Abstract
Abstract: :
Purpose: Membrane CD44 anchors cells to the extracellular matrix through multiple interactions, which, if disrupted, can result in apoptosis. The ectodomain of membrane CD44 is shed as soluble CD44 (sCD44). We have previously demonstrated that sCD44 is significantly increased in primary open-angle glaucoma (POAG). The purpose of this study was to determine if exogenous sCD44 affects trabecular meshwork (TM) cell survival. Methods: Bovine TM cells were grown in Dulbecco's Modified Eagle's Medium (DMEM) containing 10% fetal calf serum (FCS) until confluent. The cells were washed twice with PBS, and incubated in DMEM containing 0.1% FCS with 10, 20, or 40 ng/ml purified sCD44, 10 ng/ml heat-inactivated sCD44, or PBS for 12, 24, and 48 hours. TM cell viability was assessed by trypan blue staining and total cell number was determined by cell counting. Results: Bovine TM cells revealed morphological changes that included cell rounding, cell detachment, and cell aggregation within 24 hours of incubation with the sCD44. There was a time-dependent and dose-dependent decrease in cell number and cell viability in bovine TM cells exposed to the sCD44. Number and viability of cells treated with the heat-inactivated sCD44 preparation were not significantly different from the PBS-treated cells. Conclusion: The results indicate that exogenous sCD44 adversely affects bovine TM cells survival. Disruption of membrane CD44 activity by sCD44 may be responsible for the loss of TM cells that occurs in POAG.
Keywords: 323 apoptosis/cell death • 541 receptors: pharmacology/physiology • 601 trabecular meshwork