Abstract
Purpose: :
Sex–associated differences have been identified in the anatomy, physiology and pathophysiology of the human cornea. We hypothesize that many of these differences are due to fundamental variations in gene expression. Our objective in this study was to determine whether such differences do exist in human corneal epithelial cells both in vivo and in vitro.
Methods: :
Human corneal epithelial cells were isolated from the corneoscleral rims of male and female donors. Cells were processed either directly for RNA extraction, or first cultured in phenol red–free keratinocyte serum free media. The RNA samples were examined for differentially expressed mRNAs by using 20K CodeLink Bioarrays. Data were analyzed with GeneSifter.Net software.
Results: :
Our results demonstrate that sex significantly influences the expression of over 600 genes in human corneal epithelial cells (n = 3 uncultured cell samples/sex). Analyses showed a significant upregulation of 229 genes (e.g. vasoactive intestinal peptide receptor 1) in men, and 409 genes (e.g. secretory leukocyte protease inhibitor) in women. Some of the most significant sex effects were directed toward stimulation of genes associated with mitosis (male > female) and signaling pathways (female > male). However, with few exceptions (e.g. X– and Y–linked genes), these sex–related differences in gene expression in vivo were typically not maintained following cell culture in vitro (n = 4 total cell preparations/sex).
Conclusions: :
Our findings support our hypothesis that sex–related differences exist in the gene expression of human corneal epithelial cells.
Keywords: cornea: epithelium • gene/expression • gene microarray