Identification of a novel role for endothelins within the oviduct

Comprehensive analysis of immune-related genes associated with the microenvironment of patients with unexplained infertility

Background

Disturbances in immunological responses and modulation lead to implantation and pregnancy failure and might be involved in the pathogenesis of infertility. This project aimed to screen and identify immune-related genes as potential biomarkers for treatment.

Methods

Gene expression profiles were obtained from Gene Expression Omnibus (GEO) databases. Differentially expressed genes (DEGs) were screened using GEO 2R to explore potential biomarkers. Protein-protein interaction (PPI) network analysis and functional enrichment analysis were applied to explore possible mechanisms. The deconvolution algorithm [referred to as Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT)] was employed to assess tissue-infiltrating immune cells. Western blot analysis and immunohistochemistry (IHC) were conducted for determination of protein levels.

Results

In this research, we identified 24 candidate immune-related DEGs via combined DEGs and functional analysis. We also found that the ratio of M0 macrophages and resting mast cells was higher in infertile group (P<0.05), whereas the amounts of activated natural killer (NK) cells was significantly lower compared with the control group (P<0.05). Furthermore, we evaluated the relationship between immune cells and candidate genes and found that 17 genes were related to M0 macrophages, resting mast cells, or activated NK cells. The genes CD40, PRF1, and EDN3 were chosen based on validation from independent datasets. Finally, our clinical samples confirmed the expression of the 3 genes.

Conclusions

The study recognized 3 genes that are signatures and could be potential biomarkers for unexplained infertility. These genes might guide the immunotherapy of these patients and become new treatment targets.

Lateral oviduct-secreted proteins in the brown planthopper

Oviducts are the "traffic hubs" of the female reproductive system, serving as the crucial conduits for egg transportation. By performing LC-MS/MS proteomic detection together with transcriptomic analysis, 80 lateral oviduct-secreted proteins were identified, and 5 genes (NlOdsp, NlOdsp1, NlOdsp2, NlOdsp3 and NlOdsp4) specifically expressed in the oviducts of the brown planthopper Nilaparvata lugens, the most destructive rice pest, were authenticated. qRT-PCR analysis revealed that these genes and proteins were mainly/specifically expressed in the female reproductive system in adulthood. RNA interference (RNAi) against the 5 NlOdsp genes significantly affected the survival rates (3.4% - 68.7% of the control) and fecundities of female adults (3.9% - 57.6% of the control) at 8 d post injection (p.i.). In addition, the lack of NlOdsp1 caused decreases in the gel-like brown secretions inside the lateral oviducts, while increased secretions were found in the dsNlOdsp2-treated groups. In addition, NlOdsp3 is a pleiotropic gene involved in both oocyte development and egg movement through the lateral oviducts, similar to the role of NlOdsp in egg transportation. The results deepen our understanding of oviduct-secreted proteins in female insects and provide novel target genes for RNAi-based insect pest control. SIGNIFICANCE: Oviduct plays a vital role in animal reproductive processes and it serves as the crucial conduit for egg transportation. Though oviduct secretes have been well documented in high animals, the proteomic information of insect oviduct secretes remains poorly understood. The present study revealed 80 oviduct secreted proteins, including 19 unknown proteins, from the rice planthopper, the most destructive rice pest which lay eggs in plant tissues. Five of the 19 proteins were further functionally characterized. The results not only deepen our understanding of the oviduct secreted proteins in insect reproductive biology, but also provide basis for interaction between insects and host plants, and provide novel target genes for RNAi-based insect pest control.

A lateral oviduct secreted protein plays a vital role for egg movement through the female reproductive tract in the brown planthopper

The oviduct serves as a delivery tube for mature eggs ovulated from ovaries to egg-laying sites. Oviduct secreted components play important roles in ovulation and fertilization in mammals, however, no oviduct secreted protein has been characterized in an insect to date. Here, we identified a gene highly expressed in the lateral oviduct of the adult females in the brown planthopper (BPH), Nilaparvata lugens, the most destructive rice insect pest. Western blotting and immunofluorescence analyses revealed that the gene encodes a protein that is specifically expressed in the lateral oviduct as a component of the gel-like material secreted by the oviduct epithelial cells into the lumen of the swollen part of the lateral oviducts. The protein was tentatively named N. lugens oviduct secreted protein (Nlodsp). RNA interference (RNAi) against NlOdsp transcripts caused a failure of the lateral oviducts to deliver oocytes to the common oviduct that was, by consequence, plugged by 1-2 oocytes. Moreover, although oocytes in the Nlodsp-deficient ovariole were not released to the oviduct, they continued to develop, finally resulting in the presence of several matured oocytes in an ovariole. These defects evidently declined female fecundity. Together, our results demonstrate that NlOdsp plays an essential role in egg transport through the oviduct during ovulation. This work deepens our understanding of insect reproductive system and provides a potential target gene for RNAi-based insect pest control.

Essential Role of Complement in Pregnancy: From Implantation to Parturition and Beyond

The complement cascade was identified over 100 years ago, yet investigation of its role in pregnancy remains an area of intense research. Complement inhibitors at the maternal-fetal interface prevent inappropriate complement activation to protect the fetus. However, this versatile proteolytic cascade also favorably influences numerous stages of pregnancy, including implantation, fetal development, and labor. Inappropriate complement activation in pregnancy can have adverse lifelong sequelae for both mother and child. This review summarizes the current understanding of complement activation during all stages of pregnancy. In addition, consequences of complement dysregulation during adverse pregnancy outcomes from miscarriage, preeclampsia, and pre-term birth are examined. Finally, future research directions into complement activation during pregnancy are considered.

Genomic Analysis Reveals Pleiotropic Alleles at EDN3 and BMP7 Involved in Chicken Comb Color and Egg Production

Artificial selection is often associated with numerous changes in seemingly unrelated phenotypic traits. The genetic mechanisms of correlated phenotypes probably involve pleiotropy or linkage of genes related to such phenotypes. Dongxiang blue-shelled chicken, an indigenous chicken breed of China, has segregated significantly for the dermal hyperpigmentation phenotype. Two lines of the chicken have been divergently selected with respect to comb color for over 20 generations. The red comb line chicken produces significantly higher number of eggs than the dark comb line chicken. The objective of this study was to explore potential mechanisms involved in the relationship between comb color and egg production among chickens. Based on the genome-wide association study results, we identified a genomic region on chromosome 20 involving EDN3 and BMP7, which is associated with hyperpigmentation of chicken comb. Further analyses by selection signatures in the two divergent lines revealed that several candidate genes, including EDN3, BMP7, BPIFB3, and PCK1, closely located on chromosome 20 are involved in the development of neural crest cell and reproductive system. The two genes EDN3 and BMP7 have known roles in regulating both ovarian function and melanogenesis, indicating the pleiotropic effect on hyperpigmentation and egg production in blue-shelled chickens. Association analysis for egg production confirmed the pleiotropic effect of selected loci identified by selection signatures. The study provides insights into phenotypic evolution due to genetic variation across the genome. The information might be useful in the current breeding efforts to develop improved breeds for egg production.

Ontology groups representing angiogenesis and blood vessels development are highly up-regulated during porcine oviductal epithelial cells long-term real-time proliferation – a primary cell culture approach

The morphological and biochemical modification of oviductal epithelial cells (OECs) belongs to the group of compound processes responsible for proper oocyte transport and successful fertilization. The cellular interactions between cumulus-oocyte complexes (COCs) and oviductal epithelial cells (OECs) are crucial for this unique mechanism. In the present study we have analyzed angiogenesis and blood vessel development processes at transcript levels. By employing microarrays, four ontological groups associated with these mechanisms have been described. Differentially expressed genes belonging to the “angiogenesis”, “blood circulation”, “blood vessel development” and “blood vessel morphogenesis” GO BP terms were investigated as a potential markers for the creation of new blood vessels in cells under in vitro primary culture conditions.

Natural and environmental oestrogens induce TGFB1 synthesis in oviduct cells

Autocrine/paracrine factors generated in response to 17β-oestradiol (E2), within the oviduct, facilitate early embryo development for implantation. Since transforming growth factor beta 1 (TGFB1) plays a key role in embryo implantation, regulation of its synthesis by E2 may be of biological/pathophysiological relevance. Here, we investigated whether oviduct cells synthesize TGFB1 and whether E2 and environmental oestrogens (EOEs; xenoestrogens and phytoestrogens) modulate its synthesis. Under basal conditions, bovine oviduct cells (OCs; oviduct epithelial cells and oviduct fibroblasts; 1:1 ratio) synthesized TGFB1. E2 concentration-dependent induced TGFB1 levels in OCs and these effects were mimicked by some, but not all EOEs (genistein, biochanin A and 4-hydroxy-2',4',6'-trichlorobiphenyl, 4-hydroxy-2',4',6'-dichlorobiphenyl); moreover, EOEs enhanced (P < 0.05) the stimulatory effects of E2 on TGFB1 synthesis. The OCs expressed oestrogen receptors alpha and beta and aryl hydrocarbon; moreover, co-treatment with ER antagonist ICI182780 blocked the stimulatory effects of E2 and EOEs on TGFB1 synthesis. Treatment with non-permeable E2-BSA failed to induce TGFB1, thereby ruling out the involvement of membrane ERs. Cycloheximide (protein synthesis inhibitor) blocked E2-induced TGFB1 synthesis providing evidence for de novo synthesis. The stimulatory effects of E2 and EOEs, were inhibited (P < 0.05) by MAPK inhibitor (PD98059), whereas intracellular-Ca²⁺ chelator (BAPTA-AM) and adenylyl cyclase inhibitor (SQ22536) abrogated the effects of E2, but not EOEs, suggesting that post-ER effects of E2 and EOEs involve different pathways. Our results provide the first evidence that in OCs, E2 and EOEs stimulate TGFB1 synthesis via an ER-dependent pathway. Exposure of the oviduct to EOEs may result in continuous/sustained induction of TGFB1 levels in a non-cyclic fashion and may induce deleterious effects on reproduction.

Effect of lipopolysaccharide on the expression of inflammatory mRNAs and microRNAs in the mouse oviduct

Infection with Gram-negative bacteria is a major cause of aberrant inflammation in the oviduct; consequences can include tubal-based infertility and/or ectopic pregnancy. Understanding the inflammatory response is necessary for the development of novel treatment options that counter inflammation-induced infertility. The aim of the present study was to determine the effect of intraperitoneal (i.p.) administration of Escherichia coli-derived lipopolysaccharide (LPS) on the acute expression of inflammatory mRNAs and microRNAs (miRNAs) in the oviduct. On the day of oestrus, 6- to 8-week-old CD1 mice were injected i.p. with 0, 2 or 10µg LPS in 100μL phosphate-buffered saline. Mice were killed 24h later and the oviducts collected for gene expression analyses. The effect of treatment on the expression of mRNAs and miRNAs was evaluated by one-way analysis of variance (ANOVA), with treatment means of differentially expressed (P<0.05) transcripts separated using Scheffé's test. LPS treatment affected 49 of 179 targeted inflammatory mRNAs and 51 of 578 miRNAs (P<0.05). The identity of differentially expressed miRNAs predicted as regulators of chemokine and interleukin ligand mRNAs was then extracted using the microRNA.org database. The results of the present study indicate that systemic treatment with LPS induces a robust inflammatory response in the oviducts of mice, and identify key mRNAs and putative miRNAs modulating this effect.

Roles of EDNs in regulating oviductal NO synthesis and smooth muscle motility in cows

Endothelins (EDNs) participate in various physiological events including smooth muscle contraction, nitric oxide (NO) synthesis, and embryonic development. In this study, we investigated the regional roles of EDNs produced by bovine oviductal epithelial cells in NO synthesis and smooth muscle motility. Quantification of mRNA expressions indicated that expression of EDN receptor B (EDNRB) in the ampullary region was higher after ovulation than before ovulation, whereas expression of EDNRA in the isthmic region was higher after ovulation than before ovulation. Immunohistochemistry revealed that the EDN receptors (EDNRA and EDNRB) were expressed in the epithelium, whereas smooth muscle showed positive staining only for EDNRA. The expressionsPlease suggest whether 'NOS2' can be treated as the updated symbol for 'iNOS' as per gene nomenclature. of inducible NO synthase (iNOS) protein and its mRNA (NOS2) in cultured epithelial cells isolated from the ampulla were stimulated by EDN1, but not by EDN2 or EDN3, after 1h of incubation. In isthmic epithelial cells, none of the EDNs affected the expression of NOS2 Isometric contraction tests indicated that spontaneous waves were strong in the isthmic region but weak in the ampullary region. EDN1 modulated smooth muscle motility in both the regions. The overall findings suggest that EDN1 plays region-specific roles in smooth muscle motility and epithelial NO synthesis, providing an optimal oviductal microenvironment for transport of gametes, fertilization, and development/transport of early embryo.

Regulation of bovine oviductal NO synthesis by follicular steroids and prostaglandins

Nitric oxide (NO) is a regulator of sperm motility, oocyte/embryo survival, and waves of contraction/relaxation in mammalian oviducts. As follicles control oviductal functions by two routes at least, (1) a systemic way via blood vessels before ovulation, (2) a direct way by entering of follicular fluid through fimbria at ovulation, we hypothesized that NO synthesis in the bovine oviduct is regulated by follicular steroids and prostaglandins (PGs). Quantification of mRNA expressions in the ampullary tissues showed that inducible NO synthase (NOS2) mRNA expression was highest on the day of ovulation (day 0). By contrast, NOS2 mRNA expression in the isthmus was highest on days 5-6 and lowest on days 19-21. Endothelial NOS (NOS3) mRNA expressions in either the ampulla or the isthmus did not change during the estrous cycle. PGE2 and PGF2α increased NOS2 mRNA expressions in cultured ampullary oviductal epithelial cells after 1-h incubation. These increases were suppressed by an antagonist of E-prostanoid receptor type 2, one of the PGE2 receptor. Estradiol-17β decreased the expression of NOS2 mRNA expression in cultured isthmic epithelial cells 24h after treatment. This effect was suppressed by an antagonist of estrogen receptorα(ESR1). Expression of ESR1 was highest on days 19-21 in the isthmic tissues. The overall findings indicate region-specific difference of NO synthesis in the oviduct. PGs flowed from ruptured follicle may up-regulate NO synthesis in the oviductal epithelium, whereas circulating E2 seems to inhibit NO synthesis via ESR1 in the isthmus at the follicular stage.

Estrogen Receptor Alpha (ESR1)-Dependent Regulation of the Mouse Oviductal Transcriptome

Estrogen receptor-α (ESR1) is an important transcriptional regulator in the mammalian oviduct, however ESR1-dependent regulation of the transcriptome of this organ is not well defined, especially at the genomic level. The objective of this study was therefore to investigate estradiol- and ESR1-dependent regulation of the transcriptome of the oviduct using transgenic mice, both with (ESR1KO) and without (wild-type, WT) a global deletion of ESR1. Oviducts were collected from ESR1KO and WT littermates at 23 days of age, or ESR1KO and WT mice were treated with 5 IU PMSG to stimulate follicular development and the production of ovarian estradiol, and the oviducts collected 48 h later. RNA extracted from whole oviducts was hybridized to Affymetrix Genechip Mouse Genome 430–2.0 arrays (n = 3 arrays per genotype and treatment) or reverse transcribed to cDNA for analysis of the expression of selected mRNAs by real-time PCR. Following microarray analysis, a statistical two-way ANOVA and pairwise comparison (LSD test) revealed 2428 differentially expressed transcripts (DEG’s, P < 0.01). Genotype affected the expression of 2215 genes, treatment (PMSG) affected the expression of 465 genes, and genotype x treatment affected the expression of 438 genes. With the goal of determining estradiol/ESR1-regulated function, gene ontology (GO) and bioinformatic pathway analyses were performed on DEG’s in the oviducts of PMSG-treated ESR1KO versus PMSG-treated WT mice. Significantly enriched GO molecular function categories included binding and catalytic activity. Significantly enriched GO cellular component categories indicated the extracellular region. Significantly enriched GO biological process categories involved a single organism, modulation of a measurable attribute and developmental processes. Bioinformatic analysis revealed ESR1-regulation of the immune response within the oviduct as the primary canonical pathway. In summary, a transcriptomal profile of estradiol- and ESR1-regulated gene expression and related bioinformatic analysis is presented to increase our understanding of how estradiol/ESR1 affects function of the oviduct, and to identify genes that may be proven as important regulators of fertility in the future.

Gestational form of Selenium in Free-Choice Mineral Mixes Affects Transcriptome Profiles of the Neonatal Calf Testis, Including those of Steroidogenic and Spermatogenic Pathways

In areas where soils are deficient in Selenium (Se), dietary supplementation of this trace mineral directly to cattle is recommended. Because Se status affects testosterone synthesis and frequency of sperm abnormalities, and the form of Se supplemented to cows affects tissue-specific gene expression, the objective of this study was to determine whether the form of Se consumed by cows during gestation would affect the expression of mRNAs that regulate steroidogenesis and/or spermatogenesis in the neonatal calf testis. Twenty-four predominantly Angus cows were assigned randomly to have individual, ad libitum, access of a mineral mix containing 35 ppm of Se in free-choice vitamin-mineral mixes as either inorganic (ISe), organic (OSe), or a 50/50 mix of ISe and OSe (MIX), starting 4 months prior to breeding and continuing throughout gestation. Thirteen male calves were born over a 3-month period (ISe, n = 5; OSe, n = 4; MIX, n = 4), castrated within 2 days of birth, and extracted testis RNA subjected to transcriptomal analysis by microarray (Affymetrix Bovine 1.0 ST arrays) and targeted gene expression analysis by real-time reverse-transcription PCR (RT-PCR) of mRNAs encoding proteins known to affect steroidogenesis and/or spermatogenesis. The form of dam Se affected (P < 0.05) the expression of 853 annotated genes, including 17 mRNAs putatively regulating steroidogenesis and/or spermatogenesis. Targeted RT-PCR analysis indicated that the expression of mRNA encoding proteins CYP2S1 (cytochrome P450, family 2, subfamily S, polypeptide 1), HSD17B7 (hydroxysteroid (17β) dehydrogenase 7), SULT1E1 (sulfotransferase family 1E, estrogen preferring, member 1), LDHA (lactate dehydrogenase A), CDK5R1 (cyclin-dependent kinase 5, regulatory subunit 1), and LEP (leptin) was affected (P < 0.05) by form of Se consumed by dams of developing bull calves, while AKR1C4 (aldo-keto reductase family 1, member C4) and CCND2 (cyclin D2) tended (P < 0.09) to be affected. Our results indicate that form of Se fed to dams during gestation affected the transcriptome of the neonatal calf testis. If these profiles are maintained throughout maturation, then the form of Se fed to dams may impact bull fertility and the development of Se form-dependent mineral mixes that target gestational development of the testis are warranted.

Endothelin as a local regulating factor in the bovine oviduct

Endothelin (EDN) is a possible regulating factor of oviductal motility, which is important for the transport of gametes and embryo. To clarify the factors that control the secretion of EDN in the bovine oviduct, the expression of EDNs, EDN-converting enzymes (ECEs) and EDN receptors (EDNRs) were investigated. All isoforms of EDN (EDN1–3), ECE (ECE1 and ECE2) and EDNR (EDNRA and EDNRB) were immunolocalised in the epithelial cells of the ampulla and the isthmus. EDNRs were also immunolocalised in smooth-muscle cells. The mRNA expression of EDN2 and ECE2 was higher in cultured ampullary oviductal epithelial cells than in isthmic cells. The expression of EDN1, EDN2 and ECE2 in the ampullary tissue was highest on the day of ovulation. Oestradiol-17β increased EDN2 and ECE1 expression, while progesterone increased only ECE1 expression in cultured ampullary epithelial cells. These results indicate that EDNs are produced by epithelial cells and their target site is smooth-muscle and epithelial cells, and suggest that ovarian steroids are regulators of endothelin synthesis in ampullary oviductal epithelial cells.

Progesterone-mediated effects on gene expression and oocyte-cumulus complex transport in the mouse fallopian tube

BACKGROUND

The fallopian tube transports the gametes to the fertilization site and delivers the embryo to the uterus at the optimal time for implantation. Progesterone and the classical progesterone receptor are involved in regulating both tubal ciliary beating and muscular contractions, likely via both genomic and non-genomic actions.

METHODS

To provide more details of the underlying mechanisms, we investigated the effect of progesterone on gene expression in mice fallopian tubes in vitro at 20 min, 2 h and 8 h post progesterone treatment using microarray and/or quantitative PCR. In parallel, oocyte cumulus complex transport was investigated in ovulating mice that were injected with one of the progesterone receptor antagonists, Org 31710 or CDB2194.

RESULTS

Microarray analyses did not reveal any apparently regulated genes 20 min after progesterone treatment, consistent with the proposed non-genomic action of progesterone controlling ciliary beating. After 2 h, 11 genes were identified as up-regulated. Analyses using quantitative PCR at 2 h and 8 h showed a consistent up-regulation of endothelin1 and a down-regulation of its receptor Endothelin receptor A by progesterone. We also confirmed that treatment with progesterone receptor antagonists before ovulation accelerates the transport of the oocyte cumulus complex.

CONCLUSIONS

This is the first study showing that progesterone regulates the expression of endothelin1 and endothelin receptor A in the fallopian tube. Together with previous studies of the effects of endothelin on muscular contractions in the fallopian tube, the results from this study suggest that endothelin is a mediator of the progesterone-controlled effects on muscular contraction and eventually gamete transport in the fallopian tube.

Mating decreases plasma levels of TGFβ1 and regulates myosalpinx expression of TGFβ1/TGFBR3 in the rat

Mating shuts down a 2-methoxyestradiol (2ME)-dependent, non-genomic activity that is responsible for accelerating egg transport in the rat oviduct. The aims of this work were to investigate the role of TGFβ1 in this 2ME-reduced activity and to determine the effect of mating on the expression and distribution of TGFβ1 and its receptor TGFBR3 in the rat oviduct. We determined the level of TGFβ1 in the plasma and oviductal fluid at 1, 3, or 6 hr during Day 1 of the oestrous cycle in unmated or mated animals. We then examined if 2ME accelerates oviductal egg transport in unmated rats that were previously treated with a neutralizing TGFβ1 antibody. The expression of Tgfb1 and Tgfbr3 mRNA and the level and distribution of TGFBR3 protein in the oviduct were also determined at these time points. Mating decreased TGFβ1 in the plasma, but not in the oviductal fluid, whereas antibody neutralization of circulating TGFβ1 did not prevent the effect of 2ME on egg transport. Mating decreased Tgfb1 and hastened the increase in TGFBR3 abundance in the myosalpinx. These results indicate that mating decreased circulating levels of TGFβ1 without shutting down the non-genomic 2ME response that normally accelerates egg transport. Levels of Tgfb1 transcript and TGFBR3 protein, however, changed in the myosalpinx of mated rats, suggesting a role for mating-associated factors in the autocrine and paracrine effects of TGFβ in the oviduct.

Progesterone receptor-dependent regulation of genes in the oviducts of female mice

Oviducts play a critical role in gamete and embryo transport, as well as supporting early embryo development. Progesterone receptor (PGR) is a transcription factor highly expressed in oviductal cells, while its activating ligand, progesterone, surges to peak levels as ovulation approaches. Progesterone is known to regulate oviduct cilia beating and muscular contractions in vitro, but how PGR may mediate this in vivo is poorly understood. We used PGR null mice to identify genes potentially regulated by PGR in the oviducts during the periovulatory period. Histologically, oviducts from PGR null mice showed no gross structural or morphological defects compared with normal littermates. However, microarray analysis of oviducts at 8 h posthuman chorionic gonadotropin revealed >1,000 PGR-dependent genes. Using reverse-transcription polymerase chain reaction (RT-PCR) we selected 10 genes for validation based on their potential roles in oocyte/embryo transport and support. Eight genes were confirmed to be downregulated ( Adamts1, Itga8, Edn3, Prlr, Ptgfr, Des, Myocd, and Actg2) and one upregulated ( Agtr2) in PGR null oviducts. Expression of these genes was also assessed in oviducts of naturally cycling mice during ovulation and day 1 and day 4 of pregnancy. Adamts1, Itga8, Edn3, Prlr, and Ptgfr were significantly upregulated in oviducts at ovulation/mating. However, most genes showed basal levels of expression at other times. The exceptions were Prlr and Ptgfr, which showed pulsatile increases on day 1 and/or day 4 of pregnancy. This is the first, comprehensive study to elucidate putative PGR-regulated genes in the oviduct and reveals key downstream targets potentially mediating oocyte and embryo transport.

Endothelin-1 signalling controls early embryonic heart rate in vitro and in vivo

AIM

Spontaneous activity of embryonic cardiomyocytes originates from sarcoplasmic reticulum (SR) Ca(2+) release during early cardiogenesis. However, the regulation of heart rate during embryonic development is still not clear. The aim of this study was to determine how endothelin-1 (ET-1) affects the heart rate of embryonic mice, as well as the pathway through which it exerts its effects.

METHODS

The effects of ET-1 and ET-1 receptor inhibition on cardiac contraction were studied using confocal Ca(2+) imaging of isolated mouse embryonic ventricular cardiomyocytes and ultrasonographic examination of embryonic cardiac contractions in utero. In addition, the amount of ET-1 peptide and ET receptor a (ETa) and b (ETb) mRNA levels were measured during different stages of development of the cardiac muscle.

RESULTS

High ET-1 concentration and expression of both ETa and ETb receptors was observed in early cardiac tissue. ET-1 was found to increase the frequency of spontaneous Ca(2+) oscillations in E10.5 embryonic cardiomyocytes in vitro. Non-specific inhibition of ET receptors with tezosentan caused arrhythmia and bradycardia in isolated embryonic cardiomyocytes and in whole embryonic hearts both in vitro (E10.5) and in utero (E12.5). ET-1-mediated stimulation of early heart rate was found to occur via ETb receptors and subsequent inositol trisphosphate receptor activation and increased SR Ca(2+) leak.

CONCLUSION

Endothelin-1 is required to maintain a sufficient heart rate, as well as to prevent arrhythmia during early development of the mouse heart. This is achieved through ETb receptor, which stimulates Ca(2+) leak through IP3 receptors.

The onset of human ectopic pregnancy demonstrates a differential expression of miRNAs and their cognate targets in the Fallopian tube

Human ectopic pregnancy (EP) is a leading cause of pregnancy-related death, but the molecular basis underlying the onset of tubal EP is largely unknown. Female Dicer1 conditional knockout mice are infertile with dysfunctional Fallopian tube and have a different miRNA expression profile compared to wild-type mice, and we speculated that Dicer-mediated regulation of miRNA expression and specific miRNA-controlled targets might contribute to the onset of tubal EP. In the present study, we used microarray analysis and quantitative RT-PCR to examine the expression of miRNAs and core miRNA regulatory components in Fallopian tube tissues from women with EP. We found that the levels of DICER1, four miRNAs (let-7i, miR-149, miR-182, and miR-424), and estrogen receptor α distinguished the tubal implantation site from the non-implantation site. Computational algorithms and screening for interactions with the estrogen and progesterone receptor signaling pathways showed that the four miRNAs were predicted to target ten genes, including NEDD4, TAF15, and SPEN. Subsequent experiments showed differences in NEDD4 mRNA and protein levels between the implantation and non-implantation sites. Finally, we revealed that increases in smooth muscle cell NEDD4 and stromal cell TAF15, in parallel with a decrease in epithelial cell SPEN, were associated with tubal implantation. Our study suggests that changes in miRNA levels by the DICER-mediated miRNA-processing machinery result in aberrant expression of cell type-specific proteins that are potentially involved in the onset of tubal EP.

Analysis of circulating DNA distribution in pregnant and nonpregnant dairy cows

Circulating nucleic acids (CNAs) are free-floating, cell-free DNA and RNA molecules in the circulation of healthy and diseased humans and animals. The aim of this study was to identify differences in CNA distribution in serum samples from multiparous pregnant (n = 24) and nonpregnant (n = 16) dairy cows at different days of gestation (Days 0, 20, and 40). A modified serial analysis of gene expression procedure was used to generate concatemerized short sequence tags from isolated serum DNA. A total of 6.1 × 10(6) tags were recovered from analyzed samples (n = 40). Significant differences between the pregnant and nonpregnant groups were detected in chromosomal regions, protein-coding sequences, and single genes (P < 0.05). Approximately 23% (1.4 × 10(6) tags) of the total sequence pool were present exclusively in the analyzed serum samples of pregnant cows. Of these tag sequences, seven originated from genomic regions and 13 from repetitive elements. Comparative BLAST analysis identified the repetitive tags as BovB (non-long terminal repeat retrotransposons/long interspersed nuclear elements), Art2A, BovA2, and Bov-tA2 (short interspersed nuclear elements). To our knowledge, this is the first study to comprehensively characterize the circulating, cell-free DNA profile in sera from pregnant and nonpregnant cows across early gestation.

Oviductal, endometrial and embryonic gene expression patterns as molecular clues for pregnancy establishment

In higher animals, the beginning of new life and transfer of genetic material to the next generation occurs in the oviduct when two distinct gametes cells unite resulting in the formation of a zygote. The zygote then undergoes serial developmental processes in the oviduct and enters into the uterus where it faces challenges and scrutiny from the endometrial ecosystem. Thus, embryos that are able to establish an appropriate embryo-maternal dialogue are capable of developing to term whereas the incompetent ones can perish any time during the gestation period. Although several lines of evidences indicated that pregnancy loss is a multi-factorial phenomenon, the biochemical composition of the embryo and maternal environment are the main players to determine pregnancy outcome. Indeed, expression patterns of the genes are the driving forces that induce biochemical composition changes in embryo, oviduct and uterine environment. Thus, examining the molecular signals that are associated with oviductal or endometrial receptivity and embryo implantation is essential for establishing strategies to improve pregnancy success. Therefore, this review focuses on the contribution of oviduct and its transcriptome profile on early stage embryo development and the impact of endometrium and its transcriptome changes on peri and post embryo implantation. In addition, this paper integrates established facts about hormonal and molecular signatures associated with endometrial receptivity. Finally, the blastocyst and pre-conception endometrial gene expression profiles have been discussed in relation to the pregnancy outcome to highlight the potentials of blastocyst and pre-transfer endometrial transcriptome profile approach for selecting appropriate recipient and developmentally competent embryo.

Coordinate regulation of heterogeneous nuclear ribonucleoprotein dynamics by steroid hormones in the human fallopian tube and endometrium in vivo and in vitro

Heterogeneous nuclear ribonucleoproteins (hnRNPs), which are chromatin-associated RNA-binding proteins, participate in mRNA stability, transport, intracellular localization, and translation by acting as transacting factors. Several studies have shown that steroid hormones can regulate hnRNP expression. However, to date, the regulation of hnRNPs and their interactions with steroid hormone signaling in fallopian tubes and endometrium are not fully elucidated. In the present study, we determined whether hnRNP expression is regulated during the menstrual cycle and correlates with estrogen receptor (ER) and progesterone receptor (PR) levels in human fallopian tubes in vivo. Because of the limited availability of human tubal tissues for the research, we also explored the mechanisms of hnRNP regulation in human endometrium in vitro. Fallopian tissue was obtained from patients in the early, late, and postovulatory phases and the midsecretory phase and endometrial tissue from premenopausal and postmenopausal women undergoing hysterectomy. We measured expression of hnRNPs and assessed their intracellular localization and interactions with ERs and PRs. We also determined the effects of human chorionic gonadotropin, 17β-estradiol (E(2)), and progesterone (P(4)) on hnRNP expression. In fallopian tubes, mRNA and protein levels of hnRNP A1, AB, D, G, H, and U changed dynamically during ovulation and in the midsecretory phase. In coimmunolocation and coimmunoprecipitation experiments, hnRNPs interacted with each other and with ERs and PRs in fallopian tubes. After treatment with E(2) and/or P(4) to activate ERs and PRs, hnRNP A1, AB, D, G, and U proteins displayed overlapping but distinct patterns of regulation in the endometrium in vitro. Our findings expand the physiological repertoire of hnRNPs in human fallopian tubes and endometrium and suggest that steroid hormones regulate different hnRNPs directly by interacting with ERs and/or PRs or indirectly by binding other hnRNPs. Both actions may contribute to regulation of gene transcription.

Hematopoetic prostaglandin D synthase: an ESR1-dependent oviductal epithelial cell synthase

Oviductal disease is a primary cause of infertility, a problem that largely stems from excessive inflammation of this key reproductive organ. Our poor understanding of the mechanisms regulating oviductal inflammation restricts our ability to diagnose, treat, and/or prevent oviductal disease. Using mice, our objective was to determine the spatial localization, regulatory mechanism, and functional attributes of a hypothesized regulator of oviductal inflammation, the hematopoietic form of prostaglandin D synthase (HPGDS). Immunohistochemistry revealed specific localization of HPGDS to the oviduct's epithelium. In the isthmus, expression of HPGDS was consistent. In the ampulla, expression of HPGDS appeared dependent upon stage of the estrous cycle. HPGDS was expressed in the epithelium of immature and cycling mice but not in the oviducts of estrogen receptor α knockouts. Two receptor subtypes bind PGD₂: PGD₂ receptor and G protein-coupled receptor 44. Expression of mRNA for Ptgdr was higher in the epithelial cells (EPI) than in the stroma (P < 0.05), whereas mRNA for Gpr44 was higher in the stroma than epithelium (P < 0.05). Treatment of human oviductal EPI with HQL-79, an inhibitor of HPGDS, decreased cell viability (P < 0.05). Treatment of mice with HQL-79 increased mRNA for chemokine (C-C motif) ligands 3, 4, and 19; chemokine (C-X-C motif) ligands 11 and 12; IL-13 and IL-17B; and TNF receptor superfamily, member 1b (P < 0.02 for each mRNA). Overall, these results suggest that HPGDS may play a role in the regulation of inflammation and EPI health within the oviduct.

Cyclic regulation of apoptotic gene expression in the mouse oviduct

The oviduct is a dynamic structure whose function relies upon cyclic changes in the morphology of both ciliated and secretory luminal epithelial cells. Unfortunately, infection of these epithelial cells by sexually transmitted pathogens can lead to pelvic inflammatory disease, ectopic pregnancies and infertility. The disruption of normal, cyclic apoptosis in the oviducal epithelium appears to be a causal factor of oviducal pathology and therefore, these pathways represent a potential target for diagnosis and therapeutic intervention. The objective of this study was to determine the pattern of expression for apoptotic genes in the oviduct of the naturally cycling mouse, generating fundamental information that can be applied to the development of animal models for research and the identification of targets for disease intervention. Whole oviducts were collected from regular cycling mice killed at 1p.m. on each day of the oestrous cycle and the expression of 84 apoptotic genes determined by targeted PCR super-array. Intact and cleaved caspases were then evaluated by western blotting. The expression of mRNA for genes classified as pro-apoptotic (Bad, Bak1 and Bok) and anti-apoptotic (Bag3, Bnip2 and Xiap) was regulated by day (P < 0.05). Differences in the temporal expression of several p53-related genes (Trp53bp2, Trp53inp1 and Trp73), those specific to the TNF superfamily (Tnfrsf10 and Tnfsf10b) and one caspase (Casp14) were also observed (P < 0.05). The cleaved forms of Caspases-3, -6 and -12 were all detected throughout the oestrous cycle. These results represent the first pathway-wide analysis of apoptotic gene expression in the murine oviduct.

Methodology matters: IVF versus ICSI and embryonic gene expression

The use of assisted reproduction treatment, especially intracytoplasmic sperm injection (ICSI), is now linked to a range of adverse consequences, the aetiology of which remains largely undefined. Our objective of this study was to determine differences in gene expression of blastocysts generated by ICSI as well as ICSI with artificial oocyte activation (ICSI-A) versus the less manipulative IVF, providing fundamental genetic information that can be used to aid in the diagnosis or treatment of those adversely affected by assisted reproduction treatment, as well as stimulate research to further refine these techniques. Murine blastocysts were generated by ICSI, ICSI-A and IVF, and processed for a microarray-based analysis of gene expression. Ten blastocysts were pooled for each procedure and three independent replicates generated. The data were then processed to determine differential gene expression and to identify biological pathways affected by the procedures. In blastocysts derived by ICSI versus IVF, the expression of 197 genes differed (P < 0.01). In blastocysts derived by ICSI-A versus IVF and ICSI-A versus ICSI, the expression of 132 and 65 genes differed respectively (P < 0.01). Procedural-induced changes in genes regulating specific biological pathways revealed some consistency to known adverse consequences. Detailed investigation of procedure-specific dysfunction is therefore warranted.

Expression pattern of endothelin system components and localization of smooth muscle cells in the human pre-ovulatory follicle

BACKGROUND

Whether ovarian follicular rupture involves contractile activity or not has been debated for decades. Recently, study in the rodents has indicated that an endogenously produced potent vasoconstrictive peptide, endothelin-2 (EDN2), may induce follicular constriction immediately prior to ovulation. This study was aimed to systematically characterize the human ovarian endothelin system and localize smooth muscle cells to assess the possible involvement of contractile activity in human ovulation.

METHODS

This is a prospective experimental study. Study subjects were 20 women aged 20-38 years who underwent IVF owing to tubal or male factors. Expression patterns of messenger RNAs (mRNAs) for EDN1, EDN2, EDN3, endothelin-converting enzyme-1 (ECE1 and ECE2), endothelin receptor A (ET(A)) and ET(B) in the granulosa cells (GCs) and cumulus cells and endothelin peptide concentration in the pre-ovulatory follicles were measured at 36 h after hCG injection. In addition, localization of ovarian smooth muscle cells and endothelin receptor expression were determined in normal (non-IVF patient) ovaries.

RESULTS

Pre-ovulatory follicles express mRNA for EDN1 and EDN2, ECE1, ECE2, ET(A) and ET(B), but not EDN3, contain highly concentrated endothelin peptides (105.9 pg/ml) and are surrounded by theca externa that are made mostly of multicell layer non-vascular smooth muscle cells. ET(A) expression is localized in the smooth muscle cells of theca externa, theca interna and GC, whereas ET(B) expression is confined to theca interna.

CONCLUSIONS

Pre-ovulatory follicles contain highly concentrated endothelins and are surrounded by non-vascular smooth muscle cells that express endothelin receptor, suggesting involvement of endothelin-induced contractile action in ovulation in the human ovary.

Bioinformatic detection of E47, E2F1 and SREBP1 transcription factors as potential regulators of genes associated to acquisition of endometrial receptivity

BACKGROUND

The endometrium is a dynamic tissue whose changes are driven by the ovarian steroidal hormones. Its main function is to provide an adequate substrate for embryo implantation. Using microarray technology, several reports have provided the gene expression patterns of human endometrial tissue during the window of implantation. However it is required that biological connections be made across these genomic datasets to take full advantage of them. The objective of this work was to perform a research synthesis of available gene expression profiles related to acquisition of endometrial receptivity for embryo implantation, in order to gain insights into its molecular basis and regulation.

METHODS

Gene expression datasets were intersected to determine a consensus endometrial receptivity transcript list (CERTL). For this cluster of genes we determined their functional annotations using available web-based databases. In addition, promoter sequences were analyzed to identify putative transcription factor binding sites using bioinformatics tools and determined over-represented features.

RESULTS

We found 40 up- and 21 down-regulated transcripts in the CERTL. Those more consistently increased were C4BPA, SPP1, APOD, CD55, CFD, CLDN4, DKK1, ID4, IL15 and MAP3K5 whereas the more consistently decreased were OLFM1, CCNB1, CRABP2, EDN3, FGFR1, MSX1 and MSX2. Functional annotation of CERTL showed it was enriched with transcripts related to the immune response, complement activation and cell cycle regulation. Promoter sequence analysis of genes revealed that DNA binding sites for E47, E2F1 and SREBP1 transcription factors were the most consistently over-represented and in both up- and down-regulated genes during the window of implantation.

CONCLUSIONS

Our research synthesis allowed organizing and mining high throughput data to explore endometrial receptivity and focus future research efforts on specific genes and pathways. The discovery of possible new transcription factors orchestrating the CERTL opens new alternatives for understanding gene expression regulation in uterine function.

Endothelins in regulating ovarian and oviductal function

In the last 30 years, remarkable progress has been made in our understanding of the biological role of endothelins in the regulation of reproductive function and fertility. A peptide hormone identified for its ability to regulate blood pressure has now been shown as a potent mediator of several reproductive pathways. Ligand- and receptor-specific roles have been identified and/or postulated during follicular development and ovulation as well as in the function and regression of the corpus luteum. In this review we have attempted to organize endothelin-mediated ovarian processes in a process-specific manner, rather than compile a review of ligand- or isoform-specific actions. Further, we have included a discussion on "post-ovarian" or oviductal function, as well as the future directions that we believe will increase our understanding of endothelin biology as a whole.