Differential expression of placental glucocorticoid receptors and growth arrest-specific transcript 5 in term and preterm pregnancies: evidence for involvement of maternal stress

From placenta to the foetus: a systematic review of in vitro models of stress- and inflammation-induced depression in pregnancy

BACKGROUND

Depression in pregnancy can increase vulnerability for psychiatric disorders in the offspring, likely via the transfer of heightened maternal cortisol and cytokines to the in-utero environment. However, the precise cellular and molecular mechanisms, are largely unclear. Animal studies can represent this complex pathophysiology at a systemic level but are expensive and ethically challenging. While simpler, in vitro models offer high-throughput opportunities. Therefore, this systematic review integrates findings of in vitro models relevant to depression in pregnancy, to generate novel hypotheses and targets for intervention.

METHODS

The systematic analysis covered studies investigating glucocorticoid or cytokine challenges on placental or foetal neural progenitor cells (NPCs), with or without co-treatment with sex hormones.

RESULTS

Of the 50 included studies, 11 used placental cells and 39 NPCs; surprisingly, only one used a combination of oestrogen and cortisol, and no study combined placental cells and NPCs. In placental cells, cortisol or cytokines decreased nutrient transporter expression and steroidogenic enzyme activity, and increased cytokine production. NPCs exhibited decreases in proliferation and differentiation, via specific molecular pathways, namely, inhibition of hedgehog signalling and activation of kynurenine pathway. In these cells, studies also highlighted epigenetic priming of stress and inflammatory pathways.

CONCLUSIONS

Overall, results suggest that stress and inflammation not only detrimentally impact placental regulation of nutrients and hormones to the foetus, but also activate downstream pathways through increased inflammation in the placenta, ultimately eliciting adverse effects on foetal neurogenesis. Future research should investigate how sex hormones regulate these mechanisms, with the aim of developing targeted therapeutic approaches for depression in pregnancy.

Influence of maternal psychological distress during COVID-19 pandemic on placental morphometry and texture

The Coronavirus Disease 2019 (COVID-19) pandemic has been accompanied by increased prenatal maternal distress (PMD). PMD is associated with adverse pregnancy outcomes which may be mediated by the placenta. However, the potential impact of the pandemic on in vivo placental development remains unknown. To examine the impact of the pandemic and PMD on in vivo structural placental development using advanced magnetic resonance imaging (MRI), acquired anatomic images of the placenta from 63 pregnant women without known COVID-19 exposure during the pandemic and 165 pre-pandemic controls. Measures of placental morphometry and texture were extracted. PMD was determined from validated questionnaires. Generalized estimating equations were utilized to compare differences in PMD placental features between COVID-era and pre-pandemic cohorts. Maternal stress and depression scores were significantly higher in the pandemic cohort. Placental volume, thickness, gray level kurtosis, skewness and run length non-uniformity were increased in the pandemic cohort, while placental elongation, mean gray level and long run emphasis were decreased. PMD was a mediator of the association between pandemic status and placental features. Altered in vivo placental structure during the pandemic suggests an underappreciated link between disturbances in maternal environment and perturbed placental development. The long-term impact on offspring is currently under investigation.

Genome-wide association study identifies a novel maternal gene × stress interaction associated with spontaneous preterm birth

BACKGROUND

Maternal stress is potentially a modifiable risk factor for spontaneous preterm birth (sPTB). However, epidemiologic findings on the maternal stress-sPTB relationship have been inconsistent.

METHODS

To investigate whether the maternal stress-sPTB associations may be modified by genetic susceptibility, we performed genome-wide gene × stress interaction analyses in 1490 African-American women from the Boston Birth cohort who delivered term (n = 1033) or preterm (n = 457) infants. Genotyping was performed using Illumina HumanOmni 2.5 array. Replication was performed using data from the NICHD genomic and Proteomic Network (GPN) for PTB research.

RESULTS

rs35331017, a T-allele insertion/deletion polymorphism in the protein-tyrosine phosphatase receptor Type D (PTPRD) gene, was the top hit that interacted significantly with maternal lifetime stress on risk of sPTB (P_G × E = 4.7 × 10^-8). We revealed a dose-responsive association between degree of stress and risk of sPTB in mothers carrying the insertion/insertion genotype, but an inverse association was observed in mothers carrying the heterozygous or deletion/deletion genotypes. This interaction was replicated in African-American (P_G × E = 0.088) and Caucasian mothers (P_G × E = 0.023) from the GPN study.

CONCLUSION

We demonstrated a significant maternal PTPRD × stress interaction on sPTB risk. This finding, if further confirmed, may provide new insight into individual susceptibility to stress-induced sPTB.

IMPACT

This was the first preterm study to demonstrate a significant genome-wide gene-stress interaction in African Americans, specifically, PTPRD gene variants can interact with maternal perceived stress to affect risk of spontaneous preterm birth. The PTPRD × maternal stress interaction was demonstrated in African Americans and replicated in both African Americans and Caucasians from the GPN study. Our findings highlight the importance of considering genetic susceptibility in assessing the role of maternal stress on spontaneous preterm birth.

Gaining a deeper understanding of social determinants of preterm birth by integrating multi-omics data

In the US, high rates of preterm birth (PTB) and profound Black-White disparities in PTB have persisted for decades. This review focuses on the role of social determinants of health (SDH), with an emphasis on maternal stress, in PTB disparity and biological embedding. It covers: (1) PTB disparity in US Black women and possible contributors; (2) the role of SDH, highlighting maternal stress, in the persistent racial disparity of PTB; (3) epigenetics at the interface between genes and environment; (4) the role of the genome in modifying maternal stress-PTB associations; (5) recent advances in multi-omics studies of PTB; and (6) future perspectives on integrating multi-omics with SDH to elucidate the Black-White disparity in PTB. Available studies have indicated that neither environmental exposures nor genetics alone can adequately explain the Black-White PTB disparity. Preliminary yet promising findings of epigenetic and gene-environment interaction studies underscore the value of integrating SDH with multi-omics in prospective birth cohort studies, especially among high-risk Black women. In an era of rapid advancements in biomedical sciences and technologies and a growing number of prospective birth cohort studies, we have unprecedented opportunities to advance this field and finally address the long history of health disparities in PTB. IMPACT: This review provides an overview of social determinants of health (SDH) with a focus on maternal stress and its role on Black-White disparity in preterm birth (PTB). It summarizes the available literature on the interplay of maternal stress with key biological layers (e.g., individual genome and epigenome in response to environmental stressors) and significant knowledge gaps. It offers perspectives that such knowledge may provide deeper insight into how SDH affects PTB and why some women are more vulnerable than others and underscores the critical need for integrating SDH with multi-omics in prospective birth cohort studies, especially among high-risk Black women.

Long Non-coding RNA Gas5 Is Associated With Preeclampsia and Regulates Biological Behaviors of Trophoblast via MicroRNA-21

Preeclampsia is a lethal pregnancy specific hypertensive disorder involving multisystem. Despite extensive studies to investigate the causes of preeclampsia, the pathogenesis still remains largely unknown. Long non-coding RNAs (lncRNAs) are a diverse class of non-translated RNAs which play a crucial part in various biological phenomena. Although lncRNA Growth Arrest-Specific 5 (GAS5) aberrantly expressed in multiple cancer tissues and is implicated in multiple biological processes of tumor cells, little is known about its role in preeclampsia. In this study, 40 patients with preeclampsia and 32 gestational age matched normotension pregnant women were recruited. Using quantitative real-time polymerase chain reaction (qRT-PCR), we found higher expression of GAS5 in placenta of preclamsia affected women. The level of GAS5 existed strongly in correlation with Thrombin Time indicating coagulation function and other clinical parameters by Pearson correlation analysis. Then we constructed the GAS5 lentivirus expression vectors and transfected into human trophoblast cell lines HTR-8/SVneo and JEG-3. Using in vitro cell culture studies, we found an inhibited effect of GAS5 on proliferative ability, migratory ability and invasive ability however; no effect on apoptosis was detected. Further mechanistic analysis found that GAS5 modulated microRNA-21 (miR-21) in an opposite variation tendency by qRT-PCR and rescue experiment. In addition, inhibition of GAS5 promoted the activation of PI3K/AKT signaling pathway and its downstream proteins covering MMP-9 and TP53 as evident from our qRT-PCR and western blot analyses. Thus, we suggested that GAS5 might involve in pregnancy with preeclampsia by influencing the biological functions of trophoblast cells through the regulation of miR-21 and activation of PI3K/AKT signaling pathway and its downstream targets, which may contribute to reveal the nature of preeclampsia.

Bone-strengthening supplement (BSP) promotes bone and cartilage repair, for the treatment of Osteonecrosis of Femoral Head: an MRI-based study

Currently, no effective drug treatment is available for bone and joint disease, a disorder of the bone and cartilage cells. Osteonecrosis of the femoral head (ONFH) is an example of bone and joint disease. It is progressive, with femoral head collapse resulting from the death of osteocytes and the bone marrow, leading to a poor quality of life and surgical interventions. However, the mechanism of this disease is still unknown, and the effects of current therapy are not satisfactory. In our previous study, we showed, using an ONFH rat model, that a new Chinese medicine, "bone-strengthening supplement" (BSP), enhances bone growth, promotes bone density, and restores blood circulation in the femoral head, and can significantly relieve pain, improve hip joint function, and reduce claudication. In the present study, we evaluated the curative effect of BSP in patients with ONFH using MRI with a double-blind randomized protocol. BSP significantly relieved pain unlike the control treatment; in addition, this treatment could improve MRI signal in ONFH patients. These results suggest that, overall; BSP can restore blood circulation and promote bone and cartilage growth during restoration of bone necrosis and the treatment of bone and joint disease.

Steroid receptors and their regulation in avian extraembryonic membranes provide a novel substrate for hormone mediated maternal effects

Exposure of the vertebrate embryo to maternal hormones can have long-lasting effects on its phenotype, which has been studied extensively by experimentally manipulating maternal steroids, mostly androgens, in bird eggs. Yet, there is a severe lack of understanding of how and when these effects are actually mediated, hampering both underlying proximate and ultimate explanations. Here we report a novel finding that the embryo expresses androgen receptor (AR) and estrogen receptor (ERα) mRNA in its extraembryonic membranes (EMs) as early as before its own hormone production starts, suggesting a novel substrate for action of maternal hormones on the offspring. We also report the first experimental evidence for steroid receptor regulation in the avian embryo in response to yolk steroid levels: the level of AR is dependent on yolk androgen levels only in the EMs but not in body tissues, suggesting embryonic adaptation to maternal hormones. The results also solve the problem of uptake of lipophilic steroids from the yolk, why they affect multiple traits, and how they could mediate maternal effects without affecting embryonic sexual differentiation.

Glucocorticoids modulate multidrug resistance transporters in the first trimester human placenta

The placental multidrug transporters, P‐glycoprotein (P‐gp, encoded by ABCB1) and breast cancer resistance protein (BCRP,ABCG2) protect the foetus from exposure to maternally derived glucocorticoids, toxins and xenobiotics. During pregnancy, maternal glucocorticoid levels can be elevated by stress or exogenous administration. We hypothesized that glucocorticoids modulate the expression of ABCB1/P‐gp and ABCG2/BCRP in the first trimester human placenta. Our objective was to examine whether dexamethasone (DEX) or cortisol modulate first trimester placental expression of multidrug transporters and determine whether cytotrophoblasts or the syncytiotrophoblast are/is responsible for mediating these effects. Three models were examined: (i) an ex‐vivo model of placental villous explants (7‐10 weeks), (ii) a model of isolated first trimester syncytiotrophoblast and cytotrophoblast cells and (iii) the BeWo immortalized trophoblast cell line model. These cells/tissues were treated with DEX or cortisol for 24 hour to 72 hour. In first trimester placental explants, DEX (48 hour) increased ABCB1 (P < .001) and ABCG2 (P < .05) mRNA levels, whereas cortisol (48 hour) only increased ABCB1 mRNA levels (P < .01). Dexamethasone (P < .05) and cortisol (P < .01) increased BCRP but did not affect P‐gp protein levels. Breast cancer resistance protein expression was primarily confined to syncytiotrophoblasts. BeWo cells, when syncytialized with forskolin, increased expression of BCRP protein, and this was further augmented by DEX (P < .05). Our data suggest that the protective barrier provided by BCRP increases as cytotrophoblasts fuse to form the syncytiotrophoblast. Increase in glucocorticoid levels during the first trimester may reduce embryo/foetal exposure to clinically relevant BCRP substrates, because of an increase in placental BCRP.

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.

Generating diversity in human glucocorticoid signaling through a racially diverse polymorphism in the beta isoform of the glucocorticoid receptor

Alternative splicing of the human glucocorticoid receptor gene generates two isoforms, hGRα and hGRβ. hGRβ functions as a dominant-negative regulator of hGRα activity and but also has inherent transcriptional activity, collectively altering glucocorticoid sensitivity. Single-nucleotide polymorphisms in the 3' UTR of hGRβ have been associated with altered receptor protein expression, glucocorticoid sensitivity, and disease risk. Characterization of the hGRβ G3134T polymorphism has been limited to a relatively small, homogenous population. The objective of this study was to determine the prevalence of hGRβ G3134T in a diverse population and assess the association of hGRβ G3134T in this population with physiological outcomes. In a prospective cohort study, 3730 genetically diverse participants were genotyped for hGRβ G3134T and four common GR polymorphisms. A subset of these participants was evaluated for clinical and biochemical measurements. Immortalized human osteosarcoma cells (U-2 OS), stably transfected with wild-type or G3134T hGRβ, were evaluated for receptor expression, stability, and genome-wide gene expression. Glucocorticoid-mediated gene expression profiles were investigated in primary macrophages isolated from participants. In a racially diverse population, the minor allele frequency was 74% (50.7% heterozygous carriers and 23.3% homozygous minor allele), with a higher prevalence in Caucasian non-Hispanic participants. After adjusting for confounding variable, carriers of hGRβ G3134T were more likely to self-report allergies, have higher serum cortisol levels, and reduced cortisol suppression in response to low-dose dexamethasone. The presence of hGRβ G3134T in U-2 OS cells increased hGR mRNA stability and protein expression. Microarray analysis revealed that the presence of the hGRβ G3134T polymorphism uniquely altered gene expression profiles in U-2 OS cells and primary macrophages. hGRβ G3134T is significantly present in the study population and associated with race, self-reported disease, and serum levels of glucocorticoids. Underlying these health differences may be changes in gene expression driven by altered receptor stability.

Elevated utero/placental GR/NR3C1 is not required for the induction of parturition in the dog

The endocrine mechanisms that lead to initiation of parturition in dogs are still not fully understood. The prepartum luteolysis is associated with increased prostaglandin (PG) F2α secretion; however, there is no pregnancy- or parturition-related increase in estrogens. Moreover, unlike in other mammalian species, in the dog, increased peripartum levels of cortisol measured sporadically in maternal peripheral blood are not mandatory for normal parturition. Nevertheless, auto/paracrine effects of cortisol at the placental feto-maternal level cannot be excluded. Therefore, the aim of this study was to investigate the expression and localization of glucocorticoid receptor (GR/NR3C1) in canine utero/placental (Ut/Pl) units and uterine interplacental sites at selected time points during pregnancy (pre-implantation, post-implantation and mid-gestation), and at normal and antigestagen-induced parturition. The Ut/Pl expression of GR/NR3C1 did not change significantly from pre-implantation until mid-gestation; however, it was strongly induced during the prepartum luteolysis. Within the interplacental samples, expression of GR/NR3C1-mRNA was greater post-implantation than pre-implantation and did not change afterward, i.e. toward mid-gestation. Compartmentalization studies within the Ut/Pl units, involving placenta, endometrium and myometrium separately, performed at the prepartum luteolysis revealed the highest GR/NR3C1-mRNA levels in placenta compared with endometrium and myometrium. Interestingly, in antigestagen-treated mid-pregnancy dogs, Ut/Pl and interplacental GR/NR3C1-mRNA expression remained unaffected. At the cellular level, placental GR/NR3C1 was clearly detectable in placenta fetalis, i.e. in trophoblast cells. In conclusion, increased expression of GR/NR3C1 during normal parturition, but not following antigestagen-treatment, suggest that it is not required for initiating the signaling cascade of PG synthesis leading to the induction of parturition in the dog.

The pro-social neurohormone oxytocin reverses the actions of the stress hormone cortisol in human ovarian carcinoma cells in vitro

The journey patients with ovarian cancer travel from non-specific symptoms causing delayed diagnosis through surgery and chemotherapy, culminating in a 5-year survival rate of 43%, must have a profound and detrimental psychological impact on patients. Emerging studies link higher levels of oxytocin (OT) and increased social support, an independent prognostic factor in cancer, with a moderating effect on stress. In contrast, there is a known association of tumour cell proliferation with elevated cortisol (stress hormone) levels. We hypothesise therefore that there is cross-talk between cortisol and oxytocin at a molecular level. Three ovarian cancer cell lines, used as in vitro models, were treated with cortisol at concentrations mimicking physiological stress in vivo in the presence or absence of OT. OT reduced cell proliferation and migration, induced apoptosis and autophagy for all three cell lines, partially reversing the effects of cortisol. Quantitative RT-PCR of tissue taken from ovarian cancer patients revealed that the glucocorticoid receptor (splice variant GR-P) and OT receptor (OTR) were significantly upregulated compared to controls. Tissue microarray revealed that the expression of GRα was lower in the ovarian cancer samples compared to normal tissue. OT is also shown to drive alternative splicing of the GR gene and cortisol-induced OTR expression. OT was able to transactivate GR in the presence of cortisol, thus providing further evidence of cross-talk in vitro. These data provide explanations for why social support might help distressed ovarian cancer patients and help define novel hypotheses regarding potential therapeutic interventions in socially isolated patients.

Hyperglycemia down-regulates cGMP-dependent protein kinase I expression in first trimester cytotrophoblast cells

Diabetes in pregnancy is associated with microvascular complications and a higher incidence of preeclampsia. The regulatory signaling pathways involving nitric oxide, cGMP, and cGMP-dependent protein kinase (PKG) have been shown to be down-regulated under diabetic conditions and contribute to the pathogenesis of vascular complications in diabetes. The present study was undertaken to investigate how high glucose concentrations regulate PKG expression in cytotrophoblast cells (CTBs). Human CTBs (Sw. 71) were treated with 45, 135, 225, 495, or 945 mg/dL glucose for 48 h. Some cells were pretreated with a p38 inhibitor (10 μM SB203580) or 10 μM rosiglitazone. After treatment, the cell lysates were subjected to measure the expression of protein kinase G1α (PKG1α), protein kinase G1β (PKG1β), soluble guanylate cyclase 1α (sGC1α), and soluble guanylate cyclase 1 β (sGC1β) by Western blot. Statistical comparisons were performed using analysis of variance with Duncan's post hoc test. The expressions of PKG1α, PKG1β, sGC1α, and sGC1β were significantly down-regulated (p < 0.05) in CTBs treated with >135 mg/dL glucose compared to basal (45 mg/dL). The hyperglycemia-induced down-regulation of cGMP and cGMP-dependent PKG were attenuated by the SB203580 or rosiglitazone pretreatment. Exposure of CTBs to excess glucose down-regulates cGMP and cGMP-dependent PKG, contributing to the development of vascular complications in diabetic mothers during pregnancy. The attenuation of hyperglycemia-induced down-regulation of PKG proteins by SB203580 or rosiglitazone pretreatment further suggests the involvement of stress signaling mechanisms in this process.

Pro-inflammatory mediators increase levels of the noncoding RNA GAS5 in airway smooth muscle and epithelial cells

The long noncoding RNA (lncRNA) GAS5 has been found to act as a decoy for the glucocorticoid receptor (GR), thus implicating GAS5 as a potential regulator of glucocorticoid sensitivity and resistance. Airway smooth muscle (ASM) cells and airway epithelial cells (AEC) play an important role in the pathogenesis and persistence of asthma and other chronic airways diseases. These airway structural cell types are also important cellular targets of the anti-inflammatory actions of glucocorticoids. In this study, we sought to examine the relevance of GAS5 to glucocorticoid sensitivity and resistance in ASM and AEC. We provide the first evidence that pro-inflammatory mediators up-regulate GAS5 levels in both airway epithelial and smooth muscle cells, and that decreasing GAS5 levels can enhance glucocorticoid action in AEC.