Abstract
A proper balance of pro and anti-inflammatory cytokines at the fetal-maternal interface is crucial for successful embryo implantation and placental formation (placentation) during early gestation. However, mechanisms controlling this inflammatory profile are not well characterized. The C-X-C motif chemokine ligand 12 (CXCL12) and its receptor CXCR4 are expressed by fetal and maternal placental tissues and implicated in cytokine synthesis; roles of this axis during placentation are unclear. Using an in vivo sheep model, we demonstrated that suppressing CXCL12-CXCR4 signaling at the fetal-maternal interface during implantation results in dysregulated production of inflammatory cytokines in the placenta. The objective of the current study was to determine if the disrupted cytokine profile from suppressing CXCL12-CXCR4 signaling early in gestation would result in altered placental inflammatory profile at midgestation. On day 12 post-breeding, osmotic pumps were surgically installed in 37 ewes and delivered either CXCR4 inhibitor (AMD3100) at 1X dose, (n=8), 1.5X, (n=8), or 3X, (n=8) or saline (n=13) into the uterine lumen ipsilateral to the corpus luteum for 14 days. On days 90 and 135, placental tissues were collected, and maternal and fetal placenta components separated and analyzed. Gene expression for select cytokines were analyzed in the placenta using Real-time qPCR. On day 90, mRNA expression was significantly altered by AMD3100 treatment for tumor necrosis factor (TNF), interleukin 12 (IL-12), and transforming growth factor beta (TGFB) in fetal placenta. Expression of TGFB in fetal placenta was also altered by AMD3100 treatment compared to control on day 135 whereas IL-12 expression was significantly altered in maternal placenta on day 135. In conclusion, modulating CXCL12-induced actions is a novel approach to manipulating the fetal-maternal environment when most pregnancy losses occur. Increasing our understanding of CXCL12-induced actions controlling the placental inflammatory environment will hopefully reveal methods to improve reproductive success and fetal health in livestock.