Dissecting early life stress-induced adolescent depression through epigenomic approach

Electroacupuncture restores maternal separation-induced glutamatergic presynaptic deficits of the medial prefrontal cortex in adulthood

Maternal separation (MS) serves as a critical model of early life stress (ELS) that can lead to mood disorders, such as depression. Our previous studies suggest that MS may disrupt synaptic transmission in adulthood. While electroacupuncture (EA) has demonstrated antidepressant effects in several animal models of stress-induced depression, it remains unclear whether EA can reverse synaptic transmission deficits caused by ELS. In this study, we examined the effects of EA at Baihui (GV20) and Yintang (GV29) on both behavioural deficits and glutamatergic synaptic transmission in Sprague-Dawley rats subjected to MS. First, we showed that EA effectively alleviated anhedonia and despair-like behaviours. Furthermore, our data indicated that EA restored the decrease in presynaptic glutamate release, as evidenced by changes in the frequency of miniature excitatory postsynaptic currents (mEPSCs) and paired-pulse ratios (PPR). Microdialysis results also suggested that EA elevated extracellular glutamate levels. To explore the underlying mechanisms, we performed Western blot analyses on several proteins involved in glutamatergic synaptic transmission. Notably, we found that EA treatment increased the expression of vesicular glutamate transporters (VGLUT1 and VGLUT2) and vesicle-associated release proteins (SNAP25, Syntaxin-1A, and VAMP2) in the medial prefrontal cortex (mPFC) of MS rats. In contrast, EA did not significantly affect most postsynaptic glutamatergic receptors. These findings underscore the significant impact of EA on glutamatergic synaptic transmission, particularly in restoring presynaptic impairments induced by MS in adulthood.

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.

Surface-based analysis of early cortical gyrification and thickness alterations in treatment-Naïve, first-episode depressive patients during emerging adulthood

BACKGROUND

Extensive research, predominantly in adults, has highlighted structural brain variations among patients with major depressive disorder (MDD). However, emerging adults, who undergo significant cortical reshaping and are highly vulnerable to depression, receive relatively little attention, despite reporting a higher prevalence of childhood trauma experiences. This study examines cortical gyrification and thickness in emerging adults with first-episode, treatment-naïve MDD, with the objective of investigating their association with childhood trauma.

METHODS

Eighty-six emerging adults diagnosed with MDD, aged 18 to 25, and eighty-one healthy controls (HCs), underwent T1-MRI scans. We compared the local gyrification index (LGI) and cortical thickness (CT) between the two groups. Subsequently, we examined the relationship between the LGI and CT in clusters showing differences and childhood trauma as well as clinical characteristics in emerging adults with MDD.

RESULTS

Compared to HCs, MDD showed decreased LGI in the bilateral superior frontal cortices (SFC) and CT in the left pericalcarine cortex (PCC), while an increase in CT was observed in the left lateral orbitofrontal cortex (OFC). The reduction in LGI of the right SFC and the decrease in CT of the left PCC are associated with childhood trauma. Notably these brain abnormalities were not significantly associated with depressive and anxiety symptoms, or the duration of illness.

CONCLUSION

Abnormal cortical development observed in emerging adults with first episode depression may act as a predisposing factor for depression, irrespective of clinical manifestations, and may be linked to childhood trauma.

Comprehensive view of suicide: A neuro-immune-endocrine approach

Suicide is defined as the act of a person attempting to take their own life by causing death. Suicide is a complex phenomenon that is influenced by a multitude of factors, including psychosocial, cultural, and religious aspects, as well as genetic, biochemical, and environmental factors. From a biochemical perspective, it is crucial to consider the communication between the endocrine, immune, and nervous systems when studying the etiology of suicide. Several pathologies involve the bidirectional communication between the peripheral activity and the central nervous system by the action of molecules such as cytokines, hormones, and neurotransmitters. These humoral signals, when present in optimal quantities, are responsible for maintaining physiological homeostasis, including mood states. Stress elevates the cortisol and proinflammatory cytokines levels and alter neurotransmitters balance, thereby increasing the risk of developing a psychiatric disorder and subsequently the risk of suicidal behavior. This review provides an integrative perspective about the neurochemical, immunological, and endocrinological disturbances associated with suicidal behavior, with a particular focus on those alterations that may serve as potential risk markers and/or indicators of the state preceding such a tragic act.

Methylome-wide association study of adolescent depressive episode with psychotic symptoms and childhood trauma

BACKGROUND

Emerging evidence suggests that DNA methylation is crucial in the mental disorder pathophysiology. The current study attempted to identify the dysregulation of DNA methylation patterns in adolescent patients suffering from depressive episodes (DE) while considering the impact of various subtypes, including psychotic symptoms and a history of childhood trauma.

METHODS

The study included 67 patients with DE and 30 healthy controls (HCs) subjects. Severe depressive episode (SDE) patients were grouped according to psychotic symptoms, such as SDE with vs. SDE without psychotic symptoms (cases 29 vs. 21). The Childhood Trauma Questionnaire-Short Form helped assess childhood trauma among all patients. Thus, all the patients were divided into adolescent DE experiencing ≥ two trauma types vs. experiencing ≤ one trauma type (cases, 50 vs. 17). Methylome-wide analysis was conducted on peripheral blood to identify methylation differences in CpG sites for three comparisons: DE vs. HCs, SDE patients with vs. without psychotic symptoms, and DE patients having 0-1 type of childhood trauma vs. those having ≥two types of childhood trauma.

RESULTS

Adolescent DE patients demonstrated a predominant trend of lower methylation levels than HCs, with 259 hypermethylated and 3956 hypomethylated sites. Differentially hypomethylated sites involve related genes such as FKBP5, BDNF, NR3C1, GABRB3, SHANK1, SLC38A1, SLC6A18, CHRNB1, CTNNA2, CTTNBP2, etc. All these genes could be involved in DE pathogenesis. Significant DNA methylation differences could be observed in SDE subgroups with and without psychotic symptoms (e.g., genes like DTNB, CNTN1, CTNNA2), along with those DE patients having 0-1 type of childhood trauma compared to those with ≥2 types (e.g., VWA3B, SYT10, SDK2, CAMSAP3). Many significant methylated sites were associated with genes involved in brain development, highlighting the potential pathophysiological mechanisms linked with DE and its subtypes, such as psychotic symptoms and childhood trauma.

CONCLUSION

Our findings suggest that differential DNA methylation is associated with the pathophysiology of DE, as well as the presence of psychotic symptoms and a history of childhood trauma. These blood-based methylation patterns may serve as biomarkers for DE and shed light on underlying mechanisms across these subtypes.

Self-reported workplace bullying and subsequent risk of diagnosed mental disorders and psychotropic drug prescriptions: A register-based prospective cohort study of 75,252 participants

BACKGROUND

Evidence concerning workplace bullying as a risk factor for mental disorders is currently limited to depressive disorders and mainly based on non-clinical assessments. This study aims to examine the prospective association of self-reported workplace bullying with different types of register-based hospital-diagnosed mental disorders and redeemed psychotropic drug prescriptions.

METHODS

Using a cohort study design, we examined a pooled dataset of 75,252 participants from 14 questionnaire-based surveys conducted between 2004 and 2014. In the questionnaires, workplace bullying was measured by a single item. The questionnaires were linked to Danish registers on hospital-diagnosed mental disorders and redeemed psychotropic drug prescriptions up to 2016. Data were analysed by multivariate Cox proportional hazard models, including only participants without a history of mental disorders or prescriptions since 1995.

RESULTS

After adjustment for sex, age, marital and socio-economic status, workplace bullying was associated with an excess risk of any mental disorder (HR 1.37; 95 % CI: 1.17-1.59) as well as mood disorders and neurotic, stress-related, and somatoform disorders. In stratified analyses, this association were statistically significant only among women. Workplace bullying was also associated with any psychotropic drug prescription (fully-adjusted HR 1.43; 95 % CI: 1.35-1.53). This association was observed in both sexes and for all prescriptions, including anxiolytics, hypnotics and sedatives, antidepressants, and nootropics.

LIMITATIONS

Firm conclusions about sex-related differences cannot be drawn. Residual confounding by unmeasured factors such as personality cannot be ruled out.

CONCLUSIONS

Workplace bullying was associated with higher risks of diagnosed mental disorders among women and psychotropic drug prescriptions in both sexes.

Fluoxetine treatment reverses chronic stress-induced promotion on Fk506-binding protein 5 expression and multiple effects on glucocorticoid receptor phosphorylation in the paraventricular nucleus of mice

BACKGROUND

Fluoxetine is widely used as a first-line antidepressant. However, the molecular mechanisms for its antidepressant effects are still not fully understood. Hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis is a core pathogenic mechanism contributing to depression, and fluoxetine treatment prevents this dysfunction. The glucocorticoid receptor (GR) is a major negative feedback regulator of the HPA axis, while Fk506-binding protein 5 (Fkbp5) is a negative regulator of the GR signaling. Therefore, we examined the effects of fluoxetine on Fkbp5 and the GR signaling in the hypothalamic paraventricular nucleus (PVN) of depressed mice.

METHODS

Mice were exposed to chronic social defeat stress (CSDS), chronic unpredictable mild stress (CUMS), or chronic restraint stress (CRS) with or without fluoxetine treatment (intraperitoneally injected, 20 mg/kg) and examined for changes in depression-like behaviors and HPA axis activity as well as Fkbp5 expression and GR phosphorylation in the PVN. We then examined if adeno-associated virus (AAV)-mediated Fkbp5 overexpression in the PVN affected the antidepressant actions of fluoxetine in mice.

RESULTS

Fluoxetine treatment significantly mitigated CSDS-, CUMS-, and CRS-induced depression-like behaviors and HPA axis hyperactivity in mice. Subsequent western blotting analyses showed that fluoxetine treatment fully reversed not only chronic stress-induced upregulation of Fkbp5 and CRH but also chronic stress-induced increase in Ser203 phosphorylation and decrease in Ser211 and Ser234 phosphorylation in GR in the PVN. Moreover, quantitative real-time reverse transcription PCR (qRT-PCR) analyses revealed that the enhanced mRNA levels of Fkbp5 and CRH in PVN neurons of mice subjected to CSDS/CUMS/CRS were also notably reversed by fluoxetine administration. Conversely, Fkbp5 overexpression in the PVN significantly eliminated the antidepressant effects of fluoxetine in mice without affecting their locomotor activity.

CONCLUSION

These results together suggest that fluoxetine treatment reverses chronic stress-induced promotion on Fkbp5 expression and multiple effects on GR phosphorylation in the PVN of mice.

SIGNIFICANCE STATEMENT

The selective serotonin reuptake inhibitor fluoxetine (sold as Prozac) is a widely used treatment for depression, but the full spectrum of therapeutic mechanisms is still debated. Recent evidence suggests that these therapeutic mechanisms include suppression of chronic stress-activated hypothalamus-pituitary-adrenal (HPA) axis. The current study presents the first in vivo evidence showing that suppression of HPA axis hyperactivity by fluoxetine treatment involves reversal of glucocorticoid receptor (GR) phosphorylation via modulation of the GR negative regulator Fk506-binding protein 5 (Fkbp5) in the hypothalamic paraventricular nucleus (PVN). Fluoxetine treatment not only inhibited chronic stress-induced depression-like behaviors and HPA axis hyperactivity but also reversed Fkbp5 upregulation and GR phosphorylation changes in the PVN, while adeno-associated virus (AAV)-based Fkbp5 overexpression in the PVN eliminated the antidepressant effects of fluoxetine. These findings may expand our understanding of the pharmacological effects of fluoxetine, and further identify Fkbp5 as a possible target for novel antidepressants.

Retrotransposons and the brain: Exploring a complex relationship between mobile elements, stress, and neurological health

Environmental experiences during early life, including stress, can significantly impact brain development and behavior. Early life stress (ELS) is linked to an increased risk for various psychiatric disorders including anxiety, depression, and substance use disorders. Epigenetic mechanisms have increasingly been of interest to understand how environmental factors contribute to reprogramming the brain and alter risk and resilience to developing psychiatric disorders. However, we know very little about mobile elements or the regulation of mobile elements and their contribution to psychiatric disorders. Recently, advances in genomics have contributed to our understanding of mobile elements, including the retrotransposon LINE-1 (L1) and their potential role in mediating environmental experiences. Yet we still do not understand how these elements may contribute to psychiatric disorders. Future research leveraging cutting-edge technologies will deepen our understanding of these mobile elements. By elucidating their role in development and how stress may impact them, we may unlock new avenues for therapeutic and diagnostic innovations.

Activation of somatostatin neurons in the medial amygdala reverses long-term aggression and social deficits associated to early-life stress in male mice

Early postnatal development is a critical period for the configuration of neural networks that support social and affective-like behaviors. In this sense, children raised in stressful environments are at high risk to develop maladaptive behaviors immediately or later in life, including anti-social and aggressive behaviors. However, the neurobiological bases of such phenomena remain poorly understood. Here we showed that, at long-term, maternal separation with early weaning (MSEW) decreased the density of somatostatin-expressing (SST+) neurons in the basolateral amygdala (BLA) of females and males, while their activity was only reduced in the medial amygdala (MeA) of males. Interestingly, only MSEW males exhibited long-term behavioral effects, including reduced sociability and social novelty preference in the 3-chamber test (3CH), decreased social interest in the resident-intruder test (RI), and increased aggressivity in both the RI and the tube dominance test (TT). To test whether the manipulation of MeASST+ neurons was sufficient to reverse these negative behavioral outcomes, we expressed the chemogenetic excitatory receptor hM3Dq in MSEW adult males. We found that the activation of MeASST+ neurons ameliorated social interest in the RI test and reduced aggression traits in the TT and RI assays. Altogether, our results highlight a role for MeASST+ neurons in the regulation of aggressivity and social interest and point to the loss of activity of these neurons as a plausible etiological mechanism linking early life stress to these maladaptive behaviors in later life.

Preliminary Evidence for Neuronal Dysfunction Following Adverse Childhood Experiences: An Investigation of Salivary MicroRNA Within a High-Risk Youth Sample

Background/Objectives: Adverse childhood experiences (ACEs) are potent drivers of psychopathology and neurological disorders, especially within minoritized populations. Nonetheless, we lack a coherent understanding of the neuronal mechanisms through which ACEs impact gene expression and, thereby, the development of psychopathology. Methods: This observational pilot study used a novel marker of neuronal functioning (brain-derived micro ribonucleic acids, or miRNAs) collected via saliva to explore the connection between ACEs and neuronal gene expression in 45 adolescents with a collectively high ACE exposure (26 males and 19 females of diverse races/ethnicities, with six cumulative ACEs on average). We aimed to determine the feasibility of using salivary microRNA for probing neuronal gene expression with the goal of identifying cellular processes and genetic pathways perturbed by childhood adversity. Results: A total of 274 miRNAs exhibited reliable salivary expression (raw counts > 10 in > 10% of samples). Fourteen (5.1%) were associated with cumulative ACE exposure (p < 0.05; r's ≥ 0.31). ACE exposure correlated negatively with miR-92b-3p, 145a-5p, 31-5p, and 3065-5p, and positively with miR-15b-5p, 30b-5p, 30c-5p, 30e-3p, 199a-3p, 223-3p, 338-3p, 338-5p, 542-3p, and 582-5p. Most relations remained significant after controlling for multiple comparisons and potential retrospective bias in ACE reporting for miRNAs with particularly strong relations (p < 0.03). We examined KEGG pathways targeted by miRNAs associated with total ACE scores. Results indicated putative miRNA targets over-represented 47 KEGG pathways (adjusted p < 0.05) involved in neuronal signaling, brain development, and neuroinflammation. Conclusions: Although preliminary and with a small sample, the findings represent a novel contribution to the understanding of how childhood adversity impacts neuronal gene expression via miRNA signaling.

Transcriptome dynamics in mouse amygdala under acute and chronic stress revealed by thiol-labeled RNA sequencing

Both acute and chronic stress have significant impact on brain functions. The amygdala is essential in mediating stress responses, but how its transcriptomic dynamics change under stress remains elusive. To overcome the difficulties in detecting subtle stress-induced changes by evaluating total RNA using classic RNA sequencing, we conducted thiol-labeled RNA sequencing (SLAM-seq). We injected 4-thiouridine (4sU) into mouse amygdala followed by SLAM-seq to detect nascent mRNA induced by acute and chronic restraint stress, and found that SLAM-seq could label actively transcribed genes in the major neuronal and glial subtypes. Using SLAM-seq, we found that chronic stress led to higher turnover of a group of genes associated with myelination, and this finding is confirmed by immunostaining which showed increased myelination in the chronically stressed amygdala. Additionally, genes detected by SLAM-seq and RNA-seq only partially overlapped, suggesting that SLAM-seq and RNA-seq are complementary in identifying stress-responsive genes. By applying SLAM-seq in vivo, we obtained a rich dataset of genes with higher turnover in the amygdala under stress.

Genetic association between post-traumatic stress disorder and cardiovascular disease: A scoping review

INTRODUCTION

Post-traumatic stress disorder (PTSD) is a complex psychiatric disorder associated with adverse long-term health outcomes, including cardiovascular disease (CVD). Despite growing evidence that PTSD is positively associated with CVD, the biological mechanisms underlying this association are poorly understood. This review provides an overview of the current state of science on the genetic association between PTSD and CVD.

MATERIAL AND METHODS

This scoping review identified studies from Pubmed, Embase, PsycINFO, and Web of Science. The search terms were a combination of PTSD, CVD/CVD-related traits, and a set of genetic molecules and related terms. This review followed the PRISMA Extension for Scoping Reviews guidelines. Eligible criteria included original studies that have genetic factors related to PTSD or CVD, conducted in humans, written in English, and published between 2003 and 2023 in peer-reviewed journals.

RESULTS

A total of twenty-three studies were included; PTSD correlated with genetic variants in CVD-related traits and gene expression in regulatory pathways contributing to CVD development. Common CVD-related traits involved in genetic associations with PTSD were inflammation, cellular aging, increased blood pressure, hypothalamus-pituitary-adrenal axis dysregulation, metabolic syndrome, and oxidative stress. These traits may explain potential underlying mechanisms between PTSD and CVD. Evidence of a causal relationship between the two diseases was insufficient.

DISCUSSION

PTSD and CVD/CVD-related traits are genetically associated. Further research is needed to comprehensively explore gene-environment interactions and the cumulative impact of behavioral and psychological factors on the pathophysiological mechanisms between PTSD and CVD.

Enduring Neurobiological Consequences of Early-Life Stress: Insights from Rodent Behavioral Paradigms

Stress profoundly affects physical and mental health, particularly when experienced early in life. Early-life stress (ELS) encompasses adverse childhood experiences such as abuse, neglect, violence, or chronic poverty. These stressors can induce long-lasting changes in brain structure and function, impacting areas involved in emotion regulation, cognition, and stress response. Consequently, individuals exposed to high levels of ELS are at an increased risk for mental health disorders like depression, anxiety, and post-traumatic stress disorders, as well as physical health issues, including metabolic disorders, cardiovascular disease, and cancer. This review explores the biological and psychological consequences of early-life adversity paradigms in rodents, such as maternal separation or deprivation and limited bedding or nesting. The study of these experimental models have revealed that the organism's response to ELS is complex, involving genetic and epigenetic mechanisms, and is associated with the dysregulation of physiological systems like the nervous, neuroendocrine, and immune systems, in a sex-dependent fashion. Understanding the impact of ELS is crucial for developing effective interventions and preventive strategies in humans exposed to stressful or traumatic experiences in childhood.

Early Life Stress and Major Depressive Disorder-An Update on Molecular Mechanisms and Synaptic Impairments

Early life stress (ELS), characterized as abuse, neglect, and abandonment, can cause several adverse consequences in the lives of affected individuals. ELS experiences can affect an individual's development in variable ways, persisting in the long term and promoting lasting impacts, considering that early exposure to stressors can be biologically incorporated, as prolonged stimulation of stress response systems affects the development of the brain structure and other body systems, increasing the risk of diseases associated with stress and cognitive impairment. This type of stress increases the risk of developing major depressive disorder (MDD) in a severe form that does not respond adequately to traditional antidepressant treatments. Several alterations are studied as mechanisms that relate ELS with MDD, such as epigenetic alterations, neurotransmitters, and neuronal signaling. This review discusses research that brings evidence about the ELS mechanisms involved in synaptic impairments and MDD. The processes involved in epigenetic changes and the HPA axis are highlighted, as well as changes in neurotransmitters and neuronal signaling mechanisms.

Deciphering Depression: Epigenetic Mechanisms and Treatment Strategies

Depression, a significant mental health disorder, is under intense research scrutiny to uncover its molecular foundations. Epigenetics, which focuses on controlling gene expression without altering DNA sequences, offers promising avenues for innovative treatment. This review explores the pivotal role of epigenetics in depression, emphasizing two key aspects: (I) identifying epigenetic targets for new antidepressants and (II) using personalized medicine based on distinct epigenetic profiles, highlighting potential epigenetic focal points such as DNA methylation, histone structure alterations, and non-coding RNA molecules such as miRNAs. Variations in DNA methylation in individuals with depression provide opportunities to target genes that are associated with neuroplasticity and synaptic activity. Aberrant histone acetylation may indicate that antidepressant strategies involve enzyme modifications. Modulating miRNA levels can reshape depression-linked gene expression. The second section discusses personalized medicine based on epigenetic profiles. Analyzing these patterns could identify biomarkers associated with treatment response and susceptibility to depression, facilitating tailored treatments and proactive mental health care. Addressing ethical concerns regarding epigenetic information, such as privacy and stigmatization, is crucial in understanding the biological basis of depression. Therefore, researchers must consider these issues when examining the role of epigenetics in mental health disorders. The importance of epigenetics in depression is a critical aspect of modern medical research. These findings hold great potential for novel antidepressant medications and personalized treatments, which would significantly improve patient outcomes, and transform psychiatry. As research progresses, it is expected to uncover more complex aspects of epigenetic processes associated with depression, enhance our comprehension, and increase the effectiveness of therapies.

Subregion-specific transcriptomic profiling of rat brain reveals sex-distinct gene expression impacted by adolescent stress

Stress during adolescence clearly impacts brain development and function. Sex differences in adolescent stress-induced or exacerbated emotional and metabolic vulnerabilities could be due to sex-distinct gene expression in hypothalamic, limbic, and prefrontal brain regions. However, adolescent stress-induced whole-genome expression changes in key subregions of these brain regions were unclear. In this study, female and male adolescent Sprague Dawley rats received one-hour restraint stress daily from postnatal day (PD) 32 to PD44. Corticosterone levels, body weights, food intake, body composition, and circulating adiposity and sex hormones were measured. On PD44, brain and blood samples were collected. Using RNA-sequencing, sex-specific differences in stress-induced differentially expressed (DE) genes were identified in subregions of the hypothalamus, limbic system, and prefrontal cortex. Canonical pathways reflected well-known sex-distinct maladies and diseases, substantiating the therapeutic potential of the DE genes found in the current study. Thus, we proposed specific sex distinct, adolescent stress-induced transcriptional changes found in the current study as examples of the molecular bases for sex differences witnessed in stress induced or exacerbated emotional and metabolic disorders. Future behavioral studies and single-cell studies are warranted to test the implications of the DE genes identified in this study in sex-distinct stress-induced susceptibilities.

Advances in biosensors for major depressive disorder diagnostic biomarkers

Depression is one of the most common mental disorders and is mainly characterized by low mood or lack of interest and pleasure. It can be accompanied by varying degrees of cognitive and behavioral changes and may lead to suicide risk in severe cases. Due to the subjectivity of diagnostic methods and the complexity of patients' conditions, the diagnosis of major depressive disorder (MDD) has always been a difficult problem in psychiatry. With the discovery of more diagnostic biomarkers associated with MDD in recent years, especially emerging non-coding RNAs (ncRNAs), it is possible to quantify the condition of patients with mental illness based on biomarker levels. Point-of-care biosensors have emerged due to their advantages of convenient sampling, rapid detection, miniaturization, and portability. After summarizing the pathogenesis of MDD, representative biomarkers, including proteins, hormones, and RNAs, are discussed. Furthermore, we analyzed recent advances in biosensors for detecting various types of biomarkers of MDD, highlighting representative electrochemical sensors. Future trends in terms of new biomarkers, new sample processing methods, and new detection modalities are expected to provide a complete reference for psychiatrists and biomedical engineers.

DNA Methylation of PXDN Is Associated with Early-Life Adversity in Adult Mental Disorders

Early-life adversity (ELA) is characterized by exposure to traumatic events during early periods of life, particularly involving emotional, sexual and/or physical adversities during childhood. Mental disorders are strongly influenced by environmental and lifestyle-related risk factors including ELA. However, the molecular link between ELA and the risk of an adult mental disorder is still not fully understood. Evidence is emerging that long-lasting changes in the epigenetic processes regulating gene expression, such as DNA methylation, play an important role in the biological mechanisms linking ELA and mental disorders. Based on a recent study, we analyzed the DNA methylation of a specific CpG site within the gene PXDN-cg10888111-in blood in the context of ELA across a set of psychiatric disorders, namely Borderline Personality Disorder (BPD), Major Depressive Disorder (MDD) and Social Anxiety Disorder (SAD), and its potential contribution to their pathogenesis. We found significant hypermethylation in mentally ill patients with high levels of ELA compared to patients with low levels of ELA, whereas cg10888111 methylation in healthy control individuals was not affected by ELA. Further investigations revealed that this effect was driven by the MDD cohort. Providing a direct comparison of cg10888111 DNA methylation in blood in the context of ELA across three mental disorders, our results indicate the role of PXDN regulation in the response to ELA in the pathogenesis of mental disorders, especially MDD. Further studies will be needed to validate these results and decipher the corresponding biological network that is involved in the transmission of ELA to an adult mental disorder in general.

Transgenerational hormesis in healthy aging and antiaging medicine from bench to clinics: Role of food components

Neurodegenerative diseases have multifactorial pathogenesis, mainly involving neuroinflammatory processes. Finding drugs able to treat these diseases, expecially because for most of these diseases there are no effective drugs, and the current drugs cause undesired side effects, represent a crucial point. Most in vivo and in vitro studies have been concentrated on various aspects related to neurons (e.g. neuroprotection), however, there has not been focus on the prevention of early stages involving glial cell activation and neuroinflammation. Recently, it has been demonstrated that nutritional phytochemicals including polyphenols, the main active constituents of the Mediterranean diet, maintain redox balance and neuroprotection through the activation of hormetic vitagene pathway. Recent lipidomics data from our laboratory indicate mushrooms as strong nutritional neuronutrients with strongly activity against neuroinflammation in Meniere' diseaseas, a model of cochleovestibular neural degeneration, as well as in animal model of traumatic brain injury, or rotenone induced parkinson's disease. Moreover, Hidrox®, an aqueous extract of olive containing hydroxytyrosol, and Boswellia, acting as Nrf2 activators, promote resilience by enhancing the redox potential, and thus, regulate through hormetic mechanisms, cellular stress response mechanisms., Thus, modulation of cellular stress pathways, in particular vitagenes system, may be an innovative approach for therapeutic intervention in neurodegenerative disorders.

Perinatal stress modulates glutamatergic functional connectivity: A post-synaptic density immediate early gene-based network analysis

Early life stress may induce synaptic changes within brain regions associated with behavioral disorders. Here, we investigated glutamatergic functional connectivity by a postsynaptic density immediate-early gene-based network analysis. Pregnant female Sprague-Dawley rats were randomly divided into two experimental groups: one exposed to stress sessions and the other serving as a stress-free control group. Homer1 expression was evaluated by in situ hybridization technique in eighty-eight brain regions of interest of male rat offspring. Differences between the perinatal stress exposed group (PRS) (n = 5) and the control group (CTR) (n = 5) were assessed by performing the Student's t-test via SPSS 28.0.1.0 with Bonferroni correction. Additionally, all possible pairwise Spearman's correlations were computed as well as correlation matrices and networks for each experimental group were generated via RStudio and Cytoscape. Perinatal stress exposure was associated with Homer1a reduction in several cortical, thalamic, and striatal regions. Furthermore, it was found to affect functional connectivity between: the lateral septal nucleus, the central medial thalamic nucleus, the anterior part of the paraventricular thalamic nucleus, and both retrosplenial granular b cortex and hippocampal regions; the orbitofrontal cortex, amygdaloid nuclei, and hippocampal regions; and lastly, among regions involved in limbic system. Finally, the PRS networks showed a significant reduction in multiple connections for the ventrolateral part of the anteroventral thalamic nucleus after perinatal stress exposure, as well as a decrease in the centrality of ventral anterior thalamic and amygdaloid nuclei suggestive of putative reduced cortical control over these regions. Within the present preclinical setting, perinatal stress exposure is a modifier of glutamatergic early gene-based functional connectivity in neuronal circuits involved in behaviors relevant to model neurodevelopmental disorders.

A New Pandemic of the XXIst Century: The Growing Crisis of Adolescent Depression in the Digital Age

In a reality dominated by social media and affected by the recent COVID-19 pandemic, the mental health of people in various age groups has undoubtedly suffered, especially among young people. Statistics confirm that adolescent depression is a significant health problem and is the most common cause of disability in this age group. Research shows the multifactorial basis of this disease entity, placing particular emphasis on the genetic, environmental, and biological background. A family history of depression can increase the risk of developing depression by 4-fold. A teenager, being part of many systems, such as family, school community, and social media co-user, is exposed to many stressors. Maturing youth have a very demanding educational plan to implement, and depression causes a decline in cognitive functions, which are so important in acquiring knowledge. Among many patients, an additional risk is self-harm and suicide, which are part of the clinical picture of depressive disorders. Suicide accounts for about one-third of mortality among youth. We draw attention to the need to increase educational and psychoeducational impacts on adolescent depression, as it is a huge health problem that has an impact on all areas of a young person's life. The trend of depression among adolescents is constantly increasing. The aim of this article is to review the global causes and consequences of the growing number of cases of depression, self-harm, and suicide among children and adolescents, as well as contemporary approaches to management.

Epigenetic mechanisms linking early-life adversities and mental health

Early-life adversities, whether prenatal or postnatal exposure, have been linked to adverse mental health outcomes later in life increasing the risk of several psychiatric disorders. Research on its neurobiological consequences demonstrated an association between exposure to adversities and persistent alterations in the structure, function, and connectivity of the brain. Consistent evidence supports the idea that regulation of gene expression through epigenetic mechanisms are involved in embedding the impact of early-life experiences in the genome and mediate between social environments and later behavioral phenotypes. In addition, studies from rodent models and humans suggest that these experiences and the acquired risk factors can be transmitted through epigenetic mechanisms to offspring and the following generations potentially contributing to a cycle of disease or disease risk. However, one of the important aspects of epigenetic mechanisms, unlike genetic sequences that are fixed and unchangeable, is that although the epigenetic markings are long-lasting, they are nevertheless potentially reversible. In this review, we summarize our current understanding of the epigenetic mechanisms involved in the mental health consequences derived from early-life exposure to malnutrition, maltreatment and poverty, adversities with huge and pervasive impact on mental health. We also discuss the evidence about transgenerational epigenetic inheritance in mammals and experimental data suggesting that suitable social and pharmacological interventions could reverse adverse epigenetic modifications induced by early-life negative social experiences. In this regard, these studies must be accompanied by efforts to determine the causes that promote these adversities and that result in health inequity in the population.

Early life adversity in primates: Behavioral, endocrine, and neural effects

BACKGROUND

Evidence suggests that early life adversity is associated with maladaptive behaviors and is commonly an antecedent of stress-related psychopathology. This is particularly relevant to rearing in primate species as infant primates depend on prolonged, nurturant rearing by caregivers for normal development. To further understand the consequences of early life rearing adversity, and the relation among alterations in behavior, physiology and brain function, we assessed young monkeys that had experienced maternal separation followed by peer rearing with behavioral, endocrine and multimodal neuroimaging measures.

METHODS

50 young rhesus monkeys were studied, half of which were rejected by their mothers and peer reared, and the other half were reared by their mothers. Assessments were performed at approximately 1.8 years of age and included: threat related behavioral and cortisol responses, cerebrospinal fluid (CSF) measurements of oxytocin and corticotropin releasing hormone (CRH), and multimodal neuroimaging measures (anatomical scans, resting functional connectivity, diffusion tensor imaging, and threat-related regional glucose metabolism).

RESULTS

The results demonstrated alterations across behavioral, endocrine, and neuroimaging measures in young monkeys that were reared without their mothers. At a behavioral level in response to a potential threat, peer reared animals engaged in significantly less freezing behavior (p = 0.022) along with increased self-directed behaviors (p < 0.012). Levels of oxytocin in the CSF, but not plasma, were significantly reduced in the peer reared animals (p = 0.019). No differences in plasma cortisol or CSF CRH were observed. Diffusion tensor imaging revealed significantly decreased white matter density across the brain. Exploratory correlational and permutation analyses suggest that the impact of peer rearing on behavior, endocrine and brain structural alterations are mediated by separate parallel mechanisms.

CONCLUSIONS

Taken together, these results demonstrate in NHPs the importance of maternal rearing on the development of brain, behavior and hormonal systems that are linked to social functioning and adaptive responses. The findings suggest that the effects of maternal deprivation are mediated via multiple independent pathways which may account for the heterogeneity in behavioral and biological alterations observed in individuals that have experienced this early life adversity.

Gastrointestinal and brain barriers: unlocking gates of communication across the microbiota-gut-brain axis

Crosstalk between gut and brain has long been appreciated in health and disease, and the gut microbiota is a key player in communication between these two distant organs. Yet, the mechanisms through which the microbiota influences development and function of the gut-brain axis remain largely unknown. Barriers present in the gut and brain are specialized cellular interfaces that maintain strict homeostasis of different compartments across this axis. These barriers include the gut epithelial barrier, the blood-brain barrier and the blood-cerebrospinal fluid barrier. Barriers are ideally positioned to receive and communicate gut microbial signals constituting a gateway for gut-microbiota-brain communication. In this Review, we focus on how modulation of these barriers by the gut microbiota can constitute an important channel of communication across the gut-brain axis. Moreover, barrier malfunction upon alterations in gut microbial composition could form the basis of various conditions, including often comorbid neurological and gastrointestinal disorders. Thus, we should focus on unravelling the molecular and cellular basis of this communication and move from simplistic framing as 'leaky gut'. A mechanistic understanding of gut microbiota modulation of barriers, especially during critical windows of development, could be key to understanding the aetiology of gastrointestinal and neurological disorders.

The role of ncRNAs in depression

Depressive disorders have a significant impact on public health, and depression have an unsatisfactory recurrence rate and are challenging to treat. Non-coding RNAs (ncRNAs) are RNAs that do not code protein, which have been shown to be crucial for transcriptional regulation. NcRNAs are important to the onset, progress and treatment of depression because they regulate various physiological functions. This makes them distinctively useful as biomarkers for diagnosing and tracking responses to therapy among individuals with depression. It is important to seek out and summarize the research findings on the impact of ncRNAs on depression since significant advancements have been made in this area recently. Hence, we methodically outlined the findings of published researches on ncRNAs and depression, focusing on microRNAs. Above all, this review aims to improve our understanding of ncRNAs and provide new insights of the diagnosis and treatment of depression.

Lifestyle Factors Counteract the Neurodevelopmental Impact of Genetic Risk for Accelerated Brain Aging in Adolescence

BACKGROUND

The transition from childhood to adolescence is characterized by enhanced neural plasticity and a consequent susceptibility to both beneficial and adverse aspects of one's milieu.

METHODS

To understand the implications of the interplay between protective and risk-enhancing factors, we analyzed longitudinal data from the Adolescent Brain Cognitive Development (ABCD) Study (n = 834; 394 female). We probed the maturational correlates of positive lifestyle variables (friendships, parental warmth, school engagement, physical exercise, healthy nutrition) and genetic vulnerability to neuropsychiatric disorders (major depressive disorder, Alzheimer's disease, anxiety disorders, bipolar disorder, schizophrenia) and sought to further elucidate their implications for psychological well-being.

RESULTS

Genetic risk factors and lifestyle buffers showed divergent relationships with later attentional and interpersonal problems. These effects were mediated by distinguishable functional neurodevelopmental deviations spanning the limbic, default mode, visual, and control systems. More specifically, greater genetic vulnerability was associated with alterations in the normative maturation of areas rich in dopamine (D2), glutamate, and serotonin receptors and of areas with stronger expression of astrocytic and microglial genes, a molecular signature implicated in the brain disorders discussed here. Greater availability of lifestyle buffers predicted deviations in the normative functional development of higher density GABAergic (gamma-aminobutyric acidergic) receptor regions. The two profiles of neurodevelopmental alterations showed complementary roles in protection against psychopathology, which varied with environmental stress levels.

CONCLUSIONS

Our results underscore the importance of educational involvement and healthy nutrition in attenuating the neurodevelopmental sequelae of genetic risk factors. They also underscore the importance of characterizing early-life biomarkers associated with adult-onset pathologies.

Stress, epigenetics, and aging: Unraveling the intricate crosstalk

Aging, as a complex process involving multiple cellular and molecular pathways, is known to be exacerbated by various stresses. Because responses to these stresses, such as oxidative stress and genotoxic stress, are known to interplay with the epigenome and thereby contribute to the development of age-related diseases, investigations into how such epigenetic mechanisms alter gene expression and maintenance of cellular homeostasis is an active research area. In this review, we highlight recent studies investigating the intricate relationship between stress and aging, including its underlying epigenetic basis; describe different types of stresses that originate from both internal and external stimuli; and discuss potential interventions aimed at alleviating stress and restoring epigenetic patterns to combat aging or age-related diseases. Additionally, we address the challenges currently limiting advancement in this burgeoning field.

Vulnerability and resilience to prenatal stress exposure: behavioral and molecular characterization in adolescent rats

Exposure to stress can lead to long lasting behavioral and neurobiological consequences, which may enhance the susceptibility for the onset of mental disorders. However, there are significant individual differences in the outcome of stress exposure since only a percentage of exposed individuals may show pathological consequences, whereas others appear to be resilient. In this study, we aimed to characterize the effects of prenatal stress (PNS) exposure in rats at adolescence and to identify subgroup of animals with a differential response to the gestational manipulation. PNS adolescent offspring (regardless of sex) showed impaired emotionality in different pathological domains, such as anhedonia, anxiety, and sociability. However, using cluster analysis of the behavioral data we could identify 70% of PNS-exposed animals as vulnerable (PNS-vul), whereas the remaining 30% were considered resilient (PNS-res). At the molecular level, we found that PNS-res males show a reduced basal activation of the ventral hippocampus whereas other regions, such as amygdala and dorsal hippocampus, show significant PNS-induced changes regardless from vulnerability or resilience. Taken together, our results provide evidence of the variability in the behavioral and neurobiological effects of PNS-exposed offspring at adolescence. While these data may advance our understanding of the association between exposure to stress during gestation and the risk for psychopathology, the investigation of the mechanisms associated to stress vulnerability or resilience may be instrumental to develop novel strategies for therapeutic intervention.

Strong associations of telomere length and mitochondrial copy number with suicidality and abuse history in adolescent depressed individuals

Major depressive disorder (MDD) is highly prevalent in adolescents and is a major risk factor for suicidality. Recent evidence shows that accelerated cellular senescence/aging is associated with psychiatric illness, including depression, in adults. The present study examined if the relationships of telomere length (TL) and mitochondrial DNA copy number (mtDNAcn), two critical indicators of cellular senescence/aging, are altered in depressed adolescents and whether these alterations are associated with suicidality, early-life adversities, and other co-occuring factors. In genomic DNA isolated from 53 adolescents (ages 16-19, 19 MDD with suicide attempt/suicidal ideation [MDD + SI/SA], 14 MDD without SA/SI [MDD-SI/SA], and 20 healthy controls [HC]), TL and mtDNAcn were measured as the ratio between the number of telomere repeats and that of a single-copy nuclear-hemoglobin [HBG] gene or the amount of mtDNA (NADH dehydrogenase, subunit 1) relative to HBG. Our data show that TL was significantly lower, and mtDNAcn was significantly higher in the total MDD group than HC. TL was significantly lower and mtDNAcn was significantly higher in the MDD + SA/SI group than in the HC, whereas there were no differences in the MDD-SI/SA group. TL was positively correlated with mtDNAcn in both HC and MDD-SA/SI groups; however, TL was negatively correlated with mtDNAcn in MDD + SA/SI. Furthermore, TL was negatively correlated with the severity of both depression and anxiety, while mtDNAcn was positively correlated with the severity of prior emotional abuse. Our study indicates that cellular senescence is more advanced in depressed adolescents with suicidal ideation and that childhood emotional abuse may participate in such a process.

Early life stress impairs brain and mental development during childhood increasing the risk of developing psychiatric disorders

In recent years, it has become known that stress in childhood, called early life stress (ELS), affects the mental health of children, adolescents, and adults. Child maltreatment (CM) is an inappropriate form of childcare that interferes with children's normal brain and mind development. Previous studies have reported that CM severely affects brain development and function. For example, ELS causes brain vulnerability and increases the risk of developing psychiatric disorders. In addition, it is known that the different types and timing of abuse have different effects on the brain. Epidemiological and clinical studies are being conducted to understand the mechanism underlying abuse on a child's mental health and appropriate brain development; however, they are not fully understood. Therefore, studies using animal models, as well as humans, have been conducted to better understand the effects of CM. In this review, we discuss the effects of comparing previous findings on different types of CM in human and animal models. However, it should be noted that there are differences between animal models and humans such as genetic polymorphism and susceptibility to stress. Our review provides the latest insights into the negative effects of CM on children's development and on psychiatric disorders in adulthood.

Genome-Environment Interactions and Psychiatric Disorders

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

Animal models of PTSD: Comparison of the neuroendocrine and behavioral sequelae of immobilization and a modified single prolonged stress procedure that includes immobilization

A single exposure to some stressors results in long-lasting consequences reminiscent of those found in post-traumatic stress disorder (PTSD), but results are very often controversial. Although there is no consensus regarding the best animal models of PTSD, the single prolonged stress (SPS) model, consisting of sequential exposure within the same day to various stressors (typically restraint, forced swim, and ether), has gained acceptance. However, results, particularly those related to the hypothalamic-pituitary-adrenal (HPA) axis, are inconsistent and there is no evidence that SPS is clearly distinct from models using a single severe stressor. In the present study, we compared in male rats the behavioral and neuroendocrine (HPA) consequences of exposure to immobilization on boards (IMO) with a SPS-like model (SPSi) in which IMO and isoflurane were substituted for restraint and ether, respectively. Both procedures caused a similar impact on food intake and body weight as well as on sensitization of the HPA response to a novel environment (hole-board) on the following day. Reduction of activity/exploration in the hole-board was also similar with both stressors, although the impact of sudden noise was higher in SPSi than IMO. Neither IMO nor SPSi significantly affected contextual fear conditioning acquisition, although a similar trend for impaired fear extinction was observed compared to controls. Exposure to additional stressors in the SPSi did not interfere with homotypic adaptation of the HPA axis to IMO. Thus, only modest neuroendocrine and behavioral differences were observed between IMO and SPSi and more studies comparing putative PTSD models are needed.

Novel pathogenesis of post-traumatic stress disorder studied in transgenic mice

Posttraumatic stress disorder (PTSD) is very common after exposure to trauma, mental stress or violence. Because objective biological markers for PTSD are lacking, exactly diagnosing PTSD is a challenge for clinical psychologists. In-depth research on the pathogenesis of PTSD is a key for solving this problem. In this work, we used male Thy1-YFP transgenic mice, in which neurons are fluorescently labeled, to research the effects of PTSD on neurons in vivo. We initially discovered that pathological stress associated with PTSD increased the activation of glycogen synthesis kinase-beta (GSK-3β) in neurons and induced the translocation of the transcription factor forkhead box-class O3a (FoxO3a) from the cytoplasm to the nucleus, which decreased the expression of uncoupling protein 2 (UCP2) and increased mitochondrial production of reactive oxygen species (ROS) to trigger neuronal apoptosis in the prefrontal cortex (PFC). Furthermore, the PTSD model mice showed increased freezing and anxiety-like behaviors and more severe decrease of memory and exploratory behavior. Additionally, leptin attenuated neuronal apoptosis by increasing the phosphorylation of signal transducer and activator of transcription 3 (STAT3), which further elevated the expression of UCP2 and inhibited the mitochondrial production of ROS induced by PTSD, thus reducing neuronal apoptosis and ameliorating PTSD-related behaviors. Our study is expected to promote the exploration of PTSD-related pathogenesis in neural cells and the clinical effectiveness of leptin for PTSD.

Potential of Circulating miRNAs as Molecular Markers in Mood Disorders and Associated Suicidal Behavior

Mood disorders are the most prevalent psychiatric disorders associated with significant disability, morbidity, and mortality. The risk of suicide is associated with severe or mixed depressive episodes in patients with mood disorders. However, the risk of suicide increases with the severity of depressive episodes and is often presented with higher incidences in bipolar disorder (BD) patients than in patients with major depression (MDD). Biomarker study in neuropsychiatric disorders is critical for developing better treatment plans by facilitating more accurate diagnosis. At the same time, biomarker discovery also provides more objectivity to develop state-of-the-art personalized medicine with increased accuracy through clinical interventions. Recently, colinear changes in miRNA expression between brain and systemic circulation have added great interest in examining their potential as molecular markers in mental disorders, including MDD, BD, and suicidality. A present understanding of circulating miRNAs in body fluids implicates their role in managing neuropsychiatric conditions. Most notably, their use as prognostic and diagnostic markers and their potential role in treatment response have significantly advanced our knowledge base. The present review discusses circulatory miRNAs and their underlying possibilities to be used as a screening tool for assessing major psychiatric conditions, including MDD, BD, and suicidal behavior.