Dysregulated miR-1246 and miR-1253 link inflammatory protein markers in plasma to major depressive disorder in female adolescents.

Major depressive disorder (MDD) in adolescents is a prevalent psychiatric condition worldwide with severe consequences. Growing evidence shows that microRNAs (miRNAs) regulate many processes hypothesized to be involved in the pathogenesis of MDD including inflammation, suggesting their suitability as biomarkers. Still, more research is needed regarding miRNAs as biomarkers and the role of inflammation in adolescents with MDD. This study applied the NanoString nCounter technology to identify dysregulated miRNAs in plasma from hospitalized female adolescents with MDD compared to healthy controls, as well as before and after antidepressant treatment. A multiplexed immunoassay was also performed to assess the plasma levels of 27 inflammatory proteins. A total of 33 patients and 14 healthy controls were included in the study. miR-1246 and miR-1253 were downregulated in female adolescents with MDD compared to healthy controls, suggesting their potential as diagnostic biomarkers. Additionally, miR-496 was downregulated with treatment, indicating its potential as a prognostic biomarker. Moreover, increased levels of PDGF-BB and IL-7 were seen in adolescents with MDD compared to healthy controls, while IL-9 and MIP-1β levels decreased with antidepressant treatment. Finally, the expression of specific miRNAs were found to correlate with the levels of several inflammatory proteins. In summary, miR-1246, miR-1253, and miR-496 are suggested as potential diagnostic and prognostic biomarkers. Furthermore, this study contributes in more detail to our understanding of miRNAs, inflammation, and MDD in female adolescents.