lipofectamine and stearic-acid

Cationic polymers have been accepted as effective nonviral vectors for gene delivery with low immunogenicity unlike viral vectors. However, the lack of organ or cell specificity sometimes hampers their application and the modification of polymeric vectors has also shown successful improvements in achieving cell-specific targeting delivery and in promoting intracellular gene transfer efficiency.. A folic acid-conjugated stearic acid-grafted chitosan (FA-CS-SA) micelle, synthesized by a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-coupling reaction, was designed for specific receptor-mediated gene delivery.. Due to the cationic properties of chitosan, the micelles could compact the plasmid DNA (pDNA) to form micelle/pDNA complexes nanoparticles. The particle size and zeta potential of the FA-CS-SA/pDNA complexes with different N/P ratios were 100-200 nm and -20 to -10 mV, respectively. The DNase I protection assay indicated that the complexes can efficiently protect condensed DNA from enzymatic degradation by DNase I. A cytotoxicity study indicated that the micelles exhibited less toxicity in comparison with Lipofectamine™ 2000. Using SKOV3 and A549 as model tumor cells, the cellular uptake of micelles was investigated.. It was found that cellular uptake of FA-CS-SA in SKOV3 cells with higher folate receptor expression was faster than that in A549 cells with a short incubation time. Luciferase assay and green fluorescent protein detection were used to confirm that FA-CS-SA could be an effective gene vector. Transfection efficiency of the FA-CS-SA/pDNA complexes in SKOV3 cells was enhanced up to 2.3-fold compared with that of the CS-SA/pDNA complexes. However, there was no significant difference between the transfection efficiencies of the two complexes in A549 cells. Importantly, the transfection efficiency of FA-CS-SA/pDNA decreased with free FA pretreatment in SKOV3 cells. It was concluded that the increase in transfection efficiency of the FA-CS-SA/pDNA complexes was attributed to folate receptor-mediated endocytosis.

Topics: Cell Line, Tumor; Cell Survival; Chitosan; Deoxyribonuclease I; Electrophoretic Mobility Shift Assay; Folate Receptors, GPI-Anchored; Folic Acid; Green Fluorescent Proteins; Humans; Lipids; Micelles; Microscopy, Fluorescence; Particle Size; Plasmids; Recombinant Proteins; Static Electricity; Stearic Acids; Transfection

In recent years, oligonucleotide-based molecules have been intensely used to modulate gene expression. All these molecules share the common feature of being essentially impermeable over cellular membranes and they therefore require efficient delivery vectors. Cell-penetrating peptides are a group of delivery peptides that has been readily used for nucleic acid delivery. In particular, polyarginine and derivates thereof, i.e. the (RxR)(4) peptide, have been applied with success both in vitro and in vivo. A major problem, however, with these arginine-rich peptides is that they frequently remain trapped in endosomal compartments following internalization. The activity of polyarginine has previously been improved by conjugation to a stearyl moiety. Therefore, we sought to investigate what impact such modification would have on the pre-clinically used (RxR)(4) peptide for non-covalent delivery of plasmids and splice-correcting oligonucleotides (SCOs) and compare it with stearylated Arg9 and Lipofectamine 2000. We show that stearyl-(RxR)(4) mediates efficient plasmid transfections in several cell lines and the expression levels are significantly higher than when using unmodified (RxR)(4) or stearylated Arg9. Although the transfection efficiency is lower than with Lipofectamine 2000, we show that stearyl-(RxR)(4) is substantially less toxic. Furthermore, using a functional splice-correction assay, we show that stearyl-(RxR)(4) complexed with 2'-OMe SCOs promotes significant splice correction whereas stearyl-Arg9 fails to do so. Moreover, stearyl-(RxR)(4) promotes dose-dependent splice correction in parity with (RxR)(4)-PMO covalent conjugates, but at least 10-times lower concentration. These features make this stearic acid modified analog of (RxR)(4) an intriguing vector for future in vivo experiments.

Topics: Alternative Splicing; Animals; Cell Membrane Permeability; Cell Proliferation; CHO Cells; Cricetinae; Cricetulus; Drug Carriers; Flow Cytometry; Gene Expression; HeLa Cells; Humans; Lipids; Luciferases; Nucleic Acids; Peptides; Phosphorothioate Oligonucleotides; Plasmids; Stearic Acids; Transfection

Aberrations in splicing patterns play a significant role in several diseases, and splice correction, together with other forms of gene regulation, is consequently an emerging therapeutic target. In order to achieve successful oligonucleotide transfection, efficient delivery vectors are generally necessary. In this study we present one such vector, the chemically modified cell-penetrating peptide (CPP) TP10, for efficient delivery of a splice-correcting 2'-OMe RNA oligonucleotide. Utilizing a functional splice correction assay, we assessed the transfection efficiency of non-covalent complexes of oligonucleotides and stearylated or cysteamidated CPPs. Stearylation of the CPPs Arg9 and penetratin, as well as cysteamidation of MPG and TP10, did not improve transfection, whereas the presence of an N-terminal stearyl group on TP10 improved delivery efficiency remarkably compared to the unmodified peptide. The splice correction levels observed with stearyl-TP10 are in fact in parity with the effects seen with the commercially available transfection agent Lipofectamine 2000. However, the inherent toxicity associated with cationic lipid-based transfections can be completely eliminated when using the stearylated TP10, making this vector highly promising for non-covalent delivery of negatively charged oligonucleotides.

Topics: Alternative Splicing; Cell Culture Techniques; Cell Proliferation; Cell Survival; Chloroquine; Culture Media; Galanin; Gene Transfer Techniques; HeLa Cells; Humans; Lipids; Phosphorothioate Oligonucleotides; Recombinant Fusion Proteins; Stearic Acids; Transfection; Wasp Venoms

RNA interference (RNAi) provides a powerful experimental tool for sequence-specific gene silencing, allowing efficient analysis of gene function in a multitude of cell types. However, application of RNAi in primary mammalian neurons has been limited by low-transfection efficiency and considerable toxicity of conventional transfection methods. In this study, we evaluated a peptide-mediated and a polymer/lipid-based cellular delivery method for siRNA into rat primary neurons and compared the results with a commonly used liposomal transfection reagent. Stearylated octaarginine (Stearyl-R8) was used as polypeptide and artificial virus-like particles (AVPs) were used as a combined liposomal-polymeric vector, since both reagents have been previously shown to successfully transfect DNA into cell lines. Stearyl-R8 and AVPs both promoted siRNA transfection into primary hippocampal neurons via the endosomal pathway. SiRNA-mediated gene silencing could be effectively induced in primary neuron cultures. In comparison with the commonly used cationic liposome transfection agent, both novel reagents were less detrimental to cell metabolic activity. We conclude that these novel transfection methods yield performances comparable to cationic liposome-mediated transfection for siRNA, while being less cytotoxic in primary neurons. Stearyl-R8 and AVPs may therefore represent novel and more cost-efficient alternatives to conventional siRNA-transfection reagents.

Topics: Animals; Arginine; Base Sequence; Cell Survival; Cells, Cultured; Hippocampus; Lipids; Neurons; Oligopeptides; Oligoribonucleotides; Pituitary Gland; Rats; RNA Interference; RNA, Small Interfering; Stearic Acids; Transfection