Overexpression of blood microRNAs 103a, 30b, and 29a in l-dopa–treated patients with PD

Objective: The aims of the present study were to profile the expression of several candidate microRNAs (miRNAs) in blood from l-dopa-treated and drug-naive patients with Parkinson disease (PD) vs unaffected controls and to interpret the miRNA expression data in a biological context. Methods: We analyzed RNAs from peripheral blood of 36 l-dopa–treated, 10 drug-naive patients with PD and unaffected controls matched 1:1 by sex and age. We evaluated expression by reverse transcription–quantitative real-time PCR, and we analyzed data using a 2-tailed paired t test. To detect miRNA targets, several miRNA resources were combined to generate an overall score for each candidate gene using weighted rank aggregation. Results: Significant overexpression of miR-103a-3p ( p p = 0.002), and miR-29a-3p ( p = 0.005) in treated patients with PD was observed, and promising candidate target genes for these were revealed by an integrated in silico analysis. Conclusions: We revealed 3 candidate biomarkers for PD. miRNAs 30b-5p and 29a-3p replicated a documented deregulation in PD albeit opposite to published data, while for miR-103a-3p, we demonstrated for the first time an overexpression in treated patients with PD. Expression studies in patients and/or in isolated peripheral blood mononuclear cells before and after l-dopa administration are necessary to define the involvement of l-dopa treatment in the observed overexpression. Our in silico analysis to prioritize targets of deregulated miRNAs identified candidate target genes, including genes related to neurodegeneration and PD. Despite the preliminary character of our study, the results provide a rationale for further clarifying the role of the identified miRNAs in the pathogenesis of PD and for validating their diagnostic potential.