Comparison of different commercially available cationic liposome–DNA lipoplexes: Parameters influencing toxicity and transfection efficiency

A new era of targeting cystic fibrosis with non-viral delivery of genomic medicines

Cystic fibrosis (CF) is a complex genetic respiratory disorder that necessitates innovative gene delivery strategies to address the mutations in the gene. This review delves into the promises and challenges of non-viral gene delivery for CF therapy and explores strategies to overcome these hurdles. Several emerging technologies and nucleic acid cargos for CF gene therapy are discussed. Novel formulation approaches including lipid and polymeric nanoparticles promise enhanced delivery through the CF mucus barrier, augmenting the potential of non-viral strategies. Additionally, safety considerations and regulatory perspectives play a crucial role in navigating the path toward clinical translation of gene therapy.

Physiological Barriers and Strategies of Lipid-Based Nanoparticles for Nucleic Acid Drug Delivery

Lipid-based nanoparticles (LBNPs) are currently the most promising vehicles for nucleic acid drug (NAD) delivery. Although their clinical applications have achieved success, the NAD delivery efficiency and safety are still unsatisfactory, which are, to a large extent, due to the existence of multi-level physiological barriers in vivo. It is important to elucidate the interactions between these barriers and LBNPs, which will guide more rational design of efficient NAD vehicles with low adverse effects and facilitate broader applications of nucleic acid therapeutics. This review describes the obstacles and challenges of biological barriers to NAD delivery at systemic, organ, sub-organ, cellular, and subcellular levels. The strategies to overcome these barriers are comprehensively reviewed, mainly including physically/chemically engineering LBNPs and directly modifying physiological barriers by auxiliary treatments. Then the potentials and challenges for successful translation of these preclinical studies into the clinic are discussed. In the end, a forward look at the strategies on manipulating protein corona (PC) is addressed, which may pull off the trick of overcoming those physiological barriers and significantly improve the efficacy and safety of LBNP-based NADs delivery.

Elucidating Structural Configuration of Lipid Assemblies for mRNA Delivery Systems

The development of mRNA delivery systems utilizing lipid-based assemblies holds immense potential for precise control of gene expression and targeted therapeutic interventions. Despite advancements in lipid-based gene delivery systems, a critical knowledge gap remains in understanding how the biophysical characteristics of lipid assemblies and mRNA complexes influence these systems. Herein, we investigate the biophysical properties of cationic liposomes and their role in shaping mRNA lipoplexes by comparing various fabrication methods. Notably, an innovative fabrication technique called the liposome under cryo-assembly (LUCA) cycle, involving a precisely controlled freeze-thaw-vortex process, produces distinctive onion-like concentric multilamellar structures in cationic DOTAP/DOPE liposomes, in contrast to a conventional extrusion method that yields unilamellar liposomes. The inclusion of short-chain DHPC lipids further modulates the structure of cationic liposomes, transforming them from multilamellar to unilamellar structures during the LUCA cycle. Furthermore, the biophysical and biological evaluations of mRNA lipoplexes unveil that the optimal N/P charge ratio in the lipoplex can vary depending on the structure of initial cationic liposomes. Cryo-EM structural analysis demonstrates that multilamellar cationic liposomes induce two distinct interlamellar spacings in cationic lipoplexes, emphasizing the significant impact of the liposome structures on the final structure of mRNA lipoplexes. Taken together, our results provide an intriguing insight into the relationship between lipid assembly structures and the biophysical characteristics of the resulting lipoplexes. These relationships may open the door for advancing lipid-based mRNA delivery systems through more streamlined manufacturing processes.

Reduction-Responsive Cationic Vesicles from Bolaamphiphiles with Ionizable Amino Acid or Dipeptide Polar Heads

This paper presents a study of the aggregation of cationic bolaamphiphilic molecules into vesicles. These molecules are based on a cystamine core with protonated terminal dipeptide groups. The study found that vesicles can be formed at pH 4 for all of the dipeptide-terminated bolaamphiphiles containing different combinations of l-valine, l-phenylalanine, and l-tryptophan. The concentration for aggregation onset was determined by using pyrene as a fluorescent probe or light dispersion for compounds with tryptophan. Dynamic light scattering (DLS) studies and transmission electron microscopy (TEM) reveal that the vesicles have diameters ranging from 140 to 500 nm and show the capability of loading hydrophobic cargos, such as Nile red, and their liberation in reductive environments. Furthermore, the bolaamphiphiles are only fully protonated and prone to vesicle formation at acidic pH, making them a promising alternative for gastrointestinal delivery.

The Synthesis and Transfection Activity of Disulfide Polycationic Amphiphiles

Some new polycationic amphiphiles containing a disulfide group were synthesized. Cationic liposomes formed from the compounds synthesized and a helper lipid 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine were not toxic for HEK293 and HeLa cells and were highly effective when delivering a fluorescently labeled oligodeoxyribonucleotide. The efficacy of plasmid DNA delivery depended on the cell line and the amphiphile structure, liposomes based on tetracationic amphiphiles being the most effective transfectants. These liposomes can be used for in vitro transfection of eukaryotic cells as well as for further in vivo biological studies.

Genetically engineered cellular nanoparticles for biomedical applications

In recent years, nanoparticles derived from cellular membranes have been increasingly explored for the prevention and treatment of human disease. With their flexible design and ability to interface effectively with the surrounding environment, these biomimetic nanoparticles can outperform their traditional synthetic counterparts. As their popularity has increased, researchers have developed novel ways to modify the nanoparticle surface to introduce new or enhanced capabilities. Moving beyond naturally occurring materials derived from wild-type cells, genetic manipulation has proven to be a robust and flexible method by which nanoformulations with augmented functionalities can be generated. In this review, an overview of genetic engineering approaches to express novel surface proteins is provided, followed by a discussion on the various biomedical applications of genetically modified cellular nanoparticles.

PEGylation and folic-acid functionalization of cationic lipoplexes-Improved nucleic acid transfer into cancer cells

Efficient and reliable transfer of nucleic acids for therapy applications is a major challenge. Stabilization of lipo- and polyplexes has already been successfully achieved by PEGylation. This modification reduces the interaction with serum proteins and thus prevents the lipoplexes from being cleared by the reticuloendothelial system. Problematically, this stabilization of lipoplexes simultaneously leads to reduced transfer efficiencies compared to non-PEGylated complexes. However, this reduction in transfer efficiency can be used to advantage since additional modification of PEGylated lipoplexes with functional groups enables improved selective transfer into target cells. Cancer cells overexpress folate receptors because of a significantly increased need of folate due to high cell proliferation rates. Thus, additional folate functionalization of PEGylated lipoplexes improves uptake into cancer cells. We demonstrate herein that NHS coupling chemistries can be used to modify two commercially available transfection reagents (Fuse-It-DNA and Lipofectamine® 3000) with NHS-PEG-folate for increased uptake of nucleic acids into cancer cells. Lipoplex characterization and functional analysis in cultures of cancer- and healthy cells clearly demonstrate that functionalization of PEGylated lipoplexes offers a promising method to generate efficient, stable and selective nucleic acid transfer systems.

Amphiphilic Copolymer-Lipid Chimeric Nanosystems as DNA Vectors

Lipid-polymer chimeric (hybrid) nanosystems are promising platforms for the design of effective gene delivery vectors. In this regard, we developed DNA nanocarriers comprised of a novel poly[(stearyl methacrylate-co-oligo(ethylene glycol) methyl ether methacrylate] [P(SMA-co-OEGMA)] amphiphilic random copolymer, the cationic 1,2-dioleoyl-3-(trimethylammonium) propane (DOTAP), and the zwitterionic L-α-phosphatidylcholine, hydrogenated soybean (soy) (HSPC) lipids. Chimeric HSPC:DOTAP:P[(SMA-co-OEGMA)] nanosystems, and pure lipid nanosystems as reference, were prepared in several molar ratios of the components. The colloidal dispersions obtained presented well-defined physicochemical characteristics and were further utilized for the formation of lipoplexes with a model DNA of linear topology containing 113 base pairs. Nanosized complexes were formed through the electrostatic interaction of the cationic lipid and phosphate groups of DNA, as observed by dynamic, static, and electrophoretic light scattering techniques. Ultraviolet-visible (UV-Vis) and fluorescence spectroscopy disclosed the strong binding affinity of the chimeric and also the pure lipid nanosystems to DNA. Colloidally stable chimeric/lipid complexes were formed, whose physicochemical characteristics depend on the N/P ratio and on the molar ratio of the building components. Cryogenic transmission electron microscopy (Cryo-TEM) revealed the formation of nanosystems with vesicular morphology. The results suggest the successful fabrication of these novel chimeric nanosystems with well-defined physicochemical characteristics, which can form stable lipoplexes.

Recent advances in gene therapy: genetic bullets to the root of the problem

Genetics and molecular genetic techniques have changed many perspectives and paradigms in medicine. Using genetic methods, many diseases have been cured or alleviated. Gene therapy, in its simplest definition, is application of genetic materials and related techniques to treat various human diseases. Evaluation of the trends in the field of medicine and therapeutics clarifies that gene therapy has attracted a lot of attention due to its powerful potential to treat a number of diseases. There are various genetic materials that can be used in gene therapy such as DNA, single- and double-stranded RNA, siRNA and shRNA. The main gene editing techniques used for in vitro and in vivo gene modification are ZNF, TALEN and CRISPR-Cas9. The latter has increased hopes for more precise and efficient gene targeting as it requires two separate recognition sites which makes it more specific and can also cause rapid and sufficient cleavage within the target sequence. There must be carriers for delivering genes to the target tissue. The most commonly used carriers for this purpose are viral vectors such as adenoviruses, adeno-associated viruses and lentiviruses. Non-viral vectors consist of bacterial vectors, liposomes, dendrimers and nanoparticles.

A Localized Materials-Based Strategy to Non-Virally Deliver Chondroitinase ABC mRNA Improves Hindlimb Function in a Rat Spinal Cord Injury Model

Spinal cord injury often results in devastating consequences for those afflicted, with very few therapeutic options. A central element of spinal cord injuries is astrogliosis, which forms a glial scar that inhibits neuronal regeneration post-injury. Chondroitinase ABC (ChABC) is an enzyme capable of degrading chondroitin sulfate proteoglycan (CSPG), the predominant extracellular matrix component of the glial scar. However, poor protein stability remains a challenge in its therapeutic use. Messenger RNA (mRNA) delivery is an emerging gene therapy technology for in vivo production of difficult-to-produce therapeutic proteins. Here, mineral-coated microparticles as an efficient, non-viral mRNA delivery vehicles to produce exogenous ChABC in situ within a spinal cord lesion are used. ChABC production reduces the deposition of CSPGs in an in vitro model of astrogliosis, and direct injection of these microparticles within a glial scar forces local overexpression of ChABC and improves recovery of motor function seven weeks post-injury.

Timing and duration of lipofection-mediated CRISPR/Cas9 delivery into porcine zygotes affect gene-editing events

OBJECTIVE

Lipofection-mediated introduction of the CRISPR/Cas9 system in porcine zygotes provides a simple method for gene editing, without requiring micromanipulation. However, the gene editing efficiency is inadequate. The aim of this study was to improve the lipofection-mediated gene editing efficiency by optimizing the timing and duration of lipofection.

RESULTS

Zona pellucida (ZP)-free zygotes collected at 5, 10, and 15 h from the start of in vitro fertilization (IVF) were incubated with lipofection reagent, guide RNA (gRNA) targeting GGTA1, and Cas9 for 5 h. Lipofection of zygotes collected at 10 and 15 h from the start of IVF yielded mutant blastocysts. Next, ZP-free zygotes collected at 10 h from the start of IVF were incubated with lipofection reagent, gRNA, and Cas9 for 2.5, 5, 10, or 20 h. The blastocyst formation rate of zygotes treated for 20 h was significantly lower (p < 0.05) than those of the other groups, and no mutant blastocysts were obtained. Moreover, the mutation rates of the resulting blastocysts decreased as the incubation time increased. In conclusion, a lipofection-mediated gene editing system using the CRISPR/Cas9 system in ZP-zygotes is feasible; however, further improvements in the gene editing efficiency are required.

Advancing a rapid, high throughput screening platform for optimization of lentivirus production

BACKGROUND

Lentiviral vectors (LVVs) hold great promise as delivery tools for gene therapy and chimeric antigen receptor T cell (CAR-T) therapy. Their ability to target difficult to transfect cells and deliver genetic payloads that integrate into the host genome makes them ideal delivery candidates. However, several challenges remain to be addressed before LVVs are more widely used as therapeutics including low viral vector concentrations and the absence of suitable scale-up methods for large-scale production. To address these challenges, we have developed a high throughput microscale HEK293 suspension culture platform that enables rapid screening of conditions for improving LVV productivity.

KEY RESULTS

High density culture (40 million cells mL^-1 ) of HEK293 suspension cells in commercially available media was achieved in microscale 96-deep well plate platform at liquid volumes of 200 μL. Comparable transfection and LVV production efficiencies were observed at the microscale, in conventional shake flasks and a 1-L bioreactor, indicating that significant scale-down does not affect LVV concentrations and predictivity of scale-up. Optimization of production step allowed for final yields of LVVs to reach 1.5 × 10⁷  TU mL^-1 .

CONCLUSIONS

The ability to test a large number of conditions simultaneously with minimal reagent use allows for the rapid optimization of LVV production in HEK293 suspension cells. Therefore, such a system may serve as a valuable tool in early stage process development and can be used as a screening tool to improve LVV concentrations for both batch and perfusion based systems.

In Vitro Evaluation of a Nanoparticle-Based mRNA Delivery System for Cells in the Joint

Biodegradable and bioresponsive polymer-based nanoparticles (NPs) can be used for oligonucleotide delivery, making them a promising candidate for mRNA-based therapeutics. In this study, we evaluated and optimized the efficiency of a cationic, hyperbranched poly(amidoamine)s-based nanoparticle system to deliver tdTomato mRNA to primary human bone marrow stromal cells (hBMSC), human synovial derived stem cells (hSDSC), bovine chondrocytes (bCH), and rat tendon derived stem/progenitor cells (rTDSPC). Transfection efficiencies varied among the cell types tested (bCH 28.4% ± 22.87, rTDSPC 18.13% ± 12.07, hBMSC 18.23% ± 14.80, hSDSC 26.63% ± 8.81) and while an increase of NPs with a constant amount of mRNA generally improved the transfection efficiency, an increase of the mRNA loading ratio (2:50, 4:50, or 6:50 w/w mRNA:NPs) had no impact. However, metabolic activity of bCHs and rTDSPCs was significantly reduced when using higher amounts of NPs, indicating a dose-dependent cytotoxic response. Finally, we demonstrate the feasibility of transfecting extracellular matrix-rich 3D cell culture constructs using the nanoparticle system, making it a promising transfection strategy for musculoskeletal tissues that exhibit a complex, dense extracellular matrix.

Luminescent Amphiphilic Aminoglycoside Probes to Study Transfection

We report the characterization of amphiphilic aminoglycoside conjugates containing luminophores with aggregation-induced emission properties as transfection reagents. These inherently luminescent transfection vectors are capable of binding plasmid DNA through electrostatic interactions; this binding results in an emission "on" signal due to restriction of intramolecular motion of the luminophore core. The luminescent cationic amphiphiles effectively transferred plasmid DNA into mammalian cells (HeLa, HEK 293T), as proven by expression of a red fluorescent protein marker. The morphologies of the aggregates were investigated by microscopy as well as ζ-potential and dynamic light-scattering measurements. The transfection efficiencies using luminescent cationic amphiphiles were similar to that of the gold-standard transfection reagent Lipofectamine® 2000.

Gene electrotransfer of proinflammatory chemokines CCL5 and CCL17 as a novel approach of modifying cytokine expression profile in the tumor microenvironment

The effectiveness of immunotherapy highly correlates with the degree and the type of infiltrated immune cells in the tumor tissue. Treatments based on modifying the immune cell infiltrate of the tumor microenvironment are thus gaining momentum. Therefore, the aim of our study was to investigate the effects of gene therapy with two proinflammatory chemokines CCL5 and CCL17 on inflammatory cytokine expression profile and immune cell infiltrate in two murine breast tumor models, 4T1 and E0771, and two murine colon tumor models, CT26 and MC38. In vitro, lipofection of plasmid DNA encoding CCL5 or CCL17 resulted in changes in the cytokine expression profile similar to control plasmid DNA, implying that the main driver of these changes was the entry of foreign DNA into the cell's cytosol. In vivo, gene electrotransfer resulted in high expression levels of both Ccl5 and Ccl17 transgenes in the 4T1 and CT26 tumor models. Besides a minor increase in the survival of the treated mice, the therapy also resulted in increased expression of Cxcl9 and Ifnγ, potent activators of the immune system, in CT26 tumors. However, this was not recapitulated in changes of TME, implying that a further refinement of the dosing schedule is needed.

Cationic lipids for gene delivery: many players, one goal

Lipid-based carriers represent the most widely used alternative to viral vectors for gene expression and gene silencing purposes. This class of non-viral vectors is particularly attractive for their ease of synthesis and chemical modifications to endow them with desirable properties. Despite combinatorial approaches have led to the generation of a large number of cationic lipids displaying different supramolecular structures and improved behavior, additional effort is needed towards the development of more and more effective cationic lipids for transfection purposes. With this review, we seek to highlight the great progress made in the design of each and every constituent domain of cationic lipids, that is, the chemical structure of the headgroup, linker and hydrophobic moieties, and on the specific effect on the assembly with nucleic acids. Since the complexity of such systems is known to affect their performances, the role of formulation, stability and phase behavior on the transfection efficiency of such assemblies will be thoroughly discussed. Our objective is to provide a conceptual framework for the development of ever more performing lipid gene delivery vectors.

Systematic study of liposomes composition towards efficient delivery of plasmid DNA as potential application of dermal fibroblasts targeting

The use of non-viral DNA vectors to topically treat skin diseases has demonstrated a high potential. However, vectors applied on the skin face extracellular barriers including the stratum corneum and intracellular barriers such as the endosomal escape and the nuclear targeting of the plasmid DNA. The aim of this study was to develop a formulation suitable for dermal application and effective for delivering plasmid DNA into cells. Different formulations were prepared using different cationic lipids (DOTAP, DC-Chol, DOTMA) and co-lipids (DOPE, DSPE). Lipoplexes were produced by complexing liposomes with plasmid DNA at different pDNA/CL (w/w) ratios. Our results showed that appropriate pDNA/CL ratios allowing total complexation of plasmid DNA differed depending on the structure of the lipid used. The transfection rates showed that (i) higher rates were obtained with DOTMA lipoplexes, (ii) DC-Chol lipoplexes provided a transfection twice as important as DOTAP lipoplexes and (iii) when DSPE was added, the cytotoxicity decreased while transfection rates were similar. We found that formulations composed of DC-Chol:DOPE:DSPE or DOTMA:DOPE were appropriate to complex plasmid DNA and to transfect human primary dermal fibroblasts with efficacy and limited cytotoxicity. Therefore, these formulations are highly promising in the context of gene therapy to treat skin diseases.

An artificial cationic oligosaccharide combined with phosphorothioate linkages strongly improves siRNA stability

Small interfering RNAs (siRNAs) are potential tools for gene-silencing therapy, but their instability is one of the obstacles in the development of siRNA-based drugs. To improve siRNA stability, we synthesised a double-stranded RNA-binding cationic oligodiaminogalactose 4mer (ODAGal4) and investigated here its characteristics for siRNA stabilisation in vitro. ODAGal4 improved the resistance of various siRNAs against serum degradation. The effect of ODAGal4 on siRNA stabilisation was further amplified by introduction of modified nucleotides into the siRNA. In particular, a combination of ODAGal4 and incorporation of phosphorothioate linkages into the siRNA prominently prevented degradation by serum. The half-lives of fully phosphorothioate-modified RNA duplexes with ODAGal4 were more than 15 times longer than those of unmodified siRNAs without ODAGal4; this improvement in serum stability was superior to that observed for other chemical modifications. Serum degradation assays of RNAs with multiple chemical modifications showed that ODAGal4 preferentially improves the stability of RNAs with phosphorothioate modification among chemical modifications. Furthermore, melting temperature analysis showed that ODAGal4 greatly increases the thermal stability of phosphorothioate RNAs. Importantly, ODAGal4 did not interrupt gene-silencing activity of all the RNAs tested. Collectively, these findings demonstrate that ODAGal4 is a potent stabiliser of siRNAs, particularly nucleotides with phosphorothioate linkages, representing a promising tool in the development of gene-silencing therapies.

Enhanced macrophage delivery to the colon using magnetic lipoplexes with a magnetic field

Magnetically guided cell delivery systems would be valuable to achieve effective macrophage-based cell therapy for colonic inflammatory diseases. In the current study, we developed a method for the efficient and simultaneous introduction of superparamagnetic iron oxide nanoparticles (SPIONs) and plasmid DNA (pDNA) into RAW264 murine macrophage-like cells using SPION-incorporated cationic liposome/pDNA complexes (magnetic lipoplexes). SPIONs and pDNA were introduced for magnetization and functionalization of the macrophages, respectively. We also evaluated the adhesive properties of magnetized RAW264 cells using magnetic lipoplexes in the murine colon under a magnetic field. Significant cellular association and gene expression without cytotoxicity were observed when magnetic cationic liposomes and pDNA were mixed at a weight ratio of 10:1, and SPION concentration and magnetic field exposure time was 0.1 mg/mL and 10 min, respectively. We also observed that cytokine production in magnetized RAW264 cells was similar to that in non-treated RAW264 cells, whereas nitric oxide production was significantly increased in magnetized RAW264 cells. Furthermore, magnetized RAW264 cells highly adhered to a Caco-2 cell monolayer and colon in mice, under a magnetic field. These results suggest that this magnetic cell delivery system can improve the colonic delivery of macrophages and its therapeutic efficacy against colonic inflammatory diseases.

Lipofection with estrone-based luminophores featuring aggregation-induced emission properties

In this communication we present the use of a novel class of luminophores with aggregation-induced emission (AIE) properties based on the steroid estrone. These molecules were equipped with cationic residues yielding amphiphiles suitable for lipofection. To this end, self-assembled luminescent structures were formed in aqueous media and mixed with a red-fluorescent protein expressing plasmid, yielding lipoplexes with increased emission intensity. These luminescent lipoplexes were able to efficiently transfect HeLa and HEK 293T cells and were able to be tracked due to the aggregation induced-emission properties.

A novel class of cationic amphiphiles based on estrone with aggregation-induced emission (AIE) properties is described which is able to transfect different cell lines. The AIE-effect is used to track the transfection process.

Evaluation of novel cationic gene based liposomes with cyclodextrin prepared by thin film hydration and microfluidic systems

In gene delivery, non-viral vectors have become the preferred carrier system for DNA delivery. They can overcome major viral issues such as immunogenicity and mutagenicity. Cationic lipid-mediated gene transfer is one of the most commonly used non-viral vectors, which have been shown to be a safe and effective carrier. However, their use in gene delivery often exhibits low transfection efficiency and stability. The aim of this study was to examine the effectiveness of novel non-viral gene delivery systems. This study has investigated the encapsulation and transfection efficiency of cationic liposomes prepared from DOTAP and carboxymethyl-β-cyclodextrin (CD). The encapsulation efficiency of the CD-lipoplex complexes were also studied with and without the addition of Pluronic-F127, using both microfluidic and thin film hydration methods. In vitro transfection efficiencies of these complexes were determined in COS7 and SH-SY5Y cell lines. Formulation stability was evaluated using liposomes size, zeta potential and polydispersity index. In addition, the external morphology was studied using transmission electron microcopy (TEM). Results revealed that formulations produced by microfluidic method had smaller, more uniform and homogenious size and zeta-potential as well as higher encapsulation efficiency when compared with liposomes manufactured by thin film hydration method. Overall, the results of this study show that carboxymethyl-β-cyclodextrin increased lipoplexes' encapsulation efficiency using both NanoAssemblr and rotary evaporator manufacturing processes. However, this increase was reduced slightly following the addition of Pluronic-F127. The addition of carboxymethyl-β-cyclodextrin to cationic liposomes resulted in an increase in transfection efficiency in mammalian cell lines. However, this increase appeared to be cell line specific, COS7 showed higher transfection efficiency compared to SH-SY5Y.

Transfection Efficiency Evaluation and Endocytosis Exploration of Different Polymer Condensed Agents

DNA condensed agents can improve the transfection efficiency of the cationic liposome delivery system. However, various condensed agents have distinct transfection efficiency and cellular cytotoxicity. The object of this study was to screen the optimal agents with the high transfection efficiency and low cytotoxicity from four polymer compressive materials, polyethylenimine (PEI), chitosan, poly-l-lysine (PLL), and spermidine. DNA was precompressed with these four agents and then combined to cationic liposomes. Subsequently, the entrapment and transfection efficiency of the obtained complexes were investigated. Finally, the particle sizes, cytotoxicity, and endocytosis fashion of these copolymers (Lipo-PEI, Lipo-chitosan, Lipo-PLL, and Lipo-spermidine) were examined. It was found that these four copolymers had significantly lower cytotoxicity and higher transfection efficiency (45.5%, 42.4%, 36.8%, and 47.4%, respectively) than those in the control groups. The transfection efficiency of Lipo-PEI and Lipo-spermidine copolymers were better than the other two copolymers. In 293T cells, nystatin significantly inhibited the transfection efficiency of Lipo-PEI-DNA and Lipo-spermidine-DNA (51.88% and 46.05%, respectively), which suggest that the endocytosis pathway of Lipo-spermidine and Lipo-PEI copolymers was probably caveolin dependent. Our study indicated that these dual-degradable copolymers especially liposome-spermidine copolymer could be used as the potential biocompatible gene delivery carriers.

Development of a Novel Polymer-Based mRNA Coating for Surgical Suture to Enhance Wound Healing

A therapeutic strategy to improve wound healing has become an increasingly important medical task due to the rising incidence of adiposity and type II diabetes as well as the proceeding population aging. In order to cope with the resulting burdens, new strategies to achieve rapid and complete wound healing must now be developed. Accordingly, the development of a bioactive wound dressing in the form of a messengerRNA (mRNA)-bearing poly(lactide-co-glycolide acid) (PLGA) coating on surgical suture is being pushed further with this study. Furthermore, the evaluation of the polymer-based transfection reagent Viromer RED has shown that it can be used for the transfection of eukaryotic cells: The mRNA gets properly complexed and translated into a functional protein. In addition, the mRNA-PLGA coating triggered the expression of the keratinocyte growth factor (KGF) in HaCat cells although KGF is not expressed under physiological conditions. Moreover, transfection via surgical sutures coated with mRNA does not affect the cell viability and a proinflammatory reaction in the transfected cells is not induced. These properties make the mRNA-PLGA coating very attractive for the in vivo application. For the future, this could mean that through the use of mRNA-coated sutures in surgical wound closure, cells in the wound area can be transfected directly, thus accelerating and improving wound healing.

Lipid-Based DNA Therapeutics: Hallmarks of Non-Viral Gene Delivery

Gene therapy is a promising strategy for the treatment of monogenic disorders. Non-viral gene delivery systems including lipid-based DNA therapeutics offer the opportunity to deliver an encoding gene sequence specifically to the target tissue and thus enable the expression of therapeutic proteins in diseased cells. Currently, available gene delivery approaches based on DNA are inefficient and require improvements to achieve clinical utility. In this Review, we discuss state-of-the-art lipid-based DNA delivery systems that have been investigated in a preclinical setting. We emphasize factors influencing the delivery and subsequent gene expression in vitro, ex vivo, and in vivo. In addition, we cover aspects of nanoparticle engineering and optimization for DNA therapeutics. Finally, we highlight achievements of lipid-based DNA therapies in clinical trials.

Interaction of DNA with likely-charged lipid monolayers: An experimental study

Anionic lipids are increasingly being used in lipoplexes for synthetic gene vectors as an alternative to cationic lipids. This is primarily due to their lower toxicity, which makes them biocompatible and adaptable to be tissue specific. However, anionic lipoplexes require the presence of multivalent cations to promote the electrostatic attraction between DNA and anionic lipid mono- and bilayers. In this work we provide for the first time experimental results of the adsorption of linear DNA onto anionic/zwitterionic lipid monolayers without any addition of cations. This is demonstrated experimentally by means of Langmuir monolayers of DOPE/DOPG (1:1) lipids spread on a water subphase that contains calf thymus DNA. The adsorption of DNA onto anionic/zwitterionic lipid monolayers is discussed in terms of the surface pressure-molecular area isotherms recorded in the absence and in the presence of different electrolytes. Measurements of the surface potential provide additional evidence of the different interaction of DNA anionic/zwitterionic lipid monolayers depending on the presence and nature of electrolyte. These experimental results are further analysed in terms of the overall dipole moment normal to the monolayers providing new insight into the behaviour of anionic lipoplexes and the role of zwitterionic lipids.

Errors in measuring plasma free fatty acid concentrations with a popular enzymatic colorimetric kit

OBJECTIVES

Our goal was to test whether an enzymatic, colorimetric assay, the WAKO NEFA kit, provides information equivalent to liquid chromatography (LC) LC-based measures of free fatty acid (FFA).

DESIGN & METHODS

We reanalyzed nadir FFA samples from 109 volunteers from a previous study where we demonstrated that maximal suppression of FFA concentrations predicts metabolic abnormalities in humans; the results from the WAKO NEFA kit, which has been widely used for over three decades, could not replicate our findings. We conducted additional studies to directly compare results from this kit to our LC-mass spectrometry (LC/MS) method that was validated by our LC-UV detection method.

RESULTS

Plasma samples with FFA concentrations ranging from 0.015 to 1.813 mmol/L were measured both by LC-mass spectrometry (LC/MS) and by the WAKO NEFA kit. Despite good overall agreement (R² = 0.86), the slope was significantly different from 1.0 and the intercept was significantly different from zero. The results from the kit were especially discrepant with FFA concentrations <0.200 and >1.000 mmol/L. Some of the discrepancy was related to the use of oleate as the standard solution for the kit and the substrate specificity of the kit enzymes for different fatty acids. Despite attempts to improve the kit by modifying the reaction time, sample volume and the types of standard solutions, we could not obtain a satisfactory agreement between the WAKO NEFA results and LC/MS.

CONCLUSIONS

The WAKO NEFA kit should not be used when high precision and accuracy of FFA concentrations over a wide range is required.

Development and biochemical and immunological characterization of early passage and immortalized bovine intestinal epithelial cell lines from the ileum of a young calf

The intestinal epithelium is a major site of interaction with pathogens. In bovine intestinal epithelial cells (BIECs), Toll-like receptors (TLRs) play an important role in innate immune responses against enteric pathogens. This study is aimed at establishing a stable bovine intestinal epithelial cell line that can be maintained by a continuous passage so that studies on innate immune responses against various enteric pathogens can be performed. The main goal was to establish pure cultures of primary and immortalized bovine intestinal epithelial cells from the ileum and then characterize them biochemically and immunologically. Mixed epithelial and fibroblast bovine ileal intestinal cultures were first established from a 2-day old calf. Limiting dilution method was used to obtain a clone of epithelial cells which was characterized using immunocytochemistry (ICC). The selected clone BIEC-c4 was cytokeratin positive and expressed low levels of vimentin, confirming the epithelial cell phenotype. Early passage BIEC-c4 cells were transfected with either simian virus 40 (SV40) large T antigen or human telomerase reverse transcriptase (hTERT), or human papillomavirus (HPV) type 16E6/E7 genes to establish three immortalized BIEC cell lines. The expression of SV40, hTERT and HPV E6/E7 genes in immortalized BIECs was confirmed by a polymerase chain reaction (PCR). Immunocytochemistry and immunofluorescence assays also confirmed the expression of SV40, hTERT and HPV E6 proteins. The immortalized BIECs were cytokeratin positive and all except HPV-BIECs expressed low levels of vimentin. A growth kinetics study indicated that there were no significant differences in the doubling time of immortalized BIECs as compared to early passage BIEC-c4 cells. All four BIEC types expressed TLR 1-10 genes, with TLR 3 and 4 showing higher expression across all cell types. These newly established early passage and immortalized BIEC cell lines should serve as a good model for studying infectivity, pathogenesis and innate immune responses against enteric pathogens.

Highly efficient siRNA transfection in macrophages using apoptotic body-mimic Ca-PS lipopolyplex

Background

The discovery and development of RNA interference has made a tremendous contribution to the biochemical and biomedical field. However, liposomal transfection protocols to deliver siRNAs to certain types of cells, eg, immune cells, are not viable due to exceedingly low transfection efficiency. While viral delivery and electroporation are two widely adopted approaches to transfect immune cells, they are associated with certain drawbacks such as complexity of preparation, biosafety issues, and high cytotoxicity. We believe amendments can be made to liposomal formulas and protocols to achieve a highly efficient knockdown of genes by liposome-loaded siRNAs.

Aim

The aim of this study was to use the apoptotic-mimic Ca-PS lipopolyplex to achieve highly efficient siRNA knockdown of genes in the hard-to-transfect macrophages with reduced cytotoxicity and more efficient cellular uptake.

Results

We devised an anionic liposomal formula containing phosphatidylserine to mimic the apoptotic body, the Ca-PS lipopolyplex. Ca-PS lipopolyplex was proven to be capable of delivering and effecting efficient gene knockdown in multiple cell lines at lowered cytotoxicity. Among the two types of macrophages, namely Ana-1 and bone-marrow derived macrophages, Ca-PS lipopolyplex showed an improvement in knockdown efficiency, as high as 157%, over Lipo2000. Further investigations revealed that Ca-PS promotes increased cellular uptake, lysosomal escape and localization of siRNAs to the perinuclear regions in macrophages. Lastly, transfection by Ca-PS lipopolyplex did not induce spontaneous polarization of macrophages.

Conclusion

The apoptotic body-mimic Ca-PS lipopolyplex is a stable, non-cytotoxic liposomal delivery system for siRNAs featuring vastly improved potency for macrophages and lowered cytotoxicity. It is speculated that Ca-PS lipopolyplex can be applied to other immune cells such as T cells and DC cells, but further research efforts are required to explore its promising potentials.

Preparation of gene drug delivery systems of cationic peptide lipid with 0G-PAMAM as hydrophilic end and its biological properties evaluation

As an efficient gene delivery, non-viral vectors should have high transfection efficiency, excellent endosomal escape, low cytotoxicity, and the ability to rapidly release the gene into the cytoplasm.Cationic liposome have been widely used as efficient gene carriers, but the cytotoxicity, rapid degradation and low cellular uptake are major drawback impeding its further appolication. Herein, with double lauric acid as hydrophobic chains, tartaric acid as skeleton, 0 generation PAMAM modified with lysine as hydrophilic head, a new type cationic peptide lipid was synthetised. The alkyl chain promote lipid across cell membranes and with membrane fusion, 0 generation PAMAM modified with lysine hydrophilic end amino can contain a large number of protons which can change into ammonium and combine with the DNA negatively charge phosphate groups. It is expected that this carrier has low toxicity, high transfection efficiency and targeting property. By adjusting the cationic liposome/gene weight ratio, the transfection system was optimized to improved gene transfection efficiency, reduce cytotoxicity, and increase property and stability, etc.

Cationic Liposomes Carrying siRNA: Impact of Lipid Composition on Physicochemical Properties, Cytotoxicity and Endosomal Escape

In recent year, cationic liposomes have gained a lot of attention for siRNA delivery. Despite this, intracellular barriers as endosomal escape and cytosolic delivery of siRNA still represent a challeng, as well as the cytotoxicity due to cationic lipids. To address these issues, we developed four liposomal formulations, composed of two different cationic lipids (DOTAP and DC-Cholesterol) and different ratio of co-lipids (cholesterol and DOPE). The objective is to dissect these impacts on siRNA efficacy and cytotoxicity. Liposomes were complexed to siRNA at six different N/P molar ratios, physico-chemical properties were characterized, and consequently, N/P 2.5, 5 and 10 were selected for in vitro experiments. We have shown that cytotoxicity is influenced by the N/P ratio, the concentration of cationic lipid, as well as the nature of the cationic lipid. For instance, cell viability decreased by 70% with liposomes composed of DOTAP/Cholesterol/DOPE 1/0.75/0.5 at a N/P ratio 10, whereas the same formulation at a N/P ratio of 2.5 was safe. Interestingly, we have observed differences in terms of mRNA knock-down efficiency, whereas the transfection rate was quite similar for each formulation. Liposomes containing 50% of DOPE induced a mRNA silencing of around 80%. This study allowed us to highlight crucial parameters in order to develop lipoplexes which are safe, and which induce an efficient intracytoplasmic release of siRNA.

Biophysical and biological contributions of polyamine-coated carbon nanotubes and bidimensional buckypapers in the delivery of miRNAs to human cells

Recent findings in nanomedicine have revealed that carbon nanotubes (CNTs) can be used as potential drug carriers, therapeutic agents and diagnostics tools. Moreover, due to their ability to cross cellular membranes, their nanosize dimension, high surface area and relatively good biocompatibility, CNTs have also been employed as a novel gene delivery vector system. In our previous work, we functionalized CNTs with two polyamine polymers, polyethyleneimine (PEI) and polyamidoamine dendrimer (PAMAM). These compounds have low cytotoxicity, ability to conjugate microRNAs (such as miR-503) and, at the same time, transfect efficiently endothelial cells. The parameters contributing to the good efficiency of transfection that we observed were not investigated in detail. In fact, the diameter and length of CNTs are important parameters to be taken into account when evaluating the effects on drug delivery efficiency. In order to investigate the biophysical and biological contributions of polymer-coated CNTs in delivery of miRNAs to human cells, we decided to investigate three different preparations, characterized by different dimensions and aspect ratios. In particular, we took into account very small CNTs, a suspension of CNTs starting from the commercial product and a 2D material based on CNTs (ie, buckypapers [BPs]) to examine the transfection efficiency of a rigid scaffold. In conclusion, we extensively investigated the biophysical and biological contributions of polyamine-coated CNTs and bidimensional BPs in the delivery of miRNAs to human cells, in order to optimize the transfection efficiency of these compounds to be employed as efficient drug delivery vectors in biomedical applications.

Biophysical and biological contributions of polyamine-coated carbon nanotubes and bidimensional buckypapers in the delivery of miRNAs to human cells

Recent findings in nanomedicine have revealed that carbon nanotubes (CNTs) can be used as potential drug carriers, therapeutic agents and diagnostics tools. Moreover, due to their ability to cross cellular membranes, their nanosize dimension, high surface area and relatively good biocompatibility, CNTs have also been employed as a novel gene delivery vector system. In our previous work, we functionalized CNTs with two polyamine polymers, polyethyleneimine (PEI) and polyamidoamine dendrimer (PAMAM). These compounds have low cytotoxicity, ability to conjugate microRNAs (such as miR-503) and, at the same time, transfect efficiently endothelial cells. The parameters contributing to the good efficiency of transfection that we observed were not investigated in detail. In fact, the diameter and length of CNTs are important parameters to be taken into account when evaluating the effects on drug delivery efficiency. In order to investigate the biophysical and biological contributions of polymer-coated CNTs in delivery of miRNAs to human cells, we decided to investigate three different preparations, characterized by different dimensions and aspect ratios. In particular, we took into account very small CNTs, a suspension of CNTs starting from the commercial product and a 2D material based on CNTs (ie, buckypapers [BPs]) to examine the transfection efficiency of a rigid scaffold. In conclusion, we extensively investigated the biophysical and biological contributions of polyamine-coated CNTs and bidimensional BPs in the delivery of miRNAs to human cells, in order to optimize the transfection efficiency of these compounds to be employed as efficient drug delivery vectors in biomedical applications.

Functionalization of microparticles with mineral coatings enhances non-viral transfection of primary human cells

Gene delivery to primary human cells is a technology of critical interest to both life science research and therapeutic applications. However, poor efficiencies in gene transfer and undesirable safety profiles remain key limitations in advancing this technology. Here, we describe a materials-based approach whereby application of a bioresorbable mineral coating improves microparticle-based transfection of plasmid DNA lipoplexes in several primary human cell types. In the presence of these mineral-coated microparticles (MCMs), we observed up to 4-fold increases in transfection efficiency with simultaneous reductions in cytotoxicity. We identified mechanisms by which MCMs improve transfection, as well as coating compositions that improve transfection in three-dimensional cell constructs. The approach afforded efficient transfection in primary human fibroblasts as well as mesenchymal and embryonic stem cells for both two- and three-dimensional transfection strategies. This MCM-based transfection is an advancement in gene delivery technology, as it represents a non-viral approach that enables highly efficient, localized transfection and allows for transfection of three-dimensional cell constructs.

A novel rapid and reproducible flow cytometric method for optimization of transfection efficiency in cells

Transfection is one of the most frequently used techniques in molecular biology that is also applicable for gene therapy studies in humans. One of the biggest challenges to investigate the protein function and interaction in gene therapy studies is to have reliable monospecific detection reagents, particularly antibodies, for all human gene products. Thus, a reliable method that can optimize transfection efficiency based on not only expression of the target protein of interest but also the uptake of the nucleic acid plasmid, can be an important tool in molecular biology. Here, we present a simple, rapid and robust flow cytometric method that can be used as a tool to optimize transfection efficiency at the single cell level while overcoming limitations of prior established methods that quantify transfection efficiency. By using optimized ratios of transfection reagent and a nucleic acid (DNA or RNA) vector directly labeled with a fluorochrome, this method can be used as a tool to simultaneously quantify cellular toxicity of different transfection reagents, the amount of nucleic acid plasmid that cells have taken up during transfection as well as the amount of the encoded expressed protein. Finally, we demonstrate that this method is reproducible, can be standardized and can reliably and rapidly quantify transfection efficiency, reducing assay costs and increasing throughput while increasing data robustness.

Aqueous dispersions of nanostructures formed through the self-assembly of iminolipids with exchangeable hydrophobic termini

The addition of amines to an aldehyde surfactant, which was designed to be analogous to didodecyldimethylammonium bromide, gave exchangeable "iminolipids" that self-assembled to give stable aqueous dispersions of nano-sized vesicles. For example, sonication of suspensions of the n-hexylamine-derived iminolipid gave vesicles 50 to 200 nm in diameter that could encapsulate a water-soluble dye. The iminolipids could undergo dynamic exchange with added amines, and the resulting equilibrium constants (K_rel) were quantified by ¹H NMR spectroscopy. In the absence of lipid self-assembly, in CDCl₃, the assayed primary amines gave very similar K_rel values. However in D₂O the value of K_rel generally increased with increasing amine hydrophobicity, consistent with partitioning into a self-assembled bilayer. Amines with aromatic groups showed significantly higher values of K_rel in D₂O compared to similarly hydrophobic alkylamines, suggesting that π-π interactions favor lipid self-assembly. Given this synergistic relationship, π-rich pyrenyliminolipids were created and used to exfoliate graphite, leading to aqueous dispersions of graphene flakes that were stable over several months.

Preliminary study of a novel transfection modality for in vivo siRNA delivery to vocal fold fibroblasts

OBJECTIVE

An obstacle to clinical use of RNA-based gene suppression is instability and inefficiency of current delivery modalities. Nanoparticle delivery likely holds great promise, but the kinetics and transfection conditions must be optimized prior to in vivo utility. We investigated a RNA nanoparticle complex incorporating a lipitoid transfection reagent in comparison to a commercially available reagent.

STUDY DESIGN

In vitro.

METHODS

We investigated which variables influence transfection efficiency of lipitoid oligomers and a commercially available reagent across species, in vitro. These variables included duration, dose, and number of administrations, as well as serum and media conditions. The target gene was Smad3, a signaling protein in the transforming growth factor-β cascade implicated in fibroplasia in the vocal folds and other tissues.

RESULTS

The two reagents suppressed Smad3 mRNA for up to 96 hours; lipitoid performed favorably and comparably. Both compounds yielded 60% to 80% mRNA knockdown in rat, rabbit, and human vocal fold fibroblasts (P < 0.05 relative to control). Dose and number of administrations played a significant role in gene suppression (P < 0.05). Suppression was more dose-sensitive with lipitoid. At a constant siRNA concentration, a 50% decrease in gene expression was observed in response to a five-fold increase in lipitoid concentration. Increased number of administrations enhanced gene suppression, ∼45% decrease between one and four administrations. Neither serum nor media type altered efficiency.

CONCLUSION

Lipitoid effectively knocked down Smad3 expression across multiple transfection conditions. These preliminary data are encouraging, and lipitoid warrants further investigation with the goal of clinical utility.

LEVEL OF EVIDENCE

NA. Laryngoscope, 127:E231-E237, 2017.

Promoting Vaginal Distribution of E7 and MCL-1 siRNA-Silencing Nanoparticles for Cervical Cancer Treatment

There is an urgent need to develop a less aggressive and more effective treatment against cervical lesions induced by different high-risk human papillomavirus (HR-HPV). We investigated the potential of a cocktail of small interfering RNA (siRNA) directed against the oncoprotein E6 (E6), the oncoprotein E7 (E7), or the antiapoptotic protein MCL-1 (MCL-1). The combination of siRNA anti-E7 and anti-MCL-1 demonstrated high efficacy on multiple HPV16 and HPV18 cell lines and no effects on healthy keratinocytes. This gene therapy has been considered for a vaginal administration since this route of application holds high potential for the treatment of diseases in the female reproductive tracts. Therefore, PEGylated lipoplexes have been designed and characterized to protect siRNA and to diffuse in the mucosal environment before they reach the cervico/vaginal epithelium. This new nanovector complexed to the combination of active siRNA induced an efficient mRNA knockdown since biological effects were obtained in vitro. This work also provided evidence that the PEGylated lipoplexes had appropriate physicochemical properties to diffuse into a mucin network according to size measurement experiments in artificial mucus. After demonstrating the distribution and the efficacy of siRNA into a 3D-cervical model lesion and through porcine vaginal mucosa, in vivo experiments in mouse have been performed under physiological conditions. This study revealed a complete and sustained coverage of the mucosal epithelium following an unique vaginal administration of fluorescent PEGylated lipoplexes. Overall, our results showed the potential of the PEGylated lipoplexes for the prolonged delivery of active siRNA to treat HPV-induced lesions.

A biophysical study of gene nanocarriers formed by anionic/zwitterionic mixed lipids and pillar[5]arene polycationic macrocycles

A multivalent cationic macrocycle is used as a mediator between plasmid DNAs and anionic lipids (ALs) to build an efficient and safe gene nanocarrier.

Nanoparticles for radiooncology: Mission, vision, challenges

Cancer is one of the leading non-communicable diseases with highest mortality rates worldwide. About half of all cancer patients receive radiation treatment in the course of their disease. However, treatment outcome and curative potential of radiotherapy is often impeded by genetically and/or environmentally driven mechanisms of tumor radioresistance and normal tissue radiotoxicity. While nanomedicine-based tools for imaging, dosimetry and treatment are potential keys to the improvement of therapeutic efficacy and reducing side effects, radiotherapy is an established technique to eradicate the tumor cells. In order to progress the introduction of nanoparticles in radiooncology, due to the highly interdisciplinary nature, expertise in chemistry, radiobiology and translational research is needed. In this report recent insights and promising policies to design nanotechnology-based therapeutics for tumor radiosensitization will be discussed. An attempt is made to cover the entire field from preclinical development to clinical studies. Hence, this report illustrates (1) the radio- and tumor-biological rationales for combining nanostructures with radiotherapy, (2) tumor-site targeting strategies and mechanisms of cellular uptake, (3) biological response hypotheses for new nanomaterials of interest, and (4) challenges to translate the research findings into clinical trials.

Temperature and pH sensitivity of a stabilized self-nanoemulsion formed using an ionizable lipid-like material via an oil-to-surfactant transition

Lipids functionalized with tertiary amines (ionizable lipids) for a pH-dependent positive charge have been developed extensively as a carrier material for delivering nucleic acids. We previously developed an SS-cleavable proton-activated lipid-like material (ssPalm) as a component of a functionalized lipid envelope structure of a nanoparticle that encapsulated plasmid DNA and short interfering RNA. In this study, we report on the unique characteristics of such an ionizable lipid: the formation of a nano-sized emulsion (ave. 40nm) via pH-triggered self-emulsification in the absence of a cargo (nucleic acids). The particle has a neutral charge at physiological pH and is stabilized by helper lipids and polyethyleneglycol (PEG)-conjugated lipids. The generalized polarization of 6-dodecanoyl-2-dimethylaminonaphthalene (Laurdan), which indicates the surface polarity caused by the invasion of water onto the surface, changes dynamically in response to pH and temperature, while the fluidity of the intra-particle compartment, as measured by the fluorescence anisotropy of 1,6-Diphenyl-1,3,5-hexatriene (DPH), is not affected. Even when the particle contains a high density of PEG on the surface, it shows a high fusogenecity to negatively charged liposomes in response to an acidic pH to a higher degree than a conventional cationic lipid. These characteristics suggest that the ssPalm particle possesses unique properties for delivering lipophilic drugs across the biomembrane.

Delivery methods to increase cellular uptake and immunogenicity of DNA vaccines

DNA vaccines are ideal candidates for global vaccination purposes because they are inexpensive and easy to manufacture on a large scale such that even people living in low-income countries can benefit from vaccination. However, the potential of DNA vaccines has not been realized owing mainly to the poor cellular uptake of DNA in vivo resulting in the poor immunogenicity of DNA vaccines. In this review, we discuss the benefits and shortcomings of several promising and innovative non-biological methods of DNA delivery that can be used to increase cellular delivery and efficacy of DNA vaccines.