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He MF, Liu LH, Luo S, Wang J, Guo JJ, Wang PY, Zhai QX, He SL, Zou DF, Liu XR, Li BM, Ma HY, Qiao JD, Zhou P, He N, Yi YH, Liao WP. ZFHX3 variants cause childhood partial epilepsy and infantile spasms with favourable outcomes. J Med Genet 2024; 61:652-660. [PMID: 38508705 PMCID: PMC11228202 DOI: 10.1136/jmg-2023-109725] [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: 11/01/2023] [Accepted: 02/18/2024] [Indexed: 03/22/2024]
Abstract
BACKGROUND The ZFHX3 gene plays vital roles in embryonic development, cell proliferation, neuronal differentiation and neuronal death. This study aims to explore the relationship between ZFHX3 variants and epilepsy. METHODS Whole-exome sequencing was performed in a cohort of 378 patients with partial (focal) epilepsy. A Drosophila Zfh2 knockdown model was used to validate the association between ZFHX3 and epilepsy. RESULTS Compound heterozygous ZFHX3 variants were identified in eight unrelated cases. The burden of ZFHX3 variants was significantly higher in the case cohort, shown by multiple/specific statistical analyses. In Zfh2 knockdown flies, the incidence and duration of seizure-like behaviour were significantly greater than those in the controls. The Zfh2 knockdown flies exhibited more firing in excitatory neurons. All patients presented partial seizures. The five patients with variants in the C-terminus/N-terminus presented mild partial epilepsy. The other three patients included one who experienced frequent non-convulsive status epilepticus and two who had early spasms. These three patients had also neurodevelopmental abnormalities and were diagnosed as developmental epileptic encephalopathy (DEE), but achieved seizure-free after antiepileptic-drug treatment without adrenocorticotropic-hormone/steroids. The analyses of temporal expression (genetic dependent stages) indicated that ZFHX3 orthologous were highly expressed in the embryonic stage and decreased dramatically after birth. CONCLUSION ZFHX3 is a novel causative gene of childhood partial epilepsy and DEE. The patients of infantile spasms achieved seizure-free after treatment without adrenocorticotropic-hormone/steroids implies a significance of genetic diagnosis in precise treatment. The genetic dependent stage provided an insight into the underlying mechanism of the evolutional course of illness.
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Affiliation(s)
- Ming-Feng He
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Li-Hong Liu
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
- Department of Neurology, Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510630, China
| | - Sheng Luo
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Juan Wang
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Jia-Jun Guo
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Peng-Yu Wang
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Qiong-Xiang Zhai
- Department of Pediatrics, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510120, China
| | - Su-Li He
- Department of Pediatrics, Shantou Chaonan Minsheng Hospital, Shantou 515000, China
| | - Dong-Fang Zou
- Epilepsy Center and Department of Neurology, Shenzhen Children's Hospital, Shenzhen 518029, China
| | - Xiao-Rong Liu
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Bing-Mei Li
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Hai-Yan Ma
- Department of Functional Neurosurgery, Affiliated Nanjing Brain Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Jing-Da Qiao
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Peng Zhou
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Na He
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Yong-Hong Yi
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Wei-Ping Liao
- Department of Neurology, Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
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Kellner S, Berlin S. Rescuing tri-heteromeric NMDA receptor function: the potential of pregnenolone-sulfate in loss-of-function GRIN2B variants. Cell Mol Life Sci 2024; 81:235. [PMID: 38795169 PMCID: PMC11127902 DOI: 10.1007/s00018-024-05243-x] [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: 10/09/2023] [Revised: 04/16/2024] [Accepted: 04/18/2024] [Indexed: 05/27/2024]
Abstract
N-methyl-D-aspartate receptors (NMDARs emerging from GRIN genes) are tetrameric receptors that form diverse channel compositions in neurons, typically consisting of two GluN1 subunits combined with two GluN2(A-D) subunits. During prenatal stages, the predominant channels are di-heteromers with two GluN1 and two GluN2B subunits due to the high abundance of GluN2B subunits. Postnatally, the expression of GluN2A subunits increases, giving rise to additional subtypes, including GluN2A-containing di-heteromers and tri-heteromers with GluN1, GluN2A, and GluN2B subunits. The latter emerge as the major receptor subtype at mature synapses in the hippocampus. Despite extensive research on purely di-heteromeric receptors containing two identical GRIN variants, the impact of a single variant on the function of other channel forms, notably tri-heteromers, is lagging. In this study, we systematically investigated the effects of two de novo GRIN2B variants (G689C and G689S) in pure, mixed di- and tri-heteromers. Our findings reveal that incorporating a single variant in mixed di-heteromers or tri-heteromers exerts a dominant negative effect on glutamate potency, although 'mixed' channels show improved potency compared to pure variant-containing di-heteromers. We show that a single variant within a receptor complex does not impair the response of all receptor subtypes to the positive allosteric modulator pregnenolone-sulfate (PS), whereas spermine completely fails to potentiate tri-heteromers containing GluN2A and -2B-subunits. We examined PS on primary cultured hippocampal neurons transfected with the variants, and observed a positive impact over current amplitudes and synaptic activity. Together, our study supports previous observations showing that mixed di-heteromers exhibit improved glutamate potency and extend these findings towards the exploration of the effect of Loss-of-Function variants over tri-heteromers. Notably, we provide an initial and crucial demonstration of the beneficial effects of GRIN2B-relevant potentiators on tri-heteromers. Our results underscore the significance of studying how different variants affect distinct receptor subtypes, as these effects cannot be inferred solely from observations made on pure di-heteromers. Overall, this study contributes to ongoing efforts to understand the pathophysiology of GRINopathies and provides insights into potential treatment strategies.
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Affiliation(s)
- Shai Kellner
- Dept. of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, 1 Efron Bat Galim, Haifa, 3525433, Israel
| | - Shai Berlin
- Dept. of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, 1 Efron Bat Galim, Haifa, 3525433, Israel.
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3
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Montanucci L, Brünger T, Bhattarai N, Boßelmann CM, Kim S, Allen JP, Zhang J, Klöckner C, Fariselli P, May P, Lemke JR, Myers SJ, Yuan H, Traynelis SF, Lal D. Distances from ligands as main predictive features for pathogenicity and functional effect of variants in NMDA receptors. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.06.24306939. [PMID: 38766179 PMCID: PMC11100844 DOI: 10.1101/2024.05.06.24306939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Genetic variants in genes GRIN1 , GRIN2A , GRIN2B , and GRIN2D , which encode subunits of the N-methyl-D-aspartate receptor (NMDAR), have been associated with severe and heterogeneous neurologic diseases. Missense variants in these genes can result in gain or loss of the NMDAR function, requiring opposite therapeutic treatments. Computational methods that predict pathogenicity and molecular functional effects are therefore crucial for accurate diagnosis and therapeutic applications. We assembled missense variants: 201 from patients, 631 from general population, and 159 characterized by electrophysiological readouts showing whether they can enhance or reduce the receptor function. This includes new functional data from 47 variants reported here, for the first time. We found that pathogenic/benign variants and variants that increase/decrease the channel function were distributed unevenly on the protein structure, with spatial proximity to ligands bound to the agonist and antagonist binding sites being key predictive features. Leveraging distances from ligands, we developed two independent machine learning-based predictors for NMDAR missense variants: a pathogenicity predictor which outperforms currently available predictors (AUC=0.945, MCC=0.726), and the first binary predictor of molecular function (increase or decrease) (AUC=0.809, MCC=0.523). Using these, we reclassified variants of uncertain significance in the ClinVar database and refined a previous genome-informed epidemiological model to estimate the birth incidence of molecular mechanism-defined GRIN disorders. Our findings demonstrate that distance from ligands is an important feature in NMDARs that can enhance variant pathogenicity prediction and enable functional prediction. Further studies with larger numbers of phenotypically and functionally characterized variants will enhance the potential clinical utility of this method.
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Lee S, Jung WB, Moon H, Im GH, Noh YW, Shin W, Kim YG, Yi JH, Hong SJ, Jung Y, Ahn S, Kim SG, Kim E. Anterior cingulate cortex-related functional hyperconnectivity underlies sensory hypersensitivity in Grin2b-mutant mice. Mol Psychiatry 2024:10.1038/s41380-024-02572-y. [PMID: 38704508 DOI: 10.1038/s41380-024-02572-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 05/06/2024]
Abstract
Sensory abnormalities are observed in ~90% of individuals with autism spectrum disorders (ASD), but the underlying mechanisms are poorly understood. GluN2B, an NMDA receptor subunit that regulates long-term depression and circuit refinement during brain development, has been strongly implicated in ASD, but whether GRIN2B mutations lead to sensory abnormalities remains unclear. Here, we report that Grin2b-mutant mice show behavioral sensory hypersensitivity and brain hyperconnectivity associated with the anterior cingulate cortex (ACC). Grin2b-mutant mice with a patient-derived C456Y mutation (Grin2bC456Y/+) show sensory hypersensitivity to mechanical, thermal, and electrical stimuli through supraspinal mechanisms. c-fos and functional magnetic resonance imaging indicate that the ACC is hyperactive and hyperconnected with other brain regions under baseline and stimulation conditions. ACC pyramidal neurons show increased excitatory synaptic transmission. Chemogenetic inhibition of ACC pyramidal neurons normalizes ACC hyperconnectivity and sensory hypersensitivity. These results suggest that GluN2B critically regulates ASD-related cortical connectivity and sensory brain functions.
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Affiliation(s)
- Soowon Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea
- Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, 13620, Korea
| | - Won Beom Jung
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Korea
- Emotion, Cognition & Behavior Research Group, Korea Brain Research Institute (KBRI), Daegu, 41062, Korea
| | - Heera Moon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea
| | - Geun Ho Im
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Korea
| | - Young Woo Noh
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Wangyong Shin
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Yong Gyu Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Jee Hyun Yi
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea
| | - Seok Jun Hong
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, 16419, Korea
| | - Yongwhan Jung
- Therapeutics and Biotechnology Division, Korea Research Institute of Chemical Technology (KRICT), Daejeon, 34114, Korea
| | - Sunjoo Ahn
- Therapeutics and Biotechnology Division, Korea Research Institute of Chemical Technology (KRICT), Daejeon, 34114, Korea
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, 16419, Korea.
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, 16419, Korea.
- Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon, 16419, Korea.
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea.
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141, Korea.
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5
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Kolosky T, Erdemir G. A novel GRIN2B variant (p.F1340V) causes a severe neurodevelopmental disorder with refractory epileptic spasms. Epileptic Disord 2024. [PMID: 38411992 DOI: 10.1002/epd2.20210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 01/24/2024] [Accepted: 02/09/2024] [Indexed: 02/28/2024]
Affiliation(s)
- Taylor Kolosky
- University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Gozde Erdemir
- Division of Pediatric Neurology and Department of Neurology, University of Maryland Medical Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
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6
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Snyder HE, Jain P, RamachandranNair R, Jones KC, Whitney R. Genetic Advancements in Infantile Epileptic Spasms Syndrome and Opportunities for Precision Medicine. Genes (Basel) 2024; 15:266. [PMID: 38540325 PMCID: PMC10970414 DOI: 10.3390/genes15030266] [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: 01/19/2024] [Revised: 02/13/2024] [Accepted: 02/20/2024] [Indexed: 06/15/2024] Open
Abstract
Infantile epileptic spasms syndrome (IESS) is a devastating developmental epileptic encephalopathy (DEE) consisting of epileptic spasms, as well as one or both of developmental regression or stagnation and hypsarrhythmia on EEG. A myriad of aetiologies are associated with the development of IESS; broadly, 60% of cases are thought to be structural, metabolic or infectious in nature, with the remainder genetic or of unknown cause. Epilepsy genetics is a growing field, and over 28 copy number variants and 70 single gene pathogenic variants related to IESS have been discovered to date. While not exhaustive, some of the most commonly reported genetic aetiologies include trisomy 21 and pathogenic variants in genes such as TSC1, TSC2, CDKL5, ARX, KCNQ2, STXBP1 and SCN2A. Understanding the genetic mechanisms of IESS may provide the opportunity to better discern IESS pathophysiology and improve treatments for this condition. This narrative review presents an overview of our current understanding of IESS genetics, with an emphasis on animal models of IESS pathogenesis, the spectrum of genetic aetiologies of IESS (i.e., chromosomal disorders, single-gene disorders, trinucleotide repeat disorders and mitochondrial disorders), as well as available genetic testing methods and their respective diagnostic yields. Future opportunities as they relate to precision medicine and epilepsy genetics in the treatment of IESS are also explored.
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Affiliation(s)
- Hannah E. Snyder
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
| | - Puneet Jain
- Division of Neurology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON M5G 1E8, Canada
| | - Rajesh RamachandranNair
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
| | - Kevin C. Jones
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
| | - Robyn Whitney
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
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7
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Ng ACH, Choudhary A, Barrett KT, Gavrilovici C, Scantlebury MH. Mechanisms of infantile epileptic spasms syndrome: What have we learned from animal models? Epilepsia 2024; 65:266-280. [PMID: 38036453 DOI: 10.1111/epi.17841] [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: 10/02/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 12/02/2023]
Abstract
The devastating developmental and epileptic encephalopathy of infantile epileptic spasms syndrome (IESS) has numerous causes, including, but not limited to, brain injury, metabolic, and genetic conditions. Given the stereotyped electrophysiologic, age-dependent, and clinical findings, there likely exists one or more final common pathways in the development of IESS. The identity of this final common pathway is unknown, but it may represent a novel therapeutic target for infantile spasms. Previous research on IESS has focused largely on identifying the neuroanatomic substrate using specialized neuroimaging techniques and cerebrospinal fluid analysis in human patients. Over the past three decades, several animal models of IESS were created with an aim to interrogate the underlying pathogenesis of IESS, to identify novel therapeutic targets, and to test various treatments. Each of these models have been successful at recapitulating multiple aspects of the human IESS condition. These animal models have implicated several different molecular pathways in the development of infantile spasms. In this review we outline the progress that has been made thus far using these animal models and discuss future directions to help researchers identify novel treatments for drug-resistant IESS.
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Affiliation(s)
- Andy Cheuk-Him Ng
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Anamika Choudhary
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Karlene T Barrett
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Cezar Gavrilovici
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Morris H Scantlebury
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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8
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den Hollander B, Rothuizen-Lindenschot M, Geertjens L, Vaz FM, Brands MM, Le HL, van Eeghen AM, van de Ven PM, Cornel MC, Jacobs BA, Bruining H, van Karnebeek CD. Effectiveness of L-serine supplementation in children with a GRIN2B loss-of-function mutation: Rationale and protocol for single patient (n-of-1) multiple cross-over trials. Contemp Clin Trials Commun 2023; 36:101233. [PMID: 38144875 PMCID: PMC10746402 DOI: 10.1016/j.conctc.2023.101233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/20/2023] [Accepted: 11/12/2023] [Indexed: 12/26/2023] Open
Abstract
Rationale Loss-of-function (LoF) mutations in GRIN2B result in neurologic abnormalities due to N-methyl-D-aspartate receptor (NMDAR) dysfunction. Affected persons present with various symptoms, including intellectual developmental disability (IDD), hypotonia, communication deficits, motor impairment, complex behavior, seizures, sleep disorders and gastrointestinal disturbance. Recently, in vitro experiments showed that D-serine mitigates function to GluN2B (mutation)-containing NMDARs. 11 previous case reports are published on (experimental) L-serine treatment of patients between 1.5 and 12 years old with GRIN2B missense or null mutations, some of whom showed notable improvement in motor and cognitive performance, communication, behavior and abnormalities on electro encephalography (EEG). Our objective is to further evaluate the effectiveness of L-serine for GRIN2B-related neurodevelopmental disorder (GRIN2B-NDD), using an n-of-1 trial design, increasing the level of evidence. Methods/design These n-of-1 trials, consisting of 2 cycles of 6 months, will be performed to evaluate the effect of L-serine compared to placebo in 4 patients with a GRIN2B LoF mutation. The aggregation of multiple n-of-1 trials will provide an estimate of the average treatment effects.The primary outcome is the Perceive-Recall-Plan-Perform of Task Analysis, assessing developmental skills. Secondary outcomes include Goal Attainment Scaling, seizure log books, EEGs, sleep log books, the irritability subscale of the Aberrant Behavior Checklist, the Bristol Stool Scale and the Pediatric Quality of Life Inventory. Conclusion This study employs an innovative methodological approach to evaluate the effectiveness of L-serine for patients with a GRIN2B LoF mutation. The results will establish a foundation for implementing L-serine as a disease-modifying treatment in GRIN2B-NDD.
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Affiliation(s)
- Bibiche den Hollander
- Amsterdam UMC Location University of Amsterdam, Department of Pediatrics, Emma Children's Hospital, Amsterdam Gastroenterology Endocrinology Metabolism, Meibergdreef 9, Amsterdam, the Netherlands
- Emma Personalized Medicine Center, Amsterdam UMC, Amsterdam, the Netherlands
- United for Metabolic Diseases, Amsterdam, the Netherlands
| | | | - Lisa Geertjens
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Child and Adolescent Psychiatry and Psychosocial Care, Emma Children's Hospital, Boelelaan 1117, Amsterdam, the Netherlands
- Amsterdam UMC Location University of Amsterdam, N=You Neurodevelopmental Precision Center, Amsterdam Neuroscience, Amsterdam Reproduction and Development, Meibergdreef 9, Amsterdam, the Netherlands
| | - Frédéric M. Vaz
- United for Metabolic Diseases, Amsterdam, the Netherlands
- Amsterdam UMC Location University of Amsterdam, Department of Clinical Chemistry and Pediatrics, Laboratory Genetic Metabolic Diseases, Emma Children's Hospital, Meibergdreef 9, Amsterdam, the Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Inborn Errors of Metabolism, Amsterdam, the Netherlands
- Amsterdam UMC Location University of Amsterdam, Department of Core Facility Metabolomics, Meibergdreef 9, Amsterdam, the Netherlands
| | - Marion M. Brands
- Amsterdam UMC Location University of Amsterdam, Department of Pediatrics, Emma Children's Hospital, Amsterdam Gastroenterology Endocrinology Metabolism, Meibergdreef 9, Amsterdam, the Netherlands
- Emma Personalized Medicine Center, Amsterdam UMC, Amsterdam, the Netherlands
- United for Metabolic Diseases, Amsterdam, the Netherlands
| | - Hoang Lan Le
- Amsterdam UMC Location University of Amsterdam, Department of Hospital Pharmacy, Meibergdreef 9, Amsterdam, the Netherlands
- Medicine for Society, Platform at Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Agnies M. van Eeghen
- Emma Personalized Medicine Center, Amsterdam UMC, Amsterdam, the Netherlands
- Advisium, ‘s Heerlen Loo Zorggroep, Amersfoort, the Netherlands
- Amsterdam UMC location University of Amsterdam, Department of Pediatrics, Emma Children’s Hospital, Amsterdam Public Health Research Institute, Methodology and Mental Health and Personalized Medicine, Meibergdreef 9, Amsterdam, the Netherlands
- Amsterdam UMC location University of Amsterdam, Department of Pediatrics, Emma Children’s Hospital, Amsterdam Reproduction & Development, Child Development, Meibergdreef 9, Amsterdam, the Netherlands
| | - Peter M. van de Ven
- University Medical Center Utrecht, Department of Data Science and Biostatistics, Julius Center for Health Sciences and Primary Care, Heidelberglaan 100, Utrecht, the Netherlands
| | - Martina C. Cornel
- Emma Personalized Medicine Center, Amsterdam UMC, Amsterdam, the Netherlands
- Amsterdam UMC Location Vrije Universiteit van Amsterdam, Department of Human Genetics, Amsterdam Reproduction and Development, Meibergdreef 9, Amsterdam, the Netherlands
| | - Bart A.W. Jacobs
- Medicine for Society, Platform at Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
- Antoni van Leeuwenhoek, Department of Pharmacy and Clinical Pharmacology, Plesmanlaan 121, Amsterdam, the Netherlands
| | - Hilgo Bruining
- Emma Personalized Medicine Center, Amsterdam UMC, Amsterdam, the Netherlands
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Child and Adolescent Psychiatry and Psychosocial Care, Emma Children's Hospital, Boelelaan 1117, Amsterdam, the Netherlands
- Amsterdam UMC Location University of Amsterdam, N=You Neurodevelopmental Precision Center, Amsterdam Neuroscience, Amsterdam Reproduction and Development, Meibergdreef 9, Amsterdam, the Netherlands
| | - Clara D. van Karnebeek
- Amsterdam UMC Location University of Amsterdam, Department of Pediatrics, Emma Children's Hospital, Amsterdam Gastroenterology Endocrinology Metabolism, Meibergdreef 9, Amsterdam, the Netherlands
- Emma Personalized Medicine Center, Amsterdam UMC, Amsterdam, the Netherlands
- United for Metabolic Diseases, Amsterdam, the Netherlands
- Amsterdam UMC Location Vrije Universiteit van Amsterdam, Department of Human Genetics, Amsterdam Reproduction and Development, Meibergdreef 9, Amsterdam, the Netherlands
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Bortolami A, Sesti F. Ion channels in neurodevelopment: lessons from the Integrin-KCNB1 channel complex. Neural Regen Res 2023; 18:2365-2369. [PMID: 37282454 PMCID: PMC10360111 DOI: 10.4103/1673-5374.371347] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Abstract
Ion channels modulate cellular excitability by regulating ionic fluxes across biological membranes. Pathogenic mutations in ion channel genes give rise to epileptic disorders that are among the most frequent neurological diseases affecting millions of individuals worldwide. Epilepsies are triggered by an imbalance between excitatory and inhibitory conductances. However, pathogenic mutations in the same allele can give rise to loss-of-function and/or gain-of-function variants, all able to trigger epilepsy. Furthermore, certain alleles are associated with brain malformations even in the absence of a clear electrical phenotype. This body of evidence argues that the underlying epileptogenic mechanisms of ion channels are more diverse than originally thought. Studies focusing on ion channels in prenatal cortical development have shed light on this apparent paradox. The picture that emerges is that ion channels play crucial roles in landmark neurodevelopmental processes, including neuronal migration, neurite outgrowth, and synapse formation. Thus, pathogenic channel mutants can not only cause epileptic disorders by altering excitability, but further, by inducing morphological and synaptic abnormalities that are initiated during neocortex formation and may persist into the adult brain.
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Affiliation(s)
- Alessandro Bortolami
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, West Piscataway, NJ, USA
| | - Federico Sesti
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, West Piscataway, NJ, USA
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El Mouhi H, Abbassi M, Sayel H, Trhanint S, Natiq A, El Hejjioui B, Jalte M, Ahmadi Y, Chaouki S. Autosomal Dominant Intellectual Development Disorder-6 (MRD6) Without Seizures Linked to a De Novo Mutation in the grin2b Gene Revealed by Exome Sequencing: A Case Report of a Moroccan Child. Cureus 2023; 15:e46456. [PMID: 37927744 PMCID: PMC10623208 DOI: 10.7759/cureus.46456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2023] [Indexed: 11/07/2023] Open
Abstract
Autosomal dominant intellectual development disorder-6 (MRD6) arises from a grin2b gene mutation, inducing neurodevelopmental issues. The effects of MRD6 encompass cognitive disabilities, seizures, muscle tone decline, and autism-like traits. Its severity ranges from mild impairment to severe epilepsy. The disorder's rarity is emphasized by roughly 100 reported GRIN2B-related cases, spotlighting the gene's significance in brain development. We present the case of a three-year-old Moroccan boy who was referred to a neuropediatric department for a molecular diagnosis. Initial genetic testing yielded inconclusive results, and subsequent tests for Angelman syndrome and metabolic diseases showed no abnormalities. Given the complexity of the disorder, exome sequencing was employed to identify the underlying genetic cause. Exome sequencing identified a nonsense (STOP) mutation c.3912C>G (p.Tyr1304Ter) in the grin2b gene in the heterozygous state known to be present in MRD6 (Online Mendelian Inheritance in Man (OMIM) 613970). The family segregation study shows that this is a de novo variant, which is confirmed by Sanger sequencing. This variant has not been previously reported in the GnomAD database. Based on current scientific knowledge, the variant is considered pathogenic (PVS1, PS2, PM2, PP3, PP5) according to the criteria of the American College of Medical Genetics and Genomics (ACMG). The mutation in the grin2b gene (p.Tyr1304Ter) was predicted to be deleterious through bioinformatics analysis tools. This study highlights the crucial role of the grin2b gene in normal brain development and communication within the nervous system. It also sheds light on the impact of a novel genetic mutation, identified through exome sequencing, on causing an intellectual developmental disorder in a child patient from Morocco.
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Affiliation(s)
- Hinde El Mouhi
- Laboratory of Biomedical and Translational Research, Faculty of Medicine and Pharmacy and Dental Medicine, Sidi Mohamed Ben Abdellah University, Fez, MAR
- Center for Doctoral Studies Engineering Sciences and Techniques, Faculty of Sciences and Technologies, Sidi Mohammed Ben Abdellah University, Fez, MAR
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Meriame Abbassi
- Laboratory of Biomedical and Translational Research, Faculty of Medicine and Pharmacy and Dental Medicine, Sidi Mohamed Ben Abdellah University, Fez, MAR
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Hanane Sayel
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Said Trhanint
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Abdelhafid Natiq
- Department of Genetics, Faculty of Medicine and Pharmacy, Mohammed V University, Rabat, MAR
| | - Brahim El Hejjioui
- Laboratory of Biomedical and Translational Research, Faculty of Medicine and Pharmacy and Dental Medicine, Sidi Mohamed Ben Abdellah University, Fez, MAR
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Merym Jalte
- Laboratory of Biotechnology, Environment, Agri-food, and Health (LBEAH), Faculty of Sciences Dhar El Mahraz, Sidi Mohamed Ben Abdellah University, Fez, MAR
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Youssef Ahmadi
- Laboratory of Medical Genetics and Onco-genetics, Central Laboratory of Medical Analysis, Centre Hospitalier Universitaire (CHU) Hassan II, Fez, MAR
| | - Sana Chaouki
- Laboratory of Biomedical and Translational Research, Faculty of Medicine and Pharmacy and Dental Medicine, Sidi Mohamed Ben Abdellah University, Fez, MAR
- Department of Pediatrics, Centre Hospitalier Universitaire (CHU) Hassan II, FEZ, MAR
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11
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Zeibich R, Kwan P, J. O’Brien T, Perucca P, Ge Z, Anderson A. Applications for Deep Learning in Epilepsy Genetic Research. Int J Mol Sci 2023; 24:14645. [PMID: 37834093 PMCID: PMC10572791 DOI: 10.3390/ijms241914645] [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: 08/23/2023] [Revised: 09/11/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023] Open
Abstract
Epilepsy is a group of brain disorders characterised by an enduring predisposition to generate unprovoked seizures. Fuelled by advances in sequencing technologies and computational approaches, more than 900 genes have now been implicated in epilepsy. The development and optimisation of tools and methods for analysing the vast quantity of genomic data is a rapidly evolving area of research. Deep learning (DL) is a subset of machine learning (ML) that brings opportunity for novel investigative strategies that can be harnessed to gain new insights into the genomic risk of people with epilepsy. DL is being harnessed to address limitations in accuracy of long-read sequencing technologies, which improve on short-read methods. Tools that predict the functional consequence of genetic variation can represent breaking ground in addressing critical knowledge gaps, while methods that integrate independent but complimentary data enhance the predictive power of genetic data. We provide an overview of these DL tools and discuss how they may be applied to the analysis of genetic data for epilepsy research.
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Affiliation(s)
- Robert Zeibich
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC 3800, Australia; (R.Z.); (P.K.); (T.J.O.); (P.P.)
| | - Patrick Kwan
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC 3800, Australia; (R.Z.); (P.K.); (T.J.O.); (P.P.)
- Department of Neurology, Alfred Health, Melbourne, VIC 3004, Australia
- Department of Neurology, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC 3052, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Terence J. O’Brien
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC 3800, Australia; (R.Z.); (P.K.); (T.J.O.); (P.P.)
- Department of Neurology, Alfred Health, Melbourne, VIC 3004, Australia
- Department of Neurology, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC 3052, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Piero Perucca
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC 3800, Australia; (R.Z.); (P.K.); (T.J.O.); (P.P.)
- Department of Neurology, Alfred Health, Melbourne, VIC 3004, Australia
- Department of Neurology, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC 3052, Australia
- Epilepsy Research Centre, Department of Medicine, Austin Health, The University of Melbourne, Melbourne, VIC 3084, Australia
- Bladin-Berkovic Comprehensive Epilepsy Program, Department of Neurology, Austin Health, The University of Melbourne, Melbourne, VIC 3084, Australia
| | - Zongyuan Ge
- Faculty of Engineering, Monash University, Melbourne, VIC 3800, Australia;
- Monash-Airdoc Research, Monash University, Melbourne, VIC 3800, Australia
| | - Alison Anderson
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC 3800, Australia; (R.Z.); (P.K.); (T.J.O.); (P.P.)
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC 3052, Australia
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12
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Song R, Zhang J, Perszyk RE, Camp CR, Tang W, Kannan V, Li J, Xu Y, Chen J, Li Y, Liang SH, Traynelis SF, Yuan H. Differential responses of disease-related GRIN variants located in pore-forming M2 domain of N-methyl-D-aspartate receptor to FDA-approved inhibitors. J Neurochem 2023:10.1111/jnc.15942. [PMID: 37649269 PMCID: PMC10902181 DOI: 10.1111/jnc.15942] [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: 05/18/2023] [Revised: 07/22/2023] [Accepted: 07/27/2023] [Indexed: 09/01/2023]
Abstract
N-methyl-D-aspartate receptors (NMDAR), ionotropic glutamate receptors, mediate a slow component of excitatory synaptic transmission in the central nervous system and play a key role in normal brain function and development. Genetic variations in GRIN genes encoding NMDAR subunits that alter the receptor's functional characteristics are associated with a wide range of neurological and neuropsychiatric conditions. Pathological GRIN variants located in the M2 re-entrant loop lining the channel pore cause significant functional changes, the most consequential alteration being a reduction in voltage-dependent Mg2+ inhibition. Voltage-dependent Mg2+ block is a unique feature of NMDAR biology whereby channel activation requires both ligand binding and postsynaptic membrane depolarization. Thus, loss of NMDAR Mg2+ block will have a profound impact on synaptic function and plasticity. Here, we choose 11 missense variants within the GRIN1, GRIN2A, and GRIN2B genes that alter residues located in the M2 loop and significantly reduce Mg2+ inhibition. Each variant was evaluated for tolerance to genetic variation using the 3-dimensional structure and assessed for functional rescue pharmacology via electrophysiological recordings. Three FDA-approved NMDAR drugs-memantine, dextromethorphan, and ketamine-were chosen based on their ability to bind near the M2 re-entrant loop, potentially rectifying dysregulated NMDAR function by supplementing the reduced voltage-dependent Mg2+ block. These results provide insight of structural determinants of FDA-approved NMDAR drugs at their binding sites in the channel pore and may further define conditions necessary for the use of such agents as potential rescue pharmacology.
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Affiliation(s)
- Rui Song
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jin Zhang
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Riley E Perszyk
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Chad R Camp
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Weiting Tang
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Varun Kannan
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jia Li
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Yuchen Xu
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jiahui Chen
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Yinlong Li
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Steven H Liang
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Stephen F Traynelis
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
- Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, Georgia, USA
- Emory Neurodegenerative Disease Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Hongjie Yuan
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
- Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, Georgia, USA
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13
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Wang X, Mei D, Gou L, Zhao S, Gao C, Guo J, Luo S, Guo B, Yang Z, Wang Q, Tan T, Zhang Y. Functional Evaluation of a Novel GRIN2B Missense Variant Associated with Epilepsy and Intellectual Disability. Neuroscience 2023; 526:107-120. [PMID: 37385334 DOI: 10.1016/j.neuroscience.2023.06.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/17/2023] [Accepted: 06/21/2023] [Indexed: 07/01/2023]
Abstract
Epilepsy, a neurological condition, is widely prevalent among individuals with intellectual disability (ID). It is well established that N-methyl-D-aspartate (NMDA) receptors play an important role in both epilepsy and ID. Autosomal dominant mutations in the GRIN2B gene, which encodes the GluN2B subunit of the NMDA receptor, have been reported to be associated with epilepsy and ID. However, the underlying mechanism of this association is not well-understood. In this study, we identified a novel GRIN2B mutation (c.3272A > C, p.K1091T) in a patient with epilepsy and ID. The proband was a one year and ten months old girl. GRIN2B variant was inherited from her mother. We further investigated the functional consequences of this mutation. Our findings revealed that the p.K1091T mutation created a Casein kinase 2 phosphorylation site. Using recombinant NMDA receptors containing the GluN2B-K1091T along with GluN1 in HEK 293T cells, we observed significant defects in its interactions with postsynaptic density 95. It is accompanied by reduced delivery of the receptors to the cell membrane and a decrease in glutamate affinity. Moreover, primary neurons expressing GluN2B-K1091T also exhibited impaired surface expression of NMDA receptors, a reduction in dendritic spine number and excitatory synaptic transmission. In summary, our study reports a novel GRIN2B mutation and provides functional characteristics of this mutation in vitro, thereby contributing to the understanding of GRIN2B variants in epilepsy and ID.
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Affiliation(s)
- Xiaona Wang
- Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou Children's Hospital, Henan Provincial Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Engineering Research Center of Childhood Neurodevelopment, Zhengzhou 450018, Henan, China.
| | - Daoqi Mei
- Department of Neurology, Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou Children's Hospital, Zhengzhou 450018, Henan, China
| | - Lingshan Gou
- Center for Genetic Medicine, Xuzhou Maternity and Child Health Care Hospital Affiliated to Xuzhou Medical University, Xuzhou 221000, Jiangsu, China
| | - Shuai Zhao
- Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou Children's Hospital, Henan Provincial Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Engineering Research Center of Childhood Neurodevelopment, Zhengzhou 450018, Henan, China
| | - Chao Gao
- Department of Rehabilitation, Children's Hospital Affiliated to Zhengzhou University, Zhengzhou 450018, Henan, China
| | - Jisheng Guo
- School of Basic Medical Sciences, Yantai Campus of Binzhou Medical University, Yantai 264003, Shandong, China
| | - Shuying Luo
- Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou Children's Hospital, Henan Provincial Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Engineering Research Center of Childhood Neurodevelopment, Zhengzhou 450018, Henan, China
| | - Bin Guo
- School of Traditional Chinese Medicine, Ningxia Medical University, Ningxia 750004, China
| | - Zhigang Yang
- Department of Neurology, Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou Children's Hospital, Zhengzhou 450018, Henan, China
| | - Qi Wang
- Department of Histology and Embryology, School of Basic Medicine, Guizhou Medical University, Guiyang 550025, Guizhou, China.
| | - Tao Tan
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, Wenzhou Medical University, Wenzhou 325000, Zhejiang, China.
| | - Yaodong Zhang
- Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou Children's Hospital, Henan Provincial Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Engineering Research Center of Childhood Neurodevelopment, Zhengzhou 450018, Henan, China.
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14
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Mori T, Zhou M, Tabuchi K. Diverse Clinical Phenotypes of CASK-Related Disorders and Multiple Functional Domains of CASK Protein. Genes (Basel) 2023; 14:1656. [PMID: 37628707 PMCID: PMC10454856 DOI: 10.3390/genes14081656] [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: 08/07/2023] [Revised: 08/17/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023] Open
Abstract
CASK-related disorders are a form of rare X-linked neurological diseases and most of the patients are females. They are characterized by several symptoms, including microcephaly with pontine and cerebellar hypoplasia (MICPCH), epilepsy, congenital nystagmus, and neurodevelopmental disorders. Whole-genome sequencing has identified various mutations, including nonsense and missense mutations, from patients with CASK-related disorders, revealing correlations between specific mutations and clinical phenotypes. Notably, missense mutations associated with epilepsy and intellectual disability were found throughout the whole region of the CASK protein, while missense mutations related to microcephaly and MICPCH were restricted in certain domains. To investigate the pathophysiology of CASK-related disorders, research groups have employed diverse methods, including the generation of CASK knockout mice and the supplementation of CASK to rescue the phenotypes. These approaches have yielded valuable insights into the identification of functional domains of the CASK protein associated with a specific phenotype. Additionally, recent advancements in the AI-based prediction of protein structure, such as AlphaFold2, and the application of genome-editing techniques to generate CASK mutant mice carrying missense mutations from patients with CASK-related disorders, allow us to understand the pathophysiology of CASK-related disorders in more depth and to develop novel therapeutic methods for the fundamental treatment of CASK-related disorders.
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Affiliation(s)
- Takuma Mori
- Department of Neuroinnovation, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Matsumoto 390-8621, Japan;
- Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan;
| | - Mengyun Zhou
- Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan;
| | - Katsuhiko Tabuchi
- Department of Neuroinnovation, Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Matsumoto 390-8621, Japan;
- Department of Molecular and Cellular Physiology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan;
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15
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Hussein Y, Tripathi U, Choudhary A, Nayak R, Peles D, Rosh I, Rabinski T, Djamus J, Vatine GD, Spiegel R, Garin-Shkolnik T, Stern S. Early maturation and hyperexcitability is a shared phenotype of cortical neurons derived from different ASD-associated mutations. Transl Psychiatry 2023; 13:246. [PMID: 37414777 DOI: 10.1038/s41398-023-02535-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 07/08/2023] Open
Abstract
Autism Spectrum Disorder (ASD) is characterized mainly by social and sensory-motor abnormal and repetitive behavior patterns. Over hundreds of genes and thousands of genetic variants were reported to be highly penetrant and causative of ASD. Many of these mutations cause comorbidities such as epilepsy and intellectual disabilities (ID). In this study, we measured cortical neurons derived from induced pluripotent stem cells (iPSCs) of patients with four mutations in the genes GRIN2B, SHANK3, UBTF, as well as chromosomal duplication in the 7q11.23 region and compared them to neurons derived from a first-degree relative without the mutation. Using a whole-cell patch-clamp, we observed that the mutant cortical neurons demonstrated hyperexcitability and early maturation compared to control lines. These changes were characterized by increased sodium currents, increased amplitude and rate of excitatory postsynaptic currents (EPSCs), and more evoked action potentials in response to current stimulation in early-stage cell development (3-5 weeks post differentiation). These changes that appeared in all the different mutant lines, together with previously reported data, indicate that an early maturation and hyperexcitability may be a convergent phenotype of ASD cortical neurons.
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Affiliation(s)
- Yara Hussein
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Utkarsh Tripathi
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Ashwani Choudhary
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Ritu Nayak
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - David Peles
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Idan Rosh
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Tatiana Rabinski
- The Department of Physiology and Cell Biology, Faculty of Health Sciences and the Regenerative Medicine and Stem Cell (RMSC) Research Center, Ben-Gurion University of the Negev, Beer Sheva, Israel
- The Regenerative Medicine and Stem Cell (RMSC) Research Center, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Jose Djamus
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Gad David Vatine
- The Department of Physiology and Cell Biology, Faculty of Health Sciences and the Regenerative Medicine and Stem Cell (RMSC) Research Center, Ben-Gurion University of the Negev, Beer Sheva, Israel
- The Regenerative Medicine and Stem Cell (RMSC) Research Center, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Ronen Spiegel
- Center for Rare Diseases, Emek Medical Center, Afula, Israel
| | | | - Shani Stern
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
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16
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The Role of Glutamate Receptors in Epilepsy. Biomedicines 2023; 11:biomedicines11030783. [PMID: 36979762 PMCID: PMC10045847 DOI: 10.3390/biomedicines11030783] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/26/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Glutamate is an essential excitatory neurotransmitter in the central nervous system, playing an indispensable role in neuronal development and memory formation. The dysregulation of glutamate receptors and the glutamatergic system is involved in numerous neurological and psychiatric disorders, especially epilepsy. There are two main classes of glutamate receptor, namely ionotropic and metabotropic (mGluRs) receptors. The former stimulate fast excitatory neurotransmission, are N-methyl-d-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), and kainate; while the latter are G-protein-coupled receptors that mediate glutamatergic activity via intracellular messenger systems. Glutamate, glutamate receptors, and regulation of astrocytes are significantly involved in the pathogenesis of acute seizure and chronic epilepsy. Some glutamate receptor antagonists have been shown to be effective for the treatment of epilepsy, and research and clinical trials are ongoing.
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17
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den Hollander B, Veenvliet ARJ, Rothuizen-Lindenschot M, van Essen P, Peters G, Santos-Gómez A, Olivella M, Altafaj X, Brands MM, Jacobs BAW, van Karnebeek CD. Evidence for effect of l-serine, a novel therapy for GRIN2B-related neurodevelopmental disorder. Mol Genet Metab 2023; 138:107523. [PMID: 36758276 DOI: 10.1016/j.ymgme.2023.107523] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 01/19/2023] [Accepted: 01/19/2023] [Indexed: 01/22/2023]
Abstract
RATIONALE To date, causal therapy is potentially available for GRIN2B-related neurodevelopmental disorder (NDD) due to loss-of-function (LoF) variants in GRIN2B, resulting in dysfunction of the GluN2B subunit-containing N-methyl-d-aspartate receptor (NMDAR). Recently, in vitro experiments showed that high doses of NMDAR co-agonist d-serine has the potential to boost the activity in GluN2B LoF variant-containing NMDARs. Initial reports of GRIN2B-NDD patients LoF variants, treated with l-serine using different regimens, showed varying effects on motor and cognitive performance, communication, behavior and EEG. Here, this novel treatment using a standardized protocol with an innovative developmental outcome measure is explored further in an open-label observational GRIN2B-NDD study. METHODS Initially, in vitro studies were conducted in order to functionally stratify two de novo GRIN2B variants present in two female patients (18 months and 4 years old). Functional studies showed that both variants are LoF, and thus the patients were treated experimentally according to an approved protocol with oral l-serine (500 mg/kg/day in 4 doses) for a period of 12 months. Both patients showed a heterogeneous clinical phenotype, however overlapping symptoms were present: intellectual developmental disability (IDD), behavioral abnormalities and hypotonia. Outcome measures included laboratory tests, quality of life, sleep, irritability, stool, and performance skills, measured by, among others, the Perceive-Recall-Plan-Perform System of Task Analysis (PRPP-Assessment). RESULTS Both patients tolerated l-serine without adverse effects. In one patient, improvement in psychomotor development and cognitive functioning was observed after 12 months (PRPP mastery score 10% at baseline, 78% at twelve months). In the most severe clinically affected patient no significant objective improvement in validated outcomes was observed. Caregivers of both patients reported subjective increase of alertness and improved communication skills. CONCLUSION Our observational study confirms that l-serine supplementation is safe in patients with GRIN2B-NDD associated with LoF variants, and may accelerate psychomotor development and ameliorate cognitive performance in some but not all patients. The PRPP-Assessment, a promising instrument to evaluate everyday activities and enhance personalized and value-based care, was not performed in the severely affected patient, meaning that possible positive results may have been missed. To generate stronger evidence for effect of l-serine in GRIN2B-NDD, we will perform placebo-controlled n-of-1 trials.
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Affiliation(s)
- B den Hollander
- Amsterdam University Medical Centers, University of Amsterdam, Department of Pediatrics, Emma Children's Hospital, Amsterdam Gastroenterology Endocrinology Metabolism, Meibergdreef 9, Amsterdam, The Netherlands; Amsterdam UMC, Emma Center for Personalized Medicine, Amsterdam, The Netherlands; United for Metabolic Diseases, The Netherlands
| | - A R J Veenvliet
- Amsterdam University Medical Centers, University of Amsterdam, Department of Pediatrics, Emma Children's Hospital, Amsterdam Gastroenterology Endocrinology Metabolism, Meibergdreef 9, Amsterdam, The Netherlands; Amsterdam UMC, Emma Center for Personalized Medicine, Amsterdam, The Netherlands; United for Metabolic Diseases, The Netherlands; Radboud University Medical Center, Department of Pediatrics, Amalia Children's Hospital, Geert Grooteplein Zuid 10, Nijmegen, The Netherlands
| | - M Rothuizen-Lindenschot
- Radboud University Medical Center, Department of Rehabilitation Medicine, Geert Grooteplein Zuid 10, Nijmegen, The Netherlands; HAN University of Applied Sciences, Department of Occupational Therapy, Kapittelweg 33, Nijmegen, The Netherlands
| | - P van Essen
- Radboud University Medical Center, Department of Pediatrics, Amalia Children's Hospital, Geert Grooteplein Zuid 10, Nijmegen, The Netherlands
| | - G Peters
- Radboud University Medical Center, Department of Rehabilitation Medicine, Geert Grooteplein Zuid 10, Nijmegen, The Netherlands
| | - A Santos-Gómez
- Neurophysiology Laboratory, Department of Biomedicine, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain; August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain
| | - M Olivella
- Biosciences Department, Faculty of Sciences and Technology, University of Vic-Central University of Catalonia, Barcelona, Spain
| | - X Altafaj
- Neurophysiology Laboratory, Department of Biomedicine, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain; August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain
| | - M M Brands
- Amsterdam University Medical Centers, University of Amsterdam, Department of Pediatrics, Emma Children's Hospital, Amsterdam Gastroenterology Endocrinology Metabolism, Meibergdreef 9, Amsterdam, The Netherlands; Amsterdam UMC, Emma Center for Personalized Medicine, Amsterdam, The Netherlands; United for Metabolic Diseases, The Netherlands
| | - B A W Jacobs
- Amsterdam University Medical Centers, Department of Pharmacy and Clinical Pharmacology, Meibergdreef 9, Amsterdam, The Netherlands; Medicine for Society, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - C D van Karnebeek
- Amsterdam University Medical Centers, University of Amsterdam, Department of Pediatrics, Emma Children's Hospital, Amsterdam Gastroenterology Endocrinology Metabolism, Meibergdreef 9, Amsterdam, The Netherlands; Amsterdam UMC, Emma Center for Personalized Medicine, Amsterdam, The Netherlands; United for Metabolic Diseases, The Netherlands; Amsterdam University Medical Centers, Department of Human Genetics, Amsterdam Reproduction and Development, Meibergdreef 9, Amsterdam, The Netherlands.
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18
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Brock S, Laquerriere A, Marguet F, Myers SJ, Hongjie Y, Baralle D, Vanderhasselt T, Stouffs K, Keymolen K, Kim S, Allen J, Shaulsky G, Chelly J, Marcorelle P, Aziza J, Villard L, Sacaze E, de Wit MCY, Wilke M, Mancini GMS, Hehr U, Lim D, Mansour S, Traynelis SF, Beneteau C, Denis-Musquer M, Jansen AC, Fry AE, Bahi-Buisson N. Overlapping cortical malformations in patients with pathogenic variants in GRIN1 and GRIN2B. J Med Genet 2023; 60:183-192. [PMID: 35393335 PMCID: PMC10642159 DOI: 10.1136/jmedgenet-2021-107971] [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: 05/13/2021] [Accepted: 03/16/2022] [Indexed: 01/29/2023]
Abstract
BACKGROUND Malformations of cortical development (MCDs) have been reported in a subset of patients with pathogenic heterozygous variants in GRIN1 or GRIN2B, genes which encode for subunits of the N-methyl-D-aspartate receptor (NMDAR). The aim of this study was to further define the phenotypic spectrum of NMDAR-related MCDs. METHODS We report the clinical, radiological and molecular features of 7 new patients and review data on 18 previously reported individuals with NMDAR-related MCDs. Neuropathological findings for two individuals with heterozygous variants in GRIN1 are presented. We report the clinical and neuropathological features of one additional individual with homozygous pathogenic variants in GRIN1. RESULTS Heterozygous variants in GRIN1 and GRIN2B were associated with overlapping severe clinical and imaging features, including global developmental delay, epilepsy, diffuse dysgyria, dysmorphic basal ganglia and hippocampi. Neuropathological examination in two fetuses with heterozygous GRIN1 variants suggests that proliferation as well as radial and tangential neuronal migration are impaired. In addition, we show that neuronal migration is also impaired by homozygous GRIN1 variants in an individual with microcephaly with simplified gyral pattern. CONCLUSION These findings expand our understanding of the clinical and imaging features of the 'NMDARopathy' spectrum and contribute to our understanding of the likely underlying pathogenic mechanisms leading to MCD in these patients.
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Affiliation(s)
- Stefanie Brock
- Department of Pathology, Universitair Ziekenhuis Brussel, Brussels, Belgium
- Neurogenetics Research Group, Reproduction Genetics and Regenerative Medicine Research Cluster, Vrije Universiteit Brussel, Brussels, Belgium
| | - Annie Laquerriere
- Normandy Centre for Genomic and Personalized Medicine, INSERM U1245, Rouen, France
- Department of Pathology, Rouen University Hospital, Rouen, France
| | - Florent Marguet
- Normandy Centre for Genomic and Personalized Medicine, INSERM U1245, Rouen, France
- Department of Pathology, Rouen University Hospital, Rouen, France
| | - Scott J Myers
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
- Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
| | - Yuan Hongjie
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
- Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
| | - Diana Baralle
- Human Development and Health, University of Southampton, Southampton, UK
| | - Tim Vanderhasselt
- Department of Radiology, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
| | - Katrien Stouffs
- Neurogenetics Research Group, Reproduction Genetics and Regenerative Medicine Research Cluster, Vrije Universiteit Brussel, Brussels, Belgium
- Center for Reproduction and Genetics, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
| | - Kathelijn Keymolen
- Center for Reproduction and Genetics, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium
| | - Sukhan Kim
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
- Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
| | - James Allen
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
- Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
| | - Gil Shaulsky
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
- Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
| | - Jamel Chelly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR 7104, INSERM U1258, Université de Strasbourg, Strasbourg, France
- Laboratoire de Diagnostic Génétique, Hôpitaux Universitaire de Strasbourg, Strasbourg, France
| | - Pascale Marcorelle
- Service d'Anatomie Pathologique, Centre Hospitalier Universitaire de Brest; Laboratoire Neurosciences de Brest, Université de Brest, Brest, France
| | - Jacqueline Aziza
- Department of Pathology, University Institute for Cancer, Toulouse, France
| | - Laurent Villard
- Inserm, Marseille Medical Genetics Center, Aix-Marseille University, Marseille, France
- Department of Medical Genetics, La Timone Children's Hospital, Marseille, France
| | - Elise Sacaze
- Department of Pediatrics, Centre Hospitalier Universitaire de Brest, Brest, France
| | - Marie C Y de Wit
- Department of Pediatric Neurology, ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Martina Wilke
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Ute Hehr
- Center for Human Genetics, Universitätsklinikum Regensburg, Regensburg, Germany
| | - Derek Lim
- West Midlands Regional Genetics Service and Birmingham Health Partners, Birmingham Women's and Children's Hospitals NHS Foundation Trust, University of Southampton, Southampton, UK
| | - Sahar Mansour
- SW Thames Regional Genetics Service, University of London St George's Molecular and Clinical Sciences Research Institute, London, UK
| | - Stephen F Traynelis
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
- Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine Atlanta, Atlanta, Georgia, USA
| | - Claire Beneteau
- Département de Génétique, Hôpital Universitaire de Nantes, Nantes, France
- UF de Fœtopathologie et Génétique, CHU Nantes, Nantes, France
| | - Marie Denis-Musquer
- UF de Fœtopathologie et Génétique, CHU Nantes, Nantes, France
- Department of Pathology, CHU Nantes, Nantes, France
| | - Anna C Jansen
- Pediatric Neurology Unit, Universitair Ziekenhuis Antwerpen, Antwerp, Belgium
| | - Andrew E Fry
- Institute of Medical Genetics, University Hospital of Wales, Cardiff, UK
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, UK
| | - Nadia Bahi-Buisson
- Pediatric Neurology, Necker Enfants Malades Hospital, Université de Paris, Paris, France
- Embryology and Genetics of Congenital Malformations, Institut Imagine (INSERM UMR-1163), Paris, France
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19
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Sabo SL, Lahr JM, Offer M, Weekes ALA, Sceniak MP. GRIN2B-related neurodevelopmental disorder: current understanding of pathophysiological mechanisms. Front Synaptic Neurosci 2023; 14:1090865. [PMID: 36704660 PMCID: PMC9873235 DOI: 10.3389/fnsyn.2022.1090865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023] Open
Abstract
The GRIN2B-related neurodevelopmental disorder is a rare disease caused by mutations in the GRIN2B gene, which encodes the GluN2B subunit of NMDA receptors. Most individuals with GRIN2B-related neurodevelopmental disorder present with intellectual disability and developmental delay. Motor impairments, autism spectrum disorder, and epilepsy are also common. A large number of pathogenic de novo mutations have been identified in GRIN2B. However, it is not yet known how these variants lead to the clinical symptoms of the disease. Recent research has begun to address this issue. Here, we describe key experimental approaches that have been used to better understand the pathophysiology of this disease. We discuss the impact of several distinct pathogenic GRIN2B variants on NMDA receptor properties. We then critically review pivotal studies examining the synaptic and neurodevelopmental phenotypes observed when disease-associated GluN2B variants are expressed in neurons. These data provide compelling evidence that various GluN2B mutants interfere with neuronal differentiation, dendrite morphogenesis, synaptogenesis, and synaptic plasticity. Finally, we identify important open questions and considerations for future studies aimed at understanding this complex disease. Together, the existing data provide insight into the pathophysiological mechanisms that underlie GRIN2B-related neurodevelopmental disorder and emphasize the importance of comparing the effects of individual, disease-associated variants. Understanding the molecular, cellular and circuit phenotypes produced by a wide range of GRIN2B variants should lead to the identification of core neurodevelopmental phenotypes that characterize the disease and lead to its symptoms. This information could help guide the development and application of effective therapeutic strategies for treating individuals with GRIN2B-related neurodevelopmental disorder.
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Affiliation(s)
- Shasta L. Sabo
- Department of Biology, Central Michigan University, Mount Pleasant, MI, United States,Program in Biochemistry, Cell and Molecular Biology, Central Michigan University, Mount Pleasant, MI, United States,Program in Neuroscience, Central Michigan University, Mount Pleasant, MI, United States,*Correspondence: Shasta L. Sabo
| | - Jessica M. Lahr
- Program in Biochemistry, Cell and Molecular Biology, Central Michigan University, Mount Pleasant, MI, United States
| | - Madelyn Offer
- Program in Neuroscience, Central Michigan University, Mount Pleasant, MI, United States
| | - Anika LA Weekes
- Program in Biochemistry, Cell and Molecular Biology, Central Michigan University, Mount Pleasant, MI, United States
| | - Michael P. Sceniak
- Department of Biology, Central Michigan University, Mount Pleasant, MI, United States
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20
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Santos-Gómez A, García-Recio A, Miguez-Cabello F, Soto D, Altafaj X, Olivella M. Identification of homologous GluN subunits variants accelerates GRIN variants stratification. Front Cell Neurosci 2022; 16:998719. [PMID: 36619673 PMCID: PMC9816381 DOI: 10.3389/fncel.2022.998719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 12/01/2022] [Indexed: 12/24/2022] Open
Abstract
The clinical spectrum of GRIN-related neurodevelopmental disorders (GRD) results from gene- and variant-dependent primary alterations of the NMDA receptor, disturbing glutamatergic neurotransmission. Despite GRIN gene variants' functional annotations being dually critical for stratification and precision medicine design, genetically diagnosed pathogenic GRIN variants currently outnumber their relative functional annotations. Based on high-resolution crystal 3D models and topological domains conservation between GluN1, GluN2A, and GluN2B subunits of the NMDAR, we have generated GluN1-GluN2A-GluN2B subunits structural superimposition model to find equivalent positions between GluN subunits. We have developed a GRIN structural algorithm that predicts functional changes in the equivalent structural positions in other GluN subunits. GRIN structural algorithm was computationally evaluated to the full GRIN missense variants repertoire, consisting of 4,525 variants. The analysis of this structure-based model revealed an absolute predictive power for GluN1, GluN2A, and GluN2B subunits, both in terms of pathogenicity-association (benign vs. pathogenic variants) and functional impact (loss-of-function, benign, gain-of-function). Further, we validated this computational algorithm experimentally, using an in silico library of GluN2B-equivalent GluN2A artificial variants, designed from pathogenic GluN2B variants. Thus, the implementation of the GRIN structural algorithm allows to computationally predict the pathogenicity and functional annotations of GRIN variants, resulting in the duplication of pathogenic GRIN variants assignment, reduction by 30% of GRIN variants with uncertain significance, and increase by 70% of functionally annotated GRIN variants. Finally, GRIN structural algorithm has been implemented into GRIN variants Database (http://lmc.uab.es/grindb), providing a computational tool that accelerates GRIN missense variants stratification, contributing to clinical therapeutic decisions for this neurodevelopmental disorder.
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Affiliation(s)
- Ana Santos-Gómez
- Neurophysiology Laboratory, Department of Biomedicine, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain
| | - Adrián García-Recio
- Bioinfomatics and Medical Statistics Group, University of Vic—Central University of Catalonia, Barcelona, Spain
| | - Federico Miguez-Cabello
- Neurophysiology Laboratory, Department of Biomedicine, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain
| | - David Soto
- Neurophysiology Laboratory, Department of Biomedicine, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain
| | - Xavier Altafaj
- Neurophysiology Laboratory, Department of Biomedicine, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain,*Correspondence: Xavier Altafaj Mireia Olivella
| | - Mireia Olivella
- Bioinfomatics and Medical Statistics Group, University of Vic—Central University of Catalonia, Barcelona, Spain,*Correspondence: Xavier Altafaj Mireia Olivella
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21
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Siddique R, Awan FM, Nabi G, Khan S, Xue M. Chronic jet lag-like conditions dysregulate molecular profiles of neurological disorders in nucleus accumbens and prefrontal cortex. Front Neuroinform 2022; 16:1031448. [PMID: 36582489 PMCID: PMC9792783 DOI: 10.3389/fninf.2022.1031448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/22/2022] [Indexed: 12/14/2022] Open
Abstract
Background Patients with neurological disorders often display altered circadian rhythms. The disrupted circadian rhythms through chronic jetlag or shiftwork are thought to increase the risk and severity of human disease including, cancer, psychiatric, and related brain diseases. Results In this study, we investigated the impact of shiftwork or chronic jetlag (CJL) like conditions on mice's brain. Transcriptome profiling based on RNA sequencing revealed that genes associated with serious neurological disorders were differentially expressed in the nucleus accumbens (NAc) and prefrontal cortex (PFC). According to the quantitative PCR (qPCR) analysis, several key regulatory genes associated with neurological disorders were significantly altered in the NAc, PFC, hypothalamus, hippocampus, and striatum. Serotonin levels and the expression levels of serotonin transporters and receptors were significantly altered in mice treated with CJL. Conclusion Overall, these results indicate that CJL may increase the risk of neurological disorders by disrupting the key regulatory genes, biological functions, serotonin, and corticosterone. These molecular linkages can further be studied to investigate the mechanism underlying CJL or shiftwork-mediated neurological disorders in order to develop treatment strategies.
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Affiliation(s)
- Rabeea Siddique
- Department of Cerebrovascular Diseases, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Henan Medical Key Laboratory of Translational Cerebrovascular Diseases, Zhengzhou, Henan, China
| | - Faryal Mehwish Awan
- Department of Medical Lab Technology, The University of Haripur, Haripur, Pakistan
| | - Ghulam Nabi
- Institute of Nature Conservation, Polish Academy of Sciences, Kraków, Poland
| | - Suliman Khan
- Department of Cerebrovascular Diseases, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Henan Medical Key Laboratory of Translational Cerebrovascular Diseases, Zhengzhou, Henan, China,Department of Medical Lab Technology, The University of Haripur, Haripur, Pakistan,*Correspondence: Suliman Khan, ;
| | - Mengzhou Xue
- Department of Cerebrovascular Diseases, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Henan Medical Key Laboratory of Translational Cerebrovascular Diseases, Zhengzhou, Henan, China,Mengzhou Xue,
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22
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Haddow K, Kind PC, Hardingham GE. NMDA Receptor C-Terminal Domain Signalling in Development, Maturity, and Disease. Int J Mol Sci 2022; 23:ijms231911392. [PMID: 36232696 PMCID: PMC9570437 DOI: 10.3390/ijms231911392] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 11/18/2022] Open
Abstract
The NMDA receptor is a Ca2+-permeant glutamate receptor which plays key roles in health and disease. Canonical NMDARs contain two GluN2 subunits, of which 2A and 2B are predominant in the forebrain. Moreover, the relative contribution of 2A vs. 2B is controlled both developmentally and in an activity-dependent manner. The GluN2 subtype influences the biophysical properties of the receptor through difference in their N-terminal extracellular domain and transmembrane regions, but they also have large cytoplasmic Carboxyl (C)-terminal domains (CTDs) which have diverged substantially during evolution. While the CTD identity does not influence NMDAR subunit specific channel properties, it determines the nature of CTD-associated signalling molecules and has been implicated in mediating the control of subunit composition (2A vs. 2B) at the synapse. Historically, much of the research into the differential function of GluN2 CTDs has been conducted in vitro by over-expressing mutant subunits, but more recently, the generation of knock-in (KI) mouse models have allowed CTD function to be probed in vivo and in ex vivo systems without heterologous expression of GluN2 mutants. In some instances, findings involving KI mice have been in disagreement with models that were proposed based on earlier approaches. This review will examine the current research with the aim of addressing these controversies and how methodology may contribute to differences between studies. We will also discuss the outstanding questions regarding the role of GluN2 CTD sequences in regulating NMDAR subunit composition, as well as their relevance to neurodegenerative disease and neurodevelopmental disorders.
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Affiliation(s)
- Kirsty Haddow
- UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Chancellor’s Building, Edinburgh EH16 4SB, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Peter C. Kind
- UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Chancellor’s Building, Edinburgh EH16 4SB, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Giles E. Hardingham
- UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Chancellor’s Building, Edinburgh EH16 4SB, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
- Correspondence:
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23
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Chidambaram S, Manokaran RK. Favorable Response to "Memantine" in a Child with GRIN2B Epileptic Encephalopathy. Neuropediatrics 2022; 53:287-290. [PMID: 34844267 DOI: 10.1055/s-0041-1739130] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
GRIN2B is a gene encoding GluN2B subunit under the family of N-methyl D-aspartate (NMDA) receptors, which is responsible for neurogenesis and cognitive processes. The role of NMDA receptor antagonists like memantine is being explored for therapies in drug-resistant epilepsies. Here, we present a case of a 20-month-old boy who presented with refractory epileptic spasms. Upon failure of multiple antiepileptic drugs, he was started on oral memantine. There was a significant reduction in average seizure episodes by ∼80%. The use of memantine along with antiepileptic drug polytherapy has proved to be beneficial in our case. Our experience with memantine and favorable outcome opens up the scope of more research into the use of NMDA receptor antagonist as a drug option for refractory epilepsies with proven genetic mutation and hence improves the overall neurodevelopmental outcome and survival chance.
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Affiliation(s)
- Sathya Chidambaram
- Department of Paediatrics, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu
| | - Ranjith Kumar Manokaran
- Division of Paediatric Neurology, Department of Neurology, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu
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24
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Shah AA, Amjad M, Hassan JU, Ullah A, Mahmood A, Deng H, Ali Y, Gul F, Xia K. Molecular Insights into the Role of Pathogenic nsSNPs in GRIN2B Gene Provoking Neurodevelopmental Disorders. Genes (Basel) 2022; 13:genes13081332. [PMID: 35893069 PMCID: PMC9394290 DOI: 10.3390/genes13081332] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/11/2022] [Accepted: 07/20/2022] [Indexed: 12/04/2022] Open
Abstract
The GluN2B subunit of N-methyl-D-aspartate receptors plays an important role in the physiology of different neurodevelopmental diseases. Genetic variations in the GluN2B coding gene (GRIN2B) have consistently been linked to West syndrome, intellectual impairment with focal epilepsy, developmental delay, macrocephaly, corticogenesis, brain plasticity, as well as infantile spasms and Lennox–Gastaut syndrome. It is unknown, however, how GRIN2B genetic variation impacts protein function. We determined the cumulative pathogenic impact of GRIN2B variations on healthy participants using a computational approach. We looked at all of the known mutations and calculated the impact of single nucleotide polymorphisms on GRIN2B, which encodes the GluN2B protein. The pathogenic effect, functional impact, conservation analysis, post-translation alterations, their driving residues, and dynamic behaviors of deleterious nsSNPs on protein models were then examined. Four polymorphisms were identified as phylogenetically conserved PTM drivers and were related to structural and functional impact: rs869312669 (p.Thr685Pro), rs387906636 (p.Arg682Cys), rs672601377 (p.Asn615Ile), and rs1131691702 (p.Ser526Pro). The combined impact of protein function is accounted for by the calculated stability, compactness, and total globularity score. GluN2B hydrogen occupancy was positively associated with protein stability, and solvent-accessible surface area was positively related to globularity. Furthermore, there was a link between GluN2B protein folding, movement, and function, indicating that both putative high and low local movements were linked to protein function. Multiple GRIN2B genetic variations are linked to gene expression, phylogenetic conservation, PTMs, and protein instability behavior in neurodevelopmental diseases. These findings suggest the relevance of GRIN2B genetic variations in neurodevelopmental problems.
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Affiliation(s)
- Abid Ali Shah
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha 410013, China; (A.A.S.); (A.M.)
| | - Marryam Amjad
- District Headquarter (DHQ) Hospital, Faisalabad 38000, Punjab, Pakistan;
| | | | - Asmat Ullah
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark;
| | - Arif Mahmood
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha 410013, China; (A.A.S.); (A.M.)
| | - Huiyin Deng
- Department of Anesthesiology, The Third Xiangya Hospital of Central South University, Changsha 410013, China;
| | - Yasir Ali
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad 45320, Pakistan; (Y.A.); (F.G.)
| | - Fouzia Gul
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad 45320, Pakistan; (Y.A.); (F.G.)
| | - Kun Xia
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha 410013, China; (A.A.S.); (A.M.)
- Hengyang Medical School, University of South China, Hengyang 421000, China
- CAS Center for Excellence in Brain Science and Intelligences Technology (CEBSIT), Chinese Academy of Sciences, Shanghai 200030, China
- Correspondence: ; Tel.: +86-731-8480-5357
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25
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Benske TM, Mu TW, Wang YJ. Protein quality control of N-methyl-D-aspartate receptors. Front Cell Neurosci 2022; 16:907560. [PMID: 35936491 PMCID: PMC9352929 DOI: 10.3389/fncel.2022.907560] [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: 03/29/2022] [Accepted: 06/29/2022] [Indexed: 12/23/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs) are glutamate-gated cation channels that mediate excitatory neurotransmission and are critical for synaptic development and plasticity in the mammalian central nervous system (CNS). Functional NMDARs typically form via the heterotetrameric assembly of GluN1 and GluN2 subunits. Variants within GRIN genes are implicated in various neurodevelopmental and neuropsychiatric disorders. Due to the significance of NMDAR subunit composition for regional and developmental signaling at synapses, properly folded receptors must reach the plasma membrane for their function. This review focuses on the protein quality control of NMDARs. Specifically, we review the quality control mechanisms that ensure receptors are correctly folded and assembled within the endoplasmic reticulum (ER) and trafficked to the plasma membrane. Further, we discuss disease-associated variants that have shown disrupted NMDAR surface expression and function. Finally, we discuss potential targeted pharmacological and therapeutic approaches to ameliorate disease phenotypes by enhancing the expression and surface trafficking of subunits harboring disease-associated variants, thereby increasing their incorporation into functional receptors.
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Affiliation(s)
| | - Ting-Wei Mu
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Ya-Juan Wang
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
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26
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An Epilepsy-Associated Mutation of Salt-Inducible Kinase 1 Increases the Susceptibility to Epileptic Seizures and Interferes with Adrenocorticotropic Hormone Therapy for Infantile Spasms in Mice. Int J Mol Sci 2022; 23:ijms23147927. [PMID: 35887274 PMCID: PMC9319016 DOI: 10.3390/ijms23147927] [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: 06/24/2022] [Revised: 07/14/2022] [Accepted: 07/16/2022] [Indexed: 12/10/2022] Open
Abstract
Six mutations in the salt-inducible kinase 1 (SIK1) have been identified in developmental and epileptic encephalopathy (DEE-30) patients, and two of the mutations are nonsense mutations that truncate the C-terminal region of SIK1. In a previous study, we generated SIK1 mutant (SIK1-MT) mice recapitulating the C-terminal truncated mutations using CRISPR/Cas9-mediated genome editing and found an increase in excitatory synaptic transmission and enhancement of neural excitability in neocortical neurons in SIK1-MT mice. NMDA was injected into SIK1-MT males to induce epileptic seizures in the mice. The severity of the NMDA-induced seizures was estimated by the latency and the number of tail flickering and hyperflexion. Activated brain regions were evaluated by immunohistochemistry against c-fos, Iba1, and GFAP. As another epilepsy model, pentylenetetrazol was injected into the adult SIK1 mutant mice. Seizure susceptibility induced by both NMDA and PTZ was enhanced in SIK1-MT mice. Brain regions including the thalamus and hypothalamus were strongly activated in NMDA-induced seizures. The epilepsy-associated mutation of SIK1 canceled the pharmacological effects of the ACTH treatment on NMDA-induced seizures. These results suggest that SIK1 may be involved in the neuropathological mechanisms of NMDA-induced spasms and the pharmacological mechanism of ACTH treatment.
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Menteş M, Karakuzulu BB, Uçar GB, Yandım C. Comparative molecular dynamics analyses on PIK3CA hotspot mutations with PI3Kα specific inhibitors and ATP. Comput Biol Chem 2022; 99:107726. [PMID: 35842959 DOI: 10.1016/j.compbiolchem.2022.107726] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/19/2022] [Accepted: 07/06/2022] [Indexed: 11/03/2022]
Abstract
PI3K pathway is heavily emphasized in cancer where PIK3CA, which encodes for the p110α subunit of PI3Kα, presents itself as the second most common mutated gene. A lot of effort has been put in developing PI3K inhibitors, opening promising avenues for the treatment of cancer. Among these, PI3Kα specific inhibitor alpelisib was approved by FDA for breast cancer and other α-isoform specific inhibitors such as inavolisib and serabelisib reached clinical trials. However, the mode of action of these inhibitors on mutated PI3Kα and how they interact with mutant structures has not been fully elucidated yet. In this study, we are revealing the calculated interactions and binding affinities of these inhibitors within the context of PIK3CA hotspot mutations (E542K, E545K and H1047R) by employing molecular dynamics (MD) simulations. We performed principal component analysis to understand the motions of the protein complex during our simulations and also checked the correlated motions of all amino acids. Binding affinity calculations with MM-PBSA confirmed the consistent binding of alpelisib across mutations and revealed relatively higher affinities for inavolisib towards wild-type and H1047R mutant structures in comparison to other inhibitors. On the other hand, E542K mutation significantly impaired the interaction of inavolisib and serabelisib with PI3Kα. We also investigated the structural relationship of the natural ligand ATP with PI3Kα, and interestingly realized a significant reduction in binding affinity for the mutants, with potentially unexpected implications on the mechanisms that render these mutations oncogenic. Moreover, correlated motions of all residues were generally higher for ATP except the H1047R mutation which exhibited a distinguishable reduction. The results presented here could be guiding for pre-clinical and clinical studies of personalized medicine where individual mutations are a strong consideration point.
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Affiliation(s)
- Muratcan Menteş
- Izmir University of Economics, Faculty of Engineering, Department of Genetics and Bioengineering, 35330 Balçova, İzmir, Turkey
| | - Başak Buse Karakuzulu
- Izmir University of Economics, Faculty of Engineering, Department of Genetics and Bioengineering, 35330 Balçova, İzmir, Turkey
| | - Gönlüm Bahar Uçar
- Izmir University of Economics, Faculty of Engineering, Department of Genetics and Bioengineering, 35330 Balçova, İzmir, Turkey
| | - Cihangir Yandım
- Izmir University of Economics, Faculty of Engineering, Department of Genetics and Bioengineering, 35330 Balçova, İzmir, Turkey; Izmir Biomedicine and Genome Center (IBG), Dokuz Eylül University Health Campus, 35340 İnciraltı, İzmir, Turkey.
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Synaptic Dysfunction by Mutations in GRIN2B: Influence of Triheteromeric NMDA Receptors on Gain-of-Function and Loss-of-Function Mutant Classification. Brain Sci 2022; 12:brainsci12060789. [PMID: 35741674 PMCID: PMC9221112 DOI: 10.3390/brainsci12060789] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/11/2022] [Accepted: 06/12/2022] [Indexed: 02/01/2023] Open
Abstract
GRIN2B mutations are rare but often associated with patients having severe neurodevelopmental disorders with varying range of symptoms such as intellectual disability, developmental delay and epilepsy. Patient symptoms likely arise from mutations disturbing the role that the encoded NMDA receptor subunit, GluN2B, plays at neuronal connections in the developing nervous system. In this study, we investigated the cell-autonomous effects of putative gain- (GoF) and loss-of-function (LoF) missense GRIN2B mutations on excitatory synapses onto CA1 pyramidal neurons in organotypic hippocampal slices. In the absence of both native GluN2A and GluN2B subunits, functional incorporation into synaptic NMDA receptors was attenuated for GoF mutants, or almost eliminated for LoF GluN2B mutants. NMDA-receptor-mediated excitatory postsynaptic currents (NMDA-EPSCs) from synaptic GoF GluN1/2B receptors had prolonged decays consistent with their functional classification. Nonetheless, in the presence of native GluN2A, molecular replacement of native GluN2B with GoF and LoF GluN2B mutants all led to similar functional incorporation into synaptic receptors, more rapidly decaying NMDA-EPSCs and greater inhibition by TCN-201, a selective antagonist for GluN2A-containing NMDA receptors. Mechanistic insight was gained from experiments in HEK293T cells, which revealed that GluN2B GoF mutants slowed deactivation in diheteromeric GluN1/2B, but not triheteromeric GluN1/2A/2B receptors. We also show that a disease-associated missense mutation, which severely affects surface expression, causes opposing effects on NMDA-EPSC decay and charge transfer when introduced into GluN2A or GluN2B. Finally, we show that having a single null Grin2b allele has only a modest effect on NMDA-EPSC decay kinetics. Our results demonstrate that functional incorporation of GoF and LoF GluN2B mutants into synaptic receptors and the effects on EPSC decay times are highly dependent on the presence of triheteromeric GluN1/2A/2B NMDA receptors, thereby influencing the functional classification of NMDA receptor variants as GoF or LoF mutations. These findings highlight the complexity of interpreting effects of disease-causing NMDA receptor missense mutations in the context of neuronal function.
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Lipina T, Men X, Blundell M, Salahpour A, Ramsey AJ. Abnormal sensory perception masks behavioral performance of Grin1 knockdown mice. GENES, BRAIN, AND BEHAVIOR 2022; 21:e12825. [PMID: 35705513 PMCID: PMC9744498 DOI: 10.1111/gbb.12825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 11/28/2022]
Abstract
The development and function of sensory systems require intact glutamatergic neurotransmission. Changes in touch sensation and vision are common symptoms in autism spectrum disorders, where altered glutamatergic neurotransmission is strongly implicated. Further, cortical visual impairment is a frequent symptom of GRIN disorder, a rare genetic neurodevelopmental disorder caused by pathogenic variants of GRIN genes that encode NMDA receptors. We asked if Grin1 knockdown mice (Grin1KD), as a model of GRIN disorder, had visual impairments resulting from NMDA receptor deficiency. We discovered that Grin1KD mice had deficient visual depth perception in the visual cliff test. Since Grin1KD mice are known to display robust changes in measures of learning, memory, and emotionality, we asked whether deficits in these higher-level processes could be partly explained by their visual impairment. By changing the experimental conditions to improve visual signals, we observed significant improvements in the performance of Grin1KD mice in tests that measure spatial memory, executive function, and anxiety. We went further and found destabilization of the outer segment of retina together with the deficient number and size of Meissner corpuscles (mechanical sensor) in the hind paw of Grin1KD mice. Overall, our findings suggest that abnormal sensory perception can mask the expression of emotional, motivational and cognitive behavior of Grin1KD mice. This study demonstrates new methods to adapt routine behavioral paradigms to reveal the contribution of vision and other sensory modalities in cognitive performance.
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Affiliation(s)
- Tatiana Lipina
- Department of Pharmacology & ToxicologyUniversity of TorontoTorontoOntarioCanada
| | - Xiaoyu Men
- Department of Pharmacology & ToxicologyUniversity of TorontoTorontoOntarioCanada
| | - Matisse Blundell
- Department of PhysiologyUniversity of TorontoTorontoOntarioCanada
| | - Ali Salahpour
- Department of Pharmacology & ToxicologyUniversity of TorontoTorontoOntarioCanada
| | - Amy J. Ramsey
- Department of Pharmacology & ToxicologyUniversity of TorontoTorontoOntarioCanada
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Kysilov B, Hrcka Krausova B, Vyklicky V, Smejkalova T, Korinek M, Horak M, Chodounska H, Kudova E, Cerny J, Vyklicky L. Pregnane-based steroids are novel positive NMDA receptor modulators that may compensate for the effect of loss-of-function disease-associated GRIN mutations. Br J Pharmacol 2022; 179:3970-3990. [PMID: 35318645 DOI: 10.1111/bph.15841] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 02/24/2022] [Accepted: 03/04/2022] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND AND PURPOSE N-methyl-D-aspartate receptors (NMDARs) play a critical role in synaptic plasticity, and mutations in human genes encoding NMDAR subunits have been described in individuals with various neuropsychiatric disorders. Compounds with a positive allosteric effect are thought to compensate for reduced receptor function. EXPERIMENTAL APPROACH We have used whole-cell patch-clamp electrophysiology on recombinant rat NMDARs and human variants found in individuals with neuropsychiatric disorders, in combination with in silico modelling, to explore the site of action of novel epipregnanolone-based NMDAR modulators. KEY RESULTS Analysis of the action of 4-(20-oxo-5β-pregnan-3β-yl) butanoic acid (EPA-But) at the NMDAR indicates that the effect of this steroid with a "bent" structure is different from that of cholesterol and oxysterols and shares a disuse-dependent mechanism of NMDAR potentiation with the "planar" steroid 20-oxo-pregn-5-en-3β-yl sulfate (PE-S). The potentiating effects of EPA-But and PE-S are additive. Alanine scan mutagenesis identified residues that reduce the potentiating effect of EPA-But. No correlation was found between the effects of EPA-But and PE-S at mutated receptors that were less sensitive to either steroid. The relative degree of potentiation induced by the two steroids also differed in human NMDARs carrying rare variants of hGluN1 or hGluN2B subunits found in individuals with neuropsychiatric disorders, including intellectual disability, epilepsy, developmental delay, and autism spectrum disorder. CONCLUSION AND IMPLICATIONS Our results show novel sites of action for pregnanolones at the NMDAR and provide an opportunity for the development of new therapeutic neurosteroid-based ligands to treat diseases associated with glutamatergic system hypofunction.
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Affiliation(s)
- Bohdan Kysilov
- Institute of Physiology CAS, Prague 4, Czech Republic.,Third Faculty of Medicine, Charles University in Prague, Prague 10, Czech Republic
| | | | | | | | | | - Martin Horak
- Institute of Physiology CAS, Prague 4, Czech Republic
| | - Hana Chodounska
- Institute of Organic Chemistry and Biochemistry CAS, Prague 6, Czech Republic
| | - Eva Kudova
- Institute of Organic Chemistry and Biochemistry CAS, Prague 6, Czech Republic
| | - Jiri Cerny
- Institute of Physiology CAS, Prague 4, Czech Republic
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Wang X, Guo Z, Mei D, Zhang Y, Zhao S, Hu S, Luo S, Wang Q, Gao C. The GluN2B-Trp373 NMDA Receptor Variant is Associated with Autism-, Epilepsy-Related Phenotypes and Reduces NMDA Receptor Currents in Rats. Neurochem Res 2022; 47:1588-1597. [PMID: 35181828 DOI: 10.1007/s11064-022-03554-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 02/02/2022] [Accepted: 02/07/2022] [Indexed: 11/30/2022]
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental condition with core clinical features of abnormal communication, social interactions, atypical intelligence, and a higher risk of epilepsy. Prior work has suggested that de novo heterozygous mutations in the GRIN2B gene that encodes the GluN2B subunit of N-methyl-D-aspartic acid receptors are likely linked to ASD. However, whether GLuN2B-Trp373 mutation derived from autistic individuals causes ASD-like behavioral aberrations in rats remains to be determined. Here, through in utero electroporation and in vivo studies, we conducted a battery of tests to examine ASD-associated behaviors, cognitive impairments, and susceptibility to pentylenetetrazol-induced seizures. Whole-cell patch recording was utilized to determine whether the GluN2B-Trp373 mutation influences GluN2B-containing NMDA receptor currents in rats. Results show that, behaviorally, GLuN2B-Trp373 mutant rats exhibited core behavioral manifestations of ASD, such as social interaction deficits, increases in stereotyped behaviors and anxiety stereotyped/repetitive, impaired spatial memory, and enhanced risk of pentylenetetrazol-induced seizures, consistent with many of the hallmarks of low-functioning ASD in humans. Functionally, the GluN2B-Trp373 mutation results in reduced GluN2B surface protein expression together with decreased hippocampal NMDA receptor currents. Collectively, our findings highlight that GluN2B-Trp373 mutations can drive the manifestation of ASD-associated symptoms via the suppression of NMDA receptor currents.
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Affiliation(s)
- Xiaona Wang
- Henan Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Neurodevelopment Engineering Research Center for Children, Children's Hospital Affiliated to Zhengzhou University, 33 Longhu Outer Circle Dong Road, Zhengzhou, 450018, Henan, China.
| | - Zhiyue Guo
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China
| | - Daoqi Mei
- Department of Neurology, Children's Hospital Affiliated to Zhengzhou University, Zhengzhou, China
| | - Yaodong Zhang
- Henan Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Neurodevelopment Engineering Research Center for Children, Children's Hospital Affiliated to Zhengzhou University, 33 Longhu Outer Circle Dong Road, Zhengzhou, 450018, Henan, China
| | - Shuai Zhao
- Henan Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Neurodevelopment Engineering Research Center for Children, Children's Hospital Affiliated to Zhengzhou University, 33 Longhu Outer Circle Dong Road, Zhengzhou, 450018, Henan, China
| | - Shunan Hu
- Henan Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Neurodevelopment Engineering Research Center for Children, Children's Hospital Affiliated to Zhengzhou University, 33 Longhu Outer Circle Dong Road, Zhengzhou, 450018, Henan, China
| | - Shuying Luo
- Henan Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Neurodevelopment Engineering Research Center for Children, Children's Hospital Affiliated to Zhengzhou University, 33 Longhu Outer Circle Dong Road, Zhengzhou, 450018, Henan, China
| | - Qi Wang
- Department of Histology and Embryology, School of Basic Medicine, Guizhou Medical University, Dongqing Road, Guiyang, 550025, Guizhou, China.
| | - Chao Gao
- Department of Rehabilitation, Children's Hospital Affiliated to Zhengzhou University, Zhengzhou, China.
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Chen S, Xu D, Fan L, Fang Z, Wang X, Li M. Roles of N-Methyl-D-Aspartate Receptors (NMDARs) in Epilepsy. Front Mol Neurosci 2022; 14:797253. [PMID: 35069111 PMCID: PMC8780133 DOI: 10.3389/fnmol.2021.797253] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022] Open
Abstract
Epilepsy is one of the most common neurological disorders characterized by recurrent seizures. The mechanism of epilepsy remains unclear and previous studies suggest that N-methyl-D-aspartate receptors (NMDARs) play an important role in abnormal discharges, nerve conduction, neuron injury and inflammation, thereby they may participate in epileptogenesis. NMDARs belong to a family of ionotropic glutamate receptors that play essential roles in excitatory neurotransmission and synaptic plasticity in the mammalian CNS. Despite numerous studies focusing on the role of NMDAR in epilepsy, the relationship appeared to be elusive. In this article, we reviewed the regulation of NMDAR and possible mechanisms of NMDAR in epilepsy and in respect of onset, development, and treatment, trying to provide more evidence for future studies.
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33
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Two new cases of nonepileptic neurodevelopmental disorder due to GRIN2B variants and detailed clinical description of the behavioral phenotype. Clin Dysmorphol 2021; 31:74-78. [DOI: 10.1097/mcd.0000000000000408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Gale JR, Kosobucki GJ, Hartnett-Scott KA, Aizenman E. Imprecision in Precision Medicine: Differential Response of a Disease-Linked GluN2A Mutant to NMDA Channel Blockers. Front Pharmacol 2021; 12:773455. [PMID: 34776984 PMCID: PMC8581401 DOI: 10.3389/fphar.2021.773455] [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: 09/09/2021] [Accepted: 10/13/2021] [Indexed: 11/13/2022] Open
Abstract
Mutations in N-methyl-d-aspartate receptors (NMDAR) subunits have been implicated in a growing number of human neurodevelopmental disorders. Previously, a de novo mutation in GRIN2A, encoding the GluN2A subunit, was identified in a patient with severe epilepsy and developmental delay. This missense mutation, which leads to GluN2A-P552R, produces significant dendrotoxicity in transfected rodent cortical neurons, as evidenced by pronounced dendritic blebbing. This injurious process can be prevented by treatment with the NMDA antagonist memantine. Given the increasing use of FDA approved NMDA antagonists to treat patients with GRIN mutations, who may have seizures refractory to traditional anti-epileptic drugs, we investigated whether additional NMDA antagonists were effective in attenuating neurotoxicity associated with GluN2A-P552R expression. Intriguingly, we found that while treatment with memantine can effectively block GluN2A-P552R-mediated dendrotoxicity, treatment with ketamine does not, despite the fact that both drugs work as open NMDAR channel blockers. Interestingly, we found that neurons expressing GluN2A-P552R were more vulnerable to an excitotoxic insult-an effect that, in this case, could be equally rescued by both memantine and ketamine. These findings suggest that GluN2A-P552R induced dendrotoxicity and increased vulnerability to excitotoxic stress are mediated through two distinct mechanisms. The differences between memantine and ketamine in halting GluN2A-P552R dendrotoxicity could not be explained by NMDA antagonist induced changes in MAP or Src kinase activation, previously shown to participate in NMDA-induced excitotoxicity. Our findings strongly suggest that not all NMDA antagonists may be of equal clinical utility in treating GRIN2A-mediated neurological disorders, despite a shared mechanism of action.
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Affiliation(s)
- Jenna R Gale
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Gabrielle J Kosobucki
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Karen A Hartnett-Scott
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Elias Aizenman
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
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35
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Marini C, Giardino M. Novel treatments in epilepsy guided by genetic diagnosis. Br J Clin Pharmacol 2021; 88:2539-2551. [PMID: 34778987 DOI: 10.1111/bcp.15139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 10/22/2021] [Accepted: 11/04/2021] [Indexed: 12/21/2022] Open
Abstract
In recent years, precision medicine has emerged as a new paradigm for improved and more individualized patient care. Its key objective is to provide the right treatment, to the right patient at the right time, by basing medical decisions on individual characteristics, including specific genetic biomarkers. In order to realize this objective researchers and physicians must first identify the underlying genetic cause; over the last 10 years, advances in genetics have made this possible for several monogenic epilepsies. Through next generation techniques, a precise genetic aetiology is attainable in 30-50% of genetic epilepsies beginning in the paediatric age. While committed in such search for novel genes carrying disease-causing variants, progress in the study of experimental models of epilepsy has also provided a better understanding of the mechanisms underlying the condition. Such advances are already being translated into improving care, management and treatment of some patients. Identification of a precise genetic aetiology can already direct physicians to prescribe treatments correcting specific metabolic defects, avoid antiseizure medicines that might aggravate functional consequences of the disease-causing variant or select the drugs that counteract the underlying, genetically determined, functional disturbance. Personalized, tailored treatments should not just focus on how to stop seizures but possibly prevent their onset and cure the disorder, often consisting of seizures and its comorbidities including cognitive, motor and behaviour deficiencies. This review discusses the therapeutic implications following a specific genetic diagnosis and the correlation between genetic findings, pathophysiological mechanisms and tailored seizure treatment, emphasizing the impact on current clinical practice.
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Affiliation(s)
- Carla Marini
- Child Neurology and Psychiatric Unit, Pediatric Hospital G. Salesi, United Hospitals of Ancona, Ancona, Italy
| | - Maria Giardino
- Child Neurology and Psychiatric Unit, Pediatric Hospital G. Salesi, United Hospitals of Ancona, Ancona, Italy
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36
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Inherited Developmental and Epileptic Encephalopathies. Neurol Int 2021; 13:555-568. [PMID: 34842787 PMCID: PMC8628919 DOI: 10.3390/neurolint13040055] [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: 09/16/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 01/13/2023] Open
Abstract
Epileptic encephalopathies often have a genetic etiology. The epileptic activity itself exerts a direct detrimental effect on neurodevelopment, which may add to the cognitive impairment induced by the underlying mutation (“developmental and epileptic encephalopathy”). The focus of this review is on inherited syndromes. The phenotypes of genetic disorders affecting ion channels, metabolic signalling, membrane trafficking and exocytosis, cell adhesion, cell growth and proliferation are discussed. Red flags suggesting family of genes or even specific genes are highlighted. The knowledge of the phenotypical spectrum can indeed prompt the clinician to suspect specific etiologies, expediting the diagnosis.
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Pejčić A, Janković SM, Đešević M, Gojak R, Lukić S, Marković N, Milosavljević M. Novel and emerging therapeutics for genetic epilepsies. Expert Rev Neurother 2021; 21:1283-1301. [PMID: 34633254 DOI: 10.1080/14737175.2021.1992275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Disease-specific treatments are available only for a minority of patients with genetic epilepsies, while the rest are treated with anticonvulsants, which are ineffective in almost one-third of patients. AREAS COVERED Recently approved and the most effective emerging therapeutics under development for the treatment of genetic epilepsies are overviewed after systematic search and analysis of relevant literature. EXPERT OPINION New and emerging drugs for genetic epilepsies exploit one of the two approaches: inhibiting hyperactive brain foci through blocking excitatory or augmenting inhibitory neurotransmission, or correcting the underlying genetic defect. The first is limited by insufficient selectivity of available compounds, and the second by imperfection of currently used vectors of genetic material, unselective and transient transgene expression. Besides, the treatment may come too late, after structural abnormalities and epilepsy deterioration takes place. However, with recent improvements, we can expect to see soon gradual decline in the number of patients with therapy-resistant genetic epilepsies.
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Affiliation(s)
- Ana Pejčić
- University of Kragujevac, Faculty of Medical Sciences, Kragujevac, Serbia
| | | | - Miralem Đešević
- Private Policlinic Center Eurofar Sarajevo, Cardiology Department, Sarajevo, Bosnia and Herzegovina
| | - Refet Gojak
- Infectious diseases Clinic, Clinical Center University of Sarajevo, Sarajevo, Bosnia and Herzegovina
| | - Snežana Lukić
- University of Kragujevac, Faculty of Medical Sciences, Kragujevac, Serbia
| | - Nenad Marković
- University of Kragujevac, Faculty of Medical Sciences, Kragujevac, Serbia
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Zaganas I, Vorgia P, Spilioti M, Mathioudakis L, Raissaki M, Ilia S, Giorgi M, Skoula I, Chinitrakis G, Michaelidou K, Paraskevoulakos E, Grafakou O, Kariniotaki C, Psyllou T, Zafeiris S, Tzardi M, Briassoulis G, Dinopoulos A, Mitsias P, Evangeliou A. Genetic cause of epilepsy in a Greek cohort of children and young adults with heterogeneous epilepsy syndromes. Epilepsy Behav Rep 2021; 16:100477. [PMID: 34568804 PMCID: PMC8449081 DOI: 10.1016/j.ebr.2021.100477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 08/17/2021] [Accepted: 08/23/2021] [Indexed: 12/01/2022] Open
Abstract
We describe a cohort of 10 unrelated Greek patients (4 females, 6 males; median age 6.5 years, range 2-18 years) with heterogeneous epilepsy syndromes with a genetic basis. In these patients, causative genetic variants, including two novel ones, were identified in 9 known epilepsy-related genes through whole exome sequencing. A patient with glycine encephalopathy was a compound heterozygote for the p.Arg222Cys and the p.Ser77Leu AMT variant. A patient affected with Lafora disease carried the homozygous p.Arg171His EPM2A variant. A de novo heterozygous variant in the GABRG2 gene (p.Pro282Thr) was found in one patient and a pathogenic variant in the GRIN2B gene (p.Gly820Val) in another patient. Infantile-onset lactic acidosis with seizures was associated with the p.Arg446Ter PDHX gene variant in one patient. In two additional epilepsy patients, the p.Ala1662Val and the novel non-sense p.Phe1330Ter SCN1A gene variants were found. Finally, in 3 patients we observed a novel heterozygous missense variant in SCN2A (p.Ala1874Thr), a heterozygous splice site variant in SLC2A1 (c.517-2A>G), as a cause of Glut1 deficiency syndrome, and a pathogenic variant in STXBP1 (p.Arg292Leu), respectively. In half of our cases (patients with variants in the GRIN2B, SCN1A, SCN2A and SLC2A1 genes), a genetic cause with potential management implications was identified.
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Affiliation(s)
- Ioannis Zaganas
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
- Neurology Department, University Hospital of Heraklion, Crete, Greece
| | - Pelagia Vorgia
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Martha Spilioti
- AHEPA General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Lambros Mathioudakis
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Maria Raissaki
- Department of Radiology, University Hospital of Heraklion, Crete, Greece
| | - Stavroula Ilia
- Pediatric Intensive Care Unit, University Hospital of Heraklion, Crete, Greece
| | | | - Irene Skoula
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | | | - Kleita Michaelidou
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | | | - Olga Grafakou
- Pediatric Department, Venizelion General Hospital, Heraklio, Crete, Greece
| | - Chariklia Kariniotaki
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Thekla Psyllou
- Neurogenetics Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Spiros Zafeiris
- Neurology Department, University Hospital of Heraklion, Crete, Greece
| | - Maria Tzardi
- Pathology Department, Medical School, University of Crete, Greece
| | - George Briassoulis
- Pediatric Intensive Care Unit, University Hospital of Heraklion, Crete, Greece
| | | | - Panayiotis Mitsias
- Neurology Department, University Hospital of Heraklion, Crete, Greece
- Department of Neurology, Henry Ford Hospital/Wayne State University, Detroit, MI, USA
| | - Athanasios Evangeliou
- Papageorgiou General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Abstract
The presence of unprovoked, recurrent seizures, particularly when drug resistant and associated with cognitive and behavioral deficits, warrants investigation for an underlying genetic cause. This article provides an overview of the major classes of genes associated with epilepsy phenotypes divided into functional categories along with the recommended work-up and therapeutic considerations. Gene discovery in epilepsy supports counseling and anticipatory guidance but also opens the door for precision medicine guiding therapy with a focus on those with disease-modifying effects.
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Affiliation(s)
- Luis A Martinez
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Yi-Chen Lai
- Department of Pediatrics, Section of Pediatric Critical Care Medicine, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - J Lloyd Holder
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Anne E Anderson
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA.
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Wolking S, Moreau C, McCormack M, Krause R, Krenn M, Berkovic S, Cavalleri GL, Delanty N, Depondt C, Johnson MR, Koeleman BPC, Kunz WS, Lerche H, Marson AG, O’Brien TJ, Petrovski S, Sander JW, Sills GJ, Striano P, Zara F, Zimprich F, Sisodiya SM, Girard SL, Cossette P. Assessing the role of rare genetic variants in drug-resistant, non-lesional focal epilepsy. Ann Clin Transl Neurol 2021; 8:1376-1387. [PMID: 34018700 PMCID: PMC8283173 DOI: 10.1002/acn3.51374] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 03/08/2021] [Accepted: 04/14/2021] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVE Resistance to antiseizure medications (ASMs) is one of the major concerns in the treatment of epilepsy. Despite the increasing number of ASMs available, the proportion of individuals with drug-resistant epilepsy remains unchanged. In this study, we aimed to investigate the role of rare genetic variants in ASM resistance. METHODS We performed exome sequencing of 1,128 individuals with non-familial non-acquired focal epilepsy (NAFE) (762 non-responders, 366 responders) and were provided with 1,734 healthy controls. We undertook replication in a cohort of 350 individuals with NAFE (165 non-responders, 185 responders). We performed gene-based and gene-set-based kernel association tests to investigate potential enrichment of rare variants in relation to drug response status and to risk for NAFE. RESULTS We found no gene or gene set that reached genome-wide significance. Yet, we identified several prospective candidate genes - among them DEPDC5, which showed a potential association with resistance to ASMs. We found some evidence for an enrichment of truncating variants in dominant familial NAFE genes in our cohort of non-familial NAFE and in association with drug-resistant NAFE. INTERPRETATION Our study identifies potential candidate genes for ASM resistance. Our results corroborate the role of rare variants for non-familial NAFE and imply their involvement in drug-resistant epilepsy. Future large-scale genetic research studies are needed to substantiate these findings.
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Affiliation(s)
- Stefan Wolking
- Université de MontréalMontrealCanada
- Neurology and EpileptologyHertie Institute for Clinical Brain ResearchUniversity of TübingenTübingenGermany
- Department of Epileptology and NeurologyUniversity of AachenAachenGermany
| | - Claudia Moreau
- Centre Intersectoriel en Santé DurableUniversité du Québec à ChicoutimiSaguenayCanada
| | - Mark McCormack
- Molecular and Cellular TherapeuticsRoyal College of Surgeons in IrelandDublinIreland
| | - Roland Krause
- Luxembourg Centre for Systems BiomedicineUniversity of LuxembourgEsch‐sur‐AlzetteLuxembourg
| | - Martin Krenn
- Department of NeurologyMedical University of ViennaViennaAustria
| | | | - Samuel Berkovic
- Department of MedicineEpilepsy Research Centre, Austin HealthUniversity of MelbourneMelbourneAustralia
- Department of NeurologyAustin HealthHeidelbergAustralia
| | - Gianpiero L. Cavalleri
- Department of Molecular and Cellular TherapeuticsRoyal College of Surgeons in IrelandDublinIreland
- FutureNeuro Research CentreScience Foundation IrelandDublinIreland
- Division of Brain SciencesImperial College Faculty of MedicineLondonUK
| | - Norman Delanty
- Department of Molecular and Cellular TherapeuticsRoyal College of Surgeons in IrelandDublinIreland
- FutureNeuro Research CentreScience Foundation IrelandDublinIreland
- Division of NeurologyBeaumont HospitalDublinIreland
| | - Chantal Depondt
- Department of NeurologyHôpital ErasmeUniversité Libre de BruxellesBrusselsBelgium
| | | | | | - Wolfram S. Kunz
- Institute of Experimental Epileptology and Cognition Research and Department of EpileptologyUniversity of BonnBonnGermany
| | - Holger Lerche
- Neurology and EpileptologyHertie Institute for Clinical Brain ResearchUniversity of TübingenTübingenGermany
| | - Anthony G. Marson
- Department of Molecular and Clinical PharmacologyInstitute of Translational MedicineUniversity of LiverpoolLiverpoolUK
- The Walton Centre NHS Foundation TrustLiverpoolUK
- Liverpool Health PartnersLiverpoolUK
| | - Terence J. O’Brien
- Departments of Medicine and NeurologyRoyal Melbourne HospitalUniversity of MelbourneParkvilleAustralia
- Departments of Neuroscience and NeurologyThe Central Clinical SchoolMonash University and The Alfred HospitalMelbourneAustralia
| | - Slave Petrovski
- Centre for Genomics Research, Discovery Sciences, BioPharmaceuticals R&DAstraZenecaCambridgeUK
| | - Josemir W. Sander
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
- Chalfont Centre for EpilepsyChalfont‐St‐PeterUK
- Stichting Epilepsie Instellingen Nederland (SEIN)HeemstedeNetherlands
| | | | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases UnitIRCCS "G. Gaslini" InstituteGenovaItaly
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child HealthUniversity of GenoaGenovaItaly
| | - Federico Zara
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child HealthUniversity of GenoaGenovaItaly
- Laboratory of Neurogenetics and NeuroscienceIRCCS "G. Gaslini" InstituteGenovaItaly
| | - Fritz Zimprich
- Department of NeurologyMedical University of ViennaViennaAustria
| | - Sanjay M. Sisodiya
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
- Chalfont Centre for EpilepsyChalfont‐St‐PeterUK
| | - Simon L. Girard
- Centre Intersectoriel en Santé DurableUniversité du Québec à ChicoutimiSaguenayCanada
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Kim MH, Kim IB, Lee J, Cha DH, Park SM, Kim JH, Kim R, Park JS, An Y, Kim K, Kim S, Webster MJ, Kim S, Lee JH. Low-Level Brain Somatic Mutations Are Implicated in Schizophrenia. Biol Psychiatry 2021; 90:35-46. [PMID: 33867114 DOI: 10.1016/j.biopsych.2021.01.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/08/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND Somatic mutations arising from the brain have recently emerged as significant contributors to neurodevelopmental disorders, including childhood intractable epilepsy and cortical malformations. However, whether brain somatic mutations are implicated in schizophrenia (SCZ) is not well established. METHODS We performed deep whole exome sequencing (average read depth > 550×) of matched dorsolateral prefrontal cortex and peripheral tissues from 27 patients with SCZ and 31 age-matched control individuals, followed by comprehensive and strict analysis of somatic mutations, including mutagenesis signature, substitution patterns, and involved pathways. In particular, we explored the impact of deleterious mutations in GRIN2B through primary neural culture. RESULTS We identified an average of 4.9 and 5.6 somatic mutations per exome per brain in patients with SCZ and control individuals, respectively. These mutations presented with average variant allele frequencies of 8.0% in patients with SCZ and 7.6% in control individuals. Although mutational profiles, such as the number and type of mutations, showed no significant difference between patients with SCZ and control individuals, somatic mutations in SCZ brains were significantly enriched for SCZ-related pathways, including dopamine receptor, glutamate receptor, and long-term potentiation pathways. Furthermore, we showed that brain somatic mutations in GRIN2B (encoding glutamate ionotropic NMDA receptor subunit 2B), which were found in two patients with SCZ, disrupted the location of GRIN2B across the surface of dendrites among primary cultured neurons. CONCLUSIONS Taken together, this study shows that brain somatic mutations are associated with the pathogenesis of SCZ.
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Affiliation(s)
- Myeong-Heui Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Il Bin Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea; Department of Psychiatry, Hanyang University Guri Hospital, Guri, Republic of Korea
| | - Junehawk Lee
- Center for Computational Science Platform, National Institute of Supercomputing and Networking, Korea Institute of Science and Technology Information, Daejeon, Republic of Korea
| | - Do Hyeon Cha
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Sang Min Park
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Ja Hye Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Ryunhee Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Jun Sung Park
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea; European Bioinformatics Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Yohan An
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Kyungdeok Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Seyeon Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Maree J Webster
- Stanley Medical Research Institute, Laboratory of Brain Research, Rockville, Maryland
| | - Sanghyeon Kim
- Stanley Medical Research Institute, Laboratory of Brain Research, Rockville, Maryland.
| | - Jeong Ho Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea; SoVarGen Inc., Daejeon, Republic of Korea.
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McDaniel MJ, Ogden KK, Kell SA, Burger PB, Liotta DC, Traynelis SF. NMDA receptor channel gating control by the pre-M1 helix. J Gen Physiol 2021; 152:151592. [PMID: 32221541 PMCID: PMC7141592 DOI: 10.1085/jgp.201912362] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 08/09/2019] [Accepted: 02/14/2020] [Indexed: 01/10/2023] Open
Abstract
The NMDA receptor (NMDAR) is an ionotropic glutamate receptor formed from the tetrameric assembly of GluN1 and GluN2 subunits. Within the flexible linker between the agonist binding domain (ABD) and the M1 helix of the pore-forming transmembrane helical bundle lies a two-turn, extracellular pre-M1 helix positioned parallel to the plasma membrane and in van der Waals contact with the M3 helix thought to constitute the channel gate. The pre-M1 helix is tethered to the bilobed ABD, where agonist-induced conformational changes initiate activation. Additionally, it is a locus for de novo mutations associated with neurological disorders, is near other disease-associated de novo sites within the transmembrane domain, and is a structural determinant of subunit-selective modulators. To investigate the role of the pre-M1 helix in channel gating, we performed scanning mutagenesis across the GluN2A pre-M1 helix and recorded whole-cell macroscopic and single channel currents from HEK293 cell-attached patches. We identified two residues at which mutations perturb channel open probability, the mean open time, and the glutamate deactivation time course. We identified a subunit-specific network of aromatic amino acids located in and around the GluN2A pre-M1 helix to be important for gating. Based on these results, we are able to hypothesize about the role of the pre-M1 helix in other NMDAR subunits based on sequence and structure homology. Our results emphasize the role of the pre-M1 helix in channel gating, implicate the surrounding amino acid environment in this mechanism, and suggest unique subunit-specific contributions of pre-M1 helices to GluN1 and GluN2 gating.
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Affiliation(s)
- Miranda J McDaniel
- Department of Pharmacology, Rollins Research Center, Emory University, Atlanta, GA
| | - Kevin K Ogden
- Department of Pharmacology, Rollins Research Center, Emory University, Atlanta, GA
| | - Steven A Kell
- Department of Pharmacology, Rollins Research Center, Emory University, Atlanta, GA.,Department of Chemistry, Emory University, Atlanta, GA
| | | | | | - Stephen F Traynelis
- Department of Pharmacology, Rollins Research Center, Emory University, Atlanta, GA
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Sapuppo A, Portale L, Massimino CR, Presti S, Tardino L, Marino S, Polizzi A, Falsaperla R, Praticò AD. GRIN2A and GRIN2B and Their Related Phenotypes. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractGlutamate is the most relevant excitatory neurotransmitter of the central nervous system; it binds with several receptors, including N-methyl-D-aspartate receptors (NMDARs), a subtype of ionotropic glutamate receptor that displays voltage-dependent block by Mg2+ and a high permeability to Ca2+. GRIN2A and GRIN2B genes encode the GluN2A and GluN2B subunits of the NMDARs, which play important roles in synaptogenesis, synaptic transmission, and synaptic plasticity, as well as contributing to neuronal loss and dysfunction in several neurological disorders. Recently, individuals with a range of childhood-onset drug-resistant epilepsies, such as Landau–Kleffner or Lennox–Gastaut syndrome, intellectual disability (ID), and other neurodevelopmental abnormalities have been found to carry mutations in GRIN2A and GRIN2B, with high variable expressivity in phenotype. The first one is found mainly in epilepsy-aphasia syndromes, while the second one mainly in autism, schizophrenia, and ID, such as autism spectrum disorders. Brain magnetic resonance imaging alterations are found in some patients, even if without a clear clinical correlation. At the same time, increasing data on genotype–phenotype correlation have been found, but this is still not fully demonstrated. There are no specific therapies for the treatment of correlated NMDARs epilepsy, although some evidence with memantine, an antagonist of glutamate receptor, is reported in the literature in selected cases with mutation determining a gain of function.
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Affiliation(s)
- Annamaria Sapuppo
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Laura Portale
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Carmela R. Massimino
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Santiago Presti
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Lucia Tardino
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Simona Marino
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Agata Polizzi
- Chair of Pediatrics, Department of Educational Sciences, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous Systemin Childhood, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
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KUTLUK G, RANDA NC. A Significant and Treatable Cause of Epileptic Encephalopathy: GRIN2D Mutation. ACTA MEDICA ALANYA 2021. [DOI: 10.30565/medalanya.891938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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45
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Proietti Onori M, van Woerden GM. Role of calcium/calmodulin-dependent kinase 2 in neurodevelopmental disorders. Brain Res Bull 2021; 171:209-220. [PMID: 33774142 DOI: 10.1016/j.brainresbull.2021.03.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 01/28/2023]
Abstract
Neurodevelopmental disorders are a complex and heterogeneous group of neurological disorders characterized by their early-onset and estimated to affect more than 3% of children worldwide. The rapid advancement of sequencing technologies in the past years allowed the identification of hundreds of variants in several different genes causing neurodevelopmental disorders. Between those, new variants in the Calcium/calmodulin dependent protein kinase II (CAMK2) genes were recently linked to intellectual disability. Despite many years of research on CAMK2, this proves for the first time that this well-known and highly conserved molecule plays an important role in the human brain. In this review, we give an overview of the identified CAMK2 variants, and we speculate on potential mechanisms through which dysfunctions in CAMK2 result in neurodevelopmental disorders. Additionally, we discuss how the identification of CAMK2 variants might result in new exciting discoveries regarding the function of CAMK2 in the human brain.
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Affiliation(s)
- Martina Proietti Onori
- Department of Neuroscience, Erasmus MC, Rotterdam, 3015 GD, the Netherlands; The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC, Rotterdam, 3015 GD, the Netherlands
| | - Geeske M van Woerden
- Department of Neuroscience, Erasmus MC, Rotterdam, 3015 GD, the Netherlands; The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC, Rotterdam, 3015 GD, the Netherlands.
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Polymicrogyria with calcification in Pallister-Killian syndrome detected by microarray analysis. Brain Dev 2021; 43:448-453. [PMID: 33229101 DOI: 10.1016/j.braindev.2020.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/28/2020] [Accepted: 11/06/2020] [Indexed: 11/21/2022]
Abstract
BACKGROUND Pallister-Killian syndrome (PKS) is a rare disorder caused by the mosaic tetrasomy of chromosome 12p, and is characterized by facial dysmorphism, developmental delay, hypotonia and seizures. RESULTS We report a patient with PKS showing unique polymicrogyria with calcification. He had delayed development and dysmorphic facial features including frontal bossing, hypertelorism, and high arched palate at 6 months of age. Neuroimaging revealed unilateral polymicrogyria with spot calcifications, which predominantly affected the right perisylvian region. Chromosome G-banding showed the karyotype 46,XY, however, array-based comparative genomic hybridization analysis showed mosaic duplication of chromosome 12p, in which CCND2, which encodes cyclin D2 and is a downstream mediator of PI3K-AKT pathway, is located. Supernumerary chromosome of 12p was detected in 58% of buccal mucosa cells by the interphase fluorescence in situ hybridization analysis using chromosome 12 centromere-specific D12Z3 probe. The diagnosis of PKS was made based on distinctive clinical features of our patient and the results of cytogenetic analyses. CONCLUSION This report is, to our knowledge, the first case of a patient with PKS who clearly demonstrates polymicrogyria colocalized with calcifications, as shown by CT scans and MRI, and suggests that a patient with PKS could show structural brain anomalies with calcification. We assume that somatic mosaicism of tetrasomy could cause asymmetrical polymicrogyria in our patient, and speculate that increased dosages of CCND2 at chromosome 12p might be involved in the abnormal neuronal migration in PKS.
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Hyder Z, Van Paesschen W, Sabir A, Sansbury FH, Burke KB, Khan N, Chandler KE, Cooper NS, Wright R, McHale E, Van Esch H, Banka S. ERBB4 exonic deletions on chromosome 2q34 in patients with intellectual disability or epilepsy. Eur J Hum Genet 2021; 29:1377-1383. [PMID: 33603162 PMCID: PMC8440581 DOI: 10.1038/s41431-021-00815-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/09/2020] [Accepted: 01/19/2021] [Indexed: 11/09/2022] Open
Abstract
ERBB4 encodes the tyrosine kinase receptor HER4, a critical regulator of normal cell function and neurodevelopmental processes in the brain. One of the key ligands of HER4 is neureglin-1 (NRG1), and the HER4-NRG1 signalling pathway is essential in neural crest cell migration, and neuronal differentiation. Pharmacological inactivation of HER4 has been shown to hasten the progression of epileptogenesis in rodent models, and heterozygous ERBB4 null mice are shown to have cognitive deficits and delayed motor development. Thus far there is only a single case report in the literature of a heterozygous ERBB4 deletion in a patient with intellectual disability (ID). We identified nine subjects from five unrelated families with chromosome 2q34 deletions, resulting in heterozygous intragenic loss of multiple exons of ERBB4, associated with either non-syndromic ID or generalised epilepsy. In one family, the deletion segregated with ID in five affected relatives. Overall, this case series further supports that haploinsufficiency of ERBB4 leads to non-syndromic intellectual disability or epilepsy.
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Affiliation(s)
- Zerin Hyder
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK.
| | - Wim Van Paesschen
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium.,Laboratory for Epilepsy Research, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Ataf Sabir
- West Midlands Regional Genetics Service, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
| | - Francis H Sansbury
- All Wales Medical Genomics Service, NHS Wales Cardiff and Vale University Health Board, Institute of Medical Genetics, University Hospital of Wales, Cardiff, UK
| | - Katherine B Burke
- All Wales Medical Genomics Service, NHS Wales Cardiff and Vale University Health Board, Institute of Medical Genetics, University Hospital of Wales, Cardiff, UK
| | - Naz Khan
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Kate E Chandler
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK.,Division of Evolution & Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Nicola S Cooper
- West Midlands Regional Genetics Service, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
| | - Ronnie Wright
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Edward McHale
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Hilde Van Esch
- Center for Human Genetics, University Hospitals Leuven, University of Leuven, Leuven, Belgium
| | - Siddharth Banka
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK.,Division of Evolution & Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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Voltage-independent GluN2A-type NMDA receptor Ca 2+ signaling promotes audiogenic seizures, attentional and cognitive deficits in mice. Commun Biol 2021; 4:59. [PMID: 33420383 PMCID: PMC7794508 DOI: 10.1038/s42003-020-01538-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 11/20/2020] [Indexed: 12/21/2022] Open
Abstract
The NMDA receptor-mediated Ca2+ signaling during simultaneous pre- and postsynaptic activity is critically involved in synaptic plasticity and thus has a key role in the nervous system. In GRIN2-variant patients alterations of this coincidence detection provoked complex clinical phenotypes, ranging from reduced muscle strength to epileptic seizures and intellectual disability. By using our gene-targeted mouse line (Grin2aN615S), we show that voltage-independent glutamate-gated signaling of GluN2A-containing NMDA receptors is associated with NMDAR-dependent audiogenic seizures due to hyperexcitable midbrain circuits. In contrast, the NMDAR antagonist MK-801-induced c-Fos expression is reduced in the hippocampus. Likewise, the synchronization of theta- and gamma oscillatory activity is lowered during exploration, demonstrating reduced hippocampal activity. This is associated with exploratory hyperactivity and aberrantly increased and dysregulated levels of attention that can interfere with associative learning, in particular when relevant cues and reward outcomes are disconnected in space and time. Together, our findings provide (i) experimental evidence that the inherent voltage-dependent Ca2+ signaling of NMDA receptors is essential for maintaining appropriate responses to sensory stimuli and (ii) a mechanistic explanation for the neurological manifestations seen in the NMDAR-related human disorders with GRIN2 variant-meidiated intellectual disability and focal epilepsy. Ilaria Bertocchi et al. use a mouse model of Grin2a dysfunction to show that activity-independent NMDA receptors are involved in audiogenic seizure generation. Their results suggest a role for NMDA receptors in maintaining an appropriate response to sensory stimuli and a potential mechanism for disease phenotypes in epilepsy patients with GRIN2A mutations.
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Phillips MB, Nigam A, Johnson JW. Interplay between Gating and Block of Ligand-Gated Ion Channels. Brain Sci 2020; 10:brainsci10120928. [PMID: 33271923 PMCID: PMC7760600 DOI: 10.3390/brainsci10120928] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/21/2020] [Accepted: 11/26/2020] [Indexed: 02/03/2023] Open
Abstract
Drugs that inhibit ion channel function by binding in the channel and preventing current flow, known as channel blockers, can be used as powerful tools for analysis of channel properties. Channel blockers are used to probe both the sophisticated structure and basic biophysical properties of ion channels. Gating, the mechanism that controls the opening and closing of ion channels, can be profoundly influenced by channel blocking drugs. Channel block and gating are reciprocally connected; gating controls access of channel blockers to their binding sites, and channel-blocking drugs can have profound and diverse effects on the rates of gating transitions and on the stability of channel open and closed states. This review synthesizes knowledge of the inherent intertwining of block and gating of excitatory ligand-gated ion channels, with a focus on the utility of channel blockers as analytic probes of ionotropic glutamate receptor channel function.
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Affiliation(s)
- Matthew B. Phillips
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.B.P.); (A.N.)
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Aparna Nigam
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.B.P.); (A.N.)
| | - Jon W. Johnson
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.B.P.); (A.N.)
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
- Correspondence: ; Tel.: +1-(412)-624-4295
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50
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García-Recio A, Santos-Gómez A, Soto D, Julia-Palacios N, García-Cazorla À, Altafaj X, Olivella M. GRIN database: A unified and manually curated repertoire of GRIN variants. Hum Mutat 2020; 42:8-18. [PMID: 33252190 DOI: 10.1002/humu.24141] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/13/2020] [Accepted: 11/16/2020] [Indexed: 12/22/2022]
Abstract
Glutamatergic neurotransmission is crucial for brain development, wiring neuronal function, and synaptic plasticity mechanisms. Recent genetic studies showed the existence of autosomal dominant de novo GRIN gene variants associated with GRIN-related disorders (GRDs), a rare pediatric neurological disorder caused by N-methyl- d-aspartate receptor (NMDAR) dysfunction. Notwithstanding, GRIN variants identification is exponentially growing and their clinical, genetic, and functional annotations remain highly fragmented, representing a bottleneck in GRD patient's stratification. To shorten the gap between GRIN variant identification and patient stratification, we present the GRIN database (GRINdb), a publicly available, nonredundant, updated, and curated database gathering all available genetic, functional, and clinical data from more than 4000 GRIN variants. The manually curated GRINdb outputs on a web server, allowing query and retrieval of reported GRIN variants, and thus representing a fast and reliable bioinformatics resource for molecular clinical advice. Furthermore, the comprehensive mapping of GRIN variants' genetic and clinical information along NMDAR structure revealed important differences in GRIN variants' pathogenicity and clinical phenotypes, shedding light on GRIN-specific fingerprints. Overall, the GRINdb and web server is a resource for molecular stratification of GRIN variants, delivering clinical and investigational insights into GRDs. GRINdb is accessible at http://lmc.uab.es/grindb.
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Affiliation(s)
- Adrián García-Recio
- Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Ana Santos-Gómez
- Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Neurophysiology Laboratory, Department of Biomedicine, Institute of Neurosciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - David Soto
- Neurophysiology Laboratory, Department of Biomedicine, Institute of Neurosciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain.,August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Hospital Clínic, University of Barcelona, Barcelona, Spain
| | - Natalia Julia-Palacios
- Neurometabolic Unit, Department of Neurology, Hospital Sant Joan de Déu and CIBERER, Barcelona, Spain
| | - Àngels García-Cazorla
- Neurometabolic Unit, Department of Neurology, Hospital Sant Joan de Déu and CIBERER, Barcelona, Spain
| | - Xavier Altafaj
- Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Neurophysiology Laboratory, Department of Biomedicine, Institute of Neurosciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
| | - Mireia Olivella
- School of International Studies, ESCI-UPF, Barcelona, Spain.,Bioinfomatics and Medical Statistics Group, University of Vic-Central University of Catalonia, Vic, Spain
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