title: Oxidative stress and upregulation of mitochondrial biogenesis genes in mitochondrial DNA-depleted HeLa cells.
abstract: The signaling mechanism through which deficitary mitochondrial function would activate nuclear genes required for mitochondrial biogenesis, has not been established. To explore the hypothesis that reactive oxygen species (ROS), a mitochondrial product, constitute part of the mitochondria-nuclei signaling pathway, we obtained HeLa cells depleted of mitochondrial DNA (rho0 cells) through exposure to ethidium bromide. We found evidences of oxidative stress in rho0 cells, employing a fluorescent probe and measuring NF-kappaB activation. Nuclear Respiratory Factor-1 (NRF-1) and Mitochondrial Transcription Factor A (Tfam) mRNA were measured by RT-PCR. For both transcription factors, rho0 cells revealed significantly higher levels of mRNA. These results support several hypothesis: that endogenous ROS enhance the expression of nuclear mitochondrial biogenesis genes NRF-1 and Tfam; that DNA deprived mitochondria lead to cellular oxidative stress, probably because of incomplete biogenesis of the mitochondrial electron transport chain, and consequently, that ROS are part of a mitochondria-nuclei regulatory signaling pathway.
authors.affiliation: Departamento de Biología Celular y Molecular, Pontificia Universidad Católica de Chile, Casilla, Santiago, 114-D, Chile.
authors.forename: S
authors.initials: S
authors.lastname: Miranda
authors.forename: R
authors.initials: R
authors.lastname: Foncea
authors.forename: J
authors.initials: J
authors.lastname: Guerrero
authors.forename: F
authors.initials: F
authors.lastname: Leighton
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D051265:NF-E2-Related Factor 1; D051266:Nuclear Respiratory Factor 1; D051264:Nuclear Respiratory Factors; D018384:Oxidative Stress; D017382:Reactive Oxygen Species; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics*; D015854:Up-Regulation; D029867:Xenopus Proteins
chemical_list: D017931:DNA Primers; D004272:DNA, Mitochondrial; D004268:DNA-Binding Proteins; D051265:NF-E2-Related Factor 1; C495633:NRF1 protein, human; D051266:Nuclear Respiratory Factor 1; D051264:Nuclear Respiratory Factors; D017382:Reactive Oxygen Species; D015534:Trans-Activators; C097078:XL-MTTFA protein, Xenopus; D029867:Xenopus Proteins