Conceptus-derived prostaglandins regulate endometrial function in sheep

Global analyses and potential effects of extracellular vesicles on the establishment of conceptus implantation during the peri-implantation period

Intrauterine extracellular vesicles (EVs) are involved in establishing proper conceptus-endometrial communication, which is essential for conceptus implantation and subsequent successful placentation. Despite several studies on intrauterine EVs, the composition and quantitative changes in conceptus and endometrial EVs, as well as the effects of intrauterine EVs on endometrial epithelial cells (EECs) during the peri-implantation period, have not been well characterized. To elucidate global changes in proteins in EVs extracted from uterine flushings (UFs) during the pre-implantation (P17), just-implantation (P20), and post-implantation (P22) periods, the datasets of the proteome iTRAQ analysis were compared among P17, P20, and P22 EVs. These analyses revealed that the composition and function of proteins in the EVs changed dramatically during peri-implantation in cattle. Notably, intrauterine P17 EVs affected the high expression of "Developmental Biology" and "morphogenesis of an endothelium" compared with those in P20 and P22 EVs. Furthermore, P20 EVs had the functions of the high expression of "mitochondrial calcium ion homeostasis" and "Viral mRNA Translation" compared with those in P17 EVs. Transcripts extracted from EECs treated with P17, P20, or P22 EVs were subjected to RNA-seq analysis. These analyses identified 60 transcripts in EECs commonly induced by intrauterine EVs recovered from P17, P20, and P22, a large number of which were associated with "type I interferon signaling pathway". Collectively, these findings reveal the presence and multiple functions of EVs that are potentially implicated in facilitating conceptus implantation into the uterine epithelium during the peri-implantation period.

Transcriptome profiling analysis of uterus during chicken laying periods

The avian eggshell is formed in the uterus. Changes in uterine function may have a significant effect on eggshell quality. To identify the vital genes impacting uterine functional maintenance in the chicken, uteri in three different periods (22W, 31W, 51W) were selected for RNA sequencing and bioinformatics analysis. In our study, 520, 706 and 736 differentially expressed genes (DEGs) were respectively detected in the W31 vs W22 group, W51 vs W31 group and W51 vs W22 group. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated DEGs were enriched in the extracellular matrix, extracellular region part, extracellular region, extracellular matrix structural constituent, ECM receptor interaction, collagen-containing extracellular matrix and collagen trimer in the uterus (P < 0.05). Protein-protein interaction analysis revealed that FN1, LOX, THBS2, COL1A1, COL1A2, COL5A1, COL5A2, POSTN, MMP13, VANGL2, RAD54B, SPP1, SDC1, BTC, ANGPTL3 might be key candidate genes for uterine functional maintenance in chicken. This study discovered dominant genes and pathways which enhanced our knowledge of chicken uterine functional maintenance.

The ovine conceptus utilizes extracellular serine, glucose, and fructose to generate formate via the one carbon metabolism pathway

Highly proliferative cells rely on one carbon (1C) metabolism for production of formate required for synthesis of purines and thymidine for nucleic acid synthesis. This study was to determine if extracellular serine and/or glucose and fructose contribute the production of formate in ovine conceptuses. Suffolk ewes (n = 8) were synchronized to estrus, bred to fertile rams, and conceptuses were collected on Day 17 of gestation. Conceptuses were either snap frozen in liquid nitrogen (n = 3) or placed in culture in medium (n = 5) containing either: 1) 4 mM D-glucose + 2 mM [U-¹³C]serine; 2) 6 mM glycine + 4 mM D-glucose + 2 mM [U-¹³C]serine; 3) 4 mM D-fructose + 2 mM [U-¹³C]serine; 4) 6 mM glycine + 4 mM D-fructose + 2 mM [U-¹³C]serine; 5) 4 mM D-glucose + 4 mM D-fructose + 2 mM [U-¹³C]serine; or 6) 6 mM glycine + 4 mM D-glucose + 4 mM D-fructose + 2 mM [U-¹³C]serine. After 2 h incubation, conceptuses in their respective culture medium were homogenized and the supernatant analyzed for ¹²C- and ¹³C-formate by gas chromatography and amino acids by high performance liquid chromatography. Ovine conceptuses produced both ¹³C- and ¹²C-formate, indicating that the [U-¹³C]serine, glucose, and fructose were utilized to generate formate, respectively. Greater amounts of ¹²C-formate than ¹³C-formate were produced, indicating that the ovine conceptus utilized more glucose and fructose than serine to produce formate. This study is the first to demonstrate that both 1C metabolism and serinogenesis are active metabolic pathways in ovine conceptuses during the peri-implantation period of pregnancy, and that hexose sugars are the preferred substrate for generating formate required for nucleotide synthesis for proliferating trophectoderm cells.

Insulin-like growth factor system components expressed at the conceptus-maternal interface during the establishment of equine pregnancy

In many species, the insulin-like growth factors (IGF1 and IGF2), their receptors and IGF binding proteins play important roles in preparing the endometrium for implantation, and regulating conceptus growth and development. To determine whether the IGF system may contribute to conceptus-maternal interaction during equine pre-implantation development, we evaluated mRNA expression for IGF system components in conceptuses, and endometrium recovered from pregnant and cycling mares, on days 7, 14, 21 and 28 after ovulation. We also investigated expression of IGF1, IGF2 and their receptors 6 and 11 days after transfer of day 8 embryos to synchronous (day 8) or asynchronous (day 3) recipient mares. Expression of IGF1 and IGF2, IGF1R, IGF2R, INSR and IGFBPs 1, 2, 4 and 5 was evident in endometrium and conceptus membranes during days 7–28. Endometrial IGF2, INSR, IGFBP1 and IGFBP2 expression increased between days 7 and 28 of pregnancy. In conceptus membranes, expression of all IGF system components increased with developmental stage. Immunohistochemistry revealed strong expression of IGF1, IGF2 and IGF1R in both endometrium and conceptus membranes, whereas INSR was highly expressed in endometrium but barely detectable in the conceptus. Finally, a negatively asynchronous uterine environment retarded IGF1, IGF2 and INSR expression in the conceptus, whereas in the endometrium only INSR expression was altered by asynchrony. The presence of IGFs, their receptors and IGFBPs in the endometrium and conceptus during early equine pregnancy, and down-regulation in the conceptus following asynchronous embryo transfer, suggest a role in conceptus-maternal communication during the preparation for implantation.

Expression of Oxytocin/Neurophysin I and Oxytocinase in the Equine Conceptus from Day 8 to Day 21 Post-Ovulation

Leucyl and cystinyl aminopeptidase (LNPEP/oxytocinase) is an enzyme that metabolizes oxytocin in serum and tissues. The presence of oxytocin/neurophysin I (OXT), oxytocin and LNPEP and their relationship to other genes is unknown in the equine conceptus. Our objective was to characterize gene expression of LNPEP and OXT on D8, 10, 12, 14, 15, 16 and 21 conceptuses in relationship to other genes. Immunohistochemistry, western blot and liquid chromatography with tandem mass spectrometry (LC-MS/MS) were used for identification of oxytocin and LNPEP in D15, 16 and 18 conceptuses. LNPEP was increased at D15 compared to D10, was immunolocalized in the equine trophectoderm and endoderm, and protein was confirmed by LC-MS/MS. Maximal abundance of OXT was at D21, and lowest on D12 and D14, but no protein was identified. OXTR abundance was highest on D14 and D21. LNPEP was correlated with PTGFR and PTGES on D12 and D14-D15, and high expression of PTGES, PTGS2 was found on D14, D15 and D21; PTGFR was found on D8 and D12-21. LNPEP may have a role in prostaglandin regulation and conceptus fixation by decreasing the availability of oxytocin. Further investigation on the role embryonic LNPEP during pregnancy is warranted.

Cystatin M/E (Cystatin 6): A Janus-Faced Cysteine Protease Inhibitor with Both Tumor-Suppressing and Tumor-Promoting Functions

Alongside its contribution in maintaining skin homeostasis and its probable involvement in fetal and placental development, cystatin M/E (also known as cystatin 6) was first described as a tumor suppressor of breast cancer. This review aims to provide an update on cystatin M/E with particular attention paid to its role during tumorigenesis. Cystatin M/E, which is related to type 2 cystatins, displays the unique property of being a dual tight-binding inhibitor of both legumain (also known as asparagine endopeptidase) and cysteine cathepsins L, V and B, while its expression level is epigenetically regulated via the methylation of the CST6 promoter region. The tumor-suppressing role of cystatin M/E was further reported in melanoma, cervical, brain, prostate, gastric and renal cancers, and cystatin M/E was proposed as a biomarker of prognostic significance. Contrariwise, cystatin M/E could have an antagonistic function, acting as a tumor promoter (e.g., oral, pancreatic cancer, thyroid and hepatocellular carcinoma). Taking into account these apparently divergent functions, there is an urgent need to decipher the molecular and cellular regulatory mechanisms of the expression and activity of cystatin M/E associated with the safeguarding homeostasis of the proteolytic balance as well as its imbalance in cancer.

MMP9 and IGFBP1 Regulate Tumor Immune and Drive Tumor Progression in Clear Cell Renal Cell Carcinoma

Immunotherapy is a novel approach and has been used in various diseases, especially in cancers. Recently, immunotherapy has gradually been used to treat advanced clear cell renal cell carcinoma (ccRCC) or metastatic ccRCC. However, the efficacy of immunotherapy is not satisfying due to the influence of the tumor microenvironment. In this study, we mainly focused on the abundance and function of tumor-infiltrating immune cells (TIICs). Monocyte and TNM stage were identified as independent prognostic factors via CIBERSORT and Cox regression analysis. Then, ccRCC patients were divided into high risk/TNM^highMonocytes^low cluster and low risk/TNM^lowMonocytes^high cluster. Further differential gene analysis, protein-protein interaction (PPI) network, and survival analysis screened nine hub genes between the above two clusters. MMP9 and IGFBP1 were selected for further study through sample validation. Moreover, gene set enrichment analysis revealed that MMP9 and IGFBP1 were involved in tumor immune via mediating cell surface receptor signal pathway, cytokine production pathway, or monocyte signal pathway. In conclusion, these findings suggested that monocyte acted as a protective factor and MMP9/IGFBP1 played a vital role in tumor immune, which might become potential novel biomarkers and therapeutic targets for immunotherapy in ccRCC.

Asynchronous Embryo Transfer Followed by Comparative Transcriptomic Analysis of Conceptus Membranes and Endometrium Identifies Processes Important to the Establishment of Equine Pregnancy

Preimplantation horse conceptuses require nutrients and signals from histotroph, the composition of which is regulated by luteal progesterone and conceptus-secreted factors. To distinguish progesterone and conceptus effects we shortened the period of endometrial progesterone-priming by asynchronous embryo transfer. Day 8 embryos were transferred to synchronous (day 8) or asynchronous (day 3) recipients, and RNA sequencing was performed on endometrium and conceptuses recovered 6 and 11 days later (embryo days 14 and 19). Asynchrony resulted in many more differentially expressed genes (DEGs) in conceptus membranes (3473) than endometrium (715). Gene ontology analysis identified upregulation in biological processes related to organogenesis and preventing apoptosis in synchronous conceptuses on day 14, and in cell adhesion and migration on day 19. Asynchrony also resulted in large numbers of DEGs related to 'extracellular exosome'. In endometrium, genes involved in immunity, the inflammatory response, and apoptosis regulation were upregulated during synchronous pregnancy and, again, many genes related to extracellular exosome were differentially expressed. Interestingly, only 14 genes were differentially expressed in endometrium recovered 6 days after synchronous versus 11 days after asynchronous transfer (day 14 recipient in both). Among these, KNG1 and IGFBP3 were consistently upregulated in synchronous endometrium. Furthermore bradykinin, an active peptide cleaved from KNG1, stimulated prostaglandin release by cultured trophectoderm cells. The horse conceptus thus responds to a negatively asynchronous uterus by extensively adjusting its transcriptome, whereas the endometrial transcriptome is modified only subtly by a more advanced conceptus.

Bovine Viral Diarrhoea Virus Infection Disrupts Uterine Interferon Stimulated Gene Regulatory Pathways During Pregnancy Recognition in Cows

In cattle, conceptus-derived interferon tau (IFNT) is the pregnancy recognition (PR) signal. Our previous studies showed that non-cytopathic bovine viral diarrhoea virus (ncpBVDV) infection inhibited IFNT-induced interferon stimulated gene (ISG) expression, potentially causing early embryonic death. This study investigated the effect of bovine viral diarrhoea virus (BVDV) infection on upstream regulatory pathways of ISG production using an established PR model. Uterine endometrial cells from 10 apparently healthy and BVDV free cows were cultured and treated with 0 or 100 ng/mL IFNT for 24 h in the presence or absence of ncpBVDV infection. Microarray and pathway analysis were used to determine the IFNT-induced upstream regulators. Expression of the genes associated with the identified pathways were quantified with qPCR. IFNT challenge activated the signalling pathways associated with IFN receptors, JAK1/TYK2, IRFs and STATs and ncpBVDV infection inhibited the activation of IFNT on this pathway. Inhibition of this upstream signalling pathway may thus reduce ISG production to disrupt maternal PR. In addition, the reduction of uterine immunity by ncpBVDV infection may predispose the animals to uterine infection, which in turn impairs their reproductive performance. This provides a mechanism of how BVDV infection leads to early pregnancy failure in cows.

Prostaglandin-endoperoxide synthase 2 is not required for preimplantation ovine conceptus development in sheep

Conceptus development and elongation is required for successful pregnancy establishment in ruminants and is coincident with the production of interferon τ (IFNT) and prostaglandins (PGs). In both the conceptus trophectoderm and endometrium, PGs are primarily synthesized through a prostaglandin-endoperoxide synthase 2 (PTGS2) pathway and modify endometrial gene expression and thus histotroph composition in the uterine lumen to promote conceptus growth and survival. Chemical inhibition of PG production by both the endometrium and the conceptus prevented elongation in sheep. However, the contributions of conceptus-derived PGs to preimplantation conceptus development remain unclear. In this study, CRISPR-Cas9 genome editing was used to inactivate PTGS2 in ovine embryos to determine the role of PTGS2-derived PGs in conceptus development and elongation. PTGS2 edited conceptuses produced fewer PGs, but secreted similar amounts of IFNT to their Cas9 control counterparts and elongated normally. Expression of PTGS1 was lower in PTGS2 edited conceptuses, but PPARG expression and IFNT secretion were unaffected. Content of PGs in the uterine lumen was similar as was gene expression in the endometrium of ewes who received either Cas9 control or PTGS2 edited conceptuses. These results support the idea that intrinsic PTGS2-derived PGs are not required for preimplantation embryo or conceptus survival and development in sheep.

Single Nucleotide Polymorphisms in SLC5A1, CCNA1, and ABCC1 and the Association with Litter Size in Small-Tail Han Sheep

Simple Summary

Litter size is one of the most important reproductive traits in sheep. Four single nucleotide polymorphisms (SNPs), g.70067210 T > C in SLC5A1, g.25350431 C > T and g.25360220 T > C in CCNA1, and g.14413132 C > T in ABCC1, were identified by mass spectrometry and may be associated with litter size in sheep. Four SNPs were genotyped in Small-Tail Han, Hu, Cele Black, Suffolk, Sunite, Prairie Tibetan, and Tan sheep, and the expression patterns of SLC5A1, CCNA1, and ABCC1 were determined in Small-Tail Han sheep with different fecundities. Furthermore, we also studied the FecB mutation’s association with litter size in Small-Tail Han sheep. The results indicated that all genes included in this study were differentially expressed in the ovary and uterus of polytocous and monotocous Small-Tail Han sheep. Furthermore, association analysis indicated that both g.70067210 T > C in SLC5A1 and the FecB mutation in BMPR-IB were significantly associated with litter size in Small-Tail Han sheep. Linear regression analysis of the association of multiple markers (FecB and g.70067210 T > C in SCL5A1) with litter size indicated that homozygous ewes carrying the BB/TT genotype had a larger litter size than any other genotype.

Abstract

SLC5A1, CCNA1, and ABCC1 have been extensively studied as candidate genes because of their great influence on the reproductive traits of animals. However, little is known about the association between polymorphisms of the SLC5A1, CCNA1, and ABCC1 genes and litter size in Small-Tail Han sheep. In this study, the expression levels of SLC5A1, CCNA1, and ABCC1 in HPG (hypothalamic–pituitary–gonadal) axis tissues of polytocous and monotocous Small-Tail Han sheep were analyzed by qPCR. To better understand the effects of four single nucleotide polymorphisms (SNPs) comprising of g.70067210 T > C in SLC5A1, g.25350431 C > T and g.25360220 T > C in CCNA1, and g.14413132 C > T in ABCC1, a population genetic analysis was conducted using data obtained from genotyping in 728 sheep from seven breeds. The results indicated that all genes included in this study were differentially expressed in the pituitary and uterus of polytocous and monotocous Small-Tail Han sheep (p < 0.05). The associations of these four SNPs and the FecB mutation with litter size in 384 Small-Tail Han sheep were analyzed, therefore, and it was found that both g.70067210T > C and the FecB mutation were significantly associated with litter size (p < 0.05). The linear regression analysis of the association of multiple markers (FecB and g.70067210 T > C in SCL5A1) with litter size indicated that homozygous ewes carrying the BB/TT genotype had larger litter size than any ewes with any other genotype. In conclusion, the SLC5A1 SNPs significantly affect litter size in sheep and are useful as genetic marker for litter size.

Prostaglandin F2α (PGF2α) production possibility and its receptors expression in the early- and late-cleaved preimplantation bovine embryos

BACKGROUND

Prostaglandin F_2α (PGF_2α) is an important component for the physiology of female reproductive processes. In the literature, the data pertaining to the synthesis and action of PGF_2α in early embryonic bovine development are limited. In our study, we used the bovine in vitro culture model based on the time of first cleavage to determine the mRNA expression and immunolocalization of PGF_2α synthase and its receptor in bovine embryos from the 2-cell stage to the hatched blastocyst stage. We also evaluated PGF_2α production at 2, 5 and 7 days of in vitro culture.

RESULTS

We found a significantly higher proportion of blastocysts obtained from the early-cleaved embryos than from the late-cleaved embryos (37.7% vs. 26.1% respectively, P < 0.05). The PGFS mRNA expression was significantly higher in the late-cleaved group than in the early-cleaved group at the 2-, 4- and 16-cell stages (P < 0.05). For PTGFR, we observed that within the late-cleaved group, the mRNA abundance was significantly higher in embryos at the 2- and 16-cell stages than in embryos at the 4- and 8-cell stages (P < 0.05). We observed that PTGFR mRNA expression was significantly higher in the 2- and 16-cell embryos in the late-cleaved group than that in the early-cleaved group embryos (P < 0.05). Among the blastocysts, the PGFS and PTGFR expression levels showed a trend towards higher mRNA expression in the late-cleaved group than in the early-cleaved group. Analysis of PGF_2α production showed that within the early-cleaved group, the content of PGF_2α in the in vitro culture medium was significantly higher on day 7 than it was on day 2 (P < 0.05).

CONCLUSIONS

The mRNA expression levels of PGF_2α synthase and its receptor depend on the developmental stage and the embryo quality. Analyses of PGFS and PTGFR expression in bovine blastocysts and of PGF_2α embryo production suggest that prostaglandin F_2α can act in an autocrine and paracrine manner in bovine in vitro-produced preimplantation embryos. Moreover, the tendency of PTGFR and PGFS mRNA expression to be upregulated in embryos with low developmental potential can indicate a compensation mechanism related to high PGFS and PTGFR mRNA expression levels in low-quality embryos.

ASCT2 regulates glutamine uptake and cell growth in endometrial carcinoma

Glutamine commonly becomes a conditionally essential amino acid in cancer. Glutamine is supplied to the cell by transporters such as ASCT2 (SLC1A5), which is frequently upregulated in multiple cancers. Here we investigated the expression of ASCT2 in endometrial carcinoma, and evaluated the contribution of ASCT2 to glutamine uptake and endometrial cancer cell growth. Analysis of human gene expression data showed that ASCT2 was significantly upregulated in both endometrioid and serous subtypes of endometrial carcinoma, compared to normal, age-matched endometrium. Furthermore, immunohistochemical staining of primary human endometrioid adenocarcinomas showed that tumours stain positive for ASCT2 in either a uniform or mosaic expression pattern, while normal adjacent glands appeared predominantly negative for ASCT2 staining. Chemical inhibition of glutamine transport by benzylserine or GPNA led to a significant decrease in endometrial cancer cell growth and spheroid cross-sectional area. ASCT2 knockdown recapitulated the decrease of cell growth and spheroid cross-sectional area in HEC1A cells, suggesting a reliance on ASCT2-mediated glutamine uptake. ASCT2 knockdown in Ishikawa cells led to lower glutamine uptake and cell growth, but did not affect spheroid area. Ishikawa cells express higher levels of the glutamine transporter SNAT1 compared to HEC1A cells, suggesting these cells may rely on both ASCT2 and SNAT1 for glutamine uptake. Since SNAT1 is also significantly upregulated in the endometrioid and serous subtypes, these data indicate that ASCT2 and SNAT1 could be used as markers of malignancy, and/or potential therapeutic targets in patients with endometrial carcinoma.

Role of progesterone in embryo development in cattle

Progesterone (P4) from the corpus luteum is critical for the establishment and maintenance of pregnancy and plays a major role in regulating endometrial secretions essential for stimulating and mediating changes in conceptus growth and differentiation throughout early pregnancy in ruminants. Numerous studies have demonstrated an association between elevated systemic P4 and acceleration in conceptus elongation. A combination of in vivo and in vitro experiments found that the effects of P4 on conceptus elongation are indirect and mediated through P4-induced effects in the endometrium. Despite effects on elongation, data on the effects of post-insemination supplementation with P4 on pregnancy rates are conflicting. This review highlights the effects of P4 on conceptus development and examines strategies that have been undertaken to manipulate P4 concentrations to increase fertility.

Insights into conceptus elongation and establishment of pregnancy in ruminants

This review integrates established and new information on the factors and pathways regulating conceptus–endometrial interactions, conceptus elongation and establishment of pregnancy in sheep and cattle. Establishment of pregnancy in domestic ruminants begins at the conceptus stage (embryo or fetus and associated extra-embryonic membranes) and includes pregnancy recognition signalling, implantation and the onset of placentation. Survival and growth of the preimplantation blastocyst and elongating conceptus require embryotrophic factors (amino acids, carbohydrates, proteins, lipids and other substances) provided by the uterus. The coordinated and interactive actions of ovarian progesterone and conceptus-derived factors (interferon-τ and prostaglandins) regulate expression of elongation- and implantation-related genes in the endometrial epithelia that alter the uterine luminal milieu and affect trophectoderm proliferation, migration, attachment, differentiation and function. A comparison of sheep and cattle finds both conserved and non-conserved embryotrophic factors in the uterus; however, the overall biological pathways governing conceptus elongation and establishment of pregnancy are likely conserved. Given that most pregnancy losses in ruminants occur during the first month of pregnancy, increased knowledge is necessary to understand why and provide a basis for new strategies to improve pregnancy outcome and reproductive efficiency.

Preattachment Embryos of Domestic Animals: Insights into Development and Paracrine Secretions

In mammalian species, endometrial receptivity is driven by maternal factors independently of embryo signals. When pregnancy initiates, paracrine secretions of the preattachment embryo are essential both for maternal recognition and endometrium preparation for implantation and for coordinating development of embryonic and extraembryonic tissues of the conceptus. This review mainly focuses on domestic large animal species. We first illustrate the major steps of preattachment embryo development, including elongation in bovine, ovine, porcine, and equine species. We next highlight conceptus secretions that are involved in the communication between extraembryonic and embryonic tissues, as well as between the conceptus and the endometrium. Finally, we introduce experimental data demonstrating the intimate connection between conceptus secretions and endometrial activity and how adverse events perturbing this interplay may affect the progression of implantation that will subsequently impact pregnancy outcome, postnatal health, and expression of production traits in livestock offspring.

Morphologic and transcriptomic assessment of bovine embryos exposed to dietary long-chain fatty acids

The main objectives of this study were to determine the influence of diets enriched in α-linolenic, linoleic or oleic acid on the development and transcriptomic profile of embryos collected from dairy cattle. Non-lactating Holstein cows received one of the three diets supplemented with 8% rolled oilseeds: flax (FLX, n = 8), sunflower (SUN, n = 7) or canola (CAN, n = 8). After a minimum 35-day diet adaptation, cows were superovulated, artificially inseminated and ova/embryos recovered non-surgically after 7.5 days. Cows fed FLX had less degenerated embryos and more viable embryos than those fed CAN or SUN. In total, 175 genes were differentially expressed in blastocysts from cows fed FLX than in cows fed CAN or SUN. These differentially expressed genes were mainly involved in cellular growth and proliferation, cellular development, and cell survival and viability. In conclusion, dietary n-3 polyunsaturated fatty acids reduced early embryonic degeneration possibly through improving embryonic cell survival and viability.

Role of lipids on elongation of the preimplantation conceptus in ruminants

Elongation of the preimplantation conceptus is a prerequisite for successful pregnancy in ruminants and depends on histotroph secretion by the endometrium. Lipids are an essential component of the histotroph, and recent studies indicate that lipids have important roles in the elongation phase of conceptus development. The onset of elongation is marked by dynamic changes in the transcriptome of trophectoderm cells, which are associated with lipid metabolism. During elongation, the trophectoderm increases transcript expression of genes related to uptake, metabolism andde novobiosynthesis of fatty acids and prostaglandins. Expression of the genePPARGincreases substantially, and activation of the transcription factor PPARG by binding of lipid ligands appears to be crucial for the coordination of cell biology during elongation. Lipids accumulated in the epithelial cells of the endometrium during diestrus are likely the most important source of fatty acids for utilization by the conceptus and become available in the uterine lumen through exporting of exosomes, microvesicles, carrier proteins and lipoproteins. Targeting of uterine lipid metabolism and PPARG activity during preimplantation conceptus development through nutraceutical diets may be a good strategy to improve pregnancy survival and reproductive efficiency in ruminants.

Determinant molecular markers for peri-gastrulating bovine embryo development

Peri-gastrulation defines the time frame between blastocyst formation and implantation that also corresponds in cattle to elongation, pregnancy recognition and uterine secretion. Optimally, this developmental window prepares the conceptus for implantation, placenta formation and fetal development. However, this is a highly sensitive period, as evidenced by the incidence of embryo loss or early post-implantation mortality after AI, embryo transfer or somatic cell nuclear transfer. Elongation markers have often been used within this time frame to assess developmental defects or delays, originating either from the embryo, the uterus or the dam. Comparatively, gastrulation markers have not received great attention, although elongation and gastrulation are linked by reciprocal interactions at the molecular and cellular levels. To make this clearer, this peri-gastrulating period is described herein with a focus on its main developmental landmarks, and the resilience of the landmarks in the face of biotechnologies is questioned.

Select nutrients and their effects on conceptus development in mammals

The dialogue between the mammalian conceptus (embryo/fetus and associated membranes) involves signaling for pregnancy recognition and maintenance of pregnancy during the critical peri-implantation period of pregnancy when the stage is set for implantation and placentation that precedes fetal development. Uterine epithelial cells secrete and/or transport a wide range of molecules, including nutrients, collectively referred to as histotroph that are transported into the fetal-placental vascular system to support growth and development of the conceptus. The availability of uterine-derived histotroph has long-term consequences for the health and well-being of the fetus and the prevention of adult onset of metabolic diseases. Histotroph includes numerous amino acids, but arginine plays a particularly important role as a source of nitric oxide and polyamines required for fetal-placental development in rodents, swine and humans through mechanisms that remain to be fully elucidated. Mechanisms whereby arginine regulates expression of genes via the mechanistic target of rapamycin cell signaling pathways critical to conceptus development, implantation and placentation are discussed in detail in this review.

Conceptus elongation in ruminants: roles of progesterone, prostaglandin, interferon tau and cortisol

The majority of pregnancy loss in ruminants occurs during the first three weeks after conception, particularly during the period of conceptus elongation that occurs prior to pregnancy recognition and implantation. This review integrates established and new information on the biological role of ovarian progesterone (P4), prostaglandins (PGs), interferon tau (IFNT) and cortisol in endometrial function and conceptus elongation. Progesterone is secreted by the ovarian corpus luteum (CL) and is the unequivocal hormone of pregnancy. Prostaglandins (PGs) and cortisol are produced by both the epithelial cells of the endometrium and the trophectoderm of the elongating conceptus. In contrast, IFNT is produced solely by the conceptus trophectoderm and is the maternal recognition of pregnancy signal that inhibits production of luteolytic pulses of PGF_2α by the endometrium to maintain the CL and thus production of P4. Available results in sheep support the idea that the individual, interactive, and coordinated actions of P4, PGs, IFNT and cortisol regulate conceptus elongation and implantation by controlling expression of genes in the endometrium and/or trophectoderm. An increased knowledge of conceptus-endometrial interactions during early pregnancy in ruminants is necessary to understand and elucidate the causes of infertility and recurrent early pregnancy loss and provide new strategies to improve fertility and thus reproductive efficiency.

Uterine responses to the preattachment embryo in domestic ungulates: recognition of pregnancy and preparation for implantation

The endometrium is a tissue newly evolved with the development of mammalian species. Its main function is the support of embryonic growth and development and the nutrition of the fetus. The species-specific differences in establishment and maintenance of pregnancy make the study of this tissue in various mammalian organisms particularly interesting. With the application of omics technologies to various mammalian species, many systematic studies of endometrial gene expression changes during the phase of establishment of pregnancy have been performed to obtain a global view of regulatory events associated with this biological process. This review summarizes the results of trancriptome studies of bovine, porcine, and equine endometrium. Furthermore, the results are compared between these species and to humans. Because an increasing number of studies suggest an important role of small regulatory RNAs (i.e., microRNAs), recent findings related to the regulation of endometrial functions and the development of the conceptus are presented.

Amino acids in the uterine luminal fluid reflects the temporal changes in transporter expression in the endometrium and conceptus during early pregnancy in cattle

In cattle, conceptus-maternal interactions are critical for the establishment and maintenance of pregnancy. A major component of this early interaction involves the transport of nutrients and secretion of key molecules by uterine epithelial cells to help support conceptus development during the peri-implantation period of pregnancy. Objectives were to: 1) analyze temporal changes in the amino acid (AA) content of uterine luminal fluid (ULF) during the bovine estrous cycle; 2) understand conceptus-induced alterations in AA content; 3) determine expression of AA transporters in the endometrium and conceptus; and 4) determine how these transporters are modulated by (Progesterone) P4. Concentrations of aspartic acid, arginine, glutamine, histidine, lysine, isoleucine, leucine, phenylalanine and tyrosine decreased on Day 16 of the estrous cycle but increased on Day 19 in pregnant heifers (P<0.05). Glutamic acid only increased in pregnant heifers on Day 19 (P<0.001). Asparagine concentrations were greater in ULF of cyclic compared to pregnant heifers on Day 7 (P<0.05) while valine concentrations were higher in pregnant heifers on Day 16 (P<0.05). Temporal changes in expression of the cationic AA transporters SLC7A1 SLC7A4 and SLC7A6 occurred in the endometrium during the estrous cycle/early pregnancy coordinate with changes in conceptus expression of SLC7A4, SLC7A2 and SLC7A1 (P<0.05). Only one acidic AA transporter (SLC1A5) increased in the endometrium while conceptus expression of SLC1A4 increased (P<0.05). The neutral AA transporters SLC38A2 and SLC7A5 increased in the endometrium in a temporal manner while conceptus expression of SLC38A7, SLC43A2, SLC38A11 and SLC7A8 also increased (P<0.05). P4 modified the expression of SLC1A1, -1A4, -1A5, -38A2, -38A4, -38A7, -43A2, -6A14, -7A1, -7A5 and -7A7 in the endometrium. Results demonstrate that temporal changes in AA in the ULF reflect changes in transporter expression in the endometrium and conceptus during early pregnancy in cattle, some of which are modified by P4.

Conceptus-derived prostaglandins regulate gene expression in the endometrium prior to pregnancy recognition in ruminants

In cattle, the blastocyst hatches from the zona pellucida on days 8-9 and then forms a conceptus that grows and elongates into an ovoid and then filamentous shape between days 9 and 16. The growing conceptus synthesizes and secretes prostaglandins (PGs) and interferon τ (IFNT). Our hypothesis was that the ovoid conceptus exerts a local effect on the endometrium prior to maternal recognition of pregnancy on day 16 in cattle. In study one, synchronized cyclic heifers received no blastocysts or 20 in vitro-produced blastocysts on day 7 and their uteri were collected on day 13. IFNT was not detected by RIA in the uterine flushing samples of pregnant heifers containing multiple ovoid conceptuses; however, total PG levels were higher in the uterine lumen of pregnant heifers than in that of cyclic heifers. Microarray analysis revealed that the expression of 44 genes was increased in the endometria of day 13 pregnant heifers when compared with that in the endometria of cyclic heifers, and many of these genes were classical Type I IFN-stimulated genes (ISGs). In studies two and three, the effects of infusing PGs at the levels produced by the elongating day 14 conceptus into the uterine lumen of cyclic ewes on ISG expression in the endometrium were determined. Results indicated that the infusion of PGs increased the abundance of several ISGs in the endometrium. These studies support the hypothesis that the day 13 conceptus secretes PGs that act locally in a paracrine manner to alter gene expression in the endometrium prior to pregnancy recognition in cattle.

Hosting the preimplantation embryo: potentials and limitations of different approaches for analysing embryo - endometrium interactions in cattle

Ongoing detailed investigations into embryo–maternal communication before implantation reveal that during early embryonic development a plethora of events are taking place. During the sexual cycle, remodelling and differentiation processes in the endometrium are controlled by ovarian hormones, mainly progesterone, to provide a suitable environment for establishment of pregnancy. In addition, embryonic signalling molecules initiate further sequences of events; of these molecules, prostaglandins are discussed herein as specifically important. Inadequate receptivity may impede preimplantation development and implantation, leading to embryonic losses. Because there are multiple factors affecting fertility, receptivity is difficult to comprehend. This review addresses different models and methods that are currently used and discusses their respective potentials and limitations in distinguishing key messages out of molecular twitter. Transcriptome, proteome and metabolome analyses generate comprehensive information and provide starting points for hypotheses, which need to be substantiated using further confirmatory methods. Appropriate in vivo and in vitro models are needed to disentangle the effects of participating factors in the embryo–maternal dialogue and to help distinguish associations from causalities. One interesting model is the study of somatic cell nuclear transfer embryos in normal recipient heifers. A multidisciplinary approach is needed to properly assess the importance of the uterine milieu for embryonic development and to use the large number of new findings to solve long-standing issues regarding fertility.

Gene expression analysis in human breast cancer associated blood vessels

Angiogenesis is essential for solid tumour growth, whilst the molecular profiles of tumour blood vessels have been reported to be different between cancer types. Although presently available anti-angiogenic strategies are providing some promise for the treatment of some cancers it is perhaps not surprisingly that, none of the anti-angiogenic agents available work on all tumours. Thus, the discovery of novel anti-angiogenic targets, relevant to individual cancer types, is required. Using Affymetrix microarray analysis of laser-captured, CD31-positive blood vessels we have identified 63 genes that are upregulated significantly (5-72 fold) in angiogenic blood vessels associated with human invasive ductal carcinoma (IDC) of the breast as compared with blood vessels in normal human breast. We tested the angiogenic capacity of a subset of these genes. Genes were selected based on either their known cellular functions, their enriched expression in endothelial cells and/or their sensitivity to anti-VEGF treatment; all features implicating their involvement in angiogenesis. For example, RRM2, a ribonucleotide reductase involved in DNA synthesis, was upregulated 32-fold in IDC-associated blood vessels; ATF1, a nuclear activating transcription factor involved in cellular growth and survival was upregulated 23-fold in IDC-associated blood vessels and HEX-B, a hexosaminidase involved in the breakdown of GM2 gangliosides, was upregulated 8-fold in IDC-associated blood vessels. Furthermore, in silico analysis confirmed that AFT1 and HEX-B also were enriched in endothelial cells when compared with non-endothelial cells. None of these genes have been reported previously to be involved in neovascularisation. However, our data establish that siRNA depletion of Rrm2, Atf1 or Hex-B had significant anti-angiogenic effects in VEGF-stimulated ex vivo mouse aortic ring assays. Overall, our results provide proof-of-principle that our approach can identify a cohort of potentially novel anti-angiogenic targets that are likley to be, but not exclusivley, relevant to breast cancer.