Cell permeable NFAT inhibitory peptide Sim-2-VIVIT inhibits T-cell activation and alleviates allergic airway inflammation and hyper-responsiveness.

Nuclear factor of activated T cells (NFAT) is an important transcription factor for the production of interleukin (IL)-2 upon T-cell receptor (TcR) signaling. Therefore, inhibition of the NFAT-carcineurin pathway is an important target for inflammatory disease inhibition and graft rejection. A novel cell permeable peptide (CPP), Sim-2, has been identified from a human transcription factor, and Sim-2-CPP conjugated to β-galactosidase or EGFP protein was efficiently delivered into cells in vitro and in vivo. A cell permeable form of the NFAT inhibitory peptide VIVIT (Sim-2-VIVIT) was synthesized and showed inhibitory effects on human CD4 or CD8 T-cell activation through NFAT transcriptional activity suppression and IL-2 inhibition. Intranasal administration of the Sim-2-VIVIT peptide in an ovalbumin (OVA)-induced murine asthma model alleviated peribronchial and perivascular infiltration of inflammatory cells in the lung and caused airway remodeling and airway hyper-responsiveness. These results suggest that cell permeable Sim-2-VIVIT peptide has clinical potential as an immunosuppressive agent for inflammatory diseases.