Comparison of antisense oligonucleotide drug delivery systems

Cellular uptake and trafficking of peptide-based drug delivery systems for miRNA

Today, macromolecular compounds such as microRNAs (miRNAs) are becoming more and more widespread as leading therapeutics. However, their application is limited mostly due to their poor stability, limited cellular uptake, and poor target specificity. Cell-penetrating peptides (CPPs), a group of positively charged peptides, represent a breakthrough as delivery systems for macromolecules. In the present study, we used two types of nanoparticles which differ in the type of CPP used for their manufacturing. The first type is composed of protamine, an arginine rich CPP, which is highly positively charged. The arginine residues are able to form electrostatic interactions with miRNAs, stabilize them, and deliver them to cells. The second type is composed of the N-Ter peptide (also known as MPG), an amphipathic peptide rich in lysine. The positively charged parts of the N-Ter peptide electrostatically stabilize miRNAs, whereas its amphipathic character allows it to successfully traverse cell membranes. We used miRNA-27a, a negative regulator of adipogenesis, to form nanoparticles with the peptides and traced their uptake in 3T3-L1 preadipocytes. Motivated by the lengthy discourse regarding the uptake mechanism of CPPs, the focus of our study was to analyse and understand the internalization of proticles (protamine nanoparticles) and N-Ter complexes. The nanoparticles were characterized regarding size, size distribution, and zeta potential, and their cytotoxicity was tested in 3T3-L1 cells. The uptake studies were performed by varying the experimental conditions such as time, concentration, and temperature, as well as by applying different inhibitors of endocytosis. Furthermore, we assessed the biological effect of miRNA-27a on the pro-adipogenic machinery. The obtained data have shown that protamine and the N-Ter peptide form positively charged nanoparticles through non-covalent complexation. The uptake of proticles and N-Ter complexes was found to be dependent on time, concentration, and temperature, and different uptake pathways were discovered to be involved in the internalization of the different nanoparticles. Furthermore, both types of nanoparticles induced the anti-adipogenic effect of miRNA-27a, demonstrating that this approach can be used as a novel miRNA replacement therapy in the treatment of obesity and obesity-related disorders.

An In Vitro Evaluation of Selenium Nanoparticles on Osteoblastic Differentiation and Antimicrobial Properties against Porphyromonas gingivalis

Despite numerous treatment methods, there is no gold standard for the treatment of peri-implantitis—an infectious peri-implant disease. Here, we examined selenium nanoparticles (SeNPs) at a wide range of concentrations to investigate their cytotoxicity, regulation of osteoblastic differentiation, and assessed the antibacterial effect against Porphyromonas gingivalis. SeNPs (mean size: 70 nm; shape: near-spherical; concentration: 0–2048 ppm) were tested against the MC3T3-E1 osteoblast precursor cell line and P. gingivalis red complex pathogen. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) analysis was used to evaluate the bone morphogenetic protein 2 (BMP-2) signaling pathway. SeNPs at concentrations of 2–16 ppm showed no obvious cytotoxicity and promoted good mineralization and calcification. SeNPs at concentrations 64 ppm and below influenced gene expression promoting osteoblastic differentiation, whereas at high concentrations inhibited the expression of Runt-related transcription factor 2 (Runx2). The growth of P. gingivalis was significantly inhibited at SeNP concentrations of more than 4 ppm. SeNPs at low concentrations promoted osteoblastic differentiation while strongly inhibiting peri-implantitis pathogen growth. This study represents one of the few in vitro assessments of SeNPs against a red complex pathogen and the regulatory effect on osteoblastic differentiation. The findings demonstrate SeNPs could potentially be used for future application on implant coating.

U7 snRNA: A tool for gene therapy

Most U-rich small nuclear ribonucleoproteins (snRNPs) are complexes that mediate the splicing of pre-mRNAs. U7 snRNP is an exception in that it is not involved in splicing but is a key factor in the unique 3' end processing of replication-dependent histone mRNAs. However, by introducing controlled changes in the U7 snRNA histone binding sequence and in the Sm motif, it can be used as an effective tool for gene therapy. The modified U7 snRNP (U7 Sm OPT) is thus not involved in the processing of replication-dependent histone pre-mRNA but targets splicing by inducing efficient skipping or inclusion of selected exons. U7 Sm OPT is of therapeutic importance in diseases that are an outcome of splicing defects, such as myotonic dystrophy, Duchenne muscular dystrophy, amyotrophic lateral sclerosis, β-thalassemia, HIV-1 infection and spinal muscular atrophy. The benefits of using U7 Sm OPT for gene therapy are its compact size, ability to accumulate in the nucleus without causing any toxic effects in the cells, and no immunoreactivity. The risk of transgene misregulation by using U7 Sm OPT is also low because it is involved in correcting the expression of an endogenous gene controlled by its own regulatory elements. Altogether, using U7 Sm OPT as a tool in gene therapy can ensure lifelong treatment, whereas an oligonucleotide or other drug/compound would require repeated administration. It would thus be strategic to harness these unique properties of U7 snRNP and deploy it as a tool in gene therapy.

Aptamer-Equipped Protamine Nanomedicine for Precision Lymphoma Therapy

Anaplastic large cell lymphoma (ALCL) is the most common T-cell lymphoma in children. ALCL cells characteristically express surface CD30 molecules and carry the pathogenic ALK oncogene, both of which are diagnostic biomarkers and are also potential therapeutic targets. For precision therapy, we report herein a protamine nanomedicine incorporated with oligonucleotide aptamers to selectively target lymphoma cells, a dsDNA/drug payload to efficiently kill targeted cells, and an siRNA to specifically silence ALK oncogenes. The aptamer-equipped protamine nanomedicine was simply fabricated through a non-covalent charge-force reaction. The products had uniform structure morphology under an electron microscope and a peak diameter of 103 nm by dynamic light scattering measurement. Additionally, flow cytometry analysis demonstrated that under CD30 aptamer guidance, the protamine nanomedicine specifically bound to lymphoma cells, but did not react to off-target cells in control experiments. Moreover, specific cell targeting and intracellular delivery of the nanomedicine were also validated by electron and confocal microscopy. Finally, functional studies demonstrated that, through combined cell-selective chemotherapy using a drug payload and oncogene-specific gene therapy using an siRNA, the protamine nanomedicine effectively killed lymphoma cells with little toxicity to off-target cells, indicating its potential for precision therapy.

Comparison of PEGylated and non-PEGylated proticles: An in vitro and in vivo study

The development of so-called Proticles opens attractive possibilities for new drug delivery systems. Proticles are nanoparticles (NPs), which are formed by self-assembly of negatively charged oligonucleotides in combination with the positively charged peptide protamine. Polyethylene glycol (PEG) is a widely known pharmaceutical agent to stop particle growth and prolong circulation half-life of drug delivery systems. Therefore, two different NP formulations - one PEGylated and one non-PEGylated - were used in this work to gain information about the biological stability and half-life in circulation of Proticles. Thus, this study presents data of in vitro stability and in vivo pharmacokinetics of both, non-PEGylated and PEGylated Proticles radiolabeled with ¹¹¹InCl₃. The study demonstrated that successful radiolabeling of both Proticle-formulations was performed resulting in high radiochemical yields (> 85 %). Furthermore, the influence of PEGylation on the in vitro stability of ¹¹¹In-radiolabeled NPs was investigated. No significant difference due to PEGylation was found. Unlike in vitro results, non-PEGylated ¹¹¹In-Proticles seemed to degrade faster in vivo than PEGylated ¹¹¹In-proticles, resulting in significantly higher blood values (¹¹¹In-PEG-proticles: 0.23 ± 0.01 % ID/g 1 h p.i.; ¹¹¹In-proticles: 0.06 ± 0.01 % ID/g 1 h p.i.; p < 0.05). Visualized by SPECT imaging urinary excretion represented the major pathway of elimination for both NP-formulations. In conclusion, this study provides data indicating a positive influence of PEG-derivatization on the biodistribution and pharmacokinetics of Proticles. These results form the basis for further developments as drug delivery and active drug targeting devices.

Lipoprotein-Related and Apolipoprotein-Mediated Delivery Systems for Drug Targeting and Imaging

The integration of lipoprotein-related or apolipoprotein-targeted nanoparticles as pharmaceutical carriers opens new therapeutic and diagnostic avenues in nanomedicine. The concept is to exploit the intrinsic characteristics of lipoprotein particles as being the natural transporter of apolar lipids and fat in human circulation. Discrete lipoprotein assemblies and lipoprotein-based biomimetics offer a versatile nanoparticle platform that can be manipulated and tuned for specific medical applications. This article reviews the possibilities for constructing drug loaded, reconstituted or artificial lipoprotein particles. The advantages and limitations of lipoproteinbased delivery systems are critically evaluated and potential future challenges, especially concerning targeting specificity, concepts for lipoprotein rerouting and design of innovative lipoprotein mimetic particles using apolipoprotein sequences as targeting moieties are discussed. Finally, the review highlights potential medical applications for lipoprotein-based nanoparticle systems in the fields of cardiovascular research, cancer therapy, gene delivery and brain targeting focusing on representative examples from literature.

Protamine-oligonucleotide-nanoparticles: Recent advances in drug delivery and drug targeting

Application of oligonucleotides as active compounds has become a crucial field of pharmaceutical research in recent years. In order to improve inadequate transfection rate and to avoid rapid enzymatic degradation of antisense oligonucleotides (AS-ODNs) a novel nanoparticulate delivery system was reported by our group at the beginning of 2000. AS-ODNs are condensed by the polycationic peptide protamine into solid particles in the size range of 100-200nm. Nanoparticle formation is driven by a self-assembling process based on electrostatic interactions between the oppositely charged biomolecules. This new delivery system was named "proticles" and showed very efficient protection against enzymatic digestion, high transfection rates and significant antisense effects in vitro. Throughout broader research, this promising approach was enlarged, and AS-ODNs were replaced by siRNA or CpG-oligonucleotides to address the aspect of immune-modulation and vaccination. More recent studies on proticles verified upscaling of the self-assembling process as well as the potential of proticle formulations for active drug targeting, like tumor- or atherosclerotic plaque targeting. Thereby also the application for diagnostic purposes was emphasized. This review will focus on the characterization of the nucleoprotein protamine as well as on the variety of possible nucleotides/peptides which were already assembled into the proticle matrix. Furthermore it will provide an insight into the broad area of application where proticles can present a valuable tool for successful oligonucleotide delivery.

Human immunodeficiency virus-1 (HIV-1)-mediated apoptosis: new therapeutic targets

HIV has posed a significant challenge due to the ability of the virus to both impair and evade the host’s immune system. One of the most important mechanisms it has employed to do so is the modulation of the host’s native apoptotic pathways and mechanisms. Viral proteins alter normal apoptotic signaling resulting in increased viral load and the formation of viral reservoirs which ultimately increase infectivity. Both the host’s pro- and anti-apoptotic responses are regulated by the interactions of viral proteins with cell surface receptors or apoptotic pathway components. This dynamic has led to the development of therapies aimed at altering the ability of the virus to modulate apoptotic pathways. These therapies are aimed at preventing or inhibiting viral infection, or treating viral associated pathologies. These drugs target both the viral proteins and the apoptotic pathways of the host. This review will examine the cell types targeted by HIV, the surface receptors exploited by the virus and the mechanisms whereby HIV encoded proteins influence the apoptotic pathways. The viral manipulation of the hosts’ cell type to evade the immune system, establish viral reservoirs and enhance viral proliferation will be reviewed. The pathologies associated with the ability of HIV to alter apoptotic signaling and the drugs and therapies currently under development that target the ability of apoptotic signaling within HIV infection will also be discussed.

Polybutylcyanoacrylate nanoparticle-mediated neurotrophin-3 gene delivery for differentiating iPS cells into neurons

Guided neuronal differentiation of induced pluripotent stem cells (iPSCs) with genetic regulation is an important issue in biomedical research and in clinical practice for nervous regeneration and repair. To enhance the intracellular delivery of plasmid DNA (pDNA), polybutylcyanoacrylate (PBCA) nanoparticles (NPs) were employed to mediate the transport of neurotrophin-3 (NT-3) into iPSCs. The ability of iPSCs to differentiate into neuronal lineages was shown by immunofluorescent staining, western blotting, and flow cytometry. By transmission electron microscopy, we found that PBCA NPs could efficiently grasp pDNA, thereby increasing the particle size and conferring a negative surface charge. In addition, the treatments with PBCA NP/NT-3 complexes enhanced the expression of NT-3, TrkC, NH-H, NSE, and PSD95 by differentiating iPSCs. Neurons produced from iPSCs were incapable of returning to pluripotency, demonstrating with a series of differentiation scheme for adipogenesis and osteogenesis. The pretreatment with PBCA NP/NT-3 complexes can be one of critical biotechnologies and effective delivery systems in gene transfection to accelerate the differentiation of iPSCs into neurons.

A calcium phosphate nanoparticle-based biocarrier for efficient cellular delivery of antisense oligodeoxynucleotides

Antisense oligodeoxynucleotides (ASODNs) can bind to some specific RNA of survivin can prevent the mRNA translation at the genetic level, which will inhibit survivin expression and make the cancer cells apoptosis. However, the ASODNs-based therapies are hampered by their instability to cellular nuclease and their weak intracellular penetration. Here we reported a calcium phosphate (CP)-based carrier to achieve efficient delivery of ASODNs into cells. In this study, we used a facile microemulsion approach to prepare spherical and porous ASODNs-CP nanoparticles (ASODNS-CPNPs) with the size of 50-70 nm in diameter, and their structure, morphology and composition were characterized by TEM, XRD, FTIR, ICP and DLS, UV-Vis spectroscopy and agarose gel electrophoresis. The results indicated that the nanoparticles have a high ASODNs loading capacity. Furthermore, cellular uptake and delivery efficiency of the ASODNS-CPNPs, as well as cellular apoptosis induced by the ASODNs doping into the calcium phosphate nanoparticles, were investigated by confocal laser scanning microscopy, biological TEM, flow cytometry, and MTT assay. Efficient intracellular delivery of the nanoparticles was observed. All these results suggested that the prepared calcium phosphate nanoparticles could be used as a promising biocarrier for delivery of ASODNs.

Formulation Strategies, Characterization, and In Vitro Evaluation of Lecithin-Based Nanoparticles for siRNA Delivery

The aim of the present work was to take advantage of lecithin's biocompatibility along with its physicochemical properties for the preparation of lecithin-based nanocarriers for small interfering RNA (siRNA) delivery. Water lecithin dispersions were prepared in different conditions, loaded with siRNA at different N/P ratios, and evaluated for loading capacity. The most appropriate ones were then assayed for cytotoxicity and characterized in terms of particle size distribution, zeta potential, and morphology. Results demonstrated that formulations prepared at pH 5.0 and 7.0 were able to load siRNA at broad N/P ratios, and cellular uptake assays showed an efficient delivery of oligos in MCF-7 human breast cancer cells; fluorescent-labeled dsRNA mainly located next to its target, near the nucleus of the cells. No signs of toxicity were observed for broad compositions of lecithin. The physicochemical characterization of the siRNA-loaded dispersions exhibited particles of nanometric sizes and pH-dependant shapes, which make them suitable for ex vivo and in vivo further evaluation.

Effects of decoy molecules targeting NF-kappaB transcription factors in Cystic fibrosis IB3-1 cells: recruitment of NF-kappaB to the IL-8 gene promoter and transcription of the IL-8 gene

One of the clinical features of cystic fibrosis (CF) is a deep inflammatory process, which is characterized by production and release of cytokines and chemokines, among which interleukin 8 (IL-8) represents one of the most important. Accordingly, there is a growing interest in developing therapies against CF to reduce the excessive inflammatory response in the airways of CF patients. Since transcription factor NF-kappaB plays a critical role in IL-8 expression, the transcription factor decoy (TFD) strategy might be of interest. In order to demonstrate that TFD against NF-kappaB interferes with the NF-kappaB pathway we proved, by chromatin immunoprecipitation (ChIP) that treatment with TFD oligodeoxyribonucleotides of cystic fibrosis IB3–1 cells infected with Pseudomonas aeruginosa leads to a decrease occupancy of the Il-8 gene promoter by NF-kappaB factors. In order to develop more stable therapeutic molecules, peptide nucleic acids (PNAs) based agents were considered. In this respect PNA-DNA-PNA (PDP) chimeras are molecules of great interest from several points of view: (1) they can be complexed with liposomes and microspheres; (2) they are resistant to DNases, serum and cytoplasmic extracts; (3) they are potent decoy molecules. By using electrophoretic mobility shift assay and RT-PCR analysis we have demonstrated that (1) the effects of PDP/PDP NF-kappaB decoy chimera on accumulation of pro-inflammatory mRNAs in P.aeruginosa infected IB3–1 cells reproduce that of decoy oligonucleotides; in particular (2) the PDP/PDP chimera is a strong inhibitor of IL-8 gene expression; (3) the effect of PDP/PDP chimeras, unlike those of ODN-based decoys, are observed even in the absence of protection with lipofectamine. These informations are of great impact, in our opinion, for the development of stable molecules to be used in non-viral gene therapy of cystic fibrosis.

Adhesion, phenotypic expression, and biosynthetic capacity of corneal keratocytes on surfaces coated with hyaluronic acid of different molecular weights

In ophthalmology, hyaluronic acid (HA) is an important extracellular matrix (ECM) component and is appropriate for use in generating a microenvironment for cell cultivation. The aim of this work was to evaluate the rabbit corneal keratocyte (RCK) growth in response to HA coatings under serum-free conditions. After modification with HA of varying molecular weights (MWs: 35-1500kDa), the surfaces were characterized by atomic force microscopy and contact angle measurements, and were used for cell culture studies. Our data indicated that the substrates coated with higher negatively charged HA become rougher and are more hydrophilic, resulting in the decrease of cell adhesion and cell-matrix interaction. This early cellular event was likely responsible for the determination of keratocyte configuration. Additionally, for the growth of RCKs on dry HA coatings with surface roughness of 1.1-1.7 nm, a strong cell-cell interaction was observed, which may facilitate the formation of multicellular spheroid aggregates and maintenance of mitotically quiescent state. At each culture time point from 1 to 5 days, a better biosynthetic capacity associated with a higher prevalence of elevated ECM production was found for the cells in a spherical configuration. Irrespective of polysaccharide MW of surface coatings, the RCKs presented good viability without hypoxia-induced death. As compared with a monolayer of adherent keratocytes on tissue culture polystyrene plates and low MW HA-modified samples, the cell spheroids (76-110 μm in diameter) showed significantly higher expressions of keratocan and lumican and lower expressions of biglycan, similar to those of keratocytes in vivo. Moreover, the expression levels of corneal crystallin aldehyde dehydrogenase (7-9-fold increase) and nestin (10-16-fold increase) were greater in larger-sized spheroids, indicating higher ability to maintain cellular transparency and self-renewal potential. It is concluded that the cultured RCKs on surfaces coated with HA of different MWs can sense ECM cues, and the multicellular spheroids may potentially be used for corneal stromal tissue engineering applications.

Localized delivery of antisense oligonucleotides by cationic hydrogel suppresses TNF-α expression and endotoxin-induced osteolysis

PURPOSE

To investigate the possibility of using localized nucleic drug delivery methods for the treatment of osteolysis-related bone disease.

METHODS

A bio-degradable cationic hydrogel composed of gelatin and chitosan was used to deliver an antisense oligonucleotide (ASO) targeting murine TNF-α for the treatment of endotoxin-induced osteolysis.

RESULTS

ASO combined with this hydrogel was released when it was digested by adhering cells. The released ASO was efficiently delivered into contacted cells and tissues in vitro and in vivo. When tested in animal models of edotoxin-induced bone resorption, ASO delivered by such means effectively suppressed the expression of TNF-α and subsequently the osteoclastogenesis in vivo. Osteolysis in the edotoxin-induced bone resorption animal models was blocked by the treatment.

CONCLUSION

This is a successful attempt to apply localized gene delivery method to treat inflammatory diseases in vivo.

Biodistribution of antisense nanoparticles in mammary carcinoma rat model

Efficient and specific delivery of antisenses (ASs) and protection of the sequences from degradation are critical factors for effective therapy. Sustained release nanoparticles (NP) offer increased resistance to nuclease degradation, increased amounts of AS uptake, and the possibility of control in dosing and sustained duration of AS administration. The biodegradable and biocompatible poly(D,L-lactic-co-glycolic acid) copolymer (PLGA) was utilized to encapsulate AS directed against osteopontin (OPN), which is a promising therapeutic target in mammary carcinoma. Whole body biodistribution of OPN AS NP was evaluated in comparison to naked AS, in intact and mammary carcinoma metastasis model bearing rats. Naked and NP encapsulated AS exhibited different biodistribution profiles. AS NP, in contrast to naked AS, tended to accumulate mostly in the spleen, liver, and at the tumor inoculation site. Drug levels in intact organs were negligible. The elimination of naked AS was faster, due to rapid degradation of the unprotected sequence. It is concluded that AS NP protect the AS from degradation, provide efficient AS delivery to the tumor tissue, and minimize AS accumulation in intact organs due to the AS sustained release profile as well as the favorable NP physicochemical properties.

Mixed backbone antisense glucosylceramide synthase oligonucleotide (MBO-asGCS) loaded solid lipid nanoparticles: in vitro characterization and reversal of multidrug resistance in NCI/ADR-RES cells

In this study, solid lipid nanoparticles (SLN) loaded with MBO-asGCS oligonucleotide were prepared, characterized and evaluated for cytotoxicity against NCI/ADR-RES human ovary cancer cells. Two types of cetyltrimethyl ammonium bromide (CTAB) stabilized SLN, with or without ceramide VI, were prepared by mixed homogenization/ultrasonication technique. Complexes were characterized for size, zeta-potential, and stability in biorelevant media and against DNaseI activity. Binding and release studies were further confirmed by gel electrophoresis. Cytotoxicity of the SLN against NCI/ADR-RES cells was evaluated by quantizing ATP. SLN with ceramide VI had lower particle size (74.6 nm) with improved stability in RPMI media when compared to reference SLN without ceramide VI (167.16 nm). Both SLN however had similar cytotoxicity profile with an optimum binding at CTAB to MBO-asGCS ratio of 6:1. Blank SLN, and free MBO-asGCS in the presence and absence of free doxorubicin had insignificant effect on the viability of NCI/ADR-RES cells. However, when cells were concurrently treated with MBO-asGCS loaded SLN and free doxorubicin, cell viability significantly decreased to approximately 12%. These results suggested that SLN enhanced internalization and uptake of MBO-asGCS oligonucleotide, which led to the downregulation of GCS and subsequently reversing the resistance of the cells to doxorubicin.

Decoy oligodeoxyribonucleotides and peptide nucleic acids-DNA chimeras targeting nuclear factor kappa-B: inhibition of IL-8 gene expression in cystic fibrosis cells infected with Pseudomonas aeruginosa

Cystic fibrosis (CF) is characterized by a deep inflammatory process, with production and release of cytokines and chemokines, among which interleukin 8 (IL-8) represents one of the most important. Accordingly, there is a growing interest in developing therapies against IL-8, with the aim of reducing the excessive inflammatory response in the airways of CF patients. Since transcription factor NF-kappaB plays a critical role in IL-8 expression, the transcription factor decoy (TFD) strategy might be of interest. TFD is based on biomolecules mimicking the target sites of transcription factors (TFs) and able to interfere with TF activity when delivered to target cells. Here, we review the inhibitory effects of decoy oligodeoxyribonucleotides (ODNs) on expression of IL-8 gene and secretion of IL-8 by cystic fibrosis cells infected by Pseudomonas aeruginosa. In addition, the effects of decoy molecules based on peptide nucleic acids (PNAs) are discussed. In this respect PNA-DNA-PNA (PDP) chimeras are interesting: (a) unlike PNAs, they can be complexed with liposomes and microspheres; (b) unlike oligodeoxyribonucleotides (ODNs), they are resistant to DNAses, serum and cytoplasmic extracts; (c) unlike PNA/PNA and PNA/DNA hybrids, they are potent decoy molecules. Interestingly, PDP/PDP NF-kappaB decoy chimeras inhibit accumulation of pro-inflammatory mRNAs (including IL-8 mRNA) in P. aeruginosa infected IB3-1, cells reproducing the effects of decoy oligonucleotides. The effects of PDP/PDP chimeras, unlike ODN-based decoys, are observed even in absence of protection with lipofectamine. Since IL-8 is pivotal in pro-inflammatory processes affecting cystic fibrosis, inhibition of its functions might have a clinical relevance.

Characterization of nickel-decorated PLGA particles anchored with a his-tagged polycation

The pharmacological impact of oligodeoxynucleotides (ODN) as transcription factors decoys (anti-sense) depends on the efficiency of cellular uptake. In this study, we sought to generate nickel-decorated particles to facilitate the entry of ODN into dendritic cells (DCs), the primary instigators of immune responses. Nickel ions were incorporated into the matrix of poly(D,L-lactide-co-glycolide) (PLGA) particles using the metal chelating lipid DOGS-NTA-Ni. Submicrometer-sized PLGA particles containing nickel ions (PLGA-Ni) were formed using a double-emulsion solvent evaporation method. Infrared spectroscopy provided chemical proofs of nickel incorporation into the PLGA matrix. Binding of the polycation O10H6 raised the surface potential of PLGA-Ni from -17 mV to +13 mV. This change was partially reserved by the presence of free imidazole, suggesting the binding was mediated by nickel-histidine coordination. When compared to PLGA particles without nickel, ODN bound to O10H6-coated PLGA-Ni particles exhibited enhanced capacity to accumulate in DCs cultured in vitro. DCs exhibited cellular stress after exposure to PLGA-Ni complexed with O10H6 and DNA, but this effect can be prevented by serum and was reversed overnight. These data suggest PLGA-Ni should be further explored as a nucleic acid carrier in the context of anti-sense gene down-regulation.

Controlled delivery of antisense oligonucleotides: a brief review of current strategies

Antisense therapy has been investigated extensively over the past two decades, either experimentally for gene functional research or clinically as therapeutic agents owing to the conceptual simplicity, ease of design and low cost. The concept of this therapeutic approach is promising because short antisense oligonucleotides (ASOs) can be delivered into target cells for specific hybridisation with target mRNA, resulting in the inhibition of the expression of pathogenic genes. However, the efficient delivery of the ASO molecules into target cells remains challenging; this bottleneck together with several other technical hurdles need to be overcome before this approach becomes effective and widely adopted. A variety of vectors such as lipids, polymers, peptides and nanoparticles have been explored. This review outlines the recent advances of the non-viral ASO delivery strategies. Several recent scientific studies, including authors' contributions, have been selected to highlight the technical aspects of ASO delivery.

Connexin43 antisense oligodeoxynucleotide treatment down-regulates the inflammatory response in an in vitro interphase organotypic culture model of optic nerve ischaemia

Using a model of optic nerve ischaemia, this study investigated oxygen-glucose deprivation (OGD) on isolated rat optic nerve segments cultured in vitro. Thereafter, the effect of antisense oligodeoxynucleotides (ASODN) specific to the gap junction protein connexin43 (Cx43) was evaluated in this same model. Following exposure to OGD for 2 hours, optic nerves were maintained in interphase organotypic culture with and without exposure to Cx43 ASODN. Optic nerves were sectioned at 2 hours, 6 hours, and at days 1, 2, 3 and 6 following culture. Cell death was quantified using propidium iodide (PI) staining and specific markers for Cx43, capillaries (von Willebrand factor), astrocytes (glial fibrillary acidic protein), microglia and endothelial cells (isolectin B4) were used to evaluate these parameters in conjunction with digital light and confocal microscopy. In this model, up-regulation of Cx43 was seen at 2 hours following exposure of the optic nerve to OGD and peaked at day 3. Cx43 ASODN treatment dampened this up-regulation. Additionally, more PI labeled cells were found in the centre of control optic nerve segments than in treated nerves (p<0.01). Controls also showed evidence of capillary breakdown and increased numbers of astrocytes and activated microglia compared to Cx43 ASODN treated nerves (p<0.05). Thus, the application of Cx43 ASODN to post-ischaemic optic nerve segments significantly reduced the up-regulation of Cx43 and, subsequently, the spread of injury and a resultant inflammatory response. Cx43 up-regulation may play an important role in optic nerve injury, offering a potential avenue for treatment in optic neuropathy.

Apolipoprotein A-I coating of protamine-oligonucleotide nanoparticles increases particle uptake and transcytosis in an in vitro model of the blood-brain barrier

Drug delivery to the brain is severely restricted by formation of tight junctions between adjacent brain capillary endothelial cells (BCEC). In the present study we have evaluated the effects of protamine-oligonucleotide nanoparticles (proticles) on the functional properties of primary porcine BCEC and characterized uptake and transcytosis of proticles by these cells. Proticles had no adverse effects on BCEC properties relevant to blood-brain barrier (BBB) function. Transcytosis of (125)I-labeled proticles across polarized BCEC cultures occurred in a time- and concentration-dependent manner. As apolipoproteins were suggested to enhance cellular proticle uptake, proticle coating was performed with apoA-I, the major apolipoprotein component of high density lipoproteins. Adsorption of apoA-I on the surface of proticles resulted in significantly improved uptake and transcytosis properties as compared to uncoated proticles. ApoA-I coating enhanced proticle delivery to astrocytes in an in vitro model of the BBB almost twofold. Blocking of scavenger receptor class B, type I (the prime receptor for high density lipoprotein/apoA-I that is expressed on BCEC) reduced transcytosis of apoA-I-coated proticles to levels observed for uncoated proticles. Our data indicate that apoA-I-coating of proticles could be a feasible targeting technology to improve delivery across the BBB.

Mechanisms of co-modified liver-targeting liposomes as gene delivery carriers based on cellular uptake and antigens inhibition effect

In order to deliver antisense oligonucleotides (asODN) into hepatocytes orientedly in the treatment of hepatitis B virus (HBV) infection, the liver-targeting cationic liposomes was developed as a gene carrier, which was co-modified with the ligand of the asialoglycoprotein receptor (ASGPR), beta-sitosterol-beta-d-glucoside (sito-G) and the nonionic surfactant, Brij 35. Flow cytometry (FCM) analysis and enzyme-linked immunosorbent assay (ELISA) showed that the asODN-encapsulating cationic liposomes exhibited high transfection efficiency and strong antigens inhibition effect in primary rat hepatocytes and HepG2.2.15 cells, respectively. With the help of several inhibitors acting on different steps during the targeting lipofection, the cellular uptake mechanisms of the co-modified liver-targeting cationic liposomes were investigated through antigens inhibition effect assay and confocal laser scanning microscopy (CLSM) analysis. The cellular uptake with high transfection efficiency seemed to involve both endocytosis and membrane fusion. The ligand sito-G was confirmed to be able to enhance ASGPR-mediated endocytosis, the nonionic surfactant Brij 35 seemed to be able to facilitate membrane fusion, and the co-modification resulted in the most efficient transfection but no enhanced cytotoxicity. These results suggested that the co-modified liver-targeting cationic liposomes would be a specific and effective carrier to transfer asODN into hepatocytes infected with HBV orientedly.

Innovative nanotechnologies for the delivery of oligonucleotides and siRNA

One way to reach intracellular therapeutic targets in cells consists in the use of short nucleic acids which will bind specifically to on targets thanks to either Watson-Crick base pairing or protein nucleic acids recognition rules. Among these short nucleic acids an important class of therapeutic agents is antisense oligonucleotides and siRNAs. However, the major problem of nucleic acids is their poor stability in biological media. One method, among others, to solve the stability problem is the use of colloïdal carriers such as nanoparticles. Nanoparticles have already been applied with success to in vitro drug delivery to particular types of cells and in vivo in several experimental models. Many membrane and intracellular processes deal with nanosized structure (typically 100 nm) which are processed further through the recognition sites of receptors and enzymes. Thus non-viral nanoparticles are interesting candidates to present biochemical molecules such as nucleic acids and proteins to cells as well as to protect them in vivo during delivery. This review focuses on the recent developments in the design of nanotechnologies to improve the delivery of antisense oligonucleotides and siRNAs.

Improving membrane activity of oligonucleotides by cetylpyridinium chloride: an electrochemical study

The interaction of phospholipid membranes and oligonucleotides complexed with a positively charged surfactant is reported. Phospholipid membranes were assembled at the interface between an immobilized organic phase and an aqueous phase using the Langmuir-Blodgett (L-B) technique. The interaction and adsorption of the naked oligonucleotides and oligonucleotides complexed with cetylpyridinium chloride (CP) was studied electrochemically using cyclic voltammetry (CV) and ac-voltammetry. Interfacial capacitance, obtained indirectly from ac-voltammetry as a function of interfacial potential, was fitted to the theory based on the solution of the Poisson-Boltzmann equation. It was shown that both types of naked oligonucleotides (phosphoromonothioates and phosphodiesters) adsorb on the lipid monolayers poorly. The introduction of CP to the system increases the adsorption efficiency significantly. However, one phosphoromonothioate appeared to form a compact globule with CP instead of adsorbing to the lipid membrane. These results demonstrate that electrochemical methods are a powerful tool for probing the behavior of drugs in the vicinity of model cell membranes.

Poly(propylacrylic acid) enhances cationic lipid-mediated delivery of antisense oligonucleotides

The use of antisense oligodeoxynucleotides (ODNs) to inhibit the expression of specific mRNA targets represents a powerful technology for control of gene expression. Cationic lipids and polymers are frequently used to improve the delivery of ODNs to cells, but the resulting complexes often aggregate, bind to serum components, and are trafficked poorly within cells. We show that the addition of a synthetic, pH-sensitive, membrane-disrupting polyanion, poly(propylacrylic acid) (PPAA), improves the in vitro efficiency of the cationic lipid, DOTAP, with regard to oligonucleotide delivery and antisense activity. In characterization studies, ODN complexation with DOTAP/ODN was maintained even when substantial amounts of PPAA were added. The formulation also exhibited partial protection of phosphodiester oligonucleotides against enzymatic digestion. In Chinese hamster ovary (CHO) cells, incorporation of PPAA in DOTAP/ODN complexes improved 2- to 3-fold the cellular uptake of fluorescently tagged oligonucleotides. DOTAP/ODN complexes containing PPAA also maintained high levels of uptake into cells upon exposure to serum. Addition of PPAA to DOTAP/ODN complexes enhanced the antisense activity (using GFP as the target) over a range of PPAA concentrations in both serum-free, and to a lesser extent, serum-containing media. Thus, PPAA is a useful adjunct that improves the lipid-mediated delivery of oligonucleotides.

Animal models of behavioral dysfunctions: Basic concepts and classifications, and an evaluation strategy

In behavioral neurosciences, such as neurobiology and biopsychology, animal models make it possible to investigate brain-behavior relations, with the aim of gaining insight into normal and abnormal human behavior and its underlying neuronal and neuroendocrinological processes. Different types of animal models of behavioral dysfunctions are reviewed in this article. In order to determine the precise criteria that an animal model should fulfill, experts from different fields must define the desired characteristics of that model at the neuropathologic and behavioral level. The list of characteristics depends on the purpose of the model. The phenotype-abnormal behavior or behavioral dysfunctions-has to be translated into testable measures in animal experiments. It is essential to standardize rearing, housing, and testing conditions, and to evaluate the reliability, validity (primarily predictive and construct validity), and biological or clinical relevance of putative animal models of human behavioral dysfunctions. This evaluation, guided by a systematic strategy, is central to the development of a model. The necessity of animal models and the responsible use of animals in research are discussed briefly.

Cellular uptake of phosphorothioate oligonucleotide facilitated by cationic porphyrin: a microfluorescence study

Cationic 5,10,15,20-tetrakis (1-methyl-4-pyridyl) porphyrin was tested as a delivery agent for oligonucleotides. By using fluorescence microimaging, it has been shown that complexation of the porphyrin to the phosphorothioate analog of dT(15) labeled by rhodamine enabled its nonendocytic penetration into the cell and regular distribution in the cytoplasm and preferentially into the nucleus. Time-resolved microfluorescence spectroscopy revealed that the oligonucleotide integrity was kept. A small fraction of the porphyrin molecules seems to undergo change of the binding mode after internalization, probably due to duplex formation between the oligonucleotide and its cellular target sequences, or due to dissociation of the porphyrin from the oligonucleotide and subsequent interactions in the cellular environment.

Efficient delivery of a Bcl-2-specific antisense oligodeoxyribonucleotide (G3139) via transferrin receptor-targeted liposomes

A novel transferrin receptor (TfR)-targeted liposomal formulation was synthesized and evaluated for the delivery of a phosphorothioate antisense oligodeoxyribonucleotide (ODN) (G3139, oblimerson sodium, or Genasense) to Bcl-2 in K562 leukemia cells. Liposomes composed of DC-Chol/egg PC/PEG-DSPE (25:73.5:1.5, mol/mol/mol) were loaded with G3139 with high efficiency (70-80%). To prepare targeted liposomes, transferrin was first coupled to PEG-DSPE and then incorporated into the bilayer by post-insertion. The liposomes had a mean diameter of 100 to 150 nm and exhibited colloidal stability for up to 8 weeks. Uptake of Tf-conjugated G3139-containing liposomes in TfR positive K562 cells was found to be more efficient than that of the non-targeted control formulation and could be blocked by excess free Tf. Treatment with Tf-conjugated liposomes resulted in Bcl-2 protein downregulation in K562 cells that was approximately 2-fold greater than with non-targeted liposomes (p<0.05) and 10-fold greater than with free G3139. Treatment with 2 microM G3139 in Tf-conjugated liposomes resulted in >80% reduction in Bcl-2 transcript. In addition, Tf-conjugated liposomal G3139-sensitized K562 cells to daunorubicin, lowering IC50 from 1.8 microM to 0.18 microM. In conclusion, Tf-conjugated liposomes are effective delivery vehicles for G3139 antisense oligos in TfR positive K562 cells and warrant further investigation as an in vivo oligo delivery vehicle.

Molecular umbrella-assisted transport of an oligonucleotide across cholesterol-rich phospholipid bilayers

A series of molecular umbrella conjugates, derived from cholic acid, deoxycholic acid, spermidine, lysine, and 5-mercapto-2-nitrobenzoic acid, have been synthesized and found capable of transporting an attached 16-mer oligonucleotide (S-dT16) across liposomal membranes made from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidyldglycerol (POPG), and cholesterol [POPC/POPG/cholesterol (65/5/30; mol/mol/mol, v/v/v)] at 37 degrees C. Those molecular umbrellas containing four choloyl (or deoxycholoyl) groups resulted in significantly faster rates of transport as compared to those containing only two such moieties. A model that accounts for these membrane transport processes is proposed.

Delivery of different length poly(L-lysine)-conjugated ODN to HepG2 cells using N-stearyllactobionamide-modified liposomes and their enhanced cellular biological effects

Short (14-20-mer range) synthetic oligodeoxynucleotides (ODNs) allow specific modulation of cellular gene expression at various stages, thus providing a versatile tool for fundamental studies and a rational approach to anticancer chemotherapy. However, several problems, such as metabolic stability, efficient cell internalization of ODNs and their efficient entrapment into liposomes continue to markedly limit this approach. To improve the target specificity and biological activity of ODN, three different length of poly(L-lysine) (PLL) were conjugated to ODN and these conjugates were encapsulated in N-stearyllactobionamide (N-SLBA)-modified liposomes, N-SLBA is a ligand for the asialoglycoprotein receptor. Then, we investigated their effects on cell cycle and survivin protein levels of HepG2 cells. The results showed that the encapsulation efficiency was improved because the polycationic charges of PLL neutralized the polyanionic charges of ODN. Among them, PLL (M(W) 2000 and 10,000)-conjugated ODN encapsulated in N-SLBA liposomes induced apoptosis of HepG2 cells and highly inhibited survivin gene expression.

Nanocarriers: Promising Vehicle for Bioactive Drugs

Development of new delivery systems that deliver the potential drug specifically to the target site in order to meet the therapeutic needs of the patients at the required time and level remains the key challenge in the field of pharmaceutical biotechnology. Developments in this context to achieve desired goal has led to the evolution of the multidisciplinary field nanobiotechnology which involves the combination of two most promising technologies of 21st century--biotechnology and nanotechnology. Nanobiotechnology encompasses a wide array of different techniques to improve the delivery of biotech drugs, and nanoparticles offer the most suitable form whose properties can be tailored by chemical methods. This review highlights the different types of nanoparticulate delivery systems employed for biotech drugs in the field of molecular medicine with a short overlook at its applications and the probable associated drawbacks.

Antisense oligonucleotide therapy in the management of bladder cancer

PURPOSE OF REVIEW

In this paper, we will review the recent advances in antisense oligonucleotide therapy in the treatment of superficial bladder cancer. Bladder cancer has an exciting potential as a model to study antisense oligonucleotide therapy because of the ease of accessibility of treatment, ease of diagnosis through biopsy and urine cytology, and direct observation of treatment efficacy through cystoscopy and posttreatment biopsy.

RECENT FINDINGS

We will elaborate on the recent developments in the delivery of antisense oligonucleotide and the implications of these results on the use of antisense oligonucleotide intravesically. We will also discuss recent preclinical in-vitro results of antisense oligonucleotide therapy in different bladder cancer cell lines.

SUMMARY

Recent developments of the in-vitro and animal in-vivo effectiveness of antisense treatment in bladder cancer provide the foundation to pursue future phase I clinical trials. Antisense oligonucleotide technology is a promising tool that may become an effective method of treating bladder cancer.

Structural variation of cationic lipids: minimum requirement for improved oligonucleotide delivery into cells

In vivo transfection efficiency (TE) using cationic liposome/oligonucleotide (ODN) complexes is often hampered by interactions with serum components. Novel cationic lipids with different hydroxyethyl or dihydroxypropyl ammonium backbones, esterified hydrocarbon chains and hydroxy substituents have been synthesized and applied in cationic liposome formulations with and without the helper lipid DOPE (1:1, m/m). Their properties for cellular ODN delivery were determined using fluorescently labeled ODNs (F-ODNs). Cationic lipids with hydrocarbon chains esterified to non-glycerol backbones in non-vicinal configuration were completely ineffective in nuclear ODN-delivery. Instead, an increased cytoplasmic localization of F-ODNs was observed. Cationic lipids equipped with only one hydrocarbon were completely incompetent for cellular ODN delivery. In the absence of serum, all cationic lipids tested with hydrocarbon chains in vicinal configuration esterified to a glycerol backbone (the respective N-(1,2-diacyl-dihydroxypropyl)-N,N,N-trimethyl-ammoniumchlorides or N-(1,2-diacyl-dihydroxypropyl)-N(hydroxyethyl)-N,N-dimethyl-ammoniumchlorides as well as N-(1,2-diacyl-dihydroxypropyl)-N(1,2-dihydroxypropyl)-N,N-dimethyl-ammoniumchlorides with lauroyl, myristoyl, palmitoyl, stearoyl and erucoyl chains) were able to transfect cells when combined with DOPE (20-80% nuclear fluorescence). Remarkably, only the analog esterified with two myristoyl chains was equally effective even in the absence of DOPE. By adding hydroxy groups to the N-alkyl residue, TE under serum conditions was improved yielding transfection rates of 55%, 75% and 90% for 0, 1 or 2 substituted hydroxy groups, respectively. For plasmid DNA, different requirements were identified. Again, the analog with two myristoyl chains was most effective but only in the presence of DOPE. However, the addition of hydroxy groups had no influence on the TE in the presence of serum.

Polymeric microspheres as stabilizing anchors for oligonucleotide delivery to dendritic cells

The aim of this study is to evaluate a novel microspheric vector for delivery of oligonucleotides (ODN) into dendritic cells (DC). A requirement of decoy-based modulation of transcriptional activities in DC is that the ODN would have to accumulate inside the cell. Using an ex vivo DC culture model, we demonstrate that anionic microspheres (MS) coated with an ornithine/histadine-based cationic peptide (O10H6) is an effective carrier of short ODN. This method does not disrupt the colloidal nature of the microspheric particles. The MS provide stabilizing effect on DNA and O10H6 complexation. Accumulation of ODN in DC is greatly enhanced with the surface modified MS. Taken together, these data demonstrate that the self assembly system of MS(O10H6) is an effective delivery vehicle for DNA-based modulation of DC functions.

N4,N9-dioleoyl spermine is a novel nonviral lipopolyamine vector for plasmid DNA formulation

PURPOSE

To study the effect of synthesized N4,N9-dioleoyl spermine on DNA condensation and then measure its transfection efficiency in cell culture.

METHODS

The lipopolyamine was synthesized from the naturally occurring polyamine spermine. The ability of this novel compound to condense DNA was studied using ethidium bromide fluorescence quenching and light scattering assays. Transfection efficiency was studied in primary skin cells (FEK4) and in an immortalized cancer cell line (HtTA), and compared with the commercially available transfection formulations Lipofectin and Lipofectamine.

RESULTS

The synthesized N4,N9-dioleoyl spermine formula is efficient at condensing calf thymus and circular plasmid DNA and effectively transfects both primary skin cells and cancer cell lines at low charge ratios of (+/- ammonium/phosphate) 2.5.

CONCLUSIONS

N4,N9-Dioleoyl spermine condenses DNA and achieves high transfection levels in cultured cells.