Transcriptional and functional analysis of plasma exosomal microRNAs in acute viral myocarditis

To assess the differential expression profiles of exosome-derived microRNA (miRNA) and reveal their potential functions in patients with acute viral myocarditis (AVMC).

Peripheral blood samples were collected from 9 patients diagnosed with AVMC and 9 healthy controls (HC) in the Affiliated Hospital of Qingdao University from July 2021 to September 2022. The exosomal miRNA expression were tested using RNA high-throughput sequencing. We conducted the GO and KEGG functional analysis to predict the potential molecular, biological functions and related signaling pathways of miRNAs in exosomes. Target genes of exosomal miRNAs were predicted and miRNA-target gene network was mapped using gene databases. Differentially expressed exosomal miRNAs were selected and their expression levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR) to verify the sequencing results.

P < 0.05 and Fold Change>2 were considered as cut-off value to screen miRNAs that were differently expressed. This study identified 14 upregulated and 14 downregulated exosome-derived miRNAs. GO and KEGG analysis showed that differentially expressed miRNAs may be related to β-catenin binding, DNA transcription activities, ubiquitin ligase, PI3K-Akt, FoxO, P53, MAPK, and etc.. The target genes of differentially expressed miRNAs were predicted using gene databases. Real-time PCR confirmed the upregulation of hsa-miR-548a-3p and downregulation of hsa-miR-500b-5p in AVMC.

Hsa-miR-548a-3p and hsa-miR-500b-5p could serve as a promising biomarker of AVMC. Exosomal miRNAs may have substantial roles in the mechanisms of AVMC.