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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.
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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
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2
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Ultrasensitive and Simple Dopamine Electrochemical Sensor Based on the Synergistic Effect of Cu-TCPP Frameworks and Graphene Nanosheets. Molecules 2023; 28:molecules28062687. [PMID: 36985659 PMCID: PMC10051941 DOI: 10.3390/molecules28062687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 03/19/2023] Open
Abstract
Dopamine (DA) is an important neurotransmitter. Abnormal concentration of DA can result in many neurological diseases. Developing reliable determination methods for DA is of great significance for the diagnosis and monitoring of neurological diseases. Here, a novel and simple electrochemical sensing platform for quantitative analysis of DA was constructed based on the Cu-TCPP/graphene composite (TCPP: Tetrakis(4-carboxyphenyl)porphyrin). Cu-TCPP frameworks were selected in consideration of their good electrochemical sensing potential. The graphene nanosheets with excellent conductivity were then added to further improve the sensing efficiency and stability of Cu-TCPP frameworks. The electrochemical properties of the Cu-TCPP/graphene composite were characterized, showing its large electrode active area, fast electron transfer, and good sensing performance toward DA. The signal enhancement mechanism of DA was explored. Strong accumulation ability and high electrocatalytic rate were observed on the surface of Cu-TCPP/graphene-modified glassy carbon electrode (Cu-TCPP/graphene/GCE). Based on the synergistic sensitization effect, an ultrasensitive and simple DA electrochemical sensor was developed. The linear range is 0.02–100 and 100–1000 µM, and the detection limit is 3.6 nM for the first linear range. It was also successfully used in detecting DA in serum samples, and a satisfactory recovery was obtained.
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3
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Salceda R. Glycine neurotransmission: Its role in development. Front Neurosci 2022; 16:947563. [PMID: 36188468 PMCID: PMC9525178 DOI: 10.3389/fnins.2022.947563] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/30/2022] [Indexed: 11/13/2022] Open
Abstract
The accurate function of the central nervous system (CNS) depends of the consonance of multiple genetic programs and external signals during the ontogenesis. A variety of molecules including neurotransmitters, have been implied in the regulation of proliferation, survival, and cell-fate of neurons and glial cells. Among these, neurotransmitters may play a central role since functional ligand-gated ionic channel receptors have been described before the establishment of synapses. This review argues on the function of glycine during development, and show evidence indicating it regulates morphogenetic events by means of their transporters and receptors, emphasizing the role of glycinergic activity in the balance of excitatory and inhibitory signals during development. Understanding the mechanisms involved in these processes would help us to know the etiology of cognitive dysfunctions and lead to improve brain repair strategies.
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4
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Locomotion dependent neuron-glia interactions control neurogenesis and regeneration in the adult zebrafish spinal cord. Nat Commun 2021; 12:4857. [PMID: 34381039 PMCID: PMC8357999 DOI: 10.1038/s41467-021-25052-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 07/21/2021] [Indexed: 01/09/2023] Open
Abstract
Physical exercise stimulates adult neurogenesis, yet the underlying mechanisms remain poorly understood. A fundamental component of the innate neuroregenerative capacity of zebrafish is the proliferative and neurogenic ability of the neural stem/progenitor cells. Here, we show that in the intact spinal cord, this plasticity response can be activated by physical exercise by demonstrating that the cholinergic neurotransmission from spinal locomotor neurons activates spinal neural stem/progenitor cells, leading to neurogenesis in the adult zebrafish. We also show that GABA acts in a non-synaptic fashion to maintain neural stem/progenitor cell quiescence in the spinal cord and that training-induced activation of neurogenesis requires a reduction of GABAA receptors. Furthermore, both pharmacological stimulation of cholinergic receptors, as well as interference with GABAergic signaling, promote functional recovery after spinal cord injury. Our findings provide a model for locomotor networks’ activity-dependent neurogenesis during homeostasis and regeneration in the adult zebrafish spinal cord. The mechanisms stimulating adult neurogenesis are unclear. Here, the authors show the contribution of cholinergic and GABAergic signalling within the locomotor network to spinal cord neurogenesis during homeostasis and regeneration, showing neurogenesis depends on circuit activity in the adult zebrafish.
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Sokpor G, Kerimoglu C, Nguyen H, Pham L, Rosenbusch J, Wagener R, Nguyen HP, Fischer A, Staiger JF, Tuoc T. Loss of BAF Complex in Developing Cortex Perturbs Radial Neuronal Migration in a WNT Signaling-Dependent Manner. Front Mol Neurosci 2021; 14:687581. [PMID: 34220450 PMCID: PMC8243374 DOI: 10.3389/fnmol.2021.687581] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/20/2021] [Indexed: 12/22/2022] Open
Abstract
Radial neuronal migration is a key neurodevelopmental event indispensable for proper cortical laminar organization. Cortical neurons mainly use glial fiber guides, cell adhesion dynamics, and cytoskeletal remodeling, among other discrete processes, to radially trek from their birthplace to final layer positions. Dysregulated radial migration can engender cortical mis-lamination, leading to neurodevelopmental disorders. Epigenetic factors, including chromatin remodelers have emerged as formidable regulators of corticogenesis. Notably, the chromatin remodeler BAF complex has been shown to regulate several aspects of cortical histogenesis. Nonetheless, our understanding of how BAF complex regulates neuronal migration is limited. Here, we report that BAF complex is required for neuron migration during cortical development. Ablation of BAF complex in the developing mouse cortex caused alteration in the cortical gene expression program, leading to loss of radial migration-related factors critical for proper cortical layer formation. Of note, BAF complex inactivation in cortex caused defective neuronal polarization resulting in diminished multipolar-to-bipolar transition and eventual disruption of radial migration of cortical neurons. The abnormal radial migration and cortical mis-lamination can be partly rescued by downregulating WNT signaling hyperactivity in the BAF complex mutant cortex. By implication, the BAF complex modulates WNT signaling to establish the gene expression program required for glial fiber-dependent neuronal migration, and cortical lamination. Overall, BAF complex has been identified to be crucial for cortical morphogenesis through instructing multiple aspects of radial neuronal migration in a WNT signaling-dependent manner.
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Affiliation(s)
- Godwin Sokpor
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany.,Department of Human Genetics, Ruhr University of Bochum, Bochum, Germany
| | - Cemil Kerimoglu
- German Center for Neurodegenerative Diseases, Göttingen, Germany
| | - Huong Nguyen
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany.,Faculty of Biotechnology, Thai Nguyen University of Sciences, Thai Nguyen, Vietnam
| | - Linh Pham
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany.,Department of Human Genetics, Ruhr University of Bochum, Bochum, Germany
| | - Joachim Rosenbusch
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany
| | - Robin Wagener
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany.,Department of Neurology, University Medical Center Heidelberg, Heidelberg, Germany.,Neurooncology Clinical Cooperation Unit, German Cancer Research Center, Heidelberg, Germany
| | - Huu Phuc Nguyen
- Department of Human Genetics, Ruhr University of Bochum, Bochum, Germany
| | - Andre Fischer
- German Center for Neurodegenerative Diseases, Göttingen, Germany.,Department for Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Jochen F Staiger
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany
| | - Tran Tuoc
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany.,Department of Human Genetics, Ruhr University of Bochum, Bochum, Germany
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Anancia Grace A, Divya KP, Dharuman V, Hahn JH. Single step sol-gel synthesized Mn2O3-TiO2 decorated graphene for the rapid and selective ultra sensitive electrochemical sensing of dopamine. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.02.053] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Zafar S, Jabeen I. GRID-independent molecular descriptor analysis and molecular docking studies to mimic the binding hypothesis of γ-aminobutyric acid transporter 1 (GAT1) inhibitors. PeerJ 2019; 7:e6283. [PMID: 30723616 PMCID: PMC6360079 DOI: 10.7717/peerj.6283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 12/14/2018] [Indexed: 12/13/2022] Open
Abstract
Background The γ-aminobutyric acid (GABA) transporter GAT1 is involved in GABA transport across the biological membrane in and out of the synaptic cleft. The efficiency of this Na+ coupled GABA transport is regulated by an electrochemical gradient, which is directed inward under normal conditions. However, in certain pathophysiological situations, including strong depolarization or an imbalance in ion homeostasis, the GABA influx into the cytoplasm is increased by re-uptake transport mechanism. This mechanism may lead to extra removal of extracellular GABA which results in numerous neurological disorders such as epilepsy. Thus, small molecule inhibitors of GABA re-uptake may enhance GABA activity at the synaptic clefts. Methods In the present study, various GRID-independent molecular descriptor (GRIND) models have been developed to shed light on the 3D structural features of human GAT1 (hGAT1) inhibitors using nipecotic acid and N-diarylalkenyl piperidine analogs. Further, a binding hypothesis has been developed for the selected GAT1 antagonists by molecular docking inside the binding cavity of hGAT1 homology model. Results Our results indicate that two hydrogen bond acceptors, one hydrogen bond donor and one hydrophobic region at certain distances from each other play an important role in achieving high inhibitory potency against hGAT1. Our docking results elucidate the importance of the COOH group in hGAT1 antagonists by considering substitution of the COOH group with an isoxazol ring in compound 37, which subsequently leads to a three order of magnitude decrease in biological activity of 37 (IC50 = 38 µM) as compared to compound 1 (IC50 = 0.040 µM). Discussion Our docking results are strengthened by the structure activity relationship of the data series as well as by GRIND models, thus providing a significant structural basis for understanding the binding of antagonists, which may be useful for guiding the design of hGAT1 inhibitors.
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Affiliation(s)
- Sadia Zafar
- Research Center for Modeling and Simulation (RCMS), National University of Sciences and Technology (NUST), Islamabad, Federal, Pakistan
| | - Ishrat Jabeen
- Research Center for Modeling and Simulation (RCMS), National University of Sciences and Technology (NUST), Islamabad, Federal, Pakistan
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8
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Wang T, Sinha AS, Akita T, Yanagawa Y, Fukuda A. Alterations of GABAergic Neuron-Associated Extracellular Matrix and Synaptic Responses in Gad1-Heterozygous Mice Subjected to Prenatal Stress. Front Cell Neurosci 2018; 12:284. [PMID: 30233323 PMCID: PMC6133952 DOI: 10.3389/fncel.2018.00284] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 08/10/2018] [Indexed: 12/29/2022] Open
Abstract
Exposure to prenatal stress (PS) and mutations in Gad1, which encodes GABA synthesizing enzyme glutamate decarboxylase (GAD) 67, are the primary risk factors for psychiatric disorders associated with abnormalities in parvalbumin (PV)-positive GABAergic interneurons in the medial prefrontal cortex (mPFC). Decreased expression of extracellular matrix (ECM) glycoproteins has also been reported in patients with these disorders, raising the possibility that ECM abnormalities may play a role in their pathogenesis. To elucidate pathophysiological changes in ECM induced by the gene–environment interaction, we examined heterozygous GAD67-GFP (Knock-In KI; GAD67+/GFP) mice subjected to PS from embryonic day 15.0 to 17.5. Consistent with our previous study, we confirmed a decrease in the density of PV neurons in the mPFC of postnatal GAD67+/GFP mice with PS, which was concurrent with a decrease in density of PV neurons surrounded by perineuronal nets (PNNs), a specialized ECM important for the maturation, synaptic stabilization and plasticity of PV neurons. Glycosylation of α-dystroglycan (α-DG) and its putative mediator fukutin (Fktn) in the ECM around inhibitory synapses has also been suggested to contribute to disease development. We found that both glycosylated α-DG and the mRNA level of Fktn were reduced in GAD67+/GFP mice with PS. None of these changes were detected in GAD67+/GFP naive mice or wild type (GAD67+/+) mice with PS, suggesting that both PS and reduced Gad1 gene expression are prerequisites for these changes. When assessing the function of interneurons in the mPFC of GAD67+/GFP mice with PS through evoked inhibitory post-synaptic currents (eIPSCs) in layer V pyramidal neurons, we found that the threshold stimulus intensity for eIPSC events was reduced and that the eIPSC amplitude was increased without changes in the paired-pulse ratio (PPR). Moreover, the decay rate of eIPSCs was also slowed. In line with eIPSC, spontaneous IPSC (sIPSC) amplitude, frequency and decay tau were altered. Thus, our study suggests that alterations in the ECM mediated by gene-environment interactions might be linked to the enhanced and prolonged GABA action that compensates for the decreased density of PV neurons. This might be one of the causes of the excitatory/inhibitory imbalance in the mPFC of psychiatric patients.
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Affiliation(s)
- Tianying Wang
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Adya Saran Sinha
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Graduate School of Medicine, Gunma University, Maebashi, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Japan.,Advanced Research Facilities and Services, Preeminent Medical Photonics Education and Research Center, Department of Genetic and Behavioral Neuroscience, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Dark C, Homman-Ludiye J, Bryson-Richardson RJ. The role of ADHD associated genes in neurodevelopment. Dev Biol 2018; 438:69-83. [DOI: 10.1016/j.ydbio.2018.03.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 03/04/2018] [Accepted: 03/27/2018] [Indexed: 12/19/2022]
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Hurni N, Kolodziejczak M, Tomasello U, Badia J, Jacobshagen M, Prados J, Dayer A. Transient Cell-intrinsic Activity Regulates the Migration and Laminar Positioning of Cortical Projection Neurons. Cereb Cortex 2018; 27:3052-3063. [PMID: 28334356 DOI: 10.1093/cercor/bhx059] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 02/23/2017] [Indexed: 12/21/2022] Open
Abstract
Neocortical microcircuits are built during development and require the coordinated assembly of excitatory glutamatergic projection neurons (PNs) into functional networks. Neuronal migration is an essential step in this process. In addition to cell-intrinsic mechanisms, external cues including neurotransmitters regulate cortical neuron migration, suggesting that early activity could influence this process. Here, we aimed to investigate the role of cell-intrinsic activity in migrating PNs in vivo using a designer receptor exclusively activated by a designer drug (DREADD) chemogenetic approach. In utero electroporation was used to specifically express the human M3 muscarinic cholinergic Gq-coupled receptor (hM3Dq) in PNs and calcium activity, migratory dynamics, gene expression, and laminar positioning of PNs were assessed following embryonic DREADD activation. We found that transient embryonic DREADD activation induced premature branching and transcriptional changes in migrating PNs leading to a persistent laminar mispositioning of superficial layer PNs into deep cortical layers without affecting expression of layer-specific molecular identity markers. In addition, live imaging approaches indicated that embryonic DREADD activation increased calcium transients in migrating PNs and altered their migratory dynamics by increasing their pausing time. Taken together, these results support the idea that increased cell-intrinsic activity during migration acts as a stop signal for migrating cortical PNs.
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Affiliation(s)
- Nicolas Hurni
- Department of Psychiatry, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland.,Department of Basic Neurosciences, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland
| | - Marta Kolodziejczak
- Department of Psychiatry, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland.,Department of Basic Neurosciences, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland
| | - Ugo Tomasello
- Department of Psychiatry, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland.,Department of Basic Neurosciences, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland
| | - Joan Badia
- Department of Psychiatry, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland.,Department of Basic Neurosciences, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland
| | - Moritz Jacobshagen
- Department of Psychiatry, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland.,Department of Basic Neurosciences, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland
| | - Julien Prados
- Department of Psychiatry, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland.,Department of Basic Neurosciences, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland
| | - Alexandre Dayer
- Department of Psychiatry, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland.,Department of Basic Neurosciences, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland
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11
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EARLY gestational exposure to isoflurane causes persistent cell loss in the dentate gyrus of adult male rats. Behav Brain Funct 2017; 13:14. [PMID: 29279051 PMCID: PMC5744391 DOI: 10.1186/s12993-017-0132-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 12/20/2017] [Indexed: 11/23/2022] Open
Abstract
Background Our previous research showed that 4 h of maternal anesthesia with isoflurane during early gestation in pregnant rats leads to a deficit in spatial memory of adult male offspring. Because spatial memory is predominantly a hippocampally-mediated task, we asked the question if early gestational exposure to isoflurane affects development of the hippocampus in the offspring. Findings Previously behaviorally characterized adult male rats that were exposed to isoflurane during second trimester were sacrificed at 4 months of age (N = 10 and 13, control and isoflurane groups, respectively) for quantitative histology of hippocampal subregions. Sections were stained with cresyl violet and the total number of cells in the granular layer of the dentate gyrus and the pyramidal cell layer in the CA1 region were determined by a blinded observer using unbiased stereological principles and the optical fractionator method. Data were analyzed using Student’s t test; P < 0.05 was accorded statistical significance. Stereological examination revealed 9% fewer cells in the granular layer of the dentate gyrus of isoflurane-exposed adult rats compared to controls (1,002,122 ± 84,870 vs. 1,091,829 ± 65,791, respectively; Mean ± S.D, *P = 0.01). In contrast, there were no changes in the cell number in the CA1 region, nor were there changes in the volumes of both regions. Conclusions Our results show that maternal isoflurane anesthesia in rodents causes region-specific cell loss in the hippocampus of adult male offspring. These changes may, in part, account for the behavioral deficits reported in adult rats exposed to isoflurane in utero.
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12
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Potential Role of Microtubule Stabilizing Agents in Neurodevelopmental Disorders. Int J Mol Sci 2017; 18:ijms18081627. [PMID: 28933765 PMCID: PMC5578018 DOI: 10.3390/ijms18081627] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/10/2017] [Accepted: 07/18/2017] [Indexed: 01/05/2023] Open
Abstract
Neurodevelopmental disorders (NDDs) are characterized by neuroanatomical abnormalities indicative of corticogenesis disturbances. At the basis of NDDs cortical abnormalities, the principal developmental processes involved are cellular proliferation, migration and differentiation. NDDs are also considered “synaptic disorders” since accumulating evidence suggests that NDDs are developmental brain misconnection syndromes characterized by altered connectivity in local circuits and between brain regions. Microtubules and microtubule-associated proteins play a fundamental role in the regulation of basic neurodevelopmental processes, such as neuronal polarization and migration, neuronal branching and synaptogenesis. Here, the role of microtubule dynamics will be elucidated in regulating several neurodevelopmental steps. Furthermore, the correlation between abnormalities in microtubule dynamics and some NDDs will be described. Finally, we will discuss the potential use of microtubule stabilizing agents as a new pharmacological intervention for NDDs treatment.
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13
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Morelli G, Avila A, Ravanidis S, Aourz N, Neve RL, Smolders I, Harvey RJ, Rigo JM, Nguyen L, Brône B. Cerebral Cortical Circuitry Formation Requires Functional Glycine Receptors. Cereb Cortex 2017; 27:1863-1877. [PMID: 26891984 DOI: 10.1093/cercor/bhw025] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The development of the cerebral cortex is a complex process that requires the generation, migration, and differentiation of neurons. Interfering with any of these steps can impair the establishment of connectivity and, hence, function of the adult brain. Neurotransmitter receptors have emerged as critical players to regulate these biological steps during brain maturation. Among them, α2 subunit-containing glycine receptors (GlyRs) regulate cortical neurogenesis and the present work demonstrates the long-term consequences of their genetic disruption on neuronal connectivity in the postnatal cerebral cortex. Our data indicate that somatosensory cortical neurons of Glra2 knockout mice (Glra2KO) have more dendritic branches with an overall increase in total spine number. These morphological defects correlate with a disruption of the excitation/inhibition balance, thereby increasing network excitability and enhancing susceptibility to epileptic seizures after pentylenetetrazol tail infusion. Taken together, our findings show that the loss of embryonic GlyRα2 ultimately impairs the formation of cortical circuits in the mature brain.
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Affiliation(s)
- Giovanni Morelli
- BIOMED Research Institute, Hasselt University, Hasselt 3500, Belgium.,GIGA-Neurosciences.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R)
| | - Ariel Avila
- Program in Neurosciences and Mental Health, SickKids Research Institute, The Hospital for Sick Children (SickKids), Toronto, ON, CanadaM5G 1X8
| | | | - Najat Aourz
- Department of Pharmaceutical Chemistry and Drug Analysis, C4N, Center for Neuroscience, Vrije Universiteit Brussel, 1090 Brussel, Belgium
| | - Rachael L Neve
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry and Drug Analysis, C4N, Center for Neuroscience, Vrije Universiteit Brussel, 1090 Brussel, Belgium
| | - Robert J Harvey
- Department of Pharmacology, UCL School of Pharmacy, London WC1N 1AX, UK
| | - Jean-Michel Rigo
- BIOMED Research Institute, Hasselt University, Hasselt 3500, Belgium
| | - Laurent Nguyen
- GIGA-Neurosciences.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R).,Walloon Excellence in Lifesciences and Biotechnology (WELBIO), University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium
| | - Bert Brône
- BIOMED Research Institute, Hasselt University, Hasselt 3500, Belgium
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Tallafuss A, Kelly M, Gay L, Gibson D, Batzel P, Karfilis KV, Eisen J, Stankunas K, Postlethwait JH, Washbourne P. Transcriptomes of post-mitotic neurons identify the usage of alternative pathways during adult and embryonic neuronal differentiation. BMC Genomics 2015; 16:1100. [PMID: 26699284 PMCID: PMC4690400 DOI: 10.1186/s12864-015-2215-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 11/16/2015] [Indexed: 05/14/2023] Open
Abstract
Background Understanding the mechanisms by which neurons are generated and specified, and how they integrate into functional circuits is key to being able to treat disorders of the nervous system and acute brain trauma. Much of what we know about neuronal differentiation has been studied in developing embryos, but differentiation steps may be very different during adult neurogenesis. For this reason, we compared the transcriptomes of newly differentiated neurons in zebrafish embryos and adults. Results Using a 4tU RNA labeling method, we isolated and sequenced mRNA specifically from cells of one day old embryos and adults expressing the transgene HA-uprt-mcherry under control of the neuronal marker elavl3. By categorizing transcript products into different protein classes, we identified similarities and differences of gene usage between adult and embryonic neuronal differentiation. We found that neurons in the adult brain and in the nervous system of one day old embryos commonly use transcription factors - some of them identical - during the differentiation process. When we directly compared adult differentiating neurons to embryonic differentiating neurons, however, we found that during adult neuronal differentiation, the expression of neuropeptides and neurotransmitter pathway genes is more common, whereas classical developmental signaling through secreted molecules like Hedgehog or Wnt are less enriched, as compared to embryonic stages. Conclusions We conclude that both adult and embryonic differentiating neurons show enriched use of transcription factors compared to surrounding cells. However, adult and embryonic developing neurons use alternative pathways to differentiate. Our study provides evidence that adult neuronal differentiation is distinct from the better characterized embryonic neuronal differentiation process. This important insight and the lists of enriched genes we have identified will now help pave the way to a better understanding of the mechanisms of embryonic and adult neuronal differentiation and how to manipulate these processes. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2215-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Meghan Kelly
- Institute of Neuroscience, University of Oregon, Eugene, OR, USA.
| | - Leslie Gay
- Institute of Molecular Biology, University of Oregon, Eugene, OR, USA.
| | - Dan Gibson
- Current address: Vollum Institute, Oregon Health and Science University, Portland, OR, USA.
| | - Peter Batzel
- Institute of Neuroscience, University of Oregon, Eugene, OR, USA.
| | - Kate V Karfilis
- Institute of Molecular Biology, University of Oregon, Eugene, OR, USA.
| | - Judith Eisen
- Institute of Neuroscience, University of Oregon, Eugene, OR, USA.
| | - Kryn Stankunas
- Institute of Molecular Biology, University of Oregon, Eugene, OR, USA.
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15
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Özel RE, Hayat A, Andreescu S. RECENT DEVELOPMENTS IN ELECTROCHEMICAL SENSORS FOR THE DETECTION OF NEUROTRANSMITTERS FOR APPLICATIONS IN BIOMEDICINE. ANAL LETT 2015; 48:1044-1069. [PMID: 26973348 PMCID: PMC4787221 DOI: 10.1080/00032719.2014.976867] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neurotransmitters are important biological molecules that are essential to many neurophysiological processes including memory, cognition, and behavioral states. The development of analytical methodologies to accurately detect neurotransmitters is of great importance in neurological and biological research. Specifically designed microelectrodes or microbiosensors have demonstrated potential for rapid, real-time measurements with high spatial resolution. Such devices can facilitate study of the role and mechanism of action of neurotransmitters and can find potential uses in biomedicine. This paper reviews the current status and recent advances in the development and application of electrochemical sensors for the detection of small-molecule neurotransmitters. Measurement challenges and opportunities of electroanalytical methods to advance study and understanding of neurotransmitters in various biological models and disease conditions are discussed.
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Affiliation(s)
- Rıfat Emrah Özel
- Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, NY, USA. Fax: 3152686610; Tel: 3152682394
| | - Akhtar Hayat
- Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, NY, USA. Fax: 3152686610; Tel: 3152682394
- Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS Institute of Information Technology (CIIT), Lahore, Pakistan
| | - Silvana Andreescu
- Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, NY, USA. Fax: 3152686610; Tel: 3152682394
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16
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Peyre E, Silva CG, Nguyen L. Crosstalk between intracellular and extracellular signals regulating interneuron production, migration and integration into the cortex. Front Cell Neurosci 2015; 9:129. [PMID: 25926769 PMCID: PMC4396449 DOI: 10.3389/fncel.2015.00129] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/19/2015] [Indexed: 11/29/2022] Open
Abstract
During embryogenesis, cortical interneurons are generated by ventral progenitors located in the ganglionic eminences of the telencephalon. They travel along multiple tangential paths to populate the cortical wall. As they reach this structure they undergo intracortical dispersion to settle in their final destination. At the cellular level, migrating interneurons are highly polarized cells that extend and retract processes using dynamic remodeling of microtubule and actin cytoskeleton. Different levels of molecular regulation contribute to interneuron migration. These include: (1) Extrinsic guidance cues distributed along migratory streams that are sensed and integrated by migrating interneurons; (2) Intrinsic genetic programs driven by specific transcription factors that grant specification and set the timing of migration for different subtypes of interneurons; (3) Adhesion molecules and cytoskeletal elements/regulators that transduce molecular signalings into coherent movement. These levels of molecular regulation must be properly integrated by interneurons to allow their migration in the cortex. The aim of this review is to summarize our current knowledge of the interplay between microenvironmental signals and cell autonomous programs that drive cortical interneuron porduction, tangential migration, and intergration in the developing cerebral cortex.
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Affiliation(s)
- Elise Peyre
- GIGA-Neurosciences, University of Liège Liège, Belgium ; Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège Liège, Belgium
| | - Carla G Silva
- GIGA-Neurosciences, University of Liège Liège, Belgium ; Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège Liège, Belgium
| | - Laurent Nguyen
- GIGA-Neurosciences, University of Liège Liège, Belgium ; Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège Liège, Belgium ; Wallon Excellence in Lifesciences and Biotechnology, University of Liège Liège, Belgium
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17
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Jacobshagen M, Niquille M, Chaumont-Dubel S, Marin P, Dayer A. The serotonin 6 receptor controls neuronal migration during corticogenesis via a ligand-independent Cdk5-dependent mechanism. Development 2014; 141:3370-7. [PMID: 25078650 PMCID: PMC4199128 DOI: 10.1242/dev.108043] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The formation of a laminar structure such as the mammalian neocortex relies on the coordinated migration of different subtypes of excitatory pyramidal neurons in specific layers. Cyclin-dependent kinase 5 (Cdk5) is a master regulator of pyramidal neuron migration. Recently, we have shown that Cdk5 binds to the serotonin 6 receptor (5-HT6R), a G protein-coupled receptor (GPCR). Here, we investigated the role of 5-HT6R in the positioning and migration of pyramidal neurons during mouse corticogenesis. We report that constitutive expression of 5-HT6R controls pyramidal neuron migration through an agonist-independent mechanism that requires Cdk5 activity. These data provide the first in vivo evidence of a role for constitutive activity at a GPCR in neocortical radial migration.
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Affiliation(s)
- Moritz Jacobshagen
- Department of Psychiatry, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland Department of Basic Neurosciences, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland
| | - Mathieu Niquille
- Department of Psychiatry, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland Department of Basic Neurosciences, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland
| | - Séverine Chaumont-Dubel
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, INSERM U661, Universités Montpellier I & II, Montpellier 34094, France
| | - Philippe Marin
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, INSERM U661, Universités Montpellier I & II, Montpellier 34094, France
| | - Alexandre Dayer
- Department of Psychiatry, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland Department of Basic Neurosciences, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland
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18
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Glycine receptors control the generation of projection neurons in the developing cerebral cortex. Cell Death Differ 2014; 21:1696-708. [PMID: 24926615 DOI: 10.1038/cdd.2014.75] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/10/2014] [Accepted: 04/29/2014] [Indexed: 01/13/2023] Open
Abstract
The development of the cerebral cortex requires coordinated regulation of proliferation, specification, migration and differentiation of cortical progenitors into functionally integrated neurons. The completion of the neurogenic program requires a dynamic interplay between cell intrinsic regulators and extrinsic cues, such as growth factor and neurotransmitters. We previously demonstrated a role for extrasynaptic glycine receptors (GlyRs) containing the α2 subunit in cerebral cortical neurogenesis, revealing that endogenous GlyR activation promotes interneuron migration in the developing cortical wall. The proliferative compartment of the cortex comprises apical progenitors that give birth to neurons directly or indirectly through the generation of basal progenitors, which serve as amplification step to generate the bulk of cortical neurons. The present work shows that genetic inactivation of Glra2, the gene coding the α2 subunit of GlyRs, disrupts dorsal cortical progenitor homeostasis with an impaired capability of apical progenitors to generate basal progenitors. This defect results in an overall reduction of projection neurons that settle in upper or deep layers of the cerebral cortex. Overall, the depletion of cortical neurons observed in Glra2-knockout embryos leads to moderate microcephaly in newborn Glra2-knockout mice. Taken together, our findings support a contribution of GlyR α2 to early processes in cerebral cortical neurogenesis that are required later for the proper development of cortical circuits.
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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.
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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
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20
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Abstract
Proper lamination of the cerebral cortex is precisely orchestrated, especially when neurons migrate from their place of birth to their final destination. The consequences of failure or delay in neuronal migration cause a wide range of disorders, such as lissencephaly, schizophrenia, autism and mental retardation. Neuronal migration is a dynamic process, which requires dynamic remodeling of the cytoskeleton. In this context microtubules and microtubule-related proteins have been suggested to play important roles in the regulation of neuronal migration. Here, we will review the dynamic aspects of neuronal migration and brain development, describe the molecular and cellular mechanisms of neuronal migration and elaborate on neuronal migration diseases.
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21
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Novel functions of core cell cycle regulators in neuronal migration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 800:59-74. [PMID: 24243100 DOI: 10.1007/978-94-007-7687-6_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cerebral cortex is one of the most intricate regions of the brain, which required elaborated cell migration patterns for its development. Experimental observations show that projection neurons migrate radially within the cortical wall, whereas interneurons migrate along multiple tangential paths to reach the developing cortex. Tight regulation of the cell migration processes ensures proper positioning and functional integration of neurons to specific cerebral cortical circuits. Disruption of neuronal migration often lead to cortical dysfunction and/or malformation associated with neurological disorders. Unveiling the molecular control of neuronal migration is thus fundamental to understand the physiological or pathological development of the cerebral cortex. Generation of functional cortical neurons is a complex and stratified process that relies on decision of neural progenitors to leave the cell cycle and generate neurons that migrate and differentiate to reach their final position in the cortical wall. Although accumulating work shed some light on the molecular control of neuronal migration, we currently do not have a comprehensive understanding of how cell cycle exit and migration/differentiation are coordinated at the molecular level. The current chapter tends to lift the veil on this issue by discussing how core cell cycle regulators, and in particular p27(Kip1) acts as a multifunctional protein to control critical steps of neuronal migration through activities that go far beyond cell cycle regulation.
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22
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Avila A, Nguyen L, Rigo JM. Glycine receptors and brain development. Front Cell Neurosci 2013; 7:184. [PMID: 24155690 PMCID: PMC3800850 DOI: 10.3389/fncel.2013.00184] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 10/01/2013] [Indexed: 12/21/2022] Open
Abstract
Glycine receptors (GlyRs) are ligand-gated chloride ion channels that mediate fast inhibitory neurotransmission in the spinal cord and the brainstem. There, they are mainly involved in motor control and pain perception in the adult. However, these receptors are also expressed in upper regions of the central nervous system, where they participate in different processes including synaptic neurotransmission. Moreover, GlyRs are present since early stages of brain development and might influence this process. Here, we discuss the current state of the art regarding GlyRs during embryonic and postnatal brain development in light of recent findings about the cellular and molecular mechanisms that control brain development.
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Affiliation(s)
- Ariel Avila
- Cell Physiology, BIOMED Research Institute, Hasselt University Diepenbeek, Belgium ; Groupe Interdisciplinaire Génoprotéomique Appliquée-Neurosciences, Centre Hospitalier Universitaire Sart Tilman, University of Liége Liège, Belgium ; Groupe Interdisciplinaire Génoprotéomique Appliquée-Research, Centre Hospitalier Universitaire Sart Tilman, University of Liège Liège, Belgium
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23
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Kilb W, Kirischuk S, Luhmann HJ. Role of tonic GABAergic currents during pre- and early postnatal rodent development. Front Neural Circuits 2013; 7:139. [PMID: 24027498 PMCID: PMC3760143 DOI: 10.3389/fncir.2013.00139] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/16/2013] [Indexed: 11/13/2022] Open
Abstract
In the last three decades it became evident that the GABAergic system plays an essential role for the development of the central nervous system, by influencing the proliferation of neuronal precursors, neuronal migration and differentiation, as well as by controlling early activity patterns and thus formation of neuronal networks. GABA controls neuronal development via depolarizing membrane responses upon activation of ionotropic GABA receptors. However, many of these effects occur before the onset of synaptic GABAergic activity and thus require the presence of extrasynaptic tonic currents in neuronal precursors and immature neurons. This review summarizes our current knowledge about the role of tonic GABAergic currents during early brain development. In this review we compare the temporal sequence of the expression and functional relevance of different GABA receptor subunits, GABA synthesizing enzymes and GABA transporters. We also refer to other possible endogenous agonists of GABAA receptors. In addition, we describe functional consequences mediated by the GABAergic system during early developmental periods and discuss current models about the origin of extrasynaptic GABA and/or other endogenous GABAergic agonists during early developmental states. Finally, we present evidence that tonic GABAergic activity is also critically involved in the generation of physiological as well as pathophysiological activity patterns before and after the establishment of functional GABAergic synaptic connections.
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Affiliation(s)
- Werner Kilb
- Institute of Physiology and Pathophysiology, University Medical Center, Johannes Gutenberg University Mainz, Germany
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24
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Glycine receptor α2 subunit activation promotes cortical interneuron migration. Cell Rep 2013; 4:738-50. [PMID: 23954789 PMCID: PMC3763372 DOI: 10.1016/j.celrep.2013.07.016] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 06/17/2013] [Accepted: 07/12/2013] [Indexed: 12/11/2022] Open
Abstract
Glycine receptors (GlyRs) are detected in the developing CNS before synaptogenesis, but their function remains elusive. This study demonstrates that functional GlyRs are expressed by embryonic cortical interneurons in vivo. Furthermore, genetic disruption of these receptors leads to interneuron migration defects. We discovered that extrasynaptic activation of GlyRs containing the α2 subunit in cortical interneurons by endogenous glycine activates voltage-gated calcium channels and promotes calcium influx, which further modulates actomyosin contractility to fine-tune nuclear translocation during migration. Taken together, our data highlight the molecular events triggered by GlyR α2 activation that control cortical tangential migration during embryogenesis.
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25
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Berg DA, Belnoue L, Song H, Simon A. Neurotransmitter-mediated control of neurogenesis in the adult vertebrate brain. Development 2013; 140:2548-61. [PMID: 23715548 DOI: 10.1242/dev.088005] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
It was long thought that no new neurons are added to the adult brain. Similarly, neurotransmitter signaling was primarily associated with communication between differentiated neurons. Both of these ideas have been challenged, and a crosstalk between neurogenesis and neurotransmitter signaling is beginning to emerge. In this Review, we discuss neurotransmitter signaling as it functions at the intersection of stem cell research and regenerative medicine, exploring how it may regulate the formation of new functional neurons and outlining interactions with other signaling pathways. We consider evolutionary and cross-species comparative aspects, and integrate available results in the context of normal physiological versus pathological conditions. We also discuss the potential role of neurotransmitters in brain size regulation and implications for cell replacement therapies.
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Affiliation(s)
- Daniel A Berg
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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26
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Díaz-Alonso J, Guzmán M, Galve-Roperh I. Endocannabinoids via CB₁ receptors act as neurogenic niche cues during cortical development. Philos Trans R Soc Lond B Biol Sci 2013; 367:3229-41. [PMID: 23108542 DOI: 10.1098/rstb.2011.0385] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
During brain development, neurogenesis is precisely regulated by the concerted action of intrinsic factors and extracellular signalling systems that provide the necessary niche information to proliferating and differentiating cells. A number of recent studies have revealed a previously unknown role for the endocannabinoid (ECB) system in the control of embryonic neuronal development and maturation. Thus, the CB(1) cannabinoid receptor in concert with locally produced ECBs regulates neural progenitor (NP) proliferation, pyramidal specification and axonal navigation. In addition, subcellularly restricted ECB production acts as an axonal growth cone signal to regulate interneuron morphogenesis. These findings provide the rationale for understanding better the consequences of prenatal cannabinoid exposure, and emphasize a novel role of ECBs as neurogenic instructive cues involved in cortical development. In this review the implications of altered CB(1)-receptor-mediated signalling in developmental disorders and particularly in epileptogenesis are briefly discussed.
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Affiliation(s)
- Javier Díaz-Alonso
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto Ramón y Cajal de Investigación Sanitaria, Madrid, Spain
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27
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Jansson LC, Louhivuori L, Wigren HK, Nordström T, Louhivuori V, Castrén ML, Åkerman KE. Effect of glutamate receptor antagonists on migrating neural progenitor cells. Eur J Neurosci 2013; 37:1369-82. [PMID: 23383979 DOI: 10.1111/ejn.12152] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 01/10/2013] [Accepted: 01/10/2013] [Indexed: 02/03/2023]
Abstract
Neurotransmitters such as glutamate are potential regulators of neurogenesis. Interference with defined glutamate receptor subtypes affects proliferation, migration and differentiation of neural progenitor cells. The cellular targets for the actions of different glutamate receptor ligands are less well known. In this study we have combined calcium imaging, measurement of membrane potential, time-lapse imaging and immunocytochemistry to obtain a spatial overview of migrating mouse embryonic neural progenitor cell-derived cells responding to glutamate receptor agonists and antagonists. Responses via metabotropic glutamate receptor 5 correlated with radial glial cells and dominated in the inner migration zones close to the neurosphere. Block of metabotropic glutamate receptor 5 resulted in shorter radial glial processes, a transient increase in neuron-like cells emerging from the neurosphere and increased motility of neuron-like cells. α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptors are present on the majority of migrating neuronal cells, which with time accumulate at the outer edge of the migration zone. Blocking these receptors leads to an enhanced extension of radial glial processes and a reduced motility of neuron-like cells. Our results indicate that functional glutamate receptors have profound effects on the motility of neural progenitor cells. The main target for metabotropic glutamate receptor 5 appears to be radial glial cells while AMPA/kainate receptors are mainly expressed in newborn neuronal cells and regulate the migratory progress of these cells. The results suggest that both metabotropic glutamate receptor 5 and AMPA/kainate receptors are of importance for the guidance of migrating embryonic progenitor cells.
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Affiliation(s)
- Linda C Jansson
- Biomedicum Helsinki, Institute of Biomedicine/Physiology, University of Helsinki, Helsinki, Finland
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28
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Palanisamy A. Maternal anesthesia and fetal neurodevelopment. Int J Obstet Anesth 2012; 21:152-62. [DOI: 10.1016/j.ijoa.2012.01.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 01/21/2012] [Accepted: 01/28/2012] [Indexed: 12/01/2022]
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29
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Abstract
Millions of human infants receive general anesthetics for surgery or diagnostic procedures every year worldwide, and there is a growing inquietude regarding the safety of these drugs for the developing brain. In fact, accumulating experimental evidence together with recent epidemiologic observations suggest that general anesthetics might exert undesirable effects on the immature nervous system. The goal of this review is to highlight basic science issues as well as to critically present experimental data and clinical observations relevant to this possibility. By acting on a plethora of ligand-gated ion channels, general anesthetics are powerful modulators of neural activity. Since even brief interference with physiologic activity patterns during critical periods of development are known to induce permanent alterations in brain circuitry, anesthetic-induced interference with brain development is highly plausible. In line with this hypothesis, compelling experimental evidence, from rodents to primates, suggests increased neuroapoptosis and associated long-term neurocognitive deficits following administration of these drugs at defined stages of development. Recent epidemiologic studies also indicate a potential association between anesthesia/surgery and subsequently impaired neurocognitive function in humans. It is, however, important to note that extrapolation of experimental studies to human practice requires extreme caution, and that currently available human data are hindered by a large number of potentially confounding factors. Thus, despite significant advances in the field, there is still insufficient evidence to determine whether anesthetics are harmful to the developing human brain. Consequently, no change in clinical practice can be recommended.
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Affiliation(s)
- Laszlo Vutskits
- Pediatric Anesthesia Unit, Department of Anesthesiology, Pharmacology and Intensive Care, University Hospital of Geneva, Geneva, Switzerland.
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30
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Dash-Wagh S, Neumann JR, Veitinger S, Grote-Westrick C, Landgraf P, Pape HC, Kreutz MR, von Holst A, Wahle P. The survival promoting peptide Y-P30 promotes cellular migration. Mol Cell Neurosci 2011; 48:195-204. [PMID: 21820515 DOI: 10.1016/j.mcn.2011.07.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 06/01/2011] [Accepted: 07/14/2011] [Indexed: 11/25/2022] Open
Abstract
Y-P30, the 30 amino acid N-terminal peptide of the dermcidin gene, has been found to promote neuronal survival and differentiation. Its early presence in development and import to the fetal brain led to the hypothesis that Y-P30 has an influence on proliferation, differentiation and migration. Neurospheres derived from neural stem cells isolated from E13 mouse cortex and striatal ganglionic eminences were treated with Y-P30, however, the proportion of progenitors, neurons and astrocytes generated in differentiation assays was not altered. A short Y-P30 treatment of undifferentiated striatal and cortical neurospheres failed to alter the proportion of BrdU-positive cells. A longer treatment reduced the percentage of BrdU-positive cells and GABA-immunoreactive neurons only in striatal spheres. The presence of Y-P30 enhanced migration of T24 human bladder carcinoma cells in a wound-healing assay in vitro. Further, Y-P30 enhanced migration of T24 cells, rat primary cortical astrocytes and PC12 cells in chemotactic Boyden chamber assays. Together, these findings suggest that a major function of Y-P30 is to promote migration of neural and non-neural cell types.
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Affiliation(s)
- Suvarna Dash-Wagh
- AG Developmental Neurobiology, Faculty for Biology and Biotechnology, Ruhr-University Bochum, Germany
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31
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Jovanovic JN, Thomson AM. Development of cortical GABAergic innervation. Front Cell Neurosci 2011; 5:14. [PMID: 21808605 PMCID: PMC3139172 DOI: 10.3389/fncel.2011.00014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 06/28/2011] [Indexed: 01/02/2023] Open
Abstract
The mature neocortex contains many different classes of GABAergic inhibitory interneurons, distributed, with some degree of selectivity, through six layers, and through many different regions. Some of the events in the early lives of these neurones that may determine their ultimate destination, their maturation and their selective innervation of targets appropriate for each subtype, are discussed. Both time and place of birth influence the class of interneuron that an early post-mitotic interneuronal precursor will become, driven by the selective expression of different combinations of transcription factors in different regions of their birth places in the ganglionic eminence and ventricular zone. The long distance migration of these precursors along tangential routes in marginal, subventricular, and intermediate zones and their final radial movement, into the developing cortex, is regulated by chemical cues, both attractant and repellent. Once they arrive at their final destination, they must integrate into the developing circuitry. As they mature within the cortex, their axons grow and branch in highly specific patterns that may be partially determined by the genetic blueprint for each interneuronal class and partly by the environment in which they find themselves. Finally, as each interneuron class begins to form synapses with only certain postsynaptic targets, cell–cell recognition, most probably via protein–protein interactions across the synaptic cleft, facilitate the formation of appropriate synapses.
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32
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Namba T, Ming GL, Song H, Waga C, Enomoto A, Kaibuchi K, Kohsaka S, Uchino S. NMDA receptor regulates migration of newly generated neurons in the adult hippocampus via Disrupted-In-Schizophrenia 1 (DISC1). J Neurochem 2011; 118:34-44. [PMID: 21517847 DOI: 10.1111/j.1471-4159.2011.07282.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In the mammalian brain, new neurons are continuously generated throughout life in the dentate gyrus (DG) of the hippocampus. Previous studies have established that newborn neurons migrate a short distance to be integrated into a pre-existing neuronal circuit in the hippocampus. How the migration of newborn neurons is governed by extracellular signals, however, has not been fully understood. Here, we report that NMDA receptor (NMDA-R)-mediated signaling is essential for the proper migration and positioning of newborn neurons in the DG. An intraperitoneal injection of the NMDA-R antagonists, memantine, or 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) into adult male mice caused the aberrant positioning of newborn neurons, resulting in the overextension of their migration in the DG. Interestingly, we revealed that the administration of NMDA-R antagonists leads to a decrease in the expression of Disrupted-In-Schizophrenia 1 (DISC1), a candidate susceptibility gene for major psychiatric disorders such as schizophrenia, which is also known as a critical regulator of neuronal migration in the DG. Furthermore, the overextended migration of newborn neurons induced by the NMDA-R antagonists was significantly rescued by exogenous expression of DISC1. Collectively, these results suggest that the NMDA-R signaling pathway governs the migration of newborn neurons via the regulation of DISC1 expression in the DG.
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Affiliation(s)
- Takashi Namba
- Department of Neurochemistry, National Institute of Neuroscience, Tokyo, Japan
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Montiel JF, Wang WZ, Oeschger FM, Hoerder-Suabedissen A, Tung WL, García-Moreno F, Holm IE, Villalón A, Molnár Z. Hypothesis on the dual origin of the Mammalian subplate. Front Neuroanat 2011; 5:25. [PMID: 21519390 PMCID: PMC3078748 DOI: 10.3389/fnana.2011.00025] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 03/25/2011] [Indexed: 12/23/2022] Open
Abstract
The development of the mammalian neocortex relies heavily on subplate. The proportion of this cell population varies considerably in different mammalian species. Subplate is almost undetectable in marsupials, forms a thin, but distinct layer in mouse and rat, a larger layer in carnivores and big-brained mammals as pig, and a highly developed embryonic structure in human and non-human primates. The evolutionary origin of subplate neurons is the subject of current debate. Some hypothesize that subplate represents the ancestral cortex of sauropsids, while others consider it to be an increasingly complex phylogenetic novelty of the mammalian neocortex. Here we review recent work on expression of several genes that were originally identified in rodent as highly and differentially expressed in subplate. We relate these observations to cellular morphology, birthdating, and hodology in the dorsal cortex/dorsal pallium of several amniote species. Based on this reviewed evidence we argue for a third hypothesis according to which subplate contains both ancestral and newly derived cell populations. We propose that the mammalian subplate originally derived from a phylogenetically ancient structure in the dorsal pallium of stem amniotes, but subsequently expanded with additional cell populations in the synapsid lineage to support an increasingly complex cortical plate development. Further understanding of the detailed molecular taxonomy, somatodendritic morphology, and connectivity of subplate in a comparative context should contribute to the identification of the ancestral and newly evolved populations of subplate neurons.
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Affiliation(s)
- Juan F Montiel
- Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK
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Lee CT, Chen J, Worden LT, Freed WJ. Cocaine causes deficits in radial migration and alters the distribution of glutamate and GABA neurons in the developing rat cerebral cortex. Synapse 2011; 65:21-34. [PMID: 20506319 PMCID: PMC2965825 DOI: 10.1002/syn.20814] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Prenatal cocaine exposure induces cytoarchitectural changes in the embryonic neocortex; however, the biological mechanisms and type of cortical neurons involved in these changes are not known. Previously, we found that neural progenitor proliferation in the neocortical ventricular zone (VZ) is inhibited by cocaine; here, we examine the changes in cortical neurogenesis and migration of glutamate and GABA neurons induced by prenatal cocaine exposure. Pregnant rats received 20 mg/kg of cocaine intraperitoneally twice at an interval of 12 h during three periods of neocortical neurogenesis. Neocortical area and distribution of developing neurons were examined by counting Tuj1+, glutamate+, or GABA+ cells in different areas of the cerebral cortex. Cocaine decreased neocortical area by reducing the size of the Tuj1+ layer, but only when administered during early periods of neocortical neurogenesis. The number of glutamatergic neurons was increased in the VZ but was decreased in the outer cortical laminae. Although the number of GABA+ neurons in the VZ of both the neocortex and ganglionic eminences was unchanged, GABA+ cells decreased in all other neocortical laminae. Tangential migration of GABA+ cells was also disrupted by cocaine. These findings suggest that in utero cocaine exposure disturbs radial migration of neocortical neurons, possibly because of decreased radial glia guiding support through enhanced differentiation of neocortical VZ progenitors. Cocaine interrupts radial migration of both glutamatergic and GABAergic neurons within the neocortex, in addition to the tangential migration of GABAergic neurons from the subcortical telecephalon. This may result in abnormal neocortical cytoarchitecture and concomitant adverse functional effects.
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Affiliation(s)
- Chun-Ting Lee
- Development and Plasticity Section, Cellular Neurobiology Branch, Intramural Research Program (IRP), National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), Department of Health and Human Services, Baltimore, Maryland 21224, USA.
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35
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Gumera C, Rauck B, Wang Y. Materials for central nervous system regeneration: bioactive cues. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c0jm04335d] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Cuzon Carlson VC, Yeh HH. GABAA receptor subunit profiles of tangentially migrating neurons derived from the medial ganglionic eminence. Cereb Cortex 2010; 21:1792-802. [PMID: 21148088 DOI: 10.1093/cercor/bhq247] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
During rodent corticogenesis, a sizeable subpopulation of γ-aminobutyric acid (GABA)ergic interneurons arises extracortically from the medial ganglionic eminence (MGE). These neurons progressively acquire responsiveness to GABA in the course of corticopetal tangential migration, a process regulated by ambient GABA and mediated by GABA(A) receptors. Here, we combined patch clamp electrophysiology and single-cell reverse transcription-polymerase chain reaction to examine GABA(A) receptor expression in green fluorescent MGE-derived (eGFP+) cells in telencephalic slices from gestational day 14.5 BAC-Lhx6 embryos. GABA concentration-response curves revealed lower apparent affinity and efficacy in eGFP+ cells in and around the MGE than their counterparts in the cortex. Pharmacological tests revealed subunit-selective response profiles in the MGE and cortex consistent with differential expression of GABA(A) receptor isoforms. Profiling of GABA(A) receptor subunit transcripts (α1-5, β1-3, and γ1-3, δ) uncovered increased expression of the α1-, α2-, α5-, γ2-, and γ3-subunit messenger RNAs in the cortex. We propose that the dynamic expression of certain GABA(A) receptor subunits contributes to assembling receptor isoforms that confer functional attributes important in regulating the migration and maturation of primordial GABAergic cortical interneurons.
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Affiliation(s)
- Verginia C Cuzon Carlson
- Department of Physiology and Neurobiology, Dartmouth Medical School, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA
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Brain-derived neurotrophic factor mediates non-cell-autonomous regulation of sensory neuron position and identity. J Neurosci 2010; 30:14513-21. [PMID: 20980609 DOI: 10.1523/jneurosci.4025-10.2010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
During development, neurons migrate considerable distances to reside in locations that enable their individual functional roles. Whereas migration mechanisms have been extensively studied, much less is known about how neurons remain in their ideal locations. We sought to identify factors that maintain the position of postmigratory dorsal root ganglion neurons, neural crest derivatives for which migration and final position play an important developmental role. We found that an early developing population of sensory neurons maintains the position of later born dorsal root ganglia neurons in an activity-dependent manner. Further, inhibiting or increasing the function of brain-derived neurotrophic factor induces or prevents, respectively, migration of dorsal root ganglia neurons out of the ganglion to locations where they acquire a new identity. Overall, the results demonstrate that neurotrophins mediate non-cell-autonomous maintenance of position and thereby the identity of differentiated neurons.
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Actomyosin contraction at the cell rear drives nuclear translocation in migrating cortical interneurons. J Neurosci 2010; 30:8660-70. [PMID: 20573911 DOI: 10.1523/jneurosci.1962-10.2010] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Neuronal migration is a complex process requiring the coordinated interaction of cytoskeletal components and regulated by calcium signaling among other factors. Migratory neurons are polarized cells in which the largest intracellular organelle, the nucleus, has to move repeatedly. Current views support a central role for pulling forces that drive nuclear movement. The participation of actomyosin driven forces acting at the nucleus rear has been suggested, however its precise contribution has not been directly addressed. By analyzing interneurons migrating in cortical slices of mouse brains, we have found that nucleokinesis is associated with a precise pattern of actin dynamics characterized by the initial formation of a cup-like actin structure at the rear nuclear pole. Time-lapse experiments show that progressive actomyosin contraction drives the nucleus forward. Nucleokinesis concludes with the complete contraction of the cup-like structure, resulting in an actin spot at the base of the retracting trailing process. Our results demonstrate that this actin remodeling requires a threshold calcium level provided by low-frequency spontaneous fast intracellular calcium transients. Microtubule stabilization with taxol treatment prevents actin remodeling and nucleokinesis, whereas cells with a collapsed microtubule cytoskeleton induced by nocodazole treatment, display nearly normal actin dynamics and nucleokinesis. In summary, the results presented here demonstrate that actomyosin forces acting at the rear side of the nucleus drives nucleokinesis in tangentially migrating interneurons in a process that requires calcium and a dynamic cytoskeleton of microtubules.
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Schubert T, Huckfeldt RM, Parker E, Campbell JE, Wong ROL. Assembly of the outer retina in the absence of GABA synthesis in horizontal cells. Neural Dev 2010; 5:15. [PMID: 20565821 PMCID: PMC2919532 DOI: 10.1186/1749-8104-5-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Accepted: 06/18/2010] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The inhibitory neurotransmitter gamma-amino-butyric acid (GABA) not only modulates excitability in the mature nervous system but also regulates neuronal differentiation and circuit development. Horizontal cells, a subset of interneurons in the outer retina, are transiently GABAergic during the period of cone photoreceptor synaptogenesis. In rodents, both horizontal cells and cone axonal terminals express GABAA receptors. To explore the possibility that transient GABA expression in mouse neonatal horizontal cells influences the structural development of synaptic connectivity in the outer retina, we examined a mutant in which expression of GAD67, the major synthesizing enzyme for GABA, is selectively knocked out in the retina. RESULTS Immunocytochemistry and electron microscopy revealed that the assembly of triad synapses involving cone axonal pedicles and the dendrites of horizontal and bipolar cells is unaffected in the mutant retina. Moreover, loss of GABA synthesis in the outer retina did not perturb the spatial distributions and cell densities of cones and horizontal cells. However, there were some structural alterations at the cellular level: the average size of horizontal cell dendritic clusters was larger in the mutant, and there was also a small but significant increase in cone photoreceptor pedicle area. Moreover, metabotropic glutamate receptor 6 (mGluR6) receptors on the dendrites of ON bipolar cells occupied a slightly larger proportion of the cone pedicle in the mutant. CONCLUSIONS Together, our analysis shows that transient GABA synthesis in horizontal cells is not critical for synapse assembly and axonal and dendritic lamination in the outer retina. However, pre- and postsynaptic structures are somewhat enlarged in the absence of GABA in the developing outer retina, providing for a modest increase in potential contact area between cone photoreceptors and their targets. These findings differ from previous results in which pharmacological blockade of GABAA receptors in the neonatal rabbit retina caused a reduction in cone numbers and led to a grossly disorganized outer retina.
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Affiliation(s)
- Timm Schubert
- Department of Biological Structure, University of Washington, School of Medicine, 1959 NE Pacific St, Seattle, WA 98195, USA
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Inhibition of N-methyl-D-aspartate receptor activity resulted in aberrant neuronal migration caused by delayed morphological development in the mouse neocortex. Neuroscience 2010; 169:609-18. [PMID: 20497907 DOI: 10.1016/j.neuroscience.2010.05.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 05/10/2010] [Accepted: 05/12/2010] [Indexed: 11/24/2022]
Abstract
Embryonic and neonatal neocortical neurons already express functional N-methyl-D-aspartate (NMDA) receptors before they form synapses. To elucidate the role of NMDA receptors in neuronal migration in the developing neocortex, we visualized radially migrating neurons by transferring the enhanced green fluorescent protein (EGFP) gene into the ventricular zone (VZ) of the mouse neocortex using in utero electroporation at E15.5. Two days later, we prepared neocortical slices and examined the EGFP-positive cells using time-lapse imaging in the presence of the NMDA receptor antagonist Cerestat. The EGFP-positive cells generated in the VZ in the control slices exhibited a multipolar morphology, but within several hours they became bipolar (with a leading process and an axon-like process) and migrated toward the pial surface. By contrast, many of the multipolar cells in the Cerestat-treated slices failed to extend either process and become bipolar, and frequently changed direction, although they ultimately reached their destination even after Cerestat-treatment. To identify the molecules responding for mediating NMDA signaling during neuronal migration and the changes in morphology observed above, we here focused on Src family kinases (SFKs), which mediate a variety of neuronal functions including migration and neurite extension. We discovered that the activity of Src and Fyn was reduced by Cerestat. These findings suggest that NMDA receptors are involved in neuronal migration and morphological changes into a bipolar shape, and in the activation of Src and Fyn in the developing neocortex.
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Hao MM, Moore RE, Roberts RR, Nguyen T, Furness JB, Anderson RB, Young HM. The role of neural activity in the migration and differentiation of enteric neuron precursors. Neurogastroenterol Motil 2010; 22:e127-37. [PMID: 20082666 DOI: 10.1111/j.1365-2982.2009.01462.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND As they migrate through the developing gut, a sub-population of enteric neural crest-derived cells (ENCCs) begins to differentiate into neurons. The early appearance of neurons raises the possibility that electrical activity and neurotransmitter release could influence the migration or differentiation of ENNCs. METHODS The appearance of neuronal sub-types in the gut of embryonic mice was examined using immunohistochemistry. The effects of blocking various forms of neural activity on ENCC migration and neuronal differentiation were examined using explants of cultured embryonic gut. KEY RESULTS Nerve fibers were present in close apposition to many ENCCs. Commencing at E11.5, neuronal nitric oxide synthase (nNOS), calbindin and IK(Ca) channel immunoreactivities were shown by sub-populations of enteric neurons. In cultured explants of embryonic gut, tetrodotoxin (TTX, an inhibitor of action potential generation), nitro-L-arginine (NOLA, an inhibitor of nitric oxide synthesis) and clotrimazole (an IK(Ca) channel blocker) did not affect the rate of ENCC migration, but tetanus toxin (an inhibitor of SNARE-mediated vesicle fusion) significantly impaired ENCC migration as previously reported. In explants of E11.5 and E12.5 hindgut grown in the presence of TTX or tetanus toxin there was a decrease in the number nNOS+ neurons close to the migratory wavefront, but no significant difference in the proportion of all ENCC that expressed the pan-neuronal marker, Hu. CONCLUSIONS & INFERENCES (i) Some enteric neuron sub-types are present very early during the development of the enteric nervous system. (ii) The rate of differentiation of some sub-types of enteric neurons appears to be influenced by TTX- and tetanus toxin-sensitive mechanisms.
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Affiliation(s)
- M M Hao
- Department of Anatomy & Cell Biology, University of Melbourne, Vic., Australia
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42
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GABAC receptors are functionally expressed in the intermediate zone and regulate radial migration in the embryonic mouse neocortex. Neuroscience 2010; 167:124-34. [DOI: 10.1016/j.neuroscience.2010.01.049] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 01/09/2010] [Accepted: 01/25/2010] [Indexed: 10/19/2022]
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Molecules and mechanisms involved in the generation and migration of cortical interneurons. ASN Neuro 2010; 2:e00031. [PMID: 20360946 PMCID: PMC2847827 DOI: 10.1042/an20090053] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 03/04/2010] [Accepted: 03/05/2010] [Indexed: 11/30/2022] Open
Abstract
The GABA (γ-aminobutyric acid)-containing interneurons of the neocortex are largely derived from the ganglionic eminences in the subpallium. Numerous studies have previously defined the migratory paths travelled by these neurons from their origins to their destinations in the cortex. We review here results of studies that have identified many of the genes expressed in the subpallium that are involved in the specification of the subtypes of cortical interneurons, and the numerous transcription factors, motogenic factors and guidance molecules that are involved in their migration.
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Key Words
- 5-HT, 5-hydroxytryptamine
- AEP, anterior entopeduncular
- BDNF, brain-derived neurotrophic factor
- CGE, caudal ganglionic eminence
- CP, cortical plate
- CR, calretinin
- CXCR, CXC chemokine receptor
- E, embryonic day
- GABA, γ-aminobutyric acid
- GABAR, GABA receptor
- HGF/SF, hepatocyte growth factor/scatter factor
- IZ, intermediate zone
- LGE, lateral ganglionic eminence
- MGE, medial ganglionic eminence
- MZ, marginal zone
- NGR, neuregulin
- NPY, neuropeptide Y
- Nrp, neuropilin
- POA, preoptic area
- PV, paravalbumin
- Robo, Roundabout
- SDF-1, stromal-derived factor 1
- SHH, sonic hedgehog
- SST, somatostatin
- SVZ, subventricular zone
- VZ, ventricular zone
- gene expression
- interneuron
- migration
- neocortex
- neuronal specification
- subpallium
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Friocourt G, Parnavelas JG. Mutations in ARX Result in Several Defects Involving GABAergic Neurons. Front Cell Neurosci 2010; 4:4. [PMID: 20300201 PMCID: PMC2841486 DOI: 10.3389/fncel.2010.00004] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 02/24/2010] [Indexed: 01/15/2023] Open
Abstract
Genetic investigations of X-linked mental retardation have demonstrated the implication of ARX in a wide spectrum of disorders extending from phenotypes with severe neuronal migration defects, such as lissencephaly, to mild or moderate forms of mental retardation without apparent brain abnormalities, but with associated features of dystonia and epilepsy. These investigations have in recent years directed attention to the role of this gene in brain development. Analysis of its spatio-temporal localization profile revealed expression in telencephalic structures at all stages of development, mainly restricted to populations of GABA-containing neurons. Furthermore, studies of the effects of ARX loss of function either in humans or in lines of mutant mice revealed varying defects, suggesting multiple roles of this gene during development. In particular, Arx has been shown to contribute to almost all fundamental processes of brain development: patterning, neuronal proliferation and migration, cell maturation and differentiation, as well as axonal outgrowth and connectivity. In this review, we will present and discuss recent findings concerning the role of ARX in brain development and how this information will be useful to better understand the pathophysiological mechanisms of mental retardation and epilepsy associated with ARX mutations.
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Affiliation(s)
- Gaëlle Friocourt
- U613, Institut National de la Santé et de la Recherche Médicale Brest, France
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45
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Isayama RN, Leite PEC, Lima JPM, Uziel D, Yamasaki EN. Impact of ethanol on the developing GABAergic system. Anat Rec (Hoboken) 2010; 292:1922-39. [PMID: 19943346 DOI: 10.1002/ar.20966] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Alcohol intake during pregnancy has a tremendous impact on the developing brain. Embryonic and early postnatal alcohol exposures have been investigated experimentally to elucidate the fetal alcohol spectrum disorders' (FASD) milieu, and new data have emerged to support a devastating effect on the GABAergic system in the adult and developing nervous system. GABA is a predominantly inhibitory neurotransmitter that during development excites neurons and orchestrates several developmental processes such as proliferation, migration, differentiation, and synaptogenesis. This review summarizes and brings new data on neurodevelopmental aspects of the GABAergic system with FASD in experimental telencephalic models.
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Affiliation(s)
- Ricardo Noboro Isayama
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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46
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Petanjek Z, Kostović I, Esclapez M. Primate-specific origins and migration of cortical GABAergic neurons. Front Neuroanat 2009; 3:26. [PMID: 20011218 PMCID: PMC2790953 DOI: 10.3389/neuro.05.026.2009] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 10/16/2009] [Indexed: 02/02/2023] Open
Abstract
Gamma-aminobutyric-acidergic (GABAergic) cells form a very heterogeneous population of neurons that play a crucial role in the coordination and integration of cortical functions. Their number and diversity increase through mammalian brain evolution. Does evolution use the same or different developmental rules to provide the increased population of cortical GABAergic neurons? In rodents, these neurons are not generated in the pallial proliferative zones as glutamatergic principal neurons. They are produced almost exclusively by the subpallial proliferative zones, the ganglionic eminence (GE) and migrate tangentially to reach their target cortical layers. The GE is organized in molecularly different subdomains that produce different subpopulations of cortical GABAergic neurons. In humans and non-human primates, in addition to the GE, cortical GABAergic neurons are also abundantly generated by the proliferative zones of the dorsal telencephalon. Neurogenesis in ventral and dorsal telencephalon occurs with distinct temporal profiles. These dorsal and ventral lineages give rise to different populations of GABAergic neurons. Early-generated GABAergic neurons originate from the GE and mostly migrate to the marginal zone and the subplate. Later-generated GABAergic neurons, originating from both proliferative sites, populate the cortical plate. Interestingly, the pool of GABAergic progenitors in dorsal telencephalon produces mainly calretinin neurons, a population known to be significantly increased and to display specific features in primates. We conclude that the development of cortical GABAergic neurons have exclusive features in primates that need to be considered in order to understand pathological mechanisms leading to some neurological and psychiatric diseases.
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Affiliation(s)
- Zdravko Petanjek
- Department of Neuroscience, Croatian Institute for Brain Research, School of Medicine, University of Zagreb Zagreb, Croatia
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Jaglin XH, Chelly J. Tubulin-related cortical dysgeneses: microtubule dysfunction underlying neuronal migration defects. Trends Genet 2009; 25:555-66. [PMID: 19864038 DOI: 10.1016/j.tig.2009.10.003] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 10/02/2009] [Accepted: 10/03/2009] [Indexed: 01/14/2023]
Abstract
The fine tuning of proliferation and neurogenesis, neuronal migration and differentiation and connectivity underlies the proper development of the cerebral cortex. Mutations in genes involved in these processes are responsible for neurodevelopmental disorders, such as cortical dysgeneses, which are usually associated with severe mental retardation and epilepsy. Over the past few years, the importance of cytoskeleton components in cellular processes crucial for cortical development has emerged from a body of functional data. This was reinforced by the association of mutations in the LIS1 and DCX genes, which both encode proteins involved in microtubule (MT) homeostasis, with cerebral cortex developmental disorders. The recent discovery of patients with lissencephaly and bilateral asymmetrical polymicrogyria (PMG) carrying mutations in the alpha- and beta-tubulin-encoding genes TUBA1A and TUBB2B further supports this view, and also raises interesting questions about the specific roles played by certain tubulin isotypes during the development of the cortex.
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Affiliation(s)
- Xavier H Jaglin
- Institut Cochin, Université Paris Descartes, CNRS (UMR 8104), Paris, France
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Rosales FJ, Reznick JS, Zeisel SH. Understanding the role of nutrition in the brain and behavioral development of toddlers and preschool children: identifying and addressing methodological barriers. Nutr Neurosci 2009; 12:190-202. [PMID: 19761650 PMCID: PMC2776771 DOI: 10.1179/147683009x423454] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The preschool years (i.e. 1-5 years of age) is a time of rapid and dramatic postnatal brain development (i.e. neural plasticity), and of fundamental acquisition of cognitive development (i.e. working memory, attention and inhibitory control). Also, it is a time of transition from a direct maternal mediation/selection of diet-based nutrition to food selection that is more based on self-selection and self-gratification. However, there have been fewer published studies in preschool children than in infants or school-aged children that examined the role of nutrition in brain/mental development (125 studies versus 232 and 303 studies, respectively during the last 28 years). This may arise because of age-related variability, in terms of individual differences in temperament, linguistic ability, and patterns of neural activity that may affect assessment of neural and cognitive development in pre-school children. In this review, we suggest several approaches for assessing brain function in children that can be refined. It would be desirable if the discipline developed some common elements to be included in future studies of diet and brain function, with the idea that they would complement more targeted measures based on time of exposure and understanding of data from animal models. Underlining this approach is the concept of 'window of sensitivity' during which nutrients may affect postnatal neural development: investigators and expert panels need to look specifically for region-specific changes and do so with understanding of the likely time window during which the nutrient was, or was not available.
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Affiliation(s)
- Francisco J Rosales
- Global Research and Development, Mead Johnson Nutritionals, Evansville, Indiana, USA.
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Abstract
The fetal brain is a dynamic structure, which can now be imaged using magnetic resonance imaging (MRI). This article will review techniques of fetal MRI as well as several key aspects of brain development and their appearance on MRI. An understanding of normal fetal brain development is essential to correctly identifying developmental abnormalities.
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Affiliation(s)
- Orit A Glenn
- Department of Radiology, Neuroradiology Section, University of California, San Francisco, CA 94143, USA.
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50
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Tong XP, Li XY, Zhou B, Shen W, Zhang ZJ, Xu TL, Duan S. Ca(2+) signaling evoked by activation of Na(+) channels and Na(+)/Ca(2+) exchangers is required for GABA-induced NG2 cell migration. ACTA ACUST UNITED AC 2009; 186:113-28. [PMID: 19596850 PMCID: PMC2712990 DOI: 10.1083/jcb.200811071] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
NG2 cells originate from various brain regions and migrate to their destinations during early development. These cells express voltage-gated Na(+) channels but fail to produce typical action potentials. The physiological role of Na(+) channels in these cells is unclear. We found that GABA induces membrane depolarization and Ca(2+) elevation in NG2 cells, a process requiring activation of GABA(A) receptors, Na(+) channels, and Na(+)/Ca(2+) exchangers (NCXs), but not Ca(2+) channels. We have identified a persistent Na(+) current in these cells that may underlie the GABA-induced pathway of prolonged Na(+) elevation, which in turn triggers Ca(2+) influx via NCXs. This unique Ca(2+) signaling pathway is further shown to be involved in the migration of NG2 cells. Thus, GABAergic signaling mediated by sequential activation of GABA(A) receptors, noninactivating Na(+) channels, and NCXs may play an important role in the development and function of NG2 glial cells in the brain.
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Affiliation(s)
- Xiao-ping Tong
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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