Abstract
Abstract: :
Purpose: CAP37 is a multifunctional inflammatory mediator demonstrated to be a critical player in the innate defenses of the host. It is a natural antibiotic with strong immunomodulatory effects on monocytes and endothelial cells and is constitutively expressed in the granules of human neutrophils (PMN). Recently, CAP37 expression was observed in corneal epithelial cells in an in vivo rabbit model of Staphylococcus aureus keratitis. The hypothesis proposed is that CAP37, either released by PMN or induced in corneal epithelial cells at the site of infection plays a pivotal role in the regulation of corneal inflammation and healing by modulating leukocyte and corneal epithelial cell functions. To expand our knowledge on the molecular mechanisms involved in the CAP37-mediated effects on HCEC, we used gene expression array technology to determine the differential gene expression in CAP37-treated HCEC compared with untreated HCEC. Methods: Immortalized HCEC were treated with CAP37 for 4 and 24 hr. Total RNA from untreated and CAP37-treated HCEC at both time points were isolated and labeled using the Atlas Pure Total RNA labeling system. The probes were hybridized to plastic arrays from the Atlas Plastic Human 8K microarray (Clontech), which contain more than 8,300 named human genes, housekeeping genes, and negative controls. Results: Of the >8300 genes, CAP37 upregulated 475 genes at 4 hr post treatment and 177 genes at 24 hr post treatment when compared to untreated HCEC. Of the genes upregulated at the 100-fold level 14 were in common at both time points. The CAP37-responsive genes fell into several broad groups including, cell surface antigens, growth factor and chemokine receptors, death domain receptors, cell adhesion proteins, intracellular kinase network members, interleukins and interferons and their receptors. RT-PCR, Western blot and ELISA confirmed these findings. Conclusions: Our observations suggest that CAP37 regulates a number of genes with immunomodulatory, proliferative, signaling, and cell cycle activity, and give strong credence to our original hypothesis that CAP37 is involved in inflammation and wound healing in the corneal epithelium
Keywords: cornea: epithelium • inflammation • gene microarray