The decidua-the maternal bed embracing the embryo-maintains the pregnancy

Metabolic reprogramming and heterogeneity during the decidualization process of endometrial stromal cells

The human endometrial decidualization is a transformative event in the pregnant uterus that involves the differentiation of stromal cells into decidual cells. While crucial to the establishment of a successful pregnancy, the metabolic characteristics of decidual cells in vivo remain largely unexplored. Here, we integrated the single-cell RNA sequencing (scRNA-seq) datasets on the endometrium of the menstrual cycle and the maternal-fetal interface in the first trimester to comprehensively decrypt the metabolic characteristics of stromal fibroblast cells. Our results revealed that the differentiation of stromal cells into decidual cells is accompanied by increased amino acid and sphingolipid metabolism. Furthermore, metabolic heterogeneity exists in decidual cells with differentiation maturity disparities. Decidual cells with high metabolism exhibit higher cellular activity and show a strong propensity for signaling. In addition, significant metabolic reprogramming in amino acids and lipids also occurs during the transition from non-pregnancy to pregnancy in the uteri of pigs, cattle, and mice. Our analysis provides comprehensive insights into the dynamic landscape of stromal fibroblast cell metabolism, contributing to our understanding of the metabolism at the molecular dynamics underlying the decidualization process in the human endometrium.

Modeling normal mouse uterine contraction and placental perfusion with non-invasive longitudinal dynamic contrast enhancement MRI

BACKGROUND

The placenta is a transient organ critical for fetal development. Disruptions of normal placental functions can impact health throughout an individual's entire life. Although being recognized by the NIH Human Placenta Project as an important organ, the placenta remains understudied, partly because of a lack of non-invasive tools for longitudinally evaluation for key aspects of placental functionalities.

OBJECTIVE

Our goal is to create a non-invasive preclinical imaging pipeline that can longitudinally probe murine placental health in vivo. We use advanced imaging processing schemes to establish functional biomarkers for non-invasive longitudinal evaluation of placental development.

METHODOLOGY

We implement dynamic contrast enhancement magnetic resonance imaging (DCE-MRI) and analysis pipeline to quantify uterine contraction and placental perfusion dynamics. We use optic flow and time-frequency analysis to quantify and characterize contraction-related placental motion. Our novel imaging and analysis pipeline uses subcutaneous administration of gadolinium for steepest slope-based perfusion evaluation, enabling non-invasive longitudinal monitoring.

RESULTS

We demonstrate that the placenta exhibits spatially asymmetric contractile motion that develops from E14.5 to E17.5. Additionally, we see that placental perfusion, perfusion delivery rate, and substrate delivery all increase from E14.5 to E17.5, with the High Perfusion Chamber (HPC) leading the placental changes that occur from E14.5 to E17.5.

DISCUSSION

We advance the placental perfusion chamber paradigm with a novel, physiologically based threshold model for chamber localization and demonstrate spatially varying placental chambers using multiple functional metrics that assess mouse placental development and remodeling throughout gestation.

CONCLUSION

Our pipeline enables the non-invasive, longitudinal assessment of multiple placenta functions from a single imaging session. Our pipeline serves as a key toolbox for advancing research in mouse models of placental disease and disorder.

Comparative proteomics analysis of decidua reveals altered RNA processing and impaired ribosome function in recurrent pregnancy loss

INTRODUCTION

Factors contributing to recurrent pregnancy loss (RPL) in more than half of the cases are still unknown. The incidence and societal impact of this condition requires urgent elucidation of the mechanisms behind it, which could aid in significant improvement of clinical management.

MATERIALS AND METHODS

Using a highly efficient in-solution digestion method and label-free data-independent LC-MS/MS acquisition with ion mobility, we performed comparative proteomics analysis of the decidua tissues from 19 RPL patients and 10 controls. Differentially abundant proteins (DAPs) were compared and correlated with 3 publicly available transcriptomic datasets and the expression of selected biomarkers was tested by qPCR in decidua and chorionic villi from an extended cohort.

RESULTS

From 1952 proteins identified based on ≥2 peptides, the statistically significant difference in abundance (Anova p ≤ 0.05) and fold change ≥1.2 showed 85 proteins. Pathway analysis using Reactome, KEGG and Wiki pathways identified enrichment of "Signaling by ROBO receptors", "RNA degradation" and "Cytoplasmic Ribosomal Proteins". The correlation between protein and gene expression in decidua revealed that the down-regulated ribosomal proteins in our dataset (RPS15, RPS17, RPL27A, RPL35A and RPL18) showed the same regulation trend at the mRNA level, which was later confirmed for transcripts of RPS15 and RPL18 in our cohort.

DISCUSSION

Our data suggests that the potential causes of RPL from the maternal side could be associated with impaired RNA processing machinery. Furthermore, the list of DAPs in RPL opens future investigations in terms of screening novel gene variants predisposing to pregnancy failure and developing biomarkers for RPL risk.

Apoptotic and non-apoptotic roles of caspases in placenta physiology and pathology

Caspases, a family of cysteine proteases, are pivotal regulators of apoptosis, the tightly controlled cell death process crucial for eliminating excessive or unnecessary cells during development, including placental development. Collecting research has unveiled the multifaceted roles of caspases in the placenta, extending beyond apoptosis. Apart from their involvement in placental tissue remodeling via apoptosis, caspases actively participate in essential regulatory processes, such as trophoblast fusion and differentiation, significantly influencing placental growth and functionality. In addition, growing evidence indicates an elevation in caspase activity under pathological conditions like pre-eclampsia (PE) and intrauterine growth restriction (IUGR), leading to excessive cell death as well as inflammation. Drawing from advancements in caspase research and placental development under both normal and abnormal conditions, we examine the significance of caspases in both cell death (apoptosis) and non-cell death-related processes within the placenta. We also discuss potential therapeutics targeting caspase-related pathways for placenta disorders.

The microbiome in recurrent pregnancy loss - A scoping review

Recurrent pregnancy loss (RPL) is a troubling condition that affects couples worldwide. Despite extensive research efforts, many RPL cases remain unexplained, highlighting the need for novel approaches to unravel its underlying mechanisms. Recent advances in microbiome research have shed light on the potential role of the microbiome in reproductive health and outcomes. Based on a systematic literature research, this review aims to comprehensively explore the current understanding of the microbiome's involvement in RPL, focusing on the vaginal, endometrial, and gut microbiomes. Evidence from the available studies is examined to explain the relationship between the microbiome and RPL. Furthermore, we discuss the diagnostic potential of the microbiome, therapeutic interventions, and future directions in microbiome research for RPL. Understanding the complex interactions between the microbiome and reproductive health holds promise for developing targeted interventions to help patients today diagnosed as unexplained.

Renalase Levels are Decreased in Maternal Blood and Placental Tissues in Pregnancies Associated with Preterm Preeclampsia

Preeclampsia (PEC) is a complication of pregnancy associated with hypertension and the risk of eclampsia. The pathophysiology of PEC is unknown and identifying factors associated with PEC during pregnancy is crucial for placental, fetal, and maternal health. Renalase (RNLS) is an anti-inflammatory secretory flavoprotein associated with hypertension. Recent data demonstrated a correlation between maternal serum RNLS and PEC, and work from our group identified RNLS expression in the placenta. However, it remains unknown whether RNLS levels in placenta are altered by preeclampsia. Additionally, it is unclear if there is a differential effect of preterm and term PEC on RNLS. We demonstrate that serum RNLS was reduced in preterm cases of PEC. Similarly, placental RNLS was diminished in the chorion of preterm cases of PEC. However, a reduction of RNLS in the decidua was observed with all cases of PEC, while the levels of RNLS within the placental villi were similar in all cases. Overall, we demonstrate that RNLS correlates with PEC both systemically in maternal serum and locally within the placenta, with variable effects on the different layers of the placenta and more pronounced in preterm cases.

FANCA facilitates G1/S cell cycle advancement, proliferation, migration and invasion in gastric cancer

The present study explores the function of FANCA gene, a pivotal member of the Fanconi anaemia (FA) pathway crucial for preserving genomic stability and preventing cancer, particularly in the context of gastric cancer (GC). Using immunohistochemistry, quantitative real-time PCR, and western blot analysis, we evaluate FANCA mRNA and protein expressions in GC cell lines. The relationship between FANCA expression and clinicopathological characteristics is also explored. Various assays, including CCK8, colony formation, wound healing, and Transwell assays, are used to assess functional changes in cells associated with FANCA. Flow cytometry is utilized to evaluate alterations in the cell cycle resulted from FANCA knockdown and overexpression. Our findings show elevated FANCA expression in GC cell lines, with levels correlated with pathologic stage and lymphatic metastasis. FANCA knockdown impedes cell proliferation, migration, and invasion and induces G1/S phase cell cycle arrest. Conversely, FANCA overexpression stimulates cell proliferation, migration, and invasion. In vivo xenograft experiments confirm the promotional role of FANCA in GC tumor progression. Moreover, FANCA overexpression is associated with the activation of cell cycle. Collectively, our results suggest that FANCA drives malignant cell behaviors in GC through the cell cycle pathway, highlighting its potential as a therapeutic target for the treatment of GC.

Estrogen and Progesterone Receptors Are Dysregulated at the BPH/5 Mouse Preeclamptic-Like Maternal-Fetal Interface

The etiopathogenesis of preeclampsia, a leading hypertensive disorder of pregnancy, has been proposed to involve an abnormal circulating sex hormone profile and misexpression of placental estrogen and progesterone receptors (ER and PR, respectively). However, existing research is vastly confined to third trimester preeclamptic placentas. Consequently, the placental-uterine molecular crosstalk and the dynamic ER and PR expression pattern in the peri-conception period remain overlooked. Herein, our goal was to use the BPH/5 mouse to elucidate pre-pregnancy and early gestation Er and Pr dynamics in a preeclamptic-like uterus. BPH/5 females display low circulating estrogen concentration during proestrus, followed by early gestation hypoestrogenemia, hyperprogesteronemia, and a spontaneous preeclamptic-like phenotype. Preceding pregnancy, the gene encoding Er alpha (Erα, Esr1) is upregulated in the diestrual BPH/5 uterus. At the peak of decidualization, Esr1, Er beta (Erβ, Esr2), and Pr isoform B (Pr-B) were upregulated in the BPH/5 maternal-fetal interface. At the protein level, BPH/5 females display higher percentage of decidual cells with nuclear Erα expression, as well as Pr downregulation in the decidua, luminal and glandular epithelium. In conclusion, we provide evidence of disrupted sex hormone signaling in the peri-conception period of preeclamptic-like pregnancies, potentially shedding some light onto the intricate role of sex hormone signaling at unexplored timepoints of human preeclampsia.

Lipid nanoparticle structure and delivery route during pregnancy dictate mRNA potency, immunogenicity, and maternal and fetal outcomes

Treating pregnancy-related disorders is exceptionally challenging because the threat of maternal and/or fetal toxicity discourages the use of existing medications and hinders new drug development. One potential solution is the use of lipid nanoparticle (LNP) RNA therapies, given their proven efficacy, tolerability, and lack of fetal accumulation. Here, we describe LNPs for efficacious mRNA delivery to maternal organs in pregnant mice via several routes of administration. In the placenta, our lead LNP transfected trophoblasts, endothelial cells, and immune cells, with efficacy being structurally dependent on the ionizable lipid polyamine headgroup. Next, we show that LNP-induced maternal inflammatory responses affect mRNA expression in the maternal compartment and hinder neonatal development. Specifically, pro-inflammatory LNP structures and routes of administration curtailed efficacy in maternal lymphoid organs in an IL-1β-dependent manner. Further, immunogenic LNPs provoked the infiltration of adaptive immune cells into the placenta and restricted pup growth after birth. Together, our results provide mechanism-based structural guidance on the design of potent LNPs for safe use during pregnancy.

Roles of bone morphogenetic proteins in endometrial remodeling during the human menstrual cycle and pregnancy

BACKGROUND

During the human menstrual cycle and pregnancy, the endometrium undergoes a series of dynamic remodeling processes to adapt to physiological changes. Insufficient endometrial remodeling, characterized by inadequate endometrial proliferation, decidualization and spiral artery remodeling, is associated with infertility, endometriosis, dysfunctional uterine bleeding, and pregnancy-related complications such as preeclampsia and miscarriage. Bone morphogenetic proteins (BMPs), a subset of the transforming growth factor-β (TGF-β) superfamily, are multifunctional cytokines that regulate diverse cellular activities, such as differentiation, proliferation, apoptosis, and extracellular matrix synthesis, are now understood as integral to multiple reproductive processes in women. Investigations using human biological samples have shown that BMPs are essential for regulating human endometrial remodeling processes, including endometrial proliferation and decidualization.

OBJECTIVE AND RATIONALE

This review summarizes our current knowledge on the known pathophysiological roles of BMPs and their underlying molecular mechanisms in regulating human endometrial proliferation and decidualization, with the goal of promoting the development of innovative strategies for diagnosing, treating and preventing infertility and adverse pregnancy complications associated with dysregulated human endometrial remodeling.

SEARCH METHODS

A literature search for original articles published up to June 2023 was conducted in the PubMed, MEDLINE, and Google Scholar databases, identifying studies on the roles of BMPs in endometrial remodeling during the human menstrual cycle and pregnancy. Articles identified were restricted to English language full-text papers.

OUTCOMES

BMP ligands and receptors and their transduction molecules are expressed in the endometrium and at the maternal-fetal interface. Along with emerging technologies such as tissue microarrays, 3D organoid cultures and advanced single-cell transcriptomics, and given the clinical availability of recombinant human proteins and ongoing pharmaceutical development, it is now clear that BMPs exert multiple roles in regulating human endometrial remodeling and that these biomolecules (and their receptors) can be targeted for diagnostic and therapeutic purposes. Moreover, dysregulation of these ligands, their receptors, or signaling determinants can impact endometrial remodeling, contributing to infertility or pregnancy-related complications (e.g. preeclampsia and miscarriage).

WIDER IMPLICATIONS

Although further clinical trials are needed, recent advancements in the development of recombinant BMP ligands, synthetic BMP inhibitors, receptor antagonists, BMP ligand sequestration tools, and gene therapies have underscored the BMPs as candidate diagnostic biomarkers and positioned the BMP signaling pathway as a promising therapeutic target for addressing infertility and pregnancy complications related to dysregulated human endometrial remodeling.

CD24+ decidual stromal cells: a novel heterogeneous population with impaired regulatory T cell induction and potential association with recurrent miscarriage

OBJECTIVE

To explore the heterogeneity of CD24+ decidual stromal cells (DSCs) in patients with recurrent miscarriages (RMs).

DESIGN

We have discerned that the expression of CD24 serves to differentiate two stable and functionally distinct lineages of DSCs. The heterogeneity of CD24+ DSCs has been scrutinized, encompassing variances in stromal markers, transcriptional profiles, metabolic activity, and immune regulation.

SETTING

Department of Reproductive Immunology, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University; Shanghai Institute of Immunity and Infection, Chinese Academy of Science.

PATIENTS

A total of 129 early decidual samples were obtained, comprising 36 from healthy donors and 93 from patients with RMs. Blood samples were collected before the surgical procedure. Paraffin-embedded segments from 20 decidual samples of patients with RMs were obtained.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

The flow cytometry was used to quantify the expression of CD24+ DSCs in both healthy donors and patients with RMs, although it also evaluated the cellular heterogeneity. To ascertain the transcriptomic profiles of CD24+ DSCs by reanalyzing our single-cell transcriptomic data. Additionally, to measure the metabolomic activity of CD24+ DSCs from patients with RMs, ultraperformance liquid chromatography-mass spectrometry was employed. Through the implementation of a coculture system, we unraveled the role of CD24+ DSCs in immune regulation.

RESULTS

Patients with RMs exhibit a notable enrichment of CD24+ DSCs, revealing a pronounced heterogeneity characterized by variations in stromal markers and transcriptional profiles. The heightened enrichment of CD24+ DSCs may play a pivotal role in triggering decidual inflammation and dysfunction in decidualization. Furthermore, CD24+ DSCs showed diverse metabolic activities and impeded the induction of naïve CD4+ T cells into regulatory T cells through the abundant secretion of 3-hydroxyisovaleric acid. Finally, our investigations have revealed that intraperitoneal administration of 3-hydroxyisovaleric acid in mouse models can elevate the risk of RM.

CONCLUSION

We have successfully identified a disease-associated subset of CD24+ decidual stromal cells that could potentially contribute to the development of RM through the impairment of decidual immune tolerance. Targeting these specific CD24+ DSCs might hold promising prospects for therapeutic interventions in the clinical management of RM.

Modulation of cell-mediated immunity during pregnancy in wild bonobos

During pregnancy, the mammalian immune system must simultaneously protect against pathogens while being accommodating to the foreign fetal tissues. Our current understanding of this immune modulation derives predominantly from industrialized human populations and laboratory animals. However, their environments differ considerably from the pathogen-rich, resource-scarce environments in which pregnancy and the immune system co-evolved. For a better understanding of immune modulation during pregnancy in challenging environments, we measured urinary neopterin, a biomarker of cell-mediated immune responses, in 10 wild female bonobos (Pan paniscus) before, during and after pregnancy. Bonobos, sharing evolutionary roots and pregnancy characteristics with humans, serve as an ideal model for such investigation. Despite distinct environments, we hypothesized that cell-mediated immune modulation during pregnancy is similar between bonobos and humans. As predicted, neopterin levels were higher during than outside of pregnancy, and highest in the third trimester, with a significant decline post-partum. Our findings suggest shared mechanisms of cell-mediated immune modulation during pregnancy in bonobos and humans that are robust despite distinct environmental conditions. We propose that these patterns indicate shared immunological processes during pregnancy among hominins, and possibly other primates. This finding enhances our understanding of reproductive immunology.

MUC1 promotes RIF by regulating macrophage ROS-SHP2 signaling pathway to up-regulate inflammatory response and inhibit angiogenesis

OBJECTIVE

To explore the effect of MUC1 on recurrent implantation failure (RIF) and its molecular mechanism.

METHODS

Bioinformation analysis was used to find possible molecular mechanisms of specific genes in the pathogenesis of RIF. The number of M1 and M2 macrophages was measured by flow cytometry. Immunohistochemical staining and western blotting were used to detect the expression of related proteins. Angiogenesis capacity was measured by cell tube-formation assay.

RESULTS

Bioinformatics analysis results suggest that MUC1 may play an important role in RIF. The results of flow cytometry showed that compared with NC group, M1 macrophages increased significantly and M2 macrophages decreased significantly in MUC1 OE group. The results of immunohistochemical staining showed that MUC1 could inhibit the expression of VEGF. Western blotting results showed that MUC1 could significantly increase the expression of P22, P47, gp91, p-TBK1, IFNγ and IL-1β, and decrease the expression of p-SHP2, p-PI3K, p-mTOR, HIF1α and VEGF. After the addition of ROS inhibitor and PI3K inhibitor, the effect of MUC1 on the above proteins was eliminated. The results of tube formation experiments showed that MUC1 could inhibit vascular formation.

CONCLUSION

As a promising biomarker for the diagnosis of RIF, MUC1 can promote RIF by regulating macrophage ROS-SHP2 signaling pathway to up-regulate inflammatory response and inhibit angiogenesis.

Modeling Normal Mouse Uterine Contraction and Placental Perfusion with Non-invasive Longitudinal Dynamic Contrast Enhancement MRI

The placenta is a transient organ critical for fetal development. Disruptions of normal placental functions can impact health throughout an individual's entire life. Although being recognized by the NIH Human Placenta Project as an important organ, the placenta remains understudied, partly because of a lack of non-invasive tools for longitudinally evaluation for key aspects of placental functionalities. Non-invasive imaging that can longitudinally probe murine placental health in vivo are critical to understanding placental development throughout pregnancy. We developed advanced imaging processing schemes to establish functional biomarkers for non-invasive longitudinal evaluation of placental development. We developed a dynamic contrast enhancement magnetic resonance imaging (DCE-MRI) pipeline combined with advanced image process methods to model uterine contraction and placental perfusion dynamics. Our novel imaging pipeline uses subcutaneous administration of gadolinium for steepest-slope based perfusion evaluation. This enables non-invasive longitudinal monitoring. Additionally, we advance the placental perfusion chamber paradigm with a novel physiologically-based threshold model for chamber localization and demonstrate spatially varying placental chambers using multiple functional metrics that assess mouse placental development and continuing remodeling throughout gestation. Lastly, using optic flow to quantify placental motions arisen from uterine contractions in conjunction with time-frequency analysis, we demonstrated that the placenta exhibited asymmetric contractile motion.

PLCD3 inhibits apoptosis and promotes proliferation, invasion and migration in gastric cancer

Gastric cancer (GC) is a heterogeneous disease whose development is accompanied by alterations in a variety of pathogenic genes. The phospholipase C Delta 3 enzyme is a member of the phospholipase C family, which controls substance transport between cells in the body. However, its role in gastric cancer has not been discovered. The purpose of this study was to investigate the expression and mechanism of action of PLCD3 in connection to gastric cancer. By Western blot analysis and immunohistochemistry, PLCD3 mRNA and protein expression levels were measured, with high PLCD3 expression suggesting poor prognosis. In N87 and HGC-27 cells, the silencing of PLCD3 using small interfering RNA effectively induced apoptosis and inhibited tumor cell proliferation, invasion, and migration. Conversely, overexpression of PLCD3 using overexpressed plasmids inhibited apoptosis in AGS and BGC-823 cells and promoted proliferation, migration, and invasion. In order to investigate the underlying mechanisms, we conducted further analysis of PLCD3, which indicates that this protein is closely related to the cell cycle and EMT. Additionally, we found that overexpression of PLCD3 inhibits apoptosis and promotes the development of GC cells through JAK2/STAT3 signaling. In conclusion, PLCD3 inhibits apoptosis and promotes proliferation, invasion, and migration, which indicated that PLCD3 might serve as a therapeutic target for gastric cancer.

Kisspeptin prevents pregnancy loss by modulating the immune microenvironment at the maternal-fetal interface in recurrent spontaneous abortion

PROBLEM

Immune factors are crucial in the development of recurrent spontaneous abortion (RSA). This study aimed to investigate whether kisspeptin regulates immune cells at the maternal-fetal interface and whether G protein-coupled receptor 54 (GPR54) is involved in this process, through which it contributes to the pathogenesis of RSA.

METHOD OF STUDY

Normal pregnancy (NP) (CBA/J × BALB/c) and RSA (CBA/J × DBA/2) mouse models were established. NP mice received tail vein injections of PBS and KP234 (blocker of kisspeptin receptor), whereas RSA mice received PBS and KP10 (active fragment of kisspeptin). The changes in immune cells in mouse spleen and uterus were assessed using flow cytometry and immunofluorescence. The expression of critical cytokines was examined by flow cytometry, ELISA, Western blotting, and qPCR. Immunofluorescence was employed to detect the coexpression of FOXP3 and GPR54.

RESULTS

The findings revealed that the proportion of Treg cells, MDSCs, and M2 macrophages in RSA mice was lower than that in NP mice, but it increased following the tail vein injection of KP10. Conversely, the proportion of these cells was reduced in NP mice after the injection of KP234. However, the trend of γδT cell proportion change is contrary to these cells. Furthermore, FOXP3 and GPR54 were coexpressed in mouse spleen and uterus Treg cells as well as in the human decidua samples.

CONCLUSION

Our results suggest that kisspeptin potentially participates in the pathogenesis of RSA by influencing immune cell subsets at the maternal-fetal interface, including Treg cells, MDSC cells, γδT cells, and M2 macrophages.

The use of immunomodulation therapy in women with recurrent implantation failure undergoing assisted conception: A multicentre cohort study

PROBLEM

Recurrent implantation failure (RIF) after multiple embryo transfers remains a vexing problem and immunomodulators have been used with conflicting results. This study aims to assess the effect of immunomodulation therapy on live birth rate (LBR) in women with RIF undergoing assisted reproduction treatment (ART).

METHOD OF STUDY DESIGN

This is a retrospective cohort study in multicentre network of private assisted conception units in the UK. The study included women who had at least two failed attempts of embryo transfers at CARE fertility network in the period from 1997 to 2018. Women in the treatment group had immunomodulator drugs in the form of corticosteroids, low molecular weight heparin (LMWH), and intravenous intralipid (IVIL) infusions, either separately or in combination, after immunological testing, in addition to standard ART whilst women in the control group had only ART without immunomodulators. The primary outcome was LBR per cycle. Secondary outcomes included the rates of clinical pregnancy (CPR), cumulative live birth (CLBR), and miscarriage.

RESULTS

A total of 27 163 ART cycles fulfilled the inclusion criteria, of which 5083 had immunomodulation treatment in addition to standard ART treatment, and 22 080 had standard ART treatment alone. Women in the treatment group were significantly older (mean age 38.5 vs. 37.1 years, p < .001), and had a higher number of previous failed ART cycles (mean 4.3 vs. 3.8, p < .01). There was a higher LBR in women who received immunomodulation therapy when compared with the control group (20.9% vs. 15.8%, odds ratio [OR] 1.4, 95% confidence interval [CI] 1.29-1.53, p < .001). Multivariate regression analysis showed that immunomodulation treatment was a significant independent predictor of live birth after adjusting for other confounders (adjusted OR [aOR] 1.33, 95% CI 1.15-1.54, p < .001). Survival analysis showed a higher CLBR in the treatment group (adjusted hazard ratio [aHR] 1.78, 95% CI 1.62-1.94, p < .001).

CONCLUSION(S)

This study provides evidence of a potential beneficial effect of immunomodulation therapy in women with RIF after immunological testing. There remains a need for high quality, adequately powered multicentre RCTs to robustly address the role of immunomodulation in women with RIF. There is also an urgent need for standardised screening tests for immune disorders that could preclude implantation.

Melatonin: the placental antioxidant and anti-inflammatory

Melatonin (N-acetyl-5-methoxytryptamine) is an indolamine hormone with many physiological and biological roles. Melatonin is an antioxidant, anti-inflammatory, free radical scavenger, circadian rhythm regulator, and sleep hormone. However, its most popular role is the ability to regulate sleep through the circadian rhythm. Interestingly, recent studies have shown that melatonin is an important and essential hormone during pregnancy, specifically in the placenta. This is primarily due to the placenta's ability to synthesize its own melatonin rather than depending on the pineal gland. During pregnancy, melatonin acts as an antioxidant and anti-inflammatory, which is necessary to ensure a stable environment for both the mother and the fetus. It is an essential antioxidant in the placenta because it reduces oxidative stress by constantly scavenging for free radicals, i.e., maintain the placenta's integrity. In a healthy pregnancy, the maternal immune system is constantly altered to accommodate the needs of the growing fetus, and melatonin acts as a key anti-inflammatory by regulating immune homeostasis during early and late gestation. This literature review aims to identify and summarize melatonin's role as a powerful antioxidant and anti-inflammatory that reduces oxidative stress and inflammation to maintain a favorable homeostatic environment in the placenta throughout gestation.

Deciphering maternal-fetal cross-talk in the human placenta during parturition using single-cell RNA sequencing

Labor is a complex physiological process requiring a well-orchestrated dialogue between the mother and fetus. However, the cellular contributions and communications that facilitate maternal-fetal cross-talk in labor have not been fully elucidated. Here, single-cell RNA sequencing (scRNA-seq) was applied to decipher maternal-fetal signaling in the human placenta during term labor. First, a single-cell atlas of the human placenta was established, demonstrating that maternal and fetal cell types underwent changes in transcriptomic activity during labor. Cell types most affected by labor were fetal stromal and maternal decidual cells in the chorioamniotic membranes (CAMs) and maternal and fetal myeloid cells in the placenta. Cell-cell interaction analyses showed that CAM and placental cell types participated in labor-driven maternal and fetal signaling, including the collagen, C-X-C motif ligand (CXCL), tumor necrosis factor (TNF), galectin, and interleukin-6 (IL-6) pathways. Integration of scRNA-seq data with publicly available bulk transcriptomic data showed that placenta-derived scRNA-seq signatures could be monitored in the maternal circulation throughout gestation and in labor. Moreover, comparative analysis revealed that placenta-derived signatures in term labor were mirrored by those in spontaneous preterm labor and birth. Furthermore, we demonstrated that early in gestation, labor-specific, placenta-derived signatures could be detected in the circulation of women destined to undergo spontaneous preterm birth, with either intact or prelabor ruptured membranes. Collectively, our findings provide insight into the maternal-fetal cross-talk of human parturition and suggest that placenta-derived single-cell signatures can aid in the development of noninvasive biomarkers for the prediction of preterm birth.

Licochalcone A induces cell cycle arrest and apoptosis via suppressing MAPK signaling pathway and the expression of FBXO5 in lung squamous cell cancer

Lung squamous cell carcinoma (LSCC) is a highly heterogeneous malignancy with high mortality and few therapeutic options. Licochalcone A (LCA, PubChem ID: 5318998) is a chalcone extracted from licorice and possesses anticancer and anti‑inflammatory activities. The present study aimed to elucidate the anticancer effect of LCA on LSCC and explore the conceivable molecular mechanism. MTT assay revealed that LCA significantly inhibited the proliferation of LSCC cells with less cytotoxicity towards human bronchial epithelial cells. 5‑ethynyl‑2'‑deoxyuridine (EdU) assay demonstrated that LCA could reduce the proliferation rate of LSCC cells. The flow cytometric assays indicated that LCA increased the cell number of the G1 phase and induced the apoptosis of LSCC cells. LCA downregulated the protein expression of cyclin D1, cyclin E, CDK2 and CDK4. Meanwhile, LCA increased the expression level of Bax, cleaved poly(ADP‑ribose)polymerase‑1 (PARP1) and caspase 3, as well as downregulated the level of Bcl‑2. Proteomics assay demonstrated that LCA exerted its antitumor effects via inhibiting mitogen‑activated protein kinase (MAPK) signaling pathways and the expression of F‑box protein 5 (FBXO5). Western blot analysis showed that LCA decreased the expression of p‑ERK1/2, p‑p38MAPK and FBXO5. In the xenograft tumors of LSCC, LCA significantly inhibited the volumes and weight of tumors in nude mice with little toxicity in vital organs. Therefore, the present study demonstrated that LCA effectively inhibited cell proliferation and induced apoptosis in vitro, and suppressed xenograft tumor growth in vivo. LCA may serve as a future therapeutic candidate of LSCC.

Endometrial receptivity in women of advanced age: an underrated factor in infertility

BACKGROUND

Modern lifestyle has led to an increase in the age at conception. Advanced age is one of the critical risk factors for female-related infertility. It is well known that maternal age positively correlates with the deterioration of oocyte quality and chromosomal abnormalities in oocytes and embryos. The effect of age on endometrial function may be an equally important factor influencing implantation rate, pregnancy rate, and overall female fertility. However, there are only a few published studies on this topic, suggesting that this area has been under-explored. Improving our knowledge of endometrial aging from the biological (cellular, molecular, histological) and clinical perspectives would broaden our understanding of the risks of age-related female infertility.

OBJECTIVE AND RATIONALE

The objective of this narrative review is to critically evaluate the existing literature on endometrial aging with a focus on synthesizing the evidence for the impact of endometrial aging on conception and pregnancy success. This would provide insights into existing gaps in the clinical application of research findings and promote the development of treatment options in this field.

SEARCH METHODS

The review was prepared using PubMed (Medline) until February 2023 with the keywords such as 'endometrial aging', 'receptivity', 'decidualization', 'hormone', 'senescence', 'cellular', 'molecular', 'methylation', 'biological age', 'epigenetic', 'oocyte recipient', 'oocyte donation', 'embryo transfer', and 'pregnancy rate'. Articles in a language other than English were excluded.

OUTCOMES

In the aging endometrium, alterations occur at the molecular, cellular, and histological levels suggesting that aging has a negative effect on endometrial biology and may impair endometrial receptivity. Additionally, advanced age influences cellular senescence, which plays an important role during the initial phase of implantation and is a major obstacle in the development of suitable senolytic agents for endometrial aging. Aging is also accountable for chronic conditions associated with inflammaging, which eventually can lead to increased pro-inflammation and tissue fibrosis. Furthermore, advanced age influences epigenetic regulation in the endometrium, thus altering the relation between its epigenetic and chronological age. The studies in oocyte donation cycles to determine the effect of age on endometrial receptivity with respect to the rates of implantation, clinical pregnancy, miscarriage, and live birth have revealed contradictory inferences indicating the need for future research on the mechanisms and corresponding causal effects of women's age on endometrial receptivity.

WIDER IMPLICATIONS

Increasing age can be accountable for female infertility and IVF failures. Based on the complied observations and synthesized conclusions in this review, advanced age has been shown to have a negative impact on endometrial functioning. This information can provide recommendations for future research focusing on molecular mechanisms of age-related cellular senescence, cellular composition, and transcriptomic changes in relation to endometrial aging. Additionally, further prospective research is needed to explore newly emerging therapeutic options, such as the senolytic agents that can target endometrial aging without affecting decidualization. Moreover, clinical trial protocols, focusing on oocyte donation cycles, would be beneficial in understanding the direct clinical implications of endometrial aging on pregnancy outcomes.

Endometrial Glucose Metabolism During Early Pregnancy

Approximately 50% of human pregnancies humans fail, most before or during implantation. One factor contributing to pregnancy loss is abnormal glucose metabolism in the endometrium. Glucose contributes to preimplantation embryo development, uterine receptivity, and attachment of the embryo. Across multiple species, the epithelium stores glucose as the macromolecule glycogen at estrus. This reserve is mobilized during the preimplantation period. Glucose from circulation or glycogenolysis can be secreted into the uterine lumen for use by the embryo or metabolized via glycolysis, producing ATP for the cell. The resulting pyruvate could be converted to lactate, another important nutrient for the embryo. Fructose is an important nutrient for early embryos, and the epithelium and placenta can convert glucose to fructose via the polyol pathway. The epithelium also uses glucose to glycosylate proteins, which regulates embryo attachment. In some species, decidualization of the stroma is critical to successful implantation. Formation of the decidua requires increased glucose metabolism via the pentose phosphate pathway and glycolysis. After decidualization, the cells switch to aerobic glycolysis to produce ATP. Paradoxically, the decidua also stores large amounts of glucose as glycogen. Too little glucose or an inability to take up glucose impairs embryo development and decidualization. Conversely, too much glucose inhibits these same processes. This likely contributes to the reduced pregnancy rates associated with conditions like obesity and diabetes. Collectively, precise control of glucose metabolism is important for several endometrial processes required to establish a successful pregnancy. The factors regulating these metabolic processes remain poorly understood.

Mechanism of BLIMP1/TRIM66/COX2 in human decidua participates in parturition†

The mechanism underlying the initiation of parturition remains unclear. Cyclooxygenase 2 and prostaglandins in decidual membrane tissue play an important role in the "parturition cascade." With the advancement of gestation, the expression of the transcriptional suppressor B lymphocyte-induced maturation protein 1 in the decidual membrane gradually decreases. Through chromatin immunoprecipitation sequencing, we found that B lymphocyte-induced maturation protein 1 has a binding site in the distal intergenic of PTGS2(COX2). Tripartite motif-containing protein 66 is a chromatin-binding protein that usually performs transcriptional regulatory functions by "reading" histone modification sites in chromatin. In this study, tripartite motif-containing protein 66 exhibits the same trend of expression as B lymphocyte-induced maturation protein 1 in the decidua during gestation. Moreover, the co-immunoprecipitation assay revealed that tripartite motif-containing protein 66 combined with B lymphocyte-induced maturation protein 1. This finding indicated that tripartite motif-containing protein 66 formed a transcription complex with B lymphocyte-induced maturation protein 1, which coregulated the expression of COX2. In animal experiments, we injected si-Blimp1 adenoviruses (si-Blimp1), Blimp1 overexpression plasmid (Blimp1-OE), and Trim66 overexpression plasmid (Trim66-OE) through the tail vein of mice. The results showed that B lymphocyte-induced maturation protein 1 and tripartite motif-containing protein 66 affected the initiation of parturition in mice. Therefore, the present evidence suggests that B lymphocyte-induced maturation protein 1 and tripartite motif-containing protein 66 partially participate in the initiation of labor, which may provide a new perspective for exploring the mechanism of term labor.

Novel therapies for graft versus host disease with a focus on cell therapies

Graft versus host disease (GVHD) can occur at any period post allogeneic hematopoietic stem cell transplantation as a common clinical complication contributing to significant morbidity and mortality. Acute GVHD develops in approximately 30-50% of patients receiving transplants from matched related donors. High doses of steroids are used as first-line treatment, but are unsuccessful in around 40% of patients, resulting in the diagnosis of steroid-refractory acute GVHD. Consensus has yet to develop for the management of steroid-refractory acute GVHD, and prognosis at six months has been estimated at around 50%. Thus, it is critical to find effective treatments that increase survival of steroid-refractory acute GVHD. This article describes the currently known characteristics, pathophysiology, and treatments for GVHD, with a special focus on recent advances in cell therapies. In particular, a novel cell therapy using decidua stromal cells (DSCs) was recently shown to have promising results for acute GVHD, with improved effectiveness over previous treatments including mesenchymal stromal cells. At the Karolinska Institute, severe acute GVHD patients treated with placenta-derived DSCs supplemented with either 5% albumin or 10% AB plasma displayed a one-year survival rate of 76% and 47% respectively. Furthermore, patients with steroid-refractory acute GVHD, displayed survival rates of 73% with albumin and 31% with AB plasma-supplemented DSCs, compared to the 20% survival rate in the mesenchymal stromal cell control group. Adverse events and deaths were found to be attributed only to complications of hematopoietic stem cell transplant and GVHD, not to the study intervention. ASC Therapeutics, Inc, in collaboration with the Karolinska Institute, will soon initiate a phase 2 multicenter, open-label study to further assess the efficacy and safety of intravenous DSC treatment in sixty patients with Grade II-IV steroid-refractory acute GVHD. This novel cell therapy represents a promising treatment to combat the poor prognosis that steroid-refractory acute GVHD patients currently face.

Immunoexpression of neuropilin-1 in the chorionic villi of HIV-infected preeclamptic South African women of African ancestry

Neuropilin-1 (NRP-1) is an essential regulator of maternal immune tolerance, placentation, and angiogenesis. Its dysregulation in preeclampsia (PE) and human immunodeficiency virus (HIV) infection implicates NRP-1 in disease susceptibility and progression. Therefore, this study investigates placental NRP-1 immunoexpression in HIV-complicated preeclamptic pregnancies in South African women of African ancestry receiving antiretroviral therapy. Immunohistochemistry of recombinant anti-neuropilin-1 antibody was performed on placental tissue from 30 normotensive and 60 early onset (EOPE) and late-onset (LOPE) preeclamptic women stratified by HIV status. Qualitative analysis of NRP-1 immunostaining within the chorionic villi revealed a predominant localization in trophoblasts and syncytial knots as well as endothelial, fibroblast-like, and Hofbauer cells. Following morphometric evaluation, we report that PE and HIV infection and/or antiretroviral usage independently downregulate placental NRP-1 immunoexpression; however, as a comorbidity, this decline is further augmented within the conducting and exchange villi. Furthermore, reduced immunoexpression of NRP-1 in EOPE compared with LOPE villi may be due to maternal-fetal maladaptation. It is plausible that the decreased NRP-1 immunoexpression in PE placentae facilitates syncytiotrophoblast apoptosis and subsequent deportation of NRP-1 into the maternal circulation, contributing to the anti-angiogenic milieu of PE. We hypothesize that the intense NRP-1 immunoreactivity observed in Hofbauer cells at the maternal-fetal interface may contribute to the natural prevention mechanism of HIV vertical transmission.

Spatiotemporal insight into early pregnancy governed by immune-featured stromal cells

Endometrial decidualization connecting embryo implantation and placentation is transient but essential for successful pregnancy, which, however, is not systematically investigated. Here, we use a scStereo-seq technology to spatially visualize and define the dynamic functional decidual hubs assembled by distinct immune, endothelial, trophoblast, and decidual stromal cells (DSCs) in early pregnant mice. We unravel the DSC transdifferentiation trajectory and surprisingly discover a dual-featured type of immune-featured DSCs (iDSCs). We find that immature DSCs attract immune cells and induce decidual angiogenesis at the mesenchymal-epithelial transition hub during decidualization initiation. iDSCs enable immune cell recruitment and suppression, govern vascularization, and promote cytolysis at immune cell assembling and vascular hubs, respectively, to establish decidual homeostasis at a later stage. Interestingly, dysfunctional and spatially disordered iDSCs cause abnormal accumulation of immune cells in the vascular hub, which disrupts decidual hub specification and eventually leads to pregnancy complications in DBA/2-mated CBA/J mice.

Decidualization dampens toll-like receptor mediated inflammatory responses in human endometrial stromal cells by upregulating IκBα

Endometrial stromal cells (EnSCs) are the major cell type of the human endometrium and they undergo dramatic differentiation, termed decidualization, every month that enables them to be receptive to implantation. Appropriate decidualization and EnSC function is key for a successful pregnancy. EnSC function may be affected when the uterus is exposed to bacterial and viral infection. However, how human EnSCs respond to viral and bacterial components have not been well-studied and it remains unclear whether uterine innate immune responses change during decidualization. This study demonstrated that viral double-stranded RNA [Poly(I:C)] and bacterial lipopolysaccharide (LPS) upregulated undecidualized human EnSC production of a large array of proinflammatory cytokines and chemokines, and revealed that these immune responses were significantly dampened during decidualization in vitro and in vivo. This dampened response was associated with increased NFKBIA transcription during decidualization that leads to the accumulation of this negative regulator in decidualizing EnSCs that can bind to NFκB p65 and prevents its nuclear translocation and downstream Toll-like receptor signaling. These findings highlight that endometrial responses to infection may vary at different stages of the menstrual cycle which may be important for preparing the endometrium to support the growth of the semi-allogenic blastocyst. This work emphasizes the need to consider menstrual cycle stage, sex hormone levels and the differentiation status of cells when examining inflammatory responses in the future.

Dissecting human placental cells heterogeneity in preeclampsia and gestational diabetes using single-cell sequencing

Preeclampsia (PE) and gestational diabetes mellitus (GDM) are pregnancy-specific complications, which affect maternal health and fetal outcomes. Currently, clinical and pathological studies have shown that placenta homeostasis is affected by these two maternal diseases. In this study, we aimed to gain insight into the heterogeneous changes in cell types in placental tissue-isolated from cesarean section by single-cell sequencing, including those patients diagnosed with PE (n = 5), GDM (n = 5) and healthy control (n = 5). A total of 96,048 cells (PE: 31,672; GDM: 25,294; control: 39,082) were identified in six cell types, dominated by trophoblast cells and immune cells. In addition, trophoblast cells were divided into four subtypes, including cytotrophoblast cells (CTBs), villous cytotrophoblasts (VCTs), syncytiotrophoblast (STB), and extravillous trophoblasts (EVTs). Immune cells are divided into lymphocytes and macrophages, of which macrophages have 3 subtypes (decidual macrophages, Hofbauer cells and macrophages), and lymphocytes have 4 subtypes (BloodNK, T cells, plasma cells, and decidual natural killer cells). Meanwhile, we also proved the orderly differentiation sequence of CTB into VCT, then STB and EVT. By pair-wise analysis of the expression and enrichment of differentially expressed genes in trophoblast cells between PE, GDM and control, it was found that these cells were involved in immune, nutrient transfer, hormone and oxidative stress pathways. In addition, T cells and macrophages play an immune defense role in both PE and GDM. The proportion of CTB and EVT cells in placental tissue was confirmed by flow cytometry. Taken together, our results suggested that the human placenta is a dynamic heterogenous organ dominated by trophoblast and immune cells, which perform their respective roles and interact with other cells in the environment to maintain normal placental function.

Exploring the presence of markers of decidualization in the fallopian tubes: a systematic review

The fallopian tubes (FTs) are part of the female upper genital tract. The healthy FT provides the biological environment for successful fertilization and facilitates the subsequent movement of the conceptus to the endometrial cavity. However, when the FT is damaged, as with salpingitis, pyosalpinx, and hydrosalpinx, it may increase the risk of an ectopic pregnancy, a life-threatening condition. Decidualization refers to a multifactorial process by which the endometrium changes to permit blastocyst implantation. The decidualization reaction is vital for endometrial receptivity during the window of implantation. To date, no comprehensive review that collates evidence on decidualization in the human FT has been conducted. Therefore, the aim of this review is to compile the current evidence on cellular decidualization occurring in the healthy and pathological FT in women of reproductive age. A literature search was conducted using five databases and identified 746 articles, 24 of which were analyzed based on inclusion and exclusion criteria. The available evidence indicates that the FT are able to undergo decidual changes under specific circumstances; however, the exact mechanism by which this occurs is poorly understood. Further research is needed to elucidate the mechanism by which decidualization can occur in the FT.

Downregulation of miR-92a in Decidual Stromal Cells Suppresses Migration Ability of Trophoblasts by Promoting Macrophage Polarization

Preeclampsia (PE) is a severe pregnancy complication that accounts for about 14% of maternal deaths. Its clinical manifestations commonly include hypertension and proteinuria. However, it is largely limited in understanding its pathogenetic mechanism. In this study, we used bioinformatics to compare differential gene expressions in decidual stromal cells from PE patients and healthy donors. The result indicated that higher levels of CCL5 and CXCL2 were expressed in decidual stromal cells of PE patients compared with healthy pregnancy. The bioinformatics analysis confirmed that decidual stromal cells derived from PE patients expressed significantly lower miR-92a compared with those derived from healthy donors. Transfection of miR-92a inhibitors upregulated IL-6, CXCL2, CXCL3, CCL5, and CXCL8 expressions in decidual stromal cells. Luciferase activity assay confirmed that miR-92a directly targeted the mRNA of IRF3 whose overexpression could promote the secretion of cytokines. The flow cytometric analysis demonstrated that M1 macrophage infiltration was higher in the placentas of PE patients than in those of healthy donors. We also observed that after transfection of miR-92a inhibitor, condition medium (CM) derived from decidual stromal cells significantly promoted M1 polarization of macrophages. In addition, the transwell migration assay and flow cytometric analysis together showed that decidual stromal cell-derived CM induced macrophages to suppress the trophoblast migration and proliferation. Taken together, our result indicates that downregulation of miR-92a in decidual stromal cells promotes the macrophage polarization and suppresses the trophoblast migration and proliferation.

Immune plasticity in pregnancy-associated breast cancer tumorigenesis

Pregnancy-associated breast cancer (PrBC) is a rare tumor that requires complex management. The coexistence of cancer and pregnancy involves several proliferative, invasive, and immune tolerance mechanisms that are shared between the two conditions. In normal pregnancy, successful fetal development is achieved through suppression of the maternal immune response toward the fetus. Similar immunosuppressive patterns during the malignant transformation supporting tumor growth, progression, and metastasis are also exhibited by tumors. An improved understanding of the immunosuppressive mechanisms and pathways underlying the immunological synergy in PrBC could lead to the identification of novel biomarkers that potentially improve patients' clinical management. In this review article, we outline some of the paramount features of immune plasticity during pregnancy, discussing the similarities shared between normal pregnancy and breast cancer in terms of immune suppression mechanisms. Emphasis is also placed on how the current knowledge of the immune milieu of these conditions may be translated into consequent therapeutic opportunities.

Resveratrol reliefs DEHP-induced defects during human decidualization

Di-(2-Ethylhexyl) phthalate (DEHP) is widely used as an additive in many plastic products. Studies have revealed that DEHP persistent exposure can affect embryonic development and lead to adverse female reproductive disorders. The establishment of pregnancy involves extensive changes in the endometrial tissue, including massive extracellular matrix (ECM) remodeling. Decidualization of the endometrium provides a suitable environment for subsequent growth by causing changes in the morphology of the uterine stromal cells, is a key process in human pregnancy. Resveratrol (RSV) is a natural polyphenolic plant antitoxin with a wide range of pharmacological effects. Growing evidence indicates that RSV has therapeutic effects on certain female reproductive disorders. In this study, the effect of DEHP on cell viability was investigated by cell proliferation assay. Cell decidualization was induced in vitro, and the downregulation of molecules associated with decidualization was confirmed through quantitative real-time PCR and western blot analysis. Immunofluorescence analysis revealed alteration in cell morphology, and found that administration of DEHP sufficiently induced ERα entry into the nucleus. The effect of DEHP on cells was fully verified by RNA-seq analysis. Interestingly, an upregulation of decidual molecules was observed after rescue with RSV, which was confirmed by RNA-seq transcriptome analysis and quantitative real-time PCR assay. Additionally, the expression of ECM remodeling-related genes was significantly restored by RSV administration. The study revealed the potential mechanisms of DEHP-induced decidualization defects and the functional relieving roles of RSV while providing a perspective therapeutic candidate for alleviating the DEHP-induced deficiencies in decidualization.

A Microphysiological Device to Model the Choriodecidual Interface Immune Status during Pregnancy

During human pregnancy the chorion (fetal) lines decidua (maternal) creating the feto-maternal interface. Despite their proximity, resident decidual immune cells remain quiescent during gestation and do not invade the chorion. Infection and infiltration of activated immune cells toward the chorion are often associated with preterm birth. However, the mechanisms that maintain choriodecidual immune homeostasis or compromise immune barrier functions remain unclear. To understand these processes, a two-chamber microphysiological system (MPS) was created to model the human choriodecidual immune interface under normal and infectious conditions in vitro. This MPS has outer (fetal chorion trophoblast cells) and inner chambers (maternal decidual + CD45+ cells [70:30 ratio]) connected by microchannels. Decidual cells were treated with LPS to mimic maternal infection, followed by immunostaining for HLA-DR and HLA-G, immune panel screening by imaging cytometry by time of flight, and immune regulatory factors IL-8 and IL-10, soluble HLA-G, and progesterone (ELISA). LPS induced a proinflammatory phenotype in the decidua characterized by a decrease in HLA-DR and an increase in IL-8 compared with controls. LPS treatment increased the influx of immune cells into the chorion, indicative of chorionitis. Cytometry by time of flight characterized immune cells in both chambers as active NK cells and neutrophils, with a decrease in the abundance of nonproinflammatory cytokine-producing NK cells and T cells. Conversely, chorion cells increased progesterone and soluble HLA-G production while maintaining HLA-G expression. These results highlight the utility of MPS to model choriodecidual immune cell infiltration and determine the complex maternal-fetal crosstalk to regulate immune balance during infection.

The effects of progesterone on immune cellular function at the maternal-fetal interface and in maternal circulation

Progesterone is a sex steroid hormone that plays a critical role in the establishment and maintenance of pregnancy. This hormone drives numerous maternal physiological adaptations to ensure the continuation of pregnancy and to facilitate fetal growth, including broad and potent modulation of the maternal immune system to promote maternal-fetal tolerance. In this brief review, we provide an overview of the immunomodulatory functions of progesterone in the decidua, placenta, myometrium, and maternal circulation during pregnancy. Specifically, we summarize current evidence of the regulated functions of innate and adaptive immune cells induced by progesterone and its downstream effector molecules in these compartments, including observations in human pregnancy and in animal models. Our review highlights the gaps in knowledge of interactions between progesterone and maternal cellular immunity that may direct future research.

Innate immune cellular therapeutics in transplantation

Successful organ transplantation provides an opportunity to extend the lives of patients with end-stage organ failure. Selectively suppressing the donor-specific alloimmune response, however, remains challenging without the continuous use of non-specific immunosuppressive medications, which have multiple adverse effects including elevated risks of infection, chronic kidney injury, cardiovascular disease, and cancer. Efforts to promote allograft tolerance have focused on manipulating the adaptive immune response, but long-term allograft survival rates remain disappointing. In recent years, the innate immune system has become an attractive therapeutic target for the prevention and treatment of transplant organ rejection. Indeed, contemporary studies demonstrate that innate immune cells participate in both the initial alloimmune response and chronic allograft rejection and undergo non-permanent functional reprogramming in a phenomenon termed "trained immunity." Several types of innate immune cells are currently under investigation as potential therapeutics in transplantation, including myeloid-derived suppressor cells, dendritic cells, regulatory macrophages, natural killer cells, and innate lymphoid cells. In this review, we discuss the features and functions of these cell types, with a focus on their role in the alloimmune response. We examine their potential application as therapeutics to prevent or treat allograft rejection, as well as challenges in their clinical translation and future directions for investigation.

Decreased ratio of FOXP3+/FOXP3-CD45RA+CD4+ T cells in peripheral blood is associated with unexplained infertility and ART failure

Unexplained infertility has a huge social impact and is a significant challenge for both clinicians and researchers. Previous studies have shown the involvement of multiple factors in infertility. Among these, the subset of regulatory T cells is of particular interest for the maternal tolerance towards the semi-allogenic fetus. We investigated circulating CD45RA⁺ regulatory and non-regulatory CD4⁺ T cells in healthy women and patients with unexplained infertility in the context of thymic output and peripheral proliferation. The proportion of FOXP3⁺ and FOXP3^-CD45RA⁺CD4⁺ T cells in peripheral blood was studied in control groups of healthy parous and nulliparous (never-pregnant) women and in patients with unexplained infertility. In the same groups thymic output and peripheral proliferation were defined by the sj/βTREC ratio, and signal joint T-cell receptor excision circles (sjTREC) and Ki67 expression, respectively. In parous women a decrease in sjTREC/10⁵ cells and CD45RA⁺ T lymphocytes, compared to nulliparous group was found. At the same time, the proportion of FOXP3^-CD45RA⁺CD4⁺ cells, but not FOXP3⁺CD45RA⁺ Tregs was reduced. In contrast, in patients with unsuccessful pregnancy, proportions of both regulatory and non-regulatory T cell counterparts were lower. Taken together, our results provide evidence for group-specific properties in the CD45RA⁺ T cell compartment between healthy parous, nulliparous and women with unexplained infertility.

Recurrent implantation failure: A comprehensive summary from etiology to treatment

Implantation is the first step in human reproduction. Successful implantation depends on the crosstalk between embryo and endometrium. Recurrent implantation failure (RIF) is a clinical phenomenon characterized by a lack of implantation after the transfer of several embryos and disturbs approximately 10% couples undergoing in vitro fertilization and embryo transfer. Despite increasing literature on RIF, there is still no widely accepted definition or standard protocol for the diagnosis and treatment of RIF. Progress in predicting and preventing RIF has been hampered by a lack of widely accepted definitions. Most couples with RIF can become pregnant after clinical intervention. The prognosis for couples with RIF is related to maternal age. RIF can be caused by immunology, thrombophilias, endometrial receptivity, microbiome, anatomical abnormalities, male factors, and embryo aneuploidy. It is important to determine the most possible etiologies, and individualized treatment aimed at the primary cause seems to be an effective method for increasing the implantation rate. Couples with RIF require psychological support and appropriate clinical intervention. Further studies are required to evaluate diagnostic method and he effectiveness of each therapy, and guide clinical treatment.

Endometrial stromal cell miR-19b-3p release is reduced during decidualization implying a role in decidual-trophoblast cross-talk

INTRODUCTION

A healthy pregnancy requires successful blastocyst implantation into an adequately prepared or 'receptive' endometrium. Decidualization of uterine endometrial stromal fibroblast cells (hESF) is critical for the establishment of a healthy pregnancy. microRNAs (miRs) are critical regulators of cellular function that can be released by a donor cell to influence the physiological state of recipient cells. We aimed to determine how decidualization affects hESF miR release and investigated the function of one decidualization regulated miR, miR-19b-3p, previously shown to be associated with recurrent pregnancy loss.

METHOD

miR release by hESF was determined by miR microarray on culture media from hESF decidualized in vitro for 3 and 14 days by treatment with oestradiol and medroxyprogesterone acetate. Cellular and whole endometrial/decidual tissue miR expression was quantified by qPCR and localized by in situ hybridization. The function of miR-19b-3p in HTR8/Svneo trophoblast cells was investigated using real time cell analysis (xCELLigence) and gene expression qPCR.

RESULTS

From our miR screen we found that essentially all hESF miR release was reduced following in vitro decidualization, significantly so for miR-17-5p, miR-21-3p, miR-34c-3p, miR-106b-5p, miR-138-5p, miR-296-5p, miR-323a-3p, miR-342-3p, miR-491-5p, miR-503-5p and miR-542-5p. qPCR demonstrated that miR-19b-3p, 181a-2-3p and miR-409-5p likewise showed a significant reduction in culture media following decidualization but no change was found in cellular miR expression following decidualization. In situ hybridization localized miR-19b-3p to epithelial and stromal cells in the endometrium and qPCR identified that miR-19b-3p was significantly elevated in the cycling endometrium of patients with a history of early pregnancy loss compared to normally fertile controls. Functionally, overexpression of miR-19b-3p significantly reduced HTR8/Svneo trophoblast proliferation and increased HOXA9 expression.

DISCUSSION

Our data demonstrates that decidualization represses miR release by hESFs and overexpression of miR-19b-3p was found in endometrial tissue from patients with a history of early pregnancy loss. miR-19b-3p impaired HTR8/Svneo proliferation implying a role in trophoblast function. Overall we speculate that miR release by hESF may regulate other cell types within the decidua and that appropriate release of miRs by decidualized hESF is essential for healthy implantation and placentation.

Interleukin-15 deficient rats have reduced osteopontin at the maternal-fetal interface

Introduction: Uterine Natural Killer (NK) cells are the predominant immune cells within the decidua during early pregnancy. These cells are thought to regulate aspects of decidualization and placental development, but their functions remain poorly characterized, especially in species with deeply invading trophoblasts such as humans and rats. Interleukin-15 (IL-15) is a cytokine required for NK cell development and survival. IL-15 mutant (IL15Δ/Δ) rats lack NK cells and exhibit altered placental development with precocious trophoblast invasion. In this study, we profiled gene expression differences between wild-type and IL15Δ/Δ implantation sites to reveal candidate factors produced by uterine NK cells that may regulate placentation and trophoblast invasion. Methods: Clariom S gene expression profiling was performed using implantation sites collected from pregnant wild-type and IL15Δ/Δ rats on gestational day 9.5. Levels and localization of perforin and osteopontin in implantation sites from wild-type and IL15Δ/Δ rats were further analyzed. The effect of osteopontin on the invasive capacity of rat trophoblasts was evaluated using Matrigel-based Transwell assays. Results: There were 257 genes differentially expressed between wild-type and IL15Δ/Δ implantation sites on gestational day 9.5, including decreased expression of various NK cell markers in IL15Δ/Δ rats, as well as Spp1, which encodes osteopontin. In wild-type rats, osteopontin was present within the decidua basalis and adjacent to the primitive placenta, and osteopontin colocalized with the NK cell marker perforin. Osteopontin was also detectable in uterine glands. Conversely, in IL15Δ/Δ rats, osteopontin and perforin were not readily detectable in the decidua despite robust osteopontin levels in uterine glands. Neutralization of osteopontin in media conditioned by cells isolated from the decidua decreased invasion of rat trophoblasts, suggesting that reduced levels of osteopontin are unlikely to account for the precocious trophoblast invasion in IL15Δ/Δ rats. Conclusion: Osteopontin is expressed by NK cells at the maternal-fetal interface in rats and may contribute to modulation of trophoblast invasion.

Peroxisome proliferator-activated receptor pathways in diabetic rat decidua early after implantation: regulation by dietary polyunsaturated fatty acids

RESEARCH QUESTION

Are peroxisome proliferator-activated receptor (PPAR) pathways and moieties involved in histotrophic nutrition altered in the decidua of diabetic rats? Can diets enriched in polyunsaturated fatty acids (PUFA) administered early after implantation prevent these alterations? Can these dietary treatments improve morphological parameters in the fetus, decidua and placenta after placentation?

DESIGN

Streptozotocin-induced diabetic Albino Wistar rats were fed a standard diet or diets enriched in n3- or n6-PUFAs early after implantation. Decidual samples were collected on day 9 of pregnancy. Fetal, decidual and placental morphological parameters were evaluated on day 14 of pregnancy.

RESULTS

On gestational day 9, PPARδ levels showed no changes in the diabetic rat decidua compared with controls. In diabetic rat decidua, PPARα levels and the expression of its target genes Aco and Cpt1 had reduced. These alterations were prevented by the n6-PUFA-enriched diet. Levels of PPARγ, the expression of its target gene Fas, lipid droplet number and perilipin 2 and fatty acid binding protein 4 levels increased in the diabetic rat decidua compared with controls. Diets enriched with PUFA prevented PPARγ increase, but not the increased lipid-related PPARγ targets. On gestational day 14, fetal growth, decidual and placental weight reduced in the diabetic group, and alterations prevented by the maternal diets were enriched in PUFAs.

CONCLUSION

When diabetic rats are fed diets enriched in n3- and n6-PUFAs early after implantation, PPAR pathways, lipid-related genes and proteins, lipid droplets and glycogen content in the decidua are modulated. This influences decidual histotrophic function and later feto-placental development.

Single-Cell RNA-Sequencing Reveals Interactions between Endometrial Stromal Cells, Epithelial Cells, and Lymphocytes during Mouse Embryo Implantation

The decidualization of endometrial stromal cells (ESCs) is an essential process facilitating embryo implantation. However, the roles of non-decidualized and decidualized ESCs in regulating the microenvironment of a receptive endometrium remain unclear. We investigated single-cell transcriptomic changes in the uterus of a CD-1 mouse model at the post-implantation stage. The implantation and inter-implantation sites of the uteruses of pregnant mice at 4.5 and 5.5 days post-coitum were dissected for single-cell RNA sequencing. We identified eight cell types: epithelial cells, stromal cells, endothelial cells, mesothelial cells, lymphocytes, myocytes, myeloids, and pericytes. The ESC transcriptome suggests that the four ESC subtypes are involved in the extracellular remodeling during implantation. The trajectory plot of ESC subtypes indicates embryo implantation that involves a differentiation pathway from undifferentiated ESCs (ESC 1) to decidualized ESCs (DEC ESCs), with distinct signaling pathways between the ESC subtypes. Furthermore, the ligand-receptor analysis suggests that ESCs communicate with epithelial cells and immune cells through nectin and ICAM signaling. Collectively, both decidualized and non-decidualized ESCs may regulate the endometrial microenvironment for optimal endometrial receptivity and immune tolerance. This study provides insights on the molecular and cellular characteristics of mouse ESCs in modulating the epithelial and lymphocyte functions during early embryo implantation.

Human decidual gamma/delta T cells possess unique effector and TCR repertoire profiles during pregnancy

Human γδ T cells are enriched at the maternal-fetal interface (MFI, decidua basalis) showing a highly differentiated phenotype. However, their functional potential is not well-known and it is not clear whether this decidua-enrichment is associated with specific γδ T cell receptors (TCR) as is observed in mice. Here we addressed these open questions by investigating decidual γδ T cells during early and late gestation, in comparison with paired blood samples, with flow cytometry (cytotoxic mediators, cytokines) and TCR high-throughput sequencing. While decidual γδ T cells expressed less perforin than their counterparts in the blood, they expressed significant more granulysin during early pregnancy. Strikingly, this high granulysin expression was limited to early pregnancy, as it was reduced at term pregnancy. In contrast to this granulysin expression pattern, decidual γδ T cells produced reduced levels of IFNγ and TNFα (compared to paired blood) in early pregnancy that then increased by term pregnancy. TCR repertoire analysis indicated that human decidual γδ T cells are not generated early in life as in the mouse. Despite this, a specific enrichment of the Vγ2 chain in the decidua in early pregnancy was observed that disappeared later onwards, reflecting dynamic changes in the decidual γδ TCR repertoire during human gestation. In conclusion, our data indicate that decidual γδ T cells express a specific and dynamic pattern of cytotoxic mediators, Th1 cytokines and TCR repertoire suggesting an important role for these unconventional T cells in assuring a healthy pregnancy in human.

Anti-glomerular basement membrane disease with rupture of the newly formed bilateral corpus luteum cysts: A case report

RATIONALE

Anti-glomerular basement membrane (anti-GBM) disease during gestation is sparse and even rarer when combined with bilateral large corpus luteum cysts. In this case, we report a case of anti-GBM disease in the early stage of pregnancy with ruptured newly formed bilateral large corpus luteum cysts.

PATIENT CONCERNS

A 24-year-old female was initially diagnosed with anti-GBM disease. During treatment, abdominal distention and vaginal bleeding successively staged. The results of the first gynecological ultrasound and abdominal CT were negative.

DIAGNOSIS

Based on the dynamic imaging change of the ovaries, the elevated human chorionic gonadotropin (hCG) and sex hormones, and the pathological findings, a diagnosis of anti-GBM disease with rupture of the newly formed bilateral corpus luteum cysts during early pregnancy was considered.

INTERVENTIONS

The patient was treated with corticosteroids, plasma-exchange along with intensive hemodialysis. Then, to confirm the diagnosis, laparoscopic debulking of bilateral ovarian cysts and curettage were performed.

OUTCOMES

After treatment, the anti-GBM antibody titer declined and the condition of the patient was still stable 2 months following discharge.

LESSONS

As clinicians, we should be aware that even if the first imaging tests are negative, the relevant indicators should be reviewed dynamically based on the condition of the patients. Additionally, this case raised the question of whether anti-GBM disease was associated with pregnancy and giant corpus luteum cysts, which needs further investigations.

Endometrium Immunomodulation to Prevent Recurrent Implantation Failure in Assisted Reproductive Technology

After more than four decades of assisted reproductive technology (ART) practice worldwide, today more than 60% of women undergoing in vitro fertilization (IVF) treatments fail to become pregnant after the first embryo transfer and nearly 20% of patients are suffering from unexplained recurrent implantation failures (RIFs) and repeated pregnancy loss (RPL). The literature reported different causes of RIF–RPL, mainly multifactorial, endometrial and idiopathic. RIF remains a black box because of the complicated categorization and causes of this physio-pathological dysregulation of implantation and pregnancy process after ovarian stimulation. Many options were suggested as solutions to treat RIF–RPL with controversial results on their usefulness. In this article, we reviewed different possible therapeutic options to improve implantation rates and clinical outcomes. Based on our experience we believe that endometrium immunomodulation after intrauterine insemination of activated autologous peripheral blood mononuclear cells (PBMCs) or platelet-rich plasma (PRP) can be a promising therapeutic solution. On the other hand, peripheral lymphocyte balance typing, specific cytokines and interleukins profiling can be proposed as predictive biomarkers of implantation before embryo transfer.

Single-Cell Immunobiology of the Maternal-Fetal Interface

Pregnancy success requires constant dialogue between the mother and developing conceptus. Such crosstalk is facilitated through complex interactions between maternal and fetal cells at distinct tissue sites, collectively termed the "maternal-fetal interface." The emergence of single-cell technologies has enabled a deeper understanding of the unique processes taking place at the maternal-fetal interface as well as the discovery of novel pathways and immune and nonimmune cell types. Single-cell approaches have also been applied to decipher the cellular dynamics throughout pregnancy, in parturition, and in obstetrical syndromes such as recurrent spontaneous abortion, preeclampsia, and preterm labor. Furthermore, single-cell technologies have been used during the recent COVID-19 pandemic to evaluate placental viral cell entry and the impact of SARS-CoV-2 infection on maternal and fetal immunity. In this brief review, we summarize the current knowledge of cellular immunobiology in pregnancy and its complications that has been generated through single-cell investigations of the maternal-fetal interface.

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.

A defective lysophosphatidic acid-autophagy axis increases miscarriage risk by restricting decidual macrophage residence

Massive infiltrated and enriched decidual macrophages (dMφ) have been widely regarded as important regulators of maternal-fetal immune tolerance and trophoblast invasion, contributing to normal pregnancy. However, the characteristics of metabolic profile and the underlying mechanism of dMφ residence remain largely unknown. Here, we observe that dMφ display an active glycerophospholipid metabolism. The activation of ENPP2-lysophosphatidic acid (LPA) facilitates the adhesion and retention, and M2 differentiation of dMφ during normal pregnancy. Mechanistically, this process is mediated through activation of the LPA receptors (LPAR1 and PPARG/PPARγ)-DDIT4-macroautophagy/autophagy axis, and further upregulation of multiple adhesion factors (e.g., cadherins and selectins) in a CLDN7 (claudin 7)-dependent manner. Additionally, poor trophoblast invasion and placenta development, and a high ratio of embryo loss are observed in Enpp2^±, lpar1^-/- or PPARG-blocked pregnant mice. Patients with unexplained spontaneous abortion display insufficient autophagy and cell residence of dMφ. In therapeutic studies, supplementation with LPA or the autophagy inducer rapamycin significantly promotes dMφ autophagy and cell residence, and improves embryo resorption in Enpp2^± and spontaneous abortion mouse models, which should be dependent on the activation of DDIT4-autophagy-CLDN7-adhesion molecules axis. This observation reveals that inactivation of ENPP2-LPA metabolism and insufficient autophagy of dMφ result in resident obstacle of dMφ and further increase the risk of spontaneous abortion, and provides potential therapeutic strategies to prevent spontaneous abortion.Abbreviations: ACTB: actin beta; ADGRE1/F4/80: adhesion G protein-coupled receptor E1; Atg5: autophagy related 5; ATG13: autophagy related 13; BECN1: beclin 1; CDH1/E-cadherin: cadherin 1; CDH5/VE-cadherin: cadherin 5; CFSE: carboxyfluorescein succinimidyl ester; CLDN7: claudin 7; CSF1/M-CSF: colony stimulating factor 1; CSF2/GM-CSF: colony stimulating factor 2; Ctrl: control; CXCL10/IP-10: chemokine (C-X-C) ligand 10; DDIT4: DNA damage inducible transcript 4; dMφ: decidual macrophage; DSC: decidual stromal cells; ENPP2/ATX: ectonucleotide pyrophosphatase/phosphodiesterase 2; Enpp2^±: Enpp2 heterozygous knockout mouse; ENPP2i/PF-8380: ENPP2 inhibitor; EPCAM: epithelial cell adhesion molecule; ESC: endometrial stromal cells; FGF2/b-FGF: fibroblast growth factor 2; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GPCPD1: glycerophosphocholine phosphodiesterase 1; HE: heterozygote; HIF1A: hypoxia inducible factor 1 subunit alpha; HNF4A: hepatocyte nuclear factor 4 alpha; HO: homozygote; ICAM2: intercellular adhesion molecule 2; IL: interleukin; ITGAV/CD51: integrin subunit alpha V; ITGAM/CD11b: integrin subunit alpha M; ITGAX/CD11b: integrin subunit alpha X; ITGB3/CD61: integrin subunit beta 3; KLRB1/NK1.1: killer cell lectin like receptor B1; KRT7/cytokeratin 7: keratin 7; LPA: lysophosphatidic acid; LPAR: lysophosphatidic acid receptor; lpar1^-/-: lpar1 homozygous knockout mouse; LPAR1i/AM966: LPAR1 inhibitor; LY6C: lymphocyte antigen 6 complex, locus C1; LYPLA1: lysophospholipase 1; LYPLA2: lysophospholipase 2; Lyz2: lysozyme 2; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; MARVELD2: MARVEL domain containing 2; 3-MA: 3-methyladenine; MBOAT2: membrane bound O-acyltransferase domain containing 2; MGLL: monoglyceride lipase; MRC1/CD206: mannose receptor C-type 1; MTOR: mechanistic target of rapamycin kinase; NP: normal pregnancy; PDGF: platelet derived growth factor; PLA1A: phospholipase A1 member A; PLA2G4A: phospholipase A2 group IVA; PLPP1: phospholipid phosphatase 1; pMo: peripheral blood monocytes; p-MTOR: phosphorylated MTOR; PPAR: peroxisome proliferator activated receptor; PPARG/PPARγ: peroxisome proliferator activated receptor gamma; PPARGi/GW9662: PPARG inhibitor; PTPRC/CD45: protein tyrosine phosphatase receptor type, C; Rapa: rapamycin; RHEB: Ras homolog, mTORC1 binding; SA: spontaneous abortion; SELE: selectin E; SELL: selectin L; siCLDN7: CLDN7-silenced; STAT: signal transducer and activator of transcription; SQSTM1: sequestosome 1; TJP1: tight junction protein 1; VCAM1: vascular cell adhesion molecule 1; WT: wild type.

Temporal changes in cyclinD-CDK4/CDK6 and cyclinE-CDK2 pathways: implications for the mechanism of deficient decidualization in an immune-based mouse model of unexplained recurrent spontaneous abortion

BACKGROUND

Deficient endometrial decidualization has been associated with URSA. However, the underlying mechanism is poorly understood. This study aimed to investigate the temporal cytokine changes and the involvement of CyclinD-CDK4/6 and CyclinE-CDK2 pathways in the regulation of the G1 phase of the cell cycle during decidualization in a murine model of URSA.

METHODS

Serum and decidual tissues of mice were collected from GD4 to GD8. The embryo resorption and abortion rates were observed on GD8 and the decidual tissue status was assessed. In addition, PRL, Cyclin D, CDK6, CDK4, Cyclin E, CDK2 expression in mice were measured.

RESULTS

URSA mice showed high embryo resorption rate and PRL, Cyclin D, Cyclin E CDK2, CDK4, CDK6 down-regulation during decidualization. The hyperactivated Cyclin D-CDK4/CDK6 and cyclin E/CDK2 pathways inhibit the decidualization process and leading to deficient decidualization.

CONCLUSION

Insufficient decidualization is an important mechanism of URSA. which is related to the decrease of Cyclin D、Cyclin E、 CDK2、CDK4 and CDK6 in decidualization process of URSA.