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Fox PM, Malepati S, Manaster L, Rossignol E, Noebels JL. Developing a pathway to clinical trials for CACNA1A-related epilepsies: A patient organization perspective. THERAPEUTIC ADVANCES IN RARE DISEASE 2024; 5:26330040241245725. [PMID: 38681799 PMCID: PMC11047245 DOI: 10.1177/26330040241245725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 03/15/2024] [Indexed: 05/01/2024]
Abstract
CACNA1A-related disorders are rare neurodevelopmental disorders linked to variants in the CACNA1A gene. This gene encodes the α1 subunit of the P/Q-type calcium channel Cav2.1, which is globally expressed in the brain and crucial for fast synaptic neurotransmission. The broad spectrum of CACNA1A-related neurological disorders includes developmental and epileptic encephalopathies, familial hemiplegic migraine type 1, episodic ataxia type 2, spinocerebellar ataxia type 6, together with unclassified presentations with developmental delay, ataxia, intellectual disability, autism spectrum disorder, and language impairment. The severity of each disorder is also highly variable. The spectrum of CACNA1A-related seizures is broad across both loss-of-function and gain-of-function variants and includes absence seizures, focal seizures with altered consciousness, generalized tonic-clonic seizures, tonic seizures, status epilepticus, and infantile spasms. Furthermore, over half of CACNA1A-related epilepsies are refractory to current therapies. To date, almost 1700 CACNA1A variants have been reported in ClinVar, with over 400 listed as Pathogenic or Likely Pathogenic, but with limited-to-no clinical or functional data. Robust genotype-phenotype studies and impacts of variants on protein structure and function have also yet to be established. As a result, there are few definitive treatment options for CACNA1A-related epilepsies. The CACNA1A Foundation has set out to change the landscape of available and effective treatments and improve the quality of life for those living with CACNA1A-related disorders, including epilepsy. Established in March 2020, the Foundation has built a robust preclinical toolbox that includes patient-derived induced pluripotent stem cells and novel disease models, launched clinical trial readiness initiatives, and organized a global CACNA1A Research Network. This Research Network is currently composed of over 60 scientists and clinicians committed to collaborating to accelerate the path to CACNA1A-specific treatments and one day, a cure.
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Affiliation(s)
- Pangkong M. Fox
- CACNA1A Foundation, Inc., 31 Pt Road, Norwalk, CT 06854, USA
| | | | | | - Elsa Rossignol
- CACNA1A Foundation, Inc., Norwalk, CT, USA
- CHU Sainte-Justine Research Center, Departments of Neurosciences and Pediatrics, University of Montreal, Montreal, QC, Canada
| | - Jeffrey L. Noebels
- CACNA1A Foundation, Inc., Norwalk, CT, USA
- Blue Bird Circle Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA
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Shao W, Zheng H, Zhu J, Li W, Li Y, Hu W, Zhang J, Jing L, Wang K, Jiang X. Deletions of Cacna2d3 in parvalbumin-expressing neurons leads to autistic-like phenotypes in mice. Neurochem Int 2023; 169:105569. [PMID: 37419212 DOI: 10.1016/j.neuint.2023.105569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/23/2023] [Accepted: 07/04/2023] [Indexed: 07/09/2023]
Abstract
Autism spectrum disorder (ASD) is a series of highly inherited neurodevelopmental disorders. Loss-of-function (LOF) mutations in the CACNA2D3 gene are associated with ASD. However, the underlying mechanism is unknown. Dysfunction of cortical interneurons (INs) is strongly implicated in ASD. Parvalbumin-expressing (PV) INs and somatostatin-expressing (SOM) INs are the two most subtypes. Here, we characterized a mouse knockout of the Cacna2d3 gene in PV-expressing neurons (PVCre;Cacna2d3f/f mice) or in SOM-expressing neurons (SOMCre;Cacna2d3f/f mice), respectively. PVCre;Cacna2d3f/f mice showed deficits in the core ASD behavioral domains (including impaired sociability and increased repetitive behavior), as well as anxiety-like behavior and improved spatial memory. Furthermore, loss of Cacna2d3 from a subset of PV neurons results in a reduction of GAD67 and PV expression in the medial prefrontal cortex (mPFC). These may underlie the increased neuronal excitability in the mPFC, which contribute to the abnormal social behavior in PVCre;Cacna2d3f/f mice. Whereas, SOMCre;Cacna2d3f/f mice showed no obvious deficits in social, cognitive, or emotional phenotypes. Our findings provide the first evidence suggesting the causal role of Cacna2d3 insufficiency in PV neurons in autism.
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Affiliation(s)
- Wei Shao
- The School of Mental Health and Psychological Sciences, Anhui Medical University, Hefei, China
| | - Hang Zheng
- The School of Mental Health and Psychological Sciences, Anhui Medical University, Hefei, China
| | - Jingwen Zhu
- The School of Mental Health and Psychological Sciences, Anhui Medical University, Hefei, China
| | - Wenhao Li
- The School of Mental Health and Psychological Sciences, Anhui Medical University, Hefei, China
| | - Yifan Li
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Wenjie Hu
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Juanjuan Zhang
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Liang Jing
- The School of Mental Health and Psychological Sciences, Anhui Medical University, Hefei, China; Research Center for Translational Medicine, The Second Hospital of Anhui Medical University, Hefei, China; Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, China.
| | - Kai Wang
- The School of Mental Health and Psychological Sciences, Anhui Medical University, Hefei, China; Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, China; Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, China; Collaborative Innovation Center for Neuropsychiatric Disorders and Mental Health, Hefei, China; Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China.
| | - Xiao Jiang
- The School of Mental Health and Psychological Sciences, Anhui Medical University, Hefei, China; Research Center for Translational Medicine, The Second Hospital of Anhui Medical University, Hefei, China; Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, China.
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Toudji I, Toumi A, Chamberland É, Rossignol E. Interneuron odyssey: molecular mechanisms of tangential migration. Front Neural Circuits 2023; 17:1256455. [PMID: 37779671 PMCID: PMC10538647 DOI: 10.3389/fncir.2023.1256455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/21/2023] [Indexed: 10/03/2023] Open
Abstract
Cortical GABAergic interneurons are critical components of neural networks. They provide local and long-range inhibition and help coordinate network activities involved in various brain functions, including signal processing, learning, memory and adaptative responses. Disruption of cortical GABAergic interneuron migration thus induces profound deficits in neural network organization and function, and results in a variety of neurodevelopmental and neuropsychiatric disorders including epilepsy, intellectual disability, autism spectrum disorders and schizophrenia. It is thus of paramount importance to elucidate the specific mechanisms that govern the migration of interneurons to clarify some of the underlying disease mechanisms. GABAergic interneurons destined to populate the cortex arise from multipotent ventral progenitor cells located in the ganglionic eminences and pre-optic area. Post-mitotic interneurons exit their place of origin in the ventral forebrain and migrate dorsally using defined migratory streams to reach the cortical plate, which they enter through radial migration before dispersing to settle in their final laminar allocation. While migrating, cortical interneurons constantly change their morphology through the dynamic remodeling of actomyosin and microtubule cytoskeleton as they detect and integrate extracellular guidance cues generated by neuronal and non-neuronal sources distributed along their migratory routes. These processes ensure proper distribution of GABAergic interneurons across cortical areas and lamina, supporting the development of adequate network connectivity and brain function. This short review summarizes current knowledge on the cellular and molecular mechanisms controlling cortical GABAergic interneuron migration, with a focus on tangential migration, and addresses potential avenues for cell-based interneuron progenitor transplants in the treatment of neurodevelopmental disorders and epilepsy.
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Affiliation(s)
- Ikram Toudji
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Asmaa Toumi
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, Canada
| | - Émile Chamberland
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
| | - Elsa Rossignol
- Centre Hospitalier Universitaire (CHU) Sainte-Justine Research Center, Montréal, QC, Canada
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada
- Department of Pediatrics, Université de Montréal, Montréal, QC, Canada
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Inibhunu H, Moradi Chameh H, Skinner F, Rich S, Valiante TA. Hyperpolarization-Activated Cation Channels Shape the Spiking Frequency Preference of Human Cortical Layer 5 Pyramidal Neurons. eNeuro 2023; 10:ENEURO.0215-23.2023. [PMID: 37567768 PMCID: PMC10467019 DOI: 10.1523/eneuro.0215-23.2023] [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: 06/21/2023] [Revised: 07/19/2023] [Accepted: 07/20/2023] [Indexed: 08/13/2023] Open
Abstract
Discerning the contribution of specific ionic currents to complex neuronal dynamics is a difficult, but important, task. This challenge is exacerbated in the human setting, although the widely characterized uniqueness of the human brain compared with preclinical models necessitates the direct study of human neurons. Neuronal spiking frequency preference is of particular interest given its role in rhythm generation and signal transmission in cortical circuits. Here, we combine the frequency-dependent gain (FDG), a measure of spiking frequency preference, and novel in silico analyses to dissect the contributions of individual ionic currents to the suprathreshold features of human layer 5 (L5) neurons captured by the FDG. We confirm that a contemporary model of such a neuron, primarily constrained to capture subthreshold activity driven by the hyperpolarization-activated cyclic nucleotide gated (h-) current, replicates key features of the in vitro FDG both with and without h-current activity. With the model confirmed as a viable approximation of the biophysical features of interest, we applied new analysis techniques to quantify the activity of each modeled ionic current in the moments before spiking, revealing unique dynamics of the h-current. These findings motivated patch-clamp recordings in analogous rodent neurons to characterize their FDG, which confirmed that a biophysically detailed model of these neurons captures key interspecies differences in the FDG. These differences are correlated with distinct contributions of the h-current to neuronal activity. Together, this interdisciplinary and multispecies study provides new insights directly relating the dynamics of the h-current to suprathreshold spiking frequency preference in human L5 neurons.
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Affiliation(s)
- Happy Inibhunu
- Division of Clinical and Computational Neuroscience, Krembil Brain Institute, University Health Network, Toronto, Ontario M5T 1M8, Canada
| | - Homeira Moradi Chameh
- Division of Clinical and Computational Neuroscience, Krembil Brain Institute, University Health Network, Toronto, Ontario M5T 1M8, Canada
| | - Frances Skinner
- Division of Clinical and Computational Neuroscience, Krembil Brain Institute, University Health Network, Toronto, Ontario M5T 1M8, Canada
- Departments of Medicine, Neurology and Physiology, University of Toronto, Toronto, Ontario M5S 3H2, Canada
| | - Scott Rich
- Division of Clinical and Computational Neuroscience, Krembil Brain Institute, University Health Network, Toronto, Ontario M5T 1M8, Canada
| | - Taufik A Valiante
- Division of Clinical and Computational Neuroscience, Krembil Brain Institute, University Health Network, Toronto, Ontario M5T 1M8, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3E2, Canada
- Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario M5T 1P5, Canada
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Rousseau J, Tene Tadoum SB, Lavertu Jolin M, Nguyen TTM, Ajeawung NF, Flenniken AM, Nutter LMJ, Vukobradovic I, Rossignol E, Campeau PM. The ATP6V1B2 DDOD/DOORS-Associated p.Arg506* Variant Causes Hyperactivity and Seizures in Mice. Genes (Basel) 2023; 14:1538. [PMID: 37628590 PMCID: PMC10454733 DOI: 10.3390/genes14081538] [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: 06/26/2023] [Revised: 07/24/2023] [Accepted: 07/24/2023] [Indexed: 08/27/2023] Open
Abstract
The vacuolar H+-ATPase is a multisubunit enzyme which plays an essential role in the acidification and functions of lysosomes, endosomes, and synaptic vesicles. Many genes encoding subunits of V-ATPases, namely ATP6V0C, ATP6V1A, ATP6V0A1, and ATP6V1B2, have been associated with neurodevelopmental disorders and epilepsy. The autosomal dominant ATP6V1B2 p.Arg506* variant can cause both congenital deafness with onychodystrophy, autosomal dominant (DDOD) and deafness, onychodystrophy, osteodystrophy, mental retardation, and seizures syndromes (DOORS). Some but not all individuals with this truncating variant have intellectual disability and/or epilepsy, suggesting incomplete penetrance and/or variable expressivity. To further explore the impact of the p.Arg506* variant in neurodevelopment and epilepsy, we generated Atp6v1b2emR506* mutant mice and performed standardized phenotyping using the International Mouse Phenotyping Consortium (IMPC) pipeline. In addition, we assessed the EEG profile and seizure susceptibility of Atp6v1b2emR506* mice. Behavioral tests revealed that the mice present locomotor hyperactivity and show less anxiety-associated behaviors. Moreover, EEG analyses indicate that Atp6v1b2emR506* mutant mice have interictal epileptic activity and that both heterozygous (like patients) and homozygous mice have reduced seizure thresholds to pentylenetetrazol. Our results confirm that variants in ATP6V1B2 can cause seizures and that the Atp6v1b2emR506* heterozygous mouse model is a valuable tool to further explore the pathophysiology and potential treatments for vacuolar ATPases-associated epilepsy and disorders.
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Affiliation(s)
- Justine Rousseau
- CHU Sainte-Justine Research Centre, University of Montreal, Montreal, QC H3T 1C5, Canada (N.F.A.); (E.R.)
| | - Samuel Boris Tene Tadoum
- CHU Sainte-Justine Research Centre, University of Montreal, Montreal, QC H3T 1C5, Canada (N.F.A.); (E.R.)
| | - Marisol Lavertu Jolin
- CHU Sainte-Justine Research Centre, University of Montreal, Montreal, QC H3T 1C5, Canada (N.F.A.); (E.R.)
| | - Thi Tuyet Mai Nguyen
- CHU Sainte-Justine Research Centre, University of Montreal, Montreal, QC H3T 1C5, Canada (N.F.A.); (E.R.)
| | - Norbert Fonya Ajeawung
- CHU Sainte-Justine Research Centre, University of Montreal, Montreal, QC H3T 1C5, Canada (N.F.A.); (E.R.)
| | - Ann M. Flenniken
- Lunenfeld-Tanenbaum Research Institute, The Centre for Phenogenomics, Toronto, ON M5T 3H7, Canada
| | - Lauryl M. J. Nutter
- The Hospital for Sick Children, The Centre for Phenogenomics, Toronto, ON M5T 3H7, Canada
| | - Igor Vukobradovic
- Lunenfeld-Tanenbaum Research Institute, The Centre for Phenogenomics, Toronto, ON M5T 3H7, Canada
| | - Elsa Rossignol
- CHU Sainte-Justine Research Centre, University of Montreal, Montreal, QC H3T 1C5, Canada (N.F.A.); (E.R.)
| | - Philippe M. Campeau
- CHU Sainte-Justine Research Centre, University of Montreal, Montreal, QC H3T 1C5, Canada (N.F.A.); (E.R.)
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Chehrazi P, Lee KKY, Lavertu-Jolin M, Abbasnejad Z, Carreño-Muñoz MI, Chattopadhyaya B, Di Cristo G. p75 neurotrophin receptor in pre-adolescent prefrontal PV interneurons promotes cognitive flexibility in adult mice. Biol Psychiatry 2023:S0006-3223(23)01238-6. [PMID: 37120061 DOI: 10.1016/j.biopsych.2023.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 03/31/2023] [Accepted: 04/16/2023] [Indexed: 05/01/2023]
Abstract
BACKGROUND Parvalbumin (PV)-positive GABAergic cells provide robust perisomatic inhibition to neighboring pyramidal neurons and regulate brain oscillations. Alterations in PV interneuron connectivity and function in the medial prefrontal cortex (mPFC) have been consistently reported in psychiatric disorders associated with cognitive rigidity, suggesting that PV cell deficits could be a core cellular phenotype in these disorders. p75 neurotrophin receptor (p75NTR) regulates the time course of PV cell maturation in a cell-autonomous fashion. Whether p75NTR expression during postnatal development affects adult prefrontal PV cell connectivity and cognitive function is unknown. METHODS We generated transgenic mice with conditional knockout (cKO) of p75NTR in postnatal PV cells. We analysed PV cell connectivity and recruitment following a tail pinch, by immunolabeling and confocal imaging, in naïve mice or following p75NTR re-expression in pre- or post-adolescent mice using Cre-dependent viral vectors. Cognitive flexibility was evaluated using behavioral tests. RESULTS PV cell-specific p75NTR deletion increased both PV cell synapse density and the proportion of PV cells surrounded by perineuronal nets, a marker of mature PV cells, in adult mPFC but not visual cortex. Both phenotypes were rescued by viral-mediated re-introduction of p75NTR in pre-adolescent but not post-adolescent mPFC. Prefrontal cortical PV cells failed to upregulate c-Fos following a tail-pinch stimulation in adult cKO mice. Finally, cKO mice showed impaired fear memory extinction learning as well as deficits in a attention set-shifting task. CONCLUSION These findings suggest that p75NTR expression in adolescent PV cells contributes to the fine tuning of their connectivity and promotes cognitive flexibility in adulthood.
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Affiliation(s)
- Pegah Chehrazi
- Centre de Recherche, CHU Sainte-Justine (CHUSJ), Montréal, Canada; Department of Neurosciences, Université de Montréal, Montréal, Canada
| | - Karen Ka Yan Lee
- Centre de Recherche, CHU Sainte-Justine (CHUSJ), Montréal, Canada; Department of Neurosciences, Université de Montréal, Montréal, Canada
| | - Marisol Lavertu-Jolin
- Centre de Recherche, CHU Sainte-Justine (CHUSJ), Montréal, Canada; Department of Neurosciences, Université de Montréal, Montréal, Canada
| | - Zahra Abbasnejad
- Centre de Recherche, CHU Sainte-Justine (CHUSJ), Montréal, Canada; Department of Neurosciences, Université de Montréal, Montréal, Canada
| | - Maria Isabel Carreño-Muñoz
- Centre de Recherche, CHU Sainte-Justine (CHUSJ), Montréal, Canada; Department of Neurosciences, Université de Montréal, Montréal, Canada
| | | | - Graziella Di Cristo
- Centre de Recherche, CHU Sainte-Justine (CHUSJ), Montréal, Canada; Department of Neurosciences, Université de Montréal, Montréal, Canada.
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Singh M, Sapkota K, Sakimura K, Kano M, Cowell RM, Overstreet-Wadiche L, Hablitz JJ, Nakazawa K. Maturation of GABAergic Synaptic Transmission From Neocortical Parvalbumin Interneurons Involves N-methyl-D-aspartate Receptor Recruitment of Cav2.1 Channels. Neuroscience 2023; 513:38-53. [PMID: 36682446 DOI: 10.1016/j.neuroscience.2023.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/02/2023] [Accepted: 01/08/2023] [Indexed: 01/21/2023]
Abstract
N-methyl-D-aspartate receptor (NMDAR) hypofunction during brain development is likely to contribute to the manifestation of schizophrenia (SCZ) in young adulthood. The cellular targets of NMDAR hypofunction appear to be at least in part corticolimbic fast-spiking (FS) interneurons. However, functional alterations in parvalbumin (PV)-positive FS interneurons following NMDAR hypofunction are poorly understood. Paired patch-clamp recordings from murine cortical PV interneurons and pyramidal neurons revealed that genetic deletion of NMDAR subunit Grin1 in prospective PV interneurons before the second postnatal week impaired evoked- and synchronized-GABA release. Whereas intrinsic excitability and spiking characteristics were also disturbed by Grin1 deletion, neither restoring their excitability by K+ channel blockade nor increasing extracellular Ca2+ rescued the GABA release. GABA release was also insensitive to the Cav2.1 channel antagonist ω-agatoxin IVA. Heterozygous deletion of Cacna1a gene (encoding Cav2.1) in PV interneurons produced a similar GABA release phenotype as the Grin1 mutants. Treatment with the Cav2.1/2.2 channel agonist GV-58 augmented somatic Ca2+ currents and GABA release in Cacna1a-haploinsufficient PV interneurons, but failed to enhance GABA release in the Grin1-deleted PV interneurons. Taken together, our results suggest that Grin1 deletion in prospective PV interneurons impairs proper maturation of membrane excitability and Cav2.1-recruited evoked GABA release. This may increase synaptic excitatory/inhibitory ratio in principal neurons, contributing to the emergence of SCZ-like phenotypes.
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Affiliation(s)
- Mahendra Singh
- Department of Neuroscience, Scientific Platforms, Southern Research, Birmingham, AL 35205, USA; Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Kiran Sapkota
- Department of Neuroscience, Scientific Platforms, Southern Research, Birmingham, AL 35205, USA
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan; International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Tokyo 113-0033, Japan
| | - Rita M Cowell
- Department of Neuroscience, Scientific Platforms, Southern Research, Birmingham, AL 35205, USA; Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Department of Neurology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | | | - John J Hablitz
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Kazu Nakazawa
- Department of Neuroscience, Scientific Platforms, Southern Research, Birmingham, AL 35205, USA; Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Abstract
The fundamental commonality across pharmacotherapies for the epilepsies
is the modulation of neuronal excitability. This poses a clear
challenge—patterned neuronal excitation is essential to normal
function, thus disrupting this activity leads to side effects.
Moreover, the efficacy of current pharmacotherapy remains incomplete
despite decades of drug development. Approaches that allow for the
selective targeting of critical populations of cells and particular
pathways in the brain have the potential to both avoid side effects
and improve efficacy. Chemogenetic methods, which combine the
selective expression of designer receptors with designer drugs, have
rapidly grown in use in the neurosciences, including in epilepsy. This
review will briefly highlight the history of chemogenetics, their
applications to date in epilepsy, and the potential (and potential
hurdles to overcome) for future translation.
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Affiliation(s)
- Patrick A. Forcelli
- Department of Pharmacology & Physiology, Georgetown University, Washington, DC, USA
- Department of Neuroscience, Georgetown University, Washington, DC, USA
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, USA
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Nakao A, Hayashida K, Ogura H, Mori Y, Imoto K. Hippocampus-related cognitive disorders develop in the absence of epilepsy and ataxia in the heterozygous Cacna1a mutant mice tottering. Channels (Austin) 2022; 16:113-126. [PMID: 35548926 PMCID: PMC9103357 DOI: 10.1080/19336950.2022.2072449] [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] [Indexed: 11/17/2022] Open
Abstract
CACNA1A-associated epilepsy and ataxia frequently accompany cognitive impairments as devastating co-morbidities. However, it is unclear whether the cognitive deficits are consequences secondary to the neurological symptoms elicited by CACNA1A mutations. To address this issue, Cacna1a mutant mice tottering (tg), and in particular tg/+ heterozygotes, serve as a suitable model system, given that tg/+ heterozygotes fail to display spontaneous absence epilepsy and ataxia typically observed in tg/tg homozygotes. Here, we examined hippocampus-dependent behaviors and hippocampal learning-related synaptic plasticity in tg mice. In behavioral analyses of tg/+ and tg/tg, acquisition and retention of spatial reference memory were characteristically impaired in the Morris water maze task, while working memory was intact in the eight-arm radial maze and T-maze tasks. tg/+ heterozygotes showed normal motor function in contrast to tg/tg homozygotes. In electrophysiological analyses, Schaffer collateral–CA1 synapses showed a deficit in the maintenance of long-term potentiation in tg/+ and tg/tg mice and an increased paired-pulse facilitation induced by paired pulses with 100 ms in tg/tg mice. Our results indicate that the tg mutation causes a dominant disorder of the hippocampus-related memory and synaptic plasticity, raising the possibility that in CACNA1A-associated human diseases, functionally aberrant CaV2.1 Ca2+ channels actively induce the observed cognitive deficits independently of the neurological symptoms.
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Affiliation(s)
- Akito Nakao
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Katsumi Hayashida
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Hiroo Ogura
- Product Creation Headquarters, Eisai Corporate, Limited, Tokyo, Japan
| | - Yasuo Mori
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Keiji Imoto
- Division of Neural Signaling, Department of Information Physiology, National Institute for Physiological Sciences, Okazaki, Japan
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