Placental membrane aging and HMGB1 signaling associated with human parturition

Hsa-miR-3928-3p targets the CCL3/CCR5 axis to induce amniotic epithelial cell senescence involved in labor initiation

INTRODUCTION

Senescence in human amniotic epithelial cells (hAECs) and increased sterile inflammation in the amniotic cavity can lead to the initiation of term labor (TL). We investigated the possible roles of hsa-miR-3928-3p and chemokine ligand 3 (CCL3) in labor initiation and the underlying molecular mechanisms.

METHODS

Microarray chip screening was used to analyse the differential expression of miRNAs in amniotic fluid exosomes from women in TL and term not-in-labor. The GEO and miRWalk databases were used to identify differential genes, and a dual luciferase assay was used to verify the relationship. Reverse transcription quantitative PCR (RT-qPCR) and immunofluorescence were used to determine the expression and localization of CCL3/CCR5 in fetal membranes. RT-qPCR and western blotting were used to detect the expression of CCL3/CCR5 in hAECs with hsa-miR-3928-3p knockdown/overexpression. Cell counting kit 8, flow cytometry, EdU proliferation, senescence-associated β-galactosidase, and enzyme-linked immunosorbent assays were performed to detect the impact of hsa-miR-3928-3p on hAEC function.

RESULTS

hsa-miR-3928-3p expression was downregulated in TL. CCL3 (macrophage inflammatory protein-1α) was identified as a differentially expressed target gene. hsa-miR-3928-3p targeted the 3' UTR of CCL3. Downregulation of hsa-miR-3928-3p expression increased CCL3 expression. CCL3, via its CCR5 receptor, decreased the proliferation, but increased the senescence, apoptosis rate, secretion of inflammatory factors (IL-8, TNF-α, and IL-6), and expression of senescence-associated protein p21 in hAECs.

DISCUSSION

hsa-miR-3928-3p negatively regulates CCL3, promoting hAEC senescence through the CCL3-CCR5 axis and inducing signals for labor initiation. These findings provide novel insights for labor initiation in clinical settings.

Role of the GalNAc-galectin pathway in the healing of premature rupture of membranes

BACKGROUND

Premature rupture of the membranes (PROM) is a key cause of preterm birth and represents a major cause of neonatal mortality and morbidity. Natural products N-acetyl-d-galactosamine (GalNAc), which are basic building blocks of important polysaccharides in biological cells or tissues, such as chitin, glycoproteins, and glycolipids, may improve possible effects of wound healing.

METHODS

An in vitro inflammation and oxidative stress model was constructed using tumor necrosis-α (TNF-α) and lipopolysaccharide (LPS) action on WISH cells. Human amniotic epithelial cells (hAECs) were primarily cultured by digestion to construct a wound model. The effects of GalNAc on anti-inflammatory and anti-oxidative stress, migration and proliferation, epithelial-mesenchymal transition (EMT), glycosaminoglycan (GAG)/hyaluronic acid (HA) production, and protein kinase B (Akt) pathway in hAECs and WISH cells were analyzed using the DCFH-DA fluorescent probe, ELISA, CCK-8, scratch, transwell migration, and western blot to determine the mechanism by which GalNAc promotes amniotic wound healing.

RESULTS

GalNAc decreased IL-6 expression in TNF-α-stimulated WISH cells and ROS expression in LPS-stimulated WISH cells (P < 0.05). GalNAc promoted the expression of Gal-1 and Gal-3 with anti-inflammatory and anti-oxidative stress effects. GalNAc promoted the migration of hAECs (50% vs. 80%) and WISH cells through the Akt signaling pathway, EMT reached the point of promoting fetal membrane healing, and GalNAc did not affect the activity of hAECs and WISH cells (P > 0.05). GalNAc upregulated the expression of sGAG in WISH cells (P < 0.05) but did not affect HA levels (P > 0.05).

CONCLUSIONS

GalNAc might be a potential target for the prevention and treatment of PROM through the galectin pathway, including (i) inflammation; (ii) epithelial-mesenchymal transition; (iii) proliferation and migration; and (iv) regression, remodeling, and healing.

High-Throughput 3D-Printed Model of the Feto-Maternal Interface for the Discovery and Development of Preterm Birth Therapies

Spontaneous preterm birth (PTB) affects around 11% of births, posing significant risks to neonatal health due to the inflammation at the fetal-maternal interface (FMi). This inflammation disrupts immune tolerance during pregnancy, often leading to PTB. While organ-on-a-chip (OOC) devices effectively mimic the physiology, pathophysiology, and responses of FMi, their relatively low throughput limits their utility in high-throughput testing applications. To overcome this, we developed a three-dimensional (3D)-printed model that fits in a well of a 96-well plate and can be mass-produced while also accurately replicating FMi, enabling efficient screening of drugs targeting FMi inflammation. Our model features two cell culture chambers (maternal and fetal cells) interlinked via an array of microfluidic channels. It was thoroughly validated, ensuring cell viability, metabolic activity, and cell-specific markers. The maternal chamber was exposed to lipopolysaccharides (LPS) to induce an inflammatory state, and proinflammatory cytokines in the culture supernatant were quantified. Furthermore, the efficacy of anti-inflammatory inhibitors in mitigating LPS-induced inflammation was investigated. Results demonstrated that our model supports robust cell growth, maintains viability, and accurately mimics PTB-associated inflammation. This high-throughput 3D-printed model offers a versatile platform for drug screening, promising advancements in drug discovery and PTB prevention.

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.

Are fetal microchimerism and circulating fetal extracellular vesicles important links between spontaneous preterm delivery and maternal cardiovascular disease risk?

Trafficking and persistence of fetal microchimeric cells (fMCs) and circulating extracellular vesicles (EVs) have been observed in animals and humans, but their consequences in the maternal body and their mechanistic contributions to maternal physiology and pathophysiology are not yet fully defined. Fetal cells and EVs may help remodel maternal organs after pregnancy-associated changes, but the cell types and EV cargos reaching the mother in preterm pregnancies after exposure to various risk factors can be distinct from term pregnancies. As preterm delivery-associated maternal complications are rising, revisiting this topic and formulating scientific questions for future research to reduce the risk of maternal morbidities are timely. Epidemiological studies report maternal cardiovascular risk as one of the major complications after preterm delivery. This paper suggests a potential link between fMCs and circulating EVs and adverse maternal cardiovascular outcomes post-pregnancies, the underlying mechanisms, consequences, and methods for and how this link might be assessed.

Frontiers in the Etiology and Treatment of Preterm Premature Rupture of Membrane: From Molecular Mechanisms to Innovative Therapeutic Strategies

Preterm premature rupture of membranes (pPROM) poses a significant threat to fetal viability and increases the risk for newborn morbidities. The perinatal period of preterm infants affected by pPROM is often characterized by higher rates of mortality and morbidity, with associated risks of cerebral palsy, developmental delays, compromised immune function, respiratory diseases, and sensory impairments. pPROM is believed to result from a variety of causes, including but not limited to microbially induced infections, stretching of fetal membranes, oxidative stress, inflammatory responses, and age-related changes in the fetal-placental interface. Maternal stress, nutritional deficiencies, and medically induced procedures such as fetoscopy are also considered potential contributing factors to pPROM. This comprehensive review explores the potential etiologies leading to pPROM, delves into the intricate molecular mechanisms through which these etiologies cause membrane ruptures, and provides a concise overview of diagnostic and treatment approaches for pPROM. Based on available therapeutic options, this review proposes and explores the possibilities of utilizing a novel composite hydrogel composed of amniotic membrane particles for repairing ruptured fetal membranes, thereby holding promise for its clinical application.

Autophagy Determines Distinct Cell Fates in Human Amnion and Chorion Cells

Human fetal membranes (amniochorion) that line the intrauterine cavity consist of two distinct cell layers; single-layer amnion epithelial cells (AEC) and multilayer chorion trophoblast cells (CTC). These layers are connected through a collagen-rich extracellular matrix. Cellular remodeling helps support membrane growth and integrity during gestation and helps to maintain pregnancy. Preterm prelabor rupture of the human amniochorionic (fetal) membrane (pPROM) is antecedent to 40% of all spontaneous preterm birth. Oxidative stress (OS) induced activation of the p38 MAPK due to various maternal risk exposures and the amniochorion cells' senescence are reported pathological features of pPROM. Our transcriptomics analysis implicated dysregulated autophagy and epithelial-mesenchymal transition (EMT) in fetal membranes from pPROM. The molecular interplay between OS-induced p38 MAPK activation, autophagy, and EMT was investigated in AECs and CTCs to better understand the involvement of autophagy and EMT. We report the differential impact of OS on the autophagic machinery in AECs and CTCs, resulting in distinct cell fates. In AECs, OS-induced p38 MAPK activation causes autophagosome accumulation and reduced autophagic flux mediated by decreased ULK1 activity and kinase activity, leading to senescence. In CTCs, induction of autophagy has a limited effect; however, inhibition of autophagy led to SQSTM1-mediated EMT of trophoblast cells. Autophagy, EMT, and senescence were associated with proinflammatory changes. Thus, AECs and CTCs respond differently to OS via differential autophagy response, partly mediated via p38 MAPK. Besides senescence, OS-induced autophagy dysregulation in amniochorion cells may play a mechanistic role in pPROM pathophysiology.

Relationship among α‑synuclein, aging and inflammation in Parkinson's disease (Review)

Parkinson's disease (PD) is a common neurodegenerative pathology whose major clinical symptoms are movement disorders. The main pathological characteristics of PD are the selective death of dopaminergic (DA) neurons in the pars compacta of the substantia nigra and the presence of Lewy bodies containing α-synuclein (α-Syn) within these neurons. PD is associated with numerous risk factors, including environmental factors, genetic mutations and aging. In many cases, the complex interplay of numerous risk factors leads to the onset of PD. The mutated α-Syn gene, which expresses pathologicalα-Syn protein, can cause PD. Another important feature of PD is neuroinflammation, which is conducive to neuronal death. α-Syn is able to interact with certain cell types in the brain, including through phagocytosis and degradation of α-Syn by glial cells, activation of inflammatory pathways by α-Syn in glial cells, transmission of α-Syn between glial cells and neurons, and interactions between peripheral immune cells and α-Syn. In addition to the aforementioned risk factors, PD may also be associated with aging, as the prevalence of PD increases with advancing age. The aging process impairs the cellular clearance mechanism, which leads to chronic inflammation and the accumulation of intracellular α-Syn, which results in DA neuronal death. In the present review, the age-associated α-Syn pathogenicity and the interactions between α-Syn and certain types of cells within the brain are discussed to facilitate understanding of the mechanisms of PD pathogenesis, which may potentially provide insight for the future clinical treatment of PD.

Blockade of IL-6R prevents preterm birth and adverse neonatal outcomes

BACKGROUND

Preterm birth preceded by spontaneous preterm labour often occurs in the clinical setting of sterile intra-amniotic inflammation (SIAI), a condition that currently lacks treatment.

METHODS

Proteomic and scRNA-seq human data were analysed to evaluate the role of IL-6 and IL-1α in SIAI. A C57BL/6 murine model of SIAI-induced preterm birth was developed by the ultrasound-guided intra-amniotic injection of IL-1α. The blockade of IL-6R by using an aIL-6R was tested as prenatal treatment for preterm birth and adverse neonatal outcomes. QUEST-MRI evaluated brain oxidative stress in utero. Targeted transcriptomic profiling assessed maternal, foetal, and neonatal inflammation. Neonatal biometrics and neurodevelopment were tested. The neonatal gut immune-microbiome was evaluated using metagenomic sequencing and immunophenotyping.

FINDINGS

IL-6 plays a critical role in the human intra-amniotic inflammatory response, which is associated with elevated concentrations of the alarmin IL-1α. Intra-amniotic injection of IL-1α resembles SIAI, inducing preterm birth (7% vs. 50%, p = 0.03, Fisher's exact test) and neonatal mortality (18% vs. 56%, p = 0.02, Mann-Whitney U-test). QUEST-MRI revealed no foetal brain oxidative stress upon in utero IL-1α exposure (p > 0.05, mixed linear model). Prenatal treatment with aIL-6R abrogated IL-1α-induced preterm birth (50% vs. 7%, p = 0.03, Fisher's exact test) by dampening inflammatory processes associated with the common pathway of labour. Importantly, aIL-6R reduces neonatal mortality (56% vs. 22%, p = 0.03, Mann-Whitney U-test) by crossing from the mother to the amniotic cavity, dampening foetal organ inflammation and improving growth. Beneficial effects of prenatal IL-6R blockade carried over to neonatal life, improving survival, growth, neurodevelopment, and gut immune homeostasis.

INTERPRETATION

IL-6R blockade can serve as a strategy to treat SIAI, preventing preterm birth and adverse neonatal outcomes.

FUNDING

NICHD/NIH/DHHS, Contract HHSN275201300006C. WSU Perinatal Initiative in Maternal, Perinatal and Child Health.

Progesterone control of myometrial contractility

During pregnancy, the primary function of the uterus is to be quiescent and not contract, which allows the growing fetus to develop and mature. A uterine muscle layer, myometrium, is composed of smooth muscle cells (SMCs). Before the onset of labor contractions, the uterine SMCs experience a complex biochemical and molecular transformation involving the expression of contraction-associated proteins. Labor is initiated when genes in SMCs are activated in response to a combination of hormonal, inflammatory and mechanical signals. In this review, we provide an overview of molecular mechanisms regulating the process of parturition in humans, focusing on the hormonal control of the myometrium, particularly the steroid hormone progesterone. The primary reason for discussing the regulation of myometrial contractility by progesterone is the importance of the clinical problem of preterm birth. It is thought that the hormonal mechanisms regulating premature uterine contractions represent an untimely triggering of the normal events occurring during term parturition. Yet, our knowledge of the complex and redundant hormonal pathways controlling uterine contractile activity leading to delivery of the neonate remains incomplete. Finally, we introduce recent animal studies using a novel class of drugs, Selective Progesterone Receptor Modulators, targeting progesterone signaling to prevent premature myometrial contractions.

Hypoxia-inducible factor 1 signaling drives placental aging and can provoke preterm labor

Most cases of preterm labor have unknown cause, and the burden of preterm birth is immense. Placental aging has been proposed to promote labor onset, but specific mechanisms remain elusive. We report findings stemming from unbiased transcriptomic analysis of mouse placenta, which revealed that hypoxia-inducible factor 1 (HIF-1) stabilization is a hallmark of advanced gestational timepoints, accompanied by mitochondrial dysregulation and cellular senescence; we detected similar effects in aging human placenta. In parallel in primary mouse trophoblasts and human choriocarcinoma cells, we modeled HIF-1 induction and demonstrated resultant mitochondrial dysfunction and cellular senescence. Transcriptomic analysis revealed that HIF-1 stabilization recapitulated gene signatures observed in aged placenta. Further, conditioned media from trophoblasts following HIF-1 induction promoted contractility in immortalized uterine myocytes, suggesting a mechanism by which the aging placenta may drive the transition from uterine quiescence to contractility at the onset of labor. Finally, pharmacological induction of HIF-1 via intraperitoneal administration of dimethyloxalyl glycine (DMOG) to pregnant mice caused preterm labor. These results provide clear evidence for placental aging in normal pregnancy, and demonstrate how HIF-1 signaling in late gestation may be a causal determinant of the mitochondrial dysfunction and senescence observed within the trophoblast as well as a trigger for uterine contraction.

Development of oxidative stress-associated disease models using feto-maternal interface organ-on-a-chip

Oxidative stress (OS) and inflammation arising from cellular derangements at the fetal membrane-decidual interface (feto-maternal interface [FMi]) is a major antecedent to preterm birth (PTB). However, it is impractical to study OS-associated FMi disease state during human pregnancy, and thus it is difficult to develop strategies to reduce the incidences of PTB. A microfluidic organ-on-chip model (FMi-OOC) that mimics the in vivo structure and functions of FMi in vitro was developed to address this challenge. The FMi-OOC contained fetal (amnion epithelial, mesenchymal, and chorion) and maternal (decidua) cells cultured in four compartments interconnected by arrays of microchannels to allow independent but interconnected co-cultivation. Using this model, we tested the effects of OS and inflammation on both fetal (fetal → maternal) and maternal (maternal → fetal) sides of the FMi and determined their differential impact on PTB-associated pathways. OS was induced using cigarette smoke extract (CSE) exposure. The impacts of OS were assessed by measuring cell viability, disruption of immune homeostasis, epithelial-to-mesenchymal transition (EMT), development of senescence, and inflammation. CSE propagated (LC/MS-MS analysis for nicotine) over a 72-hour period from the maternal to fetal side, or vice versa. However, they caused two distinct pathological effects on the maternal and fetal cells. Specifically, fetal OS induced cellular pathologies and inflammation, whereas maternal OS caused immune intolerance. The pronounced impact produced by the fetus supports the hypothesis that fetal inflammatory response is a mechanistic trigger for parturition. The FMi disease-associated changes identified in the FMi-OOC suggest the unique capability of this in vitro model in testing in utero conditions.

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.

Mitigating Oxidative Stress in Perinatal Cells: A Critical Step toward an Optimal Therapeutic Use in Regenerative Medicine

Oxidative stress (OS) occurs when the production of reactive oxygen species (ROS) is not balanced by the body's antioxidant defense system. OS can profoundly affect cellular health and function. ROS can have a profound negative impact on cells that undergo a predestined and time-regulated process of proliferation or differentiation, such as perinatal stem cells. Due to the large-scale employment of these immunotolerant stem cells in regenerative medicine, it is important to reduce OS to prevent them from losing function and increase their application in the regenerative medicine field. This goal can be achieved through a variety of strategies, such as the use of antioxidants and other compounds that can indirectly modulate the antioxidant defense system by enhancing cellular stress response pathways, including autophagy and mitochondrial function, thereby reducing ROS levels. This review aims to summarize information regarding OS mechanisms in perinatal stem cells and possible strategies for reducing their deleterious effects.

Early Environment and Telomeres: a Long-Term Toxic Relationship

PURPOSE OF REVIEW

Telomere length (TL) shortening is a hallmark of biological aging. While studies have extensively focused on the impact of environmental exposures on TL in older populations, consistent evidence indicates that prenatal environmental exposures to air pollutants, polycyclic aromatic hydrocarbons, metals, and endocrine-disrupting chemicals influence TL shortening. Here, we summarize evidence linking prenatal environmental exposures with children's TL and discuss potential long-term effects.

RECENT FINDINGS

Current evidence shows that prenatal environmental exposures alter TL and identify pregnancy as a critical window of susceptibility for telomere damage in children. However, results vary across studies, possibly depending on the source, exposure time window, and stage evaluated. Additional research is needed to investigate whether early TL alterations mediate long-term health effects of offspring. Prenatal environmental exposures induce early childhood changes in TL. Based on known links between TL and biological aging, these alterations may have long-term impact on individuals' health throughout life.

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.

Amnion-derived serum amyloid A1 participates in sterile inflammation of fetal membranes at parturition

OBJECTIVES

Sterile inflammation of fetal membranes is an indispensable event of normal parturition. However, triggers of sterile inflammation are not fully resolved. Serum amyloid A1 (SAA1) is an acute phase protein produced primarily by the liver. Fetal membranes can also synthesize SAA1 but its functions are not well defined. Given the role of SAA1 in the acute phase response to inflammation, we postulated that SAA1 synthesized in the fetal membranes may be a trigger of local inflammation at parturition.

METHODS

The changes of SAA1 abundance in parturition were studied in the amnion of human fetal membranes. The role of SAA1 in chemokine expression and leukocyte chemotaxis was examined in cultured human amnion tissue explants as well as primary human amnion fibroblasts. The effects of SAA1 on monocytes, macrophages and dendritic cells were investigated in cells derived from a human leukemia monocytic cell line (THP-1).

RESULTS

SAA1 synthesis increased significantly in human amnion at parturition. SAA1 evoked multiple chemotaxis pathways in human amnion fibroblasts along with upregulation of a series of chemokines via both toll-like receptor 4 (TLR4) and formyl peptide receptor 2 (FPR2). Moreover, SAA1-conditioned medium of cultured amnion fibroblasts was capable of chemoattracting virtually all types of mononuclear leukocytes, particularly monocytes and dendritic cells, which reconciled with the chemotactic activity of conditioned medium of cultured amnion tissue explants collected from spontaneous labor. Furthermore, SAA1 could induce the expression of genes associated with inflammation and extracellular matrix remodeling in monocytes, macrophages and dendritic cells derived from THP-1.

CONCLUSIONS

SAA1 is a trigger of sterile inflammation of the fetal membranes at parturition.

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.

The serotonin reuptake inhibitor fluoxetine induces human fetal membrane sterile inflammation through p38 MAPK activation

Serotonin Reuptake Inhibitors (SRIs) are often used as first line therapy for depression and other psychiatric disorders. SRI use during pregnancy is associated with preterm premature rupture of membranes (PPROM) and subsequent preterm birth. The objective of this study was to investigate the mechanism(s) responsible for SRI-associated PPROM. Putative mechanisms underlying PPROM include fetal membrane (FM) inflammation, increased apoptosis, and/or accelerated senescence, the later which may be reversed by statins. Human FM explants from normal term deliveries without labor, infection, or antidepressant use were treated with or without the SRI, fluoxetine (FLX), either alone or in the presence of a p38 MAPK inhibitor or the statins, simvastatin or rosuvastatin. FMs were also collected from women either unexposed or exposed to FLX during pregnancy. FLX significantly increased FM p38 MAPK activity and secretion of inflammatory IL-6. Inhibition of p38 MAPK reduced FM IL-6 secretion in response to FLX. Statins did not reduce the SRI-induced FM IL-6 production. FMs from women exposed to FLX during pregnancy expressed elevated levels of p38 MAPK activity compared to matched unexposed women. FMs exposed to FLX did not exhibit signs of increased apoptosis and/or accelerated senescence. These results indicate that the SRI, FLX, may induce sterile FM inflammation during pregnancy through activation of the p38 MAPK pathway, and in the absence of apoptosis and senescence. These findings may better inform clinicians and patients as they weigh the risks and benefits of SRI antidepressant treatment during pregnancy.

The Role of Fetal Membranes during Gestation, at Term, and Preterm Labor

During pregnancy, the fetal membranes (i.e., amniochorionic membranes) surround the intrauterine cavity and provide mechanical, immune, and endocrine support to protect the fetus. Though they are a vital component of the intrauterine cavity, the fetal membranes are largely overlooked as an extension of the placenta, leading to a poor understanding of their role during gestation, parturition, or preterm birth. The fetal membranes are comprised of fetal cellular and stromal layers and line up with maternal decidua forming the feto-maternal interface during pregnancy. This interface plays a large role during pregnancy and the induction of term or preterm parturition (e.g., labor). Here we summarize the function of the fetal membranes focusing on their role during gestation at term, and during preterm births.

Is human labor at term an inflammatory condition?†

Parturition at term in normal pregnancy follows a predictable sequence of events. There is some evidence that a state of inflammation prevails in the reproductive tissues during labor at term, but it is uncertain whether this phenomenon is the initiating signal for parturition. The absence of a clear temporal sequence of inflammatory events prior to labor casts doubt on the concept that normal human labor at term is primarily the result of an inflammatory cascade. This review examines evidence linking parturition and inflammation in order to address whether inflammation is a cause of labor, a consequence of labor, or a separate but related phenomenon. Finally, we identify and suggest ways to reconcile inconsistencies regarding definitions of labor onset in published research, which may contribute to the variability in conclusions regarding the genesis and maintenance of parturition. A more thorough understanding of the processes underlying normal parturition at term may lead to novel insights regarding abnormal labor, including spontaneous preterm labor, preterm premature rupture of the fetal membranes, and dysfunctional labor, and the role of inflammation in each.

Silencing P38 MAPK reduces cellular senescence in human fetal chorion trophoblast cells

PROBLEM

Amniochorion senescence generates mechanistic signals to initiate parturition. Activation of p38 mitogen-activated kinase (MAPK) in fetal amnion cells is a key mediator of senescence as well as epithelial-mesenchymal transition (EMT) of amnion cells. However, the impact of p38 MAPK in chorion trophoblast cells (CTCs) is unclear. We tested if eliminating p38 will reduce oxidative stress (OS) induced cell fates like cellular senescence, EMT, and inflammation induced by these processes in CTCs.

METHODS

p38MAPK in CTCs was silenced using CRISPR/Cas9. OS was evoked by cigarette smoke extract (CSE) exposure. EMT was evoked by transforming growth factor (TGF)-ß treatment. Cell cycle, senescence, EMT, and inflammation were analyzed.

RESULTS

CSE-induced changes in the cell cycle were not seen in p38KO CTCs compared to WT cells. OS induced by CSE evoked senescence and senescence-associated secretory phenotype (SASP as indicated by IL-6 and IL-8 increase) in WT but not in p38MAPK KO CTCs. No changes were noted in HLA-G expression regardless of the status of p38MAPK. Neither CSE nor TGF-ß evoked EMT in either WT or p38 KO CTCs.

CONCLUSION

Senescence and senescence-associated inflammation in human fetal CTCs are mediated by p38MAPK. Compared to amnion epithelial cells, CTCs are resistant to EMT. This refractoriness may help them to maintain the barrier functions at the choriodecidual interface.

Targeting cellular senescence in metabolic disease

Cellular senescence is a cell fate involving cell cycle arrest, resistance against apoptosis, and the development of a secretome that can be pro-inflammatory. In aging and obesity, senescent cells accumulate in many tissues, including adipose tissue, brain, kidney, pancreas, and liver. These senescent cells and their downstream effects appear to perpetuate inflammation and have been implicated in the pathogenesis of metabolic dysfunction. Senescent cells are cleared in part by the immune system, a process that is diminished in obesity and aging, likely due in part to senescence of immune cells themselves. Targeting senescent cells or their products improves metabolic function in both aging and in animal models of obesity. Novel therapeutics to target senescent cells are on the horizon and are currently being investigated in clinical trials in humans for multiple diseases. Early evidence suggests that senolytic drugs, which transiently disarm the anti-apoptotic defenses of pro-inflammatory senescent cells, are effective in causing depletion of senescent cells in humans. Senescence-targeting therapeutics, including senolytic drugs and strategies to increase immune clearance of senescent cells, hold significant promise for treating metabolic dysfunction in multiple tissues and disease states.

Transcriptomic analysis of the human placenta reveals trophoblast dysfunction and augmented Wnt signalling associated with spontaneous preterm birth

Preterm birth (PTB) is the leading cause of death in under-five children. Worldwide, annually, over 15 million babies are born preterm and 1 million of them die. The triggers and mechanisms of spontaneous PTB remain largely unknown. Most current therapies are ineffective and there is a paucity of reliable predictive biomarkers. Understanding the molecular mechanisms of spontaneous PTB is crucial for developing better diagnostics and therapeutics. To address this need, we conducted RNA-seq transcriptomic analysis, qRT-PCR and ELISA on fresh placental villous tissue from 20 spontaneous preterm and 20 spontaneous term deliveries, to identify genes and signalling pathways involved in the pathogenesis of PTB. Our differential gene expression, gene ontology and pathway analysis revealed several dysregulated genes (including OCLN, OPTN, KRT7, WNT7A, RSPO4, BAMBI, NFATC4, SLC6A13, SLC6A17, SLC26A8 and KLF8) associated with altered trophoblast functions. We identified dysregulated Wnt, oxytocin and cellular senescence signalling pathways in preterm placentas, where augmented Wnt signalling could play a pivotal role in the pathogenesis of PTB due to its diverse biological functions. We also reported two novel targets (ITPR2 and MYLK2) in the oxytocin signalling pathways for further study. Through bioinformatics analysis on DEGs, we identified four key miRNAs, - miR-524-5p, miR-520d-5p, miR-15a-5p and miR-424-5p - which were significantly downregulated in preterm placentas. These miRNAs may have regulatory roles in the aberrant gene expressions that we have observed in preterm placentas. We provide fresh molecular insight into the pathogenesis of spontaneous PTB which may drive further studies to develop new predictive biomarkers and therapeutics.

Spontaneous preterm birth: Involvement of multiple feto-maternal tissues and organ systems, differing mechanisms, and pathways

Survivors of preterm birth struggle with multitudes of disabilities due to improper in utero programming of various tissues and organ systems contributing to adult-onset diseases at a very early stage of their lives. Therefore, the persistent rates of low birth weight (birth weight < 2,500 grams), as well as rates of neonatal and maternal morbidities and mortalities, need to be addressed. Active research throughout the years has provided us with multiple theories regarding the risk factors, initiators, biomarkers, and clinical manifestations of spontaneous preterm birth. Fetal organs, like the placenta and fetal membranes, and maternal tissues and organs, like the decidua, myometrium, and cervix, have all been shown to uniquely respond to specific exogenous or endogenous risk factors. These uniquely contribute to dynamic changes at the molecular and cellular levels to effect preterm labor pathways leading to delivery. Multiple intervention targets in these different tissues and organs have been successfully tested in preclinical trials to reduce the individual impacts on promoting preterm birth. However, these preclinical trial data have not been effectively translated into developing biomarkers of high-risk individuals for an early diagnosis of the disease. This becomes more evident when examining the current global rate of preterm birth, which remains staggeringly high despite years of research. We postulate that studying each tissue and organ in silos, as how the majority of research has been conducted in the past years, is unlikely to address the network interaction between various systems leading to a synchronized activity during either term or preterm labor and delivery. To address current limitations, this review proposes an integrated approach to studying various tissues and organs involved in the maintenance of normal pregnancy, promotion of normal parturition, and more importantly, contributions towards preterm birth. We also stress the need for biological models that allows for concomitant observation and analysis of interactions, rather than focusing on these tissues and organ in silos.

Deciphering the endometrial immune landscape of RIF during the window of implantation from cellular senescence by integrated bioinformatics analysis and machine learning

Recurrent implantation failure (RIF) is an extremely thorny issue in in-vitro fertilization (IVF)-embryo transfer (ET). However, its intricate etiology and pathological mechanisms are still unclear. Nowadays, there has been extensive interest in cellular senescence in RIF, and its involvement in endometrial immune characteristics during the window of implantation (WOI) has captured scholars' growing concerns. Therefore, this study aims to probe into the pathological mechanism of RIF from cellular senescence and investigate the correlation between cellular senescence and endometrial immune characteristics during WOI based on bioinformatics combined with machine learning strategy, so as to elucidate the underlying pathological mechanisms of RIF and to explore novel treatment strategies for RIF. Firstly, the gene sets of GSE26787 and GSE111974 from the Gene Expression Omnibus (GEO) database were included for the weighted gene correlation network analysis (WGCNA), from which we concluded that the genes of the core module were closely related to cell fate decision and immune regulation. Subsequently, we identified 25 cellular senescence-associated differentially expressed genes (DEGs) in RIF by intersecting DEGs with cellular senescence-associated genes from the Cell Senescence (CellAge) database. Moreover, functional enrichment analysis was conducted to further reveal the specific molecular mechanisms by which these molecules regulate cellular senescence and immune pathways. Then, eight signature genes were determined by the machine learning method of support vector machine-recursive feature elimination (SVM-RFE), random forest (RF), and artificial neural network (ANN), comprising LATS1, EHF, DUSP16, ADCK5, PATZ1, DEK, MAP2K1, and ETS2, which were also validated in the testing gene set (GSE106602). Furthermore, distinct immune microenvironment abnormalities in the RIF endometrium during WOI were comprehensively explored and validated in GSE106602, including infiltrating immunocytes, immune function, and the expression profiling of human leukocyte antigen (HLA) genes and immune checkpoint genes. Moreover, the correlation between the eight signature genes with the endometrial immune landscape of RIF was also evaluated. After that, two distinct subtypes with significantly distinct immune infiltration characteristics were identified by consensus clustering analysis based on the eight signature genes. Finally, a "KEGG pathway-RIF signature genes-immune landscape" association network was constructed to intuitively uncover their connection. In conclusion, this study demonstrated that cellular senescence might play a pushing role in the pathological mechanism of RIF, which might be closely related to its impact on the immune microenvironment during the WOI phase. The exploration of the molecular mechanism of cellular senescence in RIF is expected to bring new breakthroughs for disease diagnosis and treatment strategies.

Fetal Lung-Derived Exosomes in Term Labor Amniotic Fluid Induce Amniotic Membrane Senescence

The mechanism of parturition is still unclear. Evidence has shown that delivery is associated with cellular senescence of the amniotic membrane. We isolated fetal lung-associated exosomes from the amniotic fluid from term labor (TL-exos) and verified that the exosomes can cause primary human amniotic epithelial cell (hAEC) senescence and apoptosis and can release higher levels of senescence-associated secretory phenotype (SASP)-related molecules and proinflammatory damage-associated molecular patterns (DAMPs) than exosomes isolated from the amniotic fluid from term not in labor (TNIL-exos). The human lung carcinoma cell lines (A549) can be used as an alternative to alveolar type 2 epithelial cells producing pulmonary surfactant. Therefore, we isolated A549 cell-derived exosomes (A549-exos) and found that they can trigger hAEC to undergo the same aging process. Finally, the animal experiments suggested that A549-exos induced vaginal bleeding and preterm labor in pregnant mice. Therefore, we conclude that exosomes derived from fetal lungs in term labor amniotic fluid induce amniotic membrane senescence, which may provide new insight into the mechanism of delivery.

Fetal DNA Causes Sex-Specific Inflammation From Human Fetal Membranes

Inflammation is central to the mechanisms of parturition, but the lack of understanding of how it is controlled in normal parturition hampers our ability to understand how it may diverge resulting in preterm birth. Cell-free fetal DNA is found in the amniotic fluid, and it is thought to be able to activate inflammation as a danger-associated molecular pattern. Although its levels increases with gestational age, its effect has not been studied on the human fetal membranes. Thus, the aim of this study was to determine if the fetal DNA can trigger inflammation in the human fetal membranes and, thus, potentially contribute to the inflammatory load. Isolated human amniotic epithelial cells and fetal membrane explants were treated apically with fetal DNA causing the translocation of NF-KB into the nucleus of cells and throughout the cells of the explant layers with time. Fetal membrane explants were treated apically with either small or larger fragments of fetal DNA. IL-6, TNFα, and GM-CSF secretion was measured by ELISA, and pro-MMP2 and pro-MMP9 activity was measured by zymography from apical and basal media. Increased apical IL-6 secretion and basal pro-MMP2 activity was seen with small fragments of fetal DNA. When the data were disaggregated based on fetal sex, males had significant increases in IL-6 secretion and basal increased activity in pro-MMP2 and 9, whereas females had significantly increased basal secretion of TNFα. This was caused by the smaller fragments of fetal DNA, whereas the larger fragments did not cause any significant increases. Male fetal DNA had significantly lower percentages of methylation than females. Thus, when the cytokine and pro-MMP activity data were correlated with methylation percentage, IL-6 secretion significantly correlated negatively, whereas GM-CSF secretion positively correlated. These data support the role of fetal DNA as an inflammatory stimulus in the FM, as measured by increased NF-κB translocation, cytokine secretion, and increased pro-MMP activity. However, the data also suggested that the responses are different from FM tissues of male and female fetuses, and both the fragment size and methylation status of the fetal DNA can influence the magnitude and type of molecule secreted.

The immunobiology of preterm labor and birth: intra-amniotic inflammation or breakdown of maternal-fetal homeostasis

In brief

The syndrome of preterm labor comprises multiple established and novel etiologies. This review summarizes the distinct immune mechanisms implicated in preterm labor and birth and highlights potential strategies for its prevention.

Abstract

Preterm birth, the leading cause of neonatal morbidity and mortality worldwide, results from preterm labor, a syndrome that includes multiple etiologies. In this review, we have summarized the immune mechanisms implicated in intra-amniotic inflammation, the best-characterized cause of preterm labor and birth, as well as novel etiologies non-associated with intra-amniotic inflammation (i.e. formally known as idiopathic). While the intra-amniotic inflammatory responses driven by microbes (infection) or alarmins (sterile) have some overlap in the participating cellular and molecular processes, the distinct natures of these two conditions necessitate the implementation of specific approaches to prevent adverse pregnancy and neonatal outcomes. Intra-amniotic infection can be treated with the correct antibiotics, whereas sterile intra-amniotic inflammation could potentially be treated by administering a combination of anti-inflammatory drugs (e.g. betamethasone, inflammasome inhibitors, etc.). Recent evidence also supports the role of fetal T-cell activation as a newly described trigger for preterm labor and birth in a subset of cases diagnosed as idiopathic. Moreover, herein we also provide evidence of two maternally-driven immune mechanisms responsible for preterm births formerly considered to be idiopathic. First, the impairment of maternal Tregs can lead to preterm birth, likely due to the loss of immunosuppressive activity resulting in unleashed effector T-cell responses. Secondly, homeostatic macrophages were shown to be essential for maintaining pregnancy and promoting fetal development, and the adoptive transfer of homeostatic M2-polarized macrophages shows great promise for preventing inflammation-induced preterm birth. Collectively, in this review, we discuss the established and novel immune mechanisms responsible for preterm birth and highlight the potential targets for novel strategies aimed at preventing the multi-etiological syndrome of preterm labor leading to preterm birth.

Prenatal lead exposure, telomere length in cord blood, and DNA methylation age in the PROGRESS prenatal cohort

BACKGROUND

Lead is a ubiquitous pollutant with deleterious effects on human health and remains a major current public health concern in developing countries. This heavy metal may interfere with nucleic acids via oxidative stress or epigenetic changes that affect biological markers of aging, e.g., telomere length and DNA methylation (DNAm). Telomere shortening associates with biological age in newborns, and DNA methylation at specific CpG sites can be used to calculate "epigenetic clocks".

OBJECTIVE

The aim of this study was to examine the associations of prenatal lead exposures with telomere length and DNA-methylation-based predictors of age in cord blood.

DESIGN

The study included 507 mother-child pairs from the Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) study, a birth cohort in Mexico City. Maternal blood (second trimester, third trimester and at delivery) and bone lead levels (one month postpartum) were measured using inductively coupled plasma-mass spectrometry and X-ray fluorescence, respectively. Cord blood leukocyte telomere length was measured using quantitative PCR and apparent age by DNA methylation biomarkers, i.e., Horvath's DNA methylation age and the Knight's predictor of gestational age.

RESULTS

Average maternal age was 28.5 ± 5.5 years, and 51.5% reported low socioeconomic status. Children's mean telomere length was 1.2 ± 1.3 relative units, and mean DNA methylation ages using the Horvath's and Knight's clocks were -2.6 ± 0.1 years and 37.9 ± 1.4 weeks (mean ± SD), respectively. No significant associations were found between maternal blood and bone lead concentrations with telomere length and DNAm age in newborns.

CONCLUSION

We found no associations of prenatal lead exposure with telomere length and DNA methylation age biomarkers.

The role of cellular senescence in female reproductive aging and the potential for senotherapeutic interventions

BACKGROUND

Advanced maternal age is associated with decreased oocyte quantity and quality as well as uterine and placental dysfunctions. These changes lead to infertility, pregnancy complications and birth defects in the offspring. As the mean age of giving birth is increasing worldwide, prevention of age-associated infertility and pregnancy complications, along with the more frequent use of ART, become extremely important. Currently, significant research is being conducted to unravel the mechanisms underlying female reproductive aging. Among the potential mechanisms involved, recent evidence has suggested a contributing role for cellular senescence, a cellular state of irreversible growth arrest characterized by a hypersecretory and pro-inflammatory phenotype. Elucidating the role of senescence in female reproductive aging holds the potential for developing novel and less invasive therapeutic measures to prevent or even reverse female reproductive aging and increase offspring wellbeing.

OBJECTIVE AND RATIONALE

The review will summarize the positive and negative implications of cellular senescence in the pathophysiology of the female reproductive organs during aging and critically explore the use of novel senotherapeutics aiming to reverse and/or eliminate their detrimental effects. The focus will be on major senescence mechanisms of the ovaries, the uterus, and the placenta, as well as the potential and risks of using senotherapies that have been discovered in recent years.

SEARCH METHODS

Data for this review were identified by searches of MEDLINE, PubMed and Google Scholar. References from relevant articles using the search terms 'Cellular Senescence', 'Aging', 'Gestational age', 'Maternal Age', 'Anti-aging', 'Uterus', 'Pregnancy', 'Fertility', 'Infertility', 'Reproduction', 'Implant', 'Senolytic', 'Senostatic', 'Senotherapy' and 'Senotherapeutic' where selected. A total of 182 articles published in English between 2005 and 2020 were included, 27 of which focus on potential senotherapies for reproductive aging. Exclusion criteria were inclusion of the terms 'male' and 'plants'.

OUTCOMES

Aging is a major determinant of reproductive wellbeing. Cellular senescence is a basic aging mechanism, which can be exploited for therapeutic interventions. Within the last decade, several new strategies for the development and repurposing of drugs targeting senescent cells have emerged, such as modulators of the anti-inflammatory response, oxidative stress, DNA damage, and mitochondria and protein dysfunctions. Several studies of female reproductive aging and senotherapies have been discussed that show promising results for future interventions.

WIDER IMPLICATIONS

In most countries of the Organization for Economic Co-operation and Development, the average age at which women give birth is above 30 years. Currently, in countries such as the Netherlands, Australia, Spain, Finland, Germany and the UK, birth rates among 30- to 34-year-olds are now higher than in any other age groups. This review will provide new knowledge and scientific advancement on the senescence mechanisms during female reproductive aging, and benefit fundamental and clinical scientists and professionals in the areas of reproduction, cancer, immunobiology and fibrosis.

Correlation of HMGB1, PON-1, MCP-1, and Periodontal P. gingivalis with Amniotic Fluid Fecal Dye

BACKGROUND

This paper aims to investigate the correlation between high mobility group protein-1 (HMG-b1), antioxidant enzyme-1 (paraoxon-1, PON-1), monocyte chemoattractant protein-1 (monocyte chemoattractant protein-1, MCP-1), P. gingivalis, and MSAF.

MATERIALS AND METHODS

The total sample size comprised of 73 cases in both groups. These patients were further subdivided into 2 groups: the MSAF group and the control group. 38 women were in the MSAF group and 35 women with term amniotic fluid serum were in the control group. The MSAF group was selected as a full-term singleton amniotic fluid fecal infection group. Clinical data were collected, and specimens were collected. Fecal staining of amniotic fluid and full-term amniotic fluid removes the placenta and umbilical cord blood. The expression of HMGB1 in the placenta was observed by immune-histochemical staining of MSAF and control groups. The content of PON-1 in cord blood was determined by ELISA.

RESULTS

Correlation between maternal and neonatal clinical data and MSAF was done; MSAF group mean gestational age was 41.38 ± 1.40 weeks; control group mean gestational age was 39.20 ± 1.24 weeks. This study found no correlation between the birth weight, maternal age, sex, first/transmaternal, hyperthyroidism, hypothyroidism, and anemia between the MSAF and control group with nonsignificant P value (P > 0.05). However, the fatal age, gestational diabetes, gestational hypertension, umbilical cord abnormalities, placental abnormalities, and neonatal asphyxia factors were statistically different with a significant P value of <0.05 between both groups. HMGB1 and Periodontal P. gingivalis are mostly expressed in placental trophoblast, vascular endothelial cells, and amniotic epithelial and interstitial cells. After HE staining of 72 placentas by HE in MSAF and control, 6 had acute chorioamnionitis (5.1 control), 32 had chronic (23.9), 35 had abnormal placentas, and three in MSAF had chorionic columnar metaplasia. In immune-histochemistry experiments, the HMGB1 expression intensity of placental tissue was higher in the MSAF group (P < 0.05); however, the level of PON-1 was lower in the MSAF group as compared to the controls (P < 0.05).

CONCLUSIONS

Gestational age and placental abnormalities are clinical high-risk factors for MSAF. HMGB1, PON-1, MCP-1, and Periodontal P. gingivalis may be involved in the development of MSAF, suggesting an oxidative/antioxidant imbalance with inflammation, and may be one of the mechanisms for MSAF development.

Generation and characterization of human Fetal membrane and Decidual cell lines for reproductive biology experiments†

Human fetal membrane and maternal decidua parietalis form one of the major feto-maternal interfaces during pregnancy. Studies on this feto-maternal interface is limited as several investigators have limited access to the placenta, and experience difficulties to isolate and maintain primary cells. Many cell lines that are currently available do not have the characteristics or properties of their primary cells of origin. Therefore, we created, characterized the immortalized cells from primary isolates from fetal membrane-derived amnion epithelial cells, amnion and chorion mesenchymal cells, chorion trophoblast cells and maternal decidua parietalis cells. Primary cells were isolated from a healthy full-term, not in labor placenta. Primary cells were immortalized using either a HPV16E6E7 retroviral or a SV40T lentiviral system. The immortalized cells were characterized for the morphology, cell type-specific markers, and cell signalling pathway activation. Genomic stability of these cells was tested using RNA seq, karyotyping, and short tandem repeats DNA analysis. Immortalized cells show their characteristic morphology, and express respective epithelial, mesenchymal and decidual markers similar to that of primary cells. Gene expression of immortalized and primary cells were highly correlated (R = 0.798 to R = 0.974). Short tandem repeats DNA analysis showed in the late passage number (>P30) of cell lines matched 84-100% to the early passage number (<P10) of the cell lines revealing there were no genetic drift over the passages. Karyotyping also revealed no chromosomal anomalies. Creation of these cell lines can standardize experimental approaches, eliminate subject to subject variabilities, and benefit the reproductive biological studies on pregnancies by using these cells.

Extracellular vesicles from maternal uterine cells exposed to risk factors cause fetal inflammatory response

Background

Fetal cell-derived exosomes (extracellular vesicles, 40–160 nm) are communication channels that can signal parturition by inducing inflammatory changes in maternal decidua and myometrium. Little is known about maternal cell-derived exosomes and their functional roles on the fetal side. This study isolated and characterized exosomes from decidual and myometrial cells grown under normal and inflammatory/oxidative stress conditions and determined their impact on fetal membrane cells.

Methods

Decidual and myometrial cells were grown under standard culture conditions (control) or exposed for 48 h to cigarette smoke extract or tumor necrosis factor-α, as proxies for oxidative stress and inflammation, respectively. Exosomes were isolated from media (differential ultra-centrifugation followed by size exclusion chromatography), quantified (nano particle tracking analysis), and characterized in terms of their size and morphology (cryo-electron microscopy), markers (dot blot), and cargo contents (proteomics followed by bioinformatics analysis). Maternal exosomes (10⁹/mL) were used to treat amnion epithelial cells and chorion trophoblast cells for 24 h. The exosome uptake by fetal cells (confocal microscopy) and the cytokine response (enzyme-linked immunosorbent assays for IL-6, IL-10, and TNF-α) was determined.

Results

Exosomes from both decidual and myometrial cells were round and expressed tetraspanins and endosomal sorting complexes required for transport (ESCRT) protein markers. The size and quantity was not different between control and treated cell exosomes. Proteomic analysis identified several common proteins in exosomes, as well as unique proteins based on cell type and treatment. Compared to control exosomes, pro-inflammatory cytokine release was higher in both amnion epithelial cell and chorion trophoblast cell media when the cells had been exposed to exosomes from decidual or myometrial cells treated with either cigarette smoke extract or tumor necrosis factor-α. In chorion trophoblast cells, anti-inflammatory IL-10 was increased by exosomes from both decidual and myometrial cells.

Conclusion

Various pathophysiological conditions cause maternal exosomes to carry inflammatory mediators that can result in cell type dependent fetal inflammatory response.

The metabolic roots of senescence: mechanisms and opportunities for intervention

Cellular senescence entails a permanent proliferative arrest, coupled to multiple phenotypic changes. Among these changes is the release of numerous biologically active molecules collectively known as the senescence-associated secretory phenotype, or SASP. A growing body of literature indicates that both senescence and the SASP are sensitive to cellular and organismal metabolic states, which in turn can drive phenotypes associated with metabolic dysfunction. Here, we review the current literature linking senescence and metabolism, with an eye toward findings at the cellular level, including both metabolic inducers of senescence and alterations in cellular metabolism associated with senescence. Additionally, we consider how interventions that target either metabolism or senescent cells might influence each other and mitigate some of the pro-aging effects of cellular senescence. We conclude that the most effective interventions will likely break a degenerative feedback cycle by which cellular senescence promotes metabolic diseases, which in turn promote senescence.

Betamethasone as a potential treatment for preterm birth associated with sterile intra-amniotic inflammation: a murine study

OBJECTIVES

Preterm birth remains the leading cause of perinatal morbidity and mortality worldwide. Preterm birth is preceded by spontaneous preterm labor, which is commonly associated with sterile intra-amniotic inflammation; yet, no approved treatment exists for this clinical condition. Corticosteroids are the standard of care to improve neonatal outcomes in women at risk of preterm birth. Herein, we first validated our model of alarmin-induced preterm birth. Next, we investigated whether treatment with betamethasone could prevent preterm birth resulting from sterile intra-amniotic inflammation in mice.

METHODS

Under ultrasound guidance, the first cohort of dams received an intra-amniotic injection of the alarmin high-mobility group box-1 (HMGB1, n=10) or phosphate-buffered saline (PBS, n=9) as controls. A second cohort of dams received HMGB1 intra-amniotically and were subcutaneously treated with betamethasone (n=15) or vehicle (n=15). Dams were observed until delivery, and perinatal outcomes were observed.

RESULTS

Intra-amniotic HMGB1 reduced gestational length (p=0.04), inducing preterm birth in 40% (4/10) of cases, of which 100% (4/4) were categorized as late preterm births. Importantly, treatment with betamethasone extended the gestational length (p=0.02), thereby reducing the rate of preterm birth by 26.6% (from 33.3% [5/15] to 6.7% [1/15]). Treatment with betamethasone did not worsen the rate of neonatal mortality induced by HMGB1 or alter weight gain in the first three weeks of life.

CONCLUSIONS

Treatment with betamethasone prevents preterm birth induced by the alarmin HMGB1. This study supports the potential utility of betamethasone for treating women with sterile intra-amniotic inflammation.

Pathophysiological Implication of Pattern Recognition Receptors in Fetal Membranes Rupture: RAGE and NLRP Inflammasome

Preterm prelabor ruptures of fetal membranes (pPROM) are a pregnancy complication responsible for 30% of all preterm births. This pathology currently appears more as a consequence of early and uncontrolled process runaway activation, which is usually implicated in the physiologic rupture at term: inflammation. This phenomenon can be septic but also sterile. In this latter case, the inflammation depends on some specific molecules called “alarmins” or “damage-associated molecular patterns” (DAMPs) that are recognized by pattern recognition receptors (PRRs), leading to a microbial-free inflammatory response. Recent data clarify how this activation works and which receptor translates this inflammatory signaling into fetal membranes (FM) to manage a successful rupture after 37 weeks of gestation. In this context, this review focused on two PRRs: the receptor for advanced glycation end-products (RAGE) and the NLRP7 inflammasome.

Tau oligomer induced HMGB1 release contributes to cellular senescence and neuropathology linked to Alzheimer's disease and frontotemporal dementia

Aging, pathological tau oligomers (TauO), and chronic inflammation in the brain play a central role in tauopathies, including Alzheimer's disease (AD) and frontotemporal dementia (FTD). However, the underlying mechanism of TauO-induced aging-related neuroinflammation remains unclear. Here, we show that TauO-associated astrocytes display a senescence-like phenotype in the brains of patients with AD and FTD. TauO exposure triggers astrocyte senescence through high mobility group box 1 (HMGB1) release and inflammatory senescence-associated secretory phenotype (SASP), which mediates paracrine senescence in adjacent cells. HMGB1 release inhibition using ethyl pyruvate (EP) and glycyrrhizic acid (GA) prevents TauO-induced senescence through inhibition of p38-mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB)-the essential signaling pathways for SASP development. Despite the developed tauopathy in 12-month-old hTau mice, EP+GA treatment significantly decreases TauO and senescent cell loads in the brain, reduces neuroinflammation, and thus ameliorates cognitive functions. Collectively, TauO-induced HMGB1 release promotes cellular senescence and neuropathology, which could represent an important common pathomechanism in tauopathies including AD and FTD.

Integrated trajectories of the maternal metabolome, proteome, and immunome predict labor onset

Estimating the time of delivery is of high clinical importance because pre- and postterm deviations are associated with complications for the mother and her offspring. However, current estimations are inaccurate. As pregnancy progresses toward labor, major transitions occur in fetomaternal immune, metabolic, and endocrine systems that culminate in birth. The comprehensive characterization of maternal biology that precedes labor is key to understanding these physiological transitions and identifying predictive biomarkers of delivery. Here, a longitudinal study was conducted in 63 women who went into labor spontaneously. More than 7000 plasma analytes and peripheral immune cell responses were analyzed using untargeted mass spectrometry, aptamer-based proteomic technology, and single-cell mass cytometry in serial blood samples collected during the last 100 days of pregnancy. The high-dimensional dataset was integrated into a multiomic model that predicted the time to spontaneous labor [R = 0.85, 95% confidence interval (CI) [0.79 to 0.89], P = 1.2 × 10^-40, N = 53, training set; R = 0.81, 95% CI [0.61 to 0.91], P = 3.9 × 10^-7, N = 10, independent test set]. Coordinated alterations in maternal metabolome, proteome, and immunome marked a molecular shift from pregnancy maintenance to prelabor biology 2 to 4 weeks before delivery. A surge in steroid hormone metabolites and interleukin-1 receptor type 4 that preceded labor coincided with a switch from immune activation to regulation of inflammatory responses. Our study lays the groundwork for developing blood-based methods for predicting the day of labor, anchored in mechanisms shared in preterm and term pregnancies.

Increased cell-free fetal DNA release after apoptosis and sterile inflammation in human trophoblast cells

PROBLEM

Cell-free fetal DNA (cffDNA) shed from the placenta can be detected in maternal blood and increases incrementally during gestation. Concentrations are further elevated with pregnancy complications. Specific activators of cffDNA release in such complications have not been identified. Here, we use trophoblast cells from early and term placenta to examine cffDNA release following apoptosis, infection, and sterile inflammatory stress.

METHOD OF STUDY

HTR8/SVneo cells were used to model first-trimester trophoblasts, and term cytotrophoblasts (CTBs) were isolated from placentae collected after uncomplicated deliveries. Trophoblasts were treated with varying concentrations of doxorubicin (DOX), lipopolysaccharide (LPS), or high-mobility group box protein 1 (HMGB1) for 18 h. Cells or supernatants were quantified for caspase-3/7 cleavage, pro-inflammatory cytokine secretion, and cffDNA release.

RESULTS

Both HTR8/SVneo and CTBs underwent caspase-3/7 cleavage following DOX treatment, with HTR8/SVneo cells more sensitive to apoptosis than term CTBs. Apoptotic cells released more cffDNA in a dose-dependent manner. Treatment with LPS resulted in an increase in pro-inflammatory IL-6 release, particularly in term CTBs compared to early trophoblasts; however, LPS did not affect cffDNA release. Lastly, while neither cell released more TNF-α following stimulation with HMGB1, both HTR8/SVneo and CTBs released significantly more cffDNA in the presence of HMGB1.

CONCLUSIONS

These data show that apoptosis and sterile inflammation induced by DOX and HMGB1, respectively, cause an increase in cffDNA concentrations in both first-trimester and term trophoblasts. Understanding physiologic release of cffDNA during healthy and complicated pregnancy can identify new targets for the diagnosis and treatment of gestational complications.

Landscape of Preterm Birth Therapeutics and a Path Forward

Preterm birth (PTB) remains the leading cause of infant morbidity and mortality. Despite 50 years of research, therapeutic options are limited and many lack clear efficacy. Tocolytic agents are drugs that briefly delay PTB, typically to allow antenatal corticosteroid administration for accelerating fetal lung maturity or to transfer patients to high-level care facilities. Globally, there is an unmet need for better tocolytic agents, particularly in low- and middle-income countries. Although most tocolytics, such as betamimetics and indomethacin, suppress downstream mediators of the parturition pathway, newer therapeutics are being designed to selectively target inflammatory checkpoints with the goal of providing broader and more effective tocolysis. However, the relatively small market for new PTB therapeutics and formidable regulatory hurdles have led to minimal pharmaceutical interest and a stagnant drug pipeline. In this review, we present the current landscape of PTB therapeutics, assessing the history of drug development, mechanisms of action, adverse effects, and the updated literature on drug efficacy. We also review the regulatory hurdles and other obstacles impairing novel tocolytic development. Ultimately, we present possible steps to expedite drug development and meet the growing need for effective preterm birth therapeutics.

Oxidative Stress Induced Damage and Early Senescence in Preterm Placenta

Introduction

Senescent cells have been demonstrated to release High Mobility Group Box 1 (HMGB1) which induces labor through an inflammatory pathway. This research is aimed at demonstrating whether telomere shortening, proinflammatory HMGB1, and oxidative damage marker 8-OHdG play a role in the placenta of preterm birth in comparison to term birth.

Method

A cross-sectional study on 67 full thickness of the placenta obtained from mothers with term and preterm birth. Mothers with clinical signs of infection (fever > 38°C, leukocytosis > 18000/μL, or abnormal vaginal discharge) and other pregnancy complications were excluded. Real-time polymerase chain reaction was performed to measure T/S ratio and ELISA quantification to measure the amount of HMGB1 and 8-OHdG.

Result

A total of 34 placentas from preterm and 33 placentas from term birth were examined. Maternal characteristics were comparable between the two groups. There were no statistical difference of T/S ratio (p = 0.181), HMGB1 (p = 0.119), and 8-OHdG (p = 0.144) between the preterm and term groups. HMGB1 was moderately correlated with 8-OHdG (r = 0.314). Telomere T/S ratio of the placenta did not differ between preterm and term labor despite difference in gestational age, suggesting earlier shortening in the preterm group. It is possible that critical telomere length has been achieved in both term and preterm placenta that warrants labor through senescence process. The result of our study also showed that HMGB1 was not correlated to telomere length, due to the fact that HMGB1 is not upregulated until the critical length of telomere for senescence is exhibited.

Conclusion

Similar telomere length might be exhibited due to early telomere shortening in preterm birth that mimics the term placenta. The relationship between placental telomere shortening and HMGB1 release remains to be uncovered. Further research is needed to discover the factors leading to early telomere shortening in the placenta of preterm birth.

Oxylipin biosynthesis reinforces cellular senescence and allows detection of senolysis

Cellular senescence is a stress or damage response that causes a permanent proliferative arrest and secretion of numerous factors with potent biological activities. This senescence-associated secretory phenotype (SASP) has been characterized largely for secreted proteins that participate in embryogenesis, wound healing, inflammation, and many age-related pathologies. By contrast, lipid components of the SASP are understudied. We show that senescent cells activate the biosynthesis of several oxylipins that promote segments of the SASP and reinforce the proliferative arrest. Notably, senescent cells synthesize and accumulate an unstudied intracellular prostaglandin, 1a,1b-dihomo-15-deoxy-delta-12,14-prostaglandin J2. Released 15-deoxy-delta-12,14-prostaglandin J2 is a biomarker of senolysis in culture and in vivo. This and other prostaglandin D2-related lipids promote the senescence arrest and SASP by activating RAS signaling. These data identify an important aspect of cellular senescence and a method to detect senolysis.

Extracellular vesicle mediated feto-maternal HMGB1 signaling induces preterm birth

Preterm birth (PTB; <37 weeks of gestation) impacts ∼11% of all pregnancies and contributes to 1 million neonatal deaths worldwide annually. An understanding of the feto-maternal (F-M) signals that initiate birthing (parturition) at term is critical to design strategies to prevent their premature activation, resulting in PTB. Although endocrine and immune cell signaling are well-reported, fetal-derived paracrine signals capable of transitioning quiescent uterus to an active state of labor are poorly studied. Recent reports have suggested that senescence of the fetal amnion membrane coinciding with fetal growth and maturation generates inflammatory signals capable of triggering parturition. This is by increasing the inflammatory load at the feto-maternal interface (FMi) tissues (i.e., amniochorion-decidua). High mobility group box 1 protein (HMGB1), an alarmin, is one of the inflammatory signals released by senescent amnion cells via extracellular vesicles (exosomes; 40-160 nm). Increased levels of HMGB1 in the amniotic fluid, cord and maternal blood are associated with term and PTB. This study tested the hypothesis that senescent amnion cells release HMGB1, which is fetal signaling capable of increasing FMi inflammation, predisposing them to parturition. To test this hypothesis, exosomes from amnion epithelial cells (AECs) grown under normal conditions were engineered to contain HMGB1 by electroporation (eHMGB1). eHMGB1 was characterized (quantity, size, shape, markers and loading efficiency), and its propagation through FMi was tested using a four-chamber microfluidic organ-on-a-chip device (FMi-OOC) that contained four distinct cell types (amnion and chorion mesenchymal, chorion trophoblast and decidual cells) connected through microchannels. eHMGB1 propagated through the fetal cells and matrix to the maternal decidua and increased inflammation (receptor expression [RAGE and TLR4] and cytokines). Furthermore, intra-amniotic injection of eHMGB1 (containing 10 ng) into pregnant CD-1 mice on embryonic day 17 led to PTB. Injecting carboxyfluorescein succinimidyl ester (CFSE)-labeled eHMGB1, we determined in vivo kinetics and report that eHMGB1 trafficking resulting in PTB was associated with increased FMi inflammation. This study determined that fetal exosome mediated paracrine signaling can generate inflammation and induce parturition. Besides, in vivo functional validation of FMi-OOC experiments strengthens the reliability of such devices to test physiologic and pathologic systems.

Molecular Pathways of Cellular Senescence and Placental Aging in Late Fetal Growth Restriction and Stillbirth

Abnormally accelerated, premature placental senescence plays a crucial role in the genesis of pregnancy pathologies. Abnormal growth in the third trimester can present as small for gestational age fetuses or fetal growth restriction. One differs from the other by the presence of signs of placental insufficiency and the risk of stillbirth. The majority of stillbirths occur in normally grown fetuses and are classified as "unexplained", which often leads to conclusions that they were unpreventable. The main characteristic of aging is a gradual decline in the function of cells, tissues, and organs. These changes result in the accumulation of senescent cells in mitotic tissues. These cells begin the aging process that disrupts tissues' normal functions by affecting neighboring cells, degrading the extracellular matrix, and reducing tissues' regeneration capacity. Different degrees of abnormal placentation result in the severity of fetal growth restriction and its sequelae, including fetal death. This review aims to present the current knowledge and identify future research directions to understand better placental aging in late fetal growth restriction and unexplained stillbirth. We hypothesized that the final diagnosis of placental insufficiency can be made only using markers of placental senescence.

Cellular Senescence and the Senescence-Associated Secretory Phenotype as Drivers of Skin Photoaging

Chronic exposure to UVR is known to disrupt tissue homeostasis, accelerate the onset of age-related phenotypes, and increase the risk for skin cancer-a phenomenon defined as photoaging. In this paper, we review the current knowledge on how UV exposure causes cells to prematurely enter cellular senescence. We describe the mechanisms contributing to the accumulation of senescent cells in the skin and how the persistence of cellular senescence can promote impaired regenerative capacity, chronic inflammation, and tumorigenesis associated with photoaging. We conclude by highlighting the potential of senolytic drugs in delaying the onset and progression of age-associated phenotypes in the skin.

Senolytic drugs: from discovery to translation

Senolytics are a class of drugs that selectively clear senescent cells (SC). The first senolytic drugs Dasatinib, Quercetin, Fisetin and Navitoclax were discovered using a hypothesis-driven approach. SC accumulate with ageing and at causal sites of multiple chronic disorders, including diseases accounting for the bulk of morbidity, mortality and health expenditures. The most deleterious SC are resistant to apoptosis and have up-regulation of anti-apoptotic pathways which defend SC against their own inflammatory senescence-associated secretory phenotype (SASP), allowing them to survive, despite killing neighbouring cells. Senolytics transiently disable these SCAPs, causing apoptosis of those SC with a tissue-destructive SASP. Because SC take weeks to reaccumulate, senolytics can be administered intermittently - a 'hit-and-run' approach. In preclinical models, senolytics delay, prevent or alleviate frailty, cancers and cardiovascular, neuropsychiatric, liver, kidney, musculoskeletal, lung, eye, haematological, metabolic and skin disorders as well as complications of organ transplantation, radiation and cancer treatment. As anticipated for agents targeting the fundamental ageing mechanisms that are 'root cause' contributors to multiple disorders, potential uses of senolytics are protean, potentially alleviating over 40 conditions in preclinical studies, opening a new route for treating age-related dysfunction and diseases. Early pilot trials of senolytics suggest they decrease senescent cells, reduce inflammation and alleviate frailty in humans. Clinical trials for diabetes, idiopathic pulmonary fibrosis, Alzheimer's disease, COVID-19, osteoarthritis, osteoporosis, eye diseases and bone marrow transplant and childhood cancer survivors are underway or beginning. Until such studies are done, it is too early for senolytics to be used outside of clinical trials.

Extracellular vesicles in spontaneous preterm birth

Feto-maternal communication helps to maintain pregnancy and contributes to parturition at term and preterm. Endocrine and immune factor are well-reported communication mediators. Recent advances in extracellular vesicle (EV) biology have introduced them as major communication channels between the mother and fetus. EVs are round structures with a lipid bilayer membrane. EVs are generally categorized based on their size and mode of biogenesis. The most commonly reported EVs are exosomes with a size range of 30-160 nm that are formed inside the intraluminal vesicles of multivesicular body. Microvesicles (MVs) are larger than > 200 nm and formed by outward budding of plasma membrane. Vesicles are released from all cells and carry various factors that reflect the physiologic state of cell at the time of their release. Analysis of vesicle provides a snapshot of origin cell. Recent studies in perinatal medicine have shown that exosomes are key communicators between feto-maternal units, and they can cross placenta. Fetal-derived exosomes released under term labor-associated conditions can cause parturition-associated changes in maternal uterine tissues. Exosomes carrying inflammatory cargo can cause preterm birth in animal models suggesting their functional role in parturition. A few reports have profiled differences between exosome cargos from term and preterm pregnancies and indicated their biomarker potential to predict high-risk pregnancy status. There are hardly any reports on MVs and their functional roles in reproduction. Herein, we review of EVs and MVs, their characteristics, function, and usefulness predicting adverse pregnancy complications such as preterm birth.