Analysis of gene expression identifies candidate markers and pathways in pre-eclampsia

Insufficient expression of COL6A1 promotes the development of early-onset severe preeclampsia by inhibiting the APJ/AKT signaling pathway

Early-onset severe preeclampsia (eosPE) is one of the most severe complications of pregnancy. To identify the genes related to the development of eosPE. We downloaded and integrated analyzed microarray data from GSE44711, GSE66273, and GSE74341, which contains the expression profile of placental tissues from patients with eosPE and healthy controls. Our analysis revealed that collagen type VI alpha 1 (COL6A1) was downregulated in the eosPE placenta compared to normal pregnancy. COL6A1 promoted the migration, invasion and tube formation ability of HTR8/SVneo cells, HUVECs and primary extravillous trophoblasts (EVTs). To explore the underlying mechanisms, we conducted transcriptome sequencing, which indicated that the Apelin/APJ signaling pathway was affected by COL6A1 knockdown. In addition, we found that APJ expression was lower in the placental tissue of patients with eosPE compared to healthy pregnancies. Inhibition of APJ suppressed the invasion, migration, and tube formation abilities of trophoblasts. We also observed that COL6A1 increased the levels of p-AKT and p-mTOR, while the APJ inhibitor ML221 impaired this effect. Furthermore, transwell and tube formation assays demonstrated that ML221 attenuated the capabilities enhanced by COL6A1, an effect that could be rescued by the AKT activator SC79. Overall, these findings indicate that insufficient expression of COL6A1 attenuates the migration, invasion, and endothelial-like tube formation of HTR8/SVneo cells and primary EVTs via the APJ/AKT/mTOR pathway, thereby promoting the development of eosPE.

Combining RNAscope, Immunohistochemistry (IHC) and Digital Image Analysis to Assess Podoplanin (PDPN) Protein and PDPN_mRNA Expression on Formalin-Fixed Paraffin-Embedded Normal Human Placenta Tissues

The expression and function of podoplanin (PDPN) in the normal human placenta has been debated in placental evaluation. This study emphasizes the importance of a multimodal approach of PDPN expression in normal human placentas. A complete examination is performed using immunohistochemistry, RNAscope and automated Digital Image examination (DIA) interpretation. QuPath DIA-based analysis automatically generated the stromal and histological scores of PDPN expression for immunohistochemistry and RNAscope stains. The umbilical cord's isolated fibroblasts and luminal structures expressed PDPN protein and PDPN_mRNA. RNAscope detected PDPN_mRNA upregulation in syncytial placental knots trophoblastic cells, but immunohistochemistry did not certify this at the protein level. The study found a significant correlation between the IHC and RNAscope H-Score (p = 0.033) and Allred Score (p = 0.05). A successful multimodal strategy for PDPN assessment in human placentas confirmed PDPN expression heterogeneity in the full-term human normal placenta and umbilical cord at the protein and mRNA level. In placental syncytial knots trophoblastic cells, PDPN showed mRNA overexpression, suggesting a potential role in placenta maturation.

TidyGEO: preparing analysis-ready datasets from Gene Expression Omnibus

TidyGEO is a Web-based tool for downloading, tidying, and reformatting data series from Gene Expression Omnibus (GEO). As a freely accessible repository with data from over 6 million biological samples across more than 4000 organisms, GEO provides diverse opportunities for secondary research. Although scientists may find assay data relevant to a given research question, most analyses require sample-level annotations. In GEO, such annotations are stored alongside assay data in delimited, text-based files. However, the structure and semantics of the annotations vary widely from one series to another, and many annotations are not useful for analysis purposes. Thus, every GEO series must be tidied before it is analyzed. Manual approaches may be used, but these are error prone and take time away from other research tasks. Custom computer scripts can be written, but many scientists lack the computational expertise to create such scripts. To address these challenges, we created TidyGEO, which supports essential data-cleaning tasks for sample-level annotations, such as selecting informative columns, renaming columns, splitting or merging columns, standardizing data values, and filtering samples. Additionally, users can integrate annotations with assay data, restructure assay data, and generate code that enables others to reproduce these steps.

Integrated Proteomic and N-Glycoproteomic Profiling of Placental Tissues of Patients with Preeclampsia

Background

Preeclampsia (PE) is a multi-system disorder of pregnancy that poses a serious threat to maternal and perinatal health worldwide. This study aims to evaluate the global alterations of protein expression and N-glycosylations that are crucial for PE pathogenesis. Here, tandem mass tag labeling combined with LC-MS/MS was employed to determine the global expression of all proteins and intact glycopeptide in placentas from three healthy pregnant women, three patients with early-onset severe PE, and three patients with late-onset severe PE.

Results

A total of 2260 proteins were quantified across 9 placental tissues, of which 37 and 23 were differentially expressed in the early-onset and late-onset PE groups, compared to the controls. A total of 789 glycopeptides were accurately quantified, which were derived from 204 glycosylated sites in 159 glycoproteins and were modified by 59 N-Linked glycans. A total of 123 differently expressed glycopeptides, which were from 47 glycoproteins were identified among three groups. Through a combined analysis of proteomic and glycoproteomic data, it was found that the changes in 10 glycoproteins were caused by the difference in glycosylation level but not in the protein abundance level.

Conclusion

This is the first study to conduct an integrated proteomic and glycoproteomic characterization of placental tissues of PE patients. Our findings suggest that glycosylation modification may affect the molecular function of proteins through changes in the glycosylation structure or the occupancy of glycosylation, which will provide new insights to help elucidating the pathogenic mechanism of PE.

HOXC8 alleviates high glucose-triggered damage of trophoblast cells during gestational diabetes mellitus via activating TGFβ1-mediated Notch1 pathway

Gestational diabetes mellitus (GDM) is an increasingly frequent disease occurred during pregnancy. HOXC8 has been disclosed to take part in the regulation of cancers. Additionally, the HOXC8 expression was dramatically decreased in the placenta of pre-eclampsia patients, but its expression and function have not been investigated in GDM. In this work, it was demonstrated that the mRNA and protein expression of HOXC8 was lower in GDM placenta tissues and GDM cell model. In addition, HOXC8 facilitated trophoblast cell proliferation and weakened trophoblast cell mitochondrial apoptosis. HOXC8 enhanced trophoblast cell migration and angiogenesis. Moreover, HOXC8 activated the TGFβ1-mediated Notch1 signaling pathway. Results showed that the mRNA and protein expressions of TGFβ1 and Notch1 were both lower in the GDM group than that in the NP group. Besides, there were positive correlations among HOXC8, TGFβ1 and Notch1. Inhibition of TGFβ1 (SB202190 treatment) reversed the effects of HOXC8 on trophoblast cells through modulating cell proliferation, mitochondrial apoptosis, migration and angiogenesis. At last, through in vivo experiments, it was identified that HOXC8 relieved GDM symptoms in vivo. In conclusion, HOXC8 alleviated HG-stimulated damage of trophoblast cells during GDM through activating TGFβ1-mediated Notch1 pathway. This discovery may provide a novel and useful bio-target for GDM treatment.

The correlation between proteoglycan 2 and neuropsychiatric systemic lupus erythematosus

The proposed pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE) mainly includes ischemia and neuroinflammation mechanisms. Protein encoded by Proteoglycan 2 (PRG2) mRNA is involved in the immune process related to eosinophils, also being found in the placenta and peripheral blood of pregnant women. We evaluated the correlation between PRG2 and NPSLE for the first time and found that PRG2 protein is overexpressed in the serum of patients with NPSLE and correlated with the SLE disease activity index (SLEDAI) subset scores of psychosis. Moreover, we investigated the correlation between hippocampal PRG2 level and hippocampally dependent learning and memory ability in MRL/lpr mice, and discovered that the number of PRG2⁺GFAP⁺ astrocytes in the cortex and hypothalamus and the number of PRG2⁺IBA-1⁺ microglia in the hippocampus and cortex significantly increased in the MRL/lpr mice. These data provided a reference for the follow-up exploration of the role of PRG2 in SLE or other diseases.

PRG2 and AQPEP are misexpressed in fetal membranes in placenta previa and percreta†

The obstetrical conditions placenta accreta spectrum (PAS) and placenta previa are a significant source of pregnancy-associated morbidity and mortality, yet the specific molecular and cellular underpinnings of these conditions are not known. In this study, we identified misregulated gene expression patterns in tissues from placenta previa and percreta (the most extreme form of PAS) compared with control cases. By comparing this gene set with existing placental single-cell and bulk RNA-Seq datasets, we show that the upregulated genes predominantly mark extravillous trophoblasts. We performed immunofluorescence on several candidate molecules and found that PRG2 and AQPEP protein levels are upregulated in both the fetal membranes and the placental disk in both conditions. While this increased AQPEP expression remains restricted to trophoblasts, PRG2 is mislocalized and is found throughout the fetal membranes. Using a larger patient cohort with a diverse set of gestationally aged-matched controls, we validated PRG2 as a marker for both previa and PAS and AQPEP as a marker for only previa in the fetal membranes. Our findings suggest that the extraembryonic tissues surrounding the conceptus, including both the fetal membranes and the placental disk, harbor a signature of previa and PAS that is characteristic of EVTs and that may reflect increased trophoblast invasiveness.

Excess fibronectin 1 participates in pathogenesis of pre-eclampsia by promoting apoptosis and autophagy in vascular endothelial cells

Plasma fibronectin 1 (FN1) levels are elevated in individuals with pre-eclampsia (PE), which may be applied as a possible b marker for vascular endothelial injury during PE. In the present study, the possible role of FN1 in the pathogenesis of PE and regulation of apoptosis and autophagy in vascular endothelial cells was explored. Plasma FN1 levels in 80 patients with PE and 40 healthy pregnant individuals were measured using ELISA to verify its relationship with the severity of PE. pcDNA3.1-FN1 or FN1-small interfering (si) RNA was used to manipulate the expression of FN1 in human umbilical vein endothelial cells (HUVECs) to assess the effects of FN1 on cell apoptosis, autophagy, and the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mechanistic target of rapamycin (mTOR) signaling pathway. It was found that upregulation of FN1 promoted apoptosis and autophagy, in addition to significantly inhibiting the activation of AKT and mTOR in HUVECs. By contrast, downregulation of FN1 expression inhibited cell apoptosis and autophagy, but increased AKT and mTOR phosphorylation in HUVECs that were cultured in serum samples obtained from patients with PE. Rescue experiments found that the PI3K/AKT inhibitor LY294002 reversed the effects of FN1-siRNA on apoptosis and autophagy in HUVECs cultured in serum from patients with PE. Therefore, data from the present study suggest that FN1 participates in the pathogenesis of PE by promoting apoptosis and autophagy in vascular endothelial cells, which is associated with the PI3K/AKT/mTOR signaling pathway.

New functions for old factors: the role of polyamines during the establishment of pregnancy

Implantation is essential for the establishment of a successful pregnancy, and the preimplantation period plays a significant role in ensuring implantation occurs in a timely and coordinated manner. This requires effective maternal-embryonic signalling, established during the preimplantation period, to synchronise development. Although multiple factors have been identified as present during this time, the exact molecular mechanisms involved are unknown. Polyamines are small cationic molecules that are ubiquitously expressed from prokaryotes to eukaryotes. Despite being first identified over 300 years ago, their essential roles in cell proliferation and growth, including cancer, have only been recently recognised, with new technologies and interest resulting in rapid expansion of the polyamine field. This review provides a summary of our current understanding of polyamine synthesis, regulation and function with a focus on recent developments demonstrating the requirements for polyamines during the establishment of pregnancy up to the implantation stage, in particular the role of polyamines in the control of embryonic diapause and the identification of an alternative pathway for their synthesis in sheep pregnancy. This, along with other novel discoveries, provides new insights into the control of the peri-implantation period in mammals and highlights the complexities that exist in regulating this critical period of pregnancy.

Integrated microarray analysis of key genes and a miRNA‑mRNA regulatory network of early‑onset preeclampsia

Early‑onset preeclampsia (EOPE) is a serious threat to maternal and foetal health. The present study aimed to identify potential biomarkers and targets for the treatment of EOPE. Expression profiles of placenta from patients with EOPE and healthy controls (GSE103542, GSE74341 and GSE44711) were downloaded from the Gene Expression Omnibus database. Integrated analysis revealed 246 genes and 28 microRNAs (miRNAs) that were differentially expressed between patients with EOPE and healthy controls. Differentially expressed genes (DEGs) were primarily enriched in 'biological processes', such as 'cell adhesion', 'female pregnancy', 'extracellular matrix organization' and 'response to hypoxia'. Significant pathways associated with DEGs primarily included 'focal adhesion', 'ECM‑receptor interaction', 'PI3K‑Akt signaling' and 'ovarian steroidogenesis'. A Protein‑Protein Interaction network of DEGs was constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins online database, and epidermal growth factor receptor, collagen α‑1(I) chain, secreted phosphoprotein 1, leptin (LEP), collagen α‑2(I) chain (COL1A2), plasminogen activator inhibitor 1 (SERPINE1), Thy‑1 membrane glycoprotein, bone morphogenetic protein 4, vascular cell adhesion protein 1 and matrix metallopeptidase 1 were identified as hub genes. The alterations of hsa‑miR‑937, hsa‑miR‑148b*, hsa‑miR‑3907, hsa‑miR‑367*, COL1A2, LEP and SERPINE1 in placenta were validated using our local samples. Our research showed that the expression of hsa‑miR‑937, hsa‑miR‑1486*, hsa‑miR‑3907, hsa‑miR‑367* and hub genes in the placenta were closely associated with the pathophysiology of EOPE. hsa‑miR‑937, hsa‑miR‑1486*, hsa‑miR‑3907, hsa‑miR‑367* and hub genes could serve as biomarkers for diagnosis and as potential targets for the treatment of EOPE.

Differential gene expression elicited by ZIKV infection in trophoblasts from congenital Zika syndrome discordant twins

Zika virus (ZIKV) causes congenital Zika syndrome (CZS), which is characterized by fetal demise, microcephaly and other abnormalities. ZIKV in the pregnant woman circulation must cross the placental barrier that includes fetal endothelial cells and trophoblasts, in order to reach the fetus. CZS occurs in ~1-40% of cases of pregnant women infected by ZIKV, suggesting that mothers' infection by ZIKV during pregnancy is not deterministic for CZS phenotype in the fetus. Therefore, other susceptibility factors might be involved, including the host genetic background. We have previously shown that in three pairs of dizygotic twins discordant for CZS, neural progenitor cells (NPCs) from the CZS-affected twins presented differential in vitro ZIKV susceptibility compared with NPCs from the non-affected. Here, we analyzed human-induced-pluripotent-stem-cell-derived (hiPSC-derived) trophoblasts from these twins and compared by RNA-Seq the trophoblasts from CZS-affected and non-affected twins. Following in vitro exposure to a Brazilian ZIKV strain (ZIKVBR), trophoblasts from CZS-affected twins were significantly more susceptible to ZIKVBR infection when compared with trophoblasts from the non-affected. Transcriptome profiling revealed no differences in gene expression levels of ZIKV candidate attachment factors, IFN receptors and IFN in the trophoblasts, either before or after ZIKVBR infection. Most importantly, ZIKVBR infection caused, only in the trophoblasts from CZS-affected twins, the downregulation of genes related to extracellular matrix organization and to leukocyte activation, which are important for trophoblast adhesion and immune response activation. In addition, only trophoblasts from non-affected twins secreted significantly increased amounts of chemokines RANTES/CCL5 and IP10 after infection with ZIKVBR. Overall, our results showed that trophoblasts from non-affected twins have the ability to more efficiently activate genes that are known to play important roles in cell adhesion and in triggering the immune response to ZIKV infection in the placenta, and this may contribute to predict protection from ZIKV dissemination into fetuses' tissues.

Biological importance of podoplanin expression in chorionic villous stromal cells and its relationship to placental pathologies

Podoplanin, a reliable marker of lymphatic endothelium, is a mucin-type transmembrane protein. Although the human placenta is devoid of a lymphatic system, chorionic villous stromal (CVS) cells express podoplanin. In this study, the pattern of podoplanin expression in normal and pathological placental tissues and the biological role of podoplanin were investigated. In total, 198 placental tissues belonging to 184 patients, seen at the Department of Pathology of Bulent Ecevit University Education and Research Hospital, Zonguldak, Turkey, were evaluated histopathologically and determined to meet the study criteria. The tissues were assigned to control, cisternal placental disorders, inflammation and hypoxic-ischemic pathology groups. Podoplanin expression in CVS cells was graded from 0 to 3 depending on the staining intensity, as determined by an immunohistochemical evaluation of chorionic villi in the most intensively stained tissue region. Podoplanin levels in control CVS cells increased in parallel with placental maturation, whereas in molar pregnancies podoplanin expression was lower than in control tissues. In the acute placental inflammation group, podoplanin immunoreactivity was similar to that in the control group, whereas in the preeclampsia group, podoplanin expression was higher than in all other groups. Our study showed an increase in podoplanin expression in CVS cells during pregnancy. In preeclamptic patients, the increase in podoplanin expression may be a response to hypoxic-ischemic conditions, whereas in molar pregnancies the decrease in podoplanin levels may cause villous swelling by disrupting intercellular fluid homeostasis.

Vascular endothelial growth factor C participates in regulation of maspin in extravillous trophoblast cell migration and invasion

Mammary serine protease inhibitor (maspin ; also known as serpin family B member 5 (SERPINB5)) plays a vital role in regulating the biological functions of extravillous trophoblast (EVT) cells, but the mechanism remains unclear. Vascular endothelial growth factor (VEGF ) C is a signature angiogenic molecule expressed and secreted by first-trimester trophoblasts, and bioinformatics analyses has revealed upregulation of VEGFC in pre-eclampsia. The aim of this study was to explore whether maspin regulates EVT cells by regulating the expression of VEGFC . Reverse transcription-polymerase chain reaction and western blotting were used to investigate the effects of hypoxia on the expression of VEGFC in EVT cells. Cells were treated with recombinant (r) maspin and decitabine (to selectively inhibit DNA methyltransferases and then upregulate maspin gene expression), and the effects on VEGFC expression evaluated. In addition, the effects of rVEGFC on the biological functions of EVT cells invitro were evaluated using cell migration and invasion assays. Hypoxia increased the expression of VEGFC in EVT cells. rMaspin upregulated the expression of VEGFC in normoxic EVT cells, and downregulated the expression of VEGFC in hypoxic EVT cells at 24h. Decitabine increased VEGFC expression in normoxic EVT cells, but had no significant effect on VEGFC expression in hypoxic EVT cells. rVEGFC promoted the migration and invasion of normoxic EVT cells and inhibited the invasion of hypoxic EVT cells. These results suggest that VEGFC is involved in the regulation of maspin in EVT cell migration and invasion. However, other molecular mechanisms may be involved and require further investigation.

A Co-expression Analysis of the Placental Transcriptome in Association With Maternal Pre-pregnancy BMI and Newborn Birth Weight

Maternal body mass index (BMI) before pregnancy is known to affect both fetal growth and later-life health of the newborn, yet the implicated molecular mechanisms remain largely unknown. As the master regulator of the fetal environment, the placenta is a valuable resource for the investigation of processes involved in the developmental programming of metabolic health. We conducted a genome-wide placental transcriptome study aiming at the identification of functional pathways representing the molecular link between maternal BMI and fetal growth. We used RNA microarray (Agilent 8 × 60 K), medical records, and questionnaire data from 183 mother-newborn pairs from the ENVIRONAGE birth cohort study (Flanders, Belgium). Using a weighted gene co-expression network analysis, we identified 17 correlated gene modules. Three of these modules were associated with both maternal pre-pregnancy BMI and newborn birth weight. A gene cluster enriched for genes involved in immune response and myeloid cell differentiation was positively associated with maternal BMI and negatively with low birth weight. Two other gene modules, upregulated in association with maternal BMI as well as birth weight, were involved in processes related to organ and tissue development, with blood vessel morphogenesis and extracellular matrix structure as top Gene Ontology terms. In line with this, erythrocyte-, angiogenesis-, and extracellular matrix-related genes were among the identified hub genes. The association between maternal BMI and newborn weight was significantly mediated by gene expression for 5 of the hub genes (FZD4, COL15A1, GPR124, COL6A1, and COL1A1). As some of the identified hub genes have been linked to obesity in adults, our observation in placental tissue suggests that biological processes may be affected from prenatal life onwards, thereby identifying new molecular processes linking maternal BMI and fetal metabolic programming.

Analysis of the Epigenome in Multiplex Pre-eclampsia Families Identifies SORD, DGKI, and ICA1 as Novel Candidate Risk Genes

Pre-eclampsia is a serious heritable disorder that affects 5-8% of pregnancies worldwide. While classical genetic studies have identified several susceptibility genes they do not fully explain the heritability of pre-eclampsia. An additional contribution to risk can be quantified by examining the epigenome, in particular the methylome, which is a representation of interactions between environmental and genetic influences on the phenotype. Current array-based epigenetic studies only examine 2-5% of the methylome. Here, we used whole-genome bisulfite sequencing (WGBS) to determine the entire methylome of 13 individuals from two multiplex pre-eclampsia families, comprising one woman with eclampsia, six women with pre-eclampsia, four women with uncomplicated normotensive pregnancies and two male relatives. The analysis of WGBS profiles using two bioinformatics platforms, BSmooth and Bismark, revealed 18,909 differentially methylated CpGs and 4157 differentially methylated regions (DMRs) concordant in females. The methylation patterns support the involvement of previously reported candidate genes, including COL4A1, SLC2A4, PER3, FLT1, GPI, LCT, DDAH1, TGFB3, DLX5, and LRP1B. Statistical analysis of DMRs revealed three novel genes significantly correlated with pre-eclampsia: sorbitol dehydrogenase (SORD, p = 9.98 × 10^-6), diacylglycerol kinase iota (DGKI, p = 2.52 × 10^-5), and islet cell autoantigen 1 (ICA1, 7.54 × 10^-3), demonstrating the potential of WGBS in families for elucidating the role of epigenome in pre-eclampsia and other complex diseases.

Identification of potential crucial genes associated with early-onset pre-eclampsia via a microarray analysis

AIM

This study aimed to identify potential key genes related to early-onset pre-eclampsia (EOPET), and to obtain a better understanding of the molecular mechanisms of this disease.

METHODS

The microarray dataset GSE44711 was obtained from the Gene Expression Omnibus, including eight chorionic villi samples from EOPET placentas and eight normal controls. The differentially expressed genes (DEG) were identified using the LIMMA package, and their potential functions were predicted by Gene Ontology (GO) enrichment analysis. Furthermore, protein-protein interactions (PPI) were obtained from the STRING database, and the PPI network was visualized by Cytoscape software. Then, significant modules were screened out from the PPI network, and GO enrichment analysis for DEG in modules was performed. Also, the potential transcription factors (TF) regulating DEG in modules were predicted, and TF-DEG network was visualized by Cytoscape.

RESULTS

A total of 270 upregulated and 200 downregulated DEG were identified. A set of DEG was related to functions such as female pregnancy and hormone metabolic process (e.g. NGF). In PPI network modules, some DEG (e.g. SERPINE1 and FN1) were significantly associated with anatomical structure morphogenesis, and some other DEG (e.g. GZMA) were relevant to the immune system process. Furthermore, SERPINE1, NGF, and FN1 interacted with each other and were regulated by RELA.

CONCLUSION

The DEG related to hormone metabolic process (e.g. NGF), anatomical structure morphogenesis (e.g. SERPINE1 and FN1), and immune system process (e.g. GZMA) are predicted to play significant roles in the progress of EOPET, which will be confirmed by experiments in future.

Matrix metalloproteinase-2 C-735T and its interaction with matrix metalloproteinase-7 A-181G polymorphism are associated with the risk of preeclampsia: influence on total antioxidant capacity and blood pressure

Matrix metalloproteinase (MMP) -2 C-735 T and MMP-7 A-181 G genotypes were studied in 144 pregnant patients with mild and severe preeclampsia and 103 healthy pregnant women. Significantly higher frequencies of CT and TT genotypes in patients compared to controls increased the risk of preeclampsia by 2.42 and 3.13 times, respectively. In severe preeclamptic women in the presence of MMP-2 CT the level of total antioxidant capacity was significantly lower than MMP-2 CC genotype. Also, in the presence of MMP-2 CT + TT blood pressure was significantly increased compared to CC genotype in all the patients. The combined presence of MMP-2 T and the MMP-7 A alleles compared to MMP-2 C and MMP-7 A alleles significantly increased the risk of preeclampsia by 3.08-fold. Our findings demonstrate an association between the MMP-2 C-735 T polymorphism with blood pressure and the risk of preeclampsia. Also, in the presence of polymorphism total antioxidant capacity level decreased in severe preeclampsia. Impact statement What is already known on this subject: Matrix metalloproteinases (MMPs) including MMP-2 might be involved in the pathogenesis of preeclampsia through alteration of invasive ability of trophoblastic cells and abnormal placentation. In one available study the absence of association between MMP-2 C-735T polymorphism with gestational hypertension or preeclampsia has been reported. What the results of this study add: We found that the presence of MMP-2 C-735T polymorphism increased the risk of preeclampsia and there was a significantly lower level of total antioxidant capacity in the presence of the polymorphism in severe preeclampsia. Also, we found significantly higher systolic and diastolic blood pressures in the presence of MMP-2 C-735T polymorphism. We detected a synergism between the MMP-2 T and the MMP-7 A alleles that increased the risk of preeclampsia. What the implications are of these findings for clinical practice and/or further research: New findings of our study are involvement of lower activity MMP-2 -735 T allele and its synergism with MMP-7 A allele, low promoter activity allele, in the pathogenesis of preeclampsia through possible impairment of placentation and also by decreased total antioxidant capacity and increased blood pressure. Further association studies of the role of MMP-2 polymorphism and MMP-2 activity in relation to oxidative stress parameters and blood pressure could elucidate the role of MMP-2 and MMP-7 in the pathogenesis of preeclampsia.

Preeclampsia: novel insights from global RNA profiling of trophoblast subpopulations

BACKGROUND

The maternal signs of preeclampsia, which include the new onset of high blood pressure, can occur because of faulty placentation. We theorized that transcriptomic analyses of trophoblast subpopulations in situ would lend new insights into the role of these cells in preeclampsia pathogenesis.

OBJECTIVE

Our goal was to enrich syncytiotrophoblasts, invasive cytotrophoblasts, or endovascular cytotrophoblasts from the placentas of severe preeclampsia cases. Total RNA was subjected to global transcriptional profiling to identify RNAs that were misexpressed compared with controls.

STUDY DESIGN

This was a cross-sectional analysis of placentas from women who had been diagnosed with severe preeclampsia. Gestational age-matched controls were placentas from women who had a preterm birth with no signs of infection. Laser microdissection enabled enrichment of syncytiotrophoblasts, invasive cytotrophoblasts, or endovascular cytotrophoblasts. After RNA isolation, a microarray approach was used for global transcriptional profiling. Immunolocalization identified changes in messenger RNA expression that carried over to the protein level. Differential expression of non-protein-coding RNAs was confirmed by in situ hybridization. A 2-way analysis of variance of non-coding RNA expression identified particular classes that distinguished trophoblasts in cases vs controls. Cajal body foci were visualized by coilin immunolocalization.

RESULTS

Comparison of the trophoblast subtype data within each group (severe preeclampsia or noninfected preterm birth) identified many highly differentially expressed genes. They included molecules that are known to be expressed by each subpopulation, which is evidence that the method worked. Genes that were expressed differentially between the 2 groups, in a cell-type-specific manner, encoded a combination of molecules that previous studies associated with severe preeclampsia and those that were not known to be dysregulated in this pregnancy complication. Gene ontology analysis of the syncytiotrophoblast data highlighted the dysregulation of immune functions, morphogenesis, transport, and responses to vascular endothelial growth factor and progesterone. The invasive cytotrophoblast data provided evidence of alterations in cellular movement, which is consistent with the shallow invasion often associated with severe preeclampsia. Other dysregulated pathways included immune, lipid, oxygen, and transforming growth factor-beta responses. The data for endovascular cytotrophoblasts showed disordered metabolism, signaling, and vascular development. Additionally, the transcriptional data revealed the differential expression in severe preeclampsia of 2 classes of non-coding RNAs: long non-coding RNAs and small nucleolar RNAs. The long non-coding RNA, urothelial cancer associated 1, was the most highly up-regulated in this class. In situ hybridization confirmed severe preeclampsia-associated expression in syncytiotrophoblasts. The small nucleolar RNAs, which chemically modify RNA structure, also correlated with severe preeclampsia. Thus, we enumerated Cajal body foci, sites of small nucleolar RNA activity, in primary cytotrophoblasts that were isolated from control and severe preeclampsia placentas. In severe preeclampsia, cytotrophoblasts had approximately double the number of these foci as the control samples.

CONCLUSION

A laser microdissection approach enabled the identification of novel messenger RNAs and non-coding RNAs that were misexpressed by various trophoblast subpopulations in severe preeclampsia. The results suggested new avenues of investigation, in particular, the roles of PRG2, Kell blood group determinants, and urothelial cancer associated 1 in syncytiotrophoblast diseases. Additionally, many of the newly identified dysregulated molecules might have clinical utility as biomarkers of severe preeclampsia.

Whole-transcriptome analysis delineates the human placenta gene network and its associations with fetal growth

BACKGROUND

The placenta is the principal organ regulating intrauterine growth and development, performing critical functions on behalf of the developing fetus. The delineation of functional networks and pathways driving placental processes has the potential to provide key insight into intrauterine perturbations that result in adverse birth as well as later life health outcomes.

RESULTS

We generated the transcriptome-wide profile of 200 term human placenta using the Illumina HiSeq 2500 platform and characterized the functional placental gene network using weighted gene coexpression network analysis (WGCNA). We identified 17 placental coexpression network modules that were dominated by functional processes including growth, organ development, gas exchange and immune response. Five network modules, enriched for processes including cellular respiration, amino acid transport, hormone signaling, histone modifications and gene expression, were associated with birth weight; hub genes of all five modules (CREB3, DDX3X, DNAJC14, GRHL1 and C21orf91) were significantly associated with fetal growth restriction, and one hub gene (CREB3) was additionally associated with fetal overgrowth.

CONCLUSIONS

In this largest RNA-Seq based transcriptome-wide profiling study of human term placenta conducted to date, we delineated a placental gene network with functional relevance to fetal growth using a network-based approach with superior scale reduction capacity. Our study findings not only implicate potential molecular mechanisms underlying fetal growth but also provide a reference placenta gene network to inform future studies investigating placental dysfunction as a route to future disease endpoints.

Peculiarities of placental microRNA expression in pregnancies complicated by gestational diabetes mellitus and preeclampsia

The aim of study was to determine feasible changes of placental miRNAs expression profiles revealed by next generation sequencing (NGS) in pregnancies with GDM complicated or not with PE. Out of 27 miRNAs, studied expression was significantly different (FDR < 0.05) only for his-miR-45a. Comparative analysis of revealed reliable differences in expression of hsa-miR-4532 (p < 0.0001, FDR = 0.0008), hsa-miR-34c-5p (p < 0.0001, FDR = 0.0083), and hsa-miR-193b-5p (p < 0.0001, FDR = 0.0139) in pregnancy complicated by PE, without of GDM. The present results suggest that GDM and PE are associated with specific alterations in the placental miRNA expression profiles. Further studies are needed to verify the role of these microRNA in molecular mechanisms underlying GDM and PE pathogenesis.

Differential Expression of Extracellular Matrix and Adhesion Molecules in Fetal-Origin Amniotic Epithelial Cells of Preeclamptic Pregnancy

Preeclampsia is a common disease that can occur during human pregnancy and is a leading cause of both maternal and neonatal morbidity and mortality. Inadequate trophoblast invasion and deficient remodeling of uterine spiral arteries are associated with preeclampsia (PE). The development of this syndrome is thought to be related to multiple factors. Recently, we isolated patient-specific human amniotic epithelial cells (AECs) from the placentas of 3 women with normal pregnancy and 3 with preeclamptic pregnancy. Since the characteristics of human AECs in PE are different from those in normal pregnancy, we sought to confirm the genes differentially expressed between preeclamptic pregnancy and normal pregnancy. Therefore, we performed transcriptome analysis to investigate the candidate genes associated with the possible pathophysiology of preeclampsia. Pathway analysis was performed using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) and Kyoto Encyclopedia of Genes and Genomes (KEGG) online resource. In this study, we selected a total of 12 pathways and focused on extracellular matrix-related and biological adhesion molecules. Using RT-PCR array and real-time PCR, we confirmed that COL16A1, ITGB2, and LAMA3 were significantly up-regulated, but ITGA1, ITGA3, ITGA6, MMP1, MMP3, MMP10 and MMP11 were significantly down-regulated in preeclamptic fetal origin cells. Taken together, we suggest that the genes and pathways identified here may be responsible for the occurrence and development of PE, and controlling their expression may play a role in communication with fetal-maternal placenta to keep normal pregnancy.

Placental microRNA expression in pregnancies complicated by superimposed pre‑eclampsia on chronic hypertension

Pre-eclampsia (PE) is a complication of pregnancy that affects 5–8% of women after 20 weeks of gestation. It is usually diagnosed based on the de novo onset of hypertension and proteinuria. Preexisting hypertension in women developing PE, also known as superimposed PE on chronic hypertension (SPE), leads to elevated risk of maternal and fetal mortality. PE is associated with an altered microRNA (miRNA) expression pattern in the placenta, suggesting that miRNA deregulation is involved in the pathogenesis of PE. Whether and how the miRNA expression pattern is changed in the SPE placenta remains unclear. The present study analyzed the placental miRNA expression profile in pregnancies complicated by SPE. miRNA expression profiles in SPE and normal placentas were investigated using an Ion Torrent sequencing system. Sequencing data were processed using a comprehensive analysis pipeline for deep miRNA sequencing (CAP-miRSeq). A total of 22 miRNAs were identified to be deregulated in placentas from patients with SPE. They included 16 miRNAs previously known to be associated with PE and 6 novel miRNAs. Among the 6 novel miRNAs, 4 were upregulated (miR-518a, miR-527, miR-518e and miR-4532) and 2 downregulated (miR-98 and miR-135b) in SPE placentas compared with controls. The present results suggest that SPE is associated with specific alterations in the placental miRNA expression pattern, which differ from alterations detected in PE placentas, and therefore, provide novel targets for further investigation of the molecular mechanisms underlying SPE pathogenesis.