Abstract
Purpose: :
Recent studies have suggested that that iris thickness may be a risk factor in the development of chronic angle closure glaucoma. The molecular components of the iris tissue however have not been well characterized. These components likely influence iris biomechanics and may contribute to iris thickness. In this study, we performed a global proteomic analysis to identify the proteins expressed in the iris and to link these proteins to specific functions and roles.
Methods: :
Two fresh eye bank eyes, age 80 and 87 respectively, with no history of ocular diseases were obtained. Iris tissues were dissected and total protein was extracted. Tryptic digests of the complex mixtures of proteins were analyzed using Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS). Proteins were identified by searching the data against the human subset of the UniProt database and classified into functional categories using Scaffold 3 software.
Results: :
A total of 550 proteins were identified with Vimentin being the most dominant. 10% of the total proteins were extracellular matrix proteins (ECM); other proteins were involved in different functions such as: development (25%), adhesion (4%), antioxidant activity (2%) and other cellular processes such as cell killing and growth. Proteins previously implicated in glaucoma such as Prostaglandin D2 synthase, Opticin, Tranthyretin, and proteins from the SERPIN family were also detected.
Conclusions: :
Identification of the normal iris proteome forms the basis of further investigation of molecular components of iris tissue which may provide insights into the molecular mechanisms involved in chronic angle closure glaucoma.
Keywords: iris • proteomics • extracellular matrix