MicroRNAs in posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is a psychiatric disorder that can develop following exposure to, or witnessing a (potentially) traumatic event. A critical issue is to pinpoint (neuro)biological mechanisms underlying susceptibility to stress-related disorders such as PTSD. Over the last few years, a first wave of epigenetic studies has attempted to identify molecular underpinnings of the long-lasting effects of trauma exposure. The potential roles of noncoding RNAs (ncRNAs) such as microRNAs (miRNAs) in regulating the impact of severe stress and trauma are increasingly gaining attention. The present review offers an overview of studies of miRNAs in PTSD and discusses the current challenges, pitfalls, and future perspectives of the field. Most studies have been completed in animals, using cross-sectional study designs and focusing on susceptible phenotypes only. Moreover, due to an increase in the number of animal and human studies including both males and females, several recent studies reveal sex-dependent mechanisms related to stress exposure. However, there is a strong need for future research to comprise more translational, cross-species, and cross-tissue approaches that use longitudinal designs to study trajectories of change contrasting both susceptible and resilient subjects.