title: Influence of aromatase absence on the gene expression and histology of the mouse meibomian gland.
abstract: OBJECTIVE
  We hypothesize that aromatase, an enzyme that controls estrogen biosynthesis, plays a major role in the sex-related differences of the meibomian gland. To begin to test this hypothesis, we examined the influence of aromatase absence, which completely eliminates estrogen production, on glandular gene expression and histology in male and female mice.
  
  
  METHODS
  Meibomian glands were obtained from adult, age-matched wild-type (WT) and aromatase knockout (ArKO) mice. Tissues were processed for histology or the isolation of total RNA, which was analyzed for differentially expressed mRNAs by using microarrays.
  
  
  RESULTS
  Our results show that aromatase significantly influences the expression of more than a thousand genes in the meibomian gland. The nature of this effect is primarily sex-dependent. In addition, the influence of aromatase on sex-related differences in gene expression is predominantly genotype-specific. However, many of the sex-related variations in biological process, molecular function, and cellular component ontologies, as well as in KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, are remarkably similar between WT and ArKO mice. The loss of aromatase activity has no obvious effect on the histology of meibomian glands in male or female mice.
  
  
  CONCLUSIONS
  Our findings demonstrate that aromatase has a significant impact on gene expression in the meibomian gland. The nature of this influence is sex-dependent and genotype-specific; however, many of the sex-related variations in gene ontologies and KEGG pathways are similar between WT and ArKO mice. Consequently, it appears that aromatase, and by extension estrogen, do not play a major role in the sex-related differences of the mouse meibomian gland.
authors.affiliation: Schepens Eye Research Institute, Department of Ophthalmology, Boston, Massachusetts 02114, USA.
authors.forename: Raheleh Rahimi
authors.initials: RR
authors.lastname: Darabad
authors.forename: Tomo
authors.initials: T
authors.lastname: Suzuki
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Richards
authors.forename: Roderick V
authors.initials: RV
authors.lastname: Jensen
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Jakobiec
authors.forename: Fouad R
authors.initials: FR
authors.lastname: Zakka
authors.forename: Shaohui
authors.initials: S
authors.lastname: Liu
authors.forename: David A
authors.initials: DA
authors.lastname: Sullivan
mesh_terms: D000818:Animals; D001141:Aromatase / Q000172:deficiency*; D004967:Estrogens / Q000096:biosynthesis / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005838:Genotype; D008297:Male; D008537:Meibomian Glands / Q000201:enzymology*; D051379:Mice; D008807:Mice, Inbred BALB C; D046228:Microarray Analysis; D012333:RNA, Messenger / Q000235:genetics*
chemical_list: D004967:Estrogens; D012333:RNA, Messenger; D001141:Aromatase