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Tomàs J, Cilleros-Mañé V, Just-Borràs L, Balanyà-Segura M, Polishchuk A, Nadal L, Tomàs M, Silvera-Simón C, Santafé MM, Lanuza MA. Brain-derived neurotrophic factor signaling in the neuromuscular junction during developmental axonal competition and synapse elimination. Neural Regen Res 2025; 20:394-401. [PMID: 38819042 DOI: 10.4103/1673-5374.391314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/16/2023] [Indexed: 06/01/2024] Open
Abstract
During the development of the nervous system, there is an overproduction of neurons and synapses. Hebbian competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or strengthening. We have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway, at the neuromuscular junction, in the axonal development and synapse elimination process versus the synapse consolidation. The purpose of this review is to describe the neurotrophic influence on developmental synapse elimination, in relation to other molecular pathways that we and others have found to regulate this process. In particular, we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors, coupled to downstream serine-threonine protein kinases A and C (PKA and PKC) and voltage-gated calcium channels, at different nerve endings in developmental competition. The dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site, influence each other, and require careful studies to individualize the mechanisms of specific endings. We describe an activity-dependent balance (related to the extent of transmitter release) between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon terminals. The downstream displacement of the PKA/PKC activity ratio to lower values, both in competing nerve terminals and at postsynaptic sites, plays a relevant role in controlling the elimination of supernumerary synapses. Finally, calcium entry through L- and P/Q- subtypes of voltage-gated calcium channels (both channels are present, together with the N-type channel in developing nerve terminals) contributes to reduce transmitter release and promote withdrawal of the most unfavorable nerve terminals during elimination (the weakest in acetylcholine release and those that have already become silent). The main findings contribute to a better understanding of punishment-rewarding interactions between nerve endings during development. Identifying the molecular targets and signaling pathways that allow synapse consolidation or withdrawal of synapses in different situations is important for potential therapies in neurodegenerative diseases.
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Affiliation(s)
- Josep Tomàs
- Unitat d'Histologia i Neurobiologia (UHNeurob), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus, Spain
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2
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Shen G, Zhao D, Dong Y, Zeng Y. Brain-inspired neural circuit evolution for spiking neural networks. Proc Natl Acad Sci U S A 2023; 120:e2218173120. [PMID: 37729206 PMCID: PMC10523604 DOI: 10.1073/pnas.2218173120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 07/27/2023] [Indexed: 09/22/2023] Open
Abstract
In biological neural systems, different neurons are capable of self-organizing to form different neural circuits for achieving a variety of cognitive functions. However, the current design paradigm of spiking neural networks is based on structures derived from deep learning. Such structures are dominated by feedforward connections without taking into account different types of neurons, which significantly prevent spiking neural networks from realizing their potential on complex tasks. It remains an open challenge to apply the rich dynamical properties of biological neural circuits to model the structure of current spiking neural networks. This paper provides a more biologically plausible evolutionary space by combining feedforward and feedback connections with excitatory and inhibitory neurons. We exploit the local spiking behavior of neurons to adaptively evolve neural circuits such as forward excitation, forward inhibition, feedback inhibition, and lateral inhibition by the local law of spike-timing-dependent plasticity and update the synaptic weights in combination with the global error signals. By using the evolved neural circuits, we construct spiking neural networks for image classification and reinforcement learning tasks. Using the brain-inspired Neural circuit Evolution strategy (NeuEvo) with rich neural circuit types, the evolved spiking neural network greatly enhances capability on perception and reinforcement learning tasks. NeuEvo achieves state-of-the-art performance on CIFAR10, DVS-CIFAR10, DVS-Gesture, and N-Caltech101 datasets and achieves advanced performance on ImageNet. Combined with on-policy and off-policy deep reinforcement learning algorithms, it achieves comparable performance with artificial neural networks. The evolved spiking neural circuits lay the foundation for the evolution of complex networks with functions.
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Affiliation(s)
- Guobin Shen
- Brain-inspired Cognitive Intelligence Lab, Institute of Automation, Chinese Academy of Sciences, Beijing100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing100190, China
| | - Dongcheng Zhao
- Brain-inspired Cognitive Intelligence Lab, Institute of Automation, Chinese Academy of Sciences, Beijing100190, China
| | - Yiting Dong
- Brain-inspired Cognitive Intelligence Lab, Institute of Automation, Chinese Academy of Sciences, Beijing100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing100190, China
| | - Yi Zeng
- Brain-inspired Cognitive Intelligence Lab, Institute of Automation, Chinese Academy of Sciences, Beijing100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing100190, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Beijing100190, China
- School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing100190, China
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3
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Balena T, Lillis K, Rahmati N, Bahari F, Dzhala V, Berdichevsky E, Staley K. A Dynamic Balance between Neuronal Death and Clearance in an in Vitro Model of Acute Brain Injury. J Neurosci 2023; 43:6084-6107. [PMID: 37527922 PMCID: PMC10451151 DOI: 10.1523/jneurosci.0436-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/15/2023] [Accepted: 07/20/2023] [Indexed: 08/03/2023] Open
Abstract
In in vitro models of acute brain injury, neuronal death may overwhelm the capacity for microglial phagocytosis, creating a queue of dying neurons awaiting clearance. Neurons undergoing programmed cell death are in this queue, and are the most visible and frequently quantified measure of neuronal death after injury. However, the size of this queue should be equally sensitive to changes in neuronal death and the rate of phagocytosis. Using rodent organotypic hippocampal slice cultures as a model of acute perinatal brain injury, serial imaging demonstrated that the capacity for microglial phagocytosis of dying neurons was overwhelmed for 2 weeks. Altering phagocytosis rates (e.g., by changing the number of microglia) dramatically changed the number of visibly dying neurons. Similar effects were generated when the visibility of dying neurons was altered by changing the membrane permeability for stains that label dying neurons. Canonically neuroprotective interventions, such as seizure blockade, and neurotoxic maneuvers, such as perinatal ethanol exposure, were mediated by effects on microglial activity and the membrane permeability of neurons undergoing programmed cell death. These canonically neuroprotective and neurotoxic interventions had either no or opposing effects on healthy surviving neurons identified by the ongoing expression of transgenic fluorescent proteins.SIGNIFICANCE STATEMENT In in vitro models of acute brain injury, microglial phagocytosis is overwhelmed by the number of dying cells. Under these conditions, the assumptions on which assays for neuroprotective and neurotoxic effects are based are no longer valid. Thus, longitudinal assays of healthy cells, such as serial assessment of the fluorescence emission of transgenically expressed proteins, provide more accurate estimates of cell death than do single-time point anatomic or biochemical assays of the number of dying neurons. More accurate estimates of death rates in vitro will increase the translatability of preclinical studies of neuroprotection and neurotoxicity.
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Affiliation(s)
- Trevor Balena
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kyle Lillis
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Negah Rahmati
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Fatemeh Bahari
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Volodymyr Dzhala
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Eugene Berdichevsky
- Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, Pennsylvania 18015
| | - Kevin Staley
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
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4
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Huang TH, Lai MC, Chen YS, Huang CW. The Roles of Glutamate Receptors and Their Antagonists in Status Epilepticus, Refractory Status Epilepticus, and Super-Refractory Status Epilepticus. Biomedicines 2023; 11:biomedicines11030686. [PMID: 36979664 PMCID: PMC10045490 DOI: 10.3390/biomedicines11030686] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/18/2023] [Accepted: 02/21/2023] [Indexed: 03/30/2023] Open
Abstract
Status epilepticus (SE) is a neurological emergency with a high mortality rate. When compared to chronic epilepsy, it is distinguished by the durability of seizures and frequent resistance to benzodiazepine (BZD). The Receptor Trafficking Hypothesis, which suggests that the downregulation of γ-Aminobutyric acid type A (GABAA) receptors, and upregulation of N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors play major roles in the establishment of SE is the most widely accepted hypothesis underlying BZD resistance. NMDA and AMPA are ionotropic glutamate receptor families that have important excitatory roles in the central nervous system (CNS). They are both essential in maintaining the normal function of the brain and are involved in a variety of neuropsychiatric diseases, including epilepsy. Based on animal and human studies, antagonists of NMDA and AMPA receptors have a significant impact in ending SE; albeit most of them are not yet approved to be in clinically therapeutic guidelines, due to their psychomimetic adverse effects. Although there is still a dearth of randomized, prospective research, NMDA antagonists such as ketamine, magnesium sulfate, and the AMPA antagonist, perampanel, are regarded to be reasonable optional adjuvant therapies in controlling SE, refractory SE (RSE) or super-refractory SE (SRSE), though there are still a lack of randomized, prospective studies. This review seeks to summarize and update knowledge on the SE development hypothesis, as well as clinical trials using NMDA and AMPA antagonists in animal and human studies of SE investigations.
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Affiliation(s)
- Tzu-Hsin Huang
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70142, Taiwan
- Zhengxin Neurology & Rehabilitation Center, Tainan 70459, Taiwan
| | - Ming-Chi Lai
- Department of Pediatrics, Chi-Mei Medical Center, Tainan 71004, Taiwan
| | - Yu-Shiue Chen
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70142, Taiwan
| | - Chin-Wei Huang
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70142, Taiwan
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5
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Balena T, Lillis K, Rahmati N, Bahari F, Dzhala V, Berdichevsky E, Staley K. A dynamic balance between neuronal death and clearance after acute brain injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.14.528332. [PMID: 36824708 PMCID: PMC9948967 DOI: 10.1101/2023.02.14.528332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
After acute brain injury, neuronal apoptosis may overwhelm the capacity for microglial phagocytosis, creating a queue of dying neurons awaiting clearance. The size of this queue should be equally sensitive to changes in neuronal death and the rate of phagocytosis. Using rodent organotypic hippocampal slice cultures as a model of acute perinatal brain injury, serial imaging demonstrated that the capacity for microglial phagocytosis of dying neurons was overwhelmed for two weeks. Altering phagocytosis rates, e.g. by changing the number of microglia, dramatically changed the number of visibly dying neurons. Similar effects were generated when the visibility of dying neurons was altered by changing the membrane permeability for vital stains. Canonically neuroprotective interventions such as seizure blockade and neurotoxic maneuvers such as perinatal ethanol exposure were mediated by effects on microglial activity and the membrane permeability of apoptotic neurons, and had either no or opposing effects on healthy surviving neurons. Significance After acute brain injury, microglial phagocytosis is overwhelmed by the number of dying cells. Under these conditions, the assumptions on which assays for neuroprotective and neurotoxic effects are based are no longer valid. Thus longitudinal assays of healthy cells, such as assessment of the fluorescence emission of transgenically-expressed proteins, provide more accurate estimates of cell death than do single-time-point anatomical or biochemical assays. More accurate estimates of death rates will increase the translatability of preclinical studies of neuroprotection and neurotoxicity.
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6
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The Role of MEF2 Transcription Factor Family in Neuronal Survival and Degeneration. Int J Mol Sci 2023; 24:ijms24043120. [PMID: 36834528 PMCID: PMC9963821 DOI: 10.3390/ijms24043120] [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: 12/30/2022] [Revised: 01/15/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
The family of myocyte enhancer factor 2 (MEF2) transcription factors comprises four highly conserved members that play an important role in the nervous system. They appear in precisely defined time frames in the developing brain to turn on and turn off genes affecting growth, pruning and survival of neurons. MEF2s are known to dictate neuronal development, synaptic plasticity and restrict the number of synapses in the hippocampus, thus affecting learning and memory formation. In primary neurons, negative regulation of MEF2 activity by external stimuli or stress conditions is known to induce apoptosis, albeit the pro or antiapoptotic action of MEF2 depends on the neuronal maturation stage. By contrast, enhancement of MEF2 transcriptional activity protects neurons from apoptotic death both in vitro and in preclinical models of neurodegenerative diseases. A growing body of evidence places this transcription factor in the center of many neuropathologies associated with age-dependent neuronal dysfunctions or gradual but irreversible neuron loss. In this work, we discuss how the altered function of MEF2s during development and in adulthood affecting neuronal survival may be linked to neuropsychiatric disorders.
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7
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Muscarinic Receptors in Developmental Axonal Competition at the Neuromuscular Junction. Mol Neurobiol 2023; 60:1580-1593. [PMID: 36526930 PMCID: PMC9899176 DOI: 10.1007/s12035-022-03154-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022]
Abstract
In recent years, we have studied by immunohistochemistry, intracellular recording, and western blotting the role of the muscarinic acetylcholine receptors (mAChRs; M1, M2, and M4 subtypes) in the mammalian neuromuscular junction (NMJ) during development and in the adult. Here, we evaluate our published data to emphasize the mAChRs' relevance in developmental synaptic elimination and their crosstalk with other metabotropic receptors, downstream kinases, and voltage-gated calcium channels (VGCCs). The presence of mAChRs in the presynaptic membrane of motor nerve terminals allows an autocrine mechanism in which the secreted acetylcholine influences the cell itself in feedback. mAChR subtypes are coupled to different downstream pathways, so their feedback can move in a broad range between positive and negative. Moreover, mAChRs allow direct activity-dependent interaction through ACh release between the multiple competing axons during development. Additional regulation from pre- and postsynaptic sites (including neurotrophic retrograde control), the agonistic and antagonistic contributions of adenosine receptors (AR; A1 and A2A), and the tropomyosin-related kinase B receptor (TrkB) cooperate with mAChRs in the axonal competitive interactions which lead to supernumerary synapse elimination that achieves the optimized monoinnervation of musculoskeletal cells. The metabotropic receptor-driven balance between downstream PKA and PKC activities, coupled to developmentally regulated VGCC, explains much of how nerve terminals with different activities finally progress to their withdrawal or strengthening.
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8
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Sivakumar S, Ghasemi M, Schachter SC. Targeting NMDA Receptor Complex in Management of Epilepsy. Pharmaceuticals (Basel) 2022; 15:ph15101297. [PMID: 36297409 PMCID: PMC9609646 DOI: 10.3390/ph15101297] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 10/17/2022] [Accepted: 10/20/2022] [Indexed: 11/05/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs) are widely distributed in the central nervous system (CNS) and play critical roles in neuronal excitability in the CNS. Both clinical and preclinical studies have revealed that the abnormal expression or function of these receptors can underlie the pathophysiology of seizure disorders and epilepsy. Accordingly, NMDAR modulators have been shown to exert anticonvulsive effects in various preclinical models of seizures, as well as in patients with epilepsy. In this review, we provide an update on the pathologic role of NMDARs in epilepsy and an overview of the NMDAR antagonists that have been evaluated as anticonvulsive agents in clinical studies, as well as in preclinical seizure models.
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Affiliation(s)
- Shravan Sivakumar
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Mehdi Ghasemi
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
- Correspondence: (M.G.); (S.C.S.)
| | - Steven C. Schachter
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
- Harvard Medical School, Boston, MA 02114, USA
- Consortia for Improving Medicine with Innovation & Technology (CIMIT), Boston, MA 02114, USA
- Correspondence: (M.G.); (S.C.S.)
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9
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Fields C, Glazebrook JF, Levin M. Neurons as hierarchies of quantum reference frames. Biosystems 2022; 219:104714. [PMID: 35671840 DOI: 10.1016/j.biosystems.2022.104714] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 05/28/2022] [Accepted: 05/28/2022] [Indexed: 11/19/2022]
Abstract
Conceptual and mathematical models of neurons have lagged behind empirical understanding for decades. Here we extend previous work in modeling biological systems with fully scale-independent quantum information-theoretic tools to develop a uniform, scalable representation of synapses, dendritic and axonal processes, neurons, and local networks of neurons. In this representation, hierarchies of quantum reference frames act as hierarchical active-inference systems. The resulting model enables specific predictions of correlations between synaptic activity, dendritic remodeling, and trophic reward. We summarize how the model may be generalized to nonneural cells and tissues in developmental and regenerative contexts.
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Affiliation(s)
- Chris Fields
- 23 Rue des Lavandières, 11160 Caunes Minervois, France.
| | - James F Glazebrook
- Department of Mathematics and Computer Science, Eastern Illinois University, Charleston, IL 61920, USA; Adjunct Faculty, Department of Mathematics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
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10
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Pandey S, Mudgal J. A Review on the Role of Endogenous Neurotrophins and Schwann Cells in Axonal Regeneration. J Neuroimmune Pharmacol 2022; 17:398-408. [PMID: 34843075 PMCID: PMC9810669 DOI: 10.1007/s11481-021-10034-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 11/13/2021] [Indexed: 01/13/2023]
Abstract
Injury to the peripheral nerve is traditionally referred to acquired nerve injury as they are the result of physical trauma due to laceration, stretch, crush and compression of nerves. However, peripheral nerve injury may not be completely limited to acquired physical trauma. Peripheral nerve injury equally implies clinical conditions like Guillain-Barré syndrome (GBS), Carpal tunnel syndrome, rheumatoid arthritis and diabetes. Physical trauma is commonly mono-neuropathic as it engages a single nerve and produces focal damage, while in the context of pathological conditions the damage is divergent involving a group of the nerve causing polyneuropathy. Damage to the peripheral nerve can cause a diverse range of manifestations from sensory impairment to loss of function with unpredictable recovery patterns. Presently no treatment option provides complete or functional recovery in nerve injury, as nerve cells are highly differentiated and inert to regeneration. However, the regenerative phenotypes in Schwann cells get expressed when a signalling cascade is triggered by neurotrophins. Neurotrophins are one of the promising biomolecules that are released naturally post-injury with the potential to exhibit better functional recovery. Pharmacological intervention modulating the expression of these neurotrophins such as brain-derived neurotrophic factor (BDNF) and pituitary adenylyl cyclase-activating peptide (PACAP) can prove to be a significant treatment option as endogenous compounds which may have remarkable innate advantage showing maximum 'biological relevance'.
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Affiliation(s)
- Samyak Pandey
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India, 576104
| | - Jayesh Mudgal
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India, 576104.
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Alshamrani AA, Franklin JL. Membrane Depolarization Inhibits BIM EL Upregulation but Prevents Neuronal Apoptosis Primarily by Increasing Cellular GSH Levels. Mol Neurobiol 2021; 58:2284-2296. [PMID: 33417218 DOI: 10.1007/s12035-020-02234-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 11/25/2020] [Indexed: 11/24/2022]
Abstract
Sympathetic neurons deprived of nerve growth factor (NGF) die by apoptosis. Chronic depolarization with elevated concentrations of extracellular potassium ([K+]E) supports long-term survival of these and other types of neurons in culture. While depolarization has long been used to support neuronal cultures, little is known about the mechanism. We explored how chronic depolarization of NGF-deprived mouse sympathetic neurons in culture blocks apoptotic death. First, we determined the effects of elevated [K+]E on proapoptotic BH3-only proteins reported to be upregulated in sympathetic neurons after NGF withdrawal. Upregulation of BIMEL was blocked by depolarization while upregulation of PUMA was not. BMF levels did not increase after NGF withdrawal, and elevated [K+]E had no effect on its expression. dp5/HRK was not detectable. A large increase in production of mitochondria-derived reactive species (RS), including reactive oxygen species (ROS), occurs in NGF-deprived sympathetic neurons. Suppressing these RS prevents cytochrome c release from mitochondria and apoptosis. The addition of high [K+]E to cultures rapidly blocked increased RS and cytochrome c release. Elevated [K+]E caused an increase of the cellular antioxidant glutathione (GSH). Preventing this increase prevented the elevated [K+]E from blocking cytochrome c release and death. While suppression of BIMEL upregulation by elevated [K+]E may contribute to high [K+]E pro-survival effects, we conclude that elevated [K+]E prevents apoptotic death of NGF-deprived sympathetic neurons primarily via an antioxidant mechanism.
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Affiliation(s)
- Ali A Alshamrani
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, 30602, USA.,Department of Pharmacology and Toxicology, King Saud University, Riyadh, 11451, Saudi Arabia
| | - James L Franklin
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, 30602, USA.
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Meng L, Yan D. NLR-1/CASPR Anchors F-Actin to Promote Gap Junction Formation. Dev Cell 2020; 55:574-587.e3. [PMID: 33238150 DOI: 10.1016/j.devcel.2020.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 08/05/2020] [Accepted: 10/28/2020] [Indexed: 12/31/2022]
Abstract
Gap junctions are present in most tissues and play essential roles in various biological processes. However, we know surprisingly little about the molecular mechanisms underlying gap junction formation. Here, we uncover the essential role of a conserved EGF- and laminin-G-domain-containing protein nlr-1/CASPR in the regulation of gap junction formation in multiple tissues across different developmental stages in C. elegans. NLR-1 is located in the gap junction perinexus, a region adjacent to but not overlapping with gap junctions, and forms puncta before the clusters of gap junction channels appear on the membrane. We show that NLR-1 can directly bind to actin to recruit F-actin networks at the gap junction formation plaque, and the formation of F-actin patches plays a critical role in the assembly of gap junction channels. Our findings demonstrate that nlr-1/CASPR acts as an early stage signal for gap junction formation through anchoring of F-actin networks.
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Affiliation(s)
- Lingfeng Meng
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Dong Yan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology, Regeneration Next, and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC 27710, USA.
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13
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Cognitive and Social Rehabilitation in Schizophrenia-From Neurophysiology to Neuromodulation. Pilot Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17114034. [PMID: 32517043 PMCID: PMC7312635 DOI: 10.3390/ijerph17114034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/02/2020] [Accepted: 06/03/2020] [Indexed: 11/18/2022]
Abstract
The aim of this pilot study was to analyse the influence of Galvanic Skin Response (GSR) Biofeedback training in a group of 18 men with schizophrenia at the remission stage. The results were verified according to: Positive and Negative Syndrome Scale (PANSS), Acceptance of Illness Scale (AIS), Self-efficacy Scale (GSES), Beck Cognitive Insight Scale (BCIS) scales, Colour Trial Test (CTT-1, CTT-2), d2 psychological tests, Quantitative Electroencephalogram (QEEG) Biofeedback, auditory event-related potentials (ERPs), and serum levels of brain-derived neurotrophic factor (BDNF). The results were compared in the same patients after 3 months. Statistically significant changes were noted in results for the variables on the PANSS scale. For the BDNF variable, a statistically significant increase occurred, indicating that GSR Biofeedback training may influence serum levels of the neurotrophic factor. Statistically significant changes were noted in results for the variables on the BCIS, AIS, and GSES indicating an improvement in the cognitive and social functioning. Changes were noted for results for theta/beta and theta/Sensory Motor Rhythm (SMR) ratios, which indicate an improvement in concentration and attention. Changes were noted for the N1 wave amplitude in the frontal brain region (F-z), and for the P2 wave latency in the central brain region (C-z), which indicates an improvement in the initial perceptual analysis. The use of GSR Biofeedback in a group of patients with schizophrenia gives interesting results, but requires further in-depth research.
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Chan MTV, Hedrick TL, Egan TD, García PS, Koch S, Purdon PL, Ramsay MA, Miller TE, McEvoy MD, Gan TJ. American Society for Enhanced Recovery and Perioperative Quality Initiative Joint Consensus Statement on the Role of Neuromonitoring in Perioperative Outcomes. Anesth Analg 2020; 130:1278-1291. [DOI: 10.1213/ane.0000000000004502] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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15
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Gbx1 and Gbx2 Are Essential for Normal Patterning and Development of Interneurons and Motor Neurons in the Embryonic Spinal Cord. J Dev Biol 2020; 8:jdb8020009. [PMID: 32244588 PMCID: PMC7345146 DOI: 10.3390/jdb8020009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/01/2020] [Accepted: 03/26/2020] [Indexed: 12/17/2022] Open
Abstract
The molecular mechanisms regulating neurogenesis involve the control of gene expression by transcription factors. Gbx1 and Gbx2, two members of the Gbx family of homeodomain-containing transcription factors, are known for their essential roles in central nervous system development. The expression domains of mouse Gbx1 and Gbx2 include regions of the forebrain, anterior hindbrain, and spinal cord. In the spinal cord, Gbx1 and Gbx2 are expressed in PAX2+ interneurons of the dorsal horn and ventral motor neuron progenitors. Based on their shared domains of expression and instances of overlap, we investigated the functional relationship between Gbx family members in the developing spinal cord using Gbx1−/−, Gbx2−/−, and Gbx1−/−/Gbx2−/− embryos. In situ hybridization analyses of embryonic spinal cords show upregulation of Gbx2 expression in Gbx1−/− embryos and upregulation of Gbx1 expression in Gbx2−/− embryos. Additionally, our data demonstrate that Gbx genes regulate development of a subset of PAX2+ dorsal inhibitory interneurons. While we observe no difference in overall proliferative status of the developing ependymal layer, expansion of proliferative cells into the anatomically defined mantle zone occurs in Gbx mutants. Lastly, our data shows a marked increase in apoptotic cell death in the ventral spinal cord of Gbx mutants during mid-embryonic stages. While our studies reveal that both members of the Gbx gene family are involved in development of subsets of PAX2+ dorsal interneurons and survival of ventral motor neurons, Gbx1 and Gbx2 are not sufficient to genetically compensate for the loss of one another. Thus, our studies provide novel insight to the relationship harbored between Gbx1 and Gbx2 in spinal cord development.
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Duan ZRS, Che A, Chu P, Modol L, Bollmann Y, Babij R, Fetcho RN, Otsuka T, Fuccillo MV, Liston C, Pisapia DJ, Cossart R, De Marco García NV. GABAergic Restriction of Network Dynamics Regulates Interneuron Survival in the Developing Cortex. Neuron 2019; 105:75-92.e5. [PMID: 31780329 DOI: 10.1016/j.neuron.2019.10.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 07/23/2019] [Accepted: 10/01/2019] [Indexed: 12/15/2022]
Abstract
During neonatal development, sensory cortices generate spontaneous activity patterns shaped by both sensory experience and intrinsic influences. How these patterns contribute to the assembly of neuronal circuits is not clearly understood. Using longitudinal in vivo calcium imaging in un-anesthetized mouse pups, we show that spatially segregated functional assemblies composed of interneurons and pyramidal cells are prominent in the somatosensory cortex by postnatal day (P) 7. Both reduction of GABA release and synaptic inputs onto pyramidal cells erode the emergence of functional topography, leading to increased network synchrony. This aberrant pattern effectively blocks interneuron apoptosis, causing increased survival of parvalbumin and somatostatin interneurons. Furthermore, the effect of GABA on apoptosis is mediated by inputs from medial ganglionic eminence (MGE)-derived but not caudal ganglionic eminence (CGE)-derived interneurons. These findings indicate that immature MGE interneurons are fundamental for shaping GABA-driven activity patterns that balance the number of interneurons integrating into maturing cortical networks.
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Affiliation(s)
- Zhe Ran S Duan
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA; Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10021, USA
| | - Alicia Che
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Philip Chu
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Laura Modol
- Aix Marseille University, INSERM, INMED, Turing Center for Living Systems, Marseille, France
| | - Yannick Bollmann
- Aix Marseille University, INSERM, INMED, Turing Center for Living Systems, Marseille, France
| | - Rachel Babij
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA; Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10021, USA
| | - Robert N Fetcho
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA; Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10021, USA
| | - Takumi Otsuka
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - Marc V Fuccillo
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Conor Liston
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA
| | - David J Pisapia
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Rosa Cossart
- Aix Marseille University, INSERM, INMED, Turing Center for Living Systems, Marseille, France
| | - Natalia V De Marco García
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10021, USA.
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17
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Brown JM, Bland R, Jonsson E, Greenshaw AJ. The Standardization of Diagnostic Criteria for Fetal Alcohol Spectrum Disorder (FASD): Implications for Research, Clinical Practice and Population Health. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2019; 64:169-176. [PMID: 29788774 PMCID: PMC6405816 DOI: 10.1177/0706743718777398] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Fetal Alcohol Spectrum Disorder (FASD) is a preventable disorder caused by maternal alcohol consumption and marked by a range of physical and mental disabilities. Although recognized by the scientific and medical community as a clinical disorder, no internationally standardized diagnostic tool yet exists for FASD. METHODS AND RESULTS This review seeks to analyse the discrepancies in existing diagnostic tools for FASD, and the repercussions these differences have on research, public health, and government policy. CONCLUSIONS Disagreement on the adoption of a standardised tool is reflective of existing gaps in research on the conditions and factors that influence fetal vulnerability to damage from exposure. This discordance has led to variability in research findings, inconsistencies in government messaging, and misdiagnoses or missed diagnoses. The objective measurement of the timing and level of prenatal alcohol exposure is key to bridging these gaps; however, there is conflicting or limited evidence to support the use of existing measures.
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Affiliation(s)
- Jasmine M. Brown
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Roger Bland
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Egon Jonsson
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
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18
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Fernandez A, Santi A, Torres Aleman I. Insulin Peptides as Mediators of the Impact of Life Style in Alzheimer's disease. Brain Plast 2018; 4:3-15. [PMID: 30564544 PMCID: PMC6297900 DOI: 10.3233/bpl-180071] [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] [Accepted: 05/11/2018] [Indexed: 01/15/2023] Open
Abstract
The search for the cause of Alzheimer's disease (AD), that affects millions of people worldwide, is currently one of the most important scientific endeavors from a clinical perspective. There are so many mechanisms proposed, and so disparate changes observed, that it is becoming a challenging task to provide a comprehensive view of possible pathogenic processes in AD. Tauopathy (intracellular neurofibrillary tangles) and amyloidosis (extracellular amyloid plaques) are the anatomical hallmarks of the disease, and the formation of these proteinaceous aggregates in specific brain areas is widely held as the ultimate pathogenic mechanism. However, the triggers of this dysproteostasis process remain unknown. Further, neurofibrillary tangles and plaques may only constitute the last stages of a process of still uncertain origin. Thus, without an established knowledge of its etiology, and no cure in the horizon, prevention - or merely delaying its development, has become a last-resort goal in AD research. As with other success stories in preventive medicine, epidemiological studies have provided basic knowledge of risk factors in AD that may contribute to understand its etiology. Disregarding old age, gender, and ApoE4 genotype as non preventable risk factors, there are diverse life-style traits - many of them closely related to cardiovascular health, that have been associated to AD risk. Most prominent among them are diet, physical and mental activity, exposure to stress, and sleep/wake patterns. We argue that all these life-style factors engage insulinergic pathways that affect brain function, providing a potentially unifying thread for life-style and AD risk. Although further studies are needed to firmly establish a link between faulty insulinergic function and AD, we herein summarize the evidence that this link should be thoroughly considered.
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Affiliation(s)
| | - A. Santi
- Cajal Institute and Ciberned, Madrid, Spain
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19
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Thornton MA, Mehta MD, Morad TT, Ingraham KL, Khankan RR, Griffis KG, Yeung AK, Zhong H, Roy RR, Edgerton VR, Phelps PE. Evidence of axon connectivity across a spinal cord transection in rats treated with epidural stimulation and motor training combined with olfactory ensheathing cell transplantation. Exp Neurol 2018; 309:119-133. [PMID: 30056160 PMCID: PMC6365019 DOI: 10.1016/j.expneurol.2018.07.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/18/2018] [Accepted: 07/24/2018] [Indexed: 12/16/2022]
Abstract
Olfactory ensheathing cells (OECs) are unique glia that support axon outgrowth in the olfactory system, and when used as cellular therapy after spinal cord injury, improve recovery and axon regeneration. Here we assessed the effects of combining OEC transplantation with another promising therapy, epidural electrical stimulation during a rehabilitative motor task. Sprague-Dawley rats received a mid-thoracic transection and transplantation of OECs or fibroblasts (FBs) followed by lumbar stimulation while climbing an inclined grid. We injected pseudorabies virus (PRV) into hindlimb muscles 7 months post-injury to assess connectivity across the transection. Analyses showed that the number of serotonergic (5-HT) axons that crossed the rostral scar border and the area of neurofilament-positive axons in the injury site were both greater in OEC- than FB-treated rats. We detected PRV-labeled cells rostral to the transection and remarkable evidence of 5-HT and PRV axons crossing the injury site in 1 OEC- and 1 FB-treated rat. The axons that crossed suggested either axon regeneration (OEC) or small areas of probable tissue sparing (FB). Most PRV-labeled thoracic neurons were detected in laminae VII or X, and ~25% expressed Chx10, a marker for V2a interneurons. These findings suggest potential regeneration or sparing of circuits that connect thoracic interneurons to lumbar somatic motor neurons. Despite evidence of axonal connectivity, no behavioral changes were detected in this small-scale study. Together these data suggest that when supplemented with epidural stimulation and climbing, OEC transplantation can increase axonal growth across the injury site and may promote recovery of propriospinal circuitry.
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Affiliation(s)
- Michael A Thornton
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, United States
| | - Manan D Mehta
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, United States
| | - Tyler T Morad
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, United States
| | - Kaitlin L Ingraham
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, United States; Molecular, Cellular and Integrative Physiology, Interdepartmental Ph.D. Program, UCLA, Los Angeles, CA 90095, United States
| | - Rana R Khankan
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, United States; Molecular, Cellular and Integrative Physiology, Interdepartmental Ph.D. Program, UCLA, Los Angeles, CA 90095, United States
| | - Khris G Griffis
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, United States; Molecular, Cellular and Integrative Physiology, Interdepartmental Ph.D. Program, UCLA, Los Angeles, CA 90095, United States
| | - Anthony K Yeung
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, United States
| | - Hui Zhong
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, United States
| | - Roland R Roy
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, United States; Brain Research Institute, UCLA, Los Angeles, CA 90095, United States
| | - V Reggie Edgerton
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, United States; Molecular, Cellular and Integrative Physiology, Interdepartmental Ph.D. Program, UCLA, Los Angeles, CA 90095, United States; Brain Research Institute, UCLA, Los Angeles, CA 90095, United States
| | - Patricia E Phelps
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, United States; Molecular, Cellular and Integrative Physiology, Interdepartmental Ph.D. Program, UCLA, Los Angeles, CA 90095, United States; Brain Research Institute, UCLA, Los Angeles, CA 90095, United States.
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20
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In vivo two-photon imaging of the embryonic cortex reveals spontaneous ketamine-sensitive calcium activity. Sci Rep 2018; 8:16059. [PMID: 30375447 PMCID: PMC6207746 DOI: 10.1038/s41598-018-34410-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 10/10/2018] [Indexed: 01/18/2023] Open
Abstract
Prior to sensory experience spontaneous activity appears to play a fundamental role in the correct formation of prominent functional features of different cortical regions. The use of anaesthesia during pregnancy such as ketamine is largely considered to negatively affect neuronal development by interfering with synaptic transmission. Interestingly, the characteristics of spontaneous activity as well as the acute functional effects of maternal anaesthesia remain largely untested in the embryonic cortex in vivo. In the present work, we performed in vivo imaging of spontaneous calcium activity and cell motility in the marginal zone of the cortex of E14-15 embryos connected to the mother. We made use of a preparation where the blood circulation from the mother through the umbilical cord is preserved and fluctuations in intracellular calcium in the embryonic frontal cortex are acquired using two-photon imaging. We found that spontaneous transients were either sporadic or correlated in clusters of neuronal ensembles at this age. These events were not sensitive to maternal isoflurane anaesthesia but were strongly inhibited by acute in situ or maternal application of low concentration of the anaesthetic ketamine (a non-competitive antagonist of NMDA receptors). Moreover, simultaneous imaging of cell motility revealed a correlated strong sensitivity to ketamine. These results show that anaesthetic compounds can differ significantly in their impact on spontaneous early cortical activity as well as motility of cells in the marginal zone. The effects found in this study may be relevant in the etiology of heightened vulnerability to cerebral dysfunction associated with the use of ketamine during pregnancy.
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21
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Sachana M, Rolaki A, Bal-Price A. Development of the Adverse Outcome Pathway (AOP): Chronic binding of antagonist to N-methyl-d-aspartate receptors (NMDARs) during brain development induces impairment of learning and memory abilities of children. Toxicol Appl Pharmacol 2018; 354:153-175. [PMID: 29524501 PMCID: PMC6095943 DOI: 10.1016/j.taap.2018.02.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/26/2018] [Accepted: 02/28/2018] [Indexed: 01/06/2023]
Abstract
The Adverse Outcome Pathways (AOPs) are designed to provide mechanistic understanding of complex biological systems and pathways of toxicity that result in adverse outcomes (AOs) relevant to regulatory endpoints. AOP concept captures in a structured way the causal relationships resulting from initial chemical interaction with biological target(s) (molecular initiating event) to an AO manifested in individual organisms and/or populations through a sequential series of key events (KEs), which are cellular, anatomical and/or functional changes in biological processes. An AOP provides the mechanistic detail required to support chemical safety assessment, the development of alternative methods and the implementation of an integrated testing strategy. An example of the AOP relevant to developmental neurotoxicity (DNT) is described here following the requirements of information defined by the OECD Users' Handbook Supplement to the Guidance Document for developing and assessing AOPs. In this AOP, the binding of an antagonist to glutamate receptor N-methyl-d-aspartate (NMDAR) receptor is defined as MIE. This MIE triggers a cascade of cellular KEs including reduction of intracellular calcium levels, reduction of brain derived neurotrophic factor release, neuronal cell death, decreased glutamate presynaptic release and aberrant dendritic morphology. At organ level, the above mentioned KEs lead to decreased synaptogenesis and decreased neuronal network formation and function causing learning and memory deficit at organism level, which is defined as the AO. There are in vitro, in vivo and epidemiological data that support the described KEs and their causative relationships rendering this AOP relevant to DNT evaluation in the context of regulatory purposes.
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Affiliation(s)
| | | | - Anna Bal-Price
- European Commission, Joint Research Centre, Ispra, Italy.
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22
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Khazipov R, Milh M. Early patterns of activity in the developing cortex: Focus on the sensorimotor system. Semin Cell Dev Biol 2018; 76:120-129. [DOI: 10.1016/j.semcdb.2017.09.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 02/08/2023]
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23
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Lebedeva J, Zakharov A, Ogievetsky E, Minlebaeva A, Kurbanov R, Gerasimova E, Sitdikova G, Khazipov R. Inhibition of Cortical Activity and Apoptosis Caused by Ethanol in Neonatal Rats In Vivo. Cereb Cortex 2018; 27:1068-1082. [PMID: 26646511 DOI: 10.1093/cercor/bhv293] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Alcohol consumption during pregnancy causes fetal alcohol spectrum disorder, which includes neuroapoptosis and neurobehavioral deficits. The neuroapoptotic effects of alcohol have been hypothesized to involve suppression of brain activity. However, in vitro studies suggest that ethanol acts as a potent stimulant of cortical activity. We explored the effects of alcohol (1-6 g/kg) on electrical activity in the rat somatosensory cortex in vivo at postnatal days P1-23 and compared them with its apoptotic actions. At P4-7, when the peak of alcohol-induced apoptosis was observed, alcohol strongly suppressed spontaneous gamma and spindle-bursts and almost completely silenced neurons in a dose-dependent manner. The dose-dependence of suppression of neuronal activity strongly correlated with the alcohol-induced neuroapoptosis. Alcohol also profoundly inhibited sensory-evoked bursts and suppressed motor activity, a physiological trigger of cortical activity bursts in newborns. The suppressive effects of ethanol on neuronal activity waned during the second and third postnatal weeks, when instead of silencing the cortex, alcohol evoked delta-wave electrographic activity. Thus, the effects of alcohol on brain activity are strongly age-dependent, and during the first postnatal week alcohol profoundly inhibits brain activity. Our findings suggest that the adverse effects of alcohol in the developing brain involve suppression of neuronal activity.
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Affiliation(s)
- Julia Lebedeva
- Laboratory of Neurobiology, Kazan Federal University, Kazan, 420000, Russia.,INMED, INSERM U-901, Marseille, 13273, France.,Aix-Marseille University, Marseille, 13273, France
| | - Andrei Zakharov
- Laboratory of Neurobiology, Kazan Federal University, Kazan, 420000, Russia.,Department of Physiology, Kazan State Medical University, Kazan, 420012, Russia
| | - Elena Ogievetsky
- INMED, INSERM U-901, Marseille, 13273, France.,Aix-Marseille University, Marseille, 13273, France
| | - Alina Minlebaeva
- INMED, INSERM U-901, Marseille, 13273, France.,Aix-Marseille University, Marseille, 13273, France
| | - Rustem Kurbanov
- Laboratory of Neurobiology, Kazan Federal University, Kazan, 420000, Russia
| | - Elena Gerasimova
- Laboratory of Neurobiology, Kazan Federal University, Kazan, 420000, Russia
| | - Guzel Sitdikova
- Laboratory of Neurobiology, Kazan Federal University, Kazan, 420000, Russia
| | - Roustem Khazipov
- Laboratory of Neurobiology, Kazan Federal University, Kazan, 420000, Russia.,INMED, INSERM U-901, Marseille, 13273, France.,Aix-Marseille University, Marseille, 13273, France
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24
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Lotfullina N, Khazipov R. Ethanol and the Developing Brain: Inhibition of Neuronal Activity and Neuroapoptosis. Neuroscientist 2017; 24:130-141. [PMID: 28580823 DOI: 10.1177/1073858417712667] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Ethanol induces massive neuroapoptosis in the developing brain. One of the main hypotheses that has been put forward to explain the deleterious actions of ethanol in the immature brain involves an inhibition of neuronal activity. Here, we review recent evidence for this hypothesis obtained in the somatosensory cortex and hippocampus of neonatal rodents. In both structures, ethanol strongly inhibits brain activity. At the doses inducing massive neuroapoptosis, ethanol completely suppresses the early activity patterns of spindle-bursts and gamma oscillations in the neocortex and the early sharp-waves in the hippocampus. The inhibitory effects of ethanol decrease with age and in adult animals, ethanol only mildly depresses neuronal firing and induces delta-wave activity. Suppression of cortical activity in neonatal animals likely involves inhibition of the myoclonic twitches, an important physiological trigger for the early activity bursts, and inhibition of the thalamocortical and intracortical circuits through a potentiation of GABAergic transmission and an inhibition of N-methyl-d-aspartate (NMDA) receptors, that is in keeping with the neuroapoptotic effects of other agents acting on GABA and NMDA receptors. These findings provide support for the hypothesis that the ethanol-induced inhibition of cortical activity is an important pathophysiological mechanism underlying massive neuroapoptosis induced by ethanol in the developing brain.
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Affiliation(s)
- Nailya Lotfullina
- 1 INMED-INSERM, Aix-Marseille University, Marseille, France.,2 Laboratory of Neurobiology, Kazan Federal University, Kazan, Russia
| | - Roustem Khazipov
- 1 INMED-INSERM, Aix-Marseille University, Marseille, France.,2 Laboratory of Neurobiology, Kazan Federal University, Kazan, Russia
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25
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Tomàs J, Garcia N, Lanuza MA, Santafé MM, Tomàs M, Nadal L, Hurtado E, Simó A, Cilleros V. Presynaptic Membrane Receptors Modulate ACh Release, Axonal Competition and Synapse Elimination during Neuromuscular Junction Development. Front Mol Neurosci 2017; 10:132. [PMID: 28559796 PMCID: PMC5432534 DOI: 10.3389/fnmol.2017.00132] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/20/2017] [Indexed: 12/17/2022] Open
Abstract
During the histogenesis of the nervous system a lush production of neurons, which establish an excessive number of synapses, is followed by a drop in both neurons and synaptic contacts as maturation proceeds. Hebbian competition between axons with different activities leads to the loss of roughly half of the neurons initially produced so connectivity is refined and specificity gained. The skeletal muscle fibers in the newborn neuromuscular junction (NMJ) are polyinnervated but by the end of the competition, 2 weeks later, the NMJ are innervated by only one axon. This peripheral synapse has long been used as a convenient model for synapse development. In the last few years, we have studied transmitter release and the local involvement of the presynaptic muscarinic acetylcholine autoreceptors (mAChR), adenosine autoreceptors (AR) and trophic factor receptors (TFR, for neurotrophins and trophic cytokines) during the development of NMJ and in the adult. This review article brings together previously published data and proposes a molecular background for developmental axonal competition and loss. At the end of the first week postnatal, these receptors modulate transmitter release in the various nerve terminals on polyinnervated NMJ and contribute to axonal competition and synapse elimination.
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Affiliation(s)
- Josep Tomàs
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Neus Garcia
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Maria A Lanuza
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Manel M Santafé
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Marta Tomàs
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Laura Nadal
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Erica Hurtado
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Anna Simó
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Víctor Cilleros
- Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
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26
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Ascenzi M, Bony G. The building of the neocortex with non-hyperpolarizing neurotransmitters. Dev Neurobiol 2017; 77:1023-1037. [PMID: 28276653 DOI: 10.1002/dneu.22495] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 02/16/2017] [Accepted: 02/28/2017] [Indexed: 12/12/2022]
Abstract
The development of the neocortex requires the synergic action of several secreted molecules to achieve the right amount of proliferation, differentiation, and migration of neural cells. Neurons are well known to release neurotransmitters (NTs) in adult and a growing body of evidences describes the presence of NTs already in the embryonic brain, long before the generation of synapses. NTs are classified as inhibitory or excitatory based on the physiological responses of the target neuron. However, this view is challenged by the fact that glycine and GABA NTs are excitatory during development. Many reviews have described the role of nonhyperpolarizing GABA at this stage. Nevertheless, a global consideration of the inhibitory neurotransmitters and their downstream signaling during the embryonic cortical development is still needed. For example, taurine, the most abundant neurotransmitter during development is poorly studied regarding its role during cortical development. In the light of recent discoveries, we will discuss the functions of glycine, GABA, and taurine during embryonic cortical development with an emphasis on their downstream signaling. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1023-1037, 2017.
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Affiliation(s)
| | - Guillaume Bony
- INSERM U1215, NeuroCentre Magendie, Bordeaux, France.,Université de Bordeaux, NeuroCentre Magendie, Bordeaux, France
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27
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Lebedeva YA, Zakharova AV, Sitdikova GF, Zefirov AL, Khazipov RN. Ketamine-Midazolam Anesthesia Induces Total Inhibition of Cortical Activity in the Brain of Newborn Rats. Bull Exp Biol Med 2016; 161:15-9. [PMID: 27270941 DOI: 10.1007/s10517-016-3334-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Indexed: 11/25/2022]
Abstract
The effects of general anesthetics ketamine and midazolam, the drugs that cause neuroapoptosis at the early stages of CNS development, on electrical activity of the somatosensory cortex in newborn rats were studied using extracellular recording of local field potentials and action potentials of cortical neurons. Combined administration of ketamine (40 mg/kg) and midazolam (9 mg/kg) induced surgical coma and almost completely suppressed early oscillatory patterns and neuronal firing. These effects persisted over 3 h after injection of the anesthetics. We concluded that general anesthesia induced by combined administration of ketamine and midazolam profoundly suppressed cortical activity in newborn rats, which can trigger neuroapoptosis in the developing brain.
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Affiliation(s)
- Yu A Lebedeva
- Kazan (Volga Region) Federal University, Kazan, Russia.,Mediterranean Institute of Neurobiology (INMED), Marseille, France
| | - A V Zakharova
- Kazan (Volga Region) Federal University, Kazan, Russia.,Kazan State Medical University, Ministry of Health of the Russian Federation, Kazan, Tatarstan Republic, Russia
| | - G F Sitdikova
- Kazan (Volga Region) Federal University, Kazan, Russia
| | - A L Zefirov
- Kazan State Medical University, Ministry of Health of the Russian Federation, Kazan, Tatarstan Republic, Russia
| | - R N Khazipov
- Kazan (Volga Region) Federal University, Kazan, Russia. .,Mediterranean Institute of Neurobiology (INMED), Marseille, France. .,Aix-Marseille University, Marseille, France.
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Chloride Co-transporter NKCC1 Inhibitor Bumetanide Enhances Neurogenesis and Behavioral Recovery in Rats After Experimental Stroke. Mol Neurobiol 2016; 54:2406-2414. [PMID: 26960329 DOI: 10.1007/s12035-016-9819-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 02/29/2016] [Indexed: 12/15/2022]
Abstract
Bumetanide, a selective Na+-K+-Cl--co-transporter inhibitor, is widely used in clinical practice as a loop diuretic. In addition, bumetanide has been reported to attenuate ischemia-induced cerebral edema and reduce neuronal injury. This study examined whether bumetanide could influence neurogenesis and behavioral recovery in rats after experimentally induced stroke. Adult male Wistar rats were randomly assigned to four groups: sham, sham treated with bumetanide, ischemia, and ischemia treated with bumetanide. Focal cerebral ischemia was induced by injection of endothelin-1. Bumetanide (0.2 mg/kg/day) was infused into the lateral ventricle with drug administration being initiated 1 week after ischemia and continued for 3 weeks. Behavioral impairment and recovery were evaluated by tapered/ledged beam-walking test on post-stroke days 28. Then, the rats were perfused for BrdU/DCX (neuroblast marker), BrdU/NeuN (neuronal marker), BrdU/GFAP (astrocyte marker), and BrdU/Iba-1 (microglia marker) immunohistochemistry. The numbers of neuroblasts in the subventricular zone (SVZ) were significantly increased after the experimentally induced stroke. Bumetanide treatment increased migration of neuroblasts in the SVZ towards the infarct area, enhanced long-term survival of newborn neurons, and improved sensorimotor recovery, but it did not exert any effects on inflammation. In conclusion, our results demonstrated that chronic bumetanide treatment enhances neurogenesis and behavioral recovery after experimentally induced stroke in rats.
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Zhang-Hooks Y, Agarwal A, Mishina M, Bergles DE. NMDA Receptors Enhance Spontaneous Activity and Promote Neuronal Survival in the Developing Cochlea. Neuron 2016; 89:337-50. [PMID: 26774161 PMCID: PMC4724245 DOI: 10.1016/j.neuron.2015.12.016] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 10/08/2015] [Accepted: 11/24/2015] [Indexed: 12/21/2022]
Abstract
Spontaneous bursts of activity in developing sensory pathways promote maturation of neurons, refinement of neuronal connections, and assembly of appropriate functional networks. In the developing auditory system, inner hair cells (IHCs) spontaneously fire Ca(2+) spikes, each of which is transformed into a mini-burst of action potentials in spiral ganglion neurons (SGNs). Here we show that NMDARs are expressed in SGN dendritic terminals and play a critical role during transmission of activity from IHCs to SGNs before hearing onset. NMDAR activation enhances glutamate-mediated Ca(2+) influx at dendritic terminals, promotes repetitive firing of individual SGNs in response to each synaptic event, and enhances coincident activity of neighboring SGNs that will eventually encode similar frequencies of sound. Loss of NMDAR signaling from SGNs reduced their survival both in vivo and in vitro, revealing that spontaneous activity in the prehearing cochlea promotes maturation of auditory circuitry through periodic activation of NMDARs in SGNs.
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Affiliation(s)
- YingXin Zhang-Hooks
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Amit Agarwal
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Masayoshi Mishina
- Brain Science Laboratory, the Research Organization of Science and Technology, Ritsumeikan University, Shiga 525-8577, Japan
| | - Dwight E Bergles
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Beaulé V, Tremblay S, Lafleur LP, Tremblay S, Lassonde M, Lepage JF, Théoret H. Cortical thickness in adults with agenesis of the corpus callosum. Neuropsychologia 2015; 77:359-65. [DOI: 10.1016/j.neuropsychologia.2015.09.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 07/23/2015] [Accepted: 09/11/2015] [Indexed: 10/23/2022]
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31
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Wang D, Ren M, Guo J, Yang G, Long X, Hu R, Shen W, Wang X, Zeng K. The inhibitory effects of Npas4 on seizures in pilocarpine-induced epileptic rats. PLoS One 2014; 9:e115801. [PMID: 25536221 PMCID: PMC4275263 DOI: 10.1371/journal.pone.0115801] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 11/26/2014] [Indexed: 01/22/2023] Open
Abstract
To explore the effects of neuronal Per-Arnt-Sim domain protein 4 (Npas4) on seizures in pilocarpine-induced epileptic rats, Npas4 expression was detected by double-label immunofluorescence, immunohistochemistry, and Western blotting in the brains of pilocarpine-induced epileptic model rats at 6 h, 24 h, 72 h, 7 d, 14 d, 30 d, and 60 d after status epilepticus. Npas4 was localized primarily in the nucleus and in the cytoplasm of neurons. The Npas4 protein levels increased in the acute phase of seizures (between 6 h and 72 h) and decreased in the chronic phases (between 7 d and 60 d) in the rat model. Npas4 expression was knocked down by specific siRNA interference. Then, the animals were treated with pilocarpine, and the effects on seizures were evaluated on the 7th day. The onset latencies of pilocarpine-induced seizures were decreased, while the seizure frequency, duration and attack rate increased in these rats. Our study indicates that Npas4 inhibits seizure attacks in pilocarpine-induced epileptic rats.
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Affiliation(s)
- Dan Wang
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, China
| | - Min Ren
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, China
| | - Jiamei Guo
- Department of Psychiatry, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Guang Yang
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, China
| | - Xianghua Long
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, China
| | - Rong Hu
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, China
| | - Wenjing Shen
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, China
| | - Xuefeng Wang
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, China
| | - Kebin Zeng
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, China
- * E-mail:
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Short T, Leslie K. ‘Known unknowns and unknown unknowns': electroencephalographic burst suppression and mortality. Br J Anaesth 2014; 113:897-9. [DOI: 10.1093/bja/aeu147] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Nimodipine enhances neurite outgrowth in dopaminergic brain slice co-cultures. Int J Dev Neurosci 2014; 40:1-11. [PMID: 25447789 DOI: 10.1016/j.ijdevneu.2014.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 10/24/2014] [Accepted: 10/26/2014] [Indexed: 11/24/2022] Open
Abstract
Calcium ions (Ca(2+)) play important roles in neuroplasticity and the regeneration of nerves. Intracellular Ca(2+) concentrations are regulated by Ca(2+) channels, among them L-type voltage-gated Ca(2+) channels, which are inhibited by dihydropyridines like nimodipine. The purpose of this study was to investigate the effect of nimodipine on neurite growth during development and regeneration. As an appropriate model to study neurite growth, we chose organotypic brain slice co-cultures of the mesocortical dopaminergic projection system, consisting of the ventral tegmental area/substantia nigra and the prefrontal cortex from neonatal rat brains. Quantification of the density of the newly built neurites in the border region (region between the two cultivated slices) of the co-cultures revealed a growth promoting effect of nimodipine at concentrations of 0.1μM and 1μM that was even more pronounced than the effect of the growth factor NGF. This beneficial effect was absent when 10μM nimodipine were applied. Toxicological tests revealed that the application of nimodipine at this higher concentration slightly induced caspase 3 activation in the cortical part of the co-cultures, but did neither affect the amount of lactate dehydrogenase release or propidium iodide uptake nor the ratio of bax/bcl-2. Furthermore, the expression levels of different genes were quantified after nimodipine treatment. The expression of Ca(2+) binding proteins, immediate early genes, glial fibrillary acidic protein, and myelin components did not change significantly after treatment, indicating that the regulation of their expression is not primarily involved in the observed nimodipine mediated neurite growth. In summary, this study revealed for the first time a neurite growth promoting effect of nimodipine in the mesocortical dopaminergic projection system that is highly dependent on the applied concentrations.
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Williams AJ, Umemori H. The best-laid plans go oft awry: synaptogenic growth factor signaling in neuropsychiatric disease. Front Synaptic Neurosci 2014; 6:4. [PMID: 24672476 PMCID: PMC3957327 DOI: 10.3389/fnsyn.2014.00004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 02/21/2014] [Indexed: 12/27/2022] Open
Abstract
Growth factors play important roles in synapse formation. Mouse models of neuropsychiatric diseases suggest that defects in synaptogenic growth factors, their receptors, and signaling pathways can lead to disordered neural development and various behavioral phenotypes, including anxiety, memory problems, and social deficits. Genetic association studies in humans have found evidence for similar relationships between growth factor signaling pathways and neuropsychiatric phenotypes. Accumulating data suggest that dysfunction in neuronal circuitry, caused by defects in growth factor-mediated synapse formation, contributes to the susceptibility to multiple neuropsychiatric diseases, including epilepsy, autism, and disorders of thought and mood (e.g., schizophrenia and bipolar disorder, respectively). In this review, we will focus on how specific synaptogenic growth factors and their downstream signaling pathways might be involved in the development of neuropsychiatric diseases.
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Affiliation(s)
- Aislinn J Williams
- Department of Psychiatry, University of Michigan Ann Arbor, MI, USA ; Molecular and Behavioral Neuroscience Institute, University of Michigan Ann Arbor, MI, USA
| | - Hisashi Umemori
- Molecular and Behavioral Neuroscience Institute, University of Michigan Ann Arbor, MI, USA ; Department of Neurology, F.M. Kirby Neurobiology Center, Harvard Medical School, Boston Children's Hospital Boston, MA, USA
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Acute and chronic effects of ethanol on learning-related synaptic plasticity. Alcohol 2014; 48:1-17. [PMID: 24447472 DOI: 10.1016/j.alcohol.2013.09.045] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 09/16/2013] [Accepted: 09/18/2013] [Indexed: 11/23/2022]
Abstract
Alcoholism is associated with acute and long-term cognitive dysfunction including memory impairment, resulting in substantial disability and cost to society. Thus, understanding how ethanol impairs cognition is essential for developing treatment strategies to dampen its adverse impact. Memory processing is thought to involve persistent, use-dependent changes in synaptic transmission, and ethanol alters the activity of multiple signaling molecules involved in synaptic processing, including modulation of the glutamate and gamma-aminobutyric acid (GABA) transmitter systems that mediate most fast excitatory and inhibitory transmission in the brain. Effects on glutamate and GABA receptors contribute to ethanol-induced changes in long-term potentiation (LTP) and long-term depression (LTD), forms of synaptic plasticity thought to underlie memory acquisition. In this paper, we review the effects of ethanol on learning-related forms of synaptic plasticity with emphasis on changes observed in the hippocampus, a brain region that is critical for encoding contextual and episodic memories. We also include studies in other brain regions as they pertain to altered cognitive and mental function. Comparison of effects in the hippocampus to other brain regions is instructive for understanding the complexities of ethanol's acute and long-term pharmacological consequences.
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Abstract
Throughout development, the nervous system produces patterned spontaneous activity. Research over the past two decades has revealed a core group of mechanisms that mediate spontaneous activity in diverse circuits. Many circuits engage several of these mechanisms sequentially to accommodate developmental changes in connectivity. In addition to shared mechanisms, activity propagates through developing circuits and neuronal pathways (i.e., linked circuits in different brain areas) in stereotypic patterns. Increasing evidence suggests that spontaneous network activity shapes synaptic development in vivo Variations in activity-dependent plasticity may explain how similar mechanisms and patterns of activity can be employed to establish diverse circuits. Here, I will review common mechanisms and patterns of spontaneous activity in emerging neural networks and discuss recent insights into their contribution to synaptic development.
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Affiliation(s)
- Daniel Kerschensteiner
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, MO, USA Department of Anatomy and Neurobiology, Washington University School of Medicine, Saint Louis, MO, USA Hope Center for Neurological Disorders, Washington University School of Medicine, Saint Louis, MO, USA
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Sitdikova G, Zakharov A, Janackova S, Gerasimova E, Lebedeva J, Inacio AR, Zaynutdinova D, Minlebaev M, Holmes GL, Khazipov R. Isoflurane suppresses early cortical activity. Ann Clin Transl Neurol 2013; 1:15-26. [PMID: 25356379 PMCID: PMC4207500 DOI: 10.1002/acn3.16] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 09/29/2013] [Accepted: 09/30/2013] [Indexed: 11/08/2022] Open
Abstract
Objective Isoflurane and other volatile anesthetics are widely used in children to induce deep and reversible coma, but they may also exert neurotoxic actions. The effects of volatile anesthetics on the immature brain activity remain elusive, however. Methods The effects of isoflurane on spontaneous and sensory-evoked activity were explored using intracortical extracellular field potential and multiple unit recordings in the rat barrel cortex from birth to adulthood. Results During the first postnatal week, isoflurane suppressed cortical activity in a concentration-dependent manner. At surgical anesthesia levels (1.5–2%), isoflurane completely suppressed the electroencephalogram and silenced cortical neurons. Although sensory potentials evoked by the principal whisker deflection persisted, sensory-evoked early gamma and spindle-burst oscillations were completely suppressed by isoflurane. Isoflurane-induced burst-suppression pattern emerged during the second postnatal week and matured through the first postnatal month. Bursts in adolescent and adult rats were characterized by activation of entire cortical columns with a leading firing of infragranular neurons, and were triggered by principal and adjacent whiskers stimulation, and by auditory and visual stimuli, indicating an involvement of horizontal connections in their generation and horizontal spread. Interpretation The effects of isoflurane on cortical activity shift from total suppression of activity to burst-suppression pattern at the end of the first postnatal week. Developmental emergence of bursts likely involves a development of the intracortical short-and long-range connections. We hypothesize that complete suppression of cortical activity under isoflurane anesthesia during the first postnatal week may explain neuronal apoptosis stimulated by volatile anesthetics in the neonatal rats.
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Affiliation(s)
- Guzel Sitdikova
- INMED, INSERM U-901 Marseille, France ; Aix-Marseille University Marseille, France ; Laboratory of Neurobiology, Kazan Federal University Kazan, Russia
| | - Andrei Zakharov
- Laboratory of Neurobiology, Kazan Federal University Kazan, Russia
| | - Sona Janackova
- INMED, INSERM U-901 Marseille, France ; Aix-Marseille University Marseille, France
| | - Elena Gerasimova
- Laboratory of Neurobiology, Kazan Federal University Kazan, Russia
| | - Julia Lebedeva
- Laboratory of Neurobiology, Kazan Federal University Kazan, Russia
| | - Ana R Inacio
- Aix-Marseille University Marseille, France ; Laboratory of Neurobiology, Kazan Federal University Kazan, Russia
| | - Dilyara Zaynutdinova
- Aix-Marseille University Marseille, France ; Laboratory of Neurobiology, Kazan Federal University Kazan, Russia
| | - Marat Minlebaev
- INMED, INSERM U-901 Marseille, France ; Aix-Marseille University Marseille, France ; Laboratory of Neurobiology, Kazan Federal University Kazan, Russia
| | - Gregory L Holmes
- Department of Neurological Sciences, University of Vermont College of Medicine Burlington, Vermont
| | - Roustem Khazipov
- INMED, INSERM U-901 Marseille, France ; Aix-Marseille University Marseille, France ; Laboratory of Neurobiology, Kazan Federal University Kazan, Russia
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Ambrogini P, Lattanzi D, Ciuffoli S, Betti M, Fanelli M, Cuppini R. Physical exercise and environment exploration affect synaptogenesis in adult-generated neurons in the rat dentate gyrus: possible role of BDNF. Brain Res 2013; 1534:1-12. [PMID: 23973748 DOI: 10.1016/j.brainres.2013.08.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 08/06/2013] [Accepted: 08/12/2013] [Indexed: 01/02/2023]
Abstract
A brief training in a pool maze, with or without cognitive tasks, modifies the synaptogenesis and maturation of newborn neurons in adult rat dentate gyrus. These types of trainings have many aspects, including physical activity and exploration. Therefore, to evaluate whether physical exercise and environment exploration are able to affect synapse formation and the maturation of adult-generated neurons, GFP-retrovirus infusion was performed on rats which, on the fourth day after injection, were housed under running conditions or allowed to explore an enriched environment briefly in the absence of exercise for the following three days. Afterward, at the end of the trainings, electrophysiological and morphological studies were conducted. Considering that neurotrophic factors increase after exercise or environment exploration, hippocampal BDNF levels and TrkB receptor activation were evaluated. In this study, we show that both spontaneous physical activity and enriched environment exploration induced synaptogenesis and T-type voltage-dependent Ca(2+) currents in very immature neurons. Hippocampal BDNF levels and TrkB receptor activation were determined to be increasing following physical activity and exploration. A possible contribution of BDNF signaling in mediating the observed effects was supported by the use of 7-8-dihydroxyflavone, a selective TrkB agonist, and of ANA-12, an inhibitor of TrkB receptors.
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Affiliation(s)
- P Ambrogini
- Department of Earth, Life and Environment Sciences, Section of Physiology, University of Urbino "Carlo Bo", Urbino 61029, Italy.
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Rothman SM, Mattson MP. Activity-dependent, stress-responsive BDNF signaling and the quest for optimal brain health and resilience throughout the lifespan. Neuroscience 2013; 239:228-40. [PMID: 23079624 PMCID: PMC3629379 DOI: 10.1016/j.neuroscience.2012.10.014] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 09/24/2012] [Accepted: 10/05/2012] [Indexed: 12/31/2022]
Abstract
During development of the nervous system, the formation of connections (synapses) between neurons is dependent upon electrical activity in those neurons, and neurotrophic factors produced by target cells play a pivotal role in such activity-dependent sculpting of the neural networks. A similar interplay between neurotransmitter and neurotrophic factor signaling pathways mediates adaptive responses of neural networks to environmental demands in adult mammals, with the excitatory neurotransmitter glutamate and brain-derived neurotrophic factor (BDNF) being particularly prominent regulators of synaptic plasticity throughout the central nervous system. Optimal brain health throughout the lifespan is promoted by intermittent challenges such as exercise, cognitive stimulation and dietary energy restriction, that subject neurons to activity-related metabolic stress. At the molecular level, such challenges to neurons result in the production of proteins involved in neurogenesis, learning and memory and neuronal survival; examples include proteins that regulate mitochondrial biogenesis, protein quality control, and resistance of cells to oxidative, metabolic and proteotoxic stress. BDNF signaling mediates up-regulation of several such proteins including the protein chaperone GRP-78, antioxidant enzymes, the cell survival protein Bcl-2, and the DNA repair enzyme APE1. Insufficient exposure to such challenges, genetic factors may conspire to impair BDNF production and/or signaling resulting in the vulnerability of the brain to injury and neurodegenerative disorders including Alzheimer's, Parkinson's and Huntington's diseases. Further, BDNF signaling is negatively regulated by glucocorticoids. Glucocorticoids impair synaptic plasticity in the brain by negatively regulating spine density, neurogenesis and long-term potentiation, effects that are potentially linked to glucocorticoid regulation of BDNF. Findings suggest that BDNF signaling in specific brain regions mediates some of the beneficial effects of exercise and energy restriction on peripheral energy metabolism and the cardiovascular system. Collectively, the findings described in this article suggest the possibility of developing prescriptions for optimal brain health based on activity-dependent BDNF signaling.
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Affiliation(s)
- S M Rothman
- Laboratory of Neurosciences, National Institute on Aging, Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MD 21224, USA.
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Satb1 is an activity-modulated transcription factor required for the terminal differentiation and connectivity of medial ganglionic eminence-derived cortical interneurons. J Neurosci 2013; 32:17690-705. [PMID: 23223290 DOI: 10.1523/jneurosci.3583-12.2012] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Although previous work identified transcription factors crucial for the specification and migration of parvalbumin (PV)-expressing and somatostatin (SST)-expressing interneurons, the intrinsic factors required for the terminal differentiation, connectivity, and survival of these cell types remain uncharacterized. Here we demonstrate that, within subpopulations of cortical interneurons, Satb1 (special AT-rich binding protein) promotes terminal differentiation, connectivity, and survival in interneurons that express PV and SST. We find that conditional removal of Satb1 in mouse interneurons results in the loss of a majority of SST-expressing cells across all cortical layers, as well as some PV-expressing cells in layers IV and VI, by postnatal day 21. SST-expressing cells initially migrate to the cortex in Satb1 mutant mice, but receive reduced levels of afferent input and begin to die during the first postnatal week. Electrophysiological characterization indicates that loss of Satb1 function in interneurons results in a loss of functional inhibition of excitatory principal cells. These data suggest that Satb1 is required for medial ganglionic eminence-derived interneuron differentiation, connectivity, and survival.
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McRae PA, Porter BE. The perineuronal net component of the extracellular matrix in plasticity and epilepsy. Neurochem Int 2012; 61:963-72. [PMID: 22954428 DOI: 10.1016/j.neuint.2012.08.007] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 08/13/2012] [Accepted: 08/15/2012] [Indexed: 12/20/2022]
Abstract
During development the extracellular matrix (ECM) of the central nervous system (CNS) facilitates proliferation, migration, and synaptogenesis. In the mature nervous system due to changes in the ECM it provides structural stability and impedes proliferation, migration, and synaptogensis. The perineuronal net (PN) is a specialized ECM structure found primarily surrounding inhibitory interneurons where it forms a mesh-like structure around points of synaptic contact. The PN organizes the extracellular space by binding multiple components of the ECM and bringing them into close proximity to the cell membrane, forming dense aggregates surrounding synapses. The PN is expressed late in postnatal development when the nervous system is in the final stages of maturation and the critical periods are closing. Once fully expressed the PN envelopes synapses and leads to decreased plasticity and increases synaptic stability in the CNS. Disruptions in the PN have been studied in a number of disease states including epilepsy. Epilepsy is one of the most common neurologic disorders characterized by excessive neuronal activity which results in recurrent spontaneous seizures. A shift in the delicate balance between excitation and inhibition is believed to be one of the underlying mechanisms in the development of epilepsy. During epileptogenesis, the brain undergoes numerous changes including synaptic rearrangement and axonal sprouting, which require structural plasticity. Because of the PNs location around inhibitory cells and its role in limiting plasticity, the PN is an important candidate for altering the progression of epilepsy. In this review, an overview of the ECM and PN in the CNS will be presented with special emphasis on potential roles in epileptogenesis.
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Affiliation(s)
- Paulette A McRae
- Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
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Nimmervoll B, White R, Yang JW, An S, Henn C, Sun JJ, Luhmann HJ. LPS-induced microglial secretion of TNFα increases activity-dependent neuronal apoptosis in the neonatal cerebral cortex. ACTA ACUST UNITED AC 2012; 23:1742-55. [PMID: 22700645 DOI: 10.1093/cercor/bhs156] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
During the pre- and neonatal period, the cerebral cortex reveals distinct patterns of spontaneous synchronized activity, which is critically involved in the formation of early networks and in the regulation of neuronal survival and programmed cell death (apoptosis). During this period, the cortex is also highly vulnerable to inflammation and in humans prenatal infection may have a profound impact on neurodevelopment causing long-term neurological deficits. Using in vitro and in vivo multi-electrode array recordings and quantification of caspase-3 (casp-3)-dependent apoptosis, we demonstrate that lipopolysaccharide-induced inflammation causes rapid alterations in the pattern of spontaneous burst activities, which subsequently leads to an increase in apoptosis. We show that these inflammatory effects are specifically initiated by the microglia-derived pro-inflammatory cytokine tumor necrosis factor α and the chemokine macrophage inflammatory protein 2. Our data demonstrate that inflammation-induced modifications in spontaneous network activities influence casp-3-dependent cell death in the developing cerebral cortex.
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Affiliation(s)
- Birgit Nimmervoll
- Institute of Physiology and Pathophysiology, University Medical Center, Johannes Gutenberg University, Mainz D-55128, Germany
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Zorumski CF, Izumi Y. NMDA receptors and metaplasticity: mechanisms and possible roles in neuropsychiatric disorders. Neurosci Biobehav Rev 2012; 36:989-1000. [PMID: 22230702 DOI: 10.1016/j.neubiorev.2011.12.011] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 11/14/2011] [Accepted: 12/22/2011] [Indexed: 02/08/2023]
Abstract
N-methyl-D-aspartate receptors (NMDARs) are key components of neural signaling, playing roles in synaptic transmission and in the synaptic plasticity thought to underlie learning and memory. NMDAR activation can also have neurotoxic consequences contributing to several forms of neurodegeneration. Additionally, NMDARs can modulate neuronal function and regulate the ability of synapses to undergo synaptic plasticity. Evidence gathered over the past 20 years strongly supports the idea that untimely activation of NMDARs impairs the induction of long-term potentiation (LTP) by a form of metaplasticity. This metaplasticity can be triggered by multiple stimuli including physiological receptor activation, and metabolic and behavioral stressors. These latter findings raise the possibility that NMDARs contribute to cognitive dysfunction associated with neuropsychiatric disorders. This paper examines NMDAR metaplasticity and its potential role in cognition. Recent studies using NMDAR antagonists for therapeutic purposes also raise the possibility that metaplasticity may contribute to clinical effects of certain drugs.
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Affiliation(s)
- Charles F Zorumski
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Moore AR, Zhou WL, Jakovcevski I, Zecevic N, Antic SD. Physiological Properties of Human Fetal Cortex In Vitro. ISOLATED CENTRAL NERVOUS SYSTEM CIRCUITS 2012. [DOI: 10.1007/978-1-62703-020-5_3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Abstract
Neurons of the central nervous system (CNS) of adult mammals can be damaged in a variety of ways. Most neurons rapidly die after injury. Even if the injured CNS neurons do not die in a short time, the neurons eventually die because they are not able to regenerate their axons to reconnect with their normal targets. In addition, neurons are normally not replaced. Therefore, much work has been directed toward understanding of the molecular regulation of the CNS degeneration following injury, and different experimental strategies are being used to try to protect the damaged neurons. Following axonal lesion, the neurons not only need to survive but also to reconnect to be functionally relevant, and efforts are directed toward not only survival but also axonal regeneration and proper rewiring of injured neurons. Recent experimental data suggest that electrical activity, endogenous or exogenous, can enhance neuronal survival and regeneration in vitro and in vivo. This chapter reviews the evidence that have been obtained on the role of neuronal electrical activity on neuroprotection. We will develop perspectives toward neuroprotection and regeneration of adult lesioned CNS neurons based on electrical activity-dependent cell survival that may be applicable to various diseases of the CNS.
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Uteshev VV. α7 nicotinic ACh receptors as a ligand-gated source of Ca(2+) ions: the search for a Ca(2+) optimum. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:603-38. [PMID: 22453962 DOI: 10.1007/978-94-007-2888-2_27] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The spatiotemporal distribution of cytosolic Ca(2+) ions is a key determinant of neuronal behavior and survival. Distinct sources of Ca(2+) ions including ligand- and voltage-gated Ca(2+) channels contribute to intracellular Ca(2+) homeostasis. Many normal physiological and therapeutic neuronal functions are Ca(2+)-dependent, however an excess of cytosolic Ca(2+) or a lack of the appropriate balance between Ca(2+) entry and clearance may destroy cellular integrity and cause cellular death. Therefore, the existence of optimal spatiotemporal patterns of cytosolic Ca(2+) elevations and thus, optimal activation of ligand- and voltage-gated Ca(2+) ion channels are postulated to benefit neuronal function and survival. Alpha7 nicotinic -acetylcholine receptors (nAChRs) are highly permeable to Ca(2+) ions and play an important role in modulation of neurotransmitter release, gene expression and neuroprotection in a variety of neuronal and non-neuronal cells. In this review, the focus is placed on α7 nAChR-mediated currents and Ca(2+) influx and how this source of Ca(2+) entry compares to NMDA receptors in supporting cytosolic Ca(2+) homeostasis, neuronal function and survival.
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Affiliation(s)
- Victor V Uteshev
- Department of Pharmacology & Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, USA.
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Morgan PJ, Liedmann A, Hübner R, Hovakimyan M, Rolfs A, Frech MJ. Human neural progenitor cells show functional neuronal differentiation and regional preference after engraftment onto hippocampal slice cultures. Stem Cells Dev 2011; 21:1501-12. [PMID: 21867424 DOI: 10.1089/scd.2011.0335] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The transplantation of stem cells offers potential therapies for many neurodegenerative disorders that currently have limited or no treatment options. However, relatively little is known about how the host environment affects the development and integration of these cells. In this study we have engrafted immortalized human midbrain neural progenitor cells (NPCs) onto rat hippocampal brain slice cultures to examine the influence of a neural environment on differentiation. Patch clamp recordings revealed that the transplanted progenitor cells could express neuronal-type voltage-gated currents and rapidly receive synaptic input from the hippocampal brain slice. The distribution of progenitor cells across the hippocampal slices was strongly influenced by the neural architecture, with most cells located in the fissural regions and sending processes parallel to the laminar structure, while in contrast, cells located in the dentate gyrus showed no organized pattern. Almost no cells were found in the stratum radiatum or pyramidal cell layers. Together, these results demonstrate the potential for the architecture of the host environment to regulate the integration of transplanted cells, and highlight the utility of coculture systems for studying the mechanisms underlying the migration, integration, and differentiation of human NPCs in structured neural environments.
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Affiliation(s)
- Peter J Morgan
- Albrecht-Kossel-Institute for Neuroregeneration, University of Rostock, Rostock, Germany
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Wagner-Golbs A, Luhmann HJ. Activity-dependent survival of developing neocortical neurons depends on PI3K signalling. J Neurochem 2011; 120:495-501. [PMID: 22118415 DOI: 10.1111/j.1471-4159.2011.07591.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Spontaneous electrical network activity plays a major role in the control of cell survival in the developing brain. Several intracellular pathways are implicated in transducing electrical activity into gene expression dependent and independent survival signals. These include activation of phosphatidylinositol 3-kinase (PI3K) and its downstream effector Akt, activation of Ras and subsequently MAPK/extracellular signal-regulated kinase (MEK) and extracellular signal-regulated kinase and signalling via calcium/calmodulin-dependent protein kinase (CaMK). In the present study, we analyzed the role of these pathways for the control of neuronal survival in different extracellular potassium concentrations ([K(+) ](ex) ). Organotypic neocortical slice cultures prepared from newborn mice were kept in 5.3, 8.0 and 25.0mM [K(+) ](ex) and treated with specific inhibitors of PI3K, MEK1, CaMKK and a broad spectrum CaMK inhibitor. After 6h of incubation, slices were immunostained for activated caspase 3 (a-caspase 3) and the number of apoptotic cells was quantified by computer based analysis. We found that in 5.3 and 8.0mM [K(+) ](ex) only PI3K was important for neuronal survival. When [K(+) ](ex) was raised to 25.0mM, a concentration above the depolarization block, we found no influence of PI3K on neuronal survival. Our data demonstrate that only the PI3K pathway, and not the MEK1, CaMKK or CaMKs pathway, plays a central role in the regulation of activity-dependent neuronal survival in the developing cerebral cortex.
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Affiliation(s)
- Antje Wagner-Golbs
- Institute of Physiology and Pathophysiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, Mainz, Germany
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Hogins J, Crawford DC, Zorumski CF, Mennerick S. Excitotoxicity triggered by Neurobasal culture medium. PLoS One 2011; 6:e25633. [PMID: 21980512 PMCID: PMC3182245 DOI: 10.1371/journal.pone.0025633] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 09/08/2011] [Indexed: 01/13/2023] Open
Abstract
Neurobasal defined culture medium has been optimized for survival of rat embryonic hippocampal neurons and is now widely used for many types of primary neuronal cell culture. Therefore, we were surprised that routine medium exchange with serum- and supplement-free Neurobasal killed as many as 50% of postnatal hippocampal neurons after a 4 h exposure at day in vitro 12–15. Minimal Essential Medium (MEM), in contrast, produced no significant toxicity. Detectable Neurobasal-induced neuronal death occurred with as little as 5 min exposure, measured 24 h later. D-2-Amino-5-phosphonovalerate (D-APV) completely prevented Neurobasal toxicity, implicating direct or indirect N-methyl-D-aspartate (NMDA) receptor-mediated neuronal excitotoxicity. Whole-cell recordings revealed that Neurobasal but not MEM directly activated D-APV-sensitive currents similar in amplitude to those gated by 1 µM glutamate. We hypothesized that L-cysteine likely mediates the excitotoxic effects of Neurobasal incubation. Although the original published formulation of Neurobasal contained only 10 µM L-cysteine, commercial recipes contain 260 µM, a concentration in the range reported to activate NMDA receptors. Consistent with our hypothesis, 260 µM L-cysteine in bicarbonate-buffered saline gated NMDA receptor currents and produced toxicity equivalent to Neurobasal. Although NMDA receptor-mediated depolarization and Ca2+ influx may support survival of young neurons, NMDA receptor agonist effects on development and survival should be considered when employing Neurobasal culture medium.
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Affiliation(s)
- Joshua Hogins
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Devon C. Crawford
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Graduate Program in Neuroscience, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Charles F. Zorumski
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Anatomy & Neurobiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Steven Mennerick
- Departments of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Anatomy & Neurobiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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Stoyanova II, Rutten WLC, le Feber J. Orexin a in cortical cultures: expression and effect on synaptogenesis during development. Cell Mol Neurobiol 2011; 32:49-57. [PMID: 21739363 PMCID: PMC3260436 DOI: 10.1007/s10571-011-9733-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 06/24/2011] [Indexed: 11/29/2022]
Abstract
Orexin A (OXA) is an excitatory hypothalamic neurotransmitter and ligand for Orexin Receptor-1 (OR1), isolated from a small group of hypothalamic neurons. OXA orchestrates different brain functions, and at the cognitive level some of the effects of insufficiency of OXA are well-known, for example in Parkinson’s disease. It is widely assumed that deteriorated cognitive processes are related to impaired network connectivity. However, little is known about the effects of OXA in network connectivity and synaptogenesis. Therefore, to obtain insight into this problem we designed experiments with two groups of networks of dissociated cortical neurons: one group incubated in a plain medium and another chronically treated with OXA. After 1, 2, 3 or 4 weeks in vitro we applied immunocytochemistry for detection of OXA, OR1, and synaptic marker synaptophysin. Shortly after plating, 91 ± 8% of the neurons cultivated in a plain medium expressed OXA-immunoreactivity, which does normally not occur in vivo indicating that neurons may change their phenotype under non-natural culture conditions to develop synaptically coupled networks. The fraction of orexinergic neurons decreased to 33 ± 21% after 4 weeks in vitro. OXA expression was highest in the first week of network formation, the period of maximum synaptogenesis, and then decreased and stabilized in the weeks thereafter. Our hypothesis that OXA plays a role in the network development as a synaptogenic factor was supported by higher levels, earlier onset, and sustained increase of synaptophysin expression in experiments with chronic OXA application to the culture medium.
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Affiliation(s)
- Irina I Stoyanova
- Neural Engineering Department, Institute for Biomedical Engineering and Technical Medicine MIRA, University of Twente, BSS, ZH 226, P. O. Box 217, 7500, AE, Enschede, The Netherlands.
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