Abstract
Purpose: :
To evaluate the involvement of tumor necrosis factor-alpha converting enzyme (TACE, ADAM17) in ectodomain shedding of TNF receptor in conjunctival epithelium.
Methods: :
The corneal alkali burn of BALB/c mice was made using a filter paper dipped in 1N NaOH solution. TNF receptor 1 (TNFR1) expression in conjunctiva was evaluated by immunohistochemistry with time course (3eyes each). In vitro experiments were performed using human conjunctival epithelial cell (HCjEC) line. Peptidoglycan (PGN, 100µg/mL, 24hours) alone or PGN and TACE inhibitor (TAPI-1, 250µg/mL, 4hours) were added to HCjEC medium. s (soluble) TNFR1 concentration in supernatant of the culture medium was analyzed by ELISA.
Results: :
In corneal alkali burn model, TNFR1 was expressed in conjunctival epithelium 14 days after the alkali burn. In HCjEC cultured medium, sTNFR1 release was significantly increased by adding of PGN (t-test, p<0.05). This increased release of sTNFR1 was significantly inhibited by TAPI-1 (t-test, p<0.05), indicating the participation of TACE in this sTNFR1 releasing process.
Conclusions: :
In conjunctiva, TNFR1 was expressed in the epithelium after the corneal alkali burn and TACE dependent shedding of sTNFR1 was recognized in conjunctival epithelium. sTNFR1, released from ocular surface, might play anti-inflammatory role in inflammatory condition by neutralizing TNF-α.
Keywords: inflammation • conjunctiva • cytokines/chemokines