Abstract
Purpose :
Commensal bacteria on eyelids, such as Staphylococcus aureus and Cutibacterium acnes could produce sulfatase that catalyze the hydrolysis of sulfate esters. Sulfate proteoglycans such as heparan sulfate and keratan sulfate play critical roles in the homeostasis and barrier function of the corneal epithelium. However, little is known about the relationship between sulfatase and bacterial infection in corneal epithelium. This study was designed to investigate role of sulfatase in barrier function, bacterial adhesion, and internalization in corneal epithelial cells.
Methods :
Cultured Human Corneal Limbal Epithelium (HCLE) cells were incubated with 0.1% sulfatase originated from Helix pomatia. For determination of adhesion and internalization, Staphylococcus aureus (RN4220) (approximately 106 CFU in 1 ml of medium) were applied to HCLE cells stratified in 24-well flasks. Following incubation for 1 hour, epithelial cell cultures were washed, disaggregated, and adherent bacteria were counted by serial dilution. After killing residual extracellular bacteria using gentamicin, invaded bacteria were counted. The epithelial barrier function was evaluated by measuring transepithelial electrical resistance (TER) over time in 24-well trans-well culture medium containing 0.1% sulfatase.
Results :
Sulfatase treatment exhibited a significant reduction in bacterial adhesion and internalization in HCEC, compared to non-treatment. (Relative adhesion or internalization rate: Sulfatase vs no-treatment; adhesion: 0.33±0.11 % vs 0.49±0.10%, P<0.05; internalization: 0.20±0.09 % vs 0.46±0.18%, P<0.05). Sulfatase could reduce value of TER, over time, and a significant decrease in barrier function of more than 30% was observed from 2 hours to 6 hours (P<0.05).
Conclusions :
Sulfatase may inhibit bacterial adhesion and internalization into corneal epithelial cells. Meanwhile, sulfatase may reduce corneal barrier function. S. aureus on eyelids could damage corneal epithelium without infection to cells using sulfatase.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.