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Krzyczmonik A, Grafinger KE, Keller T, Pfeifer L, Forsback S, Haaparanta-Solin M, Gouverneur V, López-Picón F, Solin O. Evaluation of [ 18F]FMTEB in Sprague Dawley rats as a PET tracer for metabotropic glutamate receptor 5. Nucl Med Biol 2023; 116-117:108309. [PMID: 36521341 DOI: 10.1016/j.nucmedbio.2022.108309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 10/31/2022] [Accepted: 11/17/2022] [Indexed: 11/27/2022]
Abstract
INTRODUCTION [18F]FMTEB, along with other tracers, was developed as a promising PET radioligand for imaging metabotropic glutamate receptor subtype 5 (mGluR5). Despite favorable preliminary results, it has not been used further for studies of mGluR5. This paper presents an in-depth preclinical evaluation of [18F]FMTEB in healthy Sprague Dawley rats. METHODS [18F]FMTEB was synthesized from a boronic ester precursor using copper-mediated fluorination. In vivo PET imaging was performed on six rats, of which three were pre-treated with a high affinity mGluR5 receptor antagonist. An additional 18 rats were used for ex vivo experiments for metabolite analyses in plasma, brain and urine, and for biodistribution and ex vivo brain autoradiography at different time points. RESULTS [18F]FMTEB was synthesized in adequate radiochemical yield and a molar activity of 154 ± 64 GBq/μmol. Both in vivo imaging and ex vivo brain autoradiography showed high specificity for mGluR5, and the blocking experiments showed a clear decrease in radioactivity in mGluR5-rich brain areas. Metabolite analyses confirmed fast metabolism of the tracer in plasma. The percentage of parent compound in brain tissue exceeded 90 % up to 90 min after injection. CONCLUSION [18F]FMTEB produced via copper-mediated 18F-fluorination fulfilled the requirements for preclinical evaluation in rats. The absence of specific uptake in cerebellum and absence of defluorination of the tracer allowed cerebellum to be used as a reference tissue. Due to the fast kinetics in rats, the region-to-cerebellum ratios equilibrated within 30 min. These results prove [18F]FMTEB to be a good candidate for mapping mGluR5 in rat brain and a suitable alternative to [18F]FPEB.
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Affiliation(s)
- Anna Krzyczmonik
- Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland
| | - Katharina E Grafinger
- Turku PET Centre, Preclinical Imaging, University of Turku, Turku, Finland; MediCity Research Laboratory, University of Turku, Turku, Finland
| | - Thomas Keller
- Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland
| | - Lukas Pfeifer
- University of Oxford, Chemistry Research Laboratory, Oxford, United Kingdom
| | - Sarita Forsback
- Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland; Department of Chemistry, University of Turku, Turku, Finland
| | - Merja Haaparanta-Solin
- Turku PET Centre, Preclinical Imaging, University of Turku, Turku, Finland; MediCity Research Laboratory, University of Turku, Turku, Finland
| | | | - Francisco López-Picón
- Turku PET Centre, Preclinical Imaging, University of Turku, Turku, Finland; MediCity Research Laboratory, University of Turku, Turku, Finland
| | - Olof Solin
- Turku PET Centre, Radiopharmaceutical Chemistry Laboratory, University of Turku, Turku, Finland; Department of Chemistry, University of Turku, Turku, Finland; Turku PET Centre, Accelerator Laboratory, Åbo Akademi University, Turku, Finland.
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Role of amyloid beta (25-35) neurotoxicity in the ferroptosis and necroptosis as modalities of regulated cell death in Alzheimer's disease. Neurotoxicology 2023; 94:71-86. [PMID: 36347329 DOI: 10.1016/j.neuro.2022.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/26/2022] [Accepted: 11/03/2022] [Indexed: 11/06/2022]
Abstract
Neuronal cell death as a prominent pathological feature contributes to cognitive decline and memory loss in Alzheimer's disease. We investigated the role of two forms of cell death pathways, ferroptosis and necroptosis, and their interactions following entorhinal cortex (EC) amyloidopathy. The Aβ25-35 was bilaterally injected into the rat's EC, and Morris Water Maze was applied to determine spatial performance one week after Aβ injection. For evaluation of ferroptosis and necroptosis involvement in Aβ induced pathology, ferroptosis inhibitor, Ferrostatin (Fer-1), and necroptosis inhibitor, Necrostatin (Nec-1), were injected into the EC during training days of behavioral test. Our behavioral and histological assessment showed spatial learning and memory impairment, along with neuropathology changes such as cell survival and intracellular Aβ deposits in response to EC amyloidopathy, which were ameliorated by treatment with Fer-1 or Nec-1. The expression of ferroptosis key factors GPX4 and SLC7A11 were decreased and the level of TfR was increased following Aβ toxicity. Also, Necroptosis pathway related factors RIP1, RIP3, and MLKL were modulated by Aβ neurotoxicity. However, application of Fer-1 or Nec-1 could inhibit the hippocampal ferroptosis and necroptosis pathways due to EC amyloidopathy. Our data also demonstrated that Aβ-induced necroptosis suppressed by Fer-1, although Nec-1 had no effect on ferroptosis, indicating that ferroptosis pathway is upstream of necroptosis process in the Aβ neurotoxicity. Moreover, Aβ induced hippocampal mGLUR5 overexpression and reduced level of STIM1/2 recovered by Fer-1 or Nec-1. According to our findings ferroptosis and necroptosis pathways are involved in Aβ neurotoxicity through modulation of mGLUR5 and STIM1/2 signaling.
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Yamasaki T, Okada M, Hiraishi A, Mori W, Zhang Y, Fujinaga M, Wakizaka H, Kurihara Y, Nengaki N, Zhang MR. Upregulation of Striatal Metabotropic Glutamate Receptor Subtype 1 (mGluR1) in Rats with Excessive Glutamate Release Induced by N-Acetylcysteine. Neurotox Res 2022; 40:26-35. [PMID: 34981453 DOI: 10.1007/s12640-021-00449-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 10/15/2021] [Accepted: 11/16/2021] [Indexed: 10/19/2022]
Abstract
The aim of this study is to investigate the changes in expression of metabotropic glutamate (Glu) receptor subtype 1 (mGluR1), a key molecule involved in neuroexcitetoxicity, during excessive Glu release in the brain by PET imaging. An animal model of excessive Glu release in the brain was produced by intraperitoneally implanting an Alzet osmotic pump containing N-acetylcysteine (NAC), an activator of the cysteine/Glu antiporter, into the abdomen of rats. Basal Glu concentration in the brain was measured by microdialysis, which showed that basal Glu concentration in NAC-treated rats (0.31 µM) was higher than that in saline-treated rats (0.17 µM) at day 7 after the implantation of the osmotic pump. Similarly, PET studies with [11C]ITDM, a useful radioligand for mGluR1 imaging exhibited that the striatal binding potential (BPND) of [11C]ITDM for mGluR1 in PET assessments was increased in NAC-treated animals at day 7 after implantation (2.30) compared with before implantation (1.92). The dynamic changes in striatal BPND during the experimental period were highly correlated with basal Glu concentration. In conclusion, density of mGluR1 is rapidly upregulated by increases in basal Glu concentration, suggesting that mGluR1 might to be a potential biomarker of abnormal conditions in the brain.
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Affiliation(s)
- Tomoteru Yamasaki
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
| | - Maki Okada
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Atsuto Hiraishi
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Wakana Mori
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Yiding Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Masayuki Fujinaga
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Hidekatsu Wakizaka
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Yusuke Kurihara
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.,SHI Accelerator Service Co. Ltd, 1-17-6 Osaki, Shinagawa-ku, Tokyo, 141-0032, Japan
| | - Nobuki Nengaki
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.,SHI Accelerator Service Co. Ltd, 1-17-6 Osaki, Shinagawa-ku, Tokyo, 141-0032, Japan
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
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Su LD, Wang N, Han J, Shen Y. Group 1 Metabotropic Glutamate Receptors in Neurological and Psychiatric Diseases: Mechanisms and Prospective. Neuroscientist 2021; 28:453-468. [PMID: 34088252 PMCID: PMC9449437 DOI: 10.1177/10738584211021018] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) are G-protein coupled receptors
that are activated by glutamate in the central nervous system (CNS).
Basically, mGluRs contribute to fine-tuning of synaptic efficacy and
control the accuracy and sharpness of neurotransmission. Among eight
subtypes, mGluR1 and mGluR5 belong to group 1 (Gp1) family, and are
implicated in multiple CNS disorders, such as Alzheimer’s disease,
autism, Parkinson’s disease, and so on. In the present review, we
systematically discussed underlying mechanisms and prospective of Gp1
mGluRs in a group of neurological and psychiatric diseases, including
Alzheimer’s disease, Parkinson’s disease, autism spectrum disorder,
epilepsy, Huntington’s disease, intellectual disability, Down’s
syndrome, Rett syndrome, attention-deficit hyperactivity disorder,
addiction, anxiety, nociception, schizophrenia, and depression, in
order to provide more insights into the therapeutic potential of Gp1
mGluRs.
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Affiliation(s)
- Li-Da Su
- Neuroscience Care Unit, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Na Wang
- School of Medicine, Zhejiang University City College, Hangzhou, China
| | - Junhai Han
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, China
| | - Ying Shen
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China
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Chandran R, Kumar M, Kesavan L, Jacob RS, Gunasekaran S, Lakshmi S, Sadasivan C, Omkumar R. Cellular calcium signaling in the aging brain. J Chem Neuroanat 2019; 95:95-114. [DOI: 10.1016/j.jchemneu.2017.11.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/03/2017] [Accepted: 11/07/2017] [Indexed: 12/21/2022]
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Braidy N, Poljak A, Marjo C, Rutlidge H, Rich A, Jugder BE, Jayasena T, Inestrosa NC, Sachdev PS. Identification of Cerebral Metal Ion Imbalance in the Brain of Aging Octodon degus. Front Aging Neurosci 2017; 9:66. [PMID: 28405187 PMCID: PMC5370394 DOI: 10.3389/fnagi.2017.00066] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 03/03/2017] [Indexed: 01/18/2023] Open
Abstract
The accumulation of redox-active transition metals in the brain and metal dyshomeostasis are thought to be associated with the etiology and pathogenesis of several neurodegenerative diseases, and Alzheimer’s disease (AD) in particular. As well, distinct biometal imaging and role of metal uptake transporters are central to understanding AD pathogenesis and aging but remain elusive, due inappropriate detection methods. We therefore hypothesized that Octodon degus develop neuropathological abnormalities in the distribution of redox active biometals, and this effect may be due to alterations in the expression of lysosomal protein, major Fe/Cu transporters, and selected Zn transporters (ZnTs and ZIPs). Herein, we report the distribution profile of biometals in the aged brain of the endemic Chilean rodent O. degus—a natural model to investigate the role of metals on the onset and progression of AD. Using laser ablation inductively coupled plasma mass spectrometry, our quantitative images of biometals (Fe, Ca, Zn, Cu, and Al) appear significantly elevated in the aged O. degus and show an age-dependent rise. The metals Fe, Ca, Zn, and Cu were specifically enriched in the cortex and hippocampus, which are the regions where amyloid plaques, tau phosphorylation and glial alterations are most commonly reported, whilst Al was enriched in the hippocampus alone. Using whole brain extracts, age-related deregulation of metal trafficking pathways was also observed in O. degus. More specifically, we observed impaired lysosomal function, demonstrated by increased cathepsin D protein expression. An age-related reduction in the expression of subunit B2 of V-ATPase, and significant increases in amyloid beta peptide 42 (Aβ42), and the metal transporter ATP13a2 were also observed. Although the protein expression levels of the zinc transporters, ZnT (1,3,4,6, and 7), and ZIP7,8 and ZIP14 increased in the brain of aged O. degus, ZnT10, decreased. Although no significant age-related change was observed for the major iron/copper regulator IRP2, we did find a significant increase in the expression of DMT1, a major transporter of divalent metal species, 5′-aminolevulinate synthase 2 (ALAS2), and the proto-oncogene, FOS. Collectively, our data indicate that transition metals may be enriched with age in the brains of O. degus, and metal dyshomeostasis in specific brain regions is age-related.
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Affiliation(s)
- Nady Braidy
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales Sydney, NSW, Australia
| | - Anne Poljak
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South WalesSydney, NSW, Australia; Mark Wainwright Analytical Centre, University of New South WalesSydney, NSW, Australia; School of Medical Sciences, Faculty of Medicine, University of New South WalesSydney, NSW, Australia
| | - Chris Marjo
- Mark Wainwright Analytical Centre, University of New South Wales Sydney, NSW, Australia
| | - Helen Rutlidge
- Mark Wainwright Analytical Centre, University of New South Wales Sydney, NSW, Australia
| | - Anne Rich
- Mark Wainwright Analytical Centre, University of New South Wales Sydney, NSW, Australia
| | - Bat-Erdene Jugder
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales Sydney, NSW, Australia
| | - Tharusha Jayasena
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales Sydney, NSW, Australia
| | - Nibaldo C Inestrosa
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South WalesSydney, NSW, Australia; Centre for Ageing and Regeneration, Faculty of Biological Sciences, Pontifical Catholic University of ChileSantiago, Chile
| | - Perminder S Sachdev
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South WalesSydney, NSW, Australia; Neuropsychiatric Institute, Euroa Centre, Prince of Wales HospitalSydney, NSW, Australia
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Malhotra A, Younesi E, Bagewadi S, Hofmann-Apitius M. Linking hypothetical knowledge patterns to disease molecular signatures for biomarker discovery in Alzheimer's disease. Genome Med 2014; 6:97. [PMID: 25484918 PMCID: PMC4256903 DOI: 10.1186/s13073-014-0097-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 10/09/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A number of compelling candidate Alzheimer's biomarkers remain buried within the literature. Indeed, there should be a systematic effort towards gathering this information through approaches that mine publicly available data and substantiate supporting evidence through disease modeling methods. In the presented work, we demonstrate that an integrative gray zone mining approach can be used as a way to tackle this challenge successfully. METHODS The methodology presented in this work combines semantic information retrieval and experimental data through context-specific modeling of molecular interactions underlying stages in Alzheimer's disease (AD). Information about putative, highly speculative AD biomarkers was harvested from the literature using a semantic framework and was put into a functional context through disease- and stage-specific models. Staging models of AD were further validated for their functional relevance and novel biomarker candidates were predicted at the mechanistic level. RESULTS Three interaction models were built representing three stages of AD, namely mild, moderate, and severe stages. Integrated analysis of these models using various arrays of evidence gathered from experimental data and published knowledge resources led to identification of four candidate biomarkers in the mild stage. Mode of action of these candidates was further reasoned in the mechanistic context of models by chains of arguments. Accordingly, we propose that some of these 'emerging' potential biomarker candidates have a reasonable mechanistic explanation and deserve to be investigated in more detail. CONCLUSIONS Systematic exploration of derived hypothetical knowledge leads to generation of a coherent overview on emerging knowledge niches. Integrative analysis of this knowledge in the context of disease mechanism is a promising approach towards identification of candidate biomarkers taking into consideration the complex etiology of disease. The added value of this strategy becomes apparent particularly in the area of biomarker discovery for neurodegenerative diseases where predictive biomarkers are desperately needed.
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Affiliation(s)
- Ashutosh Malhotra
- Department of Bioinformatics, Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, 53754 Sankt Augustin, Germany ; Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn-Aachen International Center for Information Technology, 53113 Bonn, Germany
| | - Erfan Younesi
- Department of Bioinformatics, Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, 53754 Sankt Augustin, Germany
| | - Shweta Bagewadi
- Department of Bioinformatics, Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, 53754 Sankt Augustin, Germany ; Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn-Aachen International Center for Information Technology, 53113 Bonn, Germany
| | - Martin Hofmann-Apitius
- Department of Bioinformatics, Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, 53754 Sankt Augustin, Germany ; Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn-Aachen International Center for Information Technology, 53113 Bonn, Germany
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Influence of electroacupuncture on COX activity of hippocampal mitochondria in senescence-accelerated mouse prone 8 mice. JOURNAL OF ACUPUNCTURE AND TUINA SCIENCE 2014. [DOI: 10.1007/s11726-014-0773-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Michetti C, Romano E, Altabella L, Caruso A, Castelluccio P, Bedse G, Gaetani S, Canese R, Laviola G, Scattoni ML. Mapping pathological phenotypes in reelin mutant mice. Front Pediatr 2014; 2:95. [PMID: 25237666 PMCID: PMC4154529 DOI: 10.3389/fped.2014.00095] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 08/21/2014] [Indexed: 11/20/2022] Open
Abstract
Autism Spectrum Disorders (ASD) are neurodevelopmental disorders with multifactorial origin characterized by social communication deficits and the presence of repetitive behaviors/interests. Several studies showed an association between the reelin gene mutation and increased risk of ASD and a reduced reelin expression in some brain regions of ASD subjects, suggesting a role for reelin deficiency in ASD etiology. Reelin is a large extracellular matrix glycoprotein playing important roles during development of the central nervous system. To deeply investigate the role of reelin dysfunction as vulnerability factor in ASD, we assessed the behavioral, neurochemical, and brain morphological features of reeler male mice. We recently reported a genotype-dependent deviation in the ultrasonic vocal repertoire and a general delay in motor development of reeler pups. We now report that adult male heterozygous (Het) reeler mice did not show social behavior and communication deficits during male-female social interactions. Wildtype and Het mice showed a typical light/dark locomotor activity profile, with a peak during the central interval of the dark phase. However, when faced with a mild stressful stimulus (a saline injection) only Het mice showed an over response to stress. In addition to the behavioral studies, we conducted high performance liquid chromatography and magnetic resonance imaging and spectroscopy to investigate whether reelin mutation influences brain monoamine and metabolites levels in regions involved in ASD. Low levels of dopamine in cortex and high levels of glutamate and taurine in hippocampus were detected in Het mice, in line with clinical data collected on ASD children. Altogether, our data detected subtle but relevant neurochemical abnormalities in reeler mice supporting this mutant line, particularly male subjects, as a valid experimental model to estimate the contribution played by reelin deficiency in the global ASD neurobehavioral phenotype.
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Affiliation(s)
- Caterina Michetti
- Neurotoxicology and Neuroendocrinology Section, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità , Rome , Italy ; Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome , Rome , Italy
| | - Emilia Romano
- Behavioural Neuroscience Section, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità , Rome , Italy ; Bambino Gesù Children's Hospital, Istituto Di Ricovero e Cura a Carattere Scientifico , Rome , Italy
| | - Luisa Altabella
- Molecular and Cellular Imaging Section, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità , Rome , Italy
| | - Angela Caruso
- Neurotoxicology and Neuroendocrinology Section, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità , Rome , Italy ; Department of Psychology, School of Behavioural Neuroscience, Sapienza University of Rome , Rome , Italy
| | - Paolo Castelluccio
- Neurotoxicology and Neuroendocrinology Section, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità , Rome , Italy
| | - Gaurav Bedse
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome , Rome , Italy
| | - Silvana Gaetani
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome , Rome , Italy
| | - Rossella Canese
- Molecular and Cellular Imaging Section, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità , Rome , Italy
| | - Giovanni Laviola
- Behavioural Neuroscience Section, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità , Rome , Italy
| | - Maria Luisa Scattoni
- Neurotoxicology and Neuroendocrinology Section, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità , Rome , Italy
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Mori T, Shimizu N, Shibasaki M, Suzuki T. Involvement of the arachidonic acid cascade in the hypersusceptibility to pentylenetetrazole-induced seizure during diazepam withdrawal. Biol Pharm Bull 2013. [PMID: 23207777 DOI: 10.1248/bpb.b12-00542] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study was designed to clarify whether the arachidonic acid cascade contributes to the decreased threshold for pentylenetetrazole-induced seizure under benzodiazepine withdrawal in mice. The seizure threshold for pentylenetetrazole was significantly decreased by the discontinuation of chronic treatment with diazepam. The decrease in the seizure threshold for pentylenetetrazole during diazepam withdrawal was significantly suppressed by intracerebroventricular (i.c.v.) pretreatment with the phospholipase A(2) inhibitor quinacrine (30, 100 nmol) and the lipoxygenase inhibitor nordihydroguaiaretic acid (10, 30 nmol). In contrast, the decreased seizure threshold in the diazepam-withdrawal group was intensified by pretreatment with the cyclooxygenase inhibitor diclofenac (56 nmol). These compounds did not alter the threshold for seizure in a control group. These findings suggest that enhancement of the arachidonic acid cascade may contribute to the hypersusceptibility to pentylenetetrazole-induced seizure during diazepam withdrawal.
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Affiliation(s)
- Tomohisa Mori
- Department of Toxicology, School of Pharmacy, Hoshi University, 2–4–41 Ebara, Shinagawa-ku, Tokyo 142–8501, Japan
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Ménard C, Quirion R. Group 1 metabotropic glutamate receptor function and its regulation of learning and memory in the aging brain. Front Pharmacol 2012; 3:182. [PMID: 23091460 PMCID: PMC3469824 DOI: 10.3389/fphar.2012.00182] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 09/23/2012] [Indexed: 12/22/2022] Open
Abstract
Normal aging is generally characterized by a slow decline of cognitive abilities albeit with marked individual differences. Several animal models have been studied to explore the molecular and cellular mechanisms underlying this phenomenon. The excitatory neurotransmitter glutamate and its receptors have been closely linked to spatial learning and hippocampus-dependent memory processes. For decades, ionotropic glutamate receptors have been known to play a critical role in synaptic plasticity, a form of adaptation regulating memory formation. Over the past 10 years, several groups have shown the importance of group 1 metabotropic glutamate receptor (mGluR) in successful cognitive aging. These G-protein-coupled receptors are enriched in the hippocampal formation and interact physically with other proteins in the membrane including glutamate ionotropic receptors. Synaptic plasticity is crucial to maintain cognitive abilities and long-term depression (LTD) induced by group 1 mGluR activation, which has been linked to memory in the aging brain. The translation and synthesis of proteins by mGluR-LTD modulate ionotropic receptor trafficking and expression of immediate early genes related to cognition. Fragile X syndrome, a genetic form of autism characterized by memory deficits, has been associated to mGluR receptor malfunction and aberrant activation of its downstream signaling pathways. Dysfunction of mGluR could also be involved in neurodegenerative disorders like Alzheimer’s disease (AD). Indeed, beta-amyloid, the main component of insoluble senile plaques and one of the hallmarks of AD, occludes mGluR-dependent LTD leading to diminished functional synapses. This review highlights recent findings regarding mGluR signaling, related synaptic plasticity, and their potential involvement in normal aging and neurological disorders.
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Affiliation(s)
- Caroline Ménard
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University Montreal, QC, Canada
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Siméon FG, Wendahl MT, Pike VW. Syntheses of 2-amino and 2-halothiazole derivatives as high-affinity metabotropic glutamate receptor subtype 5 ligands and potential radioligands for in vivo imaging. J Med Chem 2011; 54:901-8. [PMID: 21207959 DOI: 10.1021/jm101430m] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The structure of the potent selective mGlu(5) ligand, SP203 (1, 3-fluoro-5-[[2-(fluoromethyl)thiazol-4-yl]ethynyl]benzonitrile), was modified by replacing the 2-fluoromethyl substituent with an amino or halo substituent and by variation of substituents in the distal aromatic ring to provide a series of new high-affinity mGlu(5) ligands. In this series, among the most potent ligands obtained, the 2-chloro-thiazoles 7a and 7b and the 2-fluorothiazole 10b showed subnanomolar mGlu(5) affinity. 10b also displayed >10000-fold selectivity over all other metabotropic receptor subtypes plus a wide range of other receptors and binding sites. The 2-fluorothiazoles 10a and 10b were labeled using [(18)F]fluoride ion (t(1/2) = 109.7 min) in moderately high radiochemical yield to provide potential radioligands that may resist troublesome radiodefluorination during the imaging of brain mGlu(5) with position emission tomography. The iodo compound 9b has nanomolar affinity for mGlu(5) and may also serve as a lead to a potential (123)I-labeled ligand for imaging brain mGlu(5) with single photon emission computed tomography.
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Affiliation(s)
- Fabrice G Siméon
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3C346A, 10 Center Drive, Bethesda, MD 20892-1003, USA.
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Saggu SK, Chotaliya HP, Blumbergs PC, Casson RJ. Wallerian-like axonal degeneration in the optic nerve after excitotoxic retinal insult: an ultrastructural study. BMC Neurosci 2010; 11:97. [PMID: 20707883 PMCID: PMC2930628 DOI: 10.1186/1471-2202-11-97] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 08/13/2010] [Indexed: 12/20/2022] Open
Abstract
Background Excitotoxicity is involved in the pathogenesis of a number neurodegenerative diseases, and axonopathy is an early feature in several of these disorders. In models of excitotoxicity-associated neurological disease, an excitotoxin delivered to the central nervous system (CNS), could trigger neuronal death not only in the somatodendritic region, but also in the axonal region, via oligodendrocyte N-methyl-D-aspartate (NMDA) receptors. The retina and optic nerve, as approachable regions of the brain, provide a unique anatomical substrate to investigate the "downstream" effect of isolated excitotoxic perikaryal injury on central nervous system (CNS) axons, potentially providing information about the pathogenesis of the axonopathy in clinical neurological disorders. Herein, we provide ultrastructural information about the retinal ganglion cell (RGC) somata and their axons, both unmyelinated and myelinated, after NMDA-induced retinal injury. Male Sprague-Dawley rats were killed at 0 h, 24 h, 72 h and 7 days after injecting 20 nM NMDA into the vitreous chamber of the left eye (n = 8 in each group). Saline-injected right eyes served as controls. After perfusion fixation, dissection, resin-embedding and staining, ultrathin sections of eyes and proximal (intraorbital) and distal (intracranial) optic nerve segments were evaluated by transmission electron tomography (TEM). Results TEM demonstrated features of necrosis in RGCs: mitochondrial and endoplasmic reticulum swelling, disintegration of polyribosomes, rupture of membranous organelle and formation of myelin bodies. Ultrastructural damage in the optic nerve mimicked the changes of Wallerian degeneration; early nodal/paranodal disturbances were followed by the appearance of three major morphological variants: dark degeneration, watery degeneration and demyelination. Conclusion NMDA-induced excitotoxic retinal injury causes mainly necrotic RGC somal death with Wallerian-like degeneration of the optic nerve. Since axonal degeneration associated with perikaryal excitotoxic injury is an active, regulated process, it may be amenable to therapeutic intervention.
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Affiliation(s)
- Sarabjit K Saggu
- Ophthalmic Research Laboratories, Hanson Institute, and The University of Adelaide, SA 5000, Australia
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The GRK2 Overexpression Is a Primary Hallmark of Mitochondrial Lesions during Early Alzheimer Disease. Cardiovasc Psychiatry Neurol 2010; 2009:327360. [PMID: 20204079 PMCID: PMC2832107 DOI: 10.1155/2009/327360] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 11/16/2009] [Indexed: 12/25/2022] Open
Abstract
Increasing evidence points to vascular damage as an early contributor to the development of two leading causes of age-associated dementia, namely Alzheimer disease (AD) and AD-like pathology such as stroke. This review focuses on the role of G protein-coupled receptor kinases (GRKs) as they relate to dementia and how the cardio and cerebrovasculature is involved in AD pathogenesis. The exploration of GRKs in AD pathogenesis may help bridge gaps in our understanding of the heart-brain connection in relation to neurovisceral damage and vascular complications of AD. The a priori basis for this inquiry stems from the fact that kinases of this family regulate numerous receptor functions in the brain, myocardium and elsewhere. The aim of this review is to discuss the finding of GRK2 overexpression in the context of early AD pathogenesis. Also, we consider the consequences for this overexpression as a loss of G-protein coupled receptor (GPCR) regulation, as well as suggest a potential role for GPCRs and GRKs in a unifying theory of AD pathogenesis through the cerebrovasculature. Finally, we synthesize this newer information in an attempt to put it into context with GRKs as regulators of cellular function, which makes these proteins potential diagnostic and therapeutic targets for future pharmacological intervention.
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Obrenovich ME, Morales LA, Cobb CJ, Shenk JC, Méndez GM, Fischbach K, Smith MA, Qasimov EK, Perry G, Aliev G. Insights into cerebrovascular complications and Alzheimer disease through the selective loss of GRK2 regulation. J Cell Mol Med 2008; 13:853-65. [PMID: 19292735 PMCID: PMC2919803 DOI: 10.1111/j.1582-4934.2008.00512.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Alzheimer disease (AD) and stroke are two leading causes of age-associated dementia. Increasing evidence points to vascular damage as an early contributor to the development of AD and AD-like pathology. In this review, we discuss the role of G protein-coupled receptor kinase 2 (GRK2) as it relates to individuals affected by AD and how the cardiovasculature plays a role in AD pathogenesis. The possible involvement of GRKs in AD pathogenesis is an interesting notion, which may help bridge the gap in our understanding of the heart–brain connection in relation to neurovisceral damage and vascular complications in AD, since kinases of this family are known to regulate numerous receptor functions both in the brain, myocardium, and elsewhere. The aim of this review is to discuss our findings of overexpression of GRK2 in the context of the early pathogenesis of AD, because increased levels of GRK2 immunoreactivity were found in vulnerable neurons of AD patients as well as in a two-vessel occlusion (2-VO) mammalian model of ischaemia. Also, we consider the consequences for this overexpression as a loss of G-protein coupled receptor (GPCR) regulation, as well as suggest a potential role for GPCRs and GRKs in a unifying theory of AD pathogenesis, particularly in the context of cerebrovascular disease. We synthesize this newer information and attempt to put it into context with GRKs as regulators of diverse physiological cellular functions that could be appropriate targets for future pharmacological intervention.
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Affiliation(s)
- Mark E Obrenovich
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
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Shetty HU, Zoghbi SS, Siméon FG, Liow JS, Brown AK, Kannan P, Innis RB, Pike VW. Radiodefluorination of 3-fluoro-5-(2-(2-[18F](fluoromethyl)-thiazol-4-yl)ethynyl)benzonitrile ([18F]SP203), a radioligand for imaging brain metabotropic glutamate subtype-5 receptors with positron emission tomography, occurs by glutathionylation in rat brain. J Pharmacol Exp Ther 2008; 327:727-35. [PMID: 18806125 DOI: 10.1124/jpet.108.143347] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Metabotropic glutamate subtype-5 receptors (mGluR5) are implicated in several neuropsychiatric disorders. Positron emission tomography (PET) with a suitable radioligand may enable monitoring of regional brain mGluR5 density before and during treatments. We have developed a new radioligand, 3-fluoro-5-(2-(2-[(18)F](fluoromethyl)thiazol-4-yl)ethynyl)benzonitrile ([(18)F]SP203), for imaging brain mGluR5 in monkey and human. In monkey, radioactivity was observed in bone, showing release of [(18)F]-fluoride ion from [(18)F]SP203. This defluorination was not inhibited by disulfiram, a potent inhibitor of CYP2E1. PET confirmed bone uptake of radioactivity and therefore defluorination of [(18)F]SP203 in rats. To understand the biochemical basis for defluorination, we administered [(18)F]SP203 plus SP203 in rats for ex vivo analysis of metabolites. Radio-high-performance liquid chromatography detected [(18)F]fluoride ion as a major radiometabolite in both brain extract and urine. Incubation of [(18)F]SP203 with brain homogenate also generated this radiometabolite, whereas no metabolism was detected in whole blood in vitro. Liquid chromatography-mass spectrometry analysis of the brain extract detected m/z 548 and 404 ions, assignable to the [M + H](+) of S-glutathione (SP203Glu) and N-acetyl-S-l-cysteine (SP203Nac) conjugates of SP203, respectively. In urine, only the [M + H](+) of SP203Nac was detected. Mass spectrometry/mass spectrometry and multi-stage mass spectrometry analyses of each metabolite yielded product ions consistent with its proposed structure, including the former fluoromethyl group as the site of conjugation. Metabolite structures were confirmed by similar analyses of SP203Glu and SP203Nac, prepared by glutathione S-transferase reaction and chemical synthesis, respectively. Thus, glutathionylation at the 2-fluoromethyl group is responsible for the radiodefluorination of [(18)F]SP203 in rat. This study provides the first demonstration of glutathione-promoted radiodefluorination of a PET radioligand.
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Affiliation(s)
- H Umesha Shetty
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1003, USA.
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Rousseaux CG. A Review of Glutamate Receptors II: Pathophysiology and Pathology. J Toxicol Pathol 2008. [DOI: 10.1293/tox.21.133] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Colin G. Rousseaux
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of Ottawa
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Atlasz T, Babai N, Reglodi D, Kiss P, Tamas A, Bari F, Domoki F, Gabriel R. Diazoxide is protective in the rat retina against ischemic injury induced by bilateral carotid occlusion and glutamate-induced degeneration. Neurotox Res 2007; 12:105-11. [DOI: 10.1007/bf03033919] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
Neurotoxins represent unique chemical tools, providing a means to 1) gain insight into cellular mechanisms of apopotosis and necrosis, 2) achieve a morphological template for studies otherwise unattainable, 3) specifically produce a singular phenotype of denervation, and 4) provide the starting point to delve into processes and mechanisms of nerve regeneration and sprouting. There are many other notable uses of neurotoxins in neuroscience research, and ever more being discovered each year. The objective of this review paper is to highlight the broad areas of neuroscience in which neurotoxins and neurotoxicity mechanism come into play. This shifts the focus away from neurotoxins per se, and onto the major problems under study today. Neurotoxins broadly defined are used to explore neurodegenerative disorders, psychiatric disorders and substance use disorders. Neurotoxic mechanisms relating to protein aggregates are indigenous to Alzheimer disease, Parkinson's disease. NeuroAIDS is a disorder in which microglia and macrophages have enormous import. The gap between the immune system and nervous system has been bridged, as neuroinflammation is now considered to be part of the neurodegenerative process. Related mechanisms now arise in the process of neurogenesis. Accordingly, the entire spectrum of neuroscience is within the purview of neurotoxins and neurotoxicity mechanisms. Highlights on discoveries in the areas noted, and on selective neurotoxins, are included, mainly from the past 2 to 3 years.
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Affiliation(s)
- Juan Segura-Aguilar
- Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Casilla 70000, Santiago, Chile.
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Small DH. Biochemical, cellular and behavioural aspects of neurodegeneration: the view from down under. Neurotox Res 2005; 7:1-3. [PMID: 15639793 DOI: 10.1007/bf03033771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- David H Small
- Department of Biochemistry and Molecular Biology and Monash University Centre for Brain and Behaviour, Monash University, Victoria 3800, Australia.
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