Protective role of macrophages from maternal-fetal interface in unvaccinated coronavirus disease 2019 pregnant women.

Pregnant women represent a high-risk population for Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection. The presence of SARS-CoV-2 has been reported in placenta from infected pregnant women, but whether the virus influences placenta immune response remains unclear. We investigated the properties of maternal-fetal interface macrophages (MFMs) in a cohort of unvaccinated women who contracted coronavirus disease 2019 (COVID-19) during their pregnancy. We reported an infiltration of CD163+ macrophages in placenta from COVID-19 women 19 whereas lymphoid compartment was not affected. Isolated MFMs exhibited nonpolarized activated signature (NOS2, IDO1, IFNG, TNF, TGFB) mainly in women infected during the second trimester of pregnancy. COVID-19 during pregnancy primed MFM to produce type I and III interferon response to SARS-CoV-2 (Wuhan and δ strains), that were unable to elicit this in MFMs from healthy pregnant women. COVID-19 also primed SARS-CoV-2 internalization by MFM in an angiotensin-converting enzyme 2-dependent manner. Activation and recall responses of MFMs were influenced by fetal sex. Collectively, these findings support a role for MFMs in the local immune response to SARS-CoV-2 infection, provide a basis for protective placental immunity in COVID-19, and highlight the interest of vaccination in pregnant women.

The role of aryl hydrocarbon receptors in nutrient metabolism and immune regulation at the maternal-fetal interface.

The maternal-fetal interface is composed of the placenta, which is affiliated with the fetus, and the maternal decidua. During pregnancy, the placenta is mainly responsible for nutrient transport and immune tolerance maintenance, which plays a key role in fetal growth and development and pregnancy maintenance. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that exists in various cell types at the maternal-fetal interface and is involved in multiple cellular processes. Recent studies have highlighted the role of AhR in regulating various physiological processes, including glucose and lipid metabolism, as well as tryptophan metabolism and immune responses, within non-pregnant tissues. This review shifts focus towards understanding how AhR modulation impacts metabolism and immune regulation at the maternal-fetal interface. This may implicate the development of pregnancy-related complications and the potential target of the AhR pathway for therapeutic strategies against poor pregnancy outcomes.

Single-cell RNA sequencing reveals heterogeneity and differential expression of the maternal-fetal interface during ICP and normal pregnancy.

OBJECTIVE: Intrahepatic cholestasis of pregnancy (ICP) can cause adverse perinatal outcomes. Previous studies have demonstrated that the placenta of an ICP pregnancy differs in morphology and gene expression from the placenta of a normal pregnancy. To date, however, the genetic mechanism by which ICP affects the placenta is poorly understood. Therefore, the aim of this study was to investigate the differences in main cell types, gene signatures, cell ratio, and functional changes in the placenta between ICP and normal pregnancy. METHODS: Single-cell RNA sequencing (scRNA-seq) technology was used to detect the gene expression of all cells at the placental maternal-fetal interface. Two individuals were analyzed - one with ICP and one without ICP. The classification of cell types was determined by a graph-based clustering algorithm. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the R software phyper () function and DAVID website. The differentially expressed genes (DEGs) encoding transcription factors (TFs) were identified using getorf and DIAMOND software. RESULTS: We identified 14 cell types and 22 distinct cell subtypes that showed unique functional properties. Additionally, we found differences in the proportions of fibroblasts 1, helper T (Th) cells, extravillous trophoblasts, and villous cytotrophoblasts, and we observed heterogeneity of gene expression between ICP and control placentas. Furthermore, we identified 263 DEGs that belonged to TF families, including zf-C2H2, HMGI/HMGY, and Homeobox. In addition, 28 imprinted genes were preferentially expressed in specific cell types, such as PEG3 and PEG10 in trophoblasts as well as DLK1 and DIO3 in fibroblasts. CONCLUSIONS: Our results revealed the differences in cell-type ratios, gene expression, and functional changes between ICP and normal placentas, and heterogeneity was found among cell subgroups. Hence, the imbalance of various cell types affects placental activity to varying degrees, indicating the complexity of the cell networks that form the placental tissue system, and this alteration of placental function is associated with adverse events in the perinatal period.

In vitro mRNA-S maternal vaccination induced altered immune regulation at the maternal-fetal interface.

BACKGROUND: Maternal-fetal immunology is intricate, and the effects of mRNA-S maternal vaccination on immune regulation at the maternal-fetal interface require further investigation. Our study endeavors to elucidate these immunological changes, enhancing our comprehension of maternal and fetal health outcomes. By analyzing immune profiles and cytokine responses, we aim to provide valuable insights into the impact of mRNA-S vaccination on the delicate balance of immune regulation during pregnancy, addressing critical questions in the field of reproductive pharmacology. OBJECTIVES: This investigation sought to examine the prospective influence of mRNA-S-based vaccines and extracellular vesicles (EVs) containing the Spike (S) protein at the maternal-fetal interface. Our primary emphasis was on evaluating their effects on maternal decidua cells and fetal chorion trophoblast cells (hFM-CTCs). METHODS: We validated the generation of EVs containing the S protein from small human airway epithelial cell lines (HSAECs) following mRNA-S vaccine exposure. We assessed the expression of angiotensin-converting enzyme 2 (ACE2) gene and protein in fetal membranes and the placenta, with specific attention to decidual cells and fetal membrane chorion cells. To assess cellular functionality, these cells were exposed to both recombinant S protein and EVs loaded with S proteins (eSPs). RESULTS: Our findings revealed that cells and EVs subjected to mRNA-S-based vaccination exhibited altered protein expression levels of S proteins. At the feto-maternal interface, both placental and fetal membrane tissues demonstrated similar ACE-2 expression levels. Among individual cellular layers, syncytiotrophoblast cells in the placenta and chorion cells in the fetal membrane exhibited elevated ACE-2 expression. Notably, EVs derived from HSAECs activated the MAPK pathway in decidual cells. Additionally, decidual cells displayed a substantial increase in gene expression of chemokines like CXCL-10 and CXCL-11, as well as proinflammatory cytokines such as IL-6 in response to eSPs. However, the levels of Ccl-2 and IL-1ß remained unchanged in decidual cells under the same conditions. Conversely, hFM-CTCs demonstrated significant alterations in the proinflammatory cytokines and chemokines with respect to eSPs. CONCLUSION: In conclusion, our study indicates that mRNA-S-based maternal vaccination during pregnancy may influence the maternal-fetal interface's COVID-19 interaction and immune regulation. Further investigation is warranted to assess safety and implications.

IL1ß-NFκß-Myocardin signaling axis governs trophoblast-directed plasticity of vascular smooth muscle cells.

Vascular smooth muscle cell (VSMC) plasticity is fundamental in uterine spiral artery remodeling during placentation in Eutherian mammals. Our previous work showed that the invasion of trophoblast cells into uterine myometrium coincides with a phenotypic change of VSMCs. Here, we elucidate the mechanism by which trophoblast cells confer VSMC plasticity. Analysis of genetic markers on E13.5, E16.5, and E19.5 in the rat metrial gland, the entry point of uterine arteries, revealed that trophoblast invasion is associated with downregulation of MYOCARDIN, α-smooth muscle actin, and calponin1, and concomitant upregulation of Smemb in VSMCs. Myocardin overexpression or knockdown in VSMCs led to upregulation or downregulation of contractile markers, respectively. Co-culture of trophoblast cells with VSMCs decreased MYOCARDIN expression along with compromised expression of contractile markers in VSMCs. However, co-culture of trophoblast cells with VSMCs overexpressing MYOCARDIN inhibited their change in phenotype, whereas, overexpression of transactivation domain deleted MYOCARDIN failed to elicit this response. Furthermore, the co-culture of trophoblast cells with VSMCs led to the activation of NFκß signaling. Interestingly, despite producing IL-1ß, trophoblast cells possess only the decoy receptor, whereas, VSMCs possess the IL-1ß signaling receptor. Treatment of VSMCs with exogenous IL-1ß led to a decrease in MYOCARDIN and an increase in phosphorylation of NFκß. The effect of trophoblast cells in the downregulation of MYOCARDIN in VSMCs was reversed by blocking NFκß translocation to the nucleus. Together, these data highlight that trophoblast cells direct VSMC plasticity, and trophoblast-derived IL-1ß is a key player in downregulating MYOCARDIN via the NFκß signaling pathway.

Reproductive toxicity and related mechanisms of micro(nano)plastics in terrestrial mammals: Review of current evidence.

Micro(nano)plastics (MNPs) have been detected in various ecological environments and are widely used due to their stable properties, raising widespread concern about their potential human reproductive toxicity. Currently, infertility affects approximately 10-30% of couples of reproductive age globally. MNPs, as environmental pollutants, have been shown to exhibit reproductive toxicity through intrinsic mechanisms or as carriers of other hazardous substances. Numerous studies have established that MNPs of varying sizes and types can penetrate biological barriers, and enter tissues and even organelles of organisms through four main routes: dietary ingestion, inhalation, dermal contact, and medical interventions. However, historical research on the toxic effects of MNPs on reproduction mainly focused on lower and aquatic species. We conducted an inclusive review of studies involving terrestrial mammals, revealing that MNPs can induce reproductive toxicity via various mechanisms such as oxidative stress, inflammation, fibrosis, apoptosis, autophagy, disruption of intestinal flora, endocrine disruption, endoplasmic reticulum stress, and DNA damage. In terrestrial mammals, reproductive toxicity predominantly manifests as disruption in the blood-testis barrier (BTB), impaired spermatogenesis, sperm malformation, sperm DNA damage, reduced sperm fertilizing capacity, compromised oocyte maturation, impaired follicular growth, granulosa cell apoptosis, diminished ovarian reserve function, uterine and ovarian fibrosis, and endocrine disruption, among other effects. Furthermore, MNPs can traverse the maternal-fetal interface, potentially impacting offspring reproductive health. To gain a comprehensive understanding of the potential reproductive toxicity and underlying mechanisms of MNPs with different sizes, polymer types, shapes, and carried toxins, as well as to explore effective protective interventions for mitigating reproductive damage, further in-depth animal studies, clinical trials, and large-scale epidemiological studies are urgently required.

Maternal-fetal immunity and recurrent spontaneous abortion.

Recurrent Spontaneous Abortion (RSA) is a common pregnancy complication, that has multifactorial causes, and currently, 40%-50% of cases remain unexplained, referred to as Unexplained RSA (URSA). Due to the elusive etiology and mechanisms, clinical management is exceedingly challenging. In recent years, with the progress in reproductive immunology, a growing body of evidence suggests a relationship between URSA and maternal-fetal immunology, offering hope for the development of tailored treatment strategies. This article provides an immunological perspective on the pathogenesis, diagnosis, and treatment of RSA. On one hand, it comprehensively reviews the immunological mechanisms underlying RSA, including abnormalities in maternal-fetal interface immune tolerance, maternal-fetal interface immune cell function, gut microbiota-mediated immune dysregulation, and vaginal microbiota-mediated immune anomalies. On the other hand, it presents the diagnosis and existing treatment modalities for RSA. This article offers a clear knowledge framework for understanding RSA from an immunological standpoint. In conclusion, while the "layers of the veil" regarding immunological factors in RSA are gradually being unveiled, our current research may only scratch the surface. In terms of immunological etiology, effective diagnostic tools for RSA are currently lacking, and the efficacy and safety of immunotherapies, primarily based on lymphocyte immunotherapy and intravenous immunoglobulin, remain contentious.

Maternal-Fetal Compatibility in Recurrent Pregnancy Loss.

Nowadays, recurrent pregnancy loss (RPL) is an undesirable condition suffered by many patients of reproductive age. In this scenario, certain immune cell populations and molecules, involved in maternal-fetal compatibility, have emerged as factors related with the pathogenesis of RPL. Among them, uterine Natural Killer cells (uNKs) appear to be of great relevance. These cells are involved in numerous processes during pregnancy, such as the remodeling of uterine spiral arteries or the control of trophoblast invasion. These functions are regulated by the interactions that these cells establish with the extravillous trophoblast, mainly through their Killer Immunoglobulin-like Receptors (KIRs) and the Human Leukocyte Antigen-C (HLA-C) molecules expressed by the embryo. A high level of polymorphism has been reported for both molecules involved in this interaction, with some of the possible KIR-HLA-C combinations being associated with an increased risk of RPL. However, the complexity of the maternal-fetal interface goes beyond this, as other HLA molecules also appear to be related to this reproductive pathology. In this review, we will discuss the role of uNKs in pregnancy, as well as the polymorphisms and clinical implications of KIR-HLA-C binding. We will also address the involvement of other, different HLA molecules in RPL, and the current advice on the appropriate management of patients with 'immunological mismatch', thus covering the main aspects regarding the involvement of maternal-fetal compatibility in RPL.

BMP4 in Human Endometrial Stromal Cells Can Affect Decidualization by Regulating FOXO1 Expression.

CONTEXT: Recurrent spontaneous abortion (RSA) is defined as the loss of 2 or more consecutive intrauterine pregnancies with the same sexual partner in the first trimester. Despite its significance, the etiology and underlying mechanisms of RSA remain elusive. Defective decidualization is proposed as one of the potential causes of RSA, with abnormal decidualization leading to disturbances in trophoblast invasion function. OBJECTIVE: To assess the role of bone morphogenetic protein 4 (BMP4) in decidualization and RSA. METHODS: Decidual samples were collected from both RSA patients and healthy controls to assess BMP4 expression. In vitro cell experiments utilized the hESC cell line to investigate the impact of BMP4 on decidualization and associated aging, as well as its role in the maternal-fetal interface communication. Subsequently, a spontaneous abortion mouse model was established to evaluate embryo resorption rates and BMP4 expression levels. RESULTS: Our study identified a significant downregulation of BMP4 expression in the decidua of RSA patients compared to the normal control group. In vitro, BMP4 knockdown resulted in inadequate decidualization and inhibited associated aging processes. Mechanistically, BMP4 was implicated in the regulation of FOXO1 expression, thereby influencing decidualization and aging. Furthermore, loss of BMP4 hindered trophoblast migration and invasion via FOXO1 modulation. Additionally, BMP4 downregulation was observed in RSA mice. CONCLUSION: Our findings highlighted the downregulation of BMP4 in both RSA patients and mice. BMP4 in human endometrial stromal cells was shown to modulate decidualization by regulating FOXO1 expression. Loss of BMP4 may contribute to the pathogenesis of RSA, suggesting potential avenues for abortion prevention strategies.

Collateral Damage in the Placenta during Viral Infection in Pregnancy: A Possible Mechanism for Vertical Transmission and an Adverse Pregnancy Outcome.

In mammals, the placenta is a connection between a mother and a new developing organism. This tissue has a protective function against some microorganisms, transports nutrients, and exchanges gases and excretory substances between the mother and the fetus. Placental tissue is mainly composed of chorionic villi functional units called trophoblasts (cytotrophoblasts, the syncytiotrophoblast, and extravillous trophoblasts). However, some viruses have developed mechanisms that help them invade the placenta, causing various conditions such as necrosis, poor perfusion, and membrane rupture which, in turn, can impact the development of the fetus and put the mother's health at risk. In this study, we collected the most relevant information about viral infection during pregnancy which can affect both the mother and the fetus, leading to an increase in the probability of vertical transmission. Knowing these mechanisms could be relevant for new research in the maternal-fetal context and may provide options for new therapeutic targets and biomarkers in fetal prognosis.

Isolation and Immunophenotyping of Leukocytes from the Human Maternal-Fetal Interface.

During human pregnancy, leukocytes that infiltrate the maternal-fetal interface play a major role in establishing a delicate balance between immune tolerance and functional response and setting the inflammatory process that leads to labor. Here we describe two methods for isolating immune cells from the chorioamniotic membranes (decidua parietalis) and placental blood (decidua basalis) that combine gentle enzymatic digestion, magnetic cell sorting, and density gradient. Isolated leukocytes can be immunophenotypified by flow cytometry, and both isolation methods are compatible with downstream cellular and molecular applications, such as cell culture, transcriptome, and proteome analyses.

Culture and Maintenance of Immune Cells to Model Innate Immune Status at the Feto-maternal Interface.

The inflammatory process leading to human labor is mostly facilitated by immune cells, which can be studied by isolating and characterizing primary immune cells from the feto-maternal interface. However, difficulty and inconsistency in sampling approaches of immune cells and short lifespan in vitro prevent their usage in mechanistic studies to understand the maternal-fetal immunobiology. To address these limitations, existing cell line models can be differentiated into immune-like cells for use in reproductive biology experiments. In this chapter, we discussed cell culture methods of maintaining and differentiating HL-60, THP-1, and NK-92 cells to obtain neutrophil-like, macrophage-like, and decidual natural killer-like cells, respectively, which can then be used together with intrauterine cells to elucidate and investigate immune mechanisms that contribute to parturition.

The role of the annexin A protein family at the maternal-fetal interface.

Successful pregnancy requires the tolerance of the maternal immune system for the semi-allogeneic embryo, as well as a synchrony between the receptive endometrium and the competent embryo. The annexin family belongs to calcium-regulated phospholipid-binding protein, which functions as a membrane skeleton to stabilize the lipid bilayer and participate in various biological processes in humans. There is an abundance of the annexin family at the maternal-fetal interface, and it exerts a crucial role in embryo implantation and the subsequent development of the placenta. Altered expression of the annexin family and dysfunction of annexin proteins or polymorphisms of the ANXA gene are involved in a range of pregnancy complications. In this review, we summarize the current knowledge of the annexin A protein family at the maternal-fetal interface and its association with female reproductive disorders, suggesting the use of ANXA as the potential therapeutic target in the clinical diagnosis and treatment of pregnancy complications.

Mechanisms of YAP1-mediated trophoblast ferroptosis in recurrent pregnancy loss.

PURPOSE: The purpose of our study is to investigate the function of YAP1 in the trophoblast ferroptosis and maternal-fetal interface communication of RPL. METHODS: We collected 25 villous tissues and detected the expression of YAP1. Cell counting kit-8 assay, scratch wound-healing assay, and Matrigel invasion assay were performed to observe the proliferation, migration, and invasion of HTR-8/SVneo and JAR cells. Subsequently, measured the levels of reactive oxygen species (ROS), malondialdehyde (MDA), reduced glutathione (GSH), SLC7A11, SOD2, and GPX4. Ultimately, the use of ferroptosis activator (erastin) and inhibitor (Ferrostatin-1, fer-1) further confirmed the regulation by YAP1. In addition, established an in vitro-induced cell model to study the effect of YAP1 on the decidualization process. Finally, animal models were implemented for further confirmation. RESULTS: We found that YAP1 was downregulated in RPL patients. Overexpression of YAP1 could significantly enhance the proliferation, migration, and invasion of trophoblasts, and inhibit ferroptosis. Knocking down YAP1 exhibited the opposite effect. Rescue experiments have shown that YAP1 could upregulate the expression of SLC7A11 and GPX4, which are key molecules in the classic pathway of ferroptosis. In addition, the decidualization was impaired when hESCs were treated with conditioned medium of YAP1 knockdown trophoblasts. Moreover, we found that Yap1, Slc7a11, and Gpx4 were downregulated in the RPL mice, along with increased MDA and decreased GSH. CONCLUSION: Downregulation of YAP1 induces ferroptosis, thereby damaging the trophoblast invasion processes, which also disturbs the communication at the maternal-fetal interface. Our study identified YAP1 as a potential key molecule in the pathogenesis of RPL.

Progesterone-mediated remodeling of the maternal-fetal interface by a PGRMC1-dependent mechanism.

Implantation and maintenance of pregnancy involve intricate immunological processes that enable the developing fetus to coexist with the maternal immune system. Progesterone, a critical hormone during pregnancy, is known to promote immune tolerance and prevent preterm labor. However, the mechanism by which progesterone mediates these effects remains unclear. In this study, we investigated the role of the non-classical progesterone receptor membrane component 1 (PGRMC1) in progesterone signaling at the maternal-fetal interface. Using JEG3 cells, a trophoblast model cell line, we observed that progesterone stimulation increased the expression of human leukocyte antigen-C (HLA-C) and HLA-G, key molecules involved in immune tolerance. We also found that progesterone upregulated the expression of the transcription factor ELF3, which is known to regulate trophoblast-specific HLA-C expression. Interestingly, JEG3 cells lacked expression of classical progesterone receptors (PRs) but exhibited high expression of PGRMC1, a finding we confirmed in primary trophoblasts by mining sc-RNA seq data from human placenta. To investigate the role of PGRMC1 in progesterone signaling, we used CRISPR/Cas9 technology to knockout PGRMC1 in JEG3 cells. PGRMC1-deficient cells showed a diminished response to progesterone stimulation. Furthermore, we found that the progesterone antagonist RU486 inhibited ELF3 expression in a PGRMC1-dependent manner, suggesting that RU486 acts as a progesterone antagonist by competing for receptor binding. Additionally, we found that RU486 inhibited cell invasion, an important process for successful pregnancy, and this inhibitory effect was dependent on PGRMC1. Our findings highlight the crucial role of PGRMC1 in mediating the immunoregulatory effects of progesterone at the maternal-fetal interface.

Dysregulation of mucosal-associated invariant T cells correlates with altered placental microenvironment in preterm birth.

Preterm birth (PTB) is a major problem affecting perinatal health, directly increasing the mortality risk of mother and infant that often results from the breakdown of the maternal-fetal immune balance. Increasing evidence shows the essential role of mucosal-associated invariant T (MAIT) cells to balance antibacterial function and immune tolerance function during pregnancy. However, the phenotype and function of placental MAIT cells and their specific mechanisms in PTB remain unclear. Here, we report that MAIT cells in placentas from PTBs show increased activation levels and decreased IFN-γ secretion capacity compared with those from normal pregnancies. Moreover, our data indicate gravidity is a factor affecting placental MAIT cells during pregnancies. Multi-omics analysis indicated aberrant immune activation and abnormal increase of lipids and lipid-like metabolites in the PTB placental microenvironment. Moreover, the proportion and activation of MAIT cells were positively correlated with the abnormal increase of lipids and lipid-like metabolites. Together, our work revealed that abnormal activation and impaired function of MAIT cells may be related to abnormal elevation of lipids and lipid-like metabolites in PTB.

MiR-142-3p Regulates ILC1s by Targeting HMGB1 via the NF-κB Pathway in a Mouse Model of Early Pregnancy Loss.

OBJECTIVE: Innate lymphoid cells (ILCs) are a class of newly discovered immunocytes. Group 1 ILCs (ILC1s) are identified in the decidua of humans and mice. High mobility group box 1 (HMGB1) is predicted to be one of the target genes of miR-142-3p, which is closely related to pregnancy-related diseases. Furthermore, miR-142-3p and HMGB1 are involved in regulating the NF-κB signaling pathway. This study aimed to examine the regulatory effect of miR-142-3p on ILC1s and the underlying mechanism involving HMGB1 and the NF-κB signaling pathway. METHODS: Mouse models of normal pregnancy and abortion were constructed, and the alterations of ILC1s, miR-142-3p, ILC1 transcription factor (T-bet), and pro-inflammatory cytokines of ILC1s (TNF-α, IFN-γ and IL-2) were detected in mice from different groups. The targeting regulation of HMGB1 by miR-142-3p in ILC1s, and the expression of HMGB1 in normal pregnant mice and abortive mice were investigated. In addition, the regulatory effects of miR-142-3p and HMGB1 on ILC1s were detected in vitro by CCK-8, Annexin-V/PI, ELISA, and RT-PCR, respectively. Furthermore, changes of the NF-κB signaling pathway in ILC1s were examined in the different groups. For the in vivo studies, miR-142-3p-Agomir was injected in the uterus of abortive mice to evaluate the abortion rate and alterations of ILC1s at the maternal-fetal interface, and further detect the expression of HMGB1, pro-inflammatory cytokines, and the NF-κB signaling pathway. RESULTS: The number of ILC1s was significantly increased, the level of HMGB1 was significantly upregulated, and that of miR-142-3p was considerably downregulated in the abortive mice as compared with the normal pregnant mice (all P<0.05). In addition, miR-142-3p was found to drastically inhibit the activation of the NF-κB signaling pathway (P<0.05). The number of ILC1s and the levels of pro-inflammatory cytokines were significantly downregulated and the activation of the NF-κB signaling pathway was inhibited in the miR-142-3p Agomir group (all P<0.05). CONCLUSION: miR-142-3p can regulate ILC1s by targeting HMGB1 via the NF-κB signaling pathway, and attenuate the inflammation at the maternal-fetal interface in abortive mice.

Decidual-tissue-resident memory T cells protect against nonprimary human cytomegalovirus infection at the maternal-fetal interface.

Congenital cytomegalovirus (cCMV) is the most common intrauterine infection, leading to infant neurodevelopmental disabilities. An improved knowledge of correlates of protection against cCMV is needed to guide prevention strategies. Here, we employ an ex vivo model of human CMV (HCMV) infection in decidual tissues of women with and without preconception immunity against CMV, recapitulating nonprimary vs. primary infection at the authentic maternofetal transmission site. We show that decidual tissues of women with preconception immunity against CMV exhibit intrinsic resistance to HCMV, mounting a rapid activation of tissue-resident memory CD8+ and CD4+ T cells upon HCMV reinfection. We further reveal the role of HCMV-specific decidual-tissue-resident CD8+ T cells in local protection against nonprimary HCMV infection. The findings could inform the development of a vaccine against cCMV and provide insights for further studies of the integrity of immune defense against HCMV and other pathogens at the human maternal-fetal interface.

Novel Insights into Prokineticin 1 Role in Pregnancy-related Diseases.

Prokineticin 1 (PROK1) is a secreted protein involved in a range of physiological activities such as cell proliferation, migration, angiogenesis, and neuronal cell proliferation. Emerging evidences show that PROK1/PROK receptors (PROKRs) are expressed by trophoblasts, and decidual stroma cells at the maternal-fetal interface. PROK1 plays a critical role in successful pregnancy establishment by regulating the decidualization, implantation and placental development. Dysregulation of prokineticin signaling has been described in certain pathological states associated with pregnancy, including pre-eclampsia, recurrent miscarriage and fetal growth restriction. In this review, the expression and pleiotropic roles of PROK1 under physiological and pathological pregnancy conditions are discussed.

An investigation of the distributions of ferroptosis and necroptosis mediators in the maternal-fetal interface at different days of rat pregnancy.

Ferroptosis and necroptosis are recognized as playing major roles in the regulation of various physiological processes. However, the physiological role of the cell death mediated by these two pathways in the developmental process has not yet been clearly established. This study investigated ferroptosis and necroptosis signalling pathways in maternal-fetal tissue in the different gestational days (GD) of rat pregnancy using immunohistochemical and western blot methods in order to fill this gap. Twenty-four female Wistar albino rats were mated and divided into three groups. Maternal-fetal tissue samples were collected on GD 5, 12 and 19 of pregnancy. Expression and total protein levels of the markers glutathione peroxidase-4, soluble transporter family 7 member 11, transferrin receptor, receptor-interacting serine/threonine-protein kinase 1, receptor-interacting serine/threonine-protein kinase 3 and mixed lineage kinase domain-like protein were investigated on both the maternal and fetal surfaces of the placenta using immunohistochemical and western blot methods. The results showed varying levels of protein expression of both ferroptosis and necroptosis mediators in the GD 5, 12 and 19 of pregnancy. Immunohistochemical analyses revealed that these mediators were located on both the maternal (decidua and metrial gland) and fetal surfaces (labyrinth zone, yolk sac and basal zone) and that their expression levels changed in the different GD. The findings revealed the existence of important ferroptosis and necroptosis pathway mediators in rat maternal-fetal tissue. These results may provide a molecular framework for a better understanding of the communication between the placenta, decidua and fetus during the developmental process.