İnvestigation of hippo signaling pathway in peri-i̇mplantation period mouse uteri and i̇mplantation sites

Objective: The events in uterus during peri-implantation period are critical for healthy progression and termination of pregnancy. These include development of embryo, acquisition of uterine receptivity, implantation and decidualization. Hippo signaling pathway was first discovered in Drosophila melanogaster that regulates organ size and then was demonstrated in mammals too. Hippo signaling pathway regulates cell number by regulating cell proliferation, apoptosis and differentiation. In this study, we aimed to determine localization and expressions of YAP, pYAP, TEAD1 and CTGF which are members of Hippo signaling pathway in peri-implantation mouse uteri and implantation sites. Method: One male and two female Balb/C mice were kept in same cage overnight, following day female with vaginal plaque were accepted on first day of pregnancy. Uteri and implantation sites of mice on days 1, 4, 5, 6 and 8 of pregnancy and uteri of female mice in estrous phase were obtained. Expressions of YAP, pYAP, TEAD1 and CTGF in these tissues were quantitatively determined by Western blot, localizations were determined by immunohistochemistry and were evaluated semi-quantitatively. Results: YAP, pYAP, TEAD1 and CTGF were expressed at different concentrations in uteri and implantation sites of different pregnancy days. In regions where proliferation takes place, YAP-TEAD1 and thus CTGF expressions increased; pYAP expression was increased in regions where differentiation occur. It was observed that pYAP expression was high, YAP and CTGF expressions were low in lumen epithelium of implantation sites on 5th day of pregnancy when implantation takes place. It was observed that pYAP expression was low, YAP and CTGF expressions were high in implantation sites on 6th day of pregnancy when decidualization occurs. Conclusion: Our findings suggest that Hippo signaling pathway may have a role in implantation and decidualization in mice. Key words: implantation, YAP, pYAP, TEAD1, CTGF