Implications for preeclampsia: hypoxia-induced Notch promotes trophoblast migration

Leveraging machine learning and bioinformatics to identify diagnostic biomarkers connected to hypoxia-related genes in preeclampsia

PE is a serious form of pregnancy-related hypertension. Hypoxia can induce cellular dysfunction, adversely affecting both the infant and the mother. This study aims to investigate the relationship between HRGs and the diagnosis of PE, seeking to enhance our understanding of potential molecular mechanisms and offer new perspectives for the detection and treatment of the condition. A WGCNA network was established to identify key genes significantly associated with traits of PE. LASSO, SVM-RFE, and RF were utilized to identify feature genes. Calibration curves and DCA were employed to assess the diagnostic performance of the comprehensive nomogram. Consensus clustering was applied to identify subtypes of PE. GSEA and the construction of a ceRNA network were used to explore the potential biological functions and regulatory mechanisms of the identified feature genes. Furthermore, ssGSEA was conducted to investigate the immune landscape associated with PE. We successfully identified three potential diagnostic biomarkers for PE: P4HA1, NDRG1, and BHLHE40. Furthermore, the nomogram exhibited strong diagnostic performance. In patients with PE, the abundance of pro-inflammatory immune cells was significantly elevated, reflecting characteristics of high infiltration. The levels of immune cells infiltration were significantly correlated with the expression of the identified feature genes. Notably, these feature genes may be closely linked to mitochondrial-related biological functions. In conclusion, our findings enhance the understanding of the pathological mechanisms underlying PE and open innovative avenues for the diagnosis and treatment of PE.

Simulated ischaemia/reperfusion impairs trophoblast function through divergent oxidative stress- and MMP-9-dependent mechanisms

Early-onset pre-eclampsia is believed to arise from defective placentation in the first trimester, leading to placental ischaemia/reperfusion (I/R) and oxidative stress. However, our current understanding of the effects of I/R and oxidative stress on trophoblast function is ambiguous in part due to studies exposing trophoblasts to hypoxia instead of I/R, and which report conflicting results. Here, we present a model of simulated ischaemia/reperfusion (SI/R) to recapitulate the pathophysiological events of early-onset pre-eclampsia (PE), by exposing first trimester cytotrophoblast HTR-8/SVneo cells to a simulated ischaemia buffer followed by reperfusion. We examined different ischaemia and reperfusion times and observed that 1 h ischaemia and 24 h reperfusion induced an increase in reactive oxygen species (ROS) production (P<0.0001) and oxygen consumption rate (P<0.01). SI/R-exposed trophoblast cells exhibited deficits in migration, proliferation, and invasion (P<0.01). While the deficits in migration and proliferation were rescued by antioxidants, suggesting an ROS-dependent mechanism, the loss of invasion was not affected by antioxidants, which suggests a divergent ROS-independent pathway. In line with this, we observed a decrease in MMP-9, the key regulatory enzyme necessary for trophoblast invasion (P<0.01), which was similarly unaffected by antioxidants, and pharmacological inhibition of MMP-9 replicated the phenotype of deficient invasion (P<0.01). Collectively, these data demonstrate that I/R impairs trophoblast migration and proliferation via a ROS-dependent mechanism, and invasion via an ROS-independent loss of MMP-9, disambiguating the role of oxidative stress and providing insights into the response of trophoblasts to I/R in the context of early-onset PE.

Per- and Polyfluoroalkyl Substances (PFAS) Affect Female Reproductive Health: Epidemiological Evidence and Underlying Mechanisms

PFAS (per- and polyfluoroalkyl substances) have been extensively used across numerous industries and consumer goods. Due to their high persistence and mobility, they are ubiquitous in the environment. Exposure to PFAS occurs in people via multiple pathways such as dermal contact, water supply, air inhalation, and dietary intake. Even if some PFAS are being phased out because of their persistent presence in the environment and harmful impacts on human health, mixes of replacement and legacy PFAS will continue to pollute the ecosystem. Numerous toxicological investigations have revealed harmful effects of PFAS exposure on female reproductive health, e.g., polycystic ovaries syndrome, premature ovarian failure, endometriosis, reproductive system tumors, pregnancy complications, and adverse pregnancy outcomes. Despite extensive epidemiological studies on the reproductive toxicity of PFAS, research findings remain inconsistent, and the underlying mechanisms are not well understood. In this review, we give an in-depth description of the sources and pathways of PFAS, and then review the reproductive toxicity of PFAS and its possible mechanisms.

The SIRT3/GSK-3β/GLUT4 axis might be involved in maternal hypoxia-induced skeletal muscle insulin resistance in old male rat offspring

Maternal hypoxia is strongly linked to insulin resistance (IR) in adult offspring, and altered insulin signaling for muscle glucose uptake is thought to play a central role. However, whether the SIRT3/GSK-3β/GLUT4 axis is involved in maternal hypoxia-induced skeletal muscle IR in old male rat offspring has not been investigated. Maternal hypoxia was established from Days 5 to 21 of pregnancy by continuous infusion of nitrogen and air. The biochemical parameters and levels of key insulin signaling molecules of old male rat offspring were determined through a series of experiments. Compared to the control (Ctrl) old male rat offspring group, the hypoxic (HY) group exhibited elevated fasting blood glucose (FBG) (∼30%), fasting blood insulin (FBI) (∼35%), total triglycerides (TGs), and low-density lipoprotein cholesterol (LDL-C), as well as results showing impairment in the glucose tolerance test (GTT) and insulin tolerance test (ITT). In addition, hematoxylin-eosin (HE) staining and transmission electron microscopy (TEM) revealed impaired cellular structures and mitochondria in the longitudinal sections of skeletal muscle from HY group mice, which might be associated with decreased SIRT3 expression. Furthermore, the expression of insulin signaling molecules, such as GSK-3β and GLUT4, was also altered. In conclusion, the present results indicate that the SIRT3/GSK-3β/GLUT4 axis might be involved in maternal hypoxia-induced skeletal muscle IR in old male rat offspring.

Maternal obesity and offspring neurodevelopment are associated with hypoxic gene expression in term human placenta

One third of women in the United States are affected by obesity during pregnancy. Maternal obesity (MO) is associated with an increased risk of neurodevelopmental and metabolic disorders in the offspring. The placenta, located at the maternal-fetal interface, is a key organ determining fetal development and likely contributes to programming of long-term offspring health. We profiled the term placental transcriptome in humans (pre-pregnancy BMI 35+ [MO condition] or 18.5-25 [lean condition]) using single-nucleus RNA-seq to compare expression profiles in MO versus lean conditions, and to reveal potential mechanisms underlying offspring disease risk. We recovered 62,864 nuclei of high quality from 10 samples each from the maternal-facing and fetal-facing sides of the placenta. On both sides in several cell types, MO was associated with upregulation of hypoxia response genes. On the maternal-facing side only, hypoxia gene expression was associated with offspring neurodevelopmental measures, in Gen3G, an independent pregnancy cohort with bulk placental tissue RNA-seq. We leveraged Gen3G to determine genes that correlated with impaired neurodevelopment and found these genes to be most highly expressed in extravillous trophoblasts (EVTs). EVTs further showed the strongest correlation between neurodevelopment impairment gene scores (NDIGSs) and the hypoxia gene score. We reanalyzed gene expression of cultured EVTs, and found increased NDIGSs associated with exposure to hypoxia. Among EVTs, accounting for the hypoxia gene score attenuated 44% of the association between BMI and NDIGSs. These data suggest that hypoxia in EVTs may be a key process in the neurodevelopmental programming of fetal exposure to MO.

Phenylbutyric acid inhibits hypoxia-induced trophoblast apoptosis and autophagy in preeclampsia via the PERK/ATF-4/CHOP pathway

Preeclampsia (PE) is a common pregnancy complication with a high mortality rate. Abnormally activated endoplasmic reticulum stress (ERS) is believed to be responsible for the destruction of key placental cells-trophoblasts. Phenylbutyric acid (4-PBA), an ERS inhibitor, is involved in regulating the development of ERS-related diseases. At present, how 4-PBA affects trophoblasts and its mechanisms is still unclear. In this study, PE cell models were established by stimulating HTR-8/SVneo cells with hypoxia. To verify the underlying mechanisms of 4-PBA on PE, CCT020312, an activator of PERK, was also used. The results showed that 4-PBA restored hypoxia-induced trophoblast viability, inhibited HIF-1α protein expression, inflammation, and PERK/ATF-4/CHOP pathway. Hoechst 33342 staining and flow cytometry results confirmed that 4-PBA decreased hypoxia-induced apoptosis in trophoblasts. The results of the JC-1 analysis and apoptosis initiation enzyme activity assay also demonstrated that 4-PBA inhibited apoptosis related to the mitochondrial pathway. Furthermore, by detecting autophagy in trophoblasts, an increased number of autophagic vesicles, damaged mitochondria, enhanced dansylcadaverine fluorescence, enhanced levels of autophagy proteins Beclin-1, LC3II, and decreased p62 were seen in hypoxia-stimulated cells. These changes were reversed by 4-PBA. Furthermore, it was observed that CCT020312 reversed the effects of 4-PBA on the viability, apoptosis, and autophagosome number of hypoxia-induced trophoblasts. In summary, 4-PBA reduces autophagy and apoptosis via the PERK/ATF-4/CHOP pathway and mitochondrial pathway, thereby restoring the viability of hypoxic trophoblasts. These findings provide a solid evidence base for the use of 4-PBA in PE treatment and guide a new direction for improving the outcomes of patients with PE.

Propofol Promoted the Cell Growth and Epithelial Mesenchymal Transformation of the HTR-8/SVneo Cells through Targeting the METTL3 Mediated ZEB2

Preeclampsia (PE) belongs to hypertensive disorder complicating pregnancy, which is a serious obstetric complication. Propofol is a new type of fast and short-acting general anesthetic, which has also been demonstrated to promote the cell growth recently. Therefore, this study was carried out to explore the effects of propofol on the cell growth, migration and invasion in the HTR-8/SVneo cells. The cell biological behaviors were analyzed using CCK-8, EdU, transwell assays. The relationship between METTL3 and ZEB2 was confirmed by RIP assay. Western blot and RT-qPCR assays were carried out to detect the protein and mRNA levels. The results showed that propofol enhanced the cell viability, proliferation, migration and invasion of the HTR-8/SVneo cells. Besides, METTL3 overexpression neutralized the propofol role. Furthermore, METTL3 overexpression elevated the m6A levels of ZEB2 and decreased the mRNA levels and stability of ZEB2. ZEB2 overexpression neutralized the role of METTL3 in the propofol treated HTR-8/SVneo cells. In conclusion, this study demonstrated the effects of propofol on promoting the cell growth, migration and invasion of HTR-8/SVneo cells. Mechanistically, propofol indirectly regulated ZEB2 expression by targeting METTL3 mediated m6A methylation modification.

The role of circular RNA in preeclampsia: From pathophysiological mechanism to clinical application

Preeclampsia (PE) is a common pregnancy-induced hypertension disorder that poses a significant threat to the health of pregnant women and fetuses, and has become a leading cause of maternal, fetal, and neonatal mortality. Currently, the therapy strategy for PE is mainly prevention management and symptomatic treatment, and only delivery can completely terminate PE. Therefore, a deeper understanding of the pathogenesis of PE is needed to make treatment and prevention more effective and targeted. With the deepening of molecular etiology research, circular RNAs (circRNAs) have been found to be widely involved in various processes of PE pathogenesis. As a kind of RNA with a special "head to tail" loop structure, the characteristics of circRNAs enable them to play diverse roles in the pathophysiology of PE, and can also serve as ideal biomarkers for early prediction and monitoring progression of PE. In this review, we summarized the latest research on PE-related circRNAs, trying to elucidate the unique or shared roles of circRNAs in various pathophysiological mechanisms of PE, aiming to provide a whole picture of current research on PE-related circRNAs, and extend a new perspective for the precise screening and targeted therapy of PE.

Maternal circulating miRNAs contribute to negative pregnancy outcomes by altering placental transcriptome and fetal vascular dynamics

Circulating miRNAs the in blood are promising biomarkers for predicting pregnancy complications and adverse birth outcomes. Previous work identified 11 gestationally elevated maternal circulating miRNAs (HEamiRNAs) that predicted infant growth deficits following prenatal alcohol exposure and regulated epithelial-mesenchymal transition in the placenta. Here we show that a single intravascular administration of pooled murine-conserved HEamiRNAs to pregnant mice on gestational day 10 (GD10) attenuates umbilical cord blood flow during gestation, explaining the observed intrauterine growth restriction (IUGR), specifically decreased fetal weight, and morphometric indices of cranial growth. Moreover, RNAseq of the fetal portion of the placenta demonstrated that this single exposure has lasting transcriptomic changes, including upregulation of members of the Notch pathway (Dll4, Rfng, Hey1), which is a pathway important for trophoblast migration and differentiation. Weighted gene co-expression network analysis also identified chemokine signaling, which is responsible for regulating immune cell-mediated angiogenesis in the placenta, as an important predictor of fetal growth and head size. Our data suggest that HEamiRNAs perturb the expression of placental genes relevant for angiogenesis, resulting in impaired umbilical cord blood flow and subsequently, IUGR.

Shoutai Wan regulates glycolysis imbalance at the maternal-fetal interface in threatened abortion mice

ETHNOPHARMACOLOGICAL RELEVANCE

Threatened abortion is a common disease among women of childbearing age. Its high incidence rate and unclear etiology, seriously threaten women's physical and mental health. Shoutai Wan (STW) is a traditional Chinese medicine decoction for treating abortion. It has a long history of treating threatened abortion by tonifying the kidney and calming the fetus. However, the mechanism of STW remains unclear.

AIM OF STUDY

To study the mechanism and potential benefit of STW in pregnant mice with hydrocortisone and mifepristone-induced threatened abortion.

MATERIALS AND METHODS

The STW compounds were identified using gas chromatography-mass spectrometry analysis. STW-H, STW-M, or STW-L was separately given 3 mg/ml, 1.5 mg/ml and 0.75 mg/ml STW in the morning, and 2 mg/ml hydrocortisone in the afternoon from gestation day (D) 1-9 and once with 0.4 mg/kg mifepristone on D10. Didroxyprogesterone (0.1 mg/ml) and equal dose pure water were used to replace STW in didroxyprogesterone (DYD) group and model group respectively. The control group used pure water to replace STW, hydrocortisone, and mifepristone. We performed morphological and histological analyses of the maternal-fetal interface on day 10.

RESULTS

The embryo loss rate in the STW-H and DYD groups was lower than that in the model group. Hematoxylin and eosin (HE) staining suggested that the morphology of maternal-fetal interface was improved in the STW-H and DYD groups. Immunohistochemical (IHC), Quantitative Reverse Transcription Polymerase Chain Reactionstaining (qRT-PCR), and Western blot (WB) results indicated that HIF-1α expression in the maternal-fetal interface of the STW-H and DYD groups was higher than that in model group. The activities of HK, PKM, LDH and the concentration of lactic acid in the STW-H and DYD groups were higher than those in model group. Furthermore, the protein and mRNA levels of HK2, PKM2, LDHA, MCT4, and GPR81 were higher in the STW-H and DYD groups than those in the model group.

CONCLUSIONS

STW can reduce the pregnancy loss rate by regulating the glycolysis balance at the maternal-fetal interface of kidney deficiency threatened abortion model mice.

Identification of LncRNA-miRNA-mRNA ceRNA network in hypoxia-induced HTR-8/SVneo cells for preeclampsia

Preeclampsia (PE) is a common pregnancy complication, and placental hypoxia is one of its causes. We aimed to identify the transcriptional profile and construct a long non-coding RNAs (lncRNA)-centered competing endogenous RNAs (ceRNA) network in hypoxia-induced HTR8/SVneo cells. We used datasets from the GEO database to identify important pathways in PE. We performed microarray profiling and functional analysis to identify differentially expressed long non-coding RNAs (lncRNAs), differentially expressed profiles of microRNA (miRNAs), and differentially expressed profiles of messenger RNA (mRNAs) in hypoxia-induced HTR8/SVneo cells. The candidates were validated using quantitative reverse transcription polymerase chain reaction. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses were performed to understand the functional significance of differentially expressed genes. Finally, we constructed an lncRNA-centered ceRNA network. Several hub genes were validated both in placentas from PE and normal pregnancy, and in hypoxia-induced HTR8/SVneo cells. The hypoxic response pathway was involved in the pathophysiology of PE. Subsequently, we identified 536 differentially expressed profiles of lncRNAs (183 upregulated and 353 downregulated), 46 differentially expressed profiles of miRNAs (35 upregulated and 11 downregulated), and 2782 differentially expressed profiles of mRNAs (DEmRNAs) (1031 upregulated and 1751 downregulated) in hypoxia-induced HTR8/SVneo cells. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed potential pathways affected by these genes, such as angiogenesis, the HIF-1 signaling pathway, and the PI3K-Akt signaling pathway. The ceRNA network comprised 35 lncRNAs, 11 miRNAs, 27 mRNAs, and 2 hub lncRNAs, which might play a vital role in placental functions and PE. Our results revealed the transcriptome profile and constructed an lncRNA-centered ceRNA network in hypoxia-induced HTR8/SVneo cells, thereby providing potential therapeutic targets for PE.

Human Chorionic Villous Differentiation and Placental Development

In humans, the placenta provides the only fetomaternal connection and is essential for establishing a pregnancy as well as fetal well-being. Additionally, it allows maternal physiological adaptation and embryonic immunological acceptance, support, and nutrition. The placenta is derived from extra-embryonic tissues that develop rapidly and dynamically in the first weeks of pregnancy. It is primarily composed of trophoblasts that differentiate into villi, stromal cells, macrophages, and fetal endothelial cells (FEC). Placental differentiation may be closely related to perinatal diseases, including fetal growth retardation (FGR) and hypertensive disorders of pregnancy (HDP), and miscarriage. There are limited findings regarding human chorionic villous differentiation and placental development because conducting in vivo studies is extremely difficult. Placental tissue varies widely among species. Thus, experimental animal findings are difficult to apply to humans. Early villous differentiation is difficult to study due to the small tissue size; however, a detailed analysis can potentially elucidate perinatal disease causes or help develop novel therapies. Artificial induction of early villous differentiation using human embryonic stem (ES) cells/induced pluripotent stem (iPS) cells was attempted, producing normally differentiated villi that can be used for interventional/invasive research. Here, we summarized and correlated early villous differentiation findings and discussed clinical diseases.

Gamma Secretase Inhibitors as Potential Therapeutic Targets for Notch Signaling in Uterine Leiomyosarcoma

Uterine leiomyosarcoma (uLMS) is a rare and aggressive cancer with few effective therapeutics. The Notch signaling pathway is evolutionarily conserved with oncogenic properties, but it has not been well studied in uLMS. The purpose of our study was to determine expression of Notch family genes and proteins and to investigate the therapeutic effect of γ-secretase inhibitors (GSIs), indirect inhibitors of Notch signaling, in uLMS. We determined expression of Notch genes and proteins in benign uterine smooth muscle tissue, fibroids, and uLMS samples by immunostaining and in two uLMS cell lines, SK-UT-1B (uterine primary) and SK-LMS-1 (vulvar metastasis) by RT-PCR, Western blot and immunostaining. We exposed our cell lines to GSIs, DAPT and MK-0752, and measured expression of HES1, a downstream effector of Notch. Notch proteins were differentially expressed in uLMS. Expression of NOTCH3 and NOTCH4 was higher in uLMS samples than in benign uterine smooth muscle and fibroids. Expression of NOTCH4 was higher in SK-LMS-1 compared to SK-UT-1B. Exposure of SK-UT-1B and SK-LMS-1 to DAPT and MK-0752 decreased expression of HES1 and decreased uLMS cell viability in a dose- and time-dependent manner that was unique to each GSI. Our findings suggest that GSIs are potential therapeutics for uLMS, albeit with limited efficacy.

Whole transcriptome analysis of trophoblasts under hypoxia

INTRODUCTION

A physiological hypoxia environment exists at maternal-fetal interface during early pregnancy. In addition, there is a pathological hypoxic microenvironment in patients with preeclampsia. Therefore, investigating the hypoxic adaptation and the effects of hypoxia on trophoblasts transcriptome is helpful to better understand the function and regulatory mechanism of trophoblasts at the maternal-fetal interface.

METHODS

Trophoblast cell line HTR-8/SVneo was cultured under normoxia and hypoxia for 24 h, the full transcriptome was analyzed via RNA-Seq. GO and KEGG enrichment were performed on differentially expressed mRNA, adjacent genes of differentially expressed lncRNA, host genes of differentially expressed circRNA and target genes of differential expressed miRNA.

RESULTS

The results showed that hypoxia differentially regulated 373 mRNAs, 334 lncRNAs, 71 circRNAs and 33 miRNAs. GO and KEGG enrichment showed that hypoxia negatively regulated TLR3 and PI3K-Akt signaling pathways. Consistently, we found hypoxia significantly inhibited TLR3 agonist-induced cytokines expression and the phosphorylation of Akt and mTOR.

DISCUSSION

Our study obtained the full transcriptome data and potential regulatory network of trophoblasts under hypoxia, providing supportive data for revealing the function of trophoblasts.