Global genomic analysis of endometrial genes critically involved in the invasive phase of murine implantation

FRANCHI, A; ESTEBAN, FJ; BOCA, S; SWANSON, RJ; OEHNINGER, S; HORCAJADAS, JA

Glasgow, Scotland

Congreso; Society for Gynecologic Investigation 2009 Annual Meeting; 2009

Society for Gynecologic Investigation

Background: Embryo implantation involves an adhesion step followed by a phase of invasion during which trophoblastic cells penetrate into the endometrial stroma. Since physiological studies of early pregnancy are not possible in humans, we used a murine model to study molecular events associated with the invasive phase of implantation. Objective: To compare the gene expression profile of the mouse implantation site (IS) vs. inter-implantation sites (neighboring deciduas, IIS) on days 5 and 8 of pregnancy using microarray (MA) technology. Materials and methods: In pregnant B6CBA F1/J mice IS and IIS were dissected and RNA was extracted with Trizol followed by Qiagen RNeasy column. Gene expression analysis was performed using a mouse MA containing more than 46,000 probes. The gene expression of the IS vs. IIS at two different time points was compared by applying a t-test between the two groups of MA. Results: We found 387 genes differentially expressed >3.0 times at the IS on day 5 (253 up- and 134 down) and 1,087 on day 8 (606 up and 481 down), while 176 genes were differently expressed in both comparisons. Quantitative PCR was used for validation. By gene ontology classification, significantly differentially expressed genes were grouped into different gene families. Most up-regulated genes had functions related to cell adhesion, proteolysis, angiogenesis, apoptosis, immunoresponse, inflammatory regulation, cell differentiation and blood vessels morphogenesis. Implantation sites showed a high number of over-represented biological terms, such as cancer, cellular development, cell death, cellular movement and cellular growth and proliferation. Cancer was one of the more significantly over-represented in both, days 5 and 8. Conclusions: These results showed that gene expression profiling of the mouse uterus is significantly different between the IS and neighboring IIS at days 5 and 8 of pregnancy. Identification of these differentially regulated genes constitutes a first global approach to understand the expression profiles during implantation and sets the stage for future investigations to elucidate the molecular mechanisms of the invasive phase of implantation.