Abstract
Abstract: :
Purpose: Examine the distribution of the 4 members of the syndecan family of transmembrane heparan sulfate proteoglycans (HSPGs) within the trabecular meshwork/Schlemm's canal (TM/SC) system and the ciliary body of normal human eyes. Methods: Paraffin-embedded sections from eyes were labeled immunohistochemically with monoclonal antibodies against syndecans 1, 2, 3 or 4. Eyes were either placed into organ culture for 3-5 days prior to fixation and embedding or obtained directly from cadavers. Results: No syndecan-1 staining was observed within either the TM/SC system or ciliary body of all eyes examined. However, strong syndecan-1 staining was observed within the connective tissue stroma surrounding the outer wall of the SC. Weak syndecan-2 staining was variably observed within the TM/SC system; weak staining was also observed within the ciliary muscle (CM) of a majority of the eyes examined. Moderate syndecan-3 staining was observed within the TM/SC system although the staining was variable. In contrast, relatively strong syndecan-3 staining was observed within the CM of all eyes examined. Finally, strong cell-associated syndecan-4 staining was observed within the TM/SC system and throughout the ciliary body in all eyes examined. Conclusion: Syndecan family members are differentially localized within the TM/SC system and ciliary body of the eye with syndecans 3 and 4 being the most prominently localized. Reports have linked syndecans 3 and 4 to major signaling pathways in other cell types (src-mediated and integrin-mediated respectively), and both HSPGs can regulate the organization of the cytoskeleton. The identification of these syndecans within the TM/SC system and the ciliary muscle suggests they could participate in regulating aqueous outflow from the anterior chamber.
Keywords: 601 trabecular meshwork • 348 ciliary body • 529 proteoglycans/glycosaminoglycans