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Invest Ophthalmol Vis Sci. 2014 Oct 2;55(10):7019-28. doi: 10.1167/iovs.14-15018.

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

Author information

1
Department of Biology, National University of Ireland Maynooth, County Kildare, Ireland.
2
National Institute for Cellular Biotechnology, Dublin City University, Glasnevin, Dublin, Ireland.

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 human telomerase-immortalized 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 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) also was observed. Elevated production of IL-6 and IL-8 was evident from cells exposed to 2 and 6 μg/mL Bacillus protein. The hTCEpi cells demonstrated increased MMP-9 expression (3.2-fold, P = 0.003) and activity (2.2-fold, P = 0.0186) after 48 hours of 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.

KEYWORDS:

Bacillus; Demodex; corneal scarring; corneal surface; ocular rosacea; sterile ulcers

PMID:
25277231
DOI:
10.1167/iovs.14-15018
[Indexed for MEDLINE]

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