Abstract
Purpose :
Lipopolysaccharide (LPS), a bacterial toxin, is known to stimulate leuokotriene B4 (LTB4) secretion by human corneal, conjunctival and meibomian gland epithelial cells. We hypothesize that this LTB4 effect represents an overall induction of proinflammatory gene expression in these cells. Our objective was to test this hypothesis.
Methods :
We cultured immortalized human corneal (gift from Dr. James Jester, Irvine, CA), conjunctival (gift from Dr. Ilene Gipson, Boston, MA) and meibomian gland epithelial cells in the presence or absence of LPS (15 μg/ml) and ligand binding protein (150 ng/ml). Cells were then processed for the isolation of RNA and the evaluation of gene transcripts by utilizing Illumina BeadChips, background subtraction, cubic spline normalization and GeneSifter software.
Results :
Our findings show that LPS induces a striking increase in proinflammatory gene expression in human corneal and conjunctival epithelial cells. These cellular reactions are associated with a significant upregulation of genes associated with inflammatory and immune responses (e.g. IL-1 beta, IL-8, and tumor necrosis factor), including those related to cytokine-cytokine receptor interactions, chemokine and Toll-like receptor signaling pathways, and chemotaxis. In contrast, with the exception of Toll-like signaling pathways, almost no proinflammatory ontologies were upregulated by LPS in human meibomian gland epithelial cells.
Conclusions :
Our results support our hypothesis that LPS stimulates proinflammatory gene expression in human corneal and conjunctival epithelial cells. However, our findings also show that LPS does not elicit such proinflammatory responses in human meibomian gland epithelial cells.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.