Dimerization in tailoring uptake efficacy of the HSV-1 derived membranotropic peptide gH625

Abstract

gH625 constitutes a promising delivery vehicle for the transport of therapeutic biomacromolecules across membrane barriers. We report an application of multivalency to create a complex nanosystem for delivery and to elucidate the mechanism of peptide-lipid bilayer interactions. Multivalency may offer a route to enhance gH625 cellular uptake as demonstrated by results obtained on dimers of gH625 by fluorescence spectroscopy, circular dichroism, and surface plasmon resonance. Moreover, using both phase contrast and light sheet fluorescence microscopy we were able to characterize and visualize for the first time the fusion of giant unilamellar vesicles caused by a membranotropic peptide.

Eradication of Candida albicans persister cell biofilm by the membranotropic peptide gH625

“…Peptide design. The two analogues of gH625, namely gH625-M and gH625-D, were designed exploiting the host-guest technology 34,50 . The polar features of the host peptide enables good solubility in aqueous buffer of the guest peptide and allows the peptide to remain monomeric in low ionic strength solutions.…”

“…Furthermore, the presence of four consecutive lysine residues assists the guest peptide in the binding to lipid bilayers. Briefly, we added a positively charged fragment of four lysine residues (KKKK) ( Table 1) which should favour not only the interaction with the negatively charged cell membranes, but also enhance the solubility of the mainly hydrophobic peptide gH625; moreover, the presence of the GGG or the GCG sequence allowed us to evaluate the effect of multivalency on the interaction 34 . The cysteine was exploited to form the dimer, and guarantees that both the N-terminus of the monomeric units remain free for membrane interactions, which is key because gH625 was proved to enter the bilayer from its N-terminal side 51 .…”

“…The GGG sequence was used in the monomeric peptide, the GCG for the dimeric form. Synthesis and structural characterization of gH625-M and gH625-D have been previously reported 34 .…”

Membranotropic peptides mediating viral entry

“…Several gH peptides are able to interact with membranes and play a role in the process. Among these, gH625, represents a key achievement in grasping the role of hydrophobic viral peptides . The peptide contains residues critical for interaction such as aromatic residues (tryptophan and tyrosines) which are known for their preferred location at the membrane interface and for their ability to facilitate oligomerization together with numerous hydrophobic residues (glycines, leucines, alanines) which are critical for membrane insertion; at the C‐terminus there is an arginine residue which is key for establishing peptide–lipid interactions.…”

“…On the contrary, membranotropic peptides are internalized by direct penetration of the membrane and thus determine immediate bioavailability of the delivered molecule. Fusion membranotropic peptides are particularly noteworthy because they can physically interfere with the membrane hydrophobic interior forming bulges that protrude from the membrane and ease contacts between fusing bilayers; in particular, they are able to translocate molecules through the plasma membrane directly into the cell, promoting lipid–membrane reorganizing processes, and causing local and temporary membrane destabilization with subsequent reorganization, circumventing the endosomal entrapment by favoring the escape from the endosome . The internalization mechanism is also related to the toxicity of the internalized drug and the development of resistance.…”