Human amniotic fluid glycoproteins expressing sialyl Lewis carbohydrate antigens stimulate progesterone production in human trophoblasts in vitro

Glycodelin in reproduction

To achieve a successful pregnancy in humans, sperm is required for capacitation, followed by binding to and entry into an oocyte. Maternal endometrial epithelial cells (EECs) prepare the appropriate implantation environment through regulation of immune cells and endometrial cells. After acquiring endometrial receptivity, a successful pregnancy consists of complex and finely regulated steps involving apposition, adhesion, invasion, and penetration. Glycodelin is a secretory glycoprotein that affects cell proliferation, differentiation, adhesion, and motility. Glycodelin has four glycoforms (glycodelin-A, -S, -F. and -C); differences in glycosylation affect each characteristic function. Glycodelin has a unique temporospatial pattern of expression, primarily in the reproductive tract where glycodelin is mid-secretory phase-dominant. Recent studies have demonstrated that glycodelin protein has the potential to regulate various processes, including immunosuppression, fertilization, and implantation. This review details the orchestrated regulation of successful pregnancy by glycodelin as well as a discussion of the basic characteristics of glycodelin.

The expression of fucose isoforms of amniotic and plasma alpha-1-acid glycoprotein derived from 2nd and 3rd trimester normal pregnancies

OBJECTIVES

To analyse modifications in AGP fucosylation in relation to different stages of human pregnancy.

DESIGN AND METHODS

The relative amounts of three fucosyl-glycotopes on AGP were analysed by lectin-ELISA using fucose-specific biotinylated lectins in 169 plasma and 178 amniotic fluid samples from normal pregnancies with gestational ages of 14 to 42 weeks.

RESULTS

The plasma AGPs of all the pregnant women and amniotic AGPs from the 2nd trimester lacked fucoses. In contrast, in the 3rd trimester the amniotic AGPs were highly decorated by the innermost alpha1,6-fucose as well as alpha1,2- and alpha1,3-fucoses of the outer arms, reaching the highest expression around the perinatal period. At delivery the relative amounts of the alpha1,3- and alpha1,2-AGP isoforms, but not the alpha1,6 isoform, significantly decreased.

CONCLUSIONS

The highly fucosylated amniotic AGP isoforms could be implicated in regulatory processes to ensure homeostasis during pregnancy and to protect the fetus. They have the potential of becoming laboratory markers in obstetrics to monitor pregnancy.

Effects of phytoestrogens genistein and daidzein on progesterone and estrogen (estradiol) production of human term trophoblast cells in vitro

OBJECTIVE

Phytoestrogens are a diverse group of nonsteroidal plant compounds that occur naturally in many plants. Because they possess a ring system similar to estrogens they are able to bind on estrogen receptors alpha and beta in humans. The effects of the phytoestrogens genistein and daidzein on the production of progesterone and estrogen in isolated human term trophoblast cells in vitro were tested in this study.

MATERIAL AND METHODS

Cytotrophoblast cells were isolated from human term placentas. Phytoestrogens genistein and daidzein were incubated in different concentrations with trophoblast cells. Untreated cells were used as controls. After 24 h aliquots were removed and tested for progesterone and estrogen production.

RESULTS

The production of the steroid hormones progesterone and estrogen are influenced by phytoestrogens genistein and daidzein in human term trophoblast cells. A strong inhibition effect of both phytoestrogens tested in the production of progesterone was demonstrated. In addition, a significant stimulating effect on estrogen production by genistein and daidzein was observed.

CONCLUSION

Results obtained with this study show that phytoestrogens (genistein and daidzein) sufficiently reduce progesterone production in human term trophoblast cells. Because blockade of progesterone is a possible mechanism involved in initiation of labor, we may speculate that high doses of phytoestrogens at the feto-maternal interphase could play a negative role in maintenance of pregnancy. Stimulation of estrogen production by genistein and daidzein in trophoblast cells is probably due to estrogen receptor blocking effects of both phytoestrogens. Trophoblast cells seem to compensate blocking of its estrogen receptors by higher estrogen production.

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.

The immunomodulatory glycan LNFPIII initiates alternative activation of murine macrophages in vivo

The early pathogen-macrophage interactions that help drive macrophage maturation towards classically or alternatively activated are largely unknown. To examine this question we utilized the immunomodulatory glycan Lacto-N-fucopentaose III (LNFPIII), which contains the Lewis X (LeX) trisaccharide, to activate murine peritoneal macrophages in vivo. Because LNFPIII is known to induce anti-inflammatory responses, we asked if LNFPIII stimulation of macrophages in vivo initiates alternative activation events such as upregulation of Arginase 1, Ym1, FIZZ-1, MGL-1 or macrophage mannose receptor (MMR). Examination of peritoneal exudate cells from mice 20 hr post-LNFPIII injection demonstrated increased Arginase 1 activity, at the mRNA and protein levels, coincident with undetectable inducible nitric oxide synthase expression or nitric oxide production. In addition to Arginase 1, Ym1 expression was also significantly upregulated at 20 and 48 hr after LNFPIII exposure in vivo. However, the expression of FIZZ-1, MGL-1, and MMR was not changed in these macrophages. In an attempt to determine activation requirements for functional activity, we adoptively transferred antigen-pulsed, in vivo LNFPIII activated macrophages into naïve recipients and found that they were capable of triggering recipient T cells to secrete elevated levels of interleukin (IL)-10 and IL-13 compared to mice receiving control macrophages. Together, these data demonstrate that upregulation of expression of Arginase 1 and Ym1 occur very early in activation of macrophages, and can be independent of other alternatively activated (AA) macrophage markers. Importantly, these early events appear to be IL-4/IL-13-independent in our model. In the future we hope to determine if upregulation of these initial AA maturational events is sufficient for these macrophages to exert immunoregulatory activity in vivo.

Histochemistry for Placenta Research: Theory and Application

Histochemical techniques have contributed significantly to advances in placental biology and cell biology. In this mini-review, we describe recent advances in histochemical technologies and show how these technologies can profoundly improve our understanding of placenta morphological function related to health and disease. Fundamental theories and applications of five separate methods discussed here are 1) tissue-based polymerase chain reaction by laser microdissection, 2) a novel antigen retrieval method using citraconic anhydride plus heating, 3) immunohistochemical detection of Lewis-related antigen expression and galectin-1 binding in the human placenta, 4) confocal microscopy analysis of IgG transport in placental trophoblasts, and 5) high-resolution immunofluorescence and correlative microscopy using ultrathin cryosections in placental research. This review article is based on a presentation given in a workshop entitled Histochemistry: Theory and Application at the 12th International Federation of Placenta Associations Meeting held in Kobe, Japan, on September 9, 2006.

Regulation of progesterone production in human term trophoblasts in vitro by CRH, ACTH and cortisol (prednisolone)

BACKGROUND

In most mammals, onset of labor is accompanied with progesterone withdrawal. In humans, cortisol blockade of progesterone is a possible mechanism involved in the initiation of labor. Therefore, aim of the study was to clarify the effect of CRH, ACTH and cortisol (prednisolone) on the release of progesterone by term trophoblast cells in vitro.

METHODS

Cytotrophoblast cells were prepared from human term placentas by standard dispersion of villous tissue followed by a percoll gradient centrifugation step. Trophoblasts were incubated with CRH, ACTH as well as with prednisolone.

RESULTS

The release of progesterone is decreased in CRH- and ACTH-treated trophoblast cell cultures compared to untreated trophoblast cells. Addition of prednisolone in varying concentrations leads to an increase of trophoblast progesterone production.

CONCLUSIONS

The results suggest that CRH and ACTH directly modulate the endocrine function of trophoblasts in culture by downregulating progesterone production. Prednisolone on the other hand showed a stimulating effect on progesterone production in term trophoblast cells in vitro. Because blockade of progesterone is a possible mechanism involved in initiation of labor, we may speculate that CRH and ACTH are directly involved in the auto- or paracrine regulation of this procedure.