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We hypothesized that sexually dimorphic differences exist in the expression of miRNAs in amniotic fluid (AF) and maternal blood plasma (MP) in association with the process of sex determination and gonad differentiation in cattle. Amniotic fluid and MP were collected from six pregnant heifers (three carrying a single male and three a single female embryo) following slaughter on Day 39 postinsemination, coinciding with the peak of SRY expression. Samples (six AF and six MP) were profiled using an miRNA Serum/Plasma Focus PCR Panel. Differentially expressed (DE) miRNAs were identified in AF (n = 5) and associated MP (n = 56) of male vs. female embryos (P, Grant Support. Supported by Science Foundation Ireland (13/IA/1983) and grant RTI2018–093548-BI00 from the Spanish Ministry of Science and Innovation. IG-R was supported by a predoctoral fellowship from the Spanish Ministry of Science and Innovation (BES-2016-077794), and BP was supported by a Marie Sklodowska-Curie ITN European Joint Doctorate in Biology and Technology of Reproductive Health (REP-BIOTECH 675526).

Embryo transfer to the uterine horn contralateral to the ovary containing the corpus luteum (CL) negatively impacts pregnancy establishment in cattle. Our aim was to compare the transcriptome and ability of the ipsilateral and contralateral uterine horns to support preimplantation conceptus survival and growth to day 14. In experiment 1, endometrial samples from both horns were collected from synchronized heifers slaughtered on day 5, 7, 13, or 16 post-estrus (n = 5 per time) and subjected to RNA sequencing. In experiment 2, 10 day 7 in vitro produced blastocysts were transferred into the uterine horn ipsilateral (n = 9) or contralateral to the CL (n = 8) or into both horns (i.e., bilateral, n = 9) of synchronized recipient heifers. Reproductive tracts were recovered at slaughter on day 14, and the number and dimensions of recovered conceptuses were recorded for each horn. A total of 217, 54, 14, and 18 differentially expressed genes (>2-fold change, FDR P < 0.05) were detected between ipsilateral and contralateral horns on days 5, 7, 13, and 16, respectively, with signaling pathways regulating pluripotency of stem cells, ErbB signaling pathway, and mTOR signaling pathway amongst the top canonical pathways. Site of embryo transfer did not affect recovery rate (48.0%, 168/350) or length of conceptuses (mean ± SE 2.85 ± 0.27 mm). Although differences in gene expression exist between the endometrium of uterine horns ipsilateral and contralateral to the CL in cattle, they do not impact conceptus survival or length between day 7 and 14.Summary SentenceDifferences in endometrial gene expression exist between the ipsilateral and contralateral uterine horns in cattle, but conceptus growth to day 14 is not different between the horns.

SYNOPSIS. Studies in anhydrobiotic plants have defined many genes which are upregulated during desiccation, but comparable studies in invertebrates are at an early stage. To develop a better understanding of invertebrate anhydrobiosis, we have begun to characterise dehydration-inducible genes and their proteins in anhydrobiotic nematodes and bdelloid rotifers; this review emphasises recent findings with a hydrophilic nematode protein. Initial work with the fungivorous nematode Aphelenchus avenae led to the identification of two genes, both of which were markedly induced on slow drying (90‐98% relative humidity, 24 hr) and also by osmotic stress, but not by heat or cold or oxidative stresses. The first of these genes encodes a novel protein we have named anhydrin; it is a small, basic polypeptide, with no counterparts in sequence databases, which is predicted to be natively unstructured and highly hydrophilic. The second is a member of the Group 3 LEA protein family; this and other families of LEA proteins are widely described in plants, where they are most commonly associated with the acquisition of desiccation tolerance in maturing seeds. Like anhydrin, the nematode LEA protein, Aav-LEA-1, is highly hydrophilic and a recombinant form has been shown to be unstructured in solution. In vitro functional studies suggest that Aav-LEA-1 is able to stabilise other proteins against desiccation-induced aggregation, which is in keeping with a role of LEA proteins in anhydrobiosis. In vivo, however, Aav-LEA-1 is apparently processed into smaller forms during desiccation. A processing activity was found in protein extracts of dehydrated, but not hydrated, nematodes; these shorter polypeptides are also active anti-aggregants and we hypothesise that processing LEA protein serves to increase the number of active molecules available to the dehydrating animal. Other LEA-like proteins are being identified in nematodes and it seems likely therefore that they will play a major role in the molecular anhydrobiology of invertebrates, as they are thought to do in plants.

In mammals, successful pregnancy is dependent in part on the adaptation or regulation of the maternal immune system to prevent the rejection of the embryonic semiallograft. A modification in Th cell function and secretion is a requirement for the establishment and maintenance of pregnancy. Although there is strong evidence from studies in humans and mice linking successful pregnancy with the predominance of Th2-type immunity, the situation in cattle remains unclear. This study describes the characterization of the immune response of the bovine maternal endometrium to the presence of a developing embryo, with specific emphasis on the macrophage and dendritic cell populations and associated factors, using quantitative real-time PCR, in situ hybridization, and immunohistochemistry. Furthermore, in vivo and in vitro models were developed to investigate the potential role of progesterone and interferon-tau (IFNT) in the regulation of these immune factors. There was a marked increase in the population of CD14(+) cells and CD172a-CD11c(+) cells in the endometrium in response to pregnancy, which was paralleled by increased mRNA expression of a number of non-Th-associated factors, including IL12B and IL15, and downregulation of IL18. In addition, we identified several novel IFNT- and progesterone-regulated factors, including IL12B, MCP1, MCP2, PTX3, RSAD2, and TNFA, whose regulation may be critical to pregnancy outcome. Our findings give center stage to non-Th cells, such as monocytes/macrophages and dendritic cells, in the bovine immune response to the semiallogenic embryo. In conclusion, we propose that in cattle, successful pregnancy establishment is associated with a dramatic regulation of the cytokine network, primarily by endometrial monocytes/macrophages and dendritic cells.