Aberrant glycosylation in the human trabecular meshwork.
OBJECTIVE
To determine the difference in protein glycosylation and glycosylation enzyme levels between glaucomatous and control trabecular meshwork (TM).


METHODS
Glaucomatous and normal donor (n = 12 each) TM tissues, lectin fluorescence, fluorophore-assisted carbohydrate analyses, and quantitative MS were used to determine the glycosylation levels. Primary TM cells and glycosylation inhibitors were used to determine their effect on cell shape and motility.


RESULTS
In contrast to elevated levels of glycoproteins determined by lectin fluorescence, simultaneous hyper- and hypo-glycosylation in glaucomatous TM was revealed by fluorophore-assisted carbohydrate analyses. Analyses of enzymes showed elevation of beta-glycosidase 1 and decrease in galactosyltransferase family 6 domain containing protein 1 in the glaucomatous TM. Quantitative MS identified select protein level changes between glaucomatous and normal TM. Primary TM cells were treated with inhibitors to elicit hypo-glycosylation, which affected cell shape, motility, and fluorescent tracer transport across a layer of TM cells.


CONCLUSIONS
Global protein glycosylation is aberrant in glaucomatous TM compared to controls. The results presented here suggest that the alteration in global TM protein glycosylation encompassing cellular and extracellular matrix proteins contributes to glaucoma pathology likely mediated through changes in properties of TM cells.
Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA.
Adam E
AE
Sienkiewicz
Brandon N
BN
Rosenberg
Genea
G
Edwards
Teresia A
TA
Carreon
Sanjoy K
SK
Bhattacharya
D004798:Enzymes / Q000096:biosynthesis*; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D015971:Gene Expression Regulation, Enzymologic; D005901:Glaucoma / Q000235:genetics* / Q000473:pathology; D006031:Glycosylation; D006801:Humans; D014129:Trabecular Meshwork / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology
D004798:Enzymes; D016326:Extracellular Matrix Proteins
Carbohydrate electrophoresis; Glaucoma; Glycosylation; Trabecular meshwork