title: Lithium treatment increases endothelial cell survival and autophagy in a mouse model of Fuchs endothelial corneal dystrophy.
abstract: BACKGROUND
  Lithium previously has been shown to reduce both endoplasmic reticulum (ER) and oxidative stress in other in vitro and in vivo model systems. We investigated lithium's effects on cultured corneal endothelial cells (CECs) exposed to these types of stress and in a mouse model of Fuchs endothelial corneal dystrophy (FECD).
  
  
  METHODS
  Viability of cultured bovine CECs was determined by CellTiter-Glo. 2-month-old Col8a2(Q455K/Q455K) mutant (Q455K) and C57/Bl6 wild type animals were divided into two groups of 15 mice. Group I received 0.2% lithium carbonate-containing chow and Group II received control chow for 7 months. Confocal microscopy, transmission electron microscopy, real-time PCR (RT-PCR) and western blot were performed.
  
  
  RESULTS
  Pretreatment with lithium increased viability of cultured CECs after H2O2 and thapsigargin exposure compared with untreated controls (p<0.05). In vivo analysis of mouse corneal endothelium showed the following: endothelial cell density of lithium treated Q455K was higher than for untreated Q455K (p<0.01). transmission electron microscopy of lithium treated Q455K showed normal endothelium with enlarged autophagosomes, but untreated Q455K showed dilated ER and guttae. Compared with untreated Q455K endothelium, lithium treated Q455K showed significant upregulation of P62, Tmem74, Tm9sf1 and Tmem166 by RT-PCR and of Atg5-12 conjugate by western blotting indicating that lithium treatment increased autophagy. Although RT-PCR unexpectedly showed increased levels of lithium response genes, caspase 12, Gsk3β, Arrβ2 and Impa1, western blotting showed the expected downregulation of Arrβ2 and Impa1 proteins in response to lithium treatment.
  
  
  CONCLUSIONS
  Lithium increases cultured CEC survival against ER and oxidative stress. Increased autophagy in lithium treated endothelium in a mouse model of FECD suggests autophagy may contribute to increased endothelial cell survival.
authors.affiliation: Cornea and Anterior Segment Division, Wilmer Eye Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland 21231, USA.
authors.forename: Eun Chul
authors.initials: EC
authors.lastname: Kim
authors.forename: Huan
authors.initials: H
authors.lastname: Meng
authors.forename: Albert S
authors.initials: AS
authors.lastname: Jun
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002417:Cattle; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004195:Disease Models, Animal; D000091342:Endoplasmic Reticulum Chaperone BiP; D004728:Endothelium, Corneal / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005642:Fuchs' Endothelial Dystrophy / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control*; D005786:Gene Expression Regulation / Q000502:physiology; D006360:Heat-Shock Proteins / Q000235:genetics; D006861:Hydrogen Peroxide / Q000633:toxicity; D016651:Lithium Carbonate / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D018384:Oxidative Stress; D060888:Real-Time Polymerase Chain Reaction; D019284:Thapsigargin / Q000633:toxicity; D051742:Transcription Factor CHOP / Q000235:genetics
chemical_list: C497250:Ddit3 protein, mouse; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; D051742:Transcription Factor CHOP; D016651:Lithium Carbonate; D019284:Thapsigargin; D006861:Hydrogen Peroxide
keywords: Cornea; Drugs