Abstract
Purpose: :
The vitreous body (VB) and the inner limiting membrane (ILM) are dominant extracellular matrix compartments of the posterior eye chamber. Goal of the project was to establish a comprehensive map of all extracellular matrix proteins in VB and ILM.
Methods: :
By using SDS PAGE, heparin affinity chromatography and mass spectrometry, the proteomes of the vitreous and the ILM of the chick embryo were analyzed.
Results: :
Forty ECM proteins were detected in the vitreous. Eleven proteins were members of the collagen family and 8 were proteins that are typically found in BMs. The most abundant ECM proteins in VB were collagen II, tenascin, collagen IX, and fibrillin. The analysis of the ILM revealed 24 ECM proteins. The most abundant proteins were nidogen 1, 2, followed by laminin 121 and 521. Three heparan sulfate proteoglycans were detected, agrin, perlecan and collagen XVIII. New proteins were FREM2 and FRAS1. Both proteins were identified from mouse and human mutations with severe eye abnormalities. Many of our mass spec IDs were confirmed by western blotting and immunocytochemistry.
Conclusions: :
The unbiased proteomics approach not only provided a comprehensive list of all ECM proteins in the VB and the ILM, it also presented semi-quantitative measures of the abundance of proteins in both ECM compartments.
Keywords: extracellular matrix • vitreous • proteomics