Maternal anxiety and depression in pregnancy and DNA methylation of the NR3C1 glucocorticoid receptor gene

Differential impact of prenatal PTSD symptoms and preconception trauma exposure on placental NR3C1 and FKBP5 methylation

Perinatal stress is associated with altered placental methylation, which plays a critical role in fetal development and infant outcomes. This proof-of-concept pilot study investigated the impact of lifetime trauma exposure and perinatal PTSD symptoms on epigenetic regulation of placenta glucocorticoid signaling genes (NR3C1 and FKBP5). Lifetime trauma exposure and PTSD symptoms during pregnancy were assessed in a racially/ethnically diverse sample of pregnant women (N = 198). Participants were categorized into three groups: (1) No Trauma (-T); (2) Trauma, No Symptoms (T - S); and (3) Trauma and Symptoms (T + S). Placental tissue was analyzed via bisulfite pyrosequencing for degree of methylation at the NR3C1 promoter and FKBP5 regulatory regions. Analyses of covariance were used to test group differences in percentages of NR3C1 and FKBP5 methylation overall and at each CpG site. We found a significant impact of PTSD symptoms on placental NR3C1 methylation. Compared to the -T group, the T + S group had greater NR3C1 methylation overall and at CpG6, CpG8, CpG9, and CpG13, but lower methylation at CpG5. The T + S group had significantly higher NR3C1 methylation overall and at CpG8 compared to the T - S group. There were no differences between the T - S group and - T group. Additionally, no group differences emerged for FKBP5 methylation. Pregnant trauma survivors with PTSD symptoms exhibited differential patterns of placental NR3C1 methylation compared to trauma survivors without PTSD symptoms and pregnant women unexposed to trauma. Results highlight the critical importance of interventions to address the mental health of pregnant trauma survivors.

Association between academic pressure, NR3C1 gene methylation, and anxiety symptoms among Chinese adolescents: a nested case-control study

BACKGROUND

Academic pressure is a prevalent stressor among Chinese adolescents and is often linked to anxiety symptoms, although the underlying mechanism remains unclear. This study aimed to investigate the association between NR3C1 gene methylation, academic pressure, and anxiety symptoms among Chinese adolescents.

METHODS

This nested-case control study included 150 adolescents (boys: 38.7%; baseline age: 12-17 years) from a school-based longitudinal study of Chinese adolescents. Cases (n = 50) were defined as those with anxiety symptoms at both baseline and follow-up, while controls (n = 100) were randomly selected from those without anxiety symptoms at both timepoints. The cases and controls were 1:2 matched by age. Academic pressure, anxiety symptoms, and potential covariates were measured using a self-report questionnaire. Peripheral whole blood samples were collected from each participant for the detection of cortisol level (i.e., morning serum cortisol level) and DNA methylation. The methylation analysis included a total of 27 CpG units at the NR3C1 promoter region.

RESULTS

The final adjusted models showed that students with heavy academic pressure at baseline were at a higher risk of anxiety symptoms at follow-up compared to those with mild academic pressure (β estimate: 6.24 [95% CI: 3.48 ~ 9.01]). After adjusting for covariates, the methylation level of one CpG unit (NR3C1-16 CpG10) in NR3C1 differed significantly between cases and controls (F = 6.188, P = 0.014), and the difference remained significant after correction for multiple testing (P < 0.025). The adjusted regression models showed that moderate (β estimate = 0.010 [95% CI: 0.000 ~ 0.020], P = 0.046) and heavy (β estimate = 0.011 [95% CI: 0.001 ~ 0.020], P = 0.030) academic pressure were significantly associated with the methylation level of NR3C1-16 CpG 10. Further mediation analysis demonstrated that the association of academic pressure and anxiety symptoms was significantly mediated by the methylation of NR3C1-16 CpG 10 (β estimate for indirect effect = 0.11 [95% CI: 0.005 ~ 0.32]; indirect/total effect = 8.3%).

CONCLUSION

The present study suggests that NR3C1-16 CpG 10 DNA methylation might be a potential mechanism that partially explains the lasting effects of academic pressure on subsequent anxiety symptoms among adolescents. Further studies with larger sample sizes are recommended to replicate this finding.

Targeted DNA Demethylation: Vectors, Effectors and Perspectives

Aberrant DNA hypermethylation at regulatory cis-elements of particular genes is seen in a plethora of pathological conditions including cardiovascular, neurological, immunological, gastrointestinal and renal diseases, as well as in cancer, diabetes and others. Thus, approaches for experimental and therapeutic DNA demethylation have a great potential to demonstrate mechanistic importance, and even causality of epigenetic alterations, and may open novel avenues to epigenetic cures. However, existing methods based on DNA methyltransferase inhibitors that elicit genome-wide demethylation are not suitable for treatment of diseases with specific epimutations and provide a limited experimental value. Therefore, gene-specific epigenetic editing is a critical approach for epigenetic re-activation of silenced genes. Site-specific demethylation can be achieved by utilizing sequence-dependent DNA-binding molecules such as zinc finger protein array (ZFA), transcription activator-like effector (TALE) and clustered regularly interspaced short palindromic repeat-associated dead Cas9 (CRISPR/dCas9). Synthetic proteins, where these DNA-binding domains are fused with the DNA demethylases such as ten-eleven translocation (Tet) and thymine DNA glycosylase (TDG) enzymes, successfully induced or enhanced transcriptional responsiveness at targeted loci. However, a number of challenges, including the dependence on transgenesis for delivery of the fusion constructs, remain issues to be solved. In this review, we detail current and potential approaches to gene-specific DNA demethylation as a novel epigenetic editing-based therapeutic strategy.

Evaluation of DNA methylation in BDNF, SLC6A4, NR3C1 and FKBP5 before and after treatment with selective serotonin-reuptake inhibitor in major depressive disorder

Aim: To identify the DNA methylation status of related genes in major depressive disorder following selective serotonin-reuptake inhibitor treatment. Materials & methods: 45 patients with major depressive disorder and 45 healthy volunteers were considered experimental and control groups, respectively. High-resolution melting real-time PCR was implemented to evaluate DNA methylation. Results: After 100 days of selective serotonin-reuptake inhibitor treatment, methylation of promoter CpG sites of BDNF, NR3C1, FKBP5 and SLC6A4 was significantly reduced. Compared with before treatment, patients' Hamilton Depression Rating Scale scores were significantly reduced after selective serotonin-reuptake inhibitor treatment (p ≤ 0.0001). Conclusion: Based on the proven effect of antidepressants on DNA methylation and gene expression, these medications can improve the treatment process and reduce depression scores after treatment.

Maternal and infant NR3C1 and SLC6A4 epigenetic signatures of the COVID-19 pandemic lockdown: when timing matters

Stress exposure during pregnancy is critically linked with maternal mental health and child development. The effects might involve altered patterns of DNA methylation in specific stress-related genes (i.e., glucocorticoid receptor gene, NR3C1, and serotonin transporter gene, SLC6A4) and might be moderated by the gestational timing of stress exposure. In this study, we report on NR3C1 and SLC6A4 methylation status in Italian mothers and infants who were exposed to the COVID-19 pandemic lockdown during different trimesters of pregnancy. From May 2020 to February 2021, 283 mother-infant dyads were enrolled at delivery. Within 24 h from delivery, buccal cells were collected to assess NR3C1 (44 CpG sites) and SLC6A4 (13 CpG sites) methylation status. Principal component (PC) analyses were used to reduce methylation data dimension to one PC per maternal and infant gene methylation. Mother-infant dyads were split into three groups based on the pregnancy trimester (first, second, third), during which they were exposed to the COVID-19 lockdown. Mothers and infants who were exposed to the lockdown during the first trimester of pregnancy had lower NR3C1 and SLC6A4 methylation when compared to counterparts exposed during the second or third trimesters. The effect remained significant after controlling for confounders. Women who were pregnant during the pandemic and their infants might present altered epigenetic biomarkers of stress-related genes. As these epigenetic marks have been previously linked with a heightened risk of maternal psychiatric problems and less-than-optimal child development, mothers and infants should be adequately monitored for psychological health during and after the pandemic.

The association between peritraumatic distress, perceived stress, depression in pregnancy, and NR3C1 DNA methylation among Chinese pregnant women who experienced COVID-19 lockdown

Prenatal stress can affect pregnant women in an epigenetic way during the critical period of conception of their offspring. The study aims to investigate the relationship between peritraumatic distress, prenatal perceived stress, depression, and glucocorticoid receptor (NR3C1) DNA methylation among pregnant women who experienced COVID-19 lockdown in China. Study data were collected from 30 pregnant women in Wuhan and Huanggang, China. The Peritraumatic Distress Inventory was used to measure peritraumatic distress, the Edinburgh Postnatal Depression Scale was used to measure depressive symptoms, and the Perceived Stress Scale was used to measure perceived stress. DNA methylation in the exon 1F promoter region of NR3C1 gene from the venous blood mononuclear cell genome was characterized by bisulfite sequencing. Correlation and linear regression were used for data analysis. The mean level of peritraumatic distress, perceived stress, and depression was 6.30 (SD = 5.09), 6.50 (SD = 5.41), and 6.60 (SD = 4.85), respectively, with 23.33% of pregnant women being depressed. The mean NR3C1 methylation was 0.65 (SD = 0.22). Prenatal depression was positively correlated with the degree of methylation in venous blood from the mother (r = 0.59, p = 0.001), and depression predicted methylation of NR3C1 gene at the CpG 8 site (β = 0.05, p = 0.03). No association was found between peritraumatic distress as well as perceived stress and methylation of NR3C1. NR3C1 gene was susceptible to epigenetic modification of DNA methylation in the context of prenatal stress, and maternal depression was associated with increased NR3C1 methylation among women who experienced COVID-19 lockdown.

Hypothalamic NR3C1 DNA methylation in rats exposed to prenatal stress

BACKGROUND

Human and animal studies have indicated that maternal prenatal stress (PS) has molecular and behavioral effects during pregnancy and early life. The present study aimed to evaluate the epigenetic changes of the NR3C1 gene involved in the HPA axis in the hypothalamic tissues of rats exposed to PS induced by chronic unpredictable mild stress (CUMS). Behavioral and molecular effects of these changes on the next generation were also assessed.

METHODS AND RESULTS

CUMS protocol was used to generate stress in pregnant Wistar rats. To determine the effects of stress on anhedonia and movement, sucrose preference test, forced swimming test, and open field test were performed. Following these behavioral experiments, bisulfite sequencing PCR for DNA methylation levels of the NR3C1 gene, RT-qPCR for mRNA levels, and Western blot techniques for protein analysis were used in the hypothalamic tissue of sacrificed rats. Depression-like behaviors were evident in the behavioral tests of stress-exposed mothers and pups. In PS-exposed pups, hypothalamic NR3C1 promoter methylation was higher, and NR3C1 mRNA levels and NR3C1 protein levels were lower compared with controls, regardless of sex.

CONCLUSION

Our results confirm the relationship between PS and epigenetic changes of HPA axis-related genes and show that NR3C1 gene methylation status in pups is sensitive to PS during pregnancy. Environmental maternal stress may have transgenerational effects that are potentially associated with adverse outcomes in the pups.

Gender-specific associations of pregnancy-related anxiety with placental epigenetic patterning of glucocorticoid response genes and preschooler's emotional symptoms and hyperactivity

BACKGROUD

We have recently reported that maternal prenatal pregnancy-related anxiety predicts preschoolers' emotional and behavioral development in a gender-dependent manner. This study aims to test for this gender-specific effect in a different cohort and investigate whether the gender difference was specific to placental methylation of genes regulating glucocorticoids.

METHODS

A total of 2405 mother-child pairs from the Ma'anshan Birth Cohort Study were included in present study. The maternal pregnancy-related anxiety symptoms were evaluated with the Pregnancy-Related Anxiety Questionnaire in the third trimester of pregnancy. Child neurobehavior was assessed with the Strengths and Difficulties Questionnaire at 4 years old. Placental methylation of FKBP5, NR3C1 and HSD11B2 genes was quantified using the MethylTarget approach in 439 pregnant women. After exploratory factor analysis, the associations between methylation factor scores and pregnancy-related anxiety and child neurobehavior were examined using logistic regression analysis.

RESULTS

After controlling for confounding factors, pregnancy-related anxiety in the third trimester of pregnancy increased the risk of hyperactivity only in boys and emotional symptoms only in girls. Decreased scores of the factor characterized by FKBP5 methylation were associated with maternal pregnancy-related anxiety only in boys. Furthermore, increased scores of the factors characterized by NR3C1 and HSD11B2 methylation were associated with hyperactivity (NR3C1: adjusted OR = 1.80, 95%CI = 1.15-2.83) and emotional symptoms (HSD11B2: adjusted OR = 0.53, 95%CI = 0.29-0.97; NR3C1: adjusted OR = 1.64, 95%CI = 1.03-2.59) only in boys. However, the scores of the factor characterized by FKBP5, NR3C1 and HSD11B2 did not mediate the relationship between maternal pregnancy-related anxiety and preschoolers' emotional symptoms and hyperactivity.

CONCLUSIONS

Our results suggested that pregnancy-related anxiety in the third trimester of pregnancy predicted preschoolers' emotional symptoms and hyperactivity in a gender-dependent manner. Although we did not find the mediation role of the placental methylation of genes regulating glucocorticoids, we found it was associated with both maternal pregnancy-related anxiety and preschoolers' emotional symptoms and hyperactivity in a gender-dependent manner.

The clinical significance of the glucocorticoid receptors: Genetics and epigenetics

The impacts of glucocorticoids (GCs) are mainly mediated by a nuclear receptor (GR) existing in almost every tissue. The GR regulates a wide range of physiological functions, including inflammation, cell metabolism, and differentiation playing a major role in cellular responses to GCs and stress. Therefore, the dysregulation or disruption of GR can cause deficiencies in the adaptation to stress and the preservation of homeostasis. The number of GR polymorphisms associated with different diseases has been mounting per year. Tackling these clinical complications obliges a comprehensive understanding of the molecular network action of GCs at the level of the GR structure and its signaling pathways. Beyond genetic variation in the GR gene, epigenetic changes can enhance our understanding of causal factors involved in the development of diseases and identifying biomarkers. In this review, we highlight the relationships of GC receptor gene polymorphisms and epigenetics with different diseases.