AUTHOR=Alauddin Md , Salker Madhuri S. , Umbach Anja T. , Rajaxavier Janet , Okumura Toshiyuki , Singh Yogesh , Wagner Anna , Brucker Sara Y. , Wallwiener Diethelm , Brosens Jan J. , Lang Florian 

TITLE=Annexin A7 Regulates Endometrial Receptivity

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2020.00770

DOI=10.3389/fcell.2020.00770

ISSN=2296-634X

ABSTRACT=<p>A limited window of receptivity is a prerequisite of reproductive success. Indispensable receptivity genes include cyclooxygenase 2 (COX2), an enzyme accomplishing formation of prostaglandin E<sub>2</sub> (PGE<sub>2</sub>). A powerful regulator of PGE<sub>2</sub> formation is Annexin A7 (<italic>ANXA7</italic>). The present study thus explored whether ANXA7 impacts on implantation and fertility. Here we show that <italic>ANXA7</italic> is expressed in endometrial tissue and increases upon decidual transformation of human endometrial stromal cells (HESCs) in a time-dependent manner. Silencing ANXA7 significantly decreased the expression of <italic>PRL</italic> and <italic>IGFBP1</italic>, canonical decidual marker genes, but enhances COX2 and PGE<sub>2</sub> levels. Genetic knockout of <italic>AnxA7</italic> in mice significantly increases the number of implantation sites and litter sizes. Further, analysis of human endometrial biopsies showed that <italic>ANXA7</italic> transcript and protein levels are decreased during the midluteal window of implantation in women suffering from recurrent pregnancy loss (RPL) when compared to subfertile patients. Taken together, the data indicate that ANXA7 has a conserved role in regulating endometrial receptivity and implantation.</p>