Ursano, R. J. | bioRxiv Science

bioRxiv2019

Epigenome-wide meta-analysis of PTSD across 10 military and civilian cohorts identifies novel methylation loci

Differences in susceptibility to posttraumatic stress disorder (PTSD) may be related to epigenetic differences between PTSD cases and trauma-exposed controls. Such epigenetic differences may provide insight into the biological processes underlying the disorder. Here we describe the results of the largest DNA methylation meta-analysis of PTSD to date with data from the Psychiatric Genomics Consortium (PGC) PTSD Epigenetics Workgroup. Ten cohorts, military and civilian, contributed blood-derived DNA methylation data (HumanMethylation450 BeadChip) from 1,896 PTSD cases (42%) and trauma-exposed controls (58%). Utilizing a common QC and analysis strategy, we identified ten CpG sites associated with PTSD (9.61E-07<p<4.72E-11) after adjustment for multiple comparisons (FDR<.05). Several CpGs were located in genes previously implicated in PTSD and other psychiatric disorders. The top four CpG sites fell within the aryl-hydrocarbon receptor repressor (AHRR) locus and were associated with lower DNA methylation in PTSD cases relative to controls. Interestingly, this association appeared to uncorrelated with smoking status and was most pronounced in non-smokers with PTSD. Additional evaluation of metabolomics data supported our findings and revealed that AHRR methylation associated with kynurenine levels, which were lower among subjects with PTSD relative to controls. Overall, this study supports epigenetic differences in those with PTSD and suggests a role for decreased kynurenine as a contributor to immune dysregulation in PTSD.

genomics↗

bioRxiv2019

Genomewide Analyses of Psychological Resilience in US Army Soldiers

Though a growing body of preclinical and translational research is illuminating a biological basis for resilience to stress, little is known about the genetic basis of psychological resilience in humans. We conducted genomewide association studies (GWAS) of self-assessed (by questionnaire) and outcome-based (incident mental disorders from pre- to post-deployment) resilience among European (EUR) ancestry soldiers in the Army Study To Assess Risk and Resilience in Servicemembers (STARRS). Self-assessed resilience (N=11,492) was found to have significant common-variant heritability (h2=0.162, se=0.050, p=5.37e-4), and to be significantly negatively genetically correlated with neuroticism (rg= -0.388, p=0.0092). GWAS results from the EUR soldiers revealed a genomewide significant locus (4 SNPs in LD; top SNP: rs4260523, p=5.654e-09) on an intergenic region on Chr 4 upstream from DCLK2 (Doublecortin-Like Kinase 2), a member of the doublecortin (DCX) family of kinases that promote survival and regeneration of injured neurons. A second gene, KLHL36 (Kelch Like Family Member 36) was detected at gene-wise genomewide significance (p=1.89e-06). A polygenic risk score derived from the self-assessed resilience GWAS was not significantly associated with outcome-based resilience. In very preliminary results, genomewide significant association with outcome-based resilience was found for one locus (top SNP: rs12580015) on Chr 12 downstream from SLC15A5 (solute carrier family 15 member 5) in the small group (N=581) of subjects exposed to the highest level of deployment stress. The further study of genetic determinants of resilience has the potential to illuminate the molecular bases of stress-related psychopathology and potentially point to new avenues for therapeutic intervention.

genetics↗