Sirignano et al. Translational Psychiatry (2021) 11:347 https://doi.org/10.1038/s41398-021-01474-9 Translational Psychiatry ARTICLE Open Access Methylome-wide change associated with response to electroconvulsive therapy in depressed patients Lea Sirignano 1,JosefFrank 1, Laura Kranaster 2, Stephanie H. Witt 1,FabianStreit 1, Lea Zillich1, Alexander Sartorius2, Marcella Rietschel 1 and Jerome C. Foo 1 Abstract Electroconvulsive therapy (ECT) is a quick-acting and powerful antidepressant treatment considered to be effective in treating severe and pharmacotherapy-resistant forms of depression. Recent studies have suggested that epigenetic mechanisms can mediate treatment response and investigations about the relationship between the effects of ECT and DNA methylation have so far largely taken candidate approaches. In the present study, we examined the effects of ECT on the methylome associated with response in depressed patients (n = 34), testing for differentially methylated CpG sites before the first and after the last ECT treatment. We identified one differentially methylated CpG site associated with the effect of ECT response (defined as >50% decrease in Hamilton Depression Rating Scale score, HDRS), TNKS (q < 0.05; p = 7.15 × 10−8). When defining response continuously (ΔHDRS), the top suggestive differentially methylated CpG site was in FKBP5 (p = 3.94 × 10−7). Regional analyses identified two differentially methylated regions on chromosomes 8 (Šídák’s p = 0.0031) and 20 (Šídák’s p = 4.2 × 10−5) associated with ΔHDRS. Functional pathway analysis did not identify any significant pathways. A confirmatory look at candidates previously proposed to be involved in ECT mechanisms found CpG sites associated with response only at the nominally significant level (p < 0.05). Despite the limited sample size, the present study was able to identify epigenetic change associated with ECT response suggesting that this approach, especially when involving larger 1234567890():,; 1234567890():,; 1234567890():,; 1234567890():,; samples, has the potential to inform the study of mechanisms involved in ECT and severe and treatment-resistant depression. Introduction ECT in such a subgroup of severely depressed patients is a Depression is a major contributor to global burden of promising approach to gain insights into the underlying disease and despite worldwide research efforts, the het- mechanisms of depression and treatment response. erogeneous nature of the disorder makes it difficult to DNA methylation is thought to be involved in disease definitively unravel its underlying etiology and the factors pathology through its influence on gene expression and influencing treatment response1,2. Electroconvulsive cellular function5,6. There is evidence that pre-treatment therapy (ECT) is an intervention with rapid and striking methylation profiles may predict likelihood of achieving antidepressant effects and is the treatment of choice for remission7 and the literature on DNA methylation in patients with severe and treatment-resistant depression3,4. depression has pointed to several possible genes of interest Studying biological changes associated with response to (e.g., BDNF, SLC6A4, NR3C1, FKBP5, etc. for reviews, – see7 10) as being related to antidepressant response. Investigating change of methylation levels during treat- Correspondence: Jerome C. Foo ([email protected]) 1Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental ment may inform the biological processes underlying both Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, depression and antidepressant response. Examining these Germany changes in ECT patients offers an optimal research setting 2Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, as: (1) treatment effects are substantial and occur soon Germany © The Author(s) 2021 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a linktotheCreativeCommons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Sirignano et al. Translational Psychiatry (2021) 11:347 Page 2 of 9 after the intervention, and (2) ECT patients represent a Materials and methods subgroup of patients with the most severe form of This study was approved by the Ethics Committee (II), depression. It is likely that this subgroup is not only Medical Faculty Mannheim, University of Heidelberg. All clinically but also genetically more homogenous, especially patients provided written consent after a detailed expla- as these patients tend to show a higher genetic burden for nation of the content of the study. All experimental major depression than those with less severe forms11. procedures were performed in accordance with the The few studies exploring differences in methylation Declaration of Helsinki. related to ECT are only beginning to give insight into the factors involved. A translational study observed that the Participants response to electroconvulsive stimulation (ECS) in rats Patients (n = 34) diagnosed with a major unipolar was predicted by higher p11 promoter methylation and depressive episode (based on International Classification found this also to be the case in two human samples (n = of Diseases version 10, ICD-10), older than 18 years, 11; n = 65) in response to ECT12. Another candidate and assigned to ECT treatment were recruited at the gene is brain-derived neurotrophic factor (BDNF)which Department of Psychiatry and Psychotherapy at the is involved in neuroplastic changes associated with stress Central Institute of Mental Health (CIMH) in Mannheim, and depression13,14. Methylation differences of the pro- Germany, between 2014 and 2016. Criteria for assignment moter region of BDNF have been observed in many to ECT were treatment-resistant depression (i.e., failure of psychiatric disorders15, and also after use of anti- two adequate dose-duration antidepressants from differ- depressant medication16. Studies in animals and humans ent classes, or psychotherapy in the current episode), also propose an involvement of BDNF in response to positive experience of ECT from a previous episode, or ECT: after ECS/ECT, alterations of BDNF levels have severe depression with (a) psychotic symptoms, (b) severe been found in rats17, and in humans, differences in suicidality, or (c) the refusal of food or fluid intake. expression of BDNF have been described18,19. Further- Patients were excluded if they had any substance-use- more, associations between pre-treatment BDNF levels related disorders (other than tobacco and alcohol use and ECT outcome have been described, but whether disorders) or a lifetime diagnosis of schizophrenia. All BDNF levels are indicative of response remains to be participants were of Caucasian descent. The patients kept determined20,21. the same medication regimens throughout ECT treat- Research on ECT-related changes in methylation levels ment. This sample is a subset of a sample reported in a has largely focused on candidate genes. However, as ECT previous genetic study in ECT patients11. Descriptive and is a non-specific treatment with widespread, yet uncertain clinical characteristics of the participants are described effects on biological processes, the selection of predefined in Table 1. candidates, relying on prior knowledge may not give the full picture. As such, an approach investigating the whole Depression and DNA methylation assessment methylome is expected to yield new and relevant insights. The 21-item version of the Hamilton Depression Rating Few studies have made use of these technologies in ECT Scale (HDRS) was administered and blood was collected samples to date. Moschny et al.22 examined longitudinal from patients prior to the first (T1) and after the last DNA methylation before and after ECT in a small group (T2) session of ECT (average sessions: 10.82, range: of patients (8 responders and 4 non-responders). They did 5–25 sessions). T2 was between 1 and 7 days after the last not find any significant differences in global DNA ECT session. Time of collection was kept constant methylation, but identified eight genes potentially impli- between 8:30 and 9:30 a.m. at both timepoints to keep it cated in either ECT response or its mechanism through close to the clinical interview conducted around the same analysis of single probe variance, and two genes whose time, as well as preclude any potential confounding methylation changed during treatment course. effects arising from ward routines and circadian fluctua- In the present study, we aimed to identify changes in tions23,24. Standard procedures for extraction and pro- methylation levels associated with the effects of ECT and cessing were followed. DNA extraction was performed to find potential biomarkers for antidepressant response. using the Chemagic Magnetic Separation