Exosomal microRNAs in common mental disorders: Mechanisms, biomarker potential and therapeutic implications

To illustrate the mechanisms of exosomal microRNAs (miRNAs) in common mental disorders, and explore their potential as diagnostic biomarkers and therapeutic targets, a systematic literature review of relevant studies on exosomal miRNAs in mental disorders was conducted. Data from cell experiments, animal models, and clinical studies were analyzed and combined to study the mechanisms and roles of exosomal miRNAs in various mental disorders. Research has shown that exosomal miRNAs, such as miR-146a, miR-223, miR-125b, and miR-451a, affect Alzheimer's disease (AD) formation by regulating key pathways such as toll-like receptor 4 (TLR4) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), respectively. MiR-146a-5p regulates the occurrence of schizophrenia through the Notch pathway. TLR4 regulates miR-146a and miR-155 in major depressive disorder (MDD), and miR-144-5p regulates the disease through PI3K/Akt. Exosomal miR-484, miR-652-3p, miR-142-3p, miR-21a-3p, and miR-21-5p regulate key pathways in bipolar disorder, autism spectrum disorder, and Rett syndrome (e.g., TLR4, PI3K/Akt, and Epha4/TEK) and have an influence on mental disorders. Exosomal miRNAs are involved in the occurrence of mental disorders through TLR4, PI3K/Akt, and Epha4/TEK pathways, which provides a clearer understanding of disease cognition. Of these pathways, the TLR4 and PI3K/Akt pathways play a role in AD, MDD, and neurodevelopmental disorders, which can be used as an effective breakthrough in the study of mental disorders. Exosomal miRNAs could also serve as diagnostic biomarkers and therapeutic targets, providing new insights into precise interventions for mental disorders.