Lipid-based emulsion system as non-viral gene carriers

Nanoemulsions as Gene Delivery in Mucopolysaccharidosis Type I-A Mini-Review

Mucopolysaccharidosis type I (MPS I) is a rare monogenic disease in which glycosaminoglycans' abnormal metabolism leads to the storage of heparan sulfate and dermatan sulfate in various tissues. It causes its damage and impairment. Patients with the severe form of MPS I usually do not live up to the age of ten. Currently, the therapy is based on multidisciplinary care and enzyme replacement therapy or hematopoietic stem cell transplantation. Applying gene therapy might benefit the MPS I patients because it overcomes the typical limitations of standard treatments. Nanoparticles, including nanoemulsions, are used more and more in medicine to deliver a particular drug to the target cells. It allows for creating a specific, efficient therapy method in MPS I and other lysosomal storage disorders. This article briefly presents the basics of nanoemulsions and discusses the current state of knowledge about their usage in mucopolysaccharidosis type I.

Delivery of transcription factors as modulators of cell differentiation

Fundamental studies performed during the last decades have shown that cell fate is much more plastic than previously considered, and technologies for its manipulation are a keystone for many new tissue regeneration therapies. Transcription factors (TFs) are DNA-binding proteins that control gene expression, and they have critical roles in the control of cell fate and other cellular behavior. TF-based therapies have much medical potential, but their use as drugs depends on the development of suitable delivery technologies that can help them reach their action site inside of the cells. TFs can be used either as proteins or encoded in polynucleotides. When used in protein form, many TFs require to be associated to a cell-penetrating peptide or another transduction domain. As polynucleotides, they can be delivered either by viral carriers or by non-viral systems such as polyplexes and lipoplexes. TF-based therapies have extensively shown their potential to solve many tissue-engineering problems, including bone, cartilage and cardiac regeneration. Yet, their use has expanded beyond regenerative medicine to other prominent disease areas such as cancer therapy and immunomodulation. This review summarizes some of the delivery options for effective TF-based therapies and their current main applications.

Cyclodextrins based delivery systems for macro biomolecules

Macro biomolecules are of vital importance in regulating the biofunctions in organisms, in which proteins (including peptides when mentioned below) and nucleic acids (NAs) are the most important. Therefore, these proteins and NAs can be applied as "drugs" to regulate the biofunctions from abnormal to normal. Either for proteins and NAs, the most challenging thing is to avoid the biodegradation or physicochemical degradation before they reach the targeted location, and then functions as complete functional structures. Hence, appropriate delivery systems are very important which can protect them from these degradations. Cyclodextrins (CDs) based delivery systems achieved mega successes due to their outstanding pharmaceutical properties and there have been several reviews on CDs based small molecule drug delivery systems recently. But for biomolecules, which are getting more and more important for modern therapies, however, there are very few reviews to systematically summarize and analyze the CDs-based macro biomolecules delivery systems, especially for proteins. In this review, there were some of the notable examples were summarized for the macro biomolecules (proteins and NAs) delivery based on CDs. For proteins, this review included insulin, lysozyme, bovine serum albumin (BSA), green fluorescent protein (GFP) and IgG's, etc. deliveries in slow release, stimulating responsive release or targeting release manners. For NAs, this review summarized cationic CD-polymers and CD-cluster monomers as NAs carriers, notably, including the multicomponents targeting CD-based carriers and the virus-like RNA assembly method siRNA carriers.

[12]aneN3-Based Gemini-Type Amphiphiles with Two-Photon Absorption Properties for Enhanced Nonviral Gene Delivery and Bioimaging

Although a plethora of nonviral gene vectors have been developed for potential gene therapy, imageable gemini surfactants with stimuli-responsiveness and high transfection efficiency are still scarce for gene delivery. Herein, three gemini amphiphiles (DEDPP-4/8/12) consisting of an aggregation-induced emission (AIE) central fluorophore: 5,6-diphenylpyrazine-2,3-diester (DEDPP), decorated with triazole-[12]aneN₃ as the hydrophilic moiety and alkyl chains of various lengths as the hydrophobic moiety, were designed and synthesized for trackable gene delivery via optical imaging. All three amphiphiles exhibited ultralow critical micelle concentrations (CMCs) (up to 3.40 × 10^-6 M), prominent two-photon absorption properties, and solvatochromic fluorescence. Gel electrophoresis assays demonstrated that the migration of plasmid DNA was completely retarded after condensation with these gemini amphiphiles at low concentrations (up to 10 μM). In addition, the ester bond in these amphiphiles may facilitate vector degradation and DNA release, in response to esterase and the acidic environment inside cells. Upon self-assembly with DOPE to form liposomes, DEDPP-8/DOPE achieved the best transfection efficiency in four cell lines, and the transfection efficiency of DEDPP-8/DOPE in HeLa cell lines was 23.5-fold higher than that of Lipo2000, which is unusually high for small organic molecule-based nonviral vectors. Furthermore, excellent transfection efficiency of DEDPP-8/DOPE was obtained in the presence of serum, and the red fluorescence protein (RFP) gene was successfully transfected in zebrafish embryos. Both one- and two-photon fluorescence imaging clearly demonstrated the delivery process of plasmid DNA. This study demonstrated that gemini-type amphiphiles composed of a two-photon fluorophore core conjugated with triazole-[12]aneN₃ via an ester bond afforded an unprecedentedly high transfection efficiency with excellent biocompatibility, which may provide new insights for the design and development of multifunctional nonviral gene vectors for imageable gene delivery.

Review of the Biomolecular Modification of the Metal-Organ-Framework

Metal-organ frameworks (MOFs), as a kind of novel artificial material, have been widely studied in the field of chemistry. MOFs are capable of high loading capacities, controlled release, plasticity, and biosafety because of their porous structure and have been gradually functionalized as a drug carrier. Recently, a completely new strategy of combining biomolecules, such as oligonucleotides, polypeptides, and nucleic acids, with MOF nanoparticles was proposed. The synthetic bio-MOFs conferred strong protection and endowed the MOFs with particular biological functions. Biomolecular modification of MOFs to form bridges for communication between different subjects has received increased attention. This review will focus on bio-MOFs modification methods and discuss the advantages, applications, prospects, and challenges of using MOFs in the field of biomolecule delivery.

I-Motif-Based in Situ Bipedal Hybridization Chain Reaction for Specific Activatable Imaging and Enhanced Delivery of Antisense Oligonucleotides

The efficient and precise delivery of antisense oligonucleotides (ASOs) to target cells is of great value in gene silencing. However, the specificity and packaging capacity of delivery system still remains challenging. Here, we designed an i-motif forming-initiated in situ bipedal hybridization chain reaction (pH-Apt-BiHCR) amplification strategy for specific target cells imaging and enhanced gene delivery of ASOs. As a proof of concept, an 8-nt ASO modified with locked nucleic acid (LNA) which is complementary to the seed region of microRNA21 (miR-21) was used for gene silencing studies. Benefiting from the design of hairpin-contained i-motif, the stimuli-responsive assembly of pH-Apt-BiHCR was successfully achieved on MCF-7 cells surface based on the specific recognition of aptamer. Using this strategy, the pH-Apt-BiHCR not only contains repeated fluorescence resonance energy transfer (FRET) units for activatable tumor imaging with high contrast but also arrays with plenty of LNA ASOs as interference molecules for cancer cells inhibition. An in vitro assay showed that this strategy presented an excellent response ability in buffer within a narrow pH range (6.0-7.0) with a transition midpoint (pH^T) of 6.44 ± 0.06. Moreover, live cell studies revealed that it realized a specific activatable imaging of target cells, while the ASOs arrayed pH-Apt-BiHCR exhibited improved internalization via an endocytosis pathway and enhanced gene silencing to MCF-7 cells compared to single ASO alone. We believe that this design will inspire the development of novel probes for early diagnosis and therapy of cancer cells.

Encapsulation of Plasmid DNA by Nanoscale Metal-Organic Frameworks for Efficient Gene Transportation and Expression

The intracellular delivery and functionalization of genetic molecules play critical roles in gene-based theranostics. In particular, the delivery of plasmid DNA (pDNA) with safe nonviral vectors for efficient intracellular gene expression has received increasing attention; however, it still has some limitations. A facile one-pot method is employed to encapsulate pDNA into zeolitic imidazole framework-8 (ZIF-8) and ZIF-8-polymer vectors via biomimetic mineralization and coprecipitation. The pDNA molecules are found to be well distributed inside both nanostructures and benefit from their protection against enzymatic degradation. Moreover, through the use of a polyethyleneimine (PEI) 25 kD capping agent, the nanostructures exhibit enhanced loading capacity, better pH responsive release, and stronger binding affinity to pDNA. From in vitro experiments, the cellular uptake and endosomal escape of the protected pDNA are greatly improved with the superior ZIF-8-PEI 25 kD vector, leading to successful gene expression with high transfection efficacy, comparable to expensive commercial agents. New cost-effective avenues to develop metal-organic-framework-based nonviral vectors for efficient gene delivery and expression are provided.

Plasmid DNA Delivery: Nanotopography Matters

Plasmid DNA molecules with unique loop structures have widespread bioapplications, in many cases relying heavily on delivery vehicles to introduce them into cells and achieve their functions. Herein, we demonstrate that control over delicate nanotopography of silica nanoparticles as plasmid DNA vectors has significant impact on the transfection efficacy. For silica nanoparticles with rambutan-, raspberry-, and flower-like morphologies composed of spike-, hemisphere-, and bowl-type subunit nanotopographies, respectively, the rambutan-like nanoparticles with spiky surfaces demonstrate the highest plasmid DNA binding capability and transfection efficacy of 88%, higher than those reported for silica-based nanovectors. Moreover, it is shown that the surface spikes of rambutan nanoparticles provide a continuous open space to bind DNA chains via multivalent interactions and protect the gene molecules sheltered in the spiky layer against nuclease degradation, exhibiting no significant transfection decay. This unique protection feature is in great contrast to a commercial transfection agent with similar transfection performance but poor protection capability against enzymatic cleavage. Our study provides new understandings in the rational design of nonviral vectors for efficient gene delivery.

Gene editing of MPS I human fibroblasts by co-delivery of a CRISPR/Cas9 plasmid and a donor oligonucleotide using nanoemulsions as nonviral carriers

Mucopolysaccharidosis type I (MPS I) is an inherited disease caused by the deficiency of alpha-L-iduronidase (IDUA). This study shows the use of nanoemulsions co-complexed with the plasmid of CRISPR/Cas9 system and a donor oligonucleotide aiming at MPS I gene editing in vitro. Nanoemulsions composed of MCT, DOPE, DOTAP, DSPE-PEG, and water were prepared by high-pressure homogenization. The DNA was complexed by adsorption (NA) or encapsulation (NE) of preformed DNA/DOTAP complexes with nanoemulsions at +4/-1 charge ratio. The incubation in pure DMEM or supplemented with serum showed that the complexation with DNA was stable after 1 h of incubation, but the complexes tended to release the adsorbed DNA after 24 h of incubation, while the encapsulated DNA remained complexed in the oil core of the nanoemulsions even 48 h after incubation with DMEM. The treatment of MPS I patient's fibroblasts homozygous for the p.Trp402^∗ mutation led to a significant increase in IDUA activity at 2, 15, and 30 days when compared to MPS I untreated fibroblasts. Flow cytometry and confocal microscopy demonstrated that there was a reduction in the area of lysosomes to values similar to normal, an indicator of correction of the cellular phenotype. These results show that the nanoemulsions co-complexed with the CRISPR/Cas9 system and a donor oligonucleotide could effectively transfect MPS I p.Trp402^∗ patient's fibroblasts, as well as enable the production of IDUA, and represent a potential new treatment option for MPS I.

Factors influencing transfection efficiency of pIDUA/nanoemulsion complexes in a mucopolysaccharidosis type I murine model

Mucopolysaccharidosis type I (MPS I) is an autosomal disease caused by alpha-l-iduronidase (IDUA) deficiency. This study used IDUA knockout mice as a model to evaluate whether parameters such as dose of plasmid and time of treatment could influence the transfection efficiency of complexes formed with PEGylated cationic nanoemulsions and plasmid (pIDUA), which contains the gene that encodes for IDUA. Formulations were composed of medium chain triglycerides, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-(amino[polyethylene glycol]-2000), 1,2-dioleoyl-sn-glycero-3-trimethylammonium propane (DOTAP), glycerol, and water and were prepared by the adsorption or encapsulation of preformed pIDUA–DOTAP complexes by high-pressure homogenization. A progressive increase in IDUA expression was observed with an increase in the dose and time of transfection for mice treated with both complexes (adsorbed and encapsulated), especially in the liver. Regardless of the complex administered, a significant increase in IDUA activity was detected in lungs and liver compared with nontreated MPS I when a dose of 60 μg was administered and IDUA activity was measured 7 days postadministration. Tissue sections of major organs showed no presence of cell necrosis, inflammatory infiltrate, or an increase in apoptosis. Furthermore, immunohistochemistry for CD68 showed no difference in the number of macrophage cells in treated and nontreated animals, indicating the absence of inflammatory reaction caused by the treatment. The data set obtained in this study allowed establishing that factors such as dose and time can influence transfection efficiency in different degrees and that these complexes did not lead to any lethal effect in the MPS I murine model used.

Large-pore ultrasmall mesoporous organosilica nanoparticles: micelle/precursor co-templating assembly and nuclear-targeted gene delivery

A novel micelle/precursor co-templating assembly strategy is successfully developed to synthesize large-pore ultrasmall mesoporous organosilica nanoparticles (MONs). Furthermore, elaborately designed MONs with a cell-penetrating peptide (TAT) (MONs-PTAT) are constructed for highly efficient intranuclear gene delivery. They exhibit a high loading capacity, improved protection for the loaded gene, and enhanced transfection efficiencies of EGFP plasmid (pEGFP).

Therapeutic potential of adenovirus-mediated delivery of β-defensin 2 for experimental otitis media

Otitis media (OM), one of the most prevalent diseases in young children, is clinically important owing to its high incidence in children and its potential impact on language development and motor coordination. OM is the most common reason for the prescription of antibiotics (accounting for 25% of prescriptions) due to its extremely high incidence. A recent increase in antibiotic resistance among OM pathogens is emerging as a major public health concern globally, which led us to consider non-antibiotic approaches for the management of OM. In this study, we evaluated gene transfer of an antimicrobial peptide, human β-defensin 2 (DEFB4), using an adenoviral vector (Ad5 with deletions of E1/E3/E4) as a potential therapeutic approach. We demonstrated that the transduction of human β-defensin 2 induces the production of human β-defensin 2 and suppresses non-typeable Haemophilus influenzae (NTHi) adhesion to human middle ear epithelial cells. Moreover, intratympanic inoculation of Ad-DEFB4 was found to attenuate NTHi-induced middle ear effusions without eliciting a significant immune response. Most importantly, intratympanic inoculation of Ad-DEFB4 appeared to significantly augment clearance of NTHi from middle ear cavity. Collectively, our results suggest that intratympanic gene delivery of antimicrobial molecules may serve as an alternative/adjuvant approach for the management of OM.

Development of nucleic acid vaccines: use of self-amplifying RNA in lipid nanoparticles

Self-amplifying RNA or RNA replicon is a form of nucleic acid-based vaccine derived from either positive-strand or negative-strand RNA viruses. The gene sequences encoding structural proteins in these RNA viruses are replaced by mRNA encoding antigens of interest as well as by RNA polymerase for replication and transcription. This kind of vaccine has been successfully assayed with many different antigens as vaccines candidates, and has been shown to be potent in several animal species, including mice, nonhuman primates, and humans. A key challenge to realizing the broad potential of self-amplifying vaccines is the need for safe and effective delivery methods. Ideally, an RNA nanocarrier should provide protection from blood nucleases and extended blood circulation, which ultimately would increase the possibility of reaching the target tissue. The delivery system must then be internalized by the target cell and, upon receptor-mediated endocytosis, must be able to escape from the endosomal compartment into the cell cytoplasm, where the RNA machinery is located, while avoiding degradation by lysosomal enzymes. Further, delivery systems for systemic administration ought to be well tolerated upon administration. They should be safe, enabling the multiadministration treatment modalities required for improved clinical outcomes and, from a developmental point of view, production of large batches with reproducible specifications is also desirable. In this review, the concept of self-amplifying RNA vaccines and the most promising lipid-based delivery systems are discussed.

Probiotic technological and functional characteristics of Lactobacillus strains isolated from chicken gut

Lactobacillus spp. isolated from different portions of chickens' gastrointestinal tract were evaluated concerning their ability to survive in a water-in-oil (W/0) emulsion containing sesame and sunflower oil. After sixty days of emulsion storage under refrigeration, three of five strains tested survived in number equal to or higher than 10(6)cfu/g. Lactobacillus reuteri 2M14C, which presented the highest survival in W/O emulsion (10(7)cfu/g), was tested for its capacity to resist throughout the passage through gnotobiotic mice gastrointestinal tract and for the ability to stimulate murine peritoneal macrophages phagocytosis. This strain remained at a number above 10(9)cfu/g feces during ten days of monoassociation, and monoassociated mice showed phagocytic activity significantly greater than the germ-free controls (P<0.05). The results suggest that the formulation can be used to incorporate viable Lactobacillus spp. cells in animal feed. Moreover, the results suggest that L. reuteri 2M14C is a strong candidate to be incorporated in probiotic formulations for use in chicken.

Gene therapy and DNA delivery systems

Gene therapy is a promising new technique for treating many serious incurable diseases, such as cancer and genetic disorders. The main problem limiting the application of this strategy in vivo is the difficulty of transporting large, fragile and negatively charged molecules like DNA into the nucleus of the cell without degradation. The key to success of gene therapy is to create safe and efficient gene delivery vehicles. Ideally, the vehicle must be able to remain in the bloodstream for a long time and avoid uptake by the mononuclear phagocyte system, in order to ensure its arrival at the desired targets. Moreover, this carrier must also be able to transport the DNA efficiently into the cell cytoplasm, avoiding lysosomal degradation. Viral vehicles are the most commonly used carriers for delivering DNA and have long been used for their high efficiency. However, these vehicles can trigger dangerous immunological responses. Scientists need to find safer and cheaper alternatives. Consequently, the non-viral carriers are being prepared and developed until techniques for encapsulating DNA can be found. This review highlights gene therapy as a new promising technique used to treat many incurable diseases and the different strategies used to transfer DNA, taking into account that introducing DNA into the cell nucleus without degradation is essential for the success of this therapeutic technique.

Physical factors affecting plasmid DNA compaction in stearylamine-containing nanoemulsions intended for gene delivery

Cationic lipids have been used in the development of non-viral gene delivery systems as lipoplexes. Stearylamine, a cationic lipid that presents a primary amine group when in solution, is able to compact genetic material by electrostatic interactions. In dispersed systems such as nanoemulsions this lipid anchors on the oil/water interface confering a positive charge to them. The aim of this work was to evaluate factors that influence DNA compaction in cationic nanoemulsions containing stearylamine. The influence of the stearylamine incorporation phase (water or oil), time of complexation, and different incubation temperatures were studied. The complexation rate was assessed by electrophoresis migration on agarose gel 0.7%, and nanoemulsion and lipoplex characterization was done by Dynamic Light Scattering (DLS). The results demonstrate that the best DNA compaction process occurs after 120 min of complexation, at low temperature (4 ± 1 °C), and after incorporation of the cationic lipid into the aqueous phase. Although the zeta potential of lipoplexes was lower than the results found for basic nanoemulsions, the granulometry did not change. Moreover, it was demonstrated that lipoplexes are suitable vehicles for gene delivery.

Influence of phospholipid composition on cationic emulsions/DNA complexes: physicochemical properties, cytotoxicity, and transfection on Hep G2 cells

BACKGROUND

Cationic nanoemulsions have been recently considered as potential delivery systems for nucleic acids. This study reports the influence of phospholipids on the properties of cationic nanoemulsions/DNA plasmid complexes.

METHODS

Nanoemulsions composed of medium-chain triglycerides, stearylamine, egg lecithin or isolated phospholipids, ie, DSPC, DOPC, DSPE, or DOPE, glycerol, and water were prepared by spontaneous emulsification. Gene transfer to Hep G2 cells was analyzed using real-time polymerase chain reaction.

RESULTS

The procedure resulted in monodispersed nanoemulsions with a droplet size and zeta potential of approximately 250 nm and +50 mV, respectively. The complexation of cationic nanoemulsions with DNA plasmid, analyzed by agarose gel retardation assay, was complete when the complex was obtained at a charge ratio of ≥ 1.0. In these conditions, the complexes were protected from enzymatic degradation by DNase I. The cytotoxicity of the complexes in Hep G2 cells, evaluated by MTT assay, showed that an increasing number of complexes led to progressive toxicity. Higher amounts of reporter DNA were detected for the formulation obtained with the DSPC phospholipid. Complexes containing DSPC and DSPE phospholipids, which have high phase transition temperatures, were less toxic in comparison with the formulations obtained with lecithin, DOPC, and DOPE.

CONCLUSION

The results show the effect of the DNA/nanoemulsion complexes composition on the toxicity and transfection results.

ECM-based materials in cardiovascular applications: Inherent healing potential and augmentation of native regenerative processes

The in vivo healing process of vascular grafts involves the interaction of many contributing factors. The ability of vascular grafts to provide an environment which allows successful accomplishment of this process is extremely difficult. Poor endothelisation, inflammation, infection, occlusion, thrombosis, hyperplasia and pseudoaneurysms are common issues with synthetic grafts in vivo. Advanced materials composed of decellularised extracellular matrices (ECM) have been shown to promote the healing process via modulation of the host immune response, resistance to bacterial infections, allowing re-innervation and reestablishing homeostasis in the healing region. The physiological balance within the newly developed vascular tissue is maintained via the recreation of correct biorheology and mechanotransduction factors including host immune response, infection control, homing and the attraction of progenitor cells and infiltration by host tissue. Here, we review the progress in this tissue engineering approach, the enhancement potential of ECM materials and future prospects to reach the clinical environment.