United we stand not dividing: The syncytiotrophoblast and cell senescence

Placental co-transcriptional activator Vestigial-like 1 (VGLL1) drives tumorigenesis via increasing transcription of proliferation and invasion genes

Introduction

Vestigial-like 1 (VGLL1) is a co-transcriptional activator that binds to TEA domain-containing transcription factors (TEADs). Its expression is upregulated in a variety of aggressive cancer types, including pancreatic and basal-like breast cancer, and increased transcription of VGLL1 is strongly correlated with poor prognosis and decreased overall patient survival. In normal tissues, VGLL1 is most highly expressed within placental trophoblast cells, which share the common attributes of rapid cellular proliferation and invasion with tumor cells. The impact of VGLL1 in cancer has not been fully elucidated and no VGLL1-targeted therapy currently exists.

Methods

The aim of this study was to evaluate the cellular function and downstream genomic targets of VGLL1 in placental, pancreatic, and breast cancer cells. Functional assays were employed to assess the role of VGLL1 in cellular invasion and proliferation, and ChIP-seq and RNAseq assays were performed to identify VGLL1 target genes and potential impact using pathway analysis.

Results

ChIP-seq analysis identified eight transcription factors with a VGLL1-binding motif that were common between all three cell types, including TEAD1-4, AP-1, and GATA6, and revealed ~3,000 shared genes with which VGLL1 interacts. Furthermore, increased VGLL1 expression led to an enhancement of cell invasion and proliferation, which was supported by RNAseq analysis showing transcriptional changes in several genes known to be involved in these processes.

Discussion

This work expands our mechanistic understanding of VGLL1 function in tumor cells and provides a strong rationale for developing VGLL1-targeted therapies for treating cancer patients.

Fetal growth at term and placental oxidative stress in a tissue micro-array model: a histological and immunohistochemistry study

This study examines 8-hydroxyguanine (8-oxo-Gua) staining in placental tissue samples based on fetal size at birth as well as its relationships with placental histology and other pregnancy variables. This prospective cohort study included women > 18 years with a singleton pregnancy, a live fetus, fluency in Italian, and delivery at term. A total of 165 pregnancies were included in the study. The nuclear syncytiotrophoblast 8-oxo-Gua staining score in LGA was substantially greater than in late FGR (p < 0.05), although the cytoplasm score was lower in SGA and LGA than in AGA (p < 0.05). Furthermore, a sex-specific pattern of 8-oxo-Gua staining was discovered in single-term placentas, with more oxidative damage found in the nuclei of syncytiotrophoblast cells and stromal and endothelial cells in AGA males compared to AGA females (p < 0.05). Second, the histological pattern of late FGR placentae differed by gender. Finally, a significant correlation (p < 0.05) was found between high-intensity 8-oxo-Gua staining in the cytoplasm of syncytiotrophoblast cells and thrombi in the chorionic plate or villi in males. On the other hand, female fetuses demonstrated a significant connection (p < 0.05) between high-intensity 8-oxo-Gua staining in endothelial and stromal cells and high birthweight MoM values. Our findings indicated a significant variation in the oxidative stress pattern between male and female placentae, implying that fetal growth is regulated differently in the two sexes.

Regulators involved in trophoblast syncytialization in the placenta of intrauterine growth restriction

Placental dysfunction refers to the insufficiency of placental perfusion and chronic hypoxia during early pregnancy, which impairs placental function and causes inadequate supply of oxygen and nutrients to the fetus, affecting fetal development and health. Fetal intrauterine growth restriction, one of the most common outcomes of pregnancy-induced hypertensions, can be caused by placental dysfunction, resulting from deficient trophoblast syncytialization, inadequate trophoblast invasion and impaired vascular remodeling. During placental development, cytotrophoblasts fuse to form a multinucleated syncytia barrier, which supplies oxygen and nutrients to meet the metabolic demands for fetal growth. A reduction in the cell fusion index and the number of nuclei in the syncytiotrophoblast are found in the placentas of pregnancies complicated by IUGR, suggesting that the occurrence of IUGR may be related to inadequate trophoblast syncytialization. During the multiple processes of trophoblasts syncytialization, specific proteins and several signaling pathways are involved in coordinating these events and regulating placental function. In addition, epigenetic modifications, cell metabolism, senescence, and autophagy are also involved. Study findings have indicated several abnormally expressed syncytialization-related proteins and signaling pathways in the placentas of pregnancies complicated by IUGR, suggesting that these elements may play a crucial role in the occurrence of IUGR. In this review, we discuss the regulators of trophoblast syncytialization and their abnormal expression in the placentas of pregnancies complicated by IUGR.

The intricate nature of senescence in development and cell plasticity

Cellular senescence, a stable form of cell cycle arrest, accompanied by pronounced secretory activity, has functional roles in both physiological and pathological conditions. Although senescence has been linked for a long time with cancer and ageing, recent studies have revealed a functional role of senescence in development, regeneration and reprogramming. Notably, the transient presence of senescent cells may be beneficial, in contrast to the potential deleterious effects of persistent senescence in aged or chronically damaged tissues. We will discuss how senescence contributes to embryonic development, cell plasticity and tissue regeneration, as a highly coordinated and programmed cellular state.

Oxidative stress, lipid peroxidation and premature placental senescence in preeclampsia

Accelerated placental senescence is associated with preeclampsia (PE) and other pregnancy complications. It is characterized by an accelerated decline in placental function due to the accumulation of senescence patterns such as telomere shortening, mitochondrial dysfunction, oxidative damages, increased expression of phosphorylated (serine-139) histone γ-H2AX, a sensitive marker of double-stranded DNA breaks, accumulation of cross-linked ubiquitinated proteins and sirtuin inhibition. Among the lipid oxidation products generated by the peroxidation of polyunsaturated fatty acids, aldehydes such as acrolein, 4-hydroxy-2-nonenal, 4-oxo-2-nonenal, are present in the blood and placenta from PE-affected women and could contribute to PE pathogenesis and accelerated placental aging. In this review we summarize the current knowledge on premature placental senescence and the role of oxidative stress and lipid oxidation-derived aldehydes in this process, as well as their links with PE pathogenesis. The interest of developing (or not) new therapeutic strategies targeting lipid peroxidation is discussed, the objective being a better understanding of accelerated placental aging in PE pathophysiology, and the prevention of PE bad outcomes.

Decreased expression of caveolin-1 have relevance to promoted senescence in preeclamptic placenta

OBJECTIVES

To assess the association between altered expression of caveolin-1 and p53/p21, as indicatives of cellular senescence, in preeclamptic placenta.

STUDY DESIGN

Placental tissues and serum were collected from rats (Sham and reduced uterine perfusion pressure group) at 18.5 days post coitum and humans (normotensive pregnant and preeclampsia groups). The concentration and expression of caveolin-1 were measured in the collected tissues, and the correlation between p53 and p21 expression was evaluation.

MAIN OUTCOME MEASURES

Placental mRNA expression and serum concentration of caveolin-1 were measured using qRT-PCR and ELISA, respectively. Altered expressions of caveolin-1 and p53/p21 were revealed and quantified by immunohistochemistry. The association between these changes was investigated using correlation analysis.

RESULTS

Placental mRNA expressions and serum concentrations of caveolin-1 were significantly decreased in reduced uterine perfusion pressure and preeclampsia groups. The expressions of caveolin-1 and p53/ p21 were significantly altered in placenta complicated with preeclampsia. Correlation analysis revealed a significant inverse association between changes in caveolin-1 and p53/p21. Subsequently, these results were obtained by investigating the preeclampsia onset time.

CONCLUSION

These results revealed that the expression of caveolin-1 profoundly decreases in the placenta and serum of preeclampsia. These factors contribute to the mechanism of accelerated cellular senescence in placenta, which is one of the various etiologies of preeclampsia.

YAP1 nuclear efflux and transcriptional reprograming follow membrane diminution upon VSV-G-induced cell fusion

Cells in many tissues, such as bone, muscle, and placenta, fuse into syncytia to acquire new functions and transcriptional programs. While it is known that fused cells are specialized, it is unclear whether cell-fusion itself contributes to programmatic-changes that generate the new cellular state. Here, we address this by employing a fusogen-mediated, cell-fusion system to create syncytia from undifferentiated cells. RNA-Seq analysis reveals VSV-G-induced cell fusion precedes transcriptional changes. To gain mechanistic insights, we measure the plasma membrane surface area after cell-fusion and observe it diminishes through increases in endocytosis. Consequently, glucose transporters internalize, and cytoplasmic glucose and ATP transiently decrease. This reduced energetic state activates AMPK, which inhibits YAP1, causing transcriptional-reprogramming and cell-cycle arrest. Impairing either endocytosis or AMPK activity prevents YAP1 inhibition and cell-cycle arrest after fusion. Together, these data demonstrate plasma membrane diminishment upon cell-fusion causes transient nutrient stress that may promote transcriptional-reprogramming independent from extrinsic cues.

The Role of Neutrophils and Their Extracellular Traps in the Synergy of Pre-eclampsia and HIV Infection

PURPOSE OF THE REVIEW

In our innate immune system, neutrophils are the first cells to sense signals of infection and to proceed to kill the invading pathogen. This is mediated by their production of neutrophil extracellular traps (NETS) to entrap pathogenic micro-organisms, preventing their amplification and dissemination. Pre-eclampsia (PE) is the leading cause of global maternal mortality, yet to date, there is no cure nor a gold-standard diagnostic strategy. The purpose of this review is to discover the role of neutrophils in PE as early identification markers. Additionally, this review aims to explore the role of neutrophils in HIV-infected pregnancies with PE as a source of synergy.

RECENT FINDINGS

Recent findings demonstrate an elevation of neutrophils and neutrophil extracellular traps (NETs) in PE placentae. This is due to their activation by excessive release of syncytiotrophoblast microparticles (STBM). There is also an elevation of NETs in HIV-infected placentae-where histone H3 entraps HIV by binding to its glycoprotein envelope. Additionally, histones H1 and H2A inhibit HIV infection. It is interesting to note that women with both PE and HIV infection have supressed NETs. This review focuses on the role of neutrophils in the synergy of PE and HIV infection. It is plausible that the deregulation of NETs in the synergy of pre-eclamptic HIV-infected women is strategic for the entrapment of the HIV-1 virus. Finally, it is plausible that neutrophils and NETS may act as early biomarkers of PE development. Graphical abstract.

Maternal Obesity Alters Placental Cell Cycle Regulators in the First Trimester of Human Pregnancy: New Insights for BRCA1

In the first trimester of pregnancy, placental development involves a wide range of cellular processes. These include trophoblast proliferation, fusion, and differentiation, which are dependent on tight cell cycle control. The intrauterine environment affects placental development, which also includes the trophoblast cell cycle. In this work, we focus on maternal obesity to assess whether an altered intrauterine milieu modulates expression and protein levels of placental cell cycle regulators in early human pregnancy. For this purpose, we use first trimester placental tissue from lean and obese women (gestational week 5+0-11+6, n = 58). Using a PCR panel, a cell cycle protein array, and STRING database analysis, we identify a network of cell cycle regulators increased by maternal obesity in which breast cancer 1 (BRCA1) is a central player. Immunostaining localizes BRCA1 predominantly to the villous and the extravillous cytotrophoblast. Obesity-driven BRCA1 upregulation is not able to be explained by DNA methylation (EPIC array) or by short-term treatment of chorionic villous explants at 2.5% oxygen with tumor necrosis factor α (TNF-α) (50 mg/mL), leptin (100 mg/mL), interleukin 6 (IL-6) (100 mg/mL), or high glucose (25 nM). Oxygen tension rises during the first trimester, but this change in vitro has no effect on BRCA1 (2.5% and 6.5% O2). We conclude that maternal obesity affects placental cell cycle regulation and speculate this may alter placental development.

Evaluation of placental chorionic villi histone 2A expression in HIV-infected women with pre-eclampsia

OBJECTIVE

Chorionic syncytiotrophoblasts (STB) function as an essential regulator of feto-maternal exchange. Therefore, STB actively differentiate to maintain their continuity for barrier function. However, the placental pathology reported in disorders such as pre-eclampsia (PE) threaten the homeostatic differentiation of STB. Since, HIV-1 requires the expression of co-receptors on STB to undergo vertical transmission, the aim of this study was to determine the effect of PE and HIV infection on the different stages of STB maturation [mature (H2A+) versus differentiating (H2A-)] and to immuno-localize and quantify the expression of histone 2A (H2A) i.e., positive (H2A+) and H2A negative (H2A-) nuclei within placental conducting and exchange villi. We also compared the expression of H2A + and H2A- nuclei between normotensive versus PE groups, HIV status and across the study population.

STUDY DESIGN

Placental tissue was obtained from pregnant normotensive (n = 30) and pre-eclamptic (n = 30) women after informed written consent. The study groups were further categorized by their HIV status. Immunohistochemistry using the anti-histone 2A (H2A) antibody to identify fully differentiated functional (mature) STB was performed using conventional techniques. Morphometric image analysis was utilized to quantify placental histone H2A immuno-expression in placental exchange and conducting villi. Statistical analysis was performed using GraphPad Prism software.

RESULTS

H2A + and H2A- nuclei were immuno-localized within STB of the exchange and conducting villi with H2A- nuclei prominent on the periphery. In the exchange villi, the immuno-expression of H2A + and H2A- nuclei were lower in the PE group compared to the normotensive group (p = 0.0003 and p < 0.0001 respectively). A reduced immuno-expression of H2A+ and H2A- nuclei was lower in exchange villi of HIV+ compared to HIV- placentae (p = 0.0002 and p = 0.0276 respectively).

CONCLUSIONS

PE and HIV reduces the percentage of H2A + and H2A- immuno-expression indicative of mature STB and actively differentiating STB respectively. We speculate that the different maturation states of STB and their orientation resultant of PE pathogenesis may be protective against the process of HIV-1 vertical transmission.

Molecular pathways of senescence regulate placental structure and function

The placenta is an autonomous organ that maintains fetal growth and development. Its multinucleated syncytiotrophoblast layer, providing fetal nourishment during gestation, exhibits characteristics of cellular senescence. We show that in human placentas from pregnancies with intrauterine growth restriction, these characteristics are decreased. To elucidate the functions of pathways regulating senescence in syncytiotrophoblast, we used dynamic contrast‐enhanced MRI in mice with attenuated senescence programs. This approach revealed an altered dynamics in placentas of p53^−/−, Cdkn2a^−/−, and Cdkn2a^−/−;p53^−/− mice, accompanied by histopathological changes in placental labyrinths. Human primary syncytiotrophoblast upregulated senescence markers and molecular pathways associated with cell‐cycle inhibition and senescence‐associated secretory phenotype. The pathways and components of the secretory phenotype were compromised in mouse placentas with attenuated senescence and in human placentas from pregnancies with intrauterine growth restriction. We propose that molecular mediators of senescence regulate placental structure and function, through both cell‐autonomous and non‐autonomous mechanisms.

Essential role of autophagy in resource allocation during sexual reproduction

Sexual reproduction is the most common form of reproduction among eukaryotes, which is characterized by a series of massive cellular or tissue renovations. Recent studies have revealed novel functions of autophagy during sexual reproductive processes, ranging from yeast to mammals. In mammals, autophagy is indispensable for spermatogenesis and oogenesis, and it participates in early embryonic development and maternal-fetus crosstalk to ensure the development of embryos or fetuses. Thus, autophagy provides the molecular basis for resource allocation among parents and their offspring, providing an important way to benefit the next generation.Abbreviations: ATG: autophagy-related; Becn1: beclin 1, autophagy related; CMA: chaperone-mediated autophagy; epg: ectopic PGL granules; ES: ectoplasmic specialization; EVTs: extravillous trophoblasts; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; PCD: programmed cell death; PTB: preterm birth; STB: syncytiotrophoblast.

The Density of Cell Nuclei at the Materno-Fetal Exchange Barrier is Sexually Dimorphic in Normal Placentas, but not in IUGR

Placental sexual dimorphism is of special interest in prenatal programming. Various postnatal diseases with gender dependent incidence, especially neuropsychiatric disorders like schizophrenia and autism spectrum disorders, have prenatal risk factors established. However, the functional relevance of placental microarchitecture in prenatal programming is poorly investigated, mainly due to a lack of statistically efficient methods. We hypothesized that the recently established 3D microscopic analysis of villous trees would be able to identify microscopic structural correlates of human placental sexual dimorphism. We analyzed the density of cell nuclei of villous trophoblast, i.e. the materno-fetal exchange barrier, in placentas from term pregnancies. The cell nuclei were grouped into proliferative and non-proliferative nuclei by detection of a proliferation marker (PCNA). Normal female placentas showed a higher density of non-proliferating nuclei (PCNA-negative) in villous trophoblast than normal male placentas. The density of PCNA-negative cell nuclei was higher in placentas of pregnancies with intrauterine growth retardation (IUGR) than in control placentas. The data of the present study shows that the density of non-proliferative cell nuclei in the syncytial layer of villous trophoblast is influenced by fetal sex and by IUGR, while proliferation remains unchanged. A novel concept of post-fusion regulation of syncytial structure and function is proposed.

Telomere Homeostasis and Senescence Markers Are Differently Expressed in Placentas From Pregnancies With Early- Versus Late-Onset Preeclampsia

BACKGROUND

Early-onset preeclampsia (EOPE; <34 weeks' gestation) usually has more severe morbidity for the mother and fetus compared to late-onset preeclampsia (LOPE). Telomere homeostasis is disrupted in preeclampsia (PE) and senescence markers are increased. The pathophysiologic differences between early and LOPE are not fully unraveled yet.

METHODS

We studied placental biopsies from 7 pregnancies with EOPE, 6 pregnancies with LOPE, and 13 healthy gestational age-matched controls. Telomere length and aggregate formation were assessed using qualitative fluorescence in situ hybridization and electronic quantitative methods. Senescence markers were evaluated including senescence-associated heterochromatin foci, β-galactosidase (SAβ-Gal), and P16 staining, as was the expression of P16 complementary DNA (cDNA) using real-time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

There were no differences in maternal age, gravidity, parity, body mass index, and mode of conception between the study and the control groups. The percentage of trophoblasts with short telomeres was higher in placental samples from EOPE (52.61% [12.27%]) versus LOPE (28.72% [10.14%]); both were higher compared to controls (7.53% [5.14%], P = .03). Aggregate formation was enhanced in EOPE (8.72% [2.49%]) compared to LOPE (4.54% [1.45%]); both were higher than in healthy controls (2.72% [1.08%], P = .03). Trophoblasts from EOPE versus LOPE were more likely to stain positive for SAβ-Gal and P16 compared to controls (P < .001). P16 cDNA expression assayed by RT-qPCR was 7.51 times higher in EOPE compared to controls and 5.86 times higher than in LOPE.

CONCLUSIONS

Impaired telomere homeostasis and senescence markers are more prominent in EOPE versus LOPE. These findings may contribute to our understanding of the pathophysiology and explain their different clinical presentations and outcomes.

Is there a role for placental senescence in the genesis of obstetric complications and fetal growth restriction?

The placenta ages as pregnancy advances, yet its continued function is required for a successful pregnancy outcome. Placental aging is a physiological phenomenon; however, there are some placentas that show signs of aging earlier than others. Premature placental senescence and aging are implicated in a number of adverse pregnancy outcomes, including fetal growth restriction, preeclampsia, spontaneous preterm birth, and intrauterine fetal death. Here we discuss cellular senescence, a state of terminal proliferation arrest, and how senescence is regulated. We also explore the role of physiological placental senescence and how aberrant placental senescence alters placental function, contributing to the pathophysiology of fetal growth restriction, preeclampsia, spontaneous preterm labor/birth, and unexplained fetal death.

Placental Dysfunction Underlies Increased Risk of Fetal Growth Restriction and Stillbirth in Advanced Maternal Age Women

Pregnancies in women of advanced maternal age (AMA) are susceptible to fetal growth restriction (FGR) and stillbirth. We hypothesised that maternal ageing is associated with utero-placental dysfunction, predisposing to adverse fetal outcomes. Women of AMA (≥35 years) and young controls (20-30 years) with uncomplicated pregnancies were studied. Placentas from AMA women exhibited increased syncytial nuclear aggregates and decreased proliferation, and had increased amino acid transporter activity. Chorionic plate and myometrial artery relaxation was increased compared to controls. AMA was associated with lower maternal serum PAPP-A and sFlt and a higher PlGF:sFlt ratio. AMA mice (38-41 weeks) at E17.5 had fewer pups, more late fetal deaths, reduced fetal weight, increased placental weight and reduced fetal:placental weight ratio compared to 8-12 week controls. Maternofetal clearance of 14C-MeAIB and 3H-taurine was reduced and uterine arteries showed increased relaxation. These studies identify reduced placental efficiency and altered placental function with AMA in women, with evidence of placental adaptations in normal pregnancies. The AMA mouse model complements the human studies, demonstrating high rates of adverse fetal outcomes and commonalities in placental phenotype. These findings highlight placental dysfunction as a potential mechanism for susceptibility to FGR and stillbirth with AMA.

Placental Origins of Chronic Disease

Epidemiological evidence links an individual's susceptibility to chronic disease in adult life to events during their intrauterine phase of development. Biologically this should not be unexpected, for organ systems are at their most plastic when progenitor cells are proliferating and differentiating. Influences operating at this time can permanently affect their structure and functional capacity, and the activity of enzyme systems and endocrine axes. It is now appreciated that such effects lay the foundations for a diverse array of diseases that become manifest many years later, often in response to secondary environmental stressors. Fetal development is underpinned by the placenta, the organ that forms the interface between the fetus and its mother. All nutrients and oxygen reaching the fetus must pass through this organ. The placenta also has major endocrine functions, orchestrating maternal adaptations to pregnancy and mobilizing resources for fetal use. In addition, it acts as a selective barrier, creating a protective milieu by minimizing exposure of the fetus to maternal hormones, such as glucocorticoids, xenobiotics, pathogens, and parasites. The placenta shows a remarkable capacity to adapt to adverse environmental cues and lessen their impact on the fetus. However, if placental function is impaired, or its capacity to adapt is exceeded, then fetal development may be compromised. Here, we explore the complex relationships between the placental phenotype and developmental programming of chronic disease in the offspring. Ensuring optimal placentation offers a new approach to the prevention of disorders such as cardiovascular disease, diabetes, and obesity, which are reaching epidemic proportions.

Altered expression of G1/S phase cell cycle regulators in placental mesenchymal stromal cells derived from preeclamptic pregnancies with fetal-placental compromise

Herein, we evaluated whether Placental Mesenchymal Stromal Cells (PDMSCs) derived from normal and Preeclamptic (PE) placentae presented differences in the expression of G1/S-phase regulators p16^INK4A, p18^INK4C, CDK4 and CDK6. Finally, we investigated normal and PE-PDMSCs paracrine effects on JunB, Cyclin D1, p16^INK4A, p18^INK4C, CDK4 and CDK6 expressions in physiological term villous explants.

PDMSCs were isolated from physiological (n = 20) and PE (n = 24) placentae. Passage three normal and PE-PDMSC and conditioned media (CM) were collected after 48h. Physiological villous explants (n = 60) were treated for 72h with normal or PE-PDMSCs CM. Explants viability was assessed by Lactate Dehydrogenase Cytotoxicity assay. Cyclin D1 localization was evaluated by Immuofluorescence (IF) while JunB, Cyclin-D1 p16^INK4A, p18^INK4C, CDK4 and CDK6 levels were assessed by Real Time PCR and Western Blot assay.

We reported significantly increased p16^INK4A and p18^INK4C expression in PE- relative to normal PDMSCs while no differences in CDK4 and CDK6 levels were detected. Explants viability was not affected by normal or PE-PDMSCs CM. Normal PDMSCs CM increased JunB, p16^INK4 and p18^INK4C and decreased Cyclin-D1 in placental tissues. In contrast, PE-PDMSCs CM induced JunB downregulation and Cyclin D1 increase in placental explants. Cyclin D1 IF staining showed that CM treatment targeted mainly the syncytiotrophoblast.

We showed Cyclin D1-p16INK4A/p18INK4C altered pathway in PE-PDMSCs demonstrating an aberrant G1/S phase transition in these pathological cells. The abnormal Cyclin D1-p16INK4A/p18INK4C expression in explants conditioned by PE-PDMSCs media suggest a key contribution of mesenchymal cells to the altered trophoblast cell cycle regulation typical of PE pregnancies with fetal-placental compromise.

Systemic and placental α-klotho: Effects of preeclampsia in the last trimester of gestation

INTRODUCTION

α-klotho is an anti-aging protein, potentially important in preeclampsia (PE). Produced by kidney, brain and placenta, and by mRNA splicing is both a full-length membrane-bound and a truncated soluble protein in the circulation. The membrane-bound protein is an obligate co-receptor for fibroblast growth factor 23 (FGF23) and its action on receptor (FGFR), but ADAM proteinases also cause its shedding. The aims of this study were to investigate levels of maternal plasma, placental, and fetal membrane α-Klotho and their association with placental accelerated villous maturation (AVM) in PE. In addition, placental and membrane levels of ADAM17 and FGFR were measured in the same patients.

METHODS

Maternal blood, placenta and fetal membranes from 61 women (31 with PE and 30 controls) between 32 and 40 weeks gestation were collected. Plasma α-klotho was measured by ELISA, and quantitative immunohistochemistry used for α-klotho, ADAM17 and FGFR1 in tissues. Placental AVM was histologically assessed.

RESULTS

Maternal plasma levels of α-Klotho were higher in PE compared to controls (p = 0.01) and patients with the highest levels had significantly less AVM (p = 0.03). α-Klotho, ADAM17, and FGFR were all present in syncytiotrophoblast and cytotrophoblast of membranes. Between 32 and 40 weeks gestation, all placental levels decreased in controls respectively (p = 0.04, p = 0.004, p = 0.05), but not in PE. Fetal membrane levels were unchanged.

DISCUSSION

Maternal plasma α-Klotho was increased in PE and its levels associated with reduced placental AVM. Changes in placental α-Klotho, ADAM17, and FGFR suggest their involvement in the pathophysiology of PE.

Mitochondrial - Endoplasmic reticulum interactions in the trophoblast: Stress and senescence

Placental stress has been implicated in the pathophysiology of complications of pregnancy, including growth restriction and pre-eclampsia. Initially, attention focused on oxidative stress, but recently mitochondrial and endoplasmic reticulum stress have been identified. Complex molecular interactions exist among these different forms of stress, making it unlikely that any occurs in isolation. In part, this is due to close physiological connections between the two organelles principally involved, mitochondria and the endoplasmic reticulum (ER), mediated through Ca²⁺ signalling. Here, we review the involvement of the mitochondria-ER unit in the generation of stress within the trophoblast, and consider consequences for obstetric outcome. Mild stress may induce adaptive responses, including upregulation of antioxidant defences and autophagy, while moderate levels may affect stem cell behaviour and reduce cell proliferation, contributing to the growth-restricted phenotype. High levels of stress can stimulate release of pro-inflammatory cytokines and anti-angiogenic factors, increasing the risk of pre-eclampsia. In addition, chronic stress may promote senescence of the trophoblast, which in other cell types leads to a pro-inflammatory senescence-associated secretory phenotype. Evidence from rodents suggests that a degree of trophoblastic stress develops with increasing gestational age in normal pregnancies. The increase in maternal concentrations of soluble fms-like tyrosine kinase-1 (sFlt-1) and reduction in placental growth factor (PlGF) suggest the same may occur in the human, starting around 30 weeks of pregnancy. Placental malperfusion, or co-existing maternal conditions, such as diabetes, will exacerbate that stress. Amelioration of trophoblastic stress should remain a research priority, but will be difficult due to the complexity of the molecular pathways involved.

Telomere homeostasis in trophoblasts and in cord blood cells from pregnancies complicated with preeclampsia

BACKGROUND

Telomeres are nucleoprotein structures, essential for chromosome stability and cell survival. Telomeres are progressively shortened with each cell division and by environmental factors. Telomere loss has been linked to age and stress-induced premature senescence. Dysfunctional telomeres tend to form aggregates, which consist of the end-to-end fusion of telomeres. Telomere elongation is carried out by telomerase, which is a specific reverse transcriptase capable of adding telomeric repeats to chromosome termini. The TERC gene encodes the RNA template of the telomerase. Another compensatory mechanism that is enhanced in response to telomere shortening and senescence is the telomere capture (TC). Telomere shortening and elevated aggregate formation have been observed in trophoblasts from pregnancies complicated with preeclampsia (PE).

OBJECTIVE

We opted to study mechanisms of telomere shortening in trophoblasts from pregnancies complicated with PE and to assess telomere length and homeostasis in fetal cord blood cells from PE pregnancies.

STUDY DESIGN

Placental specimens and cord blood samples from uncomplicated pregnancies and from pregnancies complicated with PE were collected. Staining with 4',6-diamidino-2-phenylindole was used to assess nuclear fragmentation: senescence-associated heterochromatin foci (SAHF). Fluorescence in situ hybridization was used to evaluate TERC gene copy number and TC. Telomere length and aggregate formation were assessed in cord blood using quantitative fluorescence in situ hybridization. Nonparametric Kruskal-Wallis and Mann-Whitney U tests were applied to test the differences between the study groups.

RESULTS

Nine samples from pregnant patients with PE without intrauterine growth restriction and 14 samples from uncomplicated pregnancies that served as controls were collected. In cord blood cells, no differences were observed in telomere length, aggregate formation, TERC copy number, TC, or SAHF between PE and controls. In PE trophoblasts the percentage of cells with SAHF was higher in PE trophoblasts compared to controls (56.8 SD = 10.5% vs 35.2 SD = 10.7%, P = .028). The percentage of cells with abnormal TERC copy number was increased in PE trophoblasts compared to controls (31 ± 3.6% vs 12.97 SD = 5%, P = .004) as well as the percentage of cells with TC (27.4 SD = 9.4% vs 16 SD = 4.67%, P = .028).

CONCLUSION

We suggest that telomere shortening in PE trophoblasts is linked to cellular increased senescence. Alterations in telomere homeostasis mechanisms are present in such cases. These findings support the role of telomeres in the pathogenesis of trophoblastic dysfunction in PE. The lack of telomere shortening, modified telomere homeostasis mechanisms, and increased senescence in cord blood from pregnancies complicated with PE suggests that these processes are probably restricted primarily to the placenta.

CCN1 (CYR61) and CCN3 (NOV) signaling drives human trophoblast cells into senescence and stimulates migration properties

During placental development, continuous invasion of trophoblasts into the maternal compartment depends on the support of proliferating extravillous trophoblasts (EVTs). Unlike tumor cells, EVTs escape from the cell cycle before invasion into the decidua and spiral arteries. This study focused on the regulation properties of glycosylated and non-glycosylated matricellular CCN1 and CCN3, primarily for proliferation control in the benign SGHPL-5 trophoblast cell line, which originates from the first-trimester placenta. Treating SGHPL-5 trophoblast cells with the glycosylated forms of recombinant CCN1 and CCN3 decreased cell proliferation by bringing about G0/G1 cell cycle arrest, which was accompanied by the upregulation of activated Notch-1 and its target gene p21. Interestingly, both CCN proteins increased senescence-associated β-galactosidase activity and the expression of the senescence marker p16. The migration capability of SGHPL-5 cells was mostly enhanced in response to CCN1 and CCN3, by the activation of FAK and Akt kinase but not by the activation of ERK1/2. In summary, both CCN proteins play a key role in regulating trophoblast cell differentiation by inducing senescence and enhancing migration properties. Reduced levels of CCN1 and CCN3, as found in early-onset preeclampsia, could contribute to a shift from invasive to proliferative EVTs and may explain their shallow invasion properties in this disease.

Placental hypoxia: the lesions of maternal malperfusion

The placental lesions classically ascribed to placental hypoxia, here denoted maternal malperfusion (MMP), are among the more significant that a placental pathologist may encounter. Yet the appearance of these lesions may be subtle, and the clinical implication of their diagnosis is frequently unclear. The aim of this review is to provide a more nuanced perspective on the clinical utility of placental pathology for the detection of MMP. The review will first detail MMP lesions in the placenta and discuss their associations with pregnancy complications. The review will then delve into the diagnostic and interpretive difficulties of these lesions. Finally, recent research findings that may aid in the development of better diagnostic tools will be briefly discussed.

HLA-G-mediated NK cell senescence promotes vascular remodeling: implications for reproduction

The uterus in early pregnancy is a non-lymphoid organ that is enriched in natural killer (NK) cells. Studies to address the role of these abundant human NK cells at the maternal/fetal interface have focused on their response to the major histocompatibility complex (MHC) molecules on fetal trophoblast cells that they contact. The interaction of maternal NK cell receptors belonging to the killer cell immunoglobulin-like receptor (KIR) family with trophoblast MHC class I molecules in pregnancy can regulate NK cell activation for secretion of pro-angiogenic factors that promote placental development. This review will cover the role of KIR at the maternal/fetal interface and focus on KIR2DL4, a KIR family member that is uniquely poised to play a role in pregnancy due to the restricted expression of its ligand, human leukocyte antigen (HLA)-G, by fetal trophoblast cells early in pregnancy. The pathways by which KIR2DL4-HLA-G interactions induce the cellular senescence of NK cells and the role of the resulting senescence-associated secretory phenotype (SASP) in vascular remodeling will be discussed in the context of reproduction.