Molecular Interaction of Short Synthetic Lipopeptide/Importin-alpha and Evaluation of Transgene Expression Mediated by Liposome- Based Gene Carrier.

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.