Project Summary/Abstract Fuchs Endothelial Corneal Dystrophy (FECD) is a major cause of vision loss and a leading indication for corneal transplantation. A healthy corneal endothelial cell layer pumps fluid out of the corneal stroma to maintain the optimal hydration state for corneal transparency. Late-onset FECD is caused by loss of endothelial function and is linked to dominant inheritance of mutations in several genes including SLC4A11. SLC4A11 encodes an endothelial H+ transporter. The development of non-invasive therapies for older individuals to prevent or delay FECD onset would obviate the need for transplants. However, therapeutic advances have been hindered by a lack of understanding of the molecular mechanisms that underlie onset of this complex disease and a lack of suitable and diverse animal models for developing and testing therapies. To address both issues, a transgenic mouse-line has been generated that carries the dominant human FECD mutant Trp240Ser (W240S) in its SLC4A11 gene. W240S heterozygous mice develop edema and signs of reduced antioxidant capacity, but not diagnostic guttae. The hypothesis of this study is that these mice are more susceptible to oxidative stress and will model FECD upon UVA-light exposure. There are two aims [1] Examine the molecular consequences of the W240S mutation on endothelial health. [2] Examine the link between SLC4A11 mutation and phenotype. The proposed research is both significant and innovative because it the first genetic mouse model that recreate signs of late-onset FECD and uses novel tools and a multidisciplinary approach that will inform the development of new early-diagnostic, risk-scoring, and therapeutic approaches for FECD.