ABSTRACT
Objective:To investigate the function of miR-5581-5p and its interaction with tripartite motif 22 (TRIM22) during the terminal differentiation of human acute promyelocytic leukemia (APL) cells into granulocytes.Methods:APL cells (NB4) were differentiated into granulocytes by all-trans retinoic acid (ATRA), using dimethylsulfoxide (DMSO) as the control. The expression of TRIM22 was detected by real-time fluorescent quantitative PCR (qRT-PCR) and Western blotting, and the expression of miR-5581-5p was detected by qRT-PCR during cell differentiation. miRNA expression was regulated by cell transfection with miR-5581-5p mimic and inhibitor, and negative control was set, and qRT-PCR was used to verify the regulatory effect. Luciferase binding assay was performed to detect the presence of targeted binding. Western blotting was used to detect the expression of TRIM22 after miRNA differential expression. Flow cytometry was used to detect the effects of the regulation of miR-5581-5p on the differentiation of NB4 cells induced by ATRA.Results:After ATRA induced NB4 cells to differentiate into granulocytes, the gene expression level of TRIM22 was significantly higher than that of the control group (24.56±2.80 vs. 1.02±0.13; t=8.392, P=0.001). The level of protein expression was also significantly higher than that of the control group (0.80±0.01 vs. 0.17±0.01; t=44.900, P<0.001). The expression level of miR-5581-5p in NB4 cells differentiation group was significantly lower than that in the control group (0.14±0.02 vs. 1.01±0.08; t=10.840, P<0.001). The results of the dual luciferase reporter gene showed that the luciferase activity of the co-transfected miR-5581-5p mimic and TRIM22 WT group was significantly lower than that of the co-transfected miR-5581-5p mimic and TRIM22 MUT group (0.73±0.02 vs. 0.98±0.03; t=7.534, P=0.002). Western blotting showed that after transfection with miR-5581-5p inhibitor, the expression of TRIM22 was significantly higher than that of the negative control (0.44±0.01 vs. 0.21±0.01; t=18.290, P<0.001). While after transfection with miR-5581-5p mimic, the expression of TRIM22 decreased significantly compared with the negative control (0.62±0.01 vs. 0.80±0.02; t=6.402, P=0.003). CD11b expression of miR-5581-5p mimic group after ATRA treatment was significantly lower than that of the control group (45.80±1.80 vs. 56.61±1.88; t=4.159, P=0.014). The expression of CD11b in miR-5581-5p inhibitor group was significantly higher than that in the control group (66.48±2.54 vs. 52.60±1.70; t=4.539, P=0.011). Conclusion:miRNA-5581-5p can bind to TRIM22 3′UTR and negatively regulate TRIM22 expression. The decrease of miR-5581-5p can increase the expression of TRIM22, then promote the differentiation of ATRA-induced NB4 cells into granulocytes.