Sex-related effect on gene expression in the mouse meibomian gland

Sex-related differences have been identified in the anatomy and physiology of the meibomian gland. We hypothesize that these differences are due, at least in part, to variations in gene expression. This study's objective was to determine whether sex-related differences do exist in meibomian gland gene expression. We also sought to elucidate whether such differences, if any, might be (a) analogous to those known to occur in the lacrimal gland and (b) due to the effect of sex steroids.

Meibomian glands were obtained from young adult male and female BALB/c mice (n=7 to 15 mice per sex per experiment), pooled according to sex and processed for the isolation of RNA. Samples were evaluated for differentially expressed mRNAs by using CodeLink Bioarrays and GEM 1 and 2 gene chips. Bioarray data were analyzed with GeneSifter. Net software and also compared with microarray data in GEO and GeneSifter databases.

Our results demonstrate that sex has a significant influence on the expression of 164 genes in the mouse meibomian gland. These genes are involved in a broad spectrum of biological processes, molecular functions, and cellular components, including such activities as metabolism, catalysis, cell growth and maintenance, membrane architecture, nucleic acid binding, transcription, and signal transduction. In addition, the nature of the sex-related variations in meibomian gland gene expression is quite different from those in the lacrimal gland and appear to be mediated in part by the action of androgens, but not estrogens or progestins.

These findings support our hypothesis that sex-related differences exist in gene expression of the meibomian gland.