BACKGROUND: Longevity gene klotho (KL) is associated with age-related phenotypes including lifespan, cardiometabolic disorders, cognition, and brain morphology, in part, by conferring protection against inflammation. We hypothesized that the KL/inflammation association might be altered in the presence of psychiatric stress and operate via epigenetic pathways. We examined KL polymorphisms, and their interaction with posttraumatic stress disorder (PTSD) symptoms, in association with KL DNA methylation in blood. We further examined KL DNA methylation as a predictor of longitudinal changes in a peripheral biomarker of inflammation (C-reactive protein; CRP). METHODS: The sample comprised 309 white non-Hispanic military veterans (93.5% male; mean age: 32 years, range: 19-65; 30% PTSD per structured diagnostic interview); 111 were reassessed approximately two years later. RESULTS: Analyses revealed a methylation quantitative trait locus at rs9527025 (C370S, previously implicated in numerous studies of aging) in association with a Cytosine-phosphate-Guanine site (cg00129557; B = −.65, p = 1.29 X 10(−20)), located within a DNase hypersensitivity site in the body of KL. There was also a rs9527025 x PTSD severity interaction (B = .004, p = .035) on methylation at this locus such that the minor allele was associated with reduced cg00129557 methylation in individuals with few or no PTSD symptoms while this effect was attenuated in those with elevated levels of PTSD. Path models revealed that methylation at cg00129557 was inversely associated with CRP over time (B = −.14, p = .005), controlling for baseline CRP. There was also an indirect effect of rs9527025 X PTSD on subsequent CRP via cg00129557 methylation (indirect B = −.002, p = .033). CONCLUSIONS: Results contribute to our understanding of the epigenetic correlates of inflammation in PTSD and suggest that KL methylation may be a mechanism by which KL genotype confers risk vs. resilience to accelerated aging in those experiencing traumatic stress.
In: Logue , M W , Miller , M W , Wolf , E J , Huber , B R , Morrison , F G , Zhou , Z , Zheng , Y , Smith , A K , Daskalakis , N P , Ratanatharathorn , A , Uddin , M , Nievergelt , C M , Ashley-Koch , A E , Baker , D G , Beckham , J C , Garrett , M E , Boks , M P , Geuze , E , Grant , G A , Hauser , M A , Kessler , R C , Kimbrel , N A , Maihofer , A X , Marx , C E , Qin , X-J , Risbrough , V B , Rutten , B P F , Stein , M B , Ursano , R J , Vermetten , E , Vinkers , C H , Ware , E B , Stone , A , Schichman , S A , McGlinchey , R E , Milberg , W P , Hayes , J P , Verfaellie , M & Traumatic Stress Brain Study Group 2020 , ' An epigenome-wide association study of posttraumatic stress disorder in US veterans implicates several new DNA methylation loci ' , Clinical epigenetics , vol. 12 , no. 1 , 46 . https://doi.org/10.1186/s13148-020-0820-0
Background Previous studies using candidate gene and genome-wide approaches have identified epigenetic changes in DNA methylation (DNAm) associated with posttraumatic stress disorder (PTSD). Methods In this study, we performed an EWAS of PTSD in a cohort of Veterans (n = 378 lifetime PTSD cases and 135 controls) from the Translational Research Center for TBI and Stress Disorders (TRACTS) cohort assessed using the Illumina EPIC Methylation BeadChip which assesses DNAm at more than 850,000 sites throughout the genome. Our model included covariates for ancestry, cell heterogeneity, sex, age, and a smoking score based on DNAm at 39 smoking-associated CpGs. We also examined in EPIC-based DNAm data generated from pre-frontal cortex (PFC) tissue from the National PTSD Brain Bank (n = 72). Results The analysis of blood samples yielded one genome-wide significant association with PTSD at cg19534438 in the gene G0S2 (p = 1.19 x 10(-7), p(adj) = 0.048). This association was replicated in an independent PGC-PTSD-EWAS consortium meta-analysis of military cohorts (p = 0.0024). We also observed association with the smoking-related locus cg05575921 in AHRR despite inclusion of a methylation-based smoking score covariate (p = 9.16 x 10(-6)), which replicates a previously observed PGC-PTSD-EWAS association (Smith et al. 2019), and yields evidence consistent with a smoking-independent effect. The top 100 EWAS loci were then examined in the PFC data. One of the blood-based PTSD loci, cg04130728 in CHST11, which was in the top 10 loci in blood, but which was not genome-wide significant, was significantly associated with PTSD in brain tissue (in blood p = 1.19 x 10(-5), p(adj) = 0.60, in brain, p = 0.00032 with the same direction of effect). Gene set enrichment analysis of the top 500 EWAS loci yielded several significant overlapping GO terms involved in pathogen response, including "Response to lipopolysaccharide" (p = 6.97 x 10(-6), p(adj) = 0.042). Conclusions The cross replication observed in independent cohorts is evidence that ...
To reveal post-traumatic stress disorder (PTSD) genetic risk influences on tissue-specific gene expression, we use brain and non-brain transcriptomic imputation. We impute genetically regulated gene expression (GReX) in 29,539 PTSD cases and 166,145 controls from 70 ancestry-specific cohorts and identify 18 significant GReX-PTSD associations corresponding to specific tissue-gene pairs. The results suggest substantial genetic heterogeneity based on ancestry, cohort type (military versus civilian), and sex. Two study-wide significant PTSD associations are identified in European and military European cohorts; ZNF140 is predicted to be upregulated in whole blood, and SNRNP35 is predicted to be downregulated in dorsolateral prefrontal cortex, respectively. In peripheral leukocytes from 175 marines, the observed PTSD differential gene expression correlates with the predicted differences for these individuals, and deployment stress produces glucocorticoid-regulated expression changes that include downregulation of both ZNF140 and SNRNP35. SNRNP35 knockdown in cells validates its functional role in U12-intron splicing. Finally, exogenous glucocorticoids in mice downregulate prefrontal Snrnp35 expression.
To reveal post-traumatic stress disorder (PTSD) genetic risk influences on tissue-specific gene expression, we use brain and non-brain transcriptomic imputation. We impute genetically regulated gene expression (GReX) in 29,539 PTSD cases and 166,145 controls from 70 ancestry-specific cohorts and identify 18 significant GReX-PTSD associations corresponding to specific tissue-gene pairs. The results suggest substantial genetic heterogeneity based on ancestry, cohort type (military versus civilian), and sex. Two study-wide significant PTSD associations are identified in European and military European cohorts; ZNF140 is predicted to be upregulated in whole blood, and SNRNP35 is predicted to be downregulated in dorsolateral prefrontal cortex, respectively. In peripheral leukocytes from 175 marines, the observed PTSD differential gene expression correlates with the predicted differences for these individuals, and deployment stress produces glucocorticoid-regulated expression changes that include downregulation of both ZNF140 and SNRNP35. SNRNP35 knockdown in cells validates its functional role in U12-intron splicing. Finally, exogenous glucocorticoids in mice downregulate prefrontal Snrnp35 expression.
In: Smith , A K , Ratanatharathorn , A , Maihofer , A X , Naviaux , R K , Aiello , A E , Amstadter , A B , Ashley-Koch , A E , Baker , D G , Beckham , J C , Boks , M P , Bromet , E , Dennis , M , Galea , S , Garrett , M E , Geuze , E , Guffanti , G , Hauser , M A , Katrinli , S , Kilaru , V , Kessler , R C , Kimbrel , N A , Koenen , K C , Kuan , P F , Li , K , Logue , M W , Lori , A , Luft , B J , Miller , M W , Naviaux , J C , Nugent , N R , Qin , X , Ressler , K J , Risbrough , V B , Rutten , B P F , Stein , M B , Ursano , R J , Vermetten , E , Vinkers , C H , Wang , L , Youssef , N A , Marx , C , Grant , G , Stein , M , Qin , X J , Jain , S , McAllister , T W , Zafonte , R , Lang , A , Coimbra , R , Andaluz , N , Shutter , L , George , M S , Brancu , M , Calhoun , P S , Dedert , E , Elbogen , E B , Fairbank , J A , Hurley , R A , Kilts , J D , Kirby , A , Marx , C E , McDonald , S D , Moore , S D , Morey , R A , Naylor , J C , Rowland , J A , Swinkels , C , Szabo , S T , Taber , K H , Tupler , L A , Van Voorhees , E E , Yoash-Gantz , R E , Basu , A , Brick , L A , Dalvie , S , Daskalakis , N P , Ensink , J B M , Hemmings , S M J , Herringa , R , Ikiyo , S , Koen , N , Kuan , P F , Montalvo-Ortiz , J , Nispeling , D , Pfeiffer , J , Qin , X J , Ressler , K J , Schijven , D , Seedat , S , Shinozaki , G , Sumner , J A , Swart , P , Tyrka , A , Van Zuiden , M , Wani , A , Wolf , E J , Zannas , A , Uddin , M , Nievergelt , C M , INTRuST Clinical Consortium , VA Mid-Atlantic MIRECC Workgroup & PGC PTSD Epigenetics Workgroup 2020 , ' Epigenome-wide meta-analysis of PTSD across 10 military and civilian cohorts identifies methylation changes in AHRR ' , Nature Communications , vol. 11 , no. 1 , 5965 . https://doi.org/10.1038/s41467-020-19615-x
Epigenetic differences may help to distinguish between PTSD cases and trauma-exposed controls. Here, we describe the results of the largest DNA methylation meta-analysis of PTSD to date. Ten cohorts, military and civilian, contribute blood-derived DNA methylation data from 1,896 PTSD cases and trauma-exposed controls. Four CpG sites within the aryl-hydrocarbon receptor repressor (AHRR) associate with PTSD after adjustment for multiple comparisons, with lower DNA methylation in PTSD cases relative to controls. Although AHRR methylation is known to associate with smoking, the AHRR association with PTSD is most pronounced in non-smokers, suggesting the result was independent of smoking status. Evaluation of metabolomics data reveals that AHRR methylation associated with kynurenine levels, which are lower among subjects with PTSD. This study supports epigenetic differences in those with PTSD and suggests a role for decreased kynurenine as a contributor to immune dysregulation in PTSD.