earticle

영어

The Hippo signaling pathway is essential for regulating proliferation, differentiation, and apoptosis in mammalian cells. It has been reported that the members of Hippo signaling pathway are highly expressed in mammalian ovaries and uteri. However, the regulatory mechanism of this pathway in the uterus during estrous cycle regulation remains unclear. Serine/Threonine Protein Kinase 4 (STK4) (known as MST1) is a major factor of Hippo signaling pathway. However STK4 in the mouse uterus has not yet been examined. The purpose of our study was to determine the expression of STK4 during the estrous cycle and regulation by estrogen in the mouse uterus. We found that Stk4 mRNA was dynamically expressed in uterine endometrium during the estrous cycle. The expression of Stk4 was significantly increased at the stage of estrus and diestrus among the estrus cycle, whereas its expression was decreased at proestrus and metestrus stages. The localization of Stk4 was highly detected in Luminal epithelial (LE) and Glandular epithelial (GE) in uterine endometrium. In addition, we demonstrated that Estrogen (E2) administration into ovariectomized mice increased the expression of Stk4 in the uterus. The expression of Stk4 by E2 was gradually increased depending on the time up to 6 hours after the treatment and then decreased. Moreover, the treatment the Estrogen receptor inhibitor, ICI 182, 780 (ICI), before E2 injection significantly reduced the alleviation of Stk4 expression by E2. Our results indicate that the Stk4 is expressed in Luminal epithelial (LE) and Glandular epithelial (GE) of the uterus and its expression in regulated by the ovarian hormone, Estrogen. These informations will give us on sights to understand uterine dynamics during the estrous cycle.