Abstract
OBJECTIVE: Bipolar I disorder (BD-I) is a type of bipolar spectrum disorder characterized by manic or mixed episodes. Detecting microRNA regulations as epigenetic actors in BD-I is important to elucidate the pathogenesis of the disease and reveal the potential of microRNAs (miRNAs) as biomarkers. METHODS: We evaluated the expression profile of six candidate miRNAs (hsa-miR-145-5p, hsa-miR-376a-3p, hsa-miR-3680-5p, hsa-miR-4253-5p, hsa-miR-4482-3p, and hsa-miR-4725) in patients with BD-I and in healthy controls (aged 11-50 years). We also determined the potential target genes of these miRNAs through in silico analysis. The diagnostic values of the miRNAs were calculated through receiver operating characteristic curve analysis. RESULTS: Four miRNAs were upregulated (hsa-miR-376a-3p, hsa-miR-3680-5p, hsa-miR-4253-5p, hsa-miR-4482-3p) and hsa-miR-145-5p was downregulated in patients (p < 0.001). The target gene analyses showed that hsa-miR-145-5p specifically targets the dopamine decarboxylase (DDC) gene. The area under the curve of hsa-miR-145-5p was 0.987. CONCLUSION: Differential expression of five miRNAs in peripheral blood may be associated with the pathogenesis of BD-I, and hsa-miR-145-5p has potential as a BD-I biomarker. This miRNA can be used in dopamine-serotonin regulation and dose adjustment in drug therapy via the DDC gene.