Fatigue is highly prevalent in the general population and is one of the most common side effects of cancer treatment. There is growing evidence that pro-inflammatory cytokines play a role in ...cancer-related fatigue, although the molecular mechanisms for chronic inflammation and fatigue have not been determined. The current study utilized genome-wide expression microarrays to identify differences in gene expression and associated alterations in transcriptional activity in leukocytes from breast cancer survivors with persistent fatigue (n =11) and non-fatigued controls (n =10). We focused on transcription of inflammation-related genes, particularly those responsive to the pro-inflammatory NF-IordmB transcription control pathway. Further, given the role of glucocorticoids as key regulators of inflammatory processes, we examined transcription of glucocorticoid-responsive genes indicative of potential glucocorticoid receptor (GR) desensitization. Plasma levels of cortisol were also assessed. Consistent with hypotheses, results showed increased expression of transcripts with response elements for NF-IordmB, and reduced expression of transcripts with response elements for glucocorticoids (p <.05) in fatigued breast cancer survivors. No differences in plasma levels of cortisol were observed. These data indicate that increased activity of pro-inflammatory transcription factors may contribute to persistent cancer-related fatigue and provide insight into potential mechanisms for tonic increases in NF-IordmB activity, specifically decreased expression of GR anti-inflammatory transcription factors.
Research in human social genomics has identified a conserved transcriptional response to adversity (CTRA) characterized by up-regulated expression of pro-inflammatory genes and down-regulated ...expression of Type I interferon- and antibody-related genes. This report seeks to identify the specific aspects of positive psychological well-being that oppose such effects and predict reduced CTRA gene expression. In a new confirmation study of 122 healthy adults that replicated the approach of a previously reported discovery study, mixed effect linear model analyses identified a significant inverse association between expression of CTRA indicator genes and a summary measure of eudaimonic well-being from the Mental Health Continuum - Short Form. Analyses of a 2- representation of eudaimonia converged in finding correlated psychological and social subdomains of eudaimonic well-being to be the primary carriers of CTRA associations. Hedonic well-being showed no consistent CTRA association independent of eudaimonic well-being, and summary measures integrating hedonic and eudaimonic well-being showed less stable CTRA associations than did focal measures of eudaimonia (psychological and social well-being). Similar results emerged from analyses of pooled discovery and confirmation samples (n = 198). Similar results also emerged from analyses of a second new generalization study of 107 healthy adults that included the more detailed Ryff Scales of Psychological Well-being and found this more robust measure of eudaimonic well-being to also associate with reduced CTRA gene expression. Five of the 6 major sub-domains of psychological well-being predicted reduced CTRA gene expression when analyzed separately, and 3 remained distinctively prognostic in mutually adjusted analyses. All associations were independent of demographic characteristics, health-related confounders, and RNA indicators of leukocyte subset distribution. These results identify specific sub-dimensions of eudaimonic well-being as promising targets for future interventions to mitigate CTRA gene expression, and provide no support for any independent favorable contribution from hedonic well-being.
To identify signaling pathways by which the sympathetic nervous system (SNS) might alter gene expression in the immune system, we assayed activation of the inflammatory transcription factor NF-kappaB ...in peripheral blood mononuclear cells (PBMC) from 13 healthy young adults at rest and following 5 min of intense exercise. SNS activation was verified by changes in cardiovascular parameters and mobilization of NK cells into circulating blood. Electrophoretic mobility shift assays (EMSA) of nuclear protein extracts confirmed previous findings that SNS activation increased NF-kappaB DNA-binding activity in bulk PBMC. However, analyses of isolated leukocyte subsets failed to indicate any increase on a per-cell basis in NK cells (the major carriers of NF-kappaB activity in circulating PBMC), in the residual CD56- leukocyte pool, or in CD14+ monocytes. Regression analyses indicated a strong correlation between increasing NK cell prevalence and changes in NF-kappaB DNA-binding activity in bulk PBMC, and suggested that no change in EMSA activity would be observed in the absence of NK cell mobilization. Such results imply that SNS-induced mobilization of NK cells can rapidly (< 10 min) alter NF-kappaB DNA-binding activity in the circulating PBMC pool without generating any true change in NF-kappaB activity on a per-cell basis. Implications for future efforts to analyze stress effects on leukocyte gene expression are considered.
Chronic stressors are known to increase vulnerability to medical illness, but the mechanisms underlying this phenomenon are poorly understood.
To identify transcriptional control pathways that are ...modified by chronic stress, we conducted genomewide expression microarrays on familial caregivers of brain-cancer patients (n = 11) and matched control subjects (n = 10). Analyses were conducted on peripheral blood monocytes, which are cells that have the ability to initiate and maintain many inflammatory responses. Salivary cortisol was collected over the course of 3 days as volunteers went about normal activities.
Caregivers' patterns of cortisol secretion were similar to those of matched control subjects. However, their monocytes showed diminished expression of transcripts bearing response elements for glucocorticoids, and heightened expression of transcripts with response elements for NF-kappaB, a key pro-inflammatory transcription factor. Caregivers also showed relative elevations in the inflammatory markers C-reactive protein and interleukin-1 receptor antagonist.
These findings suggest that even in the absence of excess adrenocortical output, stress brings about functional resistance to glucocorticoids in monocytes, which enables activation of pro-inflammatory transcription control pathways. This persistent activation of inflammatory mechanisms may contribute to stress-related morbidity and mortality.
Genome-wide transcriptional profiling has emerged as a powerful tool for analyzing biological mechanisms underlying social gradients in health, but utilization in population-based studies has been ...hampered by logistical constraints and costs associated with venipuncture blood sampling. Dried blood spots (DBS) provide a minimally invasive, low-cost alternative to venipuncture, and in this article we evaluate how closely the substantive results from DBS transcriptional profiling correspond to those derived from parallel analyses of gold-standard venous blood samples (PAXgene whole blood and peripheral blood mononuclear cells PBMC). Analyses focused on differences in gene expression between African-Americans and Caucasians in a community sample of 82 healthy adults (age 18-70 years; mean 35). Across 19,679 named gene transcripts, DBS-derived values correlated r = .85 with both PAXgene and PBMC values. Results from bioinformatics analyses of gene expression derived from DBS samples were concordant with PAXgene and PBMC samples in identifying increased Type I interferon signaling and up-regulated activity of monocytes and natural killer (NK) cells in African-Americans compared to Caucasian participants. These findings demonstrate the feasibility of DBS in field-based studies of gene expression and encourage future studies of human transcriptome dynamics in larger, more representative samples than are possible with clinic- or lab-based research designs.
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