Impact of MicroRNAs in synaptic plasticity, major affective disorders, and suicidal behavior

Major affective disorders are common conditions associated with relevant disability, psychosocial impairment, and suicidal behavior. Both affective disorders and suicidal behavior have been associated with impairments in synaptic plasticity and cellular resilience. It has been suggested that small noncoding RNAs, especially microRNAs (miRNAs) may be implicated in the pathogenesis of major affective disorders playing a critical role in the translational regulation at the synapse. In the present chapter, we aimed to carefully review the current literature about the impact of miRNAs on neurogenesis, synaptic plasticity, pathological changes induced by chronic stress, and major affective disorders including suicidal behavior. MiRNAs played a critical role in the evolution of the most important brain functions; they represent a relevant class of gene expression regulators involved in the development, physiology, and diseases of the central nervous system. Consistent evidence suggested that abnormalities of some intracellular mechanisms together with impaired assembly, localization, and translational regulation of specific RNA-binding proteins may significantly contribute to the pathogenesis of major affective disorders. At a molecular level, measurements of miRNAs may comprehensively help to understand how gene expression networks are reorganized in both major depression and/or suicide. The present chapter aimed to discuss the main implications of the studies analyzing the association between miRNAs, major affective disorders, and suicidal behavior.