Effect of cell membrane thiols and reduction-triggered disassembly on transfection activity of bioreducible polyplexes

Abstract

Bioreducible polyplexes are promising vectors for delivery of nucleic acids due to low toxicity and favorable transfection activity. The often improved transfection is usually explained by enhanced intracellular reductive disassembly of the polyplexes. This study evaluated the effect of enhanced reductive disassembly on transfection activity of plasmid DNA and antisense oligonucleotide (AON) polyplexes based on a series of bioreducible poly(amido amine)s (PAA). We found that the presence of disulfide bonds in PAA had no effect on nucleic acid binding, hydrodynamic size and zeta potential of polyplexes. Increasing the disulfide content in PAA increased susceptibility to reduction-triggered DNA and AON release from the polyplexes. Increasing the disulfide content in PAA increased DNA transfection but had no effect on AON transfection. Plasma membrane protein thiols played a key role in the observed enhancement of DNA transfection. The presence of disulfide bonds in PAA had no significant effect on the rate of intracellular DNA clearance, suggesting that enhanced intracellular disassembly of the bioreducible polyplexes is not a major contributing factor to the improved transfection activity.

Effect of biodegradability on CXCR4 antagonism, transfection efficacy and antimetastatic activity of polymeric Plerixafor

“…Intracellular degradation of the reducible polycations not only contributes to efficient disassembly of the polyplexes, but also to better spatial selectivity of release of the nucleic acids in the cytoplasm and to decreased cytotoxicity. Furthermore, the interactions between the reducible polyplexes and cell surface thiols are also playing an important role in improving cellular uptake of reducible polyplexes [15]. …”

The yin of exofacial protein sulfhydryls and the yang of intracellular glutathione in in vitro transfection with SS14 bioreducible lipoplexes

“…Moreover, we speculate that this behavior is specific for bioreducible lipoplexes. Nonetheless, it is worth noting that the outcome of the reduction process mediated by EPTs is likely to be determined by numerous factors including the site of disulfide introduction within the gene transfer vector [9,47], the type of non-viral vehicle used [13,49], the dose of complexes delivered to cells [23] as well as the concentration and the site where the reducing species reside [6][7][8][9].…”

Guanidinylated bioresponsive poly(amido amine)s designed for intranuclear gene delivery

“…Li et al 14 reported that 0.75 M NaCl in HBS was indispensable for pDNA release. Incubation with 20 mM GSH resulted in the dissociation of the complexes (CAR/CHL-CBA) and a release of pDNA at N/P ratios from 1/6 to 1/48.…”

“…However, PEGylated SS-PAAs also showed lower transfection efficiency than SS-PAAs. Salmaso et al 17 and Li et al 14 investigated the effect of cell membrane thiols and reduction-triggered disassembly on the transfection activity of bioreducible polyplexes, which revealed that the plasma membrane protein thiols played a key role in the observed enhancement of DNA transfection.…”