Fatty acid–spermine conjugates as DNA carriers for nonviral in vivo gene delivery

Abstract

The lack of efficient in vivo gene delivery is a well-known shortcoming of nonviral delivery vectors, in particular of chemical vectors. We developed a series of novel nonviral carriers for plasmid-based in vivo gene delivery. This new transport device is based on the assembly of DNA plasmids with synthetic derivatives of naturally occurring moleculesfatty acid-spermine conjugates (or lipospermines). We tested the ability of these fatty acid conjugates to interact with plasmid DNA (pDNA) and found that they formed DNA nanocomplexes, which are protected from DNase I degradation. This protection was shown to directly correlate with the length of the aliphatic component. However, this increase in the length of the hydrocarbon chain resulted in increased toxicity. The cationic lipids used for transfection typically have a C 16 and C 18 hydrocarbon chain. Interestingly, toxicity studies, together with further characterization studies, suggested that the two most suitable candidates for in vivo delivery are those with the shortest hydrocarbon chain, butanoyl-and decanoylspermine. Morphological characterization of DNA nanocomplexes resulting from these lipospermines showed the formation of a homogenous population, with the diameter ranging approximately from 40 to 200 nm. Butanoylspermine was found to be the most promising carrier from this series, resulting in a significantly increased gene expression, in relation to naked plasmid, in both tissues herein targeted (dermis and M. tibialis anterior). Thus, we established a correlation between the in vitro properties of the ensuing DNA nanocarriers and their efficient in vivo gene expression.

Galactosylated Lipidoid Nanoparticles for Delivery of Small Interfering RNA to Inhibit Hepatitis C Viral Replication In Vivo

“…siRNA with a negative charge binds to the positively charged nitrogen of C12‐SPM to form self‐assembled nanoparticle complexes via electrostatic interactions. A previous study reported that conjugation of fatty acids to SPM improved binding and condensation of SPM to DNA, supporting the use of this fatty acid–spermine conjugate for DNA delivery . Gel retardation assays indicated that C12‐SPM could efficiently form siRNA complexes at different weight ratios of siRNA to lipidoids (1:2.5, 1:5, 1:7.5, and 1:10) (Figure b).…”

“…To prepare the lipidoids, alkyl epoxides were conjugated to polyamines. Because polyamines condense polynucleotides due to their cationic characteristics, they are expected to contribute to lipidoid complex formation with siRNA. In the epoxide ring‐opening reaction, oxide radicals of alkyl epoxides react with the amine groups of polyamines and, accordingly, alkyl epoxide tails chemically conjugate to primary and secondary amines of polyamines at 90 °C (Figure b).…”

Delivery of nucleic acids with a stearylated (RxR)4 peptide using a non-covalent co-incubation strategy

“…We first verified possible interactions between DNA and Dapa 8 peptides by an electrophoresis shift-assay that showed that all Dapa 8 peptides interacted with plasmid DNA. Similar to fatty acid-spermine conjugates (Viola et al, 2009), this interaction was concentration dependent and was more evident with increasing length of the alkyl chains. The formation of DNA particles was confirmed by DLS studies.…”

“…All DNA complexes were characterized by an average diameter between 75 and 170 nm and were stable over 24h. Surprisingly, even palmitoyl-conjugated Dapa 8 formed stable and well-defined particles (with an homogeneous distribution), whereas palmitoylconjugated spermines (Viola et al, 2009) resulted in a heterogeneous and largesized population.…”

Synthesis of fatty acid conjugates with phenols, carbohydrates, amines, and CH‐acidic compounds by Pd(0)‐catalyzed allylic substitution

“…After rotaevaporation of the solvent the crude product is purified by flash chromatography (petroleum ether/diethyl ether ¼ 4:1) to yield colorless oils with an intense odor. 24.8 (t), 28.9 (t), 29.0 (t), 29.1 (t), 33.9 (t), 34.1 (t), 51.3 (q, OCH 3 , C-1), 54.4 (q, OCH 3 , Pd 2 (dba) 3 CHCl 3 (24 mg, 0.023 mmol) and triphenylphosphine (52 mg) are dissolved under argon in absolute (abs.) tetrahydrofuran (2 mL).…”