Spacer Length: A Determining Factor in the Design of Galactosyl Ligands for Hepatoma Cell-Specific Liposomal Gene Delivery

Author(s): Londiwe Mbatha, Santanu Chakravorty, Charles B. de Koning, Willem A.L. van Otterlo, Patrick Arbuthnot, Mario Ariatti, Moganavelli Singh.

Journal Name: Current Drug Delivery

Volume 13 , Issue 6 , 2016

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Graphical Abstract:


Background: Use of nucleic acids to treat acquired or inherited hepatic diseases has considerable potential. Although recombinant viruses are popular vectors, interest in cheaper, often less immunogenic, non-viral modalities, is increasing. Thus hepatotropic, galactosylated lipoplexes directed to the hepatic asialoglycoprotein receptor (ASGP-R) are promising candidates.

Objective: Here we examine the effect that galactosyl ligand spacer length has on the transfection activity of ASGP-Rtargeted lipoplexes in the human hepatoma cell line HepG2.

Methods: Galactosyl ligands with spacer lengths in the range 2.4-24.1 Å were prepared and formulated into lipoplexes that were characterized by cryo-TEM, band shift, dye displacement and nuclease digestion assays. Cytotoxicity and transfection profiles were determined in liver-derived HepG2 cells and the renal ASGP-R-negative HEK293 line.

Results: Lipoplexes, which formed at endpoint +/- charge ratios in the range 1:1-3:1, accorded cargo DNA good protection from serum nuclease digestion and were well-tolerated by both cell lines. Transfection activities in the hepatoma cell line decreased markedly in the presence of a competing ASGP-R cognate ligand and also as the ligand spacer length increased, while activities in HEK293 cells were significantly lower (P <0.05-0.001).

Conclusion: Targeted lipoplexes enter HepG2 cells by receptor mediation and the uptake of transfecting complexes and those displaying more rigid short and medium length spacers is more efficient. This observation will inform the design of hepatotropic lipoplexes that are suitable for applications in vivo.

Keywords: DNA lipoplexes, galactosylated liposomes, hepatocyte-specific, hepatoma cell line, non-viral gene delivery, spacer length.

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Article Details

Year: 2016
Page: [935 - 945]
Pages: 11
DOI: 10.2174/1567201813666160224123450
Price: $58

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