Gene therapy for allergic airway diseases

Cang-ai volatile oil alleviates nasal inflammation via Th1/Th2 cell imbalance regulation in a rat model of ovalbumin-induced allergic rhinitis

We previously revealed that Cang-ai volatile oil (CAVO) regulates T-cell activity, enhancing the immune response in people with chronic respiratory diseases. However, the effects of CAVO on allergic rhinitis (AR) have not been investigated. Herein, we established an ovalbumin (OVA)-induced AR rat model to determine these effects. Sprague-Dawley (SD) rats were exposed to OVA for 3 weeks. CAVO or loratadine (positive control) was given orally once daily for 2 weeks to OVA-exposed rats. Behavior modeling nasal allergies was observed. Nasal mucosa, serum, and spleen samples of AR rats were analyzed. CAVO treatment significantly reduced the number of nose rubs and sneezes, and ameliorated several hallmarks of nasal mucosa tissue remodeling: inflammation, eosinophilic infiltration, goblet cell metaplasia, and mast cell hyperplasia. CAVO administration markedly upregulated expressions of interferon-γ, interleukin (IL)-2, and IL-12, and downregulated expressions of serum tumor necrosis factor-α, IL-4, IL-5, IL-6, IL-13, immunoglobulin-E, and histamine. CAVO therapy also increased production of IFN-γ and T-helper type 1 (Th1)-specific T-box transcription factor (T-bet) of the cluster of differentiation-4+ T-cells in splenic lymphocytes, and protein and mRNA expressions of T-bet in nasal mucosa. In contrast, levels of the Th2 cytokine IL-4 and Th2-specific transcription factor GATA binding protein-3 were suppressed by CAVO. These cumulative findings demonstrate that CAVO therapy can alleviate AR by regulating the balance between Th1 and Th2 cells.

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.

Mechanism of Kruppel-Like Factor 4 in Pyroptosis of Nasal Mucosal Epithelial Cells in Mice With Allergic Rhinitis

BACKGROUND

Allergic rhinitis (AR) is a chronic nasal inflammation, characterized by nasal epithelial dysfunction. Gene therapy targeting transcription factors is a promising strategy for quenching allergic inflammation, including AR.

OBJECTIVE

This study sought to probe the mechanism of Kruppel-like factor 4 (KLF4) in pyroptosis of nasal mucosal epithelial cells (NEpCs) in AR mice and provide targets for AR treatment.

METHODS

AR mouse models were established using sensitization with ovalbumin, followed by injection with short hairpin RNA KLF4 (sh-KLF4). AR symptoms were assessed by the times of sneezing and nose rubbing, hematoxylin-eosin, and periodic acid-Schiff staining. Levels of KLF4, nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3), cleaved caspase-1, and N-terminal domain (GSDMD-N) in nasal mucosal tissues were determined by Western blot assay, and levels of interleukin (IL)-1β and IL-18 in nasal lavage fluid were determined by enzyme-linked immunosorbent assay. The binding of KLF4 to the NLRP3 promoter was verified using chromatin immunoprecipitation and dual-luciferase assays. The functional rescue experiment was performed with oe-NLRP3 and sh-KLF4 in AR mice.

RESULTS

KLF4 was upregulated in nasal mucosal tissues of AR mice. KLF4 inhibition reduced the times of sneezing and nose rubbing, inflammatory cell infiltration, and goblet cell hyperplasia in nasal mucosal tissues, and levels of NLRP3, cleaved caspase-1, GSDMD-N, IL-1β, and IL-18. KLF4 was enriched on the NLRP3 promoter and improved NLRP3 expression. NLRP3 overexpression reversed the inhibition of sh-KLF4 on pyroptosis of NEpCs in AR mice.

CONCLUSION

KLF4 bound to the NLRP3 promoter and promoted pyroptosis of NEpCs in AR mice via activating NLRP3.

Pulmonary delivery nanomedicines towards circumventing physiological barriers: Strategies and characterization approaches

Pulmonary delivery of nanomedicines is very promising in lung local disease treatments whereas several physiological barriers limit its application via the interaction with inhaled nanomedicines, namely bio-nano interactions. These bio-nano interactions may affect the pulmonary fate of nanomedicines and impede the distribution of nanomedicines in its targeted region, and subsequently undermine the therapeutic efficacy. Pulmonary diseases are under worse scenarios as the altered physiological barriers generally induce stronger bio-nano interactions. To mitigate the bio-nano interactions and regulate the pulmonary fate of nanomedicines, a number of manipulating strategies were established based on size control, surface modification, charge tuning and co-delivery of mucolytic agents. Visualized and non-visualized characterizations can be employed to validate the robustness of the proposed strategies. This review provides a guiding overview of the physiological barriers affecting the in vivo fate of inhaled nanomedicines, the manipulating strategies, and the validation methods, which will assist with the rational design and application of pulmonary nanomedicine.

miRNA-205-5p can be related to T2-polarity in Chronic Rhinosinusitis with Nasal Polyps

BACKGROUND

microRNAs (miRNAs) are directly associated with inflammatory response, but their direct role in CRSwNP (chronic rhinosinusitis with nasal polyps) remains evasive. This study aimed to compare the expression of several miRNAs in tissue samples obtained from patients with CRSwNP and controls and to evaluate if miRNAs correlate to a specific inflammatory pattern (T1, T2, T17, and Treg) or intensity of symptoms in CRSwNP.

METHODS

nasal polyps (from patients with CRSwNP - n=36) and middle turbinate mucosa (from control patients - n=41) were collected. Microarray determined human mature miRNA expression, and the results obtained were validated by qPCR. miRNAs that were differentially expressed were then correlated to cytokine proteins (by Luminex), tissue eosinophilia, and SNOT-22.

RESULTS

After microarray and qPCR analyses, six microRNAs were up-regulated in CRSwNP samples when compared with controls: miR-205-5p, miR-221-3p, miR-222-3p, miR-378a-3p, miR-449a and miR-449b-5p. All these miRNAs are directly implicated with cell cycle regulation and apoptosis, and to a minor extent, with inflammation. Importantly, miR-205-5p showed a significantly positive correlation with IL-5 concentration and eosinophil count at the tissue and with the worst SNOT-22 score.

CONCLUSIONS

miRNA 205-5p was increased in CRSwNP compared to controls, and it was especially expressed in CRSwNP patients with higher T2 inflammation (measured by both IL-5 levels and local eosinophilia) and worst clinical presentation. This miRNA may be an interesting target to be explored in patients with CRSwNP.

MicroRNA-29a promotes the proliferation of human nasal epithelial cells and inhibits their apoptosis and promotes the development of allergic rhinitis by down-regulating FOS expression

OBJECTIVE

To explore the regulation of microRNA-29a (miR-29a) on FOS in human nasal epithelial cells and its molecular mechanism, as well as the effects of miR-29a on the cell proliferation and apoptosis.

METHODS

By cell transfection, gene silencing, quantitative real-time polymerase chain reaction (qRT-PCR), flow cytometry and TUNEL assay (for cell apoptosis), CCK-8 assay (for cell proliferation), dual-luciferase reporter gene assay and Western Blot, it was validated that miR-29a promoted the proliferation of human nasal epithelial cells and inhibited their apoptosis by down-regulating FOS expression in RPMI2650 and HNEpC cell lines.

RESULTS

①Compared with healthy controls, miR-29a expression was up-regulated and FOS mRNA expression was down-regulated in the nasal tissues from the patients with allergic rhinitis (AR). ②MiR-29a over-expression promoted the proliferation of RPMI2650 cells and HNEpC cells but inhibited their apoptosis. ③MiR-29a targeted at FOS. ④MiR-29a over-expression and FOS silencing both significantly promoted cell proliferation and inhibited cell apoptosis. After transfection with both miR-29a and FOS, there was a decrease in the proliferation but an increase in the apoptosis of cells.⑤MiR-29a promoted the proliferation of human nasal epithelial cells and inhibited their apoptosis by down-regulating FOS expression.

CONCLUSION

MiR-29a-/FOS axis can be regarded as a potential marker and a new therapy for AR.

MicroRNA Targets for Asthma Therapy

Asthma is a chronic inflammatory obstructive lung disease that is stratified into endotypes. Th2 high asthma is due to an imbalance of Th1/Th2 signaling leading to abnormally high levels of Th2 cytokines, IL-4, IL-5, and IL-13 and in some cases a reduction in type I interferons. Some asthmatics express Th2 low, Th1/Th17 high phenotypes with or without eosinophilia. Most asthmatics with Th2 high phenotype respond to beta-adrenergic agonists, muscarinic antagonists, and inhaled corticosteroids. However, 5-10% of asthmatics are not well controlled by these therapies despite significant advances in lung immunology and the pathogenesis of severe asthma. This problem is being addressed by developing novel classes of anti-inflammatory agents. Numerous studies have established efficacy of targeting pro-inflammatory microRNAs in mouse models of mild/moderate and severe asthma. Current approaches employ microRNA mimics and antagonists designed for use in vivo. Chemically modified oligonucleotides have enhanced stability in blood, increased cell permeability, and optimized target specificity. Delivery to lung tissue limits clinical applications, but it is a tractable problem. Future studies need to define the most effective microRNA targets and effective delivery systems. Successful oligonucleotide drug candidates must have adequate lung cell uptake, high target specificity, and efficacy with tolerable off-target effects.

Pulmonary siRNA delivery for lung disease: Review of recent progress and challenges

Lung diseases are a leading cause of mortality worldwide and there exists urgent need for new therapies. Approval of the first siRNA treatments in humans has opened the door for further exploration of this therapeutic strategy for other disease states. Pulmonary delivery of siRNA-based biopharmaceuticals offers the potential to address multiple unmet medical needs in lung-related diseases because of the specific physiology of the lung and characteristic properties of siRNA. Inhalation-based siRNA delivery designed for efficient, targeted delivery to specific cells within the lung holds great promise. Efficient delivery of siRNA directly to the lung, however, is relatively complex. This review focuses on the barriers that impact pulmonary siRNA delivery and successful recent approaches to advance this field forward. We focus on the pulmonary barriers that affect siRNA delivery, the disease-dependent pathological changes and their role in pulmonary disease and impact on siRNA delivery, as well as the recent development on the pulmonary siRNA delivery systems.

Nanoparticle-based thymulin gene therapy therapeutically reverses key pathology of experimental allergic asthma

Despite long-standing efforts to enhance care for chronic asthma, symptomatic treatments remain the only option to manage this highly prevalent and debilitating disease. We demonstrate that key pathology of allergic asthma can be almost completely resolved in a therapeutic manner by inhaled gene therapy. After the disease was fully and stably established, we treated mice intratracheally with a single dose of thymulin-expressing plasmids delivered via nanoparticles engineered to have a unique ability to penetrate the airway mucus barrier. Twenty days after the treatment, we found that all key pathologic features found in the asthmatic lung, including chronic inflammation, pulmonary fibrosis, and mechanical dysregulation, were normalized. We conducted tissue- and cell-based analyses to confirm that the therapeutic intervention was mediated comprehensively by anti-inflammatory and antifibrotic effects of the therapy. We believe that our findings open a new avenue for clinical development of therapeutically effective gene therapy for chronic asthma.

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.

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.

Identification of novel targets for seasonal allergic rhinitis during and outside the pollen season by microarray analysis

CONCLUSION

FOS, JUN, and DUSP1 could be used as candidate targets for the treatment of seasonal allergic rhinitis (SAR) during the pollen season, while KLF4 and CD163 could be used as candidate targets outside the pollen season.

OBJECTIVES

The aim of this study is to screen novel genes related to SAR during and outside the pollen season, by using microarray analysis.

METHODS

The mRNA expression profile (GSE50101) of CD4(+) T cells from SAR and healthy controls during and outside the pollen season was downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) were then screened with the cut-off criteria of fold change larger than 1.5 and p-value less than 0.05.

RESULTS

A total of 47 DEGs were identified. Ten DEGs were shared by SAR patient samples during and outside the pollen season, while four and 23 DEGs were specific to during and outside the pollen season, respectively. Five miRNAs were screened in this study. Among these miRNAs, miR-139, miR-101, miR-29A, and miR-181 could target FOS; miR-200 and miR-29A could target KLF4; miR-101 and miR-200 could target DUSP1; miR-139 and miR-181 could target JUN and CD163, respectively.

Nanocomplexes for gene therapy of respiratory diseases: Targeting and overcoming the mucus barrier

Gene therapy, i.e. the delivery and expression of therapeutic genes, holds great promise for congenital and acquired respiratory diseases. Non-viral vectors are less toxic and immunogenic than viral vectors, although they are characterized by lower efficiency. However, they have to overcome many barriers, including inflammatory and immune mediators and cells. The respiratory and airway epithelial cells, the main target of these vectors, are coated with a layer of mucus, which hampers the effective reaching of gene therapy vectors carrying either plasmid DNA or small interfering RNA. This barrier is thicker in many lung diseases, such as cystic fibrosis. This review summarizes the most important advancements in the field of non-viral vectors that have been achieved with the use of nanoparticulate (NP) systems, composed either of polymers or lipids, in the lung gene delivery. In particular, different strategies of targeting of respiratory and airway lung cells will be described. Then, we will focus on the two approaches that attempt to overcome the mucus barrier: coating of the nanoparticulate system with poly(ethylene glycol) and treatment with mucolytics. Our conclusions are: 1) Ligand and physical targeting can direct therapeutic gene expression in specific cell types in the respiratory tract; 2) Mucopenetrating NPs are endowed with promising features to be useful in treating respiratory diseases and should be now advanced in pre-clinical trials. Finally, we discuss the development of such polymer- and lipid-based NPs in the context of in vitro and in vivo disease models, such as lung cancer, as well as in clinical trials.

Effect of RNA interference therapy on the mice eosinophils CCR3 gene and granule protein in the murine model of allergic rhinitis

OBJECTIVE

To observe the clinical manifestations of allergic rhinitis mice and the expression changes of the eosinophils CCR3 and the granule protein mRNA in the bone marrow, peripheral blood and nasal lavage fluid.

METHODS

Twenty-four BALB/c mice were randomly divided into the control group, PBS therapy group, siRNA therapy group and the CCR3 siRNA therapy group (n=6). Allergic rhinitis model were sensitized and stimulated by ovalbunfin, and CCR3 siRNA therapy group were administered with CCR3 transnasally before stimulated. The levels of the eosinophils CCR3, MBP, ECP and EPO in bone marrow, peripheral blood and nasal lavage fluid were detected by RT-PCR.

RESULTS

Compared to the control group and CCR3 siRNA therapy group, the nasal mucosa of the PBS therapy group and siRNA therapy group developed epithalaxy, goblet cells hyperplasia, squamous epithelium metaplasia, epithelium necrosis, lamina propria and submucosa gland hyperplasia, vasodilatation, tissue edema, and the characterized eosinophil infiltration. RT-PCR indicated that the CCR3 mRNA, MBP, ECP and EPO expression in bone marrow, peripheral blood and nasal lavage fluid of the CCR3 siRNA therapy group was lower than the PBS therapy group and siRNA therapy group (P<0.05).

CONCLUSIONS

The RNA interference therapy to CCR3 by local administration pernasal can suppress the process of the development, migration and invasion of the allergic rhinitis eosinophil, thus can reduce the effect of eosinophils and then reduce the inflammation effect of the allergic rhinitis. It may be a new treatment for respiratory tract allergic inflammation.

Regulatory effect of microRNA-135a on the Th1/Th2 imbalance in a murine model of allergic rhinitis

Allergic rhinitis (AR) is primarily caused by a T helper cell (Th)1/Th2 imbalance. In a murine AR model of a previous study, the serum ovalbumin (OVA)-sIgE concentration was high, whereas microRNA (miR)-135a was lowly expressed in the nasal mucosa. The abnormal expression pattern of miR-135a coincided with highly expressed endogenous factors, including GATA binding protein (GATA)-3 and interleukin (IL)-4, and lowly expressed factors, including T-box expressed in T cells (T-bet) and interferon (IFN)-γ. We hypothesized that miR-135a may play an important role in immune regulation in AR mice. In the present study, AR was induced by OVA in the mice. Two groups of the AR mice were treated with a miR-135a mimic and a mimic control, respectively. The serum and nasal mucosa were collected for analysis. Following miR-135a application, the serum OVA-sIgE concentration was significantly reduced. In the nasal mucosa, the expression levels of miR-135a were higher, the mRNA and protein expression levels of GATA-3 and IL-4 were lower, and the expression levels of T-bet and IFN-γ were higher. The miR-135a corrected the Th1/Th2 imbalance in the AR mice. Findings of this study may provide a basis for novel genetic treatments in addressing allergic diseases.

Bottom-up assembly of RNA nanoparticles containing phi29 motor pRNA to silence the asthma STAT5b gene

Activation of the transcription factor signal transducer and activator of transcription 5b (STAT5b) is a key event in the development of asthma. The potent ability of small interfering RNA (siRNA) to inhibit the expression of STAT5b mRNA has provided a new class of therapeutics for asthma. However, efficient delivery of siRNAs remains a key obstacle to their successful application. A targeted intracellular delivery approach for siRNA to specific cell types would be highly desirable. We used packaging RNA (pRNA), a component of the bacteriophage phi29-packaging motor, to deliver STAT5b siRNA to asthmatic spleen lymphocytes. This pRNA was able to spontaneously carry siRNA/STAT5b and aptamer/CD4, which is a ligand to CD4 molecule. Based on RT-PCR data, the pRNA dimer effectively inhibited STAT5b gene mRNA expression of asthmatic spleen lymphocytes, without the need for additional transfections. We conclude that the pRNA dimer carrying both siRNA and aptamer can deliver functional siRNA to cells; possibly, the aptamer acts as a ligand to interact with specific receptors. The pRNAs were evaluated with a CCK-8 kit and were found to have little cytotoxicity. We conclude that pRNA as a novel nanovehicle for RNA worth further study.

MicroRNA-21* regulates the prosurvival effect of GM-CSF on human eosinophils

Eosinophils are the principal effector cells of allergic inflammation, and hematopoietic cytokine granulocyte macrophage colony-stimulating factor (GM-CSF) is the primary cytokine that activates and prolongs the survival of eosinophils in local inflammatory sites by mediating anti-apoptotic activity in allergic inflammation. To investigate the immunopathological role of microRNA (miRNA) in allergic inflammation, we elucidated the regulatory mechanisms of miRNA on the GM-CSF-mediated in vitro survival in eosinophils. Eosinophils were purified from fresh human peripheral blood buffy coat fraction obtained from adult volunteer using microbead magnetic cell sorting. The apoptosis, viability and phosphorylation of extracellular signal-regulated kinase (ERK) were assessed by flow cytometry, and the expression of miRNA was analyzed using Agilent Human miRNA Microarray with Human miRNA Microarray Version 3 and real time RT-PCR. We have confirmed the increased in vitro viability of GM-CSF-treated eosinophils and upregulated expression of miRNA-21* (miR-21*), a complementary miRNA of miR-21, in GM-CSF-treated eosinophils. The transfection of pre-miR miR-21* precursor molecule could up-regulate the miR-21* expression, subsequently enhance the GM-CSF-activated ERK pathway and reverse the apoptosis of eosinophils, while anti-miR-21* inhibitor could down-regulate the miR-21* expression, suppress the GM-CSF-activated ERK pathway and enhance the apoptosis. Our results should shed light on the potential immunopathological role of miRNA-21* regulating the in vitro apoptosis of eosinophils and development of novel molecular treatment of allergic inflammation.

Targeting interleukin-4 in asthma: lost in translation?

The first discovery that interleukin-4 (IL-4) is crucial in the development of allergic airway inflammation originates from the early 1990s. Whereas initial studies in experimental animal models provided the community with the optimistic view that targeting IL-4 would be the ultimate solution for treating asthma, the translation of these findings to the clinic has not been evident and has not yet fulfilled the expectations. Many technical challenges have been encountered in the attempts to modulate IL-4 expression or activity and in transferring knowledge of preclinical studies to clinical trials. Moreover, biological redundancies between IL-4 and IL-13 have compelled a simultaneous blockade of both cytokines. A number of phase I/II studies are now providing us with clinical evidence that targeting IL-4/IL-13 may provide some clinical benefit. However, the initial view that asthma is a purely Th2-mediated disease had to be revised. Currently, different asthma phenotypes have been described, implying that blocking specifically Th2 cytokines, such as IL-4, IL-5, and IL-13, should be targeted to only a specific subset of patients. Taking this into consideration, IL-4 (together with IL-13) deserves attention as subject of further investigations to treat asthma. In this review, we will address the role of IL-4 in asthma, describe IL-4 signaling, and give an overview of preclinical and clinical studies targeting the IL-4 Receptor pathway.

Downregulation of Orai1 expression in the airway alleviates murine allergic rhinitis

Orai1 is the key subunit of the Ca(2+)-release-activated Ca(2+) channel. Our previous report has demonstrated that Orai1 expression in the airway was upregulated in the ovalbumin (OVA)-induced allergic rhinitis (AR) mouse models. To observe whether inhibition of Orai1 expression in the airway could suppress symptoms in a murine model of AR and to assess the impacts of this inhibition on the responses of local and systemic immunocytes, we administered recombinant lentivirus vectors that encoded shRNA against ORAI1 (lenti-ORAI1) into the nostrils of OVA-sensitized mice before the challenges, and analyzed its effect on allergic responses, as compared with the unsensitized mice and untreated AR mice. Administration of lenti-ORAI1 into the nasal cavity successfully infected cells in the epithelial layer of the nasal mucosa, and significantly decreased the frequencies of sneezing and nasal rubbing of the mice. Protein levels of leukotriene C4, OVA-specific IgE, and IL-4 in the nasal lavage fluid and serum and eosinophil cation protein in the serum were also significantly reduced by lenti-ORAI1, as were the mRNA levels of these factors in the nasal mucosa and spleen. These data suggested that administration of lenti-ORAI1 into the nasal cavity effectively decreased Orai1 expression in the nasal mucosa, alleviated AR symptoms, and partially inhibited the hyperresponsiveness of the local and systemic immune cells including T cells, B cells, mast cells and eosinophils that are involved in the pathogenesis of AR.

Small animals models for drug discovery

There has been an explosion of studies of animal models of asthma in the past 20 years. The elucidation of fundamental immunological mechanisms underlying the development of allergy and the complex cytokine and chemokines networks underlying the responses have been substantially unraveled. Translation of findings to human asthma have been slow and hindered by the varied phenotypes that human asthma represents. New areas for expansion of modeling include virally mediated airway inflammation, oxidant stress, and the interactions of stimuli triggering innate immune and adaptive immune responses.