title: 4-Acetoxyphenol Prevents RPE Oxidative Stress-Induced Necrosis by Functioning as an NRF2 Stabilizer.
abstract: OBJECTIVE
  Oxidative stress has been suggested to be a major risk factor for the pathogenesis of AMD. Retinal pigment epithelial (RPE) cells are essential for maintaining the homeostasis of the retina, and RPE cell death and the resultant photoreceptor apoptosis have been observed in dry AMD, especially in geographic atrophy. The purpose of this article was to identify and repurpose the Food and Drug Administration-approved natural compound 4-Acetoxyphenol (4-AC), and to evaluate its effect and mechanism in protecting against oxidative stress-induced RPE necrosis.
  
  
  METHODS
  We exposed ARPE-19 cells to tert-Butyl hydroperoxide (tBHP) after pretreatment with 4-AC, and measured cell viability by MTT assay. Aggregation of RIPK3 and HMGB1 nuclear release were analyzed by transfected reporter genes. Reactive oxygen species (ROS) were measured using a commercially available ROS detection system. The importance of the NRF2/NQO1/HO-1 pathway in mediating 4-AC function was corroborated by siRNA studies, qRT-PCR, and immunostaining.
  
  
  RESULTS
  We have identified a natural antioxidant, 4-AC, which demonstrates strong abilities to protect RPE cells from oxidative stress-induced necrosis. Mechanistically, 4-AC blocked the increase of cellular ROS induced by oxidative stress, and upregulated NQO1 and HO-1 genes by stabilizing and inducing the nuclear translocation of NRF2 transcription factor. The NQO1, HO-1, and NRF2 were further shown to be required for 4-AC protection of RPE cells from death induced by tBHP. The tBHQ, an NRF2 stabilizer, consistently mimicked the protective effect of 4-AC against tBHP-induced RPE death.
  
  
  CONCLUSIONS
  The compound 4-AC protects ARPE-19 cells from oxidative stress-induced necrosis through upregulation of NQO1 and HO-1 genes by stabilization of NRF2.
authors.affiliation: Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana, United States.
authors.forename: Jakub
authors.initials: J
authors.lastname: Hanus
authors.affiliation: Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana, United States.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kolkin
authors.affiliation: Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana, United States.
authors.forename: Julia
authors.initials: J
authors.lastname: Chimienti
authors.affiliation: Southern Eye Bank, Metairie, Louisiana, United States.
authors.forename: Sara
authors.initials: S
authors.lastname: Botsay
authors.affiliation: Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana, United States 3Department of Ophthalmology, Tulane University, New Orleans, Louisiana, United States.
authors.forename: Shusheng
authors.initials: S
authors.lastname: Wang
mesh_terms: D017209:Apoptosis; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D009336:Necrosis; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D020122:tert-Butylhydroperoxide / Q000494:pharmacology*
chemical_list: D051267:NF-E2-Related Factor 2; D017382:Reactive Oxygen Species; D020122:tert-Butylhydroperoxide