Impaired homeostasis and phenotypic abnormalities in Prdx6-/-mice lens epithelial cells by reactive oxygen species: increased expression and activation of TGFbeta.
PRDX6, a member of the peroxiredoxins (PRDXs) family, is a key player in the removal of reactive oxygen species (ROS). Using targeted inactivation of the Prdx6 gene, we present evidence that the corresponding protein offsets the deleterious effects of ROS on lens epithelial cells (LECs) and regulates gene expression by limiting its levels. PRDX6-depleted LECs displayed phenotypic alterations and elevated alpha-smooth muscle actin and betaig-h3 expression (markers for cataractogenesis), indistinguishable from transforming growth factor beta (TGFbeta)-induced changes. Biochemical assays disclosed enhanced levels of ROS, as well as high expression and activation of TGFbeta1 in Prdx6-/- LECs. A CAT assay revealed transcriptional repression of lens epithelium-derived growth factor (LEDGF), HSP27, and alphaB-crystallin promoter activities in these cells. A gel mobility shift assay demonstrated the attenuation of LEDGF binding to heat shock or stress response elements present in these genes. A supply of PRDX6 toPrdx6-/- LECs reversed these changes. Based on the above data, we propose a rheostat role for PRDX6 in regulating gene expression by controlling the ROS level to maintain cellular homeostasis.
Fatma
N
N
Department of Ophthalmology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
Kubo
E
E
Sharma
P
P
Beier
D R
DR
Singh
D P
DP
D000818:Animals; D017209:Apoptosis; D002465:Cell Movement; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000235:genetics; D006706:Homeostasis / Q000187:drug effects*; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D007908:Lens, Crystalline / Q000002:abnormalities* / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D018384:Oxidative Stress / Q000187:drug effects; D010544:Peroxidases / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins; D010641:Phenotype; D017382:Reactive Oxygen Species / Q000494:pharmacology*; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D038203:alpha-Crystallin B Chain / Q000235:genetics
D004268:DNA-Binding Proteins; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486699:Hspb2 protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D017382:Reactive Oxygen Species; D016212:Transforming Growth Factor beta; D038203:alpha-Crystallin B Chain; C119380:lens epithelium-derived growth factor; D004247:DNA; D010544:Peroxidases; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins; C515983:Prdx6 protein, mouse