LAUSR

HighlightsThe expression of miR‐144 was decreased in the matured DCs, macrophages, and PBMCs.MiR‐144 mimics inhibit TNF‐&agr;, IL‐1&bgr;, IL‐6 and IL‐23 in DCs, and IL‐17 in Th17 cells.MiR‐144 exerted its immune regulation effect by interacting with RANKL. Abstract To investigate whether the microRNA‐144 (miR‐144) had immune regulation effect on matured immune cells, we firstly used quantitative RT‐PCR (qRT‐PCR) to detect the expression changes of miR‐144 between the matured and immature dendritic cells (DCs), macrophages, and the peripheral blood mononuclear cells (PBMCs). Then we went on inspecting the expression changes of TNF‐&agr;, IL‐1&bgr;, IL‐6 and IL‐23 in the matured DCs treated with miR‐144 mimics or inhibitors using qRT‐PCR, and also performed western blot to test phosphorylation state of ERK, JNK, p38 and p65 in these cells. Next, TargetScan was conducted to forecast the target gene of miR‐144, receptor activator for nuclear factor‐&kgr;B ligand (RANKL), and double luciferase reporter system was applied to research their banding sites. We also determined the expression changes of RANKL in the DCs treated with miR‐144 mimics or inhibitors using qRT‐PCR and ELISA, respectively. The siRNA of RANKL was synthesized and transfected into DCs to inspect how the immune regulation effect of miR‐144 was conducted to inhibit the expression of TNF‐&agr; using qRT‐PCR, and lastly we used flow cytometry to investigate whether this effect applied to Th17 cells. As results, we found that miR‐144 was down‐regulated in the matured DCs, macrophages and PBMCs of liver transplantation patients, and the miR‐144 mimics could inhibit the expression levels of TNF‐&agr;, IL‐1&bgr;, IL‐6 and IL‐23 in the matured DCs. Furthermore, miR‐144 interacted with RANKL at position 679–685 of RANKL 3′UTR, and suppressed the translation of RANKL mRNA to realize the negative‐regulation. Besides, the silence of RANKL enhanced the suppression effect of miR‐144 on TNF‐&agr; and this immune regulation effect was applied to Th17 cells, too. In conclusion, this study clearly illustrated that miR‐144 could inhibit the expression of cytokine in matured immune cells through suppressing the translation of RANKL mRNA.