Cellular delivery of functional peptides to block cytokine gene expression

Advances in molecular and cellular biology have identified the cellular med iators that regulate many disease processes and have facilitated the develo pment of new therapeutic agents that control these events. However, the siz e, complexity, and cellular inaccessibility of these therapeutic agents mak e their cellular delivery difficult. Here, we describe an efficient cellula r delivery system that exploits the membrane-translocating ability of signa l peptides to import functional peptides into cells. Molecular conjugates c onsisting of the signal import peptide (IP) and nuclear localization sequen ce (NLS) of the transcription factor NF-kappa B were synthesized. Electroph oretic mobility shift and enzyme-linked immunosorbent assays were used to a ssess the inhibitory effects of these synthetic peptides on agonist-induced NF-kappa B nuclear translocation and transcriptional activation. Our resul ts indicated that the peptides were effective in inhibiting both the nuclea r translocation and transcriptional activation of NF-kappa B. However, thei r effects required the presence of the IP moiety for efficient cellular ent ry of the NLS. Structural analysis of IP show ed that the hydrophobic domai n, and to a lesser extent the N-terminal domain, was responsible for the me mbrane translocating activity of IP. (C) 2000 Elsevier Science B.V. All rig hts reserved.