Serum MicroRNA Expression Profiling in Mice Infected with Rabies Virus

OBJECTIVES: Serum or plasma microRNAs (miRNAs) are potential biomarkers for the diagnosis for cancer and prenatal diseases. This study was conducted to investigate whether rabies virus causes a change in serum miRNA expression. METHODS: ICR mice were intramuscularly inoculated with rabies virus and were sacrificed weekly to collect serum and brain tissue for 4 weeks postinoculation. Mice were assigned to four groups based on the results of indirect immunofluorescent assays, enzyme-linked immunosorbent assay, and nested reverse transcription-polymerase chain reaction and the expression profiles of serum miRNAs were compared using a commercial mouse miRNA expression profiling assay. RESULTS: The expression levels of miRNAs changed significantly with the different stages of the disease. The expression level of 94 serum miRNAs in infected mice changed at least twofold. Seven microRNAs of them were significantly upregulated or downregulated in all infected mice regardless of disease status. The number of miRNAs with an expression level change decreased with the progression of the disease. In a hierarchical cluster analysis, infected mice clustered into a group separate from uninfected control mice. CONCLUSIONS: Based on the relationship of miRNAs to gene expression regulation, miRNAs may be candidates for the study of viral pathogenesis and could have potential as biomarkers.