Placental fetal macrophages (fMacs) are the only immune cells on the fetal side of the placental barrier. Mouse models have not been used to test their function because they have previously been found to have distinct cellular origins and functions in mice and humans. Here, we test the ontogeny of mouse placental fMacs. Using a new Hoxa13Cre allele that labels all placental endothelial cells (ECs), we demonstrate that mouse placenta fMacs do not arise from placental endothelium. Instead, lineage tracing studies using Tie2-Cre and Cx3cr1CreERT2 alleles demonstrate that mouse placental fMacs arise from yolk sac endothelium. Administration of blocking antibodies against CSF1R at E6.5 and E7.5 results in depletion of placental fMacs throughout pregnancy, and this suggests a yolk sac origin, similar to that in human fMacs. This Matters Arising paper is in response to Liang et al., published in Developmental Cell. A response by Liang and Liu is published in this issue.

The intervillous space of the placenta is a part of the fetal-maternal interface, where maternal blood enters to provide nutrients and gas exchange. Little is known about the maternal immune cells at this site, which are in direct contact with fetal tissues. We have characterized the T cell composition and chemokine profile in paired intervillous and peripheral blood samples from healthy mothers giving birth following term pregnancies. Mucosal-associated invariant T (MAIT) cells and effector memory (EM) T cells were enriched in the intervillous blood compared to peripheral blood, suggesting that MAIT cells and other EM T cells home to the placenta during pregnancy. Furthermore, pregnant women had lower proportions of peripheral blood MAIT cells compared to non-pregnant women. The levels of several chemokines were significantly higher in intervillous compared to peripheral blood, including macrophage migration inhibitory factor (MIF), CXCL10, and CCL25, whereas CCL21, CCL27 and CXCL12 were lower. Migration assays showed that MAIT cells and EM T cells migrated toward conditioned medium from placental explants. A multivariate factor analysis indicated that high levels of MIF and CCL25 were associated with high proportions of MAIT cells in intervillous blood. Blocking of MIF or a combination of MIF, CCL25, and CCL20 in migration assays inhibited MAIT cell migration toward placenta conditioned medium. Finally, MAIT cells showed migratory capacities toward recombinant MIF. Together, these findings indicate that term placental tissues attract MAIT cells, and that this effect is at least partly mediated by MIF.

Cellular differentiation and lineage commitment are considered to be robust and irreversible processes during development. Recent work has shown that mouse and human fibroblasts can be reprogrammed to a pluripotent state with a combination of four transcription factors. We hypothesized that combinatorial expression of chondrocyte-specific transcription factors could directly convert human placental cells into chondrocytes. Starting from a pool of candidate genes, we identified a combination of only five genes (5F pool)-BCL6, T (also called BRACHYURY), c-MYC, MITF, and BAF60C (also called SMARCD3)-that rapidly and efficiently convert postnatal human chorion and decidual cells into chondrocytes. The cells generated expressed multiple cartilage-specific genes, such as Collagen type II α1, LINK PROTEIN-1, and AGGRECAN, and exhibited characteristics of cartilage both in vivo and in vitro. Expression of the endogenous genes for T and MITF was initiated, implying that the cell conversion is due to not only the forced expression of the transgenes, but also to cellular reprogramming by the transgenes. This direct conversion system from noncartilage tissue to cartilaginous tissue is a substantial advance toward understanding cartilage development, cell-based therapy, and oncogenesis of chondrocytes.

Human placenta is used to make the medicinal product Placenta Hominis in Asian countries. With its therapeutic benefits and limited supply, intentional or inadvertent adulteration is found in the market. In order to enforce the implementation of product description laws and protect customer rights, we established a hierarchical protocol involving morphological, chemical, biochemical and molecular diagnosis to authenticate this medicinal product.

To evaluate the efficacy and safety of prophylactic balloon occlusion of the infrarenal abdominal aorta in pernicious placenta previa coexisting with placenta accrete.

The success of pregnancy depends on the maternal immune system's ability to promote tolerance and host defense. This equilibrium is compromised in inflammatory and infectious impairment of placenta. Smoking during pregnancy exposes the fetus to severe complications which might result from an alteration in placenta macrophages (pMφ) functions. In this study, we assessed the effect of cigarette smoke extract (CSE) on the functions of third trimester pMφs.CSE inhibited particles uptake and the formation of multinucleated giant cells, a recently reported property of pMφs based on their ability to fuse in vitro. These alterations were associated with a CSE-induced abnormal activation of pMφs, which was characterized by an increased release of TNF, interleukin (IL)-33, and decreased IL-6 and IL-10 release. Furthermore, CSE enhanced the expression of metalloproteinase genes known to be involved in tissue remodeling. This effect of CSE on pMφs was specific because CSE affected circulating monocytes in a different way. Finally, we showed that nicotine affected in part the functional properties of pMφs. Taken together, these results showed that CSE modulated the functional activity of pMφs, which may compromise pregnancy.

Recent studies have suggested that bacteria associated with the placenta-a "placental microbiome"-may be important in reproductive health and disease. However, a challenge in working with specimens with low bacterial biomass, such as placental samples, is that some or all of the bacterial DNA may derive from contamination in dust or commercial reagents. To investigate this, we compared placental samples from healthy deliveries to a matched set of contamination controls, as well as to oral and vaginal samples from the same women.

To develop the risk prediction model of intraoperative massive blood loss in placenta previa with placenta increta or percreta.

The placenta is composed of two lineages: the trophoblast and mesoderm. While morphological assessment of the placenta has highlighted major cell types and developmental structures, the human placenta is relatively unexplained on a molecular level. Current molecular analysis of the placenta has largely been confined to assessing whole organs that include both cell lineages and their differentiated progeny. This has confounded our understanding of the processes of placental development and function for two reasons. First, it is difficult to delineate the specific molecular contribution from each tissue layer or cell type. Second, it is challenging to determine if gene expression influenced by development or pathology reflect changes in all cells or subsets of cells. Applications of classic techniques for single cell analysis are now being combined with emerging technologies in high throughput analysis, such as sequencing and antibody production and screening. These combinations are leading to a new powerful paradigm for developmental and pathological research. In this review we describe techniques in cellular analysis of tissues and their application to investigation of the development of the placenta and trophoblast. Additionally we review and consider how these approaches may aid the search for stable primary cultures of human trophoblast stem cells and progenitors.

The human placenta is a particular organ that inseparably binds the mother and the fetus. The proper development and survival of the conceptus relies on the essential interplay between maternal and fetal factors involved in cooperation within the placenta. In our study, high-throughput sequencing (RNA-seq) was applied to analyze the global transcriptome of the human placenta during uncomplicated pregnancies. The RNA-seq was utilized to identify the global pattern of the gene expression in placentas (N = 4) from women in single and twin pregnancies. During analyses, we obtained 228,044 transcripts. More than 91% of them were multi-exon, and among them 134 were potentially unknown protein coding genes. Expression levels (FPKM) were estimated for 38,948 transcriptional active regions, and more than 3000 of genes were expressed with FPKM >20 in each sample. Additionally, all unannotated transcripts with estimated FPKM values were localized on the human genome. Highly covered splice junctions unannotated in the human genome (6497) were identified, and among them 30 were novel. To gain a better understanding of the biological implications, the assembled transcripts were annotated with gene ontology (GO) terms. Single nucleotide variants were predicted for the transcripts assigned to each analyzed GO category. Our results may be useful for establishing a general pattern of the gene expression in the human placenta. Characterizing placental transcriptome, which is crucial for a pregnancy's outcome, can serve as a basis for identifying the mechanisms underlying physiological pregnancy, as well as may be useful for an early detection of the genomic defects.

This study characterises HERV-W (syncytin 1) expression in normal and pathologic placenta and in BeWo cells. HERV-W mRNA levels were higher in the first trimester than at term, and similar patterns were observed with another retrovirally-derived mRNA species, ERV-3. N-glycosylated syncytin 1 precursor (73 kDa) is cleaved to surface-associated (SU) and transmembrane (TM) subunits. Both were evident in villous trophoblast, where perinuclear and punctate cytoplasmic deposits were observed, and linear TM subunit immunoreactivity was seen at the syncytial microvillous membrane. Punctate immunoreactivity was seen in BeWo cells with antibodies to SU and TM, and the two were co-localised. SU immunoreactivity was observed in association with fetal endothelium, and this effect was increased in tissue from pre-eclamptic placentas, which also showed a higher level of total SU protein. Absence of the TM subunit from endothelium suggests it is not a biosynthetic source. We suggest that SU is released from trophoblast into fetal circulation where it may bind vascular endothelium.

Aldehyde dehydrogenase 3B2 (ALDH3B2) gene contains a premature termination codon, which can be skipped or suppressed resulting in full-length protein expression. Alternatively, the longest putative open reading frame starting with the second in-frame start codon would encode short isoform. No unequivocal evidence of ALDH3B2 expression in healthy human tissues is available. The aim of this study was to confirm its expression in human placenta characterized by the highest ALDH3B2 mRNA abundance. ALDH3B2 DNA and mRNA were sequenced. The expression was investigated using western blot. The identity of the protein was confirmed using mass spectrometry (MS). The predicted tertiary and quaternary structures, subcellular localization, and phosphorylation sites were assessed using bioinformatic analyses. All DNA and mRNA isolates contained the premature stop codon. In western blot analyses, bands corresponding to the mass of full-length protein were detected. MS analysis led to the identification of two unique peptides, one of which is encoded by the nucleotide sequence located upstream the second start codon. Bioinformatic analyses suggest cytoplasmic localization and several phosphorylation sites. Despite premature stop codon in DNA and mRNA sequences, full-length ALDH3B2 was found. It can be formed as a result of premature stop codon readthrough, complex phenomenon enabling stop codon circumvention.

No abstract available

Cell-lines derived from human placenta and chorion have been used extensively to model the endocrine functions of human trophoblast. In general terms, the endocrine functions of the primary cells and tissues are at least partially replicated within the cell-lines, suggesting that they may be used as appropriate models. There are, however, two major provisos that compromise this generalisation. Firstly, the endocrine function of placenta represents a complex interaction between cytotrophoblast, syncytiotrophoblast and multiple regulators, so a single cell population digested from the normal environment is unlikely to represent this. Secondly, the characterisation of primary trophoblast populations and of cell-lines is incomplete, complicating the assignment of functions to trophoblast populations. Despite these difficulties, useful information has been obtained from the available cell-lines, regardless of whether they have arisen spontaneously, been transformed in vitro, or derived from cancers in vivo.

The placenta is a key component in understanding the physiological processes involved in pregnancy. Characterizing genes critical for placental function can serve as a basis for identifying mechanisms underlying both normal and pathologic pregnancies. Detailing the placental tissue transcriptome could provide a valuable resource for genomic studies related to placental disease.

Maternal obesity is associated with an increased risk of obesity and metabolic disease in offspring. Increasing evidence suggests that the placenta plays an active role in fetal programming. In this study, we used a mouse model of diet-induced obesity to demonstrate that the abnormal metabolic milieu of maternal obesity sets the stage very early in pregnancy by altering the transcriptome of placenta progenitor cells in the preimplantation (trophectoderm [TE]) and early postimplantation (ectoplacental cone [EPC]) placenta precursors, which is associated with later changes in placenta development and function. Sphingolipid metabolism was markedly altered in the plasma of obese dams very early in pregnancy as was expression of genes related to sphingolipid processing in the early placenta. Upregulation of these pathways inhibits angiogenesis and causes endothelial dysfunction. The expression of many other genes related to angiogenesis and vascular development were disrupted in the TE and EPC. Other key changes in the maternal metabolome in obese dams that are likely to influence placenta and fetal development include a marked decrease in myo and chiro-inositol. These early metabolic and gene expression changes may contribute to phenotypic changes in the placenta, as we found that exposure to a high-fat diet decreased placenta microvessel density at both mid and late gestation. This is the first study to demonstrate that maternal obesity alters the transcriptome at the earliest stages of murine placenta development.

Trophoblast inclusions (TIs) are often found in placentas of genetically abnormal gestations. Although best documented in placentas from molar pregnancies and chromosomal aneuploidy, TIs are also associated with more subtle genetic abnormalities, and possibly autism. Less than 3% of non-aneuploid, non-accreta placentas have TIs. We hypothesize that placental genetics may play a role in the development of placenta accreta and aim to study TIs as a potential surrogate indicator of abnormal placental genetics.

Tonicity-responsive enhancer binding protein (TonEBP) is a signal transcription factor of transporters such as sodium-myo-inositol cotransporter (SMIT), aldose reductase. TonEBP has a variety of functions such as control of intracellular osmolytes and immunomodulating. It is known that TonEBP is abundant in the placenta, but location and function aren't known. The aim of this study is to describe the localization of TonEBP in the placenta. We assayed the immunohistochemistry of TonEBP and performed in situ hybridization of SMIT in normal human full term placenta. In normal human full term placenta, TonEBP was in villous trophoblasts, extravillous trophoblasts and some endothelial cells. The result of the in situ hybridization of SMIT was similar to that of immunohistochemistry of TonEBP. Neither TonEBP nor SMIT was present in TonEBP knockout mouse placenta. This shows TonEBP is a key factor in SMIT transcription. TonEBP may play an important role in transporting of inositol to fetus in placenta.

To assess maternal and fetal morbidity associated with placenta previa and morbidly adherent placenta (MAP).

Kisspeptin is an essential gatekeeper of reproductive function. During pregnancy high circulating levels of kisspeptin have been described, however the clear role of this neuropeptide in pregnancy remains unknown. We tested the existence of rhythmic kisspeptin expression in human full-term placenta from healthy pregnant women at six different time points during the day. The data obtained by Western blotting were fitted to a mathematical model (Fourier series), demonstrating, for the first time, the existence of a circadian rhythm in placental kisspeptin expression.