Epigenetic programming by maternal behavior

Resveratrol alleviates depressive-like behavior via the activation of SIRT1/NF-κB signaling pathway in microglia

BACKGROUND

Currently, the pathogenesis of depression remains poorly understood, leading to many patients receiving ineffective treatment. Resveratrol has demonstrated beneficial effects in the prevention and treatment of depression. However, it remains unknown whether resveratrol administration can counteract depression-like behaviors by regulating the SIRT1/NF-κB signaling pathway.

METHODOLOGY/PRINCIPAL FINDINGS

Male C57BL/6 mice were randomly assigned to a control group, a depression group, and a resveratrol group. The depression model was established using chronic unpredictable mild stress (CUMS) for 5 weeks. Behavioral tests were conducted to assess depressive-like behaviors. The expression levels of SIRT1 and NF-κB in the hippocampus of mice and BV2 microglial cells were measured. After 5 weeks of modeling, the results indicated that mice in the depression group exhibited significant depressive-like behaviors and inhibited activation of the SIRT1/NF-κB signaling pathway. In contrast, resveratrol administration effectively reversed these changes. Results from in vitro experiments showed that LPS stimulation increased microglial activity and downregulated the SIRT1/NF-κB signaling pathway in microglia; however, resveratrol treatment mitigated these effects.

CONCLUSIONS/SIGNIFICANCE

Our findings suggested that resveratrol can alleviate CUMS-induced depression-like behaviors via the activation of the Sirt1/NF-κB pathway in microglia.

Murine maternal microbiome modifies adverse effects of protein undernutrition on offspring neurobehaviour

Protein undernutrition results in impaired growth and neurobehavioural development in children. However, the impact of timing, environmental factors and maternal versus neonatal influences are unclear. Here, using a mouse model of fetal growth restriction where maternal protein intake is limited during pregnancy, we show that adult offspring exhibit cognitive and anxiety-like behavioural abnormalities. Cross-fostering newborn mice to dams previously exposed to either low protein or standard diet reveals that behavioural impairments in adult offspring require diet-induced conditioning of both fetal development and maternal peripartum physiology. Maternal gut microbiome diversity is reduced, maternal immune, milk, and serum metabolomic profiles are altered, and widespread changes in fetal brain transcriptomic and metabolomic profiles are observed, including subsets of microbiome-dependent metabolites. Finally, we show that dam treatment with a cocktail of ten diet- and microbiome-dependent metabolites results in differential effects on fetal development and postnatal behaviour. Our study highlights the impact of prenatal maternal protein undernutrition on offspring neurobehavioural trajectories and the role of the maternal microbiome.

Imprinting disorders as a window to understand pediatric feeding disorders

Imprinting disorders are a group of rare congenital disorders characterized by common clinical features that affect growth, development, metabolism, and shared molecular abnormalities [1]. Patients with these disorders exhibit feeding difficulties and changes in social skills. Pediatric feeding disorders affect approximately 25% of children in the general population but have been difficult to understand and manage globally; indeed, they have traditionally been approached from different professional disciplines, each advocating its own unique method. An interdisciplinary consensus group recently introduced a more integrative definition of pediatric feeding disorders. From this new approach, we hypothesized that the imprinted genes may play an important role in the relationship between feeding and social development. In addition, we hypothesize in this letter that research on imprinting disorders may contribute to a better understanding of pediatric feeding disorders.

The evolving neurobiology of early-life stress

Because early-life stress is common and constitutes a strong risk factor for cognitive and mental health disorders, it has been the focus of a multitude of studies in humans and experimental models. Yet, we have an incomplete understanding of what is perceived as stressful by the developing brain, what aspects of stress influence brain maturation, what developmental ages are particularly vulnerable to stress, which molecules mediate the effects of stress on brain operations, and how transient stressful experiences can lead to enduring emotional and cognitive dysfunctions. Here, we discuss these themes, highlight the challenges and progress in resolving them, and propose new concepts and avenues for future research.

Early adversity and the comorbidity between metabolic disease and psychopathology

Although the co-existence of metabolic and psychiatric disorders in the same individual (comorbidity) is very prevalent, the mechanisms by which these disorders co-occur are poorly understood, but a history of early-life adversity is a common developmental risk factor. Exposure to adverse environments during critical periods of development (e.g. fetal life and infancy) modifies the metabolism and the function of the brain persistently, influencing behaviours that contribute to both metabolic and mental health disarrangements over the life course. We will review molecular and clinical evidence supporting the notion that early adversity is an important risk factor for the comorbidity between metabolic and psychiatric conditions. We will also discuss the possible mechanisms involved: neurometabolic programming, epigenetic alterations and the cumulative effects of altered inflammatory and oxidative pathways linked to early adversity.

The Interplay of Chronic Stress and Cancer: Pathophysiology and Implications for Integrated Care

BACKGROUND

Cancer-associated depression is a multifaceted condition that arises from the interplay of biological, psychological, and social factors in individuals diagnosed with cancer. Understanding this condition involves exploring how cancer and its treatments can precipitate depressive symptoms and the mechanisms behind this association. Chronic stress, inflammation, and immunological responses play a crucial role in the development of both cancer and depression. The objective of this review is to describe and synthesize information on the complex interactions between chronic stress, inflammation, immunological responses, and cancer development. Additionally, it aims to review existing evidence regarding mechanisms such as neurotransmitter imbalances, structural brain changes, and genetic predispositions as key contributors to depression in cancer patients.

RECENT FINDINGS

A comprehensive literature search on Cancer-associated Depression was conducted in electronic databases, including APA PsycINFO, Medline, Google Scholar, Embase, PubMed, Scopus, and Web of Science. The research focused on understanding the potential relationship between stress-induced depression and cancer by examining neurochemical, anatomical, immunological, genetic, and psychological changes. The findings revealed a compilation of both quantitative and qualitative studies on depression in cancer patients. Evidence suggested a potential link between cancer-induced stress and depression, with increased levels of proinflammatory cytokines (such as IL-6) and dysregulation of neurotransmitters, including serotonin, contributing to the onset of depression. Furthermore, studies indicated that antidepressants, along with psychological interventions, were effective in managing depression among cancer patients.

CONCLUSION

This narrative review provides insights into the importance of integrating oncology and mental health services to address the psychosocial needs of cancer patients. Future research should focus on the bidirectional interactions between stress and cancer, aiming to improve cancer care by incorporating mental health support. Addressing the mental health aspects of cancer treatment can significantly enhance patient outcomes and overall quality of life.

Arbovirus Infections and Epigenetic Mechanisms; a Potential Therapeutic Target

Arboviruses are a group of arthropod-borne viral pathogens that pose a significant threat to the public health system. The clinical manifestations associated with these viruses range from self-limiting infections to life-threatening disorders. As a group of systemic viral infections, arboviruses can affect various parts of human organ systems, such as the nervous system. In the nervous system, epigenetic mechanisms are involved in various mechanisms including adult neurogenesis, neuronal-glial differentiation, the regulation of neural behaviour and neural plasticity, as well as other brain functions such as memory, and cognition. Hence, epigenetic deregulation is a key factor in the aetiology of different neurological disorders that highlights the importance of studying the underlying mechanisms and risk factors to introduce effective therapeutic approaches. There is mounting evidence that arboviruses that affect the nervous system take advantage of various mechanisms to modulate epigenetic processes to regulate their life cycles. This phenomenon may affect the nervous system leading to neurotropic arboviral infection-associated neurological disorders. Hence, it is important to understand reciprocal interplays between neurotropic arboviral pathogens and epigenetic processes to better control these disorders. The present review provides an overview of different interactions of arboviruses with epigenetic mechanisms during neurotropic arboviral infections. It uniquely focuses on the interplay between epigenetic modifications and arboviral neurotropism, shedding light on potential therapeutic strategies that have not been comprehensively addressed before. Targeting virus-induced epigenetic alterations, such as miRNA regulation, could lead to novel antiviral therapies aimed at mitigating neuroinflammation and disease severity.

Interplay between prenatal bisphenol exposure, postnatal maternal care, and offspring sex in predicting DNA methylation relevant to anxiety-like behavior in rats

Prenatal exposure to endocrine disrupting chemicals, such as bisphenols, can alter neurodevelopmental trajectories and have a lasting neurobehavioral impact through epigenetic pathways. However, outcomes associated with prenatal bisphenol exposure may also be shaped by the postnatal environment and collectively these environmental effects may be sex-specific. Thus, an integrative research design that includes multiple early life exposures and considers sex differences may be essential for predicting outcomes. In the current study, we use a multivariate approach to examine the contributions of prenatal bisphenol exposure, postnatal maternal care, and offspring sex to variation in DNA methylation of well-studied candidate genes (NR3C1, BDNF, OXTR) in the ventral hippocampus and amygdala of adult Long-Evans rats. Main effects of postnatal maternal care and interactions with prenatal bisphenol exposure were consistently found for DNA methylation within the NR3C1 gene (ventral hippocampus) and within the BDNF and OXTR genes (amygdala). Sex-specific effects were also found across all analyses. Overall, our findings suggest that both early-life factors (prenatal and postnatal) and offspring sex contribute to variation in DNA methylation in genes and brain regions relevant for the expression of anxiety-like behavior. These results highlight the need to consider the brain region-specific effects of multiple exposures in males and females to understand the lasting effects of early environments.

Strengthening Rigor and Reproducibility in Epigenome-Wide Association Studies of Social Exposures and Brain-Based Health Outcomes

PURPOSE OF REVIEW

Studies examining the effects of social factors on the epigenome have proliferated over the last two decades. Social epigenetics research to date has broadly demonstrated that social factors spanning childhood adversity, to neighborhood disadvantage, educational attainment, and economic instability are associated with alterations to DNA methylation that may have a functional impact on health. These relationships are particularly relevant to brain-based health outcomes such as psychiatric disorders, which are strongly influenced by social exposures and are also the leading cause of disability worldwide. However, social epigenetics studies are limited by the many challenges faced by both epigenome-wide association studies (EWAS) and the study of social factors.

FINDINGS

In this manuscript, we provide a framework to achieve greater rigor and reproducibility in social epigenetics research. We discuss current limitations of the social epigenetics field, as well as existing and new solutions to improve rigor and reproducibility. Readers will gain a better understanding of the current considerations and processes that could maximize rigor when conducting social epigenetics research, as well as the technologies and approaches that merit attention and investment to propel continued discovery into the future.

Genetic and epigenetic changes to the glucocorticoid receptor gene (NR3C1) and cognition in major depressive disorder

INTRODUCTION

Many studies have found that hypothalamic-pituitary-adrenal (HPA) axis abnormalities are related to the pathophysiology of major depressive disorder (MDD) and cognitive functioning. Our aim was to assess the influence of genetic polymorphisms and methylation levels in three different promoter regions throughout the glucocorticoid receptor (GR) gene NR3C1 on cognitive performance in MDD. Plausible interactions with childhood adversity and mediation relationships between genetic and epigenetic variables were explored.

MATERIALS AND METHODS

The sample included a total of 64 MDD patients and 82 healthy controls. Child maltreatment and neurocognitive performance were assessed in all participants. HPA negative feedback was analyzed using the dexamethasone suppression test after the administration of 0.25mg of dexamethasone. A total of 23 single-nucleotide polymorphisms were genotyped, and methylation levels at several CpGs in exons 1D, 1F and 1H of the GR gene were measured.

RESULTS

Results show that, beyond the influence of other covariables, NR3C1 single-nucleotide polymorphisms and methylation levels predicted performance in executive functioning and working memory tasks. No significant interactions or mediation relationships were detected.

CONCLUSIONS

Results suggest that genetic variations and epigenetic regulation of the GR gene are relevant factors influencing cognitive performance in MDD and could emerge as significant biomarkers and therapeutic targets in mood disorders and other stress-related disorders.

Parental kynurenine 3-monooxygenase genotype in mice directs sex-specific behavioral outcomes in offspring

BACKGROUND

Disruptions in brain development can impact behavioral traits and increase the risk of neurodevelopmental conditions such as autism spectrum disorder, attention-deficit/hyperactivity disorder (ADHD), schizophrenia, and bipolar disorder, often in sex-specific ways. Dysregulation of the kynurenine pathway (KP) of tryptophan metabolism has been implicated in cognitive and neurodevelopmental disorders. Increased brain kynurenic acid (KYNA), a neuroactive metabolite implicated in cognition and sleep homeostasis, and variations in the Kmo gene, which encodes kynurenine 3-monooxygenase (KMO), have been identified in these patients. We hypothesize that parental Kmo genetics influence KP biochemistry, sleep behavior and brain energy demands, contributing to impairments in cognition and sleep in offspring through the influence of parental genotype and genetic nurture mechanisms.

METHODS

A mouse model of partial Kmo deficiency, Kmo heterozygous (HET-Kmo+/-), was used to examine brain KMO activity, KYNA levels, and sleep behavior in HET-Kmo+/- compared to wild-type control (WT-Control) mice. Brain mitochondrial respiration was assessed, and KP metabolites and corticosterone levels were measured in breast milk. Behavioral assessments were conducted on wild-type offspring from two parental groups: (i) WT-Control from WT-Control parents, (ii) wild-type Kmo (WT-Kmo+/+) from Kmo heterozygous parents (HET-Kmo+/-). All mice were C57Bl/6J background strain. Adult female and male offspring underwent behavioral testing for learning, memory, anxiety-like behavior and sleep-wake patterns.

RESULTS

HET-Kmo+/- mice exhibited reduced brain KMO activity, increased KYNA levels, and disrupted sleep architecture and electroencephalogram (EEG) power spectra. Mitochondrial respiration (Complex I and Complex II activity) and electron transport chain protein levels were impaired in the hippocampus of HET-Kmo+/- females. Breast milk from HET-Kmo+/- mothers increased kynurenine exposure during lactation but corticosterone levels were unchanged. Compared to WT-Control offspring, WT-Kmo+/+ females showed impaired spatial learning, heightened anxiety, reduced sleep and abnormal EEG spectral power. WT-Kmo+/+ males had deficits in reversal learning but no sleep disturbances or anxiety-like behaviors.

CONCLUSIONS

These findings suggest that Kmo deficiency impacts KP biochemistry, sleep behavior, and brain mitochondrial function. Even though WT-Kmo+/+ inherit identical genetic material as WT-Control, their development might be shaped by the parent's physiology, behavior, or metabolic state influenced by their Kmo genotype, leading to phenotypic sex-specific differences in offspring.

Epigenetics in evolution and adaptation to environmental challenges: pathways for disease prevention and treatment

Adaptation to challenging environmental conditions is crucial for the survival/fitness of all organisms. Alongside genetic mutations that provide adaptive potential during environmental challenges, epigenetic modifications offer dynamic, reversible, and rapid mechanisms for regulating gene expression in response to environmental changes in both evolution and daily life, without altering DNA sequences or relying on accidental favorable mutations. The widespread conservation of diverse epigenetic mechanisms - like DNA methylation, histone modifications, and RNA interference across diverse species, including plants - underscores their significance in evolutionary biology. Remarkably, environmentally induced epigenetic alterations are passed to daughter cells and inherited transgenerationally through germline cells, shaping offspring phenotypes while preserving adaptive epigenetic memory. Throughout anthropoid evolution, epigenetic modifications have played crucial roles in: i) suppressing transposable elements and viral genomes intruding into the host genome; ii) inactivating one of the X chromosomes in female cells to balance gene dosage; iii) genetic imprinting to ensure expression from one parental allele; iv) regulating functional alleles to compensate for dysfunctional ones; and v) modulating the epigenome and transcriptome in response to influence from the gut microbiome among other functions. Understanding the interplay between environmental factors and epigenetic processes may provide valuable insights into developmental plasticity, evolutionary dynamics, and disease susceptibility.

Corticotropin-releasing hormone receptor-1 antagonist attenuates visceral hypersensitivity induced by trinitrobenzene sulfonic acid colitis and maternal separation in rats

BACKGROUND

The prevailing paradigm for the etiology of irritable bowel syndrome is that transient noxious events lead to long-lasting sensitization of the neural pain circuit, despite complete resolution of the initiating event. In this study, we tested the hypotheses that (1) the combination of maternal separation (MS) and previous colorectal inflammation induces extensive visceral hypersensitivity in rats and (2) visceral hypersensitivity induced by maternal separation and previous colorectal inflammation in rats is mediated via the corticotropin-releasing hormone receptor-1 (CRH-R1) pathway.

METHODS

Male rat pups were separated from their dams from postnatal day 2 to postnatal day 21. Acute colitis was induced by colorectal administration of trinitrobenzene sulfonic acid (TNBS) or vehicle on postnatal day 8. On postnatal day 50, the visceromotor response was evaluated by electromyography of the abdominal muscle in response to graded (10-80 mmHg) and phasic colorectal distention (CRD) one time. The same experiments were repeated after administration of the selective CRH-R1 antagonist CP-154,526 (20 mg/kg) or vehicle at 45 min before CRD.

RESULTS

Compared with control rats, visceral perception was increased in MS + TNBS rats. MS + TNBS rats showed a significantly larger visceromotor response to phasic CRD with 40 mmHg, 60 mmHg, and 80 mmHg. Compared with vehicle administration in MS + TNBS rats, administration of CP-154,526 significantly attenuated this visceromotor response to CRD with 40 mmHg, 60 mmHg, and 80 mmHg.

CONCLUSIONS

These findings suggest that the combination of previous colitis and early life stress induce visceral hypersensitivity, and that the CRH-R1 pathway may play a role in this sensitization.

Epigenetic Echoes: Bridging Nature, Nurture, and Healing Across Generations

Trauma can impact individuals within a generation (intragenerational) and future generations (transgenerational) through a complex interplay of biological and environmental factors. This review explores the epigenetic mechanisms that have been correlated with the effects of trauma across generations, including DNA methylation, histone modifications, and non-coding RNAs. These mechanisms can regulate the expression of stress-related genes (such as the glucocorticoid receptor (NR3C1) and FK506 binding protein 5 (FKBP5) gene), linking trauma to biological pathways that may affect long-term stress regulation and health outcomes. Although research using model organisms has elucidated potential epigenetic mechanisms underlying the intergenerational effects of trauma, applying these findings to human populations remains challenging due to confounding variables, methodological limitations, and ethical considerations. This complexity is compounded by difficulties in establishing causality and in disentangling epigenetic influences from shared environmental factors. Emerging therapies, such as psychedelic-assisted treatments and mind-body interventions, offer promising avenues to address both the psychological and potential epigenetic aspects of trauma. However, translating these findings into effective interventions will require interdisciplinary methods and culturally sensitive approaches. Enriched environments, cultural reconnection, and psychosocial interventions have shown the potential to mitigate trauma's impacts within and across generations. By integrating biological, social, and cultural perspectives, this review highlights the critical importance of interdisciplinary frameworks in breaking cycles of trauma, fostering resilience, and advancing comprehensive healing across generations.

The Constrained Disorder Principle: Beyond Biological Allostasis

The constrained disorder principle (CDP) defines complex biological systems based on inherent variability. Allostasis refers to the physiological processes that help maintain stability in response to changing environmental demands. Allostatic load describes the cumulative wear and tear on the body resulting from prolonged exposure to stress, and it has been suggested to mediate the relationship between stress and disease. This study presents the concepts of CDP and allostasis while discussing their similarities and differences. We reviewed the current literature on the potential benefits of introducing controlled doses of biological noise into interventions, which may enhance the effectiveness of therapies. The paper highlights the promising role of variability provided by a CDP-based second-generation artificial intelligence system in improving health outcomes.

Rethinking Depression-Beyond Neurotransmitters: An Integrated Psychoneuroendocrineimmunology Framework for Depression's Pathophysiology and Tailored Treatment

It is known that the effectiveness of drug treatment for depression, ammine deficit based, is largely unsatisfactory. In this review, we examine the proposal of a precision therapy has emerged and has received a strong push by the identification of the role of inflammation in depression. However, precision psychiatry risks being caught in the reductionist trap of searching for the molecular switch that resets the whole system and switches off the disease. This is an illusion since the human being is complex and depression is a systemic and variable disorder. In this study, we show the inadequacy of the reductionist paradigm, and, at the same time, illustrate the superiority of the systemic paradigm centered on psychoneuroendocrineimmunology (PNEI). According to the PNEI paradigm, depression is a disease of the whole human being, caused by different sources working together: psychological, biological, and behavioral. This means knowing the biological and psychological history of the subject, identifying relational and biological crisis factors, and building personalized treatments targeting those factors with the tools of medicine and psychology, which are not reducible to the combination of drugs and psychotherapy. Our proposal presents a paradigm shift that is both theoretical and practical, which enables clinicians to assess patients experiencing depression in a unified way and treat them in an integrated manner.

Childhood obsessive-compulsive disorder, epigenetics, and heterochrony: An evolutionary and developmental approach

Childhood obsessive-compulsive disorder (OCD) stems from a bunch of restricted and repetitive behaviors, which are part of normal behavioral repertoire up to the age of 7. The persistence of compulsive-like behaviors after that age is often associated with unique comorbidity patterns, which are age-at-onset dependent and reflect different developmental stages. In particular, OCD synchronically co-occurs with a broad constellation of neurodevelopmental disorders, whereas diachronically it is related to an increased risk of major adult psychoses. Moreover, OCD is associated with trait-like sensory phenomena, suggesting a common disrupted sensorimotor grounding.The present study is aimed at exploring the hypothesis that this specific temporal and comorbidity OCD profile may be due to a developmental heterochronic mechanism of delay in attenuation of ontogenetically early behavioral patterns. The developmental shift of highly evolutionarily conserved behavioral phenotypes might be regulated by epigenetic changes induced by different conditions of sensory unbalance. This evolutionary and developmental model allows capturing childhood OCD in light of the ultimate causes of ritual behavior throughout phylogeny, namely its "homeostatic" function over conditions of unpredictability. Moreover, it may have important clinical implications, as OCD symptoms could represent putative biomarkers of early divergent developmental trajectories, with a pathoplastic effect on course and outcome.

Circulating microRNAs as Potential Biomarkers of Overweight and Obesity in Adults: A Narrative Review

In an obesogenic environment, such as the one we have been experiencing in recent decades, epigenetics provides answers to the relationship between hereditary and environmentally acquired patterns that have significantly contributed to the global rise in obesity prevalence. MicroRNA (miRNA) constitutes a diminutive non-coding small RNA molecule, 20 to 24 nucleotides in length, that functions as a regulator of gene regulation at the post-translational level. Circulating miRNAs (c-miRNAs) have been detected in multiple body fluids, including blood, plasma, serum, saliva, milk from breastfeeding mothers, and urine. These molecules hold significant therapeutic value and serve as extracellular biomarkers in metabolic diseases. They aid in the diagnosis and tracking of therapy responses, as well as dietary and physical habit modifications. Researchers have studied c-miRNAs as potential biomarkers for diagnosing and characterizing systemic diseases in people of all ages and backgrounds since then. These conditions encompass dyslipidemia, type 2 diabetes mellitus (T2DM), cardiovascular risk, metabolic syndrome, cardiovascular diseases, and obesity. This review therefore analyzes the usefulness of c-miRNAs as therapeutic markers over the past decades. It also provides an update on c-miRNAs associated with general obesity and overweight, as well as with the most prevalent pathologies in the adult population. It also examines the effect of different nutritional approaches and physical activity regarding the activity of miRNAs in circulation in adults with overweight or general obesity. All of this is done with the aim of evaluating their potential use as biomarkers in various research contexts related to overweight and obesity in adults.

Maternal behavior promotes resilience to adolescent stress in mice through a microglia-neuron axis

Early life experience modulates resilience to stress in later life. Previous research implicated maternal care as a key mediator of behavioral responses to the adversity in adolescence, but details of molecular mechanisms remain elusive. Here, we show social stress activates transcription factor C/EBPβ in mPFC neurons of adolescent mice, which transcriptionally upregulates Dnm1l and promotes mitochondrial dysfunction, thereby conferring stress susceptibility in adolescent mice. Moreover, different maternal separation differentially regulates adolescent stress susceptibility. Mechanistically, this differential effect depends on maternal behavior-stimulated IGF-1, which inhibits neuronal C/EBPβ through mTORC1-induced C/EBPβ-LIP translation. Furthermore, we identify maternal behavior-stimulated IGF-1 is mainly released from mPFC microglia. Notably, increased maternal care under an environmental enrichment condition or maternal behavior impairment induced by repeated MPOAEsr1+ cells inhibition in dams prevents or promotes stress susceptibility via microglial-to-neuronal IGF-1-C/EBPβ-DRP1 signaling. In this work, these findings have unveiled molecular mechanisms by which maternal behavior promotes stress resilience in adolescents.

Profiling mRNA encoding glucocorticoid receptor α in saliva: Relationship to hair cortisol levels in individuals aged 15-25 years

OBJECTIVE

We assessed levels of mRNA encoding two glucocorticoid receptor (GR) isoforms (GRα and GRβ) in saliva and examined their relationship with hair cortisol levels and dental caries experience.

DESIGN

Adolescents and young adults were assessed for dental caries experience, and hair cortisol was measured by ELISA. RNA was extracted from whole saliva using TRIzol, followed by quantitative real-time PCR analysis of GRα, GRβ, and glyceraldehyde 3-phosphate dehydrogenase (GAPDH).

RESULTS

GRβ mRNA was not detectable in most samples, whereas GRα mRNA was observed in all samples. There were significantly lower levels of GRα mRNA in individuals with elevated hair cortisol levels than in those with normal cortisol levels. Levels of GRα mRNA did not differ significantly in individuals with dental caries experience compared to individuals with no caries experience.

CONCLUSIONS

We identified and quantified mRNA encoding GRα in saliva. Its levels were inversely associated with hair cortisol (a marker of chronic stress). Although caries experience was associated with hair cortisol levels, there was no significant association between GRα levels and caries experience. Chronic stress has been proposed to be associated with reduced expression of GRα and this association appears to hold for GRα mRNA levels in saliva.

Peripheral DNA Methylation of Cortisol- and Serotonin-Related Genes Predicts Hippocampal Volume in a Pediatric Population

Background

Hippocampal volume increases throughout early development and is an important indicator of cognitive abilities and mental health. However, hippocampal development is highly vulnerable to exposures during development, as seen by smaller hippocampal volume and differential epigenetic programming in genes implicated in mental health. However, few studies have investigated hippocampal volume in relation to the peripheral epigenome across development, and even less is known about potential genetic moderators. Therefore, in this study, we explored relationships between hippocampal volume and peripheral DNA methylation of mental health-related genes, specifically NR3C1, FKBP5, and SLC6A4, throughout early development and whether these associations were moderated by age or genotype.

Methods

Bilateral hippocampal volume was computed from T2-weighted images through FreeSurfer, and DNA methylation was measured from saliva using the Illumina MethylationEPIC microarray in a pediatric population (N = 248, females = 112, meanage = 5.13 years, SDage = 3.60 years).

Results

Multiple linear regression and bootstrapping analyses revealed that DNA methylation of NR3C1, FKBP5, and SLC6A4 was associated with hippocampal volume and that these relationships were moderated by age and gene-specific variants.

Conclusions

These findings support the validity of peripheral DNA methylation profiles for indirectly assessing hippocampal volume and development and underscore the importance of genotype and age considerations in research. Therefore, peripheral epigenetic profiles may be a promising avenue for investigating the impacts of early-life stress on brain structure and subsequent mental health outcomes.

Perspective to Practice: Theoretical Frameworks Explaining Intergenerational Trauma, Violence, and Maltreatment and Implications for the Therapeutic Response

Intergenerational trauma, violence, and maltreatment, in which symptoms or experiences of an ancestor's trauma repeat or otherwise manifest in subsequent generations, presents a weighty societal challenge to which a multiplicity of therapeutic intervention strategies have been applied. Theoretical perspectives are antecedent to clinical and social intervention, informing decisions in both policy and practice. However, these frequently remain subliminal or imperceptible in the discourse, resulting in interventions that remain somewhat dislocated from their theoretical foundations. This narrative review seeks to summarize and discuss each of these theories as they apply to intergenerational trauma, violence, and maltreatment, and to reveal their potential association with specific intervention models or approaches. It positions flexibility between theories and the integration of theories as opportunities to reach new and enhanced understandings and to engender distinctive therapeutic interventions. An enriched understanding of the theories explaining intergenerational trauma, violence, and maltreatment, a deeper appreciation for the pertinence of theory for practice, and an incitement to blend theoretical perspectives in unique ways is, herewith, reached.

Sex-Specific Outcomes in a Rat Model of Early-Life Stress Due to Adverse Caregiving

Early parental care is critical for the development of cortico-limbic circuits regulating stress responses and emotional well-being. Conversely, infant maltreatment can increase susceptibility to mood disorders-such as anxiety and depression-and impair stress-coping abilities. Here, we employed the Scarcity-Adversity Model (SAM) in rats, limiting nesting resources from postnatal days 8-12, to examine its effects on maternal and adult offspring behavior. SAM-exposed mothers exhibited fragmented care and increased violence towards pups. By postpartum day (PPD) 13, maternal fecal corticosterone metabolites (FCM) were elevated, indicating heightened stress. At weaning, SAM dams also showed increased anxiety-like behavior in the Elevated Plus Maze (EPM), suggesting significant emotional alterations. In adulthood, SAM-exposed offspring underwent anxiogenic tests. Both male and female SAM offspring showed increased latency to enter open arms and reduced risk-assessment in the EPM, though females displayed anxiolytic-like behavior in the Light-Dark Box. Male SAM rats had reduced locomotion in the Open Field, earlier onset and increased immobility in the Forced Swim, and increased latency to groom in the Sucrose Splash. When exposed to acute stress, male SAM rats had lower FCM levels, consistent with their passive stress reactivity. These findings confirm SAM induces long-lasting, sex-specific changes in risk-taking, novelty responsiveness, and stress reactions, underscoring the importance of early nurturing in promoting well-being and reducing psychopathological risk.

Toward Understanding and Halting Legacies of Trauma

Echoes of natural and anthropogenic stressors not only reverberate within the physiology, biology, and neurobiology of the generation directly exposed to them but also within the biology of future generations. With the intent of understanding this phenomenon, significant efforts have been made to establish how exposure to psychosocial stress, chemicals, over- and undernutrition, and chemosensory experiences exert multigenerational influences. From these studies, we are gaining new appreciation for how negative environmental events experienced by one generation impact future generations. In this review, we first outline the need to operationally define dimensions of negative environmental events in the laboratory and the routes by which the impact of such events are felt through generations. Next, we discuss molecular processes that cause the effects of negative environmental events to be initiated in the exposed generation and then perpetuated across generations. Finally, we discuss how legacies of flourishing can be engineered to halt or reverse multigenerational influences of negative environmental events. In summary, this review synthesizes our current understanding of the concept, causes, and consequences of multigenerational echoes of stress and looks for opportunities to halt them.

Understanding the Influence of Early-Life Stressors on Social Interaction, Telomere Length, and Hair Cortisol Concentration in Homeless Kittens

The early postnatal period is a critical neurodevelopmental stage characterized by rapid neural maturation and is adversely affected by early-life stressors. This study explored the behavioural, physiological, and epigenetic consequences of early-life stress in a population of homeless rescue kittens. This longitudinal study included 50 kittens rescued and placed into foster care by the Prince Edward Island Humane Society. They underwent behavioural testing at 8, 10, and 12 weeks of age. Hair cortisol concentration was measured at 8 weeks and served as a physiological marker of the previous 3 months' cumulative stress response, which, for these kittens, included the late gestation period. A blood sample for relative telomere length measurement was taken at 10-12 weeks to estimate epigenetic changes as young kittens. Data were analyzed with respect to age and performance in all repeated measures tests, status as a stray or a surrender, and the presence of the dam in their foster homes. As expected, the performance of kittens in all tests changed over the 5 weeks of testing. Kittens separated from their mothers exhibited significantly higher hair cortisol concentrations (p = 0.02) and elongated relative telomere lengths (p = 0.04). No correlation was found between hair cortisol concentration and relative telomere lengths (p = 0.99). These results support the need for further study on the effects of epigenetics and early-life stress, both in kittens and across species.

A Taxonomy of Neuroscientific Strategies Based on Interaction Orders

In recent decades, neuroscience has advanced with increasingly sophisticated strategies for recording and analysing brain activity, enabling detailed investigations into the roles of functional units, such as individual neurons, brain regions and their interactions. Recently, new strategies for the investigation of cognitive functions regard the study of higher order interactions-that is, the interactions involving more than two brain regions or neurons. Although methods focusing on individual units and their interactions at various levels offer valuable and often complementary insights, each approach comes with its own set of limitations. In this context, a conceptual map to categorize and locate diverse strategies could be crucial to orient researchers and guide future research directions. To this end, we define the spectrum of orders of interaction, namely, a framework that categorizes the interactions among neurons or brain regions based on the number of elements involved in these interactions. We use a simulation of a toy model and a few case studies to demonstrate the utility and the challenges of the exploration of the spectrum. We conclude by proposing future research directions aimed at enhancing our understanding of brain function and cognition through a more nuanced methodological framework.

Stay social, stay young: a bioanthropological outlook on the processes linking sociality and ageing

In modern human societies, social interactions and pro-social behaviours are associated with better individual and collective health, reduced mortality, and increased longevity. Conversely, social isolation is a predictor of shorter lifespan. The biological processes through which sociality affects the ageing process, as well as healthspan and lifespan, are still poorly understood. Unveiling the physiological, neurological, genomic, epigenomic, and evolutionary mechanisms underlying the association between sociality and longevity may open new perspectives to understand how lifespan is determined in a broader socio/evolutionary outlook. Here we summarize evidence showing how social dynamics can shape the evolution of life history traits through physiological and genetic processes directly or indirectly related to ageing and lifespan. We start by reviewing theories of ageing that incorporate social interactions into their model. Then, we address the link between sociality and lifespan from two separate points of view: (i) considering evidences from comparative evolutionary biology and bioanthropology that demonstrates how sociality contributes to natural variation in lifespan over the course of human evolution and among different human groups in both pre-industrial and post-industrial society, and (ii) discussing the main physiological, neurological, genetic, and epigenetic molecular processes at the interface between sociality and ageing. We highlight that the exposure to chronic social stressors deregulates neurophysiological and immunological pathways and promotes accelerated ageing and thereby reducing lifespan. In conclusion, we describe how sociality and social dynamics are intimately embedded in human biology, influencing healthy ageing and lifespan, and we highlight the need to foster interdisciplinary approaches including social sciences, biological anthropology, human ecology, physiology, and genetics.

Molecular Innovations Shaping Beak Morphology in Birds

The beak, a pivotal evolutionary trait characterized by high morphological diversity and plasticity, has enabled birds to survive mass extinction events and subsequently radiate into diverse ecological niches worldwide. This remarkable ecological adaptability underscores the importance of uncovering the molecular mechanisms shaping avian beak morphology, particularly benefiting from the rapidly advancing archives of genomics and epigenomics. We review the latest advancements in understanding how genetic and epigenetic innovations control or regulate beak development and drive beak morphological adaptation and diversification over the past two decades. We conclude with several recommendations for future endeavors, expanding to more bird lineages, with a focus on beak shape and the lower beak, and conducting functional experiments. By directing research efforts toward these aspects and integrating advanced omics techniques, the complex molecular mechanisms involved in avian beak evolution and morphogenesis will be deeply interpreted.

Multi-omics analysis reveals novel causal pathways in psoriasis pathogenesis

BACKGROUND

To elucidate the genetic and molecular mechanisms underlying psoriasis by employing an integrative multi-omics approach, using summary-data-based Mendelian randomization (SMR) to infer causal relationships among DNA methylation, gene expression, and protein levels in relation to psoriasis risk.

METHODS

We conducted SMR analyses integrating genome-wide association study (GWAS) summary statistics with methylation quantitative trait loci (mQTL), expression quantitative trait loci (eQTL), and protein quantitative trait loci (pQTL) data. Publicly available datasets were utilized, including psoriasis GWAS data from the European Molecular Biology Laboratory-European Bioinformatics Institute and the UK Biobank. Heterogeneity in dependent instruments (HEIDI) test and colocalization analyses were performed to identify shared causal variants, and multi-omics integration was employed to construct potential regulatory pathways.

RESULTS

Our analyses identified significant causal associations between DNA methylation, gene expression, protein abundance, and psoriasis risk. We discovered two pathways involving the long non-coding RNA RP11-977G19.11 and apolipoprotein F (APOF). Methylation at sites cg26804944 and cg02705573 was negatively associated with RP11-977G19.11 expression. Reduced expression of RP11-977G19.11 was linked to increased APOF levels, which were positively associated with a higher risk of psoriasis. Methylation at sites cg00172967, cg00294382, and cg24773560 was positively associated with RP11-977G19.11 expression. Elevated expression of RP11-977G19.11 was associated with decreased APOF levels, reducing the risk of psoriasis. Colocalization analysis highlighted APOF as a key protein in psoriasis pathogenesis. Validation using skin tissue, EBV-transformed lymphocytes data and inflammation-related protein panels confirmed the associations of RP11-977G19.11 and APOF with psoriasis.

CONCLUSIONS

Our multi-omics analysis provides preliminary evidence for potential molecular mechanisms in psoriasis pathogenesis. Through the integration of GWAS and molecular QTL data, we identify candidate pathways that may be relevant to disease biology. While these findings require extensive experimental validation, they offer a framework for future investigations into the molecular basis of psoriasis.

Depletion of the paternal gut microbiome alters sperm small RNAs and impacts offspring physiology and behavior in mice

The paternal environment prior to conception has been demonstrated to influence offspring physiology and behavior, with the sperm epigenome (including noncoding RNAs) proposed as a potential facilitator of non-genetic inheritance. Whilst the maternal gut microbiome has been established as an important influence on offspring development, the impact of the paternal gut microbiome on offspring development, health and behavior is largely unknown. Gut microbiota have major influences on immunity, and thus we hypothesized that they may be relevant to paternal immune activation (PIA) modulating epigenetic inheritance in mice. Therefore, male C57BL/6J mice (F0) were orally administered non-absorbable antibiotics via drinking water in order to substantially deplete their gut microbiome. Four weeks after administration of the antibiotics (gut microbiome depletion), F0 male mice were then mated with naïve female mice. The F1 offspring of the microbiome-depleted males had reduced body weight as well as altered gut morphology (shortened colon length). F1 females showed significant alterations in affective behaviors, including measures of anxiety and depressive-like behaviors, indicating altered development. Analysis of small noncoding RNAs in the sperm of F0 mice revealed that gut microbiome depletion is associated with differential expression of 8 different PIWI-interacting RNAs (piRNAs), each of which has the potential to modulate the expression of multiple downstream gene targets, and thus influence epigenetic inheritance and offspring development. This study demonstrates that the gut-germline axis influences sperm small RNA profiles and offspring physiology, with specific impacts on offspring affective and/or coping behaviors. These findings may have broader implications for other animal species with comparable gut microbiota, intergenerational epigenetics and developmental biology, including humans.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS AND CONCLUSION

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

Invited review: Phenotyping strategies and genetic background of dairy cattle behavior in intensive production systems-From trait definition to genomic selection

Understanding and assessing dairy cattle behavior is critical for developing sustainable breeding programs and management practices. The behavior of individual animals can provide valuable information on their health and welfare status, improve reproductive management, and predict efficiency traits such as feed efficiency and milking efficiency. Routine genetic evaluations of animal behavior traits can contribute to optimizing breeding and management strategies for dairy cattle but require the identification of traits that capture the most important biological processes involved in behavioral responses. These traits should be heritable, repeatable, and measured in noninvasive and cost-effective ways in many individuals from the breeding populations or related reference populations. Although behavior traits are heritable in dairy cattle populations, they are highly polygenic, with no known major genes influencing their phenotypic expression. Genetically selecting dairy cattle based on their behavior can be advantageous because of their relationship with other key traits such as animal health, welfare, and productive efficiency, as well as animal and handler safety. Trait definition and longitudinal data collection are still key challenges for breeding for behavioral responses in dairy cattle. However, the more recent developments and adoption of precision technologies in dairy farms provide avenues for more objective phenotyping and genetic selection of behavior traits. Furthermore, there is still a need to standardize phenotyping protocols for existing traits and develop guidelines for recording novel behavioral traits and integrating multiple data sources. This review gives an overview of the most common indicators of dairy cattle behavior, summarizes the main methods used for analyzing animal behavior in commercial settings, describes the genetic and genomic background of previously defined behavioral traits, and discusses strategies for breeding and improving behavior traits coupled with future opportunities for genetic selection for improved behavioral responses.

Remodeling the Epigenome Through Meditation: Effects on Brain, Body, and Well-being

Epigenetic mechanisms are key processes that constantly reshape genome activity carrying out physiological responses to environmental stimuli. Such mechanisms regulate gene activity without modifying the DNA sequence, providing real-time adaptation to changing environmental conditions. Both favorable and unfavorable lifestyles have been shown to influence body and brain by means of epigenetics, leaving marks on the genome that can either be rapidly reversed or persist in time and even be transmitted trans-generationally. Among virtuous habits, meditation seemingly represents a valuable way of activating inner resources to cope with adverse experiences. While unhealthy habits, stress, and traumatic early-life events may favor the onset of diseases linked to inflammation, neuroinflammation, and neuroendocrine dysregulation, the practice of mindfulness-based techniques was associated with the alleviation of many of the above symptoms, underlying the importance of lifestyles for health and well-being. Meditation influences brain and body systemwide, eliciting structural/morphological changes as well as modulating the levels of circulating factors and the expression of genes linked to the HPA axis and the immune and neuroimmune systems. The current chapter intends to give an overview of pioneering research showing how meditation can promote health through epigenetics, by reshaping the profiles of the three main epigenetic markers, namely DNA methylation, histone modifications, and non-coding RNAs.

Shedding light on DNA methylation and its clinical implications: the impact of long-read-based nanopore technology

DNA methylation is an essential epigenetic mechanism for regulation of gene expression, through which many physiological (X-chromosome inactivation, genetic imprinting, chromatin structure and miRNA regulation, genome defense, silencing of transposable elements) and pathological processes (cancer and repetitive sequences-associated diseases) are regulated. Nanopore sequencing has emerged as a novel technique that can analyze long strands of DNA (long-read sequencing) without chemically treating the DNA. Interestingly, nanopore sequencing can also extract epigenetic status of the nucleotides (including both 5-Methylcytosine and 5-hydroxyMethylcytosine), and a large variety of bioinformatic tools have been developed for improving its detection properties. Out of all genomic regions, long read sequencing provides advantages in studying repetitive elements, which are difficult to characterize through other sequencing methods. Transposable elements are repetitive regions of the genome that are silenced and usually display high levels of DNA methylation. Their demethylation and activation have been observed in many cancers. Due to their repetitive nature, it is challenging to accurately estimate DNA methylation levels within transposable elements using short sequencing technologies. The advantage to sequence native DNA (without PCR amplification biases or harsh bisulfite treatment) and long and ultra long reads coupled with epigenetic states of the DNA allows to accurately estimate DNA methylation levels in transposable elements. This is a big step forward for epigenomic studies, and unsolved questions regarding gene expression and transposable elements silencing through DNA methylation can now be answered.

Linking the gut microbiome to host DNA methylation by a discovery and replication epigenome-wide association study

Microbiome influences multiple human systems, but its effects on gene methylation is unknown. We investigated the relations between gene methylation in blood and the abundance of common gut bacteria profiled by 16s rRNA gene sequencing in two population-based Dutch cohorts: LifeLines-Deep (LLD, n = 616, discovery) and the Netherlands Twin Register (NTR, n = 296, replication). In LLD, we also explored microbial pathways using data generated by shotgun metagenomic sequencing (n = 683). Methylation in both cohorts was profiled in blood samples using the Illumina 450K array. Discovery and replication analysis identified two independent CpGs associated with the genus Eggerthella: cg16586104 (Pmeta-analysis = 3.21 × 10-11) and cg12234533 (Pmeta-analysis = 4.29 × 10-10). We also show that microbiome can mediate the effect of environmental factors on host gene methylation. In this first association study linking epigenome to microbiome, we found and replicated the associations of two CpGs to the abundance of genus Eggerthella and identified microbiome as a mediator of the exposome. These associations are observational and suggest further investigation in larger and longitudinal set-ups.

Effects of Early Stress Exposure on Anxiety-like Behavior and MORC1 Expression in Rats

Exposure to stress during early and late childhood can lead to long-lasting neurobiological and behavioral impairments. Although sensitive periods for stress exposure are well established, less is known about the trajectory of induced alterations throughout development. In this study, we investigated the impact of maternal separation (MS), social isolation, and their combination on anxiety-like behavior and gene expression across developmental stages. Sprague Dawley rats were exposed to one or both stressors and later assessed for anxiety-like behavior in juvenility, adolescence, and adulthood. mRNA levels of Morc1, a gene linked to early-life stress and depression, were measured in the medial prefrontal cortex to assess developmental changes. The results showed that MS had age- and sex-dependent effects on anxiety-like behavior. Juveniles exhibited less anxiety after MS, while adolescents showed more pronounced behavioral changes following social isolation. No behavioral changes were observed in adults. Males exhibited greater anxiety-like behavior than females in adolescence and adulthood, but not in juvenility. Female adults exposed to both MS and social isolation had significantly lower Morc1 expression compared to controls. These findings highlight the dynamic effects of early stress across the lifespan, underscoring the critical role of adolescence and differential stress susceptibility by age and sex.

Maternal obesity may disrupt offspring metabolism by inducing oocyte genome hyper-methylation via increased DNMTs

Maternal obesity has deleterious effects on the process of establishing oocyte DNA methylation; yet the underlying mechanisms remain unclear. Here, we found that maternal obesity disrupted the genomic methylation of oocytes using a high-fat diet (HFD) induced mouse model, at least a part of which was transmitted to the F2 oocytes and livers via females. We further examined the metabolome of serum and found that the serum concentration of melatonin was reduced. Exogenous melatonin treatment significantly reduced the hyper-methylation of HFD oocytes, and the increased expression of DNMT3a and DNMT1 in HFD oocytes was also decreased. These suggest that melatonin may play a key role in the disrupted genomic methylation in the oocytes of obese mice. To address how melatonin regulates the expression of DNMTs, the function of melatonin was inhibited or activated upon oocytes. Results revealed that melatonin may regulate the expression of DNMTs via the cAMP/PKA/CREB pathway. These results suggest that maternal obesity induces genomic methylation alterations in oocytes, which can be partly transmitted to F2 in females, and that melatonin is involved in regulating the hyper-methylation of HFD oocytes by increasing the expression of DNMTs via the cAMP/PKA/CREB pathway.

Genetic Variation of Hypothalamic-Pituitary-Adrenal Axis Activity in Farm Animals and Beyond

BACKGROUND

Many experimental data in several species clearly demonstrate the important genetic contribution to variations in HPA axis activity. The influence of corticosteroid hormones on adaptive processes and on production traits such as growth rate, feed efficiency, carcass composition, and meat quality is a strong impetus to the search for the molecular bases of these differences for efficient genetic selection.

SUMMARY

Three main sources of genetic variability have been documented so far in farm animal species, the adrenal cortex sensitivity to ACTH-regulating corticosteroid hormone production, the bioavailability of corticosteroid hormones and especially corticosteroid-binding globulin capacity, and glucocorticoid receptor function. The effect of single mutations may be dependent on the genetic background, and genetic variation of cortisol levels may have different functional consequences depending on the molecular mechanisms responsible for this change.

KEY MESSAGES

Understanding the genetic basis of HPA axis activity allows the development of genomic tools and breeding technologies aimed at improving adaptive capacity and stress tolerance in farm animals and their use as valuable models for the genetic study of the HPA axis and the correlation with adaptation, metabolism, and other functions regulated by adrenal hormones, and associated pathologies (obesity, cardiovascular, etc.). The next step will be to explore HPA axis variability from a system genetics perspective including the multiple sources of variation and their interactions. This multifactorial approach is a prerequisite to the use of the HPA axis phenotypes in the genetic selection for more productive and robust animals, with a high level of production of quality products.

Reversibility of disturbed pituitary function in pediatric conditions with psychological stressors: implications for clinical practice

The complex communication network between the central nervous system and the hypothalamic-pituitary axis forms the basis of endocrine functional plasticity, which facilitates adaptation to changing internal and external conditions, but also makes it vulnerable to the negative effects of stressful psychological factors. Herein, clinical conditions such as functional hypothalamic amenorrhea, eating disorders, growth faltering, post-traumatic stress disorder, and pubertal disorders that may emerge during childhood or adolescence, their origin possibly including psychological stressors, are analyzed regarding their genetic susceptibility and reversibility of endocrine function. A discussion on the optimization of therapeutic management defined by managing stress and maximizing the degree and rate of reversibility follows.

Differential methylation of OPRK1 in borderline personality disorder is associated with childhood trauma

According to a growing body of neurobiological evidence, the core symptoms of borderline personality disorder (BPD) may be linked to an opioidergic imbalance between the hedonic and stimulatory activity of mu opioid receptors (MOR) and the reward system inhibiting effects of kappa opioid receptors (KOR). Childhood trauma (CT), which is etiologically relevant to BPD, is also likely to lead to epigenetic and neurobiological adaptations by extensive activation of the stress and endogenous opioid systems. In this study, we investigated the methylation differences in the promoter of the KOR gene (OPRK1) in subjects with BPD (N = 47) and healthy controls (N = 48). Comparing the average methylation rates of regulatorily relevant subregions (specified regions CGI-1, CGI-2, EH1), we found no differences between BPD and HC. Analyzing individual CG nucleotides (N = 175), we found eight differentially methylated CG sites, all of which were less methylated in BPD, with five showing highly interrelated methylation rates. This differentially methylated region (DMR) was found on the falling slope (5') of the promoter methylation gap, whose effect is enhanced by the DMR hypomethylation in BPD. A dimensional assessment of the correlation between disease severity and DMR methylation rate revealed DMR hypomethylation to be negatively associated with BPD symptom severity (measured by BSL-23). Finally, analyzing the influence of CT on DMR methylation, we found DMR hypomethylation to correlate with physical and emotional neglect in childhood (quantified by CTQ). Thus, the newly identified DMR may be a biomarker of the risks caused by CT, which likely epigenetically contribute to the development of BPD.

Transgenerational epigenetic self-memory of Dio3 dosage is associated with Meg3 methylation and altered growth trajectories and neonatal hormones

Intergenerational and transgenerational epigenetic effects resulting from conditions in previous generations can contribute to environmental adaptation as well as disease susceptibility. Previous studies in rodent and human models have shown that abnormal developmental exposure to thyroid hormone affects endocrine function and thyroid hormone sensitivity in later generations. Since the imprinted type 3 deiodinase gene (Dio3) regulates sensitivity to thyroid hormones, we hypothesize its epigenetic regulation is altered in descendants of thyroid hormone overexposed individuals. Using DIO3-deficient mice as a model of developmental thyrotoxicosis, we investigated Dio3 total and allelic expression and growth and endocrine phenotypes in descendants. We observed that male and female developmental overexposure to thyroid hormone altered total and allelic Dio3 expression in genetically intact descendants in a tissue-specific manner. This was associated with abnormal growth and neonatal levels of thyroid hormone and leptin. Descendant mice also exhibited molecular abnormalities in the Dlk1-Dio3 imprinted domain, including increased methylation in Meg3 and altered foetal brain expression of other genes of the Dlk1-Dio3 imprinted domain. These molecular abnormalities were also observed in the tissues and germ line of DIO3-deficient ancestors originally overexposed to thyroid hormone in utero. Our results provide a novel paradigm of epigenetic self-memory by which Dio3 gene dosage in a given individual, and its dependent developmental exposure to thyroid hormone, influences its own expression in future generations. This mechanism of epigenetic self-correction of Dio3 expression in each generation may be instrumental in descendants for their adaptive programming of developmental growth and adult endocrine function.

Biospecimens in the HEALthy Brain and Child Development (HBCD) Study: Rationale and protocol

The HEALthy Brain and Child Development (HBCD) Study, a multi-site prospective longitudinal cohort study, will examine human brain, cognitive, behavioral, social, and emotional development beginning prenatally and planned through early childhood. The longitudinal collection of biological samples from over 7000 birthing parents and their children within the HBCD study enables research on pre- and postnatal exposures (e.g., substance use, toxicants, nutrition), and biological processes (e.g., genetics, epigenetic signatures, proteins, metabolites) on neurobehavioral developmental outcomes. The following biosamples are collected from the birthing parent: 1) blood (i.e., whole blood, serum, plasma, buffy coat, and dried blood spots) during pregnancy, 2) nail clippings during pregnancy and one month postpartum, 3) urine during pregnancy, and 4) saliva during pregnancy and at in-person postnatal assessments. The following samples are collected from the child at in-person study assessments: 1) saliva, 2) stool, and 3) urine. Additionally, placenta tissue, cord blood, and cord tissue are collected by a subset of HBCD sites. Here, we describe the rationale for the collection of these biospecimens, their current and potential future uses, the collection protocol, and collection success rates during piloting. This information will assist research teams in the planning of future studies utilizing this collection of biological samples.

Maternal gut-microbiota impacts the influence of intrauterine environmental stressors on the modulation of human cognitive development and behavior

This review examines the longstanding debate of nature and intrauterine environmental challenges that shapes human development and behavior, with a special focus on the influence of maternal prenatal gut microbes. Recent research has revealed the critical role of the gut microbiome in human neurodevelopment, and evidence suggest that maternal microbiota can impact fetal gene and microenvironment composition, as well as immunophysiology and neurochemical responses. Furthermore, intrauterine neuroepigenetic regulation may be influenced by maternal microbiota, capable of having long-lasting effects on offspring behavior and cognition. By examining the complex relationship between maternal prenatal gut microbes and human development, this review highlights the importance of early-life environmental factors in shaping neurodevelopment and cognition.

Genetic Architecture of Immune Cell DNA Methylation in the Rhesus Macaque

Genetic variation that impacts gene regulation, rather than protein function, can have strong effects on trait variation both within and between species. Epigenetic mechanisms, such as DNA methylation, are often an important intermediate link between genotype and phenotype, yet genetic effects on DNA methylation remain understudied in natural populations. To address this gap, we used reduced representation bisulfite sequencing to measure DNA methylation levels at 555,856 CpGs in peripheral whole blood of 573 samples collected from free-ranging rhesus macaques (Macaca mulatta) living on the island of Cayo Santiago, Puerto Rico. We used allele-specific methods to map cis-methylation quantitative trait loci (meQTL) and tested for effects of 243,389 single nucleotide polymorphisms (SNPs) on local DNA methylation levels. Of 776,092 tested SNP-CpG pairs, we identified 516,213 meQTL, with 69.12% of CpGs having at least one meQTL (FDR < 5%). On average, meQTL explained 21.2% of nearby methylation variance, significantly more than age or sex. meQTL were enriched in genomic compartments where methylation is likely to impact gene expression, for example, promoters, enhancers and binding sites for methylation-sensitive transcription factors. In support, using mRNA-seq data from 172 samples, we confirmed 332 meQTL as whole blood cis-expression QTL (eQTL) in the population, and found meQTL-eQTL genes were enriched for immune response functions, like antigen presentation and inflammation. Overall, our study takes an important step towards understanding the genetic architecture of DNA methylation in natural populations, and more generally points to the biological mechanisms driving phenotypic variation in our close relatives.

Mother-child closeness and adolescent structural neural networks: a prospective longitudinal study of low-income families

Mother-child closeness, a mutually trusting and affectionate bond, is an important factor in shaping positive youth development. However, little is known about the neural pathways through which mother-child closeness is related to brain organization. Utilizing a longitudinal sample primarily from low-income families (N = 181; 76% African American youth and 54% female), this study investigated the associations between mother-child closeness at ages 9 and 15 years and structural connectivity organization (network integration, robustness, and segregation) at age 15 years. The assessment of mother-child closeness included perspectives from both mother and child. The results revealed that greater mother-child closeness is linked with increased global efficiency and transitivity, but not with modularity. Specifically, both the mother's and child's reports of closeness at age 15 years predicted network metrics, but report at age 9 years did not. Our findings suggest that mother-child closeness is associated with neural white matter organization, as adolescents who experienced greater mother-child closeness displayed topological properties indicative of more integrated and robust structural networks.

Sibling presence during fostering ameliorates endocrine stress profile changes in a social rodent species (Octodon degus) in a sex-specific manner

During early life, disruption of the parent-offspring bond can substantially impact development of offspring physiology and behavior. In rodents, it has been well-documented that parental separation, reduction in parental care, and cross-fostering can affect development of the endocrine stress response. For social species, however, several social factors may mitigate the stress of cross-fostering, such as remaining with other known adult caregivers or siblings. In this study, we cross-fostered a social rodent species (Octodon degus) with or without their siblings at postnatal day (PND) 8 and measured their endocrine stress response immediately after fostering (PND9) and at weaning (PND28). We found that female singly-fostered offspring displayed elevated baseline cortisol levels and reduced weight gain immediately after fostering. At weaning, female singly-fostered offspring continued to display elevated baseline cortisol levels compared to non-fostered female offspring, while singly-fostered males demonstrated weaker cortisol negative feedback strength compared to male offspring that were not fostered or were fostered with their siblings. These results suggest that sibling presence may help mitigate the stress of fostering, and that future studies should further examine other social conditions that may help reduce developmental consequences of long-term parental bond disruption.

Prenatal Hypoxia Predisposes to Impaired Expression of the chrna4 and chrna7 Genes in Adult Rats without Affecting Acetylcholine Metabolism during Embryonic Development

Previous studies have shown that the combined effect of fetal hypoxia and maternal stress hormones predetermines tendency to nicotine addiction in adulthood. This study in rats aimed to investigate the effect of prenatal severe hypoxia (PSH) on acetylcholine metabolism in the developing brain, as well as on expression of acetylcholine receptors chrna4 and chrna7 in both the developing brain and adult brain structures following nicotine consumption. In the developing brain of PSH rats, no changes were found in the activity of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) or disturbances in the acetylcholine levels. However, decreased chrna4 expression was detected on the day 15 of pregnancy, while elevation in the chrna7 expression was observed on the days 15 and 16 of embryogenesis. In adulthood, the consequences of PSH were manifested as decreased expression of chrna4 in the medial prefrontal cortex (PFC), nucleus accumbens (NAacc), and hypothalamus (HT), decreased expression of chrna7 in the PFC and hippocampus (HPC). Whereas, nicotine consumption did not decrease the expression levels of chrna4 and chrna7 compared to the control group in the adult PSH rats. Thus, prenatal hypoxia predisposes to impaired expression of the chrna4 and chrna7 genes in adult rats without affecting acetylcholine metabolism during embryonic development.

"When does human life begin?" teaching human embryology in the context of the American abortion debate

The Dobbs decision of the United States Supreme Court and the actions of several state legislatures have made it risky, if not outright dangerous, to teach factual material concerning human embryology. At some state universities, for instance, if a professor's lecture is felt to teach or discuss abortion (as it might when teaching about tubal pregnancies, hydatidiform moles, or eneuploidy), that instructor risks imprisonment for up to 14 years (Gyori, 2023). Some states' new censorship rules have thus caused professors to drop modules on abortion from numerous science and humanities courses. In most states, instructors can still teach about human embryonic development and not risk putting their careers or livelihoods in jeopardy. However, even in many of these institutions, students can bring a professor to a disciplinary hearing by claiming that the instructor failed to provide ample trigger warnings on such issues. This essay attempts to provide some strategies wherein human embryology and the ethical issues surrounding it might be taught and students may be given resources to counter unscientific falsehoods about fertilization and human development. This essay provides evidence for teaching the following propositions. Mis-information about human biology and medicine is rampant on the internet, and there are skills that can be taught to students that will help them determine which sites should trusted. This is a skill that needs to be taught as part of science courses.