Abstract
Purpose: :
Pseudoexfoliation (PXF) glaucoma is the most commonly identifiable form of secondary glaucoma and is associated with the presence of pseudoexfoliation material (PXFM) on the lens capsule. Using proteomic and molecular approaches, we identified proteins that are not present in the pseudoexfoliation material but which are differentially expressed in the lens capsule of pseudoexfoliation patients compared to lens capsules from normal patients without pseudoexfoliation. These proteins may serve as possible markers for systemic diseases associated with pseudoexfoliation.
Methods: :
This research was performed in adherence to the Declaration of Helsinki. Lens capsules were removed from patients undergoing routine cataract extraction surgery and who were not medicated with ocular glaucoma medications. Proteomic techniques utilizing two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) were used to identify and sequence by MALDI-TOF mass spectrometry PXF-specific lens capsule proteins. Fractionation on 1-D PAGE, in-gel trypsinization, and liquid chromatography tandem mass spectrometry (LC MS/MS) identified proteins expressed in PXF and control lens capsules. The differential expression of PXF lens capsule proteins was then verified by Western blotting and expression pattern localized using immunostaining.
Results: :
LC MS/MS identified a number of proteins that were differentially expressed in lens capsules from patients with PXF compared to normal controls. Some of these proteins were specifically localized to PXF material. Surprisingly, a number of proteins including crystallins, histones, keratins, and laminins were localized to the lens capsule epithelium and not within PXF material. The differential expression of these proteins identified using proteomic approaches was verified by Western blot analysis.
Conclusions: :
The presence of pseudoexfoliation material has definite association with a disease of the eye - glaucoma. However, PXFM has been observed throughout the body and conflicting reports suggest PXF may be associated with systemic diseases. Using differential proteomic and molecular approaches, we have identified proteins that are differentially expressed in the lens capsule, especially within the lens epithelium, but not in PXFM. These proteins, which are intrinsically and differentially expressed within the lens capsule, represent proteins that may serve as markers for systemic disease associated with the production of pseudoexfoliation material.
Keywords: proteomics • anterior segment • pathology: experimental