS66 reduced TMZ-mediated NKCC1 activation and protein upregulation. Glioma cell growth can be reduced by STS66. The most robust inhibition of glioma growth, cell cycle, and AKT/ERK signaling was achieved by the TMZ + STS66 treatment. Conclusion: The new BMT-derivative NKCC1 inhibitor STS66 is more effective than BMT in reducing glioma cell growth in part by inhibiting NKCC1-mediated K+ influx. TMZ + STS66 combination treatment reduces glioma cell growth via inhibiting cell cycle and AKT-ERK signaling.
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Affiliation(s)
- Lanxin Luo
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States
| | - Jun Wang
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, China
| | - Dawei Ding
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Neurosurgery, University of Minnesota, Minneapolis, MN, United States
| | - Md Nabiul Hasan
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Sung-Sen Yang
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Shih-Hua Lin
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Philipp Schreppel
- Department of Medicinal Chemistry, University of Vienna, Vienna, Austria
| | - Baoshan Sun
- Pólo Dois Portos, Instituto National de Investigação Agrária e Veterinária, I.P., Quinta da Almoinha, Dois Portos, Portugal
| | - Yan Yin
- Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, China
| | - Thomas Erker
- Department of Medicinal Chemistry, University of Vienna, Vienna, Austria
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States.,Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA, United States
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27
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Han P, Welsh CT, Smith MT, Schmidt RE, Carroll SL. Complex Patterns of GABAergic Neuronal Deficiency and Type 2 Potassium-Chloride Cotransporter Immaturity in Human Focal Cortical Dysplasia. J Neuropathol Exp Neurol 2020; 78:365-372. [PMID: 30856249 DOI: 10.1093/jnen/nlz009] [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] [Indexed: 12/21/2022] Open
Abstract
Focal cortical dysplasia (FCD) is a common histopathologic finding in cortical specimens resected for refractory epilepsy. GABAergic neuronal abnormalities and K-Cl cotransporter type 2 (KCC2) immaturity may be contributing factors for FCD-related epilepsy. We examined surgical specimens from 12 cases diagnosed with FCD, and brain tissues without developmental abnormality obtained from 6 autopsy cases. We found that GABAergic neuronal density was abnormal in FCD with 2 distinct patterns. In 7 of 12 (58%) FCD subjects, the GABAergic neuron density in dysplastic regions and in neighboring nondysplastic regions was equally reduced, hence we call this a "broad pattern." In the remaining cases, GABAergic neuron density was decreased in dysplastic regions but not in the neighboring nondysplastic regions; we designate this "restricted pattern." The different patterns are not associated with pathologic subtypes of FCD. Intracytoplasmic retention of KCC2 is evident in dysmorphic neurons in the majority of FCD type II subjects (5/7) but not in FCD type I. Our study suggests that (1) "broad" GABAergic deficiency may reflect epileptic vulnerability outside the dysplastic area; and (2) abnormal distribution of KCC2 may contribute to seizure generation in patients with FCD type II but not in type I.
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Affiliation(s)
- Pengcheng Han
- Department of Pathology and Laboratory Medicine.,Department of Pathology and Laboratory Medicine Residency Program, Medical University of South Carolina, Charleston, South Carolina
| | | | | | - Robert E Schmidt
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
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28
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Ko A, Lee JS. Factors associated with seizure and cognitive outcomes after epilepsy surgery for low-grade epilepsy-associated neuroepithelial tumors in children. Clin Exp Pediatr 2020; 63:171-177. [PMID: 32024326 PMCID: PMC7254172 DOI: 10.3345/kjp.2019.01151] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 11/13/2019] [Indexed: 12/22/2022] Open
Abstract
Low-grade epilepsy-associated neuroepithelial tumors (LEATs) are responsible for drug-resistant chronic focal epilepsy, and are the second-most common reason for epilepsy surgery in children. LEATs are extremely responsive to surgical treatment, and therefore epilepsy surgery should be considered as a treatment option for LEATs. However, the optimal time for surgery remains controversial, and surgeries are often delayed. In this review, we reviewed published article on the factors associated with seizure and cognitive outcomes after epilepsy surgery for LEATs in children to help clinicians in their decision whether to pursue epilepsy surgery for LEATs. The achievement of gross total resection may be the most important prognostic factor for seizure freedom. A shorter duration of epilepsy, a younger age at surgery, and extended resection of temporal lobe tumors have also been suggested as favorable prognostic factors in terms of seizure control. Poor cognitive function in children with LEATs is associated with a longer duration of epilepsy and a younger age at seizure onset.
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Affiliation(s)
- Ara Ko
- Division of Pediatric Neurology, Department of Pediatrics, Pusan National University Children's Hospital, Pusan National University College of Medicine, Yangsan, Korea
| | - Joon Soo Lee
- Division of Pediatric Neurology, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
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29
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Liu R, Wang J, Liang S, Zhang G, Yang X. Role of NKCC1 and KCC2 in Epilepsy: From Expression to Function. Front Neurol 2020; 10:1407. [PMID: 32010056 PMCID: PMC6978738 DOI: 10.3389/fneur.2019.01407] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 12/23/2019] [Indexed: 01/21/2023] Open
Abstract
As a main inhibitory neurotransmitter in the central nervous system, γ-aminobutyric acid (GABA) activates chloride-permeable GABAa receptors (GABAa Rs) and induces chloride ion (Cl−) flow, which relies on the intracellular chloride concentration ([Cl−]i) of the postsynaptic neuron. The Na-K-2Cl cotransporter isoform 1 (NKCC1) and the K-Cl cotransporter isoform 2 (KCC2) are two main cation-chloride cotransporters (CCCs) that have been implicated in human epilepsy. NKCC1 and KCC2 reset [Cl−]i by accumulating and extruding Cl−, respectively. Previous studies have shown that the profile of NKCC1 and KCC2 in neonatal neurons may reappear in mature neurons under some pathophysiological conditions, such as epilepsy. Although increasing studies focusing on the expression of NKCC1 and KCC2 have suggested that impaired chloride plasticity may be closely related to epilepsy, additional neuroelectrophysiological research aimed at studying the functions of NKCC1 and KCC2 are needed to understand the exact mechanism by which they induce epileptogenesis. In this review, we aim to briefly summarize the current researches surrounding the expression and function of NKCC1 and KCC2 in epileptogenesis and its implications on the treatment of epilepsy. We will also explore the potential for NKCC1 and KCC2 to be therapeutic targets for the development of novel antiepileptic drugs.
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Affiliation(s)
- Ru Liu
- Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing, China.,Center of Epilepsy, Center for Brain Disorders Research, Capital Medical University, Beijing, China.,Center of Epilepsy, Beijing Institute of Brain Disorders, Beijing, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
| | - Junling Wang
- Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing, China.,Center of Epilepsy, Center for Brain Disorders Research, Capital Medical University, Beijing, China.,Center of Epilepsy, Beijing Institute of Brain Disorders, Beijing, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
| | - Shuli Liang
- Department of Functional Neurosurgery, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Guojun Zhang
- Department of Functional Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Xiaofeng Yang
- Neuroelectrophysiological Laboratory, Xuanwu Hospital, Capital Medical University, Beijing, China.,Center of Epilepsy, Center for Brain Disorders Research, Capital Medical University, Beijing, China.,Center of Epilepsy, Beijing Institute of Brain Disorders, Beijing, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
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30
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Inhibition and oscillations in the human brain tissue in vitro. Neurobiol Dis 2019; 125:198-210. [DOI: 10.1016/j.nbd.2019.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/22/2018] [Accepted: 02/07/2019] [Indexed: 01/22/2023] Open
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31
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Represa A. Why Malformations of Cortical Development Cause Epilepsy. Front Neurosci 2019; 13:250. [PMID: 30983952 PMCID: PMC6450262 DOI: 10.3389/fnins.2019.00250] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/04/2019] [Indexed: 12/13/2022] Open
Abstract
Malformations of cortical development (MCDs), a complex family of rare disorders, result from alterations of one or combined developmental steps, including progenitors proliferation, neuronal migration and differentiation. They are an important cause of childhood epilepsy and frequently associate cognitive deficits and behavioral alterations. Though the physiopathological mechanisms of epilepsy in MCD patients remain poorly elucidated, research during the past decade highlighted the contribution of some factors that will be reviewed in this paper and that include: (i) the genes that caused the malformation, that can be responsible for a significant reduction of inhibitory cells (e.g., ARX gene) or be inducing cell-autonomous epileptogenic changes in affected neurons (e.g., mutations on the mTOR pathway); (ii) the alteration of cortical networks development induced by the malformation that will also involve adjacent or distal cortical areas apparently sane so that the epileptogenic focus might be more extended that the malformation or even localized at distance from it; (iii) the normal developmental processes that would influence and determine the onset of epilepsy in MCD patients, particularly precocious in most of the cases.
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Affiliation(s)
- Alfonso Represa
- INSERM, Institut de Neurobiologie de la Méditerranée, Aix-Marseille University, Marseille, France
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32
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Blauwblomme T, Dossi E, Pellegrino C, Goubert E, Iglesias BG, Sainte-Rose C, Rouach N, Nabbout R, Huberfeld G. Gamma-aminobutyric acidergic transmission underlies interictal epileptogenicity in pediatric focal cortical dysplasia. Ann Neurol 2019; 85:204-217. [PMID: 30597612 DOI: 10.1002/ana.25403] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 12/21/2018] [Accepted: 12/21/2018] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Dysregulation of γ-aminobutyric acidergic (GABAergic) transmission has been reported in lesional acquired epilepsies (gliomas, hippocampal sclerosis). We investigated its involvement in a developmental disorder, human focal cortical dysplasia (FCD), focusing on chloride regulation driving GABAergic signals. METHODS In vitro recordings of 47 human cortical acute slices from 11 pediatric patients who received operations for FCD were performed on multielectrode arrays. GABAergic receptors and chloride regulators were pharmacologically modulated. Immunostaining for chloride cotransporter KCC2 and interneurons were performed on recorded slices to correlate electrophysiology and expression patterns. RESULTS FCD slices retain intrinsic epileptogenicity. Thirty-six of 47 slices displayed spontaneous interictal discharges, along with a pattern specific to the histological subtypes. Ictal discharges were induced in proepileptic conditions in 6 of 8 slices in the areas generating spontaneous interictal discharges, with a transition to seizure involving the emergence of preictal discharges. Interictal discharges were sustained by GABAergic signaling, as a GABAA receptor blocker stopped them in 2 of 3 slices. Blockade of NKCC1 Cl- cotransporters further controlled interictal discharges in 9 of 12 cases, revealing a Cl- dysregulation affecting actions of GABA. Immunohistochemistry highlighted decreased expression and changes in KCC2 subcellular localization and a decrease in the number of GAD67-positive interneurons in regions generating interictal discharges. INTERPRETATION Altered chloride cotransporter expression and changes in interneuron density in FCD may lead to paradoxical depolarization of pyramidal cells. Spontaneous interictal discharges are consequently mediated by GABAergic signals, and targeting chloride regulation in neurons may be considered for the development of new antiepileptic drugs. Ann Neurol 2019; 1-14 ANN NEUROL 2019;85:204-217.
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Affiliation(s)
- Thomas Blauwblomme
- APHP, Department of Pediatric Neurosurgery, Hospital Necker, Paris, France.,Université René Descartes. PRES Sorbonne Paris Cité, Paris, France.,INSERM U1129, Infantile Epilepsies and Brain Plasticity, Paris Descartes University, PRES Sorbonne Paris Cité, Paris, France
| | - Elena Dossi
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | | | | | - Beatriz Gal Iglesias
- Facultad de Ciencias Biomédicas y de la Salud, Universidad Europea, Madrid, Spain
| | - Christian Sainte-Rose
- APHP, Department of Pediatric Neurosurgery, Hospital Necker, Paris, France.,Université René Descartes. PRES Sorbonne Paris Cité, Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Rima Nabbout
- Université René Descartes. PRES Sorbonne Paris Cité, Paris, France.,APHP, Department of Neuropediatrics, Hospital Necker, Paris, France
| | - Gilles Huberfeld
- INSERM U1129, Infantile Epilepsies and Brain Plasticity, Paris Descartes University, PRES Sorbonne Paris Cité, Paris, France.,Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNR UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.,Sorbonne University, AP-HP, Department of Neurophysiology, La Pitié-Salpêtrière Hospital, Paris, France
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33
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Dixit AB, Sharma D, Tripathi M, Srivastava A, Paul D, Prakash D, Sarkar C, Kumar K, Banerjee J, Chandra PS. Genome-wide DNA Methylation and RNAseq Analyses Identify Aberrant Signalling Pathways in Focal Cortical Dysplasia (FCD) Type II. Sci Rep 2018; 8:17976. [PMID: 30568293 PMCID: PMC6299275 DOI: 10.1038/s41598-018-35892-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 10/01/2018] [Indexed: 01/26/2023] Open
Abstract
Focal cortical dysplasia (FCD) is one of the most common pathologies associated with drug-resistant epilepsy (DRE). The pharmacological targets remain obscured, as the molecular mechanisms underlying FCD are unclear. Implications of epigenetically modulated aberrant gene expression in disease progression are reported in various DRE pathologies except FCD. Here we performed genome-wide CpG-DNA methylation profiling by methylated DNA immunoprecipitation (MeDIP) microarray and RNA sequencing (RNAseq) on cortical tissues resected from FCD type II patients. A total of 19088 sites showed altered DNA methylation in all the CpG islands. Of these, 5725 sites were present in the promoter regions, of which 176 genes showed an inverse correlation between methylation and gene expression. Many of these 176 genes were found to belong to a cohesive network of physically interacting proteins linked to several cellular functions. Pathway analysis revealed significant enrichment of receptor tyrosine kinases (RTK), EGFR, PDGFRA, NTRK3, and mTOR signalling pathways. This is the first study that investigates the epigenetic signature associated with FCD type II pathology. The candidate genes and pathways identified in this study may play a crucial role in the regulation of the pathogenic mechanisms of epileptogenesis associated with FCD type II pathologies.
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Affiliation(s)
- Aparna Banerjee Dixit
- Center of Excellence for Epilepsy, A joint NBRC-AIIMS collaboration, NBRC, Manesar, India. .,Dr. B R Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India.
| | - Devina Sharma
- Center of Excellence for Epilepsy, A joint NBRC-AIIMS collaboration, NBRC, Manesar, India.,Department of Neurosurgery, AIIMS, New Delhi, India
| | - Manjari Tripathi
- Center of Excellence for Epilepsy, A joint NBRC-AIIMS collaboration, NBRC, Manesar, India.,Department of Neurology, AIIMS, New Delhi, India
| | | | - Debasmita Paul
- Center of Excellence for Epilepsy, A joint NBRC-AIIMS collaboration, NBRC, Manesar, India.,Department of Neurosurgery, AIIMS, New Delhi, India
| | - Deepak Prakash
- Department of Forensic Medicine and Toxicology, AIIMS, New Delhi, India
| | | | - Krishan Kumar
- Center of Excellence for Epilepsy, A joint NBRC-AIIMS collaboration, NBRC, Manesar, India.,Department of Neurosurgery, AIIMS, New Delhi, India
| | - Jyotirmoy Banerjee
- Center of Excellence for Epilepsy, A joint NBRC-AIIMS collaboration, NBRC, Manesar, India.,Department of Biophysics, AIIMS, New Delhi, India
| | - P Sarat Chandra
- Center of Excellence for Epilepsy, A joint NBRC-AIIMS collaboration, NBRC, Manesar, India. .,Department of Neurosurgery, AIIMS, New Delhi, India.
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34
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Wang Y, Wang Y, Chen Z. Double-edged GABAergic synaptic transmission in seizures: The importance of chloride plasticity. Brain Res 2018; 1701:126-136. [PMID: 30201259 DOI: 10.1016/j.brainres.2018.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 09/04/2018] [Accepted: 09/06/2018] [Indexed: 12/18/2022]
Abstract
GABAergic synaptic inhibition, which is a critical regulator of neuronal excitability, is closely involved in epilepsy. Interestingly, fast GABAergic transmission mediated by Cl- permeable GABAA receptors can bi-directionally exert both seizure-suppressing and seizure-promoting actions. Accumulating evidence suggests that chloride plasticity, the driving force of GABAA receptor-mediated synaptic transmission, contributes to the double-edged role of GABAergic synapses in seizures. Large amounts of Cl- influx can overwhelm Cl- extrusion during seizures not only in healthy tissue in a short-term "activity-dependent" manner, but also in chronic epilepsy in a long-term, irreversible "pathology-dependent" manner related to the dysfunction of two chloride transporters: the chloride importer NKCC1 and the chloride exporter KCC2. In this review, we address the importance of chloride plasticity for the "activity-dependent" and "pathology-dependent" mechanisms underlying epileptic events and provide possible directions for further research, which may be clinically important for the design of GABAergic synapse-targeted precise therapeutic interventions for epilepsy.
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Affiliation(s)
- Ying Wang
- Institute of Pharmacology & Toxicology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Yi Wang
- Institute of Pharmacology & Toxicology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Zhong Chen
- Institute of Pharmacology & Toxicology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China; Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
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35
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Ruffolo G, Cifelli P, Roseti C, Thom M, van Vliet EA, Limatola C, Aronica E, Palma E. A novel GABAergic dysfunction in human Dravet syndrome. Epilepsia 2018; 59:2106-2117. [DOI: 10.1111/epi.14574] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 09/11/2018] [Accepted: 09/11/2018] [Indexed: 01/09/2023]
Affiliation(s)
- Gabriele Ruffolo
- Department of Physiology and Pharmacology; Pasteur Institute-Cenci Bolognetti Foundation; Sapienza University of Rome; Rome Italy
| | - Pierangelo Cifelli
- Department of Physiology and Pharmacology; Pasteur Institute-Cenci Bolognetti Foundation; Sapienza University of Rome; Rome Italy
- IRCCS Neuromed; Pozzilli Italy
| | | | - Maria Thom
- Department of Clinical and Experimental Epilepsy; University College London Institute of Neurology; London UK
| | - Erwin A. van Vliet
- Department of (Neuro)Pathology; Amsterdam UMC; University of Amsterdam; Amsterdam Neuroscience; Amsterdam The Netherlands
- Center for Neuroscience; Swammerdam Institute for Life Sciences; University of Amsterdam; Amsterdam The Netherlands
| | - Cristina Limatola
- Department of Physiology and Pharmacology; Pasteur Institute-Cenci Bolognetti Foundation; Sapienza University of Rome; Rome Italy
- IRCCS Neuromed; Pozzilli Italy
| | - Eleonora Aronica
- Department of (Neuro)Pathology; Amsterdam UMC; University of Amsterdam; Amsterdam Neuroscience; Amsterdam The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN); Heemstede The Netherlands
| | - Eleonora Palma
- Department of Physiology and Pharmacology; Pasteur Institute-Cenci Bolognetti Foundation; Sapienza University of Rome; Rome Italy
- IRCCS San Raffaele Pisana; Rome Italy
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36
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BRAF somatic mutation contributes to intrinsic epileptogenicity in pediatric brain tumors. Nat Med 2018; 24:1662-1668. [PMID: 30224756 DOI: 10.1038/s41591-018-0172-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 07/27/2018] [Indexed: 12/21/2022]
Abstract
Pediatric brain tumors are highly associated with epileptic seizures1. However, their epileptogenic mechanisms remain unclear. Here, we show that the oncogenic BRAF somatic mutation p.Val600Glu (V600E) in developing neurons underlies intrinsic epileptogenicity in ganglioglioma, one of the leading causes of intractable epilepsy2. To do so, we developed a mouse model harboring the BRAFV600E somatic mutation during early brain development to reflect the most frequent mutation, as well as the origin and timing thereof. Therein, the BRAFV600E mutation arising in progenitor cells during brain development led to the acquisition of intrinsic epileptogenic properties in neuronal lineage cells, whereas tumorigenic properties were attributed to high proliferation of glial lineage cells. RNA sequencing analysis of patient brain tissues with the mutation revealed that BRAFV600E-induced epileptogenesis is mediated by RE1-silencing transcription factor (REST), which is a regulator of ion channels and neurotransmitter receptors associated with epilepsy. Moreover, we found that seizures in mice were significantly alleviated by an FDA-approved BRAFV600E inhibitor, vemurafenib, as well as various genetic inhibitions of Rest. Accordingly, this study provides direct evidence of a BRAF somatic mutation contributing to the intrinsic epileptogenicity in pediatric brain tumors and suggests that BRAF and REST could be treatment targets for intractable epilepsy.
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37
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Challenges in managing epilepsy associated with focal cortical dysplasia in children. Epilepsy Res 2018; 145:1-17. [DOI: 10.1016/j.eplepsyres.2018.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 04/30/2018] [Accepted: 05/12/2018] [Indexed: 12/15/2022]
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38
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Porcher C, Medina I, Gaiarsa JL. Mechanism of BDNF Modulation in GABAergic Synaptic Transmission in Healthy and Disease Brains. Front Cell Neurosci 2018; 12:273. [PMID: 30210299 PMCID: PMC6121065 DOI: 10.3389/fncel.2018.00273] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/06/2018] [Indexed: 12/18/2022] Open
Abstract
In the mature healthy mammalian neuronal networks, γ-aminobutyric acid (GABA) mediates synaptic inhibition by acting on GABAA and GABAB receptors (GABAAR, GABABR). In immature networks and during numerous pathological conditions the strength of GABAergic synaptic inhibition is much less pronounced. In these neurons the activation of GABAAR produces paradoxical depolarizing action that favors neuronal network excitation. The depolarizing action of GABAAR is a consequence of deregulated chloride ion homeostasis. In addition to depolarizing action of GABAAR, the GABABR mediated inhibition is also less efficient. One of the key molecules regulating the GABAergic synaptic transmission is the brain derived neurotrophic factor (BDNF). BDNF and its precursor proBDNF, can be released in an activity-dependent manner. Mature BDNF operates via its cognate receptors tropomyosin related kinase B (TrkB) whereas proBDNF binds the p75 neurotrophin receptor (p75NTR). In this review article, we discuss recent finding illuminating how mBDNF-TrkB and proBDNF-p75NTR signaling pathways regulate GABA related neurotransmission under physiological conditions and during epilepsy.
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Affiliation(s)
- Christophe Porcher
- Aix Marseille University, Marseille, France.,Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Marseille, France.,Institut de Neurobiologie de la Méditerranée (INMED), Marseille, France
| | - Igor Medina
- Aix Marseille University, Marseille, France.,Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Marseille, France.,Institut de Neurobiologie de la Méditerranée (INMED), Marseille, France
| | - Jean-Luc Gaiarsa
- Aix Marseille University, Marseille, France.,Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Marseille, France.,Institut de Neurobiologie de la Méditerranée (INMED), Marseille, France
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39
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Amadeo A, Coatti A, Aracri P, Ascagni M, Iannantuoni D, Modena D, Carraresi L, Brusco S, Meneghini S, Arcangeli A, Pasini ME, Becchetti A. Postnatal Changes in K +/Cl - Cotransporter-2 Expression in the Forebrain of Mice Bearing a Mutant Nicotinic Subunit Linked to Sleep-Related Epilepsy. Neuroscience 2018; 386:91-107. [PMID: 29949744 DOI: 10.1016/j.neuroscience.2018.06.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 06/14/2018] [Accepted: 06/18/2018] [Indexed: 12/13/2022]
Abstract
The Na+/K+/Cl- cotransporter-1 (NKCC1) and the K+/Cl- cotransporter-2 (KCC2) set the transmembrane Cl- gradient in the brain, and are implicated in epileptogenesis. We studied the postnatal distribution of NKCC1 and KCC2 in wild-type (WT) mice, and in a mouse model of sleep-related epilepsy, carrying the mutant β2-V287L subunit of the nicotinic acetylcholine receptor (nAChR). In WT neocortex, immunohistochemistry showed a wide distribution of NKCC1 in neurons and astrocytes. At birth, KCC2 was localized in neuronal somata, whereas at subsequent stages it was mainly found in the somatodendritic compartment. The cotransporters' expression was quantified by densitometry in the transgenic strain. KCC2 expression increased during the first postnatal weeks, while the NKCC1 amount remained stable, after birth. In mice expressing β2-V287L, the KCC2 amount in layer V of prefrontal cortex (PFC) was lower than in the control littermates at postnatal day 8 (P8), with no concomitant change in NKCC1. Consistently, the GABAergic excitatory to inhibitory switch was delayed in PFC layer V of mice carrying β2-V287L. At P60, the amount of KCC2 was instead higher in mice bearing the transgene. Irrespective of genotype, NKCC1 and KCC2 were abundantly expressed in the neuropil of most thalamic nuclei since birth. However, KCC2 expression decreased by P60 in the reticular nucleus, and more so in mice expressing β2-V287L. Therefore, a complex regulatory interplay occurs between heteromeric nAChRs and KCC2 in postnatal forebrain. The pathogenetic effect of β2-V287L may depend on altered KCC2 amounts in PFC during synaptogenesis, as well as in mature thalamocortical circuits.
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Affiliation(s)
- Alida Amadeo
- Department of Biosciences, University of Milano, Via Celoria, 26, 20133 Milano, Italy.
| | - Aurora Coatti
- Department of Biotechnology and Biosciences, and NeuroMI-Milan Center of Neuroscience, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
| | - Patrizia Aracri
- Department of Biotechnology and Biosciences, and NeuroMI-Milan Center of Neuroscience, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
| | - Miriam Ascagni
- Department of Biosciences, University of Milano, Via Celoria, 26, 20133 Milano, Italy.
| | - Davide Iannantuoni
- Department of Biosciences, University of Milano, Via Celoria, 26, 20133 Milano, Italy.
| | - Debora Modena
- Department of Biosciences, University of Milano, Via Celoria, 26, 20133 Milano, Italy.
| | - Laura Carraresi
- Dival Toscana Srl, Via Madonna del Piano, 6 - 50019 Sesto Fiorentino, Firenze, Italy.
| | - Simone Brusco
- Department of Biotechnology and Biosciences, and NeuroMI-Milan Center of Neuroscience, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
| | - Simone Meneghini
- Department of Biotechnology and Biosciences, and NeuroMI-Milan Center of Neuroscience, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
| | - Annarosa Arcangeli
- Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50134 Firenze, Italy.
| | - Maria Enrica Pasini
- Department of Biosciences, University of Milano, Via Celoria, 26, 20133 Milano, Italy.
| | - Andrea Becchetti
- Department of Biotechnology and Biosciences, and NeuroMI-Milan Center of Neuroscience, University of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
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40
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Di Cristo G, Awad PN, Hamidi S, Avoli M. KCC2, epileptiform synchronization, and epileptic disorders. Prog Neurobiol 2018; 162:1-16. [DOI: 10.1016/j.pneurobio.2017.11.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 11/09/2017] [Accepted: 11/28/2017] [Indexed: 12/31/2022]
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41
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Kielbinski M, Gzielo K, Soltys Z. Review: Roles for astrocytes in epilepsy: insights from malformations of cortical development. Neuropathol Appl Neurobiol 2018; 42:593-606. [PMID: 27257021 DOI: 10.1111/nan.12331] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 05/25/2016] [Accepted: 06/03/2016] [Indexed: 12/25/2022]
Abstract
Malformations of cortical development (MCDs), such as cortical dysplasia and tuberous sclerosis complex, are common causes of intractable epilepsy, especially in paediatric patients. Recently, mounting evidence points to a common pathology of these disorders. Hyperactivation of mammalian target of rapamycin (mTOR) has been proposed as a central mechanism in most, if not all, MCDs. The transition from mTOR hyperactivation and cellular abnormalities to large-scale functional changes and seizure is, however, not fully understood. In this article we set out to review currently available information regarding MCD pathology, focusing on glial cells - especially astrocytes - and their interactions with the brain vascular system. A large body of evidence points to these elements as potential targets in MCD. Here, we attempt to provide a review of this evidence and propose some hypotheses regarding the possible chain of events linking primary glial dysfunction and epilepsy. We focus on extracellular matrix remodelling, blood-brain barrier leakage and failure of astrocyte-dependent removal of extracellular debris. We posit that the failure of these systems results in a chronically pro-inflammatory environment, maintaining local astrocytes in a state of gliosis, with increased susceptibility to seizures as a consequence.
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Affiliation(s)
- M Kielbinski
- Department of Neuroanatomy, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - K Gzielo
- Department of Neuroanatomy, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Z Soltys
- Department of Neuroanatomy, Institute of Zoology, Jagiellonian University, Krakow, Poland
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42
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Ye H, Kaszuba S. Inhibitory or excitatory? Optogenetic interrogation of the functional roles of GABAergic interneurons in epileptogenesis. J Biomed Sci 2017; 24:93. [PMID: 29202749 PMCID: PMC5715558 DOI: 10.1186/s12929-017-0399-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/28/2017] [Indexed: 01/22/2023] Open
Abstract
Alteration in the excitatory/inhibitory neuronal balance is believed to be the underlying mechanism of epileptogenesis. Based on this theory, GABAergic interneurons are regarded as the primary inhibitory neurons, whose failure of action permits hyperactivity in the epileptic circuitry. As a consequence, optogenetic excitation of GABAergic interneurons is widely used for seizure suppression. However, recent evidence argues for the context-dependent, possibly “excitatory” roles that GABAergic cells play in epileptic circuitry. We reviewed current optogenetic approaches that target the “inhibitory” roles of GABAergic interneurons for seizure control. We also reviewed interesting evidence that supports the “excitatory” roles of GABAergic interneurons in epileptogenesis. GABAergic interneurons can provide excitatory effects to the epileptic circuits via several distinct neurological mechanisms. (1) GABAergic interneurons can excite postsynaptic neurons, due to the raised reversal potential of GABA receptors in the postsynaptic cells. (2) Continuous activity in GABAergic interneurons could lead to transient GABA depletion, which prevents their inhibitory effect on pyramidal cells. (3) GABAergic interneurons can synchronize network activity during seizure. (4) Some GABAergic interneurons inhibit other interneurons, causing disinhibition of pyramidal neurons and network hyperexcitability. The dynamic, context-dependent role that GABAergic interneurons play in seizure requires further investigation of their functions at single cell and circuitry level. New optogenetic protocols that target GABAergic inhibition should be explored for seizure suppression.
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Affiliation(s)
- Hui Ye
- Department of Biology, Loyola University Chicago, Quinlan Life Sciences Education and Research Center, 1032 W. Sheridan Rd, Chicago, IL, 60660, USA.
| | - Stephanie Kaszuba
- Department of Biology, Loyola University Chicago, Quinlan Life Sciences Education and Research Center, 1032 W. Sheridan Rd, Chicago, IL, 60660, USA
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43
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Thom M, Liu J, Bongaarts A, Reinten RJ, Paradiso B, Jäger HR, Reeves C, Somani A, An S, Marsdon D, McEvoy A, Miserocchi A, Thorne L, Newman F, Bucur S, Honavar M, Jacques T, Aronica E. Multinodular and vacuolating neuronal tumors in epilepsy: dysplasia or neoplasia? Brain Pathol 2017; 28:155-171. [PMID: 28833756 PMCID: PMC5887881 DOI: 10.1111/bpa.12555] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 06/27/2017] [Accepted: 08/01/2017] [Indexed: 12/28/2022] Open
Abstract
Multinodular and vacuolating neuronal tumor (MVNT) is a new pattern of neuronal tumour included in the recently revised WHO 2016 classification of tumors of the CNS. There are 15 reports in the literature to date. They are typically associated with late onset epilepsy and a neoplastic vs. malformative biology has been questioned. We present a series of ten cases and compare their pathological and genetic features to better characterized epilepsy‐associated malformations including focal cortical dysplasia type II (FCDII) and low‐grade epilepsy‐associated tumors (LEAT). Clinical and neuroradiology data were reviewed and a broad immunohistochemistry panel was applied to explore neuronal and glial differentiation, interneuronal populations, mTOR pathway activation and neurodegenerative changes. Next generation sequencing was performed for targeted multi‐gene analysis to identify mutations common to epilepsy lesions including FCDII and LEAT. All of the surgical cases in this series presented with seizures, and were located in the temporal lobe. There was a lack of any progressive changes on serial pre‐operative MRI and a mean age at surgery of 45 years. The vacuolated cells of the lesion expressed mature neuronal markers (neurofilament/SMI32, MAP2, synaptophysin). Prominent labelling of the lesional cells for developmentally regulated proteins (OTX1, TBR1, SOX2, MAP1b, CD34, GFAPδ) and oligodendroglial lineage markers (OLIG2, SMI94) was observed. No mutations were detected in the mTOR pathway genes, BRAF, FGFR1 or MYB. Clinical, pathological and genetic data could indicate that MVNT aligns more with a malformative lesion than a true neoplasm with origin from a progenitor neuro‐glial cell type showing aberrant maturation.
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Affiliation(s)
- Maria Thom
- Departments of Clinical and Experimental Epilepsy and Neuropathology, UCL Institute of Neurology and the National Hospital for Neurology and Neurosurgery, Queen Square, London WCN1BG, UK
| | - Joan Liu
- Departments of Clinical and Experimental Epilepsy and Neuropathology, UCL Institute of Neurology and the National Hospital for Neurology and Neurosurgery, Queen Square, London WCN1BG, UK
| | - Anika Bongaarts
- Department of (Neuro)Pathology, Academic Medical Center, Amsterdam, The Netherlands
| | - Roy J Reinten
- Department of (Neuro)Pathology, Academic Medical Center, Amsterdam, The Netherlands
| | - Beatrice Paradiso
- Departments of Clinical and Experimental Epilepsy and Neuropathology, UCL Institute of Neurology and the National Hospital for Neurology and Neurosurgery, Queen Square, London WCN1BG, UK.,Cardiovascular Pathology Unit, Department of Cardiac, Thoracic and Vascular Sciences University of Padua Medical School, Padova, Italy
| | - Hans Rolf Jäger
- Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Cheryl Reeves
- Departments of Clinical and Experimental Epilepsy and Neuropathology, UCL Institute of Neurology and the National Hospital for Neurology and Neurosurgery, Queen Square, London WCN1BG, UK
| | - Alyma Somani
- Departments of Clinical and Experimental Epilepsy and Neuropathology, UCL Institute of Neurology and the National Hospital for Neurology and Neurosurgery, Queen Square, London WCN1BG, UK
| | - Shu An
- Departments of Clinical and Experimental Epilepsy and Neuropathology, UCL Institute of Neurology and the National Hospital for Neurology and Neurosurgery, Queen Square, London WCN1BG, UK
| | - Derek Marsdon
- Departments of Clinical and Experimental Epilepsy and Neuropathology, UCL Institute of Neurology and the National Hospital for Neurology and Neurosurgery, Queen Square, London WCN1BG, UK
| | - Andrew McEvoy
- Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Anna Miserocchi
- Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Lewis Thorne
- Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - Fay Newman
- Neurosurgery Department, Brighton and Sussex University Hospitals, Brighton, UK
| | - Sorin Bucur
- Neurosurgery Department, Brighton and Sussex University Hospitals, Brighton, UK
| | - Mrinalini Honavar
- Department of Anatomic Pathology, Hospital Pedro Hispano, Matosinhos, Portugal
| | - Tom Jacques
- Neuropathology Department, Great Ormond Street Hospital, London, UK
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, Amsterdam, The Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
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Hartmann AM, Pisella LI, Medina I, Nothwang HG. Molecular cloning and biochemical characterization of two cation chloride cotransporter subfamily members of Hydra vulgaris. PLoS One 2017; 12:e0179968. [PMID: 28662098 PMCID: PMC5491111 DOI: 10.1371/journal.pone.0179968] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 06/07/2017] [Indexed: 01/21/2023] Open
Abstract
Cation Chloride Cotransporters (CCCs) comprise secondary active membrane proteins mainly mediating the symport of cations (Na+, K+) coupled with chloride (Cl−). They are divided into K+-Cl− outward transporters (KCCs), the Na+-K+-Cl− (NKCCs) and Na+-Cl− (NCCs) inward transporters, the cation chloride cotransporter interacting protein CIP1, and the polyamine transporter CCC9. KCCs and N(K)CCs are established in the genome since eukaryotes and metazoans, respectively. Most of the physiological and functional data were obtained from vertebrate species. To get insights into the basal functional properties of KCCs and N(K)CCs in the metazoan lineage, we cloned and characterized KCC and N(K)CC from the cnidarian Hydra vulgaris. HvKCC is composed of 1,032 amino-acid residues. Functional analyses revealed that hvKCC mediates a Na+-independent, Cl− and K+ (Tl+)-dependent cotransport. The classification of hvKCC as a functional K-Cl cotransporter is furthermore supported by phylogenetic analyses and a similar structural organization. Interestingly, recently obtained physiological analyses indicate a role of cnidarian KCCs in hyposmotic volume regulation of nematocytes. HvN(K)CC is composed of 965 amino-acid residues. Phylogenetic analyses and structural organization suggest that hvN(K)CC is a member of the N(K)CC subfamily. However, no inorganic ion cotransport function could be detected using different buffer conditions. Thus, hvN(K)CC is a N(K)CC subfamily member without a detectable inorganic ion cotransporter function. Taken together, the data identify two non-bilaterian solute carrier 12 (SLC12) gene family members, thereby paving the way for a better understanding of the evolutionary paths of this important cotransporter family.
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Affiliation(s)
- Anna-Maria Hartmann
- Neurogenetics Group, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Center for Neuroscience, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- * E-mail:
| | | | | | - Hans Gerd Nothwang
- Neurogenetics Group, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Center for Neuroscience, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Cluster of Excellence Hearing4All, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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Prieto-Martín AI, Aroca-Aguilar JD, Sánchez-Sánchez F, Muñoz LJ, López DE, Escribano J, de Cabo C. Molecular and neurochemical substrates of the audiogenic seizure strains: The GASH:Sal model. Epilepsy Behav 2017; 71:218-225. [PMID: 26071997 DOI: 10.1016/j.yebeh.2015.05.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/12/2015] [Accepted: 05/14/2015] [Indexed: 01/24/2023]
Abstract
PURPOSE Animal models of audiogenic epilepsy are useful tools to understand the mechanisms underlying human reflex epilepsies. There is accumulating evidence regarding behavioral, anatomical, electrophysiological, and genetic substrates of audiogenic seizure strains, but there are still aspects concerning their neurochemical basis that remain to be elucidated. Previous studies have shown the involved of γ-amino butyric acid (GABA) in audiogenic seizures. The aim of our research was to clarify the role of the GABAergic system in the generation of epileptic seizures in the genetic audiogenic seizure-prone hamster (GASH:Sal) strain. MATERIAL AND METHODS We studied the K+/Cl- cotransporter KCC2 and β2-GABAA-type receptor (GABAAR) and β3-GABAAR subunit expressions in the GASH:Sal both at rest and after repeated sound-induced seizures in different brain regions using the Western blot technique. We also sequenced the coding region for the KCC2 gene both in wild- type and GASH:Sal hamsters. RESULTS Lower expression of KCC2 protein was found in GASH:Sal when compared with controls at rest in several brain areas: hippocampus, cortex, cerebellum, hypothalamus, pons-medulla, and mesencephalon. Repeated induction of seizures caused a decrease in KCC2 protein content in the inferior colliculus and hippocampus and an increase in the pons-medulla. When compared to controls, the basal β2-GABAAR subunit in the GASH:Sal was overexpressed in the inferior colliculus, rest of the mesencephalon, and cerebellum, whereas basal β3 subunit levels were lower in the inferior colliculus and rest of the mesencephalon. Repeated seizures increased β2 both in the inferior colliculus and in the hypothalamus and β3 in the hypothalamus. No differences in the KCC2 gene-coding region were found between GASH:Sal and wild-type hamsters. CONCLUSIONS These data indicate that GABAergic system functioning is impaired in the GASH:Sal strain, and repeated seizures seem to aggravate this dysfunction. These results have potential clinical relevance and support the validity of employing the GASH:Sal strain as a model to study the neurochemistry of genetic reflex epilepsy. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic".
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Affiliation(s)
- Ana I Prieto-Martín
- Research Department, Neuropsychopharmacology Unit, Albacete General Hospital, 37 Hermanos Falcó Street, Albacete E-02006, Spain.
| | - J Daniel Aroca-Aguilar
- Department of Genetics, Faculty of Medicine, University of Castilla-La Mancha, 14 Almansa Street, Albacete E-02006, Spain.
| | - Francisco Sánchez-Sánchez
- Department of Genetics, Faculty of Medicine, University of Castilla-La Mancha, 14 Almansa Street, Albacete E-02006, Spain.
| | - Luis J Muñoz
- INCYL, University of Salamanca, 1 Pintor Gallego Street, Salamanca E-37007, Spain.
| | - Dolores E López
- INCYL, University of Salamanca, 1 Pintor Gallego Street, Salamanca E-37007, Spain.
| | - Julio Escribano
- Department of Genetics, Faculty of Medicine, University of Castilla-La Mancha, 14 Almansa Street, Albacete E-02006, Spain.
| | - Carlos de Cabo
- Research Department, Neuropsychopharmacology Unit, Albacete General Hospital, 37 Hermanos Falcó Street, Albacete E-02006, Spain.
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Sedmak G, Jovanov-Milošević N, Puskarjov M, Ulamec M, Krušlin B, Kaila K, Judaš M. Developmental Expression Patterns of KCC2 and Functionally Associated Molecules in the Human Brain. Cereb Cortex 2016; 26:4574-4589. [PMID: 26428952 DOI: 10.1093/cercor/bhv218] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Work on rodents demonstrated that steep upregulation of KCC2, a neuron-specific Cl- extruder of cation-chloride cotransporter (CCC) family, commences in supraspinal structures at around birth, leading to establishment of hyperpolarizing GABAergic responses. We describe spatiotemporal expression profiles of the entire CCC family in human brain. KCC2 mRNA was observed already at 10th postconceptional week (PCW) in amygdala, cerebellum, and thalamus. KCC2-immunoreactive (KCC2-ir) neurons were abundant in subplate at 18 PCW. By 25 PCW, numerous subplate and cortical plate neurons became KCC2-ir. The mRNA expression profiles of α- and β-isoforms of Na-K ATPase, which fuels cation-chloride cotransport, as well of tropomyosin receptor kinase B (TrkB), which promotes developmental upregulation of KCC2, were consistent with data from studies on rodents about their interactions with KCC2. Thus, in human brain, expression of KCC2 and its functionally associated proteins begins in early fetal period. Our work facilitates translation of results on CCC functions from animal studies to human and refutes the view that poor efficacy of anticonvulsants in the term human neonate is attributable to the lack of KCC2. We propose that perinatally low threshold for activation of Ca2+-dependent protease calpain renders neonates susceptible to downregulation of KCC2 by traumatic events, such as perinatal hypoxia ischemia.
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Affiliation(s)
| | | | - Martin Puskarjov
- Department of Biosciences and Neuroscience Center, University of Helsinki, Viikinkaari 1, Helsinki FI-00014, Finland
| | - Monika Ulamec
- Department of Pathology, Clinical Hospital Center Sisters of Mercy, University of Zagreb School of Medicine, Zagreb 10 000, Croatia
| | - Božo Krušlin
- Department of Pathology, Clinical Hospital Center Sisters of Mercy, University of Zagreb School of Medicine, Zagreb 10 000, Croatia
| | - Kai Kaila
- Department of Biosciences and Neuroscience Center, University of Helsinki, Viikinkaari 1, Helsinki FI-00014, Finland
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Kahle KT, Khanna AR, Duan J, Staley KJ, Delpire E, Poduri A. The KCC2 Cotransporter and Human Epilepsy: Getting Excited About Inhibition. Neuroscientist 2016; 22:555-562. [PMID: 27130838 DOI: 10.1177/1073858416645087] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The cation-Cl- cotransporter KCC2, encoded by SLC12A5, is required for the emergence and maintenance of GABAergic fast synaptic inhibition in organisms across evolution. These findings have suggested that KCC2 deficiency might play a role in the pathogenesis human epilepsy, but this has only recently been substantiated by two lines of genetic evidence. The first is the discovery of heterozygous missense polymorphisms in SLC12A5, causing decreased KCC2-dependent Cl- extrusion capacity, in an Australian family with inherited febrile seizures and in a French-Canadian cohort with severe genetic generalized epilepsy (GGE). The second is the discovery of recessive loss-of-function mutations in SLC12A5 in patients with a severe, early-onset Mendelian disease termed "epilepsy of infancy with migrating focal seizures" (EIMFS). These findings collectively support the paradigm that precisely regulated KCC2 activity is required for synaptic inhibition in humans, and that genetically encoded impairment of KCC2 function, due to effects on gene dosage, intrinsic activity, or extrinsic regulation, can influence epilepsy phenotypes in patients. Accordingly, KCC2 could be a target for a novel antiepileptic strategies that aims to restore GABA inhibition by facilitating Cl- extrusion. Such drugs could have relevance for pharmaco-resistant epilepsies and possibly other diseases characterized by synaptic hyperexcitability, such as the spectrum autism disorders.
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Affiliation(s)
- Kristopher T Kahle
- Departments of Neurosurgery, Pediatrics, and Cellular and Molecular Physiology, Yale Program in Neurogenetics, and Centers for Mendelian Genomics, Yale University School of Medicine, New Haven, CT, USA
| | - Arjun R Khanna
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - JingJing Duan
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Kevin J Staley
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Annapurna Poduri
- Division of Epilepsy and Clinical Electrophysiology, Department of Neurology, Boston Children's Hospital, Boston, MA, USA
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Zhou XW, Wang X, Yang Y, Luo JW, Dong H, Liu YH, Mao Q. Biomarkers related with seizure risk in glioma patients: A systematic review. Clin Neurol Neurosurg 2016; 151:113-119. [PMID: 27821299 DOI: 10.1016/j.clineuro.2016.10.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 10/03/2016] [Indexed: 02/05/2023]
Abstract
Increasing evidence indicates that genetic biomarkers play important roles in the development of glioma-associated seizures. Thus, we performed a systematic review to summarise biomarkers that are associated with seizures in glioma patients. An electronic literature search of public databases (PubMed, Embase and Medline) was performed using the keywords glioma, seizure and epilepsy. A totall of 26 eligible studies with 2224 cases were included in this systematic review of publications to 20 June, 2016. Genetic biomarkers such as isocitrate dehydrogenase 1 (IDH1) mutations, low expression of excitatory amino acid transporter 2 (EAAT2), high xCT expression, overexpression of adenosine kinase (ADK) and low expression of very large G-protein-coupled receptor-1 (VLGR1) are primarily involved in synaptic transmission, whereas BRAF mutations, epidermal growth factor receptor (EGFR) amplification, miR-196b expression and low ki-67 expression are associated with regulation of cell proliferation. However, there is limited evidence regarding the roles of RAD50 interactor 1 (RINT1) and olig2 in epileptogenesis among glioma patients. Glioma-related seizure was related to the dysfunction of tumor microenvironment. Our findings may provide new mechanistic insights into targeted therapy for glioma-related seizures and may result in the development of multi-target therapies.
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Affiliation(s)
- Xing-Wang Zhou
- Department of Neurosurgery, West China Hospital, Si Chuan University, Chengdu 610041, China
| | - Xiang Wang
- Department of Neurosurgery, West China Hospital, Si Chuan University, Chengdu 610041, China
| | - Yuan Yang
- Department of Neurosurgery, West China Hospital, Si Chuan University, Chengdu 610041, China
| | - Jie-Wen Luo
- Department of Neurosurgery, West China Hospital, Si Chuan University, Chengdu 610041, China
| | - Hui Dong
- Department of Neurosurgery, West China Hospital, Si Chuan University, Chengdu 610041, China
| | - Yan-Hui Liu
- Department of Neurosurgery, West China Hospital, Si Chuan University, Chengdu 610041, China
| | - Qing Mao
- Department of Neurosurgery, West China Hospital, Si Chuan University, Chengdu 610041, China.
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Functional aspects of early brain development are preserved in tuberous sclerosis complex (TSC) epileptogenic lesions. Neurobiol Dis 2016; 95:93-101. [DOI: 10.1016/j.nbd.2016.07.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/05/2016] [Accepted: 07/13/2016] [Indexed: 02/04/2023] Open
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50
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MacKenzie G, O'Toole KK, Moss SJ, Maguire J. Compromised GABAergic inhibition contributes to tumor-associated epilepsy. Epilepsy Res 2016; 126:185-96. [PMID: 27513374 PMCID: PMC5308901 DOI: 10.1016/j.eplepsyres.2016.07.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/02/2016] [Accepted: 07/26/2016] [Indexed: 10/21/2022]
Abstract
Glioblastoma Multiforme (GBM) is the most common form of primary brain tumor with 30-50% of patients presenting with epilepsy. These tumor-associated seizures are often resistant to traditional antiepileptic drug treatment and persist after tumor resection. This suggests that changes in the peritumoral tissue underpin epileptogenesis. It is known that glioma cells extrude pathological concentrations of glutamate which is thought to play a role in tumor progression and the development of epilepsy. Given that pathological concentrations of glutamate have been shown to dephosphorylate and downregulate the potassium chloride cotransporter KCC2, we hypothesized that glioma-induced alterations in KCC2 in the peritumoral region may play a role in tumor-associated epilepsy. Consistent with this hypothesis, we observe a decrease in total KCC2 expression and a dephosphorylation of KCC2 at residue Ser940 in a glioma model which exhibits hyperexcitability and the development of spontaneous seizures. To determine whether the reduction of KCC2 could potentially contribute to tumor-associated epilepsy, we generated mice with a focal knockdown of KCC2 by injecting AAV2-Cre-GFP into the cortex of floxed KCC2 mice. The AAV2-Cre-mediated knockdown of KCC2 was sufficient to induce the development of spontaneous seizures. Further, blocking NKCC1 with bumetanide to offset the loss of KCC2 reduced the seizure susceptibility in glioma-implanted mice. These findings support a mechanism of tumor-associated epilepsy involving downregulation of KCC2 in the peritumoral region leading to compromised GABAergic inhibition and suggest that modulating chloride homeostasis may be useful for seizure control.
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Affiliation(s)
- Georgina MacKenzie
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Kate K O'Toole
- Training in Education and Critical Research Skills (TEACRS) Program, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Stephen J Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Jamie Maguire
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, United States.
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