The role of cellular senescence in ageing of the placenta

Hyperglycemia-induced α-Klotho downregulation impairs mitophagy and promotes placental dysfunction in T2DM pregnancies

INTRODUCTION

Placental dysfunction in pregnancies complicated by type 2 diabetes mellitus (T2DM) is associated with adverse maternal and fetal outcomes. α-Klotho, a multifunctional anti-aging protein, plays a critical role in maintaining cellular homeostasis, but its role in T2DM-induced placental dysfunction remains poorly understood.

METHODS

Placental tissues from T2DM pregnancies and normoglycemic controls were analyzed for α-Klotho expression using qRT-PCR, Western blot, and immunohistochemistry. BeWo trophoblast cells were cultured under normoglycemic and hyperglycemic conditions, with α-Klotho knockdown and overexpression to explore its regulatory effects. Transcriptomic analysis was conducted to identify affected pathways, and markers of mitophagy and reactive oxygen species (ROS) were analyzed.

RESULTS

α-Klotho expression was significantly reduced in the placentas of T2DM pregnancies and in trophoblast cells under hyperglycemic conditions. Transcriptomic analysis identified pathways related to mitochondrial dysfunction and impaired mitophagy as key processes regulated by α-Klotho. Hyperglycemia and α-Klotho knockdown suppressed mitophagy, while ROS production was increased, further exacerbating oxidative stress. Overexpression of α-Klotho restored mitophagy and mitigated ROS activation.

DISCUSSION

This study reveals that α-Klotho downregulation contributes to T2DM-induced placental dysfunction by impairing mitophagy and increasing oxidative stress. These findings provide new insights into the molecular mechanisms underlying placental abnormalities in diabetic pregnancies and highlight α-Klotho as a potential therapeutic target.

Cystatin 6 (CST6) and Legumain (LGMN) are potential mediators in the pathogenesis of preeclampsia

Preeclampsia results from placental insufficiency and causes maternal endothelial dysfunction and multi-organ damage. Our in-silico analysis identified Cystatin 6 (CST6), a cysteine protease inhibitor, as located on the placental surface where it might be released into maternal circulation. This study aimed to characterise CST6 and one of its high affinity targets, Legumain (LGMN), in preeclampsia and assess its biomarker potential by measuring levels in maternal circulation. Placental CST6 mRNA expression was significantly increased in 78 pregnancies complicated by early-onset preeclampsia (delivering at < 34 weeks' gestation) relative to 30 gestation matched controls (P < 0.0001). LGMN mRNA expression was significantly decreased (P = 0.0309). Circulating CST6 was increased in 35 pregnancies complicated by early-onset preeclampsia (< 34 weeks' gestation) relative to 27 gestation matched controls (P = 0.0261), and LGMN levels remained unchanged. At 36 weeks' gestation, circulating CST6 was significantly increased (P = 0.001), while LGMN was significantly decreased (P = 0.0135) in 21 pregnancies preceding diagnosis of preeclampsia at term, compared to 184 pregnancies that did not develop preeclampsia. Human trophoblast stem cells (hTSC) were differentiated into syncytiotrophoblast or extravillous trophoblast (EVT) to evaluate CST6 and LGMN expression in these trophoblast lineages. CST6 and LGMN mRNA expression were significantly increased across 96 h after syncytiotrophoblast (P = 0.0066 and P = 0.0010 respectively) and EVT differentiation (P = 0.0618 and P = 0.0016 respectively), with the highest expression in syncytiotrophoblast. Computational analysis of two publicly available single-cell and single-nuclei RNA sequencing datasets correlated with the expression pattern observed in vitro. When syncytiotrophoblast cells were exposed to hypoxia (1% O2 vs. 8% O2), CST6 expression significantly increased (P = 0.0079), whilst LGMN expression was unchanged. The vascular endothelium may serve as an additional source of circulating CST6 and LGMN in preeclampsia.  Induction of dysfunction in endothelial cells by TNFα, caused reduced CST6 expression (P = 0.0036), whilst LGMN expression remained unchanged. Administering recombinant CST6 to endothelial cells enhanced markers of endothelial dysfunction and LGMN expression in the presence of TNFα. These findings indicate an inverse relationship between CST6 and LGMN in the placenta and maternal circulation in preeclampsia. We suggest elevated circulating levels of CST6 may be induced by placental hypoxia. This study provides novel insight into the dysregulation of CST6 and LGMN in preeclampsia and introduces their potential roles in human pregnancy and associated pathology.

Single-nucleus transcriptional profiling of the placenta reveals the syncytiotrophoblast stress response to COVID-19

BACKGROUND

COVID-19 in pregnancy is associated with placental immune activation, inflammation, and vascular malperfusion, but its impact on syncytiotrophoblast biology and function is unclear.

OBJECTIVE

This study aimed to determine the effects of maternal COVID-19 on placental syncytiotrophoblasts using single-nucleus transcriptional profiling and to compare placental stress responses in COVID-19 and preeclampsia.

STUDY DESIGN

For transcriptional characterization of syncytiotrophoblasts, we used the single-nucleus RNA sequencing platform, single-cell combinatorial indexing RNA sequencing (sci-RNA-seq3), to profile placental villi and fetal membranes from unvaccinated patients with symptomatic COVID-19 at birth (n = 4), gestational age-matched controls (n = 4), and a case of critical COVID-19 in the second trimester with delivery at term (n = 1). Clustering of nuclei and differential gene expression analysis was performed in Seurat. Gene ontology analysis was conducted using Enrichr. High-confidence transcriptional target analysis was used to identify key transcription factor nodes governing the syncytiotrophoblast response to maternal SARS-CoV-2 infection. Bioinformatic approaches were further used to compare the COVID-19 dataset to published preeclampsia gene signatures. Tissue analysis, including immunofluorescence, was conducted to validate the transcriptional data and to compare COVID-19 and preeclampsia placental histology for an expanded cohort of placentas: controls (n = 6), asymptomatic COVID-19 (n = 3), symptomatic COVID-19 (n = 5), and preeclampsia with severe features (n = 7).

RESULTS

The analyzed dataset comprised 15 cell clusters and 47,889 nuclei. We identified 3 clusters of syncytiotrophoblasts representing fusing and mature nuclei with overlapping but distinct transcriptional responses to COVID-19. Bioinformatic analyses indicated that COVID-19 is associated with the following alterations in syncytiotrophoblasts: (1) endoplasmic reticulum stress and activation of stress signaling pathways, including the unfolded protein response and integrated stress response; (2) regulation of gene expression by CCAAT/enhancer-binding protein beta (CEBPB), a master transcription factor of the syncytiotrophoblast lineage; and (3) upregulation of preeclampsia-associated genes. Using complementary methods, we confirmed increased levels of stress response proteins (eg, BiP, G3BP1) in syncytiotrophoblasts, unfolded protein response signaling (spliced XBP1 mRNA), and CEBPB activation (phosphorylation) in COVID-19. Increased cytotrophoblast proliferation (Ki-67) was also detected in COVID-19, consistent with a trophoblast response to injury. Markers of stress detected in preeclampsia demonstrated similarities in the placental stress phenotype of COVID-19 and preeclampsia.

CONCLUSION

Maternal COVID-19 is associated with syncytiotrophoblast endoplasmic reticulum stress and activation of the syncytiotrophoblast lineage transcription factor, CEBPB. Similarities between syncytiotrophoblast stress in COVID-19 and preeclampsia provide insights into their clinical association.

Cells of all trades - on the importance of spatial positioning of senescent cells in development, healing and aging

Biological processes are often spatially regulated, ensuring molecular and cellular events occur in their most strategically advantageous locations. Cellular senescence, marked by cell cycle arrest and hypersecretion, is recognized as an important part of physiological processes like development and healing, but it also contributes to aging and disease. However, the spatial distribution of senescent cells and its physiological and pathological impact remain unclear. Here we compile evidence on senescent cell localization in development, healing, and aging. We emphasize the significance of their spatial patterns and speculate on the effects of disrupted spatial positioning of senescence in relation to pathologies. To summarize the specific spatial functions of senescent cells, we propose to refer to them as 'barrier' and 'conductor' functions. The 'barrier' function of senescent cells, due to their altered morphology and apoptosis resistance, separates tissues and builds a border between two environments. The conductor function, with the secretion of signaling factors, influences the surrounding area and stimulates migration, differentiation, or proliferation, among other processes. Overall, this Review explores the spatial patterning of cellular senescence in biological processes, highlighting its dual roles as 'barrier' and 'conductor' functions, and examines the implications of senescent cell distribution in development, healing, aging, and disease.

Trophoblast Fusion in Hypertensive Disorders of Pregnancy and Preeclampsia

Trophoblast fusion into the multinucleated syncytiotrophoblast (SCT) appears as an inescapable feature of placentation in mammals and other viviparous species. The trophoblast cells underlying the syncytium are considered a reservoir for the restoration of the aging peripheric structure. The transition from trophoblasts to SCTs has to be tightly regulated, and could be altered by genetic anomalies or environmental exposure. The resulting defective placental function could be one of the causes of the major placental diseases, such as preeclampsia (PE) and Intra-Uterine Growth Restriction (IUGR). This review attempts to take stock of the current knowledge about fusion mechanisms and their deregulations.

Characterization of senescence-associated transcripts in the human placenta

INTRODUCTION

Fusion of mononucleated cytotrophoblasts into syncytium leads to trophoblast senescence. Yet, premature senescence is associated with preeclampsia, fetal growth restriction (FGR), and related obstetrical syndromes. A set of 28 transcripts that comprise senescence-associated secretory phenotype (SASP) was recently described in placentas from women with preeclampsia. We posited that this transcript set is uniquely regulated in late-term placentas or in placentas derived from participants with major obstetrical syndromes.

METHODS

Using our large placental RNAseq bank, we analyzed data from healthy participants (n = 33) with histologically normal placentas, representing delivery at 37-41 weeks. To represent diseases, we included RNAseq data from participants (n = 220) with severe preeclampsia, FGR, FGR with a hypertensive disorder (FGR + HDP), or spontaneous preterm delivery, and healthy controls (n = 129). We also assessed the expression of several SASPs in primary human trophoblasts that were exposed in vitro to hypoxia, reduced differentiation, or ferroptotic or apoptotic signals.

RESULTS

Among the 28 SASP transcripts analyzed, eight had a significant change between deliveries at <37 weeks vs ≥ 41 weeks, including upregulation of FSTL3, IL1RL1, INHBA, and VEGFA and downregulation of STC1, RARRES2, MRC2, and SELP. The expression of SASP mRNAs was enriched in the placentas from the assessed syndromes, with most expression changes in placentas from FGR/HDP. Our in vitro analysis associated hypoxia or apoptosis with altered expression of FSTL3, VEGFA, and DKK1.

DISCUSSION

A set of placental SASPs defines late-term placentas, placental dysfunction-related clinical syndromes, and in vitro-defined trophoblast injury. Trophoblastic SASP signatures may assist in characterizing placental senescence in health and disease.

Gestational exposure to nanoplastics disrupts fetal development by promoting the placental aging via ferroptosis of syncytiotrophoblast

Micro(nano)plastics (MNPs), are emerging environmental pollutants that have garnered widespread attention. Epidemiological and animal studies have shown that MNPs exposure during pregnancy is associated with adverse pregnancy outcomes, such as intrauterine growth restriction (IUGR) and miscarriage. However, the underlying mechanisms remain poorly understood. In this study, we found that exposure to a high dose (1 μg·mL-1) of 100 nm polystyrene nanoparticles (NPs) from gestational day (GD) 0 to GD17 significantly decreased fetal weight and increased the number of resorptions compared to the control group. Moreover, fetal weight was significantly lower in the high-dose group than in the low-dose (0.1 μg·mL-1) group. Meanwhile, ferroptosis and senescence were observed in placentas from mice exposed to high dose of NPs. In vitro experiments using human syncytiotrophoblast (STB) cells differentiated from BeWo cells, we found that NPs caused ferroptosis and senescence in STB cells. Subsequent investigations revealed that the inhibition of the ferroptosis signaling by ferrostain-1 (Fer-1) or deferiprone (DFP) ameliorated senescence induced by NPs in human STB cells. Furthermore, alleviating placental senescence using Fer-1 significantly improves fetal weight loss caused by NPs exposure during pregnancy in mice. Taken together, our results demonstrated that NPs exposure during pregnancy activated the ferroptosis pathway in placental STB, resulting in senescence of STB, which may attribute to the NPs-induced IUGR. This study not only elucidated the mechanistic link between NPs exposure and adverse pregnancy outcomes but also highlighted the necessity for targeted interventions to protect fetal health, underscoring the broader implications for environmental and public health policy.

Preeclampsia as a Study Model for Aging: The Klotho Gene Paradigm

Aging and pregnancy are often considered opposites in a woman's biological timeline. Aging is defined by a gradual decline in the functional capabilities of an organism over its lifetime, while pregnancy is characterized by the presence of the transient placenta, which fosters the cellular fitness necessary to support fetal growth. However, in the context of preeclampsia, pregnancy and aging share common hallmarks, including clinical complications, altered cellular phenotypes, and heightened oxidative stress. Furthermore, women with pregnancies complicated by preeclampsia tend to experience age-related disorders earlier than those with healthy pregnancies. Klotho, a gene discovered fortuitously in 1997 by researchers studying aging mechanisms, is primarily expressed in the kidneys but also to a lesser extent in several other tissues, including the placenta. The Klotho protein is a membrane-bound protein that, upon cleavage by ADAM10/17, is released into the circulation as soluble Klotho (sKlotho) where it plays a role in modulating oxidative stress. This review focuses on the involvement of sKlotho in the development of preeclampsia and age-related disorders, as well as the expression of the recently discovered Mytho gene, which has been associated with skeletal muscle atrophy.

Placental trophoblast aging in advanced maternal age is related to increased oxidative damage and decreased YAP

Introduction

The advanced maternal age (AMA) pregnancies escalate rapidly, which are frequently linked to higher risks of adverse outcomes. Advanced maternal age (AMA) placenta exhibited premature aging, presumably resulting in trophoblast dysfunction, inadequate placentation. However, the precise reasons and mechanisms of trophoblast aging in AMA placenta remain unclear, posing a significant limitation to provide effective guidance for prenatal healthcare in clinical settings. Notably, the organism shows heightened vulnerability to oxidative damage as it ages. YAP (Yes-associated protein) was reported to play a critical role in regulation of aging and resisting oxidative damage, yet these roles had not been elucidated in the placenta. Therefore, this study explored the relationship between trophoblast cell aging and oxidative injury and YAP in AMA pregnancy, which not only provided an insight into the mechanisms of trophoblast cell aging, but also provide valuable directions for healthcare during AMA pregnancy.

Methods

In this study, human term placentas were collected from AMA and normal pregnancies for the analysis of aging, oxidative damage and YAP level. HTR8/SVneo cells were manipulated with (hydrogen peroxide) H2O2 to explore the effects of oxidative damage on trophoblast cell senescence and YAP levels. YAP expression in HTR8/SVneo cells was manipulated to investigate its role in trophoblastic senescence and oxidative damage.

Results

Compared with the control group, the AMA placenta exhibits increased aging biomarkers, which is coupled with an elevation in oxidative damage within placental trophoblast cells and a notable decline in YAP levels. Cellular experiments demonstrated that oxidative damage from H2O2 triggered trophoblast cell senescence and resulted in a reduction of YAP levels. Furthermore, employing molecular modification to silence YAP expression in these cells led to an induction of aging. Conversely, overexpressing YAP ameliorated both trophoblast cell aging and the associated DNA oxidative damage that arised from H2O2.

Conclusion

The decline of YAP in AMA pregnancy should be responsible for the increased oxidative injury and premature placenta aging, indicating that YAP plays a significant role in combating oxidative damage and delaying aging, thereby providing a new guidance for prenatal care in AMA pregnancies. Maintaining YAP levels or implementing anti-oxidative stress interventions could potentially mitigate the incidence of complications involved AMA pregnancy.

Placentas From SARS-CoV-2 Infection During Pregnancy Exhibit Foci of Oxidative Stress and DNA Damage

PROBLEM

COVID-19 during pregnancy is linked to increased maternal morbidity and a higher incidence of preterm births (PTBs), yet the underlying mechanisms remain unclear. Cellular senescence, characterized by the irreversible cessation of cell division, is a critical process in placental function, and its dysregulation has been implicated in pregnancy complications like PTB. Senescence can be induced by various stressors, including oxidative stress, DNA damage, and viral infections.

METHOD OF STUDY

In this study, we determined whether COVID-19 had an impact on placental senescence. We examined placentas from women infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (n = 10 term, 4 preterm) compared to uninfected controls (n = 10 term, 3 preterm). The placentas were analyzed for SARS-CoV-2 infection (spike and nucleocapsid viral proteins), markers of DNA damage (γH2AX) and oxidative stress (ROS), and senescence (telomere length, cell cycle regulators, and senescence-associated secretory phenotype [SASP]).

RESULTS

Although no overall differences in cellular senescence markers were observed between the COVID-19 positive and negative groups, we found increased secreted SASP markers. Confocal microscopy of placentas from COVID-19 positive cases revealed localized areas of oxidative stress and DNA damage colocalized with SARS-CoV-2 spike protein.

CONCLUSIONS

These findings indicate that SARS-CoV-2 infection induces localized focal placental damage, warranting further investigation into its impact on maternal and perinatal outcomes.

Alterations in the placental proteome in association with the presence of black carbon particles: A discovery study

BACKGROUND

Exposure to ambient air pollution is known to cause direct and indirect molecular expression changes in the placenta, on the DNA, mRNA, and protein levels. Ambient black carbon (BC) particles can be found in the human placenta already very early in gestation. However, the effect of in utero BC exposure on the entire placental proteome has never been studied to date.

OBJECTIVES

We explored whether placental proteome differs between mothers exposed to either high or low BC levels throughout the entire pregnancy.

METHODS

We used placental tissue samples from the ENVIRONAGE birth cohort, of 20 non-smoking, maternal- and neonate characteristic-matched women exposed to high (n = 10) or low (n = 10) levels of ambient BC throughout pregnancy. We modeled prenatal BC exposure levels based on the mother's home address and measured BC levels in the fetal side of the placenta. The placental proteome was analyzed by nano-liquid chromatography Q-TOF mass spectrometry. PEAKS software was used for protein identification and label-free quantification. Protein-protein interaction and functional pathway enrichment analyses were performed with the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) software.

RESULTS

The accumulation of BC particles in placenta was 2.19 times higher in the high versus low exposure group (20943.4 vs 9542.7 particles/mm³; p = 0.007). Thirteen proteins showed a ≥2-fold expression difference between the two exposure groups, all overexpressed in the placentas of women prenatally exposed to high BC levels. Three protein-protein interactions were enriched within this group, namely between TIMP3 and COL4A2, SERPINE2 and COL4A2, and SERPINE2 and GP1BB. Functional pathway enrichment analysis put forward pathways involved in extracellular matrix-receptor interaction, fibrin clot formation, and sodium ion transport regulation.

DISCUSSION

Prenatal BC exposure affects the placental proteome. Future research should focus on the potential consequences of these alterations on placental functioning, and health and disease during early childhood development.

Roles of chromatin and genome instability in cellular senescence and their relevance to ageing and related diseases

Ageing is a complex biological process in which a gradual decline in physiological fitness increases susceptibility to diseases such as neurodegenerative disorders and cancer. Cellular senescence, a state of irreversible cell-growth arrest accompanied by functional deterioration, has emerged as a pivotal driver of ageing. In this Review, we discuss how heterochromatin loss, telomere attrition and DNA damage contribute to cellular senescence, ageing and age-related diseases by eliciting genome instability, innate immunity and inflammation. We also discuss how emerging therapeutic strategies could restore heterochromatin stability, maintain telomere integrity and boost the DNA repair capacity, and thus counteract cellular senescence and ageing-associated pathologies. Finally, we outline current research challenges and future directions aimed at better comprehending and delaying ageing.

SenNet recommendations for detecting senescent cells in different tissues

Once considered a tissue culture-specific phenomenon, cellular senescence has now been linked to various biological processes with both beneficial and detrimental roles in humans, rodents and other species. Much of our understanding of senescent cell biology still originates from tissue culture studies, where each cell in the culture is driven to an irreversible cell cycle arrest. By contrast, in tissues, these cells are relatively rare and difficult to characterize, and it is now established that fully differentiated, postmitotic cells can also acquire a senescence phenotype. The SenNet Biomarkers Working Group was formed to provide recommendations for the use of cellular senescence markers to identify and characterize senescent cells in tissues. Here, we provide recommendations for detecting senescent cells in different tissues based on a comprehensive analysis of existing literature reporting senescence markers in 14 tissues in mice and humans. We discuss some of the recent advances in detecting and characterizing cellular senescence, including molecular senescence signatures and morphological features, and the use of circulating markers. We aim for this work to be a valuable resource for both seasoned investigators in senescence-related studies and newcomers to the field.

Oxidative Stress and Placental Pathogenesis: A Contemporary Overview of Potential Biomarkers and Emerging Therapeutics

Oxidative stress (OS) plays a crucial role in placental pathogenesis and pregnancy-related complications. This review explores OS's impact on placental development and function, focusing on novel biomarkers for the early detection of at-risk pregnancies and emerging therapeutic strategies. We analyzed recent research on OS in placental pathophysiology, examining its sources, mechanisms, and effects. While trophoblast invasion under low-oxygen conditions and hypoxia-induced OS regulate physiological placental development, excessive OS can lead to complications like miscarriage, preeclampsia, and intrauterine growth restriction. Promising OS biomarkers, including malondialdehyde, 8-isoprostane, and the sFlt-1/PlGF ratio, show potential for the early detection of pregnancy complications. Therapeutic strategies targeting OS, such as mitochondria-targeted antioxidants, Nrf2 activators, and gasotransmitter therapies, demonstrate encouraging preclinical results. However, clinical translation remains challenging. Future research should focus on validating these biomarkers in large-scale studies and developing personalized therapies to modulate placental OS. Emerging approaches like extracellular vesicle-based therapies and nanomedicine warrant further investigation for both diagnostic and therapeutic applications in pregnancy-related complications. Integrating OS biomarkers with other molecular and cellular markers offers improved potential for the early identification of at-risk pregnancies.

The interaction of ER stress and autophagy in trophoblasts: navigating pregnancy outcome†

The endoplasmic reticulum is a complex and dynamic organelle that initiates unfolded protein response and endoplasmic reticulum stress in response to the accumulation of unfolded or misfolded proteins within its lumen. Autophagy is a paramount intracellular degradation system that facilitates the transportation of proteins, cytoplasmic components, and organelles to lysosomes for degradation and recycling. Preeclampsia and intrauterine growth retardation are two common complications of pregnancy associated with abnormal trophoblast differentiation and placental dysfunctions and have a major impact on fetal development and maternal health. The intricate interplay between endoplasmic reticulum stress, and autophagy and their impact on pregnancy outcomes, through mediating trophoblast differentiation and placental development, has been highlighted in various reports. Autophagy controls trophoblast regulation through a variety of gene expressions and signaling pathways while excessive endoplasmic reticulum stress triggers downstream apoptotic signaling, culminating in trophoblast apoptosis. This comprehensive review delves into the intricacies of placental development and explores the underlying mechanisms of preeclampsia and intrauterine growth retardation. In addition, this review will elucidate the molecular mechanisms of endoplasmic reticulum stress and autophagy, both individually and in their interplay, in mediating placental development and trophoblast differentiation, particularly highlighting their roles in preeclampsia and intrauterine growth retardation development. This research seeks to the interplay between endoplasmic reticulum stress and impaired autophagy in the placental trophoderm, offering novel insights into their contribution to pregnancy complications.

Sudden Intrauterine Unexplained Death (SIUD) and Oxidative Stress: Placental Immunohistochemical Markers

BACKGROUND

Intrauterine fetal death and perinatal death represent one of the most relevant medical scientific problems since, in many cases, even after extensive investigation, the causes remain unknown. The considerable increase in medical legal litigation in the obstetrical field that has witnessed in recent years, especially in cases of stillborn births, has simultaneously involved the figure of the forensic pathologist in scientific research aimed at clarifying the pathophysiological processes underlying stillbirth.

METHODS

our study aims to analyze cases of sudden intrauterine unexplained death syndrome (SIUD) to evaluate the role of oxidative stress in the complex pathogenetic process of stillbirth. In particular, the immunohistochemical expression of specific oxidative stress markers (NOX2, NT, iNOS, 8-HODG, IL-6) was evaluated in tissue samples of placentas of SIUDs belonging to the extensive case series (20 cases), collected from autopsy cases of the University of Ferrara and Politecnica delle Marche between 2017 and 2023.

RESULTS

The study demonstrated the involvement of oxidative stress in intrauterine fetal deaths in the placenta of the cases examined. In SIUD, the most expressed oxidative stress markers were NOX2 and 8-HODG.

CONCLUSIONS

The study contributes to investigating the role of oxidative stress in modulating different pathways in unexplained intrauterine fetal death (SIUD) tissues.

Clinical and pathological characteristics of gestational diabetes mellitus with different insulin resistance

AIMS

To elucidate the clinical and pathological characteristics of gestational diabetes mellitus (GDM) with high and low insulin resistance.

METHODS

In total, 1393 GDM and 1001 non-GDM singleton deliveries were included in this study. Insulin resistance subtypes were classified according to the HOMA2-IR value. Clinical data were analyzed using SPSS 26.0. Placenta samples were collected for pathological analysis.

RESULTS

Maternal age and fasting glucose were identified as independent risk factors for GDM with high insulin resistance (p < 0.01), while fasting glucose was the sole risk factor for GDM with low insulin resistance (p < 0.001). Fetal distress was associated with both of GDM subtypes (both p < 0.01), while anemia, fetal growth restriction, large for gestational age and intrahepatic cholestasis in pregnancy were related to specific GDM insulin resistance subtype. In addition, GDM with high insulin resistance showed an increase of syncytial knots with down-regulation of PI3K/AKT signaling, while GDM with low insulin resistance showed normal syncytial knot counts and up-regulation of PI3K/AKT signaling.

CONCLUSIONS

Our findings provide novel perspectives to the clinical and pathological comprehensions of GDM with high and low insulin resistance, which might facilitate the mechanism study of GDM and its precision pregnancy management.

The hormonal control of parturition

Parturition is a complex physiological process that must occur in a reliable manner and at an appropriate gestation stage to ensure a healthy newborn and mother. To this end, hormones that affect the function of the gravid uterus, especially progesterone (P4), 17β-estradiol (E2), oxytocin (OT), and prostaglandins (PGs), play pivotal roles. P4 via the nuclear P4 receptor (PR) promotes uterine quiescence and for most of pregnancy exerts a dominant block to labor. Loss of the P4 block to parturition in association with a gain in prolabor actions of E2 are key transitions in the hormonal cascade leading to parturition. P4 withdrawal can occur through various mechanisms depending on species and physiological context. Parturition in most species involves inflammation within the uterine tissues and especially at the maternal-fetal interface. Local PGs and other inflammatory mediators may initiate parturition by inducing P4 withdrawal. Withdrawal of the P4 block is coordinated with increased E2 actions to enhance uterotonic signals mediated by OT and PGs to promote uterine contractions, cervix softening, and membrane rupture, i.e., labor. This review examines recent advances in research to understand the hormonal control of parturition, with focus on the roles of P4, E2, PGs, OT, inflammatory cytokines, and placental peptide hormones together with evolutionary biology of and implications for clinical management of human parturition.

Placental Senescence and the Two-Stage Model of Preeclampsia

In this review, we summarize how an increasingly stressed and aging placenta contributes to the maternal clinical signs of preeclampsia, a potentially lethal pregnancy complication. The pathophysiology of preeclampsia has been conceptualized in the two-stage model. Originally, highlighting the importance of poor placentation for early-onset preeclampsia, the revised two-stage model explains late-onset preeclampsia as well, which is often preceded by normal placentation. We discuss how cellular senescence in the placenta may fit with the framework of the revised two-stage model of preeclampsia pathophysiology and summarize potential cellular and molecular mechanisms, including effects on placental and maternal endothelial function. Cellular senescence may occur in response to inflammatory processes and oxidative, mitochondrial, or endoplasmic reticulum stress and chronic stress induce accelerated, premature placental senescence. In preeclampsia, both circulating and tissue-based senescence markers are present. We suggest that aspirin prophylaxis, commonly recommended from the first trimester onward for women at risk of preeclampsia, may affect placentation and possibly mechanisms of placental senescence, thus attenuating the risk of preeclampsia developing clinically. We propose that biomarkers of placental dysfunction and senescence may contribute to altered preventive strategies, including discontinuation of aspirin at week 24-28 depending on placenta-associated biomarker risk stratification.

Eliminating senescent cells by white adipose tissue-targeted senotherapy alleviates age-related hepatic steatosis through decreasing lipolysis

Cellular senescence is an important risk factor in the development of hepatic steatosis. Senolytics present therapeutic effects on age-related hepatic steatosis without eliminating senescent hepatocytes directly. Therefore, it highlights the need to find senolytics' therapeutic targets. Dysfunction of adipose tissue underlies the critical pathogenesis of lipotoxicity in the liver. However, the correlation between adipose tissue and hepatic steatosis during aging and its underlying molecular mechanism remains poorly understood. We explored the correlation between white adipose tissue (WAT) and the liver during aging and evaluated the effect of lipolysis of aged WAT on hepatic steatosis and hepatocyte senescence. We screened out the ideal senolytics for WAT and developed a WAT-targeted delivery system for senotherapy. We assessed senescence and lipolysis of WAT and hepatic lipid accumulation after treatment. The results displayed that aging accelerated cellular senescence and facilitated lipolysis of WAT. Free fatty acids (FFAs) generated by WAT during aging enhanced hepatic steatosis and induced hepatocyte senescence. The combined usage of dasatinib and quercetin was screened out as the ideal senolytics to eliminate senescent cells in WAT. To minimize non-specific distribution and enhance the effectiveness of senolytics, liposomes decorated with WAT affinity peptide P3 were constructed for senotherapy in vivo. In vivo study, WAT-targeted treatment eliminated senescent cells in WAT and reduced lipolysis, resulting in the alleviation of hepatic lipid accumulation and hepatocyte senescence when compared to non-targeted treatment, providing a novel tissue-targeted, effective and safe senotherapy for age-related hepatic steatosis.

Routine third-trimester ultrasound assessment for intrauterine growth restriction

Intrauterine growth restriction significantly impacts perinatal outcomes. Undetected IUGR escalates the risk of adverse outcomes. Serial symphysis-fundal height measurement, a recommended strategy, is insufficient in detecting abnormal fetal growth. Routine third-trimester ultrasounds significantly improve detection rates compared with this approach, but direct high-quality evidence supporting enhanced perinatal outcomes from routine scanning is lacking. In assessing fetal growth, abdominal circumference alone performs comparably to estimated fetal weight. Hadlock formulas demonstrate accurate fetal weight estimation across diverse gestational ages and settings. When choosing growth charts, prescriptive standards (encompassing healthy pregnancies) should be prioritized over descriptive ones. Customized fetal standards may enhance antenatal IUGR detection, but conclusive high-quality evidence is elusive. Emerging observational data suggest that longitudinal fetal growth assessment could predict adverse outcomes better. However, direct randomized trial evidence supporting this remains insufficient.

Prenatal exposure to air pollution and BWGA Z-score: Modifying effects of placenta leukocyte telomere length and infant sex

BACKGROUND

Air pollutants, such as fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3), have been associated with adverse birth outcomes, including low birth weight, often exhibiting sex-specific effects. However, the modifying effect of placental telomere length (TL), reflecting cumulative lifetime oxidative stress in mothers, remains unexplored.

METHOD

Using data from a Northeastern U.S. birth cohort (n = 306), we employed linear regression and weighted quantile sum models to assess trimester-average air pollution exposures and birth weight for gestational age (BWGA) z-scores. Placental TL, categorized by median split, was considered as an effect modifier. Interactions among air pollutants, placental TL, infant sex, and BWGA z-score were evaluated.

RESULTS

Without placental TL as a modifier, only 1st trimester O3 was significantly associated with BWGA z-scores (coefficient: 0.33, 95% CI: 0.03, 0.63). In models considering TL interactions, a significant modifying effect was observed between 3rd trimester NO2 and BWGA z-scores (interaction p-value = 0.02). Specifically, a one interquartile range (1-IQR) increase in 3rd trimester NO2 was linked to a 0.28 (95% CI: 0.06, 0.52) change in BWGA z-score among shorter placental TL group, with no significant association among longer TL group. Among male infants, there were significant associations between 3rd trimester PM2.5 exposure and BWGA z-scores in the longer TL group (coefficient: -0.34, 95% CI: -0.61, -0.02), and between 1st trimester O3 exposure and BWGA z-scores among males in the shorter TL group (coefficient: 0.59, 95% CI: 0.06, 1.08). For females, only a negative association in 2nd trimester mixture model was observed within the longer TL group (coefficient: -0.10, 95% CI: -0.21, -0.01).

CONCLUSION

These findings highlight the need to consider the complex interactions among prenatal air pollutant exposures, placental TL, and fetal sex to better elucidate those at greatest risk for adverse birth outcomes.

Predicting Time to Delivery in Hypertensive Disorders: Assessing PlGF and sFlt-1 with the Novel Parameter 'Mtp-Multiples of a Normal Term Placenta'

Background: Imbalanced angiogenesis is characteristic of normal placental maturation but it also signals placental dysfunction, underlying hypertensive disorders during pregnancy. This study aimed to investigate the relationship between angiogenic placental aging, measured by markers placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) using the new index "Multiples of a normal term placenta" (Mtp) and the duration of pregnancy. Methods: A retrospective observational study was conducted, including singleton pregnancies diagnosed or suspected of hypertensive disorders after the 20th gestational week. Mtp measures how far a single dosage of angiogenic marker deviates from the expected value in an uncomplicated full-term pregnancy (Mpt = sFlt-1/sFlt-1 reference value or PIGF/PIGF reference value). We considered the 90th, 95th, and 97.5th centiles for sFlt-1 and the 2.5th, 5th, and 10th centiles for PlGF as references. Results: The categories with longer time to delivery, regardless of gestational age, were: Mtp PlGF 10th c ≥ 2, ≥3 and Mtp sFlt-1 90th c ≤ 0.5 (median days of 9, 11, 15 days, respectively). These two categories Mtp sFlt-1 90th c ≥ 3 and Mtp sFlt-1 97.5th c ≥ 2 allow the identification of women at risk for imminent delivery within 1 day. Women who were deemed at low/medium risk based on the sFlt-1/PIGF ratio appeared to be at high risk when considering the individual values of sFlt-1 and/or PIGF. Conclusions: This new Mtp index for sFlt-1 and PlGF could be employed to assess the degree of placental aging in women with hypertensive disorders. It represents a valid tool for evaluating the risk of imminent birth, irrespective of gestational age, surpassing the current stratification based on the sFlt-1/PIGF ratio.

An integral role of mitochondrial function in the pathophysiology of preeclampsia

Preeclampsia (PE) is associated with high maternal and perinatal morbidity and mortality. The development of effective treatment strategies remains a major challenge due to the limited understanding of the pathogenesis. In this review, we summarize the current understanding of PE research, focusing on the molecular basis of mitochondrial function in normal and PE placentas, and discuss perspectives on future research directions. Mitochondria integrate numerous physiological processes such as energy production, cellular redox homeostasis, mitochondrial dynamics, and mitophagy, a selective autophagic clearance of damaged or dysfunctional mitochondria. Normal placental mitochondria have evolved innovative survival strategies to cope with uncertain environments (e.g., hypoxia and nutrient starvation). Cytotrophoblasts, extravillous trophoblast cells, and syncytiotrophoblasts all have distinct mitochondrial morphology and function. Recent advances in molecular studies on the spatial and temporal changes in normal mitochondrial function are providing valuable insight into PE pathogenesis. In PE placentas, hypoxia-mediated mitochondrial fission may induce activation of mitophagy machinery, leading to increased mitochondrial fragmentation and placental tissue damage over time. Repair mechanisms in mitochondrial function restore placental function, but disruption of compensatory mechanisms can induce apoptotic death of trophoblast cells. Additionally, molecular markers associated with repair or compensatory mechanisms that may influence the development and progression of PE are beginning to be identified. However, contradictory results have been obtained regarding some of the molecules that control mitochondrial biogenesis, dynamics, and mitophagy in PE placentas. In conclusion, understanding how the mitochondrial morphology and function influence cell fate decisions of trophoblast cells is an important issue in normal as well as pathological placentation biology. Research focusing on mitochondrial function will become increasingly important for elucidating the pathogenesis and effective treatment strategies of PE.

Expression profile of LncRNA ANRIL, miR-186, miR-181a, and MTMR-3 in patients with preeclampsia

Preeclampsia (PE) is a leading cause of maternal and neonatal morbidity and mortality worldwide. Several studies demonstrated the role of lncRNAs and miRNAs in the pathogenesis of preeclampsia; the aim was to detect the expression profiles of serum LncRNA ANRIL, miR-186, miR-181a, and MTMR-3 in patients with preeclampsia. The study included 160 subjects divided into 80 subjects considered as a control group, 80 patients with preeclampsia. We found that there was a significant difference between the preeclampsia and control groups with up-regulation of miR-186 median (IQR) = 4, 29 (1.35-7.73) (P < 0.0001), miR-181a median (IQR) = 2.45 (0.83-6.52) (P = 0.028), and downregulation of lncRNA ANRIL median (IQR) = 0.35(0.28-0.528) (P < 0.0001), MTMR median (IQR) = 0.32(0.155-1.11), (P < 0.0001). ROC curve of lncRNA ANRIL, miR-186, miR-181a, and MTMR-3 in preeclampsia patients showing the roles of these markers in the diagnosis of preeclampsia. In conclusion, serum LncRNA ANRIL, miR-186, miR-181a, and MTMR-3 could be promising biomarkers in the diagnosis of preeclampsia.

Modified Peptide Molecules As Potential Modulators of Shelterin Protein Functions; TRF1

In this work, we present studies on relatively new and still not well-explored potential anticancer targets which are shelterin proteins, in particular the TRF1 protein can be blocked by in silico designed "peptidomimetic" molecules. TRF1 interacts directly with the TIN2 protein, and this protein-protein interaction is crucial for the proper functioning of telomere, which could be blocked by our novel modified peptide molecules. Our chemotherapeutic approach is based on assumption that modulation of TRF1-TIN2 interaction may be more harmful for cancer cells as cancer telomeres are more fragile than in normal cells. We have shown in vitro within SPR experiments that our modified peptide PEP1 molecule interacts with TRF1, presumably at the site originally occupied by the TIN2 protein. Disturbance of the shelterin complex by studied molecule may not in short term lead to cytotoxic effects, however blocking TRF1-TIN2 resulted in cellular senescence in cellular breast cancer lines used as a cancer model. Thus, our compounds appeared useful as starting model compounds for precise blockage of TRF proteins.

Impact of Aging and Cellular Senescence in the Pathophysiology of Preeclampsia

The incidence of hypertensive disorders of pregnancy is increasing, which may be due to several factors, including an increased age at pregnancy and more comorbid health conditions during reproductive years. Preeclampsia, the most severe hypertensive disorder of pregnancy, has been associated with an increased risk of future disease, including cardiovascular and kidney diseases. Cellular senescence, the process of cell cycle arrest in response to many physiologic and maladaptive stimuli, may play an important role in the pathogenesis of preeclampsia and provide a mechanistic link to future disease. In this article, we will discuss the pathophysiology of preeclampsia, the many mechanisms of cellular senescence, evidence for the involvement of senescence in the development of preeclampsia, as well as evidence that cellular senescence may link preeclampsia to the risk of future disease. Lastly, we will explore how a better understanding of the role of cellular senescence in preeclampsia may lead to therapeutic trials. © 2023 American Physiological Society. Compr Physiol 13:5077-5114, 2023.

The role of placental aging in adverse pregnancy outcomes: A mitochondrial perspective

Premature placental aging is associated with placental insufficiency, which reduces the functional capacity of the placenta, leading to adverse pregnancy outcomes. Placental mitochondria are vital organelles that provide energy and play essential roles in placental development and functional maintenance. In response to oxidative stress, damage, and senescence, an adaptive response is induced to selectively remove mitochondria through the mitochondrial equivalent of autophagy. However, adaptation can be disrupted when mitochondrial abnormalities or dysfunctions persist. This review focuses on the adaptation and transformation of mitochondria during pregnancy. These changes modify placental function throughout pregnancy and can cause complications. We discuss the relationship between placental aging and adverse pregnancy outcomes from the perspective of mitochondria and potential approaches to improve abnormal pregnancy outcomes.

Evidence of Placental Aging in Late SGA, Fetal Growth Restriction and Stillbirth-A Systematic Review

During pregnancy, the placenta undergoes a natural aging process, which is considered normal. However, it has been hypothesized that an abnormally accelerated and premature aging of the placenta may contribute to placenta-related health issues. Placental senescence has been linked to several obstetric complications, including abnormal fetal growth, preeclampsia, preterm birth, and stillbirth, with stillbirth being the most challenging. A systematic search was conducted on Pubmed, Embase, and Scopus databases. Twenty-two full-text articles were identified for the final synthesis. Of these, 15 presented original research and 7 presented narrative reviews. There is a paucity of evidence in the literature on the role of placental aging in late small for gestational age (SGA), fetal growth restriction (FGR), and stillbirth. For future research, guidelines for both planning and reporting research must be implemented. The inclusion criteria should include clear differentiation between early and late SGA and FGR. As for stillbirths, only those with no other known cause of stillbirth should be included in the studies. This means excluding stillbirths due to congenital defects, infections, placental abruption, and maternal conditions affecting feto-maternal hemodynamics.

Role of Inflammaging on the Reproductive Function and Pregnancy

During female lifetime and pregnancy, inflammation and cellular senescence are implicated in physiological processes, from ovulation and menstruation, to placental homeostasis and delivery. Several lifestyles, nutritional, and environmental insults, as well as long-lasting pregestational inflammatory diseases may lead to detrimental effects in promoting and sustaining a chronic excessive inflammatory response and inflammaging, which finally contribute to the decay of fertility and pregnancy outcome, with a negative effect on placental function, fetal development, and future health risk profile in the offspring. Maladaptation to pregnancy and obstetric disease may in turn increase maternal inflammaging in a feedback loop, speeding up aging processes and outbreak of chronic diseases. Maternal inflammaging may also impact, through transgenerational effects, on future adult health. Hence, efficacious interventions should be implemented by physicians and healthcare professionals involved in prevention activities to reduce the modifiable factors contributing to the inflammaging process in order to improve public health.

Cellular senescence in normal and adverse pregnancy

Cellular senescence (CS) is defined as a state of terminal proliferation arrest accompanied by morphological alterations, pro-inflammatory phenotype, and metabolic changes. In recent years, the implications of senescence in numerous physiological and pathological conditions such as development, tissue repair, aging, or cancer have been evident. Some inductors of senescence are tissue repair pathways, telomere shortening, DNA damage, degenerative disorders, and wound healing. Lately, it has been demonstrated that CS plays a decisive role in the development and progression of healthy pregnancy and labor. Premature maternal-fetal tissues senescence (placenta, choriamniotic membranes, and endothelium) is implicated in many adverse pregnancy outcomes, including fetal growth restriction, preeclampsia, preterm birth, and intrauterine fetal death. Here we discuss cellular senescence and its association with normal pregnancy development and adverse pregnancy outcomes. Current evidence allows us to establish the relevance of CS in processes associated with the appropriate development of placentation, the progression of pregnancy, and the onset of labor; likewise, it allows us to understand the undeniable participation of CS deregulation in pathological processes associated with pregnancy.

Senescent cells suppress macrophage-mediated corpse removal via upregulation of the CD47-QPCT/L axis

Progressive accrual of senescent cells in aging and chronic diseases is associated with detrimental effects in tissue homeostasis. We found that senescent fibroblasts and epithelia were not only refractory to macrophage-mediated engulfment and removal, but they also paralyzed the ability of macrophages to remove bystander apoptotic corpses. Senescent cell-mediated efferocytosis suppression (SCES) was independent of the senescence-associated secretory phenotype (SASP) but instead required direct contact between macrophages and senescent cells. SCES involved augmented senescent cell expression of CD47 coinciding with increased CD47-modifying enzymes QPCT/L. SCES was reversible by interfering with the SIRPα-CD47-SHP-1 axis or QPCT/L activity. While CD47 expression increased in human and mouse senescent cells in vitro and in vivo, another ITIM-containing protein, CD24, contributed to SCES specifically in human epithelial senescent cells where it compensated for genetic deficiency in CD47. Thus, CD47 and CD24 link the pathogenic effects of senescent cells to homeostatic macrophage functions, such as efferocytosis, which we hypothesize must occur efficiently to maintain tissue homeostasis.

Heterogenous Differences in Cellular Senescent Phenotypes in Pre-Eclampsia and IUGR following Quantitative Assessment of Multiple Biomarkers of Senescence

Premature ageing of the placenta in pregnancy outcomes is associated with the persistent presence of oxidative stress and placental insufficiency reducing its functional capacity. In this study, we investigated cellular senescence phenotypes of pre-eclampsia and IUGR pregnancies by simultaneously measuring several biomarkers of senescence. Maternal plasma and placental samples were collected at term gestation from nulliparous women undergoing pre-labour elective caesarean section with pre-eclampsia without intrauterine growth restriction (PE; n = 5), pre-eclampsia associated with intrauterine growth restriction (n = 8), intrauterine growth restriction (IUGR < 10th centile; n = 6), and age-matched controls (n = 20). Placental absolute telomere length and senescence gene analysis was performed by RTqPCR. The expression of cyclin-dependent kinase inhibitors (p21 and p16) was determined by Western blot. Senescence-associated secretory phenotypes (SASPs) were evaluated in maternal plasma by multiplex ELISA assay. Placental expression of senescence-associated genes showed significant increases in CHEK1, PCNA, PTEN, CDKN2A, and CCNB-1 (p < 0.05) in pre-eclampsia, while TBX-2, PCNA, ATM, and CCNB-1 expression were evident (p < 0.05) and were significantly decreased in IUGR compared with controls. Placental p16 protein expression was significantly decreased in pre-eclampsia only compared with controls (p = 0.028). IL-6 was significantly increased in pre-eclampsia (0.54 pg/mL ± 0.271 vs. 0.3 pg/mL ± 0.102; p = 0.017) while IFN-γ was significantly increased in IUGR (4.6 pg/mL ± 2.2 vs. 2.17 pg/mL ± 0.8; p = 0.002) compared with controls. These results provide evidence of premature senescence in IUGR pregnancies, and while cell cycle checkpoint regulators are activated in pre-eclampsia, the cellular phenotype is one of cell repair and subsequent proliferation rather than progression to senescence. The heterogeneity of these cellular phenotypes highlights the complexity of characterising cellular senescence and may equally be indicative of the differing pathophysiological insults unique to each obstetric complication.

Are there foetal extracellular vesicles in maternal blood? Prospects for diagnostic biomarker discovery

Prenatal diagnosis of congenital disease improves clinical outcomes; however, as many as 50% of congenital heart disease cases are missed by current ultrasound screening methods. This indicates a need for improved screening technology. Extracellular vesicles (EVs) have attracted enormous interest in recent years for their potential in diagnostics. EVs mediate endocrine signalling in health and disease and are known to regulate aspects of embryonic development. Here, we critically evaluate recent evidence suggesting that EVs released from the foetus are able to cross the placenta and enter the maternal circulation. Furthermore, EVs from the mother appear to be transported in the reverse direction, whilst the placenta itself acts as a source of EVs. Experimental work utilising rodent models employing either transgenically encoded reporters or application of fluorescent tracking dyes provide convincing evidence of foetal-maternal crosstalk. This is supported by clinical data demonstrating expression of placental-origin EVs in maternal blood, as well as limited evidence for the presence of foetal-origin EVs. Together, this work raises the possibility that foetal EVs present in maternal blood could be used for the diagnosis of congenital disease. We discuss the challenges faced by researchers in translating these basic science findings into a clinical non-invasive prenatal test.

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.

LINC00240/miR-155 axis regulates function of trophoblasts and M2 macrophage polarization via modulating oxidative stress-induced pyroptosis in preeclampsia

Background

This study aimed to investigate the effects of LINC00240/miR-155/Nrf2 axis on trophoblast function and macrophage polarization in the pathogenesis of preeclampsia.

Methods

Bindings between LINC00240, miR-155 and Nrf2 were validated by dual luciferase reporter assay or RNA-immunoprecipitation. Cell proliferation, migration, invasion, and pyroptosis were detected by CCK-8, clone formation, wound healing, Transwell system, and flow cytometry, respectively. Macrophage polarization was tested by flow cytometry. The expression levels of LINC00240, miR-155, Nrf2, and oxidative stress and pyroptosis-related markers in in vitro and in vivo preeclampsia models were analyzed by qPCR, western blot, or ELISA assays. Blood pressure, urine protein levels, liver and kidney damages, and trophoblast markers in placenta tissues were further studied in vivo.

Results

Placenta tissues from preeclampsia patients and animals showed decreased LINC00240 and Nrf2 and increased miR-155 expression levels, and the decreased M2 macrophage polarization. LINC00240 directly bound and inhibited expression of miR-155, which then inhibited oxidative stress-induced pyroptosis, promoting proliferation, migration and invasion abilities of trophoblasts, and M2 macrophage polarization. Inhibition of miR-155 led to increased Nrf2 expression and similar changes as LINC00240 overexpression in trophoblast function and macrophage polarization. Overexpression of LINC00240 in in vivo preeclampsia model decreased blood pressure, urine protein, liver and kidney damages, increased fetal weight and length, and induced trophoblast function and M2 macrophage polarization.

Conclusion

LINC00240 inhibited symptoms of preeclampsia through regulation on miR-155/Nrf2 axis, which suppressed oxidative stress-induced pyroptosis to improve trophoblast function and M2 macrophage polarization. LINC00240 could be a potential therapeutic target for preeclampsia.

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.

Telomere fusions as a signal of term placental aging? A pilot study

Lay summary

The placenta plays an essential role at the beginning of life, nourishing and supporting the fetus, but its life span is limited. In late pregnancy, the placenta develops signs of aging, including inflammation and impaired function, which may complicate pregnancy. Placentas also show another sign of aging - cells with extra or missing chromosomes. Chromosomally abnormal cells could gather in the placenta if they get stranded there and/or if the cells do not separate normally. Chromosome separation goes wrong in aging cells when the DNA sequences, which protect the ends of the chromosomes, erode. When chromosomes lose their protective caps, they fuse which leads to abnormal numbers of chromosomes. In this pilot study, for the first time, we found fusions between the caps in a human placenta when it reaches full term. More studies are needed to decide whether this has an influence on how the placenta works and outcomes of pregnancy.

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.

Immunosenescence in atherosclerosis: A role for chronic viral infections

Immune system is a versatile and dynamic body organ which offers survival and endurance of human beings in their hostile living environment. However, similar to other cells, immune cells are hijacked by senescence. The ageing immune cells lose their beneficial functions but continue to produce inflammatory mediators which draw other immune and non-immune cells to the senescence loop. Immunosenescence has been shown to be associated with different pathological conditions and diseases, among which atherosclerosis has recently come to light. There are common drivers of both immunosenescence and atherosclerosis; e.g. inflammation, reactive oxygen species (ROS), chronic viral infections, genomic damage, oxidized-LDL, hypertension, cigarette smoke, hyperglycaemia, and mitochondrial failure. Chronic viral infections induce inflammaging, sustained cytokine signaling, ROS generation and DNA damage which are associated with atherogenesis. Accumulating evidence shows that several DNA and RNA viruses are stimulators of immunosenescence and atherosclerosis in an interrelated network. DNA viruses such as CMV, EBV and HBV upregulate p16, p21 and p53 senescence-associated molecules; induce inflammaging, metabolic reprogramming of infected cells, replicative senescence and telomere shortening. RNA viruses such as HCV and HIV induce ROS generation, DNA damage, induction of senescence-associated secretory phenotype (SASP), metabolic reprogramming of infected cells, G1 cell cycle arrest, telomere shortening, as well as epigenetic modifications of DNA and histones. The newly emerged SARS-CoV-2 virus is also a potent inducer of cytokine storm and SASP. The spike protein of SARS-CoV-2 promotes senescence phenotype in endothelial cells by augmenting p16, p21, senescence-associated β-galactosidase (SA-β-Gal) and adhesion molecules expression. The impact of SARS-CoV-2 mega-inflammation on atherogenesis, however, remains to be investigated. In this review we focus on the common processes in immunosenescence and atherogenesis caused by chronic viral infections and discuss the current knowledge on this topic.

Transcriptomic and histochemical analysis reveal the complex regulatory networks in equine Chorioallantois during spontaneous term labor

The equine chorioallantois (CA) undergoes complex physical and biochemical changes during labor. However, the molecular mechanisms controlling these changes are still unclear. Therefore, the current study aimed to characterize the transcriptome of equine CA during spontaneous labor and compare it to that of normal preterm CA. Placental samples were collected postpartum from mares with normal term labor (TL group, n = 4) and from preterm not in labor mares (330 days GA; PTNL group, n = 4). Our study identified 4137 differentially expressed genes (DEGs) (1820 upregulated and 2317 downregulated) in CA during TL as compared to PTNL. TL was associated with the upregulation of several pro-inflammatory mediators (MHC-I, MHC-II, NLRP3, CXCL8, and MIF). Also, TL was associated with the upregulation of matrix metalloproteinase (MMP1, MMP2, MMP3, and MMP9) with subsequent extracellular matrix degradation and apoptosis, as reflected by upregulation of several apoptosis-related genes (ATF3, ATF4, FAS, FOS, and BIRC3). In addition, TL was associated with downregulation of 21 transcripts coding for collagens. The upregulation of proteases, along with the downregulation of collagens, is believed to be implicated in separation and rupture of the CA during TL. Additionally, TL was associated with downregulation of transcripts coding for proteins essential for progestin synthesis (SRD5A1 and AKR1C1) and angiogenesis (VEGFA and RTL1), as well as upregulation of prostaglandin synthesis-related genes (PTGS2 and PTGES), which could reflect the physiological switch in placental endocrinology and function during TL. In conclusion, our findings revealed the equine CA gene expression signature in spontaneous labor at term, which improves our understanding of the molecular mechanisms triggering labor.

Transcriptional profiles of genes related to mitochondrial aging in placental pathologies

As the placenta develops across gestation, the mitochondria and other organelles like the endoplasmic reticulum (ER) must continue to adapt to stressors such as oxidative stress. As pregnancy approaches term, these stressors may contribute to placental aging, including mitochondrial changes leading to cellular senescence. When these processes are exacerbated, pregnancy pathologies arise. This study aimed to identify correlations between genes related to mitochondria, ER and cellular senescence in placentae complicated by pregnancy complications. Placental samples from pregnancies classified as preterm, term, post-term, preterm with fetal growth restriction (FGR), preterm with preeclampsia (PE) and preterm with PE and FGR were used to measure gene expression of TOMM20, MFN1, TFAM, MFN2, PARK2, PINK1, EIF2AK3, TP53 and ERN1. MetaboAnalyst 5.0 was used to generate heatmaps, principal component analysis (PCA) plots, correlation graphs and receiver operating characteristic (ROC) analysis. This study found that genes related mitochondrial dynamics and aging undergo changes in placentae affected by pregnancy pathologies. The TOMM20/PARK2 ratio may be a promising marker to discriminate between healthy and unhealthy placental tissue. Future studies should explore circulating biomarkers of mitochondrial aging and dysfunction as indicators of placental health.

How trophoblasts fuse: an in-depth look into placental syncytiotrophoblast formation

In humans, cell fusion is restricted to only a few cell types under normal conditions. In the placenta, cell fusion is a critical process for generating syncytiotrophoblast: the giant multinucleated trophoblast lineage containing billions of nuclei within an interconnected cytoplasm that forms the primary interface separating maternal blood from fetal tissue. The unique morphology of syncytiotrophoblast ensures that nutrients and gases can be efficiently transferred between maternal and fetal tissue while simultaneously restricting entry of potentially damaging substances and maternal immune cells through intercellular junctions. To maintain integrity of the syncytiotrophoblast layer, underlying cytotrophoblast progenitor cells terminate their capability for self-renewal, upregulate expression of genes needed for differentiation, and then fuse into the overlying syncytium. These processes are disrupted in a variety of obstetric complications, underscoring the importance of proper syncytiotrophoblast formation for pregnancy health. Herein, an overview of key mechanisms underlying human trophoblast fusion and syncytiotrophoblast development is discussed.

The Achilles' heel of cancer survivors: fundamentals of accelerated cellular senescence

Recent improvements in cancer treatment have increased the lifespan of pediatric and adult cancer survivors. However, cancer treatments accelerate aging in survivors, which manifests clinically as the premature onset of chronic diseases, such as endocrinopathies, osteoporosis, cardiac dysfunction, subsequent cancers, and geriatric syndromes of frailty, among others. Therefore, cancer treatment-induced early aging accounts for significant morbidity, mortality, and health expenditures among cancer survivors. One major mechanism driving this accelerated aging is cellular senescence; cancer treatments induce cellular senescence in tumor cells and in normal, nontumor tissue, thereby helping mediate the onset of several chronic diseases. Studies on clinical monitoring and therapeutic targeting of cellular senescence have made considerable progress in recent years. Large-scale clinical trials are currently evaluating senotherapeutic drugs, which inhibit or eliminate senescent cells to ameliorate cancer treatment-related aging. In this article, we survey the recent literature on phenotypes and mechanisms of aging in cancer survivors and provide an up-to-date review of the major preclinical and translational evidence on cellular senescence as a mechanism of accelerated aging in cancer survivors, as well as insight into the potential of senotherapeutic drugs. However, only with time will the clinical effect of senotherapies on cancer survivors be visible.

The Hypertensive Disorders of Pregnancy: A Focus on Definitions for Clinical Nephrologists

About 5-10% of pregnancies are complicated by one of the hypertensive disorders of pregnancy. The women who experience these disorders have a greater risk of having or developing kidney diseases than women with normotensive pregnancies. While international guidelines do not provide clear indications for a nephrology work-up after pregnancy, this is increasingly being advised by nephrology societies. The definitions of the hypertensive disorders of pregnancy have changed greatly in recent years. The objective of this short review is to gather and comment upon the main definitions of the hypertensive disorders of pregnancy as a support for nephrologists, who are increasingly involved in the short- and long-term management of women with these disorders.

Virus-Induced Membrane Fusion in Neurodegenerative Disorders

A growing body of epidemiological and research data has associated neurotropic viruses with accelerated brain aging and increased risk of neurodegenerative disorders. Many viruses replicate optimally in senescent cells, as they offer a hospitable microenvironment with persistently elevated cytosolic calcium, abundant intracellular iron, and low interferon type I. As cell-cell fusion is a major driver of cellular senescence, many viruses have developed the ability to promote this phenotype by forming syncytia. Cell-cell fusion is associated with immunosuppression mediated by phosphatidylserine externalization that enable viruses to evade host defenses. In hosts, virus-induced immune dysfunction and premature cellular senescence may predispose to neurodegenerative disorders. This concept is supported by novel studies that found postinfectious cognitive dysfunction in several viral illnesses, including human immunodeficiency virus-1, herpes simplex virus-1, and SARS-CoV-2. Virus-induced pathological syncytia may provide a unified framework for conceptualizing neuronal cell cycle reentry, aneuploidy, somatic mosaicism, viral spreading of pathological Tau and elimination of viable synapses and neurons by neurotoxic astrocytes and microglia. In this narrative review, we take a closer look at cell-cell fusion and vesicular merger in the pathogenesis of neurodegenerative disorders. We present a "decentralized" information processing model that conceptualizes neurodegeneration as a systemic illness, triggered by cytoskeletal pathology. We also discuss strategies for reversing cell-cell fusion, including, TMEM16F inhibitors, calcium channel blockers, senolytics, and tubulin stabilizing agents. Finally, going beyond neurodegeneration, we examine the potential benefit of harnessing fusion as a therapeutic strategy in regenerative medicine.

Crosstalk Between Senescent Bone Cells and the Bone Tissue Microenvironment Influences Bone Fragility During Chronological Age and in Diabetes

Bone is a complex organ serving roles in skeletal support and movement, and is a source of blood cells including adaptive and innate immune cells. Structural and functional integrity is maintained through a balance between bone synthesis and bone degradation, dependent in part on mechanical loading but also on signaling and influences of the tissue microenvironment. Bone structure and the extracellular bone milieu change with age, predisposing to osteoporosis and increased fracture risk, and this is exacerbated in patients with diabetes. Such changes can include loss of bone mineral density, deterioration in micro-architecture, as well as decreased bone flexibility, through alteration of proteinaceous bone support structures, and accumulation of senescent cells. Senescence is a state of proliferation arrest accompanied by marked morphological and metabolic changes. It is driven by cellular stress and serves an important acute tumor suppressive mechanism when followed by immune-mediated senescent cell clearance. However, aging and pathological conditions including diabetes are associated with accumulation of senescent cells that generate a pro-inflammatory and tissue-destructive secretome (the SASP). The SASP impinges on the tissue microenvironment with detrimental local and systemic consequences; senescent cells are thought to contribute to the multimorbidity associated with advanced chronological age. Here, we assess factors that promote bone fragility, in the context both of chronological aging and accelerated aging in progeroid syndromes and in diabetes, including senescence-dependent alterations in the bone tissue microenvironment, and glycation changes to the tissue microenvironment that stimulate RAGE signaling, a process that is accelerated in diabetic patients. Finally, we discuss therapeutic interventions targeting RAGE signaling and cell senescence that show promise in improving bone health in older people and those living with diabetes.

Lipids as Regulators of Cellular Senescence

Lipids are key macromolecules that perform a multitude of biological functions ranging from maintaining structural integrity of membranes, energy storage, to signaling molecules. Unsurprisingly, variations in lipid composition and its levels can influence the functional and physiological state of the cell and its milieu. Cellular senescence is a permanent state of cell cycle arrest and is a hallmark of the aging process, as well as several age-related pathologies. Senescent cells are often characterized by alterations in morphology, metabolism, chromatin remodeling and exhibit a complex pro-inflammatory secretome (SASP). Recent studies have shown that the regulation of specific lipid species play a critical role in senescence. Indeed, some lipid species even contribute to the low-grade inflammation associated with SASP. Many protein regulators of senescence have been well characterized and are associated with lipid metabolism. However, the link between critical regulators of cellular senescence and senescence-associated lipid changes is yet to be elucidated. Here we systematically review the current knowledge on lipid metabolism and dynamics of cellular lipid content during senescence. We focus on the roles of major players of senescence in regulating lipid metabolism. Finally, we explore the future prospects of lipid research in senescence and its potential to be targeted as senotherapeutics.