Abstract
We investigated the involvement of mitochondrial-dependent apoptosis in Huntington's disease (HD) vs. control (CTR) cybrids, obtained from the fusion of human platelets with mitochondrial DNA-depleted NT2 cells, and further exposed to 3-nitropropionic acid (3-NP) or staurosporine (STS). Untreated HD cybrids did not exhibit significant modifications in the activity of mitochondrial respiratory chain complexes I-IV or in mtDNA sequence variations suggestive of a primary role in mitochondrial susceptibility in the subpopulation of HD carriers studied. However, a slight decrease in mitochondrial membrane potential and increased formation of intracellular hydroperoxides was observed in HD cybrids under basal conditions. Furthermore, apoptotic nuclei morphology and a moderate increase in caspase-3 activation, as well as increased levels of superoxide ions and hydroperoxides were observed in HD cybrids upon 3-NP or STS treatment. 3-NP-evoked apoptosis in HD cybrids involved cytochrome c and AIF release from mitochondria, which was associated with mitochondrial Bax translocation. CTR cybrids subjected to 3-NP showed increased mitochondrial Bax and Bim levels and the release of AIF, but not cytochrome c, suggesting a different mode of cell death, linked to the loss of membrane integrity. Additionally, increased mitochondrial Bim and Bak levels, and a slight release of cytochrome c in untreated HD cybrids may help to explain their moderate susceptibility to mitochondrial-dependent apoptosis.
Copyright 2010 Elsevier Inc. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adult
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Analysis of Variance
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Apoptosis / drug effects
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Apoptosis / physiology*
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Apoptosis Inducing Factor / metabolism
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Apoptosis Regulatory Proteins / metabolism
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Bcl-2-Like Protein 11
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Case-Control Studies
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Caspase 3 / metabolism
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Cell Line, Tumor
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Citrate (si)-Synthase / metabolism
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DNA, Mitochondrial / metabolism
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Dose-Response Relationship, Drug
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Electron Transport Complex III / metabolism
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Electron Transport Complex IV / metabolism
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Enzyme Inhibitors / pharmacology
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Gene Expression Regulation / drug effects
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Gene Expression Regulation / genetics
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Humans
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Huntington Disease / genetics
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Huntington Disease / pathology*
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Huntington Disease / physiopathology*
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Intracellular Fluid / metabolism
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L-Lactate Dehydrogenase / metabolism
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Membrane Potential, Mitochondrial / drug effects
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Membrane Potential, Mitochondrial / genetics
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Membrane Potential, Mitochondrial / physiology
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Membrane Proteins / metabolism
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Mitochondria / drug effects
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Mitochondria / metabolism*
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Multienzyme Complexes / metabolism*
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Nitrobenzoates / pharmacology
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-bcl-2 / metabolism
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Reactive Oxygen Species / metabolism
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Staurosporine / pharmacology
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Subcellular Fractions / metabolism
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Superoxides / metabolism
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Teratocarcinoma
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Time Factors
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Trinucleotide Repeat Expansion / genetics
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bcl-2 Homologous Antagonist-Killer Protein / metabolism
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bcl-2-Associated X Protein / metabolism
Substances
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Apoptosis Inducing Factor
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Apoptosis Regulatory Proteins
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BCL2L11 protein, human
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Bcl-2-Like Protein 11
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DNA, Mitochondrial
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Enzyme Inhibitors
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Membrane Proteins
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Multienzyme Complexes
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Nitrobenzoates
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-bcl-2
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Reactive Oxygen Species
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bcl-2 Homologous Antagonist-Killer Protein
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bcl-2-Associated X Protein
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Superoxides
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L-Lactate Dehydrogenase
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Electron Transport Complex IV
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Citrate (si)-Synthase
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Caspase 3
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Electron Transport Complex III
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3-nitrobenzoic acid
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Staurosporine