title: L450W and Q455K Col8a2 knock-in mouse models of Fuchs endothelial corneal dystrophy show distinct phenotypes and evidence for altered autophagy.
abstract: OBJECTIVE
  We compared the cellular phenotypes and studied the role of autophagy in the pathogenesis of Fuchs endothelial corneal dystrophy (FECD) using two α2 collagen VIII (Col8a2) knock-in mouse models and human FECD tissues.
  
  
  METHODS
  In vivo corneal endothelial cell (CEC) counts and morphology were analyzed by clinical confocal microscopy. Ultrastructural analysis of CECs was performed by transmission electron microscopy. Real-time PCR and Western blotting were performed using total RNA, and protein extracted from mouse CECs and human CECs obtained from FECD and autopsy patients.
  
  
  RESULTS
  Both Col8a2 mouse models exhibited hallmarks of FECD; however, the Col8a2(L450W/L450W) mice exhibited a milder phenotype compared to the Col8a2(Q455K/Q455K) mice. Both models exhibited upregulation of the unfolded protein response (UPR) as evidenced by dilated rough endoplasmic reticulum (RER), and upregulation of UPR-associated genes and proteins. Real-time PCR of Col8a2(L450W/L450W) and Col8a2(Q455K/Q455K) CECs at 40 weeks revealed a 2.1-fold (P < 0.05) and a 5.2-fold (P < 0.01) upregulation of the autophagy marker Dram1, respectively. Real-time PCR of human FECD endothelium revealed a 10.4-fold upregulation of DRAM1 (P < 0.0001) compared to autopsy controls.
  
  
  CONCLUSIONS
  The Col8a2(L450W/L450W) and Col8a2(Q455K/Q455K) mouse models of FECD showed distinct endothelial cell phenotypes. Dram1 was associated with activation of the UPR and increased autophagy. Overexpression of this gene in mouse and human FECD endothelial cells suggested a role for altered autophagy in this disease.
authors: Wilmer Eye Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland 21231, USA.
authors: Huan
authors: H
authors: Meng
authors: Mario
authors: M
authors: Matthaei
authors: Narendrakumar
authors: N
authors: Ramanan
authors: Rhonda
authors: R
authors: Grebe
authors: Shukti
authors: S
authors: Chakravarti
authors: Caroline L
authors: CL
authors: Speck
authors: Martha
authors: M
authors: Kimos
authors: Neeraj
authors: N
authors: Vij
authors: Charles G
authors: CG
authors: Eberhart
authors: Albert S
authors: AS
authors: Jun
mesh_terms: D000818:Animals; D001343:Autophagy / Q000235:genetics / Q000502:physiology*; D015153:Blotting, Western; D024102:Collagen Type VIII / Q000235:genetics* / Q000502:physiology; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000473:pathology; D004728:Endothelium, Corneal / Q000378:metabolism; D005642:Fuchs' Endothelial Dystrophy / Q000235:genetics* / Q000473:pathology*; D055879:Gene Knock-In Techniques; D005838:Genotype; D051379:Mice; D008822:Mice, Transgenic; D046529:Microscopy, Electron, Transmission; D010641:Phenotype; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D024102:Collagen Type VIII