Mitochondrial ion channels in hypoxic neurons

Summary

Principal Investigator: Elizabeth Ann Jonas
Abstract: Stroke is a major cause of morbidity and mortality in the United States and presents challenges in the development of disease prevention strategies. Deprivation of nutrients and oxygen supply to brain cells produces immediate death in the most severely affected cells and delayed cell death in some cells that are placed at risk at the first onset of ischemia. The latter form of neuronal death is orchestrated by BCL-2 family proteins, which also regulate cell death during nervous system development. BCL-2 family proteins are present in mitochondrial membranes and become activated to form large conductance ion channel activity in response to many death stimuli, including a low concentration of cellular oxygen. The relationship of the channel activity to the onset of cell death is as yet poorly understood. We have developed patch clamp techniques to record mitochondrial ion channel activity within living neurons and to study the ion channel activity of BCL-2 family proteins in mitochondria isolated from brain. In comparing the channel activity of recombinant BCL-2 family proteins to endogenous activity, we find that the recombinant N-truncated form of BCL-xL, (?N BCL-xL) that is produced by acute proteolytic processing of full length BCL-xL in response to death stimuli, has biophysical and pharmacological similarities to an endogenous mitochondrial channel that appears during transient global ischemia in mammalian brain. The onset of channel activity of ?N BCL-xL may initiate a series of molecular events that leads to selective, delayed cell death in vulnerable CA1 neurons of the hippocampus. We hypothesize that inhibition of the ?N BCL-xL channel activity with the specific inhibitor of BCL-xL, ABT-737, will block cell death in these sensitive neurons after ischemia. Furthermore, if proteolytic processing of full length BCL-xL is necessary for cell death, then hippocampal neurons of a mouse that lacks a cleavable form of BCL-xL may fail to form ?N BCL-xL and fail to die after ischemic insult. These studies will test the hypothesis that ?N BCL-xL is the key regulator of cell death in hippocampal neurons. In addition, these studies will attempt to elucidate the molecular mechanisms underlying cell death in neurons after ischemic brain injury with an eye to developing strategies to combat stroke. PUBLIC HEALTH RELEVANCE: Stroke is a major cause of morbidity and mortality in the United States. We have found that mitochondrial ion channel activity of the pro- and anti-death BCL-2 protein family contributes to the physiological and pathological function of neurons. We hypothesize that in the setting of brain ischemia, such channel activity leads to cell death in the brain and that this death can be prevented by a pharmacological inhibitor of BCL-2-induced mitochondrial ion channels.
Funding Period: 2003-04-01 - 2014-02-28
more information: NIH RePORT

Top Publications

  1. ncbi Zinc-dependent multi-conductance channel activity in mitochondria isolated from ischemic brain
    Laura Bonanni
    Department of Oncology and Neuroscience and Center for Excellence on Aging, d Annunzio Foundation, Università G d Annunzio Chieti, 66013 Chieti, Italy
    J Neurosci 26:6851-62. 2006
  2. pmc A Bcl-xL-Drp1 complex regulates synaptic vesicle membrane dynamics during endocytosis
    Hongmei Li
    Department of Internal Medicine, Yale University, New Haven, Connecticut 06520, USA
    Nat Cell Biol 15:773-85. 2013
  3. pmc Multipolar functions of BCL-2 proteins link energetics to apoptosis
    J Marie Hardwick
    W Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
    Trends Cell Biol 22:318-28. 2012
  4. pmc N-terminally cleaved Bcl-xL mediates ischemia-induced neuronal death
    Dimitry Ofengeim
    Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
    Nat Neurosci 15:574-80. 2012
  5. pmc Effects of dexpramipexole on brain mitochondrial conductances and cellular bioenergetic efficiency
    Kambiz N Alavian
    Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
    Brain Res 1446:1-11. 2012
  6. pmc Bcl-xL regulates mitochondrial energetics by stabilizing the inner membrane potential
    Ying bei Chen
    Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
    J Cell Biol 195:263-76. 2011
  7. pmc Bcl-xL regulates metabolic efficiency of neurons through interaction with the mitochondrial F1FO ATP synthase
    Kambiz N Alavian
    Department of Internal Medicine, Yale University, New Haven, Connecticut 06520, USA
    Nat Cell Biol 13:1224-33. 2011
  8. pmc Molecular participants in mitochondrial cell death channel formation during neuronal ischemia
    Elizabeth Ann Jonas
    Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
    Exp Neurol 218:203-12. 2009
  9. pmc Bcl-x L increases mitochondrial fission, fusion, and biomass in neurons
    Sarah B Berman
    W Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
    J Cell Biol 184:707-19. 2009
  10. pmc PKC-induced intracellular trafficking of Ca(V)2 precedes its rapid recruitment to the plasma membrane
    Yalan Zhang
    Department of Pharmacology, Section of Endocrinology, Yale School of Medicine, New Haven, Connecticut 06520, USA
    J Neurosci 28:2601-12. 2008

Detail Information

Publications14

  1. ncbi Zinc-dependent multi-conductance channel activity in mitochondria isolated from ischemic brain
    Laura Bonanni
    Department of Oncology and Neuroscience and Center for Excellence on Aging, d Annunzio Foundation, Università G d Annunzio Chieti, 66013 Chieti, Italy
    J Neurosci 26:6851-62. 2006
    ....
  2. pmc A Bcl-xL-Drp1 complex regulates synaptic vesicle membrane dynamics during endocytosis
    Hongmei Li
    Department of Internal Medicine, Yale University, New Haven, Connecticut 06520, USA
    Nat Cell Biol 15:773-85. 2013
    ..Mutagenesis studies suggest that formation of the Bcl-xL-Drp1 complex is necessary for the enhanced rate of vesicle endocytosis produced by Bcl-xL, thus providing a mechanism for presynaptic plasticity. ..
  3. pmc Multipolar functions of BCL-2 proteins link energetics to apoptosis
    J Marie Hardwick
    W Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
    Trends Cell Biol 22:318-28. 2012
    ..Even their sub-mitochondrial localizations remain controversial. Here we attempt to integrate seemingly conflicting information with the prospect that BCL-2 proteins themselves may be the critical crosstalk between life and death...
  4. pmc N-terminally cleaved Bcl-xL mediates ischemia-induced neuronal death
    Dimitry Ofengeim
    Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
    Nat Neurosci 15:574-80. 2012
    ..These findings suggest that truncated Bcl-x(L) could be a potentially important therapeutic target in ischemic brain injury...
  5. pmc Effects of dexpramipexole on brain mitochondrial conductances and cellular bioenergetic efficiency
    Kambiz N Alavian
    Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
    Brain Res 1446:1-11. 2012
    ..These data indicate that DEX increases the efficiency of oxidative phosphorylation, possibly by inhibition of a CSA-sensitive mitochondrial conductance...
  6. pmc Bcl-xL regulates mitochondrial energetics by stabilizing the inner membrane potential
    Ying bei Chen
    Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
    J Cell Biol 195:263-76. 2011
    ..Thus, by bolstering mitochondrial energetic capacity, Bcl-x(L) may contribute importantly to cell survival independently of other Bcl-2 family proteins...
  7. pmc Bcl-xL regulates metabolic efficiency of neurons through interaction with the mitochondrial F1FO ATP synthase
    Kambiz N Alavian
    Department of Internal Medicine, Yale University, New Haven, Connecticut 06520, USA
    Nat Cell Biol 13:1224-33. 2011
    ..Our findings indicate that increased mitochondrial efficiency contributes to the enhanced synaptic efficacy found in Bcl-x(L)-expressing neurons...
  8. pmc Molecular participants in mitochondrial cell death channel formation during neuronal ischemia
    Elizabeth Ann Jonas
    Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
    Exp Neurol 218:203-12. 2009
    ..The variety of possible molecular participants within the ion channel complex may be matched only by the variety of different types of programmed cell death...
  9. pmc Bcl-x L increases mitochondrial fission, fusion, and biomass in neurons
    Sarah B Berman
    W Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
    J Cell Biol 184:707-19. 2009
    ..Deficits in these Bcl-x(L)-dependent mechanisms may be critical in neuronal dysfunction during the earliest phases of neurodegeneration, long before commitment to cell death...
  10. pmc PKC-induced intracellular trafficking of Ca(V)2 precedes its rapid recruitment to the plasma membrane
    Yalan Zhang
    Department of Pharmacology, Section of Endocrinology, Yale School of Medicine, New Haven, Connecticut 06520, USA
    J Neurosci 28:2601-12. 2008
    ..Only after activation of PKC do Ca(V)2 channels associate with actin and undergo insertion into the plasma membrane...
  11. pmc Bcl-xL induces Drp1-dependent synapse formation in cultured hippocampal neurons
    Hongmei Li
    Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
    Proc Natl Acad Sci U S A 105:2169-74. 2008
    ..These findings suggest that Bcl-xL positively regulates Drp1 to alter mitochondrial function in a manner that stimulates synapse formation...
  12. pmc Bcl-xL inhibitor ABT-737 reveals a dual role for Bcl-xL in synaptic transmission
    John A Hickman
    Institut de Recherches Servier, Croissy sur Seine, France
    J Neurophysiol 99:1515-22. 2008
    ..These observations support the possibility that endogenous proteolysis or a functionally equivalent modification of BCL-xL is responsible for the deleterious effects of hypoxia on synaptic activity...
  13. pmc Contributions of Bcl-xL to acute and long term changes in bioenergetics during neuronal plasticity
    Elizabeth A Jonas
    Dept of Internal Medicine, P O Box 208001, Yale University School of Medicine, New Haven, CT 06520, USA Dept of Neurobiology, P O Box 208020, Yale University School of Medicine, New Haven, CT 06520, USA Electronic address
    Biochim Biophys Acta 1842:1168-78. 2014
    ..Bcl-xL is crucial to the normal health of neurons and synapses and its malfunction may contribute to neurodegenerative disease...

Research Grants30

  1. Molecular Mechanisms linking Aging, Abeta Proteotoxicity and Neurodegeneration
    Jeffery W Kelly; Fiscal Year: 2013
    ..abstract_text> ..
  2. Pacific NorthWest Regional Center of Excellence (PNWRCE)
    Jay A Nelson; Fiscal Year: 2013
    ..pseudomallei host pathogen response during both the septicemic as well as the intracellular phases of the disease. ..
  3. Histone deacetylases - therapeutic targets for functional restoration after strok
    SEAN PADRAIG MURPHY; Fiscal Year: 2013
    ..Selected drugs will be tested to reveal what functional benefits they confer on the recovery of mice from stroke injury. ..
  4. Blood Coagulation Protein - Metal Ion - Lipid Interactions
    Francis J Castellino; Fiscal Year: 2013
    ..This proposal is concerned with the complex mechanisms of action of the conantokins in vitro and in vivo and relating these properties to their neuroprotective effects in a model of occlusive stroke. ..
  5. Astrocytes and Ischemic Brain Injury
    Rona G Giffard; Fiscal Year: 2013
    ....
  6. INITIATION OF HUMAN LABOR: PREVENTION OF PREMATURITY
    Carole R Mendelson; Fiscal Year: 2013
    ..We propose that these interrelated projects, carried out by a highly interactive research team, will achieve the long-range goals of this Program and contribute to a reduction in the incidence of preterm birth. ..
  7. BAX/BAK-Mediated Mitochondrial Outer Membrane Permeabilization in Apoptosis
    Kyoung Joon Oh; Fiscal Year: 2013
    ..This in turn will provide valuable insights in designing therapeutic means to control the cell death processes either by enhancing apoptosis in cancer or by suppressing it in strokes or neurodegenerative diseases. ..
  8. ELECTROPHYSIOLOGY OF NUCLEAR MEMBRANE INSP3 RECEPTOR
    J Kevin Foskett; Fiscal Year: 2013
    ....
  9. Signaling Cell Death from the Endoplasmic Reticulum
    Scott A Oakes; Fiscal Year: 2013
    ..This projects sets out to define how cellular stress normally leads to apoptosis and what goes wrong with this process in cancer-in the hopes of finding new therapeutic targets through which to kill tumor cells. ..
  10. Structural bases of the functions of RNA-protein machines
    THOMAS ARTHUR STEITZ; Fiscal Year: 2013
    ..Also of interest will be the ways in which the structures and properties of RNA molecules can be utilized to carry out various biological functions often analogous to those performed by proteins. ..
  11. Neurohumoral control of veins in hypertension
    Gregory D Fink; Fiscal Year: 2013
    ..This project tests the idea that altered structure or function of veins also may cause hypertension, and that it may be possible to treat hypertension using drugs that affect veins. ..
  12. Role of a pro-apoptotic Bcl-2 protein in the survival and death of leukemia cells
    Ameeta Kelekar; Fiscal Year: 2013
    ....
  13. Rocky Mountain Regional Center of Excellence or Biodefense and Emerging Infectiou
    John T Belisle; Fiscal Year: 2013
    ..abstract_text> ..
  14. Involvement of astrocytic two-pore domain K+ channels in ischemic pathology
    Min Zhou; Fiscal Year: 2013
    ....