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Exposure of a corneal epithelial cell line (hTCEpi) to Demodex-associated Bacillus proteins results in an inflammatory response.

Invest Ophthalmol Vis Sci. 2014 Oct 2;

Authors: McMahon F, Gallagher C, O'Reilly N, Clynes M, O'Sullivan F, Kavanagh K

Abstract
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 hTCEpi cells 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 corneal epithelial cells (hTCEpi) to 2 or 6 µg/mL Bacillus protein resulted in a dose dependent reduction in cell proliferation. Exposure of cells to 6 µg/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-1β (4.0-fold), IL-8 (11.1-fold) and TNF-α (4.1-fold). Increased expression of genes coding for the defensins, CCL20 (4.5-fold) and S100A7 (6.8-fold) was also observed. Elevated production of IL-6 and IL-8 was evident from cells exposed to 2 and 6 μg/mL Bacillus protein. hTCEpi cells demonstrated increased MMP-9 expression (3.2-fold, p = 0.003) and activity (2.2-fold, p = 0.0186) after 48 hours exposure to 6 µg/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.

PMID: 25277231 [PubMed - as supplied by publisher]

http://www.ncbi.nlm.nih.gov/pubmed/25277231?dopt=Abstract = URL to article