DNA Methylation, Behavior and Early Life Adversity

Stress from early life to adulthood: Is there a protective role of cognitive control?

Early life events can have long-lasting effects that may impact the quality of life into adulthood. The link between childhood adversities and adult mental and physical health is well documented, however, the underlying mechanisms remain poorly understood. Executive functions are assumed to be a key factor in successfully dealing with cognitive-emotional challenges thereby contributing to stress resilience and mental health across the lifespan. Here, we examined whether cognitive control moderates the link between early life adversity and depression. Data was available from a sample of 424 participants aged 20-70 years (Clinicaltrials.gov: NCT05155397). They performed in the Stroop task and behavior as well as frontal theta power were recorded. Negative childhood experiences were assessed with the Childhood Trauma Questionnaire (CTQ), chronic stress was measured with the Trier Inventory for Chronic Stress (TICS) and depression symptoms with Beck's Depression Inventory (BDI). The CTQ predicted symptoms of chronic stress and depression. Regression models pointed to the TICS as a crucial mediator in the relationship between CTQ and BDI. However, parameters of cognitive control demonstrated a rather weak effect as moderators. These results indicate that chronic stress is an important mediator linking childhood trauma to depression but suggest only a limited role for cognitive control.

Maternally derived avian corticosterone affects offspring genome-wide DNA methylation in a passerine species

Avian embryos develop in an egg composition which reflects both maternal condition and the recent environment of their mother. In birds, yolk corticosterone (CORT) influences development by impacting pre- and postnatal growth, as well as nestling stress responses and development. One possible mechanism through which maternal CORT may affect offspring development is via changes to offspring DNA methylation. We sought to investigate this, for the first time in birds, by quantifying the impact of manipulations to maternal CORT on offspring DNA methylation. We non-invasively manipulated plasma CORT concentrations of egg-laying female zebra finches (Taeniopygia castanotis) with an acute dose of CORT administered around the time of ovulation and collected their eggs. We then assessed DNA methylation in the resulting embryonic tissue and in their associated vitelline membrane blood vessels, during early development (5 days after lay), using two established methods - liquid chromatography-mass spectrometry (LC-MS) and methylation-sensitive amplification fragment length polymorphism (MS-AFLP). LC-MS analysis showed that global DNA methylation was lower in embryos from CORT-treated mothers, compared to control embryos. In contrast, blood vessel DNA from eggs from CORT-treated mothers showed global methylation increases, compared to control samples. There was a higher proportion of global DNA methylation in the embryonic DNA of second clutches, compared to first clutches. Locus-specific analyses using MS-AFLP did not reveal a treatment effect. Our results indicate that an acute elevation of maternal CORT around ovulation impacts DNA methylation patterns in their offspring. This could provide a mechanistic understanding of how a mother's experience can affect her offspring's phenotype.

Early life adversity drives sex-dependent changes in 5-mC DNA methylation of parvalbumin cells in the prefrontal cortex in rats

Early life adversity (ELA) can result in increased risk for developing affective disorders, such as anxiety or depression, later in life, with women showing increased risk. Interactions between an individual's genes and their environment play key roles in producing, as well as mitigating, later life neuropathology. Our current understanding of the underlying epigenomic drivers of ELA associated anxiety and depression are limited, and this stems in part from the complexity of underlying biochemical processes associated with how early experiences shapes later life behavior. Epigenetic alterations, or experience-driven modifications to DNA, can be leveraged to understand the interplay between genes and the environment. The present study characterized DNA methylation patterning, assessed via evaluation of 5-methylcytosine (5-mC), following ELA in a Sprague Dawley rat model of ELA induced by early caregiver deprivation. This study utilized maternal separation to investigate sex- and age-specific outcomes of ELA on epigenetic patterning in parvalbumin (PV)-containing interneurons in the prefrontal cortex (PFC), a subpopulation of inhibitory neurons which are associated with ELA and affective dysfunction. While global analysis of 5-mC methylation and CpG site specific pyrosequencing of the PV promoter, Pvalb, showed no obvious effects of ELA, when analyses were restricted to assessing 5-mC intensity in colocalized PV cells, there were significant sex and age dependent effects. We found that ELA leads sex-specific changes in PV cell counts, and that cell counts can be predicted by 5-mC intensity, with males and females showing distinct patterns of methylation and PV outcomes. ELA also produced sex-specific effects in corticosterone reactivity, with juvenile females showing a blunted stress hormone response compared to controls. Overall, ELA led to a sex-specific developmental shift in PV profile, which is comparable to profiles that are seen at a later developmental timepoint, and this shift may be mediated in part by epigenomic alterations driven by altered DNA methylation.

Placental accelerated aging in antenatal depression

BACKGROUND

Antenatal maternal depression is associated with poor pregnancy outcomes and long-term effects on the offspring. Previous studies have identified links between antenatal depression and placental DNA methylation and between placental epigenetic aging and poor pregnancy outcomes, such as preterm labor and preeclampsia. The relationship between antenatal depression and poor pregnancy outcomes may be partly mediated via placental aging.

OBJECTIVE

This study aimed to investigate whether antenatal depressive symptoms are associated with placental epigenetic age acceleration, an epigenetic aging clock measure derived from the difference between methylation age and gestational age at delivery.

STUDY DESIGN

The study included 301 women who provided placenta samples at delivery as part of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Growth Studies - Singletons that recruited participants from diverse race and ethnic groups at 12 US clinical sites (2009-2013). Women underwent depression screening using the Edinburgh Postnatal Depression Scale up to 6 times across the 3 trimesters of pregnancy. Depressive symptoms status was determined for each pregnancy trimester using an Edinburgh Postnatal Depression Scale score, in which a score of ≥10 was defined as having depressive symptoms and a score of <10 was defined as not having depressive symptoms. Placental DNA methylation was profiled from placenta samples. Placental epigenetic age was estimated using a methylation-based age estimator (placental "epigenetic clock") that has previously been found to have high placental gestational age prediction accuracy for uncomplicated term pregnancies. Placental age acceleration was defined to be the residual upon regressing the estimated epigenetic age on gestational age at delivery. Associations between an Edinburgh Postnatal Depression Scale score of ≥10 and an Edinburgh Postnatal Depression Scale score of <10 in the first, second, and third trimesters of pregnancy (ie, depressive symptoms vs none in each trimester) and placental age acceleration were tested using multivariable linear regression adjusting for maternal age, parity, race and ethnicity, and employment.

RESULTS

There were 31 (10.3%), 48 (16%), and 49 (16.4%) women with depressive symptoms (ie, Edinburgh Postnatal Depression Scale score of ≥10) in the first, second, and third trimesters of pregnancy, respectively. Of these women, 21 (7.2%) had sustained first- and second-trimester depressive symptoms, 19 (7%) had sustained second- and third-trimester depressive symptoms, and 12 (4.8%) had sustained depressive symptoms throughout pregnancy. Women with depressive symptoms in the second trimester of pregnancy had 0.41 weeks higher placental age acceleration than women without depressive symptoms during the second trimester of pregnancy (β=0.21 weeks [95% confidence interval, -0.17 to 0.58; P=.28] during the first trimester of pregnancy; β=0.41 weeks [95% confidence interval, 0.10-0.71; P=.009] during the second trimester of pregnancy; β=0.17 weeks [95% confidence interval, -0.14 to 0.47; P=.29] during the third trimester of pregnancy). Sustained first- and second-trimester depressive symptoms were associated with 0.72 weeks higher placental age acceleration (95% confidence interval, 0.29-1.15; P=.001) than no depressive symptom in the 2 trimesters. The association between second-trimester depressive symptoms and higher placental epigenetic age acceleration strengthened in the analysis of pregnancies with male fetuses (β=0.53 weeks; 95% confidence interval, 0.06-1.08; P=.03) but was not significant in pregnancies with female fetuses.

CONCLUSION

Antenatal depressive symptoms during the second trimester of pregnancy were associated with an average of 0.41 weeks of increased placental age acceleration. Accelerated placental aging may play an important role in the underlying mechanism linking antenatal depression to pregnancy complications related to placental dysfunction.

The Impacts of Early-Life Experience on Bee Phenotypes and Fitness

Across diverse animal species, early-life experiences have lifelong impacts on a variety of traits. The scope of these impacts, their implications, and the mechanisms that drive these effects are central research foci for a variety of disciplines in biology, from ecology and evolution to molecular biology and neuroscience. Here, we review the role of early life in shaping adult phenotypes and fitness in bees, emphasizing the possibility that bees are ideal species to investigate variation in early-life experience and its consequences at both individual and population levels. Bee early life includes the larval and pupal stages, critical time periods during which factors like food availability, maternal care, and temperature set the phenotypic trajectory for an individual's lifetime. We discuss how some common traits impacted by these experiences, including development rate and adult body size, influence fitness at the individual level, with possible ramifications at the population level. Finally, we review ways in which human alterations to the landscape may impact bee populations through early-life effects. This review highlights aspects of bees' natural history and behavioral ecology that warrant further investigation with the goal of understanding how environmental disturbances threaten these vulnerable species.

Study protocol for the Mindful Moms Study: A randomized controlled trial evaluating a mindful movement intervention for marginalized pregnant people experiencing depression

More than 1 in 5 pregnant people in the United States experience depressive symptoms. Although treatments exist, many people remain under- or un-treated due to concerns about stigma, side effects, and costs of medications or psychotherapy, particularly those who are marginalized (defined as those who are minoritized, low-income, or with low-educational attainment). Further, the standard depression treatments do not address social connectedness, which is a potentially modifiable factor involved in depressive symptom etiology. This protocol presents the rationale, design, and status of the two-arm longitudinal parallel group randomized controlled trial - the Mindful Moms Study - which aims to evaluate the effects and mechanisms of a group-based mindful physical activity (yoga) intervention in marginalized pregnant people with depressive symptoms (n = 200) compared to a prenatal education control group. The primary aim is to evaluate effects of group assignment on depressive symptom severity, anxiety, and perceived stress over time from baseline to six weeks postpartum. Secondary aims include understanding the role of social connectedness as a moderator of the effects and to identify genome-wide DNA methylation patterns associated with depressive symptoms and perceived social connectedness at postpartum. A focus on adequate symptom management through non-pharmacologic, accessible therapies that address social connectedness during pregnancy in marginalized women is an urgent clinical and research priority. The successful completion of this study will provide important insights into social connectedness as a mechanism to decrease depressive symptoms in a largely understudied population. Trial registration: NCT04886856.

RNA in extracellular vesicles during adolescence reveal immune, energetic and microbial imprints of early life adversity

Exposure to early life adversity (ELA), including childhood maltreatment, is one of the most significant risk factors for the emergence of neuropsychiatric disorders in adolescence and adulthood. Despite this relationship being well established, the underlying mechanisms remain unclear. One way to achieve this understanding is to identify molecular pathways and processes that are perturbed as a consequence of childhood maltreatment. Ideally, these perturbations would be evident as changes in DNA, RNA or protein profiles in easily accessible biological samples collected in the shadow of childhood maltreatment. In this study, we isolated circulating extracellular vesicles (EVs) from plasma collected from adolescent rhesus macaques that had either experienced nurturing maternal care (CONT) or maternal maltreatment (MALT) in infancy. RNA sequencing of RNA in plasma EVs and gene enrichment analysis revealed that genes related to translation, ATP synthesis, mitochondrial function and immune response were downregulated in MALT samples, while genes involved in ion transport, metabolism and cell differentiation were upregulated. Interestingly, we found that a significant proportion of EV RNA aligned to the microbiome and that MALT altered the diversity of microbiome-associated RNA signatures found in EVs. Part of this altered diversity suggested differences in prevalence of bacterial species in CONT and MALT animals noted in the RNA signatures of the circulating EVs. Our findings provide evidence that immune function, cellular energetics and the microbiome may be important conduits via which infant maltreatment exerts effects on physiology and behavior in adolescence and adulthood. As a corollary, perturbations of RNA profiles related to immune function, cellular energetics and the microbiome may serve as biomarkers of responsiveness to ELA. Our results demonstrate that RNA profiles in EVs can serve as a powerful proxy to identify biological processes that might be perturbed by ELA and that may contribute to the etiology of neuropsychiatric disorders in the aftermath of ELA.

Early-life stress lastingly impacts microglial transcriptome and function under basal and immune-challenged conditions

Early-life stress (ELS) leads to increased vulnerability to psychiatric disorders including depression later in life. Neuroinflammatory processes have been implicated in ELS-induced negative health outcomes, but how ELS impacts microglia, the main tissue-resident macrophages of the central nervous system, is unknown. Here, we determined the effects of ELS-induced by limited bedding and nesting material during the first week of life (postnatal days [P]2-9) on microglial (i) morphology; (ii) hippocampal gene expression; and (iii) synaptosome phagocytic capacity in male pups (P9) and adult (P200) mice. The hippocampus of ELS-exposed adult mice displayed altered proportions of morphological subtypes of microglia, as well as microglial transcriptomic changes related to the tumor necrosis factor response and protein ubiquitination. ELS exposure leads to distinct gene expression profiles during microglial development from P9 to P200 and in response to an LPS challenge at P200. Functionally, synaptosomes from ELS-exposed mice were phagocytosed less by age-matched microglia. At P200, but not P9, ELS microglia showed reduced synaptosome phagocytic capacity when compared to control microglia. Lastly, we confirmed the ELS-induced increased expression of the phagocytosis-related gene GAS6 that we observed in mice, in the dentate gyrus of individuals with a history of child abuse using in situ hybridization. These findings reveal persistent effects of ELS on microglial function and suggest that altered microglial phagocytic capacity is a key contributor to ELS-induced phenotypes.

Prenatal SAMe Treatment Induces Changes in Brain Monoamines and in the Expression of Genes Related to Monoamine Metabolism in a Mouse Model of Social Hierarchy and Depression, Probably via an Epigenetic Mechanism

Reduction in the levels of monoamines, such as serotonin and dopamine in the brain, were reported in patients and animals with depression. SAMe, a universal methyl donor and an epigenetic modulator, is successfully used as an adjunct treatment of depression. We previously found that prenatal treatment with SAMe of Submissive (Sub) mice that serve as a model for depression alleviated many of the behavioral depressive symptoms. In the present study, we treated pregnant Sub mice with 20 mg/kg of SAMe on days 12–15 of gestation and studied the levels of monoamines and the expression of genes related to monoamines metabolism in their prefrontal cortex (PFC) at the age of 3 months. The data were compared to normal saline-treated Sub mice that exhibit depressive-like symptoms. SAMe increased the levels of serotonin in the PFC of female Sub mice but not in males. The levels of 5-HIAA were not changed. SAMe increased the levels of dopamine and of DOPAC in males and females but increased the levels of HVA only in females. The levels of norepinephrine and its metabolite MHPG were unchanged. SAMe treatment changed the expression of several genes involved in the metabolism of these monoamines, also in a sex-related manner. The increase in several monoamines induced by SAMe in the PFC may explain the alleviation of depressive-like symptoms. Moreover, these changes in gene expression more than 3 months after treatment probably reflect the beneficial effects of SAMe as an epigenetic modulator in the treatment of depression.

Immunoinflammatory processes: Overlapping mechanisms between obesity and eating disorders?

Obesity and eating disorders are conditions that involve eating behaviors and are sometimes comorbid. Current evidence supports alterations in immunoinflammatory processes in both obesity and eating disorders. A plausible hypothesis is that immunoinflammatory processes may be involved in the pathophysiology of obesity and eating disorders. The aim of this review is to highlight the link between obesity and eating disorders, with a particular focus on immunoinflammatory processes. First, the relation between obesity and eating disorders will be presented, followed by a brief review of the literature on their association with immunoinflammatory processes. Second, developmental factors will be discussed to clarify the link between obesity, eating disorders, and immunoinflammatory processes. Genetic and epigenetic risk factors as well as the potential roles of stress pathways and early life development will be presented. Finally, implications of these findings for future research are discussed. This review highlighted biological and developmental aspects that overlap between obesity and EDs, emphasizing the need for biopsychosocial research approaches to advance current knowledge and practice in these fields.

Children’s ADHD and Dysregulation Problems, DAT1 Genotype and Methylation, and their Interplay with Family Environment

Background

International literature has underlined the complex interplay between genetic and environmental variables in shaping children’s emotional-behavioral functioning.

Objective

This study aimed to explore the dynamic relationship between children’s Dopamine Transporter (DAT1) genotype and methylation, and maternal and paternal affective environment, on children’s Attention Deficit Hyperactivity Disorder (ADHD) problems and dysregulation problems.

Method

In a community sample of 76 families with school-aged children, we assessed children’s DAT1 genotype and methylation, their own ADHD problems and dysregulation profile (CBCL 6–18 DP), and maternal and paternal psychopathological risk, parenting stress, and marital adjustment. Hierarchical regressions were carried out to verify the possible moderation of children’s genotype on the relationship between children’s methylation and psychopathological risk, parental environment and children’s methylation, and parental environment and children’s psychopathological risk.

Results

The levels of methylation at M1 CpG significantly predicted ADHD problems among children with 10/10 genotype, whereas high levels of methylation at M6 CpG predicted low ADHD problems for children with 9/x genotype. High levels of methylation at M3 CpG were associated with high scores of CBCL DP. DAT1 genotype moderated the relationship between maternal and paternal variables with children’s methylation and psychopathological risk. The scores of maternal and paternal Dyadic Adjustment Scale showed indirect effects on children’s methylation and psychopathological risk in relation to those exerted by risk factors.

Conclusion

Our study has supported the emerging evidence on the complex nature of children’s emotional-behavioral functioning and the associated risk and protective factors, with important implications for the planning of preventive programs.

Association of Maternal Depressive Symptoms During the Perinatal Period With Oppositional Defiant Disorder in Children and Adolescents

IMPORTANCE

An association between perinatal maternal depression and risk of oppositional defiant disorder (ODD) in offspring has not been established. Identifying early determinants of ODD can help inform preventative intervention efforts.

OBJECTIVE

To investigate the association between maternal perinatal depressive symptoms and the risk of ODD in offspring aged 7 to 15 years.

DESIGN, SETTING, AND PARTICIPANTS

This population-based longitudinal birth cohort study used data from the Avon Longitudinal Study of Parents and Children (ALSPAC), in Bristol, UK. All pregnant women residents in Avon, UK, with expected delivery dates from April 1, 1991, to December 31, 1992, were invited to participate in the study. The study cohort ranged from approximately 8000 (at 7 years of age) to 4000 (at 15 years of age) mother-offspring pairs. Data were analyzed from November 2020 to July 2021.

MAIN OUTCOMES AND MEASURES

Maternal depressive symptoms were measured using the Edinburgh Postnatal Depression Scale (EPDS) antenatally at 18 and 32 weeks of gestation and postnatally at 8 weeks and 8 months. This study primarily used a cutoff score of 12 or more on the EPDS to identify mothers with symptoms of depression, and the continuous EPDS scores were used to confirm the results of the main analyses. Offspring ODD at 7, 10, 13, and 15 years of age were diagnosed using the parent-reported Development and Well-Being Assessment.

RESULTS

Of 7994 mother-offspring pairs for whom data were available on offspring ODD at 7 years, 4102 offspring (51.3%) were boys. The mean (SD) age of mothers was 28.6 (4.6) years. Maternal antenatal depressive symptoms (measured at 32 weeks of gestation) were associated with offspring ODD (adjusted odds ratio [AOR], 1.75; 95% CI, 1.33-2.31). Offspring of mothers with postpartum depressive symptoms at 8 weeks and 8 months were more than 2 times more likely to have a diagnosis of ODD over time (AOR at 8 weeks, 2.24 [95% CI, 1.74-2.90]; AOR at 8 months, 2.04 [95% CI, 1.55-2.68]), and maternal persistent depressive symptoms were associated with a 4-fold increased risk of offspring ODD (AOR, 3.59; 95% CI, 1.98-6.52).

CONCLUSIONS AND RELEVANCE

These findings suggest that perinatal depressive symptoms are associated with ODD in offspring and further support the need for early identification and management of prenatal and postnatal depression in women of childbearing age.

Early Life Stress and Metabolic Plasticity of Brain Cells: Impact on Neurogenesis and Angiogenesis

Early life stress (ELS) causes long-lasting changes in brain plasticity induced by the exposure to stress factors acting prenatally or in the early postnatal ontogenesis due to hyperactivation of hypothalamic-pituitary-adrenal axis and sympathetic nervous system, development of neuroinflammation, aberrant neurogenesis and angiogenesis, and significant alterations in brain metabolism that lead to neurological deficits and higher susceptibility to development of brain disorders later in the life. As a key component of complex pathogenesis, ELS-mediated changes in brain metabolism associate with development of mitochondrial dysfunction, loss of appropriate mitochondria quality control and mitochondrial dynamics, deregulation of metabolic reprogramming. These mechanisms are particularly critical for maintaining the pool and development of brain cells within neurogenic and angiogenic niches. In this review, we focus on brain mitochondria and energy metabolism related to tightly coupled neurogenic and angiogenic events in healthy and ELS-affected brain, and new opportunities to develop efficient therapeutic strategies aimed to restore brain metabolism and reduce ELS-induced impairments of brain plasticity.

Psychological Traumas and Cardiovascular Disease: A Case-Control Study

Adverse childhood experiences could be important determinants of adult disease. The present study analyzed the association between early traumatic experiences and the onset of cardiovascular disease (CVDs). It was hypothesized that patients with CVD would report a higher number of traumatic experiences during childhood and that this association would be stronger in women. The Traumatic Experiences Checklist (TEC) was fulfilled by 75 patients with a first-time diagnosis of CVD and 84 healthy controls randomly selected from the general population. The two groups were not balanced for age and sex. Multivariate analyses of covariance (MANCOVAs) and analyses of covariance (ANCOVAs), with group (clinical vs. control) and gender (male vs. female) as between-subjects factors, and age of participants as covariate, were performed on the number and the impact of the traumatic experiences (emotional neglect, emotional abuse, physical abuse, sexual harassment, and sexual abuse) for the three age group in which the trauma was experienced (from 0 to 10, from 11 to 18, from 19 years onwards). The main results showed that participants with CVDs have experienced a higher number of early traumatic experiences compared to the control group, such as emotional neglect (p = 0.023), emotional abuse (0.008 ≤ p ≤ 0.033), and physical abuse (0.001 < p ≤ 0.038). The results also revealed that women with CVDs have experienced more traumatic events compared to the women of the control group (0.001 < p ≤ 0.020). These results seem to highlight an association between traumatic experiences in childhood and CVD in adulthood, particularly in women. Such findings could have relevant implications for clinical practice, suggesting the importance of adopting an integrated approach in the care of the patient with cardiovascular diseases paying attention also to the clinical psychological risk factors.

Pivotal mental states

This paper introduces a new construct, the 'pivotal mental state', which is defined as a hyper-plastic state aiding rapid and deep learning that can mediate psychological transformation. We believe this new construct bears relevance to a broad range of psychological and psychiatric phenomena. We argue that pivotal mental states serve an important evolutionary function, that is, to aid psychological transformation when actual or perceived environmental pressures demand this. We cite evidence that chronic stress and neurotic traits are primers for a pivotal mental state, whereas acute stress can be a trigger. Inspired by research with serotonin 2A receptor agonist psychedelics, we highlight how activity at this particular receptor can robustly and reliably induce pivotal mental states, but we argue that the capacity for pivotal mental states is an inherent property of the human brain itself. Moreover, we hypothesize that serotonergic psychedelics hijack a system that has evolved to mediate rapid and deep learning when its need is sensed. We cite a breadth of evidences linking stress via a variety of inducers, with an upregulated serotonin 2A receptor system (e.g. upregulated availability of and/or binding to the receptor) and acute stress with 5-HT release, which we argue can activate this primed system to induce a pivotal mental state. The pivotal mental state model is multi-level, linking a specific molecular gateway (increased serotonin 2A receptor signaling) with the inception of a hyper-plastic brain and mind state, enhanced rate of associative learning and the potential mediation of a psychological transformation.

Prenatal maternal distress and immune cell epigenetic profiles at 3-months of age

BACKGROUND

Prenatal maternal distress predicts altered offspring immune outcomes, potentially via altered epigenetics. The role of different kinds of prenatal maternal distress on DNA methylation profiles is not understood.

METHODS

A sample of 117 women (APrON cohort) were followed from pregnancy to the postpartum period. Maternal distress (depressive symptoms, pregnancy-specific anxiety, stressful life events) were assessed mid-pregnancy, late-pregnancy, and 3-months postpartum. DNA methylation profiles were obtained from 3-month-old blood samples. Principal component analysis identified two epigenetic components, characterized as Immune Signaling and DNA Transcription through gene network analysis. Covariates were maternal demographics, pre-pregnancy body mass index, child sex, birth gestational age, and postpartum maternal distress. Penalized regression (LASSO) models were used.

RESULTS

Late-pregnancy stressful life events, b = 0.006, early-pregnancy depressive symptoms, b = 0.027, late-pregnancy depressive symptoms, b = 0.014, and pregnancy-specific anxiety during late pregnancy, b = -0.631, were predictive of the Immune Signaling component, suggesting that these aspects of maternal distress could affect methylation in offspring immune signaling pathways. Only early-pregnancy depressive symptoms was predictive of the DNA Transcription component, b = -0.0004, suggesting that this aspect of maternal distress is implicated in methylation of offspring DNA transcription pathways.

CONCLUSIONS

Exposure timing and kind of prenatal maternal distress could matter in the prediction of infant immune epigenetic profiles.

The Methylation of Clock Genes in Perinatal Depression: Which Role for Oxytocin?

Background: Perinatal Depression (PD) is a widespread disabling condition that is hypothesized to be associated with abnormalities in circadian rhythms and neuropeptide release including oxytocin (OXT). Methods: Fourty-four pregnant women (28 with PD, and 16 controls) were evaluated through the Edinburgh Postnatal Depression Scale (EPDS), the State/Trait Anxiety Inventory Form Y (STAI-Y), and the Prenatal Attachment Inventory (PAI). A blood sample was collected from all participants, and OXT plasma levels, DNA methylation of clock genes, as well as of FOXp3 and HERV-W were measured. Linear regression analyses were performed to assess the effect of oxytocin on the methylation of selected genes. Continuous ordinal regression models was further applied to see if the score of rating scales was associated to gene methylation, adjusting for oxytocin-methylation interaction. Results: OXT plasma levels were positively associated with CRY1 methylation. Women with higher OXT plasma levels showed an association between higher degree of CRY2 methylation (thus, reduced expression) and lower EPDS (OR = 0.21; P = 0.043) and STAI-S scores (OR = 6.96; P = 0.019). Finally, with high OXT levels, hypermethylation of CRY1 was associated to higher scores on the PAI (OR = 2.74; P = 0.029) while higher methylation of HERV-W related to lower PAI scores (OR = 0.273; P = 0.019). Conclusion: Our results suggest a possible protective role played by oxytocin in the development of PD by promoting a favorable methylation profile characterized by reduced expression of CRY1 and CRY2. Moreover, oxytocin strengthens the association between maternal prenatal attachment with a favorable pattern of methylation of clock genes and HERV-W, which is essential for pregnancy outcomes.

Environmental enrichment enhances sociability by regulating glutamate signaling pathway through GR by epigenetic mechanisms in amygdala of Indian field mice Mus booduga

Environmental enrichment (EE) dynamically regulates gene expression and synaptic plasticity with positive consequences on behavior. The present study was performed on field-mice to explore the effects of EE on both captive-condition inducing social stress and epigenetic changes of molecules resilience stress. For this purpose, field-mice were caught and allowed to habituate in standard laboratory conditions for 7 days. The next day animals were randomly assigned to three groups: i) mice at short-term standard condition (STSC); which were subjected to social interaction test (SIT) on day 9, ii) mice continuously maintainedfor additional 30 days, with these long-term standard conditions (LTSC), and iii) mice maintained in an EE cage for additional 30 days. After achieving SIT, we examined epigenetic changes of a repertory of molecules associated with resilience stress, by determining their levels by Western blot. Thus, the main findings were that during SIT, EE exerted more social interaction of field-mice with the strangers compared with STSC and LTSC mice. Related with social behavior results, we found that in mice subjected to EE the levels of histone 3 lysine 9 di-methylation (H3K9me2), glucocorticoid receptor (GR), N-methyl-D asparate (NMDA) receptor subunits NR2A and NR2B, postsynaptic density protein-95 (PSD-95), and mature brain-derived neurotrophic factor (mBDNF) were significantly elevated; whereas the levels of DNA methyltransferase-3A (DNMT3A), methyl-CpG-binding protein-2 (MeCP2), repressor element-1 silencing transcription factor (REST), H3K4me2 and lysine demethylase-1A (KDM1A) decreased. These results suggest that enhanced sociability of EE mice could be mediated, in part, by altered expression of molecules regulating glutamate signaling pathway through GR by epigenetic mechanisms.

Food Addiction and Psychosocial Adversity: Biological Embedding, Contextual Factors, and Public Health Implications

The role of stress, trauma, and adversity particularly early in life has been identified as a contributing factor in both drug and food addictions. While links between traumatic stress and substance use disorders are well documented, the pathways to food addiction and obesity are less established. This review focuses on psychosocial and neurobiological factors that may increase risk for addiction-like behaviors and ultimately increase BMI over the lifespan. Early childhood and adolescent adversity can induce long-lasting alterations in the glucocorticoid and dopamine systems that lead to increased addiction vulnerability later in life. Allostatic load, the hypothalamic-pituitary-adrenal axis, and emerging data on epigenetics in the context of biological embedding are highlighted. A conceptual model for food addiction is proposed, which integrates data on the biological embedding of adversity as well as upstream psychological, social, and environmental factors. Dietary restraint as a feature of disordered eating is discussed as an important contextual factor related to food addiction. Discussion of various public health and policy considerations are based on the concept that improved knowledge of biopsychosocial mechanisms contributing to food addiction may decrease stigma associated with obesity and disordered eating behavior.

Low Oxygen Stress During Early Development Influences Regulation of Hypoxia-Response Genes in Farmed Atlantic Salmon (Salmo salar)

Survival and growth of developing salmonids are negatively affected by low oxygen levels within gravel nests in natural streams, and hypoxic stress is often experienced by farmed Atlantic salmon (Salmo salar) within hatcheries. Exposure to hypoxia during early development may have long-lasting effects by altering epigenetic marks and gene expression in oxygen regulatory pathways. Here, we examine the transcriptomic response to low dissolved oxygen (DO) in post-hatch salmon reared continuously in 30%, 60% or 100% DO from fertilization until start of feeding. RNA sequencing revealed multiple differentially expressed genes, including oxygen transporting hemoglobin embryonic α subunit (hbae) and EGLN3 family hypoxia-inducible factor 3 (egln3) which regulates the stability of hypoxia inducible factor 1α (HIF-1α). Both hbae and egln3 displayed expression levels inversely correlated to oxygen concentration, and DNA methylation patterns within the egln3 promoter were negatively associated with the transcript levels. These results suggest that epigenetic processes are influenced by low oxygen levels during early development in Atlantic salmon to upregulate hypoxia-response genes.

Eating Disorders, Heredity and Environmental Activation: Getting Epigenetic Concepts into Practice

Epigenetic mechanisms are believed to link environmental exposures to alterations in gene expression, and in so doing, to provide a physical substrate for the activation of hereditary potentials by life experiences. In keeping with this idea, accumulating data suggest that epigenetic processes are implicated in eating-disorder (ED) etiology. This paper reviews literature on putative links between epigenetic factors and EDs, and examines ways in which epigenetic programming of gene expression could account for gene-environment interactions acting in the EDs. The paper also presents evidence suggesting that epigenetic processes link malnutrition and life stresses (gestational, perinatal, childhood, and adult) to risk of ED development. Drawing from empirical evidence and clinical experience, we propose that an epigenetically informed understanding of ED etiology can benefit patients, caregivers, and clinicians alike, in the sense that the perspective can reduce judgmental or blameful attitudes on the part of clinicians and caregivers, and increase self-acceptance and optimism about recovery on the part of those affected.

Epigenetic signatures of attachment insecurity and childhood adversity provide evidence for role transition in the pathogenesis of perinatal depression

Early life adversity and insecure attachment style are known risk factors for perinatal depression. The biological pathways linking these experiences, however, have not yet been elucidated. We hypothesized that overlap in patterns of DNA methylation in association with each of these phenomena could identify genes and pathways of importance. Specifically, we wished to distinguish between allostatic-load and role-transition hypotheses of perinatal depression. We conducted a large-scale analysis of methylation patterns across 5 × 106 individual CG dinucleotides in 54 women participating in a longitudinal prospective study of perinatal depression, using clustering-based criteria for significance to control for multiple comparisons. We identified 1580 regions in which methylation density was associated with childhood adversity, 3 in which methylation density was associated with insecure attachment style, and 6 in which methylation density was associated with perinatal depression. Shorter telomeres were observed in association with childhood trauma but not with perinatal depression or attachment insecurity. A detailed analysis of methylation density in the oxytocin receptor gene revealed similar patterns of DNA methylation in association with perinatal depression and with insecure attachment style, while childhood trauma was associated with a distinct methylation pattern in this gene. Clinically, attachment style was strongly associated with depression only in pregnancy and the early postpartum, whereas the association of childhood adversity with depression was time-invariant. We concluded that the broad DNA methylation signature and reduced telomere length associated with childhood adversity could indicate increased allostatic load across multiple body systems, whereas perinatal depression and attachment insecurity may be narrower phenotypes with more limited DNA methylation signatures outside the CNS, and no apparent association with telomere length or, by extension, allostatic load. In contrast, the finding of matching DNA methylation patterns within the oxytocin receptor gene for perinatal depression and attachment insecurity is consistent with the theory that the perinatal period is a time of activation of existing attachment schemas for the purpose of structuring the mother-child relationship, and that such activation may occur in part through specific patterns of methylation of the oxytocin receptor gene.

The Methylation Patterns and Transcriptional Responses to Chilling Stress at the Seedling Stage in Rice

Chilling stress is considered the major abiotic stress affecting the growth, development, and yield of rice. To understand the transcriptomic responses and methylation regulation of rice in response to chilling stress, we analyzed a cold-tolerant variety of rice (Oryza sativa L. cv. P427). The physiological properties, transcriptome, and methylation of cold-tolerant P427 seedlings under low-temperature stress (2–3 °C) were investigated. We found that P427 exhibited enhanced tolerance to low temperature, likely via increasing antioxidant enzyme activity and promoting the accumulation of abscisic acid (ABA). The Methylated DNA Immunoprecipitation Sequencing (MeDIP-seq) data showed that the number of methylation-altered genes was highest in P427 (5496) and slightly lower in Nipponbare (Nip) and 9311 (4528 and 3341, respectively), and only 2.7% (292) of methylation genes were detected as common differentially methylated genes (DMGs) related to cold tolerance in the three varieties. Transcriptome analyses revealed that 1654 genes had specifically altered expression in P427 under cold stress. These genes mainly belonged to transcription factor families, such as Myeloblastosis (MYB), APETALA2/ethylene-responsive element binding proteins (AP2-EREBP), NAM-ATAF-CUC (NAC) and WRKY. Fifty-one genes showed simultaneous methylation and expression level changes. Quantitative RT-PCR (qRT-PCR) results showed that genes involved in the ICE (inducer of CBF expression)-CBF (C-repeat binding factor)—COR (cold-regulated) pathway were highly expressed under cold stress, including the WRKY genes. The homologous gene Os03g0610900 of the open stomatal 1 (OST1) in rice was obtained by evolutionary tree analysis. Methylation in Os03g0610900 gene promoter region decreased, and the expression level of Os03g0610900 increased, suggesting that cold stress may lead to demethylation and increased gene expression of Os03g0610900. The ICE-CBF-COR pathway plays a vital role in the cold tolerance of the rice cultivar P427. Overall, this study demonstrates the differences in methylation and gene expression levels of P427 in response to low-temperature stress, providing a foundation for further investigations of the relationship between environmental stress, DNA methylation, and gene expression in rice.

Altered amygdala DNA methylation mechanisms after adolescent alcohol exposure contribute to adult anxiety and alcohol drinking

Binge drinking during adolescence increases the risk for neuropsychiatric disorders including alcoholism in adulthood. DNA methylation in post-mitotic neurons is an important epigenetic modification that plays a crucial role in neurodevelopment. We examined the effects of intermittent ethanol exposure during adolescence on adult behavior and whether DNA methylation changes provide a plausible explanation for the lasting effects of this developmental insult. One hour after last adolescent intermittent ethanol (AIE), growth arrest and DNA damage inducible protein 45 (Gadd45a, Gadd45b, and Gadd45g) mRNA expression was increased and DNA methyltransferase (DNMT) activity and Dnmt3b expression was decreased in the amygdala as compared to adolescent intermittent saline (AIS) rats. However, AIE rats 24 h after last exposure displayed increased DNMT activity but normalized Gadd45 and Dnmt3b mRNA expression compared to AIS rats. In adulthood, rats exposed to AIE show increased Dnmt3b mRNA expression and DNMT activity, along with decreased Gadd45g mRNA expression in the amygdala. DNA methylation of neuropeptide Y (Npy) and brain-derived neurotrophic factor (Bdnf) exon IV is increased in the AIE adult amygdala compared to AIS adult rats. Treatment with the DNMT inhibitor 5-azacytidine (5-azaC) at adulthood normalizes the AIE-induced DNA hypermethylation of Npy and Bdnf exon IV with concomitant reversal of AIE-induced anxiety-like and alcohol-drinking behaviors. These results suggest that binge-like ethanol exposure during adolescence leads to dysregulation in DNA methylation mechanisms in the amygdala which may contribute to behavioral phenotypes of anxiety and alcohol use in adulthood.

Does epigenetic 'memory' of early-life stress predispose to chronic pain in later life? A potential role for the stress regulator FKBP5

Animal behaviours are affected not only by inherited genes but also by environmental experiences. For example, in both rats and humans, stressful early-life events such as being reared by an inattentive mother can leave a lasting trace and affect later stress response in adult life. This is owing to a chemical trace left on the chromatin attributed to so-called epigenetic mechanisms. Such an epigenetic trace often has consequences, sometimes long-lasting, on the functioning of our genes, thereby allowing individuals to rapidly adapt to a new environment. One gene under such epigenetic control is FKBP5, the gene that encodes the protein FKPB51, a crucial regulator of the stress axis and a significant driver of chronic pain states. In this article, we will discuss the possibility that exposure to stress could drive the susceptibly to chronic pain via epigenetic modifications of genes within the stress axis such as FKBP5. The possibility that such modifications, and therefore, the susceptibility to chronic pain, could be transmitted across generations in mammals and whether such mechanisms may be evolutionarily conserved across phyla will also be debated. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.

Early-life adversity-induced long-term epigenetic programming associated with early onset of chronic physical aggression: Studies in humans and animals

Objectives: To examine whether chronic physical aggression (CPA) in adulthood can be epigenetically programmed early in life due to exposure to early-life adversity. Methods: Literature search of public databases such as PubMed/MEDLINE and Scopus. Results: Children/adolescents susceptible for CPA and exposed to early-life abuse fail to efficiently cope with stress that in turn results in the development of CPA later in life. This phenomenon was observed in humans and animal models of aggression. The susceptibility to aggression is a complex trait that is regulated by the interaction between environmental and genetic factors. Epigenetic mechanisms mediate this interaction. Subjects exposed to stress early in life exhibited long-term epigenetic programming that can influence their behaviour in adulthood. This programming affects expression of many genes not only in the brain but also in other systems such as neuroendocrine and immune. Conclusions: The propensity to adult CPA behaviour in subjects experienced to early-life adversity is mediated by epigenetic programming that involves long-term systemic epigenetic alterations in a whole genome.

Effects of early social deprivation on epigenetic statuses and adaptive behavior of young children: A study based on a cohort of institutionalized infants and toddlers

Early social deprivation (i.e., an insufficiency or lack of parental care) has been identified as a significant adverse early experience that may affect multiple facets of child development and cause long-term outcomes in physical and mental health, cognition and behavior. Current research provides growing evidence that epigenetic reprogramming may be a mechanism modulating these effects of early adversities. This work aimed to investigate the impact of early institutionalization—the immersion in an extreme socially depriving environment in humans—on the epigenome and adaptive behavior of young children up to 4 years of age. We conducted a cross-sectional study involving two comparison groups: 29 children raised in orphanages and 29 children raised in biological families. Genome-wide DNA methylation profiles of blood cells were obtained using the Illumina MethylationEPIC array; the level of child adaptive functioning was assessed using the Vineland Adaptive Behavior Scales-II. In comparison to children raised in families, children residing in orphanages had both statistically significant deficits in multiple adaptive behavior domains and statistically significant differences in DNA methylation states. Moreover, some of these methylation states may directly modulate the behavioral deficits; according to preliminary estimates, about 7–14% of the deviation of adaptive behavior between groups of children may be determined by their difference in DNA methylation profiles. The duration of institutionalization had a significant impact on both the adaptive level and DNA methylation status of institutionalized children.

Written in the Body?: Healing the Epigenetic Molecular Wounds of Complex Trauma Through Empathy and Kindness

While research on the biological/genetic approach to trauma transmission has become increasingly abundant over the past 15 years, this research has been primarily limited to scientific research journals and has not yet significantly appeared in practice journals, graduate programs, clinical settings, or policy decisions. This paper aims to develop a bridge across disciplines, integrating a review of biological science literature with mental health literature to provide a multidisciplinary overview of the role of epigenetic mechanisms in the transmission of complex trauma. Such a multidisciplinary overview is important in allowing professionals across disciplines to approach their work with a more complete understanding of the way in which ecological systems shape trauma transmission and healing. While encouraging collaboration between researchers and providers across fields, this paper argues that to heal the person, one must first work to heal the environment.

Assessing Panic: Bridging the Gap Between Fundamental Mechanisms and Daily Life Experience

Panic disorder (PD) is one of the most common psychiatric disorders. Recurrent, unexpected panic attacks (PAs) are the primary symptom and strongly impact patients’ quality of life. Clinical manifestations are very heterogeneous between patients, emphasizing the need for a dimensional classification integrating various aspects of neurobiological and psychological circuits in line with the Research Domain Criteria (RDoC) proposed by the US National Institute of Mental Health. To go beyond data that can be collected in the daily clinical situation, experimental panic provocation is widely used, which has led to important insights into involved brain regions and systems. Genetic variants can determine the sensitivity to experimental models such as carbon dioxide (CO₂) exposure and can increase the risk to develop PD. Recent developments now allow to better assess the dynamic course of PAs outside the laboratory in patients’ natural environment. This can provide novel insights into the underlying mechanisms and the influence of environmental factors that can alter gene regulation by changing DNA methylation. In this mini review, we discuss assessment of PAs in the clinic, in the laboratory using CO₂ exposure, genetic associations, and the benefits of real-life assessment and epigenetic research.

The influence of aging on the methylation status of brain-derived neurotrophic factor gene in blood

OBJECTIVE

Brain-derived neurotrophic factor (BDNF) is involved in the pathophysiology of psychiatric disorders in adults and elderly individuals, and as a result, the DNA methylation (DNAm) of the BDNF gene in peripheral tissues including blood has been extensively examined to develop a useful biomarker for psychiatric disorders. However, studies to date have not previously investigated the effect of age on DNAm of the BDNF gene in blood. In this context, we measured DNAm of 39 CpG units in the CpG island at the promoter of exon I of the BDNF gene.

METHODS

We analyzed genomic DNA from peripheral blood of 105 health Japanese women 20 to 80 years of age to identify aging-associated change in DNAm of the BDNF gene. In addition, we examined the relationship between total MMSE scores, numbers of stressful life events, and serum BDNF levels on DNAm of the BDNF gene. The DNAm rate at each CpG unit was measured using a MassArray^® system (Agena Bioscience), and serum BDNF levels were measured by ELISA.

RESULTS

There was a significant correlation between DNAm and age in 13 CpGs. However, there was no significant correlation between DNAm and total MMSE scores, numbers of life events, or serum BDNF levels.

CONCLUSION

Despite the small number of subjects and the inclusion of only female subjects, our results suggest that DNAm of 13 CpGs of the BDNF gene may be an appropriate biomarker for aging and useful for predicting increased susceptibility to age-related psychiatric disorders.

Long-Lasting Effects of Prenatal Ethanol Exposure on Fear Learning and Development of the Amygdala

Prenatal ethanol exposure (PrEE) produces developmental abnormalities in brain and behavior that often persist into adulthood. We have previously reported abnormal cortical gene expression, disorganized neural circuitry along with deficits in sensorimotor function and anxiety in our CD-1 murine model of fetal alcohol spectrum disorders, or FASD (El Shawa et al., 2013; Abbott et al., 2016). We have proposed that these phenotypes may underlie learning, memory, and behavioral deficits in humans with FASD. Here, we evaluate the impact of PrEE on fear memory learning, recall and amygdala development at two adult timepoints. PrEE alters learning and memory of aversive stimuli; specifically, PrEE mice, fear conditioned at postnatal day (P) 50, showed deficits in fear acquisition and memory retrieval when tested at P52 and later at P70–P72. Interestingly, this deficit in fear acquisition observed during young adulthood was not present when PrEE mice were conditioned later, at P80. These mice displayed similar levels of fear expression as controls when tested on fear memory recall. To test whether PrEE alters development of brain circuitry associated with fear conditioning and fear memory recall, we histologically examined subdivisions of the amygdala in PrEE and control mice and found long-term effects of PrEE on fear memory circuitry. Thus, results from this study will provide insight on the neurobiological and behavioral effects of PrEE and provide new information on developmental trajectories of brain dysfunction in people prenatally exposed to ethanol.

Early-Life Adversity Induces Epigenetically Regulated Changes in Hippocampal Dopaminergic Molecular Pathways

Early-life adversity (ELA) represents a major risk factor for the development of behavioral dysfunctions and mental disorders later in life. On the other hand, dependent on type, time point, and duration, ELA exposure can also induce adaptations, which result in better stress coping and resilience later in life. Guided by the hypothesis that chronic exposure to ELA results in dysfunctional brain and behavior, whereas short exposure to ELA may result in resilience, the behavioral and neurobiological consequences of long-term separation stress (LTSS) and short-term separation stress (STSS) were compared in a mouse model for ELA. In line with our hypothesis, we found that LTSS induced depressive-like behavior, whereas STSS reduced depressive-like behavioral symptoms. We then tested the hypothesis that the opposite behavioral outcomes of the two stress paradigms may be mediated by functional, epigenetically regulated changes of dopaminergic modulation in the hippocampal formation. We found that STSS exposure elevated dopamine receptor D1 (DRD1) gene expression and decreased gene expression of its downstream modulator DARPP-32 (32-kDa dopamine- and cAMP-regulated phosphoprotein), which was paralleled by decreased H3 acetylation at its gene promoter region. In contrast, LTSS elevated DARPP-32 gene expression, which was not paralleled by changes in histone acetylation and DRD1 gene expression. These findings indicate that short- and long-term neonatal exposure to ELA induces changes in dopaminergic molecular pathways, some of which are epigenetically regulated and which either alleviate or aggravate depressive-like symptoms later in life.

Sex-specific epigenetic mediators between early life social disadvantage and adulthood BMI

AIM

The objective of this study was to identify potential epigenetic mediating pathways linking early life social disadvantage (ELSD) to adulthood BMI.

METHODS

Sex-specific epigenome-wide two-stage mediation analyses were conducted in blood and adipose tissue, and mediation estimates were obtained using cross-product mediation analysis. Pathway analyses were conducted using GREAT software (Bejerano Lab, CA, USA).

RESULTS

Candidate mediation CpG sites were identified in adipose tissue, but not blood, and were sex-specific. Significant mediation sites in females included CpG loci in genes: PKHG1, BCAR3, ADAM5P, PIEZO1, FGFRL1, FASN and DPP9, among others. Pathway analyses revealed evidence of enrichment for processes associated with TFG-β signaling and immunologic signatures. In males, significant mediation loci included sites in MAP3K5 and RPTOR, which have previously been associated with adipogenesis, inflammation and insulin resistance.

CONCLUSION

Our findings provide supportive evidence for the mediating role of epigenetic mechanisms in the effect of early life social disadvantage on adulthood BMI.

Stress exposure and psychopathology alter methylation of the serotonin receptor 2A (HTR2A) gene in preschoolers

Serotonin signaling pathways play a key role in brain development, stress reactivity, and mental health. Epigenetic alterations in the serotonin system may underlie the effect of early life stress on psychopathology. The current study examined methylation of the serotonin receptor 2A (HTR2A) gene in a sample of 228 children including 119 with child welfare documentation of moderate to severe maltreatment within the last 6 months. Child protection records, semistructured interviews in the home, and parent reports were used to assess child stress exposure, psychiatric symptoms, and behavior. The HTR2A genotype and methylation of HTR2A were measured at two CpG sites (-1420 and -1224) from saliva DNA. HTR2A genotype was associated with HTR2A methylation at both CpG sites. HTR2A genotype also moderated associations of contextual stress exposure and HTR2A methylation at site -1420. Contextual stress was positively associated with -1420 methylation among A homozygotes, but negatively associated with -1420 methylation among G homozygotes. Posttraumatic stress disorder and major depressive disorder symptoms were negatively associated with methylation at -1420, but positively associated with methylation at -1224. Results support the view that the serotonin system is sensitive to stress exposure and psychopathology, and HTR2A methylation may be a mechanism by which early adversity is biologically encoded.

Genipin normalizes depression-like behavior induced by prenatal stress through inhibiting DNMT1

Synthetic antidepressants in current use for the complex etiopathogeneses of depression have slow response and remission as well as various unpleasant side effects. As a result, it is imperative to develop new antidepressants with more effectiveness and less severe side effects. Recent studies demonstrated that genipin, the aglycon of geniposide, extracted from Gardenia jasminoides Ellis has antidepressive effects. However, knowledge regarding the molecular mechanisms of its antidepressant effects remains limited. Employing a depression-like mouse model, we confirmed that genipin is capable of correcting depressions-like behaviors induced by prenatal stress in offspring from prenatally stressed dams (defined as PRS mice). In further experiments, we found that the effect of genipin on PRS mice occurs through DNA demethylation by inhibiting DNA methyltransferase 1 (DNMT1), normalizing the expression of reduced brain-derived neurotrophic factor (BDNF) in the hippocampus.

Advancing behavioural genomics by considering timescale

Animal behavioural traits often covary with gene expression, pointing towards a genomic constraint on organismal responses to environmental cues. This pattern highlights a gap in our understanding of the time course of environmentally responsive gene expression, and moreover, how these dynamics are regulated. Advances in behavioural genomics explore how gene expression dynamics are correlated with behavioural traits that range from stable to highly labile. We consider the idea that certain genomic regulatory mechanisms may predict the timescale of an environmental effect on behaviour. This temporally minded approach could inform both organismal and evolutionary questions ranging from the remediation of early life social trauma to understanding the evolution of trait plasticity.

The role of DNA methylation in the association between childhood adversity and cardiometabolic disease

Growing evidence suggests that adverse environmental stimuli, especially during sensitive periods in early life, may lead to cardiometabolic disease in later life. However, the underlying biological mechanisms remain a mystery. Recent studies inferred that epigenetic modifications are likely involved. We review recent studies, primarily focused on the findings from human studies, to indicate the role of DNA methylation in the associations between childhood adversity and cardiometabolic disease in adulthood. In particular, we focused on DNA methylation modifications in genes regulating the hypothalamus-pituitary-adrenal axis as well as the immune system.

Depressive Symptom Prevalence and Predictors in the First Half of Pregnancy

INTRODUCTION

Major depression during the peripartum (MDP) period carries significant public health impact due to the potential adverse effects on maternal, infant, and family outcomes.

METHODS

As part of a larger longitudinal study, this cross-sectional observational study sought to build upon the current literature on the prevalence and predictors of depression in the early second trimester of pregnancy, as related to generally accepted risk factors and other less explored risk factors.

RESULTS

The findings from this study suggest that in this sample of 230 black and white women at ∼14 weeks gestation, ∼19% endorsed depressive symptoms and that the most important predictors of depression in pregnancy were a preconception history of a mental health issue (e.g., lifetime depressive episode) and perceived stress. Other relevant predictors were pregnancy-related anxiety, income, and stressful life events.

CONCLUSION/CLINICAL RELEVANCE

It is important for clinicians not only to screen for MDP during prenatal visits by asking about current depressive, stress, and anxiety symptoms but also to identify patients at risk for MDP by asking simple questions about history of preconception/lifetime episodes of depression and stressful life events. Given the variance accounted for by lifetime depression, additional research into how clinicians may approach this important topic is warranted. For example, checklists given in the waiting room may be less likely to elicit endorsement compared with conversations aimed to normalize the range of depressive histories that may have relevance to obstetric health.

Perinatal depression and DNA methylation of oxytocin-related genes: a study of mothers and their children

The present study investigated the association of perinatal depression (PD) with differential methylation of 3 genomic regions among mother and child dyads: exon 3 within the oxytocin receptor (OXTR) gene and 2 intergenic regions (IGR) between the oxytocin (OXT) and vasopressin (AVP) genes. Maternal PD was assessed at 5 time-points during pregnancy and postpartum. Four groups were established based on Edinburgh Postnatal Depression Scale (EPDS) cut-off scores: no PD, prenatal or postpartum depressive symptoms only and persistent PD (depressive symptoms both prenatally and postpartum). Salivary DNA was collected from mothers and children at the final time-point, 2.9years postpartum. Mothers with persistent PD had significantly higher overall OXTR methylation than the other groups and this pattern extended to 16/22 individual CpG sites. For the IGR, only the region closer to the AVP gene (AVP IGR) showed significant differential methylation, with the persistent PD group displaying the lowest levels of methylation overall, but not for individual CpG sites. These results suggest that transient episodes of depression may not be associated with OXTR hypermethylation. Validation studies need to confirm the downstream biological effects of AVP IGR hypomethylation as it relates to persistent PD. Differential methylation of the OXTR and IGR regions was not observed among children exposed to maternal PD. The consequences of OXTR hypermethylation and AVP IGR hypomethylation found in mothers with persistent PDS may not only impact the OXT system, but may also compromise maternal behavior, potentially resulting in negative outcomes for the developing child.

Impacts of Early Life Stress on the Methylome and Transcriptome of Atlantic Salmon

Exposure to environmental stressors during early-life stages can change the rate and timing of various developmental processes. Epigenetic marks affecting transcriptional regulation can be altered by such environmental stimuli. To assess how stress might affect the methylome and transcriptome in salmon, fish were treated using cold-shock and air-exposure from the eye-stage until start-feeding. The fish were either stressed prior to hatching (E), post-hatching (PH), pre- and post-hatching (EPH) or not stressed (CO). Assessing transcriptional abundances just prior to start feeding, E and PH individuals were found to have modified the expression of thousands of genes, many with important functions in developmental processes. The EPH individuals however, showed expression similar to those of CO, suggesting an adaptive response to extended periods of stress. The methylome of stressed individuals differed from that of the CO, suggesting the importance of environment in shaping methylation signatures. Through integration of methylation with transcription, we identified bases with potential regulatory functions, some 10s of kb away from the targeted genes. We then followed fish growth for an additional year. Individuals in EPH showed superior growth compared to other treatment groups, highlighting how stress can potentially have long-lasting effects on an organism's ability to adapt to environmental perturbations.

Effects of Dim Light at Night on Food Intake and Body Mass in Developing Mice

Appropriately timed light is critical for circadian organization; exposure to dim light at night (dLAN) disrupts temporal organization of endogenous biological timing. Exposure to dLAN in adult mice is associated with elevated body mass and changes in metabolism putatively driven by voluntary changes in the time of food intake. We predicted that exposure of young mice to LAN could affect adult metabolic function. At 3 weeks (Experiment 1) or 5 weeks (Experiment 2) of age, mice were either maintained in standard light-dark (DARK) cycles or exposed to nightly dLAN (5 lux). In the first two experiments, food intake and locomotor activity were assessed after 4 weeks and a glucose tolerance test was administered after 6 weeks in experimental lighting conditions. In Experiment 3, tissues were collected around the clock at 6 h intervals to investigate rhythmic hepatic clock gene expression in mice exposed to dLAN from 3 or 5 weeks of age. Male and female mice exposed to dLAN beginning at 3 weeks of age displayed similar growth rates and body mass to DARK-reared offspring, despite increasing day-time food intake. Exposure to dLAN beginning at 5 weeks of age increased body mass and daytime food intake in male, but not female, mice. Consistent with the body mass phenotype, clock gene expression was unaltered in the liver. In contrast to adults, dLAN exposure during the development of the peripheral circadian system has sex- and development-dependent effects on body mass gain.