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Thome C, Janssen JM, Karabulut S, Acuna C, D’Este E, Soyka SJ, Baum K, Bock M, Lehmann N, Roos J, Stevens NA, Hasegawa M, Ganea DA, Benoit CM, Gründemann J, Min L, Bird KM, Schultz C, Bennett V, Jenkins PM, Engelhardt M. Live imaging of excitable axonal microdomains in ankyrin-G-GFP mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.02.01.525891. [PMID: 38948770 PMCID: PMC11212890 DOI: 10.1101/2023.02.01.525891] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
The axon initial segment (AIS) constitutes not only the site of action potential initiation, but also a hub for activity-dependent modulation of output generation. Recent studies shedding light on AIS function used predominantly post-hoc approaches since no robust murine in vivo live reporters exist. Here, we introduce a reporter line in which the AIS is intrinsically labeled by an ankyrin-G-GFP fusion protein activated by Cre recombinase, tagging the native Ank3 gene. Using confocal, superresolution, and two-photon microscopy as well as whole-cell patch-clamp recordings in vitro, ex vivo, and in vivo, we confirm that the subcellular scaffold of the AIS and electrophysiological parameters of labeled cells remain unchanged. We further uncover rapid AIS remodeling following increased network activity in this model system, as well as highly reproducible in vivo labeling of AIS over weeks. This novel reporter line allows longitudinal studies of AIS modulation and plasticity in vivo in real-time and thus provides a unique approach to study subcellular plasticity in a broad range of applications.
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Affiliation(s)
- Christian Thome
- Institute of Anatomy and Cell Biology, Johannes Kepler University, 4020 Linz, Austria
- Clinical Research Institute of Neuroscience, Johannes Kepler University, 4020 Linz, Austria
- Institute of Physiology and Pathophysiology, Heidelberg University, 69120 Heidelberg, Germany
| | - Jan Maximilian Janssen
- Institute of Anatomy and Cell Biology, Johannes Kepler University, 4020 Linz, Austria
- Clinical Research Institute of Neuroscience, Johannes Kepler University, 4020 Linz, Austria
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Seda Karabulut
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Claudio Acuna
- Chica and Heinz Schaller Research Group, Institute of Anatomy and Cell Biology, Heidelberg University, 69120 Heidelberg, Germany
| | - Elisa D’Este
- Optical Microscopy Facility, Max Planck Institute for Medical Research, 69120 Heidelberg, Germany
| | - Stella J. Soyka
- Institute of Anatomy and Cell Biology, Dept. of Functional Neuroanatomy, Heidelberg University, 69120 Heidelberg, Germany
| | - Konrad Baum
- Institute of Anatomy and Cell Biology, Johannes Kepler University, 4020 Linz, Austria
- Clinical Research Institute of Neuroscience, Johannes Kepler University, 4020 Linz, Austria
| | - Michael Bock
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Nadja Lehmann
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Johannes Roos
- Institute of Anatomy and Cell Biology, Johannes Kepler University, 4020 Linz, Austria
- Clinical Research Institute of Neuroscience, Johannes Kepler University, 4020 Linz, Austria
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Nikolas A. Stevens
- Institute of Physiology and Pathophysiology, Heidelberg University, 69120 Heidelberg, Germany
| | - Masashi Hasegawa
- German Center for Neurodegenerative Disease (DZNE), Neural Circuit Computations, 53127 Bonn, Germany
| | - Dan A. Ganea
- University of Basel, Department of Biomedicine, 4031 Basel, Switzerland
| | - Chloé M. Benoit
- German Center for Neurodegenerative Disease (DZNE), Neural Circuit Computations, 53127 Bonn, Germany
- University of Basel, Department of Biomedicine, 4031 Basel, Switzerland
| | - Jan Gründemann
- German Center for Neurodegenerative Disease (DZNE), Neural Circuit Computations, 53127 Bonn, Germany
- University of Basel, Department of Biomedicine, 4031 Basel, Switzerland
| | - Lia Min
- Departments of Pharmacology and Psychiatry, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Kalynn M. Bird
- Departments of Pharmacology and Psychiatry, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Christian Schultz
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Vann Bennett
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | - Paul M. Jenkins
- Departments of Pharmacology and Psychiatry, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Maren Engelhardt
- Institute of Anatomy and Cell Biology, Johannes Kepler University, 4020 Linz, Austria
- Clinical Research Institute of Neuroscience, Johannes Kepler University, 4020 Linz, Austria
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
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Wen W, Turrigiano GG. Modular Arrangement of Synaptic and Intrinsic Homeostatic Plasticity within Visual Cortical Circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.01.596982. [PMID: 38853882 PMCID: PMC11160741 DOI: 10.1101/2024.06.01.596982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Neocortical circuits use synaptic and intrinsic forms of homeostatic plasticity to stabilize key features of network activity, but whether these different homeostatic mechanisms act redundantly, or can be independently recruited to stabilize different network features, is unknown. Here we used pharmacological and genetic perturbations both in vitro and in vivo to determine whether synaptic scaling and intrinsic homeostatic plasticity (IHP) are arranged and recruited in a hierarchical or modular manner within L2/3 pyramidal neurons in rodent V1. Surprisingly, although the expression of synaptic scaling and IHP was dependent on overlapping trafficking pathways, they could be independently recruited by manipulating spiking activity or NMDAR signaling, respectively. Further, we found that changes in visual experience that affect NMDAR activation but not mean firing selectively trigger IHP, without recruiting synaptic scaling. These findings support a modular model in which synaptic and intrinsic homeostatic plasticity respond to and stabilize distinct aspects of network activity.
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Affiliation(s)
- Wei Wen
- Department of Biology, Brandeis University, Waltham, MA 02453, USA
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Burnett LE, Koppensteiner P, Symonova O, Masson T, Vega-Zuniga T, Contreras X, Rülicke T, Shigemoto R, Novarino G, Joesch M. Shared behavioural impairments in visual perception and place avoidance across different autism models are driven by periaqueductal grey hypoexcitability in Setd5 haploinsufficient mice. PLoS Biol 2024; 22:e3002668. [PMID: 38857283 PMCID: PMC11216578 DOI: 10.1371/journal.pbio.3002668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 07/01/2024] [Accepted: 05/07/2024] [Indexed: 06/12/2024] Open
Abstract
Despite the diverse genetic origins of autism spectrum disorders (ASDs), affected individuals share strikingly similar and correlated behavioural traits that include perceptual and sensory processing challenges. Notably, the severity of these sensory symptoms is often predictive of the expression of other autistic traits. However, the origin of these perceptual deficits remains largely elusive. Here, we show a recurrent impairment in visual threat perception that is similarly impaired in 3 independent mouse models of ASD with different molecular aetiologies. Interestingly, this deficit is associated with reduced avoidance of threatening environments-a nonperceptual trait. Focusing on a common cause of ASDs, the Setd5 gene mutation, we define the molecular mechanism. We show that the perceptual impairment is caused by a potassium channel (Kv1)-mediated hypoexcitability in a subcortical node essential for the initiation of escape responses, the dorsal periaqueductal grey (dPAG). Targeted pharmacological Kv1 blockade rescued both perceptual and place avoidance deficits, causally linking seemingly unrelated trait deficits to the dPAG. Furthermore, we show that different molecular mechanisms converge on similar behavioural phenotypes by demonstrating that the autism models Cul3 and Ptchd1, despite having similar behavioural phenotypes, differ in their functional and molecular alteration. Our findings reveal a link between rapid perception controlled by subcortical pathways and appropriate learned interactions with the environment and define a nondevelopmental source of such deficits in ASD.
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Affiliation(s)
- Laura E. Burnett
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Olga Symonova
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Tomás Masson
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Tomas Vega-Zuniga
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Ximena Contreras
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Thomas Rülicke
- Department of Biomedical Sciences and Ludwig Boltzmann Institute for Hematology and Oncology, University of Veterinary Medicine, Vienna, Austria
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Gaia Novarino
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Maximilian Joesch
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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Wang X, Lu T, Cai Z, Han D, Ye X, Liu Z. A Photoelectrochemical Sensor for Real-Time Monitoring of Neurochemical Signals in the Brain of Awake Animals. Anal Chem 2024; 96:6079-6088. [PMID: 38563576 DOI: 10.1021/acs.analchem.4c00934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Metal ion homeostasis is imperative for normal functioning of the brain. Considering the close association between brain metal ions and various pathological processes in brain diseases, it becomes essential to track their dynamics in awake animals for accurate physiological insights. Although ion-selective microelectrodes (ISMEs) have demonstrated great advantage in recording ion signals in awake animals, their intrinsic potential drift impairs their accuracy in long-term in vivo analysis. This study addresses the challenge by integrating ISMEs with photoelectrochemical (PEC) sensing, presenting an excitation-detection separated PEC platform based on potential regulation of ISMEs. A flexible indium tin oxide (Flex-ITO) electrode, modified with MoS2 nanosheets and Au NPs, serves as the photoelectrode and is integrated with a micro-LED. The integrated photoelectrode is placed on the rat skull to remain unaffected by animal activity. The potential of ISME dependent on the concentration of target K+ serves as the modulator of the photocurrent signal of the photoelectrode. The proposed design allows deep brain detection while minimizing interference with neurons, thus enabling real-time monitoring of neurochemical signals in awake animals. It successfully monitors changes in extracellular K+ levels in the rat brain after exposure to PM2.5, presenting a valuable analytical tool for understanding the impact of environmental factors on the nervous system.
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Affiliation(s)
- Xiao Wang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Tao Lu
- College of Health Science and Engineering, Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, China
| | - Zirui Cai
- College of Health Science and Engineering, Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, China
| | - Dongfang Han
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Xiaoxue Ye
- College of Health Science and Engineering, Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, China
| | - Zhihong Liu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
- College of Health Science and Engineering, Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei University, Wuhan 430062, China
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Wang W, Zhang Y, Li X, E Q, Jiang Z, Shi Q, Huang Y, Wang J, Huang Y. KCNA1 promotes the growth and invasion of glioblastoma cells through ferroptosis inhibition via upregulating SLC7A11. Cancer Cell Int 2024; 24:7. [PMID: 38172959 PMCID: PMC10765868 DOI: 10.1186/s12935-023-03199-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 12/27/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND The high invasiveness and infiltrative nature of Glioblastoma (GBM) pose significant challenges for surgical removal. This study aimed to investigate the role of KCNA1 in GBM progression. METHODS CCK8, colony formation assay, scratch assay, transwell assay, and 3D tumor spheroid invasion assays were to determine how KCNA1 affects the growth and invasion of GBM cells. Subsequently, to confirm the impact of KCNA1 in ferroptosis, western blot, transmission electron microscopy and flow cytometry were conducted. To ascertain the impact of KCNA1 in vivo, patient-derived orthotopic xenograft models were established. RESULTS In functional assays, KCNA1 promotes the growth and invasion of GBM cells. Besides, KCNA1 can increase the expression of SLC7A11 and protect cells from ferroptosis. The vivo experiments demonstrated that knocking down KCNA1 inhibited the growth and infiltration of primary tumors in mice and extended survival time. CONCLUSION Therefore, our research suggests that KCNA1 may promote tumor growth and invasion by upregulating the expression of SLC7A11 and inhibiting ferroptosis, making it a promising therapeutic target for GBM.
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Affiliation(s)
- Weichao Wang
- Department of Neurosurgery, Dushu Lake Hospital Affiliated of Soochow University, Suzhou, 215000, China
| | - Yang Zhang
- Department of Neurosurgery, Dushu Lake Hospital Affiliated of Soochow University, Suzhou, 215000, China
- Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, 215000, China
| | - Xuetao Li
- Department of Neurosurgery, Dushu Lake Hospital Affiliated of Soochow University, Suzhou, 215000, China
| | - Qinzi E
- Department of Neurosurgery, Dushu Lake Hospital Affiliated of Soochow University, Suzhou, 215000, China
| | - Zuoyu Jiang
- Department of Neurosurgery, Dushu Lake Hospital Affiliated of Soochow University, Suzhou, 215000, China
| | - Qikun Shi
- Department of Neurosurgery, Dushu Lake Hospital Affiliated of Soochow University, Suzhou, 215000, China
| | - Yu Huang
- Department of Neurosurgery, Dushu Lake Hospital Affiliated of Soochow University, Suzhou, 215000, China
| | - Jian Wang
- Department of Neurosurgery, TaiCang Hospital of Traditional Chinese Medicine, Suzhou, 215000, China.
| | - Yulun Huang
- Department of Neurosurgery, Dushu Lake Hospital Affiliated of Soochow University, Suzhou, 215000, China.
- Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, 215000, China.
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Extrémet J, Ramirez-Franco J, Fronzaroli-Molinieres L, Boumedine-Guignon N, Ankri N, El Far O, Garrido JJ, Debanne D, Russier M. Rescue of Normal Excitability in LGI1-Deficient Epileptic Neurons. J Neurosci 2023; 43:8596-8606. [PMID: 37863654 PMCID: PMC10727174 DOI: 10.1523/jneurosci.0701-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 09/08/2023] [Accepted: 10/14/2023] [Indexed: 10/22/2023] Open
Abstract
Leucine-rich glioma inactivated 1 (LGI1) is a glycoprotein secreted by neurons, the deletion of which leads to autosomal dominant lateral temporal lobe epilepsy. We previously showed that LGI1 deficiency in a mouse model (i.e., knock-out for LGI1 or KO-Lgi1) decreased Kv1.1 channel density at the axon initial segment (AIS) and at presynaptic terminals, thus enhancing both intrinsic excitability and glutamate release. However, it is not known whether normal excitability can be restored in epileptic neurons. Here, we show that the selective expression of LGI1 in KO-Lgi1 neurons from mice of both sexes, using single-cell electroporation, reduces intrinsic excitability and restores both the Kv1.1-mediated D-type current and Kv1.1 channels at the AIS. In addition, we show that the homeostatic-like shortening of the AIS length observed in KO-Lgi1 neurons is prevented in neurons electroporated with the Lgi1 gene. Furthermore, we reveal a spatial gradient of intrinsic excitability that is centered on the electroporated neuron. We conclude that expression of LGI1 restores normal excitability through functional Kv1 channels at the AIS.SIGNIFICANCE STATEMENT The lack of leucine-rich glioma inactivated 1 (LGI1) protein induces severe epileptic seizures that leads to death. Enhanced intrinsic and synaptic excitation in KO-Lgi1 mice is because of the decrease in Kv1.1 channels in CA3 neurons. However, the conditions to restore normal excitability profile in epileptic neurons remain to be defined. We show here that the expression of LGI1 in KO-Lgi1 neurons in single neurons reduces intrinsic excitability, and restores both the Kv1.1-mediated D-type current and Kv1.1 channels at the axon initial segment (AIS). Furthermore, the homeostatic shortening of the AIS length observed in KO-Lgi1 neurons is prevented in neurons in which the Lgi1 gene has been rescued. We conclude that LGI1 constitutes a critical factor to restore normal excitability in epileptic neurons.
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Affiliation(s)
- Johanna Extrémet
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Jorge Ramirez-Franco
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Laure Fronzaroli-Molinieres
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Norah Boumedine-Guignon
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Norbert Ankri
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Oussama El Far
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Juan José Garrido
- Cajal Institute, Consejo Superior de Investigaciones Cientificas, Madrid, 28002, Spain
| | - Dominique Debanne
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
| | - Michaël Russier
- Unité de Neurobiologie des canaux Ioniques et de la Synapse, Unité Mixte de Recherche 1072, Institut National de la Santé et de la Recherche Médicale, Aix-Marseille Université, Marseille, 13015, France
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Garrido JJ. Contribution of Axon Initial Segment Structure and Channels to Brain Pathology. Cells 2023; 12:cells12081210. [PMID: 37190119 DOI: 10.3390/cells12081210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 04/17/2023] [Accepted: 04/20/2023] [Indexed: 05/17/2023] Open
Abstract
Brain channelopathies are a group of neurological disorders that result from genetic mutations affecting ion channels in the brain. Ion channels are specialized proteins that play a crucial role in the electrical activity of nerve cells by controlling the flow of ions such as sodium, potassium, and calcium. When these channels are not functioning properly, they can cause a wide range of neurological symptoms such as seizures, movement disorders, and cognitive impairment. In this context, the axon initial segment (AIS) is the site of action potential initiation in most neurons. This region is characterized by a high density of voltage-gated sodium channels (VGSCs), which are responsible for the rapid depolarization that occurs when the neuron is stimulated. The AIS is also enriched in other ion channels, such as potassium channels, that play a role in shaping the action potential waveform and determining the firing frequency of the neuron. In addition to ion channels, the AIS contains a complex cytoskeletal structure that helps to anchor the channels in place and regulate their function. Therefore, alterations in this complex structure of ion channels, scaffold proteins, and specialized cytoskeleton may also cause brain channelopathies not necessarily associated with ion channel mutations. This review will focus on how the AISs structure, plasticity, and composition alterations may generate changes in action potentials and neuronal dysfunction leading to brain diseases. AIS function alterations may be the consequence of voltage-gated ion channel mutations, but also may be due to ligand-activated channels and receptors and AIS structural and membrane proteins that support the function of voltage-gated ion channels.
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Affiliation(s)
- Juan José Garrido
- Instituto Cajal, CSIC, 28002 Madrid, Spain
- Alzheimer's Disease and Other Degenerative Dementias, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), 28002 Madrid, Spain
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Mocci I, Casu MA, Sogos V, Liscia A, Angius R, Cadeddu F, Fanti M, Muroni P, Talani G, Diana A, Collu M, Setzu MD. Effects of memantine on mania-like phenotypes exhibited by Drosophila Shaker mutants. CNS Neurosci Ther 2023. [PMID: 36942502 DOI: 10.1111/cns.14145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/17/2023] [Accepted: 02/19/2023] [Indexed: 03/23/2023] Open
Abstract
INTRODUCTION Increased glutamate levels and electrolytic fluctuations have been observed in acutely manic patients. Despite some efficacy of the non-competitive NMDA receptor antagonist memantine (Mem), such as antidepressant-like and mood-stabilizer drugs in clinical studies, its specific mechanisms of action are still uncertain. The present study aims to better characterize the Drosophila melanogaster fly Shaker mutants (SH), as a translational model of manic episodes within bipolar disorder in humans, and to investigate the potential anti-manic properties of Mem. METHODS AND RESULTS Our findings showed typical behavioral abnormalities in SH, which mirrored with the overexpression of NMDAR-NR1 protein subunit, matched well to glutamate up-regulation. Such molecular features were associated to a significant reduction of SH brain volume in comparison to Wild Type strain flies (WT). Here we report on the ability of Mem treatment to ameliorate behavioral aberrations of SH (similar to that of Lithium), and its ability to reduce NMDAR-NR1 over-expression. CONCLUSIONS Our results show the involvement of the glutamatergic system in the SH, given the interaction between the Shaker channel and the NMDA receptor, suggesting this model as a promising tool for studying the neurobiology of bipolar disorders. Moreover, our results show Mem as a potential disease-modifying therapy, providing insight on new mechanisms of action.
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Affiliation(s)
- Ignazia Mocci
- Institute of Translational Pharmacology, National Research Council, Science and Technology Park of Sardinia, Cagliari, Italy
| | - Maria Antonietta Casu
- Institute of Translational Pharmacology, National Research Council, Science and Technology Park of Sardinia, Cagliari, Italy
| | - Valeria Sogos
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Anna Liscia
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Rossella Angius
- Unit of Biomedical Research Support, NMR Laboratory and Bioanalytical Technologies, Sardegna Ricerche, Science and Technology Park of Sardinia, Cagliari, Italy
| | - Francesca Cadeddu
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Maura Fanti
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Patrizia Muroni
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Giuseppe Talani
- Institute of Neuroscience, National Research Council, Monserrato, Italy
| | - Andrea Diana
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Maria Collu
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Maria Dolores Setzu
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
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ACh Transfers: Homeostatic Plasticity of Cholinergic Synapses. Cell Mol Neurobiol 2023; 43:697-709. [PMID: 35643882 DOI: 10.1007/s10571-022-01227-2] [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: 01/14/2022] [Accepted: 04/25/2022] [Indexed: 11/03/2022]
Abstract
The field of homeostatic plasticity continues to advance rapidly, highlighting the importance of stabilizing neuronal activity within functional limits in the context of numerous fundamental processes such as development, learning, and memory. Most homeostatic plasticity studies have been focused on glutamatergic synapses, while the rules that govern homeostatic regulation of other synapse types are less understood. While cholinergic synapses have emerged as a critical component in the etiology of mammalian neurodegenerative disease mechanisms, relatively few studies have been conducted on the homeostatic plasticity of such synapses, particularly in the mammalian nervous system. An exploration of homeostatic mechanisms at the cholinergic synapse may illuminate potential therapeutic targets for disease management and treatment. We will review cholinergic homeostatic plasticity in the mammalian neuromuscular junction, the autonomic nervous system, central synapses, and in relation to pathological conditions including Alzheimer disease and DYT1 dystonia. This work provides a historical context for the field of cholinergic homeostatic regulation by examining common themes, unique features, and outstanding questions associated with these distinct cholinergic synapse types and aims to inform future research in the field.
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Creation of Neuronal Ensembles and Cell-Specific Homeostatic Plasticity through Chronic Sparse Optogenetic Stimulation. J Neurosci 2023; 43:82-92. [PMID: 36400529 PMCID: PMC9838708 DOI: 10.1523/jneurosci.1104-22.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 09/15/2022] [Accepted: 10/16/2022] [Indexed: 11/19/2022] Open
Abstract
Cortical computations emerge from the dynamics of neurons embedded in complex cortical circuits. Within these circuits, neuronal ensembles, which represent subnetworks with shared functional connectivity, emerge in an experience-dependent manner. Here we induced ensembles in ex vivo cortical circuits from mice of either sex by differentially activating subpopulations through chronic optogenetic stimulation. We observed a decrease in voltage correlation, and importantly a synaptic decoupling between the stimulated and nonstimulated populations. We also observed a decrease in firing rate during Up-states in the stimulated population. These ensemble-specific changes were accompanied by decreases in intrinsic excitability in the stimulated population, and a decrease in connectivity between stimulated and nonstimulated pyramidal neurons. By incorporating the empirically observed changes in intrinsic excitability and connectivity into a spiking neural network model, we were able to demonstrate that changes in both intrinsic excitability and connectivity accounted for the decreased firing rate, but only changes in connectivity accounted for the observed decorrelation. Our findings help ascertain the mechanisms underlying the ability of chronic patterned stimulation to create ensembles within cortical circuits and, importantly, show that while Up-states are a global network-wide phenomenon, functionally distinct ensembles can preserve their identity during Up-states through differential firing rates and correlations.SIGNIFICANCE STATEMENT The connectivity and activity patterns of local cortical circuits are shaped by experience. This experience-dependent reorganization of cortical circuits is driven by complex interactions between different local learning rules, external input, and reciprocal feedback between many distinct brain areas. Here we used an ex vivo approach to demonstrate how simple forms of chronic external stimulation can shape local cortical circuits in terms of their correlated activity and functional connectivity. The absence of feedback between different brain areas and full control of external input allowed for a tractable system to study the underlying mechanisms and development of a computational model. Results show that differential stimulation of subpopulations of neurons significantly reshapes cortical circuits and forms subnetworks referred to as neuronal ensembles.
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Theta patterns of stimulation induce synaptic and intrinsic potentiation in O-LM interneurons. Proc Natl Acad Sci U S A 2022; 119:e2205264119. [PMID: 36282913 PMCID: PMC9636972 DOI: 10.1073/pnas.2205264119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Brain oscillations have long-lasting effects on synaptic and cellular properties. For instance, synaptic stimulation at theta (θ) frequency induces persistent depression of both excitatory synaptic transmission and intrinsic excitability in CA1 principal neurons. However, the incidence of θ activity on synaptic transmission and intrinsic excitability in hippocampal GABAergic interneurons is unclear. We report here the induction of both synaptic and intrinsic potentiation in oriens-lacunosum moleculare (O-LM) interneurons following stimulation of afferent glutamatergic inputs in the θ frequency range (∼5 Hz). Long-term synaptic potentiation (LTP) is induced by synaptic activation of calcium-permeable AMPA receptors (CP-AMPAR), whereas long-term potentiation of intrinsic excitability (LTP-IE) results from the mGluR1-dependent down-regulation of Kv7 voltage-dependent potassium channel and hyperpolarization activated and cyclic nucleotide-gated (HCN) channel through the depletion of phosphatidylinositol-4,5-biphosphate (PIP2). LTP and LTP-IE are reversible, demonstrating that both synaptic and intrinsic changes are bidirectional in O-LM cells. We conclude that synaptic activity at θ frequency induces both synaptic and intrinsic potentiation in O-LM interneurons, i.e., the opposite of what is typically seen in glutamatergic neurons.
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Extrémet J, El Far O, Ankri N, Irani SR, Debanne D, Russier M. An Epitope-Specific LGI1-Autoantibody Enhances Neuronal Excitability by Modulating Kv1.1 Channel. Cells 2022; 11:cells11172713. [PMID: 36078121 PMCID: PMC9454693 DOI: 10.3390/cells11172713] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/22/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
Leucine-rich Glioma-Inactivated protein 1 (LGI1) is expressed in the central nervous system and its genetic loss of function is associated with epileptic disorders. Additionally, patients with LGI1-directed autoantibodies have frequent focal seizures as a key feature of their disease. LGI1 is composed of a Leucine-Rich Repeat (LRR) and an Epitempin (EPTP) domain. These domains are reported to interact with different members of the transsynaptic complex formed by LGI1 at excitatory synapses, including presynaptic Kv1 potassium channels. Patient-derived recombinant monoclonal antibodies (mAbs) are ideal reagents to study whether domain-specific LGI1-autoantibodies induce epileptiform activities in neurons and their downstream mechanisms. We measured the intrinsic excitability of CA3 pyramidal neurons in organotypic cultures from rat hippocampus treated with either an LRR- or an EPTP-reactive patient-derived mAb, or with IgG from control patients. We found an increase in intrinsic excitability correlated with a reduction of the sensitivity to a selective Kv1.1-channel blocker in neurons treated with the LRR mAb, but not in neurons treated with the EPTP mAb. Our findings suggest LRR mAbs are able to modulate neuronal excitability that could account for epileptiform activity observed in patients.
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Affiliation(s)
| | - Oussama El Far
- UNIS, INSERM, Aix-Marseille Université, 13015 Marseille, France
| | - Norbert Ankri
- UNIS, INSERM, Aix-Marseille Université, 13015 Marseille, France
| | - Sarosh R. Irani
- Oxford Autoimmune Neurology Group, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK
| | - Dominique Debanne
- UNIS, INSERM, Aix-Marseille Université, 13015 Marseille, France
- Correspondence: (D.D.); (M.R.)
| | - Michaël Russier
- UNIS, INSERM, Aix-Marseille Université, 13015 Marseille, France
- Correspondence: (D.D.); (M.R.)
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