The role of environmental stress and DNA methylation in the longitudinal course of bipolar disorder

• Main Authors: Ashley L. Comes, Darina Czamara, Kristina Adorjan, Heike Anderson-Schmidt, Till F. M. Andlauer, Monika Budde, Katrin Gade, Maria Hake, Janos L. Kalman, Sergi Papiol, Daniela Reich-Erkelenz, Farah Klöhn-Saghatolislam, Sabrina K. Schaupp, Eva C. Schulte, Fanny Senner, Georg Juckel, Max Schmauß, Jörg Zimmermann, Jens Reimer, Eva Reininghaus, Ion-George Anghelescu, Carsten Konrad, Andreas Thiel, Christian Figge, Martin von Hagen, Manfred Koller, Detlef E. Dietrich, Sebastian Stierl, Harald Scherk, Stephanie H. Witt, Sugirthan Sivalingam, Franziska Degenhardt, Andreas J. Forstner, Marcella Rietschel, Markus M. Nöthen, Jens Wiltfang, Peter Falkai, Thomas G. Schulze, Urs Heilbronner
• Format: Article
• Language: English
• Published: SpringerOpen 2020-02-01
• Series: International Journal of Bipolar Disorders
• Subjects: DNA methylation; Bipolar disorder; Stressful life events; Longitudinal; Epigenomics; Epigenetic aging
• Online Access: https://doi.org/10.1186/s40345-019-0176-6

Abstract Background Stressful life events influence the course of affective disorders, however, the mechanisms by which they bring about phenotypic change are not entirely known. Methods We explored the role of DNA methylation in response to recent stressful life events in a cohort of bipolar patients from the longitudinal PsyCourse study (n = 96). Peripheral blood DNA methylomes were profiled at two time points for over 850,000 methylation sites. The association between impact ratings of stressful life events and DNA methylation was assessed, first by interrogating methylation sites in the vicinity of candidate genes previously implicated in the stress response and, second, by conducting an exploratory epigenome-wide association analysis. Third, the association between epigenetic aging and change in stress and symptom measures over time was investigated. Results Investigation of methylation signatures over time revealed just over half of the CpG sites tested had an absolute difference in methylation of at least 1% over a 1-year period. Although not a single CpG site withstood correction for multiple testing, methylation at one site (cg15212455) was suggestively associated with stressful life events (p < 1.0 × 10−5). Epigenetic aging over a 1-year period was not associated with changes in stress or symptom measures. Conclusions To the best of our knowledge, our study is the first to investigate epigenome-wide methylation across time in bipolar patients and in relation to recent, non-traumatic stressful life events. Limited and inconclusive evidence warrants future longitudinal investigations in larger samples of well-characterized bipolar patients to give a complete picture regarding the role of DNA methylation in the course of bipolar disorder.