Benzothiazole head group based cationic lipids: synthesis and application for gene delivery

Influence of Hydrophobicity in the Hydrophilic Region of Cationic Lipids on Enhancing Nucleic Acid Delivery and Gene Editing

Intracellular delivery of biomolecules using non-viral vectors critically depends on the vectors' ability to allow the escape and release of the contents from the endosomes. Prior findings demonstrated that aromatic/hydrophobic group-containing amino acids such as phenylalanine (F) and tryptophan (W) destabilize cellular membranes by forming pores in the lipid bilayer. Taking cues from these findings, we have developed four α-tocopherol-based cationic amphiphiles by varying the aromatic/hydrophobic amino acids such as glycine (G), proline (P), phenylalanine (F), and tryptophan (W) as head groups and triazole in the linker region to study their impact on endosomal escape for the enhanced transfection efficacy. The lipids tocopherol-triazole-phenylalanine (TTF) and tocopherol-triazole-tryptophan (TTW) exhibited similar potential to commercial transfecting reagents, Lipofectamine (LF) 3000 and Lipofectamine Messenger Max (LFMM), respectively, in transfecting plasmid DNA and messenger RNA in multiple cultured cell lines. The TTW liposome was also found to be effective in delivering Cas9 mRNA and demonstrated equal efficiency of gene editing AAVS1 locus compared to LFMM in CHO, Neuro-2a, and EA.HY926 cell lines. In this current investigation, it is shown that the synthesized cationic lipids with aromatic hydrophobic R group-containing amino acids are safe, economic, and actually more efficient in nucleic acid delivery and genome-editing applications. These findings can be further explored in the genome-editing approach for treating genetic disorders.

Dicationic amphiphiles bearing an amino acid head group with a long-chain hydrophobic tail for in vitro gene delivery applications

C14-P, C14-M, and C14-S lipids formed lipoplexes using pDNA. The lipoplex cellular uptake into the cells resulted in the release of nucleic acids. C14-P lipid showed superior eGFP transfection in non-cancer cell line and more apoptosis cell death in cancer cell line.

Nicotinic acid-based cationic vectors for efficient gene delivery to glioblastoma cells

A tocopherol-conjugated nicotinic acid-based lipid (NGT) was used for liposomal formation with the co-lipid DOPE and exhibited enhanced transfection of glioblastoma cells for eGFP and β-galactosidase protein expression.

Novel α-tocopherol-ferrocene conjugates for the specific delivery of transgenes in liver cancer cells under high serum conditions

The delivery of therapeutic genes to a specific organ has drawn significant research attention. Among the pool of various delivery vectors, cationic liposomes (non-viral) are potential candidates for delivering therapeutic genes due to their low immunogenic response. Here, we have developed novel ferrocene-conjugated cationic tocopheryl aggregates as non-viral vectors. These formulations can transfer a reporter gene (pGL3; encoded for luciferase protein) specifically to liver cancer cells (HepG2 and Huh7) instead of non-hepatic cancer cells, such as Caco-2 (human colon carcinoma) and HeLa (cervical cancer) cells. The transfection efficiency (TE) of the optimum liposomal formulation is more significant than commercially available Lipofectamine 2000 (L2K). Notably, it retains its TE under high serum conditions (up to 50% FBS). A coupled effect from conjugated ferrocene and tocopherol in the cationic liposomal formulation might be responsible for the cell-specific delivery and higher serum compatibility. Therefore, the present proposed delivery system may provide a platform for further progress in terms of developing hepatotropic gene delivery systems.

Dramatic influence of the hydroxy functionality of azasugar moiety in the head group region of tocopherol-based cationic lipids on in vitro gene transfection efficacies

Cationic lipids have been effectively used as nonviral vectors for the delivery of polynucleic acids into the cytosol.

Ruthenium(ii) p-cymene complexes of pyridine-2-carboxaldehyde and 2-amino benzothiazole-based ligands: cytoselective and in vitro live cell imaging agents

A new class of DNA targeting, highly cytoselective, luminescent Ru(ii)–arene complexes was developed.

α-Tocopherol-ascorbic acid hybrid antioxidant based cationic amphiphile for gene delivery: Design, synthesis and transfection

Natural antioxidants and vitamins have potential to protect biological systems from peroxidative damage induced by peroxyl radicals, α-tocopherol (Vitamin E, lipid soluble) and ascorbic acid (vitamin C, water soluble), well known natural antioxidant molecules. In the present study we described the synthesis and biological evaluation of hybrid of these two natural antioxidants with each other via ammonium di-ethylether linker, Toc-As in gene delivery. Two control cationic lipids N14-As and Toc-NOH are designed in such a way that one is with ascorbic acid moiety and no tocopherol moiety; another is with tocopherol moiety and no ascorbic acid moiety respectively. All the three cationic lipids can form self-assembled aggregates. The antioxidant efficiencies of the three lipids were compared with free ascorbic acid. The cationic lipids (Toc-As, N14-As and Toc-NOH) were formulated individually with a well-known fusogenic co-lipid DOPE and characterization studies such as DNA binding, heparin displacement, size, charge, circular dichroism were performed. The biological characterization studies such as cell viability assay and in vitro transfection studies were carried out with the above formulations in HepG2, Neuro-2a, CHO andHEK-293T cell lines. The three formulations showed their transfection efficiencies with highest in Toc-As, moderate inN14-As and least in Toc-NOH. Interestingly, the transfection efficiency observed with the antioxidant based conjugated lipid Toc-As is found to be approximately two and half fold higher than the commercially available lipofectamine 2000 at 4:1 charge ratio in Hep G2 cell lines. In the other cell lines studied the efficiency of Toc-As is found to be either higher or similarly active compared to lipofectamine 2000. The physicochemical characterization results show that Toc-As lipid is showing maximum antioxidant potency, strong binding with pDNA, least size and optimal zeta potential. It is also found to be least toxic in all the cell lines studied especially in Neuro-2a cell lines when compared to other two lipids. In summary, the designed antioxidant lipid can be exploited as a delivering system for treating ROS related diseases such as malignancy, brain stroke, etc.

Novel 1,2,3-triazolium-based dicationic amphiphiles synthesized using click-chemistry approach for efficient plasmid delivery

Herein, we report the synthesis, characterization and evaluation of the transfection efficiencies of a series of dicationic amphiphiles designed to construct quaternary ammonium ion-based cationic lipids varying in chain length of the hydrophobic back bone connected individually through head group to a 1,2,3-triazolium cation consisting of 2-hydroxy ethyl chain as substitution. Accordingly, three dicationic amphiphiles were synthesized by "click chemistry" approach and formulated to bilayered vesicles using DOPE as a co-lipid. The transfection efficacies of these novel lipid formulations were measured and correlated with the results obtained from various physicochemical techniques. Importantly, the observed gradient in the activity profile, where the transfection potential increased with decreasing chain length of the lipid hydrophobic back bone, highlights the synergistic interplay of the lipid alkyl chain length in coordination with charge delocalization in modulating the transfection potency of these 1,2,3-triazolium-based lipids.

Cationic lipids bearing succinic-based, acyclic and macrocyclic hydrophobic domains: Synthetic studies and in vitro gene transfer

In this communication we describe the construction of four succinic-based cationic lipids, their formulation with plasmid DNA (pDNA), and an evaluation of their in vitro gene delivery into Chinese hamster ovarian (CHO-K1) cells. The cationic lipids employed in this work possess either a dimethylamine or trimethylamine headgroup, and a macrocyclic or an acyclic hydrophobic domain composed of, or derived from two 16-atom, succinic-based acyl chains. The synthesized lipids and a co-lipid of neutral charge, either cholesterol or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), were formulated in an overall 3:2 cationic-to-neutral lipid molar ratio, then complexed with plasmid DNA (pDNA). The relative transfection performance was evaluated via a comparison between matched versus mismatched formulations defined by the rigidity relationship between the lipids employed. Gel electrophoresis was used to characterize the binding of the lipid formulations with plasmid DNA and the relative degree of plasmid degradation using a DNase I degradation assay. Small angle X-ray diffraction (SAXD) was employed to characterize the packing morphology of the lipid-DNA complexes. In general, the succinic unit embedded within the hydrophobic domain of the cationic lipids was found to improve lipid hydration. The transfection assays revealed a general trend in which mismatched formulations that employed a rigid lipid combined with a non-rigid (or flexible) lipid, outperformed the matched formulations. The results from this work suggest that the design of the cationic lipid structure and the composition of the lipoplex formulation play key roles in governing the transfection performance of nonviral gene delivery agents.

Effects of heterocyclic-based head group modifications on the structure–activity relationship of tocopherol-based lipids for non-viral gene delivery

Gene therapy, a promising strategy for the delivery of therapeutic nucleic acids, is greatly dependent on the development of efficient vectors.

Hydroxyl-containing non-viral lipidic gene vectors with macrocyclic polyamine headgroups

The gene transfection abilities and structure–activity relationship of the newly designed hydroxyl-containing cationic lipids were studied in detail.

Next generation delivery system for proteins and genes of therapeutic purpose: why and how?

Proteins and genes of therapeutic interests in conjunction with different delivery systems are growing towards new heights. "Next generation delivery systems" may provide more efficient platform for delivery of proteins and genes. In the present review, snapshots about the benefits of proteins or gene therapy, general procedures for therapeutic protein or gene delivery system, and different next generation delivery system such as liposome, PEGylation, HESylation, and nanoparticle based delivery have been depicted with their detailed explanation.