Involvement of mitochondrial K+ release and cellular efflux in ischemic and apoptotic neuronal death

Dong Liu, John R. Slevin, Chengbiao Lu, Sic L. Chan, Magnus Hansson, Eskil Elmér, Mark P. Mattson

Research output: Contribution to journalArticle

Abstract

We measured and manipulated intracellular potassium (K+) fluxes in cultured hippocampal neurons in an effort to understand the involvement of K+ in neuronal death under conditions of ischemia and exposure to apoptotic stimuli Measurements of the intracellular K+ concentration using the fluorescent probe 1,3-benzenedicarboxylic acid, 4,4′-[1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7, 16-diyl-bis(5-methoxy-6,2-benzofurandiyl)]bis-, tetrakis [(acetyloxy) methyl] ester (PBFI) revealed that exposure of neurons to cyanide (chemical hypoxia), glutamate (excitotoxic insult) or staurosporine (apoptotic stimulus) results in efflux of K+ and cell death. Treatment of neurons with 5-hydroxydecanoate (5HD), an inhibitor of mitochondrial K+ channels, reduced K+ fluxes in neurons exposed to each insult and increased the resistance of the cells to death. K+ efflux was attenuated, levels of oxyradicals were decreased, mitochondrial membrane potential was stabilized and release of cytochrome c from mitochondria was 3 attenuated in neurons treated with 5HD. K+ was rapidly released into the cytosol from mitochondria when neurons were exposed to the K+ channel opener, diazoxide, or to the mitochondrial uncoupler, carbonyl cyanide 4(trifluoromethoxy)-phenylhydrazone (FCCP), demonstrating that the intramitochondrial K+ concentration is greater than the cytosolic K+ concentration. The release of K+ from mitochondria was followed by efflux through plasma membrane K+ channels. In vivo studies showed that 5HD reduces ischemic brain damage without affecting cerebral blood flow in a mouse model of focal ischemic stroke. These findings suggest that intracellular K+ fluxes play a key role in modulating neuronal oxyradical production and cell survival under ischemic conditions, and that agents that modify K+ fluxes may have therapeutic benefit in stroke and related neurodegenerative conditions.

Original languageEnglish (US)
Pages (from-to)966-979
Number of pages14
JournalJournal of Neurochemistry
Volume86
Issue number4
DOIs
StatePublished - Aug 2003

Fingerprint

Neurons
Mitochondria
Fluxes
Cerebrovascular Circulation
Cell Death
Stroke
Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone
Diazoxide
Staurosporine
Mitochondrial Membrane Potential
Cyanides
Cell death
Cell membranes
Cytochromes c
Ion Channels
Fluorescent Dyes
Cytosol
Glutamic Acid
Brain
Cell Survival

Keywords

  • Apoptosis
  • Cytochrome c
  • Glutamate
  • Hippocampus
  • Hypoxia
  • Pre-conditioning

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

Involvement of mitochondrial K+ release and cellular efflux in ischemic and apoptotic neuronal death. / Liu, Dong; Slevin, John R.; Lu, Chengbiao; Chan, Sic L.; Hansson, Magnus; Elmér, Eskil; Mattson, Mark P.

In: Journal of Neurochemistry, Vol. 86, No. 4, 08.2003, p. 966-979.

Research output: Contribution to journalArticle

Liu, Dong ; Slevin, John R. ; Lu, Chengbiao ; Chan, Sic L. ; Hansson, Magnus ; Elmér, Eskil ; Mattson, Mark P. / Involvement of mitochondrial K+ release and cellular efflux in ischemic and apoptotic neuronal death. In: Journal of Neurochemistry. 2003 ; Vol. 86, No. 4. pp. 966-979.
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AU - Liu, Dong

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AU - Lu, Chengbiao

AU - Chan, Sic L.

AU - Hansson, Magnus

AU - Elmér, Eskil

AU - Mattson, Mark P.

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N2 - We measured and manipulated intracellular potassium (K+) fluxes in cultured hippocampal neurons in an effort to understand the involvement of K+ in neuronal death under conditions of ischemia and exposure to apoptotic stimuli Measurements of the intracellular K+ concentration using the fluorescent probe 1,3-benzenedicarboxylic acid, 4,4′-[1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7, 16-diyl-bis(5-methoxy-6,2-benzofurandiyl)]bis-, tetrakis [(acetyloxy) methyl] ester (PBFI) revealed that exposure of neurons to cyanide (chemical hypoxia), glutamate (excitotoxic insult) or staurosporine (apoptotic stimulus) results in efflux of K+ and cell death. Treatment of neurons with 5-hydroxydecanoate (5HD), an inhibitor of mitochondrial K+ channels, reduced K+ fluxes in neurons exposed to each insult and increased the resistance of the cells to death. K+ efflux was attenuated, levels of oxyradicals were decreased, mitochondrial membrane potential was stabilized and release of cytochrome c from mitochondria was 3 attenuated in neurons treated with 5HD. K+ was rapidly released into the cytosol from mitochondria when neurons were exposed to the K+ channel opener, diazoxide, or to the mitochondrial uncoupler, carbonyl cyanide 4(trifluoromethoxy)-phenylhydrazone (FCCP), demonstrating that the intramitochondrial K+ concentration is greater than the cytosolic K+ concentration. The release of K+ from mitochondria was followed by efflux through plasma membrane K+ channels. In vivo studies showed that 5HD reduces ischemic brain damage without affecting cerebral blood flow in a mouse model of focal ischemic stroke. These findings suggest that intracellular K+ fluxes play a key role in modulating neuronal oxyradical production and cell survival under ischemic conditions, and that agents that modify K+ fluxes may have therapeutic benefit in stroke and related neurodegenerative conditions.

AB - We measured and manipulated intracellular potassium (K+) fluxes in cultured hippocampal neurons in an effort to understand the involvement of K+ in neuronal death under conditions of ischemia and exposure to apoptotic stimuli Measurements of the intracellular K+ concentration using the fluorescent probe 1,3-benzenedicarboxylic acid, 4,4′-[1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7, 16-diyl-bis(5-methoxy-6,2-benzofurandiyl)]bis-, tetrakis [(acetyloxy) methyl] ester (PBFI) revealed that exposure of neurons to cyanide (chemical hypoxia), glutamate (excitotoxic insult) or staurosporine (apoptotic stimulus) results in efflux of K+ and cell death. Treatment of neurons with 5-hydroxydecanoate (5HD), an inhibitor of mitochondrial K+ channels, reduced K+ fluxes in neurons exposed to each insult and increased the resistance of the cells to death. K+ efflux was attenuated, levels of oxyradicals were decreased, mitochondrial membrane potential was stabilized and release of cytochrome c from mitochondria was 3 attenuated in neurons treated with 5HD. K+ was rapidly released into the cytosol from mitochondria when neurons were exposed to the K+ channel opener, diazoxide, or to the mitochondrial uncoupler, carbonyl cyanide 4(trifluoromethoxy)-phenylhydrazone (FCCP), demonstrating that the intramitochondrial K+ concentration is greater than the cytosolic K+ concentration. The release of K+ from mitochondria was followed by efflux through plasma membrane K+ channels. In vivo studies showed that 5HD reduces ischemic brain damage without affecting cerebral blood flow in a mouse model of focal ischemic stroke. These findings suggest that intracellular K+ fluxes play a key role in modulating neuronal oxyradical production and cell survival under ischemic conditions, and that agents that modify K+ fluxes may have therapeutic benefit in stroke and related neurodegenerative conditions.

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