Abstract
Purpose: :
To determine whether glaucomatous trabecular meshwork (TM) has a different glycoprotein profile than normal controls. To determine whether differences in glycoprotein profile is likely due to changes in protein expression (glycoproteins and glycosyltransferases) and due to differences in sugar biosynthesis.
Methods: :
Human cadaver eyes (n=15 glaucoma and controls each) were used for these studies. Differential quantitative mass spectrometry of lectin precipitated TM proteins, analysis of TM microarray data, biotinylated lectin mediated TM histochemistry, Fluorophore assisted carbohydrate analysis (FACE) and bound-protein analysis.
Results: :
Biotinylated lectin mediated histochemistry revealed elevated glycoproteins in the glaucomatous TM in contrast to controls. In contrast, the FACE analysis showed elevated as well as decreased levels of sugars suggesting hypo and hyper glycosylation of TM glycoproteins. Quantitative mass spectrometry analysis suggests increased expression for some glycoproteins while decreased expression for some others.
Conclusions: :
Quantitative proteomics of lectin precipitated proteins taken together with FACE analysis suggests altered expression of proteins as well as sugar biosynthesis in the glaucomatous TM.
Keywords: glycoconjugates/glycoproteins • trabecular meshwork • protein modifications-post translational