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Li S, Guo Y, Takahashi M, Suzuki H, Kosaki K, Ohshima T. Forebrain commissure formation in zebrafish embryo requires the binding of KLC1 to CRMP2. Dev Neurobiol 2024; 84:203-216. [PMID: 38830696 DOI: 10.1002/dneu.22948] [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: 01/25/2024] [Revised: 05/17/2024] [Accepted: 05/18/2024] [Indexed: 06/05/2024]
Abstract
Formation of the corpus callosum (CC), anterior commissure (AC), and postoptic commissure (POC), connecting the left and right cerebral hemispheres, is crucial for cerebral functioning. Collapsin response mediator protein 2 (CRMP2) has been suggested to be associated with the mechanisms governing this formation, based on knockout studies in mice and knockdown/knockout studies in zebrafish. Previously, we reported two cases of non-synonymous CRMP2 variants with S14R and R565C substitutions. Among the, the R565C substitution (p.R565C) was caused by the novel CRMP2 mutation c.1693C > T, and the patient presented with intellectual disability accompanied by CC hypoplasia. In this study, we demonstrate that crmp2 mRNA could rescue AC and POC formation in crmp2-knockdown zebrafish, whereas the mRNA with the R566C mutation could not. Zebrafish CRMP2 R566C corresponds to human CRMP2 R565C. Further experiments with transfected cultured cells indicated that CRMP2 with the R566C mutation could not bind to kinesin light chain 1 (KLC1). Knockdown of klc1a in zebrafish resulted in defective AC and POC formation, revealing a genetic interaction with crmp2. These findings suggest that the CRMP2 R566C mutant fails to bind to KLC1, preventing axonal elongation and leading to defective AC and POC formation in zebrafish and CC formation defects in humans. Our study highlights the importance of the interaction between CRMP2 and KLC1 in the formation of the forebrain commissures, revealing a novel mechanism associated with CRMP2 mutations underlying human neurodevelopmental abnormalities.
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Affiliation(s)
- Simo Li
- Department of Life Science and Medical Bio-Science, Waseda University, Tokyo, Japan
| | - Youjia Guo
- Department of Life Science and Medical Bio-Science, Waseda University, Tokyo, Japan
| | - Miyuki Takahashi
- Department of Life Science and Medical Bio-Science, Waseda University, Tokyo, Japan
| | - Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Toshio Ohshima
- Department of Life Science and Medical Bio-Science, Waseda University, Tokyo, Japan
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Lumley LA, Nguyen DA, de Araujo Furtado M, Niquet J, Linz EO, Schultz CR, Stone MF, Wasterlain CG. Efficacy of Lacosamide and Rufinamide as Adjuncts to Midazolam-Ketamine Treatment Against Cholinergic-Induced Status Epilepticus in Rats. J Pharmacol Exp Ther 2024; 388:347-357. [PMID: 37977809 PMCID: PMC10801783 DOI: 10.1124/jpet.123.001789] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023] Open
Abstract
Benzodiazepine pharmacoresistance develops when treatment of status epilepticus (SE) is delayed. This response may result from gamma-aminobutyric acid A receptors (GABAAR) internalization that follows prolonged SE; this receptor trafficking results in fewer GABAAR in the synapse to restore inhibition. Increase in synaptic N-methyl-D-aspartate receptors (NMDAR) also occurs in rodent models of SE. Lacosamide, a third-generation antiseizure medication (ASM), acts on the slow inactivation of voltage-gated sodium channels. Another ASM, rufinamide, similarly acts on sodium channels by extending the duration of time spent in the inactivation stage. Combination therapy of the benzodiazepine midazolam, NMDAR antagonist ketamine, and ASMs lacosamide (or rufinamide) was investigated for efficacy against soman (GD)-induced SE and neuropathology. Adult male rats implanted with telemetry transmitters for monitoring electroencephalographic (EEG) activity were exposed to a seizure-inducing dose of GD and treated with an admix of atropine sulfate and HI-6 1 minute later and with midazolam monotherapy or combination therapy 40 minutes after EEG seizure onset. Rats were monitored continuously for seizure activity for two weeks, after which brains were processed for assessment of neurodegeneration, neuronal loss, and neuroinflammatory responses. Simultaneous administration of midazolam, ketamine, and lacosamide (or rufinamide) was more protective against GD-induced SE compared with midazolam monotherapy. In general, lacosamide triple therapy had more positive outcomes on measures of epileptogenesis, EEG power integral, and the number of brain regions protected from neuropathology compared with rats treated with rufinamide triple therapy. Overall, both drugs were well tolerated in these combination models. SIGNIFICANCE STATEMENT: We currently report on improved efficacy of antiseizure medications lacosamide and rufinamide, each administered in combination with ketamine (NMDAR antagonist) and midazolam (benzodiazepine), in combatting soman (GD)-induced seizure, epileptogenesis, and brain pathology over that provided by midazolam monotherapy, or dual therapy of midazolam and lacosamide (or rufinamide) in rats. Administration of lacosamide as adjunct to midazolam and ketamine was particularly effective against GD-induced toxicity. However, protection was incomplete, suggesting the need for further study.
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Affiliation(s)
- Lucille A Lumley
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Donna A Nguyen
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Marcio de Araujo Furtado
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Jerome Niquet
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Emily O Linz
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Caroline R Schultz
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Michael F Stone
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
| | - Claude G Wasterlain
- Neuroscience Department, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland (L.A.L., D.A.N., E.O.L., C.R.S., M.F.S.); BioSEaD, LLC, Rockville, Maryland (M.d.A.F.); and Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, and Epilepsy Research Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California (J.N., C.G.W.)
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Li Y, Tong F, Zhang Y, Cai Y, Ding J, Wang Q, Wang X. Neuropilin-2 Signaling Modulates Mossy Fiber Sprouting by Regulating Axon Collateral Formation Through CRMP2 in a Rat Model of Epilepsy. Mol Neurobiol 2022; 59:6817-6833. [PMID: 36044155 PMCID: PMC9525442 DOI: 10.1007/s12035-022-02995-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/07/2022] [Indexed: 11/30/2022]
Abstract
Programmed neural circuit formation constitutes the foundation for normal brain functions. Axon guidance cues play crucial roles in neural circuit establishment during development. Whether or how they contribute to maintaining the stability of networks in mature brains is seldom studied. Upon injury, neural rewiring could happen in adulthood, of which mossy fiber sprouting (MFS) is a canonical example. Here, we uncovered a novel role of axon guidance molecule family Sema3F/Npn-2 signaling in MFS and epileptogenesis in a rat model of epilepsy. Dentate gyrus-specific Npn-2 knockdown increased seizure activity in epileptic animals along with increased MFS. Hippocampal culture results suggested that Npn-2 signaling modulates MFS via regulating axon outgrowth and collateral formation. In addition, we discovered that Sema3F/Npn-2 signal through CRMP2 by regulating its phosphorylation in the process of MFS. Our work illustrated that Npn-2 signaling in adult epilepsy animals could potentially modulate seizure activity by controlling MFS. MFS constitutes the structural basis for abnormal electric discharge of neurons and recurrent seizures. Therapies targeting Npn-2 signaling could potentially have disease-modifying anti-epileptogenesis effects in epilepsy treatment.
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Affiliation(s)
- Yuxiang Li
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Fangchao Tong
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yiying Zhang
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yiying Cai
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jing Ding
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qiang Wang
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China.
| | - Xin Wang
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China. .,Department of The State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China.
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