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Juárez EH, Wood CR, Davies R, Kehoe O, Johnson WEB, Merighi A, Ferrini F. ST2-Conditioned Medium Fosters Dorsal Horn Cell Excitability and Synaptic Transmission in Cultured Mouse Spinal Cord. Stem Cell Rev Rep 2023; 19:2918-2928. [PMID: 37674016 PMCID: PMC10661801 DOI: 10.1007/s12015-023-10618-x] [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] [Accepted: 08/28/2023] [Indexed: 09/08/2023]
Abstract
Conditioned medium obtained from bone marrow-derived stem cells has been proposed as a novel cell-free therapy in spinal cord injury and neuropathic pain, yet the direct effect on spinal neuron function has never been investigated. Here, we adopted spinal cord organotypic cultures (SCOCs) as an experimental model to probe the effect of ST2 murine mesenchymal stem cells-conditioned medium (ST2-CM) on dorsal horn (DH) neuron functional properties. Three days of SCOC exposure to ST2-CM increased neuronal activity measured by Fos expression, as well as spontaneous or induced firing. We showed that the increase in neuronal excitability was associated with changes in both intrinsic membrane properties and an enhanced excitatory drive. The increased excitability at the single-cell level was substantiated at the network level by detecting synchronous bursts of calcium waves across DH neurons. Altogether, SCOCs represent a viable tool to probe mesenchymal cells' effect on intact neuronal networks. Our findings indicate that ST2-CM enhances neuronal activity and synaptic wiring in the spinal dorsal horn. Our data also support the trophic role of mesenchymal cells CM in maintaining network activity in spinal circuits.
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Affiliation(s)
- Esri H Juárez
- Department of Veterinary Sciences, University of Turin, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy
| | - Chelsea R Wood
- Chester Medical School, University of Chester, Parkgate Road, Chester, CH1 4BJ, UK
- School of Life Sciences, Coventry University, Coventry, CV1 2DS, UK
| | - Rebecca Davies
- Centre for Regenerative Medicine Research, School of Medicine, Keele University, Keele, Staffordshire, ST5 5BG, UK
- Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, SY10 7AG, UK
| | - Oksana Kehoe
- Centre for Regenerative Medicine Research, School of Medicine, Keele University, Keele, Staffordshire, ST5 5BG, UK
- Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, SY10 7AG, UK
| | - William E B Johnson
- Chester Medical School, University of Chester, Parkgate Road, Chester, CH1 4BJ, UK
| | - Adalberto Merighi
- Department of Veterinary Sciences, University of Turin, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy
| | - Francesco Ferrini
- Department of Veterinary Sciences, University of Turin, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy.
- Department of Psychiatry and Neuroscience, Université Laval, Québec, G1K 7P4, Canada.
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2
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Cortés-Llanos B, Rauti R, Ayuso-Sacido Á, Pérez L, Ballerini L. Impact of Magnetite Nanowires on In Vitro Hippocampal Neural Networks. Biomolecules 2023; 13:biom13050783. [PMID: 37238653 DOI: 10.3390/biom13050783] [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: 03/16/2023] [Revised: 04/20/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
Nanomaterials design, synthesis, and characterization are ever-expanding approaches toward developing biodevices or neural interfaces to treat neurological diseases. The ability of nanomaterials features to tune neuronal networks' morphology or functionality is still under study. In this work, we unveil how interfacing mammalian brain cultured neurons and iron oxide nanowires' (NWs) orientation affect neuronal and glial densities and network activity. Iron oxide NWs were synthesized by electrodeposition, fixing the diameter to 100 nm and the length to 1 µm. Scanning electron microscopy, Raman, and contact angle measurements were performed to characterize the NWs' morphology, chemical composition, and hydrophilicity. Hippocampal cultures were seeded on NWs devices, and after 14 days, the cell morphology was studied by immunocytochemistry and confocal microscopy. Live calcium imaging was performed to study neuronal activity. Using random nanowires (R-NWs), higher neuronal and glial cell densities were obtained compared with the control and vertical nanowires (V-NWs), while using V-NWs, more stellate glial cells were found. R-NWs produced a reduction in neuronal activity, while V-NWs increased the neuronal network activity, possibly due to a higher neuronal maturity and a lower number of GABAergic neurons, respectively. These results highlight the potential of NWs manipulations to design ad hoc regenerative interfaces.
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Affiliation(s)
- Belén Cortés-Llanos
- Departamento de Física de Materiales, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Fundación IMDEA Nanociencia, C/Faraday 9, 28049 Madrid, Spain
- Department of Medicine, Duke University, Durham, NC 27705, USA
| | - Rossana Rauti
- International School for Advanced Studies (ISAS-SISSA), 34136 Trieste, Italy
- Deparment of Biomolecular Sciences, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy
| | - Ángel Ayuso-Sacido
- Brain Tumor Laboratory, Fundación Vithas, Grupo Hospitales Vithas, 28043 Madrid, Spain
- Faculty of Experimental Science and Faculty of Medicine, University of Francisco de Vitoria, 28223 Madrid, Spain
| | - Lucas Pérez
- Departamento de Física de Materiales, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Fundación IMDEA Nanociencia, C/Faraday 9, 28049 Madrid, Spain
| | - Laura Ballerini
- International School for Advanced Studies (ISAS-SISSA), 34136 Trieste, Italy
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3
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Di Mauro G, Amoriello R, Lozano N, Carnasciali A, Guasti D, Becucci M, Cellot G, Kostarelos K, Ballerini C, Ballerini L. Graphene Oxide Nanosheets Reduce Astrocyte Reactivity to Inflammation and Ameliorate Experimental Autoimmune Encephalomyelitis. ACS NANO 2023; 17:1965-1978. [PMID: 36692902 PMCID: PMC9933621 DOI: 10.1021/acsnano.2c06609] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
In neuroinflammation, astrocytes play multifaceted roles that regulate the neuronal environment. Astrocytes sense and respond to pro-inflammatory cytokines (CKs) and, by a repertoire of intracellular Ca2+ signaling, contribute to disease progression. Therapeutic approaches wish to reduce the overactivation in Ca2+ signaling in inflammatory-reactive astrocytes to restore dysregulated cellular changes. Cell-targeting therapeutics might take advantage by the use of nanomaterial-multifunctional platforms such as graphene oxide (GO). GO biomedical applications in the nervous system involve therapeutic delivery and sensing, and GO flakes were shown to enable interfacing of neuronal and glial membrane dynamics. We exploit organotypic spinal cord cultures and optical imaging to explore Ca2+ changes in astrocytes, and we report, when spinal tissue is exposed to CKs, neuroinflammatory-associated modulation of resident glia. We show the efficacy of GO to revert these dynamic changes in astrocytic reactivity to CKs, and we translate this potential in an animal model of immune-mediated neuroinflammatory disease.
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Affiliation(s)
- Giuseppe Di Mauro
- International
School for Advanced Studies (SISSA/ISAS), 34136Trieste, Italy
| | - Roberta Amoriello
- International
School for Advanced Studies (SISSA/ISAS), 34136Trieste, Italy
- Dipartimento
di Medicina Sperimentale e Clinica, University
of Florence, 50139Florence, Italy
| | - Neus Lozano
- Catalan
Institute of Nanoscience and Nanotechnology (ICN2), 08193Barcelona, Spain
| | - Alberto Carnasciali
- Dipartimento
di Medicina Sperimentale e Clinica, University
of Florence, 50139Florence, Italy
| | - Daniele Guasti
- Dipartimento
di Medicina Sperimentale e Clinica, University
of Florence, 50139Florence, Italy
| | - Maurizio Becucci
- Dipartimento
di Chimica “Ugo Schiff”, DICUS, University of Florence, 50139Florence, Italy
| | - Giada Cellot
- International
School for Advanced Studies (SISSA/ISAS), 34136Trieste, Italy
| | - Kostas Kostarelos
- Catalan
Institute of Nanoscience and Nanotechnology (ICN2), 08193Barcelona, Spain
- Nanomedicine
Lab, and Faculty of Biology, Medicine & Health, The National Graphene
Institute, University of Manchester, ManchesterM13 9PL, United Kingdom
| | - Clara Ballerini
- Dipartimento
di Medicina Sperimentale e Clinica, University
of Florence, 50139Florence, Italy
| | - Laura Ballerini
- International
School for Advanced Studies (SISSA/ISAS), 34136Trieste, Italy
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4
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Panattoni G, Amoriello R, Memo C, Thalhammer A, Ballerini C, Ballerini L. Diverse inflammatory threats modulate astrocytes Ca 2+ signaling via connexin43 hemichannels in organotypic spinal slices. Mol Brain 2021; 14:159. [PMID: 34696792 PMCID: PMC8547100 DOI: 10.1186/s13041-021-00868-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/15/2021] [Indexed: 02/07/2023] Open
Abstract
Neuroinflammation is an escalation factor shared by a vast range of central nervous system (CNS) pathologies, from neurodegenerative diseases to neuropsychiatric disorders. CNS immune status emerges by the integration of the responses of resident and not resident cells, leading to alterations in neural circuits functions. To explore spinal cord astrocyte reactivity to inflammatory threats we focused our study on the effects of local inflammation in a controlled micro-environment, the organotypic spinal slices, developed from the spinal cord of mouse embryos. These organ cultures represent a complex in vitro model where sensory-motor cytoarchitecture, synaptic properties and spinal cord resident cells, are retained in a 3D fashion and we recently exploit these cultures to model two diverse immune conditions in the CNS, involving different inflammatory networks and products. Here, we specifically focus on the tuning of calcium signaling in astrocytes by these diverse types of inflammation and we investigate the mechanisms which modulate intracellular calcium release and its spreading among astrocytes in the inflamed environment. Organotypic spinal cord slices are cultured for two or three weeks in vitro (WIV) and exposed for 6 h to a cocktail of cytokines (CKs), composed by tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1 β) and granulocyte macrophage-colony stimulating factor (GM-CSF), or to lipopolysaccharide (LPS). By live calcium imaging of the ventral horn, we document an increase in active astrocytes and in the occurrence of spontaneous calcium oscillations displayed by these cells when exposed to each inflammatory threat. Through several pharmacological treatments, we demonstrate that intracellular calcium sources and the activation of connexin 43 (Cx43) hemichannels have a pivotal role in increasing calcium intercellular communication in both CKs and LPS conditions, while the Cx43 gap junction communication is apparently reduced by the inflammatory treatments.
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Affiliation(s)
- Giulia Panattoni
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy
| | - Roberta Amoriello
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy.,Dipartimento di Medicina Sperimentale e Clinica, University of Florence, 50139, Florence, Italy
| | - Christian Memo
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy
| | - Agnes Thalhammer
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy
| | - Clara Ballerini
- Dipartimento di Medicina Sperimentale e Clinica, University of Florence, 50139, Florence, Italy.
| | - Laura Ballerini
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy.
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5
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Chronic BDNF simultaneously inhibits and unmasks superficial dorsal horn neuronal activity. Sci Rep 2021; 11:2249. [PMID: 33500423 PMCID: PMC7838274 DOI: 10.1038/s41598-021-81269-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/04/2021] [Indexed: 11/12/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is critically involved in the pathophysiology of chronic pain. However, the mechanisms of BDNF action on specific neuronal populations in the spinal superficial dorsal horn (SDH) requires further study. We used chronic BDNF treatment (200 ng/ml, 5–6 days) of defined-medium, serum-free spinal organotypic cultures to study intracellular calcium ([Ca2+]i) fluctuations. A detailed quantitative analysis of these fluctuations using the Frequency-independent biological signal identification (FIBSI) program revealed that BDNF simultaneously depressed activity in some SDH neurons while it unmasked a particular subpopulation of ‘silent’ neurons causing them to become spontaneously active. Blockade of gap junctions disinhibited a subpopulation of SDH neurons and reduced BDNF-induced synchrony in BDNF-treated cultures. BDNF reduced neuronal excitability assessed by measuring spontaneous excitatory postsynaptic currents. This was similar to the depressive effect of BDNF on the [Ca2+]i fluctuations. This study reveals novel regulatory mechanisms of SDH neuronal excitability in response to BDNF.
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6
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Saternos H, Ley S, AbouAlaiwi W. Primary Cilia and Calcium Signaling Interactions. Int J Mol Sci 2020; 21:E7109. [PMID: 32993148 PMCID: PMC7583801 DOI: 10.3390/ijms21197109] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 02/06/2023] Open
Abstract
The calcium ion (Ca2+) is a diverse secondary messenger with a near-ubiquitous role in a vast array of cellular processes. Cilia are present on nearly every cell type in either a motile or non-motile form; motile cilia generate fluid flow needed for a variety of biological processes, such as left-right body patterning during development, while non-motile cilia serve as the signaling powerhouses of the cell, with vital singling receptors localized to their ciliary membranes. Much of the research currently available on Ca2+-dependent cellular actions and primary cilia are tissue-specific processes. However, basic stimuli-sensing pathways, such as mechanosensation, chemosensation, and electrical sensation (electrosensation), are complex processes entangled in many intersecting pathways; an overview of proposed functions involving cilia and Ca2+ interplay will be briefly summarized here. Next, we will focus on summarizing the evidence for their interactions in basic cellular activities, including the cell cycle, cell polarity and migration, neuronal pattering, glucose-mediated insulin secretion, biliary regulation, and bone formation. Literature investigating the role of cilia and Ca2+-dependent processes at a single-cellular level appears to be scarce, though overlapping signaling pathways imply that cilia and Ca2+ interact with each other on this level in widespread and varied ways on a perpetual basis. Vastly different cellular functions across many different cell types depend on context-specific Ca2+ and cilia interactions to trigger the correct physiological responses, and abnormalities in these interactions, whether at the tissue or the single-cell level, can result in diseases known as ciliopathies; due to their clinical relevance, pathological alterations of cilia function and Ca2+ signaling will also be briefly touched upon throughout this review.
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Affiliation(s)
| | | | - Wissam AbouAlaiwi
- Department of Pharmacology and Experimental Therapeutics, University of Toledo Health Science Campus, Toledo, OH 43614, USA; (H.S.); (S.L.)
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7
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Buntschu S, Tscherter A, Heidemann M, Streit J. Critical Components for Spontaneous Activity and Rhythm Generation in Spinal Cord Circuits in Culture. Front Cell Neurosci 2020; 14:81. [PMID: 32410961 PMCID: PMC7198714 DOI: 10.3389/fncel.2020.00081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/19/2020] [Indexed: 11/23/2022] Open
Abstract
Neuronal excitability contributes to rhythm generation in central pattern generating networks (CPGs). In spinal cord CPGs, such intrinsic excitability partly relies on persistent sodium currents (INaP), whereas respiratory CPGs additionally depend on calcium-activated cation currents (ICAN). Here, we investigated the contributions of INaP and ICAN to spontaneous rhythm generation in neuronal networks of the spinal cord and whether they mainly involve Hb9 neurons. We used cultures of ventral and transverse slices from the E13–14 embryonic rodent lumbar spinal cord on multielectrode arrays (MEAs). All cultures showed spontaneous bursts of network activity. Blocking synaptic excitation with the AMPA receptor antagonist CNQX suppressed spontaneous network bursts and left asynchronous intrinsic activity at about 30% of the electrodes. Such intrinsic activity was completely blocked at all electrodes by both the INaP blocker riluzole as well as by the ICAN blocker flufenamic acid (FFA) and the more specific TRPM4 channel antagonist 9-phenanthrol. All three antagonists also suppressed spontaneous bursting completely and strongly reduced stimulus-evoked bursts. Also, FFA reduced repetitive spiking that was induced in single neurons by injection of depolarizing current pulses to few spikes. Other antagonists of unspecific cation currents or calcium currents had no suppressing effects on either intrinsic activity (gadolinium chloride) or spontaneous bursting (the TRPC channel antagonists clemizole and ML204 and the T channel antagonist TTA-P2). Combined patch-clamp and MEA recordings showed that Hb9 interneurons were activated by network bursts but could not initiate them. Together these findings suggest that both INaP through Na+-channels and ICAN through putative TRPM4 channels contribute to spontaneous intrinsic and repetitive spiking in spinal cord neurons and thereby to the generation of network bursts.
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Affiliation(s)
- Samuel Buntschu
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Anne Tscherter
- Department of Physiology, University of Bern, Bern, Switzerland
| | | | - Jürg Streit
- Department of Physiology, University of Bern, Bern, Switzerland
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8
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Bilirubin disrupts calcium homeostasis in neonatal hippocampal neurons: a new pathway of neurotoxicity. Arch Toxicol 2020; 94:845-855. [DOI: 10.1007/s00204-020-02659-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/03/2020] [Indexed: 12/22/2022]
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9
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Rauti R, Secomandi N, Martín C, Bosi S, Severino FPU, Scaini D, Prato M, Vázquez E, Ballerini L. Tuning Neuronal Circuit Formation in 3D Polymeric Scaffolds by Introducing Graphene at the Bio/Material Interface. ACTA ACUST UNITED AC 2020; 4:e1900233. [DOI: 10.1002/adbi.201900233] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/19/2020] [Indexed: 12/17/2022]
Affiliation(s)
- Rossana Rauti
- International School for Advanced Studies (SISSA/ISAS) Trieste 34136 Italy
| | - Nicola Secomandi
- International School for Advanced Studies (SISSA/ISAS) Trieste 34136 Italy
- Instituto Regional de Investigación Científica Aplicada (IRICA) Universidad de Castilla‐La Mancha Avda Camilo José Cela 13071 Ciudad Real Spain
| | - Cristina Martín
- Department of Chemical and Pharmaceutical Sciences Università degli Studi di Trieste Via Licio Giorgieri 1 Trieste 34127 Italy
- Carbon Bionanotechnology Group CIC biomaGUNE Paseo Miramón 182 San Sebastián 20014 Guipúzcoa Spain
| | - Susanna Bosi
- Carbon Bionanotechnology Group CIC biomaGUNE Paseo Miramón 182 San Sebastián 20014 Guipúzcoa Spain
| | | | - Denis Scaini
- International School for Advanced Studies (SISSA/ISAS) Trieste 34136 Italy
- Basque Foundation for Science Ikerbasque Bilbao 48013 Spain
| | - Maurizio Prato
- Carbon Bionanotechnology Group CIC biomaGUNE Paseo Miramón 182 San Sebastián 20014 Guipúzcoa Spain
- Faculty of Chemical Science and Technology Universidad de Castilla‐La Mancha 13071 Ciudad Real Spain
| | - Ester Vázquez
- Department of Chemical and Pharmaceutical Sciences Università degli Studi di Trieste Via Licio Giorgieri 1 Trieste 34127 Italy
| | - Laura Ballerini
- International School for Advanced Studies (SISSA/ISAS) Trieste 34136 Italy
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10
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Barrejón M, Rauti R, Ballerini L, Prato M. Chemically Cross-Linked Carbon Nanotube Films Engineered to Control Neuronal Signaling. ACS NANO 2019; 13:8879-8889. [PMID: 31329426 DOI: 10.1021/acsnano.9b02429] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In recent years, the use of free-standing carbon nanotube (CNT) films for neural tissue engineering has attracted tremendous attention. CNT films show large surface area and high electrical conductivity that combined with flexibility and biocompatibility may promote neuron growth and differentiation while stimulating neural activity. In addition, adhesion, survival, and growth of neurons can be modulated through chemical modification of CNTs. Axonal and synaptic signaling can also be positively tuned by these materials. Here we describe the ability of free-standing CNT films to influence neuronal activity. We demonstrate that the degree of cross-linking between the CNTs has a strong impact on the electrical conductivity of the substrate, which, in turn, regulates neural circuit outputs.
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Affiliation(s)
- Myriam Barrejón
- Department of Chemical and Pharmaceutical Sciences , Università degli Studi di Trieste , Via Licio Giorgieri 1 , Trieste 34127 , Italy
| | - Rossana Rauti
- International School for Advanced Studies (SISSA/ISAS) , Trieste 34136 , Italy
| | - Laura Ballerini
- International School for Advanced Studies (SISSA/ISAS) , Trieste 34136 , Italy
| | - Maurizio Prato
- Department of Chemical and Pharmaceutical Sciences , Università degli Studi di Trieste , Via Licio Giorgieri 1 , Trieste 34127 , Italy
- Carbon Bionanotechnology Group , CIC biomaGUNE , Paseo Miramón 182, San Sebastián , Guipúzcoa 20014 , Spain
- Basque Foundation for Science , Ikerbasque, Bilbao 48013 , Spain
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11
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Musto M, Rauti R, Rodrigues AF, Bonechi E, Ballerini C, Kostarelos K, Ballerini L. 3D Organotypic Spinal Cultures: Exploring Neuron and Neuroglia Responses Upon Prolonged Exposure to Graphene Oxide. Front Syst Neurosci 2019; 13:1. [PMID: 30733671 PMCID: PMC6354065 DOI: 10.3389/fnsys.2019.00001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 01/03/2019] [Indexed: 11/13/2022] Open
Abstract
Graphene-based nanomaterials are increasingly engineered as components of biosensors, interfaces or drug delivery platforms in neuro-repair strategies. In these developments, the mostly used derivative of graphene is graphene oxide (GO). To tailor the safe development of GO nanosheets, we need to model in vitro tissue responses, and in particular the reactivity of microglia, a sub-population of neuroglia that acts as the first active immune response, when challenged by GO. Here, we investigated central nervous system (CNS) tissue reactivity upon long-term exposure to GO nanosheets in 3D culture models. We used the mouse organotypic spinal cord cultures, ideally suited for studying long-term interference with cues delivered at controlled times and concentrations. In cultured spinal segments, the normal presence, distribution and maturation of anatomically distinct classes of neurons and resident neuroglial cells are preserved. Organotypic explants were developed for 2 weeks embedded in fibrin glue alone or presenting GO nanosheets at 10, 25 and 50 μg/mL. We addressed the impact of such treatments on premotor synaptic activity monitored by patch clamp recordings of ventral interneurons. We investigated by immunofluorescence and confocal microscopy the accompanying glial responses to GO exposure, focusing on resident microglia, tested in organotypic spinal slices and in isolated neuroglia cultures. Our results suggest that microglia reactivity to accumulation of GO flakes, maybe due to active phagocytosis, may trim down synaptic activity, although in the absence of an effective activation of inflammatory response and in the absence of neuronal cell death.
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Affiliation(s)
- Mattia Musto
- Neuron Physiology and Technology Lab, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Rossana Rauti
- Neuron Physiology and Technology Lab, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Artur Filipe Rodrigues
- Nanomedicine Lab, Faculty of Biology, Medicine & Health and National Graphene Institute, University of Manchester, Manchester, United Kingdom
| | - Elena Bonechi
- Department NEUROFARBA, University of Florence, Florence, Italy
| | - Clara Ballerini
- Laboratory of Neuroimmunology, Dipartimento di Medicina Sperimentale e Clinica, University of Firenze, Firenze, Italy
| | - Kostas Kostarelos
- Nanomedicine Lab, Faculty of Biology, Medicine & Health and National Graphene Institute, University of Manchester, Manchester, United Kingdom
| | - Laura Ballerini
- Neuron Physiology and Technology Lab, International School for Advanced Studies (SISSA), Trieste, Italy
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12
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Kaur J, Rauti R, Nistri A. Nicotine‐mediated neuroprotection of rat spinal networks against excitotoxicity. Eur J Neurosci 2018; 47:1353-1374. [DOI: 10.1111/ejn.13950] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 03/19/2018] [Accepted: 04/10/2018] [Indexed: 12/16/2022]
Affiliation(s)
- Jaspreet Kaur
- Department of NeuroscienceInternational School for Advanced Studies (SISSA) Trieste Italy
- Jaspreet Kaur, Institute of Neurosciences of Timone (IMAPATH Team) ‐ CERIMEDUMR 7289Aix‐Marseille University 27, boulevard Jean Moulin Marseille Cedex 05 13385 France
| | - Rossana Rauti
- Department of NeuroscienceInternational School for Advanced Studies (SISSA) Trieste Italy
| | - Andrea Nistri
- Department of NeuroscienceInternational School for Advanced Studies (SISSA) Trieste Italy
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13
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Boakye PA, Schmidt EKA, Rancic V, Kerr B, Ballanyi K, Smith PA. Characterization of Superficial Dorsal Horn Neurons from "Tamamaki" Mice and Stability of their GAD67-EGFP Phenotype in Defined-Medium Organotypic Culture. Neuroscience 2017; 372:126-140. [PMID: 29294339 DOI: 10.1016/j.neuroscience.2017.12.047] [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: 09/08/2017] [Revised: 12/19/2017] [Accepted: 12/26/2017] [Indexed: 12/12/2022]
Abstract
Defined medium organotypic cultures (DMOTC) containing spinal dorsal horn neurons are especially useful in studying the etiology and pharmacology of chronic pain. We made whole-cell recordings from neurons in acutely isolated mouse spinal cord slices or from those maintained in DMOTC for up to 6 weeks. In acute slices, neurons in the substantia gelatinosa exhibited 7 different firing patterns in response to 800-ms depolarizing current commands; delay (irregular), delay (tonic), tonic, regular firing, phasic, initial bursting and single spiking. Initial bursting and regular firing neurons are not found in rat substantia gelatinosa. In acute slices from "Tamamaki" mice that express enhanced green fluorescent protein (EGFP) under the control of the glutamic acid decarboxylase 67 (GAD67) promotor, tonic, phasic and regular firing neurons exhibited the strongest GABAergic (GAD67-EGFP+) phenotype. Delay (tonic) and delay (irregular) neurons almost never expressed GAD67 (GAD67-EGFP-) and are likely glutamatergic. All seven phenotypes were preserved in mouse spinal cord neurons in DMOTC prepared from e12 embryos and the GAD67-EGFP+ phenotype continued to associate with phasic and regular firing neurons. Only 3 out of 51 GAD67-EGFP+ neurons exhibited a delay (tonic) firing pattern. Modifications to the mouse genome thus continue to be expressed when embryonic neurons develop in vitro in DMOTC. However, analysis of the amplitude and interevent interval of spontaneous EPSCs (sEPSCs) indicated substantial re-arrangement of synaptic connections within the cultures. Despite this, the characteristics and age-dependence of asynchronous oscillatory activity, as monitored by multiphoton Ca2+ imaging, were similar in acute slices and in DMOTC.
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Affiliation(s)
- Paul A Boakye
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton T6G 2H7, AB, Canada
| | - Emma K A Schmidt
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton T6G 2H7, AB, Canada
| | - Vladimir Rancic
- Department of Physiology, University of Alberta, Edmonton T6G 2H7, AB, Canada
| | - Bradley Kerr
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton T6G 2H7, AB, Canada; Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton T6G 2H7, AB, Canada; Department of Pharmacology, University of Alberta, Edmonton T6G 2H7, AB, Canada
| | - Klaus Ballanyi
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton T6G 2H7, AB, Canada; Department of Physiology, University of Alberta, Edmonton T6G 2H7, AB, Canada
| | - Peter A Smith
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton T6G 2H7, AB, Canada; Department of Pharmacology, University of Alberta, Edmonton T6G 2H7, AB, Canada.
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Comparative Analysis of Spontaneous and Stimulus-Evoked Calcium Transients in Proliferating and Differentiating Human Midbrain-Derived Stem Cells. Stem Cells Int 2017; 2017:9605432. [PMID: 29201062 PMCID: PMC5671755 DOI: 10.1155/2017/9605432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 09/10/2017] [Indexed: 12/24/2022] Open
Abstract
Spontaneous cytosolic calcium transients and oscillations have been reported in various tissues of nonhuman and human origin but not in human midbrain-derived stem cells. Using confocal microfluorimetry, we studied spontaneous calcium transients and calcium-regulating mechanisms in a human ventral mesencephalic stem cell line undergoing proliferation and neuronal differentiation. Spontaneous calcium transients were detected in a large fraction of both proliferating (>50%) and differentiating (>55%) cells. We provide evidence for the existence of intracellular calcium stores that respond to muscarinic activation of the cells, having sensitivity for ryanodine and thapsigargin possibly reflecting IP3 receptor activity and the presence of ryanodine receptors and calcium ATPase pumps. The observed calcium transient activity potentially supports the existence of a sodium-calcium antiporter and the existence of calcium influx induced by depletion of calcium stores. We conclude that the cells have developed the most important mechanisms governing cytosolic calcium homeostasis. This is the first comparative report of spontaneous calcium transients in proliferating and differentiating human midbrain-derived stem cells that provides evidence for the mechanisms that are likely to be involved. We propose that the observed spontaneous calcium transients may contribute to mechanisms involved in cell proliferation, phenotypic differentiation, and general cell maturation.
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15
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Rauti R, Lozano N, León V, Scaini D, Musto M, Rago I, Ulloa Severino FP, Fabbro A, Casalis L, Vázquez E, Kostarelos K, Prato M, Ballerini L. Graphene Oxide Nanosheets Reshape Synaptic Function in Cultured Brain Networks. ACS NANO 2016; 10:4459-71. [PMID: 27030936 DOI: 10.1021/acsnano.6b00130] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Graphene offers promising advantages for biomedical applications. However, adoption of graphene technology in biomedicine also poses important challenges in terms of understanding cell responses, cellular uptake, or the intracellular fate of soluble graphene derivatives. In the biological microenvironment, graphene nanosheets might interact with exposed cellular and subcellular structures, resulting in unexpected regulation of sophisticated biological signaling. More broadly, biomedical devices based on the design of these 2D planar nanostructures for interventions in the central nervous system require an accurate understanding of their interactions with the neuronal milieu. Here, we describe the ability of graphene oxide nanosheets to down-regulate neuronal signaling without affecting cell viability.
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Affiliation(s)
- Rossana Rauti
- Life Science Department, University of Trieste , 34127 Trieste, Italy
| | - Neus Lozano
- Nanomedicine Lab, School of Medicine and National Graphene Institute, Faculty of Medical & Human Sciences, University of Manchester , M13 9PL Manchester, United Kingdom
| | - Veronica León
- Departamento de Química Orgánica, Facultad de Ciencias y Tecnologías Químicas-IRICA, Universidad de Castilla La Mancha , 13071 Ciudad Real, Spain
| | - Denis Scaini
- Life Science Department, University of Trieste , 34127 Trieste, Italy
- ELETTRA Synchrotron Light Source , 34149 Trieste, Italy
| | - Mattia Musto
- International School for Advanced Studies (SISSA) , 34136 Trieste, Italy
| | - Ilaria Rago
- ELETTRA Synchrotron Light Source , 34149 Trieste, Italy
| | | | - Alessandra Fabbro
- Department of Chemical and Pharmaceutical Sciences, University of Trieste , 34127 Trieste, Italy
| | | | - Ester Vázquez
- Departamento de Química Orgánica, Facultad de Ciencias y Tecnologías Químicas-IRICA, Universidad de Castilla La Mancha , 13071 Ciudad Real, Spain
| | - Kostas Kostarelos
- Nanomedicine Lab, School of Medicine and National Graphene Institute, Faculty of Medical & Human Sciences, University of Manchester , M13 9PL Manchester, United Kingdom
| | - Maurizio Prato
- Department of Chemical and Pharmaceutical Sciences, University of Trieste , 34127 Trieste, Italy
- CIC BiomaGUNE, Parque Tecnológico de San Sebastián, Paseo Miramón, 182, 20009 San Sebastián, Guipúzcoa, Spain
- Basque Foundation for Science , Ikerbasque, Bilbao 48013, Spain
| | - Laura Ballerini
- Life Science Department, University of Trieste , 34127 Trieste, Italy
- International School for Advanced Studies (SISSA) , 34136 Trieste, Italy
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16
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From 2D to 3D: novel nanostructured scaffolds to investigate signalling in reconstructed neuronal networks. Sci Rep 2015; 5:9562. [PMID: 25910072 PMCID: PMC5407555 DOI: 10.1038/srep09562] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 03/10/2015] [Indexed: 12/21/2022] Open
Abstract
To recreate in vitro 3D neuronal circuits will ultimately increase the relevance of results from cultured to whole-brain networks and will promote enabling technologies for neuro-engineering applications. Here we fabricate novel elastomeric scaffolds able to instruct 3D growth of living primary neurons. Such systems allow investigating the emerging activity, in terms of calcium signals, of small clusters of neurons as a function of the interplay between the 2D or 3D architectures and network dynamics. We report the ability of 3D geometry to improve functional organization and synchronization in small neuronal assemblies. We propose a mathematical modelling of network dynamics that supports such a result. Entrapping carbon nanotubes in the scaffolds remarkably boosted synaptic activity, thus allowing for the first time to exploit nanomaterial/cell interfacing in 3D growth support. Our 3D system represents a simple and reliable construct, able to improve the complexity of current tissue culture models.
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17
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Smith PA. BDNF: No gain without pain? Neuroscience 2014; 283:107-23. [DOI: 10.1016/j.neuroscience.2014.05.044] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/16/2014] [Accepted: 05/21/2014] [Indexed: 12/22/2022]
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18
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Cifra A, Mazzone GL, Nani F, Nistri A, Mladinic M. Postnatal developmental profile of neurons and glia in motor nuclei of the brainstem and spinal cord, and its comparison with organotypic slice cultures. Dev Neurobiol 2012; 72:1140-60. [PMID: 22021114 DOI: 10.1002/dneu.20991] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 10/18/2011] [Indexed: 01/31/2023]
Abstract
In vitro preparations of the neonatal rat spinal cord or brainstem are useful to investigate the organization of motor networks and their dysfunction in neurological disease models. Long-term spinal cord organotypic cultures can extend our understanding of such pathophysiological processes over longer times. It is, however, surprising that detailed descriptions of the type (and number) of neurons and glia in such preparations are currently unavailable to evaluate cell-selectivity of experimental damage. The focus of the present immunohistochemical study is the novel characterization of the cell population in the lumbar locomotor region of the rat spinal cord and in the brainstem motor nucleus hypoglossus at 0-4 postnatal days, and its comparison with spinal organotypic cultures at 2-22 days in vitro. In the nucleus hypoglossus, neurons were 40% of all cells and 80% of these were motoneurons. Astrocytes (35% of total cells) were the main glial cells, while microglia was <10%. In the spinal gray matter, the highest neuronal density was in the dorsal horn (>80%) and the lowest in the ventral horn (≤57%) with inverse astroglia numbers and few microglia. The number of neurons (including motoneurons) and astrocytes was stable after birth. Like in the spinal cord, motoneurons in organotypic spinal culture were <10% of ventral horn cells, with neurons <40%, and the rest made up by glia. The present report indicates a comparable degree of neuronal and glial maturation in brainstem and spinal motor nuclei, and that this condition is also observed in 3-week-old organotypic cultures.
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Affiliation(s)
- Alessandra Cifra
- Neurobiology Sector and IIT Unit, International School for Advanced Studies (SISSA), Trieste, Italy
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19
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Sibilla S, Fabbro A, Grandolfo M, D'Andrea P, Nistri A, Ballerini L. The patterns of spontaneous Ca2+ signals generated by ventral spinal neurons in vitro show time-dependent refinement. Eur J Neurosci 2009; 29:1543-59. [PMID: 19419420 DOI: 10.1111/j.1460-9568.2009.06708.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Embryonic spinal neurons maintained in organotypic slice culture are known to mimic certain maturation-dependent signalling changes. With such a model we investigated, in embryonic mouse spinal segments, the age-dependent spatio-temporal control of intracellular Ca(2+) signalling generated by neuronal populations in ventral circuits and its relation with electrical activity. We used Ca(2+) imaging to monitor areas located within the ventral spinal horn at 1 and 2 weeks of in vitro growth. Primitive patterns of spontaneous neuronal Ca(2+) transients (detected at 1 week) were typically synchronous. Remarkably, such transients originated from widespread propagating waves that became organized into large-scale rhythmic bursts. These activities were associated with the generation of synaptically mediated inward currents under whole-cell patch-clamp. Such patterns disappeared during longer culture of spinal segments: at 2 weeks in culture, only a subset of ventral neurons displayed spontaneous, asynchronous and repetitive Ca(2+) oscillations dissociated from background synaptic activity. We observed that the emergence of oscillations was a restricted phenomenon arising together with the transformation of ventral network electrophysiological bursting into asynchronous synaptic discharges. This change was accompanied by the appearance of discrete calbindin immunoreactivity against an unchanged background of calretinin-positive cells. It is attractive to assume that periodic oscillations of Ca(2+) confer a summative ability to these cells to shape the plasticity of local circuits through different changes (phasic or tonic) in intracellular Ca(2+).
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Affiliation(s)
- Sara Sibilla
- Physiology and Pathology Department, Centre for Neuroscience BRAIN, University of Trieste, via Fleming 22, 34127 Trieste, Italy
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20
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Sibilla S, Ballerini L. GABAergic and glycinergic interneuron expression during spinal cord development: dynamic interplay between inhibition and excitation in the control of ventral network outputs. Prog Neurobiol 2009; 89:46-60. [PMID: 19539686 DOI: 10.1016/j.pneurobio.2009.06.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 04/10/2009] [Accepted: 06/09/2009] [Indexed: 11/28/2022]
Abstract
A key objective of neuroscience research is to understand the processes leading to mature neural circuitries in the central nervous system (CNS) that enable the control of different behaviours. During development, network-constitutive neurons undergo dramatic rearrangements, involving their intrinsic properties, such as the blend of ion channels governing their firing activity, and their synaptic interactions. The spinal cord is no exception to this rule; in fact, in the ventral horn the maturation of motor networks into functional circuits is a complex process where several mechanisms cooperate to achieve the development of motor control. Elucidating such a process is crucial in identifying neurons more vulnerable to degenerative or traumatic diseases or in developing new strategies aimed at rebuilding damaged tissue. The focus of this review is on recent advances in understanding the spatio-temporal expression of the glycinergic/GABAergic system and on the contribution of this system to early network function and to motor pattern transformation along with spinal maturation. During antenatal development, the operation of mammalian spinal networks strongly depends on the activity of glycinergic/GABAergic neurons, whose action is often excitatory until shortly before birth when locomotor networks acquire the ability to generate alternating motor commands between flexor and extensor motor neurons. At this late stage of prenatal development, GABA-mediated excitation is replaced by synaptic inhibition mediated by glycine and/or GABA. At this stage of spinal maturation, the large majority of GABAergic neurons are located in the dorsal horn. We propose that elucidating the role of inhibitory systems in development will improve our knowledge on the processes regulating spinal cord maturation.
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Affiliation(s)
- Sara Sibilla
- Life Science Department, Center for Neuroscience B.R.A.I.N., University of Trieste, via Fleming 22, 34127 Trieste, Italy
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21
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Nicolau SM, de Diego AMG, Cortés L, Egea J, González JC, Mosquera M, López MG, Hernández-Guijo JM, García AG. Mitochondrial Na+/Ca2+-Exchanger Blocker CGP37157 Protects against Chromaffin Cell Death Elicited by Veratridine. J Pharmacol Exp Ther 2009; 330:844-54. [DOI: 10.1124/jpet.109.154765] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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22
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23
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Castaldo P, Cataldi M, Magi S, Lariccia V, Arcangeli S, Amoroso S. Role of the mitochondrial sodium/calcium exchanger in neuronal physiology and in the pathogenesis of neurological diseases. Prog Neurobiol 2008; 87:58-79. [PMID: 18952141 DOI: 10.1016/j.pneurobio.2008.09.017] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Revised: 09/23/2008] [Accepted: 09/29/2008] [Indexed: 11/26/2022]
Abstract
In neurons, as in other excitable cells, mitochondria extrude Ca(2+) ions from their matrix in exchange with cytosolic Na(+) ions. This exchange is mediated by a specific transporter located in the inner mitochondrial membrane, the mitochondrial Na(+)/Ca(2+) exchanger (NCX(mito)). The stoichiometry of NCX(mito)-operated Na(+)/Ca(2+) exchange has been the subject of a long controversy, but evidence of an electrogenic 3 Na(+)/1 Ca(2+) exchange is increasing. Although the molecular identity of NCX(mito) is still undetermined, data obtained in our laboratory suggest that besides the long-sought and as yet unfound mitochondrial-specific NCX, the three isoforms of plasmamembrane NCX can contribute to NCX(mito) in neurons and astrocytes. NCX(mito) has a role in controlling neuronal Ca(2+) homeostasis and neuronal bioenergetics. Indeed, by cycling the Ca(2+) ions captured by mitochondria back to the cytosol, NCX(mito) determines a shoulder in neuronal [Ca(2+)](c) responses to neurotransmitters and depolarizing stimuli which may then outlast stimulus duration. This persistent NCX(mito)-dependent Ca(2+) release has a role in post-tetanic potentiation, a form of short-term synaptic plasticity. By controlling [Ca(2+)](m) NCX(mito) regulates the activity of the Ca(2+)-sensitive enzymes pyruvate-, alpha-ketoglutarate- and isocitrate-dehydrogenases and affects the activity of the respiratory chain. Convincing experimental evidence suggests that supraphysiological activation of NCX(mito) contributes to neuronal cell death in the ischemic brain and, in epileptic neurons coping with seizure-induced ion overload, reduces the ability to reestablish normal ionic homeostasis. These data suggest that NCX(mito) could represent an important target for the development of new neurological drugs.
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Affiliation(s)
- P Castaldo
- Department of Neuroscience, Section of Pharmacology, Università Politecnica delle Marche, Via Tronto 10/A, 60020 Torrette di Ancona, Ancona, Italy
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24
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Lu VB, Ballanyi K, Colmers WF, Smith PA. Neuron type-specific effects of brain-derived neurotrophic factor in rat superficial dorsal horn and their relevance to 'central sensitization'. J Physiol 2007; 584:543-63. [PMID: 17761774 PMCID: PMC2277149 DOI: 10.1113/jphysiol.2007.141267] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Chronic constriction injury (CCI) of the rat sciatic nerve increases the excitability of the spinal dorsal horn. This 'central sensitization' leads to pain behaviours analogous to human neuropathic pain. We have established that CCI increases excitatory synaptic drive to putative excitatory, 'delay' firing neurons in the substantia gelatinosa but attenuates that to putative inhibitory, 'tonic' firing neurons. Here, we use a defined-medium organotypic culture (DMOTC) system to investigate the long-term actions of brain-derived neurotrophic factor (BDNF) as a possible instigator of these changes. The age of the cultures and their 5-6 day exposure to BDNF paralleled the protocol used for CCI in vivo. Effects of BDNF (200 ng ml(-1)) in DMOTC were reminiscent of those seen with CCI in vivo. These included decreased synaptic drive to 'tonic' neurons and increased synaptic drive to 'delay' neurons with only small effects on their membrane excitability. Actions of BDNF on 'delay' neurons were exclusively presynaptic and involved increased mEPSC frequency and amplitude without changes in the function of postsynaptic AMPA receptors. By contrast, BDNF exerted both pre- and postsynaptic actions on 'tonic' cells; mEPSC frequency and amplitude were decreased and the decay time constant reduced by 35%. These selective and differential actions of BDNF on excitatory and inhibitory neurons contributed to a global increase in dorsal horn network excitability as assessed by the amplitude of depolarization-induced increases in intracellular Ca(2+). Such changes and their underlying cellular mechanisms are likely to contribute to CCI-induced 'central sensitization' and hence to the onset of neuropathic pain.
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Affiliation(s)
- Van B Lu
- Department of Pharmacology, University of Alberta, 9.75 Medical Sciences Building, Edmonton, Alberta, Canada
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25
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Furlan F, Taccola G, Grandolfo M, Guasti L, Arcangeli A, Nistri A, Ballerini L. ERG conductance expression modulates the excitability of ventral horn GABAergic interneurons that control rhythmic oscillations in the developing mouse spinal cord. J Neurosci 2007; 27:919-28. [PMID: 17251434 PMCID: PMC6672895 DOI: 10.1523/jneurosci.4035-06.2007] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
During antenatal development, the operation and maturation of mammalian spinal networks strongly depend on the activity of ventral horn GABAergic interneurons that mediate excitation first and inhibition later. Although the functional consequence of GABA actions may depend on maturational processes in target neurons, it is also likely that evolving changes in GABAergic transmission require fine-tuning in GABA release, probably via certain intrinsic mechanisms regulating GABAergic neuron excitability at different embryonic stages. Nevertheless, it has not been possible, to date, to identify certain ionic conductances upregulated or downregulated before birth in such cells. By using an experimental model with either mouse organotypic spinal cultures or isolated spinal cord preparations, the present study examined the role of the ERG current (I(K(ERG))), a potassium conductance expressed by developing, GABA-immunoreactive spinal neurons. In organotypic cultures, only ventral interneurons with fast adaptation and GABA immunoreactivity, and only after 1 week in culture, were transformed into high-frequency bursters by E4031, a selective inhibitor of I(K(ERG)) that also prolonged and made more regular spontaneous bursts. In the isolated spinal cord in which GABA immunoreactivity and m-erg mRNA were colocalized in interneurons, ventral root rhythms evoked by NMDA plus 5-hydroxytryptamine were stabilized and synchronized by E4031. All of these effects were lost after 2 weeks in culture or before birth in coincidence with decreased m-erg expression. These data suggest that, during an early stage of spinal cord development, the excitability of GABAergic ventral interneurons important for circuit maturation depended, at least in part, on the function of I(K(ERG)).
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Affiliation(s)
- Francesco Furlan
- Physiology and Pathology Department, Center for Neuroscience B.R.A.I.N., University of Trieste, 34127 Trieste, Italy
| | - Giuliano Taccola
- Neurobiology Sector, International School for Advanced Studies, 34014 Trieste, Italy, and SPINAL Project, Udine
| | - Micaela Grandolfo
- Neurobiology Sector, International School for Advanced Studies, 34014 Trieste, Italy, and SPINAL Project, Udine
| | - Leonardo Guasti
- Department of Experimental Pathology and Oncology, University of Firenze, 50134 Firenze, Italy
| | - Annarosa Arcangeli
- Department of Experimental Pathology and Oncology, University of Firenze, 50134 Firenze, Italy
| | - Andrea Nistri
- Neurobiology Sector, International School for Advanced Studies, 34014 Trieste, Italy, and SPINAL Project, Udine
| | - Laura Ballerini
- Physiology and Pathology Department, Center for Neuroscience B.R.A.I.N., University of Trieste, 34127 Trieste, Italy
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