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Current Pharmacologic Strategies for Treatment of Intractable Epilepsy in Children. Int Neurourol J 2021; 25:S8-18. [PMID: 34053206 PMCID: PMC8171244 DOI: 10.5213/inj.2142166.083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 05/02/2021] [Indexed: 11/26/2022] Open
Abstract
Epileptic encephalopathy (EE) is a devastating pediatric disease that features medically resistant seizures, which can contribute to global developmental delays. Despite technological advancements in genetics, the neurobiological mechanisms of EEs are not fully understood, leaving few therapeutic options for affected patients. In this review, we introduce the most common EEs in pediatrics (i.e., Ohtahara syndrome, Dravet syndrome, and Lennox-Gastaut syndrome) and their molecular mechanisms that cause excitation/inhibition imbalances. We then discuss some of the essential molecules that are frequently dysregulated in EEs. Specifically, we explore voltage-gated ion channels, synaptic transmission-related proteins, and ligand-gated ion channels in association with the pathophysiology of Ohtahara syndrome, Dravet syndrome, and Lennox-Gastaut syndrome. Finally, we review currently available antiepileptic drugs used to treat seizures in patients with EEs. Since these patients often fail to achieve seizure relief even with the combination therapy, further extensive research efforts to explore the involved molecular mechanisms will be required to develop new drugs for patients with intractable epilepsy.
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Pandya NJ, Seeger C, Babai N, Gonzalez-Lozano MA, Mack V, Lodder JC, Gouwenberg Y, Mansvelder HD, Danielson UH, Li KW, Heine M, Spijker S, Frischknecht R, Smit AB. Noelin1 Affects Lateral Mobility of Synaptic AMPA Receptors. Cell Rep 2019; 24:1218-1230. [PMID: 30067977 PMCID: PMC6088136 DOI: 10.1016/j.celrep.2018.06.102] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 04/26/2018] [Accepted: 06/26/2018] [Indexed: 11/24/2022] Open
Abstract
Lateral diffusion on the neuronal plasma membrane of the AMPA-type glutamate receptor (AMPAR) serves an important role in synaptic plasticity. We investigated the role of the secreted glycoprotein Noelin1 (Olfactomedin-1 or Pancortin) in AMPAR lateral mobility and its dependence on the extracellular matrix (ECM). We found that Noelin1 interacts with the AMPAR with high affinity, however, without affecting rise- and decay time and desensitization properties. Noelin1 co-localizes with synaptic and extra-synaptic AMPARs and is expressed at synapses in an activity-dependent manner. Single-particle tracking shows that Noelin1 reduces lateral mobility of both synaptic and extra-synaptic GluA1-containing receptors and affects short-term plasticity. While the ECM does not constrain the synaptic pool of AMPARs and acts only extrasynaptically, Noelin1 contributes to synaptic potentiation by limiting AMPAR mobility at synaptic sites. This is the first evidence for the role of a secreted AMPAR-interacting protein on mobility of GluA1-containing receptors and synaptic plasticity. Noelin1 interacts with high affinity to AMPA receptors (AMPARs) Noelin1 is secreted upon cellular stimulation (Extra)synaptic AMPAR mobility, but not channel properties, are affected by Noelin1 Reducing synaptic AMPAR lateral mobility by Noelin1 limits synaptic plasticity
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Affiliation(s)
- Nikhil J Pandya
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
| | - Christian Seeger
- Beactica AB, Virdings allé 2, 754 50 Uppsala, Sweden; Department of Chemistry - BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
| | - Norbert Babai
- Department of Biology, Animal Physiology, Friedrich Alexander University Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Miguel A Gonzalez-Lozano
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
| | - Volker Mack
- Department of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH and Co. KG, Biberach (an der Riss), Germany
| | - Johannes C Lodder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
| | - Yvonne Gouwenberg
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
| | - U Helena Danielson
- Beactica AB, Virdings allé 2, 754 50 Uppsala, Sweden; Department of Chemistry - BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
| | - Ka Wan Li
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands
| | - Martin Heine
- Research Group Molecular Physiology, Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany
| | - Sabine Spijker
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands.
| | - Renato Frischknecht
- Department of Biology, Animal Physiology, Friedrich Alexander University Erlangen-Nürnberg, 91058 Erlangen, Germany; Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands.
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Transgenic overexpression of furin increases epileptic susceptibility. Cell Death Dis 2018; 9:1058. [PMID: 30333479 PMCID: PMC6193048 DOI: 10.1038/s41419-018-1076-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 09/01/2018] [Accepted: 09/07/2018] [Indexed: 11/28/2022]
Abstract
The proprotein convertase Furin plays crucial roles in the pathology of many diseases. However, the specific role of furin in epilepsy remains unclear. In our study, furin protein was increased in the temporal neocortex of epileptic patients and in the hippocampus and cortex of epileptic mice. The furin transgenic (TG) mice showed increased susceptibility to epilepsy and heightened epileptic activity compared with wild-type (WT) mice. Conversely, lentivirus-mediated knockdown of furin restrained epileptic activity. Using whole-cell patch clamp, furin knockdown and overexpression influenced neuronal inhibitory by regulating postsynaptic gamma-aminobutyric acid A receptor (GABAAR)-mediated synaptic transmission. Importantly, furin influenced the expression of GABAAR β2/3 membrane and total protein in epileptic mice by changing transcription level of GABAAR β2/3, not the protein degradation. These results reveal that furin may regulate GABAAR-mediated inhibitory synaptic transmission by altering the transcription of GABAAR β2/3 subunits in epilepsy; this finding could provide new insight into epilepsy prevention and treatment.
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Abstract
UNLABELLED Synapses depend on trafficking of key membrane proteins by lateral diffusion from surface populations and by exocytosis from intracellular pools. The cell adhesion molecule neurexin (Nrxn) plays essential roles in synapses, but the dynamics and regulation of its trafficking are unknown. Here, we performed single-particle tracking and live imaging of transfected, epitope-tagged Nrxn variants in cultured rat and mouse wild-type or knock-out neurons. We observed that structurally larger αNrxn molecules are more mobile in the plasma membrane than smaller βNrxns because αNrxns displayed higher diffusion coefficients in extrasynaptic regions and excitatory or inhibitory terminals. We found that well characterized interactions with extracellular binding partners regulate the surface mobility of Nrxns. Binding to neurexophilin-1 (Nxph1) reduced the surface diffusion of αNrxns when both molecules were coexpressed. Conversely, impeding other interactions by insertion of splice sequence #4 or removal of extracellular Ca(2+) augmented the mobility of αNrxns and βNrxns. We also determined that fast axonal transport delivers Nrxns to the neuronal surface because Nrxns comigrate as cargo on synaptic vesicle protein transport vesicles (STVs). Unlike surface mobility, intracellular transport of βNrxn(+) STVs was faster than that of αNrxns, but both depended on the microtubule motor protein KIF1A and neuronal activity regulated the velocity. Large spontaneous fusion of Nrxn(+) STVs occurred simultaneously with synaptophysin on axonal membranes mostly outside of active presynaptic terminals. Surface Nrxns enriched at synaptic terminals where αNrxns and Nxph1/αNrxns recruited GABAAR subunits. Therefore, our results identify regulated dynamic trafficking as an important property of Nrxns that corroborates their function at synapses. SIGNIFICANCE STATEMENT Synapses mediate most functions in our brains and depend on the precise and timely delivery of key molecules throughout life. Neurexins (Nrxns) are essential synaptic cell adhesion molecules that are involved in synaptic transmission and differentiation of synaptic contacts. In addition, Nrxns have been linked to neuropsychiatric diseases such as autism. Because little is known about the dynamic aspects of trafficking of neurexins to synapses, we investigated this important question using single-molecule tracking and time-lapse imaging. We identify distinct differences between major Nrxn variants both in surface mobility and during intracellular transport. Because their dynamic behavior is highly regulated, for example, by different binding activities, these processes have immediate consequences for the function of Nrxns at synapses.
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The Nanoscale Observation of the Three-Dimensional Structures of Neurosynapses, Membranous Conjunctions Between Cultured Hippocampal Neurons and Their Significance in the Development of Epilepsy. Mol Neurobiol 2015; 53:7137-7157. [DOI: 10.1007/s12035-015-9588-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/29/2015] [Indexed: 12/11/2022]
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Vasil’ev AN, Kulish AV. Influence of mediator diffusion on trigger mode of a synapse. Biophysics (Nagoya-shi) 2014. [DOI: 10.1134/s0006350914020262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Karataeva AR, Klaassen RV, Ströder J, Ruiperez-Alonso M, Hjorth JJJ, van Nierop P, Spijker S, Mansvelder HD, Smit AB. C-terminal interactors of the AMPA receptor auxiliary subunit Shisa9. PLoS One 2014; 9:e87360. [PMID: 24498314 PMCID: PMC3911953 DOI: 10.1371/journal.pone.0087360] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 12/23/2013] [Indexed: 01/01/2023] Open
Abstract
Shisa9 (initially named CKAMP44) has been identified as auxiliary subunit of the AMPA-type glutamate receptors and was shown to modulate its physiological properties. Shisa9 is a type-I transmembrane protein and contains a C-terminal PDZ domain that potentially interacts with cytosolic proteins. In this study, we performed a yeast two-hybrid screening that yielded eight PDZ domain-containing interactors of Shisa9, which were independently validated. The identified interactors are known scaffolding proteins residing in the neuronal postsynaptic density. To test whether C-terminal scaffolding interactions of Shisa9 affect synaptic AMPA receptor function in the hippocampus, we disrupted these interactions using a Shisa9 C-terminal mimetic peptide. In the absence of scaffolding interactions of Shisa9, glutamatergic AMPA receptor-mediated synaptic currents in the lateral perforant path of the mouse hippocampus had a faster decay time, and paired-pulse facilitation was reduced. Furthermore, disruption of the PDZ interactions between Shisa9 and its binding partners affected hippocampal network activity. Taken together, our data identifies novel interaction partners of Shisa9, and shows that the C-terminal interactions of Shisa9 through its PDZ domain interaction motif are important for AMPA receptor synaptic and network functions.
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Affiliation(s)
- Anna R. Karataeva
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit University, Amsterdam, The Netherlands
| | - Remco V. Klaassen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit University, Amsterdam, The Netherlands
| | - Jasper Ströder
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit University, Amsterdam, The Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit University, Amsterdam, The Netherlands
| | - Marta Ruiperez-Alonso
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit University, Amsterdam, The Netherlands
| | - Johannes J. J. Hjorth
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit University, Amsterdam, The Netherlands
| | - Pim van Nierop
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit University, Amsterdam, The Netherlands
| | - Sabine Spijker
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit University, Amsterdam, The Netherlands
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit University, Amsterdam, The Netherlands
| | - August B. Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit University, Amsterdam, The Netherlands
- * E-mail:
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Casillas-Espinosa PM, Powell KL, O'Brien TJ. Regulators of synaptic transmission: roles in the pathogenesis and treatment of epilepsy. Epilepsia 2013; 53 Suppl 9:41-58. [PMID: 23216578 DOI: 10.1111/epi.12034] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Synaptic transmission is the communication between a presynaptic and a postsynaptic neuron, and the subsequent processing of the signal. These processes are complex and highly regulated, reflecting their importance in normal brain functioning and homeostasis. Sustaining synaptic transmission depends on the continuing cycle of synaptic vesicle formation, release, and endocytosis, which requires proteins such as dynamin, syndapin, synapsin, and synaptic vesicle protein 2A. Synaptic transmission is regulated by diverse mechanisms, including presynaptic modulators of synaptic vesicle formation and release, postsynaptic receptors and signaling, and modulators of neurotransmission. Neurotransmitters released presynaptically can bind to their postsynaptic receptors, the inhibitory γ-aminobutyric acid (GABA)ergic receptors or the excitatory glutamate receptors. Once released, glutamate activates a variety of postsynaptic receptors including α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), N-methyl-D-aspartate (NMDA), kainate, and metabotropic receptors. The activation of the receptors triggers downstream signaling cascades generating a vast array of effects, which can be modulated by a numerous auxiliary regulatory subunits. Moreover, different neuropeptides such as neuropeptide Y, brain-derived neurotrophic factor (BDNF), somatostatin, ghrelin, and galanin, act as regulators of diverse synaptic functions and along with the classic neurotransmitters. Abnormalities in the regulation of synaptic transmission play a critical role in the pathogenesis of numerous brain diseases, including epilepsy. This review focuses on the different mechanisms involved in the regulation of synaptic transmission, which may play a role in the pathogenesis of epilepsy: the presynaptic modulators of synaptic vesicle formation and release, postsynaptic receptors, and modulators of neurotransmission, including the mechanism by which drugs can modulate the frequency and severity of epileptic seizures.
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Affiliation(s)
- Pablo M Casillas-Espinosa
- The Departments of Medicine and Neurology, The Royal Melbourne Hospital, The Melbourne Brain Centre, The University of Melbourne, Parkville, Victoria, Australia
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