title: Ischemia-reperfusion injury of the retina is linked to necroptosis via the ERK1/2-RIP3 pathway.
abstract: OBJECTIVE
  Ischemia-reperfusion (IR) injury is involved in the pathology of many retinal disorders since it contributes to the death of retinal neurons and the subsequent decline in vision. We determined the molecular patterns of some of the principal molecules involved in necroptosis and investigated whether IR retinal injury is associated with the extracellular signal-regulated kinase-1/2- receptor-interacting protein kinase 3 (ERK1/2-RIP3) pathway.
  
  
  METHODS
  The cellular and subcellular localization of molecules involved in the cell death pathway, including RAGE, ERK1/2, FLIP, and RIP3, was determined with immunohistochemistry of cryosections of IR-injured retina from 2-month-old Long Evans rats. The total and phosphorylated protein levels were analyzed with quantitative western blots. ERK1/2 activity was inhibited by intravitreal injection of U0126, a highly selective inhibitor of mitogen-activated protein kinase 1/2 (MEK1/2).
  
  
  RESULTS
  The IR-injured rat retinas expressed two RAGE isoforms with different intracellular localizations at early time points after injury. At that time point, frame inhibition of ERK activation decreased RIP3 accumulation and cell death. FLIP was detected in the IR-injured rat retinas at early time points after ischemia reperfusion.
  
  
  CONCLUSIONS
  We report that the necroptotic cell death mechanism is executed by an ERK1/2-RIP3 pathway in the retinal ganglion cells in early stages after IR injury. Inhibition of ERK1/2 activity increased retinal ganglion cell (RGC) survival indicating that targeting of this pathway within the initial 12 h after IR injury can be used to inhibit the necroptosis pathway. We also provide evidence that a novel RAGE isoform is expressed in the early stages in rat retinal RGCs.
authors.affiliation: Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu, China ; Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, KY.
authors.forename: Sheng
authors.initials: S
authors.lastname: Gao
authors.affiliation: Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, KY.
authors.forename: Kalina
authors.initials: K
authors.lastname: Andreeva
authors.affiliation: Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, KY.
authors.forename: Nigel G F
authors.initials: NG
authors.lastname: Cooper
mesh_terms: D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein / Q000235:genetics / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D005260:Female; D005786:Gene Expression Regulation; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics* / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D000067759:Receptor for Advanced Glycation End Products; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D011971:Receptors, Immunologic / Q000235:genetics* / Q000378:metabolism; D015427:Reperfusion Injury / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D012165:Retinal Ganglion Cells / Q000378:metabolism* / Q000473:pathology; D015398:Signal Transduction
chemical_list: D002070:Butadienes; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D009570:Nitriles; D020033:Protein Isoforms; D047428:Protein Kinase Inhibitors; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; C113580:U 0126; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; C582791:Ripk3 protein, rat; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3