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Berasain L, Beati P, Trigila AP, Rubinstein M, Franchini LF. Accelerated evolution in the human lineage led to gain and loss of transcriptional enhancers in the RBFOX1 locus. SCIENCE ADVANCES 2024; 10:eadl1049. [PMID: 38924416 PMCID: PMC11204294 DOI: 10.1126/sciadv.adl1049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 05/22/2024] [Indexed: 06/28/2024]
Abstract
A long-standing goal of evolutionary biology is to decode how changes in gene regulatory networks contribute to human-specific traits. Human accelerated regions (HARs) are prime candidates for driving gene regulatory modifications in human development. The RBFOX1 locus is densely populated with HARs, providing a set of potential regulatory elements that could have changed its expression in the human lineage. Here, we examined the role of RBFOX1-HARs using transgenic zebrafish reporter assays and identified 15 transcriptional enhancers that are active in the developing nervous system, 9 of which displayed differential activity between the human and chimpanzee sequences. The engineered loss of two selected RBFOX1-HARs in knockout mouse models modified Rbfox1 expression at specific developmental stages and tissues in the brain, influencing the expression and splicing of a high number of Rbfox1 target genes. Our results provided insight into the spatial and temporal changes in gene expression driven by RBFOX1-HARs.
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Affiliation(s)
- Lara Berasain
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) “Dr. Hector N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428, Argentina
| | - Paula Beati
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) “Dr. Hector N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428, Argentina
| | - Anabella P. Trigila
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) “Dr. Hector N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428, Argentina
| | - Marcelo Rubinstein
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) “Dr. Hector N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428, Argentina
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - Lucía F. Franchini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) “Dr. Hector N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428, Argentina
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Zhang J, Zou L, Tan F, Wang H, Wen Z, Wang H, Li L. Screening of co-expressed genes in hypopharyngeal carcinoma with esophageal carcinoma based on RNA sequencing and Clinical Research. Sci Rep 2024; 14:13796. [PMID: 38877096 PMCID: PMC11178892 DOI: 10.1038/s41598-024-64162-w] [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: 12/20/2023] [Accepted: 06/05/2024] [Indexed: 06/16/2024] Open
Abstract
To explore the hub comorbidity genes and potential pathogenic mechanisms of hypopharyngeal carcinoma with esophageal carcinoma, and evaluate their diagnostic value for hypopharyngeal carcinoma with co-morbid esophageal carcinoma. We performed gene sequencing on tumor tissues from 6 patients with hypopharyngeal squamous cell carcinoma with esophageal squamous cell carcinoma (hereafter referred to as "group A") and 6 patients with pure hypopharyngeal squamous cell carcinoma (hereafter referred to as "group B"). We analyzed the mechanism of hub genes in the development and progression of hypopharyngeal squamous cell carcinoma with esophageal squamous cell carcinoma through bioinformatics, and constructed an ROC curve and Nomogram prediction model to analyze the value of hub genes in clinical diagnosis and treatment. 44,876 genes were sequenced in 6 patients with group A and 6 patients with group B. Among them, 76 genes showed significant statistical differences between the group A and the group B.47 genes were expressed lower in the group A than in the group B, and 29 genes were expressed higher. The top five hub genes were GABRG2, CACNA1A, CNTNAP2, NOS1, and SCN4B. GABRG2, CNTNAP2, and SCN4B in the hub genes have high diagnostic value in determining whether hypopharyngeal carcinoma patients have combined esophageal carcinoma (AUC: 0.944, 0.944, 0.972). These genes could possibly be used as potential molecular markers for assessing the risk of co-morbidity of hypopharyngeal carcinoma combined with esophageal carcinoma.
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Affiliation(s)
- Jianing Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, Central Hospital of Chaoyang, Liaoning, 122000, China
| | - Liangyu Zou
- Department of Otorhinolaryngology Head and Neck Surgery, Central Hospital of Chaoyang, Liaoning, 122000, China
| | - Fuxian Tan
- Department of Otorhinolaryngology Head and Neck Surgery, Central Hospital of Chaoyang, Liaoning, 122000, China
| | - Hongmin Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Central Hospital of Chaoyang, Liaoning, 122000, China
| | - Zhenlei Wen
- Department of Otorhinolaryngology Head and Neck Surgery, Central Hospital of Chaoyang, Liaoning, 122000, China
| | - Hongmei Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Central Hospital of Chaoyang, Liaoning, 122000, China
| | - Lianhe Li
- Department of Otorhinolaryngology Head and Neck Surgery, Central Hospital of Chaoyang, Liaoning, 122000, China.
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Jiang YL, Xia L, Zhao JJ, Zhou HM, Mi D, Wang X, Wang YY, Song CG, Jiang W. Mice harboring the T316N variant in the GABA AR γ 2 subunit exhibit sleep-related hypermotor epilepsy phenotypes and hypersynchronization in the thalamocortical pathway. Exp Neurol 2024; 376:114775. [PMID: 38604438 DOI: 10.1016/j.expneurol.2024.114775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 03/27/2024] [Accepted: 04/06/2024] [Indexed: 04/13/2024]
Abstract
OBJECTIVE Sleep-related hypermotor epilepsy (SHE) is a focal epilepsy syndrome characterized by seizures that predominantly occur during sleep. The pathogenesis of these seizures remains unclear. We previously detected rare variants in GABRG2, which encodes the γ2 subunit of γ-aminobutyric acid type A receptor (GABAAR), in patients with SHE and demonstrated that these variants impaired GABAAR function in vitro. However, the mechanisms by which GABRG2 variants contribute to seizure attacks during sleep remain unclear. METHODS In this study, we designed a knock-in (KI) mouse expressing the mouse Gabrg2 T316N variant, corresponding to human GABRG2 T317N variant, using CRISPR/Cas9. Continuous video-electroencephalogram monitoring and in vivo multichannel electrophysiological recordings were performed to explore seizure susceptibility to pentylenetetrazol (PTZ), alterations in the sleep-wake cycle, spontaneous seizure patterns, and synchronized activity in the motor thalamic nuclei (MoTN) and secondary motor cortex (M2). Circadian variations in the expression of total, membrane-bound, and synaptic GABAAR subunits were also investigated. RESULTS No obvious changes in gross morphology were detected in Gabrg2T316N/+ mice compared to their wild-type (Gabrg2+/+) littermates. Gabrg2T316N/+ mice share key phenotypes with patients, including sleep fragmentation and spontaneous seizures during sleep. Gabrg2T316N/+ mice showed increased susceptibility to PTZ-induced seizures and higher mortality after seizures. Synchronization of the local field potentials between the MoTN and M2 was abnormally enhanced in Gabrg2T316N/+ mice during light phase, when sleep dominates, accompanied by increased local activities in the MoTN and M2. Interestingly, in Gabrg2+/+ mice, GABAAR γ2 subunits showed a circadian increase on the neuronal membrane and synaptosomes in the transition from dark phase to light phase, which was absent in Gabrg2T316N/+ mice. CONCLUSION We generated a new SHE mouse model and provided in vivo evidence that rare variants of GABRG2 contribute to seizure attacks during sleep in SHE.
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Affiliation(s)
- Yong-Li Jiang
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Liang Xia
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Jing-Jing Zhao
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Hui-Min Zhou
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Dan Mi
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Xuan Wang
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Yuan-Yuan Wang
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Chang-Geng Song
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
| | - Wen Jiang
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
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Ng ACH, Chahine M, Scantlebury MH, Appendino JP. Channelopathies in epilepsy: an overview of clinical presentations, pathogenic mechanisms, and therapeutic insights. J Neurol 2024; 271:3063-3094. [PMID: 38607431 DOI: 10.1007/s00415-024-12352-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
Pathogenic variants in genes encoding ion channels are causal for various pediatric and adult neurological conditions. In particular, several epilepsy syndromes have been identified to be caused by specific channelopathies. These encompass a spectrum from self-limited epilepsies to developmental and epileptic encephalopathies spanning genetic and acquired causes. Several of these channelopathies have exquisite responses to specific antiseizure medications (ASMs), while others ASMs may prove ineffective or even worsen seizures. Some channelopathies demonstrate phenotypic pleiotropy and can cause other neurological conditions outside of epilepsy. This review aims to provide a comprehensive exploration of the pathophysiology of seizure generation, ion channels implicated in epilepsy, and several genetic epilepsies due to ion channel dysfunction. We outline the clinical presentation, pathogenesis, and the current state of basic science and clinical research for these channelopathies. In addition, we briefly look at potential precision therapy approaches emerging for these disorders.
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Affiliation(s)
- Andy Cheuk-Him Ng
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada
- Division of Neurology, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta and Stollery Children's Hospital, Edmonton, AB, Canada
| | - Mohamed Chahine
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
- CERVO, Brain Research Centre, Quebec City, Canada
| | - Morris H Scantlebury
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada
- Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Calgary, Canada
| | - Juan P Appendino
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada.
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Shen W, Nwosu G, Honer M, Clasadonte J, Schmalzbauer S, Biven M, Langer K, Flamm C, Poliquin S, Mermer F, Dedeurwaerdere S, Hernandez MC, Kang JQ. γ-Aminobutyric acid transporter and GABA A receptor mechanisms in Slc6a1+/A288V and Slc6a1+/S295L mice associated with developmental and epileptic encephalopathies. Brain Commun 2024; 6:fcae110. [PMID: 38650830 PMCID: PMC11032196 DOI: 10.1093/braincomms/fcae110] [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: 07/08/2023] [Revised: 01/09/2024] [Accepted: 04/11/2024] [Indexed: 04/25/2024] Open
Abstract
We have previously characterized the molecular mechanisms for variants in γ-aminobutyric acid transporter 1-encoding solute carrier family 6-member 1 (SLC6A1) in vitro and concluded that a partial or complete loss of γ-aminobutyric acid uptake due to impaired protein trafficking is the primary aetiology. Impairment of γ-aminobutyric acid transporter 1 function could cause compensatory changes in the expression of γ-aminobutyric acid receptors, which, in turn, modify disease pathophysiology and phenotype. Here we used different approaches including radioactive 3H γ-aminobutyric acid uptake in cells and synaptosomes, immunohistochemistry and confocal microscopy as well as brain slice surface protein biotinylation to characterize Slc6a1+/A288V and Slc6a1+/S295L mice, representative of a partial or a complete loss of function of SLC6A1 mutations, respectively. We employed the γ-aminobutyric acid transporter 1-specific inhibitor [3H]tiagabine binding and GABAA receptor subunit-specific radioligand binding to profile the γ-aminobutyric acid transporter 1 and GABAA receptor expression in major brain regions such as cortex, cerebellum, hippocampus and thalamus. We also determined the total and surface expression of γ-aminobutyric acid transporter 1, γ-aminobutyric acid transporter 3 and expression of GABAA receptor in the major brain regions in the knockin mice. We found that γ-aminobutyric acid transporter 1 protein was markedly reduced in cortex, hippocampus, thalamus and cerebellum in both mutant mouse lines. Consistent with the findings of reduced γ-aminobutyric acid uptake for both γ-aminobutyric acid transporter 1(A288V) and γ-aminobutyric acid transporter 1(S295L), both the total and the γ-aminobutyric acid transporter 1-mediated 3H γ-aminobutyric acid reuptake was reduced. We found that γ-aminobutyric acid transporter 3 is only abundantly expressed in the thalamus and there was no compensatory increase of γ-aminobutyric acid transporter 3 in either of the mutant mouse lines. γ-Aminobutyric acid transporter 1 was reduced in both somatic regions and nonsomatic regions in both mouse models, in which a ring-like structure was identified only in the Slc6a1+/A288V mouse, suggesting more γ-aminobutyric acid transporter 1 retention inside endoplasmic reticulum in the Slc6a1+/A288V mouse. The [3H]tiagabine binding was similar in both mouse models despite the difference in γ-aminobutyric acid uptake function and γ-aminobutyric acid transporter 1 protein expression for both mutations. There were no differences in GABAA receptor subtype expression, except for a small increase in the expression of α5 subunits of GABAA receptor in the hippocampus of Slc6a1S295L homozygous mice, suggesting a potential interaction between the expression of this GABAA receptor subtype and the mutant γ-aminobutyric acid transporter 1. The study provides the first comprehensive characterization of the SLC6A1 mutations in vivo in two representative mouse models. Because both γ-aminobutyric acid transporter 1 and GABAA receptors are targets for anti-seizure medications, the findings from this study can help guide tailored treatment options based on the expression and function of γ-aminobutyric acid transporter 1 and GABAA receptor in SLC6A1 mutation-mediated neurodevelopmental and epileptic encephalopathies.
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Affiliation(s)
- Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Gerald Nwosu
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Brain Institute, Nashville, TN 37240, USA
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN 37232, USA
| | - Michael Honer
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Basel 4070, Switzerland
| | - Jerome Clasadonte
- Early Solutions, Neuroscience TA, UCB Biopharma SRL, Braine l’Alleud 1420, Belgium
| | - Svenja Schmalzbauer
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Basel 4070, Switzerland
| | - Marshall Biven
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Katherine Langer
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Carson Flamm
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sarah Poliquin
- Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Brain Institute, Nashville, TN 37240, USA
| | - Felicia Mermer
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | | | - Maria-Clemencia Hernandez
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Basel 4070, Switzerland
| | - Jing-Qiong Kang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Brain Institute, Nashville, TN 37240, USA
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Kennedy Center of Human Development, Nashville, TN 37232, USA
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Shen W, Flamm C, Delahanty AJ, Casteel E, Biven M, DeLeeuw MB, Poliquin S, Nwosu G, Randhave K, Kang JQ. 4-Phenylbutyrate promoted wild-type γ-aminobutyric acid type A receptor trafficking, reduced endoplasmic reticulum stress, and mitigated seizures in Gabrg2 +/Q390X mice associated with Dravet syndrome. Epilepsia 2024; 65:204-217. [PMID: 37746768 PMCID: PMC10842976 DOI: 10.1111/epi.17779] [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: 04/10/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 09/26/2023]
Abstract
OBJECTIVE γ-Aminobutyric acid type A (GABAA ) receptor subunit gene mutations are major causes of various epilepsy syndromes, including severe kinds such as Dravet syndrome. Although the GABAA receptor is a major target for antiseizure medications, treating GABAA receptor mutations with receptor channel modulators is ineffective. Here, we determined the effect of a novel treatment with 4-phenylbutyrate (PBA) in Gabrg2+/Q390X knockin mice associated with Dravet syndrome. METHODS We used biochemistry in conjunction with differential tagging of the wild-type and the mutant alleles, live brain slice surface biotinylation, microsome isolation, patch-clamp whole-cell recordings, and video-monitoring synchronized electroencephalographic (EEG) recordings in Gabrg2+/Q390X mice to determine the effect of PBA in vitro with recombinant GABAA receptors and in vivo with knockin mice. RESULTS We found that PBA reduced the mutant γ2(Q390X) subunit protein aggregates, enhanced the wild-type GABAA receptor subunits' trafficking, and increased the membrane expression of the wild-type receptors. PBA increased the current amplitude of GABA-evoked current in human embryonic kidney 293T cells and the neurons bearing the γ2(Q390X) subunit protein. PBA also proved to reduce endoplasmic reticulum (ER) stress caused by the mutant γ2(Q390X) subunit protein, as well as mitigating seizures and EEG abnormalities in the Gabrg2+/Q390X mice. SIGNIFICANCE This research has unveiled a promising and innovative approach for treating epilepsy linked to GABAA receptor mutations through an unconventional antiseizure mechanism. Rather than directly modulating the affected mutant channel, PBA facilitates the folding and transportation of wild-type receptor subunits to the cell membrane and synapse. Combining these findings with our previous study, which demonstrated PBA's efficacy in restoring GABA transporter 1 (encoded by SLC6A1) function, we propose that PBA holds significant potential for a wide range of genetic epilepsies. Its ability to target shared molecular pathways involving mutant protein ER retention and impaired protein membrane trafficking suggests broad application in treating such conditions.
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Affiliation(s)
- Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
| | - Carson Flamm
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
| | - Aiden J Delahanty
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
| | - Emmett Casteel
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
| | - Marshall Biven
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
| | - Melissa B DeLeeuw
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Sarah Poliquin
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
| | - Gerald Nwosu
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Karishma Randhave
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
| | - Jing-Qiong Kang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN
- the Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN
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Sourbron J, Proost R, Jansen K, Riva A, Eschermann K, Barnett JR, Lagae L. A novel GABRG2 variant in Sunflower syndrome: A case report and video EEG monitoring. Epileptic Disord 2023; 25:815-822. [PMID: 37632399 DOI: 10.1002/epd2.20154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/20/2023] [Accepted: 08/21/2023] [Indexed: 08/28/2023]
Abstract
OBJECTIVE Sunflower syndrome is a unique photosensitive epilepsy, characterized by heliotropism and stereotyped seizures associated with handwaving. These handwaving events (HWE) are thought to be an ictal phenomenon, although current data are contrasting. Photosensitive epilepsy occurs in 2%-5% of the epilepsy forms and several pathogenic gene variants have been associated with photosensitive epilepsy. However, the genetic etiology of Sunflower syndrome remains unknown. Antiseizure medications (ASM) efficacious in treating photosensitive epilepsy are valproic acid (VPA) and levetiracetam (LEV) although some forms, such as Sunflower syndrome, can be drug-resistant. METHODS AND RESULTS Here, we report an 8-year-old boy with an early onset of episodes of HWE that was initially categorized as behavioral problems for which risperidone was started. However, the medical history was suggestive of Sunflower syndrome, and subsequent video EEG showed focal mostly temporal and frontotemporal (right and left) epileptiform activity and confirmed the epileptic nature of the HWE. Thus, VPA was started and initially led to seizure frequency reduction. Molecular analyses showed a pathogenic variant in GABRG2 (c.1287G>A p.(Trp429Ter)), which has been associated with photosensitive and generalized epilepsy. SIGNIFICANCE Overall, clinicians worldwide should be cautious by interpreting HWE and/or other tic-like movements, since an epileptic origin cannot be ruled out. A prompt and correct diagnosis can be made by performing a video EEG early on in the diagnostic process when epileptic seizures are part of the differential diagnosis. Even though the genetic etiology of Sunflower syndrome remains poorly understood, this constellation supports further genetic testing since the detection of a pathogenic variant can help in making correct decisions regarding ASM management.
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Affiliation(s)
- Jo Sourbron
- Section Pediatric Neurology, Department of Development and Regeneration, University Hospital KU Leuven, Leuven, Belgium
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Renee Proost
- Section Pediatric Neurology, Department of Development and Regeneration, University Hospital KU Leuven, Leuven, Belgium
| | - Katrien Jansen
- Section Pediatric Neurology, Department of Development and Regeneration, University Hospital KU Leuven, Leuven, Belgium
| | - Antonella Riva
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genoa, Italy
- IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Kirsten Eschermann
- Research Institute for Rehabilitation, Transition and Palliation, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, University Hospital of the Paracelsus Medical University, Salzburg, Austria
- Clinic for Neuropediatrics and Neurological Rehabilitation, Epilepsy Center for Children and Adolescents, Schön Klinik Vogtareuth, Vogtareuth, Germany
| | - James Richard Barnett
- Pediatric Epilepsy, Program Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Lieven Lagae
- Section Pediatric Neurology, Department of Development and Regeneration, University Hospital KU Leuven, Leuven, Belgium
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Zhang Q, Forster-Gibson C, Bercovici E, Bernardo A, Ding F, Shen W, Langer K, Rex T, Kang JQ. Epilepsy plus blindness in microdeletion of GABRA1 and GABRG2 in mouse and human. Exp Neurol 2023; 369:114537. [PMID: 37703949 PMCID: PMC10591898 DOI: 10.1016/j.expneurol.2023.114537] [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: 03/26/2023] [Revised: 08/24/2023] [Accepted: 09/07/2023] [Indexed: 09/15/2023]
Abstract
OBJECTIVE GABAA receptor subunit gene (GABR) mutations are significant causes of epilepsy, including syndromic epilepsy. This report for the first time, describes intractable epilepsy and blindness due to optic atrophy in our patient, who has a microdeletion of the GABRA1 and GABRG2 genes. We then characterized the molecular phenotypes and determined patho-mechanisms underlying the genotype-phenotype correlations in a mouse model who is haploinsufficient for both genes (Gabra1+/-/Gabrg2+/- mouse). METHODS Electroencephalography was conducted in both human and mice with the same gene loss. GABAA receptor expression was evaluated by biochemical and imaging approaches. Optic nerve atrophy was evaluated with fundus photography in human while electronic microscopy, visual evoked potential and electroretinography recordings were conducted in mice. RESULTS The patient has bilateral optical nerve atrophy. Mice displayed spontaneous seizures, reduced electroretinography oscillatory potential and reduced GABAA receptor α1, β2 and γ2 subunit expression in various brain regions. Electronic microscopy showed that mice also had optic nerve degeneration, as indicated by increased G-ratio, the ratio of the inner axonal diameter to the total outer diameter, suggesting impaired myelination of axons. More importantly, we identified that phenobarbital was the most effective anticonvulsant in mice and the patient's seizures were also controlled with phenobarbital after failing multiple anti-seizure drugs. CONCLUSIONS This study is the first report of haploinsufficiency of two GABR epilepsy genes and visual impairment due to altered axonal myelination and resultant optic nerve atrophy. The study suggests the far-reaching impact of GABR mutations and the translational significance of animal models with the same etiology.
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Affiliation(s)
- Qi Zhang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America; Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Department of Neurology, Nantong University, 19 Qixiu Road, Nantong, JS 226001, PR China
| | - Cynthia Forster-Gibson
- Laboratory Medicine and Genetics, Trillium Health Partners, Mississauga and Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Canada
| | - Eduard Bercovici
- Division of Neurology, Faculty of Medicine, University of Toronto, Canada
| | - Alexandra Bernardo
- Department of Ophthalmology & Visual Sciences Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Fei Ding
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Department of Neurology, Nantong University, 19 Qixiu Road, Nantong, JS 226001, PR China
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Katherine Langer
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Tonia Rex
- Department of Ophthalmology & Visual Sciences Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America
| | - Jing-Qiong Kang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States of America; Department of Pharmacology, Vanderbilt University, United States of America; Vanderbilt Brain Institute and Vanderbilt Kennedy Center of Human Development, Vanderbilt University, Nashville, TN 37212, United States of America.
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Zhao S, Zhang X, Yang L, Wang Y, Jia S, Li X, Wang Z, Yang F, Liang M, Wang X, Wang D. ATP6V0C gene variants were identified in individuals with epilepsy, with or without developmental delay. J Hum Genet 2023; 68:589-597. [PMID: 37161035 DOI: 10.1038/s10038-023-01145-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 03/06/2023] [Accepted: 03/19/2023] [Indexed: 05/11/2023]
Abstract
The cause of epilepsy with or without developmental disorders was unidentified in a significant proportion of patients. Whole exome sequencing was performed in three unrelated patients with early-onset epilepsy, with or without developmental delay and intellectual disability. We identified de novo heterozygous variants (p.Arg119Trp, p.Val99_Ser102del, c.260_263 + 11delinsGCCCA) in the ATP6V0C gene, which encodes a subunit of vacuolar ATPase. Three-dimensional protein modeling showed that the variant p.Arg119Trp in ATP6V0C affected the hydrogen bonds with the 115th and 123rd residues, and the protein stability. The p.Val99_Ser102del and c.260_263 + 11delinsGCCCA variants in the other two patients resulted in a loss of function with microdeletion or splicing effects. Their seizures and psychomotor developmental outcomes were different, and all patients had a good prognosis. Our study provides evidence that de novo heterozygous ATP6V0C variants are related to epilepsy and associated with or without developmental delay.
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Affiliation(s)
- Siyu Zhao
- Department of Pediatric neurology, Xi'an Children's Hospital, Xi'an, China
| | - Xiaoling Zhang
- Department of neurology, The Mine Hospital of Xu Zhou, Xuzhou, China
| | - Le Yang
- Department of Pediatric neurology, Xi'an Children's Hospital, Xi'an, China
| | - Yan Wang
- Department of Pediatric neurology, Xi'an Children's Hospital, Xi'an, China
| | - ShanShan Jia
- Department of Pediatric neurology, Xi'an Children's Hospital, Xi'an, China
| | - Xia Li
- Department of Pediatric neurology, Xi'an Children's Hospital, Xi'an, China
| | - Zhijing Wang
- Department of Pediatric neurology, Xi'an Children's Hospital, Xi'an, China
| | | | | | - Xiuxia Wang
- Department of Pediatric, The Second Hospital of Heibei Medical University, Shijiazhuang, China.
| | - Dong Wang
- Department of Pediatric neurology, Xi'an Children's Hospital, Xi'an, China.
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10
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Aiba I, Ning Y, Noebels JL. A hyperthermic seizure unleashes a surge of spreading depolarizations in Scn1a-deficient mice. JCI Insight 2023; 8:e170399. [PMID: 37551713 PMCID: PMC10445687 DOI: 10.1172/jci.insight.170399] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/15/2023] [Indexed: 08/09/2023] Open
Abstract
Spreading depolarization (SD) is a massive wave of cellular depolarization that slowly migrates across the brain gray matter. Cortical SD is frequently generated following brain injury, while less is understood about its potential contribution to genetic disorders of hyperexcitability, such as SCN1A-deficient epilepsy, in which febrile seizure often contributes to disease initiation. Here we report that spontaneous SD waves are predominant EEG abnormalities in the Scn1a-deficient mouse (Scn1a+/R1407X) and undergo sustained intensification following a single hyperthermic seizure. Chronic DC-band EEG recording detected spontaneous SDs, seizures, and seizure-SD complexes in Scn1a+/R1407X mice but not WT littermates. The SD events were infrequent, while a single hyperthermia-induced seizure robustly increased SD frequency over 4-fold during the initial postictal week. This prolonged neurological aftermath could be suppressed by memantine administration. Video, electromyogram, and EEG spectral analysis revealed distinct neurobehavioral patterns; individual seizures were associated with increased motor activities, while SDs were generally associated with immobility. We also identified a stereotypic SD prodrome, detectable over a minute before the onset of the DC potential shift, characterized by increased motor activity and bilateral EEG frequency changes. Our study suggests that cortical SD is a pathological manifestation in SCN1A-deficient epileptic encephalopathy.
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11
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Frankel E, Podder A, Sharifi M, Pillai R, Belnap N, Ramsey K, Dodson J, Venugopal P, Brzezinski M, Llaci L, Gerald B, Mills G, Sanchez-Castillo M, Balak CD, Szelinger S, Jepsen WM, Siniard AL, Richholt R, Naymik M, Schrauwen I, Craig DW, Piras IS, Huentelman MJ, Schork NJ, Narayanan V, Rangasamy S. Genetic and Protein Network Underlying the Convergence of Rett-Syndrome-like (RTT-L) Phenotype in Neurodevelopmental Disorders. Cells 2023; 12:1437. [PMID: 37408271 DOI: 10.3390/cells12101437] [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: 02/07/2023] [Revised: 04/20/2023] [Accepted: 04/29/2023] [Indexed: 07/07/2023] Open
Abstract
Mutations of the X-linked gene encoding methyl-CpG-binding protein 2 (MECP2) cause classical forms of Rett syndrome (RTT) in girls. A subset of patients who are recognized to have an overlapping neurological phenotype with RTT but are lacking a mutation in a gene that causes classical or atypical RTT can be described as having a 'Rett-syndrome-like phenotype (RTT-L). Here, we report eight patients from our cohort diagnosed as having RTT-L who carry mutations in genes unrelated to RTT. We annotated the list of genes associated with RTT-L from our patient cohort, considered them in the light of peer-reviewed articles on the genetics of RTT-L, and constructed an integrated protein-protein interaction network (PPIN) consisting of 2871 interactions connecting 2192 neighboring proteins among RTT- and RTT-L-associated genes. Functional enrichment analysis of RTT and RTT-L genes identified a number of intuitive biological processes. We also identified transcription factors (TFs) whose binding sites are common across the set of RTT and RTT-L genes and appear as important regulatory motifs for them. Investigation of the most significant over-represented pathway analysis suggests that HDAC1 and CHD4 likely play a central role in the interactome between RTT and RTT-L genes.
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Affiliation(s)
- Eric Frankel
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Avijit Podder
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Megan Sharifi
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Roshan Pillai
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Newell Belnap
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Keri Ramsey
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Julius Dodson
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Pooja Venugopal
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Molly Brzezinski
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Lorida Llaci
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Brittany Gerald
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Gabrielle Mills
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Meredith Sanchez-Castillo
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Chris D Balak
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Szabolcs Szelinger
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Wayne M Jepsen
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Ashley L Siniard
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Ryan Richholt
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Marcus Naymik
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Department of Neurology, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY 10032, USA
| | - David W Craig
- Department of Translational Genomics, University of Southern California, Los Angeles, CA 90033, USA
| | - Ignazio S Piras
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Matthew J Huentelman
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Nicholas J Schork
- Quantitative Medicine Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Vinodh Narayanan
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
| | - Sampathkumar Rangasamy
- Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
- Center for Rare Childhood Disorders (C4RCD), Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA
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12
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Hernandez CC, Shen Y, Hu N, Shen W, Narayanan V, Ramsey K, He W, Zou L, Macdonald RL. GABRG2 Variants Associated with Febrile Seizures. Biomolecules 2023; 13:414. [PMID: 36979350 PMCID: PMC10046037 DOI: 10.3390/biom13030414] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 02/13/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Febrile seizures (FS) are the most common form of epilepsy in children between six months and five years of age. FS is a self-limited type of fever-related seizure. However, complicated prolonged FS can lead to complex partial epilepsy. We found that among the GABAA receptor subunit (GABR) genes, most variants associated with FS are harbored in the γ2 subunit (GABRG2). Here, we characterized the effects of eight variants in the GABAA receptor γ2 subunit on receptor biogenesis and channel function. Two-thirds of the GABRG2 variants followed the expected autosomal dominant inheritance in FS and occurred as missense and nonsense variants. The remaining one-third appeared as de novo in the affected probands and occurred only as missense variants. The loss of GABAA receptor function and dominant negative effect on GABAA receptor biogenesis likely caused the FS phenotype. In general, variants in the GABRG2 result in a broad spectrum of phenotypic severity, ranging from asymptomatic, FS, genetic epilepsy with febrile seizures plus (GEFS+), and Dravet syndrome individuals. The data presented here support the link between FS, epilepsy, and GABRG2 variants, shedding light on the relationship between the variant topological occurrence and disease severity.
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Affiliation(s)
- Ciria C. Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yanwen Shen
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Ningning Hu
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Vinodh Narayanan
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ 85004, USA
| | - Keri Ramsey
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ 85004, USA
| | - Wen He
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Liping Zou
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Robert L. Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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13
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Bryson A, Reid C, Petrou S. Fundamental Neurochemistry Review: GABA A receptor neurotransmission and epilepsy: Principles, disease mechanisms and pharmacotherapy. J Neurochem 2023; 165:6-28. [PMID: 36681890 DOI: 10.1111/jnc.15769] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/12/2022] [Accepted: 01/04/2023] [Indexed: 01/23/2023]
Abstract
Epilepsy is a common neurological disorder associated with alterations of excitation-inhibition balance within brain neuronal networks. GABAA receptor neurotransmission is the most prevalent form of inhibitory neurotransmission and is strongly implicated in both the pathophysiology and treatment of epilepsy, serving as a primary target for antiseizure medications for over a century. It is now established that GABA exerts a multifaceted influence through an array of GABAA receptor subtypes that extends far beyond simply negating excitatory activity. As the role of GABAA neurotransmission within inhibitory circuits is elaborated, this will enable the development of precision therapies that correct the network dysfunction underlying epileptic pathology.
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Affiliation(s)
- Alexander Bryson
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.,Department of Neurology, Austin Health, Heidelberg, Victoria, Australia
| | - Christopher Reid
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.,Praxis Precision Medicines, Inc., Cambridge, Massachusetts, USA
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14
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Zhang XL, Zhou JY, Zhang P, Lin L, Mei R, Zhang FL, Chen YM, Li R. Clptm1, a new target in suppressing epileptic seizure by regulating GABA A R-mediated inhibitory synaptic transmission in a PTZ-induced epilepsy model. Kaohsiung J Med Sci 2023; 39:61-69. [PMID: 36519412 DOI: 10.1002/kjm2.12629] [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: 05/19/2022] [Revised: 09/16/2022] [Accepted: 10/24/2022] [Indexed: 12/23/2022] Open
Abstract
Disruption of gamma-amino butyric acid type A receptors (GABAA Rs) synaptic clustering and a decrease in the number of GABAA Rs in the plasma membrane are thought to contribute to alteration of the balance between excitatory and inhibitory neurotransmission, which promotes seizure induction and propagation. The multipass transmembrane protein cleft lip and palate transmembrane protein 1 (Clptm1) controls the forward trafficking of GABAA R, thus decaying miniature inhibitory postsynaptic current (mIPSC) of inhibitory synapses. In this study, using a pentylenetetrazol (PTZ)-induced epilepsy rat model, we found that Clptm1 regulates epileptic seizures by modulating GABAA R-mediated inhibitory synaptic transmission. First, we showed that Clptm1 expression was elevated in the PTZ-induced epileptic rats. Subsequently, we found that downregulation of Clptm1 expression protected against PTZ-induced seizures, which was attributed to an increase in the number of GABAA Rγ2s in the plasma membrane and the amplitude of mIPSC. Taken together, our findings identify a new anti-seizure target that provides a theoretical basis for the development of novel strategies for the prevention and treatment of epilepsy.
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Affiliation(s)
- Xiao-Lin Zhang
- Department of Neurology, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Jin-Yu Zhou
- Department of Rehabilitation Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Peng Zhang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Lan Lin
- Department of Neurology, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Rong Mei
- Department of Neurology, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Feng-Li Zhang
- Department of Neurology, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Yang-Mei Chen
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Rong Li
- Department of Neurology, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, Yunnan, China
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15
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Catron MA, Howe RK, Besing GLK, St. John EK, Potesta CV, Gallagher MJ, Macdonald RL, Zhou C. Sleep slow-wave oscillations trigger seizures in a genetic epilepsy model of Dravet syndrome. Brain Commun 2022; 5:fcac332. [PMID: 36632186 PMCID: PMC9830548 DOI: 10.1093/braincomms/fcac332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/09/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Sleep is the preferential period when epileptic spike-wave discharges appear in human epileptic patients, including genetic epileptic seizures such as Dravet syndrome with multiple mutations including SCN1A mutation and GABAA receptor γ2 subunit Gabrg2Q390X mutation in patients, which presents more severe epileptic symptoms in female patients than male patients. However, the seizure onset mechanism during sleep still remains unknown. Our previous work has shown that the sleep-like state-dependent homeostatic synaptic potentiation can trigger epileptic spike-wave discharges in one transgenic heterozygous Gabrg2+/Q390X knock-in mouse model.1 Here, using this heterozygous knock-in mouse model, we hypothesized that slow-wave oscillations themselves in vivo could trigger epileptic seizures. We found that epileptic spike-wave discharges in heterozygous Gabrg2+/Q390X knock-in mice exhibited preferential incidence during non-rapid eye movement sleep period, accompanied by motor immobility/facial myoclonus/vibrissal twitching and more frequent spike-wave discharge incidence appeared in female heterozygous knock-in mice than male heterozygous knock-in mice. Optogenetically induced slow-wave oscillations in vivo significantly increased epileptic spike-wave discharge incidence in heterozygous Gabrg2+/Q390X knock-in mice with longer duration of non-rapid eye movement sleep or quiet-wakeful states. Furthermore, suppression of slow-wave oscillation-related homeostatic synaptic potentiation by 4-(diethylamino)-benzaldehyde injection (i.p.) greatly attenuated spike-wave discharge incidence in heterozygous knock-in mice, suggesting that slow-wave oscillations in vivo did trigger seizure activity in heterozygous knock-in mice. Meanwhile, sleep spindle generation in wild-type littermates and heterozygous Gabrg2+/Q390X knock-in mice involved the slow-wave oscillation-related homeostatic synaptic potentiation that also contributed to epileptic spike-wave discharge generation in heterozygous Gabrg2+/Q390X knock-in mice. In addition, EEG spectral power of delta frequency (0.1-4 Hz) during non-rapid eye movement sleep was significantly larger in female heterozygous Gabrg2+/Q390X knock-in mice than that in male heterozygous Gabrg2+/Q390X knock-in mice, which likely contributes to the gender difference in seizure incidence during non-rapid eye movement sleep/quiet-wake states of human patients. Overall, all these results indicate that slow-wave oscillations in vivo trigger the seizure onset in heterozygous Gabrg2+/Q390X knock-in mice, preferentially during non-rapid eye movement sleep period and likely generate the sex difference in seizure incidence between male and female heterozygous Gabrg2+/Q390X knock-in mice.
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Affiliation(s)
- Mackenzie A Catron
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rachel K Howe
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Gai-Linn K Besing
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Emily K St. John
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | | | - Martin J Gallagher
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Chengwen Zhou
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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16
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Williams A, Cooney E, Segal G, Narayanan S, Morand M, Agadi S. GABRG1 variant as a potential novel cause of epileptic encephalopathy, hypotonia, and global developmental delay. Am J Med Genet A 2022; 188:3546-3549. [PMID: 36121006 DOI: 10.1002/ajmg.a.62969] [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: 08/10/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 01/31/2023]
Abstract
Epileptic encephalopathies (EEs) are severe brain disorders with excessive ictal (seizure) and interictal (electrographic epileptiform discharges) activity in developing brain which may result in progressive cognitive and neuropsychological deterioration. In contrast to regular epilepsy where the treatment goal is to prevent the seizure (ictal) recurrence, in patients with EE the goal is to treat both ictal as well as interictal activity to prevent further progression. With the introduction of genetic sequencing technologies over the past 20 years, there is growing recognition of the genetic basis of EE, with the majority due to monogenic causes. Monogenic etiologies of EE include pathogenic variants in the γ-aminobutyric acid type A receptor (GABA-A) encoding gene family. We present a 2-year-old patient with EE, hypotonia, and global developmental delays. Clinical trio exome sequencing showed a novel, de novo variant in GABRG1. GABRG1 encodes the γ1 subunit of the GABA-A receptor. To date, there has not been an association of EE with pathogenic variants in GABRG1. This variant is predicted to be damaging to protein structure and function, and the patient's phenotype is similar to those with pathogenic variants in other members of the GABA-A receptor encoding gene family.
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Affiliation(s)
- Aaron Williams
- University of Texas Medical Branch School of Medicine, Galveston, Texas, USA
| | - Erin Cooney
- University of Texas Medical Branch School of Medicine, Galveston, Texas, USA.,Division of Medical Genetics and Metabolism, Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Gabrielle Segal
- University of Texas Medical Branch School of Medicine, Galveston, Texas, USA
| | - Swetha Narayanan
- University of Texas Medical Branch School of Medicine, Galveston, Texas, USA.,Division of Medical Genetics and Metabolism, Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Megan Morand
- University of Texas Medical Branch School of Medicine, Galveston, Texas, USA.,Division of Medical Genetics and Metabolism, Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Satish Agadi
- University of Texas Medical Branch School of Medicine, Galveston, Texas, USA.,Division of Neurology, Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
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17
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Tissue-wide cell-specific proteogenomic modeling reveals novel candidate risk genes in autism spectrum disorders. NPJ Syst Biol Appl 2022; 8:31. [PMID: 36068227 PMCID: PMC9448731 DOI: 10.1038/s41540-022-00243-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 08/05/2022] [Indexed: 11/08/2022] Open
Abstract
Autism spectrum disorders (ASD) are a set of complex neurodevelopmental diseases characterized with repetitive behavioral patterns and communication disabilities. Using a systems biology method called MAPSD (Markov Affinity-based Proteogenomic Signal Diffusion) for joint modeling of proteome dynamics and a wide array of omics datasets, we identified a list of candidate ASD risk genes. Leveraging the collected biological signals as well as a large-scale protein-protein interaction network adjusted based on single cell resolution proteome properties in four brain regions, we observed an agreement between the known and the newly identified candidate genes that are spatially enriched in neuronal cells within cerebral cortex at the protein level. Moreover, we created a detailed subcellular localization enrichment map of the known and the identified genes across 32 micro-domains and showed that neuronal cells and neuropils share the largest fraction of signal enrichment in cerebral cortex. Notably, we showed that the identified genes are among the transcriptional biomarkers of inhibitory and excitatory neurons in human frontal cortex. Intersecting the identified genes with a single cell RNA-seq data on ASD brains further evidenced that 20 candidate genes, including GRIK1, EMX2, STXBP6, and KCNJ3 are disrupted in distinct cell-types. Moreover, we showed that ASD risk genes are predominantly distributed in certain human interactome modules, and that the identified genes may act as the regulator for some of the known ASD loci. In summary, our study demonstrated how tissue-wide cell-specific proteogenomic modeling can reveal candidate genes for brain disorders that can be supported by convergent lines of evidence.
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18
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Leung HW, Foo G, VanDongen A. Arc Regulates Transcription of Genes for Plasticity, Excitability and Alzheimer’s Disease. Biomedicines 2022; 10:biomedicines10081946. [PMID: 36009494 PMCID: PMC9405677 DOI: 10.3390/biomedicines10081946] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 02/06/2023] Open
Abstract
The immediate early gene Arc is a master regulator of synaptic function and a critical determinant of memory consolidation. Here, we show that Arc interacts with dynamic chromatin and closely associates with histone markers for active enhancers and transcription in cultured rat hippocampal neurons. Both these histone modifications, H3K27Ac and H3K9Ac, have recently been shown to be upregulated in late-onset Alzheimer’s disease (AD). When Arc induction by pharmacological network activation was prevented using a short hairpin RNA, the expression profile was altered for over 1900 genes, which included genes associated with synaptic function, neuronal plasticity, intrinsic excitability, and signalling pathways. Interestingly, about 100 Arc-dependent genes are associated with the pathophysiology of AD. When endogenous Arc expression was induced in HEK293T cells, the transcription of many neuronal genes was increased, suggesting that Arc can control expression in the absence of activated signalling pathways. Taken together, these data establish Arc as a master regulator of neuronal activity-dependent gene expression and suggest that it plays a significant role in the pathophysiology of AD.
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Affiliation(s)
| | - Gabriel Foo
- Duke-NUS Medical School, Singapore 169857, Singapore
| | - Antonius VanDongen
- Duke-NUS Medical School, Singapore 169857, Singapore
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
- Correspondence:
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19
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Ochenkowska K, Herold A, Samarut É. Zebrafish Is a Powerful Tool for Precision Medicine Approaches to Neurological Disorders. Front Mol Neurosci 2022; 15:944693. [PMID: 35875659 PMCID: PMC9298522 DOI: 10.3389/fnmol.2022.944693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 06/17/2022] [Indexed: 12/17/2022] Open
Abstract
Personalized medicine is currently one of the most promising tools which give hope to patients with no suitable or no available treatment. Patient-specific approaches are particularly needed for common diseases with a broad phenotypic spectrum as well as for rare and yet-undiagnosed disorders. In both cases, there is a need to understand the underlying mechanisms and how to counteract them. Even though, during recent years, we have been observing the blossom of novel therapeutic techniques, there is still a gap to fill between bench and bedside in a patient-specific fashion. In particular, the complexity of genotype-to-phenotype correlations in the context of neurological disorders has dampened the development of successful disease-modifying therapeutics. Animal modeling of human diseases is instrumental in the development of therapies. Currently, zebrafish has emerged as a powerful and convenient model organism for modeling and investigating various neurological disorders. This model has been broadly described as a valuable tool for understanding developmental processes and disease mechanisms, behavioral studies, toxicity, and drug screening. The translatability of findings obtained from zebrafish studies and the broad prospect of human disease modeling paves the way for developing tailored therapeutic strategies. In this review, we will discuss the predictive power of zebrafish in the discovery of novel, precise therapeutic approaches in neurosciences. We will shed light on the advantages and abilities of this in vivo model to develop tailored medicinal strategies. We will also investigate the newest accomplishments and current challenges in the field and future perspectives.
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Affiliation(s)
- Katarzyna Ochenkowska
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada.,Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
| | - Aveeva Herold
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada.,Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
| | - Éric Samarut
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada.,Department of Neuroscience, Université de Montréal, Montreal, QC, Canada.,Modelis Inc., Montreal, QC, Canada
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20
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Zhang L, Liu X. Clinical phenotype and genotype of children with GABAA receptor α1 subunit gene-related epilepsy. Front Neurol 2022; 13:941054. [PMID: 35937053 PMCID: PMC9350551 DOI: 10.3389/fneur.2022.941054] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/27/2022] [Indexed: 12/03/2022] Open
Abstract
Objective This study aimed to summarize the clinical phenotype and genotype of children with epilepsy caused by GABRA1 gene variants. Methods Eight epilepsy patients, who were admitted to Qilu Hospital of Shandong University from 2015 to 2021, were enrolled in the study. GABRA1 gene variants were detected by whole-exome sequencing. Epilepsy clinical manifestations, electroencephalography, neuroimaging characteristics and treatment methods were retrospectively analyzed. Results Among the eight patients, four were males and four were females. Epilepsy onset age was between 3 and 8 months of age. Two patients had a family history of epilepsy. Six cases were de novo variants, and two were hereditary variants. Two children carried the same pathogenic variants, and five carried novel pathogenic variants that had not been reported internationally. The types of seizures were diverse, including focal seizures in five cases, generalized tonic-clonic seizures in five cases, and spasms in two cases. Electroencephalography of seven cases showed abnormal background rhythms, and six cases showed abnormal discharge during the interictal period. No obvious abnormalities were found on magnetic resonance imaging in five cases. All eight children had different degrees of developmental retardation. Conclusion De novo pathogenic variants in GABRA1 are more common than inherited pathogenic variants, and most epilepsy symptoms begin in the first year of life, manifesting with a variety of seizure types and developmental delays. Conventional treatment usually involves one or more drugs; although drug treatment can control seizures in some cases, cognitive and developmental deficits often exist. The five newly discovered pathogenic variants enrich the GABRA1 gene pathogenic variant spectrum.
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21
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Phenotypic and Genotypic Spectrum of Early-Onset Developmental and Epileptic Encephalopathies-Data from a Romanian Cohort. Genes (Basel) 2022; 13:genes13071253. [PMID: 35886038 PMCID: PMC9322987 DOI: 10.3390/genes13071253] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 02/01/2023] Open
Abstract
Early-onset developmental epileptic encephalopathy (DEE) refers to an age-specific, diverse group of epilepsy syndromes with electroclinical anomalies that are associated with severe cognitive, behavioral, and developmental impairments. Genetic DEEs have heterogeneous etiologies. This study includes 36 Romanian patients referred to the Regional Centre for Medical Genetics Dolj for genetic testing between 2017 and 2020. The patients had been admitted to and clinically evaluated at Doctor Victor Gomoiu Children’s Hospital and Prof. Dr. Alexandru Obregia Psychiatry Hospital in Bucharest. Panel testing was performed using the Illumina® TruSight™ One “clinical exome” (4811 genes), and the analysis focused on the known genes reported in DEEs and clinical concordance. The overall diagnostic rate was 25% (9/36 cases). Seven cases were diagnosed with Dravet syndrome (likely pathogenic/pathogenic variants in SCN1A) and two with Genetic Epilepsy with Febrile Seizures Plus (SCN1B). For the diagnosed patients, seizure onset was <1 year, and the seizure type was generalized tonic-clonic. Four additional plausible variants of unknown significance in SCN2A, SCN9A, and SLC2A1 correlated with the reported phenotype. Overall, we are reporting seven novel variants. Comprehensive clinical phenotyping is crucial for variant interpretation. Genetic assessment of patients with severe early-onset DEE can be a powerful diagnostic tool for clinicians, with implications for the management and counseling of the patients and their families.
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22
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Feng Y, Wei ZH, Liu C, Li GY, Qiao XZ, Gan YJ, Zhang CC, Deng YC. Genetic variations in GABA metabolism and epilepsy. Seizure 2022; 101:22-29. [PMID: 35850019 DOI: 10.1016/j.seizure.2022.07.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 07/10/2022] [Accepted: 07/11/2022] [Indexed: 11/18/2022] Open
Abstract
Epilepsy is a paroxysmal brain disorder that results from an imbalance between neuronal excitation and inhibition. Gamma-aminobutyric acid (GABA) is the most important inhibitory neurotransmitter in the brain and plays an important role in the occurrence and development of epilepsy. Abnormalities in all aspects of GABA metabolism, including GABA synthesis, transport, genes encoding GABA receptors, and GABA inactivation, may lead to epilepsy. GABRA1, GABRA2, GABRA5, GABRB1, GABRB2, GABRB3, GABRG2 and GABBR2 are genes that encode GABA receptors and are commonly associated with epilepsy. Mutations of these genes lead to a variety of epilepsy syndromes with different clinical phenotypes, primarily by down regulating receptor expression and reducing the amplitude of GABA-evoked potentials. GABA is metabolized by GABA transaminase and succinate semi aldehyde dehydrogenase, which are encoded by the ABAT and ALDH5A1 genes, respectively. Mutations of these genes result in symptoms related to deficiency of GABA transaminase and succinate semi aldehyde dehydrogenase, such as epilepsy and cognitive impairment. Most of the variation in genes associated with GABA metabolism are accompanied by developmental disorders. This review focuses on advances in understanding the relationship between genetic variation in GABA metabolism and epilepsy to establish a basis for the accurate diagnosis and treatment of epilepsy.
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Affiliation(s)
- Yan Feng
- Xi'an Medical University, Xi'an 710021, People's Republic of China; Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Zi-Han Wei
- Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Chao Liu
- Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Guo-Yan Li
- Xi'an Medical University, Xi'an 710021, People's Republic of China; Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Xiao-Zhi Qiao
- Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Ya-Jing Gan
- Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Chu-Chu Zhang
- Xi'an Medical University, Xi'an 710021, People's Republic of China
| | - Yan-Chun Deng
- Department of Neurology, Epilepsy Center of Xijing Hospital, Fourth Military Medical University, Xi'an 710032, People's Republic of China.
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23
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Genetics and gene therapy in Dravet syndrome. Epilepsy Behav 2022; 131:108043. [PMID: 34053869 DOI: 10.1016/j.yebeh.2021.108043] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 05/02/2021] [Accepted: 05/02/2021] [Indexed: 12/17/2022]
Abstract
Dravet syndrome is a well-established electro-clinical condition first described in 1978. A main genetic cause was identified with the discovery of a loss-of-function SCN1A variant in 2001. Mechanisms underlying the phenotypic variations have subsequently been a main topic of research. Various genetic modifiers of clinical severities have been elucidated through many rigorous studies on genotype-phenotype correlations and the recent advances in next generation sequencing technology. Furthermore, a deeper understanding of the regulation of gene expression and remarkable progress on genome-editing technology using the CRISPR-Cas9 system provide significant opportunities to overcome hurdles of gene therapy, such as enhancing NaV1.1 expression. This article reviews the current understanding of genetic pathology and the status of research toward the development of gene therapy for Dravet syndrome. This article is part of the Special Issue "Severe Infantile Epilepsies".
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24
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Yadav R, Shah S, Bhandari B, Marasini K, Mandal P, Murarka H, Pandey AK, Sharma Paudel B. Patient with Dravet syndrome: A case report. Clin Case Rep 2022; 10:e05840. [PMID: 35540719 PMCID: PMC9069364 DOI: 10.1002/ccr3.5840] [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: 08/29/2021] [Revised: 03/17/2022] [Accepted: 04/22/2022] [Indexed: 12/02/2022] Open
Abstract
Dravet syndrome is rare genetic epilepsy syndrome and epileptic encephalopathy. The patient initially has normal developmental profile with plateau or regression that begins after seizure onset. We report a case of two-year-old child diagnosed as dravet syndrome with moderate cerebral atrophy and ventricular dilatation as rare MRI finding.
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Affiliation(s)
- Rukesh Yadav
- Maharajgunj Medical CampusInstitute of MedicineTribhuvan UniversityMaharajgunjNepal
| | - Sangam Shah
- Maharajgunj Medical CampusInstitute of MedicineTribhuvan UniversityMaharajgunjNepal
| | - Bibek Bhandari
- Department of Internal MedicineMaharajgunj Medical CampusInstitute of MedicineTribhuvan UniversityMaharajgunjNepal
| | - Kundan Marasini
- Department of RadiologyMaharajgunj Medical CampusInstitute of MedicineTribhuvan UniversityMaharajgunjNepal
| | - Prince Mandal
- Maharajgunj Medical CampusInstitute of MedicineTribhuvan UniversityMaharajgunjNepal
| | - Hritik Murarka
- Maharajgunj Medical CampusInstitute of MedicineTribhuvan UniversityMaharajgunjNepal
| | - Anuj Kumar Pandey
- Maharajgunj Medical CampusInstitute of MedicineTribhuvan UniversityMaharajgunjNepal
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25
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Jiang YL, Song CG, Zhou HM, Feng B, Zhao JJ, Liu Y, Man YL, Han J, Liu SB, Jiang W. Rare variants in GABRG2 associated with sleep-related hypermotor epilepsy. J Neurol 2022; 269:4939-4954. [PMID: 35486215 DOI: 10.1007/s00415-022-11137-4] [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: 02/12/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 10/18/2022]
Abstract
Sleep-related hypermotor epilepsy (SHE) is a focal epilepsy syndrome. The underlying pathophysiology is presumed to be closely related with disruption of GABAergic neurotransmission, which is mainly medicated by γ-aminobutyric acid type A receptor (GABAAR). Thus, it is reasonable to assume that rare GABAAR variants might contribute to the pathogenesis of SHE. To test this hypothesis, we performed next-generation sequencing in 58 SHE patients and analyzed the functional effects of the identified variants in both neuronal and non-neuronal cells using a combination of electrophysiology recordings, western blot, flow cytometry, and confocal microscopy. In our study, we detected three rare variants (NM_198904.2: c.269C > T, p.T90M; NM_198904.2: c.950C > A, p.T317N and NM_198903.2: c.649C > T, p.Q217X) in GABRG2 (MIM:137,164, encoding GABAAR γ2 subunit) in three unrelated patients. Two of the three rare variants were transmitted unaffected maternally (T90M) or unaffected paternally (Q217X), whereas the T317N variant arose de novo. The mother of proband carrying the T90M variant was unaffected and being mosaicism for this variant. Functional analysis showed that T90M and T317N variants decreased GABA-evoked current amplitudes by diverse mechanisms including impaired surface expression, endoplasmic reticulum retention, and channel gating defects. And Q217X variant reduced synaptic clustering and distribution of GABAAR. While a causal role of these variants cannot be established directly from these results, the functional assessment together with the genetic sequencing suggests that these rare GABRG2 variants may constitute genetic risk factors for SHE. Our study further expands the GABRG2 phenotypic spectrum and supports the view that GABAergic neurotransmission participates in the epileptogenesis of SHE.
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Affiliation(s)
- Yong-Li Jiang
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Chang-Geng Song
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Hui-Min Zhou
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Ban Feng
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Jing-Jing Zhao
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Yu Liu
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Yu-Lin Man
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Jing Han
- MOE Key Laboratory of Modern Teaching Technology, Center for Teacher Professional Ability Development, Shaanxi Normal University, 199 South Chang'an Road, Xi'an, China.
| | - Shui-Bing Liu
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China.
| | - Wen Jiang
- Comprehensive Epilepsy Center, Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China.
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26
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Degener MJF, van Cruchten RTP, Otero BA, Wang E, Wansink DG, ‘t Hoen PAC. A comprehensive atlas of fetal splicing patterns in the brain of adult myotonic dystrophy type 1 patients. NAR Genom Bioinform 2022; 4:lqac016. [PMID: 35274098 PMCID: PMC8903011 DOI: 10.1093/nargab/lqac016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 01/28/2022] [Accepted: 02/13/2022] [Indexed: 11/14/2022] Open
Abstract
In patients with myotonic dystrophy type 1 (DM1), dysregulation of RNA-binding proteins like MBNL and CELF1 leads to alternative splicing of exons and is thought to induce a return to fetal splicing patterns in adult tissues, including the central nervous system (CNS). To comprehensively evaluate this, we created an atlas of developmentally regulated splicing patterns in the frontal cortex of healthy individuals and DM1 patients, by combining RNA-seq data from BrainSpan, GTEx and DM1 patients. Thirty-four splice events displayed an inclusion pattern in DM1 patients that is typical for the fetal situation in healthy individuals. The regulation of DM1-relevant splicing patterns could partly be explained by changes in mRNA expression of the splice regulators MBNL1, MBNL2 and CELF1. On the contrary, interindividual differences in splicing patterns between healthy adults could not be explained by differential expression of these splice regulators. Our findings lend transcriptome-wide evidence to the previously noted shift to fetal splicing patterns in the adult DM1 brain as a consequence of an imbalance in antagonistic MBNL and CELF1 activities. Our atlas serves as a solid foundation for further study and understanding of the cognitive phenotype in patients.
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Affiliation(s)
- Max J F Degener
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Remco T P van Cruchten
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Brittney A Otero
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, FL 32610-0266 Gainesville, FL, USA
| | - Eric T Wang
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, FL 32610-0266 Gainesville, FL, USA
| | - Derick G Wansink
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Peter A C ‘t Hoen
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
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27
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Skotte L, Fadista J, Bybjerg-Grauholm J, Appadurai V, Hildebrand MS, Hansen TF, Banasik K, Grove J, Albiñana C, Geller F, Bjurström CF, Vilhjálmsson BJ, Coleman M, Damiano JA, Burgess R, Scheffer IE, Pedersen OBV, Erikstrup C, Westergaard D, Nielsen KR, Sørensen E, Bruun MT, Liu X, Hjalgrim H, Pers TH, Mortensen PB, Mors O, Nordentoft M, Dreier JW, Børglum AD, Christensen J, Hougaard DM, Buil A, Hviid A, Melbye M, Ullum H, Berkovic SF, Werge T, Feenstra B. Genome-wide association study of febrile seizures implicates fever response and neuronal excitability genes. Brain 2022; 145:555-568. [PMID: 35022648 PMCID: PMC9128543 DOI: 10.1093/brain/awab260] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/09/2021] [Accepted: 06/07/2021] [Indexed: 12/19/2022] Open
Abstract
Febrile seizures represent the most common type of pathological brain activity in
young children and are influenced by genetic, environmental and developmental
factors. In a minority of cases, febrile seizures precede later development of
epilepsy. We conducted a genome-wide association study of febrile seizures in 7635 cases
and 83 966 controls identifying and replicating seven new loci, all with
P < 5 × 10−10. Variants at two loci were functionally related to altered expression of the fever
response genes PTGER3 and IL10, and four other
loci harboured genes (BSN, ERC2,
GABRG2, HERC1) influencing neuronal
excitability by regulating neurotransmitter release and binding, vesicular
transport or membrane trafficking at the synapse. Four previously reported loci
(SCN1A, SCN2A, ANO3 and
12q21.33) were all confirmed. Collectively, the seven novel and four previously
reported loci explained 2.8% of the variance in liability to febrile
seizures, and the single nucleotide polymorphism heritability based on all
common autosomal single nucleotide polymorphisms was 10.8%.
GABRG2, SCN1A and SCN2A
are well-established epilepsy genes and, overall, we found positive genetic
correlations with epilepsies (rg = 0.39,
P = 1.68 × 10−4). Further,
we found that higher polygenic risk scores for febrile seizures were associated
with epilepsy and with history of hospital admission for febrile seizures.
Finally, we found that polygenic risk of febrile seizures was lower in febrile
seizure patients with neuropsychiatric disease compared to febrile seizure
patients in a general population sample. In conclusion, this largest genetic investigation of febrile seizures to date
implicates central fever response genes as well as genes affecting neuronal
excitability, including several known epilepsy genes. Further functional and
genetic studies based on these findings will provide important insights into the
complex pathophysiological processes of seizures with and without fever.
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Affiliation(s)
- Line Skotte
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
| | - João Fadista
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
- Department of Clinical Sciences, Lund University Diabetes Centre, Malmö, Sweden
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Jonas Bybjerg-Grauholm
- Danish Centre for Neonatal Screening, Department of Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
| | - Vivek Appadurai
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
- Mental Health Center Sct. Hans, Mental Health Services, Capital Region Denmark, Roskilde, Denmark
| | - Michael S Hildebrand
- Epilepsy Research Centre, Department of Medicine, University of Melbourne (Austin Health), Victoria, Australia
- Murdoch Children’s Research Institute, Parkville, Victoria, Australia
| | - Thomas F Hansen
- Danish Headache Center, Department of Neurology, Rigshospitalet-Glostrup, Denmark
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Karina Banasik
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Jakob Grove
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
- Centre for Integrative Sequencing, iSEQ, Aarhus University, Aarhus, Denmark
- Department of Biomedicine–Human Genetics, Aarhus University, Aarhus, Denmark
- Bioinformatics Research Centre, Aarhus University, Aarhus, Denmark
| | - Clara Albiñana
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
- National Centre for Register-Based Research, Aarhus University, Aarhus, Denmark
| | - Frank Geller
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
| | - Carmen F Bjurström
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
| | - Bjarni J Vilhjálmsson
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
- National Centre for Register-Based Research, Aarhus University, Aarhus, Denmark
| | - Matthew Coleman
- Epilepsy Research Centre, Department of Medicine, University of Melbourne (Austin Health), Victoria, Australia
- Murdoch Children’s Research Institute, Parkville, Victoria, Australia
| | - John A Damiano
- Epilepsy Research Centre, Department of Medicine, University of Melbourne (Austin Health), Victoria, Australia
| | - Rosemary Burgess
- Epilepsy Research Centre, Department of Medicine, University of Melbourne (Austin Health), Victoria, Australia
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, University of Melbourne (Austin Health), Victoria, Australia
- Department of Paediatrics, Royal Children's Hospital, The University of Melbourne, Flemington, Victoria, Australia
- The Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria, Australia
| | | | - Christian Erikstrup
- Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark
| | - David Westergaard
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Kaspar René Nielsen
- Department of Clinical Immunology, Aalborg University Hospital North, Aalborg, Denmark
| | - Erik Sørensen
- Department of Clinical Immunology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Mie Topholm Bruun
- Department of Clinical Immunology, Odense University Hospital, Odense, Denmark
| | - Xueping Liu
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
| | - Henrik Hjalgrim
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
- Department of Haematology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tune H Pers
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Preben Bo Mortensen
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
- Centre for Integrative Sequencing, iSEQ, Aarhus University, Aarhus, Denmark
- National Centre for Register-Based Research, Aarhus University, Aarhus, Denmark
| | - Ole Mors
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark
| | - Merete Nordentoft
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Mental Health Center Copenhagen, Mental Health Services in the Capital Region of Denmark, Copenhagen, Denmark
| | - Julie W Dreier
- National Centre for Register-Based Research, Aarhus University, Aarhus, Denmark
| | - Anders D Børglum
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
- Centre for Integrative Sequencing, iSEQ, Aarhus University, Aarhus, Denmark
- Department of Biomedicine–Human Genetics, Aarhus University, Aarhus, Denmark
| | - Jakob Christensen
- National Centre for Register-Based Research, Aarhus University, Aarhus, Denmark
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - David M Hougaard
- Danish Centre for Neonatal Screening, Department of Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
| | - Alfonso Buil
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
- Mental Health Center Sct. Hans, Mental Health Services, Capital Region Denmark, Roskilde, Denmark
| | - Anders Hviid
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
- Department of Drug Design and Pharmacology, Pharmacovigilance Research Center, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mads Melbye
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Henrik Ullum
- Department of Clinical Immunology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Statens Serum Institut, Copenhagen, Denmark
| | - Samuel F Berkovic
- Epilepsy Research Centre, Department of Medicine, University of Melbourne (Austin Health), Victoria, Australia
| | - Thomas Werge
- iPSYCH, The Lundbeck Foundation Initiative for Integrative Psychiatric Research, Aarhus, Denmark
- Mental Health Center Sct. Hans, Mental Health Services, Capital Region Denmark, Roskilde, Denmark
| | - Bjarke Feenstra
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
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OUP accepted manuscript. Brain 2022; 145:416-417. [DOI: 10.1093/brain/awac036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
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Yang Y, Niu X, Cheng M, Zeng Q, Deng J, Tian X, Wang Y, Yu J, Shi W, Wu W, Ma J, Li Y, Yang X, Zhang X, Jia T, Yang Z, Liao J, Sun Y, Zheng H, Sun S, Sun D, Jiang Y, Zhang Y. Phenotypic Spectrum and Prognosis of Epilepsy Patients With GABRG2 Variants. Front Mol Neurosci 2022; 15:809163. [PMID: 35359574 PMCID: PMC8964129 DOI: 10.3389/fnmol.2022.809163] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 01/28/2022] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE This study aimed to obtain a comprehensive understanding of the genetic and phenotypic aspects of GABRG2-related epilepsy and its prognosis and to explore the potential prospects for personalized medicine. METHODS Through a multicenter collaboration in China, we analyzed the genotype-phenotype correlation and antiseizure medication (ASM) of patients with GABRG2-related epilepsy. The three-dimensional protein structure of the GABRG2 variant was modeled to predict the effect of GABRG2 missense variants using PyMOL 2.3 software. RESULTS In 35 patients with GABRG2 variants, 22 variants were de novo, and 18 variants were novel. The seizure onset age was ranged from 2 days after birth to 34 months (median age: 9 months). The seizure onset age was less than 1 year old in 22 patients (22/35, 62.9%). Seizure types included focal seizures (68.6%), generalized tonic-clonic seizures (60%), myoclonic seizures (14.3%), and absence seizures (11.4%). Other clinical features included fever-sensitive seizures (91.4%), cluster seizures (57.1%), and developmental delay (45.7%). Neuroimaging was abnormal in 2 patients, including dysplasia of the frontotemporal cortex and delayed myelination of white matter. Twelve patients were diagnosed with febrile seizures plus, eleven with epilepsy and developmental delay, two with Dravet syndrome, two with developmental and epileptic encephalopathy, two with focal epilepsy, two with febrile seizures, and four with unclassified epilepsy. The proportions of patients with missense variants in the extracellular region and the transmembrane region exhibiting developmental delay were 40% and 63.2%, respectively. The last follow-up age ranged from 11 months to 17 years. Seizures were controlled in 71.4% of patients, and 92% of their seizures were controlled by valproate and/or levetiracetam. CONCLUSION The clinical features of GABRG2-related epilepsy included seizure onset, usually in infancy, and seizures were fever-sensitive. More than half of the patients had cluster seizures. Phenotypes of GABRG2-related epilepsy were ranged from mild febrile seizures to severe epileptic encephalopathies. Most patients with GABRG2 variants who experienced seizures had a good prognosis. Valproate and levetiracetam were effective treatments for most patients.
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Affiliation(s)
- Ying Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xueyang Niu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Miaomiao Cheng
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Qi Zeng
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Jie Deng
- Department of Neurology, Beijing Children’s Hospital, Capital Medical University, Beijing, China
| | - Xiaojuan Tian
- Department of Neurology, Beijing Children’s Hospital, Capital Medical University, Beijing, China
| | - Yi Wang
- Department of Neurology, National Children’s Medical Center, Children’s Hospital of Fudan University, Shanghai, China
| | - Jing Yu
- Department of Neurology, Children’s Hospital of Xinjiang Uygur Autonomous Region, Xinjiang Hospital of Beijing Children’s Hospital, Ürümqi, China
| | - Wenli Shi
- Department of Pediatrics, The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, China
| | - Wenjuan Wu
- Department of Neurology, Hebei Children’s Hospital, Shijiazhuang, China
| | - Jiehui Ma
- Department of Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yufen Li
- Department of Pediatrics, Linyi People’s Hospital, Linyi, China
| | - Xiaoling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xiaoli Zhang
- Department of Pediatrics, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Tianming Jia
- Department of Pediatrics, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zhixian Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jianxiang Liao
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Yan Sun
- Department of Neurology, Children’s Hospital of Xinjiang Uygur Autonomous Region, Xinjiang Hospital of Beijing Children’s Hospital, Ürümqi, China
| | - Hong Zheng
- Department of Pediatrics, The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, China
| | - Suzhen Sun
- Department of Neurology, Hebei Children’s Hospital, Shijiazhuang, China
| | - Dan Sun
- Department of Neurology, Wuhan Children’s Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- *Correspondence: Yuehua Zhang,
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Zhou J, Liang W, Wang J, Chen J, Liu D, Wang X, Wu Y, Zhang Q, Shen D. An epileptic encephalopathy associated GABRG2 missense mutation leads to pre- and postsynaptic defects in zebrafish. Hum Mol Genet 2021; 31:3216-3230. [PMID: 34957497 DOI: 10.1093/hmg/ddab338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 11/09/2021] [Accepted: 11/15/2021] [Indexed: 11/13/2022] Open
Abstract
Mutations in the γ-aminobutyric acid type A (GABAA) receptor γ2 subunit gene, GABRG2, have been associated with a variety of epilepsy syndromes. A de novo mutation (c.T1027C, p.F343L) in GABRG2 was identified in a patient with early onset epileptic encephalopathy. Zebrafish overexpressing mutant human GABRG2 (F343L) subunits displayed spontaneous seizure activity and convulsive behaviors. In this study, we demonstrated that Tg (hGABRG2F343L) zebrafish displayed hyperactivity during light phase with normal circadian rhythm, as well as increased drug-induced locomotor activity. Real-time quantitative PCR, whole mount in situ hybridization and western blotting showed that Tg(hGABRG2F343L) zebrafish had altered expression of GABAA receptor subunits. Furthermore, investigation of synaptic protein expression and synapse ultrastructure uncovered a robust synaptic phenotype that is causally linked to GABRG2(F343L) mutation. Strikingly, Tg(hGABRG2F343L) zebrafish not only had postsynaptic defects, but also displayed an unanticipated deficit at the presynaptic level. Overall, our Tg(hGABRG2F343L) overexpression zebrafish model has expanded the GABAergic paradigm in epileptic encephalopathy from channelopathy to synaptopathy.
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Affiliation(s)
- Jing Zhou
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Wenpeng Liang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Jie Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Juan Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Dong Liu
- School of Life Science, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Xin Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Youjia Wu
- Department of Pediatrics, Affiliated Hospital of Nantong University, Nantong, China
| | - Qi Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Dingding Shen
- Department of Neurology & Collaborative Innovation Center for Brain Science, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
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31
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Suo G, Cao X, Zheng Y, Li H, Zhang Q, Tang J, Wu Y. A de novo nonsense mutation of STXBP1 causes early-onset epileptic encephalopathy. Epilepsy Behav 2021; 123:108245. [PMID: 34390894 DOI: 10.1016/j.yebeh.2021.108245] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/26/2021] [Accepted: 07/26/2021] [Indexed: 01/16/2023]
Abstract
Mutations in syntaxin-binding protein 1, STXBP1 (also known as MUNC18-1), are linked to multiple neurodevelopmental disorders, including severe early-onset epileptic encephalopathies (EOEEs). A de novo nonsense mutation of STXBP1 (c. 863G > A, p. W288X) was found in a patient diagnosed with EOEE at the age of 17 days. The electroencephalogram (EEG) showed sharp waves and spikes, while brain magnetic resonance imaging was normal. We generated a zebrafish EOEE model by overexpressing mutant STXBP1(W288X) and studied the behavioral changes further to understand the mechanism of W288X mutation in epileptogenesis. In addition, effective antiepileptic drugs were screened in the zebrafish model. Zebrafish STXBP1 homologs were highly conserved and prominently expressed in the larval zebrafish brain. The Tg(hSTXBP1W288X) zebrafish larvae exhibited hyperactivity compared with the wild-type (WT) controls. The expression of STXBP1 decreased during the development course from 1 to 5 days post fertilization. Spontaneous seizures and increased c-fos expression were observed in the mutant zebrafish larvae. The susceptibility of Tg(hSTXBP1W288X) zebrafish to pentylenetetrazol challenge also dramatically increased. Levetiracetam, clonazepam, and topiramate showed antiepileptic effects in the Tg(hSTXBP1W288X) larvae to different extents. Our findings in the newly generated mutant line of zebrafish suggested that zebrafish recapitulated clinical phenotypes associated with human STXBP1 mutation, which provided an appropriate in vivo model for epilepsy research.
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Affiliation(s)
- Guihai Suo
- Department of Pediatrics, Affiliated Hospital of Nantong University, Nantong, China; Department of Neurology, Children's Hospital of Soochow University, Suzhou, China
| | - Xing Cao
- Department of Pediatrics, Affiliated Hospital of Nantong University, Nantong, China
| | - Yuqin Zheng
- Department of Pediatrics, Affiliated Hospital of Nantong University, Nantong, China
| | - Haiying Li
- Department of Pediatrics, Affiliated Hospital of Nantong University, Nantong, China
| | - Qi Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Jihong Tang
- Department of Neurology, Children's Hospital of Soochow University, Suzhou, China
| | - Youjia Wu
- Department of Pediatrics, Affiliated Hospital of Nantong University, Nantong, China
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Mermer F, Poliquin S, Rigsby K, Rastogi A, Shen W, Romero-Morales A, Nwosu G, McGrath P, Demerast S, Aoto J, Bilousova G, Lal D, Gama V, Kang JQ. Common molecular mechanisms of SLC6A1 variant-mediated neurodevelopmental disorders in astrocytes and neurons. Brain 2021; 144:2499-2512. [PMID: 34028503 PMCID: PMC8418336 DOI: 10.1093/brain/awab207] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 05/11/2021] [Accepted: 05/17/2021] [Indexed: 11/13/2022] Open
Abstract
Solute carrier family 6 member 1 (SLC6A1) is abundantly expressed in the developing brain even before the CNS is formed. Its encoded GABA transporter 1 (GAT-1) is responsible for the reuptake of GABA into presynaptic neurons and glia, thereby modulating neurotransmission. GAT-1 is expressed globally in the brain, in both astrocytes and neurons. The GABA uptake function of GAT-1 in neurons cannot be compensated for by other GABA transporters, while the function in glia can be partially replaced by GABA transporter 3. Recently, many variants in SLC6A1 have been associated with a spectrum of epilepsy syndromes and neurodevelopmental disorders, including myoclonic atonic epilepsy, childhood absence epilepsy, autism, and intellectual disability, but the pathomechanisms associated with these phenotypes remain unclear. The presence of GAT-1 in both neurons and astrocytes further obscures the role of abnormal GAT-1 in the heterogeneous disease phenotype manifestations. Here we examine the impact on transporter trafficking and function of 22 SLC6A1 variants identified in patients with a broad spectrum of phenotypes. We also evaluate changes in protein expression and subcellular localization of the variant GAT-1 in various cell types, including neurons and astrocytes derived from human patient induced pluripotent stem cells. We found that a partial or complete loss-of-function represents a common disease mechanism, although the extent of GABA uptake reduction is variable. The reduced GABA uptake appears to be due to reduced cell surface expression of the variant transporter caused by variant protein misfolding, endoplasmic reticulum retention, and subsequent degradation. Although the extent of reduction of the total protein, surface protein, and the GABA uptake level of the variant transporters is variable, the loss of GABA uptake function and endoplasmic reticulum retention is consistent across induced pluripotent stem cell-derived cell types, including astrocytes and neurons, for the surveyed variants. Interestingly, we did not find a clear correlation of GABA uptake function and the disease phenotypes, such as myoclonic atonic epilepsy versus developmental delay, in this study. Together, our study suggests that impaired transporter protein trafficking and surface expression are the major disease-associated mechanisms associated with pathogenic SLC6A1 variants. Our results resemble findings from pathogenic variants in other genes affecting the GABA pathway, such as GABAA receptors. This study provides critical insight into therapeutic developments for SLC6A1 variant-mediated disorders and implicates that boosting transporter function by either genetic or pharmacological approaches would be beneficial.
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Affiliation(s)
- Felicia Mermer
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sarah Poliquin
- Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Brain Institute, Nashville, TN 37232, USA
| | | | - Anuj Rastogi
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Alejandra Romero-Morales
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Stem Cell Biology, Nashville, TN 37232, USA
| | - Gerald Nwosu
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt-Meharry Alliance Vanderbilt University, Nashville, TN 37232, USA
| | - Patrick McGrath
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Scott Demerast
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Jason Aoto
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ganna Bilousova
- Department of Dermatology, Charles C. Gates Center for Regenerative Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Dennis Lal
- Cleveland Clinic Genomic Medicine Institute and Neurological Institute, Cleveland, OH 44195, USA
| | - Vivian Gama
- Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Brain Institute, Nashville, TN 37232, USA
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Center for Stem Cell Biology, Nashville, TN 37232, USA
| | - Jing-Qiong Kang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Brain Institute, Nashville, TN 37232, USA
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Kennedy Center of Human Development, Nashville, TN 37232, USA
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Epileptic Mechanisms Shared by Alzheimer's Disease: Viewed via the Unique Lens of Genetic Epilepsy. Int J Mol Sci 2021; 22:ijms22137133. [PMID: 34281185 PMCID: PMC8268161 DOI: 10.3390/ijms22137133] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/14/2021] [Accepted: 06/15/2021] [Indexed: 12/18/2022] Open
Abstract
Our recent work on genetic epilepsy (GE) has identified common mechanisms between GE and neurodegenerative diseases including Alzheimer's disease (AD). Although both disorders are seemingly unrelated and occur at opposite ends of the age spectrum, it is likely there are shared mechanisms and studies on GE could provide unique insights into AD pathogenesis. Neurodegenerative diseases are typically late-onset disorders, but the underlying pathology may have already occurred long before the clinical symptoms emerge. Pathophysiology in the early phase of these diseases is understudied but critical for developing mechanism-based treatment. In AD, increased seizure susceptibility and silent epileptiform activity due to disrupted excitatory/inhibitory (E/I) balance has been identified much earlier than cognition deficit. Increased epileptiform activity is likely a main pathology in the early phase that directly contributes to impaired cognition. It is an enormous challenge to model the early phase of pathology with conventional AD mouse models due to the chronic disease course, let alone the complex interplay between subclinical nonconvulsive epileptiform activity, AD pathology, and cognition deficit. We have extensively studied GE, especially with gene mutations that affect the GABA pathway such as mutations in GABAA receptors and GABA transporter 1. We believe that some mouse models developed for studying GE and insights gained from GE could provide unique opportunity to understand AD. These include the pathology in early phase of AD, endoplasmic reticulum (ER) stress, and E/I imbalance as well as the contribution to cognitive deficit. In this review, we will focus on the overlapping mechanisms between GE and AD, the insights from mutations affecting GABAA receptors, and GABA transporter 1. We will detail mechanisms of E/I imbalance and the toxic epileptiform generation in AD, and the complex interplay between ER stress, impaired membrane protein trafficking, and synaptic physiology in both GE and AD.
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34
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Carpenter JC, Lignani G. Gene Editing and Modulation: the Holy Grail for the Genetic Epilepsies? Neurotherapeutics 2021; 18:1515-1523. [PMID: 34235638 PMCID: PMC8608979 DOI: 10.1007/s13311-021-01081-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2021] [Indexed: 02/04/2023] Open
Abstract
Epilepsy is a complex neurological disorder for which there are a large number of monogenic subtypes. Monogenic epilepsies are often severe and disabling, featuring drug-resistant seizures and significant developmental comorbidities. These disorders are potentially amenable to a precision medicine approach, of which genome editing using CRISPR/Cas represents the holy grail. Here we consider mutations in some of the most 'common' rare epilepsy genes and discuss the different CRISPR/Cas approaches that could be taken to cure these disorders. We consider scenarios where CRISPR-mediated gene modulation could serve as an effective therapeutic strategy and discuss whether a single gene corrective approach could hold therapeutic potential in the context of homeostatic compensation in the developing, highly dynamic brain. Despite an incomplete understanding of the mechanisms of the genetic epilepsies and current limitations of gene editing tools, CRISPR-mediated approaches have game-changing potential in the treatment of genetic epilepsy over the next decade.
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Affiliation(s)
- Jenna C Carpenter
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, Queen Square House, London, WC1N 3BG, UK
| | - Gabriele Lignani
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, Queen Square House, London, WC1N 3BG, UK.
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Neocortex- and hippocampus-specific deletion of Gabrg2 causes temperature-dependent seizures in mice. Cell Death Dis 2021; 12:553. [PMID: 34050134 PMCID: PMC8163876 DOI: 10.1038/s41419-021-03846-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/17/2021] [Indexed: 02/04/2023]
Abstract
Mutations in the GABRG2 gene encoding the γ-aminobutyric acid (GABA) A receptor gamma 2 subunit are associated with genetic epilepsy with febrile seizures plus, febrile seizures plus, febrile seizures, and other symptoms of epilepsy. However, the mechanisms underlying Gabrg2-mediated febrile seizures are poorly understood. Here, we used the Cre/loxP system to generate conditional knockout (CKO) mice with deficient Gabrg2 in the hippocampus and neocortex. Heterozygous CKO mice (Gabrg2fl/wtCre+) exhibited temperature-dependent myoclonic jerks, generalised tonic-clonic seizures, increased anxiety-like symptoms, and a predisposition to induce seizures. Cortical electroencephalography showed the hyperexcitability in response to temperature elevation in Gabrg2fl/wtCre+ mice, but not in wild-type mice. Gabrg2fl/wtCre+ mice exhibited spontaneous seizures and susceptibility to temperature-induced seizures. Loss of neurons were observed in cortical layers V-VI and hippocampus of Gabrg2fl/wtCre+ mice. Furthermore, the latency of temperature- or pentylenetetrazol-induced seizures were significantly decreased in Gabrg2fl/wtCre+ mice compared with wild-type mice. In summary, Gabrg2fl/wtCre+ mice with Gabrg2 deletion in the neocortex and hippocampus reproduce many features of febrile seizures and therefore provide a novel model to further understand this syndrome at the cellular and molecular level.
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36
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Qu S, Zhou C, Howe R, Shen W, Huang X, Catron M, Hu N, Macdonald RL. The K328M substitution in the human GABA A receptor gamma2 subunit causes GEFS+ and premature sudden death in knock-in mice. Neurobiol Dis 2021; 152:105296. [PMID: 33582225 PMCID: PMC8243844 DOI: 10.1016/j.nbd.2021.105296] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 01/19/2021] [Accepted: 02/08/2021] [Indexed: 01/03/2023] Open
Affiliation(s)
- Shimian Qu
- Departments of Neurology, Vanderbilt University, Nashville, TN 37232, United States of America.
| | - Chengwen Zhou
- Departments of Neurology, Vanderbilt University, Nashville, TN 37232, United States of America.
| | - Rachel Howe
- Departments of Neurology, Vanderbilt University, Nashville, TN 37232, United States of America.
| | - Wangzhen Shen
- Departments of Neurology, Vanderbilt University, Nashville, TN 37232, United States of America.
| | - Xuan Huang
- Departments of Neurology, Vanderbilt University, Nashville, TN 37232, United States of America.
| | - Mackenzie Catron
- Departments of Neurology, Vanderbilt University, Nashville, TN 37232, United States of America.
| | - Ningning Hu
- Departments of Neurology, Vanderbilt University, Nashville, TN 37232, United States of America.
| | - Robert L Macdonald
- Departments of Neurology, Vanderbilt University, Nashville, TN 37232, United States of America; Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, United States of America; Pharmacology, Vanderbilt University, Nashville, TN 37232, United States of America.
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El Achkar CM, Harrer M, Smith L, Kelly M, Iqbal S, Maljevic S, Niturad CE, Vissers LELM, Poduri A, Yang E, Lal D, Lerche H, Møller RS, Olson HE. Characterization of the GABRB2-Associated Neurodevelopmental Disorders. Ann Neurol 2020; 89:573-586. [PMID: 33325057 DOI: 10.1002/ana.25985] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 11/09/2022]
Abstract
OBJECTIVE We aimed to characterize the phenotypic spectrum and functional consequences associated with variants in the gene GABRB2, coding for the γ-aminobutyric acid type A (GABAA ) receptor subunit β2. METHODS We recruited and systematically evaluated 25 individuals with variants in GABRB2, 17 of whom are newly described and 8 previously reported with additional clinical data. Functional analysis was performed using a Xenopus laevis oocyte model system. RESULTS Our cohort of 25 individuals from 22 families with variants in GABRB2 demonstrated a range of epilepsy phenotypes from genetic generalized epilepsy to developmental and epileptic encephalopathy. Fifty-eight percent of individuals had pharmacoresistant epilepsy; response to medications targeting the GABAergic pathway was inconsistent. Developmental disability (present in 84%) ranged from mild intellectual disability to severe global disability; movement disorders (present in 44%) included choreoathetosis, dystonia, and ataxia. Disease-associated variants cluster in the extracellular N-terminus and transmembrane domains 1-3, with more severe phenotypes seen in association with variants in transmembrane domains 1 and 2 and the allosteric binding site between transmembrane domains 2 and 3. Functional analysis of 4 variants in transmembrane domains 1 or 2 (p.Ile246Thr, p.Pro252Leu, p.Ile288Ser, p.Val282Ala) revealed strongly reduced amplitudes of GABA-evoked anionic currents. INTERPRETATION GABRB2-related epilepsy ranges broadly in severity from genetic generalized epilepsy to developmental and epileptic encephalopathies. Developmental disability and movement disorder are key features. The phenotypic spectrum is comparable to other GABAA receptor-encoding genes. Phenotypic severity varies by protein domain. Experimental evidence supports loss of GABAergic inhibition as the mechanism underlying GABRB2-associated neurodevelopmental disorders. ANN NEUROL 2021;89:573-586.
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Affiliation(s)
- Christelle M El Achkar
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - Merle Harrer
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lacey Smith
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA
| | - McKenna Kelly
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Dartmouth Geisel School of Medicine, Hanover, NH
| | - Sumaiya Iqbal
- Center for Development of Therapeutics and Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA
| | - Snezana Maljevic
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Cristina E Niturad
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lisenka E L M Vissers
- Department of Human Genetics, Donders Institute for Brain, Cognition, and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Annapurna Poduri
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
| | - Edward Yang
- Department of Radiology, Boston Children's Hospital, Boston, MA
| | - Dennis Lal
- Cleveland Clinic Genomic Medicine Institute and Neurological Institute, Cleveland, OH
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Heather E Olson
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA.,Department of Neurology, Harvard Medical School, Boston, MA
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38
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Jiang YL, Song C, Wang Y, Zhao J, Yang F, Gao Q, Leng X, Man Y, Jiang W. Clinical Utility of Exome Sequencing and Reinterpreting Genetic Test Results in Children and Adults With Epilepsy. Front Genet 2020; 11:591434. [PMID: 33391346 PMCID: PMC7775549 DOI: 10.3389/fgene.2020.591434] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/30/2020] [Indexed: 11/16/2022] Open
Abstract
The clinical utility of genetic testing for epilepsy has been enhanced with the advancement of next-generation sequencing (NGS) technology along with the rapid updating of publicly available databases. The aim of this study was to evaluate the diagnostic yield of NGS and assess the value of reinterpreting genetic test results in children and adults with epilepsy. We performed genetic testing on 200 patients, including 82 children and 118 adults. The results were classified into three categories: positive, inconclusive, or negative. The reinterpretation of inconclusive results was conducted in April 2020. Overall, we identified disease-causing variants in 12% of the patients in the original analysis, and 14.5% at reinterpretation. The diagnostic yield for adults with epilepsy was similar to that for children (11 vs. 19.5%, p = 0.145). After reinterpretation, 9 of the 86 patients who initially had inconclusive results obtained a clinically significant change in diagnosis. Among these nine revised cases, five obtained positive diagnoses, representing a diagnosis rate of 5.8% (5/86). Manual searches for additional evidence of pathogenicity for candidate variants and updated patient clinical information were the main reasons for diagnostic reclassification. This study emphasizes the diagnostic potential of combining NGS and reinterpretation of inconclusive genetic test reports in children and adults with epilepsy.
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Affiliation(s)
- Yong-Li Jiang
- Department of Neurology, Comprehensive Epilepsy Center, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Changgeng Song
- Department of Neurology, Comprehensive Epilepsy Center, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yuanyuan Wang
- Department of Neurology, Comprehensive Epilepsy Center, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Jingjing Zhao
- Department of Neurology, Comprehensive Epilepsy Center, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Fang Yang
- Department of Neurology, Comprehensive Epilepsy Center, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Qiong Gao
- Department of Neurology, Comprehensive Epilepsy Center, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xiuxiu Leng
- Department of Neurology, Comprehensive Epilepsy Center, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yulin Man
- Department of Neurology, Comprehensive Epilepsy Center, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Wen Jiang
- Department of Neurology, Comprehensive Epilepsy Center, Xijing Hospital, Fourth Military Medical University, Xi'an, China
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Shen D, Chen J, Liu D, Shen M, Wang X, Wu Y, Ke S, Macdonald RL, Zhang Q. The GABRG2 F343L allele causes spontaneous seizures in a novel transgenic zebrafish model that can be treated with suberanilohydroxamic acid (SAHA). ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1560. [PMID: 33437759 PMCID: PMC7791267 DOI: 10.21037/atm-20-3745] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Background Mutations in the γ-aminobutyric acid type A (GABAA) receptor γ2 subunit gene, GABRG2, have been associated frequently with epilepsy syndromes with varying severities. Recently, a de novo GABRG2 mutation, c.T1027C, p.F343L, was identified in a patient with an early onset epileptic encephalopathy (EOEE). In vitro, we demonstrated that GABAA receptors containing the mutant γ2(F343L) subunit have impaired trafficking to the cell surface. Here, we aim to validate an in vivo zebrafish model of EOEE associated with the GABRG2 mutation T1027C. Methods We generated a novel transgenic zebrafish (AB strain) that overexpressed mutant human γ2(F343L) subunits and provided an initial characterization of the transgenic Tg(hGABRG2F343L) zebrafish. Results Real-time quantitative PCR and in situ hybridization identified a significant up-regulation of c-fos in the mutant transgenic zebrafish, which has a well-established role in epileptogenesis. In the larval stage 5 days postfertilization (dpf), freely swimming Tg(hGABRG2F343L) zebrafish displayed spontaneous seizure-like behaviors consisting of whole-body shaking and hyperactivity during automated locomotion video tracking, and seizures can be induced by light stimulation. Using RNA sequencing, we investigated transcriptomic changes due to the presence of mutant γ2L(F343L) subunits and have found 524 genes that are differentially expressed, including up-regulation of 33 genes associated with protein processing. More specifically, protein network analysis indicated histone deacetylases (HDACs) as potential therapeutic targets, and suberanilohydroxamic acid (SAHA), a broad HDACs inhibitor, alleviated seizure-like phenotypes in mutant zebrafish larvae. Conclusions Overall, our Tg(hGABRG2F343L) overexpression zebrafish model provides the first example of a human epilepsy-associated GABRG2 mutation resulting in spontaneous seizures in zebrafish. Moreover, HDAC inhibition may be worth investigating as a therapeutic strategy for genetic epilepsies caused by missense mutations in GABRG2 and possibly in other central nervous system genes that impair surface trafficking.
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Affiliation(s)
- Dingding Shen
- Department of Neurology & Collaborative Innovation Center for Brain Science, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Juan Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Dong Liu
- School of Life Science, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Mi Shen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Xin Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Youjia Wu
- Department of Pediatrics, Affiliated Hospital of Nantong University, Nantong, China
| | - Shuan Ke
- Xinglin College, Nantong University, Nantong, China
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Qi Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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40
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Shen W, Poliquin S, Macdonald RL, Dong M, Kang JQ. Endoplasmic reticulum stress increases inflammatory cytokines in an epilepsy mouse model Gabrg2 +/Q390X knockin: A link between genetic and acquired epilepsy? Epilepsia 2020; 61:2301-2312. [PMID: 32944937 DOI: 10.1111/epi.16670] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/03/2020] [Accepted: 08/03/2020] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Neuroinflammation is a major theme in epilepsy, which has been characterized in acquired epilepsy but is poorly understood in genetic epilepsy. γ-Aminobutyric acid type A receptor subunit gene mutations are significant causes of epilepsy, and we have studied the pathophysiology directly resulting from defective receptor channels. Here, we determined the proinflammatory factors in a genetic mouse model, the Gabrg2+/Q390X knockin (KI). We have identified increased cytokines in multiple brain regions of the KI mouse throughout different developmental stages and propose that accumulation of the trafficking-deficient mutant protein may increase neuroinflammation, which would be a novel mechanism for genetic epilepsy. METHODS We used enzyme-linked immunosorbent assay, immunoprecipitation, nuclei purification, immunoblot, immunohistochemistry, and confocal microscopy to characterize increased neuroinflammation and its potential causes in a Gabrg2+/Q390X KI mouse and a Gabrg2+/- knockout (KO) mouse, each associated with a different epilepsy syndrome with different severities. RESULTS We found that proinflammatory cytokines such as tumor necrosis factor alpha, interleukin 1-beta (IL-1β), and IL-6 were increased in the KI mice but not in the KO mice. A major underlying basis for the discrepancy in cytokine expression between the two mouse models is likely chronic mutant protein accumulation and endoplasmic reticulum (ER) stress. The presence of mutant protein dampened cytokine induction upon further cellular stimulation or external stress such as elevated temperature. Pharmacological induction of ER stress upregulated cytokine expression in the wild-type and KO but not in the KI mice. The increased cytokine expression was independent of seizure occurrence, because it was upregulated in both mice and cultured neurons. SIGNIFICANCE Together, these data demonstrate a novel pathophysiology for genetic epilepsy, increased neuroinflammation, which is a common mechanism for acquired epilepsy. The findings thus provide the first link of neuroinflammation between genetic epilepsy associated with an ion channel gene mutation and acquired epilepsy.
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Affiliation(s)
- Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Sarah Poliquin
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Marco Dong
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jing-Qiong Kang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, USA
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41
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Zhang CQ, Catron MA, Ding L, Hanna CM, Gallagher MJ, Macdonald RL, Zhou C. Impaired State-Dependent Potentiation of GABAergic Synaptic Currents Triggers Seizures in a Genetic Generalized Epilepsy Model. Cereb Cortex 2020; 31:768-784. [PMID: 32930324 DOI: 10.1093/cercor/bhaa256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 08/13/2020] [Accepted: 08/13/2020] [Indexed: 11/14/2022] Open
Abstract
Epileptic activity in genetic generalized epilepsy (GGE) patients preferentially appears during sleep and its mechanism remains unknown. Here, we found that sleep-like slow-wave oscillations (0.5 Hz SWOs) potentiated excitatory and inhibitory synaptic currents in layer V cortical pyramidal neurons from wild-type (wt) mouse brain slices. In contrast, SWOs potentiated excitatory, but not inhibitory, currents in cortical neurons from a heterozygous (het) knock-in (KI) Gabrg2+Q/390X model of Dravet epilepsy syndrome. This created an imbalance between evoked excitatory and inhibitory currents to effectively prompt neuronal action potential firings. Similarly, physiologically similar up-/down-state induction (present during slow-wave sleep) in cortical neurons also potentiated excitatory synaptic currents within brain slices from wt and het KI mice. Moreover, this state-dependent potentiation of excitatory synaptic currents entailed some signaling pathways of homeostatic synaptic plasticity. Consequently, in het KI mice, in vivo SWO induction (using optogenetic methods) triggered generalized epileptic spike-wave discharges (SWDs), being accompanied by sudden immobility, facial myoclonus, and vibrissa twitching. In contrast, in wt littermates, SWO induction did not cause epileptic SWDs and motor behaviors. To our knowledge, this is the first mechanism to explain why epileptic SWDs preferentially happen during non rapid eye-movement sleep and quiet-wakefulness in human GGE patients.
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Affiliation(s)
- Chun-Qing Zhang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Mackenzie A Catron
- Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Li Ding
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Caitlyn M Hanna
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Martin J Gallagher
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robert L Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Chengwen Zhou
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Neuroscience Graduate Program, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Silvennoinen K, Balestrini S, Rothwell JC, Sisodiya SM. Transcranial magnetic stimulation as a tool to understand genetic conditions associated with epilepsy. Epilepsia 2020; 61:1818-1839. [PMID: 32783192 PMCID: PMC8432162 DOI: 10.1111/epi.16634] [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] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/09/2020] [Accepted: 07/09/2020] [Indexed: 12/30/2022]
Abstract
Advances in genetics may enable a deeper understanding of disease mechanisms and promote a shift to more personalised medicine in the epilepsies. At present, understanding of consequences of genetic variants mainly relies on preclinical functional work; tools for acquiring similar data from the living human brain are needed. Transcranial magnetic stimulation (TMS), in particular paired-pulse TMS protocols which depend on the function of cortical GABAergic interneuron networks, has the potential to become such a tool. For this report, we identified and reviewed 23 publications on TMS studies of cortical excitability and inhibition in 15 different genes or conditions relevant to epilepsy. Reduced short-interval intracortical inhibition (SICI) and reduced cortical silent period (CSP) duration were the most commonly reported findings, suggesting abnormal GABAA - (SICI) or GABAB ergic (CSP) signalling. For several conditions, these findings are plausible based on established evidence of involvement of the GABAergic system; for some others, they may inform future research around such mechanisms. Challenges of TMS include lack of complete understanding of the neural underpinnings of the measures used: hypotheses and analyses should be based on existing clinical and preclinical data. Further pitfalls include gathering sufficient numbers of participants, and the effect of confounding factors, especially medications. TMS-EEG is a unique perturbational technique to study the intrinsic properties of the cortex with excellent temporal resolution; while it has the potential to provide further information of use in interpreting effects of genetic variants, currently the links between measures and neurophysiology are less established. Despite these challenges, TMS is a tool with potential for elucidating the system-level in vivo functional consequences of genetic variants in people carrying genetic changes of interest, providing unique insights.
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Affiliation(s)
- Katri Silvennoinen
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Chalfont St. Peter, UK
| | - Simona Balestrini
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Chalfont St. Peter, UK
| | - John C Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, Department of UCL Queen Square, Institute of Neurology, London, UK
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.,Chalfont Centre for Epilepsy, Chalfont St. Peter, UK
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Strickland SL, Reddy JS, Allen M, N'songo A, Burgess JD, Corda MM, Ballard T, Wang X, Carrasquillo MM, Biernacka JM, Jenkins GD, Mukherjee S, Boehme K, Crane P, Kauwe JS, Ertekin‐Taner N. MAPT haplotype-stratified GWAS reveals differential association for AD risk variants. Alzheimers Dement 2020; 16:983-1002. [PMID: 32400971 PMCID: PMC7983911 DOI: 10.1002/alz.12099] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 02/26/2020] [Accepted: 03/06/2020] [Indexed: 12/12/2022]
Abstract
INTRODUCTION MAPT H1 haplotype is implicated as a risk factor for neurodegenerative diseases including Alzheimer's disease (AD). METHODS Using Alzheimer's Disease Genetics Consortium (ADGC) genome-wide association study (GWAS) data (n = 18,841), we conducted a MAPT H1/H2 haplotype-stratified association to discover MAPT haplotype-specific AD risk loci. RESULTS We identified 11 loci-5 in H2-non-carriers and 6 in H2-carriers-although none of the MAPT haplotype-specific associations achieved genome-wide significance. The most significant H2 non-carrier-specific association was with a NECTIN2 intronic (P = 1.33E-07) variant, and that for H2 carriers was near NKX6-1 (P = 1.99E-06). The GABRG2 locus had the strongest epistasis with MAPT H1/H2 variant rs8070723 (P = 3.91E-06). Eight of the 12 genes at these loci had transcriptome-wide significant differential expression in AD versus control temporal cortex (q < 0.05). Six genes were members of the brain transcriptional co-expression network implicated in "synaptic transmission" (P = 9.85E-59), which is also enriched for neuronal genes (P = 1.0E-164), including MAPT. DISCUSSION This stratified GWAS identified loci that may confer AD risk in a MAPT haplotype-specific manner. This approach may preferentially enrich for neuronal genes implicated in synaptic transmission.
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Affiliation(s)
| | - Joseph S. Reddy
- Department of Health Sciences ResearchMayo ClinicJacksonvilleFloridaUSA
| | - Mariet Allen
- Department of NeuroscienceMayo ClinicJacksonvilleFloridaUSA
| | | | | | | | - Travis Ballard
- Department of NeuroscienceMayo ClinicJacksonvilleFloridaUSA
| | - Xue Wang
- Department of Health Sciences ResearchMayo ClinicJacksonvilleFloridaUSA
| | | | | | | | | | | | - Paul Crane
- University of WashingtonSeattleWashingtonUSA
| | | | - Nilüfer Ertekin‐Taner
- Department of NeuroscienceMayo ClinicJacksonvilleFloridaUSA
- Department of NeurologyMayo ClinicJacksonvilleFloridaUSA
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Chow CY, Absalom N, Biggs K, King GF, Ma L. Venom-derived modulators of epilepsy-related ion channels. Biochem Pharmacol 2020; 181:114043. [PMID: 32445870 DOI: 10.1016/j.bcp.2020.114043] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 05/18/2020] [Indexed: 12/18/2022]
Abstract
Epilepsy is characterised by spontaneous recurrent seizures that are caused by an imbalance between neuronal excitability and inhibition. Since ion channels play fundamental roles in the generation and propagation of action potentials as well as neurotransmitter release at a subset of excitatory and inhibitory synapses, their dysfunction has been linked to a wide variety of epilepsies. Indeed, these unique proteins are the major biological targets for antiepileptic drugs. Selective targeting of a specific ion channel subtype remains challenging for small molecules, due to the high level of homology among members of the same channel family. As a consequence, there is a growing trend to target ion channels with biologics. Venoms are the best known natural source of ion channel modulators, and venom peptides are increasingly recognised as potential therapeutics due to their high selectivity and potency gained through millions of years of evolutionary selection pressure. Here we describe the major ion channel families involved in the pathogenesis of various types of epilepsy, including voltage-gated Na+, K+, Ca2+ channels, Cys-loop receptors, ionotropic glutamate receptors and P2X receptors, and currently available venom-derived peptides that target these channel proteins. Although only a small number of venom peptides have successfully progressed to the clinic, there is reason to be optimistic about their development as antiepileptic drugs, notwithstanding the challenges associated with development of any class of peptide drug.
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Affiliation(s)
- Chun Yuen Chow
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Nathan Absalom
- Brain and Mind Centre, School of Pharmacy, Faculty of Health and Medicine, The University of Sydney, Sydney, NSW 2050, Australia
| | - Kimberley Biggs
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Linlin Ma
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia.
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GABRG2 Deletion Linked to Genetic Epilepsy with Febrile Seizures Plus Affects the Expression of GABA A Receptor Subunits and Other Genes at Different Temperatures. Neuroscience 2020; 438:116-136. [PMID: 32418750 DOI: 10.1016/j.neuroscience.2020.04.049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 04/29/2020] [Accepted: 04/30/2020] [Indexed: 12/11/2022]
Abstract
Mutations in γ-aminobutyric acid A receptor (GABAA) subunits and sodium channel genes, especially GABRG2 and SCN1A, have been reported to be associated with febrile seizures (FS) and genetic epilepsy with febrile seizures plus (GEFS+). GEFS+ is a well-known family of epileptic syndrome with autosomal dominant inheritance in children. Its most common phenotypes are febrile seizures often with accessory afebrile generalized tonic-clonic seizures, febrile seizures plus (FS+), severe epileptic encephalopathy, as well as other types of generalized or localization-related seizures. However, the pathogenesis of febrile seizures remains largely unknown. Here, we generated a GABRG2 gene knockout cell line (HT22GABRG2KO) by applying the CRISPR/Cas9-mediated genomic deletion in HT-22 mouse hippocampal neuronal cell line to explore the function of GABRG2 in vitro. With mRNA-seq, we found significant changes in the expression profiles of several epilepsy-related genes when GABRG2 was knockout, some of them showing temperature-induced changes as well. Kyoto Encyclopedia Gene and Genomic (KEGG) analysis revealed a significant alteration in the MAPK and PI3K-Akt signaling pathways. We also observed an up-regulation of the matrix metalloproteinases (MMPs) family after GABRG2 knockout. Furthermore, the significant decrease in expression of GABRA1 and CACNA1A (but not others) with an increase in temperature is a novel finding. In summary, mutations in the GABAA receptor can lead to a decrease in numbers of receptors, which may cause the impairment of GABAergic pathway signaling. This data has been the first time to reveal that GABRG2 mutations would affect the function of other genes, and based on this finding we hope this work would also provide a new direction for the research of GABRG2 in GEFS+. It also may provide a molecular basis for the severity of epilepsy, and guide the clinical medication for the treatment of the epilepsy focused on the function on GABAA receptors, which, might be a new strategy for genetic diagnosis and targeted treatment of epilepsy.
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Maljevic S, Keren B, Aung YH, Forster IC, Mignot C, Buratti J, Lafitte A, Freihuber C, Rodan LH, Bergin A, Hubert L, Poirier K, Munnich A, Besmond C, Hauser N, Miller R, McWalter K, Nabbout R, Héron D, Leguern E, Depienne C, Petrou S, Nava C. Novel GABRA2 variants in epileptic encephalopathy and intellectual disability with seizures. Brain 2020; 142:e15. [PMID: 31032849 DOI: 10.1093/brain/awz079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Boris Keren
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France
| | - Ye Htet Aung
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Ian C Forster
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Cyril Mignot
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France.,Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
| | - Julien Buratti
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France
| | - Aurélie Lafitte
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France
| | - Cécile Freihuber
- AP-HP, Hôpital Trousseau, Service de Neuropédiatrie, Paris, France
| | - Lance H Rodan
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ann Bergin
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Laurence Hubert
- INSERM UMR 1163, Translational Genetics Lab., Paris-Descartes University, Imagine Institute, Paris, France
| | - Karine Poirier
- INSERM UMR 1163, Translational Genetics Lab., Paris-Descartes University, Imagine Institute, Paris, France
| | - Arnold Munnich
- INSERM UMR 1163, Translational Genetics Lab., Paris-Descartes University, Imagine Institute, Paris, France
| | - Claude Besmond
- INSERM UMR 1163, Translational Genetics Lab., Paris-Descartes University, Imagine Institute, Paris, France
| | - Natalie Hauser
- Inova Health System, Inova Translational Medicine Institute, Falls Church, VA, USA
| | - Rebecca Miller
- Inova Health System, Inova Translational Medicine Institute, Falls Church, VA, USA
| | | | - Rima Nabbout
- APHP, Hôpital Necker Enfants Malades, Centre de référence épilepsies rares, Service de Neurologie pédiatrique, Paris, France
| | - Delphine Héron
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France
| | - Eric Leguern
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France.,Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
| | - Christel Depienne
- Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France.,Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Caroline Nava
- APHP, Hôpital Pitié-Salpêtrière, Département de Génétique, Centre de Reference Déficience Intellectuelle de Causes Rares, GRC UPMC «Déficience Intellectuelle et Autisme», Paris, France.,Sorbonne Universités, Institut du Cerveau et de la Moelle épinière, ICM, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
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Cárdenas-Rodríguez N, Carmona-Aparicio L, Pérez-Lozano DL, Ortega-Cuellar D, Gómez-Manzo S, Ignacio-Mejía I. Genetic variations associated with pharmacoresistant epilepsy (Review). Mol Med Rep 2020; 21:1685-1701. [PMID: 32319641 PMCID: PMC7057824 DOI: 10.3892/mmr.2020.10999] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 01/16/2020] [Indexed: 12/13/2022] Open
Abstract
Epilepsy is a common, serious neurological disorder worldwide. Although this disease can be successfully treated in most cases, not all patients respond favorably to medical treatments, which can lead to pharmacoresistant epilepsy. Drug-resistant epilepsy can be caused by a number of mechanisms that may involve environmental and genetic factors, as well as disease- and drug-related factors. In recent years, numerous studies have demonstrated that genetic variation is involved in the drug resistance of epilepsy, especially genetic variations found in drug resistance-related genes, including the voltage-dependent sodium and potassium channels genes, and the metabolizer of endogenous and xenobiotic substances genes. The present review aimed to highlight the genetic variants that are involved in the regulation of drug resistance in epilepsy; a comprehensive understanding of the role of genetic variation in drug resistance will help us develop improved strategies to regulate drug resistance efficiently and determine the pathophysiological processes that underlie this common human neurological disease.
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Affiliation(s)
- Noemí Cárdenas-Rodríguez
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Liliana Carmona-Aparicio
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Diana L Pérez-Lozano
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Daniel Ortega-Cuellar
- Laboratory of Experimental Nutrition, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Saúl Gómez-Manzo
- Laboratory of Genetic Biochemistry, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Iván Ignacio-Mejía
- Laboratory of Translational Medicine, Military School of Health Graduates, Lomas de Sotelo, Militar, Mexico City 11200, Mexico
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Papandreou A, Danti FR, Spaull R, Leuzzi V, Mctague A, Kurian MA. The expanding spectrum of movement disorders in genetic epilepsies. Dev Med Child Neurol 2020; 62:178-191. [PMID: 31784983 DOI: 10.1111/dmcn.14407] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/01/2019] [Indexed: 12/27/2022]
Abstract
An ever-increasing number of neurogenetic conditions presenting with both epilepsy and atypical movements are now recognized. These disorders within the 'genetic epilepsy-dyskinesia' spectrum are clinically and genetically heterogeneous. Increased clinical awareness is therefore necessary for a rational diagnostic approach. Furthermore, careful interpretation of genetic results is key to establishing the correct diagnosis and initiating disease-specific management strategies in a timely fashion. In this review we describe the spectrum of movement disorders associated with genetically determined epilepsies. We also propose diagnostic strategies and putative pathogenic mechanisms causing these complex syndromes associated with both seizures and atypical motor control. WHAT THIS PAPER ADDS: Implicated genes encode proteins with very diverse functions. Pathophysiological mechanisms by which epilepsy and movement disorder phenotypes manifest are often not clear. Early diagnosis of treatable disorders is essential and next generation sequencing may be required.
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Affiliation(s)
- Apostolos Papandreou
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Federica Rachele Danti
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Robert Spaull
- Department of Paediatric Neurology, Bristol Royal Hospital for Children, Bristol, UK
- Bristol Medical School, University of Bristol, Bristol, UK
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Amy Mctague
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Manju A Kurian
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
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Kim G, Kim Y, Yoon S, Kim S, Yi SS. Sleep-inducing effect of Passiflora incarnata L. extract by single and repeated oral administration in rodent animals. Food Sci Nutr 2020; 8:557-566. [PMID: 31993179 PMCID: PMC6977488 DOI: 10.1002/fsn3.1341] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 09/29/2019] [Accepted: 10/05/2019] [Indexed: 11/28/2022] Open
Abstract
Social cost of insomnia in modern society is gradually increasing. Due to various social phenomena and lifestyles that take away the opportunity of good quality of sleep, problems of insomnia cannot be easily figured out. Prescription of sleeping pills for insomnia patients can cause other inconveniences due to their side effects beyond their intended purposes. On the other hand, Passiflora incarnata L. (PI) has been widely used in South America for several centuries, showing effectiveness for sleep, sedation, anxiety, and so on in the civilian population. However, reports on the treatment efficacy of this herbal medicinal plant for insomnia patients through standardization as a sleeping agent have been very rare. Therefore, we obtained leaves and fruits of PI (8:2 by weight) as powder to prepare an extract. It was then applied to C6 rat glioma cells to quantitate mRNA expression levels of GABA receptors. Its sleep-inducing effect was investigated using experimental animals. PI extract (6 μg/ml) significantly decreased GABA receptors at 6 hr after treatment. Immobility time and palpebral closing time were significantly increased after single (500 mg/kg) or repeated (250 mg/kg) oral administration. In addition, blood melatonin levels were significantly increased in PI extract-treated animals after both single and repeated administrations. These results were confirmed through several repeated experiments. Taken together, these results confirmed that PI extract had significant sleep-inducing effects in cells and animals, suggesting that PI extract might have potential for treating human insomnia.
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Affiliation(s)
- Gwang‐Ho Kim
- Department of Biomedical Laboratory ScienceCollege of Medical SciencesSoonchunhyang UniversityAsanKorea
| | - Yehlim Kim
- Department of Biomedical Laboratory ScienceCollege of Medical SciencesSoonchunhyang UniversityAsanKorea
| | - Sunmi Yoon
- Department of Biomedical Laboratory ScienceCollege of Medical SciencesSoonchunhyang UniversityAsanKorea
| | - Sung‐Jo Kim
- Department of BiotechnologyHoseo UniversityAsanKorea
| | - Sun Shin Yi
- Department of Biomedical Laboratory ScienceCollege of Medical SciencesSoonchunhyang UniversityAsanKorea
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Mild chronic perturbation of inhibition severely alters hippocampal function. Sci Rep 2019; 9:16431. [PMID: 31712706 PMCID: PMC6848214 DOI: 10.1038/s41598-019-52851-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/21/2019] [Indexed: 02/07/2023] Open
Abstract
Pentameric GABAA receptors mediate a large share of CNS inhibition. The γ2 subunit is a typical constituent. At least 11 mutations in the γ2 subunit cause human epilepsies, making the role of γ2-containing receptors in brain function of keen basic and translational interest. How small changes to inhibition may cause brain abnormalities, including seizure disorders, is unclear. In mice, we perturbed fast inhibition with a point mutation T272Y (T6′Y in the second membrane-spanning domain) to the γ2 subunit. The mutation imparts resistance to the GABAA receptor antagonist picrotoxin, allowing verification of mutant subunit incorporation. We confirmed picrotoxin resistance and biophysical properties in recombinant receptors. T6′Y γ2-containing receptors also exhibited faster deactivation but unaltered steady-state properties. Adult T6′Y knockin mice exhibited myoclonic seizures and abnormal cortical EEG, including abnormal hippocampal-associated theta oscillations. In hippocampal slices, picrotoxin-insensitive inhibitory synaptic currents exhibited fast decay. Excitatory/inhibitory balance was elevated by an amount expected from the IPSC alteration. Partial pharmacological correction of γ2-mediated IPSCs with diazepam restored total EEG power toward baseline, but had little effect on the abnormal low-frequency peak in the EEG. The results suggest that at least part of the abnormality in brain function arises from the acute effects of truncated inhibition.
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