Gene expression analysis in combat veterans with and without post-traumatic stress disorder

A Systematic Review of DNA Methylation and Gene Expression Studies in Posttraumatic Stress Disorder, Posttraumatic Growth, and Resilience

Most people will experience a traumatic event within their lifetime. One commonly recognized response to trauma exposure is posttraumatic stress disorder (PTSD). The biological underpinnings of PTSD, including epigenetic mechanisms of DNA methylation and gene expression, have been studied intensively. However, psychological posttrauma responses vary widely and can include positive outcomes, such as posttraumatic growth (PTG) and, more commonly, resilience. The aim of this systematic review was to summarize the current DNA methylation and gene expression data with respect to three potential posttrauma responses: PTSD, PTG, and resilience. A literature search identified 486 studies, 51 of which were deemed eligible for inclusion (total N = 10,633). All included studies examined PTSD and consistently implicated DNA methylation and gene expression changes in hypothalamic-pituitary-adrenal axis and inflammatory genes. Ten studies acknowledged resilience as a posttrauma response, but only two studies examined epigenetics and gene expression using a scale to measure resilience. Low resilience was associated with gene expression patterns in immune and dopamine genes, and high resilience was associated with a blunted inflammatory response. No studies examined epigenetic or gene expression changes associated with PTG. These findings highlight a focus on pathogenic research, which has failed to adequately acknowledge and measure positive posttrauma outcomes of PTG and resilience. Future research should examine DNA methylation and gene expression changes associated with PTG and resilience in addition to PTSD in order to gain a more comprehensive picture of an individual's well-being following exposure to trauma.

Do Noncoding RNAs Mediate the Efficacy of Energy Psychology?

BACKGROUND

There are over 100 published studies of a therapy called Emotional Freedom Techniques (EFT). This popular form of energy psychology combines elements of established methods like cognitive therapy with acupressure. Our group reported the first evidence of its mechanisms of action at the molecular level, showing that it can influence levels of the stress hormone cortisol.

OBJECTIVES

Given recent advances in molecular genomics that have identified noncoding ribonucleic acid (RNA) molecules as important regulators of gene expression, the aim of this study is to explore the possibility that microRNAs play a role in mediating the effects of EFT.

METHODS

We measured microRNA levels in stored blood samples from our previous study in which veterans were randomized into an EFT group receiving EFT and treatment as usual throughout a 10-week intervention period, and a control group receiving only treatment as usual during the intervention period and then receiving EFT. A broad panel of 800 microRNAs was probed using a multiplexed, direct hybridization, and detection system.

RESULTS

All of the microRNA targets were expressed at low levels and most were below thresholds established by negative control probes. Baseline variability was determined using samples collected from the control group at the start and end of the intervention period, and used to filter out targets that were too noisy under control conditions to be able to distinguish a response to treatment. Analysis of the remaining viable targets found a general trend of reduced expression following EFT, compared to expression levels in samples from the control group during the intervention period. The most notable decreases in expression levels were found for 2 microRNAs: let-7b and let-7c, although no significance was found after adjusting for multiple comparisons.

CONCLUSIONS

These preliminary data support the feasibility of measuring microRNA expression level changes that correlate with effective EFT therapy.

Expression and methylation in posttraumatic stress disorder and resilience; evidence of a role for odorant receptors

Post-traumatic stress disorder (PTSD) is a common and potentially disabling disorder that develops in 1/5 to 1/3 of people exposed to severe trauma. Twin studies indicate that genetic factors account for at least one third of the variance in the risk for developing PTSD, however, the specific role for genetic factors in the pathogenesis of PTSD is not well understood. We studied genome-wide gene expression and DNA methylation profiles in 12 participants with PTSD and 12 participants who were resilient to similar severity trauma exposure. Close to 4000 genes were differentially expressed with adjusted p<0.05, fold-change >2, with all but 3 upregulated with PTSD. Eight odorant/olfactory receptor related genes were up-regulated with PTSD as well as genes related to immune activation, the Gamma-Aminobutyric Acid A (GABAA) receptor, and vitamin D synthesis. No differences with adjusted significance for DNA methylation were found. We conclude that increased gene expression may play an important role in PTSD and this expression may not be a consequence of DNA methylation. The role of odorant receptor expression warrants independent replication.

Epigenetic Effects of PTSD Remediation in Veterans Using Clinical Emotional Freedom Techniques: A Randomized Controlled Pilot Study

PURPOSE

To assess the feasibility of measuring changes in gene expression associated with post-traumatic stress disorder (PTSD) treatment using emotional freedom techniques (EFT).

DESIGN

Participants were randomized into an EFT group receiving EFT and treatment as usual (TAU) throughout a 10-week intervention period and a group receiving only TAU during the intervention period and then receiving EFT.

SETTING

A community clinic and a research institute in California.

PARTICIPANTS

Sixteen veterans with clinical levels of PTSD symptoms.

INTERVENTION

Ten hour-long sessions of EFT.

MEASURES

Messenger RNA levels for a focused panel of 93 genes related to PTSD. The Symptom Assessment 45 questionnaire, Hospital Anxiety and Depression Scale, Insomnia Severity Scale, SF-12v2 for physical impairments, and Rivermead Postconcussion Symptoms Questionnaire.

ANALYSIS

Pre-, posttreatment, and follow-up mean scores on questionnaires were assessed using repeated measures 1-way analysis of variance. A Student t test and post hoc analyses were performed on gene expression data.

RESULTS

Post-traumatic stress disorder symptoms declined significantly in the EFT group (-53%, P < .0001). Participants maintained their gains on follow-up. Significant differential expression of 6 genes was found ( P < .05) when comparing the expression levels before and after the intervention period in participants receiving EFT.

CONCLUSION

Study results identify candidate gene expression correlates of successful PTSD treatment, providing guidelines for the design of further studies aimed at exploring the epigenetic effects of EFT.

Altered gene expression of the innate immune, neuroendocrine, and nuclear factor-kappa B (NF-κB) systems is associated with posttraumatic stress disorder in military personnel

Whole transcriptome analysis provides an unbiased examination of biological activity, and likely, unique insight into the mechanisms underlying posttraumatic stress disorder (PTSD) and comorbid depression and traumatic brain injury. This study compared gene-expression profiles in military personnel with PTSD (n=28) and matched controls without PTSD (n=27) using HG-U133 Plus 2.0 microarrays (Affymetrix), which contain 54,675 probe sets representing more than 38,500 genes. Analysis of expression profiles revealed 203 differentially expressed genes in PTSD, of which 72% were upregulated. Using Partek Genomics Suite 6.6, differentially expressed transcription clusters were filtered based on a selection criterion of ≥1.5 relative fold change at a false discovery rate of ≤5%. Ingenuity Pathway Analysis (Qiagen) of the differentially expressed genes indicated a dysregulation of genes associated with the innate immune, neuroendocrine, and NF-κB systems. These findings provide novel insights that may lead to new pharmaceutical agents for PTSD treatments and help mitigate mental and physical comorbidity risk.