Single-cell profiling reveals immune disturbances landscape and HLA-F-mediated immune tolerance at the maternal-fetal interface in preeclampsia

The NFE2L2 (NRF2) transcription factor controls genes involved in the oxidative stress response and inflammation in myometrial cells

The myometrium is the smooth muscle layer of the uterus, which mediates uterine contractions during labor. We treated PHM1-31 myometrial cells with the proinflammatory cytokine interleukin-1 beta (IL1B) and measured a significant increase in reactive oxygen species (ROS). We found that IL1B induces NFE2L2 (NRF2) transcription factor levels. We further showed that siRNA mediated knockdown of NFE2L2 results in a significant increase in ROS. Downregulation of NFE2L2 leads to a decrease of heme oxygenase-1 (HMOX1) and aldo-keto reductase family 1 member B (AKR1B) at the transcript and protein level both in the absence and presence of IL1B. NFE2L2 knockdown also results in reduced ferritin heavy chain 1 (FTH1) mRNA expression, but only upon IL1B exposure, while FTH1 protein is downregulated both under basal and IL1B treatment conditions. We confirmed that NFE2L2 directly binds to the regulatory regions of these targets. Previous reports have linked HMOX1 and FTH1 to the oxidative stress response, and AKR1B1 to prostaglandin synthesis. Our data demonstrate that NFE2L2 functions as a key regulator of inflammatory and oxidative stress signaling through the regulation of HMOX1, FTH1, and AKR1B1 expression in myometrial cells. While HMOX1 and FTH1 have established roles in oxidative stress responses, our findings identify AKR1B1 as a novel target of NFE2L2 in myometrial cells, suggesting a role for the transcription factor in prostaglandin metabolism. Thus, NFE2L2 links inflammation and the oxidative stress response to critical pathways that control myometrial cell function and parturition, highlighting their potential as therapeutic targets for treating infection-induced preterm labor.

HLA-F regulates the proliferation of trophoblast via PKM2-dependent glycolysis in the pathogenesis of preeclampsia

BACKGROUND

The regulatory molecule Human Leukocyte Antigen F (HLA-F) has been implicated in trophoblast proliferation during pregnancy, and reduced levels of this antigen have been identified in trophoblast cells of patients with preeclampsia. This study aimed to analyze the effect and mechanism of HLA-F on the proliferation of trophoblast and the underlying mechanism of reduced HLA-F involved in preeclampsia.

METHODS

q-PCR, Western blot (WB), and Immunohistochemistry (IHC) were used to detect the expression of HLA-F and Pyruvate Kinase Muscle isoform 2 (PKM2) in placenta tissues. Jar cells were transfected with overexpression lentivirus, specific siRNA, and shRNA to regulate corresponding genes. Immunofluorescence was used to analyze the expression and distribution of HLA-F and PKM2. Extracellular and intracellular lactate, pyruvate, and enzymatic activity of PKM2 were measured using the corresponding assay kits. Cell proliferation was measured by CCK8, MTT, colony formation assay, and Mini patient-derived xenograft (Mini-PDX). Chromatin Immunoprecipitation and deep sequencing (ChIP-seq) and 4-dimensional label-free quantitative proteomics (4D-LFQP-LA) were used to analyze the HLA-F-binding DNA sequences and the differential lactylation proteins in HLA-F-overexpression Jar and its control.

RESULTS

The expression of HLA-F is reduced in extravillous trophoblast and villous cytotrophoblast from patients with preeclampsia. Over-expression of HLA-F promoted proliferation while under-expression inhibited it. Further experiments demonstrated that over-expression of HLA-F promoted expression of the PKM2 protein and its enzymatic activity, resulting in enhanced glycolysis in Jar cells. Specifically, we determined that HLA-F regulated the expression of PKM2 by binding the promoter of PKM, and promoted PKM2 enzyme activity by down-regulating the lactylation of residue K305. Moreover, silencing PKM2 with siRNA reduced HLA-F-mediated glycolysis and proliferation in HLA-F-overexpressing Jar cells. Finally, we corroborated these results using a MiniPDX model, with which we confirmed that the PKM2 agonist TEPP-46 promoted the proliferation of ShHLA-F Jar cells.

CONCLUSIONS

The reduced expression of HLA-F in placental trophoblast cells resulted in the downregulation of both PKM2 transcription and protein expression. Concurrently, the relative upregulation of lactylation at PKM2 K305 contributed to a decline in enzyme activity, further exacerbating glycolysis dysfunction. Collectively, these alterations led to a suppression of trophoblast proliferation capacity and involvement in the pathogenesis of preeclampsia.

Deciphering the preeclampsia-specific immune microenvironment and the role of pro-inflammatory macrophages at the maternal-fetal interface

Preeclampsia (PE), a major cause of maternal and perinatal mortality with highly heterogeneous causes and symptoms, is usually complicated by gestational diabetes mellitus (GDM). However, a comprehensive understanding of the immune microenvironment in the placenta of PE and the differences between PE and GDM is still lacking. In this study, cytometry by time of flight indicated that the frequencies of memory-like Th17 cells (CD45RA-CCR7+IL-17A+CD4+), memory-like CD8+ T cells (CD38+CXCR3-CCR7+Helios-CD127-CD8+) and pro-inflam Macs (CD206-CD163-CD38midCD107alowCD86midHLA-DRmidCD14+) were increased, while the frequencies of anti-inflam Macs (CD206+CD163-CD86midCD33+HLA-DR+CD14+) and granulocyte myeloid-derived suppressor cells (gMDSCs, CD11b+CD15hiHLA-DRlow) were decreased in the placenta of PE compared with that of normal pregnancy (NP), but not in that of GDM or GDM&PE. The pro-inflam Macs were positively correlated with memory-like Th17 cells and memory-like CD8+ T cells but negatively correlated with gMDSCs. Single-cell RNA sequencing revealed that transferring the F4/80+CD206- pro-inflam Macs with a Folr2+Ccl7+Ccl8+C1qa+C1qb+C1qc+ phenotype from the uterus of PE mice to normal pregnant mice induced the production of memory-like IL-17a+Rora+Il1r1+TNF+Cxcr6+S100a4+CD44+ Th17 cells via IGF1-IGF1R, which contributed to the development and recurrence of PE. Pro-inflam Macs also induced the production of memory-like CD8+ T cells but inhibited the production of Ly6g+S100a8+S100a9+Retnlg+Wfdc21+ gMDSCs at the maternal-fetal interface, leading to PE-like symptoms in mice. In conclusion, this study revealed the PE-specific immune cell network, which was regulated by pro-inflam Macs, providing new ideas about the pathogenesis of PE.

MicroRNA-155 targets p65 to regulate PD-L1 expression in the early pregnancy endometrium

Reproductive disorders in dairy cows represent a significant challenge to the advancement of the dairy industry. Pregnancy success is closely related to the mechanism of immune tolerance, with the PD-1/PD-L1 signaling pathway playing a role in immune regulation, which is associated with immune tolerance and pregnancy maintenance. MicroRNAs can regulate pivotal molecules within the signaling pathway, physiological activities, and disease processes. p65 and PD-L1 expression was significantly increased in the early pregnant uterine epithelium. In contrast, the expression of p65 and PD-L1 was homogeneous in the endometrial epithelium of E2 and P4 co-stimulated bEECs and changed with the stimulation time and concentration. MiR-155 expression was significantly reduced in the early pregnant uterine epithelium. p65 was identified as a molecular target of miR-155 using a dual luciferase assay and mimics/inhibitor transfection, and miR-155 inhibited p65 expression by binding to the 3'-UTR of p65 mRNA. The regulation of PD-L1 expression by p65 was confirmed through the knockdown of p65 by si-p65 and the overexpression of p65 by pcDNA3.1-p65. In the context of pregnancy, miR-155 was observed to target p65, thereby regulating PD-L1 expression at the endometrial epithelium.

Cytokine modulation and immunoregulation of uterine NK cells in pregnancy disorders

Uterine natural killer (uNK) cells play a pivotal role in promoting placental development and supporting maternal-fetal immune tolerance, primarily through cytokine regulation and growth factor production. While the importance of uNK cells in pregnancy is well-established, the mechanisms of their interactions with trophoblasts and contributions to various pregnancy complications remain incompletely understood. This review highlights recent advancements in understanding uNK cell functions, with a focus on cytokine production, growth factor secretion, and receptor-ligand interactions, particularly involving killer immunoglobulin-like receptors (KIR) and human leukocyte antigen-C (HLA-C). We explore how uNK cell dysfunction contributes to pregnancy complications, including preeclampsia, recurrent pregnancy loss, and placenta accreta spectrum (PAS) disorders, emphasizing their roles in immune tolerance and placental health. By detailing the distinct cytokine signaling pathways and functional subtypes of uNK cells, this review provides insights into their regulatory mechanisms essential for pregnancy maintenance. Additionally, we discuss emerging therapeutic strategies targeting uNK-trophoblast interactions and propose future research directions, including the development of non-invasive biomarkers and personalized interventions. This comprehensive review addresses critical knowledge gaps, aiming to advance research in reproductive immunology and guide therapeutic innovations in maternal health.

Development of immune-derived molecular markers for preeclampsia based on multiple machine learning algorithms

Preeclampsia (PE) is a major pregnancy-specific cardiovascular complication posing latent life-threatening risks to mothers and neonates. The contribution of immune dysregulation to PE is not fully understood, highlighting the need to explore molecular markers and their relationship with immune infiltration to potentially inform therapeutic strategies. We used bioinformatics tools to analyze gene expression data from the Gene Expression Omnibus (GEO) database using the GEOquery package in R. Differential expression analysis was performed using the DESeq2 and limma packages, followed by analysis of variance to identify immune-related differentially expressed genes (DEGs). Several machine learning algorithms, including least absolute shrinkage and selection operator (LASSO), bagged trees, and random forest (RF), were used to select immune-related signaling genes closely associated with the occurrence of PE. Our analysis identified 34 immune source-related DEGs. Using the identified PE- and immune source-related genes, we constructed a diagnostic forecasting model employing several ML algorithms. We identified six types of statistically significant immune cells in patients with PE and discovered a strong relationship between biomarkers and immune cells. Moreover, the immune-derived hub genes for PE exhibited strong binding capabilities with drugs, such as alitretinoin, tretinoin, and acitretin. This study presents a robust prediction model for PE that integrates multiple machine learning-derived immune-related biomarkers. Our results indicate that these biomarkers may outperform previously reported molecular signatures in predicting PE and provide insights into the mechanisms underlying immune dysregulation in PE. Further validation in larger cohorts could lead to their clinical application in PE prediction and treatment.

An update review of the application of single-cell RNA sequencing in pregnancy-related diseases

Reproductive success hinges on the presence of a robust and functional placenta. Examining the placenta provides insight about the progression of pregnancy and valuable information about the normal developmental trajectory of the fetus. The current limitations of using bulk RNA-sequencing (RNA-seq) analysis stem from the diverse composition of the placenta, hindering a comprehensive description of how distinct trophoblast cell expression patterns contribute to the establishment and sustenance of a successful pregnancy. At present, the transcriptional landscape of intricate tissues increasingly relies on single-cell RNA sequencing (scRNA-seq). A few investigations have utilized scRNA-seq technology to examine the codes governing transcriptome regulation in cells at the maternal-fetal interface. In this review, we explore the fundamental principles of scRNA-seq technology, offering the latest overview of human placental studies utilizing this method across various gestational weeks in both normal pregnancies and pregnancy-related diseases, including recurrent pregnancy loss (RPL), preeclampsia (PE), preterm birth, and gestational diabetes mellitus (GDM). Furthermore, we discuss the limitations and future perspectives of scRNA-seq technology within the realm of reproduction. It seems that scRNA-seq stands out as one of the crucial tools for studying the etiology of pregnancy complications. The future direction of scRNA-seq applications may involve devolving into functional biology, with a primary focus on understanding variations in transcriptional activity among highly specific cell populations. Our goal is to provide obstetricians with an updated understanding of scRNA-seq technology related to pregnancy complications, providing comprehensive understandings to aid in the diagnosis and treatment of these conditions, ultimately improving maternal and fetal prognosis.

Cross-Species Insights into Trophoblast Invasion During Placentation Governed by Immune-Featured Trophoblast Cells

Proper development of the placenta, the transient support organ forms after embryo implantation, is essential for a successful pregnancy. However, the regulation of trophoblast invasion, which is most important during placentation, remains largely unknown. Here, rats, mice, and pigs are used as biomedical models, used scRNA-seq to comparatively elucidate the regulatory mechanism of placental trophoblast invasion, and verified it using a human preeclampsia disease model combined with scStereo-seq. A dual-featured type of immune-featured trophoblast (iTrophoblast) is unexpectedly discovered. Interestingly, iTrophoblast only exists in invasive placentas and regulates trophoblast invasion during placentation. In a normally developing placenta, iTrophoblast gradually transforms from an immature state into a functional mature state as it develops. Whereas in the developmentally abnormal preeclamptic placenta, disordered iTrophoblast transformation leads to the accumulation of immature iTrophoblasts, thereby disrupting trophoblast invasion and ultimately leading to the progression of preeclampsia.

Novel insights into the heterogeneity of FOXP3 + Treg cells in drug-induced allergic reactions through single-cell transcriptomics

This study uncovers the novel heterogeneity of FOXP3 + regulatory T (Treg) cells and their pivotal role in modulating immune responses during drug-induced allergic reactions, employing cutting-edge single-cell transcriptomics. We established a mouse model for drug-induced allergic reactions and utilized single-cell RNA sequencing (scRNA-seq) to analyze the transcriptomic landscapes of FOXP3 + Treg cells isolated from affected tissues. The study involved both in vitro and in vivo approaches to evaluate the impact of FOXP3 expression levels on the immunoregulatory functions of Treg cells during allergic responses. Techniques included flow cytometry, cluster analysis, principal component analysis (PCA), CCK8 and CSFE assays for cell proliferation, LDH release assays for toxicity, ELISA for cytokine profiling, and CRISPR/Cas9 technology for gene editing. Our findings revealed significant transcriptomic heterogeneity among FOXP3 + Treg cells in the context of drug-induced allergic reactions, with distinct subpopulations exhibiting unique gene expression profiles. This heterogeneity suggests specialized roles in immune regulation. We observed a decrease in the proliferative capacity and cytokine secretion of FOXP3 + Treg cells following allergic stimulation, alongside an increase in reaction toxicity. Manipulating FOXP3 expression levels directly influenced these outcomes, where FOXP3 deletion exacerbated allergic responses, whereas its overexpression mitigated them. Notably, in vivo experiments demonstrated that FOXP3 overexpression significantly reduced the severity of allergic skin reactions in mice. Our study presents novel insights into the heterogeneity and crucial immunoregulatory role of FOXP3 + Treg cells during drug-induced allergic reactions. Overexpression of FOXP3 emerges as a potential therapeutic strategy to alleviate such allergic responses. These findings contribute significantly to our understanding of immune regulation and the development of targeted treatments for drug-induced allergies.

Placental Origins of Preeclampsia: Insights from Multi-Omic Studies

Preeclampsia (PE) is a major cause of maternal and neonatal morbidity and mortality worldwide, with the placenta playing a central role in disease pathophysiology. This review synthesizes recent advancements in understanding the molecular mechanisms underlying PE, focusing on placental genes, proteins, and genetic variants identified through multi-omic approaches. Transcriptomic studies in bulk placental tissue have identified many dysregulated genes in the PE placenta, including the PE signature gene, Fms-like tyrosine kinase 1 (FLT1). Emerging single-cell level transcriptomic data have revealed key cell types and molecular signatures implicated in placental dysfunction and PE. However, the considerable variability among studies underscores the need for standardized methodologies and larger sample sizes to enhance the reproducibility of results. Proteomic profiling of PE placentas has identified numerous PE-associated proteins, offering insights into potential biomarkers and pathways implicated in PE pathogenesis. Despite significant progress, challenges such as inconsistencies in study findings and lack of validation persist. Recent fetal genome-wide association studies have identified multiple genetic loci associated with PE, with ongoing efforts to elucidate their impact on placental gene expression and function. Future directions include the integration of multi-omic data, validation of findings in diverse PE populations and clinical subtypes, and the development of analytical approaches and experimental models to study the complex interplay of placental and maternal factors in PE etiology. These insights hold promise for improving risk prediction, diagnosis, and management of PE, ultimately reducing its burden on maternal and neonatal health.

A review of single-cell transcriptomics and epigenomics studies in maternal and child health

Single-cell sequencing technologies enhance our understanding of cellular dynamics throughout pregnancy. We outlined the workflow of single-cell sequencing techniques and reviewed single-cell studies in maternal and child health. We conducted a literature review of single cell studies on maternal and child health using PubMed. We summarized the findings from 16 single-cell atlases of the human and mammalian placenta across gestational stages and 31 single-cell studies on maternal exposures and complications including infection, obesity, diet, gestational diabetes, pre-eclampsia, environmental exposure and preterm birth. Single-cell studies provides insights on novel cell types in placenta and cell type-specific marks associated with maternal exposures and complications.

Identification of shared gene signatures and biological mechanisms between preeclampsia and polycystic ovary syndrome

Preeclampsia (PE) is one of the most common complications of pregnancy and polycystic ovary syndrome (PCOS) is a prevalent metabolic and endocrinopathy disorder in women of reproductive age. Identifying the shared genetic signatures and molecular mechanisms between PCOS and PE was the objective of this study. The intersections of WGCNA module genes, PPI module genes, and PPI hub genes revealed that 8 immunity-related genes might be shared causative genes of PE and PCOS. Further, qRT-PCR results showed that TSIX/miR-223-3p/DDX58 might play a crucial role in immune dysregulation in PE and PCOS and Spearman rank correlation analysis results illustrated the potential of DDX58 as a novel diagnostic and therapeutic target for PE and PCOS. Our study demonstrated a common disease pathway model TSIX/miR-223-3p/DDX58, illustrating that immune dysregulation may be a possible mechanism of PE and PCOS, and revealed that DDX58 might be a novel predictive target for PE and PCOS.