1
|
Richardson RJ, Petrou S, Bryson A. Established and emerging GABA A receptor pharmacotherapy for epilepsy. Front Pharmacol 2024; 15:1341472. [PMID: 38449810 PMCID: PMC10915249 DOI: 10.3389/fphar.2024.1341472] [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: 11/20/2023] [Accepted: 02/07/2024] [Indexed: 03/08/2024] Open
Abstract
Drugs that modulate the GABAA receptor are widely used in clinical practice for both the long-term management of epilepsy and emergency seizure control. In addition to older medications that have well-defined roles for the treatment of epilepsy, recent discoveries into the structure and function of the GABAA receptor have led to the development of newer compounds designed to maximise therapeutic benefit whilst minimising adverse effects, and whose position within the epilepsy pharmacologic armamentarium is still emerging. Drugs that modulate the GABAA receptor will remain a cornerstone of epilepsy management for the foreseeable future and, in this article, we provide an overview of the mechanisms and clinical efficacy of both established and emerging pharmacotherapies.
Collapse
Affiliation(s)
- Robert J. Richardson
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
- Department of Neurology, Austin Health, Heidelberg, VIC, Australia
| | - Steven Petrou
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
- Praxis Precision Medicines, Boston, MA, United States
| | - Alexander Bryson
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
- Department of Neurology, Austin Health, Heidelberg, VIC, Australia
- Department of Neurology, Eastern Health, Melbourne, VIC, Australia
| |
Collapse
|
2
|
Teng L, Qin Q, Zhou Z, Zhou F, Cao C, Yang J, Ding J. Glutamate secretion by embryonic stem cells as an autocrine signal to promote proliferation. Sci Rep 2023; 13:19069. [PMID: 37925518 PMCID: PMC10625544 DOI: 10.1038/s41598-023-46477-2] [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: 07/05/2023] [Accepted: 11/01/2023] [Indexed: 11/06/2023] Open
Abstract
Glutamate, the major excitatory neurotransmitter in the central nervous system, has also been found to play a role in embryonic stem (ES) cells. However, the exact mechanism and function of glutamatergic signaling in ES cells remain poorly understood. In this study, we identified a glutamatergic transmission circuit in ES cells that operates through an autocrine mechanism and regulates cell proliferation. We performed biological analyses to identify the key components involved in glutamate biosynthesis, packaging for secretion, reaction, and reuptake in ES cells, including glutaminase, vesicular glutamate transporter, glutamate N-methyl-D-aspartate (NMDA) receptor, and cell membrane excitatory amino-acid transporter (EAAT). We directly quantified the released glutamate signal using microdialysis-high performance liquid chromatography-tandem mass spectrometry (MD-HPLC-MS-MS). Pharmacological inhibition of endogenous glutamate release and the resulting tonic activation of NMDA receptors significantly affected ES cell proliferation, suggesting that ES cells establish a glutamatergic autocrine niche via releasing and responding to the transmitter for their own regulation.
Collapse
Affiliation(s)
- Lin Teng
- Department of Cardiology, Yichang Central People's Hospital/The First College of Clinical Medical Sciences, China Three Gorges University, No. 183 Yiling Road, Yichang, 443003, Hubei, China
- Institute of Cardiovascular Disease, China Three Gorges University, Yichang, 443003, Hubei, China
- College of Basic Medical Sciences, Hubei Key Laboratory of Tumor Microencironment and Immunotherapy, China Three Gorges University, Yichang, 443000, Hubei, China
| | - Qin Qin
- Department of Cardiology, Yichang Central People's Hospital/The First College of Clinical Medical Sciences, China Three Gorges University, No. 183 Yiling Road, Yichang, 443003, Hubei, China
- Institute of Cardiovascular Disease, China Three Gorges University, Yichang, 443003, Hubei, China
| | - Ziyi Zhou
- Department of Cardiology, Yichang Central People's Hospital/The First College of Clinical Medical Sciences, China Three Gorges University, No. 183 Yiling Road, Yichang, 443003, Hubei, China
- Institute of Cardiovascular Disease, China Three Gorges University, Yichang, 443003, Hubei, China
| | - Fei Zhou
- Department of Cardiology, Yichang Central People's Hospital/The First College of Clinical Medical Sciences, China Three Gorges University, No. 183 Yiling Road, Yichang, 443003, Hubei, China
- Institute of Cardiovascular Disease, China Three Gorges University, Yichang, 443003, Hubei, China
| | - Chunyu Cao
- College of Basic Medical Sciences, Hubei Key Laboratory of Tumor Microencironment and Immunotherapy, China Three Gorges University, Yichang, 443000, Hubei, China
| | - Jian Yang
- Department of Cardiology, Yichang Central People's Hospital/The First College of Clinical Medical Sciences, China Three Gorges University, No. 183 Yiling Road, Yichang, 443003, Hubei, China
- Institute of Cardiovascular Disease, China Three Gorges University, Yichang, 443003, Hubei, China
| | - Jiawang Ding
- Department of Cardiology, Yichang Central People's Hospital/The First College of Clinical Medical Sciences, China Three Gorges University, No. 183 Yiling Road, Yichang, 443003, Hubei, China.
- Institute of Cardiovascular Disease, China Three Gorges University, Yichang, 443003, Hubei, China.
| |
Collapse
|
3
|
Che YH, Choi IY, Song CE, Park C, Lim SK, Kim JH, Sung SH, Park JH, Lee S, Kim YJ. Peripheral Neuron-Organoid Interaction Induces Colonic Epithelial Differentiation via Non-Synaptic Substance P Secretion. Int J Stem Cells 2023; 16:269-280. [PMID: 37385635 PMCID: PMC10465334 DOI: 10.15283/ijsc23026] [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: 03/08/2023] [Revised: 04/04/2023] [Accepted: 04/06/2023] [Indexed: 07/01/2023] Open
Abstract
Background and Objectives The colonic epithelial layer is a complex structure consisting of multiple cell types that regulate various aspects of colonic physiology, yet the mechanisms underlying epithelial cell differentiation during development remain unclear. Organoids have emerged as a promising model for investigating organogenesis, but achieving organ-like cell configurations within colonic organoids is challenging. Here, we investigated the biological significance of peripheral neurons in the formation of colonic organoids. Methods and Results Colonic organoids were co-cultured with human embryonic stem cell (hESC)-derived peripheral neurons, resulting in the morphological maturation of columnar epithelial cells, as well as the presence of enterochromaffin cells. Substance P released from immature peripheral neurons played a critical role in the development of colonic epithelial cells. These findings highlight the vital role of inter-organ interactions in organoid development and provide insights into colonic epithelial cell differentiation mechanisms. Conclusions Our results suggest that the peripheral nervous system may have a significant role in the development of colonic epithelial cells, which could have important implications for future studies of organogenesis and disease modeling.
Collapse
Affiliation(s)
- Young Hyun Che
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
| | - In Young Choi
- The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Medicine, Graduate School, Kyung Hee University, Seoul, Korea
| | - Chan Eui Song
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
| | - Chulsoon Park
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
| | - Seung Kwon Lim
- Department of Medicine, Graduate School, Kyung Hee University, Seoul, Korea
| | - Jeong Hee Kim
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
| | - Su Haeng Sung
- Department of Pathology, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Jae Hoon Park
- Department of Pathology, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Sun Lee
- Department of Pathology, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Yong Jun Kim
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
- Department of Medicine, Graduate School, Kyung Hee University, Seoul, Korea
- Department of Pathology, College of Medicine, Kyung Hee University, Seoul, Korea
- KHU-KIST Department of Converging Science and Technology, Graduate School, Kyung Hee University, Seoul, Korea
| |
Collapse
|
4
|
Furukawa T, Fukuda A. Maternal taurine as a modulator of Cl - homeostasis as well as of glycine/GABA A receptors for neocortical development. Front Cell Neurosci 2023; 17:1221441. [PMID: 37601283 PMCID: PMC10435090 DOI: 10.3389/fncel.2023.1221441] [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: 05/12/2023] [Accepted: 07/20/2023] [Indexed: 08/22/2023] Open
Abstract
During brain and spinal cord development, GABA and glycine, the inhibitory neurotransmitters, cause depolarization instead of hyperpolarization in adults. Since glycine and GABAA receptors (GABAARs) are chloride (Cl-) ion channel receptor, the conversion of GABA/glycine actions during development is influenced by changes in the transmembrane Cl- gradient, which is regulated by Cl- transporters, NKCC1 (absorption) and KCC2 (expulsion). In immature neurons, inhibitory neurotransmitters are released in a non-vesicular/non-synaptic manner, transitioning to vesicular/synaptic release as the neuron matures. In other word, in immature neurons, neurotransmitters generally act tonically. Thus, the glycine/GABA system is a developmentally multimodal system that is required for neurogenesis, differentiation, migration, and synaptogenesis. The endogenous agonists for these receptors are not fully understood, we address taurine. In this review, we will discuss about the properties and function of taurine during development of neocortex. Taurine cannot be synthesized by fetuses or neonates, and is transferred from maternal blood through the placenta or maternal milk ingestion. In developing neocortex, taurine level is higher than GABA level, and taurine tonically activates GABAARs to control radial migration as a stop signal. In the marginal zone (MZ) of the developing neocortex, endogenous taurine modulates the spread of excitatory synaptic transmission, activating glycine receptors (GlyRs) as an endogenous agonist. Thus, taurine affects information processing and crucial developmental processes such as axonal growth, cell migration, and lamination in the developing cerebral cortex. Additionally, we also refer to the possible mechanism of taurine-regulating Cl- homeostasis. External taurine is uptake by taurine transporter (TauT) and regulates NKCC1 and KCC2 mediated by intracellular signaling pathway, with-no-lysine kinase 1 (WNK1) and its subsequent kinases STE20/SPS1-related proline-alanine-rich protein kinase (SPAK) and oxidative stress response kinase-1 (OSR1). Through the regulation of NKCC1 and KCC2, mediated by the WNK-SPAK/OSR1 signaling pathway, taurine plays a role in maintaining Cl- homeostasis during normal brain development.
Collapse
Affiliation(s)
- Tomonori Furukawa
- Department of Neurophysiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| |
Collapse
|
5
|
Valerio E, Stocchero M, Pirillo P, D'Errico I, Bonadies L, Galderisi A, Giordano G, Baraldi E. Neurosteroid pathway derangement in asphyctic infants treated with hypothermia: an untargeted metabolomic approach. EBioMedicine 2023; 92:104636. [PMID: 37257315 PMCID: PMC10244906 DOI: 10.1016/j.ebiom.2023.104636] [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: 02/23/2023] [Revised: 04/29/2023] [Accepted: 05/15/2023] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND The pathobiological mechanisms associated with perinatal asphyxia and hypoxic-ischemic encephalopathy are complex and poorly understood. The metabolic effects of therapeutic hypothermia have been partially explored. METHODS We conducted a single-center longitudinal study to investigate the metabolic effects of perinatal asphyxia and hypoxic-ischemic encephalopathy on the urinary metabolome of a group of 12 asphyctic infants over time compared to 22 matched healthy newborns, using untargeted metabolomics based on mass spectrometry. FINDINGS Over-representation pathway analysis identified the steroidogenesis pathway as being significantly disrupted, with reduced steroid levels in the first three days of life despite treatment with hypothermia. Comparison with matched healthy newborns showed that the urinary steroid content was lower in asphyctic infants before hypothermia. The lysine degradation and carnitine synthesis pathways were also significantly affected. INTERPRETATION Steroidogenesis is significantly disrupted in asphyctic infants compared to healthy newborns. Given how neurosteroids are involved in neuromodulation and neuroprotection, translational research is warranted on the potential role of neurosteroid-based intervention in asphyctic infants. FUNDING None.
Collapse
Affiliation(s)
- Enrico Valerio
- Neonatal Intensive Care Unit, Department of Woman's and Child's Health, Azienda Ospedale-Università di Padova, Italy; Institute of Pediatric Research "Città Della Speranza", Padova, Italy
| | - Matteo Stocchero
- Neonatal Intensive Care Unit, Department of Woman's and Child's Health, Azienda Ospedale-Università di Padova, Italy; Institute of Pediatric Research "Città Della Speranza", Padova, Italy
| | - Paola Pirillo
- Neonatal Intensive Care Unit, Department of Woman's and Child's Health, Azienda Ospedale-Università di Padova, Italy; Institute of Pediatric Research "Città Della Speranza", Padova, Italy
| | - Ignazio D'Errico
- Department of Neuroradiology, Azienda Ospedale-Università di Padova, Italy
| | - Luca Bonadies
- Neonatal Intensive Care Unit, Department of Woman's and Child's Health, Azienda Ospedale-Università di Padova, Italy; Institute of Pediatric Research "Città Della Speranza", Padova, Italy
| | - Alfonso Galderisi
- Neonatal Intensive Care Unit, Department of Woman's and Child's Health, Azienda Ospedale-Università di Padova, Italy; Department of Pediatrics, Yale School of Medicine, Yale University, New Haven, CT 06511, USA
| | - Giuseppe Giordano
- Neonatal Intensive Care Unit, Department of Woman's and Child's Health, Azienda Ospedale-Università di Padova, Italy; Institute of Pediatric Research "Città Della Speranza", Padova, Italy
| | - Eugenio Baraldi
- Neonatal Intensive Care Unit, Department of Woman's and Child's Health, Azienda Ospedale-Università di Padova, Italy; Institute of Pediatric Research "Città Della Speranza", Padova, Italy.
| |
Collapse
|
6
|
Adak P, Banerjee N, Sinha S, Bandyopadhyay AK. Gamma-Aminobutyric Acid Type A Receptor Variants are Associated with Autism Spectrum Disorders. J Mol Neurosci 2023; 73:237-249. [PMID: 36943547 DOI: 10.1007/s12031-023-02113-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 03/01/2023] [Indexed: 03/23/2023]
Abstract
Despite several efforts to identify the causes of autism spectrum disorders (ASD), its etiology remains still unclear. Among other aspects, genes that encode neurotransmitter receptors are strong candidates for autism. Here, we wanted to study some genetic variants of gamma-aminobutyric acid (GABA) receptor subunit genes GABRB3, GABRG3, and GABRA5, located on chromosome 15q11-q13 that might contribute to the etiology of ASD in the affected children of West Bengal. rs7180158, rs2081648 (GABRB3); rs12910555 (GABRG3); rs35399885, rs35832850 (GABRA5) were analyzed in 316 children with ASD and 227 healthy controls. Phenotypic associations were evaluated by Childhood Autism Rating Scale (CARS). Gene expression levels were measured by quantitative real-time PCR. ASD probands showed a higher frequency of "A" allele for rs7180158, "G" allele for rs12901555, and "T" allele for rs35399885. The GA + AA genotypes (rs7180158) and CT + TT genotypes (rs35399885) were found to confer significant risk towards ASD. rs2081648 was found to have transmission bias in the family. Additionally, these variants were found to be associated with one or more of ASD-associated phenotypic traits. Multifactor dimensionality reduction (MDR) analyses showed mostly independent contributory effects of some of the variants. Again, the gene expression levels of GABRB3, GABRG3, and GABRA5 were downregulated in the cases than the controls. ForGABRA5 rs35399885, the CC genotypes corresponded to higher expression levels compared to the other groups. This study reveals that genetic variants of GABAA receptor subunit genes are significantly associated with ASD. No data for the mentioned variants are found in the population of West Bengal, India.
Collapse
Affiliation(s)
- Pallabi Adak
- Manovikas Biomedical Research and Diagnostic Centre, Manovikas Kendra Rehabilitation and Research Institute for the Handicapped, 700107, Kolkata, West Bengal, India
| | - Nilanjana Banerjee
- Manovikas Biomedical Research and Diagnostic Centre, Manovikas Kendra Rehabilitation and Research Institute for the Handicapped, 700107, Kolkata, West Bengal, India.
| | - Swagata Sinha
- Out Patient Department, Manovikas Kendra Rehabilitation and Research Institute for the Handicapped, 700107, Kolkata, West Bengal, India
| | - Apurba Kumar Bandyopadhyay
- Out Patient Department, Manovikas Kendra Rehabilitation and Research Institute for the Handicapped, 700107, Kolkata, West Bengal, India
| |
Collapse
|
7
|
Hui KK, Chater TE, Goda Y, Tanaka M. How Staying Negative Is Good for the (Adult) Brain: Maintaining Chloride Homeostasis and the GABA-Shift in Neurological Disorders. Front Mol Neurosci 2022; 15:893111. [PMID: 35875665 PMCID: PMC9305173 DOI: 10.3389/fnmol.2022.893111] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/10/2022] [Indexed: 01/27/2023] Open
Abstract
Excitatory-inhibitory (E-I) imbalance has been shown to contribute to the pathogenesis of a wide range of neurodevelopmental disorders including autism spectrum disorders, epilepsy, and schizophrenia. GABA neurotransmission, the principal inhibitory signal in the mature brain, is critically coupled to proper regulation of chloride homeostasis. During brain maturation, changes in the transport of chloride ions across neuronal cell membranes act to gradually change the majority of GABA signaling from excitatory to inhibitory for neuronal activation, and dysregulation of this GABA-shift likely contributes to multiple neurodevelopmental abnormalities that are associated with circuit dysfunction. Whilst traditionally viewed as a phenomenon which occurs during brain development, recent evidence suggests that this GABA-shift may also be involved in neuropsychiatric disorders due to the “dematuration” of affected neurons. In this review, we will discuss the cell signaling and regulatory mechanisms underlying the GABA-shift phenomenon in the context of the latest findings in the field, in particular the role of chloride cotransporters NKCC1 and KCC2, and furthermore how these regulatory processes are altered in neurodevelopmental and neuropsychiatric disorders. We will also explore the interactions between GABAergic interneurons and other cell types in the developing brain that may influence the GABA-shift. Finally, with a greater understanding of how the GABA-shift is altered in pathological conditions, we will briefly outline recent progress on targeting NKCC1 and KCC2 as a therapeutic strategy against neurodevelopmental and neuropsychiatric disorders associated with improper chloride homeostasis and GABA-shift abnormalities.
Collapse
Affiliation(s)
- Kelvin K. Hui
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, United States
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY, United States
- *Correspondence: Kelvin K. Hui,
| | - Thomas E. Chater
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
- Thomas E. Chater,
| | - Yukiko Goda
- Laboratory for Synaptic Plasticity and Connectivity, RIKEN Center for Brain Science, Wako, Japan
- Synapse Biology Unit, Okinawa Institute for Science and Technology Graduate University, Onna, Japan
| | - Motomasa Tanaka
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Japan
| |
Collapse
|
8
|
Cavaliere S, Lori S, Bastianelli M, Cossu C, Gabbanini S, Dani C, Bertini G. Unilateral Transient Enhanced SEP during Integrated Multiparameter Neurophysiological Monitoring in a Newborn with Symptomatic Seizure. Pediatr Rep 2022; 14:254-261. [PMID: 35736655 PMCID: PMC9230835 DOI: 10.3390/pediatric14020033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 05/05/2022] [Accepted: 05/24/2022] [Indexed: 02/01/2023] Open
Abstract
During Integrated Multiparametric Neurophysiological Monitoring (IMNA), a newborn with suspected hypoxia at birth and microhaemorrhagic and ischaemic lesions presented some clonic-tonic episodes with specific EEG patterns characterized by rolandic and temporal spikes and the appearance of a unilateral enhanced Somatosensory Evoked Potential (SEP) (10.45 µv). Since the literature does not seem to describe cases of giant SEP in newborns, in this case report, we will discuss the hypotheses underlying this potential. It could be assumed that the ischaemic and haemorrhagic lesions presented by the newborn may have developed as a result of neurotransmitter balance failure. This may be the origin of the EEG picture, which, consequently, could have triggered a potential with high amplitude.
Collapse
Affiliation(s)
- Sara Cavaliere
- Department of Neurosciences, Psychology, Drug Research and Children’s Health, University of Florence, 50134 Florence, Italy; (S.C.); (C.D.)
| | - Silvia Lori
- Neurophysiology Unit, Neuro-Musculo-Skeletal Department, Careggi University Hospital, 50134 Florence, Italy; (S.L.); (M.B.); (C.C.); (S.G.)
| | - Maria Bastianelli
- Neurophysiology Unit, Neuro-Musculo-Skeletal Department, Careggi University Hospital, 50134 Florence, Italy; (S.L.); (M.B.); (C.C.); (S.G.)
| | - Cesarina Cossu
- Neurophysiology Unit, Neuro-Musculo-Skeletal Department, Careggi University Hospital, 50134 Florence, Italy; (S.L.); (M.B.); (C.C.); (S.G.)
| | - Simonetta Gabbanini
- Neurophysiology Unit, Neuro-Musculo-Skeletal Department, Careggi University Hospital, 50134 Florence, Italy; (S.L.); (M.B.); (C.C.); (S.G.)
| | - Carlo Dani
- Department of Neurosciences, Psychology, Drug Research and Children’s Health, University of Florence, 50134 Florence, Italy; (S.C.); (C.D.)
| | - Giovanna Bertini
- Department of Neurosciences, Psychology, Drug Research and Children’s Health, University of Florence, 50134 Florence, Italy; (S.C.); (C.D.)
- Correspondence:
| |
Collapse
|
9
|
Cossart R, Garel S. Step by step: cells with multiple functions in cortical circuit assembly. Nat Rev Neurosci 2022; 23:395-410. [DOI: 10.1038/s41583-022-00585-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2022] [Indexed: 12/23/2022]
|
10
|
Xing W, de Lima AD, Voigt T. The Structural E/I Balance Constrains the Early Development of Cortical Network Activity. Front Cell Neurosci 2021; 15:687306. [PMID: 34349623 PMCID: PMC8326976 DOI: 10.3389/fncel.2021.687306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/17/2021] [Indexed: 01/03/2023] Open
Abstract
Neocortical networks have a characteristic constant ratio in the number of glutamatergic projection neurons (PN) and GABAergic interneurons (IN), and deviations in this ratio are often associated with developmental neuropathologies. Cultured networks with defined cellular content allowed us to ask if initial PN/IN ratios change the developmental population dynamics, and how different ratios impact the physiological excitatory/inhibitory (E/I) balance and the network activity development. During the first week in vitro, the IN content modulated PN numbers, increasing their proliferation in networks with higher IN proportions. The proportion of INs in each network set remained similar to the initial plating ratio during the 4 weeks cultivation period. Results from additional networks generated with more diverse cellular composition, including early-born GABA neurons, suggest that a GABA-dependent mechanism may decrease the survival of additional INs. A large variation of the PN/IN ratio did not change the balance between isolated spontaneous glutamatergic and GABAergic postsynaptic currents charge transfer (E/I balance) measured in PNs or INs. In contrast, the E/I balance of multisynaptic bursts reflected differences in IN content. Additionally, the spontaneous activity recorded by calcium imaging showed that higher IN ratios were associated with increased frequency of network bursts combined with a decrease of participating neurons per event. In the 4th week in vitro, bursting activity was stereotypically synchronized in networks with very few INs but was more desynchronized in networks with higher IN proportions. These results suggest that the E/I balance of isolated postsynaptic currents in single cells may be regulated independently of PN/IN proportions, but the network bursts E/I balance and the maturation of spontaneous network activity critically depends upon the structural PN/IN ratio.
Collapse
Affiliation(s)
- Wenxi Xing
- Medizinische Fakultät, Institut für Physiologie, Otto-von-Guericke Universität, Magdeburg, Germany
| | - Ana Dolabela de Lima
- Medizinische Fakultät, Institut für Physiologie, Otto-von-Guericke Universität, Magdeburg, Germany
| | - Thomas Voigt
- Medizinische Fakultät, Institut für Physiologie, Otto-von-Guericke Universität, Magdeburg, Germany
| |
Collapse
|
11
|
Abstract
In mammals, the selective transformation of transient experience into stored memory occurs in the hippocampus, which develops representations of specific events in the context in which they occur. In this review, we focus on the development of hippocampal circuits and the self-organized dynamics embedded within them since the latter critically support the role of the hippocampus in learning and memory. We first discuss evidence that adult hippocampal cells and circuits are sculpted by development as early as during embryonic neurogenesis. We argue that these primary developmental programs provide a scaffold onto which later experience of the external world can be grafted. Next, we review the different sequences in the development of hippocampal cells and circuits at anatomical and functional levels. We cover a period extending from neurogenesis and migration to the appearance of phenotypic diversity within hippocampal cells, and their wiring into functional networks. We describe the progressive emergence of network dynamics in the hippocampus, from sensorimotor-driven early sharp waves to sequences of place cells tracking relational information. We outline the critical turn points and discontinuities in that developmental journey, and close by formulating open questions. We propose that rewinding the process of hippocampal development helps understand the main organization principles of memory circuits.
Collapse
Affiliation(s)
- Rosa Cossart
- Inserm, INMED, Turing Center for Living Systems, Aix Marseille University, Marseille, France
| | - Rustem Khazipov
- Inserm, INMED, Turing Center for Living Systems, Aix Marseille University, Marseille, France.,Laboratory of Neurobiology, Kazan Federal University, Kazan Russia
| |
Collapse
|
12
|
Electrophysiology of ionotropic GABA receptors. Cell Mol Life Sci 2021; 78:5341-5370. [PMID: 34061215 PMCID: PMC8257536 DOI: 10.1007/s00018-021-03846-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/02/2021] [Accepted: 04/23/2021] [Indexed: 10/30/2022]
Abstract
GABAA receptors are ligand-gated chloride channels and ionotropic receptors of GABA, the main inhibitory neurotransmitter in vertebrates. In this review, we discuss the major and diverse roles GABAA receptors play in the regulation of neuronal communication and the functioning of the brain. GABAA receptors have complex electrophysiological properties that enable them to mediate different types of currents such as phasic and tonic inhibitory currents. Their activity is finely regulated by membrane voltage, phosphorylation and several ions. GABAA receptors are pentameric and are assembled from a diverse set of subunits. They are subdivided into numerous subtypes, which differ widely in expression patterns, distribution and electrical activity. Substantial variations in macroscopic neural behavior can emerge from minor differences in structure and molecular activity between subtypes. Therefore, the diversity of GABAA receptors widens the neuronal repertoire of responses to external signals and contributes to shaping the electrical activity of neurons and other cell types.
Collapse
|
13
|
Basu SK, Pradhan S, du Plessis AJ, Ben-Ari Y, Limperopoulos C. GABA and glutamate in the preterm neonatal brain: In-vivo measurement by magnetic resonance spectroscopy. Neuroimage 2021; 238:118215. [PMID: 34058332 PMCID: PMC8404144 DOI: 10.1016/j.neuroimage.2021.118215] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/30/2021] [Accepted: 05/25/2021] [Indexed: 12/11/2022] Open
Abstract
Cognitive and behavioral disabilities in preterm infants, even without obvious brain injury on conventional neuroimaging, underscores a critical need to identify the subtle underlying microstructural and biochemical derangements. The gamma-aminobutyric acid (GABA) and glutamatergic neurotransmitter systems undergo rapid maturation during the crucial late gestation and early postnatal life, and are at-risk of disruption after preterm birth. Animal and human autopsy studies provide the bulk of current understanding since non-invasive specialized proton magnetic resonance spectroscopy (1H-MRS) to measure GABA and glutamate are not routinely available for this vulnerable population due to logistical and technical challenges. We review the specialized 1H-MRS techniques including MEscher-GArwood Point Resolved Spectroscopy (MEGA-PRESS), special challenges and considerations needed for interpretation of acquired data from the developing brain of preterm infants. We summarize the limited in-vivo preterm data, highlight the gaps in knowledge, and discuss future directions for optimal integration of available in-vivo approaches to understand the influence of GABA and glutamate on neurodevelopmental outcomes after preterm birth.
Collapse
Affiliation(s)
- Sudeepta K Basu
- Neonatology, Children's National Hospital, Washington, D.C., United States; Center for the Developing Brain, Children's National Hospital, Washington, D.C., United States; Division of Neurology, Children's National Hospital, Washington, D.C., United States; The George Washington University School of Medicine, Washington, D.C., United States
| | - Subechhya Pradhan
- Center for the Developing Brain, Children's National Hospital, Washington, D.C., United States; Division of Neurology, Children's National Hospital, Washington, D.C., United States; The George Washington University School of Medicine, Washington, D.C., United States
| | - Adre J du Plessis
- Fetal Medicine institute, Children's National Hospital, Washington, D.C., United States; Division of Neurology, Children's National Hospital, Washington, D.C., United States; The George Washington University School of Medicine, Washington, D.C., United States
| | - Yehezkel Ben-Ari
- Division of Neurology, Children's National Hospital, Washington, D.C., United States; Neurochlore, Marseille, France
| | - Catherine Limperopoulos
- Center for the Developing Brain, Children's National Hospital, Washington, D.C., United States; Division of Diagnostic Imaging and Radiology, Children's National Hospital, Washington, D.C., United States; Division of Neurology, Children's National Hospital, Washington, D.C., United States; The George Washington University School of Medicine, Washington, D.C., United States.
| |
Collapse
|
14
|
Peerboom C, Wierenga CJ. The postnatal GABA shift: A developmental perspective. Neurosci Biobehav Rev 2021; 124:179-192. [PMID: 33549742 DOI: 10.1016/j.neubiorev.2021.01.024] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 01/13/2021] [Accepted: 01/28/2021] [Indexed: 12/13/2022]
Abstract
GABA is the major inhibitory neurotransmitter that counterbalances excitation in the mature brain. The inhibitory action of GABA relies on the inflow of chloride ions (Cl-), which hyperpolarizes the neuron. In early development, GABA signaling induces outward Cl- currents and is depolarizing. The postnatal shift from depolarizing to hyperpolarizing GABA is a pivotal event in brain development and its timing affects brain function throughout life. Altered timing of the postnatal GABA shift is associated with several neurodevelopmental disorders. Here, we argue that the postnatal shift from depolarizing to hyperpolarizing GABA represents the final shift in a sequence of GABA shifts, regulating proliferation, migration, differentiation, and finally plasticity of developing neurons. Each developmental GABA shift ensures that the instructive role of GABA matches the circumstances of the developing network. Sensory input may be a crucial factor in determining proper timing of the postnatal GABA shift. A developmental perspective is necessary to interpret the full consequences of a mismatch between connectivity, activity and GABA signaling during brain development.
Collapse
Affiliation(s)
- Carlijn Peerboom
- Cell Biology, Neurobiology and Biophysics, Biology Department, Faculty of Science, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Corette J Wierenga
- Cell Biology, Neurobiology and Biophysics, Biology Department, Faculty of Science, Utrecht University, 3584 CH, Utrecht, the Netherlands.
| |
Collapse
|
15
|
Abstract
Retinal ganglion cells (RGCs) serve as a crucial communication channel from the retina to the brain. In the adult, these cells receive input from defined sets of presynaptic partners and communicate with postsynaptic brain regions to convey features of the visual scene. However, in the developing visual system, RGC interactions extend beyond their synaptic partners such that they guide development before the onset of vision. In this Review, we summarize our current understanding of how interactions between RGCs and their environment influence cellular targeting, migration and circuit maturation during visual system development. We describe the roles of RGC subclasses in shaping unique developmental responses within the retina and at central targets. Finally, we highlight the utility of RNA sequencing and genetic tools in uncovering RGC type-specific roles during the development of the visual system.
Collapse
Affiliation(s)
- Shane D'Souza
- The Visual Systems Group, Cincinnati Children's Hospital, Cincinnati, OH 45229, USA
- Center for Chronobiology, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital, Cincinnati, OH 45229, USA
- Molecular and Developmental Biology Graduate Program, University of Cincinnati, College of Medicine, Cincinnati, OH 45229, USA
| | - Richard A Lang
- The Visual Systems Group, Cincinnati Children's Hospital, Cincinnati, OH 45229, USA
- Center for Chronobiology, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital, Cincinnati, OH 45229, USA
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH 45229, USA
- Department of Ophthalmology, University of Cincinnati, College of Medicine, Cincinnati, OH 45229, USA
| |
Collapse
|
16
|
Melikishvili G, Dulac O, Gataullina S. Neonatal SCN2A encephalopathy: A peculiar recognizable electroclinical sequence. Epilepsy Behav 2020; 111:107187. [PMID: 32603808 DOI: 10.1016/j.yebeh.2020.107187] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Sodium voltage-gated channel alpha subunit 2 (SCN2A) gene encodes the Nav1.2 subunit of voltage-gated sodium channel in pyramidal neurons. SCN2A gain-of-function mutations are identified more and more often with gene panels and whole exome sequencing. Phenotype ranges from benign neonatal or infantile seizures to severe epileptic encephalopathy. Although large series of patients targeting genetic background point out two main phenotypes with SCN2A encephalopathy, Ohtahara syndrome and malignant migrating partial seizures in infancy (EMPSI), we noticed that in fact, a peculiar clinical and electroencephalogram (EEG) sequence distinct from these syndromes should suggest the diagnosis early. PATIENTS AND METHODS We report three new cases with de novo SCN2A mutations - 166237617C>A p.(Asp1487Glu), c.407T>G p.(Met136Arg), and c.4633A>G p.(Met1545Val) - diagnosed by direct sequencing or genes panel, their follow-up ranging from 4 to 5 years. RESULTS For all three patients, seizures started at two days of life and consisted of apnea and cyanosis with partial clonic or tonic, alternating on both sides with, up to 100/day, evolving to generalized tonic-clonic seizures (GTCS) and epileptic spasms by three months. First EEG showed a discontinuous pattern, evolving to multifocal spikes, by 3 (two patients) and 6 months (one). Seizure frequency decreased progressively by the middle or end of the first year of life. Only less frequent GTCS persisted during the second year of life for two patients. Improvement was observed in two patients with sodium channel blocker (phenytoin) used at age of 1 month for one patient and at 2 years for another one. All patients remained with severe psychomotor delay. DISCUSSION All three infants share a condition different from Ohtahara syndrome in which tonic spasms predominate and suppression-burst pattern is obvious, and from EMPSI, in which partial migrating discharges involve successively the various parts of the brain including occipital regions with oculoclonic seizures, but there is neither discontinuous pattern nor therapeutic response to sodium channel blockers. CONCLUSION Neonatal SCN2A encephalopathy has a recognizable phenotype starting soon after birth with alternating partial motor seizures evolving to infantile spasms and a discontinuous EEG pattern. Seizures improve spontaneously in the first year of life. This electroclinical sequence should indicate the search of SCN2A mutation and suggest the administration of sodium channel blockers.
Collapse
Affiliation(s)
- Gia Melikishvili
- Department of Pediatrics, MediClubGeorgia Medical Center, Tbilisi, Georgia
| | | | - Svetlana Gataullina
- Services d'explorations fonctionnelles, Centre de médecine du sommeil, Hôpital Antoine-Béclère, AP-HP, Clamart, France; Service de pédiatrie, Centre hospitalier intercommunal André Grégoire, Montreuil, France.
| |
Collapse
|
17
|
Kostović I. The enigmatic fetal subplate compartment forms an early tangential cortical nexus and provides the framework for construction of cortical connectivity. Prog Neurobiol 2020; 194:101883. [PMID: 32659318 DOI: 10.1016/j.pneurobio.2020.101883] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 06/05/2020] [Accepted: 07/06/2020] [Indexed: 12/19/2022]
Abstract
The most prominent transient compartment of the primate fetal cortex is the deep, cell-sparse, synapse-containing subplate compartment (SPC). The developmental role of the SPC and its extraordinary size in humans remain enigmatic. This paper evaluates evidence on the development and connectivity of the SPC and discusses its role in the pathogenesis of neurodevelopmental disorders. A synthesis of data shows that the subplate becomes a prominent compartment by its expansion from the deep cortical plate (CP), appearing well-delineated on MR scans and forming a tangential nexus across the hemisphere, consisting of an extracellular matrix, randomly distributed postmigratory neurons, multiple branches of thalamic and long corticocortical axons. The SPC generates early spontaneous non-synaptic and synaptic activity and mediates cortical response upon thalamic stimulation. The subplate nexus provides large-scale interareal connectivity possibly underlying fMR resting-state activity, before corticocortical pathways are established. In late fetal phase, when synapses appear within the CP, transient the SPC coexists with permanent circuitry. The histogenetic role of the SPC is to provide interactive milieu and capacity for guidance, sorting, "waiting" and target selection of thalamocortical and corticocortical pathways. The new evolutionary role of the SPC and its remnant white matter neurons is linked to the increasing number of associative pathways in the human neocortex. These roles attributed to the SPC are regulated using a spatiotemporal gene expression during critical periods, when pathogenic factors may disturb vulnerable circuitry of the SPC, causing neurodevelopmental cognitive circuitry disorders.
Collapse
Affiliation(s)
- Ivica Kostović
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Scientific Centre of Excellence for Basic, Clinical and Translational Neuroscience, Salata 12, 10000 Zagreb, Croatia.
| |
Collapse
|
18
|
Ovsepian SV, O'Leary VB, Vesselkin NP. Evolutionary origins of chemical synapses. VITAMINS AND HORMONES 2020; 114:1-21. [PMID: 32723540 DOI: 10.1016/bs.vh.2020.04.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Synaptic transmission is a fundamental neurobiological process by which neurons interact with each other and non-neuronal cells. It involves release of active substances from the presynaptic neuron onto receptive elements of postsynaptic cells, inducing waves of spreading electrochemical response. While much has been learned about the cellular and molecular mechanisms driving and governing transmitter release and sensing, the evolutionary origin of synaptic connections remains obscure. Herein, we review emerging evidence and concepts suggesting that key components of chemical synapse arose independently from neurons, in different functional and biological contexts, before the rise of multicellular living forms. We argue that throughout evolution, distinct synaptic constituents have been co-opted from ancestral forms for a new role in early metazoan, leading to the rise of chemical synapses and neurotransmission. Such a mosaic model of the origin of chemical synapses agrees with and supports the pluralistic hypothesis of evolutionary change.
Collapse
Affiliation(s)
- Saak V Ovsepian
- Institute for Biological and Medical Imaging, Helmholtz Zentrum Munich, German Research Center for Environmental Health, Neuherberg, Germany; International Centre for Neurotherapeutics, Dublin City University, Dublin, Ireland; Department of Experimental Neurobiology, National Institute of Mental Health, Klecany, Czech Republic; Department of Psychiatry and Medical Psychology, 3rd Faculty of Medicine of Charles University, Prague, Czech Republic.
| | - Valerie B O'Leary
- Department of Medical Genetics, Third Faculty of Medicine, Charles University, Ruská, Czech Republic
| | - Nikolai P Vesselkin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia; Faculty of Medicine, The State University of Saint Petersburg, St. Petersburg, Russia
| |
Collapse
|
19
|
Ojeda J, Ávila A. Early Actions of Neurotransmitters During Cortex Development and Maturation of Reprogrammed Neurons. Front Synaptic Neurosci 2019; 11:33. [PMID: 31824293 PMCID: PMC6881277 DOI: 10.3389/fnsyn.2019.00033] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/07/2019] [Indexed: 12/12/2022] Open
Abstract
The development of the brain is shaped by a myriad of factors among which neurotransmitters play remarkable roles before and during the formation and maturation of synaptic circuits. Cellular processes such as neurogenesis, morphological development, synaptogenesis and maturation of synapses are temporary and spatially regulated by the local or distal influence of neurotransmitters in the developing cortex. Thus, research on this area has contributed to the understanding of fundamental mechanisms of brain development and to shed light on the etiology of various human neurodevelopmental disorders such as autism and Rett syndrome (RTT), among others. Recently, the field of neuroscience has been shaken by an explosive advance of experimental approaches linked to the use of induced pluripotent stem cells and reprogrammed neurons. This new technology has allowed researchers for the first time to model in the lab the unique events that take place during early human brain development and to explore the mechanisms that cause synaptopathies. In this context, the role of neurotransmitters during early stages of cortex development is beginning to be re-evaluated and a revision of the state of the art has become necessary in a time when new protocols are being worked out to differentiate stem cells into functional neurons. New perspectives on reconsidering the function of neurotransmitters include opportunities for methodological advances, a better understanding of the origin of mental disorders and the potential for development of new treatments.
Collapse
Affiliation(s)
- Jorge Ojeda
- Developmental Neurobiology Unit, Biomedical Sciences Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Ariel Ávila
- Developmental Neurobiology Unit, Biomedical Sciences Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile
| |
Collapse
|
20
|
Chronic exercise buffers the cognitive dysfunction and decreases the susceptibility to seizures in PTZ-treated rats. Epilepsy Behav 2019; 98:173-187. [PMID: 31377659 DOI: 10.1016/j.yebeh.2019.07.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/02/2019] [Accepted: 07/08/2019] [Indexed: 02/02/2023]
Abstract
Epilepsy is a serious neurological disorder posing a severe burden to our society. Cognitive deficits are very common comorbidities of epilepsy. It is known that enhanced cognition has been demonstrated as an indicator for successful treatment of epilepsy. Physical exercise shows a positive consequence on cognition in healthy individuals and improves health and life conditions in people with epilepsy. However, there is no direct evidence to determine the role and the potential mechanism of physical exercise on the cognitive impairment and the relationship of susceptibility to seizures. The goal of the current investigation was to explore whether sustained physical exercise improves the cognitive dysfunction and simultaneously decreases the susceptibility to seizures in rats with epilepsy. Rats were treated with pentylenetetrazole (PTZ) (35 mg/kg, i.p. [intraperitoneally]) for 36 days to induce chronic epilepsy. During the induction period, rats were exposed to voluntary wheel running or forced swimming 30 min prior to each PTZ injection from the 16th day. The cognition of rats was evaluated by object recognition test and passive avoidance test. The susceptibility to seizures was evaluated by seizure frequency and duration. The levels of synaptic-related proteins including PSD95 (postsynaptic density 95), Synapsin, GluA1, and BDNF (brain-derived neurotrophic factor) were measured to evaluate the hippocampal synaptic plasticity. Furthermore, the GAD67 (glutamic acid decarboxylase) levels and GABA (γ-aminobutyric acid)ergic function in PTZ-treated rats were also determined. Finally, antagonist of GABAAR (GABAA receptors) bicuculline was used to explore the reversal effects of physical activity on seizures and cognition. The results showed that rats subjected to voluntary wheel running or forced swimming showed a significant reduction of seizure frequency and duration in PTZ-treated group relative to rats without running or swimming. In addition, both running and swimming improved cognitive function as measured by enhanced performance in object recognition test and passive avoidance test. Furthermore, the reduced levels of synaptic-related proteins and GABAergic function were reversed by exercise compared with rats without exercise. Moreover, antagonism of hippocampal CA3 (cornu ammonis 3) GABAergic neurons blocks the reversal effects of physical activity on seizures and cognition in PTZ-treated rats. These data showed that chronic physical exercise reduced the frequency of seizures and improved the cognitive function in a rat model of chronic epilepsy through normalization of CA3 synaptic plasticity and GABAergic function. Our findings suggest that chronic physical exercise has beneficial effects on controlling seizure through enhancement of cognition and highlights the possibility to translate into reduced seizure recurrence in people with epilepsy.
Collapse
|
21
|
Bekri A, Liao M, Drapeau P. Glycine Regulates Neural Stem Cell Proliferation During Development via Lnx1-Dependent Notch Signaling. Front Mol Neurosci 2019; 12:44. [PMID: 30833887 PMCID: PMC6387910 DOI: 10.3389/fnmol.2019.00044] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 02/01/2019] [Indexed: 11/28/2022] Open
Abstract
During development of the zebrafish embryo, glycine signaling promotes the differentiation of neural stem cells (NSCs). We found that glycine signaling suppresses the expression of Ligand of Numb X1 (lnx1, Ligand of numb protein-x1), a gene of unknown function during NSC differentiation that is selectively expressed in the embryonic central nervous system (CNS). As a consequence, Numb levels were stabilized and Notch activity (measured as her4.1 expression) was reduced, promoting NSC differentiation. These consequent actions were blocked by knockdown of lnx1. In contrast, lnx1 overexpression increased NSC proliferation and led to defects of neural tube closure at the early stages of development. Thus, our data provide evidence that glycine/lnx1 signaling modulates NSC proliferation by regulation of Notch signaling.
Collapse
Affiliation(s)
- Abdelhamid Bekri
- Research Center of the University of Montreal Hospital Center (CRCHUM), University of Montreal, Montreal, QC, Canada.,Department of Biochemistry, University of Montreal, Montreal, QC, Canada
| | - Meijiang Liao
- Research Center of the University of Montreal Hospital Center (CRCHUM), University of Montreal, Montreal, QC, Canada
| | - Pierre Drapeau
- Research Center of the University of Montreal Hospital Center (CRCHUM), University of Montreal, Montreal, QC, Canada.,Department of Neuroscience, University of Montreal, Montreal, QC, Canada
| |
Collapse
|
22
|
Carmona-Alcocer V, Rohr KE, Joye DAM, Evans JA. Circuit development in the master clock network of mammals. Eur J Neurosci 2018; 51:82-108. [PMID: 30402923 DOI: 10.1111/ejn.14259] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 10/08/2018] [Accepted: 10/31/2018] [Indexed: 12/24/2022]
Abstract
Daily rhythms are generated by the circadian timekeeping system, which is orchestrated by the master circadian clock in the suprachiasmatic nucleus (SCN) of mammals. Circadian timekeeping is endogenous and does not require exposure to external cues during development. Nevertheless, the circadian system is not fully formed at birth in many mammalian species and it is important to understand how SCN development can affect the function of the circadian system in adulthood. The purpose of the current review is to discuss the ontogeny of cellular and circuit function in the SCN, with a focus on work performed in model rodent species (i.e., mouse, rat, and hamster). Particular emphasis is placed on the spatial and temporal patterns of SCN development that may contribute to the function of the master clock during adulthood. Additional work aimed at decoding the mechanisms that guide circadian development is expected to provide a solid foundation upon which to better understand the sources and factors contributing to aberrant maturation of clock function.
Collapse
Affiliation(s)
| | - Kayla E Rohr
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
| | - Deborah A M Joye
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
| | - Jennifer A Evans
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
| |
Collapse
|
23
|
Meyer G, González-Gómez M. The heterogeneity of human Cajal-Retzius neurons. Semin Cell Dev Biol 2018; 76:101-111. [DOI: 10.1016/j.semcdb.2017.08.059] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 08/24/2017] [Accepted: 08/28/2017] [Indexed: 12/29/2022]
|
24
|
Al-Muhtasib N, Sepulveda-Rodriguez A, Vicini S, Forcelli PA. Neonatal phenobarbital exposure disrupts GABAergic synaptic maturation in rat CA1 neurons. Epilepsia 2018; 59:333-344. [PMID: 29315524 DOI: 10.1111/epi.13990] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2017] [Indexed: 01/24/2023]
Abstract
OBJECTIVE Phenobarbital is the most commonly utilized drug for the treatment of neonatal seizures. The use of phenobarbital continues despite growing evidence that it exerts suboptimal seizure control and is associated with long-term alterations in brain structure, function, and behavior. Alterations following neonatal phenobarbital exposure include acute induction of neuronal apoptosis, disruption of synaptic development in the striatum, and a host of behavioral deficits. These behavioral deficits include those in learning and memory mediated by the hippocampus. However, the synaptic changes caused by acute exposure to phenobarbital that lead to lasting effects on brain function and behavior remain understudied. METHODS Postnatal day (P)7 rat pups were treated with phenobarbital (75 mg/kg) or saline. On P13-14 or P29-37, acute slices were prepared and whole-cell patch-clamp recordings were made from CA1 pyramidal neurons. RESULTS At P14 we found an increase in miniature inhibitory postsynaptic current (mIPSC) frequency in the phenobarbital-exposed as compared to the saline-exposed group. In addition to this change in mIPSC frequency, the phenobarbital group displayed larger bicuculline-sensitive tonic currents, decreased capacitance and membrane time constant, and a surprising persistence of giant depolarizing potentials. At P29+, the frequency of mIPSCs in the saline-exposed group had increased significantly from the frequency at P14, typical of normal synaptic development; at this age the phenobarbital-exposed group displayed a lower mIPSC frequency than did the control group. Spontaneous inhibitory postsynaptic current (sIPSC) frequency was unaffected at either P14 or P29+. SIGNIFICANCE These neurophysiological alterations following phenobarbital exposure provide a potential mechanism by which acute phenobarbital exposure can have a long-lasting impact on brain development and behavior.
Collapse
Affiliation(s)
- Nour Al-Muhtasib
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC, USA
| | - Alberto Sepulveda-Rodriguez
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC, USA.,Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, USA
| | - Stefano Vicini
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC, USA.,Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, USA.,Department of Neuroscience, Georgetown University, Washington, DC, USA
| | - Patrick A Forcelli
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC, USA.,Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, USA.,Department of Neuroscience, Georgetown University, Washington, DC, USA
| |
Collapse
|
25
|
Dulka EA, Moenter SM. Prepubertal Development of Gonadotropin-Releasing Hormone Neuron Activity Is Altered by Sex, Age, and Prenatal Androgen Exposure. Endocrinology 2017; 158:3943-3953. [PMID: 28938422 PMCID: PMC5695838 DOI: 10.1210/en.2017-00768] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 09/12/2017] [Indexed: 11/19/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) neurons regulate reproduction though pulsatile hormone release. Disruption of GnRH release as measured via luteinizing hormone (LH) pulses occurs in polycystic ovary syndrome (PCOS), and in young hyperandrogenemic girls. In adult prenatally androgenized (PNA) mice, which exhibit many aspects of PCOS, increased LH is associated with increased GnRH neuron action potential firing. How GnRH neuron activity develops over the prepubertal period and whether this is altered by sex or prenatal androgen treatment are unknown. We hypothesized GnRH neurons are active before puberty and that this activity is sexually differentiated and altered by PNA. Dams were injected with dihydrotestosterone (DHT) on days 16 to 18 post copulation to generate PNA mice. Action potential firing of GFP-identified GnRH neurons in brain slices from 1-, 2-, 3-, and 4-week-old and adult mice was monitored. GnRH neurons were active at all ages tested. In control females, activity increased with age through 3 weeks, then decreased to adult levels. In contrast, activity did not change in PNA females and was reduced at 3 weeks. Activity was higher in control females than males from 2 to 3 weeks. PNA did not affect GnRH neuron firing rate in males at any age. Short-term action potential patterns were also affected by age and PNA treatment. GnRH neurons are thus typically more active during the prepubertal period than adulthood, and PNA reduces prepubertal activity in females. Prepubertal activity may play a role in establishing sexually differentiated neuronal networks upstream of GnRH neurons; androgen-induced changes during this time may contribute to the adult PNA, and possibly PCOS, phenotype.
Collapse
Affiliation(s)
- Eden A. Dulka
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109
| | - Suzanne M. Moenter
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan 48109
| |
Collapse
|
26
|
Pandit S, Lee GS, Park JB. Developmental changes in GABA A tonic inhibition are compromised by multiple mechanisms in preadolescent dentate gyrus granule cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 21:695-702. [PMID: 29200913 PMCID: PMC5709487 DOI: 10.4196/kjpp.2017.21.6.695] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 01/28/2023]
Abstract
The sustained tonic currents (Itonic) generated by γ-aminobutyric acid A receptors (GABAARs) are implicated in diverse age-dependent brain functions. While various mechanisms regulating Itonic in the hippocampus are known, their combined role in Itonic regulation is not well understood in different age groups. In this study, we demonstrated that a developmental increase in GABA transporter (GAT) expression, combined with gradual decrease in GABAAR α5 subunit, resulted in various Itonic in the dentate gyrus granule cells (DGGCs) of preadolescent rats. Both GAT-1 and GAT-3 expression gradually increased at infantile (P6-8 and P13-15) and juvenile (P20-22 and P27-29) stages, with stabilization observed thereafter in adolescents (P34-36) and young adults (P41-43). Itonic facilitation of a selective GAT-1 blocker (NO-711) was significantly less at P6-8 than after P13-15. The facilitation of Itonic by SNAP-5114, a GAT-3 inhibitor, was negligible in the absence of exogenous GABA at all tested ages. In contrast, Itonic in the presence of a nonselective GAT blocker (nipecotic acid, NPA) gradually decreased with age during the preadolescent period, which was mimicked by Itonic changes in the presence of exogenous GABA. Itonic sensitivity to L-655,708, a GABAAR α5 subunit inverse agonist, gradually decreased during the preadolescent period in the presence of NPA or exogenous GABA. Finally, Western blot analysis showed that the expression of the GABAAR α5 subunit in the dentate gyrus gradually decreased with age. Collectively, our results suggested that the Itonic regulation of altered GATs is under the final tune of GABAAR α5 subunit activation in DGGCs at different ages.
Collapse
Affiliation(s)
- Sudip Pandit
- Department of Physiology, School of Medicine and Brain Research Institute, Chungnam National University, Daejeon 35015, Korea
| | - Gyu Seung Lee
- Department of Physiology, School of Medicine and Brain Research Institute, Chungnam National University, Daejeon 35015, Korea
| | - Jin Bong Park
- Department of Physiology, School of Medicine and Brain Research Institute, Chungnam National University, Daejeon 35015, Korea
| |
Collapse
|
27
|
Erisgin Z, Ayas B, Nyengaard JR, Ercument Beyhun N, Terzi Y. The neurotoxic effects of prenatal gabapentin and oxcarbazepine exposure on newborn rats. J Matern Fetal Neonatal Med 2017; 32:461-471. [PMID: 28931341 DOI: 10.1080/14767058.2017.1383378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
AIM Teratogenicity is a problematic issue for pregnant women because of X-ray radiation, drugs, and genetic and unknown variables. First-generation antiepileptic drugs (AED) like valproic acid are well-known teratogens for developing fetuses. However, their usage is necessary in order to prevent maternal seizures. The underlying mechanism of birth defects associated with AED exposure remains unclear and information about the neurotoxic effects of prenatal exposure to AED is still limited. Oxcarbazepine (OXC) and gabapentin (GBP) are second-generation AED. It still remains unclear how much these drugs are safe during pregnancy. This study aimed to investigate whether any neurotoxic effect of OXC and GBP in utero exposure on the developing brain. METHODS Eighteen pregnant Wistar albino rats were divided into six groups. The first group was exposed to OXC at 100 mg/kg/day, the second to GBP at 50 mg/kg/day, and third to saline (0.9% NaCl) at 1.5 ml/day between the first and the fifth days of gestation. The same procedure was applied at the same dosages between the 6th and the 15th days of gestation for the 2nd three groups. Five female offspring (total n = 30, 45 days old) were taken from each group and stereological methods were applied in order to analyze the total and dopaminergic neuron number of the substantia nigra pars compacta (SNc). CONCLUSION The result is that the OXC and GBP exposure at different gestational periods may not give rise to congenital malformation and it appears that the GBP exposure during the organogenesis period proliferatively affects the total number of neurons.
Collapse
Affiliation(s)
- Zuleyha Erisgin
- a Department of Histology and Embryology , Giresun University, Faculty of Medicine , Giresun , Turkey
| | - Bulent Ayas
- b Department of Histology and Embryology , Ondokuz Mayıs University, Faculty of Medicine , Samsun , Turkey
| | - Jens R Nyengaard
- c Stereology and Electron Microscopy Laboratory , Aarhus University Hospital , Aarhus , Denmark
| | - N Ercument Beyhun
- d Department of Public Health , Black Sea Technical University, Faculty of Medicine , Trabzon , Turkey
| | - Yuksel Terzi
- e Department of Statistic, Faculty of Fine and Art , Ondokuz Mayıs University , Samsun , Turkey
| |
Collapse
|
28
|
Griguoli M, Cherubini E. Early Correlated Network Activity in the Hippocampus: Its Putative Role in Shaping Neuronal Circuits. Front Cell Neurosci 2017; 11:255. [PMID: 28878628 PMCID: PMC5572250 DOI: 10.3389/fncel.2017.00255] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/08/2017] [Indexed: 12/02/2022] Open
Abstract
Synchronized neuronal activity occurring at different developmental stages in various brain structures represents a hallmark of developmental circuits. This activity, which differs in its specific patterns among animal species may play a crucial role in de novo formation and in shaping neuronal networks. In the rodent hippocampus in vitro, the so-called giant depolarizing potentials (GDPs) constitute a primordial form of neuronal synchrony preceding more organized forms of activity such as oscillations in the theta and gamma frequency range. GDPs are generated at the network level by the interaction of the neurotransmitters glutamate and GABA which, immediately after birth, exert both a depolarizing and excitatory action on their targets. GDPs are triggered by GABAergic interneurons, which in virtue of their extensive axonal branching operate as functional hubs to synchronize large ensembles of cells. Intrinsic bursting activity, driven by a persistent sodium conductance and facilitated by the low expression of Kv7.2 and Kv7.3 channel subunits, responsible for IM, exerts a permissive role in GDP generation. Here, we discuss how GDPs are generated in a probabilistic way when neuronal excitability within a local circuit reaches a certain threshold and how GDP-associated calcium transients act as coincident detectors for enhancing synaptic strength at emerging GABAergic and glutamatergic synapses. We discuss the possible in vivo correlate of this activity. Finally, we debate recent data showing how, in several animal models of neuropsychiatric disorders including autism, a GDPs dysfunction is associated to morphological alterations of neuronal circuits and behavioral deficits reminiscent of those observed in patients.
Collapse
Affiliation(s)
- Marilena Griguoli
- European Brain Research Institute (EBRI) "Fondazione Rita Levi-Montalcini"Rome, Italy
| | - Enrico Cherubini
- European Brain Research Institute (EBRI) "Fondazione Rita Levi-Montalcini"Rome, Italy.,Department of Neuroscience, International School for Advanced StudiesTrieste, Italy
| |
Collapse
|
29
|
Meyer G, González-Gómez M. The Subpial Granular Layer and Transient Versus Persisting Cajal-Retzius Neurons of the Fetal Human Cortex. Cereb Cortex 2017; 28:2043-2058. [DOI: 10.1093/cercor/bhx110] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 04/18/2017] [Indexed: 12/20/2022] Open
Affiliation(s)
- Gundela Meyer
- Units of Anatomy (MGG) and Histology (GM), Department of Basic Medical Science, Faculty of Medicine, University of La Laguna, Tenerife, Spain
| | - Miriam González-Gómez
- Units of Anatomy (MGG) and Histology (GM), Department of Basic Medical Science, Faculty of Medicine, University of La Laguna, Tenerife, Spain
| |
Collapse
|
30
|
Trabelsi Y, Amri M, Becq H, Molinari F, Aniksztejn L. The conversion of glutamate by glutamine synthase in neocortical astrocytes from juvenile rat is important to limit glutamate spillover and peri/extrasynaptic activation of NMDA receptors. Glia 2016; 65:401-415. [PMID: 27862359 DOI: 10.1002/glia.23099] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 12/31/2022]
Abstract
Glutamate transporters (EAATs) are important to maintain spatial and temporal specificity of synaptic transmission. Their efficiency to uptake and transport glutamate into the intracellular space depends on several parameters including the intracellular concentrations of Na+ and glutamate, the elevations of which may slow down the cycling rate of EAATs. In astrocytes, glutamate is maintained at low concentration due to the presence of specific enzymes such as glutamine synthase (GS). GS inhibition results in cytosolic accumulation of glutamate suggesting that the conversion of glutamate by GS is important for EAATs operation. Here we recorded astrocytes from juvenile rat neocortical slices and analyzed the consequences of elevated intracellular glutamate concentrations and of GS inhibition on the time course of synaptically evoked transporter current (STC). In slices from rats treated with methionine sulfoximine (MSO), a GS inhibitor, STC evoked by short burst of high frequency stimulation (HFS; 100 Hz for 100 ms) but not by low frequency stimulation (LFS; 0.1 Hz) was twice slower than STC evoked from saline injected rats. Same results were obtained for astrocytes recorded with pipette containing 3-10 mM glutamate and compared with cells recorded with 0 or1 mM glutamate in the patch pipette. We also showed that HFS elicited significantly larger NMDAR-excitatory postsynaptic currents (EPSCs) with a stronger peri/extrasynaptic component in pyramidal cells from MSO-treated compared with saline treated rats. Taken together our data demonstrate that the conversion of glutamate by GS is fundamental to ensure an efficient clearance of glutamate by EAATs and to prevent glutamate spillover. GLIA 2017;65:401-415.
Collapse
Affiliation(s)
- Yosra Trabelsi
- Institut de Neurobiologie de la Méditerranée (INMED), Aix-Marseille Université, Marseille, 13009, France.,INSERM, UMR_S 901, Marseille, 13009, France
| | - Mohamed Amri
- Laboratoire de Neurophysiologie Fonctionnelle et Pathologies, Tunis, UR11ES09, Tunisie
| | - Hélène Becq
- Institut de Neurobiologie de la Méditerranée (INMED), Aix-Marseille Université, Marseille, 13009, France.,INSERM, UMR_S 901, Marseille, 13009, France
| | - Florence Molinari
- Institut de Neurobiologie de la Méditerranée (INMED), Aix-Marseille Université, Marseille, 13009, France.,INSERM, UMR_S 901, Marseille, 13009, France
| | - Laurent Aniksztejn
- Institut de Neurobiologie de la Méditerranée (INMED), Aix-Marseille Université, Marseille, 13009, France.,INSERM, UMR_S 901, Marseille, 13009, France
| |
Collapse
|
31
|
Momose-Sato Y, Sato K. Development of Spontaneous Activity in the Avian Hindbrain. Front Neural Circuits 2016; 10:63. [PMID: 27570506 PMCID: PMC4981603 DOI: 10.3389/fncir.2016.00063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 07/29/2016] [Indexed: 11/13/2022] Open
Abstract
Spontaneous activity in the developing central nervous system occurs before the brain responds to external sensory inputs, and appears in the hindbrain and spinal cord as rhythmic electrical discharges of cranial and spinal nerves. This spontaneous activity recruits a large population of neurons and propagates like a wave over a wide region of the central nervous system. Here, we review spontaneous activity in the chick hindbrain by focusing on this large-scale synchronized activity. Asynchronous activity that is expressed earlier than the above mentioned synchronized activity and activity originating in midline serotonergic neurons are also briefly mentioned.
Collapse
Affiliation(s)
- Yoko Momose-Sato
- Department of Nutrition and Dietetics, College of Nutrition, Kanto Gakuin University Yokohama, Japan
| | - Katsushige Sato
- Department of Health and Nutrition Sciences, Faculty of Human Health, Komazawa Women's University Tokyo, Japan
| |
Collapse
|
32
|
Genetic and functional analyses demonstrate a role for abnormal glycinergic signaling in autism. Mol Psychiatry 2016; 21:936-45. [PMID: 26370147 PMCID: PMC5382231 DOI: 10.1038/mp.2015.139] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 06/09/2015] [Accepted: 08/10/2015] [Indexed: 02/08/2023]
Abstract
Autism spectrum disorder (ASD) is a common neurodevelopmental condition characterized by marked genetic heterogeneity. Recent studies of rare structural and sequence variants have identified hundreds of loci involved in ASD, but our knowledge of the overall genetic architecture and the underlying pathophysiological mechanisms remains incomplete. Glycine receptors (GlyRs) are ligand-gated chloride channels that mediate inhibitory neurotransmission in the adult nervous system but exert an excitatory action in immature neurons. GlyRs containing the α2 subunit are highly expressed in the embryonic brain, where they promote cortical interneuron migration and the generation of excitatory projection neurons. We previously identified a rare microdeletion of the X-linked gene GLRA2, encoding the GlyR α2 subunit, in a boy with autism. The microdeletion removes the terminal exons of the gene (GLRA2(Δex8-9)). Here, we sequenced 400 males with ASD and identified one de novo missense mutation, p.R153Q, absent from controls. In vitro functional analysis demonstrated that the GLRA2(Δex8)(-)(9) protein failed to localize to the cell membrane, while the R153Q mutation impaired surface expression and markedly reduced sensitivity to glycine. Very recently, an additional de novo missense mutation (p.N136S) was reported in a boy with ASD, and we show that this mutation also reduced cell-surface expression and glycine sensitivity. Targeted glra2 knockdown in zebrafish induced severe axon-branching defects, rescued by injection of wild type but not GLRA2(Δex8-9) or R153Q transcripts, providing further evidence for their loss-of-function effect. Glra2 knockout mice exhibited deficits in object recognition memory and impaired long-term potentiation in the prefrontal cortex. Taken together, these results implicate GLRA2 in non-syndromic ASD, unveil a novel role for GLRA2 in synaptic plasticity and learning and memory, and link altered glycinergic signaling to social and cognitive impairments.
Collapse
|
33
|
Glutamate signalling: A multifaceted modulator of oligodendrocyte lineage cells in health and disease. Neuropharmacology 2016; 110:574-585. [PMID: 27346208 DOI: 10.1016/j.neuropharm.2016.06.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 05/27/2016] [Accepted: 06/16/2016] [Indexed: 01/10/2023]
Abstract
Myelin is essential for the mammalian brain to function efficiently. Whilst many factors have been associated with regulating the differentiation of oligodendroglia and myelination, glutamate signalling might be particularly important for learning-dependent myelination. The majority of myelinated projection neurons are glutamatergic. Oligodendrocyte precursor cells receive glutamatergic synaptic inputs from unmyelinated axons and oligodendrocyte lineage cells express glutamate receptors which enable them to monitor and respond to changes in neuronal activity. Yet, what role glutamate plays for oligodendroglia is not fully understood. Here, we review glutamate signalling and its effects on oligodendrocyte lineage cells, and myelination in health and disease. Furthermore, we discuss whether glutamate signalling between neurons and oligodendroglia might lay the foundation to activity-dependent white matter plasticity. This article is part of the Special Issue entitled 'Oligodendrocytes in Health and Disease'.
Collapse
|
34
|
Toth AB, Shum AK, Prakriya M. Regulation of neurogenesis by calcium signaling. Cell Calcium 2016; 59:124-34. [PMID: 27020657 DOI: 10.1016/j.ceca.2016.02.011] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/17/2016] [Accepted: 02/18/2016] [Indexed: 12/22/2022]
Abstract
Calcium (Ca(2+)) signaling has essential roles in the development of the nervous system from neural induction to the proliferation, migration, and differentiation of neural cells. Ca(2+) signaling pathways are shaped by interactions among metabotropic signaling cascades, intracellular Ca(2+) stores, ion channels, and a multitude of downstream effector proteins that activate specific genetic programs. The temporal and spatial dynamics of Ca(2+) signals are widely presumed to control the highly diverse yet specific genetic programs that establish the complex structures of the adult nervous system. Progress in the last two decades has led to significant advances in our understanding of the functional architecture of Ca(2+) signaling networks involved in neurogenesis. In this review, we assess the literature on the molecular and functional organization of Ca(2+) signaling networks in the developing nervous system and its impact on neural induction, gene expression, proliferation, migration, and differentiation. Particular emphasis is placed on the growing evidence for the involvement of store-operated Ca(2+) release-activated Ca(2+) (CRAC) channels in these processes.
Collapse
Affiliation(s)
- Anna B Toth
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Andrew K Shum
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, United States.
| |
Collapse
|
35
|
Pangratz-Fuehrer S, Sieghart W, Rudolph U, Parada I, Huguenard JR. Early postnatal switch in GABAA receptor α-subunits in the reticular thalamic nucleus. J Neurophysiol 2015; 115:1183-95. [PMID: 26631150 DOI: 10.1152/jn.00905.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 12/02/2015] [Indexed: 01/25/2023] Open
Abstract
The GABAergic neurons of the thalamic reticular nucleus (nRt) provide the primary source of inhibition within the thalamus. Using physiology, pharmacology, and immunohistochemistry in mice, we characterized postsynaptic developmental changes in these inhibitory projection neurons. First, at postnatal days 3-5 (P3-5), inhibitory postsynaptic currents (IPSCs) decayed very slowly, followed by a biphasic developmental progression, becoming faster at P6-8 and then slower again at P9-11 before stabilizing in a mature form around P12. Second, the pharmacological profile of GABA(A) receptor (GABA(A)R)-mediated IPSCs differed between neonatal and mature nRt neurons, and this was accompanied by reciprocal changes in α3 (late) and α5 (early) subunit expression in nRt. Zolpidem, selective for α1- and α3-containing GABA(A)Rs, augmented only mature IPSCs, whereas clonazepam enhanced IPSCs at all stages. This effect was blocked by the α5-specific inverse agonist L-655,708, but only in immature neurons. In α3(H126R) mice, in which α3-subunits were mutated to become benzodiazepine insensitive, IPSCs were enhanced compared with those in wild-type animals in early development. Third, tonic GABA(A)R activation in nRt is age dependent and more prominent in immature neurons, which correlates with early expression of α5-containing GABA(A)Rs. Thus neonatal nRt neurons show relatively high expression of α5-subunits, which contributes to both slow synaptic and tonic extrasynaptic inhibition. The postnatal switch in GABA(A)R subunits from α5 to α3 could facilitate spontaneous network activity in nRt that occurs at this developmental time point and which is proposed to play a role in early circuit development.
Collapse
Affiliation(s)
- Susanne Pangratz-Fuehrer
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California
| | - Werner Sieghart
- Brain Research Institute Vienna, University of Vienna, Vienna, Austria; and
| | - Uwe Rudolph
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Mailman Research Center, Harvard Medical School, Belmont, Massachusetts
| | - Isabel Parada
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California
| | - John R Huguenard
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California;
| |
Collapse
|
36
|
Akita T, Kumada T, Yoshihara SI, Egea J, Yamagishi S. Ion channels, guidance molecules, intracellular signaling and transcription factors regulating nervous and vascular system development. J Physiol Sci 2015; 66:175-88. [PMID: 26507418 PMCID: PMC4752580 DOI: 10.1007/s12576-015-0416-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 09/30/2015] [Indexed: 01/13/2023]
Abstract
Our sophisticated thoughts and behaviors are based on the miraculous development of our complex nervous network system, in which many different types of proteins and signaling cascades are regulated in a temporally and spatially ordered manner. Here we review our recent attempts to grasp the principles of nervous system development in terms of general cellular phenomena and molecules, such as volume-regulated anion channels, intracellular Ca2+ and cyclic nucleotide signaling, the Npas4 transcription factor and the FLRT family of axon guidance molecules. We also present an example illustrating that the same FLRT family may regulate the development of vascular networks as well. The aim of this review is to open up new vistas for understanding the intricacy of nervous and vascular system development.
Collapse
Affiliation(s)
- Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
| | - Tatsuro Kumada
- Department of Occupational Therapy, Faculty of Health and Medical Sciences, Tokoha University, 1230 Miyakoda-cho, Kita-ku, Hamamatsu, Shizuoka, 431-2102, Japan
| | - Sei-ichi Yoshihara
- Laboratory for Molecular Biology of Neural System, Advanced Medical Research Center, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | - Joaquim Egea
- Molecular and Developmental Neurobiology Group, Biomedical Research Institute of Lleida (IRBLleida), University of Lleida, 25198, Lleida, Spain
| | - Satoru Yamagishi
- Department of Anatomy and Neuroscience, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
| |
Collapse
|
37
|
Chen J, Kriegstein AR. A GABAergic projection from the zona incerta to cortex promotes cortical neuron development. Science 2015; 350:554-8. [PMID: 26429884 DOI: 10.1126/science.aac6472] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 09/10/2015] [Indexed: 12/30/2022]
Abstract
γ-Aminobutyric acid (GABA) is the major inhibitory transmitter in the mature brain but is excitatory in the developing cortex. We found that mouse zona incerta (ZI) projection neurons form a GABAergic axon plexus in neonatal cortical layer 1, making synapses with neurons in both deep and superficial layers. A similar depolarizing GABAergic plexus exists in the developing human cortex. Selectively silencing mouse ZI GABAergic neurons at birth decreased synaptic activity and apical dendritic complexity of cortical neurons. The ZI GABAergic projection becomes inhibitory with maturation and can block epileptiform activity in the adult brain. These data reveal an early-developing GABAergic projection from the ZI to cortical layer 1 that is essential for proper development of cortical neurons and balances excitation with inhibition in the adult cortex.
Collapse
Affiliation(s)
- Jiadong Chen
- Department of Neurology, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA 94143, USA.
| | - Arnold R Kriegstein
- Department of Neurology, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA 94143, USA.
| |
Collapse
|
38
|
Ovsepian SV, Vesselkin NP. Wiring prior to firing: the evolutionary rise of electrical and chemical modes of synaptic transmission. Rev Neurosci 2015; 25:821-32. [PMID: 25051277 DOI: 10.1515/revneuro-2014-0037] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 06/16/2014] [Indexed: 01/08/2023]
Abstract
Paracrine signaling and coupling via intercellular conduits are widely utilized for cell-cell interactions from primitive eukaryotes to advanced metazoa. Here, we review the functional and molecular data suggestive of a phylogenic continuum between these primeval forms of communication with the chemical and electrical synaptic transmission of neurons. We discuss selective evidence for the essential role played by the shift of function in early cellular morphologies and protosynaptic scaffolds, with their co-optation for new functionality, which ultimately lead to the rise of the chemical synapse. It is proposed that, rather than representing a transitional element, mixed electrochemical synapses exemplify an exaptive effect. The nonadaptive model of the synaptic origin described herein supports the pluralistic hypothesis of evolutionary change.
Collapse
|
39
|
Al-Jaberi N, Lindsay S, Sarma S, Bayatti N, Clowry GJ. The early fetal development of human neocortical GABAergic interneurons. Cereb Cortex 2015; 25:631-45. [PMID: 24047602 PMCID: PMC4318531 DOI: 10.1093/cercor/bht254] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
GABAergic interneurons are crucial to controlling the excitability and responsiveness of cortical circuitry. Their developmental origin may differ between rodents and human. We have demonstrated the expression of 12 GABAergic interneuron-associated genes in samples from human neocortex by quantitative rtPCR from 8 to 12 postconceptional weeks (PCW) and shown a significant anterior to posterior expression gradient, confirmed by in situ hybridization or immunohistochemistry for GAD1 and 2, DLX1, 2, and 5, ASCL1, OLIG2, and CALB2. Following cortical plate (CP) formation from 8 to 9 PCW, a proportion of cells were strongly stained for all these markers in the CP and presubplate. ASCL1 and DLX2 maintained high expression in the proliferative zones and showed extensive immunofluorescent double-labeling with the cell division marker Ki-67. CALB2-positive cells increased steadily in the SVZ/VZ from 10 PCW but were not double-labeled with Ki-67. Expression of GABAergic genes was generally higher in the dorsal pallium than in the ganglionic eminences, with lower expression in the intervening ventral pallium. It is widely accepted that the cortical proliferative zones may generate CALB2-positive interneurons from mid-gestation; we now show that the anterior neocortical proliferative layers especially may be a rich source of interneurons in the early neocortex.
Collapse
Affiliation(s)
- Nahidh Al-Jaberi
- Institute of Neuroscience Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Susan Lindsay
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Subrot Sarma
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Nadhim Bayatti
- Institute of Neuroscience Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK Current address: Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | | |
Collapse
|
40
|
Momose-Sato Y, Sato K, Kamino K. Monitoring Population Membrane Potential Signals During Development of the Vertebrate Nervous System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 859:213-42. [DOI: 10.1007/978-3-319-17641-3_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
|
41
|
Abstract
Gamma-amino butyric acid (GABA) is the major inhibitory neurotransmitter that is known to be synthesized and released from GABAergic neurons in the brain. However, recent studies have shown that not only neurons but also astrocytes contain a considerable amount of GABA that can be released and activate GABA receptors in neighboring neurons. These exciting new findings for glial GABA raise further interesting questions about the source of GABA, its mechanism of release and regulation and the functional role of glial GABA. In this review, we highlight recent studies that identify the presence and release of GABA in glial cells, we show several proposed potential pathways for accumulation and modulation of glial intracellular and extracellular GABA content, and finally we discuss functional roles for glial GABA in the brain.
Collapse
Affiliation(s)
- Bo-Eun Yoon
- Department of Nanobiomedical Science, Dankook University Chungnam, South Korea
| | - C Justin Lee
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST) Seoul, South Korea ; Center for Neural Science and Center for Functional Connectomics, Korea Institute of Science and Technology (KIST) Seoul, South Korea
| |
Collapse
|
42
|
Aimone JB, Li Y, Lee SW, Clemenson GD, Deng W, Gage FH. Regulation and function of adult neurogenesis: from genes to cognition. Physiol Rev 2014; 94:991-1026. [PMID: 25287858 DOI: 10.1152/physrev.00004.2014] [Citation(s) in RCA: 418] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Adult neurogenesis in the hippocampus is a notable process due not only to its uniqueness and potential impact on cognition but also to its localized vertical integration of different scales of neuroscience, ranging from molecular and cellular biology to behavior. This review summarizes the recent research regarding the process of adult neurogenesis from these different perspectives, with particular emphasis on the differentiation and development of new neurons, the regulation of the process by extrinsic and intrinsic factors, and their ultimate function in the hippocampus circuit. Arising from a local neural stem cell population, new neurons progress through several stages of maturation, ultimately integrating into the adult dentate gyrus network. The increased appreciation of the full neurogenesis process, from genes and cells to behavior and cognition, makes neurogenesis both a unique case study for how scales in neuroscience can link together and suggests neurogenesis as a potential target for therapeutic intervention for a number of disorders.
Collapse
Affiliation(s)
- James B Aimone
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Yan Li
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Star W Lee
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Gregory D Clemenson
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Wei Deng
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| | - Fred H Gage
- Cognitive Modeling Group, Sandia National Laboratories, Albuquerque, New Mexico; and Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, California
| |
Collapse
|
43
|
Kaila K, Price TJ, Payne JA, Puskarjov M, Voipio J. Cation-chloride cotransporters in neuronal development, plasticity and disease. Nat Rev Neurosci 2014; 15:637-54. [PMID: 25234263 DOI: 10.1038/nrn3819] [Citation(s) in RCA: 486] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Electrical activity in neurons requires a seamless functional coupling between plasmalemmal ion channels and ion transporters. Although ion channels have been studied intensively for several decades, research on ion transporters is in its infancy. In recent years, it has become evident that one family of ion transporters, cation-chloride cotransporters (CCCs), and in particular K(+)-Cl(-) cotransporter 2 (KCC2), have seminal roles in shaping GABAergic signalling and neuronal connectivity. Studying the functions of these transporters may lead to major paradigm shifts in our understanding of the mechanisms underlying brain development and plasticity in health and disease.
Collapse
Affiliation(s)
- Kai Kaila
- 1] Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland. [2] Neuroscience Center, University of Helsinki, 00014 Helsinki, Finland
| | - Theodore J Price
- University of Texas at Dallas, School of Behavior and Brain Sciences, Dallas, Texas 75093, USA
| | - John A Payne
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California 95616, USA
| | - Martin Puskarjov
- 1] Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland. [2] Neuroscience Center, University of Helsinki, 00014 Helsinki, Finland
| | - Juha Voipio
- Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
| |
Collapse
|
44
|
Glycine transporter-1 controls nonsynaptic inhibitory actions of glycine receptors in the neonatal rat hippocampus. J Neurosci 2014; 34:10003-9. [PMID: 25057202 DOI: 10.1523/jneurosci.0075-13.2014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although functional glycinergic synapses have not been identified in the hippocampus, neurons in this area express Cl(-) permeable extrasynaptic glycine receptors (GlyRs). In experiments on CA3 pyramidal neurons on postnatal day 0-6 rat hippocampal slices, we detected robust GlyR activity as a tonic current and as single-channel events. Glycine release was independent of neuronal activity or extracellular Ca(2+). The endogenous GlyR activity was strongly enhanced by inhibition of the glycine-transporter-1 (GlyT1). Blockade of GlyT1 also caused a profound increase in the baseline current induced by exogenous glycine. Inhibition of GlyT1 reduced the frequency of spontaneous network events known as field giant depolarizing potentials (fGDPs) and of the unit activity in the absence of synaptic transmission. This inhibitory action on fGDPs was mimicked by applying 2 μm glycine or 0.1 μm isoguvacine, a GABAA-receptor agonist. Furthermore, 2 μm glycine suppressed unit spiking in the absence of synaptic transmission. Hence, despite the well known depolarizing Cl(-) equilibrium potential of neonatal hippocampal neurons, physiologically relevant extracellular glycine concentrations can exert an inhibitory action. The present data show that, akin to GABA uptake, GlyT1 exerts a powerful modulatory action on network events in the newborn hippocampus.
Collapse
|
45
|
Andreae LC, Burrone J. The role of neuronal activity and transmitter release on synapse formation. Curr Opin Neurobiol 2014; 27:47-52. [PMID: 24632375 PMCID: PMC4127784 DOI: 10.1016/j.conb.2014.02.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 01/16/2014] [Accepted: 02/06/2014] [Indexed: 01/08/2023]
Abstract
The long history of probing the role of neuronal activity in the development of nervous system circuitry has recently taken an interesting turn. Although undoubtedly activity plays a critical part in the maintenance and refinement of synaptic connections, often via competitive mechanisms, evidence is building that it also drives the process of synapse formation itself. Perhaps predictably, this turns out not to be a uniform process. It seems that different circuits, indeed specific synaptic connections, are differentially sensitive to the effects of activity. We examine possible ways in which neurotransmitter may drive synapse formation, and speculate on how the environment of the developing brain may allow a different spatiotemporal range for neuronal activity to operate in the generation of connectivity.
Collapse
Affiliation(s)
- Laura C Andreae
- MRC Centre for Developmental Neurobiology, King's College London, New Hunt's House, 4th Floor, Guy's Hospital Campus, London SE1 1UL, UK.
| | - Juan Burrone
- MRC Centre for Developmental Neurobiology, King's College London, New Hunt's House, 4th Floor, Guy's Hospital Campus, London SE1 1UL, UK.
| |
Collapse
|
46
|
Acetylcholine controls GABA-, glutamate-, and glycine-dependent giant depolarizing potentials that govern spontaneous motoneuron activity at the onset of synaptogenesis in the mouse embryonic spinal cord. J Neurosci 2014; 34:6389-404. [PMID: 24790209 DOI: 10.1523/jneurosci.2664-13.2014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A remarkable feature of early neuronal networks is their endogenous ability to generate spontaneous rhythmic electrical activity independently of any external stimuli. In the mouse embryonic SC, this activity starts at an embryonic age of ∼ 12 d and is characterized by bursts of action potentials recurring every 2-3 min. Although these bursts have been extensively studied using extracellular recordings and are known to play an important role in motoneuron (MN) maturation, the mechanisms driving MN activity at the onset of synaptogenesis are still poorly understood. Because only cholinergic antagonists are known to abolish early spontaneous activity, it has long been assumed that spinal cord (SC) activity relies on a core network of MNs synchronized via direct cholinergic collaterals. Using a combination of whole-cell patch-clamp recordings and extracellular recordings in E12.5 isolated mouse SC preparations, we found that spontaneous MN activity is driven by recurrent giant depolarizing potentials. Our analysis reveals that these giant depolarizing potentials are mediated by the activation of GABA, glutamate, and glycine receptors. We did not detect direct nAChR activation evoked by ACh application on MNs, indicating that cholinergic inputs between MNs are not functional at this age. However, we obtained evidence that the cholinergic dependency of early SC activity reflects a presynaptic facilitation of GABA and glutamate synaptic release via nicotinic AChRs. Our study demonstrates that, even in its earliest form, the activity of spinal MNs relies on a refined poly-synaptic network and involves a tight presynaptic cholinergic regulation of both GABAergic and glutamatergic inputs.
Collapse
|
47
|
Wang T, Kumada T, Morishima T, Iwata S, Kaneko T, Yanagawa Y, Yoshida S, Fukuda A. Accumulation of GABAergic neurons, causing a focal ambient GABA gradient, and downregulation of KCC2 are induced during microgyrus formation in a mouse model of polymicrogyria. Cereb Cortex 2014; 24:1088-101. [PMID: 23246779 PMCID: PMC3948493 DOI: 10.1093/cercor/bhs375] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Although focal cortical malformations are considered neuronal migration disorders, their formation mechanisms remain unknown. We addressed how the γ-aminobutyric acid (GABA)ergic system affects the GABAergic and glutamatergic neuronal migration underlying such malformations. A focal freeze-lesion (FFL) of the postnatal day zero (P0) glutamic acid decarboxylase-green fluorescent protein knock-in mouse neocortex produced a 3- or 4-layered microgyrus at P7. GABAergic interneurons accumulated around the necrosis including the superficial region during microgyrus formation at P4, whereas E17.5-born, Cux1-positive pyramidal neurons outlined the GABAergic neurons and were absent from the superficial layer, forming cell-dense areas in layer 2 of the P7 microgyrus. GABA imaging showed that an extracellular GABA level temporally increased in the GABAergic neuron-positive area, including the necrotic center, at P4. The expression of the Cl(-) transporter KCC2 was downregulated in the microgyrus-forming GABAergic and E17.5-born glutamatergic neurons at P4; these cells may need a high intracellular Cl(-) concentration to induce depolarizing GABA effects. Bicuculline decreased the frequency of spontaneous Ca(2+) oscillations in these microgyrus-forming cells. Thus, neonatal FFL causes specific neuronal accumulation, preceded by an increase in ambient GABA during microgyrus formation. This GABA increase induces GABAA receptor-mediated Ca(2+) oscillation in KCC2-downregulated microgyrus-forming cells, as seen in migrating cells during early neocortical development.
Collapse
Affiliation(s)
- Tianying Wang
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Tatsuro Kumada
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Toshitaka Morishima
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Satomi Iwata
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Takeshi Kaneko
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan
- Japan Science and Technology Agency, CREST, Tokyo 102-0075, Japan and
| | - Sachiko Yoshida
- Department of Environmental and Life Sciences, Toyohashi University of Technology, Toyohashi, Aichi 441-8580, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| |
Collapse
|
48
|
Furukawa T, Yamada J, Akita T, Matsushima Y, Yanagawa Y, Fukuda A. Roles of taurine-mediated tonic GABAA receptor activation in the radial migration of neurons in the fetal mouse cerebral cortex. Front Cell Neurosci 2014; 8:88. [PMID: 24734001 PMCID: PMC3975117 DOI: 10.3389/fncel.2014.00088] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 03/10/2014] [Indexed: 11/15/2022] Open
Abstract
γ-Aminobutyric acid (GABA) depolarizes embryonic cerebrocortical neurons and continuous activation of the GABAA receptor (GABAAR) contributes to their tonic depolarization. Although multiple reports have demonstrated a role of GABAAR activation in neocortical development, including in migration, most of these studies have used pharmacological blockers. Herein, we performed in utero electroporation in GABA synthesis-lacking homozygous GAD67-GFP knock-in mice (GAD67GFP/GFP) to label neurons born in the ventricular zone. Three days after electroporation, there were no differences in the distribution of labeled cells between the genotypes. The dose–response properties of labeled cells to GABA were equivalent among genotypes. However, continuous blockade of GABAAR with the GABAAR antagonist SR95531 accelerated radial migration. This effect of GABAAR blockade in GAD67GFP/GFP mice suggested a role for alternative endogenous GABAAR agonists. Thus, we tested the role of taurine, which is derived from maternal blood but is abundant in the fetal brain. The taurine-evoked currents in labeled cells were mediated by GABAAR. Taurine uptake was blocked by a taurine transporter inhibitor, 2-(guanidino)ethanesulfonic acid (GES), and taurine release was blocked by a volume-sensitive anion channel blocker, 4-(2-butyl-6,7-dichlor-2-cyclopentylindan-1-on-5-yl) oxobutyric acid, as examined through high-performance liquid chromatography. GES increased the extracellular taurine concentration and induced an inward shift of the holding current, which was reversed by SR95531. In a taurine-deficient mouse model, the GABAAR-mediated tonic currents were greatly reduced, and radial migration was accelerated. As the tonic currents were equivalent among the genotypes of GAD67-GFP knock-in mice, taurine, rather than GABA, might play a major role as an endogenous agonist of embryonic tonic GABAAR conductance, regulating the radial migration of neurons in the developing neocortex.
Collapse
Affiliation(s)
- Tomonori Furukawa
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Junko Yamada
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan ; Department of Neurophysiology, Hirosaki University Graduate School of Medicine Hirosaki, Aomori, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Yoshitaka Matsushima
- Department of Chemistry, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine Maebashi, Gunma, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| |
Collapse
|
49
|
Luhmann HJ, Kirischuk S, Sinning A, Kilb W. Early GABAergic circuitry in the cerebral cortex. Curr Opin Neurobiol 2014; 26:72-8. [PMID: 24434608 DOI: 10.1016/j.conb.2013.12.014] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 11/25/2013] [Accepted: 12/19/2013] [Indexed: 10/25/2022]
Abstract
In the cerebral cortex GABAergic signaling plays an important role in regulating early developmental processes, for example, neurogenesis, migration and differentiation. Transient cell populations, namely Cajal-Retzius in the marginal zone and thalamic input receiving subplate neurons, are integrated as active elements in transitory GABAergic circuits. Although immature pyramidal neurons receive GABAergic synaptic inputs already at fetal stages, they are integrated into functional GABAergic circuits only several days later. In consequence, GABAergic synaptic transmission has only a minor influence on spontaneous network activity during early corticogenesis. Concurrent with the gradual developmental shift of GABA action from excitatory to inhibitory and the maturation of cortical synaptic connections, GABA becomes more important in synchronizing neuronal network activity.
Collapse
Affiliation(s)
- Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany.
| | - Sergei Kirischuk
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany
| | - Anne Sinning
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany
| |
Collapse
|
50
|
Cellot G, Cherubini E. GABAergic signaling as therapeutic target for autism spectrum disorders. Front Pediatr 2014; 2:70. [PMID: 25072038 PMCID: PMC4085902 DOI: 10.3389/fped.2014.00070] [Citation(s) in RCA: 176] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 06/23/2014] [Indexed: 11/13/2022] Open
Abstract
γ-Aminobutyric acid (GABA), the main inhibitory neurotransmitter in the adult brain, early in postnatal life exerts a depolarizing and excitatory action. This depends on accumulation of chloride inside the cell via the cation-chloride importer NKCC1, being the expression of the chloride exporter KCC2 very low at birth. The developmentally regulated expression of KCC2 results in extrusion of chloride with age and a shift of GABA from the depolarizing to the hyperpolarizing direction. The depolarizing action of GABA leads to intracellular calcium rise through voltage-dependent calcium channels and/or N-methyl-d-aspartate receptors. GABA-mediated calcium signals regulate a variety of developmental processes from cell proliferation migration, differentiation, synapse maturation, and neuronal wiring. Therefore, it is not surprising that some forms of neuro-developmental disorders such as autism spectrum disorders (ASDs) are associated with alterations of GABAergic signaling and impairment of the excitatory/inhibitory balance in selective neuronal circuits. In this review, we will discuss how changes of GABAA-mediated neurotransmission affect several forms of ASDs including the Fragile X, the Angelman, and Rett syndromes. Then, we will describe various animal models of ASDs with GABAergic dysfunctions, highlighting their behavioral deficits and the possibility to rescue them by targeting selective components of the GABAergic synapse. In particular, we will discuss how in some cases, reverting the polarity of GABA responses from the depolarizing to the hyperpolarizing direction with the diuretic bumetanide, a selective blocker of NKCC1, may have beneficial effects on ASDs, thus opening new therapeutic perspectives for the treatment of these devastating disorders.
Collapse
Affiliation(s)
- Giada Cellot
- Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati , Trieste , Italy
| | - Enrico Cherubini
- Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati , Trieste , Italy ; European Brain Research Institute , Rome , Italy
| |
Collapse
|