Establishment of implantation in pig is accompanied by a coordinated interaction between the maternal uterine endometrium and conceptus development. We investigated the expression profiles of endometrial tissue on Days 9, 12 and 15 of pregnancy and on Day 12 of non-pregnancy in Yorkshire, and performed a comprehensive analysis of long non-coding RNAs (lncRNAs) in endometrial tissue samples by using RNA sequencing. As a result, 2805 novel lncRNAs, 2,376 (301 lncRNA and 2075 mRNA) differentially expressed genes (DEGs) and 2149 novel transcripts were obtained by pairwise comparison. In agreement with previous reports, lncRNAs shared similar characteristics, such as shorter in length, lower in exon number, lower at expression level and less conserved than protein coding transcripts. Bioinformatics analysis showed that DEGs were involved in protein binding, cellular process, immune system process and enriched in focal adhesion, Jak-STAT, FoxO and MAPK signaling pathway. We also found that lncRNAs TCONS_01729386 and TCONS_01325501 may play a vital role in embryo pre-implantation. Furthermore, the expression of FGF7, NMB, COL5A3, S100A8 and PPP1R3D genes were significantly up-regulated at the time of maternal recognition of pregnancy (Day 12 of pregnancy). Our results first identified the characterization and expression profile of lncRNAs in pig endometrium during pre-implantation phases.

/pdf/analyses-of-long-non-coding-rna-and-mrna-profiling-using-rna-4j94uopr7s.pdf

Analyses of Long Non-Coding RNA and mRNA profiling using RNA sequencing during the pre-implantation phases in pig endometrium.

Background Thyroid hormone disorders and thyroid peroxidase autoantibodies (TPO-Ab) in women are associated with subfertility and early pregnancy loss. Here, we aim to provide a comprehensive overview of the literature on the pathophysiology of these associations. Methods A review of the literature in the English language was carried out. Relevant studies were identified by searching Medline, EMBASE and the Cochrane Controlled Trials Register from 1975 until March 2014. Results From a total of 6108 primary selected articles from the literature search, 105 articles were selected for critical appraisal. Observational data indicate that altered thyroid hormone levels are associated with disturbed folliculogenesis, spermatogenesis, lower fertilization rates and lower embryo quality. Triiodothyronine (T3) in combination with FSH enhances granulosa cell proliferation and inhibits granulosa cell apoptosis by the PI3K/Akt pathway. T3 is considered a biological amplifier of the stimulatory action of gonadotrophins on granulosa cell function. T3 increases the expression of matrix metalloproteinases (MMP), MMP-2, MMP-3, fetal fibronectin and integrin α5β1T3 in early placental extravillous trophoblasts. Thyroid hormone transporters and receptors are expressed in the ovary, early embryo, endometrium, uterus and placenta. No other data explaining the associations could be retrieved from the literature. The presence of TPO-Ab is negatively associated with spermatogenesis, fertilization and embryo quality, but no data are available on the potential pathophysiological mechanisms. Conclusions Thyroid hormone disorders and TPO-Ab are associated with disturbed folliculogenesis, spermatogenesis, fertilization and embryogenesis. The pathophysiology of these associations remains largely unknown, as evidence is limited and includes studies using small sample sizes, and often restricted to animal models. There are no studies on the pathophysiology underlying the association between TPO-Ab and reproduction. The available evidence, although limited, supports a role of thyroid hormone in fertility and early pregnancy. This justifies clinical intervention studies on the effects of thyroid hormone supplementation in women with subclinical hypothyroidism and in women prone to develop hypothyroidism due to the presence of TPO-Ab. In addition, more research is needed to identify the underlying mechanisms. This would be of particular interest in women undergoing IVF to pinpoint the effects of thyroid hormone on different parameters of reproduction.

/pdf/pathophysiological-aspects-of-thyroid-hormone-disorders-4xayf3halg.pdf

Pathophysiological aspects of thyroid hormone disorders/thyroid peroxidase autoantibodies and reproduction

Comparison of the timing of pig preimplantation development, alterations in the ultrastructure of embryonic germ layers, and cytological changes of the uterine epithelial cells leads to the supposition that a close relationship exists between embryonic and uterine development during early pregnancy. The results of in-vitro studies of embryonic development and of experiments concerning asynchrony between embryos and uterine environment confirm this supposition, especially as far as the post-hatching period is concerned. It is suggested that successive steps in embryonic germ layer differentiation may induce specific developmental events and secretory activity of the embryos. A mutual influence of maternal and embryonic tissues appears to exist, but we can only speculate about the causes of many of the described phenomena.

/pdf/embryonic-and-uterine-development-during-early-pregnancy-in-3ws7ojzpct.pdf

Embryonic and uterine development during early pregnancy in pigs

Context: Identifying novel molecular markers for assessing endometrial receptivity is necessary for understanding human implantation and may help in improving the clinical outcome of in vitro fertilization. Objective: We aimed to compare the gene expression profiles of the pre-receptive vs receptive phases of the natural cycle in human endometrial biopsies. Design: The design of this study was detecting the global gene expression profile of human endometrial receptivity by RNA-Seq. Setting: This study was conducted at a university reproductive center. Participants: Twelve women with normal menstrual cycles participated in the study. Intervention: Study interventions included endometrial biopsies. Main Outcome Measures: The endometrial transcriptomes were determined by RNA-Seq, and the expression of selected differentially expressed genes (DEGs) was validated by quantitative RT-PCR. Results: A total of 2372 DEGs were identified by RNA-Seq. Of these genes, 1099 were up-regulated at LH+7 versus LH+2, whereas...

Transcriptomic changes during the pre-receptive to receptive transition in human endometrium detected by RNA-Seq.

Viviparity (live birth) has evolved more than 150 times in vertebrates, and represents an excellent model system for studying the evolution of complex traits. There are at least 23 independent origins of viviparity in fishes, with syngnathid fishes (seahorses and pipefish) unique in exhibiting male pregnancy. Male seahorses and pipefish have evolved specialized brooding pouches that provide protection, gas exchange, osmoregulation, and limited nutrient provisioning to developing embryos. Pouch structures differ widely across the Syngnathidae, offering an ideal opportunity to study the evolution of reproductive complexity. However, the physiological and genetic changes facilitating male pregnancy are largely unknown. We used transcriptome profiling to examine pouch gene expression at successive gestational stages in a syngnathid with the most complex brood pouch morphology, the seahorse Hippocampus abdominalis. Using a unique time-calibrated RNA-seq data set including brood pouch at key stages of embryonic development, we identified transcriptional changes associated with brood pouch remodeling, nutrient and waste transport, gas exchange, osmoregulation, and immunological protection of developing embryos at conception, development and parturition. Key seahorse transcripts share homology with genes of reproductive function in pregnant mammals, reptiles, and other live-bearing fish, suggesting a common toolkit of genes regulating pregnancy in divergent evolutionary lineages.

https://www.zora.uzh.ch/id/eprint/120449/1/msv177.pdf

Seahorse Brood Pouch Transcriptome Reveals Common Genes Associated with Vertebrate Pregnancy

In pigs, conceptus attachment to the uterine surface epithelium starts around Day 14 of pregnancy preceded by a pronounced vascularization at the implantation zones, initiating the epitheliochorial placentation. To characterize the complex transcriptome changes in the endometrium in the course of initial conceptus attachment, deep sequencing of endometrial RNA samples of pregnant animals (n = 4) and corresponding cyclic controls (n = 4) was performed using Illumina RNA-Seq. The obtained sequence reads were mapped to the porcine genome, and relative expression values were calculated for the analysis of differential gene expression. Statistical analysis revealed 1933 differentially expressed genes (false discovery rate 1%), 1229 with higher and 704 with lower mRNA concentration, in the samples from pregnant animals. Expression of selected genes was validated by the use of quantitative real-time RT-PCR. The RNA-Seq data were compared to results of a microarray study of bovine endometrium on Day 18 of pregnancy and additional related data sets. Bioinformatics analysis revealed for the genes with higher mRNA concentration in pregnant samples strong overrepresentation, particularly for immune-related functional terms but also for apoptosis and cell adhesion. Overrepresented terms for the genes with lower mRNA concentration in pregnant samples were related to extracellular region, ion transport, cell adhesion, and lipid and steroid metabolic process. In conclusion, RNA-Seq analysis revealed comprehensive transcriptome differences in porcine endometrium between Day 14 of pregnancy and corresponding cyclic endometrium and highlighted new processes and pathways probably involved in regulation of noninvasive implantation in the pig.

Deep Sequencing of the Porcine Endometrial Transcriptome on Day 14 of Pregnancy

The porcine conceptus undergoes rapid differentiation and expansion of its trophoblastic membranes between Days 11 and 12 of gestation. Concomitant with trophoblast elongation, production of conceptus estrogen, the porcine embryonic pregnancy recognition signal, increases. Conceptus attachment to the uterine surface epithelium starts after Day 13, initiating epitheliochorial placentation. To analyze the transcriptome changes in the endometrium in the course of maternal recognition of pregnancy, deep sequencing of endometrial RNA samples of Day 12 pregnant animals (n = 4) and corresponding nonpregnant controls (n = 4) was performed using RNA sequencing (RNA-Seq). Between 30 000 000 and 35 000 000 sequence reads per sample were produced and mapped to the porcine genome (Sscrofa10.2). Analysis of read counts revealed 2593 differentially expressed genes (DEGs). Expression of selected genes was validated by the use of quantitative real-time RT-PCR. Bioinformatics analysis identified several functional terms specifically overrepresented for up-regulated or down-regulated genes. Comparison of the RNA-Seq data from Days 12 and 14 of pregnancy was performed at the level of all expressed genes, the level of the DEG, and the level of functional categories. This revealed specific gene expression patterns reflecting the different functions of the endometrium during these stages (i.e., recognition of pregnancy and preparation for conceptus attachment). Genes related to mitosis, immune response, epithelial cell differentiation and development, proteolysis, and prostaglandin signaling and metabolism are discussed in detail. This study identified comprehensive transcriptome changes in porcine endometrium associated with establishment of pregnancy and could be a resource for targeted studies of genes and pathways potentially involved in regulation of this process.

https://bioone.org/journals/biology-of-reproduction/volume-89/issue-6/biolreprod.113.112177/Transcriptome-Changes-in-the-Porcine-Endometrium-During-the-Preattachment-Phase1/10.1095/biolreprod.113.112177.pdf

Transcriptome Changes in the Porcine Endometrium During the Preattachment Phase

Differentially regulated microRNAs during human sebaceous lipogenesis

In mammals, an efficient exchange of molecular signals between the embryo and the maternal environment plays a crucial role for the implantation and development of early embryos as well as for recognition and maintenance of pregnancy. So far, only a few molecular signals involved in this process have been identified. To address the underlying biochemical processes in pigs at the protein level, we performed a quantitative proteome study with endometrial tissue samples from non-pregnant and pregnant (Day 14) sows. Endometrium samples (lamina epithelialis, lamina propria and tela submucosa; n = 4 per group) were taken from sites of embryonic attachment and from comparable locations in nonpregnant animals. Proteome data were generated by iTRAQ labelling and nano-LC-MS/MS measurements of tryptic endometrium peptides on a high-resolution Orbitrap XL mass spectrometer. To further address and visualize protein isoforms, LC-MS/MS experiments were complemented by 2D gel-based analyses. To enhance the accuracy of protein quantification, the 2D fluorescence difference gel electrophoresis (2D-DIGE) technique was used, including internal pooled standards for inter-gel matching and normalization. The statistical and bioinformatics analysis of 2D-DIGE and iTRAQ data revealed 14 proteins being significantly altered in abundance (fold-change values >1.5, maximum fold-change 13; P < 0.05) between the endometrium proteomes of pregnant and non-pregnant animals. Several of the affected proteins are already known to play an important role in embryo-maternal communication in other species; for example, signal transducer and activator of transcription 1 (STAT1), a protein mediating the cellular response of cells to interferons (IFN) or aldose reductase (AKR1B1), for which a key role in the synthesis of endometrial prostaglandin F is supposed. Several other proteins showing alterations in abundance between pregnant and nonpregnant endometrial tissues were not described previously and represent new and interesting targets for further functional studies addressing their role during early pregnancy.

119 quantitative proteome analysis of endometrium from pregnant and nonpregnant pigs

In pigs, conceptus attachment to the uterine surface epithelium starts around Day 14 of pregnancy preceded by a pronounced vascularization at the implantation zones, initiating the epitheliochorial placentation. To characterize the complex transcriptome changes in the endometrium in the course of initial conceptus attachment, deep sequencing of endometrial RNA samples of pregnant animals (n ¼ 4) and corresponding cyclic controls (n ¼ 4) was performed using Illumina RNA-Seq. The obtained sequence reads were mapped to the porcine genome, and relative expression values were calculated for the analysis of differential gene expression. Statistical analysis revealed 1933 differentially expressed genes (false discovery rate 1%), 1229 with higher and 704 with lower mRNA concentration, in the samples from pregnant animals. Expression of selected genes was validated by the use of quantitative realtime RT-PCR. The RNA-Seq data were compared to results of a microarray study of bovine endometrium on Day 18 of pregnancy and additional related data sets. Bioinformatics analysis revealed for the genes with higher mRNA concentration in pregnant samples strong overrepresentation, particularly for immune-related functional terms but also for apoptosis and cell adhesion. Overrepresented terms for the genes with lower mRNA concentration in pregnant samples were related to extracellular region, ion transport, cell adhesion, and lipid and steroid metabolic process. In conclusion, RNA-Seq analysis revealed comprehensive transcriptome differences in porcine endometrium between Day 14 of pregnancy and corresponding cyclic endometrium and highlighted new processes and pathways probably involved in regulation of noninvasive implantation in the pig. Illumina Genome Analyzer IIx, pig, Sus scrofa, swine, uterus

Anastazia Samborski

Papers

Deep Sequencing of the Porcine Endometrial Transcriptome on Day 14 of Pregnancy

Transcriptome Changes in the Porcine Endometrium During the Preattachment Phase

Differentially regulated microRNAs during human sebaceous lipogenesis

119 quantitative proteome analysis of endometrium from pregnant and nonpregnant pigs

Deep Sequencing of the Porcine Endometrial Transcriptome on Day 14 of Pregnancy 1