The role of the placenta in fetal nutrition and growth

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.

Epigenetics of prenatal stress in humans: the current research landscape

Fetal exposure to prenatal stress can have significant consequences on short- and long-term health. Epigenetic mechanisms, especially DNA methylation (DNAm), are a possible process how these adverse environmental events could be biologically embedded. We evaluated candidate gene as well as epigenome-wide association studies associating prenatal stress and DNAm changes in peripheral tissues; however, most of these findings lack robust replication. Prenatal stress-associated epigenetic changes have also been linked to child health including internalizing problems, neurobehavioral outcomes and stress reactivity. Future studies should focus on refined measurement and definition of prenatal stress and its timing, ideally also incorporating genomic as well as longitudinal information. This will provide further opportunities to enhance our understanding of the biological embedding of prenatal stress exposure.

Inhibition of lipopolysaccharide-induced inflammation by trophoblast-conditioned medium and trophoblast-derived extracellular vesicles in human middle ear epithelial cells

Otitis media is a common disease but can cause severe inner ear inflammation and hearing loss if it persists for more than two weeks. This study elucidates the inflammation-inhibiting efficacy of conditioned medium (CM) and extracellular vesicles (EVs) derived from human trophoblast (TB) cells in lipopolysaccharide (LPS)-induced human middle ear epithelial cells (HMEECs). TB-conditioned medium (TB-CM) reduced the inflammatory response and regulated mucin and epithelial sodium channel genes in LPS-induced HMEECs. The underlying mechanism of cell migration during inflammatory healing in LPS-induced HMEECs treated with TB-CM was determined by RNA-sequencing analysis. Specifically, the NF-κB pathway related to the copper metabolism MURR1 domain protein was studied and verified through siRNA. This elucidation of the anti-inflammatory effect of TB-CM and TB-derived EVs demonstrates their clinical potential to treat chronic inflammation.

Elevated gestational testosterone impacts vascular and uteroplacental function

Maternal vascular adaptations to establish an adequate blood supply to the uterus and placenta are essential for optimal nutrient and oxygen delivery to the developing fetus in eutherian mammals, including humans. Numerous factors contribute to maintaining appropriate hemodynamics and placental vascular development throughout pregnancy. Failure to achieve or sustain these pregnancy-associated changes in women is strongly associated with an increased risk of antenatal complications, such as preeclampsia, a hypertensive disorder of pregnancy. The precise etiology of preeclampsia is unknown, but emerging evidence points to a potential role for androgens. The association between androgens and maternal cardiovascular and placental function merits particular attention due to the notable 2- to 3-fold elevated plasma testosterone (T) levels observed in preeclampsia. T levels in preeclamptic women positively correlate with vascular dysfunction, and preeclampsia is associated with increased androgen receptor (AR) levels in placental tissues. Moreover, animal studies replicating the pattern and magnitude of T increase observed in preeclamptic pregnancies have reproduced key features of preeclampsia, including gestational hypertension, endothelial dysfunction, heightened vasoconstriction to angiotensin II, impaired spiral artery remodeling, placental hypoxia, reduced nutrient transport, and fetal growth restriction. Collectively, these findings suggest that AR-mediated activity plays a significant role in the clinical presentation of preeclampsia. This review critically evaluates this hypothesis, considering both clinical and preclinical evidence.

Constitutive and conditional deletion reveals distinct phenotypes driven by developmental versus neurotransmitter actions of the neuropeptide PACAP

Neuropeptides may exert trophic effects during development, and then neurotransmitter roles in the developed nervous system. One way to associate peptide-deficiency phenotypes with either role is first to assess potential phenotypes in so-called constitutive knockout mice, and then proceed to specify, regionally and temporally, where and when neuropeptide expression is required to prevent these phenotypes. We have previously demonstrated that the well-known constellation of behavioral and metabolic phenotypes associated with constitutive pituitary adenylate cyclase-activating peptide (PACAP) knockout mice are accompanied by transcriptomic alterations of two types: those that distinguish the PACAP-null phenotype from wild-type (WT) in otherwise quiescent mice (cPRGs), and gene induction that occurs in response to acute environmental perturbation in WT mice that do not occur in knockout mice (aPRGs). Comparing constitutive PACAP knockout mice to a variety of temporally and regionally specific PACAP knockouts, we show that the prominent hyperlocomotor phenotype is a consequence of early loss of PACAP expression, is associated with Fos overexpression in hippocampus and basal ganglia, and that a thermoregulatory effect previously shown to be mediated by PACAP-expressing neurons of medial preoptic hypothalamus is independent of PACAP expression in those neurons in adult mice. In contrast, PACAP dependence of weight loss/hypophagia triggered by restraint stress, seen in constitutive PACAP knockout mice, is phenocopied in mice in which PACAP is deleted after neuronal differentiation. Our results imply that PACAP has a prominent role as a trophic factor early in development determining global central nervous system characteristics, and in addition a second, discrete set of functions as a neurotransmitter in the fully developed nervous system that support physiological and psychological responses to stress.

Does fetal growth restriction induce neuropathology within the developing brainstem?

Fetal growth restriction (FGR) is a complex obstetric issue describing a fetus that does not reach its genetic growth potential. The primary cause of FGR is placental dysfunction resulting in chronic fetal hypoxaemia, which in turn causes altered neurological, cardiovascular and respiratory development, some of which may be pathophysiological, particularly for neonatal life. The brainstem is the critical site of cardiovascular, respiratory and autonomic control, but there is little information describing how chronic hypoxaemia and the resulting FGR may affect brainstem neurodevelopment. This review provides an overview of the brainstem-specific consequences of acute and chronic hypoxia, and what is known in FGR. In addition, we discuss how brainstem structural alterations may impair functional control of the cardiovascular and respiratory systems. Finally, we highlight the clinical and translational findings of the potential roles of the brainstem in maintaining cardiorespiratory adaptation in the transition from fetal to neonatal life under normal conditions and in response to the pathological environment that arises during development in growth-restricted infants. This review emphasises the crucial role that the brainstem plays in mediating cardiovascular and respiratory responses during fetal and neonatal life. We assess whether chronic fetal hypoxaemia might alter structure and function of the brainstem, but this also serves to highlight knowledge gaps regarding FGR and brainstem development.

Microfluidic technology and simulation models in studying pharmacokinetics during pregnancy

Introduction: Preterm birth rates and maternal and neonatal mortality remain concerning global health issues, necessitating improved strategies for testing therapeutic compounds during pregnancy. Current 2D or 3D cell models and animal models often fail to provide data that can effectively translate into clinical trials, leading to pregnant women being excluded from drug development considerations and clinical studies. To address this limitation, we explored the utility of in silico simulation modeling and microfluidic-based organ-on-a-chip platforms to assess potential interventional agents. Methods: We developed a multi-organ feto-maternal interface on-chip (FMi-PLA-OOC) utilizing microfluidic channels to maintain intercellular interactions among seven different cell types (fetal membrane-decidua-placenta). This platform enabled the investigation of drug pharmacokinetics in vitro. Pravastatin, a model drug known for its efficacy in reducing oxidative stress and inflammation during pregnancy and currently in clinical trials, was used to test its transfer rate across both feto-maternal interfaces. The data obtained from FMi-PLA-OOC were compared with existing data from in vivo animal models and ex vivo placenta perfusion models. Additionally, we employed mechanistically based simulation software (Gastroplus®) to predict pravastatin pharmacokinetics in pregnant subjects based on validated nonpregnant drug data. Results: Pravastatin transfer across the FMi-PLA-OOC and predicted pharmacokinetics in the in silico models were found to be similar, approximately 18%. In contrast, animal models showed supraphysiologic drug accumulation in the amniotic fluid, reaching approximately 33%. Discussion: The results from this study suggest that the FMi-PLA-OOC and in silico models can serve as alternative methods for studying drug pharmacokinetics during pregnancy, providing valuable insights into drug transport and metabolism across the placenta and fetal membranes. These advanced platforms offer promising opportunities for safe, reliable, and faster testing of therapeutic compounds, potentially reducing the number of pregnant women referred to as "therapeutic orphans" due to the lack of consideration in drug development and clinical trials. By bridging the gap between preclinical studies and clinical trials, these approaches hold great promise in improving maternal and neonatal health outcomes.

Prenatal delta-9-tetrahydrocannabinol exposure is associated with changes in rhesus macaque DNA methylation enriched for autism genes

BACKGROUND

With the growing availability of cannabis and the popularization of additional routes of cannabis use beyond smoking, including edibles, the prevalence of cannabis use in pregnancy is rapidly increasing. However, the potential effects of prenatal cannabis use on fetal developmental programming remain unknown.

RESULTS

We designed this study to determine whether the use of edible cannabis during pregnancy is deleterious to the fetal and placental epigenome. Pregnant rhesus macaques consumed a daily edible containing either delta-9-tetrahydrocannabinol (THC) (2.5 mg/7 kg/day) or placebo. DNA methylation was measured in 5 tissues collected at cesarean delivery (placenta, lung, cerebellum, prefrontal cortex, and right ventricle of the heart) using the Illumina MethylationEPIC platform and filtering for probes previously validated in rhesus macaque. In utero exposure to THC was associated with differential methylation at 581 CpGs, with 573 (98%) identified in placenta. Loci differentially methylated with THC were enriched for candidate autism spectrum disorder (ASD) genes from the Simons Foundation Autism Research Initiative (SFARI) database in all tissues. The placenta demonstrated greatest SFARI gene enrichment, including genes differentially methylated in placentas from a prospective ASD study.

CONCLUSIONS

Overall, our findings reveal that prenatal THC exposure alters placental and fetal DNA methylation at genes involved in neurobehavioral development that may influence longer-term offspring outcomes. The data from this study add to the limited existing literature to help guide patient counseling and public health polices focused on prenatal cannabis use in the future.

Immunological tolerance in the evolution of male pregnancy

The unique male pregnancy in pipefishes and seahorses ranges from basic attachment (pouch-less species: Nerophinae) of maternal eggs to specialized internal gestation in pouched species (e.g. Syngnathus and Hippocampus) with many transitions in between. Due to this diversity, male pregnancy offers a unique platform for assessing physiological and molecular adaptations in pregnancy evolution. These insights will contribute to answering long-standing questions of why and how pregnancy evolved convergently in so many vertebrate systems. To understand the molecular congruencies and disparities in male pregnancy evolution, we compared transcriptome-wide differentially expressed genes in four syngnathid species, at four pregnancy stages (nonpregnant, early, late and parturition). Across all species and pregnancy forms, metabolic processes and immune dynamics defined pregnancy stages, especially pouched species shared expression features akin to female pregnancy. The observed downregulation of adaptive immune genes in early-stage pregnancy and its reversed upregulation during late/parturition in pouched species, most notably in Hippocampus, combined with directionless expression in the pouch-less species, suggests immune modulation to be restricted to pouched species that evolved placenta-like systems. We propose that increased foeto-paternal intimacy in pouched syngnathids commands immune suppression processes in early gestation, and that the elevated immune response during parturition coincides with pouch opening and reduced progeny reliance. Immune response regulation in pouched species supports the recently described functional MHC II pathway loss as critical in male pregnancy evolution. The independent co-option of similar genes and pathways both in male and female pregnancy highlights immune modulation as crucial for the evolutionary establishment of pregnancy.

Nutrition and Immunity in Perinatal Hypoxic-Ischemic Injury

Perinatal hypoxia ischaemia (PHI), acute and chronic, may be associated with considerable adverse outcomes in the foetus and neonate. The molecular and cellular mechanisms of injury and repair associated with PHI in the perinate are not completely understood. Increasing evidence is mounting for the role of nutrients and bioactive food components in immune development, function and repair in PHI. In this review, we explore current concepts around the neonatal immune response to PHI with a specific emphasis on the impact of nutrition in the mother, foetus and neonate.

Maternal and fetal tissue distribution of α-cypermethrin and permethrin in pregnant CD-1 mice

Pyrethroid insecticides are widely used throughout agriculture and household products. Recent studies suggest that prenatal exposure to these insecticides may adversely affect fetal development; however, little is known about the distribution of these chemicals in pregnant animals. The present study aimed to address this gap in knowledge by investigating the distribution of two commonly used pyrethroid insecticides, permethrin and α-cypermethrin, in maternal and fetal tissues of pregnant CD-1 mice. Dams were dosed from gestational days 6 to 16 via oral gavage with permethrin (1.5, 15, and 50 mg/kg), α-cypermethrin (0.3, 3, and 10 mg/kg), or corn oil vehicle. Pyrethroid levels were determined in gestational day 16 tissues collected 90 min after the final dose was administered. Across maternal tissues, levels of both pyrethroids were the highest in maternal ovaries, followed by liver and brain, respectively. In addition, levels of both pyrethroids in maternal tissues and placenta were significantly higher than those in the fetal body and amniotic fluid, suggesting that these compounds may exhibit low transfer across the mouse placenta. While additional toxicokinetic studies are needed to verify the time course of pyrethroids in the fetal compartment, these findings support investigation into indirect modes of action relevant to the effects of pyrethroids on mammalian fetal development.

Maternal Prenatal Stress, Thyroid Function and Neurodevelopment of the Offspring: A Mini Review of the Literature

Fetal brain is extremely plastic and vulnerable to environmental influences that may have long-term impact on health and development of the offspring. Both the Hypothalamic-Pituitary-Adrenal (HPA) and the Hypothalamic-Pituitary-Thyroid (HPT) axes are involved in stress responses, whereas, their final effectors, the Glucocorticoids (GCs) and the Thyroid Hormones (TH s), mediate several fundamental processes involved in neurodevelopment. The effects of these hormones on brain development are found to be time and dose-dependent. Regarding THs, the developing fetus depends on maternal supply of hormones, especially in the first half of pregnancy. It is acknowledged that inadequate or excess concentrations of both GCs and THs can separately cause abnormalities in the neuronal and glial structures and functions, with subsequent detrimental effects on postnatal neurocognitive function. Studies are focused on the direct impact of maternal stress and GC excess on growth and neurodevelopment of the offspring. Of particular interest, as results from recent literature data, is building understanding on how chronic stress and alterations of the HPA axis interacts and influences HPT axis and TH production. Animal studies have shown that increased GC concentrations related to maternal stress, most likely reduce maternal and thus fetal circulating THs, either directly or through modifications in the expression of placental enzymes responsible for regulating hormone levels in fetal microenvironment. The purpose of this review is to provide an update on data regarding maternal stress and its impact on fetal neurodevelopment, giving particular emphasis in the interaction of two axes and the subsequent thyroid dysfunction resulting from such circumstances.

Hypoxia-Induced Alpha-Globin Expression in Syncytiotrophoblasts Mimics the Pattern Observed in Preeclamptic Placentas

Preeclampsia (PE) is a pregnancy disorder associated with placental dysfunction and elevated fetal hemoglobin (HbF). Early in pregnancy the placenta harbors hematopoietic stem and progenitor cells (HSPCs) and is an extramedullary source of erythropoiesis. However, globin expression is not unique to erythroid cells and can be triggered by hypoxia. To investigate the role of the placenta in increasing globin levels previously reported in PE, flow cytometry, histological and immunostaining and in situ analyses were used on placenta samples and ex vivo explant cultures. Our results indicated that in PE pregnancies, placental HSPC homing and erythropoiesis were not affected. Non-erythroid alpha-globin mRNA and protein, but not gamma-globin, were detected in syncytiotrophoblasts and stroma of PE placenta samples. Similarly, alpha-globin protein and mRNA were upregulated in normal placenta explants cultured in hypoxia. The upregulation was independent of HIF1 and NRF2, the two main candidates of globin transcription in non-erythroid cells. Our study is the first to demonstrate alpha-globin mRNA expression in syncytiotrophoblasts in PE, induced by hypoxia. However, gamma-globin was only expressed in erythrocytes. We conclude that alpha-globin, but not HbF, is expressed in placental syncytiotrophoblasts in PE and may contribute to the pathology of the disease.

Transient systemic inflammation in adult male mice results in underweight progeny

PROBLEM

While the testes represent an immune-privileged organ, there is evidence that systemic inflammation is accompanied by local inflammatory responses. We therefore examined whether transient systemic inflammation caused any inflammatory and functional consequences in murine testes.

METHOD OF STUDY

Using a single systemic administration of Toll-like receptor (TLR) agonists [lipopolysaccharide (LPS) or peptidoglycan (PG) or polyinosinic-polycytidylic acid (polyIC)] in young adult male mice, we assessed testicular immune-inflammatory landscape and reproductive functionality.

RESULTS

Our findings demonstrated a significant induction of testicular TNF-α, IL-1β and IL-6 transcripts within 24 h of TLR agonist injection. By day 6, these cytokine levels returned to baseline. While there was no change in caudal sperm counts at early time points, eight weeks later, twofold decrease in sperm count and reduced testicular testosterone levels were evident. When these mice were subjected to mating studies, no differences in mating efficiencies or litter sizes were observed compared with controls. Nonetheless, the neonatal weights of progeny from LPS/PG/polyIC-treated sires were significantly lower than controls. Postnatal weight gain up to three weeks was also slower in the progeny of LPS/polyIC-treated sires. Placental weights at 17.5 days post-coitum were significantly lower in females mated to LPS- and polyIC-treated males. Given this likelihood of an epigenetic effect, we found lower testicular levels of histone methyltransferase enzyme, mixed-lineage leukaemia-1, in mice given LPS/PG/polyIC 8 weeks earlier.

CONCLUSION

Exposure to transient systemic inflammation leads to transient local inflammation in the testes, with persistent sperm-mediated consequences for foetal development.

Occupational exposure to pesticides in female tea garden workers and adverse birth outcomes

Pesticides are globally used to eliminate pests from crops and plants. The increased use of pesticides has posed a serious threat to human health. This study evaluates the effects of pesticide exposure on pregnancy outcomes in tea garden workers (TGW). The acetylcholinesterase (AChE) activity was measured in the maternal blood, placenta, and cord blood of TGW and housewives (HWs). The placental structure and expression of hypoxia-inducible factor (HIF)-1α were also analyzed in TGW and HW groups delivering low birth weight (LBW) and normal birth weight (NBW) babies. A significantly decreased AChE activity was observed in maternal blood and cord blood in TGW as compared with HW in the LBW group. However, it did not change significantly in the NBW group (p < .05). The adjusted regression analysis of birth outcomes (birth weight, head circumference, infant's length, and ponderal index) revealed a significant and positive association with the levels of AChE activity in maternal blood, placenta, and cord blood in TGW (p < .05). The histological analysis showed significantly higher placental syncytial knots, chorangiosis, fibrinoid deposition, necrosis, and stromal fibrosis in the LBW group of TGW. Microinfarction, increased fibrinoid deposition, and atypical villi characteristics, such as mushroom-like structures, were observed during scanning electron microscopy along with increased HIF-1α expression in placental tissues of TGW exposed to pesticides. Results suggest that occupational pesticide exposure during pregnancy may decrease AChE activity and cause in utero pathological changes accompanied by an increased HIF-1α expression, which also contributes to placental insufficiency and fetal growth restriction.

Microphysiological systems of the placental barrier

Methods to evaluate maternal-fetal transport across the placental barrier have generally involved clinical observations after-the-fact, ex vivo perfused placenta studies, or in vitro Transwell assays. Given the ethical and technical limitations in these approaches, and the drive to understand fetal development through the lens of transport-induced injury, such as with the examples of thalidomide and Zika Virus, efforts to develop novel approaches to study these phenomena have expanded in recent years. Notably, within the past 10 years, placental barrier models have been developed using hydrogel, bioreactor, organ-on-a-chip, and bioprinting approaches. In this review, we discuss the biology of the placental barrier and endeavors to recapitulate this barrier in vitro using these approaches. We also provide analysis of current limitations to drug discovery in this context, and end with a future outlook.

Testosterone Decreases Placental Mitochondrial Content and Cellular Bioenergetics

Placental mitochondrial dysfunction plays a central role in the pathogenesis of preeclampsia. Since preeclampsia is a hyperandrogenic state, we hypothesized that elevated maternal testosterone levels induce damage to placental mitochondria and decrease bioenergetic profiles. To test this hypothesis, pregnant Sprague–Dawley rats were injected with vehicle or testosterone propionate (0.5 mg/kg/day) from gestation day (GD) 15 to 19. On GD20, the placentas were isolated to assess mitochondrial structure, copy number, ATP/ADP ratio, and biogenesis (Pgc-1α and Nrf1). In addition, in vitro cultures of human trophoblasts (HTR-8/SVneo) were treated with dihydrotestosterone (0.3, 1.0, and 3.0 nM), and bioenergetic profiles using seahorse analyzer were assessed. Testosterone exposure in pregnant rats led to a 2-fold increase in plasma testosterone levels with an associated decrease in placental and fetal weights compared with controls. Elevated maternal testosterone levels induced structural damage to the placental mitochondria and decreased mitochondrial copy number. The ATP/ADP ratio was reduced with a parallel decrease in the mRNA and protein expression of Pgc-1α and Nrf1 in the placenta of testosterone-treated rats compared with controls. In cultured trophoblasts, dihydrotestosterone decreased the mitochondrial copy number and reduced PGC-1α, NRF1 mRNA, and protein levels without altering the expression of mitochondrial fission/fusion genes. Dihydrotestosterone exposure induced significant mitochondrial energy deficits with a dose-dependent decrease in basal respiration, ATP-linked respiration, maximal respiration, and spare respiratory capacity. In summary, our study suggests that the placental mitochondrial dysfunction induced by elevated maternal testosterone might be a potential mechanism linking preeclampsia to feto-placental growth restriction.

Protein Profile Changes in Circulating Placental Extracellular Vesicles in Term and Preterm Births: A Longitudinal Study

Spontaneous preterm birth (PTB) is a major obstetrical problem around the globe and the mechanisms leading to PTB are unclear. Recently, changes in the circulating levels of placental extracellular vesicles (EVs) during pregnancy have been associated with various pregnancy complications. However, progress in the field is hindered by the inability to isolate placental EVs from the maternal circulation. A longitudinal study design was used to determine the protein cargo present in circulating placental EVs in maternal plasma of term and PTB across gestation (ie, first, second, and third trimester). Placental-derived EVs were enriched from the total EV population based on their expression of membrane-bound placental alkaline phosphatase (PLAP). A quantitative, information-independent acquisition (sequential windowed acquisition of all theoretical mass spectra [SWATH]) approach identified and quantified the placental EV protein contents. PLAP+ EVs did not change in characteristics (size, shape, and markers) but did differ in numbers across gestation with low levels in PTB. A comparison analysis between the PLAP+ EV proteome from term and PTB revealed 96 proteins differing significantly (P < 0.05, false discovery rate 1%) across gestation. Bioinformatics analysis of differentially expressed proteins revealed consistent upregulation of inflammatory pathways in both upregulation of epithelial mesenchymal transition pathways at term and downregulation of coagulation/complement activation in preterm. Characterization of the proteomic profile in PLAP+ EVs across gestation demonstrates dramatic changes, which might be used to understand the biological process associated with early parturition and develop biomarkers for predicting high-risk status for PTB.

Differential and overlapping targets of the transcriptional regulators NRF1, NRF2, and NRF3 in human cells

The nuclear factor (erythroid 2)-like (NRF) transcription factors are a subset of cap'n'collar transcriptional regulators. They consist of three members, NRF1, NRF2, and NRF3, that regulate the expression of genes containing antioxidant-response elements (AREs) in their promoter regions. Although all NRF members regulate ARE-containing genes, each is associated with distinct roles. A comprehensive study of differential and overlapping DNA-binding and transcriptional activities of the NRFs has not yet been conducted. Here, we performed chromatin immunoprecipitation (ChIP)-exo sequencing, an approach that combines ChIP with exonuclease treatment to pinpoint regulatory elements in DNA with high precision, in conjunction with RNA-sequencing to define the transcriptional targets of each NRF member. Our approach, done in three U2OS cell lines, identified 31 genes that were regulated by all three NRF members, 27 that were regulated similarly by all three, and four genes that were differentially regulated by at least one NRF member. We also found genes that were up- or down-regulated by only one NRF member, with 84, 84, and 22 genes that were regulated by NRF1, NRF2, and NRF3, respectively. Analysis of the ARE motifs identified in ChIP peaks revealed that NRF2 prefers binding to AREs flanked by GC-rich regions and that NRF1 prefers AT-rich flanking regions. Thus, sequence preference, likely in combination with upstream signaling events, determines NRF member activation under specific cellular contexts. Our analysis provides a comprehensive description of differential and overlapping gene regulation by the transcriptional regulators NRF1, NRF2, and NRF3.

Cellular stress mechanisms of prenatal maternal stress: Heat shock factors and oxidative stress

Development of the brain prenatally is affected by maternal experience and exposure. Prenatal maternal psychological stress changes brain development and results in increased risk for neuropsychiatric disorders. In this review, multiple levels of prenatal stress mechanisms (offspring brain, placenta, and maternal physiology) are discussed and their intersection with cellular stress mechanisms explicated. Heat shock factors and oxidative stress are closely related to each other and converge with the inflammation, hormones, and cellular development that have been more deeply explored as the basis of prenatal stress risk. Increasing evidence implicates cellular stress mechanisms in neuropsychiatric disorders associated with prenatal stress including affective disorders, schizophrenia, and child-onset psychiatric disorders. Heat shock factors and oxidative stress also have links with the mechanisms involved in other kinds of prenatal stress including external exposures such as environmental toxicants and internal disruptions such as preeclampsia. Integrative understanding of developmental neurobiology with these cellular and physiological mechanisms is necessary to reduce risks and promote healthy brain development.

Extra Purified Exosomes from Human Placenta Contain An Unpredictable Small Number of Different Major Proteins

Exosomes are nanovesicles (30-100 nm) containing various RNAs and different proteins. Exosomes are important in intracellular communication, immune function, etc. Exosomes from different sources including placenta were mainly obtained by different types of centrifugation and ultracentrifugations and were reported to contain from a few dozen to thousands of different proteins. First crude exosome preparations from four placentas (normal pregnancy) were obtained here using several standard centrifugations but then were additionally purified by gel filtration on Sepharose 4B. Individual preparations demonstrated different gel filtration profiles showing good or bad separation of exosome peaks from two peaks of impurity proteins and their complexes. According to electron microscopy, exosomes before gel filtration contain vesicles of different size, ring-shaped structures forming by ferritin and clusters of aggregated proteins and their complexes. After filtration through 220 nm filters and gel filtration exosomes display typically for exosome morphology and size (30-100 nm) and do not contain visible protein admixtures. Identification of exosome proteins was carried out by MS and MS/MS MALDI mass spectrometry of proteins' tryptic hydrolyzates after their SDS-PAGE and 2D electrophoresis. We have obtained unexpected results. Good, purified exosomes contained only 11-13 different proteins: CD9, CD81, CD-63, hemoglobin subunits, interleukin-1 receptor, annexin A1, annexin A2, annexin A5, cytoplasmic actin, alkaline phosphatase, serotransferin, and probably human serum albumin and immunoglobulins. We assume that a possible number of exosome proteins found previously using crude preparations may be very much overestimated. Our data may be important for study of biological functions of pure exosomes.

Exosomes from human placenta purified by affinity chromatography on sepharose bearing immobilized antibodies against CD81 tetraspanin contain many peptides and small proteins

Exosomes are nanovesicles (40-100 nm) containing various RNAs and different proteins. Exosomes are involved in intracellular communication and immune system function. Exosomes from different sources are usually isolated using standard methods-centrifugation and ultracentrifugations. Exosomes isolated by these procedures were reported to contain from a few dozen to thousands of different proteins. Here crude vesicle preparations from five placentas (normal pregnancy) were first obtained using standard centrifugation procedures. According to electron-microscopic studies, these preparations contained vesicles of different size (30-225 nm), particles of round shape of average electron density ("nonvesicles" 20-40 nm) (A), structured clusters of associated proteins and shapeless aggregations (B), as well as ring-shaped 10-14 nm structures formed by ferritin (C). After additional purification of the vesicle preparations by gel filtration on Sepharose 4B, the main part of protein structures was removed; however, the preparations still contained small admixtures of components A-C. Further purification of the preparations by affinity chromatography on Sepharose bearing immobilized antibodies against exosome surface protein CD81 led to isolation of highly purified exosomes (40-100 nm). These exosomes according to electron microscopy data contained tetraspanin embedded in the membrane, which was stained with antibodies against CD81 conjugated with 10-12 nm gold nanoparticles. SDS-PAGE and MALDI MS and MS/MS mass spectrometry of tryptic hydrolysates of proteins contained in these exosomes revealed eleven major proteins (>10 kDa): hemoglobin subunits, CD81, interleukin-1 receptor, annexin A5, cytoplasmic actin, alpha-actin-4, alkaline phosphatase, human serum albumin, serotransferrin, and lactotrasferrin. Using MALDI mass analysis of the highly purified exosomes, we for the first time found that in addition to the large proteins (>10 kDa), exosomes having affinity to CD81 contain more than 27 different peptides and small proteins of 2-10 kDa. This finding can be useful for revealing biological functions of pure exosomes. © 2018 IUBMB Life, 70(11):1144-1155, 2018.

The DNA-hydrolyzing activity of IgG antibodies from human placenta

OBJECTIVE

Since during pregnancy and lactation women tend to develop autoimmune processes, characterization of placenta immunoglobulins and their possible catalytic functions is a very important step towards understanding the function of placenta.

METHODS

ELISA, affinity chromatography, SDS-PAGE and MALDI mass spectrometry were used.

RESULTS

It was shown, that ten placentas contain in average 1.1 ± 0.33 mg IgGs/g of placenta and 0.11 ± 0.1 mЕ anti-DNA antibodies/g of placenta. All ten individual IgG preparations were characterized by a specific ratio and various combinations of heavy (47.5-51.7 kDa) and light (22.2-33.3 kDa) chains with different molecular masses. All intact IgGs demonstrate DNase but have not amylase activity. Several strict criteria have been used to show that the DNase activity is an intrinsic property of placenta IgGs. The heavy chains of antibodies were catalytically inactive. The light chains of 22-24 kDa of all IgGs demonstrated maximal DNase activity, while the chains of approximately 25-33.2 kDa were significantly less active. IgGs were completely inactive after dialysis against EDTA. The optimal external cofactors of placenta DNase abzymes are Mg²⁺ and Cu²⁺ ions, while, activity in the presence of Mn²⁺ and Ca²⁺ is approximately 3-4-fold lower. Activation of DNase abzymes by Cu²⁺ ions was revealed for the first time. Placental antibodies possess selective cytotoxicity against cancer cells.

CONCLUSION

It was shown previously, that appearance of serum DNase abzymes is the good indicator of the beginning and obvious spontaneous or induced autoimmune diseases. The detection of placenta DNase antibodies indicates that during pregnancy, autoimmune processes can affect this organ.

Fetal hemoglobin in umbilical cord blood in preeclamptic and normotensive pregnancies: A cross-sectional comparative study

Preeclampsia (PE) is associated with increased fetal hemoglobin (HbF) in the maternal circulation but its source is unknown. To investigate whether excessive HbF is produced in the placenta or the fetus, the concentration of HbF (cHbF) in the arterial and venous umbilical cord blood (UCB) was compared in 15825 normotensive and 444 PE pregnancies. The effect of fetal gender on cHbF was also evaluated in both groups. Arterial and venous UCB sampled immediately after birth at 36-42 weeks of gestation were analyzed for total Hb concentration (ctHb) (g/L) and HbF% using a Radiometer blood gas analyzer. Non-parametric tests were used for statistical comparison and P values < 0.05 were considered significant. Our results indicated higher cHbF in venous compared to arterial UCB in both normotensive (118.90 vs 117.30) and PE (126.75 vs 120.12) groups. In PE compared to normotensive pregnancies, a significant increase was observed in arterial and venous ctHb (171.00 vs 166.00 and 168.00 vs 163.00, respectively) while cHbF was only significantly increased in venous UCB (126.75 vs 118.90). The pattern was similar in both genders. These results indicate a substantial placental contribution to HbF levels in UCB, which increases in PE and is independent of fetal gender, suggesting the elevated cHbF evident in PE results from placental dysfunction.

Beyond individualism: Is there a place for relational autonomy in clinical practice and research?

The dominant, individualistic understanding of autonomy that features in clinical practice and research is underpinned by the idea that people are, in their ideal form, independent, self-interested and rational gain-maximising decision-makers. In recent decades, this paradigm has been challenged from various disciplinary and intellectual directions. Proponents of ‘relational autonomy’ in particular have argued that people’s identities, needs, interests – and indeed autonomy – are always also shaped by their relations to others. Yet, despite the pronounced and nuanced critique directed at an individualistic understanding of autonomy, this critique has had very little effect on ethical and legal instruments in clinical practice and research so far. In this article, we use four case studies to explore to what extent, if at all, relational autonomy can provide solutions to ethical and practical problems in clinical practice and research. We conclude that certain forms of relational autonomy can have a tangible and positive impact on clinical practice and research. These solutions leave the ultimate decision to the person most affected, but encourage and facilitate the consideration of this person’s care and responsibility for connected others.

An effective placental cotyledons proteins extraction method for 2D gel electrophoresis

Effective protein extraction is essential especially in producing a well-resolved proteome on 2D gels. A well-resolved placental cotyledon proteome, with good reproducibility, have allowed researchers to study the proteins underlying the physiology and pathophysiology of pregnancy. The aim of this study is to determine the best protein extraction protocol for the extraction of protein from placental cotyledons tissues for a two-dimensional gel electrophoresis (2D-GE). Based on widely used protein extraction strategies, 12 different extraction methodologies were carefully selected, which included one chemical extraction, two mechanical extraction coupled protein precipitations, and nine chemical extraction coupled protein precipitations. Extracted proteins were resolved in a one-dimensional gel electrophoresis and 2D-GE; then, it was compared with set criteria: extraction efficacy, protein resolution, reproducibility, and recovery efficiency. Our results revealed that a better profile was obtained by chemical extraction in comparison to mechanical extraction. We further compared chemical extraction coupled protein precipitation methodologies, where the DNase/lithium chloride-dense sucrose homogenization coupled dichloromethane-methanol precipitation (DNase/LiCl-DSH-D/MPE) method showed good protein extraction efficiency. This, however, was carried out with the best protein resolution and proteome reproducibility on 2D-gels. DNase/LiCl-DSH-D/MPE was efficient in the extraction of proteins from placental cotyledons tissues. In addition, this methodology could hypothetically allow the protein extraction of any tissue that contains highly abundant lipid and glycogen.

Marsupial tammar wallaby delivers milk bioactives to altricial pouch young to support lung development

Our research is exploiting the marsupial as a model to understand the signals required for lung development. Marsupials have a unique reproductive strategy, the mother gives birth to altricial neonate with an immature lung and the changes in milk composition during lactation in marsupials appears to provide bioactives that can regulate diverse aspects of lung development, including branching morphogenesis, cell proliferation and cell differentiation. These effects are seen with milk collected between 25 and 100days postpartum. To better understand the temporal effects of milk composition on postnatal lung development we used a cross-fostering technique to restrict the tammar pouch young to milk composition not extending beyond day 25 for 45days of its early postnatal life. These particular time points were selected as our previous study showed that milk protein collected prior to ~day 25 had no developmental effect on mouse embryonic lungs in culture. The comparative analysis of the foster group and control young at day 45 postpartum demonstrated that foster pouch young had significantly reduced lung size. The lungs in fostered young were comprised of large intermediate tissue, had a reduced size of airway lumen and a higher percentage of parenchymal tissue. In addition, expression of marker genes for lung development (BMP4, WNT11, AQP-4, HOPX and SPB) were significantly reduced in lungs from fostered young. Further, to identify the potential bioactive expressed by mammary gland that may have developmental effect on pouch young lungs, we performed proteomics analysis on tammar milk through mass-spectrometry and listed the potential bioactives (PDGF, IGFBP5, IGFBPL1 and EGFL6) secreted in milk that may be involved in regulating pouch young lung development. The data suggest that postnatal lung development in the tammar young is most likely regulated by maternal signalling factors supplied through milk.

Therapeutically targeting mitochondrial redox signalling alleviates endothelial dysfunction in preeclampsia

Aberrant placentation generating placental oxidative stress is proposed to play a critical role in the pathophysiology of preeclampsia. Unfortunately, therapeutic trials of antioxidants have been uniformly disappointing. There is provisional evidence implicating mitochondrial dysfunction as a source of oxidative stress in preeclampsia. Here we provide evidence that mitochondrial reactive oxygen species mediates endothelial dysfunction and establish that directly targeting mitochondrial scavenging may provide a protective role. Human umbilical vein endothelial cells exposed to 3% plasma from women with pregnancies complicated by preeclampsia resulted in a significant decrease in mitochondrial function with a subsequent significant increase in mitochondrial superoxide generation compared to cells exposed to plasma from women with uncomplicated pregnancies. Real-time PCR analysis showed increased expression of inflammatory markers TNF-α, TLR-9 and ICAM-1 respectively in endothelial cells treated with preeclampsia plasma. MitoTempo is a mitochondrial-targeted antioxidant, pre-treatment of cells with MitoTempo protected against hydrogen peroxide-induced cell death. Furthermore MitoTempo significantly reduced mitochondrial superoxide production in cells exposed to preeclampsia plasma by normalising mitochondrial metabolism. MitoTempo significantly altered the inflammatory profile of plasma treated cells. These novel data support a functional role for mitochondrial redox signaling in modulating the pathogenesis of preeclampsia and identifies mitochondrial-targeted antioxidants as potential therapeutic candidates.

Overexpression of G0/G1 Switch Gene 2 in Adipose Tissue of Transgenic Quail Inhibits Lipolysis Associated with Egg Laying

In avians, yolk synthesis is regulated by incorporation of portomicrons from the diet, transport of lipoproteins from the liver, and release of lipids from adipose tissue; however, the extent to which lipolysis in adipose tissue contributes to yolk synthesis and egg production has yet to be elucidated. G0/G1 switch gene 2 (G0S2) is known to bind and inhibit adipose triglyceride lipase (ATGL), the rate-limiting enzyme in lipolysis. The objective of this study was to determine whether overexpression of the G0S2 gene in adipose tissue could successfully inhibit endogenous ATGL activity associated with egg laying. Two independent lines of transgenic quail overexpressing G0S2 had delayed onset of egg production and reduced number of eggs over a six-week period compared to non-transgenic quail. Although no differences in measured parameters were observed at the pre-laying stage (5 weeks of age), G0S2 transgenic quail had significantly larger interclavicular fat pad weights and adipocyte sizes and lower NEFA concentrations in the serum at early (1 week after laying first egg) and active laying (5 weeks after laying first egg) stages. Overexpression of G0S2 inhibited lipolysis during early and active laying, which drastically shifted the balance towards a net accumulation of triacylglycerols and increased adipose tissue mass. Thereby, egg production was negatively affected as less triacylglycerols were catabolized to produce lipids for the yolk.

Lentivirus-mediated PHLDA2 overexpression inhibits trophoblast proliferation, migration and invasion, and induces apoptosis

Inadequate trophoblast invasion and increased trophoblast apoptosis cause serious pregnancy complications. Pleckstrin homology-like domain, family A, member 2 (PHLDA2) has been linked to fetal size at birth and growth restriction in a number of studies. However, the impact of PHLDA2 on trophoblast function had not been studied previously, to the best of our knowledge. In the present study, immunofluorescence staining demonstrated that primary trophoblasts isolated from placental villous tissues were positive for cytokeratin 18 (CK18), vimentin and human placental lactogen (hPL). JEG-3 cells and primary trophoblasts were infected with lentivirus overexpressing PHLDA2. RT-qPCR and western blot analysis detected high levels of PHLDA2. A Cell Counting Kit-8 (CCK-8) assay showed that PHLDA2 overexpression inhibited trophoblast proliferation. In addition, PHLDA2 significantly induced apoptosis, as evidenced by Annexin V-FITC/propidium iodide (PI) and Hoechst staining, along with activation of Bax and caspase-3 and also decreased Bcl-2 expression. Further investigation showed that PHLDA2 effectively induced reactive oxygen species (ROS) generation, caused cytochrome c release from the mitochondria into the cytosol and decreased mitochondrial membrane potential. PHLDA2 likely induced apoptosis through the mitochondrial pathway. Wound healing and Transwell assays indicated that PHLDA2 overexpression efficiently suppressed cell migration and invasion. These data suggest that PHLDA2 plays an important role in the occurrence and development of pregnancy complications by promoting trophoblast apoptosis and suppressing cell invasion.

Human placenta: relative content of antibodies of different classes and subclasses (IgG1-IgG4) containing lambda- and kappa-light chains and chimeric lambda-kappa-immunoglobulins

The specific organ placenta is much more than a filter: it is an organ that protects, feeds and regulates the growth of the embryo. Affinity chromatography, ELISA, SDS-PAGE and matrix-assisted laser desorption ionization mass spectrometry were used. Using 10 intact human placentas deprived of blood, a quantitative analysis of average relative content [% of total immunoglobulins (Igs)] was carried out for the first time: (92.7), IgA (2.4), IgM (2.5), kappa-antibodies (51.4), lambda-antibodies (48.6), IgG1 (47.0), IgG2 (39.5), IgG3 (8.8) and IgG4 (4.3). It was shown for the first time that placenta contains sIgA (2.5%). In the classic paradigm, Igs represent products of clonal B-cell populations, each producing antibodies recognizing a single antigen. There is a common belief that IgGs in mammalian biological fluids are monovalent molecules having stable structures and two identical antigen-binding sites. However, similarly to human milk Igs, placenta antibodies undergo extensive half-molecule exchange and the IgG pool consists of 43.5 ± 15.0% kappa-kappa-IgGs and 41.6 ± 17.0% lambda-lambda-IgGs, while 15.0 ± 4.0% of the IgGs contained both kappa- and lambda-light chains. Kappa-kappa-IgGs and lambda-lambda-IgGs contained, respectively (%): IgG1 (47.7 and 34.4), IgG2 (36.3 and 44.5), IgG3 (7.4 and 11.8) and IgG4 (7.5 and 9.1), while chimeric kappa-lambda-IgGs consisted of (%): 43.5 IgG1, 41.0 IgG2, 5.6 IgG3 and 7.9 IgG4. Our data are indicative of the possibility of half-molecule exchange between placenta IgGs of various subclasses, raised against different antigens, which explains a very well-known polyspecificity and cross-reactivity of different human IgGs.

Bioactive Functions of Milk Proteins: a Comparative Genomics Approach

The composition of milk includes factors required to provide appropriate nutrition for the growth of the neonate. However, it is now clear that milk has many functions and comprises bioactive molecules that play a central role in regulating developmental processes in the young while providing a protective function for both the suckled young and the mammary gland during the lactation cycle. Identifying these bioactives and their physiological function in eutherians can be difficult and requires extensive screening of milk components that may function to improve well-being and options for prevention and treatment of disease. New animal models with unique reproductive strategies are now becoming increasingly relevant to search for these factors.

Extremely stable soluble high molecular mass multi-protein complex with DNase activity in human placental tissue

Human placenta is an organ which protects, feeds, and regulates the grooving of the embryo. Therefore, identification and characterization of placental components including proteins and their multi-protein complexes is an important step to understanding the placenta function. We have obtained and analyzed for the first time an extremely stable multi-protein complex (SPC, ∼1000 kDa) from the soluble fraction of three human placentas. By gel filtration on Sepharose-4B, the SPC was well separated from other proteins of the placenta extract. Light scattering measurements and gel filtration showed that the SPC is stable in the presence of NaCl, MgCl2, acetonitrile, guanidinium chloride, and Triton in high concentrations, but dissociates efficiently in the presence of 8 M urea, 50 mM EDTA, and 0.5 M NaCl. Such a stable complex is unlikely to be a casual associate of different proteins. According to SDS-PAGE and MALDI mass spectrometry data, this complex contains many major glycosylated proteins with low and moderate molecular masses (MMs) 4–14 kDa and several moderately abundant (79.3, 68.5, 52.8, and 27.2 kDa) as well as minor proteins with higher MMs. The SPC treatment with dithiothreitol led to a disappearance of some protein bands and revealed proteins with lower MMs. The SPCs from three placentas efficiently hydrolyzed plasmid supercoiled DNA with comparable rates and possess at least two DNA-binding sites with different affinities for a 12-mer oligonucleotide. Progress in study of placental protein complexes can promote understanding of their biological functions.

Immunolocalization of cell cycle proteins (p57, p27, cyclin D3, PCNA and Ki67) in intrauterine growth retardation (IUGR) and normal human term placentas

Placental development involves a series of events that depend on the coordinated action of proliferation, differentiation and invasion of trophoblasts. Studies on cell cycle related proteins controlling these events are fairly limited. It is still not fully determined how placental tissue proliferation is affected by intrauterine growth retardation (IUGR). Information on cell cycle related proteins that control these events is limited and how they are affected in IUGR is not fully understood. The aim of this study was to understand the role of cell cycle regulators in IUGR placentas and to determine the spatio-temporal immunolocalization of these cell cycle regulators in human IUGR and normal term placentas. Placental samples were stained immunohistochemically with PCNA, Ki67, cyclin D3, p27 and p57 antibodies and were examined by light microscopy. In all regions of IUGR placentas, PCNA, Ki67 and cyclin D3 staining intensities were statistically significantly decreased compared to normal controls. p27 staining intensity of the IUGR group was statistically significantly increased in villous parts and chorionic plates in comparison with the normal term placentas. Moreover, p57 staining intensity was statistically significantly increased in all parts of the IUGR group compared to controls. The observed placental abnormalities in IUGR placentas may be associated with arrest mechanisms affecting cell proliferation and cell cycle alterations in IUGR.

Some preliminary matrix-assisted laser desorption/ionization imaging experiments on maternal and fetal sides of human placenta

An investigation on placenta proteins has been carried out by matrix-assisted laser desorption/ionization (MALDI) ion imaging (II) experiments. This was performed by laser irradiation of the maternal and fetal sides of placenta tissue. To investigate the possible changes in protein profile due to the development of gestational diabetes mellitus (GDM), five placenta samples from GDM patients and five placenta samples from healthy pregnant women were analyzed. An extensive optimization of the tissue slice treatment and of the matrix deposition method was performed. As already observed in MALDI spectra of placenta homogenates, and also in the MALDI-II condition, the most abundant peaks are due to hemoglobin α chain, hemoglobin β chain and hemoglobin γ chain. However, higher molecular weight protein species were detected in the m/z range 20,000-47,000. The species at m/z 30335, m/z 31235 and m/z 32000 show some differences in their abundance in the maternal and fetal sides of the tissue in both classes of subjects under investigation. Comparison with the literature data suggest that they can result from the presence of mitochondrial proteins at tissue level.

Identification and analysis of multi-protein complexes in placenta

Placental malfunction induces pregnancy disorders which contribute to life-threatening complications for both the mother and the fetus. Identification and characterization of placental multi-protein complexes is an important step to integratedly understand the protein-protein interaction networks in placenta which determine placental function. In this study, blue native/sodium dodecyl sulfate polyacrylamide gel electrophoresis (BN/SDS-PAGE) and Liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to screen the multi-protein complexes in placenta. 733 unique proteins and 34 known and novel heterooligomeric multi-protein complexes including mitochondrial respiratory chain complexes, integrin complexes, proteasome complexes, histone complex, and heat shock protein complexes were identified. A novel protein complex, which involves clathrin and small conductance calcium-activated potassium (SK) channel protein 2, was identified and validated by antibody based gel shift assay, co-immunoprecipitation and immunofluorescence staining. These results suggest that BN/SDS-PAGE, when integrated with LC-MS/MS, is a very powerful and versatile tool for the investigation of placental protein complexes. This work paves the way for deeper functional characterization of the placental protein complexes associated with pregnancy disorders.

Effect of 6-mercaptopurine on rat placenta

In order to investigate the toxic effects of 6-mercaptopurine (6-MP) on placental development, we examined sequential morphology in the placentas from rats exposed to 6-MP. 6-MP was intraperitoneally administered at 60 mg/kg during gestation days (GDs) 11 to 12, and the placentas were sampled on GD 13, 15 or 21. In the 6-MP-treated group, maternal body weight suppression, increased death embryo/fetus ratio and some malformations were observed. The placenta weights were decreased on GDs 15 and 21. Macroscopically, placentas on GD 21 were small, brittle and thin with a white peripheral rim. Histopathologically, in the labyrinth zone, 6-MP treatment mainly evoked decreased mitosis on GDs 13 and 15, increased apoptotic cell on GDs 13, 15 and 21 and thinning on GDs 15 and 21. In the basal zone, 6-MP evoked decreased mitosis on GDs 13, and PAS-positive material in the spongiotrophoblasts was still detected on GD 15. Thickening of the basal zone was observed with cytolysis of glycogen cells, apoptosis and an increased number of composed cells on GD 21. In conclusion, 6-MP administration in pregnant rats induced growth arrest of the labyrinth zone and developmental delay in the basal zone, leading to small placentas. The fetotoxicity of 6-MP may be responsible for its direct anti-proliferative effects and resulting placental dysfunction.

Placental expression of insulin-like growth factor-I, fibroblast growth factor-basic and neural cell adhesion molecule in pregnancies with small for gestational age fetuses

OBJECTIVE

To investigate placental expression of insulin-like growth factor-I (IGF-I), fibroblast growth factor-basic (FGF-b) and neural cell adhesion molecule (N-CAM) regarding the pathogenesis of pregnancies with small for gestational age (SGA) fetuses.

STUDY DESIGN

An immunohistochemical analysis using anti-IGF-I, anti-FGF-b and anti-N-CAM antibodies was carried out on 4% paraformaldehyde-fixed placental tissues of third trimester pregnancies complicated with SGA fetuses (n=12) and subjects exhibiting appropriately grown fetuses (n=10). Immunostaining patterns of chorionic villi and amniochorionic membranes were assessed.

RESULT

IGF-I, FGF-b and N-CAM immunostainings in chorionic villi demonstrated significantly increased immunoreactivities in cytotrophoblasts of SGA cases, whereas increased IGF-I immunostaining in syncitiotrophoblasts and increased N-CAM immunostaining in capillary endothelium were noted in the same group. IGF-I, FGF-b and N-CAM immunostainings in amniochorionic membranes revealed significantly decreased IGF-I immunoreactivities in extravillous trophoblasts and increased IGF-I immunoreactivities in decidual cells of SGA cases, while significantly decreased N-CAM immunoreactivities in both decidual cells and extravillous trophoblasts were noted. FGF-b immunostaining revealed no significant differences in both extravillous trophoblasts and decidual cells of SGA cases.

CONCLUSION

Increased placental expression of IGF-I, FGF-b and N-CAM may act in an autocrine and/or paracrine manner to restore the impaired trophoblastic proliferation, migration and metabolism at all gestational stages by means of a positive feedback mechanism.

Busulfan-induced apoptosis in rat placenta

In order to investigate the effects of busulfan on the placenta, we examined the sequential histopathological changes in the placenta from rats exposed to busulfan during gestation days (Days) 12-14. Busulfan was intraperitoneally administered at 10 mg/kg on Days 12, 13 and 14, and the placentas were sampled on Day 13.5, 14.5, 15, 16 or 21. Macroscopically, small placenta was seen on Day 21 with scattered white spots and white peripheral rim. Histopathologically, in the treated group, there were increased apoptosis and decreased mitotic activities in the trophoblasts of the labyrinth zone on Days 13.5, 14.5, 15 and 16. In the basal zone, slightly increased apoptosis was seen on Day 13.5 and slightly decreased mitotic activity on Day 14.5. On Day 21, the labyrinth zone in the treated group was reduced in diameter. Degeneration and necrosis of trophoblasts, a diminution in thickness of the trophoblastic septa with a deposition of calcium and an irregular dilation of the maternal blood space were scattered in the labyrinth zone, although there were no conspicuous changes in the basal zone. The anti-proliferative effects of busulfan could have inhibited the development of the labyrinth zone, and led to small placentas. The fetotoxicity and teratogenicity of busulfan might be also responsible for these placental changes.

Endocrine regulation of human fetal growth: the role of the mother, placenta, and fetus

The environment in which the fetus develops is critical for its survival and long-term health. The regulation of normal human fetal growth involves many multidirectional interactions between the mother, placenta, and fetus. The mother supplies nutrients and oxygen to the fetus via the placenta. The fetus influences the provision of maternal nutrients via the placental production of hormones that regulate maternal metabolism. The placenta is the site of exchange between mother and fetus and regulates fetal growth via the production and metabolism of growth-regulating hormones such as IGFs and glucocorticoids. Adequate trophoblast invasion in early pregnancy and increased uteroplacental blood flow ensure sufficient growth of the uterus, placenta, and fetus. The placenta may respond to fetal endocrine signals to increase transport of maternal nutrients by growth of the placenta, by activation of transport systems, and by production of placental hormones to influence maternal physiology and even behavior. There are consequences of poor fetal growth both in the short term and long term, in the form of increased mortality and morbidity. Endocrine regulation of fetal growth involves interactions between the mother, placenta, and fetus, and these effects may program long-term physiology.

Calcium Homeostasis in Human Placenta: Role of Calcium‐Handling Proteins

The human placenta is a transitory organ, representing during pregnancy the unique connection between the mother and her fetus. The syncytiotrophoblast represents the specialized unit in the placenta that is directly involved in fetal nutrition, mainly involving essential nutrients, such as lipids, amino acids, and calcium. This ion is of particular interest since it is actively transported by the placenta throughout pregnancy and is associated with many roles during intrauterine life. At term, the human fetus has accumulated about 25-30 g of calcium. This transfer allows adequate fetal growth and development, since calcium is vital for fetal skeleton mineralization and many cellular functions, such as signal transduction, neurotransmitter release, and cellular growth. Thus, there are many proteins involved in calcium homeostasis in the human placenta.

Cytotoxicant-induced trophoblast dysfunction and abnormal pregnancy outcomes: role of zinc and metallothionein

Normal trophoblast function, including implantation, hormone production, and formation of the selectively permeable maternofetal barrier, is essential for the establishment and maintenance of the fetoplacental unit and proper fetal development. Maternal cytotoxicant exposure causes the destruction of these cells, especially the terminally differentiated syncytiotrophoblasts, and results in a myriad of poor pregnancy outcomes. These outcomes range from intrauterine growth retardation and malformation to spontaneous abortion or stillbirth. There is recent evidence that the metal-binding protein, metallothionein, is involved in the protection of human trophoblastic cells from heavy metal-induced and severe oxidative stress-induced apoptosis. Metallothionein, with its unique biochemical structure, can both bind essential metal ions, such as the transcription modulator zinc, and yet allow their ready displacement by toxic nonessential metal ions or damaging free radicals. These properties suggest that metallothionein may be responsible not only for sequestering the cytotoxic agents, but also for altering signal transduction in the affected cells. Here, we review several identified causes of adverse pregnancy outcomes (specifically, prenatal exposure to cigarette smoke and alcohol, gestational infection, and exposure to environmental contaminants), discuss the role of zinc in modulating the cellular response to these toxic insults, and then propose how metallothionein may function to mediate this protective response.

Insulin and leptin do not affect fatty acid uptake and metabolism in human placental choriocarcinoma (BeWo) cells

Placental transport of long chain polyunsaturated fatty acids is important for fetal growth and development. In order to examine the effects of leptin and insulin on fatty acid uptake by the placenta, placental choriocarcinoma (BeWo) cells were used. BeWo cells were incubated for 5h at 37 degrees C in the absence or presence of different concentrations of insulin (0.6, 60, and 100 ng) or leptin (10 ng) with 200 microM of various radiolabeled fatty acids (docosahexaenoic acid, arachidonic acid, eicosapentaenoic acid, and oleic acid, mixed with 1:1 bovine serum albumin (fat free). After incubation, the uptake and distribution of these fatty acids into different cellular lipid fractions were determined. The uptakes of oleic, eicosapentaenoic, arachidonic, and docosahexaenoic acids were 15.36+/-4.1, 19.95+/-3.6, 28.56+/-8.1, and 62.25+/-9.5 nmol/mg of protein, respectively, in BeWo cells. Incubation of these cells with insulin (0.6 or 60 ng/ml) or leptin (10 ng/ml) did not significantly alter uptake of any of these fatty acids (P>0.5). Insulin or leptin also did not affect beta oxidation of fatty acids in these cells. In contrast, leptin (10 ng/ml) and insulin (0.60 ng/ml)) stimulated the uptake of oleic acid (7.4+/-2.3 nmol/mg protein) in human adipose cells, SGBS cells by 1.28- and 2.48-fold (P<0.05), respectively. The distribution of fatty acids in different cellular lipid fractions was also not affected by these hormones. Our data indicate that unlike adipose tissue, fatty acid uptake and metabolism in placental trophoblasts is not regulated by insulin or leptin.

Pituitary adenylate cyclase-activating polypeptide promotes differentiation of mouse neural stem cells into astrocytes

We have found that pituitary adenylate cyclase-activating polypeptide (PACAP) employed at the physiological concentrations induces the differentiation of mouse neural stem cells into astrocytes. The differentiation process was not affected by cAMP analogues such as dibutylic cAMP (db-cAMP) or 8Br-cAMP or by the specific competitive inhibitor of protein kinase A, Rp-adenosine-3',5'-cyclic monophosphothioate triethylamine salt (Rp-cAMP). Expression of the PACAP receptor (PAC1) in neural stem cells was detected by both RT-PCR and immunoblot using an affinity-purified antibody. The PACAP selective antagonist, PACAP(6-38), had an inhibitory effect on the PACAP-induced differentiation of neural stem cells into astrocytes. These results indicate that PACAP acts on the PAC1 receptor on the plasma membrane of mouse neural stem cells, with the signal then transmitted intracellularly via a PAC1-coupled G protein, does not involve Gs. This signaling mechanism may thus play a crucial role in the differentiation of neural stem cells into astrocytes.

Androgen secretion by Rcho-1 cells is independent of extracellular glutamate concentration

In primates, progesterone, secreted by the placenta, is important for the maintenance of pregnancy. Androstenedione, a progesterone metabolite, fulfils a similar role in the rodent. Prior work has suggested that glutamate sufficiency and subsequent oxidation is important to placental androgen synthesis, presumably because of the production of NADPH (Trophoblast Res (1993) 7, 77). Rcho-1 cells possess a phenotype similar to that of rat placental giant cells, and secrete androstenedione and progesterone when in the differentiated state (J Endocrinol (1996) 150, 161). Our objective was to determine whether extracellular glutamate concentrations impact hormone synthesis in Rcho-1 cells. Rcho-1 cells were kept in culture under differentiating conditions. Extracellular glutamate concentrations were varied from 0-5 mm, and hormone concentrations assayed by ELISA. Rcho-1 cells secreted both progesterone and androstenedione. There was no direct correlation between the extracellular concentration of glutamate and the secretion of either hormone. Inhibition of transaminases (aminooxyacetic acid) or of glutaminase (6-diazo-5-oxo-l-norleucine) did not alter hormone production. Therefore, extracellular glutamate concentrations did not impact progesterone or androstenedione secretion. These findings may relate to the central position of glutamate in a variety of metabolic pathways, making intracellular depletion of this amino acid difficult to accomplish, or may represent a species specific difference in regulation.

A maternal blood‐borne factor promotes survival of the developing thalamus

In this report, we describe the identification of a polypeptide survival-promoting factor that is produced by maternal and early postnatal peripheral blood mononuclear cells (PBMCs) of the immune system in Long-Evans rats and humans. The factor, termed Y-P30, most likely arises from proteolytic processing of a larger precursor protein and accumulates mainly in pyramidal neurons of the developing cortex and hippocampus but not in astrocytes. It was released from neurons grown in culture and substantially promotes survival of cells in explant monocultures of perinatal thalamus from the offspring. Y-P30 mRNA was not detectable in infant or adult brain and was present only in blood cells of pregnant rats and humans but not in nonpregnant controls. However, Y-P30 transcription could be induced in PBMCs of adult animals by a central nervous system lesion (i.e., optic nerve crush), which points to a potential role of the factor not only in neuronal development but also in neuroinflammation after white matter injury.

Expression of IGR-IR and VEGF and trophoblastic proliferative activity in placentas from pregnancies complicated by IUGR

Intrauterine growth retardation (IUGR) is recognized as an important cause of low birth weight and elective preterm delivery. IUGR is associated with multiple causative factors, including placental dysfunction. The aim of this prospective study was to investigate the role of trophoblastic proliferative activity and type I insuline-like growth factor receptor (IGF-IR) and vascular endothelial growth factor (VEGF) expressions in the pathogenesis of IUGR. Immunohistochemistry using VEGF, IGF-IR, and Ki-67 antibodies was performed on formalin-fixed placental tissues of third-trimester pregnancies complicated by IUGR (n = 19) and pregnancies with appropriately grown fetuses (n = 27). In addition, histopathological examination of the placentas was performed, and histological findings were categorized into three groups: utero-placental vascular pathologies (UPVP), coagulation-related pathologies, and chronic inflammation. Statistical analysis revealed that villous trophoblastic IGF-IR immunostaining was significantly weaker in placentas with IUGR (p < 0.001), whereas trophoblastic Ki-67 proliferative index and VEGF immunoscoring did not show any significant difference. Histologically, UPVP and chronic inflammation were significant findings in placentas with IUGR (p = 0.04 and p = 0.04, respectively). In addition, placentas were significantly smaller in the IUGR group (p < 0.001). We conclude that villous trophoblastic IGF-IR expression may play a significant role in the pathogenesis of IUGR, and histopathological examination of placentas in pregnancies complicated by IUGR may yield significant findings. In contrast, based on our findings, trophoblastic proliferation and VEGF expression are unlikely to be significant parameters in the pathogenesis of IUGR.