Conversion of cationic amphiphilic lytic peptides to cell‐penetration peptides

Abstract

AbstractAccomplishment of efficient intracellular delivery of bioactive peptides and proteins have been reported via conjugation of peptides having membrane permeation ability (i.e., cell‐penetrating peptides [CPPs]), where a physiological uptake system of extracellular materials, endocytosis, often plays a role. When endocytosed, the bioactive peptides and proteins are encapsulated into vesicular compartment named endosomes, and have to escape into the cytosol with the help of tethered CPPs for obtaining the expected bioactivities. Therefore, CPPs having improved endosomolytic activity is necessary. We here introduce an approach to employ hemolytic peptides as a new class of CPPs, which was designed to attenuate their membrane perturbation ability on cell surfaces while recovering the membrane lytic activity under endosomal conditions (i.e., the attenuated cationic amphiphilic lytic [ACAL] peptides). This was realized by introducing negatively charged glutamic acid (Glu) residues into the potential hydrophobic face of the cationic amphiphilic peptides. The applicability of these peptides for CPPs was evaluated through the intracellular delivery of shepherdin, an apoptosis‐inducing peptide.