Placental protein 14 functions as a direct T-cell inhibitor

The pregnancy-associated protein glycodelin as a potential sex-specific target for resistance to immunotherapy in non-small cell lung cancer

Lung cancer has been shown to be targetable by novel immunotherapies which reactivate the immune system and enable tumor cell killing. However, treatment failure and resistance to these therapies is common. Consideration of sex as a factor influencing therapy resistance is still rare. We hypothesize that the success of the treatment is impaired by the presence of the immunosuppressive pregnancy-associated glycoprotein glycodelin that is expressed in patients with non-small-cell lung cancer (NSCLC). We demonstrate that the glycan pattern of NSCLC-derived glycodelin detected by a lectin-based enrichment assay highly resembles amniotic fluid-derived glycodelin A, which is known to have immunosuppressive properties. NSCLC-derived glycodelin interacts with immune cells in vitro and regulates the expression of genes associated with inflammatory and tumor microenvironment pathways. In tumor microarray samples of patients, high glycodelin staining in tumor areas results in an impaired overall survival of female patients. Moreover, glycodelin colocalizes to tumor infiltrating CD8+ T cells and pro-tumorigenic M2 macrophages. High serum concentrations of glycodelin prior to immunotherapy are associated with a poor progression-free survival (p < 0.001) of female patients receiving PD-(L)1 inhibitors. In summary, our findings suggest that glycodelin not only is a promising immunological biomarker for early identification of female patients that do not benefit from the costly immunotherapy, but also represents a promising immunotherapeutic target in NSCLC to improve therapeutic options in lung cancer.

A cell abundance analysis based on efficient PAM clustering for a better understanding of the dynamics of endometrial remodelling

BACKGROUND

Single-cell RNA sequencing (scRNA-seq) is a powerful tool for investigating cell abundance changes during tissue regeneration and remodeling processes. Differential cell abundance supports the initial clustering of all cells; then, the number of cells per cluster and sample are evaluated, and the dependence of these counts concerning the phenotypic covariates of the samples is studied. Analysis heavily depends on the clustering method. Partitioning Around Medoids (PAM or k-medoids) represents a well-established clustering procedure that leverages the downstream interpretation of clusters by pinpointing real individuals in the dataset as cluster centers (medoids) without reducing dimensions. Of note, PAM suffers from high computational costs and memory requirements.

RESULTS

This paper proposes a method for differential abundance analysis using PAM as a clustering method and negative binomial regression as a statistical model to relate covariates to cluster/cell counts. We used this approach to study the differential cell abundance of human endometrial cell types throughout the natural secretory phase of the menstrual cycle. We developed a new R package -scellpam-, that incorporates an efficient parallel C++ implementation of PAM, and applied this package in this study. We compared the PAM-BS clustering method with other methods and evaluated both the computational aspects of its implementation and the quality of the classifications obtained using distinct published datasets with known subpopulations that demonstrate promising results.

CONCLUSIONS

The implementation of PAM-BS, included in the scellpam package, exhibits robust performance in terms of speed and memory usage compared to other related methods. PAM allowed quick and robust clustering of sets of cells with a size ranging from 70,000 to 300,000 cells. https://cran.r-project.org/web/packages/scellpam/index.html . Finally, our approach provides important new insights into the transient subpopulations associated with the fertile time frame when applied to the study of changes in the human endometrium during the secretory phase of the menstrual cycle.

The DNA damage response pathway regulates the expression of the immune checkpoint CD47

CD47 is a cell surface ligand expressed on all nucleated cells. It is a unique immune checkpoint protein acting as "don't eat me" signal to prevent phagocytosis and is constitutively overexpressed in many tumors. However, the underlying mechanism(s) for CD47 overexpression is not clear. Here, we show that irradiation (IR) as well as various other genotoxic agents induce elevated expression of CD47. This upregulation correlates with the extent of residual double-strand breaks (DSBs) as determined by γH2AX staining. Interestingly, cells lacking mre-11, a component of the MRE11-RAD50-NBS1 (MRN) complex that plays a central role in DSB repair, or cells treated with the mre-11 inhibitor, mirin, fail to elevate the expression of CD47 upon DNA damage. On the other hand, both p53 and NF-κB pathways or cell-cycle arrest do not play a role in CD47 upregualtion upon DNA damage. We further show that CD47 expression is upregulated in livers harvested from mice treated with the DNA-damage inducing agent Diethylnitrosamine (DEN) and in cisplatin-treated mesothelioma tumors. Hence, our results indicate that CD47 is upregulated following DNA damage in a mre-11-dependent manner. Chronic DNA damage response in cancer cells might contribute to constitutive elevated expression of CD47 and promote immune evasion.

Intratumoral Heterogeneity and Immune Modulation in Lung Adenocarcinoma in Female Smokers and Never Smokers

SIGNIFICANCE

Single-cell analysis of healthy lung tissue and lung cancer reveals distinct tumor cell populations, including cells with differential immune modulating capacity between smokers and never smokers, which could guide future therapeutic strategies.

Glycodelin regulates the numbers and function of peripheral natural killer cells

Natural killer (NK) cells comprise of ∼70% of the immune cell population in the maternal decidua and ∼15% of the mononuclear cells in the peripheral blood. The decidual NK cells capable of producing high levels of cytokines are functionally distinct from the peripheral NK cells that exhibit high cytotoxicity. The numbers of peripheral NK cells and their cytotoxicity potential have been correlated with pregnancy outcome. In the same context, glycodelin, an immunomodulatory protein, has been recognized to be essential for the establishment and maintenance of pregnancy, and its' reduced levels are associated with recurrent spontaneous abortions. We investigated the effect of glycodelin on the peripheral NK cells. Our results reveal that glycodelin suppresses the cytotoxicity of peripheral NK cells via downregulating perforin, granzyme B and IFNγ. Glycodelin also induces caspase-dependent death in only activated peripheral NK cells, the effect suggested to be mediated by glycodelin upon engaging with the CD7 cell surface receptor. Thus, during pregnancy, glycodelin modulates the function and the number of cytotoxic NK cells that pose a deleterious effect on the fetus, a semi-allograft. This study provides insights into the mechanism of the regulatory effect of glycodelin on NK cells and could possibly be exploited for the management of miscarriages.

Early Pregnancy Human Decidua is Enriched with Activated, Fully Differentiated and Pro-Inflammatory Gamma/Delta T Cells with Diverse TCR Repertoires

Pregnancy is a state where high and stage-dependent plasticity of the maternal immune system is necessary in order to equilibrate between immunosuppression of harmful responses towards the fetus and ability to fight infections. TCR γδ cells have been implicated in the responses in infectious diseases, in the regulation of immune responses, and in tissue homeostasis and repair. The variety of functions makes γδ T cells a particularly interesting population during pregnancy. In this study, we investigated the proportion, phenotype and TCR γ and δ repertoires of γδ T cells at the maternal–fetal interface and in the blood of pregnant women using FACS, immunohistochemistry and spectratyping. We found an enrichment of activated and terminally differentiated pro-inflammatory γδ T-cell effectors with specific location in the human decidua during early pregnancy, while no significant changes in their counterparts in the blood of pregnant women were observed. Our spectratyping data revealed polyclonal CDR3 repertoires of the δ1, δ2 and δ3 chains and γ2, γ3, γ4 and γ5 chains and oligoclonal and highly restricted CDR3γ9 repertoire of γδ T cells in the decidua and blood of pregnant women. Early pregnancy induces recruitment of differentiated pro-inflammatory γδ T-cell effectors with diverse TCR repertoires at the maternal–fetal interface.

The Roles of Glycodelin in Cancer Development and Progression

Glycodelin is a kind of glycoprotein expressed in secretory endometrium, pregnancy deciduas, and amniotic fluid originally, which is vital for the maintenance of normal human reproductive activities. Recent researches have reported that glycodelin is specifically expressed in various malignancies, including female-specific cancers such as endometrial cancer, ovarian cancer and breast cancer, and non-gender specific cancers including lung cancer, and colon cancer, and glycodelin expression correlates with the diagnosis and prognosis of cancer patients. This review focuses on the expression of glycodelin in different cancers and its role in cancer development and progression. Glycodelin possesses the abilities to regulate cancer cell proliferation, differentiation, and invasion, promote cancer angiogenesis, and modulate the differentiation and function of immune cells including T cells, dendritic cells, monocyte-macrophages, natural killer cells and B cells participating in cancer development. The expression of glycodelin can be regulated by stromal cells, lysophosphatidic acid, histone deacetylase inhibitors, and relaxin. In summary, glycodelin is a promising biomarker for the diagnosis and prognosis of cancer patients, and depending on its distinct immunoregulatory effects, glycodelin can be a prospective target for cancer immunotherapy.

Endometrial Stromal Decidualization Responds Reversibly to Hormone Stimulation and Withdrawal

Human endometrial stromal decidualization is required for embryo receptivity, angiogenesis, and placentation. Previous studies from our laboratories established that connexin (Cx)-43 critically regulates endometrial stromal cell (ESC) differentiation, whereas gap junction blockade prevents it. The current study evaluated the plasticity of ESC morphology and Cx43 expression, as well as other biochemical markers of cell differentiation, in response to decidualizing hormones. Primary human ESC cultures were exposed to 10 nM estradiol, 100 nM progesterone, and 0.5 mM cAMP for up to 14 days, followed by hormone withdrawal for 14 days, mimicking a biphasic ovulatory cycle. Reversible differentiation was documented by characteristic changes in cell shape. Cx43 was reversibly up- and down-regulated after the estradiol, progesterone, and cAMP treatment and withdrawal, respectively, paralleled by fluctuations in prolactin, vascular endothelial growth factor, IL-11, and glycodelin secretion. Markers of mesenchymal-epithelial transition (MET), and its counterpart epithelial-mesenchymal transition, followed reciprocal patterns corresponding to the morphological changes. Incubation in the presence of 18α-glycyrrhetinic acid, an inhibitor of gap junctions, partially reversed the expression of decidualization and MET markers. In the absence of hormones, Cx43 overexpression promoted increases in vascular endothelial growth factor and IL-11 secretion, up-regulated MET markers, and reduced N-cadherin, an epithelial-mesenchymal transition marker. The combined results support the hypothesis that Cx43-containing gap junctions and endocrine factors cooperate to regulate selected biomarkers of stromal decidualization and MET and suggest roles for both phenomena in endometrial preparation for embryonic receptivity.

Human malignant melanoma-derived progestagen-associated endometrial protein immunosuppresses T lymphocytes in vitro

Progestagen-associated endometrial protein (PAEP) is a glycoprotein of the lipocalin family that acts as a negative regulator of T cell receptor-mediated activation. However, the function of tumor-derived PAEP on the human immune system in the tumor microenvironment is unknown. PAEP is highly expressed in intermediate and thick primary melanomas (Breslow’s 2.5mm or greater) and metastatic melanomas, correlating with its expression in daughter cell lines established in vitro. The current study investigates the role of melanoma cell-secreted PAEP protein in regulating T cell function. Upon the enrichment of CD3⁺, CD4⁺ and CD8⁺ T cells from human peripheral blood mononuclear cells, each subset was then mixed with either melanoma-derived PAEP protein or PAEP-poor supernatant of gene-silenced tumor cells. IL-2 and IFN-γ secretion of CD4⁺ T cells significantly decreased with the addition of PAEP-rich supernatant. And the addition of PAEP-positive cell supernatant to activated lymphocytes significantly inhibited lymphocyte proliferation and cytotoxic T cell activity, while increasing lymphocyte apoptosis. Our result suggests that melanoma cell-secreted PAEP protein immunosuppresses the activation, proliferation and cytotoxicity of T lymphocytes, which might partially explain the mechanism of immune tolerance induced by melanoma cells within the tumor microenvironment.

The dimeric crystal structure of the human fertility lipocalin glycodelin reveals a protein scaffold for the presentation of complex glycans

Structural study of human glycodelin, which is involved in reproduction, reveals a homodimeric structure ideally suited as scaffold for the presentation of distinct glycans, whereas bioinformatic analysis indicated exclusive occurrence in suborders of primates that have a menstrual cycle.

Immunosuppressive Glycodelin A is an independent marker for poor prognosis in endometrial cancer

Background

Knowledge on immunosuppressive factors in the pathogenesis of endometrial cancer is scarce. The aim of this study was to assess Glycodelin (Gd) and its immunosuppressive isoform Glycodelin A (GdA) in endometrial cancer tissue and to analyze its impact on clinical and pathological features and patient outcome.

Methods

292 patients diagnosed and treated for endometrial cancer were included. Patient characteristics, histology and follow-up data were available. Gd and GdA was determined by immunohistochemistry and in situ hybridization was performed for Gd mRNA.

Results

Endometrial cancer shows intermediate (52.2%) or high (20.6%) expression for Gd in 72.8%, and GdA in 71.6% (intermediate 62.6%, high 9.0%) of all cases. The glycosylation dependent staining of GdA is tumour specific and correlates with the peptide-specific Gd staining though neither of the two is associated with estrogen receptor, progesterone receptor or clinic-pathological features. Also Gd protein positively correlates with Gd mRNA as quantified by in situ hybridization. Gd positive cases have a favourable prognosis (p = 0.039), while GdA positive patients have a poor outcome (p = 0.003). Cox-regression analysis proofed GdA to be an independent prognostic marker for patient survival (p = 0.002), besides tumour stage, grade and the concomitant diagnosis of hypertension.

Conclusion

Gd and GdA are commonly expressed in endometrial cancer tissue and seem to be of relevance in tumourigenesis. They differ not only in glycosylation but also in their biological activity, since only GdA holds prognostic significance for a poor overall survival in endometrial cancer patients. This finding might be explained by GdAs immunosuppressive capacity.

The role of placental protein 14 in the pathogenesis of endometriosis

Placental protein 14 (PP-14) is the principal secretory phase product of endometrium and has been shown to inhibit cell immune function. But its role in the pathogenesis of endometriosis is controversy. The objective of this study is to determine the concentrations of PP-14 in peritoneal fluid (PF) and serum and PP-14 protein expression in endometriotic lesions in women with ovarian endometriosis (n = 75) when compared to women without endometriosis (n = 49) between day 7 and day 20 of their menstrual cycle. Concentrations of PP-14 in PF and serum as well as PP-14 protein expression in endometriotic lesions in women with and without endometriosis were evaluated by using enzyme-linked immunosorbent assay and immunohistochemical staining, respectively. Serum PP-14 concentrations were significantly increased in women with endometriosis (7.5 ± 1.4 ng/mL) compared to those in women without endometriosis (5.8 ± 0.9 ng/mL; P < .05) and statistically decreased after surgery and further reduced by using gonadotropin-releasing hormone agonist therapy (P < .05). However, the concentrations of PP-14 in PF did not reach a significant difference between women with and without endometriosis (P > .05). In women with endometriosis, scores of PP-14 protein expression in the lesions (n = 50, 2.2 [0~5.8]) were significantly correlated with serum PP-14 concentrations (n = 50, 7.6 ± 1.3 ng/mL; P < .01). Our results suggest that PP-14 may play an important role in the pathogenesis of endometriosis.

The immunomodulating roles of glycoproteins in epithelial ovarian cancer

The complexity of the immune system demands an intricate defense mechanism by tumors. Ovarian and other tumors employ specific glycoproteins and the associated glycan sequences to modulate immune responses. Glycoproteins enable tumor cells that express or secrete these molecules to evade immune cell attack and induce the immune system to promote tumor growth. This review focuses first on the immune environment in ovarian cancer, and the mechanisms of activation and inhibition that immune cells undergo in order to either attack or ignore a target cell. Next we illustrate the immunomodulatory roles of ovarian cancer-associated glycans and glycoproteins in 1. preventing immune synapse formation, 2. serving as ligands of immune cell receptors, 3. scavenging cytokines and chemokines, and 4. participating in the formation of autoantibodies against the tumor. The importance of these immunomodulating strategies from the view points of understanding the tumor immunology of ovarian tumors, potential origin of such mechanisms, and specific strategies to circumvent the glycoconjugate-mediated suppression of immune responses is discussed in this review.

Endometrial secretions: creating a stimulatory microenvironment within the human early placenta and implications for the aetiopathogenesis of preeclampsia

Endometrial glands represent an important source of nutrients for the conceptus during the first trimester. Their secretions are enriched with carbohydrates, and glycogen accumulates within the syncytiotrophoblast of the placenta. It has been assumed that fetal and placental metabolism follow adult pathways, although it is now appreciated that early development occurs in a low-oxygen environment. In past decades, a novel family of putative insulin mediators, inositol phosphoglycans (IPGs), was discovered. These molecules act as allosteric activators and/or inhibitors of enzymes and transduction proteins involved in the control of cell signalling and metabolic pathways, and determine the specificity of responses after activation of the insulin receptor. One member, IPG P-type, activates pyruvate dehydrogenase phosphatase (PDH-Pase), glycogen synthase phosphatase, and glycerol-3-phosphate acyltransferase. Activation of key phosphatases play a major role in the regulation of glucose disposal by oxidative metabolism via PDH, and the non-oxidative storage by glycogen synthesis, both pathways classically known to be regulated by insulin. High concentrations of IPG P-type in amniotic fluid suggest a role in the regulation of carbohydrate metabolism in the fetal-placental unit. Glycogen accumulation in the syncytiotrophoblast also occurs in preeclamptic pregnancies, and is consistently associated with higher placental levels of IPG P-type. Here, we explore the relationship between nutrients provided by the endometrial glands during early pregnancy, IPG P-type and fetal metabolic requirements. We also discuss whether a disconnect between the placental/fetal metabolic state and oxygen tension could lead to a preeclamptic-type syndrome via leakage of Warburg/IPG mediators into the maternal circulation.

Characterization of the transcriptome of chorioamniotic membranes at the site of rupture in spontaneous labor at term

OBJECTIVE

The purpose of this study was to compare the transcriptome between the site of membrane rupture and the chorioamniotic membranes away from the site of rupture.

STUDY DESIGN

The transcriptome of amnion and chorion (n=20 each) from and distal to the site of rupture from women with spontaneous labor and vaginal delivery at term after spontaneous rupture of membranes was profiled with Illumina HumanHT-12 microarrays. Selected genes were validated with the use of quantitative reverse transcription-polymerase chain reaction.

RESULTS

Six hundred seventy-seven genes were differentially expressed in the chorion between the rupture and nonrupture sites (false discovery rate<0.1; fold change>1.5). Quantitative reverse transcription-polymerase chain reaction confirmed the differential expression in 10 of 14 genes. Enriched biological processes included anatomic structure development, cell adhesion and signal transduction. Extracellular matrix-receptor interaction was the most impacted signaling pathway.

CONCLUSION

The transcriptome of fetal membranes after spontaneous rupture of membranes in term labor is characterized by region- and tissue-specific differential expression of genes that are involved in signature pathways, which include extracellular matrix-receptor interactions.

Ovarian cancer-derived glycodelin impairs in vitro dendritic cell maturation

Local immunosuppressive mechanisms shape the tumor microenvironment and contribute to carcinogenesis. In ovarian cancer such mechanisms have been shown to influence survival. Dendritic cells (DCs) are central immunity regulators and induce potent cytotoxic T-cell responses as well as peripheral tolerance depending on modulatory stimuli. Here, we show that ovarian cancer-derived glycodelin (Gd), a glycoprotein that physiologically modulates local immunity in early pregnancy, induces a tolerogenic DC phenotype. Gd was isolated with high performance liquid chromatography from the malignant ascites of ovarian cancer patients. DCs were generated from monocytes of healthy donors and exposed to Gd with or without an inflammatory stimulus (tumor necrosis factor-alpha and interleukin 1-beta). We investigated the effect of Gd on DC surface marker expression, endopinocytotic activity, cytokine profile, and lymphoproliferative activity. DCs that were exposed to Gd altered their phenotype as seen by a differential expression of costimulatory molecules, whereas expression of DC-specific intercellular adhesion molecule 3-grabbing nonintegrin, a marker of an immature phenotype, was increased. Functional data provided further evidence for the immature/tolerogenic properties of Gd-pretreated DCs. Antigen uptake was retained, production of interleukin-10 was increased, and lymphoproliferative activity was reduced. This effect was reversible by adding Gd-blocking antibodies. Gd, which is found in the malignant ascites of ovarian cancer patients, induces a tolerogenic phenotype in DC, thereby shaping an immunodeficient tumor micromilieu.

Glycodelin A triggers T cell apoptosis through a novel calcium-independent galactose-binding lectin activity

Glycodelin A (GdA) is one of the progesterone inducible endometrial factors that protect the fetal semi-allograft from maternal immune rejection. The immunoregulatory effects of GdA are varied, with diverse effects on the fate and function of most immune cell types. Its effects on T cells are particularly relevant as it is capable of regulating T cell activation, differentiation, as well as apoptosis. We have previously reported that GdA triggers mitochondrial stress and apoptosis in activated T cells by a mechanism that is distinct and independent of its effects on T cell activation. In this study we describe the characterization of a cell surface receptor for GdA on T cells. Our results reveal a novel calcium-independent galactose-binding lectin activity of GdA, which is responsible for its apoptogenic function. This discovery adds GdA to a select group of soluble immunoregulatory lectins that operate within the feto-placental compartment, the only other members being the galectin family proteins. We also report for the first time that both CD4(+) and CD8(+) T cell subsets are equally susceptible to inhibition with GdA, mediated by its novel lectin activity. We demonstrate that GdA selectively recognizes complex-type N-linked glycans on T cell surface glycoproteins, and propose that the galectin-1 glycoprotein receptor CD7 maybe a novel target for GdA on T cells. This study, for the first time, links the lectin activity of GdA to its biological function.

Inflammation in reproductive disorders

Inflammatory disorders account for a significant percentage of gynecologic disease, particularly in reproductive age women. Inflammation is a basic method by which we respond to infection, irritation, or injury. Inflammation is now recognized as a type of nonspecific immune response, either acute or chronic. In gynecology, inflammation leads to anatomic disorders primarily as a result of infectious disease; however inflammation can affect ovulation and hormone production as well as be associated with endometriosis. Similarly, immune cell trafficking is an important component of cyclic endometrial development in each menstrual cycle. These immune cells are required for endometrial function, producing a vast array of inflammatory cytokines. Inflammation alters endometrial receptivity, however it may also play a role in tissue repair and remodeling. Finally, inflammation affects the trophoblast and trophoblast-endometrial interaction. Some components of the immune response are required for optimal fertility and normal tissue remodeling. A better understanding of the necessary role of inflammation in reproduction will allow more rational and targeted treatment of inflammatory disorders in reproductive medicine.

Increased expression of glycodelin mRNA and protein in rat lungs during ovalbumin-induced allergic airway inflammation

Asthma is a chronic inflammatory disease accompanied by airway obstruction and hyper-responsiveness. Asthmatic inflammation is characterized by the expression of multiple genes for inflammatory mediators. Glycodelin is a glycoprotein with several functions in cell recognition and differentiation. There is substantial evidence that glycodelin may be a mediator for immunomodulatory and immunosuppressive effects on several human tissues. To determine the potential role of glycodelin in the pulmonary immune response, we examined the distribution of the glycodelin mRNA and protein in an experimental rat model of allergen-induced airway inflammation. The experimental model developed an airway response to inhaled nebulized ovalbumin in adult rats. Two groups of rats (ovalbumin and saline) were challenged for 3 weeks, lungs were fixed and embedded, and sections were studied for expression of glycodelin mRNA by in situ hybridization and protein by immunohistochemistry. Glycodelin is expressed in Clara cells of bronchial epithelium, type II pneumocytes and alveolar macrophages. Densitometric analyses show a significant increase of the glycodelin mRNA and protein expression in rat lungs after ovalbumin challenge. Induced glycodelin amounts in tissue, particularly in Clara cells and alveolar macrophages were found. The altered expression pattern of glycodelin may contribute to the pulmonary immune response in asthmatic inflammation.

Glycodelin A, an immunomodulatory protein in the endometrium, inhibits proliferation and induces apoptosis in monocytic cells

Glycodelin A (GdA), is a lipocalin with an immunomodulatory role, secreted by the endometrium under progesterone regulation and proposed to play a role in protecting the fetus from maternal immune attack. Glycodelin A has an inhibitory effect on the proliferation of T cells and B cells and also on the activity of natural killer cells. We have earlier demonstrated that the inhibitory effect of glycodelin A on T cell proliferation is due to apoptosis induced in these cells through the caspase-dependent intrinsic mitochondrial pathway. Studies reported until now have shown that glycodelin modulates the adaptive immune responses. We, therefore, decided to look at its effect, if any, on the innate immune system. The effect of glycodelin on monocytes was studied using human monocytic cell lines, THP1 and U937, and primary human monocytes as model systems. We demonstrated that glycodelin inhibited the proliferation of THP1 and U937 and induced apoptosis in these cells as well as in primary monocytes. We found that this signaling was caspase-independent but followed the intrinsic mitochondrial pathway of apoptosis. No effect of glycodelin was seen on the phagocytic ability of monocytes post-differentiation into macrophages. These observations suggest that, at the fetomaternal interface, glycodelin plays a protective role by deleting the monocytes that could become pro-inflammatory. Importantly, leaving the macrophages untouched to carry on with efficient clearance of the apoptotic cells.

Immunohistochemistry, glycosylation and immunosuppression of glycodelin in human ovarian cancer

Glycodelins (Gds) are glycoproteins with a gender specific glycosylation. Glycodelin A (GdA) is primarily produced in endometrial and decidual tissue and secreted to amniotic fluid. Glycodelins were also identified in several cancer types, including serous ovarian cancer. Gds act as a T-cell inhibitor and are involved in inactivation of human monocytes. With a Gd peptide antibody, derived from a 15 amino acid sequence of human Gd and in situ hybridization experiments, the expression of Gd in serous, mucinous, endometrioid and clear cell ovarian tumors was identified. In contrast to former investigations with antibodies against GdA, a positive immunohistochemical reaction for Gd was observed in all forms of epithelium ovarian cancer. These results were confirmed with in situ hybridization. In addition, Gd is expressed in granulose cell tumors, a non-epithelial form of ovarian cancer. Furthermore, Gd was purified from ascites fluid of ovarian cancer patients. Ascites Gd showed significant differences in its structure of sialyl Lewis-type oligosaccharides compared to GdA. Additionally, ascites Gd inhibits IL-2 stimulated proliferation of peripheral blood leucocytes and inhibits adhesion of SLe(X)-positive cells to E-selectin. Therefore, Gd could act as an inhibitor of lymphocyte activation and/or adhesion in ovarian cancer.

Glycodelin protein and mRNA is downregulated in human first trimester abortion and partially upregulated in mole pregnancy

Glycodelin (Gd) is a major reproductive glycoprotein and a mediator for immunomodulatory effects directed to cellular, humoral, and innate immunity. Human pregnancy depends on a diversity of physiological processes including modulation of the maternal immunosystem. We evaluated the expression of Gd protein and mRNA in first trimester decidual tissue of normal pregnancies and spontaneous abortion and hydatidiform moles. Furthermore, in vitro experiments on endometrial cancer cells to analyze the effect of human chorionic gonadotropin (hCG) on Gd regulation were performed. In decidual tissue of abortion patients, Gd expression was significantly decreased compared with normal gestation, which was confirmed by in situ hybridization. In mole pregnancy, an upregulation of Gd in the first 8 weeks of pregnancy was present. Gd is a main product of decidual tissue in the first trimester of human pregnancy. Reduced Gd expression in abortive pregnancy could lead to an increased activation of the maternal immunosystem, thus causing rejection of the developing fetus. Moreover, Gd expression in endometrial cancer cells in vitro could be stimulated by addition of hCG. Therefore, we speculate that hCG could be one of the factors regulating Gd expression because hCG is downregulated in women with abortion and upregulated in mole pregnancy. In addition, we found a positive feedback loop in Gd and hCG expression in human pregnancy.

Human early placental development: potential roles of the endometrial glands

There is strong evidence that the endometrial glands play a key role in regulating placental development in many domestic species, but their contribution in the human has largely been ignored once implantation is complete. Here we re-evaluate their role during the first trimester. Connections between the glands and the intervillous space have been observed from day 17 post-conception through to the end of the first trimester. In the absence of a maternal arterial supply to the early placenta it is believed that the carbohydrate- and lipid-rich secretions represent an important source of nutrients during the first trimester, and possibly the beginning of the second trimester. The secretions also contain a variety of growth factors that may regulate placental morphogenesis since their receptors are present on villous and extravillous trophoblast, and villous endothelial cells. Other components of the secretions may modulate immune responses and trophoblast invasion at the materno-fetal interface. We speculate that lactogenic hormones secreted by decidual cells and the syncytiotrophoblast may act in concert with human chorionic gonadotropin to stimulate the secretory activity of glandular epithelial cells during the first trimester. There is circumstantial evidence, but as yet no conclusive proof, that deficient glandular activity is associated with pregnancy failure in the human.

Glycosylation related actions of glycodelin: gamete, cumulus cell, immune cell and clinical associations

Glycodelin is an example of a glycoprotein whose complex-type glycans mediate biological actions in human reproduction and immune reactions. Being attached to an identical protein backbone, glycodelin oligosaccharides vary significantly from one reproductive tissue to another and have an effect on its own secretion and role in cell communication. For instance, uterine glycodelin-A inhibits sperm-oocyte interaction by binding on the sperm head. This is a glycosylation-dependent phenomenon, in which fucosyltransferase-5 plays a key role. Glycodelin-S from seminal plasma binds evenly around the sperm head and maintains an uncapacitated state in the spermatozoa, until the isoform is detached during sperm passage through the cervix. Glycodelin-F from follicular fluid and Fallopian tube binds to the acrosomal region of the sperm head, thereby inhibiting both the sperm-oocyte binding and premature progesterone-induced acrosome reaction. The cumulus cells surrounding the oocyte can capture glycodelin-A and -F from the surrounding environment and convert these isoforms to a cumulus cell isoform, glycodelin-C. It differs by glycosylation from the other isoforms, and it too attaches on the sperm head, with the highest density in the equatorial region. Glycodelin-C is capable of detaching the sperm-bound inhibitory isoforms so that the sperm-oocyte binding is enhanced. Glycodelin-A also has immunosuppressive actions directed to cellular, humoral and innate immunity. Although these actions depend mainly on the protein backbone, glycosylation also plays a part. Glycosylated glycodelin may be involved in the protection of spermatozoa against maternal immune reactions, and glycodelin also has apoptogenic activity. Some glycosylation patterns of glycodelin may mask its apoptogenic domain. This review updates the recent research and clinical associations of glycodelin, highlighting the role of glycosylation.

Histone deacetylase inhibitors stimulate cell migration in human endometrial adenocarcinoma cells through up-regulation of glycodelin

Histone deacetylase inhibitors (HDACIs) have recently emerged as promising anticancer drugs to induce cell cycle arrest, cytodifferentiation, and apoptosis. It is suggested, however, that HDACIs promote cell migration and invasion depending on the cell type. We have reported previously that treatment with HDACIs, including trichostatin A and suberoylanilide hydroxamic acid (SAHA) or progesterone in combination with estrogen, can induce cytodifferentiation of endometrial adenocarcinoma Ishikawa cells through up-regulation of glycodelin, a progesterone-induced endometrial glycoprotein. Given the reported role of glycodelin in cell motility and the migration-modulating potential of HDACIs, we investigated using wound healing assay and transwell migration assay whether ovarian steroid hormones, trichostatin A, or SAHA affects cell migration in endometrial cancer cell lines, Ishikawa and RL95-2. Treatment with ovarian steroid hormones, trichostatin A, and SAHA enhanced cell migration together with up-regulation of glycodelin. SAHA-augmented cell migration was almost completely blocked by gene silencing of glycodelin. Furthermore, overexpression of gycodelin alone resulted in increased cell motility in Ishikawa cells. Our results collectively indicate that glycodelin positively regulates cell motility acting as a mediator of HDACI-enhanced endometrial cell migration, suggesting the involvement of glycodelin in the dynamic endometrial gland morphogenesis during menstrual cycle. Our results raise a possibility that the use of HDACIs in the therapy for glycodelin-inducible endometrial and presumably other gynecological cancers may enhance invasion in cases in which the HDACIs fail to exert differentiation-inducing and/or antiproliferative effects.

Roles of glycodelin in modulating sperm function

Glycodelin is a glycoprotein with three well-defined isoforms. They are named as glycodelin-S, glycodelin-A and glycodelin-F. The three isoforms have similar protein core but different carbohydrate moieties. Glycodelin-S is abundant in the human seminal plasma. It suppresses sperm capacitation and in doing so, it maintains the spermatozoa in an uncapacitated state before they enter into the uterine cavity. Glycodelin-A is abundant in the amniotic fluid. It is also secreted from endometrial glands into uterine fluid and is produced by the fallopian tube. Glycodelin-A is the first endogenous glycoprotein that was found to inhibit the binding of spermatozoa to the zona pellucida. The immunosuppressive properties of glycodelin-A suggest that the molecule may protect the spermatozoa from immune attack in the maternal reproductive tract. Glycodelin-F was first found in the follicular fluid, hence its name. It also inhibits spermatozoa-zona pellucida binding. In addition, glycodelin-F suppresses progesterone-induced acrosome reaction, and may serve to prevent premature acrosome reaction. Preliminary findings suggest possible presence of yet another glycodelin isoform in the extracellular matrix of cumulus oophorus. Unlike glycodelin-A and -F, it stimulates spermatozoa-zona pellucida binding. In summary, different isoforms of glycodelin have different biological roles on sperm function, and they act in succession to contribute to the success of fertilization.

Meet the multifunctional and sexy glycoforms of glycodelin

Glycodelin, a human-secreted glycoprotein that appears in a small number of glycoforms, exhibits diverse biological activities, such as in contraception and immunosuppression. Moreover, different tissue-specific glycoforms appear to mediate diverse functions. Quite unusually, the glycodelin N-linked glycans differ between the male and female glycoforms. The fact that these glycans are fundamental for exerting the physiological activities of the different glycoforms, makes them an interesting target for glycobiology research. This review will focus on the involvement of the glycans in glycodelin activity and compare between the several glycoforms.

alpha2,6-Sialylation promotes binding of placental protein 14 via its Ca2+-dependent lectin activity: insights into differential effects on CD45RO and CD45RA T cells

Placental protein 14 (PP14; glycodelin) is a pregnancy-associated immunoregulatory protein that is known to inhibit T cells via T-cell receptor desensitization. The recent demonstration of PP14 as lectin has provided insight into how it may mediate its CD45 glycoprotein-dependent T-cell inhibition. In this study, we have investigated PP14's lectin-binding properties in detail. Significantly, PP14 reacts with N-acetyllactosamine (LacNAc) as was also found for members of the galectin family, such as the potent immunoregulatory protein, galectin-1. However, in contrast to galectin-1, PP14's binding is significantly enhanced by alpha2,6-sialylation and also by the presence of cations. This was demonstrated by preferential binding to fetuin as compared with its desialylated variant asialofetuin (ASF) and by using free alpha2,6- versus alpha2,3-sialylated forms of LacNAc in competitive inhibition and direct solid-phase binding assays. Interestingly, from immunological point of view, PP14 also binds differentially to CD45 isoforms known to differ in their degree of sialylation. PP14 preferentially inhibits CD45RA+, as compared with CD45RO+ T cells, and preferentially co-capped this variant CD45 on the T-cell surface. Finally, we demonstrate that PP14 promotes CD45 dimerization and clustering, a phenomenon that may regulate CD45 activity.

Stimulation of hCG protein and mRNA in first trimester villous cytotrophoblast cells in vitro by glycodelin A

AIM

Human chorionic gonadotropin (hCG) is produced by fetal trophoblast cells and secreted into maternal circulation mainly in the first trimester of pregnancy. Another glycoprotein, glycodelin A, is one of the main products of the maternal decidua during this period. The purpose of this study was to investigate the effect of glycodelin A on hCG release by isolated cytotrophoblast cells in vitro.

METHODS

Cytotrophoblast cells were prepared from human first trimester placenta and incubated with varying concentrations of glycodelin A. Supernatants were assayed for hCG protein concentrations, and quantification of beta hCG mRNA was carried out by RT-PCR. Expression of hCG was analysed in stimulated trophoblast cells and in unstimulated controls by immunocytochemistry.

RESULTS

Glycodelin A induces a dose-dependent increase of hCG production. An increase of hCG expression was measured at 100 and 200 microg/mL glycodelin-A treatment in trophoblast cell culture by TaqMan assay on mRNA level. We found a moderate staining of hCG in control trophoblast cells, whereas a strong hCG staining was seen in glycodelin A-treated trophoblast cells.

CONCLUSIONS

HCG is a marker for the differentiation process of trophoblast cells. Our results suggest that glycodelin A secreted by the decidualized endometrium is involved in the regulation of hormones produced by the trophoblast.

Glycodelin-S in Human Seminal Plasma Reduces Cholesterol Efflux andInhibits Capacitation ofSpermatozoa

Tight control of sperm capacitation is important for successful fertilization. Glycodelin-S is one of the most abundant glycoproteins in the human seminal plasma. However, its function is unclear. We investigated the role of glycodelin-S on capacitation of human spermatozoa. Binding kinetics experiments demonstrated the presence of two saturable and reversible binding sites of glycodelin-S on human spermatozoa. Differently glycosylated other isoforms of glycodelin, glycodelin-A and -F, did not compete with glycodelin-S for these binding sites, suggesting that the glycodelin-S binding sites are different from those of the other isoforms. Indirect immunofluorescent staining revealed specific binding of glycodelin-S around the sperm head. This immunoreactivity was greatly reduced in spermatozoa that had migrated through the cervical mucus surrogates. Glycodelin-S at physiological concentrations significantly reduced the bovine serum albumin and cyclodextrin-induced cholesterol efflux and down-regulated the adenylyl cyclase/protein kinase A/tyrosine kinase signaling pathway, resulting in suppression of capacitation. Deglycosylation abolished glycodelin-S binding and the effect of glycodelin-S on bovine serum albumin-induced capacitation. This indicates that the carbohydrate moiety of glycodelin-S is critical for the function of the molecule. It is concluded that glycodelin-S in seminal plasma maintains the uncapacitated state of human spermatozoa.

Expression of glycodelin A in decidual tissue of preeclamptic, HELLP and intrauterine growth-restricted pregnancies

During pregnancy, the placenta produces a variety of proteins that are responsible for the establishment of the foeto-maternal tolerance and circulation. The aim of this study was to investigate the expression of glycodelin A (formerly named PP14) in decidual tissue of placentas with intrauterine growth restriction (IUGR), preeclamptic patients, hemolysis, elevated liver, low-platelet (HELLP) patients and normal decidual tissue. Slides of paraffin-embedded decidual tissue of patients with IUGR, preeclamptic patients, HELLP patients and normal-term placentas were incubated with either polyclonal or monoclonal antibodies against glycodelin A. Staining reaction was performed with the ABC reagent. Intensity of immunohistochemical reaction on the slides was analysed using a semi-quantitative score. In addition, expression of glycodelin mRNA was analysed by in situ hybridisation. Expression of glycodelin A was significantly reduced in decidual cells of placentas with IUGR and HELLP, as investigated with both monoclonal and polyclonal antibodies and in situ hybridisation. However, preeclamptic decidual tissue showed no significantly different expression of intensity of glycodelin mRNA compared with normal placental tissue controls. A reduced expression of glycodelin A by decidual cells seems to be related to IUGR and HELLP. Therefore, glycodelin A might play an important role in the pathogeneses of these diseases.

Pregnancy zone protein is a carrier and modulator of placental protein-14 in T-cell growth and cytokine production

A successful pregnancy can only occur when the maternal immune system fails to attack the allogeneic fetus. Two plasma proteins with described immunoregulatory activities, pregnancy zone protein (PZP) and placental protein-14 (PP14; also known as glycodelin-A), increase dramatically during pregnancy, prompting us to examine their potential role in mediating fetal protection. First, we demonstrated that both native PZP and its receptor-recognized monoamine-activated form (MA-PZP) bound non-covalently and specifically to PP14, exhibiting K(d) values greater than 3 microM, as determined by surface plasmon resonance. Our evidence further suggests that PZP is potentially a more effective carrier of PP14 than its relative alpha2-macroglobulin. Second, we found that T-cell activation, as measured by increased proliferation and IL-2 production, was inhibited by either PZP or PP14 in a dose-dependent manner. However, when PZP and PP14 were combined, they acted synergistically to inhibit T cell proliferation and IL-2 production. Interestingly, the combination of PZP and PP14 had little effect on the production of T(H)2 cytokine, IL-4. Based upon these findings, we hypothesize that PZP and PP14 form a stable complex in the plasma of pregnant women and together act synergistically to selectively modulate T-cell activation. Mechanistically, this activity appears to be independent of the PZP receptor (CD91) or PZP's anti-proteinase activity.

Differential Regulation of Th1/Th2 Cytokine Responses by Placental Protein 14

The potency of TCR signaling during primary CD4+ T cell activation influences initial cytokine expression patterns and subsequent polarization toward either Th1 or Th2 subsets. In this study, we demonstrate that the T cell inhibitor placental protein 14 (PP14; glycodelin) preferentially inhibits Th1 cytokine responses and chemokine expression when present during ex vivo priming of CD4+ T cells. PP14 synergizes with exogenously added IL-4 in skewing T cell responses. Significantly, PP14 impairs the down-regulation of GATA-3 transcriptional regulator expression that normally accompanies T cell activation, which is a prerequisite for Th1 development. Taken together, these data document for the first time the ability of PP14 to skew Th responses.

Advances in uterine protein research: reproduction and cancer

Uterine protein research has advanced from the measurements of specific compounds to detailed analysis of the genes that regulate protein synthesis and build up the complex carbohydrate structures that play important functional roles. Some 80% of all human proteins are glycoproteins. Functional glycomics highlights the importance of glycosylation in glycoprotein function. Glycodelin is a representative example of functional glycomics because its various glycoforms have different functions. In the uterus, synthesis of glycodelin-A is temporally regulated by progesterone. During the estrogen-dominated fertile window, absence of glycodelin synthesis is significant because uterine glycodelin-A potently and dose-dependently inhibits sperm-egg binding, the initial step in fertilization. The anti-fertilization propensity of glycodelin-A during the luteal phase of the cycle is highly glycosylation-dependent, and there is an intricate functional interplay between spermatozoa, zona pellucida and the various glycodelin isoforms present in the uterine fluid, seminal plasma and follicular fluid, respectively. Endometrial glycodelin synthesis can be induced during the fertile window by administration of progestagens, such as in levonorgestrel hormone-releasing IUD and contraceptive implants. Glycodelin can be chemically modified in such a fashion that it blocks the binding site on CD4 for the HIV surface glycoprotein, synthesis of viral gp 120, and infection of peripheral blood mononuclear cells by the primary HIV isolate THA/93/051, thus potentially inhibiting HIV transmission. Now that a cell line producing the contraceptive isoform has been identified by recombinant technology, these findings may have application for locally applied antiviral contraception. Glycodelin also has immunosuppressive properties, suggesting that the recognition mechanisms in immune and reproductive systems may have converged. Given its inhibitory activity on natural killer cells, abundant at the fetomaternal interphase, the high glycodelin concentration at the same site suggests a role in fetomaternal defense mechanisms. This may be relevant in women with recurrent miscarriage, in whom both the serum and uterine fluid glycodelin concentrations are decreased. Experiments on cancer cell lines have demonstrated increased epithelial differentiation by glycodelin cDNA transfection, and also by co-culture of cancer cells with normal stromal cells in the presence of basement membrane components. Both approaches result in glycodelin expression concomitant with decreased cell proliferation and reversion of the malignant phenotype. These results suggest an active role of normal stromal cells, basement membrane components and glycodelin in epithelial differentiation and glandular morphogenesis. This disposition of glycodelin is significant in patients with certain carcinomas, in which glycodelin-expressing tumors carry better prognosis than glycodelin-negative tumors of the same clinical stage and histological grade. Research on functional glycomics continues to produce significant information on fundamental aspects of fertilization, implantation, pregnancy and cancer.

Gastric transcription profile of Helicobacter pylori infection in the rhesus macaque

Infection with Helicobacter pylori is usually asymptomatic but sometimes progresses to peptic ulcer disease or gastric adenocarcinoma. The development of disease involves both host and bacterial factors. In order to better understand host factors in pathogenesis, we studied the gastric transcription profile of H. pylori infection in the rhesus macaque by using DNA microarrays. Significant changes were found in the expression of genes important for innate immunity, chemokines and cytokines, cell growth and differentiation, apoptosis, structural proteins, and signal transduction and transcription factors. This broad transcription profile demonstrated expected up-regulation of cell structural elements and the host inflammatory and immune response, as well as the novel finding of down-regulation of heat shock proteins. These results provide a unique view of acute H. pylori infection in a relevant animal model system and will direct future studies regarding the host response to H. pylori infection.

Endometrial glands as a source of nutrients, growth factors and cytokines during the first trimester of human pregnancy: a morphological and immunohistochemical study

BACKGROUND

The maternal circulation to the human placenta is not fully established until 10-12 weeks of pregnancy. During the first trimester the intervillous space is filled by a clear fluid, in part derived from secretions from the endometrial glands via openings in the basal plate. The aim was to determine the activity of the glands throughout the first trimester, and to identify components of the secretions.

METHODS

Samples of human decidua basalis from 5-14 weeks gestational age were examined by transmission electron microscopy and immunohistochemically. An archival collection of placenta-in-situ samples was also reviewed.

RESULTS

The thickness of the endometrium beneath the implantation site reduced from approximately 5 mm at 6 weeks to 1 mm at 14 weeks of gestation. The glandular epithelium also transformed from tall columnar cells, packed with secretory organelles, to a low cuboidal layer over this period. The lumens of the glands were always filled with precipitated secretions, and communications with the intervillous space could be traced until at least 10 weeks. The glandular epithelium reacted strongly for leukaemia inhibitory factor, vascular endothelial growth factor, epidermal growth factor, transforming growth factor beta, alpha tocopherol transfer protein, MUC-1 and glycodelin, and weakly for lactoferrin. As gestation advanced uterine natural killer cells became closely approximated to the basal surface of the epithelium. These cells were also immunopositive for epidermal growth factor.

CONCLUSIONS

Morphologically the endometrial glands are best developed and most active during early human pregnancy. The glands gradually regress over the first trimester, but still communicate with the intervillous space until at least 10 weeks. Hence, they could provide an important source of nutrients, growth factors and cytokines for the feto-placental unit. The endometrium may therefore play a greater role in regulating placental growth and differentiation post-implantation than previously appreciated.

Negative regulation of T cell activation by placental protein 14 is mediated by the tyrosine phosphatase receptor CD45

CD45 is the major protein tyrosine phosphatase receptor on T cell surfaces that functions as both a positive and a negative regulator of T cell receptor (TCR) signaling. Although CD45 is required for the activation of TCR-associated Src family kinases, it also dephosphorylates phosphoproteins involved in the TCR-signaling cascade. This study links CD45 to the inhibitory activity of placental protein 14 (PP14), a major soluble protein of pregnancy that is now known to be a direct modulator of T cells and to function by desensitizing TCR signaling. PP14 and CD45 co-capped with each other, pointing to a physical linkage between the two. Interestingly, however, the binding of PP14 to T cell surfaces was not restricted to CD45 alone, with evidence showing that PP14 binds to other surface molecules in a carbohydrate-dependent fashion. Notwithstanding the broader molecular binding potential of PP14, its interaction with CD45 appeared to have special functional significance. Using transfected derivatives of the HPB. ALL mutant T cell line that differ in CD45 expression, we established that the inhibitory effects of PP14 are dependent upon the expression of intact CD45 on T cell surfaces. Based upon these findings, we propose a new immunoregulatory model for PP14, wherein one of its surface molecular targets, CD45, mediates its T cell inhibitory activity, accounting for the intriguing capacity of PP14 to elevate TCR activation thresholds and thereby down-regulate T cell activation.

Placental protein 14 regulates selective B cell responses

Placental protein 14 (PP14) is a glycoprotein of the lipocalin family that acts as a negative regulator in T cell receptor-mediated activation. In this study, we investigated PP14s potential role in regulating B cell activation. While PP14-inhibited B cell proliferation, IgM secretion and the surface expression of MHC class II, the expression of other surface molecules, such as CD69 and CD86, were unaffected. These observed effects were independent of the anti-IgM concentration used for stimulation, regardless of the presence of either T cells or IL-4, and persisted when B cells were stimulated by stimuli, which circumvent early events during B cell Ag receptor (BCR) activation, namely, protein kinase C activators in combination with Ca(2+) ionophore. Interestingly, we demonstrated that PP14s inhibitory characteristics are reminiscence of that achieved by independent ligation of CD19 using anti-CD19 mAb. Together with our previously reported effects on T cells, these findings identify PP14 as a soluble regulatory factor capable of interacting with both T and B cells in a carbohydrate-dependent manner and as a result it can affect both cellular and humoral immune responses.

Glycodelin: a major lipocalin protein of the reproductive axis with diverse actions in cell recognition and differentiation

Glycodelin is a glycoprotein that belongs to the lipocalin superfamily. Depending on glycosylation, glycodelin appears in various isoforms. In the uterus, glycodelin-A is the major progesterone-regulated glycoprotein secreted into uterine luminal cavity by secretory/decidualized endometrial glands. The other tissues expressing glycodelin include fallopian tubes, ovary, breast, seminal vesicle, bone marrow, and eccrine glands. Glycodelin-A potently and dose-dependently inhibits human sperm-egg binding, whereas differently glycosylated glycodelin-S from seminal plasma has no such effect. Absence of contraceptive glycodelin-A in the uterus during periovulatory midcycle is consistent with an open "fertile window." Glycodelin induced by local or systemic administration of progestogens may potentially reduce the fertilizing capacity of sperm in any phase of the menstrual cycle. Glycodelin also has immunosuppressive activity. Its high concentration at the fetomaternal interface may contribute to protection of the embryonic semiallograft. Besides being an epithelial differentiation marker, glycodelin appears to play a role in glandular morphogenesis, as transfection of glycodelin cDNA into a glycodelin-negative breast cancer cells resulted in formation of gland-like structures, restricted proliferation, and induction of other epithelial markers. These various properties, as well as the chemistry, biology, and clinical aspects of glycodelin, continue to be areas of active investigation reviewed in this communication.

Serial triggering of T cell receptors results in incremental accumulation of signaling intermediates

Triggering of the T cell receptor (TCR) leads to the production of intracellular intermediates with half-life of a few minutes. Signaling kinetics of events originating from serial TCR triggering and its relation to antigen dose was investigated. In this study we documented incremental accumulation of short-lived intermediates of the extracellular signal-regulated kinase (ERK) family, produced during successive TCR triggering. The rate and extent of the intermediate accumulation are essentially determined by the level of TCR engagement and are augmented by costimulation. ERK-1 and ERK-2 exhibit different rates of accumulation following serial receptor triggering. The data indicate that the quantitative kinetic differences in downstream signaling pathways induce qualitatively distinct biological outcomes. Although CD69, interleukin-2, and interferon-gamma (IFN-gamma) were primarily produced by high antigen doses that supported high MAPK phosphorylation, maximal interleukin-5 expression is induced by low and intermediate stimulus doses that do not support significant accumulation of activated ERK. We further demonstrated that the rate of phosphorylated ERK accumulation correlates with the duration of delay between T cell stimulation and the onset of IFN-gamma response, with stronger stimuli giving a more rapid IFN-gamma response. This delay might reflect the time required for the accumulation of signaling intermediates up to a threshold level that is necessary for activation. Thus, the data suggest that signaling events originating from serially triggered TCR are not simply sustained but are gradually accumulated and are integrated in a corresponding response.