The epigenetics of social adversity in early life: implications for mental health outcomes

Ribosomal DNA transcription in the dorsal raphe nucleus is increased in residual but not in paranoid schizophrenia

The central serotonergic system is implicated in the pathogenesis of schizophrenia, where the imbalance between dopamine, serotonin and glutamate plays a key pathophysiological role. The dorsal raphe nucleus (DRN) is the main source of serotonergic innervation of forebrain limbic structures disturbed in schizophrenia patients. The study was carried out on paraffin-embedded brains from 17 (8 paranoid and 9 residual) schizophrenia patients and 28 matched controls without mental disorders. The transcriptional activity of ribosomal DNA (rDNA) in DRN neurons was evaluated by the AgNOR silver-staining method. An increased rDNA transcriptional activity was found in schizophrenia patients in the cumulative analysis of all DRN subnuclei (t test, P = 0.02). Further subgroup analysis revealed that it was an effect specific for residual schizophrenia versus paranoid schizophrenia or control groups (ANOVA, P = 0.002). This effect was confounded neither by suicide nor by antipsychotic medication. Our findings suggest that increased activity of rDNA in DRN neurons is a distinct phenomenon in schizophrenia, particularly in residual patients. An activation of the rDNA transcription in DRN neurons may represent a compensatory mechanism to overcome the previously described prefrontal serotonergic hypofunction in this diagnostic subgroup.

Perspectives on stress resilience and adolescent neurobehavioral function

Interest in adolescence as a crucial stage of neurobehavioral maturation is growing, as is the concern of how stress may perturb this critical period of development. Though it is well recognized that stress-related vulnerabilities increase during adolescence, not all adolescent individuals are uniformly affected by stress nor do stressful experiences inevitability lead to negative outcomes. Indeed, many adolescents show resilience to stress-induced dysfunctions. However, relatively little is known regarding the mechanisms that may mediate resilience to stress in adolescence. The goal of this brief review is to bring together a few separate, yet related lines of research that highlight specific variables that may influence stress resilience during adolescence, including early life programming of the hypothalamic-pituitary-adrenal (HPA) axis, stress inoculation, and genetic predisposition. Though we are far from a clear understanding of the factors that mediate resistance to stress-induced dysfunctions, it is imperative that we identify and delineate these aspects of resilience to help adolescents reach their full potential, even in the face of adversity.

Epigenetic mechanisms of perinatal programming: translational approaches from rodent to human and back

Perinatal life is a period of enhanced plasticity and susceptibility to environmental effects via the maternal environment or parental care. A variety of studies have indicated that epigenetic mechanisms, which can alter gene function without a change in gene sequence, play a role in setting developmental trajectories that impact health, including mental health. This chapter reviews examples of translational approaches to the study of biological embedding of mental health via differences in parental care.

Genetic and early environmental influences on the serotonin system: consequences for brain development and risk for psychopathology

BACKGROUND

Despite more than 60 years of research in the role of serotonin (5-HT) in psychopathology, many questions still remain. From a developmental perspective, studies have provided more insight into how 5-HT dysfunctions acquired in utero or early in life may modulate brain development. This paper discusses the relevance of the developmental role of 5-HT for the understanding of psychopathology. We review developmental milestones of the 5-HT system, how genetic and environmental 5-HT disturbances could affect brain development and the potential role of DNA methylation in 5-HT genes for brain development.

METHODS

Studies were identified using common databases (e.g., PubMed, Google Scholar) and reference lists.

RESULTS

Despite the widely supported view that the 5-HT system matures in early life, different 5-HT receptors, proteins and enzymes have different developmental patterns, and development is brain region-specific. A disruption in 5-HT homeostasis during development may lead to structural and functional changes in brain circuits that modulate emotional stress responses, including subcortical limbic and (pre)frontal areas. This may result in a predisposition to psychopathology. DNA methylation might be one of the underlying physiologic mechanisms.

LIMITATIONS

There is a need for prospective studies. The impact of stressors during adolescence on the 5-HT system is understudied. Questions regarding efficacy of drugs acting on 5-HT still remain.

CONCLUSION

A multidisciplinary and longitudinal approach in designing studies on the role of 5-HT in psychopathology might help to bring us closer to the understanding of the role of 5-HT in psychopathology.

Early life stress in fathers improves behavioural flexibility in their offspring

Traumatic experiences in childhood can alter behavioural responses and increase the risk for psychopathologies across life, not only in the exposed individuals but also in their progeny. In some conditions, such experiences can however be beneficial and facilitate the appraisal of adverse environments later in life. Here we expose newborn mice to unpredictable maternal separation combined with unpredictable maternal stress (MSUS) for 2 weeks and assess the impact on behaviour in the offspring when adult. We show that MSUS in male mice favours goal-directed behaviours and behavioural flexibility in the adult offspring. This effect is accompanied by epigenetic changes involving histone post-translational modifications at the mineralocorticoid receptor (MR) gene and decreased MR expression in the hippocampus. Mimicking these changes pharmacologically in vivo reproduces the behavioural phenotype. These findings highlight the beneficial impact that early adverse experiences can have in adulthood, and the implication of epigenetic modes of gene regulation.

Scrutinizing the epigenetics revolution

Epigenetics is one of the most rapidly expanding fields in the life sciences. Its rise is frequently framed as a revolutionary turn that heralds a new epoch both for gene-based epistemology and for the wider discourse on life that pervades knowledge-intensive societies of the molecular age. The fundamentals of this revolution remain however to be scrutinized, and indeed the very contours of what counts as 'epigenetic' are often blurred. This is reflected also in the mounting discourse on the societal implications of epigenetics, in which vast expectations coexist with significant uncertainty about what aspects of this science are most relevant for politics or policy alike. This is therefore a suitable time to reflect on the directions that social theory could most productively take in the scrutiny of this revolution. Here we take this opportunity in both its scholarly and normative dimension, that is, proposing a roadmap for social theorizing on epigenetics that does not shy away from, and indeed hopefully guides, the framing of its most socially relevant outputs. To this end, we start with an epistemological reappraisal of epigenetic discourse that valorizes the blurring of meanings as a critical asset for the field and privileged analytical entry point. We then propose three paths of investigation. The first looks at the structuring elements of controversies and visions around epigenetics. The second probes the mutual constitution between the epigenetic reordering of living phenomena and the normative settlements that orient individual and collective responsibilities. The third highlights the material import of epigenetics and the molecularization of culture that it mediates. We suggest that these complementary strands provide both an epistemically and socially self-reflective framework to advance the study of epigenetics as a molecular juncture between nature and nurture and thus as the new critical frontier in the social studies of the life sciences.

The role of epigenetics in cognitive ageing

OBJECTIVE

As the population is ageing, a better understanding of the underlying causes of age-related cognitive decline (cognitive ageing) is required. Epigenetic dysregulation is proposed as one of the underlying mechanisms for cognitive ageing. We review the current knowledge on epigenetics and cognitive ageing and appraise the potential of epigenetic preventative and therapeutic interventions.

DESIGN

Articles on cognitive ageing and epigenetics in English were identified.

RESULTS

Epigenetic dysregulation occurs with cognitive ageing, with changes in histone post-translational modifications, DNA methylation and non-coding RNA reported. However, human studies are lacking, with most being cross-sectional using peripheral blood samples. Pharmacological and lifestyle factors have the potential to change aberrant epigenetic profiles; but few studies have examined this in relation to cognitive ageing.

CONCLUSIONS

The relationship between epigenetic modifications and cognitive ageing is only beginning to be investigated. Epigenetic dysregulation appears to be an important feature in cognitive ageing, but whether it is an epiphenomenon or a causal factor remains to be elucidated. Clarification of the relationship between epigenetic profiles of different cell types is essential and would determine whether epigenetic marks of peripheral tissues can be used as a proxy for changes occurring in the brain. The use of lifestyle and pharmacological interventions to improve cognitive performance and quality of life of older adults needs more investigation.

The intergenerational effects of Indian Residential Schools: implications for the concept of historical trauma

The current paper reviews research that has explored the intergenerational effects of the Indian Residential School (IRS) system in Canada, in which Aboriginal children were forced to live at schools where various forms of neglect and abuse were common. Intergenerational IRS trauma continues to undermine the well-being of today's Aboriginal population, and having a familial history of IRS attendance has also been linked with more frequent contemporary stressor experiences and relatively greater effects of stressors on well-being. It is also suggested that familial IRS attendance across several generations within a family appears to have cumulative effects. Together, these findings provide empirical support for the concept of historical trauma, which takes the perspective that the consequences of numerous and sustained attacks against a group may accumulate over generations and interact with proximal stressors to undermine collective well-being. As much as historical trauma might be linked to pathology, it is not possible to go back in time to assess how previous traumas endured by Aboriginal peoples might be related to subsequent responses to IRS trauma. Nonetheless, the currently available research demonstrating the intergenerational effects of IRSs provides support for the enduring negative consequences of these experiences and the role of historical trauma in contributing to present day disparities in well-being.

The social brain meets the reactive genome: neuroscience, epigenetics and the new social biology

The rise of molecular epigenetics over the last few years promises to bring the discourse about the sociality and susceptibility to environmental influences of the brain to an entirely new level. Epigenetics deals with molecular mechanisms such as gene expression, which may embed in the organism "memories" of social experiences and environmental exposures. These changes in gene expression may be transmitted across generations without changes in the DNA sequence. Epigenetics is the most advanced example of the new postgenomic and context-dependent view of the gene that is making its way into contemporary biology. In my article I will use the current emergence of epigenetics and its link with neuroscience research as an example of the new, and in a way unprecedented, sociality of contemporary biology. After a review of the most important developments of epigenetic research, and some of its links with neuroscience, in the second part I reflect on the novel challenges that epigenetics presents for the social sciences for a re-conceptualization of the link between the biological and the social in a postgenomic age. Although epigenetics remains a contested, hyped, and often uncritical terrain, I claim that especially when conceptualized in broader non-genecentric frameworks, it has a genuine potential to reformulate the ossified biology/society debate.

Methylation potential associated with diet, genotype, protein, and metabolite levels in the Delta Obesity Vitamin Study

Micronutrient research typically focuses on analyzing the effects of single or a few nutrients on health by analyzing a limited number of biomarkers. The observational study described here analyzed micronutrients, plasma proteins, dietary intakes, and genotype using a systems approach. Participants attended a community-based summer day program for 6-14 year old in 2 years. Genetic makeup, blood metabolite and protein levels, and dietary differences were measured in each individual. Twenty-four-hour dietary intakes, eight micronutrients (vitamins A, D, E, thiamin, folic acid, riboflavin, pyridoxal, and pyridoxine) and 3 one-carbon metabolites [homocysteine (Hcy), S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH)], and 1,129 plasma proteins were analyzed as a function of diet at metabolite level, plasma protein level, age, and sex. Cluster analysis identified two groups differing in SAM/SAH and differing in dietary intake patterns indicating that SAM/SAH was a potential marker of nutritional status. The approach used to analyze genetic association with the SAM/SAH metabolites is called middle-out: SNPs in 275 genes involved in the one-carbon pathway (folate, pyridoxal/pyridoxine, thiamin) or were correlated with SAM/SAH (vitamin A, E, Hcy) were analyzed instead of the entire 1M SNP data set. This procedure identified 46 SNPs in 25 genes associated with SAM/SAH demonstrating a genetic contribution to the methylation potential. Individual plasma metabolites correlated with 99 plasma proteins. Fourteen proteins correlated with body mass index, 49 with group age, and 30 with sex. The analytical strategy described here identified subgroups for targeted nutritional interventions.

Prenatal maternal factors in the development of cognitive impairments in the offspring

Different environmental factors acting during sensitive prenatal periods can have a negative impact on neurodevelopment and predispose the individual to the development of various psychiatric conditions that often share cognitive impairments as a common component. As cognitive symptoms remain one of the most challenging and resistant aspects of mental illness to be treated pharmacologically, it is important to investigate the mechanisms underlying such cognitive deficits, with particular focus on the impact of early life adverse events that predispose the individual to mental disorders. Multiple clinical studies have, in fact, repeatedly confirmed that prenatal maternal factors, such as infection, stress or malnutrition, are pivotal in shaping behavioral and cognitive functions of the offspring, and in the past decade many preclinical studies have investigated this hypothesis. The purpose of this review is to describe recent preclinical studies aimed at dissecting the relative impact of various prenatal maternal factors on the development of cognitive impairments in offspring, focusing on animal models of prenatal stress and prenatal infection. These recent studies point to the pivotal role of prenatal stressful experiences in shaping memory and learning functions associated with specific brain structures, such as the hippocampus and the prefrontal cortex. More importantly, such experimental evidence suggests that different insults converge on similar downstream functional targets, such as cognition, which may therefore represent an endophenotype for several pathological conditions. Future studies should thus focus on investigating the mechanisms contributing to the convergent action of different prenatal insults in order to identify targets for novel therapeutic intervention.

The serotonin-BDNF duo: developmental implications for the vulnerability to psychopathology

Serotonin (5-HT) and brain-derived neurotrophin factor (BDNF) are known to modulate behavioral responses to stress and to mediate the therapeutic efficacy of antidepressant agents through neuroplastic and epigenetic mechanisms. While the two systems interact at several levels, this scenario is complicated by a number of variants including brain region specificity, 5-HT receptor selectivity and timing. Based on recent insights obtained using 5-HT transporter (5-HTT) knockout rats we here set-out and discuss the crucial role of neurodevelopmental mechanisms and the contribution of transcription factors and epigenetic modifications to this interaction and its variants. 5-HTT knockout in rats, as well as the low activity short allelic variant of the serotonin transporter human polymorphism, consistently show reduced BDNF mRNA and protein levels in the hippocampus and in the prefrontal cortex. This starts during the second postnatal week, is preceded by DNA hypermethylation during the first postnatal week, and it is developmentally paralleled by reduced expression of key transcription factors. The reduced BDNF levels, in turn, affect 5-HT1A receptor-mediated intracellular signaling and thereby the serotonergic phenotype of the neurons. We propose that such a negative spiral of modifications may affect brain development and reduce its resiliency to environmental challenges during critical time windows, which may lead to phenotypic alterations that persist for the entire life. The characterization of 5-HT-BDNF interactions will eventually increase the understanding of mental illness etiology and, possibly, lead to the identification of novel molecular targets for drug development.

The biological effects of childhood trauma

Trauma in childhood is a psychosocial, medical, and public policy problem with serious consequences for its victims and for society. Chronic interpersonal violence in children is common worldwide. Developmental traumatology, the systemic investigation of the psychiatric and psychobiological effects of chronic overwhelming stress on the developing child, provides a framework and principles when empirically examining the neurobiological effects of pediatric trauma. This article focuses on peer-reviewed literature on the neurobiological sequelae of childhood trauma in children and in adults with histories of childhood trauma.

Models of stress in nonhuman primates and their relevance for human psychopathology and endocrine dysfunction

Stressful life events have been linked to the onset of severe psychopathology and endocrine dysfunction in many patients. Moreover, vulnerability to the later development of such disorders can be increased by stress or adversity during development (e.g., childhood neglect, abuse, or trauma). This review discusses the methodological features and results of various models of stress in nonhuman primates in the context of their potential relevance for human psychopathology and endocrine dysfunction, particularly mood disorders and dysregulation of the hypothalamic-pituitary-adrenocortical (HPA) system. Such models have typically examined the effects of stress on the animals' behavior, endocrine function (primarily the HPA and hypothalamic-pituitary-gonadal systems), and, in some cases, immune status. Manipulations such as relocation and/or removal of an animal from its current social group or, alternatively, formation of a new social group can have adverse effects on all of these outcome measures that may be either transient or more persistent depending on the species, sex, and other experimental conditions. Social primates may also experience significant stress associated with their rank in the group's dominance hierarchy. Finally, stress during prenatal development or during the early postnatal period may have long-lasting neurobiological and endocrine effects that manifest in an altered ability to cope behaviorally and physiologically with later challenges. Whereas early exposure to severe stress usually results in deficient coping abilities, certain kinds of milder stressors can promote subsequent resilience in the animal. We conclude that studies of stress in nonhuman primates can model many features of stress exposure in human populations and that such studies can play a valuable role in helping to elucidate the mechanisms underlying the role of stress in human psychopathology and endocrine dysfunction.

The epigenome and nature/nurture reunification: a challenge for anthropology

Recognition among molecular biologists of variables external to the body that can bring about hereditable changes in gene expression or cellular phenotypes has reignited nature/nurture discussion. These epigenetic findings may well set off a new round of somatic reductionism because research is confined largely to the molecular level. A brief review of the late nineteenth-century formulation of the nature/nurture concept is followed by a discussion of the positions taken by Boas and Kroeber on this matter. I then illustrate how current research into Alzheimer's disease uses a reductionistic approach, despite epigenetic findings in this field that make the shortcomings of reductionism clear. In order to transcend the somatic reductionism associated with epigenetics, drawing on concepts of local biologies and embedded bodies, anthropologists can carry out research in which epigenetic findings are contextualized in the specific historical, socio/political, and environmental realities of lived experience.

High fat diet induces hypermethylation of the hypothalamic Pomc promoter and obesity in post-weaning rats

Impaired response of the brain to the leptin signal leads to a persisting dysregulation of food intake and energy balance. High plasma leptin or insulin should activate proopiomelanocortin (POMC), the precursor of the anorexigenic neuropeptide α-melanocyte-stimulating hormone (α-MSH) in the hypothalamic arcuate nucleus (ARC). Nevertheless, in obesity, this signal transduction pathway might be impaired. In this study we investigated whether chronic high fat (HF) diet consumption from post-weaning to adulthood increases CpG methylation of the Pomc promoter. The hypothesis that this would disrupt the essential binding of the transcription factor Sp1 to the Pomc promoter was tested. Male rats were raised from postnatal day 21 till 90 on either HF or standard diet. As a result HF fed rats were significantly heavier, with high leptin and insulin levels in their plasma but almost no changes in ARC mRNA expression levels of Pomc. The Pomc promoter area in the HF-treated rats was found to be hypermethylated. Furthermore, there was a direct correlation in individual rats between CpG methylation at specific sites that affect Sp1 binding and plasma leptin levels and/or body weight. Although, as expected the HF diet resulted in up-regulation of Sp1, the binding of Sp1 to the hypermethylated Pomc promoter was significantly reduced. Therefore, we suggest that hypermethylation on the promoter region of the Pomc gene can emerge at post-lactation periods and interfere with transcription factor binding, thus blocking the effects of high leptin levels, leading to obesity.

Mapping the new molecular landscape: social dimensions of epigenetics

Epigenetics is the study of changes in gene expression caused by mechanisms other than changes in the DNA itself. The field is rapidly growing and being widely promoted, attracting attention in diverse arenas. These include those of the social sciences, where some researchers have been encouraged by the resonance between imaginaries of development within epigenetics and social theory. Yet, sustained attention from science and technology studies (STS) scholars to epigenetics and the praxis it propels has been lacking. In this article, we reflexively consider some of the ways in which epigenetics is being constructed as an area of biomedical novelty and discuss the content and logics underlying the ambivalent promises being made by scientists working in this area. We then reflect on the scope, limits and future of engagements between epigenetics and the social sciences. Our discussion is situated within wider literatures on biomedicine and society, the politics of "interventionist STS," and on the problems of "caseness" within empirical social science.

The neurobiological correlates of childhood adversity and implications for treatment

OBJECTIVE

This article provides an overview of research on the neurobiological correlates of childhood adversity and a selective review of treatment implications.

METHOD

Findings from a broad array of human and animal studies of early adversity were reviewed.

RESULTS

Topics reviewed include neuroendocrine, neurotrophic, neuroimaging, and cognitive effects of adversity, as well as genetic and epigenetic influences. Effects of early-life stress on treatment outcome are considered, and development of treatments designed to address the neurobiological abnormalities is discussed.

CONCLUSION

Early adversity is associated with abnormalities of several neurobiological systems that are implicated in the development of psychopathology and other medical conditions. Early-life stress negatively impacts treatment outcome, and individuals may require treatments that are specific to this condition.

Ribosomal DNA transcription in the anterior cingulate cortex is decreased in unipolar but not bipolar I depression

The anterior cingulate cortex (AC) is consistently implicated in the pathophysiology of depression. However, it is not clear whether unipolar and bipolar depression display distinct neuropathological features. Therefore, the objective of this post-mortem study was to re-evaluate this important issue. Brains from 9 patients with major depressive disorder (MDD) and 11 patients with bipolar disorder (BD) subtype I depression as well as 24 matched controls were analysed. The argyrophilic nucleolar organiser region (AgNOR) silver-staining method was applied on paraffin-embedded brain sections in order to assess the transcriptional activity of ribosomal DNA (rDNA) in layer III and V pyramidal neurons of the dorsal and ventral AC in both hemispheres. An AgNOR area decrease suggestive of a diminished transcriptional activity of rDNA was found in the MDD group both versus controls and versus the BD group. The effect was specific for the right hemisphere and dorsal AC and was restricted to layer V pyramidal neurons. The results suggest that only patients with MDD display region-specific chronic hypoactivity of these output neurons, which are critical for mood regulation. Furthermore, in our cohort, unipolar and bipolar I depression could be differentiated relative to the presumed AC hypoactivity and psychotropic medication did not counteract the observed effect.

Home visiting and the biology of toxic stress: opportunities to address early childhood adversity

Home visiting is an important mechanism for minimizing the lifelong effects of early childhood adversity. To do so, it must be informed by the biology of early brain and child development. Advances in neuroscience, epigenetics, and the physiology of stress are revealing the biological mechanisms underlying well-established associations between early childhood adversity and suboptimal life-course trajectories. Left unchecked, mediators of physiologic stress become toxic, alter both genome and brain, and lead to a vicious cycle of chronic stress. This so-called "toxic stress" results a wide array of behavioral attempts to blunt the stress response, a process known as "behavioral allostasis." Although behaviors like smoking, overeating, promiscuity, and substance abuse decrease stress transiently, over time they become maladaptive and result in the unhealthy lifestyles and noncommunicable diseases that are the leading causes of morbidity and mortality. The biology of toxic stress and the concept of behavioral allostasis shed new light on the developmental origins of lifelong disease and highlight opportunities for early intervention and prevention. Future efforts to minimize the effects of childhood adversity should focus on expanding the capacity of caregivers and communities to promote (1) the safe, stable, and nurturing relationships that buffer toxic stress, and (2) the rudimentary but foundational social-emotional, language, and cognitive skills needed to develop healthy, adaptive coping skills. Building these critical caregiver and community capacities will require a public health approach with unprecedented levels of collaboration and coordination between the healthcare, childcare, early education, early intervention, and home visiting sectors.

Increased serotonin transporter gene (SERT) DNA methylation is associated with bullying victimization and blunted cortisol response to stress in childhood: a longitudinal study of discordant monozygotic twins

BACKGROUND

Childhood adverse experiences are known to induce persistent changes in the hypothalamic-pituitary-adrenal (HPA) axis reactivity to stress. However, the mechanisms by which these experiences shape the neuroendocrine response to stress remain unclear. Method We tested whether bullying victimization influenced serotonin transporter gene (SERT) DNA methylation using a discordant monozygotic (MZ) twin design. A subsample of 28 MZ twin pairs discordant for bullying victimization, with data on cortisol and DNA methylation, were identified in the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative 1994-1995 cohort of families with twins.

RESULTS

Bullied twins had higher SERT DNA methylation at the age of 10 years compared with their non-bullied MZ co-twins. This group difference cannot be attributed to the children's genetic makeup or their shared familial environments because of the study design. Bullied twins also showed increasing methylation levels between the age of 5 years, prior to bullying victimization, and the age of 10 years whereas no such increase was detected in non-bullied twins across time. Moreover, children with higher SERT methylation levels had blunted cortisol responses to stress.

CONCLUSIONS

Our study extends findings drawn from animal models, supports the hypothesis that early-life stress modifies DNA methylation at a specific cytosine-phosphate-guanine (CpG) site in the SERT promoter and HPA functioning and suggests that these two systems may be functionally associated.

One ring to rule them all?--Temporospatial specificity of deep brain stimulation for treatment-resistant depression

Deep brain stimulation (DBS) for intractable cases of depression has emerged as a valuable therapeutic option during the last decade. While several locations have been intensely investigated in recent years, the literature is lacking an all-encompassing perspective thereupon asking if and how these stimulation sites relate to each other and what this may imply for the underlying mechanisms of action of this treatment modality. We aim at proposing a model of DBS mechanism of action with particular focus on several puzzling aspects regarding an apparent temporo-spatial specificity of antidepressant action, i.e. the discrepancy between protracted response after initiation of stimulation and rapid relapse upon discontinuation, as well as differential effects on psychopathology. We suggest that the pre-treatment depressive state is determined by the interaction of individual traits with dysfunctional adaptive processes as responses to stress, resulting in a disease-associated, overtly dysfunctional, equilibrium. The antidepressant action of DBS is thought to modify and re-set this equilibrium in a temporospatially distinct manner by influencing the activity states of two different brain circuitries. The idea of sequential and temporospatially distinct mechanisms of action bears implications for the assessment of psychopathology and behavior in clinical and preclinical studies as well as investigations into brain circuit activity states.

Nuclear reprogramming and its role in vascular smooth muscle cells

In general terms, "nuclear reprogramming" refers to a change in gene expression profile that results in a significant switch in cellular phenotype. Nuclear reprogramming was first addressed by pioneering studies of cell differentiation during embryonic development. In recent years, nuclear reprogramming has been studied in great detail in the context of experimentally controlled dedifferentiation and transdifferentiation of mammalian cells for therapeutic purposes. In this review, we present a perspective on nuclear reprogramming in the context of spontaneous, pathophysiological phenotypic switch of vascular cells occurring in the atherosclerotic lesion. In particular, we focus on the current knowledge of epigenetic mechanisms participating in the extraordinary flexibility of the gene expression profile of vascular smooth muscle cells and other cell types participating in atherogenesis. Understanding how epigenetic changes participate in vascular cell plasticity may lead to effective therapies based on the remodelling of the vascular architecture.

Lessons learned from child sexual abuse research: prevalence, outcomes, and preventive strategies

Although child sexual abuse (CSA) is recognized as a serious violation of human well-being and of the law, no community has yet developed mechanisms that ensure that none of their youth will be sexually abused. CSA is, sadly, an international problem of great magnitude that can affect children of all ages, sexes, races, ethnicities, and socioeconomic classes. Upon invitation, this current publication aims at providing a brief overview of a few lessons we have learned from CSA scholarly research as to heighten awareness of mental health professionals on this utmost important and widespread social problem. This overview will focus on the prevalence of CSA, the associated mental health outcomes, and the preventive strategies to prevent CSA from happening in the first place.

Biological embedding in mental health: an epigenomic perspective

Human epidemiological studies and studies of animal models provide many examples by which early life experiences influence health in a long-term manner, a concept known as biological embedding. Such experiences can have profound impacts during periods of high plasticity in prenatal and early postnatal life. Epigenetic mechanisms influence gene function in the absence of changes in gene sequence. In contrast to the relative stability of gene sequences, epigenetic mechanisms appear, at least to some extent, responsive to environmental signals. To date, a few examples appear to clearly link early social experiences to epigenetic changes in pathways relevant for mental health in adulthood. Our recent work using high-throughput epigenomic techniques points to large-scale changes in gene pathways in addition to candidate genes involved in the response to psychosocial stress and neuroplasticity. Elucidation of which pathways are epigenetically labile under what conditions will enable a more complete understanding of how the epigenome can mediate environmental interactions with the genome that are relevant for mental health. In this mini-review, we provide examples of nascent research into the influence of early life experience on mental health outcomes, discuss evidence of epigenetic mechanisms that may underlie these effects, and describe challenges for research in this area.

The embodiment of adverse childhood experiences and cancer development: potential biological mechanisms and pathways across the life course

OBJECTIVES

To explore current evidence of the physiological embedding of stress to discuss whether adverse childhood experiences (ACE) causing chronic or acute stress responses may alter fundamental biological functions.

METHODS

A non-systematic review of the literature was carried out using keyword searches in Pubmed and the web of science from May to October 2011. In reference to the literature identified, we examine the potential biological pathways potentially linking exposure to ACE and cancer development and progression in adulthood.

RESULTS

These mechanisms, in interaction with social position, and mediated by subsequent environmental exposures, may ultimately lead to the development of cancer. The experience of acute or chronic stressors during sensitive periods of childhood development which can induce several known biological responses, are likely to have an impact on subsequent biological and behavioural functions depending on the timing of initial exposures, and subsequently mediated by later exposures. For this reason, childhood exposure to adversity is a likely source of both acute and chronic stressors, and can be examined as an important initial exposure on a pathway towards adult ill health.

CONCLUSIONS

Such pathways justify a life course approach to understanding cancer aetiology, which may have its origins early in life.

Twins for epigenetic studies of human aging and development

Most of the complex traits including aging phenotypes are caused by the interaction between genome and environmental conditions and the interface of epigenetics may be a central mechanism. Although modern technologies allow us high-throughput profiling of epigenetic patterns already at genome level, our understanding of genetic and environmental influences on the epigenetic processes remains limited. Twins are of special interest for genetic studies due to their genetic similarity and rearing-environment sharing. The classical twin design has made a great contribution in dissecting the genetic and environmental contributions to human diseases and complex traits. In the era of functional genomics, the valuable sample of twins is helping to bridge the gap between gene activity and the environments through epigenetic mechanisms unlimited by DNA sequence variations. We propose to extend the classical twin design to study the aging-related molecular epigenetic phenotypes and link them with environmental exposures especially early life events. Different study designs and application issues will be highlighted and novel approaches introduced with aim at making uses of twins in assessing the environmental impact on epigenetic changes during development and in the aging process.

Response to psychotherapy in borderline personality disorder and methylation status of the BDNF gene

Downregulation of brain-derived neurotrophic factor (BDNF) gene expression with corresponding increased methylation at specific promoters has been associated with stressful experiences in early life and may explain later adulthood psychopathology. We measured the percentage of methylation at BDNF CpG exons I and IV as well as plasma BDNF protein levels in 115 subjects with borderline personality disorder (BPD) and 52 controls. BPD subjects then underwent a 4-week course of intensive dialectical behavior therapy (I-DBT). BDNF methylation status and protein levels were re-assessed at the end of treatment. BPD subjects had significantly higher methylation status in both CpG regions than controls. In addition, the higher the number of childhood trauma, the higher was the methylation status. In BPD subjects, BDNF methylation significantly increased after I-DBT. Nonresponders accounted for the majority of this increase, whereas responders showed a decrease in methylation status over time. Accordingly, the changes in methylation status over time were significantly associated with changes in depression scores, hopelessness scores and impulsivity. No association was found between protein levels and BDNF methylation status. We here found a relationship between child maltreatment and higher DNA methylation of BDNF. These results moreover support the idea that these epigenetic marks may be changed through psychotherapeutic approaches and that these changes underline changes in cognitive functions.

Making the invisible visible: are health social workers addressing the social determinants of health?

This study explored the ways in which health social workers (HSW) address the social determinants of health (SDH) within their social work practice. Social workers (n = 54) employed at major hospitals across Toronto had many years of practice in health care (M = 11 years; SD = 10.32) and indicated that SDH were a top priority in their daily work; with 98% intentionally intervening with at least one and 91% attending to three or more. Health care services were most often addressed (92%), followed by housing (72%), disability (79%), income (72%), and employment security (70%). Few HSW were tackling racism, Aboriginal status, gender, or social exclusion in their daily practice.

Peripuberty stress leads to abnormal aggression, altered amygdala and orbitofrontal reactivity and increased prefrontal MAOA gene expression

Although adverse early life experiences have been found to increase lifetime risk to develop violent behaviors, the neurobiological mechanisms underlying these long-term effects remain unclear. We present a novel animal model for pathological aggression induced by peripubertal exposure to stress with face, construct and predictive validity. We show that male rats submitted to fear-induction experiences during the peripubertal period exhibit high and sustained rates of increased aggression at adulthood, even against unthreatening individuals, and increased testosterone/corticosterone ratio. They also exhibit hyperactivity in the amygdala under both basal conditions (evaluated by 2-deoxy-glucose autoradiography) and after a resident-intruder (RI) test (evaluated by c-Fos immunohistochemistry), and hypoactivation of the medial orbitofrontal (MO) cortex after the social challenge. Alterations in the connectivity between the orbitofrontal cortex and the amygdala were linked to the aggressive phenotype. Increased and sustained expression levels of the monoamine oxidase A (MAOA) gene were found in the prefrontal cortex but not in the amygdala of peripubertally stressed animals. They were accompanied by increased activatory acetylation of histone H3, but not H4, at the promoter of the MAOA gene. Treatment with an MAOA inhibitor during adulthood reversed the peripuberty stress-induced antisocial behaviors. Beyond the characterization and validation of the model, we present novel data highlighting changes in the serotonergic system in the prefrontal cortex-and pointing at epigenetic control of the MAOA gene-in the establishment of the link between peripubertal stress and later pathological aggression. Our data emphasize the impact of biological factors triggered by peripubertal adverse experiences on the emergence of violent behaviors.

Borderline personality disorder: current drug treatments and future prospects

Individuals with borderline personality disorder (BPD) suffer from marked affective disturbance, an unstable sense of self, difficulty in interpersonal relationships and heightened impulsivity, leading to high rates of self-harm and suicide. Patients are often refractory to treatment and are at high risk for acute or dangerous presentations, with a serious impact on mental health services. There has been much debate on the effectiveness of pharmacotherapy in treating different facets of the psychopathology of the disorder. Several guidelines recommend the use of antidepressant agents, mood stabilizers for affective dysregulation and impulsive-behavioural dyscontrol, and antipsychotics for cognitive-perceptual symptoms. However, concerns have recently been raised regarding the strength of evidence for these treatment recommendations in BPD. Here, we review the evidence for efficacy of the main psychotropic medications used in BPD, drawing, in particular, on evidence from randomized controlled trials and meta-analyses. Overall, meta-analysis provides little evidence to support the use of antidepressant medication in BPD outside episodes of major depression. However, there is evidence for the use of both mood stabilizers and antipsychotic medications for the treatment of specific aspects of the disorder. Most existing studies have been conducted on small numbers of patients, and there is a requirement for further large-scale trials to substantiate these findings. In addition, given the limitations of current pharmacological treatment of BPD, there is a pressing need to investigate potential new therapeutic targets, including neuropeptides, such as the opioids and vasopressin, and drugs targeted at ameliorating the biological effects of early life stress.

Early life adversity is associated with brain changes in subjects at family risk for depression

OBJECTIVE

The interplay of genetic and early environmental factors is recognized as an important factor in the aetiology of major depressive disorder (MDD). The aim of the present study was to examine whether reduced volume of hippocampus and frontal brain regions involved in emotional regulation are already present in unaffected healthy individuals at genetic risk of suffering MDD and to investigate whether early life adversity is a relevant factor interacting with these reduced brain structures.

METHOD

Twenty unaffected first-degree relatives of patients with MDD (FHP: family history positive) and 20 healthy controls (FHN: family history negative) underwent high-resolution magnetic resonance imaging. Manual tracing of hippocampal sub-regions and voxel-based morphometry was used to compare groups and find association to early life adversity.

RESULTS

FHP subjects with history of emotional abuse had significantly smaller left and right hippocampal heads. VBM also showed smaller dorsolateral prefrontal cortices (DLPFC), medial prefrontal cortices (MPFC) and anterior cortex cinguli in FHP who had a previous history of emotional abuse.

CONCLUSION

High risk individuals for depression have reduced volume of brain regions related to emotional processing in particular when they additionally suffered childhood abuse, indicating that genetic and environmental factors like early life adversity influence brain structure possibly via epigenetic mechanisms and thus structural anomalies may precede the onset of the illness.

Behavior genetics and postgenomics

The science of genetics is undergoing a paradigm shift. Recent discoveries, including the activity of retrotransposons, the extent of copy number variations, somatic and chromosomal mosaicism, and the nature of the epigenome as a regulator of DNA expressivity, are challenging a series of dogmas concerning the nature of the genome and the relationship between genotype and phenotype. According to three widely held dogmas, DNA is the unchanging template of heredity, is identical in all the cells and tissues of the body, and is the sole agent of inheritance. Rather than being an unchanging template, DNA appears subject to a good deal of environmentally induced change. Instead of identical DNA in all the cells of the body, somatic mosaicism appears to be the normal human condition. And DNA can no longer be considered the sole agent of inheritance. We now know that the epigenome, which regulates gene expressivity, can be inherited via the germline. These developments are particularly significant for behavior genetics for at least three reasons: First, epigenetic regulation, DNA variability, and somatic mosaicism appear to be particularly prevalent in the human brain and probably are involved in much of human behavior; second, they have important implications for the validity of heritability and gene association studies, the methodologies that largely define the discipline of behavior genetics; and third, they appear to play a critical role in development during the perinatal period and, in particular, in enabling phenotypic plasticity in offspring. I examine one of the central claims to emerge from the use of heritability studies in the behavioral sciences, the principle of minimal shared maternal effects, in light of the growing awareness that the maternal perinatal environment is a critical venue for the exercise of adaptive phenotypic plasticity. This consideration has important implications for both developmental and evolutionary biology.

Epigenetik–Revolution der Entwicklungspsychopathologie?

Die Epigenetik, die sich mit der Bedeutung der Gene im Kontext der menschlichen Entwicklung beschäftigt, konnte zeigen, dass genetische Wirkungen auf die Entwicklung immer auf einer Wechselwirkung zwischen Genom und Umwelt basieren. Die Annahme, der genetische Einfluss auf die (psychische) Entwicklung sei konstant und nur durch gentechnologische Maßnahmen veränderbar, ist demnach offenbar ein Fehlschluss. Es werden Grundbegriffe der Epigenetik und aktuelle Forschungsergebnisse erörtert. Desweiteren wird diskutiert, ob epigenetische Prozesse die Pathogenese psychischer Störungen beeinflussen und ob diese Prozesse an bestimmte Entwicklungsphasen gebunden sind. Anschließend wird die Epigenetik im Kontext der Klinischen Kinderpsychologie betrachtet. Es wird diskutiert, ob die Epigenetik die Entwicklungspsychopathologie grundlegend verändert und welche Konsequenzen die neuen epigenetischen Erkenntnisse für die Klinische Kinderpsychologie bereithalten.

The Genetic and Environmental Structure of the Covariation Among the Symptoms of Insomnia, Fatigue, and Depression in Adult Females

Although the co-occurrence among symptoms of insomnia, fatigue, and depression has been frequently reported, the etiology of this co-occurrence remains poorly understood. A total of 3,758 adult female twins in the United Kingdom completed a mail-out survey including six questions concerning frequency and severity of symptoms of insomnia, fatigue, and depression. Correlations among the scores of the three symptoms ranged from 0.35 to 0.44. Among various multivariate models we tested, the common-pathway model explained the data best. In the best-fitting model, the common factor was explained approximately equally by genetic and unique environmental factors (49% and 51%, respectively). In addition to the common variance, there was a significant specific variance in each symptom, where unique environmental factors were much larger than genetic factors. These results imply that although there are shared genetic liabilities for the development of symptoms of depression, fatigue, and insomnia, it is environmental experiences that make etiological distinctions among three symptoms.

Epigenetics of neurobiology and behavior during development and adulthood

Gene-environment interactions have long been recognized for their important role in mediating the development and functions of the central nervous system (CNS). The study of DNA methylation and histone modifications, biochemical processes collectively referred to as epigenetic mechanisms, is helping to elucidate how gene-environmental interactions alter neurobiology and behavior over the course of the lifespan. In this review, landmark and recent studies that highlight the role of epigenetic mechanisms in the sustained effects of early-life experiences on gene activity and behavioral outcome will be discussed. Likewise, studies that implicate epigenetics in CNS and behavioral plasticity in the adult animal will be discussed. As our current understanding of epigenetics in these capacities is still evolving, epigenetic research will continue to be of considerable interest for understanding the molecular mechanisms mediating neurobiology and behavior both within and outside of sensitive periods of development.

Individual variation and longitudinal pattern of genome-wide DNA methylation from birth to the first two years of life

Prenatal development and early childhood are critical periods for establishing the tissue-specific epigenome, and may have a profound impact on health and disease in later life. However, epigenomic profiles at birth and in early childhood remain largely unexplored. The focus of this report is to examine the individual variation and longitudinal pattern of genome-wide DNA methylation levels from birth through the first two years of life in 105 Black children (59 males and 46 females) enrolled at the Boston Medical Center. We performed epigenomic mapping of cord blood at birth and venous blood samples from the same set of children within the first two years of life using Illumina Infinium Humanmethylation27 BeadChip. We observed a wide range of inter-individual variations in genome-wide methylation at each time point including lower levels at CpG islands, TSS200, 5'UTR and 1st Exon locations, but significantly higher levels in CpG shores, shelves, TSS1500, gene body and 3'UTR. We identified CpG sites with significant intra-individual longitudinal changes in the first two years of life throughout the genome. Specifically, we identified 159 CpG sites in males and 149 CpG sites in females with significant longitudinal changes defined by both statistical significance and magnitude of changes. These significant CpG sites appeared to be located within genes with important biological functions including immunity and inflammation. Further studies are needed to replicate our findings, including analysis by specific cell types, and link those individual variations and longitudinal changes with specific health outcomes in early childhood and later life.

Social adversity in adolescence increases the physiological vulnerability to job strain in adulthood: a prospective population-based study

Background

It has been argued that the association between job strain and health could be confounded by early life exposures, and studies have shown early adversity to increase individual vulnerability to later stress. We therefore investigated if early life exposure to adversity increases the individual's physiological vulnerability job strain in adulthood.

Methodology/Principal Findings

In a population-based cohort (343 women and 330 men, 83% of the eligible participants), we examined the association between on the one hand exposure to adversity in adolescence, measured at age 16, and job strain measured at age 43, and on the other hand allostatic load at age 43. Adversity was operationalised as an index comprising residential mobility and crowding, parental loss, parental unemployment, and parental physical and mental illness (including substance abuse). Allostatic load summarised body fat, blood pressure, inflammatory markers, glucose, blood lipids, and cortisol regulation. There was an interaction between adversity in adolescence and job strain (B = 0.09, 95% CI 0.02 to 0.16 after adjustment for socioeconomic status), particularly psychological demands, indicating that job strain was associated with increased allostatic load only among participants with adversity in adolescence. Job strain was associated with lower allostatic load in men (β = −0.20, 95% CI −0.35 to −0.06).

Conclusions/Significance

Exposure to adversity in adolescence was associated with increased levels of biological stress among those reporting job strain in mid-life, indicating increased vulnerability to environmental stressors.

Plasma antioxidant capacity is reduced in Asperger syndrome

Recent evidence suggests that children with autism have impaired detoxification capacity and may suffer from chronic oxidative stress. To our knowledge, there has been no study focusing on oxidative metabolism specifically in Asperger syndrome (a milder form of autism) or comparing this metabolism with other psychiatric disorders. In this study, total antioxidant status (TAOS), non-enzymatic (glutathione and homocysteine) and enzymatic (catalase, superoxide dismutase, and glutathione peroxidase) antioxidants, and lipid peroxidation were measured in plasma or erythrocyte lysates in a group of adolescent patients with Asperger syndrome, a group of adolescents with a first episode of psychosis, and a group of healthy controls at baseline and at 8-12 weeks. TAOS was also analyzed at 1 year. TAOS was reduced in Asperger individuals compared with healthy controls and psychosis patients, after covarying by age and antipsychotic treatment. This reduced antioxidant capacity did not depend on any of the individual antioxidant variables measured. Psychosis patients had increased homocysteine levels in plasma and decreased copper and ceruloplasmin at baseline. In conclusion, Asperger patients seem to have chronic low detoxifying capacity. No impaired detoxifying capacity was found in the first-episode psychosis group in the first year of illness.