Molecular Cloning and Immunologic Characterization of a Novel cDNA Coding for Progesterone-Induced Blocking Factor

PIBF1 regulates trophoblast syncytialization and promotes cardiovascular development

Proper placental development in early pregnancy ensures a positive outcome later on. The developmental relationship between the placenta and embryonic organs, such as the heart, is crucial for a normal pregnancy. However, the mechanism through which the placenta influences the development of embryonic organs remains unclear. Trophoblasts fuse to form multinucleated syncytiotrophoblasts (SynT), which primarily make up the placental materno-fetal interface. We discovered that endogenous progesterone immunomodulatory binding factor 1 (PIBF1) is vital for trophoblast differentiation and fusion into SynT in humans and mice. PIBF1 facilitates communication between SynT and adjacent vascular cells, promoting vascular network development in the primary placenta. This process affected the early development of the embryonic cardiovascular system in mice. Moreover, in vitro experiments showed that PIBF1 promotes the development of cardiovascular characteristics in heart organoids. Our findings show how SynTs organize the barrier and imply their possible roles in supporting embryogenesis, including cardiovascular development. SynT-derived factors and SynT within the placenta may play critical roles in ensuring proper organogenesis of other organs in the embryo.

Progesterone-induced blocking factor blockade causes hypertension in pregnant rats

Preeclampsia (PE) is a multisystem disorder characterized by new onset hypertension in mid-late gestation and can include multi-organ dysfunction with or without proteinuria. It affects 5%-7% of all pregnancies in the U.S., making PE a major contributor to maternal and fetal morbidity and mortality. Currently, there is no cure for this pregnancy complication except for early delivery of the placenta and fetus. Moreover, the therapeutic options to treat PE are very limited. One potential trigger for the development of PE is progesterone deficiency-induced imbalance between T Helper 1(Th1)/Th2 cells, an increase in cytolytic natural killer (NK) cells and inflammatory cytokines that in turn leads to endothelial dysfunction, intrauterine growth restriction (IUGR) and hypertension. Importantly, progesterone signals the synthesis of progesterone-induced blocking factor (PIBF) which has anti-inflammatory effects and could promote the regulation of inflammation balance during pregnancy. However, the role of progesterone and PIBF in the pathophysiology of PE is still not fully understood. Thus, this current study was designed to test the hypothesis that inhibition of PIBF causes signs of PE in pregnant Sprague Dawley rats. In order to address our hypothesis, rabbit anti-PIBF IgG (0.25, low dose-LD or 0.50 mg/mL, high dose-HD) was administered intraperitoneally on gestation day (GD) 15 to normal pregnant Sprague Dawley (NP) rats. On GD 18, carotid catheters were inserted and on GD 19 mean blood pressure (MAP) and samples were collected for further analysis. MAP in normal pregnant rats (NP) rats (n = 7) was 99 ± 3 mmHg, which increased to 116 ± 2 mmHg in NP+ anti-PIBF LD (n = 10) and 113 ± 4 mmHg in NP+ anti-PIBF HD (n = 4), p <0 .05. Plasma TNF-alpha levels were 35 ± 8 pg/mL in NP rats and increased to 84 ± 21 pg/mL in NP+ Anti-PIBF HD (n = 4), p <0 .05. Plasma IL-4 and IL-10 levels were 22 ± 5 and 25+6 pg/mL in NP (n = 5), which decreased to 6 ± 1 and 8 ± 1 pg/mL in NP+ Anti-PIBF LD (n = 6, p < 0.05) and 16 ± 4 and 15 ± 5 pg/mL in NP+ Anti-PIBF HD (n = 4). Circulating total NK cells were 67 ± 11 % gate in NP rats (n = 3), which decreased to 28 ± 7% gate in NP+ Anti-PIBF LD and 45 ± 6% gate in NP+ Anti-PIBF HD. Cytolytic NK cells were increased in NP+ Anti-PIBF HD, p <0 .05. Moreover, circulating NO levels were significantly decreased while renal cortex PPET-1 levels increased NP+ Anti-PIBF HD. Our study demonstrates that PIBF blockade causes hypertension, inflammation and signs of endothelial dysfunction, all of which are associated with PE, thus indicating the importance of progesterone signalling pathways during a healthy pregnancy.

Immunological and Metabolic Causes of Infertility in Polycystic Ovary Syndrome

Infertility has been recognized as a civilizational disease. One of the most common causes of infertility is polycystic ovary syndrome (PCOS). Closely interrelated immunometabolic mechanisms underlie the development of this complex syndrome and lead to infertility. The direct cause of infertility in PCOS is ovulation and implantation disorders caused by low-grade inflammation of ovarian tissue and endometrium which, in turn, result from immune and metabolic system disorders. The systemic immune response, in particular the inflammatory response, in conjunction with metabolic disorders, insulin resistance (IR), hyperadrenalism, insufficient secretion of progesterone, and oxidative stress lead not only to cardiovascular diseases, cancer, autoimmunity, and lipid metabolism disorders but also to infertility. Depending on the genetic and environmental conditions as well as certain cultural factors, some diseases may occur immediately, while others may become apparent years after an infertility diagnosis. Each of them alone can be a significant factor contributing to the development of PCOS and infertility. Further research will allow clinical management protocols to be established for PCOS patients experiencing infertility so that a targeted therapy approach can be applied to the factor underlying and driving the "vicious circle" alongside symptomatic treatment and ovulation stimulation. Hence, therapy of fertility for PCOS should be conducted by interdisciplinary teams of specialists as an in-depth understanding of the molecular relationships and clinical implications between the immunological and metabolic factors that trigger reproductive system disorders is necessary to restore the physiology and homeostasis of the body and, thus, fertility, among PCOS patients.

The role of progesterone and the progesterone receptor in cancer: progress in the last 5 years

INTRODUCTION

Patients with various advanced cancers devoid of nuclear progesterone receptors (nPR) have demonstrated increased quality and length of life when treated with the PR modulator mifepristone, which likely works by interacting with membrane PRs (mPR).

AREAS COVERED

Two immunomodulatory proteins are discussed that seem to play a role in cancers that proliferate whether the malignant tumor is positive or negative for the nPR. These two proteins are the progesterone receptor membrane component-1 (PGRMC-1) and the progesterone-induced blocking factor (PIBF). Both PGRMC-1 and the parent form of PIBF foster increased tumor aggressiveness, whereas splice variants of the 90 kDa form of PIBF inhibit immune response against cancer cells.

EXPERT OPINION

The marked clinical improvement following 200-300 mg of mifepristone is likely related to blocking PIBF. In the low dosage used, mifepristone likely acts as an agonist for PGRMC-1 protein. Mifepristone may be less effective for cancers positive for the nPR because the nPR may be protective and blocking it may have detrimental effects. Based on this hypothetical model, the development of other potential treatment options to provide even greater efficacy for treating cancer are discussed.

A Hypothetical Model Suggesting Some Possible Ways That the Progesterone Receptor May Be Involved in Cancer Proliferation

Cancer and the fetal-placental semi-allograft share certain characteristics, e.g., rapid proliferation, the capacity to invade normal tissue, and, related to the presence of antigens foreign to the host, the need to evade immune surveillance. Many present-day methods to treat cancer use drugs that can block a key molecule that is important for one or more of these characteristics and thus reduce side effects. The ideal molecule would be one that is essential for both the survival of the fetus and malignant tumor, but not needed for normal cells. There is a potential suitable candidate, the progesterone induced blocking factor (PIBF). The parent 90 kilodalton (kDa) form seems to be required for cell-cycle regulation, required by both the fetal-placental unit and malignant tumors. The parent form may be converted to splice variants that help both the fetus and tumors escape immune surveillance, especially in the fetal and tumor microenvironment. Evidence suggests that membrane progesterone receptors are involved in PIBF production, and indeed there has been anecdotal evidence that progesterone receptor antagonists, e.g., mifepristone, can significantly improve longevity and quality of life, with few side effects.

Key to Life: Physiological Role and Clinical Implications of Progesterone

The most recent studies of progesterone research provide remarkable insights into the physiological role and clinical importance of this hormone. Although the name progesterone itself means "promoting gestation", this steroid hormone is far more than a gestational agent. Progesterone is recognized as a key physiological component of not only the menstrual cycle and pregnancy but also as an essential steroidogenic precursor of other gonadal and non-gonadal hormones such as aldosterone, cortisol, estradiol, and testosterone. Based on current findings, progesterone and novel progesterone-based drugs have many important functions, including contraception, treatment of dysfunctional uterine bleeding, immune response, and prevention of cancer. Considering the above, reproduction and life are not possible without progesterone; thus, a better understanding of this essential molecule could enable safe and effective use of this hormone in many clinical conditions.

Biologia futura: embryo-maternal communication via progesterone-induced blocking factor (PIBF) positive embryo-derived extracellular vesicles. Their role in maternal immunomodulation

Paternal antigens expressed by the foetus are recognized as foreign. Therefore,-according to the rules of transplantation immunity-the foetus ought to be "rejected". However, during normal gestation, maternal immune functions are re-adjusted, in order to create a favourable environment for the developing foetus. Some of the mechanisms that contribute to the altered immunological environment, for example, the cytokine balance and NK cell function, with special emphasis on the role of progesterone and the progesterone-induced blocking factor (PIBF) will be reviewed.

Cytokines, Hormones and Cellular Regulatory Mechanisms Favoring Successful Reproduction

Its semi-allogeneic nature renders the conceptus vulnerable to attack by the maternal immune system. Several protective mechanisms operate during gestation to correct the harmful effects of anti-fetal immunity and to support a healthy pregnancy outcome. Pregnancy is characterized by gross alterations in endocrine functions. Progesterone is indispensable for pregnancy and humans, and it affects immune functions both directly and via mediators. The progesterone-induced mediator - PIBF - acts in favor of Th2-type immunity, by increasing Th2 type cytokines production. Except for implantation and parturition, pregnancy is characterized by a Th2-dominant cytokine pattern. Progesterone and the orally-administered progestogen dydrogesterone upregulate the production of Th2-type cytokines and suppress the production of Th1 and Th17 cytokine production in vitro. This is particularly relevant to the fact that the Th1-type cytokines TNF-α and IFN-γ and the Th17 cytokine IL-17 have embryotoxic and anti-trophoblast activities. These cytokine-modulating effects and the PIBF-inducing capabilities of dydrogesterone may contribute to the demonstrated beneficial effects of dydrogesterone in recurrent spontaneous miscarriage and threatened miscarriage. IL-17 and IL-22 produced by T helper cells are involved in allograft rejection, and therefore could account for the rejection of paternal HLA-C-expressing trophoblast. Th17 cells (producing IL-17 and IL-22) and Th22 cells (producing IL-22) exhibit plasticity and could produce IL-22 and IL-17 in association with Th2-type cytokines or with Th1-type cytokines. IL-17 and IL-22 producing Th cells are not harmful for the conceptus, if they also produce IL-4. Another important protective mechanism is connected with the expansion and action of regulatory T cells, which play a major role in the induction of tolerance both in pregnant women and in tumour-bearing patients. Clonally-expanded Treg cells increase at the feto-maternal interface and in tumour-infiltrating regions. While in cancer patients, clonally-expanded Treg cells are present in peripheral blood, they are scarce in pregnancy blood, suggesting that fetal antigen-specific tolerance is restricted to the foeto-maternal interface. The significance of Treg cells in maintaining a normal materno-foetal interaction is underlined by the fact that miscarriage is characterized by a decreased number of total effector Treg cells, and the number of clonally-expanded effector Treg cells is markedly reduced in preeclampsia. In this review we present an overview of the above mechanisms, attempt to show how they are connected, how they operate during normal gestation and how their failure might lead to pregnancy pathologies.

Progesterone-induced blocking factor improves blood pressure, inflammation, and pup weight in response to reduced uterine perfusion pressure (RUPP)

Preeclampsia (PE) is characterized by new-onset hypertension in association with elevated natural killer (NK) cells and inflammatory cytokines, which are likely culprits for decreased fetal weight during PE pregnancies. As progesterone increases during normal pregnancy, it stimulates progesterone-induced blocking factor (PIBF). PIBF has been shown to decrease inflammation and cytolytic NK cells, both of which are increased during PE. We hypothesized that PIBF reduces inflammation as a mechanism to improve hypertension in the preclinical reduced uterine perfusion pressure (RUPP) rat model of PE. PIBF (2.0 µg/mL) was administered intraperitoneally on gestational day 15 to either RUPP or normal pregnant (NP) rats. On day 18, carotid catheters were inserted. Mean arterial blood pressure (MAP) and samples were collected on day 19. MAP in NP rats (n = 11) was 100 ± 2 mmHg and 105 ± 3 mmHg in NP + PIBF rats (n = 8) and 122 ± 1 mmHg in RUPP rats (n = 10), which improved to 110 ± 2 mmHg in RUPP + PIBF rats (n = 11), P < 0.05. Pup weight was 2.4 ± 0.1 g in NP, 2.5 ± 0.1 g in NP + PIBF, 1.9 ± 0.1 g in RUPP, and improved to 2.1 ± 0.1 g in RUPP + PIBF rats. Circulating and placental cytolytic NK cells, IL-17, and IL-6 were significantly reduced while IL-4 and T helper (TH) 2 cells were significantly increased in RUPP rats after PIBF administration. Importantly, vasoactive pathways preproendothelin-1, nitric oxide, and soluble fms-Like tyrosine Kinase-1 (sFlt-1) were normalized in RUPP + PIBF rats compared with RUPP rats, P < 0.05. Our findings suggest that PIBF normalized IL-4/TH2 cells, which was associated with improved inflammation, fetal growth restriction, and blood pressure in the RUPP rat model of PE.

Identification of two novel pathogenic variants of PIBF1 by whole exome sequencing in a 2-year-old boy with Joubert syndrome

Background

Joubert syndrome (OMIM 213300) is an autosomal recessive disorder with gene heterogeneity. Causal genes and their variants have been identified by sequencing or other technologies for Joubert syndrome subtypes.

Case presentation

A two-year-old boy was diagnosed with Joubert syndrome by global development delay and molar tooth sign of mid-brain. Whole exome sequencing was performed to detect the causative gene variants in this individual, and the candidate pathogenic variants were verified by Sanger sequencing. We identified two pathogenic variants (NM_006346.2: c.1147delC and c.1054A > G) of PIBF1 in this Joubert syndrome individual, which is consistent with the mode of autosomal recessive inheritance.

Conclusion

In this study, we identified two novel pathogenic variants in PIBF1 in a Joubert syndrome individual using whole exome sequencing, thereby expanding the PIBF1 pathogenic variant spectrum of Joubert syndrome.

Progesterone induced blocking factor (PIBF) taken in early pregnancy predicts the pregnancy outcome in women undergoing in vitro fertilization procedure

Earlier data suggest a relationship between PIBF concentrations and the outcome of pregnancy. The aim of the study was to compare serum and urine concentrations of PIBF in women with successful pregnancy after IVF with those of women without pregnancy after IVF procedure, and to evaluate the potential relation between PIBF and the outcome of pregnancy. Urine and serum were collected from 120 women, undergoing IVF. 87.5% of patients had primary infertility. 69.2% faced female causes of infertility: 10.8% tubal cause, 11.7% ovulation disorder, and 46.7% other causes of infertility. 30.8% of patients had male factor of infertility. Among non-pregnant women (42) mean concentrations of PIBF in urine and serum were significantly lower (15.8 ng/mL; 148.4 ng/mL) than in women with positive beta HCG value (78) (19.1 ng/mL; 225.9 ng/mL). In 49 patients pregnancy terminated with a term delivery, in 10 patients with pretem delivery, while in 19 patients the pregnancy terminated with a miscarriage. PIBF concentrations in urine (13.9 ± 2.8 ng/mL) and serum (124.6 ± 46.7 ng/mL) samples of women with miscarriage were significantly lower of those with preterm delivery (180.6 ± 54.4 ng/mL; 18.1 ± 4.4 ng/mL) and of those with term delivery (20.4 ± 8.5 ng/mL; 208.7 ± 114.3 ng/mL). Successful pregnancy after IVF procedure is predictable by measuring of urine and serum PIBF concentrations and could be important for predicting of early implantation and pregnancy outcome after IVF procedure and maybe to protect the risk pregnancy.

Characterisation of serum progesterone and progesterone-induced blocking factor (PIBF) levels across trimesters in healthy pregnant women

Progesterone-induced blocking factor (PIBF), which plays an important role in maintaining healthy pregnancies, has shown great promise as a prognostic biomarker for threatened miscarriage. To better characterise the physiological trends of progesterone and PIBF, we analysed serum progesterone and PIBF concentrations in healthy non-pregnant and pregnant women across trimesters. We saw increasing concentrations of progesterone and PIBF in pregnant women with advancing trimesters. The serum progesterone and PIBF percentiles across gestational age in healthy pregnancies can be used as a guide for the formulation of reference ranges. We also demonstrated a significant positive correlation between progesterone and PIBF levels. This study demonstrates increasing progesterone and PIBF concentrations in later trimesters and underscores the importance of progesterone and PIBF in healthy pregnancies. Characterisation of progesterone and PIBF across gestational age in healthy pregnant women may help to prognosticate pregnancy viability and support further research into the importance of progesterone and PIBF in the maintenance of healthy pregnancies.

The immunolocalization of Galectin-1 and Progesterone-Induced Blocking Factor (PIBF) in equine trophoblast: Possible roles in trophoblast invasion and the immunological protection of pregnancy

INTRODUCTION

The proteins galectin-1 and Progesterone Induced Blocking Factor (PIBF) are present on human and murine trophoblast and are thought to influence both immunomodulation and trophoblast invasion. In equids, the invasive component of the placenta, the endometrial cups, stimulate maternal cell-mediated and humoral immune responses. It was therefore of interest to know if galectin-1 or PIBF could be immunolocalised to the invasive and/or non-invasive components of the equine placenta.

MATERIALS

Horse and mule (♀ horse X ♂ donkey) embryos and placental tissues between Days 12 and 124 of gestation were stained immunohistochemically with antibodies raised against galectin-1 and PIBF.

RESULTS

Galectin-1 stained the non-invasive trophoblast between Days 15 and 20 but thereafter stained only the invasive trophoblast cells of the chorionic girdle, both before and after they invaded the endometrium to form the endometrial cups. PIBF, on the other hand, stained both the invasive and non-invasive trophoblast throughout the period of gestation studied. Of particular interest was the relative lack of staining of the endometrial cup cells in mule compared to horse pregnancies for galectin-1 and PIBF prior to the earlier and more rapid death and desquamation of the mule cup cells.

DISCUSSION

The expression of galectin-1 and PIBF proteins in equine trophoblast and the marked difference in lifespan between the endometrial cups in intraspecies horse versus interspecies mule pregnancies support a likely role for these two proteins protecting the fetal trophoblast from maternal immune attack and/or modulation of the invasiveness of endometrial cup cells.

Progestogens and immunology

Fifty percent of fetal antigens are of paternal origin. These are recognized by the maternal immune system, thereby resulting in lymphocyte activation and the induction of progesterone receptors (PRs) in immune cells. Upon binding of progesterone to PRs on lymphocytes, a downstream mediator called progesterone-induced blocking factor (PIBF) is produced. The full-length PIBF is a 90 kDa protein; however, because of alternative splicing, several smaller isoforms are also produced. While the 90 kDa molecule plays a role in cell cycle regulation, the small isoforms are localized in the cytoplasm, and after secretion, they bind to their receptors on other cells and act in a cytokine-like manner. The communication between the embryo and the maternal immune system is established through PIBF-containing extracellular vesicles. PIBF induces an increased production of Th2 cytokines and inhibits degranulation of NK cells, and by regulating the maternal immune response, it contributes to successful implantation and maintenance of pregnancy.

The involvement of the progesterone receptor in PIBF and Gal-1 expression in the mouse endometrium

PROBLEM

The progesterone-regulated genes, PIBF and Gal-1, are key players in the feto-maternal immunological interaction. This study aims to investigate the expression of PIBF and Gal-1 in WT and progesterone receptor KO models as well as subsequent effects of PIBF on decidualization of stromal cells.

METHOD OF THE STUDY

PRAKO, PRBKO and PRKO BALB/c mice were used for assessing the role of PR isoforms in PIBF induction. PIBF- and Gal-1 mRNA expression in the uterus was tested by real-time PCR. The effect of PIBF on decidualization of endometrial stromal cells was verified by anti-desmin immunofluorescence. Immunohistochemistry was used for testing PIBF expression in the uterus. Gal-1, ERα and PR positive decidual NK cells were detected by immunofluorescence.

RESULTS

PIBF mRNA was significantly increased in progesterone-treated WT mice, but not in PRKO and PRAKO mice. PIBF protein expression was reduced in the endometria of PRKO and PRAKO, but not in PRBKO mice. During a 6-day culture, PIBF induced decidual transformation of endometrial stromal cells. PIBF expression in the mouse uterus was highest during the implantation window, while Gal-1 mRNA expression continuously increased between day 2.5 and day 11.5 of gestation. Decidual NK cells express Gal-1 and ERα, but not PR at day 7.5 murine pregnancy.

CONCLUSION

PIBF produced via engagement of PRA, is highly expressed in the endometrium during the implantation window, and plays a role in decidualization. The concerted action of PIBF and Gal-1 might contribute to the low cytotoxic activity of decidual NK cells.

The Frog Xenopus as a Model to Study Joubert Syndrome: The Case of a Human Patient With Compound Heterozygous Variants in PIBF1

Joubert syndrome (JS) is a congenital autosomal-recessive or—in rare cases–X-linked inherited disease. The diagnostic hallmark of the so-called molar tooth sign describes the morphological manifestation of the mid- and hind-brain in axial brain scans. Affected individuals show delayed development, intellectual disability, ataxia, hyperpnea, sleep apnea, abnormal eye, and tongue movements as well as hypotonia. At the cellular level, JS is associated with the compromised biogenesis of sensory cilia, which identifies JS as a member of the large group of ciliopathies. Here we report on the identification of novel compound heterozygous variants (p.Y503C and p.Q485^*) in the centrosomal gene PIBF1 in a patient with JS via trio whole exome sequencing. We have studied the underlying disease mechanism in the frog Xenopus, which offers fast assessment of cilia functions in a number of embryological contexts. Morpholino oligomer (MO) mediated knockdown of the orthologous Xenopus pibf1 gene resulted in defective mucociliary clearance in the larval epidermis, due to reduced cilia numbers and motility on multiciliated cells. To functionally assess patient alleles, mutations were analyzed in the larval skin: the p.Q485^* nonsense mutation resulted in a disturbed localization of PIBF1 to the ciliary base. This mutant failed to rescue the ciliation phenotype following knockdown of endogenous pibf1. In contrast, the missense variant p.Y503C resulted in attenuated rescue capacity compared to the wild type allele. Based on these results, we conclude that in the case of this patient, JS is the result of a pathogenic combination of an amorphic and a hypomorphic PIBF1 allele. Our study underscores the versatility of the Xenopus model to study ciliopathies such as JS in a rapid and cost-effective manner, which should render this animal model attractive for future studies of human ciliopathies.

The Role of Extracellular Vesicles and PIBF in Embryo-Maternal Immune-Interactions

Pregnancy represents a unique immunological situation. Though paternal antigens expressed by the conceptus are recognized by the immune system of the mother, the immune response does not harm the fetus. Progesterone and a progesterone induced protein; PIBF are important players in re-adjusting the functioning of the maternal immune system during pregnancy. PIBF expressed by peripheral pregnancy lymphocytes, and other cell types, participates in the feto-maternal communication, partly, by mediating the immunological actions of progesterone. Several splice variants of PIBF were identified with different physiological activity. The full length 90 kD PIBF protein plays a role in cell cycle regulation, while shorter splice variants are secreted and act as cytokines. Aberrant production of PIBF isoforms lead to the loss of immune-regulatory functions, resulting in and pregnancy failure. By up regulating Th2 type cytokine production and by down-regulating NK activity, PIBF contributes to the altered attitude of the maternal immune system. Normal pregnancy is characterized by a Th2-dominant cytokine balance, which is partly due to the action of the smaller PIBF isoforms. These bind to a novel form of the IL-4 receptor, and induce increased production of IL-3, IL-4, and IL-10. The communication between the conceptus and the mother is established via extracellular vesicles (EVs). Pre-implantation embryos produce EVs both in vitro, and in vivo. PIBF transported by the EVs from the embryo to maternal lymphocytes induces increased IL-10 production by the latter, this way contributing to the Th2 dominant immune responses described during pregnancy.

The Role of Progesterone in Feto-Maternal Immunological Cross Talk

This review aims to provide a brief historical overview of the feto-maternal immunological relationship, which profoundly influences the outcome of pregnancy. The initial question posed in the 1950s by Medawar [Symp Soc Exp Biol. 1953; 7: 320-338] was based on the assumption that the maternal immune system recognizes the fetus as an allograft. Indeed, based on the association between HLA-matching and spontaneous miscarriage, it became obvious that immunological recognition of pregnancy is required for a successful gestation. The restricted expression of polymorphic HLA antigens on the trophoblast, together with the presence of nonpolymorphic MHC products, excludes recognition by both T and NK cells of trophoblast-presented antigens; however, γδ T cells, which constitute the majority of decidual T cells, are likely candidates. Indeed, a high number of activated, progesterone receptor-expressing γδ T cells are present in the peripheral blood of healthy pregnant women and, in the presence of progesterone, these cells secrete an immunomodulatory protein called progesterone-induced blocking factor (PIBF). As early as in the peri-implantation period, the embryo communicates with the maternal immune system via PIBF containing extracellular vesicles. PIBF contributes to the dominance of Th2-type reactivity which characterizes normal pregnancy by inducing increased production of Th2 cytokines. The high expression of this molecule in the decidua might be one of the reasons for the low cytotoxic activity of decidual NK cells.

The effect of the Progesterone-Induced Blocking Factor (PIBF) on E-cadherin expression, cell motility and invasion of primary tumour cell lines

In addition to being immunomodulatory, Progesterone-Induced Blocking Factor (PIBF) plays a role in cell cycle regulation and invasion. The full length protein is associated with the pericentriolar satellites and as such, it is crucial for maintaining the integrity of spindle poles during mitosis. Another suggestive evidence for the involvement of PIBF in tumour progression is the fact that the PIBF gene has been identified on chromosome 13 in the region associated with breast cancer susceptibility. Earlier we showed that PIBF differentially regulates the invasiveness of trophoblast and tumour cell lines. The aim of the present study was to further investigate the role of PIBF in tumour development, using primary ovarian- (OC) and primary lung carcinoma (LC) cell cultures, and JEG-3 choriocarcinoma cell line. In the cultured cells PIBF was knocked down by siRNA treatment, and the impact of PIBF deficiency on MMP-9 activity and E-cadherin expression as well as on invasive and migratory capacity of the cells was tested. In conditioned media of PIBF-deficient JEG-3 cells, LC cells and OC cells MMP-9 activity was reduced to 36% 35%, and 65% respectively compared to controls. Though PIBF knock down did not affect migration, in JEG-3 cells, LC primary cells and OC primary cells PIBF deficiency resulted 20%, 50% and 50% decrease of invasion respectively. PIBF silencing resulted in increased E-cadherin expression, suggesting that by down regulating E-cadherin expression, PIBF might interfere with the cell-cell adhesion mechanisms and by increasing MMP activity induced extracellular matrix degradation, facilitates the invasion of tumour cells.

The role of progesterone and the progesterone receptor in cancer

There is an abundance of accumulating data strongly suggesting there is a key role for the progesterone receptor in the molecular events effecting the growth or containment of a variety of cancers. This knowledge should lead to novel new strategies to combat various cancers, including drugs classified as progesterone receptor modulators or monoclonal antibodies against some of the key proteins needed for cancer proliferation by suppressing immune surveillance. Areas covered: The role of the classic nuclear receptor and molecular events needed for proliferation are reviewed including cancers of the breast, endometrium, prostate, thyroid, and leiomyomas and leiomyosarcoma. The potential role of non-genomic membrane progesterone receptors is reviewed. The prognostic role of the presence of progesterone receptors is also discussed. Over 1000 research publications were read after conducting a PubMed search. Expert commentary: Discussion is made about a unique immunomodulatory protein called the progesterone induced blocking factor (PIBF). The role of this protein, that is unique to rapidly growing cells, may hold a key to how the cancer cells escape immune surveillance. Thus, techniques to suppress the intracytoplasmic isoforms of PIBF may play a significant role in the fight against all cancers, not just the ones with the classic nuclear progesterone receptors.

Dydrogesterone and the immunology of pregnancy

Progesterone is indispensable for the maintenance of pregnancy, both via its endocrine effects and its role in creating a favorable immunological environment for the fetus. This review focuses on the immunological effects of progesterone. Progestogens have been shown to have very interesting effects on cytokine production and decidual natural killer (NK) cell activity. The orally-administered progestogen, dydrogesterone, has the ability to modulate cytokine production patterns in a manner that could be conducive to successful pregnancy. The adverse effects of progesterone deficiency and the beneficial effects of progesterone supplementation in pregnancy pathologies will be discussed.

Interleukin-33-induced expression of PIBF1 by decidual B cells protects against preterm labor

Preterm birth (PTB) is a leading cause of neonatal death worldwide. Intrauterine and systemic infection and inflammation cause 30-40% of spontaneous preterm labor (PTL), which precedes PTB. Although antibody production is a major immune defense mechanism against infection, and B cell dysfunction has been implicated in pregnancy complications associated with PTL, the functions of B cells in pregnancy are not well known. We found that choriodecidua of women undergoing spontaneous PTL harbored functionally altered B cell populations. B cell-deficient mice were markedly more susceptible than wild-type (WT) mice to PTL after inflammation, but B cells conferred interleukin (IL)-10-independent protection against PTL. B cell deficiency in mice resulted in a lower uterine level of active progesterone-induced blocking factor 1 (PIBF1), and therapeutic administration of PIBF1 mitigated PTL and uterine inflammation in B cell-deficient mice. B cells are a significant producer of PIBF1 in human choriodecidua and mouse uterus in late gestation. PIBF1 expression by B cells is induced by the mucosal alarmin IL-33 (ref. 9). Human PTL was associated with diminished expression of the α-chain of IL-33 receptor on choriodecidual B cells and a lower level of active PIBF1 in late gestation choriodecidua. These results define a vital regulatory cascade involving IL-33, decidual B cells and PIBF1 in safeguarding term pregnancy and suggest new therapeutic approaches based on IL-33 and PIBF1 to prevent human PTL.

PIBF positive uterine NK cells in the mouse decidua

Though uterine NK cells (u NK cells) contain cytotoxic granules, and selectively over- express the genes of perforin and granzymes, during normal pregnancy, they are not cytotoxic. Progesterone is indispensable for the establishment and maintenance of pregnancy both in humans and in mice. Mouse uterine NK cells do not express the classical progesterone receptor, yet progesterone affects the recruitment and function of uterine NK cells, the latter partly via the Progesterone-Induced Blocking Factor (PIBF). We demonstrated PIBF positive granulated cells in the mouse decidua. The aim of this study was to characterize these cells by lectin immunohistochemistry and anti-perforin reactivity. PIBF+ granulated cells were absent from the deciduae of alymphoid mice, but appeared in the decidua of those that had been reconstituted with bone marrow from male BALB/c mice. PIBF+ granulated cells bound the DBA lectin, suggesting their NK cell nature, and also contained perforin, which co-localized with PIBF in the cytoplasmic granules. In anti-progesterone treated mice all of the PIBF+ cells were perforin positive at g. d. 12.5, in contrast to the 54% perforin positivity of PIBF+ cells in untreated mice.

CONCLUSION

The PIBF+ granulated cells in the decidua belong to the NK population, and PIPB co-localizes with perforin in the cytoplasmic granules.

Preterm delivery and associated negative pregnancy outcome - A tale of faulty progesterone receptor signalling pathway and linked derailed immunomodulation: A study from Northeast India

Preterm delivery (PTD) is one of the potent contributor of neonatal mortality and morbidity, and the underlying cause in some situation is elusive. This study attempts to delineate the association of deregulation in progesterone receptor (PR) pathway and deleterious immune responses in predisposing patients to PTD in Northeast India, a region with high rate of PTD cases. A total of 109 cases of PTD and 100 term delivery cases were enrolled with all clinical details. The PTD cases were stratified based on gestation age at delivery. The differential expression of PR and key downstream effectors and cytokines were evaluated for correlation with PTD susceptibility, gestational period, and pregnancy outcome. The results indicated a sharp downregulation in PR expression is associated with PTD susceptibility, lower gestational period and negative pregnancy outcome. The PR downstream effector PIBF was also found to be downregulated in PTD, and is associated with gestational period and negative pregnancy outcome. The downregulation of PR and PIBF expression was found to correlate with a predominant Th1 state with higher CD56+NK cell counts and pro-inflammatory burst lead by hyper TNF-α, NF-kB and IFNγ expression, and complicated by lower IL10 expression, contributing to PTD as well as negative pregnancy outcome in the PTD cases. TNF-α expression in placenta inversely correlated with placental PR expression. To conclude, deregulation in PR pathway is a hallmark of preterm delivery and negative pregnancy outcome. Differential expression of several markers such as PR, PIBF and TNF-α has prognostic significance, and hence is of clinical significance.

Evidence that exposure to progesterone alone is a sufficient stimulus to cause a precipitous rise in the immunomodulatory protein the progesterone induced blocking factor (PIBF)

PURPOSE

To determine if exposure to progesterone alone is sufficient to increase the production of the immunomodulatory protein known as the progesterone induced blocking factor (PIBF). Also to determine what method of progesterone delivery or form of P best stimulates PIBF secretion.

METHODS

Serum samples from patients with infertility and paid volunteers were evaluated for both PIBF and progesterone at various times during the follicular phase and the luteal phase in both natural cycles and cycles involving embryo transfer after endogenous and exogenous progesterone exposure and after various synthetic progestins. PIBF was measured by a non-commercial research ELISA assay. Comparisons were made of serum PIBF before and after exposure to progesterone, 17-hydroxyprogesterone, and oral contraceptives. PIBF was also measured before and after transfer of embryos.

RESULTS

Progesterone alone without exposure to the fetal allogeneic stimulus was able to produce a marked increase in serum PIBF. Neither a synthetic progestin (19-nortestosterone derivative) nor 17-hydroxyprogesterone caused an increase in PIBF. Some PIBF is generally detected even in the follicular phase.

CONCLUSIONS

A previous concept considered that an allogeneic stimulus, e.g., from the fetal semi-allograft, was necessary to induce de novo progesterone receptors in gamma delta T cells, which, in turn, when exposed to a high concentration of progesterone, would secrete high levels of PIBF. These data show that exposure to an allogeneic stimulus is not needed to cause a marked rise in PIBF, merely progesterone alone is sufficient.

High Prevalence and Clinical Relevance of Genes Affected by Chromosomal Breaks in Colorectal Cancer

Background

Cancer is caused by somatic DNA alterations such as gene point mutations, DNA copy number aberrations (CNA) and structural variants (SVs). Genome-wide analyses of SVs in large sample series with well-documented clinical information are still scarce. Consequently, the impact of SVs on carcinogenesis and patient outcome remains poorly understood. This study aimed to perform a systematic analysis of genes that are affected by CNA-associated chromosomal breaks in colorectal cancer (CRC) and to determine the clinical relevance of recurrent breakpoint genes.

Methods

Primary CRC samples of patients with metastatic disease from CAIRO and CAIRO2 clinical trials were previously characterized by array-comparative genomic hybridization. These data were now used to determine the prevalence of CNA-associated chromosomal breaks within genes across 352 CRC samples. In addition, mutation status of the commonly affected APC, TP53, KRAS, PIK3CA, FBXW7, SMAD4, BRAF and NRAS genes was determined for 204 CRC samples by targeted massive parallel sequencing. Clinical relevance was assessed upon stratification of patients based on gene mutations and gene breakpoints that were observed in >3% of CRC cases.

Results

In total, 748 genes were identified that were recurrently affected by chromosomal breaks (FDR <0.1). MACROD2 was affected in 41% of CRC samples and another 169 genes showed breakpoints in >3% of cases, indicating that prevalence of gene breakpoints is comparable to the prevalence of well-known gene point mutations. Patient stratification based on gene breakpoints and point mutations revealed one CRC subtype with very poor prognosis.

Conclusions

We conclude that CNA-associated chromosomal breaks within genes represent a highly prevalent and clinically relevant subset of SVs in CRC.

Maternal serum progesterone-induced blocking factor (PIBF) in the prediction of preterm birth

The objective of this study was to analyze the maternal serum concentration of progesterone-induced blocking factor (PIBF) with regard to the prediction and the interval between sampling and the onset of preterm birth. A prospective study was conducted on a sample of 37 women with threatened pre-term birth and 41 healthy pregnant women between the 24th and 28th gestational weeks. Out of 37 patients with threatened preterm birth 11 delivered pre-term and three groups of patients were formed: the preterm delivery group, patients with threatened preterm delivery, and healthy pregnant women. In samples that were taken within 5 days before labor started (6/11, 54.5%), PIBF concentrations were significantly lower than in those obtained more than 5 days before labor (5/11, 45.5%; the mean interval between sampling and the onset of labor was 4.1 ± 1.8 days). Multiple regression analysis of the individual contributions of each observed parameter for preterm delivery demonstrated the significant contribution of a lack of PIBF to preterm birth (p = 0.002). Receiver operating characteristics (ROC) analysis was performed to evaluate the diagnostic accuracy of PIBF for the prediction of preterm birth of women with symptoms of pre-term delivery. The PIBF demonstrated an excellent diagnostic value in the prediction of preterm birth with an area under the ROC curve (AUC) of 0.956 (95% CI = 0.884-0.989; p < 0.0001). Our data suggest that pregnancy termination can be predicted by lower than normal pregnancy PIBF values within 5 days before labor and can contribute to the diagnosis of preterm birth.

Glucocorticoid Regulation of Reproduction

It is well accepted that stress, measured by increased glucocorticoid secretion, leads to profound reproductive dysfunction. In times of stress, glucocorticoids activate many parts of the fight or flight response, mobilizing energy and enhancing survival, while inhibiting metabolic processes that are not necessary for survival in the moment. This includes reproduction, an energetically costly procedure that is very finely regulated. In the short term, this is meant to be beneficial, so that the organism does not waste precious energy needed for survival. However, long-term inhibition can lead to persistent reproductive dysfunction, even if no longer stressed. This response is mediated by the increased levels of circulating glucocorticoids, which orchestrate complex inhibition of the entire reproductive axis. Stress and glucocorticoids exhibits both central and peripheral inhibition of the reproductive hormonal axis. While this has long been recognized as an issue, understanding the complex signaling mechanism behind this inhibition remains somewhat of a mystery. What makes this especially difficult is attempting to differentiate the many parts of both of these hormonal axes, and new neuropeptide discoveries in the last decade in the reproductive field have added even more complexity to an already complicated system. Glucocorticoids (GCs) and other hormones within the hypothalamic-pituitary-adrenal (HPA) axis (as well as contributors in the sympathetic system) can modulate the hypothalamic-pituitary-gonadal (HPG) axis at all levels-GCs can inhibit release of GnRH from the hypothalamus, inhibit gonadotropin synthesis and release in the pituitary, and inhibit testosterone synthesis and release from the gonads, while also influencing gametogenesis and sexual behavior. This chapter is not an exhaustive review of all the known literature, however is aimed at giving a brief look at both the central and peripheral effects of glucocorticoids on the reproductive function.

The immune privilege of testis and gravid uterus: same difference?

The fetus in the gravid uterus and the developing spermatogenic cells in the adult testis both comprise special challenges for the host immune system. Protection of the neoantigens of the fetus and male germ cells from immune attack, defined as immune privilege, is fundamental for the propagation of species. Immune privilege is not simply the absence of leukocytes, but involves immune and non-immune cells acting synergistically together at multiple levels to create a unique tolerogenic environment. A number of the pathways are shared by the testis and gravid uterus. Amongst them steroid hormones, namely testosterone in the male and progesterone in the female, seem to function as key molecules that govern the local production of immunoregulatory factors which finally control the overall immune environment.

Progesterone-induced blocking factor differentially regulates trophoblast and tumor invasion by altering matrix metalloproteinase activity

Invasiveness is a common feature of trophoblast and tumors; however, while tumor invasion is uncontrolled, trophoblast invasion is strictly regulated. Both trophoblast and tumor cells express high levels of the immunomodulatory progesterone-induced blocking factor (PIBF), therefore, we aimed to test the possibility that PIBF might be involved in invasion. To this aim, we used PIBF-silenced or PIBF-treated trophoblast (HTR8/Svneo, and primary trophoblast) and tumor (HT-1080, A549, HCT116, PC3) cell lines. Silencing of PIBF increased invasiveness as well as MMP-2,-9 secretion of HTR8/SVneo, and decreased those of HT-1080 cells. PIBF induced immediate STAT6 activation in both cell lines. Silencing of IL-4Rα abrogated all the above effects of PIBF, suggesting that invasion-related signaling by PIBF is initiated through the IL-4Rα/PIBF-receptor complex. In HTR-8/SVneo, PIBF induced fast, but transient Akt and ERK phosphorylation, whereas in tumor cells, PIBF triggered sustained Akt, ERK, and late STAT3 activation. The late signaling events might be due to indirect action of PIBF. PIBF induced the expression of EGF and HB-EGF in HT-1080 cells. The STAT3-activating effect of PIBF was reduced in HB-EGF-deficient HT-1080 cells, suggesting that PIBF-induced HB-EGF contributes to late STAT3 activation. PIBF binds to the promoters of IL-6, EGF, and HB-EGF; however, the protein profile of the protein/DNA complex is different in the two cell lines. We conclude that in tumor cells, PIBF induces proteins, which activate invasion signaling, while-based on our previous data-PIBF might control trophoblast invasion by suppressing proinvasive genes.

The role of progesterone and the progesterone receptor in human reproduction and cancer

Insufficient progesterone, effect possibly more on immune factors rather than adequate endometrial development, can be an easy remedial cause of infertility by simply supplementing the luteal phase with either vaginal or intramuscular or oral (dydrogesterone) progesterone. Progesterone will also help to reduce miscarriage rates when follicle maturing drugs are used for those with regular menses but follicular maturation defects, or women with recurrent miscarriages. One mechanism of action seems to be related to production of an immunomodulatory protein, the progesterone-induced blocking factor either in the cytoplasm or in the circulation. PIBF inhibits cytotoxicity of natural killer cells. Cancer cells may 'borrow' the same mechanism to escape NK cell immunosurveillance.

A cross-talk of decidual stromal cells, trophoblast, and immune cells: a prerequisite for the success of pregnancy

Embryo implantation and formation of a functional placenta are complex processes that require a plethora of regulatory mechanisms involving both mother and embryo cells. Recently, an important role in this complicated cells and factors network was assigned to the decidual stromal cells (DSC) and trophoblast cells. Decidualization includes biochemical changes that trigger DSC to produce a number of factors required for the implantation and induction of immunotolerance in maternal immune system. Immunotolerance is achieved by a cascade of strictly controlled events starting with selective homing of immune cells to the feto-maternal site, regulated proliferation, and predominant differentiation into a regulatory type of immune cells. Furthermore, cytotoxic effector functions are reduced owing to the influence of steroid hormones, factors, cytokines, and inhibitory receptors. Altogether the entire immune system of the mother is switched to tolerogenic functional state which is a prerequisite for the successful maintenance of pregnancy.

Changes of progesterone-induced blocking factor in patients after kidney transplantation

The prediction of graft rejection can play an important part in graft survival. Analysis of immune reactions has shown that graft rejection shares mechanisms with recurrent abortions during pregnancy. Progesterone-induced blocking factor (PIBF), a mediator of progesterone that blocks natural killer cell activity in peripheral blood, produces antiabortive effects. The aim of this study was to examine the PIBF concentration in the urine of transplanted recipients. The study included 116 white adults (70 men and 46 women) of median age 49.3 years, who had undergone kidney transplantations. The median duration after transplantation was 3.46 years. The average period between renal disease and our measurement was 12.3 years, and the median interval between graft rejection and our study was 1.75 years. Urine samples were used to measure PIBF concentrations by an enzyme-linked immunsorbent assay. PIBF urinary concentrations decreased significantly in patients who experienced ≥1 rejection episode (31.8±2.2 ng/mL) compared with those without any episode (22.7±1.2 ng/ml; P<.01). Moreover, the urinary PIBF level was significantly lower among patients who had increased creatinine and urea nitrogen levels in blood samples (P<.05 and P<.01, respectively). Decreased PIBF values in kidney transplant patients followed previous rejection episodes. A close negative correlation was observed between urinary PIBF concentrations and blood levels of creatinine and urea nitrogen. These findings suggested that PIBF detection may predict graft rejection in transplant recipients.

Barriers of the Human Organism and Their Achilles’ Heels

The human body is covered by barriers separating it from the external and internal surroundings. The “milieu enterieur” has to be stabilised in spite of the variable external and internal conditions of toxic, osmotic, microbial and climatic environmental circumstances. This first line of barriers is composed of skin and mucous membranes of complicated structures.

A second line of barrier system is present in our organisms. Certain organs have to be separated from the immune system and other parts of the body because of evolutionary reasons (eye-bulb and testicles) because of unique proteins “unknown” for the acquired immune system. The blood-brain barrier (BBB) is providing enhanced safety circumstances for the central nervous system. The second line of barriers is represented by the special properties of the capillary endothelial system.

The maternal-fetal barrier is the most complex. At the maternal fetal interface two individuals of two different haplotypes has to be live 9 months separated by a very complicated dynamic barrier.

The placenta is the organ, which is separating the maternal and fetal tissues. Similar to others the bidirectional transport of gasses, metabolites, cells, proteins, regulatory substances, are transported by active or passive transcellular and intercellular mechanisms.

The fetal immune system develops immunotolerance to all maternal cells and antigens transferred transplacentally. The problem is to mitigate the maternal immune system to tolerate the paternal haplotype of the fetus. In the case of normal pregnancy a complex series of physiological modifications can solve the problem without harmful consequences to the mother and fetus.

The outermost contact cells of trophoblasts express instead of HLA-class Ia and class II antigens non-variable HLA-C, HLA-E, HLA-F and HLA-G antigens. The first consequence of this is reduction of the activity of maternal natural killer cells and maternal dendritic cells;

Progesteron, micro-RNA and mediators influence the development of T effector-cells. The production of soluble HLA-G(5 and 6) and IL-10 supports the differentiation of Th-2 CD4⁺ helper cells, reducing the ability of maternal cells to kill fetal cells.

Series of receptors and costimulators are expressed by the different lines of semi-allogenic trophoblast cells to bind HLA-G and mitigate maternal immune response;

The maternal immunotolerance is further facilitated by the activation of CD4⁺CD25^brightFoxp3⁺ regulatory T (T_REG) cells.

Infections have to be prevented during pregnancy. The cells of placenta express 10 Toll-like receptors a group of pattern recognition receptors responsible for innate immunity. The interferon level is also higher in the placental tissues than in the somatic fetal or maternal cells.

The complement system is also adapted to the requirements of the pregnancy and fetal damage is inhibited by the production of “assymmetric IgG antibodies” under hormonal and placental-regulation. These modifications prevent the activation of complement, cytotoxic activity, opsonising ability, antigen clearance and precipitating activity of the molecules.

The Achilles’ heels of the different barriers are regularly found by virus infections. Lamina cribrosa of the blood-brain barrier, optical nerve of the eyes, etc. the risk factors of the maternal-fetal barrier has been summarised in Table 1.1.

Dydrogesterone supplementation in women with threatened preterm delivery--the impact on cytokine profile, hormone profile, and progesterone-induced blocking factor

Progesterone is indispensable in creating a suitable endometrial environment for implantation, and also for the maintenance of pregnancy. Successful pregnancy depends on an appropriate maternal immune response to the fetus. A protein called progesterone-induced blocking factor (PIBF) acts by inducing Th2-dominant cytokine production to mediate the immunological effects of progesterone. The aim of this prospective study was to compare serum concentrations of progesterone (P), estradiol (E2), anti-inflammatory (IL-10) and pro-inflammatory (IL-6, TNFα, IFNγ) cytokines, and serum PIBF concentrations in women with threatened preterm delivery who were given progesterone supplementation (study group) with those of women with threatened preterm delivery who were not given progesterone supplementation (control group). After dydrogesterone treatment of patients in the study group, serum PIBF as well as progesterone concentrations significantly increased. Women in this group had significantly higher serum levels of IL-10 than controls. The length of gestation was significantly higher in the group of women who were given progesterone supplementation. Our data suggest that dydrogesterone treatment of women at risk of preterm delivery results in increased PIBF production and IL-10 concentrations, and lower concentrations of IFNγ.

High viral load and deregulation of the progesterone receptor signaling pathway: association with hepatitis E-related poor pregnancy outcome

BACKGROUND & AIMS

Hepatitis E virus (HEV) infection is associated with high maternal and fetal mortalities. A prospective study was undertaken to evaluate the role of viral and host factors in HEV related pregnancy outcomes.

METHODS

The study included HEV infected pregnancy cases; acute viral hepatitis (AVH), n=100 and fulminant hepatic failure (FHF), n=43, and healthy pregnancy cases, n=50. HEV genotypes and viremia were studied by nucleotide sequencing and real time PCR, respectively. Progesterone receptor (PR) gene mutations (PROGINS) were studied by PCR, PR expression at the mRNA and protein levels in the placenta were studied by semi-quantitative RT-PCR and immunohistochemistry, respectively. Progesterone induced blocking factor (PIBF) expression was studied by RT-PCR in blood. Serum interleukin-10 (IL-10) and interleukin-12 (IL-12) levels were assayed by ELISA.

RESULTS

HEV viral load was significantly higher in FHF than AVH (p<0.001) and in cases with fetal mortality in AVH (p=0.001) and FHF (p=0.018). PROGINS were predominant in FHF compared to AVH (p=0.26) and showed reduced mRNA and protein expression. The risk of fetal mortality in AVH was two times higher (OR, 2.190; CI, 0.303-15.85) and maternal and fetal mortalities in FHF were 4-fold (OR, 4.0; CI, 0.363-44.113) increased in PROGINS carriers. PR and PIBF expression was lower in AVH and even lower in FHF compared to healthy controls. The higher IL-12/IL-10 ratio observed in FHF compared to other groups correlated with fetal mortality in AVH and FHF (p<0.001).

CONCLUSIONS

In conclusion, reduced expression of PR and PIBF, a higher IL-12/IL-10 ratio, and a high viral load results in poor pregnancy outcome in Hepatitis E.

The pericentriolar satellite protein CEP90 is crucial for integrity of the mitotic spindle pole

Pericentriolar satellites are electron-dense granules that are concentrated around the centrosome. They are involved in the recruitment of centrosomal proteins and microtubule organization in interphase cells, but their mitotic functions are largely unknown. In this study, we characterize CEP90 as a component of pericentriolar satellites. CEP90 is present both in the centrosome and in the cytoplasm, but is transiently concentrated at the centrosome once cells enter mitosis. Depletion of CEP90 caused mitotic arrest with misaligned chromosomes. Spindle pole fragmentation was the most characteristic phenotype in CEP90-depleted cells. Spindle poles were fragmented as soon as the spindles attached, suggesting that the mechanical forces of spindle microtubules physically stress the structure of CEP90-depleted spindle poles. Based on these results, we propose that CEP90 is crucial for maintaining the integrity of spindle poles during mitosis.

Immunology of pregnancy

The conceptual framework for reproductive immunology was put in place over 50 years ago when the survival of the fetal semi-allograft within an immunocompetent mother was first considered. During this time, a number of paradigms have emerged and the mechanisms receiving current attention are those related to immune tolerance, such as regulatory T-cells and indoleamine 2,3,-dioxygenase, and innate immunity, such as natural killer cells, trophoblast debris and inflammation. A key consideration is the temporal and spatial variation in any of these pathways (e.g. implantation v. parturition). As fetally derived trophoblasts are the semi-allogeneic cells with which the maternal immune system comes into contact, understanding the immune response to these cells is critical. There is much interest in the immunological pathways that support a healthy pregnancy and how they might be perturbed in adverse pregnancy outcomes. Additionally, there is increasing awareness that antenatal determinants of the immune function of pregnant women and their offspring have consequences for health and disease in childhood and beyond. Changes in maternal diet over recent decades coincide with the increasing prevalence of allergic and other immune-mediated diseases, and the modification of maternal diet has emerged as a strategy for disease prevention. Approaches undergoing trial at numerous sites around the world include dietary supplementation with fish oil and/or probiotics. Understanding the underlying mechanisms of any positive effect on disease outcomes should reveal further novel strategies for disease prevention.

New target cells of the immunomodulatory effects of progesterone

It is well known that the reproductive steroid hormones, particularly progesterone, in addition to its widely recognized effects on endometrial epithelial and stromal cells and spiral arteries, affect the activities of T cells and natural killer cells in the deciduas, thus inducing active immune tolerance against the fetal antigens. The immunomodulatory effects of progesterone on T cells, B cells and natural killer cells have been discussed extensively in the literature. The aim of the present review is to sum up and discuss the results from this and other laboratories of investigations on the effects of progesterone on dendritic cells and adult stem cells, which are some of the other cell populations present at the fetal-maternal interface and possibly are related to the immunoregulation during pregnancy. These cells have been shown to have a number of specific functions but their involvement in the entire process of regulation of the immune response in pregnancy is still under discussion. The present review focuses on facts showing that the progesterone is a kind of 'regulator of regulators' in the decidua, thus creating the most favourable conditions for the development of the semi-allogeneic fetus in successful pregnancy.

PIBF: the double edged sword. Pregnancy and tumor

PROBLEM

The role of progesterone-dependent immunomodulation in the maintenance of normal pregnancy.

METHODS

In vitro and in vivo data on the effect that progesterone and its mediator progesterone-induced blocking factor (PIBF) exert on the immune functions of pregnant women are reviewed, together with clinical findings.

RESULTS

Activated pregnancy lymphocytes express progesterone receptors, which enable progesterone to induce a protein called PIBF. PIBF increases Th2 type cytokine production by signaling via a novel type of IL-4 receptor and activating the Jak/STAT pathway. PIBF inhibits phosholipase A2, thus reduces prostaglandin synthesis. PIBF inhibits perforin release in human decidual lymphocytes and reduces the deleterious effect of high NK activity on murine pregnancy. PIBF production is a characteristic feature of normal human pregnancy, and its concentration is reduced in threatened pregnancies. PIBF mRNA and protein are expressed in a variety of malignant tumors. Inhibition of PIBF synthesis increases survival rates of leukemic mice.

CONCLUSION

Progesterone-induced blocking factor is produced by pregnancy lymphocytes and also by malignant tumors. The PIBF-induced Th2-dominant immune response is favorable during pregnancy but might facilitate tumor growth by suppressing local antitumor immune responses.

Progesterone in pregnancy; receptor-ligand interaction and signaling pathways

Progesterone is indispensable in creating a suitable endometrial environment for implantation, and also for the maintenance of pregnancy. Successful pregnancy depends on an appropriate maternal immune response to the fetus. Along with its endocrine effects, progesterone also acts as an "immunosteroid", by contributing to the establishment of a pregnancy protective immune milieu. Progesterone plays a role in uterine homing of NK cells and upregulates HLA-G gene expression, the ligand for NK inhibitory and activating receptors. At high concentrations, progesterone is a potent inducer of Th2-type cytokines as well as of LIF and M-CSF production by T cells. A protein called progesterone-induced blocking factor (PIBF), by inducing a Th2-dominant cytokine production mediates the immunological effects of progesterone. PIBF binds to a novel type of the IL-4 receptor and signals via the Jak/STAT pathway, to induce a number of genes, that not only affect the immune response, but might also play a role in trophoblast invasiveness.

Progesterone-induced blocking factor (PIBF) modulates cytokine production by lymphocytes from women with recurrent miscarriage or preterm delivery

Spontaneous miscarriage and preterm delivery are common complications of pregnancy. Pro-inflammatory cytokines have been shown to be associated with recurrent spontaneous miscarriage (RSM) and preterm delivery (PTD) and these have led to exploration of ways to downregulate pro-inflammatory cytokines and/or to upregulate anti-inflammatory cytokines. Progesterone-induced blocking factor (PIBF) is a molecule with inhibitory effects on cell-mediated immune reactions. We have ascertained the effects of PIBF on secretion of selected type 1 and type 2 cytokines by peripheral blood mononuclear cells from healthy non-pregnant women, women undergoing normal pregnancy, women with unexplained RSM and women with PTD. Peripheral blood mononuclear cells from 30 women with a history of unexplained RSM, 18 women undergoing PTD, 11 women with normal pregnancy and 13 non-pregnant healthy women were stimulated with a mitogen in the absence and presence of PIBF after which the levels of cytokines released into culture supernatants were determined by ELISA. Production of the type 2 cytokines IL-4, IL-6 and IL-10 by lymphocytes from the RSM and PTD groups and of IL-4 and IL-10 by lymphocytes from healthy pregnant women was significantly increased upon exposure to PIBF, while the levels of type 1 cytokines were not affected. Ratios of type 1:type 2 cytokines were decreased, suggesting a shift towards Th2 bias. PIBF did not affect cytokine production by lymphocytes from non-pregnant women. Thus, PIBF acts on lymphocytes in pregnancy to induce a type 1 to type 2 cytokine shift by upregulating the production of type 2 cytokines.