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Liebergall SR, Goldberg EM. Ndnf Interneuron Excitability Is Spared in a Mouse Model of Dravet Syndrome. J Neurosci 2024; 44:e1977232024. [PMID: 38443186 PMCID: PMC11044195 DOI: 10.1523/jneurosci.1977-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 01/10/2024] [Accepted: 01/30/2024] [Indexed: 03/07/2024] Open
Abstract
Dravet syndrome (DS) is a neurodevelopmental disorder characterized by epilepsy, developmental delay/intellectual disability, and features of autism spectrum disorder, caused by heterozygous loss-of-function variants in SCN1A encoding the voltage-gated sodium channel α subunit Nav1.1. The dominant model of DS pathogenesis is the "interneuron hypothesis," whereby GABAergic interneurons (INs) express and preferentially rely on Nav1.1-containing sodium channels for action potential (AP) generation. This has been shown for three of the major subclasses of cerebral cortex GABAergic INs: those expressing parvalbumin (PV), somatostatin, and vasoactive intestinal peptide. Here, we define the function of a fourth major subclass of INs expressing neuron-derived neurotrophic factor (Ndnf) in male and female DS (Scn1a+/-) mice. Patch-clamp electrophysiological recordings of Ndnf-INs in brain slices from Scn1a+/â mice and WT controls reveal normal intrinsic membrane properties, properties of AP generation and repetitive firing, and synaptic transmission across development. Immunohistochemistry shows that Nav1.1 is strongly expressed at the axon initial segment (AIS) of PV-expressing INs but is absent at the Ndnf-IN AIS. In vivo two-photon calcium imaging demonstrates that Ndnf-INs in Scn1a+/â mice are recruited similarly to WT controls during arousal. These results suggest that Ndnf-INs are the only major IN subclass that does not prominently rely on Nav1.1 for AP generation and thus retain their excitability in DS. The discovery of a major IN subclass with preserved function in the Scn1a+/â mouse model adds further complexity to the "interneuron hypothesis" and highlights the importance of considering cell-type heterogeneity when investigating mechanisms underlying neurodevelopmental disorders.
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Affiliation(s)
- Sophie R Liebergall
- Department of Neuroscience, The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
- Neuroscience Graduate Group, The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
- Medical Scientist Training Program, The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Ethan M Goldberg
- Department of Neuroscience, The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
- Neuroscience Graduate Group, The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
- Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
- The Epilepsy Neurogenetics Initiative, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104
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Santos VR, Tilelli CQ, Fernandes A, de Castro OW, Del-Vecchio F, Garcia-Cairasco N. Different types of Status Epilepticus may lead to similar hippocampal epileptogenesis processes. IBRO Neurosci Rep 2023; 15:68-76. [PMID: 37457787 PMCID: PMC10338355 DOI: 10.1016/j.ibneur.2023.06.001] [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: 02/15/2023] [Revised: 06/05/2023] [Accepted: 06/05/2023] [Indexed: 07/18/2023] Open
Abstract
About 1-2% of people worldwide suffer from epilepsy, which is characterized by unpredictable and intermittent seizure occurrence. Despite the fact that the exact origin of temporal lobe epilepsy is frequently unknown, it is frequently linked to an early triggering insult like brain damage, tumors, or Status Epilepticus (SE). We used an experimental approach consisting of electrical stimulation of the amygdaloid complex to induce two behaviorally and structurally distinct SE states: Type I (fully convulsive), with more severe seizure behaviors and more extensive brain damage, and Type II (partial convulsive), with less severe seizure behaviors and brain damage. Our goal was to better understand how the various types of SE impact the hippocampus leading to the development of epilepsy. Despite clear variations between the two behaviors in terms of neurodegeneration, study of neurogenesis revealed a comparable rise in the number of Ki-67 + cells and an increase in Doublecortin (DCX) in both kinds of SE.
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Affiliation(s)
- Victor R. Santos
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, MG, Brazil
| | - Cristiane Q. Tilelli
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
- Campus Centro-Oeste Dona Lindu, Federal University of São João Del Rey, Divinópolis, MG, Brazil
| | - Artur Fernandes
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Olagide Wagner de Castro
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
- Department of Pharmacology and Physiology, Universidade Federal de Alagoas, Maceió, AL, Brazil
| | - Flávio Del-Vecchio
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Norberto Garcia-Cairasco
- Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
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Damasceno S, Gómez-Nieto R, Garcia-Cairasco N, Herrero-Turrión MJ, Marín F, Lopéz DE. Top Common Differentially Expressed Genes in the Epileptogenic Nucleus of Two Strains of Rodents Susceptible to Audiogenic Seizures: WAR and GASH/Sal. Front Neurol 2020; 11:33. [PMID: 32117006 PMCID: PMC7031349 DOI: 10.3389/fneur.2020.00033] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 01/10/2020] [Indexed: 11/16/2022] Open
Abstract
The Wistar Audiogenic Rat (WAR) and the Genetic Audiogenic Seizure Hamster from Salamanca (GASH/Sal) strains are audiogenic epilepsy models, in which seizures are triggered by acoustic stimulation. These strains were developed by selective reproduction and have a genetic background with minimal or no variation. In the current study, we evaluated the transcriptome of the inferior colliculus, the epileptogenic nucleus, of both audiogenic models, in order to get insights into common molecular aspects associated to their epileptic phenotype. Based on GASH/Sal RNA-Seq and WAR microarray data, we performed a comparative analysis that includes selection and functional annotation of differentially regulated genes in each model, transcriptional evaluation by quantitative reverse transcription PCR of common genes identified in both transcriptomes and immunohistochemistry. The microarray data revealed 71 genes with differential expression in WAR, and the RNA-Seq data revealed 64 genes in GASH/Sal, showing common genes in both models. Analysis of transcripts showed that Egr3 was overexpressed in WAR and GASH/Sal after audiogenic seizures. The Npy, Rgs2, Ttr, and Abcb1a genes presented the same transcriptional profile in the WAR, being overexpressed in the naïve and stimulated WAR in relation to their controls. Npy appeared overexpressed only in the naïve GASH/Sal compared to its control, while Rgs2 and Ttr genes appeared overexpressed in naïve GASH/Sal and overexpressed after audiogenic seizure. No statistical difference was observed in the expression of Abcb1a in the GASH/Sal model. Compared to control animals, the immunohistochemical analysis of the inferior colliculus showed an increased immunoreactivity for NPY, RGS2, and TTR in both audiogenic models. Our data suggest that WAR and GASH/Sal strains have a difference in the timing of gene expression after seizure, in which GASH/Sal seems to respond more quickly. The transcriptional profile of the Npy, Rgs2, and Ttr genes under free-seizure conditions in both audiogenic models indicates an intrinsic expression already established in the strains. Our findings suggest that these genes may be causing small changes in different biological processes involved in seizure occurrence and response, and indirectly contributing to the susceptibility of the WAR and GASH/Sal models to audiogenic seizures.
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Affiliation(s)
- Samara Damasceno
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain
| | - Ricardo Gómez-Nieto
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain.,Salamanca Institute for Biomedical Research, Salamanca, Spain
| | | | - Manuel Javier Herrero-Turrión
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain.,INCYL Neurological Tissue Bank (BTN-INCYL), Salamanca, Spain
| | - Faustino Marín
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia, Murcia, Spain
| | - Dolores E Lopéz
- Institute of Neurosciences of Castilla y León, University of Salamanca, Salamanca, Spain.,Salamanca Institute for Biomedical Research, Salamanca, Spain
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Buffel I, Meurs A, Portelli J, Raedt R, De Herdt V, Sioncke L, Wadman W, Bihel F, Schmitt M, Vonck K, Bourguignon JJ, Simonin F, Smolders I, Boon P. Neuropeptide FF and prolactin-releasing peptide decrease cortical excitability through activation of NPFF receptors. Epilepsia 2015; 56:489-98. [PMID: 25684325 DOI: 10.1111/epi.12928] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Drugs with a novel mechanism of action are needed to reduce the number of people with epilepsy that are refractory to treatment. Increasing attention is paid to neuropeptide systems and several anticonvulsant neuropeptides have already been described, such as galanin, ghrelin, and neuropeptide Y (NPY). Many others, however, have not been investigated for their ability to affect epileptic seizures. In this study, the potential anticonvulsant activities of three members of the RF-amide neuropeptide family, neuropeptide FF (NPFF), prolactin-releasing peptide (PrRP), and kisspeptin (Kp) and other receptor ligands (NPFF1/2 R, GPR10, and GRP54, respectively) were tested in the motor cortex stimulation model. METHODS A train of pulses with increasing intensity (0-10 mA over 150 s, 50 Hz, pulse width 2 msec) was delivered to the motor cortex of rats. The threshold intensity for eliciting a motor response (i.e., motor threshold) was determined through behavioral observation and used as a measure for cortical excitability. The threshold was determined before, during, and after the intracerebroventricular (i.c.v.) administration of various NPFF1/2 R, GPR10, and GPR54 receptor ligands. RESULTS NPFF and PrRP significantly increased the motor threshold by a maximum of 143 ± 27 and 83 ± 13 μA, respectively, for the doses of 1 nmol/h (p < 0.05). The increase of motor threshold by NPFF and PrRP was prevented by pretreatment and co-treatment with the NPFF1/2 R antagonist RF9. Pretreatment with a selective NPFF1 R antagonist also prevented the threshold increase induced by NPFF. Kp did not increase motor threshold. SIGNIFICANCE Intracerebroventricular infusion of NPFF or PrRP decreases cortical excitability in rats through activation of NPFFRs. Furthermore, the NPFF1 R is required for the NPFF-induced decrease in cortical excitability.
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Affiliation(s)
- Ine Buffel
- Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Neurology, Ghent University Hospital, Ghent University, Ghent, Belgium
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Mercer AJ, Hentges ST, Meshul CK, Low MJ. Unraveling the central proopiomelanocortin neural circuits. Front Neurosci 2013; 7:19. [PMID: 23440036 PMCID: PMC3579188 DOI: 10.3389/fnins.2013.00019] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 02/04/2013] [Indexed: 11/16/2022] Open
Abstract
Central proopiomelanocortin (POMC) neurons form a potent anorexigenic network, but our understanding of the integration of this hypothalamic circuit throughout the central nervous system (CNS) remains incomplete. POMC neurons extend projections along the rostrocaudal axis of the brain, and can signal with both POMC-derived peptides and fast amino acid neurotransmitters. Although recent experimental advances in circuit-level manipulation have been applied to POMC neurons, many pivotal questions still remain: how and where do POMC neurons integrate metabolic information? Under what conditions do POMC neurons release bioactive molecules throughout the CNS? Are GABA and glutamate or neuropeptides released from POMC neurons more crucial for modulating feeding and metabolism? Resolving the exact stoichiometry of signals evoked from POMC neurons under different metabolic conditions therefore remains an ongoing endeavor. In this review, we analyze the anatomical atlas of this network juxtaposed to the physiological signaling of POMC neurons both in vitro and in vivo. We also consider novel genetic tools to further characterize the function of the POMC circuit in vivo. Our goal is to synthesize a global view of the POMC network, and to highlight gaps that require further research to expand our knowledge on how these neurons modulate energy balance.
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Affiliation(s)
- Aaron J Mercer
- Department of Molecular and Integrative Physiology, University of Michigan Ann Arbor, MI, USA
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Sohn JW, Williams KW. Functional heterogeneity of arcuate nucleus pro-opiomelanocortin neurons: implications for diverging melanocortin pathways. Mol Neurobiol 2012; 45:225-33. [PMID: 22328135 DOI: 10.1007/s12035-012-8240-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 01/26/2012] [Indexed: 01/04/2023]
Abstract
Arcuate nucleus (ARC) pro-opiomelanocortin (POMC) neurons are essential regulators of food intake, energy expenditure, and glucose homeostasis. POMC neurons integrate several key metabolic signals that include neurotransmitters and hormones. The change in activity of POMC neurons is relayed to melanocortin receptors in distinct regions of the central nervous system. This review will summarize the role of leptin and serotonin receptors in regulating the activity of POMC neurons and provide a model in which different melanocortin pathways regulate energy and glucose homeostasis.
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Affiliation(s)
- Jong-Woo Sohn
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390-9077, USA
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Ghanizadeh A. Ghrelin as a promising therapeutic target for co-occurring autism and epilepsy. Epilepsy Behav 2011; 20:420-1. [PMID: 21220213 DOI: 10.1016/j.yebeh.2010.12.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 12/07/2010] [Indexed: 01/09/2023]
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Thom M, Martinian L, Catarino C, Yogarajah M, Koepp MJ, Caboclo L, Sisodiya SM. Bilateral reorganization of the dentate gyrus in hippocampal sclerosis: a postmortem study. Neurology 2009; 73:1033-40. [PMID: 19710404 DOI: 10.1212/wnl.0b013e3181b99a07] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Hippocampal sclerosis (HS) is the most common surgical pathology associated with mesial temporal lobe epilepsy (MTLE). HS is typically characterized by mossy fiber sprouting (MFS) and reorganization of neuropeptide Y (NPY) fiber networks in the dentate gyrus. One potential cause of postoperative seizure recurrence following temporal lobe surgery may be the presence of seizure-associated bilateral hippocampal damage. We aimed to investigate patterns of hippocampal abnormalities in a postmortem series as identified by NPY and dynorphin immunohistochemistry. METHODS Analysis of dentate gyrus fiber reorganization, using dynorphin (to demonstrate MFS) and NPY immunohistochemistry, was carried out in a postmortem epilepsy series of 25 cases (age range 21-96 years). In 9 patients, previously refractory seizures had become well controlled for up to 34 years prior to death. RESULTS Bilateral MFS or abnormal NPY patterns were seen in 15 patients including those with bilateral symmetric, asymmetric, and unilateral HS by conventional histologic criteria. MFS and NPY reorganization was present in all classical HS cases, more variably in atypical HS, present in both MTLE and non-MTLE syndromes and with seizure histories of up to 92 years, despite seizure remission in some patients. CONCLUSION Synaptic reorganization in the dentate gyrus may be a bilateral, persistent process in epilepsy. It is unlikely to be sufficient to generate seizures and more likely to represent a seizure-induced phenomenon.
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Affiliation(s)
- M Thom
- Department of Clinical and Experimental Epilepsy, Division of Neuropathology, Institute of Neurology, Queen Square, London, UK.
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Do Rego JL, Seong JY, Burel D, Leprince J, Luu-The V, Tsutsui K, Tonon MC, Pelletier G, Vaudry H. Neurosteroid biosynthesis: enzymatic pathways and neuroendocrine regulation by neurotransmitters and neuropeptides. Front Neuroendocrinol 2009; 30:259-301. [PMID: 19505496 DOI: 10.1016/j.yfrne.2009.05.006] [Citation(s) in RCA: 282] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 05/12/2009] [Accepted: 05/21/2009] [Indexed: 01/09/2023]
Abstract
Neuroactive steroids synthesized in neuronal tissue, referred to as neurosteroids, are implicated in proliferation, differentiation, activity and survival of nerve cells. Neurosteroids are also involved in the control of a number of behavioral, neuroendocrine and metabolic processes such as regulation of food intake, locomotor activity, sexual activity, aggressiveness, anxiety, depression, body temperature and blood pressure. In this article, we summarize the current knowledge regarding the existence, neuroanatomical distribution and biological activity of the enzymes responsible for the biosynthesis of neurosteroids in the brain of vertebrates, and we review the neuronal mechanisms that control the activity of these enzymes. The observation that the activity of key steroidogenic enzymes is finely tuned by various neurotransmitters and neuropeptides strongly suggests that some of the central effects of these neuromodulators may be mediated via the regulation of neurosteroid production.
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Affiliation(s)
- Jean Luc Do Rego
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 413, 76821 Mont-Saint-Aignan, France
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Minor RK, Chang JW, de Cabo R. Hungry for life: How the arcuate nucleus and neuropeptide Y may play a critical role in mediating the benefits of calorie restriction. Mol Cell Endocrinol 2009; 299:79-88. [PMID: 19041366 PMCID: PMC2668104 DOI: 10.1016/j.mce.2008.10.044] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Accepted: 10/14/2008] [Indexed: 11/27/2022]
Abstract
Laboratory studies consistently demonstrate extended lifespan in animals on calorie restriction (CR), where total caloric intake is reduced by 10-40% but adequate nutrition is otherwise maintained. CR has been further shown to delay the onset and severity of chronic diseases associated with aging such as cancer, and to extend the functional health span of important faculties like cognition. Less understood are the underlying mechanisms through which CR might act to induce such alterations. One theory postulates that CR's beneficial effects are intimately tied to the neuroendocrine response to low energy availability, of which the arcuate nucleus in the hypothalamus plays a pivotal role. Neuropeptide Y (NPY), a neurotransmitter in the front line of the arcuate response to low energy availability, is the primary hunger signal affected by CR and therefore may be a critical mechanism for lifespan extension.
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Affiliation(s)
- Robin K. Minor
- Laboratory of Experimental Gerontology, Intramural Research Program, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
| | - Joy W. Chang
- Laboratory of Experimental Gerontology, Intramural Research Program, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
| | - Rafael de Cabo
- Laboratory of Experimental Gerontology, Intramural Research Program, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
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