Epigenetic programming by maternal behavior

Pharmacological Mechanism of Ketamine in Suicidal Behavior Based on Animal Models of Aggressiveness and Impulsivity: A Narrative Review

Around 700,000 people die from suicide each year in the world. Approximately 90% of suicides have a history of mental illness, and more than two-thirds occur during a major depressive episode. Specific therapeutic options to manage the suicidal crisis are limited and measures to prevent acting out also remain limited. Drugs shown to reduce the risk of suicide (antidepressants, lithium, or clozapine) necessitate a long delay of onset. To date, no treatment is indicated for the treatment of suicidality. Ketamine, a glutamate NMDA receptor antagonist, is a fast-acting antidepressant with significant effects on suicidal ideation in the short term, while its effects on suicidal acts still need to be demonstrated. In the present article, we reviewed the literature on preclinical studies in order to identify the potential anti-suicidal pharmacological targets of ketamine. Impulsive-aggressive traits are one of the vulnerability factors common to suicide in patients with unipolar and bipolar depression. Preclinical studies in rodent models with impulsivity, aggressiveness, and anhedonia may help to analyze, at least in part, suicide neurobiology, as well as the beneficial effects of ketamine/esketamine on reducing suicidal ideations and preventing suicidal acts. The present review focuses on disruptions in the serotonergic system (5-HT_B receptor, MAO-A enzyme), neuroinflammation, and/or the HPA axis in rodent models with an impulsive/aggressive phenotype, because these traits are critical risk factors for suicide in humans. Ketamine can modulate these endophenotypes of suicide in human as well as in animal models. The main pharmacological properties of ketamine are then summarized. Finally, numerous questions arose regarding the mechanisms by which ketamine may prevent an impulsive-aggressive phenotype in rodents and suicidal ideations in humans. Animal models of anxiety/depression are important tools to better understand the pathophysiology of depressed patients, and in helping develop novel and fast antidepressant drugs with anti-suicidal properties and clinical utility.

An integrative framework and recommendations for the study of DNA methylation in the context of race and ethnicity

Human social epigenomics research is critical to elucidate the intersection of social and genetic influences underlying racial and ethnic differences in health and development. However, this field faces major challenges in both methodology and interpretation with regard to disentangling confounded social and biological aspects of race and ethnicity. To address these challenges, we discuss how these constructs have been approached in the past and how to move forward in studying DNA methylation (DNAm), one of the best-characterized epigenetic marks in humans, in a responsible and appropriately nuanced manner. We highlight self-reported racial and ethnic identity as the primary measure in this field, and discuss its implications in DNAm research. Racial and ethnic identity reflects the biological embedding of an individual's sociocultural experience and environmental exposures in combination with the underlying genetic architecture of the human population (i.e., genetic ancestry). Our integrative framework demonstrates how to examine DNAm in the context of race and ethnicity, while considering both intrinsic factors-including genetic ancestry-and extrinsic factors-including structural and sociocultural environment and developmental niches-when focusing on early-life experience. We reviewed DNAm research in relation to health disparities given its relevance to race and ethnicity as social constructs. Here, we provide recommendations for the study of DNAm addressing racial and ethnic differences, such as explicitly acknowledging the self-reported nature of racial and ethnic identity, empirically examining the effects of genetic variants and accounting for genetic ancestry, and investigating race-related and culturally regulated environmental exposures and experiences.

Supplementary Information

The online version contains supplementary material available at 10.1007/s44155-023-00039-z.

Genome-Environment Interactions and Psychiatric Disorders

Environmental factors are known to interact with the genome by altering epigenetic mechanisms regulating gene expression and contributing to the pathogenesis of psychiatric disorders. This article is a narrative review of how the major environmental factors contribute to the pathogenesis of common psychiatric disorders such as schizophrenia, bipolar disorder, major depressive disorder, and anxiety disorder this way. The cited articles were published between 1 January 2000 and 31 December 2022 and were obtained from PubMed and Google Scholar. The search terms used were as follows: gene or genetic; genome; environment; mental or psychiatric disorder; epigenetic; and interaction. The following environmental factors were found to act epigenetically on the genome to influence the pathogenesis of psychiatric disorders: social determinants of mental health, maternal prenatal psychological stress, poverty, migration, urban dwelling, pregnancy and birth complications, alcohol and substance abuse, microbiota, and prenatal and postnatal infections. The article also discusses the ways by which factors such as drugs, psychotherapy, electroconvulsive therapy, and physical exercise act epigenetically to alleviate the symptoms of psychiatric disorders in affected patients. These data will be useful information for clinical psychiatrists and those researching the pathogenesis and treatment of psychiatric disorders.

Novel insights into maize (Zea mays) development and organogenesis for agricultural optimization

In maize, intrinsic hormone activities and sap fluxes facilitate organogenesis patterning and plant holistic development; these hormone movements should be a primary focus of developmental biology and agricultural optimization strategies. Maize (Zea mays) is an important crop plant with distinctive life history characteristics and structural features. Genetic studies have extended our knowledge of maize developmental processes, genetics, and molecular ecophysiology. In this review, the classical life cycle and life history strategies of maize are analyzed to identify spatiotemporal organogenesis properties and develop a definitive understanding of maize development. The actions of genes and hormones involved in maize organogenesis and sex determination, along with potential molecular mechanisms, are investigated, with findings suggesting central roles of auxin and cytokinins in regulating maize holistic development. Furthermore, investigation of morphological and structural characteristics of maize, particularly node ubiquity and the alternate attachment pattern of lateral organs, yields a novel regulatory model suggesting that maize organ initiation and subsequent development are derived from the stimulation and interaction of auxin and cytokinin fluxes. Propositions that hormone activities and sap flow pathways control organogenesis are thoroughly explored, and initiation and development processes of distinctive maize organs are discussed. Analysis of physiological factors driving hormone and sap movement implicates cues of whole-plant activity for hormone and sap fluxes to stimulate maize inflorescence initiation and organ identity determination. The physiological origins and biogenetic mechanisms underlying maize floral sex determination occurring at the tassel and ear spikelet are thoroughly investigated. The comprehensive outline of maize development and morphogenetic physiology developed in this review will enable farmers to optimize field management and will provide a reference for de novo crop domestication and germplasm improvement using genome editing biotechnologies, promoting agricultural optimization.

History of "Serve and Return" and a Synthesis of the Literature on its Impacts on Children's Health and Development

Parent/caregiver sensitivity and responsiveness are important for children's health and development. The "serve and return" metaphor was created to help providers and caregivers understand the importance of sensitive and responsive early caregiving. In this review, we explain the concept of "serve and return", outline historical and theoretical principles that culminated in this metaphor, highlight parent and child constructs associated with "serve and return" interactions, and synthesize literature on sensitive and responsive caregiving and children's health and developmental outcomes. Nurses and other healthcare professionals in public policy, clinical, community, education, and research roles need knowledge of "serve and return" interactions.

A zinc finger transcription factor tunes social behaviors by controlling transposable elements and immune response in prefrontal cortex

The neurobiological origins of social behaviors are incompletely understood. Here we utilized synthetic biology approaches to reprogram the function of ZFP189, a transcription factor whose expression and function in the rodent prefrontal cortex was previously determined to be protective against stress-induced social deficits. We created novel synthetic ZFP189 transcription factors including ZFP189VPR, which activates the transcription of target genes and therefore exerts opposite functional control from the endogenous, transcriptionally repressive ZFP189WT. Upon viral delivery of these synthetic ZFP189 transcription factors to mouse prefrontal cortex, we observe that ZFP189-mediated transcriptional control promotes mature dendritic spine morphology on transduced pyramidal neurons. Interestingly, dysregulation of ZFP189-mediated transcription in this brain area, achieved by delivery of synthetic ZFP189VPR, precipitates social behavioral deficits in terms of social interaction, motivation, and the cognition necessary for the maintenance of social hierarchy, without other observable behavioral deficits. By performing RNA sequencing in virally manipulated prefrontal cortex tissues, we discover that ZFP189 transcription factors of opposing regulatory function have opposite influence on the expression of genetic transposable elements as well as genes that participate in immune functions. Collectively, this work reveals that ZFP189 function in the prefrontal cortex coordinates structural and transcriptional neuroadaptations necessary for social behaviors by binding transposable element-rich regions of DNA to regulate immune-related genes. Given the evidence for a co-evolution of social behavior and the brain immune response, we posit that ZFP189 may have evolved to augment brain transposon-associated immune function as a way of enhancing an animal's capacity for functioning in social groups.

Annual Research Review: Emotion processing in offspring of mothers with depression diagnoses - a systematic review of neural and physiological research

BACKGROUND

Theories of the intergenerational transmission of depression emphasize alterations in emotion processing among offspring of depressed mothers as a key risk mechanism, raising questions about biological processes contributing to these alterations. The objective of this systematic annual research review was to examine and integrate studies of the associations between maternal depression diagnoses and offspring's emotion processing from birth through adolescence across biological measures including autonomic psychophysiology, electroencephalography (EEG), magnetoencephalography (MEG), event-related potentials (ERP), and structural and functional magnetic resonance imaging (MRI).

METHODS

The review was conducted in accordance with the PRISMA 2020 standards. A systematic search was conducted in PsycInfo and PubMed in 2022 for studies that included, 1) mothers with and without DSM-defined depressive disorders assessed via a clinical or diagnostic interview, and 2) measures of offspring emotion processing assessed at the psychophysiological or neural level between birth and 18 years of age.

RESULTS

Findings from 64 studies indicated that young offspring of mothers with depression histories exhibit heightened corticolimbic activation to negative emotional stimuli, reduced left frontal brain activation, and reduced ERP and mesocorticolimbic responses to reward cues compared to offspring of never-depressed mothers. Further, activation of resting-state networks involved in affective processing differentiate offspring of depressed relative to nondepressed mothers. Some of these alterations were only apparent among youth of depressed mothers exposed to negative environmental contexts or exhibiting current emotional problems. Further, some of these patterns were observable in infancy, reflecting very early emerging vulnerabilities.

CONCLUSIONS

This systematic review provides evidence that maternal depression is associated with alterations in emotion processing across several biological units of analysis in offspring. We present a preliminary conceptual model of the role of deficient emotion processing in pathways from maternal depression to offspring psychopathology and discuss future research avenues addressing limitations of the existing research and clinical implications.

Human myeloid progenitor glucocorticoid receptor activation causes genomic instability, type 1 IFN- response pathway activation and senescence in differentiated microglia; an early life stress model

One form of early life stress, prenatal exposure to glucocorticoids (GCs), confers a higher risk of psychiatric and neurodevelopmental disorders in later life. Increasingly, the importance of microglia in these disorders is recognized. Studies on GCs exposure during microglial development have been limited, and there are few, if any, human studies. We established an in vitro model of ELS by continuous pre-exposure of human iPS-microglia to GCs during primitive hematopoiesis (the critical stage of iPS-microglial differentiation) and then examined how this exposure affected the microglial phenotype as they differentiated and matured to microglia, using RNA-seq analyses and functional assays. The iPS-microglia predominantly expressed glucocorticoid receptors over mineralocorticoid receptors, and in particular, the GR-α splice variant. Chronic GCs exposure during primitive hematopoiesis was able to recapitulate in vivo ELS effects. Thus, pre-exposure to prolonged GCs resulted in increased type I interferon signaling, the presence of Cyclic GMP-AMP synthase-positive (cGAS) micronuclei, cellular senescence and reduced proliferation in the matured iPS-microglia. The findings from this in vitro ELS model have ramifications for the responses of microglia in the pathogenesis of GC- mediated ELS-associated disorders such as schizophrenia, attention-deficit hyperactivity disorder and autism spectrum disorder.

Epigenetic Mechanisms Involved in the Effects of Maternal Hyperhomocysteinemia on the Functional State of Placenta and Nervous System Plasticity in the Offspring

According to modern view, susceptibility to diseases, specifically to cognitive and neuropsychiatric disorders, can form during embryonic development. Adverse factors affecting mother during the pregnancy increase the risk of developing pathologies. Despite the association between elevated maternal blood homocysteine (Hcy) and fetal brain impairments, as well as cognitive deficits in the offspring, the role of brain plasticity in the development of these pathologies remains poorly studied. Here, we review the data on the negative impact of hyperhomocysteinemia (HHcy) on the neural plasticity, in particular, its possible influence on the offspring brain plasticity through epigenetic mechanisms, such as changes in intracellular methylation potential, activity of DNA methyltransferases, DNA methylation, histone modifications, and microRNA expression in brain cells. Since placenta plays a key role in the transport of nutrients and transmission of signals from mother to fetus, its dysfunction due to aberrant epigenetic regulation can affect the development of fetal CNS. The review also presents the data on the impact of maternal HHcy on the epigenetic regulation in the placenta. The data presented in the review are not only interesting from purely scientific point of view, but can help in understanding the role of HHcy and epigenetic mechanisms in the pathogenesis of diseases, such as pregnancy pathologies resulting in the delayed development of fetal brain, cognitive impairments in the offspring during childhood, and neuropsychiatric and neurodegenerative disorders later in life, as well as in the search for approaches for their prevention using neuroprotectors.

By what molecular mechanisms do social determinants impact cardiometabolic risk?

While it is well known from numerous epidemiologic investigations that social determinants (socioeconomic, environmental, and psychosocial factors exposed to over the life-course) can dramatically impact cardiovascular health, the molecular mechanisms by which social determinants lead to poor cardiometabolic outcomes are not well understood. This review comprehensively summarizes a variety of current topics surrounding the biological effects of adverse social determinants (i.e., the biology of adversity), linking translational and laboratory studies with epidemiologic findings. With a strong focus on the biological effects of chronic stress, we highlight an array of studies on molecular and immunological signaling in the context of social determinants of health (SDoH). The main topics covered include biomarkers of sympathetic nervous system and hypothalamic-pituitary-adrenal axis activation, and the role of inflammation in the biology of adversity focusing on glucocorticoid resistance and key inflammatory cytokines linked to psychosocial and environmental stressors (PSES). We then further discuss the effect of SDoH on immune cell distribution and characterization by subset, receptor expression, and function. Lastly, we describe epigenetic regulation of the chronic stress response and effects of SDoH on telomere length and aging. Ultimately, we highlight critical knowledge gaps for future research as we strive to develop more targeted interventions that account for SDoH to improve cardiometabolic health for at-risk, vulnerable populations.

Epigenetic Effects of Social Stress and Epigenetic Inheritance

Social events that cause stress can cause epigenetic changes on living things. The study of the effects of social events experienced by an individual on epigenetic marks on the genome has created the field of social epigenetics. Social epigenetics examines the effects of psychosocial stress factors such as poverty, war trauma and childhood abuse on epigenetic mechanisms. Epigenetic mechanisms alter chemical markers in the genome structure without changing the DNA sequence. Among these mechanisms, DNA methylation in particular may have different phenotypic effects in response to stressors that may occur in the psychosocial environment. Post-traumatic stress disorder is one of the most significant proofs of the effects of epigenetic expressions altered due to traumatic events on the phenotype. The field of epigenetic inheritance has shown that epigenetic changes triggered by environmental influences can, in some cases, be transmitted through generations. This field provides a better understanding of the basis of many psychological disorders. This review provides an overview of social epigenetics, PTSD, and epigenetic inheritance.

Mechanisms of Maternal Diet-Induced Obesity Affecting the Offspring Brain and Development of Affective Disorders

Depression and metabolic disease are common disorders that share a bidirectional relationship and continue to increase in prevalence. Maternal diet and maternal behaviour both profoundly influence the developmental trajectory of offspring during the perinatal period. At an epidemiological level, both maternal depression and obesity during pregnancy have been shown to increase the risk of neuropsychiatric disease in the subsequent generation. Considerable progress has been made to understand the mechanisms by which maternal obesity disrupts the developing offspring gut-brain axis, priming offspring for the development of affective disorders. This review outlines such mechanisms in detail, including altered maternal care, the maternal microbiome, inflammation, breast milk composition, and maternal and placental metabolites. Subsequently, offspring may be prone to developing gut-brain interaction disorders with concomitant changes to brain energy metabolism, neurotransmission, and behaviour, alongside gut dysbiosis. The gut microbiome may act as a key modifiable, and therefore treatable, feature of the relationship between maternal obesity and the offspring brain function. Further studies examining the relationship between maternal nutrition, the maternal microbiome and metabolites, and offspring neurodevelopment are warranted to identify novel therapeutic targets.

How to save a life: From neurobiological underpinnings to psychopharmacotherapies in the prevention of suicide

The impact of suicide on our societies, mental healthcare, and public health is beyond questionable. Every year approximately 700 000 lives are lost due to suicide around the world (WHO, 2021); more people die by suicide than by homicide and war. Although suicide is a key issue and reducing suicide mortality is a global imperative, suicide is a highly complex biopsychosocial phenomenon, and in spite of several suicidal models developed in recent years and a high number of suicide risk factors identified, we still have neither a sufficient understanding of underpinnings of suicide nor adequate management strategies to reduce its prevalence. The present paper first overviews the background of suicidal behavior including its epidemiology, prevalence, age and gender correlations and its association with neuropsychiatric disorders as well as its clinical assessment. Then we give an overview of the etiological background, including its biopsychosocial contexts, genetics and neurobiology. Based on the above, we then provide a critical overview of the currently available intervention options to manage and reduce risk of suicide, including psychotherapeutic modalities, traditional medication classes also providing an up-to-date overview on the antisuicidal effects of lithium, as well as novel molecules such as esketamine and emerging medications and further molecules in development. Finally we give a critical overview on our current knowledge on using neuromodulatory and biological therapies, such as ECT, rTMS, tDCS and other options.

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

BACKGROUND

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

METHODS

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

RESULTS

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

LIMITATIONS

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

CONCLUSION

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

How can childhood maltreatment affect post-traumatic stress disorder in adult: Results from a composite null hypothesis perspective of mediation analysis

Background

A greatly growing body of literature has revealed the mediating role of DNA methylation in the influence path from childhood maltreatment to psychiatric disorders such as post-traumatic stress disorder (PTSD) in adult. However, the statistical method is challenging and powerful mediation analyses regarding this issue are lacking.

Methods

To study how the maltreatment in childhood alters long-lasting DNA methylation changes which further affect PTSD in adult, we here carried out a gene-based mediation analysis from a perspective of composite null hypothesis in the Grady Trauma Project (352 participants and 16,565 genes) with childhood maltreatment as exposure, multiple DNA methylation sites as mediators, and PTSD or its relevant scores as outcome. We effectively addressed the challenging issue of gene-based mediation analysis by taking its composite null hypothesis testing nature into consideration and fitting a weighted test statistic.

Results

We discovered that childhood maltreatment could substantially affected PTSD or PTSD-related scores, and that childhood maltreatment was associated with DNA methylation which further had significant roles in PTSD and these scores. Furthermore, using the proposed mediation method, we identified multiple genes within which DNA methylation sites exhibited mediating roles in the influence path from childhood maltreatment to PTSD-relevant scores in adult, with 13 for Beck Depression Inventory and 6 for modified PTSD Symptom Scale, respectively.

Conclusion

Our results have the potential to confer meaningful insights into the biological mechanism for the impact of early adverse experience on adult diseases; and our proposed mediation methods can be applied to other similar analysis settings.

Resistance exercise was safe for the pregnancy and offspring's development and partially protected rats against early life stress-induced effects

Promising evidence points to gestational physical exercise as the key to preventing various disorders that affect the offspring neurodevelopment, but there are no studies showing the impact of resistance exercise on offspring health. Thus, the aim of this study was to investigate whether resistance exercise during pregnancy is able to prevent or to alleviate the possible deleterious effects on offspring, caused by early life-stress (ELS). Pregnant rats performed resistance exercise throughout the gestational period:they climbed a sloping ladder with a weight attached to their tail, 3 times a week. Male and female pups, on the day of birth (P0), were divided into 4 experimental groups: 1) rats of sedentary mothers (SED group); 2) rats of exercised mothers (EXE group); 3) rats of sedentary mothers and submitted to maternal separation (ELS group) and 4) rats of exercised mothers and submitted to MS (EXE + ELS group). From P1 to P10, pups from groups 3 and 4 were separated from their mothers for 3 h/day. Maternal behavior was assessed. From P30, behavioral tests were performed and on P38 the animals were euthanized and prefrontal cortex samples were collected. Oxidative stress and tissue damage analysis by Nissl staining were performed. Our results demonstrate that male rats are more susceptible to ELS than females, showing impulsive and hyperactive behavior similar to that seen in children with ADHD. This behavior was attenuated by the gestational resistance exercise. Our results demonstrate, for the first time, that resistance exercise performed during pregnancy seems to be safe for the pregnancy and offspring's neurodevelopment and are effective in preventing ELS-induced damage only in male rats. Interestingly, resistance exercise during pregnancy improved maternal care and it is reasonable to propose that this finding may be related to the protective role on the animals neurodevelopment, observed in our study.

Lasting impact of postnatal maternal separation on the developing BNST: Lifelong socioemotional consequences

Nearly one percent of children in the US experience childhood neglect or abuse, which can incite lifelong emotional and behavioral disorders. Many studies investigating the neural underpinnings of maleffects inflicted by early life stress have largely focused on dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. Newer veins of evidence suggest that exposure to early life stressors can interrupt neural development in extrahypothalamic areas as well, including the bed nucleus of the stria terminalis (BNST). One widely used approach in this area is rodent maternal separation (MS), which typically consists of separating pups from the dam for extended periods of time, over several days during the first weeks of postnatal life - a time when pups are highly dependent on maternal care for survival. MS has been shown to incite myriad lasting effects not limited to increased anxiety-like behavior, hyper-responsiveness to stressors, and social behavior deficits. The behavioral effects of MS are widespread and thus unlikely to be limited to hypothalamic mechanisms. Recent work has highlighted the BNST as a critical arbiter of some of the consequences of MS, especially socioemotional behavioral deficits. The BNST is a well-documented modulator of anxiety, reward, and social behavior by way of its connections with hypothalamic and extra-hypothalamic systems. Moreover, during the postnatal period when MS is typically administered, the BNST undergoes critical neural developmental events. This review highlights evidence that MS interferes with neural development to permanently alter BNST circuitry, which may account for a variety of behavioral deficits seen following early life stress. This article is part of the Special Issue on 'Fear, Anxiety and PTSD'.

Examining the biological mechanisms of human mental disorders resulting from gene-environment interdependence using novel functional genomic approaches

We explore how functional genomics approaches that integrate datasets from human and non-human model systems can improve our understanding of the effect of gene-environment interplay on the risk for mental disorders. We start by briefly defining the G-E paradigm and its challenges and then discuss the different levels of regulation of gene expression and the corresponding data existing in humans (genome wide genotyping, transcriptomics, DNA methylation, chromatin modifications, chromosome conformational changes, non-coding RNAs, proteomics and metabolomics), discussing novel approaches to the application of these data in the study of the origins of mental health. Finally, we discuss the multilevel integration of diverse types of data. Advance in the use of functional genomics in the context of a G-E perspective improves the detection of vulnerabilities, informing the development of preventive and therapeutic interventions.

Perspectives on frailty as a total life-course disease with consideration of the fetal environment

Frailty attracts research as it represents a significant target for intervention to extend the healthy life span. An unanswered question in this field is the time point during the life-course at which an individual becomes predisposed to frailty. Here, we propose that frailty has a fetal origin and should be regarded as part of the spectrum of the developmental origins of health and disease. The developmental origins of health and disease theory originated from findings linking the fetal environment to lifestyle-related disorders such as hypertension and diabetes. Coincidentally, a recent trend in frailty research also centers on vascular dysfunction and metabolic alterations as the causality of lifestyle-related disorders such as sarcopenia and dementia. Here, we explore the relationship between fetal programming, frailty-related disorders (sarcopenia and dementia), and other age-related diseases mainly based on reports on intrauterine growth restriction. We propose a "total" life-course approach to combat frailty. With this viewpoint, not only physicians and gerontologists but also obstetricians and pediatricians should team up to overcome age-related diseases in the elderly. Geriatr Gerontol Int 2023; ••: ••-••.

Early life adversity across different cell- types in the brain

Early life adversity (ELA)- which includes physical, psychological, emotional, and sexual abuse is one of the most common predictors to diverse psychopathologies later in adulthood. As ELA has a lasting impact on the brain at a developmental stage, recent findings from the field highlighted the specific contributions of different cell types to ELA and their association with long lasting consequences. In this review we will gather recent findings describing morphological, transcriptional and epigenetic alterations within neurons, glia and perineuronal nets and their associated cellular subpopulation. The findings reviewed and summarized here highlight important mechanisms underlying ELA and point to therapeutic approaches for ELA and related psychopathologies later in life.

Maternal separation and TNBS-induced gut inflammation synergistically alter the sexually differentiated stress response in rats

BACKGROUND

Neonatal maternal separation (MS) has been used to model long-lasting changes in behavior caused by neuroplastic changes associated with exposure to early-life stress. Earlier studies showed that transient gut inflammation can influence the development of irritable bowel syndrome (IBS). A prevailing paradigm of the etiology of IBS is that transient noxious events lead to long-lasting sensitization of the neural pain circuit, despite complete resolution of the initiating event. This study characterizes the changes in behaviors and neuroendocrine parameters after MS and early-phase trinitrobenzene sulfonic acid (TNBS)-induced colitis. We tested the hypothesis that MS and gut inflammation synergistically induce (1) hyperactivity in male rats and anxiety-like behaviors in female rats and (2) activation of the HPA axis in female rats and deactivation of the HPA axis in male rats after colorectal distention (CRD).

METHODS

Male and female rat pups were separated from their dams for 180 min daily from postnatal day (PND) 2 to PND 14 (MS). Early-phase colitis was induced by colorectal administration with TNBS on PND 8. The elevated plus-maze test was performed at 7 weeks. Tonic CRD was performed at 60 mmHg for 15 min at 8 weeks. Plasma ACTH and serum corticosterone were measured at baseline or after the CRD. Analysis of variance was performed for comparison among controls, TNBS, MS, and MS + TNBS.

RESULTS

In male rats, the time spent in open arms significantly differed among the groups (p < 0.005). The time spent in open arms in male MS + TNBS rats was significantly higher than that of controls (p < 0.009) or TNBS rats (p < 0.031, post hoc test). Female rats showed no difference in the time spent in open arms among the groups. MS and gut inflammation induced an increase in plasma ACTH in female rats but not in male rats at baseline.

CONCLUSIONS

These findings suggest that MS and gut inflammation synergistically induce hyperactive behavior or exaggerated hypothalamic-pituitary-adrenal axis function depending on sex.

Transcriptomic profiling of the developing brain revealed cell-type and brain-region specificity in a mouse model of prenatal stress

BACKGROUND

Prenatal stress (PS) is considered as a risk factor for many mental disorders. PS-induced transcriptomic alterations may contribute to the functional dysregulation during brain development. Here, we used RNA-seq to explore changes of gene expression in the mouse fetal brain after prenatal exposure to chronic unpredictable mild stress (CUMS).

RESULTS

We compared the stressed brains to the controls and identified groups of significantly differentially expressed genes (DEGs). GO analysis on up-regulated DEGs revealed enrichment for the cell cycle pathways, while down-regulated DEGs were mostly enriched in the neuronal pathways related to synaptic transmission. We further performed cell-type enrichment analysis using published scRNA-seq data from the fetal mouse brain and revealed cell-type-specificity for up- and down-regulated DEGs, respectively. The up-regulated DEGs were highly enriched in the radial glia, while down-regulated DEGs were enriched in different types of neurons. Cell deconvolution analysis further showed altered cell fractions in the stressed brain, indicating accumulation of neuroblast and impaired neurogenesis. Moreover, we also observed distinct brain-region expression pattern when mapping DEGs onto the developing Allen brain atlas. The up-regulated DEGs were primarily enriched in the dorsal forebrain regions including the cortical plate and hippocampal formation. Surprisingly, down-regulated DEGs were found excluded from the cortical region, but highly expressed on various regions in the ventral forebrain, midbrain and hindbrain.

CONCLUSION

Taken together, we provided an unbiased data source for transcriptomic alterations of the whole fetal brain after chronic PS, and reported differential cell-type and brain-region vulnerability of the developing brain in response to environmental insults during the pregnancy.

Associations of DNA Methylation With Behavioral Problems, Gray Matter Volumes, and Negative Life Events Across Adolescence: Evidence From the Longitudinal IMAGEN Study

BACKGROUND

Negative life events (NLEs) increase the risk for externalizing behaviors (EBs) and internalizing behaviors (IBs) in adolescence and adult psychopathology. DNA methylation associated with behavioral problems may reflect this risk and long-lasting effects of NLEs.

METHODS

To identify consistent associations between blood DNA methylation and EBs or IBs across adolescence, we conducted longitudinal epigenome-wide association studies (EWASs) using data from the IMAGEN cohort, collected at ages 14 and 19 years (n = 506). Significant findings were validated in a separate subsample (n = 823). Methylation risk scores were generated by 10-fold cross-validation and further tested for their associations with gray matter volumes and NLEs.

RESULTS

No significant findings were obtained for the IB-EWAS. The EB-EWAS identified a genome-wide significant locus in a gene linked to attention-deficit/hyperactivity disorder (ADHD) (IQSEC1, cg01460382; p = 1.26 × 10-8). Other most significant CpG sites were near ADHD-related genes and enriched for genes regulating tumor necrosis factor and interferon-γ signaling, highlighting the relevance of EB-EWAS findings for ADHD. Analyses with the EB methylation risk scores suggested that it partly reflected comorbidity with IBs in late adolescence. Specific to EBs, EB methylation risk scores correlated with smaller gray matter volumes in medial orbitofrontal and anterior/middle cingulate cortices, brain regions known to associate with ADHD and conduct problems. Longitudinal mediation analyses indicated that EB-related DNA methylation were more likely the outcomes of problematic behaviors accentuated by NLEs, and less likely the epigenetic bases of such behaviors.

CONCLUSIONS

Our findings suggest that novel epigenetic mechanisms through which NLEs exert short and longer-term effects on behavior may contribute to ADHD.

Methylation and expression of glucocorticoid receptor exon-1 variants and FKBP5 in teenage suicide-completers

A dysregulated hypothalamic-pituitary-adrenal (HPA) axis has repeatedly been demonstrated to play a fundamental role in psychiatric disorders and suicide, yet the mechanisms underlying this dysregulation are not clear. Decreased expression of the glucocorticoid receptor (GR) gene, which is also susceptible to epigenetic modulation, is a strong indicator of impaired HPA axis control. In the context of teenage suicide-completers, we have systematically analyzed the 5'UTR of the GR gene to determine the expression levels of all GR exon-1 transcript variants and their epigenetic state. We also measured the expression and the epigenetic state of the FK506-binding protein 51 (FKBP5/FKBP51), an important modulator of GR activity. Furthermore, steady-state DNA methylation levels depend upon the interplay between enzymes that promote DNA methylation and demethylation activities, thus we analyzed DNA methyltransferases (DNMTs), ten-eleven translocation enzymes (TETs), and growth arrest- and DNA-damage-inducible proteins (GADD45). Focusing on both the prefrontal cortex (PFC) and hippocampus, our results show decreased expression in specific GR exon-1 variants and a strong correlation of DNA methylation changes with gene expression in the PFC. FKBP5 expression is also increased in both areas suggesting a decreased GR sensitivity to cortisol binding. We also identified aberrant expression of DNA methylating and demethylating enzymes in both brain regions. These findings enhance our understanding of the complex transcriptional regulation of GR, providing evidence of epigenetically mediated reprogramming of the GR gene, which could lead to possible epigenetic influences that result in lasting modifications underlying an individual's overall HPA axis response and resilience to stress.

Synchrony in parent-offspring social interactions across development: A cross-species review of rodents and humans

In humans, parent-child neural synchrony has been shown to support early communication, social attunement and learning. Further, some animal species (including rodents and bats) are now known to share neural synchrony during certain forms of social behaviour. However, very little is known about the developmental origins and sequelae of neural synchrony, and whether this neural mechanism might play a causal role in the control of social and communicative behaviour across species. Rodent models are optimal for exploring such questions of causality, with a plethora of tools available for both disruption/induction (optogenetics) and even mechanistic dissection of synchrony-induction pathways (in vivo electrical or optical recording of neural activity). However, before the benefits of rodent models for advancing research on parent-infant synchrony can be realised, it is first important to address a gap in understanding the forms of parent-pup synchrony that occur during rodent development, and how these social relationships evolve over time. Accordingly, this review seeks to identify parent-pup social behaviours that could potentially drive or facilitate synchrony and to discuss key differences or limitations when comparing mouse to human models of parent-infant synchrony. Uniquely, our review will focus on parent-pup dyadic social behaviours that have particular analogies to the human context, including instrumental, social interactive and vocal communicative behaviours. This review is intended to serve as a primer on the study of neurobehavioral synchrony across human and rodent dyadic developmental models.

Omega-3 fatty acid intake during pregnancy and risk of infant maltreatment: a nationwide birth cohort - the Japan Environment and Children's Study

BACKGROUND

Intake of omega-3 polyunsaturated fatty acids (PUFAs) has favorable effects, including reducing violent and aggressive behaviors, but its association with infant maltreatment is unknown. We therefore tested the hypothesis that maternal intake of omega-3 PUFAs is associated with a lower risk of infant maltreatment.

METHODS

Participants were 92 191 mothers involved in the ongoing Japan Environment and Children's Study. Omega-3 PUFA intake during pregnancy was measured using a food frequency questionnaire. Infant maltreatment was assessed using a self-reported questionnaire administered at 1 and 6 months postpartum.

RESULTS

Analysis using the lowest quintile of intake as a reference revealed that the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for cases of 'hitting' decreased as quintiles increased, with values for the second to fifth quintiles of 0.93 (95% CI 0.77-1.13), 0.79 (95% CI 0.64-0.97), 0.78 (95% CI 0.64-0.96), and 0.72 (95% CI 0.59-0.89), respectively. Adjusted ORs (95% CIs) for 'shaking very hard' at 6 months were 0.87 (0.73-1.04), 0.81 (0.67-0.97), 0.73 (0.61-0.89), and 0.78 (0.65-0.94), respectively. Adjusted ORs for 'leaving alone at home' for the second to fifth quintiles were 0.92 (0.87-0.98), 0.91 (0.86-0.97), 0.94 (0.88-0.99), and 0.85 (0.80-0.90), respectively.

CONCLUSIONS

Higher maternal intake of omega-3 PUFAs during pregnancy was associated with fewer cases of hitting and violent shaking and leaving the child alone at home, implying a lower risk of infant maltreatment. Our results indicate the potential applicability of omega-3 PUFAs in reducing infant maltreatment.

Abnormal Chromatin Folding in the Molecular Pathogenesis of Epilepsy and Autism Spectrum Disorder: a Meta-synthesis with Systematic Searching

How DNA is folded and packaged in nucleosomes is an essential regulator of gene expression. Abnormal patterns of chromatin folding are implicated in a wide range of diseases and disorders, including epilepsy and autism spectrum disorder (ASD). These disorders are thought to have a shared pathogenesis involving an imbalance in the number of excitatory-inhibitory neurons formed during neurodevelopment; however, the underlying pathological mechanism behind this imbalance is poorly understood. Studies are increasingly implicating abnormal chromatin folding in neural stem cells as one of the candidate pathological mechanisms, but no review has yet attempted to summarise the knowledge in this field. This meta-synthesis is a systematic search of all the articles on epilepsy, ASD, and chromatin folding. Its two main objectives were to determine to what extent abnormal chromatin folding is implicated in the pathogenesis of epilepsy and ASD, and secondly how abnormal chromatin folding leads to pathological disease processes. This search produced 22 relevant articles, which together strongly implicate abnormal chromatin folding in the pathogenesis of epilepsy and ASD. A range of mutations and chromosomal structural abnormalities lead to this effect, including single nucleotide polymorphisms, copy number variants, translocations and mutations in chromatin modifying. However, knowledge is much more limited into how abnormal chromatin organisation subsequently causes pathological disease processes, not yet showing, for example, whether it leads to abnormal excitation-inhibitory neuron imbalance in human brain organoids.

Come gli stati psichici si traducono in molecole biologiche e come questo cambia la medicina e la psicologia

Nell'aprile del 2022 abbiamo pubblicato, su invito di una rivista internazionale di biologia molecolare, un'ampia review che riporta le principali evidenze scientifiche sul tema delle relazioni tra vita psichica e biologia, traendone alcune conclusioni di carattere generale sulla psicologia e la medicina (Bottaccioli, Bologna & Bottaccioli, 2022). Il presente articolo riprende alcuni dei passaggi fondamentali presentati in quella review e si collega a un precedente articolo pubblicato sul n. 4/2014 di Psicoterapia e Scienze Umane (Bottaccioli, 2014b), di cui rappresenta un aggiornamento. Dalla pubblicazione di quell'articolo le evidenze sperimentali e cliniche sull'influenza della psiche sui sistemi biologici si sono moltiplicate. Al tempo stesso, conosciamo meglio le vie e i meccanismi con cui gli stati psichici si traducono in biologia.

Sex differences matter: Males and females are equal but not the same

Sex differences between males and females can be detected early in life. They are present also later even to a much greater extent affecting our life in adulthood and a wide spectrum of physical, psychological, cognitive, and behavioral characteristics. Moreover, sex differences matter also in individual's health and disease. In this article, we reviewed at first the sex differences in brain organization and function with respect to the underlying biological mechanisms. Since the individual functional differences in the brain, in turn, shape the behavior, sex-specific psychological/behavioral differences that can be observed in infants but also adults are consequently addressed. Finally, we briefly mention sex-dependent variations in susceptibility to selected disorders as well as their pathophysiology, diagnosis, and response to therapy. The understanding of biologically determined variability between males and females can have important implications, especially in gender-specific health care. We have the impression that it is very important to emphasize that sex matters. Males and females are differently programmed by nature, and it must be respected. Even though we as males and females are not the same, we would like to emphasize that we are still equal and together form a worthy colorful continuum.

Methyl Donors, Epigenetic Alterations, and Brain Health: Understanding the Connection

Methyl donors such as choline, betaine, folic acid, methionine, and vitamins B6 and B12 are critical players in the one-carbon metabolism and have neuroprotective functions. The one-carbon metabolism comprises a series of interconnected chemical pathways that are important for normal cellular functions. Among these pathways are those of the methionine and folate cycles, which contribute to the formation of S-adenosylmethionine (SAM). SAM is the universal methyl donor of methylation reactions such as histone and DNA methylation, two epigenetic mechanisms that regulate gene expression and play roles in human health and disease. Epigenetic mechanisms have been considered a bridge between the effects of environmental factors, such as nutrition, and phenotype. Studies in human and animal models have indicated the importance of the optimal levels of methyl donors on brain health and behavior across the lifespan. Imbalances in the levels of these micronutrients during critical periods of brain development have been linked to epigenetic alterations in the expression of genes that regulate normal brain function. We present studies that support the link between imbalances in the levels of methyl donors, epigenetic alterations, and stress-related disorders. Appropriate levels of these micronutrients should then be monitored at all stages of development for a healthier brain.

Intergenerational impact of childhood trauma on hair cortisol concentrations in mothers and their young infants

Background

Alterations in stress regulation and function of the hypothalamic-pituitary-adrenal (HPA) axis during infancy may be a risk factor for the development of psychopathology later in life. Maternal childhood trauma, depression, anxiety and stressful life events are individually associated with HPA axis dysregulation. Less is known about their interdependent influence on maternal and infant stress regulation in at risk populations. In a sample of mothers with a history of depressive-, and/or anxiety disorders and their infants we explored if a history of maternal childhood trauma, current depressive and anxiety symptomatology, and recent life events were associated with maternal and infant long-term cortisol levels three months postpartum.

Methods

Data were available of 89 mothers and 49 infants. All mothers fulfilled criteria for a lifetime depressive or anxiety disorder. Diagnosis was established with a diagnostic interview. Current depressive symptomatology was assessed with the Edinburgh Postnatal Depression Scale (EPDS), current anxiety with the State-Trait Anxiety Inventory (STAI), maternal childhood trauma with the Childhood Trauma Questionnaire (CTQ) and recent life events with the Everyday Problem Checklist (EPC). Maternal and infant hair cortisol concentrations (HCC) were quantified with liquid chromatography with tandem mass spectrometry (LC-MS/MS) three months after birth. Total scores of the CTQ and subscales, EPDS, STAI, and EPC were regressed on maternal and infant HCC using regression analyses. Differences in HCC regarding trauma history were tested with t-tests. Potential confounders were identified and adjusted for.

Results

In regression analyses, a positive curvilinear relationship was found between CTQ total score and maternal HCC (n = 83, B = 0.076, SE 0.033, p = .021), but not for current depression (n = 88, B = -0.001, SE 0.011, p = .931), current anxiety (n = 88, B = 0.002, SE 0.004, p = .650) or recent life events (n = 89, B = 0.018, SE 0.032, p = .568). Analyses were adjusted for confounders. A negative linear relationship was found between maternal CTQ score and infant HCC (n = 49, β = -0.264, B = -0.006, SE 0.003, p = .052), but not for current maternal depression (n = 45, β = -0.182, B = -0.011, SE 0.008, p = .164), current maternal anxiety (n = 45, β = -0.209, B = -0.005, SE 0.003, p = .113) or recent life events (n = 46, β = -0.128, B = -0.022, SE 0.023, p = .325). Analyses were adjusted for relevant infant hair characteristics. Specifically, maternal emotional and physical neglect were related to HCC in both mothers and infants.

Conclusions

Results suggest that maternal childhood trauma is more prominent in altering maternal and infant long-term cortisol levels than perinatal depressive and anxiety symptomatology or recent life stressors in mothers with a history of depressive and/or anxiety disorders, and their infants. As infants of mothers with psychopathology are at increased risk for later psychiatric disease, future studies should investigate the interplay of possible risk factors for transgenerational transmission, intra-uterine programming of the HPA axis, including (epi-)genetic phenomena, of the HPA axis, and the influence of parenting impairment.

Effects of intranasal oxytocin on neural reward processing in children and adolescents with reactive attachment disorder: A randomized controlled trial

Reactive attachment disorder (RAD) is associated with socially and emotionally withdrawn/inhibited behaviors and reduced neural responses to rewards. Children and adolescents with RAD show aberrant attachment behaviors, and existing psychotherapies are difficult to maintain; therefore, pharmacological interventions to aid and boost treatment responses are needed. Oxytocin (OT) administration is known to promote reward functioning. We investigated whether single-use intranasal OT administration improved neural responses during reward processing in patients with RAD compared with healthy controls. Twenty-four male children and adolescents with RAD (10-18 years old) and 27 age- and sex-matched typically developing individuals (10-17 years old) were included in this randomized, double-blind, placebo-controlled, cross-over, functional magnetic resonance imaging study. Following a single intranasal OT (24 IU) or placebo administration, neural responses were investigated using a monetary reward task. In the RAD group, OT significantly increased subjective motivation scores, significantly enhanced activation in the right middle frontal gyrus, and reduced activation in the right precentral gyrus during the monetary reward task. Additional analyses revealed increased activation in the bilateral caudate at a more lenient threshold. Under placebo conditions, the severity of internalizing problems in patients with RAD was negatively correlated with ventral striatal activity. Moreover, the effect of OT on ventral striatum activity was positively associated with the severity of internalizing problems in patients with RAD. Intranasal OT administration enhanced activity in the reward pathway in male children and adolescents with RAD, suggesting that exogenous OT promotes reward processing and reward-related motivational behavior in these individuals. Further investigation is needed to fully understand the neural mechanisms of intranasal OT and identify novel targets for pediatric cases with RAD. Clinical trial registration: UMIN-CTR; UMIN000013215. URL: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000015419.

Targeted sequencing approach: Comprehensive analysis of DNA methylation and gene expression across blood and brain regions in suicide victims

OBJECTIVES

Epigenetic mechanisms are involved in regulation of many pathologies, including suicidal behaviour. However, the factors through which epigenetics affect suicidal behaviour are not fully understood.

METHODS

We analysed DNA methylation of eight neuropsychiatric genes (NR3C1, SLC6A4, HTR1A, TPH2, SKA2, MAOA, GABRA1, and NRIP3) in brain regions (hippocampus, insula, amygdala, Brodmann area 46) and blood of 25 male suicide victims and 28 male control subjects, using bisulphite next-generation sequencing.

RESULTS

Comparing mean methylation values, notable changes were observed in NR3C1 (insula p-value = 0.05), HTR1A (insula p-value < 0.001, blood p-value = 0.001), SKA2 (insula p-value = 0.03, blood p-value = 0.016), MAOA (blood p-value < 0.001), GABRA1 (insula p-value = 0.05, blood p-value = 0.024) and NRIP3 (hippocampus p-value = 0.001, insula p-value = 0.002, amygdala p-value = 0.014). Comparing methylation pattern between blood and brain, similarity was observed between blood and insula for HTR1A. Gene expression analysis in hippocampus revealed changes in expression of NR3C1 (p-value = 0.049), SLC6A4 (p-value = 0.017) and HTR1A (p-value = 0.053).

CONCLUSIONS

Results provide an insight into the altered state of DNA methylation in suicidal behaviour. Epigenetic differences could therefore affect suicidal behaviour in both previously known and in novel neuropsychiatric candidate genes.

Hair Cortisol Concentration as a Biomarker of Symptoms of Depression in the Perinatal Period

Pregnancy is a sensitive period when women experience major hormonal and psychological changes. A high prevalence of the symptoms of depression and manifested major depression rates have been reported during this period, leading to negative outcomes both for mothers and the offspring. Despite its prevalence, the aetiology of depression is not yet fully understood. Nonetheless, alterations in cortisol levels have been proposed as a reliable biomarker to identify pregnant women at risk of perinatal depression. Hair cortisol has recently been extensively used in bio-psychological studies as a suitable non-invasive biomarker for several neuropsychiatric disorders. Various studies have published evidence regarding the relationship between cortisol fluctuations during the perinatal period, measured both in hair and in other substrates, and the onset of perinatal symptoms of depression. This current review provides an overview of cortisol level changes measured in women's hair during pregnancy or the postpartum period and its association with perinatal symptoms of depression. Further studies, including repetitive measurement of both hair cortisol and depression throughout the prenatal period, must be performed to clarify the relationship between cortisol levels and perinatal symptoms of depression.

Childhood adverse events and BDNF promoter methylation in later-life

Studies have shown that the effects of early-life stress and trauma can be enduring, with long-term negative effects on health. Epigenetics, including DNA methylation, have been implicated as a potential mechanism for these effects. Brain-derived neurotropic factor (BDNF) is a neurotransmitter involved in learning and memory, and altered BDNF promoter methylation measured in peripheral tissue has been found with early-life stress. However, whether such methylation differences remain stable into later life, is unknown. This study aimed to investigate the association between childhood adversity and BDNF promoter methylation in adults aged 65 years and over. Data came from a large study of older community-dwelling individuals in France (ESPRIT). Information on three major childhood adverse events, namely abuse/maltreatment, war/natural disaster, and financial difficulties/poverty, was obtained by retrospective reporting from participants of ESPRIT study. BDNF promoter I and IV methylation was assessed in blood and buccal tissue. Linear regression analysis was performed, adjusting for age, sex, education, depression, and morbidity. Among 927 participants, there was no strong evidence that childhood abuse/maltreatment or financial difficulties/poverty were associated with BDNF methylation in older individuals. For war/natural disaster, differential methylation at four of twenty-nine CpG sites was observed, however, these would not have remained significant after correction for multiple testing. Together, these findings do not support a long-term association between adverse childhood events and BDNF methylation in older age, but further large prospective studies are needed, which do not target specific genes, but consider DNA methylation across the genome.

Early Life Stress, Neuroinflammation, and Psychiatric Illness of Adulthood

Stress exposure during early stages of life elevates the risk of developing psychopathologies and psychiatric illness in later life. The brain and immune system are not completely developed by birth and therefore continue develop after birth; this post birth development is influenced by several psychosocial factors; hence, early life stress (ELS) exposure can alter brain structural development and function. A growing number of experimental animal and observational human studies have investigated the link between ELS exposure and increased risk of psychopathology through alternations in the immune system, by evaluating inflammation biomarkers. Recent studies, including brain imaging, have also shed light on the mechanisms by which both the innate and adaptive immune systems interact with neural circuits and neurotransmitters, which affect psychopathology. Herein, we discuss the link between the experience of stress in early life and lifelong alterations in the immune system, which subsequently lead to the development of various psychiatric illnesses.

Integrative Multi-omics Analysis of Childhood Aggressive Behavior

This study introduces and illustrates the potential of an integrated multi-omics approach in investigating the underlying biology of complex traits such as childhood aggressive behavior. In 645 twins (cases = 42%), we trained single- and integrative multi-omics models to identify biomarkers for subclinical aggression and investigated the connections among these biomarkers. Our data comprised transmitted and two non-transmitted polygenic scores (PGSs) for 15 traits, 78,772 CpGs, and 90 metabolites. The single-omics models selected 31 PGSs, 1614 CpGs, and 90 metabolites, and the multi-omics model comprised 44 PGSs, 746 CpGs, and 90 metabolites. The predictive accuracy for these models in the test (N = 277, cases = 42%) and independent clinical data (N = 142, cases = 45%) ranged from 43 to 57%. We observed strong connections between DNA methylation, amino acids, and parental non-transmitted PGSs for ADHD, Autism Spectrum Disorder, intelligence, smoking initiation, and self-reported health. Aggression-related omics traits link to known and novel risk factors, including inflammation, carcinogens, and smoking.

Transgenerational Epigenetic Inheritance of Traumatic Experience in Mammals

In recent years, we have seen an increasing amount of evidence pointing to the existence of a non-genetic heredity of the effects of events such as separation from parents, threat to life, or other traumatising experiences such as famine. This heredity is often mediated by epigenetic regulations of gene expression and may be transferred even across several generations. In this review, we focus on studies which involve transgenerational epigenetic inheritance (TEI), with a short detour to intergenerational studies focused on the inheritance of trauma or stressful experiences. The reviewed studies show a plethora of universal changes which stress exposure initiates on multiple levels of organisation ranging from hormonal production and the hypothalamic-pituitary-adrenal (HPA) axis modulation all the way to cognition, behaviour, or propensity to certain psychiatric or metabolic disorders. This review will also provide an overview of relevant methodology and difficulties linked to implementation of epigenetic studies. A better understanding of these processes may help us elucidate the evolutionary pathways which are at work in the course of emergence of the diseases and disorders associated with exposure to trauma, either direct or in a previous generation.

Maternal distress, DNA methylation, and fetal programing of stress physiology in Brazilian mother-infant pairs

Maternal prenatal psychosocial stress is associated with adverse hypothalamic-pituitary-adrenal axis (HPAA) function among infants. Although the biological mechanisms influencing this process remain unknown, altered DNA methylation is considered to be one potential mechanism. We investigated associations between maternal prenatal psychological distress, infant salivary DNA methylation, and stress physiology at 12 months. Mother's distress was measured via depression and anxiety in early and late pregnancy in a cohort of 80 pregnant adolescents. Maternal hair cortisol was collected during pregnancy. Saliva samples were collected from infants at 12 months to quantify DNA methylation of three stress-related genes (FKBP5, NR3C1, OXTR) (n = 62) and diurnal cortisol (n = 29). Multivariable linear regression was used to test for associations between prenatal psychological distress, and infant DNA methylation and cortisol. Hair cortisol concentrations in late pregnancy were negatively associated with two sites of FKBP5 (site 1: B = -22.33, p = .003; site 2: B = -15.60, p = .012). Infants of mothers with elevated anxiety symptoms in late pregnancy had lower levels of OXTR2 CpG2 methylation (B = -2.17, p = .03) and higher evening salivary cortisol (B = 0.41, p = .03). Furthermore, OXTR2 methylation was inversely associated with evening cortisol (B = -0.14, p-value ≤ .001). Our results are, to our knowledge, the first evidence that the methylation of the oxytocin receptor may contribute to the regulation of HPAA during infancy.

The translational genetics of ADHD and related phenotypes in model organisms

Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent neurodevelopmental disorder resulting from the interaction between genetic and environmental risk factors. It is well known that ADHD co-occurs frequently with other psychiatric disorders due, in part, to shared genetics factors. Although many studies have contributed to delineate the genetic landscape of psychiatric disorders, their specific molecular underpinnings are still not fully understood. The use of animal models can help us to understand the role of specific genes and environmental stimuli-induced epigenetic modifications in the pathogenesis of ADHD and its comorbidities. The aim of this review is to provide an overview on the functional work performed in rodents, zebrafish and fruit fly and highlight the generated insights into the biology of ADHD, with a special focus on genetics and epigenetics. We also describe the behavioral tests that are available to study ADHD-relevant phenotypes and comorbid traits in these models. Furthermore, we have searched for new models to study ADHD and its comorbidities, which can be useful to test potential pharmacological treatments.

Protective Role of Acetate Against Depressive-Like Behaviour Associated with Letrozole-Induced PCOS Rat Model: Involvement of HDAC2 and DNA Methylation

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder amongst women of reproductive age. PCOS has been demonstrated to induce depressive-like behaviour. Epigenetic alterations such as histone deacetylation (HDAC) and DNA methylation have been suggested in major depression. However, their effects with respect to neuroinflammation are not clear. This study therefore investigated the pathogenic involvement of epigenetic changes in PCOS-associated depression and the protective role of HDACi, especially acetate. Virgin female Wistar rats (140 ± 10 g) were assigned into four groups: the groups received vehicle (control), acetate (200 mg/kg), letrozole (1 mg/kg) and letrozole plus acetate, respectively. The administrations were done concomitantly by oral gavage for 21 days. Treatment with letrozole caused hyperandrogenism, hypoestrogenism, hyperinsulinemia and multiple ovarian cysts/degenerated follicles. In addition, these animals showed depressive-like behaviours and increased expression of HDAC2 and DNA methyltransferase in PFC and hippocampal tissues. Biochemical analyses showed elevated levels of NF-κB, malondialdehyde and acetylcholine (ACH) with glutathione depletion in PFC and hippocampus as well as elevated plasma malondialdehyde and impaired anti-oxidant system in letrozole-treated animals. Histological analysis of PFC and hippocampus showed neurodegeneration in letrozole-treated animals compared with control. However, these alterations were attenuated when treated with acetate. The study demonstrates that PCOS-associated depression is characterised by neuroinflammation and elevated ACH levels, accompanied by increased expression of HDAC2/DNA methyltransferase in PFC and hippocampus. Besides, the study suggests that acetate protects against PCOS-associated depression through suppression of prefrontal and hippocampal DNA methylation and prefrontal but not hippocampal HDAC2 expression.

Adverse maternal environment alters Oprl1 variant expression in mouse hippocampus

An adverse maternal environment (AME) and Western diet (WD) in early life predispose offspring toward cognitive impairment in humans and mice. Cognitive impairment associates with hippocampal dysfunction. An important regulator of hippocampal function is the hippocampal Nociceptin/Orphanin FQ (N/OFQ) system. Previous studies find links between dysregulation of hippocampal N/OFQ receptor (NOP) expression and impaired cognitive function. NOP is encoded by the opioid receptor-like 1 (Oprl1) gene that contains multiple mRNA variants and isoforms. Regulation of Oprl1 expression includes histone modifications within the promoter. We tested the hypothesis that an AME and a postweaning WD increase the expression of hippocampal Oprl1 and select variants concurrent with altered histone code in the promoter. We created an AME-WD model combining maternal WD and prenatal environmental stress plus postweaning WD in the mouse. We analyzed the hippocampal expression of Oprl1, Oprl1 variants, and histone modifications in the Oprl1 promoter in offspring at postnatal day (P) 21 and P100. An AME and an AME-WD significantly increased the total hippocampal expression of Oprl1 and variant V4 concurrently with an increased accumulation of active histone marks in the promoter of male offspring. We concluded that an AME and an AME-WD alter hippocampal Oprl1 expression in offspring through an epigenetic mechanism in a variant-specific and sex-specific manner. Altered hippocampal Oprl1 expression may contribute to cognitive impairment seen in adult males in this model. Epigenetic regulation of Oprl1 is a potential mechanism by which an AME and a WD may contribute to neurocognitive impairment in male offspring.

Prenatal Stress and the Developing Brain: Postnatal Environments Promoting Resilience

Heightened maternal stress during pregnancy is associated with atypical brain development and an elevated risk for psychopathology in offspring. Supportive environments during early postnatal life may promote brain development and reverse atypical developmental trajectories induced by prenatal stress. We reviewed studies focused on the role of key early environmental factors in moderating associations between prenatal stress exposure and infant brain and neurocognitive outcomes. Specifically, we focused on the associations between parental caregiving quality, environmental enrichment, social support, and socioeconomic status with infant brain and neurocognitive outcomes. We examined the evidence that these factors may moderate the effects of prenatal stress on the developing brain. Complementing findings from translational models, human research suggests that high-quality early postnatal environments are associated with indices of infant neurodevelopment that have also been associated with prenatal stress, such as hippocampal volume and frontolimbic connectivity. Human studies also suggest that maternal sensitivity and higher socioeconomic status may attenuate the effects of prenatal stress on established neurocognitive and neuroendocrine mediators of risk for psychopathology, such as hypothalamic-pituitary-adrenal axis functioning. Biological pathways that may underlie the effects of positive early environments on the infant brain, including the epigenome, oxytocin, and inflammation, are also discussed. Future research in humans should examine resilience-promoting processes in relation to infant brain development using large sample sizes and longitudinal designs. The findings from this review could be incorporated into clinical models of risk and resilience during the perinatal period and used to design more effective early programs that reduce risk for psychopathology.

Vulnerability to chronic stress and the phenotypic heterogeneity of presbycusis with subjective tinnitus

Age-related functional reserve decline and vulnerability of multiple physiological systems and organs, as well as at the cellular and molecular levels, result in different frailty phenotypes, such as physical, cognitive, and psychosocial frailty, and multiple comorbidities, including age-related hearing loss (ARHL) and/or tinnitus due to the decline in auditory reserve. However, the contributions of chronic non-audiogenic cumulative exposure, and chronic audiogenic stress to phenotypic heterogeneity of presbycusis and/or tinnitus remain elusive. Because of the cumulative environmental stressors throughout life, allostasis systems, the hypothalamus-pituitary-adrenal (HPA) and the sympathetic adrenal-medullary (SAM) axes become dysregulated and less able to maintain homeostasis, which leads to allostatic load and maladaptation. Brain-body communication via the neuroendocrine system promotes systemic chronic inflammation, overmobilization of energetic substances (glucose and lipids), and neuroplastic changes via the non-genomic and genomic actions of glucocorticoids, catecholamines, and their receptors. These systemic maladaptive alterations might lead to different frailty phenotypes and physical, cognitive, and psychological comorbidities, which, in turn, cause and exacerbate ARHL and/or tinnitus with phenotypic heterogeneity. Chronic audiogenic stressors, including aging accompanying ontological diseases, cumulative noise exposure, and ototoxic drugs as well as tinnitus, activate the HPA axis and SAM directly and indirectly by the amygdala, promoting allostatic load and maladaptive neuroplasticity in the auditory system and other vulnerable brain regions, such as the hippocampus, amygdala, and medial prefrontal cortex (mPFC). In the auditory system, peripheral deafferentation, central disinhibition, and tonotopic map reorganization may trigger tinnitus. Cross-modal maladaptive neuroplasticity between the auditory and other sensory systems is involved in tinnitus modulation. Persistent dendritic growth and formation, reduction in GABAergic inhibitory synaptic inputs induced by chronic audiogenic stresses in the amygdala, and increased dendritic atrophy in the hippocampus and mPFC, might involve the enhancement of attentional processing and long-term memory storage of chronic subjective tinnitus, accompanied by cognitive impairments and emotional comorbidities. Therefore, presbycusis and tinnitus are multisystem disorders with phenotypic heterogeneity. Stressors play a critical role in the phenotypic heterogeneity of presbycusis. Differential diagnosis based on biomarkers of metabonomics study, and interventions tailored to different ARHL phenotypes and/or tinnitus will contribute to healthy aging and improvement in the quality of life.

Neurobiology of Maternal Behavior in Nonhuman Mammals: Acceptance, Recognition, Motivation, and Rejection

Among the different species of mammals, the expression of maternal behavior varies considerably, although the end points of nurturance and protection are the same. Females may display passive or active responses of acceptance, recognition, rejection/fear, or motivation to care for the offspring. Each type of response may indicate different levels of neural activation. Different natural stimuli can trigger the expression of maternal and paternal behavior in both pregnant or virgin females and males, such as hormone priming during pregnancy, vagino-cervical stimulation during parturition, mating, exposure to pups, previous experience, or environmental enrichment. Herein, we discuss how the olfactory pathways and the interconnections of the medial preoptic area (mPOA) with structures such as nucleus accumbens, ventral tegmental area, amygdala, and bed nucleus of stria terminalis mediate maternal behavior. We also discuss how the triggering stimuli activate oxytocin, vasopressin, dopamine, galanin, and opioids in neurocircuitries that mediate acceptance, recognition, maternal motivation, and rejection/fear.

DNA methylation as a mediator in the association between prenatal maternal stress and child mental health outcomes: Current state of knowledge

BACKGROUND

Prenatal maternal stress is increasingly recognized as a risk factor for offspring mental health challenges. DNA methylation may be a mechanism, but few studies directly tested mediation. These few integrative studies are reviewed along with studies from three research areas: prenatal maternal stress and child mental health, prenatal maternal stress and child DNA methylation, and child mental health and DNA methylation.

METHODS

We conducted a narrative review of articles in each research area and the few published integrative studies to evaluate the state of knowledge.

RESULTS

Prenatal maternal stress was related to greater offspring internalizing and externalizing symptoms and to greater offspring peripheral DNA methylation of the NR3C1 gene. Youth mental health problems were also related to NR3C1 hypermethylation while epigenome-wide studies identified genes involved in nervous system development. Integrative studies focused on infant outcomes and did not detect significant mediation by DNA methylation though methodological considerations may partially explain these null results.

LIMITATIONS

Operationalization of prenatal maternal stress and child mental health varied greatly. The few published integrative studies did not report conclusive evidence of mediation by DNA methylation.

CONCLUSIONS

DNA methylation likely mediates the association between prenatal maternal stress and child mental health. This conclusion still needs to be tested in a larger number of integrative studies. Key empirical and statistical considerations for future research are discussed. Understanding the consequences of prenatal maternal stress and its pathways of influence will help prevention and intervention efforts and ultimately promote well-being for both mothers and children.

Chimpanzee Extraversion scores vary with epigenetic modification of dopamine receptor gene D2 (DRD2) and early rearing conditions

Chimpanzees have consistent individual differences in behaviour, also referred to as personality. Similar to human personality structure, five dimensions are commonly found in chimpanzee studies that show evidence for convergent and predictive validity (Dominance, Openness, Extraversion, Agreeableness, and Reactivity/Undependability). These dimensions are to some extent heritable, indicating a genetic component that explains part of the variation in personality scores, but are also influenced by environmental factors, such as the early social rearing background of the individuals. In this study, we investigated the role of epigenetic modification of the dopamine receptor D2 gene (DRD2) as a potential mechanism underlying personality variation in 51 captive chimpanzees. We used previously collected personality trait rating data and determined levels of DRD2 CpG methylation in peripheral blood samples for these same individuals. Results showed that DRD2 methylation is most strongly associated with Extraversion, and that varying methylation levels at specific DRD2 sites are associated with changes in Extraversion in nursery-reared, but not mother-reared, individuals. These results highlight the role of dopaminergic signalling in chimpanzee personality, and indicate that environmental factors, such as social experiences early in life, can have long-lasting behavioural effects, potentially through modification of the epigenome. These findings add to the growing evidence demonstrating the importance of the experience-dependent methylome for the development of complex social traits like personality.

NR3C1 gene methylation and cortisol levels in preterm and healthy full-term infants in the first 3 months of life

Aim: To describe NR3C1 exon-1F methylation and cortisol levels in newborns. Materials & methods: Preterm ≤1500 g and full-term infants were included. Samples were collected at birth and at days 5, 30 and 90 (or at discharge). Results: 46 preterm and 49 full-term infants were included. Methylation was stable over time in full-term infants (p = 0.3116) but decreased in preterm infants (p = 0.0241). Preterm infants had higher cortisol levels on the fifth day, while full-term infants showed increasing levels (p = 0.0177) over time. Conclusion: Hypermethylated sites in NR3C1 at birth and higher cortisol levels on day 5 suggest that prematurity, reflecting prenatal stress, affects the epigenome. Methylation decrease over time in preterm infants suggests that postnatal factors may modify the epigenome, but their role needs to be clarified.