Secreted phosphoprotein 1 (osteopontin) is expressed by stromal macrophages in cyclic and pregnant endometrium of mice, but is induced by estrogen in luminal epithelium during conceptus attachment for implantation

Sexual dimorphism in placental development and function: Comparative physiology with an emphasis on the pig

Across mammalian species, it has been demonstrated that sex influences birth weight, with males being heavier than females; a characteristic that can be observed from early gestation. Male piglets are more likely to be stillborn and have greater preweaning mortality than their female littermates, despite the additional maternal investment into male fetal growth. Given the conserved nature of the genome between the sexes, it is hypothesized that these developmental differences between males and females are most likely orchestrated by differential placental adaptation. This review summarizes the current understanding of fetal sex-specific differences in placental and endometrial structure and function, with an emphasis on pathways found to be differentially regulated in the pig including angiogenesis, apoptosis, and proliferation. Given the importance of piglet sex in agricultural enterprises, and the potential for skewed litter sex ratios, it is imperative to improve understanding of the relationship between fetal sex and molecular signaling in both the placenta and endometria across gestation.

How do pre-pregnancy endometrial macrophages contribute to pregnancy?

Macrophages are professional phagocytes with a wide distribution in all tissues throughout the body. Macrophages play a crucial role in homeostasis and numerous physiological processes beyond innate and adaptive immunity, including cellular debris removal, metabolic regulation, tissue repair, and tissue remodeling. Uterine macrophages are a heterogeneous and highly plastic subset of immune cells regulated by the local microenvironment and, in addition to their anti-inflammatory and anti-infective functions, support the establishment and maintenance of pregnancy. Comprehensive reviews have summarized the role of decidual macrophages during pregnancy. However, the distribution of macrophages in the endometrium prior to pregnancy, their functional remodeling, and the knock-on effects on subsequent pregnancies have not been elucidated. In this review, we focus on 1) how the phenotypes of endometrial macrophages and their interactions with other endometrial cells indicate or contribute to the subsequent pregnancy, 2) the adaptive switching of endometrial macrophages during the initial establishment of pregnancy, 3) and the pregnancy complications and pregnancy-related disorders associated with endometrial macrophages.

Molecular Mechanism of Mouse Uterine Smooth Muscle Regulation on Embryo Implantation

Myometrium plays critical roles in multiple processes such as embryo spacing through peristalsis during mouse implantation, indicating vital roles of smooth muscle in the successful establishment and quality of implantation. Actin, a key element of cytoskeleton structure, plays an important role in the movement and contraction of smooth muscle cells (SMCs). However, the function of peri-implantation uterine smooth muscle and the regulation mechanism of muscle tension are still unclear. This study focused on the molecular mechanism of actin assembly regulation on implantation in smooth muscle. Phalloidin is a highly selective bicyclic peptide used for staining actin filaments (also known as F-actin). Phalloidin staining showed that F-actin gradually weakened in the CD-1 mouse myometrium from day 1 to day 4 of early pregnancy. More than 3 mice were studied for each group. Jasplakinolide (Jasp) used to inhibit F-actin depolymerization promotes F-actin polymerization in SMCs during implantation window and consequently compromises embryo implantation quality. Transcriptome analysis following Jasp treatment in mouse uterine SMCs reveals significant molecular changes associated with actin assembly. Tagln is involved in the regulation of the cell cytoskeleton and promotes the polymerization of G-actin to F-actin. Our results show that Tagln expression is gradually reduced in mouse uterine myometrium from day 1 to 4 of pregnancy. Furthermore, progesterone inhibits the expression of Tagln through the progesterone receptor. Using siRNA to knock down Tagln in day 3 SMCs, we found that phalloidin staining is decreased, which confirms the critical role of Tagln in F-actin polymerization. In conclusion, our data suggested that decreases in actin assembly in uterine smooth muscle during early pregnancy is critical to optimal embryo implantation. Tagln, a key molecule involved in actin assembly, regulates embryo implantation by controlling F-actin aggregation before implantation, suggesting moderate uterine contractility is conducive to embryo implantation. This study provides new insights into how the mouse uterus increases its flexibility to accommodate implanting embryos in the early stage of pregnancy.

Role of osteopontin (OPN) in uterine spiral artery remodeling

Uterine spiral artery (SpA) remodeling is critical for a successful pregnancy. The deficiency of SpA remodeling seriously affects the blood perfusion of the placenta, impacting the nutritional supply to the fetus and therefore fetal growth and development, which is one of the pathological causes of pregnancy related diseases. This process involves the interaction between all cells and related factors at the maternal-fetal interface, especially extravillous trophoblast cells (EVT), vascular smooth muscle cells (VSMCs) and decidual immune cells. Osteopontin (OPN), as a glycosylated protein, is widely localized in the extracellular matrix and participates in a variety of cellular activities such as migration, adhesion, differentiation and survival. OPN plays an important role in placental development, uterine decidualization and pregnancy success. This study focuses on the role of OPN in uterine spiral artery remodeling and its related molecular mechanism.

Establishment of Adenomyosis Organoids as a Preclinical Model to Study Infertility

Adenomyosis is related to infertility and miscarriages, but so far there are no robust in vitro models that reproduce its pathological features to study the molecular mechanisms involved in this disease. Endometrial organoids are in vitro 3D models that recapitulate the native microenvironment and reproduce tissue characteristics that would allow the study of adenomyosis pathogenesis and related infertility disorders. In our study, human endometrial biopsies from adenomyosis (n = 6) and healthy women (n = 6) were recruited. Organoids were established and hormonally differentiated to recapitulate midsecretory and gestational endometrial phases. Physiological and pathological characteristics were evaluated by immunohistochemistry, immunofluorescence, qRT-PCR, and ELISA. Secretory and gestational organoids recapitulated in vivo glandular epithelial phenotype (pan-cytokeratin, Muc-1, PAS, Laminin, and Ki67) and secretory and gestational features (α-tubulin, SOX9, SPP1, PAEP, LIF, and 17βHSD2 expression and SPP1 secretion). Adenomyosis organoids showed higher expression of TGF-β2 and SMAD3 and increased gene expression of SPP1, PAEP, LIF, and 17βHSD2 compared with control organoids. Our results demonstrate that organoids derived from endometria of adenomyosis patients and differentiated to secretory and gestational phases recapitulate native endometrial-tissue-specific features and disease-specific traits. Adenomyosis-derived organoids are a promising in vitro preclinical model to study impaired implantation and pregnancy disorders in adenomyosis and enable personalized drug screening.

Challenges and strategy in treatment with exosomes for cell-free-based tissue engineering in dentistry

In dentistry, problems of craniofacial, osteochondral, periodontal tissue, nerve, pulp or endodontics injuries, and osteoarthritis need regenerative therapy. The use of stem cells in dental tissue engineering pays a lot of increased attention, but there are challenges for its clinical applications. Therefore, cell-free-based tissue engineering using exosomes isolated from stem cells is regarded an alternative approach in regenerative dentistry. However, practical use of exosome is restricted by limited secretion capability of cells. For future regenerative treatment with exosomes, efficient strategies for large-scale clinical applications are being studied, including the use of ceramics-based scaffold to enhance exosome production and secretion which can resolve limited exosome secretory from the cells when compared with the existing methods available. Indeed, more research needs to be done on these strategies going forward.

Polymorphism of OPN and AREG Genes in Relation to Transcript Expression of a Panel of 12 Genes Controlling Reproduction Processes and Litter Size in Pigs

The aim of this study was to define the transcript expression of 12 genes, identify new polymorphisms in selected 2 genes and to estimate the association between the level of expression, gene polymorphism and litter size in sows. Two groups of sows were selected: 71 crossbred sows and 328 purebred sows. For transcript analysis endometrial tissue samples were collected, while blood was sampled for the purpose of DNA polymorphism analysis. For all animals data on litter size and weaned piglets were obtained. Transcript analysis of 12 genes was performed in the uterine endometrium of sows in the luteal and follicular phases. Eight out of 12 genes showed higher mRNA expression levels during the luteal phase (AREG, FABP3, IL1A, ITGAV, ITGB3, NMB, OPN, RBP4). In turn, higher expression levels in the follicular phase were observed for 4 genes (IL1B, PPARG, S100A8, SELL). Analysis of six new polymorphic sites within the OPN and AREG genes revealed the highest heterozygosity for OPNe6_Knoll, OPNp3_617 and AREGe2_317 polymorphisms and the lowest heterozygosity in the AREGe3_561 locus. Association analyses concerning transcript expression levels of the 12 genes and the OPN and AREG genotypes in the two groups of sows showed a significant relationship between the IL1A, ITGB3 transcript expression and the OPNe7_603 genotype also between OPNp3_617 genotype and ITGB3 transcript expression. With regard to the litter size and the number of weaned piglets a significant relation with the OPNp3_617, OPNe6_462 and AREGe2_317 genotypes was observed only in the purebred sows. Transcript expression of the genes encoding osteopontin and amphiregulin in the uterus of the sows affect reproductive traits by preparing the uterus for embryo reception.

SPP1 expression in the mouse uterus and placenta: Implications for implantation

Secreted phosphoprotein 1 [SPP1, also known as osteopontin (OPN)] binds integrins to mediate cell-cell and cell-extracellular matrix communication to promote cell adhesion, migration, and differentiation. Considerable evidence links SPP1 to pregnancy in several species. Current evidence suggests that SPP1 is involved in implantation and placentation in mice, but in vivo localization of SPP1 and in vivo mechanistic studies to substantiate these roles are incomplete and contradictory. We localized Spp1 mRNA and protein in the endometrium and placenta of mice throughout gestation, and utilized delayed implantation of mouse blastocysts to link SPP1 expression to the implantation chamber. Spp1 mRNA and protein localized to the endometrial luminal (LE), but not glandular epithelia (GE) in interimplantation regions of the uterus throughout gestation. Spp1 mRNA and protein also localized to uterine naturel killer (uNK) cells of the decidua. Within the implantation chamber, Spp1 mRNA localized only to intermittent LE cells, and to the inner cell mass. SPP1 protein localized to intermittent trophoblast cells, and to the parietal endoderm. These results suggest that SPP1: 1) is secreted by the LE at interimplantation sites for closure of the uterine lumen to form the implantation chamber; 2) is secreted by LE adjacent to the attaching trophoblast cells for attachment and invasion of the blastocyst; and 3) is not a component of histotroph secreted from the GE, but is secreted from uNK cells in the decidua to increase angiogenesis within the decidua to augment hemotrophic support of embryonic/fetal development of the conceptus.

Identification of potential crucial genes associated with early-onset preeclampsia via bioinformatic analysis

INTRODUCTION

Early-onset preeclampsia is a pregnancy complication associated with high maternal and perinatal morbidity, mortality. Intense efforts have been made to elucidate the pathogenesis, but the molecular mechanism is still elusive. This study aimed to identify potential key genes related to early-onset preeclampsia, and to obtain a better understanding of the molecular mechanisms of this disease.

METHODS

We performed a multi-step integrative bioinformatics analysis of microarray dataset GSE74341 downloaded from Gene Expression Omnibus (GEO) database including 7 early-onset preeclampsia and 5 gestational age matched normotensive controls. The differentially expressed genes (DEGs) were identified using the "limma" package, and their potential functions were predicted by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Furthermore, the protein-protein interaction network (PPI) was obtained from the STRING database and the PPI network was visualized by Cytoscape software. Then, hub modules and hub genes were screened out from the PPI network, and enrichment analysis was performed for them. Also, validation of hub genes expression in early-onset PE was down by using microarray dataset GSE44711.

RESULTS

A total of 628 DEGs (256 down- and 372 up-regulated) were identified in early-onset PE compared to controls. A total of 4 significant hub modules and 26 significant hub genes were identified.

CONCLUSION

In conclusion, the DEGs related to cell-cell or cell-extracellular matrix interaction (ITGA5, SPP1, LUM, VCAN, APP), placenta metabolic or oxidative stress (CCR7, NT5E, CYBB) were predicted to be newly potential crucial genes that may play significant roles in the pathogenesis of early-onset PE.

The Early Stages of Implantation and Placentation in the Pig

Pregnancy in pigs includes the events of conceptus (embryo/fetus and placental membranes) elongation, implantation, and placentation. Placentation in pigs is defined microscopically as epitheliochorial and macroscopically as diffuse. In general, placentation can be defined as the juxtapositioning of the endometrial/uterine microvasculature to the chorioallantoic/placental microvasculature to facilitate the transport of nutrients from the mother to the fetus to support fetal development and growth. Establishment of epitheliochorial placentation in the pig is achieved by: (1) the secretions of uterine glands prior to conceptus attachment to the uterus; (2) the development of extensive folding of the uterine-placental interface to maximize the surface area for movement of nutrients across this surface; (3) increased angiogenesis of the vasculature that delivers both uterine and placental blood and, with it, nutrients to this interface; (4) the minimization of connective tissue that lies between these blood vessels and the uterine and placental epithelia; (5) interdigitation of microvilli between the uterine and placental epithelia; and (6) the secretions of the uterine glands, called histotroph, that accumulate in areolae for transport though the placenta to the fetus. Placentation in pigs is not achieved by invasive growth of the placenta into the uterus. In this chapter, we summarize current knowledge about the major events that occur during the early stages of implantation and placentation in the pig. We will focus on the microanatomy of porcine placentation that builds off the excellent histological work of Amoroso and others and provide a brief review of some of the key physiological, cellular, and molecular events that accompany the development of "implantation" in pigs.

Association of foetal size and sex with porcine foeto-maternal interface integrin expression

Integrins regulate adhesion at the foeto-maternal interface by interacting with secreted phosphoprotein 1 (SPP1) and fibronectin (FN). It is hypothesised that impaired foetal growth of ‘runt’ piglets is linked to altered integrin signalling at the foeto-maternal interface. Placental and endometrial samples associated with the lightest and closest to mean litter weight (CTMLW) (gestational day (GD18, 30, 45, 60 and 90), of both sex (GD30, 45, 60 and 90) (n = 5–8 litters/GD), Large White × Landrace conceptuses or foetuses were obtained. The mRNA expression of the integrin subunits (ITG) ITGA2, ITGAV, ITGB1, ITGB3, ITGB5, ITGB6, ITGB8, SPP1 and FN was quantified by qPCR. Temporal changes in mRNA expression were observed, with different profiles in the two tissues. Endometrial ITGB1 (P ≤ 0.05, GD45) and SPP1 (P ≤ 0.05, all GD combined and GD60) expression was decreased in samples supplying the lightest compared to the CTMLW foetuses. Placentas supplying female foetuses had decreased expression of ITGB6 (GD45, P ≤ 0.05) and FN (GD90, P ≤ 0.05) compared to those supplying male foetuses. Endometrial samples supplying females had increased ITGB3 (P ≤ 0.05, GD60) and FN (P ≤ 0.05, GD30) expression and decreased SPP1 (P ≤ 0.05, GD60) expression compared to male foetuses. Correlations between mean within-gilt mRNA expression and percentage prenatal survival, number of live foetuses or conceptuses and percentage male foetuses were observed. This study has highlighted novel and dynamic associations between foetal size, sex and integrin subunit mRNA expression at the porcine foeto-maternal interface. Further studies should be performed to improve the understanding of the mechanisms behind these novel findings.

Transcriptomic analysis of the interaction of choriocarcinoma spheroids with receptive vs. non-receptive endometrial epithelium cell lines: an in vitro model for human implantation

PURPOSE

Several in vitro systems have been reported to model human implantation; however, the molecular dynamics of the trophoblast vs. the epithelial substrate during attachment have not been described. We have established an in vitro model which allowed us to dissect the transcriptional responses of the trophoblast and the receptive vs. non-receptive epithelium after co-culture.

METHODS

We established an in vitro system based on co-culture of (a) immortalized cells representing receptive (Ishikawa) or non-receptive (HEC-1-A) endometrial epithelium with (b) spheroids of a trophoblastic cell line (JEG-3) modified to express green fluorescent protein (GFP). After 48 h of co-culture, GFP+ (trophoblast cells) and GFP- cell fractions (receptive or non-receptive epithelial cells) were isolated by fluorescence-activated flow cytometry (FACS) and subjected to RNA-seq profiling and gene set enrichment analysis (GSEA).

RESULTS

Compared to HEC-1-A, the trophoblast challenge to Ishikawa cells differentially regulated the expression of 495 genes, which mainly involved cell adhesion and extracellular matrix (ECM) molecules. GSEA revealed enrichment of pathways related to cell division, cell cycle regulation, and metabolism in the Ishikawa substrate. Comparing the gene expression profile of trophoblast spheroids revealed that 1877 and 323 genes were upregulated or downregulated when co-cultured on Ishikawa substrates (compared to HEC-1-A), respectively. Pathways favorable to development, including tissue remodeling, organogenesis, and angiogenesis, were enhanced in the trophoblast compartment after co-culture of spheroids with receptive epithelium. By contrast, the co-culture with less receptive epithelium enriched pathways mainly related to trophoblast cell proliferation and cell cycle regulation.

CONCLUSIONS

Endometrial receptivity requires a transcriptional signature that determines the trophoblast response and drives attachment.

A potential role of galectin-1 in promoting mouse trophoblast stem cell differentiation

Galectin-1 is highly expressed in blastocysts and trophoblast giant cells during implantation, and dysregulated galectin-1 is associated with many pregnancy-related abnormalities. Elevated galectin-1 contributes to cancer cells invasion. Here, we found that galectin-1 is expressed in mouse oocytes, preimplantation embryos (all stages), and trophoblast stem (TS) cells. Peak levels of galectin-1 mRNA and protein were detected on day 4 and day 5 after the induction of TS cells differentiation. Overexpression of galectin-1 increased TS cells migration and invasion, whereas knockdown of galectin-1 attenuated these effects. Additionally, knockdown of galectin-1 in TS cells decreased the expression of matrix metalloproteinase (MMP) 2/9, ZEB-1, Snail, N-cadherin, TGF-β, Nodal, and phospho-Smad2/3, whereas the expression of E-cadherin was increased. In contrast, overexpression of galectin-1 in TS cells increased the expression of MMP2/9, ZEB-1, and N-cadherin, whereas the expression of E-cadherin was decreased. These findings suggest a potential role of galectin-1 in the differentiation of mouse TS cells.

ITGAV (alpha v integrins) bind SPP1 (osteopontin) to support trophoblast cell adhesion

Attachment of the conceptus trophoblast (Tr) to the uterine luminal epithelium (LE) is critical for successful implantation. This study determined whether alpha v (av) integrins (ITGAV) directly mediate porcine trophoblast cell adhesion to secreted phosphoprotein 1 (SPP1, also known as osteopontin (OPN)) and examined the temporal/spatial expression of ITGAV, beta 3 (b3, ITGB3) and beta 6 (b6, ITGB6) integrin subunits, and SPP1, at the uterine-placental interface of pigs. Knockdown of ITGAV in porcine Tr (pTr2) cells by siRNA reduced pTr2 attachment to SPP1. In situ hybridization confirmed the presence of ITGAV, ITGB3 and ITGB6 mRNAs in uterine LE and conceptus Tr between Days 9 and 60 of gestation, with no change in the magnitude of expression over the course of pregnancy. Exogenous E2 or P4 did not affect ITGAV, ITGB3 and ITGB6 mRNA expression in the uteri of ovariectomized gilts. Immunofluorescence identified ITGAV, ITGB3 and SPP1 proteins in large aggregates at the uterine LE-placental Tr/chorion interface on Day 25, but aggregates were no longer observed by Day 50 of gestation. These results are the first to directly demonstrate that pTr2 cells engage ITGAV-containing integrin receptors to adhere to SPP1 and suggest that mechanical forces generated by tethering elongating conceptuses to uterine LE leads to assembly of focal adhesions containing ITGAV and SPP1; however, as placentation progresses, subsequent folding/interdigitation at the uterine-placental interface disperses mechanical forces resulting in the loss of focal adhesions.

Early matrix metalloproteinase-9 inhibition post-myocardial infarction worsens cardiac dysfunction by delaying inflammation resolution

Matrix metalloproteinase-9 (MMP-9) is robustly elevated in the first week post-myocardial infarction (MI). Targeted deletion of the MMP-9 gene attenuates cardiac remodeling post-MI by reducing macrophage infiltration and collagen accumulation through increased apoptosis and reduced inflammation. In this study, we used a translational experimental design to determine whether selective MMP-9 inhibition early post-MI would be an effective therapeutic strategy in mice. We enrolled male C57BL/6J mice (3-6months old, n=116) for this study. Mice were subjected to coronary artery ligation. Saline or MMP-9 inhibitor (MMP-9i; 0.03μg/day) treatment was initiated at 3h post-MI and the mice were sacrificed at day (D) 1 or 7 post-MI. MMP-9i reduced MMP-9 activity by 31±1% at D1 post-MI (p<0.05 vs saline) and did not affect survival or infarct area. Surprisingly, MMP-9i treatment increased infarct wall thinning and worsened cardiac function at D7 post-MI. While MMP-9i enhanced neutrophil infiltration at D1 and macrophage infiltration at D7 post-MI, CD36 levels were lower in MMP-9i compared to saline, signifying reduced phagocytic potential per macrophage. Escalation and prolongation of the inflammatory response at D7 post-MI in the MMP-9i group was evident by increased expression of 18 pro-inflammatory cytokines (all p<0.05). MMP-9i reduced cleaved caspase 3 levels at D7 post-MI, consistent with reduced apoptosis and defective inflammation resolution. Because MMP-9i effects on inflammatory cells were significantly different from previously observed MMP-9 null mechanisms, we evaluated pre-MI (baseline) systemic differences between C57BL/6J and MMP-9 null plasma. By mass spectrometry, 34 plasma proteins were significantly different between groups, revealing a previously unappreciated altered baseline environment pre-MI when MMP-9 was deleted. In conclusion, early MMP-9 inhibition delayed inflammation resolution and exacerbated cardiac dysfunction, highlighting the importance of using translational approaches in mice.

Placental Growth Factor Is Secreted by the Human Endometrium and Has Potential Important Functions during Embryo Development and Implantation

Embryo implantation requires synchronized dialogue between the receptive endometrium and activated blastocyst via locally produced soluble mediators. During the mid-secretory (MS) phase of the menstrual cycle, increased glandular secretion into the uterine lumen provides important mediators that modulate the endometrium and support the conceptus during implantation. Previously we demonstrated the importance of vascular endothelial growth factor (VEGF) in the human uterus, particularly with respect to embryo implantation. In the current study, proteomic analysis of human uterine lavage fluid identified the presence of placental growth factor (PlGF) a homolog of VEGF, that binds the VEGF receptor 1 (VEGFR1). Analysis of immunostaining for PlGF in human endometrial tissue across the menstrual cycle (from both fertile and infertile women) revealed PlGF was predominantly localised to glandular and luminal epithelial cells, with staining in the decidualising stromal cells surrounding the maternal spiral arteries in the secretory phase of the menstrual cycle. Immunoreactive PlGF was also detected in subpopulations of endometrial leukocytes. Functional studies demonstrated that culturing mouse embryos with recombinant human (rh)PlGF enhanced blastocyst cell number and outgrowth. Furthermore, treatment of human endometrial epithelial cells (EEC) with rhPlGF enhanced EEC adhesion. Taken together, these data demonstrate that PlGF is abundant in the human endometrium, and secreted into the uterine lumen where it mediates functional changes in cellular adhesion with important roles in implantation.

Microarray Gene Expression Analysis to Evaluate Cell Type Specific Expression of Targets Relevant for Immunotherapy of Hematological Malignancies

Cellular immunotherapy has proven to be effective in the treatment of hematological cancers by donor lymphocyte infusion after allogeneic hematopoietic stem cell transplantation and more recently by targeted therapy with chimeric antigen or T-cell receptor-engineered T cells. However, dependent on the tissue distribution of the antigens that are targeted, anti-tumor responses can be accompanied by undesired side effects. Therefore, detailed tissue distribution analysis is essential to estimate potential efficacy and toxicity of candidate targets for immunotherapy of hematological malignancies. We performed microarray gene expression analysis of hematological malignancies of different origins, healthy hematopoietic cells and various non-hematopoietic cell types from organs that are often targeted in detrimental immune responses after allogeneic stem cell transplantation leading to graft-versus-host disease. Non-hematopoietic cells were also cultured in the presence of IFN-γ to analyze gene expression under inflammatory circumstances. Gene expression was investigated by Illumina HT12.0 microarrays and quality control analysis was performed to confirm the cell-type origin and exclude contamination of non-hematopoietic cell samples with peripheral blood cells. Microarray data were validated by quantitative RT-PCR showing strong correlations between both platforms. Detailed gene expression profiles were generated for various minor histocompatibility antigens and B-cell surface antigens to illustrate the value of the microarray dataset to estimate efficacy and toxicity of candidate targets for immunotherapy. In conclusion, our microarray database provides a relevant platform to analyze and select candidate antigens with hematopoietic (lineage)-restricted expression as potential targets for immunotherapy of hematological cancers.

The Multifaceted Actions of Leukaemia Inhibitory Factor in Mediating Uterine Receptivity and Embryo Implantation

Embryo implantation is mediated by the combined actions of the ovarian hormones E2 and P4 on the uterus. In addition, the pro-inflammatory cytokine, leukaemia inhibitory factor (LIF), plays a pivotal role in regulating uterine receptivity. LIF is expressed in the endometrial glands and has a robust action on the uterine luminal epithelium (LE). In mice, LIF is induced by nidatory E2 and functions to convert the LE from a non-receptive to an embryo-responsive state. LIF mediates its actions by activating the JAK-STAT pathway specifically in the LE. Activation of JAK-STAT pathway results in the induction of many additional pathways, including some 40 +  transcription factors, many of which initiate a cascade of changes affecting epithelial polarity, epithelial-mesenchymal interactions, angiogenesis, stromal cell decidualization, and inhibiting cell proliferation. This review discusses the role of LIF and the recent analysis of its action on the uterine LE in regulating endometrial receptivity and implantation.

Osteopontin-expressing macrophages in non-small cell lung cancer predict survival

BACKGROUND

Tumor-associated macrophages (TAMs) are a major component of leukocyte infiltration in the tumor microenvironment. Osteopontin is related to tumor metastasis and proliferation. Osteopontin is expressed not only by tumor cells but also by TAMs. The purpose of the current study was to assess the prognostic significance of osteopontin expressed by TAMs (TOPN) in patients with non-small cell lung cancer.

METHODS

Tissue microarray was used to detect the expression of TOPN, TAMs, and microvascular density in 159 patients with non-small cell lung cancer undergoing complete pulmonary resection in our hospital between 2003 and 2006. The correlations between TOPN, TAMs, and clinicopathologic data were analyzed with χ(2) tests. Quantitation of TAMs or TOPN and microvascular density analyses was performed using Bonferroni correction and the Student's t test. The prognostic value of TOPN was evaluated by univariate Kaplan-Meier survival analysis and multivariate Cox proportional hazard model analysis.

RESULTS

In the recurrence and metastasis group, microvascular density was higher than that in the control group (14.4 ± 1.06 versus 8.9 ± 1.02; p = 0.0002). In the TOPN-positive group, microvascular density was increased compared with that in the TOPN-negative group (14.3 ± 1.37 versus 10.7 ± 0.91; p = 0.0273). Osteopontin expressed by TAMs was an independent predictor for overall survival (p = 0.017) and disease-free survival (p < 0.001), especially for stage I non-small cell lung cancer. The 6-year overall and disease-free survival rates in TOPN-positive patients were 22.64% and 16.98%, respectively, which were significantly lower than those of TOPN-negative patients (50.00% and 39.62%, respectively).

CONCLUSIONS

Osteopontin expressed by TAMs is a valuable independent predictor of tumor recurrence and survival in patients with non-small cell lung cancer.

Osteopontin: a leading candidate adhesion molecule for implantation in pigs and sheep

Osteopontin (OPN; also known as Secreted Phosphoprotein 1, SPP1) is a secreted extra-cellular matrix (ECM) protein that binds to a variety of cell surface integrins to stimulate cell-cell and cell-ECM adhesion and communication. It is generally accepted that OPN interacts with apically expressed integrin receptors on the uterine luminal epithelium (LE) and conceptus trophectoderm to attach the conceptus to the uterus for implantation. Research conducted with pigs and sheep has significantly advanced understanding of the role(s) of OPN during implantation through exploitation of the prolonged peri-implantation period of pregnancy when elongating conceptuses are free within the uterine lumen requiring extensive paracrine signaling between conceptus and endometrium. This is followed by a protracted and incremental attachment cascade of trophectoderm to uterine LE during implantation, and development of a true epitheliochorial or synepitheliochorial placenta exhibited by pigs and sheep, respectively. In pigs, implanting conceptuses secrete estrogens which induce the synthesis and secretion of OPN in adjacent uterine LE. OPN then binds to αvβ6 integrin receptors on trophectoderm, and the αvβ3 integrin receptors on uterine LE to bridge conceptus attachment to uterine LE for implantation. In sheep, implanting conceptuses secrete interferon tau that prolongs the lifespan of CL. Progesterone released by CL then induces OPN synthesis and secretion from the endometrial GE into the uterine lumen where OPN binds integrins expressed on trophectoderm (αvβ3) and uterine LE (identity of specific integrins unknown) to adhere the conceptus to the uterus for implantation. OPN binding to the αvβ3 integrin receptor on ovine trophectoderm cells induces in vitro focal adhesion assembly, a prerequisite for adhesion and migration of trophectoderm, through activation of: 1) P70S6K via crosstalk between FRAP1/MTOR and MAPK pathways; 2) MTOR, PI3K, MAPK3/MAPK1 (Erk1/2) and MAPK14 (p38) signaling to stimulate trohectoderm cell migration; and 3) focal adhesion assembly and myosin II motor activity to induce migration of trophectoderm cells. Further large in vivo focal adhesions assemble at the uterine-placental interface of both pigs and sheep and identify the involvement of sizable mechanical forces at this interface during discrete periods of trophoblast migration, attachment and placentation in both species.

OPN induces FoxM1 expression and localization through ERK 1/2, AKT, and p38 signaling pathway in HEC-1A cells

Mammalian embryo implantation is an extremely complex process and requires endometrial receptivity. In order to establish this receptivity, sequential proliferation and differentiation during the menstrual cycle is necessary. Forkhead box M1 (FoxM1) is described as a major oncogenic transcription factor in tumor initiation, promotion and progression. According to these functions, we believe that FoxM1 should also play an essential role in embryo implantation. Osteopontin (OPN), an adhesion molecule, has been studied extensively in reproduction. In this study, we observed the expression and distribution of FoxM1 during the proliferative-phase and secretory-phase human endometrium and the pre-implantation mouse uterus firstly. Then we observed the relationship between OPN and FoxM1. Our results showed that FoxM1 was mainly distributed in glandular epithelium. OPN increased the expression of FoxM1 in the human uterine epithelial cell line HEC-1A cells in a time- and concentration-dependent manner. OPN regulates FoxM1 to influence HEC-1A cell proliferation through extracellular regulated protein kinases (ERK 1/2), protein kinase B (PKB, AKT), and the p38 mitogen activated protein kinases (p38MAPK, p38) signaling pathway. Inhibition of ERK 1/2, AKT and p38 suppressed OPN-induced FoxM1 expression and location. Our data indicate that FoxM1 might be regulated by OPN to influence endometrial proliferation to establish endometrial receptivity.

Osteopontin is expressed in the mouse uterus during early pregnancy and promotes mouse blastocyst attachment and invasion in vitro

Embryo implantation into the maternal uterus is a decisive step for successful mammalian pregnancy. Osteopontin (OPN) is a member of the small integrin-binding ligand N-linked glycoprotein family and participates in cell adhesion and invasion. In this study, we showed that Opn mRNA levels are up-regulated in the mouse uterus on day 4 and at the implantation sites on days 5 and 8 of pregnancy. Immunohistochemistry localized the OPN protein to the glandular epithelium on day 4 and to the decidual zone on day 8 of pregnancy. OPN mRNA and proteins are induced by in vivo and in vitro decidualization. OPN expression in the endometrial stromal cells is regulated by progesterone, a key regulator during decidualization. As a secreted protein, the protein level of OPN in the uterine cavity is enriched on day 4, and in vitro embryo culturing has indicated that OPN can facilitate blastocyst hatching and adhesion. Knockdown of OPN attenuates the adhesion and invasion of blastocysts in mouse endometrial stromal cells by suppressing the expression and enzymatic activity of matrix metalloproteinase-9 in the trophoblast. Our data indicated that OPN expression in the mouse uterus during early pregnancy is essential for blastocyst hatching and adhesion and that the knockdown of OPN in mouse endometrial stroma cells could lead to a restrained in vitro trophoblast invasion.

Uterine micro-environment and estrogen-dependent regulation of osteopontin expression in mouse blastocyst

Embryo implantation is a highly synchronized bioprocess between an activated blastocyst and a receptive uterus. In mice, successful implantation relies on the dynamic interplay of estrogen and progesterone; however, the key mediators downstream of these hormones that act on blastocyst competency and endometrium receptivity acquisition are largely unknown. In this study, we showed that the expression of osteopontin (OPN) in mouse blastocysts is regulated by ovarian estrogen and uterine micro-environment. OPN mRNA is up-regulated in mouse blastocyst on day 4 of pregnancy, which is associated with ovarian estrogen secretion peak. Hormone treatment in vivo demonstrated that OPN expression in a blastocyst is regulated by estrogen through an estrogen receptor (ER). Our results of the delayed and activated implantation model showed that OPN expression is induced after estrogen injection. While estrogen treatment during embryo culture in vitro showed less effect on OPN expression, the tubal ligation model on day 3 of pregnancy confirmed that the regulation of estrogen on OPN expression in blastocyst might, through some specific cytokines, have existed in a uterine micro-environment. Collectively, our study presents that estrogen regulates OPN expression and it may play an important role during embryo implantation by activating blastocyst competence and facilitating the endometrium acceptable for active blastocyst.

Endometrial inflammation and effect on implantation improvement and pregnancy outcome

Implantation failure, which is presently the major barrier in human fertility, is attributed, in many cases, to the failure of the uterus to acquire receptivity. The transition into a receptive uterus includes cellular changes in the endometrium and the modulated expression of different cytokines, growth factors, transcription factors, and prostaglandins. These molecules partake in the generation of an inflammatory response followed by the recruitment of immune cells. These cells have shown to be involved in the maternal immune tolerance toward the implanted embryo as well as in the maternal–fetus interaction during pregnancy. Most of the accumulated evidence indicates that embryo implantation is associated with an active Th1 inflammatory response while a Th2-humoral inflammation is required for pregnancy maintenance. Yet, recent findings suggest that a Th1 inflammatory response is also necessary for the acquisition of uterine receptivity. This notion was originally suggested by reports from our and other clinical centers worldwide that IVF patients with repeated implantation failure subjected to endometrial biopsy exhibit a substantial improvement in their chances to conceive. These findings, followed by the demonstration of an elevated pro-inflammatory cytokine/chemokine expression, as well as an increased abundance of immune cells, in the endometrium of these patients, raised the idea that acquisition of uterine receptivity is closely associated with an inflammatory response. This review summarizes the molecular and biochemical evidence that confirm this notion and proposes a mechanism by which injury-induced inflammation improves uterine receptivity and the subsequent pregnancy outcome.

Estrogen-dependent uterine secretion of osteopontin activates blastocyst adhesion competence

Embryo implantation is a highly orchestrated process that involves blastocyst-uterine interactions. This process is confined to a defined interval during gestation referred to as the "window of embryo implantation receptivity". In mice this receptive period is controlled by ovarian estrogen and involves a coordination of blastocyst adhesion competence and uterine receptivity. Mechanisms coordinating the acquisition of blastocyst adhesion competence and uterine receptivity are largely unknown. Here, we show that ovarian estrogen indirectly regulates blastocyst adhesion competence. Acquisition of blastocyst adhesion competence was attributed to integrin activation (e.g. formation of adhesion complexes) rather than de novo integrin synthesis. Osteopontin (OPN) was identified as an estrogen-dependent uterine endometrial gland secretory factor responsible for activating blastocyst adhesion competence. Increased adhesion complex assembly in OPN-treated blastocysts was mediated through focal adhesion kinase (FAK)- and phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathways. These findings define for the first time specific regulatory components of an estrogen-dependent pathway coordinating blastocyst adhesion competence and uterine receptivity.

Extracellular matrix proteins secreted from both the endometrium and the embryo are required for attachment: a study using a co-culture model of rat blastocysts and Ishikawa cells

Integrins are expressed in a highly regulated manner at the maternal-fetal interface during implantation. However, the significance of extracellular matrix (ECM) ligands during the integrin-mediated embryo attachment to the endometrium is not fully understood. Thus, the distribution of fibronectin in the rat uterus and blastocyst was studied at the time of implantation. Fibronectin was absent in the uterine luminal epithelial cells but was intensely expressed in the trophoblast cells and the inner cell mass suggesting that fibronectin secreted from the blastocyst may be a possible bridging ligand for the integrins expressed at the maternal-fetal interface. An Arg-Gly-Asp (RGD) peptide was used to block the RGD recognition sites on integrins, and the effect on rat blastocyst attachment to Ishikawa cells was examined. There was a significant reduction in blastocyst attachment when either the blastocysts or the Ishikawa cells were pre-incubated with the RGD-blocking peptide. Thus, successful attachment of the embryo to the endometrium requires the interaction of integrins on both the endometrium and the blastocyst with the RGD sequence of ECM ligands, such as fibronectin. Pre-treatment of both blastocysts and Ishikawa cells with the RGD peptide also inhibited blastocyst attachment, but not completely, suggesting that ECM bridging ligands that do not contain the RGD sequence are also involved in embryo attachment.

Osteopontin increases the expression of β1, 4-galactosyltransferase-I and promotes adhesion in human RL95-2 cells

Beta1, 4-Galactosyltransferase-I (β1, 4-GalT-I), which transfers galactose from UDP-Gal to N-acetylglucosamine and N-acetylglucosamine-terminated oligosaccharides of N- and O-linked glycans in a β(1-4) linkage, plays a critical role in cell adhesion, sperm-egg recognition, neurite growth, and tumor cell migration and invasion. Our previously experiments also show that β1, 4-GalT-I was up-regulated by estrogens and some important cytokines of embryo implantation especially Interleukin-1 (IL-1), TGF-α and Leukemia Inhibitory Factor (LIF) in endometrial cells. In the receptive phase human uterus, osteopontin (OPN) is the most highly up-regulated extracellular matrix/adhesion molecule/cytokine. In this study, we demonstrated the correlated expression of OPN and β1, 4-GalT-I in endometrium during early pregnancy, and recombinant human OPN (rhOPN) protein induced the β1, 4-GalT-I up-regulation in RL95-2 cells. Inhibition of MEK/ERK, PI3K/AKT and NF-κB suppressed rhOPN-induced β1, 4-GalT-I expression. In addition, rhOPN promoted the adhesion of blastocysts cells in vitro in β1, 4-GalT-I-dependent manner. Moreover, the adhesion is greatly inhibited when β1, 4-GalT-I was blocked with the specific antibody. Taken together, our data suggest that β1, 4-GalT-I provides a mechanism to bridge embryo to endometrium during implantation.

Analysis of fertility-related soluble mediators in human uterine fluid identifies VEGF as a key regulator of embryo implantation

Embryo implantation requires synchronized dialogue between the receptive endometrium and activated blastocyst via locally produced soluble mediators. During the midsecretory (MS) phase of the menstrual cycle, increased glandular secretion into the uterine lumen contains important mediators that modulate the endometrium and support the conceptus during implantation. This study aimed first to identify the growth factor and cytokine profile of human uterine fluid from fertile women during the midproliferative (MP; nonreceptive) and MS (receptive) phases of the cycle, and from women with unexplained infertility during the MS phase. The second aim was to determine important functions of endometrial secretions for embryo implantation. Analysis of uterine fluid using quantitative Luminex assays revealed the presence of over 30 cytokines and growth factors, of which eight [platelet-derived growth factor-AA, TNF-B, soluble IL-2 receptor-A, Fms-like tyrosine kinase 3 ligand, soluble CD40 ligand, IL-7, interferon-A2, and chemokine (C-X-C motif) ligand 1-3] were previously unknown in human uterine fluid. Comparison of the fertile MP, MS, and infertile MS cohorts revealed vascular endothelial growth factor (VEGF) levels are significantly reduced in uterine fluid during the MS phase in women with unexplained infertility compared with fertile women. Functional studies demonstrated that culturing mouse embryos with either MS-phase uterine fluid from fertile women or recombinant human VEGF significantly enhanced blastocyst outgrowth. Furthermore, treatment of human endometrial epithelial cells with uterine fluid or recombinant human VEGF-A significantly increased endometrial epithelial cell adhesion. Taken together, our data support the concept that endometrial secretions, including VEGF, play important roles during implantation. Identifying the soluble mediators in human uterine fluid and their actions during implantation provides insight into interactions essential for establishing pregnancy, fertility markers, and infertility treatment options.

Integrin β3 in rat blastocysts and epithelial cells is essential for implantation in vitro: studies with Ishikawa cells and small interfering RNA transfection

BACKGROUND

Integrins are involved in the process of embryo-endometrium interaction during implantation. We investigated the localization of integrin β3 in the rat blastocyst and Ishikawa cells using an in vitro co-culture model of implantation.

METHODS

Zona pellucida-free rat blastocysts were co-cultured with the Ishikawa cells (endometrial adenocarcinoma cell line) to observe the attachment between the embryo and endometrium. Immunofluorescence staining was used to investigate the localization of integrin β3 in rat embryos at different stages of development (each n= 3 embryos) and at the embryo/endometrium interface, observed by confocal microscopy. The Ishikawa cells were transfected with integrin β3 small interfering RNA (siRNA) for 48 h and then co-cultured with Day 5 rat blastocysts to observe the effect on attachment.

RESULTS

Integrin β3 staining in the rat embryos increased at the blastocyst stage being highly concentrated in the cytoplasm of trophoblast cells (n= 9 embryos). Integrin β3 was localized on the apical surface of the Ishikawa cells (n= 3 experiments). However, integrin β3 relocated to the apical membrane of trophoblast cells in response to attachment to Ishikawa cells (n= 6 embryos). Moreover, when Ishikawa cells were transfected with integrin β3 siRNA, blastocyst attachment was significantly reduced compared with those transfected with control siRNA (16.7 versus 92.3%, respectively, P< 0.05).

CONCLUSIONS

Integrin β3, localized apically in the blastocyst and the Ishikawa cells, is important during initial attachment of the blastocyst to endometrial cells. This study provides further evidence of the importance of integrins during implantation and may aid in elucidating the molecular mechanism of implantation failure and infertility in women.

Osteopontin in macrophage function

The secreted phosphorylated protein osteopontin (OPN) is expressed in a variety of tissues and bodily fluids, and is associated with pathologies including tissue injury, infection, autoimmune disease and cancer. Macrophages are ubiquitous, heterogeneous cells that mediate aspects of cell and tissue damage in all these pathologies. Here, the role of OPN in macrophage function is reviewed. OPN is expressed in macrophage cells in multiple pathologies, and the regulation of its expression in these cells has been described in vitro. The protein has been implicated in multiple functions of macrophages, including cytokine expression, expression of inducible nitric oxide synthase, phagocytosis and migration. Indeed, the role of OPN in cells of the macrophage lineage might underlie its physiological role in many pathologies. However, there are numerous instances where the published literature is inconsistent, especially in terms of OPN function in vitro. Although the heterogeneity of OPN and its receptors, or of macrophages themselves, might underlie some of these inconsistencies, it is important to understand the role of OPN in macrophage biology in order to exploit its function therapeutically.

Contraceptive vaccines targeting factors involved in establishment of pregnancy

Current methods of contraception lack specificity and are accompanied with serious side effects. A more specific method of contraception is needed. Contraceptive vaccines can provide most, if not all, the desired characteristics of an ideal contraceptive. This article reviews several factors involved in the establishment of pregnancy, focusing on those that are essential for successful implantation. Factors that are both essential and pregnancy-specific can provide potential targets for contraception. Using database search, 76 factors (cytokines/chemokines/growth factors/others) were identified that are involved in various steps of the establishment of pregnancy. Among these factors, three, namely chorionic gonadotropin (CG), leukemia inhibitory factor (LIF), and pre-implantation factor (PIF), are found to be unique and exciting molecules. Human CG is a well-known pregnancy-specific protein that has undergone phase I and phase II clinical trials, in women, as a contraceptive vaccine with encouraging results. LIF and PIF are pregnancy-specific and essential for successful implantation. These molecules are intriguing and may provide viable targets for immunocontraception. A multiepitope vaccine combining factors/antigens involved in various steps of the fertilization cascade and pregnancy establishment may provide a highly immunogenic and efficacious modality for contraception in humans.

Perinatal exposure to low-dose DE-71 increases serum thyroid hormones and gonadal osteopontin gene expression

Polybrominated diphenyl ethers (PBDEs) are flame retardants that have been widely used in manufacturing. They are major household and environmental contaminants that bioaccumulate. Humans are exposed primarily through dust inhalation and dietary ingestion of animal products. In animal studies, high doses of penta-brominated diphenyl ethers (penta-BDEs) in the mg/kg body weight (BW) range negatively impact brain development, behavior, memory, circulating thyroid hormone concentrations, the reproductive system and bone development. We investigated the effects of ingestion of a relatively low dose of the penta-BDE mixture DE-71 by pregnant and lactating rats on reproductive and thyroid parameters of the F1 offspring. F0 mothers received 60 μg/kg BW of DE-71 or vehicle daily by gavage from Day 1.5 of pregnancy through lactation (except the day of parturition). F1 pups were sacrificed at 21 d of age or outbred at approximately 80 d of age. Bred F1 females were sacrificed at Day 14.5 of pregnancy or at five months of age. Bred F1 males were sacrificed at five months of age. DE-71 treatment of the mothers affected the F1 females as evidenced by lower body weights at 80 d and five months of age, elevated serum T3 and T4 concentrations at Day 14.5 of pregnancy and increased thyroid gland weight and ovarian osteopontin mRNA at five months of age. Perinatal DE-71 exposure also increased testicular osteopontin mRNA in 21-day-old F1 males. Utilizing a granulosa cell in vitro model, we demonstrated that DE-71 activated the rat osteopontin gene promoter. Our results are the first to demonstrate that PBDEs increase rodent circulating T3 and T4 concentrations and gonadal osteopontin mRNA, and activate the osteopontin gene promoter. These changes may have clinical implications as others have shown associations between human exposure to PBDEs and subclinical hyperthyroidism, and overexpression of ovarian osteopontin has been associated with ovarian cancer.

Osteopontin: an effector and an effect of tumor metastasis

Osteopontin (OPN) is a matricellular protein that is produced by multiple tissues in our body and is most abundant in bone. It is also produced by cancer cells and plays a determinative role in the growth, progression and metastasis of cancer. Clinically, OPN has been reported to be upregulated in tumor cells per se; this is also reflected by increased levels of OPN in the circulation. Thus, increased OPN levels the plasma are an effect of tumor growth and progression. Functionally, high OPN levels are determinative of higher incidence of bone metastases in mouse models and are clinically correlated with metastatic bone disease and bone resorption in advanced breast cancer patients. Several research efforts have been made to therapeutically target and inhibit the activities of OPN. In this article we have reviewed OPN in its role as an effector of critical steps in tumor progression and metastasis, with a particular emphasis on its role in facilitating bone metastasis of breast cancer. We have also addressed the role of the host-derived OPN in influencing the malignant behavior of the tumor cells.

Local injury of the endometrium induces an inflammatory response that promotes successful implantation

OBJECTIVE

To study whether an injury-induced inflammation might be the mechanism underlying the favorable effect of endometrial biopsy on the implantation rate in in vitro fertilization (IVF) patients.

DESIGN

Controlled clinical study.

SETTING

A medical center IVF unit and a research institute.

PATIENT(S)

Women undergoing IVF who had previous failed treatment cycles.

INTERVENTION(S)

Endometrial samples were collected from two groups of patients on day 21 of their spontaneous menstrual cycle. The experimental, but not the control group underwent prior biopsy treatment on days 8 or/and 11 to 13 of that same cycle.

MAIN OUTCOME MEASURE(S)

Abundance of immune cells, cytokines/chemokines level, correlation between these parameters and pregnancy outcome.

RESULT(S)

A statistically significantly higher amount of macrophages/dendritic cells (HLA-DR+ CD11c+ cells) and elevated proinflammatory cytokines, tumor necrosis factor-α (TNF-α), growth-regulated oncogene-α (GRO-α), interleukin-15 (IL-15), and macrophage inflammatory protein 1B (MIP-1B), were detected in day-21 endometrial samples of the experimental group. A direct stimulatory effect of TNF-α on MIP-1B, GRO-α, and IL-15 messenger RNA (mRNA) expression was demonstrated. A positive correlation was found between the levels of macrophages/dendritic cells, MIP-1B expression, and TNF-α expression and the pregnancy outcome.

CONCLUSION(S)

A biopsy-induced inflammatory response may facilitate the preparation of the endometrium for implantation. Increased MIP-1B expression could possibly serve for prediction of implantation competence.

The role of hepatocyte nuclear factor-1beta in the pathogenesis of clear cell carcinoma of the ovary

PROBLEM

Clear cell carcinoma (CCC) of the ovary has a number of features distinguishing it from other epithelial ovarian carcinomas (EOC) because of its characteristic histology and biology, frequent concurrence with endometriotic lesion, and highly chemoresistant nature resulting in an extremely poor prognosis. The incidence of CCC has been steadily increasing in Japan. They comprise approximately 20% of all EOC. Understanding the mechanisms of CCC development and elucidating pathogenesis and pathophysiology are intrinsic to prevention and effective therapies for CCC.

METHOD OF STUDY

This article reviews the English language literature for biology, pathogenesis, and pathophysiological studies on endometriosis-associated EOC. Several data are discussed in the context of endometriosis and CCC biology.

RESULTS

Recent studies based on genome-wide expression analysis technology have noted specific expression of hepatocyte nuclear factor-1beta (HNF-1beta) in endometriosis and CCC, suggesting that early differentiation into the clear cell lineage takes place in the endometriosis. The HNF-1beta-dependent pathway of CCC will be discussed, which are providing new insights into regulation of apoptosis and glycogen synthesis and resistance of CCC to anticancer agents.

CONCLUSIONS

This review summarizes recent advances in the HNF-1beta and its target genes; the potential challenges to the understanding of carcinogenesis, pathogenesis, and pathophysiology of CCC; and a possible novel model is proposed.

Secreted phosphoprotein 1 (SPP1, osteopontin) binds to integrin alpha v beta 6 on porcine trophectoderm cells and integrin alpha v beta 3 on uterine luminal epithelial cells, and promotes trophectoderm cell adhesion and migration

Conceptus implantation involves pregnancy-specific alterations in extracellular matrix at the conceptus-maternal interface. Secreted phosphoprotein 1 (SPP1, osteopontin) is induced just before implantation and is present at the conceptus-maternal interface in mammals. In the present study, we investigated mechanisms by which SPP1 facilitates porcine conceptus and uterine luminal epithelial cell attachment. Native bovine milk and wild-type rat recombinant SPP1 stimulated trophectoderm cell migration. Bovine milk SPP1, ovine uterine SPP1, and recombinant wild-type, but not mutated, rat SPP1 promoted dose- and cation-dependent attachment of porcine trophectoderm and uterine luminal epithelial cells, which was markedly reduced in the presence of a linear Arg-Gly-Asp integrin-blocking peptide. Affinity chromatography and immunoprecipitation experiments revealed direct binding of alpha v beta 6 trophectoderm and alpha v beta 3 uterine epithelial cell integrins to SPP1. Immunofluorescence microscopy using SPP1-coated microspheres revealed colocalization of the alpha v integrin subunit and talin at focal adhesions as well as at the apical domain of trophectoderm cells. Similarly, immunofluorescence staining of implantation sites in frozen gravid uterine cross sections localized SPP1 and alpha v integrin to the apical surfaces of trophectoderm and luminal epithelium and beta 3 integrin to the apical surface of luminal epithelium. To our knowledge, the present study is the first to demonstrate functionally that SPP1 directly binds specific integrins to promote trophectoderm cell migration and attachment to luminal epithelium that may be critical to conceptus elongation and implantation.

Adhesion molecules in endometrial epithelium: tissue integrity and embryo implantation

Cell adhesion in endometrial epithelium is regulated to maintain the continuity and protectiveness of the luminal covering cell layer while permitting interstitial implantation of the embryo during a restricted period of about 4 days. Many apparently normal embryos fail to implant, and epithelial-embryo adhesion remains a poorly understood phenomenon. After menstruation, epithelial regeneration occurs by epiboly from the basal residues of glands, an activity that requires migration on extracellular matrix as well as cell-cell cohesion. Here we review current knowledge of adhesion molecules in the epithelium.

The Influence of Estrogen on Hepatobiliary Osteopontin (SPP1) Expression in a Female Rodent Model of Alcoholic Steatohepatitis

Our recent studies suggest that higher neutrophil infiltration in females correlates with increased hepatobiliary expression of osteopontin (OPN) in alcoholic steatohepatitis (ASH). The objective of this study was to understand the role of alcohol in altering estrogen levels in females by examining the effect of ethanol (EtOH) on the estrous cycle and then investigate the potential relationship between estradiol (E2) and hepatobiliary OPN expression in a female rat ASH model. Ovariectomized (OVX) and E2-implanted OVX rats in the ASH group were evaluated for OPN mRNA and protein expression. Low doses of E2 resulted in significant down-regulation of OPN protein and mRNA as compared to the OVX group. However, with increasing doses of E2, there was up-regulation of both OPN mRNA and protein. Osteopontin was localized primarily to the biliary epithelium. Liver injury assessed by serum ALT and histopathology revealed a pattern similar to OPN expression. In all groups, hepatic neutrophilic infiltration correlated positively with OPN expression. Based on these data, we conclude that in our ASH model, low doses of E2 appear to be hepatoprotective, whereas the protective effect appears to diminish with increasing doses of E2, although additional cause and effect studies are needed for confirmation.

Enhanced focal adhesion assembly reflects increased mechanosensation and mechanotransduction at maternal–conceptus interface and uterine wall during ovine pregnancy

The integrity of the fetal–maternal interface is critical for proper fetal nourishment during pregnancy. Integrins are important adhesion molecules present at the interface during implantation; however,in vivoevidence for integrin activation and focal adhesion formation at the maternal–conceptus interface is limited. We hypothesized that focal adhesion assembly in uterine luminal epithelium (LE) and conceptus trophectoderm (Tr) results from integrin binding of extracellular matrix (ECM) at this interface to provide increased tensile forces and signaling to coordinate utero-placental development. An ovine model of unilateral pregnancy was used to evaluate mechanotransduction events leading to focal adhesion assembly at the maternal–conceptus interface and within the uterine wall. Animals were hysterectomized on days 40, 80, or 120 of pregnancy, and uteri immunostained for integrins (ITGAV, ITGA4, ITGA5, ITGB1, ITGB3, and ITGB5), ECM proteins (SPP1, LGALS15, fibronectin (FN), and vitronectin (VTN)), cytoskeletal molecules (ACTN and TLN1), and a signal generator (PTK2). Focal adhesion assembly in myometrium and stroma was also studied to provide a frame of reference for mechanical stretch of the uterine wall. Large focal adhesions containing aggregates of ITGAV, ITGA4, ITGA5, ITGB1, ITGB5, ACTN, and PTK2 were detected in interplacentomal uterine LE and Tr of gravid but not non-gravid uterine horns and increased during pregnancy. SPP1 and LGALS15, but not FN or VTN, were present along LE and Tr interfaces in both uterine horns. These data support the idea that focal adhesion assembly at the maternal–conceptus interface reflects adaptation to increasing forces caused by the growing fetus. Cooperative binding of multiple integrins to SPP1 deposited at the maternal–conceptus interface forms an adhesive mosaic to maintain a tight connection between uterine and placental surfaces along regions of epitheliochorial placentation in sheep.

Progesterone and placentation increase secreted phosphoprotein one (SPP1 or osteopontin) in uterine glands and stroma for histotrophic and hematotrophic support of ovine pregnancy

Secreted phosphoprotein one (SPP1, osteopontin) may regulate conceptus implantation and placentation. We investigated effects of progesterone (P(4)) and the conceptus on expression and localization of SPP1 in the ovine uterus. Steady-state levels of SPP1 mRNA in the endometrium of unilaterally pregnant ewes did not differ significantly between nongravid and gravid horns within their respective days of pregnancy; however, levels did increase as pregnancy progressed. SPP1 mRNA was detectable in the glandular epithelium (GE) of both nongravid and gravid horns via in situ hybridization. SPP1 protein was localized to the apical surface of the luminal epithelium of both nongravid and gravid uterine horns. Gravid horns exhibited extensive stromal SPP1 on Days 40 through 120, whereas SPP1 was markedly lower in the stroma of nongravid uterine horns through Day 80 of pregnancy. By Day 120, stromal expression of SPP1 between nongravid and gravid horns was similar. Long-term P(4) treatment of ovariectomized ewes induced SPP1 in the uterine stroma and GE. A bioactive 45-kDa SPP1 fragment was purified from uterine secretions and promoted ovine trophectoderm cell attachment in vitro. Interestingly, increased stromal cell expression of SPP1 was positively associated with vascularization as assessed by von Willebrand factor staining. Finally, ovine uterine artery endothelial cells produced SPP1 during outgrowth into three-dimensional collagen matrices in an in vitro model system that recapitulates angiogenesis. Collectively, P(4) induces and the conceptus further stimulates SPP1 in uterine GE and stroma, where SPP1 likely influences histotrophic and hematotrophic support of conceptus development.

The conceptus increases secreted phosphoprotein 1 gene expression in the mouse uterus during the progression of decidualization mainly due to its effects on uterine natural killer cells

Within the mouse endometrium, secreted phosphoprotein 1 (SPP1) gene expression is mainly expressed in the luminal epithelium and some macrophages around the onset of implantation. However, during the progression of decidualization, it is expressed mainly in the mesometrial decidua. To date, the precise cell types responsible for the expression in the mesometrial decidua has not been absolutely identified. The goal of the present study was to assess the expression of SPP1 in uteri of pregnant mice (decidua) during the progression of decidualization and compared it with those undergoing artificially induced decidualization (deciduoma). Significantly (P<0.05) greater steady-state levels of SPP1 mRNA were seen in the decidua when compared with deciduoma. Further, in the decidua, the majority of the SPP1 protein was localized within a subpopulation of granulated uterine natural killer (uNK) cells but not co-localized to their granules. However, in addition to being localized to uNK cells, SPP1 protein was also detected in another cell type(s) that were not epidermal growth factor-like containing mucin-like hormone receptor-like sequence 1 protein-positive immune cells that are known to be present in the uterus at this time. Finally, decidual SPP1 expression dramatically decreased in uteri of interleukin-15-deficient mice that lack uNK cells. In conclusion, SPP1 expression is greater in the mouse decidua when compared with the deciduoma after the onset of implantation during the progression of decidualization. Finally, uNK cells were found to be the major source of SPP1 in the pregnant uterus during decidualization. SPP1 might play a key role in uNK killer cell functions in the uterus during decidualization.