Glucocorticoid receptor DNA methylation, childhood maltreatment and major depression

The significance of DNA methylation of the NR3C1 gene encoding the glucocorticoid receptor for developing resilience in individuals exposed to early life stress

PURPOSE

To analyze and interpret why some individuals are resilient to ELS while others are susceptible, resulting in psychiatric outcome later in life, with a focus on the role of DNAm of the NR3C1 gene as a mediating mechanism between ELS and the risk of psychiatric outcomes. We hypothesized that a high level of mental resilience to ELS, expressed as lower incidence of psychiatric outcomes, was associated with attenuated NR3C1 DNAm levels.

MATERIALS AND METHODS

The first authors conducted a systematic search on PubMed to identify primary research studies. Abstract were screened and full-text were reviewed to assess the eligibility for inclusion. Consensus on assessment was reached after discussion of eligibility criteria. Studies were sorted based on whether they investigated the association between ELS and NR3C1 DNAm in 1) individuals exposed compared to unexposed to ELS both without a psychiatric outcome or in 2) individuals exposed to ELS with a psychiatric outcome compared to exposed individuals without a psychiatric outcome.

RESULTS AND CONCLUSION

Seven studies met the eligibility criteria. The results were inconsistent; two studies supported our hypothesis, two studies indicated that increased NR3C1 DNAm mediated resilience to ELS, and three studies found no association.

Endophenotype 2.0: updated definitions and criteria for endophenotypes of psychiatric disorders, incorporating new technologies and findings

Recent genetic studies have linked numerous loci to psychiatric disorders. However, the biological pathways that connect these genetic associations to psychiatric disorders' specific pathophysiological processes are largely unclear. Endophenotypes, first defined over five decades ago, are heritable traits, independent of disease state that are associated with a disease, encompassing a broad range of neurophysiological, biochemical, endocrinological, neuroanatomical, cognitive, and neuropsychological characteristics. Considering the advancements in genetics and genomics over recent decades, we propose a revised definition of endophenotypes as 'genetically influenced phenotypes linked to disease or treatment characteristics and their related events.' We also updated endophenotype criteria to include (1) reliable measurement, (2) association with the disease or its related events, and (3) genetic mediation. 'Genetic mediation' is introduced to differentiate between causality and pleiotropic effects and allows non-linear relationships. Furthermore, this updated Endophenotype 2.0 framework expands to encompass genetically regulated responses to disease-related factors, including environmental risks, illness progression, treatment responses, and resilience phenotypes, which may be state-dependent. This broadened definition paves the way for developing new endophenotypes crucial for genetic analyses in psychiatric disorders. Integrating genetics, genomics, and diverse endophenotypes into multi-dimensional mechanistic models is vital for advancing our understanding of psychiatric disorders. Crucially, elucidating the biological underpinnings of endophenotypes will enhance our grasp of psychiatric genetics, thereby improving disease risk prediction and treatment approaches.

Mapping the epigenomic landscape of post-traumatic stress disorder in human cortical neurons

The study conducted a comprehensive genome-wide analysis of differential 5mC and 5hmC modifications at both CpG and non-CpG sites in postmortem orbitofrontal neurons from 25 PTSD cases and 13 healthy controls. It was observed that PTSD patients exhibit a greater number of differential 5hmC sites compared to 5mC sites. Specifically, individuals with PTSD tend to show hyper-5mC/5hmC at CpG sites, particularly within CpG islands and promoter regions, and hypo-5mC/5hmC at non-CpG sites, especially within intragenic regions. Functional enrichment analysis indicated distinct yet interconnected roles for 5mC and 5hmC in PTSD. The 5mC marks primarily regulate cell-cell adhesion processes, whereas 5hmC marks are involved in embryonic morphogenesis and cell fate commitment. By integrating published PTSD findings from central and peripheral tissues through multi-omics approaches, several biological mechanisms were prioritized, including developmental processes, HPA axis regulation, and immune responses. Based on the consistent enrichment in developmental processes, we hypothesize that if epigenetic changes occur during early developmental stages, they may increase the risk of developing PTSD following trauma exposure. Conversely, if these epigenetic changes occur in adulthood, they may influence neuronal apoptosis and survival mechanisms.

Childhood trauma and hair cortisol response over the year following onset of a chronic life event stressor

OBJECTIVE

Childhood trauma may contribute to poor lifelong health in part through programming of the HPA-axis response to future life stressors. To date, empirical evidence shows an association of childhood trauma with dysregulation of the HPA-axis and blunted cortisol reactivity to acute stressors. Here, we conduct an initial examination of childhood trauma as a moderator of changes over time in perceived stress levels and HPA-axis response to a major chronic stressor in adulthood.

METHODS

Participants were 83 maternal caregivers of children newly diagnosed with cancer who completed the Childhood Trauma Questionnaire (CTQ), and who, over the year following their child's cancer diagnosis, had hair samples collected up to 7 times for the assessment of cortisol and completed monthly measures of perceived stress.

RESULTS

CTQ scores were in the expected range for a community sample and associated with changes in perceived stress and cortisol concentration over time (γ =.003, p =.002; γ = -.0004, p =.008, respectively) independently of age, education, treatment intensity and randomization to stress management intervention. Maternal caregivers who endorsed lower childhood trauma showed a steeper decline in perceived stress and a larger increase in cortisol levels across the year than caregivers who recalled more childhood trauma.

CONCLUSIONS

Findings extend animal models and studies that examine cortisol reactivity to acute stressors and suggest that childhood trauma may program a phenotype that is more psychologically reactive but shows a blunted HPA-axis response to chronic stress. While adaptive in the short-term, this early life programming may incur long-term costs for health. Further work is warranted to examine this possibility.

Epigenetic and Coping Mechanisms of Stress in Affective Disorders: A Scoping Review

This review aims to explore the intricate relationship among epigenetic mechanisms, stress, and affective disorders, focusing on how early life experiences and coping mechanisms contribute to susceptibility to mood disorders. Epigenetic factors play a crucial role in regulating gene expression without altering the DNA (deoxyribonucleic acid) sequence, and recent research has revealed associations between epigenetic changes and maladaptive responses to stress or psychiatric disorders. A scoping review of 33 studies employing the PRISMA-S (Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Statement) guidelines investigates the role of stress-induced epigenetic mechanisms and coping strategies in affective disorder occurrence, development, and progression. The analysis encompasses various stress factors, including childhood trauma, work-related stress, and dietary deficiencies, alongside epigenetic changes, such as DNA methylation and altered gene expression. Findings indicate that specific stress-related genes frequently exhibit epigenetic changes associated with affective disorders. Moreover, the review examines coping mechanisms in patients with bipolar disorder and major depressive disorder, revealing mixed associations between coping strategies and symptom severity. While active coping is correlated with better outcomes, emotion-focused coping may exacerbate depressive or manic episodes. Overall, this review underscores the complex interplay among genetic predisposition, environmental stressors, coping mechanisms, and affective disorders. Understanding these interactions is essential for developing targeted interventions and personalized treatment strategies for individuals with mood disorders. However, further research is needed to elucidate specific genomic loci involved in affective disorders and the clinical implications of coping strategies in therapeutic settings.

An industrialized diet as a determinant of methylation in the 1F region of the NR3C1 gene promoter

Background

Dietary composition can modify gene expression, favoring the development of chronic diseases via epigenetic mechanisms.

Objective

Our study aimed to investigate the relationship between dietary patterns and NR3C1 gene methylation in users of the Brazilian Public Unified Health System (SUS).

Methods

We recruited 250 adult volunteers and evaluated their socioeconomic status, psychosocial characteristics, lifestyle, and anthropometrics. Peripheral blood was collected and evaluated for cortisol levels, glycemia, lipid profile, and insulin resistance; methylation of CpGs 40-47 of the 1F region of the NR3C1 gene was also measured. Factors associated with degree of methylation were evaluated using generalized linear models (p < 0.05). Lifestyle variables and health variables were included as confounding factors.

Results

The findings of our cross-sectional study indicated an association between NR3C1 DNA methylation and intake of processed foods. We also observed relevant associations of average NR3C1 DNA across the segment analyzed, methylation in component 1 (40-43), and methylation in component 2 (44-47) with a pattern of consumption of industrialized products in relation to BMI, serum cortisol levels, and lipid profile. These results may indicate a relationship between methylation and metabolic changes related to the stress response.

Conclusion

These findings suggest an association of methylation and metabolic alterations with stress response. In addition, the present study highlights the significant role of diet quality as a stress-inducing factor that influences NR3C1 methylation. This relationship is further linked to changes in psychosocial factors, lifestyle choices, and cardiometabolic variables, including glucose levels, insulin resistance, and hyperlipidemia.

Research trend of epigenetics and depression: adolescents' research needs to strengthen

Objective

With its high prevalence, depression's pathogenesis remains unclear. Recent attention has turned to the interplay between depression and epigenetic modifications. However, quantitative bibliometric analyses are lacking. This study aims to visually analyze depression epigenetics trends, utilizing bibliometric tools, while comprehensively reviewing its epigenetic mechanisms.

Methods

Utilizing the Web of Science core dataset, we collected depression and epigenetics-related studies. Employing VOSViewer software, we visualized data on authors, countries, journals, and keywords. A ranking table highlighted field leaders.

Results

Analysis encompassed 3,469 depression epigenetics studies published from January 2002 to June 2023. Key findings include: (1) Gradual publication growth, peaking in 2021; (2) The United States and its research institutions leading contributions; (3) Need for enhanced collaborations, spanning international and interdisciplinary efforts; (4) Keyword clustering revealed five main themes-early-life stress, microRNA, genetics, DNA methylation, and histone acetylation-highlighting research hotspots; (5) Limited focus on adolescent depression epigenetics, warranting increased attention.

Conclusion

Taken together, this study revealed trends and hotspots in depression epigenetics research, underscoring global collaboration, interdisciplinary fusion, and multi-omics data's importance. It discussed in detail the potential of epigenetic mechanisms in depression diagnosis and treatment, advocating increased focus on adolescent research in this field. Insights aid researchers in shaping their investigative paths toward understanding depression's epigenetic mechanisms and antidepressant interventions.

Does biological age mediate the relationship between childhood adversity and depression? Insights from the Detroit Neighborhood Health Study

The link between childhood adversity and adulthood depression is well-established; however, the underlying mechanisms are still being explored. Recent research suggests biological age may mediate the relationship between childhood adversity and depression in later life. This study examines if biological age mediates the relationship between childhood adversity and depression symptoms using an expanded set of biological age measures in an urban population-based cohort. Data from waves 1-3 of the Detroit Neighborhood Health Study (DNHS) were used in this analysis. Questions about abuse during childhood were coded to form a childhood adversity score similar to the Adverse Childhood Experience measure. Multiple dimensions of biological age, defined as latent variables, were considered, including systemic biological age (GrimAge, PhenoAge), epigenetic age (Horvath, SkinBlood), and immune age (cytomegalovirus, herpes simplex virus type 1, C-reactive protein, interleukin-6). Depression symptoms, modeled as a latent variable, were captured through the Patient Health Questionnaire-9 (PHQ-9). Models were adjusted for age, gender, race, parent education, and past depressive symptoms. Total and direct effects of childhood adversity on depression symptoms and indirect effects mediated by biological age were estimated. For total and direct effects, we observed a dose-dependent relationship between cumulative childhood adversity and depression symptoms, with emotional abuse being particularly influential. However, contrary to prior studies, in this sample, we found few direct effects of childhood adversity on biological age or biological age on depression symptoms and no evidence of mediation through the measures of biological age considered in this study. Further research is needed to understand how childhood maltreatment experiences are embodied to influence health and wellness.

The association of epigenetic age acceleration and depressive and anxiety symptom severity among children recently exposed to substantiated maltreatment

Child maltreatment is a major risk factor for both depressive and anxiety disorders. However, many children exposed to maltreatment never meet diagnostic threshold for either disorder while experiencing only transitory symptoms post-exposure. Recent research suggests DNA methylation adds predictive value in explaining variation in the onset and course of multiple psychiatric disorders following exposure to child maltreatment. Epigenetic age acceleration (EAA), the biological aging of cells not attributable to chronological aging, is a stress-sensitive biomarker capturing genome-wide variation in DNA methylation with the potential to identify children who have been maltreated at greatest risk for depressive and anxiety disorders. The current study examined two EAA clocks appropriate for the pediatric population, the Horvath and Pediatric Buccal Epigenetic (PedBE) clocks, and their associations with depressive and anxiety symptom severity following child maltreatment. Children (N = 71) 8-15 years of age, all of whom were exposed to substantiated child maltreatment in the 12 months prior to study entry, were enrolled. Risk modeling adjusting for several confounders revealed that EAA estimated via the Horvath clock was significantly associated with more severe depressive and anxiety symptoms. The PedBE clock was not associated with either depressive or anxiety symptom severity. Sensitivity analyses demonstrated that EAA via the Horvath clock robustly predicted depressive and anxiety symptom severity across multiple modeling scenarios. Our findings advance existing research suggesting EAA, as estimated with the Horvath clock, may be a promising biomarker for identifying children at greatest risk for more severe depressive and anxiety symptoms following maltreatment.

Epigenetic regulation in major depression and other stress-related disorders: molecular mechanisms, clinical relevance and therapeutic potential

Major depressive disorder (MDD) is a chronic, generally episodic and debilitating disease that affects an estimated 300 million people worldwide, but its pathogenesis is poorly understood. The heritability estimate of MDD is 30-40%, suggesting that genetics alone do not account for most of the risk of major depression. Another factor known to associate with MDD involves environmental stressors such as childhood adversity and recent life stress. Recent studies have emerged to show that the biological impact of environmental factors in MDD and other stress-related disorders is mediated by a variety of epigenetic modifications. These epigenetic modification alterations contribute to abnormal neuroendocrine responses, neuroplasticity impairment, neurotransmission and neuroglia dysfunction, which are involved in the pathophysiology of MDD. Furthermore, epigenetic marks have been associated with the diagnosis and treatment of MDD. The evaluation of epigenetic modifications holds promise for further understanding of the heterogeneous etiology and complex phenotypes of MDD, and may identify new therapeutic targets. Here, we review preclinical and clinical epigenetic findings, including DNA methylation, histone modification, noncoding RNA, RNA modification, and chromatin remodeling factor in MDD. In addition, we elaborate on the contribution of these epigenetic mechanisms to the pathological trait variability in depression and discuss how such mechanisms can be exploited for therapeutic purposes.

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.

The associations between DNA methylation and depression: A systematic review and meta-analysis

BACKGROUND

Growing evidence suggests that epigenetic modification is vital in biological processes of depression. Findings from studies exploring the associations between DNA methylation and depression have been inconsistent.

METHODS

A systematical search of EMBASE, PubMed, Web of Science, and PsycINFO databases was conducted to include studies focusing on the associations between DNA methylation and depression (up to November 1st 2021) according to PRISMA guidelines with registration in PROSPERO (CRD42021288664).

RESULTS

A total of 47 studies met inclusion criteria and 31 studies were included in the meta-analysis. This meta-analysis found that genes hypermethylation, including BDNF (OR: 1.15, 95%CI: 1.01-1.32, I² = 90 %), and NR3C1 (OR: 1.43, 95%CI: 1.09-1.87, I² = 88 %) was associated with increased risk of depression. Significant association of SLC6A4 hypermethylation with depression was only found in the subgroup of using original data (OR: 1.09, 95%CI: 1.01-1.19, I² = 52 %). BDNF hypermethylation could increase the risk of depression only in the Asian population (OR: 1.18, 95%CI: 1.01-1.40, I² = 91 %), and significant associations of NR3C1 hypermethylation with depression were found in the group for depressive symptoms (OR: 1.34, 95%CI: 1.08-1.67, I² = 85 %), but not for depressive disorder (OR: 1.89, 95%CI: 0.54-6.55, I² = 94 %).

LIMITATIONS

More studies are needed to explore the factors that might influence the estimates owing to the contextual heterogeneity of the pooling of included studies.

CONCLUSIONS

It is noted that DNA hypermethylation, namely BDNF and NR3C1, is associated with increased risk of depression. The findings in this study could provide some material evidence for preventing and diagnosing of depression.

DNA methylation in regulatory elements of the FKBP5 and NR3C1 gene in mother-child binomials with depression

BACKGROUND

The FKBP5 and NR3C1 genes play an important role in stress response, thus impacting mental health. Stress factor exposure in early life, such as maternal depression, may contribute to epigenetic modifications in stress response genes, increasing the susceptibility to different psychopathologies. The present study aimed to evaluate the DNA methylation profile in maternal-infant depression in regulatory regions of the FKBP5 gene and the alternative promoter of the NR3C1 gene.

METHODS

We evaluated 60 mother-infant pairs. The levels of DNA methylation were analyzed by the MSRED-qPCR technique.

RESULTS

We observed an increased DNA methylation profile in the NR3C1 gene promoter in children with depression and children exposed to maternal depression (p < 0.05). In addition, we observed a correlation of DNA methylation between mothers and offspring exposed to maternal depression. This correlation shows a possible intergenerational effect of maternal MDD exposure on the offspring. For FKBP5, we found a decrease in DNA methylation at intron 7 in children exposed to maternal MDD during pregnancy and a correlation of DNA methylation between mothers and children exposed to maternal MDD (p < 0.05).

LIMITATIONS

Although the individuals of this study are a rare group, the sample size of the study was small, and we evaluated the DNA methylation of only one CpG site for each region.

CONCLUSION

These results indicate changes in DNA methylation levels in regulatory regions of FKBP5 and NR3C1 in the mother-child MDD context and represent a potential target of studies to understand the depression etiology and how it occurs between generations.

Association between child maltreatment and depressive symptoms in emerging adulthood: The mediating and moderating roles of DNA methylation

Prospective studies suggest that child maltreatment substantially increases the risk for depression in adulthood. However, the mechanisms underlying this association require further elucidation. In recent years, DNA methylation has emerged as a potential mechanism by which maltreatment experiences (a) could partly explain the emergence or aggravation of depressive symptoms (i.e., mediation) and/or (b) could increase (or decrease) the risk for depressive symptoms (i.e., moderation). The present study tested whether the methylation levels of nine candidate genes mediated and/or moderated the association between maltreatment experiences in childhood and depressive symptoms in emerging adulthood. The sample comprised 156 men aged between 18 and 35 years. Maltreatment experiences and depressive symptoms were assessed retrospectively using self-reported questionnaires. Methylation levels of nine candidate genes (COMT, FKBP5, IL6, IL10, MAOA, NR3C1, OXTR, SLC6A3 and SLC6A4), previously reported to be sensitive to early-life stress, were quantified from saliva samples. Maltreatment experiences in childhood were significantly associated with depressive symptoms in emerging adulthood. Both maltreatment experiences and depressive symptoms were associated with the methylation levels of two genomic sites, which cumulatively, but not individually, explained 16% of the association between maltreatment experiences in childhood and depressive symptoms in emerging adulthood. Moreover, maltreatment experiences in childhood interacted with the methylation levels of fourteen genomic sites, which cumulatively, but not individually, modulated the level of depressive symptoms in young male adults who were maltreated as children. However, none of these effects survived multiple testing correction. These findings bring attention to the cumulative effects of DNA methylation measured in several candidate genes on the risk of reporting depressive symptoms following maltreatment experiences in childhood. Nonetheless, future studies need to clarify the robustness of these putative cumulative effects in larger samples and longitudinal cohorts.

Cross-Species Convergence of Brain Transcriptomic and Epigenomic Findings in Posttraumatic Stress Disorder: A Systematic Review

Introduction

Posttraumatic stress disorder (PTSD) is a complex multifactorial disorder influenced by the interaction of genetic and environmental factors. Analyses of epigenomic and transcriptomic modifications may help to dissect the biological factors underlying the gene-environment interplay in PTSD. To date, most human PTSD epigenetics studies have used peripheral tissue, and these findings have complex and poorly understood relationships to brain alterations. Studies examining brain tissue may help characterize the brain-specific transcriptomic and epigenomic profiles of PTSD. In this review, we compiled and integrated brain-specific molecular findings of PTSD from humans and animals.

Methods

A systematic literature search according to the PRISMA criteria was performed to identify transcriptomic and epigenomic studies of PTSD, focusing on brain tissue from human postmortem samples or animal-stress paradigms.

Results

Gene- and pathway-level convergence analyses revealed PTSD-dysregulated genes and biological pathways across brain regions and species. A total of 243 genes converged across species, with 17 of them significantly enriched for PTSD. Chemical synaptic transmission and signaling by G-protein-coupled receptors were consistently enriched across omics and species.

Discussion

Our findings point out dysregulated genes highly replicated across PTSD studies in humans and animal models and suggest a potential role for the corticotropin-releasing hormone/orexin pathway in PTSD's pathophysiology. Further, we highlight current knowledge gaps and limitations and recommend future directions to address them.

Lifestyle and NR3C1 exon 1F gene methylation is associated with changes in glucose levels and insulin resistance

AIMS

the present study aimed to investigate how glucose and insulin levels may be associated with changes in NR3C1 gene methylation levels in adults.

MAIN METHODS

375 volunteers users of the Brazilian Public Unified Health System (SUS) were recruited to assess socioeconomic status, lifestyle, anthropometric data, blood glucose and serum cortisol levels, insulin resistance, and NR3C1 gene methylation assessment. Factors associated with glucose levels and insulin resistance were investigated using multivariate analysis GLzM at 5 % significance (p < 0.05).

KEY FINDINGS

our results verified that glucose levels and insulin resistance were directly related to NR3C1 gene methylation and age, while not being overweight and obese and no tobacco consumption were indirectly related to glucose levels and insulin resistance.

SIGNIFICANCE

habits and lifestyle may influence NR3C1 gene regulation, revealing the complexity of environmental impacts on NR3C1 methylation. Furthermore, associated risk factors must be taken into account in epigenetic studies as they directly interfere with blood glucose levels and insulin resistance.

Can epigenetics shine a light on the biological pathways underlying major mental disorders?

A significant proportion of the global burden of disease can be attributed to mental illness. Despite important advances in identifying risk factors for mental health conditions, the biological processing underlying causal pathways to disease onset remain poorly understood. This represents a limitation to implement effective prevention and the development of novel pharmacological treatments. Epigenetic mechanisms have emerged as mediators of environmental and genetic risk factors which might play a role in disease onset, including childhood adversity (CA) and cannabis use (CU). Particularly, human research exploring DNA methylation has provided new and promising insights into the role of biological pathways implicated in the aetio-pathogenesis of psychiatric conditions, including: monoaminergic (Serotonin and Dopamine), GABAergic, glutamatergic, neurogenesis, inflammatory and immune response and oxidative stress. While these epigenetic changes have been often studied as disease-specific, similarly to the investigation of environmental risk factors, they are often transdiagnostic. Therefore, we aim to review the existing literature on DNA methylation from human studies of psychiatric diseases (i) to identify epigenetic modifications mapping onto biological pathways either transdiagnostically or specifically related to psychiatric diseases such as Eating Disorders, Post-traumatic Stress Disorder, Bipolar and Psychotic Disorder, Depression, Autism Spectrum Disorder and Anxiety Disorder, and (ii) to investigate a convergence between some of these epigenetic modifications and the exposure to known risk factors for psychiatric disorders such as CA and CU, as well as to other epigenetic confounders in psychiatry research.

DNA methylation of Nuclear Factor of Activated T Cells 1 mediates the prospective relation between exposure to different traumatic event types and post-traumatic stress disorder

The mechanisms through which exposure to differing trauma types become biologically embedded to shape the risk for post-traumatic stress disorder (PTSD) is unclear. DNA methylation (5-mC), particularly in stress-relevant genes, may play a role in this relationship. Here, we conducted path analysis using generalized structural equation modeling to investigate whether blood-derived 5-mC in Nuclear Factor of Activated T Cells 1 (NFATC1) mediates the prospective association between each of five different trauma types ("assaultive violence", "other injury or shocking experience", "learning of trauma to loved one", "sudden, unexpected death of a close friend or relative", and "other") and lifetime PTSD. All five trauma types were significantly associated with reduced methylation at NFATC1 CpG site, cg17057218. Two of the five trauma types were significantly associated with increased methylation at NFATC1 CpG site, cg22324981. Moreover, methylation at cg17057218 significantly mediated 21-32% of the total effect for four of the five trauma types, while methylation at cg22324981 mediated 27-40% of the total effect for two of the five trauma types. These CpG sites were differentially associated with transcription factor binding sites and chromatin state signatures. NFATC1 5-mC may be a potential mechanism in the relationship between some trauma types and prospective risk for PTSD.

Child maltreatment and NR3C1 exon 1F methylation, link with deregulated hypothalamus-pituitary-adrenal axis and psychopathology: A systematic review

BACKGROUND

Epigenetics offers one promising method for assessing the psychobiological response to stressful experiences during childhood. In particular, deoxyribonucleic acid (DNA) methylation has been associated with an altered hypothalamus-pituitary-adrenal (HPA) axis and the onset of mental disorders. Equally, there are promising leads regarding the association between the methylation of the glucocorticoid receptor gene (NR3C1-1_F) and child maltreatment and its link with HPA axis and psychopathology.

OBJECTIVE

The current study aimed to assess the evidence of a link among child maltreatment, NR3C1-1_F methylation, HPA axis deregulation, and symptoms of psychopathology.

METHODS

We followed the Prisma guidelines and identified 11 articles that met our inclusion criteria.

RESULTS

We found that eight studies (72.72%) reported increased NR3C1-1_F methylation associated with child maltreatment, specifically physical abuse, emotional abuse, sexual abuse, neglect, and exposure to intimate partner violence, while three studies (27.27%) found no significant association. Furthermore, a minority of studies (36.36%) provided additional measures of symptoms of psychopathology or cortisol in order to examine the link among NR3C1-1_F methylation, HPA axis deregulation, and psychopathology in a situation of child maltreatment. These results suggest that NR3C1-1_F hypermethylation is positively associated with higher HPA axis activity, i.e. increased production of cortisol, as well as symptoms of psychopathology, including emotional lability-negativity, externalizing behavior symptoms, and depressive symptoms.

CONCLUSION

NR3C1-1_F methylation could be one mechanism that links altered HPA axis activity with the development of psychopathology.

Epigenetics of childhood trauma: Long term sequelae and potential for treatment

Childhood trauma (CT) can have persistent effects on the brain and is one of the major risk factors for neuropsychiatric diseases in adulthood. Recent advances in the field of epigenetics suggest that epigenetic factors such as DNA methylation and histone modifications, as well as regulatory processes involving non-coding RNA are associated with the long-term sequelae of CT. This narrative review summarizes current knowledge on the epigenetic basis of CT and describes studies in animal models and human subjects examining how the epigenome and transcriptome are modified by CT in the brain. It discusses psychological and pharmacological interventions that can counteract epigenetic changes induced by CT and the need to establish longitudinal assessment after CT for developing more effective diagnostics and treatment strategies based on epigenetic targets.

Stress and spirituality in relation to HPA axis gene methylation among US Black women: results from the Black Women's Health Study and the Study on Stress, Spirituality and Health

Background: Few epigenetics studies have been conducted within the Black community to examine the impact of diverse psychosocial stressors and resources for resiliency on the stress pathway (hypothalamus-pituitary-adrenal axis). Methods: Among 1000 participants from the Black Women's Health Study, associations between ten psychosocial stressors and DNA methylation (DNAm) of four stress-related genes (NR3C1, HSDB1, HSD11B2 and FKBP5) were tested. Whether religiosity or spirituality (R/S) significantly modified these stress-DNAm associations was also assessed. Results: Associations were found for several stressors with DNAm of individual CpG loci and average DNAm levels across each gene, but no associations remained significant after false discovery rate (FDR) correction. Several R/S variables appeared to modify the relationship between two stressors and DNAm, but no identified interaction remained significant after FDR correction. Conclusion: There is limited evidence for a strong signal between stress and DNAm of hypothalamus-pituitary-adrenal axis genes in this general population cohort of US Black women.

Food and nutritional insecurity is associated with depressive symptoms mediated by NR3C1 gene promoter 1F methylation

The aim of this study was to investigate socioeconomic stressors predictive of depressive symptoms and possible epigenetic changes in the glucocorticoid receptor - NR3C1-1F - an encoding gene involved in depressive symptoms. A total of 321 adult volunteers from southeastern Brazil were recruited to evaluate depressive symptoms, socio-demographic and economic factors, including food and nutritional security (FNS) or insecurity (FNiS) status, and NR3C1-1F region methylation by pyrosequencing. Depressive symptom determinants were investigated using a Poisson regression model with robust variance. Mann-Whitney tests and structural mediation equation models were used to evaluate the relationship between NR3C1 DNA methylation, FNiS, and depressive symptoms. Multivariate Poisson regression with robust variance adjusted for sex and FNiS and NR3C1-1F region methylation predicted risk factors for depressive symptoms. Mediation analysis revealed that NR3C1-1F region methylation mediated the relationship between FNiS exposure and depressive symptoms as an outcome, and depressive volunteers and FNiS individuals exhibited a significant increase in NR3C1 methylation when compared to healthy individuals and FNS volunteers, respectively. Therefore, we suggest that stress caused by FNiS may lead to depressive symptoms and that NR3C1-1F DNA methylation can act as a mediator of both FNiS and depressive symptoms.

Associations between childhood maltreatment and DNA methylation of the oxytocin receptor gene in immune cells of mother-newborn dyads

The neuropeptide oxytocin (OXT) and its receptor (OXTR) modulate interpersonal relationships, particularly mother-child interactions. DNA methylation (DNAm) changes of the OXTR gene were observed in individuals who experienced Childhood Maltreatment (CM). A modulatory role of single nucleotide polymorphisms (SNP) within OXTR in association with CM on the regulation of OXTR was also postulated. Whether these CM-induced epigenetic alterations are biologically inherited by the offspring remains unknown. We thus investigated possible intergenerational effects of maternal CM exposure on DNAm and OXTR gene expression, additionally accounting for the possible influence of three SNP: rs53576 and rs2254298 (OXTR gene), and rs2740210 (OXT gene). We used the Childhood Trauma Questionnaire to classify mothers into individuals with (CM+) or without CM (CM-). Maternal peripheral immune cells were isolated from venous blood (N = 117) and fetal immune cells from the umbilical cord (N = 113) after parturition. DNA methylation was assessed using MassARRAY. Taqman assays were performed for genotyping and gene expression analyses. Among mothers, CM was not associated with OXTR mean methylation or gene expression. However, four CpG sites showed different methylation levels in CM- compared to CM+. In mothers, the OXTR rs53576 and OXT rs2740210 allelic variations interacted with CM load on the OXTR mean methylation. Maternal and newborns' mean methylation of OXTR were positively associated within CM- dyads, but not in CM+ dyads. We show gene×environment interactions on the epigenetic regulation of the oxytocinergic signaling and show the intergenerational comparability of the OXTR DNAm might be altered in infants of CM+ mothers.

Highlighting Immune System and Stress in Major Depressive Disorder, Parkinson's, and Alzheimer's Diseases, with a Connection with Serotonin

There is recognition that both stress and immune responses are important factors in a variety of neurological disorders. Moreover, there is an important role of several neurotransmitters that connect these factors to several neurological diseases, with a special focus in this paper on serotonin. Accordingly, it is known that imbalances in stressors can promote a variety of neuropsychiatric or neurodegenerative pathologies. Here, we discuss some facts that link major depressive disorder, Alzheimer’s, and Parkinson’s to the stress and immune responses, as well as the connection between these responses and serotonergic signaling. These are important topics of investigation which may lead to new or better treatments, improving the life quality of patients that suffer from these conditions.

The Effects of Early Life Stress on the Brain and Behaviour: Insights From Zebrafish Models

The early life period represents a window of increased vulnerability to stress, during which exposure can lead to long-lasting effects on brain structure and function. This stress-induced developmental programming may contribute to the behavioural changes observed in mental illness. In recent decades, rodent studies have significantly advanced our understanding of how early life stress (ELS) affects brain development and behaviour. These studies reveal that ELS has long-term consequences on the brain such as impairment of adult hippocampal neurogenesis, altering learning and memory. Despite such advances, several key questions remain inadequately answered, including a comprehensive overview of brain regions and molecular pathways that are altered by ELS and how ELS-induced molecular changes ultimately lead to behavioural changes in adulthood. The zebrafish represents a novel ELS model, with the potential to contribute to answering some of these questions. The zebrafish offers some important advantages such as the ability to non-invasively modulate stress hormone levels in a whole animal and to visualise whole brain activity in freely behaving animals. This review discusses the current status of the zebrafish ELS field and its potential as a new ELS model.

Childhood trauma, the stress response and metabolic syndrome: A focus on DNA methylation

Childhood trauma (CT) is well established as a potent risk factor for the development of mental disorders. However, the potential of adverse early experiences to exert chronic and profound effects on physical health, including aberrant metabolic phenotypes, has only been more recently explored. Among these consequences is metabolic syndrome (MetS), which is characterised by at least three of five related cardiometabolic traits: hypertension, insulin resistance/hyperglycaemia, raised triglycerides, low high-density lipoprotein and central obesity. The deleterious effects of CT on health outcomes may be partially attributable to dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which coordinates the response to stress, and the consequent fostering of a pro-inflammatory environment. Epigenetic tags, such as DNA methylation, which are sensitive to environmental influences provide a means whereby the effects of CT can be biologically embedded and persist into adulthood to affect health and well-being. The methylome regulates the transcription of genes involved in the stress response, metabolism and inflammation. This narrative review examines the evidence for DNA methylation in CT and MetS in order to identify shared neuroendocrine and immune correlates that may mediate the increased risk of MetS following CT exposure. Our review specifically highlights differential methylation of FKBP5, the gene that encodes FK506-binding protein 51 and has pleiotropic effects on stress responding, inflammation and energy metabolism, as a central candidate to understand the molecular aetiology underlying CT-associated MetS risk.

Association between childhood maltreatment, psychopathology and DNA methylation of genes involved in stress regulation: Evidence from a study in Borderline Personality Disorder

Previous research suggests that childhood maltreatment is associated with epigenetic modification of genes involved in hypothalamic-pituitary-adrenal (HPA) functioning, which could cause dysregulation of the stress response system. If pervasive, this may be associated with the development of stress-related disorder in adults, including affective disorders, anxiety disorders, post-traumatic stress disorder (PTSD) or borderline-personality disorder (BPD). The majority of studies have focused on DNA methylation of the glucocorticoid receptor gene (NR3C1) and the FKBP5 encoding gene, which regulates the sensitivity of the glucocorticoid receptor (GR). How methylation of NR3C1 and FKBP5 interferes with childhood adversity and psychopathology as well as empathy is an under-researched issue. Here, we sought to investigate the association of childhood maltreatment in a sample of 89 individuals (44 healthy participants and 45 patients diagnosed with BPD) with the methylation of the 1_F promoter region of NR3C1 and the intron 7 of FKBP5 as well as with different measures of psychopathology and empathy. Methylation of FKBP5 (bin 2) correlated with anxiety (SCL-90-R) and the global psychopathological symptom load index (GSI), as well as with lower empathic perspective-taking abilities. Psychopathology and empathy impairments correlated with the level of childhood maltreatment. No difference in FKBP5 methylation was observed between the clinical and the non-clinical group. Methylation of NR3C1 was lower in BPD patients compared to controls, yet with small differences. The results are discussed regarding their biological relevance, including possible evolutionary explanations. In short, the regulation of the GR sensitivity by methylation of FKBP5 correlated with psychopathology and empathy scores, while no correlation emerged with the severity of childhood adversity.

Prenatal programming of depression: cumulative risk or mismatch in the Ontario Child Health Study?

Consistent with cumulative risk hypotheses of psychopathology, studies examining prenatal adversity and later mental health largely suggest that pre and postnatal stress exposures have summative effects. Fewer data support that a mismatch in stress levels between pre- and postnatal life increases risk (the mismatch hypothesis). In this retrospective cohort study using data from the 1983 Ontario Child Health Study (OCHS), we examined interactions between birth weight status and childhood/adolescent stress to predict major depression in adulthood. Ninety-five participants born at low birth weight (LBW; <2500 g) and 972 normal birth weight (NBW) control participants completed the Composite International Diagnostic Interview Short-Form Major Depression module at 21-34 years of age. A youth risk scale consisting of five stressful exposures (family dysfunction, socioeconomic disadvantage, parental criminality, maternal mental illness, exposure to other life stresses) indexed child/adolescent adversity. Birth weight groups did not differ by childhood risk score nor depression levels. A significant interaction was observed between birth weight and the youth risk scale whereby exposure to increasing levels of exposure to childhood/adolescent adversity predicted increased levels of depression in the NBW group, but lower rates in those born at LBW. Consistent with the mismatch hypothesis, data from a large, longitudinally followed cohort suggest that the mental health of adults born LBW may be more resilient to the adverse effects of childhood/adolescent stress. Taken in the context of previous studies of low birth weight infants, these findings suggest that the nature of associations between gestational stress and later mental health may depend on the magnitude of prenatal stress exposure, as well as the degree of resilience and/or plasticity conferred by their early-life environment.

How are social determinants of health integrated into epigenetic research? A systematic review

OBJECTIVE

We systematically review the literature on social epigenetics, examining how empirical research to date has conceptualized and operationalized social determinants of health (SDOH).

METHODS

Using comprehensive search procedures, we identified studies that consider the impact of SDOH on DNA methylation (DNAm), the most common measure of epigenetic change in research on human adult populations. We analyzed the studies to determine: 1) which populations and environments have been investigated in the literature; 2) how SDOH are defined and operationalized; 3) which SDOH have been linked to DNAm; and 4) what lessons from the SDOH literature can be better integrated into future studies exploring the social determinants of health and epigenetic outcomes.

RESULTS

We identified 67 studies, with 39 to 8397 participants. The SDOH most commonly considered were early life socioeconomic exposures and early life trauma or mental health. Our review highlights four broad challenges: a) high dependence on convenience sampling, b) limited racial/ethnic, and geographic diversity in sampling frames, c) overreliance on individual sociodemographic characteristics as proxies for broader stratification processes, and d) a focus on downstream social determinants of health and individualized experiences with social stressors.

CONCLUSIONS

Future social epigenetics research should prioritize larger, more diverse and representative population-based samples and employ the SDOH framework to better inform the conceptualization of research questions and interpretation of findings. In particular, the simplified depiction of race/ethnicity, gender, and socioeconomic status as individual-level characteristics should be updated with an explicit acknowledgement that these characteristics are more accurately interpreted as cues used by society to differentiate subpopulations. Social epigenetics research can then more clearly elucidate the biological consequences of these social exposures for patterns of gene expression, subsequent disease etiology, and health inequities.

The impact of psychopathology, social adversity and stress-relevant DNA methylation on prospective risk for post-traumatic stress: A machine learning approach

BACKGROUND

A range of factors have been identified that contribute to greater incidence, severity, and prolonged course of post-traumatic stress disorder (PTSD), including: comorbid and/or prior psychopathology; social adversity such as low socioeconomic position, perceived discrimination, and isolation; and biological factors such as genomic variation at glucocorticoid receptor regulatory network (GRRN) genes. This complex etiology and clinical course make identification of people at higher risk of PTSD challenging. Here we leverage machine learning (ML) approaches to identify a core set of factors that may together predispose persons to PTSD.

METHODS

We used multiple ML approaches to assess the relationship among DNA methylation (DNAm) at GRRN genes, prior psychopathology, social adversity, and prospective risk for PTS severity (PTSS).

RESULTS

ML models predicted prospective risk of PTSS with high accuracy. The Gradient Boost approach was the top-performing model with mean absolute error of 0.135, mean square error of 0.047, root mean square error of 0.217, and R2 of 95.29%. Prior PTSS ranked highest in predicting the prospective risk of PTSS, accounting for >88% of the prediction. The top ranked GRRN CpG site was cg05616442, in AKT1, and the top ranked social adversity feature was loneliness.

CONCLUSION

Multiple factors including prior PTSS, social adversity, and DNAm play a role in predicting prospective risk of PTSS. ML models identified factors accounting for increased PTSS risk with high accuracy, which may help to target risk factors that reduce the likelihood or course of PTSD, potentially pointing to approaches that can lead to early intervention.

LIMITATION

One of the limitations of this study is small sample size.

Biopsychosocial correlates of psychological distress in Latina mothers

BACKGROUND

Few studies have explored the relationship between psychological, psychosocial and biological factors among Latinas. An integrated understanding of how these factors associate with psychological distress is necessary for the development of culturally relevant screening tools and interventions. The study aim was to examine the relationships among (a) psychological distress symptoms, (b) psychosocial factors (discrimination, acculturation, acculturative stress, economic hardship), and (c) biological (DNA methylation of stress-related genes) factors among Latinas during pregnancy and postpartum period.

METHODS

A sample of 150 pregnant Latinas completed the Inventory of Depression and Anxiety Symptoms II (IDAS-II), psychosocial questionnaires (discrimination, acculturation, acculturative stress, economic hardship) before (24-32 weeks) and after gestation (4-6 weeks postpartum). Blood samples were collected between 24-32 weeks gestation. Correlations were determined between psychosocial and biological measures and psychological distress measures. Multivariable linear regression models were conducted to assess the relationships between IDAS and stressors.

RESULTS

Several correlations among psychosocial measures,DNA methylation factors and IDAS-II variables were identified. Among the psychosocial measures, everyday discrimination was the most strongly and consistently associated with IDAS-II. DNA methylation of NR3C1 affects the associations between psychological and psychosocial distress.

LIMITATIONS

We only assessed DNA methylation during pregnancy and focused on four HPA-related genes. Longitudinal assessment of DNA methylation and genome-wide analysis can provide a better picture of the role of methylation in psychological distress.

CONCLUSIONS

This work may assist clinicians and policy makers in effectively recognizing and preventing maternal mental health disparities based on discrimination and other psychosocial stressors in at-risk groups.

A systematic review of childhood maltreatment and DNA methylation: candidate gene and epigenome-wide approaches

Childhood maltreatment is a major risk factor for chronic and severe mental and physical health problems across the lifespan. Increasing evidence supports the hypothesis that maltreatment is associated with epigenetic changes that may subsequently serve as mechanisms of disease. The current review uses a systematic approach to identify and summarize the literature related to childhood maltreatment and alterations in DNA methylation in humans. A total of 100 empirical articles were identified in our systematic review of research published prior to or during March 2020, including studies that focused on candidate genes and studies that leveraged epigenome-wide data in both children and adults. Themes arising from the literature, including consistent and inconsistent patterns of results, are presented. Several directions for future research, including important methodological considerations for future study design, are discussed. Taken together, the literature on childhood maltreatment and DNA methylation underscores the complexity of transactions between the environment and biology across development.

Antidepressant treatment is associated with epigenetic alterations of Homer1 promoter in a mouse model of chronic depression

BACKGROUND

Understanding the neurobiology of depression and the mechanism of action of therapeutic measures is currently a research priority. We have shown that the expression of the synaptic protein Homer1a correlates with depression-like behavior and its induction is a common mechanism of action of different antidepressant treatments. However, the mechanism of Homer1a regulation is still unknown.

METHODS

We combined the chronic despair mouse model (CDM) of chronic depression with different antidepressant treatments. Depression-like behavior was characterized by forced swim and tail suspension tests, and via automatic measurement of sucrose preference in IntelliCage. The Homer1 mRNA expression and promoter DNA methylation were analyzed in cortex and peripheral blood by qRT-PCR and pyrosequencing.

RESULTS

CDM mice show decreased Homer1a and Homer1b/c mRNA expression in cortex and blood samples, while chronic treatment with imipramine and fluoxetine or acute ketamine application increases their level only in the cortex. The quantitative analyses of the methylation of 7 CpG sites, located on the Homer1 promoter region containing several CRE binding sites, show a significant increase in DNA methylation in the cortex of CDM mice. In contrast, antidepressant treatments reduce the methylation level.

LIMITATIONS

Homer1 expression and promotor methylation were not analyzed in different blood cell types. Other CpG sites of Homer1 promoter should be investigated in future studies. Our experimental approach does not distinguish between methylation and hydroxymethylation.

CONCLUSIONS

We demonstrate that stress-induced depression-like behavior and antidepressant treatments are associated with epigenetic alterations of Homer1 promoter, providing new insights into the mechanism of antidepressant treatment.

Role of DNA Methylation in Mediating Genetic Risk of Psychiatric Disorders

Psychiatric disorders are common, complex, and heritable conditions estimated to be the leading cause of disability worldwide. The last decade of research in genomics of psychiatry, performed by multinational, and multicenter collaborative efforts on hundreds of thousands of mental disorder cases and controls, provided invaluable insight into the genetic risk variants of these conditions. With increasing cohort sizes, more risk variants are predicted to be identified in the near future, but there appears to be a knowledge gap in understanding how these variants contribute to the pathophysiology of psychiatric disorders. Majority of the identified common risk single-nucleotide polymorphisms (SNPs) are non-coding but are enriched in regulatory regions of the genome. It is therefore of great interest to study the impact of identified psychiatric disorders' risk SNPs on DNA methylation, the best studied epigenetic modification, playing a pivotal role in the regulation of transcriptomic processes, brain development, and functioning. This work outlines the mechanisms through which risk SNPs can impact DNA methylation levels and provides a summary of current evidence on the role of DNA methylation in mediating the genetic risk of psychiatric disorders.

Increased methylation of NR3C1 and SLC6A4 is associated with blunted cortisol reactivity to stress in major depression

Background

Epigenetic changes are considered the main mechanisms behind the interplay of environment and genetic susceptibility in major depressive disorder (MDD). However, studies focusing on epigenetic dysregulation of the HPA axis stress response in MDD are lacking. Our objective was to simultaneously asses DNA methylation of the glucocorticoid receptor gene (NR3C1) and serotonin transporter gene (SLC6A4) and HPA axis response to stress in MDD.

Methods

We recruited 80 depressed inpatients and 58 gender and age matched healthy controls. All participants underwent the Trier Social Stress Test (TSST) and salivary cortisol was repeatedly measured to assess HPA axis reactivity. DNA methylation of the NR3C1 (exon 1 F) and SLC6A4 CpG islands was quantified from whole blood DNA. In the MDD group, clinical assessment was repeated at 8-week follow-up to test the predictive potential of DNA methylation for symptom improvement.

Results

Depressed patients had blunted cortisol reactivity to TSST compared to healthy controls (p = 0.01). In addition, they presented with increased average SLC6A4 (p = 0.003) and NR3C1 methylation (p = 0.03), as well as methylation of two individual NR3C1 CpG loci overlapping with the NGFI-A-binding sites (CpG12 and CpG20). Methylation of one of these two loci (CpG20) predicted lower symptom improvement at the follow-up (p = 0.007). Both, average NR3C1 and SLC6A4 methylation were associated with lower cortisol reactivity in the MDD group and explained about 16% of variability in cortisol response to TSST.

Conclusions

We provide evidence of the role of NR3C1 and SLC6A4 DNA methylation in HPA axis dysregulation in MDD, which needs to be further explored.

A legacy of fear: Physiological evidence for intergenerational effects of trauma exposure on fear and safety signal learning among African Americans

OBJECTIVE

To determine the influence of maternal trauma and posttraumatic stress disorder (PTSD) symptoms on children's physiological response to threat and safety signals during a fear conditioning task in trauma-exposed mothers and children.

METHOD

Participants were African American mother-child dyads (N = 137; children aged 8-13 years). Mothers' trauma history and PTSD symptoms were assessed; Latent Class Analysis (LCA) was conducted from these measures to identify distinct classes. Children reported violence exposure and completed a differential fear conditioning task using fear-potentiated startle (FPS) responses to conditioned danger (CS+) and safety (CS-) signals.

RESULTS

Four classes of maternal trauma history and PTSD symptoms emerged: 1) Lower Trauma, 2) Moderate Trauma, 3) High Sexual Abuse, and 4) High Trauma and PTSD Symptoms. Children's FPS to CS + and CS- were tested with maternal class as the between-subjects factor. FPS to the danger signal was not significantly different across maternal classes, but FPS to safety (CS-) was significantly higher for the Lower Trauma and High Trauma and PTSD Symptoms classes than either the Moderate Trauma or the High Sexual Abuse classes.

CONCLUSIONS

Results indicate that maternal trauma impacts children's ability to modulate fear responses in the presence of a safety signal, independent of the children's own trauma exposure. To our knowledge, this is the first study to demonstrate that children's fear inhibition is impacted by maternal trauma exposure. Prior studies have linked fear inhibition to mental health outcomes, highlighting the need to understand intergenerational modulation of fear learning and physiology.

DNA methylation of IL-4 gene and the association with childhood trauma in panic disorder

Increasing evidence suggests that aberrations in the immune-inflammatory pathways contribute to the pathophysiology of panic disorder (PD). We aimed to investigate whether an aberrant DNA methylation of the inflammation-related genes in the development of PD, including CCL3, CRP, CSF2, CXCL8, IFNG, IL12B, IL1A, IL-4, IL-6, TNF. Then, the effect of childhood trauma(CT) on methylation levels of  inflammation-related genes and the severity of PD was also investigated. We compared the methylation levels of the inflammation-related genes between 113 patients with PD and 130 matched healthy controls using MethylTarget approach. In addition, the Hamilton Anxiety Rating Scale (HAMA), Panic Disorder Severity Scale (PDSS) and Childhood Trauma Questionnaire-28 item Short Form (CTQ-28) were respectively assessed to all subjects. The result found that the methylation levels of IL-4 gene was significantly higher in PD patients than controls. ROC results found that the IL-4 gene had a sensitivity of 52.3% and a specificity of 74.6%. The methylation levels of IL-4 gene was significantly positively related to the severity of panic and anxiety. Finally, the hypermethylation of CSF2, CXCL8 and IL-4 genes was significantly associated with higher CT.

Effect of Early Life Stress on the Epigenetic Profiles in Depression

Depression is one of the most common mental disorders and has caused an overwhelming burden on world health. Abundant studies have suggested that early life stress may grant depressive-like phenotypes in adults. Childhood adversities that occurred in the developmental period amplified stress events in adulthood. Epigenetic-environment interaction helps to explain the role of early life stress on adulthood depression. Early life stress shaped the epigenetic profiles of the HPA axis, monoamine, and neuropeptides. In the context of early adversities increasing the risk of depression, early life stress decreased the activity of the glucocorticoid receptors, halted the circulation and production of serotonin, and reduced the molecules involved in modulating the neurogenesis and neuroplasticity. Generally, DNA methylation, histone modifications, and the regulation of non-coding RNAs programmed the epigenetic profiles to react to early life stress. However, genetic precondition, subtypes of early life stress, the timing of epigenetic status evaluated, demographic characteristics in humans, and strain traits in animals favored epigenetic outcomes. More research is needed to investigate the direct evidence for how early life stress-induced epigenetic changes contribute to the vulnerability of depression.

Adverse childhood experiences, epigenetics and telomere length variation in childhood and beyond: a systematic review of the literature

A systematic review following PRISMA guidelines was conducted to answer the question: What epigenetic, telomeric and associated biological changes are associated with exposure to adverse childhood experiences (ACEs) in the under 12s? Using PRISMA guidelines, appropriate databases were searched. 190 papers were returned with 38 articles fully reviewed. Articles were each independently quality rated by two authors using the Crowe Critical Appraisal Tool and data were extracted. Of the 38 articles, 23 were rated as very high quality. Most study participants were adults (n = 7769) with n = 727 child participants. Only seven of the very/high-quality studies were prospective and involved children. Methylation was the most studied method of epigenetic modification. There is some evidence supporting epigenetic modification of certain markers in participants exposed to ACEs measured in adulthood. Research is lacking on non-coding aspects of the epigenome and on coding aspects other than DNA methylation. There is some evidence of a more powerful effect on telomere length if physical neglect was involved. Much further work is required to model biological and psychological effects of epigenetic changes during childhood using prospective study designs. The effect of ACEs on the cellular ageing process during childhood is inadequately investigated and relies solely on measure of telomere length. Future research suggestions are proposed.

Childhood maltreatment and HPA axis gene expression in bipolar disorders: A gene network analysis

INTRODUCTION

Bipolar disorder (BD) is highly associated with childhood maltreatment (CM), the exposure to such early adversity being suggested to disrupt the expression of several biological pathways. This study aims at exploring associations between the mRNA levels of 9 HPA axis genes in lymphoblastoid cell lines from patients with BD according to their self-reported exposure to CM.

METHODS

The sample consisted of 33 Caucasian patients with a diagnosis of BD type 1, assessed for the exposure to CM with the Childhood Trauma Questionnaire (CTQ). Quantitative RT-PCR was performed on 9 transcripts of the HPA axis genes: DGKH, FKBP5, NR3C1, SGK1, SGK2, SGK3, SKA2, STAT5A and UCN. RT-qPCR data were analyzed using the method of disjoint gene networks with SARP.compo package for R.

RESULTS

We found no associations between CTQ total score and the amount of HPA axis transcripts neither in univariate analyses, nor with network analyses. Emotional abuse (EA) was associated with a significant decreased expression of two transcripts, DGKH (p = 0.009) and NR3C1 (p = 0.04). This was confirmed by the disjoint network analysis, which showed that NR3C1 and DGKH were expressed differently from the rest of the HPA axis network in presence of emotional abuse.

DISCUSSION

This study described the expression levels of a comprehensive set of HPA axis genes according to childhood maltreatment in a sample of patients with BD type 1 and suggested that emotional abuse decreased the expression of NR3C1 and DGKH. Our results require further replication in independent larger samples.

Epigenetic alterations associated with childhood trauma and adult mental health outcomes: A systematic review

Objectives: Multiple, chronic and repeated trauma exposure in childhood is associated with adverse mental health outcomes in adulthood. In this paper we synthesise the literature on epigenetic modifications in childhood trauma (CT) and the mediating effects of differential epigenetic mechanisms on the association between CT and the later onset of psychiatric disorders.Methods: We reviewed the literature up to March 2018 in four databases: PubMed, Web of Science, EBSCOhost and SCOPUS. Non-human studies were excluded. All studies investigating CT exposure both in healthy adults (18 years and older) and adults with psychiatric disorders were included.Results: Thirty-six publications were included. For mood disorders, methylation of the glucocorticoid receptor NR3C1 gene, specifically at the NGFI-A binding site in exon 1F, and correlation with CT was a robust finding. Several studies documented differential methylation of SLC6A4, BDNF, OXTR and FKBP5 in association with CT. Common pathways identified include neuronal functioning and maintenance, immune and inflammatory processes, chromatin and histone modification, and transcription factor binding.Conclusions: A variety of epigenetic mediators that lie on a common pathway between CT and psychiatric disorders have been identified, although longitudinal studies and consistency in methodological approach are needed to disentangle cause and effect associations.

Synergistic effects of depression and NR3C1 methylation on prognosis of acute coronary syndrome

High levels of methylation in the GR gene (nuclear receptor subfamily 3, group C, member 1; NR3C1) have been associated with depression and cardiovascular risk. This study aimed to investigate whether NR3C1 methylation status was associated with the long-term prognosis of acute coronary syndrome (ACS) considering depression and cardiovascular status at the early phase of ACS. A total of 969 patients with recent ACS were recruited at a tertiary university hospital in Korea. Baseline evaluations were made from 2007 to 2012, including DSM-IV depressive disorder, NR3C1 methylation, and various demographic and clinical characteristics such as cardiovascular risk markers. Over a 5~12 year follow-up after the index ACS, time to major adverse cardiac event (MACE) was investigated using Cox regression models. Higher NR3C1 methylation status was associated with depression and several cardiovascular risk markers at baseline. NR3C1 hypermethylation predicted worse long-term prognosis of ACS only in the presence of depressive disorder with significant synergistic interaction terms and independent of potential confounding factors. Synergistic effects of depressive disorder and NR3C1 hypermethylation on long-term cardiac outcomes in ACS were found. NR3C1 methylation status represents a candidate prognostic biomarker for ACS in combination with a diagnosis of depressive disorder. Further research is needed to ascertain the generalisability of these findings.

Placental Gene Expression and Offspring Temperament Trajectories: Predicting Negative Affect in Early Childhood

Exposure to prenatal stress increases offspring risk for long-term neurobehavioral impairments and psychopathology, such as Attention Deficit Hyperactivity Disorder (ADHD). Epigenetic regulation of glucocorticoid pathway genes may be a potential underlying mechanism by which maternal conditions 'program' the fetal brain for downstream vulnerabilities. The present study aims to investigate whether mRNA expression of glucocorticoid pathway genes in the placenta predict offspring negative affect during early childhood (between 6 and 24 months). Participants include 318 mother-child dyads participating in a longitudinal birth cohort study. Placental mRNA expression of glucocorticoid pathway genes (HSD11B1, HSD11B2, NR3C1, NCOR2) were profiled and negative affect traits of the offspring were measured at 6, 12, 18, and 24 months. HSD11B1 mRNA expression significantly predicted negative affect (β = -.09, SE = .04; p = .036), and Distress to Limitations trajectories (β = -.13, SE = .06; p = .016). NCOR2 mRNA expression significantly predicted Distress to Limitations (β = .43, SE = .21; p = .047), and marginally predicted Sadness trajectories (β = .39, SE = .21; p = .068). HSD11B2 and NR3C1 did not predict trajectories of Negative Affect or subscale scores. Infant negative affect traits were assessed via maternal self-report, and deviated from linearity across follow-up. mRNA expression of glucocorticoid pathway genes in the placenta may be a potentially novel tool for early identification of infants at greater risk for elevated negative affect. Further study is needed to validate the utility of mRNA expression of glucocorticoid pathway genes in the placenta.

Epigenetic predictors of all-cause mortality are associated with objective measures of neighborhood disadvantage in an urban population

BACKGROUND

Neighborhood characteristics are robust predictors of overall health and mortality risk for residents. Though there has been some investigation of the role that molecular indicators may play in mediating neighborhood exposures, there has been little effort to incorporate newly developed epigenetic biomarkers into our understanding of neighborhood characteristics and health outcomes.

METHODS

Using 157 participants of the Detroit Neighborhood Health Study with detailed assessments of neighborhood characteristics and genome-wide DNA methylation profiling via the Illumina 450K methylation array, we assessed the relationship between objective neighborhood characteristics and a validated DNA methylation-based epigenetic mortality risk score (eMRS). Associations were adjusted for age, race, sex, ever smoking, ever alcohol usage, education, years spent in neighborhood, and employment. A secondary model additionally adjusted for personal neighborhood perception. We summarized 19 neighborhood quality indicators assessed for participants into 9 principal components which explained over 90% of the variance in the data and served as metrics of objective neighborhood quality exposures.

RESULTS

Of the nine principal components utilized for this study, one was strongly associated with the eMRS (β = 0.15; 95% confidence interval = 0.06-0.24; P = 0.002). This principal component (PC7) was most strongly driven by the presence of abandoned cars, poor streets, and non-art graffiti. Models including both PC7 and individual indicators of neighborhood perception indicated that only PC7 and not neighborhood perception impacted the eMRS. When stratified on neighborhood indicators of greenspace, we observed a potentially protective effect of large mature trees as this feature substantially attenuated the observed association.

CONCLUSION

Objective measures of neighborhood disadvantage are significantly associated with an epigenetic predictor of mortality risk, presenting a potential novel avenue by which neighborhood-level exposures may impact health. Associations were independent of an individual's perception of their neighborhood and attenuated by neighborhood greenspace features. More work should be done to determine molecular risk factors associated with neighborhoods, and potentially protective neighborhood features against adverse molecular effects.

Childhood maltreatment and DNA methylation: A systematic review

DNA methylation (DNAm) - an epigenetic process that regulates gene expression - may represent a mechanism for the biological embedding of early traumatic experiences, including childhood maltreatment. Here, we conducted the first systematic review of human studies linking childhood maltreatment to DNAm. In total, 72 studies were included in the review (2008-2018). The majority of extant studies (i) were based on retrospective data in adults, (ii) employed a candidate gene approach (iii) focused on global maltreatment, (iv) were based on easily accessible peripheral tissues, typically blood; and (v) were cross-sectional. Two-thirds of studies (n = 48) also examined maltreatment-related outcomes, such as stress reactivity and psychiatric symptoms. While findings generally support an association between childhood maltreatment and altered patterns of DNAm, factors such as the lack of longitudinal data, low comparability across studies as well as potential genetic and 'pre-exposure' environmental confounding currently limit the conclusions that can be drawn. Key challenges are discussed and concrete recommendations for future research are provided to move the field forward.

Epigenetic Biomarkers for Environmental Exposures and Personalized Breast Cancer Prevention

Environmental and lifestyle factors are believed to account for >80% of breast cancers; however, it is not well understood how and when these factors affect risk and which exposed individuals will actually develop the disease. While alcohol consumption, obesity, and hormone therapy are some known risk factors for breast cancer, other exposures associated with breast cancer risk have not yet been identified or well characterized. In this paper, it is proposed that the identification of blood epigenetic markers for personal, in utero, and ancestral environmental exposures can help researchers better understand known and potential relationships between exposures and breast cancer risk and may enable personalized prevention strategies.

Risk factors for depression in adults: NR3C1 DNA methylation and lifestyle association

OBJECTIVE

The aim of this study was to verify determinant factors for depression and analyze the relationship between possible changes in HPA axis and depression, in this case NR3C1 DNA methylation and serum cortisol levels.

METHODS

349 adult volunteers were recruited to evaluate depression, socio-demographic, economic and lifestyle factors, serum cortisol levels and NR3C1 DNA methylation by pyrosequencing. Depression determinant factors were investigated using a Poisson regression model with robust variance (p < 0.05).

RESULTS

Poisson regression with robust variance adjusted by gender, tobacco use, self-perceived stress, leisure activity, suicidal ideation, low cortisol levels and NR3C1 DNA methylation was performed and predicted risk factors for depression. Furthermore, depressive volunteers showed a significant increase in NR3C1 DNA methylation when compared to healthy volunteers.

CONCLUSIONS

This findings provide a basis for understanding the role of HPA axis in depression, especially its regulation by NR3C1 DNA methylation. Furthermore, it emphasizes the stressful lifestyle risk factors (female, tobacco uso, self perceived stress, leisure activities absence and suicidal ideation) that can contribute to future research and the search for public health policies to improve quality of live, mental and general health.

Investigation of MORC1 DNA methylation as biomarker of early life stress and depressive symptoms

Early life stress (ELS) is associated with an increased risk of depression and this association may be mediated by epigenetic mechanisms. A previous epigenome-wide DNA methylation (DNAm) study investigating human newborns and two animal models of ELS suggested that the epigenetic regulator MORC1 is differentially methylated following ELS. The ELS-induced DNAm alterations were long-lasting in the animal models. However, whether this finding is also transferable to humans experiencing ELS in childhood was not investigated. Further, MORC1 may provide a link between ELS and adult depression, as MORC1 DNAm and genetic variants were found to be associated with depressive symptoms in humans. In the present study, we investigated the validity of MORC1 DNAm as a biomarker of ELS in humans and its role in linking ELS to depression later in life by studying childhood maltreatment. We analyzed whole blood MORC1 DNAm in an adult cohort (N = 151) that was characterized for both the presence of depressive symptoms and childhood maltreatment. Further, we investigated the association between MORC1 DNAm, depressive symptoms and childhood maltreatment in two additional cohorts (N = 299, N = 310). Overall, our data do not indicate an association of MORC1 DNAm with childhood maltreatment. An association of MORC1 DNAm with depressive symptoms was present in all cohorts, but was inconsistent in the specific CpG sites associated and the direction of effect (Tuebingen cohort: standardized β = 0.16, unstandardized β = 0.01, 95% CI [-0.0004, -0.0179], p = 0.061, PReDICT cohort: standardized β = -0.12, unstandardized β = -0.01, 95% CI [-0.0258, -0.0003], p = 0.045), Grady cohort: standardized β = 0.16, unstandardized β = 0.008, 95% CI [0.0019, 0.0143], p = 0.01). Our study thus suggests that peripheral MORC1 DNAm cannot serve as biomarker of childhood maltreatment in adults, but does provide further indication for the association of MORC1 DNAm with depressive symptoms.