1
|
Li RK, Xiong YR, Pan SJ, Lei WT, Shu XM, Shi XQ, Tian MQ. Role of TRAK1 variants in epilepsy: genotype-phenotype analysis in a pediatric case of epilepsy with developmental disorder. Front Mol Neurosci 2024; 17:1342371. [PMID: 38410694 PMCID: PMC10894949 DOI: 10.3389/fnmol.2024.1342371] [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: 11/21/2023] [Accepted: 01/23/2024] [Indexed: 02/28/2024] Open
Abstract
Purpose The TRAK1 gene is mapped to chromosome 3p22.1 and encodes trafficking protein kinesin binding 1. The aim of this study was to investigate the genotype-phenotype of TRAK1-associated epilepsy. Methods Trio-based whole-exome sequencing was performed on a cohort of 98 patients with epilepsy of unknown etiologies. Protein modeling and the VarCards database were used to predict the damaging effects of the variants. Detailed neurological phenotypes of all patients with epilepsy having TRAK1 variants were analyzed to assess the genotype-phenotype correlations. Results A novel TRAK1 compound heterozygous variant comprising variant c.835C > T, p.Arg279Cys and variant c.2560A > C, p.Lys854Gln was identified in one pediatric patient. Protein modeling and VarCards database analyses revealed that the variants were damaging. The patient received a diagnosis of early infantile epileptic spasms with a developmental disorder; he became seizure-free through valproate and adrenocorticotropic hormone treatment. Further results for six variants in 12 patients with epilepsy indicated that biallelic TRAK1 variants (including homozygous or compound heterozygous variants) were associated with epilepsy with developmental disorders. Among these patients, eight (67%) had epileptic spasms and seven (58%) were intractable to anti-seizure medicines. Moreover, eight patients experienced refractory status epilepticus, of which seven (88%) died in early life. To our knowledge, this is the first reported case of epilepsy caused by TRAK1 compound heterozygous variants. Conclusion Biallelic TRAK1 variants can cause epilepsy and developmental disorders. In these patients, seizures progress to status epilepticus, suggesting a high risk for poor outcomes and the requirement of early treatment.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Mao-Qiang Tian
- Department of Pediatrics, Affiliated Hospital of Zunyi Medical University, Children’s Hospital of Guizhou Province, Zunyi, China
| |
Collapse
|
2
|
Zhou YP, Normandin MD, Belov V, Macdonald-Soccorso MT, Moon SH, Sun Y, El Fakhri G, Guehl NJ, Brugarolas P. Evaluation of trans- and cis-4-[ 18F]Fluorogabapentin for Brain PET Imaging. ACS Chem Neurosci 2023; 14:4208-4215. [PMID: 37947793 DOI: 10.1021/acschemneuro.3c00593] [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] [Indexed: 11/12/2023] Open
Abstract
Gabapentin, a selective ligand for the α2δ subunit of voltage-dependent calcium channels, is an anticonvulsant medication used in the treatment of neuropathic pain, epilepsy, and other neurological conditions. We recently described two radiofluorinated derivatives of gabapentin (trans-4-[18F]fluorogabapentin, [18F]tGBP4F, and cis-4-[18F]fluorogabapentin, [18F]cGBP4F) and showed that these compounds accumulate in the injured nerves in a rodent model of neuropathic pain. Given the use of gabapentin in brain diseases, here we investigate whether these radiofluorinated derivatives of gabapentin can be used for imaging α2δ receptors in the brain. Specifically, we developed automated radiosynthesis methods for [18F]tGBP4F and [18F]cGBP4F and conducted dynamic PET imaging in adult rhesus macaques with and without preadministration of pharmacological doses of gabapentin. Both radiotracers showed very high metabolic stability, negligible plasma protein binding, and slow accumulation in the brain. [18F]tGBP4F, the isomer with higher binding affinity, showed low brain uptake and could not be displaced, whereas [18F]cGBP4F showed moderate brain uptake and could be partially displaced. Kinetic modeling of brain regional time-activity curves using a metabolite-corrected arterial input function shows that a one-tissue compartment model accurately fits the data. Graphical analysis using Logan or multilinear analysis 1 produced similar results as compartmental modeling, indicating robust quantification. This study advances our understanding of how gabapentinoids work and provides an important advancement toward imaging α2δ receptors in the brain.
Collapse
Affiliation(s)
- Yu-Peng Zhou
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Marc D Normandin
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Vasily Belov
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Marina T Macdonald-Soccorso
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Sung-Hyun Moon
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Yang Sun
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Georges El Fakhri
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Nicolas J Guehl
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Pedro Brugarolas
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, United States
| |
Collapse
|
3
|
Zhou YP, Normandin MD, Belov V, Macdonald-Soccorso MT, Moon SH, Sun Y, Fakhri GE, Guehl NJ, Brugarolas P. Evaluation of trans- and cis-4-[ 18F]fluorogabapentin for brain PET imaging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.01.555353. [PMID: 37732236 PMCID: PMC10508714 DOI: 10.1101/2023.09.01.555353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Gabapentin, a selective ligand for the α2δ subunit of voltage-dependent calcium channels, is an anticonvulsant medication used in the treatment of neuropathic pain, epilepsy and other neurological conditions. We recently described two radiofluorinated derivatives of gabapentin (trans-4-[18F]fluorogabapentin, [18F]tGBP4F, and cis-4-[18F]fluorogabapentin, [18F]cGBP4F) and showed that these compounds accumulate in the injured nerves in a rodent model of neuropathic pain. Given the use of gabapentin in brain diseases, here we investigate whether these radiofluorinated derivatives of gabapentin can be used for imaging α2δ receptors in the brain. Specifically, we developed automated radiosynthesis methods for [18F]tGBP4F and [18F]cGBP4F and conducted dynamic PET imaging in adult rhesus macaques with and without preadministration of pharmacological doses of gabapentin. Both radiotracers showed very high metabolic stability, negligible plasma protein binding and slow accumulation in the brain. [18F]tGBP4F, the isomer with higher binding affinity, showed low brain uptake and could not be displaced whereas [18F]cGBP4F showed moderate brain uptake and could be partially displaced. Kinetic modeling of brain regional time-activity curves using a metabolite-corrected arterial input function shows that a 1-tissue compartment model accurately fits the data. Graphical analysis using Logan or multilinear analysis 1 produced similar results as compartmental modeling indicating robust quantification. This study advances our understanding of how gabapentinoids work and provides an important advancement towards imaging α2δ receptors in the brain.
Collapse
Affiliation(s)
- Yu-Peng Zhou
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Marc D. Normandin
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Vasily Belov
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Marina T. Macdonald-Soccorso
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Sung-Hyun Moon
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Yang Sun
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Georges El Fakhri
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Nicolas J. Guehl
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Pedro Brugarolas
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
4
|
Wu H, Liu Y, Li H, Du C, Li K, Dong S, Meng Q, Zhang H. TRAK1-Mediated Abnormality of Mitochondrial Fission Increases Seizure Susceptibility in Temporal Lobe Epilepsy. Mol Neurobiol 2021; 58:1237-1247. [PMID: 33119838 DOI: 10.1007/s12035-020-02175-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 10/14/2020] [Indexed: 10/23/2022]
Abstract
Mitochondrial dysfunction is closely related to the occurrence of epilepsy. Homeostasis of mitochondrial fusion and division can alleviate mitochondrial dysfunction. The trafficking kinesin protein 1 (TRAK1) is a key regulator of mitochondrial movement and regulates mitochondrial fusion-fission balance. The pathogenic variants in TRAK1 result in the severe neurodevelopmental disorders. However, the role of TRAK1 in epilepsy remains unclear. In the present study, we report that TRAK1 has a crucial function in regulation of epileptogenesis in temporal lobe epilepsy (TLE). TRAK1 expression is decreased in the patient specimens and animal model of TLE. Knockdown of TRAK1 causes an increase in mitochondrial fission factor (MFF) in vitro and the susceptibility to seizures in vivo. Exogenous overexpression of TRAK1 can rescue the dysfunction caused by TRAK1 knockdown. These findings provide new insights into the fundamental mechanisms of TRAK1 in TLE and have important implications for understanding and treating TLE via targeting mitochondrion.
Collapse
Affiliation(s)
- Hao Wu
- Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shanxi, China
- Center of Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shanxi, China
| | - Yong Liu
- Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shanxi, China
| | - Huanfa Li
- Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shanxi, China
| | - Changwang Du
- Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shanxi, China
| | - Kuo Li
- Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shanxi, China
| | - Shan Dong
- Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shanxi, China
| | - Qiang Meng
- Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shanxi, China.
| | - Hua Zhang
- Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shanxi, China.
- Center of Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shanxi, China.
| |
Collapse
|
5
|
Geisler SM, Benedetti A, Schöpf CL, Schwarzer C, Stefanova N, Schwartz A, Obermair GJ. Phenotypic Characterization and Brain Structure Analysis of Calcium Channel Subunit α 2δ-2 Mutant (Ducky) and α 2δ Double Knockout Mice. Front Synaptic Neurosci 2021; 13:634412. [PMID: 33679366 PMCID: PMC7933509 DOI: 10.3389/fnsyn.2021.634412] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 01/11/2021] [Indexed: 01/19/2023] Open
Abstract
Auxiliary α2δ subunits of voltage-gated calcium channels modulate channel trafficking, current properties, and synapse formation. Three of the four isoforms (α2δ-1, α2δ-2, and α2δ-3) are abundantly expressed in the brain; however, of the available knockout models, only α2δ-2 knockout or mutant mice display an obvious abnormal neurological phenotype. Thus, we hypothesize that the neuronal α2δ isoforms may have partially specific as well as redundant functions. To address this, we generated three distinct α2δ double knockout mouse models by crossbreeding single knockout (α2δ-1 and -3) or mutant (α2δ-2/ducky) mice. Here, we provide a first phenotypic description and brain structure analysis. We found that genotypic distribution of neonatal litters in distinct α2δ-1/-2, α2δ-1/-3, and α2δ-2/-3 breeding combinations did not conform to Mendel's law, suggesting premature lethality of single and double knockout mice. Notably, high occurrences of infant mortality correlated with the absence of specific α2δ isoforms (α2Δ-2 > α2δ-1 > α2δ-3), and was particularly observed in cages with behaviorally abnormal parenting animals of α2δ-2/-3 cross-breedings. Juvenile α2δ-1/-2 and α2δ-2/-3 double knockout mice displayed a waddling gate similar to ducky mice. However, in contrast to ducky and α2δ-1/-3 double knockout animals, α2δ-1/-2 and α2δ-2/-3 double knockout mice showed a more severe disease progression and highly impaired development. The observed phenotypes within the individual mouse lines may be linked to differences in the volume of specific brain regions. Reduced cortical volume in ducky mice, for example, was associated with a progressively decreased space between neurons, suggesting a reduction of total synaptic connections. Taken together, our findings show that α2δ subunits differentially regulate premature survival, postnatal growth, brain development, and behavior, suggesting specific neuronal functions in health and disease.
Collapse
Affiliation(s)
- Stefanie M. Geisler
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Ariane Benedetti
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Clemens L. Schöpf
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Nadia Stefanova
- Division of Neurobiology, Department of Neurology, Medical University Innsbruck, Innsbruck, Austria
| | - Arnold Schwartz
- Department of Pharmacology and Systems Physiology, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Gerald J. Obermair
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
- Division Physiology, Karl Landsteiner University of Health Sciences, Krems an der Donau, Austria
| |
Collapse
|
6
|
Geisler S, Schöpf CL, Stanika R, Kalb M, Campiglio M, Repetto D, Traxler L, Missler M, Obermair GJ. Presynaptic α 2δ-2 Calcium Channel Subunits Regulate Postsynaptic GABA A Receptor Abundance and Axonal Wiring. J Neurosci 2019; 39:2581-2605. [PMID: 30683685 PMCID: PMC6445987 DOI: 10.1523/jneurosci.2234-18.2019] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 01/03/2019] [Accepted: 01/08/2019] [Indexed: 01/26/2023] Open
Abstract
Presynaptic α2δ subunits of voltage-gated calcium channels regulate channel abundance and are involved in glutamatergic synapse formation. However, little is known about the specific functions of the individual α2δ isoforms and their role in GABAergic synapses. Using primary neuronal cultures of embryonic mice of both sexes, we here report that presynaptic overexpression of α2δ-2 in GABAergic synapses strongly increases clustering of postsynaptic GABAARs. Strikingly, presynaptic α2δ-2 exerts the same effect in glutamatergic synapses, leading to a mismatched localization of GABAARs. This mismatching is caused by an aberrant wiring of glutamatergic presynaptic boutons with GABAergic postsynaptic positions. The trans-synaptic effect of α2δ-2 is independent of the prototypical cell-adhesion molecules α-neurexins (α-Nrxns); however, α-Nrxns together with α2δ-2 can modulate postsynaptic GABAAR abundance. Finally, exclusion of the alternatively spliced exon 23 of α2δ-2 is essential for the trans-synaptic mechanism. The novel function of α2δ-2 identified here may explain how abnormal α2δ subunit expression can cause excitatory-inhibitory imbalance often associated with neuropsychiatric disorders.SIGNIFICANCE STATEMENT Voltage-gated calcium channels regulate important neuronal functions such as synaptic transmission. α2δ subunits modulate calcium channels and are emerging as regulators of brain connectivity. However, little is known about how individual α2δ subunits contribute to synapse specificity. Here, we show that presynaptic expression of a single α2δ variant can modulate synaptic connectivity and the localization of inhibitory postsynaptic receptors. Our findings provide basic insights into the development of specific synaptic connections between nerve cells and contribute to our understanding of normal nerve cell functions. Furthermore, the identified mechanism may explain how an altered expression of calcium channel subunits can result in aberrant neuronal wiring often associated with neuropsychiatric disorders such as autism or schizophrenia.
Collapse
Affiliation(s)
- Stefanie Geisler
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Clemens L Schöpf
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Ruslan Stanika
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Marcus Kalb
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Marta Campiglio
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Daniele Repetto
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Larissa Traxler
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Gerald J Obermair
- Division of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria, and
| |
Collapse
|
7
|
Lee CA, Chin LS, Li L. Hypertonia-linked protein Trak1 functions with mitofusins to promote mitochondrial tethering and fusion. Protein Cell 2018; 9:693-716. [PMID: 28924745 PMCID: PMC6053349 DOI: 10.1007/s13238-017-0469-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 08/21/2017] [Indexed: 12/23/2022] Open
Abstract
Hypertonia is a neurological dysfunction associated with a number of central nervous system disorders, including cerebral palsy, Parkinson's disease, dystonia, and epilepsy. Genetic studies have identified a homozygous truncation mutation in Trak1 that causes hypertonia in mice. Moreover, elevated Trak1 protein expression is associated with several types of cancers and variants in Trak1 are linked to childhood absence epilepsy in humans. Despite the importance of Trak1 in health and disease, the mechanisms of Trak1 action remain unclear and the pathogenic effects of Trak1 mutation are unknown. Here we report that Trak1 has a crucial function in regulation of mitochondrial fusion. Depletion of Trak1 inhibits mitochondrial fusion, resulting in mitochondrial fragmentation, whereas overexpression of Trak1 elongates and enlarges mitochondria. Our analyses revealed that Trak1 interacts and colocalizes with mitofusins on the outer mitochondrial membrane and functions with mitofusins to promote mitochondrial tethering and fusion. Furthermore, Trak1 is required for stress-induced mitochondrial hyperfusion and pro-survival response. We found that hypertonia-associated mutation impairs Trak1 mitochondrial localization and its ability to facilitate mitochondrial tethering and fusion. Our findings uncover a novel function of Trak1 as a regulator of mitochondrial fusion and provide evidence linking dysregulated mitochondrial dynamics to hypertonia pathogenesis.
Collapse
Affiliation(s)
- Crystal A Lee
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Lih-Shen Chin
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Lian Li
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, 30322, USA.
| |
Collapse
|
8
|
Sarnat HB. Academic productivity after retirement in pediatric neurology and neuropathology. Neurology 2018; 91:36-40. [PMID: 29802168 DOI: 10.1212/wnl.0000000000005743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/20/2018] [Indexed: 12/30/2022] Open
Abstract
Many academic neurologists and neuropathologists who retire at the peak of their careers continue to be productive in research and teaching, enhanced by years of experience and mature perspective. The early 20th-century model of institutions depending upon the generosity of such individuals to donate their time and efforts without proper recognition or compensation, despite the service, prestige, and recognition they bring to their institutions, should be reconsidered in the early 21st century in the context of fairness, honesty, dignity, and increased longevity. University pensions do not distinguish retirees who continue to contribute from those who stop working. This essay represents the author's personal reflections and experience, reinforced by similar thoughts and encouragement by numerous distinguished colleagues named at the end of the text. Funding of stipends for active emeritus professors lacks precedent but should be sought.
Collapse
Affiliation(s)
- Harvey B Sarnat
- From the Departments of Paediatrics, Pathology and Laboratory Medicine (Neuropathology), and Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Canada.
| |
Collapse
|
9
|
Celli R, Santolini I, Guiducci M, van Luijtelaar G, Parisi P, Striano P, Gradini R, Battaglia G, Ngomba RT, Nicoletti F. The α2δ Subunit and Absence Epilepsy: Beyond Calcium Channels? Curr Neuropharmacol 2018; 15:918-925. [PMID: 28290248 PMCID: PMC5652034 DOI: 10.2174/1570159x15666170309105451] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/16/2017] [Accepted: 03/06/2017] [Indexed: 02/08/2023] Open
Abstract
Background: Spike-wave discharges, underlying absence seizures, are generated within a cortico-thalamo-cortical network that involves the somatosensory cortex, the reticular thalamic nucleus, and the ventrobasal thalamic nuclei. Activation of T-type voltage-sensitive calcium channels (VSCCs) contributes to the pathological oscillatory activity of this network, and some of the first-line drugs used in the treatment of absence epilepsy inhibit T-type calcium channels. The α2δ subunit is a component of high voltage-activated VSCCs (i.e., L-, N-, P/Q-, and R channels) and studies carried out in heterologous expression systems suggest that it may also associate with T channels. The α2δ subunit is also targeted by thrombospondins, which regulate synaptogenesis in the central nervous system. Objective: To discuss the potential role for the thrombospondin/α2δ axis in the pathophysiology of absence epilepsy. Methods: We searched PubMed articles for the terms “absence epilepsy”, “T-type voltage-sensitive calcium channels”, “α2δ subunit”, “ducky mice”, “pregabalin”, “gabapentin”, “thrombospondins”, and included papers focusing this Review's scope. Results: We moved from the evidence that mice lacking the α2δ-2 subunit show absence seizures and α2δ ligands (gabapentin and pregabalin) are detrimental in the treatment of absence epilepsy. This suggests that α2δ may be protective against absence epilepsy via a mechanism that does not involve T channels. We discuss the interaction between thrombospondins and α2δ and its potential relevance in the regulation of excitatory synaptic formation in the cortico-thalamo-cortical network. Conclusion: We speculate on the possibility that the thrombospondin/α2δ axis is critical for the correct functioning of the cortico-thalamo-cortical network, and that abnormalities in this axis may play a role in the pathophysiology of absence epilepsy.
Collapse
Affiliation(s)
- Roberta Celli
- I.R.C.C.S. Neuromed, Neuropharmacology Unit, Pozzilli, (IS), Italy
| | - Ines Santolini
- I.R.C.C.S. Neuromed, Neuropharmacology Unit, Pozzilli, (IS), Italy
| | - Michela Guiducci
- Departments of Neurosciences, Mental Health and Sensory Organs, Experimental Medicine, and Physiology and Pharmacology, University Sapienza, Rome, Italy
| | - Gilles van Luijtelaar
- Donders Centre for Cognition, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen. Netherlands
| | - Pasquale Parisi
- Departments of Neurosciences, Mental Health and Sensory Organs, Experimental Medicine, and Physiology and Pharmacology, University Sapienza, Rome, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, "G. Gaslini" Institute, Genova, Italy
| | - Roberto Gradini
- I.R.C.C.S. Neuromed, Neuropharmacology Unit, Pozzilli, (IS), Italy
| | | | - Richard T Ngomba
- University of Lincoln, School of Pharmacy, Lincoln, United Kingdom
| | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, University Sapienza, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| |
Collapse
|
10
|
Tiwari D, Peariso K, Gross C. MicroRNA-induced silencing in epilepsy: Opportunities and challenges for clinical application. Dev Dyn 2018; 247:94-110. [PMID: 28850760 PMCID: PMC5740004 DOI: 10.1002/dvdy.24582] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 07/20/2017] [Accepted: 08/10/2017] [Indexed: 12/25/2022] Open
Abstract
MicroRNAs are master regulators of gene expression. Single microRNAs influence multiple proteins within diverse molecular pathways and networks. Therefore, changes in levels or activity of microRNAs can have profound effects on cellular function. This makes dysregulated microRNA-induced silencing an attractive potential disease mechanism in complex disorders like epilepsy, where numerous cellular pathways and processes are affected simultaneously. Indeed, several years of research in rodent models have provided strong evidence that acute or recurrent seizures change microRNA expression and function. Moreover, altered microRNA expression has been observed in brain and blood from patients with various epilepsy disorders, such as tuberous sclerosis. MicroRNAs can be easily manipulated using sense or antisense oligonucleotides, opening up opportunities for therapeutic intervention. Here, we summarize studies using these techniques to identify microRNAs that modulate seizure susceptibility, describe protein targets mediating some of these effects, and discuss cellular pathways, for example neuroinflammation, that are controlled by epilepsy-associated microRNAs. We critically assess current gaps in knowledge regarding target- and cell-specificity of microRNAs that have to be addressed before clinical application as therapeutic targets or biomarkers. The recent progress in understanding microRNA function in epilepsy has generated strong momentum to encourage in-depth mechanistic studies to develop microRNA-targeted therapies. Developmental Dynamics 247:94-110, 2018. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Durgesh Tiwari
- Cincinnati Children’s Hospital Medical Center, Division of Neurology, Cincinnati, Ohio
| | - Katrina Peariso
- Cincinnati Children’s Hospital Medical Center, Division of Neurology, Cincinnati, Ohio
- University of Cincinnati, Department of Pediatrics, Cincinnati, Ohio
| | - Christina Gross
- Cincinnati Children’s Hospital Medical Center, Division of Neurology, Cincinnati, Ohio
- University of Cincinnati, Department of Pediatrics, Cincinnati, Ohio
| |
Collapse
|
11
|
Barel O, Malicdan MCV, Ben-Zeev B, Kandel J, Pri-Chen H, Stephen J, Castro IG, Metz J, Atawa O, Moshkovitz S, Ganelin E, Barshack I, Polak-Charcon S, Nass D, Marek-Yagel D, Amariglio N, Shalva N, Vilboux T, Ferreira C, Pode-Shakked B, Heimer G, Hoffmann C, Yardeni T, Nissenkorn A, Avivi C, Eyal E, Kol N, Glick Saar E, Wallace DC, Gahl WA, Rechavi G, Schrader M, Eckmann DM, Anikster Y. Deleterious variants in TRAK1 disrupt mitochondrial movement and cause fatal encephalopathy. Brain 2017; 140:568-581. [PMID: 28364549 PMCID: PMC6075218 DOI: 10.1093/brain/awx002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 11/22/2016] [Accepted: 12/05/2016] [Indexed: 01/12/2023] Open
Abstract
Cellular distribution and dynamics of mitochondria are regulated by several motor proteins and a microtubule network. In neurons, mitochondrial trafficking is crucial because of high energy needs and calcium ion buffering along axons to synapses during neurotransmission. The trafficking kinesin proteins (TRAKs) are well characterized for their role in lysosomal and mitochondrial trafficking in cells, especially neurons. Using whole exome sequencing, we identified homozygous truncating variants in TRAK1 (NM_001042646:c.287-2A > C), in six lethal encephalopathic patients from three unrelated families. The pathogenic variant results in aberrant splicing and significantly reduced gene expression at the RNA and protein levels. In comparison with normal cells, TRAK1-deficient fibroblasts showed irregular mitochondrial distribution, altered mitochondrial motility, reduced mitochondrial membrane potential, and diminished mitochondrial respiration. This study confirms the role of TRAK1 in mitochondrial dynamics and constitutes the first report of this gene in association with a severe neurodevelopmental disorder.
Collapse
Affiliation(s)
- Ortal Barel
- Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
| | - May Christine V Malicdan
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
- NIH Undiagnosed Diseases Program, NHGRI, National Institutes of Health, Bethesda, Maryland, USA
| | - Bruria Ben-Zeev
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Pediatric Neurology Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Tel-Hashomer, Israel
| | - Judith Kandel
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hadass Pri-Chen
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Joshi Stephen
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Inês G Castro
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Jeremy Metz
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Osama Atawa
- Palestenian Red Crescent Society Hospital, Department of Pediatrics, Hebron City, Palestine
| | - Sharon Moshkovitz
- Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
| | - Esther Ganelin
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Pediatric Neurology Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Tel-Hashomer, Israel
| | - Iris Barshack
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Department of Pathology, Sheba Medical Center, Tel-Hashomer, Israel
| | - Sylvie Polak-Charcon
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Department of Pathology, Sheba Medical Center, Tel-Hashomer, Israel
| | - Dvora Nass
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Department of Pathology, Sheba Medical Center, Tel-Hashomer, Israel
| | - Dina Marek-Yagel
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Metabolic Disease Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Tel-Hashomer, Israel
| | - Ninette Amariglio
- Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
| | - Nechama Shalva
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Metabolic Disease Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Tel-Hashomer, Israel
| | - Thierry Vilboux
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
- Inova Translational Medicine Institute, Inova Health System, Falls Church, Virginia, USA
| | - Carlos Ferreira
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
- Division of Genetics and Metabolism, Children’s National Health System, Washington DC, USA
| | - Ben Pode-Shakked
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Metabolic Disease Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Tel-Hashomer, Israel
- The Dr. Pinchas Borenstein Talpiot Medical Leadership Program, Sheba Medical Center, Tel-Hashomer, Israel
| | - Gali Heimer
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Pediatric Neurology Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Tel-Hashomer, Israel
- The Dr. Pinchas Borenstein Talpiot Medical Leadership Program, Sheba Medical Center, Tel-Hashomer, Israel
| | - Chen Hoffmann
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Department of Radiology, Sheba Medical Center, Tel-Hashomer, Israel
| | - Tal Yardeni
- Center for Mitochondrial and Epigenomic Medicine, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Andreea Nissenkorn
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Service for Rare Disorders, Pediatric Neurology Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Tel-Hashomer, Israel
| | - Camila Avivi
- Department of Pathology, Sheba Medical Center, Tel-Hashomer, Israel
| | - Eran Eyal
- Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
| | - Nitzan Kol
- Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
| | - Efrat Glick Saar
- Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
| | - Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - William A Gahl
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
- NIH Undiagnosed Diseases Program, NHGRI, National Institutes of Health, Bethesda, Maryland, USA
| | - Gideon Rechavi
- Sheba Cancer Research Center, Sheba Medical Center, Tel-Hashomer, Israel
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Michael Schrader
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - David M Eckmann
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yair Anikster
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Metabolic Disease Unit, Edmond and Lily Safra Children’s Hospital, Sheba Medical Center, Tel-Hashomer, Israel
| |
Collapse
|
12
|
Geisler S, Schöpf CL, Obermair GJ. Emerging evidence for specific neuronal functions of auxiliary calcium channel α₂δ subunits. Gen Physiol Biophys 2014; 34:105-118. [PMID: 25504062 DOI: 10.4149/gpb_2014037] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 11/06/2014] [Indexed: 11/08/2022]
Abstract
In nerve cells the ubiquitous second messenger calcium regulates a variety of vitally important functions including neurotransmitter release, gene regulation, and neuronal plasticity. The entry of calcium into cells is tightly regulated by voltage-gated calcium channels, which consist of a heteromultimeric complex of a pore forming α₁, and the auxiliary β and α₂δ subunits. Four genes (Cacna2d1-4) encode for the extracellular membrane-attached α₂δ subunits (α₂δ-1 to α₂δ-4), out of which three isoforms (α₂δ-1 to -3) are strongly expressed in the central nervous system. Over the years a wealth of studies has demonstrated the classical role of α₂δ subunits in channel trafficking and calcium current modulation. Recent studies in specialized neuronal cell systems propose roles of α₂δ subunits beyond the classical view and implicate α₂δ subunits as important regulators of synapse formation. These findings are supported by the identification of novel human disease mutations associated with α₂δ subunits and by the fact that α₂δ subunits are the target of the anti-epileptic and anti-allodynic drugs gabapentin and pregabalin. Here we review the recently emerging evidence for specific as well as redundant neuronal roles of α₂δ subunits and discuss the mechanisms for establishing and maintaining specificity.
Collapse
Affiliation(s)
- Stefanie Geisler
- Division of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Clemens L Schöpf
- Division of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Gerald J Obermair
- Division of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, 6020 Innsbruck, Austria
| |
Collapse
|
13
|
Tan CL, Plotkin JL, Venø MT, von Schimmelmann M, Feinberg P, Mann S, Handler A, Kjems J, Surmeier DJ, O'Carroll D, Greengard P, Schaefer A. MicroRNA-128 governs neuronal excitability and motor behavior in mice. Science 2013; 342:1254-8. [PMID: 24311694 DOI: 10.1126/science.1244193] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The control of motor behavior in animals and humans requires constant adaptation of neuronal networks to signals of various types and strengths. We found that microRNA-128 (miR-128), which is expressed in adult neurons, regulates motor behavior by modulating neuronal signaling networks and excitability. miR-128 governs motor activity by suppressing the expression of various ion channels and signaling components of the extracellular signal-regulated kinase ERK2 network that regulate neuronal excitability. In mice, a reduction of miR-128 expression in postnatal neurons causes increased motor activity and fatal epilepsy. Overexpression of miR-128 attenuates neuronal responsiveness, suppresses motor activity, and alleviates motor abnormalities associated with Parkinson's-like disease and seizures in mice. These data suggest a therapeutic potential for miR-128 in the treatment of epilepsy and movement disorders.
Collapse
Affiliation(s)
- Chan Lek Tan
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10065, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Revisiting the TRAK family of proteins as mediators of GABAA receptor trafficking. Neurochem Res 2013; 39:992-6. [PMID: 24122114 DOI: 10.1007/s11064-013-1170-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/26/2013] [Accepted: 10/01/2013] [Indexed: 10/26/2022]
Abstract
γ-Aminobutyric acid type A (GABAA) receptor interacting factor-1 (GRIF-1) was originally discovered as a result of studies aiming to find the elusive GABAA receptor clustering protein. It was identified as a GABAA receptor associated protein by virtue of its specific interaction with the GABAA receptor β2 subunit intracellular loop in a yeast two-hybrid screen of a rat brain cDNA library. Further work however, established that GRIF-1, now known as trafficking kinesin protein 2 (TRAK2), is a member of the TRAK family of kinesin adaptor proteins. A pivotal role for TRAK1 and TRAK2 in the transport of mitochondria is well recognized. Notwithstanding this progress, there is a body of evidence that still supports a role for TRAKs in the intracellular transport of GABAA receptors. This is critically reviewed in this article.
Collapse
|
15
|
Boonpeng H, Yusoff K. The utility of copy number variation (CNV) in studies of hypertension-related left ventricular hypertrophy (LVH): rationale, potential and challenges. Mol Cytogenet 2013; 6:8. [PMID: 23448375 PMCID: PMC3599593 DOI: 10.1186/1755-8166-6-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 01/03/2013] [Indexed: 01/08/2023] Open
Abstract
The ultimate goal of human genetics is to understand the role of genome variation in elucidating human traits and diseases. Besides single nucleotide polymorphism (SNP), copy number variation (CNV), defined as gains or losses of a DNA segment larger than 1 kb, has recently emerged as an important tool in understanding heritable source of human genomic differences. It has been shown to contribute to genetic susceptibility of various common and complex diseases. Despite a handful of publications, its role in cardiovascular diseases remains largely unknown. Here, we deliberate on the currently available technologies for CNV detection. The possible utility and the potential roles of CNV in exploring the mechanisms of cardiac remodeling in hypertension will also be addressed. Finally, we discuss the challenges for investigations of CNV in cardiovascular diseases and its possible implications in diagnosis of hypertension-related left ventricular hypertrophy (LVH).
Collapse
Affiliation(s)
- Hoh Boonpeng
- Institute of Medical Molecular Biotechnology, Faculty of Medicine, Universiti Teknologi MARA, Sungai Buloh Campus, Jalan Hospital, Sungai, Buloh, 47000, Malaysia.
| | | |
Collapse
|
16
|
Abstract
One of the most exciting areas in epilepsy has been the explosion in our understanding of the genetics of the epilepsies over the last decade. Built on a long history of careful clinical genetic studies of the epilepsies, the relatively recent discovery of epilepsy genes has enabled insights into pathways causing seizure disorders. A variety of mutational mechanisms can cause epilepsy resulting from different, and sometimes surprising, molecular processes such as copy number variation within the genome. The majority of known epilepsy genes encode ion channel subunits leading many of the genetic epilepsies to be regarded as channelopathies. Understanding how dysfunction of a mutant protein leads to hyperexcitability is key to understanding the pathophysiology of this group of serious and common childhood disorders. The architecture of the common genetic epilepsies following complex inheritance, where multiple genes are involved, is also beginning to be unraveled. The clinical approach to understanding the genetics of the epilepsies has matured and requires a detailed family history of seizures together with delineation of the child's epilepsy syndrome. Recognition of specific genetic epilepsy syndromes enables optimal treatment and prognostic and genetic counseling.
Collapse
Affiliation(s)
- Rima Nabbout
- Department of Pediatric Neurology, Hôpital Necker-Enfants Malades; Centre de référence épilepsies rares; INSERM U663, Paris, France.
| | | |
Collapse
|
17
|
Michelucci R, Pasini E, Riguzzi P, Volpi L, Dazzo E, Nobile C. Genetics of epilepsy and relevance to current practice. Curr Neurol Neurosci Rep 2012; 12:445-55. [PMID: 22618127 DOI: 10.1007/s11910-012-0281-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Genetic factors are likely to play a major role in many epileptic conditions, spanning from classical idiopathic (genetic) generalized epilepsies to epileptic encephalopathies and focal epilepsies. In this review we describe the genetic advances in progressive myoclonus epilepsies, which are strictly monogenic disorders, genetic generalized epilepsies, mostly exhibiting complex genetic inheritance, and SCN1A-related phenotypes, namely genetic generalized epilepsy with febrile seizure plus and Dravet syndrome. Particular attention is devoted to a form of familial focal epilepsies, autosomal-dominant lateral temporal epilepsy, which is a model of non-ion genetic epilepsies. This condition is associated with mutations of the LGI1 gene, whose protein is secreted from the neurons and exerts its action on a number of targets, influencing cortical development and neuronal maturation.
Collapse
Affiliation(s)
- Roberto Michelucci
- Unit of Neurology, IRCCS Institute of Neurological Sciences, Bellaria Hospital, Via Altura 3, 40139, Bologna, Italy.
| | | | | | | | | | | |
Collapse
|
18
|
Abstract
Current and emerging technologies for mutation identification are changing the landscape of genetics and accelerating the pace of discovery. Application of high throughput genomic analysis to epilepsy will advance our understanding of the genetic contribution to common forms of epilepsy and suggest novel therapeutic strategies for improved treatment.
Collapse
|
19
|
Fernández AI, Pérez-Montarelo D, Barragán C, Ramayo-Caldas Y, Ibáñez-Escriche N, Castelló A, Noguera JL, Silió L, Folch JM, Rodríguez MC. Genome-wide linkage analysis of QTL for growth and body composition employing the PorcineSNP60 BeadChip. BMC Genet 2012; 13:41. [PMID: 22607048 PMCID: PMC3432624 DOI: 10.1186/1471-2156-13-41] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 04/30/2012] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND The traditional strategy to map QTL is to use linkage analysis employing a limited number of markers. These analyses report wide QTL confidence intervals, making very difficult to identify the gene and polymorphisms underlying the QTL effects. The arrival of genome-wide panels of SNPs makes available thousands of markers increasing the information content and therefore the likelihood of detecting and fine mapping QTL regions. The aims of the current study are to confirm previous QTL regions for growth and body composition traits in different generations of an Iberian x Landrace intercross (IBMAP) and especially identify new ones with narrow confidence intervals by employing the PorcineSNP60 BeadChip in linkage analyses. RESULTS Three generations (F3, Backcross 1 and Backcross 2) of the IBMAP and their related animals were genotyped with PorcineSNP60 BeadChip. A total of 8,417 SNPs equidistantly distributed across autosomes were selected after filtering by quality, position and frequency to perform the QTL scan. The joint and separate analyses of the different IBMAP generations allowed confirming QTL regions previously identified in chromosomes 4 and 6 as well as new ones mainly for backfat thickness in chromosomes 4, 5, 11, 14 and 17 and shoulder weight in chromosomes 1, 2, 9 and 13; and many other to the chromosome-wide signification level. In addition, most of the detected QTLs displayed narrow confidence intervals, making easier the selection of positional candidate genes. CONCLUSIONS The use of higher density of markers has allowed to confirm results obtained in previous QTL scans carried out with microsatellites. Moreover several new QTL regions have been now identified in regions probably not covered by markers in previous scans, most of these QTLs displayed narrow confidence intervals. Finally, prominent putative biological and positional candidate genes underlying those QTL effects are listed based on recent porcine genome annotation.
Collapse
Affiliation(s)
- Ana I Fernández
- Departamento de Mejora Genética Animal, INIA, Ctra, De la Coruña km, 7, Madrid, 28040, Spain.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Leu C, de Kovel CGF, Zara F, Striano P, Pezzella M, Robbiano A, Bianchi A, Bisulli F, Coppola A, Giallonardo AT, Beccaria F, Trenité DKN, Lindhout D, Gaus V, Schmitz B, Janz D, Weber YG, Becker F, Lerche H, Kleefuss-Lie AA, Hallman K, Kunz WS, Elger CE, Muhle H, Stephani U, Møller RS, Hjalgrim H, Mullen S, Scheffer IE, Berkovic SF, Everett KV, Gardiner MR, Marini C, Guerrini R, Lehesjoki AE, Siren A, Nabbout R, Baulac S, Leguern E, Serratosa JM, Rosenow F, Feucht M, Unterberger I, Covanis A, Suls A, Weckhuysen S, Kaneva R, Caglayan H, Turkdogan D, Baykan B, Bebek N, Ozbek U, Hempelmann A, Schulz H, Rüschendorf F, Trucks H, Nürnberg P, Avanzini G, Koeleman BPC, Sander T. Genome-wide linkage meta-analysis identifies susceptibility loci at 2q34 and 13q31.3 for genetic generalized epilepsies. Epilepsia 2012; 53:308-18. [PMID: 22242659 DOI: 10.1111/j.1528-1167.2011.03379.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
PURPOSE Genetic generalized epilepsies (GGEs) have a lifetime prevalence of 0.3% with heritability estimates of 80%. A considerable proportion of families with siblings affected by GGEs presumably display an oligogenic inheritance. The present genome-wide linkage meta-analysis aimed to map: (1) susceptibility loci shared by a broad spectrum of GGEs, and (2) seizure type-related genetic factors preferentially predisposing to either typical absence or myoclonic seizures, respectively. METHODS Meta-analysis of three genome-wide linkage datasets was carried out in 379 GGE-multiplex families of European ancestry including 982 relatives with GGEs. To dissect out seizure type-related susceptibility genes, two family subgroups were stratified comprising 235 families with predominantly genetic absence epilepsies (GAEs) and 118 families with an aggregation of juvenile myoclonic epilepsy (JME). To map shared and seizure type-related susceptibility loci, both nonparametric loci (NPL) and parametric linkage analyses were performed for a broad trait model (GGEs) in the entire set of GGE-multiplex families and a narrow trait model (typical absence or myoclonic seizures) in the subgroups of JME and GAE families. KEY FINDINGS For the entire set of 379 GGE-multiplex families, linkage analysis revealed six loci achieving suggestive evidence for linkage at 1p36.22, 3p14.2, 5q34, 13q12.12, 13q31.3, and 19q13.42. The linkage finding at 5q34 was consistently supported by both NPL and parametric linkage results across all three family groups. A genome-wide significant nonparametric logarithm of odds score of 3.43 was obtained at 2q34 in 118 JME families. Significant parametric linkage to 13q31.3 was found in 235 GAE families assuming recessive inheritance (heterogeneity logarithm of odds = 5.02). SIGNIFICANCE Our linkage results support an oligogenic predisposition of familial GGE syndromes. The genetic risk factor at 5q34 confers risk to a broad spectrum of familial GGE syndromes, whereas susceptibility loci at 2q34 and 13q31.3 preferentially predispose to myoclonic seizures or absence seizures, respectively. Phenotype- genotype strategies applying narrow trait definitions in phenotypic homogeneous subgroups of families improve the prospects of disentangling the genetic basis of common familial GGE syndromes.
Collapse
|
21
|
Kao A, Rao PM. Idiopathic generalized epilepsies. HANDBOOK OF CLINICAL NEUROLOGY 2012; 107:209-224. [PMID: 22938973 DOI: 10.1016/b978-0-444-52898-8.00013-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Affiliation(s)
- Amy Kao
- Center for Neuroscience and Behavioral Medicine, Children's National Medical Center, Washington, DC, USA.
| | | |
Collapse
|
22
|
Blair MA, Abou-Khalil B, Crunk A, Haines JL, Hedera P. A new locus for autosomal dominant generalized epilepsy associated with mild mental retardation on chromosome 3p. Epilepsia 2011; 52:993-9. [PMID: 21480884 DOI: 10.1111/j.1528-1167.2011.03059.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE Generalized epilepsies are clinically and genetically heterogeneous syndromes. Idiopathic generalized epilepsy (IGE), which has a strong genetic background, is not associated with any additional clinical features, such as mental retardation (MR). Herein we report results of linkage analysis in a large family with autosomal dominant (AD) generalized epilepsy associated with MR. METHODS We identified a four-generation kindred with several affected members with generalized epilepsy without any evidence for secondary causes. Electroencephalography (EEG) studies and magnetic resonance imaging (MRI) results were reviewed when available. We performed a genome-wide linkage analysis. KEY FINDINGS Fourteen individuals were classified as affected and an additional three were considered as nonpenetrant obligatory carriers. Thirteen affected individual had a history of generalized tonic-clonic seizures, and absence seizures were reported in nine affected individuals. There was no history of preceding febrile seizures. MR was present in nine affected individuals with epilepsy but the other affected individuals had normal intelligence. Neuroimaging did not reveal any structural abnormalities and EEG studies were consistent with IGE rather than symptomatic generalized epilepsy. Genetic analysis detected a group of markers with logarithmic (base 10) of odds (LOD) score >3 on chromosome 3p spanning a 5.5 Mbp region. Sequencing of several candidate genes, including dynein light chain-A, golgin subfamily a4, leucine rich repeat (in FLII) interacting gene, serine/threonine-protein kinase DCAMKL3 (doublecortin- like and CAM kinase-like 3), laforin (EPM2A) interacting protein 1 (EPM2AIP1, programmed cell death 6 interacting protein, and CLIP-associating protein 2 (cytoplasmic linker-associated protein 2) (hOrbit2) genes did not identify the disease-causing mutations. SIGNIFICANCE We report the identification of a genetic locus for generalized epilepsy associated with MR on chromosome 3p. Affected individuals have a form of genetic epilepsy with generalized seizures variably associated with MR. Despite the presence of MR in several affected patients, epilepsy phenotype was not fully consistent with symptomatic epilepsy and suggests a biologic continuum between symptomatic epilepsies and IGE.
Collapse
Affiliation(s)
- Marcia A Blair
- Department of Neurology, Vanderbilt University, Nashville, Tennessee 37232- 8552, USA
| | | | | | | | | |
Collapse
|
23
|
Yalçin O, Baykan B, Ağan K, Yapici Z, Yalçin D, Dizdarer G, Türkdoğan D, Ozkara C, Unalp A, Uludüz D, Gül G, Kuşcu D, Ayta S, Tutkavul K, Comu S, Tatli B, Meral C, Bebek N, Cağlayan SH. An association analysis at 2q36 reveals a new candidate susceptibility gene for juvenile absence epilepsy and/or absence seizures associated with generalized tonic-clonic seizures. Epilepsia 2011; 52:975-83. [PMID: 21320115 DOI: 10.1111/j.1528-1167.2010.02970.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE To further evaluate the previously shown linkage of absence epilepsy (AE) to 2q36, both in human and WAG/Rij absence rat models, a 160-kb region at 2q36 containing eight genes with expressions in the brain was targeted in a case-control association study involving 205 Turkish patients with AE and 219 controls. METHODS Haplotype block and case-control association analysis was carried out using HAPLOVIEW 4.0 and inhibin alpha subunit (INHA) gene analysis by DNA sequencing. KEY FINDINGS An association was found between the G allele of rs7588807 located in the INHA gene and juvenile absence epilepsy (JAE) syndrome and patients having generalized tonic-clonic seizures (GTCS) with p-values of 0.003 and 0.0002, respectively (uncorrected for multiple comparisons). DNA sequence analysis of the INHA gene in 110 JAE/GTCS patients revealed three point mutations with possible damaging effects on inhibin function in three patients and the presence of a common ACTC haplotype (H1) with a possible dominant protective role conferred by the T allele of rs7588807 with respective p-values of 0.0005 and 0.0014. SIGNIFICANCE The preceding findings suggest that INHA could be a novel candidate susceptibility gene involved in the pathogenesis of JAE or AE associated with GTCS.
Collapse
Affiliation(s)
- Ozlem Yalçin
- Molecular Biology and Genetics, Boğaziçi University, Istanbul, Turkey
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Li Q, Li X, Zhang F, Chen F. The Identification of a Novel Locus for Mandibular Prognathism in the Han Chinese Population. J Dent Res 2010; 90:53-7. [DOI: 10.1177/0022034510382546] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Mandibular prognathism is a common dentofacial phenotype with a substantial genetic component; however, few susceptibility loci have been mapped. Ethnicity is a risk factor for mandibular prognathism, and a relatively high prevalence is observed in Asian populations. The hypothesis of this study suggested that a specific locus for mandibular prognathism exists in the Han Chinese population. So, the authors studied a Han Chinese pedigree in which mandibular prognathism was inherited (11 affected, 10 unaffected) in an autosomal dominant pattern. A genomewide linkage scan was performed with the Illumina Linkage-12 DNA Analysis Kit. Multipoint parametric and nonparametric linkage analyses were performed with MERLIN 1.01. A susceptibility locus was identified on chromosome 14q24.3-31.2, with a nonparametric linkage score of 11.341 (empirical P = .020) and a logarithm of the odds score of 2.032 (empirical P = .008). Haplotype analysis refined the candidate locus to a 10.62-cM interval (72.42 to 83.14 cM; 74.57 to 84.66 Mb) between rs1468507 and rs7141857. Within this interval, the candidate functional genes are TGFB3 and LTBP2. In conclusion, the authors detected a suggestive linkage for mandibular prognathism in a Han Chinese pedigree, and this finding can be combined with previous studies to further understand the genetic basis of mandibular prognathism.
Collapse
Affiliation(s)
- Q. Li
- Department of Orthodontics, Dental School, Tongji University, Shanghai, People’s Republic of China
| | - X. Li
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - F. Zhang
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, People’s Republic of China
| | - F. Chen
- Department of Orthodontics, Dental School, Tongji University, Shanghai, People’s Republic of China
| |
Collapse
|
25
|
Abstract
Many specifically human psychiatric and neurological conditions have developmental origins. Rodent models are extremely valuable for the investigation of brain development, but cannot provide insight into aspects that are specifically human. The human brain, and particularly the cerebral cortex, has some unique genetic, molecular, cellular and anatomical features, and these need to be further explored. Cortical expansion in human is not just quantitative; there are some novel types of neurons and cytoarchitectonic areas identified by their gene expression, connectivity and functions that do not exist in rodents. Recent research into human brain development has revealed more elaborated neurogenetic compartments, radial and tangential migration, transient cell layers in the subplate, and a greater diversity of early-generated neurons, including predecessor neurons. Recently there has been a renaissance of the study of human brain development because of these unique differences, made possible by the availability of new techniques. This review gives a flavour of the recent studies stemming from this renewed focus on the developing human brain.
Collapse
Affiliation(s)
- Gavin Clowry
- Institute of Neuroscience, Newcastle UniversityNewcastle upon Tyne, UK
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
| | - Pasko Rakic
- Department of Neurobiology, Kavli Institute of Neuroscience, Yale University School of MedicineNew Haven, CT, USA
| |
Collapse
|