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Kim HW, Yong H, Shea GKH. Blood-spinal cord barrier disruption in degenerative cervical myelopathy. Fluids Barriers CNS 2023; 20:68. [PMID: 37743487 PMCID: PMC10519090 DOI: 10.1186/s12987-023-00463-y] [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: 07/07/2023] [Accepted: 08/12/2023] [Indexed: 09/26/2023] Open
Abstract
Degenerative cervical myelopathy (DCM) is the most prevalent cause of spinal cord dysfunction in the aging population. Significant neurological deficits may result from a delayed diagnosis as well as inadequate neurological recovery following surgical decompression. Here, we review the pathophysiology of DCM with an emphasis on how blood-spinal cord barrier (BSCB) disruption is a critical yet neglected pathological feature affecting prognosis. In patients suffering from DCM, compromise of the BSCB is evidenced by elevated cerebrospinal fluid (CSF) to serum protein ratios and abnormal contrast-enhancement upon magnetic resonance imaging (MRI). In animal model correlates, there is histological evidence of increased extravasation of tissue dyes and serum contents, and pathological changes to the neurovascular unit. BSCB dysfunction is the likely culprit for ischemia-reperfusion injury following surgical decompression, which can result in devastating neurological sequelae. As there are currently no therapeutic approaches specifically targeting BSCB reconstitution, we conclude the review by discussing potential interventions harnessed for this purpose.
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Affiliation(s)
- Hyun Woo Kim
- Department of Orthopaedics and Traumatology, LKS Faulty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Hu Yong
- Department of Orthopaedics and Traumatology, LKS Faulty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Graham Ka Hon Shea
- Department of Orthopaedics and Traumatology, LKS Faulty of Medicine, The University of Hong Kong, Hong Kong, China.
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2
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Baxter PS, Dando O, Hardingham GE. Differential splicing choices made by neurons and astrocytes and their importance when investigating signal-dependent alternative splicing in neural cells. Front Mol Neurosci 2023; 16:1214439. [PMID: 37465362 PMCID: PMC10350517 DOI: 10.3389/fnmol.2023.1214439] [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: 04/29/2023] [Accepted: 06/15/2023] [Indexed: 07/20/2023] Open
Abstract
A variety of proteins can be encoded by a single gene via the differential splicing of exons. In neurons this form of alternative splicing can be controlled by activity-dependent calcium signaling, leading to the properties of proteins being altered, including ion channels, neurotransmitter receptors and synaptic cell adhesion molecules. The pre-synaptic cell adhesion molecule Neurexin 1 (Nrxn1) is alternatively spliced at splice-site 4 (SS4) which governs exon 22 inclusion (SS4+) and consequently postsynaptic NMDA receptor responses. Nrxn1 was reported to be subject to a delayed-onset shift in Nrxn1 SS4 splicing resulting in increased exon 22 inclusion, involving epigenetic mechanisms which, if disrupted, reduce memory stability. Exon inclusion at SS4 represented one of hundreds of exons reported to be subject to a genome-wide shift in fractional exon inclusion following membrane depolarization with high extracellular K+ that was delayed in onset. We report that high K+ does not increase the SS4+/SS4- ratio in cortical neurons, but does induce a delayed-onset NMDA receptor-dependent neuronal death. In mixed neuronal/astrocyte cultures this neuronal death results in an increase in the astrocyte: neuron ratio, and a misleading increase in SS4+/SS4- ratio attributable to astrocytes having a far higher SS4+/SS4- ratio than neurons, rather than any change in the neurons themselves. We reassessed the previously reported genome-wide delayed-onset shift in fractional exon inclusion after high K+ exposure. This revealed that the reported changes correlated strongly with differences in exon inclusion level between astrocytes and neurons, and was accompanied by a strong decrease in the ratio of neuron-specific: astrocyte-specific gene expression. As such, these changes can be explained by the neurotoxic nature of the stimulation paradigm, underlining the importance of NMDA receptor blockade when using high K+ depolarizing stimuli.
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Affiliation(s)
- Paul S. Baxter
- Edinburgh Medical School, UK Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
- Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, United Kingdom
| | - Owen Dando
- Edinburgh Medical School, UK Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
- Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, United Kingdom
| | - Giles E. Hardingham
- Edinburgh Medical School, UK Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
- Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, United Kingdom
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3
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Berntsen HF, Duale N, Bjørklund CG, Rangel-Huerta OD, Dyrberg K, Hofer T, Rakkestad KE, Østby G, Halsne R, Boge G, Paulsen RE, Myhre O, Ropstad E. Effects of a human-based mixture of persistent organic pollutants on the in vivo exposed cerebellum and cerebellar neuronal cultures exposed in vitro. ENVIRONMENT INTERNATIONAL 2021; 146:106240. [PMID: 33186814 DOI: 10.1016/j.envint.2020.106240] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/25/2020] [Accepted: 10/22/2020] [Indexed: 06/11/2023]
Abstract
Exposure to persistent organic pollutants (POPs), encompassing chlorinated (Cl), brominated (Br) and perfluoroalkyl acid (PFAA) compounds is associated with adverse neurobehaviour in humans and animals, and is observed to cause adverse effects in nerve cell cultures. Most studies focus on single POPs, whereas studies on effects of complex mixtures are limited. We examined the effects of a mixture of 29 persistent compounds (Cl + Br + PFAA, named Total mixture), as well as 6 sub-mixtures on in vitro exposed rat cerebellar granule neurons (CGNs). Protein expression studies of cerebella from in vivo exposed mice offspring were also conducted. The selection of chemicals for the POP mixture was based on compounds being prominent in food, breast milk or blood from the Scandinavian human population. The Total mixture and sub-mixtures containing PFAAs caused greater toxicity in rat CGNs than the single or combined Cl/Br sub-mixtures, with significant impact on viability from 500x human blood levels. The potencies for these mixtures based on LC50 values were Br + PFAA mixture > Total mixture > Cl + PFAA mixture > PFAA mixture. These mixtures also accelerated induced lipid peroxidation. Protection by the competitive N-methyl-D-aspartate (NMDA) receptor antagonist 3-((R)-2-Carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) indicated involvement of the NMDA receptor in PFAA and Total mixture-, but not Cl mixture-induced toxicity. Gene-expression studies in rat CGNs using a sub-toxic and marginally toxic concentration ((0.4 nM-5.5 µM) 333x and (1 nM-8.2 µM) 500x human blood levels) of the mixtures, revealed differential expression of genes involved in apoptosis, oxidative stress, neurotransmission and cerebellar development, with more genes affected at the marginally toxic concentration. The two important neurodevelopmental markers Pax6 and Grin2b were downregulated at 500x human blood levels, accompanied by decreases in PAX6 and GluN2B protein levels, in cerebellum of offspring mice from mothers exposed to the Total mixture throughout pregnancy and lactation. In rat CGNs, the glutathione peroxidase gene Prdx6 and the regulatory transmembrane glycoprotein gene Sirpa were highly upregulated at both concentrations. In conclusion, our results support that early-life exposure to mixtures of POPs can cause adverse neurodevelopmental effects.
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Affiliation(s)
- Hanne Friis Berntsen
- Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway; National Institute of Occupational Health, P.O. Box 5330 Majorstuen, 0304 Oslo, Norway.
| | - Nur Duale
- Section of Molecular Toxicology, Norwegian Institute of Public Health, N-0403 Oslo, Norway.
| | - Cesilie Granum Bjørklund
- Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway.
| | | | - Kine Dyrberg
- Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway.
| | - Tim Hofer
- Section of Toxicology and Risk Assessment, Norwegian Institute of Public Health, N-0403, Oslo, Norway.
| | - Kirsten Eline Rakkestad
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, P.O. Box 1072, Blindern, NO-0316 Oslo, Norway.
| | - Gunn Østby
- Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway.
| | - Ruth Halsne
- Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway.
| | - Gudrun Boge
- Department of Companion Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway.
| | - Ragnhild Elisabeth Paulsen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, P.O. Box 1072, Blindern, NO-0316 Oslo, Norway.
| | - Oddvar Myhre
- Section of Toxicology and Risk Assessment, Norwegian Institute of Public Health, N-0403, Oslo, Norway.
| | - Erik Ropstad
- Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway.
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4
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Berntsen HF, Moldes-Anaya A, Bjørklund CG, Ragazzi L, Haug TM, Strandabø RAU, Verhaegen S, Paulsen RE, Ropstad E, Tasker RA. Perfluoroalkyl acids potentiate glutamate excitotoxicity in rat cerebellar granule neurons. Toxicology 2020; 445:152610. [PMID: 33027616 DOI: 10.1016/j.tox.2020.152610] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/28/2020] [Accepted: 10/01/2020] [Indexed: 12/16/2022]
Abstract
Perfluoroalkyl acids (PFAAs) are persistent man-made chemicals, ubiquitous in nature and present in human samples. Although restrictions are being introduced, they are still used in industrial processes as well as in consumer products. PFAAs cross the blood-brain-barrier and have been observed to induce adverse neurobehavioural effects in humans and animals as well as adverse effects in neuronal in vitro studies. The sulfonated PFAA perfluorooctane sulfonic acid (PFOS), has been shown to induce excitotoxicity via the N-methyl-D-aspartate receptor (NMDA-R) in cultures of rat cerebellar granule neurons (CGNs). In the present study the aim was to further characterise PFOS-induced toxicity (1-60 μM) in rat CGNs, by examining interactions between PFOS and elements of glutamatergic signalling and excitotoxicity. Effects of the carboxylated PFAA, perfluorooctanoic acid (PFOA, 300-500 μM) on the same endpoints were also examined. During experiments in immature cultures at days in vitro (DIV) 8, PFOS increased both the potency and efficacy of glutamate, whereas in mature cultures at DIV 14 only increased potency was observed. PFOA also increased potency at DIV 14. PFOS-enhanced glutamate toxicity was further antagonised by the competitive NMDA-R antagonist 3-((R)-2-Carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) at DIV 8. At DIV 8, PFOS also induced glutamate release (9-13 fold increase vs DMSO control) after 1-3 and 24 h exposure, whereas for PFOA a large (80 fold) increase was observed, but only after 24 h. PFOS and PFOA both also increased alanine and decreased serine levels after 24 h exposure. In conclusion, our results indicate that PFOS at concentrations relevant in an occupational setting, may be inducing excitotoxicity, and potentiation of glutamate signalling, via an allosteric action on the NMDA-R or by actions on other elements regulating glutamate release or NMDA-R function. Our results further support our previous findings that PFOS and PFOA at equipotent concentrations induce toxicity via different mechanisms of action.
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Affiliation(s)
- Hanne Friis Berntsen
- Department of Production Animal Clinical Sciences NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102, Oslo, Norway; National Institute of Occupational Health, P.O. Box 8149 Dep N-0033, Oslo, Norway.
| | - Angel Moldes-Anaya
- Research and Development (R&D) Section, PET Imaging Center, University Hospital of North Norway (UNN), Tromsø, Norway; Nuclear Medicine and Radiation Biology Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | - Cesilie Granum Bjørklund
- Department of Production Animal Clinical Sciences NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102, Oslo, Norway
| | - Lorenzo Ragazzi
- Neurobiology Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | | | | | - Steven Verhaegen
- Department of Production Animal Clinical Sciences NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102, Oslo, Norway
| | - Ragnhild Elisabeth Paulsen
- Department of Pharmacy, Section for Pharmacology and Pharmaceutical Biosciences, University of Oslo, Oslo, Norway
| | - Erik Ropstad
- Department of Production Animal Clinical Sciences NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102, Oslo, Norway
| | - R Andrew Tasker
- Department of Biomedical Sciences, University of Prince Edward Island, Charlottetown, PEI, Canada; Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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5
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Berntsen HF, Bjørklund CG, Strandabø R, Haug TM, Moldes-Anaya A, Fuentes-Lazaro J, Verhaegen S, Paulsen RE, Tasker RA, Ropstad E. PFOS-induced excitotoxicity is dependent on Ca2+ influx via NMDA receptors in rat cerebellar granule neurons. Toxicol Appl Pharmacol 2018; 357:19-32. [DOI: 10.1016/j.taap.2018.08.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/10/2018] [Accepted: 08/20/2018] [Indexed: 12/31/2022]
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6
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Wang R, Shi M, Brewer B, Yang L, Zhang Y, Webb DJ, Li D, Xu YQ. Ultrasensitive Graphene Optoelectronic Probes for Recording Electrical Activities of Individual Synapses. NANO LETTERS 2018; 18:5702-5708. [PMID: 30063361 PMCID: PMC6519721 DOI: 10.1021/acs.nanolett.8b02298] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The complex neuronal circuitry connected by submicron synapses in our brain calls for technologies that can map neural networks with ultrahigh spatiotemporal resolution to decipher the underlying mechanisms for multiple aspects of neuroscience. Here we show that, through combining graphene transistor arrays with scanning photocurrent microscopy, we can detect the electrical activities of individual synapses of primary hippocampal neurons. Through measuring the local conductance change of graphene optoelectronic probes directly underneath neuronal processes, we are able to estimate millivolt extracellular potential variations of individual synapses during depolarization. The ultrafast nature of graphene photocurrent response allows for decoding of activity patterns of individual synapses with a sub-millisecond temporal resolution. This new neurotechnology provides promising potentials for recording of electrophysiological outcomes of individual synapses in neural networks.
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Affiliation(s)
- Rui Wang
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37212, USA
| | - Mingjian Shi
- Department of Biological Science and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37212, USA
| | - Bryson Brewer
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37212, USA
| | - Lijie Yang
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37212, USA
| | - Yuchen Zhang
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37212, USA
| | - Donna J. Webb
- Department of Biological Science and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37212, USA
- Department of Cancer Biology, Vanderbilt University, Nashville, TN 37212, USA
| | - Deyu Li
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37212, USA
- Correspondence to: and
| | - Ya-Qiong Xu
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37212, USA
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37212, USA
- Correspondence to: and
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7
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Morland C, Pettersen MN, Hassel B. Hyperosmolar sodium chloride is toxic to cultured neurons and causes reduction of glucose metabolism and ATP levels, an increase in glutamate uptake, and a reduction in cytosolic calcium. Neurotoxicology 2016; 54:34-43. [PMID: 26994581 DOI: 10.1016/j.neuro.2016.03.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 02/01/2023]
Abstract
Elevation of serum sodium, hypernatremia, which may occur during dehydration or treatment with sodium chloride, may cause brain dysfunction and damage, but toxic mechanisms are poorly understood. We found that exposure to excess NaCl, 10-100mmol/L, for 20h caused cell death in cultured cerebellar granule cells (neurons). Toxicity was due to Na(+), since substituting excess Na(+) with choline reduced cell death to control levels, whereas gluconate instead of excess Cl(-) did not. Prior to cell death from hyperosmolar NaCl, glucose consumption and lactate formation were reduced, and intracellular aspartate levels were elevated, consistent with reduced glycolysis or glucose uptake. Concomitantly, the level of ATP became reduced. Pyruvate, 10mmol/L, reduced NaCl-induced cell death. The extracellular levels of glutamate, taurine, and GABA were concentration-dependently reduced by excess NaCl; high-affinity glutamate uptake increased. High extracellular [Na(+)] caused reduction in intracellular free [Ca(2+)], but a similar effect was seen with mannitol, which was not neurotoxic. We suggest that inhibition of glucose metabolism with ensuing loss of ATP is a neurotoxic mechanism of hyperosmolar sodium, whereas increased uptake of extracellular neuroactive amino acids and reduced intracellular [Ca(2+)] may, if they occur in vivo, contribute to the cerebral dysfunction and delirium described in hypernatremia.
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Affiliation(s)
- Cecilie Morland
- Norwegian Defence Research Establishment, Kjeller, Norway; Oslo and Akershus University College of Applied Sciences, Oslo, Norway
| | | | - Bjørnar Hassel
- Norwegian Defence Research Establishment, Kjeller, Norway; Department of Complex Neurology and Neurohabilitation, Oslo University Hospital and The University of Oslo, Oslo, Norway.
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8
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Leng T, Liu A, Wang Y, Chen X, Zhou S, Li Q, Zhu W, Zhou Y, Su X, Huang Y, Yin W, Qiu P, Hu H, Xiong ZG, Zhang J, Yan G. Naturally occurring marine steroid 24-methylenecholestane-3β,5α,6β,19-tetraol functions as a novel neuroprotectant. Steroids 2016; 105:96-105. [PMID: 26631550 DOI: 10.1016/j.steroids.2015.11.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 11/02/2015] [Accepted: 11/19/2015] [Indexed: 12/13/2022]
Abstract
Steroids have been shown to have multiple effects on the nervous system including neuroprotective activities, and they have the potential to be used for the treatment of neurodegenerative diseases. In this current study, we tested the hypothesis that the marine steroid 24-methylenecholestane-3β,5α,6β,19-tetraol (Tetrol) has a neuroprotective effect. (1) We synthesized Tetrol through a multiple step reaction starting from hyodeoxycholic acid (HDCA). (2) We then evaluated the neuroprotective effect of Tetrol with a glutamate-induced neuronal injury model in vitro. Tetrol concentration dependently increased the survival rate of cerebellar granule neurons challenged with toxic concentration of glutamate. Consistently, Tetrol significantly decreased glutamate-induced lactate dehydrogenase (LDH) release with a threshold concentration of 2.5 μM. (3) We further evaluated the neuroprotective effect of Tetrol in a middle cerebral artery occlusion (MCAO)-induced cerebral ischemia model in rat. Tetrol, at a dose of 12 mg/kg, significantly decreased MCAO-induced infarction volume by ∼50%. (4) Finally, we probed the mechanism and found that Tetrol concentration dependently attenuated N-methyl-d-aspartate (NMDA)-induced intracellular calcium ([Ca(2+)]i) increase with an IC50 of 7.8±0.62 μM, and inhibited NMDA currents in cortical neurons with an IC50 of 10.28±0.71 μM. Taken together, we have synthesized and characterized Tetrol as a novel neuroprotectant through negative modulation of NMDA receptors.
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Affiliation(s)
- Tiandong Leng
- Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou, GD 510080, China; Neuroscience Institute, Morehouse School of Medicine, 720 Westview Dr SW, Atlanta, GA 30329, USA
| | - Ailing Liu
- Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou, GD 510080, China
| | - Youqiong Wang
- Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou, GD 510080, China
| | - Xinying Chen
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, GD 510006, China
| | - Shujia Zhou
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, GD 510006, China
| | - Qun Li
- Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou, GD 510080, China
| | - Wenbo Zhu
- Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou, GD 510080, China
| | - Yuehan Zhou
- Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou, GD 510080, China
| | - Xingwen Su
- Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou, GD 510080, China
| | - Yijun Huang
- Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou, GD 510080, China
| | - Wei Yin
- Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou, GD 510080, China
| | - Pengxin Qiu
- Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou, GD 510080, China
| | - Haiyan Hu
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, GD 510006, China
| | - Zhi-gang Xiong
- Neuroscience Institute, Morehouse School of Medicine, 720 Westview Dr SW, Atlanta, GA 30329, USA
| | - Jingxia Zhang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, GD 510006, China.
| | - Guangmei Yan
- Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou, GD 510080, China.
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Microglia in Glia-Neuron Co-cultures Exhibit Robust Phagocytic Activity Without Concomitant Inflammation or Cytotoxicity. Cell Mol Neurobiol 2015; 35:961-75. [PMID: 25894384 DOI: 10.1007/s10571-015-0191-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/28/2015] [Indexed: 12/19/2022]
Abstract
A simple method to co-culture granule neurons and glia from a single brain region is described, and microglia activation profiles are assessed in response to naturally occurring neuronal apoptosis, excitotoxin-induced neuronal death, and lipopolysaccharide (LPS) addition. Using neonatal rat cerebellar cortex as a tissue source, glial proliferation is regulated by omission or addition of the mitotic inhibitor cytosine arabinoside (AraC). After 7-8 days in vitro, microglia in AraC(-) cultures are abundant and activated based on their amoeboid morphology, expressions of ED1 and Iba1, and ability to phagocytose polystyrene beads and the majority of neurons undergoing spontaneous apoptosis. Microglia and phagocytic activities are sparse in AraC(+) cultures. Following exposure to excitotoxic kainate concentrations, microglia in AraC(-) cultures phagocytose most dead neurons within 24 h without exacerbating neuronal loss or mounting a strong or sustained inflammatory response. LPS addition induces a robust inflammatory response, based on microglial expressions of TNF-α, COX-2 and iNOS proteins, and mRNAs, whereas these markers are essentially undetectable in control cultures. Thus, the functional effector state of microglia is primed for phagocytosis but not inflammation or cytotoxicity even after kainate exposure that triggers death in the majority of neurons. This model should prove useful in studying the progressive activation states of microglia and factors that promote their conversion to inflammatory and cytotoxic phenotypes.
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10
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A low-density culture method of cerebellar granule neurons with paracrine support applicable for the study of neuronal morphogenesis. Brain Res 2013; 1539:15-23. [DOI: 10.1016/j.brainres.2013.09.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 09/10/2013] [Accepted: 09/28/2013] [Indexed: 10/26/2022]
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11
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del Olmo-Aguado S, Núñez-Álvarez C, Ji D, Manso AG, Osborne NN. RTP801 immunoreactivity in retinal ganglion cells and its down-regulation in cultured cells protect them from light and cobalt chloride. Brain Res Bull 2013; 98:132-44. [PMID: 23978538 DOI: 10.1016/j.brainresbull.2013.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 08/13/2013] [Accepted: 08/14/2013] [Indexed: 10/26/2022]
Abstract
RTP801, a stress-related protein, is activated by adverse environmental conditions and inhibits the activity of mammalian target of rapamycin (mTOR) in promoting oxidative stress-dependent cell death. RTP801 exists both in the mammalian retina and the lens of the eye. Here, we observed RTP801 immunoreactivity in some retinal ganglion cells. Intravitreal injection of cobalt chloride (CoCl2) to mimick hypoxia influenced retinal GFAP (glial fibrillary acidic protein) and heme oxygenase-1 (HO-1) levels, but did not affect RTP801 immunoreactivity or mRNA content relative to GAPDH. However, RTP801 mRNA was elevated when compared with Brn3a mRNA, suggesting that RTP801 is activated in stressed Brn3a retinal ganglion cells. In cultures of RGC-5 cells, RTP801 immunoreactivity was located in the cytoplasm and partly present in the mitochondria. An insult of blue light or CoCl2 increased RTP801 expression, which was accompanied by cell death. However, in cultures where RTP801 mRNA was down-regulated, the negative influence of blue light and CoCl2 was blunted. Rapamycin nullified the CoCl2-induced up-regulation of RTP801 and attenuated cell death. Moreover, rapamycin was non-toxic to RGC-5 cells, even at a high concentration (10μM). The protective effect of rapamycin on RGC-5 cells caused by the inhibition of RTP801 suggests that rapamycin might attenuate retinal ganglion cell death in situ, as in glaucoma.
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Affiliation(s)
- Susana del Olmo-Aguado
- Fundación de Investigación Oftalmológica, Avda. Doctores Fernández-Vega 34, E-33012 Oviedo, Asturias, Spain
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12
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Effects of Cymbopogon citratus and Ferula assa-foetida extracts on glutamate-induced neurotoxicity. In Vitro Cell Dev Biol Anim 2013; 49:706-15. [DOI: 10.1007/s11626-013-9656-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 06/24/2013] [Indexed: 12/27/2022]
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13
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Oberdoerster J. Isolation of cerebellar granule cells from neonatal rats. ACTA ACUST UNITED AC 2013; Chapter 12:Unit12.7. [PMID: 23045036 DOI: 10.1002/0471140856.tx1207s09] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Cerebellar Granule Cells in Neurotoxicology (Jan Oberdoerster, Aventis Corporation, Research Triangle Park, North Carolina). Cultured neurons allow the researcher to investigate mechanisms of toxicity on a relatively uniform population of cells. Primary cultures of cerebellar granule cells are post-mitotic neurons that are readily isolated and may be used for experimental procedures including electrophysiology, neuronal maturation, and various biochemical and molecular analyses.
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14
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Osborne NN, Ji D, Majid ASA, Del Soldata P, Sparatore A. Glutamate oxidative injury to RGC-5 cells in culture is necrostatin sensitive and blunted by a hydrogen sulfide (H2S)-releasing derivative of aspirin (ACS14). Neurochem Int 2012; 60:365-78. [PMID: 22306773 DOI: 10.1016/j.neuint.2012.01.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 01/03/2012] [Accepted: 01/09/2012] [Indexed: 01/04/2023]
Abstract
Oxidative stress to RGC-5 cells in culture was delivered by exposure to a combination of glutamate (Glu) and buthionine-S,R-sulfoximine (BSO). The effect of the insult on cell survival was quantified by the resazurin-reduction and a dead/live assays. Moreover, breakdown of DNA, the localisation of phosphatidylserine and reactive radical species (ROS) and its quantification were determined. In addition, various proteins and mRNAs were studied using Western blot, real time PCR and immunocytochemistry. ACS14, its sulfurated moiety ACS1 and aspirin were tested for their ability to blunt the negative effects of Glu/BSO on RGC-5 cells. In addition assays were carried out to see whether any of these substances influenced glutathione (GSH). Glu/BSO dose-dependently kills RGC-5 cells by a mechanism that involves an elevation of ROS accompanied by a breakdown of DNA, expression of phosphatidylserine and the activation of p38 MAPK. The process is unaffected by the pan caspase inhibitor z-VAD-fmk, does not involve the activation of apoptosis inducing factor (AIF) but is sensitive to active necrostatin-1. In cell viability studies (resazurin-reduction assay), ACS1 and ACS14 equally counteracted the negative effects of 5mM Glu/BSO to RGC-5 cells but aspirin was only effective with a milder oxidative stress (1 mM Glu/BSO). In all other assays ACS14 was very much more effective than aspirin at counteracting the influence of 5mM Glu/BSO. Moreover, ACS14 and ACS1 directly stimulated GSH while aspirin was ineffective. In addition the neuroprotecive effect of ACS14 was specifically blunted by the non-specific potassium channel blocker glibenclamide. Also the up-regulation of Bcl-2, HO-1 and XIAP induced by 5mM Glu/BSO were all attenuated to a greater extent by ACS14 (20 μM) than aspirin (20 μM). These data show that ACS14 is a very effective neuroprotectant when compared with aspirin. ACS14 maintains its aspirin characteristics and has the ability to release H(2)S. The combined multiple actions of aspirin and H(2)S in the form of ACS14 is worthy to consider for possible use in the treatment of glaucoma.
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Affiliation(s)
- Neville N Osborne
- Nuffield Laboratory of Ophthalmology, University of Oxford, John Radcliffe Hospital, Oxford, UK.
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15
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Gruol DL, Puro A, Hao C, Blakely P, Janneke E, Vo K. Neuroadaptive changes in cerebellar neurons induced by chronic exposure to IL-6. J Neuroimmunol 2011; 239:28-36. [PMID: 21890220 DOI: 10.1016/j.jneuroim.2011.08.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 07/25/2011] [Accepted: 08/10/2011] [Indexed: 01/13/2023]
Abstract
IL-6 is an important signaling molecule in the CNS. CNS neurons express IL-6 receptors and their signal transduction molecules, consistent with a role for IL-6 in neuronal physiology. Research indicates that IL-6 levels are low in the normal brain but can be significantly elevated in CNS injury and disease. Relatively little is known about how the elevated levels of IL-6 affect neurons. In the current study we show that under conditions of chronic exposure, IL-6 induces alterations in the level of protein expression in developing CNS cells. Such changes may play a role in the altered CNS function observed in CNS conditions associated with elevated levels of IL-6 in the CNS.
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Affiliation(s)
- D L Gruol
- Molecular and Integrative Neuroscience Department, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
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16
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Lai B, Pu H, Cao Q, Jing H, Liu X. Activation of caspase-3 and c-Jun NH2-terminal kinase signaling pathways involving heroin-induced neuronal apoptosis. Neurosci Lett 2011; 502:209-13. [PMID: 21856377 DOI: 10.1016/j.neulet.2011.07.046] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/12/2011] [Accepted: 07/26/2011] [Indexed: 01/27/2023]
Abstract
Heroin has been shown to cause spongiform leukoencephalopathy (SLE) in heroin addicts. In this study, we found that heroin could induce apoptosis of primary cultured cerebellar granule cells (CGC) and c-Jun N-terminal kinase (JNK) pathway is activated during CGCs apoptosis. Inhibiting JNK with a specific inhibitor, SP600125, reduced the levels of c-Jun phosphorylation and caspase-3 activation. We also showed that use the JNK inhibitor SP600125, caspase inhibitor z-VAD, or use SP600125 and z-VAD together significantly suppressed cell death induced by heroin. These results indicate that JNK pathway is an important mediator of the neurotoxic effects of heroin and inhibiting JNK activity may represent a new and effective strategy to treat heroin-induced SLE.
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Affiliation(s)
- Bingquan Lai
- Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
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17
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Ramanathan G, Atchison WD. Ca2+ entry pathways in mouse spinal motor neurons in culture following in vitro exposure to methylmercury. Neurotoxicology 2011; 32:742-50. [PMID: 21839771 DOI: 10.1016/j.neuro.2011.07.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 06/06/2011] [Accepted: 07/13/2011] [Indexed: 12/29/2022]
Abstract
Methylmercury (MeHg) is a widespread environmental toxicant with major actions on the central nervous system. Among the neurons reportedly affected in cases of Hg poisoning are motor neurons; however, the direct cellular effects of MeHg on motor neurons have not been reported. Ratiometric fluorescence imaging, using the Ca(2+)-sensitive fluorophore fura-2, was used to examine the effect of MeHg on Ca(2+) homeostasis in primary cultures of mouse spinal motor neurons. In vitro MeHg exposure at concentrations (0.1-2 μM) known to affect other neurons in culture differentially, induced a biphasic rise in fura-2 fluorescence ratio indicating an increase in [Ca(2+)](i). The time-to-onset of these fura-2 fluorescence ratio changes was inversely correlated with MeHg concentration. TPEN (20 μM), a non-Ca(2+), divalent cation chelator, reduced the amplitude of the increase in fura-2 fluorescence induced by MeHg in the first phase, indicating that both Ca(2+) and non-Ca(2+) divalent cations contribute to the MeHg-induced effect. When examining various Ca(2+) entry pathways as possible targets contributing to Ca(2+) influx, we found that excitatory amino acid receptor blockers MK-801 (15 μM), and AP-5 (100 μM)-both NMDA receptor-operated ion channel blockers, CNQX (20 μM), a non-NMDA receptor blocker, and the voltage-dependent Ca(2+) channel blockers nifedipine (1 μM) and ω-conotoxin-GVIA (1 μM) all significantly delayed the development of increased Ca(2+) caused by MeHg. The voltage-dependent Na(+) channel blocker tetrodotoxin (TTX, 1 μM) did not alter the MeHg-induced increases in fura-2 fluorescence ratio. Thus, MeHg alters Ca(2+) homeostasis in mouse spinal motor neurons through excitatory amino acid receptor-mediated pathways, and nifedipine and ω-conotoxin-GVIA-sensitive pathways. Spinal motor neurons are highly sensitive to this effect of acute exposure to MeHg.
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Affiliation(s)
- Gunasekaran Ramanathan
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
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18
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Ginsberg SD. Alterations in discrete glutamate receptor subunits in adult mouse dentate gyrus granule cells following perforant path transection. Anal Bioanal Chem 2010; 397:3349-58. [PMID: 20577723 DOI: 10.1007/s00216-010-3826-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 04/27/2010] [Accepted: 05/04/2010] [Indexed: 01/25/2023]
Abstract
Custom-designed microarray analysis was utilized to evaluate expression levels of glutamate receptors (GluRs) and GluR-interacting protein genes within isolated dentate gyrus granule cells following axotomy of the principal input, the perforant path (PP). Dentate gyrus granule cells were evaluated by microdissection via laser capture microdissection, terminal continuation RNA amplification, and microarray analysis following unilateral PP transections at seven time points. Expression profiles garnered from granule cells on the side ipsilateral to PP transections were compared and contrasted with naive subjects and mice subjected to unilateral occipital cortex lesions. Selected microarray observations were validated by real-time quantitative PCR analysis. Postlesion time-dependent alterations in specific alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors, kainate receptors, N-methyl-D-aspartate (NMDA) receptors, and GluR-interacting protein genes were found across the time course of the study, suggesting a neuroplasticity response associated with the transsynaptic granule cell alterations following axotomy of incoming PP terminals.
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Affiliation(s)
- Stephen D Ginsberg
- Department of Psychiatry, Center for Dementia Research, Nathan Kline Institute, New York University Langone Medical Center, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA.
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19
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The biocompatibility of materials used in printed circuit board technologies with respect to primary neuronal and K562 cells. Biomaterials 2010; 31:1045-54. [DOI: 10.1016/j.biomaterials.2009.10.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 10/09/2009] [Indexed: 01/09/2023]
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20
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Smith AJ, Tauskela JS, Stone TW, Smith RA. Preconditioning with 4-aminopyridine protects cerebellar granule neurons against excitotoxicity. Brain Res 2009; 1294:165-75. [DOI: 10.1016/j.brainres.2009.07.061] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 07/16/2009] [Accepted: 07/18/2009] [Indexed: 01/23/2023]
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21
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Al-Gonaiah M, Smith RA, Stone TW. Xanthine oxidase-induced neuronal death via the oxidation of NADH: prevention by micromolar EDTA. Brain Res 2009; 1280:33-42. [PMID: 19450565 DOI: 10.1016/j.brainres.2009.05.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Revised: 05/07/2009] [Accepted: 05/08/2009] [Indexed: 11/29/2022]
Abstract
The oxidation of xanthine by xanthine oxidase (XO) or xanthine dehydrogenase represents an important source of reactive oxygen species (ROS), which contribute to the damaging consequences of cerebral ischemia, inflammation, and neurodegenerative disorders. However, both enzymes are also able to act on reduced nicotinamide adenine dinucleotide (NADH). The FAD binding site to which NADH binds is distinct from that of the xanthine binding site. We report that the combination of xanthine oxidase and NADH is toxic to cultures of cerebellar granule neurons. Protection by superoxide dismutase (Cu,Zn-SOD or Mn-SOD) or catalase indicates mediation of the toxicity by superoxide and hydrogen peroxide. In addition, pre-incubating XO with EDTA at concentrations as low as 2 microM, prevented the toxicity, indicating that a metal contaminating XO is involved in producing the toxic effects of XO/NADH. It is possible that such a metal might play a role in the toxicity of XO in vivo.
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Affiliation(s)
- Majed Al-Gonaiah
- Neuroscience and Molecular Pharmacology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK
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22
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Preconditioning with NMDA protects against toxicity of 3-nitropropionic acid or glutamate in cultured cerebellar granule neurons. Neurosci Lett 2008; 440:294-8. [PMID: 18565656 DOI: 10.1016/j.neulet.2008.05.066] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Revised: 05/09/2008] [Accepted: 05/20/2008] [Indexed: 12/29/2022]
Abstract
A brief sub-lethal ischaemic stimulus has been reported to protect against subsequent ischaemic damage in vivo, and in vitro following periods of hypoxia or oxygen-glucose deprivation (OGD). Preconditioning against neurotoxic stimuli has been linked to N-methyl-d-aspartate (NMDA) receptors, since receptor blockade prevents the protection afforded by OGD, and low doses of NMDA treatment are capable of preconditioning. The current study demonstrated that NMDA preconditioning also protects against 3-nitropropionic acid (3-NPA), a generator of both excitotoxic and oxidative damage, in addition to glutamate. Cerebellar granule neuronal (CGN) cultures prepared from 8-day neonatal Sprague-Dawley rats were maintained for 8 days prior to NMDA stimulation for 6h. At 9 days in vitro (DIV), preconditioned and control cultures were subjected to a toxic insult (1 microM-10 mM glutamate or 1 microM-10 mM 3-NPA). Neuronal viability was assessed by use of a fluorescein diacetate assay. Protection was effective with 100 microM NMDA preconditioning for 6 h against 1-100 microM glutamate, and also against 1-500 microM 3-NPA. The study demonstrates that NMDA preconditioning can be beneficial against excitotoxic treatments, even when these are potentially complicated by associated oxidative damage and metabolic compromise, as is the case for 3-NPA.
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23
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Strauss KI. Antiinflammatory and neuroprotective actions of COX2 inhibitors in the injured brain. Brain Behav Immun 2008; 22:285-98. [PMID: 17996418 PMCID: PMC2855502 DOI: 10.1016/j.bbi.2007.09.011] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 09/14/2007] [Accepted: 09/20/2007] [Indexed: 12/22/2022] Open
Abstract
Overexpression of COX2 appears to be both a marker and an effector of neural damage after a variety of acquired brain injuries, and in natural or pathological aging of the brain. COX2 inhibitors may be neuroprotective in the brain by reducing prostanoid and free radical synthesis, or by directing arachidonic acid down alternate metabolic pathways. The arachidonic acid shunting hypothesis proposes that COX2 inhibitors' neuroprotective effects may be mediated by increased formation of potentially beneficial eicosanoids. Under conditions where COX2 activity is inhibited, arachidonic acid accumulates or is converted to eicosanoids via lipoxygenases and cytochrome P450 (CYP) epoxygenases. Several P450 eicosanoids have been demonstrated to have beneficial effects in the brain and/or periphery. We suspect that arachidonic acid shunting may be as important to functional recovery after brain injuries as altered prostanoid formation per se. Thus, COX2 inhibition and arachidonic acid shunting have therapeutic implications beyond the suppression of prostaglandin synthesis and free radical formation.
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Affiliation(s)
- Kenneth I. Strauss
- Mayfield Neurotrauma Research Lab, Department of Neurosurgery, University of Cincinnati College of Medicine, 231 Albert Sabin Way, ML515, Cincinnati, OH 45267 ()
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24
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Taylor DL, Jones F, Kubota ESFCS, Pocock JM. Stimulation of microglial metabotropic glutamate receptor mGlu2 triggers tumor necrosis factor alpha-induced neurotoxicity in concert with microglial-derived Fas ligand. J Neurosci 2006; 25:2952-64. [PMID: 15772355 PMCID: PMC6725132 DOI: 10.1523/jneurosci.4456-04.2005] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Activated microglia may be detrimental to neuronal survival in a number of neurodegenerative diseases. Thus, strategies that reduce microglial neurotoxicity may have therapeutic benefit. Stimulation of group II metabotropic glutamate (mGlu) receptors on rat primary microglia with the specific group II agonist 2S,2'R,3'R-2-(2',3'-dicarboxy-cyclopropyl)glycine for 24 h induced microglial activation and resulted in a neurotoxic microglial phenotype. These effects were attributable to preferential mGlu2 stimulation, because N-acetyl-L-aspartyl-L-glutamate, a specific mGlu3 agonist, did not induce microglial activation or neurotoxicity. Stimulation of microglial mGlu2 but not mGlu3 induced caspase-3 activation in cerebellar granule neurons in culture, using microglial-conditioned media as well as cocultures. Stimulation of microglial mGlu2 induced tumor necrosis factor-alpha (TNFalpha) release, which contributed to microglial neurotoxicity mediated via neuronal TNF receptor 1 and caspase-3 activation. Stimulation of microglial group I or III mGlu receptors did not induce TNFalpha release. TNFalpha was only neurotoxic in the presence of microglia or microglial-conditioned medium. The toxicity of TNFalpha could be prevented by coexposure of neurons to conditioned medium from microglia stimulated by the specific group III agonist L-2-amino-4-phosphono-butyric acid. The neurotoxicity of TNFalpha derived from mGlu2-stimulated microglia was potentiated by microglial-derived Fas ligand (FasL), the death receptor ligand. FasL was constitutively expressed in microglia and shed after mGlu2 stimulation. Our data suggest that selective and inverse modulation of microglial mGlu2 and mGlu3 may prove a therapeutic target in neuroinflammatory diseases such as Alzheimer's disease and multiple sclerosis.
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MESH Headings
- Animals
- Animals, Newborn
- Apoptosis/drug effects
- Blotting, Western
- Caspase 3
- Caspases/metabolism
- Cell Count/methods
- Cells, Cultured
- Cerebellum/cytology
- Coculture Techniques/methods
- Culture Media, Conditioned/pharmacology
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Drug Interactions
- Ectodysplasins
- Excitatory Amino Acid Antagonists/pharmacology
- Fas Ligand Protein
- Gene Expression/drug effects
- Lipopolysaccharides/pharmacology
- Membrane Glycoproteins/toxicity
- Membrane Proteins/metabolism
- Mice
- Microglia/drug effects
- Microglia/metabolism
- Mitochondria/drug effects
- Neurons/drug effects
- Neurons/metabolism
- Neurotoxicity Syndromes/etiology
- Neurotoxicity Syndromes/metabolism
- Neurotoxicity Syndromes/physiopathology
- Nitric Oxide Synthase Type II/metabolism
- Rats
- Rats, Wistar
- Receptors, Metabotropic Glutamate/metabolism
- Receptors, Tumor Necrosis Factor, Type I/metabolism
- Receptors, Tumor Necrosis Factor, Type II/metabolism
- Time Factors
- Tumor Necrosis Factor-alpha/metabolism
- Tumor Necrosis Factor-alpha/toxicity
- Tumor Necrosis Factors/metabolism
- Tumor Necrosis Factors/toxicity
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Affiliation(s)
- Deanna L Taylor
- Cell Signalling Laboratory, Department of Neuroinflammation, Institute of Neurology, University College London, London WC1N 1PJ, United Kingdom
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25
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Pérez-Capote K, Serratosa J, Solà C. Excitotoxic and apoptotic neuronal death induce different patterns of glial activation in vitro. J Neurochem 2005; 94:226-37. [PMID: 15953365 DOI: 10.1111/j.1471-4159.2005.03183.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We have studied glial activation in rat cerebellar neuronal-glial cultures after inducing neuronal death using various stimuli. Cultures were exposed to 100 microm glutamate for 20 min, which induces excitotoxic neuronal death, or to potassium/serum deprivation, which induces apoptosis of granule neurons. We evaluated alterations in several parameters related to glial activation: nuclear factor-kappaB activation, nitric oxide and tumour necrosis factor-alpha production, which are associated with a pro-inflammatory response, glial proliferation and phagocytic activity. Although the two experimental models of neuronal damage resulted in the death of most neuronal cells within 24 h, differences were observed in the response of the various glial parameters evaluated. While nitric oxide production was not detected in any case, tumour necrosis factor-alpha production, nuclear factor-kappaB activation and glial proliferation were only induced in the presence of excitotoxic neuronal death. However, phagocytosis was induced in both cases, although earlier in the case of apoptotic neuronal death. These results show that glial cells respond to excitotoxic neuronal death with an inflammatory response associated with proliferation and phagocytosis. In contrast, whilst glial cells do not produce pro-inflammatory molecules in the presence of apoptotic neuronal death, phagocytic activity is rapidly induced.
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Affiliation(s)
- Kamil Pérez-Capote
- Department of Pharmacology and Toxicology, Institut d'Investigacions Biomèdiques de Barcelona-Consejo Superior de investigaciones Cientificas (CSIC), Institut d'Investigaciones Biomediques Augusb Pi i Sunyer (IDIBAPS), Spain
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26
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Monaco EA, Vallano ML. Roscovitine triggers excitotoxicity in cultured granule neurons by enhancing glutamate release. Mol Pharmacol 2005; 68:1331-42. [PMID: 16051748 DOI: 10.1124/mol.105.012732] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cerebellar granule neurons are highly susceptible to injury in vivo and in vitro, and primary cultures are widely used to characterize relevant receptors and signaling pathways. However, there are problems associated with their use. In particular, cultures are typically grown in medium supplemented with elevated KCl levels because it improves survival, but accumulating evidence indicates that this causes profound neuroadaptations. For example, growth in elevated KCl levels renders neurons electrically silent. Thus, they cannot be used to examine excitotoxicity of synaptic origins. On the other hand, cultures grown in physiological medium are rarely studied because a proportion undergoes apoptosis. Herein, we provide evidence that mature neurons cultured in physiological KCl develop spontaneous action potentials that support survival through N-methyl-D-aspartate (NMDA) receptor-mediated mechanisms. Furthermore, the cdk inhibitor roscovitine enhances the coupling between tetrodotoxin-sensitive action potentials and P/Q-type voltage-dependent calcium channels (VDCCs), thereby converting this survival program to excitotoxicity of synaptic origin. Therefore, roscovitine-triggered necrosis requires spontaneous Na+-based action potentials (tetrodotoxin inhibits, (+/-)-2-amino-4-phosphonobutyric acid enhances), P/Q-type VDCC currents (omega-agatoxin-IVA and omega-conotoxin-MVIIC inhibit, but not omega-conotoxin-GVIA), intact vesicle fusion processes (tetanus toxin inhibits), and transmitter-filled vesicles (concanamycin and bafilomycin inhibit). From a postsynaptic standpoint, roscovitine-mediated excitotoxicity requires the functionally linked activation of alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionate/kainate (AMPA/KA) and NMDA receptors, which is consistent with evidence that activated AMPA/KA receptors relieve the voltage-dependent Mg2+ block of NMDA receptors, resulting in excitotoxic Ca2+ influx. In the end, NMDA receptor-linked pathways transduce excitotoxicity. On the other hand, L-type VDCC blockers are not protective. Further characterization of this new model is expected to provide important insights about excitotoxicity of synaptic origins and about roscovitine as a selective modulator of this process.
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Affiliation(s)
- Edward A Monaco
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, 750 East Adams St, Syracuse, NY 13210, USA
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27
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Ogita K, Okuda H, Watanabe M, Nagashima R, Sugiyama C, Yoneda Y. In vivo treatment with the K+ channel blocker 4-aminopyridine protects against kainate-induced neuronal cell death through activation of NMDA receptors in murine hippocampus. Neuropharmacology 2005; 48:810-21. [PMID: 15829253 DOI: 10.1016/j.neuropharm.2004.12.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Revised: 12/04/2004] [Accepted: 12/21/2004] [Indexed: 11/21/2022]
Abstract
Activation of NMDA receptors has been shown to induce either neuronal cell death or neuroprotection against excitotoxicity in cultured neurons in vitro. To elucidate in vivo neuroprotective role of NMDA receptors, we investigated the effects of activation of NMDA receptors by endogenous glutamate on kainate-induced neuronal damage to the mouse hippocampus in vivo. The systemic administration of the K+ channel blocker 4-aminopyridine (4-AP, 5 mg/kg, i.p.) induced expression of c-Fos in the hippocampal neuronal cell layer, which expression was completely abolished by the noncompetitive NMDA receptor antagonist MK-801, thus indicating that the administration of 4-AP would activate NMDA receptors in the hippocampal neurons. The prior administration of 4-AP at 1 h to 1 day before significantly prevented kainate-induced pyramidal cell death in the hippocampus and expression of pyramidal cells immunoreactive with an antibody against single-stranded DNA. Further immunohistochemical study on deoxyribonuclease II revealed that the pretreatment with 4-AP led to complete abolition of deoxyribonuclease II expression induced by kainate in the CA1 and CA3 pyramidal cells. The neuroprotection mediated by 4-AP was blocked by MK-801 and by the adenosine A1 antagonist 8-cyclopenthyltheophylline. Taken together, in vivo activation of NMDA receptors is capable of protecting against kainate-induced neuronal damage through blockade of DNA fragmentation induced by deoxyribonuclease II in the murine hippocampus.
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Affiliation(s)
- Kiyokazu Ogita
- Department of Pharmacology, Setsunan University Faculty of Pharmaceutical Sciences, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan.
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28
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Miao B, Yin XH, Pei DS, Zhang QG, Zhang GY. Neuroprotective effects of preconditioning ischemia on ischemic brain injury through down-regulating activation of JNK1/2 via N-methyl-D-aspartate receptor-mediated Akt1 activation. J Biol Chem 2005; 280:21693-9. [PMID: 15797868 DOI: 10.1074/jbc.m500003200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Our previous studies have demonstrated that the JNK signaling pathway plays an important role in ischemic brain injury and is mediated via glutamate receptor 6. Others studies have shown that N-methyl-d-aspartate (NMDA) receptor is involved in the neuroprotection of ischemic preconditioning. Here we examined whether ischemic preconditioning down-regulates activation of the mixed lineage kinase-JNK signaling pathway via NMDA receptor-mediated Akt1 activation. In our present results, ischemic preconditioning could not only inhibit activations of mixed lineage kinase 3, JNK1/2, and c-Jun but also enhanced activation of Akt1. In addition, both NMDA (an agonist of NMDA receptor) and preconditioning showed neuroprotective effects. In contrast, ketamine, an antagonist of NMDA receptor, prevented the above effects of preconditioning. Further studies indicated that LY294002, an inhibitor of phosphoinositide 3-kinase that is an upstream signaling protein of Akt1, could block neuroprotection of preconditioning, and KN62, an inhibitor of calmodulin-dependent protein kinase, also achieved the same effects as LY294002. Therefore, both phosphoinositide 3-kinase and calmodulin-dependent protein kinase are involved in the activation of Akt1 in ischemic tolerance. Taken together, our results indicate that preconditioning can inhibit activation of JNK signaling pathway via NMDA receptor-mediated Akt1 activation and induce neuroprotection in hippocampal CA1 region.
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Affiliation(s)
- Bei Miao
- Research Center for Biochemistry and Molecular Biology, Xuzhou Medical College, 84 West Huai-hai Road, Xuzhou, Jiangsu 221002, China
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29
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Pi R, Li W, Lee NTK, Chan HHN, Pu Y, Chan LN, Sucher NJ, Chang DC, Li M, Han Y. Minocycline prevents glutamate-induced apoptosis of cerebellar granule neurons by differential regulation of p38 and Akt pathways. J Neurochem 2005; 91:1219-30. [PMID: 15569265 DOI: 10.1111/j.1471-4159.2004.02796.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Minocycline has been shown to have remarkably neuroprotective qualities, but underlying mechanisms remain elusive. We reported here the robust neuroprotection by minocycline against glutamate-induced apoptosis through regulations of p38 and Akt pathways. Pre-treatment of cerebellar granule neurons (CGNs) with minocycline (10-100 microm) elicited a dose-dependent reduction of glutamate excitotoxicity and blocked glutamate-induced nuclear condensation and DNA fragmentations. Using patch-clamping and fluorescence Ca2+ imaging techniques, it was found that minocycline neither blocked NMDA receptors, nor reduced glutamate-caused rises in intracellular Ca2+. Instead, confirmed by immunoblots, minocycline in vivo and in vitro was shown to directly inhibit the activation of p38 caused by glutamate. A p38-specific inhibitor, SB203580, also attenuated glutamate excitotoxicity. Furthermore, the neuroprotective effects of minocycline were blocked by phosphatidylinositol 3-kinase (PI3-K) inhibitors LY294002 and wortmannin, while pharmacologic inhibition of glycogen synthase kinase 3beta (GSK3beta) attenuated glutamate-induced apoptosis. In addition, immunoblots revealed that minocycline reversed the suppression of phosphorylated Akt and GSK3beta caused by glutamate, as were abolished by PI3-K inhibitors. These results demonstrate that minocycline prevents glutamate-induced apoptosis in CGNs by directly inhibiting p38 activity and maintaining the activation of PI3-K/Akt pathway, which offers a novel modality as to how the drug exerts protective effects.
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Affiliation(s)
- Rongbiao Pi
- Department of Biochemistry, Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
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Atlante A, Giannattasio S, Bobba A, Gagliardi S, Petragallo V, Calissano P, Marra E, Passarella S. An increase in the ATP levels occurs in cerebellar granule cells en route to apoptosis in which ATP derives from both oxidative phosphorylation and anaerobic glycolysis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1708:50-62. [PMID: 15949983 DOI: 10.1016/j.bbabio.2005.01.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Revised: 12/13/2004] [Accepted: 01/21/2005] [Indexed: 11/28/2022]
Abstract
Although it is recognized that ATP plays a part in apoptosis, whether and how its level changes en route to apoptosis as well as how ATP is synthesized has not been fully investigated. We have addressed these questions using cultured cerebellar granule cells. In particular, we measured the content of ATP, ADP, AMP, IMP, inosine, adenosine and L-lactate in cells undergoing apoptosis during the commitment phase (0-8 h) in the absence or presence of oligomycin or/and of citrate, which can inhibit totally the mitochondrial oxidative phosphorylation and largely the substrate-level phosphorylation in glycolysis, respectively. In the absence of inhibitors, apoptosis was accompanied by an increase in ATP and a decrease in ADP with 1:1 stoichiometry, with maximum ATP level found at 3 h apoptosis, but with no change in levels of AMP and its breakdown products and with a relatively low level of L-lactate production. Consistently, there was an increase in the cell energy charge and in the ratio ([ATP][AMP])/[ADP](2). When the oxidative phosphorylation was completely blocked by oligomycin, a decrease of the ATP content was found both in control cells and in cells undergoing apoptosis, but nonetheless cells still died by apoptosis, as shown by checking DNA laddering and by death prevention due to actinomycin D. In this case, ATP was provided by anaerobic glycolysis, as suggested by the large increase of L-lactate production. On the other hand, citrate itself caused a small decrease in ATP level together with a huge decrease in L-lactate production, but it had no effect on cell survival. When ATP level was further decreased due to the presence of both oligomycin and citrate, death occurred via necrosis at 8 h, as shown by the lack of DNA laddering and by death prevention found due to the NMDA receptor antagonist MK801. However, at a longer time, when ATP level was further decreased, cells died neither via apoptosis nor via glutamate-dependent necrosis, in a manner similar to something like to energy catastrophe. Our results shows that cellular ATP content increases in cerebellar granule cell apoptosis, that the role of oxidative phosphorylation is facultative, i.e. ATP can also derive from anaerobic glycolysis, and that the type of cell death depends on the ATP availability.
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Affiliation(s)
- Anna Atlante
- Istituto di Biomembrane e Bioenergetica, CNR, Via G. Amendola, 165/A-70126 Bari, Italy.
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31
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Lisi A, Ciotti MT, Ledda M, Pieri M, Zona C, Mercanti D, Rieti S, Giuliani L, Grimaldi S. Exposure to 50 Hz electromagnetic radiation promote early maturation and differentiation in newborn rat cerebellar granule neurons. J Cell Physiol 2005; 204:532-8. [PMID: 15754325 DOI: 10.1002/jcp.20322] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The wish of this work is the study of the effect of electromagnetic (EMF) radiations at a frequency of 50 Hz on the development of cerebellar granule neurons (CGN). Granule neurons, prepared from newborn rat cerebellum (8 days after birth), were cultured after plate-seeding in the presence of EMF radiations, with the plan of characterizing their cellular and molecular biochemistry, after exposure to the electromagnetic stimulus. Five days challenge to EMF radiations showed, by the cytotoxic glutamate (Glu) pulse test, a 30% decrease of cells survival, while only 5% of mortality was reported for unexposed sample. Moreover, blocking the glutamate receptor (GluR) with the Glu competitor MK-801, no toxicity effect after CGN challenge to EMF radiations and Glu was detected. By patch-clamp recording technique, the Kainate-induced currents from 6 days old exposed CGN exhibited a significant increase with respect to control cells. Western blot and reverse transcription-polymerase chain reaction (RT-PCR) analyses show that EMF exposure of rats CGN, induces a change in both GluRs proteins and mRNAs expression with respect to control. In addition, the use of monoclonal antibody raised against neurofilament protein (NF-200) reveals an increase in NF-200 synthesis in the exposed CGN. All these results indicate that exposure to non-ionizing radiations contribute to a premature expression of GluRs reducing the life span of CGN, leading to a more rapid cell maturation.
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Affiliation(s)
- A Lisi
- Institute of Neurobiology and Molecular Medicine, CNR, Rome, Italy
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32
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Behbahani H, Rickle A, Concha H, Ankarcrona M, Winblad B, Cowburn RF. Flow cytometry as a method for studying effects of stressors on primary rat neurons. J Neurosci Res 2005; 82:432-41. [PMID: 16184608 DOI: 10.1002/jnr.20634] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The mechanisms associated with cell death have been an important focus for neurobiology research. In the present study, the methodology of flow cytometry was used to optimize quantification of the toxic effects of tumor necrosis factor-alpha (TNF-alpha), trans-4-hydroxy-2-nonenal (4-HNE), and aged amyloid-beta (Abeta1-42) on rat primary cortical neurons. The fluorescent dyes annexin V-FITC and propidium iodide (PI) were used to identify populations of viable, early apoptotic, necrotic and late apoptotic cells by flow cytometry. Prior to exposure, the primary cultures showed 83% cell viability. Flow cytometry following labeling of cells with a specific neuronal marker, TUJ-1, revealed 82% pure neuronal populations, whereas approximately 7% were astrocytic as shown by glial fibrillary acidic protein positivity. Exposure of primary cultures to TNF-alpha, 4-HNE, and aged Abeta1-42 gave an increased number of early apoptotic cells. We show that flow cytometry is a suitable method for quantifying effects of different stressors on neurons in primary cultures. This technique could be useful for screening and testing of pharmacological compounds relevant to neurodegenerative disorders.
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Affiliation(s)
- H Behbahani
- Neurotec Department, Division of Experimental Geriatrics, Novum, KASPAC, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
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Conroy SM, Nguyen V, Quina LA, Blakely-Gonzales P, Ur C, Netzeband JG, Prieto AL, Gruol DL. Interleukin-6 produces neuronal loss in developing cerebellar granule neuron cultures. J Neuroimmunol 2004; 155:43-54. [PMID: 15342195 DOI: 10.1016/j.jneuroim.2004.06.014] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Revised: 05/19/2004] [Accepted: 06/02/2004] [Indexed: 11/18/2022]
Abstract
CNS levels of the cytokine interleukin-6 (IL-6) are elevated during CNS injury and disease, but it is unclear if IL-6 contributes to the pathologic process. Our studies show that in a well-characterized CNS developmental model system, primary cultures of rodent cerebellar granule neurons, chronic exposure to IL-6 during neuronal development can result in cell damage and death in a subpopulation of developing granule neurons. Chronic exposure to IL-6 also increased the susceptibility of the granule neurons to a toxic insult produced by excessive activation of NMDA receptors. These results are consistent with a role for IL-6 in the neuropathology observed in the developing CNS during injury and disease.
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Affiliation(s)
- Shannon M Conroy
- Department of Neuropharmacology, The Scripps Research Institute, La Jolla, CA 92037, USA
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34
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Castiglione M, Spinsanti P, Iacovelli L, Lenti L, Martini F, Gradini R, Di Giorgi Gerevini V, Caricasole A, Caruso A, De Maria R, Nicoletti F, Melchiorri D. Activation of Fas receptor is required for the increased formation of the disialoganglioside GD3 in cultured cerebellar granule cells committed to apoptotic death. Neuroscience 2004; 126:889-98. [PMID: 15207324 DOI: 10.1016/j.neuroscience.2004.04.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/06/2004] [Indexed: 10/26/2022]
Abstract
Apoptosis was induced in cultured cerebellar granule cells by lowering extracellular K+ concentrations (usually from 25 to 10 mM). The apoptotic phenotype was preceded by an early and transient increase in the intracellular levels of the disialoganglioside, GD3, which behaves as a putative pro-apoptotic factor. We examined whether activation of Fas receptor mediates the increase in GD3 formation in granule cells committed to die. Degenerating granule cells showed increased expression of both Fas receptor and its ligand (Fas-L), at times that coincided with the increase in GD3 levels and the induction of GD3 synthase mRNA. Addition of neutralizing anti-Fas-L antibodies reduced the extent of 'low-K+'-induced apoptosis and abolished the increase in GD3 levels and GD3 synthase mRNA. Similar reductions were observed in cultures prepared from gld or lpr mice, which harbor loss-of-function mutations of Fas-L and Fas receptor, respectively. In addition, exogenous application of soluble Fas-L further enhanced both the increase in GD3 formation and cell death in cultured granule cells switched from 25 into 10 mM K+. We conclude that activation of Fas receptor is entirely responsible for the increase in GD3 levels and contributes to the development of apoptosis by trophic deprivation in cultured cerebellar granule cells.
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Affiliation(s)
- M Castiglione
- Department of Human Physiology and Pharmacology, University of Rome La Sapienza, Piazzale Aldo Moro, 5, 00185, Rome, Italy
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35
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Mangiavacchi S, Wolf ME. Stimulation of N-methyl-d-aspartate receptors, AMPA receptors or metabotropic glutamate receptors leads to rapid internalization of AMPA receptors in cultured nucleus accumbens neurons. Eur J Neurosci 2004; 20:649-57. [PMID: 15255976 DOI: 10.1111/j.1460-9568.2004.03511.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In hippocampus and other regions, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors are inserted into synapses during long-term potentiation and removed during long-term depression. However, little is known about regulation of AMPA receptor trafficking in the nucleus accumbens (NAc), despite growing evidence that glutamate-dependent forms of plasticity in the NAc contribute to drug addiction. Using postnatal rat NAc cultures and an immunocytochemical method that selectively detects newly internalized GluR1, we studied the regulation of AMPA receptor internalization in NAc neurons by glutamate agonists. Newly internalized GluR1 was detected during 15 or 30 min of incubation at room temperature, indicating a basal rate of GluR1 turnover. The rate of GluR1 internalization was increased by glutamate (50 microM) within 5 min of its addition. Glutamate-induced GluR1 internalization was partially blocked by either an AMPA receptor antagonist (CNQX; 20 microM) or an N-methyl-D-aspartate (NMDA) receptor antagonist (APV; 50 microM). Both NMDA (50 microM) and AMPA (50 microM) increased GluR1 internalization in a Ca(2+)-dependent manner. The NMDA effect was blocked by APV while the AMPA effect was blocked by APV or CNQX. We interpret these findings to suggest that NMDA and AMPA ultimately trigger GluR1 internalization through the same NMDA receptor-dependent pathway. The effect of glutamate was also partially blocked by the group 1 metabotropic glutamate receptor antagonist N-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxamide (PHCCC; 50 microM), while the group 1 agonist 3,5-dihydroxyphenylglycine (DHPG; 50 microM) stimulated GluR1 internalization. These data suggest that AMPA receptors on NAc neurons may be subject to rapid regulation of their surface expression in response to changes in the activity of glutamate inputs from cortical and limbic regions.
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Affiliation(s)
- Simona Mangiavacchi
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science/The Chicago Medical School, 3333 Green Bay Road, North Chicago, IL 60064-3095, USA
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Tajima H, Sunaga K, Tanaka M, Kuwae T, Katsube N. Overexpression of Glyceraldehyde-3-phospahe Dehydrogenase Is Not Involved in 5-Hydroxytryptamine (5-HT)-Induced Necrosis in Cultured Cerebrocortical Neurons. Biol Pharm Bull 2004; 27:1224-7. [PMID: 15305026 DOI: 10.1248/bpb.27.1224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cerebrocortical cell cultures were prepared from 1-d-old rats. On post-culture day 6, 5-hydroxytryptamine (5-HT) was added to the medium and cells were exposed for another 3 d. 5-HT elicited cytotoxicity in a dose-dependent manner, and the survival rate of neuronal cells was decreased to 64.9+/-5.0% at 0.1 mM concentration. Chromatin staining with Hoechst 33258 and electron microscopy revealed that the 5-HT-induced neuronal death was entirely due to necrosis. Pretreatments with glyceraldehyde-3-phosphate dehydrogenase (GAPDH) antisense oligonucleotide and several classical apoptotic inhibitors did not exhibit neuroprotection in this paradigm. Northern blot analysis showed that the enhancement of GAPDH mRNA levels was undetected during cell death. The present results demonstrate that GAPDH overexpression is not involved in the 5-HT-induced necrotic death pathway.
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Affiliation(s)
- Hisao Tajima
- Discovery Research Laboratories I, Minase Institute, Ono Pharmaceutical Co., Ltd, Osaka, Japan
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37
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Abe K, Abe Y, Saito H. Agmatine induces glutamate release and cell death in cultured rat cerebellar granule neurons. Brain Res 2003; 990:165-71. [PMID: 14568341 DOI: 10.1016/s0006-8993(03)03454-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigated the effect of agmatine on cell viability of rat cerebellar granule neurons in a high-K+ (27.5 mM) medium. Exposure of cultured rat cerebellar granule neurons to agmatine (200-800 microM) resulted in a significant decrease in cell viability. Agmatine-induced neuronal death began to occur 6-12 h after addition, and gradually progressed. The agmatine neurotoxicity was attenuated by N-methyl-D-aspartate (NMDA) receptor antagonists and by enzymatic degradation of L-glutamate with glutamic pyruvic transaminase. Furthermore, a significant increase in extracellular L-glutamate concentration was detected before cell death occurred. In addition, agmatine-induced glutamate release and cell death were both blocked by pretreatment with botulinum toxin C, which is known to specifically inhibit the exocytosis. The agmatine neurotoxicity was not observed when extracellular K+ concentration was lower (10 mM). These results suggest that agmatine induces glutamate release through the exocytosis and thereby causes NMDA receptor-mediated neuronal death in conditions in which extracellular K+ concentrations are elevated.
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Affiliation(s)
- Kazuho Abe
- Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
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38
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Ogita K, Okuda H, Yamamoto Y, Nishiyama N, Yoneda Y. In vivo neuroprotective role of NMDA receptors against kainate-induced excitotoxicity in murine hippocampal pyramidal neurons. J Neurochem 2003; 85:1336-46. [PMID: 12753091 DOI: 10.1046/j.1471-4159.2003.01778.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Activation of NMDA receptors has been shown to induce either neuronal cell death or neuroprotection against excitotoxicity in cultured cerebellar granule neurons in vitro. We have investigated the effects of pretreatment with NMDA on kainate-induced neuronal cell death in mouse hippocampus in vivo. The systemic administration of kainate (30 mg/kg), but not NMDA (100 mg/kg), induced severe damage in pyramidal neurons of the hippocampal CA1 and CA3 subfields 3-7 days later, without affecting granule neurons in the dentate gyrus. An immunohistochemical study using an anti-single-stranded DNA antibody and TdT-mediated dUTP nick end labeling analysis both revealed that kainate, but not NMDA, induced DNA fragmentation in the CA1 and CA3 pyramidal neurons 1-3 days after administration. Kainate-induced neuronal loss was completely prevented by the systemic administration of NMDA (100 mg/kg) 1 h to 1 day previously. No pyramidal neuron was seen with fragmented DNA in the hippocampus of animals injected with kainate 1 day after NMDA treatment. The neuroprotection mediated by NMDA was prevented by the non-competitive NMDA receptor antagonist MK-801. Taken together these results indicate that in vivo activation of NMDA receptors is capable of protecting against kainate-induced neuronal damage through blockade of DNA fragmentation in murine hippocampus.
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Affiliation(s)
- Kiyokazu Ogita
- Department of Pharmacology, Setsunan University Faculty of Pharmaceutical Sciences, Hirakata, Osaka, Japan.
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39
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Polazzi E, Contestabile A. Neuron-conditioned media differentially affect the survival of activated or unstimulated microglia: evidence for neuronal control on apoptotic elimination of activated microglia. J Neuropathol Exp Neurol 2003; 62:351-62. [PMID: 12722827 DOI: 10.1093/jnen/62.4.351] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
It is presently unknown what types of neuronal signals maintain microglial cells resting in the normal brain or control their activation in neuropathology. Recent data suggest that microglia activation induces apoptosis and that healthy neurons are controllers of the activation state and immune functions of microglia. In the present study we have evaluated, on microglial cells in cultures, whether neurons are able to affect their survival in resting conditions or upon activation with the bacterial endotoxin, lipopolysaccharide (LPS). We report that neuron-conditioned culture media induced apoptosis of LPS-stimulated, but not of unstimulated, microglia. This effect was, however, only present when conditioned media had been exposed to differentiated neurons and not to immature ones, and was absent when glutamate receptors had been pharmacologically blocked in neuronal cultures. The effect was also blocked by heat-inactivation of the conditioned media. Media conditioned with either differentiated or undifferentiated cerebellar granule neurons positively affected the survival of unstimulated microglial cells when the standard concentration of fetal bovine serum (10%) was included in the culture media. Our results highlight the ability of differentiated neurons to maintain a controlled inflammatory state through production of factor(s) favoring the apoptotic elimination of activated microglia. They also suggest that immature neurons may, on the contrary, favor the survival of microglia during development.
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Takano H, Fukushi H, Morishima Y, Shirasaki Y. Calmodulin and calmodulin-dependent kinase II mediate neuronal cell death induced by depolarization. Brain Res 2003; 962:41-7. [PMID: 12543454 DOI: 10.1016/s0006-8993(02)03932-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Depolarization has been known to play an important role in the neuronal damage that occurs following cerebral ischemia. In the present study, we investigated the roles of calmodulin (CaM) and CaM-dependent enzymes in depolarization-induced neuronal cell death. Treatment of primary cortical neurons with 10 microM veratridine, a voltage sensitive Na(+) channel activator, induced cell death as indicated by lactate dehydrogenase leakage from neurons. CaM antagonists (calmidazolium, trifluoperazine, W-7, and W-5) inhibited cell death induced by veratridine in a concentration-dependent manner. CaM kinase II (CaMKII) inhibitors (KN-62, KN-93, and myristoylated autocamtide-2 related inhibitory peptide), but not inhibitors of nitric oxide synthase or calcineurin, prevented veratridine-induced neuronal cell death. Veratridine rapidly activated CaMKII in neurons, and CaM antagonists and a CaMKII inhibitor suppressed the CaMKII activation. These results suggest that the CaM-CaMKII pathway contributes to depolarization-evoked cell death in neurons.
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Affiliation(s)
- Hiromichi Takano
- New Product Research Laboratories II, Daiichi Pharmaceutical Co., Ltd., 1-16-13 Kitakasai, Edogawa-ku, Tokyo 134-8630, Japan
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41
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Foran PG, Mohammed N, Lisk GO, Nagwaney S, Lawrence GW, Johnson E, Smith L, Aoki KR, Dolly JO. Evaluation of the therapeutic usefulness of botulinum neurotoxin B, C1, E, and F compared with the long lasting type A. Basis for distinct durations of inhibition of exocytosis in central neurons. J Biol Chem 2003; 278:1363-71. [PMID: 12381720 DOI: 10.1074/jbc.m209821200] [Citation(s) in RCA: 230] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Seven types (A-G) of botulinum neurotoxin (BoNT) target peripheral cholinergic neurons where they selectively proteolyze SNAP-25 (BoNT/A, BoNT/C1, and BoNT/E), syntaxin1 (BoNT/C1), and synaptobrevin (BoNT/B, BoNT/D, BoNT/F, and BoNT/G), SNARE proteins responsible for transmitter release, to cause neuromuscular paralysis but of different durations. BoNT/A paralysis lasts longest (4-6 months) in humans, hence its widespread clinical use for the treatment of dystonias. Molecular mechanisms underlying these distinct inhibitory patterns were deciphered in rat cerebellar neurons by quantifying the half-life of the effect of each toxin, the speed of replenishment of their substrates, and the degradation of the cleaved products, experiments not readily feasible at motor nerve endings. Correlation of target cleavage with blockade of transmitter release yielded half-lives of inhibition for BoNT/A, BoNT/C1, BoNT/B, BoNT/F, and BoNT/E (31, 25, approximately 10, approximately 2, and approximately 0.8 days, respectively), equivalent to the neuromuscular paralysis times found in mice, with recovery of release coinciding with reappearance of the intact SNAREs. A limiting factor for the short neuroparalytic durations of BoNT/F and BoNT/E is the replenishment of synaptobrevin or SNAP-25, whereas pulse labeling revealed that extended inhibition by BoNT/A, BoNT/B, or BoNT/C1 results from longevity of each protease. These novel findings could aid development of new toxin therapies for patients resistant to BoNT/A and effective treatments for human botulism.
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Affiliation(s)
- Patrick G Foran
- Centre for Neurobiochemistry, Department of Biological Sciences, Imperial College, London SW7 2AZ, United Kingdom
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42
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Pelidou SH, Schultzberg M, Iverfeldt K. Increased sensitivity to N-methyl-D-aspartate receptor-induced excitotoxicity in cerebellar granule cells from interleukin-1 receptor type I-deficient mice. J Neuroimmunol 2002; 133:108-15. [PMID: 12446013 DOI: 10.1016/s0165-5728(02)00369-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The effects of chronic exposure to excitatory amino acids (EAAs) were examined in cultured cerebellar granule cells (CGCs) from wild type (WT) and interleukin-1 receptor type I (IL-1RI)-deficient mice. After 8 days in culture, the cells were exposed to 100 microM glutamate or 300 microM N-methyl-D-aspartate (NMDA) for 24 h. Analysis of cell viability, as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay and phase-contrast microscopy revealed that CGCs from IL-1RI-deficient mice were more vulnerable to EAAs as compared to the WT controls. The results indicate that IL-1RI signalling is important for neuronal survival. The effect of glutamate on the CGCs from IL-1RI-deficient mice was decreased by the non-competitive NMDA-receptor antagonist MK-801, supporting the involvement of NMDA receptors in the glutamate-induced excitotoxicity.
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Affiliation(s)
- Sigliti Henrietta Pelidou
- Department of Neurochemistry and Neurotoxicology, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91, Stockholm, Sweden
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43
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Mercanti D, Galli C, Liguori M, Ciotti MT, Gullà P, Calissano P. Identification of the Serum Complex Which Induces Cerebellar Granule Cell In Vitro Differentiation and Resistance to Excitatory Amino Acids. Eur J Neurosci 2002; 4:733-744. [PMID: 12106317 DOI: 10.1111/j.1460-9568.1992.tb00182.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The protein complex promoting in vitro terminal differentiation of cerebellar granule cells has been isolated from rabbit serum. We designate the complex the neurite outgrowth and adhesion complex (NOAC). The apparent molecular weight, evaluated by gel filtration, is 80 - 100 kDa. Rat cerebellar granule cells cultured in NOAC exhibit much lower glial cell contamination and survive, in their differentiated state, much longer than in 10% foetal calf serum. While they bind tetanus toxin, express specific antigens such as synapsin I, synaptophisin and A2B5, and release [3H]d-aspartate in a fashion similar to that shown by cells cultured in foetal calf serum, they show a 60% reduction in the total number of kainate binding sites. Excitatory amino acid (EAA)-triggered and depolarization-stimulated calcium influx, measured in the presence of different agonists, is 50 - 80% lower in NOAC-cultured cells. NOAC cells are resistant to excitotoxic stimuli carried by EAAs or by depolarizing treatments with 50 mM KCl or 6 microM veratridine. The marked resistance of NOAC-cultured neurons to EAAs can be attributed to decreased calcium entry through EAA-coupled and voltage-gated calcium channels and possibly to other, as yet unidentified, phenotypic properties of these cells. These findings demonstrate that rabbit serum contains one or more polypeptide(s) endowed with the properties of promoting in vitro survival and differentiation of rat cerebellar granule cells and of conferring an EAA-resistant phenotype.
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Affiliation(s)
- D. Mercanti
- Istituto di Neurobiologia, C.N.R., Viale C. Marx, 15/43, 00137 Rome, Italy
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44
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Hoch W, Betz H, Schramm M, Wolters I, Becker CM. Modulation by NMDA Receptor Antagonists of Glycine Receptor Isoform Expression in Cultured Spinal Cord Neurons. Eur J Neurosci 2002; 4:389-395. [PMID: 12106346 DOI: 10.1111/j.1460-9568.1992.tb00887.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two developmentally regulated isoforms of the inhibitory glycine receptor harbouring different alpha subunit variants, GlyRN (neonatal) and GlyRA (adult), have previously been identified in rodent spinal cord. Primary cultures of embyronic spinal neurons, however, express predominantly GlyRN. Here, N-methyl-d-aspartate (NMDA) receptor antagonists were found to significantly increase glycine receptor levels in mouse spinal cord cultures. In the presence of 2-amino-5-phosphonovalerate or MK-801 (dizocilpine), both GlyRN and GlyRA contents were elevated, as revealed by isoform-selective immunoassays and amplification of corresponding alpha subunit transcripts by the polymerase chain reaction. This effect of NMDA receptor antagonists was restricted to a 'sensitive' period within the second week after plating. Apparently, NMDA receptor-mediated glutamate neurotoxicity prevented GlyRA accumulation under standard culture conditions. Our data indicate that neuronal maturation in cell culture depends on conditions which minimize cell death resulting from glutamate release into the culture medium.
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Affiliation(s)
- W. Hoch
- Zentrum für Molekulare Biologie, Universität Heidelberg, Im Neuenheimer Feld 282, W-6900 Heidelberg, FRG
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Melchiorri D, Martini F, Lococo E, Gradini R, Barletta E, De Maria R, Caricasole A, Nicoletti F, Lenti L. An early increase in the disialoganglioside GD3 contributes to the development of neuronal apoptosis in culture. Cell Death Differ 2002; 9:609-15. [PMID: 12032669 DOI: 10.1038/sj.cdd.4401020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2001] [Revised: 12/05/2001] [Accepted: 01/09/2002] [Indexed: 11/09/2022] Open
Abstract
We induced apoptosis in primary cultures of cerebellar granule neurons by switching the growing medium into a medium containing lower concentrations of K(+) (5 or 10 mM instead of 25 mM) or, alternatively, by addition of staurosporine. The apoptotic phenotype was always preceded by an early increase in the intracellular levels of the disialoganglioside GD3, which peaked at 2-6 h and returned back to normal at 12 h. GD3 synthase, the enzyme that forms GD3 from the monosialoganglioside GM3, was also induced at early times after the induction of apoptosis in granule cells. Immunofluorescent staining showed that GD3 increased in neuronal cell bodies and neurites, but was never localized in cell nuclei. In cultures switched into a low K(+)-containing medium, exogenously applied GD3, but not the disialoganglioside GD1a, accelerated the development of neuronal apoptosis. In contrast, the antisense-induced knock-down of GD3 synthase was protective against granule cell death induced by lowering extracellular K(+) from 25 to 10 - but not 5 - mM. These results demonstrate that an early and transient increase in GD3 synthesis is one of the factors that contribute to the induction of neuronal apoptosis in culture.
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Affiliation(s)
- D Melchiorri
- Department of Human Physiology and Pharmacology, University of Rome La Sapienza, Italy
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Palestini P, Botto L, Guzzi F, Calvi C, Ravasi D, Masserini M, Pitto M. Developmental changes in the protein composition of sphingolipid- and cholesterol-enriched membrane domains of rat cerebellar granule cells. J Neurosci Res 2002; 67:729-38. [PMID: 11891786 DOI: 10.1002/jnr.10170] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The biological role of cell membrane domains has been investigated in a number of eukariotic cells, but less attention has been paid to the neuron. In the present investigation, we assessed the changes in lipid and protein composition of detergent-resistant membrane fractions prepared from cultured rat cerebellar granule cells, during differentiation and maturation in vitro. At any stage of the cell life, low-density, detergent-resistant fractions, characterised by the specific presence of prion protein, were enriched in glycolipids, cholesterol, and sphingomyelin. The enrichment in sphingomyelin was developmentally regulated, increasing continuously during cell differentiation and maturation. Concerning proteins, domains were enriched in Fyn and TAG-1, which present exclusively within this fraction at any stage of cell culture, and in GAP-43, mainly during the differentiation stage. On the other side, proteins affecting signal transduction and cytoskeleton-related proteins (heterotrimeric G-proteins, protein kinase C, MARCKS, tubulin), were not enriched within detergent-resistant fractions during cell differentiation, but were recovered within this fraction in mature neurons. These results indicate that during different cellular life stages, specific proteins are recruited within detergent-resistant membrane domains of the neuron and suggest their involvement in specific physiological phenomena (differentiation, maturation and/or aging).
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Affiliation(s)
- Paola Palestini
- Department of Experimental, Environmental Medicine and Biotechnologies (DIMESAB), University of Milano-Bicocca, Monza, Italy.
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47
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Kovács AD, Cebers G, Cebere A, Liljequist S. Selective and AMPA receptor-dependent astrocyte death following prolonged blockade of glutamate reuptake in rat cerebellar cultures. Exp Neurol 2002; 174:58-71. [PMID: 11869034 DOI: 10.1006/exnr.2001.7839] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this study we examined the effects of prolonged l-trans-pyrrolidine-2,4-dicarboxylate (PDC)-induced glutamate reuptake blockade on the viability of glial cells in cerebellar granule cell cultures. Immunofluorescence staining for the glial-specific intermediate filament protein, GFAP, revealed that the PDC- induced increase of extracellular glutamate concentration was accompanied by increased astrocyte death, while neurons and oligodendrocytes remained intact and viable. Astrocytic cell death was manifested as fragmentation of processes and cell bodies. The selective astrocyte death was completely prevented by the competitive alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/kainate receptor antagonist, NBQX (10 microM), whereas MK-801 (10 microM), a noncompetitive blocker of N-methyl-D-aspartate receptors, gave only partial protection. Double staining for GFAP and the AMPA receptor subunits GluR2/3 showed that astrocytes had much higher immunoreactivity for GluR2/3 than neurons or oligodendrocytes, suggesting that the number of AMPA receptors is likely to be higher on astrocytes. Furthermore, we employed real-time RT-PCR to measure GluR1-4 subunit mRNA expression in control and PDC-exposed cultures. Following treatment with PDC, GluR1 and GluR4 mRNAs were reduced by 40% and GluR3 was reduced by 70% relative to control levels. In contrast, GluR2 expression was not affected by the PDC treatment, indicating that GluR3 was the dominant type of AMPA receptor subunit expressed on astrocytes. Our results show that astrocytes appear to be more vulnerable than neurons or oligodendrocytes to a gradual increase in the extracellular glutamate concentration, suggesting that astrocytes may be critically involved in the pathophysiology of slowly developing chronic neurodegenerative disorders.
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Affiliation(s)
- Attila D Kovács
- Department of Clinical Neuroscience, Karolinska Institutet, SE-17176 Stockholm, Sweden
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Daniels M, Brown DR. High extracellular potassium protects against the toxicity of cytosine arabinoside but is not required for the survival of cerebellar granule cells in vitro. Mol Cell Neurosci 2002; 19:281-91. [PMID: 11860280 DOI: 10.1006/mcne.2001.1070] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Depolarization of cerebellar granule cells with elevated potassium has been described as essential to maintain their survival in culture. There are several reports that this is only specific for rat cerebellar granule cells and not those of mouse. We reinvestigated this issue and found that although high potassium enhanced the survival of cerebellar granule cells from both rat and mouse it was not essential for the survival of those cultures. Further analysis of the culture system indicated that high potassium offered protection against the toxicity of glutamate and cytosine arabinose (Ara C), a standard antimitotic additive to cultures of granule cells. Ara C was found to be toxic to cerebellar cells after potassium withdrawal at concentrations standardly used in culturing these cells (10 microM). High potassium was found to diminish the expression of p53. Ara C toxicity is known to utilize the p53-dependent signaling pathway to initiate apoptosis. Another depolarizing agent, veratridine, offers no protection against Ara C but we provide evidence that the protective effect of high potassium against Ara C is mediated through calcium balance within the cells. We suggest that there is no requirement for high potassium in terms of cerebellar granule cell survival. The previously proposed role for high potassium in the survival cerebellar granule cells is rather a protective effect against toxic substances in serum such as glutamate or against agents such as Ara C.
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Affiliation(s)
- Maki Daniels
- Department of Biochemistry, Cambridge University, Cambridge, United Kingdom
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Meshorer E, Erb C, Gazit R, Pavlovsky L, Kaufer D, Friedman A, Glick D, Ben-Arie N, Soreq H. Alternative splicing and neuritic mRNA translocation under long-term neuronal hypersensitivity. Science 2002; 295:508-12. [PMID: 11799248 DOI: 10.1126/science.1066752] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
To explore neuronal mechanisms underlying long-term consequences of stress, we studied stress-induced changes in the neuritic translocation of acetylcholinesterase (AChE) splice variants. Under normal conditions, we found the synaptic AChE-S mRNA and protein in neurites. Corticosterone, anticholinesterases, and forced swim, each facilitated a rapid (minutes), yet long-lasting (weeks), shift from AChE-S to the normally rare AChE-R mRNA, promoted AChE-R mRNA translocation into neurites, and induced enzyme secretion. Weeks after stress, electrophysiological measurements in hippocampus slices displayed apparently normal evoked synaptic responses but extreme hypersensitivity to both anticholinesterases and atropine. Our findings suggest that neuronal hypersensitivity under stress involves neuritic replacement of AChE-S with AChE-R.
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Affiliation(s)
- Eran Meshorer
- Department of Biological Chemistry, The Institute of Life Sciences and The Eric Roland Center for Neurodegenerative Diseases, The Hebrew University of Jerusalem, Israel 91904
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Ginsberg SD, Martin LJ. Axonal transection in adult rat brain induces transsynaptic apoptosis and persistent atrophy of target neurons. J Neurotrauma 2002; 19:99-109. [PMID: 11852982 DOI: 10.1089/089771502753460277] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We used the fimbria-fornix (FF) transection model of axonal injury to test the hypothesis that transneuronal degeneration occurs in the adult central nervous system in response to deafferentation. The medial mammillary nucleus, pars medialis (MMNm) was analyzed by light and electron microscopy at 3, 7, 14, and 30 days, and 6 months after unilateral FF transection in adult rat to identify the time course of neuronal responses in a remote target. Presynaptic terminals and neuronal cell bodies degenerated in the MMNm ipsilateral to FF transection. Terminal degeneration occurred predominantly at 3 and 7 days postlesion. Between 14 and 30 days postlesion, neuronal number in the MMNm decreased (approximately 20%). Two forms of neuronal degeneration were found in the MMNm after deafferentation. Some neurons died apoptotically. Other neurons underwent vacuolar degeneration. In these latter neurons, somatodendritic pathology occurred at 14 and 30 days and 6 months postlesion. The ultrastructure of this vacuolar degeneration was characterized by disorganization of the cytoplasm, formation of membrane-bound vacuolar cisternae and membranous inclusions, loss of organelles, cytoplasmic pallor, and chromatin alterations. This study shows that both anterograde axonal degeneration and transneuronal degeneration occur in a fornical target after FF axon transection. This transneuronal degeneration can be classified as sustained neuronal atrophy or transsynaptic apoptosis.
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Affiliation(s)
- Stephen D Ginsberg
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA
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