Perlecan and Syndecan-4 in Uterine Tissues during the Early Pregnancy in Mice

Role of ADAM and ADAMTS Disintegrin and Metalloproteinases in Normal Pregnancy and Preeclampsia

Normal pregnancy (NP) involves intricate processes starting with egg fertilization, proceeding to embryo implantation, placentation and gestation, and culminating in parturition. These pregnancy-related processes require marked uteroplacental and vascular remodeling by proteolytic enzymes and metalloproteinases. A disintegrin and metalloproteinase (ADAM) and ADAM with thrombospondin motifs (ADAMTS) are members of the zinc-dependent family of proteinases with highly conserved protein structure and sequence homology, which include a pro-domain, and a metalloproteinase, disintegrin and cysteine-rich domain. In NP, ADAMs and ADAMTS regulate sperm-egg fusion, embryo implantation, trophoblast invasion, placental angiogenesis and spiral arteries remodeling through their ectodomain proteolysis of cell surface cytokines, cadherins and growth factors as well as their adhesion with integrins and cell-cell junction proteins. Preeclampsia (PE) is a serious complication of pregnancy characterized by new-onset hypertension (HTN) in pregnancy (HTN-Preg) at or after 20 weeks of gestation, with or without proteinuria. Insufficient trophoblast invasion of the uterine wall, inadequate expansive remodeling of the spiral arteries, reduced uteroplacental perfusion pressure, and placental ischemia/hypoxia are major initiating events in the pathogenesis of PE. Placental ischemia/hypoxia increase the release of reactive oxygen species (ROS), which lead to aberrant expression/activity of certain ADAMs and ADAMTS. In PE, abnormal expression/activity of specific ADAMs and ADAMTS that function as proteolytic sheddases could alter proangiogenic and growth factors, and promote the release of antiangiogenic factors and inflammatory cytokines into the placenta and maternal circulation leading to generalized inflammation, endothelial cell injury and HTN-Preg, renal injury and proteinuria, and further decreases in uteroplacental blood flow, exaggeration of placental ischemia, and consequently fetal growth restriction. Identifying the role of ADAMs and ADAMTS in NP and PE has led to a better understanding of the underlying molecular and vascular pathways, and advanced the potential for novel biomarkers for prediction and early detection, and new approaches for the management of PE.

Cell type-specific analysis of transcriptome changes in the porcine endometrium on Day 12 of pregnancy

BACKGROUND

Along with trophoblast elongation (Days 10 to 12), estradiol is secreted in increasing amounts for recognition of pregnancy. Endometrial secretions driven by ovarian progesterone and conceptus signals are essential for conceptus growth and development. Results of transcriptome analyses of whole endometrial tissue samples in the pig indicated the need for cell type-specific endometrial gene expression analysis for a better understanding of transcriptome changes associated with establishment of pregnancy.

RESULTS

The most distinct transcriptome profile and the majority of differentially expressed genes (DEGs) were identified in luminal epithelium (LE). Many DEGs were found only in the cell type-specific analysis. The functional classification of DEGs identified in specific endometrial cell types revealed various distinct functions and pathways. Genes related to immune activation, estrogen signaling pathway, embryo development, and cell proliferation were upregulated in LE of pregnant gilts. Genes involved in sterol biosynthetic and metabolic processes and extracellular matrix were upregulated in stroma. Genes associated with cell communication such as via exosomes and vesicles were found as differential in LE, glandular epithelium (GE), and stroma (S).

CONCLUSIONS

This study revealed that conceptus signals induce different transcriptomic regulations in the endometrial compartments/cell types related to their specific function during recognition and establishment of pregnancy.

Adamts 1, 4, 5, 8, and 9 in Early Pregnancies

INTRODUCTION

The aim of this study was to immunohistochemically investigate the presence and localization of ADAMTS 1, 4, 5, 8 and 9 in decidual and chorionic tissues in first trimester pregnancy losses.

MATERIALS AND METHODS

This study was conducted with early pregnancy failure decidual and chorionic tissue samples from 36 pregnant women in the first trimester of pregnancy (ongoing pregnancies, missed miscarriages, anembryonic pregnancies) Results: It was observed that the decidual and chorionic tissue levels of ADAMTS 1, 4, 5, and 8 in ongoing pregnancies were more intensely expressed when compared with miscarriages. ADAMTS 1 expression was not observed in the anembryonic pregnancies, ADAMTS 4, 5, and 8 were less intensely expressed. ADAMTS 9 showed no staining in any group.

CONCLUSION

ADAMTS 1 may be necessary during the decidualization and implantation stages of early normal pregnancy.

PARP1 during embryo implantation and its upregulation by oestradiol in mice

Pregnancy requires successful implantation of an embryo, which occurs during a restricted period defined as ‘receptivity of the endometrium’ and is influenced by the ovarian steroids progesterone and oestradiol. The role of poly(ADP-ribose)polymerase-1 (PARP1) in apoptosis is well established. However, it is also involved in cell differentiation, proliferation and tissue remodelling. Previous studies have described the presence of PARP in the uterus, but its exact role in embryo implantation is not yet elucidated. Hence, in this study, we studied the expression of PARP1 in the uterus during embryo implantation and decidualisation, and its regulation by ovarian steroids. Our results show upregulation of the native form of PARP1 (∼116 kDa) in the cytosolic and nuclear compartments of implantation and non-implantation sites at day 5 (0500 h), followed by downregulation at day 5 (1000 h), during the embryo implantation period. The transcript level of Parp1 was also augmented during day 5 (0500 h). Inhibition of PARP1 activity by the drug EB-47 decreased the number of embryo implantation sites and blastocysts at day 5 (1000 h). Further, cleavage of native PARP1 was due to the activity of caspase-3 during the peri-implantation stage (day 5 (0500 h)), and is also required for embryo implantation, as inhibition of its activity compromised blastocyst implantation. The native (∼116 kDa) and cleaved (∼89 kDa) forms of PARP1 were both elevated during decidualisation of the uterus. Furthermore, the expression level of PARP1 in the uterus was found to be under the control of the hormone oestrogen. Our results clearly demonstrate that PARP1 participates in the process of embryo implantation.

Heparin for assisted reproduction

BACKGROUND

Heparin as an adjunct in assisted reproduction (peri-implantation heparin) is given at or after egg collection or at embryo transfer during assisted reproduction. Heparin has been advocated to improve embryo implantation and clinical outcomes.  It has been proposed that heparin enhances the intra-uterine environment by improving decidualisation with an associated activation of growth factors and a cytokine expression profile in the endometrium that is favourable to pregnancy.

OBJECTIVES

To investigate whether the administration of heparin around the time of implantation (peri-implantation heparin) improves clinical outcomes in subfertile women undergoing assisted reproduction.

SEARCH METHODS

A comprehensive and exhaustive search strategy was developed in consultation with the Trials Search Co-ordinator of the Cochrane Menstrual Disorders and Subfertility Group (MDSG). The strategy was used in an attempt to identify all relevant studies regardless of language or publication status (published, unpublished, in press, and in progress). Relevant trials were identified from both electronic databases and other resources (last search 6 May 2013).

SELECTION CRITERIA

All randomised controlled trials (RCTs) were included where peri-implantation heparin was given during assisted reproduction. Peri-implantation low molecular weight heparin (LMWH) during IVF/ICSI was given at or after egg collection or at embryo transfer in the included studies. Live birth rate was the primary outcome.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and quality of trials and extracted relevant data. The quality of the evidence was evaluated using GRADE methods.

MAIN RESULTS

Three RCTs (involving 386 women) were included in the review.Peri-implantation LMWH administration during assisted reproduction was associated with a significant improvement in live birth rate compared with placebo or no LMWH (odds ratio (OR) 1.77, 95% confidence interval (CI) 1.07 to 2.90, three studies, 386 women, I(2) = 51%, very low quality evidence with high heterogeneity). There was also a significant improvement in the clinical pregnancy rate with use of LMWH (OR 1.61, 95% CI 1.03 to 2.53, three studies, 386 women, I(2) = 29%, very low quality evidence with low heterogeneity).However these findings should be interpreted with extreme caution as they were dependent upon the choice of statistical method: they were no longer statistically significant when a random-effects model was used.Adverse events were poorly reported in all included studies, with no comparative data available. However, LMWH did cause adverse effects including bruising, ecchymosis, bleeding, thrombocytopenia and allergic reactions. It appeared that these adverse effects were increased if heparin therapy was used over a longer duration.

AUTHORS' CONCLUSIONS

The results of this Cochrane review of three randomised controlled trials with a total of 386 women suggested that peri-implantation LMWH in assisted reproduction treatment (ART) cycles may improve the live birth rate in women undergoing assisted reproduction. However, these results were dependent on small low quality studies with substantial heterogeneity, and were sensitive to the choice of statistical model. There were side effects reported with use of heparin, including bruising and bleeding, and no reliable data on long-term effects. The results do not justify this use of heparin outside well-conducted research trials.These findings need to be further investigated with well-designed, adequately powered, double-blind, randomised, placebo-controlled, multicentre trials. Further investigations could also focus on the effects of the local (uterine) and not systemic application of heparin during ART.

Expression of ADAMTS1 mRNA in bovine endometrium and placenta during gestation

A disintegrin and metalloproteinase with thrombospondin motifs 1 (ADAMTS1) is a secreted protease. Through the regulation of extracellular matrix remodeling or developmental processes or both, ADAMTS1 is involved in several biological functions, including ovulation and embryo receptivity. However, the expression and possible role of ADAMTS1 in bovine endometrium is unknown. In this study, we analyzed ADAMTS1 mRNA expression in bovine endometrium during the estrous cycle, peri-implantation period, and at different stages of gestation by using quantitative real-time RT-PCR (qPCR) and in situ hybridization. The qPCR results indicated that the expression of ADAMTS1 mRNA was not affected by the day of the estrous cycle and was similar to cyclic levels on day 35 of gestation; however, the expression was more abundant in cotyledonary tissues of the placenta during late gestation. The in situ hybridization study showed that ADAMTS1 mRNA was detected mainly in uterine luminal epithelia and stromal cells during the estrous cycle and peri-implantation period. A disintegrin and metalloproteinase with thrombospondin motifs 1 mRNA was also expressed in the peri-implantation conceptus as well as in trophoblast cells, which include binucleate cells, and increased during late gestation. Furthermore, treatment of stromal cell with progesterone (300 nM) stimulated the expression of ADAMTS1 mRNA. This study indicates that ADAMTS1 participates in bovine endometrial remodeling, which is required for implantation and placental development in coordination with ovarian steroids.

The estrous cycle modulates small leucine-rich proteoglycans expression in mouse uterine tissues

In the pregnant mouse uterus, small leucine-rich proteoglycans (SLRPs) are drastically remodeled within a few hours after fertilization, suggesting that ovarian hormone levels modulate their synthesis and degradation. In this study, we followed by immunoperoxidase approach, the presence of four members of the SLRP family (decorin, lumican, biglycan, and fibromodulin) in the uterine tissues along the estrous cycle of the mouse. All molecules except fibromodulin, which predominates in the myometrium, showed a striking modulation in their distribution in the endometrial stroma, following the rise in the level of estrogen. Moreover, notable differences in the distribution of SLRPs were observed between superficial and deep stroma, as well as between the internal and external layers of the myometrium. Only biglycan and fibromodulin were expressed in the luminal and glandular epithelia. All four SLRPs were found in cytoplasmic granules of mononucleated cells. The pattern of distribution of the immunoreaction for these molecules in the uterine tissues was found to be estrous cycle-stage dependent, suggesting that these molecules undergo ovarian hormonal control and probably participate in the preparation of the uterus for decidualization and embryo implantation. In addition, this and previous results from our laboratory suggest the existence of two subpopulations of endometrial fibroblasts that may be related to the centrifugal development of the decidua. Anat Rec, 2008. (c) 2008 Wiley-Liss, Inc.

Collagen fibril organization in the pregnant endometrium of decorin-deficient mice

In the pregnant mouse endometrium, collagen fibrillogenesis is characterized by the presence of very thick collagen fibrils which are topographically located exclusively within the decidualized stroma. This dynamic biological process is in part regulated by the small leucine-rich proteoglycans decorin and biglycan. In the present study we utilized wild-type (Dcn(+/+)) and decorin-deficient (Dcn(-/-)) time-pregnant mice to investigate the evolution of non-decidualized and decidualized collagen matrix in the uterine wall of these animals. Ultrastructural and morphometric analyses revealed that the organization of collagen fibrils in the pregnant endometrium of both non-decidualized and decidualized stroma showed a great variability of shape and size, regardless of the genotype. However, the decidualized endometrium from Dcn(-/-) mice contained fibrils with larger diameter and more irregular contours as compared to the wild-type littermates. In the Dcn(-/-) animals, the proportion of thin (10-50 nm) fibrils was also higher as compared to Dcn(+/+) animals. On day 7 of pregnancy, biglycan was similarly localized in the decidualized endometrium in both genotypes. Lumican immunostaining was intense both in decidualized and non-decidualized stroma from Dcn(-/-) animals. The present results support previous findings suggesting that decorin participates in uterine collagen fibrillogenesis. In addition, we suggest that the absence of decorin disturbs the process of lateral assembly of thin fibrils, resulting in very thick collagen fibrils with irregular profiles. Our data further suggest that decorin, biglycan and lumican might play an interactive role in collagen fibrillogenesis in the mouse endometrium, a process modulated according to the stage of pregnancy.

Agrin pathway is controlled by leukemia inhibitory factor (LIF) in murine implantation

Agrin is the heparan sulfate proteoglycan (HSPG) that is well known as the molecule that aggregates acetylcholine receptor (AChR) through muscle specific kinase (MuSK) and rapsyn at neuromuscular junctions. HSPGs are spatiotemporally expressed in embryonic and maternal tissues during implantation. The present study examined the role of agrin in the mouse embryo using leukemia inhibitory factor (LIF)-deficient mice, which show complete sterility. Agrin was detected widely in the cytoplasm of uterine luminal epithelial cells at the third day of pregnancy (Day 3) and Day 4. At Day 5, agrin moved to the apical surface of the luminal epithelium. This migration was not found in LIF-deficient mice. AChR was also found in the apical surface of the uterine epithelium at Day 4 and Day 5 in normal mice. LIF-deficient mice did not show this pattern of expression. Only nAChR b1 subunit mRNA was increased at Day 5 in normal mice. Furthermore, acetylcholinesterase was active in the uterine stroma of normal mice throughout the implantation period and was exclusively active in the uterine epithelium at Day 4. Taken together, agrin signaling was activated in the uterus during embryo implantation in the mice. Here, we suggest that the agrin pathway is involved in closure of the uterine epithelium toward placentation.

Heparan sulfate proteoglycans and their binding proteins in embryo implantation and placentation

Complex interactions occur among embryonic, placental and maternal tissues during embryo implantation. Many of these interactions are controlled by growth factors, extracellular matrix and cell surface components that share the ability to bind heparan sulfate (HS) polysaccharides. HS is carried by several classes of cell surface and secreted proteins called HS proteoglycan that are expressed in restricted patterns during implantation and placentation. This review will discuss the expression of HS proteoglycans and various HS binding growth factors as well as extracellular matrix components and HS-modifying enzymes that can release HS-bound proteins in the context of implantation and placentation.

Granulated and non-granulated decidual prolactin-related protein-positive decidual cells in the pregnant mouse endometrium

PROBLEM

Identification of the cell types responsible for the synthesis of decidual prolactin-related protein (dPRP) in the pregnant mouse endometrium.

METHOD OF STUDY

Histochemistry and immunocytochemistry were used to determine peri-implantation dPRP and perlecan distribution in the mouse uterus.

RESULTS

We identified dPRP in pre-decidual and mature decidual cells from days 5 to 12 of pregnancy. On day 8, dPRP immunoreactivity was detected within cytoplasmic granules of a specific population of granulated decidual cells (GDCs). In mesometrial decidual cells, weak immunoreactivity was seen from days 7 to 14. Between days 11 and 14, dPRP was found in cytoplasm and in the extracellular matrix surrounding islands of spongiotrophoblast. Perlecan, a heparan sulfate proteoglycan, was co-localized with dPRP.

CONCLUSION

GDCs are a putative source of dPRP in pregnant mice. Co-localization of perlecan with dPRP suggests that the former acts as a dPRP reservoir and facilitates its paracrine effect in developing placental tissues.

Expression of syndecans, cell-cell interaction regulating heparan sulfate proteoglycans, within the human endometrium and their regulation throughout the menstrual cycle

OBJECTIVE

To evaluate the expression of syndecan-1, -2, -3, and -4 in different phases of eutopic endometrium of normal cycling women.

DESIGN

Prospective observational study.

SETTING

University-based research center for reproductive medicine.

PATIENT(S)

Twenty-nine healthy ovulatory volunteers.

INTERVENTION(S)

mRNA and protein expression of syndecan-1 to -4 in human endometrium.

MAIN OUTCOME MEASURE(S)

Real-time polymerase chain reaction of syndecan members and further characterization of mRNA expression of syndecan-1 and -4 with multiprobe RNase protection assays of epithelial and stromal cells after purification with antibody-coated magnetic beads. For confirmation of results, protein expression and localization using immunohistochemistry for syndecan-1 and -4 was performed.

RESULT(S)

All syndecans were expressed within human endometrium. Syndecan-1 and -4 proved to be significantly upregulated in whole endometrium during the secretory phase (2.73-fold and 2.85-fold, respectively). Using multiprobe RNase protection assays, a significant upregulation of mRNA was noted in epithelial cells during the secretory phase for both syndecan-1 and -4 (7.46-fold and 2.52-fold, respectively) and confirmed by immunohistochemistry.

CONCLUSION(S)

Cycle-dependent expression of syndecan-1 and -4 suggests that these adhesion proteins are involved in the regulation of the cycling endometrium.

Implication of ADAM-8, -9, -10, -12, -15, -17, and ADAMTS-1 in implantational remodeling of a mouse uterus

In the present study, whether the ADAM-8, -9, -10, -12, -15, -17, and ADAMTS-1 proteins might play a role in mouse uterus during periimplantation period was investigated. Immunoblotting analyses demonstrated that all ADAM proteins consistently appeared throughout days 1 to 8 of pregnancy but with a variation depending on the species of ADAM gene, the progression of pregnancy, and the site of the uterus. Immunohistochemical analyses indicated that ADAM proteins were localized in the luminal or glandular epithelial layers with a varying intensity depending on the species of ADAM and the progression of pregnancy. Particularly ADAM-8, -12, and -15, were predominantly located in the implantation site of the uterine tissues, whereas little or no protein was localized in the interimplantation site. Based upon these observations, it is suggested that the ADAMs might play an important role in the remodeling of the mouse uterus during the periimplantation period.