Effect of stress gene-by-environment interactions on hippocampal volumes and cortisol secretion in adolescent girls

Unraveling sex differences in maternal and paternal care impacts on social behaviors and neurobiological responses to early-life adversity

Early-life stress (ELS) affects the development of prosocial behaviors and social-cognitive function, often leading to structural brain changes and increased psychosocial disorders. Recent studies suggest that mother- and father-child relationships independently influence social development in a sex-specific manner, but the effects of impaired father-child relationships are often overlooked. This review examines preclinical rodent studies to explore how parental neglect impacts neuroplasticity and social behaviors in offspring. We highlight that disruptions in maternal interactions may affect male pups more in uniparental rodents, while impaired paternal interactions in biparental rodents tend to impact female pups more. Due to limited research, the separate effects of maternal and paternal neglect on brain development and social behaviors in biparental species remain unclear. Addressing these gaps could clarify the sex-specific mechanisms underlying social and neurobiological deficits following parental neglect.

NR3C1 and NR3C2 Genes Increase the Risk of Suicide Attempt in Psychiatric Disorder Patients with History of Childhood Trauma

Background

Hypothalamic-pituitary-adrenal axis gene variants and childhood trauma (CT) are considered risk factors for suicide attempt (SA). The aim of the present study was analyzed gene x environment (GxE) interaction of NR3C1, NR3C2, and CT, and NR3C1 and NR3C2 gene expression in the development of SA with CT.

Participants and Methods

A total of 516 psychiatric Mexican patients from Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz. Among them, 274 had SA at least once and 242 had not SA. Genetic variants of NR3C1 and NR3C2 were genotyped in all the patients, of which were obtained the CT information from medical records. Additionally, the gene expression of NR3C1 and NR3C2 was also analyzed for a subsample of 96 patients, obtaining the TC information from Childhood Trauma Questionnaire (CTQ).

Results

The analysis showed a GxE interaction of NR3C1, NR3C2, and CT (OR=2.8, 95% CI [1.9-3.9], p<0.0001). Interactions were also observed with neglect (OR=2.1, 95% CI [1.4-3.1], p<0.0001), emotional abuse (OR=2.1, 95% CI [1.5-3], p<0.0001), and sexual abuse (OR=2.4, 95% CI [1.4-2.9], p<0.0001) in the prediction of SA. The analysis of gene expression identified an overexpression of NR3C1 in SA patients with high scores for physical and sexual abuse (p<0.0001; p<0.0006, respectively) and emotional neglect (p=0.014). An underexpression was observed of NR3C2, associated with high scores of trauma subtypes (p<0.0001) except physical neglect. Additionally, we observed an overexpression of NR3C1 gene in patients with SA carriers of A allele of rs6191 (p=0.0015). Also, overexpression of NR3C1 gene in carriers of G allele of rs6198 and underexpression of NR3C2 gene in carriers of G allele of rs5522 (p<0.0001).

Conclusion

Our findings suggest that genetic variants of NR3C1 and NR3C2 differentially affect expression levels, increasing the susceptibility to SA in psychiatric patients with a history of CT.

Boophone disticha attenuates five day repeated forced swim-induced stress and adult hippocampal neurogenesis impairment in male Balb/c mice

Depression is one of the most common neuropsychiatric disorders and is associated with dysfunction of the neuroendocrine system and alterations in specific brain proteins. Boophone disticha (BD) is an indigenous psychoactive bulb that belongs to the Amaryllidacae family, which is widely used in Southern Africa to treat depression, with scientific evidence of potent antidepressant-like effects. The present study examined the antidepressant effects of BD and its mechanisms of action by measuring some behavioural parameters in the elevated plus maze, brain content of corticosterone, brain derived neurotropic factor (BDNF), and neuroblast differentiation in the hippocampus of Balb/c mice exposed to the five day repeated forced swim stress (5d-RFSS). Male Balb/c mice were subjected to the 5d-RFSS protocol to induce depressive-like behaviour (decreased swimming, increased floating, decreased open arm entry, decreased time spent in the open arms and decreased head dips in the elevated plus maze test) and treated with distilled water, fluoxetine and BD. BD treatment (10 mg/kg/p.o for 3 weeks) significantly attenuated the 5d-RFSS-induced behavioural abnormalities and the elevated serum corticosterone levels observed in stressed mice. Additionally, 5d-RFSS exposure significantly decreased the number of neuroblasts in the hippocampus and BDNF levels in the brain of Balb/c mice, while fluoxetine and BD treatment attenuated these changes. The antidepressant effects of BD were comparable to those of fluoxetine, but unlike fluoxetine, BD did not show any anxiogenic effects, suggesting better pharmacological functions. In conclusion, our study shows that BD exerted antidepressant-like effects in 5d-RFSS mice, mediated in part by normalizing brain corticosterone and BDNF levels.

Structural brain correlates of childhood trauma with replication across two large, independent community-based samples

INTRODUCTION

Childhood trauma and adversity are common across societies and have strong associations with physical and psychiatric morbidity throughout the life-course. One possible mechanism through which childhood trauma may predispose individuals to poor psychiatric outcomes is via associations with brain structure. This study aimed to elucidate the associations between childhood trauma and brain structure across two large, independent community cohorts.

METHODS

The two samples comprised (i) a subsample of Generation Scotland (n=1,024); and (ii) individuals from UK Biobank (n=27,202). This comprised n=28,226 for mega-analysis. MRI scans were processed using Free Surfer, providing cortical, subcortical, and global brain metrics. Regression models were used to determine associations between childhood trauma measures and brain metrics and psychiatric phenotypes.

RESULTS

Childhood trauma associated with lifetime depression across cohorts (OR 1.06 GS, 1.23 UKB), and related to early onset and recurrent course within both samples. There was evidence for associations between childhood trauma and structural brain metrics. This included reduced global brain volume, and reduced cortical surface area with highest effects in the frontal (β=-0.0385, SE=0.0048, p(FDR)=5.43x10-15) and parietal lobes (β=-0.0387, SE=0.005, p(FDR)=1.56x10-14). At a regional level the ventral diencephalon (VDc) displayed significant associations with childhood trauma measures across both cohorts and at mega-analysis (β=-0.0232, SE=0.0039, p(FDR)=2.91x10-8). There were also associations with reduced hippocampus, thalamus, and nucleus accumbens volumes.

DISCUSSION

Associations between childhood trauma and reduced global and regional brain volumes were found, across two independent UK cohorts, and at mega-analysis. This provides robust evidence for a lasting effect of childhood adversity on brain structure.

Significant age by childhood trauma interactions on grey matter volumes: A whole brain VBM analysis

BACKGROUND

Childhood trauma is deleterious to long term brain development. The changes are variable, and depend on gender, age and the nature of the trauma. In this exploratory analysis, we investigated the effects of exposure to emotional trauma on grey matter (GM) volumes in adolescent females.

METHODS

We explored GM volumes in non-clinical females aged 12-17 years who had been exposed to either higher (HET; N = 75) or minimal (MET; N = 127) emotional trauma. High-resolution T1-weighted structural images were analysed with an optimised FSL-VBM protocol. The General Linear Model was run on HET versus MET with continuous age as an interaction. Mean GM volumes were extracted from significant corrected age interaction statistical maps and scrutinised with SPSS®.

RESULTS

We observed greater HET*age than MET*age interactions (corrected p-value = 0.0002), in 4 separate bilateral cortical regions associated with mood disorders. Scrutiny of these regions showed significant GM volume enlargements in the early adolescent HET group (p = 0.017) and reductions in the late adolescent HET group (p < 0.0001). Notably, there were no differences in middle adolescence (p > 0.05).

LIMITATIONS

Causality cannot be inferred from this cross-sectional study and the onset of trauma cannot be determined using retrospective measures.

CONCLUSIONS

Whilst GM volumes diminish from early adolescence onwards, our results show that HET impacts this brain development, perhaps first via unstable adaptative mechanisms, followed by maladaptive processes in late adolescence. This suggests that compromises of emotional and cognitive self-regulation in mood disorders may underpin the structural abnormalities observed across multiple brain regions in these teenage girls.

The interplay between genetic variation and gene expression of the glucocorticoid receptor gene NR3C1 and blood cortisol levels on verbal memory and hippocampal volumes

The hypothalamus-pituitary-adrenal axis is the main physiological stress response system and regulating the release of cortisol. The two corticoid receptors encoded by the genes NR3C1 and NR3C2 are the main players in regulating the physiological response to cortisol. This biological system has been linked to neurocognitive processes and memory, yet the mechanisms remain largely unclear. In two independent general population studies (SHIP, total sample size > 5500), we aim to diseantangle the effects of genetic variation, gene expression and cortisol on verbal memory and memory associated brain volume. Especially for NR3C1 results exhibited a consistent pattern of direct an interactive effects. All three biological layers, genetic variation (rs56149945), gene expression for NR3C1 and cortisol levels, were directly associated with verbal memory. Interactions between these components showed significant effects on verbal memory as well as hippocampal volume. For NR3C2 such a complex association pattern could not be observed. Our analyses revealed that different components of the stress response system are acting together on different aspects of cognition. Complex phenotypes, such as cognition and memory function are regulated by a complex interplay between different genetic and epigenetic features. We promote the glucocorticoid receptor NR3C1 as a main target to focus in the context of verbal memory and provided a mechanistic concept of the interaction between various biological layers spanning NR3C1 function and its effects on memory. Especially the NR3C1 transcript seemed to be a key element in this complex system.

Going beyond risk factor: Childhood maltreatment and associated modifiable targets to improve life-long outcomes in mood disorders

Childhood maltreatment increases risk for mood disorders and is associated with earlier onset-and more pernicious disease course following onset-of mood disorders. While the majority of studies to date have been cross-sectional, longitudinal studies are emerging and support the devastating role(s) childhood maltreatment has on development of, and illness course in, mood disorders. This manuscript extends prior reviews to emphasize more recent work, highlighting longitudinal data, and discusses treatment studies that provide clues to mechanisms that mediate disease risk, course, relapse, and treatment response. Evidence suggesting systemic inflammation, alterations in hypothalamic-pituitary-adrenal (HPA) axis function and corticotropin-releasing factor (CRF) neural systems, genetic and other familial factors as mechanisms that mediate risk and onset of, and illness course in, mood disorders following childhood maltreatment is discussed. Risky behaviors following maltreatment, e.g., substance use and unhealthy lifestyles, may further exacerbate alterations in the HPA axis, CRF neural systems, and systematic inflammation to contribute to a more pernicious disease course. More research on sex differences and the impact of maltreatment in vulnerable populations is needed. Future research needs to be aimed at leveraging knowledge on modifiable targets, going beyond childhood maltreatment as a risk factor, to inform prevention and treatment strategies and foster trauma-informed care.

FKBP51 modulates hippocampal size and function in post-translational regulation of Parkin

FK506-binding protein 51 (encoded by Fkpb51, also known as Fkbp5) has been associated with stress-related mental illness. To investigate its function, we studied the morphological consequences of Fkbp51 deletion. Artificial Intelligence-assisted morphological analysis revealed that male Fkbp51 knock-out (KO) mice possess more elongated dentate gyrus (DG) but shorter hippocampal height in coronal sections when compared to WT. Primary cultured Fkbp51 KO hippocampal neurons were shown to exhibit larger dendritic outgrowth than wild-type (WT) controls and pharmacological manipulation experiments suggest that this may occur through the regulation of microtubule-associated protein. Both in vitro primary culture and in vivo labeling support a role for FKBP51 in the regulation of microtubule-associated protein expression. Furthermore, Fkbp51 KO hippocampi exhibited decreases in βIII-tubulin, MAP2, and Tau protein levels, but a greater than 2.5-fold increase in Parkin protein. Overexpression and knock-down FKBP51 demonstrated that FKBP51 negatively regulates Parkin in a dose-dependent and ubiquitin-mediated manner. These results indicate a potential novel post-translational regulatory mechanism of Parkin by FKBP51 and the significance of their interaction on disease onset. KO has more flattened hippocampus using AI-assisted measurement Both pyramidal cell layer (PCL) of CA and granular cell layer (GCL) of DG distinguishable as two layers: deep cell layer and superficial layer. Distinct MAP2 expression between deep and superficial layer between KO and WT, Higher Parkin expression in KO brain Mechanism of FKBP51 inhibition resulting in Parkin, MAP2, Tau, and Tubulin expression differences between KO and WT mice, and resulting neurite outgrowth differences.

The Molecular Basis of Resilience: A Narrative Review

Resilience refers to the adaptability of a person - an ability to "bounce-back" from stressors. We question if resilience can be strengthened, potentially to decrease the risk of stress-related disorders. Unfortunately, the molecular origins of resilience are complicated and not yet well understood. In this review, we examine the various physiological biomarkers of resilience, including the associated genes, epigenetic changes, and protein biomarkers associated with resilient phenotypes. In addition to assessing biomarkers that may indicate higher levels of resilience, we also review at length the many biomarkers that confer lower levels of resilience and may lead to disorders of low resilience, such as anxiety and depression. This large and encompassing review may help to identify the possible therapeutic targets of resilience. Hopefully these studies will lead to a future where stress-related disorders can be prevented, rather than treated.

The Interaction Between POMC rs2071345 Polymorphism and Alcohol Dependence in Anxiety Symptoms Among Chinese Male Problem Drinkers

OBJECTIVE

Alcohol dependence can increase the level of anxiety. A growing body of research has identified a link between anxiety symptoms of problem drinkers and their genetic or environment factors, respectively. However, to date few studies have directly examined gene-environment (G × E) interaction on their anxiety symptoms during the acute alcohol withdrawal. The present study aims to examine the interaction between the proopiomelanocortin (POMC) rs2071345 polymorphism and alcohol dependence on anxiety symptoms of male problem drinkers, and further test the exact form of interaction on two competing models: the diathesis-stress model vs. the differential susceptibility model.

METHODS

A total of 440 male problem drinkers (M _age = 44.5 years, SD = 9.45) were recruited from nine main psychiatric hospitals of northern China during acute alcohol withdrawal. Blood samples were collected for genotyping, self-reported anxiety symptoms, and levels of alcohol dependence were assessed.

RESULTS

Results indicated that the POMC rs2071345 polymorphism significantly moderated anxiety symptoms associated with alcohol dependence. A region of significance (RoS) test showed that male problem drinkers with T allele were more likely to experience more anxiety symptoms than those with CC homozygote when the standardized score of concurrent alcohol dependence was above 0.31. Confirmatory model evaluation indicated that the interaction effect involving POMC gene polymorphism conformed to the diathesis-stress model rather than differential-susceptibility model of person × environment interaction.

CONCLUSIONS

This study suggested that the SNP in POMC rs2071345 was associated with alcohol dependence in anxiety symptoms of male problem drinkers and further provided evidence in support of the diathesis-stress hypothesis of alcohol dependence in terms of anxiety symptoms.

Emotional dysregulation mediates the impact of childhood trauma on psychological distress: First Italian data during the early phase of COVID-19 outbreak

BACKGROUND

The coronavirus disease 2019 pandemic represents an unprecedented traumatic stressor to mental health. Psychological distress is considered a reliable proxy for psychopathology and can be negatively influenced by childhood trauma through sensitization effects. Emotion dysregulation has been proposed as a potential mediator of this mechanism. We aimed to test this hypothesis in a national Italian sample assessed in the early phase of the coronavirus disease 2019 outbreak.

METHODS

We investigated the relationship between psychological distress and childhood trauma in 500 healthy participants assessed through a survey-based study, after the coronavirus disease 2019 pandemic lockdown in Italy. Levels of psychological distress and history of childhood trauma were obtained using the Kessler-10 (K10) and the Childhood Trauma Questionnaire, respectively. We used bootstrapped mediation analysis to test the mediator role of emotional dysregulation, measured through the Difficulties in Emotion Regulation Scale, on the effect of childhood trauma on psychological distress.

RESULTS

In total, 190 (38%) reported psychological distress related to the coronavirus disease 2019 outbreak. Individuals with psychological distress experienced more childhood trauma, specifically emotional abuse (F = 23.51, df = 1, p < 0.001) and neglect (F = 10.98, df = 1, p = 0.001). After modelling the effect of emotional dysregulation, the impact of childhood trauma on coronavirus disease 2019-related psychological distress resulted in indirect effects and mediated by deficits in emotion regulation mechanisms (bootstrapped lower level of confidence interval = 0.345, upper level of confidence interval = 0.598).

CONCLUSION

Childhood trauma is associated with increased vulnerability to the stressful effect of the coronavirus disease 2019 outbreak. Our data suggest that emotional dysregulation may represent a dimension mediating the impact of childhood trauma on coronavirus disease 2019-related psychological distress and may be considered as specific target for interventions aiming at empowering resilience.

Predominant polarity and hippocampal subfield volumes in Bipolar disorders

OBJECTIVES

Predominant polarity (PP) is a proposed course specifier for bipolar disorders (BD) based on patient lifetime mood episodes. Hippocampal subfield volumetric changes have been proposed as a neurobiological marker for BD and could be influenced by mood episodes. Our study aimed to test the hypothesis that patients with BD differ in hippocampal subfield volumes according to their PP.

METHODS

We assessed 172 outpatients, diagnosed with BD according to DSM-IV-TR criteria, and 150 healthy control (HC) participants. High-resolution magnetic resonance imaging was performed on all subjects and volumes of all hippocampal subfields were measured using FreeSurfer.

RESULTS

Patients with depressive PP (BD-DP) and with uncertain PP (BD-UP) but not with manic/hypomanic PP (BD-MP) showed a global reduction on all hippocampal subfield volumes with respect to HCs. When directly compared, BD-DP presented with smaller bilateral presubiculum/subiculum volumes than BD-MP.

CONCLUSIONS

Results support the potential utility of PP not only as a clinical but also as a neurobiological specifier of BD.

Impacts of FKBP5 variants on large-scale brain network connectivity in healthy adults

BACKGROUND

FK506 binding protein 5 (FKBP5) rs1360780 polymorphism has been identified as a molecular genetic marker associated with the dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis. The impact of FKBP5 rs1360780 on the large-scale brain network connectivity in healthy adults is still unknown.

METHODS

479 healthy volunteers (age: 20-80years) completed MRI scans, neuropsychological assessments and blood analysis.All subjects were divided into CC, CT and TT genotypes. Within and between network connectivities (10 sub-networks) were calculated using resting state functional MRI (rs-fMRI) data. The genetic effects and gene-gender/age interaction on large-scale network connectivity were explored.

RESULTS

Compared with CC and CT groups, TT group showed increased intra-connectivity in default mode network (DMN) and increased inter-connectivity mainly distributed among the network of DMN, salience network (SAN), dorsal attention network (DAN), ventral attention network (VAN), subcortical network (SUB), and visual network (VIS). Gene-by-gender and gene-by-age interaction were found in inter-connectivity of DAN to VIS and DMN to FPN, respectively. The altered connectivities correlated with anxiety status test score.

LIMITATIONS

Plasma adrenocorticotropic hormone (ACTH) or cortisol were not measured,or else, we could estimate the hypothalamic-pituitary-adrenal (HPA) axis activity which may strengthen our results.

CONCLUSIONS

FKBP5 rs1360780 modulates the large-scale brain network connectivity in healthy adults. TT carriers showed the increased intra- and inter-connectivities mainly distributed among the network of DMN, SAN, DAN, VAN, SUB and VIS.

Interactions of OXTR rs53576 and emotional trauma on hippocampal volumes and perceived social support in adolescent girls

Oxytocin (OXT) is a neuropeptide involved in social behaviour and is sensitive to environmental influences to alter individual vulnerability or resilience to stress resulting in both negative and positive outcomes. The effects of the OXT receptor (OXTR) single nucleotide polymorphism (SNP) rs53576 on hippocampal and amygdala structure and functions in adults are differentially associated with susceptibility to adversity and social behaviours, but this evidence is lacking in healthy adolescents. Adolescence is a developmental period characterised by neurobiological and psychosocial changes resulting in higher susceptibility to mood disorders, particularly among girls. As the brain is highly plastic at this stage, to understand psychosocial and emotional development, clarity of the interactions between rs53576 and adversity on hippocampal and amygdala volumes and social behaviours is needed. In this study, we investigated the interactions between rs53576 and emotional trauma (ET) exposure on hippocampal and amygdala volumes of adolescent girls, and associations with parenting style, perceived social support and bullying behaviour. Based on an unbiased and corrected analytical approach, we found smaller left hippocampal volumes in higher (hET) compared to minimally (mET) exposed AA homozygotes, but no differences in G allele carriers nor in the amygdala. Within the mET AA group, larger volumes were associated with peer perceived social support, but in their hET counterparts, smaller volumes were associated with familial perceived social support. This evidence supports an important role for the hippocampus in social behaviours but extends current knowledge to suggest that hippocampal social behavioural features are contextually dependent on rs53576.

Understanding trauma-induced hippocampal subfield volume changes in the context of age and health. Response to Malhi et al

It is important to integrate findings converging from different perspectives to better contextualize hippocampal subfield changes induced by childhood trauma (CT). Here we integrate Malhi's et al. model on this issue. Understanding the complex neurobiological mechanisms underpinning CT could address the multifaceted nature of resilience to traumatic life experiences that may cause different effects in health and disease.

The Devastating Clinical Consequences of Child Abuse and Neglect: Increased Disease Vulnerability and Poor Treatment Response in Mood Disorders

A large body of evidence has demonstrated that exposure to childhood maltreatment at any stage of development can have long-lasting consequences. It is associated with a marked increase in risk for psychiatric and medical disorders. This review summarizes the literature investigating the effects of childhood maltreatment on disease vulnerability for mood disorders, specifically summarizing cross-sectional and more recent longitudinal studies demonstrating that childhood maltreatment is more prevalent and is associated with increased risk for first mood episode, episode recurrence, greater comorbidities, and increased risk for suicidal ideation and attempts in individuals with mood disorders. It summarizes the persistent alterations associated with childhood maltreatment, including alterations in the hypothalamic-pituitary-adrenal axis and inflammatory cytokines, which may contribute to disease vulnerability and a more pernicious disease course. The authors discuss several candidate genes and environmental factors (for example, substance use) that may alter disease vulnerability and illness course and neurobiological associations that may mediate these relationships following childhood maltreatment. Studies provide insight into modifiable mechanisms and provide direction to improve both treatment and prevention strategies.

The Biology of Human Resilience: Opportunities for Enhancing Resilience Across the Life Span

Recent scientific and technological advances have brought us closer to being able to apply a true biopsychosocial approach to the study of resilience in humans. Decades of research have identified a range of psychosocial protective factors in the face of stress and trauma. Progress in resilience research is now advancing our understanding of the biology underlying these protective factors at multiple phenotypic levels, including stress response systems, neural circuitry function, and immune responses, in interaction with genetic factors. It is becoming clear that resilience involves active and unique biological processes that buffer the organism against the impact of stress, not simply involve a reversal of pathological mechanisms. Here, we provide an overview of recent progress in the field, highlighting key psychosocial milestones and accompanying biological changes during development, and into adulthood and old age. Continued advances in our understanding of psychological, social, and biological determinants of resilience will contribute to the development of novel interventions and help optimize the type and timing of intervention for those most at risk, resulting in a possible new framework for enhancing resilience across the life span.