Plasma exosomal microRNA expression profiles in patients with high-altitude polycythemia.

High-altitude polycythemia (HAPC) is a chronic mountain sickness characterized by multiple severe ill-effects. Its pathogenesis is still unclear, and till date, no study has been conducted to investigate the plasma exome profile of Tibetan patients with HAPC. In this study, we aimed to elucidate the pathogenesis of HAPC by determining the microRNA (miRNA) signatures. We compared the plasma exosome miRNA expression profiles of eight patients with HAPC and eight healthy controls using next-generation miRNA sequencing. Further, we extracted and identified plasma exosomes using transmission electron microscopy, nanoparticle tracking analysis, and western blotting. We used quantitative reverse-transcription polymerase chain reaction (qRT-PCR) to validate differentially expressed plasma exosomal miRNAs. Finally, we analyzed the diagnostic values of the differentially expressed miRNAs for HAPC using receiver operating characteristic (ROC) curves. We detected 2007 miRNAs from confirmed plasma exosomes, including 1342 known miRNAs and 665 newly predicted miRNAs. We verified the expression of the top 10 differentially expressed miRNAs via qRT-PCR. Patients with HAPC showed significantly upregulated hsa-miR-122-5p, hsa-miR-423-5p, hsa-miR-4433b-3p, hsa-miR-1291, and hsa-miR-106b-5p expression levels, while hsa-miR-200c-3p expression was downregulated. This study may provide background knowledge for future studies on HAPC studies, which may further facilitate the development of novel therapies against this common disease.