Analysis of uteroplacental-specific molecules and their functions during implantation and placentation in the bovine

Abstract

In cattle, the mechanisms underlying implantation and placental development are still unclear. Synepitheliochorial placentation in cattle is noninvasive, and thus generates limited interest in terms of degradation and remodeling of endometrial tissues. The overall purpose of this study was three-fold: (1) to examine the gene circuitry around the implantation window, (2) to understand development of the placenta during the peri-implantation period by using a uteroplacental cDNA microarray, and (3) to study the roles of molecules involved in endometrial remodeling. Bovine trophoblastic binucleate cell-specific molecules, such as pregnancy-associated glycoproteins (PAGs), placental lactogen (PL), and prolactin-related proteins (PRPs), were markedly expressed in binucleate cells (BNCs) around implantation. The expression of PRP-1 was specific to the caruncular (CAR) area of the gravid uterine horn. Gelatinases (MMP-2 and -9) in association with heparanase may be central to endometrial remodeling. In situ hybridization analyses of PAGs, PRPs, PL, and heparanase suggested that BNCs expressed these molecules simultaneously. Future studies will further investigate the specific roles of these molecules in placentogenesis. The uteroplacental cDNA microarray presented cascades of molecular signatures not only for the endometrium but also for the intricate dialogue at the level of the feto-maternal interface in cattle. Placentome morphogenesis potentially parallels the dynamic multigenic circuitry and regulates the cell cycle in the endometrium. The roles of BNCs and their secreted molecules remain an enigma, particularly with regard to the adhesion process and endometrial remodeling, which is the focus of this study.