Inducible Inhibition of Cripto Specifically in Trophoblast Cells at Days Post Implantation Leads to Reduce Blood Supply to The Embryo
AWARD NOMINEE

Introduction

During embryo implantation, adhesion is immediately followed by the uterine angiogenesis. Cripto is a multifunctional signaling factor that stimulates cellular effects including angiogenesis. Previously, we have demonstrated that Cripto is essential for embryo implantation.

Aim

To explore the role of Cripto in placenta formation at early days of pregnancy.

Materials and Method

Embryos were infected with lentiviruses harboring a doxycycline (DOX)-inducible Cripto antagonist, ALK4-Fc, with Neptune protein as a marker for inducible expression. Those embryos were return to psudopregnant females that were given DOX in their drinking water or not on day E6.5, two days after implantation. The Females were sacrificed at day E9.5 and implantation sites were counted and taken for histological examination of placenta angiogenesis.

Results

Only embryos exposed to DOX expressed Neptune, indicating inducible expression of Neptune and thus ALK4-Fc. Examination of implantation site immediately upon their removal from the uteri revealed normal phenotype in 90% of implantation sites isolated from the non-treated females, as compared to 53% of pre-absorbed or absorbed implantation sites in uteri isolated from DOX-treated females. Histological examination of those implantation sites revealed reduced blood supply to the embryos in those implantation sites. This was confirmed by injection of dextran-Texas red i.v. into to the tail vain. We further found reduction in blood accumulation in implantation sites with inhibited Cripto as well as reduced and shallow embryo invasion to the mother uterus.

Conclusion

Cripto inhibition at days E6.5-E9.5 of pregnancy results in shallow invasion of the embryo to the mother uterus and reduced blood supply to the embryo.