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 plays a vital role in TCR signalling by mediating T-cell activation. Abnormal CD3 expression is a common characteristic of haematological malignancies with T-cell immune dysfunction or autoimmune diseases. Targeted regulation of CD3 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 expression.

Material and methods
Three microRNA target search algorithms (TargetScan, PicTar, and microrna.org) were used to identify hypothetical miRNAs that target CD3 in T cells. Of the predicted miRNAs, miR-214 was chosen and validated to determine whether miR-214 directly binds to the CD3 3’-UTR and regulates CD3 expression by luciferase reporter assays, real-time PCR, and Western blotting.

Results
The results indicate that miR-214 specifically binds the CD3 3’-UTR, and miR-214 mimics remarkably reduce the expression of CD3 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.