Proteomic analysis and microRNA expression profiling of plasma-derived exosomes in primary immune thrombocytopenia

Exosomes are released into extracellular fluids and have emerged as vital biological mediators in autoimmune diseases. Plasma-derived exosomes have been reported to take part in the pathogenesis of primary immune thrombocytopenia (ITP), but the protein and miRNA cargoes have not been entirely elucidated. Via proteomic analysis and RNA sequencing on plasma-derived exosomes from ITP patients and healthy controls, we found one upregulated exosomal protein (apolipoprotein E, ApoE), six downregulated exosomal miRNAs (miR-584-5p, miR-4433a-5p, miR-4433b-3p, miR-6842-3p, miR-130b-5p and miR-222-3p), and 10 upregulated exosomal miRNAs (miR-29a-3p, miR-142-5p, miR-16-2-3p, miR-29b-3p, miR-501-3p, miR-144-5p, miR-192-5p, miR-182-5p, miR-363-3p and miR-96-5p) in ITP patients. The elevated exosomal protein candidate ApoE in the ITP cohort was further validated using western blot. Via quantitative real-time polymerase chain reaction assays, three differentially expressed miRNAs (miR-584-5p, miR-142-5p and miR-29b-3p) were identified. This study provides direct evidence for a restricted signature of exosomal protein and miRNAs which distinguishes ITP from healthy controls. The results require further validation in larger independent ITP cohorts, which will provide insights into the potential pathophysiological significance of circulating exosomes in ITP.