Synergies of Extracellular Vesicles and Microchimerism in Promoting Immunotolerance During Pregnancy.

The concept of biological identity has been traditionally a central issue in immunology. The assumption that entities foreign to a specific organism should be rejected by its immune system, while self-entities do not trigger an immune response is challenged by the expanded immunotolerance observed in pregnancy. To explain this "immunological paradox", as it was first called by Sir Peter Medawar, several mechanisms have been described in the last decades. Among them, the intentional transfer and retention of small amounts of cells between a mother and her child have gained back attention. These microchimeric cells contribute to expanding allotolerance in both organisms and enhancing genetic fitness, but they could also provoke aberrant alloimmune activation. Understanding the mechanisms used by microchimeric cells to exert their function in pregnancy has proven to be challenging as per definition they are extremely rare. Profiting from studies in the field of transplantation and cancer research, a synergistic effect of microchimerism and cellular communication based on the secretion of extracellular vesicles (EVs) has begun to be unveiled. EVs are already known to play a pivotal role in feto-maternal tolerance by transferring cargo from fetal to maternal immune cells to reshape their function. A further aspect of EVs is their function in antigen presentation either directly or on the surface of recipient cells. Here, we review the current understanding of microchimerism in the feto-maternal tolerance during human pregnancy and the potential role of EVs in mediating the allorecognition and tropism of microchimeric cells.

Smoking for two- effects of tobacco consumption on placenta.

Tobacco smoking is an important public health issue recognized by the world health organization as one of the most serious, preventable risk factors for developing a series of pregnancy pathologies. Maternal smoking is positively associated with intrauterine growth restriction (IUGR) and gestational diabetes (GDM), but negatively associated with preeclampsia (PE). In this review, we examine epidemiological, clinical and laboratory studies of smoking effects on immunoregulation during pregnancy, trophoblast function, and placental vasculature development and metabolism. We aim to identify effects of tobacco smoke components on specific placental compartments or cells, which may contribute to the understanding of the influences of maternal smoking on placenta function in normal and pathological pregnancies. Data corroborates that in any trimester, smoking is unsafe for pregnancy and that its detrimental effects outweigh questionable benefits. The effects of maternal smoking on the maternal immune regulation throughout pregnancy and the impact of different tobacco products on fetal growth have not yet been fully understood. Smoking cessation rather than treatment with replacement therapies is recommended for future mothers because also single components of tobacco and its smoke may have detrimental effects on placental function.

Pregnancy and pandemics: Interaction of viral surface proteins and placenta cells.

Throughout history, pandemics of infectious diseases caused by emerging viruses have spread worldwide. Evidence from previous outbreaks demonstrated that pregnant women are at high risk of contracting the diseases and suffering from adverse outcomes. However, while some viruses can cause major health complications for the mother and her fetus, others do not appear to affect pregnancy. Viral surface proteins bind to specific receptors on the cellular membrane of host cells and begin therewith the infection process. During pregnancy, the molecular features of these proteins may determine specific target cells in the placenta, which may explain the different outcomes. In this review, we display information on Variola, Influenza, Zika and Corona viruses focused on their surface proteins, effects on pregnancy, and possible target placental cells. This will contribute to understanding viral entry during pregnancy, as well as to develop strategies to decrease the incidence of obstetrical problems in current and future infections.

Molecular characteristics of established trophoblast-derived cell lines.

INTRODUCTION: Research on human placental development and function lacks a conclusive in vivo model. To investigate the intracellular molecular mechanisms in trophoblast cells, different cell lines have been established during the last decades. So far, none of these accomplishes all features of primary trophoblast, thus their suitability as well as the transferability of the results has been discussed. The aim of this study is to assess molecular markers and features matching different trophoblast subpopulations in trophoblastic cell lines to provide orientation on their suitability and relevance for distinct research questions. METHODS: The commonly used trophoblastic cell lines, BeWo, JEG-3, HTR-8/SVneo, AC1-M59, AC1-M32, ACH-3P and Swan71 were selected. qPCR and immunoblotting were used to determine expression of characteristic molecular markers. C14MC, C19MC and miR-371-3 miRNA expression were investigated by real time PCR. Proliferation, migration and network stabilization assays were performed. Hormone secretion was determined by chemiluminescent-immunoassays. DNA profiles were obtained by Short Tandem Repeat (STR)-genotyping. RESULTS: Immortalized cell lines differ from choriocarcinoma-derived ones in the expression of HLA-G, E-cadherin, N-cadherin, VE-cadherin, cadherin-11, cytokeratin 7, vimentin, ADAM12 and PRG2. Compared to choriocarcinoma-derived cell lines, expression of C19MC and hormone secretion were almost absent in immortalized cell lines. Conversely, they express C14MC and exhibit higher migration and network stabilization. DISCUSSION: The data presented will help justify the use of a cell line to evaluate distinct features of trophoblast biology and pathology. In general, characteristics and markers of choriocarcinoma derived cell lines seem to be more similar to in vivo trophoblast than immortalized cell lines and thus might be regarded as more suitable models.

Epithelial Membrane Protein 2 Suppresses Non-Small Cell Lung Cancer Cell Growth by Inhibition of MAPK Pathway.

Epithelial membrane proteins (EMP1-3) are involved in epithelial differentiation and carcinogenesis. Dysregulated expression of EMP2 was observed in various cancers, but its role in human lung cancer is not yet clarified. In this study, we analyzed the expression of EMP1-3 and investigated the biological function of EMP2 in non-small cell lung cancer (NSCLC). The results showed that lower expression of EMP1 was significantly correlated with tumor size in primary lung tumors (p = 0.004). Overexpression of EMP2 suppressed tumor cell growth, migration, and invasion, resulting in a G1 cell cycle arrest, with knockdown of EMP2 leading to enhanced cell migration, related to MAPK pathway alterations and disruption of cell cycle regulatory genes. Exosomes isolated from transfected cells were taken up by tumor cells, carrying EMP2-downregulated microRNAs (miRNAs) which participated in regulation of the tumor microenvironment. Our data suggest that decreased EMP1 expression is significantly related to increased tumor size in NSCLC. EMP2 suppresses NSCLC cell growth mainly by inhibiting the MAPK pathway. EMP2 might further affect the tumor microenvironment by regulating tumor microenvironment-associated miRNAs.

MiR-519d-3p in Trophoblastic Cells: Effects, Targets and Transfer to Allogeneic Immune Cells via Extracellular Vesicles.

Members of the placenta-specific miRNA cluster C19MC, including miR-519d, are secreted by fetal trophoblast cells within extracellular vesicles (EVs). Trophoblast-derived EVs can be internalized by the autologous trophoblast and surrounding maternal immune cells, resulting in coordination of cellular responses. The study of functions and targets of placental miRNAs in the donor and recipient cells may contribute to the understanding of the immune tolerance essential in pregnancy. Here, we report that miR-519d-3p levels correlate positively with cell proliferation and negatively with migration in trophoblastic cell lines. Inhibition of miR-519d-3p in JEG-3 cells increases caspase-3 activation and apoptosis. PDCD4 and PTEN are targeted by miR-519d-3p in a cell type-specific manner. Transfection of trophoblastic cell lines with miR-519d mimic results in secretion of EVs containing elevated levels of this miRNA (EVmiR-519d). Autologous cells enhance their proliferation and decrease their migration ability when treated with EVmiR-519d. NK92 cells incorporate EV-delivered miR-519d-3p at higher levels than Jurkat T cells. EVmiR-519d increases the proliferation of Jurkat T cells but decreases that of NK92 cells. Altogether, miR-519d-3p regulates pivotal trophoblast cell functions, can be transferred horizontally via EVs to maternal immune cells and exerts functions therein. Vesicular miRNA transfer from fetal trophoblasts to maternal immune cells may contribute to the immune tolerance in pregnancy.

Role of IL-36 Cytokines in the Regulation of Angiogenesis Potential of Trophoblast Cells.

IL-36 cytokines (the agonists IL-36α, IL-36ß, IL-36γ, and the antagonist IL-36Ra) are expressed in the mouse uterus and associated with maternal immune response during pregnancy. Here, we characterize the expression of IL-36 members in human primary trophoblast cells (PTC) and trophoblastic cell lines (HTR-8/SVneo and JEG-3) and upon treatment with bacterial and viral components. Effects of recombinant IL-36 on the migration capacity of trophoblastic cells, their ability to interact with endothelial cells and the induction of angiogenic factors and miRNAs (angiomiRNAs) were examined. Constitutive protein expression of IL-36 (α, ß, and γ) and their receptor (IL-36R) was found in all cell types. In PTC, transcripts for all IL-36 subtypes were found, whereas in trophoblastic cell lines only for IL36G and IL36RN. A synthetic analog of double-stranded RNA (poly I:C) and lipopolysaccharide (LPS) induced the expression of IL-36 members in a cell-specific and time-dependent manner. In HTR-8/SVneo cells, IL-36 cytokines increased cell migration and their capacity to interact with endothelial cells. VEGFA and PGF mRNA and protein, as well as the angiomiRNAs miR-146a-3p and miR-141-5p were upregulated as IL-36 response in PTC and HTR-8/SVneo cells. In conclusion, IL-36 cytokines are modulated by microbial components and regulate trophoblast migration and interaction with endothelial cells. Therefore, a fundamental role of these cytokines in the placentation process and in response to infections may be expected.