RNA-sequencing of peripheral blood circular RNAs in Parkinson disease

BACKGROUND: Circular RNAs (circRNAs) play an important role in many neurological diseases and can serve as biomarkers for these diseases. However, the information about circRNAs in Parkinson disease (PD) remained limited. In this study, we aimed to determine the circRNAs expression profile in PD patients and discuss the significance of circRNAs in the diagnosis of PD. METHODS AND RESULTS: Using RNA-sequencing in peripheral blood RNAs, we showed that a significant number of mRNAs or circRNAs were differentially expressed between PD patients and normal controls (NCs), which included 273 up-regulated and 493 down-regulated mRNAs, and 129 up-regulated and 282 down-regulated circRNAs, respectively. Functional analysis was performed using the Kyoto Encyclopedia of Gene and Genomes (KEGG) pathway analysis, and the results showed that the second most enriched KEGG pathway was PD. These data suggest that the levels of mRNAs and circRNAs in peripheral blood could be potentially used as biomarkers for PD. In addition, we correlated mRNAs and circRNAs by constructing a competing endogenous RNA (ceRNA) network in PD. The resulted-in ceRNA network included 10 differentially expressed mRNAs from PD pathway, 13 predicted miRNAs, and 10 differentially expressed circRNAs. CONCLUSION: Collectively, we first characterized the expression profiles of circRNAs and mRNAs in peripheral blood from PD patients and proposed their possible characters in the pathogenesis of PD. These results provided valuable insights into the clues underlying the pathogenesis of PD.