RESUMO
To investigate the effect and mechanism of miR-498 on Th17 cell differentiation of peripheral blood mononuclear cells (PMBCs) in rheumatoid arthritis (RA) patients, peripheral blood samples were collected from RA patients and healthy controls, respectively. The proportion of CD4IL-17 T cells (Th17 cells) or CD4FOXP3 T cells (Tregs) in T cells and the Th17/Treg ratio were identified by the flow cytometer. The STAT3 and miR-498 expression were measured by Western blot and real-time PCR, respectively. ELISA was used to detect IL-17 concentrations. Luciferase assay was performed to confirm that miR-498 directly targeted the 3' untranslated region (3'UTR) of STAT3 in CD4 T cells. The effect of miR-498 on Th17 cell differentiation was explored by transfection of miR-498 mimic and/or pcDNA-STAT3 into CD4 T cells. In PMBCs of RA patients, the Th17/CD4 T cell ratio was significantly increased, while the Tregs/CD4 T cell ratio was obviously decreased, leading to a higher Th17/Treg ratio. The results showed a reduced miR-498 expression and an increased STAT3 protein expression in PMBCs, and an increased IL-17 concentration in serum of RA patients. In cells transfected with wild-type-STAT3-LU, miR-498 mimic significantly reduced the luciferase activity, STAT3 gene and protein expression, and miR-498 inhibitor had an opposite function. While the miR-498 mimic/inhibitor had no effect on the luciferase activity and STAT3 expression in cells transfected with mutant-STAT3-LU. CD4 T cells transfected with miR-498 mimic had a lower Th17/CD4 T cell ratio and IL-17 concentration, however, transfection of pcDNA-STAT3 reversed the effect of miR-498 mimic on Th17/CD4 T cell ratio and IL-17 concentration. These results suggest that overexpression of miR-498 suppresses Th17 cell differentiation by targeting STAT3 in RA patients.
RESUMO
<p><b>OBJECTIVE</b>To investigate the effect and mechanism of miR-15a on the induction of apoptosis in breast cancer cells.</p><p><b>METHODS</b>To detect the expression level of miR-15a in breast cancer cell line MCF-7 cells and human mammary gland epithelial cell line MCF-10A cells by quantitative PCR. The target point of MCF-7 was predicted by software and was validated by luciferase report gene system. MiR-15a was transfected into MCF-7 cells with liposomes. The expression of Bcl-2 in MCF-7 cells was detected by Western blotting and the apoptosis rate of MCF-7 cells was detected by flow cytometry.</p><p><b>RESULTS</b>The expression level of miR-15a in MCF-7 cells was lower than that in the MCF-10A cells (0.253:1, P < 0.0001). The expression of MiR-15a was significantly inhibited by Bcl-2 (P < 0.05). Compared with the control, Bcl-2 expression was significantly decreased in the MCF-7 cells. The results of flow cytometry showed that the apoptosis rate was 13.4% in non-transfected MCF-7 cells, 15.9% in MCF-7 cells transfected with control RNA, and 31.5% in MCF-7 cells transfected with miR-15a (P < 0.05), indicating an evident induction of apoptosis in the MCF-7 cells.</p><p><b>CONCLUSION</b>miR-15a may have a potential application value in breast carcinoma biotherapy.</p>