PS-2 Early Intrauterine Suppression of CXCL12-CXCR4 Alters Expression of Placental Inflammatory Profile at Mid-to-Late Gestation

Abstract

Abstract A proper balance of inflammatory cytokines at the fetal-maternal interface is crucial for successful embryo implantation and placental formation. Chemokine ligand 12 (CXCL12) and receptor CXCR4 are expressed by fetal and maternal placental tissues and implicated in cytokine synthesis. However, mechanisms controlling the axis and placental inflammatory profile are not well characterized. Using an in-vivo sheep model, we previously demonstrated suppressing CXCL12-CXCR4 signaling at the fetal-maternal interface during implantation yielded dysregulated production of inflammatory cytokines in the placenta. Our objective was to determine if disrupting the cytokine profile during implantation alters the placental inflammatory profile at mid-to-late gestation. Day 12 post-breeding, osmotic pumps were surgically installed in 37 ewes to deliver CXCR4 inhibitor (1.5X dose, n = 8; 1X dose, n = 8; 3X dose, n = 8) or saline (n = 13) into the uterine lumen ipsilateral to the corpus luteum for 14 days. On days 90 and 135 of gestation, placental tissues were collected; maternal (caruncle) and fetal (cotyledon) placenta components were then separated and analyzed. Real-time qPCR was used to measure gene expression of pro-inflammatory cytokines tumor necrosis factor (TNF), interferon-γ (IFNγ), interleukin-12 (IL12), and anti-inflammatory cytokines interleukin-10 (IL10) and transforming growth factor-β (TGFβ). Gene expression for TGFβ from tissues ipsilateral to the pump on day 90 increased (P < 0.03) in caruncles from 3x treated ewes compared to control ewes while IL10 mRNA decreased (P < 0.02) in cotyledons from 1.5x compared to 3x treatment. Furthermore, analysis of day 135 1x treated ewes showed greater expression (P < 0.03) of IL12 in caruncles ipsilateral compared to contralateral of the pump; meanwhile IL10 showed decreased expression (P < 0.02) in cotyledons ipsilateral compared to contralateral of the pump. High levels of TGFβ, IFNγ (whose production is promoted by increased IL12), and TNF along with decreased levels of IL10 have been associated with preeclampsia in women. The changes in gene expressions of ovine immune cytokines with a disrupted CXCL12-CCR4 axis may be related to preeclamptic events. Ultimately, modulating CXCL12-induced actions is a novel approach to manipulating the fetal-maternal environment when most pregnancy losses occur and may reveal methods to improve reproductive success and fetal health in livestock.