Anti-inflammatory activity of inhaled IL-4 receptor-alpha antisense oligonucleotide in mice

Current and future therapeutic approaches of CFTR and airway dysbiosis in an era of personalized medicine

Cystic fibrosis (CF) is a life-threatening genetic disorder caused by mutations in the CFTR gene. This leads to a defective protein that impairs chloride transport, resulting in thick mucus buildup and chronic inflammation in the airways. The review discusses current and future therapeutic approaches for CFTR dysfunction and airway dysbiosis in the era of personalized medicine. Personalized medicine has revolutionized CF treatment with the advent of CFTR modulator therapies that target specific genetic mutations. These therapies have significantly improved patient outcomes, slowing disease progression, and enhancing quality of life. It also highlights the growing recognition of the airway microbiome's role in CF pathogenesis and discusses strategies to modulate the microbiome to further improve patient outcomes. This review discusses various therapeutic approaches for cystic fibrosis (CFTR) mutations, including adenovirus gene treatments, nonviral vectors, CRISPR/cas9 methods, RNA replacement, antisense-oligonucleotide-mediated DNA-based therapies, and cell-based therapies. It also introduces airway dysbiosis with CF and how microbes influence the lungs. The review highlights the importance of understanding the cellular and molecular causes of CF and the development of personalized medicine to improve quality of life and health outcomes.

Potential of oligonucleotide- and protein/peptide-based therapeutics in the management of toxicant/stressor-induced diseases

Exposure to toxicants/stressors has been linked to the development of many human diseases. They could affect various cellular components, such as DNA, proteins, lipids, and non-coding RNAs (ncRNA), thereby triggering various cellular pathways, particularly oxidative stress, inflammatory responses, and apoptosis, which can contribute to pathophysiological states. Accordingly, modulation of these pathways has been the focus of numerous investigations for managing related diseases. The involvement of various ncRNAs, such as small interfering RNA (siRNA), microRNAs (miRNA), and long non-coding RNAs (lncRNA), as well as various proteins and peptides in mediating these pathways, provides many target sites for pharmaceutical intervention. In this regard, various oligonucleotide- and protein/peptide-based therapies have been developed to treat toxicity-induced diseases, which have shown promising results in vitro and in vivo. This comprehensive review provides information about various aspects of toxicity-related diseases including their causing factors, main underlying mechanisms and intermediates, and their roles in pathophysiological states. Particularly, it highlights the principles and mechanisms of oligonucleotide- and protein/peptide-based therapies in the treatment of toxicity-related diseases. Furthermore, various issues of oligonucleotides and proteins/peptides for clinical usage and potential solutions are discussed.

RNA therapeutics for respiratory diseases

It has become increasingly common to utilize RNA treatment to treat respiratory illnesses. Experimental research on both people and animals has advanced quickly since the turn of the twenty-first century in an effort to discover a treatment for respiratory ailments that could not be accomplished with earlier techniques, specifically in treating prevalent respiratory diseases such as lung cancer, chronic obstructive pulmonary disease (COPD), respiratory infections caused by viruses, and asthma. This chapter has provided a comprehensive overview of the scientific evidence in applying RNA therapy to treat respiratory diseases. The chapter describes the development of this therapy for respiratory diseases. At the same time, the types of RNA therapy for respiratory diseases have been highlighted. In addition, the mechanism of this therapy for respiratory diseases has also been covered. These insights are indispensable if this therapy is to be developed widely.

Advances in Nucleic Acid Research: Exploring the Potential of Oligonucleotides for Therapeutic Applications and Biological Studies

In recent years, nucleic acids have emerged as powerful biomaterials, revolutionizing the field of biomedicine. This review explores the multifaceted applications of nucleic acids, focusing on their pivotal role in various biomedical applications. Nucleic acids, including deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), possess unique properties such as molecular recognition ability, programmability, and ease of synthesis, making them versatile tools in biosensing and for gene regulation, drug delivery, and targeted therapy. Their compatibility with chemical modifications enhances their binding affinity and resistance to degradation, elevating their effectiveness in targeted applications. Additionally, nucleic acids have found utility as self-assembling building blocks, leading to the creation of nanostructures whose high order underpins their enhanced biological stability and affects the cellular uptake efficiency. Furthermore, this review delves into the significant role of oligonucleotides (ODNs) as indispensable tools for biological studies and biomarker discovery. ODNs, short sequences of nucleic acids, have been instrumental in unraveling complex biological mechanisms. They serve as probes for studying gene expression, protein interactions, and cellular pathways, providing invaluable insights into fundamental biological processes. By examining the synergistic interplay between nucleic acids as powerful biomaterials and ODNs as indispensable tools for biological studies and biomarkers, this review highlights the transformative impact of these molecules on biomedical research. Their versatile applications not only deepen our understanding of biological systems but also are the driving force for innovation in diagnostics and therapeutics, ultimately advancing the field of biomedicine.

Stability of Naked Nucleic Acids under Physical Treatment and Powder Formation: Suitability for Development as Dry Powder Formulations for Inhalation

A number of functional nucleic acids, including plasmid DNA (pDNA) and small interfering RNA (siRNA), have been attracting increasing attention as new therapeutic modalities worldwide. Dry pDNA and siRNA powder formulations for inhalation are considered practical in clinical applications for respiratory diseases. However, physical stresses in the powder-forming process may destabilize nucleic acids, particularly when vectors with stabilizing effects are not used. We herein compare the stability of naked pDNA and siRNA through various physical treatments and two powder-forming processes. The structural and functional integrities of pDNA were markedly reduced via sonication, heating, and atomization, whereas those of siRNA were preserved throughout all of the physical treatments investigated. Spray-dried and spray-freeze-dried powders of siRNA maintained their structural and functional integrities, whereas those of pDNA did not. These results demonstrate that siRNA is more suitable for powder formation in the naked state than pDNA due to its higher stability under physical treatments. Furthermore, a spray-freeze-dried powder with a high content of naked siRNA (12% of the powder) was successfully produced that preserved its structural and functional integrities, achieving high aerosol performance with a fine particle fraction of approximately 40%.

Delivery Characterization of SPL84 Inhaled Antisense Oligonucleotide Drug for 3849 + 10 kb C- > T Cystic Fibrosis Patients

Recent advances in the therapeutic potential of RNA-related treatments, specifically for antisense oligonucleotide (ASO)-based drugs, have led to increased numbers of ASO regulatory approvals. In this study, we focus on SPL84, an inhaled ASO-based drug, developed for the treatment of the pulmonary disease cystic fibrosis (CF). Pulmonary drug delivery is challenging, due to a variety of biological, physical, chemical, and structural barriers, especially when targeting the cell nucleus. The distribution of SPL84 throughout the lungs, penetration into the epithelial cells and nucleus, and structural stability are critical parameters that will impact drug efficacy in a clinical setting. In this study, we demonstrate broad distribution, as well as cell and nucleus penetration of SPL84 in mouse and monkey lungs. In vivo and in vitro studies confirmed the stability of our inhaled drug in CF patient-derived mucus and in lung lysosomal extracts. The mobility of SPL84 through hyperconcentrated mucus was also demonstrated. Our results, supported by a promising preclinical pharmacological effect of full restoration of cystic fibrosis transmembrane conductance regulator channel activity, emphasize the high potential of SPL84 as an effective drug for the treatment of CF patients. In addition, successfully tackling the lung distribution of SPL84 offers immense opportunities for further development of SpliSense's inhaled ASO-based drugs for unmet needs in pulmonary diseases.

Gene Therapy for Immunoglobulin E, Complement-Mediated, and Eosinophilic Disorders

Immunoglobulin E, complement, and eosinophils play an important role in host defense, but dysfunction of each of these components can lead to a variety of human disorders. In this review, we summarize how investigators have adapted gene therapy and antisense technology to modulate immunoglobulin E, complement, and/or eosinophil levels to treat these disorders.

Empagliflozin inhibits autophagy and mitigates airway inflammation and remodelling in mice with ovalbumin-induced allergic asthma

Empagliflozin, a selective inhibitor of Na⁺-glucose cotransporter-2, has been reported to exert anti-inflammatory and anti-fibrotic effects in addition to autophagy modulation. Addressing the role of autophagy in allergic asthma revealed controversial results. The potential effect of empagliflozin treatment on airway inflammation and remodelling as well as autophagy modulation in a murine model of allergic asthma was investigated. Over a 7-week period, male BALB/c mice were sensitized and challenged by intraperitoneal injection and inhalation of ovalbumin, respectively. Animals were treated with empagliflozin (10 mg/kg; orally) and/or rapamycin (an autophagy inducer; 4 mg/kg; intraperitoneally) before every challenge. Methacholine-induced airway hyperresponsiveness was evaluated one day after the last challenge. After euthanasia, serum, bronchoalveolar lavage fluid, and lung tissues were collected for biochemical, histopathological, and immunohistochemical assessment. Results revealed that empagliflozin decreased airway hyperresponsiveness, serum ovalbumin-specific immunoglobulin E, and bronchoalveolar lavage total and differential leukocytic counts. Levels of inflammatory and profibrotic cytokines (IL-4, IL-5, IL-13, IL-17, and transforming growth factor-β1) were all inhibited. Moreover, empagliflozin preserved pulmonary microscopic architecture and alleviated bronchiolar epithelial thickening, goblet cell hyperplasia, fibrosis and smooth muscle hypertrophy. These effects were associated with inhibition of ovalbumin-activated autophagic flux, as demonstrated by decreased LC3B expression and LC3BII/I ratio, as well as increased P62 expression. However, the therapeutic potential of empagliflozin was inhibited when rapamycin was co-administered. In conclusion, this study demonstrates that empagliflozin has immunomodulatory, anti-inflammatory, and anti-remodelling properties in ovalbumin-induced allergic asthma and suggests that autophagic flux inhibition may play a role in empagliflozin's anti-asthmatic effects.

Gene, RNA, and ASO-based therapeutic approaches in Cystic Fibrosis

Most people with Cystic Fibrosis (PwCF) harbor Cystic Fibrosis Transmembrane Conductance (CFTR) mutations that respond to highly effective CFTR modulators (HEM); however, a small fraction of non-responsive variants will require alternative approaches for treatment. Furthermore, the long-term goal to develop a cure for CF will require novel therapeutic strategies. Nucleic acid-based approaches offer the potential to address all CF-causing mutations and possibly a cure for all PwCF. In this minireview, we discuss current knowledge, recent progress, and critical questions surrounding the topic of Gene-, RNA-, and ASO-based therapies for the treatment of Cystic Fibrosis (CF).

The Promising Therapeutic Potential of Oligonucleotides for Pulmonary Fibrotic Diseases

INTRODUCTION

Fibrotic lung diseases represent a large subset of diseases with an unmet clinical need. Oligonucleotide therapies (ONT) are a promising therapeutic approach for the treatment of pulmonary disease as they can inhibit pathways that are otherwise difficult to target. Additionally, targeting the lung specifically with ONT is advantageous because it reduces the possibilities of systemic side effects and tolerability concerns.

AREAS COVERED

This review presents the chemical basis of designing various ONTs currently known to treat fibrotic lung diseases. Further, the authors have also discussed the delivery vehicle, routes of administration, physiological barriers of the lung, and toxicity concerns with ONTs.

EXPERT OPINION

ONTs provide a promising therapeutic approach for the treatment of fibrotic diseases of the lung, particularly because ONTs directly delivered to the lung show little systemic side effects compared to current therapeutic strategies. Dry powder aerosolized inhalers may be a good strategy for getting ONTs into the lung in humans. However, as of now, no dry powder ONTs have been approved for use in the clinical setting, and this challenge must be overcome for future therapies. Various delivery methods that can aid in direct targeting may also improve the use of ONTs for lung fibrotic diseases.

Antisense oligonucleotides targeting ORF1b block replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

The ongoing COVID-19 pandemic continues to pose a need for new and efficient therapeutic strategies. We explored antisense therapy using oligonucleotides targeting the severe acute respiratory syndrome coronavirus (SARS-CoV-2) genome. We predicted in silico four antisense oligonucleotides (ASO gapmers with 100% PTO linkages and LNA modifications at their 5' and 3'ends) targeting viral regions ORF1a, ORF1b, N and the 5'UTR of the SARS-CoV-2 genome. Efficiency of ASOs was tested by transfection in human ACE2-expressing HEK-293T cells and monkey VeroE6/TMPRSS2 cells infected with SARS-CoV-2. The ORF1b-targeting ASO was the most efficient, with a 71% reduction in the number of viral genome copies. N- and 5'UTR-targeting ASOs also significantly reduced viral replication by 55 and 63%, respectively, compared to non-related control ASO (ASO-C). Viral titration revealed a significant decrease in SARS-CoV-2 multiplication both in culture media and in cells. These results show that anti-ORF1b ASO can specifically reduce SARS-CoV-2 genome replication in vitro in two different cell infection models. The present study presents proof-of concept of antisense oligonucleotide technology as a promising therapeutic strategy for COVID-19.

Sustained inhibition of ENaC in CF: Potential RNA-based therapies for mutation-agnostic treatment

Disruption of the equilibrium between ion secretion and absorption processes by the airway epithelium is central to many muco-obstructive lung diseases including cystic fibrosis (CF). Besides correction of defective folding and function of CFTR, inhibition of amiloride-sensitive epithelia sodium channels (ENaC) has emerged as a bona fide therapeutic strategy to improve mucociliary clearance in patients with CF. The short half-life of amiloride-based ENaC blockers and hyperosmotic therapies have led to the development of novel RNA-based interventions for targeted and sustained reduction of ENaC expression and function in preclinical models of CF. This review summarizes the recent advances in RNA therapeutics targeting ENaC for mutation-agnostic treatment of CF.

Antisense oligonucleotides: recent progress in the treatment of various diseases

Background

Antisense oligonucleotides are a promising novel class of therapeutic agents to treat different diseases in living things. They provide an efficient method for making target-selective agents because they change gene expression sequences. Therefore, the malfunctioning protein could be stopped, and the source of disease would be obliterated. The existing reviews of antisense oligonucleotides are focusing on discovery, development and concept. However, there is no review paper concerning the latest development of antisense oligonucleotides and their different therapeutic uses. Therefore, the present work has been targeting a comprehensive summary of newly synthesized antisense oligonucleotides and their biological activities.

Main body

Antisense oligonucleotides are different from traditional therapeutic agents that are planned to interact with mRNA and modulate protein expression through a unique mechanism of action. In the last three decades, several researchers revealed the newer antisense oligonucleotides found with a high therapeutic profile due to more selective action on the drug target and thus producing a lesser side effect and low toxicity. This review emphasizes the research work on antisense oligonucleotides and their therapeutic activities.

Short conclusion

With the support of the literature review, here we enlisted various antisense oligonucleotides that were prepared by appropriate technique and explored their pharmacological activities. To the best of our knowledge, it is the right time to consider the antisense oligonucleotides as a perfect choice of treatment for different diseases due to conceptual simplicity, more selective action, lesser side effects, low toxicity and permanent cure.

Graphical abstract

Open reading frame correction using splice-switching antisense oligonucleotides for the treatment of cystic fibrosis

CFTR gene mutations that result in the introduction of premature termination codons (PTCs) are common in cystic fibrosis (CF). This mutation type causes a severe form of the disease, likely because of low CFTR messenger RNA (mRNA) expression as a result of nonsense-mediated mRNA decay, as well as the production of a nonfunctional, truncated CFTR protein. Current therapeutics for CF, which target residual protein function, are less effective in patients with these types of mutations due in part to low CFTR protein levels. Splice-switching antisense oligonucleotides (ASOs), designed to induce skipping of exons in order to restore the mRNA open reading frame, have shown therapeutic promise preclinically and clinically for a number of diseases. We hypothesized that ASO-mediated skipping of CFTR exon 23 would recover CFTR activity associated with terminating mutations in the exon, including CFTR p.W1282X, the fifth most common mutation in CF. Here, we show that CFTR lacking the amino acids encoding exon 23 is partially functional and responsive to corrector and modulator drugs currently in clinical use. ASO-induced exon 23 skipping rescued CFTR expression and chloride current in primary human bronchial epithelial cells isolated from a homozygote CFTR-W1282X patient. These results support the use of ASOs in treating CF patients with CFTR class I mutations in exon 23 that result in unstable CFTR mRNA and truncations of the CFTR protein.

The mixture of siRNAs targeted to IL-4 and IL-13 genes effectively reduces the airway hyperreactivity and allergic inflammation in a mouse model of asthma

Bronchial asthma (BA) is one of the most common chronic inflammatory disease of airways. There are huge experimental data indicating that Th2-cytokines IL-4 and IL-13 play a key role in BA pathogenesis. They are implicated in the IgE synthesis, eosinophil infiltration to the lungs and in the development of airway hyperreactivity (AHR), that makes these cytokines the promising targets. Neutralization of IL-4 and IL-13 or its common receptor chain (IL-4Rα) by monoclonal antibodies substantially reduce asthma symptoms. RNA interference provides a novel method for regulation of gene expression by siRNA molecules. In this study we evaluated whether the siRNA targeted to IL-4 and IL-13 reduce BA symptoms in mice model. Experimental BA was induced in BALB/c mice by sensitization to ovalbumin allergen followed by intranasal challenge. The intranasal delivery of siRNAs targeted to IL-4 and IL-13 inhibited the lung expression of these cytokines by more than 50% that led to the attenuation of AHR and pulmonary inflammation; the quantity of eosinophils in lungs which are one of the major inflammatory cells involved in allergic asthma pathogenesis decreased by more than 50% after siRNA treatment. These data support the possibility of a dual IL-4 and IL-13 inhibition by locally delivered siRNAs which in turn leads to the suppression of allergen-induced pulmonary inflammation and AHR.

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.

Nanomedicine-based delivery strategies for nucleic acid gene inhibitors in inflammatory diseases

Thanks to their abilities to modulate the expression of virtually any genes, RNA therapeutics have attracted considerable research efforts. Among the strategies focusing on nucleic acid gene inhibitors, antisense oligonucleotides and small interfering RNAs have reached advanced clinical trial phases with several of them having recently been marketed. These successes were obtained by overcoming stability and cellular delivery issues using either chemically modified nucleic acids or nanoparticles. As nucleic acid gene inhibitors are promising strategies to treat inflammatory diseases, this review focuses on the barriers, from manufacturing issues to cellular/subcellular delivery, that still need to be overcome to deliver the nucleic acids to sites of inflammation other than the liver. Furthermore, key examples of applications in rheumatoid arthritis, inflammatory bowel, and lung diseases are presented as case studies of systemic, oral, and lung nucleic acid delivery.

Antisense oligonucleotide-based drug development for Cystic Fibrosis patients carrying the 3849+10 kb C-to-T splicing mutation

Background:

Antisense oligonucleotide (ASO)-based drugs for splicing modulation were recently approved for various genetic diseases with unmet need. Here we aimed to develop an ASO-based splicing modulation therapy for Cystic Fibrosis (CF) patients carrying the 3849 + 10 kb C-to-T splicing mutation in the CFTR gene.

Methods:

We have screened, in FRT cells expressing the 3849 + 10 kb C-to-T splicing mutation, ~30 2ʹ-O-Methyl-modified phosphorothioate ASOs, targeted to prevent the recognition and inclusion of a cryptic exon generated due to the mutation. The effect of highly potent ASO candidates on the splicing pattern, protein maturation and CFTR function was further analyzed in well differentiated primary human nasal and bronchial epithelial cells, derived from patients carrying at least one 3849 + 10 kb C-to-T allele.

Results:

A highly potent lead ASO, efficiently delivered by free uptake, was able to significantly increase the level of correctly spliced mRNA and completely restore the CFTR function to wild type levels in cells from a homozygote patient. This ASO led to CFTR function with an average of 43% of wild type levels in cells from various heterozygote patients. Optimized efficiency of the lead ASO was further obtained with 2ʹ-Methoxy Ethyl modification (2ʹMOE).

Conclusion:

The highly efficient splicing modulation and functional correction, achieved by free uptake of the selected lead ASO in various patients, demonstrate the ASO therapeutic potential benefit for CF patients carrying splicing mutations and is aimed to serve as the basis for our current clinical development.

Overcoming the challenges of tissue delivery for oligonucleotide therapeutics

Synthetic therapeutic oligonucleotides (STO) represent the third bonafide platform for drug discovery in the pharmaceutical industry after small molecule and protein therapeutics. So far, thirteen STOs have been approved by regulatory agencies and over one hundred of them are in different stages of clinical trials. STOs hybridize to their target RNA or DNA in cells via Watson-Crick base pairing to exert their pharmacological effects. This unique class of therapeutic agents has the potential to target genes and gene products that are considered undruggable by other therapeutic platforms. However, STOs must overcome several extracellular and intracellular obstacles to interact with their biological RNA targets inside cells. These obstacles include degradation by extracellular nucleases, scavenging by the reticuloendothelial system, filtration by the kidney, traversing the capillary endothelium to access the tissue interstitium, cell-surface receptor-mediated endocytic uptake, and escape from endolysosomal compartments to access the nuclear and/or cytoplasmic compartments where their targets reside. In this review, we present the recent advances in this field with a specific focus on antisense oligonucleotides (ASOs) and siRNA therapeutics.

Antisense technology: an overview and prospectus

Antisense technology is now beginning to deliver on its promise to treat diseases by targeting RNA. Nine single-stranded antisense oligonucleotide (ASO) drugs representing four chemical classes, two mechanisms of action and four routes of administration have been approved for commercial use, including the first RNA-targeted drug to be a major commercial success, nusinersen. Although all the approved drugs are for use in patients with rare diseases, many of the ASOs in late- and middle-stage clinical development are intended to treat patients with very common diseases. ASOs in development are showing substantial improvements in potency and performance based on advances in medicinal chemistry, understanding of molecular mechanisms and targeted delivery. Moreover, the ASOs in development include additional mechanisms of action and routes of administration such as aerosol and oral formulations. Here, we describe the key technological advances that have enabled this progress and discuss recent clinical trials that illustrate the impact of these advances on the performance of ASOs in a wide range of therapeutic applications. We also consider strategic issues such as target selection and provide perspectives on the future of the field.

Antisense technology: A review

Antisense technology is beginning to deliver on the broad promise of the technology. Ten RNA-targeted drugs including eight single-strand antisense drugs (ASOs) and two double-strand ASOs (siRNAs) have now been approved for commercial use, and the ASOs in phase 2/3 trials are innovative, delivered by multiple routes of administration and focused on both rare and common diseases. In fact, two ASOs are used in cardiovascular outcome studies and several others in very large trials. Interest in the technology continues to grow, and the field has been subject to a significant number of reviews. In this review, we focus on the molecular events that result in the effects observed and use recent clinical results involving several different ASOs to exemplify specific molecular mechanisms and specific issues. We conclude with the prospective on the technology.

Antisense oligonucleotide-mediated correction of CFTR splicing improves chloride secretion in cystic fibrosis patient-derived bronchial epithelial cells

Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, encoding an anion channel that conducts chloride and bicarbonate across epithelial membranes. Mutations that disrupt pre-mRNA splicing occur in >15% of CF cases. One common CFTR splicing mutation is CFTR c.3718-2477C>T (3849+10 kb C>T), which creates a new 5′ splice site, resulting in splicing to a cryptic exon with a premature termination codon. Splice-switching antisense oligonucleotides (ASOs) have emerged as an effective therapeutic strategy to block aberrant splicing. We test an ASO targeting the CFTR c.3718-2477C>T mutation and show that it effectively blocks aberrant splicing in primary bronchial epithelial (hBE) cells from CF patients with the mutation. ASO treatment results in long-term improvement in CFTR activity in hBE cells, as demonstrated by a recovery of chloride secretion and apical membrane conductance. We also show that the ASO is more effective at recovering chloride secretion in our assay than ivacaftor, the potentiator treatment currently available to these patients. Our findings demonstrate the utility of ASOs in correcting CFTR expression and channel activity in a manner expected to be therapeutic in patients.

Antisense drug discovery and development technology considered in a pharmacological context

When coined, the term "antisense" included oligonucleotides of any structure, with any chemical modification and designed to work through any post-RNA hybridization mechanism. However, in practice the term "antisense" has been used to describe single stranded oligonucleotides (ss ASOs) designed to hybridize to RNAswhile the term "siRNA" has come to mean double stranded oligonucleotides designed to activate Ago2. However, the two approaches share many common features. The medicinal chemistry developed for ASOs greatly facilitated the development of siRNA technology and remains the chemical basis for both approaches. Many of challenges faced and solutions achieved share many common features. In fact, because ss ASOs can be designed to activate Ago2, the two approaches intersect at this remarkably important protein. There are also meaningful differences. The pharmacokinetic properties are quite different and thus potential routes of delivery differ. ASOs may be designedto use a variety of post-RNA binding mechanismswhile siRNAs depend solely on the robust activity of Ago2. However, siRNAs and ASOs are both used for therapeutic purposes and both must be and can be understood in a pharmacological context. Thus, the goals of this review are to put ASOs in pharmacological context and compare their behavior as pharmacological agents to the those of siRNAs.

Therapeutic and prophylactic deletion of IL-4Ra-signaling ameliorates established ovalbumin induced allergic asthma

Background

Allergic asthma is a chronic inflammatory airway disease driven predominantly by a T_H2 immune response to environmental allergens. IL‐4Rα‐signaling is essential for driving T_H2‐type immunity to allergens. Anti‐T_H2 therapies have the potential to effectively reduce airway obstruction and inflammation in allergic asthma.

Objective

We investigated potential therapeutic effects of selective inhibition of this pathway in mice with established allergic airway disease. We further investigated whether IL‐4Rα disruption in systemically sensitized mice can prevent the onset of the disease.

Methods

We used Rosa^creERT2IL‐4Rα^−/lox mice, a tamoxifen (TAM)‐inducible IL‐4Rα knockdown model to investigate the role of IL‐4/IL‐13 signaling prior to the onset of the disease and during the effector phase in the ovalbumin‐induced allergic airway disease.

Results

Inducible deletion of IL‐4Rα demonstrated therapeutic effects, on established allergic airway disease, and prevented the development of ovalbumin‐induced airway hyperreactivity, eosinophilia, and goblet cell metaplasia in allergen‐sensitized mice. Interestingly, IL‐4Rα knockdown after allergic sensitization did not induce T_H17, a neutrophilic inflammatory response as observed in global IL‐4Rα‐deficient mice after intranasal allergen challenge.

Conclusion

Abrogation of IL‐4Rα signaling after allergic sensitization would have significant therapeutic benefit for T_H2‐type allergic asthma.

Nonsense-mediated RNA Decay Pathway Inhibition Restores Expression and Function of W1282X CFTR

The recessive genetic disease cystic fibrosis (CF) is caused by loss-of-function mutations in the CFTR (CF transmembrane conductance regulator) gene. Approximately 10% of patients with CF have at least one allele with a nonsense mutation in CFTR. Nonsense mutations generate premature termination codons that can subject mRNA transcripts to rapid degradation through the nonsense-mediated mRNA decay (NMD) pathway. Currently, there are no approved therapies that specifically target nonsense mutations in CFTR. Here, we identified antisense oligonucleotides (ASOs) that target the NMD factor SMG1 to inhibit the NMD pathway, and determined their effects on the W1282X CFTR mutation. First, we developed and validated two in vitro models of the W1282X CFTR mutation. Next, we treated these cells with antisense oligonucleotides to inhibit NMD and measured the effects of these treatments on W1282X expression and function. SMG1-ASO-mediated NMD inhibition upregulated the RNA, protein, and surface-localized protein expression of the truncated W1282X gene product. Additionally, these ASOs increased the CFTR chloride channel function in cells homozygous for the W1282X mutation. Our approach suggests a new therapeutic strategy for patients harboring nonsense mutations and may be beneficial as a single agent in patients with CF and the W1282X mutation.

New approaches to genetic therapies for cystic fibrosis

Gene therapy offers great promise for cystic fibrosis which has never been quite fulfilled due to the challenges of delivering sufficient amounts of the CFTR gene and expression persistence for a sufficient period of time in the lungs to have any effect. Initial trials explored both viral and non-viral vectors but failed to achieve a significant breakthrough. However, in recent years, new opportunities have emerged that exploit our increased knowledge and understanding of the biology of CF and the airway epithelium. New technologies include new viral and non-viral vector approaches to delivery, but also alternative nucleic acid technologies including oligonucleotides and siRNA approaches for gene silencing and gene splicing, described in this review, as presented at the 2019 annual European CF Society Basic Science meeting (Dubrovnik, Croatia). We also briefly discuss other emerging technologies including mRNA and CRISPR gene editing that are advancing rapidly. The future prospects for genetic therapies for CF are now diverse and more promising probably than any time since the discovery of the CF gene.

The Aquaporin 5 -1364A/C Promoter Polymorphism Is Associated With Cytomegalovirus Infection Risk in Kidney Transplant Recipients

Background: The aquaporin 5 (AQP5) −1364A/C promoter single nucleotide polymorphism affects key mechanisms of inflammation and immune cell migration. Thus, it could be involved in the pathogenesis of cytomegalovirus infection. Accordingly, we tested the hypothesis that the AQP5 promoter −1364A/C polymorphism is associated with the risk of cytomegalovirus infection in kidney transplantation recipients.

Methods: We included 259 adult patients who received a kidney transplant from 2007 and 2014 in this observational study. Patients were genotyped for the AQP5 promoter −1364A/C single nucleotide polymorphism and followed up for 12 months after transplantation. Kaplan–Meier plots and multivariable proportional hazard analyses were used to evaluate the relationship between genotypes and the incidence of cytomegalovirus infection.

Results: The incidences of cytomegalovirus infection within 12 months after kidney transplantation were 22.9% for the AA genotypes (43/188) and 42.3% for the AC/CC genotypes (30/71; p = 0.002). Furthermore, multivariable COX regression revealed the C-allele of the AQP5 −1364A/C polymorphism to be a strong and independent risk factor for cytomegalovirus infection. In this analysis, AC/CC subjects demonstrated a more than 2-fold increased risk for cytomegalovirus infection within the first year after kidney transplantation (hazard ratio: 2.28; 95% CI: 1.40–3.73; p = 0.001) compared to that in individuals with homozygous AA genotypes.

Conclusions: With respect to opportunistic cytomegalovirus infections (attributable to immunosuppression after kidney transplantation), the C-allele of the AQP5 −1364A/C promoter polymorphism is independently associated with an increased 12-months infection risk. These findings emphasize the importance of genetic variations as additional risk factors of cytomegalovirus infection after solid organ transplantations and might also facilitate the discovery of novel therapeutic targets.

Therapeutic perspectives for structural and functional abnormalities of cilia

Ciliopathies are a group of hereditary disorders that result from structural or functional abnormalities of cilia. Recent intense research efforts have uncovered the genetic bases of ciliopathies, and our understanding of the assembly and functions of cilia has been improved significantly. Although mechanism-specific therapies for ciliopathies have not yet received regulatory approval, the use of innovative therapeutic modalities such as oligonucleotide therapy, gene replacement therapy, and gene editing in addition to symptomatic treatments are expected to provide valid treatment options in the near future. Moreover, candidate chemical compounds for developing small molecule drugs to treat ciliopathies have been identified. This review introduces the key features of cilia and ciliopathies, and summarizes the advances as well as the challenges that remain with the development of therapies for treating ciliopathies.

Complement factor C5 inhibition reduces type 2 responses without affecting group 2 innate lymphoid cells in a house dust mite induced murine asthma model

Background

Complement factor C5 can either aggravate or attenuate the T-helper type 2 (T_H2) immune response and airway hyperresponsiveness (AHR) in murine models of allergic asthma. The effect of C5 during the effector phase of allergen-induced asthma is ill-defined.

Objectives

We aimed to determine the effect of C5 blockade during the effector phase on the pulmonary T_H2 response and AHR in a house dust mite (HDM) driven murine asthma model.

Methods

BALB/c mice were sensitized and challenged repeatedly with HDM via the airways to induce allergic lung inflammation. Sensitized mice received twice weekly injections with a blocking anti-C5 or control antibody 24 h before the first challenge.

Results

HDM challenge in sensitized mice resulted in elevated C5a levels in bronchoalveolar lavage fluid. Anti-C5 administered to sensitized mice prior to the first HDM challenge prevented this rise in C5a, but did not influence the influx of eosinophils or neutrophils. While anti-C5 did not impact the recruitment of CD4 T cells upon HDM challenge, it reduced the proportion of T_H2 cells recruited to the airways, attenuated IL-4 release by regional lymph nodes restimulated with HDM ex vivo and mitigated the plasma IgE response. Anti-C5 did not affect innate lymphoid cell (ILC) proliferation or group 2 ILC (ILC2) differentiation. Anti-C5 attenuated HDM induced AHR in the absence of an effect on lung histopathology, mucus production or vascular leak.

Conclusions

Generation of C5a during the effector phase of HDM induced allergic lung inflammation contributes to T_H2 cell differentiation and AHR without impacting ILC2 cells.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1136-5) contains supplementary material, which is available to authorized users.

The post-cardiac arrest syndrome: A case for lung-brain coupling and opportunities for neuroprotection

Systemic inflammation and multi-organ failure represent hallmarks of the post-cardiac arrest syndrome (PCAS) and predict severe neurological injury and often fatal outcomes. Current interventions for cardiac arrest focus on the reversal of precipitating cardiac pathologies and the implementation of supportive measures with the goal of limiting damage to at-risk tissue. Despite the widespread use of targeted temperature management, there remain no proven approaches to manage reperfusion injury in the period following the return of spontaneous circulation. Recent evidence has implicated the lung as a moderator of systemic inflammation following remote somatic injury in part through effects on innate immune priming. In this review, we explore concepts related to lung-dependent innate immune priming and its potential role in PCAS. Specifically, we propose and investigate the conceptual model of lung-brain coupling drawing from the broader literature connecting tissue damage and acute lung injury with cerebral reperfusion injury. Subsequently, we consider the role that interventions designed to short-circuit lung-dependent immune priming might play in improving patient outcomes following cardiac arrest and possibly other acute neurological injuries.

Biodistribution/biostability assessment of siRNA after intravenous and intratracheal administration to mice, based on comprehensive analysis of in vivo/ex vivo/polyacrylamide gel electrophoresis fluorescence imaging

We performed in vivo/ex vivo/polyacrylamide gel electrophoresis (PAGE) fluorescence imaging of near-infrared fluorescence (NIRF)-labeled siRNA (Cy5.5-siGL3) in mice to investigate the validity of each fluorescence imaging result as the biodistribution/biostability assessment of siRNA. Statistically significant correlations could be obtained between the in vivo and ex vivo fluorescence intensities of Cy5.5 in the relevant regions/tissues, except the lung region/tissue after intravenous administration. On PAGE fluorescence images with the naked formulation, there was no band corresponding to intact Cy5.5-siGL3 from all the tissues evaluated after intravenous administration, indicating that the fluorescence detected by in vivo and ex vivo fluorescence imaging was derived from degraded Cy5.5-siGL3 or free Cy5.5 cleaved from Cy5.5-siGL3. However, the band was detected from the lungs after intratracheal administration of the naked formulation, confirming higher stability of siRNA on the respiratory epithelium than in the blood. Regarding the polyethyleneimine formulation, the band was detected from all the tissues evaluated after intravenous administration and from the lungs after intratracheal administration, verifying the enhanced stability of siRNA in the body. These results clearly indicated the necessity of comprehensive analysis from in vivo/ex vivo/PAGE fluorescence imaging to precisely assess the distribution and stability of NIRF-labeled oligonucleotides including siRNA in the body.

Antisense oligonucleotides selectively suppress target RNA in nociceptive neurons of the pain system and can ameliorate mechanical pain

There is an urgent need for better treatments for chronic pain, which affects more than 1 billion people worldwide. Antisense oligonucleotides (ASOs) have proven successful in treating children with spinal muscular atrophy, a severe infantile neurological disorder, and several ASOs are currently being tested in clinical trials for various neurological disorders. Here, we characterize the pharmacodynamic activity of ASOs in spinal cord and dorsal root ganglia (DRG), key tissues for pain signaling. We demonstrate that activity of ASOs lasts up to 2 months after a single intrathecal bolus dose. Interestingly, comparison of subcutaneous, intracerebroventricular, and intrathecal administration shows that DRGs are targetable by systemic and central delivery of ASOs, while target reduction in the spinal cord is achieved only after direct central delivery. Upon detailed characterization of ASO activity in individual cell populations in DRG, we observe robust target suppression in all neuronal populations, thereby establishing that ASOs are effective in the cell populations involved in pain propagation. Furthermore, we confirm that ASOs are selective and do not modulate basal pain sensation. We also demonstrate that ASOs targeting the sodium channel Nav1.7 induce sustained analgesia up to 4 weeks. Taken together, our findings support the idea that ASOs possess the required pharmacodynamic properties, along with a long duration of action beneficial for treating pain.

Aquaporin water channels: New perspectives on the potential role in inflammation

Aquaporins (AQPs) are a family of membrane water channel proteins that osmotically modulate water fluid homeostasis in several tissues; some of them also transport small solutes such as glycerol. At the cellular level, the AQPs regulate not only cell migration and transepithelial fluid transport across membranes, but also common events that are crucial for the inflammatory response. Emerging data reveal a new function of AQPs in the inflammatory process, as demonstrated by their dysregulation in a wide range of inflammatory diseases including edematous states, cancer, obesity, wound healing and several autoimmune diseases. This chapter summarizes the discoveries made so far about the structure and functions of the AQPs and provides updated information on the underlying mechanisms of AQPs in several human inflammatory diseases. The discovery of new functions for AQPs opens new vistas offering promise for the discovery of mechanisms and therapeutic opportunities in inflammatory disorders.

Kininogen deficiency or depletion reduces enhanced pause independent of pulmonary inflammation in a house dust mite-induced murine asthma model

High-molecular-weight kininogen is an important substrate of the kallikrein-kinin system. Activation of this system has been associated with aggravation of hallmark features in asthma. We aimed to determine the role of kininogen in enhanced pause (Penh) measurements and lung inflammation in a house dust mite (HDM)-induced murine asthma model. Normal wild-type mice and mice with a genetic deficiency of kininogen were subjected to repeated HDM exposure (sensitization on days 0, 1, and 2; challenge on days 14, 15, 18, and 19) via the airways to induce allergic lung inflammation. Alternatively, kininogen was depleted after HDM sensitization by twice-weekly injections of a specific antisense oligonucleotide (kininogen ASO) starting at day 3. In kininogen-deficient mice HDM induced in Penh was completely prevented. Remarkably, kininogen deficiency did not modify HDM-induced eosinophil/neutrophil influx, T helper 2 responses, mucus production, or lung pathology. kininogen ASO treatment started after HDM sensitization reduced plasma kininogen levels by 75% and reproduced the phenotype of kininogen deficiency: kininogen ASO administration prevented the HDM-induced increase in Penh without influencing leukocyte influx, Th2 responses, mucus production, or lung pathology. This study suggests that kininogen could contribute to HDM-induced rise in Penh independently of allergic lung inflammation. Further research is warranted to confirm these data using invasive measurements of airway responsiveness.

Antisense oligonucleotide targeting of mRNAs encoding ENaC subunits α, β, and γ improves cystic fibrosis-like disease in mice

BACKGROUND

The epithelial sodium channel ENaC consists of three subunits encoded by Scnn1a, Scnn1b, and Scnn1g and increased sodium absorption through this channel is hypothesized to lead to mucus dehydration and accumulation in cystic fibrosis (CF) patients.

METHODS

We identified potent and specific antisense oligonucleotides (ASOs) targeting mRNAs encoding the ENaC subunits and evaluated these ASOs in mouse models of CF-like lung disease.

RESULTS

ASOs designed to target mRNAs encoding each ENaC subunit or a control ASO were administered directly into the lungs of mice. The reductions in ENaC subunits correlated well with a reduction in amiloride sensitive channel conductance. In addition, levels of mucus markers Gob5, AGR2, Muc5ac, and Muc5b, periodic acid-Schiff's reagent (PAS) goblet cell staining, and neutrophil recruitment were reduced and lung function was improved when levels of any of the ENaC subunits were decreased.

CONCLUSIONS

Delivery of ASOs targeting mRNAs encoding each of the three ENaC subunits directly into the lung improved disease phenotypes in a mouse model of CF-like lung disease. These findings suggest that targeting ENaC subunits could be an effective approach for the treatment of CF.

PI3Kδ contributes to ER stress-associated asthma through ER-redox disturbances: the involvement of the RIDD-RIG-I-NF-κB axis

Hyperactivation of phosphoinositol 3-kinase (PI3K) has been suggested to be a potential mechanism for endoplasmic reticulum (ER) stress-enhanced airway hyperresponsiveness, and PI3K inhibitors have been examined as asthma therapeutics. However, the regulatory mechanism linking PI3K to ER stress and related pathological signals in asthma have not been defined. To elucidate these pathogenic pathways, we investigated the influence of a selective PI3Kδ inhibitor, IC87114, on airway inflammation in an ovalbumin/lipopolysaccharide (OVA/LPS)-induced asthma model. In OVA/LPS-induced asthmatic mice, the activity of PI3K, downstream phosphorylation of AKT and activation of nuclear factor-κB (NF-κB) were all significantly elevated; these effects were reversed by IC87114. IC87114 treatment also reduced the OVA/LPS-induced ER stress response by enhancing the intra-ER oxidative folding status through suppression of protein disulfide isomerase activity, ER-associated reactive oxygen species (ROS) accumulation and NOX4 activity. Furthermore, inositol-requiring enzyme-1α (IRE1α)-dependent degradation (RIDD) of IRE1α was reduced by IC87114, resulting in a decreased release of proinflammatory cytokines from bronchial epithelial cells. These results suggest that PI3Kδ may induce severe airway inflammation and hyperresponsiveness by activating NF-κB signaling through ER-associated ROS and RIDD–RIG-I activation. The PI3Kδ inhibitor IC87114 is a potential therapeutic agent against neutrophil-dominant asthma.

New Perspectives on the Potential Role of Aquaporins (AQPs) in the Physiology of Inflammation

Aquaporins (AQPs) are emerging, in the last few decades, as critical proteins regulating water fluid homeostasis in cells involved in inflammation. AQPs represent a family of ubiquitous membrane channels that regulate osmotically water flux in various tissues and sometimes the transport of small solutes, including glycerol. Extensive data indicate that AQPs, working as water channel proteins, regulate not only cell migration, but also common events essential for inflammatory response. The involvement of AQPs in several inflammatory processes, as demonstrated by their dysregulation both in human and animal diseases, identifies their new role in protection and response to different noxious stimuli, including bacterial infection. This contribution could represent a new key to clarify the dilemma of host-pathogen communications, and opens up new scenarios regarding the investigation of the modulation of specific AQPs, as target for new pharmacological therapies. This review provides updated information on the underlying mechanisms of AQPs in the regulation of inflammatory responses in mammals and discusses the broad spectrum of options that can be tailored for different diseases and their pharmacological treatment.

The potential of antisense oligonucleotide therapies for inherited childhood lung diseases

Antisense oligonucleotides are an emerging therapeutic option to treat diseases with known genetic origin. In the age of personalised medicines, antisense oligonucleotides can sometimes be designed to target and bypass or overcome a patient's genetic mutation, in particular those lesions that compromise normal pre-mRNA processing. Antisense oligonucleotides can alter gene expression through a variety of mechanisms as determined by the chemistry and antisense oligomer design. Through targeting the pre-mRNA, antisense oligonucleotides can alter splicing and induce a specific spliceoform or disrupt the reading frame, target an RNA transcript for degradation through RNaseH activation, block ribosome initiation of protein translation or disrupt miRNA function. The recent accelerated approval of eteplirsen (renamed Exondys 51™) by the Food and Drug Administration, for the treatment of Duchenne muscular dystrophy, and nusinersen, for the treatment of spinal muscular atrophy, herald a new and exciting era in splice-switching antisense oligonucleotide applications to treat inherited diseases. This review considers the potential of antisense oligonucleotides to treat inherited lung diseases of childhood with a focus on cystic fibrosis and disorders of surfactant protein metabolism.

The intratracheal administration of locked nucleic acid containing antisense oligonucleotides induced gene silencing and an immune-stimulatory effect in the murine lung

Locked nucleic acid containing antisense oligonucleotides (LNA-ASOs) have the potential to modulate the disease-related gene expression by the RNaseH-dependent degradation of mRNAs. Pulmonary drug delivery has been widely used for the treatment of lung disease. Thus, the inhalation of LNA-ASOs is expected to be an efficient therapy that can be applied to several types of lung disease. Because the lung has a distinct immune system against pathogens, the immune-stimulatory effect of LNA-ASOs should be considered for the development of novel inhaled LNA-ASOs therapies. However, there have been no reports on the relationship between knock-down (KD) and the immune-stimulatory effects of inhaled LNA-ASOs in the lung. In this report, LNA-ASOs targeting Scarb1 (Scarb1-ASOs) or negative control LNA-ASOs targeting ApoB (ApoB-ASOs) were intratracheally administered to mice to investigate the KD of the gene expression and the immune-stimulatory effects in the lung. We confirmed that the intratracheal administration of Scarb1-ASOs exerted a KD effect in the lung without a drug delivery system. On the other hand, both Scarb1-ASOs and ApoB-ASOs induced neutrophilic infiltration in the alveoli and increased the expression levels of G-CSF and CXCL1 in the lung. The dose required for KD was the same as the dose that induced the neutrophilic immune response. In addition, in our in vitro experiments, Scarb1-ASOs did not increase the G-CSF or CXCL1 expression in primary lung cells, even though Scarb1-ASOs exerted a strong KD effect. Hence, we hypothesize that inhaled LNA-ASOs have the potential to exert a KD effect in the lung, but that they may be associated with a risk of immune stimulation. Further studies about the mechanism underlying the immune-stimulatory effect of LNA-ASOs is necessary for the development of novel inhaled LNA-ASO therapies.

Genetic Modification of the Lung Directed Toward Treatment of Human Disease

Genetic modification therapy is a promising therapeutic strategy for many diseases of the lung intractable to other treatments. Lung gene therapy has been the subject of numerous preclinical animal experiments and human clinical trials, for targets including genetic diseases such as cystic fibrosis and α1-antitrypsin deficiency, complex disorders such as asthma, allergy, and lung cancer, infections such as respiratory syncytial virus (RSV) and Pseudomonas, as well as pulmonary arterial hypertension, transplant rejection, and lung injury. A variety of viral and non-viral vectors have been employed to overcome the many physical barriers to gene transfer imposed by lung anatomy and natural defenses. Beyond the treatment of lung diseases, the lung has the potential to be used as a metabolic factory for generating proteins for delivery to the circulation for treatment of systemic diseases. Although much has been learned through a myriad of experiments about the development of genetic modification of the lung, more work is still needed to improve the delivery vehicles and to overcome challenges such as entry barriers, persistent expression, specific cell targeting, and circumventing host anti-vector responses.

Inhaled ENaC antisense oligonucleotide ameliorates cystic fibrosis-like lung disease in mice

BACKGROUND

Epithelial sodium channel (ENaC, Scnn1) hyperactivity in the lung leads to airway surface dehydration and mucus accumulation in cystic fibrosis (CF) patients and in mice with CF-like lung disease.

METHODS

We identified several potent ENaC specific antisense oligonucleotides (ASOs) and tested them by inhalation in mouse models of CF-like lung disease.

RESULTS

The inhaled ASOs distributed into lung airway epithelial cells and decreased ENaC expression by inducing RNase H1-dependent degradation of the targeted Scnn1a mRNA. Aerosol delivered ENaC ASO down-regulated mucus marker expression and ameliorated goblet cell metaplasia, inflammation, and airway hyper-responsiveness. Lack of systemic activity of ASOs delivered via the aerosol route ensures the safety of this approach.

CONCLUSIONS

Our results demonstrate that antisense inhibition of ENaC in airway epithelial cells could be an effective and safe approach for the prevention and reversal of lung symptoms in CF and potentially other inflammatory diseases of the lung.

Dupilumab for the treatment of asthma

INTRODUCTION

Dupilumab (REGN668/SAR231893), produced by a collaboration between Regeneron and Sanofi, is a monoclonal antibody currently in phase III for moderate-to-severe asthma. Dupilumab is directed against the α-subunit of the interleukin (IL)-4 receptor and blocks the IL-4 and IL-13 signal transduction. Areas covered: Pathophysiological role of IL-4 and IL-13 in asthma; mechanism of action of dupilumab; pharmacology of IL-4 receptor; phase I and phase II studies with dupilumab; regulatory affairs. Expert opinion: Patients with severe asthma who are not sufficiently controlled with standard-of-care represent the target asthma population for dupilumab. If confirmed, efficacy of dupilumab in both eosinophilic and non-eosinophilic severe asthma phenotype might represent an advantage over approved biologics for asthma, including omalizumab, mepolizumab, and reslizumab. Head-to-head studies to compare dupilumab versus other biologics with different mechanism of action are required. Pediatric studies with dupilumab are currently lacking and should be undertaken to assess efficacy and safety of this drug in children with severe asthma. The lack of preclinical data and published results of the completed four phase I studies precludes a complete assessment of the pharmacological profile of dupilumab. Dupilumab seems to be generally well tolerated, but large studies are required to establish its long-term safety and tolerability.

Oligonucleotide Therapy for Obstructive and Restrictive Respiratory Diseases

Inhaled oligonucleotide is an emerging therapeutic modality for various common respiratory diseases, including obstructive airway diseases like asthma and chronic obstructive pulmonary disease (COPD) and restrictive airway diseases like idiopathic pulmonary fibrosis (IPF). The advantage of direct accessibility for oligonucleotide molecules to the lung target sites, bypassing systemic administration, makes this therapeutic approach promising with minimized potential systemic side effects. Asthma, COPD, and IPF are common chronic respiratory diseases, characterized by persistent airway inflammation and dysregulated tissue repair and remodeling, although each individual disease has its unique etiology. Corticosteroids have been widely prescribed for the treatment of asthma, COPD, and IPF. However, the effectiveness of corticosteroids as an anti-inflammatory drug is limited by steroid resistance in severe asthma, the majority of COPD cases, and pulmonary fibrosis. There is an urgent medical need to develop target-specific drugs for the treatment of these respiratory conditions. Oligonucleotide therapies, including antisense oligonucleotide (ASO), small interfering RNA (siRNA), and microRNA (miRNA) are now being evaluated both pre-clinically and clinically as potential therapeutics. The mechanisms of action of ASO and siRNA are highly target mRNA specific, ultimately leading to target protein knockdown. miRNA has both biomarker and therapeutic values, and its knockdown by a miRNA antagonist (antagomir) has a broader but potentially more non-specific biological outcome. This review will compile the current findings of oligonucleotide therapeutic targets, verified in various respiratory disease models and in clinical trials, and evaluate different chemical modification approaches to improve the stability and potency of oligonucleotides for the treatment of respiratory diseases.

Clinical potential of oligonucleotide-based therapeutics in the respiratory system

The discovery of an ever-expanding plethora of coding and non-coding RNAs with nodal and causal roles in the regulation of lung physiology and disease is reinvigorating interest in the clinical utility of the oligonucleotide therapeutic class. This is strongly supported through recent advances in nucleic acids chemistry, synthetic oligonucleotide delivery and viral gene therapy that have succeeded in bringing to market at least three nucleic acid-based drugs. As a consequence, multiple new candidates such as RNA interference modulators, antisense, and splice switching compounds are now progressing through clinical evaluation. Here, manipulation of RNA for the treatment of lung disease is explored, with emphasis on robust pharmacological evidence aligned to the five pillars of drug development: exposure to the appropriate tissue, binding to the desired molecular target, evidence of the expected mode of action, activity in the relevant patient population and commercially viable value proposition.

Local and systemic tolerability of a 2'O-methoxyethyl antisense oligonucleotide targeting interleukin-4 receptor-α delivery by inhalation in mouse and monkey

Antisense oligonucleotides (ASOs) bind and facilitate degradation of RNA and inhibit protein expression in pathways not easily targeted with small molecules or antibodies. Interleukin (IL)-4 and IL-13 potentiate signaling through the shared IL-4 receptor-α (IL-4Rα) subunit of their receptors. ASO targeting of IL-4Rα mRNA in a mouse model of asthma led to attenuation of airway hyperactivity, demonstrating potential benefit in asthma patients. This study focused on tolerability of inhaled IL-4Rα-targeting ASOs. Toxicity studies were performed with mouse- (ISIS 23189) and human-specific (ISIS 369645) sequences administered by inhalation. Four week (monkey) or 13 week (mouse) repeat doses at levels of up to 15 mg/kg/exposure (exp) and 50 mg/kg/exp, respectively, demonstrated dose-dependent effects limited to increases in macrophage size and number in lung and tracheobronchial lymph nodes. The changes were largely non-specific, reflecting adaptive responses that occur during active exposure and deposition of ASO and other material in the lung. Reversibility was observed at a rate consistent with the kinetics of tissue clearance of ASO. Systemic bioavailability was minimal, and no systemic toxicity was observed at exposure levels appreciably above pharmacological doses and doses proposed for clinical trials.

Small interfering RNAs targeted to interleukin-4 and respiratory syncytial virus reduce airway inflammation in a mouse model of virus-induced asthma exacerbation

Asthma exacerbations are caused primarily by viral infections. Antisense and small interfering RNA (siRNA) technologies have gained attention as potential antiasthma and antiviral approaches. In this study we analyzed whether gene silencing of interleukin (IL)-4 expression and respiratory syncytial virus (RSV) replication by RNA interference is able to suppress allergen- and virus-induced responses in a mouse model of virus-induced asthma exacerbation. Knockdown efficacy of IL-4 siRNA molecules was analyzed in the human HEK293T cell line by cotransfection of six different siRNAs with a plasmid carrying mouse IL-4. The most potent siRNA was then used in a mouse model of RSV-induced asthma exacerbation. BALB/c mice were sensitized intraperitoneally with ovalbumin (OVA) and then infected 12 days later intranasally with RSV Long strain (1×10(6) TCID50/mouse), followed 1 day later by intranasal challenge with OVA for 3 days. Mice were pretreated intranasally three times with either siRNA to IL-4 or GFP control, 2 days before, and on the first two OVA challenge days. siRNAs to RSV or rhinovirus control were inoculated intranasally once, 3 hr before RSV infection. Combined anti-IL-4 and anti-RSV siRNAs were able to significantly reduce total cell counts and eosinophilia in bronchoalveolar lavage fluid, development of airway hyperresponsiveness, and airway inflammation and to downregulate IL-4 mRNA expression and RSV viral RNA, but to upregulate IFN-γ levels in lung tissues. We conclude that anti-helper T cells type 2 and antiviral siRNAs may constitute a new therapeutic approach for treatment of virus induced asthma exacerbations.

Compartmental and temporal dynamics of chronic inflammation and airway remodelling in a chronic asthma mouse model

BACKGROUND

Allergic asthma is associated with chronic airway inflammation and progressive airway remodelling. However, the dynamics of the development of these features and their spontaneous and pharmacological reversibility are still poorly understood. We have therefore investigated the dynamics of airway remodelling and repair in an experimental asthma model and studied how pharmacological intervention affects these processes.

METHODS

Using BALB/c mice, the kinetics of chronic asthma progression and resolution were characterised in absence and presence of inhaled corticosteroid (ICS) treatment. Airway inflammation and remodelling was assessed by the analysis of bronchoalveolar and peribronichal inflammatory cell infiltrate, goblet cell hyperplasia, collagen deposition and smooth muscle thickening.

RESULTS

Chronic allergen exposure resulted in early (goblet cell hyperplasia) and late remodelling (collagen deposition and smooth muscle thickening). After four weeks of allergen cessation eosinophilic inflammation, goblet cell hyperplasia and collagen deposition were resolved, full resolution of lymphocyte inflammation and smooth muscle thickening was only observed after eight weeks. ICS therapy when started before the full establishment of chronic asthma reduced the development of lung inflammation, decreased goblet cell hyperplasia and collagen deposition, but did not affect smooth muscle thickening. These effects of ICS on airway remodelling were maintained for a further four weeks even when therapy was discontinued.

CONCLUSIONS

Utilising a chronic model of experimental asthma we have shown that repeated allergen exposure induces reversible airway remodelling and inflammation in mice. Therapeutic intervention with ICS was partially effective in inhibiting the transition from acute to chronic asthma by reducing airway inflammation and remodelling but was ineffective in preventing smooth muscle hypertrophy.

An IL-4/IL-13 dual antagonist reduces lung inflammation, airway hyperresponsiveness, and IgE production in mice

IL-4 and IL-13 comprise promising targets for therapeutic interventions in asthma and other Th2-associated diseases, but agents targeting either IL-4 or IL-13 alone have shown limited efficacy in human clinical studies. Because these cytokines may involve redundant function, dual targeting holds promise for achieving greater efficacy. We describe a bifunctional therapeutic targeting IL-4 and IL-13, developed by a combination of specific binding domains. IL-4-targeted and IL-13-targeted single chain variable fragments were joined in an optimal configuration, using appropriate linker regions on a novel protein scaffold. The bifunctional IL-4/IL-13 antagonist displayed high affinity for both cytokines. It was a potent and efficient neutralizer of both murine IL-4 and murine IL-13 bioactivity in cytokine-responsive Ba/F3 cells, and exhibited a half-life of approximately 4.7 days in mice. In a murine model of ovalbumin-induced ear swelling, the bifunctional molecule blocked both the IL-4/IL-13-dependent early-phase response and the IL-4-dependent late-phase response. In the ovalbumin-induced lung inflammation model, the bifunctional IL-4/IL-13 antagonist reduced the IL-4-dependent rise in serum IgE titers, and reduced IL-13-dependent airway hyperresponsiveness, lung inflammation, mucin gene expression, and serum chitinase responses. Taken together, these findings demonstrate the effective dual blockade of IL-4 and IL-13 with a single agent, which resulted in the modulation of a more extensive range of endpoints than could be achieved by targeting either cytokine alone.