Background:
Lipopeptide-based gene carriers have shown low cytotoxicity, are capable
of cell membrane penetration, are easy to manufacture and therefore are great potential candidates
for gene delivery applications.
Objectives:
This study aims to explore a range of short synthetic lipopeptides, (Lau: Lauryl; Pal:
Palmitoyl) consisting of an alkyl chain, one cysteine (C), 1 to 2 histidine (H), and lysine (K) residues
by performing in-silico molecular interaction and in-vitro evaluation.
Methods:
The molecular interactions between the lipopeptides and Importin-α receptor were performed
using AutoDock Vina and Amber14. The lipopeptide/DNA complexes were evaluated in-
-vitro for their interactions, particle size, zeta potential and transgene expression. Transfection efficiency
of the lipopeptides and Pal-CKKHH-derived liposome was carried out based on luciferase
transgene expression.
Results:
The in-silico interaction showed that Lau-CKKH and Pal-CKKHH hypothetically expedited
nuclear uptake. Both lipopeptides had lower binding energy (-6.3 kcal/mol and -6.2 kcal/mol, respectively),
compared to the native ligand, viz, nuclear localization sequence (-5.4 kcal/mol). The
short lipopeptides were able to condense DNA molecules and efficiently form compacted nanoparticles.
Based on the in-vitro evaluation on COS-7, Pal-CKKHH was found to be the best transfection
agent amongst the lipopeptides. Its transfection efficiency (ng Luc/mg total protein) increased up to
~3-fold higher (1163 + 55) as it was formulated with helper lipid DOPE (1:2). The lipopeptide-
based liposome (Pal-CKKHH: DOPE=1:2) also facilitated luciferase transgene expression on
human embryonic kidney cells (293T) and human cervical adenocarcinoma cells (HeLa) with transfection
efficiency 1779 +52 and 260 + 22, respectively.
Conclusion:
Our study for the first time has shown that the fully synthesized short lipopeptide Pal-
CKKHH is able to interact firmly with the Importin-α. The lipopeptide is able to condense DNA
molecules efficiently, facilitate transgene expression, expedite the nuclear uptake process, and
hence has the characteristics of a potential transfection agent.