MiRNA profile in the substantia nigra of Parkinson's disease and healthy subjects.

The deregulation of several microRNAs (miRNAs) has been associated with neurodegenerative processes, including Parkinson's disease (PD). Our aim was to characterize the level of miRNAs in the substantia nigra (SN) of PD patients and healthy donors. This is an important issue to characterize new putative markers and therapeutic targets for PD. RNA was extracted from the SN of postmortem PD (n=8) and healthy (n=4) subjects, and the level of 733 human miRNAs was assayed with TaqMan low-density arrays (TLDAs). Overall, there was a miRNA downregulation in the SN of patients. The mean level of 11 miRNAs was significantly different (p<0.05) between patients and controls, with 10 downregulated among the patients. MiR-198, -135b, -485-5p, and -548d were the best candidates and were quantified with individual TaqMan assays in the 12 samples. MiR-135b showed the most significant difference between patients and healthy donors. The bioinformatic analysis suggested that this miRNA could bind to genes implicated in several neurodegenerative pathways.