New potential markers for Fuchs corneal endothelial dystrophy: A proteomic study

Abstract

AbstractPurpose: Fuchs Endothelial Corneal Dystrophy (FECD) is characterized by the progressive slow accumulation of extra cellular matrix (ECM) forming Descemetic excrescents named guttae and by an increase in the thickness of the Descemet membrane (DM). Nevertheless, FECD pathophysiology remains only partially understood.Aim: To present the expression of newly identified proteins, using proteomics methods.Methods: DM were obtained from FECD patients undergoing DMEK and from donor corneas (controls) (University Hospital St‐Etienne). Some samples were analysed using MALDI imaging and shotgun proteomics (Kyoto, Doshisha University) to identified proteins selectively under or over expressed in FECD vs controls. Other samples were used for immunostaining (IS) of the top over‐expressed proteins. We used IS on flat mounts of DM in order to study the differences between the center and the periphery and cross sections to study the DM layer affected. Cross sections were performed using a cryostat on DM embedded in a mixture of gelatin, optimal cutting temperature compound and sucrose. Expression of each protein was observed using a fluorescence microscope. At least 3 different samples were used for each protein.Results: MALDI imaging and shotgun analysis identified 11 potential targets overexpressed in FECD, belonging to different families: mainly collagen, proteogylcans, and TGF beta signalling. Using IS, none of the 11 proteins was expressed in healthy samples, except for fibronectin. In FECD samples we identified proteins selectively expressed in different structures of the diseased DM: embryonic layers, Guttae, posterior fibrous layers. Notable differences were also observed between the periphery and the center.Conclusions: These new potential FECD markers located in different ECM abnormal structures suggest a dynamics phenomenon where different proteins are successively expressed and accumulated with time.