Potentiating the Membrane Interaction of an Attenuated Cationic Amphiphilic Lytic Peptide for Intracellular Protein Delivery by Anchoring with Pyrene Moiety.

We previously reported an approach for intracellular protein delivery by attenuating membrane-lytic activity of cationic amphiphilic peptides on cell surfaces. HAad is one such peptides that cytosolically delivers proteins of interest, including antibodies, by stimulating their endosomal escape. Additionally, HAad elicits ruffling of cell membrane, accompanied by transient membrane permeabilization, allowing for the efficient cytosolic translocation of proteins. In this study, we prepared a conjugate of HAad with pyrenebutyric acid as a membrane-anchoring unit (pBu-HAad). pBu-HAad demonstrated protein delivery into cells with only 1/20 concentration of HAad. However, the conjugates with cholesteryl hemisuccinate and aliphatic fatty acids (C = 3, 6, and 10) did not yield such marked effects. The results of time-course and inhibitor studies suggest that the membrane anchoring of HAad by a pyrene moiety leads to enhanced peptide-membrane interaction and to loosen lipid packing, thus facilitating cytosolic translocation through membranes.