Connexins in Ischemia-Induced Neuronal Death

Summary

Principal Investigator: MICHAEL V BENNETT
Abstract: Transient, but severe global ischemia, observed in patients during cardiac arrest and cardiac surgery or induced experimentally in animals, induces selective and delayed neurodegeneration. Pyramidal cells in CA1 are the most sensitive; CA3 and granule cells of the dentate gyrus (DG) are resistant to ischemic damage, and GABAergic interneurons in CA1 also survive. The molecular mechanisms underlying this pattern of neuronal death are not well understood. The proposed research aims to study the role of gap junctions during the several days of "maturation" of neuronal injury after global ischemia. Recent findings from this laboratory indicate that global ischemia triggers a selective upregulation of Cx36 (and Cx32) protein expression in GABAergic interneurons of the vulnerable CA1 at times prior to the onset of neuronal death, consistent with a role in the survival of these neurons. Moreover, CA1 neurons in Cx32 (Y/-) mice exhibit enhanced vulnerability to global ischemia-induced neuronal death. These data suggest that increased inhibition of pyramidal cells through synchronization of inhibitory interneurons may be neuroprotective. Gap junctions between astrocytes are also thought to have a role in postischemic neuronal death. Dying cells can kill resistant neighboring glial cells via glial "fratricide" (bystander death) and thereby propagate injury to neighboring regions. On the other hand, gap junctional coupling of astrocytes mediates metabolic cooperation among them and attenuates neuronal death in models of oxidative stress. The underlying hypothesis of this proposal is that gap junctions play important roles in determining neuronal death and survival following global ischemia. The research plan for the next five years focuses on changes in the abundance, distribution and molecular and biophysical properties of brain gap junctions following neurological insult. Specific Aims are 1. Characterize ischemia-induced alterations in connexin expression and gap junction properties in the vulnerable CA1 and resistant CA3 and dentate gyrus of rats and mice. Experiments will examine global ischemia-induced changes in coupling of inhibitory interneurons and expression of connexin proteins by immunocytochemistry and Western blotting and of connexin mRNAs by in situ hybridization and. Experiments will determine the effects of acute knockdown of specific connexins by antisense oligonucleotides on neuronal vulnerability and will examine neuronal vulnerability in Cx32(Y/-) mice, Cx36(-/-) mice and mice deficient in astrocyte Cx43. 2. Examine effects of oxygen/glucose deprivation on hippocampal slice cultures by immunocytochemistry, in situ hybridization and electrophysiological methods. To examine ischemia-induced changes in gap junction properties in acute slices and organotypic hippocampal slice cultures by electrophysiological methods and image analysis. The proposed research is expected to impact on the development of new treatment strategies for intervention in global ischemia, a debilitating and often fatal trauma associated with cardiac arrest in humans. Moreover, this study has important implications for research on other neurodegenerative disorders including focal ischemia, epilepsy, AIDS encephalopathy, and Alzheimer's disease.
Funding Period: 2002-12-15 - 2008-11-30
more information: NIH RePORT

Top Publications

  1. ncbi The ATP required for potentiation of skeletal muscle contraction is released via pannexin hemichannels
    Manuel A Riquelme
    Departamento de Fisiologia, Pontificia Universidad Catolica de Chile, Santiago 8, Chile
    Neuropharmacology 75:594-603. 2013
  2. pmc FGF-1 induces ATP release from spinal astrocytes in culture and opens pannexin and connexin hemichannels
    Juan M Garré
    Facultad de Medicina, Universidad de la República Oriental del Uruguay, C P 11800 Montevideo, Uruguay
    Proc Natl Acad Sci U S A 107:22659-64. 2010
  3. pmc Hypoxia in high glucose followed by reoxygenation in normal glucose reduces the viability of cortical astrocytes through increased permeability of connexin 43 hemichannels
    Juan A Orellana
    Departamento de Ciencias Fisiologicas, Pontificia Universidad Catolica de Chile, Alameda 340, Santiago, Chile
    Glia 58:329-43. 2010
  4. pmc Differences in NMDA receptor expression during human development determine the response of neurons to HIV-tat-mediated neurotoxicity
    E A Eugenin
    Department of Pathology, Albert Einstein College of Medicine, Forchheimer 727, 1300 Morris Park Avenue, Bronx, NY 10461, USA
    Neurotox Res 19:138-48. 2011
  5. pmc pH-dependent modulation of voltage gating in connexin45 homotypic and connexin45/connexin43 heterotypic gap junctions
    Nicolas Palacios-Prado
    Dominick P Purpura Department of Neuroscience and Department of Anesthesiology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
    Proc Natl Acad Sci U S A 107:9897-902. 2010
  6. ncbi Cell membrane permeabilization via connexin hemichannels in living and dying cells
    Juan C Saez
    Departamento de Ciencias Fisiologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile
    Exp Cell Res 316:2377-89. 2010
  7. pmc EphB controls NMDA receptor function and synaptic targeting in a subunit-specific manner
    Mark J Nolt
    Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania 19104, USA
    J Neurosci 31:5353-64. 2011
  8. pmc SNAP-25 is a target of protein kinase C phosphorylation critical to NMDA receptor trafficking
    C Geoffrey Lau
    Rose F Kennedy Center, Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA
    J Neurosci 30:242-54. 2010
  9. pmc Connexin 32 increases the proliferative response of Schwann cells to neuregulin-1 (Nrg1)
    Mona Freidin
    Department of Neurology, State University of New York Downstate at Brooklyn, Brooklyn NY 10021, USA
    Proc Natl Acad Sci U S A 106:3567-72. 2009
  10. pmc Modulation of brain hemichannels and gap junction channels by pro-inflammatory agents and their possible role in neurodegeneration
    Juan A Orellana
    Departamento de Ciencias Fisiologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile
    Antioxid Redox Signal 11:369-99. 2009

Scientific Experts

  • Juan A Orellana
  • Juan C Saez
  • Charles K Abrams
  • Mona Freidin
  • Michael V L Bennett
  • R Suzanne Zukin
  • Mauricio A Retamal
  • Kyung Min Noh
  • C Geoffrey Lau
  • Takahiro Miyawaki
  • Toshihiro Mashiko
  • Manuel A Riquelme
  • E A Eugenin
  • Mark J Nolt
  • Nicolas Palacios-Prado
  • Juan M Garré
  • Feliksas F Bukauskas
  • Yukihiro Takayasu
  • Alma Rodenas-Ruano
  • Joan W Berman
  • Yupeng Yang
  • Ying Lin
  • Kenji F Shoji
  • Eliseo A Eugenin
  • Kurt A Schalper
  • Luigi Formisano
  • V Arvydas Skeberdis
  • Pablo E Castillo
  • Jose L Vega
  • Marina Frank
  • Mauricio P Boric
  • Klaus Willecke
  • Luis A Cea
  • Hannah Monyer
  • Joel Passer
  • R S Zukin
  • E O Major
  • Matthew S Kayser
  • Martin Hruska
  • Sean I Sheffler-Colins
  • Jessica Murphy
  • M V L Bennett
  • J E King
  • Matthew B Dalva
  • J E Hazleton
  • Veronica Abudara
  • Vytenis A Skeberdis
  • Juan Lerma
  • Luis Barbeito
  • Patricia Cassina
  • Ana V Paternain
  • Mindaugas Pranevicius
  • Stephen W Briggs
  • Koichi Takeuchi
  • Elizabeth A Jonas
  • Dimitry Ofengeim
  • Laura Bonanni
  • Richard J Flannery
  • Sho Fujisawa
  • Tina M Calderon
  • Jessie E King
  • Avindra Nath
  • Sylvia O Suadicani
  • Constanza J Cortes
  • Vivien Chevaleyre
  • Rafael Yuste
  • Luis Reuss
  • Jesse H Goldberg
  • Diana L Pettit
  • Hidenori Yokota

Detail Information

Publications20

  1. ncbi The ATP required for potentiation of skeletal muscle contraction is released via pannexin hemichannels
    Manuel A Riquelme
    Departamento de Fisiologia, Pontificia Universidad Catolica de Chile, Santiago 8, Chile
    Neuropharmacology 75:594-603. 2013
    ..This article is part of the Special Issue Section entitled 'Current Pharmacology of Gap Junction Channels and Hemichannels'...
  2. pmc FGF-1 induces ATP release from spinal astrocytes in culture and opens pannexin and connexin hemichannels
    Juan M Garré
    Facultad de Medicina, Universidad de la República Oriental del Uruguay, C P 11800 Montevideo, Uruguay
    Proc Natl Acad Sci U S A 107:22659-64. 2010
    ..These changes in HCs and gap junction channels may promote inflammation and deprive neurons of astrocyte-mediated protection in spinal cord trauma and neurodegenerative disease...
  3. pmc Hypoxia in high glucose followed by reoxygenation in normal glucose reduces the viability of cortical astrocytes through increased permeability of connexin 43 hemichannels
    Juan A Orellana
    Departamento de Ciencias Fisiologicas, Pontificia Universidad Catolica de Chile, Alameda 340, Santiago, Chile
    Glia 58:329-43. 2010
    ..Cx43 hemichannels may be a novel therapeutic target to reduce cell death following stroke, particularly in hyperglycemic conditions...
  4. pmc Differences in NMDA receptor expression during human development determine the response of neurons to HIV-tat-mediated neurotoxicity
    E A Eugenin
    Department of Pathology, Albert Einstein College of Medicine, Forchheimer 727, 1300 Morris Park Avenue, Bronx, NY 10461, USA
    Neurotox Res 19:138-48. 2011
    ..We propose that this difference may be due to low expression of the NR2A subunit. These findings are important for an understanding of the many differences among tissue culture systems and species used to study HIV-tat-mediated toxicity...
  5. pmc pH-dependent modulation of voltage gating in connexin45 homotypic and connexin45/connexin43 heterotypic gap junctions
    Nicolas Palacios-Prado
    Dominick P Purpura Department of Neuroscience and Department of Anesthesiology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
    Proc Natl Acad Sci U S A 107:9897-902. 2010
    ..7, between the pK(a)s of Cx45 and Cx43-EGFP (approximately 6.5) homotypic GJs. In summary, pH(i) significantly modulates junctional conductance of Cx45 by affecting both V(j) gating and number of functional channels...
  6. ncbi Cell membrane permeabilization via connexin hemichannels in living and dying cells
    Juan C Saez
    Departamento de Ciencias Fisiologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile
    Exp Cell Res 316:2377-89. 2010
    ....
  7. pmc EphB controls NMDA receptor function and synaptic targeting in a subunit-specific manner
    Mark J Nolt
    Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania 19104, USA
    J Neurosci 31:5353-64. 2011
    ..These findings demonstrate that, in the mature nervous system, EphBs are key regulators of the synaptic localization of NMDARs...
  8. pmc SNAP-25 is a target of protein kinase C phosphorylation critical to NMDA receptor trafficking
    C Geoffrey Lau
    Rose F Kennedy Center, Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA
    J Neurosci 30:242-54. 2010
    ..These findings identify SNAP-25 as the target of PKC phosphorylation critical to PKC-dependent incorporation of synaptic NMDARs and document a postsynaptic action of this major SNARE protein relevant to synaptic plasticity...
  9. pmc Connexin 32 increases the proliferative response of Schwann cells to neuregulin-1 (Nrg1)
    Mona Freidin
    Department of Neurology, State University of New York Downstate at Brooklyn, Brooklyn NY 10021, USA
    Proc Natl Acad Sci U S A 106:3567-72. 2009
    ..These results suggest a link between Cx32 expression and Nrg1 regulation of SC proliferation that does not involve Cx32-mediated intercellular communication...
  10. pmc Modulation of brain hemichannels and gap junction channels by pro-inflammatory agents and their possible role in neurodegeneration
    Juan A Orellana
    Departamento de Ciencias Fisiologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile
    Antioxid Redox Signal 11:369-99. 2009
    ..These changes are likely to occur in diverse cell types of the CNS and contribute to neurodegeneration during inflammatory process...
  11. pmc Developmental switch in requirement for PKA RIIbeta in NMDA-receptor-dependent synaptic plasticity at Schaffer collateral to CA1 pyramidal cell synapses
    Yupeng Yang
    Dominick P Purpura Department of Neuroscience, Kennedy Center Room 602B, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
    Neuropharmacology 56:56-65. 2009
    ..These findings indicate that distinct PKA isoforms may subserve distinct forms of synaptic plasticity and are consistent with a developmental switch in the signaling cascades required for LTP induction...
  12. ncbi Protein kinase A regulates calcium permeability of NMDA receptors
    V Arvydas Skeberdis
    Rose F Kennedy Center for Research in Mental Retardation and Developmental Disabilities, Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA
    Nat Neurosci 9:501-10. 2006
    ..Our data link PKA-dependent synaptic plasticity to Ca2+ signaling in spines and thus provide a new mechanism whereby PKA regulates the induction of LTP...
  13. pmc S-nitrosylation and permeation through connexin 43 hemichannels in astrocytes: induction by oxidant stress and reversal by reducing agents
    Mauricio A Retamal
    Departamento de Ciencias Fisiologicas, Pontificia Universidad Catolica de Chile, Santiago 6513492, Chile
    Proc Natl Acad Sci U S A 103:4475-80. 2006
    ....
  14. pmc Properties of human connexin 31, which is implicated in hereditary dermatological disease and deafness
    Charles K Abrams
    Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
    Proc Natl Acad Sci U S A 103:5213-8. 2006
    ..These findings provide an important first step in evaluating the pathogenesis of inherited human diseases associated with mutations in the gene for Cx31...
  15. pmc Ischemic insults promote epigenetic reprogramming of mu opioid receptor expression in hippocampal neurons
    Luigi Formisano
    Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
    Proc Natl Acad Sci U S A 104:4170-5. 2007
    ..These findings implicate MORs in ischemia-induced death of CA1 pyramidal neurons and document epigenetic remodeling of expression of OPRM1 in CA1 inhibitory interneurons...
  16. pmc HIV-tat induces formation of an LRP-PSD-95- NMDAR-nNOS complex that promotes apoptosis in neurons and astrocytes
    Eliseo A Eugenin
    Department of Pathology and Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
    Proc Natl Acad Sci U S A 104:3438-43. 2007
    ..These findings implicate the complex in HIV-induced neuronal apoptosis and suggest therapeutic targets for intervention in the pathogenesis of NeuroAIDS...
  17. pmc Opening of connexin 43 hemichannels is increased by lowering intracellular redox potential
    Mauricio A Retamal
    Núcleo Milenio Inmunología e Inmunoterapia, Departamento de Ciencias Fisiologicas, Pontificia Universidad Catolica de Chile, Santiago 4860, Chile
    Proc Natl Acad Sci U S A 104:8322-7. 2007
    ..These findings suggest that lowering intracellular redox potential increases the opening of Cx43 and Cx43-EGFP hemichannels, possibly by action on cytoplasmic cysteine residues in the connexin C terminus...
  18. ncbi Possible involvement of different connexin43 domains in plasma membrane permeabilization induced by ischemia-reperfusion
    Mauricio A Retamal
    Departamento de Ciencias Fisiologicas, Pontificia Universidad Catolica de Chile, Alameda 340, Santiago, Chile
    J Membr Biol 218:49-63. 2007
    ....
  19. pmc Ischemic preconditioning blocks BAD translocation, Bcl-xL cleavage, and large channel activity in mitochondria of postischemic hippocampal neurons
    Takahiro Miyawaki
    Dominick P Purpura Department of Neuroscience, Rose F Kennedy Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
    Proc Natl Acad Sci U S A 105:4892-7. 2008
    ..These findings implicate PI3K/Akt signaling in maintenance of the integrity of the mitochondrial outer membrane...
  20. pmc Blockade of calcium-permeable AMPA receptors protects hippocampal neurons against global ischemia-induced death
    Kyung Min Noh
    Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
    Proc Natl Acad Sci U S A 102:12230-5. 2005
    ..This receptor subtype appears to be an important therapeutic target for intervention in ischemia-induced neuronal death in humans...