Identification of novel endometrial targets for contraception
using microarray technology
S Mirkin, S Oehninger
The Jones Institute for Reproductive Medicine, Norfolk, VA,
United States
Introduction A series of temporally and spatially
coordinated morphological and molecular changes are necessary for the
preparation of the receptive endometrium. We propose that altering events
associated with endometrial changes essential for implantation would provide an
opportunity for blocking implantation and hence could be used as a strategy for
developing contraception methods.
Objectives The objective of this study was to identify
candidate genes that could potentially be of high functional significance during
embryo implantation in the human endometrium and could be used as a
contraceptive targets.
Materials and methods We compare gene expression profiles
of the mid luteal phase (receptive endometrium) versus the early luteal phase (pre-receptive
endometrium) in healthy fertile volunteers. Endometrial biopsies were obtained
on day LH + 3 (day 16, early luteal phase) and on day LH+ 8 (day 21, receptive
endometrium). Total RNA was extracted for gene expression analysis using DNA
microarrays. cDNA synthesis and in vitro transcription were carried out to
create biotinylated cRNA’s using the Affymetrix GeneChip Fluidics Station 400,
and chemically fragmented cRNA samples were hibrydized on Affymetrix Hu 95A
microarray containing 12,000 full length previously characterized genes.
Following optical scanning data were analyzed using the GeneChip Analysis Suite.
Gene expression profiles were compared and concordant genes were analyzed using
SAM software.
Results With a false discovery rate of 0, the analysis
revealed that 107 genes were significantly and differently expressed (>
2-fold) between early luteal phase and the receptive endometrium (mid luteal
phase). Of these, 49 genes were up regulated whereas 58 were down regulated.
More than + 4 fold changes were demonstrated for 27 genes (msh homeo box
homolog 1 ¯7.45
fold; thymidylate synthetase ¯
5.90 fold; ZW10 interactor ¯
5.10 fold; KIAA0146
32.00 fold; interleukin 15
7.50 fold). Some of those genes were not previously reported as being involved
in the human embryo implantation. Random genes were selected and their
expression were validated using real time PCR.
Conclusions We have identified new candidate genes that
involved in the transition of early luteal phase to the endometrial receptivity
phase. We reported 107 genes that are potential candidates targets for
contraception. Ongoing functional studies will provide proof of the principle
that these genes are indeed contraceptive targets.