Extracellular matrix changes and underlying genetic causes in a degenerative corneal disease called keratoconus

KeratoconusKeratoconus (1 in 2000), is a degenerative thinning of the cornea that affects people in the teenage years and progresses over 4-5 decades. It leads to the loss of vision and is the second most common reason for cornea transplants worldwide. While the etiology of keratoconus is not fully understood, interactions of genetic factors with environmental stressors are suspected to cause keratoconus. We hypothesize that the degenerative changes in the corneal ECM in keratoconus are due to pathogenic changes in the epithelium and keratocytes, and the altered ECMs they produce which in turn affect cellular functions. We further propose that these pathogenic changes are due to the accumulation of multiple individual deleterious genetic variants. Using a collaborative and interdisciplinary approach we are using whole exome sequencing (WES) to identify genetic variants in keratoconus families and isolated cases that increase disease susceptibility. Our WES studies of familial keratoconus have identified 8 genes with potentially damaging changes that we are exploring.keratoconus
Additionally, we are studying the transcriptomic and proteomic changes in the cornea of keratoconus subjects using discarded surgical tissues to help identify cell signal and ECM dysregulations that contribute to keratoconus. These studies identified increased stress response genes, decreased expression of ECM genes, NRF2-regulated antioxidant and tissue-injury response related genes in keratoconus {Shinde, 2020 #13160}. We are using the transcriptomic and proteomic profiles to select biologically significant genetic variants from our WES data. We intend to use CRISPR-Cas9 gene editing approaches in cell and cornea organoid cultures to determine functional consequences of the variants we have identified. These studies will identify major genes, biomarkers and pathway that contribute to keratoconus that may be used to improve diagnoses and treatments for keratoconus.