Abstract
Abstract: :
Purpose: Our previous research has indicated that sex-related differences may exist in gene expression in the mouse meibomian gland. These differences were identified by the use of Clontech’s Atlas Mouse cDNA Expression Arrays (588 genes/array), as well as cDNA amplification techniques. The purpose of the present study was to confirm and extend these preliminary findings by utilizing additional molecular procedures. Methods: Meibomian glands were obtained from adult BALB/c mice (n = 10/sex/experiment), pooled according to sex, processed for the isolation of RNA and analyzed for differentially expressed mRNAs by using GEM 2 (> 9,500 genes) gene chip and/or real-time PCR procedures. Chip data were evaluated with Rosetta Resolver software. Results: Our results show that apparent sex-associated differences in the mRNA levels of proliferating cell nuclear antigen, cathepsin D, nucleobindin and fibroblast growth factor 7, that had been identified with repeated Clontech arrays, could not be confirmed by real-time PCR. In contrast, this latter method did confirm the up-regulation of stearoyl-CoA desaturase mRNA in meibomian glands of male (M), as compared to female (F), mice. The differential expression of this mRNA, which encodes a key enzyme in fatty acid biosynthesis and is regulated by androgens, had previously been identified with cDNA amplification and sequencing techniques. Gene chip methodology indicates that sex-related differences (> 1.7 fold) occur in the expression of over 25 meibomian gland genes. At present, assessment of two of these genes by real-time PCR has confirmed the differential expression of inactive X specific transcripts (F>M, 26-fold) and odorant-binding protein (M>F, 20-fold).Conclusions: Our findings confirm that sex-associated differences exist in gene expression in the mouse meibomian gland. Our results also underscore the importance of identifying such differences by using at least two separate methods. (Supported by research grants from NIH [EY05612], Allergan, the German Research Society DFG and the Sjogren’s Syndrome Foundation)
Keywords: cornea: tears/tear film/dry eye • lipids