Expression of eight glucocorticoid receptor isoforms in the human preterm placenta vary with fetal sex and birthweight

Sex-dimorphic pathways in the associations between maternal trait anxiety, infant BDNF methylation, and negative emotionality

Maternal antenatal anxiety is an emerging risk factor for child emotional development. Both sex and epigenetic mechanisms, such as DNA methylation, may contribute to the embedding of maternal distress into emotional outcomes. Here, we investigated sex-dependent patterns in the association between antenatal maternal trait anxiety, methylation of the brain-derived neurotrophic factor gene (BDNF DNAm), and infant negative emotionality (NE). Mother-infant dyads (N = 276) were recruited at delivery. Maternal trait anxiety, as a marker of antenatal chronic stress exposure, was assessed soon after delivery using the Stait-Trait Anxiety Inventory (STAI-Y). Infants' BDNF DNAm at birth was assessed in 11 CpG sites in buccal cells whereas infants' NE was assessed at 3 (N = 225) and 6 months (N = 189) using the Infant Behavior Questionnaire-Revised (IBQ-R). Hierarchical linear analyses showed that higher maternal antenatal anxiety was associated with greater 6-month-olds' NE. Furthermore, maternal antenatal anxiety predicted greater infants' BDNF DNAm in five CpG sites in males but not in females. Higher methylation at these sites was associated with greater 3-to-6-month NE increase, independently of infants' sex. Maternal antenatal anxiety emerged as a risk factor for infant's NE. BDNF DNAm might mediate this effect in males. These results may inform the development of strategies to promote mothers and infants' emotional well-being.

How is prenatal stress transmitted from the mother to the fetus?

Prenatal stress programmes long-lasting neuroendocrine and behavioural changes in the offspring. Often this programming is maladaptive and sex specific. For example, using a rat model of maternal social stress in late pregnancy, we have demonstrated that adult prenatally stressed male, but not prenatally stressed female offspring display heightened anxiety-like behaviour, whereas both sexes show hyperactive hypothalamo-pituitary-adrenal (HPA) axis responses to stress. Here, we review the current knowledge of the mechanisms underpinning dysregulated HPA axis responses, including evidence supporting a role for reduced neurosteroid-mediated GABAergic inhibitory signalling in the brains of prenatally stressed offspring. How maternal psychosocial stress is signalled from the mother to the fetuses is unclear. Direct transfer of maternal glucocorticoids to the fetuses is often considered to mediate the programming effects of maternal stress on the offspring. However, protective mechanisms including attenuated maternal stress responses and placental 11β-hydroxysteroid dehydrogenase-2 (which inactivates glucocorticoids) should limit materno-fetal glucocorticoid transfer during pregnancy. Moreover, a lack of correlation between maternal stress, circulating maternal glucocorticoid levels and circulating fetal glucocorticoid levels is reported in several studies and across different species. Therefore, here we interrogate the evidence for a role for maternal glucocorticoids in mediating the effects of maternal stress on the offspring and consider the evidence for alternative mechanisms, including an indirect role for glucocorticoids and the contribution of changes in the placenta in signalling the stress status of the mother to the fetus.

Independent and Combined Effects of Prenatal Alcohol Exposure and Prenatal Stress on Fetal HPA Axis Development

Prenatal alcohol exposure (PAE) and prenatal stress (PS) are highly prevalent conditions known to affect fetal programming of the hypothalamic-pituitary-adrenal (HPA) axis. The objectives of this study were to assess the effect of light PAE, PS, and PAE-PS interaction on fetal HPA axis activity assessed via placental and umbilical cord blood biomarkers. Participants of the ENRICH-2 cohort were recruited during the second trimester and classified into the PAE and unexposed control groups. PS was assessed by the Perceived Stress Scale. Placental tissue was collected promptly after delivery; gene and protein analysis for 11β-HSD1, 11β-HSD2, and pCRH were conducted by qPCR and ELISA, respectively. Umbilical cord blood was analyzed for cortisone and cortisol. Pearson correlation and multivariable linear regression examined the association of PAE and PS with HPA axis biomarkers. Mean alcohol consumption in the PAE group was ~2 drinks/week. Higher PS was observed in the PAE group (p < 0.01). In multivariable modeling, PS was associated with pCRH gene expression (β = 0.006, p < 0.01), while PAE was associated with 11β-HSD2 protein expression (β = 0.56, p < 0.01). A significant alcohol-by-stress interaction was observed with respect to 11β-HSD2 protein expression (p < 0.01). Results indicate that PAE and PS may independently and in combination affect fetal programming of the HPA axis.

Sex differences in growth and mortality in pregnancy-associated hypertension

BACKGROUND

It is hypothesized that male fetuses prioritize growth, resulting in increased mortality, whereas females reduce growth in the presence of adversity. Preeclampsia reflects a chronic condition, in which fetuses have the opportunity to adjust growth. If females reduce their growth in response to preeclampsia, but males attempt to maintain growth at the cost of survival, we predict that differences in birthweight between preeclamptic and non-preeclamptic pregnancies will be greater among females, whereas differences in mortality will be greater among males.

METHODS

We analysed data from the Centers for Disease Control and Prevention. We compared pregnancies with pregnancy-associated hypertension (PAH) and controls.

RESULTS

The difference in birthweight between pregnancies affected by PAH and controls varied by fetal sex and gestational age. Among pregnancies of White individuals, at 34-35 weeks, the difference between PAH and controls was higher among females, as predicted. However, this pattern was reversed earlier in pregnancy and around term. Such variation was not significant in Black pregnancies. In both Black and White pregnancies, early in gestation, males had lower odds of death in PAH pregnancies, but higher odds of death in control pregnancies, counter to our prediction. Later, males had higher odds of death in PAH and controls, although the increased odds of death in males was not higher in PAH pregnancies than in controls. Overall, the difference in birthweight between surviving and non-surviving infants was greater in males than in females, opposite to our prediction.

CONCLUSIONS

The impact of PAH on birthweight and survival varies widely throughout gestation. Differences in birthweight and survival between male and female PAH and controls are generally not consistent with the hypothesis that males prioritize fetal growth more than females, and that this is a cause of increased mortality in males.

Glucocorticoids and Their Receptor Isoforms: Roles in Female Reproduction, Pregnancy, and Foetal Development

Alterations in the hypothalamic-pituitary-adrenal (HPA) axis and associated changes in circulating levels of glucocorticoids are integral to an organism's response to stressful stimuli. Glucocorticoids acting via glucocorticoid receptors (GRs) play a role in fertility, reproduction, placental function, and foetal development. GRs are ubiquitously expressed throughout the female reproductive system and regulate normal reproductive function. Stress-induced glucocorticoids have been shown to inhibit reproduction and affect female gonadal function by suppressing the hypothalamic-pituitary-gonadal (HPG) axis at each level. Furthermore, during pregnancy, a mother's exposure to prenatal stress or external glucocorticoids can result in long-lasting alterations to the foetal HPA and neuroendocrine function. Several GR isoforms generated via alternative splicing or translation initiation from the GR gene have been identified in the mammalian ovary and uterus. The GR isoforms identified include the splice variants, GRα and GRβ, and GRγ and GR-P. Glucocorticoids can exert both stimulatory and inhibitory effects and both pro- and anti-inflammatory functions in the ovary, in vitro. In the placenta, thirteen GR isoforms have been identified in humans, guinea pigs, sheep, rats, and mice, indicating they are conserved across species and may be important in mediating a differential response to stress. Distinctive responses to glucocorticoids, differential birth outcomes in pregnancy complications, and sex-based variations in the response to stress could all potentially be dependent on a particular GR expression pattern. This comprehensive review provides an overview of the structure and function of the GR in relation to female fertility and reproduction and discusses the changes in the GR and glucocorticoid signalling during pregnancy. To generate this overview, an extensive non-systematic literature search was conducted across multiple databases, including PubMed, Web of Science, and Google Scholar, with a focus on original research articles, meta-analyses, and previous review papers addressing the subject. This review integrates the current understanding of GR variants and their roles in glucocorticoid signalling, reproduction, placental function, and foetal growth.

Neuronal and Astroglial Localization of Glucocorticoid Receptor GRα in Adult Zebrafish Brain (Danio rerio)

Glucocorticoid receptor α (GRα), a ligand-regulated transcription factor, mainly activated by cortisol in humans and fish, mediates neural allostatic and homeostatic functions induced by different types of acute and chronic stress, and systemic inflammation. Zebrafish GRα is suggested to have multiple transcriptional effects essential for normal development and survival, similarly to mammals. While sequence alignments of human, monkey, rat, and mouse GRs have shown many GRα isoforms, we questioned the protein expression profile of GRα in the adult zebrafish (Danio rerio) brain using an alternative model for stress-related neuropsychiatric research, by means of Western blot, immunohistochemistry and double immunofluorescence. Our results identified four main GRα-like immunoreactive bands (95 kDa, 60 kDa, 45 kDa and 35 kDa), with the 95 kDa protein showing highest expression in forebrain compared to midbrain and hindbrain. GRα showed a wide distribution throughout the antero-posterior zebrafish brain axis, with the most prominent labeling within the telencephalon, preoptic, hypothalamus, midbrain, brain stem, central grey, locus coeruleus and cerebellum. Double immunofluorescence revealed that GRα is coexpressed in TH+, β₂-AR+ and vGLUT+ neurons, suggesting the potential of GRα influences on adrenergic and glutamatergic transmission. Moreover, GRα was co-localized in midline astroglial cells (GFAP+) within the telencephalon, hypothalamus and hindbrain. Interestingly, GRα expression was evident in the brain regions involved in adaptive stress responses, social behavior, and sensory and motor integration, supporting the evolutionarily conserved features of glucocorticoid receptors in the zebrafish brain.

Research progress on the impact of anxiety and depression on embryo transfer outcomes of in vitro fertilization

Infertile women who receive in vitro fertilization-embryo transfer (IVF-ET) often present psychological distress such as anxiety, depression and perceived stress. This adverse psychological state can affect the immune homeostasis at the mother-fetus interface, the incubation of blastula and the receptivity of the maternal endometrium through the psycho-neuro-immuno-endocrine network, which in turns affect the proliferation, invasion and vascular remodeling of the embryo trophoblast, and reduces the success rate of embryo transfer. This adverse outcome of embryo transfer will further aggravate the psychological pain of patients, forming a vicious circle. The positive partner effect between husband and wife or the use of cognitive behavioral therapy, acupuncture, yoga and other measures for psychological intervention before and after IVF-ET, may break the vicious cycle and improve clinical pregnancy rate, continuous pregnancy rate and live birth rate after IVF-ET by alleviating anxiety and depression. This article reviews the research progress on anxiety and depression states in women receiving IVF-ET and the impact on outcome of IVF-ET and related mechanisms, as well as the application of psychological intervention for alleviating anxiety and depression, so as to provide insights in improving the outcome of IVF-ET.

Maternal Dexamethasone Exposure Induces Sex-Specific Changes in Histomorphology and Redox Homeostasis of Rat Placenta

As the mediator between the mother and fetus, the placenta allows the most appropriate environment and optimal fetal growth. The placenta of one sex sometimes has a greater ability over the other to respond to and protect against possible maternal insults. Here, we characterized sex differences in the placenta’s morphological features and antioxidant status following dexamethasone (Dx) exposure. Pregnant rats were exposed to Dx or saline. The placenta was histologically and stereologically analyzed. The activity of the antioxidant enzymes, lipid peroxides (TBARS), superoxide anion and nitric oxide (NO) was measured. The decrease in placental zone volumes was more pronounced (p < 0.05) in female placentas. The volume density of PCNA-immunopositive nuclei was reduced (p < 0.05) in both sexes. The reduced (p < 0.05) antioxidant enzyme activities, enhanced TBARS and NO concentration indicate that Dx exposure triggered oxidative stress in the placenta of both fetal sexes, albeit stronger in the placenta of female fetuses. In conclusion, maternal Dx treatment reduced the size and volume of placental zones, altered placental histomorphology, decreased cell proliferation and triggered oxidative stress; however, the placentas of female fetuses exerted more significant responses to the treatment effects. The reduced placental size most probably reduced the transport of nutrients and oxygen, thus resulting in the reduced weight of fetuses, similar in both sexes. The lesser ability of the male placenta to detect and react to maternal exposure to environmental challenges may lead to long-standing health effects.

Differential expression of placental 11β-HSD2 induced by high maternal glucocorticoid exposure mediates sex differences in placental and fetal development

A variety of adverse environmental factors during pregnancy cause maternal chronic stress. Caffeine is a common stressor, and its consumption during pregnancy is widespread. Our previous study showed that prenatal caffeine exposure (PCE) increased maternal blood glucocorticoid levels and caused abnormal development of offspring. However, the placental mechanism for fetal development inhibition caused by PCE-induced high maternal glucocorticoid has not been reported. This study investigated the effects of PCE-induced high maternal glucocorticoid level on placental and fetal development by regulating placental 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2) expression and its underlying mechanism. First, human placenta and umbilical cord blood samples were collected from women without prenatal use of synthetic glucocorticoids. We found that placental 11β-HSD2 expression was significantly correlated with umbilical cord blood cortisol level and birth weight in male newborns but not in females. Furthermore, we established a rat model of high maternal glucocorticoids induced by PCE (caffeine, 60 mg/kg·d, ig), and found that the expression of 11β-HSD2 in male PCE placenta was decreased and negatively correlated with the maternal/fetal/placental corticosterone levels. Meanwhile, we found abnormal placental structure and nutrient transporter expression. In vitro, BeWo cells were used and confirm that 11β-HSD2 mediated inhibition of placental nutrient transporter expression induced by high levels of glucocorticoid. Finally, combined with the animal and cell experiments, we further confirmed that high maternal glucocorticoid could activate the GR-C/EBPα-Egr1 signaling pathway, leading to decreased expression of 11β-HSD2 in males. However, there was no significant inhibition of placental 11β-HSD2 expression, placental and fetal development in females. In summary, we confirmed that high maternal glucocorticoids could regulate placental 11β-HSD2 expression in a sex-specific manner, leading to differences in placental and fetal development. This study provides the theoretical and experimental basis for analyzing the inhibition of fetoplacental development and its sex difference caused by maternal stress.

Identification of multiple isoforms of glucocorticoid receptor in nasal polyps of patients with chronic rhinosinusitis

Background

The conventional belief that glucocorticosteroid (GC) acts through a single brand glucocorticoid receptor (GR)α protein has changed dramatically with the discovery of multiple GR isoforms. We aimed to evaluate whether multiple GR protein isoforms are expressed in chronic rhinosinusitis with nasal polyps (CRSwNP) and whether GR protein isoform expression profiles differ between different endotypes of CRSwNP.

Methods

Thirty-eight patients with CRSwNP and ten healthy volunteers were included. The protein expression of multiple GR isoforms in nasal polyps (NPs) tissue and control mucosae was examined by western blot analysis with different GR antibodies.

Results

Five bands, including three bands for known proteins (GRα-A/B, GRα-C, and GRα-D) and two bands for unidentified proteins at 67 kilodaltons (kDa) and 60 kDa, were identified with both total GR antibody (PA1-511A) and GRα-specific antibody (PA1-516). GRα-D intensity, which was abundant in nasal mucosa, was significantly increased in the CRSwNP group and was especially elevated in the noneosinophilic CRSwNP (NE-CRSwNP) group (PA1-511A: P < 0.001 and P = 0.0018; PA1-516: P < 0.003 and P = 0.006, respectively). Additionally, the intensities of the newly recognized 67 kDa and 60 kDa bands were much greater in the NE-CRSwNP subgroup than in the eosinophilic CRSwNP (E-CRSwNP) subgroup; in the E-CRSwNP subgroup, the median intensities were even lower than those in the control group.

Conclusions

This study provides evidence that nasal tissues express multiple GR protein isoforms. GR protein isoforms presented disease and tissue-specific expression profiles that differed between the CRSwNP and control groups and between the E-CRSwNP and NE-CRSwNP subgroups.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40463-022-00561-1.

Prenatal stress and its association with amygdala-related structural covariance patterns in youth

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Prenatal exposure to stress predicts amygdala degree centrality in young adulthood.

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High (vs. low) stress group showed lower structural covariance degree of amygdala.

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These effects were particularly significant in men.

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Global network parameters did not drive these effects.

Background

Prenatal stress influences brain development and mood disorder vulnerability. Brain structural covariance network (SCN) properties based on inter-regional volumetric correlations may reflect developmentally-mediated shared plasticity among regions. Childhood trauma is associated with amygdala-centric SCN reorganization patterns, however, the impact of prenatal stress on SCN properties remains unknown.

Methods

The study included participants from the European Longitudinal Study of Pregnancy and Childhood (ELSPAC) with archival prenatal stress data and structural MRI acquired in young adulthood (age 23–24). SCNs were constructed based on Freesurfer-extracted volumes of 7 subcortical and 34 cortical regions. We compared amygdala degree centrality, a measure of hubness, between those exposed to high vs. low (median split) prenatal stress, defined by maternal reports of stressful life events during the first (n = 93, 57% female) and second (n = 125, 54% female) half of pregnancy. Group differences were tested across network density thresholds (5–40%) using 10,000 permutations, with sex and intracranial volume as covariates, followed by sex-specific analyses. Finally, we sought to replicate our results in an independent all-male sample (n = 450, age 18–20) from the Avon Longitudinal Study of Parents and Children (ALSPAC).

Results

The high-stress during the first half of pregnancy ELSPAC group showed lower amygdala degree particularly in men, who demonstrated this difference at 10 consecutive thresholds, with no significant differences in global network properties. At the lowest significant density threshold, amygdala volume was positively correlated with hippocampus, putamen, rostral anterior and posterior cingulate, transverse temporal, and pericalcarine cortex in the low-stress (p(FDR) < 0.027), but not the high-stress (p(FDR) > 0.882) group. Although amygdala degree was nominally lower across thresholds in the high-stress ALSPAC group, these results were not significant.

Conclusion

Unlike childhood trauma, prenatal stress may shift SCN towards a less amygdala-centric SCN pattern, particularly in men. These findings did not replicate in an all-male ALSPAC sample, possibly due to the sample’s younger age and lower prenatal stress exposure.

Protective Effects of Interleukin-1 Blockade on Group B Streptococcus-Induced Chorioamnionitis and Subsequent Neurobehavioral Impairments of the Offspring

Group B Streptococcus (GBS) is one of the most common bacteria isolated in human chorioamnionitis. Placental infection due to GBS is a major risk factor for fetal organ injuries, preterm birth, perinatal morbidity and mortality, and life-long multiorgan morbidities. Preclinical and clinical studies have shown that GBS-induced infection drives polymorphonuclear (PMN) cell infiltration within the placenta, the hallmark of human chorioamnionitis. In preclinical and clinical studies, the upregulation of interleukin(IL)-1β in the placenta and maternal/fetal blood was associated with a high risk of neurodevelopmental impairments in the progeny. We hypothesized that targeted IL-1 blockade administered to the dam alleviates GBS-induced chorioamnionitis and the downstream fetal inflammatory response syndrome (FIRS). IL-1 receptor antagonist (IL-1Ra) improved the gestational weight gain of GBS-infected dams and did not worsen the infectious manifestations. IL-1Ra reduced the IL-1β titer in the maternal sera of GBS-infected dams. IL-1Ra decreased the levels of IL-1β, IL-6, chemokine (C-X-C motif) ligand 1 (CXCL1), and polymorphonuclear (PMN) infiltration in GBS-infected placenta. IL-1Ra treatment reduced the IL-1β titer in the fetal sera of GBS-exposed fetuses. IL-1 blockade also alleviated GBS-induced FIRS and subsequent neurobehavioral impairments of the offspring without worsening the outcome of GBS infection. Altogether, these results showed that IL-1 plays a key role in the physiopathology of live GBS-induced chorioamnionitis and consequent neurobehavioral impairments.

Sexual dimorphism in placental development and its contribution to health and diseases

According to the Developmental Origin of Health and Disease (DOHaD), intrauterine exposure to adverse environments can affect fetus and birth outcomes and lead to long-term disease susceptibility. Evidence has shown that neonatal outcomes and the timing and severity of adult diseases are sexually dimorphic. As the link between mother and fetus, the placenta is an essential regulator of fetal development programming. It is found that the physiological development trajectory of the placenta has sexual dimorphism. Furthermore, under pathological conditions, the placental function undergoes sex-specific adaptation to ensure fetal survival. Therefore, the placenta may be an important mediator of sexual dimorphism in neonatal outcomes and adult disease susceptibility. Few systematic reviews have been conducted on sexual dimorphism in placental development and its underlying mechanisms. In this review, sex chromosomes and sex hormones, as the main reasons for sexual differentiation of the placenta, will be discussed. Besides, in the etiology of fetal-originated adult diseases, overexposure to glucocorticoids is closely related to adverse neonatal outcomes and long-term disease susceptibility. Studies have found that prenatal glucocorticoid overexposure leads to sexually dimorphic expression of placental glucocorticoid receptor isoforms, resulting in different sensitivity of the placenta to glucocorticoids, and may further affect fetal development. The present review examines what is currently known about sex differences in placental development and the underlying regulatory mechanisms of this sex bias. This review highlights the importance of placental contributions to the origins of sexual dimorphism in health and diseases. It may help develop personalized diagnosis and treatment strategies for fetal development in pathological pregnancies.

Let's Talk about Placental Sex, Baby: Understanding Mechanisms That Drive Female- and Male-Specific Fetal Growth and Developmental Outcomes

It is well understood that sex differences exist between females and males even before they are born. These sex-dependent differences may contribute to altered growth and developmental outcomes for the fetus. Based on our initial observations in the human placenta, we hypothesised that the male prioritises growth pathways in order to maximise growth through to adulthood, thereby ensuring the greatest chance of reproductive success. However, this male-specific “evolutionary advantage” likely contributes to males being less adaptable to shifts in the in-utero environment, which then places them at a greater risk for intrauterine morbidities or mortality. Comparatively, females are more adaptable to changes in the in-utero environment at the cost of growth, which may reduce their risk of poor perinatal outcomes. The mechanisms that drive these sex-specific adaptations to a change in the in-utero environment remain unclear, but an increasing body of evidence within the field of developmental biology would suggest that alterations to placental function, as well as the feto-placental hormonal milieu, is an important contributing factor. Herein, we have addressed the current knowledge regarding sex-specific intrauterine growth differences and have examined how certain pregnancy complications may alter these female- and male-specific adaptations.

A preferential switch between placental GR exon 1 promoter variants in the presence of maternal asthma or inflammation upregulates GRα D isoforms

INTRODUCTION

The human placenta expresses multiple glucocorticoid receptor (GR) isoforms that may be partially regulated by the untranslated 5' exon 1 GR gene promoter region which consists of 9 different promoters and 13 splice variants. The objective of this study was to determine which GR exon 1 variants are expressed in the human placenta and relate these findings to GR mRNA and protein expression.

METHODS

Placental extracts from pregnancies with or without the complication of maternal asthma and trophoblast cells exposed to an inflammatory challenge in vitro were examined using PCR and Western blot to measure GR exon 1 variants, GR splice variant mRNA and GR protein isoforms, respectively.

RESULTS

All 9 GR exon 1 variants were detectable in the human placenta and included GR exons 1A, 1B, 1C, 1D, 1E, 1F, 1H, 1I and 1J. In the presence of maternal asthma and a male fetus there was preferential expression of GR exon 1B, 1C, IF and 1J (KW-ANOVA, P < 0.05) which were positively correlated with GRα D3 protein isoform. In female placentae from pregnancies complicated by asthma there was no upregulation of any exon 1 variant (KW-ANOVA, P < 0.05). Exposure of BeWo trophoblast cell line to an inflammatory challenge, lipopolysaccharide, in vitro, resulted in preferential expression of GR exon 1B, 1D, 1E and 1H and associated with GRα-D1 protein upregulation.

DISCUSSION

The preferential expression of different GR exon 1 promoters drive the upregulation of GRα D isoforms and contribute to glucocorticoid resistance observed in male placentae of pregnancies complicated by asthma.

Dexamethasone-induced intrauterine growth restriction modulates expression of placental vascular growth factors and fetal and placental growth

Prenatal exposure to glucocorticoids (GC) is a central topic of interest in medicine since GCs are essential for the maturation of fetal organs and intrauterine growth. Synthetic glucocorticoids, which are used in obstetric practice, exert beneficial effects on the fetus, but have also been reported to lead to intrauterine growth retardation (IUGR). In this study, a model of growth restriction in mice was established through maternal administration of dexamethasone during late gestation. We hypothesised that GC overexposure may adversely affect placental angiogenesis and fetal and placental growth. Female BALB/c mice were randomly assigned to control or dexamethasone treatment, either left to give birth or euthanised on days 15, 16, 17 and 18 of gestation followed by collection of maternal and fetal tissue. The IUGR rate increased to 100% in the dexamethasone group (8 mg/kg body weight on gestational days 14 and 15) and pups had clinical features of symmetrical IUGR at birth. Dexamethasone administration significantly decreased maternal body weight gain and serum corticosterone levels. Moreover, prenatal dexamethasone treatment not only induced fetal growth retardation but also decreased placental weight. In IUGR placentas, VEGFA protein levels and mRNA expression of VEGF receptors were reduced and NOS activity was lower. Maternal dexamethasone administration also reduced placental expression of the GC receptor, αGR. We demonstrated that maternal dexamethasone administration causes fetal and placental growth restriction. Furthermore, we propose that the growth retardation induced by prenatal GC overexposure may be caused, at least partially, by an altered placental angiogenic profile.

Alterations to Placental Glucocorticoid Receptor Expression with Alcohol Consumption

Maternal alcohol consumption during pregnancy results in elevated vulnerability to intrauterine growth restriction, preterm birth, miscarriage, and stillbirth. Many of the detrimental effects of fetal alcohol exposure may be mediated through placental dysfunction; however, the exact mechanisms remain unknown. Here, we aimed to determine the effect of maternal alcohol exposure prior to and during early pregnancy on placental glucocorticoid receptor (GR) isoforms, associated GR regulated genes, and infant outcomes. Participants carrying singleton fetuses (n = 113) were recruited during early pregnancy. Amount and type of alcohol consumed over the last 12 months were obtained at 18 weeks of gestation. The level of drinking was separated into none (0 g/day), low (< 10 g/day), moderate (10-100 g/day), and heavy (> 100 g/day). At delivery, placental weight, infant sex, birthweight, and head circumference were recorded. Placental GR isoforms and genes involved in downstream signalling pathways were quantified. The majority of women (70.8%) consumed alcohol. Of these, most consumed low (48.8%) or moderate (37.5%) amounts. Placental weight was unaffected by alcohol consumption, but infants born to heavy drinkers tended to be lighter at birth. In female, but not male, placentae, maternal alcohol consumption resulted in increased GRαC and decreased GRαD1 cytoplasmic expression. In both female and male placentae, a dampened inflammatory response was evident with maternal alcohol consumption, involving downregulated IL6R and upregulated POU2F2 gene expression, respectively. Maternal alcohol consumption in the months prior to, and/or during early, pregnancy alters placental GR isoform and expression of some inflammatory genes in a sex-specific manner.

Limitations to intergenerational inheritance: subchronic paternal stress preconception does not influence offspring anxiety

Independent studies have observed that a paternal history of stress or trauma is associated with his children having a greater likelihood of developing psychopathologies such as anxiety disorders. This father-to-child effect is reproduced in several mouse models of stress, which have been crucial in developing a greater understanding of intergenerational epigenetic inheritance. We previously reported that treatment of C57Bl/6J male breeders with low-dose corticosterone (CORT) for 28 days prior to mating yielded increased anxiety-related behaviours in their male F1 offspring. The present study aimed to determine whether subchronic 7-day CORT treatment of male mice just prior to mating would be sufficient to induce intergenerational modifications of anxiety-related behaviours in offspring. We report that subchronic CORT treatment of male breeders reduced their week-on-week body weight gain and altered NR3C1 and CRH gene expression in the hypothalamus. There were no effects on sperm count and glucocorticoid receptor protein levels within the epididymal tissue of male breeders. Regarding the F1 offspring, screening for anxiety-related behaviours using the elevated-plus maze, light–dark box, and novelty-suppressed feeding test revealed no differences between the offspring of CORT-treated breeders compared to controls. Thus, it is crucial that future studies take into consideration the duration of exposure when assessing the intergenerational impacts of paternal health.

A role for microRNAs in the epigenetic control of sexually dimorphic gene expression in the human placenta

Aim: The contribution of miRNAs as epigenetic regulators of sexually dimorphic gene expression in the placenta is unknown. Materials & methods: 382 placentas from the extremely low gestational age newborns (ELGAN) cohort were evaluated for expression levels of 37,268 mRNAs and 2,102 miRNAs using genome-wide RNA-sequencing. Differential expression analysis was used to identify differences in the expression based on the sex of the fetus. Results: Sexually dimorphic expression was observed for 128 mRNAs and 59 miRNAs. A set of 25 miRNA master regulators was identified that likely contribute to the sexual dimorphic mRNA expression. Conclusion: These data highlight sex-dependent miRNA and mRNA patterning in the placenta and provide insight into a potential mechanism for observed sex differences in outcomes.

Genome-wide microRNA expression analysis in human placenta reveals sex-specific patterns: an ENVIRONAGE birth cohort study

There is an increasing interest in microRNAs (miRNAs) as they are of utmost importance in gene regulation at the posttranscriptional level. Sex-related susceptibility for non-communicable diseases later in life could originate in early life. Until now, no data on sex-specific miRNA expression are available for the placenta. Therefore, we investigated the difference by sex of newborn's miRNA expression in human placental tissue. Within the ENVIRONAGE birth cohort, miRNA and mRNA expression profiling was performed in 60 placentae (50% boys) using Agilent (8 × 60 K) microarrays. The distribution of chromosome locations was studied and pathway analysis of the identified sex-specific miRNAs in the placenta was carried out. Of the total 2558 miRNAs on the array, 597 miRNAs were expressed in over 70% of the samples and were included for further analyses. A total of 142 miRNAs were significantly (FDR<0.05) associated with the newborn's sex. In newborn girls, 76 miRNAs had higher expression (hsa-miR-361-5p as most significant) and 66 miRNAs had lower expression (hsa-miR-4646-5p as most significant) than in newborn boys. In the same study population, placental differentially expressed genes by sex were also identified using a whole genome approach. The placental gene expression revealed 27 differentially expressed genes by comparing girls to boys. Ultimately, we studied the miRNA-RNA interactome and identified 14 miRNA-mRNA interactions as sex-specific. Sex differences in placental m(i)RNA expression may reveal sex-specific patterns already present during pregnancy, which may influence physiological conditions in early or later life. These molecular processes might play a role in sex-specific disease susceptibility in later life.

The impact of maternal asthma during pregnancy on fetal growth and development: a review

INTRODUCTION

Asthma is a highly prevalent co-morbidity during pregnancy that can worsen as gestation progresses and is associated with several adverse perinatal outcomes. These adverse outcomes often result from uncontrolled asthma during pregnancy and acute asthma exacerbations that are associated with alterations in placental function and fetal growth.

AREAS COVERED

This paper will discuss how maternal asthma in pregnancy affects fetal growth and development which may alter future offspring health. Changes in placental function occur in a sex-specific manner in pregnancies complicated by asthma and result in differences in fetal growth and development which may influence child health. The follow up of children from mothers with asthma suggests they are at greater risk of developing asthma, have alterations in microvascular structure that may contribute to a future risk of cardiovascular disease and epigenetic modifications in immune cell function. The current evidence suggests that appropriately managed asthma during pregnancy results in normal fetal growth and development.

EXPERT OPINION

Clinical management of asthma during pregnancy needs significant improvement to prevent adverse outcomes for the fetus. The key to improving maternal and fetal outcomes is through education of health professionals and parents about controlling asthma during pregnancy.

Progestins Inhibit Interleukin-1β-Induced Matrix Metalloproteinase 1 and Interleukin 8 Expression via the Glucocorticoid Receptor in Primary Human Amnion Mesenchymal Cells

Preterm premature rupture of membranes is a leading cause of preterm births. Cytokine induced matrix metalloproteinase1 and interleukin 8 production from amnion mesenchymal cells may contribute to fetal membrane weakening and rupture. Progestins inhibit inflammation induced fetal membrane weakening but their effect on the inflammatory response of amnion mesenchymal cells is unknown. This study was designed to determine the role of progesterone receptor membrane component 1 and the glucocorticoid receptor in mediating the effects of progestins on interleukin-1β induced matrix metalloproteinase 1 and interleukin-8 expression in human amnion mesenchymal cells. Primary amnion mesenchymal cells harvested from human fetal membranes were passaged once and treated with vehicle, progesterone or medroxyprogesterone acetate at 10-6 M for 1 h followed by stimulation with interleukin-1β at 1 ng/ml for 24 h. Medroxyprogesterone acetate but not progesterone inhibited interleukin-1β-induced interlukin-8 and matrix metalloproteinase 1 mRNA expression. In subsequent dose response studies, medroxyprogesterone acetate, but not progesterone, at doses of 10-6-10-8 M inhibited interleukin-1β induced interleukin-8 and matrix metalloproteinase 1 mRNA expression. We further demonstrated that inhibition of glucocorticoid receptor expression, but not progesterone receptor membrane component 1 knockdown with small interfering RNA transfection, resulted in a reversal in medroxyprogesterone acetate's (10-7 M) inhibition of interleukin-1β- induced matrix metalloproteinase 1 mRNA expression and interleukin-8 mRNA expression and protein expression. Our findings demonstrate that medroxyprogesterone acetate exerts its anti-inflammatory effect primarily through the glucocorticoid receptor in human amnion mesenchymal cells. Modulation of glucocorticoid receptor signaling pathways maybe a useful therapeutic strategy for preventing inflammation induced fetal membrane weakening leading to preterm premature rupture of membranes.

Sex-specific epigenetic gene activation profiles are differentially modulated in human placentas affected by intrauterine growth restriction

BACKGROUND

The purpose of this study was to investigate the sex specific expression of histone protein modifications responsible for rapid gene expression in IUGR placentas.

PATIENTS AND METHODS

We screened for fetal sex-specific expression of the histone proteins H3K4me3 and H3K9ac in 23 IUGR and 40 control placentas via immunohistochemistry. The trophoblast-like cell line BeWo was used in order to analyze a potential effect of stimulation with prednisolone on H3K4me3 and H3K9ac in vitro. Calculating regression models with additional adjustment for potential confounders were used.

RESULTS

A significantly decreased level of H3K4me3 was detectable in female syncytiotrophoblasts, whereas H3K9ac was reduced predominantly in male extravillous throphoblast (EVT). No association to the gestational age existed.

CONCLUSION

Our data showed a reduced expression of the histone proteins H3K4me3 (female) and H3K9ac (male) in IUGR, furthermore elevated cortisol levels may lead to a sex-specific down-regulation of histone proteins in IUGR placentas.

The role of xenobiotic-metabolizing enzymes in the placenta: a growing research field

Introduction: The placenta is a temporary and unique organ that allows for the physical connection between a mother and fetus; this organ regulates the transport of gases and nutrients mediating the elimination of waste products contained in the fetal circulation. The placenta performs metabolic and excretion functions, on the basis of multiple enzymatic systems responsible for the oxidation, reduction, hydrolysis, and conjugation of xenobiotics. These mechanisms give the placenta a protective role that limits the fetal exposure to harmful compounds. During pregnancy, some diseases require uninterrupted treatment even if it is detrimental to the fetus. Drugs and other xenobiotics alter gene expression in the placenta with repercussions for the fetus and mother's well-being.Areas covered: This review provides a brief description of the human placental structure and function, the main drug and xenobiotic transporters and metabolizing enzymes, placenta-metabolized substrates, and alterations in gene expression that the exposure to xenobiotics may cause.Expert opinion: Research should be focused on the identification and validation of biological markers for the assessment of the harmful effects of some drugs in pregnancy, including the evaluation of polymorphisms and methylation patterns in chorionic villous samples and/or amniotic fluid.

Placental glucocorticoid receptors are not affected by maternal depression or SSRI treatment

Background: Prenatal depression is common, with an estimate that up to one in five pregnant women suffers from depressive symptoms. Maternal depression is associated with poor pregnancy outcomes such as preterm birth and low birth-weight. Such outcomes possibly affect offspring development. Previous studies suggest placental RNA levels of the glucocorticoid receptor are altered by maternal depression or anxiety; this stress may affect the placenta of male and female foetuses differently. However, it is unknown if the protein levels and activity of this receptor are additionally affected in women with depressive symptoms or being pharmacologically treated for depression.Methods: In this study, we investigated whether the glucocorticoid receptor (NR3C1) in the placenta is affected by maternal depression and/or selective serotonin reuptake inhibitor (SSRIs) treatment. Placentas from 45 women with singleton, term pregnancies were analysed by Western blot to determine glucocorticoid receptor levels, and by DNA-binding capacity to measure glucocorticoid receptor activation.Results: There were no differences in levels of the glucocorticoid receptor or activity between groups (control, depressive symptoms, and SSRI treatment; n = 45). Similarly, there was no difference in placental glucocorticoid receptor levels or activity dependent upon foetal sex.Conclusion: Maternal depression and SSRI treatment do not affect the glucocorticoid receptors in the placenta.

Intergenerational Influence of Antenatal Betamethasone on Growth, Growth Factors, and Neurological Outcomes in Rats

Antenatal steroids suppress growth in the fetus and newborn. Although weight deficits are regained by weaning, studies show that intrauterine growth restriction with postnatal "catch-up" growth is a risk factor for hypertension, insulin resistance, and ischemic heart disease in adult life, with multigenerational consequences. We tested the hypothesis that fetal exposure to betamethasone suppresses fetal growth in the F1 pups and their untreated F2 offspring. Timed pregnant rats received a single two-dose course of intramuscular betamethasone (0.25 mg/kg/day) on days 17 and 18 of gestation. Matched controls received equivalent volumes sterile normal saline. The first-generation (F1) offspring were studied at term, P21, and P70, or mated at P60 to produce the following subgroups: (1) saline male/saline female (SM/SF), (2) betamethasone (B) male/BFemale (BM/BF), (3) BM/SF, and (4) SM/BF. The unexposed second-generation (F2) offspring were examined at birth and P70. Growth, neurological outcomes, and growth factors were determined. At birth, the F1 pups exposed to B were significantly growth suppressed compared with the controls, with correspondingly lower blood glucose, insulin, IGF-I, corticosterone, and leptin levels and delayed neurological outcomes. Catchup growth occurred at P21, surpassing that of the control group. By P70, growth was comparable, but glucose was higher, insulin was lower, and memory was retarded in the B group, and transmitted to the unexposed F2 offspring of B-exposed rats. Antenatal betamethasone has sustained metabolic and neurological effects that may impact the unexposed offspring. Whether these intergenerational effects reverse in future generations remain to be determined.

Substrates and Clearance Products of Fetal Adrenal Glucocorticoid Synthesis in Full-Term Human Umbilical Circulation

In full-term elective caesarian sections, fetal flow of adrenal substrate steroids to products differs by sex, with males (M) in molar equilibrium whereas females (F) add net molarity and synthesize more cortisol. Using the same sampling design, paired, full-term, arterial, and venous umbilical cord samples and intrapartum chart records were obtained at the time of vaginal delivery (N = 167, 85 male) or emergency C-section (N = 38, 22 male). Eight steroids were quantified by liquid chromatography coupled to tandem mass spectrometry (adrenal glucocorticoids [cortisol, corticosterone], sequential cortisol precursor steroids [17-hydroxyprogesterone, 11-deoxycortisol], cortisol and corticosterone metabolites [cortisone and 11-dehydrocorticosterone], and gonadal steroids [androstenedione, testosterone]). Fetal sex was not significant in any analytic models. Going through both phase 1 and phase 2 labor increased fetal adrenal steroidogenesis and decreased male testosterone relative to emergency C-sections that do not reach stage 2 of labor (ie, head compressions) and elective C-sections with no labor. Sum adrenal steroid molarity arriving in venous serum was almost double the equivalent metric for deliveries without labor. No effects of operative vaginal delivery were noted. Maternal regional anesthetic suppressed venous concentrations, and fetal synthesis replaced that steroid. Approximate molar equivalence between substrate pool depletion and net glucocorticoid synthesis was seen. Paired venous and arterial umbilical cord serum has the potential to identify sex differences that underlie antenatal programming of hypothalamic-pituitary-adrenal axis function in later life. However, stage 2 labor before the collection of serum, and regional anesthetic for the mother, mask those sex differences.

Prenatal maternal stress and birth outcomes in rural Ghana: sex-specific associations

Background

In developed countries, prenatal maternal stress has been associated with poor fetal growth, however this has not been evaluated in rural sub-Saharan Africa. We evaluated the effect of prenatal maternal stress on fetal growth and birth outcomes in rural Ghana.

Methods

Leveraging a prospective, rural Ghanaian birth cohort, we ascertained prenatal maternal negative life events, categorized scores as 0-2 (low stress; referent), 3-5 (moderate), and > 5 (high) among 353 pregnant women in the Kintampo North Municipality and Kintampo South District located within the middle belt of Ghana. We employed linear regression to determine associations between prenatal maternal stress and infant birth weight, head circumference, and length. We additionally examined associations between prenatal maternal stress and adverse birth outcome, including low birth weight, small for gestational age, or stillbirth. Effect modification by infant sex was examined.

Results

In all children, high prenatal maternal stress was associated with reduced birth length (β = − 0.91, p = 0.04; p-value for trend = 0.04). Among girls, moderate and high prenatal maternal stress was associated with reduced birth weight (β = − 0.16, p = 0.02; β = − 0.18, p = 0.04 respectively; p-value for trend = 0.04) and head circumference (β = − 0.66, p = 0.05; β = − 1.02, p = 0.01 respectively; p-value for trend = 0.01). In girls, high prenatal stress increased odds of any adverse birth outcome (OR 2.41, 95% CI 1.01-5.75; p for interaction = 0.04). Sex-specific analyses did not demonstrate significant effects in boys.

Conclusions

All infants, but especially girls, were vulnerable to effects of prenatal maternal stress on birth outcomes. Understanding risk factors for impaired fetal growth may help develop preventative public health strategies.

Trial registration

NCT01335490 (prospective registration).

Date of Registration: April 14, 2011.

Status of Registration: Completed.

Placental glucocorticoid receptor isoforms in a sheep model of maternal allergic asthma

Maternal asthma increases the risk of adverse pregnancy outcomes and may affect fetal growth and placental function by differential effects on the expression of glucocorticoid receptor (GR) isoforms, leading to altered glucocorticoid signalling. Our aim was to examine the effect of maternal asthma on placental GR profiles using a pregnant sheep model of asthma. Nine known GR isoforms were detected. There was a significant increase in the expression of placental GR isoforms that are known to have low trans-activational activity in other species including GR A, GR P and GRγ which may result in a pro-inflammatory environment in the presence of allergic asthma.

Glucocorticoid receptors α and β are modulated sex specifically in human placentas of intrauterine growth restriction (IUGR)

PURPOSE

The objective of this study was to analyze the expression of the glucocorticoid receptor (GR) subtypes GRα and GRβ in placentas affected by intrauterine growth restriction (IUGR).

METHODS

We analyzed the sex-specific placental expression of GRα and GRβ in 23 IUGR and 40 control placentas using immunohistochemistry and immunofluorescence. The GR gene, also known as nuclear receptor subfamily 3 group C member 1 (NR3C1), mRNA production in trophoblast-like cell line BeWo after stimulation with prednisolone was analyzed using quantitative polymerase chain reaction (qPCR) and on the protein level using western blot analysis.

RESULTS

GR subtypes showed a sex-specific upregulation in placentas from IUGR compared to control placentas. An increased expression of GRα was detectable in female placental tissue, whereas GRβ was increased in males.

CONCLUSION

Our data support previous findings suggesting that the glucocorticoid metabolism plays a role in the pathophysiology of IUGR. Furthermore, the data suggest that the underlying molecular mechanisms differ between male and female cases.

Human placental androgen receptor variants: Potential regulators of male fetal growth

INTRODUCTION

Numerous studies show that males have increased intrauterine growth compared to females, and that pregnancy complications may further these growth differences, but the regulatory mechanisms underlying these differences remain unknown. We propose that these growth outcomes may be due to sex-specific differences in androgen sensitivity - giving rise to altered growth signalling pathways - mediated by the differential expression of placental androgen receptor (AR) variants.

METHODS

Placental protein and mRNA were used to identify AR protein variant levels and AR-downstream target gene expression, and were then analysed against neonatal measurements. Dihydrotestosterone (DHT)-induced AR protein variant expression and downstream growth factors were examined in vitro.

RESULTS

Four known AR variants (AR-FL, AR-V1, AR-V7, and AR-45), and three unknown proteins (120, 90 and 55 kDa) immunoreactive to the anti-AR antibody were identified in human placentae. Male placentae from controlled asthmatic pregnancies had increased AR-45 and decreased AR-V1 and AR-V7 nuclear expression. Increased nuclear AR-45 expression was associated with increased insulin-like growth factor 1 (IGF-1), IGF-1 receptor (IGF-1R), and IGF-binding protein 5 (IGFBP-5) mRNA expression and normal male growth. AR-45 mRNA and protein did not change in the presence of uncontrolled maternal asthma and associated with an increase in small for gestational (SGA) male fetuses. In vitro DHT stimulation increased AR-45 protein and IGF-1R and IGFBP-5 mRNA expression.

CONCLUSIONS

Collectively, our data shows altered AR protein expression and downstream signalling targets may contribute to sex-specific fetal growth outcomes in response to an adverse environment, and that AR-45 appears central in mediating these changes.

Maternal Cortisol Concentrations During Pregnancy and Sex-Specific Associations With Neonatal Amygdala Connectivity and Emerging Internalizing Behaviors

BACKGROUND

Maternal cortisol during pregnancy has the potential to influence rapidly developing fetal brain systems that are commonly altered in neurodevelopmental and psychiatric disorders. Research examining maternal cortisol concentrations across pregnancy and offspring neurodevelopment proximal to birth is needed to advance understanding in this area and lead to insight into the etiology of these disorders.

METHODS

Participants were 70 adult women recruited during early pregnancy and their infants born after 34 weeks gestation. Maternal cortisol concentrations were assessed serially over 4 days in early, mid, and late gestation. Resting state functional connectivity magnetic resonance imaging of the neonatal amygdala was examined. Mothers reported on children's internalizing behavior problems at 24 months of age.

RESULTS

Maternal cortisol concentrations during pregnancy were significantly associated with neonatal amygdala connectivity in a sex-specific manner. Elevated maternal cortisol was associated with stronger amygdala connectivity to brain regions involved in sensory processing and integration, as well as the default mode network in girls, and with weaker connectivity to these brain regions in boys. Elevated maternal cortisol was associated with higher internalizing symptoms in girls only, and this association was mediated by stronger neonatal amygdala connectivity.

CONCLUSIONS

Normative variation in maternal cortisol during pregnancy is associated with the coordinated functioning of the amygdala soon after birth in a sex-specific manner. The identified pathway from maternal cortisol to higher internalizing symptoms in girls via alterations in neonatal amygdala connectivity may be relevant for the etiology of sex differences in internalizing psychiatric disorders, which are more prevalent in women.

Placental glucocorticoid receptor and 11β-hydroxysteroid dehydrogenase-2 recruitment indicates impact of prenatal adversity upon postnatal development in mice

Prenatal stress may increase concentrations of maternal glucocorticoids, which restrict fetal growth, with variable impact upon postnatal development. Among key regulators of stress hormone effects are the glucocorticoid receptor (GR) and 11β-hydroxysteroid dehydrogenase-2 (11βHSD2), the enzyme that inactivates glucocorticoid. This study utilized mice selectively bred for social dominance (Dom) or submissiveness (Sub), respectively exhibiting resilience or sensitivity to stress, to test whether stress-induced alterations in placental GR and 11βHSD2 protein expression may mediate divergent effects of prenatal adversity upon postnatal development. Pregnant Dom and Sub dams underwent prenatal restraint stress (PRS) for 45 min on gestational days (GD) 15-17. PRS induced a similar spike in serum corticosterone concentrations of dams from each strain on GD15 (p < .001, n = 8), and impaired fetal growth (p < .01, n = 5 litters), although Dom placentae were larger than Sub placentae (p < .01). Among placentae from Dom dams, PRS elevated protein contents of both GR (p < .05, n = 5 litters) and 11βHSD2 (p < .01) on GD19. In contrast, GR contents were reduced among placentae from PRS-exposed Sub mice (p < .01), without changes in 11βHSD2 content. Correspondingly, Dom PRS pup growth recovered by PND14, yet Sub PRS pups remained underweight into adolescence (p < .0001, n = 40 pups). Thus, prenatal stress more strongly increased placental GR and 11βHSD2 levels among Dom mice than in Subs. Increased GR may improve placental function and up-regulate 11βHSD2 expression, protecting fetuses from effects of prenatal stress upon postnatal development. Placental recruitment of GR and 11βHSD2 are potential markers of stress-induced developmental disorders, in accordance with maternal resilience or sensitivity to stress.

Microvascular circulatory dysregulation driven in part by cystathionine gamma-lyase: A new paradigm for cardiovascular compromise in the preterm newborn

OBJECTIVE

H₂ S may explain the dysregulation of microvascular tone associated with poor outcome following preterm birth. In adult vasculature, H₂ S is predominantly produced by CSE. We hypothesized that vascular CSE activity contributes to microvascular tone regulation during circulatory transition.

METHODS

Preterm (GA62) and full-term (GA69) guinea pig fetuses and neonates were studied. Microvascular blood flow was assessed by laser Doppler flowmetry. Thiosulfate, primary urinary metabolite of H₂ S, was determined by high-performance liquid chromatography. Real-time H₂ S production was assessed using a microrespiration system in fetal and postnatal (10, 24 hours) skin and heart samples. CSE contribution was investigated by inhibition via propargylglycine.

RESULTS

In preterm animals, postnatal H₂ S production capacity in peripheral vasculature increased significantly and was significantly reduced by the inhibition of CSE. Urinary thiosulfate correlated with both microvascular blood flow and capacity of the vasculature to produce H₂ S. H₂ S produced via CSE did not correlate directly with microvascular blood flow.

CONCLUSIONS

In preterm neonates, H₂ S production increases during fetal-to-neonatal transition and CSE contribution to total H₂ S increases postnatally. CSE-dependent mechanisms may therefore underpin the increase in H₂ S production over the first 72 hours of life in preterm human neonates, associated with both central and peripheral cardiovascular instability.

Natural disaster-related prenatal maternal stress is associated with alterations in placental glucocorticoid system: The QF2011 Queensland Flood Study

We investigated the effects of a natural disaster (a sudden flood) as a source of prenatal maternal stress (PNMS) on the placental glucocorticoid system and glucose transporters. Whether the gestational age at the time of the flood moderated these effects was also evaluated. Placental samples were collected from participants in the 2011 Queensland Flood Study (QF2011) who were pregnant in the first or second trimester at the onset of the flood. Detailed questionnaire results for objective hardship and composite subjective distress were obtained to assess stress levels. Subjective distress was significantly associated with a reduction in placental NR3C1-β mRNA levels for males only (β = -0.491, p = 0.005). In female placentas, objective hardship was marginally linked with lower SLC2A1 mRNA levels while subjective distress was a marginally significant predictor of higher placental SLC2A4 mRNA levels. Gestational age at the time of the flood was a significant moderator of the effect of subjective distress on placental mRNA levels for NR3C1-α (p = 0.046) and HSD11B1 (p = 0.049) in male placentas: if the flood occurred in mid-pregnancy, lower subjective distress predicted higher HSD11B1 while higher subjective distress predicted lower NR3C1-α placental mRNA level. While results did not show any PNMS effects on placental HSD11B2 mRNA and protein levels, and activity, we showed a reduction in placental NR3C1-β mRNA level in male placentas. Our results show evidence of distinct placental glucocorticoid and glucose systems adaptations to PNMS as a function of fetal sex and gestational timing of exposure, with high subjective PNMS in mid-pregnancy associated with lower levels of expression of glucocorticoid-promoting gene in males, leaving the fetus less protected against maternal stress. The exact mechanism by which natural disaster-related PNMS acts on the placenta and the impact on fetal programming requires further investigation.

DNA methylation of the glucocorticoid receptor gene promoter in the placenta is associated with blood pressure regulation in human pregnancy

BACKGROUND

Blood pressure (BP) regulation during pregnancy is influenced by hormones of placental origin. It was shown that the glucocorticoid system is altered in hypertensive pregnancy disorders such as preeclampsia. Epigenetic mechanism might influence the activity of genes involved in placental hormone/hormone receptor synthesis/action during pregnancy.

METHOD

In the current study, we analyzed the association of 5'-C-phosphate-G-3' (CpG) site methylation of different glucocorticoid receptor gene (NR3C1) promoter regions with BP during pregnancy. The study was performed as a nested case-control study (n = 80) out of 1045 mother/child pairs from the Berlin Birth Cohort. Placental DNA was extracted and bisulfite converted. Nested PCR products from six NR3C1 proximal promoter regions [glucocorticoid receptor gene promotor region B (GR-1B), C (GR-1C), D (GR-1D), E (GR-1E), F (GR-1F), and H (GR-1H)] were analyzed by next generation sequencing.

RESULTS

NR3C1 promoter regions GR-1D and GR-1E had a much higher degree of DNA methylation as compared to GR-1B, GR-1F or GR-1H when analyzing the entire study population. Comparison of placental NR3C1 CpG site methylation among hypotensive, normotensive and hypertensive mothers revealed several differently methylated CpG sites in the GR-1F promoter region only. Both hypertension and hypotension were associated with increased DNA methylation of GR-1F CpG sites. These associations were independent of confounding factors, such as family history of hypertension, smoking status before pregnancy and prepregnancy BMI. Assessment of placental glucocorticoid receptor expression by western blot showed that observed DNA methylation differences were not associated with altered levels of placental glucocorticoid receptor expression. However, correlation matrices of all NR3C1 proximal promoter regions demonstrated different correlation patterns of intraregional and interregional DNA methylation in the three BP groups, putatively indicating altered transcriptional control of glucocorticoid receptor isoforms.

CONCLUSION

Our study provides evidence of an independent association between placental NR3C1 proximal promoter methylation and maternal BP. Furthermore, we observed different patterns of NR3C1 promoter methylation in normotensive, hypertensive and hypotensive pregnancy.

Cortisol inhibits CSF2 and CSF3 via DNA methylation and inhibits invasion in first-trimester trophoblast cells

PROBLEM

Heightened maternal stress affects trophoblast function and increases risk for adverse pregnancy outcomes.

METHODS OF STUDY

Studies were performed using the first-trimester trophoblast cell line, Sw.71. Cytokines were quantified using qPCR and ELISA. Epigenetic regulation of cytokines was characterized by inhibiting histone deacetylation (1 μmol/L suberoylanilide hydroxamic acid [SAHA]) or methylation (5 μmol/L 5-azacytidine), or with chromatin immunoprecipitation (ChIP) with a pan-acetyl histone-3 antibody. Invasion assays used Matrigel chambers.

RESULTS

Cortisol inhibited expression of CSF2 (GM-CSF) and CSF3 (G-CSF) in trophoblast cells. Cortisol-associated inhibition was dependent on DNA methylation and was not affected by acetylation. There was also a modest decrease in trophoblast invasion, not dependent on loss of CSFs.

CONCLUSION

In first-trimester trophoblast cells, the physiological glucocorticoid, cortisol, inhibited two cytokines with roles in placental development and decreased trophoblast invasion. Cortisol-associated changes in trophoblast function could increase the risk for immune-mediated abortion or other adverse pregnancy outcomes.

Dexamethasone and sex regulate placental glucocorticoid receptor isoforms in mice

Maternal dexamethasone exposure in the mouse impairs placental development and programs adult disease in a sexually dimorphic manner. Glucocorticoids bind to different glucocorticoid receptor (GR) isoforms to regulate gene transcription and cellular signaling. We hypothesized that sexually dimorphic placental responses to glucocorticoids are due to differences in GR isoforms present in the placenta. Pregnant C57Bl6 mice were exposed to saline or dexamethasone from E12.5 until E14.5 (1 µg/kg/h) before the collection of placentae. Cytoplasmic and nuclear protein fractions were extracted from placentae of male and female fetuses for Western blot analysis of GR isoforms. Eight known isoforms of the GR were detected in the mouse placenta including the translational isoforms GRα-A, B, C and D1-3 and the splice variants GRA and GRP. The expression of GRA, GRP and each of the GRα isoforms were altered by dexamethasone in relation to fetal sex and cellular location. Placentae of female fetuses had higher GRα-A and GRP expression in the cytoplasm than males, and GRα-C was more highly expressed in the nucleus of females than that in males. Dexamethasone significantly increased the cytoplasmic expression of GRα-A, but reduced the expression of GRα-C in placentae of males. Dexamethasone increased the expression of the GRα-C-regulated genes Sgk1 and Bcl2l11, particularly in females. The cleaved caspase-3 staining in placental sections indicated GRα-C may mediate sex differences in dexamethasone-induced apoptosis. These findings may underlie the sex-specific placental adaptations that regulate different growth profiles in males and females and different risks for programmed disease outcomes in offspring.

Glucocorticoids and Reproduction: Traffic Control on the Road to Reproduction

Glucocorticoids are steroid hormones that regulate diverse cellular functions and are essential to facilitate normal physiology. However, stress-induced levels of glucocorticoids result in several pathologies including profound reproductive dysfunction. Compelling new evidence indicates that glucocorticoids are crucial to the establishment and maintenance of reproductive function. The fertility-promoting or -inhibiting activity of glucocorticoids depends on timing, dose, and glucocorticoid responsiveness within a given tissue, which is mediated by the glucocorticoid receptor (GR). The GR gene and protein are subject to cellular processing, contributing to signaling diversity and providing a mechanism by which both physiological and stress-induced levels of glucocorticoids function in a cell-specific manner. Understanding how glucocorticoids regulate fertility and infertility may lead to novel approaches to the regulation of reproductive function.

Effects of prenatal exposure to endocrine disruptors and toxic metals on the fetal epigenome

Exposure to environmental contaminants during pregnancy has been linked to adverse outcomes at birth and later in life. The link between prenatal exposures and latent health outcomes suggests that these exposures may result in long-term epigenetic reprogramming. Toxic metals and endocrine disruptors are two major classes of contaminants that are ubiquitously present in the environment and represent threats to human health. In this review, we present evidence that prenatal exposures to these contaminants result in fetal epigenomic changes, including altered global DNA methylation, gene-specific CpG methylation and microRNA expression. Importantly, these changes may have functional cellular consequences, impacting health outcomes later in life. Therefore, these epigenetic changes represent a critical mechanism that warrants further study.

Effects of prenatal exposure to endocrine disruptors and toxic metals on the fetal epigenome

Exposure to environmental contaminants during pregnancy has been linked to adverse outcomes at birth and later in life. The link between prenatal exposures and latent health outcomes suggests that these exposures may result in long-term epigenetic reprogramming. Toxic metals and endocrine disruptors are two major classes of contaminants that are ubiquitously present in the environment and represent threats to human health. In this review, we present evidence that prenatal exposures to these contaminants result in fetal epigenomic changes, including altered global DNA methylation, gene-specific CpG methylation and microRNA expression. Importantly, these changes may have functional cellular consequences, impacting health outcomes later in life. Therefore, these epigenetic changes represent a critical mechanism that warrants further study.

Review: Placental adaptations to the presence of maternal asthma during pregnancy

Asthma is a highly prevalent chronic medical condition affecting an estimated 12% of pregnant, women each year, with prevalence of asthma greatest (up to 16%) among the socially disadvantaged. Maternal asthma is associated with significant perinatal morbidity and mortality including preterm births, neonatal hospitalisations and low birthweight outcomes each year. We have identified that the placenta adapts to the presence of chronic, maternal asthma during pregnancy in a sex specific manner that may confer sex differences in fetal outcome. The male fetus was at greater risk of a poor outcome than a female fetus in the presence of maternal asthma and an acute inflammatory event such as an asthma exacerbation. This review will examine the role of sex specific differences in placental function on fetal growth and survival.

Sex differences in early-life programming of the hypothalamic-pituitary-adrenal axis in humans suggest increased vulnerability in females: a systematic review

Fetal glucocorticoid overexposure is a key mechanism linking early development with later-life disease. In humans, low birth weight associates with increased fasting cortisol, hypothalamic-pituitary-adrenal (HPA) axis reactivity, and with cardiovascular risk and cognitive decline. As there are sex differences in these adult diseases, we hypothesized that there may be sex differences in programming of the HPA axis in response to prenatal stressors. We conducted a systematic review following Meta-Analysis of Observational Studies in Epidemiology and Preferred Reporting Items for Systematic Reviews and Meta-Analysis. We searched Embase, MEDLINE and Web of Science from inception to 31 October 2016. We included studies related to sex differences, prenatal exposures and HPA axis. We excluded studies investigating specific disease states. The 23 included studies investigated the consequences of low birth weight, preterm birth and maternal stressors of asthma, psychosocial stress and glucocorticoid medications on HPA axis outcomes of placental glucocorticoid biology and offspring HPA axis function in early life and later life. Female offspring exposed to stressors had increased HPA axis reactivity compared with males. Furthermore, the female placenta increased its permeability to maternal glucocorticoids following maternal stress with changes in the expression of 11β-hydroxysteroid dehydrogenase enzymes in response to maternal glucocorticoid exposure or asthma. Among males there was some evidence of altered diurnal cortisol secretion. We conclude that although there is some evidence of male vulnerability leading to altered diurnal cortisol secretion, the female HPA axis is more vulnerable to programming, particularly in terms of its reactivity; this suggests a mechanism underlying sex differences in later-life diseases.

Mechanisms of Glucocorticoid Action During Development

Glucocorticoids are primary stress hormones produced by the adrenal cortex. The concentration of serum glucocorticoids in the fetus is low throughout most of gestation but surge in the weeks prior to birth. While their most well-known function is to stimulate differentiation and functional development of the lungs, glucocorticoids also play crucial roles in the development of several other organ systems. Mothers at risk of preterm delivery are administered glucocorticoids to accelerate fetal lung development and prevent respiratory distress. Conversely, excessive glucocorticoid signaling is detrimental for fetal development; slowing fetal and placental growth and programming the individual for disease later in adult life. This review explores the mechanisms that control glucocorticoid signaling during pregnancy and provides an overview of the impact of glucocorticoid signaling on fetal development.

ALL OUR SONS: THE DEVELOPMENTAL NEUROBIOLOGY AND NEUROENDOCRINOLOGY OF BOYS AT RISK

Why are boys at risk? To address this question, I use the perspective of regulation theory to offer a model of the deeper psychoneurobiological mechanisms that underlie the vulnerability of the developing male. The central thesis of this work dictates that significant gender differences are seen between male and female social and emotional functions in the earliest stages of development, and that these result from not only differences in sex hormones and social experiences but also in rates of male and female brain maturation, specifically in the early developing right brain. I present interdisciplinary research which indicates that the stress-regulating circuits of the male brain mature more slowly than those of the female in the prenatal, perinatal, and postnatal critical periods, and that this differential structural maturation is reflected in normal gender differences in right-brain attachment functions. Due to this maturational delay, developing males also are more vulnerable over a longer period of time to stressors in the social environment (attachment trauma) and toxins in the physical environment (endocrine disruptors) that negatively impact right-brain development. In terms of differences in gender-related psychopathology, I describe the early developmental neuroendocrinological and neurobiological mechanisms that are involved in the increased vulnerability of males to autism, early onset schizophrenia, attention deficit hyperactivity disorder, and conduct disorders as well as the epigenetic mechanisms that can account for the recent widespread increase of these disorders in U.S. culture. I also offer a clinical formulation of early assessments of boys at risk, discuss the impact of early childcare on male psychopathogenesis, and end with a neurobiological model of optimal adult male socioemotional functions.

Full-term deliveries without antecedent labor reveal sex differences in umbilical cord glucocorticoid concentrations

BACKGROUND

Previous studies have shown that pregnant women have higher salivary cortisol levels when the fetus is female. These findings suggest a basis for the sex differences observed in many offspring outcomes after exposure to in utero stress, but it is not known if fetal adrenal glucocorticoid synthesis differs by sex.

METHODS

Arterial and venous umbilical cord blood samples were collected immediately after scheduled cesarean delivery (n=52, 25 female). Cortisol and corticosterone concentrations were quantified by liquid chromatography coupled to tandem mass spectrometry.

RESULTS

Sex differences were observed for fetal arterial and venous cortisol and venous corticosterone, with higher levels present when the fetus was female. However, sex differences were not observed for fetal synthesis of cortisol, suggesting that the fetus does not control the differences observed in cord blood glucocorticoids.

CONCLUSIONS

The presence of sex differences in umbilical cord glucocorticoid concentrations in the absence of sex differences in glucocorticoid synthesis by the fetal adrenal gland suggests that these differences have a maternal or placental origin. Thus, the in utero glucocorticoids in circulation are sex-specific and may have developmental importance for sex differences in psychiatric and neurodevelopment disorders that display sex biases.

Sexually dimorphic and interactive effects of prenatal maternal cortisol and psychological distress on infant cortisol reactivity

In utero exposure to maternal psychological distress is a risk factor for developmental psychopathology, and these effects are believed to partially occur via dysregulation of the maternal and fetal hypothalamus-adrenal-pituitary axes. Nevertheless, only a few human studies have directly assessed the effects of prenatal cortisol exposure on infant cortisol reactivity, and none have investigated sex differences or potential interactions between prenatal cortisol and psychological distress. Here we report on a prospective longitudinal investigation (N = 236) of in utero exposure to maternal cortisol and distress in a relatively high socioeconomic status and low-risk population to determine whether these exposures interact in their effects on infant (M age = 3.0 months, range = 2.3-5.0 months, 51.9% male) cortisol reactivity and whether there are sex differences in these effects. Results revealed both sexually dimorphic and interactive effects of prenatal cortisol and distress, even after controlling for postnatal distress. In general, blunted reactivity in females was associated with exposure to high maternal distress and flattened patterns of diurnal maternal cortisol, whereas blunted reactivity in males was associated with exposure to steeper morning increases and daytime decreases in maternal cortisol. The findings suggest that sex differences in the effects of prenatal cortisol and distress on infant cortisol reactivity are a plausible mechanism by which maternal experiences during pregnancy contribute to sex differences in the development of psychopathology.

A sexually dichotomous, autistic-like phenotype is induced by Group B Streptococcus maternofetal immune activation

Group B Streptococcus (GBS) is a commensal bacterium present in the lower genital tract of 15-30% of healthy pregnant women. GBS is the leading cause of chorioamnionitis and cerebral injuries in newborns, occurring most often in the absence of maternofetal pathogen translocation. Despite GBS being the most frequent bacterium colonizing pregnant women, no preclinical studies have investigated the impact of end-gestational maternal GBS exposure on the offspring's brain development and its behavioral correlates. Our hypothesis is that GBS-induced gestational infection/inflammation has a deleterious neurodevelopmental impact on uninfected offspring. Our goal was to study the impact of maternal GBS infection on the placental and neurodevelopmental features in the offspring using a new preclinical rat model. GBS-exposed placentas exhibited chorioamnionitis characterized by the presence of Gram-positive cocci and polymorphonuclear cells, with the latter being significantly more prominent in the labyrinth of male offspring. GBS-exposed male offspring had reduced thickness of periventricular white matter. In addition, they exhibited autistic-like behaviors, such as abnormal social interaction and communication, impaired processing of sensory information and hyperactivity. Overall, these data show for the first time that gestational exposure to GBS plays an important role in the generation of neurodevelopmental abnormalities reminiscent of human autism spectrum disorders (ASD). These results provide new evidence in favor of the role of a common and modifiable infectious/inflammatory environmental factor in human ASD pathophysiology. Autism Res 2017, 10: 233-245. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.