Cell-Penetrating Peptides With Antimicrobial, Transfection And Transduction Activities

A family of histidine-rich peptides LAH4 was designed using linear cationic peptides such as magainins as a template. These designed peptides have been shown to exhibit considerable antimicrobial, nucleic acid transfection as well as cell penetrating activities. In contrast to their natural templates their membrane interactions are strongly pH dependent. The delivery of cargo by these peptides is complex, involving many steps, which we investigated on a structural and biophysical level. Recently, vectofusin-1, a member of the family of LAH4 peptides has been shown to spontaneously self-assemble into helical coiled-coil structures, spherical aggregates, that further assemble into annular and extended nanofibrils and hydrogels as a function of phosphate and in a pH-dependent manner. This bears considerable interest for the design of biomaterials. Furthermore, the peptide has a strong capacity to enhance the gene transfer by lenti- and adeno associated viruses into the cell interior. Thereby, the fibers formed by this short peptide have gene therapeutic applications ranging from monogenic and infectious diseases to cancer, by enhancing transduction levels of target cells and reducing the amount of lentivirus for greater safety and reduced costs. Vectofusin-1 promotes the entry of several retroviral pseudotypes into target cells when added to the culture medium, without cytotoxicity. These associate with viral particles allowing them to be easily pelleted. These fibrils have a unique coiled-coil α-helical structure whereas most other viral transduction enhancers form β-amyloid fibrils. Our observations define vectofusin-1 as a member of a new class of α-helical lentiviral transduction enhancers. Its coiled-coil fibril formation is reversible which bears considerable advantages in handling the peptide in conditions well-adapted to scalable gene therapy protocols. References: J PepSci 21, 346 (2015), JPC B 119, 9678 (2015), JBC 291, 2161 (2016), Acta Biomat (2017 in press), SciRep 7:9585 (2017).