OBJECTIVETo study differential expression of microRNA (miRNA) in peripheral blood mononuclear cells (PBMNC) from patients with different types of aplastic anemia (AA) and explore the role of miRNA in the pathogenesis of AA.

METHODSmiRNA microarray were used to determine the differential expression profile of miRNA in PBMNC from patients with AA. Real-time quantitative polymerase china reaction (RQ-PCR) was used to verify the differential expression of miRNA. Candidate miRNA were analyzed with bioinformatics tools.

RESULTSCompared with the normal controls, 6 miRNAs were up-regulated and 10 were down-regulated in patients with severe aplastic anemia (SAA), while 24 miRNAs were up-regulated and 12 were down-regulated in patients with chronic non-severe aplastic anemia (CAA). Compared with CAA patients, 4 miRNAs were up-regulated and 11 were down-regulated in SAA patients. Compared with normal controls, 3 miRNAs were up-regulated and 4 were down-regulated in both SAA and CAA patients. As verified by RQ-PCR, expression of miR-155-5p and miR-1260b were increased in both CAA and SAA patients compared with the normal controls (P<0.01). The expression of miR-155-5p and miR-1260b of CAA patients were higher than that of SAA patients (P<0.01). Bioinformatics analysis showed that target genes of miR-155-5p and miR-1260b may be involved in regulation of cell metabolism, gene expression and transcription, TNF signaling pathway, B cell receptor signaling pathway, Fc gamma R-mediated phagocytosis and other signaling process.

CONCLUSIONThere are characteristic differential expression profiles of miRNA in PBMNC from CAA and SAA patients, in which miRNA-155-5p and miRNA-1260b are both up-regulated. The common target gene predicted for miRNA-155-5p and miRNA-1260b is ETS1. miRNA-155-5p and miRNA-1260b may act synergistically to inhibit the expression of ETS1 and promote differentiation of Th17, therefore play an important role in the pathogenesis of AA.