Endothelial mesenchymal transition in Fuchs corneal dystrophy
Authors: Anas Abu-Dieh 1, Ange Tchatchouang1, Mathieu Thériault2, Isabelle Brunette3, Patrick J. Rochette1, Stéphanie Proulx1. 1Université Laval, Faculty of medicine, Department of ophthalmology, Quebec, QC, Canada; CHU de Quebec-Université Laval Research center, division of regenerative medicine, Quebec, QC, Canada ; LOEX research center, Quebec, QC, Canada., 2CHU de Quebec-Université Laval research center, division of Infectious and immune diseases, Quebec, QC, Canada., 3Maisonneuve-Rosemont Hospital research center, Montreal, QC, Canada.
Author Disclosures: A. Abu-Dieh: None. A. Tchatchouang: None. M. Thériault: None. I. Brunette: None. P.J. Rochette: None. S. Proulx: None.
Abstract Body:
Purpose: Fuchs endothelial corneal dystrophy (FECD) is characterized by an accelerated cell loss, dysfunction of corneal endothelial cells, and abnormal extracellular matrix accumulation resulting in thickening of Descemet’s membrane. Although endothelial-mesenchymal transition (EMT) has been proposed to play a role in FECD pathogenesis, there is no clear evidence that corneal endothelial cells undergo EMT in FECD. The aim of this project is to study the expression of EMT-related proteins in FECD.
Study Design: Basic science
Methods: FECD explants (n=30) were obtained from consenting patients with end-stage clinical FECD undergoing endothelial transplantation, whereas healthy corneas unfit for transplantation in human subjects (n=32) were obtained through our local eye bank (St-Sacrement hospital, Québec). Specimens were fixed (4% paraformaldehyde), permeabilized (0.2% triton X-100), and immunostained against the following EMT markers: S100A4, c-Jun, ZEB-1, LOX, Snail, Slug, β-catenin (β-cat), Active β-catenin (ABC), Smad 2 Phosphorylated (Smad2P), and Smad 3 Phosphorylated (Smad3P). Images were acquired using an upright epifluorescence microscope (Zeiss Z2).
Results: LOX, Slug, β-catenin, Smad2P, and Smad3P had different expression between healthy and FECD specimens. Slug, Smad2P and Smad3P were each expressed in the nuclei of healthy corneal endothelial cells (CECs), whereas they were each expressed in the cytoplasm of FECD CECs. β-cat was expressed near the membrane of healthy CECs, but was expressed in the cytoplasm of FECD cells, near the nucleus. LOX expression was absent in heathy DM and was expressed in the fibrillar membrane of FECD DM, as well as in the cytoplasm of FECD cell. Snail was expressed in the nuclei of both healthy and FECD cells. ABC was expressed in the membrane of both healthy and FECD CECs. ZEB1 was not expressed in either healthy or FECD cells. S100A4 was expressed in the cytoplasm of both healthy and FECD CECs. c-Jun was expressed in the nuclei of healthy cells but absent in FECD cells.
Conclusions: Overall, the results show that only a few of the classic EMT proteins are present in FECD CECs and absent in healthy cells, demonstrating that CECs present a unique EMT-like profile in end-stage FECD. A better understanding of EMT in FECD pathogenesis may enable the development of novel treatment strategies.
