Correlates of chronic stress and their influence on the development of substance use in a population-based cohort of young adults (OYSUP)
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ABSTRACT: Background: We seek to understand correlates of chronic stress and their influence on the development of substance use in a population-based cohort of young adults (OYSUP). Methodology: We evaluated clinical features, salivary RNA metrics and differential expression of candidate genes in unfractionated saliva samples from 48 individuals (31% female, 55% ever-smoking) randomly selected from two groups stratified by high versus low severe negative life events and difficulties within the last year as as measured by the Life Events and Difficulties Schedule (LEDS, Brown & Harris, 1978). We used multiple analytical platforms, multiple reference genes and 18 replicates of all gene expression assays (assays). We chose 38 candidate genes previously identified as differentially expressed in a genome-wide scan of monocyte RNA in 11 familial caregivers of glioblastoma multiforme patients and 10 control subjects matched on age (middle-aged), gender (57% female), ethnicity and marital status and free of major stressors during the previous year. Principal Findings: We observed significant differences in smoking prevalence (Pearson’s χ22d.f.=4.5, P=0.035) and RNA integrity score (t=2.12, P=0.039) between stress strata. We analyzed quantitative PCR data using both the comparative standard curve (CSC) and relative standard curve (RSC) methods because 34% of assays had efficiency estimates <90%. Assay data exhibited excellent linearity and low variability. We observed significant under expression of five assays in the high stress stratum using both methods, four of which interrogate glucocorticoid receptor regulated genes. Post-hoc analyses identified significant associations of RNA yield, integrity score, gender, ever-smoking and/or stress with results of normalized gene expression in 22/37 assays. IL8 expression remained significantly associated with chronic stress after adjustment for clinical and salivary RNA variables. Salivary IL8 expression has been previously associated with oropharyngeal squamous cell cancer. Conclusions: A gene expression signature of chronic stress previously observed in adult hematopoietic samples is observed in the unfractionated saliva of young adults. Future investigation will need to analyze associated clinical, metabolic, meta-genomic, and proteomic components of unfractionated saliva to elucidate factors influencing the salivary transcriptome.
ORGANISM(S): Homo sapiens
PROVIDER: GSE27144 | GEO | 2012/06/15
SECONDARY ACCESSION(S): PRJNA137571
REPOSITORIES: GEO
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