Plasma exosomal miRNA profiles in pediatric fulminant myocarditis patients and healthy controls

The pathophysiology of fulminant myocarditis (FM) is significantly influenced by the interactions between immunological and myocardial cells, involving exosome-mediated intercellular microRNA (miRNA) signaling. To further investigate the pathogenesis of FM and discover diagnostic biomarkers, we have employed miRNA microarray expression profiling as a discovery platform. Plasma exosome miRNAs of 3 pediatric FM patients and 3 healthy volunteers were analyzed using a small RNA microarray analysis. The pathophysiological relevance and potentials as diagnostic biomarkers of the most significantly altered miRNAs were explored. To screen for FM-specific target genes, differentially expressed mRNAs in peripheral blood mononuclear cells (PBMCs) from pediatric FM patients were intersected with the miRNA target genes obtained from 5 different miRNA target gene predictive tools. The hub genes and their biological and mechanistic pathways related to inflammation and/or the immune system were identified. CeRNA networks of lncRNAs, circRNAs, miRNAs, and mRNAs between cardiomyocytes and PBMCs were finally established. Furthermore, we verified that the expression levels of four selected miRNAs were increased in plasma exosomes of pediatric FM patients compared to those in controls by qRT-PCR.