title: Apoptosis-related mitochondrial dysfunction defines human monocyte-derived dendritic cells with impaired immuno-stimulatory capacities.
abstract: The death of dendritic cells (DCs) can potentially influence immune responses by affecting the duration of DC stimulation of lymphocytes. Here, we report that cultured mature monocyte-derived DCs manifest early mitochondrial damage (i.e. within 24 hrs), characterized by mitochondrial membrane potential (psi Delta m) disruption and mitochondrial release of pro-apoptotic factors, followed by reactive oxygen species (ROS) production and activation of caspases. Afterwards, DCs with mitochondrial alterations are condemned to undergo apoptosis and necrosis. Macroarray analysis results (validated by real time quantitative-PCR (QRT-PCR) and immunoblotting), showed up-regulation of the pro-apoptotic member of the Bcl-2 family, Bim, while expression of several anti-apoptotic molecules was down-regulated. Importantly, pre-apoptotic DCs (characterized by a low Delta psi m) showed a modified phenotype, with down-regulation of HLA-DR and of the co-stimulatory molecules CD80 and CD86. Moreover, sorted viable low psi Delta m DCs were unable to activate allogeneic T cells, indicating that pre-apoptotic DCs have already lost some of their immuno-stimulatory capabilities long before any detectable signs of death occur. Perturbations to mitochondrial respiration with rotenone identified the same modifications to DC immune functions. These data indicate a strong requirement for mitochondrial integrity for the immuno-stimulatory capacities of DC. Determining Delta psi m could be a useful parameter to select 'fully' functional DCs for anti-tumour vaccines.
authors.affiliation: Inserm U837 and Plate-forme de Biothérapie, Faculté de Médecine Université de Lille II 1, Place Verdun, Lille Cedex, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Castera
authors.forename: Anne Sophie
authors.initials: AS
authors.lastname: Hatzfeld-Charbonnier
authors.forename: Caroline
authors.initials: C
authors.lastname: Ballot
authors.forename: Florence
authors.initials: F
authors.lastname: Charbonnel
authors.forename: Edith
authors.initials: E
authors.lastname: Dhuiege
authors.forename: Thierry
authors.initials: T
authors.lastname: Velu
authors.forename: Pierre
authors.initials: P
authors.lastname: Formstecher
authors.forename: Laurent
authors.initials: L
authors.lastname: Mortier
authors.forename: Philippe
authors.initials: P
authors.lastname: Marchetti
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D020169:Caspases / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000276:immunology*; D004789:Enzyme Activation / Q000187:drug effects; D020869:Gene Expression Profiling; D006801:Humans; D007114:Immunization; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000473:pathology*; D009000:Monocytes / Q000166:cytology* / Q000187:drug effects / Q000276:immunology*; D010641:Phenotype; D012402:Rotenone / Q000494:pharmacology
chemical_list: D012402:Rotenone; D020169:Caspases