Altered expression of miR-92a correlates with Th17 cell frequency in patients with primary biliary cirrhosis

MicroRNAs (miRNAs or miRs) are small, non-coding RNA molecules that play significant roles in numerous diseases. However, there is limited information regarding the plasma expression of miRNAs in patients with primary biliary cirrhosis (PBC) as well as the potential role of miRNAs in the development of PBC. miRNA microarray analysis was performed using plasma obtaind from three patients with PBC and three healthy controls. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to confirm the differential expression of miRNAs in the plasma and peripheral blood mononuclear cells (PBMCs) isolated from 20 patients with PBC, 20 patients with chronic hepatitis B (CHB) and 20 healthy controls. These miRNAs in PBMCs and plasma were validated by linear regression analyses. The T cell subset frequency was analyzed by flow cytometry. Correlations between altered miRNA expression and the frequency of the T cell subsets were determined by linear regression analyses. The co-expression of miRNAs and IL-17A was examined using fluorescence in situ hybridization (FISH) and immunohistochemistry. The microarray analysis identified sixteen miRNAs that were differentially expressed. Four miRNAs were validated by RT-qPCR. The expression pattern of miR-572 and miR-92a in the PBMCs correlated with the expression pattern in plasma. We also found that miR-92a expression closely correlated with the frequency of a subset of IL-17-producing T helper cells (Th17), and that miR-92a was co-expressed with IL-17A in patients with PBC. Taken together, these findings revealed that plasma from patients with PBC has a unique miRNA expression profile. Moreover, miR-92a may play an important role in the pathogenesis of PBC by regulating Th17 cell differentiation.