Blood mononuclear cell gene expression signature of postpartum depression

Decreased mononuclear cell NR3C1 SKA2 and FKPB5 expression levels among adult survivors of suicide bombing terror attacks in childhood are associated with the development of PTSD

Life threatening trauma and the development of PTSD during childhood, may each associate with transcriptional perturbation of immune cell glucocorticoid reactivity, yet their separable longer term contributions are less clear. The current study compared resting mononuclear cell gene expression levels of the nuclear receptor, subfamily 3, member 1 (NR3C1) coding the glucocorticoid receptor, its trans-activator spindle and kinetochore-associated protein 2 (SKA2), and its co-chaperon FKBP prolyl isomerase 5 (FKBP5), between a cohort of young adults first seen at the Hadassah Emergency Department (ED) after surviving a suicide bombing terror attack during childhood, and followed longitudinally over the years, and matched healthy controls not exposed to life threatening trauma. While significant reductions in mononuclear cell gene expression levels were observed among young adults for all three transcripts following early trauma exposure, the development of subsequent PTSD beyond trauma exposure, accounted for a small but significant portion of the variance in each of the three transcripts. Long-term perturbation in the expression of immune cell glucocorticoid response transcripts persists among young adults who develop PTSD following life threatening trauma exposure in childhood, denoting chronic dysregulation of immune stress reactivity.

Identification and characterization of noncoding RNAs-associated competing endogenous RNA networks in major depressive disorder

BACKGROUND

Major depressive disorder (MDD) is a common and serious mental illness. Many novel genes in MDD have been characterized by high-throughput methods such as microarrays or sequencing. Recently, noncoding RNAs (ncRNAs) were suggested to be involved in the complicated environmental-genetic regulatory network of MDD occurrence; however, the interplay among RNA species, including protein-coding RNAs and ncRNAs, in MDD remains unclear.

AIM

To investigate the RNA expression datasets downloaded from a public database and construct a network based on differentially expressed long noncoding RNA (lncRNAs), microRNAs (miRNAs), and mRNAs between MDD and controls.

METHODS

Gene expression data were searched in NCBI Gene Expression Omnibus using the search term “major depressive disorder.” Six array datasets from humans were related to the search term: GSE19738, GSE32280, GSE38206, GSE52790, GSE76826, and GSE81152. These datasets were processed for initial assessment and subjected to quality control and differential expression analysis. Differentially expressed lncRNAs, miRNAs, and mRNAs were determined, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed, and protein-protein interaction network was generated. The results were analyzed for their association with MDD.

RESULTS

After analysis, 3 miRNAs, 12 lncRNAs, and 33 mRNAs were identified in the competing endogenous RNA network. Two of these miRNAs were earlier shown to be involved in psychiatric disorders, and differentially expressed mRNAs were found to be highly enriched in pathways related to neurogenesis and neuroplasticity as per Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. The expression of hub gene fatty acid 2-hydroxylase was enriched, and the encoded protein was found to be involved in myelin formation, indicating that neurological development and signal transduction are involved in MDD pathogenesis.

CONCLUSION

The present study presents candidate ncRNAs involved in the neurogenesis and neuroplasticity pathways related to MDD.

Immune transcriptional profiles in mothers with clinically elevated depression and anxiety symptoms several years post-delivery

BACKGROUND

Most research on maternal mental health focuses on the perinatal period and does not extend beyond 12 months postpartum. However, emerging evidence suggests that for some women (30%-50%), psychological symptoms may persist beyond the first year postpartum or even emerge later increasing the risk of chronic mood and anxiety symptoms. Despite the high prevalence rates and devastating maternal-child consequences, studies examining maternal depression, anxiety, and post-traumatic stress disorder (PTSD) beyond the first year postpartum are rare and our understanding of the underlying biological mechanisms is incomplete. Inflammatory processes are thought to be involved in the pathophysiology of depression, anxiety, & PTSD outside of the postpartum period. Therefore, the purpose of the current investigation was to examine the relationship between depression, anxiety, and PTSD two to three years post-delivery, and transcriptional control pathways relevant to inflammatory and antiviral processes.

METHODS

Women over 18 years of age enrolled in ongoing research studies at Cedars Sinai Medical Center who were 2-3 years postpartum were invited to participate in the current study. Women (N = 33) reported on their levels of depression, anxiety, and PTSD and provided a blood sample approximately 2-3 years post-delivery. Bioinformatic analyses of differential gene expression (DGEs) to infer transcription factor activity were used. Gene expression was assayed by RNA sequencing and TELiS bioinformatics analysis of transcription factor-binding motifs in the promoters of differentially expressed genes.

RESULTS

DGE analyses revealed that women with clinically elevated symptoms of depression, anxiety and PTSD (n = 16) showed upregulation of genes activated by transcription control pathways associated with inflammation (NF-_Κ B, p = 0.004; JUN, p = 0.02), including ꞵ-adrenergic responsive CREB (p = 0.01) and reduced activation of genes associated with the antiviral response (IRFs, p = 0.02) and the glucocorticoid signaling pathway (GR, p = 0.02) compared to women without clinical symptoms (n = 17).

CONCLUSIONS

This is one of the first investigations into the immune signaling pathways involved in depression, anxiety, and PTSD two to three years post-delivery. The results of this study suggest that clinically elevated symptoms of depression, anxiety, and PTSD two to three years post-delivery are associated with a gene expression profile characterized by upregulated expression of pro-inflammatory genes and downregulated expression of antiviral genes. The data also point to two potential stress responsive pathways linking symptoms to increased inflammatory signaling in immune cells: sympathetic nervous system mediated ꞵ-adrenergic signaling and reduced hypothalamic pituitary adrenal axis activity. Together, these findings highlight the need for investigations into maternal mental health beyond the first year postpartum. This article is protected by copyright. All rights reserved.

Environmental risk factors, protective factors, and biomarkers for postpartum depressive symptoms: an umbrella review

We performed an umbrella review on environmental risk/protective factors and biomarkers for postpartum depressive symptoms to establish a hierarchy of evidence. We systematically searched PubMed, Embase, and the Cochrane Database of Systematic Reviews from inception until 12 January 2021. We included systematic reviews providing meta-analyses related to our research objectives. Methodological quality was assessed by AMSTAR 2, and the certainty of evidence was evaluated by GRADE. This review was registered in PROSPERO (CRD42021230784). We identified 30 articles, which included 45 environmental risk/protective factors (154,594 cases, 7,302,273 population) and 9 biomarkers (2018 cases, 16,757 population). The credibility of evidence was convincing (class I) for antenatal anxiety (OR 2.49, 1.91-3.25) and psychological violence (OR 1.93, 1.54-2.42); and highly suggestive (class II) for intimate partner violence experience (OR 2.86, 2.12-3.87), intimate partner violence during pregnancy (RR 2.81, 2.11-3.74), smoking during pregnancy (OR 2.39, 1.78-3.2), history of premenstrual syndrome (OR 2.2, 1.81-2.68), any type of violence experience (OR 2.04, 1.72-2.41), primiparity compared to multiparity (RR 1.76, 1.59-1.96), and unintended pregnancy (OR 1.53, 1.35-1.75).

Genetic variants in the genes of the sex steroid hormone metabolism and depressive symptoms during and after pregnancy

PURPOSE

The aim of this study was to conduct an association analysis of depressive symptoms and polymorphisms in the ESR1, PGR, CYP19A1, and COMT genes in pregnant and postpartum women.

METHODS

The Franconian Maternal Health Evaluation Study (FRAMES) recruited healthy pregnant women prospectively for assessment of maternal and fetal health. The German version of the 10-item Edinburgh Postnatal Depression Scale (EPDS) was completed at three time points in this prospective cohort study. Visit 1 was at study entry in the third trimester of pregnancy, visit 2 was shortly after birth, and visit 3 was 6-8 months after birth. Germline DNA and depression measurements from 361 pregnant women were available for analysis. Six single nucleotide polymorphisms (SNPs) in the above-mentioned genes were genotyped. After reconstruction of haplotypes for PGR (rs1042838 and rs10895068) and CYP19A1 (rs10046 and rs4646), a multifactorial linear mixed model was applied to the data to describe the association between haplotypes and depression values. The single SNPs for ESR1 (rs488133) and COMT (rs4680) were analyzed separately using linear mixed models analogously.

RESULTS

The mean antepartum EPDS measurement was 5.1, the mean postpartal measurement after 48-72 h was 3.5, and the mean value 6-8 months postpartum was 4.2. The SNPs in PGR were reconstructed into three haplotypes. The most common haplotype was GG, with 63.43% of patients carrying two copies and 33.52% carrying one copy. For haplotype GA, the group of carriers of two copies (0.28%) was combined with the carriers of one copy (9.70%). Haplotype reconstruction using CYP19A1 SNPs resulted in three haplotypes. The most common haplotype was TC, with 25.48% of patients carrying two copies and 51.52% one copy. None of the haplotype blocks and neither of the two single SNPs showed any significant associations with EPDS values.

CONCLUSIONS

The candidate haplotypes analyzed in PGR and CYP19A1 and single SNPs in ESR1 and COMT did not show any association with depression scores as assessed by EPDS in this cohort of healthy unselected pregnant women.

Identification of Key Modules and Genes Associated with Major Depressive Disorder in Adolescents

Major depressive disorder (MDD) is a leading cause of disability worldwide. Adolescence is a crucial period for the occurrence and development of depression. There are essential distinctions between adolescent and adult depression patients, and the etiology of depressive disorder is unclear. The interactions of multiple genes in a co-expression network are likely to be involved in the physiopathology of MDD. In the present study, RNA-Seq data of mRNA were acquired from the peripheral blood of MDD in adolescents and healthy control (HC) subjects. Co-expression modules were constructed via weighted gene co-expression network analysis (WGCNA) to investigate the relationships between the underlying modules and MDD in adolescents. In the combined MDD and HC groups, the dynamic tree cutting method was utilized to assign genes to modules through hierarchical clustering. Moreover, functional enrichment analysis was conducted on those co-expression genes from interested modules. The results showed that eight modules were constructed by WGCNA. The blue module was significantly associated with MDD after multiple comparison adjustment. Several Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with stress and inflammation were identified in this module, including histone methylation, apoptosis, NF-kappa β signaling pathway, and TNF signaling pathway. Five genes related to inflammation, immunity, and the nervous system were identified as hub genes: CNTNAP3, IL1RAP, MEGF9, UBE2W, and UBE2D1. All of these findings supported that MDD was associated with stress, inflammation, and immune responses, helping us to obtain a better understanding of the internal molecular mechanism and to explore biomarkers for the diagnosis or treatment of depression in adolescents.

Immune System Alterations and Postpartum Mental Illness: Evidence From Basic and Clinical Research

The postpartum period is a time associated with high rates of depression and anxiety as well as greater risk for psychosis in some women. A growing number of studies point to aberrations in immune system function as contributing to postpartum mental illness. Here we review evidence from both clinical and animal models suggesting an immune component to postpartum depression, postpartum anxiety, and postpartum psychosis. Thus far, clinical data primarily highlights changes in peripheral cytokine signaling in disease etiology, while animal models have begun to provide insight into the immune environment of the maternal brain and how central inflammation may also be contributing to postpartum mental illnesses. Further research investigating peripheral and central immune function, along with neural and endocrine interactions, will be important in successfully developing novel prevention and treatment strategies for these serious disorders that impact a large portion of new mothers.

Resting mononuclear cell NR3C1 and SKA2 expression levels predict blunted cortisol reactivity to combat training stress among elite army cadets exposed to childhood adversity

Childhood adversity (CA) may alter reactivity to stress throughout life, increasing risk for psychiatric and medical morbidity, yet long-term correlates of milder CA levels among high functioning healthy adolescents are less studied. The current study examined the prevalence and impact of CA exposure among a cohort of healthy motivated elite parachute unit volunteers, prospectively assessed at rest and at the height of an intensive combat-simulation exposure. We found significantly reduced gene expression levels in resting mononuclear cell nuclear receptor, subfamily 3, member 1 (NR3C1), and its transactivator spindle and kinetochore-associated protein 2 (SKA2), that predict blunted cortisol reactivity to combat-simulation stress among CA exposed adolescents. Long-term alterations in endocrine immune indices, subjective distress, and executive functions persist among healthy high functioning adolescents following milder CA exposure, and may promote resilience or vulnerability to later real-life combat exposure.

Can (immune and other) gene expression help us to treat depression?

It is becoming clearer that it might be a combination of different biological processes such as genetic, environmental, and psychological factors, together with immune system, stress response, brain neuroplasticity and the regulation of neurotransmitters, that leads to the development of major depressive disorder (MDD). A growing number of studies have tried to investigate the underlying mechanisms of MDD by analysing the expression levels of genes (mRNA) involved in such biological processes. In this review, I have highlighted a possible key role that gene expression might play in the treatment of MDD. This is critical because many patients do not respond to antidepressant treatment or can experience side effects, causing treatment to be interrupted. Unfortunately, selecting the best antidepressant for each individual is still largely a matter of making an informed guess.

Psychosocial experiences modulate asthma-associated genes through gene-environment interactions

Social interactions and the overall psychosocial environment have a demonstrated impact on health, particularly for people living in disadvantaged urban areas. Here, we investigated the effect of psychosocial experiences on gene expression in peripheral blood immune cells of children with asthma in Metro Detroit. Using RNA-sequencing and a new machine learning approach, we identified transcriptional signatures of 19 variables including psychosocial factors, blood cell composition, and asthma symptoms. Importantly, we found 169 genes associated with asthma or allergic disease that are regulated by psychosocial factors and 344 significant gene-environment interactions for gene expression levels. These results demonstrate that immune gene expression mediates the link between negative psychosocial experiences and asthma risk.

Gene expression studies in Depression development and treatment: an overview of the underlying molecular mechanisms and biological processes to identify biomarkers

A combination of different risk factors, such as genetic, environmental and psychological factors, together with immune system, stress response, brain neuroplasticity and the regulation of neurotransmitters, is thought to lead to the development of major depressive disorder (MDD). A growing number of studies have tried to investigate the underlying mechanisms of MDD by analysing the expression levels of genes involved in such biological processes. These studies have shown that MDD is not just a brain disorder, but also a body disorder, and this is mainly due to the interplay between the periphery and the Central Nervous System (CNS). To this purpose, most of the studies conducted so far have mainly dedicated to the analysis of the gene expression levels using postmortem brain tissue as well as peripheral blood samples of MDD patients. In this paper, we reviewed the current literature on candidate gene expression alterations and the few existing transcriptomics studies in MDD focusing on inflammation, neuroplasticity, neurotransmitters and stress-related genes. Moreover, we focused our attention on studies, which have investigated mRNA levels as biomarkers to predict therapy outcomes. This is important as many patients do not respond to antidepressant medication or could experience adverse side effects, leading to the interruption of treatment. Unfortunately, the right choice of antidepressant for each individual still remains largely a matter of taking an educated guess.

Postpartum Depression: Current Status and Possible Identification Using Biomarkers

Postpartum depression (PPD) is a serious health issue that can affect about 15% of the female population within after giving birth. It often conveys significant negative consequences to the offsprings. The symptoms and risk factors are somewhat similar to those found in non-postpartum depression. The main difference resides in the fact that PPD is triggered by postpartum specific factors, including especially biological changes in the hormone levels. Patients are usually diagnosed using a questionnaire onsite or in a clinic. Treatment of PPD often involves psychotherapy and antidepressant medications. In recent years, there have been more researches on the identification of biological markers for PPD. In this review, we will focus on the current research status of PPD, with an emphasis on the recent progress made on the identification of PPD biomarkers.

Pregnancy, postpartum and parity: Resilience and vulnerability in brain health and disease

Risk and resilience in brain health and disease can be influenced by a variety of factors. While there is a growing appreciation to consider sex as one of these factors, far less attention has been paid to sex-specific variables that may differentially impact females such as pregnancy and reproductive history. In this review, we focus on nervous system disorders which show a female bias and for which there is data from basic research and clinical studies pointing to modification in disease risk and progression during pregnancy, postpartum and/or as a result of parity: multiple sclerosis (MS), depression, stroke, and Alzheimer's disease (AD). In doing so, we join others (Shors, 2016; Galea et al., 2018a) in aiming to illustrate the importance of looking beyond sex in neuroscience research.

Small cells with big implications: Microglia and sex differences in brain development, plasticity and behavioral health

Brain sex differences are programmed largely by sex hormone secretions and direct sex chromosome effects in early life, and are subsequently modulated by early life experiences. The brain's resident immune cells, called microglia, actively contribute to brain development. Recent research has shown that microglia are sexually dimorphic, especially during early life, and may participate in sex-specific organization of the brain and behavior. Likewise, sex differences in immune cells and their signaling in the adult brain have been found, although in most cases their function remains unclear. Additionally, immune cells and their signaling have been implicated in many disorders in which brain development or plasticity is altered, including autism, schizophrenia, pain disorders, major depression, and postpartum depression. This review summarizes what is currently known about sex differences in neuroimmune function in development and during other major phases of brain plasticity, as well as the current state of knowledge regarding sex-specific neuroimmune function in psychiatric disorders.

Postpartum Depression: Pathophysiology, Treatment, and Emerging Therapeutics

Postpartum depression (PPD) is common, disabling, and treatable. The strongest risk factor is a history of mood or anxiety disorder, especially having active symptoms during pregnancy. As PPD is one of the most common complications of childbirth, it is vital to identify best treatments for optimal maternal, infant, and family outcomes. New understanding of PPD pathophysiology and emerging therapeutics offer the potential for new ways to add to current medications, somatic treatments, and evidence-based psychotherapy. The benefits and potential harms of treatment, including during breastfeeding, are presented.

Integrated profiling of phenotype and blood transcriptome for stress vulnerability and depression

Etiology of depression and its vulnerability remains elusive. Using a latent profile analysis on dimensional personality traits, we previously identified 3 different phenotypes in the general population, namely stress-resilient, -vulnerable, and -resistant groups. Here we performed microarray-based blood gene expression profiling of these 3 groups (n = 20 for each group) in order to identify genes involved in stress vulnerability as it relates to the risk of depression. Identified differentially expressed genes among the groups were most markedly enriched in ribosome-related pathways. These ribosomal genes, which included ribosomal protein L17 (RPL17) and ribosomal protein L34 (RPL34), were upregulated in relation to the stress vulnerability. Protein-protein interaction and correlational co-expression analyses of the differentially expressed genes/non-coding RNAs consistently showed that functional networks involving ribosomes were affected. The significant upregulation of RPL17 and RPL34 was also observed in depressed patients compared to healthy controls, as confirmed in 2 independent case-control datasets by using pooled microarray data and qPCR experiments (total number of subjects was 122 and 166, respectively). Moreover, the upregulation of RPL17 and RPL34 was most marked in DSM-IV major depressive disorder, followed by in bipolar disorder, and then in schizophrenia, suggesting some diagnostic specificity of these markers as well as their general roles in stress vulnerability. These results suggest that ribosomal genes, particularly RPL17 and RPL34, can play integral roles in stress vulnerability and depression across nonclinical and clinical conditions. This study presents an opportunity to understand how multiple psychological traits and underlying molecular mechanisms interact to render individuals vulnerable to depression.

Gene expression profile in peripheral blood mononuclear cells of postpartum depression patients

Postpartum depression (PPD) is a common mental health problem that causes maternal suffering and various negative consequences for offspring. The pathogenesis of PPD and the causes of consequences for offspring remain largely unknown. Here, we applied RNA sequencing to sequence the whole transcriptomes of peripheral blood mononuclear cells (PBMCs) from PPD patients (Edinburgh Postnatal Depression Scale [EPDS] score ≥13) and control subjects (EPDS = 0). We found that PPD was positively correlated with multiple genes involved in energy metabolism, neurodegenerative diseases and immune response, while negatively correlated with multiple genes in mismatch repair and cancer-related pathways. Remarkably, genes associated with appetite regulation and nutrient response were differentially expressed between PPD and control subjects. Then, we employed a postnatal growth retardation model by repeated immobilization stress (IS) stimulation to maternal mice. The expression of appetite regulation and nutrient response-related genes in the PBMCs of IS mice and in the hypothalamus of their offspring were also affected. In conclusion, this study provides a comprehensive characterization of the PBMCs transcriptome in PPD and suggests that maternal stress may affect appetite regulation and nutrient response in the hypothalamus of offspring mice.

Immune system aberrations in postpartum psychosis: An immunophenotyping study from a tertiary care neuropsychiatric hospital in India

Postpartum psychosis (PP) is associated with significant morbidity to both mother and infant. Immune system dysregulation during PP is reported in recent studies. This study attempted to determine immune signatures associated with first-onset PP by flow cytometry. Peripheral blood showed decreased naive CD4 and CD8 T cells, while activated CD8 and memory regulatory T cells (Tregs) were increased in women with PP as against healthy controls. The CD14^-CD16⁺non-classical monocytes, CD11c+myeloid DCs and cytotoxic CD56^dimCD16⁺ were reduced, while CD56^brtCD16^+/-regulatory NK cells were elevated in women with PP. The variations in immune cell subsets highlight the generalized immune dysregulation in PP.

Differential gene expression in patients with subsyndromal symptomatic depression and major depressive disorder

Background

Subsyndromal symptomatic depression (SSD) is a subtype of subthreshold depressive and can lead to significant psychosocial functional impairment. Although the pathogenesis of major depressive disorder (MDD) and SSD still remains poorly understood, a set of studies have found that many same genetic factors play important roles in the etiology of these two disorders. Nowadays, the differential gene expression between MDD and SSD is still unknown. In our previous study, we compared the expression profile and made the classification with the leukocytes by using whole-genome cRNA microarrays among drug-free first-episode subjects with SSD, MDD and matched healthy controls (8 subjects in each group), and finally determined 48 gene expression signatures. Based on these findings, we further clarify whether these genes mRNA was different expressed in peripheral blood in patients with SSD, MDD and healthy controls (60 subjects respectively)

Method

With the help of the quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR), we gained gene relative expression levels among the three groups.

Results

We found that there are three of the forty eight co-regulated genes had differential expression in peripheral blood among the three groups, which are CD84, STRN, CTNS gene (F = 3.528, p = 0.034; F = 3.382, p = 0.039; F = 3.801, p = 0.026, respectively) while there were no significant differences for other genes.

Conclusion

CD84, STRN, CTNS gene may have significant value for performing diagnostic functions and classifying SSD, MDD and healthy controls.

A survey of neuroimmune changes in pregnant and postpartum female rats

During pregnancy and the postpartum period, the adult female brain is remarkably plastic exhibiting modifications of neurons, astrocytes and oligodendrocytes. However, little is known about how microglia, the brain's innate immune cells, are altered during this time. In the current studies, microglial density, number and morphological phenotype were analyzed within multiple regions of the maternal brain that are known to show neural plasticity during the peripartum period and/or regulate peripartum behavioral changes. Our results show a significant reduction in microglial density during late pregnancy and the early-mid postpartum period in the basolateral amygdala, medial prefrontal cortex, nucleus accumbens shell and dorsal hippocampus. In addition, microglia numbers were reduced postpartum in all four brain regions, and these reductions occurred primarily in microglia with a thin, ramified morphology. Across the various measures, microglia in the motor cortex were unaffected by reproductive status. The peripartum decrease in microglia may be a consequence of reduced proliferation as there were fewer numbers of proliferating microglia, and no changes in apoptotic microglia, in the postpartum hippocampus. Finally, hippocampal concentrations of the cytokines interleukin (IL)-6 and IL-10 were increased postpartum. Together, these data point to a shift in the maternal neuroimmune environment during the peripartum period that could contribute to neural and behavioral plasticity occurring during the transition to motherhood.

Distinctive gene expression profile in women with history of postpartum depression

Postpartum depression (PPD) is a disease which incorporates a variety of depressive states differing in nature and severity. To assist in the understanding of the pathogenesis of the disease, we aimed to ascertain a molecular mechanism underlying PPD development. We applied microarray technology to characterize gene expression of euthymic women with a history of PPD and compared the results with healthy controls. Our study demonstrated that women who considered euthymic on a clinical level, in fact, had an altered molecular profile when compared to participants with no PPD history. We identified nine genes significantly distinguished expression in post- depressive women; they may serve as a diagnostic tool for the detection of a predisposition to PPD. Our findings contribute significantly to the understanding of PPD etiology and its pathogenesis, offer a plausible explanation for the risk of the PPD recurrence, and may also contribute to clinical treatment.

Alterations in leukocyte transcriptional control pathway activity associated with major depressive disorder and antidepressant treatment

Major depressive disorder (MDD) is associated with a significantly elevated risk of developing serious medical illnesses such as cardiovascular disease, immune impairments, infection, dementia and premature death. Previous work has demonstrated immune dysregulation in subjects with MDD. Using genome-wide transcriptional profiling and promoter-based bioinformatic strategies, we assessed leukocyte transcription factor (TF) activity in leukocytes from 20 unmedicated MDD subjects versus 20 age-, sex- and ethnicity-matched healthy controls, before initiation of antidepressant therapy, and in 17 of the MDD subjects after 8 weeks of sertraline treatment. In leukocytes from unmedicated MDD subjects, bioinformatic analysis of transcription control pathway activity indicated an increased transcriptional activity of cAMP response element-binding/activating TF (CREB/ATF) and increased activity of TFs associated with cellular responses to oxidative stress (nuclear factor erythroid-derived 2-like 2, NFE2l2 or NRF2). Eight weeks of antidepressant therapy was associated with significant reductions in Hamilton Depression Rating Scale scores and reduced activity of NRF2, but not in CREB/ATF activity. Several other transcriptional regulation pathways, including the glucocorticoid receptor (GR), nuclear factor kappa-B cells (NF-κB), early growth response proteins 1-4 (EGR1-4) and interferon-responsive TFs, showed either no significant differences as a function of disease or treatment, or activities that were opposite to those previously hypothesized to be involved in the etiology of MDD or effective treatment. Our results suggest that CREB/ATF and NRF2 signaling may contribute to MDD by activating immune cell transcriptome dynamics that ultimately influence central nervous system (CNS) motivational and affective processes via circulating mediators.

Perinatal Major Depression Biomarkers: A systematic review

Postpartum depression, now termed perinatal depression by the DSM-5, is a clinically relevant disorder reaching 15% of incidence. Although it is quite frequent and associated with high social dysfunction, only recently its underpinning biological pathways have been explored, while multiple and concomitant risk factors have been identified (e.g. psychosocial stress). Peripartum depression usually has its onset during the third trimester of pregnancy or in the postpartum, being one of the most common medical complications in new mothers. Purpose of the present review is to summarize the state of art of biological biomarkers involved in the pathogenesis of perinatal depression, in view of the fact that suboptimal prenatal milieu can induce permanent damage in subsequent offspring life and have a negative impact on mother-child relationship. Furthermore, parents' biological changes due to medical/psychiatric disorders or stress exposure could influence offspring life: a concept known as 'intergenerational transmission', acting by variations into gametes and the gestational uterine environment. Given the evidence that perinatal mental disorders involve risks for the mother and offspring, the search for reliable biomarkers in high-risk mothers actually represents a medical priority to prevent perinatal depression.

Longitudinal monitoring of the serotonin transporter gene expression to assess major depressive episode evolution

BACKGROUND

Mood disorders are frequently characterized by uncertain prognosis and studying mRNA expression variations in blood cells represents a promising avenue of identifying biomarkers for mood disorders. State-dependent gene expression variations have been described during a major depressive episode (MDE), in particular for SLC6A4 mRNA, but how this transcript varies in relation to MDE evolution remains unclear. In this study, we prospectively assessed time trends of SCL6A4 mRNA expression in responder and nonresponder patients.

METHODS

We examined SLC6A4 mRNA expression in blood samples from 13 patients treated for severe MDE and their matched controls by reverse transcription and quantitative PCR. All subjects were followed for 30 weeks. Patients were classified as either responders or nonresponders based on improvement of depression according to the 17-item Hamilton Depression Rating Scale. Using a longitudinal design, we ascertained mRNA expression at baseline, 2, 8, and 30 weeks and compared mRNA expression between responder and nonresponder patients, and matched controls.

RESULTS

We observed a decrease of SLC6A4 mRNA expression in responder patients across a 30-week follow-up, while nonresponder patients exhibited up-regulated SLC6A4 mRNA.

CONCLUSION

Peripheral SLC6A4 mRNA expression could serve as a biomarker for monitoring and follow-up during an MDE and may help to more appropriately select individualized treatments.

Blood Transcriptomic Markers in Patients with Late-Onset Major Depressive Disorder

We investigated transcriptomic markers of late-onset major depressive disorder (LOD; onset age of first depressive episode ≥ 50 years) from the genes expressed in blood cells and identified state-dependent transcriptomic markers in these patients. We assessed the genes expressed in blood cells by microarray and found that the expression levels of 3,066 probes were state-dependently changed in the blood cells of patients with LOD. To select potential candidates from those probes, we assessed the genes expressed in the blood of an animal model of depression, ovariectomized female mice exposed to chronic ultra-mild stress, by microarray and cross-matched the differentially expressed genes between the patients and the model mice. We identified 14 differentially expressed genes that were similarly changed in both patients and the model mice. By assessing statistical significance using real-time quantitative PCR (RT-qPCR), the following 4 genes were selected as candidates: cell death-inducing DFFA-like effector c (CIDEC), ribonuclease 1 (RNASE1), solute carrier family 36 member-1 (SLC36A1), and serine/threonine/tyrosine interacting-like 1 (STYXL1). The discriminating ability of these 4 candidate genes was evaluated in an independent cohort that was validated. Among them, CIDEC showed the greatest discriminant validity (sensitivity 91.3% and specificity 87.5%). Thus, these 4 biomarkers should be helpful for properly diagnosing LOD.

Neuro-Epigenetic Indications of Acute Stress Response in Humans: The Case of MicroRNA-29c

Stress research has progressively become more integrative in nature, seeking to unfold crucial relations between the different phenotypic levels of stress manifestations. This study sought to unravel stress-induced variations in expression of human microRNAs sampled in peripheral blood mononuclear cells and further assess their relationship with neuronal and psychological indices. We obtained blood samples from 49 healthy male participants before and three hours after performing a social stress task, while undergoing functional magnetic resonance imaging (fMRI). A seed-based functional connectivity (FC) analysis was conducted for the ventro-medial prefrontal cortex (vmPFC), a key area of stress regulation. Out of hundreds of microRNAs, a specific increase was identified in microRNA-29c (miR-29c) expression, corresponding with both the experience of sustained stress via self-reports, and alterations in vmPFC functional connectivity. Explicitly, miR-29c expression levels corresponded with both increased connectivity of the vmPFC with the anterior insula (aIns), and decreased connectivity of the vmPFC with the left dorso-lateral prefrontal cortex (dlPFC). Our findings further revealed that miR-29c mediates an indirect path linking enhanced vmPFC-aIns connectivity during stress with subsequent experiences of sustained stress. The correlative patterns of miR-29c expression and vmPFC FC, along with the mediating effects on subjective stress sustainment and the presumed localization of miR-29c in astrocytes, together point to an intriguing assumption; miR-29c may serve as a biomarker in the blood for stress-induced functional neural alterations reflecting regulatory processes. Such a multi-level model may hold the key for future personalized intervention in stress psychopathology.

Blood-based gene expression signatures of medication-free outpatients with major depressive disorder: integrative genome-wide and candidate gene analyses

Several microarray-based studies have investigated gene expression profiles in major depressive disorder (MDD), yet with highly variable findings. We examined blood-based genome-wide expression signatures of MDD, focusing on molecular pathways and networks underlying differentially expressed genes (DEGs) and behaviours of hypothesis-driven, evidence-based candidate genes for depression. Agilent human whole-genome arrays were used to measure gene expression in 14 medication-free outpatients with MDD who were at least moderately ill and 14 healthy controls matched pairwise for age and sex. After filtering, we compared expression of entire probes between patients and controls and identified DEGs. The DEGs were evaluated by pathway and network analyses. For the candidate gene analysis, we utilized 169 previously prioritized genes and examined their case-control separation efficiency and correlational co-expression network in patients relative to controls. The 317 screened DEGs mapped to a significantly over-represented pathway, the "synaptic transmission" pathway. The protein-protein interaction network was also significantly enriched, in which a number of key molecules for depression were included. The co-expression network of candidate genes was markedly disrupted in patients. This study provided evidence for an altered molecular network along with several key molecules in MDD and confirmed that the candidate genes are worthwhile targets for depression research.

GC-MS based metabolomics identification of possible novel biomarkers for schizophrenia in peripheral blood mononuclear cells

Schizophrenia is a debilitating mental disorder. Currently, the lack of disease biomarkers to support objective laboratory tests constitutes a bottleneck in the clinical diagnosis of schizophrenia. Here, a gas chromatography-mass spectrometry (GC-MS) based metabolomic approach was applied to characterize the metabolic profile of schizophrenia subjects (n = 69) and healthy controls (n = 85) in peripheral blood mononuclear cells (PBMCs) to identify and validate biomarkers for schizophrenia. Multivariate statistical analysis was used to visualize group discrimination and to identify differentially expressed metabolites in schizophrenia subjects relative to healthy controls. The multivariate statistical analysis demonstrated that the schizophrenia group was significantly distinguishable from the control group. In total, 18 metabolites responsible for the discrimination between the two groups were identified. These differential metabolites were mainly involved in energy metabolism, oxidative stress and neurotransmitter metabolism. A simplified panel of PBMC metabolites consisting of pyroglutamic acid, sorbitol and tocopherol-α was identified as an effective diagnostic tool, yielding an area under the receiver operating characteristic curve (AUC) of 0.82 in the training samples (45 schizophrenia subjects and 50 healthy controls) and 0.71 in the test samples (24 schizophrenic patients and 35 healthy controls). Taken together, these findings help to develop diagnostic tools for schizophrenia.

Severe disturbance of glucose metabolism in peripheral blood mononuclear cells of schizophrenia patients: a targeted metabolomic study

Background

Schizophrenia is a widespread and debilitating mental disorder. However, the underlying molecular mechanism of schizophrenia remains largely unknown and no objective laboratory tests are available to diagnose this disorder. The aim of the present study was to characterize the alternations of glucose metabolites and identify potential diagnostic biomarkers for schizophrenia.

Methods

Gas chromatography/mass spectrometry based targeted metabolomic method was used to quantify the levels of 13 glucose metabolites in peripheral blood mononuclear cells (PBMCs) derived from healthy controls, schizophrenia and major depression subjects (n = 55 for each group).

Results

The majority (84.6%) of glucose metabolites were significantly disturbed in schizophrenia subjects, while only two (15.4%) glucose metabolites were differently expressed in depression subjects relative to healthy controls in both training set (n = 35/group) and test set (n = 20/group). Antipsychotics had only a subtle effect on glucose metabolism pathway. Moreover, ribose 5-phosphate in PBMCs showed a high diagnostic performance for first-episode drug-naïve schizophrenia subjects.

Conclusion

These findings suggested disturbance of glucose metabolism may be implicated in onset of schizophrenia and could aid in development of diagnostic tool for this disorder.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0540-y) contains supplementary material, which is available to authorized users.

Postpartum depression: A systematic review of the genetics involved

Postpartum depression is one of the most prevalent psychopathologies. Its prevalence is estimated to be between 10% and 15%. Despite its multifactorial etiology, it is known that genetics play an important role in the genesis of this disorder. This paper reviews epidemiological evidence supporting the role of genetics in postpartum depression (PPD). The main objectives of this review are to determine which genes and polymorphisms are associated with PPD and discuss how this association may occur. In addition, this paper explores whether these genes are somehow related to or even the same as those linked to Major Depression (MD). To identify gaps in the current knowledge that require investigation, a systematic review was conducted in the electronic databases PubMed, LILACS and SciELO using the index terms “postpartum depression” and “genetics”. Literature searches for articles in peer-reviewed journals were made until April 2014. PPD was indexed 56 times with genetics. The inclusion criteria were articles in Portuguese, Spanish or English that were available by institutional means or sent by authors upon request; this search resulted in 20 papers. Genes and polymorphisms traditionally related to MD, which are those involved in the serotonin, catecholamine, brain-derived neurotrophic factor and tryptophan metabolism, have been the most studied, and some have been related to PPD. The results are conflicting and some depend on epigenetics, which makes the data incipient. Further studies are required to determine the genes that are involved in PPD and establish the nature of the relationship between these genes and PPD.

The Influence of genetic factors on peripartum depression: A systematic review

BACKGROUND

This systematic review aimed to explore the potential influence of genetic factors on the symptoms of peripartum depression and to critically analyze the methodologies employed by the examined studies.

METHODS

A systematic review of the literature indexed prior to July 2014 identified 200 articles. After applying the inclusion and exclusion criteria, 39 papers were included.

RESULTS

The papers predominantly featured a molecular genetic approach (n=35), and the majority examined polymorphisms (n=27). Most studies used samples of Caucasians living in high income countries. The results suggest that the influence of genetic factors become more consistent when methodological variations among the studies are considered. Environmental stressors are also important variables that influence the relationship between genetic factors and peripartum depressive states. In addition, differences in the influence of genetic factors were observed depending upon the precise time point during pregnancy or the postpartum period that was examined in the studies. The late stages of pregnancy and the early postpartum period were times of greater genetic vulnerability.

LIMITATIONS

This study was limited by the small number of papers reviewed and by the lack of information regarding whether the effects of genetics on peripartum depression are specific to certain ethnicities and/or stressors.

CONCLUSIONS

Genetic studies of perinatal depression reinforce a pathophysiological role of the hormonal changes inherent in the childbirth period. However, the distinction between depressive episodes that begin during pregnancy from those that begin during the postpartum period can still be useful to improve our understanding of the physiopathology of depressive disorders.

The role of reproductive hormones in postpartum depression

Despite decades of research aimed at identifying the causes of postpartum depression (PPD), PPD remains common, and the causes are poorly understood. Many have attributed the onset of PPD to the rapid perinatal change in reproductive hormones. Although a number of human and nonhuman animal studies support the role of reproductive hormones in PPD, several studies have failed to detect an association between hormone concentrations and PPD. The purpose of this review is to examine the hypothesis that fluctuations in reproductive hormone levels during pregnancy and the postpartum period trigger PPD in susceptible women. We discuss and integrate the literature on animal models of PPD and human studies of reproductive hormones and PPD. We also discuss alternative biological models of PPD to demonstrate the potential for multiple PPD phenotypes and to describe the complex interplay of changing reproductive hormones and alterations in thyroid function, immune function, hypothalamic-pituitary-adrenal (HPA) axis function, lactogenic hormones, and genetic expression that may contribute to affective dysfunction. There are 3 primary lines of inquiry that have addressed the role of reproductive hormones in PPD: nonhuman animal studies, correlational studies of postpartum hormone levels and mood symptoms, and hormone manipulation studies. Reproductive hormones influence virtually every biological system implicated in PPD, and a subgroup of women seem to be particularly sensitive to the effects of perinatal changes in hormone levels. We propose that these women constitute a "hormone-sensitive" PPD phenotype, which should be studied independent of other PPD phenotypes to identify underlying pathophysiology and develop novel treatment targets.

Clinical characteristics of inflammation-associated depression: Monocyte gene expression is age-related in major depressive disorder

Increased inflammatory activation might only be present in a subgroup of depressed individuals in which immune processes are especially relevant to disease development. We aimed to analyze demographic, depression, and trauma characteristics of major depressive disorder (MDD) patients with regard to inflammatory monocyte gene expression. Fifty-six naturalistically treated MDD patients (32 ± 12 years) and 57 healthy controls (HC; 31 ± 11 years) were analyzed by the Inventory of Depressive Symptomatology (IDS) and by the Childhood Trauma Questionnaire (CTQ). We determined the expression of 38 inflammatory and immune activation genes including the glucocorticoid receptor (GR)α and GRβ genes in purified CD14(+) monocytes using quantitative-polymerase chain reaction (RT-qPCR). Monocyte gene expression was age-dependent, particularly in MDD patients. Increased monocyte gene expression and decreased GRα/β ratio were only present in MDD patients aged ⩾ 28 years. Post hoc analyses of monocyte immune activation in patients <28 years showed two subgroups: a subgroup with a severe course of depression (recurrent type, onset <15 years) - additionally characterized by panic/arousal symptoms and childhood trauma - that had a monocyte gene expression similar to HC, and a second subgroup with a milder course of the disorder (73% first episode depression, onset ⩾15 years) - additionally characterized by the absence of panic symptoms - that exhibited a strongly reduced inflammatory monocyte activation compared to HC. In conclusion, monocyte immune activation was not uniformly raised in MDD patients but was increased only in patients of 28 years and older.

Biological and psychosocial predictors of postpartum depression: systematic review and call for integration

Postpartum depression (PPD) adversely affects the health and well being of many new mothers, their infants, and their families. A comprehensive understanding of biopsychosocial precursors to PPD is needed to solidify the current evidence base for best practices in translation. We conducted a systematic review of research published from 2000 through 2013 on biological and psychosocial factors associated with PPD and postpartum depressive symptoms. Two hundred fourteen publications based on 199 investigations of 151,651 women in the first postpartum year met inclusion criteria. The biological and psychosocial literatures are largely distinct, and few studies provide integrative analyses. The strongest PPD risk predictors among biological processes are hypothalamic-pituitary-adrenal dysregulation, inflammatory processes, and genetic vulnerabilities. Among psychosocial factors, the strongest predictors are severe life events, some forms of chronic strain, relationship quality, and support from partner and mother. Fully integrated biopsychosocial investigations with large samples are needed to advance our knowledge of PPD etiology.

In search of neural endophenotypes of postpartum psychopathology and disrupted maternal caregiving

This is a selective review that provides the context for the study of perinatal affective disorder mechanisms and outlines directions for future research. We integrate existing literature along neural networks of interest for affective disorders and maternal caregiving: (i) the salience/fear network; (ii) the executive network; (iii) the reward/social attachment network; and (iv) the default mode network. Extant salience/fear network research reveals disparate responses and corticolimbic coupling to various stimuli based upon a predominantly depressive versus anxious (post-traumatic stress disorder) clinical phenotype. Executive network and default mode connectivity abnormalities have been described in postpartum depression (PPD), although studies are very limited in these domains. Reward/social attachment studies confirm a robust ventral striatal response to infant stimuli, including cry and happy infant faces, which is diminished in depressed, insecurely attached and substance-using mothers. The adverse parenting experiences received and the attachment insecurity of current mothers are factors that are associated with a diminution in infant stimulus-related neural activity similar to that in PPD, and raise the need for additional studies that integrate mood and attachment concepts in larger study samples. Several studies examining functional connectivity in resting state and emotional activation functional magnetic resonance imaging paradigms have revealed attenuated corticolimbic connectivity, which remains an important outcome that requires dissection with increasing precision to better define neural treatment targets. Methodological progress is expected in the coming years in terms of refining clinical phenotypes of interest and experimental paradigms, as well as enlarging samples to facilitate the examination of multiple constructs. Functional imaging promises to determine neural mechanisms underlying maternal psychopathology and impaired caregiving, such that earlier and more precise detection of abnormalities will be possible. Ultimately, the discovery of such mechanisms will promote the refinement of treatment approaches toward maternal affective disturbance, parenting behaviours and the augmentation of parenting resiliency.

Blood transcriptomic biomarkers in adult primary care patients with major depressive disorder undergoing cognitive behavioral therapy

An objective, laboratory-based diagnostic tool could increase the diagnostic accuracy of major depressive disorders (MDDs), identify factors that characterize patients and promote individualized therapy. The goal of this study was to assess a blood-based biomarker panel, which showed promise in adolescents with MDD, in adult primary care patients with MDD and age-, gender- and race-matched nondepressed (ND) controls. Patients with MDD received cognitive behavioral therapy (CBT) and clinical assessment using self-reported depression with the Patient Health Questionnaire-9 (PHQ-9). The measures, including blood RNA collection, were obtained before and after 18 weeks of CBT. Blood transcript levels of nine markers of ADCY3, DGKA, FAM46A, IGSF4A/CADM1, KIAA1539, MARCKS, PSME1, RAPH1 and TLR7, differed significantly between participants with MDD (N=32) and ND controls (N=32) at baseline (q< 0.05). Abundance of the DGKA, KIAA1539 and RAPH1 transcripts remained significantly different between subjects with MDD and ND controls even after post-CBT remission (defined as PHQ-9 <5). The ROC area under the curve for these transcripts demonstrated high discriminative ability between MDD and ND participants, regardless of their current clinical status. Before CBT, significant co-expression network of specific transcripts existed in MDD subjects who subsequently remitted in response to CBT, but not in those who remained depressed. Thus, blood levels of different transcript panels may identify the depressed from the nondepressed among primary care patients, during a depressive episode or in remission, or follow and predict response to CBT in depressed individuals.

Antenatal prediction of postpartum depression with blood DNA methylation biomarkers

Postpartum depression (PPD) affects ∼10-18% of women in the general population and results in serious consequences to both the mother and offspring. We hypothesized that predisposition to PPD risk is due to an altered sensitivity to estrogen-mediated epigenetic changes that act in a cell autonomous manner detectable in the blood. We investigated estrogen-mediated epigenetic reprogramming events in the hippocampus and risk to PPD using a cross-species translational design. DNA methylation profiles were generated using methylation microarrays in a prospective sample of the blood from the antenatal period of pregnant mood disorder patients who would and would not develop depression postpartum. These profiles were cross-referenced with syntenic locations exhibiting hippocampal DNA methylation changes in the mouse responsive to long-term treatment with 17β-estradiol (E2). DNA methylation associated with PPD risk correlated significantly with E2-induced DNA methylation change, suggesting an enhanced sensitivity to estrogen-based DNA methylation reprogramming exists in those at risk for PPD. Using the combined mouse and human data, we identified two biomarker loci at the HP1BP3 and TTC9B genes that predicted PPD with an area under the receiver operator characteristic (ROC) curve (area under the curve (AUC)) of 0.87 in antenatally euthymic women and 0.12 in a replication sample of antenatally depressed women. Incorporation of blood count data into the model accounted for the discrepancy and produced an AUC of 0.96 across both prepartum depressed and euthymic women. Pathway analyses demonstrated that DNA methylation patterns related to hippocampal synaptic plasticity may be of etiological importance to PPD.

Microarray profiling and co-expression network analysis of circulating lncRNAs and mRNAs associated with major depressive disorder

LncRNAs, which represent one of the most highly expressed classes of ncRNAs in the brain, are becoming increasingly interesting with regard to brain functions and disorders. However, changes in the expression of regulatory lncRNAs in Major Depressive Disorder (MDD) have not yet been reported. Using microarrays, we profiled the expression of 34834 lncRNAs and 39224 mRNAs in peripheral blood sampled from MDD patients as well as demographically-matched controls. Among these, we found that 2007 lncRNAs and 1667 mRNAs were differentially expressed, 17 of which were documented as depression-related gene in previous studies. Gene Ontology (GO) and pathway analyses indicated that the biological functions of differentially expressed mRNAs were related to fundamental metabolic processes and neurodevelopment diseases. To investigate the potential regulatory roles of the differentially expressed lncRNAs on the mRNAs, we also constructed co-expression networks composed of the lncRNAs and mRNAs, which shows significant correlated patterns of expression. In the MDD-derived network, there were a greater number of nodes and connections than that in the control-derived network. The lncRNAs located at chr10:874695-874794, chr10:75873456-75873642, and chr3:47048304-47048512 may be important factors regulating the expression of mRNAs as they have previously been reported associations with MDD. This study is the first to explore genome-wide lncRNA expression and co-expression with mRNA patterns in MDD using microarray technology. We identified circulating lncRNAs that are aberrantly expressed in MDD and the results suggest that lncRNAs may contribute to the molecular pathogenesis of MDD.

Are there meaningful biomarkers of treatment response for depression?

During the past decades, the prevalence of affective disorders has been on the rise globally, with only one out of three patients achieving remission in acute treatment with antidepressants. The identification of physiological markers that predict treatment course proves useful in increasing therapeutic success. On the basis of well-documented, recent findings in depression research, we highlight and discuss the most promising biomarkers for antidepressant therapy response. These include genetic variants and gene expression profiles, proteomic and metabolomic markers, neuroendocrine function tests, electrophysiology and imaging techniques. Ultimately, this review proposes an integrative use of biomarkers for antidepressant treatment outcome.

Inflammatory activation is associated with a reduced glucocorticoid receptor alpha/beta expression ratio in monocytes of inpatients with melancholic major depressive disorder

In this study, we used new technology to investigate whether a coherent pattern of enhanced expression of inflammatory and other immune activation genes in circulating monocytes is found in patients with major depression. Since a high inflammatory state of monocytes might be related to glucocorticoid resistance, we also included the genes for the two isoforms of the glucocorticoid receptor. For this study, we aimed at finding a similar coherent pattern of inflammatory and immune activation genes in monocytes of patients with MDD and recruited 47 medication-free melancholic MDD inpatients and 42 healthy controls. A quantitative-polymerase chain reaction (Q-PCR) monocyte gene expression analysis was performed using a panel of inflammatory-related genes previously identified as abnormally regulated in mood disorder patients. Selected serum cytokines/chemokines were assessed using a cytometric bead array. Depressive symptoms were analysed using Hamilton depression scores (HAMD). Thirty-four of the 47 monocyte inflammatory-related genes were significantly upregulated and 2 were significantly downregulated as compared to controls, the latter including the gene for the active GRα in particular in those with a high HAMD score. The reduced GRα expression correlated strongly to the upregulation of the inflammatory genes in monocytes. Serum levels of IL6, IL8, CCL2 and VEGF were significantly increased in patients compared to controls. Our data show the deregulation of two interrelated homoeostatic systems, that is, the immune system and the glucocorticoid system, co-occurring in major depression.

Gene expression: biomarker of antidepressant therapy?

While antidepressant therapy is an essential treatment of major depression, a substantial group of treated patients do not respond to therapy, or suffer from severe side effects. Moreover, the time of onset of the clinical improvement is often delayed. Antidepressants as currently available usually enhance serotonergic, noradrenergic and dopaminergic neurotransmission and may contribute to the inadequate remission rates for major depression. Therefore biomarkers enabling the identification of subgroups of patients and also finding unprecedented targets would provide the basis for personalized medication and thus improve treatment efficacy and reduce side effects. Several pharmacogenetic studies on antidepressant treatment response using single nucleotide polymorphism (SNPs) mapping have been performed but provided only modest findings. Therefore the analysis of gene expression to integrate genomic activity and environmental effects promises a new approach to cope with the complexity of factors influencing antidepressant treatment. Here gene expression studies focusing on candidate genes and genome-wide approaches using RNA derived from peripheral blood cells are reviewed. The most promising findings exist for hypothalamic-pituitary-adrenal (HPA) axis, inflammation and neuroplasticity related genes. However, straightforward translation into tailored treatment is still unlikely. Contradictory results limit the clinical use of the findings. Future studies are necessary, which could include functional analysis and consider gene-environment interactions.

Coding and noncoding gene expression biomarkers in mood disorders and schizophrenia

Mood disorders and schizophrenia are common and complex disorders with consistent evidence of genetic and environmental influences on predisposition. It is generally believed that the consequences of disease, gene expression, and allelic heterogeneity may be partly the explanation for the variability observed in treatment response. Correspondingly, while effective treatments are available for some patients, approximately half of the patients fail to respond to current neuropsychiatric treatments. A number of peripheral gene expression studies have been conducted to understand these brain-based disorders and mechanisms of treatment response with the aim of identifying suitable biomarkers and perhaps subgroups of patients based upon molecular fingerprint. In this review, we summarize the results from blood-derived gene expression studies implemented with the aim of discovering biomarkers for treatment response and classification of disorders. We include data from a biomarker study conducted in first-episode subjects with schizophrenia, where the results provide insight into possible individual biological differences that predict antipsychotic response. It is concluded that, while peripheral studies of expression are generating valuable results in pathways involving immune regulation and response, larger studies are required which hopefully will lead to robust biomarkers for treatment response and perhaps underlying variations relevant to these complex disorders.

Relaxation response induces temporal transcriptome changes in energy metabolism, insulin secretion and inflammatory pathways

The relaxation response (RR) is the counterpart of the stress response. Millennia-old practices evoking the RR include meditation, yoga and repetitive prayer. Although RR elicitation is an effective therapeutic intervention that counteracts the adverse clinical effects of stress in disorders including hypertension, anxiety, insomnia and aging, the underlying molecular mechanisms that explain these clinical benefits remain undetermined. To assess rapid time-dependent (temporal) genomic changes during one session of RR practice among healthy practitioners with years of RR practice and also in novices before and after 8 weeks of RR training, we measured the transcriptome in peripheral blood prior to, immediately after, and 15 minutes after listening to an RR-eliciting or a health education CD. Both short-term and long-term practitioners evoked significant temporal gene expression changes with greater significance in the latter as compared to novices. RR practice enhanced expression of genes associated with energy metabolism, mitochondrial function, insulin secretion and telomere maintenance, and reduced expression of genes linked to inflammatory response and stress-related pathways. Interactive network analyses of RR-affected pathways identified mitochondrial ATP synthase and insulin (INS) as top upregulated critical molecules (focus hubs) and NF-κB pathway genes as top downregulated focus hubs. Our results for the first time indicate that RR elicitation, particularly after long-term practice, may evoke its downstream health benefits by improving mitochondrial energy production and utilization and thus promoting mitochondrial resiliency through upregulation of ATPase and insulin function. Mitochondrial resiliency might also be promoted by RR-induced downregulation of NF-κB-associated upstream and downstream targets that mitigates stress.

Postpartum depression: current status and future directions

Postpartum depression (PPD) is a common and serious mental health problem that is associated with maternal suffering and numerous negative consequences for offspring. The first six months after delivery may represent a high-risk time for depression. Estimates of prevalence range from 13% to 19%. Risk factors mirror those typically found with major depression, with the exception of postpartum-specific factors such as sensitivity to hormone changes. Controlled trials of psychological interventions have validated a variety of individual and group interventions. Medication often leads to depression improvement, but in controlled trials there are often no significant differences in outcomes between patients in the medication condition and those in placebo or active control conditions. Reviews converge on recommendations for particular antidepressant medications for use while breastfeeding. Prevention of PPD appears to be feasible and effective. Finally, there is a growing movement to integrate mental health screening into routine primary care for pregnant and postpartum women and to follow up this screening with treatment or referral and with follow-up care. Research and clinical recommendations are made throughout this review.

Depression pathogenesis and treatment: what can we learn from blood mRNA expression?

Alterations in several biological systems, including the neuroendocrine and immune systems, have been consistently demonstrated in patients with major depressive disorder. These alterations have been predominantly studied using easily accessible systems such as blood and saliva. In recent years there has been an increasing body of evidence supporting the use of peripheral blood gene expression to investigate the pathogenesis of depression, and to identify relevant biomarkers. In this paper we review the current literature on gene expression alterations in depression, focusing in particular on three important and interlinked biological domains: inflammation, glucocorticoid receptor functionality and neuroplasticity. We also briefly review the few existing transcriptomics studies. Our review summarizes data showing that patients with major depressive disorder exhibit an altered pattern of expression in several genes belonging to these three biological domains when compared with healthy controls. In particular, we show evidence for a pattern of 'state-related' gene expression changes that are normalized either by remission or by antidepressant treatment. Taken together, these findings highlight the use of peripheral blood gene expression as a clinically relevant biomarker approach.

Deep brain stimulation induces rapidly reversible transcript changes in Parkinson's leucocytes

Subthalamic deep brain stimulation (DBS) reversibly modulates Parkinson's disease (PD) motor symptoms, providing an unusual opportunity to compare leucocyte transcripts in the same individuals before and after neurosurgery and 1 hr after stimulus cessation (ON- and OFF-stimulus). Here, we report DBS-induced reversibility and OFF-stimulus restoration in 12 of 16 molecular functions and 3 of 4 biological processes shown in exon microarrays to be differentially expressed between PD patients and controls, post-DBS from pre-DBS and OFF from ON states. Intriguingly, 6 of 18 inflammation and immune-related functions exhibited reversibility, and the extent of stimulus-induced changes correlated with the neurological DBS efficacy, suggesting mechanistic implications. A minimal list of 29 transcripts that changed in all three comparisons between states discriminated pre-surgery and OFF states from post-surgery and controls. Six of these transcripts were found to be able to distinguish between PD patients and both healthy controls and patients with other neurological diseases in a previously published whole blood 3’ array data study of early PD patients. Our findings support the future use of this approach for identifying targets for therapeutic intervention and assessing the efficacy of current and new treatments in this and other neurological diseases.