Study of the miRNA expression profile of cholesteatoma-derived exosomes and its clinical application

Abstract

Background: Cholesteatoma is a chronic disease that is caused by the abnormal proliferation of keratinized squamous epithelial cells in the middle ear. This study aims to explore the role of exosomal miRNAs in the pathogenesis of cholesteatoma and their potential in clinical diagnosis. Methods: We collected samples of cholesteatoma and normal retroauricular skin from 14 patients and isolated exosomes from these tissues. Exosomes were identified by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and western blotting. Further miRNA sequencing was conducted to identify the unique exosomal miRNA expression pattern in cholesteatoma. The potential roles of differentially expressed miRNAs (DE-miRNAs) were investigated via Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Then, we filtered the top 9 DE-miRNAs to perform KEGG pathway enrichment analysis, and we validated the levels of these DE-miRNAs in peripheral blood plasma-derived exosomes from 12 cholesteatoma patients, 6 chronic otitis media patients and 4 healthy individuals. Results: Tissue-derived exosomes were successfully extracted from cholesteatoma and normal skin tissues. MiRNA sequencing revealed 14 upregulated miRNAs and 25 downregulated miRNAs in the cholesteatoma-derived exosomes. Bioinformatics analysis indicated that the DE-miRNAs participated in a variety of biological processes, cell components and molecular functions. The differential expression of hsa-miR-223-3p and hsa-miR-142-5p was verified in plasma-derived exosomes from cholesteatoma patients, and these molecules showed a modest ability to distinguish between cholesteatoma and normal samples (AUC=0.81 and AUC=0.84, respectively). We further identified the potential functions of these molecules in cholesteatoma pathogenesis through a KEGG pathway network. Conclusions: Our study is the first to explore the specific exosomal miRNA profile of cholesteatoma. Exosomal miR-223-3p and miR-142-5p can be considered promising biomarkers for the diagnosis of cholesteatoma.