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Ficiarà E, Molinar C, Gazzin S, Jayanti S, Argenziano M, Nasi L, Casoli F, Albertini F, Ansari SA, Marcantoni A, Tomagra G, Carabelli V, Guiot C, D’Agata F, Cavalli R. Developing Iron Nanochelating Agents: Preliminary Investigation of Effectiveness and Safety for Central Nervous System Applications. Int J Mol Sci 2024; 25:729. [PMID: 38255803 PMCID: PMC10815234 DOI: 10.3390/ijms25020729] [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: 11/24/2023] [Revised: 12/31/2023] [Accepted: 01/02/2024] [Indexed: 01/24/2024] Open
Abstract
Excessive iron levels are believed to contribute to the development of neurodegenerative disorders by promoting oxidative stress and harmful protein clustering. Novel chelation treatments that can effectively remove excess iron while minimizing negative effects on the nervous system are being explored. This study focuses on the creation and evaluation of innovative nanobubble (NB) formulations, shelled with various polymers such as glycol-chitosan (GC) and glycol-chitosan conjugated with deferoxamine (DFO), to enhance their ability to bind iron. Various methods were used to evaluate their physical and chemical properties, chelation capacity in diverse iron solutions and impact on reactive oxygen species (ROS). Notably, the GC-DFO NBs demonstrated the ability to decrease amyloid-β protein misfolding caused by iron. To assess potential toxicity, in vitro cytotoxicity testing was conducted using organotypic brain cultures from the substantia nigra, revealing no adverse effects at appropriate concentrations. Additionally, the impact of NBs on spontaneous electrical signaling in hippocampal neurons was examined. Our findings suggest a novel nanochelation approach utilizing DFO-conjugated NBs for the removal of excess iron in cerebral regions, potentially preventing neurotoxic effects.
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Affiliation(s)
- Eleonora Ficiarà
- School of Pharmacy, Center for Neuroscience, University of Camerino, 62032 Camerino, Italy;
| | - Chiara Molinar
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (C.M.); (M.A.); (A.M.); (G.T.); (V.C.); (R.C.)
| | - Silvia Gazzin
- Fondazione Italiana Fegato-Onlus, Bldg. Q, AREA Science Park, ss14, Km 163.5, Basovizza, 34149 Trieste, Italy; (S.G.); (S.J.)
| | - Sri Jayanti
- Fondazione Italiana Fegato-Onlus, Bldg. Q, AREA Science Park, ss14, Km 163.5, Basovizza, 34149 Trieste, Italy; (S.G.); (S.J.)
| | - Monica Argenziano
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (C.M.); (M.A.); (A.M.); (G.T.); (V.C.); (R.C.)
| | - Lucia Nasi
- Institute of Materials for Electronics and Magnetism (IMEM) CNR, Parco Area delle Scienze 37/A, 43124 Parma, Italy; (L.N.); (F.C.); (F.A.)
| | - Francesca Casoli
- Institute of Materials for Electronics and Magnetism (IMEM) CNR, Parco Area delle Scienze 37/A, 43124 Parma, Italy; (L.N.); (F.C.); (F.A.)
| | - Franca Albertini
- Institute of Materials for Electronics and Magnetism (IMEM) CNR, Parco Area delle Scienze 37/A, 43124 Parma, Italy; (L.N.); (F.C.); (F.A.)
| | - Shoeb Anwar Ansari
- Department of Neurosciences, University of Turin, 10124 Turin, Italy; (S.A.A.); (C.G.)
| | - Andrea Marcantoni
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (C.M.); (M.A.); (A.M.); (G.T.); (V.C.); (R.C.)
| | - Giulia Tomagra
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (C.M.); (M.A.); (A.M.); (G.T.); (V.C.); (R.C.)
| | - Valentina Carabelli
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (C.M.); (M.A.); (A.M.); (G.T.); (V.C.); (R.C.)
| | - Caterina Guiot
- Department of Neurosciences, University of Turin, 10124 Turin, Italy; (S.A.A.); (C.G.)
| | - Federico D’Agata
- Department of Neurosciences, University of Turin, 10124 Turin, Italy; (S.A.A.); (C.G.)
| | - Roberta Cavalli
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (C.M.); (M.A.); (A.M.); (G.T.); (V.C.); (R.C.)
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Tomagra G, Franchino C, Cesano F, Chiarion G, de lure A, Carbone E, Calabresi P, Mesin L, Picconi B, Marcantoni A, Carabelli V. Alpha-synuclein oligomers alter the spontaneous firing discharge of cultured midbrain neurons. Front Cell Neurosci 2023; 17:1078550. [PMID: 36744002 PMCID: PMC9896582 DOI: 10.3389/fncel.2023.1078550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 01/06/2023] [Indexed: 01/21/2023] Open
Abstract
The aim of this work was to monitor the effects of extracellular α-synuclein on the firing activity of midbrain neurons dissociated from substantia nigra TH-GFP mice embryos and cultured on microelectrode arrays (MEA). We monitored the spontaneous firing discharge of the network for 21 days after plating and the role of glutamatergic and GABAergic inputs in regulating burst generation and network synchronism. Addition of GABA A , AMPA and NMDA antagonists did not suppress the spontaneous activity but allowed to identify three types of neurons that exhibited different modalities of firing and response to applied L-DOPA: high-rate (HR) neurons, low-rate pacemaking (LR-p), and low-rate non-pacemaking (LR-np) neurons. Most HR neurons were insensitive to L-DOPA, while the majority of LR-p neurons responded with a decrease of the firing discharge; less defined was the response of LR-np neurons. The effect of exogenous α-synuclein (α-syn) on the firing discharge of midbrain neurons was then studied by varying the exposure time (0-48 h) and the α-syn concentration (0.3-70 μM), while the formation of α-syn oligomers was monitored by means of AFM. Independently of the applied concentration, acute exposure to α-syn monomers did not exert any effect on the spontaneous firing rate of HR, LR-p, and LR-np neurons. On the contrary, after 48 h exposure, the firing activity was drastically altered at late developmental stages (14 days in vitro, DIV, neurons): α-syn oligomers progressively reduced the spontaneous firing discharge (IC50 = 1.03 μM), impaired burst generation and network synchronism, proportionally to the increased oligomer/monomer ratio. Different effects were found on early-stage developed neurons (9 DIV), whose firing discharge remained unaltered, regardless of the applied α-syn concentration and the exposure time. Our findings unravel, for the first time, the variable effects of exogenous α-syn at different stages of midbrain network development and provide new evidence for the early detection of neuronal function impairment associated to aggregated forms of α-syn.
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Affiliation(s)
- Giulia Tomagra
- Drug Science Department, University of Torino, Turin, Italy
- Nanostructured Interfaces and Surfaces Inter-Departmental Research Centre, Turin, Italy
| | | | - Federico Cesano
- Nanostructured Interfaces and Surfaces Inter-Departmental Research Centre, Turin, Italy
- Department of Chemistry and INSTM-UdR Torino, Turin, Italy
| | - Giovanni Chiarion
- Mathematical Biology and Physiology, Department of Electronics and Telecommunications, Turin, Italy
| | - Antonio de lure
- Laboratory Experimental Neurophysiology, IRCCS San Raffaele Rome, Rome, Italy
| | - Emilio Carbone
- Drug Science Department, University of Torino, Turin, Italy
- Nanostructured Interfaces and Surfaces Inter-Departmental Research Centre, Turin, Italy
| | - Paolo Calabresi
- Neurological Clinic, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
- Neurology, Department of Neuroscience, Faculty of Medicine, Università Cattolica del “Sacro Cuore,”Rome, Italy
| | - Luca Mesin
- Mathematical Biology and Physiology, Department of Electronics and Telecommunications, Turin, Italy
| | - Barbara Picconi
- Laboratory Experimental Neurophysiology, IRCCS San Raffaele Rome, Rome, Italy
- Dipartimento di Scienze Umane e Promozione della Qualitá della Vita, Telematic University San Raffaele Roma, Rome, Italy
| | - Andrea Marcantoni
- Drug Science Department, University of Torino, Turin, Italy
- Nanostructured Interfaces and Surfaces Inter-Departmental Research Centre, Turin, Italy
| | - Valentina Carabelli
- Drug Science Department, University of Torino, Turin, Italy
- Nanostructured Interfaces and Surfaces Inter-Departmental Research Centre, Turin, Italy
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Marcantoni A, Chiantia G, Tomagra G, Hidisoglu E, Franchino C, Carabelli V, Carbone E. Two firing modes and well-resolved Na +, K +, and Ca 2+ currents at the cell-microelectrode junction of spontaneously active rat chromaffin cell on MEAs. Pflugers Arch 2023; 475:181-202. [PMID: 36260174 PMCID: PMC9849155 DOI: 10.1007/s00424-022-02761-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/23/2022] [Accepted: 10/07/2022] [Indexed: 02/01/2023]
Abstract
We recorded spontaneous extracellular action potentials (eAPs) from rat chromaffin cells (CCs) at 37 °C using microelectrode arrays (MEAs) and compared them with intracellularly recorded APs (iAPs) through conventional patch clamp recordings at 22 °C. We show the existence of two distinct firing modes on MEAs: a ~ 4 Hz irregular continuous firing and a frequent intermittent firing mode where periods of high-intraburst frequency (~ 8 Hz) of ~ 7 s duration are interrupted by silent periods of ~ 12 s. eAPs occurred either as negative- or positive-going signals depending on the contact between cell and microelectrode: either predominantly controlled by junction-membrane ion channels (negative-going) or capacitive/ohmic coupling (positive-going). Negative-going eAPs were found to represent the trajectory of the Na+, Ca2+, and K+ currents passing through the cell area in tight contact with the microelectrode during an AP (point-contact junction). The inward Nav component of eAPs was blocked by TTX in a dose-dependent manner (IC50 ~ 10 nM) while the outward component was strongly attenuated by the BK channel blocker paxilline (200 nM) or TEA (5 mM). The SK channel blocker apamin (200 nM) had no effect on eAPs. Inward Nav and Cav currents were well-resolved after block of Kv and BK channels or in cells showing no evident outward K+ currents. Unexpectedly, on the same type of cells, we could also resolve inward L-type currents after adding nifedipine (3 μM). In conclusion, MEAs provide a direct way to record different firing modes of rat CCs and to estimate the Na+, Ca2+, and K+ currents that sustain cell firing and spontaneous catecholamines secretion.
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Affiliation(s)
- Andrea Marcantoni
- grid.7605.40000 0001 2336 6580Department of Drug Science, Laboratory of Cell Physiology and Molecular Neuroscience, N.I.S. Centre, University of Torino, Corso Raffaello 30, 10125 Turin, Italy
| | - Giuseppe Chiantia
- grid.7605.40000 0001 2336 6580Department of Neuroscience, University of Torino, 10125 Turin, Italy
| | - Giulia Tomagra
- grid.7605.40000 0001 2336 6580Department of Drug Science, Laboratory of Cell Physiology and Molecular Neuroscience, N.I.S. Centre, University of Torino, Corso Raffaello 30, 10125 Turin, Italy
| | - Enis Hidisoglu
- grid.7605.40000 0001 2336 6580Department of Drug Science, Laboratory of Cell Physiology and Molecular Neuroscience, N.I.S. Centre, University of Torino, Corso Raffaello 30, 10125 Turin, Italy
| | - Claudio Franchino
- grid.7605.40000 0001 2336 6580Department of Drug Science, Laboratory of Cell Physiology and Molecular Neuroscience, N.I.S. Centre, University of Torino, Corso Raffaello 30, 10125 Turin, Italy
| | - Valentina Carabelli
- grid.7605.40000 0001 2336 6580Department of Drug Science, Laboratory of Cell Physiology and Molecular Neuroscience, N.I.S. Centre, University of Torino, Corso Raffaello 30, 10125 Turin, Italy
| | - Emilio Carbone
- grid.7605.40000 0001 2336 6580Department of Drug Science, Laboratory of Cell Physiology and Molecular Neuroscience, N.I.S. Centre, University of Torino, Corso Raffaello 30, 10125 Turin, Italy
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Hidisoglu E, Chiantia G, Franchino C, Tomagra G, Giustetto M, Carbone E, Carabelli V, Marcantoni A. The ryanodine receptor-calstabin interaction stabilizer S107 protects hippocampal neurons from GABAergic synaptic alterations induced by Abeta42 oligomers. J Physiol 2022; 600:5295-5309. [PMID: 36284365 DOI: 10.1113/jp283537] [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: 07/04/2022] [Accepted: 10/12/2022] [Indexed: 01/05/2023] Open
Abstract
The oligomeric form of the peptide amyloid beta 42 (Abeta42) contributes to the development of synaptic abnormalities and cognitive impairments associated with Alzheimer's disease (AD). To date, there is a gap in knowledge regarding how Abeta42 alters the elementary parameters of GABAergic synaptic function. Here we found that Abeta42 increased the frequency and amplitude of miniature GABAergic currents as well as the amplitude of evoked inhibitory postsynaptic currents. When we focused on paired pulse depression (PPD) to establish whether GABA release probability was affected by Abeta42, we did not observe any significant change. On the other hand, a more detailed investigation of the presynaptic effects induced by Abeta42 by means of multiple probability fluctuation analysis and cumulative amplitude analysis showed an increase in both the size of the readily releasable pool responsible for synchronous release and the number of release sites. We further explored whether ryanodine receptors (RyRs) contributed to exacerbating these changes by stabilizing the interaction between RyRs and the accessory protein calstabin. We observed that the RyR-calstabin interaction stabilizer S107 restored the synaptic parameters to values comparable to those measured in control conditions. In conclusion, our results clarify the mechanisms of potentiation of GABAergic synapses induced by Abeta42. We further suggest that RyRs are involved in the control of synaptic activity during the early stage of AD onset and that their stabilization could represent a new therapeutical approach for AD treatment. KEY POINTS: Accumulation of the peptide amyloid beta 42 (Abeta42) is a key characteristic of Alzheimer's disease (AD) and causes synaptic dysfunctions. To date, the effects of Abeta42 accumulation on GABAergic synapses are poorly understood. The findings reported here suggest that, similarly to what is observed on glutamatergic synapses, Abeta42 modifies GABAergic synapses by targeting ryanodine receptors and causing calcium dysregulation. The GABAergic impairments can be restored by the ryanodine receptor-calstabin interaction stabilizer S107. Based on this research, RyRs stabilization may represent a novel pharmaceutical strategy for preventing or delaying AD.
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Affiliation(s)
- Enis Hidisoglu
- Department of Drug Science and Technology, NIS Centre, University of Turin, Turin, Italy
| | | | - Claudio Franchino
- Department of Drug Science and Technology, NIS Centre, University of Turin, Turin, Italy
| | - Giulia Tomagra
- Department of Drug Science and Technology, NIS Centre, University of Turin, Turin, Italy
| | | | - Emilio Carbone
- Department of Drug Science and Technology, NIS Centre, University of Turin, Turin, Italy
| | - Valentina Carabelli
- Department of Drug Science and Technology, NIS Centre, University of Turin, Turin, Italy
| | - Andrea Marcantoni
- Department of Drug Science and Technology, NIS Centre, University of Turin, Turin, Italy
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5
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Xu L, Li Q, Ke Y, Yung WH. Chronic Intermittent Hypoxia-Induced Aberrant Neural Activities in the Hippocampus of Male Rats Revealed by Long-Term in vivo Recording. Front Cell Neurosci 2022; 15:784045. [PMID: 35126057 PMCID: PMC8813782 DOI: 10.3389/fncel.2021.784045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/13/2021] [Indexed: 11/13/2022] Open
Abstract
Chronic intermittent hypoxia (CIH) occurs in obstructive sleep apnea (OSA), a common sleep-disordered breathing associated with malfunctions in multiple organs including the brain. How OSA-associated CIH impacts on brain activities and functions leading to neurocognitive impairment is virtually unknown. Here, by means of in vivo electrophysiological recordings via chronically implanted multi-electrode arrays in male rat model of OSA, we found that both putative pyramidal neurons and putative interneurons in the hippocampal CA1 subfield were hyper-excitable during the first week of CIH treatment and followed by progressive suppression of neural firing in the longer term. Partial recovery of the neuronal activities was found after normoxia treatment but only in putative pyramidal neurons. These findings correlated well to abnormalities in dendritic spine morphogenesis of these neurons. The results reveal that hippocampal neurons respond to CIH in a complex biphasic and bidirectional manner eventually leading to suppression of firing activities. Importantly, these changes are attributed to a larger extent to impaired functions of putative interneurons than putative pyramidal neurons. Our findings therefore revealed functional and structural damages in central neurons in OSA subjects.
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Affiliation(s)
- Linhao Xu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Department of Cardiology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qian Li
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Ya Ke
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Gerald Choa Neuroscience Centre, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
- *Correspondence: Wing-Ho Yung
| | - Wing-Ho Yung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Gerald Choa Neuroscience Centre, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Ya Ke
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Fiskum V, Sandvig A, Sandvig I. Silencing of Activity During Hypoxia Improves Functional Outcomes in Motor Neuron Networks in vitro. Front Integr Neurosci 2021; 15:792863. [PMID: 34975426 PMCID: PMC8716921 DOI: 10.3389/fnint.2021.792863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 12/01/2021] [Indexed: 11/13/2022] Open
Abstract
The effects of hypoxia, or reduced oxygen supply, to brain tissue can be disastrous, leading to extensive loss of function. Deoxygenated tissue becomes unable to maintain healthy metabolism, which leads to increased production of reactive oxygen species (ROS) and loss of calcium homoeostasis, with damaging downstream effects. Neurons are a highly energy demanding cell type, and as such they are highly sensitive to reductions in oxygenation and some types of neurons such as motor neurons are even more susceptible to hypoxic damage. In addition to the immediate deleterious effects hypoxia can have on neurons, there can be delayed effects which lead to increased risk of developing neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), even if no immediate consequences are apparent. Furthermore, impairment of the function of various hypoxia-responsive factors has been shown to increase the risk of developing several neurodegenerative disorders. Longitudinal assessment of electrophysiological network activity is underutilised in assessing the effects of hypoxia on neurons and how their activity and communication change over time following a hypoxic challenge. This study utilised multielectrode arrays and motor neuron networks to study the response to hypoxia and the subsequent development of the neuronal activity over time, as well as the effect of silencing network activity during the hypoxic challenge. We found that motor neuron networks exposed to hypoxic challenge exhibited a delayed fluctuation in multiple network activity parameters compared to normoxic networks. Silencing of activity during the hypoxic challenge leads to maintained bursting activity, suggesting that functional outcomes are better maintained in these networks and that there are activity-dependent mechanisms involved in the network damage following hypoxia.
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Affiliation(s)
- Vegard Fiskum
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Axel Sandvig
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
- Department of Neurology, St. Olav’s Hospital, Trondheim University Hospital, Trondheim, Norway
- Department of Pharmacology and Clinical Neurosciences, Division of Neuro, Head, and Neck, Umeå University Hospital, Umeå, Sweden
- Department of Community Medicine and Rehabilitation, Umeå University, Umeå, Sweden
| | - Ioanna Sandvig
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
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Tanskanen JM, Ahtiainen A, Hyttinen JA. Toward Closed-Loop Electrical Stimulation of Neuronal Systems: A Review. Bioelectricity 2020; 2:328-347. [PMID: 34471853 PMCID: PMC8370352 DOI: 10.1089/bioe.2020.0028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Biological neuronal cells communicate using neurochemistry and electrical signals. The same phenomena also allow us to probe and manipulate neuronal systems and communicate with them. Neuronal system malfunctions cause a multitude of symptoms and functional deficiencies that can be assessed and sometimes alleviated by electrical stimulation. Our working hypothesis is that real-time closed-loop full-duplex measurement and stimulation paradigms can provide more in-depth insight into neuronal networks and enhance our capability to control diseases of the nervous system. In this study, we review extracellular electrical stimulation methods used in in vivo, in vitro, and in silico neuroscience research and in the clinic (excluding methods mainly aimed at neuronal growth and other similar effects) and highlight the potential of closed-loop measurement and stimulation systems. A multitude of electrical stimulation and measurement-based methods are widely used in research and the clinic. Closed-loop methods have been proposed, and some are used in the clinic. However, closed-loop systems utilizing more complex measurement analysis and adaptive stimulation systems, such as artificial intelligence systems connected to biological neuronal systems, do not yet exist. Our review promotes the research and development of intelligent paradigms aimed at meaningful communications between neuronal and information and communications technology systems, "dialogical paradigms," which have the potential to take neuroscience and clinical methods to a new level.
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Affiliation(s)
- Jarno M.A. Tanskanen
- BioMediTech Institute and Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Annika Ahtiainen
- BioMediTech Institute and Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Jari A.K. Hyttinen
- BioMediTech Institute and Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
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Konduri AK, Deepak CS, Purohit S, Narayan KS. An integrated 3D fluidic device with bubble guidance mechanism for long-term primary and secondary cell recordings on multi-electrode array platform. Biofabrication 2020; 12:045019. [PMID: 32650326 DOI: 10.1088/1758-5090/aba500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A 3D fluidic device (3D-FD) is designed and developed with the capability of auto bubble guidance via a helical pathway in a 3D geometry. This assembly is integrated to a multi-electrode array (MEA) to maintain secondary cell lines, primary cells and primary retinal tissue explants of chick embryos for continuous monitoring of the growth and electrophysiology recording. The ability to maintain the retinal tissue explant, extracted from day 14 (E-14) and day 21 (E-21) chick embryos in an integrated 3D-FD MEA for long duration (>100 h) and study the development is demonstrated. The enhanced duration of monitoring offered by this device is due to the controlled laminar flow and the maintenance of a stable microenvironment. The spontaneous electrical activity of the retina, including the spike recordings from the retinal ganglion layer, was monitored over a long duration. Specifically, the spiking activity in embryonic chick retinas of different days (E-14 to 21) is studied, and the presence of light-stimulated firings along with a distinct electroretinogram for E-21 mature retina provides the evidence of a stable microenvironment over a sustained period.
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Affiliation(s)
- Anil Krishna Konduri
- Chemistry and Physics of Material Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur-560064, Bangalore, Karnataka, India
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9
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Marcantoni A, Calorio C, Hidisoglu E, Chiantia G, Carbone E. Cav1.2 channelopathies causing autism: new hallmarks on Timothy syndrome. Pflugers Arch 2020; 472:775-789. [PMID: 32621084 DOI: 10.1007/s00424-020-02430-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 02/07/2023]
Abstract
Cav1.2 L-type calcium channels play key roles in long-term synaptic plasticity, sensory transduction, muscle contraction, and hormone release. De novo mutations in the gene encoding Cav1.2 (CACNA1C) causes two forms of Timothy syndrome (TS1, TS2), characterized by a multisystem disorder inclusive of cardiac arrhythmias, long QT, autism, and adrenal gland dysfunction. In both TS1 and TS2, the missense mutation G406R is on the alternatively spliced exon 8 and 8A coding for the IS6-helix of Cav1.2 and is responsible for the penetrant form of autism in most TS individuals. The mutation causes specific gain-of-function changes to Cav1.2 channel gating: a "leftward shift" of voltage-dependent activation, reduced voltage-dependent inactivation, and a "leftward shift" of steady-state inactivation. How this occurs and how Cav1.2 gating changes alter neuronal firing and synaptic plasticity is still largely unexplained. Trying to better understanding the molecular basis of Cav1.2 gating dysfunctions leading to autism, here, we will present and discuss the properties of recently reported typical and atypical TS phenotypes and the effective gating changes exhibited by missense mutations associated with long QTs without extracardiac symptoms, unrelated to TS. We will also discuss new emerging views achieved from using iPSCs-derived neurons and the newly available autistic TS2-neo mouse model, both appearing promising for understanding neuronal mistuning in autistic TS patients. We will also analyze and describe recent proposals of molecular pathways that might explain mistuned Ca2+-mediated and Ca2+-independent excitation-transcription signals to the nucleus. Briefly, we will also discuss possible pharmacological approaches to treat autism associated with L-type channelopathies.
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Affiliation(s)
- Andrea Marcantoni
- Department of Drug Science, Laboratory of Cellular and Molecular Neuroscience, N.I.S. Centre, Corso Raffaello 30, 10125, Torino, Italy
| | - Chiara Calorio
- Department of Drug Science, Laboratory of Cellular and Molecular Neuroscience, N.I.S. Centre, Corso Raffaello 30, 10125, Torino, Italy
| | - Enis Hidisoglu
- Department of Biophysics, Faculty of Medicine, Akdeniz University, Antalya, Turkey
| | - Giuseppe Chiantia
- Department of Drug Science, Laboratory of Cellular and Molecular Neuroscience, N.I.S. Centre, Corso Raffaello 30, 10125, Torino, Italy
| | - Emilio Carbone
- Department of Drug Science, Laboratory of Cellular and Molecular Neuroscience, N.I.S. Centre, Corso Raffaello 30, 10125, Torino, Italy.
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10
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Del Pino I, Tocco C, Magrinelli E, Marcantoni A, Ferraguto C, Tomagra G, Bertacchi M, Alfano C, Leinekugel X, Frick A, Studer M. COUP-TFI/Nr2f1 Orchestrates Intrinsic Neuronal Activity during Development of the Somatosensory Cortex. Cereb Cortex 2020; 30:5667-5685. [DOI: 10.1093/cercor/bhaa137] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/17/2020] [Accepted: 04/29/2020] [Indexed: 01/19/2023] Open
Abstract
Abstract
The formation of functional cortical maps in the cerebral cortex results from a timely regulated interaction between intrinsic genetic mechanisms and electrical activity. To understand how transcriptional regulation influences network activity and neuronal excitability within the neocortex, we used mice deficient for Nr2f1 (also known as COUP-TFI), a key determinant of primary somatosensory (S1) area specification during development. We found that the cortical loss of Nr2f1 impacts on spontaneous network activity and synchronization of S1 cortex at perinatal stages. In addition, we observed alterations in the intrinsic excitability and morphological features of layer V pyramidal neurons. Accordingly, we identified distinct voltage-gated ion channels regulated by Nr2f1 that might directly influence intrinsic bioelectrical properties during critical time windows of S1 cortex specification. Altogether, our data suggest a tight link between Nr2f1 and neuronal excitability in the developmental sequence that ultimately sculpts the emergence of cortical network activity within the immature neocortex.
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Affiliation(s)
- Isabel Del Pino
- Université de Bordeaux, Inserm U1215, Neurocentre Magendie, 33077 Bordeaux, France
- Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Chiara Tocco
- Université Côte d’Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Elia Magrinelli
- Université Côte d’Azur, CNRS, Inserm, iBV, 06108 Nice, France
- Département des Neurosciences Fondamentales, Université de Lausanne, CH-1005 Lausanne, Switzerland
| | - Andrea Marcantoni
- Dipartimento di Scienza e Tecnologia del Farmaco, Università di Torino, 10125 Torino, Italy
| | | | - Giulia Tomagra
- Dipartimento di Scienza e Tecnologia del Farmaco, Università di Torino, 10125 Torino, Italy
| | | | | | - Xavier Leinekugel
- Université de Bordeaux, Inserm U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Andreas Frick
- Université de Bordeaux, Inserm U1215, Neurocentre Magendie, 33077 Bordeaux, France
| | - Michèle Studer
- Université Côte d’Azur, CNRS, Inserm, iBV, 06108 Nice, France
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11
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Marcantoni A, Cerullo MS, Buxeda P, Tomagra G, Giustetto M, Chiantia G, Carabelli V, Carbone E. Amyloid Beta42 oligomers up-regulate the excitatory synapses by potentiating presynaptic release while impairing postsynaptic NMDA receptors. J Physiol 2020; 598:2183-2197. [PMID: 32246769 DOI: 10.1113/jp279345] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/26/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS NMDA receptors (NMDARs) are key molecules for controlling neuronal plasticity, learning and memory processes. Their function is impaired during Alzheimer's disease (AD) but the exact consequence on synaptic function is not yet fully identified. An important hallmark of AD onset is represented by the neuronal accumulation of Amyloid Beta42 oligomers (Abeta42) that we have recently shown to be responsible for the increased intracellular Ca2+ concentration through ryanodine receptors (RyRs). Here we characterized the effects of Abeta42 on NMDA synapses showing specific pre- and post-synaptic functional changes that lead to a potentiation of basal and synchronous NMDA synaptic transmission. These overall effects can be abolished by decreasing Ca2+ release from RyRs with specific inhibitors that we propose as new pharmacological tools for AD treatment. ABSTRACT We have recently shown that Amyloid Beta42 oligomers (Abeta42) cause calcium dysregulation in hippocampal neurons by stimulating Ca2+ release from ryanodine receptors (RyRs) and inhibiting Ca2+ entry through NMDA receptors (NMDARs). Here, we found that Abeta42 decrease the average NMDA-activated inward current and that Ca2+ entry through NMDARs is accompanied by Ca2+ release from the stores. The overall amount of intraellular Ca2+ concentration([Ca2+ ]i ) increase during NMDA application is 50% associated with RyR opening and 50% with NMDARs activation. Addition of Abeta42 does not change this proportion. We estimated the number of NMDARs expressed in hippocampal neurons and their unitary current. We found that Abeta42 decrease the number of NMDARs without altering their unitary current. Paradoxically, the oligomer increases the size of electrically evoked eEPSCs induced by NMDARs activation. We found that this is the consequence of the increased release probability (p) of glutamate and the number of release sites (N) of NMDA synapses, while the quantal size (q) is significantly decreased as expected from the decreased number of NMDARs. An increased number of release sites induced by Abeta42 is also supported by the increased size of the ready releasable pool (RRPsyn) and by the enhanced percentage of paired pulse depression (PPD). Interestingly, the RyRs inhibitor dantrolene prevents the increase of PPD induced by Abeta42 oligomers. In conclusion, Abeta42 up-regulates NMDA synaptic responses with a mechanism involving RyRs that occurs during the early stages of Alzheimer's disease (AD) onset. This suggests that new selective modulators of RyRs may be useful for designing effective therapies to treat AD patients.
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Affiliation(s)
| | | | - Pol Buxeda
- Department of Drug Science and Technology, Torino University, Italy
| | - Giulia Tomagra
- Department of Drug Science and Technology, Torino University, Italy
| | - Maurizio Giustetto
- Department of Neurosciences / National Institute of Neuroscience, Torino University, Italy.,National Institute of Neuroscience-Italy, Turin, Italy
| | | | | | - Emilio Carbone
- Department of Drug Science and Technology, Torino University, Italy
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12
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Russo I, Gavello D, Menna E, Vandael D, Veglia C, Morello N, Corradini I, Focchi E, Alfieri A, Angelini C, Bianchi FT, Morellato A, Marcantoni A, Sassoè-Pognetto M, Ottaviani MM, Yekhlef L, Giustetto M, Taverna S, Carabelli V, Matteoli M, Carbone E, Turco E, Defilippi P. p140Cap Regulates GABAergic Synaptogenesis and Development of Hippocampal Inhibitory Circuits. Cereb Cortex 2020; 29:91-105. [PMID: 29161354 DOI: 10.1093/cercor/bhx306] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/23/2017] [Indexed: 01/19/2023] Open
Abstract
The neuronal scaffold protein p140Cap was investigated during hippocampal network formation. p140Cap is present in presynaptic GABAergic terminals and its genetic depletion results in a marked alteration of inhibitory synaptic activity. p140Cap-/- cultured neurons display higher frequency of miniature inhibitory postsynaptic currents (mIPSCs) with no changes of their mean amplitude. Consistent with a potential presynaptic alteration of basal GABA release, p140Cap-/- neurons exhibit a larger synaptic vesicle readily releasable pool, without any variation of single GABAA receptor unitary currents and number of postsynaptic channels. Furthermore, p140Cap-/- neurons show a premature and enhanced network synchronization and appear more susceptible to 4-aminopyridine-induced seizures in vitro and to kainate-induced seizures in vivo. The hippocampus of p140Cap-/- mice showed a significant increase in the number of both inhibitory synapses and of parvalbumin- and somatostatin-expressing interneurons. Specific deletion of p140Cap in forebrain interneurons resulted in increased susceptibility to in vitro epileptic events and increased inhibitory synaptogenesis, comparable to those observed in p140Cap-/- mice. Altogether, our data demonstrate that p140Cap finely tunes inhibitory synaptogenesis and GABAergic neurotransmission, thus regulating the establishment and maintenance of the proper hippocampal excitatory/inhibitory balance.
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Affiliation(s)
- Isabella Russo
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Daniela Gavello
- Department of Drug Science, University of Torino, Torino, Italy.,NIS Centre of Excellence, Torino, Italy
| | - Elisabetta Menna
- Institute of Neuroscience, CNR, Milano, Italy.,Istituto Clinico Humanitas, IRCCS, Rozzano, Italy
| | - David Vandael
- Department of Drug Science, University of Torino, Torino, Italy.,NIS Centre of Excellence, Torino, Italy
| | - Carola Veglia
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Noemi Morello
- Department of Neuroscience, University of Torino, Torino, Italy
| | - Irene Corradini
- Institute of Neuroscience, CNR, Milano, Italy.,Istituto Clinico Humanitas, IRCCS, Rozzano, Italy
| | | | - Annalisa Alfieri
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Costanza Angelini
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Federico Tommaso Bianchi
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy.,Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy
| | - Alessandro Morellato
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Andrea Marcantoni
- Department of Drug Science, University of Torino, Torino, Italy.,NIS Centre of Excellence, Torino, Italy
| | - Marco Sassoè-Pognetto
- Department of Neuroscience, University of Torino, Torino, Italy.,National Institute of Neuroscience-Italy, Torino, Italy
| | | | - Latefa Yekhlef
- Division of Neuroscience, San Raffaele Scientific Institute, Milano, Italy
| | - Maurizio Giustetto
- Department of Neuroscience, University of Torino, Torino, Italy.,National Institute of Neuroscience-Italy, Torino, Italy
| | - Stefano Taverna
- Division of Neuroscience, San Raffaele Scientific Institute, Milano, Italy
| | - Valentina Carabelli
- Department of Drug Science, University of Torino, Torino, Italy.,NIS Centre of Excellence, Torino, Italy
| | - Michela Matteoli
- Institute of Neuroscience, CNR, Milano, Italy.,Istituto Clinico Humanitas, IRCCS, Rozzano, Italy
| | - Emilio Carbone
- Department of Drug Science, University of Torino, Torino, Italy.,NIS Centre of Excellence, Torino, Italy
| | - Emilia Turco
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Paola Defilippi
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
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13
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Lu CQ, Xu W, Zeng CH, Ge LY, Wang YC, Meng XP, Yu Q, Wu D, Ju S. Altered amplitude of low-frequency fluctuation in basal ganglia correlates to pulmonary ventilation function in COPD patients: A resting-state fMRI study. Brain Behav 2019; 9:e01336. [PMID: 31140760 PMCID: PMC6625472 DOI: 10.1002/brb3.1336] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/01/2019] [Accepted: 05/06/2019] [Indexed: 01/19/2023] Open
Abstract
INTRODUCTION Patients under chronic obstructive pulmonary disease (COPD) has been reported to be associated with a higher prevalence of cognitive impairment (CI). However, it is still largely unknown whether the aberrant resting-state spontaneous neuronal activity pattern reflected by the amplitude of low-frequency fluctuation (ALFF) analysis will be associated with the CI in COPD patients. MATERIALS A total of 28 COPD patients and 26 healthy controls were enrolled in this study. Of all the subjects, structural and functional MRI data, spirometry tests performance and neuropsychological assessments of different cognitive domains were collected. Voxel-based two-sample t tests were used to detect brain regions showing differences in the ALFF value between COPD patients and healthy controls. An additional fMRI runs with supplementary oxygen delivery were employed to explore the impact of elevated partial pressure of oxygen (PaO2 ) or moderate hyperoxia on ALFF in COPD patients and healthy controls respectively. RESULTS More extensive white matter lesion was detected in COPD patients. COPD patients exhibit decreased ALFF value in bilateral basal ganglia areas and right thalamus, and aberrant ALFF value is correlated with PaO2 and pulmonary ventilation function (FEV1%pred). COPD patients performed worse in the Digit Span Test (reverse), Digit Symbol Substitution Test, Trail-making test (A and B) than controls. After supplementary oxygen inhalation, the ALFF value of basal ganglia and right thalamus significantly increased in the controls, but not in the COPD patients. CONCLUSIONS COPD patients mainly exhibit impaired executive function but not long-term memory in cognitive function assessment. Aberrant ALFF alteration in the deep brain may be directly related to lower PaO2 in COPD patients.
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Affiliation(s)
- Chun-Qiang Lu
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Weiwei Xu
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Chu-Hui Zeng
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Lu-Yao Ge
- Department of Respirology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Yuan-Cheng Wang
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Xiang-Pan Meng
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Qian Yu
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Di Wu
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Shenghong Ju
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
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14
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Gavello D, Calorio C, Franchino C, Cesano F, Carabelli V, Carbone E, Marcantoni A. Early Alterations of Hippocampal Neuronal Firing Induced by Abeta42. Cereb Cortex 2019; 28:433-446. [PMID: 27999123 DOI: 10.1093/cercor/bhw377] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Indexed: 12/11/2022] Open
Abstract
We studied the effect of Amyloid β 1-42 oligomers (Abeta42) on Ca2+ dependent excitability profile of hippocampal neurons. Abeta42 is one of the Amyloid beta peptides produced by the proteolytic processing of the amyloid precursor protein and participates in the initiating event triggering the progressive dismantling of synapses and neuronal circuits. Our experiments on cultured hippocampal network reveal that Abeta42 increases intracellular Ca2+ concentration by 46% and inhibits firing discharge by 19%. More precisely, Abeta42 differently regulates ryanodine (RyRs), NMDA receptors (NMDARs), and voltage gated calcium channels (VGCCs) by increasing Ca2+ release through RyRs and inhibiting Ca2+ influx through NMDARs and VGCCs. The overall increased intracellular Ca2+ concentration causes stimulation of K+ current carried by big conductance Ca2+ activated potassium (BK) channels and hippocampal network firing inhibition. We conclude that Abeta42 alters neuronal function by means of at least 4 main targets: RyRs, NMDARs, VGCCs, and BK channels. The development of selective modulators of these channels may in turn be useful for developing effective therapies that could enhance the quality of life of AD patients during the early onset of the pathology.
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Affiliation(s)
- Daniela Gavello
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
| | - Chiara Calorio
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
| | - Claudio Franchino
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
| | - Federico Cesano
- Department of Chemistry Via Pietro Giuria 7, Torino University, 10125 Torino, Italy
| | - Valentina Carabelli
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
| | - Emilio Carbone
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
| | - Andrea Marcantoni
- Department of Drug Science and Technology, Torino University, Corso Raffaello 30, 10125 Torino, Italy
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15
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Tomagra G, Picollo F, Battiato A, Picconi B, De Marchis S, Pasquarelli A, Olivero P, Marcantoni A, Calabresi P, Carbone E, Carabelli V. Quantal Release of Dopamine and Action Potential Firing Detected in Midbrain Neurons by Multifunctional Diamond-Based Microarrays. Front Neurosci 2019; 13:288. [PMID: 31024230 PMCID: PMC6465646 DOI: 10.3389/fnins.2019.00288] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/11/2019] [Indexed: 12/20/2022] Open
Abstract
Micro-Graphitic Single Crystal Diamond Multi Electrode Arrays (μG-SCD-MEAs) have so far been used as amperometric sensors to detect catecholamines from chromaffin cells and adrenal gland slices. Besides having time resolution and sensitivity that are comparable with carbon fiber electrodes, that represent the gold standard for amperometry, μG-SCD-MEAs also have the advantages of simultaneous multisite detection, high biocompatibility and implementation of amperometric/potentiometric protocols, aimed at monitoring exocytotic events and neuronal excitability. In order to adapt diamond technology to record neuronal activity, the μG-SCD-MEAs in this work have been interfaced with cultured midbrain neurons to detect electrical activity as well as quantal release of dopamine (DA). μG-SCD-MEAs are based on graphitic sensing electrodes that are embedded into the diamond matrix and are fabricated using MeV ion beam lithography. Two geometries have been adopted, with 4 × 4 and 8 × 8 microelectrodes (20 μm × 3.5 μm exposed area, 200 μm spacing). In the amperometric configuration, the 4 × 4 μG-SCD-MEAs resolved quantal exocytosis from midbrain dopaminergic neurons. KCl-stimulated DA release occurred as amperometric spikes of 15 pA amplitude and 0.5 ms half-width, at a mean frequency of 0.4 Hz. When used as potentiometric multiarrays, the 8 × 8 μG-SCD-MEAs detected the spontaneous firing activity of midbrain neurons. Extracellularly recorded action potentials (APs) had mean amplitude of ∼-50 μV and occurred at a mean firing frequency of 0.7 Hz in 67% of neurons, while the remaining fired at 6.8 Hz. Comparable findings were observed using conventional MEAs (0.9 and 6.4 Hz, respectively). To test the reliability of potentiometric recordings with μG-SCD-MEAs, the D2-autoreceptor modulation of firing was investigated by applying levodopa (L-DOPA, 20 μM), and comparing μG-SCD-MEAs, conventional MEAs and current-clamp recordings. In all cases, L-DOPA reduced the spontaneous spiking activity in most neurons by 70%, while the D2-antagonist sulpiride reversed this effect. Cell firing inhibition was generally associated with increased APs amplitude. A minority of neurons was either insensitive to, or potentiated by L-DOPA, suggesting that AP recordings originate from different midbrain neuronal subpopulations and reveal different modulatory pathways. Our data demonstrate, for the first time, that μG-SCD-MEAs are multi-functional biosensors suitable to resolve real-time DA release and AP firing in in vitro neuronal networks.
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Affiliation(s)
- Giulia Tomagra
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
| | - Federico Picollo
- Department of Physics and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy.,Istituto Nazionale di Fisica Nucleare - Sezione di Torino, Turin, Italy
| | - Alfio Battiato
- Istituto Nazionale di Fisica Nucleare - Sezione di Torino, Turin, Italy
| | - Barbara Picconi
- Experimental Neurophysiology Laboratory, IRCCS San Raffaele Pisana, University San Raffaele, Rome, Italy.,University San Raffaele, Rome, Italy
| | - Silvia De Marchis
- Department of Life Sciences and Systems Biology and "NICO" Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Turin, Italy
| | | | - Paolo Olivero
- Department of Physics and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy.,Istituto Nazionale di Fisica Nucleare - Sezione di Torino, Turin, Italy
| | - Andrea Marcantoni
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
| | - Paolo Calabresi
- Neurological Clinic, Department of Medicine, Hospital Santa Maria della Misericordia, University of Perugia, Perugia, Italy
| | - Emilio Carbone
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
| | - Valentina Carabelli
- Department of Drug and Science Technology and "NIS" Inter-departmental Centre, University of Torino, Turin, Italy
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16
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Guarina L, Calorio C, Gavello D, Moreva E, Traina P, Battiato A, Ditalia Tchernij S, Forneris J, Gai M, Picollo F, Olivero P, Genovese M, Carbone E, Marcantoni A, Carabelli V. Nanodiamonds-induced effects on neuronal firing of mouse hippocampal microcircuits. Sci Rep 2018; 8:2221. [PMID: 29396456 PMCID: PMC5797106 DOI: 10.1038/s41598-018-20528-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 01/11/2018] [Indexed: 01/31/2023] Open
Abstract
Fluorescent nanodiamonds (FND) are carbon-based nanomaterials that can efficiently incorporate optically active photoluminescent centers such as the nitrogen-vacancy complex, thus making them promising candidates as optical biolabels and drug-delivery agents. FNDs exhibit bright fluorescence without photobleaching combined with high uptake rate and low cytotoxicity. Focusing on FNDs interference with neuronal function, here we examined their effect on cultured hippocampal neurons, monitoring the whole network development as well as the electrophysiological properties of single neurons. We observed that FNDs drastically decreased the frequency of inhibitory (from 1.81 Hz to 0.86 Hz) and excitatory (from 1.61 to 0.68 Hz) miniature postsynaptic currents, and consistently reduced action potential (AP) firing frequency (by 36%), as measured by microelectrode arrays. On the contrary, bursts synchronization was preserved, as well as the amplitude of spontaneous inhibitory and excitatory events. Current-clamp recordings revealed that the ratio of neurons responding with AP trains of high-frequency (fast-spiking) versus neurons responding with trains of low-frequency (slow-spiking) was unaltered, suggesting that FNDs exerted a comparable action on neuronal subpopulations. At the single cell level, rapid onset of the somatic AP (“kink”) was drastically reduced in FND-treated neurons, suggesting a reduced contribution of axonal and dendritic components while preserving neuronal excitability.
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Affiliation(s)
- L Guarina
- Department of Drug Science and Technology, "NIS" inter-departmental centre, University of Torino, Corso Raffaello 30, 10125, Torino, Italy
| | - C Calorio
- Department of Drug Science and Technology, "NIS" inter-departmental centre, University of Torino, Corso Raffaello 30, 10125, Torino, Italy
| | - D Gavello
- Department of Drug Science and Technology, "NIS" inter-departmental centre, University of Torino, Corso Raffaello 30, 10125, Torino, Italy
| | - E Moreva
- Istituto Nazionale Ricerca Metrologica, Strada delle Cacce 91, 10135, Torino, Italy
| | - P Traina
- Istituto Nazionale Ricerca Metrologica, Strada delle Cacce 91, 10135, Torino, Italy
| | - A Battiato
- Istituto Nazionale di Fisica Nucleare, sezione di Torino, Via P. Giuria 1, 10125, Torino, Italy
| | - S Ditalia Tchernij
- Department of Physics and "NIS" inter-departmental centre, University of Torino, Via P. Giuria 1, 10125, Torino, Italy.,Istituto Nazionale di Fisica Nucleare, sezione di Torino, Via P. Giuria 1, 10125, Torino, Italy
| | - J Forneris
- Istituto Nazionale di Fisica Nucleare, sezione di Torino, Via P. Giuria 1, 10125, Torino, Italy
| | - M Gai
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126, Torino, Italy
| | - F Picollo
- Department of Physics and "NIS" inter-departmental centre, University of Torino, Via P. Giuria 1, 10125, Torino, Italy.,Istituto Nazionale di Fisica Nucleare, sezione di Torino, Via P. Giuria 1, 10125, Torino, Italy
| | - P Olivero
- Department of Physics and "NIS" inter-departmental centre, University of Torino, Via P. Giuria 1, 10125, Torino, Italy.,Istituto Nazionale di Fisica Nucleare, sezione di Torino, Via P. Giuria 1, 10125, Torino, Italy
| | - M Genovese
- Istituto Nazionale Ricerca Metrologica, Strada delle Cacce 91, 10135, Torino, Italy.,Istituto Nazionale di Fisica Nucleare, sezione di Torino, Via P. Giuria 1, 10125, Torino, Italy
| | - E Carbone
- Department of Drug Science and Technology, "NIS" inter-departmental centre, University of Torino, Corso Raffaello 30, 10125, Torino, Italy
| | - A Marcantoni
- Department of Drug Science and Technology, "NIS" inter-departmental centre, University of Torino, Corso Raffaello 30, 10125, Torino, Italy
| | - V Carabelli
- Department of Drug Science and Technology, "NIS" inter-departmental centre, University of Torino, Corso Raffaello 30, 10125, Torino, Italy.
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17
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McGregor G, Harvey J. Food for thought: Leptin regulation of hippocampal function and its role in Alzheimer's disease. Neuropharmacology 2017; 136:298-306. [PMID: 28987937 DOI: 10.1016/j.neuropharm.2017.09.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 09/27/2017] [Accepted: 09/30/2017] [Indexed: 01/08/2023]
Abstract
Accumulating evidence indicates that diet and body weight are important factors associated with Alzheimer's disease (AD), with a significant increase in AD risk linked to mid-life obesity, and weight loss frequently occurring in the early stages of AD. This has fuelled interest in the hormone leptin, as it is an important hypothalamic regulator of food intake and body weight, but leptin also markedly influences the functioning of the hippocampus; a key brain region that degenerates in AD. Increasing evidence indicates that leptin has cognitive enhancing properties as it facilitates the cellular events that underlie hippocampal-dependent learning and memory. However, significant reductions in leptin's capacity to regulate hippocampal synaptic function occurs with age and dysfunctions in the leptin system are associated with an increased risk of AD. Moreover, leptin is a potential novel target in AD as leptin treatment has beneficial effects in various models of AD. Here we summarise recent advances in leptin neurobiology with particular focus on regulation of hippocampal synaptic function by leptin and the implications of this for neurodegenerative disorders like AD. This article is part of the Special Issue entitled 'Metabolic Impairment as Risk Factors for Neurodegenerative Disorders.'
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Affiliation(s)
- Gemma McGregor
- Division of Neuroscience, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, United Kingdom
| | - Jenni Harvey
- Division of Neuroscience, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, United Kingdom.
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18
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Roles of Na +, Ca 2+, and K + channels in the generation of repetitive firing and rhythmic bursting in adrenal chromaffin cells. Pflugers Arch 2017; 470:39-52. [PMID: 28776261 DOI: 10.1007/s00424-017-2048-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 07/23/2017] [Indexed: 12/30/2022]
Abstract
Adrenal chromaffin cells (CCs) are the main source of circulating catecholamines (CAs) that regulate the body response to stress. Release of CAs is controlled neurogenically by the activity of preganglionic sympathetic neurons through trains of action potentials (APs). APs in CCs are generated by robust depolarization following the activation of nicotinic and muscarinic receptors that are highly expressed in CCs. Bovine, rat, mouse, and human CCs also express a composite array of Na+, K+, and Ca2+ channels that regulate the resting potential, shape the APs, and set the frequency of AP trains. AP trains of increasing frequency induce enhanced release of CAs. If the primary role of CCs is simply to relay preganglionic nerve commands to CA secretion, why should they express such a diverse set of ion channels? An answer to this comes from recent observations that, like in neurons, CCs undergo complex firing patterns of APs suggesting the existence of an intrinsic CC excitability (non-neurogenically controlled). Recent work has shown that CCs undergo occasional or persistent burst firing elicited by altered physiological conditions or deletion of pore-regulating auxiliary subunits. In this review, we aim to give a rationale to the role of the many ion channel types regulating CC excitability. We will first describe their functional properties and then analyze how they contribute to pacemaking, AP shape, and burst waveforms. We will also furnish clear indications on missing ion conductances that may be involved in pacemaking and highlight the contribution of the crucial channels involved in burst firing.
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19
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Zhang J, Chen J, Fan C, Li J, Lin J, Yang T, Fan M. Alteration of Spontaneous Brain Activity After Hypoxia-Reoxygenation: A Resting-State fMRI Study. High Alt Med Biol 2017; 18:20-26. [PMID: 28266873 DOI: 10.1089/ham.2016.0083] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Zhang, Jiaxing, Ji Chen, Cunxiu Fan, Jinqiang Li, Jianzhong Lin, Tianhe Yang, and Ming Fan. Alteration of spontaneous brain activity after hypoxia-reoxygenation: A resting-state fMRI study. High Alt Med Biol. 18:20-26, 2017.-The present study was designed to investigate the effect of hypoxia-reoxygenation on the spontaneous neuronal activity in brain. Sixteen sea-level (SL) soldiers (20.5 ± 0.7 years), who garrisoned the frontiers in high altitude (HA) (2300-4400 m) for two years and subsequently descended to sea level for one to seven days, were recruited. Control group consisted of 16 matched SL natives. The amplitude of low-frequency fluctuations (ALFF) of regional brain functional magnetic resonance imaging signal in resting state and functional connectivity (FC) between brain regions was analyzed. HA subjects showed significant increases of ALFF at several sites within the bilateral occipital cortices and significant decreases of ALFF in the right anterior insula and extending to the caudate, putamen, inferior frontal orbital cortex, temporal pole, and superior temporal gyrus; lower ALFF values in the right insula were positively correlated with low respiratory measurements. The right insula in HA subjects had increases of FC with the right superior temporal gyrus, postcentral gyrus, rolandic operculum, supramarginal gyrus, and inferior frontal triangular area. We thus demonstrated that hypoxia-reoxygenation had influence on the spontaneous neuronal activity in brain. The decrease of insular neuronal activity may be related to the reduction of ventilatory drive, while the increase of FC with insula may indicate a central compensation.
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Affiliation(s)
- Jiaxing Zhang
- 1 Department of Physiology, Medical College of Xiamen University , Xiamen, China
| | - Ji Chen
- 1 Department of Physiology, Medical College of Xiamen University , Xiamen, China
| | - Cunxiu Fan
- 1 Department of Physiology, Medical College of Xiamen University , Xiamen, China
| | - Jinqiang Li
- 2 Department of Clinical Psychology, Gulangyu Sanatorium of PLA , Xiamen, China
| | - Jianzhong Lin
- 3 Magnetic Resonance Center, Zhongshan Hospital Xiamen University , Xiamen, China
| | - Tianhe Yang
- 3 Magnetic Resonance Center, Zhongshan Hospital Xiamen University , Xiamen, China
| | - Ming Fan
- 4 Department of Cognitive Sciences, Institute of Basic Medical Sciences , Beijing, China
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Carabelli V, Marcantoni A, Picollo F, Battiato A, Bernardi E, Pasquarelli A, Olivero P, Carbone E. Planar Diamond-Based Multiarrays to Monitor Neurotransmitter Release and Action Potential Firing: New Perspectives in Cellular Neuroscience. ACS Chem Neurosci 2017; 8:252-264. [PMID: 28027435 DOI: 10.1021/acschemneuro.6b00328] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
High biocompatibility, outstanding electrochemical responsiveness, inertness, and transparency make diamond-based multiarrays (DBMs) first-rate biosensors for in vitro detection of electrochemical and electrical signals from excitable cells together, with potential for in vivo applications as neural interfaces and prostheses. Here, we will review the electrochemical and physical properties of various DBMs and how these devices have been employed for recording released neurotransmitter molecules and all-or-none action potentials from living cells. Specifically, we will overview how DBMs can resolve localized exocytotic events from subcellular compartments using high-density microelectrode arrays (MEAs), or monitoring oxidizable neurotransmitter release from populations of cells in culture and tissue slices using low-density MEAs. Interfacing DBMs with excitable cells is currently leading to the promising opportunity of recording electrical signals as well as creating neuronal interfaces through the same device. Given the recent increasingly growing development of newly available DBMs of various geometries to monitor electrical activity and neurotransmitter release in a variety of excitable and neuronal tissues, the discussion will be limited to planar DBMs.
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Affiliation(s)
- Valentina Carabelli
- Consorzio Nazionale Interuniversitario per le Scienze fisiche della Materia (CNISM), 10125 Torino Unit, Italy
| | - Andrea Marcantoni
- Consorzio Nazionale Interuniversitario per le Scienze fisiche della Materia (CNISM), 10125 Torino Unit, Italy
| | - Federico Picollo
- Consorzio Nazionale Interuniversitario per le Scienze fisiche della Materia (CNISM), 10125 Torino Unit, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), 10125 sez. Torino, Italy
| | - Alfio Battiato
- Consorzio Nazionale Interuniversitario per le Scienze fisiche della Materia (CNISM), 10125 Torino Unit, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), 10125 sez. Torino, Italy
| | - Ettore Bernardi
- Consorzio Nazionale Interuniversitario per le Scienze fisiche della Materia (CNISM), 10125 Torino Unit, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), 10125 sez. Torino, Italy
| | - Alberto Pasquarelli
- Institute
of Electron Devices and Circuits, Ulm University, 89081 Ulm, Germany
| | - Paolo Olivero
- Consorzio Nazionale Interuniversitario per le Scienze fisiche della Materia (CNISM), 10125 Torino Unit, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), 10125 sez. Torino, Italy
| | - Emilio Carbone
- Consorzio Nazionale Interuniversitario per le Scienze fisiche della Materia (CNISM), 10125 Torino Unit, Italy
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21
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Zamboni V, Armentano M, Sarò G, Ciraolo E, Ghigo A, Germena G, Umbach A, Valnegri P, Passafaro M, Carabelli V, Gavello D, Bianchi V, D'Adamo P, de Curtis I, El-Assawi N, Mauro A, Priano L, Ferri N, Hirsch E, Merlo GR. Disruption of ArhGAP15 results in hyperactive Rac1, affects the architecture and function of hippocampal inhibitory neurons and causes cognitive deficits. Sci Rep 2016; 6:34877. [PMID: 27713499 PMCID: PMC5054378 DOI: 10.1038/srep34877] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 09/19/2016] [Indexed: 11/12/2022] Open
Abstract
During brain development, the small GTPases Rac1/Rac3 play key roles in neuronal migration, neuritogenesis, synaptic formation and plasticity, via control of actin cytoskeleton dynamic. Their activity is positively and negatively regulated by GEFs and GAPs molecules, respectively. However their in vivo roles are poorly known. The ArhGAP15 gene, coding for a Rac-specific GAP protein, is expressed in both excitatory and inhibitory neurons of the adult hippocampus, and its loss results in the hyperactivation of Rac1/Rac3. In the CA3 and dentate gyrus (DG) regions of the ArhGAP15 mutant hippocampus the CR+, PV+ and SST+ inhibitory neurons are reduced in number, due to reduced efficiency and directionality of their migration, while pyramidal neurons are unaffected. Loss of ArhGAP15 alters neuritogenesis and the balance between excitatory and inhibitory synapses, with a net functional result consisting in increased spike frequency and bursts, accompanied by poor synchronization. Thus, the loss of ArhGAP15 mainly impacts on interneuron-dependent inhibition. Adult ArhGAP15−/− mice showed defective hippocampus-dependent functions such as working and associative memories. These findings indicate that a normal architecture and function of hippocampal inhibitory neurons is essential for higher hippocampal functions, and is exquisitely sensitive to ArhGAP15-dependent modulation of Rac1/Rac3.
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Affiliation(s)
- Valentina Zamboni
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Maria Armentano
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Gabriella Sarò
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Elisa Ciraolo
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Alessandra Ghigo
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Giulia Germena
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Alessandro Umbach
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | | | | | | | | | - Veronica Bianchi
- IRCSS San Raffaele Scientific Institute and San Raffaele University, Division of Neuroscience, Milano, Italy
| | - Patrizia D'Adamo
- IRCSS San Raffaele Scientific Institute and San Raffaele University, Division of Neuroscience, Milano, Italy
| | - Ivan de Curtis
- IRCSS San Raffaele Scientific Institute and San Raffaele University, Division of Neuroscience, Milano, Italy
| | - Nadia El-Assawi
- Department of Neurosciences, University of Turin &Div. of Neurology and Neurorehabilitation, S.Giuseppe Hospital, Istituto Auxologico Italiano IRCCS, Piancavallo (VB), Italy
| | - Alessandro Mauro
- Department of Neurosciences, University of Turin &Div. of Neurology and Neurorehabilitation, S.Giuseppe Hospital, Istituto Auxologico Italiano IRCCS, Piancavallo (VB), Italy
| | - Lorenzo Priano
- Department of Neurosciences, University of Turin &Div. of Neurology and Neurorehabilitation, S.Giuseppe Hospital, Istituto Auxologico Italiano IRCCS, Piancavallo (VB), Italy
| | - Nicola Ferri
- Department of Pharmaceutical and Pharmacological Science, University of Padova, Italy
| | - Emilio Hirsch
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
| | - Giorgio R Merlo
- Department of Molecular Biotechnologies and Health Sciences, University of Torino, Italy
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Subconvulsant doses of pentylenetetrazol uncover the epileptic phenotype of cultured synapsin-deficient Helix serotonergic neurons in the absence of excitatory and inhibitory inputs. Epilepsy Res 2016; 127:241-251. [PMID: 27639349 DOI: 10.1016/j.eplepsyres.2016.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 08/24/2016] [Accepted: 09/06/2016] [Indexed: 11/21/2022]
Abstract
Synapsins are a family of presynaptic proteins related to several processes of synaptic functioning. A variety of reports have linked mutations in synapsin genes with the development of epilepsy. Among the proposed mechanisms, a main one is based on the synapsin-mediated imbalance towards network hyperexcitability due to differential effects on neurotransmitter release in GABAergic and glutamatergic synapses. Along this line, a non-synaptic effect of synapsin depletion increasing neuronal excitability has recently been described in Helix neurons. To further investigate this issue, we examined the effect of synapsin knock-down on the development of pentylenetetrazol (PTZ)-induced epileptic-like activity using single neurons or isolated monosynaptic circuits reconstructed on microelectrode arrays (MEAs). Compared to control neurons, synapsin-silenced neurons showed a lower threshold for the development of epileptic-like activity and prolonged periods of activity, together with the occurrence of spontaneous firing after recurrent PTZ-induced epileptic-like activity. These findings highlight the crucial role of synapsin on neuronal excitability regulation in the absence of inhibitory or excitatory inputs.
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23
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Zhang J, Chen J, Yu Q, Fan C, Zhang R, Lin J, Yang T, Fan M. Alteration of spontaneous brain activity in COPD patients. Int J Chron Obstruct Pulmon Dis 2016; 11:1713-9. [PMID: 27555761 PMCID: PMC4968669 DOI: 10.2147/copd.s110089] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Background and objective Airflow limitation in chronic obstructive pulmonary disease (COPD) results in a decrease in oxygen transport to the brain. The aim of the present study was to explore the alteration of spontaneous brain activity induced by hypoxia in patients with COPD. Patients and methods Twenty-five stable patients with COPD and 25 matching healthy volunteers were investigated. Amplitude of low-frequency fluctuation (ALFF) of blood oxygenation level-dependent signal at resting state in the brain was analyzed using functional magnetic resonance imaging. Results Whole-brain analysis using functional magnetic resonance imaging revealed significant decreases in ALFF in the bilateral posterior cingulate gyri and right lingual gyrus and an increase in ALFF in the left postcentral gyrus of patients with COPD. After controlling for SaO2, patients with COPD only showed an increase in ALFF in the left postcentral gyrus. Region of interest analysis showed a decrease in ALFF in the left precentral gyrus and an increase in ALFF in the left caudate nucleus of patients with COPD. In all subjects, ALFF in the bilateral posterior cingulate gyri and right lingual gyrus showed positive correlations with visual reproduction. Conclusion We demonstrated abnormal spontaneous brain activity of patients with COPD, which may have a pathophysiologic meaning.
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Affiliation(s)
- Jiaxing Zhang
- Department of Physiology, Medical College of Xiamen University, Xiangan
| | - Ji Chen
- Department of Physiology, Medical College of Xiamen University, Xiangan
| | - Qian Yu
- Department of Physiology, Medical College of Xiamen University, Xiangan
| | - Cunxiu Fan
- Department of Physiology, Medical College of Xiamen University, Xiangan
| | - Ran Zhang
- Department of Physiology, Medical College of Xiamen University, Xiangan
| | - Jianzhong Lin
- Magnetic Resonance Center, Department of Radiology, Zhongshan Hospital Xiamen University, Xiamen, Fujian
| | - Tianhe Yang
- Magnetic Resonance Center, Department of Radiology, Zhongshan Hospital Xiamen University, Xiamen, Fujian
| | - Ming Fan
- Department of Cognitive Sciences, Institute of Basic Medical Sciences, Beijing, People's Republic of China
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24
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Gavello D, Carbone E, Carabelli V. Leptin-mediated ion channel regulation: PI3K pathways, physiological role, and therapeutic potential. Channels (Austin) 2016; 10:282-96. [PMID: 27018500 DOI: 10.1080/19336950.2016.1164373] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Leptin is produced by adipose tissue and identified as a "satiety signal," informing the brain when the body has consumed enough food. Specific areas of the hypothalamus express leptin receptors (LEPRs) and are the primary site of leptin action for body weight regulation. In response to leptin, appetite is suppressed and energy expenditure allowed. Beside this hypothalamic action, leptin targets other brain areas in addition to neuroendocrine cells. LEPRs are expressed also in the hippocampus, neocortex, cerebellum, substantia nigra, pancreatic β-cells, and chromaffin cells of the adrenal gland. It is intriguing how leptin is able to activate different ionic conductances, thus affecting excitability, synaptic plasticity and neurotransmitter release, depending on the target cell. Most of the intracellular pathways activated by leptin and directed to ion channels involve PI3K, which in turn phosphorylates different downstream substrates, although parallel pathways involve AMPK and MAPK. In this review we will describe the effects of leptin on BK, KATP, KV, CaV, TRPC, NMDAR and AMPAR channels and clarify the landscape of pathways involved. Given the ability of leptin to influence neuronal excitability and synaptic plasticity by modulating ion channels activity, we also provide a short overview of the growing potentiality of leptin as therapeutic agent for treating neurological disorders.
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Affiliation(s)
- Daniela Gavello
- a Department of Drug Science , Lab of Cellular Physiology and Molecular Neuroscience, NIS Center of Excellence, University of Torino , Torino , Italy
| | - Emilio Carbone
- a Department of Drug Science , Lab of Cellular Physiology and Molecular Neuroscience, NIS Center of Excellence, University of Torino , Torino , Italy
| | - Valentina Carabelli
- a Department of Drug Science , Lab of Cellular Physiology and Molecular Neuroscience, NIS Center of Excellence, University of Torino , Torino , Italy
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25
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An improved functional assay for rapid detection of marine toxins, saxitoxin and brevetoxin using a portable cardiomyocyte-based potential biosensor. Biosens Bioelectron 2015; 72:10-7. [DOI: 10.1016/j.bios.2015.04.028] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 03/31/2015] [Accepted: 04/12/2015] [Indexed: 11/21/2022]
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26
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Gavello D, Vandael D, Gosso S, Carbone E, Carabelli V. Dual action of leptin on rest-firing and stimulated catecholamine release via phosphoinositide 3-kinase-driven BK channel up-regulation in mouse chromaffin cells. J Physiol 2015; 593:4835-53. [PMID: 26282459 DOI: 10.1113/jp271078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/12/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Leptin is an adipokine produced by the adipose tissue regulating body weight through its appetite-suppressing effect and, as such, exerts a relevant action on the adipo-adrenal axis. Leptin has a dual action on adrenal mouse chromaffin cells both at rest and during stimulation. At rest, the adipokine inhibits the spontaneous firing of most cells by enhancing the probability of BK channel opening through the phosphoinositide 3-kinase signalling cascade. This inhibitory effect is absent in db(-) /db(-) mice deprived of Ob receptors. During sustained stimulation, leptin preserves cell excitability by generating well-adapted action potential (AP) trains of lower frequency and broader width and increases catecholamine secretion by increasing the size of the ready-releasable pool and the rate of vesicle release. In conclusion, leptin dampens AP firing at rest but preserves AP firing and enhances catecholamine release during sustained stimulation, highlighting the importance of the adipo-adrenal axis in the leptin-mediated increase of sympathetic tone and catecholamine release. ABSTRACT Leptin is an adipokine produced by the adipose tissue regulating body weight through its appetite-suppressing effect. Besides being expressed in the hypothalamus and hippocampus, leptin receptors (ObRs) are also present in chromaffin cells of the adrenal medulla. In the present study, we report the effect of leptin on mouse chromaffin cell (MCC) functionality, focusing on cell excitability and catecholamine secretion. Acute application of leptin (1 nm) on spontaneously firing MCCs caused a slowly developing membrane hyperpolarization followed by complete blockade of action potential (AP) firing. This inhibitory effect at rest was abolished by the BK channel blocker paxilline (1 μm), suggesting the involvement of BK potassium channels. Single-channel recordings in 'perforated microvesicles' confirmed that leptin increased BK channel open probability without altering its unitary conductance. BK channel up-regulation was associated with the phosphoinositide 3-kinase (PI3K) signalling cascade because the PI3K specific inhibitor wortmannin (100 nm) fully prevented BK current increase. We also tested the effect of leptin on evoked AP firing and Ca(2+) -driven exocytosis. Although leptin preserves well-adapted AP trains of lower frequency, APs are broader and depolarization-evoked exocytosis is increased as a result of the larger size of the ready-releasable pool and higher frequency of vesicle release. The kinetics and quantal size of single secretory events remained unaltered. Leptin had no effect on firing and secretion in db(-) /db(-) mice lacking the ObR gene, confirming its specificity. In conclusion, leptin exhibits a dual action on MCC activity. It dampens AP firing at rest but preserves AP firing and increases catecholamine secretion during sustained stimulation, highlighting the importance of the adipo-adrenal axis in the leptin-mediated increase of sympathetic tone and catecholamine release.
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Affiliation(s)
- Daniela Gavello
- Department of Drug Science and Technology, University of Torino, Torino, Italy.,NIS Center, CNISM, University of Torino, Torino, Italy
| | - David Vandael
- Department of Drug Science and Technology, University of Torino, Torino, Italy.,NIS Center, CNISM, University of Torino, Torino, Italy.,Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg, Austria
| | - Sara Gosso
- Department of Drug Science and Technology, University of Torino, Torino, Italy.,NIS Center, CNISM, University of Torino, Torino, Italy
| | - Emilio Carbone
- Department of Drug Science and Technology, University of Torino, Torino, Italy.,NIS Center, CNISM, University of Torino, Torino, Italy
| | - Valentina Carabelli
- Department of Drug Science and Technology, University of Torino, Torino, Italy.,NIS Center, CNISM, University of Torino, Torino, Italy
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27
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Allio A, Calorio C, Franchino C, Gavello D, Carbone E, Marcantoni A. Bud extracts from Tilia tomentosa Moench inhibit hippocampal neuronal firing through GABAA and benzodiazepine receptors activation. JOURNAL OF ETHNOPHARMACOLOGY 2015; 172:288-296. [PMID: 26144285 DOI: 10.1016/j.jep.2015.06.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/10/2015] [Accepted: 06/14/2015] [Indexed: 06/04/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Tilia tomentosa Moench bud extracts (TTBEs) is used in traditional medicine for centuries as sedative compound. Different plants belonging to the Tilia genus have shown their efficacy in the treatment of anxiety but still little is known about the mechanism of action of their bud extracts. AIM OF THE STUDY To evaluate the action of TTBEs as anxiolytic and sedative compound on in vitro hippocampal neurons. MATERIAL AND METHODS The anxiolytic effect of TTBEs was assayed by testing the effects of these compounds on GABAA receptor-activated chloride current of hippocampal neurons by means of the patch-clamp technique and microelectrode-arrays (MEAs). RESULTS TTBEs acutely administered on mouse hippocampal neurons, activated a chloride current comparable to that measured in the presence of GABA (100 µM). Bicuculline (100 µM) and picrotoxin (100 µM) blocked about 90% of this current, while the remaining 10% was blocked by adding the benzodiazepine (BDZ) antagonist flumazenil (30 µM). Flumazenil alone blocked nearly 60% of the TTBEs activated current, suggesting that TTBEs binds to both GABAA and BDZ receptor sites. Application of high-doses of TTBEs on spontaneous active hippocampal neurons grown for 3 weeks on MEAs blocked the synchronous activity of these neurons. The effects were mimicked by GABA and prevented by picrotoxin (100µM) and flumazenil (30 µM). At minimal doses, TTBEs reduced the frequency of synchronized bursts and increased the cross-correlation index of synchronized neuronal firing. CONCLUSIONS Our data suggest that TTBEs mimics GABA and BDZ agonists by targeting hippocampal GABAergic synapses and inhibiting network excitability by increasing the strength of inhibitory synaptic outputs. Our results contribute toward the validation of TTBEs as effective sedative and anxiolytic compound.
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Affiliation(s)
- Arianna Allio
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
| | - Chiara Calorio
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
| | - Claudio Franchino
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
| | - Daniela Gavello
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
| | - Emilio Carbone
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
| | - Andrea Marcantoni
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
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28
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3D-nanostructured boron-doped diamond for microelectrode array neural interfacing. Biomaterials 2015; 53:173-83. [DOI: 10.1016/j.biomaterials.2015.02.021] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 01/21/2015] [Accepted: 02/01/2015] [Indexed: 01/10/2023]
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29
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Xie H, Zhang YQ, Pan XL, Wu SH, Chen X, Wang J, Liu H, Qian XZ, Liu ZG, Liu LJ. Decreased calcium-activated potassium channels by hypoxia causes abnormal firing in the spontaneous firing medial vestibular nuclei neurons. Eur Arch Otorhinolaryngol 2014; 272:2703-11. [PMID: 25173490 DOI: 10.1007/s00405-014-3158-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 06/15/2014] [Indexed: 12/20/2022]
Abstract
Vertebrobasilar insufficiency (VBI) presents complex varied clinical symptoms, including vertigo and hearing loss. Little is known, however, about how Ca(2+)-activated K(+) channel attributes to the medial vestibular nucleus (MVN) neural activity in VBI. To address this issue, we performed whole-cell patch clamp and quantitative polymerase chain reaction (qPCR) to examine the effects of hypoxia on neural activity and the changes of the large conductance Ca(2+) activated K(+) channels (BKCa channels) in the MVN neurons in brain slices of male C57BL/6 mice. Brief hypoxic stimuli of the brain slices containing MVN were administrated by switching the normoxic artificial cerebrospinal fluid (ACSF) equilibrated with 21% O2/5% CO2 to hypoxic ACSF equilibrated with 5% O2/5% CO2 (balance N2). 3-min hypoxia caused a depolarization in the resting membrane potential (RM) in 8/11 non-spontaneous firing MVN neurons. 60/72 spontaneous firing MVN neurons showed a dramatic increase in firing frequency and a depolarization in the RM following brief hypoxia. The amplitude of the afterhyperpolarization (AHPA) was significantly decreased in both type A and type B spontaneous firing MVN neurons. Hypoxia-induced firing response was alleviated by pretreatment with NS1619, a selective BKCa activator. Furthermore, brief hypoxia caused a decrease in the amplitude of iberiotoxin-sensitive outward currents and mRNA level of BKCa in MVN neurons. These results suggest that BKCa channels protect against abnormal MVN neuronal activity induced by hypoxia, and might be a key target for treatment of vertigo and hearing loss in VBI.
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Affiliation(s)
- Hong Xie
- Jingzhou Central Hospital, Jingzhou, 434020, People's Republic of China,
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30
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Nieto-Posadas A, Flores-Martínez E, Lorea-Hernández JJ, Rivera-Angulo AJ, Pérez-Ortega JE, Bargas J, Peña-Ortega F. Change in network connectivity during fictive-gasping generation in hypoxia: prevention by a metabolic intermediate. Front Physiol 2014; 5:265. [PMID: 25101002 PMCID: PMC4107943 DOI: 10.3389/fphys.2014.00265] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 06/25/2014] [Indexed: 11/13/2022] Open
Abstract
The neuronal circuit in charge of generating the respiratory rhythms, localized in the pre-Bötzinger complex (preBötC), is configured to produce fictive-eupnea during normoxia and reconfigures to produce fictive-gasping during hypoxic conditions in vitro. The mechanisms involved in such reconfiguration have been extensively investigated by cell-focused studies, but the actual changes at the network level remain elusive. Since a failure to generate gasping has been linked to Sudden Infant Death Syndrome (SIDS), the study of gasping generation and pharmacological approaches to promote it may have clinical relevance. Here, we study the changes in network dynamics and circuit reconfiguration that occur during the transition to fictive-gasping generation in the brainstem slice preparation by recording the preBötC with multi-electrode arrays and assessing correlated firing among respiratory neurons or clusters of respiratory neurons (multiunits). We studied whether the respiratory network reconfiguration in hypoxia involves changes in either the number of active respiratory elements, the number of functional connections among elements, or the strength of these connections. Moreover, we tested the influence of isocitrate, a Krebs cycle intermediate that has recently been shown to promote breathing, on the configuration of the preBötC circuit during normoxia and on its reconfiguration during hypoxia. We found that, in contrast to previous suggestions based on cell-focused studies, the number and the overall activity of respiratory neurons change only slightly during hypoxia. However, hypoxia induces a reduction in the strength of functional connectivity within the circuit without reducing the number of connections. Isocitrate prevented this reduction during hypoxia while increasing the strength of network connectivity. In conclusion, we provide an overview of the configuration of the respiratory network under control conditions and how it is reconfigured during fictive-gasping. Additionally, our data support the use of isocitrate to favor respiratory rhythm generation under normoxia and to prevent some of the changes in the respiratory network under hypoxic conditions.
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Affiliation(s)
- Andrés Nieto-Posadas
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México
| | - Ernesto Flores-Martínez
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México
| | - Jonathan-Julio Lorea-Hernández
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México
| | - Ana-Julia Rivera-Angulo
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México
| | - Jesús-Esteban Pérez-Ortega
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México México D.F., México
| | - José Bargas
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México México D.F., México
| | - Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Querétaro, México
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31
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Londraville RL, Macotela Y, Duff RJ, Easterling MR, Liu Q, Crespi EJ. Comparative endocrinology of leptin: assessing function in a phylogenetic context. Gen Comp Endocrinol 2014; 203:146-57. [PMID: 24525452 PMCID: PMC4128956 DOI: 10.1016/j.ygcen.2014.02.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 01/31/2014] [Accepted: 02/03/2014] [Indexed: 12/11/2022]
Abstract
As we approach the end of two decades of leptin research, the comparative biology of leptin is just beginning. We now have several leptin orthologs described from nearly every major clade among vertebrates, and are moving beyond gene descriptions to functional studies. Even at this early stage, it is clear that non-mammals display clear functional similarities and differences with their better-studied mammalian counterparts. This review assesses what we know about leptin function in mammals and non-mammals, and gives examples of how these data can inform leptin biology in humans.
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Affiliation(s)
- Richard L Londraville
- Department of Biology and Program in Integrated Biosciences, University of Akron, Akron, OH, USA.
| | - Yazmin Macotela
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Mexico
| | - Robert J Duff
- Department of Biology and Program in Integrated Biosciences, University of Akron, Akron, OH, USA
| | - Marietta R Easterling
- School of Biological Sciences and Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
| | - Qin Liu
- Department of Biology and Program in Integrated Biosciences, University of Akron, Akron, OH, USA
| | - Erica J Crespi
- School of Biological Sciences and Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
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32
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Mancini M, Soldovieri MV, Gessner G, Wissuwa B, Barrese V, Boscia F, Secondo A, Miceli F, Franco C, Ambrosino P, Canzoniero LMT, Bauer M, Hoshi T, Heinemann SH, Taglialatela M. Critical role of large-conductance calcium- and voltage-activated potassium channels in leptin-induced neuroprotection of N-methyl-d-aspartate-exposed cortical neurons. Pharmacol Res 2014; 87:80-6. [PMID: 24973659 DOI: 10.1016/j.phrs.2014.06.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 06/17/2014] [Accepted: 06/18/2014] [Indexed: 01/01/2023]
Abstract
In the present study, the neuroprotective effects of the adipokine leptin, and the molecular mechanism involved, have been studied in rat and mice cortical neurons exposed to N-methyl-d-aspartate (NMDA) in vitro. In rat cortical neurons, leptin elicited neuroprotective effects against NMDA-induced cell death, which were concentration-dependent (10-100 ng/ml) and largest when the adipokine was preincubated for 2h before the neurotoxic stimulus. In both rat and mouse cortical neurons, leptin-induced neuroprotection was fully antagonized by paxilline (Pax, 0.01-1 μM) and iberiotoxin (Ibtx, 1-100 nM), with EC50s of 38 ± 10 nM and 5 ± 2 nM for Pax and Ibtx, respectively, close to those reported for Pax- and Ibtx-induced Ca(2+)- and voltage-activated K(+) channels (Slo1 BK channels) blockade; the BK channel opener NS1619 (1-30 μM) induced a concentration-dependent protection against NMDA-induced excitotoxicity. Moreover, cortical neurons from mice lacking one or both alleles coding for Slo1 BK channel pore-forming subunits were insensitive to leptin-induced neuroprotection. Finally, leptin exposure dose-dependently (10-100 ng/ml) increased intracellular Ca(2+) levels in rat cortical neurons. In conclusion, our results suggest that Slo1 BK channel activation following increases in intracellular Ca(2+) levels is a critical step for leptin-induced neuroprotection in NMDA-exposed cortical neurons in vitro, thus highlighting leptin-based intervention via BK channel activation as a potential strategy to counteract neurodegenerative diseases.
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Affiliation(s)
- Maria Mancini
- Department of Medicine and Health Science, University of Molise, Campobasso, Italy; Department of Science and Technology, University of Sannio, Benevento, Italy; Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University and Jena University Hospital, Jena, Germany
| | | | - Guido Gessner
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University and Jena University Hospital, Jena, Germany
| | - Bianka Wissuwa
- Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Vincenzo Barrese
- Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Francesca Boscia
- Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Agnese Secondo
- Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Francesco Miceli
- Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Cristina Franco
- Department of Neuroscience, University of Naples "Federico II", Naples, Italy
| | - Paolo Ambrosino
- Department of Medicine and Health Science, University of Molise, Campobasso, Italy
| | | | - Michael Bauer
- Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Toshinori Hoshi
- Department of Physiology, University of Pennsylvania, Philadelphia, USA
| | - Stefan H Heinemann
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University and Jena University Hospital, Jena, Germany
| | - Maurizio Taglialatela
- Department of Medicine and Health Science, University of Molise, Campobasso, Italy; Department of Neuroscience, University of Naples "Federico II", Naples, Italy.
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33
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Nimmervoll B, Flucher BE, Obermair GJ. Dominance of P/Q-type calcium channels in depolarization-induced presynaptic FM dye release in cultured hippocampal neurons. Neuroscience 2013; 253:330-40. [PMID: 24012836 PMCID: PMC3824072 DOI: 10.1016/j.neuroscience.2013.08.052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 08/09/2013] [Accepted: 08/27/2013] [Indexed: 11/26/2022]
Abstract
We analyzed depolarization-induced synaptic FM dye release in hippocampal neurons. We pharmacologically isolated the contribution of voltage-gated Ca2+ channels. 85% of synapses utilize N- and P/Q-type channels, 15% only P/Q-type channels. In both groups of synapses release kinetics are determined by P/Q-type channels. We propose a more direct coupling of P/Q-type channels to synaptic release.
Neurotransmitter release probability is related by high power to the local concentration of calcium in presynaptic terminals, which in turn is controlled by voltage-gated calcium channels. P/Q- and N-type channels trigger synaptic transmission in the majority of neurons of the central nervous system. However, whether and under which conditions both channel types act cooperatively or independently is still insufficiently understood. Previous studies suggested either a dominance of N- or P/Q-type channels, or a synergistic action of both channels, depending on the experimental paradigms. Thus, to provide insight into the properties of neurotransmitter release in cultured mouse hippocampal neurons, we used quantitative analysis of FM dye release from presynaptic boutons induced by high potassium membrane depolarization. Increasing extracellular potassium concentrations revealed a sigmoid dependence of FM dye release to the stimulation strength. Individual and combined application of the P/Q- and N-type channel-specific blockers ω-agatoxin-IVA and ω-conotoxin-GVIA, respectively, allowed us to specifically isolate the contribution of both channel types to release triggered with 40 mM KCl. Analysis of the release kinetics and the fractional release amplitude demonstrate that, whereas in only 15% of the synapses release depended exclusively on P/Q-type channels, the majority of synapses (85%) contained both N- and P/Q-type channels. Nevertheless, the kinetics of FM dye release in synapses containing both channel types was determined by the P/Q-type channels. Together, our data suggest a more direct coupling of P/Q-type channels to synaptic release compared to N-type channels, which may explain the high prevalence of neurological P/Q-type channelopathies.
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Affiliation(s)
- B Nimmervoll
- Division of Physiology, Medical University Innsbruck, Fritz-Pregl-Str. 3, 6020 Innsbruck, Austria
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34
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Marwarha G, Ghribi O. Leptin signaling and Alzheimer's disease. AMERICAN JOURNAL OF NEURODEGENERATIVE DISEASE 2012; 1:245-265. [PMID: 23383396 PMCID: PMC3560472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 11/09/2012] [Indexed: 06/01/2023]
Abstract
Leptin, an adipocytokine produced in the peripheral system as well as in the brain, is implicated in obesity, food intake, glucose homeostasis, and energy expenditure. Leptin expression levels and signaling pathways may also be linked to the pathophysiology of neurodegenerative diseases including Alzheimer's disease. Epidemiological studies have demonstrated that higher circulating leptin levels are associated with lower risk of dementia including Alzheimer's disease, and lower circulating levels of leptin have been reported in patients with Alzheimer's disease. Leptin receptors are highly expressed in the hippocampus, a brain area involved in learning and memory and severely affected during the course of Alzheimer's disease. In laboratory studies, several in vivo and in vitro studies have shown that leptin supplementation decreases amyloid-β (Aβ) production and tau phosphorylation, two major biochemical events that play a key role in the pathogenesis of Alzheimer's disease. In this review, we will review the structure of leptin, the type of receptors of leptin in the brain, the various biological functions attributed to this adipocytokine, the signaling pathways that govern leptin actions, and the potential role of leptin in the pathophysiology of Alzheimer's disease. Leptin exerts its functions by binding to the leptin receptor (ObR). This binding can involve several signaling pathways including JAK/STAT pathway, ERK pathway and the PI3K/Akt/mTOR Pathway. Modulation of these pathways leads to the regulation of a multitude of functions that define the intricate involvement of leptin in various physiological tasks. In this review, we will specifically relate the potential involvement of leptin signaling in Alzheimer's disease based on work published by several laboratories including ours. All this work points to leptin as a possible target for developing supplementation therapies for reducing the progression of Alzheimer's disease.
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Affiliation(s)
- Gurdeep Marwarha
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota, School of Medicine and Health Sciences Grand Forks, North Dakota, 58202
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