title: An altered redox balance and increased genetic instability characterize primary fibroblasts derived from xeroderma pigmentosum group A patients.
abstract: Xeroderma pigmentosum (XP)-A patients are characterized by increased solar skin carcinogenesis and present also neurodegeneration. XPA deficiency is associated with defective nucleotide excision repair (NER) and increased basal levels of oxidatively induced DNA damage. In this study we search for the origin of increased levels of oxidatively generated DNA lesions in XP-A cell genome and then address the question of whether increased oxidative stress might drive genetic instability. We show that XP-A human primary fibroblasts present increased levels and different types of intracellular reactive oxygen species (ROS) as compared to normal fibroblasts, with O₂₋• and H₂O₂ being the major reactive species. Moreover, XP-A cells are characterized by decreased reduced glutathione (GSH)/oxidized glutathione (GSSG) ratios as compared to normal fibroblasts. The significant increase of ROS levels and the alteration of the glutathione redox state following silencing of XPA confirmed the causal relationship between a functional XPA and the control of redox balance. Proton nuclear magnetic resonance (¹H NMR) analysis of the metabolic profile revealed a more glycolytic metabolism and higher ATP levels in XP-A than in normal primary fibroblasts. This perturbation of bioenergetics is associated with different morphology and response of mitochondria to targeted toxicants. In line with cancer susceptibility, XP-A primary fibroblasts showed increased spontaneous micronuclei (MN) frequency, a hallmark of cancer risk. The increased MN frequency was not affected by inhibition of ROS to normal levels by N-acetyl-L-cysteine.
authors.affiliation: Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Parlanti
authors.affiliation: Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Donatella
authors.initials: D
authors.lastname: Pietraforte
authors.affiliation: Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Egidio
authors.initials: E
authors.lastname: Iorio
authors.affiliation: Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Visentin
authors.affiliation: Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: De Nuccio
authors.affiliation: Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Zijno
authors.affiliation: Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Mariarosaria
authors.initials: M
authors.lastname: D'Errico
authors.affiliation: Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Simonelli
authors.affiliation: Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Sanchez
authors.affiliation: Department of Technology and Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Fattibene
authors.affiliation: National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Falchi
authors.affiliation: Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy. Electronic address: dogliotti@iss.it.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Dogliotti
mesh_terms: D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D053078:Membrane Potential, Mitochondrial; D048629:Micronuclei, Chromosome-Defective; D015162:Micronucleus Tests; D008928:Mitochondria / Q000473:pathology; D018384:Oxidative Stress / Q000235:genetics; D061251:Primary Cell Culture; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014983:Xeroderma Pigmentosum / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D051760:Xeroderma Pigmentosum Group A Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D051760:Xeroderma Pigmentosum Group A Protein; D005978:Glutathione
keywords: DNA repair; Oxidatively generated damage; metabolism; micronuclei; mitochondria