Distribution of syndecans 1-4 within the anterior segment of the human eye: expression of a variant syndecan-3 and matrix-associated syndecan-2.
Control of the actomyosin network plays a role in regulating the movement of aqueous humor through the anterior segment of the eye. Receptors that could control its activity are unknown. In this study, we show that all four members of the syndecan family, which can regulate the actomyosin network, are present within the anterior segment. In both sections of human anterior segments and cultures of human trabecular meshwork (HTM), Schlemm's canal (HSC) and the ciliary muscle (HCM) cells from the anterior segment, syndecans-3 and -4 were the predominant family members. They were widely distributed throughout the anterior segment. Syndecan-3 within the anterior segment was a novel, recently described variant 55 kDa form. Low levels of syndecans-1 and -2 were also observed in situ and in all three cultures. Their expression was weaker and more localized than that observed for syndecans-3 and -4. Staining for syndecan-1 in HCM cultures was variable. In HTM and HSC cultures, syndecan-2 also co-distributed with fibronectin, laminin and type IV collagen suggesting that it was shed and associated with the extracellular matrix. Western blots supported this idea and showed syndecan-2 ectodomains in lysates from anterior segments.
Filla
Mark S
MS
Department of Ophthalmology & Visual Sciences, University of Wisconsin, Madison, USA.
David
Guido
G
Weinreb
Robert N
RN
Kaufman
Paul L
PL
Peters
Donna M
DM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000869:Anterior Eye Segment / Q000737:chemistry*; D015153:Blotting, Western / Q000379:methods; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000737:chemistry; D006801:Humans; D008562:Membrane Glycoproteins / Q000032:analysis; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D011509:Proteoglycans / Q000032:analysis*; D053668:Syndecan-1; D053669:Syndecan-2; D053670:Syndecan-3; D053671:Syndecan-4; D053667:Syndecans
D008562:Membrane Glycoproteins; D011509:Proteoglycans; C508241:SDC1 protein, human; C508245:SDC2 protein, human; C508301:SDC3 protein, human; C508304:SDC4 protein, human; D053668:Syndecan-1; D053670:Syndecan-3; D053671:Syndecan-4; D053667:Syndecans; D053669:Syndecan-2