P-343 The role of Yes-Associated protein (YAP) activity in uterus adenogenesis process
Authors: İnanç İ , Bender O , Atalay A , Köse S K , Erdemli E 
Published: June 2023

Abstract

Study question
Could Yes-Associated protein(YAP) be effective in the adenogenesis process that occurs in the mouse uterus in the postnatal period?

Summary answer
It was observed that the YAP and phospho-YAP levels decreased in mice with inhibited gland development during adenogenesis process when compared to the control groups.

What is known already
The mouse uterus is composed of undifferentiated mesenchyme surrounded by a single layer of epithelium at birth. On the 5th Postnatal Day (PD), the luminal epithelium begins to bud, and the process called adenogenesis, which is termed as gland development in the uterus, begins. The gland development is evident on the PD 10th day. The uterus shows adult tissue characteristics by PD 15th-20th days. Although it has been stated that various signaling pathways are active in this process, Hippo signaling pathway role in the adenogenesis process have not been clarified yet.

Study design, size, duration
The uterus with normal gland development and gland development inhibited by Progesterone were evaluated for YAP and phospho-YAP, which is one of the main components of Hippo signaling pathway, by immunohistochemistry, western blotting, and q-RT-PCR methods. For experimental groups, 50 µg/g Progesterone was dissolved in 0.1 mL Sesame oil and for control groups, only 0.1 mL of Sesame oil given subcutaneously on PN 2nd-10th days. Animals were sacrificed on the PN 5th-10th and 15th days.

Participants/materials, setting, methods
In total of 30 newborn Balb/c female mice were used. They were divided as control (n = 15) and experimental(n = 15) groups. After the injections were finished, mice from both groups at PN5th(n = 5), PN10th(n = 5), and PN15th(n = 5) days were cervical dissociated, and uteri were collected. For immunohistochemical analyses, tissues were taken into buffered formalin, paraffin blocks were made, and the sections were taken. Protein and RNA isolations were performed from uteri for western blotting and q-RT-PCR analyses, respectively.

Main results and the role of chance
When YAP expression was evaluated by immunohistochemistry, western blotting and q-RT-PCR methods, there was no difference between the groups on the PN 5th day. But there was an active signaling was observed in the control groups on the PN10th day, which is very important for gland formation, and on the PN 15th day, that is effective in the maturation process. On the PN10th and 15th days, it was determined that YAP and phospho-YAP signal expression were decreased significantly in the experimental groups when compared with the control groups in immunohistochemically and protein levels. In addition, these findings were supported by mRNA analysis with YAP.

Limitations, reasons for caution
The study was performed in vivo mouse model. Further studies can be done with a transgenic animal model.

Wider implications of the findings
Considering the contribution of uterine gland development to the implantation process, errors in the development of these glands may cause infertility. This study can bring a new perspective to researching the uterus adenogenesis period and causes of infertility and treatment approaches.

Trial registration number
not applicable