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S. Narayanan, A.M. McDermott; Proinflammatory Cytokines Upregulate Human ß-Defensin-2 Expression in Conjunctival Epithelial Cells: Relevance to Dry Eye Disease . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2490.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: We have previously shown (Narayanan S, ARVO Abstract #2624, 2001) that the antimicrobial peptide human ß-defensin (hBD)-2 is present in the conjunctival epithelium of moderately dry eye patients but not in normal control subjects, while hBD-1 and 3 are constitutively expressed. Recent evidence demonstrates increased proinflammatory cytokine activity in dry eye disease. Therefore, we investigated if proinflammatory cytokines can modulate the expression of hBD- 1, 2 and 3 by conjunctival epithelial cells in culture. Methods:Two conjunctival cell lines (Chang and NHC) and primary cultured conjunctival epithelial cells were treated with 10 ng/ml interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, IL-1ß+TNF-α or interferon (IFN)-γ (40 ng/ml) for 24 hours. RT-PCR was performed to detect mRNA for hBD-1, 2 and 3. hBD-1 and -2 protein secretion was detected by immunoblotting. The effect of treatment duration (2-24 hours) and concentration (0.1-100 ng/ml) of IL-1ß on hBD-2 expression was also studied. Results:RT-PCR demonstrated constitutive expression of hBD-1 and 3. hBD-2 mRNA was not expressed at baseline by the cell lines (n = 3) and was only weakly expressed by primary cultured cells (n = 2). Upregulation of hBD-2 mRNA was observed following IL-1ß, TNF-α, IL-1ß+TNF-α or IFN-γ treatment. There was no change in the expression of hBD-1 and 3 with cytokine treatment. Upregulation of hBD-2 mRNA was detected as early as 2 hours after treatment with 10 ng/ml IL-1ß and was maximal at 12 hours (n=2 cell lines; n=1 primary cells). 0.1 ng/ml of IL-1ß (for 24 hours) was sufficient to upregulate hBD-2 mRNA, with peak expression occurring with 10 ng/ml (n=2 cell lines; n=1 primary cells). hBD-1 protein was constitutively secreted, while hBD-2 secretion was upregulated in a pattern corresponding to the RT-PCR data. Conclusions:Proinflammatory cytokines induce the expression of hBD-2 by conjunctival epithelial cells. The upregulation of hBD-2 observed in moderately dry eye subjects in our previous study may be mediated by proinflammatory cytokines and would provide additional anti-microbial protection to the compromised ocular surface.
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