The placenta: a multifaceted, transient organ

Fluoride-related changes in the fetal cord blood proteome; a pilot study

BACKGROUND

Fluoride exposure during pregnancy has been associated with various effects on offspring, including changes in behavior and IQ. To provide clues to possible mechanisms by which fluoride may affect human fetal development, we completed proteomic analyses of cord blood serum collected from second-trimester pregnant women residing in northern California, USA.

OBJECTIVE

To identify changes in cord blood proteins associated with maternal serum fluoride concentration in pregnant women.

METHODS

The proteomes of 19 archived second-trimester cord blood samples from women living in northern California, USA, and having varied serum fluoride concentrations, were analyzed by quantitative mass spectrometry. The 327 proteins that were quantified were characterized by their abundance relative to maternal serum fluoride concentration, and subjected to pathway analyses using PANTHER and Ingenuity Pathway Analysis processes.

RESULTS

Pathway analyses showed significant increases in process related to reactive oxygen species and cellular oxidant detoxification, associated with increasing maternal serum fluoride concentrations. Pathways showing significant decreases included complement cascade, suggesting alterations in alterations in process associated with inflammation.

CONCLUSION

Maternal fluoride exposure, as measured by serum fluoride concentrations in a small, but representative sample of women from northern California, USA, showed significant changes in the second trimester cord blood proteome relative to maternal serum fluoride concentration.

Modeling the human placenta: in vitro applications in developmental and reproductive toxicology

During its temporary tenure, the placenta has extensive and specialized functions that are critical for pre- and post-natal development. The consequences of chemical exposure in utero can have profound effects on the structure and function of pregnancy-associated tissues and the life-long health of the birthing person and their offspring. However, the toxicological importance and critical functions of the placenta to embryonic and fetal development and maturation have been understudied. This narrative will review early placental development in humans and highlight some in vitro models currently in use that are or can be applied to better understand placental processes underlying developmental toxicity due to in utero environmental exposures.

METTL3 shapes m6A epitranscriptomic landscape for successful human placentation

Methyltransferase-like 3 (METTL3), the catalytic enzyme of methyltransferase complex for m6A methylation of RNA, is essential for mammalian development. However, the importance of METTL3 in human placentation remains largely unexplored. Here, we show that a fine balance of METTL3 function in trophoblast cells is essential for successful human placentation. Both loss-of and gain-in METTL3 functions are associated with adverse human pregnancies. A subset of recurrent pregnancy losses and preterm pregnancies are often associated with loss of METTL3 expression in trophoblast progenitors. In contrast, METTL3 is induced in pregnancies associated with fetal growth restriction (FGR). Our loss of function analyses showed that METTL3 is essential for the maintenance of human TSC self-renewal and their differentiation to extravillous trophoblast cells (EVTs). In contrast, loss of METTL3 in human TSCs promotes syncytiotrophoblast (STB) development. Global analyses of RNA m6A modification and METTL3-RNA interaction in human TSCs showed that METTL3 regulates m6A modifications on the mRNA molecules of critical trophoblast regulators, including GATA2, GATA3, TEAD1, TEAD4, WWTR1, YAP1, TFAP2C and ASCL2 , and loss of METTL3 leads to depletion of mRNA molecules of these critical regulators. Importantly, conditional deletion of Mettl3 in trophoblast progenitors of an early post-implantation mouse embryo also leads to arrested self-renewal. Hence, our findings indicate that METLL3 is a conserved epitranscriptomic governor in trophoblast progenitors and ensures successful placentation by regulating their self-renewal and dictating their differentiation fate.

Kisspeptin expression levels in patients with placenta previa: A randomized trial

BACKGROUND

This study aimed to explore the potential influence of kisspeptin (KISS1) levels on the etiology of placenta previa for early pregnancy diagnosis.

METHODS

The study included 20 pregnant women diagnosed with placenta previa and 20 pregnant woman with normal pregnancies between 2021 and 2022. Plasma KISS1 levels were determined through biochemical analysis, while genetic analysis assessed KISS1 and KISS1 receptor gene expression levels. Immunohistochemical methods were employed to determine placenta KISS1 levels.

RESULTS

The evaluation of KISS1 concentration in serum revealed a significant decrease in the placenta previa group compared to the control group (P < .001). KISS1 gene expression level 0.043-fold decreased in the placenta previa group (P < .001). Furthermore, the KISS1 receptor gene expression level increased 170-fold in the placenta previa group.

CONCLUSIONS

Results from biochemical, immunohistochemical, and genetic analyses consistently indicated significantly reduced KISS1 expression in patients with placenta previa. These findings suggest a potential link between diminished KISS1 levels and the occurrence of placenta previa. KISS1 may play a critical role in the etiology of placenta previa. Detailed studies on angiogenesis, cell migration and tissue modeling should be conducted to understand possible mechanisms.

TFEB safeguards trophoblast syncytialization in humans and mice

Nutrient sensing and adaptation in the placenta are essential for pregnancy viability and proper fetal growth. Our recent study demonstrated that the placenta adapts to nutrient insufficiency through mechanistic target of rapamycin (mTOR) inhibition-mediated trophoblast differentiation toward syncytiotrophoblasts (STBs), a highly specialized multinucleated trophoblast subtype mediating extensive maternal-fetal interactions. However, the underlying mechanism remains elusive. Here, we unravel the indispensable role of the mTORC1 downstream transcriptional factor TFEB in STB formation both in vitro and in vivo. TFEB deficiency significantly impaired STB differentiation in human trophoblasts and placenta organoids. Consistently, systemic or trophoblast-specific deletion of Tfeb compromised STB formation and placental vascular construction, leading to severe embryonic lethality. Mechanistically, TFEB conferred direct transcriptional activation of the fusogen ERVFRD-1 in human trophoblasts and thereby promoted STB formation, independent of its canonical function as a master regulator of the autophagy-lysosomal pathway. Moreover, we demonstrated that TFEB directed the trophoblast syncytialization response driven by mTOR complex 1 (mTORC1) signaling. TFEB expression positively correlated with the reinforced trophoblast syncytialization in human fetal growth-restricted placentas exhibiting suppressed mTORC1 activity. Our findings substantiate that the TFEB-fusogen axis ensures proper STB formation during placenta development and under nutrient stress, shedding light on TFEB as a mechanistic link between nutrient-sensing machinery and trophoblast differentiation.

Effects of individual drug and combination antiretroviral therapy on trophoblast proliferation

BACKGROUND

Combination antiretroviral therapy (cART) has been reported to reduce perinatal transmission of human immunodeficiency virus (HIV) and improve maternal survival outcomes. Recent studies have associated in-utero exposure to cART drugs with adverse outcomes such as pre-eclampsia, preterm delivery, low birth weight and small-for-gestational-age births. However, the exact molecular mechanisms underlying cART-induced adverse pregnancy outcomes remain poorly defined.

OBJECTIVES

To investigate the effects of cART drugs on trophoblast proliferation in the HTR-8/SVneo cell line.

STUDY DESIGN

HTR-8/SVneo cells were exposed to tenofovir (0.983-9.83 µM), emtricitabine (0.809-8.09 µM) and efavirenz (0.19-1.09 µM), the individual drugs of the first-line single tablet cART regimen termed 'Atripla', and zidovudine (1.12-1.12 µM), lamivudine (0.65-6.5 µM), lopinavir (0.32-3.2 µM) and ritonavir (0.69-6.9 µM), the individual drugs of the second-line single tablet cART regimen termed 'Aluvia'. The cells were treated for 24, 48, 72 and 96 h, and trophoblast proliferation was assessed using a colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltretrazolium bromide assay.

RESULTS

Two-way analysis of variance showed a significant dose-dependent decrease (p < 0.05) in trophoblast proliferation in response to individual and combined drug components of first- and second-line antiretroviral therapy.

CONCLUSIONS

First- and second-line cART drugs inhibit trophoblast proliferation, and may contribute to placenta-mediated adverse pregnancy outcomes in patients with HIV.

Regulation of placental amino acid transport in health and disease

Abnormal fetal growth, i.e., intrauterine growth restriction (IUGR) or fetal growth restriction (FGR) and fetal overgrowth, is associated with increased perinatal morbidity and mortality and is strongly linked to the development of metabolic and cardiovascular disease in childhood and later in life. Emerging evidence suggests that changes in placental amino acid transport may contribute to abnormal fetal growth. This review is focused on amino acid transport in the human placenta, however, relevant animal models will be discussed to add mechanistic insights. At least 25 distinct amino acid transporters with different characteristics and substrate preferences have been identified in the human placenta. Of these, System A, transporting neutral nonessential amino acids, and System L, mediating the transport of essential amino acids, have been studied in some detail. Importantly, decreased placental Systems A and L transporter activity is strongly associated with IUGR and increased placental activity of these two amino acid transporters has been linked to fetal overgrowth in human pregnancy. An array of factors in the maternal circulation, including insulin, IGF-1, and adiponectin, and placental signaling pathways such as mTOR, have been identified as key regulators of placental Systems A and L. Studies using trophoblast-specific gene targeting in mice have provided compelling evidence that changes in placental Systems A and L are mechanistically linked to altered fetal growth. It is possible that targeting specific placental amino acid transporters or their upstream regulators represents a novel intervention to alleviate the short- and long-term consequences of abnormal fetal growth in the future.

A hidden proteome encoded by circRNAs in human placentas: Implications for uncovering preeclampsia pathogenesis

BACKGROUND

CircRNA-encoded proteins (CEPs) are emerging as new players in health and disease, and function as baits for the common partners of their cognate linear-spliced RNA encoded proteins (LEPs). However, their prevalence across human tissues and biological roles remain largely unexplored. The placenta is an ideal model for identifying CEPs due to its considerable protein diversity that is required to sustain fetal development during pregnancy. The aim of this study was to evaluate circRNA translation in the human placenta, and the potential roles of the CEPs in placental development and dysfunction.

METHODS

Multiomics approaches, including RNA sequencing, ribosome profiling, and LC-MS/MS analysis, were utilised to identify novel translational events of circRNAs in human placentas. Bioinformatics methods and the protein bait hypothesis were employed to evaluate the roles of these newly discovered CEPs in placentation and associated disorders. The pathogenic role of a recently identified CEP circPRKCB119aa in preeclampsia was investigated through qRT-PCR, Western blotting, immunofluorescence imaging and phenotypic analyses.

RESULTS

We found that 528 placental circRNAs bound to ribosomes with active translational elongation, and 139 were translated to proteins. The CEPs showed considerable structural homology with their cognate LEPs, but are more stable, hydrophobic and have a lower molecular-weight than the latter, all of which are conducive to their function as baits. On this basis, CEPs are deduced to be closely involved in placental function. Furthermore, we focused on a novel CEP circPRKCB119aa, and illuminated its pathogenic role in preeclampsia; it enhanced trophoblast autophagy by acting as a bait to inhibit phosphorylation of the cognate linear isoform PKCβ.

CONCLUSIONS

We discovered a hidden circRNA-encoded proteome in the human placenta, which offers new insights into the mechanisms underlying placental development, as well as placental disorders such as preeclampsia. Key points A hidden circRNA-encoded proteome in the human placenta was extensively identified and systematically characterised. The circRNA-encoded proteins (CEPs) are potentially related to placental development and associated disorders. A novel conserved CEP circPRKCB119aa enhanced trophoblast autophagy by inhibiting phosphorylation of its cognate linear-spliced isoform protein kinase C (PKC) β in preeclampsia.

Clinical value of placental examination for paediatricians

The placenta contains valuable clinical information that is linked to fetal development, neonatal morbidity and mortality, and future health outcomes. Both gross inspection and histopathological examination of the placenta may identify intrinsic or secondary placental lesions, which can contribute directly to adverse neonatal outcomes or indicate the presence of an unfavourable intrauterine environment. Placental examination therefore forms an essential component of the care of high-risk neonates and at perinatal post-mortem examination. In this article, we describe the clinical value of placental examination for paediatricians and perinatal clinicians. We discuss common pathological findings on general inspection of the placenta with photographic examples and provide an overview of the placental pathological examination, including how to interpret key findings. We also address the medico-legal and financial implications of placental examinations and describe current and future clinical considerations for clinicians in regard to placental examination.

Uncovering the role of TET2-mediated ENPEP activation in trophoblast cell fate determination

Early trophoblast differentiation is crucial for embryo implantation, placentation and fetal development. Dynamic changes in DNA methylation occur during preimplantation development and are critical for cell fate determination. However, the underlying regulatory mechanism remains unclear. Recently, we derived morula-like expanded potential stem cells from human preimplantation embryos (hEPSC-em), providing a valuable tool for studying early trophoblast differentiation. Data analysis on published datasets showed differential expressions of DNA methylation enzymes during early trophoblast differentiation in human embryos and hEPSC-em derived trophoblastic spheroids. We demonstrated downregulation of DNA methyltransferase 3 members (DNMT3s) and upregulation of ten-eleven translocation methylcytosine dioxygenases (TETs) during trophoblast differentiation. While DNMT inhibitor promoted trophoblast differentiation, TET inhibitor hindered the process and reduced implantation potential of trophoblastic spheroids. Further integrative analysis identified that glutamyl aminopeptidase (ENPEP), a trophectoderm progenitor marker, was hypomethylated and highly expressed in trophoblast lineages. Concordantly, progressive loss of DNA methylation in ENPEP promoter and increased ENPEP expression were detected in trophoblast differentiation. Knockout of ENPEP in hEPSC-em compromised trophoblast differentiation potency, reduced adhesion and invasion of trophoblastic spheroids, and impeded trophoblastic stem cell (TSC) derivation. Importantly, TET2 was involved in the loss of DNA methylation and activation of ENPEP expression during trophoblast differentiation. TET2-null hEPSC-em failed to produce TSC properly. Collectively, our results illustrated the crucial roles of ENPEP and TET2 in trophoblast fate commitments and the unprecedented TET2-mediated loss of DNA methylation in ENPEP promoter.

Sequential emergence and contraction of epithelial subtypes in the prenatal human choroid plexus revealed by a stem cell model

Despite the major roles of choroid plexus epithelial cells (CPECs) in brain homeostasis and repair, their developmental lineage and diversity remain undefined. In simplified differentiations from human pluripotent stem cells, derived CPECs (dCPECs) displayed canonical properties and dynamic multiciliated phenotypes that interacted with Aβ uptake. Single dCPEC transcriptomes over time correlated well with human organoid and fetal CPECs, while pseudotemporal and cell cycle analyses highlighted the direct CPEC origin from neuroepithelial cells. In addition, time series analyses defined metabolic (type 1) and ciliogenic dCPECs (type 2) at early timepoints, followed by type 1 diversification into anabolic-secretory (type 1a) and catabolic-absorptive subtypes (type 1b) as type 2 cells contracted. These temporal patterns were then confirmed in independent derivations and mapped to prenatal stages using human tissues. In addition to defining the prenatal lineage of human CPECs, these findings suggest new dynamic models of ChP support for the developing human brain.

Transcriptomic comparison of in vitro models of the human placenta

Studying the human placenta through in vitro cell culture methods is necessary due to limited access and amenability of human placental tissue to certain experimental methods as well as distinct anatomical and physiological differences between animal and human placentas. Selecting an in vitro culture model of the human placenta is challenging due to representation of different trophoblast cell types with distinct biological roles and limited comparative studies that define key characteristics of these models. Therefore, the aim of this research was to create a comprehensive transcriptomic comparison of common in vitro models of the human placenta compared to bulk placental tissue from the CANDLE and GAPPS cohorts (N=1083). We performed differential gene expression analysis on publicly available RNA sequencing data from 6 common in vitro models of the human placenta (HTR-8/SVneo, BeWo, JEG-3, JAR, Primary Trophoblasts, and Villous Explants) and compared to CANDLE and GAPPS bulk placental tissue or cytotrophoblast, syncytiotrophoblast, and extravillous trophoblast cell types derived from bulk placental tissue. All in vitro placental models had a substantial number of differentially expressed genes (DEGs, FDR<0.01) compared to the CANDLE and GAPPS placentas (Average DEGs=10,873), and the individual trophoblast cell types (Average DEGs=5,346), indicating that there are vast differences in gene expression compared to bulk and cell-type specific human placental tissue. Hierarchical clustering identified 53 gene clusters with distinct expression profiles across placental models, with 22 clusters enriched for specific KEGG pathways, 7 clusters enriched for high-expression placental genes, and 7 clusters enriched for absorption, distribution, metabolism, and excretion genes. In vitro placental models were classified by fetal sex based on expression of Y-chromosome genes that identified HTR-8/SVneo cells as being of female origin, while JEG-3, JAR, and BeWo cells are of male origin. Overall, none of the models were a close approximation of the transcriptome of bulk human placental tissue, highlighting the challenges with model selection. To enable researchers to select appropriate models, we have compiled data on differential gene expression, clustering, and fetal sex into an accessible web application: "Comparative Transcriptomic Placental Model Atlas (CTPMA)" which can be utilized by researchers to make informed decisions about their selection of in vitro placental models.

DNA methylation-mediated 11βHSD2 downregulation drives the increases in angiotensin-converting enzyme and angiotensin II within preeclamptic placentas

Preeclampsia (PE) is a complex human-specific complication frequently associated with placental pathology. The local renin-angiotensin system (RAS) in the human placenta, which plays a crucial role in regulating placental function, has been extensively documented. Glucocorticoids (GCs) are a class of steroid hormones. PE cases often have abnormalities in GCs levels and placental GCs barrier. Despite extensive speculation, there is currently no robust evidence indicating that GCs regulate placental RAS. This study aims to investigate these potential relationships. Plasma and placental samples were collected from both normal and PE pregnancies. The levels of angiotensin-converting enzyme (ACE), angiotensin II (Ang II), cortisol, and 11β-hydroxysteroid dehydrogenases (11βHSD) were analyzed. In PE placentas, cortisol, ACE, and Ang II levels were elevated, while 11βHSD2 expression was reduced. Interestingly, a positive correlation was observed between ACE and cortisol levels in the placenta. A significant inverse correlation was found between the methylation statuses within the 11βHSD2 gene promoter and its expression, meanwhile, 11βHSD2 expression was negatively correlated with cortisol and ACE levels. In vitro experiments using placental trophoblast cells confirmed that active GCs can stimulate ACE transcription and expression through the GR pathway. Furthermore, 11βHSD2 knockdown could enhance this activating effect. An in vivo study using a rat model of intrauterine GCs overexposure during mid-to-late gestation suggested that excess GCs in utero lead to increased ACE and Ang II levels in the placenta. Collectively, this study provides the first evidence of the relationships between 11βHSD2 expression, GCs barrier, ACE, and Ang II levels in the placenta. It not only contributes to understanding the pathological features of the placental GCs barrier and RAS under PE conditions, also provides important information for revealing the pathological mechanism of PE.

Sub-Optimal Paternal Diet at the Time of Mating Disrupts Maternal Adaptations to Pregnancy in the Late Gestation Mouse

Pregnancy represents a stage during which maternal physiology and homeostatic regulation undergo dramatic change and adaptation. The fundamental purpose of these adaptations is to ensure the survival of her offspring through adequate nutrient provision and an environment that is tolerant to the semi-allogenic foetus. While poor maternal diet during pregnancy is associated with perturbed maternal adaptations during pregnancy, the influence of paternal diet on maternal well-being is less clearly defined. We fed C57BL/6 male mice either a control (CD), low protein diet (LPD), a high fat/sugar Western diet (WD) or the LPD or WD supplemented with methyl donors (MD-LPD and MD-WD, respectively) for a minimum of 8 weeks prior to mating with C57BL/6 females. Mated females were culled at day 17 of gestation for the analysis of maternal metabolic, gut, cardiac and bone health. Paternal diet had minimal influences on maternal serum and hepatic metabolite levels or gut microbiota diversity. However, analysis of the maternal hepatic transcriptome revealed distinct profiles of differential gene expression in response to the diet of the father. Paternal LPD and MD-LPD resulted in differential expression of genes associated with lipid metabolism, transcription, ubiquitin conjugation and immunity in dams, while paternal WD and MD-WD modified the expression of genes associated with ubiquitin conjugation and cardiac morphology. Finally, we observed changes in maternal femur length, volume of trabecular bone, trabecular connectivity, volume of the cortical medullar cavity and thickness of the cortical bone in response to the father's diets. Our current study demonstrates that poor paternal diet at the time of mating can influence the patterns of maternal metabolism and gestation-associated adaptations to her physiology.

Magnetic resonance imaging of placental intralobule structure and function in a preclinical nonhuman primate model†

Although the central role of adequate blood flow and oxygen delivery is known, the lack of optimized imaging modalities to study placental structure has impeded our understanding of its vascular function. Magnetic resonance imaging is increasingly being applied in this field, but gaps in knowledge remain, and further methodological developments are needed. In particular, the ability to distinguish maternal from fetal placental perfusion and the understanding of how individual placental lobules are functioning are lacking. The potential clinical benefits of developing noninvasive tools for the in vivo assessment of blood flow and oxygenation, two key determinants of placental function, are tremendous. Here, we summarize a number of structural and functional magnetic resonance imaging techniques that have been developed and applied in animal models and studies of human pregnancy over the past decade. We discuss the potential applications and limitations of these approaches. Their combination provides a novel source of contrast to allow analysis of placental structure and function at the level of the lobule. We outline the physiological mechanisms of placental T2 and T2* decay and devise a model of how tissue composition affects the observed relaxation properties. We apply this modeling to longitudinal magnetic resonance imaging data obtained from a preclinical pregnant nonhuman primate model to provide initial proof-of-concept data for this methodology, which quantifies oxygen transfer and placental structure across and between lobules. This method has the potential to improve our understanding and clinical management of placental insufficiency once validation in a larger nonhuman primate cohort is complete.

Mid-pregnancy placental transcriptome in a model of placental insufficiency with and without novel intervention

Fetal growth restriction (FGR) affects between 5-10% of all live births. Placental insufficiency is a leading cause of FGR, resulting in reduced nutrient and oxygen delivery to the fetus. Currently, there are no effective in utero treatment options for FGR, or placental insufficiency. We have developed a gene therapy to deliver, via a non-viral nanoparticle, human insulin-like 1 growth factor ( hIGF1 ) to the placenta as potential treatment of placenta insufficiency and FGR. Using a guinea pig maternal nutrient restriction (MNR) model of FGR, we aimed to understand the transcriptional changes within the placenta associated with placental insufficiency that occur prior to/at initiation of FGR, and the impact of short-term hIGF1 nanoparticle treatment. Using RNAsequencing, we analyzed protein coding genes of three experimental groups: Control and MNR dams receiving a sham treatment, and MNR dams receiving hIGF1 nanoparticle treatment. Pathway enrichment analysis comparing differentially expressed genelists in sham-treated MNR placentas to Control revealed upregulation of pathways associated with degradation and repair of genetic information and downregulation of pathways associated with transmembrane transport. When compared to sham-treated MNR placentas, MNR + hIGF1 placentas demonstrated changes to genelists associated with transmembrane transporter activity including ion, vitamin and solute carrier transport. Overall, this study identifies the key signaling and metabolic changes occurring in the placenta contributing to placental insufficiency prior to/at initiation of FGR, and increases our understanding of the pathways that our nanoparticle-mediated gene therapy intervention regulates.

Statements and Declarations

Competing Interests: Authors declare no conflicts of interest.

Association of Placental Pathology with Physical and Neuronal Development of Infants: A Narrative Review and Reclassification of the Literature by the Consensus Statement of the Amsterdam Placental Workshop Group

The placenta is the largest fetal organ, which connects the mother to the fetus and supports most aspects of organogenesis through the transport of nutrients and gases. However, further studies are needed to assess placental pathology as a reliable predictor of long-term physical growth or neural development in newborns. The Consensus Statement of the Amsterdam Placental Workshop Group (APWGCS) on the sampling and definition of placental lesions has resulted in diagnostic uniformity in describing the most common pathological lesions of the placenta and contributed to the international standardization of descriptions of placental pathology. In this narrative review, we reclassified descriptions of placental pathology from previously published papers according to the APWGCS criteria and comparatively assessed the relationship with infantile physical and/or neural development. After reclassification and reevaluation, placental pathology of maternal vascular malperfusion, one of the APWGCS criteria, emerged as a promising candidate as a universal predictor of negative infantile neurodevelopmental outcomes, not only in term and preterm deliveries but also in high-risk groups of very low birthweight newborns. However, there are few studies that examined placental pathology according to the full categories of APWGCS and also included low-risk general infants. It is necessary to incorporate the assessment of placental pathology utilizing APWGCS in the design of future birth cohort studies as well as in follow-up investigations of high-risk infants.

First Trimester Placental Biomarkers for Pregnancy Outcomes

The placenta plays a key role in several adverse obstetrical outcomes, such as preeclampsia, intrauterine growth restriction and gestational diabetes mellitus. The early identification of at-risk pregnancies could significantly improve the management, therapy and prognosis of these pregnancies, especially if these at-risk pregnancies are identified in the first trimester. The aim of this review was to summarize the possible biomarkers that can be used to diagnose early placental dysfunction and, consequently, at-risk pregnancies. We divided the biomarkers into proteins and non-proteins. Among the protein biomarkers, some are already used in clinical practice, such as the sFLT1/PLGF ratio or PAPP-A; others are not yet validated, such as HTRA1, Gal-3 and CD93. In the literature, many studies analyzed the role of several protein biomarkers, but their results are contrasting. On the other hand, some non-protein biomarkers, such as miR-125b, miR-518b and miR-628-3p, seem to be linked to an increased risk of complicated pregnancy. Thus, a first trimester heterogeneous biomarkers panel containing protein and non-protein biomarkers may be more appropriate to identify and discriminate several complications that can affect pregnancies.

Maternal obesity and placental function: impaired maternal-fetal axis

The prevalence of maternal obesity rapidly increases, which represents a major public health concern worldwide. Maternal obesity is characteristic by metabolic dysfunction and chronic inflammation. It is associated with health problems in both mother and offspring. Increasing evidence indicates that the placenta is an axis connecting maternal obesity with poor outcomes in the offspring. In this brief review, we have summarized the current data regarding deregulated placental function in maternal obesity. The data show that maternal obesity induces numerous placental defects, including lipid and glucose metabolism, stress response, inflammation, immune regulation and epigenetics. These placental defects affect each other and result in a stressful intrauterine environment, which transduces and mediates the adverse effects of maternal obesity to the fetus. Further investigations are required to explore the exact molecular alterations in the placenta in maternal obesity, which may pave the way to develop specific interventions for preventing epigenetic and metabolic programming in the fetus.

Influenza A virus infection disrupts the function of syncytiotrophoblast cells and contributes to adverse pregnancy outcomes

Pregnancy heightens susceptibility to influenza A virus (IAV) infection, thereby increasing the risk of severe pneumonia and maternal mortality. It also raises the chances of adverse outcomes in offspring, such as fetal growth restriction, preterm birth, miscarriage, and stillbirth in offsprings. However, the underlying mechanisms behind these effects remain largely unknown. Syncytiotrophoblast cells, crucial in forming the placental barrier, nutrient exchange and hormone secretion, have not been extensively studied for their responses to IAV. In our experiment, we used Forskolin-treated BeWo cells to mimic syncytiotrophoblast cells in vitro, and infected them with H1N1, H5N1 and H7N9 virus stains. Our results showed that syncytiotrophoblast cells, with their higher intensity of sialic acid receptors, strongly support IAV infection and replication. Notably, high-dose viral infection and prolonged exposure resulted in a significant decrease in fusion index, as well as gene and protein expression levels associated with trophoblast differentiation, β-human chorionic gonadotropin secretion, estrogen and progesterone biosynthesis, and nutrient transport. In pregnant BALB/c mice infected with the H1N1 virus, we observed significant decreases in trophoblast differentiation and hormone secretion gene expression levels. IAV infection also resulted in preterm labor, fetal growth restriction, and increased maternal and fetal morbidity and mortality. Our findings indicate that IAV infection in syncytiotrophoblastic cells can result in adverse pregnancy outcomes by altering trophoblast differentiation, suppressing of β-hCG secretion, and disrupting placental barrier function.

Pre-eclampsia: Re-visiting pathophysiology, role of immune cells, biomarker identification and recent advances in its management

Pre-eclampsia (PE) is a hypertension condition that occurs exclusively during pregnancy and has the potential to impact nearly all organ systems. It is estimated to complicate approximately 2-8% of pregnancies worldwide. PE is a prominent medical disorder that poses a significant risk to pregnant mothers and their infants. This review commences by giving the most up-to- date concepts about the pathophysiology of PE. The condition involves atypical infiltration of trophoblast cells into the spiral arteries of the decidua and myometrium, resulting in an insufficient establishment of proper blood flow between the uterus and placenta. The aberrant activation of natural killer (NK) cells in both the peripheral blood and the decidua has been identified as one of the contributing factors to the development of PE. The strong evidence for the genetic etiology of PE is provided by the association between maternal killer cell immunoglobulin-like receptor (KIR) and Human Leukocyte Antigen (HLA-C) in trophoblast cells. Recent observations provide evidence that changes in the expression of anti-angiogenic factors in the placenta are the underlying cause of the clinical symptoms associated with the condition. This review also provides a comprehensive overview of the latest advancements in understanding the underlying causes of PE. It specifically highlights the emergence of new diagnostic biomarkers and their potential implications for therapeutic interventions in managing this medical condition.

Associations of per- and polyfluoroalkyl substances with maternal metabolic and inflammatory biomarkers in early-to-mid-pregnancy

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) can disrupt metabolism. Early-to-mid pregnancy is characterized by amplified metabolic processes and inflammation to support maternal adaptations and fetal growth. Thus, we cross-sectionally evaluated whether PFAS are individually and jointly associated with these processes in early-to-mid pregnancy.

METHODS

Pregnant Illinois women (n = 452) provided fasted blood samples at median 17 weeks gestation. We quantified serum perfluorononanoic (PFNA), perfluorooctane sulfonic (PFOS), perfluorooctanoic (PFOA), methyl-perfluorooctane sulfonamide acetic acid (Me-PFOSA-AcOH), perfluorohexanesulfonic (PFHxS), perfluorodecanoic (PFDeA), and perfluoroundecanoic (PFUdA) acid. Key outcomes were plasma glucose, insulin, C-peptide, insulin-like growth factor 1 (IGF-1), adiponectin, leptin, triglycerides, free fatty acids, total cholesterol, high-density lipoprotein (HDL) cholesterol, C-reactive protein, tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and interleukin 6. We calculated homeostatic model assessment for insulin resistance (HOMA-IR), low-density lipoprotein (LDL) cholesterol, and very low-density lipoprotein (VLDL). We evaluated associations of PFAS with each metabolic/inflammatory biomarker individually using covariate-adjusted linear regression and jointly using quantile-based g-computation.

RESULTS

In linear regression, all PFAS (except Me-PFOSA-AcOH) were negatively associated with insulin, HOMA-IR, and leptin, whereas all PFAS were positively associated with HDL cholesterol. We also observed negative associations of some PFAS with TNF-α and MCP-1; positive associations with adiponectin and total cholesterol also emerged. Additionally, PFOS was positively, whereas Me-PFOSA-AcOH was negatively, associated with triglycerides and VLDL. Each 25% increase in the PFAS mixture was associated with -31.3% lower insulin (95%CI: -45.8, -12.9), -31.9% lower HOMA-IR (95%CI: -46.4, -13.4), and -9.4% lower leptin (95%CI: -17.3, -0.8), but 7.4% higher HDL cholesterol (95%CI: 4.6, 10.3). For most outcomes, the major contributors to the PFAS mixture often differed compared to single-PFAS analyses.

IMPLICATIONS

Individual and joint PFAS exposures were associated with markers of maternal metabolism and inflammation in pregnancy. Further investigation is needed to elucidate possible mechanisms and consequences of these findings.

Advanced magnetic resonance imaging detects altered placental development in pregnancies affected by congenital heart disease

Congenital heart disease (CHD) is the most common congenital malformation and is associated with adverse neurodevelopmental outcomes. The placenta is crucial for healthy fetal development and placental development is altered in pregnancy when the fetus has CHD. This study utilized advanced combined diffusion-relaxation MRI and a data-driven analysis technique to test the hypothesis that placental microstructure and perfusion are altered in CHD-affected pregnancies. 48 participants (36 controls, 12 CHD) underwent 67 MRI scans (50 control, 17 CHD). Significant differences in the weighting of two independent placental and uterine-wall tissue components were identified between the CHD and control groups (both pFDR < 0.001), with changes most evident after 30 weeks gestation. A significant trend over gestation in weighting for a third independent tissue component was also observed in the CHD cohort (R = 0.50, pFDR = 0.04), but not in controls. These findings add to existing evidence that placental development is altered in CHD. The results may reflect alterations in placental perfusion or the changes in fetal-placental flow, villous structure and maturation that occur in CHD. Further research is needed to validate and better understand these findings and to understand the relationship between placental development, CHD, and its neurodevelopmental implications.

Titanium Dioxide Nanoparticles Induce Maternal Preeclampsia-like Syndrome and Adverse Birth Outcomes via Disrupting Placental Function in SD Rats

The escalating utilization of titanium dioxide nanoparticles (TiO2 NPs) in everyday products has sparked concerns regarding their potential hazards to pregnant females and their offspring. To address these concerns and shed light on their undetermined adverse effects and mechanisms, we established a pregnant rat model to investigate the impacts of TiO2 NPs on both maternal and offspring health and to explore the underlying mechanisms of those impacts. Pregnant rats were orally administered TiO2 NPs at a dose of 5 mg/kg body weight per day from GD5 to GD18 during pregnancy. Maternal body weight, organ weight, and birth outcomes were monitored and recorded. Maternal pathological changes were examined by HE staining and TEM observation. Maternal blood pressure was assessed using a non-invasive blood analyzer, and the urinary protein level was determined using spot urine samples. Our findings revealed that TiO2 NPs triggered various pathological alterations in maternal liver, kidney, and spleen, and induced maternal preeclampsia-like syndrome, as well as leading to growth restriction in the offspring. Further examination unveiled that TiO2 NPs hindered trophoblastic cell invasion into the endometrium via the promotion of autophagy. Consistent hypertension and proteinuria resulted from the destroyed the kidney GBM. In total, an exposure to TiO2 NPs during pregnancy might increase the risk of human preeclampsia through increased maternal arterial pressure and urinary albumin levels, as well as causing fetal growth restriction in the offspring.

Placental Drug Delivery to Treat Pre-Eclampsia and Fetal Growth Restriction

Pre-eclampsia and fetal growth restriction (FGR) continue to cause unacceptably high levels of morbidity and mortality, despite significant pharmaceutical and technological advances in other disease areas. The recent pandemic has also impacted obstetric care, as COVID-19 infection increases the risk of poor pregnancy outcomes. This review explores the reasons why it lacks effective drug treatments for the placental dysfunction that underlies many common obstetric conditions and describes how nanomedicines and targeted drug delivery approaches may provide the solution to the current drug drought. The ever-increasing range of biocompatible nanoparticle formulations available is now making it possible to selectively deliver drugs to uterine and placental tissues and dramatically limit fetal drug transfer. Formulations that are refractory to placental uptake offer the possibility of retaining drugs within the maternal circulation, allowing pregnant individuals to take medicines previously considered too harmful to the developing baby. Liposomes, ionizable lipid nanoparticles, polymeric nanoparticles, and adenoviral vectors have all been used to create efficacious drug delivery systems for use in pregnancy, although each approach offers distinct advantages and limitations. It is imperative that recent advances continue to be built upon and that there is an overdue investment of intellectual and financial capital in this field.

The protective effects of Ferrostatin-1 against inflammation-induced preterm birth and fetal brain injury

INTRODUCTION

Recent studies have suggested the involvement of ferroptosis in preterm birth. Despite compelling evidence, the underlying mechanism remains unknown. This investigation aimed to determine the therapeutic effects of Ferrostatin-1 (Fer-1), an inhibitor of ferroptosis, in preterm birth and fetal brain injury.

METHODS

Human placenta samples and clinical data of participants were collected to ascertain whether placental ferroptosis was associated with preterm birth. Lipopolysaccharide (LPS)-induced preterm birth mouse model was used to examine the protective effects of Fer-1 on preterm birth. Fetal brain tissues and offspring mice at 5 and 8 weeks were studied to determine the effects of Fer-1 on the cognitive function of offspring.

RESULTS

We examined the mechanism of spontaneous preterm birth and discovered that placental ferroptosis was associated with preterm birth. Fer-1 inhibited preterm birth by ameliorating placental ferroptosis and maternal inflammation, thus improving LPS-induced intrauterine inflammation to maintain pregnancy. Antenatal administration of Fer-1 prevented LPS-induced fetal brain damage in the acute phase and improved long-term neurodevelopmental impairments by improving placental neuroendocrine signaling and maintaining placental function.

CONCLUSION

Fer-1 inhibited preterm birth and fetal brain injury by inhibiting maternal inflammation and improving placental function. Our findings provide a novel therapeutic strategy for preterm birth.

Impact of maternal immune activation and sex on placental and fetal brain cytokine and gene expression profiles in a preclinical model of neurodevelopmental disorders

Maternal inflammation during gestation is associated with a later diagnosis of neurodevelopmental disorders including autism spectrum disorder (ASD). However, the specific impact of maternal immune activation (MIA) on placental and fetal brain development remains insufficiently understood. This study aimed to investigate the effects of MIA by analyzing placental and brain tissues obtained from the offspring of pregnant C57BL/6 dams exposed to polyinosinic: polycytidylic acid (poly I: C) on embryonic day 12.5. Cytokine and mRNA content in the placenta and brain tissues were assessed using multiplex cytokine assays and bulk-RNA sequencing on embryonic day 17.5. In the placenta, male MIA offspring exhibited higher levels of GM-CSF, IL-6, TNFα, and LT-α, but there were no differences in female MIA offspring. Furthermore, differentially expressed genes (DEG) in the placental tissues of MIA offspring were found to be enriched in processes related to synaptic vesicles and neuronal development. Placental mRNA from male and female MIA offspring were both enriched in synaptic and neuronal development terms, whereas females were also enriched for terms related to excitatory and inhibitory signaling. In the fetal brain of MIA offspring, increased levels of IL-28B and IL-25 were observed with male MIA offspring and increased levels of LT-α were observed in the female offspring. Notably, we identified few stable MIA fetal brain DEG, with no male specific difference whereas females had DEG related to immune cytokine signaling. Overall, these findings support the hypothesis that MIA contributes to the sex- specific abnormalities observed in ASD, possibly through altered neuron developed from exposure to inflammatory cytokines. Future research should aim to investigate how interactions between the placenta and fetal brain contribute to altered neuronal development in the context of MIA.

Childhood atopic disorders in relation to placental changes-A systematic review and meta-analysis

Fetal programming may arise from prenatal exposure and increase the risk of diseases later in life, potentially mediated by the placenta. The objective of this systematic review was to summarize and critically evaluate publications describing associations between human placental changes and risk of atopic disorders during childhood. The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. The inclusion criteria were original research articles or case reports written in English describing a human placental change in relation to disease occurring in offspring during childhood. The MEDLINE and EMBASE databases were searched for eligible studies. Risk of bias (RoB) was assessed using the ROBINS-I tool. The results were pooled both in a narrative way and by a meta-analysis. Nineteen studies were included (n = 12,997 participants). All studies had an overall serious RoB, and publication bias could not be completely ruled out. However, five studies showed that histological chorioamnionitis in preterm-born children was associated with asthma-related problems (pooled odds ratio = 3.25 (95% confidence interval = 2.22-4.75)). In term-born children, a large placenta (≥750 g) increased the risk of being prescribed anti-asthma medications during the first year of life. Placental histone acetylation, DNA methylation, and gene expression differences were found to be associated with different atopic disorders in term-born children. There is some evidence supporting the idea that the placenta can mediate an increased risk of atopic disorders in children. However, further studies are needed to validate the findings, properly control for confounders, and examine potential mechanisms.

The effects of inhaled pollutants on reproduction in marginalized communities: a contemporary review

Important differences in health that are closely linked with social disadvantage exist within and between countries. According to the World Health Organization, life expectancy and good health continue to increase in many parts of the world, but fail to improve in other parts of the world, indicating that differences in life expectancy and health arise due to the circumstances in which people grow, live, work, and age, and the systems put in place to deal with illness. Marginalized communities experience higher rates of certain diseases and more deaths compared to the general population, indicating a profound disparity in health status. Although several factors place marginalized communities at high risk for poor health outcomes, one important factor is exposure to air pollutants. Marginalized communities and minorities are exposed to higher levels of air pollutants than the majority population. Interestingly, a link exists between air pollutant exposure and adverse reproductive outcomes, suggesting that marginalized communities may have increased reproductive disorders due to increased exposure to air pollutants compared to the general population. This review summarizes different studies showing that marginalized communities have higher exposure to air pollutants, the types of air pollutants present in our environment, and the associations between air pollution and adverse reproductive outcomes, focusing on marginalized communities.

Maternal periodontal diseases affect the leukocyte profiles of umbilical cord blood: A cohort study

AIM

This study evaluated the connection of periodontal status with the leukocyte profiles of maternal peripheral blood (MPB) and umbilical cord blood (UCB).

MATERIALS AND METHODS

Ninety-nine pregnant females were recruited, and their data were collected via questionnaire and from medical records, including demographics, systemic conditions, complete blood count (CBC) and C-reaction protein (CRP) level in MPB. Full-mouth periodontal assessment was performed. CBC and CRP levels in UCB were measured after parturition.

RESULTS

All subjects and their neonates were generally healthy. 30.3% of the participants presented with periodontal health condition, whereas 69.7% had different severities of periodontal diseases. The counts/percentages of eosinophils and monocytes in UCB from the subjects with periodontal diseases elevated, and the percentage of neutrophils decreased referencing to that from the counterparts (p < 0.05). There were positive correlations for total leukocyte count, neutrophils and lymphocytes counts/percentages in MPB and UCB among the periodontally healthy subjects (r > 0.4, p < 0.05), but such findings did not exist in those with periodontal diseases. Moreover, periodontal diseases independently accounted for the counts/percentages of neutrophils and eosinophils in UCB after controlling confounders in four testing models (ANCOVA, p < 0.05).

CONCLUSION

Maternal periodontal diseases could to some extent disturb the leukocyte profiles of umbilical cord blood.

NANOG regulate the JAK/STAT3 pathway to promote trophoblast cell migration and epithelial-mesenchymal transition (EMT) in hypertensive disorders of pregnancy (HDP) through protein interaction with CDK1

PROBLEM

Hypertensive disorders of pregnancy (HDP) are a common pregnancy disease. NANOG and Cyclin-dependent kinase 1 (CDK1) are essential for regulating the function of cell proliferation and apoptosis. However, the mechanism of action in HDP is yet unclear.

METHOD

The microarray dataset GSE6573 was downloaded from the GEO database. Emt-related gene set was downloaded from Epithelial-Mesenchymal Transition gene database 2.0 were screened differentially expressed genes by bioinformatics analysis. Pathway Commons and Scansite 4.0 databases were used to predict the interaction between proteins. Placental tissue samples were collected from HDP patients and patients with uneventful pregnancies. RT-qPCR, Western blot and immunohistochemistry were used to detect the expression of NANOG, CDK1, MMP-2, MMP-9, EMT markers and the JAK/STAT3 pathway proteins. Transfection NANOG overexpression/knockdown, and CDK1 knockdown into the human chorionic trophoblast cells (HTR-8/Svneo). CCK-8, Transwell and Wound-healing assay were used to evaluate cell proliferation, invasion and migration. CO-IP and GST pull-down assays were used to confirm the protein interaction.

RESULTS

A total obtained seven EMT-related differentially expressed genes, wherein NANOG, NODAL and LIN28A had protein interaction. In the HDP patients' tissue found that NANOG and CDK1 had lower expression. NANOG overexpression promoted HTR-8/Svneo proliferation, migration and EMT, while NANOG knockdown had the opposite effect. Further a protein interaction between STAT3 and CDK1 with NANOG. NANOG overexpression downregulated the JAK/STAT3 pathway to promote HTR-8/Svneo proliferation, migration and EMT, which was reversed by CDK1 knockdown.

CONCLUSIONS

NANOG downregulated the JAK/STAT3 pathway to promote trophoblast cell proliferation, migration and EMT through protein interaction with CDK1.

Targeting Mitochondrial Oxidative Stress to Protect Against Preterm Birth and Fetal Brain Injury via Nrf2 Induction

Aims: Preterm birth (PTB), recognized as delivery before 37 weeks of gestation, is a multifactorial syndrome characterizing as the main cause of neonatal mortality. Reactive oxygen species (ROS) have been identified as proinflammatory factors to cause placental inflammation, thereby resulting in several pregnancy outcomes. To date, limited knowledge regarding the underlying mechanisms of ROS-induced PTB has been reported. In this study, we aimed to investigate the role of oxidative stress in PTB and the protective effects of mitochondria-targeted antioxidant MitoTEMPO (MT) on preterm labor and offspring mice. Results: In this study, we found that preterm placentas had abnormal mitochondrial function, oxidative stress, and inflammatory response. In the lipopolysaccharide (LPS)-induced PTB mouse model, MT inhibited PTB by ameliorating maternal oxidative stress and inflammation, especially in placentas, thus improving placental function to maintain pregnancy. Antenatal administration of MT prevented LPS-induced fetal brain damage in acute phase and improved long-term neurodevelopmental impairments. Furthermore, our in vitro investigations validated that MT retarded the ROS accumulation and inflammatory response in LPS-stimulated trophoblast cells by promoting Kelch-like ECH-associated protein 1 (Keap1) degradation and subsequently activating nuclear factor erythroid 2-related factor 2 (Nrf2). By inhibiting Nrf2 activation, we discovered that the anti-inflammation and protective characteristics of MT were Nrf2/ARE pathway dependent. Innovation and Conclusion: MT inhibited PTB and fetal brain injury by inhibiting maternal inflammation and improving placental function through Keap1/Nrf2/antioxidant response element signaling pathway. Our findings provide a novel therapeutic strategy for PTB.

Gestational exposure to PM2.5 disrupts fetal development by suppressing placental trophoblast syncytialization via progranulin/mTOR signaling

Recent epidemiological and animal studies have indicated that ambient fine particulate matter (PM2.5) exposure during pregnancy is closely associated with intrauterine growth restriction (IUGR). However, the underlying mechanisms remain to be revealed. In this study, we found that gestational exposure to PM2.5 significantly decreased fetal weight and crown-rump length in mice, accompanied by insufficient placental trophoblast syncytialization and increased expression of progranulin (PGRN) in mice placenta. Administering PGRN neutralizing antibody to pregnant mice alleviated growth restriction and insufficient placental trophoblast syncytialization caused by PM2.5, accompanied with suppressed activation of the mTOR signaling pathway. Furthermore, in vitro experiments using human placental BeWo cells showed that 10 μg·mL-1 PM2.5 activated PGRN/mTOR signaling and suppressed forskolin-induced cell fusion, which was blocked by knockdown of PGRN. Taken together, our results demonstrated that PM2.5 exposure during pregnancy inhibited placental trophoblast syncytialization by activating PGRN/mTOR signaling, leading to abnormal placental development and IUGR. This study reveals a novel mechanism underlying the developmental toxicity of PM2.5 exposure during pregnancy.

Placental Nanoparticle-mediated IGF1 Gene Therapy Corrects Fetal Growth Restriction in a Guinea Pig Model

Fetal growth restriction (FGR) caused by placental insufficiency is a major contributor to neonatal morbidity and mortality. There is currently no in utero treatment for placental insufficiency or FGR. The placenta serves as the vital communication, supply, exchange, and defense organ for the developing fetus and offers an excellent opportunity for therapeutic interventions. Here we show efficacy of repeated treatments of trophoblast-specific human insulin-like 1 growth factor ( IGF1 ) gene therapy delivered in a non-viral, polymer nanoparticle to the placenta for the treatment of FGR. Using the guinea pig maternal nutrient restriction model of FGR, nanoparticle-mediated IGF1 treatment was delivered to the placenta via ultrasound guidance across the second half of pregnancy, after establishment of FGR. This treatment resulted in correction of fetal weight in MNR animals compared to control, improved fetal physiology and no negative maternal side-effects. Overall, we show for the first time a therapy capable of improving the entire pregnancy environment: maternal, placental, and fetal. This combined with our previous studies using this therapy at both mid pregnancy and in numerous cell and animal models demonstrate the plausibility of this therapy for future human translation to improve health outcomes of neonates and decrease numerous morbidities associated with the developmental origins of disease.

Proteomic studies of VEGFR2 in human placentas reveal protein associations with preeclampsia, diabetes, gravidity, and labor

VEGFR2 (Vascular endothelial growth factor receptor 2) is a central regulator of placental angiogenesis. The study of the VEGFR2 proteome of chorionic villi at term revealed its partners MDMX (Double minute 4 protein) and PICALM (Phosphatidylinositol-binding clathrin assembly protein). Subsequently, the oxytocin receptor (OT-R) and vasopressin V1aR receptor were detected in MDMX and PICALM immunoprecipitations. Immunogold electron microscopy showed VEGFR2 on endothelial cell (EC) nuclei, mitochondria, and Hofbauer cells (HC), tissue-resident macrophages of the placenta. MDMX, PICALM, and V1aR were located on EC plasma membranes, nuclei, and HC nuclei. Unexpectedly, PICALM and OT-R were detected on EC projections into the fetal lumen and OT-R on 20-150 nm clusters therein, prompting the hypothesis that placental exosomes transport OT-R to the fetus and across the blood-brain barrier. Insights on gestational complications were gained by univariable and multivariable regression analyses associating preeclampsia with lower MDMX protein levels in membrane extracts of chorionic villi, and lower MDMX, PICALM, OT-R, and V1aR with spontaneous vaginal deliveries compared to cesarean deliveries before the onset of labor. We found select associations between higher MDMX, PICALM, OT-R protein levels and either gravidity, diabetes, BMI, maternal age, or neonatal weight, and correlations only between PICALM-OT-R (p < 2.7 × 10-8), PICALM-V1aR (p < 0.006), and OT-R-V1aR (p < 0.001). These results offer for exploration new partnerships in metabolic networks, tissue-resident immunity, and labor, notably for HC that predominantly express MDMX.

The Placental Role in Gestational Diabetes Mellitus: A Molecular Perspective

During pregnancy, women undergo several metabolic changes to guarantee an adequate supply of glucose to the foetus. These metabolic modifications develop what is known as physiological insulin resistance. When this process is altered, however, gestational diabetes mellitus (GDM) occurs. GDM is a multifactorial disease, and genetic and environmental factors play a crucial role in its aetiopathogenesis. GDM has been linked to both macroscopic and molecular alterations in placental tissues that affect placental physiology. This review summarizes the role of the placenta in the development of GDM from a molecular perspective, including hormonal and pro-inflammatory changes. Inflammation and hormonal imbalance, the characteristics dominating the GDM microenvironment, are responsible for placental changes in size and vascularity, leading to dysregulation in maternal and foetal circulations and to complications in the newborn. In conclusion, since the hormonal mechanisms operating in GDM have not been fully elucidated, more research should be done to improve the quality of life of patients with GDM and their future children.

Fluoride-related changes in the fetal cord blood proteome; a pilot study

Background

Fluoride exposure during pregnancy has been associated with various effects on offspring, including changes in behavior and IQ. To provide clues to possible mechanisms by which fluoride affects human fetal development, we completed proteomic analyses of cord blood serum collected from second-trimester pregnant women residing in Northern California with either high or low fluoride exposure, as identified by maternal serum fluoride concentrations.

Objective

To identify changes in cord blood proteins associated with maternal serum fluoride concentration in pregnant women living in Northern California.

Methods

The proteomes of 19 archived second-trimester cord blood samples representing highest and lowest serum fluoride concentrations from a cohort of 48 women living in Northern California, previously analyzed for serum, urine and amniotic fluoride concentrations, were characterized by mass spectrometry. Proteins highly correlated to maternal serum fluoride concentrations were identified, and further compared in a group of samples from women with the highest serum fluoride to the group with the lowest maternal serum fluoride concentrations.

Results

Nine cord blood proteins were significantly correlated with maternal serum fluoride concentrations. Six of these proteins, including apolipoprotein B-100, delta homolog 1, coagulation factor X, mimecan, plasma kallikrein, and vasorin, were significantly decreased in the cord blood from women with the highest serum fluoride levels.

Conclusion

Changes in the relative amounts of second trimester cord blood proteins included proteins associated with the development of the fetal hematopoetic system.

Relationship between Androgens and Vascular and Placental Function during Pre-eclampsia

Hypertensive disorders of pregnancy (HDP) represent a substantial risk to maternal and fetal health. Emerging evidence suggests an association between testosterone and pre-eclampsia (PE), potentially mediated through androgen receptors (AR). Nevertheless, the mechanism driving this association is yet to be elucidated. On the other hand, reports of transgender men's pregnancies offer a limited and insightful opportunity to understand the role of high androgen levels in the development of HDP. In this sense, a literature review was performed from a little over 2 decades (1998-2022) to address the association of testosterone levels with the development of HDP. Furthermore, this review addresses the case of transgender men for the first time. The main in vitro outcomes reveal placenta samples with greater AR mRNA expression. Moreover, ex vivo studies show that testosterone-induced vasorelaxation impairment promotes hypertension. Epidemiological data point to greater testosterone levels in blood samples during PE. Studies with transgender men allow us to infer that exogenous testosterone administration can be considered a risk factor for PE and that the administration of testosterone does not affect fetal development. Overall, all studies analyzed suggested that high testosterone levels are associated with PE.

Sex-dependent placental methylation quantitative trait loci provide insight into the prenatal origins of childhood onset traits and conditions

Molecular quantitative trait loci (QTLs) allow us to understand the biology captured in genome-wide association studies (GWASs). The placenta regulates fetal development and shows sex differences in DNA methylation. We therefore hypothesized that placental methylation QTL (mQTL) explain variation in genetic risk for childhood onset traits, and that effects differ by sex. We analyzed 411 term placentas from two studies and found 49,252 methylation (CpG) sites with mQTL and 2,489 CpG sites with sex-dependent mQTL. All mQTL were enriched in regions that typically affect gene expression in prenatal tissues. All mQTL were also enriched in GWAS results for growth- and immune-related traits, but male- and female-specific mQTL were more enriched than cross-sex mQTL. mQTL colocalized with trait loci at 777 CpG sites, with 216 (28%) specific to males or females. Overall, mQTL specific to male and female placenta capture otherwise overlooked variation in childhood traits.

Screening the optimal housekeeping genes (HKGs) of placenta tissues by RNA-sequence and qRT-PCR throughout gestation in goat (Capra Hircus)

Selection of stable housekeeping genes (HKGs) is very important for accurate calculation of relative expression levels of target genes by quantitative real-time polymerase chain reaction (qRT-PCR). At present, the appropriate HKGs have not been identified in placental tissues throughout the pregnancy of the goat. In our study, 20 HKGs were tentatively selected from RNA-seq data and previous reports. The cycle threshold (Ct) of HKGs was determined by qRT-PCR in trophoblast membrane and cotyledon villus collected from 38 Dazu Black goats on gestation days of 20, 25, 30, 45, 60, 90, 120, and 150 (birth). The expression stability of the HKGs was analyzed by geNorm, Normfinder, Bestkeeper and Delta Ct algorithms, and comprehensively evaluated by ReFinder and ComprFinder. In addition, the optimal HKGs were further verified by placenta-specific genes (SPP1, VEGFA and PAG6). The 16 candidate HKGs (except POP4, TBP, RNF10, UBC) showed a qualified Ct value, less than 28. Among them, YWHAZ, EIF3K and PPIB showed the most stable expression in placental tissues during early, mid-late pregnancy and postpartum, but the least stable expression was B2M at early and mid-late stage, and PPIB at postpartum. After comprehensive analysis, RPLP0, EIF3K and YWHAZ were found to be the most stable placental HKGs throughout pregnancy. The classical HKGs, ACTB, GAPDH and 18S RNA have unstable expressions and even ranked at the bottom of the list from comprehensive index, suggesting an inappropriate for target gene normalization. Taken together, our study confirmed that YWHAZ, EIF3K, HMBS and RPLP0 may be the optimal HKGs in goat placenta at different stage of pregnancy, which provided a valuable reference of HKGs on functional gene expression detection for further research on placenta development and growth in ruminants.

The differential regulation of placenta trophoblast bisphosphoglycerate mutase in fetal growth restriction: preclinical study in mice and observational histological study of human placenta

Background

Fetal growth restriction (FGR) is a pregnancy complication in which a newborn fails to achieve its growth potential, increasing the risk of perinatal morbidity and mortality. Chronic maternal gestational hypoxia, as well as placental insufficiency are associated with increased FGR incidence; however, the molecular mechanisms underlying FGR remain unknown.

Methods

Pregnant mice were subjected to acute or chronic hypoxia (12.5% O2) resulting in reduced fetal weight. Placenta oxygen transport was assessed by blood oxygenation level dependent (BOLD) contrast magnetic resonance imaging (MRI). The placentae were analyzed via immunohistochemistry and in situ hybridization. Human placentae were selected from FGR and matched controls and analyzed by immunohistochemistry (IHC). Maternal and cord sera were analyzed by mass spectrometry.

Results

We show that murine acute and chronic gestational hypoxia recapitulates FGR phenotype and affects placental structure and morphology. Gestational hypoxia decreased labyrinth area, increased the incidence of red blood cells (RBCs) in the labyrinth while expanding the placental spiral arteries (SpA) diameter. Hypoxic placentae exhibited higher hemoglobin-oxygen affinity compared to the control. Placental abundance of Bisphosphoglycerate mutase (BPGM) was upregulated in the syncytiotrophoblast and spiral artery trophoblast cells (SpA TGCs) in the murine gestational hypoxia groups compared to the control. Hif1α levels were higher in the acute hypoxia group compared to the control. In contrast, human FGR placentae exhibited reduced BPGM levels in the syncytiotrophoblast layer compared to placentae from healthy uncomplicated pregnancies. Levels of 2,3 BPG, the product of BPGM, were lower in cord serum of human FGR placentae compared to control. Polar expression of BPGM was found in both human and mouse placentae syncytiotrophoblast, with higher expression facing the maternal circulation. Moreover, in the murine SpA TGCs expression of BPGM was concentrated exclusively in the apical cell side, in direct proximity to the maternal circulation.

Conclusions

This study suggests a possible involvement of placental BPGM in maternal-fetal oxygen transfer, and in the pathophysiology of FGR.

Funding

This work was supported by the Weizmann Krenter Foundation and the Weizmann - Ichilov (Tel Aviv Sourasky Medical Center) Collaborative Grant in Biomedical Research, by the Minerva Foundation, by the ISF KillCorona grant 3777/19.

Genomic Selection Signals in Andean Highlanders Reveal Adaptive Placental Metabolic Phenotypes That Are Disrupted in Preeclampsia

BACKGROUND

The chronic hypoxia of high-altitude residence poses challenges for tissue oxygen supply and metabolism. Exposure to high altitude during pregnancy increases the incidence of hypertensive disorders of pregnancy and fetal growth restriction and alters placental metabolism. High-altitude ancestry protects against altitude-associated fetal growth restriction, indicating hypoxia tolerance that is genetic in nature. Yet, not all babies are protected and placental pathologies associated with fetal growth restriction occur in some Andean highlanders.

METHODS

We examined placental metabolic function in 79 Andeans (18-45 years; 39 preeclamptic and 40 normotensive) living in La Paz, Bolivia (3600-4100 m) delivered by unlabored Cesarean section. Using a selection-nominated approach, we examined links between putatively adaptive genetic variation and phenotypes related to oxygen delivery or placental metabolism.

RESULTS

Mitochondrial oxidative capacity was associated with fetal oxygen delivery in normotensive but not preeclamptic placenta and was also suppressed in term preeclamptic pregnancy. Maternal haplotypes in or within 200 kb of selection-nominated genes were associated with lower placental mitochondrial respiratory capacity (PTPRD [protein tyrosine phosphatase receptor-δ]), lower maternal plasma erythropoietin (CPT2 [carnitine palmitoyl transferase 2], proopiomelanocortin, and DNMT3 [DNA methyltransferase 3]), and lower VEGF (vascular endothelial growth factor) in umbilical venous plasma (TBX5 [T-box transcription factor 5]). A fetal haplotype within 200 kb of CPT2 was associated with increased placental mitochondrial complex II capacity, placental nitrotyrosine, and GLUT4 (glucose transporter type 4) protein expression.

CONCLUSIONS

Our findings reveal novel associations between putatively adaptive gene regions and phenotypes linked to oxygen delivery and placental metabolic function in highland Andeans, suggesting that such effects may be of genetic origin. Our findings also demonstrate maladaptive metabolic mechanisms in the context of preeclampsia, including dysregulation of placental oxygen consumption.

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.

Placenta-Specific Transcripts Containing Androgen Response Elements Are Altered In Silico by Male Growth Outcomes

A birthweight centile (BWC) below the 25th is associated with an elevated risk of adverse perinatal outcomes, particularly among males. This male vulnerability may stem from alterations in placenta-specific androgen signalling, a signalling axis that involves the androgen receptor (AR)-mediated regulation of target genes containing androgen response elements (AREs). In this study, we examined global and ARE-specific transcriptomic signatures in term male placentae (≥37 weeks of gestation) across BWC subcategories (<10th, 10th-30th, >30th) using RNA-seq and gene set enrichment analysis. ARE-containing transcripts in placentae with BWCs below the 10th percentile were upregulated compared to those in the 10th-30th and >30th percentiles, which coincided with the enrichment of gene sets related to hypoxia and the suppression of gene sets associated with mitochondrial function. In the absence of ARE-containing transcripts in silico, <10th and 10th-30th BWC subcategory placentae upregulated gene sets involved in vasculature development, immune function, and cell adhesion when compared to those in the >30th BWC subcategory. Collectively, our in silico findings suggest that changes in the expression of ARE-containing transcripts in male placentae may contribute to impaired placental vasculature and therefore result in reduced fetal growth outcomes.

Oncostatin M and STAT3 Signaling Pathways Support Human Trophoblast Differentiation by Inhibiting Inflammatory Stress in Response to IFNγ and GM-CSF

Interleukin-6 (IL-6) superfamily cytokines play critical roles during human pregnancy by promoting trophoblast differentiation, invasion, and endocrine function, and maintaining embryo immunotolerance and protection. In contrast, the unbalanced activity of pro-inflammatory factors such as interferon gamma (IFNγ) and granulocyte-macrophage colony-stimulating factor (GM-CSF) at the maternal-fetal interface have detrimental effects on trophoblast function and differentiation. This study demonstrates how the IL-6 cytokine family member oncostatin M (OSM) and STAT3 activation regulate trophoblast fusion and endocrine function in response to pro-inflammatory stress induced by IFNγ and GM-CSF. Using human cytotrophoblast-like BeWo (CT/BW) cells, differentiated in villous syncytiotrophoblast (VST/BW) cells, we show that beta-human chorionic gonadotrophin (βhCG) production and cell fusion process are affected in response to IFNγ or GM-CSF. However, those effects are abrogated with OSM by modulating the activation of IFNγ-STAT1 and GM-CSF-STAT5 signaling pathways. OSM stimulation enhances the expression of STAT3, the phosphorylation of STAT3 and SMAD2, and the induction of negative regulators of inflammation (e.g., IL-10 and TGFβ1) and cytokine signaling (e.g., SOCS1 and SOCS3). Using STAT3-deficient VST/BW cells, we show that STAT3 expression is required for OSM to regulate the effects of IFNγ in βhCG and E-cadherin expression. In contrast, OSM retains its modulatory effect on GM-CSF-STAT5 pathway activation even in STAT3-deficient VST/BW cells, suggesting that OSM uses STAT3-dependent and -independent mechanisms to modulate the activation of pro-inflammatory pathways IFNγ-STAT1 and GM-CSF-STAT5. Moreover, STAT3 deficiency in VST/BW cells leads to the production of both a large amount of βhCG and an enhanced expression of activated STAT5 induced by GM-CSF, independently of OSM, suggesting a key role for STAT3 in βhCG production and trophoblast differentiation through STAT5 modulation. In conclusion, our study describes for the first time the critical role played by OSM and STAT3 signaling pathways to preserve and regulate trophoblast biological functions during inflammatory stress.

Advanced magnetic resonance imaging detects altered placental development in pregnancies affected by congenital heart disease

Congenital heart disease (CHD) is the most common congenital malformation and is associated with adverse neurodevelopmental outcomes. The placenta is crucial for healthy fetal development and placental development is altered in pregnancy when the fetus has CHD. This study utilized advanced combined diffusion-relaxation MRI and a data-driven analysis technique to test the hypothesis that placental microstructure and perfusion are altered in CHD-affected pregnancies. 48 participants (36 controls, 12 CHD) underwent 67 MRI scans (50 control, 17 CHD). Significant differences in the weighting of two independent placental and uterine-wall tissue components were identified between the CHD and control groups (both pFDR<0.001), with changes most evident after 30 weeks gestation. A Significant trend over gestation in weighting for a third independent tissue component was also observed in the CHD cohort (R = 0.50, pFDR=0.04), but not in controls. These findings add to existing evidence that placental development is altered in CHD. The results may reflect alterations in placental perfusion or the changes in fetal-placental flow, villous structure and maturation that occur in CHD. Further research is needed to validate and better understand these findings and to understand the relationship between placental development, CHD, and its neurodevelopmental implications.

Sex-based disparities in DNA methylation and gene expression in late-gestation mouse placentas

BACKGROUND

The placenta is vital for fetal development and its contributions to various developmental issues, such as pregnancy complications, fetal growth restriction, and maternal exposure, have been extensively studied in mice. The placenta forms mainly from fetal tissue and therefore has the same biological sex as the fetus it supports. Extensive research has delved into the placenta's involvement in pregnancy complications and future offspring development, with a notable emphasis on exploring sex-specific disparities. However, despite these investigations, sex-based disparities in epigenetic (e.g., DNA methylation) and transcriptomic features of the late-gestation mouse placenta remain largely unknown.

METHODS

We collected male and female mouse placentas at late gestation (E18.5, n = 3/sex) and performed next-generation sequencing to identify genome-wide sex differences in transcription and DNA methylation.

RESULTS

Our comparison between male and female revealed 358 differentially expressed genes (DEGs) on autosomes, which were associated with signaling pathways involved in transmembrane transport and the responses to viruses and external stimuli. X chromosome DEGs (n = 39) were associated with different pathways, including those regulating chromatin modification and small GTPase-mediated signal transduction. Differentially methylated regions (DMRs) were more common on the X chromosomes (n = 3756) than on autosomes (n = 1705). Interestingly, while most X chromosome DMRs had higher DNA methylation levels in female placentas and tended to be included in CpG dinucleotide-rich regions, 73% of autosomal DMRs had higher methylation levels in male placentas and were distant from CpG-rich regions. Several DEGs were correlated with DMRs. A subset of the DMRs present in late-stage placentas were already established in mid-gestation (E10.5) placentas (n = 348 DMRs on X chromosome and 19 DMRs on autosomes), while others were acquired later in placental development.

CONCLUSION

Our study provides comprehensive lists of DEGs and DMRs between male and female that collectively cause profound differences in the DNA methylation and gene expression profiles of late-gestation mouse placentas. Our results demonstrate the importance of incorporating sex-specific analyses into epigenetic and transcription studies to enhance the accuracy and comprehensiveness of their conclusions and help address the significant knowledge gap regarding how sex differences influence placental function.

Analysis of histone H3K4me3 modifications in bovine placenta derived from different calf-production methods

In ruminants, the overgrowth of offspring produced by in vitro fertilization (IVF) is a common problem. Abnormal epigenetic modifications caused by environmental factors during the early embryonic period are suspected as an aetiology of overgrowth. In this study, we investigated the genome-wide histone H3K4me3 profiles of bovine placentae that play a pivotal role in foetal development and compared their characteristics between artificial insemination (AI)- and IVF-derived samples. Cotyledons were harvested from the placentae obtained at parturition of 5 AI- and 13 IVF-derived calves, and chromatin immunoprecipitation sequencing was performed for H3K4me3. We confirmed no significant maternal tissue contamination in the samples we used. The revealed H3K4me3 profiles reflected the general characteristics of the H3K4me3 modification, which is abundantly distributed in the promoter region of active genes. By extracting common modifications from multiple samples, the genes involved in placenta-specific biological processes could be enriched. Comparison with the H3K4me3 modifications of blastocyst samples was also effective for enriching the placenta-specific features. Principal component analysis suggested the presence of differential H3K4me3 modifications in AI- and IVF-derived samples. The genes contributing to the difference were related to the developmental biological processes. Imprinted genes such as BEGAIN, ZNF215 and DLX5 were among the extracted genes. Principal component and discriminant analyses using only male samples categorized the samples into three groups based on foetal weight and calf-production methods. To our knowledge, this is the first study to profile the genome-wide histone modifications of bovine foetal placentae and reveal their differential characteristics between different calf-production methods.

Quantification of Trophoblast Syncytialization by Fluorescent Membrane Labeling

Trophoblast fusion or syncytialization is a fundamental yet poorly understood process during placental development. Primary cultured cytotrophoblasts and human choriocarcinoma cell lines are commonly used to study trophoblast fusion mechanisms in vitro. Quantification of trophoblast fusion index is a key for the in vitro studies. In this chapter, we describe a new method to quantify fusion index, which is based on fluorescent labeling of the plasma membrane using Di-8-ANEPPS, a membrane potential dye. This method directly works on live cells, thereby is simple, economic, and reliable.

Maternal dietary patterns and placental outcomes among pregnant women in Los Angeles

INTRODUCTION

Epidemiological studies have linked prenatal maternal diet to fetal growth, but whether diet affects placental outcomes is poorly understood.

METHODS

We collected past month dietary intake from 148 women in mid-pregnancy enrolled at University of California Los Angeles (UCLA) antenatal clinics from 2016 to 2019. We employed the food frequency Diet History Questionnaire II and generated the Healthy Eating Index-2015 (HEI-2015), the Alternate Healthy Eating Index for Pregnancy (AHEI-P), and the Alternate Mediterranean Diet (aMED). We conducted T2-weighted magnetic resonance imaging (MRI) in mid-pregnancy (1st during 14-17 and 2nd during 19-24 gestational weeks) to evaluate placental volume (cm3) and we measured placenta weight (g) at delivery. We estimated change and 95 % confidence interval (CI) in placental volume and associations of placenta weight with all dietary index scores and diet items using linear regression models.

RESULTS

Placental volume in mid-pregnancy was associated with an 18.9 cm3 (95 % CI 5.1, 32.8) increase per 100 gestational days in women with a higher HEI-2015 (≥median), with stronger results for placentas of male fetuses. We estimated positive associations between placental volume at the 1st and 2nd MRI and higher intake of vegetables, high-fat fish, dairy, and dietary intake of B vitamins. A higher aMED (≥median) score was associated with a 40.5 g (95 % CI 8.5, 72.5) increase in placenta weight at delivery, which was mainly related to protein intake.

DISCUSSION

Placental growth represented by volume in mid-pregnancy and weight at birth is influenced by the quality and content of the maternal diet.