Elevated Serum Level of MicroRNA (miRNA)-200c and miRNA-371-5p in Children with Kawasaki Disease

MicroRNAs (miRNAs) are small, non-coding RNAs that regulate the expression of protein-coding genes. Recently, miRNA levels have been used as a novel non-invasive biomarker for the diagnosis of various diseases. We aimed to identify serum miRNAs elevated in patients with Kawasaki disease (KD) and to explore the potential biological function of identified candidate miRNAs. Serum specimens were collected from children with KD (n = 12) and healthy controls (n = 6). miRNA microarray assays were performed using the PANArray (TM) miRNA expression profiling kit (PANAGENE Co., Daejeon, Korea). We used TargetScan and the database for annotation, visualization, and integrated discovery program to obtain a list of enriched biological pathways targeted by miRNAs elevated in KD patients. As a result, miR-200c and miR-371-5p were significantly upregulated in the KD group compared with the control group (p = 0.032 in both). By using TargetScan, we obtained a list of 421 and 542 genes predicted to be targeted by miR-200c and miR-371, respectively, and these genes were significantly (p < 0.05) clustered in 17 and 3 pathways, respectively. Many of them are major pathways involved in inflammatory responses. The present data support the hypothesis that the inflammatory response is a crucial mechanism for pathogenesis of KD, and miRNAs might be the main regulators of this inflammatory response.