Brain-enriched MicroRNA-184 is downregulated in older adults with major depressive disorder: A translational study

Changes in microRNAs (miRNAs) expression have been described in major depressive disorder in young and middle-aged adults. However, no study has evaluated miRNA expression in older adults with major depression (or late-life depression [LLD]). Our primary aim was to evaluate the expression of miRNAs in subjects with LLD. We first evaluated the miRNA expression using next-generation sequencing (NGS) and then we validated the miRNAs found in NGS in an independent sample of LLD patients, using RT-qPCR. Drosophila melanogaster model was used to evaluate the impact of changes in miRNA expression on behavior. NGS analysis showed that hsa-miR-184 (log2foldchange = −4.21, p = 1.2 × 10−03) and hsa-miR-1-3p (log2foldchange = −3.45, p = 1.3 × 10−02) were significantly downregulated in LLD compared to the control group. RT-qPCR validated the downregulation of hsa-miR-184 (p