Proteomic analysis of aqueous humor proteins associated with cataract development.

BACKGROUND Cataract is one of the most common eye diseases that can further cause blindness. Discovering susceptibility factors contributing to cataract development is helpful in identifying predisposed patients and improving treatment efficacy. Although proteomics technology has been used in study of protein markers related to eye diseases, few were on studies of cataract development. METHODS To explore cataract-associated susceptibility factors in aqueous humor (AH), a quantitative proteomics study using the iTRAQ methodology was employed to compare AH protein profiles between high myopia patients & controls, glaucoma surgery patients & controls, and vitrectomy surgery patients & controls, respectively. RESULTS A total of 445 AH proteins were identified, and 210 proteins were differentially expressed between myopia patients and controls, 262 proteins were differentially expressed between glaucoma surgery patients and controls, and 161 proteins were differentially expressed between vitrectomy surgery patients and controls. Among the 445 identified proteins, 77 were considered to be cataract-associated, and 5 of the 77 proteins were randomly selected and confirmed by ELISA assay. Biological functions of these 77 proteins were annotated by GO/pathways analysis. Additionally, 17 proteins were found to be involved in protein-protein interaction networks, 5 of which were associated with nervous system disease and eye diseases including cataract. CONCLUSIONS The identified candidate protein biomarkers associated with cataract development may lead to more insights into the underlying mechanisms of cataract disease.