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Pisciottani A, Croci L, Lauria F, Marullo C, Savino E, Ambrosi A, Podini P, Marchioretto M, Casoni F, Cremona O, Taverna S, Quattrini A, Cioni JM, Viero G, Codazzi F, Consalez GG. Neuronal models of TDP-43 proteinopathy display reduced axonal translation, increased oxidative stress, and defective exocytosis. Front Cell Neurosci 2023; 17:1253543. [PMID: 38026702 PMCID: PMC10679756 DOI: 10.3389/fncel.2023.1253543] [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: 07/05/2023] [Accepted: 10/13/2023] [Indexed: 12/01/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive, lethal neurodegenerative disease mostly affecting people around 50-60 years of age. TDP-43, an RNA-binding protein involved in pre-mRNA splicing and controlling mRNA stability and translation, forms neuronal cytoplasmic inclusions in an overwhelming majority of ALS patients, a phenomenon referred to as TDP-43 proteinopathy. These cytoplasmic aggregates disrupt mRNA transport and localization. The axon, like dendrites, is a site of mRNA translation, permitting the local synthesis of selected proteins. This is especially relevant in upper and lower motor neurons, whose axon spans long distances, likely accentuating their susceptibility to ALS-related noxae. In this work we have generated and characterized two cellular models, consisting of virtually pure populations of primary mouse cortical neurons expressing a human TDP-43 fusion protein, wt or carrying an ALS mutation. Both forms facilitate cytoplasmic aggregate formation, unlike the corresponding native proteins, giving rise to bona fide primary culture models of TDP-43 proteinopathy. Neurons expressing TDP-43 fusion proteins exhibit a global impairment in axonal protein synthesis, an increase in oxidative stress, and defects in presynaptic function and electrical activity. These changes correlate with deregulation of axonal levels of polysome-engaged mRNAs playing relevant roles in the same processes. Our data support the emerging notion that deregulation of mRNA metabolism and of axonal mRNA transport may trigger the dying-back neuropathy that initiates motor neuron degeneration in ALS.
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Affiliation(s)
- Alessandra Pisciottani
- Faculty of Medicine and Surgery, Università Vita-Salute San Raffaele, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Laura Croci
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Fabio Lauria
- Institute of Biophysics, CNR Unit at Trento, Povo, Italy
| | - Chiara Marullo
- Faculty of Medicine and Surgery, Università Vita-Salute San Raffaele, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Elisa Savino
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Alessandro Ambrosi
- Faculty of Medicine and Surgery, Università Vita-Salute San Raffaele, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Paola Podini
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | | | - Filippo Casoni
- Faculty of Medicine and Surgery, Università Vita-Salute San Raffaele, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Ottavio Cremona
- Faculty of Medicine and Surgery, Università Vita-Salute San Raffaele, Milan, Italy
| | - Stefano Taverna
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Angelo Quattrini
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Jean-Michel Cioni
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | | | - Franca Codazzi
- Faculty of Medicine and Surgery, Università Vita-Salute San Raffaele, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - G. Giacomo Consalez
- Faculty of Medicine and Surgery, Università Vita-Salute San Raffaele, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
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2
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Colgan LA, Parra-Bueno P, Holman HL, Tu X, Jain A, Calubag MF, Misler JA, Gary C, Oz G, Suponitsky-Kroyter I, Okaz E, Yasuda R. Dual Regulation of Spine-Specific and Synapse-to-Nucleus Signaling by PKCδ during Plasticity. J Neurosci 2023; 43:5432-5447. [PMID: 37277178 PMCID: PMC10376934 DOI: 10.1523/jneurosci.0208-22.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 05/18/2023] [Accepted: 05/27/2023] [Indexed: 06/07/2023] Open
Abstract
The activity-dependent plasticity of synapses is believed to be the cellular basis of learning. These synaptic changes are mediated through the coordination of local biochemical reactions in synapses and changes in gene transcription in the nucleus to modulate neuronal circuits and behavior. The protein kinase C (PKC) family of isozymes has long been established as critical for synaptic plasticity. However, because of a lack of suitable isozyme-specific tools, the role of the novel subfamily of PKC isozymes is largely unknown. Here, through the development of fluorescence lifetime imaging-fluorescence resonance energy transfer activity sensors, we investigate novel PKC isozymes in synaptic plasticity in CA1 pyramidal neurons of mice of either sex. We find that PKCδ is activated downstream of TrkB and DAG production, and that the spatiotemporal nature of its activation depends on the plasticity stimulation. In response to single-spine plasticity, PKCδ is activated primarily in the stimulated spine and is required for local expression of plasticity. However, in response to multispine stimulation, a long-lasting and spreading activation of PKCδ scales with the number of spines stimulated and, by regulating cAMP response-element binding protein activity, couples spine plasticity to transcription in the nucleus. Thus, PKCδ plays a dual functional role in facilitating synaptic plasticity.SIGNIFICANCE STATEMENT Synaptic plasticity, or the ability to change the strength of the connections between neurons, underlies learning and memory and is critical for brain health. The protein kinase C (PKC) family is central to this process. However, understanding how these kinases work to mediate plasticity has been limited by a lack of tools to visualize and perturb their activity. Here, we introduce and use new tools to reveal a dual role for PKCδ in facilitating local synaptic plasticity and stabilizing this plasticity through spine-to-nucleus signaling to regulate transcription. This work provides new tools to overcome limitations in studying isozyme-specific PKC function and provides insight into molecular mechanisms of synaptic plasticity.
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Affiliation(s)
- Lesley A Colgan
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Paula Parra-Bueno
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Heather L Holman
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Xun Tu
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Anant Jain
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Mariah F Calubag
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Jaime A Misler
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Chancellor Gary
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Goksu Oz
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Irena Suponitsky-Kroyter
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Elwy Okaz
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Ryohei Yasuda
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
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3
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Rosato C, Bettegazzi B, Intagliata P, Balbontin Arenas M, Zacchetti D, Lanati A, Zerbini G, Bandello F, Grohovaz F, Codazzi F. Redox and Calcium Alterations of a Müller Cell Line Exposed to Diabetic Retinopathy-Like Environment. Front Cell Neurosci 2022; 16:862325. [PMID: 35370555 PMCID: PMC8972164 DOI: 10.3389/fncel.2022.862325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 02/25/2022] [Indexed: 11/13/2022] Open
Abstract
Diabetic retinopathy (DR) is a common complication of diabetes mellitus and is the major cause of vision loss in the working-age population. Although DR is traditionally considered a microvascular disease, an increasing body of evidence suggests that neurodegeneration is an early event that occurs even before the manifestation of vasculopathy. Accordingly, attention should be devoted to the complex neurodegenerative process occurring in the diabetic retina, also considering possible functional alterations in non-neuronal cells, such as glial cells. In this work, we investigate functional changes in Müller cells, the most abundant glial population present within the retina, under experimental conditions that mimic those observed in DR patients. More specifically, we investigated on the Müller cell line rMC-1 the effect of high glucose, alone or associated with activation processes and oxidative stress. By fluorescence microscopy and cellular assays approaches, we studied the alteration of functional properties, such as reactive oxygen species production, antioxidant response, calcium homeostasis, and mitochondrial membrane potential. Our results demonstrate that hyperglycaemic-like condition per se is well-tolerated by rMC-1 cells but makes them more susceptible to a pro-inflammatory environment, exacerbating the effects of this stressful condition. More specifically, rMC-1 cells exposed to high glucose decrease their ability to counteract oxidative stress, with consequent toxic effects. In conclusion, our study offers new insights into Müller cell pathophysiology in DR and proposes a novel in vitro model which may prove useful to further investigate potential antioxidant and anti-inflammatory molecules for the prevention and/or treatment of DR.
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Affiliation(s)
- Clarissa Rosato
- Vita-Salute San Raffaele University, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Barbara Bettegazzi
- Vita-Salute San Raffaele University, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Pia Intagliata
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | | | - Daniele Zacchetti
- Vita-Salute San Raffaele University, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Antonella Lanati
- Vita-Salute San Raffaele University, Milan, Italy
- Valore Qualità, Pavia, Italy
| | - Gianpaolo Zerbini
- Complications of Diabetes Unit, Diabetes Research Institute (DRI), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Francesco Bandello
- Vita-Salute San Raffaele University, Milan, Italy
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Fabio Grohovaz
- Vita-Salute San Raffaele University, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Franca Codazzi
- Vita-Salute San Raffaele University, Milan, Italy
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
- *Correspondence: Franca Codazzi
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Menegaz D, Hagan DW, Almaça J, Cianciaruso C, Rodriguez-Diaz R, Molina J, Dolan RM, Becker MW, Schwalie PC, Nano R, Lebreton F, Kang C, Sah R, Gaisano HY, Berggren PO, Baekkeskov S, Caicedo A, Phelps EA. Mechanism and effects of pulsatile GABA secretion from cytosolic pools in the human beta cell. Nat Metab 2019; 1:1110-1126. [PMID: 32432213 PMCID: PMC7236889 DOI: 10.1038/s42255-019-0135-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Pancreatic beta cells synthesize and secrete the neurotransmitter γ-aminobutyric acid (GABA) as a paracrine and autocrine signal to help regulate hormone secretion and islet homeostasis. Islet GABA release has classically been described as a secretory vesicle-mediated event. Yet, a limitation of the hypothesized vesicular GABA release from islets is the lack of expression of a vesicular GABA transporter in beta cells. Consequentially, GABA accumulates in the cytosol. Here we provide evidence that the human beta cell effluxes GABA from a cytosolic pool in a pulsatile manner, imposing a synchronizing rhythm on pulsatile insulin secretion. The volume regulatory anion channel (VRAC), functionally encoded by LRRC8A or Swell1, is critical for pulsatile GABA secretion. GABA content in beta cells is depleted and secretion is disrupted in islets from type 1 and type 2 diabetic patients, suggesting that loss of GABA as a synchronizing signal for hormone output may correlate with diabetes pathogenesis.
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Affiliation(s)
- Danusa Menegaz
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | - D Walker Hagan
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Joana Almaça
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Chiara Cianciaruso
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Rayner Rodriguez-Diaz
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Judith Molina
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Robert M Dolan
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Matthew W Becker
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Petra C Schwalie
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Rita Nano
- Pancreatic Islet Processing Facility, Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Fanny Lebreton
- Cell Isolation and Transplantation Center, Faculty of Medicine, Department of Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Chen Kang
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, USA
| | - Rajan Sah
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, USA
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, USA
| | - Herbert Y Gaisano
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Per-Olof Berggren
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- The Rolf Luft Research Center for Diabetes & Endocrinology, Karolinska Institutet, Stockholm, Sweden
- Division of Integrative Biosciences and Biotechnology, WCU Program, University of Science and Technology, Pohang, Korea
| | - Steinunn Baekkeskov
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
- Departments of Medicine and Microbiology/Immunology, Diabetes Center, University of California San Francisco, San Francisco, CA, USA.
| | - Alejandro Caicedo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA.
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL, USA.
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL, USA.
- Program in Neuroscience, Miller School of Medicine, University of Miami, Miami, FL, USA.
| | - Edward A Phelps
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
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5
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Reiner A, Levitz J. Glutamatergic Signaling in the Central Nervous System: Ionotropic and Metabotropic Receptors in Concert. Neuron 2019; 98:1080-1098. [PMID: 29953871 DOI: 10.1016/j.neuron.2018.05.018] [Citation(s) in RCA: 338] [Impact Index Per Article: 67.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/19/2018] [Accepted: 05/10/2018] [Indexed: 12/28/2022]
Abstract
Glutamate serves as both the mammalian brain's primary excitatory neurotransmitter and as a key neuromodulator to control synapse and circuit function over a wide range of spatial and temporal scales. This functional diversity is decoded by two receptor families: ionotropic glutamate receptors (iGluRs) and metabotropic glutamate receptors (mGluRs). The challenges posed by the complexity and physiological importance of each of these subtypes has limited our appreciation and understanding of how these receptors work in concert. In this review, by comparing both receptor families with a focus on their crosstalk, we argue for a more holistic understanding of neural glutamate signaling.
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Affiliation(s)
- Andreas Reiner
- Department of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany.
| | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA.
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6
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Kumar M, John M, Madhavan M, James J, Omkumar RV. Alteration in the phosphorylation status of NMDA receptor GluN2B subunit by activation of both NMDA receptor and L-type voltage gated calcium channel. Neurosci Lett 2019; 709:134343. [PMID: 31279915 DOI: 10.1016/j.neulet.2019.134343] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/03/2019] [Accepted: 06/18/2019] [Indexed: 01/27/2023]
Abstract
Calcium influx through N-methyl-D-aspartate receptors (NMDAR) and voltage-gated calcium channels (VGCC) play major roles in postsynaptic signaling mechanisms. NMDAR subunit GluN2B is phosphorylated at Ser1303. Phosphorylation at this site is a prominent event in cell culture systems as well as in vivo. However, the functional significance of phosphorylation at this site is not completely understood. In this study, we compared the effect of calcium signaling through NMDAR and VGCC on the phosphorylation status of GluN2B-Ser1303 in the rat in vivo. VGCC was activated by intraperitoneal (IP) injection of the activator, BayK8644 and NMDAR was activated by intracerebroventricular (ICV) injection of NMDA in separate experimental groups. We found that the level of phospho-GluN2B-Ser1303 in the cortex and in the hippocampus increased in response to activation of either channel. The effects could be prevented by prior ICV administration of the specific blockers of these channels such as MK-801 for NMDAR and nifedipine for VGCC. The effect was also blocked by pretreatment with ICV administration of KN-93 indicating that it is mediated through CaM kinase. Both during NMDAR activation and VGCC activation, cell survival associated signals such as phospho-AKT and phospho-CREB showed decrease, consistent with activation of cell death pathways during these treatments. We conclude that under in vivo conditions, calcium influx through either NMDAR or VGCC activates CaM kinase, which in turn phosphorylates GluN2B-Ser1303.
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Affiliation(s)
- Mantosh Kumar
- Molecular Neurobiology Division, Rajiv Gandhi Centre for Biotechnology, Thycaud, P.O., Thiruvananthapuram-695014, Kerala, India; Research Scholar, University of Kerala, India
| | - Mathew John
- Molecular Neurobiology Division, Rajiv Gandhi Centre for Biotechnology, Thycaud, P.O., Thiruvananthapuram-695014, Kerala, India
| | - Mayadevi Madhavan
- Molecular Neurobiology Division, Rajiv Gandhi Centre for Biotechnology, Thycaud, P.O., Thiruvananthapuram-695014, Kerala, India
| | - Jackson James
- Neuro Stem Cell Biology Lab, Rajiv Gandhi Centre for Biotechnology, India
| | - Ramakrishnapillai V Omkumar
- Molecular Neurobiology Division, Rajiv Gandhi Centre for Biotechnology, Thycaud, P.O., Thiruvananthapuram-695014, Kerala, India.
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7
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Tulli S, Del Bondio A, Baderna V, Mazza D, Codazzi F, Pierson TM, Ambrosi A, Nolte D, Goizet C, Toro C, Baets J, Deconinck T, DeJonghe P, Mandich P, Casari G, Maltecca F. Pathogenic variants in the AFG3L2 proteolytic domain cause SCA28 through haploinsufficiency and proteostatic stress-driven OMA1 activation. J Med Genet 2019; 56:499-511. [PMID: 30910913 PMCID: PMC6678042 DOI: 10.1136/jmedgenet-2018-105766] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/05/2019] [Accepted: 03/03/2019] [Indexed: 12/18/2022]
Abstract
Background Spinocerebellar ataxia type 28 (SCA28) is a dominantly inherited neurodegenerative disease caused by pathogenic variants in AFG3L2. The AFG3L2 protein is a subunit of mitochondrial m-AAA complexes involved in protein quality control. Objective of this study was to determine the molecular mechanisms of SCA28, which has eluded characterisation to date. Methods We derived SCA28 patient fibroblasts carrying different pathogenic variants in the AFG3L2 proteolytic domain (missense: the newly identified p.F664S and p.M666T, p.G671R, p.Y689H and a truncating frameshift p.L556fs) and analysed multiple aspects of mitochondrial physiology. As reference of residual m-AAA activity, we included SPAX5 patient fibroblasts with homozygous p.Y616C pathogenic variant, AFG3L2+/− HEK293 T cells by CRISPR/Cas9-genome editing and Afg3l2−/− murine fibroblasts. Results We found that SCA28 cells carrying missense changes have normal levels of assembled m-AAA complexes, while the cells with a truncating pathogenic variant had only half of this amount. We disclosed inefficient mitochondrial fusion in SCA28 cells caused by increased OPA1 processing operated by hyperactivated OMA1. Notably, we found altered mitochondrial proteostasis to be the trigger of OMA1 activation in SCA28 cells, with pharmacological attenuation of mitochondrial protein synthesis resulting in stabilised levels of OMA1 and OPA1 long forms, which rescued mitochondrial fusion efficiency. Secondary to altered mitochondrial morphology, mitochondrial calcium uptake resulted decreased in SCA28 cells. Conclusion Our data identify the earliest events in SCA28 pathogenesis and open new perspectives for therapy. By identifying similar mitochondrial phenotypes between SCA28 cells and AFG3L2+/− cells, our results support haploinsufficiency as the mechanism for the studied pathogenic variants.
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Affiliation(s)
- Susanna Tulli
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Andrea Del Bondio
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Valentina Baderna
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Davide Mazza
- Experimental Imaging Center, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Franca Codazzi
- Università Vita-Salute San Raffaele, Milan, Italy.,Division of Neuroscience, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Tyler Mark Pierson
- Departments of Pediatrics and Neurology and the Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | | | - Dagmar Nolte
- Department of Medicine, Institute for Human Genetics, Justus-Liebig-University Giessen, Giessen, Germany
| | - Cyril Goizet
- Centre de Reference Neurogenetique, Service de Genetique Medicale, CHU Bordeaux, Bordeaux, France.,Laboratoire MRGM, INSERM U1211, Bordeaux, France
| | - Camilo Toro
- Undiagnosed Disease Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland, USA
| | - Jonathan Baets
- Neurogenetics Group and Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium.,Neuromuscular Reference Centre, Antwerp University Hospital, Antwerpen, Belgium
| | - Tine Deconinck
- Neurogenetics Group and Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium.,Neuromuscular Reference Centre, Antwerp University Hospital, Antwerpen, Belgium
| | - Peter DeJonghe
- Neurogenetics Group and Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium.,Neuromuscular Reference Centre, Antwerp University Hospital, Antwerpen, Belgium
| | - Paola Mandich
- DINOGMI, University of Genoa and IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Giorgio Casari
- Università Vita-Salute San Raffaele, Milan, Italy.,Telethon Institute of Genetics and Medicine, Naples, Italy
| | - Francesca Maltecca
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
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8
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McGann JC, Mandel G. Neuronal activity induces glutathione metabolism gene expression in astrocytes. Glia 2018; 66:2024-2039. [PMID: 30043519 DOI: 10.1002/glia.23455] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 04/03/2018] [Accepted: 04/24/2018] [Indexed: 12/30/2022]
Abstract
The idea that astrocytes provide support for neurons has a long history, but whether neurons play an instructive role in these processes is poorly understood. To address this question, we co-culture astrocytes with genetically labeled neurons, permitting their separation by flow cytometry, and test whether the presence of neurons influences the astrocyte transcriptome. We find that numerous pathways are regulated in the co-cultured astrocytes, in a time-dependent matter coincident with synaptic maturation. In particular, the induction of glutathione metabolic genes is prominent, resulting in increased glutathione production. We show that the induction of the glutathione pathway is mediated by astrocytic metabotropic glutamate receptors. Using a candidate approach, we identify direct binding of the nuclear factor E2-related factor, NRF2, to several of the induced genes. Blocking nuclear accumulation of astrocytic NRF2 abolishes neuron-induced glutathione gene induction and glutathione production. Our results suggest that astrocyte transcriptional and metabolic profiles are tightly coupled to the activity of neurons, consistent with the model that astrocytes dynamically support healthy brain function.
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Affiliation(s)
- James C McGann
- Oregon Health and Science, Sam Jackson Park Road, Ortland, Oregon 97239
| | - Gail Mandel
- Oregon Health and Science, Sam Jackson Park Road, Ortland, Oregon 97239
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9
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Phelps EA, Cianciaruso C, Santo-Domingo J, Pasquier M, Galliverti G, Piemonti L, Berishvili E, Burri O, Wiederkehr A, Hubbell JA, Baekkeskov S. Advances in pancreatic islet monolayer culture on glass surfaces enable super-resolution microscopy and insights into beta cell ciliogenesis and proliferation. Sci Rep 2017; 7:45961. [PMID: 28401888 PMCID: PMC5388888 DOI: 10.1038/srep45961] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 03/08/2017] [Indexed: 12/16/2022] Open
Abstract
A robust and reproducible method for culturing monolayers of adherent and well-spread primary islet cells on glass coverslips is required for detailed imaging studies by super-resolution and live-cell microscopy. Guided by an observation that dispersed islet cells spread and adhere well on glass surfaces in neuronal co-culture and form a monolayer of connected cells, we demonstrate that in the absence of neurons, well-defined surface coatings combined with components of neuronal culture media collectively support robust attachment and growth of primary human or rat islet cells as monolayers on glass surfaces. The islet cell monolayer cultures on glass stably maintain distinct mono-hormonal insulin+, glucagon+, somatostatin+ and PP+ cells and glucose-responsive synchronized calcium signaling as well as expression of the transcription factors Pdx-1 and NKX-6.1 in beta cells. This technical advance enabled detailed observation of sub-cellular processes in primary human and rat beta cells by super-resolution microscopy. The protocol is envisaged to have broad applicability to sophisticated analyses of pancreatic islet cells that reveal new biological insights, as demonstrated by the identification of an in vitro protocol that markedly increases proliferation of primary beta cells and is associated with a reduction in ciliated, ostensibly proliferation-suppressed beta cells.
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Affiliation(s)
- Edward A Phelps
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Chiara Cianciaruso
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.,Graduate Program in Biotechnology and Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Jaime Santo-Domingo
- Nestlé Institute of Health Sciences S.A., EPFL Innovation Park, CH-1015 Lausanne, Switzerland
| | - Miriella Pasquier
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Gabriele Galliverti
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.,Graduate Program in Biotechnology and Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.,Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Lorenzo Piemonti
- Pancreatic Islet Processing Facility, Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Ekaterine Berishvili
- Cell Isolation and Transplantation Center, Faculty of Medicine, Department of Surgery, Geneva University Hospitals and University of Geneva, CH-1211 Geneva, Switzerland
| | - Olivier Burri
- BioImaging and Optics Core Facility, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Andreas Wiederkehr
- Nestlé Institute of Health Sciences S.A., EPFL Innovation Park, CH-1015 Lausanne, Switzerland
| | - Jeffrey A Hubbell
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.,Graduate Program in Biotechnology and Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.,Institute for Molecular Engineering, University of Chicago, Chicago, IL 60615, USA
| | - Steinunn Baekkeskov
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.,Graduate Program in Biotechnology and Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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10
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Phelps EA, Cianciaruso C, Michael IP, Pasquier M, Kanaani J, Nano R, Lavallard V, Billestrup N, Hubbell JA, Baekkeskov S. Aberrant Accumulation of the Diabetes Autoantigen GAD65 in Golgi Membranes in Conditions of ER Stress and Autoimmunity. Diabetes 2016; 65:2686-99. [PMID: 27284108 PMCID: PMC5001175 DOI: 10.2337/db16-0180] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 05/27/2016] [Indexed: 02/06/2023]
Abstract
Pancreatic islet β-cells are particularly susceptible to endoplasmic reticulum (ER) stress, which is implicated in β-cell dysfunction and loss during the pathogenesis of type 1 diabetes (T1D). The peripheral membrane protein GAD65 is an autoantigen in human T1D. GAD65 synthesizes γ-aminobutyric acid, an important autocrine and paracrine signaling molecule and a survival factor in islets. We show that ER stress in primary β-cells perturbs the palmitoylation cycle controlling GAD65 endomembrane distribution, resulting in aberrant accumulation of the palmitoylated form in trans-Golgi membranes. The palmitoylated form has heightened immunogenicity, exhibiting increased uptake by antigen-presenting cells and T-cell stimulation compared with the nonpalmitoylated form. Similar accumulation of GAD65 in Golgi membranes is observed in human β-cells in pancreatic sections from GAD65 autoantibody-positive individuals who have not yet progressed to clinical onset of T1D and from patients with T1D with residual β-cell mass and ongoing T-cell infiltration of islets. We propose that aberrant accumulation of immunogenic GAD65 in Golgi membranes facilitates inappropriate presentation to the immune system after release from stressed and/or damaged β-cells, triggering autoimmunity.
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Affiliation(s)
- Edward A Phelps
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Chiara Cianciaruso
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland Graduate Program in Biotechnology and Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Iacovos P Michael
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Miriella Pasquier
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jamil Kanaani
- Departments of Medicine, Microbiology and Immunology and Diabetes Center, University of California San Francisco, San Francisco, CA
| | - Rita Nano
- Diabetes Research Institute, IRCCS, Pancreatic Islet Processing Facility, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Vanessa Lavallard
- Cell Isolation and Transplantation Center, Faculty of Medicine, Department of Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Nils Billestrup
- Section of Cellular and Metabolic Research, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jeffrey A Hubbell
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland Graduate Program in Biotechnology and Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland Institute for Molecular Engineering, University of Chicago, Chicago, IL
| | - Steinunn Baekkeskov
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland Graduate Program in Biotechnology and Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland Departments of Medicine, Microbiology and Immunology and Diabetes Center, University of California San Francisco, San Francisco, CA
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11
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Kelher MR, McLaughlin NJD, Banerjee A, Elzi DJ, Gamboni F, Khan SY, Meng X, Mitra S, Silliman CC. LysoPCs induce Hck- and PKCδ-mediated activation of PKCγ causing p47phox phosphorylation and membrane translocation in neutrophils. J Leukoc Biol 2016; 101:261-273. [PMID: 27531930 DOI: 10.1189/jlb.3a0813-420rrr] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 07/20/2016] [Accepted: 07/22/2016] [Indexed: 11/24/2022] Open
Abstract
Lysophosphatidylcholines (lysoPCs) are effective polymorphonuclear neutrophil (PMN) priming agents implicated in transfusion-related acute lung injury (TRALI). LysoPCs cause ligation of the G2A receptor, cytosolic Ca2+ flux, and activation of Hck. We hypothesize that lysoPCs induce Hck-dependent activation of protein kinase C (PKC), resulting in phosphorylation and membrane translocation of 47 kDa phagocyte oxidase protein (p47phox). PMNs, human or murine, were primed with lysoPCs and were smeared onto slides and examined by digital microscopy or separated into subcellular fractions or whole-cell lysates. Proteins were immunoprecipitated or separated by polyacrylamide gel electrophoresis and immunoblotted for proteins of interest. Wild-type (WT) and PKCγ knockout (KO) mice were used in a 2-event model of TRALI. LysoPCs induced Hck coprecipitation with PKCδ and PKCγ and the PKCδ:PKCγ complex also had a fluorescence resonance energy transfer (FRET)+ interaction with lipid rafts and Wiskott-Aldrich syndrome protein family verprolin-homologous protein 2 (WAVE2). PKCγ then coprecipitated with p47phox Immunoblotting, immunoprecipitation (IP), specific inhibitors, intracellular depletion of PKC isoforms, and PMNs from PKCγ KO mice demonstrated that Hck elicited activation/Tyr phosphorylation (Tyr311 and Tyr525) of PKCδ, which became Thr phosphorylated (Thr507). Activated PKCδ then caused activation of PKCγ, both by Tyr phosphorylation (Τyr514) and Ser phosphorylation, which induced phosphorylation and membrane translocation of p47phox In PKCγ KO PMNs, lysoPCs induced Hck translocation but did not evidence a FRET+ interaction between PKCδ and PKCγ nor prime PMNs. In WT mice, lysoPCs served as the second event in a 2-event in vivo model of TRALI but did not induce TRALI in PKCγ KO mice. We conclude that lysoPCs prime PMNs through Hck-dependent activation of PKCδ, which stimulates PKCγ, resulting in translocation of phosphorylated p47phox.
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Affiliation(s)
- Marguerite R Kelher
- Research Laboratory, Bonfils Blood Center, Denver, Colorado, USA.,Department of Surgery, School of Medicine, University of Colorado Denver, Aurora, Colorado, USA; and
| | - Nathan J D McLaughlin
- Department of Surgery, School of Medicine, University of Colorado Denver, Aurora, Colorado, USA; and
| | - Anirban Banerjee
- Department of Surgery, School of Medicine, University of Colorado Denver, Aurora, Colorado, USA; and
| | - David J Elzi
- Research Laboratory, Bonfils Blood Center, Denver, Colorado, USA.,Department of Surgery, School of Medicine, University of Colorado Denver, Aurora, Colorado, USA; and
| | - Fabia Gamboni
- Department of Surgery, School of Medicine, University of Colorado Denver, Aurora, Colorado, USA; and
| | - Samina Y Khan
- Department of Pediatrics, School of Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | - Xianzhong Meng
- Department of Surgery, School of Medicine, University of Colorado Denver, Aurora, Colorado, USA; and
| | - Sanchayita Mitra
- Department of Surgery, School of Medicine, University of Colorado Denver, Aurora, Colorado, USA; and
| | - Christopher C Silliman
- Research Laboratory, Bonfils Blood Center, Denver, Colorado, USA; .,Department of Surgery, School of Medicine, University of Colorado Denver, Aurora, Colorado, USA; and.,Department of Pediatrics, School of Medicine, University of Colorado Denver, Aurora, Colorado, USA
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12
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Hullinger R, Puglielli L. Molecular and cellular aspects of age-related cognitive decline and Alzheimer's disease. Behav Brain Res 2016; 322:191-205. [PMID: 27163751 DOI: 10.1016/j.bbr.2016.05.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/19/2016] [Accepted: 05/03/2016] [Indexed: 01/14/2023]
Abstract
As the population of people aged 60 or older continues to rise, it has become increasingly important to understand the molecular basis underlying age-related cognitive decline. In fact, a better understanding of aging biology will help us identify ways to maintain high levels of cognitive functioning throughout the aging process. Many cellular and molecular aspects of brain aging are shared with other organ systems; however, certain age-related changes are unique to the nervous system due to its structural, cellular and molecular complexity. Importantly, the brain appears to show differential changes throughout the aging process, with certain regions (e.g. frontal and temporal regions) being more vulnerable than others (e.g. brain stem). Within the medial temporal lobe, the hippocampus is especially susceptible to age-related changes. The important role of the hippocampus in age-related cognitive decline and in vulnerability to disease processes such as Alzheimer's disease has prompted this review, which will focus on the complexity of changes that characterize aging, and on the molecular connections that exist between normal aging and Alzheimer's disease. Finally, it will discuss behavioral interventions and emerging insights for promoting healthy cognitive aging.
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Affiliation(s)
- Rikki Hullinger
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Luigi Puglielli
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705, USA; Wisconsin Alzheimer's Disease Research Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Geriatric Research Education Clinical Center, VA Medical Center, Madison, WI 53705, USA.
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13
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Banerjee A, Wang HY, Borgmann-Winter KE, MacDonald ML, Kaprielian H, Stucky A, Kvasic J, Egbujo C, Ray R, Talbot K, Hemby SE, Siegel SJ, Arnold SE, Sleiman P, Chang X, Hakonarson H, Gur RE, Hahn CG. Src kinase as a mediator of convergent molecular abnormalities leading to NMDAR hypoactivity in schizophrenia. Mol Psychiatry 2015; 20:1091-100. [PMID: 25330739 PMCID: PMC5156326 DOI: 10.1038/mp.2014.115] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 08/19/2014] [Accepted: 08/21/2014] [Indexed: 01/28/2023]
Abstract
Numerous investigations support decreased glutamatergic signaling as a pathogenic mechanism of schizophrenia, yet the molecular underpinnings for such dysregulation are largely unknown. In the post-mortem dorsolateral prefrontal cortex (DLPFC), we found striking decreases in tyrosine phosphorylation of N-methyl-D aspartate (NMDA) receptor subunit 2 (GluN2) that is critical for neuroplasticity. The decreased GluN2 activity in schizophrenia may not be because of downregulation of NMDA receptors as MK-801 binding and NMDA receptor complexes in postsynaptic density (PSD) were in fact increased in schizophrenia cases. At the postreceptor level, however, we found striking reductions in the protein kinase C, Pyk 2 and Src kinase activity that in tandem can decrease GluN2 activation. Given that Src serves as a hub of various signaling mechanisms affecting GluN2 phosphorylation, we postulated that Src hypoactivity may result from convergent alterations of various schizophrenia susceptibility pathways and thus mediate their effects on NMDA receptor signaling. Indeed, the DLPFC of schizophrenia cases exhibit increased PSD-95 and erbB4 and decreased receptor-type tyrosine-protein phosphatase-α (RPTPα) and dysbindin-1, each of which reduces Src activity via protein interaction with Src. To test genomic underpinnings for Src hypoactivity, we examined genome-wide association study results, incorporating 13 394 cases and 34 676 controls. We found no significant association of individual variants of Src and its direct regulators with schizophrenia. However, a protein-protein interaction-based network centered on Src showed significant enrichment of gene-level associations with schizophrenia compared with other psychiatric illnesses. Our results together demonstrate striking decreases in NMDA receptor signaling at the postreceptor level and propose Src as a nodal point of convergent dysregulations affecting NMDA receptor pathway via protein-protein associations.
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Affiliation(s)
- Anamika Banerjee
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Hoau-Yan Wang
- Department of Physiology, Pharmacology and Neuroscience, City University of New York Medical School, New York, NY 10031
| | | | - Mathew L. MacDonald
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Hagop Kaprielian
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Andres Stucky
- Department of Physiology, Pharmacology and Neuroscience, City University of New York Medical School, New York, NY 10031
| | - Jessica Kvasic
- Department of Physiology, Pharmacology and Neuroscience, City University of New York Medical School, New York, NY 10031
| | - Chijioke Egbujo
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Rabindranath Ray
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Konrad Talbot
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Scott E Hemby
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27106
| | - Steven J. Siegel
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Steven E. Arnold
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Patrick Sleiman
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
| | - Xiao Chang
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
| | - Hakon Hakonarson
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
| | - Raquel E. Gur
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Chang-Gyu Hahn
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
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14
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Phosphoinositide dynamics in the postsynaptic membrane compartment: Mechanisms and experimental approach. Eur J Cell Biol 2015; 94:401-14. [DOI: 10.1016/j.ejcb.2015.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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15
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Kanaani J, Cianciaruso C, Phelps EA, Pasquier M, Brioudes E, Billestrup N, Baekkeskov S. Compartmentalization of GABA synthesis by GAD67 differs between pancreatic beta cells and neurons. PLoS One 2015; 10:e0117130. [PMID: 25647668 PMCID: PMC4315522 DOI: 10.1371/journal.pone.0117130] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 12/19/2014] [Indexed: 11/22/2022] Open
Abstract
The inhibitory neurotransmitter GABA is synthesized by the enzyme glutamic acid decarboxylase (GAD) in neurons and in pancreatic β-cells in islets of Langerhans where it functions as a paracrine and autocrine signaling molecule regulating the function of islet endocrine cells. The localization of the two non-allelic isoforms GAD65 and GAD67 to vesicular membranes is important for rapid delivery and accumulation of GABA for regulated secretion. While the membrane anchoring and trafficking of GAD65 are mediated by intrinsic hydrophobic modifications, GAD67 remains hydrophilic, and yet is targeted to vesicular membrane pathways and synaptic clusters in neurons by both a GAD65-dependent and a distinct GAD65-independent mechanism. Herein we have investigated the membrane association and targeting of GAD67 and GAD65 in monolayer cultures of primary rat, human, and mouse islets and in insulinoma cells. GAD65 is primarily detected in Golgi membranes and in peripheral vesicles distinct from insulin vesicles in β-cells. In the absence of GAD65, GAD67 is in contrast primarily cytosolic in β-cells; its co-expression with GAD65 is necessary for targeting to Golgi membranes and vesicular compartments. Thus, the GAD65-independent mechanism for targeting of GAD67 to synaptic vesicles in neurons is not functional in islet β-cells. Therefore, only GAD65:GAD65 homodimers and GAD67:GAD65 heterodimers, but not the GAD67:GAD67 homodimer gain access to vesicular compartments in β-cells to facilitate rapid accumulation of newly synthesized GABA for regulated secretion and fine tuning of GABA-signaling in islets of Langerhans.
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Affiliation(s)
- Jamil Kanaani
- Departments of Medicine and Microbiology/Immunology, Diabetes Center, University of California San Francisco, San Francisco, California, United States of America
| | - Chiara Cianciaruso
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Edward A. Phelps
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Miriella Pasquier
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Estelle Brioudes
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Nils Billestrup
- Institute of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Steinunn Baekkeskov
- Departments of Medicine and Microbiology/Immunology, Diabetes Center, University of California San Francisco, San Francisco, California, United States of America
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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16
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Ménard C, Gaudreau P, Quirion R. Signaling pathways relevant to cognition-enhancing drug targets. Handb Exp Pharmacol 2015; 228:59-98. [PMID: 25977080 DOI: 10.1007/978-3-319-16522-6_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aging is generally associated with a certain cognitive decline. However, individual differences exist. While age-related memory deficits can be observed in humans and rodents in the absence of pathological conditions, some individuals maintain intact cognitive functions up to an advanced age. The mechanisms underlying learning and memory processes involve the recruitment of multiple signaling pathways and gene expression, leading to adaptative neuronal plasticity and long-lasting changes in brain circuitry. This chapter summarizes the current understanding of how these signaling cascades could be modulated by cognition-enhancing agents favoring memory formation and successful aging. It focuses on data obtained in rodents, particularly in the rat as it is the most common animal model studied in this field. First, we will discuss the role of the excitatory neurotransmitter glutamate and its receptors, downstream signaling effectors [e.g., calcium/calmodulin-dependent protein kinase II (CaMKII), protein kinase C (PKC), extracellular signal-regulated kinases (ERK), mammalian target of rapamycin (mTOR), cAMP response element-binding protein (CREB)], associated immediate early gene (e.g., Homer 1a, Arc and Zif268), and growth factors [insulin-like growth factors (IGFs) and brain-derived neurotrophic factor (BDNF)] in synaptic plasticity and memory formation. Second, the impact of the cholinergic system and related modulators on memory will be briefly reviewed. Finally, since dynorphin neuropeptides have recently been associated with memory impairments in aging, it is proposed as an attractive target to develop novel cognition-enhancing agents.
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Affiliation(s)
- Caroline Ménard
- Douglas Mental Health University Institute, McGill University, Perry Pavilion, 6875 LaSalle Boulevard, Montreal, QC, Canada, H4H 1R3
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17
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Maltecca F, Baseggio E, Consolato F, Mazza D, Podini P, Young SM, Drago I, Bahr BA, Puliti A, Codazzi F, Quattrini A, Casari G. Purkinje neuron Ca2+ influx reduction rescues ataxia in SCA28 model. J Clin Invest 2014; 125:263-74. [PMID: 25485680 DOI: 10.1172/jci74770] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 11/06/2014] [Indexed: 12/11/2022] Open
Abstract
Spinocerebellar ataxia type 28 (SCA28) is a neurodegenerative disease caused by mutations of the mitochondrial protease AFG3L2. The SCA28 mouse model, which is haploinsufficient for Afg3l2, exhibits a progressive decline in motor function and displays dark degeneration of Purkinje cells (PC-DCD) of mitochondrial origin. Here, we determined that mitochondria in cultured Afg3l2-deficient PCs ineffectively buffer evoked Ca²⁺ peaks, resulting in enhanced cytoplasmic Ca²⁺ concentrations, which subsequently triggers PC-DCD. This Ca²⁺-handling defect is the result of negative synergism between mitochondrial depolarization and altered organelle trafficking to PC dendrites in Afg3l2-mutant cells. In SCA28 mice, partial genetic silencing of the metabotropic glutamate receptor mGluR1 decreased Ca²⁺ influx in PCs and reversed the ataxic phenotype. Moreover, administration of the β-lactam antibiotic ceftriaxone, which promotes synaptic glutamate clearance, thereby reducing Ca²⁺ influx, improved ataxia-associated phenotypes in SCA28 mice when given either prior to or after symptom onset. Together, the results of this study indicate that ineffective mitochondrial Ca²⁺ handling in PCs underlies SCA28 pathogenesis and suggest that strategies that lower glutamate stimulation of PCs should be further explored as a potential treatment for SCA28 patients.
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18
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Maccarinelli F, Pagani A, Cozzi A, Codazzi F, Di Giacomo G, Capoccia S, Rapino S, Finazzi D, Politi LS, Cirulli F, Giorgio M, Cremona O, Grohovaz F, Levi S. A novel neuroferritinopathy mouse model (FTL 498InsTC) shows progressive brain iron dysregulation, morphological signs of early neurodegeneration and motor coordination deficits. Neurobiol Dis 2014; 81:119-33. [PMID: 25447222 PMCID: PMC4642750 DOI: 10.1016/j.nbd.2014.10.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/01/2014] [Accepted: 10/29/2014] [Indexed: 02/05/2023] Open
Abstract
Neuroferritinopathy is a rare genetic disease with a dominant autosomal transmission caused by mutations of the ferritin light chain gene (FTL). It belongs to Neurodegeneration with Brain Iron Accumulation, a group of disorders where iron dysregulation is tightly associated with neurodegeneration. We studied the 498–499InsTC mutation which causes the substitution of the last 9 amino acids and an elongation of extra 16 amino acids at the C-terminus of L-ferritin peptide. An analysis with cyclic voltammetry on the purified protein showed that this structural modification severely reduces the ability of the protein to store iron. In order to analyze the impact of the mutation in vivo, we generated mouse models for the some pathogenic human FTL gene in FVB and C57BL/6J strains. Transgenic mice in the FVB background showed high accumulation of the mutated ferritin in brain where it correlated with increased iron deposition with age, as scored by magnetic resonance imaging. Notably, the accumulation of iron–ferritin bodies was accompanied by signs of oxidative damage. In the C57BL/6 background, both the expression of the mutant ferritin and the iron levels were lower than in the FVB strain. Nevertheless, also these mice showed oxidative alterations in the brain. Furthermore, post-natal hippocampal neurons obtained from these mice experienced a marked increased cell death in response to chronic iron overload and/or acute oxidative stress, in comparison to wild-type neurons. Ultrastructural analyses revealed an accumulation of lipofuscin granules associated with iron deposits, particularly enriched in the cerebellum and striatum of our transgenic mice. Finally, experimental subjects were tested throughout development and aging at 2-, 8- and 18-months for behavioral phenotype. Rotarod test revealed a progressive impaired motor coordination building up with age, FTL mutant old mice showing a shorter latency to fall from the apparatus, according to higher accumulation of iron aggregates in the striatum. Our data show that our 498–499InsTC mouse models recapitulate early pathological and clinical traits of the human neuroferritinopathy, thus providing a valuable model for the study of the disease. Finally, we propose a mechanistic model of lipofuscine formation that can account for the etiopathogenesis of human neuroferritinopathy. We developed two new neuroferritinopathy mice models (NF). NF brains are characterized by iron/ferritin accumulation and oxidative damage. NF brains show granules of lipofuscine associated with iron. A mechanism of lipofuscine formation is proposed. NF mice show impaired motor coordination increasing with age.
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Affiliation(s)
| | - Antonella Pagani
- San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy
| | - Anna Cozzi
- San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy; Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano, Italy
| | - Franca Codazzi
- San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy
| | | | - Sara Capoccia
- Section of Behavioral Neuroscience, Department of Cell Biology, Istituto Superiore di Sanità, Rome, Italy
| | - Stefania Rapino
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Dario Finazzi
- Department of Molecular and Translational Medicine, University of Brescia, Italy
| | | | - Francesca Cirulli
- Section of Behavioral Neuroscience, Department of Cell Biology, Istituto Superiore di Sanità, Rome, Italy
| | - Marco Giorgio
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Ottavio Cremona
- San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy; Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano, Italy
| | - Fabio Grohovaz
- San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy; Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano, Italy.
| | - Sonia Levi
- San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy; Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano, Italy.
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19
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Youn DH. Differential roles of signal transduction mechanisms in long-term potentiation of excitatory synaptic transmission induced by activation of group I mGluRs in the spinal trigeminal subnucleus oralis. Brain Res Bull 2014; 108:37-43. [PMID: 25149878 DOI: 10.1016/j.brainresbull.2014.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 08/11/2014] [Indexed: 12/13/2022]
Abstract
Group I metabotropic glutamate receptors (mGluR1 and 5) have been implicated in long-term potentiation (LTP), a persistent increase of synaptic efficiency, in the central nervous system including the spinal trigeminal nucleus (Vsp). In the ascending pathway from the caudalis (Vc) to the oralis (Vo) subnuclus in Vsp, it has been shown that the activation of group I mGluRs (mGluR1 and 5) with their agonist (S)-3,5-dihydroxyphenylglycine (DHPG) produces a delayed type of LTP of excitatory synaptic transmission and this LTP was mediated by mGluR1. Further, this study attempts to pharmacologically characterize essential signaling components for the expression of DHPG-induced LTP. As a result, it is found that the group I mGluRs essentially use G protein-mediated activation of the phospholipase C (PLC) pathway to express the LTP. However, recruited signaling molecules following the activation of PLC are differentially involved in the expression of LTP: i.e. IP3 receptor, intracellular Ca(2+) rise, CaMKII and ERK function as positive regulators, whereas PKC as a negative regulator. Furthermore, both L-type voltage-dependent Ca(2+) channel and canonical transient receptor potential channel positively contribute to the expression of LTP. Taken together, these results suggest that signaling molecules recruited by the activation of group I mGluRs collaboratively or oppositely control the optimal expression of synaptic plasticity at excitatory synapses in the Vo.
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Affiliation(s)
- Dong-ho Youn
- Department of Oral Physiology, School of Dentistry, Kyungpook National University, 2177 Dalgubeol Blvd., Jung-gu, Daegu 700-706, Republic of Korea.
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M1-muscarinic receptors promote fear memory consolidation via phospholipase C and the M-current. J Neurosci 2014; 34:1570-8. [PMID: 24478341 DOI: 10.1523/jneurosci.1040-13.2014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Neuromodulators released during and after a fearful experience promote the consolidation of long-term memory for that experience. Because overconsolidation may contribute to the recurrent and intrusive memories of post-traumatic stress disorder, neuromodulatory receptors provide a potential pharmacological target for prevention. Stimulation of muscarinic receptors promotes memory consolidation in several conditioning paradigms, an effect primarily associated with the M1 receptor (M1R). However, neither inhibiting nor genetically disrupting M1R impairs the consolidation of cued fear memory. Using the M1R agonist cevimeline and antagonist telenzepine, as well as M1R knock-out mice, we show here that M1R, along with β2-adrenergic (β2AR) and D5-dopaminergic (D5R) receptors, regulates the consolidation of cued fear memory by redundantly activating phospholipase C (PLC) in the basolateral amygdala (BLA). We also demonstrate that fear memory consolidation in the BLA is mediated in part by neuromodulatory inhibition of the M-current, which is conducted by KCNQ channels and is known to be inhibited by muscarinic receptors. Manipulating the M-current by administering the KCNQ channel blocker XE991 or the KCNQ channel opener retigabine reverses the effects on consolidation caused by manipulating β2AR, D5R, M1R, and PLC. Finally, we show that cAMP and protein kinase A (cAMP/PKA) signaling relevant to this stage of consolidation is upstream of these neuromodulators and PLC, suggesting an important presynaptic role for cAMP/PKA in consolidation. These results support the idea that neuromodulatory regulation of ion channel activity and neuronal excitability is a critical mechanism for promoting consolidation well after acquisition has occurred.
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21
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Menard C, Bastianetto S, Quirion R. Neuroprotective effects of resveratrol and epigallocatechin gallate polyphenols are mediated by the activation of protein kinase C gamma. Front Cell Neurosci 2013; 7:281. [PMID: 24421757 PMCID: PMC3872731 DOI: 10.3389/fncel.2013.00281] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/15/2013] [Indexed: 01/08/2023] Open
Abstract
Polyphenols such as epigallocatechin gallate (EGCG) and resveratrol have received a great deal of attention because they may contribute to the purported neuroprotective action of the regular consumption of green tea and red wine. Many studies, including those published by our group, suggest that this protective action includes their abilities to prevent the neurotoxic effects of beta-amyloid, a protein whose accumulation likely plays a pivotal role in Alzheimer's disease. Moreover, the scavenging activities of polyphenols on reactive oxygen species and their inhibitory action of cyclooxygenase likely explain, at least in part, their antioxidant and anti-inflammatory activities. Besides these well-documented properties, the modulatory action of these polyphenols on intracellular signaling pathways related to cell death/survival (e.g., protein kinase C, PKC) has yet to be investigated in detail. Using rat hippocampal neuronal cells, we aimed to investigate here the effects of EGCG and resveratrol on cell death induced by GF 109203X, a selective inhibitor of PKC. The MTT/resazurin and spectrin assays indicated that EGCG and resveratrol protected against GF 109203X-induced cell death and cytoskeleton degeneration, with a maximal effect at 1 and 3 μM, respectively. Moreover, immunofluorescence data revealed that cells treated with these polyphenols increased PKC gamma (γ) activation and promoted neuronal interconnections. Finally, we found that the protective effects of both polyphenols on the cytoskeleton and synaptic plasticity were mediated by the PKCγ subunit. Taken together, the results suggest that PKC, and more specifically its γ subunit, plays a critical role in the protective action of EGCG and resveratrol on neuronal integrity.
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Affiliation(s)
- Caroline Menard
- Laboratory of Neuroendocrinology of Aging, Centre Hospitalier de l'Université de Montréal Research Center Montreal, QC, Canada ; Department of Medicine, University of Montreal Montreal, QC, Canada ; Douglas Mental Health University Institute, McGill University Montreal, QC, Canada ; Department of Psychiatry, McGill University Montreal, QC, Canada
| | - Stéphane Bastianetto
- Douglas Mental Health University Institute, McGill University Montreal, QC, Canada
| | - Rémi Quirion
- Douglas Mental Health University Institute, McGill University Montreal, QC, Canada ; Department of Psychiatry, McGill University Montreal, QC, Canada
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22
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Hashimotodani Y, Ohno-Shosaku T, Tanimura A, Kita Y, Sano Y, Shimizu T, Di Marzo V, Kano M. Acute inhibition of diacylglycerol lipase blocks endocannabinoid-mediated retrograde signalling: evidence for on-demand biosynthesis of 2-arachidonoylglycerol. J Physiol 2013; 591:4765-76. [PMID: 23858009 DOI: 10.1113/jphysiol.2013.254474] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The endocannabinoid (eCB) 2-arachidonoylglycerol (2-AG) produced by diacylglycerol lipase α (DGLα) is one of the best-characterized retrograde messengers at central synapses. It has been thought that 2-AG is produced 'on demand' upon activation of postsynaptic neurons. However, recent studies propose that 2-AG is pre-synthesized by DGLα and stored in neurons, and that 2-AG is released from such 'pre-formed pools' without the participation of DGLα. To address whether the 2-AG source for retrograde signalling is the on-demand biosynthesis by DGLα or the mobilization from pre-formed pools, we examined the effects of acute pharmacological inhibition of DGL by a novel potent DGL inhibitor, OMDM-188, on retrograde eCB signalling triggered by Ca(2+) elevation, Gq/11 protein-coupled receptor activation or synergy of these two stimuli in postsynaptic neurons. We found that pretreatment for 1 h with OMDM-188 effectively blocked depolarization-induced suppression of inhibition (DSI), a purely Ca(2+)-dependent form of eCB signalling, in slices from the hippocampus, striatum and cerebellum. We also found that at parallel fibre-Purkinje cell synapses in the cerebellum OMDM-188 abolished synaptically induced retrograde eCB signalling, which is known to be caused by the synergy of postsynaptic Ca(2+) elevation and group I metabotropic glutamate receptor (I-mGluR) activation. Moreover, brief OMDM-188 treatments for several minutes were sufficient to suppress both DSI and the I-mGluR-induced retrograde eCB signalling in cultured hippocampal neurons. These results are consistent with the hypothesis that 2-AG for synaptic retrograde signalling is supplied as a result of on-demand biosynthesis by DGLα rather than mobilization from presumptive pre-formed pools.
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Affiliation(s)
- Yuki Hashimotodani
- M. Kano: Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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23
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Pelizzoni I, Zacchetti D, Campanella A, Grohovaz F, Codazzi F. Iron uptake in quiescent and inflammation-activated astrocytes: a potentially neuroprotective control of iron burden. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1326-33. [PMID: 23583428 PMCID: PMC3787737 DOI: 10.1016/j.bbadis.2013.04.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 03/28/2013] [Accepted: 04/03/2013] [Indexed: 02/03/2023]
Abstract
Astrocytes play a crucial role in proper iron handling within the central nervous system. This competence can be fundamental, particularly during neuroinflammation, and neurodegenerative processes, where an increase in iron content can favor oxidative stress, thereby worsening disease progression. Under these pathological conditions, astrocytes undergo a process of activation that confers them either a beneficial or a detrimental role on neuronal survival. Our work investigates the mechanisms of iron entry in cultures of quiescent and activated hippocampal astrocytes. Our data confirm that the main source of iron is the non-transferrin-bound iron (NTBI) and show the involvement of two different routes for its entry: the resident transient receptor potential (TRP) channels in quiescent astrocytes and the de novo expressed divalent metal transporter 1 (DMT1) in activated astrocytes, which accounts for a potentiation of iron entry. Overall, our data suggest that at rest, but even more after activation, astrocytes have the potential to buffer the excess of iron, thereby protecting neurons from iron overload. These findings further extend our understanding of the protective role of astrocytes under the conditions of iron-mediated oxidative stress observed in several neurodegenerative conditions. Non-transferrin-bound iron (NTBI) is the main source of iron for astrocytes. TRPC channels represent an entry pathway for Fe2 + in resting astrocytes. Activation process increases the competence of astrocytes to uptake iron. DMT1 expression accounts for potentiation of iron ingress in activated astrocytes.
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Affiliation(s)
- Ilaria Pelizzoni
- San Raffaele Scientific Institute, via Olgettina 60, 20132 Milano, Italy
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24
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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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25
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Farah CA, Sossin WS. The role of C2 domains in PKC signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:663-83. [PMID: 22453964 DOI: 10.1007/978-94-007-2888-2_29] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
More than two decades ago, the discovery of the first C2 domain in conventional Protein Kinase Cs (cPKCs) and of its role as a calcium-binding motif began to shed light on the activation mechanism of this family of Serine/Threonine kinases which are involved in several critical signal transduction pathways. In this chapter, we review the current knowledge of the structure and the function of the different C2 domains in PKCs. The C2 domain of cPKCs is a calcium sensor and its calcium-dependent binding to phospholipids is crucial for kinase activation. While the functional role of the cPKC C2 domain is better understood, phylogenetic analysis revealed that the novel C2 domain is more ancient and related to the C2 domain in the fungal PKC family, while the cPKC C2 domain is first associated with PKC in metazoans. The C2 domain of novel PKCs (nPKCs) does not contain a calcium-binding motif but still plays a critical role in nPKCs activation by regulating C1-C2 domain interactions and consequently C2 domain-mediated inhibition in both the nPKCs of the epsilon family and the nPKCs of the delta family. Moreover, the C2 domain of the nPKCs of the delta family was shown to recognize phosphotyrosines in a novel mode different from the ones observed for the Src Homology 2 (SH2) and the phosphotyrosine binding domains (PTB). By binding to phosphotyrosines, the C2 domain regulates the activation of this subclass of PKCs. The C2 domain was also shown to be involved in protein-protein interactions and binding to the receptor for activated C-kinase (RACKs) thus contributing to the subcellular localization of PKCs. In summary, the C2 domain is a critical player that can sense the activated signaling pathway in response to external stimuli to specifically regulate the different conventional and novel PKC isoforms.
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Affiliation(s)
- Carole A Farah
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, BT 105, 3801 University Street, Montreal, QC H3A 2B4, Canada.
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26
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Kim H, Han SH, Quan HY, Jung YJ, An J, Kang P, Park JB, Yoon BJ, Seol GH, Min SS. Bryostatin-1 promotes long-term potentiation via activation of PKCα and PKCε in the hippocampus. Neuroscience 2012; 226:348-55. [PMID: 22986161 DOI: 10.1016/j.neuroscience.2012.08.055] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 08/24/2012] [Accepted: 08/27/2012] [Indexed: 11/16/2022]
Abstract
Activation of protein kinase C (PKC) by bryostatin-1 affects various functions of the central nervous system. We explored whether bryostatin-1 influenced synaptic plasticity via a process involving PKC. Our purpose was to examine whether bryostatin-1 affected the induction of hippocampal long-term potentiation (LTP) in Schaffer-collateral fibers (CA1 fibers) of the hippocampus, and/or influenced the intracellular Ca(2+) level of hippocampal neurons. We also determined the PKC isoforms involved in these processes. We found that bryostatin-1 strongly facilitated LTP induction, in a dose-dependent manner, upon single-theta burst stimulation (TBS). Further, intracellular Ca(2+) levels also increased with increasing concentration of bryostatin-1. The facilitative effects of bryostatin-1 in terms of LTP induction and enhancement of intracellular Ca(2+) levels were blocked by specific inhibitors of PKCα and PKCε, but not of PKCδ. Our results suggest that bryostatin-1 is involved in neuronal functioning and facilitates induction of LTP via activation of PKCα and/or PKCε.
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Affiliation(s)
- H Kim
- Department of Physiology and Biophysics, School of Medicine, Eulji University, Daejeon 301-746, Republic of Korea
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27
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NMDA receptor-dependent synaptic activation of TRPC channels in olfactory bulb granule cells. J Neurosci 2012; 32:5737-46. [PMID: 22539836 DOI: 10.1523/jneurosci.3753-11.2012] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Canonical transient receptor potential (TRPC) channels are widely expressed throughout the nervous system including the olfactory bulb where their function is largely unknown. Here, we describe their contribution to central synaptic processing at the reciprocal mitral and tufted cell-granule cell microcircuit, the most abundant synapse of the mammalian olfactory bulb. Suprathreshold activation of the synapse causes sodium action potentials in mouse granule cells and a subsequent long-lasting depolarization (LLD) linked to a global dendritic postsynaptic calcium signal recorded with two-photon laser-scanning microscopy. These signals are not observed after action potentials evoked by current injection in the same cells. The LLD persists in the presence of group I metabotropic glutamate receptor antagonists but is entirely absent from granule cells deficient for the NMDA receptor subunit NR1. Moreover, both depolarization and Ca²⁺ rise are sensitive to the blockade of NMDA receptors. The LLD and the accompanying Ca²⁺ rise are also absent in granule cells from mice deficient for both TRPC channel subtypes 1 and 4, whereas the deletion of either TRPC1 or TRPC4 results in only a partial reduction of the LLD. Recordings from mitral cells in the absence of both subunits reveal a reduction of asynchronous neurotransmitter release from the granule cells during recurrent inhibition. We conclude that TRPC1 and TRPC4 can be activated downstream of NMDA receptor activation and contribute to slow synaptic transmission in the olfactory bulb, including the calcium dynamics required for asynchronous release from the granule cell spine.
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28
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Huang YN, Tsai RY, Lin SL, Chien CC, Cherng CH, Wu CT, Yeh CC, Wong CS. Amitriptyline attenuates astrocyte activation and morphine tolerance in rats: Role of the PSD-95/NR1/nNOS/PKCγ signaling pathway. Behav Brain Res 2012; 229:401-11. [DOI: 10.1016/j.bbr.2012.01.044] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 01/19/2012] [Accepted: 01/23/2012] [Indexed: 12/13/2022]
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Ceruloplasmin oxidation, a feature of Parkinson's disease CSF, inhibits ferroxidase activity and promotes cellular iron retention. J Neurosci 2012; 31:18568-77. [PMID: 22171055 DOI: 10.1523/jneurosci.3768-11.2011] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Parkinson's disease is a neurodegenerative disorder characterized by oxidative stress and CNS iron deposition. Ceruloplasmin is an extracellular ferroxidase that regulates cellular iron loading and export, and hence protects tissues from oxidative damage. Using two-dimensional electrophoresis, we investigated ceruloplasmin patterns in the CSF of human Parkinson's disease patients. Parkinson's disease ceruloplasmin profiles proved more acidic than those found in healthy controls and in other human neurological diseases (peripheral neuropathies, amyotrophic lateral sclerosis, and Alzheimer's disease); degrees of acidity correlated with patients' pathological grading. Applying an unsupervised pattern recognition procedure to the two-dimensional electrophoresis images, we identified representative pathological clusters. In vitro oxidation of CSF in two-dimensional electrophoresis generated a ceruloplasmin shift resembling that observed in Parkinson's disease and co-occurred with an increase in protein carbonylation. Likewise, increased protein carbonylation was observed in Parkinson's disease CSF, and the same modification was directly identified in these samples on ceruloplasmin. These results indicate that ceruloplasmin oxidation contributes to pattern modification in Parkinson's disease. From the functional point of view, ceruloplasmin oxidation caused a decrease in ferroxidase activity, which in turn promotes intracellular iron retention in neuronal cell lines as well as in primary neurons, which are more sensitive to iron accumulation. Accordingly, the presence of oxidized ceruloplasmin in Parkinson's disease CSF might be used as a marker for oxidative damage and might provide new insights into the underlying pathological mechanisms.
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Abstract
Synaptic transmission is amongst the most sophisticated and tightly controlled biological phenomena in higher eukaryotes. In the past few decades, tremendous progress has been made in our understanding of the molecular mechanisms underlying multiple facets of neurotransmission, both pre- and postsynaptically. Brought under the spotlight by pioneer studies in the areas of secretion and signal transduction, phosphoinositides and their metabolizing enzymes have been increasingly recognized as key protagonists in fundamental aspects of neurotransmission. Not surprisingly, dysregulation of phosphoinositide metabolism has also been implicated in synaptic malfunction associated with a variety of brain disorders. In the present chapter, we summarize current knowledge on the role of phosphoinositides at the neuronal synapse and highlight some of the outstanding questions in this research field.
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Affiliation(s)
- Samuel G Frere
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, 630 West 168th Street, P&S 12-420C, 10032, New York, USA
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31
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Pelizzoni I, Zacchetti D, Smith CP, Grohovaz F, Codazzi F. Expression of divalent metal transporter 1 in primary hippocampal neurons: reconsidering its role in non-transferrin-bound iron influx. J Neurochem 2012; 120:269-78. [PMID: 22121954 DOI: 10.1111/j.1471-4159.2011.07578.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The divalent metal transporter 1 (DMT1) is the best characterized Fe²⁺ transporter involved in cellular iron uptake in mammals. Four possible isoforms have been identified as a result of alternative promoter (DMT1-1A and DMT1-1B) and alternative splicing involving the C-terminus and producing transcripts with or without an iron responsive element [DMT1-IRE⁺ and DMT1-IRE⁻, respectively]. Despite the general importance of DMT1 in controlling iron homeostasis, the distribution and the role of the transporter in the CNS is still controversial. In this study, we characterize the expression of DMT1 in hippocampal neurons and astrocytes. We found that the main isoform endogenously expressed is DMT1-1B/IRE⁺, which shows cytoplasmic distribution, colocalization with late endosome/lysosome markers and iron regulation, as expected from the presence of an iron responsive element. Our results also show that DMT1-1B/IRE⁺ isoform does not sustain iron entry, even after its neuronal over-expression. Overall, our results argue against a physiological role of the endogenous DMT1 in neuronal iron uptake but do not exclude that, under pathological conditions, the expression of other DMT1 isoforms might contribute to iron overload.
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Affiliation(s)
- Ilaria Pelizzoni
- San Raffaele Scientific Institute, Division of Neuroscience, Milano, Italy
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32
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Shaping up the membrane: diacylglycerol coordinates spatial orientation of signaling. Trends Biochem Sci 2011; 36:593-603. [PMID: 21798744 DOI: 10.1016/j.tibs.2011.06.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Revised: 06/21/2011] [Accepted: 06/23/2011] [Indexed: 11/23/2022]
Abstract
Diacylglycerol signals by binding and activating C1 domain-containing proteins expressed principally in neuronal and immune tissues. This restricted expression profile suggests that diacylglycerol-regulated signals are particularly relevant in cell-cell communication processes in which active endocytosis and exocytosis take place. Not surprisingly, various experimental approaches have demonstrated a crucial role for diacylglycerol effectors and metabolizing enzymes in the control of immune responses, neuron communication and phagocytosis. Current research delineates a scenario in which coordinated decoding of diacylglycerol signals is translated into complex biological responses such as neuronal plasticity, T cell development or cytolytic killing. Diacylglycerol functions reach maximal diversity in these highly specialized systems in which signal intensity directly regulates distinct biological outcomes. This review brings together the most recent studies, emphasizing the contribution of compartmentalized DAG metabolism to orientated signaling events.
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33
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Pelizzoni I, Macco R, Morini MF, Zacchetti D, Grohovaz F, Codazzi F. Iron handling in hippocampal neurons: activity-dependent iron entry and mitochondria-mediated neurotoxicity. Aging Cell 2011; 10:172-83. [PMID: 21108725 DOI: 10.1111/j.1474-9726.2010.00652.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The characterization of iron handling in neurons is still lacking, with contradictory and incomplete results. In particular, the relevance of non-transferrin-bound iron (NTBI), under physiologic conditions, during aging and in neurodegenerative disorders, is undetermined. This study investigates the mechanisms underlying NTBI entry into primary hippocampal neurons and evaluates the consequence of iron elevation on neuronal viability. Fluorescence-based single cell analysis revealed that an increase in extracellular free Fe(2+) (the main component of NTBI pool) is sufficient to promote Fe(2+) entry and that activation of either N-methyl-d-aspartate receptors (NMDARs) or voltage operated calcium channels (VOCCs) significantly potentiates this pathway, independently of changes in intracellular Ca(2+) concentration ([Ca(2+) ](i) ). The enhancement of Fe(2+) influx was accompanied by a corresponding elevation of reactive oxygen species (ROS) production and higher susceptibility of neurons to death. Interestingly, iron vulnerability increased in aged cultures. Scavenging of mitochondrial ROS was the most powerful protective treatment against iron overload, being able to preserve the mitochondrial membrane potential and to safeguard the morphologic integrity of these organelles. Overall, we demonstrate for the first time that Fe(2+) and Ca(2+) compete for common routes (i.e. NMDARs and different types of VOCCs) to enter primary neurons. These iron entry pathways are not controlled by the intracellular iron level and can be harmful for neurons during aging and in conditions of elevated NTBI levels. Finally, our data draw the attention to mitochondria as a potential target for the treatment of the neurodegenerative processes induced by iron dysmetabolism.
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Affiliation(s)
- Ilaria Pelizzoni
- Cellular Neurophysiology Unit, Division of Neuroscience, San Raffaele Scientific Institute, via Olgettina 58, I-20132 Milano, Italy
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Murotomi K, Takagi N, Mizutani R, Honda TA, Ono M, Takeo S, Tanonaka K. mGluR1 antagonist decreased NADPH oxidase activity and superoxide production after transient focal cerebral ischemia. J Neurochem 2010; 114:1711-9. [PMID: 20598019 DOI: 10.1111/j.1471-4159.2010.06882.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
NADPH oxidase, which is activated by PKC and signaling via the NMDA receptor, is one of the crucial enzymes for superoxide production in the CNS. We showed earlier that the metabotropic glutamate receptor 1 (mGluR1) plays an important role in the activation of PKC and tyrosine phosphorylation of the NMDA receptor, which has been implicated in enhancement of the channel activity, after cerebral ischemia. In this study, we sought to determine the role of mGluR1 in the activation of NADPH oxidase and subsequent superoxide production after transient focal cerebral ischemia. The amounts of NADPH oxidase subunits in the membrane fraction were increased after the start of reperfusion. These changes were accompanied by increased NADPH oxidase activity followed by superoxide production. The administration of an mGluR1 antagonist attenuated NADPH oxidase activity, which was coincident with inhibition of superoxide production. We further showed that the increase in the amount of PKCδ, but not of PKCζ, as well as the increase in those of NADPH oxidase subunits, was attenuated by the mGluR1 antagonist. These results suggest that mGluR1 may be linked to the increase in NADPH oxidase activity that is mediated by PKCδ and subsequent superoxide production after cerebral ischemia.
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Affiliation(s)
- Kazutoshi Murotomi
- Department of Molecular and Cellular Pharmacology, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
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35
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Fontanez-Nuin DE, Santini E, Quirk GJ, Porter JT. Memory for fear extinction requires mGluR5-mediated activation of infralimbic neurons. ACTA ACUST UNITED AC 2010; 21:727-35. [PMID: 20705895 DOI: 10.1093/cercor/bhq147] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Consolidation of fear extinction involves enhancement of N-methyl D aspartate (NMDA) receptor-dependent bursting in the infralimbic region (IL) of the medial prefrontal cortex (mPFC). Previous studies have shown that systemic blockade of metabotropic glutamate receptor type 5 (mGluR5) reduces bursting in the mPFC and mGluR5 agonists enhance NMDA receptor currents in vitro, suggesting that mGluR5 activation in IL may contribute to fear extinction. In the current study, rats injected with the mGluR5 antagonist 2-methyl-6-(phenylethyl)-pyridine (MPEP) systemically, or intra-IL, prior to extinction exhibited normal within-session extinction, but were impaired in their ability to recall extinction the following day. To directly determine whether mGluR5 stimulation enhances the burst firing of IL neurons, we used patch-clamp electrophysiology in prefrontal slices. The mGluR5 agonist, (RS)-2-chloro-5-hydroxyphenylglycine (CHPG), increased intrinsic bursting in IL neurons. Increased bursting was correlated with a reduction in the slow after hyperpolarizing potential and was prevented by coapplication of MPEP. CHPG did not increase NMDA currents, suggesting that an NMDA receptor-independent enhancement of IL bursting via stimulation of mGluR5 receptors contributes to fear extinction. Therefore, the mGluR5 receptor could be a suitable target for pharmacological adjuncts to extinction-based therapies for anxiety disorders.
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Affiliation(s)
- Darah E Fontanez-Nuin
- Department of Physiology and Pharmacology, Ponce School of Medicine, Ponce, Puerto Rico 00732-7004
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Involvement of the spinal NMDA receptor/PKCγ signaling pathway in the development of bone cancer pain. Brain Res 2010; 1335:83-90. [PMID: 20362561 DOI: 10.1016/j.brainres.2010.03.083] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2009] [Revised: 03/24/2010] [Accepted: 03/26/2010] [Indexed: 11/23/2022]
Abstract
N-methyl-d-aspartate (NMDA) receptor and protein kinase C (PKC) play important roles in the induction and maintenance of central sensitization during pain states. It has been shown that spinal NMDA receptor-dependent activation of PKCgamma facilitates nociception during neuropathic and inflammatory pain, but its involvement in bone cancer pain has not previously been established. The aim of this study was to examine the potential role of the spinal NMDA receptor/PKCgamma signaling pathway in the development of bone cancer pain. Osteosarcoma NCTC 2472 cells were implanted into the intramedullary space of the right femurs of C3H/HeJ mice to induce ongoing bone cancer-related pain behaviors. At day 7, 10 and 14 after operation, the expression of PKCgamma mRNA in the spinal cord was higher in tumor-bearing mice compared to the sham mice. At day 14, intrathecal administration of 5 microg of NR2B subunit-specific NMDA receptor antagonist ifenprodil attenuated the up-regulation of PKCgamma mRNA in the spinal cord as well as bone cancer-evoked thermal hyperalgesia and mechanical allodynia. Furthermore, intrathecal injection of 10 microg of PKC inhibitor H-7 attenuated cancer-evoked thermal hyperalgesia and mechanical allodynia at day 14. These results suggest that the NMDA receptor/PKCgamma signaling pathway may participate in the development of bone cancer pain, and ifenprodil may be a useful alternative or adjunct therapy for bone cancer pain.
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Bartos JA, Ulrich JD, Li H, Beazely MA, Chen Y, MacDonald JF, Hell JW. Postsynaptic clustering and activation of Pyk2 by PSD-95. J Neurosci 2010; 30:449-63. [PMID: 20071509 PMCID: PMC2822408 DOI: 10.1523/jneurosci.4992-08.2010] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2008] [Revised: 11/01/2009] [Accepted: 11/04/2009] [Indexed: 12/24/2022] Open
Abstract
The tyrosine kinase Pyk2 plays a unique role in intracellular signal transduction by linking Ca(2+) influx to tyrosine phosphorylation, but the molecular mechanism of Pyk2 activation is unknown. We report that Pyk2 oligomerization by antibodies in vitro or overexpression of PSD-95 in PC6-3 cells induces trans-autophosphorylation of Tyr402, the first step in Pyk2 activation. In neurons, Ca(2+) influx through NMDA-type glutamate receptors causes postsynaptic clustering and autophosphorylation of endogenous Pyk2 via Ca(2+)- and calmodulin-stimulated binding to PSD-95. Accordingly, Ca(2+) influx promotes oligomerization and thereby autoactivation of Pyk2 by stimulating its interaction with PSD-95. We show that this mechanism of Pyk2 activation is critical for long-term potentiation in the hippocampus CA1 region, which is thought to underlie learning and memory.
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Affiliation(s)
- Jason A. Bartos
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242-1109
| | - Jason D. Ulrich
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242-1109
| | - Hongbin Li
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada, and
| | - Michael A. Beazely
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada, and
| | - Yucui Chen
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242-1109
| | - John F. MacDonald
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada, and
- Robarts Research Institute, University of Western Ontario, London, Ontario N6A 5K8, Canada
| | - Johannes W. Hell
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242-1109
- Department of Pharmacology, University of California, Davis, Davis, California 95616-8636
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Sossin WS, Abrams TW. Evolutionary conservation of the signaling proteins upstream of cyclic AMP-dependent kinase and protein kinase C in gastropod mollusks. BRAIN, BEHAVIOR AND EVOLUTION 2009; 74:191-205. [PMID: 20029183 DOI: 10.1159/000258666] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The protein kinase C (PKC) and the cAMP-dependent kinase (protein kinase A; PKA) pathways are known to play important roles in behavioral plasticity and learning in the nervous systems of a wide variety of species across phyla. We briefly review the members of the PKC and PKA family and focus on the evolution of the immediate upstream activators of PKC and PKA i.e., phospholipase C (PLC) and adenylyl cyclase (AC), and their conservation in gastropod mollusks, taking advantage of the recent assembly of the Aplysiacalifornica and Lottia gigantea genomes. The diversity of PLC and AC family members present in mollusks suggests a multitude of possible mechanisms to activate PKA and PKC; we briefly discuss the relevance of these pathways to the known physiological activation of these kinases in Aplysia neurons during plasticity and learning. These multiple mechanisms of activation provide the gastropod nervous system with tremendous flexibility for implementing neuromodulatory responses to both neuronal activity and extracellular signals.
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Affiliation(s)
- Wayne S Sossin
- Department of Neurology and Neurosurgery, McGill University, Montreal Neurological Institute, Montreal, Que., Canada.
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NMDA-mediated and self-induced bdnf exon IV transcriptions are differentially regulated in cultured cortical neurons. Neurochem Int 2009; 54:385-92. [DOI: 10.1016/j.neuint.2009.01.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Shobe JL, Zhao Y, Stough S, Ye X, Hsuan V, Martin KC, Carew TJ. Temporal phases of activity-dependent plasticity and memory are mediated by compartmentalized routing of MAPK signaling in aplysia sensory neurons. Neuron 2009; 61:113-25. [PMID: 19146817 DOI: 10.1016/j.neuron.2008.10.049] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 09/12/2008] [Accepted: 10/29/2008] [Indexed: 11/25/2022]
Abstract
An activity-dependent form of intermediate memory (AD-ITM) for sensitization is induced in Aplysia by a single tail shock that gives rise to plastic changes (AD-ITF) in tail sensory neurons (SNs) via the interaction of action potential firing in the SN coupled with the release of serotonin in the CNS. Activity-dependent long-term facilitation (AD-LTF, lasting >24hr) requires protein synthesis dependent persistent mitogen-activated protein kinase (MAPK) activation and translocation to the SN nucleus. We now show that the induction of the earlier temporal phase (AD-ITM and AD-ITF), which is translation and transcription independent, requires the activation of a compartmentally distinct novel signaling cascade that links second messengers, MAPK and PKC into a unified pathway within tail SNs. Since both AD-ITM and AD-LTM require MAPK activity, these collective findings suggest that presynaptic SNs route the flow of molecular information to distinct subcellular compartments during the induction of activity-dependent long-lasting memories.
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Affiliation(s)
- Justin L Shobe
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA
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Iron and calcium in the central nervous system: a close relationship in health and sickness. Biochem Soc Trans 2009; 36:1309-12. [PMID: 19021546 DOI: 10.1042/bst0361309] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Iron and calcium are required for general cellular functions, as well as for specific neuronal-related activities. However, a pathological increase in their levels favours oxidative stress and mitochondrial damage, leading to neuronal death. Neurodegeneration can thus be determined by alterations in ionic homoeostasis and/or pro-oxidative-antioxidative equilibrium, two conditions that vary significantly in different kinds of brain cell and also with aging. In the present review, we re-evaluate recent data on NTBI (non-transferrin bound iron) uptake that suggest a strict interplay with the mechanisms of calcium control. In particular, we focus on the use of common entry pathways and on the way cytosolic calcium can modulate iron entry and determine its intracellular accumulation.
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43
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Horne EA, Stella N. The ins and outs of endocannabinoid signaling in healthy and diseased brain. ACTA ACUST UNITED AC 2008. [DOI: 10.2217/17460875.3.4.435] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Cheng HT, Suzuki M, Hegarty DM, Xu Q, Weyerbacher AR, South SM, Ohata M, Inturrisi CE. Inflammatory pain-induced signaling events following a conditional deletion of the N-methyl-D-aspartate receptor in spinal cord dorsal horn. Neuroscience 2008; 155:948-58. [PMID: 18621103 DOI: 10.1016/j.neuroscience.2008.06.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 05/23/2008] [Accepted: 06/10/2008] [Indexed: 12/24/2022]
Abstract
The N-methyl-d-aspartate (NMDA) receptor in the spinal cord dorsal horn (SCDH) is one of the mechanisms involved in central sensitization during chronic pain. Previously, this laboratory created a spatio-temporal knockout (KO) of the N-methyl-d-aspartate receptor I (NR1) subunit in the mouse SCDH. The NR1 KO completely blocks NR1 gene and subsequent NMDA receptor expression and function in SCDH neurons. In the NR1 KO mice, the mechanical and cold allodynia induced at 24 h after complete Freund's adjuvant (CFA) was reduced. However, the protective effects of KO were transient and were not seen at 48 h after CFA. These observations suggest the presence of NMDA-independent pathways that contribute to CFA-induced pain. CFA induces the activation of several signaling cascades in the SCDH, including protein kinase C (PKC)gamma and extracellular signal-regulated kinases (ERK1/2). The phosphorylation of PKCgamma and ERK1/2 was inhibited in the SCDH of NR1 KO mice up to 48 h after CFA treatment, suggesting that these pathways are NMDA receptor-dependent. Interestingly, neuronal cyclooxygenase (COX) -2 expression and microglial p38 phosphorylation were induced in the SCDH of the NR1 KO at 48 h after CFA. Our findings provide evidence that inflammatory reactions are responsible for the recurrence of pain after NR1 KO in the SCDH.
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Affiliation(s)
- H T Cheng
- Department of Pharmacology, Weill Medical College, Cornell University, New York, NY 10065, USA.
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Murotomi K, Takagi N, Takayanagi G, Ono M, Takeo S, Tanonaka K. mGluR1 antagonist decreases tyrosine phosphorylation of NMDA receptor and attenuates infarct size after transient focal cerebral ischemia. J Neurochem 2008; 105:1625-34. [PMID: 18248625 DOI: 10.1111/j.1471-4159.2008.05260.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The contribution of metabotropic glutamate receptors to brain injury after in vivo cerebral ischemia remains to be determined. We investigated the effects of the metabotropic glutamate receptor 1 (mGluR1) antagonist LY367385 on brain injury after transient (90 min) middle cerebral artery occlusion in the rat and sought to explore their mechanisms. The intravenous administration of LY367385 (10 mg/kg) reduced the infarct volume at 24 h after the start of reperfusion. As the Gq-coupled mGluR1 receptor is known to activate the PKC/Src family kinase cascade, we focused on changes in the activation and amount of these kinases. Transient focal ischemia increased the amount of activated tyrosine kinase Src and PKC in the post-synaptic density (PSD) at 4 h of reperfusion. The administration of LY367385 attenuated the increases in the amounts of PSD-associated PKCgamma and Src after transient focal ischemia. We further investigated phosphorylation of the NMDA receptor, which is a major target of Src family kinases to modulate the function of the receptor. Transient focal ischemia increased the tyrosine phosphorylation of NMDA receptor subunits NR2A and NR2B. Tyrosine phosphorylation of NR2A, but not that of NR2B, in the PSD at 4 h of reperfusion was inhibited by LY367385. These results suggest that the mGluR1 after transient focal ischemia is involved in the activation of Src, which may be linked to the modification of properties of the NMDA receptor and the development of cerebral infarction.
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Affiliation(s)
- Kazutoshi Murotomi
- Department of Molecular and Cellular Pharmacology, Tokyo University of Pharmacy & Life Sciences, Tokyo, Japan
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46
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Burrell BD, Li Q. Co-induction of long-term potentiation and long-term depression at a central synapse in the leech. Neurobiol Learn Mem 2008; 90:275-9. [PMID: 18182311 DOI: 10.1016/j.nlm.2007.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 11/27/2007] [Accepted: 11/28/2007] [Indexed: 12/11/2022]
Abstract
Most studies of long-term potentiation (LTP) have focused on potentiation induced by the activation of postsynaptic NMDA receptors (NMDARs). However, it is now apparent that NMDAR-dependent signaling processes are not the only form of LTP operating in the brain [Malenka, R. C., & Bear, M. F. (2004). LTP and LTD: An embarrassment of riches. Neuron, 44, 5-21]. Previously, we have observed that LTP in leech central synapses made by the touch mechanosensory neurons onto the S interneuron was NMDAR-independent [Burrell, B. D., & Sahley, C. L. (2004). Multiple forms of long-term potentiation and long-term depression converge on a single interneuron in the leech CNS. Journal of Neuroscience, 24, 4011-4019]. Here we examine the cellular mechanisms mediating T-to-S (T-->S) LTP and find that its induction requires activation of metabotropic glutamate receptors (mGluRs), voltage-dependent Ca(2+) channels (VDCCs) and protein kinase C (PKC). Surprisingly, whenever LTP was pharmacologically inhibited, long-term depression (LTD) was observed at the tetanized synapse, indicating that LTP and LTD were activated at the same time in the same synaptic pathway. This co-induction of LTP and LTD likely plays an important role in activity-dependent regulation of synaptic transmission.
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Affiliation(s)
- Brian D Burrell
- Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, 414 E. Clark St., Vermillion, SD 57069, USA.
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Oyasu M, Fujimiya M, Kashiwagi K, Ohmori S, Imaeda H, Saito N. Immunogold electron microscopic demonstration of distinct submembranous localization of the activated gammaPKC depending on the stimulation. J Histochem Cytochem 2007; 56:253-65. [PMID: 18040079 DOI: 10.1369/jhc.7a7291.2007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We examined the precise intracellular translocation of gamma subtype of protein kinase C (gammaPKC) after various extracellular stimuli using confocal laser-scanning fluorescent microscopy (CLSM) and immunogold electron microscopy. By CLSM, treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) resulted in a slow and irreversible accumulation of green fluorescent protein (GFP)-tagged gammaPKC (gammaPKC-GFP) on the plasma membrane. In contrast, treatment with Ca(2+) ionophore and activation of purinergic or NMDA receptors induced a rapid and transient membrane translocation of gammaPKC-GFP. Although each stimulus resulted in PKC localization at the plasma membrane, electron microscopy revealed that gammaPKC showed a subtle but significantly different localization depending on stimulation. Whereas TPA and UTP induced a sustained localization of gammaPKC-GFP on the plasma membrane, Ca(2+) ionophore and NMDA rapidly translocated gammaPKC-GFP to the plasma membrane and then restricted gammaPKC-GFP in submembranous area (<500 nm from the plasma membrane). These results suggest that Ca(2+) influx alone induced the association of gammaPKC with the plasma membrane for only a moment and then located this enzyme at a proper distance in a touch-and-go manner, whereas diacylglycerol or TPA tightly anchored this enzyme on the plasma membrane. The distinct subcellular targeting of gammaPKC in response to various stimuli suggests a novel mechanism for PKC activation.
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Affiliation(s)
- Miho Oyasu
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan
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Barnett ME, Madgwick DK, Takemoto DJ. Protein kinase C as a stress sensor. Cell Signal 2007; 19:1820-9. [PMID: 17629453 PMCID: PMC1986756 DOI: 10.1016/j.cellsig.2007.05.014] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Revised: 05/24/2007] [Accepted: 05/25/2007] [Indexed: 11/22/2022]
Abstract
While there are many reviews which examine the group of proteins known as protein kinase C (PKC), the focus of this article is to examine the cellular roles of two PKCs that are important for stress responses in neurological tissues (PKC gamma and epsilon) and in cardiac tissues (PKC epsilon). These two kinases, in particular, seem to have overlapping functions and interact with an identical target, connexin 43 (Cx43), a gap junction protein which is central to proper control of signals in both tissues. While PKC gamma and PKC epsilon both help protect neural tissue from ischemia, PKC epsilon is the primary PKC isoform responsible for responding to decreased oxygen, or ischemia, in the heart. Both do this through Cx43. It is clear that both PKC gamma and PKC epsilon are necessary for protection from ischemia. However, the importance of these kinases has been inferred from preconditioning experiments which demonstrate that brief periods of hypoxia protect neurological and cardiac tissues from future insults, and that this depends on the activation, translocation, or ability for PKC gamma and/or PKC epsilon to interact with distinct cellular targets, especially Cx43. This review summarizes the recent findings which define the roles of PKC gamma and PKC epsilon in cardiac and neurological functions and their relationships to ischemia/reperfusion injury. In addition, a biochemical comparison of PKC gamma and PKC epsilon and a proposed argument for why both forms are present in neurological tissue while only PKC epsilon is present in heart, are discussed. Finally, the biochemistry of PKCs and future directions for the field are discussed, in light of this new information.
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Affiliation(s)
- Micheal E Barnett
- Department of Biochemistry, Kansas State University, Manhattan, Kansas 66506-3902, USA.
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Horne EA, Dell'Acqua ML. Phospholipase C is required for changes in postsynaptic structure and function associated with NMDA receptor-dependent long-term depression. J Neurosci 2007; 27:3523-34. [PMID: 17392468 PMCID: PMC6672111 DOI: 10.1523/jneurosci.4340-06.2007] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
NMDA receptor (NMDAR)-dependent hippocampal synaptic plasticity underlying learning and memory coordinately regulates dendritic spine structure and AMPA receptor (AMPAR) postsynaptic strength through poorly understood mechanisms. Induction of long-term depression (LTD) activates protein phosphatase 2B/calcineurin (CaN), leading to dendritic spine shrinkage through actin depolymerization and AMPAR depression through receptor dephosphorylation and internalization. The scaffold proteins A-kinase-anchoring protein 79/150 (AKAP79/150) and postsynaptic density 95 (PSD95) form a complex that controls the opposing actions of the cAMP-dependent protein kinase (PKA) and CaN in regulation of AMPAR phosphorylation. The AKAP79/150-PSD95 complex is disrupted in hippocampal neurons during LTD coincident with internalization of AMPARs, decreases in PSD95 levels, and loss of AKAP79/150 and PKA from spines. AKAP79/150 is targeted to spines through binding F-actin and the phospholipid phosphatidylinositol-(4,5)-bisphosphate (PIP2). Previous electrophysiological studies have demonstrated that inhibition of phospholipase C (PLC)-catalyzed hydrolysis of PIP2 inhibits NMDAR-dependent LTD; however, the signaling mechanisms that link PLC activation to alterations in dendritic spine structure and AMPAR function in LTD are unknown. We show here that NMDAR stimulation of PLC in cultured hippocampal neurons is necessary for AKAP79/150 loss from spines and depolymerization of spine actin. Importantly, we demonstrate that NMDAR activation of PLC is also necessary for decreases in spine PSD95 levels and AMPAR internalization. Thus, PLC signaling is required for structural and functional changes in spine actin, PSD scaffolding, and AMPAR trafficking underlying postsynaptic expression of LTD.
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Affiliation(s)
| | - Mark L. Dell'Acqua
- Department of Pharmacology
- Program in Neuroscience, School of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado 80045
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Abstract
Protein kinase Cs (PKCs) are implicated in many forms of synaptic plasticity. However, the specific isoform(s) of PKC that underlie(s) these events are often not known. We have used Aplysia as a model system in order to investigate the isoform specificity of PKC actions due to the presence of fewer isoforms and a large number of documented physiological roles for PKC in synaptic plasticity in this system. In particular, we have shown that distinct isoforms mediate distinct types of synaptic plasticity induced by the same neurotransmitter: The novel calcium-independent PKC Apl II is required for actions mediated by serotonin (5-HT) alone, while the classical calcium-dependent PKC Apl I is required for actions mediated when 5-HT is coupled to activity. We will discuss the reasons for PKC isoform specificity, assess the tools used to uncover isoform specificity, and discuss the implications of isoform specificity for understanding the roles of PKC in regulating synaptic plasticity.
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Affiliation(s)
- Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
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