Absence of unspecific innate immune cell activation by GATA-3-specific DNAzymes

Regulation of Eosinophilia in Asthma-New Therapeutic Approaches for Asthma Treatment

Asthma is a complex and chronic inflammatory disease of the airways, characterized by variable and recurring symptoms, reversible airflow obstruction, bronchospasm, and airway eosinophilia. As the pathophysiology of asthma is becoming clearer, the identification of new valuable drug targets is emerging. IL-5 is one of these such targets because it is the major cytokine supporting eosinophilia and is responsible for terminal differentiation of human eosinophils, regulating eosinophil proliferation, differentiation, maturation, migration, and prevention of cellular apoptosis. Blockade of the IL-5 pathway has been shown to be efficacious for the treatment of eosinophilic asthma. However, several other inflammatory pathways have been shown to support eosinophilia, including IL-13, the alarmin cytokines TSLP and IL-33, and the IL-3/5/GM-CSF axis. These and other alternate pathways leading to airway eosinophilia will be described, and the efficacy of therapeutics that have been developed to block these pathways will be evaluated.

GATA-3 as a Potential Therapeutic Target for Insulin Resistance and Type 2 Diabetes Mellitus

Impaired adipogenesis plays an important role in the development of obesity-associated insulin resistance and type 2 diabetes as it leads to ectopic fat deposition. The anti-adipogenic transcription factor GATA-3 was identified as one of the potential molecular targets responsible for the impairment of adipogenesis. The expression of GATA-3 is higher in insulinresistant obese individuals compared to BMI-matched insulin-sensitive counterparts. Adipose tissue inflammation is a crucial mediator of this process. Hyperglycemia mediates the activation of the immune system, partially through upregulation of GATA- 3, causing exacerbation of the inflammatory state associated with obesity. This review discusses the evidence supporting the inhibition of GATA-3 as a useful therapeutic strategy in obesity-associated insulin resistance and type 2 diabetes, through up-regulation adipogenesis and amelioration of the immune response.

Development of orally administered insulin-loaded polymeric-oligonucleotide nanoparticles: statistical optimization and physicochemical characterization

INTRODUCTION

Therapeutic peptides are administered via parenteral route due to poor absorption in the gastrointestinal (GI) tract, instability in gastric acid, and GI enzymes. Polymeric drug delivery systems have achieved significant interest in pharmaceutical research due to its feasibility in protecting proteins, tissue targeting, and controlled drug release pattern.

MATERIALS AND METHODS

In this study, the size, polydispersity index, and zeta potential of insulin-loaded nanoparticles were characterized by dynamic light scattering and laser Doppler micro-electrophoresis. The main and interaction effects of chitosan concentration and Dz13Scr concentration on the physicochemical properties of the prepared insulin-loaded nanoparticles (size, polydispersity index, and zeta potential) were evaluated statistically using analysis of variance. A robust procedure of reversed-phase high-performance liquid chromatography was developed to quantify insulin release in simulated GI buffer. Results and discussion: We reported on the effect of two independent parameters, including polymer concentration and oligonucleotide concentration, on the physical characteristics of particles. Chitosan concentration was significant in predicting the size of insulin-loaded CS-Dz13Scr particles. In terms of zeta potential, both chitosan concentration and squared term of chitosan were significant factors that affect the surface charge of particles, which was attributed to the availability of positively-charged amino groups during interaction with negatively-charged Dz13Scr. The excipients used in this study could fabricate nanoparticles with negligible toxicity in GI cells and skeletal muscle cells. The developed formulation could conserve the physicochemical properties after being stored for 1 month at 4 °C.

CONCLUSION

The obtained results revealed satisfactory results for insulin-loaded CS-Dz13Scr nanoparticles (159.3 nm, pdi 0.331, -1.08 mV). No such similar study has been reported to date to identify the main and interactive significance of the above parameters for the characterization of insulin-loaded polymeric-oligonucleotide nanoparticles. This research is of importance for the understanding and development of protein-loaded nanoparticles for oral delivery.

Development and characterization of DNAzyme candidates demonstrating significant efficiency against human rhinoviruses

BACKGROUND

Infections with human rhinoviruses (RVs) are responsible for millions of common cold episodes and the majority of asthma exacerbations, especially in childhood. No drugs specifically targeting RVs are available.

OBJECTIVE

We sought to identify specific anti-RV molecules based on DNAzyme technology as candidates to a clinical study.

METHODS

A total of 226 candidate DNAzymes were designed against 2 regions of RV RNA genome identified to be sufficiently highly conserved between virus strains (ie, the 5'-untranslated region and cis-acting replication element) by using 3 test strains: RVA1, RVA16, and RVA29. All DNAzymes were screened for their cleavage efficiency against in vitro-expressed viral RNA. Those showing any catalytic activity were subjected to bioinformatic analysis of their reverse complementarity to 322 published RV genomic sequences. Further molecular optimization was conducted for the most promising candidates. Cytotoxic and off-target effects were excluded in HEK293 cell-based systems. Antiviral efficiency was analyzed in infected human bronchial BEAS-2B cells and ex vivo-cultured human sinonasal tissue.

RESULTS

Screening phase-generated DNAzymes characterized by either good catalytic activity or by high RV strain coverage but no single molecule represented a satisfactory combination of those 2 features. Modifications in length of the binding domains of 2 lead candidates, Dua-01(-L12R9) and Dua-02(-L10R11), improved their cleavage efficiency to an excellent level, with no loss in eminent strain coverage (about 98%). Both DNAzymes showed highly favorable cytotoxic/off-target profiles. Subsequent testing of Dua-01-L12R9 in BEAS-2B cells and sinonasal tissue demonstrated its significant antiviral efficiency.

CONCLUSIONS

Effective and specific management of RV infections with Dua-01-L12R9 might be useful in preventing asthma exacerbations, which should be verified by clinical trials.

GATA-3-specific DNAzyme - A novel approach for stratified asthma therapy

It is now well established that type-2 immune mechanisms drive the inflammation in about 50% of asthma patients. The major cellular and molecular players regulating this important network have been identified. In terms of therapeutic intervention, cytokine and cytokine-receptor pathways have been given major attention, since these molecules are relatively easily accessible for a blockade through monoclonal antibodies, and a number of positive clinical results support this concept. However, targeting events controlling the type-2 immunity network upstream of selective cytokine pathways would be equally attractive. Type-2 immunity is regulated through a delicate interplay of several transcription factors (including GATA-3, STAT-6, NFAT, IRF4, c-maf), with GATA-3 as master regulator in this regard. Since transcription factors are intracellularly located they cannot be directly targeted by monoclonal antibodies. For intracellular targets, antisense technologies such as antisense DNA and siRNA have been shown to be a promising approach, and have recently made major advances toward clinical application. Here, we summarize the development of a GATA-3-specific DNAzyme-a molecule class that combines the superior specificity of antisense molecules with an inherent RNA-cleaving enzymatic activity-for the treatment of type-2-driven asthma from preclinical development toward a proof-of-concept clinical study.

Broad Th2 neutralization and anti-inflammatory action of pentosan polysulfate sodium in experimental allergic rhinitis

Background

Th2 cytokines like interleukin‐4, ‐5, and ‐13 are regarded as important drivers of the immunopathology underlying allergic rhinitis (AR) and asthma. The present study explores the capacity of pentosan polysulfate sodium (PPS), a semi‐synthetic heparin‐like macromolecular carbohydrate, to bind Th2 cytokines and exert biological neutralization in vitro, as well as anti‐inflammatory actions in vivo.

Methodology

The capacity of PPS to bind recombinant Th2 cytokines was tested with surface plasmon resonance (SPR) technology and biological Th2 neutralization was assessed by Th2‐dependent proliferation assays. The in vivo anti‐inflammatory action of PPS was studied using a validated Guinea‐pig model of AR.

Results

Binding studies revealed a strong and specific binding of PPS to IL‐4, IL‐5, and IL‐13 with IC values suggesting as stronger cytokine binding than for heparin. Cytokine binding translated to a biological neutralization as PPS dose dependently inhibited Th2‐dependent cell proliferation. Topical administration of PPS 30 min prior to nasal allergen challenge of sensitized animals significantly reduced late phase plasma extravasation, luminal influx of eosinophils, neutrophils, and total lavage leukocytes. Similar, albeit not statistically secured, effects were found for tissue leukocytes and mucus hyper‐secretion. The anti‐inflammatory effects of PPS compared favorably with established topical nasal steroid treatment.

Conclusion

This study points out PPS as a potent Th2 cytokine‐binding molecule with biological neutralization capacity and broad anti‐inflammatory effects in vivo. As such PPS fulfills the role as a potential candidate molecule for the treatment of AR and further studies of clinical efficacy seems highly warranted.

New concepts in asthma: clinical phenotypes and pathophysiological mechanisms

Asthma is among the most common chronic inflammatory diseases worldwide. Recent evidence indicates that the pathogenesis shows a high degree of heterogeneity. Patient subsets have been identified that exhibit different cellular and molecular patterns of dysregulation. A prominent example is eosinophilic Th2-driven asthma. These unique and molecular patterns are termed endotypes. Characterization of endotypes has broad implications for therapeutic interventions. Although ∼80% of asthmatic patients respond well to standard anti-inflammatory therapies, the remaining subset particularly consisting of severe patients requires a more specialized endotype-specific approach. This interrelationship between clinical phenotypes, molecular endotypes and endotype-specific therapies is the focus of this review.

Allergen-induced asthmatic responses modified by a GATA3-specific DNAzyme

BACKGROUND

The most prevalent phenotype of asthma is characterized by eosinophil-dominated inflammation that is driven by a type 2 helper T cell (Th2). Therapeutic targeting of GATA3, an important transcription factor of the Th2 pathway, may be beneficial. We evaluated the safety and efficacy of SB010, a novel DNA enzyme (DNAzyme) that is able to cleave and inactivate GATA3 messenger RNA (mRNA).

METHODS

We conducted a randomized, double-blind, placebo-controlled, multicenter clinical trial of SB010 involving patients who had allergic asthma with sputum eosinophilia and who also had biphasic early and late asthmatic responses after laboratory-based allergen provocation. A total of 40 patients could be evaluated; 21 were assigned to receive 10 mg of SB010, and 19 were assigned to receive placebo, with each study drug administered by means of inhalation once daily for 28 days. An allergen challenge was performed before and after the 28-day period. The primary end point was the late asthmatic response as quantified by the change in the area under the curve (AUC) for forced expiratory volume in 1 second (FEV1).

RESULTS

After 28 days, SB010 attenuated the mean late asthmatic response by 34%, as compared with the baseline response, according to the AUC for FEV1, whereas placebo was associated with a 1% increase in the AUC for FEV1 (P=0.02). The early asthmatic response with SB010 was attenuated by 11% as measured by the AUC for FEV1, whereas the early response with placebo was increased by 10% (P=0.03). Inhibition of the late asthmatic response by SB010 was associated with attenuation of allergen-induced sputum eosinophilia and with lower levels of tryptase in sputum and lower plasma levels of interleukin-5. Allergen-induced levels of fractional exhaled nitric oxide and airway hyperresponsiveness to methacholine were not affected by either SB010 or placebo.

CONCLUSIONS

Treatment with SB010 significantly attenuated both late and early asthmatic responses after allergen provocation in patients with allergic asthma. Biomarker analysis showed an attenuation of Th2-regulated inflammatory responses. (Funded by Sterna Biologicals and the German Federal Ministry of Education and Research; ClinicalTrials.gov number, NCT01743768.).

DNA enzymes as potential therapeutics: towards clinical application of 10-23 DNAzymes

INTRODUCTION

Ongoing studies on the inhibition of gene expression at the mRNA level have identified several types of specific inhibitors such as antisense oligonucleotides, small interfering RNA, ribozymes and DNAzymes (Dz). After its discovery in 1997, the 10-23 Dz (which can cleave RNA efficiently and site-specifically, has flexible design, is independent from cell mechanisms, does not require expensive chemical modifications for effective use in vivo) has been employed to downregulate a range of therapeutically important genes. Recently, 10-23 Dzs have taken their first steps into clinical trials.

AREAS COVERED

This review focuses predominantly on Dz applications as potential antiviral, antibacterial, anti-cancer and anti-inflammatory agents as well as for the treatment of cardiovascular disease and diseases of CNS, summarizing results of their clinical trials up to the present day.

EXPERT OPINION

In comparison with antisense oligonucleotides and small interfering RNAs, Dzs do not usually show off-target effects due to their high specificity and lack of immunogenicity in vivo. As more results of clinical trials carried out so far are gradually becoming available, Dzs may turn out to be safe and well-tolerated therapeutics in humans. Therefore, there is a good chance that we may witness a deoxyribozyme drug reaching the clinic in the near future.

Gene silencing: a therapeutic approach to combat influenza virus infections

ABSTRACT 

Selective gene silencing technologies such as RNA interference (RNAi) and nucleic acid enzymes have shown therapeutic potential for treating viral infections. Influenza virus is one of the major public health concerns around the world and its management is challenging due to a rapid increase in antiviral resistance. Influenza vaccine also has its limitations due to the emergence of new strains that may escape the immunity developed by the previous year's vaccine. Antiviral drugs are the primary mode of prevention and control against a pandemic and there is an urgency to develop novel antiviral strategies against influenza virus. In this review, we discuss the potential utility of several gene silencing mechanisms and their prophylactic and therapeutic potential against the influenza virus.

The distribution, clearance, and safety of an anti-MMP-9 DNAzyme in normal and MMTV-PyMT transgenic mice

Catalytic oligonucleotides, known as DNAzymes, are a new class of nucleic acid-based gene therapy that have recently been used in preclinical animal studies to treat various cancers. In this study the systemic distribution, pharmacokinetics, and safety of intravenously administered anti-MMP (matrix metalloproteinase)-9 DNAzyme (AM9D) were determined in healthy FVB and in MMTV-polyoma virus middle T (PyMT) transgenic mice bearing mammary tumors. MMP-9 is known to be involved in tumor cell development, angiogenesis, invasion, and metastasis. Sulfur-35 ((35)S) labeled ([(35)S]-AM9D) administered intravenously, without the use of carrier molecules, to healthy and mammary tumor bearing MMTV-PyMT transgenic mice distributed to all major organs. The order of percentages of [(35)S]-AM9D accumulation in different organs of healthy and MMTV-PyMT mice were blood>liver>kidney>lung>spleen>heart and mammary tumor>blood≈liver>kidney>spleen>lung>heart, respectively. The amount of AM9D accumulated in mammary tumors 2 hours post injection was 0.6% and 0.2% higher than in either blood or liver, respectively, and its rate of initial clearance from mammary tissue was at least 50% slower than the other organs. Approximately 43% of the delivered dosage of [(35)S]-AM9D was cleared from the system via feces and urine over a period of 72 hours. No evidence of acute or chronic cytotoxicity, local or widespread, associated with AM9D treatment (up to 75 mg AM9D /kg of body weight) was observed in the organs examined. These data suggest that DNAzyme in general and AM9D in particular can be used systemically as a therapeutic agent to treat patients with breast cancer or other metastatic and surgically inaccessible tumors.

Biodistribution of the GATA-3-specific DNAzyme hgd40 after inhalative exposure in mice, rats and dogs

The DNAzyme hgd40 was shown to effectively reduce expression of the transcription factor GATA-3 RNA which plays an important role in the regulation of Th2-mediated immune mechanisms such as in allergic bronchial asthma. However, uptake, biodistribution and pharmacokinetics of hgd40 have not been investigated yet. We examined local and systemic distribution of hgd40 in naive mice and mice suffering from experimental asthma. Furthermore, we evaluated the pharmacokinetics as a function of dose following single and repeated administration in rats and dogs. Using intranasal administration of fluorescently labeled hgd40 we demonstrated that the DNAzyme was evenly distributed in inflamed asthmatic mouse lungs within minutes after single dose application. Systemic distribution was investigated in mice using radioactive labeled hgd40. After intratracheal application, highest amounts of hgd40 were detected in the lungs. High amounts were also detected in the bladder indicating urinary excretion as a major elimination pathway. In serum, low systemic hgd40 levels were detected already at 5 min post application (p.a.), subsequently decreasing over time to non-detectable levels at 2h p.a. As revealed by Single Photon Emission Computed Tomography, trace amounts of hgd40 were detectable in lungs up to 7 days p.a. Also in the toxicologically relevant rats and dogs, hgd40 was detectable in blood only shortly after inhalative application. The plasma pharmacokinetic profile was dose and time dependent. Repeated administration did not lead to drug accumulation in plasma of dogs and rats. These pharmacokinetic of hgd40 provide guidance for clinical development, and support an infrequent and convenient dose administration regimen.