Hippo-YAP1 signaling pathway and severe preeclampsia (sPE) in the Chinese population

Non-invasive prediction of preeclampsia using the maternal plasma cell-free DNA profile and clinical risk factors

Background

Preeclampsia (PE) is a pregnancy complication defined by new onset hypertension and proteinuria or other maternal organ damage after 20 weeks of gestation. Although non-invasive prenatal testing (NIPT) has been widely used to detect fetal chromosomal abnormalities during pregnancy, its performance in combination with maternal risk factors to screen for PE has not been extensively validated. Our aim was to develop and validate classifiers that predict early- or late-onset PE using the maternal plasma cell-free DNA (cfDNA) profile and clinical risk factors.

Methods

We retrospectively collected and analyzed NIPT data of 2,727 pregnant women aged 24-45 years from four hospitals in China, which had previously been used to screen for fetal aneuploidy at 12 + 0 ~ 22 + 6 weeks of gestation. According to the diagnostic criteria for PE and the time of diagnosis (34 weeks of gestation), a total of 143 early-, 580 late-onset PE samples and 2,004 healthy controls were included. The wilcoxon rank sum test was used to identify the cfDNA profile for PE prediction. The Fisher's exact test and Mann-Whitney U-test were used to compare categorical and continuous variables of clinical risk factors between PE samples and healthy controls, respectively. Machine learning methods were performed to develop and validate PE classifiers based on the cfDNA profile and clinical risk factors.

Results

By using NIPT data to analyze cfDNA coverages in promoter regions, we found the cfDNA profile, which was differential cfDNA coverages in gene promoter regions between PE and healthy controls, could be used to predict early- and late-onset PE. Maternal age, body mass index, parity, past medical histories and method of conception were significantly differential between PE and healthy pregnant women. With a false positive rate of 10%, the classifiers based on the combination of the cfDNA profile and clinical risk factors predicted early- and late-onset PE in four datasets with an average accuracy of 89 and 80% and an average sensitivity of 63 and 48%, respectively.

Conclusion

Incorporating cfDNA profiles in classifiers might reduce performance variations in PE models based only on clinical risk factors, potentially expanding the application of NIPT in PE screening in the future.

Association of MST1 in the First Trimester of Pregnancy with Gestational Diabetes Mellitus and Adverse Pregnancy Outcomes

Aim

We investigate the association of mammalian sterile line 20-like kinase 1 (MST1) in the first trimester with the risks of gestational diabetes mellitus (GDM) and adverse pregnancy outcomes.

Methods

Pregnancies were recruited during their first antenatal care visit between 8 and 12 gestational weeks. These pregnancies underwent an oral glucose tolerance test between 24 and 28 gestational weeks and were followed up until delivery. Serum MST1 levels at 8-12 gestational weeks and 24-28 gestational weeks were measured using an enzyme-linked immunosorbent assay (ELISA) kit. Logistic regression models were used to evaluate the association between MST1 levels in the first trimester and the risks of GDM and adverse pregnancy outcomes.

Results

This cohort study enrolled a total of 231 pregnancies. GDM was present in 42 (18.18%) women. Compared to the normal glucose tolerance (NGT) group, the GDM group had higher levels of FPG, HOMA-IR, and MST1 both in the first and second trimesters, but had lower HOMA-β levels only in the second trimester. Then participants were classified according to the median MST1 value in the first trimester. Incidences of GDM, composite adverse pregnancy outcomes, preterm birth, and macrosomia increased in women with higher MST1 values. Serum MST1 in the first trimester was correlated with FPG, 1hr PG, 2hr PG, and HOMA-IR, while inversely correlated with HOMA-β in the second trimester. Furthermore, after adjusting for traditional risk factors, women with higher first-trimester MST1 values had greater odds of GDM, composite adverse pregnancy outcomes, preterm birth, and macrosomia (aOR 2.276, P=0.030; aOR 2.690, P=0.003; aOR 3.210, P=0.048; aOR 5.488, P=0.010).

Conclusion

Elevated levels of MST1 in the first trimester of pregnancies are associated with increased risks of GDM and adverse pregnancy outcomes.

YAP-mediated trophoblast dysfunction: the common pathway underlying pregnancy complications

Yes-associated protein (YAP) is a pivotal regulator in cellular proliferation, survival, differentiation, and migration, with significant roles in embryonic development, tissue repair, and tumorigenesis. At the maternal-fetal interface, emerging evidence underscores the importance of precisely regulated YAP activity in ensuring successful pregnancy initiation and progression. However, despite the established association between YAP dysregulation and adverse pregnancy outcomes, insights into the impact of aberrant YAP levels in fetal-derived, particularly trophoblast cells, and the ensuing dysfunction at the maternal-fetal interface remain limited. This review comprehensively examines YAP expression and its regulatory mechanisms in trophoblast cells throughout pregnancy. We emphasize its integral role in placental development and maternal-fetal interactions and delve into the correlations between YAP dysregulation and pregnancy complications. A nuanced understanding of YAP's functions during pregnancy could illuminate intricate molecular mechanisms and pave the way for innovative prevention and treatment strategies for pregnancy complications. Video Abstract.

Control of stem cell renewal and fate by YAP and TAZ

Complex physiological processes control whether stem cells self-renew, differentiate or remain quiescent. Two decades of research have placed the Hippo pathway, a highly conserved kinase signalling cascade, and its downstream molecular effectors YAP and TAZ at the nexus of this decision. YAP and TAZ translate complex biological cues acting on stem cells - from mechanical forces to cellular metabolism - into genome-wide effects to mediate stem cell functions. While aberrant YAP/TAZ activity drives stem cell dysfunction in ageing, tumorigenesis and disease, therapeutic targeting of Hippo signalling and YAP/TAZ can boost stem cell activity to enhance regeneration. In this Review, we discuss how YAP/TAZ control the self-renewal, fate and plasticity of stem cells in different contexts, how dysregulation of YAP/TAZ in stem cells leads to disease, and how therapeutic modalities targeting YAP/TAZ may benefit regenerative medicine and cancer therapy.

Trophoblast Cell Function in the Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a complex thrombo-inflammatory autoimmune disease characterized by the presence of antiphospholipid antibodies (aPL). Women with APS are at high risk of recurrent early pregnancy loss as well as late obstetrical complications-premature birth due to placental insufficiency or severe preeclampsia. Accumulating evidence implies that vascular thrombosis is not the only pathogenic mechanism in obstetric APS, and that the direct negative effect of aPL on the placental cells, trophoblast, plays a major role. In this review, we summarize the current findings regarding the potential mechanisms involved in aPL-induced trophoblast dysfunction. Introduction on the APS and aPL is followed by an overview of the effects of aPL on trophoblast-survival, cell function and aPL internalization. Finally, the implication of several non-coding RNAs in pathogenesis of obstetric APS is discussed, with special emphasis of their possible role in trophoblast dysfunction and the associated mechanisms.

Microarray expression results of VEGF, YAP1 and PTEN immunostains in preeclampsia cases

We aimed to evaluate the expression of YAP1, PTEN, VEGF in the placentas of patients with preeclampsia and placentas of healthy pregnant women for trophoblast invasion, which is similar to cancer etiopathogenesis. The placentas of 70 women who gave birth, including 30 preeclampsia and 40 healthy controls, were evaluated. YAP1, PTEN and VEGF immunohistochemical staining were performed using the microarray method on placental tissue. The mean ± standard deviation for YAP1, PTEN and VEGF intensity were; 1.57 ± 0.71,2.59 ± 0.80, 1.61 ± 0.59, respectively. PTEN intensity was statistically significantly lower in the preeclampsia group than in the control group (2.37 ± 0.99 vs 2.75 ± 0.58, p = .049). There was no difference between the groups in terms of YAP1 and VEGF staining (p > .05). The etiopathogenesis of preeclampsia is still unclear. However, since trophoblast invasion and endothelial repair have similar aspects with cancer mechanisms, both preeclampsia and cancer studies are progressing by supporting each other. Our study is a prototype study showing that large-participation studies can be carried out easily by using the microarray method as an economic model.

Inactivation of Yes-Associated Protein Mediates Trophoblast Dysfunction: A New Mechanism of Pregnancy Loss Associated with Anti-Phospholipid Antibodies?

Pregnancy morbidity induced by anti-phospholipid antibodies (aPL+/PM+) is mainly thought to arise from placental abnormalities. We attempted to investigate the effect of aPL on the activity of Yes-associated protein (YAP) in the trophoblast and how YAP regulated human trophoblasts function. Thus, HTR-8 cells were treated with IgG purified from aPL+/PM+ women or normal controls. We found that aPL+/PM+ IgG impacted YAP activity via abrogating YAP expression. Further investigation of the anti-β2GPI-IgG/β2GPI complex showed an inhibition of nuclear YAP level and translocation in a dose-dependent manner, which might be rescued by progesterone in HTR-8 cells. YAP overexpression or knockdown HTR-8 cells were established for the evaluation of cell function and related gene expression in vitro. Loss of YAP arrested cell cycles in the G2/M phase, accelerated cell apoptosis by increasing the ratio of Bax/Bcl2, and disrupted MMP2/9-mediated cell migration and angiogenesis tube formation by VEGF. These findings support a new mechanism of PM associated with aPL through which YAP inactivation induced by aPL perturbs the trophoblast cell cycle, apoptosis, migration, and angiogenesis, finally developing into pregnancy failure.

Two-Dimensional Ultrasound and Triplane Tissue Doppler Ultrasound of Patients with Severe Preeclampsia

This study was to investigate the cardiac function characteristics under two-dimensional ultrasound and triplane tissue Doppler imaging (TDI) of patients with severe preeclampsia (SPE). 28 SPE patients with singleton pregnancy from January 2018 to December 2020 were included in the SPE group. 25 healthy nonpregnant women of reproductive age were taken as the control group (Ctrl group), and 26 normal pregnant women with singleton pregnancy were selected as the normal group (Norm group); all the research objects underwent ultrasonography. The morphological and functional indexes of left and right ventricles were compared among the cases in different groups. The results showed that the left ventricular end-diastolic period diameter (LVEDd), left ventricular relative wall thickness (LV-RWT), left ventricular mass index (LVMi), left anterior descending (LAd), left ventricular $E/e$ and $e/a$ values, right ventricular diameter (RV-D), right ventricular anterior wall thickness (RVAW), $a$ value, right atrial septum (RA-S), pulmonary artery systolic pressure (PASP), left ventricular end-systolic period diameter (LVEds), interventricular septal thickness (IVSd), posterior wall thickness (PWd), end-diastolic period volume (EVD), end-systolic period volume (ESV), relative wall thickness (RWT), sphericity index (SpI), left atrium volume index (LAVi), and $E/e$ value of patients in the SPE group were higher than those in the Ctrl group and the Norm group ( $P<0.05$ ). The mitral annular plane systolic excursion (MAPSE), $s$ value, tricuspid annual plane systolic excursion (TAPSE), ratio of early diastolic blood flow velocity to late diastolic blood flow velocity ( $E/A$ ), ratio of peak early diastolic velocity to peak late diastolic velocity ( $e/a$ ), peak early diastolic velocity ( $e$ ), and ejection fraction (EF) of the SPE group were lower than those of the Ctrl group and the Norm group ( $P<0.05$ ). The ratio of mitral valve early diastolic blood flow velocity to peak early diastolic velocity ( $E/e$ ) of the Norm group was higher than that of the Ctrl group ( $P<0.05$ ). In two-dimensional ultrasound of the SPE group, the maximum difference in time from the start to the peak of systole (Ts) of the right ventricle between the basal and middle segments of the lateral wall and that of interventricular septum (RV-Ts-max) was $31.56\pm 0.39\%$ . The maximum difference in time to peak of early diastole (Te) under the same condition (RV-Te-max) was $47.16\pm 0.19\%$ . Left ventricular LV-Ts-max and LV-Te-max were $9.83\pm 0.80\%$ and $8.37\pm 0.68\%$ , respectively, in triplane TDI, which were considerably higher than those in the Ctrl and Norm groups ( $P<0.05$ ). It suggested that two-dimensional ultrasound and triplane TDI could reflect the ventricular morphology as well as diastolic and systolic function injury in patients, which offered a reference basis for the diagnosis of SPE.

Molecular regulation of trophoblast stem cell self-renewal and giant cell differentiation by the Hippo components YAP and LATS1

Background

Trophoblast stem cells (TSCs), the precursors of trophoblast cells of placenta, possess the potential to differentiate into various trophoblastic subtypes in vitro. Establishment of extraembryonic trophoblastic lineage is preceded by the “outside versus inside” positional information in preimplantation embryos, critically synchronized by the Hippo components. Abundant expression of Hippo effector YAP in TSCs and differentiated cells with paucity of information on Hippo regulation of TSC proliferation/differentiation led us test the hypothesis that Hippo dynamics is one of the regulators of  TSC proliferation/differentiation.

Methods

Blastocyst-derived murine TSCs were used. Dynamics of Hippo components were analyzed using immunofluorescence, western blotting, immunoprecipitation, qRT-PCR. Interaction studies were performed using full-length and deletion constructs. BrdU incorporation assay, flow cytometry-based polyploidy analysis and confocal microscopy were used to decipher the underlying mechanism.

Results

YAP translocates to the nucleus in TSCs and utilizes its WW₂ domain to interact with the PPQY motif of the stemness factor, CDX2. YAP limits TSC proliferation with associated effect on CDX2 target CyclinD1. Trophoblast giant cells (TGC) differentiation is associated with cytoplasmic retention of YAP, heightened pYAP^Ser127, decrease in the level of the core Hippo component, LATS1, which thereby impedes LATS1-LIMK2 association. Decreased LATS1-LIMK2 complex formation in TGCs was associated with elevated pLIMK2^Thr505 as well as its target pCOFILIN^Ser3. Precocious overexpression of LATS1 during trophoblast differentiation decreased TGC marker, Prl2c2, diminished pLIMK2^Thr505 and inactive COFILIN (pCOFILIN^Ser3) while COFILIN-phosphatase, CHRONOPHIN remained unchanged. LATS1 overexpression inhibited trophoblast endoreduplication with smaller-sized TGC-nuclei, lower ploidy level and disintegrated actin filaments. Inhibition of LIMK2 activity recapitulated the effects of LATS1 overexpression in trophoblast cells.

Conclusion

These results unveil a multilayered regulation of trophoblast self-renewal and differentiation by the Hippo components.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02844-w.

MiR-326 inhibits trophoblast growth, migration, and invasion by targeting PAX8 via Hippo pathway

Preeclampsia (PE), a pregnancy disorder that affects 5-7% of pregnant women, is among the primary causes for maternal and perinatal mortality. PE is believed to be associated with insufficient invasion of villous and extravillous trophoblasts (EVTs), which hampers uterine spiral artery remodeling and finally induces PE. But the mechanism responsible for reduction of trophoblast invasion remains unclear. In this study, placental tissues taken from healthy donors and PE patients were used to evaluate the miR-326 expression; CCK8 and colony formation assays were used to confirm the effect of miR-326 on cell proliferation; transwell assay was used to demonstrate the effect of miR-326 on cell invasion capability; western blot was used to investigate the underlying mechanism; and luciferase assay was used to detect the effect of miR-326 on YAP/TAZ-mediated transcription activity. It was revealed the miR-326 expression was higher in placentas from PE patients than from healthy donors. After transfection of miR-326 mimics, trophoblast proliferation and invasion were impaired. Using TargetScan, we speculated that PAX8 was a target of miR-326, which was later confirmed by western blot. The YAP/TAZ expression was also downregulated after transfection with miR-326. Luciferase assay demonstrated that overexpression of miR-326 suppressed YAP/TAZ-mediated transcription activity by targeting PAX8. Overexpression of PAX8 could partly rescue miR-326-induced suppression of trophoblast proliferation and invasion. Taken together, our result indicated that miR-326 suppresses trophoblast growth, invasion, and migration by means of targeting PAX8 via the Hippo pathway.

Impaired Sphingosine-1-Phosphate Synthesis Induces Preeclampsia by Deactivating Trophoblastic YAP (Yes-Associated Protein) Through S1PR2 (Sphingosine-1-Phosphate Receptor-2)-Induced Actin Polymerizations

Incomplete spiral artery remodeling, caused by impaired extravillous trophoblast invasion, is a fundamental pathogenic process associated with malplacentation and the development of preeclampsia. Nevertheless, the mechanisms controlling this regulation of trophoblast invasion are largely unknown. We report that sphingosine-1-phosphate synthesis and expression is abundant in healthy trophoblast, whereas in pregnancies complicated by preeclampsia the placentae are associated with reduced sphingosine-1-phosphate and lower SPHK1 (sphingosine kinase 1) expression and activity. In vivo inhibition of sphingosine kinase 1 activity during placentation in pregnant mice led to decreased placental sphingosine-1-phosphate production and defective placentation, resulting in a preeclampsia phenotype. Moreover, sphingosine-1-phosphate increased HTR8/SVneo (immortalized trophoblast cells) cell invasion in a Hippo-signaling-dependent transcriptional coactivator YAP (Yes-associated protein) dependent manner, which is activated by S1PR2 (sphingosine-1-phosphate receptor-2) and downstream RhoA/ROCK induced actin polymerization. Mutation-based YAP-5SA demonstrated that sphingosine-1-phosphate activation of YAP could be either dependent or independent of Hippo signaling. Together, these findings suggest a novel pathogenic pathway of preeclampsia via disrupted sphingosine-1-phosphate metabolism and signaling-induced, interrupted actin dynamics and YAP deactivation; this may lead to potential novel intervention targets for the prevention and management of preeclampsia.

Early Pregnancy Exposure to Ambient Air Pollution among Late-Onset Preeclamptic Cases Is Associated with Placental DNA Hypomethylation of Specific Genes and Slower Placental Maturation

Exposure to ambient air pollution during pregnancy has been associated with an increased risk of preeclampsia (PE). Some suggested mechanisms behind this association are changes in placental DNA methylation and gene expression. The objective of this study was to identify how early pregnancy exposure to ambient nitrogen oxides (NO_x) among PE cases and normotensive controls influence DNA methylation (EPIC array) and gene expression (RNA-seq). The study included placentas from 111 women (29 PE cases/82 controls) in Scania, Sweden. First-trimester NO_x exposure was assessed at the participants’ residence using a dispersion model and categorized via median split into high or low NO_x. Placental gestational epigenetic age was derived from the DNA methylation data. We identified six differentially methylated positions (DMPs, q < 0.05) comparing controls with low NO_x vs. cases with high NO_x and 14 DMPs comparing cases and controls with high NO_x. Placentas with female fetuses showed more DMPs (N = 309) than male-derived placentas (N = 1). Placentas from PE cases with high NO_x demonstrated gestational age deceleration compared to controls with low NO_x (p = 0.034). No differentially expressed genes (DEGs, q < 0.05) were found. In conclusion, early pregnancy exposure to NO_x affected placental DNA methylation in PE, resulting in placental immaturity and showing sexual dimorphism.

G protein-coupled estrogen receptor stimulates human trophoblast cell invasion via YAP-mediated ANGPTL4 expression

Insufficient invasion of trophoblast cells into the uterine decidua is associated with preeclampsia (PE). G protein-coupled estrogen receptor (GPER) is a membrane estrogen receptor involved in non-genomic estrogen signaling. GPER is expressed in human trophoblast cells and downregulated GPER levels are noted in PE. However, to date, the role of GPER in trophoblast cells remains largely unknown. Here, we applied RNA sequencing (RNA-seq) to HTR-8/SVneo human trophoblast cells in response to G1, an agonist of GPER, and identified angiopoietin-like 4 (ANGPTL4) as a target gene of GPER. Treatment of trophoblast cells with G1 or 17β-estradiol (E2) activated Yes-associated protein (YAP), the major downstream effector of the Hippo pathway, via GPER but in a mammalian STE20-like protein kinase 1 (MST1)-independent manner. Using pharmacological inhibitors as well as loss- and gain-of-function approaches, our results revealed that YAP activation was required for GPER-stimulated ANGPTL4 expression. Transwell invasion assays demonstrated that activation of GPER-induced ANGPTL4 promoted cell invasion. In addition, the expression levels of GPER, YAP, and ANGPTL4 were downregulated in the placenta of patients with PE. Our findings reveal a mechanism by which GPER exerts its stimulatory effect on human trophoblast cell invasion by upregulating YAP-mediated ANGPTL4 expression.

Cheng, Fan, Li et al. identified ANGPTL4 as a G1-induced target gene of GPER/YAP in HRT8 cells using RNA-seq and highlighted its importance in regulating trophoblast cell invasion. The authors also reported GPER downregulation in the placenta and lower estradiol levels in patients who developed preeclampsia.

Integrated bioinformatics analysis reveals novel key biomarkers and potential candidate small molecule drugs in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is the metabolic disorder that appears during pregnancy. The current investigation aimed to identify central differentially expressed genes (DEGs) in GDM. The transcription profiling by array data (E-MTAB-6418) was obtained from the ArrayExpress database. The DEGs between GDM samples and non-GDM samples were analyzed. Functional enrichment analysis were performed using ToppGene. Then we constructed the protein–protein interaction (PPI) network of DEGs by the Search Tool for the Retrieval of Interacting Genes database (STRING) and module analysis was performed. Subsequently, we constructed the miRNA–hub gene network and TF–hub gene regulatory network. The validation of hub genes was performed through receiver operating characteristic curve (ROC). Finally, the candidate small molecules as potential drugs to treat GDM were predicted by using molecular docking. Through transcription profiling by array data, a total of 869 DEGs were detected including 439 up-regulated and 430 down-regulated genes. Functional enrichment analysis showed these DEGs were mainly enriched in reproduction, cell adhesion, cell surface interactions at the vascular wall and extracellular matrix organization. Ten genes, HSP90AA1, EGFR, RPS13, RBX1, PAK1, FYN, ABL1, SMAD3, STAT3 and PRKCA were associated with GDM, according to ROC analysis. Finally, the most significant small molecules were predicted based on molecular docking. This investigation identified hub genes, signal pathways and therapeutic agents, which might help us, enhance our understanding of the mechanisms of GDM and find some novel therapeutic agents for GDM.

Context-dependent roles of YAP/TAZ in stem cell fates and cancer

Hippo effectors YAP and TAZ control cell fate and survival through various mechanisms, including transcriptional regulation of key genes. However, much of this research has been marked by conflicting results, as well as controversy over whether YAP and TAZ are redundant. A substantial portion of the discordance stems from their contradictory roles in stem cell self-renewal vs. differentiation and cancer cell survival vs. apoptosis. In this review, we present an overview of the multiple context-dependent functions of YAP and TAZ in regulating cell fate decisions in stem cells and organoids, as well as their mechanisms of controlling programmed cell death pathways in cancer.