EMILIN-1 (Elastin Microfibril Interface Located Protein) is Present in Lens Capsule-Associated Pseudoexfoliation Material

Abstract

Purpose: : EMILIN-1 is an extracellular matrix protein that is known to interact with elastin, a known component of pseudoexfoliation material (PXFM). We demonstrate the presence of EMILIN-1 in lens capsule-bound pseudoexfoliation material (PXFM).

Methods: : Lens Capsules (LC) and aqueous humor (AH) were obtained from normal and pseudoexfoliation (PXF) patient eyes during cataract extraction surgery through avascular cornea and without contamination by hemorrhage. Proteomic analysis of aqueous humor and lens capsule was performed using electrospray tandem mass spectrometry. Immunofluorescence (IF) was conducted on lens capsules taken from normal and PXF patients. Western blotting for EMILIN-1 was performed on pooled solubilized LC (minimum 7 specimens/sample) and AH (minimum 2 specimens/sample) from normal and PXF eyes. GeneGo protein interaction software was used to map out interactions with EMILIN-1 with other proteins that we have idnetified as being associated with PXF material.

Results: : Proteomic analysis of LC and AH differentially identified the presence of EMILIN-1 in the AH of PXF eyes. Immunofluorescence localized EMILIN-1 to PXF material bound to lens capsule epithelium. Western blot analysis demonstrated a ~70 kDa EMILIN-1 protein band in both normal and PXF AH of comparable size. In silico, EMILIN-1 is closely associated with LOXL1, TGF-beta1, Elastin and other known PXF material components.

Conclusions: : EMILIN-1 was identified in PXFM found on lens capsule epithelium and in AH. This finding contributes to the growing body of knowledge of PXFM constituents. EMILIN-1 is an extracellular matrix protein that interacts with Elastin. We believe EMILIN-1 from the AH precipitates in association with elastin form PXF material. Further study is warranted to map the entire list of PXFM component proteins.

Keywords: anterior chamber • proteomics • microscopy: light/fluorescence/immunohistochemistry