Aim of the study: To delineate the underlying mechanism of microRNA-145 modulate the balance of Th1/Th2 via targeting RUNX3 in asthma patients.
Materials and methods: Peripheral blood samples were collected from asthma patients and healthy controls. CD4+ T cells were isolated and cultured. Using quantitative PCR detect, the level of microRNA-145 and RUNX3 mRNA level in the CD4+ T cells from asthma patients and healthy controls, meanwhile, western blot was used to detect the RUNX3 protein level. Th1 or Th2 related cytokines were measured by enzyme-linked immunosorbent assay. Dual-Luciferase Reporter Assay was performed to confirm the correlation between microRNA-145 and RUNX3. MicroRNA-145 mimic or inhibitor was transfected in the CD4+ T cells and the changes of RUNX3 level, Th1 or Th2 related cytokines and the percentage of Th1 and Th2 were observed after transfection.
Results: MicroRNA-145 level of CD4+ T cells was higher with a lower RUNX3 expression in asthma patients. There is negative correlation between microRNA-145 and RUNX3. Th2 hyperactivity and Th1 deficiency was detected in the CD4+ T cells of asthma patients. Dual-Luciferase Reporter Assay has shown that RUNX3 is a target of microRNA. Up-regulation or down-regulation of miR-145 level caused RUNX3 expression changes in CD4+ T cells and influence the related cytokines. Inhibition of microRNA-145 may reverse the imbalance of Th1/Th2 in asthma patients.
Conclusion: MicroRNA-145 could regulate the balance of Th1/Th2 through targeting the RUNX3 in asthma patients. MicroRNA-145 and RUNX3 may be used as biomarkers or targets in the diagnosis or therapy of asthma.
Keywords: RUNX3; T cells; asthma; microRNA.