Low pregnancy-specific beta-1-glycoprotein is associated with nondipper hypertension and increased risk of preeclampsia in pregnant women with newly diagnosed chronic hypertension.

Chronic hypertension is one of the major risk factors for preeclampsia. Pregnancy-specific beta-1-glycoprotein (PSG-1) is a protein that plays a critical role in fetomaternal immune modulation and has been shown to be closely associated with pregnancy adverse events such as preeclampsia. It is also known that PSG-1 and its source placenta are associated with many molecular pathways associated with blood pressure regulation. In addition, the nondipping pattern (NDP) of chronic hypertension has been shown to be an independent risk factor for preeclampsia. Dipper individuals experience a notable nighttime drop in blood pressure, typically around 10% or more compared to daytime levels, while nondipper individuals show a smaller nighttime blood pressure decrease, indicating potential circadian blood pressure regulation disruption. In this context, we aimed to reveal the relationship between PSG-1, NDP and preeclampsia in this study. A total of 304 pregnant women who were newly diagnosed in the first trimester and started on antihypertensive medication were included in this study. All subjects performed 24-h ambulatory blood pressure monitoring twice throughout pregnancy, the first in the 1. trimester to confirm the diagnosis of hypertension and the second between 20+0 and 21+1 gestational weeks to determine the dipper-nondipper status of hypertension. Subjects were grouped as dipper and nondipper according to blood pressure, and groups were compared in terms of PSG-1 levels. In this study, low PSG-1 levels and NDP were independently associated with preeclampsia. Findings from this study suggest that PSG-1 may play an important role in the causal relationship between NDP and preeclampsia.

Proteomic identification of biomarkers in maternal plasma that predict the outcome of rescue cerclage for cervical insufficiency.

OBJECTIVE: We sought to identify plasma protein biomarkers that are predictive of the outcome of rescue cerclage in patients with cervical insufficiency. METHODS: This retrospective cohort study included 39 singleton pregnant women undergoing rescue cerclage for cervical insufficiency (17-25 weeks) who gave plasma samples. Three sets of pooled plasma samples from controls (cerclage success, n = 10) and cases (cerclage failure, n = 10, defined as spontaneous preterm delivery at <33 weeks) were labeled with 6-plex tandem mass tag (TMT) reagents and analyzed by liquid chromatography-tandem mass spectrometry. Differentially expressed proteins between the two groups were selected from the TMT-based quantitative analysis. Multiple reaction monitoring-mass spectrometry (MRM-MS) analysis was further used to verify the candidate proteins of interest in patients with cervical insufficiency in the final cohort (n = 39). RESULTS: From MRM-MS analysis of the 40 proteins showing statistically significant changes (P < 0.05) from the TMT-based quantitative analysis, plasma IGFBP-2, PSG4, and PGLYRP2 levels were found to be significantly increased, whereas plasma MET and LXN levels were significantly decreased in women with cerclage failure. Of these, IGFBP-2, PSG4, and LXN levels in plasma were independent of cervical dilatation. A multiple-biomarker panel was developed for the prediction of cerclage failure, using a stepwise regression procedure, which included the plasma IGFBP-2, PSG4, and LXN (area under the curve [AUC] = 0.916). The AUC for this multiple-biomarker panel was significantly greater than the AUC for any single biomarker included in the multi-biomarker model. CONCLUSIONS: Proteomic analysis identified useful and independent plasma biomarkers (IGFBP-2, PSG4, and LXN; verified by MRM) that predict poor pregnancy outcome following rescue cerclage. Their combined analysis in a multi-biomarker panel significantly improved predictability.

Pro-angiogenic effects of pregnancy-specific glycoproteins in endothelial and extravillous trophoblast cells.

We previously reported that binding to heparan sulfate (HS) is required for the ability of the placentally secreted pregnancy-specific glycoprotein 1 (PSG1) to induce endothelial tubulogenesis. PSG1 is composed of four immunoglobulin-like domains but which domains of the protein bind to HS remains unknown. To analyze the interaction of PSG1 with HS, we generated several recombinant proteins, including the individual domains, chimeric proteins between two PSG1 domains, and mutants. Using flow cytometric and surface plasmon resonance studies, we determined that the B2 domain of PSG1 binds to HS and that the positively charged amino acids encompassed between amino acids 43-59 are required for this interaction. Furthermore, we showed that the B2 domain of PSG1 is required for the increase in the formation of tubes by endothelial cells (EC) including a human endometrial EC line and two extravillous trophoblast (EVT) cell lines and for the pro-angiogenic activity of PSG1 observed in an aortic ring assay. PSG1 enhanced the migration of ECs while it increased the expression of matrix metalloproteinase-2 in EVTs, indicating that the pro-angiogenic effect of PSG1 on these two cell types may be mediated by different mechanisms. Despite differences in amino acid sequence, we observed that all human PSGs bound to HS proteoglycans and confirmed that at least two other members of the family, PSG6 and PSG9, induce tube formation. These findings contribute to a better understanding of the pro-angiogenic activity of human PSGs and strongly suggest conservation of this function among all PSG family members.

Expression of Pregnancy Specific ß-1 Glycoprotein 1 in Cervical Cancer Cells.

BACKGROUND: Cervical Cancer (CC) is a worldwide public health concern associated with genetic alterations, among these the gain of the 19q chromosome harboring the Pregnancy Specific Glycoproteins (PSG) gene family. These proteins play a critical role in pregnancy, with participation in immunotolerance, angiogenesis, and invasion processes, which are also observed in carcinogenesis. The aim of this study was to determine the molecular alterations of PSG1 and its relationship with CC. METHODS: PSG1 Copy Number Variation (CNV) was evaluated in 31 CC and eight normal cervical tissues by qPCR. PSG1 expression was correlated with HPV detection and IL-10 and TGF-ß expression in CC samples. Finally, PSG1 protein expression was evaluated by immunofluorescence in CC cell lines, by immunohistochemistry in a tissue microarray, and by immunoblotting in the sera of women with normal cervix, pre-invasive lesions, and CC. RESULTS: PSG1 showed a gain of 25.6% in CNV and gene expression in CC. There was a lack of PSG1 expression in normal cervical epithelium and positive immunostaining in 57% of CC tissues, while all CC cell lines expressed PSG1. Finally, PSG1 was immunodetected in 90% of pre-invasive lesions and in all CC serum samples, but not in healthy women. PSG1 expression correlates with the expression of IL-10 and TGF-ß in CC tissues, but not with the presence of HPV. CONCLUSION: These data show evidence of the differential expression of PSG1 in CC that could explain its participation in tumor-biology and immunotolerance mechanisms. Further, its immunodetection could provide early detection of this cancer.

Trophoblast organoids as a model for maternal-fetal interactions during human placentation.

The placenta is the extraembryonic organ that supports the fetus during intrauterine life. Although placental dysfunction results in major disorders of pregnancy with immediate and lifelong consequences for the mother and child, our knowledge of the human placenta is limited owing to a lack of functional experimental models1. After implantation, the trophectoderm of the blastocyst rapidly proliferates and generates the trophoblast, the unique cell type of the placenta. In vivo, proliferative villous cytotrophoblast cells differentiate into two main sub-populations: syncytiotrophoblast, the multinucleated epithelium of the villi responsible for nutrient exchange and hormone production, and extravillous trophoblast cells, which anchor the placenta to the maternal decidua and transform the maternal spiral arteries2. Here we describe the generation of long-term, genetically stable organoid cultures of trophoblast that can differentiate into both syncytiotrophoblast and extravillous trophoblast. We used human leukocyte antigen (HLA) typing to confirm that the organoids were derived from the fetus, and verified their identities against four trophoblast-specific criteria3. The cultures organize into villous-like structures, and we detected the secretion of placental-specific peptides and hormones, including human chorionic gonadotropin (hCG), growth differentiation factor 15 (GDF15) and pregnancy-specific glycoprotein (PSG) by mass spectrometry. The organoids also differentiate into HLA-G+ extravillous trophoblast cells, which vigorously invade in three-dimensional cultures. Analysis of the methylome reveals that the organoids closely resemble normal first trimester placentas. This organoid model will be transformative for studying human placental development and for investigating trophoblast interactions with the local and systemic maternal environment.

Krüppel-Like Factor 10 participates in cervical cancer immunoediting through transcriptional regulation of Pregnancy-Specific Beta-1 Glycoproteins.

Cervical cancer (CC) is associated with alterations in immune system balance, which is primarily due to a shift from Th1 to Th2 and the unbalance of Th17/Treg cells. Using in silico DNA copy number analysis, we have demonstrated that ~20% of CC samples exhibit gain of 8q22.3 and 19q13.31; the regions of the genome that encodes the KLF10 and PSG genes, respectively. Gene expression studies demonstrated that there were no alterations in KLF10 mRNA expression, whilst the PSG2 and -5 genes were up-regulated by 1.76 and 3.97-fold respectively in CC compared to normal tissue controls. siRNA and ChIP experiments in SiHa cells have demonstrated that KLF10 participates in immune response through regulation of IL6, IL25 and PSG2 and PSG5 genes. Using cervical tissues from KLF10-/- mice, we have identified down-regulation of PSG17, -21 and -23 and IL11. These results suggest that KLF10 may regulate immune system response genes in cervical cancer among other functions. KLF10 and PSG copy number variations and alterations in mRNA expression levels could represent novel molecular markers in CC.

PSG9 promotes angiogenesis by stimulating VEGFA production and is associated with poor prognosis in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a common malignant solid tumor characterized by rich vascularization. Pregnancy-specific glycoprotein 9 (PSG9) is a member of the carcinoembryonic antigen (CEA)/PSG family and is produced at high levels during pregnancy. We previously identified PSG9 as an HCC-related protein. However, the expression of PSG9 and its regulation during HCC carcinogenesis remain poorly explored. In the present study, we first found that the levels of PSG9 protein were significantly increased in the plasma of HCC patients. PSG9 overexpression also increased the proliferation ability of an HCC cell line. High expression of PSG9 was associated with angiogenesis by accelerating VEGFA expression. In addition, Cox's proportional hazards model analysis revealed that the plasma level of PSG9 was an independent prognostic factor for overall survival. We propose that PSG9 is a novel indicator of prognosis in patients with HCC and could serve as a novel therapeutic target for HCC. Furthermore, our results indicate that PSG9 protein may facilitate the development of HCC by fostering angiogenesis via promoting VEGFA production in cancer cells.

Pregnancy-Specific ß1-Glycoproteins: Combined Biomarker Roles, Structure/Function Relationships and Implications for Drug Design.

BACKGROUND: Pregnancy specific ß1-glycoproteins (PSGs) have long been recognized as trophoblast quality and embryo viability markers. However, biological roles of PSGs remain obscure, and structure/function relationships to other feto-placental proteins as well as implications for drug design have not been reviewed. This review summarizes and discusses advances in 45-year studies of PSGs with focus on the latest achievements and the challenges for future investigations. METHODS: Literature search was performed to review the majority of recent PSG studies with emphasis on usage of high-throughput integrated proteomic profiling technologies, systems biology and bioinformatics approaches that enhance novel biomarker and drug target discovery as well as protein structure/activity analysis. RESULTS: Clinical significance and screening performance improved when PSG measurements were combined with those of other placenta-derived proteins: hCG, hPL, PAPP-A, and proMBP. Nevertheless, analysis of protein co-expression and co-localization data and the involvement of PSGs in protein interaction networks are being introduced to discover novel, specific and high-sensitive, gestational/cancer biomarkers. Despite biological roles of PSGs are not fully understood, there are evidences of that they exhibit immunomodulatory, antiinflammatory and proangiogenic effects. Investigation of structure/function relationships showed that PSGs may function in cooperative/coordinated manner with numerous regulatory proteins including alpha-fetoprotein and transforming growth factors-ß; this is provided by the presence of conserved short linear motifs (SLiMs) such as RGD, PXXP and AFP14-20-like (YXCX) ones. CONCLUSION: PSG-derived peptides may be used as a rationale to design novel drugs that mimic SLiMs involved in protein-protein interactions to inhibit domain-motif binding and to block cell signaling, and/or exert immunomodulatory, anti-inflammatory and proangiogenic effects.

Targeting PSG1 to enhance chemotherapeutic efficacy: new application for anti-coagulant the dicumarol.

Chemotherapeutic response is critical for the successful treatment and good prognosis in cancer patients. In this study, we analysed the gene expression profiles of preoperative samples from oestrogen receptor (ER)-negative breast cancer patients with different responses to taxane-anthracycline-based (TA-based) chemotherapy, and identified a group of genes that was predictive. Pregnancy specific beta-1-glycoprotein 1 (PSG1) played a central role within signalling pathways of these genes. Inhibiting PSG1 can effectively reduce chemoresistance via a transforming growth factor-ß (TGF-ß)-related pathway in ER-negative breast cancer cells. Drug screening then identified dicumarol (DCM) to target the PSG1 and inhibit chemoresistance to TA-based chemotherapy in vitro, in vivo, and in clinical samples. Taken together, this study highlights PSG1 as an important mediator of chemoresistance, whose effect could be diminished by DCM.

Pregnancy-specific glycoprotein 9 (PSG9), a driver for colorectal cancer, enhances angiogenesis via activation of SMAD4.

PSG9 is a member of the pregnancy-specific glycoprotein (PSG) family and has been shown to contribute to the progression of colorectal cancer (CRC) and cancer-related angiogenesis. Here, we aim to investigate abnormal PSG9 levels in patients with CRC and to emphasize the role of PSG9 in driving tumorigenesis. Serum from 140 patients with CRC and 125 healthy controls as well as 74 paired tumors and adjacent normal tissue were used to determine PSG9 levels. We discovered that PSG9 was significantly increased in serum (P<0.001) and in tumor tissues (P<0.001) from patients with CRC. Interestingly, the increased PSG9 levels correlated with poor survival (P=0.009) and microvessel density (MVD) (P=0.034). The overexpression of PSG9 strongly promoted the proliferation and migration of HCT-116 and HT-29 cells. However, PSG9 depletion inhibited the proliferation of SW-480 cells. Using a human umbilical vein endothelial cell tube-forming assay, we found that PSG9 promoted angiogenesis. The overexpression of PSG9 also increased the growth of tumor xenografts in nude mice. Co-immunoprecipitation experiments revealed that PSG9 was bound to SMAD4. The PSG9/SMAD4 complex recruited cytoplasmic SMAD2/3 to form a complex, which enhanced SMAD4 nuclear retention. The PSG9 and SMAD4 complex activated the expression of multiple angiogenesis-related genes (included IGFBP-3, PDGF-AA, GM-CSF, and VEGFA). Together, our findings illustrate the innovative mechanism by which PSG9 drives the progression of CRC and tumor angiogenesis. This occurs via nuclear translocation of PSG9/SMAD4, which activates angiogenic cytokines. Therefore, our study may provide evidence for novel treatment strategies by targeting PSG9 in antiangiogenic cancer therapy.

Induction and activation of latent transforming growth factor-ß1 are carried out by two distinct domains of pregnancy-specific glycoprotein 1 (PSG1).

Pregnancy-specific glycoproteins (PSGs) are a family of Ig-like proteins secreted by specialized placental cells. The PSG1 structure is composed of a single Ig variable region-like N-terminal domain and three Ig constant region-like domains termed A1, A2, and B2. Members of the human and murine PSG family have been shown to induce anti-inflammatory cytokines from monocytes and macrophages and to stimulate angiogenesis. We recently showed that recombinant forms of PSG1 (PSG1-Fc and PSG1-His) and PSG1 purified from the serum of pregnant women are associated with the immunoregulatory cytokine TGF-ß1 and activated latent TGF-ß1. Here, we sought to examine the requirement of specific PSG1 domains in the activation of latent TGF-ß1. Plasmon surface resonance studies showed that PSG1 directly bound to the small latent complex and to the latency-associated peptide of TGF-ß1 and that this binding was mediated through the B2 domain. Furthermore, the B2 domain alone was sufficient for activating the small latent complex. In separate experiments, we found that the PSG1-mediated induction of TGF-ß1 secretion in macrophages was dependent on the N-terminal domain. Mutagenesis analysis revealed that four amino acids (LYHY) of the CC' loop of the N-terminal domain were required for induction of latent TGF-ß1 secretion. Together, our results show that two distinct domains of PSG1 are involved in the regulation of TGF-ß1 and provide a mechanistic framework for how PSGs modulate the immunoregulatory environment at the maternal-fetal interface for successful pregnancy outcome.

Pregnancy-specific glycoprotein 1 (PSG1) activates TGF-ß and prevents dextran sodium sulfate (DSS)-induced colitis in mice.

Transforming growth factor-ßs (TGF-ßs) are secreted from cells as latent complexes and the activity of TGF-ßs is controlled predominantly through activation of these complexes. Tolerance to the fetal allograft is essential for pregnancy success; TGF-ß1 and TGF-ß2 play important roles in regulating these processes. Pregnancy-specific ß-glycoproteins (PSGs) are present in the maternal circulation at a high concentration throughout pregnancy and have been proposed to have anti-inflammatory functions. We found that recombinant and native PSG1 activate TGF-ß1 and TGF-ß2 in vitro. Consistent with these findings, administration of PSG1 protected mice from dextran sodium sulfate (DSS)-induced colitis, reduced the secretion of pro-inflammatory cytokines, and increased the number of T regulatory cells. The PSG1-mediated protection was greatly inhibited by the coadministration of neutralizing anti-TGF-ß antibody. Our results indicate that proteins secreted by the placenta directly contribute to the generation of active TGF-ß and identify PSG1 as one of the few known biological activators of TGF-ß2.

Circulating bovine pregnancy associated glycoproteins are associated with late embryonic/fetal survival but not ovulatory follicle size in suckled beef cows.

The objective was to examine the relationship between ovulatory follicle size and embryo and fetal survival by using circulating concentrations of bovine pregnancy associated glycoproteins (bPAG) to detect the presence of an embryo or fetus and monitor placental function. Before examining the relationship between bPAG, ovulatory follicle size, and embryo and fetal survival, the half-life of bPAG was determined in Exp. 1. The half-life of bPAG after PGF2α-induced abortion on d 32 to 36 postinsemination was 35.8 ± 21.9 h (mean ± SD; range 7.1 to 78.5 h). In Exp. 2, suckled beef cows (n = 91) were treated with the CO-Synch protocol (GnRH on d -9, PGF2α on d -2, and GnRH and AI 48 h later [d 0]) and classified into 1 of 2 ovulatory follicle size groups: 1) small follicle (<12.5 mm; n = 25) or 2) large follicle (≥ 12.5 mm; n = 66). The first increase (P < 0.0001) in serum bPAG occurred in pregnant cows on d 24 after insemination and circulating bPAG decreased before a decrease in progesterone in 3 of 4 cows that lost an embryo or fetus. Pattern of secretion of bPAG in serum from d 24 to 60 after insemination (d 0) was affected by day (P < 0.0001), but not ovulatory follicle size. In Exp. 3, suckled beef cows (n = 1164) were administered the CO-Synch protocol either with (donor cows; n = 810) or without (recipient cows; n = 354) AI on d 0. Single embryos (n = 394) or oocytes (n = 45) were recovered from the donor cows [d 7; embryo transfer (ET)] and all live embryos were transferred into recipients the same day. Cows were classified on d 0 as having a small (<12.5 mm) or large (≥ 12.5 mm) ovulatory follicle, and randomly chosen as donors or recipients to remove confounding effects of ovulatory follicle size on fertility. Serum concentration of bPAG at d 28 was not affected by ovulatory follicle size (P = 0.85), embryo stage at ET (P = 0.75), embryo quality at ET (P = 0.64), estradiol at GnRH2 (P = 0.62) or serum progesterone at ET (d7; P = 0.14). Compared with cows that maintained pregnancy (n = 176), cows that exhibited late embryonic or fetal mortality (n = 19) after d 28 had decreased (P < 0.05) concentrations of bPAG on d 28. In summary, there was no relationship between serum bPAG and ovulatory follicle size or embryo stage or quality at ET; however, cows that lost an embryo after d 28 had reduced concentrations of bPAG on d 28 compared with cows that maintained pregnancy.

Secretory/releasing proteome-based identification of plasma biomarkers in HBV-associated hepatocellular carcinoma.

For successful therapy, hepatocellular carcinoma (HCC) must be detected at an early stage. Herein, we used a proteomic approach to analyze the secretory/releasing proteome of HCC tissues to identify plasma biomarkers. Serum-free conditioned media (CM) were collected from primary cultures of cancerous tissues and surrounding noncancerous tissues. Proteomic analysis of the CM proteins permitted the identification of 1365 proteins. The enriched molecular functions and biological processes of the CM proteins, such as hydrolase activity and catabolic processes, were consistent with the liver being the most important metabolic organ. Moreover, 19% of the proteins were characterized as extracellular or membrane-bound. For validation, secretory proteins involved in transforming growth factor-ß signaling pathways were validated in plasma samples. Alphafetoprotein (AFP), metalloproteinase (MMP)1, osteopontin (OPN), and pregnancy-specific beta-1-glycoprotein (PSG)9 were significantly increased in HCC patients. The overall performance of MMP1 and OPN in the diagnosis of HCC remained greater than that of AFP. In addition, this study represents the first report of MMP1 as a biomarker with a higher sensitivity and specificity than AFP. Thus, this study provides a valuable resource of the HCC secretome with the potential to investigate serological biomarkers. MMP1 and OPN could be used as novel biomarkers for the early detection of HCC and to improve the sensitivity of biomarkers compared with AFP.

The role of pregnancy-specific glycoprotein 1a (PSG1a) in regulating the innate and adaptive immune response.

Among several explanations for the acceptance of the fetus, the one that suggests that the maternal immune system is suppressed or modified has been the subject of many studies. Thus, it has been proposed that the cells of innate immune system might be able to distinguish the pregnant from the non-pregnant state producing a signal, the so-called signal P. We have previously proposed that pregnancy-specific glycoprotein 1a (PSG1a), a representative member of the main glycoprotein family secreted by placental trophoblast, may modulate the activation of antigen-presenting cells promoting the T-cell shift of the maternal cell immunity toward a less harmful phenotype. In this review, we summarize current knowledge concerning the contribution of pregnancy-specific glycoprotein 1a (PSG1a) to modulate the maternal innate and adaptive immune response in order to assure a successful pregnancy.

PSG gene expression is up-regulated by lysine acetylation involving histone and nonhistone proteins.

BACKGROUND: Lysine acetylation is an important post-translational modification that plays a central role in eukaryotic transcriptional activation by modifying chromatin and transcription-related factors. Human pregnancy-specific glycoproteins (PSG) are the major secreted placental proteins expressed by the syncytiotrophoblast at the end of pregnancy and represent early markers of cytotrophoblast differentiation. Low PSG levels are associated with complicated pregnancies, thus highlighting the importance of studying the mechanisms that control their expression. Despite several transcription factors having been implicated as key regulators of PSG gene family expression; the role of protein acetylation has not been explored. METHODOLOGY/PRINCIPAL FINDINGS: Here, we explored the role of acetylation on PSG gene expression in the human placental-derived JEG-3 cell line. Pharmacological inhibition of histone deacetylases (HDACs) up-regulated PSG protein and mRNA expression levels, and augmented the amount of acetylated histone H3 associated with PSG 5'regulatory regions. Moreover, PSG5 promoter activation mediated by Sp1 and KLF6, via the core promoter element motif (CPE, -147/-140), was markedly enhanced in the presence of the HDAC inhibitor trichostatin A (TSA). This effect correlated with an increase in Sp1 acetylation and KLF6 nuclear localization as revealed by immunoprecipitation and subcellular fractionation assays. The co-activators PCAF, p300, and CBP enhanced Sp1-dependent PSG5 promoter activation through their histone acetylase (HAT) function. Instead, p300 and CBP acetyltransferase domain was dispensable for sustaining co-activation of PSG5 promoter by KLF6. CONCLUSIONS/SIGNIFICANCE: Results are consistent with a regulatory role of lysine acetylation on PSG expression through a relaxed chromatin state and an increase in the transcriptional activity of Sp1 and KLF6 following an augmented Sp1 acetylation and KLF6 nuclear localization.

Correlation between biological activity and conformational dynamics properties of tetra- and pentapeptides derived from fetoplacental proteins.

In this work, using molecular dynamics simulation, we study conformational and dynamic properties of biologically active penta- and tetrapeptides derived from fetoplacental proteins such as alpha-fetoprotein, pregnancy specific ß1-glycoprotein, and carcinoembryonic antigen. Existence of correlation between flexibility of peptide backbone and biological activity of the investigated peptides was shown. It was also demonstrated that flexibility of peptide backbone depends not only on its length, but also on the presence of reactive functional groups in amino acid side chains that participate in intramolecular interactions. Peptides that demonstrate similar biological effects in regulation of proliferation of lymphocytes and expression of differentiation antigens on their surface (LDSYQCT, PYECE, YECE, and YVCE) are characterized by rigidity of their peptide backbone. Increased backbone flexibility in peptides PYQCE, YQCE, SYKCE, YQCT, YQCS, YVCS, YACS, and YACE is correlated with decreased biological activity. Conformational mobility of amino acid residues does not depend on physicochemical properties only, but also on intramolecular interactions. So, evolutionary restrictions should exist to maintain such interactions in the environment of functionally important sites.

Expression and localization of DLX3, PPARG and SP1 in bovine trophoblast during binucleated cell differentiation.

The differentiation of the trophoblast is marked in ruminants by the formation of binucleated cells (BNC). They appear from pre-implantation onwards but the molecular mechanisms underlying their differentiation remain largely unexplored. Taking advantage of our recent data, we analyzed the expression pattern of DLX3 and PPARG that are known regulators of early placenta formation and extended our analysis to one of their potential regulators, SP1. Our study is the first to demonstrate the co-expression of DLX3, PPARG and SP1 in bovine BNC nuclei. This suggests a possible role of these transcription factors through BNC specific genes at the time of pre-placental differentiation.

Human pregnancy specific beta-1-glycoprotein 1 (PSG1) has a potential role in placental vascular morphogenesis.

Previous studies suggest that human pregnancy specific beta-1-glycoproteins (PSGs) play immunomodulatory roles during pregnancy; however, other possible functions of PSGs have yet to be explored. We have observed that PSGs induce transforming growth factor beta 1 (TGFB1), which among its other diverse functions inhibits T-cell function and has proangiogenic properties. The present study investigates a potential role for PSG1, the most abundant PSG in maternal serum, as a possible inducer of proangiogenic growth factors known to play an important role in establishment of the vasculature at the maternal-fetal interface. To this end, we measured TGFB1, vascular endothelial growth factors (VEGFs) A and C, and placental growth factor (PGF) protein levels in several cell types after PSG1 treatment. In addition, tube formation and wound healing assays were performed to investigate a possible direct interaction between PSG1 and endothelial cells. PSG1 induced up-regulation of both TGFB1 and VEGFA in human monocytes, macrophages, and two human extravillous trophoblast cell lines. We did not observe induction of VEGFC or PGF by PSG1 in any of the cells tested. PSG1 treatment resulted in endothelial tube formation in the presence and absence of VEGFA. Site-directed mutagenesis was performed to map the essential regions within the N-domain of PSG1 required for functional activity. We found that the aspartic acid at position 95, previously believed to be required for binding of PSGs to cells, is not required for PSG1 activity but that the amino acids implicated in the formation of a salt bridge within the N-domain are essential for PSG1 function.