Fuchs endothelial corneal dystrophy (FECD) is the most common and clinically relevant inherited corneal disease in the US population and the third leading cause of corneal transplants in 2007. FECD results from chronic loss of corneal endothelial cells which line the inner surface of the cornea and maintain physiologic hydration necessary for corneal clarity. In some cases, FECD is caused by missense mutations in the alpha 2 collagen VIII (COL8A2) gene. Very little is known about the pathogenesis of FECD due to the fact that only end stage corneas obtained at corneal transplant are available for study. Limited work indicates that apoptosis is occurring in endothelial cells from advanced FECD corneas, although the mechanisms leading to apoptosis are poorly understood. Thus, animal and cell culture models would be invaluable tools to elucidate early events leading to endothelial cell apoptosis in FECD. Our preliminary work includes: 1) identification of markers for the unfolded protein response (UPR) in the endothelium of FECD patient corneas. Proper protein folding is critical for normal function of the cell. The UPR is a highly conserved, broad ranging cellular response induced by an excess of misfolded proteins. Initially, the UPR functions to relieve stress of unfolded proteins through selective alterations in transcription and translation. If protein folding demand and capacity remain unbalanced, the UPR induces cells to undergo apoptosis. In addition, 2) we have developed two gene targeted knock-in mouse lines with different COL8A2 mutations known to cause FECD in humans. Preliminary results show pathologic changes in the basement membrane of the corneal endothelium which are highly similar to those seen in human FECD corneas. The overall hypothesis of this application is that """"""""corneal endothelial cell expression of COL8A2 mutations activates the unfolded protein response and results in endothelial cell death."""""""" The availability of COL8A2 FECD knock-in mice with a relevant pathologic phenotype provides an invaluable opportunity to test this hypothesis as follows:
Aim 1 will assess COL8A2 mutant mice for corneal endothelial cell apoptosis and will characterize in greater detail pathologic changes in corneal endothelium and the endothelial basement membrane comparable to human FECD corneas.
Aim 2 will assess for UPR activation in corneas and cultured corneal endothelial cell lines from COL8A2 mutant mice.
Aim 3 will assess for synergistic effects of UV light (a known inducer of the UPR and environmental stressor for the corneal endothelium) on UPR activation in corneas and cultured corneal endothelial cell lines from COL8A2 mutant mice. This proposal seeks to use COL8A2 FECD mutant mice and corneal endothelial cell lines to establish a novel mechanistic link between the UPR, a major cell stress pathway, and corneal endothelial cell apoptosis resulting from FECD mutations in COL8A2. The establishment of such a link would represent a major advance in the National Eye Institute's goals of improving knowledge and treatment of inherited corneal diseases.

Public Health Relevance

Fuchs endothelial corneal dystrophy (FECD) is a common disease which causes loss of vision from decreased corneal clarity due to death of corneal endothelial cells lining the inner layer of the cornea (Borboli 2002). FECD affects approximately 0.6% of the US population (Krachmer 1978) and is the third leading cause of corneal transplant surgery in the US (Van Meter 2007). The purpose of this study is to investigate the role of the unfolded protein response, a major cell stress pathway, in causing endothelial cell death in FECD.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY019874-02
Application #
8123246
Study Section
Anterior Eye Disease Study Section (AED)
Program Officer
Mckie, George Ann
Project Start
2010-09-01
Project End
2015-08-31
Budget Start
2011-09-01
Budget End
2012-08-31
Support Year
2
Fiscal Year
2011
Total Cost
$393,600
Indirect Cost
Name
Johns Hopkins University
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Kim, Eun Chul; Toyono, Tetsuya; Berlinicke, Cynthia A et al. (2017) Screening and Characterization of Drugs That Protect Corneal Endothelial Cells Against Unfolded Protein Response and Oxidative Stress. Invest Ophthalmol Vis Sci 58:892-900
Toyono, Tetsuya; Usui, Tomohiko; Villarreal Jr, Guadalupe et al. (2016) MicroRNA-29b Overexpression Decreases Extracellular Matrix mRNA and Protein Production in Human Corneal Endothelial Cells. Cornea 35:1466-1470
Losick, Vicki P; Jun, Albert S; Spradling, Allan C (2016) Wound-Induced Polyploidization: Regulation by Hippo and JNK Signaling and Conservation in Mammals. PLoS One 11:e0151251
Vianna, Lucas M M; Stoeger, Christopher G; Galloway, Joshua D et al. (2015) Risk factors for eye bank preparation failure of Descemet membrane endothelial keratoplasty tissue. Am J Ophthalmol 159:829-34.e2
Matthaei, Mario; Zhu, Angela Y; Kallay, Laura et al. (2014) Transcript profile of cellular senescence-related genes in Fuchs endothelial corneal dystrophy. Exp Eye Res 129:13-7
Kim, Eun Chul; Meng, Huan; Jun, Albert S (2014) N-Acetylcysteine increases corneal endothelial cell survival in a mouse model of Fuchs endothelial corneal dystrophy. Exp Eye Res 127:20-5
Son, Hyeck-Soo; Villarreal Jr, Guadalupe; Meng, Huan et al. (2014) On the origin of 'guttae'. Br J Ophthalmol 98:1308-10
Gattey, Devin; Zhu, Angela Y; Stagner, Anna et al. (2014) Fuchs endothelial corneal dystrophy in patients with myotonic dystrophy: a case series. Cornea 33:96-8
Matthaei, Mario; Hu, Jianfei; Kallay, Laura et al. (2014) Endothelial cell microRNA expression in human late-onset Fuchs' dystrophy. Invest Ophthalmol Vis Sci 55:216-25
Matthaei, Mario; Hu, Jianfei; Meng, Huan et al. (2013) Endothelial cell whole genome expression analysis in a mouse model of early-onset Fuchs' endothelial corneal dystrophy. Invest Ophthalmol Vis Sci 54:1931-40

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