Abstract
Purpose:
This study sought to determine bacteri- and fungi-cidal activities of corneal epithelial secreted peptides, S100A8, S100A9, CXCL10, and Chi3L1 and their expression in response to microbial infection.
Methods:
Three ocular pathogens, Staphyloccocus aureus, Canidia albicans and Pseudomonas aeruginosa, were used to challenge B6 mouse cornea and the expression of antimicrobial peptides was determined by Real-time PCR in corneal epithelial cells. In vitro bacteri- and fungi-cidal activities were assessed using incubation of pathogens with peptides in PBS, followed by plate colony counting. In vivo role of S100A8 (100 ng in 5 μl PBS) and CXCL10 (500 ng in 5 μl PBS) were determine by subconjunctival injection of peptides prior to inoculation and topical application 4 h post infection.
Results:
The expressions of all 4 peptides, S100A8, S100A9, CXCL10 and Chi3L1, were highly inducible in corneal epithelial cells in response to microbial infection. In vitro, these peptides exhibited different bactericidal and/or fungicidal activity under physiological slat concentration. Subconjunctival injection S100A8 or CXCL10 prior to and 4h after ATCC or C. albicans inoculation significantly attenuated the development of microbial keratitis using pathogen burden as the readout of infection.
Conclusions:
Corneal epithelial cells express and secrete antimicrobial peptides in response to infection and synthetic AMPs, alone or in combination can be used to control ocular infection.
Keywords: 482 cornea: epithelium