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Puberty is a complex physiological event by which animals mature into an adult capable of sexual reproduction. In order to enhance our understanding of the genes and regulatory pathways and networks involved in puberty, we characterized the transcriptome of five reproductive tissues (i.e. hypothalamus, pituitary gland, ovary, uterus, and endometrium) as well as tissues known to be relevant to growth and metabolism needed to achieve puberty (i.e., longissimus dorsi muscle, adipose, and liver). These tissues were collected from pre- and post-pubertal Brangus heifers (3/8 Brahman; Bos indicus x 5/8 Angus; Bos taurus) derived from a population of cattle used to identify quantitative trait loci associated with fertility traits (i.e., age of first observed corpus luteum (ACL), first service conception (FSC), and heifer pregnancy (HPG)). In order to exploit the power of complementary omics analyses, pre- and post-puberty co-expression gene networks were constructed by combining the results from genome-wide association studies (GWAS), RNA-Seq, and bovine transcription factors. Eight tissues among pre-pubertal and post-pubertal Brangus heifers revealed 1,515 differentially expressed and 943 tissue-specific genes within the 17,832 genes confirmed by RNA-Seq analysis. The hypothalamus experienced the most notable up-regulation of genes via puberty (i.e., 204 out of 275 genes). Combining the results of GWAS and RNA-Seq, we identified 25 loci containing a single nucleotide polymorphism (SNP) associated with ACL, FSC, and (or) HPG. Seventeen of these SNP were within a gene and 13 of the genes were expressed in uterus or endometrium. Multi-tissue omics analyses revealed 2,450 co-expressed genes relative to puberty. The pre-pubertal network had 372,861 connections whereas the post-pubertal network had 328,357 connections. A sub-network from this process revealed key transcriptional regulators (i.e., PITX2, FOXA1, DACH2, PROP1, SIX6, etc.). Results from these multi-tissue omics analyses improve understanding of the number of genes and their complex interactions for puberty in cattle.

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. [ABSTRACT FROM AUTHOR]

Problem: Chemokines help coordinate inflammation within the fetal‐maternal microenvironment during gestation. The chemokine CXCL12 signaling through its receptor CXCR4 regulates inflammatory activity, but this phenomenon is not well understood during pregnancy, and there are no reports exploring the role of this pair in peripheral immune tolerance during gestation. Herein, we hypothesize that intrauterine CXCL12‐CXCR4 signaling governs local and systemic immunomodulatory dynamics during early gestation in ewes. Method of study: Osmotic pumps were surgically installed for intrauterine infusion of a CXCR4 inhibitor, AMD3100, beginning on day 12 post‐breeding in sheep. Endometrial tissues were collected on day 35 of gestation and evaluated for inflammatory potential, Akt pathway activation, and autophagy induction. Demonstrative of peripheral immune activity, levels of select cytokines were assessed in daily blood samples collected throughout the study, as well as in corpus luteum and spleen on day 35. Results: Anti‐inflammatory IL10 was primarily localized to endometrial glandular epithelium with lower abundance when CXCR4 was antagonized. Inhibition of CXCR4 at the fetal‐maternal interface resulted in less activation of Akt in endometrium, while evidence of autophagy induction was greater. Corpora lutea from ewes receiving intrauterine AMD3100 exhibited lower interferon‐gamma (IFNG) expression. Blood inflammatory potential was differentially altered in a temporal fashion throughout infusion. IL10 abundance in spleen was greater following CXCR4 inhibition at the fetal‐maternal interface, while IFNG was less. Conclusion: Intrauterine CXCL12‐CXCR4 signaling governs endometrial and systemic inflammation; disruption of this axis may have detrimental impacts on offspring and maternal health. [ABSTRACT FROM AUTHOR]