title: Mitochondrial-dependent apoptosis in Huntington's disease human cybrids.
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.
authors.affiliation: Center for Neuroscience and Cell Biology, Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal.
authors.forename: Ildete L
authors.initials: IL
authors.lastname: Ferreira
authors.forename: Maria V
authors.initials: MV
authors.lastname: Nascimento
authors.forename: Márcio
authors.initials: M
authors.lastname: Ribeiro
authors.forename: Sandra
authors.initials: S
authors.lastname: Almeida
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Cardoso
authors.forename: Manuela
authors.initials: M
authors.lastname: Grazina
authors.forename: João
authors.initials: J
authors.lastname: Pratas
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Santos
authors.forename: Cristina
authors.initials: C
authors.lastname: Januário
authors.forename: Catarina R
authors.initials: CR
authors.lastname: Oliveira
authors.forename: A Cristina
authors.initials: AC
authors.lastname: Rego
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D000072224:Bcl-2-Like Protein 11; D016022:Case-Control Studies; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D014450:Electron Transport Complex III / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D006801:Humans; D006816:Huntington Disease / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology*; D007424:Intracellular Fluid / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D008565:Membrane Proteins / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism*; D009579:Nitrobenzoates / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D013347:Subcellular Fractions / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D018243:Teratocarcinoma; D013997:Time Factors; D019680:Trinucleotide Repeat Expansion / Q000235:genetics; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D051033:Apoptosis Inducing Factor; D051017:Apoptosis Regulatory Proteins; C000606775:BCL2L11 protein, human; D000072224:Bcl-2-Like Protein 11; D004272:DNA, Mitochondrial; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D009097:Multienzyme Complexes; D009579:Nitrobenzoates; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D013481:Superoxides; D007770:L-Lactate Dehydrogenase; D003576:Electron Transport Complex IV; D002950:Citrate (si)-Synthase; D053148:Caspase 3; D014450:Electron Transport Complex III; C040770:3-nitrobenzoic acid; D019311:Staurosporine