Human placenta and trophoblasts simultaneously express three isoforms of atypical protein kinase-c.

Atypical protein kinase-c (aPKC) isoforms are important regulators of polarity and stem cell differentiation. There are three isoforms of aPKC: aPKC-ι, aPKC-ζ, and PKM-ζ. Recently, aPKC-ι was shown to regulate human trophoblast stem cell (TSC) differentiation. Compensation by remaining isoforms when a single aPKC isoform is lost can occur, but the expression pattern of aPKC-ζ in placenta is unknown. Here we show that aPKC-ι, aPKC-ζ and a new isoform, aPKC-ζ III, are expressed in trophoblasts. Therefore, studies examining the role of aPKC isoforms that control for potential compensation between aPKC isoforms are necessary to understand aPKC-mediated regulation of TSC differentiation.

Placental SARS-CoV-2 distribution correlates with level of tissue oxygenation in COVID-19-associated necrotizing histiocytic intervillositis/perivillous fibrin deposition.

INTRODUCTION: Recent evidence supports the - rare - occurrence of vertical transplacental SARS-CoV-2 transmission. We previously determined that placental expression of angiotensin-converting enzyme 2 (ACE2), the SARS-CoV-2 receptor, and associated viral cell entry regulators is upregulated by hypoxia. In the present study, we utilized a clinically relevant model of SARS-CoV-2-associated chronic histiocytic intervillositis/massive perivillous fibrin deposition (CHIV/MPFVD) to test the hypothesis that placental hypoxia may facilitate placental SARS-CoV-2 infection. METHODS: We performed a comparative immunohistochemical and/or RNAscope in-situ hybridization analysis of carbonic anhydrase IX (CAIX, hypoxia marker), ACE2 and SARS-CoV-2 expression in free-floating versus fibrin-encased chorionic villi in a 20-weeks' gestation placenta with SARS-CoV-2-associated CHIV/MPVFD. RESULTS: The levels of CAIX and ACE2 immunoreactivity were significantly higher in trophoblastic cells of fibrin-encased villi than in those of free-floating villi, consistent with hypoxia-induced ACE2 upregulation. SARS-CoV-2 showed a similar preferential localization to trophoblastic cells of fibrin-encased villi. DISCUSSION: The localization of SARS-CoV-2 to hypoxic, fibrin-encased villi in this placenta with CHIV/MPVFD suggests placental infection and, therefore, transplacental SARS-CoV-2 transmission may be promoted by hypoxic conditions, mediated by ACE2 and similar hypoxia-sensitive viral cell entry mechanisms. Understanding of a causative link between placental hypoxia and SARS-CoV-2 transmittability may potentially lead to the development of alternative strategies for prevention of intrauterine COVID-19 transmission.

Comparative matrix metalloproteinase-2 and -9 expression and activity during endotheliochorial and hemochorial trophoblastic invasiveness.

To establish a functional placenta, its development needs adequate trophoblastic invasiveness. The intricate and complex morphological and molecular aspects regulating trophoblastic invasion during endotheliochorial placentation of domestic carnivores and their similarities and differences with the hemochorial placenta are still poorly understood. During placentation processes, from the time of implantation, trophoblast cells invade the uterine endometrium where they achieve extensive degradation and remodeling of extracellular matrix components; in this process, matrix metalloproteinases (MMPs), particularly MMP-2 and 9, have an essential role in rebuilding, cell migration, and invasiveness. This review provides an overview of comparative trophoblast invasive events and the expression and activity of MMP-2 and 9 during endotheliochorial and hemochorial placentation, emphasizing dog and mouse placental models. Understanding of trophoblastic invasiveness in two models of placentation, the intermediately invasive domestic carnivore endotheliochorial placenta, and the more highly invasive mouse hemochorial placenta, contributes to deepen knowledge of the trophoblast invasive processes and their diverse and complex human placental alterations, such as preeclampsia.

Circulating syndecan-1 is reduced in pregnancies with poor fetal growth and its secretion regulated by matrix metalloproteinases and the mitochondria.

Fetal growth restriction is a leading cause of stillbirth that often remains undetected during pregnancy. Identifying novel biomarkers may improve detection of pregnancies at risk. This study aimed to assess syndecan-1 as a biomarker for small for gestational age (SGA) or fetal growth restricted (FGR) pregnancies and determine its molecular regulation. Circulating maternal syndecan-1 was measured in several cohorts; a large prospective cohort collected around 36 weeks' gestation (n = 1206), a case control study from the Manchester Antenatal Vascular service (285 women sampled at 24-34 weeks' gestation); two prospective cohorts collected on the day of delivery (36 + 3-41 + 3 weeks' gestation, n = 562 and n = 405 respectively) and a cohort who delivered for preterm FGR (< 34 weeks). Circulating syndecan-1 was consistently reduced in women destined to deliver growth restricted infants and those delivering for preterm disease. Syndecan-1 secretion was reduced by hypoxia, and its loss impaired proliferation. Matrix metalloproteinases and mitochondrial electron transport chain inhibitors significantly reduced syndecan-1 secretion, an effect that was rescued by coadministration of succinate, a mitochondrial electron transport chain activator. In conclusion, circulating syndecan-1 is reduced among cases of term and preterm growth restriction and has potential for inclusion in multi-marker algorithms to improve detection of poorly grown fetuses.

FURIN and placental syncytialisation: a cautionary tale.

FURIN is a pro-protein convertase previously shown to be important for placental syncytialisation (Zhou et al. [1]), a process of cell fusion whereby placental cytotrophoblast cells fuse to form a multinucleated syncytium. This finding has been broadly accepted however, we have evidence suggesting the contrary. Spontaneously syncytialising term primary human trophoblast cells and BeWo choriocarcinoma cells were treated with either FURIN siRNA or negative control siRNA or the protease inhibitor, DEC-RVKR-CMK, or vehicle. Cells were then left to either spontaneously syncytialise (primary trophoblasts) or were induced to syncytialise with forskolin (BeWo). Effects on syncytialisation were measured by determining human chorionic gonadotrophin secretion and E-cadherin protein levels. We showed that FURIN is not important for syncytialisation in either cell type. However, in primary trophoblasts another protease also inhibited by DEC-RVKR-CMK, may be involved. Our results directly contrast with those published by Zhou et al. Zhou et al. however, used first trimester villous explants to study syncytialisation, and we used term primary trophoblasts. Therefore, we suggest that FURIN may be involved in syncytialisation of first trimester trophoblasts, but not term trophoblasts. What is more concerning is that our results using BeWo cells do not agree with their results, even though for the most part, we used the same experimental design. It is unclear why these experiments yielded different results, however we wanted to draw attention to simple differences in measuring syncytialisation or flaws in method reporting (including omission of cell line source and passage numbers, siRNA concentration and protein molecular weights) and choice of immunoblot loading controls, that could impact on experimental outcomes. Our study shows that careful reporting of methods by authors and thorough scrutiny by referees are vital. Furthermore, a universal benchmark for measuring syncytialisation is required so that various studies of syncytialisation can be validated.

Iodothyronine deiodinase 2 (DiO2) regulates trophoblast cell line cycle, invasion and apoptosis; and its downregulation is associated with early recurrent miscarriage.

INTRODUCTION: Trophoblast development is a crucial event in placentation and pregnancy complications but its underlying mechanisms remain unclear. Thus, we aimed at investigating the role of DiO2 in trophoblast cell line decisions and assessing its placental villous expression in early recurrent miscarriage (ERM) patients. METHODS: The placental villous expression of DiO2 was determined with immunofluorescence. Cell proliferation was measured with the CCK8 kit while cell-cycle and apoptosis were studied with flow-cytometry. Cell migration and invasion were measured with wound-healing and transwell assays, respectively. Gene expression was then assessed with RT-qPCR and western blotting. RESULTS: DiO2 is expressed in the CTB, PCT, DCT and STB of the placenta. Its overexpression arrested trophoblast cell line proliferation at the G1 phase of the cell-cycle by downregulating cyclin-D1 and PCNA, while promoting apoptosis via increased caspase-3 activity and inhibition of the AKT and ERK1/2 signaling pathways. Also, it augmented trophoblast cell line migration and invasion via the upregulation of N-cadherin, vimentin, fascin-1, twist-1 and other epithelial-mesenchymal transition genes. DiO2 knockdown elicited the opposite effects. Surprisingly, each of these effects of DiO2 manipulation was not mediated by thyroid hormone metabolism. Assessment of the ERM placental villi revealed a downregulation of DiO2, N-cadherin, vimentin, fascin-1 and twist-1. The expression of E-cadherin remained unchanged in these placentae. DISCUSSION: During placentation, DiO2 may inhibit trophoblast proliferation while facilitating their differentiation into an invasive phenotype; and that its downregulation may contribute to the shallow trophoblast invasion that precedes ERM. Hence, DiO2 is a potential therapeutic target against ERM.

Clinical and in Vitro Evidence against Placenta Infection at Term by Severe Acute Respiratory Syndrome Coronavirus 2.

Despite occasional reports of vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy, the question of placental infection and its consequences for the newborn remain unanswered. Herein, we analyzed the placentas of 31 coronavirus disease 2019-positive mothers by reverse transcriptase PCR, immunohistochemistry, and in situ hybridization. Only one case of placental infection was detected, which was associated with intrauterine demise of the fetus. Differentiated primary trophoblasts were then isolated from nonpathologic human placentas at term, differentiated, and exposed to SARS-CoV-2 virions. Unlike for positive control cells Vero E6, the virus inside cytotrophoblasts and syncytiotrophoblasts or in the supernatant 4 days after infection was undetectable. As a mechanism of defense, we hypothesized that trophoblasts at term do not express angiotensin-converting enzyme 2 and transmembrane protease serine 2 (TMPRSS2), the two main host membrane receptors for SARS-CoV-2 entry. The quantification of these proteins in the placenta during pregnancy confirmed the absence of TMPRSS2 at the surface of the syncytium. Surprisingly, a transiently induced experimental expression of TMPRSS2 did not allow the entry or replication of the virus in differentiated trophoblasts. Altogether, these results underline that trophoblasts are not likely to be infected by SARS-CoV-2 at term, but raise concern about preterm infection.

Ubiquitin-Specific Peptidase 5 is Involved in the Proliferation of Trophoblast Cells by Regulating Wnt/ß-Catenin Signaling.

Preeclampsia (PE) is a pathologic condition in pregnant women which accounts for the inhibition of proliferation, migration and invasion of trophoblast cells. This study aimed to investigate the regulation of ubiquitin-specific peptidase 5 (USP5) on the trophoblast cells in PE. Expressions of USP5 in the placentas of PE patients and healthy donors were examined by qRT-PCR and Western blot. Hypoxia/reoxygenation (H/R) model in trophoblast cells was further established. Cell viability was examined using CCK-8 assay. Finally, the effect of overexpression and silence of USP5 using lentivirus transduction was studied. Our results showed that USP5 was lowly expressed in the placentas of PE patients as well as in H/R-induced trophoblast cells. In the experiments of overexpression, USP5 promoted the proliferation of trophoblast cells, and up-regulated the expressions of ß-catenin and the downstream signals c-Myc and Cyclin D1 in trophoblast cells. On the other hand, silence of USP5 elicited the opposite results. The overexpression of USP5 in the H/R model greatly released the H/R-induced inhibition in the trophoblast cells, and moderated the down-regulation of ß-catenin and c-Myc induced by H/R. We concluded that USP5 promoted the proliferation of trophoblast cells via the up-regulation of the Wnt/ß-catenin signaling pathway.

Impaction of factors associated with oxidative stress on the pathogenesis of gestational hypertension and preeclampsia: A Chinese patients based study.

ABSTRACT: We aimed to investigate the effect of Kelch-like ECH-associated protein 1/NF-E2 p45-related factor 2 (Keap1/Nrf2) pathway on the biological function of trophoblast cells in oxidative stress model at the cellular level, and analyzed the expression level and clinical significance of Keap1/Nrf2 pathway and related antioxidant factors in placental tissues of Preeclampsia (PE) patients at clinical level. In present study, we found that under hypoxia/reoxygenation conditions, the activity of oxidative stress-related enzymes (CAT, GSH-Px, SOD) in HTR8/SVneo cells was significantly lower than that before treatment (P < .01). The activities of CAT, GSH-Px and SOD in HTR8/SVneo cells in SiRNA+H/R group decreased significantly (P < .01), indicating the important defense effect of Keap1/Nrf2 signaling pathway in oxidative stress. As a control group of Nrf2 SiRNA+H/R group, Si-NC+H/R group had CAT, GSH-Px and SOD activities decreasing, which was similar to that in H/R group. Moreover, the activities of oxidative stress-related active enzymes in patients with PE were further confirmed by detecting and comparing the activities of CAT, GSH-Px and SOD in placental tissues. The results showed that the activity of SOD (P < .001), GSH-Px (P < .01) and CAT (P < .01) in placental tissues of patients with PE were significant different from those of normal placental tissues. The expression level of Keap1 in placenta of patients with PE was slightly lower than that of normal placenta. While the expression of Nrf2 in placenta of patients with PE was significantly higher than that of normal placenta. HO-1 expression in placenta of patients with PE was significantly higher than that of normal placenta. These results implicate the importance of Keap-1/Nrf2 pathway in PE.

Angiopoietin 2 stimulates trophoblast invasion via a mechanism associated with JNK signaling.

Extravillous trophoblast cell (EVT) invasion is tightly controlled, and its dysregulation can lead to altered spiral artery remodeling and contribute to a number of different pregnancy complications. Angiopoietin-2 (Ang-2) is expressed by trophoblast cells and various cells in the decidua, and trophoblast cells express its receptor, Tie2. Ang-2 has been shown to play roles in tumor progression and metastasis but it is not known if it also regulates EVT invasion. Here, we show that both the HTR-8/SVneo cell line and primary isolates of human EVT expressed various integrins and the Tie2 receptor, and Ang-2 stimulated their migration and/or invasion. Ang-2 increased expression of matrix metalloproteinase (MMP)2 and MMP9, altered the cytoskeleton of HTR-8/SVneo cells and also induced phosphorylation of Tie2, JNK and c-Jun. Inhibition of p-JNK (using SP600125) blocked the Ang-2 induced invasion of HTR-8/SVneo cells. In addition, inhibition of Tie2 (pexmetinib) and integrin signaling (RGDS and ATN-161) also blocked Ang-2-induced invasion. In conclusion, we demonstrate that Ang-2 can stimulate EVT invasion via a mechanism associated with activation of both the Tie2 receptor and integrins, which appear to work through different pathways; Tie2 through the JNK/c-JUN pathway and integrins through an as yet unidentified pathway(s). We therefore propose that any alterations in Ang-2 expression in the decidua would lead to an imbalance in pro- and anti-invasive factors, disrupting regulation of EVT invasion and spiral artery remodeling and thereby contribute to the etiology of several complications of pregnancy.

Insulin-like growth factor 1 signaling in the placenta requires endothelial nitric oxide synthase to support trophoblast function and normal fetal growth.

Currently, there is no effective treatment for placental dysfunction in utero. In a ligated mouse model of fetal growth restriction (FGR), nanoparticle-mediated human insulin-like 1 growth factor (hIGF1) gene delivery (NP-Plac1-hIGF1) increased hIGF1 expression and maintained fetal growth. However, whether it can restore fetal growth remains to be determined. Using the endothelial nitric oxide synthase knockout (eNOS-/-) mouse model, a genetic model of FGR, we found that despite inducing expression of hIGF1 in the placentas treated with NP-Plac1-hIGF1 (P = 0.0425), FGR did not resolve. This was associated with no change to the number of fetal capillaries in the placental labyrinth; an outcome which was increased with NP-Plac1-hIGF1 treatment in the ligated mouse model, despite increased expression of angiopoietin 1 (P = 0.05), and suggested IGF1 signaling in the placenta requires eNOS to modulate placenta angiogenesis. To further assess this hypothesis, BeWo choriocarcinoma cell line and human placental explant cultures were treated with NP-Plac1-hIGF1, oxidative stress was induced with hydrogen peroxide (H2O2), and NOS activity was inhibited using the inhibitor NG-monomethyl-l-arginine (l-NMMA). In both BeWo cells and explants, the protective effect of NP-Plac1-hIGF1 treatment against H2O2-induced cell death/lactate dehydrogenase release was prevented by eNOS inhibition (P = 0.003 and P < 0.0001, respectively). This was associated with an increase in mRNA expression of oxidative stress markers hypoxia inducing factor 1α (HIF1α; P < 0.0001) and ADAM10 (P = 0.0002) in the NP-Plac1-hIGF1 + H2O2 + l-NMMA-treated BeWo cells. These findings show for the first time the requirement of eNOS/NOS in IGF1 signaling in placenta cells that may have implications for placental angiogenesis and fetal growth.

LncRNA H19-Derived miR-675-5p Accelerates the Invasion of Extravillous Trophoblast Cells by Inhibiting GATA2 and Subsequently Activating Matrix Metalloproteinases.

The invasion of extravillous trophoblast (EVT) cells into the maternal decidua, which plays a crucial role in the establishment of a successful pregnancy, is highly orchestrated by a complex array of regulatory mechanisms. Non-coding RNAs (ncRNAs) that fine-tune gene expression at epigenetic, transcriptional, and post-transcriptional levels are involved in the regulatory mechanisms of EVT cell invasion. However, little is known about the characteristic features of EVT-associated ncRNAs. To elucidate the gene expression profiles of both coding and non-coding transcripts (i.e., mRNAs, long non-coding RNAs (lncRNAs), and microRNAs (miRNAs)) expressed in EVT cells, we performed RNA sequencing analysis of EVT cells isolated from first-trimester placentae. RNA sequencing analysis demonstrated that the lncRNA H19 and its derived miRNA miR-675-5p were enriched in EVT cells. Although miR-675-5p acts as a placental/trophoblast growth suppressor, there is little information on the involvement of miR-675-5p in trophoblast cell invasion. Next, we evaluated a possible role of miR-675-5p in EVT cell invasion using the EVT cell lines HTR-8/SVneo and HChEpC1b; overexpression of miR-675-5p significantly promoted the invasion of both EVT cell lines. The transcription factor gene GATA2 was shown to be a target of miR-675-5p; moreover, small interfering RNA-mediated GATA2 knockdown significantly promoted cell invasion. Furthermore, we identified MMP13 and MMP14 as downstream effectors of miR-675-5p/GATA2-dependent EVT cell invasion. These findings suggest that miR-675-5p-mediated GATA2 inhibition accelerates EVT cell invasion by upregulating matrix metalloproteinases.

Single-cell RNA expression profiling of SARS-CoV-2-related ACE2 and TMPRSS2 in human trophectoderm and placenta.

OBJECTIVES: To examine the characteristics and distribution of possible severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) target cells in the human trophectoderm (TE) and placenta. METHODS: Bioinformatics analysis was performed based on published single-cell transcriptomic datasets of early TE and first- and second-trimester human placentae. We conducted the transcriptomic analysis of 4198 early TE cells, 1260 first-trimester placental cells and 189 extravillous trophoblast cells (EVTs) from 24-week placentae (EVT_24W) using the SMART-Seq2 method. In addition, to confirm the bioinformatic results, we performed immunohistochemical staining of three first-trimester, three second-trimester and three third-trimester placentae from nine women recruited prospectively to this study. We evaluated the expression of the SARS-CoV-2-related molecules angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2). RESULTS: Via bioinformatic analysis, we identified the existence of ACE2 and TMPRSS2 expression in human TE as well as in first- and second-trimester placentae. In the human TE, 54.4% of TE1 cells, 9.0% of cytotrophoblasts (CTBs), 3.2% of EVTs and 29.5% of syncytiotrophoblasts (STBs) were ACE2-positive. In addition, 90.7% of TE1 cells, 31.5% of CTBs, 22.1% of EVTs and 70.8% of STBs were TMPRSS2-positive. In placental cells, 20.4% of CTBs, 44.1% of STBs, 3.4% of EVTs from 8-week placentae (EVT_8W) and 63% of EVT_24W were ACE2-positive, while 1.6% of CTBs, 26.5% of STBs, 1.9% of EVT_8W and 20.1% of EVT_24W were TMPRSS2-positive. Pathway analysis revealed that EVT_24W cells that were positive for both ACE2 and TMPRSS2 (ACE2 + TMPRSS2-positive) were associated with morphogenesis of branching structure, extracellular matrix interaction, oxygen binding and antioxidant activity. The ACE2 + TMPRSS2-positive TE1 cells were correlated with an increased capacity for viral invasion, epithelial-cell proliferation and cell adhesion. Expression of ACE2 and TMPRSS2 was observed on immunohistochemical staining in first-, second- and third-trimester placentae. CONCLUSIONS: ACE2- and TMPRSS2-positive cells are present in the human TE and placenta in all three trimesters of pregnancy, which indicates the possibility that SARS-CoV-2 could spread via the placenta and cause intrauterine fetal infection. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Nesfatin-1 Promotes Proliferation, Migration and Invasion of HTR-8/SVneo Trophoblast Cells and Inhibits Oxidative Stress via Activation of PI3K/AKT/mTOR and AKT/GSK3ß Pathway.

Preeclampsia (PE) is a leading cause of perinatal and maternal mortality. Considering that Nesfatin-1 was reported to be downregulated in serum of PE patients, we aimed to explore the functional role of Nesfatin-1 in trophoblast cells. Cell transfection was conducted to overexpress or inhibit Nesfatin-1, and its expression was measured by quantitative PCR. Cell proliferation, migration, and invasion abilities were determined employing CCK-8, flow cytometry, wound-healing, and transwell assays. Immunofluorescence assay was performed to detect E-cadherin and vimentin. ROS, MDA, and SOD levels were measured using their corresponding commercial kits. Western blot was used to identify the expression of vital kinases in PI3K/AKT/mTOR or GSK3ß pathway and invasion-related proteins in trophoblast cells. Nesfatin-1 knockdown significantly suppressed proliferation, migration, and invasion and increased cell arrest in G1 phase, as well as downregulated expressions of MMP2/9 in HTR-8/SVneo cells. Besides, Nesfatin-1 knockdown promoted the expression of E-cadherin and reduced the expression of vimentin. Additionally, the levels of ROS, MDA, and SOD were elevated upon Nesfatin-1 knockdown. On the contrary, Nesfatin-1 overexpression exerted the opposite effects. Nesfatin-1 promoted the activation of PI3K/AKT/mTOR or GSK3ß pathway, blocking of which reversed the promotive effects on trophoblast invasion and the inhibitory effects on oxidative stress of Nesfatin-1 in HTR-8/SVneo cells. In short, this study revealed that Nesfatin-1 promoted trophoblast cell proliferation, migration, invasion, and EMT and suppressed oxidative stress by activating PI3K/AKT/mTOR and AKT/GSK3ß signaling pathway, laying the foundation for the development of therapeutic strategy for PE by targeting Nesfatin-1.

HDAC4 Knockdown Induces Preeclampsia Cell Autophagy and Apoptosis by miR-29b.

Preeclampsia (PE) is one of the main causes of maternal death and perinatal morbidity and mortality. Considering that histone deacetylase 4 (HDAC4) activity could relate to trophoblast cell motility and be antagonized by miR-29b, the aim of the present study was to investigate the ability of HDAC4 to regulate placental trophoblast cells by miR-29b. We assessed the cytological changes of PE patients, and the expression and cellular localization of HDAC4 and LC3 by histological analysis, immunohistochemistry, western blot assay, and immunofluorescence staining assay. We observed the effect of hypoxia on HDAC4, the correction of HDAC4/miR-29b, and the effects of HDAC4/miR-29b on HTR8 cells by dual-luciferase, quantitative real-time PCR, western blot assay, and flow cytometry assay. Here, we first found that HDAC4 was lowly expressed in PE tissues, while LC3 was highly expressed. In addition, the expression of HDAC4 was inhibited by hypoxia in HTR8 cells. Furthermore, our data showed that HDAC4 activity could be antagonized by miR-29b. We highlighted that miR-29b specifically targeted HDAC4 in trophoblast cells and both molecules were involved in a functional loop. Altogether, our findings demonstrated that silencing of HDAC4 could trigger cell autophagy and apoptosis directly by miR-29b in placental trophoblast cells of PE.

Downregulation of cAMP-Dependent Protein Kinase Inhibitor-b Promotes Preeclampsia by Decreasing Phosphorylated Akt.

Preeclampsia is a multi-system disease that is unique to human pregnancy. Impaired extravillous trophoblast migration and invasion accompanied by poor spiral vascular remodeling is thought to be the initial reason. This study investigated cAMP-dependent protein kinase inhibitor-b(PKIB) expression in placentas and its involvement in the pathogenesis of PE. We used immunohistochemistry and western blotting to calculate PKIB levels in the placentas. Then we knocked down PKIB by siRNA and used real-time cell analysis to assess the invasion and migration ability of trophoblasts. Tube formation assay and spheroid sprouting assay were utilized to identify the ability to form vessels of trophoblasts. At last, western blotting was used to demonstrate the level of phosphorylated Akt, as well as downstream-related genes of Akt signaling pathway in trophoblasts. We first found that PKIB expression level was lower in the PE placentas than in the normal placentas. In addition, we found that downregulation of PKIB can inhibit the migration, invasion, and the ability to form vessels of HTR8/SVneo cells. Downregulation of PKIB leaded to a decrease in phosphorylated Akt, as well as downstream proteins such as matrix metalloproteinase 2, matrix metalloproteinase 9, and glycogen synthase kinase 3ß, which are related to migration and invasion. Our study revealed that the downregulation of PKIB expression resulted in decreased migration, invasion, and vessel formation ability by regulating Akt signaling pathway in placental trophoblasts in PE.

Hypoxia-induced SPOP attenuates the mobility of trophoblast cells through inhibition of the PI3K/AKT/GSK3ß pathway.

Placental hypoxia has been implicated in pregnancy pathologies such as pre-eclampsia and intrauterine growth restriction. However, the underlying mechanism by which the trophoblasts respond to hypoxia remains unclear. Speckle-type POZ protein (SPOP), an E3 ubiquitin ligase adapter, was previously reported to play important roles in various physiological and pathological processes. This study aims to investigate the expression and biological functions of SPOP after exposure to cobalt chloride (CoCl2 )-mimicked hypoxia conditions using human trophoblast-derived choriocarcinoma cell lines and extravillous cytotrophoblast. These data showed that SPOP protein was directly induced by CoCl2 -mimicked hypoxia and regulated by HIF-1α at the posttranscription level. CoCl2 treatment could dramatically influence the localization of SPOP in trophoblasts, especially the accumulation of SPOP into the nucleus. In addition, both CoCl2 -mimicked hypoxia and induction of endogenous SPOP expression by lentivirus transfection attenuated the migration and invasion abilities of trophoblasts. Furthermore, we demonstrated that SPOP was involved in CoCl2 -induced the inhibition of the PI3K/AKT/GSK3ß pathway in placental trophoblasts. Taken together, these data indicate that accumulation of HIF-1α augments the expression of SPOP in trophoblasts, which impairs trophoblastic mobility by targeting the PI3K/AKT/GSK3ß pathway. This potentially leads to insufficient uterine spiral artery remodeling and suboptimal placental perfusion, and thus the development of pregnancy-related complication.

HDAC2-mediated proliferation of trophoblast cells requires the miR-183/FOXA1/IL-8 signaling pathway.

Pre-eclampsia (PE) is a major cause of maternal and perinatal death. Previous research has indicated the role of histone deacetylase 2 (HDAC2) in the pathogenesis of PE but the relevant molecular mechanisms are unknown. However, there is hitherto little information concerning the molecular mechanism behind HDAC2 in PE. Herein, we hypothesized that HDAC2 promotes trophoblast cell proliferation and this requires the involvement of microRNA-183 (miR-183), forkhead box protein A1 (FOXA1), and interleukin 8 (IL-8). We collected placental specimens from 30 PE affected and 30 normal pregnant women. HDAC2 and FOXA1 were poorly expressed while miR-183 and IL-8 were highly expressed in placental tissues in PE. In vitro, HDAC2 overexpression enhanced the proliferation, migration, and invasion of human trophoblast cells HTR-8/SVNEO. HDAC2 inhibited the expression of miR-183 by diminishing H4 acetylation in the miR-183 promoter region. miR-183 inhibition by its specific inhibitor increased the expression of FOXA1 and thus enhanced HTR-8/SVNEO cell proliferation, migration, and invasion. FOXA1, a transcriptional factor, enhanced HTR-8/SVNEO cell proliferation, migration, and invasion by inhibiting the transcription of IL-8. We also observed HDAC2 knockdown was lost upon FOXA1 overexpression, suggesting that HDAC2 could promote HTR-8/SVNEO proliferation, migration, and invasion through the miR-183/FOXA1/IL-8 pathway. In summary, the results highlighted the role of the HDAC2/miR-183/FOXA1/IL-8 pathway in PE pathogenesis and thus suggest a novel molecular target for PE.

Contribution of placental 11ß-HSD2 to the pathogenesis of preeclampsia.

Preeclampsia, a major human pregnancy-specific disorder, leads to maternal and fetal morbidity and mortality. Here we reported that 11ß-hydroxysteroid dehydrogenase type 2 (11ß-HSD2), an enzyme that degrades active glucocorticoids, is one of the key factors that contributes to preeclampsia development. In the pregnant rat model, we firstly confirmed that administration of 11ß-HSD2 inhibitor carbenoxolone (CBX) subcutaneously or by placenta-targeted delivery system could lead to a decrease in placental 11ß-HSD2 expression and activity and an increase in corticosterone level in placenta and maternal circulation. Then, we showed that subcutaneous administration and placenta-targeted delivery of CBX resulted in the hallmark of preeclampsia-like features including hypertension, proteinuria, renal damages as well as elevated circulatory soluble fms-like tyrosine kinase 1 (sFlt1) and increased sFlt1/placental growth factor (PlGF) ratio in pregnant rats. These animals displayed decreased trophoblast invasion in uterus, impaired spiral artery remodeling, and reduced placental blood flow. Preeclampsia-like features could also be induced by administration of dexamethasone in pregnant rats. In the cultured human trophoblast models, we found that cortisol only inhibited migration and invasion of the extravillous trophoblasts with 11ß-HSD2 knockdown, and promoted sFlt1 release in the cultured syncytiotrophoblasts with 11ß-HSD2 knockdown. Furthermore, we elucidated that cortisol stimulated a disintegrin and metalloprotease (ADAM)17 expression in placentas, thereby promoting sFlt1 release in placenta. Collectively, our study provided the evidence that placental 11ß-HSD2 dysfunction plays a key role in the development of preeclampsia and immediately identified innovative target to counteract preeclampsia.

Placental Alkaline Phosphatase Promotes Zika Virus Replication by Stabilizing Viral Proteins through BIP.

Zika virus (ZIKV) infection during pregnancy causes intrauterine growth defects and microcephaly, but knowledge of the mechanism through which ZIKV infects and replicates in the placenta remains elusive. Here, we found that ALPP, an alkaline phosphatase expressed primarily in placental tissue, promoted ZIKV infection in both human placental trophoblasts and astrocytoma cells. ALPP bound to ZIKV structural and nonstructural proteins and thereby prevented their proteasome-mediated degradation and enhanced viral RNA replication and virion biogenesis. In addition, the function of ALPP in ZIKV infection depends on its phosphatase activity. Furthermore, we demonstrated that ALPP was stabilized through interactions with BIP, which is the endoplasmic reticulum (ER)-resident heat shock protein 70 chaperone. The chaperone activity of BIP promoted ZIKV infection and mediated the interaction between ALPP and ZIKV proteins. Collectively, our findings reveal a previously unrecognized mechanism through which ALPP facilitates ZIKV replication by coordinating with the BIP protein.IMPORTANCE ZIKV is a recently emerged mosquito-borne flavivirus that can cause devastating congenital Zika syndrome in pregnant women and Guillain-Barré syndrome in adults, but how ZIKV specifically targets the placenta is not well understood. Here, we identified an alkaline phosphatase (ALPP) that is expressed primarily in placental tissue and promotes ZIKV infection by colocalizing with ZIKV proteins and preventing their proteasome-mediated degradation. The phosphatase activity of ALPP could be required for optimal ZIKV infection, and ALPP is stabilized by BIP via its chaperone activity. This report provides novel insights into host factors required for ZIKV infection, which potentially has implications for ZIKV infection of the placenta.