Luman recruiting factor is involved in stromal cell proliferation during decidualization in mice.

Decidualization is crucial for successful pregnancy in mice and humans. Although many essential molecular modulators have been identified during decidualization, the precise molecular mechanism of uterine decidualization remains largely unknown. Our previous research indicates that luman recruiting factor (LRF) is strongly expressed in decidual uteri of mice on days 6-8 of pregnancy. In this study, our aim is to determine the biological functions of LRF during decidualization in mice. We used the shLRF lentivirus to attenuate the expression of LRF, which significantly reduced the weight and size of implantation sites on days 7-8 of pregnancy. In a stromal cell culture model, LRF mRNA and protein levels increased significantly during stromal cell decidualization induced by estrogen and progesterone. LRF silencing resulted in the decidual markers decidual prolactin-related protein, insulin-like growth factor-binding protein 1 and progesterone receptor being dramatically reduced, and the decidual process was significantly inhibited. Cell-cycle analysis and cell apoptosis analysis revealed that, although no obvious apoptosis occurred in shLRF-lentivirus-infected stromal cells during decidualization, proliferation was inhibited via S-phase cell-cycle arrest, and the mitotic activity of uterine stromal cells was inhibited. An examination of cell-cycle regulatory factors indicated that the mRNA expression levels of cyclin A and cyclin B1 were significantly down-regulated after treatment with shLRF lentivirus. Thus, LRF seems to be involved in the regulation of decidualization during pregnancy by modulating the expression of the key cell-cycle regulatory factors cyclin A and cyclin B1.