Involvement of TLR7 and TLR8 in conceptus development and establishment of pregnancy in sheep

Biosensor capability of the endometrium is mediated in part, by altered miRNA cargo from conceptus-derived extracellular vesicles

We tested the hypothesis that the biosensor capability of the endometrium is mediated in part, by the effect of different cargo contained in the extracellular vesicles secreted by the conceptus during the peri-implantation period of pregnancy. We transferred Bos taurus taurus embryos of different origin, in vivo (high developmental potential (IV)), in vitro (intermediate developmental potential (IVF)), or cloned (low developmental potential (NT)), into Bos taurus indicus recipients. Extracellular vesicles (EVs) recovered from Day 16 conceptus-conditioned medium were characterized and their microRNA (miRNA) cargo sequenced alongside RNA sequencing of their respective endometria. There were substantial differences in the endometrial response to in vivo versus in vitro and in vivo versus cloned conceptuses (1153 and 334DEGs respectively) with limited differences between in vitro Vs cloned conceptuses (36 DEGs). The miRNA cargo contained in conceptus-derived EVs was similar between all three groups (426 miRNA in common). Only 8 miRNAs were different between in vivo and cloned conceptuses, while only 6 miRNAs were different between in vivo and in vitro-derived conceptuses. Treatment of endometrial epithelial cells with mimic or inhibitors for miR-128 and miR-1298 changed the proteomic content of target cells (96 and 85, respectively) of which mRNAs are altered in the endometrium in vivo (PLXDC2, COPG1, HSPA12A, MCM5, TBL1XR1, and TTF). In conclusion, we have determined that the biosensor capability of the endometrium is mediated in part, by its response to different EVs miRNA cargo produced by the conceptus during the peri-implantation period of pregnancy.

Actions of FGF2, LIF, and IGF1 on bovine embryo survival and conceptus elongation following slow-rate freezing

Culture environment during in vitro embryo production can affect embryo phenotype and pregnancy outcomes, making culture modifications a logical approach for improving embryo competence. Previously, the addition of the growth factors FGF2, LIF, and IGF1, termed FLI, to the culture medium improved bovine embryo development, and re-expansion following cryopreservation. The objective of this study was to investigate the survival of cryopreserved FLI treated embryos at day 15 of pregnancy and evaluate conceptus transcriptomes. Embryos were produced using in vitro fertilization of abattoir-derived oocytes, cultured to the blastocyst stage in the presence or absence of FLI (+/- FLI), and cryopreserved by slow-rate freezing. Thawed embryos were transferred into non-lactating recipient beef cows and eight days later conceptuses were recovered and analyzed. For a subset of conceptuses whole transcriptome analysis was performed by using the NovaSeq 6000. There was no detectable difference in conceptus recovery or average conceptus length between the two groups. There were 32 differentially expressed transcripts, 23 up-regulated and nine down-regulated in the +FLI group compared to -FLI. Genes were involved in interferon signaling, prostaglandin synthesis, and placental development. This study reveals that embryos cultured with or without FLI and cryopreserved by slow-rate freezing have similar developmental competence up to day 15 of development. Nevertheless, differences in gene expression exhibit an effect of FLI on conceptus signaling during elongation.

Cell-Specific Expression Pattern of Toll-Like Receptors and Their Roles in Animal Reproduction

Toll-like receptors (TLRs), a part of the innate immune system, have critical roles in protection against infections and involve in basic pathology and physiology. Secreted molecules from the body or pathogens could be a ligand for induction of the TLR system. There are many immune and non-immune types of cells that express at a least single TLR on their surface or cytoplasm. Those cells may be a player in a defense system or in the physiological regulation mechanisms. Reproductive tract and organs contain different types of cells that have essential functions such as hormone production, providing an environment for embryo/fetus, germ cell production, etc. Although lower parts of reproductive organs are in a relationship with outsider contaminants (bacteria, viruses, etc.), upper parts should be sterile to provide a healthy pregnancy and germ cell production. In those areas, TLRs bear controller or regulator roles. In this chapter, we will provide current information about physiological functions of TLR in the cells of the reproductive organs and tract, and especially about their roles in follicle selection, maturation, follicular atresia, ovulation, corpus luteum (CL) formation and regression, establishment and maintenance of pregnancy, sperm production, maturation, capacitation as well as the relationship between TLR polymorphism and reproduction in domestic animals. We will also discuss pathogen-associated molecular patterns (PAMPs)-induced TLRs that involve in reproductive inflammation/pathology.

Toll-like receptor signaling is changed in ovine lymph node during early pregnancy

Toll-like receptors (TLRs) participate in regulation of adaptive immune responses, and lymph nodes play key roles in the initiation of immune responses. There is a tolerance to the allogenic fetus during pregnancy, but it is unclear that expression of TLR signaling is in ovine lymph node during early pregnancy. In this study, lymph nodes were sampled from day 16 of nonpregnant ewes and days 13, 16, and 25 of pregnant ewes, and the expressions of TLR family (TLR2, TLR3, TLR4, TLR5 and TLR9), adaptor proteins, including myeloid differentiation primary-response protein 88 (MyD88), tumor necrosis factor receptor associated factor 6 (TRAF6), and interleukin-1-receptor-associated kinase 1 (IRAK1), were analyzed through real-time quantitative polymerase chain reaction, Western blot, and immunohistochemistry analysis. The results showed that mRNA and protein levels of TLR2, TLR3, TLR4, TRAF6, and MyD88 were upregulated in the maternal lymph node, but TLR5, TLR9, and IRAK1 were downregulated during early pregnancy. In addition, MyD88 protein was located in the subcapsular sinus and lymph sinuses. Therefore, it is suggested that early pregnancy induces changes in TLR signaling in maternal lymph node, which may be involved in regulation of maternal immune responses in sheep.

Early pregnancy affects expression of Toll-like receptor signaling members in ovine spleen

Toll-like receptors (TLRs) are involved to the maternal immune tolerance. The spleen is essential for adaptive immune reactions. However, it is unclear that early pregnancy regulates TLR-mediated signalings in the maternal spleen. The purpose of this study was to investigate the effects of early pregnancy on expression of TLR signaling members in the ovine spleen. Ovine spleens were collected at day 16 of the estrous cycle, and at days 13, 16 and 25 of pregnancy (n = 6 for each group). Real-time quantitative PCR, western blot and immunohistochemistry analysis were used to detect TLR signaling members, including TLR2, TLR3, TLR4, TLR5, TLR7, TLR9, myeloid differentiation primary-response protein 88 (MyD88), tumor necrosis factor receptor associated factor 6 (TRAF6) and interleukin-1-receptor-associated kinase 1 (IRAK1). The results showed that expression levels of TLR2, TLR4 and IRAK1 were downregulated, but expression levels of TLR3, TLR5, TLR7, TLR9, TRAF6 and MyD88 were increased during early pregnancy. In addition, MyD88 protein was located in the capsule, trabeculae and splenic cords of the maternal spleen. This paper reports for the first time that early pregnancy has effects on TLR signaling pathways in the ovine spleen, which is beneficial for understanding the maternal immune tolerance during early pregnancy.

Differential expression of endometrial toll-like receptors (TLRs) and antimicrobial peptides (AMPs) in the buffalo (Bubalus bubalis) with endometritis

Toll like receptors (TLRs) and β-defensins expressed in the endometrium are part of the innate uterine defense mechanism (UDM). In the present study, transcriptional profile of TLRs (1-3, 6-8, 10, and) and β-defensins such as lingual antimicrobial peptide (LAP), tracheal antimicrobial peptide (TAP) and bovine neutrophil beta-defensin 4 (BNBD4) were studied. Bubaline genitalia were collected from abattoir and the endometrium was categorized into one of the following seven groups (n = 7/group) based on cyclicity and endometritis: follicular non-endometritis (FNE), luteal non-endometritis (LNE), follicular cytological endometritis (FCE), luteal cytological endometritis (LCE), follicular purulent endometritis (FPE), luteal purulent endometritis (LPE) and acyclic non-endometritis (ANE). Cytological endometritis (CE) was diagnosed by uterine cytology while purulent endometritis (PE) was diagnosed by the presence of purulent or mucopurulent exudate in the uterine lumen. Real time PCR was performed and the relative fold change was analysed. TLR1 and BNBD4 transcripts were not found in the buffalo endometrium. Of all the innate immune genes studied, upregulation of TLR and β-defensins was mostly contributed by the inflammatory status of endometrium. Further, there was a prominent upregulation of TAP in buffaloes with endometritis. However, no association could be found between the inflammatory status of the endometrium and phase of estrous cycle with respect to the expression of TLRs and β-defensins.

Bioinformatics Analysis of Differentially Expressed Genes, Methylated Genes, and miRNAs in Unexplained Recurrent Spontaneous Abortion

Approximately half of the unexplained recurrent spontaneous abortions remain unexplained (URSAs). We aimed to provide novel insights into the biological characteristics and related pathways of differentially expressed genes (DE-genes), DE-methylated genes, and DE-miRNAs in URSA, and construct a molecular miRNAs-mRNAs network. Four data sets (GSE22490, GSE121950, GSE73025, and GSE43256) were gained from GEO data sets. We identified the DE-genes, DE-methylated genes, and DE-miRNAs using the LIMMA package in R software. Function and enrichment analyses were conducted using DAVID. A protein-protein network was performed by STRING. We predicted the target genes of DE-miRNA using DIANA-microT-CDS. Then, we constructed miRNAs-mRNAs network. There were 137 genes that overlapped in two expression profile data sets (GSE121950 and GSE22490). We found 10 overlapping DE-methylated genes and DE-genes with opposite expression alteration trends. All those 10 genes were hypermethylated lowly expressed genes. Pathway analysis illustrated that DE-genes were enriched in osteoclast differentiation, leishmaniasis, NF-kappa B signaling pathway, Toll-like receptor signaling pathway, and tuberculosis. Based on protein-protein interaction analysis, TLR8, TLR2, CD86, TLR4, IL10, CD163, FCGR1A, CXCL8, FCGR3A, HCK, PLEK, and MNDA were identified as hub genes for DE-genes. We screened out 47 DE-miRNAs and 42 overlapping DE-genes between predicted target genes of DE-miRNAs and the 137 DE-genes. We then constructed miRNAs-mRNAs network. This study identified several genes and miRNAs involved in the development and progression of URSA, including FCGR1A, FCGR3A, CXCL8, HCK, PLEK, IL10, hsa-miR-498, and hsa-miR-4530. Although further in vivo and in vitro validations are required, our results may provide a theoretical basis for future studies.

PATL2 is a key actor of oocyte maturation whose invalidation causes infertility in women and mice

The genetic causes of oocyte meiotic deficiency (OMD), a form of primary infertility characterised by the production of immature oocytes, remain largely unexplored. Using whole exome sequencing, we found that 26% of a cohort of 23 subjects with OMD harboured the same homozygous nonsense pathogenic mutation in PATL2, a gene encoding a putative RNA‐binding protein. Using Patl2 knockout mice, we confirmed that PATL2 deficiency disturbs oocyte maturation, since oocytes and zygotes exhibit morphological and developmental defects, respectively. PATL2's amphibian orthologue is involved in the regulation of oocyte mRNA as a partner of CPEB. However, Patl2's expression profile throughout oocyte development in mice, alongside colocalisation experiments with Cpeb1, Msy2 and Ddx6 (three oocyte RNA regulators) suggest an original role for Patl2 in mammals. Accordingly, transcriptomic analysis of oocytes from WT and Patl2^−/− animals demonstrated that in the absence of Patl2, expression levels of a select number of highly relevant genes involved in oocyte maturation and early embryonic development are deregulated. In conclusion, PATL2 is a novel actor of mammalian oocyte maturation whose invalidation causes OMD in humans.

Identification of mRNAs related to endometrium function regulated by lncRNA CD36-005 in rat endometrial stromal cells

BACKGROUND

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder in women of reproductive age and is commonly complicated by adverse endometrial outcomes. Long non-coding RNAs (lncRNAs) are a class of non-protein-coding transcripts that are more than 200 nucleotides in length. Accumulating evidence indicates that lncRNAs are involved in the development of various human diseases. Among these lncRNAs, lncRNA CD36-005 (CD36-005) is indicated to be associated with the pathogenesis of PCOS. However, the mechanisms of action of CD36-005 have not yet been elucidated.

METHODS

This study determined the CD36-005 expression level in the uteri of PCOS rat model and its effect on the proliferation activity of rat primary endometrial stromal cells. RNA sequencing (RNA-seq) and bioinformatics analysis were performed to detect the mRNA expression profiles and the biological pathways in which these differentially expressed mRNAs involved, after CD36-005 overexpression in the primary endometrial stromal cells. The differential expression of Hmgn5, Nr5a2, Dll4, Entpd1, Fam50a, and Brms1 were further validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR).

RESULTS

CD36-005 is highly expressed in the uteri of PCOS rat model and promotes the proliferation of rat primary endometrial stromal cells. A total of fifty-five mRNAs differentially expressed were identified in CD36-005 overexpressed stromal cells. Further analyses identified that these differentially expressed mRNAs participate in many biological processes and are associated with various human diseases. The results of qRT-PCR validation were consistent with the RNA-seq data.

CONCLUSIONS

These data provide a list of potential target mRNA genes of CD36-005 in endometrial stromal cells and laid a foundation for further studies on the molecular function and mechanism of CD36-005 in the endometrium.

Delivery of Morpholino Antisense Oligonucleotides to a Developing Ovine Conceptus via Luminal Injection into a Ligated Uterine Horn

In vivo delivery of morpholino antisense oligonucleotides (MAO) directly into the uterine lumen of a peri-implantation period pregnant sheep is an effective technique for evaluation of gene products for conceptus development. The highly phagocytic conceptus is undergoing rapid morphological change, thereby the available MAO are readily consumed and delivered to developing cells. Here, we describe the method for preparation and surgical delivery of MAO-Endo-Porter complex to developing ovine conceptus on day 8 postmating. Also outlined are methods for posttreatment sample recovery on day 16 postmating.

Functional roles of ornithine decarboxylase and arginine decarboxylase during the peri-implantation period of pregnancy in sheep

Background

Polyamines stimulate DNA transcription and mRNA translation for protein synthesis in trophectoderm cells, as well as proliferation and migration of cells; therefore, they are essential for development and survival of conceptuses (embryo/fetus and placenta). The ovine conceptus produces polyamines via classical and non-classical pathways. In the classical pathway, arginine (Arg) is transformed into ornithine, which is then decarboxylated by ornithine decarboxylase (ODC1) to produce putrescine which is the substrate for the production of spermidine and spermine. In the non-classical pathway, Arg is converted to agmatine (Agm) by arginine decarboxylase (ADC), and Agm is converted to putrescine by agmatinase (AGMAT).

Methods

Morpholino antisense oligonucleotides (MAOs) were designed and synthesized to inhibit translational initiation of the mRNAs for ODC1 and ADC, in ovine conceptuses.

Results

The morphologies of MAO control, MAO-ODC1, and MAO-ADC conceptuses were normal. Double knockdown of ODC1 and ADC (MAO-ODC1:ADC) resulted in two phenotypes of conceptuses; 33% of conceptuses appeared to be morphologically and functionally normal (phenotype a) and 67% of the conceptuses presented an abnormal morphology and functionality (phenotype b). Furthermore, MAO-ODC1:ADC (a) conceptuses had greater tissue concentrations of Agm, putrescine, and spermidine than MAO control conceptuses, while MAO-ODC1:ADC (b) conceptuses only had greater tissue concentrations of Agm . Uterine flushes from ewes with MAO-ODC1:ADC (a) had greater amounts of arginine, aspartate, tyrosine, citrulline, lysine, phenylalanine, isoleucine, leucine, and glutamine, while uterine flushes of ewes with MAO-ODC1:ADC (b) conceptuses had lower amount of putrescine, spermidine, spermine, alanine, aspartate, glutamine, tyrosine, phenylalanine, isoleucine, leucine, and lysine.

Conclusions

The double-knockdown of translation of ODC1 and ADC mRNAs was most detrimental to conceptus development and their production of interferon tau (IFNT). Agm, polyamines, amino acids, and adequate secretion of IFNT are critical for establishment and maintenance of pregnancy during the peri-implantation period of gestation in sheep.

Electronic supplementary material

The online version of this article (10.1186/s40104-017-0225-x) contains supplementary material, which is available to authorized users.

Early pregnancy-related changes in toll-like receptors expression in ovine trophoblasts and peripheral blood leukocytes

In the present study, we aimed to 1) demonstrate the presence of all 10 toll-like receptors (TLRs) in ovine trophoblasts, and 2) investigate the expression profiles of TLR1-10 mRNAs in peripheral blood leukocytes (PBLs) in ewes during early pregnancy. For those purposes, ovine trophoblasts (n = 6) were collected from pregnant ewes on day 13. PBLs were collected from non-pregnant (n = 6) and pregnant ewes (n = 17) on days of mating (d) 0 and 18. TLR mRNAs in ovine trophoblasts were visualized by free-floating in situ hybridization (ISH). To assess the expression profiles of TLR1-10 in PBLs, total RNA was isolated and transcribed to cDNA. TLR1-10 mRNA levels were determined by real-time PCR in triplicate. The Relative Expression Software Tool (REST 2009) was used for statistical analysis. We detected mRNAs for TLR2, TLR4, TLR5, TLR6, TLR7, TLR8, and TLR10 but not for TLR1, TLR3, and TLR9 in trophoblasts. TLR2, TLR5, TLR6, TLR7, TLR8, and TLR10 mRNAs were expressed by all trophoblasts, whereas TLR4 mRNA and protein in trophoblasts were more limited. In PBLs, TLR expression did not differ between day 0 and day 18 in non-pregnant ewes; however, ewes in early pregnancy exhibited significantly upregulated expression of TLR2 (2.3-fold), TLR4 (3.1-fold), TLR6 (1.7-fold), and TLR8 (2.2-fold) on day 18 compared with day 0. In contrast, TLR10 was downregulated (2-fold) on day 18 by pregnancy. Similar results were also obtained for TLR2, TLR4, TLR6, TLR8 and TLR10 from the comparison between day 18 non -pregnant and day 18 pregnant groups. According to these results, the presence of TLRs in early ovine trophoblasts suggests that these cells play an immunological role at the maternal-fetal interface. The results also suggest that tight regulation of some components of TLRs in PBLs due to embryo- and/or pregnancy-related factors is necessary for successful establishment of early pregnancy in ewes.

Innate immunity and the sensing of infection, damage and danger in the female genital tract

Tissue homeostasis in the female genital tract is challenged by infection, damage, and even physiological events during reproductive cycles. We propose that the evolutionarily ancient system of innate immunity is sufficient to sense and respond to danger in the non-pregnant female genital tract. Innate immunity produces a rapidly inducible, non-specific response when cells sense danger. Here we provide a primer on innate immunity and discuss what is known about how danger signals are sensed in the endometrium and ovary, the impact of inflammatory responses on reproduction, and how endocrinology and innate immunity are integrated. Endometrial epithelial and stromal cells, and ovarian granulosa cells express pattern recognition receptors, similar to cells of the innate immune system. These pattern recognition receptors, such as the Toll-like receptors, bind pathogen-associated or damage-associated molecular patterns. Activation of pattern recognition receptors leads to inflammation, recruitment of immune cells from the peripheral circulation, and phagocytosis. Although the inflammatory response helps maintain or restore endometrial health, there may also be negative consequences for fertility, including perturbation of oocyte competence. The intensity of the inflammatory response reflects the balance between the level of danger and the systems that regulate innate immunity, including the endocrine environment. Understanding innate immunity is important because disease and inappropriate inflammatory responses in the endometrium or ovary cause infertility.

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.