Antisense delivery using protamine-oligonucleotide particles

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.

A Review of Protein- and Peptide-Based Chemical Conjugates: Past, Present, and Future

Over the past few decades, the complexity of molecular entities being advanced for therapeutic purposes has continued to evolve. A main propellent fueling innovation is the perpetual mandate within the pharmaceutical industry to meet the needs of novel disease areas and/or delivery challenges. As new mechanisms of action are uncovered, and as our understanding of existing mechanisms grows, the properties that are required and/or leveraged to enable therapeutic development continue to expand. One rapidly evolving area of interest is that of chemically enhanced peptide and protein therapeutics. While a variety of conjugate molecules such as antibody-drug conjugates, peptide/protein-PEG conjugates, and protein conjugate vaccines are already well established, others, such as antibody-oligonucleotide conjugates and peptide/protein conjugates using non-PEG polymers, are newer to clinical development. This review will evaluate the current development landscape of protein-based chemical conjugates with special attention to considerations such as modulation of pharmacokinetics, safety/tolerability, and entry into difficult to access targets, as well as bioavailability. Furthermore, for the purpose of this review, the types of molecules discussed are divided into two categories: (1) therapeutics that are enhanced by protein or peptide bioconjugation, and (2) protein and peptide therapeutics that require chemical modifications. Overall, the breadth of novel peptide- or protein-based therapeutics moving through the pipeline each year supports a path forward for the pursuit of even more complex therapeutic strategies.

Modified Stability of microRNA-Loaded Nanoparticles

microRNAs represent promising drugs to treat and prevent several diseases, such as diabetes mellitus. microRNA delivery brings many obstacles to overcome, and one strategy to bypass them is the manufacturing of self-assembled microRNA protein nanoparticles. In this work, a microRNA was combined with the cell-penetrating peptide protamine, forming so-called proticles. Previous studies demonstrated a lack of microRNA dissociation from proticles. Therefore, the goal of this study was to show the success of functionalizing binary proticles with citric acid in order to reduce the binding strength between the microRNA and protamine and further enable sufficient dissociation. Thus, we outline the importance of the present protons provided by the acid in influencing colloidal stability, achieving a constant particle size, and monodispersing the particle size distribution. The use of citric acid also provoked an increase in drug loading. Against all expectations, the AFM investigations demonstrated that our nanoparticles were loose complexes mainly consisting of water, and the addition of citric acid led to a change in shape. Moreover, a successful reduction in binding affinity and nanoparticulate stability are highlighted. Low cellular toxicity and a constant cellular uptake are demonstrated, and as uptake routes, active and passive pathways are discussed.

Cooperating minimalist nanovaccine with PD-1 blockade for effective and feasible cancer immunotherapy

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Facile antigen/adjuvant co-loaded nanovaccine made by convenient green preparation.

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The immunological activity of the antigen and adjuvant was maximally preserved.

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The minimalist nanovaccine had excellent stability and antitumor immune activation.

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Nanovaccine combined with PD-1 antibody synergistically enhanced therapy outcome.

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Good practicability for expanding clinical translation and personalized therapy.

Introduction

Tumor vaccine has been a research boom for cancer immunotherapy, while its therapeutic outcome is severely depressed by the vulnerable in vivo delivery efficiency. Moreover, tumor immune escape is also another intractable issue, which has badly whittled down the therapeutic efficiency.

Objectives

Our study aims to solve the above dilemmas by cooperating minimalist nanovaccine with PD-1 blockade for effective and feasible cancer immunotherapy.

Methods

The minimalist antigen and adjuvant co-delivery nanovaccine was developed by employing natural polycationic protamine (PRT) to carry the electronegative ovalbumin (OVA) antigen and unmethylated Cytosine-phosphorothioate-Guanine (CpG) adjuvant via convenient chemical bench-free “green” preparation without chemical-synthesis and no organic solvent was required, which could preserve the immunological activities of the antigens and adjuvants. On that basis, PD-1 antibody (aPD-1) was utilized to block the tumor immune escape and cooperate with the nanovaccine by maintaining the tumoricidal-activity of the vaccine-induced T cells.

Results

Benefited from the polycationic PRT, the facile PRT/CpG/OVA nanovaccine displayed satisfactory delivery performance, involving enhanced cellular uptake in dendritic cells (DCs), realizable endosomal escape and promoted stimulation for DCs’ maturation. These features would be helpful for the antitumor immunotherapeutic efficiency of the nanovaccine. Furthermore, the cooperation of the nanovaccine with aPD-1 synergistically improved the immunotherapy outcome, profiting by the cooperation of the “T cell induction” competency of the nanovaccine and the “T cell maintenance” function of the aPD-1.

Conclusion

This study will provide new concepts for the design and construction of facile nanovaccines, and contribute valuable scientific basis for cancer immunotherapy.

Recent Advances in the Delivery Carriers and Chemical Conjugation Strategies for Nucleic Acid Drugs

With the development of new anticancer medicines, novel modalities are being explored for cancer treatment. For many years, conventional modalities, such as small chemical drugs and antibody drugs, have worked by "inhibiting the function" of target proteins. In recent years, however, nucleic acid drugs, such as ASOs and siRNAs, have attracted attention as a new modality for cancer treatment because nucleic acid drugs can directly promote the "loss of function" of target genes. Recently, nucleic acid drugs for use in cancer therapy have been extensively developed and some of them have currently been under investigation in clinical trials. To develop novel nucleic acid drugs for cancer treatment, it is imperative that cancer researchers, including ourselves, cover and understand those latest findings. In this review, we introduce and provide an overview of various DDSs and ligand modification technologies that are being employed to improve the success and development of nucleic acid drugs, then we also discuss the future of nucleic acid drug developments for cancer therapy. It is our belief this review will increase the awareness of nucleic acid drugs worldwide and build momentum for the future development of new cancer-targeted versions of these drugs.

Emerging Applications of Nanotechnology in Healthcare Systems: Grand Challenges and Perspectives

Healthcare, as a basic human right, has often become the focus of the development of innovative technologies. Technological progress has significantly contributed to the provision of high-quality, on-time, acceptable, and affordable healthcare. Advancements in nanoscience have led to the emergence of a new generation of nanostructures. Each of them has a unique set of properties that account for their astonishing applications. Since its inception, nanotechnology has continuously affected healthcare and has exerted a tremendous influence on its transformation, contributing to better outcomes. In the last two decades, the world has seen nanotechnology taking steps towards its omnipresence and the process has been accelerated by extensive research in various healthcare sectors. The inclusion of nanotechnology and its allied nanocarriers/nanosystems in medicine is known as nanomedicine, a field that has brought about numerous benefits in disease prevention, diagnosis, and treatment. Various nanosystems have been found to be better candidates for theranostic purposes, in contrast to conventional ones. This review paper will shed light on medically significant nanosystems, as well as their applications and limitations in areas such as gene therapy, targeted drug delivery, and in the treatment of cancer and various genetic diseases. Although nanotechnology holds immense potential, it is yet to be exploited. More efforts need to be directed to overcome these limitations and make full use of its potential in order to revolutionize the healthcare sector in near future.

Use of Protamine in Nanopharmaceuticals-A Review

Macromolecular biomolecules are currently dethroning classical small molecule therapeutics because of their improved targeting and delivery properties. Protamine-a small polycationic peptide-represents a promising candidate. In nature, it binds and protects DNA against degradation during spermatogenesis due to electrostatic interactions between the negatively charged DNA-phosphate backbone and the positively charged protamine. Researchers are mimicking this technique to develop innovative nanopharmaceutical drug delivery systems, incorporating protamine as a carrier for biologically active components such as DNA or RNA. The first part of this review highlights ongoing investigations in the field of protamine-associated nanotechnology, discussing the self-assembling manufacturing process and nanoparticle engineering. Immune-modulating properties of protamine are those that lead to the second key part, which is protamine in novel vaccine technologies. Protamine-based RNA delivery systems in vaccines (some belong to the new class of mRNA-vaccines) against infectious disease and their use in cancer treatment are reviewed, and we provide an update on the current state of latest developments with protamine as pharmaceutical excipient for vaccines.

Encapsulating TGF-β1 Inhibitory Peptides P17 and P144 as a Promising Strategy to Facilitate Their Dissolution and to Improve Their Functionalization

: Transforming growth factor-beta (TGFβ1) is considered as a master regulator for many intracellular signaling pathways, including proliferation, differentiation and death, both in health and disease. It further represents an oncogenic factor in advanced tumors allowing cancer cells to be more invasive and prone to move into the metastatic process. This finding has received great attention for discovering new therapeutic molecules against the TGFβ1 pathway. Among many TGFβ1 inhibitors, peptides (P17 and P144) were designed to block the TGFβ1 pathway. However, their therapeutic applications have limited use, due to lack of selection for their targets and their possible recognition by the immune system and further due to their potential cytotoxicity on healthy cells. Besides that, P144 is a highly hydrophobic molecule with less dissolution even in organic solution. Here, we aimed to overcome the dissolution of P144, as well as design nano-delivery strategies to protect normal cells, to increase cellular penetration and to raise the targeted therapy of both P17 and P144. Peptides were encapsulated in moieties of polymer hybrid protein. Their assembly was investigated by TEM, microplate spectrum analysis and fluorescence microscopy. SMAD phosphorylation was analyzed by Western blot as a hallmark of their biological efficiency. The results showed that the encapsulation of P17 and P144 might improve their potential therapeutic applications.

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.

Immune-Mediated Inflammation in Vulnerable Atherosclerotic Plaques

Atherosclerosis is a chronic long-lasting vascular disease leading to myocardial infarction and stroke. Vulnerable atherosclerotic (AS) plaques are responsible for these life-threatening clinical endpoints. To more successfully work against atherosclerosis, improvements in early diagnosis and treatment of AS plaque lesions are required. Vulnerable AS plaques are frequently undetectable by conventional imaging because they are non-stenotic. Although blood biomarkers like lipids, C-reactive protein, interleukin-6, troponins, and natriuretic peptides are in pathological ranges, these markers are insufficient in detecting the critical perpetuation of AS anteceding endpoints. Thus, chances to treat the patient in a preventive way are wasted. It is now time to solve this dilemma because clear results indicate a benefit of anti-inflammatory therapy per se without modification of blood lipids (CANTOS Trial, NCT01327846). This fact identifies modulation of immune-mediated inflammation as a new promising point of action for the eradication of fatal atherosclerotic endpoints.

Magnetic-silk/polyethyleneimine core-shell nanoparticles for targeted gene delivery into human breast cancer cells

The lack of efficient and cost-effective methods for gene delivery has significantly hindered the applications of gene therapy. In this paper, a simple one step and cost effective salting-out method has been explored to fabricate silk-PEI nanoparticles (SPPs) and magnetic-silk/PEI core-shell nanoparticles (MSPPs) for targeted delivery of c-myc antisense oligodeoxynucleotides (ODNs) into MDA-MB-231 breast cancer cells. The size and zeta potential of the particles were controlled by adjusting the amount of silk fibroin in particle synthesis. Lower surface charges and reduced cytotoxicity were achieved for MSPPs compared with PEI coated magnetic nanoparticles (MPPs). Both SPPs and MSPPs were capable of delivering the ODNs into MDA-MB-231 cells and significantly inhibited the cell growth. Through magnetofection, high ODN uptake efficiencies (over 70%) were achieved within 20 min using MSPPs as carriers, exhibiting a significantly enhanced uptake effect compared to the same carriers via non-magnetofection. Both SPPs and MSPPs exhibited a significantly higher inhibition effect against MDA-MB-231 breast cancer cells compared to human dermal fibroblast (HDF) cells. Targeted ODN delivery was achieved using MSPPs with the help of a magnet, making them promising candidates for targeted gene therapy applications.

Complex formation with protamine prolongs the thrombin-inhibiting effect of DNA aptamer in vivo

Antithrombin DNA aptamersRE31 are single-chain oligonucleotides that fold into three-dimensional forms allowing them to bind the enzyme with high affinity and inhibit its activity in vivo. They are rapidly degraded by a nonspecific nuclease, and, to prolong the lifetime of the aptamer DNA in the bloodstream, it is necessary to coat it with a polymer envelope. A new approach to solving this problem based on preparation of DNA-polyelectrolyte complexes with a minimal particle size that can circulate with blood flow. In our experiments, the negatively charged aptamer DNA RE31 was coated step-by-step with positively charged protamine. They had protamine/aptamer ratios of 0.2/1 and 0.4/1 by charge, with particle size being determined by dynamic light scattering. The aptamer DNA-protamine complexes were administered to rats, followed by ex vivo analysis of blood samples. The results showed that prothrombin time (PT) increased by a factor of 5.6-6.7 within 2 h after injection and remained at approximately the same level for 6 h, while injections of pure protamine did not lead to any noticeable change in clotting time. Thus, complexation with protamine proved to prolong the inhibitory activity of the RE31 DNA aptamer.

Manufacturing of a Secretoneurin Drug Delivery System with Self-Assembled Protamine Nanoparticles by Titration

Since therapeutic peptides and oligonucleotides are gathering interests as active pharmaceutical ingredients (APIs), nanoparticulate drug delivery systems are becoming of great importance. Thereby, the possibility to design drug delivery systems according to the therapeutic needs of APIs enhances clinical implementation. Over the last years, the focus of our group was laid on protamine-oligonucleotide-nanoparticles (so called proticles), however, the possibility to modify the size, zeta potential or loading efficiencies was limited. Therefore, at the present study we integrated a stepwise addition of protamine (titration) into the formation process of proticles loaded with the angiogenic neuropeptide secretoneurin (SN). A particle size around 130 nm was determined when proticles were assembled by the commonly used protamine addition at once. Through application of the protamine titration process it was possible to modify and adjust the particle size between approx. 120 and 1200 nm (dependent on mass ratio) without influencing the SN loading capacity. Dynamic light scattering pointed out that the difference in particle size was most probably the result of a secondary aggregation. Initially-formed particles of early stages in the titration process aggregated towards bigger assemblies. Atomic-force-microscopy images also revealed differences in morphology along with different particle size. In contrast, the SN loading was only influenced by the applied mass ratio, where a slight saturation effect was observable. Up to 65% of deployed SN could be imbedded into the proticle matrix. An in-vivo biodistribution study (i.m.) showed a retarded distribution of SN from the site of injection after the application of a SN-proticle formulation. Further, it was demonstrated that SN loaded proticles can be successfully freeze-dried and resuspended afterwards. To conclude, the integration of the protamine titration process offers new possibilities for the formulation of proticles in order to address key parameters of drug delivery systems as size, API loading or modified drug release.

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.

Recent Advances in Targeted, Self-Assembling Nanoparticles to Address Vascular Damage Due to Atherosclerosis

Self-assembling nanoparticles functionalized with targeting moieties have significant potential for atherosclerosis nanomedicine. While self-assembly allows the easy construction (and degradation) of nanoparticles with therapeutic or diagnostic functionality, or both, the targeting agent can direct them to a specific molecular marker within a given stage of the disease. Therefore, supramolecular nanoparticles have been investigated in the last decade as molecular imaging agents or explored as nanocarriers that can decrease the systemic toxicity of drugs by producing accumulation predominantly in specific tissues of interest. In this Progress Report, the pathogenesis of atherosclerosis and the damage caused to vascular tissue are described, as well as the current diagnostic and treatment options. An overview of targeted strategies using self-assembling nanoparticles is provided, including liposomes, high density lipoproteins, protein cages, micelles, proticles, and perfluorocarbon nanoparticles. Finally, an overview is given of current challenges, limitations, and future applications for personalized medicine in the context of atherosclerosis of self-assembling nanoparticles.

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.

Interleukin 10-coated nanoparticle systems compared for molecular imaging of atherosclerotic lesions

Atherosclerosis (AS) is one of the leading causes of mortality in high-income countries. Early diagnosis of vulnerable atherosclerotic lesions is one of the biggest challenges currently facing cardiovascular medicine. The present study focuses on developing targeted nanoparticles (NPs) in order to improve the detection of vulnerable atherosclerotic-plaques. Various biomarkers involved in the pathogenesis of atherosclerotic-plaques have been identified and one of these promising candidates for diagnostic targeting is interleukin 10 (IL10). IL10 has been shown to be a key anti-inflammatory responding cytokine in the early stages of atherogenesis, and has already been used for therapeutic interventions in humans and mice. IL10, the targeting sequence, was coupled to two different types of NPs: protamine-oligonucleotide NPs (proticles) and sterically stabilized liposomes in order to address the question of whether the recognition and detection of atherosclerotic-lesions is primarily determined by the targeting sequence itself, or whether it depends on the NP carrier system to which the biomarker is coupled. Each IL10-targeted NP was assessed based on its sensitivity and selectivity toward characterizing atherosclerotic-plaque lesions using an apolipoprotein E-deficient mouse as the model of atherosclerosis. Aortas from apolipoprotein E-deficient mice fed a high fat diet, were stained with either fluorescence-labeled IL10 or IL10-coupled NPs. Ex vivo imaging was performed using confocal laser-scanning microscopy. We found that IL10-targeted proticles generated a stronger signal by accumulating at the surface of atherosclerotic-plaques, while IL10-targeted, sterically stabilized liposomes showed a staining pattern deeper in the plaque compared to the fluorescence-labeled IL10 alone. Our results point to a promising route for enhanced in vivo imaging using IL10-targeted NPs. NPs allow a higher payload of signal emitting molecules to be delivered to the atherosclerotic-plaques, thus improving signal detection. Importantly, this allows for the opportunity to visualize different areas within the plaque scenario, depending on the nature of the applied nanocarrier.

Oncomodulin/truncated protamine-mediated Nogo-66 receptor small interference RNA delivery promotes axon regeneration in retinal ganglion cells

The optic nerve often suffers regenerative failure after injury, leading to serious visual impairment such as glaucoma. The main inhibitory factors, including Nogo-A, oligodendrocyte myelin glycoprotein, and myelin-associated glycoprotein, exert their inhibitory effects on axonal growth through the same receptor, the Nogo-66 receptor (NgR). Oncomodulin (OM), a calcium-binding protein with a molecular weight of an ∼12 kDa, which is secreted from activated macrophages, has been demonstrated to have high and specific affinity for retinal ganglion cells (RGC) and promote greater axonal regeneration than other known polypeptide growth factors. Protamine has been reported to effectively deliver small interference RNA (siRNA) into cells. Accordingly, a fusion protein of OM and truncated protamine (tp) may be used as a vehicle for the delivery of NgR siRNA into RGC for gene therapy. To test this hypothesis, we constructed OM and tp fusion protein (OM/tp) expression vectors. Using the indirect immunofluorescence labeling method, OM/tp fusion proteins were found to have a high affinity for RGC. The gel shift assay showed that the OM/tp fusion proteins retained the capacity to bind to DNA. Using OM/tp fusion proteins as a delivery tool, the siRNA of NgR was effectively transfected into cells and significantly down-regulated NgR expression levels. More importantly, OM/tp-NgR siRNA dramatically promoted axonal growth of RGC compared with the application of OM/tp recombinant protein or NgR siRNA alone in vitro. In addition, OM/tp-NgR siRNA highly elevated intracellular cyclic adenosine monophosphate (cAMP) levels and inhibited activation of the Ras homolog gene family, member A (RhoA). Taken together, our data demonstrated that the recombinant OM/tp fusion proteins retained the functions of both OM and tp, and that OM/tp-NgR siRNA might potentially be used for the treatment of optic nerve injury.

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

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

Characterization of protamine uptake by opossum kidney epithelial cells

Protamine, a mixture of polypeptides that is rich in arginine, has been used clinically as an antidote to heparin overdoses and a complexing agent in a long-acting insulin preparation. When protamine is administered intravenously, its abundant accumulation in the kidneys has been reported. However, the renal uptake mechanism for protamine is not clear. In this study, we examined the transport mechanism for protamine in opossum kidney (OK) cells, a suitable in vitro model for renal proximal tubular epithelial cells. Flow cytometric analysis revealed that the association of fluorescein isothiocyanate (FITC)-labeled protamine from salmon (FITC-protamine) by OK cells was inhibited by unlabeled protamine in a concentration-dependent manner. The association of FITC-protamine was temperature- and energy-dependent. Confocal microscopy analysis showed that the fluorescence was localized in the cytoplasm and nucleus of OK cells. In addition, FITC-protamine association was inhibited by cationic drugs such as polycationic gentamicin and polymixin B, but it was increased by a basic amino acid, arginine. Inhibitors for clathrin- and caveolin-dependent endocytosis showed inhibitory effects on FITC-protamine association. Pretreatment with heparinase III partially but significantly decreased the association of FITC-protamine. These results suggest that protamine may be taken up by OK cells via receptor-mediated endocytosis, which may result in its localization in the cytoplasm and nucleus of the cells.

Mannosylated chitosan nanoparticles for delivery of antisense oligonucleotides for macrophage targeting

The therapeutic potential of antisense oligonucleotides (ASODN) is primarily dependent upon its safe and efficient delivery to specific cells overcoming degradation and maximizing cellular uptake in vivo. The present study focuses on designing mannosylated low molecular weight (LMW) chitosan nanoconstructs for safe ODNs delivery by macrophage targeting. Mannose groups were coupled with LMW chitosan and characterized spectroscopically. Mannosylated chitosan ODN nanoparticles (MCHODN NPs) were formulated by self-assembled method using various N/P ratio (moles of amine groups of MCH to phosphate moieties of ODNs) and characterized for gel retardation assay, physicochemical characteristics, cytotoxicity and transfection efficiency, and antisense assay. Complete complexation of MCH/ODN was achieved at charge ratio of 1:1 and above. On increasing the N/P ratio of MCH/ODN, particle size of the NPs decreased whereas zeta potential (ZV) increased. MCHODN NPs displayed much higher transfection efficiency into Raw 264.7 cells (bears mannose receptors) than Hela cells and no significant toxicity was observed at all MCH concentrations. Antisense assay revealed that reduction in lipopolysaccharide (LPS) induced serum TNF-α is due to antisense activity of TJU-2755 ODN (sequence complementary to 3′-UTR of TNF-α). These results suggest that MCHODN NPs are acceptable choice to improve transfection efficiency in vitro and in vivo.

A novel therapeutic drug for colon cancer: EpCAM scFv-truncated protamine (tp)-siRNA

Colon cancer is a type of malignant tumor that causes considerable mortality worldwide. Epithelial cellular adhesion molecule (EpCAM), a tumor-associated antigen of colon tumors, is a target for colon cancer therapy. EpCAM-specific monoclonal antibodies (mAbs) have been applied in human colon cancer since the 1990s; however, the therapeutic effects are limited. EpCAM activates nuclear signaling pathways by releasing its intracellular domain (EpICD). The released EpICD stimulates the Wnt/β-catenin signaling pathway, which is also strongly associated with tumorigenesis. EpCAM is also a target gene of the Wnt/β-catenin signaling pathway. EpCAM and the Wnt/β-catenin signaling pathway form a functional interaction cycle in colon cancer. Thus, we propose a new therapeutic drug for colon cancer: an EpCAM single-chain fragment variable antibody (scFv)-truncated protamine-siRNA. EpCAM scFv can recognize and bind colon cancer cells through its EpCAM antigen activity. Furthermore, the specific siRNA transferred into colon cancer cells specifically inhibits Wnt/β-catenin signal transmission. Therefore, this new drug may efficiently interrupt the functional cycle between EpCAM and Wnt/β-catenin signaling and be an effective therapeutic strategy for colon cancer.

In vivo delivery of cell-permeable antisense hypoxia-inducible factor 1α oligonucleotide to adipose tissue reduces adiposity in obese mice

Ongoing research has gradually recognized and understood the importance of adipose tissue (AT) angiogenesis as a key modulating factor of adipogenesis in the development of obesity. Previously, we carried out the first in vitro demonstration of the down-regulation of hypoxic angiogenesis during adipogenesis using cell-permeable chemical conjugates composed of antisense hypoxia-inducible factor 1α (HIF1α) oligonucleotide (ASO) and low-molecular weight protamine (LMWP). To further confirm the in vivo feasibility, we administered ASO-LMWP conjugates (AL) to diet-induced obese (DIO) mice by intraperitoneal injection (IP). Results showed that the AL conjugates significantly reduced the body weight, total fat tissue weight, and plasma lipid concentrations in the mice. Moreover, the AL conjugates not only decreased liver weight and hepatic triglyceride concentration but also significantly attenuated subcutaneous adipocyte cell size, which was conversely increased in the AL-untreated high-fat diet (HFD) group. Interestingly, more blood vessels were observed in the HFD group than in the lean group, indicating that blood vessel development could induce growth of the fat mass. This pattern was reversed in the AL-treated groups, which displayed a decrease in blood vessel density compared to the AL-untreated HFD group. This study presents the first in vivo evidence, in an obese mouse model, of the feasibility of achieving a biological treatment modality for obesity by blocking the angiogenic transcriptional factor HIF1α, thereby limiting angiogenesis, via the use of an adipose tissue-permeable ASO-LMWP.

New tumor-targeted nanosized delivery carrier for oligonucleotides: characteristics in vitro and in vivo

Background

The purpose of this study was to investigate the in vitro and in vivo characteristics of a new tumor-targeted nanosized delivery carrier for antisense oligonucleotide (ASON).

Methods

Polyethylenimine (PEI) was used to condense ASON to form nanosized complexes (PEI/ASON), which were then modified using asparagine-glycine-arginine (NGR) peptide to obtain a tumor-targeted nanosized delivery carrier (NGR/PEI/ASON). The conditions required to form PEI/ASON were investigated.

Results

A linear correlation between the natural logarithm of the N/P ratio (PEI to ASON) and the zeta potential of the PEI/ASON complexes was found, ranging from 1.5 to 5.0. The pH of the solution strongly influenced the zeta potential of the PEI/ASON complexes. PEI/ASON and NGR/PEI/ASON were stable in RPMI-1640 culture medium in the presence of Dextran 70. Incorporation of ASON into PEI/ASON and NGR/PEI/ASON complexes prevented degradation of ASON by DNase I.

Conclusion

Both ASON/PEI and NGR/PEI/ASON complexes enhanced the uptake of ASON by EC9706 cells in vitro. In vivo, NGR/PEI/ASON complexes had the ability to target tumor tissues effectively.

Adiponectin-coated nanoparticles for enhanced imaging of atherosclerotic plaques

BACKGROUND

Atherosclerosis is a leading cause of mortality in the Western world, and plaque diagnosis is still a challenge in cardiovascular medicine. The main focus of this study was to make atherosclerotic plaques visible using targeted nanoparticles for improved imaging. Today various biomarkers are known to be involved in the pathophysiologic scenario of atherosclerotic plaques. One promising new candidate is the globular domain of the adipocytokine adiponectin (gAd), which was used as a targeting sequence in this study.

METHODS

gAd was coupled to two different types of nanoparticles, namely protamine-oligonucleotide nanoparticles, known as proticles, and sterically stabilized liposomes. Both gAd-targeted nanoparticles were investigated for their potency to characterize critical scenarios within early and advanced atherosclerotic plaque lesions using an atherosclerotic mouse model. Aortic tissue from wild type and apolipoprotein E-deficient mice, both fed a high-fat diet, were stained with either fluorescent-labeled gAd or gAd-coupled nanoparticles. Ex vivo imaging was performed using confocal laser scanning microscopy.

RESULTS

gAd-targeted sterically stabilized liposomes generated a strong signal by accumulating at the surface of atherosclerotic plaques, while gAd-targeted proticles became internalized and showed more spotted plaque staining.

CONCLUSION

Our results offer a promising perspective for enhanced in vivo imaging using gAd-targeted nanoparticles. By means of nanoparticles, a higher payload of signal emitting molecules could be transported to atherosclerotic plaques. Additionally, the opportunity is opened up to visualize different regions in the plaque scenario, depending on the nature of the nanoparticle used.

A covalently stabilized lipid-polycation-DNA (sLPD) vector for antisense oligonucleotide delivery

Antisense oligonucleotide G3139 is designed for Bcl-2 downregulation and is known to induce toll-like receptor activation. Novel stabilized lipid-polycation-DNA (sLPD) nanoparticles were constructed and evaluated for the delivery of G3139 to human carcinoma KB cells and for bioactivity in vivo. Polyethylenimine (PEI) was incorporated as a DNA condensing agent. The lipid composition used was DOTAP/DDAB/Chol/TPGS/linoleic acid/hexadecenal at molar ratios of 30/30/34/1/5/0.2. The nanoparticles were stabilized by the formation of a reversible covalent bond between the aldehyde group on the cis-11-hexadecenal and amines on the PEI. When sLPDs were used to transfect KB cells, 90.4% Bcl-2 downregulation was observed, compared to no significant downregulation by free G3139 and 54.6% downregulation by nonstabilized LPD-G3139. The sLPDs were then evaluated for therapeutic efficacy in mice bearing KB subcutaneous tumors and were found to trigger a strong antitumor response, inhibiting tumor growth and prolonging survival with 72% increase in lifespan (ILS). Consistent with previous reports on other G3139 nanoparticles, the increased antitumor activities of sLPDs in vivo were found to be associated with increased cytokine induction rather than Bcl-2 downregulation, suggesting an immunological mechanism.

DNA-based applications in nanobiotechnology

Biological molecules such as deoxyribonucleic acid (DNA) have shown great potential in fabrication and construction of nanostructures and devices. The very properties that make DNA so effective as genetic material also make it a very suitable molecule for programmed self-assembly. The use of DNA to assemble metals or semiconducting particles has been extended to construct metallic nanowires and functionalized nanotubes. This paper highlights some important aspects of conjugating the unique physical properties of dots or wires with the remarkable recognition capabilities of DNA which could lead to miniaturizing biological electronics and optical devices, including biosensors and probes. Attempts to use DNA-based nanocarriers for gene delivery are discussed. In addition, the ecological advantages and risks of nanotechnology including DNA-based nanobiotechnology are evaluated.

Generation and characterization of a fusion protein of single-chain fragment variable antibody against hemagglutinin antigen of avian influenza virus and truncated protamine

The hemagglutinin antigen (HA) of avian influenza virus (AIV) is an immunogen abundant on the surfaces of infected cells, and can be used as a target for specific antibodies to clear viral infection. Protamine has been demonstrated to deliver DNA into cells effectively. Accordingly, a fusion protein of anti-HA single-chain fragment variable (scFv) and truncated protamine (tP) may be used as a vehicle for delivering the anti-AIV siRNA into the AIV-infected cells for gene therapy. To test this hypothesis, we constructed a novel recombinant plasmid, pET28-scFv-tP, by connecting the genes for anti-H5N1 AIV HA-specific scFv with synthesized oligonucleotides encoding the 22 amino acids of human tP and a linker. Furthermore, the recombinant scFV-tP was expressed and purified, with a yield of 7-8mg of scFv-tP and a purity of >92% from 1L of bacterial culture. Characterization of its bioactivity revealed that scFv-tP recognized HA, similar to its scFv control, in a dose-dependent manner and that the scFv-tP, but not its scFv control, bound to DNA and delivered plasmid and oligonucleotide DNA into the AIV-infected MDCK cells effectively. More importantly, transfection with the mixture of the scFv-tP and plasmid for the NP-specific siRNA significantly inhibited the replication of AIV in MDCK cells, as compared with that transfection with the scFv-plasmid mixture, even with the plasmid in liposome. Our data demonstrated that the recombinant scFv-tP retained the functions of both scFv and tP, and might be potentially used for delivering genetic materials for targeting therapy of AIV infection in vivo.

Novel siRNA delivery system to target podocytes in vivo

Podocytes are injured in several glomerular diseases. To alter gene expression specifically in podocytes in vivo, we took advantage of their active endocytotic machinery and developed a method for the targeted delivery of small interfering ribonucleic acids (siRNA). We generated an anti-mouse podocyte antibody that binds to rat and mouse podocytes in vivo. The polyclonal IgG antibody was cleaved into monovalent fragments, while preserving the antigen recognition sites. One Neutravidin molecule was linked to each monovalent IgG via the available sulfohydryl group. Protamine, a polycationic nuclear protein and universal adaptor for anionic siRNA, was linked to the neutravidin via biotin. The delivery system was named shamporter (sheep anti mouse podocyte transporter). Injection of shamporter coupled with either nephrin siRNA or TRPC6 siRNA via tail vein into normal rats substantially reduced the protein levels of nephrin or TRPC6 respectively, measured by western blot analysis and immunostaining. The effect was target specific because other podocyte-specific genes remained unchanged. Shamporter + nephrin siRNA induced transient proteinuria in rats. Control rats injected with shamporter coupled to control-siRNA showed no changes. These results show for the first time that siRNA can be delivered efficiently and specifically to podocytes in vivo using an antibody-delivery system.

Specific down regulation of 3T3-L1 adipocyte differentiation by cell-permeable antisense HIF1alpha-oligonucleotide

Hypoxia is a strong modulator of angiogenesis, accelerating adipose tissue expansion, suggesting that hypoxia inducible factor 1alpha (HIF1alpha) can be a novel target for anti-obesity. We conjugated antisense-HIF1alpha-oligonucleotide (ASO) with low molecular weight protamine (LMWP), a cell-penetrating peptide, to enhance its ability to block hypoxic-angiogenesis, thereby eliciting an anti-obesity effect. Nano-sized ASO-LMWP (AS-L) conjugates enhanced cellular uptake of ASO without yielding a cytotoxic effect and protected the ASO against enzymatic attack and chemical reduction. AS-L showed enhanced intra-cellular localization compared to naked ASO and the complex of ASO with lipofectamine during hypoxic-differentiation. Consequently AS-L induced significant down-regulation of leptin and VEGF gene expressions, thereby reducing fat accumulation in the cell. This proof-of-concept study shows that AS-L produces an inhibitory effect on adipogenesis and angiogenesis during differentiation, indicating LMWP mediated ASO delivery can potentially be a safe and promising treatment for obesity.

Nanoparticle-mediated gene delivery

Nonviral gene delivery has been gaining considerable attention recently. Although the efficacy of DNA transfection, which is a major concern, is low in nonviral vector-mediated gene transfer compared with viral ones, nonviral vectors are relatively easy to prepare, less immunogenic and oncogenic, and have no potential of virus recombination and no limitation on the size of a transferred gene. The ability to incorporate genetic materials such as plasmid DNA, RNA, and siRNA into functionalized nanoparticles with little toxicity demonstrates a new era in pharmacotherapy for delivering genes selectively to tissues and cells. In this chapter, we highlight the basic concepts and applications of nonviral gene delivery using super paramagnetic iron oxide nanoparticles and functionalized silica nanoparticles. The experimental protocols related to these topics are described in the chapter.

Delivery of antisense oligodeoxyribonucleotide lipopolyplex nanoparticles assembled by microfluidic hydrodynamic focusing

A multi-inlet microfluidic hydrodynamic focusing (MF) system to prepare lipopolyplex (LP) containing Bcl-2 antisense deoxyoligonucleotide (ODN) was developed and evaluated. The lipopolyplex nanoparticles consist of ODN:protamine:lipids (1:0.3:12.5wt/wt ratio) and the lipids included DC-Chol:egg PC:PEG-DSPE (40:58:2mol/mol%). Using K562 human erythroleukemia cells, which contain an abundance of Bcl-2 and overexpression of transferrin receptors (TfR), and G3139 (oblimerson sodium or Genasense(TM)) as a model cell line and drug, respectively, the Bcl-2 down-regulation at the mRNA and protein levels as well as cellular uptake and apoptosis was compared between the conventional bulk mixing (BM) method and the MF method. The lipopolyplex size and surface charge were characterized by dynamic light scattering (DLS) and zeta potential (zeta) measurement, respectively, while the ODN encapsulation efficiency was determined by gel electrophoresis. Cryogenic transmission electron microscopy (Cryo-TEM) was used to determine the morphology of LPs. Our results demonstrated that MF produced LP nanoparticles had similar structures but smaller size and size distribution compared to BM LP nanoparticles. MF LP nanoparticles had higher level of Bcl-2 antisense uptake and showed more efficient down-regulation of Bcl-2 protein level than BM LP nanoparticles.

Nanotechnologies and controlled release systems for the delivery of antisense oligonucleotides and small interfering RNA

Antisense oligonucleotides and small interfering RNA have enormous potential for the treatment of a number of diseases, including cancer. However, several impediments to their widespread use as drugs still have to be overcome: in particular their lack of stability in physiological fluids and their poor penetration into cells. Association with or encapsulation within nano- and microsized drug delivery systems could help to solve these problems. In this review, we describe the progress that has been made using delivery systems composed of natural or synthetic polymers in the form of complexes, nanoparticles or microparticles.