MicroRNAs as promising drug delivery target to ameliorate chronic obstructive pulmonary disease using nano-carriers: a comprehensive review

Chronic obstructive pulmonary disease (COPD) is a deteriorating condition triggered by various factors, such as smoking, free radicals, and air pollution. This worsening disease is characterized by narrowing and thickening of airways, painful cough, and dyspnea. In COPD, numerous genes as well as microRNA (miRNA) play a significant role in the pathogenesis of the disease. Many in vivo and in vitro studies suggest that upregulation or suppression of certain miRNAs are effective treatment options for COPD. They have been proven to be more beneficial than the current symptomatic treatments, such as bronchodilators and corticosteroids. MiRNAs play a crucial role in immune cell development and regulate inflammatory responses in various tissues. MiRNA treatment thus allows for precision therapy with improved outcomes. Nanoparticle drug delivery systems such as polymeric nanoparticles, inorganic nanoparticles, dendrimers, polymeric micelles, and liposomes are an efficient method to ensure the biodistribution of the miRNAs to the target site. Identification of the right nanoparticle depending on the requirements and compatibility is essential for achieving maximum therapeutic effect. In this review, we offer a thorough comprehension of the pathology and genetics of COPD and the significance of miRNAs concerning various pathologies of the lung, as potential targets for treating the disease. The present review offers the latest insights into the nanoparticle drug delivery systems that can efficiently carry and deliver miRNA or antagomirs to the specific target site and hence help in effective management of COPD.

Recent trends of NFκB decoy oligodeoxynucleotide-based nanotherapeutics in lung diseases

Nuclear factor κB (NFκB) is a unique protein complex that plays a major role in lung inflammation and respiratory dysfunction. The NFκB signaling pathway, therefore becomes an avenue for the development of potential pharmacological interventions, especially in situations where chronic inflammation is often constitutively active and plays a key role in the pathogenesis and progression of the disease. NFκB decoy oligodeoxynucleotides (ODNs) are double-stranded and carry NFκB binding sequences. They prevent the formation of NFκB-mediated inflammatory cytokines and thus have been employed in the treatment of a variety of chronic inflammatory diseases. However, the systemic administration of naked decoy ODNs restricts their therapeutic effectiveness because of their poor pharmacokinetic profile, instability, degradation by cellular enzymes and their low cellular uptake. Both structural modification and nanotechnology have shown promising results in enhancing the pharmacokinetic profiles of potent therapeutic substances and have also shown great potential in the treatment of respiratory diseases such as asthma, chronic obstructive pulmonary disease and cystic fibrosis. In this review, we examine the contribution of NFκB activation in respiratory diseases and recent advancements in the therapeutic use of decoy ODNs. In addition, we also highlight the limitations and challenges in use of decoy ODNs as therapeutic molecules, cellular uptake of decoy ODNs, and the current need for novel delivery systems to provide efficient delivery of decoy ODNs. Furthermore, this review provides a common platform for discussion on the existence of decoy ODNs, as well as outlining perspectives on the latest generation of delivery systems that encapsulate decoy ODNs and target NFκB in respiratory diseases.

Oligonucleotide therapy: An emerging focus area for drug delivery in chronic inflammatory respiratory diseases

Oligonucleotide-based therapies are advanced novel interventions used in the management of various respiratory diseases such as asthma and Chronic Obstructive Pulmonary Disease (COPD). These agents primarily act by gene silencing or RNA interference. Better methodologies and techniques are the need of the hour that can deliver these agents to tissues and cells in a target specific manner by which their maximum potential can be reached in the management of chronic inflammatory diseases. Nanoparticles play an important role in the target-specific delivery of drugs. In addition, oligonucleotides also are extensively used for gene transfer in the form of polymeric, liposomal and inorganic carrier materials. Therefore, the current review focuses on various novel dosage forms like nanoparticles, liposomes that can be used efficiently for the delivery of various oligonucleotides such as siRNA and miRNA. We also discuss the future perspectives and targets for oligonucleotides in the management of respiratory diseases.

Mechanisms of Antisense Transcription Initiation with Implications in Gene Expression, Genomic Integrity and Disease Pathogenesis

Non-coding antisense transcripts arise from the strand opposite the sense strand. Over 70% of the human genome generates non-coding antisense transcripts while less than 2% of the genome codes for proteins. Antisense transcripts and/or the act of antisense transcription regulate gene expression and genome integrity by interfering with sense transcription and modulating histone modifications or DNA methylation. Hence, they have significant pathological and physiological relevance. Indeed, antisense transcripts were found to be associated with various diseases including cancer, diabetes, cardiac and neurodegenerative disorders, and, thus, have promising potentials for prognostic and diagnostic markers and therapeutic development. However, it is not clearly understood how antisense transcription is initiated and epigenetically regulated. Such knowledge would provide new insights into the regulation of antisense transcription, and hence disease pathogenesis with therapeutic development. The recent studies on antisense transcription initiation and its epigenetic regulation, which are limited, are discussed here. Furthermore, we concisely describe how antisense transcription/transcripts regulate gene expression and genome integrity with implications in disease pathogenesis and therapeutic development.

Characterization of oligonucleotide aptamers targeting the 5'-UTR from dengue virus

AIM

The dengue virus is responsible for a high worldwide incidence of infections, aggravated by late diagnosis, and often confused with other tropical diseases. Results/methodology: Oligonucleotide aptamers binding to the 5'-UTR from dengue virus selected after eight rounds by systematic evolution of ligands by exponential enrichment technology were analyzed by dot-blot assay and in silico prediction of secondary structures, demonstrating the presence of stem-loops that may have the potential for interaction with the viral genome, which can lead to loss of their original conformation.

CONCLUSION

This is the first description of RNA aptamers against functional RNA elements of the dengue virus genome with implications for disease control, which may have potential as tools in the future of antiviral therapies and for diagnostics.

Barriers to inhaled gene therapy of obstructive lung diseases: A review

Knowledge of genetic origins of obstructive lung diseases has made inhaled gene therapy an attractive alternative to the current standards of care that are limited to managing disease symptoms. Initial lung gene therapy clinical trials occurred in the early 1990s following the discovery of the genetic defect responsible for cystic fibrosis (CF), a monogenic disorder. However, despite over two decades of intensive effort, gene therapy has yet to help patients with CF or any other obstructive lung disease. The slow progress is due in part to poor understanding of the biological barriers to inhaled gene therapy. Encouragingly, clinical trials have shown that inhaled gene therapy with various viral vectors and non-viral gene vectors is well tolerated by patients, and continued research has provided valuable lessons and resources that may lead to future success of this therapeutic strategy. In this review, we first introduce representative obstructive lung diseases and examine limitations of currently available therapeutic options. We then review key components for successful execution of inhaled gene therapy, including gene delivery systems, primary physiological barriers and strategies to overcome them, and advances in preclinical disease models with which the most promising systems may be identified for human clinical trials.

Large Porous Particles for Sustained Release of a Decoy Oligonucelotide and Poly(ethylenimine): Potential for Combined Therapy of Chronic Pseudomonas aeruginosa Lung Infections

We have recently demonstrated that the specific inhibition of nuclear factor-κB by a decoy oligonucleotide (dec-ODN) delivered through inhalable large porous particles (LPP) made of poly(lactic-co-glycolic acid) (PLGA) may be highly beneficial for long-term treatment of lung inflammation. Nevertheless, besides chronic inflammation, multifunctional systems aimed to control also infection are required in chronic lung diseases, such as cystic fibrosis (CF). In this work, we tested the hypothesis that engineering PLGA-based LPP with branched poly(ethylenimine) (PEI) may improve LPP properties for pulmonary delivery of dec-ODN, with particular regard to the treatment of Pseudomonas aeruginosa lung infections. After getting insight into the role of PEI on the technological properties of PLGA-based LPP for delivery of dec-ODN, the putative synergistic effect of PEI free or PEI released from LPP on in vitro antimicrobial activity of tobramycin (Tb) and aztreonam (AZT) against P. aeruginosa was elucidated. Meanwhile, cytotoxicity studies on A549 cells were carried out. Results clearly demonstrate that the dry powders have promising aerosolization properties and afford a prolonged in vitro release of both dec-ODN and PEI. The encapsulation of PEI into LPP results in a 2-fold reduction of the minimum inhibitory concentration of AZT, while reducing the cytotoxic effect of PEI. Of note, the developed ODN/PLGA/PEI LPP persisted at lung at least for 14 days after intratracheal administration in rats where they can provide sustained and combined release of dec-ODN and PEI. dec-ODN will likely act as an anti-inflammatory drug, while PEI may enhance the therapeutic activity of inhaled antibiotics, which are commonly employed for the treatment of concomitant lung infections.

Regulation of Antisense Transcription by NuA4 Histone Acetyltransferase and Other Chromatin Regulatory Factors

NuA4 histone lysine (K) acetyltransferase (KAT) promotes transcriptional initiation of TATA-binding protein (TBP)-associated factor (TAF)-dependent ribosomal protein genes. TAFs have also been recently found to enhance antisense transcription from the 3' end of the GAL10 coding sequence. However, it remains unknown whether, like sense transcription of the ribosomal protein genes, TAF-dependent antisense transcription of GAL10 also requires NuA4 KAT. Here, we show that NuA4 KAT associates with the GAL10 antisense transcription initiation site at the 3' end of the coding sequence. Such association of NuA4 KAT depends on the Reb1p-binding site that recruits Reb1p activator to the GAL10 antisense transcription initiation site. Targeted recruitment of NuA4 KAT to the GAL10 antisense transcription initiation site promotes GAL10 antisense transcription. Like NuA4 KAT, histone H3 K4/36 methyltransferases and histone H2B ubiquitin conjugase facilitate GAL10 antisense transcription, while the Swi/Snf and SAGA chromatin remodeling/modification factors are dispensable for antisense, but not sense, transcription of GAL10. Taken together, our results demonstrate for the first time the roles of NuA4 KAT and other chromatin regulatory factors in controlling antisense transcription, thus illuminating chromatin regulation of antisense transcription.

Improving the efficacy of inhaled drugs in cystic fibrosis: challenges and emerging drug delivery strategies

Cystic fibrosis (CF) is the most common autosomal recessive disease in Caucasians associated with early death. Although the faulty gene is expressed in epithelia throughout the body, lung disease is still responsible for most of the morbidity and mortality of CF patients. As a local delivery route, pulmonary administration represents an ideal way to treat respiratory infections, excessive inflammation and other manifestations typical of CF lung disease. Nonetheless, important determinants of the clinical outcomes of inhaled drugs are the concentration/permanence at the lungs as well as the ability of the drug to overcome local extracellular and cellular barriers. This review focuses on emerging delivery strategies used for local treatment of CF pulmonary disease. After a brief description of the disease and formulation rules dictated by CF lung barriers, it describes current and future trends in inhaled drugs for CF. The most promising advanced formulations are discussed, highlighting the advantages along with the major challenges for researchers working in this field.

Nonhuman targets in allergic lung conditions

Existing therapies for allergic asthma are far from perfect: the global prevalence of disease increases despite them and they are poorly effective in dealing with the exacerbations that account for hospitalization and asthma deaths. Commercially, there are pressures on these existing medicines too--a growing threat from generics and reluctance by payers to reimburse for increasingly marginal improvements in medicines with precedented mechanisms. Experience shows that attempts to devise selective small-molecule interventions directed at the myriad of downstream effector pathways has not been a fertile ground for the development of effective new medicines. An alternative strategy, exploiting breakthroughs in understanding the molecular basis of allergenicity and the key role of innate immune mechanisms in asthma, is to direct new approaches to the disease triggers themselves: allergens. This raises interesting possibilities for anti-Lipinski drug design (extracellular nonhuman targets, inhaled delivery) and creates unprecedented pharmacological opportunities in the therapeutic area.

The Novartis view on emerging drugs and novel targets for the treatment of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a debilitating lung disease characterized by airflow limitation and chronic inflammation in the lungs. The mainstay of drug therapy for COPD is represented by long-acting bronchodilators, an important aspect of Novartis' development program. Novel once-daily dosing bronchodilators, such as the long-acting muscarinic antagonist (LAMA) glycopyrronium and the LAMA/long-acting β2-agonist (LABA) fixed-dose combination QVA149, have been shown to provide significant benefits to patients with COPD in terms of improvement in lung function, exercise tolerance, health-related quality of life, symptoms and reduction in the rate of exacerbations. Despite the benefits provided by these new treatment options, prevention of disease progression and control of exacerbations in certain patient phenotypes remain key challenges in the treatment of COPD. In order to address these needs and gain new insights into the complexity of COPD, Novartis is, in addition to bronchodilator-only therapies, developing LABA/inhaled corticosteroids (ICS) combinations to target inflammation, such as QMF149, as well as non-steroid based anti-inflammatory agents against key novel targets. These commitments are central to the Novartis' final goal of improving the standard of care in respiratory medicine and offering a better quality of life to patients with COPD.

The pharmacological modulation of allergen-induced asthma

Aeroallergens are the most common triggers for the development of asthma. Recent birth cohort studies have identified viral infections occurring against a background of aeroallergen sensitization as a potent risk factor for initiation of asthma. Viral infection enhances immunopathogenic potential of pre-existing inhalant allergy via modulating airway mucosal dendritic cells. By using an allergen inhalation challenge clinical model, studies have shown that the late asthma response (LAR) is associated with more pronounced allergen-induced airway inflammation and airway hyperresponsiveness. The degree of airway eosinophilia, regulated by bone marrow progenitor cells and interleukin-5 level, correlates with the magnitude of the LAR and the increase in hyperresponsiveness. Both myeloid and plasmacytoid dendritic cell subsets have been involved in the pathogenesis of allergen-induced LAR. Myeloid dendritic cells are responsible for the allergen presentation and induction of inflammation and plasmacytoid dendritic cells play a role in the resolution of allergen-induced inflammation. A variety of potential new classes of asthma medication has also been evaluated with the allergen inhalation challenge in mild asthmatic subjects. Examples are TPI ASM8, an inhaled anti-sense oligonucleotide drug product, which attenuated both early and LARs via inhibition of the target gene mRNA of chemokine receptor 3, and the common β chain of interleukin-3, interleukin-5 and granulocyte-macrophage colony-stimulating factor receptor. Anti-human antibody interleukin-13 (IM-638) significantly attenuated both early and late allergen-induced asthma response. Pitrakinra, which targets both interleukin-4 and interleukin-13, substantially diminishes allergen-induced airway responses. Allergen-induced airway responses are a valuable way to evaluate the activity of possible new therapies in asthmatic airways.

PEI-engineered respirable particles delivering a decoy oligonucleotide to NF-κB: inhibiting MUC2 expression in LPS-stimulated airway epithelial cells

A specific and promising approach to limit inflammation and mucin iperproduction in chronic lung diseases relies on specific inhibition of nuclear Factor-κB (NF-κB) by a decoy oligonucleotide (dec-ODN). To fulfill the requirements dictated by translation of dec-ODN therapy in humans, inhalable dry powders were designed on a rational basis to provide drug protection, sustained release and to optimize pharmacological response. To this end, large porous particles (LPP) for dec-ODN delivery made of a sustained release biomaterial (poly(lactic-co-glycolic) acid, PLGA) and an “adjuvant” hydrophilic polymer (polyethylenimine, PEI) were developed and their effects on LPS-stimulated human airway epithelial cells evaluated. The composite PLGA/PEI particles containing dec-ODN (i.e., LPP_PEI) were successfully engineered for widespread deposition in the lung and prolonged release of intact dec-ODN in vitro. LPP_PEI caused a prolonged inhibition of IL-8 and MUC2 expression in CF human bronchial epithelial cells and human epithelial pulmonary NCI-H292 cells, respectively, as compared to naked dec-ODN. Nonetheless, as compared to previously developed LPP, the presence of PEI was essential to construct a dec-ODN delivery system able to act in mucoepidermoid lung epithelial cells. In perspective, engineering LPP with PEI may become a key factor for tuning carrier properties, controlling lung inflammation and mucin production which, in turn, can foster in vivo translation of dec-ODN therapy.