title: 2-Phenyl-APB-144-Induced Retinal Pigment Epithelium Degeneration and Its Underlying Mechanisms.
abstract: OBJECTIVE
  To investigate the efficacy of 2-phenyl-APB-144 (APB)-induced retinopathy in a rat model and its underlying mechanisms, with a particular focus on retinal pigment epithelium (RPE) degeneration.
  
  
  METHODS
  Electroretinograms (ERGs) were evaluated in APB-administered rats. In ARPE-19 cells, cathepsin, and autophagy marker LC3 were analyzed by western blotting or immunohistochemistry. Organelle pH alterations were detected by Acridine Orange Staining. Endoplasmic reticulum stress-dependent or -independent cell death signaling was analyzed by reporter gene assays of activating transcription factor 4 (ATF4), immunoglobulin heavy-chain binding protein (BiP), inositol-requiring enzyme 1α (IRE1α), quantitative reverse transcription-polymerase chain reaction of CHOP mRNA, and the effects of pharmacological eukaryotic initiation factor 2α (eIF2α) dephosphorylation inhibitor, Salubrinal. The pharmacological effects of Salubrinal were examined by fluorophotometry, electrophysiology, and histopathology.
  
  
  RESULTS
  APB-induced ERG amplitude reduction and fluorescein permeability enhancement into the vitreous body of rats were determined. In ARPE-19 cells, APB-induced organelle pH alterations, imbalances of procathepsin and cathepsin expression, the time-dependent accumulation of LC3-II, and the translational activation of ATF4 were determined. Salubrinal protected against APB-induced cell death and inhibited ATF4 downstream factor CHOP mRNA induction. In APB-induced rat retinopathy, systemic Salubrinal alleviated the enhanced fluorescein permeability into the vitreous body from the RPE, the reductions in ERG amplitudes, and RPE degeneration.
  
  
  CONCLUSIONS
  Organelle pH alterations and autophagy impairments are involved in APB-induced RPE cell death. Inhibition of eIF2α dephosphorylation protected the RPE in vivo and in vitro. These findings suggested that APB-induced retinopathy is a valuable animal model for exploring the mechanism of RPE-driven retinopathy.
authors: 1 Nara Research and Development Center, Santen Pharmaceutical Co. Ltd. , Ikoma, Nara, Japan .|2 Laboratory of Molecular and Cell Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology , Ikoma, Nara, Japan .
authors: Shin-ichiro
authors: S
authors: Hirai
authors: 1 Nara Research and Development Center, Santen Pharmaceutical Co. Ltd. , Ikoma, Nara, Japan .|2 Laboratory of Molecular and Cell Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology , Ikoma, Nara, Japan .
authors: Hiroaki
authors: H
authors: Kurashima
authors: 2 Laboratory of Molecular and Cell Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology , Ikoma, Nara, Japan .
authors: Daisuke
authors: D
authors: Nakamura
authors: 2 Laboratory of Molecular and Cell Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology , Ikoma, Nara, Japan .
authors: Tomoko
authors: T
authors: Komatsu
authors: 2 Laboratory of Molecular and Cell Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology , Ikoma, Nara, Japan .
authors: Yuki
authors: Y
authors: Yasuda
authors: 1 Nara Research and Development Center, Santen Pharmaceutical Co. Ltd. , Ikoma, Nara, Japan .
authors: Sayo
authors: S
authors: Habashita-Obata
authors: 1 Nara Research and Development Center, Santen Pharmaceutical Co. Ltd. , Ikoma, Nara, Japan .
authors: Sanae
authors: S
authors: Ichikawa
authors: 1 Nara Research and Development Center, Santen Pharmaceutical Co. Ltd. , Ikoma, Nara, Japan .
authors: Osamu
authors: O
authors: Katsuta
authors: 3 Advanced Scientific Research Leaders Development Unit, Gunma University , Maebashi, Gunma, Japan .
authors: Takao
authors: T
authors: Iwawaki
authors: 2 Laboratory of Molecular and Cell Genetics, Graduate School of Biological Sciences, Nara Institute of Science and Technology , Ikoma, Nara, Japan .
authors: Kenji
authors: K
authors: Kohno
mesh_terms: D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D001713:Biphenyl Compounds / Q000633:toxicity*; D015153:Blotting, Western; D002403:Cathepsins / Q000378:metabolism; D002460:Cell Line; D002934:Cinnamates / Q000494:pharmacology; D004195:Disease Models, Animal; D004596:Electroretinography; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D015388:Organelles / Q000737:chemistry; D051381:Rats; D011914:Rats, Inbred BN; D012164:Retinal Diseases / Q000139:chemically induced* / Q000473:pathology; D055213:Retinal Pigment Epithelium / Q000187:drug effects* / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D001713:Biphenyl Compounds; D002403:Cathepsins; D002934:Cinnamates; D008869:Microtubule-Associated Proteins; D013890:Thiourea; C526109:Anxa3 protein, rat; C496827:salubrinal; C064427:1,4-bis(4-aminophenoxy)-2-phenylbenzene