MiR-214 regulates CD3ζ expression in T cells.

Introduction: T-cell activation requires the T-cell receptor (TCR)-CD3 complex, which integrates and transduces signals. CD3 zeta plays a vital role in TCR signalling by mediating T-cell activation. Abnormal CD3 zeta expression is a common characteristic of haematological malignancies with T-cell immune dysfunction or autoimmune diseases. Targeted regulation of CD3 zeta expression by either direct or indirect approaches is important for regulating T-cell activation. Aim of the study: In this study, we focused on identifying miRNAs that may regulate CD3 zeta expression. Material and methods: Three microRNA target search algorithms (TargetScan, PicTar, and micro-rna.org) were used to identify hypothetical miRNAs that target CD3 zeta in T cells. Of the predicted miRNAs, miR-214 was chosen and validated to determine whether miR-214 directly binds to the CD3 zeta 3'-UTR and regulates CD3 zeta expression by luciferase reporter assays, real-time PCR, and Western blotting. Results: The results indicate that miR-214 specifically binds the CD3 zeta 3'-UTR, and miR-214 mimics remarkably reduce the expression of CD3 zeta in MOLT-4 cells. Conclusions: We identify for the first time that miR-214 targets expression in MOLT-4 cells, suggesting that miR-214 might negatively regulate T-cell activation by targeting CD3 zeta.