Gene expression profiling in peripheral blood leukocytes as a new approach for assessment of human stress response

The immunomodulatory effects of social isolation in mice are linked to temperature control

Living in isolation is considered an emerging societal problem that negatively affects the physical wellbeing of its sufferers in ways that we are just starting to appreciate. This study investigates the immunomodulatory effects of social isolation in mice, utilising a two-week program of sole cage occupancy followed by the testing of immune-inflammatory resilience to bacterial sepsis. Our results revealed that mice housed in social isolation showed an increased ability to clear bacterial infection compared to control socially housed animals. These effects were associated with specific changes in whole blood gene expression profile and an increased production of classical pro-inflammatory cytokines. Interestingly, equipping socially isolated mice with artificial nests as a substitute for their natural huddling behaviour reversed the increased resistance to bacterial sepsis. Together these results suggest that the control of body temperature through social housing and huddling behaviour are important factors in the regulation of the host immune response to infection in mice and might provide another example of the many ways by which living conditions influence immunity.

The Systematic Analysis of Exercise Mechanism in Human Diseases

Background

As a part of a healthy lifestyle, exercise has been proven to be beneficial for the treatment of diseases and the prognosis of patients. Based on this, our research focuses on the impact of exercise on human health.

Methods

To study and analyze the samples in the GSE18966 gene expression profile, we first performed an analysis on the differential expressed genes (DEGs) through GEO2R, and then the DEGs enrichment in Gene Ontology functions and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways through the Database for Annotation, Visualization and Integrated Discovery database was conducted. Then, we delved into the gene set enrichment in KEGG through gene set enrichment analysis. After that, we achieved the construction of the protein-protein interaction (PPI) network of DEGs based on the Search Tool for the Retrieval of Interacting Genes online database, and the hub genes were screened and identified.

Results

We identified 433 upregulated DEGs and 186 downregulated DEGs from the samples before and after exercise in GSE18966. Through analysis, it was found that these DEGs-enriched pathways, such as the VEGF signaling pathway, the Wnt signaling pathway, and the insulin signaling pathway, were all involved in the regulation of various diseases. Then, GSEA analysis revealed that glycosaminoglycan biosynthesis chondroitin sulfate, type II diabetes mellitus, and basal cell carcinoma were related with exercise samples. The effects of these pathways on various diseases could be improved through exercise. Finally, 3 upregulated hub genes (VEGFA, POMC, and NRAS) and 3 downregulated hub genes (HRAS, NCOR1, and CAV1) were identified through the PPI network.

Conclusions

The bioinformatic analysis of samples before and after exercise provides key pathways and genes related to exercise to regulate various diseases, which confirms that exercise has an important influence on the treatment of many diseases.

Stress Hormone Cortisol Enhances Bcl2 Like-12 Expression to Inhibit p53 in Hepatocellular Carcinoma Cells

BACKGROUND AND AIMS

The pathogenesis of hepatocellular carcinoma (HC) is unclear. It is suggested that psychological stress associates with the pathogenesis of liver cancer. Bcl2-like protein 12 (Bcl2L12) suppresses p53 protein. This study tests a hypothesis that the major stress hormone, cortisol, inhibits the expression of p53 in HC cells (HCC) via up regulating the expression of Bcl2L12.

METHODS

Peripheral blood samples were collected from patients with HC to be analyzed for the levels of cortisol. HCC were cultured to assess the role of cortisol in the regulation of the expression of Bcl2L12 and p53 in HCC.

RESULTS

We observed that the serum cortisol levels were higher in HC patients. Expression of Bcl2L12 in HCC was correlated with serum cortisol. Cortisol enhanced the Bcl2L12 expression in HCC. Bcl2L12 binding to the TP53 promoter was correlated with p53 expression in HCC. Cortisol increased the Bcl2L12 expression in HCC to inhibit p53 expression.

CONCLUSIONS

Stress hormone cortisol suppresses p53 in HCC via enhancing Bcl2L12 expression in HCC. The results suggest that cortisol may be a therapeutic target for the treatment of HC.

The effects of administration of the Lactobacillus gasseri strain CP2305 on quality of life, clinical symptoms and changes in gene expression in patients with irritable bowel syndrome

AIMS

To clarify the effects of Lactobacillus gasseri CP2305 (CP2305) on quality of life and clinical symptoms and its functional mechanisms in patients with irritable bowel syndrome (IBS).

METHODS AND RESULTS

After the patients were administered CP2305 daily for 4 weeks, the IBS-severity index score was significantly improved compared with that of the placebo group, and this improvement was accompanied by a reduction in health-related worry and changes in intestinal microbiota. The gene expression profiling of the peripheral blood leucocytes showed that CP2305 treatment significantly up-regulated genes related to eukaryotic initiation factor 2 (EIF2) signalling. Eighty-two genes were down-regulated in IBS patients compared with healthy controls. The expression of 23 of these genes exhibited a CP2305-dependent increase associated with an improvement in IBS severity. The majority of the restored genes were related to EIF2 signalling.

CONCLUSIONS

CP2305 administration is a potential candidate therapeutic option for patients with IBS.

SIGNIFICANCE AND IMPACT OF THE STUDY

Although probiotics have been proposed to benefit IBS patients, objective clinical evidence and elucidation of the functional mechanism remain insufficient. Our study demonstrated that CP2305 administration beneficially influences IBS patients in both subjective and objective evaluations, and gene expression profiling provided insights into the functional mechanism.

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.

Biomarkers of treatment toxicity in combined-modality cancer therapies with radiation and systemic drugs: study design, multiplex methods, molecular networks

Organ toxicity in cancer therapy is likely caused by an underlying disposition for given pathophysiological mechanisms in the individual patient. Mechanistic data on treatment toxicity at the patient level are scarce; hence, probabilistic and translational linkages among different layers of data information, all the way from cellular targets of the therapeutic exposure to tissues and ultimately the patient’s organ systems, are required. Throughout all of these layers, untoward treatment effects may be viewed as perturbations that propagate within a hierarchically structured network from one functional level to the next, at each level causing disturbances that reach a critical threshold, which ultimately are manifested as clinical adverse reactions. Advances in bioinformatics permit compilation of information across the various levels of data organization, presumably enabling integrated systems biology-based prediction of treatment safety. In view of the complexity of biological responses to cancer therapy, this communication reports on a “top-down” strategy, starting with the systematic assessment of adverse effects within a defined therapeutic context and proceeding to transcriptomic and proteomic analysis of relevant patient tissue samples and computational exploration of the resulting data, with the ultimate aim of utilizing information from functional connectivity networks in evaluation of patient safety in multimodal cancer therapy.

Transcriptomics to study the effect of a Mediterranean-inspired diet on inflammation in Crohn's disease patients

Background

Inflammation is an essential immune response; however, chronic inflammation results in disease including Crohn's disease. Therefore, reducing the inflammation can yield a significant health benefit, and one way to achieve this is through diet. We developed a Mediterranean-inspired anti-inflammatory diet and used this diet in a 6-week intervention in a Crohn's disease population. We examined changes in inflammation and also in the gut microbiota. We compared the results of established biomarkers, C-reactive protein and the micronuclei assay, of inflammation with results from a transcriptomic approach.

Results

Data showed that being on our diet for 6 weeks was able to reduce the established biomarkers of inflammation. However, using transcriptomics, we observed significant changes in gene expression. Although no single gene stood out, the cumulative effect of small changes in many genes combined to have a beneficial effect. Data also showed that our diet resulted in a trend of normalising the microbiota.

Conclusions

This study showed that our Mediterranean-inspired diet appeared to benefit the health of people with Crohn's disease. Our participants showed a trend for reduced markers of inflammation and normalising of the microbiota. The significant changes in gene expression after 6 weeks highlighted the increased sensitivity of using transcriptomics when compared to the established biomarkers and open up a new era of dietary intervention studies.

Transcriptome characterization of immune suppression from battlefield-like stress

Transcriptome alterations of leukocytes from soldiers who underwent 8 weeks of Army Ranger training (RASP, Ranger Assessment and Selection Program) were analyzed to evaluate impacts of battlefield-like stress on the immune response. About 1400 transcripts were differentially expressed between pre- and post-RASP leukocytes. Upon functional analysis, immune response was the most enriched biological process, and most of the transcripts associated with the immune response were downregulated. Microbial pattern recognition, chemotaxis, antigen presentation and T-cell activation were among the most downregulated immune processes. Transcription factors predicted to be stress-inhibited (IRF7, RELA, NFκB1, CREB1, IRF1 and HMGB) regulated genes involved in inflammation, maturation of dendritic cells and glucocorticoid receptor signaling. Many altered transcripts were predicted to be targets of stress-regulated microRNAs. Post-RASP leukocytes exposed ex vivo to Staphylococcal enterotoxin B showed a markedly impaired immune response to this superantigen compared with pre-RASP leukocytes, consistent with the suppression of the immune response revealed by transcriptome analyses. Our results suggest that suppression of antigen presentation and lymphocyte activation pathways, in the setting of normal blood cell counts, most likely contribute to the poor vaccine response, impaired wound healing and infection susceptibility associated with chronic intense stress.

Gene expression of peripheral blood mononuclear cells as a tool in dietary intervention studies: What do we know so far?

Peripheral blood mononuclear cells (PBMCs) generally refer to monocytes and lymphocytes, representing cells of the innate and adaptive immune systems. PBMCs are a promising target tissue in the field of nutrigenomics because they seem to reflect the effects of dietary modifications at the level of gene expression. In this review, we describe and discuss the scientific literature concerning the use of gene expression at the mRNA level measured from PBMCs in dietary interventions studies conducted in humans. A search of literature was undertaken using PubMed (last assessed November 24, 2011) and 20 articles were selected for discussion. Currently, results from these studies showed that PBMCs seem to reflect liver environment and complement adipose tissue findings in transcriptomics. PBMC gene expression after dietary intervention studies can be used for studying the response of certain genes related to fatty acid and cholesterol metabolism, and to explore the response of dietary interventions in relation to inflammation. However, PBMC transcriptomics from dietary intervention studies have not resulted yet in clear confirmation of candidate genes related to disease risk. Use of microarray technology in larger well-designed dietary intervention studies is still needed for exploring PBMC potential in the field of nutrigenomics.

The antioxidant potential of alprazolam on the redox status of peripheral blood leukocytes in restraint-stressed mice

AIMS

Stress can cause adverse reactions in the body that induce a wide range of biochemical and behavioral changes. Oxidative damage is an established outcome of stress that has been implicated in the pathogenesis of mood and anxiety disorders. Anxiolytic drugs are widely prescribed to treat these conditions; however, no animal study has investigated the effect of benzodiazepines on the levels of intracellular reactive oxygen species (ROS) in the peripheral blood leukocytes of stressed mice.

MAIN METHODS

Mice were immobilized for a period of 6h. Alprazolam (0.1-0.8 mg/kg of body weight) was administered 30 min before subjecting the animals to acute stress. The level of intracellular ROS in lymphocytes, granulocytes, and monocytes in the peripheral blood of stressed mice was investigated by using a 2',7'-dichlorofluorescein diacetate (DCFH-DA) probe.

KEY FINDINGS

Our results show that restraint stress significantly increases the generation of ROS in peripheral defense cells. Treatment with alprazolam partially reverses the adverse effects of stress.

SIGNIFICANCE

Our findings suggest that the therapeutic efficacy of alprazolam may be mediated, at least partially, by the reversal of oxidative damage as demonstrated by the protective enhancement of antioxidant status following a stress-induced decline. Because alprazolam is used for the treatment of anxiety in patients with cancer, neurodegenerative disease, inflammatory bowel diseases, and other diseases, these results may have important clinical implications.

Suppressed monocyte gene expression profile in men versus women with PTSD

There have been several attempts to use gene microarrays from peripheral blood mononuclear cells to identify new biological pathways or targets for therapy in Posttraumatic Stress Disorder (PTSD). The few studies conducted to date have yielded an unclear pattern of findings, perhaps reflecting the use of heterogeneous samples of circulating immune cells for analysis. We used gene microarrays on a homogeneous sample of circulating monocytes to test the hypothesis that chronic PTSD would be associated with elevated inflammatory activity and to identify new pathways dysregulated in the disorder. Forty-nine men (24 PTSD+ and 25 age-matched trauma-exposed PTSD- controls) and 18 women (10 PTSD+ and 8 age-matched PTSD- controls) were recruited. Gene expression microarray analysis was performed on CD14+ monocytes, immune cells that initiate and respond to inflammatory signaling. Male subjects with PTSD had an overall pattern of under-expression of genes on monocytes (47 under-expressed versus 4 over-expressed genes). A rigorous correction for multiple comparisons and verification with qPCR showed that of only 3 genes that were differentially expressed, all were under-expressed. There was no transcriptional evidence of chronic inflammation in male PTSD+ subjects. In contrast, preliminary data from our pilot female PTSD+ subjects showed a relatively balanced pattern of increased and decreased expression of genes and an increase in activity of pathways related to immune activation. The results indicate differential patterns of monocyte gene expression in PTSD, and the preliminary data from our female pilot subjects are suggestive of gender dimorphism in biologic pathways activated in PTSD. Changes in immune cell gene expression may contribute to medical morbidity in PTSD.

Elevating the perspective on human stress genomics

Functional genomics strategies have been slow to penetrate research on human stress and coping, but recent conceptual advances have yielded a raft of new findings relating social and psychological conditions to broad alterations in human gene expression. This article reviews the field of human stress genomics, analyzes some of the conceptual and technical issues that initially hampered its progress, and outlines an abstractionist approach to genomic data analysis that has revealed a surprisingly consistent pattern of human transcriptional responses to diverse types of socio-environmental adversity. This field is now poised for another round of significant advances as research begins to incorporate the effects of DNA polymorphism, target a broader array of healthy and diseased tissues, and identify general teleologic and regulatory themes by pooling results over a growing body of studies analyzing the human transcriptional response to stress.

Reduced peripheral brain-derived neurotrophic factor mRNA levels are normalized by antidepressant treatment

Consistent data coming from biochemical studies have evidenced a brain-derived neurotrophic factor (BDNF) serum reduction in depressed patients compared to controls and a restoration following antidepressant treatment. However, to date, no study has evaluated whether BDNF synthesis in leukocytes could contribute to such modulation. Therefore, in this study, we analysed BDNF mRNA levels in leukocytes from 21 depressed patients prior to and during escitalopram treatment and from 23 control subjects showing that BDNF mRNA levels were decreased in drug-free depressed patients and that 12 wk escitalopram treatment was able to reverse this deficit. Interestingly, changes in BDNF mRNA levels paralleled BDNF serum increase during antidepressant treatment, and were correlated with symptoms improvement. Our results indicate that BDNF serum modulation observed in depressed patients is associated with BDNF synthesis alteration in leukocytes and suggest that these peripheral cells might play an active role in the mechanisms of action of antidepressants.

Chromatin ultrastructural abnormalities in leukocytes, as peripheral markers of bipolar patients

This study investigated the ultrastructural conformation changes of the chromatin in blood leukocytes of bipolar patients, versus normal controls, by using the phosphotungstic acid-hematoxylin (PTAH) block-staining method, modified for electron microscopy, and the immunohistochemical localization of the histone H1, by the immunogold method. These two methods are basically complementary. If histone H1 immunolabeling is used, it shows that the immunogold labeling on chromatin is different in the three phases of the illness, i.e., high in normothymia and low in depression as well as in mania. However, in this particular tissue fixation (4% paraformaldehyde-1% glutaraldehyde in 0,1 M phosphate buffer), the heterochromatin in the nuclei remains identical in the three phases of the illness. On the other hand, the PTAH method shows exactly the area of electron-lucent condensed chromatin, separate from the area of electron-dense, decondensed, chromatin. The present data confirmed that both the clinical state of depression as well as that of mania display activated lymphocytes and neutrophils with their characteristic relaxed de-condensed chromatin. On the contrary, the state of normothymia shows a reversion to the condensed state of the chromatin, as it is observed in the leukocytes of the normal controls. The ultrastructural conformations of the chromatin, revealed by the PTAH method, in combination with the histone H1 immunogold labeling, applied in blood leukocytes, supports the use of these two methods, as screening methods of choice in investigating blood biological markers in mental illness.

Chronic immobilization stress induces anxiety- and depression-like behaviors and decreases transthyretin in the mouse cortex

In this study, we examined the changes in gene expression in the mouse cortex following chronic stress and behavioral tests. Mice were subjected to immobilization stress for 2h per day for 15 consecutive days and the behavior of the mice was examined. The mice in the experimental group were more anxious and depressive than the control mice. The expression of mRNA in the cortex was analyzed by microarray analysis and 63 genes were found to show a greater than twofold change in expression between the control and experimental groups. Transthyretin was further investigated because its expression showed the greatest fold change. Transthyretin mRNA expression decreased in a chronic stress-specific manner, and protein levels were reduced in the cortex but not in the choroid plexus.

An angiotensin-1 converting enzyme polymorphism is associated with allostatic load mediated by C-reactive protein, interleukin-6 and cortisol

Allostatic load (AL) is a theoretical framework that describes the cumulative physiologic effects of adaptation to change or stress throughout the lifespan. AL is operationalized by a composite index of multiple biomarkers. Accordingly, genes, behavior and environment contribute to AL. To determine if individual differences in AL may be influenced by inherent genetic variation, we calculated an allostatic load index (ALI) for 182 Caucasian subjects derived from a population-based study of chronic fatigue syndrome. Nearly 65% of the subjects in this study sample reported fatiguing illness. ALI was calculated based on 11 measures representing metabolic, cardiovascular, inflammatory, hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) activities. Subjects were dichotomized into high (ALI > or = 3) or low (ALI < 3) AL groups, and the association between high AL and 129 polymorphisms in 32 genes related to the HPA axis, neurotransmission, inflammation, cardiovascular and metabolic functions were evaluated. Polymorphisms in angiotensin-1 converting enzyme (ACE), corticotropin-releasing hormone receptor 1 (CRHR1), and serotonin receptors (HTR3A and HTR4) were associated with AL (p=0.0007-0.0486), but only one polymorphism, rs4968591, in ACE remained significant after correction for multiple comparisons. The T allele of ACE rs4968591 was more common in subjects with high AL (67.5%) than in subjects with low AL (49.3%) (p=0.0007), and this effect appeared independent of age, sex, body mass index and fatigue status. Additionally, high interleukin-6 (IL-6; p(trend)=0.04), and C-reactive protein (CRP; p(trend)=0.01) levels, as well as low urinary cortisol levels in females (p=0.03) were associated with the T allele, which may result in allele-specific binding of the transcription factor, E2F1. Our results suggest a role for ACE in the bidirectional communication between the central nervous and immune systems in response to stress. Further studies will be needed (a) to replicate the association between AL and ACE polymorphisms in population studies designed to differentiate the effects of sex, age and racial/ethnic background, (b) to evaluate the effect of allele-specific binding of E2F1 at rs4968591, and (c) to examine the role of ACE in the co-regulation of CRP, IL-6 and cortisol.

Psychobiology of posttraumatic stress disorder in pediatric injury patients: A review of the literature

Research suggests that about a quarter to a third of children with traffic-related injuries develop posttraumatic stress disorder (PTSD). Early symptoms of PTSD have been found to predict poor mental and physical outcome in studies of medically injured children. However, these symptoms are rarely recognized by physicians who provide emergency care for these children. In addition, there is insufficient knowledge about predictors of posttraumatic stress symptoms in this specific pediatric population. Early identification of those children at particular risk is needed to target preventive interventions appropriately. After some introducing remarks on the classification and the nature of posttraumatic stress reactions, current research findings on psychological and biological correlates of PTSD in pediatric injury patients are presented. The particular focus in this paper is on the neurobiological mechanisms that influence psychological responses to extreme stress and the development of PTSD. Continued study of the psychobiology of trauma and PTSD in pediatric injury patients, both in terms of neurobiology and treatment is needed.

Molecular assessment of depression from mRNAs in the peripheral leukocytes

Depression is a disorder not only in the central nervous system (CNS), but also in the systemic neuroendocrine, autonomic nervous, and immune systems. The changes in these systems have been widely studied in depression by using serum proteins because they are easily and repetitively studied before, during, and after treatment. Recently, gene expressions in the peripheral blood leukocytes have been used to assess the depressive changes in the CNS by DNA microarrays and/or real-time polymerase chain reaction (PCR) methods. These studies will give us clues to assess depression because circulating peripheral leukocytes are influenced by systems that underlie depression, and the quantification of mRNAs in them is methodologically precise and easier than that of protein. In this paper, we review the studies on the leukocyte gene expression, including our own, and discuss the limitations and strengths of the current gene expression-based molecular assessment of depression by the leukocyte mRNA expression.

The Application of Microarray Technology to Neuropathology: Cutting Edge Tool With Clinical Diagnostics Potential or Too Much Information?

Microarray technology is a tremendously powerful method for simultaneously monitoring the expression of thousands of species of nucleic acids, usually cellular mRNA, producing a high-resolution representation of the genes encoded or expressed in a cell. As such, microarray technology has great potential for impacting research and clinical approaches to treatment. However, this complex technology has been challenging to apply as a result of difficulties discerning biologic variation from technologic issues, therefore slowing the application of the technology to human diagnostics. Nevertheless, significant advances in microarray technology, improvements that avoid potential pitfalls, and a wider spectrum of application are making this technology easier to apply. Indeed, microarray technology has provided valuable insights into mechanisms involving gene regulation and expression in Alzheimer disease, and it remains a powerful tool to identify biomarkers for disease diagnosis. Ultimately, the most robust markers will enable the application of more specific treatments particular to disease stages or subcategories. Currently, no widely applicable molecular test is available to identify those at risk for developing Alzheimer disease or those who have early markers of pathology but show discernible cognitive impairment. The progression of this technology will lead to earlier detection of the disease through enhanced understanding of disease onset and progression.

Approach to novel functional foods for stress control 2. Microarray assessment of exercise in healthy volunteers

DNA microarray was used to measure stress response by exercise in peripheral blood leukocytes. Aerobic exercise did not alter mRNA pattern or urinary secretion of 8-hydroxy-2'-deoxyguanosine (8-OHdG). Strenuous exercise increased urinary secretion of 8-OHdG and altered mRNA pattern in microarray. These results suggest that moderate exercise, i. e. aerobic exercise, did not show any change in 8-OHdG, an oxidative stress marker, or mRNA expression in the leukocytes, which might reflect whole body neurohormanal changes. In addition, strenuous exercise produced quite different expression pattern from those of psychological stress.