Epigenetic and genomic mechanisms in the pathogenesis of posttraumatic stress disorder (review)

Background: Posttraumatic stress disorder is one of the most prominent examples of gene-environment interactions. Psychological traumatization is a dominant, but not the only etiological factor. Over the past 20 years, sufficient data have been accumulated to confirm the role of the hereditary component in the formation of the so-called "vulnerable phenotype”. Epigenetic modifications are considered as a mechanism for environmental (traumatic) exposure provoking changes in gene expression and genome stability, which can lead to specific symptoms. The aim of the study: To summarize and to compare the essential results of studies of epigenetic mechanisms of genome regulation in posttraumatic stress disorder. Materials and methods: A theoretical analysis of the published studies dedicated to epigenetic markers of posttraumatic stress disorder was carried out. The PubMed database was browsed in the aforementioned context. Results: The studies published during the last decades have a number of common characteristics (reliance on retrospective data about a traumatic event obtained by the self-report method; use of available tissues for analysis; use of a retrospective cross-sectional design). The systematics of research is based on both the dominant methodology (search and study of candidate genes; methods of whole-genome or epigenome associations) and the analysis of DNA methylation, posttranslational modifications of histones, and chromatin structural organization. The pathogenesis of posttraumatic stress disorder is also explained in the context of cytogenomic hypothesis (changes in genome instability levels modulate behavior). The limitations and prospects of studying epigenetic mechanisms in the pathogenesis of posttraumatic stress disorder are outlined. Conclusion: Epigenetic and genomic analyses of the molecular basis of PTSD offer the Обзор Review Научные результаты биомедицинских исследований. 2022;8(1):15-35 Research Results in Biomedicine. 2022:8(1):15-35 17 most holistic approach to understanding the interaction between genotype and environment presenting as a traumatic event. The study of epigenetic modifications and genome instability, which are potentially reversible, will contribute to the improvement of the prevention and the provision of clinical and psychological assistance to individuals who have experienced traumatic events.