1 research outputs found
Engineering the Aromaticity of Cationic Helical Polypeptides toward āSelf-Activatedā DNA/siRNA Delivery
The development of
potent yet nontoxic membrane-penetrating materials is in high demand
for effective intracellular gene delivery. We have recently developed
Ī±-helical polypeptides which afford potent membrane activities
to facilitate intracellular DNA delivery via both endocytosis and
the nonendocytic āpore formationā mechanism. Endocytosis
will cause endosomal entrapment of the DNA cargo, while excessive
āpore formationā would cause appreciable cytotoxicity.
Additionally, helical polypeptides with stiff, rodlike structure suffer
from low siRNA binding affinity. To address such critical issues,
we herein incorporated various aromatic domains (benzyl, naphthyl,
biphenyl, anthryl, and pyrenyl) into the side-chain terminals of guanidine-rich,
helical polypeptides, wherein the flat-rigid shape, Ļ-electronic
structures of aromatic motifs āself-activatedā the membrane-penetrating
capabilities of polypeptides to promote intracellular gene delivery.
Benzyl (Bn)- and naphthyl (Naph)-modified polypeptides demonstrated
the highest DNA uptake level that outperformed the unmodified polypeptide,
P2, by ā¼4 fold. More importantly, compared with P2, Bn- and
Naph-modified polypeptides allowed more DNA cargos to be internalized
via the nonendocytic pathway, which significantly bypassed the endosomal
entrapment and accordingly enhanced the transfection efficiency by
up to 42 fold, outperforming PEI 25k as the commercial reagent by
3ā4 orders of magnitude. The aromatic modification also improved
the siRNA condensation capability of polypeptides, achieving notably
enhanced gene-silencing efficiency against tumor necrosis factor-Ī±
to treat acute hepatic inflammation. Furthermore, we revealed that
aromaticity-augmented membrane activity was accompanied by comparable
or even significantly reduced āpore formationā capability,
thus leading to diminished cytotoxicity at high concentrations. This
study therefore provides a promising approach to manipulate the membrane
activities and penetration mechanisms of polycations, which overcomes
the multiple critical barriers preventing effective and safe gene
delivery