The Dry Eye Zone

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Abstract: More technical stuff (yawn)

Sorry I'm so ho-hum on this. Some days I really dig these types of studies and other days... I don't. I love mucins and if anything could wake me up that should but somehow just not the right chemistry for me today. However, knowing I'll want to see it again (even if no one else does) I couldn't possibly omit these sorts of things from the blog.

Effect of pro-inflammatory mediators on membrane-associated mucins expressed by human ocular surface epithelial cells.
Exp Eye Res. 2009 Dec 28. [Epub ahead of print]
Albertsmeyer AC, Kakkassery V, Spurr-Michaud S, Beeks O, Gipson IK.
Schepens Eye Research Institute, Harvard Medical School, 20 Staniford Street Boston, MA 02114, USA.

Membrane-associated mucins are altered on the ocular surface in non-Sjögren's dry eye. This study sought to determine if inflammatory mediators, present in tears of dry eye patients, regulate membrane-associated mucins MUC1 and -16 at the level of gene expression, protein biosynthesis and/or ectodomain release. A human corneal limbal epithelial cell line (HCLE), which produces membrane-associated mucins, was used. Cells were treated with interleukin (IL)-6, -8, or -17, tumor necrosis factor-alpha (TNF-alpha), and Interferon-gamma (IFN-gamma), or a combination of TNF-alpha and IFN-gamma, or IFN-gamma and IL-17, for 1, 6, 24, or 48 h. Presence of receptors for these mediators was verified by RT-PCR. Effects of the cytokines on expression levels of MUC1 and -16 were determined by real-time PCR, and on mucin protein biosynthesis and ectodomain release in cell lysates and culture media, respectively, by immunoblot analysis. TNF-alpha and IFN-gamma each significantly induced MUC1 expression, cellular protein content and ectodomain release over time. Combined treatment with the two cytokines was not additive. By comparison, one of the inflammatory mediators, IFN-gamma, affected all three parameters-gene expression, cellular protein, and ectodomain release-for MUC16. Combined treatment with TNF-alpha and IFN-gamma showed effects similar to IFN-gamma alone, except that ectodomain release followed that of TNF-alpha, which induced MUC16 ectodomain release. In conclusion, inflammatory mediators present in tears of dry eye patients can affect MUC1 and -16 on corneal epithelial cells and may be responsible for alterations of surface mucins in dry eye. Copyright © 2009. Published by Elsevier Ltd.
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