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    Exposure of a Corneal Epithelial Cell Line (hTCEpi) to Demodex-Associated Bacillus Proteins Results in an Inflammatory Response

    McMahon, Frederick W. and Gallagher, Clair and O'Reilly, Niamh and Clynes, Martin and O'Sullivan, Finbarr and Kavanagh, Kevin (2014) Exposure of a Corneal Epithelial Cell Line (hTCEpi) to Demodex-Associated Bacillus Proteins Results in an Inflammatory Response. Investigative Ophthalmology & Visual Science, 55 (10). pp. 7019-7028. ISSN 0146-0404

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    PURPOSE. A role for a bacterium, Bacillus oleronius, originally isolated from a Demodex mite, in the induction of ocular rosacea has been proposed. The aim of this work was to characterize the response of a corneal epithelial cell line to Bacillus proteins, as this might give an insight into how such proteins contribute to the symptoms of ocular rosacea in vivo. METHODS. The effect of exposing Bacillus protein preparation on human telomeraseimmortalized corneal epithelial cells (hTCEpi) was measured by monitoring changes in cell proliferation and the expression of a number of genes associated with inflammation. The production of inflammatory cytokines was measured and the expression and activity of MMP- 9 was quantified. RESULTS. Exposure of hTCEpi cells to 2 or 6 lg/mL Bacillus protein resulted in a dosedependent reduction in cell proliferation. Exposure of cells to 6 lg/mL Bacillus protein did not induce apoptosis, but there was an increase in the expression of genes coding for IL-6 (13.8-fold), IL-1b (4.0-fold), IL-8 (11.1-fold), and TNF-a (4.1-fold). Increased expression of genes coding for the defensins, CCL20 (4.5-fold) and S100A7 (6.8-fold) also was observed. Elevated production of IL-6 and IL-8 was evident from cells exposed to 2 and 6 lg/mL Bacillus protein. The hTCEpi cells demonstrated increased MMP-9 expression (3.2-fold, P ¼ 0.003) and activity (2.2-fold, P ¼ 0.0186) after 48 hours of exposure to 6 lg/mL Bacillus protein preparation. CONCLUSIONS. The results suggest that interaction of Demodex-associated Bacillus proteins with the corneal surface could lead to tissue degradation and inflammation, possibly leading to corneal scarring.

    Item Type: Article
    Additional Information: The definitive published version of this article is available at DOI: 10.1167/iovs.14-15018
    Keywords: Bacillus; corneal surface; corneal scarring; Demodex; ocular rosacea; sterile ulcers;
    Academic Unit: Faculty of Science and Engineering > Biology
    Item ID: 6895
    Identification Number:
    Depositing User: Dr. Kevin Kavanagh
    Date Deposited: 20 Jan 2016 13:20
    Journal or Publication Title: Investigative Ophthalmology & Visual Science
    Publisher: Association for Research in Vision and Ophthalmology
    Refereed: Yes
      Use Licence: This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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