title: Silencing of frataxin gene expression triggers p53-dependent apoptosis in human neuron-like cells.
abstract: Friedreich's ataxia (FRDA) is an autosomal recessive disease caused by mutations that produce a deficiency in frataxin. Despite the importance of neurodegeneration in FRDA, little is known about the consequences of frataxin deficiency in neuronal cells. Here we describe a neuronal cell model for FRDA based on the use of lentiviral vectors that carry minigenes encoding frataxin-specific shRNAs that silence the expression of this gene. These lentivectors can knockdown frataxin expression in human neuroblastoma SH-SY5Y cells, which results in large-scale cell death in differentiated neuron-like cells but not in undifferentiated neuroblastoma cells. Frataxin-deficient neuron-like cells appear to die through apoptosis that is accompanied by up-regulation of p53, PUMA and Bax and activation of caspase-3. No significant autophagy is observed in frataxin-deficient neuron-like cells and the pharmacological activation of autophagy does not significantly increase neuronal cell death in response to the frataxin deficiency. Cell death triggered by frataxin knockdown can be impaired by interference with p53, caspase inhibitors and gene transfer of FXN. These results suggest that frataxin gene silencing in human neuron-like cells may constitute a useful cell model to characterize the molecular changes triggered by frataxin deficiency in neurons, as well as to search for therapies that may protect against neurodegeneration.
authors.affiliation: Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa (UAM-CSIC), C/NicolásCabrera 1, Campus de Cantoblanco, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Gloria M
authors.initials: GM
authors.lastname: Palomo
authors.forename: Toñi
authors.initials: T
authors.lastname: Cerrato
authors.forename: Ricardo
authors.initials: R
authors.lastname: Gargini
authors.forename: Javier
authors.initials: J
authors.lastname: Diaz-Nido
mesh_terms: D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D005621:Friedreich Ataxia / Q000235:genetics / Q000378:metabolism / Q000628:therapy; D020868:Gene Silencing; D006801:Humans; D033862:Iron-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D008954:Models, Biological; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism; D000096923:Frataxin
chemical_list: D051017:Apoptosis Regulatory Proteins; D053148:Caspase 3; D033862:Iron-Binding Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D000096923:Frataxin; C494826:BAX protein, human; C438378:BBC3 protein, human; C495901:TP53 protein, human; C505407:CASP3 protein, human