Effects of chronic interpersonal stress exposure on depressive symptoms are moderated by genetic variation at IL6 and IL1β in youth.

TitleEffects of chronic interpersonal stress exposure on depressive symptoms are moderated by genetic variation at IL6 and IL1β in youth.
Publication TypeJournal Article
Year of Publication2015
AuthorsTartter M, Hammen C, Bower JE, Brennan PA, Cole S
JournalBrain Behav Immun
Date Published2015 May
KeywordsAdolescent, Adult, Alleles, Depression, Female, Gene-Environment Interaction, Genetic Predisposition to Disease, Genotype, Humans, Interleukin-1beta, Interleukin-6, Interpersonal Relations, Male, Polymorphism, Single Nucleotide, Promoter Regions, Genetic, Psychiatric Status Rating Scales, Stress, Psychological, Tumor Necrosis Factor-alpha, Young Adult

AIMS: Close to one third of patients with major depression show increases in pro-inflammatory cytokines, which are in turn associated with risk for inflammatory disease. Genetic variants that enhance immune reactivity may thus enhance inflammatory and depressive reactions to stress. The aim of the present study was to investigate a trio of functional SNPs in the promoter regions of IL6 (-174G>C, rs1800795), IL1β (-511C>T, rs16944), and TNF (-308G>A, rs1800629) as moderators of the relationship between chronic stress exposure and elevations in depressive symptoms.

METHODS: Participants were 444 Australian youth (mean age=20.12) whose exposure to chronic stress in the past 6months was assessed using the semi-structured UCLA Life Stress Interview, and who completed the Beck Depression Inventory II at ages 15 and 20. Between ages 22 and 25, all participants in the selected sample provided blood samples for genotyping.

RESULTS: In line with a hypothesized moderation effect, -174G allele carriers at IL6 had fewer depressive symptoms following interpersonal stress, relative to C/C homozygotes with equal interpersonal stress exposure. However, IL6 genotype did not moderate the effects of non-interpersonal stress exposure (i.e., financial, work and health-related difficulties) on depression. Also in line with hypotheses, the -511C allele in IL1β, previously associated with higher IL-1β expression, was associated with more severe depression following chronic interpersonal stress exposure, relative to T/T homozygotes. Again, the moderating effect was specific to interpersonal stressors and did not generalize to non-interpersonal stress. TNF was not a moderator of the effects of either interpersonal or non-interpersonal stress on later depression outcomes.

CONCLUSION: Findings were consistent with the hypothesis that pro-inflammatory genetic variation increases the risk of stress-induced depression. The present results provide evidence of a genetic mechanism contributing to individual differences in depressive symptomatology following interpersonal stress exposure.

Alternate JournalBrain Behav. Immun.
PubMed ID25596176
PubMed Central IDPMC4515110
Grant ListP30 AG017265 / AG / NIA NIH HHS / United States
R01 MH052239 / MH / NIMH NIH HHS / United States
R01 MH52239 / MH / NIMH NIH HHS / United States
T32 MH017140 / MH / NIMH NIH HHS / United States