Peripheral blood microRNAs expression is associated with infant respiratory syncytial virus infection

Abstract

MicroRNAs respond to the inflammatory responses induced by RNA virus infection. In this study, we investigated the specific microRNA profile in the peripheral blood of infants infected with respiratory syncytial virus (RSV). Blood specimens were analyzed using microRNA microarrays, followed by quantitative RT-PCR. A specific microRNA profile in the peripheral blood of RSV-infected infants was identified for the first time. MiR-106b-5p, miR-20b-5p, and miR-342-3p were upregulated, while miR-320e, miR-320d, miR-877-5p, miR-122-5p, and miR-92b-5p were downregulated. Pathway analysis indicated that the dysregulated microRNAs were involved in inflammatory and immune responses, including Wnt, TGF-β, insulin, and T and B cell receptor signaling. These results demonstrate that RSV infection associates with a distinct microRNA fingerprint and suggest that RSV induces inflammatory responses in infants.

Keywords: Immune response; Immunity; Immunology and Microbiology Section; infants; inflammatory response; miRNA; peripheral blood; respiratory syncytial virus.

Figure 1. RSV regulated microRNAs expression in peripheral blood

This heat figure was generated using comparison analysis based on signal value ratio method; it provides an overall picture of the impact of RSV infection on the peripheral blood miRNAs as compared to healthy control blood. Data were partitioned between RSV and control (CTL1) samples during the hierarchical clustering and organized into blocks of columns. The rows represent probe sets in each of the arrays, and within each row, the blue shaded areas indicate lower expression of the specific miRNA, whereas the yellow shaded areas indicate higher expression. Black and darkly shaded areas indicate similar expression between infected and non-infected samples. The Euclidean clustering method was used for array data analysis. The expression index is shown in the left upper corner.

Figure 2. Validation of miRNA microarray findings by quantitative qRT-PCR

Grey column represents miRNAs relative expression level of control samples (2^-ΔΔCt=1.0). Other color columns represent the selected miRNAs relative levels of each RSV infection sample. A. Relative expression of five upregulated miRNAs (miR-106b-5p, miR-181a-5p, miR-20b-5p, miR-342-3p and miR-652-3p) in microarray. B. Relative expression of six downregulated miRNAs (miR-122-5p, miR-320e, miR-320d, miR-877-5p, miR-92b-5p and let-7c-5p) in microarray. Asterisk indicates the significant differences between RSV infection and control groups (P < 0.05).

Figure 3. Common genes and relevant pathways’ crossing network of seven validated differential expression microRNAs