Epigenetic Risk Factors in PTSD and Depression

Paeoniflorin exerts anti-PTSD effects in adult rats by modulating hippocampus and amygdala histone acetylation modifications in response to early life stress

Early life stress (ELS) can cause long-term changes by epigenetic factors, especially histone acetylation modification, playing a crucial role, affect normal cognition, mood, and behavior, and increase susceptibility to post-traumatic stress disorder (PTSD) in adulthood. It has been found that paeoniflorin (PF) can cross the blood-brain barrier to exert anti-PTSD effects on adult PTSD rats. However, whether PF can alleviate the harmful effects caused by ELS in adulthood has not yet been reported. Therefore, to explore the relationship between ELS and PTSD susceptibility in adulthood and its mechanism, in this study, SPS was used as a stressor of ELS, and the mathematical tool Z-normalization was employed as an evaluation criterion of behavioral resilience susceptibility. To investigate the regulatory mechanism of PF on histone acetylation in the hippocampus and amygdala of ELS rats in adulthood, using changes in HATs/HDACs as the entry point, meanwhile, the epigenetic marks (H3K9 and H4K12) in the key brain regions of ELS (hippocampus and amygdala) were evaluated, and the effects of PF on behavioral representation and PTSD susceptibility were observed. This study found that ELS lead to a series of PTSD-like behaviors in adulthood and caused imbalance of HATs/HDACs ratio in the hippocampus and amygdala, which confirms that ELS is an important risk factor for the development of PTSD in adulthood. In addition, paeoniflorin may improve ELS-induced PTSD-like behaviors and reduce the susceptibility of ELS rats to develop PTSD in adulthood by modulating the HATs/HDACs ratio in the hippocampus and amygdala.

Limited Cheese Intake Paradigm Replaces Patterns of Behavioral Disorders in Experimental PTSD: Focus on Resveratrol Supplementation

Currently, the efficacy of drug therapy for post-traumatic stress disorder or PTSD leaves much to be desired, making nutraceutical support a promising avenue for treatment. Recent research has identified the protective effects of resveratrol in PTSD. Here, we tested the behavioral and neurobiological effects of combining cheese consumption with resveratrol supplements in an experimental PTSD model. Using the elevated plus maze test, we observed that cheese intake resulted in a shift from anxiety-like behavior to depressive behavior, evident in increased freezing acts. However, no significant changes in the anxiety index value were observed. Interestingly, supplementation with cheese and resveratrol only led to the elimination of freezing behavior in half of the PTSD rats. We further segregated the rats into two groups based on freezing behavior: Freezing+ and Freezing0 phenotypes. Resveratrol ameliorated the abnormalities in Monoamine Oxidize -A and Brain-Derived Neurotrophic Factor gene expression in the hippocampus, but only in the Freezing0 rats. Moreover, a negative correlation was found between the number of freezing acts and the levels of Monoamine Oxidize-A and Brain-Derived Neurotrophic Factor mRNAs in the hippocampus. The study results show promise for resveratrol supplementation in PTSD treatment. Further research is warranted to better understand the underlying mechanisms and optimize the potential benefits of resveratrol supplementation for PTSD.

Early Life Stress (ELS) Effects on Fetal and Adult Bone Development

Early life stress (ELS) refers to harmful environmental events (i.e., poor maternal health, metabolic restraint, childhood trauma) occurring during the prenatal and/or postnatal period, which may cause the 'epigenetic corruption' of cellular and molecular signaling of mental and physical development. While the impact of ELS in a wide range of human diseases has been confirmed, the ELS susceptibility to bone diseases has been poorly explored. In this review, to understand the potential mediating pathways of ELS in bone diseases, PRISMA criteria were used to analyze different stress protocols in mammal models and the effects elicited in dams and their progeny. Data collected, despite the methodological heterogeneity, show that ELS interferes with fetal bone formation, also revealing that the stress type and affected developmental phase may influence the variety and severity of bone anomalies. Interestingly, these findings highlight the maternal and fetal ability to buffer stress, establishing a new role for the placenta in minimizing ELS perturbations. The functional link between ELS and bone impairments will boost future investigations on maternal stress transmission to the fetus and, parallelly, help the assessment of catch-up mechanisms of skeleton adaptations from the cascading ELS effects.

Sex-specific roles of hippocampal microRNAs in stress vulnerability and resilience

Contrary to intuition, most individuals are resilient to psychological trauma and only a minority is vulnerable. Men and women are known to respond differently to trauma exposure, however, mechanisms underlying the relationship between sex differences and trauma resilience and vulnerability are not yet fully understood. Taking advantage of the Behavioral Profiling approach, which enables differentiating between 'affected' and 'unaffected' individuals, we examined sex-associated differences in stress exposure effects on hippocampal expression of selected stress-related GABA-A receptor targeting miRNAs. Levels of the miRNA-144 and miRNA-33 were measured in male and female affected (vulnerable, e.g., higher freezing time) and unaffected (resilient) rats. In male rats, increased levels of miRNA-144 and miRNA-33 were observed in the dorsal dentate gyrus (dDG) and ventral dentate gyrus (vDG) respectively, of stress-exposed but unaffected animals. In females, we observed an increased expression of miRNA-144 and miRNA-33 in the ventral cornu ammonis 1 (vCA1) of affected animals. Accordingly, we inhibited miRNAs expression selectively in hippocampal subregions using oligonucleotides containing locked nucleic acid bases, to examine the miRNAs' causal contribution to either vulnerability or resilience to stress in each sex. Inhibition of miRNA-144 in dDG and miRNA-33 in vDG in males resulted in an increased prevalence of vulnerable animals, while inhibition of miRNA-144 and miRNA-33 in vCA1 in females increased the proportion of resilient animals. The current findings reveal a critical sex-associated difference in the role of miRNAs in stress vulnerability and resilience. This novel understanding of sex-associated epigenetic involvement in the mechanism of stress-related psychopathologies may help improve gender-specific diagnosis and effective treatment.

Environmental enrichment mitigates PTSD-like behaviors in adult male rats exposed to early life stress by regulating histone acetylation in the hippocampus and amygdala

Early life stress (ELS) can cause long-term changes in gene expression, affect cognition, mood, and behavior, and increase susceptibility to post-traumatic stress disorder (PTSD) in adulthood, in which the histone acetylation plays a crucial role. Studies have found that environmental enrichment (EE) mitigated the unfavorable outcomes of ELS. However, the underlying mechanism of the histone acetylation is not yet completely clear. The purpose of this study was to explore the effect of EE on the histone acetylation after ELS. In this study, using single prolonged stress (SPS) paradigm in early adolescent rats explored the long-term effects of ELS on behavior, the activity of histone acetyltransferases (HATs) and histone deacetylases (HDACs), as well as the acetylation levels of the lysine 9 site of histone H3 (H3K9) and lysine 12 site of histone H4 (H4K12) in the hippocampus and amygdala. Meanwhile, the protective effects of EE intervention were examined. We found that adult male rats exposed to ELS showed behavioral changes, including reduced locomotor activity, increased anxiety-like behaviors, impaired spatial learning and memory, enhanced contextual and cued fear memory, and the HATs/HDACs ratio and acetyl H3K9 (Ac-H3K9) and acetyl H4K12 (Ac-H4K12) were increased in the hippocampus and decreased in the amygdala. Furthermore, EE attenuated the behavioral abnormalities from ELS, possibly through down-regulating the activity of HATs in the hippocampus and up-regulating HDACs activities in the amygdala. These finding suggested that EE could ameliorate ELS-induced PTSD-like behaviors by regulating histone acetylation in the hippocampus and amygdala, reducing the susceptibility to PTSD in adulthood.

Epigenetic and Neuronal Activity Markers Suggest the Recruitment of the Prefrontal Cortex and Hippocampus in the Three-Hit Model of Depression in Male PACAP Heterozygous Mice

Depression and its increasing prevalence challenge patients, the healthcare system, and the economy. We recently created a mouse model based on the three-hit concept of depression. As genetic predisposition (first hit), we applied pituitary adenylate cyclase-activating polypeptide heterozygous mice on CD1 background. Maternal deprivation modeled the epigenetic factor (second hit), and the chronic variable mild stress was the environmental factor (third hit). Fluoxetine treatment was applied to test the predictive validity of our model. We aimed to examine the dynamics of the epigenetic marker acetyl-lysine 9 H3 histone (H3K9ac) and the neuronal activity marker FOSB in the prefrontal cortex (PFC) and hippocampus. Fluoxetine decreased H3K9ac in PFC in non-deprived animals, but a history of maternal deprivation abolished the effect of stress and SSRI treatment on H3K9ac immunoreactivity. In the hippocampus, stress decreased, while SSRI increased H3K9ac immunosignal, unlike in the deprived mice, where the opposite effect was detected. FOSB in stress was stimulated by fluoxetine in the PFC, while it was inhibited in the hippocampus. The FOSB immunoreactivity was almost completely abolished in the hippocampus of the deprived mice. This study showed that FOSB and H3K9ac were modulated in a territory-specific manner by early life adversities and later life stress interacting with the effect of fluoxetine therapy supporting the reliability of our model.

A History of Childhood Maltreatment Has Substance- and Sex-Specific Effects on Craving During Treatment for Substance Use Disorders

RATIONALE

Childhood maltreatment (CM) leads to detrimental mental health outcomes, such as substance use disorders (SUD). This study examined prevalence and severity of all five types of CM with respect to specific substances and sex in treatment-seeking individuals with SUD. The influences of type of CM and symptoms of depressiveness, anxiety, and perceived stress on substance craving at admission as well as craving reduction during SUD treatment were examined.

METHODS

N = 546 patients in treatment for SUD and N = 109 individuals in opioid maintenance treatment filled out questionnaires regarding CM (Childhood Trauma Questionnaire) and psychopathologies. Substance craving was assessed throughout treatment using the Mannheim Craving Scale. Group differences in CM, type of substance and sex were examined. General linear models were applied to examine influences on substance craving.

RESULTS

Higher prevalence and severity of all five subtypes of CM were observed in individuals with SUD compared to the general population. Women were more severely affected by emotional and sexual abuse than men. Patients with cannabis use disorder reported more severe experiences of emotional abuse compared to all other substances. Craving at admission to treatment was influenced by emotional abuse, however, symptoms of depressiveness, anxiety, and perceived stress contributed to craving at admission or craving reduction during treatment.

CONCLUSION

CM relates to SUD and should be incorporated in prevention and treatment of SUD. Underlying mechanisms of the association might relate to impairments in processing and regulation of stress, emotions, and interpersonal relations following a history of CM.

Fluoxetine treatment supports predictive validity of the three hit model of depression in male PACAP heterozygous mice and underpins the impact of early life adversity on therapeutic efficacy

According to the three hit concept of depression, interaction of genetic predisposition altered epigenetic programming and environmental stress factors contribute to the disease. Earlier we demonstrated the construct and face validity of our three hit concept-based mouse model. In the present work, we aimed to examine the predictive validity of our model, the third willnerian criterion. Fluoxetine treatment was applied in chronic variable mild stress (CVMS)-exposed (environmental hit) CD1 mice carrying one mutated allele of pituitary adenylate cyclase-activating polypeptide gene (genetic hit) that were previously exposed to maternal deprivation (epigenetic hit) vs. controls. Fluoxetine reduced the anxiety level in CVMS-exposed mice in marble burying test, and decreased the depression level in tail suspension test if mice were not deprived maternally. History of maternal deprivation caused fundamental functional-morphological changes in response to CVMS and fluoxetine treatment in the corticotropin-releasing hormone-producing cells of the bed nucleus of the stria terminalis and central amygdala, in tyrosine-hydroxylase content of ventral tegmental area, in urocortin 1-expressing cells of the centrally projecting Edinger-Westphal nucleus, and serotonergic cells of the dorsal raphe nucleus. The epigenetic background of alterations was approved by altered acetylation of histone H3. Our findings further support the validity of both the three hit concept and that of our animal model. Reversal of behavioral and functional-morphological anomalies by fluoxetine treatment supports the predictive validity of the model. This study highlights that early life stress does not only interact with the genetic and environmental factors, but has strong influence also on therapeutic efficacy.

Heterogeneous Mediation Analysis on Epigenomic PTSD and Traumatic Stress in a Predominantly African American Cohort

DNA methylation (DNAm) has been suggested to play a critical role in post-traumatic stress disorder (PTSD), through mediating the relationship between trauma and PTSD. However, this underlying mechanism of PTSD for African Americans still remains unknown. To fill this gap, in this article, we investigate how DNAm mediates the effects of traumatic experiences on PTSD symptoms in the Detroit Neighborhood Health Study (DNHS) (2008-2013) which involves primarily African Americans adults. To achieve this, we develop a new mediation analysis approach for high-dimensional potential DNAm mediators. A key novelty of our method is that we consider heterogeneity in mediation effects across subpopulations. Specifically, mediators in different subpopulations could have opposite effects on the outcome, and thus could be difficult to identify under a traditional homogeneous model framework. In contrast, the proposed method can estimate heterogeneous mediation effects and identifies subpopulations in which individuals share similar effects. Simulation studies demonstrate that the proposed method outperforms existing methods for both homogeneous and heterogeneous data. We also present our mediation analysis results of a dataset with 125 participants and more than 450,000 CpG sites from the DNHS study. The proposed method finds three subgroups of subjects and identifies DNAm mediators corresponding to genes such as HSP90AA1 and NFATC1 which have been linked to PTSD symptoms in literature. Our finding could be useful in future finer-grained investigation of PTSD mechanism and in the development of new treatments for PTSD.

Depression in post-traumatic stress disorder

Major depressive disorder (MDD) symptoms commonly occur after trauma-exposure, both alone and in combination with post-traumatic stress disorder (PTSD). This article reviews recent research on comorbidity between these disorders, including its implications for symptom severity and response to treatment. Despite considerable symptom overlap, the two disorders represent distinct constructs and depend, at least in part, on separate biological mechanisms. Both, however, are also clearly related to stress psychopathology. We recommend that more research focus specifically on the study of individual differences in symptom expression in order to identify distinct subgroups of individuals and develop targeted treatments. However, a barrier to this line of inquiry is the trend of excluding particular patients from clinical trials of new interventions based on symptom severity or comorbidity. Another obstacle is the overreliance on self-report measures in human research. We argue that developing computer-based behavioral measures in order to supplement self-report can help address this challenge. Furthermore, we propose that these measures can help tie findings from human and non-human animal research. A number of paradigms have been used to model MDD-and PTSD-like behavior in animals. These models remain valuable for understanding the biological basis of these disorders in humans and for identifying potential interventions, but they have been underused for the study of comorbidity. Although the interpretation of animal behavior remains a concern, we propose that this can also be overcome through the development of close human analogs to animal paradigms.

Epigenetics: A missing link between early life stress and depression

Research has suggested a relationship between early life stress, and depression in particular longer episodes of depression with treatment resistant outcomes. However, the underlying mechanisms for this association remain poorly understood. Molecular studies indicate that, in general, the hereditary character of psychiatric disorders are polygenic, multifactorial and highly complex, with innumerable low-effect genetic variants interacting with each other. In addition, the importance of the environment and its interaction with genes has pointed to a fundamental role of epigenetic mechanisms in psychiatric disorders, such as methylation of deoxyribonucleic acid (DNA), alterations, histone actions and regulation of gene expression by non-coding ribonucleic acids (RNAs). This article provides an overview of the interplay of epigenetics, the HPA axis, early life stress and the development of depression. Advances in our knowledge of epigenetics in the context of early life stress and depression provide a new understanding of the genetic influence on psychopathology and could lead to the identification of new targets for clinical intervention.

Losing DNA methylation at repetitive elements and breaking bad

Background

DNA methylation is an epigenetic chromatin mark that allows heterochromatin formation and gene silencing. It has a fundamental role in preserving genome stability (including chromosome stability) by controlling both gene expression and chromatin structure. Therefore, the onset of an incorrect pattern of DNA methylation is potentially dangerous for the cells. This is particularly important with respect to repetitive elements, which constitute the third of the human genome.

Main body

Repetitive sequences are involved in several cell processes, however, due to their intrinsic nature, they can be a source of genome instability. Thus, most repetitive elements are usually methylated to maintain a heterochromatic, repressed state. Notably, there is increasing evidence showing that repetitive elements (satellites, long interspersed nuclear elements (LINEs), Alus) are frequently hypomethylated in various of human pathologies, from cancer to psychiatric disorders. Repetitive sequences’ hypomethylation correlates with chromatin relaxation and unscheduled transcription. If these alterations are directly involved in human diseases aetiology and how, is still under investigation.

Conclusions

Hypomethylation of different families of repetitive sequences is recurrent in many different human diseases, suggesting that the methylation status of these elements can be involved in preservation of human health. This provides a promising point of view towards the research of therapeutic strategies focused on specifically tuning DNA methylation of DNA repeats.

Adverse Childhood Experiences in Trainees and Physicians With Professionalism Lapses: Implications for Medical Education and Remediation

PURPOSE

Unprofessional behavior, which can include failure to engage, dishonest and/or disrespectful behavior, and poor self-awareness, can be demonstrated by medical trainees and practicing physicians. In the authors' experience, these types of behaviors are associated with exposure to adverse childhood experiences (ACEs). Given this overlap, the authors studied the percentage of ACEs among trainees and physicians referred for fitness-for-duty evaluations and patterns between the types of ACEs experienced and the reason for referral.

METHOD

A final sample of 123 cases of U.S. trainees and physicians who had been referred to a Midwestern center for assessment and/or remediation of professionalism issues from 2013 to 2018 was created. Included professionalism lapses fell within 3 categories: boundary violation, disruptive behavior, or potential substance use disorder concerns. All participants completed a psychosocial developmental interview, which includes questions about ACE exposure. Overall rate of reported ACEs and types of ACEs reported were explored.

RESULTS

Eighty-six (70%) participants reported at least 1 ACE, while 27 (22%) reported 4 or more. Compared with national data, these results show significantly higher occurrence rates of 1 or more ACEs and a lower occurrence rate of 0 ACEs. ACEs that predicted reasons for referral were physical or sexual abuse, feeling unwanted or unloved, witnessing abuse of their mother or stepmother, or caretaker substance use.

CONCLUSIONS

In this sample, ACE exposure was associated with professionalism issues. Remediating individuals with professionalism issues and exposure to ACEs can be complicated by heightened responses to stressful stimuli, difficulties with collaboration and trust, and decreased self-efficacy. Adoption of a trauma-informed medical education approach may help those that have been impacted by trauma rebuild a sense of control and empowerment. The findings of this study may be useful predictors in identifying those at risk of problematic behavior and recidivism before a sentinel event.

Child maltreatment, cognitive functions and the mediating role of mental health problems among maltreated children and adolescents in Uganda

BACKGROUND

Child maltreatment poses high risks to the mental health and cognitive functioning of children not only in childhood but also in later life. However, it remains unclear whether child maltreatment is directly associated with impaired cognitive functioning or whether this link is mediated by mental health problems. Our study aimed at examining this research question among children and adolescents in Uganda.

METHODS

A sample of 232 school-going children and adolescents with a mean age of 14.03 (SD = 3.25) was assessed on multiple forms of maltreatment using the Maltreatment and Abuse Chronology Exposure-Pediatric Version (pediMACE). Executive functions were assessed by the Tower of London task and working memory by the Corsi Block Tapping task, while mental health problems were assessed using the Child PTSD Symptom Scale for PTSD and the Center for Epidemiological Studies Depression Scale for Children (CES-DC).

RESULTS

In total, 232 (100%) of the participant reported to have experienced at least one type of maltreatment in their lifetime including emotional, physical, and sexual violence as well as neglect. We found a negative association between child maltreatment and executive functions (β = - 0.487, p < 0.001) and working memory (β = - 0.242, p = 0.001). Mental health problems did not mediate this relationship.

CONCLUSIONS

Child maltreatment seems to be related to lower working memory and executive functioning of affected children and adolescents even after controlling for potential cofounders. Our study indicates that child maltreatment the affects children's cognitive functionality beyond health and well-being.

Environmental enrichment modulates HPA axis reprogramming in adult male rats exposed to early adolescent stress

Exposure to early stressful events increases susceptibility to post-traumatic stress disorder (PTSD) in adulthood, in which the hypothalamic-pituitary-adrenal (HPA) axis plays a crucial role. Studies have found that environmental enrichment (EE) mitigates the detrimental outcomes of early adversity. However, the HPA-related mechanism remains unclear. In this study, we used the single prolonged stress (SPS) paradigm to explore the long-term effects of early adolescent stress on behavior, HPA axis activity, as well as expression levels of the glucocorticoid receptor (GR), mineralocorticoid receptor (MR), corticotropin-releasing hormone receptor 1 (CRF1R) and CRF2R in the hypothalamus and hippocampus. Meanwhile, the protective effects of EE intervention were examined. We found that adult male rats exposed to adolescent stress showed reduced locomotor activity, increased anxiety-like behaviors, enhanced contextual fear memory, elevated basal plasma ACTH levels, and enhanced HPA negative feedback inhibition, as indicated by decreased plasma ACTH levels in the dexamethasone suppression test (DST). Furthermore, EE normalized the behavioral abnormalities and enhanced HPA negative feedback in stressed rats, possibly through down-regulating GR expression in the hippocampus and hypothalamus. These findings suggested that EE could ameliorate adolescent stress-induced PTSD-like behaviors and aberrant reprogramming of the HPA axis, reducing the risk of developing PTSD in adulthood.

Maternal Separation-Induced Histone Acetylation Correlates with BDNF-Programmed Synaptic Changes in an Animal Model of PTSD with Sex Differences

Maternal separation (MS) causes long-lasting epigenetic changes in the brain and increases vulnerability to traumatic events in adulthood. Of interest, there may be sex-specific differences in these epigenetic changes. In this study, the extent of histone acetylation in the hippocampus (HIP) and the expression of BDNF were measured to determine whether BDNF influences risk of PTSD following MS in early life. Rat offspring were separated from their dams (3 h/day or 6 h/day from PND2~PND14). Then, pups were treated with a single prolonged stress (SPS) procedure when they reached adulthood (PND80). In animals stressed with the SPS procedure in adulthood, those that had increased MS intensity in childhood demonstrated more significant changes in performance on tests of anxiety, depression, and contextual fear memory. Reduced levels of total BDNF mRNA and protein were observed after SPS treatment and further declined in groups with greater MS time in childhood. Interestingly, these changes were correlated with decreased H3K9ac levels and increased HDAC2 levels. Additional MS also led to more severe ultrastructural synaptic damage in rats that experienced the SPS procedure, particularly in the CA1 and CA3 region of the HIP, reflecting impaired synaptic plasticity in these regions. Interestingly, male rats in the MS3h-PTSD group showed decreased anxiety, but no similar changes were found in female rats, suggesting a degree of gender specificity in coping with stress after mild MS. In summary, this study suggests that the epigenetic signatures of the BDNF genes can be linked to HIP responses to stress, providing insights that may be relevant for people at risk of stress-related psychopathologies.

Oligodendrocytes as A New Therapeutic Target in Schizophrenia: From Histopathological Findings to Neuron-Oligodendrocyte Interaction

Imaging and postmortem studies have revealed disturbed oligodendroglia-related processes in patients with schizophrenia and provided much evidence for disturbed myelination, irregular gene expression, and altered numbers of oligodendrocytes in the brains of schizophrenia patients. Oligodendrocyte deficits in schizophrenia might be a result of failed maturation and disturbed regeneration and may underlie the cognitive deficits of the disease, which are strongly associated with impaired long-term outcome. Cognition depends on the coordinated activity of neurons and interneurons and intact connectivity. Oligodendrocyte precursors form a synaptic network with parvalbuminergic interneurons, and disturbed crosstalk between these cells may be a cellular basis of pathology in schizophrenia. However, very little is known about the exact axon-glial cellular and molecular processes that may be disturbed in schizophrenia. Until now, investigations were restricted to peripheral tissues, such as blood, correlative imaging studies, genetics, and molecular and histological analyses of postmortem brain samples. The advent of human-induced pluripotent stem cells (hiPSCs) will enable functional analysis in patient-derived living cells and holds great potential for understanding the molecular mechanisms of disturbed oligodendroglial function in schizophrenia. Targeting such mechanisms may contribute to new treatment strategies for previously treatment-resistant cognitive symptoms.

Differential activation of the renin-angiotensin-aldosterone-system in response to childhood and adulthood trauma

OBJECTIVE

Previous evidence suggested lasting and cumulative effects of traumatization on the renin-angiotensin-aldosterone-system (RAAS). However, it is unclear whether traumas during childhood and those experienced in adulthood differentially impact the RAAS. In this study, we sought to investigate main and putative interactive effects of childhood and adulthood trauma on RAAS functioning.

METHODS

Plasma concentrations of renin and aldosterone were measured in a general population sample (n = 2016). Childhood trauma was assessed using the Childhood Trauma Questionnaire (CTQ), adulthood trauma was measured using the PTSD module of the Structured Clinical Interview of the DSM-IV. Linear regression models were calculated to assess the relations between childhood or adulthood traumatization with renin and aldosterone concentrations.

RESULTS

Exposure to (ß = 0.094; p = 0.01), severity of childhood trauma (ß = 0.004; p = 0.01) were associated with increased aldosterone, but not renin levels. Results were carried by all dimensions of abuse, while childhood neglect was not associated with altered RAAS activity. In contrast, adulthood traumas (ß = 0.113; p < 0.01) were significantly associated with increased renin concentrations. Subjects with PTSD (renin: ß = 0.345; p = 0.01; aldosterone: ß = 0.232; p = 0.04) and those who had been exposed to both childhood and adulthood trauma showed increases in renin (ß = 0.180; p < 0.01) and aldosterone (ß = 0.340; p < 0.01) levels.

DISCUSSION

These findings indicate that trauma is associated with differential alterations of the RAAS depending on the time of traumatization. Moreover, exposure to childhood or adulthood trauma may act synergistically on the RAAS, resulting in severe dysregulation of the RAAS. The results contribute to explain associations between trauma and enhanced risk for physical disease.

MicroRNAs in Post-traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is a psychiatric disorder that can develop following exposure to or witnessing of a (potentially) threatening event. A critical issue is to pinpoint the (neuro)biological mechanisms underlying the susceptibility to stress-related disorder such as PTSD, which develops in the minority of ~15% of individuals exposed to trauma. Over the last few years, a first wave of epigenetic studies has been performed in an attempt to identify the molecular underpinnings of the long-lasting behavioral and mental effects of trauma exposure. The potential roles of non-coding RNAs (ncRNAs) such as microRNAs (miRNAs) in moderating or mediating the impact of severe stress and trauma are increasingly gaining attention. To date, most studies focusing on the roles of miRNAs in PTSD have, however, been completed in animals, using cross-sectional study designs and focusing almost exclusively on subjects with susceptible phenotypes. Therefore, there is a strong need for new research comprising translational and cross-species approaches that use longitudinal designs for studying trajectories of change contrasting susceptible and resilient subjects. The present review offers a comprehensive overview of available studies of miRNAs in PTSD and discusses the current challenges, pitfalls, and future perspectives of this field.

Current and future functional imaging techniques for post-traumatic stress disorder

Posttraumatic stress disorder (PTSD) is a trauma and stressor related psychiatric disorder associated with structural, metabolic, and molecular alternations in several brain regions including diverse cortical areas, neuroendocrine regions, the striatum, dopaminergic, adrenergic and serotonergic pathways, and the limbic system. We are in critical need of novel therapeutics and biomarkers for PTSD and a deep understanding of cutting edge imaging and spectroscopy methods is necessary for the development of promising new approaches to better diagnose and treat the disorder. According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) criterion, all forms of traumatic stress-induced disorder are considered acute stress disorder for the first month following the stressor. Only after symptoms do not remit for one month can the disorder be deemed PTSD. It would be particularly useful to differentiate between acute stress disorder and PTSD during the one month waiting period so that more intensive treatments can be applied early on to patients with a high likelihood of developing PTSD. This would potentially enhance treatment outcomes and/or prevent the development of PTSD. Comprehension of the qualities and limitations of currently applied methods as well as the novel emerging techniques provide invaluable knowledge for fast paced development. Conventional methods of studying PTSD have proven to be insufficient for diagnosis, measurement of treatment efficacy, and monitoring disease progression. As the field currently stands, there is no diagnostic biomarker available for any psychiatric disease, PTSD included. Currently, emerging and available technologies are not utilized to their full capacity and in appropriate experimental designs for the most fruitful possible studies in this area. Therefore, there is an apparent need for improved methods in PTSD research. This review demonstrates the current state of the literature in PTSD, including molecular, cellular, and behavioral indicators, possible biomarkers and clinical and pre-clinical imaging techniques relevant to PTSD, and through this, elucidate the void of current practical imaging and spectroscopy methods that provide true biomarkers for the disorder and the significance of devising new techniques for future investigations. We are unlikely to develop a single biomarker for any psychiatric disorder however. As psychiatric disorders are incomparably complex compared to other medical diagnoses, its most likely that transcriptomic, metabolomic and structural and connectomic imaging data will have to be analyzed in concert in order to produce a dependable non-behavioral marker of PTSD. This can explain the necessity of bridging conventional approaches to novel technologies in order to create a framework for further discoveries in the treatment of PTSD.

Conventional methods of studying posttraumatic stress disorder (PTSD) have proven to be insufficient for diagnosis. We have reviewed clinical and preclinical imaging techniques as well as molecular, cellular, and behavioral indicators for PTSD.

Studying and modulating schizophrenia-associated dysfunctions of oligodendrocytes with patient-specific cell systems

Postmortem studies in patients with schizophrenia (SCZ) have revealed deficits in myelination, abnormalities in myelin gene expression and altered numbers of oligodendrocytes in the brain. However, gaining mechanistic insight into oligodendrocyte (OL) dysfunction and its contribution to SCZ has been challenging because of technical hurdles. The advent of individual patient-derived human-induced pluripotent stem cells (hiPSCs), combined with the generation of in principle any neuronal and glial cell type, including OLs and oligodendrocyte precursor cells (OPCs), holds great potential for understanding the molecular basis of the aetiopathogenesis of genetically complex psychiatric diseases such as SCZ and could pave the way towards personalized medicine. The development of neuronal and glial co-culture systems now appears to enable the in vitro study of SCZ-relevant neurobiological endophenotypes, including OL dysfunction and myelination, with unprecedented construct validity. Nonetheless, the meaningful stratification of patients before the subsequent functional analyses of patient-derived cell systems still represents an important bottleneck. Here, to improve the predictive power of ex vivo disease modelling we propose using hiPSC technology to focus on representatives of patient subgroups stratified for genomic and/or phenomic features and neurobiological cell systems. Therefore, this review will outline the evidence for the involvement of OPCs/OLs in SCZ in the context of their proposed functions, including myelination and axon support, the implications for hiPSC-based cellular disease modelling and potential strategies for patient selection.

Rosmarinic acid reverses the deleterious effects of repetitive stress and tat protein

Human immunodeficiency virus type 1 (HIV) has infected more than 40 million people worldwide and is associated with central nervous system (CNS) disruption in at least 30% of these persons. The use of highly active antiretroviral therapy (HAART) has significantly reduced the systemic immunopathology associated with HIV, but the occurrence of neurological disorders continues to be reported in notable numbers. The present study evaluated the potential of rosmarinic acid to reverse the detrimental effects of an intracerebral injection of the viral protein tat. Control and tat-injected rats were also subjected to repetitive restrain stress (RRS) for 28 days, 6 h per day, to investigate whether subsequent stress exposure would worsen the effects of tat. 14 days after the initiation of RRS, animals were treated with rosmarinic acid (10 mg/kg given intraperitoneally) daily until the end of the stress exposure period. We assessed locomotor activity and anxiety-like behavioral changes. We also measured plasma corticosterone levels and quantified the expression of mineralocorticoid receptors (MR), glucocorticoid receptors (GR) and brain-derived neurotrophic factor (BDNF) in the hippocampus. Rosmarinic acid attenuated anxiety-like behavior induced by tat and stress, reduced plasma corticosterone levels and increased the expression of hippocampal GR, MR and BDNF when compared to controls. These results suggest that rosmarinic acid may reverse the anxiogenic effect of HIV-1 viral protein tat and related stress through modulation of the hypothalamic-pituitary-adrenal axis and hippocampal neurotrophic factor levels.

Prenatal loss of father during World War One is predictive of a reduced lifespan in adulthood

Although early-life stress is known to alter health, its long-term consequences on mortality remain largely unknown. Thanks to unique French legislation established in 1917 for war orphans and children of disabled soldiers, we were able to study the adult mortality of individuals born in 1914-1916 whose fathers were killed during World War 1. Vital information and socio-demographic characteristics were extracted manually from historical civil registers for 5,671 children born between 1 August 1914 and 31 December 1916 who were granted the status of "pupille de la Nation" (orphan of the Nation). We used a database comprising 1.4 million deceased soldiers to identify war orphans and collect information on their fathers and then paired each orphan with a nonorphan from the same birth register matched for date of birth, sex, and mother's age at the infant's birth. Mortality between ages 31 and 99 y was analyzed for 2,365 orphan/nonorphan pairs. The mean loss of adult lifespan of orphans who had lost their father before birth was 2.4 y (95% CI: 0.7, 3.9 y) and was the result of increased mortality before age 65 y. Adult lifespan was not reduced when the father's death occurred after the infant's birth. These results support the notion that intrauterine exposure to a major psychological maternal stress can affect human longevity.

Prediction of Possible Biomarkers and Novel Pathways Conferring Risk to Post-Traumatic Stress Disorder

Post-traumatic stress disorder is one of the common mental ailments that is triggered by exposure to traumatic events. Till date, the molecular factors conferring risk to the development of PTSD is not well understood. In this study, we have conducted a meta-analysis followed by hierarchical clustering and functional enrichment, to uncover the potential molecular networks and critical genes which play an important role in PTSD. Two datasets of expression profiles from Peripheral Blood Mononuclear Cells from 62 control samples and 63 PTSD samples were included in our study. In PTSD samples of GSE860 dataset, we identified 26 genes informative when compared with Post-deploy PTSD condition and 58 genes informative when compared with Pre-deploy and Post-deploy PTSD of GSE63878 dataset. We conducted the meta-analysis using Fisher, roP, Stouffer, AW, SR, PR and RP methods in MetaDE package. Results from the rOP method of MetaDE package showed that among these genes, the following showed significant changes including, OR2B6, SOX21, MOBP, IL15, PTPRK, PPBPP2 and SEC14L5. Gene ontology analysis revealed enrichment of these significant PTSD-related genes for cell proliferation, DNA damage and repair (p-value ≤ 0.05). Furthermore, interaction network analysis was performed on these 7 significant genes. This analysis revealed highly connected functional interaction networks with two candidate genes, IL15 and SEC14L5 highly enriched in networks. Overall, from these results, we concluded that these genes can be recommended as some of the potential targets for PTSD.

Role of glutamate receptors and glial cells in the pathophysiology of treatment-resistant depression

Treatment-resistant depression (TRD) causes substantial socioeconomic burden. Although a consensus on the definition of TRD has not yet been reached, it is certain that classic monoaminergic antidepressants are ineffective for TRD. One decade ago, many researchers found ketamine, an N-methyl-d-aspartate receptor (NMDAR) antagonist, to be an alternative to classic monoaminergic antidepressants. The major mechanisms of action of ketamine rapidly induce synaptogenesis in the brain-derived neurotrophic factor (BDNF) pathway. Although excessive glutamatergic neurotransmission and consequent excitotoxicity were considered a major cause of TRD, recent evidence suggests that the extrasynaptic glutamatergic receptor signal pathway mainly contributes to the detrimental effects of TRD. Glial cells such as microglia and astrocytes, early life adversity, and glucocorticoid receptor dysfunction participate in complex cross-talk. An appropriate reuptake of glutamate at the astrocyte is crucial for preventing 'spill-over' of synaptic glutamate and binding to the extrasynaptic NMDA receptor. Excessive microglial activation and the inflammatory process cause astrocyte glutamatergic dysfunction, which in turn activates microglial function. Early life adversity and glucocorticoid receptor dysfunction result in vulnerability to stress in adulthood. A maladaptive response to stress leads to increased glutamatergic release and pro-inflammatory cytokines, which then activate microglia. However, since the role of inflammatory mediators such as pro-inflammatory cytokines is not specific for depression, more disease-specific mechanisms should be identified. Last, although much research has focused on ketamine as an alternative antidepressant for TRD, its long-lasting effectiveness and adverse events have not been rigorously demonstrated. Additionally, evidence suggests that substantial brain abnormalities develop in ketamine abusers. Thus, more investigations for ketamine and other novel glutamatergic agents are needed.

FK506 binding protein 51 integrates pathways of adaptation: FKBP51 shapes the reactivity to environmental change

This review portraits FK506 binding protein (FKBP) 51 as "reactivity protein" and collates recent publications to develop the concept of FKBP51 as contributor to different levels of adaptation. Adaptation is a fundamental process that enables unicellular and multicellular organisms to adjust their molecular circuits and structural conditions in reaction to environmental changes threatening their homeostasis. FKBP51 is known as chaperone and co-chaperone of heat shock protein (HSP) 90, thus involved in processes ensuring correct protein folding in response to proteotoxic stress. In mammals, FKBP51 both shapes the stress response and is calibrated by the stress levels through an ultrashort molecular feedback loop. More recently, it has been linked to several intracellular pathways related to the reactivity to drug exposure and stress. Through its role in autophagy and DNA methylation in particular it influences adaptive pathways, possibly also in a transgenerational fashion. Also see the video abstract here.

The neurobiological basis of human aggression: A review on genetic and epigenetic mechanisms

Aggression is an evolutionary conserved behavior present in most species including humans. Inadequate aggression can lead to long-term detrimental personal and societal effects. Here, we differentiate between proactive and reactive forms of aggression and review the genetic determinants of it. Heritability estimates of aggression in general vary between studies due to differing assessment instruments for aggressive behavior (AB) as well as age and gender of study participants. In addition, especially non-shared environmental factors shape AB. Current hypotheses suggest that environmental effects such as early life stress or chronic psychosocial risk factors (e.g., maltreatment) and variation in genes related to neuroendocrine, dopaminergic as well as serotonergic systems increase the risk to develop AB. In this review, we summarize the current knowledge of the genetics of human aggression based on twin studies, genetic association studies, animal models, and epigenetic analyses with the aim to differentiate between mechanisms associated with proactive or reactive aggression. We hypothesize that from a genetic perspective, the aminergic systems are likely to regulate both reactive and proactive aggression, whereas the endocrine pathways seem to be more involved in regulation of reactive aggression through modulation of impulsivity. Epigenetic studies on aggression have associated non-genetic risk factors with modifications of the stress response and the immune system. Finally, we point to the urgent need for further genome-wide analyses and the integration of genetic and epigenetic information to understand individual differences in reactive and proactive AB. © 2015 Wiley Periodicals, Inc.

Behavioral differences of male Wistar rats from different vendors in vulnerability and resilience to chronic mild stress are reflected in epigenetic regulation and expression of p11

Outbred rat lines such as Wistar rats are commonly used for models of depressive disorders. Such rats arise from random mating schedules. Hence, genetic drift occurs in outbred populations which could lead to genotypic and phenotypic heterogeneity between rats from different vendors. Additionally, vendor specific rearing conditions could contribute to intrastrain variability. In the present study differences in behavioral responses to the chronic mild stress (CMS) model of depression within Wistar rat strains from different vendors are described. DNA methylation studies and mRNA expression analysis of p11 revealed that the behavioral differences between the substrains are reflected at the epigenetic and genetic level. The results suggest that there are breeder-dependent differences in vulnerability to stress in the CMS model of depression, which might bear on the validity of the model and contribute to contradictory findings and difficulties of replication between laboratories. P11 mRNA expression seems to be differently regulated depending on the quality of the stress response evoked by CMS exposure.

Molecular epigenetic switches in neurodevelopment in health and disease

Epigenetic mechanisms encode information above and beyond DNA sequence and play a critical role in brain development and the long-lived effects of environmental cues on the pre- and postnatal brain. Switch-like, rather than graded changes, illustrate par excellence how epigenetic events perpetuate altered activity states in the absence of the initial cue. They occur from early neural development to maturation and can give rise to distinct diseases upon deregulation. Many neurodevelopmental genes harbor bivalently marked chromatin domains, states of balanced inhibition, which guide dynamic “ON or OFF” decisions once the balance is tilted in response to developmental or environmental cues. Examples discussed in this review include neuronal differentiation of embryonic stem cells (ESC) into progenitors and beyond, activation of Kiss1 at puberty onset, and early experience-dependent programming of Avp, a major stress gene. At the genome-scale, genomic imprinting can be epigenetically switched on or off at select genes in a tightly controlled temporospatial manner and provides a versatile mechanism for dosage regulation of genes with important roles in stem cell quiescence or differentiation. Moreover, retrotransposition in neural progenitors provides an intriguing example of an epigenetic-like switch, which is stimulated by bivalently marked neurodevelopmental genes and possibly results in increased genomic flexibility regarding unprecedented challenge. Overall, we propose that molecular epigenetic switches illuminate the catalyzing function of epigenetic mechanisms in guiding dynamic changes in gene expression underpinning robust transitions in cellular and organismal phenotypes as well as in the mediation between dynamically changing environments and the static genetic blueprint.

Inhibition of histone deacetylases enhances the function of serotoninergic neurons in organotypic raphe slice cultures

Inhibition of histone deacetylases (HDACs) is a promising approach for the treatment of mood disorders. However, the effects of HDAC inhibition on the serotonin (5-HT) system, a common target for psychiatric disorders, are poorly understood. Here, we show that a broad-spectrum HDAC inhibitor, trichostatin A (TSA), enhances the function of 5-HT neurons in organotypic raphe slice cultures. Sustained treatment with TSA (1μM) for 2 or 4 days significantly increased the 5-HT tissue content and tryptophan hydroxylase 2 (TPH2) expression, which were accompanied by hyper-acetylation of histone H3 in the promoter region of the TPH2 gene. TSA treatment for 4 days increased the extracellular 5-HT level, which was significantly suppressed in the presence of the selective AMPA receptor (AMPAR) antagonist NBQX. Moreover, the expression of both the AMPAR subunit GluA2 and Ca(2+)/calmodulin-dependent kinase II α (CaMKIIα) mRNAs were significantly increased by TSA treatment. Co-treatment with the CaMKII inhibitors KN-62 and KN-93 prevented the TSA-induced increase in 5-HT release, but had no effect on the increases in 5-HT tissue content. These results suggest that inhibition of HDACs increases 5-HT synthesis and release by epigenetic mechanisms, and that 5-HT release is mediated by the enhancement of AMPAR-mediated excitatory inputs and CaMKII signaling.

Role of mecp2 in experience-dependent epigenetic programming

Mutations in the X-linked gene MECP2, the founding member of a family of proteins recognizing and binding to methylated DNA, are the genetic cause of a devastating neurodevelopmental disorder in humans, called Rett syndrome. Available evidence suggests that MECP2 protein has a critical role in activity-dependent neuronal plasticity and transcription during brain development. Moreover, recent studies in mice show that various posttranslational modifications, notably phosphorylation, regulate Mecp2’s functions in learning and memory, drug addiction, depression-like behavior, and the response to antidepressant treatment. The hypothalamic-pituitary-adrenal (HPA) axis drives the stress response and its deregulation increases the risk for a variety of mental disorders. Early-life stress (ELS) typically results in sustained HPA-axis deregulation and is a major risk factor for stress related diseases, in particular major depression. Interestingly, Mecp2 protein has been shown to contribute to ELS-dependent epigenetic programming of Crh, Avp, and Pomc, all of these genes enhance HPA-axis activity. Hereby ELS regulates Mecp2 phosphorylation, DNA binding, and transcriptional activities in a tissue-specific and temporospatial manner. Overall, these findings suggest MECP2 proteins are so far underestimated and have a more dynamic role in the mediation of the gene-environment dialog and epigenetic programming of the neuroendocrine stress system in health and disease.

Childhood sexual abuse and posttraumatic stress disorder among pregnant and postpartum women: review of the literature

The aims of this review are (i) to summarize and evaluate current knowledge on the association between childhood sexual abuse (CSA) and posttraumatic stress disorder (PTSD) in pregnant and postpartum women, (ii) to provide suggestions for future research on this topic, and (iii) to highlight some clinical implications. Relevant publications were identified through literature searches of four databases (PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, and PsycARTICLES) using keywords such as "child abuse," "posttraumatic stress," "pregnancy," and "postpartum". Five studies were included in this review. Findings across all studies were consistent with higher prevalence of PTSD diagnosis or symptomatology among women with history of CSA. However, only findings from two studies were statistically significant. One study observed higher overall PTSD scores in women with CSA history compared to women with non-CSA trauma history or no trauma history during pregnancy (mean ± SD 1.47 (0.51) vs. 1.33 (0.41) vs. 1.22 (0.29), p < 0.001), at 2 months postpartum (mean ± SD 1.43 (0.49) vs. 1.26 (0.38) vs. 1.19 (0.35), p < 0.001), and at 6 months postpartum (mean ± SD 1.36 (1.43) vs. 1.20 (0.33) vs. 1.14 (0.27), p < 0.001). Another study observed that the prevalence of PTSD during pregnancy was 4.1 % in women with no history of physical or sexual abuse, 11.4 % in women with adult physical or sexual abuse history, 16.0 % in women with childhood physical or sexual abuse history, and 39.0 % in women exposed to both childhood and adult physical or sexual abuse (p < 0.001); in a subsequent analysis, the investigators reported that pregnant women with PTSD had over 5-fold odds of having a history of childhood completed rape compared to counterparts without PTSD (OR = 5.3, 95 % CI 3.2, 8.7). Overall, available evidence suggests positive associations of CSA with clinical PTSD or PTSD symptomatology among pregnant and postpartum women.

Neonatal handling (resilience) attenuates water-avoidance stress induced enhancement of chronic mechanical hyperalgesia in the rat

Chronic stress is well known to exacerbate pain. We tested the hypothesis that neonatal handling, which induces resilience to the negative impact of stress by increasing the quality and quantity of maternal care, attenuates the mechanical hyperalgesia produced by water-avoidance stress in the adult rat. Neonatal male rats underwent the handling protocol on postnatal days 2-9, weaned at 21 days and tested for muscle mechanical nociceptive threshold at postnatal days 50-75. Decrease in mechanical nociceptive threshold in skeletal muscle in adult rats, produced by exposure to water-avoidance stress, was significantly attenuated by neonatal handling. Neonatal handling also attenuated the mechanical hyperalgesia produced by intramuscular administration of the pronociceptive inflammatory mediator, prostaglandin E2 in rats exposed as adults to water-avoidance stress. Neonatal handling, which induces a smaller corticosterone response in adult rats exposed to a stressor as well as changes in central nervous system neurotransmitter systems, attenuates mechanical hyperalgesia produced by water-avoidance stress and enhanced prostaglandin hyperalgesia in adult animals.

Peripartum depression and anxiety as an integrative cross domain target for psychiatric preventative measures

Exposure to high levels of early life stress has been identified as a potent risk factor for neurodevelopmental delays in infants, behavioral problems and autism in children, but also for several psychiatric illnesses in adulthood, such as depression, anxiety, autism, and posttraumatic stress disorder. Despite having robust adverse effects on both mother and infant, the pathophysiology of peripartum depression and anxiety are poorly understood. The objective of this review is to highlight the advantages of using an integrated approach addressing several behavioral domains in both animal and clinical studies of peripartum depression and anxiety. It is postulated that a greater focus on integrated cross domain studies will lead to advances in treatments and preventative measures for several disorders associated with peripartum depression and anxiety.

Emerging role of microRNAs in major depressive disorder: diagnosis and therapeutic implications

Major depressive disorder (MDD) is a major public health concern. Despite tremendous advances, the pathogenic mechanisms associated with MDD are still unclear. Moreover, a significant number of MDD subjects do not respond to the currently available medication. MicroRNAs (miRNAs) are a class of small noncoding RNAs that control gene expression by modulating translation, messenger RNA (mRNA) degradation, or stability of mRNA targets. The role of miRNAs in disease pathophysiology is emerging rapidly. Recent studies demonstrating the involvement of miRNAs in several aspects of neural plasticity, neurogenesis, and stress response, and more direct studies in human postmortem brain provide strong evidence that miRNAs can not only play a critical role in MDD pathogenesis, but can also open up new avenues for the development of therapeutic targets. Circulating miRNAs are now being considered as possible biomarkers in disease pathogenesis and in monitoring therapeutic responses because of the presence and/or release of miRNAs in blood cells as well as in other peripheral tissues. In this review, these aspects are discussed in a comprehensive and critical manner.

Serotonin, tryptophan metabolism and the brain-gut-microbiome axis

The brain-gut axis is a bidirectional communication system between the central nervous system and the gastrointestinal tract. Serotonin functions as a key neurotransmitter at both terminals of this network. Accumulating evidence points to a critical role for the gut microbiome in regulating normal functioning of this axis. In particular, it is becoming clear that the microbial influence on tryptophan metabolism and the serotonergic system may be an important node in such regulation. There is also substantial overlap between behaviours influenced by the gut microbiota and those which rely on intact serotonergic neurotransmission. The developing serotonergic system may be vulnerable to differential microbial colonisation patterns prior to the emergence of a stable adult-like gut microbiota. At the other extreme of life, the decreased diversity and stability of the gut microbiota may dictate serotonin-related health problems in the elderly. The mechanisms underpinning this crosstalk require further elaboration but may be related to the ability of the gut microbiota to control host tryptophan metabolism along the kynurenine pathway, thereby simultaneously reducing the fraction available for serotonin synthesis and increasing the production of neuroactive metabolites. The enzymes of this pathway are immune and stress-responsive, both systems which buttress the brain-gut axis. In addition, there are neural processes in the gastrointestinal tract which can be influenced by local alterations in serotonin concentrations with subsequent relay of signals along the scaffolding of the brain-gut axis to influence CNS neurotransmission. Therapeutic targeting of the gut microbiota might be a viable treatment strategy for serotonin-related brain-gut axis disorders.

Mineralocorticoid receptor and heat shock protein expression levels in peripheral lymphocytes from war trauma-exposed men with and without PTSD

Alterations in the number and functional status of mineralocorticoid (MR) and glucocorticoid receptors (GR) may contribute to vulnerability to posttraumatic stress disorder (PTSD). Corticosteroid receptors are chaperoned by heat shock proteins Hsp90 and Hsp70. We examined relations between corticosteroid receptor and heat shock protein expression levels, and related them with war trauma exposure, PTSD and resilience to PTSD. Relative levels of MR, Hsp90 and Hsp70 were determined by immunoblotting in lymphocytes from war trauma-exposed men with current PTSD (current PTSD group, n=113), with life-time PTSD (life-time PTSD group, n=61) and without PTSD (trauma control group, n=88), and from non-traumatized healthy controls (healthy control group, n=85). Between-group differences in MR, Hsp90 and Hsp70 levels and in MR/GR ratio were not observed. The level of MR was correlated with both Hsp90 and Hsp70 levels in trauma control and healthy control groups. On the other hand, GR level was correlated only with Hsp90 level, and this correlation was evident in current PTSD and trauma control groups. In conclusion, PTSD and exposure to trauma are not related to changes in lymphocyte MR, Hsp90 or Hsp70 levels, but may be associated with disturbances in corticosteroid receptors interaction with heat shock proteins.

Early-life stress impacts the developing hippocampus and primes seizure occurrence: cellular, molecular, and epigenetic mechanisms

Early-life stress includes prenatal, postnatal, and adolescence stress. Early-life stress can affect the development of the hypothalamic-pituitary-adrenal (HPA) axis, and cause cellular and molecular changes in the developing hippocampus that can result in neurobehavioral changes later in life. Epidemiological data implicate stress as a cause of seizures in both children and adults. Emerging evidence indicates that both prenatal and postnatal stress can prime the developing brain for seizures and an increase in epileptogenesis. This article reviews the cellular and molecular changes encountered during prenatal and postnatal stress, and assesses the possible link between these changes and increases in seizure occurrence and epileptogenesis in the developing hippocampus. In addititon, the priming effect of prenatal and postnatal stress for seizures and epileptogenesis is discussed. Finally, the roles of epigenetic modifications in hippocampus and HPA axis programming, early-life stress, and epilepsy are discussed.

Age- and sex-dependent effects of early life stress on hippocampal neurogenesis

Early life stress is a well-documented risk factor for the development of psychopathology in genetically predisposed individuals. As it is hard to study how early life stress impacts human brain structure and function, various animal models have been developed to address this issue. The models discussed here reveal that perinatal stress in rodents exerts lasting effects on the stress system as well as on the structure and function of the brain. One of the structural parameters strongly affected by perinatal stress is adult hippocampal neurogenesis. Based on compiled literature data, we report that postnatal stress slightly enhances neurogenesis until the onset of puberty in male rats; when animals reach adulthood, neurogenesis is reduced as a consequence of perinatal stress. By contrast, female rats show a prominent reduction in neurogenesis prior to the onset of puberty, but this effect subsides when animals reach young adulthood. We further present preliminary data that transient treatment with a glucocorticoid receptor antagonist can normalize cell proliferation in maternally deprived female rats, while the compound had no effect in non-deprived rats. Taken together, the data show that neurogenesis is affected by early life stress in an age- and sex-dependent manner and that normalization may be possible during critical stages of brain development.

microRNAs as Biomarker in Depression Pathogenesis

Major depressive disorder (MDD) is a major health concern with alarming rates of completed suicide. Thus, it is important to understand the pathophysiology of this disorder. In addition, disturbingly high rates of relapse and low rates of recovery make it urgent not only to develop targeted treatments but to identify biomarkers that can predict treatment response for individual patients. MicroRNAs (miRNAs) are a class of small non-coding RNAs that control gene expression by modulating translation, mRNA degradation or stability of mRNA targets. The role of miRNAs in disease pathophysiology is emerging rapidly. Several recent studies have suggested the possible role of miRNAs in synaptic plasticity, neurogenesis, and stress response, all implicated in MDD. Emerging studies showthe direct role of miRNAs in the development of depression phenotype. More recently, the role of miRNAs in prognosis and treatment response is being considered for various disease pathophysiology, including MDD. The review discusses the recent studies demonstrating the role of miRNAs in MDD and whether miRNA can be used as a biomarker for MDD pathogenesis and treatment response.