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The placenta is the interface between the fetal and maternal environments during mammalian gestation, critically safeguarding the health of the developing fetus and the mother. Placental trophoblasts origin from embryonic trophectoderm that differentiates into various trophoblastic subtypes through villous and extravillous pathways. The trophoblasts actively interact with multiple decidual cells and immune cells at the maternal-fetal interface and thus construct fundamental functional units, which are responsible for blood perfusion, maternal-fetal material exchange, placental endocrine, immune tolerance, and adequate defense barrier against pathogen infection. Various pregnant complications are tightly associated with the defects in placental development and function maintenance. In this review, we summarize the current views and our recent progress on the mechanisms underlying the formation of placental functional units, the interactions among trophoblasts and various uterine cells, as well as the placental barrier against pathogen infections during pregnancy. The involvement of placental dysregulation in adverse pregnancy outcomes is discussed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Depletion of hepatocyte growth factor (HGF) or mesenchymal-epithelial transition factor (c-Met) in mice leads to fetal lethality and placental maldevelopment. However, the dynamic change pattern of HGF/c-Met signaling during placental development and its involvement in the early differentiation of trophoblasts remain to be elucidated. In this study, using in situ hybridization assay, we elaborately demonstrated the spatial-temporal expression of Hgf and c-Met in mouse placenta from E5.5, the very early stage after embryonic implantation, to E12.5, when the placental structure is well developed. The concentration of the soluble form of c-Met (sMet) in maternal circulation peaked at E10.5. By utilizing the induced differentiation model of mouse trophoblast stem cells (mTSCs), we found that HGF significantly promoted mTSC differentiation into syncytiotrophoblasts (STBs) and invasive parietal trophoblast giant cells (PTGCs). Interestingly, sMet efficiently reversed the effect of HGF on mTSC differentiation. These findings indicate that HGF/c-Met signaling participates in regulating placental trophoblast cell fate at the early differentiation stage and that sMet acts as an endogenous antagonist in this aspect.

MicroRNA (miR)-210 is a well-known hypoxia-inducible small RNA. Increasing in vitro evidence demonstrates its involvement in regulating multiple behaviors of placental trophoblasts. However, direct in vivo evidence remains lacking. In the present study, we generated a miR-210-deficient mouse strain using CRISPR/Cas9 technology, in which miR-210 expression was markedly deficient in various tissues. Little influence on fertility rate and litter size was observed after the deletion of miR-210 in mice. Continuous exposure of pregnant mice to hypoxia (10.5% O2) from E6.5 to E10.5 or to E18.5 led to reduction in fetal weight, and such fetal weight loss was markedly worsened in miR-210-knockout dams. Analysis of the placental structure demonstrated the reduced expansion of placental spongiotrophoblast layer and hampered development of labyrinth fetal blood vessels in knockout mice compared to the wild-type controls upon hypoxia stimulation. The findings indicate that miR-210 participates in regulating placental adaptation to hypoxic stress during pregnancy., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Physical Therapy Association. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objectives: During human pregnancy, the endothelial cells of the uterine spiral arteries (SPA) are extensively replaced by a subtype of placental trophoblasts, endovascular extravillous trophoblasts (enEVTs), thus establishing a placental-maternal circulation. On this pathway, foetus-derived placental villi and enEVTs bath into the maternal blood that perfuses along SPA being not attacked by the maternal lymphocytes. We aimed to reveal the underlying mechanism of such immune tolerance., Methods: In situ hybridization, immunofluorescence, ELISA and FCM assay were performed to examine TGF-β1 expression and distribution of regulatory T cells (Tregs) along the placental-maternal circulation route. The primary enEVTs, interstitial extravillous trophoblasts (iEVTs) and decidual endothelial cells (dECs) were purified by FACS, and their conditioned media were collected to treat naïve CD4 + T cells. Treg differentiation was measured by FLOW and CFSE assays., Results: We found that enEVTs but not iEVTs or dECs actively produced TGF-β1. The primary enEVTs significantly promoted naïve CD4 + T-cell differentiation into immunosuppressive FOXP3 + Tregs, and this effect was dependent on TGF-β1. In recurrent spontaneous abortion (RSA) patients, an evidently reduced proportion of TGF-β1-producing enEVTs and their ability to educate Tregs differentiation were observed., Conclusions: Our findings demonstrate a unique immune-regulatory characteristic of placental enEVTs to develop immune tolerance along the placental-maternal circulation. New insights into the pathogenesis of RSA are also suggested., (© 2020 The Authors. Cell Proliferation Published by John Wiley & Sons Ltd.)

The pregnancy complication preeclampsia is directly associated with hypoxic stress and insufficient trophoblast cell differentiation. The hypoxia-inducible microRNA (miRNA), miR-210, has been identified as a significantly up-regulated miRNA in preeclamptic placenta, and evidence in other cell types has indicated a feedback regulation between miR-210 and hypoxia-inducible factor-1α (HIF-1α) under hypoxic condition. It remains unclear whether and how the feedback loop between miR-210 and HIF-1α may contribute to trophoblast dysfunction in preeclampsia. Here, we proved that cytoplasmic polyadenylation element-binding 2 (CPEB2) was a direct target of miR-210 in human trophoblast. CPEB2 could inhibit the translation of hypoxia-induced HIF-1α via directly binding the cytoplasmic polyadenylation element (CPE) site in the 3'-untranslated region (UTR) of HIF-1α mRNA. The increase in the HIF-1α level upon hypoxia treatment could be efficiently reversed by miR-210 inhibitor. In addition, CPEB2 was primarily expressed in villous syncytiotrophoblasts, and the suppression of trophoblast cell syncytialization by miR-210 could be significantly rescued by CPEB2 overexpression. In preeclamptic placenta, the expression of CPEB2 was evidently lower than normal pregnant control, and the miR-210 level was aberrantly higher and trophoblast syncytialization was limited. The findings revealed a positive feedback loop between miR-210 and HIF-1α that is mediated by CPEB2 in human trophoblasts, and demonstrated a mechanism underlying the insufficient trophoblast syncytialization in preeclampsia under hypoxic stress., (© The Author(s) 2019. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Placenta serves as a temporary fetal organ, which mediates maternal-fetal crosstalk and intrauterine fetal growth. Placental defensive barrier is a fundamental physiological function, which balances maternal immune tolerance to the fetus and resistance to pathogens. This review summarizes the latest research progress on the mechanisms of placental barrier formation from the view of placental development. Recent discoveries have shed light on the cellular and molecular properties of placental defensive mechanisms in syncytiotrophoblast, including autophagy, exosome mediated anti-pathogenic pathways, cell-cell junctions and cytoskeleton networks. We also present an overview of placental barrier dysfunction and its implications in intrauterine TORCH infections.

Preeclampsia (PE) is the leading cause of maternal and neonatal morbidity and mortality. Defects in trophoblast invasion, differentiation of endovascular extravillous trophoblasts (enEVTs), and spiral artery remodeling are key factors in PE development. There are no markers clinically available to predict PE, leaving expedited delivery as the only effective therapy. Dysregulation of miRNA in clinical tissues and maternal circulation have opened a new avenue for biomarker discovery. In this study, we investigated the role of miR-218-5p in PE development. miR-218-5p was highly expressed in EVTs and significantly downregulated in PE placentas. Using first-trimester trophoblast cell lines and human placental explants, we found that miR-218-5p overexpression promoted, whereas anti-miR-218-5p suppressed, trophoblast invasion, EVT outgrowth, and enEVT differentiation. Furthermore, miR-218-5p accelerated spiral artery remodeling in a decidua-placenta co-culture. The effect of miR-218-5p was mediated by the suppression of transforming growth factor (TGF)-β2 signaling. Silencing of TGFB2 mimicked, whereas treatment with TGF-β2 partially reversed, the effects of miR-218-5p. Taken together, these findings demonstrate that miR-218-5p promotes trophoblast invasion and enEVT differentiation through a novel miR-218-5p-TGF-β2 pathway. This study elucidates the role of an miRNA in enEVT differentiation and spiral artery remodeling and suggests that downregulation of miR-218-5p contributes to PE development., (Copyright © 2018 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)

Preeclampsia is a severe pregnancy-related disorder, and patients usually present with high circulating inflammatory factor levels and excessive activation of the nuclear factor-κB (NF-κB) pathway. Administration of aspirin (ASP) is effective for preventing preeclampsia, and thus, we propose that ASP might affect placental function by regulating the NF-κB pathway. Systemic lipopolysaccharide (LPS) (20 μg/kg) was used to induce preeclampsia-like pregnant mouse model, and low-dose ASP (15.2 mg/kg) was administrated. Here, we report significantly increased circulatory expression levels of the proinflammatory cytokines tumor necrosis factor-alpha, interleukin-6, and soluble Fms-related tyrosine kinase-1 in LPS-treated pregnant mice, accompanied by kidney and placental dysfunction. Low-dose ASP treatment significantly reversed the preeclampsia-like phenotype, lowering hypertension, decreasing proteinuria, and ameliorating fetal growth retardation. Moreover, the excessive activation of NF-κB signaling in mice placentae induced by LPS was significantly reduced by ASP. In JEG-3 cells, LPS activated the NF-κB signaling pathway by upregulating the expression of cyclooxygenase-2 (COX-2) and related inflammatory factors, whereas the invasion ability of JEG-3 cells was weakened. However, ASP administration impeded NF-κB signaling activation, downregulated COX-2 and inflammatory factor expression, and rescued trophoblast invasion. This study provides new evidence that low-dose ASP is beneficial for preeclampsia prevention by inhibiting NF-κB and its downstream signaling pathways in trophoblast cells.

Proper differentiation of trophoblast cells in the human placenta is a prerequisite for a successful pregnancy, and dysregulation of this process may lead to malignant pregnancy outcomes, such as preeclampsia. Finding specific markers for different types of trophoblast cells is essential for understanding trophoblast differentiation. Here, we report that placenta-specific protein 8 (PLAC8) is specifically expressed in the interstitial extravillous trophoblast cells (iEVTs) on the fetomaternal interface. Using model systems, including placental villi-decidua co-culture, iEVTs induction by using primary trophoblast cells or explants, etc., we found that PLAC8 promotes invasion and migration of iEVTs. Mechanistically, time-lapse imaging, GTPase activity assay, co-immunoprecipitation and RNA-seq studies show that PLAC8 increases the Cdc42 and Rac1 activities, and further induces the formation of filopodia at the leading edge of the migratory trophoblast cells. More interestingly, PLAC8 is significantly upregulated under hypoxia and expression of PLAC8 is higher in iEVTs from preeclamptic placentas when compared with those from the normal control placentas. Together, PLAC8 is a new marker for iEVTs and plays an important role in promoting trophoblast invasion and migration., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2018. Published by The Company of Biologists Ltd.)

Objective: Preeclampsia is a pregnancy-related syndrome. Shallow invasion of uterine wall by trophoblast cells has been generally accepted as the major pathological change of this disorder. We previously found downregulation of miR-195 in preeclamptic placentas. Bioinformatic analysis predicted a type II activin receptor, activin receptor type-2B (ActRIIB), as one of the potential targets of miR-195. Considering the key function of activin A on trophoblast cell behaviors and placenta development, we proposed miR-195 may affect trophoblast cell invasion by repressing the expression of ActRIIB., Methods: The colocalization of ActRIIB and miR-195 in human placenta was measured by in-situ hybridization and immunohistochemistry. Western blotting, real-time PCR and dual luciferase assay were performed in human trophoblast cell line, HTR8/SVneo cells, to validate the targeting of ActRIIB by miR-195. Cell invasiveness was analyzed using transwell insert invasion assay in HTR8/SVneo cells., Results: In human placenta, ActRIIB and miR-195 exhibited similar localization in various subtypes of trophoblast cells, including villous and extravillous trophoblasts. The protein expressions of ActRIIB in preeclamptic placenta were significantly higher as compared with the normal controls, which was opposite to the changing pattern of miR-195. In HTR8/SVneo cells, miR-195 could directly target and suppress the expression of ActRIIB. Meanwhile, the invasion-promoting effect of miR-195 on trophoblast cells could be largely impeded by ActRIIB overexpression., Conclusion: In human trophoblast cells, miR-195 could promote cell invasion via directly targeting ActRIIB. The impaired miR-195 expression may contribute to the occurrence or development of preeclampsia through interfering with activin/nodal signaling in the placenta.

Context: Matrix Metalloproteinase-26 (MMP-26) is the smallest member of matrix metalloproteinase (MMP) family that functions mainly in the extracellular milieu to cleave the extracellular matrix proteins. It is expressed in various cell types of placenta, but its function in placentation has been poorly understood. Considering the existence of a unique cysteine switch sequence in MMP-26 protein sequence, as well as the evidence in cancer cells indicating the digestion of the NH2-terminal domain of ERβ by MMP-26, we hypothesize that MMP-26 may have specific intracellular activity in human placental trophoblast cells., Objective: This study aimed to identify the intracellular binding partners of MMP-26 and investigate how MMP-26 is involved in placentation through the interactions with its partners., Setting and Design: Yeast two-hybrid system was employed to screen potential binding partners of MMP-26 in human placenta. Immunoprecipitation and immunofluorescence assays were conducted to verify the interactions between MMP-26 and the binding partners. HEK293T and HTR8/SVneo cell lines were used as in vitro models to investigate the roles of the interaction between MMP-26 and its binding partner on cell behaviors., Results: RESULTS of yeast two-hybrid assay, immunoprecipitation, and immunofluorescence assays revealed that MMP-26 could bind to growth differentiation factor 15 (GDF15) in the intracellular milieu. The binding of MMP-26 to GDF15 was responsible for the processing and maturation of pro-GDF15, and the process was dependent on the enzymatic activity of MMP-26. In human placental trophoblast cells, MMP-26 could facilitate the pro-apoptotic effect of GDF15., Conclusions: This is the first report to demonstrate the physiological function of placental MMP-26 in processing GDF15 and subsequently promoting trophoblast cell apoptosis. These findings expand our understanding of the working mechanism of the metalloproteinase in the process of placentation.

Preeclampsia is a major cause of maternal and fetal mortality and morbidity worldwide. The differential expression of several microRNAs (miRNAs) has been found in preeclamptic placentas. However, great conflict exists regarding this aspect, and detailed examinations have largely been lacking of miRNA profiles in different parts of the placenta and in maternal plasma of women with this disorder. In this study, a total of 9 downregulated miRNAs (miR-195, miR-223, miR-218, miR-17, miR-18a, miR-19b1, miR-92a1, miR-379, and miR-411) and 7 upregulated miRNAs (miR-210, miR-30a-3p, miR-518b, miR-524, miR-17-3p, miR-151, and miR-193b) were identified in severe preeclampsia (sPE) placentas when compared with normal pregnant controls. In addition, sampling position in the chorionic or basal plate of placenta led to evident variations in differential miRNAs of sPE placentas. In a prospective pregnant cohort, we found that the circulating levels of 3 members of miR-17-92 cluster (ie, miR-18a, miR-19b1, and miR-92a1) were significantly lower, whereas that of miR-210 was higher in sPE patients than those in normal controls at gestational weeks 15 to 18 and at term. The results of in situ hybridization revealed the localization of miR-18a, miR-92a1, and miR-210 in various subtypes of placental trophoblasts and endothelial cells. In human trophoblast cell line, HTR8/SVneo cells, miR-18a could promote trophoblast cell invasion via targeting and suppressing Smad2 expression. This study provides fundamental evidences for exploring the roles of miRNAs in the pathogenesis of preeclampsia.

Context: The pregnancy-specific disorder preeclampsia is a major cause of maternal mortality and morbidity. Activin A has been suggested as a potential biomarker of the disease, but whether it plays a role in the pathology of preeclampsia or is just a manifestation of the disease is not fully understood., Objective: The objective of the study was to examine the roles of Activin A on placental trophoblast cells under pathological conditions of preeclampsia., Design: Placental and plasma productions of Activin A in healthy pregnant women and preeclamptic patients were compared by using clinical samples obtained from Peking University First Hospital during November 2005 to November 2007. The role of Activin A at pathological doses was investigated in human trophoblast cells., Results: Plasma and placental productions of Activin A were significantly higher in preeclamptic patients when compared with normal pregnant subjects in a Chinese Han population. Treatment of trophoblast cells with high doses of Activin A resulted in a significant increase in cell apoptosis. This effect was blocked not only by silencing Activin A's receptor activin receptor-like kinase 4 but also by knockdown of Nodal's receptor ALK7. Important to note was that Activin A could significantly increase Nodal expression in trophoblast cells, and knockdown of Nodal resulted in evident blockage on Activin A-induced trophoblast cell apoptosis., Conclusion: High levels of Activin A observed in preeclamptic placenta may play a role in the pathogenesis of preeclampsia by inducing excessive apoptosis in placenta indirectly through enhancing Nodal expression.

Preeclampsia is a pregnancy-specific syndrome mainly characterized by hypertensive disorder and proteinuria after gestational weeks 20. So far the etiology of preeclampsia remains unclear. We previously reported that preeclamptic placentas exhibited decreased mRNA expression and hypermethylation in promoter region of the paternally imprinted H19 gene compared with normal placentas. H19 has recently been identified to encode the precursor of miR-675, indicating a possible novel functional pathway of the imprinting gene. The aim of the present study was to identify the roles of H19 gene via miR-675 pathway in human trophoblast cells, and to figure out the involvement of this pathway in pathogenesis of preeclampsia. Knockdown of H19 gene or inhibition of miR-675 exhibited similar proliferation-promoting effect in human trophoblastic JEG-3 cells. Target gene prediction in combination with luciferase assay revealed that miR-675 could directly downregulate Nodal Modulator 1 (NOMO1) protein expression by binding to 3'-UTR sequence of NOMO1. Overexpression of NOMO1 in JEG-3 cells could rescue miR-675-surppressed cell proliferation and phosphorylation of Smad2, while Nodal had additive effect with miR-675 in suppression cell proliferation and activation of Smad2. In early-onset preeclamptic placentas, expression levels of H19 gene and miR-675 were appreciably lower, while NOMO1 protein level was higher than those in normal placentas. Taken together, our data suggested that H19 gene could inhibit human trophoblast cell proliferation via encoding miR-675 that targeted NOMO1, and aberrantly lowered expression of H19 in placenta may participate in the excessive proliferation of trophoblast cells observed in early-onset severe preeclampsia by downregulating miR-675 which targets NOMO1 and interferes with Nodal signaling.

Background: Preeclampsia (PE) is a pregnancy-specific syndrome manifested by on-set of hypertension and proteinuria after 20 weeks of gestation. Abnormal placenta development has been generally accepted as initial cause of the disorder. Recently, miR-195 was found to be down-regulated in preeclamptic placentas compared with normal pregnant ones, indicating possible association of this small molecule with placental pathology of preeclampsia. By far the function of miR-195 in the development of placenta remains unknown., Methodology/principal Findings: Bioinformatic assay predicted ActRIIA as one of the targets for miR-195. By using Real-time PCR, Western blotting and Dual Luciferase Assay, we validated that ActRIIA was the direct target of miR-195 in human trophoblast cells. Transwell insert invasion assay showed that miR-195 could promote cell invasion in trophoblast cell line, HTR8/SVneo cells, and the effect could be abrogated by overexpressed ActRIIA. In preeclamptic placenta tissues, pri-miR-195 and mature miR-195 expressions were down-regulated, whereas ActRIIA level appeared to be increased when compared with that in gestational-week-matched normal placentas., Conclusions/significance: This is the first report on the function of miR-195 in human placental trophoblast cells which reveals an invasion-promoting effect of the small RNA via repressing ActRIIA. Aberrant expression of miR-195 may contribute to the occurrence of preeclampsia through interfering with Activin/Nodal signaling mediated by ActRIIA in human placenta.

Preeclampsia (PE) is a severe hypertensive disorder associated with pregnancy; despite substantial research effort in the past several years, the etiology of PE is still unclear. The role of epigenetic factors in the etiology of PE, including DNA methylation, has been poorly characterized. In the present study, we investigated global DNA methylation as well as DNA methylation of the paternally imprinted H19 gene in preeclamptic placentas. Using 5-methylcytosine immunohistochemistry and Alu and LINE-1 repeat pyrosequencing, we found that the global DNA methylation level and the DNA (cytosine-5) methyltransferase 1 mRNA level were significantly higher in the early-onset preeclamptic placentas when compared with the normal controls. Data from methylation-sensitive high resolution melting demonstrated hypermethylation of the promoter region of the H19 gene, and results of real-time PCR showed decreased mRNA expression of H19 gene in the early-onset preeclamptic placentas as compared with the normal controls. Our results suggest that abnormal DNA methylation during placentation might be involved in the pathophysiology of PE, especially early-onset preeclampsia.

SWAP-70 has been demonstrated as a multiple functional signaling protein involved in formation of membrane ruffling induced by signal cascade of tyrosine kinase growth factor receptors. In the present study, the spatial and temporal expression pattern of SWAP-70 on human fetomaternal interface was investigated using specimens collected from tubal and normal pregnancies by in situ hybridization, immunohistochemistry, and Western blotting. Data showed an intense expression of SWAP-70 in trophoblasts at weeks 3-6 of fallopian implantation and at weeks 6-7 of normal pregnancy. The most intense expression was exhibited by those highly motile and invasive extravillous trophoblasts. From gestational week 8 on, the level of SWAP-70 in trophoblasts decreased significantly, and the signal was restricted in villous cytotrophoblast cells. In the in vitro cultured human trophoblast cell line, B6Tert-1, colocalization of SWAP-70 with F-actin was verified. Data in human placenta were similar to what we recently reported on rhesus monkey fetomaternal interface. Our results suggest that SWAP-70 may be involved in regulating migration and invasion of trophoblast cells during the processes of embryonic implantation and placentation in primates.

SWAP-70 is a unique signaling protein involved in multiple processes including lymphatic cell activation, migration, adhesion, and cytoskeleton organization. Its role in reproductive system remains to be unclear. In the present study, the spatial and temporal expression of SWAP-70 in the uterus during normal menstrual cycle as well as on the feto-maternal interface during pregnancy was investigated in the rhesus monkey by in situ hybridization and immunohistochemistry. It was shown that SWAP-70 was mainly expressed in glandular epithelial cells of uterine endometrium, and the level peaked at the mid-secretory stage. At the beginning of embryonic implantation, SWAP-70 was intensely expressed at the implantation site, mainly localized in glandular and luminal epithelial cells, as well as in primary trophoblasts and epithelial plaque. High level of SWAP-70 was observed in villous cytotrophoblast (VCT), syncytiotrophoblast (ST), column cytotrophoblast, trophoblast shell, interstitial trophoblast, and endovascular trophoblast during gestational days 15-25. From gestational day 50 to term, expression of SWAP-70 decreased evidently and was restricted in VCT cells. What's more, SWAP-70 co-localized with F-actin on the feto-maternal interface, especially in highly motive extravillous trophoblasts. The data indicate that SWAP-70 may be involved in regulating motility of trophoblast cells during embryonic implantation and placentation.

Objective: To study the expression of extracellular matrix metalloproteinase inducer (EMMPRIN) in preeclampsia placenta and the relation with preeclampsia attacks., Methods: Forty-four samples from pregnant women with preeclampsia (preeclampsia group), 38 samples from pregnant women with eclampsia, and 49 samples from normal pregnancies (control group) were obtained. We detected the expression of EMMPRIN in placenta by immunohistochemistry and the expression of EMMPRIN mRNA by RT-PCR., Results: (1) EMMPRIN positive expression: in preeclampsia group, the moderate expression rate was 18% (8/44) and the strong positive rate was 9% (4/44); in eclampsia group moderate positive rate was 21% (8/38) and strong positive rate 13% (5/38). The difference of the two groups was insignificant (P > 0.05). In control group the moderate positive rate was 12% (6/49) and strong positive rate 82% (40/49), the difference from the preeclampsia and the eclampsia groups was significant (P < 0.001). (2) EMMPRIN mRNA expression: in preeclampsia group EMMPRIN mRNA expression in term placenta (37 - 40 gestational weeks) was 0.342 +/- 0.002, and in eclampsia group 0.344 +/- 0.023; the difference between the two groups was insignificant (P > 0.05). In control group EMMPRIN mRNA expression in term placenta (37 - 40 gestational weeks) was 0.872 +/- 0.094, the differences between the control group and preeclampsia and eclampsia groups were both significant (P < 0.001)., Conclusion: The decrease in the expression of EMMPRIN in placenta is an important cause of preeclampsia onset; expression rate of EMMPRIN may serve as an indicator in predicting preeclampsia.

Steroidogenesis in the placenta has been studied widely, but little is known about steroid metabolism in ectopic pregnancy. Previous studies have indicated that trophoblast invasion and placentation in the uterus and the fallopian tube may be controlled by similar mechanisms. As far as 17beta-estradiol (E(2)) production is concerned, it has been well demonstrated that its biosynthesis in the placenta involves the action of P450 aromatase (P450arom) and 17beta-hydroxysteroid dehydrogenase type 1 (17HSD1). The purpose of this study was to characterize the expression pattern of P450arom and 17HSD1 at the fetal-maternal interface, particularly in various trophoblast cells, in tubal pregnancy. Using in situ hybridization, P450arom mRNA was localized in syncytiotrophoblast (ST) cells, which are mainly responsible for hormone production during pregnancy, whereas no signal was detected in villous cytotrophoblast (VCT), column CT and extravillous CT (EVCT) cells. Immunohistochemical assays revealed that 17HSD1 is present in ST cells, a large portion of EVCT cells and 20% of column CT cells. On the other hand, no expression of 17HSD1 was detected in VCT cells. In addition, 17HSD1 was found in epithelial cells of the fallopian tube. Interestingly, the expression level of 17HSD1 in fallopian tube epithelium during tubal pregnancy was significantly higher than that during normal cycle. Our data provide the first evidence that normal and tubal pregnancies possess identical expression of P450arom and 17HSD1 in ST cells and therefore, similar E(2) production in the placenta. Further, the association of 17HSD1 with EVCT cells indicates that 17HSD1 perhaps play a role in trophoblast invasion. Finally, increased expression of 17HSD1 in epithelial cells of fallopian tube may lead to a local E(2) supply sufficient for the maintenance of tubal pregnancy.

Uterine spiral artery remodeling is the prerequisite for ensuring adequate blood supply to the maternal-fetal interface during human pregnancy. One crucial cellular event in this process involves the extensive replacement of the spiral artery endothelial cells by endovascular extravillous trophoblasts (enEVTs), a subtype of extravillous trophoblasts (EVTs). However, our understanding of the properties of enEVTs remains limited. Human enEVTs in decidual tissues during early pregnancy was purified using flow sorting by specific makers, NCAM1 and HLA-G. The high-throughput RNA sequencing analysis as well as the cytokine antibody array experiments were carried out to analyze for cell properties. Gene ontology (GO) enrichment, kyoto encyclopedia of genes and genomes (KEGG) enrichment, and gene set enrichment analysis (GSEA) were performed on differentially expressed genes of enEVTs. Immunofluorescent assays were used to verify the analysis results. Both enEVTs and interstitial EVTs (iEVTs) exhibited gene expression patterns typifying EVT characteristics. Intriguingly, enEVTs displayed gene expression associated with immune responses, particularly reminiscent of M2 macrophage characteristics. The active secretion of multiple cytokines and chemokines by enEVTs provided partial validation for their expression pattern of immune-regulatory genes. Our study reveals the immune-regulatory properties of human enEVTs and provides new insights into their functions and mechanisms involved in spiral artery remodeling. • Human enEVTs are purified using NCAM1 and HLA-G through flow sorting. • enEVTs can be distinguished from iEVTs at specific transcriptomic patterns. • enEVTs display some specific immune-regulatory characteristics. [ABSTRACT FROM AUTHOR]

Maintaining placental endocrine homeostasis is crucial for a successful pregnancy. Pre‐eclampsia (PE), a gestational complication, is a leading cause of maternal and perinatal morbidity and mortality. Aberrant elevation of testosterone (T0) synthesis, reduced estradiol (E2), and melatonin productions have been identified in preeclamptic placentas. However, the precise contribution of disrupted homeostasis among these hormones to the occurrence of PE remains unknown. In this study, we established a strong correlation between suppressed melatonin production and decreased E2 as well as elevated T0 synthesis in PE placentas. Administration of the T0 analog testosterone propionate (TP; 2 mg/kg/day) to pregnant mice from E7.5 onwards resulted in PE‐like symptoms, along with elevated T0 production and reduced E2 and melatonin production. Notably, supplementation with melatonin (10 mg/kg/day) in TP‐treated mice had detrimental effects on fetal and placental development and compromised hormone synthesis. Importantly, E2, but not T0, actively enhanced melatonin synthetase AANAT expression and melatonin production in primary human trophoblast (PHT) cells through GPER1‐PKA‐CREB signaling pathway. On the other hand, melatonin suppressed the level of estrogen synthetase aromatase while promoting the expressions of androgen synthetic enzymes including 17β‐HSD3 and 3β‐HSD1 in PHT cells. These findings reveal an orchestrated feedback mechanism that maintains homeostasis of placental sex hormones and melatonin. It is implied that abnormal elevation of T0 synthesis likely serves as the primary cause of placental endocrine disturbances associated with PE. The suppression of melatonin may represent an adaptive strategy to correct the imbalance in sex hormone levels within preeclamptic placentas. The findings of this study offer novel evidence that identifies potential targets for the development of innovative therapeutic strategies for PE. [ABSTRACT FROM AUTHOR]

Objectives: Success in pregnancy in mammals predominantly depends on a well‐developed placenta. The differentiation of invasive trophoblasts is a fundamental process of placentation, the abnormalities of which are tightly associated with pregnancy disorders including preeclampsia (PE). Monoclonal nonspecific suppressor factor beta (MNSFβ) is an immunosuppressive factor. Its conventional knockout in mice induced embryonic lethality, whereas the underlying mechanism of MNSFβ in regulating placentation and pregnancy maintenance remains to be elucidated. Methods: Trophoblast‐specific knockout of MNSFβ was generated using Cyp19‐Cre mice. In situ hybridization (ISH), haematoxylin and eosin (HE), immunohistochemistry (IHC) and immunofluorescence (IF) were performed to examine the distribution of MNSFβ and insulin‐like growth factor 2 mRNA‐binding protein 2 (IGF2BP2) at the foeto‐maternal interface. The interaction and expression of MNSFβ, IGF2BP2 and invasion‐related molecules were detected by immunoprecipitation (IP), immunoblotting and quantitative real‐time polymerase chain reaction (qRT‐PCR). The cell invasion ability was measured by the Transwell insert assay. Results: We found that deficiency of MNSFβ in trophoblasts led to embryonic growth retardation by mid‐gestation and subsequent foetal loss, primarily shown as apparently limited trophoblast invasion. In vitro experiments in human trophoblasts demonstrated that the conjugation of MNSFβ with IGF2BP2 and thus the stabilization of IGF2BP2 essentially mediated the invasion‐promoting effect of MNSFβ. In the placentas from MNSFβ‐deficient mice and severe preeclamptic (PE) patients, downregulation of MNSFβ was evidently associated with the repressed IGF2BP2 expression. Conclusions: The findings reveal the crucial role of MNSFβ in governing the trophoblast invasion and therefore foetal development, and add novel hints to reveal the placental pathology of PE. [ABSTRACT FROM AUTHOR]

Preeclampsia (PE) is one of the main causes for the death of pregnant women. The developmental disorders of placental trophoblastic cells are related to the pathogenesis of PE. The malfunction of placenta may result in a high oxidative stress at the feto-maternal interface, which stimulates the excessive production of various factors from placenta. Those soluble placental factors are released into maternal circulation, eventually leading to the maternal symptoms of PE. Those hormones and molecules secreted by placenta, such as VEGF and anti -VEGF, methoxyestradiol, atrial natriuretic peptide, activin A and inhibin A, could partly reflect the developmental disorders of placenta. miRNAs and genetics were also found to be related to the pathogenesis of PE. [ABSTRACT FROM AUTHOR]

Abstract: The placenta is a transient organ that forms during pregnancy to support the growth and development of the fetus. During human placental development, trophoblast cells differentiate through two major pathways. In the villous pathway, cytotrophoblast cells fuse to form multinucleated syncytiotrophoblast. In the extravillous pathway, cytotrophoblast cells acquire an invasive phenotype and differentiate into either (1) interstitial extravillous trophoblasts, which invade the decidua and a portion of the myometrium, or (2) endovascular extravillous trophoblasts, which remodel the maternal vasculature. These differentiation events are tightly controlled by the interplay of oxygen tension, transcription factors, hormones, growth factors, and other signaling molecules. More recently, microRNAs have been implicated in this regulatory process. Abnormal placental development, particularly the limited invasion of trophoblast cells into the uterus and the subsequent failure of the remodeling of maternal spiral arteries, is believed to cause preeclampsia, a severe pregnancy related disorder characterized by hypertension and proteinuria. Oxidative stress, the abnormal production and/or function of signaling molecules, as well as aberrant microRNAs expression have been suggested to participate in the pathogenesis of preeclampsia. Several potential biomarkers for preeclampsia have been identified, creating new opportunities for the development of strategies to diagnose, prevent, and treat this disorder. [Copyright &y& Elsevier]