Prevention of NF-κB activation in vivo by a cell-permeable NF-κB inhibitor peptide

Abstract

The NF-κB/Rel transcription factor family plays a central role in coordinating the expression of a variety of genes that regulate stress responses, immune cell activation, apoptosis, proliferation, differentiation, and oncogenic transformation. Interventions that target the NF-κB pathway may be therapeutic for a variety of pathologies, especially immune/inflammatory diseases. Using membrane translocating sequence (MTS) technology, we developed a cell-permeable dominant inhibitor of NF-κB activation, termed IκBα-(ΔN)-MTS. This molecule contains a 12-amino acid MTS motif attached to the COOH-terminal region of a nondegradable inhibitor protein [IκBα-(ΔN)]. The recombinant protein enters cells and localizes in the cytoplasm. Delivery of the IκBα-(ΔN)-MTS to cell lines and primary cells inhibited nuclear translocation of NF-κB proteins induced by cell activation. The protein also effectively inhibited NF-κB activation in vivo in two different animal models: NF-κB activation in response to skin wounding in mice and NF-κB activation in lungs after endotoxin treatment in sheep. Inhibition of NF-κB by the IκBα-(ΔN)-MTS in the endotoxin model attenuated physiological responses to endotoxemia. These data demonstrate that activation of NF-κB can be inhibited using a recombinant protein designed to penetrate into cells. This technology may provide a new approach to NF-κB pathway-targeted therapies.