Spatial multiomics map of trophoblast development in early pregnancy.

The relationship between the human placenta-the extraembryonic organ made by the fetus, and the decidua-the mucosal layer of the uterus, is essential to nurture and protect the fetus during pregnancy. Extravillous trophoblast cells (EVTs) derived from placental villi infiltrate the decidua, transforming the maternal arteries into high-conductance vessels1. Defects in trophoblast invasion and arterial transformation established during early pregnancy underlie common pregnancy disorders such as pre-eclampsia2. Here we have generated a spatially resolved multiomics single-cell atlas of the entire human maternal-fetal interface including the myometrium, which enables us to resolve the full trajectory of trophoblast differentiation. We have used this cellular map to infer the possible transcription factors mediating EVT invasion and show that they are preserved in in vitro models of EVT differentiation from primary trophoblast organoids3,4 and trophoblast stem cells5. We define the transcriptomes of the final cell states of trophoblast invasion: placental bed giant cells (fused multinucleated EVTs) and endovascular EVTs (which form plugs inside the maternal arteries). We predict the cell-cell communication events contributing to trophoblast invasion and placental bed giant cell formation, and model the dual role of interstitial EVTs and endovascular EVTs in mediating arterial transformation during early pregnancy. Together, our data provide a comprehensive analysis of postimplantation trophoblast differentiation that can be used to inform the design of experimental models of the human placenta in early pregnancy.

Human placental lactogen (human chorionic somatomammotropin) and oxytocin during pregnancy: Individual patterns and associations with maternal-fetal attachment, anxiety, and depression.

Previous studies support links among maternal-fetal attachment, psychological symptoms, and hormones during pregnancy and the post-partum period. Other studies connect maternal feelings and behaviors to oxytocin and suggest that an increase in oxytocin during pregnancy may prime maternal-fetal attachment. To date, researchers have not examined a possible association between maternal-fetal attachment with human placental lactogen although animal models are suggestive. In the current study, we sought to describe oxytocin and human placental lactogen levels as related to psychological constructs across pregnancy. Seventy women participated in the study. At each of three time-points (early, mid, and late pregnancy), the women had their blood drawn to assess oxytocin and human placental lactogen levels, and they completed psychological assessments measuring maternal-fetal attachment, anxiety, and depression. Our results indicate that oxytocin levels were statistically similar across pregnancy, but that human placental lactogen significantly increased across pregnancy. Results did not indicate significant associations of within-person (comparing individuals to themselves) oxytocin or human placental lactogen levels with maternal-fetal attachment. Additionally, results did not show between-person (comparing individuals to other individuals) oxytocin or human placental lactogen levels with maternal-fetal attachment. Oxytocin levels were not associated with anxiety; rather the stage of pregnancy moderated the effect of the within-person OT level on depression. Notably, increasing levels of human placental lactogen were significantly associated with increasing levels of both anxiety and depression in between subject analyses. The current study is important because it describes typical hormonal and maternal fetal attachment levels during each stage of pregnancy, and because it suggests an association between human placental lactogen and psychological symptoms during pregnancy. Future research should further elucidate these relationships.

The maternal-to-zygotic transition revisited.

The development of animal embryos is initially directed by maternal gene products. Then, during the maternal-to-zygotic transition (MZT), developmental control is handed to the zygotic genome. Extensive research in both vertebrate and invertebrate model organisms has revealed that the MZT can be subdivided into two phases, during which very different modes of gene regulation are implemented: initially, regulation is exclusively post-transcriptional and post-translational, following which gradual activation of the zygotic genome leads to predominance of transcriptional regulation. These changes in the gene expression program of embryos are precisely controlled and highly interconnected. Here, we review current understanding of the mechanisms that underlie handover of developmental control during the MZT.

Bovine peripheral blood MSCs chemotax towards inflammation and embryo implantation stimuli.

Mesenchymal stem cells (MSCs) have a great potential in regenerative medicine because of their multipotential and immunoregulatory capacities, while in early pregnancy they could participate in the immunotolerance of the mother towards the embryo. Peripheral blood constitutes an accessible source of MSCs. We successfully isolated peripheral blood MSC (pbMSCs) lines, with or without previous bone marrow mobilization. All pbMSCs lines obtained in both conditions presented classical MSC markers and properties, alkaline phosphatase activity and multipotent capacity to differentiate among adipogenic, osteogenic or chondrogenic lineages, and suppressed the proliferation of T cells. pbMSCs showed migratory capacity without cytokine stimulation while increasing their migration rate in the presence of inflammatory or embryo implantation stimuli. Interestingly, in contrast to MSCs derived from endometrial tissue, three pbMSCs lines also showed increased migration towards the IFN-τ implantation cytokine. Moreover, the secretome produced by an early implantation stage embryonic trophectoderm cell line showed a chemoattractant effect in pbMSCs. Our results suggest that circulating MSCs are present in the peripheral blood under healthy conditions. The fact that both the inflammation and implantation signals induced pbMSCs chemotaxis highlights MSC heterogeneity and suggests that their migratory capacity may differ according to their tissue of origin and would suggest the possible active recruitment of MSCs from bone marrow during pregnancy to repress the immune response to prevent the embryo rejection by the maternal organism.

Embryo-Maternal Interactions Underlying Reproduction in Mammals.

This Special Issue, "Embryo-Maternal Interactions Underlying Reproduction in Mammals", gathers a collection of 23 articles, 16 original research articles and 7 up-to-date reviews, providing new findings or summarizing current knowledge on embryo-maternal interactions in seven different mammalian species including humans. Considering the different players involved in these embryo-maternal interactions, articles are mainly focused on one of these different players: the oviduct, the uterus, the embryo or the emergent extracellular vesicles. Additionally, a few articles bring up the impact of reproductive, but also non-reproductive, diseases, as well as stress factors, on the establishment of pregnancy. We hope the readers enjoy this collection of articles and that the knowledge assembled here will support and inspire current and future research investigations. We would like to thank all authors for their contributions to this Special Issue.

Genetics of human female infertility†.

About 10% of women of reproductive age are unable to conceive or carry a pregnancy to term. Female factors alone account for at least 35% of all infertility cases and comprise a wide range of causes affecting ovarian development, maturation of oocytes, and fertilization competence, as well as the potential of a fertilized egg for preimplantation development, implantation, and fetal growth. Genetic abnormalities leading to infertility in females comprise large chromosome abnormalities, submicroscopic chromosome deletion and duplications, and DNA sequence variations in the genes that control numerous biological processes implicated in oogenesis, maintenance of ovarian reserve, hormonal signaling, and anatomical and functional development of female reproductive organs. Despite the great number of genes implicated in reproductive physiology by the study of animal models, only a subset of these genes is associated with human infertility. In this review, we mainly focus on genetic alterations identified in humans and summarize recent knowledge on the molecular pathways of oocyte development and maturation, the crucial role of maternal-effect factors during embryogenesis, and genetic conditions associated with ovarian dysgenesis, primary ovarian insufficiency, early embryonic lethality, and infertility.

How does toxoplasmosis affect the maternal-foetal immune interface and pregnancy?

Toxoplasma gondii is a zoonotic parasite which, depending on the geographical location, can infect between 10% and 90% of humans. Infection during pregnancy may result in congenital toxoplasmosis. The effects on the foetus vary depending on the stage of gestation in which primary maternal infection arises. A large body of research has focused on understanding immune response to toxoplasmosis, although few studies have addressed how it is affected by pregnancy or the pathological consequences of infection at the maternal-foetal interface. There is a lack of knowledge about how maternal immune cells, specifically macrophages, are modulated during infection and the resulting consequences for parasite control and pathology. Herein, we discuss the potential of T. gondii infection to affect the maternal-foetal interface and the potential of pregnancy to disrupt maternal immunity to T. gondii infection.

Alarmins at the maternal-fetal interface: involvement of inflammation in placental dysfunction and pregnancy complications 1.

Inflammation is known to be associated with placental dysfunction and pregnancy complications. Infections are well known to be a cause of inflammation but they are frequently undetectable in pregnancy complications. More recently, the focus has been extended to inflammation of noninfectious origin, namely caused by endogenous mediators known as "damage-associated molecular patterns (DAMPs)" or alarmins. In this manuscript, we review the mechanism by which inflammation, sterile or infectious, can alter the placenta and its function. We discuss some classical DAMPs, such as uric acid, high mobility group box 1 (HMGB1), cell-free fetal deoxyribonucleic acid (DNA) (cffDNA), S100 proteins, heat shock protein 70 (HSP70), and adenosine triphosphate (ATP) and their impact on the placenta. We focus on the main placental cells (i.e., trophoblast and Hofbauer cells) and describe the placental response to, and release of, DAMPs. We also covered the current state of knowledge about the role of DAMPs in pregnancy complications including preeclampsia, fetal growth restriction, preterm birth, and stillbirth and possible therapeutic strategies to preserve placental function.

Central role for melanocortin-4 receptors in offspring hypertension arising from maternal obesity.

Melanocortin-4 receptor (Mc4r)-expressing neurons in the autonomic nervous system, particularly in the paraventricular nucleus of the hypothalamus (PVH), play an essential role in blood pressure (BP) control. Mc4r-deficient (Mc4rKO) mice are severely obese but lack obesity-related hypertension; they also show a reduced pressor response to salt loading. We have previously reported that lean juvenile offspring born to diet-induced obese rats (OffOb) exhibit sympathetic-mediated hypertension, and we proposed a role for postnatally raised leptin in its etiology. Here, we test the hypothesis that neonatal hyperleptinemia due to maternal obesity induces persistent changes in the central melanocortin system, thereby contributing to offspring hypertension. Working on the OffOb paradigm in both sexes and using transgenic technology to restore Mc4r in the PVH of Mc4rKO (Mc4rPVH) mice, we have now shown that these mice develop higher BP than Mc4rKO or WT mice. We have also found that experimental hyperleptinemia induced in the neonatal period in Mc4rPVH and WT mice, but not in the Mc4rKO mice, leads to heightened BP and severe renal dysfunction. Thus, Mc4r in the PVH appears to be required for early-life programming of hypertension arising from either maternal obesity or neonatal hyperleptinemia. Early-life exposure of the PVH to maternal obesity through postnatal elevation of leptin may have long-term consequences for cardiovascular health.

Cysteine-X-cysteine motif chemokine ligand 12 and its receptor CXCR4: expression, regulation, and possible function at the maternal-conceptus interface during early pregnancy in pigs.

Cysteine-X-cysteine (CXC) motif chemokine ligand 12 (CXCL12) and its receptor, CXC chemokine receptor type 4 (CXCR4), are involved in regulating the proliferation, migration, and survival of trophoblast cells and the maternal immune response in humans and mice. The present study examined the expression, regulation, and function of CXCL12 and CXCR4 at the maternal-conceptus interface during pregnancy in pigs. The endometrium expressed CXCL12 and CXCR4 mRNAs with the greatest CXCL12 abundance on Day 15 of pregnancy. CXCL12 protein was localized mainly in endometrial epithelial cells, while CXCR4 protein was localized in subepithelial stromal cells, vascular endothelial cells, and immune cells in blood vessels in the endometrium during the estrous cycle and pregnancy. CXCL12 protein was detected in uterine flushing on Day 15 of pregnancy. The conceptus during early pregnancy and chorioallantoic tissues during mid-to-late pregnancy expressed CXCL12 and CXCR4. Interferon-γ increased the abundance of CXCL12, but not CXCR4 mRNA in endometrial explants. Recombinant CXCL12 (rCXCL12) protein dose-dependently increased migration of cultured porcine trophectoderm cells and peripheral blood mononuclear cells (PBMCs). Furthermore, rCXCL12 caused migration of T cells, but not natural killer cells, in PBMCs. This study revealed that interferon-γ-induced CXCL12 and its receptor, CXCR4, were expressed at the maternal-conceptus interface and increased the migration of trophectoderm cells and T cells at the time of implantation in pigs. These results suggest that CXCL12 may be critical for the establishment of pregnancy by regulating trophoblast migration and T cell recruitment into the endometrium during the implantation period in pigs.

Human Endometrial Exosomes Contain Hormone-Specific Cargo Modulating Trophoblast Adhesive Capacity: Insights into Endometrial-Embryo Interactions.

Embryo implantation into receptive endometrium requires synergistic endometrial-blastocyst interactions within the uterine cavity and is essential for establishing pregnancy. We demonstrate that exosomes (40-150 nm nanovesicles) released from endometrial epithelial cells are an important component of these interactions. We defined the proteome of purified endometrial epithelial-derived exosomes (Exos) influenced by menstrual cycle hormones estrogen (E; proliferative phase) and estrogen plus progesterone (EP; receptive phase) and examined their potential to modify trophoblast function. E-/EP-Exos were uniquely enriched with 254 and 126 proteins, respectively, with 35% newly identified proteins not previously reported in exosome databases. Importantly, EP-Exos protein cargo was related to fundamental changes in implantation: adhesion, migration, invasion, and extracellular matrix remodeling. These findings from hormonally treated ECC1 endometrial cancer cells were validated in human primary uterine epithelial cell-derived exosomes. Functionally, exosomes were internalized by human trophoblast cells and enhanced their adhesive capacity, a response mediated partially through active focal adhesion kinase (FAK) signaling. Thus, exosomes contribute to the endometrial-embryo interactions within the human uterine microenvironment essential for successful implantation.

Neuroanatomical and neurochemical basis of parenting: Dynamic coordination of motivational, affective and cognitive processes.

This article is part of a Special Issue "Parental Care". Becoming a parent is arguably the most profound transforming experience in life. It is also inherently very emotionally and physically demanding, such that the reciprocal interaction with the young changes the brain and behavior of the parents. In this review, we examine the neurobiological mechanisms of parenting primarily discussing recent research findings in rodents and primates, especially humans. We argue that it is essential to consider parenting within a conceptual framework that recognizes the dynamics of the reciprocal mother-young relationship, including both the complexity and neuroplasticity of its underlying mechanisms. Converging research suggests that the concerted activity of a distributed network of subcortical and cortical brain structures regulates different key aspects of parenting, including the sensory analysis of infant stimuli as well as motivational, affective and cognitive processes. The interplay among these processes depends on the action of various neurotransmitters and hormones that modulate the timely and coordinated execution of caregiving responses of the maternal circuitry exquisitely attuned to the young's affect, needs and developmental stage. We conclude with a summary and a set of questions that may guide future research.

Maternal medical conditions during pregnancy and gross motor development up to age 24 months in the Upstate KIDS study.

AIM: We examined whether children of mothers with a medical condition diagnosed before or during pregnancy took longer to achieve gross motor milestones up to age 24 months. METHOD: We obtained information on medical conditions using self-reports, birth certificates, and hospital records in 4909 mothers participating in Upstate KIDS, a population-based birth cohort. Mothers reported on their children's motor milestone achievement at 4, 8, 12, 18, and 24 months of age. RESULTS: After adjustment for covariates (including pre-pregnancy body mass index), children of mothers with gestational diabetes took longer to achieve sitting without support (hazard ratio [HR]=0.84, 95% confidence interval [CI] 0.75-0.93), walking with assistance (HR=0.88, 95% CI 0.77-0.98), and walking alone (HR=0.88, 95% CI 0.77-0.99) than children of females with no gestational diabetes. Similar findings emerged for maternal diabetes. Gestational hypertension was associated with a longer time to achieve walking with assistance. These associations did not change after adjustment for gestational age or birthweight. Severe hypertensive disorders of pregnancy were related to a longer time to achieve milestones, but not after adjustment for perinatal factors. INTERPRETATION: Children exposed to maternal diabetes, gestational or pre-gestational, may take longer to achieve motor milestones than non-exposed children, independent of maternal obesity.

Calming cycle theory: the role of visceral/autonomic learning in early mother and infant/child behaviour and development.

Results from a randomised controlled trial of Family Nurture Intervention (FNI) showed significantly improved maternal behaviours and infant neurodevelopment and behaviour through 18 months, including a significantly reduced risk for autism. Preliminary results from a pilot study of FNI in preschool children found significant reduction in adverse behaviour. CONCLUSION: Calming cycle theory proposes that early emotional behaviour is shaped by subcortical visceral/autonomic co-conditioning between mother and infant. Two new constructs, emotional connection and visceral/autonomic co-regulation, are defined within a functional Pavlovian conditioning framework and are theorised to be part of an evolutionarily conserved mammalian phenomenon first identified by Pavlov.

Determining the consequences of maternal obesity for offspring health.

NEW FINDINGS: What is the topic of this review? Observational studies have highlighted the association of increasing maternal body mass index with offspring adiposity and the subsequent risk of cardiometabolic disorders in adulthood. The in utero environment has become a target for intervention in order to reduce the burden of obesity, despite the mechanistic pathways of this association remaining unclear. What advances does it highlight? This short review provides a critical appraisal of the recent literature, including biological pathways and strategies to address causal relationships. The global obesity epidemic has been causally linked to changes in diet and lifestyle. Observational data and animal studies have now highlighted associations between in utero environmental exposures and increased susceptibility to obesity and related cardiometabolic disorders in later life. Maternal body mass index has been reported to show an independent association with offspring adiposity from an early age and to play an important role in the predisposition to obesity and metabolic disease in later life. Thus, the in utero environment has been the focus of recent targeted interventions to improve public health. In this review, we summarize recent progress in this field, including the use of animal models to investigate mechanistic links between maternal obesity and offspring metabolic risk. We then assess the level of evidence and challenges in establishing causal inferences from present birth cohorts.

Facilitation of action planning in children with autism: the contribution of the maternal body odor.

Imitation is a key socio-cognitive skill impaired in individuals with Autism Spectrum Conditions (ASC). It is known that the familiarity with an actor facilitates the appearance of imitative abilities. Here, we explore whether a highly familiar and socially relevant stimulus presented in the olfactory modality is able to improve spontaneous imitation as early as at the level of action planning. A group of 20 children with ASC and 20 controls observed their own mother or the mother of another child performing a reach-to-grasp action towards an object, under the exposure to their maternal odor, the odor of the mother of another child or no odor. Subsequently, children acted upon the same object with no specific instruction to imitate. Child's movement initiation time (MIT) served as an indicator of motor planning facilitation induced by action observation. Results suggest that for children with ASC (but not controls) MIT was significantly lower when exposed to the maternal odor both when interacting with a familiar or an unfamiliar model. In the former case, the performance is comparable to controls. The familiar model in the absence of any olfactory cue is able to induce a facilitation effect, but the maximal facilitation on MIT is evident when maternal odor and familiar model are paired. We hypothesize that for children with ASC the maternal odor provides relevant social motivation for taking advantage of others' actions when planning movements in an imitative context.

Fetal response to maternal hunger and satiation - novel finding from a qualitative descriptive study of maternal perception of fetal movements.

BACKGROUND: Maternal perception of decreased fetal movements is a specific indicator of fetal compromise, notably in the context of poor fetal growth. There is currently no agreed numerical definition of decreased fetal movements, with the subjective perception of a decrease on the part of the mother being the most significant definition clinically. Both qualitative and quantitative aspects of fetal activity may be important in identifying the compromised fetus.Yet, how pregnant women perceive and describe fetal activity is under-investigated by qualitative means. The aim of this study was to explore normal fetal activity, through first-hand descriptive accounts by pregnant women. METHODS: Using qualitative descriptive methodology, interviews were conducted with 19 low-risk women experiencing their first pregnancy, at two timepoints in their third trimester. Interview transcripts were later analysed using qualitative content analysis and patterns of fetal activity identified were then considered along-side the characteristics of the women and their birth outcomes. RESULTS: This paper focuses on a novel finding; the description by pregnant women of fetal behaviour indicative of hunger and satiation. Full findings will be presented in later papers. Most participants (74% 14 of 19) indicated mealtimes were a time of increased fetal activity. Eight participants provided detailed descriptions of increased activity around meals, with seven (37% 7 of 19) of these specifying increased fetal activity prior to meals or in the context of their own hunger. These movements were interpreted as a fetal demand for food often prompting the mother to eat. Interestingly, the women who described increased fetal activity in the context of hunger subsequently gave birth to smaller infants (mean difference 364 gm) than those who did not describe a fetal response to hunger. CONCLUSIONS: Food seeking behaviour may have a pre-birth origin. Maternal-fetal interaction around mealtimes could constitute an endocrine mediated communication, in the interests of maintaining optimal intrauterine conditions. Further research is warranted to explore this phenomenon and the potential influence of feeding on the temporal organisation of fetal activity in relation to growth.

Dysregulation of CREB5 Impairs Decidualization and Maternal-Fetal Interactions by Inhibiting Autophagy in Recurrent Spontaneous Abortion.

BACKGROUND: Clinically, recurrent spontaneous abortion (RSA) is a pregnancy illness that is difficult to treat. Impaired decidualization is a documented cause of RSA, but the etiology and mechanism are still unknown. cAMP-responsive element binding protein 5 (CREB5) is a member of the ATF/CREB family. CREB5 has been reported to be related to pathological pregnancy, but there are few related studies on this topic in patients with RSA, and the underlying mechanism is unclear. METHODS: We collected decidual tissues from RSA patients and healthy pregnant women to measure the expression level of CREB5, PRL, IGFBP1, ATG5, LC3B, and SQSTM/p62. Then, the changes in CREB5 expression and autophagy levels were measured in human endometrial stromal cells (hESCs) during decidualization. The expression levels of PRL and IGFBP1 were tested in sh-CREB5/ov-CREB5 hESCs after decidualization induction, and the autophagy level in sh-CREB5/ov-CREB5 hESCs was measured without decidualization induction. The decidualization ability of sh-CREB5 and ov-CREB5 hESCs treated with an autophagy inducer or inhibitor was measured. To investigate the effect of CREB5 in hESCs on the invasion and migration of HTR8/SVneo cells, we performed a coculture experiment. Finally, we examined the expression of CREB5 and autophagy key proteins in mouse decidual tissues by constructing an abortion mouse model. RESULTS: In our study, we found that the expression of CREB5 was unusually elevated in the uterine decidua of RSA patients, but the expression of PRL, IGFBP1, and autophagy were decreased. During the decidualization of hESCs, the expression of CREB5 gradually decreases in a time-dependent manner with increasing autophagy. Moreover, by knocking down or overexpressing CREB5 in hESCs, it was found that CREB5 can impair decidualization and reduce autophagy in hESCs. Furthermore, the damage caused by CREB5 in terms of decidualization can be reversed by the addition of an autophagy inducer (rapamycin). In addition, CREB5 can increase the secretion of proteins (IL-1ß and TGF-ß1) in hESCs to inhibit trophoblast invasion and migration. CONCLUSIONS: Our data support the supposition that CREB5 disturbs the decidualization of endometrial stromal cells and interactions at the maternal-fetal interface by inhibiting autophagy and that its abnormal upregulation and dysfunction may lead to RSA. It may function as a diagnostic and therapeutic target for RSA. Similarly, we found that in the spontaneous abortion mouse model, the expression of CREB5 in the decidual tissue of the abortion group was significantly increased, and autophagy was decreased.

Profiling Lgals9 splice variant expression at the fetal-maternal interface: implications in normal and pathological human pregnancy.

Disruption of fetal-maternal tolerance mechanisms can contribute to pregnancy complications, including spontaneous abortion. Galectin-9 (LGALS9), a tandem repeat lectin associated with immune modulation, is expressed in the endometrium during the mid and late secretory phases and in decidua during human early pregnancy. However, the role of LGALS9 during pregnancy remains poorly understood. We used real-time PCR and immunohistochemical staining to analyze the expression of Lgals9/LGALS9 during mouse gestation as well as in human tissues obtained from normal pregnancy and spontaneous abortions. In mice, three Lgals9 splice variants were detected, the expression of which was differentially regulated during gestation. Furthermore, decidual Lgals9 expression was deregulated in a mouse model of spontaneous abortion, whereas placental levels did not change. We further found that the LGALS9 D5 isoform suppresses interferon gamma production by decidual natural killer cells. In human patients, six Lgals9 splice variants were detected, and a decrease in Lgals9 D5/10 was associated with spontaneous abortion. Altogether, these results show a differential regulation of Lgals9 isoform expression during normal and pathological pregnancies and designate Lgals9 as a potential marker for adverse pregnancy outcomes.