Expression, Regulation, and Effects of Interleukin-17f in the Human Ocular Surface

To evaluate the basal and possibly stimulated expression of interleukin (IL)-17 in the context of the ocular surface and potential downstream effects.

Western blot and immunofluorescent staining were used to evaluate IL-17F expression in human cornea/conjunctival tissues and cornea epithelial cell line. Cytokines and matrix metalloproteinase (MMP) transcripts were quantified by qPCR. IL-17F effects on NF-κB were investigated by the secretary alkaline phosphatase assay.

IL-17F was expressed in the cytoplasm of human corneal and conjunctival epithelial tissues. In the corneal cell line, exogenous IL-17F did not increase the NF-κB activity, but Pam3CSK4 increased IL-17F transcripts. IL-17F stimulated MMP-9 activity, promoted IL-6, IL-8, tumor necrosis factor-α transcripts levels, and depressed monocyte chemoattractant protein-1 expression, but did not affect transforming growth factor beta-1 transcript levels.

Normal corneal/conjunctival epithelial cells express IL-17F. Microbial agents may stimulate IL-17F via the NF-κB pathway. Matrix dissolution stimulated by IL-17F may have a role in the melting and necrosis of cornea in severe inflammation.